Monday, March 28, 2016

The Rate of Climate Change Could Accelerate

A respected group of climate scientists has concluded that climate change and its negative effects are likely to occur much more rapidly than previously thought. The authors predict that within just 50-150 years Earth will experience massive storms, the disappearance of large portions of the polar ice sheets, and a rise in ocean levels of several meters; enough to inundate some coastal cities. According to the authors, we are already in the early phase of an accelerated period of temperature rise similar to one that occurred naturally about 120,000 years ago. By the time that one was over, ocean levels had risen by a whopping 20-30 feet.

What is new about this prediction is the rapidity of the changes; the authors conclude that they could occur in just a couple of human generations, and not over thousands of years.

While not all scientists are absolutely convinced by this paper, it appears that they are taking it seriously. It is likely that this paper will cause other scientists to examine the data to see if it fits with their own predictive models. Little by little, through the scientific process of testing and retesting, we come closer and closer to the truth. We cannot afford to get this one wrong.

Sunday, March 27, 2016

Using "Incompatible" Kidneys for Transplant

Every year, hundreds of patients who need a new kidney die before a donated kidney (either from a living person or a cadaver) can be found for them. The basic problem is that the donated kidney has to be a good immunological match for the recipient (the patient) or his/her immune system will attack the donated kidney, ultimately causing it to be rejected. But before we blame the immune system for this problem, remember that the immune system protects us from infectious diseases precisely because it attacks foreign tissues and cells, such as bacteria.

Knowing how the immune system works, scientists think they may have found a way to circumvent the system so that any kidney could be used in any recipient. It would mean that a husband could donate to his wife, for example, or any friend could donate to a friend in need. This would be a huge advance, because the chance of a good immunological match between two unrelated individuals is around one in 100,000 or more.

In the procedure, called "desensitization", the patient's antibodies are filtered out of the blood. (They're replaced by an infusion of other antibodies to provide some temporary protection from infection.) After the kidney transplant, the patient's immune system slowly replenishes the patient's own antibodies, but for some reason these new antibodies are not as likely to attack the foreign (donated) kidney.

  According to a recent summary study, the 8-year survival rate of desensitized patients who received an incompatible kidney was 76%. That compares favorably to the 44% survival rate of a matched group of control patients who simply remained on the transplant list.

Friday, March 25, 2016

Zika Virus Infections and Fetal Damage

We're learning more about the effect of a Zika virus infection on an unborn fetus every week. Two new reports strengthen the link between Zika virus infection during pregnancy and an increased risk of birth defects, most notably microcephaly. One ongoing study is following pregnant women in Brazil who were infected with the Zika virus during pregnancy. Forty-two of the women agreed to have regular ultrasounds to study the progression of the fetus. Among those 42 women, the fetus has already died or appears to suffer from serious birth defects in 12 of the women. Only 8 of the women have given birth so far, and in all cases the ultrasound diagnoses were accurate. The study will continue until all of the women have given birth, but the preliminary results are pretty dismal; a 29% rate of fetal death or significant fetal problems.

In a second laboratory-based study, researchers showed that the Zika virus appears to attack and kill human neural progenitor cells that will ultimately form the cortex of the brain. In this study, the researchers cultured various fetal cells and then exposed them to the Zika virus. The cultured neural progenitor cells were infected and killed by the virus, whereas several other types of cultured fetal cells were not.

There is no vaccine yet for the Zika virus. Although research into Zika vaccines is underway, it is likely to be several years before one is available. And because this is the first major outbreak of the virus, there are almost no women who are currently immune to the virus by virtue of a previous exposure. The clock is ticking.

Tuesday, March 15, 2016

More Support for Early Exposure to Food Allergens

The hypothesis that early exposure to certain food allergens may reduce the likelihood of children developing food allergies later in life received support recently from two additional studies. The first study, by the same authors that carried out the study described last year (see this blog Mar. 9, 2015) shows that the protective effect of being exposed to peanuts at an early age seems to last a long time, even when peanuts are not consumed at all for a full year. The second study extended these findings by showing that the protective effect of early exposure to allergens is not restricted to peanuts, but seems to apply to other of the usual food allergens such as eggs and wheat. At the very least, early exposure to these allergens does no harm.

