Biomedical subjects

M Yoshida

Publications and source records attributed to M Yoshida.

At least 775 records · Page 43Linked to original sources

PubMed1998

Expression of aggression attenuates both stress-induced gastric ulcer formation and increases in noradrenaline release in the rat amygdala assessed by intracerebral microdialysis.

The effects of an aggressive biting response on stress-induced noradrenaline (NA) release in the rat amygdala and gastric ulcer formation were studied with an intracerebral microdialysis technique. Rats were exposed to a 60-min period of cold restraint stress with or without being allowed to bite a wooden stick. They were sacrificed 100 min after release from stress to investigate gastric ulcer formation. Cold-restraint stress increased NA release to 304 +/- 22.3 and 206 +/- 23.8% of basal levels (mean +/- SEM) in the nonbiting and biting groups, respectively. The stress-induced increases in NA release in the nonbiting group were significantly higher than those in the biting group. In the nonbiting group, significant increases in NA release continued for 80 min after release from stress; however, NA levels in the biting group recovered to basal levels immediately after the cessation of stress. Although many severe gastric lesions with bleeding were found in the nonbiting group, fewer gastric lesions without bleeding were found in the biting group. The cumulative length of gastric lesions in the nonbiting group and in the biting group was 26.2 +/- 7.4 and 6.8 +/- 3.9 mm (mean +/- SEM), respectively. The mean number of ulcers in the nonbiting group and the biting group was 11.8 +/- 1.3 and 1.8 +/- 0.7 (mean +/- SEM), respectively. Both the cumulative length of ulcers and the number of ulcers were significantly lower than those seen in the nonbiting group. These findings strongly suggest that expression of aggression during stress exposure attenuates not only stress-induced increases in NA release in the rat amygdala but also gastric ulcer formation consequent to stress.

Aggression↗

PubMed1998

Verification of flow cytometorically-sorted X- and Y-bearing porcine spermatozoa and reanalysis of spermatozoa for DNA content using the fluorescence in situ hybridization (FISH) technique.

Flow cytometric sperm sorting based on X and Y sperm DNA difference has been established as the only effective method for sexing the spermatozoa of mammals. The standard method for verifying the purity of sorted X and Y spermatozoa has been to reanalyze sorted sperm aliquots. We verified the purity of flow-sorted porcine X and Y spermatozoa and accuracy of DNA reanalysis by fluorescence in situ hybridization (FISH) using chromosome Y and 1 DNA probe. Eight ejaculates from 4 boars were sorted according to the Beltsville Sperm Sexing method. Porcine chromosome Y- and chromosome 1-specific DNA probes were used on sorted sperm populations in combination with FISH. Aliquots of the sorted sperm samples were reanalyzed for DNA content by flow cytometry. The purity of the sorted X-bearing spermatozoa was 87.4% for FISH and 87.0% for flow cytometric reanalysis; purity for the sorted Y-bearing spermatozoa was 85.9% for FISH and 84.8% for flow cytometric reanalysis. A total of 4,424 X sperm cells and 4,256 Y sperm cells was examined by FISH across the 8 ejaculates. For flow cytometry, 5,000 sorted X spermatozoa and 5,000 Y spermatozoa were reanalyzed for DNA content for each ejaculate. These results confirm the high purity of flow sorted porcine X and Y sperm cells and the validity of reanalysis of DNA in determining the proportions of X- and Y-sorted spermatozoa from viewing thousands of individual sperm chromosomes directly using FISH.

Animals↗

PubMed1998

Development of a dot blot neutralizing assay for HHV-6 and HHV-7 using specific monoclonal antibodies.

