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Autoimmune Disease, Evolution, Genetics, Infectious Disease

Humans share history – and a fair amount of genetic material – with Neanderthals

If you have found yourself inexplicably offended by Geico’s “caveman” commercials, new research may have an explanation: that most humans share up to 4 percent of their genes with Neanderthals.

In 2010, scientists published the incomplete-but-functional Neanderthal genome. The finding has been an understandably hot topic for geneticists. As new discoveries about this genome arise, it becomes increasingly clear that the Neanderthals, a species that died out about 30,000 years ago, played a critical role in human history – and the contemporary human genome. It seems that Neanderthals interbred with humans, probably during their migration out of Africa (which may explain why Africans don’t share nearly as many genes with Neanderthals as, say, Europeans), permanently altering our genome for the better.

Gene-by-gene comparisons between the Neanderthal and human genomes suggest that interbreeding occurred around 65,000 – 90,000 years ago. This is consistent with archeological finds pinpointing early human migration out of Africa to around 50,000 – 100,000 years ago. As researchers mine the Neanderthal genome, the effects of this interbreeding surface. Stanford graduate student Cory McLean, for example, found that Neanderthals share some of the genetic deletions that differentiate humans from other primates.

Interbreeding is also partially responsible for some of our important disease-fighting genes. According to Stanford immunogeneticist Peter Parham, PhD, interbreeding endowed humans with the genetic diversity that makes our immune systems so very functional.

Even the differences between Neanderthal and human genomes are historically revealing. Neanderthals lived in small communities of hunter-gatherers, whereas human populations tend to form larger groups, which would explain why Neanderthals lack certain forms of genes that protect humans from epidemic diseases like measles. The fact that very little autoimmune disease existed in Neanderthals (they lacked, for example, the gene variants linked to celiac disease) suggests that these human-specific defensive genes may also be linked to autoimmune diseases. This information could help scientists identify when autoimmune disease arose in humans.

Future research on the Neanderthal genome promises to provide further fascinating insights into human genetic history and, surely, some touching tales of the inter-species love that made us who we are today.

Previously: Roots of disease may vary with ancestry, according to Stanford geneticist and Open-source encyclopedia of human genome’s functional elements in the works
Via Nature News

Cardiovascular Medicine, Emergency Medicine, Health Policy, Stanford News, Surgery, Transplants

Man receives life-saving transplant thanks to health-care reform and a truck

Man receives life-saving transplant thanks to health-care reform and a truck

In the most recent issue of Inside Stanford Medicine, my colleague tells the almost-difficult-to-believe story of Milton Gilmer, a man who literally drove himself to the hospital while having a heart attack.

Gilmer had been diagnosed with pulmonary hypertension, a disease that causes abnormally high blood pressure in the lungs and heart, in 2006. In 2010, his condition had reached a critical point, and it became clear that he would need a heart and lung transplant. Gilmer’s health insurance initially refused to pay for the operation, since the cost exceeded the medical plan’s lifetime dollar limit for this kind of procedure. Luckily for him, the Affordable Care Act that passed in March 2010 eliminated lifetime benefit limits.

Health-care reform was something of a deus ex machina for Gilmer – and it didn’t come a moment too early. In early February 2011, days before Gilmer was scheduled for a heart-lung transplant at Stanford Hospital, a pre-transplant coordinator received a phone call from Gilmer informing her that he was having a heart attack. When she told him to hang up and call 911, Gilmer told her that he was already at the hospital. True to his independent Montana roots, he had driven himself in his truck. (Don’t try this at home, kids.)

Gilmer successfully underwent surgery on February 8. He’s happy to be back on his Montana ranch home with his wife, Donna.

Aging, Patient Care, Research

Minimally increased mobility can reduce duration of hospital stay

According to an Israeli study published today in Archives of Internal Medicine, geriatric patients who walk around while at the hospital may reduce the duration of their stay. The study surveyed 485 participants aged 70 and up and took patients’ health status into account. The University of Haifa reports:

The muscle’s ‘reserve capacity’ can decompose quite quickly in older people. If they shift from a mode of mobility – even if it was minimal – to a state of almost complete immobility, and even for just a few short days of hospitalization, they could very quickly lose their muscle ‘reserves’, resulting in more difficulties functioning and other complications. … “Given the over-occupancy of many hospitals, this finding can be of great importance,” [researchers] concluded.

Clinical Trials, Ethics, FDA, Health Policy, Pediatrics

Anti-venom drug gains FDA approval despite clinical trial tribulations

Despite significant difficulties, a new anti-venom product that treats the pain (and the neurological side effects) of a bark-scorpion sting was approved by the Food & Drug Administration after testing in a tiny clinical trial.

Bark-scorpion stings, which are potentially lethal, can lead to severe pain, extreme nausea, blurred vision and breathing problems in children, according to a Nature Spoonful of Medicine blog post. The only anti-venom product that existed before its invention did not have FDA approval, and, because it was not highly purified, often caused anaphylactic reactions. What’s more, its production ended in 2000, and supplies in hospitals were dwindling.

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Genetics

The Genetic Music Project highlights the dramatic beauty of the genome

ScienceRoll reported today on the Genetic Music Project, an open-source art piece created by graduate student Alexandra Pajak. The Genetic Music Project creates music based on genetic sequences. Ways to translate genes into music range from the simple (say, assigning a single note to each nucleotide, resulting in a song comprised of 4 notes) to the complex, as the website explains:

Some of the fun ways I think this could be expanded would be to take on two characteristics delineated in the genetic markers, assign different instruments to each gene marker and different notes to the nucleotides within each genetic marker and then play them in parallel. In that way you can have multiple instruments, and more than just four notes. Indeed, since all life is based on the combination of different four-note codes on top of other four-note codes the combinations approach infinity.

