Sunday, March 1, 2015

Screening Newborns for Genetic Disorders

Back in 2000, most U.S. states screened newborn infants for just four genetic disorders. Today 42 states screen for at least 29 of the 31 genetic or metabolic disorders for which an Advisory Committee of the Department of Health and Human Services recommends newborns be screened. The list includes cystic fibrosis, sickle cell anemia, hypothyroidism, phenylketonuria, and a host of other conditions so rare you’ve probably never heard of them.

A link to your state's screening programs and tests can be found on the website of the National Newborn Screening and Global Resource Center.

Wednesday, February 25, 2015

Superbug deaths in Los Angeles

According to news reports, including one by CNN, a CRE "superbug" killed two patients and infected five more in Los Angeles. All seven were in an L.A. the hospital for an endoscopic procedure to diagnose problems with their bile duct, gall bladder or pancreas. An investigation revealed that all seven patients had been scoped with one of two endoscopes, which (apparently) weren't sterilized effectively even though sterilization protocols were followed. The sterilization procedure will have to be revised, obviously.

CRE stands for Carbapenem-Resistant Enterobacteriaceae, a family of bacteria that includes E. coli and Klebsiella pneumoniae. Carbapenem is an antibiotic of last resort when most other antibiotics no longer work, and Klebsiella seems to have found a way to neutralize it. So far, Klebsiella is found only in hospitals, where equipment or personnel can harbor these hard-to-transmit bugs; the wider community is not yet at significant risk. But the big danger is that Klebsiella will pass their antibiotic-neutralizing skill on to other bacteria (see this blog, Apr. 7, 2011), leading to much wider outbreaks than we've seen so far.

This little outbreak is not likely to be the last.

Sunday, February 22, 2015

Britain Allows Three-Parent IVF Procedures

Once again, Britain takes the lead in unusual IVF procedures. You may recall that the first "test tube baby" was conceived and born in Britain; now the union of egg and sperm in a test tube is commonplace. This time, Britain becomes the first nation to allow the creation of children with not two, but three biological parents.

The decision opens the way to solve a rare but vexing problem; what to do when a genetic disease is caused not by a defective allele in the father's or the mother's nuclear DNA, but in the small amount of DNA in mitochondria. As you may know, mitochondrial DNA is inherited from the mother, and only the mother. Mitochondrial genetic diseases, therefore are always passed from a mother to all of her daughters. There's no genetic mixing, and hence no possibility of avoiding that outcome. To break this pattern requires replacement of the mother's mitochondrial DNA entirely prior to fertilization.

What Britain approved, then, is an IVF procedure in which the nucleus is removed from a donor woman's egg and replaced with the nucleus from the birth mother's egg. That "two-mother" egg is then fertilized with the father's DNA. The child will have nuclear DNA that is half from the mother and half from the father, but mitochondrial DNA that is all from donor. And here's the good news; the mitochondrial defect carried by the child's birth mother is forever removed from all of her descendants, forever.

Yes, it smacks of "playing God", if that's what you wish to call some of the most advanced techniques in medicine. But it's hard to argue against it when the benefits are so clear.

Thursday, February 19, 2015

Childhood Vaccinations and the Religious Objection

What exactly is the "religious objection" to vaccinating children, and why are so many parents objecting for religious reasons? According to a New York Times article, the recent outbreak of measles is causing some states to take a hard look at that question. And one obvious answer is that allowing exemptions to childhood vaccination requirements for medical or religious reasons but not for personal beliefs leaves the door wide open for personal beliefs to become (conveniently) religious objections. After all, how can you disprove a religious objection? In truth, though, except for Christian Scientists there is virtually no valid canonical basis for a religious exemption to vaccinations in any of the world's major religions.

In a recent review of more than 60 reports of vaccine-preventable infectious disease outbreaks that started in religious communities, the author found that in many cases, "ostensibly religious reasons to decline immunization actually reflected concerns about vaccine safety or personal beliefs among a social network of people organized around a faith community." In other words, the religious exemption is being used by parents because it's what's available, not because it's especially valid.

