Search PubMed⌕ Search

Biomedical subjects

H Sekihara

Publications and source records attributed to H Sekihara.

At least 73 records · Page 4Linked to original sources
PubMed1998

Human hepatocyte clonal cell lines that support persistent replication of hepatitis C virus.

We previously found that a human T-cell leukemia virus type I infected T-cell line, MT-2, was susceptible to hepatitis C virus (HCV) infection, and that cloned MT-2C cells could support HCV replication more persistently than the parental MT-2 cells. Recently we found that a non-neoplastic hepatocyte line, PH5CH, showed good susceptibility to HCV infection. In this study, we cloned PH5CH cells to obtain cells that supported more persistent HCV replication, and consequently three clones (PH5CH1, PH5CH7 and PH5CH8) in which intracellular HCV RNA could be detected at least 25 days postinoculation (p.i.) were obtained. Semi-quantitative analysis of HCV RNA indicated that HCV replicated in these cloned PH5CH cells was released into the culture medium. Semi-quantitative analysis of internalized HCV RNA after treatment of cloned PH5CH cells and parental PH5CH cells with proteinase K immediately after virus inoculation revealed that PH5CH1, PH5CH7 and PH5CH8 cells contained 10-fold higher levels of HCV RNA than low susceptible cloned PH5CH or parental PH5CH cells. Furthermore, we demonstrated that HCV replication was maintained for 70-100 days in these three clonal lines when the temperature of cell culture after virus inoculation was reduced from 37 to 32 degrees C. Moreover, we demonstrated that interferon alpha had antiviral effect on HCV-infected PH5CH8 cells. The three PH5CH clones obtained in this study will provide a useful tool for the study of HCV replication and proliferation, and for development of an assay system for antiviral agents.

Antiviral Agents↗
PubMed1998

Dehydroepiandrosterone (DHEA) ameliorates the insulin sensitivity in older rats.

To evaluate whether dehydroepiandrosterone (DHEA) ameliorates the decreased insulin sensitivity in older rats, hyperinsulinemic euglycemic clamp studies were performed in rats of various age groups previously treated with DHEA. The glucose metabolic clearance rate (MCR) of the control rats showed a gradual decline with the advancing ages (MCR = 13.05 - 0.027*age (days), r2=0.683, p < 0.01, n = 18). The glucose MCR of the DHEA-treated rats also showed a gradual decline with the aging process (MCR = 12.67 - 0.011*age (days), r2=0.429, p < 0.01, n = 18). However, the MCR of the DHEA-treated rats were significantly higher than that of control rats. As glucose MCR is a parameter which indicates the insulin sensitivity in various tissues, especially in muscles and body composition, was not changed after the injection of DHEA, DHEA is considered to work on muscles to increase insulin sensitivity.

Aging↗
PubMed1998

Reduced serum dehydroepiandrosterone levels in diabetic patients with hyperinsulinaemia.

OBJECTIVE: To elucidate the interaction between insulin and dehydroepi-androsterone (DHEA) concentrations, we evaluated serum DHEA and DHEA-sulphate (DHEA-S) levels in diabetic patients with hyperinsulinaemia. PATIENTS AND DESIGN: Twenty-four subjects with non-insulin dependent diabetes mellitus, 12 hyperinsulinaemic subjects (fasting serum insulin concentrations > or = 10 mU/ml (71.8 pmol/l)) and 12 non-hyperinsulinaemic subjects, and 10 normal control subjects were studied. Serum DHEA, DHEA-S, cortisol and ACTH levels were investigated in these subjects. Moreover, their serum DHEA levels were compared during hyperinsulinaemic-euglycaemic clamp and after ACTH stimulation. MEASUREMENTS: Serum insulin, cortisol, ACTH, DHEA and DHEA-S concentrations were evaluated by RIA. Serum glucose was determined by the glucose oxidase method. RESULTS: Diabetic patients with hyperinsulinaemia showed significantly lower levels of serum DHEA and DHEA-S than controls. After ACTH stimulation, these patients also showed significantly lower DHEA levels. During the hyperinsulinaemic-euglycaemic clamp, serum DHEA concentrations of diabetic patients with hyperinsulinaemia remained low and did not decline further, although those of control subjects and non-hyperinsulinaemic diabetic patients showed a significant decline of serum DHEA levels. Even after ACTH stimulation during the clamp, serum DHEA in hyperinsulinaemic patients was still significantly lower than in controls. CONCLUSIONS: In diabetic patients with hyperinsulinaemia, baseline DHEA levels are chronically and maximally suppressed compared to control subjects and non-hyperinsulinaemic diabetic patients, and thus not decreased further by exogenous insulin infusion during hyperinsulinaemic-euglycaemic clamp.

