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Biomedical subjects

M Yoshimura

Publications and source records attributed to M Yoshimura.

At least 793 records · Page 44Linked to original sources
PubMed1982

Central vasopressor responses to conjugated estrogens in rats may be mediated via a renin-angiotensin system in the brain.

Central effects of sex steroids on cardiovascular regulation and on behavior were investigated by injecting conjugated estrogens i.c.v. in conscious or anesthetized rats. Conjugated estrogens (0.1-10 micrograms) produced dose-related increases in pressure and behavioral excitation in all rats and drinking in some rats. Marked increases ii pressure and excitation with tonic convulsions resulting in death were produced by similar injections of conjugated estrogens (100 micrograms). Pretreatment with angiotensin I converting enzyme inhibitor or angiotensin II analog abolished both vasopressor responses and behavioral excitation in conscious rats. When rats were later anesthetized with urethane to allow recording of sympathetic nerve activity, 10 and 100 micrograms of conjugated estrogens produced dose-related vasopressor responses accompanied by corresponding increases in peripheral sympathetic nerve activity. Again, converting enzyme inhibitor or angiotensin II analog abolished the increases in both blood pressure and sympathetic nerve activity. By contrast, when conjugated estrogens were injected i.v. up to 2 mg/kg, neither blood pressure nor sympathetic outflow was affected. Collectively, our results suggest that conjugated estrogens infused centrally activate a renin-angiotensin system in the brain, which results in sympathetic hyperactivity leading to blood pressure elevation.

Animals↗
PubMed1982

Clinical replantation of digits and its problem.

571 replanted digits in 395 patients were critically evaluated from the point of view of the surgical technique, level of amputation, post-operative complications and the eventual functional end result. When the period of ischaemia exceeded 10 hours, the risk of failure was higher. Bone union was delayed in the digits in which the period of ischaemia was longer than 5 hours. Single thumb and multiple finger amputations were functionally most useful regardless of the level of amputation, the range of mobility or the sensory recovery. Single finger replantations resulted in poor function especially for the index and little finger. Replantation of a single finger amputation is of questionable value from the point of view of time spent both by the surgeon and the patient. Surprisingly, replantations for amputation proximal to the proximal interphalangeal joint produced much less satisfactory functional result as compared to those for amputations distal to this joint.

Adult↗
PubMed1981

Effects of viral transformation on synthesis and secretion of collagen and fibronectin-like molecules by embryonic chick chondrocytes in culture.

Monolayer cultures of chondrocytes isolated from 11-day-old chick embryo vertebral cartilage were transformed by Rous sarcoma virus, and the effects of transformation on synthesis and secretion of extracellular proteins by these cells were studied. Transformation resulted in decreased synthesis of type II collagen which did not appear to be due to underhydroxylation of collagenous protein but to a decrease in the total amount synthesized. Carboxymethyl-cellulose chromatography and polyacrylamide disc gel electrophoresis failed to demonstrate any alpha 2 chains as a result of the transformation, suggesting that conversion of type II to type I collagen did not occur. In contrast to the decrease in collagen synthesis, synthesis of a molecule with biochemical characteristics similar to fibronectin increased markedly in virally transformed cultures. Although there were no significant differences in the amount of fibronectin-like molecules in the cell layers of normal and transformed chondrocytes, a marked increase of these molecules in the culture media of the transformed cells was demonstrated. These findings were confirmed by experiments with temperature-sensitive mutants of the virus.

Animals↗
PubMed1981

In vitro differentiation of chicken embryo skin cells transformed by Rous sarcoma virus.

The epidermal cells isolated from 14-day chicken embryo shank skin epidermis were infected in vitro with Rous sarcoma virus (RSV). Within a few weeks, rapidly growing colonies of epithelial cells appeared among the sea of transformed fibroblastic cells. When isolated and subcultured, these cells were found to possess typical markers of skin epidermis. The presence of major keratin and typical epithelial cell type morphology strongly suggested that these cells were transformed epidermal cells retaining their differentiated characteristics but having the capacity to propagate in cell culture. If RSV tsNY68, an RSV mutant having a temperature lesion in the src gene, was used, similar transformed epidermal cells were obtained at 36 degrees C (permissive temperature). At the nonpermissive temperature (41 degrees C) the growth rate of these cells decreased and additional keratin species appeared. At 41 degrees C the cells were flattened and lost the refractivity in their peripheries. All the keratins which are synthesized at the nonpermissive temperature were present in normal differentiated shank skin of 19-day old chick embryo. These cells also had "cornified envelop," indicating extensive differentiation. Viral production was as efficient as transformed fibroblasts during the rapid growth phase, while it declined significantly after the cells reached confluency, exhibiting the differentiated characteristics. Since no normal epidermal cells could be cultured under our experimental conditions, these results represent examples in which the src gene is essential for propagation of differentiated cells in cell culture while it abolishes only a part of differentiated characteristics.

Animals↗
PubMed1981

Detection of HBsAg in the pancreas.

