Search PubMed⌕ Search

Biomedical subjects

M Yoshioka

Publications and source records attributed to M Yoshioka.

At least 325 records · Page 18Linked to original sources
PubMed1992

[Peripheral serotonin receptors: respiratory and circulatory modulation].

The wide distribution of serotonin (5-HT) receptors and 5-HT-mediated effects suggest that 5-HT has important physiological and/or pathophysiological roles in the peripheral nervous system. Recent studies about the localization and release of 5-HT in the peripheral nervous system suggest that 5-HT likely plays a functional role in regulating discharge of autonomic neurons and modulating sensory afferent neurons. The electrophysiological approach has the merit of measuring a direct effect of 5-HT on its receptor. In this review, much of our described work focuses on effects mediated via 5-HT3-receptors on respiration and circulation using electrophysiological techniques, and we consider whether these actions of 5-HT have physiological and/or pathophysiological significance.

Animals↗
PubMed1992

Granulomatous hypophysitis with meningitis and hypopituitarism.

We report an unusual case of granulomatous hypophysitis in which visual impairment, meningitis and hypopituitarism in a 76-year-old female were associated with radiological evidence of a pituitary mass. The sellar lesion was indistinguishable from pituitary tumor on neuroimaging studies, but the recovery of visual acuity and visual field abnormalities together with the improvement of pituitary function after steroid administration indicated that the mass lesion was due to an inflammatory disease of the pituitary gland. The pituitary tissue obtained by transsphenoidal hypophysectomy revealed granulomatous inflammatory cell infiltration with epithelioid cells and scattered multinucleated giant cells. Although a causal relationship with meningitis was not ascertained, possible exposure of the CSF space to the autoimmune inflammatory process of the pituitary gland was likely in view of the positive pituitary antibody reaction and radiological evidence of suprasellar extension. This entity should be considered when evaluating patients with a pituitary mass, hypopituitarism and meningitis.

Aged↗
PubMed1992

[BEP (bleomycin, etoposide, cisplatin) therapy for testicular tumors].

We describe our experience with BEP (bleomycin, etoposide, cisplatin) therapy as chemotherapy for testicular tumors in 11 patients. Eight were non-seminomatous testicular cancer patients and 3 were seminoma patients. Three of 8 non-seminomatous testicular cancer patients had no evident metastasis and BEP therapy was performed for prophylaxis of recurrence. Other 5 non-seminomatous testicular cancer patients and 3 seminoma patients had metastatic lesions and BEP therapy was performed to cure these metastatic lesions. Ten of our 11 patients are living and disease-free. One non-seminomatous testicular cancer patient who had brain, lung, eye and bladder metastases and had an extremely elevated human chorionic gonadotropin (hCG) level responded only partially and died later due to disease progression. Side effects in most patients were nausea, vomiting, alopecia and leucopenia and all these side effects were reversible. Neuromuscular toxicity such as paresthesia or abdominal cramp that is sometimes encountered in PVB (cisplatin, vinblastine, bleomycin) therapy was not seen in our patients. Our results support the concept that BEP therapy is better than PVB therapy as an initial chemotherapy for testicular tumors.

Adolescent↗
PubMed1992

The use of combined in situ hybridization and immunocytochemistry to identify HIV-infected cells in brain tissue.

It is frequently important to identify the types of cells that are infected with human immunodeficiency virus type-1 (HIV-1) in sections of formalin-fixed paraffin-embedded (FFPE) brain tissue. Currently, both immunocytochemical and in situ hybridization methods are used for this purpose. Combined in situ hybridization and immunocytochemistry results in simultaneous detection of HIV-1 nucleic acids and proteins and allow comparison of transcriptional and translational events of cells infected with HIV-1 in the same section. In addition, this technique allows morphologic and immunologic identification of the cells within which in situ hybridization occurs and confirmation of the identity of the cells that are not hybridized. Procedures are described for use with FFPE brain tissue.

Brain↗
PubMed1992

A central nervous system action of nitric oxide in blood pressure regulation.

