Biomedical subjects

H Hashimoto

Publications and source records attributed to H Hashimoto.

At least 433 records · Page 24Linked to original sources

PubMed1997

Vasoactive intestinal polypeptide and pituitary adenylate cyclase-activating polypeptide receptor chimeras reveal domains that determine specificity of vasoactive intestinal polypeptide binding and activation.

Vasoactive intestinal polypeptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) receptors are closely related G protein-coupled receptors with seven-transmembrane domains. The VIP receptor can bind both VIP and PACAP with high affinity, whereas the PACAP receptor binds only PACAP with high affinity. To elucidate the structural domains involved in a selectivity for VIP binding and the subsequent receptor activation, a series of chimeric receptors between the VIP and PACAP receptors was constructed, expressed in COS-7 cells, and analyzed for ligand binding and cAMP generation. All chimeric constructs bound PACAP with high affinity and subsequently activated cAMP generation similarly to the wild-type receptors. In contrast, profound differences were observed in the potencies of VIP for competition of 125I-labeled PACAP binding to both wild-type receptors and the chimeric receptors. The cAMP responses of these receptors generally correlated with the ability of VIP to compete for PACAP radioligand binding with the exceptions for some particular chimeras. In this report we demonstrate that several domains, including the amino-terminal extracellular domain, the transmembrane domains I and II, and the first extracellular loop of the VIP receptor, are important for the selectivity for VIP binding and responsiveness to VIP. We further show that the third extracellular loop and its proximal domains of the VIP receptor appear to be involved in the VIP recognition, especially the receptor activation process. On the other hand, the direct binding experiments of the VIP radioligand demonstrated that both wild-type receptors and all chimeric receptors have a high affinity binding site for VIP, although this high affinity VIP binding resulted in a biological response only in the VIP receptor or VIP receptor-like chimeras. This suggests that there is a nonbiologically relevant high affinity VIP-binding site within the rat PACAP receptor.

Amino Acid Sequence↗

PubMed1997

Human immunodeficiency virus type 2 envelope glycoprotein binds to CD8 as well as to CD4 molecules on human T cells.

We report here that human immunodeficiency virus type 2 (HIV-2) envelope glycoprotein (gp105), but not HIV-1 gp120, can bind to CD8 molecules as well as to CD4 molecules on human T cells. This phenomenon may lead to differences in the life cycles of HIV-1 and HIV-2, and it may be related to the differences in disease manifestations of HIV-1 and HIV-2 infection, including longer survival of HIV-2-infected patients.

CD4 Antigens↗

PubMed1997

Presence of Turner stigmata in a case of dysgenetic male pseudohermaphroditism with 45,X/46,X+mar karyotype.

A case is reported of dysgenetic male pseudohermaphroditism (DMPH) having Turner stigmata and 45,X/46,X+mar karyotype. The marker chromosome of this patient consisted of most if not all of the short arm, including the sex determining region of the Y chromosome. Although this karyotype is relatively common in Turner's syndrome and occasionally observed in mixed gonadal dysgenesis, DMPH is usually exemplified by a 46,XY karyotype except for one patient reported with 45,X/46,XY mosaicism. Turner stigmata have not previously been reported in DMPH. The present patient is an intermediate case between mixed gonodal dysgenesis and typical DMPH, and this indicates that 45,X/ 46,X +mar karyotype abnormality can result in a wide range of phenotype such as DMPH, mixed gonodal dysgenesis and Turner's syndrome.

Disorders of Sex Development↗

PubMed1997

Analgesic effect of a herbal medicine for treatment of primary dysmenorrhea--a double-blind study.

We evaluated the analgesic effect of Toki-shakuyaku-san (TSS) in women who had a combination of "deficiency," of "Yin," "cold," and "stagnated blood" syndromes, and were suffering from dysmenorrhea. A diagnostic scoring system was used for determination of these conditions. We treated patients with either TSS or placebo during 2 menstrual cycles with a double-blind technique, and we followed them for 2 additional cycles. A significant alleviation of dysmenorrhea was observed in patients treated with TSS as compared to those treated with placebo. Our results suggest that TSS is effective for treatment of dysmenorrhea in patients with the above-mentioned conditions.

Adolescent↗

PubMed1997

Experimental IgA nephropathy induced by a low-dose environmental mycotoxin, nivalenol.

