Questions and answers

Questions and answers

Question

"With all the personal health monitoring software and technology (monitoring blood pressure, heart rate, etc.) becoming available to the average person, do you foresee a decline in the need for doctors to diagnose conditions such as hypertension or irregular heartbeats? Is healthcare becoming automated?" - Jessie, Age 17, Milton, ON, May 8, 2013

Answer

Hi Jesse, great question! Healthcare is not yet automated, but the ways in which patients can contribute to their healthcare is certainly changing through a variety of new technologies. There are an increasing number of ways for people to monitor different aspects of how their body is functioning without needing to visit a doctor’s office or hospital. However, observations such as blood pressure, heart rate and rhythm and blood sugar measurements need to be combined with other information such as patient history, symptoms and a physical examination by a medical professional (e.g. a nurse practitioner or physician) to arrive at a confident diagnosis and develop a treatment plan.

- Dr. Joel Kirsch, Staff Cardiologist, Cardiology, Staff Physician, Critical Care Medicine, The Hospital for Sick Children (SickKids); Project Investigator, Research Institute; Associate Professor, Paediatrics, University of Toronto.

Question

"I am interested in knowing if any treatment or cure for Adrenoleukodystrophy, is being discovered. Thank you for your feedback.". - Angie Keshwar, Age 48, Trinidad and Tobago, April 24, 2013

Answer

Thank you for this question. Adrenoleukodystrophy is a rare progressive genetic condition which primarily affects males. In its most severe form it causes an inflammatory brain disease as well as affecting the adrenal glands in the body, important for salt and sugar balance. The most at risk period for the brain disease is in boys aged from three years old to the mid-teens. In adult males and a proportion of women carrying the affected gene, there is a spectrum of neurological effects and the adrenal gland dysfunction.

At this point in time there is no proven cure for the condition; the mainstay of therapy is supportive care. Specific treatments include the use of Lorenzo's oil and a low fat diet. Lorenzo's oil is a mixture of two long chain fats that appears to decrease the elevation of the very long chain fatty acids that is caused by the biochemical abnormality in this condition. Its potential benefit is in presymptomatic boys, where it may delay or reduce the risk of developing the severe brain disease. It is important to know that without Lorenzo's oil, and once the brain disease has started there is no proven benefit of a fat restricted diet. Likewise Lorenzo's oil may not be easily available outside of research studies.

The mainstay of therapy is by surveillance for the development of the brain disease and use of hormone replacement if there is adrenal dysfunction. This is done by regular MRI brain scan as well as neuropsychological assessment to look for changes in behavior during the at risk age period. If there were early signs consistent with disease progression then a bone marrow or stem cell transplantation would be the treatment of choice. Regular follow-up is vital often by a combination of doctors including a metabolic geneticist, a neurologist and an endocrinologist to monitor evidence of the adrenal gland dysfunction.

More recently researchers in France have started gene therapy trials where they are attempting to correct the faulty gene in the body of boys with ALD. Other research studies are using agents to decrease the brain inflammation.

- Dr. Julian Raiman, Staff Physician, Clinical and Metabolic Genetics, Project Investigator, Research Institute, The Hospital for Sick Children (SickKids); Assistant Professor, University of Toronto.

Question

"Why do we have a nose that sticks out of our face and not just two holes for breathing?" Speranca, Age 15, Windsor, Ontario, April 10, 2013

Answer

The simple answer is that the structure of our nose has evolved this way to provide us, and our ancestors, with some sort of survival advantage. We can then make an educated guess as to what that advantage may be.

One of the important functions of our noses is to warm and humidify the air we breathe so that we don’t dry out and irritate the lungs. This happens as the air passes over the turbinates inside the nose. For the nose to do this, it takes up space. If you look at primates that live in drier, cooler climates they tend to have bigger noses. So a nose that sticks out helps with warming and humidifying air.

Why not two holes just sticking straight out? The nose also filters the air we breathe; we generally don’t do well after inhaling particles or water. Downward opening nostrils help limit unintentional inhalations. Some scientists also believe this helps humans swim.

The other important reason our nose sticks out is so that we have something to rest our glasses on!

- Dr. Theo Moraes, MD, PhD, FRCPC; Staff Respirologist, Respiratory Medicine, The Hospital for Sick Children (SickKids); Scientist-Track Investigator, Physiology & Experimental Medicine, Research Institute; Assistant Professor, Department of Paediatrics, University of Toronto.

Question

"Why do skin tags form?" A.M., Canada, March 27, 2013

Answer:

Skin tags, or acrochordons, are benign skin growths commonly seen in the skin. These are formed of collagen and blood vessels covered by thicker skin and are usually sticking out of the skin. Skin tags can be congenital (present since birth) or you can develop them later on in life. It is more common to see them in adults, but some children can develop them too. Most of the time they appear in the folds: neck, axillae (arm pit), groin, under the breasts or any other body area where the skin rubs against skin.

It is not completely clear why skin tags form, but friction or rubbing of the skin seems to play an important role in their development. This might explain why they appear in the body’s folds, where there is more friction, and why obese or overweight people are more likely to develop them, since they are more likely to have increased folds. Other theories also propose that insulin resistance or high level of growth factors can also predispose to skin tags, and this could help explain why people with diabetes and pregnant women are more likely to develop them. Sometimes, viral skin infections like warts or molluscum contagiosum, can also look like skin tags.

- Dr. Irene Lara-Corrales, MD, Paediatric Dermatologist, Staff Paediatrician, Paediatric Medicine, The Hospital for Sick Children; Assistant Professor, Department of Paediatrics, University of Toronto.

Question

"Why does your nose run when you are out in the cold?" Meghan Davidson, Age 17, Acton, Ontario, March 13, 2013

Answer

Great question, especially when there’s still snow on the ground! Believe it or not, the mucous from your nose is more than just a nuisance – it actually acts as a filter for the air entering your lungs. When it’s cold outside, the blood vessels in your nose dilate (get wider). This produces more mucous so that the cold, dry air entering through your nose is warmed and moistened. The dilated blood vessels also explain why your chilly nose may be red. As soon as you warm up, the vessels constrict (become smaller), decreasing mucous production and allowing you to put away your tissues!

- Dr. Carolyn Beck, MD, M.Sc, FRCPC; Staff Physician, Director of In-patient Unit, Paediatric Medicine, The Hospital for Sick Children; Assistant Professor, Department of Paediatrics, University of Toronto.

Question

"Why do people get headaches?" Tyson L, Age 9, Toronto, Ontario, February 27, 2013

Answer

People get headaches for all sorts of reasons, and headaches are very common. Some people are prone to getting headaches during certain times such as when they are stressed. People can also get headaches when they are sick with an infection like the flu. Other people get headaches from certain medications or even foods and beverages, such as things that have caffeine. This can happen even when it is taken away, which is why people who drink a lot of coffee can have headaches when they miss their morning cup of coffee!

Serious medical problems can also be hinted at with headaches, but this is less common. It is important to know that some headaches can be a clue that you need to go to the doctor. Examples of these clues include things such as: headaches that wake you up in the middle of the night, headaches that get progressively worse over time, headaches that occur after getting hit to the head, severe headaches that come out of the blue, or headaches associated with other symptoms like vomiting or a stiff neck. These can all be signs of something going on in the brain. If you have these or other worrying symptoms, or are not sure why you are having headaches, it is important to go and get assessed by a doctor.

- Dr. Eyal Cohen, MD, M.Sc., FRCP(C); Staff Physician, Paediatrics, Project Investigator, Child Health Evaluative Sciences, The Hospital for Sick Children; University of Toronto, Associate Professor, Paediatrics; Core Faculty, Centre for Patient Safety; Associate Professor (Cross Appointment), Institute of Health Policy, Management & Evaluation; Associate Professor (Cross Appointment), Lawrence S. Bloomberg Faculty of Nursing; McMaster University, CanChild Centre for Childhood Disability Research, Scientist.

Question

“When would we see the standardized gene therapies used to treat today's genetic diseases?” Holliday, Canada. February 13, 2013.

Answer

There is no standardized gene therapy used to treat today’s genetic diseases. Our genes are different in size and their expression patterns are not the same. For each genetic disease, scientists have to design a gene delivery vehicle, or vector, and develop a delivery method specifically for the disease. For example, a recombinant adeno-associated virus serotype 2 (rAAV2) vector has been successfully used to deliver a therapeutic gene (RPE65) to treat a form of Leber's congenital amaurosis (a rare genetic eye disease). However, it cannot be used to deliver a different therapy gene (ABCA4) to treat a different form of eye disease, called Stargardt’s disease, because the therapeutic gene is too large to be carried by the rAAV2 vector.

- Dr. Jim Hu, PhD, Senior Scientist, Physiology & Experimental Medicine, Research Institute; Professor, Department of Laboratory Medicine and Pathobiology, Paedeatrics, University of Toronto

Question

“What causes tinnitus? Is there a cure?” Sara, Age 46, Toronto, ON. January 30, 2013

Answer

Tinnitus is the perception of a sound that is self-generated, and not corresponding to any acoustic signal outside of the body. If the sound is produced in the body, for example by pulsation of blood vessels, it can often be heard by others (with a sound amplifier) and is called “objective tinnitus.” Most problematic “ringing in the ears” is generated by neuron activity in the auditory brain and is labeled as “subjective.”

There are many causes of tinnitus, the most common being the result of acoustic trauma, i.e. overexposure to loud sounds. Some tinnitus can be short-lasting; other types persist in the long term. Some tinnitus sounds can be roaring broadband noise signals; others can be very tonal and have a specific pitch.
There are many theories about the mechanisms that generate tinnitus. Some types of tinnitus, especially those occurring after noise trauma, are caused by groups of neurons that are damaged and are over active with an “injury discharge.” These might be damaged at the level of the inner ear, but will activate central auditory neurons that give rise to a sound percept. In other cases, where the tinnitus is long lasting, it is likely that groups of auditory neurons are firing spontaneously in the absence of an actual acoustic stimulus. This might be due to very local brain injury, or to a local lack of inhibitory processes that normally keep neuron activity suppressed.
There are really no good cures for most types of tinnitus; however, there are a number of ways to ease the problem. Methods include using distracting sounds to mask the tinnitus sensation, and various types of behavioural therapy can reduce anxiety and stress related to tinnitus.

- Dr. Robert Harrison, PhD, DSc, Senior Scientist, Otolaryngology, The Hospital for Sick Children; Professor, Department of Otolaryngology, Department of Physiology, University of Toronto

Question

“At what age do girls stop physically growing?” Sally, Taiwan, China. January 16, 2013

Answer

In general, girls usually stop growing at around 14-15 years of age. This happens when areas of growing bones called “growth plates” begin to close and become replaced by solid bone. It is important to mention that the time at which each person stops growing can be quite different, as some children may show changes caused by puberty or sexual maturation at different times. The changes seen in girls start with: breast development, followed by changes in hair growth, a peak growth spurt and, lastly, menstruation. While some teens may feel uncomfortable discussing the changes that are happening, it is important to bring up any concerns to your doctor so that they can make sure that growth and development are taking place normally.

