Saturday, April 30, 2011

Supervised Injection Facilities – A Good Idea, or Not?

A recent study published in The Lancet shows that supervised injection facilities, where drug users have access to medical expertise and injection rooms for their injections, can significantly reduce the death rate from drug overdoses. In Vancouver, Canada, for example, deaths from drug overdoses have fallen by 35% in the area immediately around a supervised injection facility that opened in 2003. In contrast, the death rate declined by only 9% in the rest of the city over the same time period.

So, providing supervised facilities for drug users lowers the death rate from overdoses. But does that make it a good idea? Is it the best way to spend tax dollars on drug-related problems in society, compared to spending those same dollars on education, treatment centers, or punishment? YOU decide. It’ll be your taxes at work.

Reference: Marshall, BDL, et al. Reduction in Overdose Mortality After the Opening of North America's First Medically Supervised Safer Injecting Facility: A Retrospective Population-Based Study. The Lancet 377: 1429-1437, 2011.

Friday, April 22, 2011

When Should Blood Pressure be Lowered?

High blood pressure (hypertension) is a well-known risk factor for cardiovascular disease and the adverse cardiovascular events associated with it, such as stroke, heart attack, congestive heart failure, and even death. High blood pressure should always be treated. But what about “prehypertension”, when blood pressure is between the usual definition of hypertension (systolic/diastolic >140/90 mmHg) and “normal” blood pressure (<120/80)?

In a recent meta-analysis of 25 different studies, patients with a history of cardiovascular disease but without clinically defined hypertension were treated with antihypertensive medications to lower their blood pressures a little anyway. Most of the patients started with blood pressures in the prehypertensive range. Treatment with antihypertensive drugs lowered blood pressure, as expected. It also lowered the risk of stroke (by 23%), heart attack (20%), congestive heart failure (29%) and death (13%), compared to patients treated with a placebo.

All of the patients in these studies had a prior history of cardiovascular disease. But the findings raise an interesting question: Would lowering the blood pressures of otherwise healthy people with prehypertensive blood pressures reduce their risk of ever developing cardiovascular disease in the future? You can bet that the drug companies are interested. Think of the potential increase in the market size for antihypertensive drugs if the drugs could be recommended for millions of healthy people, not just for patients with a history of cardiovascular disease!

Saturday, April 16, 2011

The Origins of Language

Where and when did human language originate? One way to tell is to analyze changing patterns in the number of phenomes – the distinct sounds that are used to form words - in languages around the world. According to recent research, the largest numbers of phenomes occur in languages in Africa, while the smallest are found in South America and Oceania. Coupled with knowledge of how and when human populations changed and migrated, the data are consistent with an African origin of language.

No surprise there, I guess. Modern humans originated in Africa, according to current thinking. This new data would imply that language developed before modern humans migrated from Africa more than 50,000 years ago. In fact the acquisition of language may have been what gave modern humans a distinct evolutionary advantage, ultimately allowing us to colonize the entire world.

Thursday, April 7, 2011

Antibiotic Resistance Takes a New Turn

A strain of bacterium called Klebsiella pneumoniae that causes blood infections and pneumonia has now developed resistance to the one remaining group of antibiotics that used to be effective against it, called carbapenems.

Especially worrisome is that K. pneumoniae is the first gram-negative bacterium of any significance to develop antibiotic resistance. Gram-negative bacteria exchange DNA with other bacteria more readily than do gram-positive bacteria such as methycillin-resistant Staphylococcus aureus (MRSA). (Gram-negative and gram-positive refer to whether the bacterium takes up a particular stain, and that is determined by differences in cell wall structure). The danger is that an antibiotic-resistant strain of K. pneumoniae might transfer the gene for antibiotic resistance to other gram-negative bacteria such as the much more common E. coli. And that would mean that antibiotic resistance would spread from one strain of gram-negative bacterium to another even though the bacteria were never exposed to the antibiotic at all.

It’s been just over 80 years since penicillin was first introduced, and despite the development of many new antibiotics over the years, the bacteria seem to be winning the battle. In recent years the development of new antibiotics has slowed to a trickle, to the point that there are no new types of antibiotics even in the drug-development pipeline. Pharmaceutical companies have lost interest in developing new antibiotics, in part because they know that antibiotic resistance is likely to render any new antibiotic less useful with the passage of time.

What to do? Can we research ourselves out of this dilemma, or are we doomed to remain one step behind in the perennial battle against bacteria?

Reference: McKenna, Maryn. The Enemy Within. Scientific American April 2011, pp. 46-53.

Monday, April 4, 2011

Treating Radiation Exposure

The nuclear power plant in Fukushima, Japan that was damaged last month by the tsunami continues to release radioactive materials into the atmosphere and the ocean. A few workers who were trying to stop the leaks have been exposed to excessive doses of radiation. Lots of folks are asking: How does radiation damage the body, and are there any drugs to combat radiation poisoning?

At the cellular level, excessive radiation exposure leads to the production of highly reactive oxygen species called free radicals. The free radicals damage DNA, leading to cell death. Rapidly-dividing cells such as those in the bone marrow and lining the digestive system tissues are the most affected. But death from radiation poisoning is usually due to multiple organ failures, making it difficult to treat.

So far there aren’t any truly effective drugs to treat radiation poisoning, though several are under development. The major pharmaceutical companies traditionally haven’t been interested in developing anti-radiation drugs because there isn’t supposed to be a market for them, aside from the rare nuclear accident. Perhaps in the wake of the accident in Japan, that attitude will change.

Saturday, April 2, 2011

Tackling Obesity

The basic formula for losing weight is simple; eat fewer calories than you expend over the same time period and you’ll lose weight. So why has the obesity problem in the United States continued to grow? Why is it so hard to eat fewer calories than one expends?

There are lots of reasons. When we try to eat too few calories, our brains fight against the calorie shortage, encouraging us to eat. Our metabolism may decline when we are in “starvation” mode. Junk food is cheap and plentiful. Marketers are skilled at selling us food that is profitable, even if unhealthy. We’re encouraged by friends and families to eat. We don’t get enough exercise…the list goes on and on.

Is there a solution? According to a recent article in Scientific American, the solution is not likely to come from more knowledge about metabolic processes or even from a diet pill. Taking off those extra pounds and keeping them off over the long run will probably require the application of behavioural modification principles combined with consistent peer support (think Alcoholics Anonymous and Weightwatchers). Changes in government policy that encourage healthy eating, such as requiring calorie counts on restaurant menus, banning trans-fats from deep-fryers, or taxing sugary drinks would help as well.

Reference: Freedman, David H. How to Fix the Obesity Crisis. Scientific American Feb. 2011, pp. 40-47.