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Biomedical subjects

H Sawada

Publications and source records attributed to H Sawada.

At least 163 records · Page 9Linked to original sources
PubMed1997

[Concealed infective endocarditis].

The occurrence of concealed infection or "natural remission" in infective endocarditis was investigated microscopically in 35 consecutive patients (36 valves) with infective endocarditis (between April 1987 and May 1995). Four patients were considered as having concealed or silent infective endocarditis. Preoperative diagnosis of these patients was mitral valve prolapse, rheumatic aortic valve stenosis with insufficiency, aortic valve prolapse and hypertrophic cardiomyopathy, respectively. These patients did not present with any clinical signs of infective endocarditis such as cardiac murmur and ventricular dysfunction. Histological examination of the excised valves revealed valvular perforation, small round cell infiltration, neovascularization, remnants of vascular smooth muscle cells, and organizing vegetations. These findings are consistent with the histological findings of infective endocarditis. Latent infective endocarditis may be present without inflammatory manifestation.

Aortic Valve Insufficiency↗
PubMed1997

Serum concentrations of free ubiquitin and multiubiquitin chains.

Ubiquitin, which can conjugate with cellular proteins, is classified into two forms: free ubiquitin and multiubiquitin chains. The latter is active as a signal for degradation of the targeted proteins. We found both forms in human serum and, using two immunoassays, quantitated them in sera from healthy subjects and patients with some diseases. Because of putative leakage of erythrocyte ubiquitin, hemolytic serum and serum obtained after long incubation (> 1-2 h) of blood at room temperature were excluded. Serum concentrations of multiubiquitin chains and free ubiquitin were substantially higher in rheumatoid arthritis and hemodialysis patients, respectively, than healthy subjects. Additionally, in acute viral hepatitis, serum multiubiquitin chain concentrations were increased in the acute phase, decreased in the recovery phase, and correlated with alanine and aspartate aminotransferase activities (r = 0.676 and 0.610, P < 0.0001 and < 0.001, respectively). Therefore, serum ubiquitin may have prognostic value.

Acute Disease↗
PubMed1997

[Allogeneic peripheral blood stem cell transplantation for multiple myeloma].

We report here with a 46-year-old man with refractory multiple myeloma receiving allogeneic peripheral blood stem cell transplantation from his HLA-matched brother. The preparative regimen consisted of TBI (12Gy), VP16 (15 mg/kg) and cyclophosphamide (120 mg/kg). GVHD prophylaxis consisted of cyclosporin A and short course of methotrexate. The donor received G-CSF at 10 micrograms/kg/day for 5 consecutive days and underwent leukapheresis on days 5 and 6. The neutrophil recovery to 500/microliter and platelet recovery to 20,000/microliter were day 12 and day 15, respectively. The patient is currently well with no GVHD or graft failure and a complete donor's chimerism.

Hematopoietic Stem Cell Transplantation↗
PubMed1997

[Preliminary screening for antiviral AIDS drugs. VIII. Report for fiscal year 1995].

Preliminary screening of antiviral AIDS drugs has been carried out using three different in vitro assay systems. Among 96 samples of different origin tested, two were shown to inhibit the growth of HIV in vitro. One of the positive samples (plant origin) has hopeful signs, as the ranges of effective doses are wider than those of most of positive samples which had been found by us.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Mechanism of resistance to NO-induced neurotoxicity in cultured rat dopaminergic neurons.

We previously reported that mesencephalic dopaminergic neurons are resistant to cytotoxicity induced by nitric oxide (NO). This study investigated the intracellular mechanism that protects dopaminergic neurons against NO toxicity in rat mesencephalic cultures. Peroxynitrite anion, an active metabolite of NO, caused significant cytotoxic effects against dopaminergic and nondopaminergic neurons, but NO caused cytotoxic effects restricted to nondopaminergic neurons. In addition, we studied the effects of ascorbate, an anti-oxidant, on NO-induced neurotoxicity against dopaminergic neurons and found that coadministration of ascorbate failed to affect resistance against NO-induced neurotoxicity. These findings suggest that the protecting mechanism from NO neurotoxicity in dopaminergic neurons is based on inhibition of conversion of NO to peroxynitrite anion, is independent of the NO redox state, and is possibly due to suppression of superoxide anion production. Furthermore, we investigated NO-induced neurotoxicity with or without pretreatment with sublethal doses of methylphenylpyridium ion (MPP+). Following pretreatment with 1 microM MPP+, which did not show significant cytotoxic effects against dopaminergic neurons, NO demonstrated significant cytotoxicity. Therefore, MPP+ may inhibit the protecting systems from NO neurotoxicity in dopaminergic neurons.

