NEWS ROUNDUP
New and Noteworthy Information

Despite common assumptions, melatonin levels may not change with age, according to a report in the November American Journal of Medicine. Nighttime levels in 34 men and women ages 65 to 81 were comparable to those in 98 younger men between the ages of 18 and 30. While some older people have low melatonin levels, it is not because of their age, per se, said researcher Jamie M. Zeitzer, PhD.

Tube feeding does not prolong survival of dysphagic demented patients, according to a study in the October 13 JAMA. A review of randomized trials from 1966 through March 1999 found no evidence that tube feeding reduces the risk of aspiration pneumonia or infection, improves function or mitigates decline, or improves comfort in this patient population. Aspiration pneumonia was, however, the most common adverse effect of tube feeding. "A comprehensive, motivated, conscientious program of hand feeding is the proper treatment" for these patients, the researchers concluded.

The gene for Huntington disease is associated with a lower incidence of cancer, reported Danish researchers. They analyzed data from 694 patients registered with The Danish Huntington Disease Registry, along with data from the patients' relatives. Environmental factors, medication, diet, and means of diagnosis were linked to neither an increase nor a decrease in cancer risk. In the October 1 Cancer, the researchers suggested that the lower risk of cancer may be an apoptotic effect of an expanded polyglutamine tract.

Highly active antiretroviral therapy ameliorates neurocognitive impairment in HIV-infected patients, according to a study in the October AIDS. A multicenter team studied 26 patients who took a protease inhibitor and two reverse transcriptase inhibitors. At six and 15 months all areas of neuropsychological functioning were improved. "The reversibility of neurological dysfunction confirms that viral replication in the brain is necessary to induce clinical and pathological neurological abnormalities," said the authors.

Osteopathic spinal manipulation and standard allopathic treatment had similar benefits in patients with recent-onset, subacute low back pain, according to a report in the November 4 New England Journal of Medicine. The 83 patients in the osteopathic group received eight treatment sessions; treatment options in the standard-care group (72 patients) may have included analgesics, anti-inflammatories, diathermy, hot or cold packs, use of a corset, or transcutaneous nerve stimulation prescribed over eight visits. The study authors recommended initiation of a formal cost-benefit analysis.

Working memory deficits in multiple sclerosis (MS) may be the result of impaired speed rather than accuracy. Eighty-one patients with clinically definite MS and 36 healthy controls completed the auditory threshold serial addition test (AT-SAT) or the visual threshold serial addition test (VT-SAT). According to the study, published in the November Journal of Neurology, Neurosurgery, and Psychiatry, the MS group had significantly longer interstimulus intervals than the healthy controls, particularly on the AT-SAT. But scores were indistinguishable when time restrictions were removed.

Multiple system atrophy is indicated by development of either symptomatic orthostatic hypotension or urinary incontinence during the first year after the differential diagnosis of parkinsonian syndrome, suggested results of a multicenter study reported in the November Journal of Neurology, Neurosurgery, and Psychiatry. Seventy-seven pathologically confirmed cases of Parkinson's disease in Austria, France, the United Kingdom, and the United States were studied to improve the differential diagnosis of the disease. The study was the first to investigate both frequency and time course of symptomatic orthostatic hypotension and urinary incontinence in Parkinson's disease, multiple system atrophy, dementia with Lewy bodies, corticobasal degeneration, and progressive supranuclear palsy.

Verbal memory impairment at time of diagnosis of partial epilepsy is a predictor of seizure outcome, according to a Finnish study in the November Epilepsy Research. Adults (n=89) recently diagnosed with partial epilepsy were evaluated for presence of EEG spike focus, partial complex or mixed seizure type, remote symptomatic etiology, moderately impaired memory performance in immediate recall and in delayed recognition of word list, and age at diagnosis. After two years, this model correctly predicted seizure outcomes in 94% of cases.

Recent heavy drinking may promote cardiogenic brain embolism, according to a report in the November Stroke. Consumption of more than 151 g of alcohol in a week increased the risk of cardioembolic and cryptogenic stroke, while consumption of more than 40 g within 24 hours increased the risk of cardiogenic embolism, tandem embolism, and cryptogenic stroke among identified risk groups. Neither light drinking nor former heavy drinking were risk factors for cardioembolic stroke.