Based on the hypothesis that IgA nephropathy (IgAN) is triggered by some exogenous antigen(s) which induces dysregulation of the mucosal immune system, we developed an experimental model of orally induced IgAN by an environmental mycotoxin, nivalenol (NIV), which often contaminates agricultural products in Southeast Asia and Japan. In the present study, low doses of oral NIV reproducibly induced significant IgA deposits in the glomerular mesangium and elevated serum IgA levels in mice irrespective of the strain; the degree of immunopathological changes analogous to human IgAN was associated with the dose and duration of NIV treatment. Furthermore, a competitive enzyme-linked immunosorbent assay with an NIV analogue-protein conjugate disclosed that the IgA antibody in the sera from the NIV model mice had a higher affinity to the mycotoxin. Conclusively, these findings suggest that NIV induces some pathological changes in mice which resemble those in human IgAN, and that this mycotoxin is associated with pathogenesis in some types of glomerulonephritis.

Animals↗

PubMed1997

Anti-Thy-1 antibody provokes reverse passive cutaneous anaphylaxis-like reactions.

Antibodies to rat Thy-1, and also to murine Thy-1, could provoke reverse passive cutaneous anaphylaxis-like (RPCA-like) reactions. The threshold amount of purified anti-Thy-1 antibodies for RPCA-like reactions was 12.5 microg/ml. No RPCA-like reactions were obtained with IgG1 F(ab')2 anti-Thy-1. Cross-linking the murine anti-rat Thy-1 F(ab')2 fragments with goat antibody against murine F(ab')2 anti-rat Thy-1 permitted us to obtain RPCA-like reactions with as little as 1.5 microg/ ml. However, when the cross-linking was done with the F(ab')2 of the same goat antibody, no RPCA-like reactions were obtained. The antibody against rat FcepsilonRIalpha or its F(ab')2 product were equally effective in producing RPCA-like reactions; the threshold was obtained with 1.5 microg/ml. The mechanism of the difference is discussed.

Animals↗

PubMed1997

Serial assessments of middle cerebral artery flow velocity with transcranial Doppler sonography in the recovery stage of eclampsia. A case report.

The pathophysiologic changes of eclampsia and/or hypertensive encephalopathy are unclear. Changes of middle cerebral artery flow velocity during the recovery stage in a case of eclampsia are reported. After the disappearance of signs and symptoms, the flow velocity began to increase, owing probably to delayed vasospasm, which was confirmed by magnetic resonance angiography. The vasospasm may be a consequence of eclampsia and may be of small significance in the pathogenesis.

Adult↗

PubMed1997

Surface characterization of amalgam made with Hg-In liquid alloy.

When amalgam was triturated with Hg-In liquid alloys instead of pure mercury, the resultant amalgams released a significantly smaller amount of mercury vapor during setting. To understand the mechanisms responsible for the drastic decrease in mercury evaporation from the In-containing amalgam, we used Auger Electron Spectroscopy to examine surface oxide films on amalgams made with Hg-10 wt% In or pure mercury. The surface of the In-containing amalgam was rapidly covered with both indium and tin oxide films. Greater amounts of oxygen were found on the gamma 1 Ag-Hg matrix in the In-containing amalgam than in the amalgam without indium. The rapid formation of the oxide film contributes to a reduction in the mercury release from the In-containing amalgam by forming an effective barrier to evaporation.

Copper↗

PubMed1997

Effects of astemizole on ventricular activation delay and RT intervals in a canine myocardial infarction model.

In order to clarify the arrhythmogenic effects of nonsedating antihistamines, we examined the effects of astemizole, a nonsedating antihistamine, on ventricular activation and RT intervals in a canine myocardial infarction model. Myocardial infarction was produced by two-stage ligation of the left anterior descending coronary artery in dogs. Seven days after ligation, bipolar electrodes were sutured on the ventricular surface of the infarcted and normal zones to apply an electrical stimulation or record the ventricular activation. An electrical stimulation with coupling intervals between 300 and 140 ms was applied on the ventricular surface of the normal zone during atrial pacing, and the ventricular activation delay was measured. The effect of astemizole on the RT interval was also determined during atrial pacing, sinus rhythm or after premature stimulation. The ventricular activation delay increased after astemizole at doses of 0.3 to 3 mg/kg in the infarcted and at 3 mg/kg in the normal zones, and the effect of astemizole was greater in the infarcted zone. Astemizole increased the RT interval in the normal zone to a greater extent at a long coupling interval. The increase in the RT interval was greater in the infarcted zone compared with that in the normal zone. In conclusion, astemizole increased the activation delay in the infarcted zone, probably through prolongation of the repolarization time, and its effect on the activation delay may be arrhythmogenic.