To elucidate further immune responses to human herpesviruses 6 and 7 (HHV-6 and -7), a neutralizing antibody assay was established for these viruses using a dot blot method. Three monoclonal antibodies against HHV-6 and 12 monoclonal antibodies against HHV-7 were developed and characterized by radio-immunoprecipitation. One monoclonal antibody which recognizes the 135 kDa late polypeptide of HHV-6 and several which recognize the 125 kDa late polypeptide of HHV-7 were selected to monitor virus growth by a dot blot antigen-detection method. The dot blot method was then used for the assay of HHV-6 and -7 neutralizing antibodies in human serum samples. The neutralization endpoints determined by the dot blot were comparable to those determined by immunofluorescence (IF). The neutralizing antibody titers appeared to correlate with the antibody titers determined by the indirect IF antibody test. The dot blot neutralization assay is easy to perform, is highly reproducible and objective when compared with the conventional methods based on cytopathology or IF for determining neutralization endpoints.

Animals↗

PubMed1998

Comparison of antiviral compounds against human herpesvirus 6 and 7.

Four classes of antiviral compounds were evaluated for inhibitory activity against two variants of human herpesvirus 6 (HHV-6A and -6B) and human herpesvirus 7 (HHV-7). These included: (1) a pyrophosphate analog, phosphonoformic acid (PFA); (2) beta-guanine analogs, 9-(2-hydroxyethoxymethyl)guanine (acyclovir or ACV), 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine (ganciclovir or GCV) and 9-(4-hydroxy-3-hydroxy-3-hydroxymethylbutylyl)guanine (penciclovir or PCV); (3) acyclic nucleoside phosphonates, (S)-1-[(3-hydroxy-2-phosphonylmethoxy)propyl]cytosine [cidofovir or (S)-HPMPC] and its cyclic derivative (S)-cyclic-HPMPC (cHPMPC), 9-[[2-hydroxy-1-phosphonomethoxy)ethoxy]methyl]guanine (HPMEMG) and 9-[(2-phosphonylmethoxy)ethyl]-2,6-diaminopurine (PMEDAP), and the seven other related compounds; and (4) a series of benzimidazole ribonucleosides, including 2-bromo-5,6-dichloro-1-(beta-D-ribofuranosyl)benzimidazole (BDCRB). End-point inhibitory concentration (EPC) and 50% effective inhibitory concentration (EC50) values were determined by a dot-blot antigen detection method in cord blood mononuclear cells infected with HHV-6A, HHV-6B or HHV-7 at a multiplicity of infection of 0.004 CCID50/cell. (S)-HPMPC and cHPMPC had an EC50 value of approximately 0.3 microg/ml for HHV-6A, 1.2 microg/ml for HHV-6B and 3.0 microg/ml for HHV-7. These compounds were the most active of those tested against each virus. The EC50 value of GCV for HHV-6A was 0.65 microg/ml, 1.33 microg/ml for HHV-6B, and >7 microg/ml for HHV-7. The EC50 values of ACV and PCV were approximately 6-8 microg/ml for HHV-6A, 16-24 microg/ml for HHV-6B and 121-128 microg/ml for HHV-7. These drugs were the least active. The sensitivity of HHV-7 to the guanine analogs was different from HHV-6, suggesting a difference in selectivity of specific viral enzymes.

Antiviral Agents↗

PubMed1998

Amelioration of neurovascular deficits in diabetic rats by a novel aldose reductase inhibitor, GP-1447: minor contribution of nitric oxide.

The effects of a novel potent aldose reductase inhibitor, GP-1447 [3-[(4,5,7-trifluorobenzothiazol-2-yl)methyl]-5-methylphenylace tic acid] on the sciatic nerve blood flow in streptozotocin-induced diabetic rats were examined. Blood flow was analyzed in terms of mass, i.e. the volume of blood in tissue, and of velocity, i.e. the velocity of the blood flow. In diabetic rats, a 63% decrease in blood flow due to a decrease in velocity was observed. The blood mass in the same animals fluctuated, thereby increasing its range of values. Treatment with GP-1447 at a dose of 30 mg/kg per day for 4 consecutive weeks following a 3-week period without treatment ameliorated the reduced blood flow by 51%, and was accompanied by a recovery of velocity. The increase in the range of blood mass values was reversed by treatment with GP-1447. The restoration of the range of blood mass values, but not that of the blood flow, by GP-1447 was blocked by treatment with the nitric oxide (NO) synthase inhibitor, NG-nitro-L-arginine. Motor nerve conduction velocity (MCV) changes in parallel with blood flow values, while it is inversely proportionate to alterations in the range of blood mass values. It is suggested that the observed beneficial effect of GP-1447 on blood flow is involved in the restoration of decreased MCV in diabetes. It would appear that GP-1447-induced amelioration of neurovascular defects is not mediated solely by the improvement of the NO system.

