tag:blogger.com,1999:blog-28393950690776497432024-03-06T15:03:25.629-05:00MJ's Human Biology Blog"MJ's Human Biology blog" highlights recent items in the news or in scientific journals that cover new findings and hot topics relevant to the teaching of human biology. The host is Dr. Michael Johnson, author of Johnson's Human Biology: Concepts and Current Issues.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.comBlogger779125tag:blogger.com,1999:blog-2839395069077649743.post-79643911020997241602018-06-20T11:06:00.000-04:002018-06-20T11:06:35.761-04:00Should Labor be Induced in Extra-Long Pregnancies?Compared to normal-length pregnancies, pregnancies that go on too long carry a slightly greater risk of fetal death at or near the time of birth. For that reason, physicians sometimes recommend that labor be induced when a pregnancy has gone on longer than normal. But induction of labor may also entail a small risk, especially if there is no sign of impending spontaneous labor. Which is the lesser risk? <br /><br />To find out, <span style="color: blue;"><a href="http://www.cochrane.org/CD004945/PREG_induction-labour-women-normal-pregnancies-or-beyond-term" target="_blank">researchers combed all the available data</a></span> from previous studies of inducing, or not inducing, labor after unusually long gestation (usually 41 weeks). In all, they reviewed 30 studies involving a total of over 12,000 women in 14 countries. <br /><br />The results? Inducing labor after 41 weeks resulted in fewer infant deaths. It also resulted in fewer caesarean deliveries, though on the other hand it did result in more assisted (operative) vaginal births. All in all, induction of labor after 41 weeks of gestation appeared to be a good choice. However, it was not determined in this study whether there is an optimal time of induction - should it be at 41 weeks, or 42, or even 43? <br /><br />Based on this analysis, women who experience an extra-long gestation can safely consider induction of labor as an option.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-61156869917596814122018-06-13T06:58:00.000-04:002018-06-13T06:58:03.324-04:00Cinnamon-Flavored e-Cigarettes May Pose a Health RiskThe naturally occurring organic compound that gives cinnamon its characteristic flavor and odor is called cinnamaldehyde. It's approved by the FDA as a food additive and is considered to be completely safe in foods. More recently, it's also been used as a flavoring in e-cigarettes, but that just may be a problem. Recent preliminary research suggests that cinnamaldehyde may be harmful when inhaled, according to a <a href="https://consumer.healthday.com/cancer-information-5/electronic-cigarettes-970/cinnamon-flavored-e-cigs-may-bring-lung-dangers-study-734202.html" target="_blank"><span style="color: blue;">report in HealthDay</span></a>. <br /><br />In the research, which must be considered preliminary because it has not yet been published in a peer-reviewed journal, human lung cells in cell cultures showed reduced cilia activity when exposed to cinnamaldehyde either in e-liquids and e-liquid vapors. In intact humans, lung cell cilia are responsible for helping to clear the lungs of mucus, dust, and bacteria. If cinnamaldehyde affects the activity of lung cell cilia in intact lungs the same way as it does in cell cultures, it's just possible that it could increase the risk of lung infections. <br /><br />To be clear, though, an increased risk to your health of vaping cinnamon-flavored e-cigarettes has not yet been proven. So YOU have to decide whether the potential of risk is worth it, if you're ever choosing e-cigarette flavors.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-69439548625086647922018-06-05T15:25:00.000-04:002018-06-05T15:25:42.984-04:00Not All Women With Breast Cancer Will Need ChemotherapyNearly 60,000 women a year will benefit from a <span style="color: blue;"><a href="https://www.nejm.org/doi/full/10.1056/NEJMoa1804710" target="_blank">recent study</a></span> which shows that not all women with breast cancer should undergo chemotherapy, according to <span style="color: blue;"><a href="https://www.nytimes.com/2018/06/03/health/breast-cancer-chemo.html" target="_blank">an article</a></span> in the <i>New York Times</i>. The women who don't benefit from chemotherapy are a subset of women with breast cancer who: 1) are in the early stages of breast cancer, 2) are sensitive to estrogen, 3) test positive for a protein called HER2, and most importantly, 4) have a mid-range score on a genetic test that looks for various genes involved in cancer recurrence. The genetic test, which is now widely available, costs about $3,000.<br /><br />Cancer is complicated. The newest findings are part of an ongoing effort to fine-tune cancer treatment to each patient's specific situation, so that the patient receives the very best treatment while reducing the risks associated with unnecessary chemotherapy.