- Dr. Farid Mahmud, MD, Endocrinologist, Endocrinology, The Hospital for Sick Children; Associate Scientist, Physiology & Experimental Medicine; Associate Professor, Paediatrics, University of Toronto.

Question

"Are the EEGs of autistic individuals characterized as "sleep like"? Can you describe how the autistic individual's EEG differs from that of a neurotypical EEG?” Lita, Age 51, Toronto, Ontario, January 3, 2013

Answer

The electroencephalogram (EEG) of an individual with autism is not essentially different from an awake or sleep EEG of an individual without autism. There is no dissociation between EEG and behavioral states (awake or sleep) in autistic individuals. The EEG findings are variable due to the observed diversity in autistic conditions and their degrees of severity. Importantly, the EEG in autism may reveal focal or generalized cortical discharges that are consistent with seizure activity, requiring specific clinical management. Recently in 2005, with methodology of the Canadian Task Force on Preventive Health Care, specialists in Autism and Epilepsy found “insufficient evidence to recommend for or against the use of screening EEGs in autistic patients. Given the frequency of seizure disorders in this patient population, a high index of clinical suspicion should be maintained for subtle symptoms of seizures.” [Kagan-Kushnir, Roberts SW, Snead OC 3rd. J Child Neurol. 2005 Mar;20(3):197-206].

- Dr. Miguel Cortez, MD, CSCN(C), Neurophysiologist, Neurology, Project Director, Neurosciences & Mental Health, The Hospital for Sick Children, Assistant Professor, Paediatrics, University of Toronto.

Question

“When a live donor kidney transplant is performed what happens to the adrenal gland attached to the kidney being donated? Does it remain in the donor or get transplanted along with the kidney? Or is it simply discarded?" Stephanie, Age 17, Napanee, Ontario, December 12, 2012.

Answer

Before removing a kidney from a living donor, the adrenal gland is carefully separated from the kidney and left in place so that it can continue to function in the donor.

The adrenal glands (there are two) are small endocrine organs that produce a number of different hormones. These hormones are important in regulating a variety of body systems including metabolic rate, cardiovascular function (heart rate and blood pressure) and renal function (fluid and electrolyte handling). A number of serious medical problems can result from improper functioning of the adrenal glands.

- Dr. Anand Ghanekar, MD, PhD, FRCSC, Division of General Surgery, The Hospital for Sick Children, University Health Network, Affiliate Scientist, Toronto General Research Institute. University of Toronto Faculty of Medicine profile

Question

“Why do all babies have blue eyes?” Christine, Age 23, Toronto, Ontario, November 28, 2012

Answer

To answer that question it is first good to review some facts about the eye. The colour of a baby's eye depends on a muscle in the eye called the iris. This muscle has a hole in the middle which appears black (no matter what colour your eyes are) and is called the pupil. The pupil allows light to get in the eye for us to see and the iris controls how much light gets in.

So, in fact the majority of children in the world (think Africa, Asia, South America for example) are almost always born with brown eyes! But you are right –many children of Caucasian background are born with light-coloured eyes. I say light-coloured as many are grey, blue, green, hazel or a mixture of these colours. Interestingly, in some children the colour of the eye gets darker as they grow older. This is usually because the amount of pigment can increase with time.

- Kamiar Mireskandari, MBChB, FRCSEd, FRCOphth, PhD, Staff Ophthalmologist and Assistant Professor, Department of Ophthalmology and Visual Sciences

Question

“Can you play in a punk rock band when you are pregnant? Will doing so affect the baby's hearing or affect it in other ways? Does this change further in to the pregnancy?” Julie, 27, Barrie, Ontario, November 14, 2012

Answer

There are no studies on the effects of playing in a punk rock band on the developing fetus. The available information on noise exposure in pregnancy comes from studies of occupational exposure to noise, such as aircraft noise, road and rail traffic noise etc. A recent review on health effects of chronic noise exposure in pregnancy and childhood concluded that chronic noise exposure during pregnancy was not associated with low birth weight, preterm birth, congenital anomalies and perinatal and neonatal death.

- Anna Pupco, MD, Gideon Koren, MD, FABMT, FRCPC, The Motherisk Program

Question

“Why is medicine bad for pregnant women?” Elena, Age 13, Mississauga, Ontario, October 31, 2012

Answer

It is a common misconception that all medication is bad for pregnant women. With every pregnancy there is a risk that the child could develop congenital malformations. This risk is estimated to be between one and three per cent. When we talk about medications causing birth defects we are talking of an increase of this baseline risk. Most medications do not increase this risk.

We also need to be aware of the fact that many women need their medication to remain healthy enough to become pregnant and to carry the pregnancy to term. For many of those women, stopping the medication would cause more adverse effects to her and her baby than the medication itself.

However, a small number of medications are indeed known to increase the risk for congenital malformations. Even then the outcome depends on many factors including the timing of exposure during pregnancy.

Women treated for chronic conditions are usually advised to talk to their physician when considering pregnancy, in order to plan their treatment before and during pregnancy to achieve optimal outcomes for themselves and their child.

- Anna Pupco, MD, Gideon Koren, MD, FABMT, FRCPC, The Motherisk Program

Question

“What kind of microscope do you need to be able to see different species of microorganisms, like different tardigrade species for example? ” Abrar, Age 16, Charlotte, USA. October 16, 2012

Answer

There are many types of microscopes you can use to study microorganisms. Light microscopes are quick and easy to use, and provide sufficient magnification (usually 10x-100x) to see most types of microorganisms. Light microscopes can also be used in combination with specific stains that help to identify microorganisms and study their activities. For example, you can stain Salmonella with a specific antibody and use a light microscope to see where the bacteria are located within our cells during an infection.

Electron microscopes are less practical and take more time to use, but provide a more detailed view of microorganisms since they have a much higher magnification (up to 2000x). Many of the textbook pictures of microorganisms come from electron microscopes since they give stunning detail.

One of the limits of all microscopes is that they don’t always differentiate between species of microorganisms. If you were to just look at E. coli and Salmonella without any special staining method, you could not be able to differentiate these two from each other. They just look like little rods. In fact, many bacteria look the same as these two bacteria. For this reason we often rely on other methods (such as DNA sequencing) to confirm the identity of a microorganism when we look at a new sample of bacteria for the first time.

- Dr. John Brumell, PhD, Senior Scientist, Cell Biology Program, The Hospital for Sick Children, Professor, Department of Molecular Genetics, University of Toronto

Question

“Why do my leg muscles twitch after working out?” Lisa, Age 38, Toronto, Canada. October 3, 2012

Answer

The involuntary muscle twitches, or ‘benign fasciculations’ that you are experiencing after workouts are a common after-effect of exercise, and have numerous causes. Every muscle movement is the result of thousands of tiny muscle fibers contracting and relaxing, which use energy stored in the muscle. Glycogen metabolism primarily fuels this process in the so-called ‘fast-twitch’ muscle fibers responsible for high levels of power output and speed. Therefore, when you deplete your glycogen stores you reduce the ability of the muscle fibers to contract and relax properly, and therefore experience a muscle spasm.

Muscle twitches after exercise could also be caused by sweat-induced loss of electrolytes such as sodium, chloride, and potassium. These molecules help the body’s cells transmit electrical signals, and when their concentrations are reduced this can result in improper nerve signaling. Magnesium helps the muscle fiber to relax following a contraction; therefore proper hydration with an electrolyte-containing beverage can help ward off spasms.

Proper fluid replenishment right after exercise is crucial to ward off muscle twitches. This is because dehydration can reduce your blood volume, which will limit the amount of oxygen reaching your muscles. A general rule of thumb is to replenish with 1 litre for every kilogram of body weight lost due to sweating during exercise.

- Dr. Greg Wells, PhD Associate Scientist, Physiology & Experimental Medicine, Assistant Professor, Faculty of Kinesiology and Physical Education, University of Toronto.

- Jessica Caterini, B.Sc

Question

“How does one develop a plantar wart? What are the most effective forms of treatment and prevention?” Tami, Toronto, Canada. September 19, 2012

Answer

Plantar warts are viral infections of the skin. The same as warts elsewhere in the body, they are caused by Human Papillomavirus (HPV). The virus leads to a rapid growth of the skin, and this is why you get that bumpy, rough skin when this infection develops. When these appear in the plantar surface of the feet, they are called plantar warts, and these make up about 30 per cent of all warts.

It is important to know these are completely benign growths. Commonly warts are asymptomatic, but when you have a plantar wart it can be painful just because of its location. Plantar warts are typically found on the pressure points on the bottom of the feet, and when you walk the pressure the wart has on the skin might cause discomfort and pain.

The virus that leads to warts can easily spread from person to person by touching or sharing objects such as towels. . You can take care of your skin by moisturizing and preventing breaks in the skin that could allow the virus in. It also helps to keep your hands and feet dry, since the virus likes moist conditions. Another way of reducing the risk of getting this virus is by using water shoes when you go to a public pool or using flip flops when you shower in public showers. If you have a wart, you can also keep it covered when you are in public places to prevent others from getting the virus.

Treating warts is not always necessary, because these may go away on their own. There is no treatment available that kills the virus to make the warts disappear. Most treatments kill the cells that contain the virus and stimulate the immune system to react towards the virus and make it go away. Common treatments include duct tape, salicylic acid or lactic acid, liquid nitrogen, imiquimod and vitamin A derivatives, among others.

- Dr. Irene Lara-Corrales, MD, Staff Paediatric Dermatologist , Paediatric Medicine, Project Investigator, Child Health Evaluative Sciences, The Hospital for Sick Children, Assistant Professor, Department of Paediatrics, University of Toronto

Question

“Why is it that the cases of auto immune diseases like Kawasaki Disease are so difficult to trace? Even if it is an extremely common disease affecting so many related in the world. Also, why can patients contract this disease later in life ex. eight years of age when normal is one to two years?" Michael, Canada. August 21, 2012.

Answer

Kawasaki's disease (KD) is a vigorous autoimmune reaction causing inflammation of blood vessels, skin and mouth, and in a minority of cases there can be serious effects on the heart. Like other autoimmune diseases, KD is caused by multiple factors including genetic variations and environmental triggers like viral infections. In some cases KD has been associated with specific viral infections which can occur at different times in childhood. It is often hard to trace these infections as causes of KD because the viruses are very common and thousands of kids with these viral infections don't get KD.

- Dr. Jayne Danska, PhD, Senior Scientist, Genetics and Genome Biology, Professor, Medical Biophysics, Institute of Medical Sciences, Faculty of Immunology, University of Toronto

Question

“Will there ever be a cure for genetic heart muscle disease? (ARVC) And do you think the artificial heart will ever be a realistic medical device? (Implanted inside the body, motors to regulate blood flow)” Michael, Canada. August 7, 2012.

