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Biomedical subjects

Y Murayama

Publications and source records attributed to Y Murayama.

At least 325 records · Page 18Linked to original sources

Studies on the QRS wave of the spatial magnitude electrocardiogram in ventricular septal defect.

The QRS wave of the spatial magnitude electrocardiogram (ECG) was investigated in 86 cases of the ventricular septal defect (VSD). The relationship between the amplitude and the time interval of QRS wave of the spatial magnitude ECG and the various hemodynamic parameters obtained by the right heart catheterization and the defect area ascertained during the operations were evaluated.

Adolescent↗

Natriuresis of fasting in intact and adrenalectomized rats.

Experiments were carried out in an attempt to elucidate the mechanism of fasting-induced natriuresis in conscious rats. Female animals were given low sodium diet and saline in a fixed concentration for at least three days, and deprived of food thereafter. The sodium balance significantly shifted to negative independently of potassium supply in intact rats. Such was also observed in the dexamethasone-replaced, adrenalectomized rats and was not affected by further administration of aldosterone. In addition, the diuretic effect of insulin in fasted intact rats was not evident in the fed diabetic rats in which diabetes had been induced by streptozotocin. Such findings suggested participation of factors other than insulin. The natriuresis of fasting in intact rats appears to involve two factors, one of which is independent of the sodium intake level. Dependence on the sodium intake level may be derived from alteration of the solute diuresis-like effect of drinking saline w hen animals are fasted. These results suggest that neither aldosterone nor insulin is a major causal factor involved in fasting-induced natriuresis.

Adrenalectomy↗

[Studies on the normal polarcardiogram using the posteroanterior axis as the polar axis (author's transl)].

Polarcardiograms using the posteroanterior axis as the polar axis were recorded in 112 cases of the clinically healthy subjects. QRS wave with small notch or slur both in front and behind of the main triangular configuration with narrow base were most frequently observed in the frontal magnitude ECG. T wave showed simple monophasic upright wave with the mildly sloping ascending limb and the relatively rapidly sloping descending limb. The magnitude of the maximum QRS vector and the maximum QRS vector time in frontal plane were very similar with those of the spatial QRS vector. The quantitative values obtained by the measurement of the polarcardiograms agreed well with those obtained by the vectorcardiograms reported by the various authors. Polarcardiography made possible not only to know the polar coordinates of the cardiac vector at any instant very easily, but also to express the time-related curve of the polar coordinates, which vary as a function of time, in easily understandable analogue pattern. QRS and T waves of the magnitude, the alpha-longitude and P-A latitude ECG in the normal subjects were classified into the several definite patterns.

Adult↗

Serum globulin assay of estrogen-binding ability during endocrine treatment of postmenopausal advanced breast cancer.

Estrogen-binding ability of sex hormone binding globulin (SHBG) was assayed in sera of 18 postmenopausal patients with advanced breast cancer during the treatment of diethylstilbestrol by agar gel electrophoresis at low temperature. In eight cases showing high level of SHBG, seven cases (88 per cent) responded to the estrogen therapy. On the contrary, only one case (13 per cent) responded out of eight patients with low levels of SHBG. This result may indicate that the level of estrogen binding ability of SHBG (SEBA) is a useful tool in predicting response to estrogen therapy for breast cancer.

Adult↗

[Effects of fasting on the renal function of rats: Clearance experiments and Henle's loop microperfusion].

Results of a previous experiment indicated that osmotic pressure and sodium concentration in distal tubular fluid of the nephron constantly microperfused were increased during natriuresis of fasting rats. The present experiments were performed in order to clarify whether or not water reabsorption and urea movement in Henle's loop, which may modify osmotic pressure and sodium concentration in distal fluid, change in the fasting rat kidney. Non-fasting, 18 approximately 24 hours and 4 approximately 5 days-fasting rats were used. After surgical procedures, the animal was infused with 2% saline at 33.3 mul/min. The loop of Henle was perfused with 1% saline containing 0.05% lissamine green, 3H-inulin and 14C-urea at 29.1 nl/min. In the fasting groups, urinary flow and sodium excretion were increased, whereas urea excretion was depressed and inulin clearance showed a tendency to decrease. Tubular fluid to plasma ratio of osmotic pressure in the distal tubule was elevated without change of water reabsorption. From present and previous results, the increases of osmotic pressure and sodium concentration in distal tubular fluid of fasted rat kidney cannot be explained from an increase of water reabsorption in the Henle's loop. Consequently, natriuresis with fasting may contribute partially to an inhibition of sodium reabsorption in Henle's loops, possibly in the thick ascending limbs. Recovery of C-urea perfused into Henle's loops of fasted rats increased.

Animals↗

Effect of dextranase on the extracellular polysaccharide synthesis of Streptococcus mutans; chemical and scanning electron microscopy studies.

A dextranase preparation (AD17) partially purified from a culture liquor of Spicaria violacea strain IFO 6120 significantly inhibited the formation of artifcial dental plaque on a steel wire or on an extracted tooth surface. Changes in the surface morphology of Streptococcus mutans cells due to AD17 action were studied using scanning electron microscopy. S. mutans cells grown in 5% sucrose-containing broth were coated with sticky amorphous capsule-like material, whereas cells grown in sucrose in the presence of AD17 or in glucose instead of sucrose did not synthesize such capsular material. AK17 degraded commercially available dextrans of molecular weight 7 X 1(04) and 2 X 10(6) to liberate glucose and various oligosaccharides, including isomaltose. On the other hand, AD17 hydrolyzed the extracellular polysaccharides (mainly glucan in nature) of some strains of S. mutans to a limited degree. Only 15 to 36% of the total polysaccharides were hydrolyzed by AD1M with little release of isomaltose. Prolonged incubation of the polysaccharides from S. mutans with AD17 did not release additional reducing sugars, which indicates that AD17 did not contain alpha-1,3-glucanase activity. These results suggest that glucosidic linkages which are susceptible to AD17 may play an important role in the adherence of S. mutans cells to smooth surfaces.

Dental Plaque↗