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Biomedical subjects

T Ohtani

Publications and source records attributed to T Ohtani.

At least 55 records · Page 3Linked to original sources
PubMed1999

A new parameter in decision making for transurethral electroresection of benign prostate hyperplasia.

OBJECTIVE: In this study, the clinical usefulness of transition zone (TZ) volume (TZV) measured by transrectal ultrasonography (TRUS) was investigated as a new parameter for the preoperative prediction of the treatment efficacy of transurethral resection of the prostate (TURP). METHODS: Fifty-six men with symptomatic benign prostatic hyperplasia (BPH; age 68.6 +/- 9.7 years) underwent TURP and were evaluated based on ordinary BPH parameters such as the international prostatic symptom score (I-PSS), quality of life (QOL) score, peak urine flow and entire prostate volume (PV), as well as the new TZV parameters and calculation of the TZ index. Relative risks were adjusted simultaneously for potentially confounding variables by multiple logistic regression analysis after adjustment for age, QOL, I-PSS, Qmax and residual urine. RESULTS: The adjusted relative risk for TURP at a TZ index of 0.1 increased to 4.5 (95% confidence interval 2.3-8.78). In general, poor responses were observed in patients with less symptomatic scores or lower values prior to operation, but there was a weak correlation between treatment outcome and preoperative scores or values of ordinary parameters. The volume parameters of BPH and PV did not predict treatment efficacy preoperatively, but TZV and the TZ index correlated with the treatment efficacy of TURP. CONCLUSION: TZV and the TZ index seem to be useful new parameters in preoperative decision-making with regard to TURP.

Aged↗
PubMed1999

Signaling through Gp130: toward a general scenario of cytokine action.

Cytokines play roles in a wide range of responses such as immune response, hematopoiesis and inflammation. A large volume of studies revealed that cytokines show functional pleiotropy and redundancy. Gp130 is a receptor subunit shared by the interleukin-6 family of cytokines. We describe and discuss signaling through gp130 in relation to a general scenario for cytokine signaling regulating cell growth, differentiation and survival.

Animals↗
PubMed1998

STAT3 orchestrates contradictory signals in cytokine-induced G1 to S cell-cycle transition.

The signal transducer and activator of transcription molecules (STATs) play key roles in cytokine-induced signal transduction. However, their role in cell growth has not been clear. In the present study, we show that STAT3 plays a key role in the G1 to S phase cell-cycle transition induced by the cytokine receptor subunit gp130, through the upregulation of cyclins D2, D3 and A, and cdc25A, and the concomitant downregulation of p21 and p27. Furthermore, unexpectedly, we found that gp130 could induce the expression of p21 when STAT3 activation was suppressed. Such contradictory signals regulating cell-cycle progression could be simultaneously delivered from distinct cytoplasmic regions of gp130. We propose an 'orchestrating model' for cytokine and growth factor action in which contradictory signals are orchestrated to produce a specific effect in a target cell.

Cell Line↗
PubMed1998

Changes of immunological markers after autologous peripheral blood stem cell transplantation.

PURPOSE: Recently high-dose chemotherapy with peripheral blood stem cell transplantation (PBSCT) has become an important treatment for hematological and solid tumors. METHODS: Immunological parameters were examined before and after PBSCT in 9 patients with lung cancer and 13 patients with malignant lymphoma. Findings were compared with those for bone marrow transplantation (BMT). Peripheral blood cells were analyzed for phenotype and the levels of cytokines and soluble factors were measured. RESULTS: After PBSCT, activated T cells (CD3+HLA-DR+ cells, CD8+HLA-DR+ cells) and suppressor/cytotoxic T cells (CD8+CD11b- cells) were significantly higher in the patients with lung cancer than in those with malignant lymphoma. Serum levels of interleukin-4 and soluble interleukin-2 receptor were also significantly higher in the patients with lung cancer than in those with lymphoma. On the other hand, the serum levels of interferon gamma, tumor necrosis factor alpha, interleukin-6, soluble human leukocyte antigen class 1, and soluble thrombomodulin were significantly increased after bone marrow transplantation. The transfused peripheral stem cells of lung cancer and lymphoma patients had a similar number of granulocyte/macrophage-colony-forming units, but lung cancer patients had significantly more CD34-positive cells. CONCLUSION: By reinfusing large numbers of autologous immune cells, PBSCT may accelerate immune reconstitution, with T cells being likely to have a marked therapeutic potential. The changes after PBSCT were greater in patients with lung cancer than in lymphoma patients. These blood cells are potent mediators of anticancer activity and could play an important role in the elimination of autologous malignant cells.

