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Biomedical subjects

S Oka

Publications and source records attributed to S Oka.

At least 109 records · Page 6Linked to original sources
PubMed2000

Interleukin-1alpha-dependent regulation of matrix metalloproteinase-9(MMP-9) secretion and activation in the epithelial cells of odontogenic jaw cysts.

Interleukin-1alpha (IL-1alpha) and matrix metalloproteinase-9 (MMP-9) are thought to be involved in odontogenic cyst expansion. In this study, we investigated the effects of IL-1alpha on the secretion and activation of MMP-9 in odontogenic jaw cysts. An active form of MMP-9 was present in odontogenic keratocyst (6 of 8 cases) fluids more frequently than dentigerous cyst (3 of 10 cases) and radicular cyst (3 of 10 cases) fluids, although proMMP-9 was present in all cyst fluids. Odontogenic keratocyst fragments in explant culture secreted a larger amount of IL-1alpha than dentigerous cyst and radicular cyst fragments in explant culture, and spontaneously secreted both proMMP-9 and an active form of MMP-9. The fragments of dentigerous cysts and radicular cysts secreted a small amount of proMMP-9, but no active form of MMP-9. Exogenously added recombinant human IL-1alpha (rhlL-1alpha) increased the secretion and activation of proMMP-9 in the fragments of dentigerous cysts and radicular cysts. The epithelial cells isolated from odontogenic keratocysts secreted IL-1alpha and proMMP-9 without stimulation. Under the cultivation on a fibronectin-coated dish, rhIL-1alpha increased the secretion of proMMP-9 from the epithelial cells in a dose-dependent manner. Moreover, rhIL-1alpha induced the secretion of proMMP-3 and plasminogen activator urokinase (u-PA) from the epithelial cells, and converted the secreted proMMP-3 to the active form in the presence of plasminogen. The secreted proMMP-9 was also activated in the presence of rhIL-1alpha and plasminogen. Hence, our results suggest that IL-1alpha may up-regulate not only proMMP-9 secretion but also proMMP-9 activation by inducing proMMP-3 and u-PA production in the cyst epithelial cells by autocrine/paracrine regulatory mechanisms.

Autocrine Communication↗
PubMed2000

[Acute surgical and endovascular therapy for stroke: especially patients with brain infarction].

From January 1994 to December 1997, 845 patients with stroke were admitted to Hakodate Municipal Hospital. They consisted of 514 patients with brain infarction, 206 with brain hemorrhage, 121 with subarachnoid hemorrhage and 4 with intracranial hemorrhage from arteriovenous malformation. The clinical categories of brain infarction were as follows; atherothrombotic recognized in 158 patients, cardioembolic in 114, lacunar in 217 and other categories in 25. With regard to the cures of brain infarction in the acute phase, direct percutaneous transluminal angioplasty (direct PTA) was carried out on three patients with atherothrombotic infarction, immediate PTA on two, superselective fibrinolytic therapy on two, and STA-MCA anastomosis on three. In all, ten atherothrombotic patients (6.3%) were treated by acute surgical or endovascular therapy. On the other hand, superselective fibrinolytic therapy was carried out on 35 patients (30.7%) with cardioembolic infarction. There were no patients in the lacunar infarction group who were given acute surgical treatment. Neurological improvement after 24 hours was recognized in 4 patients (40%) of 10 with atherothrombotic infarction, and in 9 patients (25.7%) of 35 with cardioembolic infarction. However, symptomatic intracerebral hematoma was recognized in 4 patients (11.4%) with cardioembolic infarction. Indication for acute surgical or endovascular treatment for brain infarction was very limited because of the time factor from the onset to admission. It is suggested that neurosurgeons might enlighten citizens about the necessity for acute surgical or endovascular therapy for stroke.

Angioplasty, Balloon, Coronary↗
PubMed2000

Preparations of recombinant HIV-1 p66 antigen to improve the specificity of immune complex transfer enzyme immunoassay of antibody IgG to HIV-1 reverse transcriptase.

