We've Sequenced the Human Genome. So Why Haven't We Cured More Diseases? | Discover Magazine2/24/2020 Good evening all,
In class, we have talked a number of times about how our phenotype (our physical appearance and characteristics) stems from our genotype (the particular set of alleles that we have in our genome). We've also considered how phenotype and genotype are related, by examination of a handful of traits which are influenced (all, or mostly) by individual genes (such as the trait for freckles, or attached earlobes). These examples allow us to evaluate the relationship between alleles (such as dominant and recessive forms), to consider patterns of gamete formation and potential crosses (via Punnett squares), and to assess familiar patterns of inheritance (via pedigrees). These relatively straightforward examples suggest that other aspects of our genetic health, such as disease risk for a variety of conditions, might also be similarly simple: easy to diagnose, and potentially easy to fix, if problematic. Alas, this is not the case for most traits of human disease concern. I'm forwarding here a link to an article which nicely describes why the genetic basis of our health is not so straightforward, or easy to manipulate. In reality, most of our important human diseases are only very weakly linked to individual genes, which themselves may play only a very small role in influencing our individual disease risk or expression. https://www.discovermagazine.com/health/weve-sequenced-the-human-genome-so-why-havent-we-cured-more-diseases So, of what value then is this massive Human Genome Project, this effort to sequence, and understand, every single one of our genes? Well, in short, we do not yet know its full value, as we are still learning how to mine this enormous database. It seems very likely to yield important insights into our genetic disease risks, but it has not led to the immediate creation of a broad spectrum of ready, easy-to-use, off-the-shelf treatments for our human diseases. That day of individualized, genetic approaches to health is coming, though - the first individually-based genetic treatments are now in use. They are as yet not broadly proven, and they remain enormously expensive. But, they represent proof-of-concept types of studies, which suggest that, as our knowledge and technology improve, the days of the 'genome card' are coming. Save some space in your wallets... Have a great evening - Dr. Nealen
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Good evening all,
Week after recent week, the global spread and impact of the new 'Wuhan' coronavirus continues to dominate our science and health news. Most health experts appear to have underestimated how easily this virus would spread, how long it it would persist, and how damaging it would be for global functions like travel and commerce. In terms of its lethality, this coronavirus is far less dangerous than the seasonal influenza (the "flu") that we experience each winter here in the U.S., which typically is associated with 3-10x as many deaths annually in this country alone than have been attributed to the Wuhan coronavirus worldwide. Still, this Wuhan coronavirus (more specifically, Covid-19 coronavirus) is a very good demonstration of the fact that infectious diseases do not have to be especially lethal to be very problematic. Given the scale of disruption this virus has caused, it is no surprise that a variety of treatment and preventative efforts are underway, including attempts to develop effective screens for infected persons, as well as tests of potential immunizations to prevent the contraction of the disease. One of the less well-publicized efforts is the attempt to identify "patient 0" - the first human to "catch" the virus. Of what value would it be to find this first human subject? In theory, this would allow scientists their best hope of finding the original source of the virus, the animal species from which the virus made its leap to human hosts. Identification of the animal host reservoir (be it bat, snake, pig, or other) could help limit future spread of the virus, and may also inform biological efforts to combat it. The more we know about the virus, the better our chances to counter it. But, there may be drawbacks to finding "patient 0", as outlined in this recent article: https://www.bbc.com/future/article/20200221-coronavirus-the-harmful-hunt-for-covid-19s-patient-zero Is there more harm to be done, or more gain, in finding this first human subject? Experts disagree, but not yet to the point at which the search for this first subject will cease. Finding the original subject in a disease outbreak is a standard epidemiological technique, and there are plenty of examples (including several described in this article) in which finding that first human host of a new disease agent was helpful. Still, the article also describes the risk of stigmatization, and error - what if someone is wrongly identified as the starting point for an epidemic? In this country, and in other developed nations, there are relatively standardized procedures for dealing with newly emerging diseases. When a new pathogen or new disease begins to spread that eclipses scientific expectations, however, some of the cracks in our defenses begin to show, and efforts to combat the new condition often become less uniform than would be ideal. We are seeing exactly this in recent weeks: there is open debate about how to count the number infected by this virus, continued uncertainty over its origins, and newly emerging evidence of how spectacularly unsuccessful quarantine efforts can be. We still have much to learn, it seems. The good news is that the virus really is of relatively minor risk to healthy individuals. We've no nearby cases here in Western PA, but should it appear, remember that the best defenses are surprisingly simple: avoid contact with infected individuals, and wash your hands well with soap after public forms of contact. Common sense is equal to best practice, in this case. Have a great evening - Dr. Nealen Good morning all,
