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T Kuroki

Publications and source records attributed to T Kuroki.

At least 127 records · Page 7Linked to original sources
PubMed1999

Protein kinase Cdelta mediates insulin-induced glucose transport in primary cultures of rat skeletal muscle.

Insulin activates certain protein kinase C (PKC) isoforms that are involved in insulin-induced glucose transport. In this study, we investigated the possibility that activation of PKCdelta by insulin participates in the mediation of insulin effects on glucose transport in skeletal muscle. Studies were performed on primary cultures of rat skeletal myotubes. The role of PKCdelta in insulin-induced glucose uptake was evaluated both by selective pharmacological blockade and by over-expression of wild-type and point-mutated inactive PKCdelta isoforms in skeletal myotubes. We found that insulin induces tyrosine phosphorylation and translocation of PKCdelta to the plasma membrane and increases the activity of this isoform. Insulin-induced effects on translocation and phosphorylation of PKCdelta were blocked by a low concentration of rottlerin, whereas the effects of insulin on other PKC isoforms were not. This selective blockade of PKCdelta by rottlerin also inhibited insulin-induced translocation of glucose transporter 4 (GLUT4), but not glucose transporter 3 (GLUT3), and significantly reduced the stimulation of glucose uptake by insulin. When overexpressed in skeletal muscle, PKCdelta and PKCdelta were both active. Overexpression of PKCdelta induced the translocation of GLUT4 to the plasma membrane and increased basal glucose uptake to levels attained by insulin. Moreover, insulin did not increase glucose uptake further in cells overexpressing PKCdelta. Overexpression of PKCdelta did not affect basal glucose uptake or GLUT4 location. Stimulation of glucose uptake by insulin in cells overexpressing PKCdelta was similar to that in untransfected cells. Transfection of skeletal myotubes with dominant negative mutant PKCdelta did not alter basal glucose uptake but blocked insulin-induced GLUT4 translocation and glucose transport. These results demonstrate that insulin activates PKCdelta and that activated PKCdelta is a major signaling molecule in insulin-induced glucose transport.

Acetophenones↗
PubMed1999

[A study of hypertriglyceridemia occurring in patients with chronic hepatitis C during administration of interferon beta].

The prevalence and risk factors of hypertriglyceridemia during the administration of interferon (IFN) were examined in 78 patients with chronic hepatitis C who were treated with 6 MU of IFN-beta once or 3 MU of IFN-beta twice a day for 6 weeks. Hypertriglyceridemia (serum triglyceride (TG) above 150 mg/dl) was found before the start of IFN treatment in 9% of the patients. During the administration of IFN, elevation of serum TG above 150 mg/dl was found in 82% of patients. In addition, serum TG level exceeded 500 mg/dl at least once during the administration of IFN in 13% of patients. On stepwise multiple regression analysis, three risk factors, high serum TG value before the administration of IFN, high ALT value before the administration of IFN, and divided administration of IFN-beta twice daily were found to be associated with hypertriglyceridemia during IFN administration.

Adult↗
PubMed1999

[Prevalence of TT virus in patients with fulminant hepatic failure in Japan].

A novel virus(TTV) was isolated from patients with post-transfusion hepatitis of unknown etiology. We studied the prevalence of TTV in 26 patients with fulminant hepatic failure. Serum samples at admission from seven(27%) of the 26 patients were positive for TTV. TTV was also detected in 29(27%) of the 106 healthy blood donors. There were no differences in the positive rate between patients with fulminant hepatic failure and healthy blood donors. There were no differences in clinical findings, or duration from onset to coma in patients with and without TTV. However, the outcome of the patients with TTV was significant worse than those without. TTV may not cause severe hepatitis such as fulminant hepatic failure.

Adult↗
PubMed1999

Clinical usefulness of scintigraphy with 99mTc-galactosyl-human serum albumin for prognosis of cirrhosis of the liver.

UNLABELLED: Scintigraphy with 99mTc-diethylenetriamine pentaacetic acid-galactosyl-human serum albumin (99mTc-GSA) is useful for evaluating hepatic functional reserve. We assessed the clinical usefulness of this technique, including its value in establishing a prognosis, in patients with cirrhosis of the liver. METHODS: Scintigraphy with 99mTc-GSA was performed in 10 healthy subjects, 42 patients with chronic hepatitis and 158 patients with cirrhosis. Computer acquisition of gamma camera data were started just before the injection of 99mTc-GSA. Time-activity curves for the heart and liver were generated from regions of interest (ROIs) for the heart and the entire liver. A receptor index was calculated by dividing the radioactivity of the liver ROI by that of the liver-plus-heart ROI 15 min after the injection. An index of blood clearance was calculated by dividing the radioactivity of the heart ROI at 15 min by that of the heart ROI at 3 min. RESULTS: The median receptor index was lower in patients with cirrhosis than in patients with chronic hepatitis or in healthy subjects, and the median index of blood clearance was higher. The receptor index was significantly lower when a complication (varices, ascites) was present. The index of blood clearance was significantly higher when a complication (varices and ascites) was present. Correlation of the two indices with classic indicators for functional reserve was significant. On the basis of the receptor index, the patients with cirrhosis were divided into two groups of roughly equal size: group A, receptor index over 0.85, and group B, receptor index 0.85 or less. On the basis of the index of blood clearance, the patients with cirrhosis were divided into two groups of roughly equal size: group A, index of blood clearance < 0.70, and group B, index of blood clearance > or = 0.70. The cumulative survival rates were lower in group B than in group A. CONCLUSION: Scintigraphy with 99mTc-GSA is clinically useful, especially in establishing the prognosis of patients with cirrhosis of the liver.