Aldehyde Reductase↗

PubMed1998

Development of vanadate sensitive human erythrocytes insulin receptor tyrosine phosphatase assay.

The aim of this study was to investigate the effect of sodium orthovanadate on the alterations of human erythrocytes insulin receptor autophosphorylation. Human erythrocytes were incubated with insulin in a cell system and then lysed. The autophosphorylated insulin receptors were measured with the aid of a two-site immunofluorometric assay and using a monoclonal anti-insulin receptor antibody to label the insulin receptors and a monoclonal anti-phosphotyrosine antibody to assess tyrosine phosphorylation. When the erythrocytes were treated with insulin and then reincubated in insulin-free medium, vanadate completely inhibited insulin receptor dephosphorylation, although it had no effect on in vitro receptor autophosphorylation. Thus insulin receptor tyrosine phosphatase activity is postulated to be [% (autophosphorylated insulin receptors with vanadate - autophosphorylated insulin receptors without vanadate)/total insulin receptors] under overall steady conditions in a cell system. Using this assay, the insulin receptor tyrosine phosphatase activities of 25 control and 32 diabetic subjects were studied. There was no significant difference in insulin receptor tyrosine phosphatase activity between control subjects and diabetic subjects (0.173 +/- 0.062 vs 0.209 - +/- 0.057 autophosphorylated insulin receptors units/insulin receptors units). The assay used in this study requires only 0.6 ml of whole blood, and so should be a useful tool for detecting patients who are insulin-resistant due to abnormal insulin receptor tyrosine phosphatase activity.

Animals↗

PubMed1998

A comparison between magnetic resonance imaging and pathologic findings in patients with disc displacement.

PURPOSE: This study compared the magnetic resonance imaging (MRI) and pathologic findings in patients with disc displacement without perforation. PATIENTS AND METHODS: Eleven patients and 30 asymptomatic volunteers underwent MRI using the three-dimensional (3D) fast imaging with a steady precession sequence (FISP) acquisition technique. The 11 patients (11 joints) then underwent discectomy, and the pathologic and MRI findings were compared. RESULTS: MRI (FISP-3D) examination of the temporomandibular joint in 11 patients (11 joints) showed low signal intensity in the anterior band and the intermediate zone of the disc, and high signal intensity in the posterior band of the disc and retrodiscal tissue. On microscopic examination, the anterior band and intermediate zone of the disc were found to consist of dense collagenous bundles showing mild hyaline degeneration. Myxomatous degeneration was seen in the posterior band of the disc (11 joints), and edematous change was seen in the retrodiscal tissues (seven joints). CONCLUSIONS: Pathologic changes in the disc and the retrodiscal tissues are accurately depicted by FISP-3D.

Adult↗

PubMed1998

Identification of 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) and 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone (HEMF) with DNA breaking activity in soy sauce.

