ß-amyloid peptide, found in the brains of patients with Alzheimer's disease, can disrupt brain signals and may contribute to memory loss, according to a study in the January Journal of Neuroscience. The ß-amyloid peptide blocks the function of a key signaling receptor, the nicotinic acetylcholine receptor, in the hippocampus. The authors suggested that the plaques seen in the brains of Alzheimer's patients may be a cause rather than a result of the disease.

Eighty-five percent of neurologists surveyed prescribe dopamine agonists as a first-line treatment for Parkinson's disease. The survey of 205 neurologists was conducted by Hospital Research Associates at the 52nd Annual Meeting of the American Academy of Neurology. Other findings were that 93% of those surveyed cite dyskinesias as a problem for Parkinson's disease patients on levodopa therapy, 77% believe that initial therapy with second generation dopamine agonists helps delay the development of dyskinesias, and 79% choose to start younger Parkinson's disease patients on dopamine agonists.

Epilepsy in children may be a pervasive condition that includes both seizures and behavioral problems, according to the findings in the January 2001 Pediatrics. The study compared the behavior of 224 children, between age 4 and 14, with a first recognized seizure, and their 135 healthy siblings. The authors noted that children with epilepsy had "significantly higher Total, Internalizing, Attention, Thought, and Somatic Complaints problem scores than their nearest-in-age healthy siblings."

Long-term treatment with verapamil could prevent cardiomyopathy in patients with muscular dystrophy, according to a study in the January 15 Journal of Clinical Investigation. The study used genetically modified mice as models for limb-girdle muscular dystrophy. In the mouse models, this genetic defect caused the degradation of the dystrophin-glycoprotein complex of the vascular smooth muscle. "In smooth muscle, we saw that the complex was disrupted. We found there were constrictions in the blood vessels in this animal model," said Kevin Campbell, PhD, lead researcher. When the mice were taken off verapamil, cardiomyopathy started immediately.

Light to moderate alcohol intake is associated with a reduced risk of ischemic stroke in young women, according to a study published in the January Stroke. The population-based case-control study of women age 15 to 44 showed that alcohol consumption, up to 24 g/d, was associated with fewer ischemic strokes than was no alcohol consumption. Wine gave the most protection of all alcohol types.

Higher consumption of fish and omega-3 polyunsaturated fatty acids is associated with a lower risk of thrombotic infarction, primarily among women who do not regularly consume aspirin, according to a study in the January 17 JAMA. The researchers followed 79,839 women, age 34 to 59 at baseline, for 14 years. "Among stroke subtypes, a significantly reduced risk of thrombotic infarction was found among women who ate fish two or more times per week [51%]," the authors wrote. "Women in the highest quintile of intake of long-chain omega-3 polyunsaturated fatty acids had reduced risk of total stroke and thrombotic infarction [28% risk reduction for total stroke and 33% lower risk for thrombotic infarction]."

Relaxation training and thermal biofeedback are promising treatments for pediatric headache, according to a study in the January 9 Neurology. Twenty children diagnosed with migraine were taught deep breathing, progressive muscle relaxation, and guided imagery in a training session. By the second follow-up visit, children were able to raise their peripheral body temperature by 3.7°F. Headache severity decreased, as well as frequency (12.9 to 9.7 days/month) and duration (6.9 to 5.2 hours). "We believe the biofeedback-assisted relaxation training techniques, in conjunction with lifestyle and traditional drug therapies, have the potential to reduce the frequency and severity of headaches in children and to improve school attendance," according to study author Scott W. Powers, PhD.

Risk for developing Alzheimer's disease is elevated in African-Americans and Caribbean Hispanics, according to researchers. The seven-year study, in the January 9 Neurology, was based in the Washington Heights and Inwood communities of New York City. "Neither clinically apparent cardiovascular or cerebrovascular disease contributed to the higher incidence rates of Alzheimer's disease in African-American and Caribbean Hispanic individuals compared to white individuals," wrote the authors.

Hypertension, smoking, and female sex increase the likelihood that an individual with an expressed familial intracranial aneurysm will have an aneurysm, report the authors of a study in the January Neurosurgery. The survey of 24 families with at least two affected siblings showed that affected family members with familial intracranial aneurysms exhibited prevalence rates of smoking and hypertension (74% and 43%, respectively) that tended to be higher than those of population-based controls (52% and 36%, respectively).

A primary alteration in the glial fibrillary acidic protein (GFAP) may cause Alexander's disease, according to a study in the January 3 Nature Genetics. The pathologic hallmark of the disease is the presence of cytoplasmic inclusions in astrocytes that contain the GFAP in association with small heat-shock proteins. The authors conclude that Alexander's disease "represents the first example of a primary genetic disorder of astrocytes, one of the major cell types in the vertebrate CNS." The researchers are uncertain if these aggregations are a byproduct or a cause of the disease.