Ascites↗
PubMed1999

Gastroprotection by Liu-Jun-Zi-Tang (TJ-43): possible mediation of nitric oxide but not prostaglandins or sulfhydryls.

Liu-Jun-Zi-Tang (TJ-43), a herbal medicine exerting gastroprotective action, was examined for its mechanism of action in rats. TJ-43 significantly inhibited gastric mucosal damage caused by absolute ethanol at doses over 500 mg/kg in a dose-dependent way. Pretreatment with indomethacin or with N-ethylmaleimide did not affect the gastroprotective effect of TJ-43. However, pretreatment with NG-nitro-L-arginine partially but significantly reversed the protective effect of this drug. These findings suggest that the gastroprotective effect of TJ-43 occurs partly through nitric oxide but not through prostaglandins or sulfhydryls.

Animals↗
PubMed1999

Effect of culture conditions on morphological changes of Helicobacter pylori.

The morphological conversion of Helicobacter pylori from the spiral form to the coccoid form may be the expression of a transitory adaptation to an unsuitable environment. The mechanism(s) of this conversion are not clear. In this study, we examined whether the morphological conversion of H. pylori is affected by various culture conditions, such as oxygen concentration, pH, temperature, or the presence of beta-cyclodextrin. H. pylori (NTCC11916) was cultured on Brucella agar, followed by culture in Brucella broth containing 1% agar under several conditions. Morphological conversion of individual H. pylori on the agar plate was investigated with time after incubation under phase contrast microscopy. When H. pylori was inoculated in Brucella broth containing beta-cyclodextrin, the spiral form of the organism was observed even after 6 days of incubation under standard culture conditions: 37 degrees C, pH 7, and microaerobic atmosphere (5% O2/10% CO2/85% N2) (control). The morphological conversion of H. pylori was completed on day 3 in an aerobic atmosphere (20% O2 supply) and on day 2 in an undermicroaerobic atmosphere (<0.1% O2). Its complete morphological conversion was observed at pH 8 on day 5 and at pH 4 on day 6. All of the H. pylori (100%) incubated at 20 degrees or 42 degrees C had converted from the bacillary to the coccoid form on day 4. Conditioned medium without beta-cyclodextrin caused complete conversion on day 5. These results suggest that oxygen concentration, pH, temperature, and beta-cyclodextrin may be related to the H. pylori morphological conversion from the bacillary to the coccoid form.

Culture Media↗
PubMed1999

[Position of venous outflow: a crucial aspect in flaps with 2 opposed pedicles. Application to the cutaneous delay phenomenon. Experimental study with rats].

In the present study, the authors decided to focus on the effect of the venous outflow location in the survival of a flap with a choke vessels barrier by means of a rat bipedicled ventral island flap. In a first experiment, the extent of flap necrosis was examined in three experimental groups: group 1, alternate vein and artery ligation (n = 5); group 2, unilateral artery ligation (n = 5); group 3, unilateral pedicle ligation (n = 5). Less than 10% necrosis occurred in group 1; 28% in group 2 and 33% in group 3. In a second experiment we applied the first results to the delay phenomenon. 10 rats were divided into 2 groups: group 4, primary ligation of a complete pedicle on one side; group 5, primary alternate vein and artery ligation and the flaps were raised 21 days later. We observed 20% necrosis in group 4 and only 4% in group 5. The data of the first experiment indicate that a vein remaining near the artery can be a dramatic obstacle to the efficiency of choke vessels. The second experimental study shows the superiority of primary selective ligation in the delay phenomenon.

Animals↗
PubMed1999

Significant role of apoptosis in type-1 autoimmune hepatitis.

We used the terminal deoxyribonucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick-end labeling (TUNEL) method to detect apoptosis, and immunohistochemical staining for molecules related to apoptosis, a marker of cell proliferation, and surface markers of lymphocytes to examine 20 patients with autoimmune hepatitis (AIH). Confluent hepatic necrosis was frequently found, in which rosette formation of hepatocytes and ductular proliferation were common. TUNEL staining and staining for Lewis Y antigen, Bax protein, and Fas antigen were found in biliary epithelial cells in bile ducts and proliferating atypical bile ductules in regions of confluent necrosis with severe lymphocytic infiltration. TUNEL staining and staining for Lewis Y antigen and Bax protein were found in rosette-forming hepatocytes. Many hepatocytes in lobules without injury were stained for proliferating cell nuclear antigen (PCNA). bcl-2 oncoprotein was found in many lymphocytes surrounding proliferating atypical bile ductules and rosette-forming hepatocytes in regions of confluent necrosis, in which CD20 and OPD 4 were found. Apoptosis of both hepatocytes in rosette arrangement and biliary epithelial cells in bile ducts and proliferating atypical bile ductules may play a role in progression of AIH as well as confluent hepatic necrosis.