Recombinant HIV-1 p66 (rp66, a subunit of reverse transcriptase (RT), a heterodimer of p66 and p51) was produced in Escherichia coli in three different ways. First, rp66 was produced as a part of the fusion protein of lacZ protein and HIV-1 pol protein consisting of three components: protease (p10), RT (p51/p66), and integrase (p31), and was released from the fusion protein by the protease (pol-rp66). Second, rp66 with Ser-Ser at the N-terminus was produced as a fusion protein with maltose-binding protein containing a factor Xa site between the two proteins (MBP-Ser-Ser-rp66) and was released from the fusion protein by factor Xa (Ser-Ser-rp66). Third, rp66 with Met-Gly at the N-terminus was produced in transformed cells (Met-Gly-rp66). The recombinant proteins were purified from sonic extracts of transformed cells by ammonium sulfate fractionation and various column chromatographies. MBP-Ser-Ser-rp66 and Met-Gly-rp66 were readily purified in sufficient amounts for labeling with 2, 4-dinitrophenyl groups and beta-D-galactosidase from E. coli, but pol-rp66 and Ser-Ser-rp66 were not for enzyme-labeling. Ser-Ser-rp66 was not only polymerized but also degraded to considerable extents. The purified preparations were labeled with 2,4-dinitrophenyl groups and beta-D-galactosidase and were tested in immune complex transfer enzyme immunoassay of antibody IgG to HIV-1 RT using serum samples from 600 HIV-1 seronegative and 30 HIV-1 seropositive subjects. Among various combined uses of the two labeled preparations, the uses of 2,4-dinitrophenylated MBP-Ser-Ser-rp66 and pol-rp66 with beta-D-galactosidase-labeled Met-Gly-rp66 showed the highest (99.8%) and the second highest (99.5%) specificities, which were higher than that with the labeled preparations used in the previous study (98. 0%).

Amino Acid Sequence↗
PubMed2000

[Randomized comparative study of CMF (cyclophosphamide, methotrexate and 5-fluorouracil) and UFT-tamoxifen regimens as adjuvant chemotherapy after surgery for breast cancer: Tochigi Prefectural Study Group for Post-Breast Cancer Adjuvant Chemotherapy].

This prospective randomized study aimed at establishing the optimal postoperative adjuvant chemotherapy regimen for premenopausal n+ breast cancer patients. The treatments were Regimen A, comprising 6 courses of CMF (cyclophosphamide, 100 mg/body on days 1-14; methotrexate, 40 mg/m2 on days 1 and 8; and 5-fluorouracil, 500 mg/m2 on days 1 and 8), and Regimen B, consisting of UFT (300 mg/day) and tamoxifen (30 mg/day) administered orally each day for 2 years. Telephone registration allocated the patients to the treatment groups by the minimization method in relation to the T category, number of n+ lesions and estrogen receptor status. Forty-five patients were registered, and 44 of them were eligible (22 cases each to Regimen A and Regimen B). The principal background factors showed no biases between the groups. The adverse reaction incidence was significantly higher with Regimen A (90.9% vs 22.7%). The 5-year survival rate was 89.8% with Regimen A and 100% with Regimen B, while the 5-year disease-free rates were 64.5% and 76.3%, showing no statistical significance. Regimen B showed a better QOL rating after 6 months of therapy in relation to nausea-vomiting and hair loss, and after 24 months in relation to appetite, sleep, performance status, happiness, anorexia and hair loss.

Adult↗
PubMed2000

Expression of thymidylate synthase in relation to survival and chemosensitivity in gastric cancer patients.