Answer

These are two interesting questions. The problem for curing genetic diseases is that it is difficult to change the genetic material. Several attempts have been made to fix the genes through gene therapy, but so far this has not been very successful. One of the problems is that in almost every family, different mutations are present, which make it difficult to develop a cure that works for everyone. Recent insight into the genes that cause different types of heart muscle diseases certainly help to better explain the mechanisms that are involved in the disease process. This hopefully will help to design better therapies for heart muscle diseases in the future.

Regarding the question on artificial hearts, there has been significant progress during the last few years as several types of artificial heart pumps have been developed and are currently being used in patients. These devices are used to help patients with very severe heart muscle disease while they are on a waiting list for heart transplantation. However, there are still a lot of problems that need to be addressed with artificial hearts.

- Dr. Luc Mertens, MD, PhD, Cardiologist, Section Head Echocardiography, Associate Professor, The University of Toronto

Question

“How does one acquire the JC Virus? If possible, how does it enter our body (i.e. what receptors are activated)? What is being transferred between the cells?" Dharshana Sivananthan, Age 18, Scarborough, ON. July 24, 2012

Answer

JC virus is a double-stranded DNA virus that belongs to a family of viruses called polyomaviruses. It is very common and most people are infected as children or adolescents. The virus is thought to infect either the tonsils or the gastrointestinal tract potentially through contaminated water, although this is not known for sure. Initial infection is usually asymptomatic and the virus remains latent in the gastrointestinal tract. It can also infect the tubular epithelial cells in the kidney and be excreted in urine.

If a person who has been infected previously becomes immune deficient due to another disease (such as AIDS) or treatment with immunosuppressants, the virus can reactivate and cause a disease of the central nervous system called progressive multifocal leukoencephalopathy (PML) by destroying brain cells called oligodendrocytes. There is evidence that the JC virus may also play a role in colorectal cancer, however, this has not been definitively proven.

- Dr. Astrid Petrich, PhD, RMCCM, Clinical Microbiologist, Paediatric Laboratory Medicine

Question

“Is there a pharmacology interaction between methotrexate and vitamin C?” Francisca, Age 24, Santiago, Chile. July 10, 2012

Answer

Methotrexate and vitamin C each have a different mechanism of action. As a folate antagonist, methotrexate inhibits the synthesis of certain nucleotides. This interferes with DNA production, repair and cellular replication. Vitamin C is water-soluble and essential for the formation of collagen and intercellular material. It also influences the formation of hemoglobin, erythrocyte maturation, and certain immunologic and biochemical reactions in the body. There is no evidence that methotrexate and vitamin C interfere with each other’s absorption, distribution or elimination, meaning there are no interactions between them.

- Dr. Gideon Koren, MD, FABMT, FRCPC, Director, The Motherisk Program, Senior Scientist, Child Health Evaluative Sciences, Professor of Pediatrics, Pharmacology, Pharmacy, Medicine and Genetics, University of Toronto

Question

“When will someone find a cure for anaphylactic food allergies? Has anyone tried to block the IgE antibodies? Or use stem cells to cure the allergies?” Jyoti Parmar, Canada. June 26, 2012

Answer

Thank you for your question. There is great interest in preventing anaphylaxis to food. The current standard of care, avoiding the food and carrying an epinephrine auto-injector, is not ideal.

There are many approaches currently being investigated for people with anaphylactic food allergies. Regular immunotherapy injections of the unmodified protein used for hay fever pollen allergies have been shown to be too dangerous for food, so different approaches are being sought out. There are food allergy immunotherapy studies in pre-clinical and clinical trials. These approaches involve giving increasing amounts of the food over time either by mouth, under the tongue or through the skin. Peptide immunotherapy, which uses a modified version of the food, is also being studied.

Other treatments being investigated include studies in animals that attach a part of a food protein to white blood cells to try to reduce the allergic reaction. There is a Chinese herbal treatment (FAHF-2) that has just started a clinical trial in Chicago. There is interest in using parts of parasites to modify the allergic reaction based on the idea that the prevalence of allergies increases with cleanliness.

There are also trials involving anti-IgE molecules either used on their own or with immunotherapy. One of these drugs, omalizumab, is available to treat asthma but is not currently approved for use with food allergies.

There are several unanswered questions about these approaches. They include who the best candidates are for these possible treatments, what regimens should be used, how long treatment is needed, if the treatment will result in a true cure or a temporary reduction in symptoms, and what the safest way to balance risk and reward is. Therefore, they are all considered to be experimental at this time.

Stem cells can profoundly change the immune system. There are genetic conditions such as the Omenn's syndrome and IPEX disease that have some features similar to allergies. These can be treated with hematopoietic stem cell transplants, but the current risks of the procedure make it inappropriate for food allergies.

There are no treatments considered ready for widespread clinical use, but given that many of these trials are already at the human stage, this is a time of great hope for people living with food allergies and the families that support them.

- Dr. Julia Upton, MD, RCPS (C), Clinical Immunology and Allergy, Staff Physician, Division of Clinical Immunology and Allergy; Lecturer, University of Toronto

Question

“How are twin babies produced if only one sperm cell can enter the egg?” Ria, Canada. June 12, 2012

Answer

Fertilization is a process that causes a chemical reaction, blocking further sperm from entering the egg. Successful fertilization of an egg produces a single embryo (zygote). So what does this have to do with twins? The first thing to remember is that there are two types of twins. If you have ever wondered how a boy and a girl from the same family with the same birthday get away with calling themselves twins, it is because they came from two different sperm which fertilized two different eggs at around the same time. These twins develop together inside the mother and end up looking no more alike than any two siblings of a similar age would. These twins are called fraternal or dizygotic twins (di=two, zygote-embryo)

Now, how can you get two identical twins from one egg and one sperm? The simple answer is that after fertilization, the embryo can split into two. This occurs long before the embryo looks anything like a baby and is made up of relatively few cells. After the embryo splits, each half can develop into a fully formed baby. This gives rise to what is called identical or monozygotic twins (mono=one, zygote=embryo). While they are not strictly identical, they may look that way because they came from the same sperm and egg. Identical twins of all ages have contributed to our understanding of how our genes and environment work together to make us who we are.

- Michael Wilson, PhD, Scientist, Genetics and Genome Biology

Question

"Are we getting closer to developing new treatments for childhood cancers?" Jenn F, Age 26, Colborne, ON. May 29, 2012

Answer

New treatments for childhood cancers are constantly being developed. Over the last decade, paediatric oncologists (doctors who specialize in the treatment of childhood cancers) have been incorporating new drugs into more conventional recipes of chemotherapy. These new drugs have some interesting properties. First, they are designed to target cancer cells more precisely than conventional chemotherapy drugs. Second, many of these drugs come in the form of tablets or pills and can be given at home and do not require hospitalization. As new drugs are being developed, they are tested in large-scale international clinical trials to determine both their safety and effectiveness. Although this process may take several years to complete, there continues to be improvements in the outcomes of children with cancer with the addition of these new treatment approaches.

- David Malkin, MD, FRCP(C), FAAP, Senior Scientist, Genetics & Genome Biology, Director, Cancer Genetics Program, Haematology/Oncology, SickKids; Professor, Department of Paediatrics and Medical Biophysics, School of Graduate Studies, University of Toronto

Question

“How does croup start?” Hana, Age 9, Allenby Elementary School, Toronto, ON. May 15, 2012

Answer

The medical term for croup is laryngotracheobronchitis. This is a childhood illness caused by a common viral infection. The common cause of croup is the parainfluenza. This virus is spread from person to person through respiratory droplets (for example, from a cough or sneeze). The virus settles in the upper airways, including the larynx (the voice box) and the trachea (windpipe), causing swelling and inflammation. This leads to breathing difficulty, a hoarse voice, and a ‘barking’ cough. The swelling usually gets better on its own as the virus disappears. The child returns to good health within three to seven days. Most people have an infection with the parainfluenza virus during their childhood, and most cases of croup are mild.

- Dr. Patricia Parkin, MD, FRCPC, Senior Associate Scientist, Child Health Evaluative Sciences, Division of Paediatric Medicine and the Paediatric Outcomes Research Team (PORT), Professor, Departments of Paediatrics and Health Policy, Management and Evaluation, University of Toronto

Question

"What is your brain made of?" Harrison, Age 7, Whitby, ON. May 1, 2012

Answer

Firstly, most of your brain is made of water and fat. But those are just the main materials of a very complex organ. If you could look into a brain with a very big magnifying glass, you would find that it is composed of many little things scientists call neurons that look a lot like trees. These neurons have many branches, like a tree, and the neurons communicate with each other through these branches using electricity. Each neuron is responsible for many different things, so it is very important that they communicate with each other. Neurons in the brain control everything from the heartbeat to breathing to the movement of the body.

Neurons also act as storage for memories and fantasies. Neurons are living cells anc can have a great impact on the body if they are not healthy. For example, diseases such as Parkinson's and Alzheimer's dises are caused by damaged or dying neurons. Though there are many factors that contribute to disease, it's important to keep your brain and your neurons healthy! The best way to keep your brain healthy is through exercise, eating healthy food, such as fruits and veggies, and avoiding things that are bad for you brain, such as smoking cigarettes and drinking alcohol.

- Alonso Martinez-Canabal, M.Sc, Biology, PhD Candidate, Dr. Paul Frankland's Lab, University of Toronto
- Dr. Paul Frankland, PhD, Senior Scientist, Neurosciences & Mental Health, Associate Professor, Physiology, University of Toronto.

Question

“Why is your blood red?” Luke, Age 9, Allenby Elementary School, Toronto, ON. April 19, 2012

Answer

Your blood is red because it contains tiny red cells called red blood cells. These red blood cells pick up oxygen from the lungs and take it to all parts of the body. Oxygen is very important for the body to survive. Red blood cells also carry carbon dioxide that is produced by the body. The red blood cells then carry the carbon dioxide to the lungs where it is breathed out. Red blood cells contain a protein called hemoglobin which is important for carrying the oxygen. The iron in hemoglobin gives red blood cells its red colour, which causes blood to be red. People that have low levels of healthy red blood cells have a disease called anemia.

- Dr. Chetan Tailor, PhD, Scientist, Cell Biology, Assistant Professor, Department of Molecular Genetics, University of Toronto

Question

“How does your heart beat?” Jayden A, Age 9, Allenby Elementary School, Toronto, ON. April 4, 2012

Answer

The heart is a special kind of muscle. When the heart muscle squeezes, it pushes blood through the blood vessels. It then relaxes, and fills up with blood again as it gets ready for another squeeze.

The heart has two sides, and two chambers on each side. When the heart beats, the top chamber on each side squeezes together and pushes the blood into the bottom chambers. After the bottom chambers fill up, they squeeze together to push blood out of the heart. From the right side heart, blood gets pushed into the lungs, while the aorta (a big artery) directs the fresh blood from the left side out into your whole body. The heart has an electrical system in which makes sure that the squeezing happens in the right order. The electrical system also sets how fast the heart beats, so that it beats slower or fewer times when you are sleeping, and beats faster and harder when you are active.

