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Biomedical subjects

T Ihara

Publications and source records attributed to T Ihara.

At least 55 records · Page 3Linked to original sources
PubMed1998

Expression and purification of biologically active porcine follicle-stimulating hormone in insect cells bearing a baculovirus vector.

Biologically active recombinant porcine FSH (rec-pFSH) free from the cognate pituitary glycoprotein hormone LH was produced. It was synthesized by a baculovirus vector-insect cell system using two cDNAs encoding the glycoprotein alpha and FSH beta subunits. Its antigenicity was the same as that of pFSH prepared from the pituitary. Glycosylation of rec-pFSH was shown by tunicamycin treatment but the molecular mass of each subunit was lower than that of pituitary-derived FSH, because of the absence of trimming of terminal sugars in insect cells. Rec-pFSH was secreted into the culture medium at about 1 mg/l and purified in six fractions, because of the heterogeneity of the sugar group, by S-Sepharose and concanavalin A-Sepharose column chromatography. The biological activity of rec-pFSH was examined by measuring its effect on progesterone secretion from porcine granulosa cells and germinal vesicle breakdown (GVBD) of porcine oocytes. It showed adequate activity with respect to progesterone secretion, although some fractions rich in the sugar group showed lower activity than that of pituitary-derived FSH. It exhibited higher GVBD activity than that of pituitary-derived FSH at concentrations as low as 1 ng/ml. These results demonstrate that the baculovirus vector-insect cell system can provide biologically active rec-pFSH.

Animals↗
PubMed1998

[The prevention of cytomegalovirus infection and disease by administration of biological products].

Symptomatic cytomegalovirus(CMV) infection is a serious complication in organ transplant and bone marrow transplant recipients. CMV immunoglobulin is available to prevent CMV disease in renal transplant and bone marrow transplant recipients, but not so efficacious in liver transplant and heart transplant recipients. Live CMV vaccine, Towne strain, is immunogenic in renal transplant recipients. Concerns about potential side effects of live-attenuated vaccine have stimulated the development of subunit vaccine. Several of CMV subunit vaccine are tested in animal models. Adoptive immunotherapy has been newly developed to prevent CMV disease in bone marrow transplant recipients. The suitable prevention for CMV infection and disease in accordance with the immunological status of transplant recipients will be established in the near future.

Animals↗
PubMed1998

[Fundamental and clinical studies on tazobactam/piperacillin in the pediatric field].

Pharmacokinetics, efficacy and safety of tazobactam/piperacillin (TAZ/PIPC), a new beta-lactamase inhibitor combined with a penicillin antibiotic, were studied in pediatrics and the following results were obtained. 1) Serum concentration and urinary excretion of TAZ/PIPC after intravenous administration at a dose of 46 mg/kg to one child were investigated. Serum half-lives were 0.5 hours for TAZ and 0.6 hours for PIPC, while the urinary recovery rates in the first 6 hours after administration, were 61.6% and 56.3% respectively. 2) TAZ/PIPC was administered at a dose of 46.0-73.5 mg/kg t.i.d. for 3-13 days to 10 patients, 6 with respiratory infection, 1 with pharyngotonsillitis, 1 with pertussis and 2 with soft tissue infection of skin. Clinical response were excellent in 5 cases and good in 5 cases, and the efficacy rate was 100%. Bacteriologically, 2 strains (Staphylococcus aureus and Streptococcus pyogenes) isolated from 2 patients were eradicated after the treatment. As for adverse reaction, mild skin rash was observed in 1 case but disappeared within 2 days after withdrawal of the drug. As for abnormal laboratory test results decrease in neutrophiles and increase in eosinophiles in each 1 case were observed, which were, however, normalized after administration. From the above results, tazobactam/piperacillin was considered to be a useful antibiotic in the pediatric field.

Bacterial Infections↗
PubMed1997

Tranilast inhibits contraction of rat aortic smooth muscle.

Recently, the anti-allergic drug tranilast has been shown to reduce the rate of coronary restenosis after percutaneous transluminal coronary angioplasty. In this study, we investigated the effect of tranilast on contraction of and Ca2+ movement in vascular smooth muscle. We measured the isometric force and fura-2-estimated intracellular Ca2+ concentrations ([Ca2+]i) of rat aortic strips. Exposure of aortic strips to tranilast (0-500 microM) dose-dependently inhibited endothelin-1-induced increases in tension and [Ca2+]i elevation of the strips. Similar inhibition by tranilast was observed in response to high K+ stimulation. These results suggest that tranilast inhibits the contraction of vascular smooth muscle by inhibiting Ca2+ mobilization, which might be related to its preventive effect on coronary restenosis after percutaneous transluminal coronary angioplasty.

