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Biomedical subjects

M Alter

Publications and source records attributed to M Alter.

179 records · Page 10Linked to original sources
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Medical registers as historical controls: analysis of an open clinical trial of inosiplex in subacute sclerosing panencephalitis.

Clinical trials of treatments for rare or fatal diseases must often use historical rather than randomized concurrent controls. Randomized trials may not be possible if (1) the number of patients available is quite small, (2) ethical considerations discourage the assignment of patients to control treatments known to be ineffective or (3) some evidence suggests that the proposed new treatment is substantially more effective than the control. We suggest that, when randomization is not feasible, adequately maintained medical registers can serve as a source of control patients. Investigators must pay careful attention to prognostic factors that might bias the results. However, statistical techniques for controlling such bias exist and, if these are properly employed, registry-derived historical controls can be used to evaluate the effectiveness of treatment.

Clinical Trials as Topic↗
PubMedDate not supplied

How is Creutzfeldt-Jakob disease acquired?

Creutzfeldt-Jakob disease (CJD) is one of several related disorders collectively called prion diseases. These disorders affect man and animals and are now known to be caused by the abnormal configuration of a naturally occurring protein, PrP(c). By mechanisms still not well understood, this natural protein is converted into a pathologic variant, PrP(sc). The disease is 'acquired' spontaneously perhaps by posttranslational conversion of a PrP(c) into a PrP(sc) population. This sporadic form of CJD has been reported worldwide with a frequency of 1/million. Other modes of acquisition include the following: ingestion of brain tissue from deceased victims through ritual cannibalism at burial ceremonies formerly (and no longer) practiced by New Guinea Highlanders; iatrogenically, through corneal transplants from infected donors, inoculation of human growth hormone and gonadotropin prepared from infected human pituitary glands; from inadequately sterilized depth electrodes introduced neurosurgically into the brain during workups of patients with epilepsy, and applications of infected dura mater in neurosurgical procedures. Most recently, an infected bovine source (bovine spongiform encephalopathy) has been implicated and produces a new variant of CJD. Clusters of CJD in families in some populations have been recognized which are inherited in Mendelian fashion. These clusters are related to mutations of the PRNP gene in specific codons (e.g. codon 200). Homozygosity for these mutations increases the chances of manifesting the disease. Other potential methods of acquisition, such as by blood transfusion, surgical sutures, tonometers, consumption of hog brain or other organs and tissue, remain unproven.

Animals↗
PubMedDate not supplied

Stroke in the Lehigh Valley: seasonal variation in incidence rates.

We investigated the seasonal pattern of stroke using the Lehigh Valley Stroke Register. This register includes all patients hospitalized with stroke or transient ischemic attack (TIA) from among the 600,000 Lehigh Valley residents. Meterological data were obtained from the National Oceanic and Atmospheric Administration. The study, which uses 18 months of data, included 1,944 cases. Using single harmonic regression analysis, the seasonal pattern of TIA and infarction, but not hemorrhage, fit a sine-cosine wavefunction with a 12-month period (R2 = 41% and 36%, respectively). For infarction, the strongest seasonal pattern was exhibited for women of all ages and for both sexes in the age groups 65-74 and 75-84, but only the sine component was significant. The peak months for TIA were June-August, while the peak months for infarcts were February-April. Correlations between ambient temperature and each type of stroke were computed. A significant positive correlation for TIA was found (r = 0.57, p = 0.01). After adjusting for a 2-month lag between the low for infarction and the peak for temperature, a significant negative correlation was found (r = -0.64, p = 0.01). No significant correlation was found for hemorrhage. Possible reasons for the opposite relations of TIA and infarct are discussed.

Age Factors↗
PubMedDate not supplied

Acute stroke, hematocrit, and blood pressure.

A population-based study of the relation between hematocrit and stroke subtype was carried out among 2,077 individuals using the Lehigh Valley Stroke Register. This register identifies all stroke patients admitted to the 8 acute care hospitals serving the Lehigh Valley area of eastern Pennsylvania-western New Jersey. The mean hematocrit was higher in patients with lacunes than with thrombotic or embolic strokes (p = 0.02). However, when blood pressure was also considered the increase in hematocrit in patients with lacunar stroke was significant only when systolic hypertension (greater than or equal to 150 mm Hg) was also present (p = 0.029); no significant difference in hematocrit was found between stroke subtypes in normotensive individuals. Therefore, we cannot exclude the possibility that hypertension interacts with hematocrit in accounting for the observed association with lacunar infarcts. There was no trend for increased in-hospital mortality for stroke patients in either the low (less than or equal to 30, 30-36%) or high (greater than or equal to 47%) hematocrit groups.

Acute Disease↗
PubMedDate not supplied

Effect of cyclandelate on dementia.

Cyclandelate, a vasodilator, was administered to 24 patients with dementia. The dementia in these patients was presumed to be due to cerebral ischemia caused by atherosclerosis in cerebral vessels after other possible causes were ruled out. In a double-blind, cross-over study, patients received 200 mg of cyclandelate four times daily for six weeks and a placebo for six weeks. Six psychological tests, which reflect various aspects of higher cortical ability, were used to evaluate the effect of cyclandelate on the dementia. Cyclandelate was found to be no more effective than placebo in improving higher cortical function in these demented patients.

Aged↗
PubMedDate not supplied

The Lehigh Valley Stroke Program: establishing a communitywide, hospital-based stroke register.

A communitywide, hospital-based stroke register has been established in the Lehigh Valley of Pennsylvania and New Jersey. The Lehigh Valley has about 600,000 inhabitants and is geographically somewhat isolated. Ninety-five percent of the people are white, and the population has an age-sex distribution like that of the United States as a whole. All patients falling into any of nine diagnostic categories of stroke or transient ischemic attack are registered on admission to a hospital, and medical, social, and demographic data are abstracted onto precoded data forms. A single neurologist assigns definitive diagnoses according to standardized criteria after reviewing all of the medical data. The stroke register provides a new and powerful tool for collecting population-based data on a large number of cases in a short-time. After adjusting for demographic differences, epidemiologic studies can be carried out that may be generalizable to the entire United States. Several organizational aspects of the register and its operation are described in this report, and examples of the types of information and statistics readily calculable from the data in the register are given. The completeness of the stroke ascertainment and the large population registered also offer an excellent opportunity for any interested researcher to investigate the relationships between medical, social, and demographic conditions on the one hand and stroke risk on the other; to study the efficacy of prevention and treatment programs; and to determine health care provision requirements in a well-defined population.

Age Factors↗