It'll be interesting to see how state's childhood vaccination laws evolve regarding which exemptions are allowed and which are not.

Monday, February 16, 2015

Sea-Level Rate of Rise is Increasing

The sea level is rising more quickly now than in the past, according to new estimates. Using probabilistic techniques and data re-analysis, a recent study estimates that between 1901 and 1990 the sea level rose by an average of 1.2 mm/year. But between 1993 and 2010, the sea level rose at an annual rate of 3 mm/year; two and a half times as fast as in the past.

Two factors are probably contributing to the increased rate of rise. One is a steady decline in arctic and glacial ice, and the other is an increase in ocean temperatures; water expands as it warms. I'm sure there will be arguments about WHY the glaciers and sea ice are melting and the oceans warming, but it would be hard to deny that the sea level is rising more quickly than in the past.

Monday, February 9, 2015

California’s Childhood Vaccination Law

California law “requires that children be up-to-date on their immunizations (shots) to attend school or child care”, according to the California Department of Health Services. The law allows for exemptions because of a medical condition, but it also allows for an exemption based on “personal beliefs” which are not specified. The exemption certificate requires a doctor’s signature, but it’s not for the purpose of identifying a medical exemption; it’s to certify that the doctor has counselled the parents about the risks and benefits of vaccination and the risks of communicable diseases. The requirement for the doctor’s signature gets the doctor and the state off the hook if anything bad happens to the child as a consequence of not being vaccinated. Parents can choose to ignore the doctor’s advice, and they’ll still get the exemption.

In other words, California has a “mandatory requirement” that children be vaccinated to attend school, except that in practical terms it really doesn’t. Other states have similar laws. It seems that the politicians who write these laws are trying to satisfy everybody, with the result that the laws just don't work for the majority of people who favor vaccinations.

Parents of unvaccinated children often say, “What does it matter to you if my child isn’t vaccinated?” Well, there are always some children who can’t be vaccinated for medical reasons, even if they wanted to be vaccinated. An example is childhood leukemia; the chemotherapy for leukemia leaves a child vulnerable to infection but unable to be vaccinated effectively. Children with leukemia are put at risk when other children who could be vaccinated choose not to be vaccinated. And of course all children under the age of 1, who are too young to be vaccinated yet, are put at risk too.

What will it take to open people’s eyes to the fact that vaccinations are a good thing? I hope it doesn’t take the return of a truly debilitating disease such as polio. But it may.

Thursday, February 5, 2015

"Low T" Versus Hypogonadism

A while ago (this blog June 26, 2013) I reported on the increasing trend for men, many of them young, to use testosterone products like Androgel and Axiron to boost their testosterone levels. They're being encouraged by the sellers of such products to correct what the sellers call "low T". Here are some facts to consider:

Testosterone replacement therapy is only approved by the Food and Drug Administration (FDA) for the treatment of hypogonadotropism, a clinical condition characterized by measurements of blood levels of testosterone of less than 300 ng/dl and one or more clinical symptoms of androgen deficiency. Hypogonadism is not that common in young men; a study in the Journal of Clinical Endocrinology and Metabolism found that only about 5.6% of men under 70 had hypogonadism.

And yet, sales of prescription testosterone-containing gels, creams, and liquids that are absorbed through the skin totaled more than $2 billion in 2012 alone, according to an article in the New York Times. The companies who make these types of products claim with a perfectly straight face that their advertising campaigns are only aimed at educating men who may be at risk of having hypogonadism, so that they can talk to their doctor. They say that they don't condone the use of testosterone products for purposes other than those approved by the FDA, but whom are they kidding? There aren't enough men with hypogonadism in the world to support those kinds of sales numbers.

Don't buy the hype. If you're a normal young man you don't need more testosterone unless you have been properly examined and tested by a physician. Enough is plenty. And these products do have some unwanted side effects you should know about. Do your homework.