The World Health Organization currently recommends that infants be fed only milk for the first six months. With more studies like these two, that recommendation may have to be changed in the future.

Tuesday, March 8, 2016

Maria Sharapova to be Suspended From Tennis

The latest athlete caught up in a doping scandal is Russian tennis player Maria Sharapova, currently ranked #7 in the world by the World Tennis Association and the highest-paid female athlete for the past eleven years. She earned more than $29 million last year, most of it from endorsements.

Apparently Ms. Sharapova tested positive at the Australian Open tennis tournament for a banned substance called meldronium, also known as mildronate. Meldronium is approved in Russia and the nearby Baltic countries for the treatment of ischemia (an inadequate supply of oxygen to the heart, due to a reduced blood flow). Its main use is for patients with angina or heart failure, but apparently it improves blood flow enough that it also improves athletic performance, or at least that's what athletes think. It was banned last year by the World Anti-Doping Agency (WADA) after a 2015 study showed that 17% of Russian athletes, and just over 2% of athletes worldwide, were using it. It is not available in the U.S or Europe.

Ms. Sharapova claims that she's been using the drug since 2006 for "several health issues I was having in 2006", and then just failed to check the list of banned substances in 2015 when meldronium was added to the list.  Really?  You be the judge.

Ms. Sharapova faces a possible suspension from tennis competition of up to four years. Her sponsors are watching the situation closely; several of them (Nike, Porsche, and Tag Heuer) have already suspended their relationships with her. It would be sad if this is how her distinguished career ends.

Saturday, March 5, 2016

Wasted Cancer Drugs?

According to a New York Times article, a recent study claims that billions of dollars are being wasted every year on expensive cancer drugs because some drug companies package the drugs in just one vial size. The study's analysis is based on the fact that a vial is used only once and then thrown away for safety reasons. If not all of the contents of a vial is used (as is likely with a smaller patient) the rest is wasted. According to the study, if the drug companies would just produce several sizes of vials, this waste (and lost money) could be prevented.

While I understand that some cancer drugs are being wasted, I challenge the study's conclusion that a lot of money could be saved if the drug companies just produced vials in different sizes. The notion that drug companies price their drugs based solely on the cost of producing the drug is just plain false. They price their drugs based primarily on how much profit they think they have to make to recoup the nearly billion dollars they spent on drug development and advertising. The price of producing the drug is minimal compared to that. If you asked a drug company to package a drug in several different vial sizes so all of the drug in a given vial would be fully used, in all likelihood they'd just change their prices so that their overall income from the drug remained nearly the same.

I'm not against having cancer drugs available in different-sized vials (and doses). But it might mean that larger patients would pay more than smaller patients, for the same cancer treatment. Is that fair? Think about it.

Wednesday, March 2, 2016

Texas Abortion Law Challenged

A Texas law that has severely restricted access to legal abortions is being argued in the Supreme Court today. Two provisions of the law are at issue; the first requires that any physician performing an abortion must have admitting privileges at a hospital within 30 miles of the abortion clinic, and the second requires that an abortion clinic have the same facilities, equipment, and staff of ambulatory surgical centers, which are much more expensive to set up and run. At issue is whether the law improves patient safety, or whether the law is just another attempt to put as many roadblocks in front of abortions as possible.

Defenders of the law claim that the law provides better access to emergency care should it be needed, while setting appropriately high standards for the qualifications of the doctors performing abortions and the safety of abortion clinics. Opponents of the law, including most medical groups, say that the new restrictions are simply not justified on the basis of any medical evidence. They argue that abortions are safer than some other procedures, such as colonoscopy and liposuction, which are not required by law to be performed in ambulatory surgical centers. They argue that the new law actually makes abortions less safe because women will be forced to seek riskier alternatives. Indeed, since the law was passed in 2013 more than half of the abortion clinics in Texas have a closed.

Who is right? And what do you think the Supreme Court will decide, if anything? With the recent death of Justice Scalia there are currently only 8 members on the court, so the court may be deadlocked on this one.

A decision is expected by June. One possibility is that the court will turn the case back for more information, effectively delaying the decision for another year. By that time there should be a newly-appointed Supreme Court Justice to replace Justice Scalia.