It is important to take good care of your heart, making sure it is a strong and healthy muscle: always eat lots of fruits and vegetables, and try to keep the junk food and sugary drinks to a minimum. Try to keep the amount of time you spend on the computer, watching TV, or playing video games to no more than an hour a day. It is important that you get enough exercise each day - one hour every day, and try to get more than that on weekends. Most importantly, never smoke cigarettes. Taking good care of your heart is one way that you can make sure that your whole body stays fit and healthy.

- Dr. Brian W. McCrindle, MD, MPH, FRCP(C), FACC, Senior Scientist, Cardiology, Child Health Evaluative Services, Professor, Paediatrics, University of Toronto

Question

Why do I breathe a lot and struggle a bit when I play soccer or swim for a short time?” Emma C, Age 9, Allenby Elementary School, Toronto, ON. March 27, 2012

Answer

When we exercise our bodies have to burn the foods we eat for fuel. It's just like a car burns gas for fuel. When you do harder exercises, like sprinting for the ball in soccer or swimming a few laps in the pool, your body will burn sugar to give it the energy it needs to help your muscles work. This causes you to feel a bit tired because it’s hard for your muscles to work that hard. Your body needs oxygen from the air to help it create energy. Once that energy is created, your body needs to get rid of the carbon dioxide that your muscles produce when you exercise and this causes you to breathe harder. The great and amazing thing about the body is that it changes quickly to get stronger and faster, so if you keep exercising (like playing soccer or swimming regularly) you won't be as tired and it will be easier to breathe when you run and swim. So keep it up!!!

- Dr. Greg Wells, PhD, Associate Scientist, Physiology & Experimental Medicine, Assistant Professor, Faculty of Kinesiology and Physical Education, University of Toronto. www.drgregwells.com

Question

“In 2006, there was a study on capsaicin injections that "woke up" beta cells in diabetic mice. It says that Drs. Hans-Michael Dosch and Michael Salter worked on the study. Has there been any new research on humans? Were the results faulty? What happened to the study?” Joe, U.S., March 20, 2012

Answer

We have spent the past three years expanding our research on neuropeptide deficiency in Type 1 diabetes, including extensive preclinical studies in patients. We are now in the process of developing a clinical trial series to translate our discoveries to human Type 1 diabetes and are now in contact with Health Canada to submit documents for regulatory approvals of these trials.

- Dr. Hans-Michael Dosch, PhD, MD, Senior Scientist, Neurosciences & Mental Health, Professor, Paediatrics and Immunology, University of Toronto

Question

“How much ‘snot’ can a human body produce? Can you run out/dry up?” Fran, Age 53, Canada, March 6, 2012

Answer

The human body is remarkable in that it can produce approximately 1-2 litres of mucus each day. For most people, mucus is helpful because it keeps the lining of your nose, mouth and throat wet, meaning it prevents bacteria and viruses from entering the body, and it kills and washes away bacteria. You asked if it can run out or dry up – the ultimate question is - why are you asking?

If you have too much mucus and it is bothersome for you, then there are things you can do to decrease it. Some of these may include increasing your water intake to thin out the mucus, quitting smoking if you smoke, salt water rinses, removing allergens from your home, and over-the-counter and prescription medications. If you don’t have enough mucous, then talk to your doctor about medications that can keep your nose moist (these are called lubricants). If your mucus is not bothering you and you’re simply worried that it will eventually run out – don’t worry – it will likely never happen…and besides, anxiety only makes you produce more mucus! If you have concerns about your mucus, it is best to speak to your doctor.

- Dr. Evan Propst, MD, FRCSC, M.Sc, Project Investigator, Developmental & Stem Cell Biology, Otolaryngologist, The Hospital for Sick Children, Assistant Professor, Otolaryngology, University of Toronto.

Question

"Why do we get moles?" Juan, Age 36, Markham, ON. February 21, 2012

Answer

Our skin is made up of many types of cells. Among these are melanocytes- cells that contain a pigment called melanin. Melanin contributes to the color of our skin, but also helps to prevent damage from sun exposure. Moles, or melanocytic nevi are benign growths that occur when clusters of melanocytes multiply in a localized area. They often appear as small round brown marks, but can be pink, flesh colored, tan or even black, and they can be flat or raised. They may also have hairs protruding from them. There are many types of moles, but we commonly divide them into congenital (present at birth), and acquired.

Congenital nevi are usually present at birth, but may become apparent a few months later. These are usually less than 1.5 cm. in diameter, but rarely can be more than 20 cm. Acquired nevi are very common. They occur early in childhood, increase in number until about 30 years of age, and then disappear slowly with time. Lighter skinned individuals are more likely to develop moles. Sunburns or prolonged sun exposure in childhood also increases the risk of mole formation. In addition, a family history of moles can add to the risk increase.

People with large moles (greater than 20 cm. diameter), or numerous moles are at increased risk of developing a skin cancer called melanoma, so it's important to be familiar with characteristics that make a mole worrisome. We use the ABCDE rule. Moles that show Asymmetry, irregular Borders, varied Color, large (greater than 6mm diameter) or increasing Diameter, or are Evolving or changing, should be checked by a doctor. Using sunscreen regularly during periods of sun exposure has been shown to decrease the number of moles that develop, as well as the risk of skin cancers. This is an easy thing we can all do to keep our skin healthy!

- Harkamal K. Randhawa, MD, B.Sc, BA, FRCPC, FAAP, Clinical Fellow, Paediatric Dermatology, SickKids, University of Toronto

- Elena Pope, MD, M.Sc, FRCPC, Project Investigator, Paediatric Medicine, Head, Dermatology, SickKids, Associate Professor, Paediatrics, University of Toronto.

Question

"Is there a cure for juvenile rheumatoid arthritis?" Vicky M, Age 12, Canada, February 7, 2012

Answer

This is an excellent question with a somewhat complicated answer. Unfortunately there is no single cure for all types of arthritis in children. However, modern treatments are usually very effective in controlling childhood arthritis, often taking away the symptoms completely. Some types of arthritis respond quickly and extremely well to a single injection of medication into the effected joints. This can be done very easily and painlessly when kids are given a sedative (medicine that puts you to sleep). Other types of arthritis may require medications to be taken on a regular basis to stop the symptoms.

- Dr. Rayfel Scneider, MD, FRCPC, Project investigator, Rheumatology, Associate Chair, Education, Staff Rheumatologist, Rheumatology, SickKids and Associate Professor, Paediatrics, University of Toronto

Question

“I'd like to know why coughs are ALWAYS so much worse in the evening? Does it have to do with the moon and stars?” John, Age 42, Toronto, ON., January 25, 2012

Answer

It does if you are lying down to see the moon and stars!

A cough is your body’s way of pushing something irritating out of your throat or lungs, and there are many reasons for you to cough, such as: asthma and allergic rhinitis (hay fever), the common cold, gastroesophageal reflux disease (heartburn) and new evidence that suggests sleep apnea may also cause coughing.

Coughing is one of the most common symptoms of asthma, and nighttime cough suggests that the asthma is not well controlled. Asthma gets worse at night for a few reasons. Airways narrow a bit at night because of the normal changes in the levels of certain hormones making you more likely to experience asthma symptoms, like a cough. Also, your pillow could be full of dust mites, a very common asthma trigger, which means you are breathing the dust mites all night long.

With allergic rhinitis and the common cold, when you lie down, the mucus will drain into your lungs instead of your nose, and this leads to more coughing.

Another cause of nighttime cough is gastroesophageal reflux disease (GERD). GERD causes stomach acid to travel up the esophagus and cause inflammation. If someone experiences GERD for a while they begin to develop inflammation in the lungs which leads to increased cough. In addition, because of gravity, it is easier for acid to reflux and stay in the esophagus when you are lying down.

Finally, sleep apnea, abnormal pauses in breathing during sleep, can also contribute to nighttime cough either directly or by making asthma and GERD worse.

- Dr. Reshma Amin, MD, MSc, FRCPC, Associate Scientist, Child Health Evaluative Sciences and Staff Respirologist, Respiratory Medicine, SickKids; Assistant Professor, Department of Paediatrics, University of Toronto

Question

"How many kids come to SickKids because of peanut allergies?" Lisa, Scarborough, ON., January 10, 2012

Answer

Thanks for your question, Lisa. Emergency visits to SickKids for allergies are common, and peanuts, nuts in general, are a common food that children can react to. Reactions can include an itchy rash, vomiting or more worrisome symptoms like problems breathing and mouth swelling. The emergency department at SickKids saw more than 800 children in the last year with allergy-related problems, but fortunately, less than 5 per cent of them were for the most serious reactions.

- Dr. Stephen Porter, MD, MPH, MSc, Senior Associate Scientist, Child Health Evaluative Sciences and Division Head, Emergency Medicine; Associate Professor, Paediatrics, University of Toronto.

Question

What causes snoring? Is obesity related to snoring? Dua, Age 40, Toronto, ON., December 13, 2011

Answer

Great question Dua! Snoring is a vibratory sound that comes from your upper airway breathing tube when the passage of air is obstructed. Snoring can also be a sign of sleep apnea where there are pauses in breathing while sleeping. Obesity is strongly related to snoring and up to half of all children with obesity will snore. Also, obesity is a strong risk factor for sleep apnea.

- Dr. Indra Narang, MEDSCI, MBBCH, FRCPCH, MD, Associate Scientist, Physiology & Experimental Medicine, Director of Sleep Medicine and Staff Respirologist, Respiratory Medicine, SickKids; Assistant Professor, Paediatrics, University of Toronto

Question

I often feel my heart beat in places other than my chest. For example: I'm lying on my front during yoga and all I can think about is the booming inside my abdomen. Is this normal? Katrina, Age 17, Toronto, ON., November 29, 2011

Answer

When your heart pumps, the blood is pushed in a wave (a pulse) through your arteries and delivered to the rest of the body. Sometimes that pulse can be felt in other parts of the body, particularly in the larger arteries such as the aorta which runs through your chest and abdomen. Doctors can use this to check the rate and strength of your heart by feeling for a pulse, frequently in the wrist, neck, groin or ankle

- Dr. Elizabeth A. Stephenson, MD, Project Investigator, Research Institute, Clinician-Teacher and Staff Cardiologist, Cardiology, SickKids; Assistant Professor, Paediatrics, University of Toronto

Question

"Why do we get yeast in our body and how does it affect us?" Ethan, Age 10, Mississauga ON., November 4, 2011

Answer

That is a good question because we have yeast all around us all the time. Generally, yeast is good for us and there is even yeast on our skin and in our guts that helps us absorb nutrients in our food and prevents us from getting sick.

