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Biomedical subjects

W R Bennett

Publications and source records attributed to W R Bennett.

4 recordsLinked to original sources
PubMed1987

Activation of the complement system by recombinant tissue plasminogen activator.

Recent trials have shown that recombinant tissue plasminogen activator (rt-PA) is an effective thrombolytic agent in patients with acute myocardial infarction. Because rt-PA converts plasminogen to plasmin, which is known to activate complement in vitro, we tested the hypothesis that rt-PA can induce in vivo activation of complement. Studies were performed in 12 patients with acute myocardial infarction. Six control patients had patent coronary arteries and did not receive rt-PA; these patients had normal values of the components of the complement system C4a (409 +/- 111 ng/ml) and C5a (8.8 +/- 1.8 ng/ml) with a slight elevation of C3a (204 +/- 6.6 ng/ml) in samples collected before coronary arteriography (253 +/- 25 minutes after onset of pain). After coronary arteriography, there was a slight decrease in the values of C4a (224 +/- 37 ng/ml), C5a (7.3 +/- 1.3 ng/ml) and C3a (164 +/- 35 ng/ml). The remaining six patients had complete coronary occlusion and received rt-PA (80 to 150 mg intravenously). In this treated group, before coronary arteriography the values of C4a (406 +/- 51.6 ng/ml) and C5a (8.1 +/- 1.9 ng/ml) were normal, and those of C3a were slightly elevated (250 +/- 76 ng/ml). All complement values obtained before rt-PA were similar to those in the untreated group. However, after administration of rt-PA (but before any angiographically detectable reperfusion), there was a striking increase in C4a (2,265 +/- 480 ng/ml; p less than 0.01), C3a (600 +/- 89 ng/ml; p less than 0.05) and C5a (30.0 +/- 4.5 ng/ml; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1984

Rhabdomyolysis in thyroid storm.

This is the first reported case of thyroid storm complicated by rhabdomyolysis with acute reversible renal failure. The only possible causes for the rhabdomyolysis were inherent features of thyroid storm. Although hyperthyroid patients characteristically have normal or low serum levels of muscle enzymes, this case report demonstrates that rhabdomyolysis with elevated serum levels of muscle enzymes can occur with hyperthyroidism. An appreciation of the potential for rhabdomyolysis in hyperthyroidism should facilitate prompt initiation of aggressive therapy for myoglobinuria and thereby limit the severity of acute renal failure in these already very sick patients.

Acute Kidney Injury↗
PubMedDate not supplied

Reproductive and teratologic effects of electromagnetic fields.

The reproductive risks of electromagnetic fields (EMF) were evaluated based on an extensive review of the scientific literature pertaining to human epidemiologic studies, secular trend data, in vivo animal studies and in vitro studies, and biologic plausibility. The epidemiologic studies involving the reproductive effects of EMF exposures to human populations have included populations exposed to: (1) video display terminals (VDTs), and (2) power lines and household appliances. The clinical use of diagnostic MRI (magnetic resonance imaging) has been increasing, but there are few reports or studies of pregnant women or individuals of reproductive age who have been exposed to MRI, and whose reproductive performance has been evaluated. The population that has been studied most frequently are women exposed to VDTs, but their EMF exposures are extremely low and frequently are at the level of the ambient EMF in a house or office. The results of epidemiologic studies involving VDTs are generally negative for the reproductive effects that have been studied. Based on the number of studies, the exposure levels, and the fairly consistent results, it can be argued that VDT epidemiologic studies should no longer be given priority. There have been fewer studies concerned with the reproductive risks of power lines, electric substations, and home appliances. In some publications, positive findings for reproductive risks were reported, but the more consistent findings indicate that EMF, even at these higher exposures, do not generate a measurable increase in reproductive failures in the human population. When compared to other fields of human epidemiology, it is obvious that these studies have many difficulties. Exposures are rarely determined. Studies frequently involve small sample sizes and the investigators rarely have a combined expertise in EMF physics, engineering, and reproductive biology. Because of the allegation that there may be particular windows of frequency, wave shape, and intensity that may be deleterious, it is impossible to disregard low frequency EMF exposures as having no deleterious reproductive effects. Yet the epidemiologic data that are available would point in that direction. Secular trend data analysis of birth defect incidence data indicate that increasing generation of electric power during this century is not associated with a concomitant rise in the incidence of birth defects. There are over 70 EMF research projects dealing with animal and in vitro studies that are concerned with some aspect of reproduction and growth. Unfortunately, a large proportion of the embryology studies utilized the chick embryo and evaluated the presence or absence of teratogenesis after 48 to 52 hours of development.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