Monday, April 26, 2010

Paying Living Donors for a Kidney

Arguments against paying living donors for a kidney generally focus on two ethical concerns; 1) that payments might induce a potential donor to ignore the risks associated with kidney donation, and 2) that payments might exploit poor people, who would have a greater incentive to donate than wealthier persons.

To test these concerns, a team of researchers polled 342 potential donors in Philadelphia. The study found that potential donors’ perception of the risk of kidney donation is completely unaltered by how much money is offered for their kidney ($0, $10,000, or $100,000). The study also found that although a potential donor’s willingness to donate is influenced by money (more money, more willingness to donate), the effect of money was the same across all income strata. In other words, there was no evidence that payments would either induce donors to ignore risk or specifically exploit poor people.

Based on these data, perhaps payments should be offered to donors on a trial basis. It’s worth knowing whether potential donors’ actual choices would be the same as their hypothetical choices on a survey.

Saturday, April 17, 2010

Medical Spas Warned about Lipodissolve

Medical spas are making big bucks on a procedure called lipodissolve, the latest fad for getting rid of unwanted fat. The procedure involves the injection directly into subcutaneous fat deposits of two active ingredients that allegedly break the bonds in the molecular form of stored fat. The active ingredients may also disrupt the cell membranes of fat cells, causing death of the cells. Goodby, fat! But does it work?

In fact, the products used in the lipodissolve procedure have never been evaluated and approved for that purpose by the U.S. Food and Drug Administration (FDA). The safety and efficacy of the lipodissolve procedure is unknown. So this month the FDA sent warning letters to six U.S. medical spas and to a Brazilian firm that advertises the lipodissolve procedure over the internet, warning them to stop making false or misleading statements about the products used in the procedure. The letters warned that assertions that the products used in lipodissolve are safe and effective, have an outstanding safety record, or are superior to other fat-loss procedures are unwarranted and are in violation of the federal FDA Cosmetic act. The companies must take action to correct the violations and to prevent future ones or they will face legal action.

Friday, April 16, 2010

Inflammation and Type 2 Diabetes

Scientists have long suspected that inflammatory processes play a role in certain chronic diseases, such as Type 2 diabetes and atherosclerosis, and now there’s preliminary evidence. In a clinical trial involving 104 patients, an anti-inflammatory drug related to aspirin called salsalate lowered blood levels of hemoglobin A1c levels and triglycerides slightly in Type 2 diabetics. (Hemoglobin A1c levels are the “gold standard” for monitoring long-term effectiveness of glucose control in diabetic patients.)

Scientists caution that no one should start taking salsalate just yet to try to prevent or treat diabetes or atherosclerosis. Larger clinical studies involving many more patients will be needed before salsalate is becomes a standard treatment for these diseases. Nevertheless, these preliminary findings bring us just a little bit closer to an understanding of the link between obesity and inflammation, and whether (and if so, how) inflammation contributes to chronic diseases such as Type 2 diabetes.

Friday, April 9, 2010

Antibiotic-resistant Gram-Negative Bacteria

You’ve probably never even heard of Acinetobacter baumannii or Enterobacter aerogenes. But these and other little-known gram-negative bacteria are killing tens of thousands of hospitalized patients every year, according to some estimates.

Gram-negative bacteria (so-called because of the way they are stained during the Gram staining protocol) have a cell wall structure that makes them more difficult to kill with antibiotics in the first place. But some strains of these bacteria are now resistant to every modern antibiotic we have.

In an ironic twist, two antibiotics (colistin and polymyxin B) that are somewhat effective against these resistant bacteria are still effective only because they were essentially abandoned decades ago, when it was learned that they can cause nerve and kidney damage. Now it’s become an unpleasant trade-off at times; risk death from the bacteria, or risk possible nerve and kidney damage from the antibiotics.

New antibiotics are needed, but so far there do not appear to be any “magic bullet”-type antibiotics on the horizon. This is a battle we’re slowly losing.

Monday, April 5, 2010

Human Gene Patents Invalidated

Basing his decision on legal arguments that human genes are products of nature and hence cannot be patented, in March of 2010 a U.S. District Court judge invalidated several patents held by a company called Myriad Genetics on the human breast cancer genes, BRCA1 and BRCA2. Myriad Genetics sells a kit used to test for the two genes for about $3,000. The company tried to argue that their method of isolating the genes changed the genes, and thus made them patentable. But the judge ruled that such an argument was just a trick to circumvent the prohibition on the direct patenting of DNA.

About 20% of human genes have already been patented. A number of biotech companies were planning to make a hefty profit by developing and selling patent-protected genetic tests or by selling the patent rights to others. Whether all of those patents could ultimately be invalidated is unclear. With potentially billions of dollars at stake, the decision is likely to be appealed.

Medical and research organizations and patients are pleased by the decision. If it holds up on appeal it should provide wider access to human genes currently under patent protection, and ultimately make genetic tests like those for BRCA1 and BRCA2 less expensive.

Thursday, April 1, 2010

DNA Mutations Between Generations

How often do errors in DNA replication occur between generations – i.e., how many times are new mutations found in a child that were not present in a parent? These new mutations created between generations would represent a “human mutation rate”. Undoubtedly they would contribute to human evolutionary change.

The human mutation rate per generation has been difficult to measure, but several different laboratories have now come up with numbers that are remarkably similar. According to the most recent estimate, the answer is about 60 DNA nucleotide base errors per generation. That sounds like a lot, but given that there are 3 billion nucleotide base pairs (6 billion bases) in the DNA in a human cell, that’s just one error in every 100 million bases. DNA replication and repair mechanisms are remarkably accurate, it seems.

And that’s why human evolution has occurred so slowly, over several million years.