So, to answer your question, we encounter yeast all the time and it gets into our bodies from the food we eat or through cuts in our skin. Most of the yeast that enters our bodies is good for us, but sometimes we encounter bad yeast that can make us sick. There are scientists trying to figure out how the bad yeast causes disease and trying to find new ways to stop the bad yeast with new medicine. Maybe you can work on this challenge someday too!

- John Brumell, PhD, Senior Scientist, Cell Biology, Associate Professor, Institute of Medical Science, Department of Molecular Genetics, University of Toronto.

Question

“Is there a cure for autism?” Krishasayi, Age 13, Markham ON., October 18, 2011

Answer

Autism is a hard disorder to understand because there are many different pathways in the brain that are wired differently from other people. Different treatments can help with: how to talk, how to learn, how to socialize (this is hard) and how to understand and share in other people's emotional experiences. But, this does not lead to a cure, and there are many new challenges that come up as children with autism get older.

There are many challenges for family members of people with autism, but there is also much joy that comes to families when gains are made. So, there is no cure but there are many treatments. The earlier you begin working with autism, the better the outcomes, and the more chance that the person with autism can grow up to be a happy and independent adult.

- Dr. Wendy Roberts, MD, FRCP(C), Project Director, Neurosciences & Mental Health and Co-director, Autism Research Unit, SickKids; Professor of Paediatrics, Dept. of Paediatrics, University of Toronto.

Question

“Why are some kids born with eczema?” Sabrina, Age 8, Mississauga ON., October 3, 2011

Answer

This is an interesting question because it does not have a clear answer. Although we now understand more about eczema, we still do not fully understand why it happens. We know that there seems to be a genetic component to the disease. This means that if one of your parents has eczema, you are more likely to have it and if both your parents have it, you are even more likely to develop it. There is another group of patients with eczema that do not have any genetic link to the disease. There are also environmental factors that might trigger the eczema: heat, dry weather and even substances that irritate the skin. We also know that many cells from our immune system have been identified in the skin of patients with eczema, and are thought to also be involved in causing eczema. So, we believe that eczema is the result of complicated interactions between a genetic predisposition, the environment and different cells in your skin, but the exact mechanisms that lead to eczema are still not completely understood.

Question

"How many litres of blood does the heart pump?" Rebecca, 11, Toronto, ON., September 20, 2011

Answer

The normal adult heart pumps about five litres per minute. In a newborn, it pumps a little less than a litre per minute.

- Dr. Seema Mital, MD, FACC, FAHA, FRCP(C), Staff Cardiologist, Cardiology, SickKids, Associate Scientist, Genetics & Genome Biology, Research Institute, Associate Professor, Pediatrics and Roma and Marvin Auerback Professor of Developmental Biology, Faculty of Medicine, University of Toronto

Question

"Is it possible to have an allergic reaction to a flu shot?" Kate, Age 23, Amherstburg, ON., September 7, 2011

Answer

Allergic reactions to the flu shot are rare as the virus is purified before use in vaccines. However, the flu virus used in the vaccine is usually grown on chicken eggs and trace amounts of chicken egg may be present in the vaccine. Therefore, people with chicken egg allergies could have a reaction to the flu shot and these individuals should be monitored by their doctor after the vaccination to ensure that there are no adverse reactions. Usually, under normal doses the flu shot, on its own, is not known to cause allergic reactions.

- Dr. Nades Palaniyar, MSc., PhD. Scientist, Physiology & Experimental Medicine, SickKids and Assistant Professor, Laboratory Medicine & Pathobiology, University of Toronto

Question

"Why do cleft lips and cleft palates occur?" Kaitlyn, Canada, August 23., 2011

Answer

Cleft lip, and cleft palate, occurs because of interruptions in the program of development in the lip and palate. When people are still very small (only a few weeks gestation in the mother's uterus), a sequence of genes is needed to be activated in the proper order for lip development to occur. If this sequence is altered then clefting of the lip may occur. In addition to clefts of the lip, clefts of the gum and of the underlying bone and tooth buds may occur too. The nose is also affected.

In cleft palate, another gene sequence must be activated during development. In addition, mechanical forces can also play a role in producing a cleft palate. In clefts of the palate, sometimes only the muscle of the palate is affected, and sometimes the bone and overlying soft tissue is clefted too.

- Dr. Gregory H. Borschel, MD, FACS, FAPP, Associate Scientist, Physiology & Experimental Medicine and Surgeon, Plastic Surgery, SickKids; Assistant Professor, Departments of Surgery and Biomaterials, and Biomedical Engineering, University of Toronto

Question

"Does coffee stunt your growth or is that just a myth?” Gabrielle, Age 15, Woodslee, ON., August 10, 2011

Answer

It is a myth that coffee stunts your growth! Coffee does have very specific effects on your body – in fact, it is the caffeine in the coffee that has these effects. Caffeine can make your heart race, can make you jittery and for many people it can prevent you from falling asleep at night. But, one thing that it does not do is stunt your growth.

- Dr. Stanley Zlotkin OC, MD, PhD, FRCP (C) Senior Scientist, Child Health Evaluative Sciences, Vice-President, Medical and Academic Affairs, The Hospital for Sick Children and Professor of Paediatrics and Nutritional Sciences, University of Toronto.

Question

"How come you have to drink so much water before you get an ultrasound?" Livija, Age 12, July 27, 2011

Answer

Some types of ultrasound examinations, such as the ones for evaluation of the pelvis and kidneys and bladder, require that the patient drinks enough fluid to fulfill the urinary bladder. In this type of examination the urinary bladder acts as a "window" that enables the sonographer to obtain images from the uterus and ovaries (in case of girls), prostate and seminal vesicles (in case of boys) or bladder and distended ureters (in girls or boys). The patient must finish two or three glasses of water (400-500 ml) at least 30 minutes prior to the procedure. The bladder must be full for the examination, however, if the patient feels uncomfortable and still needs to wait for his/her examination he/she can eliminate part (not everything) of the content of the bladder prior to the examination so that the examination is not painful.

- Dr. Andrea Doria, MD, PhD, MSc, Scientist, Physiology & Experimental Medicine, Clinician Scientist/Staff Radiologist, Diagnostic Imaging, The Hospital for Sick Children, Co-Director of Research (Fellowship Program) and Associate Professor, Medical Imaging, University of Toronto

Question

"When you clap your hands why do germs not get squished?" Logan, Age 7, Orangeville ON., July 13, 2011

Answer

Germs are very tiny. To be able to see bacteria, we need to use a microscope that magnifies the bacteria a hundred to a thousand times larger than their actual size. Other germs on our hands are viruses, which are even smaller than bacteria. To see them we need to use a special powerful microscope called an electron microscope that can magnify the virus up to 500,000 times its actual size. So the reason germs don’t get squished when you clap your hands is because they are so small that they don’t even feel the clap. They live in cracks and folds on the skin and are protected by their small size from the effect of a clap. If you want to physically burst open bacteria, you need to use a method we call sonication, which breaks open the bacteria by blasting sound waves at them.

- Dr. Susan Richardson, MD, FRCP(C), Senior Associate Scientist, Physiology & Experimental Medicine and Head, Microbiology, SickKids; Associate Professor, Laboratory Medicine & Pathobiology, University of Toronto

Question

“How do finger and toe nails grow?” Sophie, Age 15, Essex ON., June 28, 2011

Answer

Nails help to protect our toes and fingertips. They also help with the function of the hand by helping us grab things. To understand nail growth, it is important to first understand certain parts of the nail. The area where the nail is attached to the finger is called the nail bed. The skin area, were the nail comes out of the skin, is the root of the nail and it is called the cuticle. Under the cuticle, hidden under the skin, is the nail matrix. In this same area you see a half moon – a whitish structure called the lunula that is a projection of the nail matrix.

Nail growth takes place under the skin at the base of the nail where the lunula is found. This area, where the nail grows, is referred to as the growth plate or matrix. This area is made up of epidermal cells (skin cells). This is where they multiply and mature. New cells push older cells to the surface and as they do, the cells fill up with keratin and die. Keratin is a protein that not only makes up nails but also hair and the outer layer of our skin. Once this takes place, the nail becomes hard and extends to the tip of the finger (where we cut them). Since these cells are already dead, it doesn’t hurt when we cut our nails.

The finger nails grow faster than the toe nails. In average finger nails grow between 0.5 to 1.2 mm per week. In childhood, nails grow faster than in adult life.

Question

"Why did my grandpa’s hair turn grey?" Caleb, Age 6, Toronto ON., June 14, 2011

Answer

Did you know that as we age, our hair is not grey or white in colour? In fact, the hair is actually clear due to the loss of pigmentation.

Our body contains specialized cells called melanocytes. These cells continuously produce melanin - a form of pigment. Melanocytes are found throughout our body including our hair follicles (small cavities in the skin surrounding the hair) and skin.

Melanocytes in the hair follicle give hair its colour of brown, blonde, red etc. As we age, our hair colour changes to what appears to our eyes as grey or white. This is caused by a progressive depletion of melanocytes. Scientists are currently trying to figure out why aging leads to the loss of these pigment-producing cells. Nevertheless, a loss of melanocytes results in less pigment produced, therefore, the hair appears to look grey or white.

- Dr. Chi-chung Hui, PhD, Head & Senior Scientist, Developmental & Stem Cell Biology, Research Institute, The Hospital for Sick Children, Professor, Department of Molecular Genetics, University of Toronto

Question

“Why do viruses come around?” Emmanuel, Age 8, May 31, 2011

Answer

Viruses have been around for millions of years. Over time, the tiny viruses have learned to use the cells of other organisms, such as plants, animal and humans for their own benefit. Our body, especially our immune system, tries to protect us from these viruses, and often succeeds. However, because there are so many different types of viruses, even when one virus is eliminated another virus can attack. This is why we can still catch the flu despite receiving the “flu” vaccine every winter. In addition to vaccines, we can fight viruses by preventing their spread. Frequent and thorough hand washing, as well as covering the mouth and nose when coughing and sneezing, can reduce viruses’ ability to come around.

It is also important to remember that very young babies and children who were born without a normal immune system, or children who are receiving medications that weakens their immune system, cannot fight viruses very well. Therefore, these children should be kept away from people with virus infections.

- Dr. Eyal Grunebaum, MD, Scientist, Developmental & Stem Cell Biology, Staff Physician, Division of Allergy and Clinical Immunology, Blood and Marrow Transplantation Unit, The Hospital for Sick Children, Associate Professor, Paediatrics, University of Toronto

Question

"I am ten years old and I want to become a cancer researcher when I am old enough. How do you go about doing this?” MacKenzie, Age 10, Orangeville ON., May 17, 2011

Answer

Being a cancer researcher is an amazing job! To become a cancer researcher, you first have to finish high school and then four years of university, where you are probably going to want to study subjects such as biology (studying living things), chemistry (studying how chemicals are created and work), and genetics (how genes work to make us who we are). You would then do at least another four years in University, earning a degree called a Master's or Doctorate in cancer research. During these years, you would work with a team of scientists who are doing cancer research, while doing your own cancer research project. After that, you probably would spend another couple of years with another cancer research group to learn even more. Some people want to combine a career being a cancer research and a doctor who takes care of cancer patients. If you wanted to do that, then at some point in all that training, you would spend 4 years in medical school and do several years of training to be a cancer specialist. After that, you are finally ready to start your own career as a cancer researcher, and all that extra schooling is well worth it!