1-Methyl-4-phenylpyridinium↗
PubMed1996

Ontogeny of regulatory neuropeptides in the bullfrog taste organ.

During metamorphic stages (stages XX-XXV), the first appearance of nerve fibers containing substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP), galanin (GAL), and neuropeptide Y (NPY) in the bullfrog taste organs was different for each substance. CGRP fibers appeared first in association with the immature taste organs at stage XX. Up to stage XXV, the taste organs, epithelial disks, are close to their adult form, and SP, VIP and GAL fibers appeared within them. Throughout these stages, NPY fibers were absent, and no taste cells had immunoreactivity of the five neuropeptides. The present findings and previous physiological studies suggest that the immature taste organs in metamorphic stages already function as chemical and mechanical receptors and that these sensory mechanisms are under the control of peptidergic innervation.

Animals↗
PubMed1996

Discovery of a new tetrahydrobiopterin-synthesizing enzyme in the lemon mutant of the silkworm Bombyx mori.

A new tetrahydrobiopterin-synthesizing enzyme, which is different from sepiapterin reductase (EC 1.1.1.153), was discovered in the integument of the lemon mutant of the silkworm Bombyx mori. This enzyme converted 6-pyruvoyltetrahydropterin to tetrahydrobiopterin, an essential cofactor in the hydroxylation of aromatic amino acids, in the presence of NADPH. The reaction proceeded via 6-lactoyltetrahydropterin and 1'-hydroxy-2'-oxopropyltetrahydropterin as intermediates. The molecular mass of this enzyme was estimated to be 40 kDa. N-Acetylserotonin, a potent inhibitor of sepiapterin reductase, slightly inhibited the enzymatic reaction. In the presence of 0.5 mM N-acetylserotonin, the formation of tetrahydrobiopterin by sepiapterin reductase purified from the normal strain silkworm was completely inhibited. However, the formation of tetrahydrobiopterin by the enzyme purified from the lemon mutant was inhibited by only about 50%. These results suggest an alternative biosynthetic pathway to tetrahydrobiopterin.

Alcohol Oxidoreductases↗
PubMed1996

Precise coexistence of regulatory peptides in the nerve fibers of the amphibian carotid labyrinth demonstrated by a combination of double immunofluorescence labelling and a multiple dye filter.

An application of double-immunolabelling in combination with a multiple dye filter system demonstrated new findings regarding the distribution pattern of peptidergic fibers in the carotid labyrinth to addition to our previous findings shown by the individual filter system. In high magnification images of about 10% of the yellowish fibers which represent the coexistence of two neuropeptides, there was a definite difference in localization between the fluorescence originating from rhodamine (substance P fibers) and from FITC (vasoactive intestinal polypeptide and neuropeptide Y fibers), but it was clear that they are intertwined within a single nerve bundle. This combination method was able to discriminate two different peptidergic fibers which run side by side. The coexistence suggested previously by the individual filter system may actually be due to the phenomenon described above. This means that it is necessary to apply the multiple dye filter system for reliable evidence of coexistence of different two substances in a single nerve fiber.

Animals↗
PubMed1996

Ontogeny of the peptidergic fibers in the male mouse submandibular gland.

The first appearance of substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), galanin (GAL), leucine-enkephalin (1-ENK), and methionine-enkephalin (m-ENK) in the male mouse submandibular glands were different for each. VIP immunoreactive fibers first appeared on embryonic day 15 (E15), SP on E16, and CGRP fibers on E18. GAL, 1-ENK, and m-ENK fibers appeared in the early postnatal period, and NPY fibers occurred on postnatal day 21 (P21). From P0 to P21, VIP fibers rapidly increased in number, but SP and CGRP fibers increased only slightly. After P21, VIP, SP, and CGRP fibers decreased in number. ENK fibers were found only from P0 to P14. The number of these immunoreactive fibers in the adult phase was low in comparison with that in early postnatal phase. Around the blood vessels, SP, VIP, CGRP, NPY, and GAL fibers appeared by at least P7. These findings suggested that the transient high activity of VIP, CGRP, SP, and GAL and the transient appearance of ENKs in the nerve fibers may be related to the cell proliferation and differentiation of the functionally important structures of the mouse submandibular glands, and that the peptidergic innervation around the vasculature is probably involved in controlling local glandular circulation.

