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Biomedical subjects

Y Hashimoto

Publications and source records attributed to Y Hashimoto.

At least 1,657 records · Page 92Linked to original sources

Dietary control of the chain elongation of palmityl-CoA in rat liver microsomes.

The rate of chain elongation of palmityl-CoA to stearyl-CoA in rat liver microsomes was studied in connection with the nutritional status of the rats. The microsomal chain elongation activity, which had been decreased by starvation for 48 hr, was rapidly increased to a high level on refeeding. The apparent Km value for malonyl-CoA in both normal and refed rats was the same, 1.2 X 10(4)M. Both cycloheximide and actinomycin D prevented the induction of microsomal chain elongation activity which was associated with refeeding. In addition, the activity of acyl-CoA hydrolase and the rates of esterification of acyl-CoA into phospholipids and neutral lipids in microsomes were not changed by the dietary alteration. These results support the conclusion that changes of the activity of microsomal chain elongation of palmityl-CoA in various nutritional status result from a rapid synthesis of new enzyme(s).

Animals↗

Factors involved in beta-lactam antibiotic resistance in Pseudomonas aeruginosa.

A temperature-sensitive mutant, strain SS, which is assumed to be devoid of beta-lactamase activity and deficient in a permeability barrier to antibiotics, was isolated from a beta-lactamase-less mutant, strain L-2, derived from Pseudomonas aeruginosa IFO 3080. By comparing the beta-lactam antibiotic susceptibility between strains IFO 3080, L-2, and SS, the involvement of both beta-lactamase and a permeability barrier in determining the beta-lactam antibiotic resistance was estimated.

Anti-Bacterial Agents↗

Inhibition of Fc-rosette formation by synovial fluids from patients with rheumatoid arthritis.

Human red cells sensitized with one of the Rh antisera (Ripley) form rosettes (Fc-rosette) with human B lymphocytes and the rosettes are well inhibited by aggregated human IgG. As synovial fluids from patients with rheumatoid arthritis are usually hypocomplementaemic and frequently contain immune complexes, they were used for the inhibition of Fc-rosette formations in this study. The Fc-rosette inhibitory rates were inversely correlated with the levels of CH50 and C4 in the synovial fluids. Fractionation studies of the synovial fluids by ultracentrifugation and Sephadex G200 gel filtration indicated that main inhibitory activities were present in macromolecular fractions. Reduction and alkylation of the synovial fluids resulted in marked reductions of inhibitory activities. The tested synovial fluids did not contain anti-HLA activity as assessed by the microcytotoxicity test. The Fc-rosette inhibitory rates were not correlated with the levels of C3 and immunoglobulins, nor with the activity of rheumatoid factors in the synovial fluids. These results indicate that the Fc-rosette formations are inhibited by the immune complexes contained in the synovial fluids and it was confirmed that the Fc-rosette inhibition test is a simple and sensitive method for the detection of circulating immune complexes.

Arthritis, Rheumatoid↗

Rise of plasma corticosterone concentrations in rats immediately before and after birth and in fetal rats after the ligation of maternal uterine blood vessels or of the umbilical cord.

Just before normal vaginal delivery the plasma corticosterone concentration (PCC) in fetal rats increased markedly compared with that on day 22 of gestation. The PCC was elevated 2 h after birth and then declined until 12 h after birth, when it approached the level found on day 22 of gestation. Similarly, in premature newborn rats obtained by cesarean delivery on days 21 and 22 of gestation, the PCC increased 2 to 4 h after delivery and then declined. The PCC in 22-day-old fetal rats, 30 min after ligation of the maternal blood vessels running along a uterine horn, rose markedly compared with that in fetuses in the contralateral intact horn. A similar increase in PCC was not observed in either decapitated or encephalectomized fetuses, but observed in fetuses whose umbilical cords were ligated. The rise in fetal PCC after ligation of uterine blood vessels and of umbilical cords was considerably higher than that observed after various stresses reported by other investigators and also higher than that found 60 min after maternal adrenalectomy. The rise in PCC just before and just after birth and after the ligation should not be considered as the result of stress, parturition or ligation, but may be a result of the response to other factors.

Animals↗

Autoregulation of renal blood flow during ether, halothane and methoxyflurane anesthesia in dogs.

The effects of ether, halothane and methoxyflurane (0.5-1.5 MAC) on renal blood flow and its autoregulation were studied in 24 dogs. The left renal artery was perfused with the animals' own blood by a constant pressure perfusion system. The perfusion pressure ranged from 60 to 200 mmHg. Renal blood flow at the perfusion pressure of 100 mmHg was changed neither by ether nor by halothane, while it was decreased dose-dependently by methoxyflurane. At equipotent anesthetic concentrations the autoregulation of renal blood flow was only slightly impaired by ether, but significantly by halothane and methoxyflurane. Adenosine (100 mug/min) or calcium chloride (10 mg/min) which was infused directly into the renal artery resulted in a restoration of autoregulation impaired by MAC-1 of each anesthetic when perfusion pressure was raised stepwise from 100 to 200 mmHg, but no restoration was observed at low perfusion pressure below 100 mmHg. The results indicate that methoxyflurane exerts a direct constrictive effect on the renal vasculature. Adenosine and calcium may play a significant role on the response of the renal vasculature to raised perfusion pressure.

Adenosine↗

Effect of plasma-cholinesterase preparation on the phase II block of succinylcholine chloride in man.

The effect of enriched human plasma-cholinesterase preparation on the phase II block of succinylcholine chloride was studied in man during anesthesia and surgery. Intravenous administration of 8 esterase units/kg of plasma-cholinesterase did not show any discernible effect on the phase II block of succinylcholine chloride, while edorphonium 10 mg clearly antagonized the block. The finding of the present study suggests that the preparation may be ineffective for patients with a prolonged apnea following the administration of succinylcholine chloride.

Adult↗