- Dr. David Malkin, MD, FRCP(C), FAAP, Senior Scientist, Genetics & Genome Biology, Senior Staff Oncologist, Haematology/Oncology, Director, Cancer Genetics Program. The Hospital for Sick Children, Professor, Department of Medical Biophysics, School of Graduate Studies and Department of Paediatrics, University of Toronto

Question

"What is the difference between an atom, molecule, particle, cell, bacteria, and germs? Are any one of these composed of another one of these?" Deevya, Canada, April 6, 2011

Answer

Atoms were one of the smallest units of physical matter when first discovered. They're most simply made up of groups of protons, neutrons and electrons. The different groups make up all the basic elements that we know on the periodic table, like hydrogen, carbon, and oxygen. Molecules are larger groups of atoms that may be joined together in many different ways. In other words, molecules are a way to describe things like individual units of water, or anything that exists as a special grouping. Particles are very much like molecules, tiny pieces of anything.

Now we make the big leap to cells! They are made up of all sorts of molecules both big and small like salt, water, fats, sugars, DNA, proteins of different shapes and jobs, and more complex structures. Our bodies are made up of all different kinds of cells that make skin, bone, muscle, organs and more. Bacteria are made up of individual cells that are similar but still very different from the cells that you and I are made up of. In comparison to our human cells, bacteria are much smaller. There is even a theory that small parts of our cells are named mitochondria. They may have come from a partnership formed long ago between bacteria and other cells. Even today, within our own bodies, we live with certain kinds of good bacteria, like those found in our intestines.

Finally, germs in this context are small things that can make us sick. This includes kinds of bacteria, viruses, and fungi. Bacteria and fungi are made of different types of cells that can make poisonous molecules. These molecules spread making the cells in our own bodies sick or die. Viruses, on the other hand, are made from DNA, and proteins but they aren't as complicated as cells. Viruses can invade our own cells, and use the machines inside to make more virus particles, which is how they spread to other cells and make us ill.

- Calvin Mok, PhD Candidate, Genetics & Genome Biology

Question

"If you skip breakfast and lunch will that affect the way you learn?" Sumaiyah, Age 13, Toronto, ON., March 22, 2011

Answer

Skipping breakfast and lunch will certainly affect the way you learn. Your brain, like the rest of your body, needs energy to do its job. You get energy from the foods that you eat. So if you don’t eat breakfast or lunch your brain won’t be able to do its job. People who eat regularly through the day tend to concentrate more in school, have higher test scores, and overall seem to learn more compared to people who don’t eat regularly.

To help make sure that you have enough energy to feed your brain it is important to have a constant supply of energy. You can do this by eating both breakfast and lunch but also by including certain foods at these meals. Eating well with Canada’s food guide will help you decide what to include in your meals. Foods containing carbohydrate (grain products, fruits and some milk products) will give you energy quickly. Whole grains and foods with fibre make the energy from foods longer lasting. Protein foods (meat and alternatives) also help your body use the energy slowly so that the foods you eat at breakfast last until you have a chance to re-fuel at lunch time.

Breakfast is the most important meal of the day because it gives your body and your brain a boost to get the day started. Lunch and your other meals and snacks will help your body re-fuel to help you learn at your best.

- Jennifer Buccino, MEd RD, Clinical Educator, Department of Clinical Dietetics

Question

"Why do some people get peanut allergies?" Mya, Age 6, Amherstburg, ON., March 8, 2011

Answer

The development of allergies to peanuts and other foods more common in kids at a younger age than in adults, and many kids will still have the same allergies as an adult.

If you come from a family where peanut or other allergies are common, then, it is more likely that you could also get them. Even when asthma or eczema runs in the family, there is a bigger chance that kids will develop a food allergy. This is because our genes play a big factor in developing an allergy.

One reason why peanut allergies are so common is because of the way peanuts are prepared and eaten in certain parts of the world. For example, here in Canada, where a lot of kids have an allergy to peanuts, we like to eat them in peanut butter. Peanuts in peanut butter are roasted, whereas in places like China, kids eat their peanuts boiled or fried and peanut allergies are not as common in China.

The age that you start eating peanuts may also be a factor in causing an allergy. Allergists around the world are currently discussing the best age for people to start eating peanuts.

There may also be other things in our environment, like soy proteins or some types of pollen, that look like peanuts when they enter our bodies. If you are prone to develop an allergy then these things might give an extra push for that to happen.

- Dr. Adelle Atkinson, MD. FRCP, Clinical Staff, Immunology & Allergy, SickKids - Assistant Professor, Paediatrics, University of Toronto and Dr. Luis Murguia, MD, Paediatrician, Clinical Fellow in Paediatric Immunology and Allergy. The Hospital for Sick Children. University of Toronto

Question

"What is the purpose of a sneeze?" AJ, Canada, February 22, 2011

Answer

A sneeze is a strong blast of air that tries to push any irritating thing out of your nose. If your nose is runny, such as when you have a cold, the sneeze will spray little droplets all around you. These droplets could make other people sick unless you stop them. This is why you should cover your nose and mouth when you sneeze, using a tissue if you have one, or by sneezing into your sleeve or elbow if you don’t. You don’t want to sneeze onto your hands, because you would spread the droplets around when you touch other people or things.

- Dr. Neil Sweezey, MD, FRCPC, Senior Scientist, Physiology and Experimental Medicine, Staff Respirologist, Respiratory Medicine, SickKids, Associate Professor, Department of Paediatrics, University of Toronto

Question

"What are all those squiggly lines on an EEG and how do you know what they mean?" Students in the Epilepsy classroom, SickKids, Toronto, ON., February 8, 2011

Answer

The squiggly lines on an EEG (electroencephalogram) represent electrical signals of the brain, which are unique for every person, just like fingerprints. The lines go up or down and allow us to measure size, shape and frequency and understand the tiny electrical signals from the 100 billion neurons working together in your brain. These electrical signals move very quickly, like the blink of an eye.

The beauty of an EEG is that it changes as you grow older. Before you were born, the squiggly lines on your EEG were discontinuous and then during the first two months after birth, electrical brain signals become continuous and the ones at the back of your head or the posterior, react every time you close your eyes. Throughout elementary school, these squiggly lines learn to react every time you move your hands or do a mathematical operation like addition, subtraction, multiplication or division. As you continue learning, you can continue to change the electric signals in your brain.

When you are sleeping the electrical signals at the top of your head get bigger and faster. This shows that you are resting for energy recovery so you will be able to function well the following day. During rapid eye movement (REM) sleep, the time when you dream, brain signals are similar to when you are awake. REM sleep is special sleep when the brain treasures what you have learned during the day. Instead of saying “practice makes perfect” you can say to yourself that “practice and a good sleep makes perfect”!

The squiggly lines of the EEG are beautiful signals of the electrical activity of the brain, always in tune with your age, whether you are healthy or sick.

- Dr. Miguel A. Cortez, MD. CSCN (C) Clinical & Experimental Neurophysiologist, Co-Director of the Epilepsy Fellowship, Division of Neurology, Project Director, Neurosciences & Mental Health, SickKids, Assistant Professor, Department of Paediatrics, University of Toronto

Question

"What are the risks of diabetes during pregnancy?" Lily, Age 25, Canada, January 25, 2011

Answer

About 1 to 3% of pregnant women develop diabetes during pregnancy. This is also known as “gestational diabetes”. Most women with gestational diabetes develop it because they cannot produce enough insulin, a hormone important for blood sugar control. High blood sugar levels can be unhealthy for both mom and the baby. If the diabetes isn't treated, the baby may be more likely to have certain problems at birth. For example, the baby may have a low blood sugar level, low calcium level, jaundice, or may weigh much more than normal.

Gestational diabetes can also affect the mother’s health. If the baby is very large, there is a greater chance of having a difficult delivery or needing a cesarean section (C-section). Gestational diabetes also increases mom’s risk of developing preeclampsia (high blood pressure, swelling and protein in the urine).

Fortunately, the risk of complications during pregnancy can be reduced by controlling the level of sugar in the blood. This is done by following a diet suggested by the doctor or dietitian, exercise regularly and checking blood sugars at home with a small device called a glucometer. Sometimes medicine, such as insulin, is needed to control the blood sugar level.

After delivery, gestational diabetes usually disappears, however, women who have gestational diabetes are at greater risk for diabetes with future pregnancies and for type 2 diabetes later in life. Babies who are born to mothers with gestational diabetes may be at increased risk for obesity and diabetes as they get older.

- Dr. Jill Hamilton, MD, Staff Endocrinologist, Endocrinology, Associate Scientist, Physiology & Experimental Medicine, Associate Professor, Department of Paediatrics, University of Toronto

Question

“I hear a lot of talk about atoms and the atomic level. In terms of scope, just how small is an atom?” Jason, Age 29, Toronto, ON., January 11, 2011

Answer

It is hard to give the exact size of an atom because, like clouds, they don't have well-defined edges. Atoms are made of three types of particles: electrons, which are very light (about 0.00000000000000000000000000091 grams) and have a negative charge; protons, which are almost 2000 times heavier than electrons, and have a positive charge; and neutrons, which are only slightly heavier than protons, and have no charge. In an atom, the neutrons and protons are clustered in the centre and the electrons surround this "nucleus" in a sort of cloud.

Different atoms have different numbers of electrons and hold their electron cloud more or less tightly, which leads to different atoms having different sizes. I'll choose carbon atoms as an example because most biological molecules are partially made of carbon atoms. Carbon atoms have 6 electrons, 6 protons, and usually have 6 neutrons. For carbon atoms, the distance across the electron cloud is approximately 140 picometers or 0.00000000014 meters. That could also be said as 14 thousandths of a thousandth of a thousandth of a hundredth of a meter. That's very small, but we can actually build microscopes that use electrons instead of light and are capable of directly imaging atoms.

- Dr. John Rubinstein, PhD, Scientist, Molecular Structure & Function, Associate Professor, Departments of Biochemistry and Medical Biophysics, University of Toronto

Question

"What types of mental illnesses can arise in children with asthma?" Tammy, Age 27, Whitby, ON., December 15, 2010

Answer

A severe asthma attack can be a scary experience. It’s not unusual for children with asthma to suffer from anxiety. They need to take very good care of themselves and always be careful to avoid the triggers of asthma attacks. Asthma attacks can also place a lot of stress and strain on families of children with asthma. It’s therefore important to recognize that these families may need extra social support. Higher rates of asthma in young children have been found where there is a high level of stress within a family and especially where the mother suffers from poor mental health. Individuals reporting poor mental health are at higher risk of having asthma themselves. Among children with an anxiety disorder, about 28 per cent will also report having an allergy and about 19 per cent will also report having asthma. It’s therefore very common for asthma and an anxiety disorder to co-exist. When treating a child with asthma, doctors should ask about the level of stress in the home and whether either parent suffers from a mental health condition so that all the problems that may be contributing to the child’s asthma can be addressed.