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-83602858205642813562018-05-23T11:39:00.000-04:002018-05-23T11:39:09.851-04:00California's Death With Dignity Law is Declared UnconstitutionalIn 2015, California became the fourth state to pass legislation designed to allow terminally ill patients to end their own life under certain prescribed conditions (see this blog, Sept 17, 2015). The law, called the End of Life Option Act, has always been somewhat controversial. And last week, opponents of the law won a battle in court when a Superior court judge declared the law unconstitutional, according to <span style="color: blue;"><a href="http://www.latimes.com/local/california/la-me-ln-end-of-life-becerra-20180521-story.html" target="_blank">an article in the <i>LA Times</i></a></span>. <br /><br />On what grounds is the law unconstitutional, you might ask? It turns out that the judge's decision had nothing to do with the law itself; his decision was based solely on the fact that the law was passed during a special session of the legislature devoted solely to health care issues. The judge declared that the law was not a health care issue, and so it was unconstitutional to pass it during the special legislative session. <br /><br />Really? Not a health care issue when a terminally ill patient is in excruciating pain? California's Attorney General has already filed an appeal to the judge's ruling with the 4th District Court of Appeal. He's also asked that the law stay in place while the matter is under appeal. <br /><br />The matter could end up with the Supreme Court. Or, the law might need to be considered all over again in a regular session of the legislature. <br /><br /> Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-34057265286534419172018-05-21T22:03:00.000-04:002018-05-21T22:03:34.484-04:00Ebola Outbreak Spreads to a Nearby CityHealth officials at the World Health Organization <span style="color: blue;"><a href="http://www.who.int/news-room/detail/17-05-2018-who-concerned-as-one-ebola-case-confirmed-in-urban-area-of-democratic-republic-of-the-congo" target="_blank">(WHO) reported this week</a></span> that the most recent Ebola outbreak, which began in a remote village of the Democratic Republic of the Congo (see this blog, May 12, 2018), has spread to a nearby city of over a million people. Only one case of Ebola has been reported in the city so far, but the fear is that the outbreak could spread more quickly now, making containment more difficult. In a city, tracking down and potentially vaccinating every individual who has been exposed to a patient becomes much more difficult. <br /><br />Keep your fingers crossed. We'll be watching this outbreak closely.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-77901857609509837172018-05-13T07:40:00.002-04:002018-05-13T07:40:42.102-04:00How DNA Analysis Led to the Golden State KillerMore than 30 years after his last crime, a suspect has finally been arrested in the infamous Golden State Killer case. The suspect, a 76-year-old former police officer named Joseph DeAngelo, is believed to have committed over 50 rapes and 12 murders in California between 1976 and 1986. How did police solve a crime spree that ended more than 30 years ago? (Drum roll, please.....) DNA analysis, that's how! <br /><br />It turns out that police had DNA samples from the Golden State Killer, collected from several of his crimes many years ago. But they had no suspects to try to match them to. Companies like 23andMe have lots of DNA samples, but they are not searchable by the public or the police. However, there's a small company called GEDmatch that analyzes DNA samples and makes them available for free for research purposes. Police detectives searched the GEDmatch database recently, and identified a DNA sample that was close enough to the killer's DNA that it had to belong to a relative (for more on how that works, <span style="color: blue;"><a href="https://arstechnica.com/tech-policy/2018/04/gedmatch-a-tiny-dna-analysis-firm-was-key-for-golden-state-killer-case/" target="_blank">see this article</a></span>). Studying that person's family tree led them to Joseph DeAngelo as a possible suspect in the Golden State Killer case. <br /><br />To find out for sure, the police covertly collected a DNA sample from Mr. DeAngelo (it wouldn't be hard to do - we discard DNA every day on coffee cups and soda cans, for example). It was a match to the killer's DNA samples that they'd had on file for 30 years! <br /><br />Case closed, finally.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-16263662080338219012018-05-12T07:44:00.000-04:002018-05-12T07:44:17.857-04:00Another Outbreak of EbolaThe Ebola virus that killed more than 11,000 people in four African countries in 2014-2015 has <span style="color: blue;"><a href="http://www.who.int/news-room/detail/08-05-2018-new-ebola-outbreak-declared-in-democratic-republic-of-the-congo" target="_blank">broken out again</a></span> - this time in a remote village in the Democratic Republic of Congo. So far, 17 people have died from the newest outbreak, including one nurse who was caring for victims. <br /><br />The 2014-2015 outbreak was so deadly because the countries involved and various medical aid agencies were slow to respond. This time around, health officials are taking no chances. The World Health Organization is mobilizing a rapid response force that includes medical experts, equipment, and medical supplies, including a new Ebola vaccine. The affected area is just three hours away by road from a city of over a million people. If the virus reaches the city, containment of the outbreak could become much more difficult. <br /><br />From past experience, health officials believe that by attacking viral disease outbreaks early and hitting them hard, outbreaks can be stopped in their tracks before they can spread very far. It worked (minus the new vaccine) in stopping a previous Ebola outbreak in the Democratic Republic of Congo in 2017. Let's hope it works again.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-12263594239999295652018-05-06T09:02:00.001-04:002018-05-06T09:02:29.170-04:00Testing Zika VaccinesHere's a question for you. Suppose that you had been working on a vaccine for the Zika virus, and now you have what you think might be a good one. How are you going to prove its safety and effectiveness? <br />