I'm passing along here (at page bottom) a link to a recent news article about genetic sleuthing of the source for the 'Wuahn coronavirus', the virus that appears to have made its first appearance in humans and now is causing tens of thousands of infections, and perhaps >1,000 deaths, worldwide. As you now, this has been the top genetics and health news story for several weeks now. Viruses are a bit of an evolutionary quandary. They are tiny objects, composed of protein and nucleic acid. They are not considered to be cells, and they are not considered to be 'alive'. They are parasitic 'replicating devices' - they can only replicate when they have successfully infected the cell of a host species. And, they are designed to take-over the protein machinery of their host's cell, causing it to make many more virus particles, and to spread them. https://en.wikipedia.org/wiki/Virus Mammals have evolved with viruses throughout our history, and our immune systems contain some viral defenses, just as our genomes contain bits and pieces of DNA that may have been viral in origin. In recent years and decades, we have increasingly been aware of 'new' viruses, not previously seen in humans, that are suddenly causing human disease. Swine flu, avian flu, MERS, SARS, and others - and now, the Wuhan coronavirus. Why are viruses so common in mammals? Because we are really good hosts for them - lots of cellular protein machinery, warm-blooded cells which promote high rates of viral replication, dense social structure which promotes transmission. From rats to cats, bats, camels and more, each mammalian group bears its own viral load. Why do viruses move between mammal species? Two words: mutation and opportunity. As viruses mutate, they can gain or lose features that make them better, or worse, suited for particular host species (e.g., cats versus dogs). As species co-mingle, the odds improve that a virus can successfully 'make the leap' to a host of a different species, one to which it is newly well-suited. Why are so many of these novel viruses originating in Asia? Population density and food production practices. On the global scale, the U.S. is relatively sparsely populated (save our largest cities). Across the globe, it is very common for population densities to be much higher than those found here. And, high human densities require ramped-up food production. Much of food production here is commercialized and removed from the public, but again, this is a global exception. Across most of the world, food production tends to be on a smaller scale, and it tends to be much more personal - individuals tending their own animals, working with their tissues and bringing their own products to open market. Together, this density and close contact ups the risk of transmission of animal viruses to human hosts. This article describes genetic efforts to identify the original animal source of the human virus, as well as to characterize the virus more fully. The more we know about the virus, the more likely we can stop the spread of infections and develop effective preventatives (such as a vaccine) and treatments. https://www.sciencemag.org/news/2020/01/mining-coronavirus-genomes-clues-outbreak-s-origins I will occasionally pass along articles of this type during the semester. My purpose in doing so is to help you to become more aware of topics at the interface of biology and society, and also to help you assess how you obtain your science and health news. Those of us working in science obtain our scientific news, quite often, directly from the original sources: the people conducting the studies and reporting the results. They publish their findings in science journals, or present them at conferences. Most people do not obtain their news directly, but hear news via secondary sources, such as news releases from scientific organizations, or news stories from the major news outlets. These secondary reports often are then carried by tertiary outlets (smaller/other reporting sources). Along the way from source to audience, science news is normally distilled (a lot) - much of the detail is excluded or simplified, and the reports often are boiled-down to singular take-home messages, which may (or may not) be good representations of the original work. When you browse the links that I will forward, or when you access science and health news on your own, I'd encourage you to delve a little bit deeper into them, to read more than just the summaries, and to follow links back to original sources when possible. I'd also encourage you to think a little about the translation of news from source to consumer, and the reputability of the news outlets that you use. You will not be formally tested on any of the material in the news stories that I will send