Adult↗
PubMed1998

Gab1 acts as an adapter molecule linking the cytokine receptor gp130 to ERK mitogen-activated protein kinase.

Gab1 has structural similarities with Drosophila DOS (daughter of sevenless), which is a substrate of the protein tyrosine phosphatase Corkscrew. Both Gab1 and DOS have a pleckstrin homology domain and tyrosine residues, potential binding sites for various SH2 domain-containing adapter molecules when they are phosphorylated. We found that Gab1 was tyrosine phosphorylated in response to various cytokines, such as interleukin-6 (IL-6), IL-3, alpha interferon (IFN-alpha), and IFN-gamma. Upon the stimulation of IL-6 or IL-3, Gab1 was found to form a complex with phosphatidylinositol (PI)-3 kinase and SHP-2, a homolog of Corkscrew. Mutational analysis of gp130, the common subunit of IL-6 family cytokine receptors, revealed that neither tyrosine residues of gp130 nor its carboxy terminus was required for tyrosine phosphorylation of Gab1. Expression of Gab1 enhanced gp130-dependent mitogen-activated protein (MAP) kinase ERK2 activation. A mutation of tyrosine 759, the SHP-2 binding site of gp130, abrogated the interactions of Gab1 with SHP-2 and PI-3 kinase as well as ERK2 activation. Furthermore, ERK2 activation was inhibited by a dominant negative p85 PI-3 kinase, wortmannin, or a dominant negative Ras. These observations suggest that Gab1 acts as an adapter molecule in transmitting signals to ERK MAP kinase for the cytokine receptor gp130 and that SHP-2, PI-3 kinase, and Ras are involved in Gab1-mediated ERK activation.

Adaptor Proteins, Signal Transducing↗
PubMed1998

High Fas ligand expression on lymphocytes in lesions of ulcerative colitis.

BACKGROUND: The pathogenesis of ulcerative colitis is unclear, but cytotoxic T lymphocytes infiltrating the mucosa have been implicated in mucosal damage. The Fas ligand (FasL), expressed on cytotoxic T lymphocytes, induces apoptosis in cells expressing Fas. AIM: To analyse FasL expression in affected colonic mucosa to ascertain Fas-FasL interaction in ulcerative colitis. METHODS: FasL mRNA was quantified in colonic mucosal specimens from healthy subjects and patients with ulcerative colitis or Crohn's disease, using the competitive reverse transcription polymerase chain reaction. FasL mRNA localisation was determined by in situ hybridisation. Expression of Fas in colonic mucosa was analysed immunohistochemically. Phenotypes of lamina propria lymphocytes that expressed FasL were analysed by flow cytometry. RESULTS: FasL mRNA was strongly expressed in active ulcerative colitis lesions, but not in those associated with active Crohn's disease or active proctitis-type ulcerative colitis. In situ hybridisation showed that FasL mRNA expression occurred in mononuclear cells infiltrating lesions. Fas was expressed in epithelial cells in ulcerative colitis and Crohn's disease, and in normal subjects. Cytometry showed that FasL was expressed in CD3 lymphocytes infiltrating the lamina propria in active lesions. CONCLUSIONS: FasL is expressed in CD3 lymphocytes infiltrating into ulcerative colitis but not Crohn's disease lesions, suggesting that Fas-FasL induced apoptosis participates in the mucosal damage of ulcerative colitis.

Acute Disease↗
PubMed1998

Vitamin E reduces glucocorticoid-induced growth inhibition and lipid peroxidation in rats.

This experiment was conducted to study the effects of vitamin E on growth inhibition and lipid peroxidation in rats treated with different levels of corticosterone (CTC). Rats (Sprague-Dawley strain, 5 weeks of age) were divided into two groups: control group receiving a basal diet containing 60 mg DL-alpha-tocopheryl acetate/kg diet, and vitamin E group receiving the same diet supplemented with 5,000 mg tocopherol. After 6 days, rats of both diet groups were further divided into three groups by dose levels of CTC treatment (0, 25, and 100 mg CTC/kg body weight/d). CTC was administered to the rats by subcutaneous injection for 4 d. Growth was dose-dependently inhibited by the CTC treatment. Feeding the vitamin E diet significantly (p < 0.05) improved growth retardation. Feed efficiency was lowered by CTC treatment, while this was significantly (p < 0.05) minimized by feeding the vitamin E diet. Lipid peroxidation (TBARS) in the liver was elevated by the CTC treatment (p < 0.001) when the rats were fed the basal diet. The increment in TBARS was significantly (p < 0.001) reduced by vitamin E. The activities of glutathione S-transferase (GST) and superoxide dismutase (SOD) were significantly reduced by the CTC treatment in a dose-dependent manner in both dietary groups. Feeding vitamin E significantly (p < 0.001) improved the reduction in GST activity. The SOD activity showed some tendency. The present results demonstrate the effectiveness of vitamin E in improving growth retardation in glucocorticoid-treated rats and suggest that reductions in increased lipid peroxidation due to CTC may be an important factor of the action of vitamin E.