Adult↗
PubMed1999

Effects of antipsychotic drugs on extracellular dopamine levels in rat medial prefrontal cortex and nucleus accumbens.

The present study was designed to compare the effects of typical and atypical antipsychotic drugs on extracellular dopamine (DA) levels in the medial prefrontal cortex (mPFC) and the nucleus accumbens (NAC), using in vivo microdialysis with dual probe implantation in awake, freely moving rats. Amperozide (2 and 10 mg/kg), clozapine (5 and 20 mg/kg), and olanzapine (10 mg/kg), all of which are atypical antipsychotics, produced greater increases in extracellular DA levels in the mPFC than in the NAC. Olanzapine (1 mg/kg), risperidone (0.1 and 1 mg/kg), also an atypical antipsychotic, and S-(-)-sulpiride (25 mg/kg), a typical antipsychotic, produced comparable increases in extracellular DA levels in the mPFC and the NAC. S-(-)-sulpiride (10 mg/kg) and haloperidol (0.1 and 1 mg/kg), another typical antipsychotic, significantly increased extracellular DA levels in the NAC but not in the mPFC. The effects of the six antipsychotic drugs to increase extracellular DA levels in the mPFC relative to those in the NAC was positively correlated with the difference between their pKi values for serotonin (5-hydroxytryptamine, 5-HT2A) and DA-D2 receptors and was inversely correlated to their pKi values for D2 or D3 receptors, but was not for 5-HT2A receptors alone. These results are consistent with the hypothesis that the ability of antipsychotic drugs to produce a greater increase in prefrontal compared with NAC extracellular DA levels may be related, in part, to weak D2 and D3 receptor affinity relative to 5-HT2A receptor antagonism.

Animals↗
PubMed1999

Quantitative analysis and in situ localization of human telomerase RNA in chronic liver disease and hepatocellular carcinoma.

Telomerase is a specialized type of reverse transcriptase that catalyzes the synthesis and extension of telomeric DNA. High levels of telomerase activity have been detected in most hepatocellular carcinoma (HCC) tissues; very weak telomerase activity is, however, detected in approximately half of nontumorous chronic liver disease tissues. The purpose of this study was to investigate the possible source of this weak telomerase activity in these tissues using quantitative competitive reverse transcription (RT)-polymerase chain reaction (PCR) and in situ RT-PCR. Competitive RT-PCR indicated that the relative amount of human telomerase RNA (hTR) was significantly higher in chronic hepatitis or liver cirrhosis compared with the normal liver (p < 0.005), and in HCC compared with the normal liver (p < 0.001) and with chronic hepatitis or liver cirrhosis (p < 0.0001). In the normal liver tissue, hTR was detected by in situ RT-PCR in occasional sinusoidal cells and nuclei of occasional hepatocytes. In tumor-free liver or tumor-bearing liver, hTR was detected in sinusoidal cells, infiltrating lymphocytes, occasional proliferative bile ductal epithelial cells, and the nuclei of occasional hepatocytes. In HCC, hTR was detected in nuclei of all HCC cells as an intense signal and in sinusoidal cells. These results indicate that the amount of hTR increases in the nuclei of hepatocytes during hepatocarcinogenesis, and that the cells associated with the weak telomerase activity in approximately half of the nontumorous chronic liver lesions are mainly migrating lymphocytes and sinusoidal cells.

Adult↗
PubMed1998

Efficient and stable gene transfer following microinjection into nuclei of synchronized animal cells progressing from G1/S boundary to early S phase.

We examined the possible phase(s) of the cell cycle in which a foreign gene can be stably transferred to animal cells. DNA of the plasmid pSV2neo containing the neomycin-phosphotransferase gene was microinjected into the nuclei of NIH/3T3 cells synchronized by serum starvation and aphidicolin treatment. The frequency of neo(r)-transformation (expressed as a percentage of microinjected cells) was 6% at the G0 phase and increased with progression of the cell cycle to reach a peak of 76% at the G1/S boundary. When the cells started their growth from the G1/S following release from aphidicolin, the frequency increased or decreased in the parallel with the BrdU-labeling index. Furthermore we developed a simplified method in which asynchronously growing cells were treated with aphidicolin at 10 micrograms/ml fro 16 hrs without serum starvation and subjected to microinjection, and their growth was further induced in aphidicolin-free medium. Using five cell lines (BALB/3T3, BALB/MK-2, NRK, CHO-K1, and HeLa) and one primary culture of chicken embryo fibroblasts (CEF), a 3- to 7-fold increase in the frequency of neo(r)-transformation was consistently detected in aphidicolin-treated cells, compared to non-treated asynchronous cultures. The present study indicates that synchronized animal cells progressing from the G1/S boundary to the early S phase integrate the PSV2neo DNA into their chromosomes with high efficiency.

3T3 Cells↗