Animals↗
PubMed1997

Baculovirus-insect cell production of bioactive porcine FSH.

The in vitro and in vivo bioactivity of recombinant porcine FSH (rpFSH) produced from insect cells through use of a baculovirus expression system were studied and compared with those of natural FSH preparations. Determination of in vitro bioactivity, using the rat Sertoli cell aromatase bioassay, indicated that rpFSH is as active as purified pituitary FSH. Determination of in vivo bioactivity, using the mouse uterine weight bioassay, indicated that rpFSH is as active as purified pituitary FSH. Using the mouse Leydig cell testosterone bioassay, it was demonstrated that the intrinsic LH bioactivity of rpFSH is negligible. The increases in ovarian and uterine weight, and the stimulation in follicular growth in immature hypophysectomized rats induced by rpFSH supplemented with hCG were comparable to those induced by natural FSH preparations. Furthermore, rpFSH alone in hypophysectomized mice stimulated preantral follicular growth to preovulatory stages, and the subsequent injection of hCG caused ovulation. These results demonstrate that in vitro and in vivo biological characteristics of rpFSH produced from baculovirus-insect cells are indistinguishable from those of FSH isolated from natural sources.

Journal Article↗
PubMed1997

Apoptotic cellular damage in mice after T-2 toxin-induced acute toxicosis.

By histopathologic, electron microscopic, and immunochemical observation, the mechanism of cellular death was investigated in thymus, spleen, and liver of mice given intraperitoneally sublethal doses of T-2 toxin, a trichothecene mycotoxin. In the thymus and spleen of mice given 5.0 mg/kg body weight of T-2 toxin and killed 12 hours later, a massive cellular destruction characterized by chromatin condensation was evident, and electron microscopy analysis revealed the presence of apoptotic bodies. In the liver of mice given 2.5 mg/kg of T-2 toxin and killed 2 hours later, the induction of apoptotic cellular lesions was observed by electron microscopy, and Kupffer cells phagocytosed the apoptotic bodies. Such lesions were not observed in the mice killed 12 hours after receiving the toxin. In situ nick translation analysis (Tunel method) revealed DNA fragmentation in thymus, spleen, and liver shortly after administration of T-2 toxin. As previously observed in vitro, these findings indicated that T-2 toxin is a potent inducer of apoptotic cell death in thymus, spleen, and liver in vivo; especially in liver, apoptosis is induced rapidly as compared with the other tissues observed, and Kupffer cells play an important role for clearance of apoptosis.

Animals↗
PubMed1997

Acute lupus peritonitis successfully treated with steroid pulse therapy.

A 21-year-old man with systemic lupus erythematosus (SLE) who developed acute lupus peritonitis is described. Acute lupus peritonitis appeared during generalized lupus flare, with nausea, vomiting, frequent diarrhea, and abdominal tenderness with rebound and guarding. The patient was afebrile and had decreased bowel sounds. Abdominal ultrasonography and computed tomography revealed marked thickening of the gastric, duodenal, and jejunal walls, massive intraluminal fluid collection, and increasing ascites. Gastrointestinal endoscopy showed edematous mucosa with multiple erosions of the stomach and duodenum. The ascitic fluid was remarkable for low complement levels and elevated anti-DNA antibody. These manifestations of acute lupus peritonitis resolved after steroid pulse therapy with methylprednisolone. We should consider acute lupus peritonitis in a patient with SLE when abdominal symptoms are severe. Experience with our patient indicates that steroid pulse therapy is effective for this rare but severe manifestation of SLE.

Acute Disease↗
PubMed1997

Tranilast inhibits contraction and Ca2+ movement of porcine coronary arteries.

In a recent clinical study, tranilast, an anti-allergic agent, was shown to reduce the rate of coronary restenosis after percutaneous transluminal coronary angioplasty, although the mechanism of this effect is unclear. The present study was undertaken to investigate the effects of tranilast on contraction and Ca2+ movement of the coronary arteries. We characterized the effects of tranilast on isometric force and aequorin-estimated intracellular Ca2+ concentrations ([Ca2+]i) of porcine coronary artery strips. Tranilast concentration-dependently (10-500 microM) inhibited histamine (3 x 10(-5) M)-induced contraction of the coronary arteries. A similar tendency was observed in the response to high K+ (30 mM) stimulation. Histamine caused phasic and tonic increases in [Ca2+]i, and high K+ caused a tonic increase in [Ca2+]i of smooth muscle, both of which were significantly suppressed in the presence of tranilast. These results suggest that tranilast inhibits the contraction of coronary arteries by inhibiting both Ca2+ influx from extracellular environment and Ca2+ release from intracellular Ca2+ stores, which might be related to its preventive effect on restenosis after coronary angioplasty.

