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Biomedical subjects

K Ota

Publications and source records attributed to K Ota.

At least 541 records · Page 30Linked to original sources
PubMed1987

T cell subsets and Ia-positive cells in the sciatic nerve during the course of experimental allergic neuritis.

The changes of T cell subsets and Ia-positive cells in the sciatic nerve during the course of experimental allergic neuritis (EAN) in Lewis rats were studied using immunohistochemical techniques. OX-6+ Ia-positive cells and W3/13+ total T cells were found at the clinical onset of EAN. OX-6+ cells were more numerous than W3/13+ cells during all phases of the disease. In the acute phase, more W3/25+ helper T cells were found than OX-8+ suppressor/cytotoxic T cells in the sciatic nerve. In the recovery phase, W3/25+ cells were slightly fewer than OX-8+ cells. It is suggested that these changes in T cell subsets and Ia-positive cells are related to the self-limiting monophasic course of EAN.

Animals↗
PubMed1987

Double immunoenzymatic detection of surface phenotype of proliferating lymphocytes in situ with monoclonal antibodies against DNA polymerase alpha and lymphocyte membrane antigens.

To detect the proliferating cells in situ, a monoclonal antibody against human DNA polymerase alpha (pol alpha) was employed because this enzyme is known to be present in the nucleus of the cells in G1, S, and G2 phases. In addition, the surface phenotype of pol alpha-positive proliferating lymphocytes in diseased lymph nodes was determined by double staining consisting of immunoperoxidase and immunoalkaline phosphatase methods with various monoclonal antibodies against lymphocyte membrane antigens. In the paracortical area of lymph nodes with reactive changes, proliferating cells were 17% or less, and most of them were helper T-cells, although suppressor T-cells and B-cells also proliferate to a certain extent. In contrast, the proliferating cell population in malignant lymphomas was generally more than 40%, and it showed a single surface phenotype, indicating monoclonal proliferation. In addition, an unusual T-cell antigen phenotype of proliferating cells was observed in some cases of peripheral T-cell lymphomas. Thus, this double staining provided the authors with valuable information regarding the proportion, localization, and surface phenotype of proliferating cells, which should be useful for diagnosis of the diseases of lymphoid system.

Antibodies, Monoclonal↗
PubMed1987

A rapid bioassay for quantification of atrial natriuretic polypeptides.

A quantitative bioassay for the detection and quantification of atrial natriuretic polypeptides (ANPs) was developed in a pentobarbital-anesthetized rat. Ten percent mannitol in 0.9% saline was infused to achieve stable diuresis. The conductivity of the urine, urine flow, and blood pressure were continuously recorded. A bolus injection of synthetic alpha-human atrial natriuretic polypeptide (alpha-hANP) elicited dose-dependent increases in the urine conductivity, sodium excretion, and urine volume. Changes in the urine conductivity correlated significantly with the increase in sodium excretion. By use of changes in urine conductivity, biological ANP activity of crude rat atrial extract was determined. Atrial contents of ANP in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) were 25.5 +/- 1.2 microgram per atrium (n = 4) and 25.1 +/- 0.8 (n = 5) in euhydration. They were increased to 27.0 +/- 1.1 micrograms (n = 4) and 29.3 +/- 1.3 (n = 5, P less than 0.05), after 5-day water deprivation, respectively. This assay procedure provides a good tool for rapid and quantitative determination of ANPs.

Animals↗
PubMed1987

Responses of vasopressin and enkephalins to hemorrhage in adrenalectomized dogs.

To study responses of methionine enkephalin-like substance (MELS) and vasopressin (AVP) to hemorrhage, plasma MELS, AVP, and catecholamine levels and mean arterial blood pressure (MAP) and central venous pressure (CVP) were investigated in intact and adrenalectomized dogs (n = 34) under pentobarbital anesthesia. Plasma MELS increased significantly following a hemorrhage-induced rise in plasma epinephrine in intact dogs (n = 6). Plasma AVP rose concomitantly with a fall in CVP before MAP fell, but the subsequent fall in MAP was accompanied by a further elevation in plasma AVP concentration. In nonhemorrhaged control dogs (n = 6) these parameters did not change during the experiment. In adrenalectomized dogs (n = 6) the hemorrhage-induced increase in plasma MELS and AVP was significantly attenuated despite similar decreases in MAP as in intact dogs. In sham-operated dogs (n = 10) changes in these parameters were similar to those in intact dogs. The differences between plasma MELS in the superior vena cava and thoracic aorta did not change during hemorrhage in intact dogs (n = 6), but the differences in plasma AVP rose significantly, indicating a release of the hormone from the head. These results indicate that MELS release elicited by hemorrhage may largely arise from the adrenal gland and not the brain. Adrenalectomy attenuated AVP response to hemorrhagic hypotension.

Adrenalectomy↗
PubMed1987

Effects of centrally administered atrial natriuretic peptide on renal functions.