Components with DNA breaking activity in soy sauce were investigated. It was found that there were water soluble high molecular weight DNA breaking components in soy sauce. Two DNA breaking components in the ethyl acetate extract of soy sauce were identified as fragrant components, 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) and 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone (HEMF), in addition to the previously characterized DNA breaking fragrant component 4-hydroxy-5-methyl-3(2H)-furanone (HMF) (Hiramoto et al., 1996b). Characterization of DNA breaking activity of HEMF was performed, and the mechanisms for the breaking were considered. HEMF cleaved the single strands of supercoiled pBR 322 DNA at pH 7.4 dose dependently and time dependently. DNA breaking was inhibited by superoxide dismutase, catalase, hydroxyl radical scavengers, spin trapping agents and metal chelators, and enhanced by Fe(III) ion. Electron spin resonance-spin trapping technique revealed the generation of hydroxyl radical. Hence, active oxygen species derived from interaction of HEMF with metal ions and oxygen participated in the cleavage. HEMF exhibited mutagenicity to Salmonella typhimurium TA100 without metabolic activation and induced micronucleated mouse peripheral reticulocytes.

Animals↗

PubMed1998

Ovarian dysgerminoma showing high serum levels and positive immunostaining of placental alkaline phosphatase and neuron-specific enolase associated with elevation of serum prolactin level.

We report a 35-year-old Japanese female patient with ovarian dysgerminoma showing elevated serum levels of placental alkaline phosphatase (PLAP), neuron-specific enolase (NSE) and prolactin (PRL). All elevated tumor markers improved dramatically after the removal of the tumor. Immunohistochemically examined, the tumor was stained positive for PLAP and NSE and negative for PRL. Our present case is the first report of dysgerminoma showing positive immunostaining for PLAP and NSE, and the association of high serum level of PRL followed by decrease accompanied by the tumor debulking.

Adult↗

PubMed1998

Central administration of interleukin-1 beta reduces natural killer cell activity in non-pregnant rats, but not in pregnant rats.

To examine responses of natural killer cell activity (NKCA) to interleukin-1 beta (IL-1 beta) during pregnancy, we determined splenic NKCA as well as blood and brain indicators in virgin and pregnant rats (14 or 21 days gestation) with intracerebroventricular (i.c.v.) administration of IL-1 beta. NKCA was reduced and blood beta-endorphin (beta EP) was increased with the progress of pregnancy. I.c.v. administration of IL-1 beta reduced NKCA and corticotropin-releasing hormone (CRH) in the median eminence (ME), and increased beta EP in virgin rats, but did not change any parameters in pregnant rats with 21 days gestation. These data suggest that the immunosuppressive effect of central administration of IL-1 beta is blocked by pregnancy. CRH in the ME and opioid system seem to be involved in the inhibitory effect of pregnancy on IL-1 beta-induced immunosuppression.

Animals↗

PubMed1998

Surgical treatment for transvenous tumor extension into the heart: four cases.

From 1984 to 1996, four patients with transvenous intracardiac tumor extension underwent operations in the Kobe University Hospital. The primary tumors of two were intravenous leiomyomatoses originating from the uterus; a third patient had invasive thymoma, and the fourth patient had clear cell sarcoma of the kidney. In 1985, one patient had a curative, staged resection. One-stage operations were carried out in three patients, and all intracardiac tumors were successfully resected en bloc with the primary tumors under conditions of electrical ventricular fibrillation and mild hypothermia. Combined venous reconstructions were necessary for en bloc resection in three cases. Two patients with malignancy received postoperative chemoradiotherapy, and all four patients were discharged uneventfully from our hospital. We consider radical resection with curative intent only for patients with tumors extending into the heart. In these cases, a one-stage operation is preferable, and electrical ventricular fibrillation with mild hypothermia is a recommended method of circulatory assist because of its simplicity.

Adult↗

PubMed1998

Strain-differences in proliferative activity of uterine endometrial cells in Donryu and Fischer 344 rats.