Disregarding the aesthetic quality of the musical outcome – which, like all art, is subjective – the project highlights the complex beauty of the human genome and its potential, even at its scariest.

Mental Health, Neuroscience, Research

Brain’s inability to create new neurons can lead to depression, unmanageable stress

Depression is a prevalent disorder whose origins (like those of so many other mental diseases) are nonetheless shrouded in mystery. A new study published in Nature has identified one potential cause of depression. The study involved mice whose hippocampi were unable to generate neurons.

The hippocampus is a portion of the brain that is particularly vulnerable to stress, as a Booster Shots blog entry by Karen Kaplan explains. Mice whose hippocampi couldn’t grow new neurons acted like other mice during normal conditions. However, under stressful conditions, these mice were unequipped to handle the stress and became depressed, exhibiting some of the hallmark symptoms of mouse depression (e.g., losing their taste for sugar water). Their stress-hormone levels remained high for much longer than those of normal mice exposed to the same stressors.

These findings are consistent with past research showing that antidepressants trigger neuron growth in the hippocampus, which may be partially responsible for their depression-easing effects. A better understanding of the delicate relationship between stress and depression is an important tool for producing more effective treatments.

Previously: Depression and anxiety linked to early digestive disturbance in Stanford study and Antidepressants don’t improve all symptoms of depression

Medicine 2.0

Medicine 2.0 organizers offer a need-based discount for ePatients

The organizers of the Medicine 2.0 conference at Stanford have just announced a scholarship program offering ePatients significant discounts off the conference registration fees. Interested ePatients should apply for the scholarship by August 10.

More news about the Medicine 2.0 conference at Stanford is available in the Medicine 2.0 category.

Chronic Disease, Health Costs

Polypills could improve drug compliance, preventative medicine

A peer-reviewed article by NYU medical student Jonathan Levanthal over at Clinical Correlations makes a convincing argument for polypills – that is, a combination pill that could be administered in place of multiple medications – as a means of avoiding drug noncompliance for the chronically ill. Polypharmacy, Levanthal argues, is a leading cause of this noncompliance:

…a poorly controlled diabetic with other medical comorbidities must not only remember to take numerous pills at different times of the day in relation to meals, but also to inject insulin subcutaneously. The patient must also do fingersticks to monitor blood glucose and then make further dietary or medication adjustments accordingly. The regimen is laborsome. It is no wonder that so many of my patients are noncompliant with their medications.

Levanthal also proposes a preventative polypill containing, say, aspirin, folic acid, antihypertensives, and various other goodies, to be administered to adults over the age of 55. He cites a study suggesting that this “magic bullet” pill could prevent 3.2 million cases of coronary artery disease and 1.7 mission cases of strokes over 10 years.

Levanthal recognizes the potential issues of such a pill (the most obvious being that adverse reactions to one of its elements would render the entire regimen-containng pill unusable or ineffective). However, the simplicity that a polypill would bring to chronically ill people - not to mention the potential savings - makes the proposal one worth considering.

Previously: A pill that spills the beans and No co-pays mean more people take their medicine
Photo by Dvortygirl

Obesity, Pediatrics, Research

BMI can oversimplify weight categories by ignoring natural fluctuations

BMI can oversimplify weight categories by ignoring natural fluctuations

BMI is a quick-and-dirty formula for categorizing individuals as “underweight,” “healthyweight,” “overweight,” or “obese,” based on height and weight – but it’s far from perfect. Weight, like most elements of health, is a spectrum, not a series of boxes. Gaining or losing one pound could cause a person to skip between the “healthy” and “overweight” categories if BMI is the only measure taken into account. Not only does this mean that two equally healthy people whose weight differed by a single pound could be subject to very different treatment healthwise – it also ignores factors like daily height and weight fluctuations.

This morning, Obesity Panacea hosted a post by PhD student Ash Routen, whose recent research involved calculating schoolchildren’s BMIs based on height and weight measurements taken throughout the day.

Routen measured 74 U.K. children’s heights and weights in the morning, and then measured them again that same afternoon. He found that all the children were shorter in the afternoon, and that only the girls were heavier. Depending on the percentiles determining the various weight status categories (population-monitoring versus clinical cutoffs for the various categories), over the course of the morning either one or two girls has shifted from “healthyweight” to “overweight,” and one moved from “overweight” to “obese.”

These verbally drastic shifts in categorization resulted from minimal, natural fluctuations in height and weight. Routen concludes that studies of schoolchildren using BMI as a tool for determining health should be standardized, all taking place at the same time of day. I would add that actually observing people to see how healthy they look and taking factors like body fat versus muscle mass into account shouldn’t be underestimated – especially when it comes to categories with such potentially harmful cultural and medical baggage.

Photo by cogdogblog

Cancer, Genetics, Research, Women's Health

Researchers take a step towards understanding the genetics behind breast cancer

Researchers take a step towards understanding the genetics behind breast cancer

Scientists at the Institute for Cancer Research (ICR) in London have developed what is being called an “encyclopedia of genes” associated with breast cancer – something they hope will help with the quest for new treatments. As a Cancer Research UK article explains:

[The researchers] used a lab technique called high-throughput RNA interference screening to identify genetic faults that drive the various forms of breast cancer.

Tumour cells contain a large number of genetic alterations. In the past, researchers have had problems designing targeted drug therapies as it can be difficult to determine which faults fuel cancer tumour progression and which are coincidental.

The research, published online in the American Association of Cancer Research journal Cancer Discovery, can now be used by scientists around the world to develop drugs that will target the faulty genes most associated with breast cancer.

The method, which was designed to provide a more targeted, personalized approach to cancer therapy, may also apply to other cancer types if validated.

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