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Biomedical subjects

H Hashimoto

Publications and source records attributed to H Hashimoto.

At least 1,045 records · Page 58Linked to original sources
PubMed1988

A calmodulin antagonist (W-7) and a protein kinase C inhibitor (H-7) have no effect on atrial natriuretic peptide release induced by atrial stretch.

The role of intracellular signals in the regulation of atrial natriuretic peptide (ANP) release was investigated using isolated rat left atria. Dibutyryl cyclic AMP and dibutyryl cyclic GMP had no effect on ANP release. Arginine vasopressin and phenylephrine, both of which activate the polyphosphoinositide system and consequently both the diacylglycerol-protein kinase C system and the Ca2+-Ca2+ receptor system, stimulated ANP release dose-dependently. The ANP release stimulated by phenylephrine was inhibited by N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), a calmodulin antagonist, and 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), a protein kinase C inhibitor. Atrial stretch stimulated ANP release, but the release was not inhibited by W-7 or H-7. These results suggest that the mechanism responsible for phenylephrine-induced ANP release differs from that for stretch-induced ANP release.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1988

The effects of lipoxygenase inhibitor and peptidoleukotriene antagonist on myocardial injury in a canine coronary occlusion-reperfusion model.

UNLABELLED: We studied effects of lipoxygenase inhibitor (AA-861) and peptidoleukotriene antagonist (ONO-1078) on infarct size, polymorphonuclear leukocyte (PMNs) infiltration, gross myocardial hemorrhage and ventricular arrhythmias in canine coronary occlusion (2 hr)-reperfusion (5 hr) model. Infarct size (IS) and risk area (RA) were determined by dual staining technique. Thirty minutes before coronary occlusion dogs were randomly assigned to one of the following three groups: lipoxygenase inhibitor group (n = 11) receiving AA-861 3 mg/kg i.v., peptidoleukotriene antagonist group (n = 11) receiving continuous intravenous infusion of ONO-1078 1 micrograms/kg/min and vehicle control group (n = 15). Both AA-861 and ONO-1078 reduced infarct size [AA-861: 21.8 +/- 1.3% of RA (mean +/- SEM), ONO-1078: 22.5 +/- 4.4% vs CONTROL: 54.0 +/- 6.4%, p less than 0.01 and p less than 0.01, respectively] and area of gross myocardial hemorrhage (AA-861: 5.1 +/- 2.4% of IS, ONO-1078: 5.2 +/- 2.5% vs CONTROL: 22.3 +/- 3.9%, p less than 0.01 and p less than 0.01, respectively). Both drugs also decreased frequency of ventricular premature contractions both during occlusion and during reperfusion, and that of ventricular tachycardia during reperfusion. AA-861 inhibited PMNs recruitment into infarcted area. However, ONO-1078 had no significant influence on degree of PMNs infiltration. These results suggest that lipoxygenase products, especially peptidoleukotrienes (LTC4, D4 and E4) may play important roles in the pathogenesis of myocardial ischemic and reperfusion injuries.

Animals↗
PubMed1988

Piston-pump-type high frequency oscillatory ventilation for neonates with congenital diaphragmatic hernia: a new protocol.

High frequency ventilation and extracorporeal membrane oxygenation (ECMO) are devices that are expected to save the lives of newborn infants whose pulmonary conditions have deteriorated. A piston-pump-type high-frequency oscillator (HFO), developed by Bryan and Miyasaka called "Hummingbird," is considered to be superior to high frequency "jet" ventilators or those of the flow-interrupter type, and was used successfully in two neonates with congenital diaphragmatic hernia (CDH) in a high-risk group. The first baby was on a conventional ventilator with pharmacologic support for the first 54 hours and then operated on. Postoperative deterioration necessitated the use of HFO for the next eight days. The infant then recovered uneventfully. For the second baby, HFO was necessary both preoperatively and postoperatively. This baby had a major diaphragmatic defect and her case was complicated with pneumothorax. There was a long stormy course on HFO (total, 70 days), but the patient was successfully extubated on the 75th day postoperatively and is now doing well. We believe active long preoperative stabilization with pharmacologic support and preoperative and postoperative hyperventilation with a piston-pump-type HFO may be a new innovative strategy for the management of severe CDH patients.

Female↗
PubMed1988

Benign schwannoma of the gastrointestinal tract: a clinicopathologic and immunohistochemical study.