Animals↗
PubMed1997

Measles virus induces apoptotic cell death in lymphocytes activated with phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore.

Peripheral blood mononuclear cells (PBMC) and T lymphocytes were infected with measles virus (MV) and cultured with a protein kinase C (PKC) activator, PMA and a calcium ionophore, ionomycin. After stimulation, cell viability and incorporation of 5-bromo-2'- deoxyuridine (BrdU) were decreased in MV-infected cells compared with mock-infected cells. DNA content analysis and terminal deoxytransferase (TdT)-mediated dUTP nick end labelling demonstrated that the hypodiploid fraction and DNA fragmentation were increased in MV-infected, T lymphocytes activated with PMA plus ionomycin. These data suggest that MV induces apoptotic cell death in cells activated by PMA plus ionomycin. In contrast to stimulation with PMA plus ionomycin, mitogenic stimulation with phytohaemagglutinin (PHA) did not induce apoptotic cell death in MV-infected cells, although cell proliferation was suppressed. Apoptosis induced in stimulated, MV-infected cells may be one mechanism of immunosuppression.

Adult↗
PubMed1997

Behavior of Na+/K(+)-ATPase alpha-subunit alleles in sea urchin eggs upon fertilization.

The allelic division of the Na+/K(+)-ATPase alpha-subunit gene was found in eggs of the sea urchin Hemicentrotus pulcherrimus by polymerase chain reaction (PCR). Two PCR products of different lengths were detected from a genome in one embryo derived from a fertilized egg, although only one product in one embryo derived from an artificially activated egg by parthenogenesis was detected, indicating one copy of the gene in a haploid genome. One of the two PCR products from each fertilized egg was identical in size to the product from an artificially activated egg in the same batch. The other PCR product was the same in length as one of the products from the sperm with which the eggs were fertilized. These results indicate that recombination of the heteromeric alleles of the Na+/K(+)-ATPase alpha-subunit gene occurs in the sea urchin egg due to meiosis and fertilization. The sequencing of these products demonstrated that their exon sequences were identical and that the intron, inserted in the PCR products, generated polymorphism in length due to the frequency of the repeating 53 bp sequence and insertion/deletion of other two segments.

Alleles↗
PubMed1997

Ultrastructural study of antral G cells in patients with duodenal ulcer: effect of Helicobacter pylori eradication.

BACKGROUND: It is established now that Helicobacter pylori infection is associated with exaggerated gastrin release to meals and other stimuli and that the abnormal secretion of gastrin is reversed after successful treatment of the infection. By comparing morphology of G cells from the same patients before and after treatment, we were able to investigate the ultrastructural effect of cure of H. pylori on G cells. METHODS: Gastric mucosal biopsy specimens were obtained from 10 patients with duodenal ulcer before and 3, 6, and 9 months after cure of H. pylori infection. Negative controls consisted of four healthy volunteers without H. pylori infection. G cells were evaluated by immunohistochemical and electron microscopy. Treatment with H2-antagonists was continued for 6 months after cure of the H. pylori infection. RESULTS: Ultrastructural studies of secretory granules of antral G cells in controls displayed a broad range of electron density ranging from dark with a full appearance to totally electron-lucent with a "vacuolating" appearance. In duodenal ulcer patients before treatment, electron-lucent vacuolating granules predominated. After elimination of H. pylori, G-cell granules showed a marked increase in electron density close to that of controls. CONCLUSIONS: Our study showed that the density of granules of G cells is decreased in H. pylori-infected duodenal ulcer patients compared to that in H. pylori-negative controls and is consistent with enhanced gastrin release. Cure of H. pylori infection was associated with return to normal density of G-cell granules.

Anti-Bacterial Agents↗
PubMed1997

Two types of Na+/K(+)-ATPase alpha subunit gene transcript in embryos of the sea urchin, Hemicentrotus pulcherrimus.

We have characterized the nucleotide sequence of Na+/K(+)-ATPase alpha subunit (NKA) cDNA in embryos of the sea urchin, Hemicentrotus pulcherrimus. The primer extension experiments showed that the sea urchin NKA gene generated multiple lengths of transcript. To obtain the 5'-ends of the transcripts, we isolated cDNA clones by the rapid amplification of cDNA ends (RACE). These clones were classified into 2 types on the basis of their 5' leader sequences. The sequences of the clones were identical except their 5' leaders. By Northern blot analysis, 1 of the 2 types of transcripts was always detectable in sea urchin embryos during early development, and another was not detected before the morula stage. Genomic PCR demonstrated that the two 5' leaders were coded by different exons separated by an intron in a single gene. These results show that the transcripts coding 2 isoforms were expressed from a single gene.

Animals↗