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Testing your vaccine for safety would be relatively easy; you'd give it to just a few people at first, and then to dozens, then hundreds of volunteers until you could prove that it was free of dangerous side-effects. But the real difficulty would be to prove that it is effective; that is, that it actually would prevent a Zika virus infection. Zika infections are relatively rare, even in Zika-infections regions. And you can't just test the vaccine on the persons who do become infected; vaccines have to be given <i>before</i> an infection occurs, not after. <br />
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So here are your options: 1) Administer the vaccine (or a placebo) to tens or even hundreds of thousands of healthy people in a Zika-infected region, so that just by chance you will have vaccinated a few people who will contact Zika at some time in the future, and then wait, or 2) administer the vaccine (or a placebo) to perhaps a few hundred volunteers and then deliberately infect them with the Zika virus. <br />
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Because Zika infections are relatively rare, the first approach is likely to be prohibitively expensive, time-consuming, and might never achieve the desired result. That's why <span style="color: blue;"><a href="https://www.nytimes.com/2018/04/20/health/zika-study-ethics.html" target="_blank">researchers are proposing</a></span> the second approach; deliberately infecting vaccinated and unvaccinated volunteers with Zika. The researchers argue that a Zika infection, like the flu or a cold, is a relatively minor illness for an adult. The real danger is to a woman who is pregnant, because a Zika infection during pregnancy can lead to serious birth defects in an infant. For that reason, the researchers say that any women in the proposed study would have to agree to avoid pregnancy for the duration of the study. <br />
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Still, some ethicists are queasy about the proposed study. Accidents (including unplanned pregnancies) happen. And this study would be of no benefit whatsoever to the persons who would choose to volunteer; they'd have to be doing it solely out of altruism. <br />
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What do YOU think?<br />
<!--EndFragment-->Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-47792599281894536442018-05-05T16:32:00.000-04:002018-05-05T16:32:12.758-04:00Hawaii Passes a Death With Dignity Law<span style="color: blue;"><a href="http://www.staradvertiser.com/2018/04/05/breaking-news/gov-ige-signs-bill-legalizing-medical-aid-in-dying/" target="_blank">Hawaii</a></span> becomes the sixth state (plus Wash. D.C.) to pass a Death With Dignity law, permitting terminally ill persons to choose to end their own life in certain situations. Like the laws in other states, Hawaii's law requires agreement of two doctors that the patient is mentally sound and has less than six months to live. If such conditions are met, the patient is prescribed a lethal dose of a medication (usually a powerful barbiturate) that they may use (or not) at their own discretion. <br /><br />Death With Dignity laws continue to gain traction. One reason is that both a majority of Americans and a majority of doctors now support them. High-profile cases such as that of Brittany Maynard (see Johnson's <i>Human Biology; Concepts and Current Issues</i>, 8e. p. 480) have kept end-of-life issues in the public eye. And it helps that there has been no evidence of misuse or abuse of such laws in the first few states that passed them. <br /><br />The number of people who choose to take advantage of Death With Dignity laws remains small. <span style="color: blue;"><a href="http://www.oregon.gov/oha/PH/PROVIDERPARTNERRESOURCES/EVALUATIONRESEARCH/DEATHWITHDIGNITYACT/Documents/year20.pdf" target="_blank">In Oregon</a></span>, which has had a Death With Dignity law since 1997, only 218 people requested lethal prescriptions in 2017 and only 143 people used their prescriptions to end their lives. Most were cancer patients over the age of 65.