A clinicopathologic and immunohistochemical review was made of 24 cases of distinctive nerve sheath tumors located in the gastrointestinal tract. The tumors were microscopically evident in the presence of peripheral lymphoid cuffing and benign nuclear atypia. The tumors arose in the muscularis propria of the stomach in 23 cases and in the ascending colon in 1 case. The patients included 9 men and 15 women whose ages ranged from 36 to 78 years (average, 58). No recurrence has developed in any patient who underwent resection. Although positive immunostaining for S-100 protein, Leu 7 antigen, and laminin might support the schwannian nature of these tumors, the positive immunoreactivity for glial fibrillary acidic protein (GFAP) indicated the possibility of a myenteric plexus origin. The pattern of S-100 protein immunostaining differed from that seen in cases of gastrointestinal stromal tumors associated with von Recklinghausen's neurofibromatosis or that noted in cases of conventional leiomyomas. We propose that these tumors be designated as benign schwannoma of the gastrointestinal tract.

Adult↗
PubMed1988

Fluorescence microscopy of nuclear DNA in oocytes and zygotes during in vitro fertilization and development of early embryos in mice.

Fluorescence microscopic investigations of nuclear DNA stained with mithramycin or 4',6-diamidino-2-phenylindole (DAPI) were undertaken in oocytes and zygotes during in vitro fertilization (IVF) and subsequent early embryo development in mice. Mithramycin and DAPI bind stoichiometrically with G-C and A-T pairs of DNA, respectively. In the present study, it was possible to visualize the germinal vesicle, the nucleolus, and the chromosome in the oocyte. After IVF, the nuclei, male and female pronuclei, polar bodies, nucleolus-associated chromatins, and chromosomes were successively observed in the zygote, the blastomere during cleavage, and the blastocyst until the hatching stage. The formation of male and female pronuclei, the process of their fusion, the appearance of the chromosome, and the commencement of the first cleavage of the zygote to form two blastomeres were all clearly demonstrated. The number of blastomeres was easily counted in the morula in spite of the compaction of the blastomeres. The present study indicates that the methods reported herein are useful for the determination of exact functional stages of the oocyte and the zygote during IVF and early embryo development, and thus contributes to the advancement of reproductive and developmental biomedical research.

Animals↗
PubMed1988

Sustained diacylglycerol formation in norepinephrine-stimulated rat heart is associated with alpha 1-adrenergic receptor.

We measured the amount of 1,2-diacylglycerol (DG) in rat hearts using thin-layer chromatography and a flame ionization detection technique, since 1,2-DG is thought to play a central role in the metabolism of phosphoinositide hydrolysis. In response to exogenous norepinephrine, a significant increase in 1,2-DG content in the myocardium was observed over 10-60 min, achieving an 80% increase over unstimulated controls at 60 min. On the other hand, the cholesterol content and six species of phospholipids were not significantly affected. In order to elucidate the mechanism of 1,2-DG accumulation elicited by norepinephrine, alpha- and beta-adrenergic antagonists were given. Pretreatment with phentolamine and prazosin, but not propranolol, inhibited the norepinephrine-induced 1,2-DG accumulation. Yohimbine appeared to have a partially inhibitory effect. These results suggest that myocardial norepinephrine-related 1,2-DG formation, which is likely to activate protein kinase C, is associated with alpha-adrenergic receptors, especially alpha 1-adrenergic receptors.

Adrenergic alpha-Antagonists↗
PubMed1988

Characteristics of Photosynthate Partitioning during Chloroplast Development in Avena Leaves.

The first leaves (40 millimeters long) of 4-day-old light-grown Avena sativa L. cv Victory I seedlings contained a complete age sequence of cells from the base to the tip, and within these tissues all stages of chloroplast development could be observed. Although chloroplasts underwent progressive development, a marked increase in number of thylakoids per granum, in chloroplast volume, and in chlorophyll content occurred in the region between 20 and 30 millimeters from the base. Photosynthetic CO(2) fixation (per unit chlorophyll) increased markedly during chloroplast development and closely followed structural changes in chloroplasts. It was also found that the partitioning of photosynthates differed greatly in the segment from 30 to 40 millimeters (at the tip of the leaf) compared with the segment nearer to the leaf base, although both total (14)CO(2) fixation and chlorophyll content per segment did not change significantly along the length of the leaves. As the thylakoid system reached full maturation, partitioning of photosynthates into sucrose increased but partitioning decreased into starch, lipids, and phosphorylated intermediates.

Journal Article↗
PubMed1988

Opsonic effect of fibronectin on staphylococcal phagocytosis by human polymorphonuclear leukocytes: its relative inefficiency in post-phagocytic metabolic activities and in intracellular killing.