General neurologists' and MS specialists' quality of care and clinical characteristics were perceived as very similar by their patients with MS. However, there were differences in symptom management, according to a report in the October Neurology. The MS specialists "may have had more expertise in use of and advice to patients about new treatments and management of side effects, better perceptions by patients on communication issues, and higher patient involvement in some types of research studies and access to multiple sclerosis care in a few areas," the authors noted. Future studies, they added, are needed to evaluate which factors are actually related to optimal quality of care.

New transgenic mice carrying the human genetic coding for tau protein will facilitate the study of Alzheimer's disease, according to a report in the November Neuron. The transgenic mice developed tau lesions and tangles and showed evidence of nerve cell degeneration and impaired movement. Further study may help identify how tau-containing tangles relate to the development and progression of Alzheimer's disease.

Controlled-release melatonin may facilitate discontinuation of long-term benzodiazepine therapy, suggests a report in the November 8 Archives of Internal Medicine. Thirty-four patients took melatonin (2 mg) or placebo and were encouraged to taper benzodiazepines over six weeks. During a second six-week period, all participants took melatonin. By the study's end, 24 patients had stopped benzodiazepines and reported good sleep quality, while some of the remaining 10 had reduced their daily dose.

A"snippet of DNA" in the genetic blueprint of every human resembles a gene sequence from the human immunodeficiency virus, according to a report in the November 9 Proceedings of the National Academy of Sciences. This link offers insight into the evolution of both humans and viruses, and suggests that HIV may have been around much longer than previously thought, said researcher Bryan Cullen of Duke University. The discovery could also have implications for xenografts, he added, and for developing "better strategies for countering the threats of viral infection."

Depression rivals smoking as a risk factor for new disease among older Americans, reported researchers from the University of Michigan. The population-based study included 6,000 Americans ages 70 and older who were assessed in 1993 and 1995. Participants who were unable to walk several blocks, climb stairs, or lift a 10-pound object were 50% more likely to develop a new disease in the following two years than physically fit subjects; multiple symptoms of depression or smoking raised the risk by 34%; and a high body mass index by 18%.

A frontal variant of Alzheimer's disease (AD) with distinctive clinical and pathologic features is suggested by a University of California study. In the October Archives of Neurology, researchers reported a higher-than-expected degree of neurofibrillary tangle (NFT) pathology in the frontal lobes in a subgroup of AD patients who presented in early stages of dementia with disproportionate impairment on tests of frontal lobe function. Neuropsychological profiles and senile plaque and NFT accumulation in the frontal, entorhinal, temporal, and parietal cortices were compared in three patients with frontal AD and three matched patients with typical AD.

Early treatment of relapsing-remitting MS may slow the progression of brain atrophy, according to a report in the November 10 Neurology. Researchers examined magnetic resonance images from 140 participants in a placebo-controlled trial of interferon beta-1a (Avonex^®). Using a new technique to measure brain atrophy, the researchers found that active treatment preserved brain tissue during the second year; the discrepancy between treatment and placebo groups "was about 50%."

Formation of new neurons has been documented in the cerebral cortex of adult monkeys, according to a Princeton University study. After injection of the chemical tracer BrdU into adult rhesus monkeys, neurons with DNA containing BrdU were detected in the monkeys' brains, confirming that the cells formed after the tracer was injected. Evidence of neurogenesis was found in three areas of the cerebral cortex—the prefrontal region, the inferior temporal region, and the posterior parietal region. Neurogenesis in the cognitive and executive areas of the adult monkey brain, the researchers pointed out, has major implications for theories of human brain development and for the possibility of future therapies for the damaged human brain.

Fetal surgery to repair myelomeningocele reduces neonatal risk of hydrocephalus and hindbrain herniation, according to two research teams from the Vanderbilt University, Nashville, and the Children's Hospital of Philadelphia. The independent studies, published in the November 17 JAMA, were accompanied by an editorial by Joe Leigh Simpson, MD, who described them as encouraging yet controversial, due to selection bias and arguable outcomes. He noted that "a clear demonstration of greater success in fetal outcome and fewer obstetrical complications are necessary" before the procedure can be widely recommended.

—Kathryn Blair
Associate Editor