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-67956466106864526242018-04-26T18:46:00.002-04:002018-04-26T18:46:42.946-04:00The FDA Tackles the Marketing of e-Cigarettes to YouthsThe <span style="color: blue;"><a href="https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm605432.htm" target="_blank">FDA announced this week</a></span> that it is initiating a multi-pronged approach to try to curb the illegal sales of e-cigarettes to underage youths. That includes Juul, a vaping product popular with teens that looks like a flash drive (see this blog Apr. 14, 2018). <br /><br />The FDA's current multi-pronged approach includes; 1) Identifying retailers that are selling e-cigarettes to minors and sending them warning letters, 2) working with e-bay to remove listings for Juul on its website, and 3) working to hold manufacturers of Juul and other e-cigarettes accountable for how their products are marketed and used. <br /><br />Publicly, at least, Juul claims it is opposed to the use of its products by minors. But that claim is hard to square with Jull's youth-friendly product design and the kinds of flavors that the nicotine-containing "pods" come in. <br /><br />It will be hard to curtail what many people might see as a relatively minor crime. We'll see how far the FDA gets with this. <br /> Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-34943967328609427232018-04-25T13:22:00.000-04:002018-04-25T13:22:09.495-04:00First FDA-Approved Drug Derived from MarijuanaAn FDA advisory committee has <span style="color: blue;"><a href="https://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/Drugs/PeripheralandCentralNervousSystemDrugsAdvisoryCommittee/UCM604730.pdf" target="_blank">recommended the approval</a></span> of a new drug, called Epidiolex, for the treatment of several types of epilepsy in children . If the FDA accepts the recommendation, Epidiolex will be the first FDA-approved drug to contain cannabidiol (CBD), a non-psychoactive substance purified from marijuana (cannabis). <br /><br />Following the discovery that CBD had certain medical benefits, a number of states (30 at last count) legalized marijuana for certain medical purposes. Several other states legalized just the CDB extract. Relatively pure CBD is now widely sold over the internet for a host of medical and quasi-medical conditions, including as a sleep aid, an anti-anxiety treatment, an anxiety reliever, and even as a cure for certain types of cancer. But while some of these alleged benefits of CBD may be true, none has been proven by rigorous scientific studies. In addition, the purity and consistency of non-FDA-approved drugs sold over the internet can be suspect. <br /><br />What makes Epidiolex different is that its developer and manufacturer has gone through the necessary testing to prove its medical efficacy. As a result, Epidiolex is poised to receive FDA approval for the treatment of two rare types of epileptic seizures. A distinct advantage of FDA approval is that patients with the forms of epilepsy targeted by the drug can be assured of the drug's purity and consistency of dose from one prescription to the next, because the drug will be produced according to best pharmaceutical practices. <br /><br />With further testing, the FDA could expand the approved use of CBD to include other medical conditions. In the meantime (even if the FDA does eventually approve CBD, or even marijuana, for other uses), I doubt that marijuana-users will give up their favorite form of self-medication. <br /> Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-53221376791764640552018-04-14T11:35:00.000-04:002018-04-14T11:35:03.452-04:00Juul Vaping Product Appeals to MinorsThe latest fad among teenagers: Juul, a nicotine-containing vaping product that looks like a flash drive. Teachers report that some students take them to school and have been caught smoking them in class. <br />
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Juul cannnot be sold legally to persons under the age of 21. Juul is intended for adults who want curb their smoking habit, according to <span style="color: blue;"><a href="http://juulvapor.com/">Juulvapor.com</a></span>. But if that's so, why did they design the device to look like a flash drive? One has to believe that there is a reason for their strange design choice. And why sell nicotine-containing "Juulpods" in flavors that appeal to kids, such as mango and fruit medley? <br />
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Aftermarket sellers of Jull-compatible pods containing nicotine were quick to see the kids potential in Juul; they now sell pods in flavors such as strawberry, blueberry, and watermelon. Does anyone really believe that this product was designed solely for adults?Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-54492057608361761422018-04-10T09:25:00.000-04:002018-04-10T09:25:24.942-04:00Non-Antibiotic Drugs May Contribute to Antibiotic ResistanceWe've discussed on this site a number of times the role that antibiotics play in the development of antibiotic resistance. But it turns out that that's just the half of it; <span style="color: blue;"><a href="https://www.nature.com/articles/nature25979" target="_blank">new research</a></span> shows that some non-antibiotic drugs, including painkillers, antipsychotics, and drugs to combat high blood pressure, can also contribute to antibiotic resistance. <br /><br />These findings are going to make efforts to combat antibiotic resistance harder than previously thought. Many drugs, such as those to combat high blood pressure, are meant to be taken for the rest of the patient's life; one can't just stop taking them because they may affect the bacteria in your gut. What to do? <br /><br />If there is any good news in this latest research, it is that the tests revealed that a few drugs used to treat other diseases actually turned out to have some antibiotic activity as well, according to <span style="color: blue;"><a href="https://www.economist.com/news/science-and-technology/21738985-they-may-also-though-be-source-new-antibiotics-non-antibiotic-drugs-promote" target="_blank">an article in the popular press</a></span> on the subject. Perhaps some of these drugs could be tested further and then used to combat the increasing number of antibiotic resistant bacteria. But it's a long shot.