CU Mini Med School 2008 Information and Answers to Questions

If you're interested, you can browse the questions & answers from the 2007 Mini Med School by clicking here.

Anatomy and Physiology 1

Q: What is the difference between MRI & CAT Scan?

A: CAT scans are a form of x-ray, in which the x-ray source and the film or digital detector plate move together so that only a thin “slice” of the patient's body is in focus; this reduced radiation dose somewhat, and allows much sharper images than the traditional x-ray, which images the entire thickness of the body part at once. MRI scans do not use radiation; a large magnetic field temporarily lines up all water molecules in the body, and then a smaller, very brief magnetic field (the “click” you hear) makes some of the molecules move out of alignment. As they return to where they were before, they give off a radio-frequency signal which can be captured and computed into an image.

Q: What is a stimulus?

A: Anything that results in a response. I show you food (the stimulus); you drool (the response).

Q: I recently had my appendix removed and I was wondering what does the appendix do?

A: Not much, fortunately. Some people think it is simply a reservoir of “good” bacteria for your intestines, in case the ones normally there get wiped out by disease or maybe, antibiotic treatment.

Q: Once you're diagnosed with Type 2 Diabetes, is it possible for someone to keep it under control without medication?

A: Absolutely. Many people do so by a combination of weight loss and diet. A healthcare provider's advice is essential to do this right.

Q: Has it ever been determined how many ailments the human body can be affected by?

A: Interesting. Probably, no two people's diseases are ever the same, even if they have the same diagnosis; that's why for one person drug A works and for another only drug B will do it. So there are, probably, as many diseases as there are people with diseases!

Q: Why does a person loose his/her sense of smell? Is there any way to repair a missing sense of smell?

A: Many possible reasons, all of which require you to see a doctor sooner rather than later. Some are treatable, others not.

Q: If carbohydrates and proteins are equivalent why do some people gain weight on a high protein diet? No carbs, what is the difference between a carb and protein?

A: They are equivalent only in the number of calories they provide per gram eaten (4). Otherwise they are chemically completely different. Proteins are broken down to amino acids which are then built up into new proteins; the same with carbs, which are broken down into simple sugars which then are the building blocks of more complex structures. A good diet is balance among proteins, carbs, and fats, all of which are essential in the proper amounts to health.

Q: My mother was recently diagnosed with a rare disease that involves the filtration of proteins, I'm unsure of the name. Are there any ways, or things, to do to help with this process of filtration?

A: It doesn't sound familiar to me, and I'm not sure where the proteins might be filtered. If you can learn the name of this diagnosis, perhaps we can tell more about it.

Q: What causes flatulence?

A: Bacteria in the large intestine, and something for them to eat. Usually there are not too many nutrients left in the intestinal contents by the time they get to the Large Intestine, which is where most of the bacteria live. If there are nutrients, the bacteria can ferment them, producing hydrogen, methane and some other gasses. In rare people with lactose intolerance, for example, milk sugar gets through to the Large Intestine because it isn't digested, and then the bacteria have a field day. Beans contain carbohydrates which we can't digest, but—oh boy, the bacteria sure can.

Q: My sister (35 years old) suddenly lost sight in one of her eyes and the other one is OK. What could be the cause? Is there any medication?

A: I hope she went to a doctor immediately! That is a true medical emergency.

Q: What do the tonsils do?

A: They are small lymph nodes towards the back of the throat. They don't do anything that any other lymph node does, that is, they are part of the immune system. Just one small part, so removing them does no harm. Usually they are removed when the mucous membrane above them, which is rather wrinkly, keeps serving as a niche for infection by Streptococci.

Q: How is it that one part of the pancreas (the endocrine function) can work okay, but the other part (the digestive enzymes) doesn't work fully?

A: They are really two completely separate organs that just happen to be located in the same place.

Anatomy and Physiology 2

Q: What causes occasional swallowing problems, this is usually when there is a long gap between meals?

A: Unless it's just that there is also a long gap between drinks, so that the mouth and throat are very dry, this seems like a question for your health care provider who can ask more questions and possibly do some tests.