We had reported that the systemic administration of N omega-methyl-L-arginine (L-NMA), a specific inhibitor of nitric oxide (NO) synthesis from L-arginine (ARG), raises arterial blood pressure (BP) while paradoxically enhancing central sympathetic outflow. Cervical spinal cord transection abolishes the increase in sympathetic outflow and attenuates the pressor effect of L-NMA. Thus, in addition to lowering BP by direct vasorelaxation, NO may also act in the central nervous system to reduce vascular sympathetic tone. To test this hypothesis we have injected L-NMA directly into the central nervous system in anesthetized rats. Intracisternally (i.c.), L-NMA elicited a small pressor response accompanied by a marked increase in sympathetic renal nerve activity (RNA). In contrast, the inactive stereoisomer N omega-methyl-D-arginine had neither pressor nor neural effects. The increases in RNA and BP elicited by i.c. L-NMA were abolished by spinal cord transection at C1 to C2 and by the i.v. administration of ARG. When administered i.c., ARG also abolished the increase in RNA elicited by i.v. L-NMA and significantly attenuated the pressor response. Thus, our findings indicate that L-NMA acts centrally by an ARG-reversible mechanism in the anesthetized rat to stimulate sympathetic nerve activity. Inasmuch as centrally synthesized NO has been postulated to play a second messenger and/or neurotransmitter role, our findings suggest that one such function would be the central regulation of sympathetic outflow and hence, BP.

Animals↗
PubMed1992

[Evaluation of platelet aggregation test by grading curve].

In order to standardize the platelet aggregation test, we used the grading curve (GC) produced by plotting four concentrations (0.5, 1.0, 2.0 and 4.0 microM) of ADP and four concentrations (0.25, 0.5, 1.0 and 2.0 micrograms/ml) of collagen, which are aggregation inducers, along the horizontal axis and plotting their individual rates (%) of aggregation 5 minutes after administration, along the longitudinal axis. The degree of platelet aggregation was classified in 6 stages (Types III, II, I, 0, -I and -II), ranging from marked increase to marked decrease, according to the GC of ADP aggregation in healthy subjects. Type I or 0 ADP aggregation was observed in 78% of the subjects, and Type I collagen aggregation was observed in about 50% of the subjects, whereas patients with cerebral infarction showed distinct increases in Type III and II aggregations of both ADP and collagen. In most patients who were treated with antiplatelet drugs, the aggregation were Type 0, -I or -II. The concentration of inducer, which corresponded to the maximum 50% value of the GC (Max 50) was significantly correlated with the minimum concentration (threshold concentration) in ADP aggregation, at which secondary aggregation was induced even if it was reversible, and with the minimum concentration (threshold concentration) in collagen aggregation, at which the aggregation rate 5 minutes after administration increased to 50% or higher. The GC of platelet aggregation seemed to enable easy determination of the degree of aggregation, and was also considered to be useful for monitoring platelet aggregation during the administration of antiplatelet drugs.

Adult↗
PubMed1992

[Ectopic ureter opening to vestibule without urinary incontinence: a case report].

A case of a 2-year-old female with right ectopic ureter opening in vestibule vaginae and without urinary incontinence is reported. Excretory urogram showed mild dilatation of the upper right segment with bilateral complete duplication. Right ectopic ureter some functioning upper segment of the kidney was reimplanted into the bladder to avoid surgical intervention for heminephrectomy. According to the retrograde ureterogram of ectopic ureter the running courses and shapes of the dilated distal portions of ureters were compared between two groups, ectopic ureter with incontinence and that without incontinence. We suppose the continence mechanism of ectopic ureter is kept when the running course of the ureter through some portion of the urethral sphincter musculature.

Anastomosis, Surgical↗
PubMed1992

Relationship among cardiac sympathetic nerve activity, blood pressure and heart rate during infusion of carperitide in rats.