you, but I do hope that the material in them makes its way into our classroom conversations. Have a great weekend - Dr. Nealen Avian flu! Swine flu! Now, bat flu? Last week I sent you a news article on the recent coronavirus, first described in Wuhan, China, that was emerging as a 'new' human virus, one not previously detected in humans or known to cause human disease. A week later, as you know, this remains the top health news story, and rightly so - the virus has now killed many dozens, and infected many thousands, around the globe. Viruses are a bit of an evolutionary quandary. They are tiny objects, composed of protein and nucleic acid. They are not considered to be cells, and they are not considered to be 'alive'. They are parasitic 'replicating devices' - they can only replicate when they have successfully infected the cell of a host species. And, they are designed to take-over the protein machinery of their host's cell, causing it to make many more virus particles, and to spread them. https://en.wikipedia.org/wiki/Virus Mammals have evolved with viruses throughout our history, and our immune systems contain some viral defenses, just as our genomes contain bits and pieces of DNA that may have been viral in origin. In recent years and decades, we have increasingly been aware of 'new' viruses, not previously seen in humans, that are suddenly causing human disease. Swine flu, avian flu, MERS, SARS, and others - and now, the Wuhan coronavirus. https://www.bbc.com/news/health-51237225 Why are viruses so common in mammals? Because we are really good hosts for them - lots of cellular protein machinery, warm-blooded cells which promote high rates of viral replication, dense social structure which promotes transmission. From rats to cats, bats, camels and more, each mammalian group bears its own viral load. Why do viruses move between mammal species? Two words: mutation and opportunity. As viruses mutate, they can gain or lose features that make them better, or worse, suited for particular host species (e.g., cats versus dogs). As species co-mingle, the odds improve that a virus can successfully 'make the leap' to a host of a different species, one to which it is newly well-suited. Why are so many of these novel viruses originating in Asia? Population density and food production practices. On the global scale, the U.S. is relatively sparsely populated (save our largest cities). Across the globe, it is very common for population densities to be much higher than those found here. And, high human densities require ramped-up food production. Much of food production here is commercialized and removed from the public, but again, this is a global exception. Across most of the world, food production tends to be on a smaller scale, and it tends to be much more personal - individuals tending their own animals, working with their tissues and bringing their own products to open market. Together, this density and close contact ups the risk of transmission of animal viruses to human hosts. What can we do? Addressing the inequities of education and opportunity that put some more at risk of public health diseases than others is a global problem, one that is daunting in scale. Can we immediately correct it? No, of course not. We can, however, be careful consumers, paying attention to the kinds of products we purchase, their degree of commercialization, the level of exploitation that may be attached to them. We can pay attention to climate issues, which seem to exacerbate many emerging diseases. And personally, we can practice good public health ourselves - stay up-to-date with vaccinations, follow good hand hygiene protocols, cover our coughs and our sneezes. And, we can stay informed, and help others to be informed - that is perhaps the best defense of all. I hope that, by this time next week, the spread of this coronavirus has been contained. Sincerely, Dr. Nealen Coronavirus Live Updates: Wuhan May Have 1,000 More Cases, as Death Toll Rises - The New York Times1/27/2020 Good evening all,
As I scan the science news each week, I very often encounter science news reports that are worth sending to you. Some of them are timely matches to our course content, some of them are just plain interesting, and still others are just too important to ignore. This one may fall into the last category. There is an epidemic of the 'Wuhan coronovirus' in China. And, infected individuals are known to have traveled to a large number of places outside of China, such that infections are now being detected in other countries, including here in the U.S. Worldwide, many thousands are known to be infected, and the number of deaths attributed to this virus, while still low, is rising. This is a new virus, not seen previously in humans. As viruses go, this one is not especially lethal. But, like may other viruses, it appears to be able to spread reasonable easily from person to person. And, persons infected with the virus can be asymptomatic (e.g., show no outward signs of illness) for some time, allowing them to come into contact with others before they are aware of the need to limit their exposure to others. Is there a vaccine? No, it is not possible to create a vaccine to a new virus in such short time. From where has this virus come? It has been suggested to have originated in reptiles (possible snakes), and then made the jump to human hosts. This is not completely novel, as other viruses