Q: Please explain the mechanism, if any by which arteriosclerosis plaques in the coronary arteries might be reversed.  Would statins play a role? Specific diets?

A: There is a little evidence that reducing the LDL level with statins can partially reverse plaque; and some evidence for the very low fat Ornish diet. Also, for exercise.

Q: Regarding the brain testing with the green and blue and red areas. Would an autistic person's brain show the same results?  I'm not sure if this is still the thinking, but I thought it was believed that the wiring of an autistic person's brain is different and they don't receive messages the same way as you or I.

A: There have been many papers published describing different responses on standard functional Magnetic Resonance Imaging tests by autistic as opposed to control subjects. If you go to the National Library of Medicine at http://www.ncbi.nlm.nih.gov/sites/entrez and enter the search terms fMRI autism, you'll get about 500 papers whose abstracts you can look through.

Q: Please discuss heat syncope - especially in small/young children. Why does it occur and what can be done to prevent fainting spells?

A: Hydrate! That's far and away the most important. Little people have a much larger surface to volume ratio that do adults, so they lose water by evaporation more readily; and because of the large surface, they can absorb heat more readily, too. Water is probably as good as sports drinks unless you're doing really intense exercise. For infants, consult your pediatrician.

Q: What journal was the psychopaths study in?

A: Greg Miller : Investigating the Psychopathic Mind. Science 5 September 2008: Vol. 321. no. 5894, pp. 1284 – 1286

Q: Why does it take so long for very small children/infants to "get over" coughs?

A: A hard question, and I'm not sure there is one specific answer. They don't cough as efficiently as adults, for one thing. So material that an adult might cough up and out, tends to recycle in an small child.

Q: From last week's presentation I understand that the small intestine is one cell thick...this seems impossible..wouldn't a colonoscopy perforate it?

A: That must have been a misprint or mis-statement. The lining is indeed one cell thick in many places, but that cell layer sits on a very tough wall of muscle and connective tissue.

Q: What are mini strokes?

A: Very small blockages of small brain arteries. Usually so few brain cells are compromised in an individual mini stroke is that there are no symptoms. But if many mini strokes take place, often over a period of years, there can be accumulated damage, even severe personality changes that the family doesn't notice because they happen so gradually. Often the cause is tiny blood clots being shed into the blood from a heart chamber (usually the left atrium) whose beat is irregular.

Q: Regarding the discussion of the brain's penchant for blood, where does the concept of chemotherapy drugs not crossing the blood barrier fit?

A: There are some chemotherapy drugs that do cross the blood brain barrier and they are the ones that are preferentially used in brain cancer. Also, the tissue disruption that cancer causes can open the blood brain barrier. New drugs are being developed that can carry medication across the barrier, too.

Q: When babies first display their social smile is it a result of social stimulus or the maturation of the fusiform face area of the brain?

A: This is a very interesting question, and I don't know whether studies of the fusiform area have been done in very small infants. Several studies have shown that what's really going on is the infant is training the mother by offering her smiles when she does something that pleases the infant.

Q: What parts of the ear don't work when someone becomes hard of hearing?

A: It can actually be any part of the year. That's why audiologists have specialized tests for localizing the problem and recommending appropriate treatment.

Q: Is the left ventricle more important than the right ventricle?

A: The left ventricle is bigger because it has a more difficult job to do, sending blood all around the body. But the blood it sends comes from the right side of the heart via the lungs, so they are equally important.

Q: When the left side of the heart in an infant (hypo plastic left heart) not developed, what is the valve or tube called and located that is supposed to close when the infant is born?

A: From the American Heart Association: In hypoplastic left heart syndrome, the left side of the heart -- including the aorta, aortic valve, left ventricle and mitral valve -- is underdeveloped. Blood returning from the lungs must flow through an opening in the wall between the atria (atrial septal defect). The right ventricle pumps the blood into the pulmonary artery and blood reaches the aorta through a patent ductus arteriosus. (The ductus arteriosus short-circuits blood from right to left in a fetus, where there is no point in pushing the blood through the lungs. It closes shortly after birth in newborns with a normal heart.)