Animals↗
PubMed1996

Purification and properties of the 26S proteasome from the rat brain: evidence for its degradation of myelin basic protein in a ubiquitin-dependent manner.

A ubiquitin(Ub)/ATP-dependent proteolytic complex (26S proteasome) was highly purified from the rat brain. The brain 26S proteasome consisted of 22-110 kDa subunits characteristic of the typical 26S proteasome on the basis of SDS-PAGE. The two-dimensional PAGE (NEPHGE and SDS-PAGE) pattern revealed that the pI values and molecular masses of the brain 26S proteasome subunits were similar to those of the subunits of 26S proteasomes purified from the rat liver and skeletal muscles. The enzymatic properties of the brain 26S proteasome were similar to those of the liver complex and also to the Ub-conjugate degrading activity in the cerebral cortex extract. Furthermore, it was found that the brain 26S proteasome was capable of degrading the myelin basic protein in a Ub-dependent manner. These results indicate that the brain contains the Ub-conjugate-degrading 26S proteasome, the subunit composition of which appears similar to those of the other tissues, and that the myelin basic protein may be a candidate physiological substrate for the brain 26S proteasome.

Animals↗
PubMed1996

Localization, expression, and the role in fertilization of spermosin, an ascidian sperm trypsin-like protease.

In order to elucidate the role of spermosin (a novel sperm trypsin-like protease) in ascidian fertilization, we developed an antibody against the ascidian spermosin: the antibody appears specific to the spermosin but not to the acrosin. By Western blot analysis, spermosin was found to be expressed just before and during the spawning season. Immunocytochemical studies have shown that spermosin is localized on the sperm head. It was found that the spermosin was released from the sperm during the sperm reaction, and the anti-spermosin antibody, but not control antibody, inhibited the fertilization in a concentration-dependent manner. These results indicate that spermosin plays an essential role in ascidian fertilization.

Acrosin↗
PubMed1996

Altered intracellular Ca2+ regulation in pancreatic acinar cells from acute streptozotocin-induced diabetic rats.

We investigated intracellular Ca2+ regulation in pancreatic acinar cells from rats with diabetes induced by a single injection of streptozotocin (80 mg/kg). Experiments were performed 2 days and 7 days after the injection of streptozotocin. The density of muscarinic receptors, measured by [3H]N-methyl scopolamine binding, was unchanged in 2-day-diabetic rats, but was significantly increased in 7-day-diabetic rats. The percentage of high affinity receptors (RH) and low affinity receptors (RL) determined from the competitive curves with [3H]N-methyl scopolamine and carbachol was not change in 2-day-diabetic rats compared to controls, whereas 7-day-diabetic rats showed a decrease in %RH and an increase in %RL. The carbachol-evoked initial peak of intracellular Ca2+ concentration ([Ca2+]i) was increased in 2-day-diabetic rats and decreased in 7-day-diabetic rats, compared to controls. In the carbachol-induced sustained phase in [Ca2+]i, the response in 7-day-diabetic rats was significantly decreased; however, there was no difference between controls and 2-day-diabetic rats. Carbachol (100 microM)-induced [3H]inositol 1,3,4-trisphosphate generation was significantly lower in diabetic rats than in the controls. The addition of inositol 1,4,5-trisphosphate (1,4,5-IP3) significantly increased 45Ca2+ release from saponin-permeabilized cells in 2-day-diabetic rats, but did not do so in 7-day-diabetic rats. Ca2+ refilling into the intracellular stores, determined by second cholecystokinin-8 (10 nM) stimulation after 10 microM carbachol stimulation, was increased in 2-day-diabetic rats and decreased in 7-day-diabetic rats. These observations indicate that the alterations in intracellular Ca2+ regulation accompanied by changes in transmembrane signaling occur in the earlier stage of the diabetic state. The findings also suggest that the increase in the carbachol-evoked [Ca2+]i peak in 2-day-diabetic rats is related predominantly to the higher sensitivity of 1,4,5-IP3-sensitive Ca2+ stores and the increase in the capacity of Ca2+ refilling in these animals, whereas the reduction in the [Ca2+]i peak in 7-day-diabetic rats appears to be related to the essential decrease in receptor-mediated 1,4,5-IP3 generation and the decrease in Ca2+ refilling capacity.