In order to assess the effects of centrally administered atrial natriuretic peptide (ANP) on renal water and electrolytes handling, arterial blood pressure, plasma vasopressin, renin activity, aldosterone, and ANP concentrations, synthetic alpha-human ANP (alpha-hANP) was administered intracerebroventricularly at a dose of 2.6 pmol.kg-1.min-1 for 30 min in pentobarbital-anaesthetized dogs (N = 6). In the control study (N = 6), artificial cerebrospinal fluid was infused. Intracerebroventricular administration of alpha-hANP increased significantly urine flow from 178 +/- 37 to 303 +/- 43 microliter/min (mean +/- SEM), sodium excretion from 27.3 +/- 8.9 to 54.4 +/- 10.5, mumol/min, potassium excretion from 16.1 +/- 3.7 to 24.0 +/- 5.1 mumol/min, and osmolar and negative free water clearances, accompanied by a significant rise in renal blood flow from 77.0 +/- 14.6 to 94.9 +/- 16.9 ml/min. Whereas glomerular filtration rate fell significantly, blood pressure and heart rate did not change. Plasma ANP, aldosterone, and PRA did not change significantly during the experiment, but plasma AVP were slightly but significantly decreased from 52 +/- 11 to 34 +/- 6 nmol/l. On the other hand, these parameters showed no changes in the control study, except a significant fall in glomerular filtration rate and a significant rise in PRA. Thus, it has been confirmed that ANP centrally brings about diuresis, natriuresis, and kaliuresis via some unknown mechanisms independent of the release of these hormones.

Aldosterone↗
PubMed1987

The effect of short-lasting atrial pacing on the release of atrial natriuretic peptide, vasopressin, and methionine enkephalin in man.

In order to study the effect of atrial tachycardia on the release of atrial natriuretic peptide (ANP), AVP, and methionine enkephalin (M-Enk), plasma concentrations of these peptides in the right ventricle were determined in patients with various arrhythmias (N = 10) during cardiac catheterization and incremental atrial pacing. Each pacing (100 per min, the maximum rate for 1:1 atrioventricular conduction, and 200 per min) lasted 4 to 5 min. Plasma ANP was significantly increased from 53.1 +/- 12.2 in the resting condition to 168.9 +/- 59.9 pmol/l at a pacing rate of 200 beats per min (P less than 0.05); plasma AVP tended to decrease, but not significantly, and plasma M-Enk did not change at all. Pulse pressure in the right atrium (PPRA) and mean right atrial pressure (MRAP) tended to increase during the pacing, and at the rate of 200 beats per min PPRA was significantly higher than at the rate of 100 beats per min. Mean arterial blood pressure, plasma osmolality, and plasma sodium and potassium concentrations did not change significantly. There were significant correlations between plasma ANP and PPRA, MRAP and heart rate. These results indicate that atrial pacing stimulates ANP release with a rise in right atrial pressure, but does not influence M-Enk and AVP releases.

Adult↗
PubMed1987

[The study in the relationship between serum calcium and serum parathyroid hormone (PTH) by employing the various kits of PTH assay].

In order to evaluate the influences of serum PTH assay in the various concentrations of serum calcium, we divided into three groups which serum calcium had below 8.0 mg/dl, 8.2 mg/dl to 9.8 mg/dl and above 10.0 mg/dl at random samples and assayed PTH in serum sample, using various kits of PTH assay obtained from commercial sources. Our results suggested that the measurement of serum PTH influenced by the concentration of serum calcium and therefore, should be taken an attention of serum calcium in each sample.

Calcium↗
PubMed1987

[A study of the intestinal 47Ca absorption test employing a scintillation camera].

In order to evaluate the clinical application of the calcium absorption test from the intestine, the intestinal 47Ca absorption test by using a scintillation camera was carried out in our laboratory. The results in the intestinal 47Ca absorption test using a scintillation camera showed a good correlation to the results which were estimated by using an arm counter previously reported by us. The rate of intestinal 47Ca absorption in 8 healthy volunteers (5 male, 3 female, average age: 37.6 +/- 9.5 years) was 52.0 +/- 3.8%, 74.3% in a patient with primary hyperparathyroidism 30.4% and 32.7% in two patients with idiopathic hypoparathyroidism respectively. This method is more easily handled and can be performed for only 4 days in institutes that are set up with scintillation camera without any special preparations, and it is recommended to be of clinical usefulness for the diagnosis of calcium metabolic disorders.

Adult↗
PubMed1987

[The measurement of serum human parathyroid hormone (h-PTH53-84) and effect of exercise on calcium metabolism].

This study was focussed our attention on the measurement within the upper physiological level of human serum parathyroid hormone (PTH), using kits of human PTH 53-84. This assay kit was able to detect serum PTH in sera with subtle changes of serum calcium concentrations before and after short term exercise. These serum PTH levels before and after exercise seemed to be changed within the upper physiological levels of PTH. Thus, this study suggested that the assay kit was likely to become a useful tool of the measurement of the physiological level of serum PTH in humans.

Adult↗
PubMed1987

[Effects of derivatives of Ara-C, 5-fluorouracil and nitrosourea against intracerebral implanted L1210 leukemia].

The effects of Ara-C derivatives, 5-FU derivatives and water-soluble nitrosoureas on L1210 leukemia implanted intracerebrally have been evaluated. Daily treatment with BH-AC showed a similar effect to that of Ara-C and intermittent treatment with BH-AC showed a marked effect. Daily treatment with FT-207, UFT and HCFU, 5-FU derivatives, resulted in more than 50% ILS but the effects of these compounds were inferior to those of ACNU and BH-AC. MCNU, a water-soluble nitrosourea, was effective, but less so than ACNU.

Animals↗