The binding of 125I-labeled human plasma fibronectin (FN) to two strains of live Staphylococcus aureus (S. aureus) (a coagulase-positive Cowan I and a coagulase-negative Newman D2C) and the opsonic effect of FN on phagocytosis of these bacteria by human polymorphonuclear leukocytes (PMN) have been studied. 125I-FN bound to a similar extent in both staphylococcal strains. The 125I-FN-binding was significantly inhibited by human fibrinogen as well as unlabeled FN. The FN-binding was also reduced markedly by trypsinization of these bacteria, but the extent of its decrease did not correlate with their tryptic susceptibility of protein A and clumping factor. FN enhanced the uptake of these bacteria by PMN. However, its binding had no effect on superoxide anion (O2-) generation. The FN-binding definitely stimulated staphylococcal ingestion and intracellular killing by PMN, but the extent of such promotion was dissimilar between these two strains of bacteria. These results suggest that post-phagocytic metabolic activities as well as intracellular killing of these Staphylococci may also be greatly influenced by FN-unrelated factors as are other bacteria having no FN-receptors.

Agglutination↗
PubMed1988

The promoting effects of food dyes, erythrosine (Red 3) and rose bengal B (Red 105), on thyroid tumors in partially thyroidectomized N-bis(2-hydroxypropyl)-nitrosamine-treated rats.

The effects of erythrosine (Red 3), rose bengal B (Red 105) and thyroidectomy on the development of thyroid tumor were examined in male Wistar rats treated with N-bis(2-hydroxypropyl)nitrosamine (DHPN). Red 3 and Red 105 were used at 4% in the basal diet and were administered for 19 weeks from week 2 to 20. Thyroidectomy was performed by resection of the left lobe at week 4. Single injection of DHPN was performed intraperitoneally at 280 mg per 100 g body weight at the beginning of the experiment. Red 3 and Red 105 significantly promoted the development of thyroid tumors in thyroidectomized rats given DHPN, but had no significant effect in non-thyroidectomized rats. The incidence of thyroid tumors was 91% in rats with partial thyroidectomy, Red 3 and DHPN, 100% in rats with partial thyroidectomy, Red 105 and DHPN, and 64% in rats with partial thyroidectomy and DHPN. Serum TSH was 5.5 +/- 3.1 ng/ml in rats with partial thyroidectomy, Red 3 and DHPN, 2.1 +/- 2.2 ng/ml in rats with partial thyroidectomy, Red 105 and DHPN, and 1.5 +/- 0.5 ng/ml in rats with partial thyroidectomy and DHPN.

Animals↗
PubMed1988

Assay of 2-hydroxyputrescine in various regions of rat brain by gas chromatography-mass spectrometry.

2-Hydroxyputrescine in seven regions of single rat brains was measured with a sensitive, specific assay by gas chromatography-mass spectrometry. The regions were the cerebral cortex, cerebellum, medulla oblongata, hypothalamus, striatum, hippocampus, and midbrain. The level of 2-hydroxyputrescine was very high in the cerebral cortex and cerebellum, high in the medulla oblongata, hypothalamus, and hippocampus, and low in the striatum and midbrain. The level of 2-hydroxyputrescine in the cerebellum was significantly higher than in the striatum and midbrain.

Animals↗
PubMed1988

The negative inotropic effect of nicorandil is independent of cyclic GMP changes: a comparison with pinacidil and cromakalim in canine atrial muscle.

1. The negative inotropic effects of nicorandil, a nitrate with K-channel opening properties, have been compared with those of pinacidil, cromakalim and nifedipine, in canine right atrial muscle. 2. Cromakalim, pinacidil and nicorandil all produced a negative inotropic effect. However, even at their maximally effective concentrations, the force of contraction remained at about 10% of control levels, whereas contraction was abolished by nifedipine. 3. The pD2 values for the negative inotropic effects of cromakalim, pinacidil and nicorandil were 5.93, 5.37, and 4.35, respectively. 4. The negative inotropic effects of cromakalim (3 x 10(-5)M), pinacidil (3 x 10(-5) M and 3 x 10(-4) M) and nicorandil (3 x 10(-5) M) were not accompanied by changes in cyclic AMP and cyclic GMP levels, whereas that of 3 x 10(-4) M nicorandil was accompanied by an increase in cyclic GMP but not cyclic AMP concentrations. 5. The negative inotropic effect produced by 3 x 10(-4) M nicorandil was greatly reduced by 10(-2) M tetraethylammonium, whereas the increase in cyclic GMP produced by this concentration of nicorandil was not significantly changed. Sodium nitroprusside (10(-3) M) produced a large increase in cyclic GMP concentrations but had no significant negative inotropic effect. 6. It is concluded that the negative inotropic effects of nicorandil like those of cromakalim and pinacidil do not result from an increase in cyclic GMP concentrations. Instead these effects may be due to their action as K-channel openers.

Animals↗
PubMed1988

Chronic alcohol ingestion decreases pituitary-thyroid axis measures in Fischer-344 rats.