which cause human disease (such as the HIV virus, or those causing 'swine flu' or 'avian flu') also originated in animals. Why are humans at risk from these new viruses? Because we have no prior exposure, our medical community has no ready defenses (such as vaccines). Because this virus may be appearing in humans for the first time, our immune systems have not evolved any natural defenses, either. Should you panic? In short, no. Many more people die because of the seasonal flu virus each year than are likely to suffer death from this one. What should you do: Most importantly, pay attention to the news, stay informed, and be cognizant of anyone in your circle of interaction who may recently have traveled from an area in China experiencing an outbreak. Only if cases are detected in our community will specific calls to action be issued. So, if the lethality of the virus is low, and the risk of infection is low, why should you care? It's worth paying attention because this is just the latest in a series of 'new' viruses that have emerged (most in the Asia or the Middle East, including SARS and MERS) that, while of relatively little consequence here, are severely problematic there. Imagine entire cities on lock-down, quarantine. Imagine all of the work, school, and travel that has been disrupted. And, remember, there is still much we do not know about this virus, of its origins, its ability to mutate, and spread. Ask yourself: what if it happened here? Would our U.S. health agencies be ready and able to combat the emergence of a new virus? Many feel that the answer is 'no'... The best individual defense is information, and awareness - that is why I am sending this along today. https://www.nytimes.com/2020/01/26/world/china-coronavirus.html --------------- I will occasionally pass along articles of this type during the semester. My purpose in doing so is to help you to become more aware of current physiology and health topics, and also to help you assess how you obtain your science and health news. Those of us working in science obtain our scientific news, quite often, directly from the original sources: the people conducting the studies and reporting the results. They publish their findings in science journals, or present them at conferences. Most people do not obtain their science news directly, but hear news via secondary sources, such as news releases from scientific organizations, or as science news stories from the major news outlets. These secondary reports often are then carried by tertiary outlets (smaller/other reporting sources). Along the way from source to audience, science news is normally distilled (a lot) - much of the detail is excluded or simplified, and the reports often are boiled-down to singular take-home messages, which may, or may not, be good representations of the original work. When you browse the links that I will forward, or when you access science and health news on your own, I'd encourage you to delve a little bit deeper into them, to read more than just the summaries, and to follow links back to original sources when possible. I'd also encourage you to think a little about the translation of news from source to consumer, and the reputability of the news outlets that you use. None of these news links that I send you will be represented on our course exams, but I do hope that the material in them makes its way into our physiology conversations. I'm sending this link to both my BIOL 240 lecture and lab sections, so my apologies if you receive this message twice. This first link is from the New York Times, which provides one of the best (e.g., best funded and most reliable) secondary sources of science and health news. They do limit access to only a handful of free articles each month, so I will use them sparingly. Have a great rest of the weekend - Dr. Nealen Good morning all, As we remain on-schedule, we will not meet in-person for lecture on Friday (15 Nov). I'd like instead to offer you several pieces of recent science news: We have considered issues surrounding vaping several times this terms, most recently the alarming and poorly-understood severe respiratory distress that has developed in otherwise healthy individuals who vape. After several months of investigation, our CDC (Centers for Disease Control and Prevention) have released a report that appears to identify the likely cause of his distress syndrome: vitamin E acetate, and oily compound used as a additive in some vaping products. https://www.cdc.gov/mmwr/volumes/68/wr/mm6845e2.htm?s_cid=mm6845e2_w Vitamin E and its derivatives are lipophilic (fat soluble), which allows them to interact with cell membranes more easily than most biological compounds (which are hydrophilic, or lipophobic). Multiple samples of lung tissue from persons afflicted with vaping-associated respiratory distress have revealed this compound adhering to the lung surface. If you remember our discussions on lung structure/function, we described the exchange surface between the alveoli and the capillaries of the lungs as being as thin as possible (essentially, two single-cell layers of epithelium), to allow as much gas diffusion across them as possible. Now, imagine that same surface covered with a sticky, oily residue - it's easy to see that gas exchange could be severely impaired. There may be other substances contributing to this distress syndrome, and not all experts are convinced that