The effect of the infusion of carperitide (alpha-human atrial natriuretic peptide; alpha-hANP) on cardiac sympathetic nerve activity, blood pressure and heart rate was studied in anesthetized rats. Intravenous infusion of carperitide (0.1 and 1.0 micrograms/kg/min) produced mild and dose-related decreases in mean arterial pressure without significant changes in cardiac sympathetic nerve activity or heart rate. In debuffered rats, carperitide (1.0 micrograms/kg/min) also produced a mild decrease in mean arterial pressure. No significant changes in cardiac sympathetic nerve activity or heart rate were observed. A significant correlation between changes in heart rate and cardiac sympathetic nerve activity was noted during infusion of carperitide and deafferentation did not alter this relationship. In contrast, no significant correlation was observed between changes in cardiac sympathetic nerve activity and blood pressure during infusion of carperitide in either buffer nerve intact or debuffered rats. These results suggest that the reduction of blood pressure induced by intravenous infusion of carperitide may not trigger the baroreceptor-mediated cardiac sympathoexcitation and this inhibition of baroreflex may be responsible for the anti-tachycardic effect of carperitide.

Animals↗
PubMed1992

Pharmacological characterization of 5-hydroxytryptamine-induced apnea in the rat.

To improve the pharmacological characterization of the receptors mediating 5-hydroxytryptamine (5-HT)-induced apnea the inhibitory effects of exogenous 5-HT on respiration and phrenic nerve activity (PNA) were studied in anesthetized rats. The effects of putative 5-HT receptor agonists and antagonists on respiratory parameters were examined. During spontaneous respiration the bolus i.v. injection of 5-HT (3.125-25 micrograms/kg) produced a transient apnea, the duration of which increased in a dose-related manner. In addition, during artificial respiration 5-HT produced a silent response of PNA, the duration of which increased dose-dependently. These responses were significantly antagonized by GR38032F, a selective 5-HT3 receptor antagonist. Ketanserin (100 micrograms/kg) and methysergide (100 micrograms/kg), 5-HT2 receptor antagonists, also inhibited the 5-HT-induced apnea. These effects of 5-HT on respiration were mimicked by 2-methyl-5-HT (3.125-25 micrograms/kg), a selective 5-HT3 receptor agonist, and by a high dose of alpha-methyl-5-HT, a 5-HT2 receptor agonist, but not by 5-carboxamidotryptamine, a 5-HT1-like receptor agonist. Lung compliance was greatly reduced and lung resistance greatly increased by 5-HT (3.125-25 micrograms/kg). The 5-HT-induced changes in lung compliance and lung resistance were antagonized markedly by both ketanserin (100 micrograms/kg) and methysergide (100 micrograms/kg), but not by GR38032F (100 micrograms/kg). Bilateral vagotomy above the nodose ganglia completely prevented both the changes in PNA and the apnea induced by 5-HT. These actions of 5-HT were not prevented, however, by cervical vagotomy below the level of the nodose ganglion. On the other hand, this cervical vagotomy completely blocked the alpha-methyl-5-HT-induced apnea.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1992

[Usefulness of transcutaneous gas monitoring during hemorrhagic shock].

This study was undertaken to confirm whether transcutaneous (tc) gas analysis during hemorrhagic shock could be used as an alternative to mixed venous gas analysis. Tc gases were measured and correlated with arterial and mixed venous gases in 10 anesthetized dogs during hemorrhagic shock and volume resuscitation. Throughout this experiment PtcO2 correlated well with PvO2 (r = 0.78, P less than 0.01), while PaO2 remained mostly constant, and PtcCO2 correlated well with PvCO2 (r = 0.82, P less than 0.01) rather than with PaCO2 (r = 0.63, P less than 0.01). A more detailed observation showed that during progressively decreased cardiac output, PtcO2 became lower than PvO2 and PtcCO2 became higher than PvCO2. We inferred from these observations that the changes of tc and mixed venous gases reflected those gases in tissues and that during severe shock maldistribution of peripheral blood flow prevented mixed venous gases from coming into equilibrium with tissue and tc gases. We conclude that the measurement of tc gases during shock is a more convenient and more reliable monitor of tissue gases than mixed venous analysis.

Animals↗
PubMed1992

[Effect of serum factors on the differentiation of a colon cancer cell line Caco-2].

