Search PubMed⌕ Search

Biomedical subjects

A Hara

Publications and source records attributed to A Hara.

At least 613 records · Page 34Linked to original sources
PubMed1979

Guinea pig liver aromatic aldehyde-ketone reductases identical with 17 beta-hydroxysteroid dehydrogenase isozymes.

Two NADPH-dependent aromatic aldehyde-ketone reductases purified from guinea pig liver catalyzed oxidoreduction of 17 beta-hydroxysteroids and 17-ketosteroids. One enzyme efficiently oxidized 5 beta-androstanes and reduced 17-ketosteroids of A/B cis configuration, whereas the other enzyme efficiently oxidized 5 alpha-androstanes and equally reduced both 5 alpha-and 5 beta-androstanes of 17-ketosteroids. However, aromatic aldehydes and ketones, and 3-ketosteroids were irreversibly reduced by the two enzymes. The two enzymes utilized NADP+ or NADPH as cofactor, but little activity with NAD+ or NADH was found. Phosphate ions enhanced the NAD+-dependent dehydrogenase activity and NADH-dependent reductase activity of the two enzymes, whereas the activities with NADP+ and NADPH were not affected. The ratios of the two activities of ketone reduction and 17 beta-hydroxysteroid oxidation of the two enzymes were almost constant during the purification steps after the two enzymes had been separated by DEAE-cellulose chromatography. By kinetic studies and electrophoresis and isoelectric focusing experiments it was confirmed that both of the two enzymes were responsile for the reduction aldehydes, ketones, and ketosteroids and for the oxidation of 17 beta-hydroxysteroids. These results indicate that 17 beta-hydroxysteroid dehydrogenases may play important roles in the metabolism of exogeneous aldehydes and ketones as well as steroids.

17-Hydroxysteroid Dehydrogenases↗
PubMed1979

Pathophysiological studies on hypertension induced in rats by kidney extract and salt.

The renin-angiotensin-aldosterone system, electrolyte and water balance, body fluid, and neurogenic tone and reactivity of the vasculature were studied in hypertension induced in uninephrectomized rats by repeated injection of renin-rich kidney extract and 1% saline drinking. The control rats were injected with physiological saline. Various measurements were made in conscious rats on the 10th day of the treatment. As compared with the control, plasma renin concentration and serum sodium increased significantly, while plasma aldosterone and renal excretory function did not differ. Blood volume (BV) expressed as per body weight increased significantly, but absolute BV, absolute or body weight-related plasma volume and hematocrit were not significantly different. The hypotensive effect of 1-Sar-8-Ile-angiotensin II was negligible 12 hours after the preceding injection of kidney extract. It was small but significant 1 hour after the injection. Increase in water turn-over and fractional sodium excretion occurred during the development of hypertension. Spironolactone did not significantly modify the developmental course. We observed increased depressor response to hexamethonium and increased reactivities to noradrenaline and angiotensin II (A II); these response curves relatively resembled those of spontaneously hypertensive rats. Hypertensive vascular changes were seen in the kidney and heart by histology. Thus, it was suggested that a direct vascular action of A II played a partial role in this hypertensive process while aldosterone played little role. The significance of BV increase and possible contribution of A II's other actions were discussed.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1979

Cryoactivation of inactive renin in human plasma.

The mechanism of the increase in renin activity in human plasma which had been kept -5 degrees C for 4 days (cryoactivation) was investigated. From the results of clinical studies, it is likely that the controling mechanism of inactive renin has something in common with that of active renin. The experimental data showed that the increase in renin activity of human plasma by cryoactivation was closely correlated to the increase obtained by incubation with trypsin (r = 0.88, p less than 0.001, n = 10). Soybean trypsin inhibitor, aprotinin and di-isopropylfluorophosphate (DFP) inhibited cryoactivation, indicating that the cryoactivation is due to the action of a trypsin-like serine enzyme. Trypsin which had no effect on plasma renin activity in the presence of the same amount of soybean trypsin inhibitor at 37 degrees C, activated the renin activity during cold incubation, suggesting that the dissociation of the trypsin-inhibitor complex may have taken place at a low temperature. Endogenous trypsin inhibitor is also likely to lose its affinity to endogenous trypsin-like enzyme at a low temperature.