vitamin E acetate is the culprit. But, the evidence is accumulating, and it appears likely to be the primary cause of the cases investigated so far. https://www.nytimes.com/2019/11/08/health/vaping-illness-cdc.html If you do vape, check your products - do they list this as an additive? Can you select other materials that do not? Juul, one of the largest companies producing vaping products, recently agreed to stop making some kinds of flavored vaping products, as they and others in the industry were being accused of improper marketing toward minors: https://www.cnn.com/2019/11/07/health/juul-mint-pods-bn/index.html One young person with vaping-associated respiratory distress recently was forced to undergo a double lung transplant: https://www.reuters.com/article/us-health-vaping-transplant/michigan-boy-17-gets-double-lung-transplant-after-damage-from-vaping-idUSKBN1XN04R Vaping seems like a habit to be avoided at all costs, in my view. Our lung tissue is simply not designed to handle contact with things other than atmospheric gases. In a few years, we may look back at this as a trend that appeared, and briefly flourished, before its significant health implications were well-understood. I suspect that regulations around vaping will get tighter and tighter, and the available evidence suggests that our public health would be best served by limiting access to vaping materials and more carefully regulating their contents. Have a great rest of the week - see you on Monday for Chapter 22 (DNA Biology and Technology). Sincerely, Dr. Nealen Good morning all, As I noted in lecture on Wednesday, we remain caught-up with our lecture schedule and do not have chapter assigned for today. So, we will not meet in person for class today; instead I will offer this reading which I would like to you to consider. In our last lecture, we identified the "cell cycle" as a way to describe the normal lifespan of a cell, from its formation, through its functional life, and then its eventual end. All of our body cells are formed from mitotic cell division to begin their life, and, at the end of their functional lives, many of our cells undergo division themselves, essentially being reborn as two new daughter cells. We also identified important "checkpoints" in the cell cycle, to prevent cells from speeding through the cell cycle too rapidly. Many of our cells have functional lives of months to years, and without these checkpoints, they would otherwise just divide rapidly into new cells. As we noted, failure to stop at these cell cycle checkpoints can lead to tumors caused by uncontrolled growth; some tumors can become cancers, invading otherwise normal tissues and causing them to become cancerous as well. As you know, cancer is one of the primary causes of human mortality. We experience a variety of cancers: some are slow to progress, others very rapid; some are essentially benign while others are very deadly; some are highly invasive and others less so. The diversity if cancers we experience and the diversity of tissues that they strike represents one the of the primary difficulties in treating cancer: there is no single cure, for cancer is very diverse in its many forms. That's not to say that there aren't standardized treatments. Most hospitals have oncology boards that carefully document each occurrence of cancer, and they typically made treatment decisions based upon consultation among a team of physicians, including oncologists, radiologists, surgeons, and others. Much of their decision-making is based upon care standards that have been developed by national and international cancer agencies, such as our own American Cancer Society, which suggests treatment guidelines for the different forms of cancer. Still, we know all too well that curing cancer is difficult, and sometime impossible. The best one can hope for is to eliminate the cancerous tissue to the point at which is cannot be detected, but that is no promise that every cancerous cell has been removed, nor that it cannot re-appear. Because of the burden cancer poses to society, there are many federally-funded research groups investigating potential treatments. These include
Of course, many of the latest treatments combine multiple approaches, such as using immune cells to target delivery of cytotoxic drugs directly to cancer cells. In the news this week is report of a promising new approach to treating some kinds of cancer, based upon a metabolic starving of cancer cells. Cells that are rapidly dividing (such as those within a tumor or a cancer) are metabolically very demanding, needing large amounts of fuel. Scientists have developed methods to prevent cells from using glutamine (a glucose-like fuel source), to successfully prevent cancer growth. But, earlier formations of this treatment caused widespread side effects, because the cancer cells were not the only ones being starved of fuel. In this latest test, the scientists successfully "handcuffed" an inactive form of their drug to allow its focal delivery to cancer cells, where it was "unhandcuffed" into an active form by cancer cell enzymes. There it successfully prevented cancer growth. Even better, this new treatment actually improved immune T-cell function, providing an immunological boost to cancer elimination as well. These initial studies, done in mice, were very promising. While the road from animal studies to human uses is often long and unsure, this