Acute Disease↗
PubMed1996

Coexistence of nitric oxide synthase and neuropeptides in the mouse vomeronasal organ demonstrated by a combination of double immunofluorescence labeling and a multiple dye filter.

Nitric oxide synthase (NOS)-immunofluorescence techniques were applied to the mouse vomeronasal organ. Immunoreactivity for NOS was found in the nerve fibers distributed in the receptor-free epithelium, and around the blood vessels and glands in the cavernous tissue. No NOS fibers were seen in the receptor area. A combination of double immunofluorescence labeling and multiple dye filter revealed that a part of the substance P (SP)-immunoreactive nerve fibers in the cavernous tissue contained NOS and that all the vasoactive intestinal polypeptide (VIP)-immunoreactive nerve fibers around the blood vessels and glands in the cavernous tissue contained NOS. A few SP-immunoreactive cell bodies in the trigeminal ganglion showed coexistence with NOS, and almost all VIP-immunoreactive cell bodies in the sphenopalatine ganglion showed coexistence with NOS. Immunoreactivity for NOS without VIP in the cell bodies in the sphenopalatine ganglion was also found. These results suggest that NOS-immunoreactive nerve fibers in the mouse vomeronasal organ originate from the trigeminal and the sphenopalatine ganglia, and may modulate the vascular tone and the glandular secretion. In addition, these functions may be controlled in part by the interaction of nitric oxide and neuropeptides.

Animals↗
PubMed1996

Structure of a galactan from cell walls of Bifidobacterium catenulatum YIT4016.

A structural study was carried out on a galactose-rich polysaccharide fraction isolated from cell walls of Bifidobacterium catenulatum YIT4016 after N-acetylmuramidase digestion. The polysaccharide contained galactose and glucosamine in a molar ratio of 16.9:1.0. Data obtained by 13C NMR spectroscopy showed that the backbone chain of this polysaccharide is composed of galactofuranose residues, while the branches consist of galactopyranosyl residues. Furthermore, the data obtained from NaIO4 oxidation, partial methanolysis and methylation analysis indicated that this polysaccharide consists of a trisaccharide repeating unit having the following structure: [sequence: see text]

Bifidobacterium↗
PubMed1996

Different mechanisms of glutamate-induced neuronal death between dopaminergic and non-dopaminergic neurons in rat mesencephalic culture.

Parkinson's disease is characterized by dopaminergic neuronal degeneration, but its pathogenic mechanism is still unknown. In the dopaminergic neurons, oxygen radicals such as hydrogen peroxide are released through dopamine oxidation. Many factors are involved in radical formation, but glutamate and nitric oxide (NO) are the major effectors of the radical-induced neurotoxicity mediated primarily through calcium influx. In the cultured embryonic rat mesencephalon, we investigated the dopaminergic and non-dopaminergic neuronal death induced by glutamate and by NO-generating agents. Although glutamate had a neurotoxic effect on both dopaminergic and non-dopaminergic neurons, it showed slightly greater effect in the dopaminergic neurons. In contrast to glutamate, NO-generating agents (S-nitrosocysteine and sodium nitroprusside) showed neurotoxic effects restricted exclusively to non-dopaminergic neurons. Although N omega-nitro-L-arginine, and NO synthase inhibitor, had no significant effect on the glutamate-induced cytotoxicity in dopaminergic neurons, it had a significant antagonistic effect on that in non-dopaminergic neurons. These findings indicate the presence of two different mechanisms of glutamate-induced neuronal death, one being neurotoxicity not mediated by NO, found in dopaminergic neurons, and the other being that mediated via NO, found in non-dopaminergic neurons.

Analysis of Variance↗