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-2117679229284330482018-04-05T18:43:00.000-04:002018-04-05T18:43:15.806-04:00A Cancer Warning on Coffee?Responding to a lawsuit from a non-profit toxic chemicals watchdog group, a superior court judge in California has issued a <span style="color: blue;"><a href="http://cdn.cnn.com/cnn/2018/images/03/29/coffee.proposed.stmt.of.decision.after.trial.pdf" target="_blank">preliminary judgment</a></span> that may ultimately require coffee roasters and sellers to post warnings that coffee may pose a cancer risk. How did it come to this? <br /><br />Well, it turns out that during the coffee roasting process, a miniscule amount of a chemical called acrylamide is created. Acrylamide is on California's list of cancer-causing or toxic chemicals. And back in 1986, California voters passed Proposition 65, a law requiring businesses and sellers to inform consumers about any possible exposure to toxic or cancer-causing agents in their products. An exception to this requirement can be granted only if the seller can prove that the exposure (in this case, to coffee) poses "no significant risk". But how would Starbucks, for example, ever be able to prove a negative (a complete lack of risk, over a lifetime)? Do you think Starbucks is up to that task? <br /><br />It's true that there's acrylamide in coffee, but the levels are orders of magnitude below levels that have ever been shown to be a risk factor for cancer. So is the judge's ruling an example of regulatory overreach? Is Proposition 65 functioning as intended? Where do we draw the line between protecting the public and scaring them needlessly? For more on this controversy, read <span style="color: blue;"><a href="https://www.npr.org/sections/thetwo-way/2018/03/30/598348764/fact-check-calif-judge-rules-coffee-must-come-with-a-cancer-warning-but-should-it" target="_blank">an article</a></span> by NPR here. <br /><br />What do you think?<br /> Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-80075997248761259762018-03-29T09:04:00.000-04:002018-03-29T09:04:06.300-04:00Fitness and DementiaMore than 5 million people in the U.S. are living with Alzheimer's disease, the most common form of dementia. There is no cure or prevention for Alzheimer's disease, despite all the research into its causes. <br /><br />Now a <span style="color: blue;"><a href="http://n.neurology.org/content/early/2018/03/14/WNL.0000000000005290" target="_blank">new study</a></span> spanning 46 years offers some tantalizing clues. Way back in 1968, researchers in Sweden enrolled 191 women 38-60 years old into a study of cardiovascular fitness, as measured by their capacity to exercise on a bicycle until they became so fatigued that they had to stop. Based on their workload achieved, they separated the women into "low", "medium" and "high" fitness groups. Then they followed the women for the next 44 years, looking for signs of dementia, among other health issues. Surprisingly, they found that compared to the "medium" fitness group, those in the "high" fitness group were 88% less likely to develop dementia. Among those who did develop dementia, high fitness delayed the time to onset of dementia by 5 years, compared to the medium fitness group. <br /><br />A word of caution; these results show a correlation only; they do not prove that high fitness <i>per se</i> is what is reducing the risk of dementia. Perhaps the high fitness group also has a better diet, or just better genetics to begin with. Nevertheless, the results are intriguing, and may point the way to additional research to tease out the actual cause. Anything we can do to solve this baffling and debilitating disease would be welcome. <br /> Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-68085670471165302582018-03-25T21:53:00.000-04:002018-03-25T21:53:34.282-04:00The Origin of Sickle Cell TraitTens of millions of people have a genetic mutation in a single allele (one of a pair of genes) that by itself has no outward effect on the person's health, called sickle cell trait. Unfortunately, persons who inherit two copies of the allele (one from each parent) suffers from sickle cell disease, a debilitating condition in which red blood cells cab change shape, or sickle, impeding blood flow and damaging organs. <br /><br />Typically, a genetic mutation that leads to health problems would be selected against over time by normal evolutionary processes. However, that's not the case for sickle cell trait, because it turns out that inheriting just one copy of the abnormal gene is protective against another disease, malaria. As a result the abnormal gene is selected for, not against, by evolutionary processes, especially in places such as Africa where malaria is common. <br /><br />But where and when did the mutation arise? The genetic mutation comes in five different haplotypes, or forms, leading some scientists to speculate that the mutation arose independently perhaps as many as five different times. Others have suggested that it arose just once. <br /><br />In attempt to <span style="color: blue;"><a href="http://www.cell.com/ajhg/fulltext/S0002-9297(18)30048-X" target="_blank">resolve the dispute</a></span>, researchers recently studied the genomes of nearly 3,000 people. 