could mark the beginnings of a new generation of cancer treatments that are improved in their focused targeting as well as in their effectiveness at cancer elimination. https://www.sciencemag.org/news/2019/11/revamped-cancer-drug-starves-tumors-mice We'll talk more about cancer in our upcoming lectures, and I hope that this article will put some of the lecture material into practical context. Cancer touches many families, and does not discriminate by race, class, knowledge, or upbringing. May your generation be the one that finally reduces the impact that it has on our individual and our public health. Have a great weekend - see you on Monday. Sincerely, Dr. Nealen Good morning everyone, Last week I sent you a news report about the prospect of "sugar taxes", extra monetary tax levied against sweetened drinks as a way to reduce their consumption and to (hopefully) induce some improved health in the persons who might normally consume too much sugar in their diets. The article that I sent you last week considered some of the potential benefits, and potential difficulties, of implementing such taxes. It also described the limited amount of data available thus far, suggesting that it is still too early to know whether these kinds of taxes lead to health improvements. In this news this week is report of a newly-released study on this very topic. Here, researchers followed the health of a focal group of 200+ people at the University of California-San Fransisco medical school, where a full ban on the sale of sweetened drinks has been in effect. Researchers report improvements in several subject health measures, including reduced waist size, less belly fat, and improved response to insulin. They suggest that these changes were directly a function of reduced sugary drink consumption in these subjects. https://www.nytimes.com/2019/10/28/well/eat/sugary-drink-soda-ban-health-medical-center.html Note that this study described subjects under a workplace ban on the sale of sweetened drinks, not those under a "sugar tax". Here, subjects could purchases sweetened drinks elsewhere, or bring them from home, but could not purchase them at their workplace. This is likely to have a larger effect on consumption than a sugar tax itself, but it does suggest that the benefits of lowering the consumption of sweetened drinks is a very worthwhile goal. The available data suggests that most of us consume too much refined sugar (in some form), which suggests that most of us would benefit by reducing our sugar intake. As we have seen many times during the term, our health depends heavily on the choices we make. Hope that you are enjoying the weekend - see you tomorrow. Dr. Nealen Good evening all, As I noted in lecture on Wednesday, we remain on-schedule with out lecture chapters, and do not have a chapter scheduled for tomorrow (Friday 25 Oct). So, I would like once again to propose that we do not meet in person for lecture tomorrow, and ask instead that you consider the reading that I am forwarding here. In our last lecture on the endocrine system, we noted the central role of the pancreas and its hormones in the regulation of blood glucose ("blood sugar") levels. When levels of blood glucose rise (such as when we are absorbing digested sugars into our bloodstream after a meal), the hormone insulin is released by the pancreas. Insulin causes our cells (especially liver and muscle cells) to uptake glucose - that is, to take glucose out of the bloodstream and move it into cells by means of membrane transporters. This allows cells to have glucose available for fuel, and also allows cells to store the excess glucose for later use. On the flip side, when our blood glucose levels decline (such as when we are several hours past a meal and done absorbing nutrients), other cells in the pancreas release the hormone glucagon, which causes our cells (especially liver and muscle cells) to release some of their stored glucose. Together, the use of the two hormones allows us to maintain a relatively even profile of blood glucose levels. As we discussed yesterday, when blood sugar levels are not well-controlled, diabetes may result. The primary symptom of diabetes is high (and poorly controlled) blood glucose levels. This causes a number of immediate effects, such as excess urination, thirst, and excessive fat metabolism. Over the long term, high levels of blood glucose are very damaging to our tissues, particularly through scarring of the inner lining of our blood vessels. This can lead to the failure of organs with extensive capillary beds (such as the retina of the eye, and the kidney), and has negative effects on circulation in general, especially in the lower periphery. Persons with uncontrolled blood sugar often suffer poor wound healing (especially of the feet), which can lead to infections and, in some cases, require amputation. In lecture, we distinguished the two general types of diabetes as well. "Type I" diabetes occurs when our own immune system causes the destruction of the insulin-producing cells of the pancreas. This is classified as an auto-immune disorder, as the disease stems from a problem with the immune system. Type I diabetes is often called "juvenile diabetes", because it is typically first diagnosed in one's youth. It can be treated (usually successfully) with injections of insulin - daily, often multiple times. Insulin pumps can also be used - these are small, battery