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Biomedical subjects

E Hayashi

Publications and source records attributed to E Hayashi.

At least 181 records · Page 10Linked to original sources
PubMed1977

Phthalate metabolism in Pseudomonas testosteroni: accumulation of 4,5-dihydroxyphthalate by a mutant strain.

A mutant strain of Pseudomonas testosteroni blocked in phthalate catabolism converted phthalate into 4,5-dihydroxyphthalate. The latter compound was isolated, and its physical properties were determined. A stoichiometric conversion of the compound to protocatechuate was demonstrated spectrophotometrically with crude extracts of a protocatechuate 4,5-dioxygenase-deficient mutant. Therefore, phthalate is metabolized through 4,5-dihydroxyphthalate and protocatechuate, which is further degraded by protocatechuate 4,5-dioxygenase in P. testosteroni. By using several mutants blocked in phthalate catabolism, 4,5-dihydroxyphthalate decarboxylase was shown to be induced by phthalate. A simple spectrophotometric assay for the enzyme is also reported.

Carboxy-Lyases↗
PubMed1977

[Effect of surugatoxin on celiac ganglia in cats (author's transl)].

Pharmacological properties of surugatoxin (SGTX), the toxic principle from Japanese ivory mollusc (Babylonia japonica), have been studied. In the present paper, the effect of SGTX on celiac ganglia in cats was investigated by measuring blood pressure from femoral artery and regional blood flow in liver (LBF) and spleen (SBF) of anaesthetized cats. SGTX(50 nmol/kg i.v.) markedly inhibited both the hypertension and changes of LBF and SBF in response to splanchnic (preganglionic) nerve stimulation. On the other hand, it did not inhibit the changes of SBF by splenic(postganglionic) nerve stimulation. The hypertension and changes in LBF and SBF in response to DMPP(94.2 nmol/kg i.v.) were abolished by SGTX(50 nmol/kg i.v.), whereas those to McN-A-343 (94.8 nmol/kg i.v.) were not. SGTX usually enhanced the pressor response to McN-A-343. These results indicate that SGTX has a blocking effect on the nicotinic receptor in celiac ganglia as well as in superior cervical ganglia of cats and rats.

(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethy↗
PubMed1977

Comparative studies on anti-nicotinic action of hexamethonium, mecamylamine and adenosine in the guinea pig isolated ileum.

The mechanism of anti-nicotinic actions of hexamethonium, mecamylamine and adenosine was investigated in guinea pig isolated ileum. Mecamylamine shifted the dose-response curves for nicotine to the right with a gradual depression. On the other hand, hexamethonium shifted the curves to the right without a depression and adenosine made only a gradual depression, suggesting the different modes of their antinicotinic actions. The transmurally-stimulated twitch response was unaffected, partially inhibited and abolis hed by hexamethonium, mecamylamine and adenosine, respectively. These three compounds also had little effect on direct muscle response to acetylcholine and on the acetylcholinesterase activity of the ileum. From these results, it is suggested that the antagonism to the effect of nicotine shown by mecamylamine does not appear to be a simple competitive blockade of ganglionic receptors as is the case with hexamethonium and that adenosine may antagonize the effect of nicotine non-competitively. The mechanism by which mecamylamine and adenosine showed anti-nicotinic action is discussed.

Acetylcholine↗
PubMed1977

Hana Kai II: a 17-day dry saturation dive at 18.6 ATA. IV. Cardiopulmonary functions.

Impedance plethysmography was used to measure resting cardiac stroke volume (SV) and thoracic conductive volume (TCV) in four divers at intervals during a prolonged dry saturation dive (17 days at 18.6 ATA and 7 days' decompression). Resting heart rate (HR), blood pressure (BP), and pulmonary minute ventilation (VE) were measured 4 times per day for the duration of the 30-day experiment. The vital capacity (VC) and its subdivisions IC and ERV were measured by spirometry every 3 days. In nonsmokers, VC fell significantly with time (r = 0.64), while VC in smokers increased nearly 400 ml during the first week at pressure before tending to fall with time. Compared to predive, the mean ERV was increased 629 ml at pressure, while VE and respiratory rate were not changed. The increased ERV did not persist postdive and was probably the result of the increased work of breathing a dense gas (4.1 g/liters). Residual volume (RV) measured by nitrogen dilution before and after the dive increased 38% and remained significantly increased (22%) even after one year in 4 divers. It is suggested that hyperoxia (0.3 ATA PO2) combined with increased gas flow resistance caused the VC to fall and RV to increase. The major cardiovascular findings were a transient bradycardia associated with increased stroke volume leading to a significant increase in resting cardiac output associated with an increased rate of rapid ventricular filling, TCV, and BP at depth. Lowering the ambient temperature for 3 days did not re-establish the bradycardia, suggesting that hyperbaric bradycardia is not due to a subtle cold stress.

Adult↗
PubMed1976

Effect of oxygen saturation on H+ and Cl- distribution across the red cell membrane in human and ruminant blood.

Alterations of red cell pH (pHc) and distribution ratios of H+ (gammaH+) and Cl (gammaCl-) between plasma and red blood cells with oxygenation of blood were studied in human blood (audult and fetal) and ruminant blood (bovine, goat and sheep). The experiments were carried out at a plasma pH of 7.0 to 7.7 and at 37 degrees C. In human blood pHc of fully oxygenated blood was 0.035 pH lower than that of fully deoxygenated blood in all ranges of plasma pH studied. In ruminant blood, however, the differences in pHc between oxygenated and deoxygenated blood were 0.011 in ox, and 0.003 in goat and sheep, all of them not being significant. The decreases in gammaH+ accompanying oxygenation were in fairly good agreement with those in gammaCl- in human blood and amounted to about 0.05. In ruminant blood, in spite of virtually zero changes in gammaH+ with oxygenation, the decreases in gammaCl- were slightly greater than those in human blood. There might be a species difference in the mechanisms of distribution of Cl- and H+ across the red cell membrane.

Animals↗