Animals↗
PubMed1998

Vitamin E reduces glucocorticoid-induced oxidative stress in rat skeletal muscle.

The purpose of this study was to investigate the effect of vitamin E on oxidative stress in the skeletal muscle of glucocorticoid-treated rats. Male Sprague-Dawley rats (5 weeks of age) were fed a basal diet or a diet supplemented with vitamin E (5,000 mg DL-alpha-tocopheryl acetate/kg diet) for 10 d. The rats of both diet groups received subcutaneous injections of corticosterone (CTC) (0, 25, and 100 mg/kg body weight/d) during the final 4 d. Weights of the extensor digitorum longus and gastrocnemius (GAST) muscles were dose-dependently reduced by CTC. However, the muscle weight losses in rats fed the vitamin E diet were smaller than those in rats fed the basal diet. Protein carbonyl content in the GAST muscle, which was determined as an index of oxidatively modified protein, was increased by 100 mg of CTC, and the increment was significantly (p < 0.01) reduced by vitamin E supplement. Hyperglycemia was induced by 100 mg of CTC, but it was not affected by vitamin E. Lipid peroxide (TBARS) in plasma and in GAST muscle was elevated by 100 mg of CTC, and vitamin E significantly (p < 0.001) suppressed the formation of TBARS in the muscle. The change in TBARS paralleled that in protein carbonyl. These results show that CTC leads to oxidative stress in rat skeletal muscles and that vitamin E has roles in reducing the oxidative stress which causes muscle atrophy.

Animals↗
PubMed1998

[Mechanical properties of titanium casting obtained using short-time cast procedure].

The purpose of this study was to investigate the mechanical properties of titanium casting obtained using short-time cast procedure. A commercial phosphate-bonded investment for titanium casting were used. And dumbbell-shaped specimens with phi 2 mm x 14 mm parallel portion were cast according to manufacture instruction and by way of three different short-time cast procedures. Then, micro vickers hardness test and tensile test were performed with these specimens. In the hardness test, the micro vickers hardness of 50 approximately 250 microns deep location from specimen surface was ranged from 192.8 to 259.0 Hv; there were significant difference among both the location factor and the casting procedure factor by the two-way ANOVA (p < 0.05). In the tensile test, tensile strength, yield strength, elastic modulus and elongation were obtained: these tensile properties of short-time cast procedures were not significantly different from those of manufacture instruction. These results indicated that the short-time cast procedure for titanium casting was available in the point of mechanical properties. It was, however, not obvious that how the short-time cast procedures effected the dimensional accuracy of titanium casting. Therefore, further investigation was needed for the practical usage of this method.

Dental Casting Technique↗
PubMed1998

Early intraperitoneal dissemination after radical resection of unsuspected gallbladder carcinoma following laparoscopic cholecystectomy.

We describe a case of early intraperitoneal dissemination after a radical second operation following laparoscopic cholecystectomy for unsuspected locally advanced carcinoma of the gallbladder. A radical procedure including wedge resection of the gallbladder bed, resection of the extrahepatic bile ducts, and dissection of the regional nodes and interaortocaval nodes was performed 17 days after laparoscopic cholecystectomy in a 60-year-old woman. The final histologic examination revealed a moderately differentiated adenocarcinoma invading perimuscular connective tissue with one positive pericholedochal node (pT2, pN1, pM0). Despite the absence of intraperitoneal dissemination at reexploration, the patient had intraperitoneal dissemination 5 months after the second operation. Insidious intraperitoneal dissemination may decrease the survival rate of locally advanced carcinoma of the gallbladder after laparoscopic cholecystectomy compared with open cholecystectomy. Surgeons should search for unsuspected carcinoma of the gallbladder intraoperatively to avoid implantation metastasis.

Adenocarcinoma↗
PubMed1997

Combined pancreaticoduodenectomy and hepatectomy for patients with locally advanced gallbladder carcinoma: long term results.