Hepatitis B surface antigen (HBsAg) has been reported to be present in other organs than the liver. 3,9 So far as our knowledge is concerned, however, any report of cases dealing with pancreatic diseased induced by hepatitis B virus (HBV) has not been described in the English and Japanese literature. We report an autopsy case with a pancreatic lesion characterized by damage of both exocrine and endocrine epithelial cells with inflammatory responses, which were immunohistochemically found to be positive for HBsAg, and electron-microscopically to possess core-like particles in the nucleus and cytoplasm.

Chronic Disease↗
PubMed1981

Plasma pituitary hormone responses to the synthetic enkephalin analog (FK 33-824) in normal subjects and patients with pituitary diseases.

D-Ala, Mephe, Met, enkephalin (Sandoz FK 33-824) is a stable long acting analog of methionine-enkephalin. FK 33-824 (0.5 or 1.0 mg), elicited plasma GH and PRL responses in normal subjects. In 23 patients with pituitary dwarfism, the response of plasma GH was markedly impaired, while PRL responded to a variable degree. In patients with acromegaly, there was little or no increase in GH and PRL after FK 33-824. Plasma GH increased to a variable degree after FK 33-824 in patients with hyperprolactinemia, with little change in plasma PRL. FK 33-824 decreased plasma cortisol in normal subjects and patients with pituitary disease. These results show that patients with acromegaly and hyperprolactinemia due to pituitary adenomas and patients with pituitary dwarfism do not respond well to FK 33-824, presumably because of hypothalamic or pituitary derangement.

Acromegaly↗
PubMed1981

Sympathetic and pressor hyperresponsiveness to intracisternal injections of hypertonic NaCl in DOCA hypertensive rats.

Blood pressure and sympathetic nerve activity were recorded before and after intracisternal injections of hypertonic NaCl solution in urethane anesthetized normotensive and deoxycorticosterone acetate (DOCA) hypertensive rats. Dose dependent pressor effects were recorded by intracisternal injections using normotensive Wistar rats. And the early phase of responses which were significantly depressed by blocking alpha-adrenergic receptors with phentolamine, accompanied by increased frequency of sympathetic nerve firing. Pressor responses and acceleration of the rate of sympathetic nerve firing produced by intracisternal injections of hypertonic NaCl were appreciably larger in DOCA hypertensives whose basal sympathetic nerve activity was elevated significantly than in normotensive rats. Pressor responses to intravenous injection of norepinephrine were also augmented, but responses to intracisternal injection were augmented more than those to norepinephrine injection. These findings suggest that sodium sensitive site which connects to pressor systems supposedly located around lower brain stem could be hypersensitive and eventually contribute to peripheral sympathetic hyperactivity in DOCA hypertension.

Animals↗
PubMed1981

Clinical study on increased serum thyroxine-binding globulin in cancerous state.

Serum thyroxine-binding globulin (TBG) in 169 patients with various cancers was determined by radioimmunoassay (RIA). Eleven patients showed a high serum TBG level (greater than 35 micrograms/ml). Two of them had been treated with estrogen for prostate cancer. One patient had high serum TBG with serum hepatitis. Another 8 cases had normal liver function and also normal levels serum estrogen. Thus, about 4.7% (8/169) of the cancer patients had high serum TBG and mild hyperthyroxinemia caused by unknown mechanisms. The high TBG level in these patients continued until just before death, or in some cases decreased to normal after removal of cancer tumors by operation. Cancer is occasionally associated with an increase in serum TBG. Although the mechanism is not clear, the increased TBG in the cancerous state in interesting and has significance as a tumor marker.

Adult↗
PubMed1981

Light microscopic localization of hepatitis B virus antigens in the human pancreas. Possibility of multiplication of hepatitis B virus in the human pancreas.

Hepatitis B virus has been considered to be strictly organotropic and to infect and multiply only the hepatocytes of humans and chimpanzees. The localization of hepatitis B surface antigen in extrahepatic tissues has been regarded as due to deposition or phagocytosis of hepatitis B surface antigen circulating in the blood. In the present study, however, we demonstrated hepatitis B virus antigens in the pancreases of autopsied subjects with hepatitis B surface antigenemia by Shikata's orcein stain, and immunoperoxidase, immunofluorescent studies; hepatitis B surface antigen and hepatitis B virus core antigen were localized within the cytoplasm of pancreatic acinar cells in 18 and 6 cases, respectively, out of 30 cases studied. In contrast, 25 autopsy cases with no hepatitis B surface antigenemia failed to stain hepatitis B surface antigen or hepatitis B core antigen in the pancreas and liver. Therefore, it may be reasonable to assume that hepatitis B virus can infect and replicate in the human pancreatic acinar cells; however no convincing hepatitis B virus-associated ultrastructures were detected in the present study. Although there were some cases demonstrating chronic inflammatory reaction or fatty necrosis, or both, in the pancreas with hepatitis B virus antigens, the causal relationship between these pathologic changes and hepatitis B virus infection awaits further clarification.

Adult↗