Editor's Note: Science Scan is a roundup of recently published, biotechnology-relevant research.
Shakespeare's Macbeth said it best: "Sleep that knits up the ravell'd sleeve of care."
What the U.S. National Institutes of Health (NIH) says is that more than 70 million Americans suffer from frequent insomnia. Its symptoms include difficulty falling asleep, awakening often during the night, waking too early in the morning, inability to go back to sleep or not waking up feeling refreshed.
According to the National Sleep Foundation, 37 million older Americans have frequent sleep problems that, if ignored, can complicate the treatment of several more serious medical conditions confronted by the elderly, including arthritis, diabetes mellitus, heart and lung disease, and depression. Poor sleep among older adults often goes unnoticed by the medical community. Although the majority of older adults (67 percent) complain of frequent sleeplessness to friends, relatives or physicians, only about 7 million cases have been diagnosed.
The U.S. market for prescription sleep products, specifically central nervous system agents for treating insomnia, was approximately $1.5 billion in 2002. That market grew at a rate of almost 25 percent during the past two years.
A large-scale, long-term 70-center clinical trial of an experimental insomnia drug called eszopiclone is reported in the November issue of Sleep, a peer-reviewed publication of the Associated Professional Sleep Societies. The article is titled "Sustained efficacy of eszopiclone over six months of nightly treatment: Results of a randomized, double-blind, placebo-controlled study in adults with chronic insomnia." (Eszopiclone's brand name is Estorra.)
Patients 21 to 69 years of age with chronic insomnia received nightly treatment with either placebo (195 subjects) or eszopiclone (593) participants. Efficacy endpoints included: patient reporting sleep latency (onset of drug action), total sleep time, sleep-maintenance measures (wake time after sleep onset), number of awakenings, number of nights awakened, quality of sleep and next-day ratings of ability to function - that is, daytime alertness and physical well-being. There was no evidence of tolerance to the drug, and the commonest adverse events were unpleasant taste and headache, the paper noted.
Eszopiclone has been developed and is produced by Sepracor Inc., of Marlborough, Mass. A new drug application for the insomnia drug is now under review with the FDA. The NDA contains a total of 324 clinical trials, which included more than 2,700 adult and elderly subjects, and more than 60 preclinical studies. A total of six randomized, placebo-controlled Phase III efficacy studies, including one with a positive control, in chronic or transient insomnia were conducted in both adult and elderly patients. The Sleep article concluded, "This placebo-controlled study of eszopiclone provides compelling evidence that long-term pharmacologic treatment of insomnia is efficacious. This evidence for sustained efficacy contrasts with the commonly held view that hypnotics are ineffective in the long-term treatment of insomnia."
Identical Twins Of MS Patients In Canada Likely To Develop Multiple Sclerosis, But Only Females
A large-scale study of twins and multiple sclerosis elucidates the relative contributions of genetics and environment to this devastating disease. MS, marked by the progressive loss of neural function, is one of the most prevalent neurological diseases affecting young adults. Previous studies of twins affected by the condition suggest that both genetic and environmental factors contribute to MS. Because these studies were small, however, they could not rule out certain factors, such as the phenomenon of twinning itself increasing the risk of multiple sclerosis.
A recent article in the Proceedings of the National Academy of Sciences (PNAS) dated Sept. 30, 2003, is titled "Twin concordance and sibling recurrence rates in multiple sclerosis." Its co-authors are in the Canadian Collaborative Study Group.
They undertook a two-decade project analyzing more than 400 pairs of twins. Their sample included 75 percent to 80 percent of all the twins in Canada with MS. They found that the twinning rate in MS patients is similar to the rate observed for the Canadian population as a whole. That suggested that twinning itself is unrelated to multiple sclerosis risk.
Furthermore, the frequency of a certain HLA-DR15 allele implicated in MS development was the same in twin and non-twin MS patients. The identical twin of an MS patient was much more likely to develop the disease than a nonidentical twin. However, this effect was limited to females. The results indicate that genetic factors contribute to development of MS and help explain why females get the disease more often than males. In addition to genetic factors, there may be a role for gestational factors because nonidentical, or fraternal, twins were more likely to get MS than non-twin siblings.
There's More To Ozone Than Pie In Sky; Don't Overlook Atherosclerosis Menace In Arteries
As if the threat of the expanding ozone layer in the stratosphere is enough, here's another warning on the its rap sheet - right in your blood circulation. Scientists have now learned that ozone (O3) may also contribute to hardening of the arteries in humans. "Evidence for ozone formation in human atherosclerotic arteries" is the title of their paper in Scienc, released Nov. 4, 2003.
The discovery that the highly reactive chemical gas is produced in living organisms "changes the landscape" of oxidation chemistry research, according to the paper's co-authors. The group analyzed fatty plaques from diseased arteries and detected molecules that can be produced only when cholesterol is broken down by ozone. Lab tests confirmed that ozone appeared when plaque tissue interacted with immune system cells and that the "oxysterols" could contribute to cellular damage in diseased arteries.
This offers a possible link between the seemingly disparate factors that contribute to atherosclerosis: namely, cholesterol accumulation, inflammation and cellular damage. The authors add that testing for oxysterols in the blood might one day offer a noninvasive way to detect arterial disease.