Adrenocorticotropic Hormone↗
PubMed1998

Expression of interferon receptor genes (IFNAR1 and IFNAR2 mRNA) in the liver may predict outcome after interferon therapy in patients with chronic genotype 2a or 2b hepatitis C virus infection.

Hepatitis C virus (HCV) genotype 2a or 2b is associated with a favorable outcome after interferon therapy. However, 19% to 33% of patients do not respond to therapy. We investigated whether interferon receptor gene (IFNAR1 and IFNAR2 mRNA) expression in the liver before interferon therapy predicts long-term response to therapy in patients with genotype 2a or 2b HCV infection. Twenty-seven patients who subsequently received interferon-alpha therapy underwent liver biopsies before interferon therapy. Hepatic IFNAR1 and IFNAR2 mRNA were determined using a reverse transcription-polymerase chain reaction assay. Twenty (74%) patients responded to interferon therapy, while the remaining seven (26%) patients were nonresponders. The expression rates of IFNAR1 and IFNAR2 mRNA in the liver were significantly higher in responders than nonresponders (p < 0.01, by chi-square test). The presence of either IFNAR1 or IFNAR2 mRNA predicted complete response to interferon treatment, with a positive predictive value of 100%. Multiple logistic regression analysis showed that IFNAR1 and/or IFNAR2 mRNA expression was the only significant predictor of the effectiveness of IFN therapy (p = 0.0002). We conclude that expression of interferon receptor genes in the liver is a useful index for predicting the long-term efficacy of interferon therapy in patients with chronic genotype 2a or 2b HCV infection.

Adult↗
PubMed1998

Pancreatic exocrine dysfunction associated with mitochondrial tRNA(Leu)(UUR) mutation.

We report on pancreatic exocrine dysfunction in families that have the mitochondrial tRNA(Leu)(UUR) gene mutation. These families exhibited maternally inherited diabetes mellitus (DM) and an A to G substitution at nt 3243 of the mitochondrial tRNA(Leu)(UUR) gene (A3243G mutation). Pancreatic necropsy samples from one proband showed accumulation of degenerated mitochondria in pancreatic acinar cells. Pancreatic exocrine dysfunction was recognised by a functional pancreatic study. This study indicates that exocrine pancreatic dysfunction may be associated with the A3243G mutation.

4-Aminobenzoic Acid↗
PubMed1998

Dehydroepiandrosterone decreases serum tumor necrosis factor-alpha and restores insulin sensitivity: independent effect from secondary weight reduction in genetically obese Zucker fatty rats.

Dehydroepiandrosterone (DHEA) and its sulfate ester are the most abundant circulating adrenal steroids in humans. Administration of DHEA has been reported to have beneficial effects on obesity, hyperlipidemia, diabetes, and atherosclerosis in obese rodents, although its effects on insulin resistance have not been fully elucidated. In this study, the effects of DHEA treatment on insulin sensitivity were investigated in genetically obese Zucker rats, an animal model of insulin resistance, using the euglycemic clamp technique. After 0.4% DHEA was administered for 10 days to female obese Zucker rats aged 16 weeks, body weight and plasma insulin decreased and glucose disposal rate (GDR), which was normally reduced in obese rats, rose significantly compared with age- and sex-matched control obese rats. On the other hand, although the pair-fed obese rats also showed levels of weight reduction similar to those of DHEA-treated rats, the increase in GDR of DHEA-treated rats was significantly greater than in pair-fed rats, suggesting a direct ameliorating effect of DHEA on insulin sensitivity of obese rats. Serum concentration of tumor necrosis factor (TNF)-alpha, one of cytokines causing insulin resistance, was also reduced significantly in DHEA-treated, but not in pair-fed obese rats. In conclusion, our results suggest that DHEA treatment reduces body weight and serum TNF-alpha independently, and that both may ameliorate insulin resistance in obese Zucker fatty rats.

Animals↗
PubMed1998

Ocular arterial flow hemodynamics in patients with diabetes mellitus.