Animals↗

PubMed1997

Electrophysiologic effects of nitrous oxide, a volatile anesthetic, in dogs following myocardial infarction in comparison with other anesthetics.

The present study was undertaken to examine the electrophysiologic effects of nitrous oxide in the dog heart after inducing myocardial infarction, and to compare these with those of other anesthetics. Myocardial infarction was produced by two-stage ligation of the left anterior descending coronary artery in dogs. Seven days after ligation, bipolar electrodes were sutured on the ventricular surface of the infarcted and normal regions for applying electrical stimulation or recording ventricular activation. Ventricular activation time and QT interval on the bipolar electrocardiogram and PQ interval from the standard limb lead II were measured during atrial pacing. Nitrous oxide 80% did not significantly prolong ventricular activation time, PQ interval or QT interval. However, halothane 1 minimum alveolar concentration (MAC), thiopental 5 and 10 mg/kg and fentanyl 30 microg/kg did prolong ventricular activation time; thiopental and fentanyl prolonged the QT interval. Nitrous oxide did not potentiate the effects of fentanyl. Therefore, electrophysiologic effects of nitrous oxide are much weaker compared with those of thiopental, fentanyl or halothane.

Anesthetics, Inhalation↗

PubMed1997

Pituitary adenylate cyclase-activating polypeptide (PACAP) receptor mRNA in the rat adrenal gland: localization by in situ hybridization and identification of splice variants.

The distribution of mRNA for pituitary adenylate cyclase-activating polypeptide receptor (PACAP-R) was examined by in situ hybridization in rat adrenal gland. In the adrenal medulla, PACAP-R mRNA was expressed in almost all chromaffin cells without any significant expression in the cortical region. Using the reverse transcription-polymerase chain reaction, we analyzed the mRNA expression of PACAP-R splice variant forms in the adrenal gland. The predominant forms observed were the variant having a 28-amino acid insert in the third intracellular loop (termed PACAP-R-hop1). As PACAP is localized in the noradrenaline secreting cells of the adrenal chromaffin cells, and stimulates catecholamine release, the present results suggest that PACAP may serve as a paracrine or autocrine regulatory factor for the chromaffin cells through PACAP-R.

Adrenal Glands↗

PubMed1997

An established hybridoma clone producing a monoclonal antibody against Vibrio anguillarum.

Vibrio anguillarum is a pathogenic microorganism of vibriosis, an infectious disease found in various fish species. A mouse hybridoma clone, named C5, that produced a monoclonal antibody to V. anguillarum was established. The specific reaction of C5 antibody with V. anguillarum was confirmed by the pre-adsorption effect of the V. anguillarum cells in ELISA and a cell immunoprecipitation experiment. Western blotting analysis indicated that the C5 antibody recognized a high molecular weight substance extracted from cells with detergents.

Animals↗

PubMed1997

Talc and amosite/crocidolite preferentially deposited in the lungs of nonoccupational female lung cancer cases in urban areas of Japan.

To analyze the correlation between asbestos lung burden and lung cancer, lungs of 211 female cases with and without lung cancer were examined. Phase-contrast microscopic (PCM) counting of ferruginous (FBs) and uncoated fibers (UFs), which had length longer than 5 microns and aspect ratios greater than 3:1, revealed a significantly higher level of FBs plus UFs in urban lung cancer cases than urban non-lung cancer cases (1380.5 vs. 550.3; p < 0.001). No difference was noted between rural lung cancer and non-lung cancer cases. Analytical electron microscopic studies identified various kinds of mineral fibers with an aspect ratio greater than 3:1 in the lung tissue including chrysotile, actinolite/tremolite, amosite/crocidolite, fibrous talc, mica, silica, iron, wollastonite, chlorite, kaoline, and others. The most frequently detected fibers were thin, short chrysotile fibers, most of which could not be found by PCM, followed by relatively thick, long actinolite/tremolite fibers, fibrous talc, and in a smaller number, amosite/crocidolite of intermediate length and width. Amosite/crocidolite and fibrous talc counts in urban lung cancer cases were greater than those of urban non-lung cancer cases, rural lung cancer, and rural non-lung cancer cases; these findings were consistent with PCM analysis. Therefore, it is suggested that fibers detected in PCM observation may be mainly amosite/crocidolite with some parts fibrous talc and that fibrous talc in urban environments may be another candidate for carcinogenic or cocarcinogenic factors of female lung cancer.