156 of them had the mutated gene for sickle cell trait. On close examination of their genomes (the details are beyond the scope of this blog), the researchers concluded that all 156 people had inherited the mutated allele from a single person who lived around 7,300 years ago. That person probably lived in western or central Africa. Case closed, it seems.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-32278668540515458872018-03-22T09:00:00.000-04:002018-03-22T09:00:26.211-04:00Rates of STD Infection in the U.S. Continue to RiseThe rates of infection of most STDs rose again in 2016, <span style="color: blue;"><a href="https://www.cdc.gov/std/stats16/natoverview.htm" target="_blank">according to the CDC</a></span>. Compared to 2015, chlamydia infections were up 4.7%, syphilis infections increased 17.6%, and gonorrhea was up by 18.5%. The increases are part of a trend that started about a decade or so ago. <br /><br />The only good news is that <span style="color: blue;"><a href="https://www.cdc.gov/hiv/pdf/library/reports/surveillance/cdc-hiv-surveillance-report-2016-vol-28.pdf#page=110" target="_blank">rates of HIV infection</a></span> have been trending slightly downward over the past five years. Compared to 2015, the rate of HIV infection declined by 0.1% in 2016. <br /><br />The dramatic increases in syphilis and gonorrhea infections in 2016 are cause for concern, of course. Sexually active individuals should be aware of these trends and seek to protect themselves accordingly.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-88853302794132837002018-03-21T10:13:00.001-04:002018-03-21T10:13:42.696-04:00Exercise Can Turn Back Time on a Middle-Aged HeartSo... you didn't take care of your body when you were young, and now at middle age you're feeling out of shape and over the hill. You're motivated to make a lifestyle change if it would help, but will it actually do any good at this point? <br /><br />The good news is that perhaps it will. According to <span style="color: blue;"><a href="http://circ.ahajournals.org/content/early/2018/01/03/CIRCULATIONAHA.117.030617" target="_blank">a report in <i>Circulation</i></a></span>, just two years of high-intensity exercise improves heart health. In the study, sedentary middle-aged men (mean age 53 years) participated in either a moderate to high intensity aerobic exercise program for two years (the experimental group), or only non-aerobic exercise such as yoga or balance training (the control group). At the end of two years, those who had exercised showed signs of improved heart health, including improved oxygen uptake and a reduced stiffness of the left ventricle. It's as if the clock was turned back on the heart aging process. <br /><br />Middle age may be the last time that one can improve heart function, however. According to <span style="color: blue;"><a href="https://www.npr.org/sections/health-shots/2018/03/12/591513777/hearts-get-younger-even-at-middle-age-with-exercise" target="_blank">an NPR article</a></span>, the same improvement is not possible by the time one reaches seventy years of age. The time to get moving is now, not later.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-72974349563124508522018-03-20T20:28:00.002-04:002018-03-20T20:28:53.553-04:00Herbicides Can Alter the Nutritional Content of Food CropsHerbicides are widely used commercially to improve crop yields and to reduce the need for hoeing and weeding. But do herbicides affect the nutritional content of food crops? Are organic foods nutritionally different from non-organic foods, and if so, are they better for you? Surprisingly, very little research has been done on this subject. <br /><br />A <span style="color: blue;"><a href="https://pubs.acs.org/doi/10.1021/acs.jafc.7b05885" target="_blank">research paper</a></span> published last month in the <i>Journal of Agricultural and Food Chemistry</i> suggests that some common herbicides can indeed change the nutritional content of a food crop (sweet corn). The research team exposed sweet corn to four different herbicides, with or without a commonly used "safener", which helps to protect the corn from herbicide damage. All of the herbicides increased the protein content of the corn slightly, and some of them increased the content of certain minerals (phosphorus, magnesium, manganese, and iron) as well. Several of the herbicides also altered the balance of sugars (fructose/glucose/sucrose) and the amounts of fatty acids. <br /><br />Whether the effects of herbicides on nutritional content are good or bad is still an open question. All that can be said at the moment is that herbicides can affect the nutritional content of food plants in a myriad of ways. <br /><br />A lot is still unknown about the effects of agricultural chemicals on food crops, including whether herbicides affect the food's taste. Further research is warranted.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-15141622645943994242018-03-09T19:30:00.000-05:002018-03-09T19:30:35.330-05:00Australia May Become the First Country to Eradicate Cervical CancerIf the current trend continues, Australia may become the <span style="color: blue;"><a href="http://www.iflscience.com/health-and-medicine/australia-is-on-track-to-become-the-worlds-first-country-to-eradicate-cervical-cancer/" target="_blank">first country to virtually eradicate the HPV virus</a></span> that causes cervical cancer. How did they do it? Health officials credit an aggressive government-financed vaccination campaign begun in 2007 that targeted 12-13 yr.