Expression of thymidylate synthase (TS) has been studied as a prognostic factor and mechanism of drug resistance in gastric cancers. The relationship between TS expression in surgically resected specimens and clinicopathological factors was examined in 216 gastric cancer patients. Immunohistochemical demonstration of the protein was achieved using an anti-TS polyclonal antibody. Positive TS staining was observed in 50 patients (23.1%). Lymph node metastasis was more frequent in patients with TS-positive tumors than in those with TS-negative tumors (P<0.01). Patients were followed for more than 5 years and survival was examined. In 163 patients who received fluorouracil (FU)-based chemotherapy, the overall 5-year survival rate was 41.8% for patients with TS-positive tumors and 57.0% for patients with TS-negative tumors (P<0.01). In the 53 patients who did not receive chemotherapy, these figures were 25.6% and 79.5%, respectively (P<0.05). In patients with T3 gastric cancer who were treated with curative gastrectomy, however, FU-based chemotherapy did not affect survival of either patients with TS-positive tumors or with TS-negative tumors. Multivariate analysis also revealed TS expression to be a significant variable for predicting postoperative survival (P<0.05). These results indicate that TS expression can be used as an independent prognostic factor for patients with gastric cancer. However, TS expression is not a major predictor of the efficacy of FU-based chemotherapy.

Adult↗
PubMed2000

[Current HIV therapy and its clinical problems].

HIV-specific protease inhibitors(PI) have been available in Japan since 1997. Since then, highly active anti-retroviral therapy(HAART) including two reverse transcriptase inhibitors combined with PI became the main strategy of HIV treatment. After introducing HAART, incidence of most opportunistic infections dramatically decreased, resulted a steep decline of AIDS death in Japan as well as in the United States. However, several unexpected problems related to HAART have been coming up. One is a lipodystrophy syndrome(LDS) which is a novel side effect caused by PI. Lipid disposition was noted associated with hyperlipidemia and/or hyperglycemia. Ischemic heart diseases will emerge in patients with LDS in future. Another one is inflammatory reactions to some opportunistic pathogens, such as Mycobacteria, Pneumocystis carinii, cryptococcus, and so on, occurred during course of immune reconstitution after HAART. This reaction is sometimes too severe to continue HAART and corticosteroid is often required to control the reaction. How to diagnose and how to manage the reaction are to be determined in future.

Drug Therapy, Combination↗
PubMed2000

[Common carotid artery dissection propagated from acute aortic dissection: a case successfully treated by PTA].

We reported a rare case, which was successfully treated by PTA, of right common carotid artery dissection propagated from acute aortic dissection (AAD) type A. A 45-year-old male with a past history of hypertension and an artificial graft replacement of the abdominal aorta due to AAD type B, 7 years ago, was brought into our hospital by ambulance 30 minutes after an attack of fainting and left hemiparesis. On admission, the patient complained not of chest pain or left hemiparesis, but nausea. At that time his consciousness level was JCS 1. During examinations, he had the same attack twice and his consciousness level deteriorated to JCS 2. Brain MRI showed no abnormality, but cervical MRA did not visualize the right carotid artery and thoracic CT depicted acute aortic dissection including branches of the aorta. Emergent angiography disclosed that the dissecting 99% stenosis of the right common carotid artery had developed from AAD type A with poor collateral blood flow. PTA was carried out 8 times and reduced the residual stenosis to about 50% with shortened circulation time. The patient's consciousness disturbance improved. After the replacement of the whole aortic arch in an artificial graft, the residual stenosis disappeared. The patient recovered without neurological deficit but right frontal silent embolic infarction caused by the artificial graft replacement was detected. AAD is a catastrophic illness and sometimes accompanied by devastating ischemic cerebral disease (ICD) because of propagation of dissecting to extracranial vessels. This is the first report that shows the efficacy of PTA for treatment of ICD associated with AAD.

Acute Disease↗
PubMed2000

Mutated p53 in tumors, mutant p53 and p53-specific antibodies in the circulation in patients with gastric cancer.