Cold Temperature↗
PubMed1978

Comparative studies on immunochemical properties of female-specific serum protein and egg yolk proteins in rainbow trout (Salmo gairdneri).

1. Female-specific serum protein (FS) and egg yolk proteins of mature female rainbow trout (Salmo gairdneri) were studied comparatively with reference to their immunological and some physicochemical properties. 2. FS was considered to be composed of two egg proteins, E1 and E2, which were isolated from the egg yolk by gel filtration. 3. The molecular weights of FS, E1 and E2 were estimated by gel filtration to be approx 600,000, 300,000 and 35,000, respectively. 4. The analysis with sodium dodecyl sulphate electrophoresis indicated that E1 consisted of two subunits with molecular weights of 90,000 and 15,000, and E2 was estimated to be a dimer of a molecule of 15,000. 5. Male and immature female trout were injected with estradiol-17 beta, and the production of proteins with the same antigenicity with FS was demonstrated.

Animals↗
PubMed1978

Cryoactivation of plasma renin.

1. The mechanism of increased renin activity after human plasma had been kept at -5 degrees C for 4 days (cryoactivation) was investigated. 2. The increase in renin activity of human plasma by cryoactivation was closely correlated to the increase obtained by incubation with trypsin (r = 0.88, P less than 0.001, n = 10). 3. An inhibitor of thiol enzyme, N-ethylmaleimide did not inhibit cryoactivation. 4. Soyabean trypsin inhibitor and di-isopropylflurophosphate (DFP) inhibited cryoactivation, suggesting that the cryoactivation may be due to the action of a trypsin-like serine enzyme. 5. In an experiment in the rat haemorrhagic shock caused parallel and cryoactivated plasma, the renin activity being about two times higher in the latter. No significant differences were found in the concentrations of renin and renin substrate between the non-cryoactivated and cryoactivated plasma samples. 6. The results may indicate that a destruction of an inhibitor of the renin-renin substrate reaction is responsible for the increase of renin activity after exposure of rat plasma to low temperature. A trypsin-like enzyme in plasma might have destroyed the inhibitor during this procedure.

Animals↗
PubMed1977

Simultaneous recording of electroretinogram and visual evoked response. Focal stimulation under direct observation.

A system has been tested that allows simultaneous recording of the retinal response (electroretinogram [ERG]) and the occipital response (visual evoked response [VER]) with focal photic stimulation of the retina under direct observation of the fundus. A helium-neon gas laser is used as a stimulus source. The laser is chopped either by a pen motor or a rotating disc. The laser is attached to a biomicroscope through which the examiner can observe the fundus of the subject during the entire recording session. The optically clear contact lens is made with a flat surface that neutralizes refraction due to the cornea, thereby allowing fundus observation by microscope. Two metal wires mounted inside and outside of the lens serve as the electrode for the ERG. Graticules consisting of concentric circles and radial lines are projected onto the subject's fundus, providing a pattern that the examiner can use to determine the exact location to be stimulated in the fundus. With proper adjustment of stimulus and background illumination, local ERG and VER can be recorded simultaneously by stimulating the macula.

Electroretinography↗
PubMed1977

Regional lung function in pulmonary hypertension.

Utilizing 133-xenon gas and a scintillation camera, we examined the distributional relation between ventillation (V) and perfusion (Q) in patients with pulmonary hypertension (PH) comprising mitral stenosis (MS) and left to right shunt disease (shunt). In the case of MS, Q decreased at the dependent part of lung in proportion to the degree of PH, but preserved normal V and resulted in high V/Q value at this region, which was estimated to cause and physiological dead space effect on the gas exchange function. In the case of shunt disease, even with a high degree of PH, reduction of Q at the dependent lung region was not observed with normal preservation of V, thus obviating any type of the V/Q imbalance. Since the washout of xenon gas by resting tidal volume ventilation was observed to be delayed from the dependent lung region, latent ventilatory impairment in this region due to small airway closure at tidal breathing was also suspected.