Strain differences in proliferative activities of uterine endometrial cells were sequentially investigated in Donryu and Fischer 344 (F344) rats until 52 weeks of age. At 13 and 26 weeks of age, when all rats showed a normal estrous cycle, histological findings for the endometrium at each estrous stage were similar in both strains. Mitoses of epithelial cells were frequently observed during the proestrous and metestrous stages, and especially in the latter, but were very few in the estrous stage. The bromodeoxyuridine(BrdU)-labeling indices coincided with the histological findings, the results indicating a peak of cell proliferative activity in the metestrous stage. In Donryu rats, estrous cycle abnormalities increased age-dependently after 26 weeks of age, and almost all animals showed persistent estrus at 52 weeks of age. At 39 and 52 weeks of age, the rats showing persistent estrus displayed similar vaginal smears and histological findings to those of younger rats in the estrous stage, but the BrdU-labeling indices of epithelial cells were age-dependently increased. In contrast, vaginal smear of F344 rats indicated a normal estrous cycle at all ages, with no changes in BrdU-labeling being observed. Previously, we reported that the Donryu rat is a high incidence strain in terms of spontaneous development of endometrial adenocarcinomas, this being related to an age-dependent hormonal imbalance, characterized in particular by an increased estrogen/progesterone ratio. The F344 rat in contrast is a low incidence strain. The present results thus indicate that a constant high-level of proliferative activity of epithelial cells may play an important role, together with an age-related hormonal imbalance, in the spontaneous development of endometrial carcinomas in Donryu rats.

Adenocarcinoma↗

PubMed1998

Eicosanoid profile in cultured human pulmonary artery smooth muscle cells treated with IL-1 beta and TNF alpha.

Interleukin-1beta (IL-1beta) and tumor necrosis factor (TNF alpha) induce prostanoid biosynthesis in vascular smooth muscle cells by promoting cyclooxygenase (COX) expression, but little is known about the biosynthesis of lipoxygenase (LPO) metabolites. We investigated the effects of human recombinant IL-1beta and TNF alpha on the production of arachidonic acid (AA) metabolites by high-performance liquid chromatography (HPLC). After being labelled with 3H-AA, cultured human pulmonary artery smooth muscle cells (HPASMC) were incubated with or without IL-1beta (200 U/ml) and TNF alpha (500 U/ml). The arachidonic acid metabolites released from HPASMC were then analysed by HPLC. In control HPASMC, 6-keto-PGF1alpha and PGE2 were the principal metabolites of the COX pathway, while 5-HETE, LTC4 and D4 were the main products of the LPO pathway. HPASMC treated with 200 U/ml of IL-1beta and 500 U/ml of TNF alpha produced more COX metabolites such as 6-keto-PGF1alpha, thromboxane B2, PGF2alpha and PGE2 than control cells. Significant increases in the production of LPO derivatives such as LTB4, C4, D4, and 15-HETE were also found in IL-1beta-treated HPASMC. Although the release of LPO products tended to increase in TNF alpha-treated cells, no significant change was noted. Many AA metabolites including LTB4 are responsible for the inflammatory process in vivo. AA metabolites produced by pulmonary artery smooth muscle cells might play important roles in cytokine-mediated acute lung injury and inflammation.

6-Ketoprostaglandin F1 alpha↗

PubMed1998

Effects of thromboxane A2 antagonist on airway hyperresponsiveness, exhaled nitric oxide, and induced sputum eosinophils in asthmatics.

We examined effects of a thromboxane A2 (TXA2) antagonist seratrodast on airway hyperresponsiveness, exhaled nitric oxide (NO), and eosinophils in induced sputum in 14 asthmatics. Subjects were administered 80 mg of seratrodast once a day for 4 weeks. Respiratory conductance (Grs) was measured by the forced oscillation method and airway responsiveness was evaluated as the inhaled dose of methacholine, which induced 35% decrease in Grs. Subjects breathed into a Teflon bag, and NO concentration in the bag was measured by a chemiluminescence analyzer. Induced sputum comprised the entire expectorate produced during a 20 min inhalation of 3% saline, and was analyzed for total and differential cell counts. Airway hyperresponsiveness was significantly decreased by seratrodast. By contrast, no differences in either exhaled NO or percentage of eosinophils in sputum were observed before or after seratrodast. We conclude that seratrodast may attenuate airway hyperresponsiveness, presumably by antagonizing TXA2 released from the inflamed airways.