In a chronic feeding study adult male Fischer-344 rats (n = 12) were fed a nutritionally complete liquid diet containing 10% (w/v) ethanol for 40 days while control animals (n = 12) were pair fed a nutritionally complete isocaloric diet in which dextrose was substituted for ethanol. Treated animals were gradually introduced to and withdrawn from the 10% diet. At the end of the study and at sacrifice ethanol-fed rats had gained slightly more weight than pair-fed controls. They also showed a significant decrease in total thyroxine, free thyroxine, L-triiodothyronine, reverse L-triiodothyronine, and basal thyroid-stimulating hormone. These differences did not appear to result from caloric deprivation alone. Possible explanations for some of these thyroidal changes are discussed.

Alcoholism↗
PubMed1988

Changes in vascular reactivity in experimental diabetic rats: comparison with hypothyroid rats.

The responsiveness to vasoactive agents in the perfused mesenteric vascular bed of streptozocin-induced diabetic rats was examined and compared with that of propylthiouracil-induced hypothyroid rats. Diabetic rats at 4 and 8 weeks after the induction of diabetes showed a significant decrease in isoproterenol-induced vasodilatation. In addition, the contractile responses to norepinephrine and 5-hydroxytryptamine and the vasodilative response to acetylcholine were significantly decreased in 12-week-diabetic rats. The contractile response to nerve stimulation was markedly decreased at 8 and 12 weeks. On the other hand, hypothyroid rats showed a decreased response to isoproterenol, but they did not show any change in the response to nerve stimulation. A decrease in plasma thyroid hormone levels in diabetic rats at any time period was similar in extent to that in hypothyroid rats. The data indicate that the progressive changes in vascular reactivity in diabetic rats may be divided into two stages. In the early stage, the altered reactivity of vasculature is likely to be mediated by hypothyroidism, whereas in the later stage, it is induced by other factors, e.g. hyperglycemia and hypoinsulinemia. Adrenergic neuropathy is not caused by hypothyroidism.

Animals↗
PubMed1988

Complement subcomponent C1q in various strains of mice. Its serum content correlates with that of immunoglobulin G.

The protein amount and the hemolytic activity of the initiating complement component (C1q) in the classical pathway, and the level of immunoglobulin G (IgG) in sera of various inbred mouse strains were measured in parallel with those in sera of closed colony mice. C1q levels were significantly high in male A/He and C57BL/10Sn mice, and conspicuously high in female C57BL/10Sn mice. In these strains and C57BL/6J mice of both sexes, IgG levels were also significantly high. IgG levels were strikingly high in female NZB mice and NZW mice of both sexes. On the other hand, both C1q and IgG levels were conspicuously low in BALB/c mice of both sexes and in male CBA mice, and surprisingly low in BALB/c-nu (nude) mice of both sexes. A significant correlation was observed between serum levels of C1q and IgG. The C1q specific activity, however, was equivalent in all serum samples with approximately 2 x 10(13) effective molecules/mg. The subunit composition of C1q analyzed by polyacrylamide gel electrophoresis was well comparable within all strains of mice tested. These results may suggest that mouse serum C1q does not have any phenotypic polymorphism.

Animals↗
PubMed1988

Relation between the level of IgG subclasses and infections in patients with systemic lupus erythematosus.

IgG subclasses in sera from 48 patients with systemic lupus erythematosus (SLE) were examined by enzyme-linked immunosorbent assay (ELISA), and the relation between the level of IgG subclasses and infections was investigated. In patients with SLE, IgG2 and IgG4 decreased when compared to normal subjects. In patients with infections, IgG3 and IgG4 were decreased when compared to patients without infections. When the level of IgG3 was less than 60 microliter/ml and the level of IgG4 was less than 20 microliters/ml, infection was increased, especially mycotic infections. It was shown that the estimation of IgG3 and IgG4 serum levels served as important indices for infection.

Adult↗
PubMed1988

Improvement of pentobarbital-induced heart failure by MCI-154, a novel and potent cardiotonic agent, in the dog heart-lung preparation.

The efficacy of MCI-154, a new pyridazinone cardiotonic agent, in improving heart failure was assessed in dog heart-lung preparations in which cardiac function had been severely depressed by pentobarbital. MCI-154 in doses of 10-100 micrograms improved the cardiac function curve and restored it to the control level at 100 micrograms. At this dose, MCI-154 neither produced an increase in heart rate beyond the control value nor induced arrhythmias. The effects of MCI-154 were not affected by atenolol, a cardioselective beta 1-blocker. These results indicate that MCI-154 would be of potential use in the treatment of heart failure.

Animals↗