BACKGROUND: The objective of this study was to evaluate the efficacy of combined pancreaticoduodenectomy and hepatectomy for the treatment of patients with locally advanced gallbladder carcinoma. METHODS: Long term results over 5 years of follow-up were analyzed retrospectively in 17 consecutive patients with gallbladder carcinoma who underwent combined pancreaticoduodenectomy and hepatectomy with radical lymphadenectomy. The indications for pancreaticoduodenectomy were direct invasion of the adjacent organs (stomach, duodenum, or pancreas) and/or the presence of peripancreatic (head only) lymph node metastases. The hepatectomy performed was a nonanatomic resection of the gallbladder bed in 15 patients and an extended right hepatectomy in 2 patients. There was 1 in-hospital death (6%). RESULTS: Overall, 5 patients (29%) survived 5 years after surgery. Of these patients, four had Stage IVB disease with positive peripancreatic lymph nodes. Eight of the 10 patients who underwent a potentially curative resection survived longer than 3 years, whereas none of the 7 patients with residual tumor survived beyond 15 months. The 5-year survival of 50% (median survival: 58.5 months) in those undergoing a potentially curative resection was significantly better than the 5-year survival of 0% (median survival: 8 months) observed in those patients with residual tumor (P = 0.00086). CONCLUSIONS: Combined pancreaticoduodenectomy and hepatectomy is an efficacious treatment for patients with locally advanced gallbladder carcinoma, but only if a potentially curative resection is feasible. The presence of peripancreatic (head only) lymph node disease is not a contraindication for this procedure.

Adenocarcinoma↗
PubMed1997

Bromodeoxyuridine-induced expression of endothelin A in A375 human melanoma cells.

Expression of endothelin (ET) receptor subtypes was examined in an experimental model of A375 human melanoma cell differentiation using the pyrimidine analog bromodeoxyuridine (BUdR). BUdR (10 microM)-treated cells had an increased surface area and an increased dendricity, were contact-inhibited and lacked tumorigenecity in athymic nude mice. The untreated A375 cells exclusively expressed ETB and BUdR-induced phenotypical changes were accompanied by induction of ETA expression as evidenced by northern blotting, [125I]ET-1 binding assay and [Ca2+]i measurement. Thus, BUdR-induced differentiation of A375 melanoma cells may provide a model system to study the receptor subtype switch in melanocyte development.

Animals↗
PubMed1997

Patterns of lymphatic spread of carcinoma of the ampulla of Vater.

BACKGROUND: The pattern of lymphatic spread of ampullary cancer is poorly documented. This pattern was clarified in order to define the rational extent of radical lymphadenectomy. METHOD: Thirty-nine consecutive patients who underwent pancreaticoduodenectomy with radical lymphadenectomy were included in the study. A total of 1447 lymph nodes dissected from the resected specimens was examined to detect the presence of metastatic foci. RESULTS: Twenty-one of the 39 patients had a total of 97 positive nodes. The sites of nodal involvement were the posterior pancreaticoduodenal (20 of 21 patients), inferior pancreaticoduodenal artery (IPDA; 12 of 21), anterior pancreaticoduodenal (three of 21), trunk of the superior mesenteric artery (three of 20), pericholedochal (three of 21), retroportal (two of 21), and para-aortic (three of five) regions. No metastases were found in the hepatic artery, cystic duct, perigastric, right coeliac, middle colic artery or right caval node groups. CONCLUSION: Ampullary cancer mainly spreads to the posterior pancreaticoduodenal node group, then to the IPDA node group, and finally to the para-aortic area. The rational extent of radical lymphadenectomy should include the pancreaticoduodenal, superior mesenteric, pericholedochal, retroportal and para-aortic nodes.

Ampulla of Vater↗
PubMed1997

Carcinoma of the uterine cervix with myocardial metastasis.

Cardiac metastasis from pelvic malignancies is rare. We experienced a case of carcinoma of the uterine cervix with myocardial involvement in the right ventricle, and treated this patient with conventional methods until her death. The metastatic tumor was incidentally found in the right ventricle, eroding the myocardium. We used CT, MRI, and gallium scintigraphy to assess the lesion. This aggressive lesion proved fatal for our relatively young patient. We report this case for future reference.

Adult↗
PubMed1997

Lymph node recurrence of gallbladder carcinoma successfully managed by systemic chemotherapy with 5-fluorouracil and mitomycin C: report of a 5-year survivor.

Although gallbladder cancer (GBC) is believed to be chemoresistant, the effectiveness of chemotherapy against lymph node metastasis has been reported. We report a 70-year-old woman with advanced GBC in whom isolated, widespread lymph nodal recurrence after a radical resection responded completely to systemic chemotherapy with mitomycin C and 5-fluorouracil. This patient remains symptom-free with no evidence of disease at 6 years after surgery (5 years after the initiation of chemotherapy). Both our case and a literature review suggest that nodal disease appears more chemosensitive than the primary lesion in GBC. Chemotherapy may provide long-term palliation for selected patients with isolated nodal recurrence.

Aged↗