The purpose of this study was to investigate ocular blood flow hemodynamics in patients with diabetes mellitus. We used color Doppler sonography, in 22 normal subjects and 52 patients with (n = 25) or without (n = 27) diabetic retinopathy, to determine blood flow velocities and the resistive index of the central retinal artery. The resistive index of the central retinal artery in patients with diabetic retinopathy (0.85 +/- 0.09) was significantly greater (P < 0.01) than that in normal subjects (0.72 +/- 0.08) and in patients without diabetic retinopathy (0.81 +/- 0.09). The resistive index of the central retinal artery in the patients without diabetic retinopathy was also significantly greater than that of normal subjects (P < 0.01). The resistive index of ocular arterial flow was increased in the patients with diabetes mellitus and further increased in the presence of retinopathy. Increased resistance in the peripheral ocular vascular bed contributes to diabetic retinopathy, and this change is present before the appearance of overt diabetic retinopathy.

Blood Flow Velocity↗
PubMed1998

[SMANCS-TAE combined with PEI in the treatment for hepatocellular carcinoma].

From January 1996 to August 1997, 24 patients with advanced hepatocellular carcinoma (HCC) equal to or more than 2 cm (mean +/- SD; 4.1 +/- 3.0 cm) in main tumor diameter were treated by SMANCS-TAE (20 cases) or SMANCS-TAI (4 cases) combined with PEI. Six cases had solitary lesion, 16 cases had multiple lesions, and 2 cases had massive lesions. After this combination therapy, 21 of 24 cases had complete tumor necrosis. During 3 to 19 months follow up period, 12 cases had cancer-free survival (SMANCS-TAI; 3 cases), and 9 cases had tumor recurrences (3 cases were local recurrences and 6 cases involved new lesions). Two cases died of hepatic infarction and cancer death, however, the remaining 22 cases were surviving. SMANCS-TAE combined with PEI is useful treatment for advanced large or multiple HCC lesions in patients who are poor surgical risks.

Aged↗
PubMed1997

Role of insulin receptor substrate-1 and pp60 in the regulation of insulin-induced glucose transport and GLUT4 translocation in primary adipocytes.

In muscle and fat, glucose transport occurs through the translocation of GLUT4 from an intracellular pool to the cell surface. Phosphatidylinositol (PI) 3-kinase has been shown to be required in this process. Insulin is thought to activate this enzyme by stimulating its association with tyrosine-phosphorylated proteins such as insulin receptor substrate (IRS)-1, IRS-2, Grb2-associated binder-1, and pp60. To study the role of these endogenous substrates in glucose transport, we analyzed adipocytes from IRS-1 null mice that we previously generated (Tamemoto, H., Kadowaki, T., Tobe, K., Yagi, T., Sakura, H., Hayakawa, T., Terauchi, Y., Ueki, K., Kaburagi, Y., Satoh, S., Sekihara, H., Yoshioka, S., Horikoshi, H., Furuta, Y. , Ikawa, Y., Kasuga, M., Yazaki Y., and Aizawa S. (1994) Nature 372, 182-186). In adipocytes from these mice, we showed that: 1) insulin-induced PI 3-kinase activity in the antiphosphotyrosine immunoprecipitates was 54% of wild-type; 2) pp60 was the major tyrosine-phosphorylated protein that associated with PI 3-kinase, whereas tyrosine phosphorylaion of IRS-2 as well as its association with this enzyme was almost undetectable; and 3) glucose transport and GLUT4 translocation at maximal insulin stimulation were decreased to 52 and 68% of those from wild-type. These data suggest that both IRS-1 and pp60 play a major role in insulin-induced glucose transport in adipocytes, and that pp60 is predominantly involved in regulating this process in the absence of IRS-1.

Adipocytes↗
PubMed1997

Plus- and minus-stranded hepatitis G virus RNA in liver tissue and in peripheral blood mononuclear cells.

Hepatitis G virus (HGV), which was recently identified, is a single, plus-stranded RNA virus that is thought to replicate via minus-stranded RNA, but no information is available about the distribution of either plus- (genomic) or minus- (replicative) stranded HGV RNAs in HGV infected patients. We, therefore, tested the serum, liver tissue, and peripheral blood mononuclear cells (PBMCs) of six hepatitis patients with HGV infection for the presence of plus- and minus-stranded HGV RNA. The RT-nested PCR was used with primers derived from 5'-noncoding region of the genome. Before RT-PCR analysis, the 3'-termini of RNA specimens were chemically modified to discriminate between plus- and minus-stranded HGV RNA. Plus-stranded HGV RNA was detected in the serum and liver tissue of all six patients and in the PBMCs of five patients. Minus-stranded RNA was detected in the liver tissue of all six patients, in the serum of two patients, and in the PBMCs of one patient. In summary, the detection of minus-stranded HGV RNA in liver tissue may indicate that HGV replicates in the liver.