powered pumps that infuse gradual, small amounts of insulin into a catheter. They are expensive and require maintenance, but are effective solutions for many. "Type II", or "adult onset diabetes" is more challenging. It tends to appear in people with a combination of risk factors: obesity, poor diet, little exercise. Over time, the cells of their body gradually become resistant to insulin, and stop responding to it. Their pancreas produces normal amounts of insulin, but it is ineffective - blood glucose remains elevated, cells become starved for sugar fuels, and metabolize other fuels (mostly fats). Tissue damage accumulates because of the persistently elevated blood glucose levels. Additional insulin (injections) can help somewhat, but the most effective treatment is improvements in diet and exercise. Some people can almost completely reverse their condition through these lifestyle changes, and nearly everyone can benefit at least somewhat from them. There is a lot of biology associated with diabetes: its causes, effects, and treatments. There also is a lot of sociology to it as well. Diabetes strikes populations very unevenly, and impacts populations of relatively poorer socioeconomic levels most severely. This is believed to be due to a number of factors, including reduced access to high-quality food, more-restrictive employment and familial responsibilities that limit time to exercise, and less access to good information about health. It has also been suggested that food corporations specifically target these populations with advertising and vendors for "fast food", including soft drinks ("soda", or "pop", depending upon where you were raised). As a food, soda is of very low quality. It is mostly water, but the other primary ingredients are sugar, and often caffeine. It is also quite acidic, and has quite damaging effects on our teeth. So, why do we buy/drink it? We do so at least in part of because of very successful, and very prominent, advertising, which has allowed some soda companies to develop enough clout that they can contractually deliver soda to schools, hospitals, corporations, and even cities. Think back to your middle- and high-school education: did soda vending machines exist in your school? Were fountain drinks available over the counter in the cafeteria? For most of us, the answer to these questions is "yes". Do you buy bulk quantities of soda? Do you see others around you who do? Again, for most of us, the answers here are "yes" as well. In recent years, public health experts have recognized the dangers of over-consumption of soda, and more importantly, the danger of exposure to it in our youth. Too often, adolescents develop a "soda habit", and maintain it into adulthood. This, in combination with other lifestyle choices, has led to skyrocketing rates of juvenile obesity. Even more alarming, "adult onset" diabetes is now diagnosed in adolescents at alarming rates. So what can be done? Well, the debate rages, because to eliminate soda from communities and diets is not really an option. Soda companies are large, and powerful, and they have an avid user base that wants their products. This is a situation similar to that faced years ago with the tobacco industry: large and powerful corporations, well-paid lobbies, a desirous user base, and mounting evidence of the dangerous health effects of the product. Here, too, numerous solutions were discussed and tried. One of the remedies that seemed to be most effective was to implement larger and larger taxes on tobacco, to the point at which fewer people were willing, or able, to financially support their tobacco habit. Because of the success of this strategy to reduce tobacco usage, we now live in an era of the "soda tax". The idea here is the same: if a popular consumer product is legal, but unhealthy, tax it in order to reduce the number of people using it, and/or the amounts that they use. This remains a controversial idea. Why should companies producing a legal, desirable product be punished? Is this ethical? Does this not also punish the people that work for them, and their suppliers, accountants, and all of the other people who work in associated jobs? Does this also punish consumers of relatively lower income unfairly, because they would be the ones least likely to be able to afford a price increase? With soda, too, the application of a tax is more complicated. Tobacco and alcohol are relatively uniform in how they are packaged and purchased, but sugary drinks exist across the spectrum (from soda, to sweetened milk, to orange juice and yogurt). Wait -- aren't milk, orange juice, and yogurt good for us? Well, yes, but less so if they have a lot of added sugar. Should they be taxed less than soda, because they are relatively more healthy? What about sugary cereals and granola bars? What about foods with artificial sweeteners? The lines are less clear in this current health debate. The news report I am forwarding describes a recent assessment of the effectiveness of "sugar taxes". Dozens of other countries, and multiple large cities in this country, have imposed this tax. They have existed for a relatively short time, so there is much yet to be learned about them. They do appear to cause a drop in soda consumption, but whether that translates into improved health of the population is still to be determined. Not surprisingly, the soda companies have responded aggressively, with a