Adult↗

PubMed1997

Effects of chronic treatment with carvedilol on smooth muscle tone and endothelium-dependent relaxation of aorta in stroke-prone spontaneously hypertensive rats.

Effects of chronic treatment of stroke-prone spontaneously hypertensive rats (SHRSP) with carvedilol, an agent which has both alpha and beta-adrenoceptor blocking actions, on spontaneous muscle tone and on structural and functional abnormalities of endothelium were studied. The treatment of SHRSP with the drug of the dose of 30 to 200 mg/kg/day lowered the blood pressure significantly. Spontaneous muscle tone in endothelium-removed preparation disappeared by the treatment. Noradrenaline-induced contraction was depressed by the treatment in endothelium intact preparation but not in endothelium removed preparation. The treatment prevented the structural and functional abnormalities of endothelium. Similar results were obtained by the treatment with propranolol. These results indicate that carvedilol prevented abnormal contraction of SHRSP aorta through protective effects on smooth muscle and endothelium. These effects may play roles in blood pressure lowering effect of carvedilol.

Adrenergic alpha-Antagonists↗

PubMed1997

Fetal cavernous angioma--case report.

A neonate male who developed cavernous angioma was born with a severe intraventricular hemorrhage and intraparenchymal hemorrhage in the basal ganglia. magnetic resonance imaging revealed a large, non-enhanced hematoma that packed the lateral ventricle. Surgery on the 2nd day of life verified a cavernous angioma associated with minimal hemosiderin and gliosis. Fetal cavernous angiomas, unlike such malformations in other age groups, can present with a devastating hemorrhage because of the lack of gliosis in the surrounding brain.

Cerebral Hemorrhage↗

PubMed1997

Recurrent Lhermitte-Duclos disease--case report.

A 43-year-old male presented with recurrent Lhermitte-Duclos disease (LDD), a rare pathological entity of the cerebellum of which the etiology is still controversial. He had undergone subtotal removal of a cerebellar lesion, misdiagnosed as a benign astrocytoma, 8 years previously. Subtotal removal of the recurrent tumor completely resolved the presenting symptoms. Recurrence of LDD is not as rare as generally assumed. Patients with LDD require long-term observation even when the initial treatment appeared curative.

Adult↗

PubMed1997

[A case of reactive arthritis fallen after shigellosis infection].

A 25-year-old woman was admitted for general arthralgia in July, 1989. Reactive arthritis with arthralgia after Shigellosis was diagnosed by sex, localization of arthralgia and positive for HLA-B 27. Within 3 weeks after starting diclifenac sodium 75 mg/day, the arthralgia remitted. It has been reported that patients who are positive for HLA-B 27 have a more severe acute or chronic sacroiliitis, and our case may support this report.

Adult↗

PubMed1997

[Relapsing polychondritis: a case with respiratory failure].

A 48-year-old woman was admitted to our hospital with respiratory failure (Hugh-Jones IV-V). She was diagnosed as relapsing polychondritis 6 years ago. Her respiratory failure was due to pharyngial stenosis, deformity and inflammation of a trachea and lobar bronchus, and bronchial collapse. Her tracheobronchochondritis was managed by 500-700 mg/day of hydrocortisone and 50 mg/day of cyclophosphamide. Laboratory examination revealed only slight elevation of CRP and no elevation of anti-type II collagen antibody, although these parameters were very high on her first admission when she had severe polyarthritis, polychondritis of nose and auricles. Bronchoscopic findings were compatible with tracheobronchomalacia since pharyngial stenosis due to inflammatory pharyngitis and bronchial collapse due to tracheobronchochondritis were shown without lung parenchymal damage. We referred to the literature on tracheobronchomalacia which was associated by the varieties of respiratory and rheumatic diseases.

Female↗