The accumulation of mutated p53 in tumor cells results in the presence in the circulation of mutant p53 (p53m) and the production of p53-specific antibodies (p53Ab). We examined the relationships among these phenomena and analyzed their clinical implications in 62 patients with gastric cancer at various stages. Expression of p53 in tumors was studied by an immunohistochemical method and circulating p53m and p53Ab were quantitated with commercially available enzyme-linked immunosorbent assay kits. The detectable expression of p53 in tumors and circulating p53Ab was recognized in 28 (45.2%) and 7 (11.3%) of the 62 patients, respectively. The number of patients with higher levels of circulating p53m increased with the progression of the depth of cancer invasion. Patients with any positive findings for the three p53-related parameters had a poorer prognosis, and the difference was statistically significant in patients with p53Ab. When survival was analyzed in terms of the combination of the three p53-related parameters (detectable expression of p53 in tumor cells, high levels of p53m and p53Ab in the circulation), a significantly poorer prognosis was associated with an increase in the number of positive parameters. Analysis of p53 in tumor cells, together with analysis of circulating p53m and p53Ab, could improve the accuracy of prognosis in patients with gastric cancer.

Aged↗
PubMed1999

Anti-HIV effect of saquinavir combined with ritonavir is limited by previous long-term therapy with protease inhibitors.

Combination therapy of saquinavir (SQV) and ritonavir (RTV) seems to have a strong antiretroviral effect pharmacokinetically. The purpose of this study was to examine the effectiveness of combined therapy using SQV and RTV in patients previously treated with protease inhibitors (PIs) and to identify the factors compromising the response to such combination therapy. Nineteen HIV-infected Japanese patients participated in this trial between June 1997 and July 1998, and were monitored until November 1998. Patients were treated with SQV (400 mg twice daily) and RTV (300 or 400 mg twice daily). Among the 17 patients who continued such therapy for longer than 3 months, 6 were responders. Among nonresponders, the duration of PI therapy was longer and a higher frequency of preexisting PI resistance viral mutations was detected than in responders. No significant differences were found in previous use of reverse transcriptase inhibitor therapy, CD4+ and CD8+ T cell counts, viral load at baseline, and plasma concentrations of SQV and RTV between responders and nonresponders. Our results suggest that the response to SQV combined with RTV therapy is complicated by previous long-term treatment with PIs, probably owing to multiple PI resistance mutations. Even in patients with a PI-sensitive HIV genotype, however, resistance mutations can develop during therapy and abrogate the effect of high plasma SQV concentrations.

Adolescent↗
PubMed1999

The expression of transforming growth factor-beta1 is significantly correlated with the expression of vascular endothelial growth factor and poor prognosis of patients with advanced gastric carcinoma.

BACKGROUND: Transforming growth factors beta (TGFs beta) are involved in a variety of important cellular functions, including cell growth and differentiation, adhesion, migration, extracellular matrix formation, and immune function. Moreover, it has been reported that TGFs beta are correlated with angiogenesis. However, the role of TGF-beta as an angiogenic factor in gastric carcinoma is still unclear. METHODS: TGF-beta1 expression was determined in 101 patients with gastric carcinoma by immunohistochemical procedures, and this expression was compared in the current study with both the expression of vascular endothelial growth factor (VEGF), which is thought to be the most potent angiogenic factor, and microvessel density, to evaluate the effect of TGF-beta1 on the angiogenesis of gastric carcinoma tissues. RESULTS: TGF-beta1 expression was detected in 23 tumors (22.8%). TGF-beta1 expression was more frequent in differentiated than in undifferentiated gastric carcinoma. Furthermore, TGF-beta1 expression was significantly correlated with the depth of invasion and the stage of disease. There was a close correlation between TGF-beta1 expression and VEGF expression. There was no correlation between TGF-beta1 expression and microvessel density, whereas VEGF expression was significantly correlated with microvessel density. With regard to prognosis, the 5-year survival rate was 55.9% for patients with TGF-beta1 positive tumors and 67.0% in patients with TGF-beta1 negative tumors. Accordingly, the prognosis for patients with TGF-beta1 negative tumors was significantly better than that for patients with TGF-beta1 positive tumors. Multivariate analysis indicated that lymph node metastasis, tumor size, and TGF-beta1 expression were independent prognostic factors. CONCLUSIONS: These results suggest that TGF-beta1 might be associated with tumor progression by indirectly stimulating angiogenesis through the up-regulation of VEGF expression in gastric carcinoma.

Adenocarcinoma↗