variety of tactics. This battle is far from settled. http://blogs.discovermagazine.com/crux/2019/10/22/do-soda-taxes-actually-work-heres-what-the-science-is-telling-us/ The next time you are at the grocery store, ask yourself if you are planning to put soda into your cart. And, look around: how many people do? It's common to see people pushing shopping carts with 6-packs of bottled soda (often multiple of them) draped over the edges of the cart. This behavior didn't exist 10 years ago! Have the bottles changed to make this more convenient? Or are we buying more? Our fast food restaurants and convenience stores offer *enormous* fountain drinks - 30, 40, even 50 ounces at a time! Does anyone rally need that much soda at once? On this, and all of our topics, stay informed. Healthy habits require good information, and wise choices. There is plenty of information available on the health aspects of soda and its social implications. Be wise shoppers and consumers! And, have a great weekend. See you on Monday for Chapter 17. Sincerely, Dr. Nealen Good morning all, During our recent EMG lab, we considered muscle structure/function, and how muscle strength can be improved through enlargement of muscle fibers. We also noted that testosterone can support the development of larger muscles in both men and women. In the news this week is a report confirming that testosterone improves muscle and athletic performance in women, along with news of a strict limit on testosterone in female athletes being imposed by a track-and-field regulatory body. Testosterone is a potent steroid hormone, produced in abundance by the male gonads (the testes). Testosterone is also found in women. The female gonads (ovaries) do not produce testosterone directly, but do produce several estrogens, which can be converted to testosterone by enzymes (especially in the brain). Both sexes also produce other androgens (male-typical hormones) in the adrenal glands, which also can be converted into testosterone. So, we tend to think of testosterone as a 'male hormone', but the reality is not so simple. Both women and men have circulating testosterone, although men typically have levels that are 10-30x higher that those found in women. But, here too, our simplistic and convenient categorizations are not always reflected in reality. While men typically have much more testosterone in circulation than do women, the range of variation in each gender is large. What of women who produce unusually large amounts of testosterone? Will that give them a muscular and a competitive advantage in sporting events? The anecdotal and the experimental evidence say that it will. It is convenient to think of all persons as being purely binary in terms of their sex, such that all aspects of their sexual make-up (genetic sex, physical sex, physiological sex, gender identity) align to be either purely female or purely male, but the reality is, as always, more complicated. Persons of differential sexual development may not be perfectly aligned in all of their sexual characteristics, causing them to have characteristics which are not purely 100% typical of one gender or another. Apart from the social and physical challenges this poses, how such individuals can be evaluated in regulated sporting events recently has come into question. The most notable case has been that of the South African athlete Caster Semenya, a multi-medal winning foot race champion who has repeatedly been sanctioned because her testosterone levels are higher than the thresholds set for female athletes. And what of athletes that are making a gender transition? Their testosterone levels are highly variable, and may fall within the male-typical or the female-typical range. Should they be barred from, or limited in, participation in sporting events? These are important issues, beyond sporting regulation. Most aspects of society long have been male-biased, and it is becoming increasingly apparent that we suffer because of this. In science, it has become very clear that work done largely on male physiology serve females poorly. For decades, the standard experimental models for human physiology have been male mice and rats. Only one gender was used in order to reduce experimental variability. We long have known of differences in the female and male reproductive systems, but we never really appreciated how their influences translate into other systems (including the muscular system). But, now we are learning how surprisingly different male and female physiology outside of reproductive systems can be. And, the fact that this recent study of testosterone supplements in women was one of the first of its kind suggests that we have a lot of catching-up to do: https://www.theguardian.com/science/2019/oct/15/testosterone-boosts-womens-athletic-performance-study-shows There is much to be learned about differences in female and male physiology and their implications for our health and well-being, and our scientific community is finally waking up to this fact. How the sporting community deals with the complexities of our physiology is of relatively little importance, perhaps. But the issue of equality in general, in science, health, and society, is one that recent generations have failed to properly address. May your generation be more open, more mindful, and more egalitarian. Have a great weekend - Dr. Nealen |
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