-old girls, combined with a catch-up program to vaccinate older girls and women up to the age of 26 that was completed in 2009. By 2015, 53% of women in the now 18-35-yr.-old age group had been vaccinated. More importantly, rates of HPV infection have <span style="color: blue;"><a href="https://academic.oup.com/jid/advance-article-abstract/doi/10.1093/infdis/jiy075/4841780?redirectedFrom=fulltext" target="_blank">dropped from 22.7% to less than 1.5%.</a></span> That's a 93% decline in HPV infection rates!<br />
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Why did HPV infection rates drop so dramatically when only 53% of the women have been vaccinated so far? It's the well-known "herd effect" - when enough people in a population are immune to a transmissible disease organism, it's much harder for the organism to be transmitted from person to person, even though some people are not yet immunized. <br />
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Although health officials have not yet seen a dramatic decrease in the number of cases of cervical cancer, that's because it can take years for cervical cancer to develop after HPV infection. At the moment, the number of cases of cervical cancer is just beginning to decline. Nevertheless, officials are confident that with continued aggressive vaccination against HPV, within 30-40 years cervical cancer will be a thing of the past in Australia. <br />
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The full HPV vaccination regimen costs about $400 per person in the U.S.; probably less in a country like Australia with a government-sponsored program. Sounds like a pretty good deal to me.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-40245668454472123922018-03-08T11:09:00.001-05:002018-03-08T11:09:44.893-05:00A New Risk Factor for Heart Attack and StrokeWhy is it that most patients who have had a stroke or a heart attack don't have any of the normal risk factors, such as high cholesterol or high blood pressure, that are generally associated with cardiovascular risk? The answer, it seems, may be a risk factor that has been missed until now; a condition called <span style="color: blue;"><a href="https://www.todayonline.com/world/bone-deep-heart-threat-emerges" target="_blank">clonal hematopoiesis of indeterminate potential</a></span>, or CHIP. <br /><br />In essence, CHIP is a condition in which some of the stem cells in bone marrow that initiate the production of white blood cells (WBCs) begin to mutate, resulting in the increased production of white blood cells carrying the mutation. Patients with an increased number of these mutated WBCs in their blood are 40-50% more likely to die of a stroke or a heart attack within 10 years. Apparently, the risk of developing CHIP goes up sharply with age. Although only about 20% of 60-yr-olds have developed CHIP, half of all 80-yr-olds have the condition. It's almost as if CHIP is a normal consequence of aging. <br /><br />And how might CHIP contribute to cardiovascular disease risk? Researchers have long speculated that chronic inflammation may contribute to the development of blood vessel-blocking atherosclerosis. And its possible that chronic inflammation is initiated by increased numbers of inflammatory WBCs in the blood.<br /><br />Doctors are not advising their patients to be tested for CHIP yet, because at the moment there is nothing to be done about it even if you do test positive. At least not yet; perhaps some day there will be.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-42289094745177446372018-02-27T08:23:00.003-05:002018-02-27T08:23:54.792-05:00New Hope for Children With Severe Peanut AllergiesEvidence is beginning to accumulate that severe peanut allergies can be made less severe over time by careful, regulated exposure to small doses of peanut flour. In <span style="color: blue;"><a href="http://ir.aimmune.com/news-releases/news-release-details/aimmune-therapeutics-pivotal-phase-3-palisade-trial-ar101-meets" target="_blank">a recent study</a></span>, over 500 children aged 4 to 17 with severe peanut allergies were exposed either to small amounts of peanut flour delivered in their food for six months, or to a non-peanut flour. By the end of the study, 67% of those exposed to the peanut flour were able to tolerate the equivalent of several peanuts, compared to only 4% of those receiving the dummy flour. While children who have had severe peanut allergies probably wouldn't ever be able to eat peanuts with reckless abandon, the treatment should be enough to keep them safe if/when they are inadvertently exposed to tiny amounts of peanut allergen in their environment. <br /><br />The study has not yet been peer-reviewed. And it's worth noting that 12% of the study's participants dropped out before completion of the study because of "adverse events" (reactions to the treatment). In other words, the treatment may not work for everyone. <br /><br />When commercialized, a full course of treatment is expected to cost $5,000 to $10,000. That's a lot to pay for peanut powder, but