Biomedical subjects

J W Hoffman

Publications and source records attributed to J W Hoffman.

11 recordsLinked to original sources

PubMed2002

Cold agglutinins complicating repair of aortic dissection using cardiopulmonary bypass and hypothermic circulatory arrest: case report and review.

Cold agglutinins (CAs) are autoantibodies that react reversibly with red blood cells (RBCs) at temperatures of, or below, the thermal amplitude for agglutination. This results in increased blood viscosity and sludging of RBC, and may impair perfusion to various organ systems. Although this phenomenon appears rarely in the clinical arena, the incidence of CA is increased substantially in cardiac surgery due to the routine use of hypothermia for organ preservation and systemic metabolic reduction. Once activated, CA are associated with microvascular occlusion, hemolysis, complement fixation, renal and hepatic insufficiency, cerebral insult, and myocardial infarction. Complications from CA may be minimized with appropriate screening, detection, and management in the perioperative period. A prototypical case is described, and pertinent issues regarding CA are reviewed.

Aged↗

PubMed1984

Morphologic changes in rat urothelial cells during carcinogenesis: I. Histologic and cytologic changes.

The methods of either image or flow cytometry applied to developing bladder tumors in rats requires satisfactory cell samples and a system for cell classification that is related to the lesions from which the cells are derived. Seven- to eight-week-old male Fisher 344 rats were fed 0.05% of the carcinogen N-butyl-4-N-hydroxybutylnitrosamine (BBN) in drinking water for 10 wk and then returned to tap water. Animals were killed at 14, 26, 34, 45 and 62 wk after the start of carcinogen feeding. Age-matched untreated animals were controls. Bladders were fixed, embedded, sectioned, and histologically evaluated, or were dissociated with a trypsin/EDTA solution into single cells that were Papanicolaou stained and evaluated for cytopathologic changes. Overnight urines were collected before killing; urine sediments were Papanicolaou stained and evaluated. Histologic features were hyperplasia at 14 wk, followed by slowly progressing papillary transitional cell tumors that eventually led to invasive carcinoma and were similar to those reported for this animal model. Treated animals had cytologic features of repair at 14 and 26 wk and neoplastic features at 45 and 62 wk. Both reparative and neoplastic changes were found at 34 wk. Cells were much more numerous in urines from treated rats (greater than 1,000 per sample) than in urines from controls (less than 1,000 per sample). Although exfoliated cells in urine samples were generally of poor quality, as many as 11% of cells were adequately preserved.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1982

Reduced sympathetic nervous system responsivity associated with the relaxation response.

Sympathetic nervous system activity was assessed in experimental and control subjects who were exposed to graded orthostatic and isometric stress during monthly hospital visits. After the first session, the experimental subjects practiced a technique that elicited the relaxation response. Their concentrations of plasma norepinephrine during subsequent graded stresses were significantly higher. No such changes were noted in the control group. These results were than replicated in the control group in a crossover experiment. The groups did not differ in their heart rate and blood pressure responses. These observations are consistent with reduced norepinephrine end-organ responsivity after regular elicitation of the relaxation response.

Adult↗

PubMed1982