Functional imaging results are misinterpreted when the resting brain neurotransmitter activity is neglected, according to a study in the January American Journal of Psychiatry. In the awake, resting, and unstimulated states, 70% to 80% of brain energy consumption is devoted to the same glutamate/glutamine neurotransmitter signaling as are the small percentages stimulated by tasks. "The ability to quantitate neurotransmitter activity both in the presence and absence of stimulation highlights and provides a criticism of the psychological assumptions behind the standard interpretation of images," said study author Robert Shulman, PhD.

Using magnetic resonance imaging (MRI) to look at alterations in resting activity in the subregions of the hippocampus allows researchers to pinpoint changes in brain activity that may underlie memory impairment, according to a study in the December Neuron. As well, the use of MRI to map blood oxygenation in the brain at rest could lead to more effective treatment for memory loss in its early stages. "This is encouraging data. We may be able to use this technique as an early diagnostic for Alzheimer's disease," said lead author Scott A. Small, MD.

Mirror movement, a rare disorder first described in 1889, has been linked to protein ephrin-B3, in a mouse model, according to an article in the January Neuron. The mice, which completely lack protein ephrin-B3, have a kangaroo-like hopping gait, and they have difficulty swimming and grooming. "Ephrin-B3 is a very important molecule as it is expressed down the middle of the spinal column," said lead author Mark Henkemeyer, MD. "It serves as a repulsive barrier that keeps the left axons on the left side of the nervous system and the right axons on the right."

Spinning and whirling by autistic children is not linked to damage to the cerebellum, which is the brain's control center for movement, balance, and equilibrium, according to a recent study. The eye movements of 13 autistic children age 7 to 17 functioned the same after spinning as did those of non-autistic children, according to a study in the December 2000 Journal of Autism and Developmental Disorders. "This tells us that those parts of the cerebellum that govern our ability to restore balance operate normally in autistic children," said lead author Melissa Goldberg, PhD.

Abnormal activity of a-synuclein may be involved not only in inherited but also in non-inherited forms of Parkinson's disease, according to a study in the January Genome Research. The researchers established the DNA sequence of the chromosomal regions containing both human and mouse a-synuclein genes for comparative analysis. The research showed that a repeat element upstream of a-synuclein was identified and shown to be integral for normal expression of this Parkinson's-related protein.

Three new, separate, research studies in the December 22 Science suggest that a gene(s) on chromosome 10 may be a risk factor(s) for late onset Alzheimer's disease. These genes may affect the processing of the ß-amyloid protein. An author of one of the studies, Neill Graff-Radford, MD, said that when the gene is found, "depending on how frequently it does occur in the late-onset group, it's possible we may be able to identify people at risk and treat them before they get the disease."

Antigen-specific immunotherapy is an effective treatment with no adverse side effects for a disease in monkeys that is similar to multiple sclerosis, according to a study in the February Journal of Immunology. Although T cells that are exposed to small amounts of myelin are stimulated to attack the myelin sheaths, T cells that are exposed to large amounts of myelin (or any antigen) self-destruct. Thus, the introduction of large amounts of myelin should cause T cells to self-destruct. "The therapy is counterintuitive; one might think it would be like pouring gasoline on a fire," said senior author Michael Lenardo, MD. "In this case, adding more antigen smothers the fire." He and colleagues are also studying the use of antigen-specific immunotherapy for other autoimmune diseases such as myasthenia gravis.

Brain pathology does not necessarily correlate with dementia, indicate preliminary results from a community-based study in England and Wales. Among the first 209 individuals who have undergone necropsy, cerebrovascular (78%) and Alzheimer-type (70%) pathology were common. Dementia was present in 48% of subjects, of whom 64% had features indicative of Alzheimer's disease. Dementia was not present in 52%, of whom 33% had similar densities of neocortical neuritic plaques. "The most important finding of this study was the extensive overlap of intermediate Alzheimer-type pathology among demented and non-demented older people despite equivalent degrees of vascular pathology," said the authors in the January 20 Lancet.

Partial epileptic seizures that manifest as acute fear may be misdiagnosed as panic attacks, according to researchers in Paris. Neuroimaging may help differentiate seizures from panic attacks, they said in the February Journal of Neurology, Neurosurgery, and Psychiatry. In study participants, epilepsy was localized to the right temporal, left temporal, bitemporal, or frontal zones. However, intense ictal fear involves the orbitoprefrontal, anterior cingulate, and temporal limbic cortices, noted the authors.

Bias in the Systolic Hypertension in the Elderly Program (SHEP) Trial (1985–1990) was explored in the January American Journal of Epidemiology. (The SHEP study had indicated that active treatment was more effective than placebo in reducing the incidence of cardiovascular events, but not the incidence of dementia and disability.) The authors reported that differential dropout in SHEP biased cognitive and functional evaluations toward the null effect. "This might have obscured the appraisal of a protective effect of treatment on the cognitive and functional decline of older hypertensive adults," they concluded.

NR