presumably the real cost is in quality control and patient monitoring. For the patient with life-threatening peanut allergies, the treatment might be priceless. <br /> Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-6969182794006371362018-02-23T14:20:00.003-05:002018-02-23T14:20:53.861-05:00A Blood Test for Concussions Traditionally, people who are suspected of having a concussion are first evaluated by a series of neurological tests known as the Glasgow Coma Scale. If the results of the Glasgow test warrant it, a computed tomography (CT) scan is conducted to try to detect intracranial lesions requiring treatment. Problem is, most CT scans are negative for lesions, meaning that a lot of CT scans are done unnecessarily. <br /><br />Now, however, there's <span style="color: blue;"><a href="https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm596531.htm" target="_blank">a blood test for concussions</a></span>. The test measures the levels of certain proteins that are released into the blood by damaged brain tissue in the first 12 hours after a concussion. The test is highly accurate; it correctly identifies a concussion 97.5% of the time in patients also identified by a CT scan, and correctly identifies a person as <i>not</i> having a concussion 99.6% of the time when a CT scan is also negative. Aside from being less expensive, the blood test could be done in the field (perhaps even on the sidelines of a sporting event), allowing better decisions about who does and doesn't need a CT scan. <br /><br />The blood test is currently approved only for use on adults, but the company that makes the testing device is working toward getting it approved for children as well. That would make it available for the more than a million boys who play high school football each year, as well as athletes in other contact sports.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-89390806634403522442018-02-18T14:36:00.000-05:002018-02-18T14:36:07.973-05:00Keeping Human Organs Alive Longer Before TransplantationOne of the practical limitations to transplantation of organs from a recently-deceased donor to a recipient is the length of time that human organs remain viable outside a human body. Even if the organ is immediately cooled on ice, it's only a matter of hours before it is no longer considered healthy enough for transplantation. Sometimes it would take too long to transport the organ from where it is harvested to where it is needed, even if pilots and planes were standing by to transport it. <br /><br />That may be about to change. Several companies (<span style="color: blue;"><a href="http://www.organox.com/" target="_blank">OrganOx</a></span> and <span style="color: blue;"><a href="http://www.transmedics.com/wt/page/how_works.html" target="_blank">Transmedics</a></span>) are working to extend the time during which human organs can be kept alive outside the body for up to a full day. This is being accomplished not by cooling the organ, but by keeping it warm and perfused with blood throughout storage and transport so that the organ's metabolic requirements are met and it can continue to function. The techniques require some expensive equipment (much more expensive than just a cooler of ice!), but if lives can be saved the extra cost may just be worth it. <br /><br />And if we are allowed to dream, if the time of organ storage outside a human body could be extended to weeks or even months, it might be possible to establish human organ banks in some distant future!Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0tag:blogger.com,1999:blog-2839395069077649743.post-51354010775490591312018-02-08T08:43:00.000-05:002018-02-08T08:43:55.099-05:00New Treatment for a Penile Dysfunction ConditionPeyronie's disease - the disease we never knew existed until there was a cure for it. TV commercials about the condition ask cryptically "Are you curved below the belt?". It took me a minute to figure that one out! In fact, Peyronie's disease is a relatively rare condition in which scar tissue in the penis causes marked curvature of the penis during an erection, leading to painful erections and problems having sex. What causes the scar tissue to develop is generally unknown, although prior physical injury is suspected in many cases.<br /><br />In December the FDA approved the first non-surgical treatment for Peyronies's disease after reviewing the <span style="color: blue;"><a href="https://www.sciencedirect.com/science/article/pii/S0022534713002279" target="_blank">results of two studies</a></span>. Shortly thereafter the company producing the treatment, Endo Pharmaceuticals, launched an aggressive disease awareness and product marketing campaign. And why not? There's a lot of money to be made. Treatment will cost $26,000 in addition to the doctor's fees. Treatment involves 8 injections into the penis six weeks apart of Xiaflex, a collagenase derived from the bacterium that causes gangrene.<br /><br /><span style="color: blue;"><a href="https://peyronies-disease.xiaflex.com/patient/about/" target="_blank">Endo Pharmaceuticals says</a></span> that "3-9% of adult males worldwide are estimated to have Peyronie's disease", but no evidence is presented to back that up. Estimated by whom? Sigh. For now we'll just have to put up with those annoying ads.Michael Johnsonhttp://www.blogger.com/profile/08716482790912907481noreply@blogger.com0