Adolescent↗
PubMed1977

Effects of beta-adrenergic blocking agents on the blood pressure, plasma renin activity and hemodynamics of hypertensive patients.

Changes in blood pressure, plasma renin activity, and hemodynamic components were studied in 23 patients with essential hypertension treated with oral pindolol or propranolol. These beta-adrenergic blocking agents effectively lowered the blood pressure in the majority of the patients. Although plasma renin activity was not significantly changed, the higher was the pretreatment level, the more it tended to be decreased. Systemic vascular resistence was significantly decreased, while changes in cardiac index and circulating blood volume were variable. Pindolol showed less effect in reducing the heart rate than propranolol. The antihypertensive effect of these drugs had no correlation with the change in plasma renin activity or in any one of hemodynamic components.

Adrenergic beta-Antagonists↗
PubMed1977

Abnormality of serum lipoprotein and spleen glycosphingolipids in a case of hereditary spherocytosis.

A patient with hereditary spherocytosis gave rise to lower levels of both erythrocyte and serum cholesterols and serum lipoproteins than normal subjects. Abnormal shape of the serum lipoprotein particles was observed by electron-microscopic examination as well as the spheroidal shape of red cells. Lipids of fresh spleen tissue of the patient after splenectomy for the treatment of splenomegaly were extracted, isolated and analyzed. Particularly, different glycosphingolipids were also chemically identified and analyzed. The total lipids accounted for 10.7% of the dry tissue weight and consisted of cholesterol (32.2%), simple lipids (5.4%),phospholipids (58.3%) and glycosphingolipids (3.6%). Particularly, the glycosphingolipids were composed of monohexosyl ceramide (9.0%), lactosyl ceramide (31.2%), digalactosylglucosyl ceramide (9.2%), globoside I (27.6%) and hematoside (23.0%). It was found that the globoside I and hematoside increased remarkably in the spleen of patient with hereditary spherocytosis and that monohexosyl ceramide contained not only glucosyl ceramide, but also galactosyl ceramide at the ratio of 4:1.

Adult↗
PubMed1976

Iron-binding activity of female-specific serum proteins of rainbow trout (Salmo gairdneri) and chum salmon (Oncorhyncus keta).

The differences of serum proteins between mature male and female rainbow trout (Salmo gairdneri) and chum salmon (Oncorhyncus keta) were studied electrophoretically and immunologically. Female-specific serum proteins were seen only in females of both species, in the same region as beta-globulin on cellulose acetate membrane electrophoresis and agarose gel immunoelectrophoresis. One of the female-specific serum proteins bound radioactive iron. This protein was partially purified by precipitation by lowering the ionic strength of the serum. The purified material also showed the iron-binding property.

Animals↗
PubMed1976

Comparative studies on chemical, hemolytic and diffusion-in-gel precipitation properties of various lysosphingolipids.

Various lysosphingolipids were prepared and their chemical structures were confirmed by thin layer chromatography, infrared spectroscopy, proton magnetic resonance spectroscopy and chemical analyses of sugars, aminosugars, fatty acids and long chain bases by gas-liquid chromatography. Some hemolytic and diffusion-in-gel precipitation properties of these substances were compared with each other. Almost all of deacylated sphingolipids had approximately the same hemolytic activity. These hemolytic activities were inhibited with equal amounts of cholesterol. Aqueous solutions of digalactosylglucosylsphingosine, galactosaminyldigalactosylglucosylsphingosine and digalactosaminyldigalactosylglucosylsphingosine gave rise to non-immune precipitation lines with normal animal sera, particularly with their low density lipoproteins on agarose gel double diffusion, whereas sphingosylphosphorylcholine and neuraminylgalactosylglucosylsphingosine gave no precipitation lines at all. High concentration of lactosylsphingosine, galactosylsphingosine and glucosylsphingosine, respectively, gave rise to a slightly faint precipitation line.

Animals↗