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Biomedical subjects

T Hoffman

Publications and source records attributed to T Hoffman.

117 records · Page 7Linked to original sources

IgG on lymphocyte surfaces; technical problems and the significance of a third cell population.

Direct immunofluorescence performed with the F(ab)2 fragment of rabbit antibodies to IgG revealed that membrane bound IgG was only rarely found on the surface of small peripheral blood lymphocytes (PBL). In contrast whole antibodies to IgG used in fluorescence gave much higher levels of cells with IgG surface staining. This staining resulted from secondary IgG binding, in part due to the uptake of newly formed immune complexes. IgM-and IgD-bearing cells were brightly stained in relatively similar percentages by both the whole and F(ab)2 forms of the class-specific antibodies; they constitute the principal membrane Ig of PBL. Evidence was obtained indicating that a special population of cells with Fc receptors but lacking membrane Ig was primarily involved in the high IgG binding. This population also formed sheep erythrocyte rosettes when optimal conditions were utilized.

Animals↗

Acute embryopathic effects of ethanol in the Long-Evans rat.

Thirty-two pregnant Long-Evans rats were divided into 10 groups of 3 or 4 pregnant rats, and each rat was given a single dose of 4 ml ethanol/kg (20 ml/kg of a 20% solution) between d 6 and 15 of gestation. An 11th group of 50 pregnant rats received distilled water and served as controls. Offspring body weights were decreased in groups of rats given ethanol as compared to controls (3.0-3.6 g, versus 3.9 g for controls). Total litter weight was decreased in dams given ethanol on d 6. Skeletal variants were seen in 13-78% of the offspring given ethanol, compared to 0.6% of the controls. Variations may be considered as additional signs of embryotoxicity. Malformations such as hydronephrosis, pelvic kidney, microcephalus, cranioschisis, and microphthalmia occurred in 72-100% of the ethanol treated offspring, as compared to 12% of controls. Hydronephrosis was most frequent on d 9 or 14, pelvic kidney on d 8 and 11, and microphthalmia from d 10-12. Cranioschisis was maximal on d 7, 11, and 15, and microcephalic offspring were most frequently born to dams given ethanol on d 7 or 14. Skeletal defects were usually single entities, while soft-tissue anomalies occurred in a consistent pattern. These results suggest that ethanol is a stage-specific teratogen in the rat at comparable exposure levels attained by many humans.

Abnormalities, Drug-Induced↗