Search PubMed⌕ Search

Biomedical subjects

M Yoshimura

Publications and source records attributed to M Yoshimura.

At least 775 records · Page 43Linked to original sources
PubMed1983

Cardiovascular and sympathetic nerve responses induced by intracerebroventricular injections of prostacyclin in rats.

Intracerebroventricular (ICV) injections of prostacyclin (PGI2) produced biphasic blood pressure responses consisting of an initial hypotensive phase followed by a sustained pressor phase in awake rats. Heart rate increased following such injections in either awake or anesthetized rats. PGI2, 1 microgram, produced biphasic responses and, 10 micrograms, purely vasodepressor responses in anesthetized rats, but abdominal sympathetic nerve firing recorded was consistently increased. Hypophysectomy did not affect the hypotensive phase of the responses. These results indicate that the initial hypotension can not be explained by centrally-induced changes in sympathetic nerve activity or vasopressin release, but may be due to peripheral effects of PGI2 leaking from the injection site.

Animals↗
PubMed1983

A clinical study of the order and speed of sensory recovery after digital replantation.

The order of sensory recovery (the first appearance of each sensory modality in the amputated digit) and the speed of sensory recovery in the amputated digit were recorded in 74 replanted digits in which both digital nerves had been severed and repaired primarily. The order of sensory recovery was measured by Frey hairs to determine pressure (30 gm) and touch (2 gm). Pain (5 gm) was measured by an algesiometer and cold (0 degree C) and warmth (50 degrees C) were measured by a thermometer (Yufu Seiki Co., Ltd.). Perspiration was measured by the bromophenol blue printing method. The mean times of the appearance of sensibility in the amputated digits were: pressure, 9.8 weeks; touch, 11.6 weeks; pain, 13.4 weeks; cold, 15.3 weeks; warmth 16.8 weeks; and perspiration, 26.9 weeks. The speed of sensory recovery was a measurement of the first appearance of sensibility in the amputated digit to the restoration of sensibility to the fingertip. The speed of sensory recovery for touch and pain was calculated by dividing the number of months required for sensory recovery by the distance from the replant level to the fingertip. The mean speed of sensory recovery for touch was 14.0 mm per month, and for pain it was 13.2 mm per month.

Adolescent↗
PubMed1983

Centrally induced cardiovascular and sympathetic responses to hydrocortisone in rats.

Central effects of hydrocortisone were investigated by injecting it intracerebroventricularly (icv) while recording blood pressure and heart rate in awake rats. Dose-dependent increases in both blood pressure and heart rate occurred following injections of hydrocortisone. Pretreatment by icv injections of the angiotensin II antagonist, [Sar1-Ile8]angiotensin II, completely abolished vasopressor responses to subsequent injections of hydrocortisone. When rats were later anesthetized with urethan to allow recording of abdominal sympathetic nerve activity, hydrocortisone produced vasopressor responses accompanied by corresponding increases in sympathetic nerve firing, which were also abolished by central pretreatment with either [Sar1-Ile8]angiotensin II or angiotensin I converting-enzyme inhibitor, captopril. These results indicate that centrally administered hydrocortisone stimulates the brain renin-angiotensin system to produce vasopressor responses by increasing sympathetic nerve firing.

Animals↗
PubMed1983

Free vascularized fibular transplant. A new method for monitoring circulation of the grafted fibula.

Free vascularized fibular grafts were used to treat seventeen patients who had extensive defects and pseudarthroses in long bones of the extremities. Of the seventeen, thirteen had been followed for from eighteen months to five years and could be evaluated. All thirteen grafts healed with no radiographic evidence of bone necrosis or resorption. During the immediate postoperative period, the patency of the anastomoses was monitored by observing the color of the skin of an island pedicle (so-called buoy) skin graft whose blood supply was in continuity with that of the fibular graft. Preoperative Doppler measurements were used to determine the most favorable location for the island pedicle graft. In the presence of defects of both bone and skin, the skin defect can be covered by using a large buoy flap. The largest flap used in this series measured fifteen square centimeters.