- Dr. Wendy Ungar, PhD, Senior Scientist, Child Health Evaluative Sciences, Associate Professor, Health Policy, Management and Evaluation, University of Toronto

Question

"Why does my heart beat?" Alex, Age 5, Sherman Oaks, California, November 17, 2010

Answer

The heart, like other organs in your body, is made up of millions of cells, tiny individual machines that are too small to see without a microscope. Cells have unique jobs depending on where in your body they are working. Most of the heart’s cells have two jobs – job one is as a pump, squeezing during your heartbeat so that blood is pumped from your heart out to your lungs and body and job two is like a telephone, sending an electrical signal to the next cell down the line so that heart cells all squeeze at about the same time. In a few areas of the heart, special cells known as “pacemaker cells” don’t wait for a telephone call from their neighbor, they start the electrical signal off on their own, at a speed that depends on whether you are sleeping, sitting, walking or running. Your heart beats almost a million times a week.

- Dr. Joel Kirsh, MD, Staff Cardiologist and Project Investigator, Cardiology

Question

"Why do we itch?" Tommy, Age 19, Canada, November 3, 2010

Answer

Itchiness, also called pruritus, is the unpleasant skin sensation that leads to a desire to scratch. It is commonly associated with some skin conditions, but can also be a symptom of other diseases. The complete mechanism leading to an itch is not fully understood, but there has to be a stimulus on the skin that is detected by our nerves and transmitted to the brain as the desire to scratch.

Small receptors on the skin surface are the ones thought to be initially activated to start the itchy feeling. These receptors are activated by several substances, for example histamine or serotonin, and these release an electric message that travels through nerves. The nerve network brings this message up to a special part of the brain called the cerebral cortex and then our brain tells us we are itchy and this makes us want to scratch.

Many times by examining the skin we are able to determine the cause of the itch. For example atopic dermatitis or hives can lead to itchiness, but also insect bites or parasites on the skin can produce this sensation. When we do not find the cause of the itch on the skin, then we have to suspect other systemic diseases not localized on the skin. If we are itchy and we scratch our skin a lot, the skin’s barrier might be disrupted and bacteria or viruses can go in our skin and cause infection. This is why, if we are itchy, it is important to find the cause of the itch and treat it to avoid damaging our skin.

There are many ways to treat itchy skin, but the most effective treatment is going to depend on the cause of the itch. If the skin is dry, it is important to moisturize since dry skin is commonly itchy. It is also necessary to avoid long baths and very hot water in the bath since this dries our skin. Avoidance of irritants is also important, for example some perfumes, soaps or detergents might lead to itchiness. If there is inflammation of the skin (like for example in atopic dermatitis or psoriasis), we need to use medicated creams or ointments to eliminate the inflammation and treat the itch. Some oral medications, antihistamines for example, also help treat itchiness. If the cause of the itch is parasites, we need to use other medications to eliminate these from the skin and ease the itch. With other systemic diseases, you need to treat the disease, in order to alleviate the itch.

Our skin plays a very important role in our body’s defense against infection and the environment. It is very important to keep our skin intact so it is able to protect us.

Question

“How come some people can function fine with so little sleep, when others can get a solid 8 hours a night and still be tired?” Danielle, Calgary, AB., October 20, 2010

Answer

Most adults need 7.5 to 8 hours of sleep per night, but there are many people who need more or less than that amount to feel well-rested. There is probably a genetic component to how much sleep each person needs. The 24-hour a day demands of society -including work, school, time with family and friends, texting, Twitter and Facebook has a big influence on how late we stay up and how much sleep we actually get!

The best way to know you are getting enough sleep is how you feel the next day. The amount of sleep that allows you to wake up (maybe even a few minutes before your alarm clock goes off) with energy for the whole day is the right amount for you. Although there is variation in how much sleep adults need, we know that people who consistently sleep less than six hours at night are more likely to be sleepy during the day, have a more depressed mood and make mistakes with complex tasks such as driving a car.

People who say they need only a few hours of sleep each night may have gotten used to the feeling of being tired and may underestimate the amount of sleep they actually need. Someone who is sleeping eight hours or more a night but still feels tired may have problems with sleep such as difficulty breathing properly during sleep and should talk to a health-care professional. Also, the best sleep is achieved when you go to bed and wake up at approximately the same time each day. So, if you are sleeping eight or more hours a day, but you go to bed and get up at very different times each day, this does not allow you to have a consistent daily rhythm (also called a circadian rhythm) and may leave you feeling tired or groggy.

- Dr. Robyn Stremler, RN, BSc(Hons), MSc(A), PhD, Nursing Research Associate, Centre for Nursing

Question

"How do you know what to name different bacteria?" Delfin, Age 9, Toronto, ON., October 5, 2010

Answer

Bacteria are usually given two names: the genus and the species. Many of these names are in latin and describe the bacteria in this language. For example, Staphylococcus aureus means "the golden cluster seed" since these bacteria are round like grapes, and appear yellow. Some bacteria include the names of the people who discovered them. For example, Salmonella typhimurium is of the genus Salmonella and the species is typhimurium. In this case, "Salmonella" is named after Dr. Salmon, who discovered this group of bacteria. And "typhimurium" refers to the fact that the bacteria can cause a disease like Typhoid fever (typhi-) in mice (-murium). So the names of bacteria often say a lot about the bacteria, and help you remember details about them.

- Dr. John Brumell, PhD, Senior Scientist, Cell Biology

Question

"Why do I have to get shots?" Andrew, Age 3, Sherman Oaks, California, September 22, 2010

Answer

Bad germs can hurt your body and shots can stop these bad germs. A shot is a medicine that makes your body fight bad germs better so that you don’ t get sick. You have to get shots to help to keep your body healthy.

- Dr. Anna Taddio, PhD, Pharmacist and Adjunct Scientist, Child Health Evaluative Sciences

Question

"Can stem cells help cerebral palsy?" Denise, Canada, September 7, 2010

Answer

At this point in time, there is no published evidence to indicate that stem cell transplants can help cerebral palsy, although there are several services, including commercial ones in Europe that offer to transplant cells from the bone marrow into individuals with cerebral palsy. That isn't to say that stem cell therapies will never be useful for cerebral palsy. In fact, children have stem cells in their brains that could perhaps be activated to help their brains to repair themselves. However, right now this is an idea, for which there is currently no published support.

- Dr. Freda Miller, PhD, Senior Scientist, Developmental & Stem Cell Biology

Question

"Why won't my mom let me eat a lot of sugar?" Alex, Age 5, Sherman Oaks, California, August 24, 2010

Answer

Well first of all, it is important to remember that some sugar in our diet is necessary to give us energy. We can get this energy from sugars found in bread, pasta and potatoes, even though they don’t taste sweet and also in yummy fresh fruits.

Too much sugar though, can cause several problems. First, we may start to feel nauseous or sick to our stomachs after eating too much sugar. Also, and more importantly, if we overdo the sugar too often, our body can get ‘stressed’ and produce a lot of insulin all at once and over time we may lose the ability to produce it in the right amount during every meal. Producing too much insulin makes us more likely to get diabetes, specifically Type 2 Diabetes, in the future. Although just eating too much sugar alone does not cause diabetes, together with other bad habits such as a lack of exercise, it can certainly make people more susceptible to the disease. Diabetes can be a very serious disease that over time can affect our vision, our nerves, our kidneys and our heart.

Another problem that comes from eating too much sugar is tooth cavities which can result in many trips to the dentist. To avoid these problems, it is important to listen to your mom and not eat too much sugar and also avoid sugary drinks like pop, fruit cocktails and sweetened juices.

- Dr. Amira Klip, PhD, Senior Scientist, Cell Biology

Question

"Why do kids get epilepsy?" Nellie, Age 10, Toronto, ON., August 10, 2010

Answer

There are many, many reasons that children get epilepsy. These range from abnormalities in the development of brain, infections of the brain, traumatic brain injury, birth injury to brain, and a variety of genetic causes. In addition, in many children who have epilepsy we never determine a cause. We attempt to find out the cause by a careful history of the seizures in terms of onset and what they look like, a careful family history and past medical history of the child, and a neurological examination. Laboratory tests depend on where the history leads us, but we almost always obtain a brain wave. Brain imaging such as CT scan or MRI scan of the brain is not routinely done unless the seizures or the history suggest that there might be an anatomical lesion of the brain.

- Dr. Carter Snead, MD, FRCP(C), Division Head, Neurology, Senior Scientist, Neurosciences & Mental Health

Question

"What causes pimples and what are the best ways to remove or keep them down using natural remedies?" Dillon, Toronto, ON., July 27, 2010

Answer

Several things lead to the development of pimples or acne. Hormones, which are special chemicals in the blood that help control our body functions, change around the time of puberty. Certain hormones are increased and this causes changes in the body. One of the changes that can be caused by hormones is that the oil glands in the skin start making more oil. This oil goes from the glands, deep in the skin and comes out onto the skin though the pores, which are small openings seen on the face. This oil can get stuck in pores and contribute to “clogging” them. The old skin cells that are in the pores need to be removed each day to make room for new cells. This is called skin shedding and is a normal process. In acne, those cells can become trapped along with the oil in the pores and can also contribute to clogging. The two other factors that can lead to acne are certain bacteria that normally live on the skin and inflammation which is when the body causes redness and swelling and sometimes pus. All these factors come together to make different types of pimples: whiteheads and blackheads (called comedones), pimples and pustules.

Acne can’t be completely prevented. However, as some of the above processes start to increase in the teenage years, and sometimes into adulthood, they can be treated or controlled. Good skin hygiene including simple wash routines and eating a healthy diet may contribute in a minor way to acne management. These are both good natural ways of addressing acne. However, for more significant pimples, medical therapies might be appropriate. It is important to discuss this with your doctor. Avoid “picking” and “popping” pimples because this can lead to scarring and an infection on top of the pimples.

- Dr. Miriam Weinstein, MD, Staff Physician and Dermatology Fellowship Director, Section of Dermatology and Project Investigator, Paediatric Medicine; and Assistant Professor, Department of Paediatrics and Faculty of Medicine, University of Toronto

Question

"Does eating carrots actually help your eye sight?" Sarah, Age 15, Tecumseh, ON., July 13, 2010

Answer

Carrots have Vitamin A in them and this vitamin is used by the retina to see. Having too little Vitamin A can cause problems with eye sight. However, this doesn’t mean that having lots of Vitamin A gives you super-vision. In fact, too much Vitamin A can be harmful in some cases. In general, carrots should be eaten in a moderate amount as part of a healthy diet.