Q: What exactly happens when a retina detaches?

A: The jelly-like material that fills most of the eye is called the vitreous humor. It has fiber like strands in it that attach it to the retina. Sometimes these strands will pull on the retina and they can detach it from the back of the eye. If this happens the retina can often be reattached using a laser. If this cannot happen, or too much time has passed, the retina may lose part of its function.

Q: I know we touched on this subject in class, but I was wondering what causes people to have occasional swallowing problems? It's not a frequent issue, but sometimes it is hard for me to swallow food. Thanks a lot!

A: There are many possible reasons. Probably the most common is dry mouth which can be normal or due to an abnormal condition. There also can be a variety of abnormalities in the muscles or nerves of the swallowing mechanism, and therefore a specialist, for example an ear, nose, and throat doctor, should be consulted.

Q: In the instance where the heart has stopped there is no electrical activity, so an AED shock will not help, how would medical staff attempt to restart the heart?

A: An external defibrillator is designed precisely for use on a heart that is either beating irregularly so that it is not efficiently pumping blood, or has stopped beating for a short time.

Q: How can you determine if your arteries are becoming occluded?

A: This would be addressed as part of a complete physical examination.

Q: What can cause a scar in your lungs?

A: Many things can. Perhaps the most common, especially in those of us that have reached a certain age, is the result of an infection that took place many years ago; perhaps even a mild case of tuberculosis that was never diagnosed.

Cell Biology

Q: Many types of sunblock contain nano-particles; do they serve any particular purpose in blocking UVA/UVB radiation, and can they pose any danger on a cellular level?

A: Nanoscale particles (1 to 10 nm diameter) are small enough to interact with photons, reflecting and refracting them (so, glass with suspended gold nanoparticles in it appears vivid red, a fact known to the ancient Egyptians). So it seems likely that certain nanoparticles could act effectively to absorb or reflect UV radiation. Although such particles should not penetrate intact skin, this is something that we do not know completely, and work to find out is ongoing. So far, no reliable evidence suggests that the sun blockers are harmful.

Q: How strongly genetic, if at all, is ALS (amyotrophic lateral sclerosis)?

A: The simple answer would be that 10% of adult cases of ALS are familial; the rest are “sporadic,” in that there is no family history. Although a single gene is strongly implicated in ALS, not all cases have any mutation in that gene; other genes in the same pathway may be affected, leading to a similar clinical picture. And even in the familial cases, it is not always the same mutation, so that in some families the disease is inherited recessively, in others dominantly. The sporadic cases probably represent mutations in single individuals, but few have been identified so far.

Q: Anti-oxidants of wine affect the liver in a good way, but what about the effects on alcohol on the liver?

A: Not so good. But it seems that a glass of wine a day for women, and two for men, is far more beneficial than harmful. Not for pregnant women, though; and the jury is out on nursing mothers.

Q: Is there research being done on the regenerative properties of lamb cells on the human genome?

A: Is “lamb” as misprint, or are you referring to a specific use of lamb cells? We are not familiar with this idea. Please let us know at john.cohen@ucdenver.edu

Q: Many people decide to store blood from the umbilical cord when they have a baby, hoping that it can be used to cure problems that the baby may develop in the future. What are the odds that this will really work?

A: It depends on the problem. Cord blood has a high concentration of hematopoietic stem cells compared to adult blood, so it can be used if the child requires that in the future (odds, of course, would be very low.) It would be the equivalent of a bone marrow transplant, without immunological complications because they would be the recipient's own cells. Most needs for such treatment would come after the third decade, and we aren't sure how viable the cells would be after 30 or so years of storage. Could such cells, in the future, be reprogrammed for other purposes? Maybe.

Q: What is epigenetics?