Adolescent↗
PubMed1983

Antihypertensive effect of nifedipine and its relationship to severity of hypertension.

The antihypertensive effect of nifedipine (Adalat), a Ca2+-antagonistic drug, was studied in patients with mild or severe hypertension. In both short- and long-term trials, nifedipine exerted a strong hypotensive effect, more pronounced in patients with severe than in cases with mild hypertension. The results of our short-term study showed a positive correlation between the maximum fall in blood pressure induced by nifedipine and pretreatment systolic blood pressure values or the total severity index score of hypertension. In our long-term trial, we also observed a positive correlation between maximum reduction of blood pressure--induced by nifedipine--and pretreatment values. However, no correlation between reduction of blood pressure and total severity index score of hypertension could be established. Our results indicate that nifedipine could be effective in the management of severe hypertension. The hypotensive action of nifedipine, at least partly due to its Ca2+ influx blocking action, suggests that etiologically hypertension may be connected with an abnormal calcium metabolism of the cardiovascular muscle cells.

Adult↗
PubMed1982

Immunological similarity of CEA with alpha 1-acid glycoprotein (orosomucoid).

We have demonstrated that 125 I-CEA (carcinoembryonic antigen) from two commercial sources (Roche and CIS RIA kit) can be precipitated by antibody to alpha 1-acid glycoprotein (AG) dose-dependently. The binding of 125 I-CEA to anti-AG can be displaced by unlabelled AG, though, there was no cross-reaction between AG and anti-CEA. The data strongly suggest that CEA has an immunological similarity to AG. The perchloric acid extract from cancerous tissue was fractionated on a Sephadex G-200 column, and the first eluted fraction (containing large amounts of CEA) was subjected to affinity chromatography using anti-AG bound to Sepharose. The bound fraction was eluted, labelled with 125 I, and then applied to a Sephadex G-200 column with carrier protein. The radioactivity was found mainly in the large molecular size eluted fraction (Fr 1). Almost all radioactivity of Fr 1 was precipitated by anti-AG and anti-CEA. This experiment also demonstrated that a large molecular weight component (Mr: 180 000) obtained from tumor was immunologically related to both CEA and AG. Based on differences in binding affinities between CEA with anti-CEA and with anti-AG we postulate that CEA may be a large molecular precursor of AG (big form of AG).

Carcinoembryonic Antigen↗
PubMed1982

Recovery of sensation in replanted digits--time of recovery and degree of two-point discrimination.

Even if good motor function returns in a replanted digit, if no useful sensation returns, the digit cannot be considered fully functional. In such cases sensory reconstruction with nerve grafts may be necessary, but it is difficult to determine the optimal time for such surgery. Therefore, we studied 37 replanted digits in which the palmar digital nerves had been severed bilaterally and anastomosed at the replantation procedure. Our findings indicate a correlation between the time at which sensation returned to the digits and the degree of two-point discrimination (2PD) that returned. In digits in which sensation returned less than four months after replantation, a 2PD of less than 15 mm returned in more than 50% of cases, but when more than four months passed before the return of sensation, a useful degree of 2PD seldom returned. We believe, therefore, that if the recovery of sensation in a replanted digit has not been satisfactory by four months after replantation, reconstructive surgery should be considered.

Adult↗
PubMed1982

Intracellular recordings from lateral horn cells fo the spinal cord in vitro.

Intracellular recording was used in studies of the preganglionic neurons of the autonomic nervous system. These were carried out on isolated segments of the cat spinal cord. It was found that the lateral horn cells have electrical membrane characteristics similar to postganglionic neurons, but many of them have a much longer afterhyperpolarization. 5-Hydroxytryptamine, noradrenaline and aspartate induce depolarizations in lateral horn cells which are characteristically associated with an increased membrane resistance. EPSPs in lateral horn cells are not cholinergic in nature, though many cells are endowed with excitatory nicotinic receptors. Some interneurons also appear to have excitatory muscarinic receptors. Glutamate can depolarize many lateral horn cells. This excitatory amine does not seem to be responsible for the production of an EPSP, since the EPSP persisted during the continued presence of glutamate in the superfusing medium. All the neurons examined in the lateral horn are susceptible to the hyperpolarizing and shunting actions of GABA and glycine. In a small group of neurons, noradrenaline caused a hyperpolarization.

