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Biomedical subjects

T Baba

Publications and source records attributed to T Baba.

At least 595 records · Page 33Linked to original sources

Centrally mediated hyperglycemia by 6-aminonicotinamide.

Some metabolic changes induced by the intraventricular administration of 6-aminonicotinamide (6-AN) were studied in mice. Five or ten microgram/animal of 6-AN produced a marked hyperglycemia, lowered glycogen content in the brain and liver, and reduced the adrenal epinephrine content. Adrenalectomy or hexamethonium prevented 6-AN-induced hyperglycemia and decrease of glycogen content in the liver but not in the brain. Decrease of adrenal epinephrine content induced by 6-AN was overcome by hexamethonium. Pretreatment with 6-AN (10 microgram/animal) markedly lowered the toxic action, but not the hypoglycemic action, of a large dose of insulin.

6-Aminonicotinamide↗

Studies on angiopathy due to carbon disulfide. Retinopathy and index of exposure dosages.

The occurrences of retinopathy (microaneurysms/small dot hemorrhages) and the coded resting and postexercise ECG findings suggestive of coronary heart disease (CHD) were studied among 420 Japanese male workers exposed to carbon disulfide and 390 men not exposed to such a solvent. Retinopathy was detected in 24.4% of the exposed group and in 3.8% of the nonexposed group by color fundus photography. Among workers of the former group there was a significant correlation between retinopathy prevalences and the index of exposure dosages (r = 0.925, P less than 0.01). However, correlation between the prevalence of retinopathy and duration of exposure was not so high (r = 0.647, 0.10 less than P less than 0.25). The occurrences of coded resting and postexercise "coronary" ECG findings were not related to the index of exposure dosages. Some risk factors for CHD such as total serum cholesterol, triglycerides, beta-lipoproteins, blood pressure, obesity, and skinfold thickness were simultaneously studied. But these variables did not prove to be important in the development of angiopathy due to carbon disulfide, especially the so-called retinopathia sulfocarbonica.

Adult↗

Immunogenic activity of a ribosomal fraction obtained from Pasteurella multocida.

The cells of P. multocida strain P-1059 were destroyed with the French pressure cell; the ribosomal fraction proven to be homogeneous by analytical ultracentrifugation was obtained from the product by centrifugal fractionation, zonal electrophoresis, and Sephadex G-200 gel filtration. The ribosomal fraction exhibited intense protective antigenicity in mice and chickens, but the lipopolysaccharide (endotoxin) and the other bacterial cell fraction obtained in this experiment did not. Sodium deoxycholate treatment of the ribosomal fraction resulted in only a 13% loss in immunological activity, and ribonuclease treatment caused a 60% loss of activity.

Animals↗

Effect of extracts of the bursa of Fabricius on IgG antibody production in hormonally bursectomized chickens.

The effects of extracts of the bursa of Fabricius on the return to normal and greater than normal of antibody production in hormonally bursectomized chickens and on the switch-over of IgM antibody production to IgG antibody production was studied. Antibody production in hormonally bursectomized chickens treated with bursal extract was markedly increased as compared with bursectomized birds not given bursal extract and the IgG antibodies at three weeks was similar to that in normal immune chickens.

Animals↗

A neutrophil chemotactic factor and its inhibitor found in DNCB-induced skin inflammatory lesions.

Neutrophil chemotactic factor(s) and their inhibitors were explored in the acute inflammatory skin lesions induced by the application of 4% DNCB solution with acetone in guinea pigs. Skin biopsies were taken periodically and tissue extracts were made from the biopsy specimens. Neutrophil chemotactic activity found in such extracts reached a peak at 12 to 24 hr after the induction of the inflammation, when the lesions were found to be infiltrated predominantly with neutrophils. After 24 hr, the activity gradually diminished. Physicochemical and antigenic characterization studies on the chemotactic substance indicated that the material was most likely the cleavage product of C3. On the other hand, inhibitors against the neutrophil chemotactic factor were found in the tissue extracts which were obtained from the lesions at a later stage (48 to 96 hr after the induction of the inflammatory reaction). These inhibitors blocked not only the complement-derived chemotactic activity but also that obtained from bacterial culture filtrates. They were heat labile and showed striking heterogeneity in size on Sephadex gel filtration.

Animals↗

Polychlorinated biphenyl(s) as a promotor in experimental hepatocarcinogenesis in rats.

The effects of dietary polychlorinated biphenyls (PCBs) on hepatocarcinogenesis in female rats of Donryu strain receiving 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) were investigated. Oral administration of PCBs after administration of 3'-Me-DAB resulted in a high incidence (64%) of hepatocarcinoma. In contrast, administration of a similar amount of PCBs before, or together with 3'-Me-DAB did not induce hepatic tumors. Administration of a slightly larger amount of PCBs alone did not induce liver tumors, while administration of a slightly larger amount of 3'-Me-DAB alone caused only a low incidence (13%) of hepatocarcinoma. These results strongly suggest that PCBs exert a potent promoting action in experimental azo dye hepatocarcinogenesis.

Adenoma↗