A: This means the ways in which gene expression can gene changed, without a change in the underlying sequence of the DNA. The reason a muscle cell is different from an ovarian cell, for example, is not genetic changes (they have exactly the same set of genes) but changes in gene expression; so that contractile proteins are made by the muscle but those genes are suppressed in the ovarian cell. In every cell in a female, one X chromosome is “turned off” epigenetically. We think epigenetics might explain why, in some cases, whether you got a harmful gene from your mother of father might make a difference in your symptoms; it may be that, for some reason, one or the other gene was silenced epigenetically.

Q: My adopted son has a trait beta thalassemia. Is there any new information about this genetic condition?

A: There is a recent review that is full of information. It is somewhat technical, but we know you have the motivation to plough through it! It seems to be available free on line at http://asheducationbook.hematologylibrary.org/cgi/content/full/2004/1/14

If you can't access it email john.cohen@ucdenver.edu

Microbiology

Q: What causes a virus to mutate and how long does it take before it mutates?

A: Not all viruses mutate rapidly; it depends on the fidelity of their replication machinery. Most use the cell's own mechanisms exclusively, so there is a low mutation rate (measles and smallpox changed very little over millennia). Ones that have some of their own replication enzymes, like HIV, are highly prone to mutation because these enzymes do not “proof-read.”

Q: More about prions - what about CWD? Is this transmitted in urine?

A: There seems to be no evidence for infectious prion proteins in urine. However, breakdown products of the prion have been detected in the similar BSE of cattle, suggesting that their measurement might provide a convenient test for the presence of prions in the animal in future.

Q: What is a retro virus?

A: The AIDS virus is a retrovirus. These have their genetic information as RNA, and copy it “backwards” (retro) into DNA so that the DNA copy can then be transcribed into many more RNA versions for packaging as new viruses. Some retroviruses can cause cancer.

Q: Please discuss the use of honey impregnated bandages on open wounds for infection control.

A: This is in the alternative literature. The only scientific test of this treatment was reported in 2008; it concluded: “Honey-impregnated dressings did not significantly improve venous ulcer healing at 12 weeks compared with usual care.”

Q: Why do some pediatricians not encourage flu shots?  I've never had a flu shot and neither has my 2-year old daughter.  Does she really need one?

A: They all should. Maybe it has to do with the 7 minutes they average spending with patients? Yes she does.

Q: My daughter who lives in Weld County, CO, (Greeley) had West Nile Virus at age 28.  She experienced temporary (2 day) paralysis in her arms.  Can the virus be dormant in her body and reappear later in life like chicken pox does with shingles?

A: We don't think WNV goes dormant in people, though it can in animals in which it has had centuries to adapt, like certain migratory birds.

Q: Can scarlet fever be a long term disease? What is the typical duration of scarlet fever?

A: The acute disease lasts a week or two. But there can be long-term complications, as will be discussed in the Immunology class.

Q: Can you elaborate on why folks might choose not to vaccinate? Is there a concern about vaccine resistant infections organisms?

A: Yes, some organisms change and so evade vaccines; flu is typical, so we have a new vaccine each year. Most fear of vaccines is based on erroneous information. Vaccines are always much safer than the diseases they prevent.

Q: How do you know how to make a vaccine sufficiently strong to activate the immune system, but not make people sick from it?

A: Basically, lots of testing, and 200 years of experience.

Q: How do you predict what the next influenza virus will look like - and how to make the proper vaccine?

A: The WHO meets in February, sees what's in the Pacific and Australia, and makes an educated guess; they are right over 90% of the time.

Q: Is immune globulin from blood?...is it still available?..and how can a patient request it?

A: It is from pooled normal blood, and is available and used rarely; only a physician should ever prescribe it. A newer product has mostly replaced it; much safer but very expensive (IVIg).

Q: What is the reason for suggesting that a person keep hands away from the eyes during the flu season. Is this an infection avenue?

A: Yes. You usually acquire the virus on your hands, and it enters through a mucous membrane. The eye has fewer antiviral protections than the mouth, so it's a relatively good way to inoculate yourself with virus from your hands.

Q: Is a person allergic to penicillin at greater risk of dying from a bacterial disease at some point in his/her life?

A: Nope.

Immunology

Pathology

Pharmacology

Cancer