Acetylcholine↗
PubMed1982

Endogenous brain angiotensin II-mediated sympathetic nerve responses are not augmented in mature spontaneously hypertensive rats.

Conjugated estrogens injected into the lateral brain ventricle in awake rats elicited behavioral excitation and vasopressor responses. Magnitude of pressor responses was greater in spontaneously hypertensive rats (SHR) than in normotensive Kyoto Wistar rats (WKY). Pressor responses in SHR were abolished by central pretreatments of either captopril or angiotensin II analog. Under urethane anesthesia, conjugated estrogens still produced greater pressor responses in SHR, but accompanying increases in sympathetic nerve firings were the same in both WKY and SHR. These results suggest that while centrally-administered estrogens may activate the brain renin-angiotensin system to increase sympathetic nerve firing and thereby elevated blood pressure, SHR have larger pressor responses only because peripheral vascular reactivity has been increased.

Angiotensin II↗
PubMed1982

The role of brain angiotensin II in the mechanism of the pressor responses to intracisternal injection of hypertonic NaCl in urethane anesthetized rats.

Intracisternal injections of hypertonic NaCl elicited the pressor responses in urethane anesthetized spontaneously hypertensive and normotensive Wistar rats. The intracisternal pretreatment of 1-Sar-8-Ile-angiotensin II, angiotensin II analog, could abolish the pressor responses to intracisternal injections of 5% NaCl in urethane anesthetized spontaneously hypertensive rats, while basal blood pressure was not affected by these pretreatment. Both intracisternal and intravenous administration of captopril, an angiotensin I converting enzyme inhibitor, did not alter the pressor effect of hypertonic NaCl in normotensive rats. Basal blood pressure was lowered by intravenous injection of captopril. The involvement of angiotensin II in the pressor mechanism of hypertonic NaCl was confirmed by the enhanced pressor responses to intracisternal injections of 5% NaCl in urethane anesthetized rats pretreated intracisternally with angiotensin II. These findings suggest that angiotensin II itself could play an important role in the pressor responses to intracisternal injections of hypertonic NaCl without involving a converting enzyme system.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1982

An assay for antibodies to thyroid plasma membrane using the isotope-labeled protein A.

An assay for detection of serum IgG binding to thyroid membrane using 125I-Protein A was examined. The test serum is incubated with purified thyroid membranes, and the IgG bound to the membrane is detected by its interaction with 125I-Protein A. Most of the bound IgG is not bound to the TSH receptor, because TSH does not induce any appreciable decrease in the binding of the IgG to thyroid membranes. Increased serum IgG binding to thyroid membrane is found in most patients with Graves' disease and Hashimoto's thyroiditis, but not in patients with thyroid cancer or simple goiter. Many sera with positive binding activity showed positive microsomal antibody. Serum IgG binding to thyroid membrane in Graves' disease correlates neither with LATS activity nor thyroglobulin antibody. This finding suggests that TSH receptor is not involved in the reaction. The assay method is useful for measuring the binding immunoglobulin for thyroid membrane that is frequently increased in autoimmune thyroid disease, and the present data provide further support to the concept that thyroid autoimmune disorders are associated with antibodies to thyroid cell surface components.

Cell Membrane↗
PubMed1982

Effect of sodium loading and depletion on cyclic nucleotides in plasma and aorta. Interaction between prostacyclin and cyclic nucleotides.

The present study evaluated the effect of sodium loading and sodium depletion on cAMP and cGMP content of rat aorta. Enhanced generation of prostacyclin (PGI2) in aorta was noticed in sodium loading and sodium-depletion. As PGI2 is potent vasoactive agent, the interaction between PGI2 generation in the aorta and cyclic nucleotide accumulation in the aorta was investigated. Sodium depletion of rats induced the elevation of both cAMP and cGMP in the aorta and of cAMP in plasma. No change in cyclic nucleotides was noticed following sodium loading. These changes in cyclic nucleotides were felt to reflect the fluctuation of vasoactive agents under various sodium metabolism conditions. These observations may indicate that PGI2 is not a major factor in the regulation of cyclic nucleotide metabolism under sodium loading and sodium depletion. The increased accumulation of cAMP and cGMP in rat aorta in sodium depletion may be due to the cumulative effects of PGI2, catecholamine and probably angiotension II which are induced by sodium depletion.

