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Biomedical subjects

Y Terayama

Publications and source records attributed to Y Terayama.

At least 91 records · Page 5Linked to original sources
PubMed1984

[Effects of continuous pure tone stimulation on blood pressure, plasma norepinephrine and urinary norepinephrine concentration in stroke-prone spontaneously hypertensive rats].

The present study was undertaken to elucidate the effect of pure tone stimulation on sympathetic nerve activity in stroke-prone spontaneously hypertensive rats (SHRSP). SHRSP were exposed to a pure tone stimulation of 4 KHz at 60 dB SPL tone burst which was interrupted at a frequency of one second and continued for one hour a day for either one 10 day course period or two 10 day course periods. Over a period of 10 days, Group A received one hour-long stimulation daily. Group B received the same type of stimulation for two separate 10 day course periods and Group C did not receive any tone stimulation. Group A and Group C did not show any significant changes in blood pressure, heart rate or body weight. However, an increase in urinary norepinephrine (NE) (p less than 0.02) which returned to pretreatment levels after tone stimulation was observed in Group A. Group B showed a significant increase in blood pressure as compared with Group A (p less than 0.02): the systolic blood pressure of Group B was 233.2 +/- 36.1 mmHg; the systolic blood pressure of the sex-age matched Group A was 193.0 +/- 25.7 mmHg. Group B displayed an increase in plasma NE concentration as compared with Group A (p less than 0.05). These findings demonstrated that the summation of two 10 day course pure tone stimulations produced a larger increase in blood pressure and plasma NE concentration than one 10 day course stimulation. These increase in blood pressure and plasma NE concentration occurred via an increase in sympathetic nerve activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1983

Photochemistry of two rhodopsinlike pigments in bacteriorhodopsin-free mutant of Halobacterium halobium.

Two photocycles due to two different pigments were found in membrane vesicles of a bacteriorhodopsin-free mutant of Halobacterium halobium. A pigment absorbing approximately 590 nm halorhodopsin (HR) underwent a faster photocycle with a phototransient at approximately 490 nm (half-time of decay, tau 1/2 = 10 ms). Another third rhodopsinlike pigment (TR) absorbing approximately 580 nm underwent a slower photocycle accompanying a phototransient absorbing below 410 nm (tau 1/2 = 0.8s). The photocycles were measured under various conditions of temperature, NaCl concentration, pH, and in the presence of cholate. All results obtained support the notion that the two photocycles are independent of each other, and the fast or the slow cycle can be abolished after these treatments. At alkaline pH, the wavelength of maximum absorbance of both pigments shifted to blue, but the magnitude of the shift of the pigment undergoing the slow photocycle was much greater than the other. The ratio of the content of the two pigments varies among bacteriorhodopsin-free mutants.

Bacteriorhodopsins↗
PubMed1982

Kinetics of pretransition in multilamellar dimyristoylphosphatidylcholine vesicle. X-ray diffraction study.

The time course of transformation between P' beta phase ad L' beta phase in multilamellar dimyristoylphosphatidylcholine vesicle containing 50% water was followed by small-angle X-ray diffraction. The transformation of P' beta leads to L' beta was 90% complete at 7 min after the temperature jump, although imperfections remained for a long time. Transformation in the opposite direction was fast as compared with P' beta leads to L' beta.

Dimyristoylphosphatidylcholine↗
PubMed1980

[Corticoids secretion in primary aldosteronism. I. Diurnal variation and the effect of dexamethasone (author's transl)].

For the purpose of studying the metabolism of adrenocortical steroids in primary aldosteronism, diurnal variation and the effect of dexamethasone were examined in four patients. The circadian rhythm of cortisol was observed in plasma aldosterone and corticosterone in all cases in the preoperative state. With regards to plasma progesterone, 17 alpha-hydroxyprogesterone and dehydroepiandrosterone-sulfate, however, no demonstrable change was noted. Dexamethasone was administered to two subjects for 10 days before the operation. As a result, the urinary aldosterone of one subject decreased on the 5th day after the administration but was restored to its original value on the 10th day, while the urinary aldosterone of the other subject did not decrease at all. On the first day after the operation, the value of plasma cortisol was elevated, losing its circadian rhythm. On the 7th day after the operation, the normal circadian rhythm was observed again in plasma cortisol. Plasma aldosterone was reduced to the normal range without any demonstrable changes on the first and 7th days after the operation. On the 30th day after the operation, a slight cortisol-like circadian rhythm was observed. Plasma levels of progesterone, corticosterone, 17 alpha-hydroxyprogesterone and dehydroepiandrosterone-sulfate were almost within the normal range throughout the pre- and post-operative periods. Although plasma progesterone was within the normal range, it tended to be lower in the postoperative state than in the preoperative state.

Adrenal Cortex Hormones↗
PubMed1980

[Corticoid secretion in primary aldosteronism. II. The renin releasing test and the angiotensin II analog infusion test (author's transl)].

To study the secretion of adrenocortical steroids, the renin releasing test and the angiotensin II analog (1-Sar, 8-Ala-Angiotensin II) infusion test was performed on four subjects with primary aldosteronism. The plasma renin activities of these subjects in the preoperative state were rather low, without any response to the renin releasing test. Plasma aldosterone was, however, significantly high and showed a tendency to declineits value when the subject was in an upright position. In the preoperative state, all the subjects lacked any alterations in plasma renin activity throughout the angiotensin II analog infusion test. Though slight elevations were observed in the blood pressure of three subjects, there was no demonstrable change in plasma aldosterone. In the other subject, though blood pressure did not change, plasma aldosterone exhibited a remarkable rise as did progesterone, 11-deoxycorticosterone and corticosterone. From these data, it was suggested that in the latter subject the aldosterone secretion was sensitive to angiotensin in comparison with ACTH. Three weeks after the operation, it was observed that plasma aldosterone response decreased, while the response of plasma renin activity to the renin releasing test was normal. This is considered to be due to the diminished sensitivity of the glomerulosa of the nonadenomatous adrenal gland to angiotensin. The levels of 17 alpha-hydroxyprogesterone, 11-deoxycorticosterone and corticosterone were almost within the normal range in the pre- and postoperative state. The levels of plasma progesterone and 11-deoxycorticosterone, however, tended to be lower in the postoperative state compared with the preoperative state.

Adrenal Cortex Hormones↗
PubMed1980

Electron microscope study of bone lesion in cholesteatoma otitis.

Biopsy specimens were obtained at ear surgery of patients with cholesteatoma otitis and were studied by electron microscopy. The osseous tissue decalcified in EDTA demonstrated degradation of collagen matrix as well as extensive degeneration of bone cells. The surface of the eroded bone was found to be in direct contact with the subepithelial connective tissue or the granulation, but not with the keratinizing squamous epithelium of matrix. These results indicate that the bone destruction by cholesteatoma is of non-osteoclastic type and lend support to the view that the keratinizing squamous epithelium do not participate in bone destruction. One the ultrastructural basis, the inflammatory process in the soft tissue adjacent to bone and extensive degeneration of bone cells are considered as cardinal factors for bone destruction in this disease.

Bone Resorption↗