Now that the science is out of the way, here's a little joke to tell your friends about carrots:

Why are carrots good for your eyes? Because I have never seen a rabbit wear glasses!

- Dr. Kamiar Mireskandri, MBChB, FRCSEd, FRCOphth, PhD, Staff Opthamologist and Project Investigator, Opthamology and Assistant Professor, Department of Opthamology and Visual Sciences, University of Toronto

Question

"Why are babies born with defective hearts?" Drew - Age 9, Palmerston, ON., June 29, 2010

Answer

Babies are born with defective hearts for many reasons. One of the reasons is that the genes that control how the normal heart forms are missing or defective. Think of genes as a string of millions of beads. Each bead carries a code that sends the message to form various body parts. If a bead is missing or defective, then this code or message is lost or is misread, and the organ does not form properly. In some cases, this defective gene is passed down from a parent to a child. The heart is like a pump with many screws and bolts and valves and connections and even one missing connection can make the heart pump defective. In some cases, heart defects occur because the mother was exposed during her pregnancy to smoking, alcohol, infection, some types of medicines, chemicals, and other damaging agents. Unfortunately, we still do not know all the causes of defective hearts but we are finding more and more each day.

- Dr. Seema Mital, MD, FACC, FAHA, FRCP(C), Staff Cardiologist, Cardiology, Associate Scientist, Genetics & Genome Biology

Question

"With the numerous types of HIV mutations, would an HIV vaccine really be effective?" Tommy - Age 21, Toronto, ON., June 15, 2010

Answer

Making a vaccine to completely prevent HIV is going to be extremely difficult. There are several reasons for this. First, there are many different strains, or “clades”, of HIV. Because these clades differ genetically from one another a vaccine may work against one, but be completely ineffective against another. Second, the best potential protein targets of an HIV vaccine (preserved between clades) are hidden deep within the protein structure making it difficult for antibodies to bind to them and neutralize the virus. Third, vaccines work by helping the immune system respond to an infection, but ultimately it is the immune system that must eradicate the infection. Unfortunately, HIV is different from vaccine-preventable infections in that the immune system is not able to eradicate HIV from the body. All this said, it is important to note that as our understanding of the biology of HIV and the immune system response to it improves, it is possible that we will be able to devise new methods, not thought of previously, to develop an effective vaccine.

- Dr. Sean (Ari) Bitnun, MD, MSc, FRCPC, Staff physician & Consultant in Infectious Diseases, Infectious Diseases, Assistant Professor, Paediatrics, University of Toronto

Question

"How does cancer grow and spread?" Bond - Age 9, Toronto ON., June 1, 2010

Answer

Cancer starts when one cell somewhere in the body stops working properly and starts to divide much more quickly than it normally should. The genes in the cell that would usually program the cell to stop dividing or stop growing don't work properly. Other genes start to tell the cell to invade tissues nearby and from there to spread through the blood stream or directly to other organs of the body. Eventually, these cancer cells multiply so much (making trillions of themselves), they cause severe damage to normal body organs or use all the nutrients and oxygen that the body needs to survive. Eventually, unless it's treated, the cancer builds up to the point that the person in which it started, cannot survive. Fortunately, for children, most cancers can be cured!

- Dr. David Malkin, MD, FCFP (C), FAAP, LMCC, Senior Staff Oncologist, Haematology/Oncology, Co-Director, Cancer Genetics Program, Senior Scientist, Genetics & Genome Biology

Question

"Does gum really stay in my stomach for 7 years?" Cameron, Age 9, Toronto, ON., May 18, 2010

Answer

If you accidently swallow a piece of gum you have been chewing, it does not stay in the stomach. As part of the normal way you digest food, it has to be moved through your digestive tract (which is like a long tube) to be digested properly and the nutrients absorbed. After you swallow the food moves from the esophagus (swallowing tube), stomach and intestines until it eventually comes out as feces (poop!). This movement of food that is getting digested is called peristalsis. Although gum isn't food and not digested the same way, it is pushed through the gastrointestinal tract and out into your poop.

- Dr. Nicola Jones, MD, PhD, FRCP(C), Staff Gastroenterologist, Gastroenterology, Hepatology and Nutrition and Senior Scientist, Cell Biology

Question

"Does everyone see the same colours? Is it possible that my green is another person's red?" Spencer - Age 14, Tecumseh, ON., May 5, 2010

Answer

That is absolutely correct. Spencer's perception of red may look the same as another person's green. Colour vision is abnormal in about 8 per cent of males. At the back of the eye there are special receptors to light that pick up light in a red direction, a green direction and a blue direction. Some males (and very few females) have either the red or the green receptor missing. This means that a red and green light may look the same colour. However, the blue receptor is rarely missing. This means that purple (red and blue) will look different to orange (red and yellow).

- Dr. Carol Westall, PhD, BSc (Optom), Vision Scientist, Ophthalmology and Vision Sciences and Senior Associate Scientist, Neurosciences & Mental Health

Question

"When you chomp on your food, and then it goes down the slide into your stomach what happens to the food when it goes into the intestines?" Callum - Age 4, Vancouver, BC., April 21, 2010

Answer

When you chomp your food it gets smashed and broken up in your mouth. Then it goes down the slide called the esophagus into your stomach where it sits for awhile. Juices from your stomach continue to break up the food and the stomach muscles mash it together into little balls. The balls of food then go into a large tube called the small intestine. In the small intestine, the balls of food are smashed up even more so your body can get all the important nutrients it needs including vitamins, minerals, proteins, sugars, and fats. Finally, the food balls enter an even bigger tube called the colon where your body gets all the water and some more minerals from the food before it leaves your body as poop.

- Dr. Aleixo Muise, MD, PhD, FRCPC, Gastroenterology/Hepatology/Nutrition

Question

"Why do I get light headed when I first stand up?" Gemma, Age 15, Staples, ON., April 7, 2010

Answer

Dizziness immediately after standing can result from a temporary drop in blood flow and therefore oxygen to your head. In medicine this is sometimes referred to as “postural hypotension” - postural meaning body position and hypotension meaning low blood pressure.

Standing, especially after a long period of lying down, can result in blood being pulled by gravity away from your head and chest into your lower body. This momentarily reduces the amount of blood returning to the heart, which results in lower blood pressure and less blood flow to your head, causing dizziness.

Luckily, your body will detect this and can react quickly – your heart will beat faster and your blood vessels will contract to direct more blood to your head.

- Dr. Christopher Macgowan, PhD, Scientist, Physiology & Experimental Medicine

Question

"What makes a non-cancerous tumour different from a cancerous one?" Alayna, Age 24, London, ON., March 24, 2010

Answer

Cancerous tumours are made up of cells that grow very fast and can move to places where they don't belong. In contrast, non-cancerous tumours (also called a benign tumours) do not usually grow or spread to other parts of the body. An example of a non-cancerous tumour would be a mole on your skin. The reason cancerous tumours grow without control and spread is because their cells have acquired mutations in genes that normally prevent them from growing and moving to other organs and tissues.

- Dr. Brent Derry, PhD, Scientist, Developmental & Stem Cell Biology

Question

"What is the cure for hiccups?" Alexandra, Age 15, Tecumseh, ON., March 10, 2010

Answer

Cures for hiccups date back centuries and most recommendations are based on anecdotal experience rather than controlled scientific studies. Some people believe that holding one’s breath helps stop hiccups. But does this really work? A variety of remedies that temporarily bring breathing to a halt -- such as sneezing, pulling knees up to the chest or being surprised by a sudden fright -- have been reported to be effective in stopping hiccups and indeed, there may be scientific validity to this remedy. There is a theory that a cycle of activated nerves that control movement of the diaphragm is responsible for inducing hiccups. Breath holding breaks the cycle and stops the hiccups. There are those who believe that the trigger point for hiccups is at the back of the palate near the uvula (hang ball) and that hiccups can be stopped by stimulating the back of the pharynx with a spoon or by sipping ice water. Others have recommended swallowing a teaspoon of dry granulated sugar as a successful means of interrupting the hiccup cycle.

Hiccups affect almost everyone, are difficult to avoid, have no known useful purpose and must be endured until they simply pass on their own. The use of one of the many harmless suggested remedies, such as breath holding, may help you feel that you are doing something until nature takes its usual course.

- Dr. Moshe Ipp, MD, Paediatrician and Project Investigator, Paediatric Medicine

Question:

"How come you can’t store up your sleep? For example - Why can’t you sleep for 14 hours one night and then be rested after sleeping for only a few hours the next night?" Katie, Age 26, Midland, ON., February 24, 2010

Answer

The exact reasons for why we sleep surprisingly remain unclear to most scientists. Many believe that sleep represents a time that the brain reserves for itself to learn or rewire itself, like re-fragmenting a hard drive. Others believe sleep represents a time for the body to repair itself from the stresses of the day. While the function of sleep remains a mystery, it is well known that humans need sleep to function and sleep deprivation usually results in limited abilities to learn, remember and perform daily tasks, but it can also lead to increasing harm to the body.

The precise timing of sleep really reflects two major forces, called a circadian and homeostatic sleep drive which both serve to entrain our brain to determine what time we sleep and what time we wake up.

In the circadian sleep drive, the strongest determinant in length of sleep is exposure to light, more specifically sunlight. The eyes sense light, and a lack of light stimulates a gland in the brain, called the pineal gland, to release melatonin, a hormone that tells the brain that sleep should begin soon. Exposure to sunlight in the morning signals the brain to stop releasing melatonin and we feel awake.

The other regulator of sleep, the homeostatic sleep drive, is related to the molecule adenosine. Adenosine levels build up in the brain the longer you stay awake. At a high level, adenosine will then help the brain determine when someone has been awake for too long thereby triggering the brain to initiate sleep. Once asleep, adenosine levels fall until a level where it no longer stimulates the brain to stay asleep which allows us wake up. Interestingly, caffeine promotes wakefulness by inhibiting adenosine.

- Dr. Rakesh Bhattacharjee, Sleep and Respiratory Medicine

Question:

“I know that scientists grow cells in their labs. What do the cells eat?” Jaden, Age 5, Markham, ON., February 10, 2010

Answer:

We grow cells in a clear liquid media that looks just like “Kool-Aid”. It’s pinkish and it has all the nutrients that cells need to grow. The nutrients include sugar, amino acids and minerals like iron and magnesium. We also put a small amount of cow serum (the part of our blood without any red or white blood cells) into our media since it has specific growth factors to tell cells to grow.

We grow cells in this media and they double in number every two to three days. After that we have to change the “Kool-Aid” and dilute the cells a bit so they don’t get too concentrated in the dish. If they grow too much, and get too concentrated, they start to die off and we can’t do our experiments.

- Dr. John Brumell, PhD, Senior Scientist, Cell Biology