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Biomedical subjects

H Nishimura

Publications and source records attributed to H Nishimura.

At least 685 records · Page 38Linked to original sources
PubMed1987

Effects of hypothalamic stimulation on activity of dorsomedial medulla neurons that respond to subdiaphragmatic vagal stimulation.

1. Effects of hypothalamic stimulation on activity of dorsomedial medulla neurons that responded to subdiaphragmatic vagal stimulation were investigated in urethan-anesthetized rats. 2. Extracellular recordings were made from 231 neurons in the nucleus of the tractus solitarius (NTS) that fired repetitively in response to single-pulse subdiaphragmatic vagal stimulation and from 320 neurons in the dorsal motor nucleus of the vagal nerve (DMV) that responded antidromically to subdiaphragmatic vagal stimulation. The mean latencies of responses to subdiaphragmatic vagal stimulation were 90.3 +/- 17.1 ms (mean +/- SD) for NTS neurons, and 90.8 +/- 11.2 ms for DMV neurons. This indicated that both afferent and efferent subdiaphragmatic vagal fibers were thin and unmyelinated and had a conduction velocity of approximately 1 m/s. 3. In extracellular recordings from 320 DMV neurons, marked inhibition preceded the antidromic response and subdiaphragmatic vagal stimulation evoked orthodromic spikes in only a few neurons. 4. Intracellular recordings from 66 DMV neurons revealed inhibitory postsynaptic potentials (IPSPs) before the antidromic responses. These IPSPs suppressed spontaneous firing and prevented excitatory postsynaptic potentials (EPSPs) from generating action potentials. 5. Stimulation in all hypothalamic loci studied, the ventromedial hypothalamic nucleus (VMH), the lateral hypothalamic area (LHA), and the paraventricular nucleus (PVN), induced responses with similar characteristics of excitation alone or excitation followed by inhibition in most NTS and DMV neurons. 6. No reciprocal effect of VMH and LHA stimulation was observed on NTS and DMV neurons. 7. Intracellular recordings from DMV neurons revealed monosynaptic EPSPs in response to stimulation of the VMH, the LHA, and the PVN. 8. PVN stimulation evoked significantly more responses in NTS and DMV neurons than VMH stimulation and more responses in DMV neurons than LHA stimulation. This suggests a difference in the number of connections between each hypothalamic site and the dorsomedial medulla. 9. The same dorsomedial medulla neurons were tested with VMH and LHA stimulation. The respective mean latencies of the antidromic and the orthodromic NTS neuron responses were 37.3 +/- 3.2 and 39.6 +/- 12.9 ms for VMH stimulation and 29.8 +/- 5.3 and 31.8 +/- 8.7 ms for LHA stimulation. The mean latencies of the orthodromic DMV neuron responses were 39.4 +/- 8.3 ms for VMH stimulation and 31.1 +/- 5.2 ms for LHA stimulation. The estimated conduction velocity from the VMH to the dorsomedial medulla was approximately 0.25 m/s and from the LHA it was approximately 0.33 m/s, which was significantly faster.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed1987

T cell gamma chain gene rearrangement without T cell receptor beta chain gene rearrangement in two cases of non-Hodgkin's lymphoma.

We report two patients with non-Hodgkin's lymphoma whose neoplastic cells had rearranged T cell gamma chain (T gamma) genes, and had the germ line DNA of T cell receptor beta chain (T beta) and immunoglobulin genes. Surface marker analysis of the neoplastic cells revealed that leukemic cells from one patient were derived from common thymocytes, while in the other patient the clonality and cell lineage could not be identified, probably due to the low percentage of neoplastic cells in the specimen. No phenotypic changes were observed after cultivation with phorbol myristate acetate, except for induction of Tac antigens on cells of one patient. Leukemic cells with only the T gamma gene rearrangement are thought to be precursor T cells that differentiate into mature T cells following T beta gene rearrangement. This suggests that such T cells with only the T gamma gene rearrangement exist among common thymocytes.

Aged↗
PubMed1987

Treatment of hemifacial spasm with transcutaneous electrical stimulation.

A transcutaneous electrical stimulation method was used to treat hemifacial spasms. This treatment was applied concomitantly with drug therapy to 21 patients, and was found effective in 17 patients (81%). Electrotherapy is considered to be useful in patients with mild spasms and in those with severe spasms for whom surgical treatment is not possible.

Adult↗
PubMed1987

Effects of captopril on cardiorenal hemodynamics in patients with severe chronic congestive heart failure.

The effects of captopril on cardiorenal function were studied in patients with chronic congestive heart failure. A single oral dose of captopril in 16 patients significantly increased cardiac indices and decreased total systemic vascular resistance. These changes were greater in subjects with higher baseline plasma renin activity (PRA). The increase in PRA and decrease in plasma aldosterone were also greater in this group. During 7 days of captopril therapy, renal plasma flow distinctly increased in 10 patients in whom renal function was followed. The increase in renal blood flow was greater in subjects with higher PRA. Simultaneous infusion of aprotinin in eight of these subjects did not affect the captopril-induced increase in renal plasma flow: these responses were the same in both PRA subgroups. The results suggest that captopril reduces total systemic vascular resistance in patients with chronic congestive heart failure through the inhibition of the renin-angiotensin system and the preferential renal vasodilating effect of captopril seems exclusively to be the sole result of this inhibition, with the kallikrein-kinin system or kinin-mediated prostaglandins not playing a major role.

Blood Pressure↗
PubMed1987

Effects of captopril on peripheral hemodynamics in severe congestive heart failure.