Aldosterone↗
PubMed1982

Measurement of serum thyroxine binding prealbumin in various thyroidal states by radioimmunoassay.

Serum thyroxine binding prealbumin (TBPA) levels in various thyroidal states were examined by radioimmunoassay (RIA). This technique is highly sensitive, accurate and reproducible. The normal mean (+/- 2SD) level of serum TBPA is 26.9 +/- 8.0 mg/dl (29.4 +/- 5.2 in men and 24.9 +/- 7.6 mg/dl in women). Serum TBPA levels in pregnant women were significantly lower than in normal females (P less than 0.05). Serum TBPA levels in patients with untreated hyperthyroidism were 12.9 +/- 4.0 mg/dl (mean +/- SD) and in patients with untreated hypothyroidism were 25.2 +/- 4.7 mg/dl (mean +/- SD). The mean TBPA concentrations in untreated hyperthyroidism were significantly lower than that for normal population (P less than 0.01), but untreated hypothyroidism was almost within normal range. The changes in TBPA levels in hyperthyroidism and hypothyroidism were similar to those in TBG levels. In untreated hyper- and hypothyroidism, restoration to euthyroidism by treatment was uniformly accompanied by a normalization of serum TBPA and TBG levels. A negative correlation between serum thyroid hormone binding protein (TBG and TBPA) and free thyroxine was observed in patients with hyperthyroidism. The coefficient of correlation between TBPA and free thyroxine was -0.80 (P less than 0.01) and between TBG and free thyroxine -0.58 (P less than 0.01). From these experiments it appears that not only TBG but also TBPA may play an important role in the regulation of the free thyroxine concentration in response to various thyroidal states.

Female↗
PubMed1982

Placental secretion of prolactin, ACTH and immunoreactive beta-endorphin during pregnancy.

The placental secretion of Prl, ACTH and immunoreactive (IR)-beta-endorphin were examined in early and later pregnancy with a perfusion method and by determining tissue concentrations of these hormones. Prl was secreted mainly from decidual tissue during 5-6 h long perfusions. Tissue concentrations of Prl were also significantly higher in decidual than in trophoblastic tissue. In contrast, the tissue concentrations of hCG, hPL, ACTH and IR-beta-endorphin were significantly higher in decidual than in trophoblastic tissues. In contrast, the tissue concentrations of hCG, hPL, ACTH and IR-beta-endorphin were significantly higher in trophoblastic than in decidual tissues. Production of hCG and hPL was predominantly demonstrated in trophoblastic tissues by the perfusion method but ACTH and IR-beta-endorphin were too low to be detected by perfusion.

Adrenocorticotropic Hormone↗
PubMed1982

Enhanced vascular reactivity to norepinephrine in salt-sensitive patients with hypertension.

Twenty patients with hypertension were studied under diets containing low and high salt to identify factors which might be involved in elevating blood pressure under sodium-loading. They were classified as "salt-sensitive" (SS) and "nonsalt-sensitive" (NSS) according to the presence or absence of greater than 10% increases in mean blood pressure when a low salt diet was replaced by a high salt diet. During high-sodium intake, the SS patients showed reduced urinary excretion of sodium and elevated plasma levels of aldosterone as compared with plasma renin activity. The SS patients also showed an enhanced pressor response to norepinephrine under both low-sodium and high-sodium diets. From these results, it is suggested that the sodium retention, which is probably related to nonsuppressed levels of PAC under sodium-loading, is one of the factors in elevating blood pressure in the SS patients. Moreover, the enhanced pressor response to norepinephrine seems to contribute, in part, to elevation of blood pressure in the SS patients under salt-loading.

Aged↗