Anti-Asthmatic Agents↗

PubMed1998

Steroid hormones and their receptors in the brain.

Steroid hormones regulate several important functions of the brain by altering the expression of particular genes through their receptors. First in this paper the localization of glucocorticoid receptor immunoreactivity and mRNA in the brain was examined. Second biphasic effects of glucocorticoid on the hippocampus was described and particular emphasis was given on the apoptosis. Third the significance of estrogen receptor in the sexually dimorphic areas was discussed. These results suggest that steroids modulate the gene expression along with the alteration of cell structures in a different manner in a tissue-specific pattern.

Animals↗

PubMed1998

Synthesis of sialyl Lewis X pentasaccharide analogue for high-throughput screening of selectin blockers.

We have developed an effective synthesis of sLe(x) pentasaccharide glycolipid analogue 2. As a part of application of sLe(x) pentasaccharide glycolipid 2 synthesized here, we have investigated the construction of a high-through-put screening system for discovery of selectin blockers. As a result, it was found that compound 2 was a useful ligand for in vitro ELISA assay and could be an important material for high-throughput screening of selectin blockers.

Carbohydrate Conformation↗

PubMed1998

Electroencephalogram abnormality and high-dose busulfan in conditioning regimens for stem cell transplantation.

High-dose busulfan (BU) is widely used in combined chemotherapy before allogeneic or autologous bone marrow transplantation. Convulsions are reported as a side-effect of high-dose BU. We recorded electroencephalograms (EEGs) before and on the third day of BU administration in 22 patients. Abnormal EEGs were observed on the third day in 13 cases (59%). These patients were older (P < 0.05) and had had larger doses of BU (P < 0.025) than the nine patients with normal EEGs. Convulsions occurred in two of the 22 patients, one of whom was receiving prophylaxis with phenytoin. Gamma aminobutyric acid (GABA), a natural mediator of defense against epileptic activity, concentrations in cerebrospinal fluid measured before and after administration of BU showed no definite changes.

Adolescent↗

PubMed1998

Expression of Bcl-2 family of proteins in fresh myeloma cells.

Members of the Bcl-2 family of proteins, Bcl-2, Bcl-X(L), Bcl-Xs and Bax, are considered to play important roles in the regulation of apoptosis and drug resistance. To understand the significance of these proteins in fresh human myeloma cells, expression of Bcl-2 family of proteins was analyzed by Western blotting in 17 cases with multiple myeloma (MM) and three cases with plasma cell leukemia (PCL). Bcl-2 and Bcl-X(L) were found in 12 and nine samples, respectively. All PCL cases showed co-expression of Bcl-2 and Bcl-X(L). Analysis of MM cases showed that Bcl-2 was preferentially expressed in samples from cases with early clinical stage while Bcl-X(L) tended to be expressed in samples from cases at advanced clinical stage. Bcl-X(L) was significantly expressed in tumor cells from cases with extramedullar lesions. There was no correlation between the expression levels of Bcl-2 or Bcl-X(L) and preceding chemotherapy. Expression of Bax was found in only one patient who had pleural effusion caused by invasion of myeloma cells and a high serum LDH level. Survival analysis revealed that there was no statistical significance in expression of Bcl-2 or Bcl-X(L) although Bcl-X(L) tended to be expressed in cases with poor prognosis. These findings indicate that expression of Bcl-2 family of proteins is heterogeneously regulated in fresh myeloma cells. Expression of Bcl-X(L) and Bcl-2 may correlate with extramedullar invasion and early stage of the disease, respectively. Absence of Bax in myeloma cells may contribute to low sensitivity of myeloma cells to anti-cancer agents since Bax is reported to mediate cytotoxicity of some anti-cancer drugs.

Adult↗