The effects of captopril on the forearm hemodynamics in patients with severe congestive heart failure were studied, using strain-gauge plethysmography. To determine whether prostaglandins are involved in the captopril actions, indomethacin, an inhibitor of prostaglandin synthesis, was administered. In 8 patients, captopril (25 mg) decreased mean blood pressure (P less than 0.01) and venous pressure (P less than 0.05); forearm blood flow (P less than 0.05) and maximum venous volume (P less than 0.05) were increased; forearm vascular resistance (P less than 0.05) and forearm venous tone (P less than 0.05) were decreased. Venous distensibility was improved with captopril (P less than 0.05). All the hemodynamic changes were attenuated by indomethacin (50 mg). Captopril increased circulating bradykinin (P less than 0.05), prostaglandin E2 (P less than 0.05) and 6-keto-prostaglandin F1 alpha (P less than 0.05). Indomethacin did not affect bradykinin level but blocked the increase in prostaglandins. These data suggest that captopril dilates both arterial and venous vessels not only by blocking the renin-angiotensin system but by increasing local or circulating vasodilator prostaglandins.

Blood Pressure↗
PubMed1987

Krukenberg tumors of the ovary: a clinicopathologic analysis of 112 cases.

The records from 1965 to 1985 in the Department of Obstetrics and Gynecology Kurume University Hospital were reviewed. In this period, 112 cases were fulfilled the criteria of Krukenberg tumor and they were carefully screened to clinical history, physical findings, operative findings, and histologic character of the lesion. The incidence of Krukenberg tumors in all ovarian cancer was 17.8%. The average age was 45.4 years with ranged from 23 to 71. As expected from this age distribution, 73 patients (65%) were 50 years of age or younger. A primary carcinoma of the stomach was found in 78 (69.6%) of 112 patients. In three cases, the Krukenberg tumors were associated with a recent pregnancy. Two cases were associated with ovarian dermoid cyst. Microscopically, both ovaries were involved in all cases that could be evaluated for bilaterality. The relation between age distribution and histological characteristics was examined. Signet-ring type carcinomas were observed frequently in young women and gland-formation type carcinomas in older women. Stromal hyperplasia of the tumors were remarkably common in younger women. In the patients with a recent pregnancy, the abdominal mass developed rapidly after delivery. In addition, estrogen receptors were present in all experimented cases. The above results suggested that estrogen influences tumor development and the histological character many of Krukenberg tumor.

Adult↗
PubMed1987

[Direct anti-tumor effect of recombinant human IFN-gamma evaluated in ovarian pseudomyxoma peritoneally transplanted into nude mice].

Different doses of recombinant human interferon gamma (IFN-gamma) between 1 X 10(6) and 2 X 10(7) U/kg were administered to nude mice for 21 days continuously. As a result, an anti-tumor effect was noted in comparison with a control group, although there was no significant difference between groups at each dose level. Serum CEA value was found to decrease in the groups as follows: 1 X 10(6) U/kg, 71.5 +/- 10 ng/ml; 3 X 10(6) U/kg, 90.6 +/- 4 ng/ml; 8 X 10(6) U/kg, 56.5 +/- 0.7 ng/ml; 2 X 10(7) U/kg, 47.4 +/- 12 ng/ml. Generally, the level was found to decrease in groups with high-dose administration. There was no difference in histological effect between groups at each dose level, and also no strong anti-tumor effect like that produced with other anti-cancer agents was noted with regard to histological change. It was revealed that recombinant human IFN-gamma was effective for suppression of tumor proliferation in human ovarian tumor, although its histological effect was less effective than that of anti-cancer agents such as Adriamycin and Cis-DDP.

Animals↗
PubMed1987

Genotypic analysis of lymph node cells from patients with phenotypically undetermined cell lymphoma.

Rearrangements of immunoglobulin (Ig) heavy chain (JH) and T cell receptor beta chain (T beta) genes of lymph node cells from 28 patients with malignant lymphoma were studied. Fourteen of 28 patients were diagnosed as undetermined cell lymphomas, since a marked predominance of cells expressing a single light chain of Ig or T cell associated antigens was not demonstrated by phenotypic analysis. Of these patients, JH gene rearrangements were observed in 8 patients, whereas T beta gene rearrangements were detected in 9 patients. Although bigenotypes were seen and cell lineage was not determined in three cases, these results indicate that demonstration of Ig and T beta gene rearrangements is a powerful tool to determine cell lineage and clonality of lymphoma cells that do not express definitive surface phenotypes. Interestingly, 12 of 14 lymphoma cells whose lineage had been determined by phenotypic analysis showed rearrangements of two alleles; however, only single allelic gene rearrangement was observed in 11 of 14 lymph node cells from phenotypically undetermined cell lymphoma.

Genotype↗
PubMed1987

[Stressor controllability and brain noradrenaline turnover in rats].

A series of experiments examined the effects of a purely psychological factor in a stressful situation (i.e., the ability to manage a stressor or inability to do so) on noradrenergic metabolism in regional rat brains. In Experiment 1, uncontrollable rats which could not escape and avoid electric shock developed more gastric ulceration than did controllable rats which had exactly the same shock but could exert control over the shock. In Experiment 2, the uncontrollable rats displayed sustained increases in noradrenaline (NA) turnover in various brain regions regardless of stress durations. After the controllable rats had firmly mastered the coping response, excess NA utilization at the earlier stage of stress was reduced in many brain regions. These findings suggested that noradrenergic neuronal activity in some specific brain regions, such as the hypothalamus and limbic areas, might be involved in the coping processes under a stressful situation. This hypothesis was supported by the results of Experiment 3 showing that the effects of stressor controllability on regional brain NA turnover were covaried with the complexity of coping task required. Taken together, it is concluded that the degree of behavioral control (the ability to alter the termination or duration) that an organism has over a stressor modulates the physiological and neurochemical impact of that stressor, and that brain NA is implicated in the learning process where an organism copes with a stressor.

Animals↗