Flaviviridae↗
PubMed1997

Defective adenoassociated viral-mediated transfection of insulin gene by direct injection into liver parenchyma decreases blood glucose of diabetic mice.

The present study assessed the feasibility of transferring the insulin gene into liver cells of diabetic individuals using a defective adenoassociated viral (AAV) vehicle. AAV offers several advantages over other viral vectors, since this vehicle can facilitate transfection in vivo without cell division and without any viral coding sequences (thus minimizing inflammation). The rat insulin gene and lacZ were each packed into a defective AAV vehicle (AAV-INS and AAV-lacZ, respectively). Successful AAV-mediated transfection and expression of lacZ into hepatocytes in primary cell culture were demonstrated by chemiluminescent assay of beta-galactosidase. Similarly, AAV-mediated transfection and expression of the insulin gene into hepatocytes was demonstrated by immunocytochemistry and reverse-transcriptase polymerase chain reaction (RT-PCR). After AAV-mediated transfection of the insulin gene into hepatocytes, glucose in the medium was significantly reduced for up to 5 days. After direct injection of AAV-INS into liver parenchyma of diabetic mice, successful transfection was demonstrated by RT-PCR, and blood glucose was significantly decreased for at least 6 days. These studies suggest that the AAV vector may be used to transfer the insulin gene into liver cells in vitro and in vivo.

Animals↗
PubMed1997

Modulation of tissue angiotensinogen gene expression in genetically obese hypertensive rats.

Wistar fatty rats (WFR) show obesity and obesity-related features, including hypertension. In this study, we examined the expression of angiotensinogen mRNA in a variety of tissues at different times in WFR and control Wistar lean rats (WLR). WFR were obese and hypertensive at 16 and 24 wk. Plasma renin activity and plasma angiotensinogen concentration showed age-dependent increases in WFR but decreases in WLR. Northern blot analysis showed no significant differences in the levels of hepatic and renal angiotensinogen mRNA between WFR and WLR, and the levels of fat and adrenal angiotensinogen mRNA were lower in WFR than in WLR. On the other hand, the levels of cardiac angiotensinogen mRNA at 16 and 24 wk and those of aortic angiotensinogen mRNA at 16 wk were significantly higher in WFR than in WLR. These results show that the expression of tissue angiotensinogen mRNA is regulated differently in WFR and WLR and indicate that the development of hypertension in WFR is accompanied at least temporally with increases in plasma angiotensinogen concentration as well as in cardiac and aortic angiotensinogen mRNA. Moreover, these results suggest the existence of obesity hypertension-linked and tissue-specific regulation of angiotensinogen gene expression.

Angiotensinogen↗
PubMed1997

Reversibly increased lymphocyte response to mitogens in a young man with isolated adrenocorticotropic hormone deficiency.

A 21-year-old man with isolated adrenocorticotropic hormone (ACTH) deficiency complained of loss of consciousness in association with hypoglycemia. Both plasma ACTH and cortisol levels were low and failed to respond to corticotropin-releasing hormone (CRH) stimulation. The patient also showed abnormal findings in hematological examination, such as neutropenia and anemia with lymphocytosis, activity of coagulation factors, and electroencephalography (EEG). Furthermore, mitogen-induced lymphocyte proliferation was increased. After successful replacement therapy with hydrocortisone 15 mg/day, most of these abnormalities including the lymphocyte proliferation were fully restored.

Adrenocorticotropic Hormone↗
PubMed1997

Use of hepatic tumor index on color Doppler sonography for differentiating large hepatic tumors.