A human colon cancer cell line Caco-2 undergoes spontaneous enterocytic differentiation under the standard culture condition. We examined the changes in the proliferative activity of Caco-2 cells during the differentiation, and the effect of serum factors on this spontaneous differentiation. Caco-2 cells cultured in FCS-containing media exhibited the differentiation phenotypes such as dome formation and increase of ALP activity after the 6th day of culture. Cell cycle analysis showed a marked decrease in S phase cell population during the cell differentiation. When Caco-2 cells were cultured in FCS free media, the cell population of S phase remained unchanged during culture period and the differentiation phenotypes were not induced. The addition of FCS to Caco-2 cell cultured in the absence of FCS resulted in the rapid induction of the differentiation phenotypes. These results suggest that differentiation of Caco-2 cells is closely related to the reduction of cell proliferation and requires some factors in FCS.

Animals↗
PubMed1992

[Detection of interferon-gamma and IL-6 producing cells in cerebrospinal fluid cells in the central nervous system infectious diseases using immunocytochemistry].

To evaluate the relationship between cytokines and cerebrospinal fluid (CSF) cells, we detected interferon (IFN)-gamma and interleukin (IL)-6 producing cells in CSF from the patients with central nervous system (CNS) infectious diseases by immunocytochemistry. Five CSF cell smears from three herpes encephalitis patients, three from a patient with EB virus radiculoneuritis, four from the three patients with purulent meningitis, five from five patients with viral meningitis were obtained during early or subacute stages of diseases. Control CSF cell smears were taken from twenty seven patients with motor neuron disease, Parkinson's disease and spinocerebellar degeneration. Immunocytochemistry using specific polyclonal anti-IFN-gamma and IL-6 sera were used to detect each producing cell. Simultaneously, individual positively immuno-reactive cells were morphologically classified macrophage or lymphocyte. The IFN-gamma positive cells immunostained with specific antibody showed brown-colored deposits within the cytoplasm whereas no deposit was in the nucleus (Fig. 1). These phenotype of IFN-gamma positive cells were considered to be lymphocytes or macrophages. However, IFN-gamma-positive macrophages were predominantly seen at the early stages of herpes simplex encephalitis and purulent meningitis. The percent of IFN-gamma positive cells in total CSF cells obtained from the patients with the CNS infectious diseases was 2.3-38.7 as shown in Table 1. The IL-6 positive cells (Fig. 2) were also found early in the course and in subacute stages in the CNS infectious diseases and ranged from 2.5-50 percent in total CSF cells (Table 1). In contrast neither IFN-gamma- nor IL-6-positive cells were detected in non-inflammatory diseases (Table 1).(ABSTRACT TRUNCATED AT 250 WORDS)

Central Nervous System Diseases↗
PubMed1992

[Clinical and preclinical pharmacology of KC-764, a novel antiplatelet agent].

Preclinical pharmacological studies showed that KC-764 was more potent and more selective in inhibiting platelet aggregation than aspirin. The concentration of KC-764 for inhibiting PGI2 production in the aorta was 70 times higher than that for inhibiting TXA2 in platelets. Antiplatelet action of KC-764 was augmented by plasma components. This augmentation by plasma may lead to selective antiplatelet activity. KC-764 has been investigated for platelet function in patients with chronic cerebral infarction. KC-764 at 10, 20 and 40 mg b i d, inhibited platelet aggregation induced by arachidonic acid, collagen, and ADP, and its potency was almost equal to aspirin at 100-330 mg daily. Plasma TXB2 levels were markedly depressed by KC-764 but plasma 6-keto-PGF1 alpha levels were not influenced. On the contrary, aspirin depressed both plasma prostanoids. These findings suggest that KC-764 can overcome the 'aspirin dilemma'.

Adenosine Diphosphate↗
PubMed1991

Specificity of the Mnt protein determined by binding to randomized operators.

The relative binding affinities of Mnt protein from bacteriophage P22 are determined for each possible base pair at position 17 of the operator. These are determined from the partitioning of randomized operators into bound and unbound fractions; quantitation is provided by restriction enzyme analysis. Mnt protein is found to have an unusual specificity at this position: a C.G base pair (the wild-type operator) has the highest affinity, a G.C base pair has the lowest affinity, and both orientations of A.T base pairs are intermediate and nearly equivalent. A specific binding constant and specific binding free energy are defined and shown to be directly related to the information content of the operator sequences bound to the protein, taking into account the quantitative differences in binding affinities.

Bacteriophages↗