OBJECTIVE: Color flow patterns on Doppler sonography are nonspecific for differentiating various hepatic tumors. We previously reported that a tumoral peak systolic flow velocity of 0.40 m/sec or greater suggested a malignant hepatic tumor rather than a hemangioma. However, tumoral peak systolic flow velocity failed to differentiate hepatocellular carcinomas and metastatic tumors. In this study, we attempted to assess the value of the hepatic tumor index for differentiating hepatocellular carcinomas and other hepatic tumors. MATERIALS AND METHODS: Color Doppler sonography was performed in 80 patients with 108 hepatic lesions larger than 2.0 cm in diameter. The hepatic tumor index was calculated as the ratio of the tumoral peak systolic velocity to the peak systolic velocity of the right or left hepatic artery. RESULTS: Pulsatile color flow images were obtained in 42 of 48 hepatocellular carcinomas, 25 of 32 hepatic metastases, and 13 of 28 hemangiomas. The mean hepatic tumor indexes obtained from hepatocellular carcinomas, metastases, and hemangiomas were 1.14 +/- 0.37 (+/-SD), 0.63 +/- 0.22, and 0.60 +/- 0.17, respectively. The hepatic tumor indexes of hepatocellular carcinomas significantly exceeded those of metastases and hemangiomas (p < .01 in both cases). A hepatic tumor index equal to or greater than 1.0 was associated with 76% sensitivity, 92% specificity, and 82% accuracy in distinguishing hepatocellular carcinomas from hepatic metastases. In lesions with a tumoral peak systolic velocity of 0.40 m/sec or greater, a hepatic tumor index equal to or greater than 1.0 was associated with 91% sensitivity, 83% specificity, and 89% accuracy in distinguishing hepatocellular carcinomas from hepatic metastases. CONCLUSION: The hepatic tumor index on color Doppler sonography was useful in differentiating large hepatocellular carcinomas from hepatic metastases.

Adult↗
PubMed1997

[A case of mitochondrial cardiomyopathy with heart failure, sick sinus syndrome and diabetes mellitus: mitochondrial DNA adenine-to-guanine transition at 3243 of mitochondrial tRNA(LEU)(UUR) gene].

A 42-year-old woman with diabetes mellitus lost consciousness and was transferred to the Yokohama City University Hospital. Blood chemistry findings indicated low blood sugar levels and chest X-ray examination revealed cardiomegaly and bilateral pleural effusions. These clinical abnormalities were corrected by treatment with glucose, diuretics, angiotensin converting enzyme inhibitor and digitalis. Cardiological laboratory examinations were performed after admission. Electrocardiography revealed first degree atrioventricular block and incomplete right bundle branch block. Ultrasonography showed lower grade of ejection fraction and diffuse hypokinesis of the cardiac wall. After admission, sinus arrest suddenly occurred. The diagnosis was sick sinus syndrome. Scintigraphy using iodine-123 betamethyl-p-iodophenyl-pentadecanoic acid showed abnormal mottled defects. Coronary angiography found no significant stenosis of the coronary artery. Electron microscopy showed abnormally shaped mitochondrial accumulations in an endomyocardial biopsy specimen. Mitochondrial DNA amplification by polymerase chain reaction followed by restriction enzyme Apa I digestion revealed adenine-to-guanine transition at 3243 of the mitochondrial tRNA(LEU)(UUR) gene.

Adult↗
PubMed1997

Changes in DNA copy number in primary gastric carcinomas by comparative genomic hybridization.

We examined 33 primary gastric carcinomas using comparative genomic hybridization to detect changes in the DNA copy number and the chromosomal location of these changes. Ninety-four percent (31 of 33) showed 1 or more DNA copy number changes, such as increases at 2p23-p25 (observed in 21% of the total cases), 3q26.3-q27 (24%), 7p15 (24%), 9p22-pter (18%), and 13q22-q34 (21%) and decreases at 1p34.2-p36.2 (18%) and Y (52%). Histological examination indicated that increases at 3q26.1-q26.3 and 7p15 and decreases at 1p36.1-p36. 2 and Y were commonly observed in both differentiated and undifferentiated types. Increases at 3q27, 6q23-q25, and 7cen-p14 and decreases at 1p34.2-p35 and 17p12 were predominantly observed in the differentiated type, and increases at 2p23-pter, 9p22-pter, and 13q31-qter and a decrease at 6p21.3 were predominantly observed in the undifferentiated type. In addition, clinical staging of tumors showed that increases at 2p23-p25, 7p14-p21, 7q31-q32, and 9p22-pter and a decrease at Y were observed in early-stage tumors, whereas increases at 9q32-q33 and 15q26 were observed only in late-stage tumors. Many of the abnormalities detected in this study were not previously reported in gastric carcinomas. Our comparative genomic hybridization results indicate the presence of genetic alterations that may play some important role in the development and progression of gastric carcinomas.

Adult↗