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T Ide

Publications and source records attributed to T Ide.

At least 109 records · Page 6Linked to original sources
PubMed1999

Ubiquitin stress response in postischemic hippocampal neurons under nontolerant and tolerant conditions.

Ubiquitin, an essential protein in nonlysosomal proteolytic system, is expressed after metabolic stress to the cell. The authors investigated stress response of ubiquitin in the hippocampus of the Mongolian gerbil after forebrain ischemia. The level of hippocampal ubiquitin was compared with that under ischemic tolerance induced by ischemic preconditioning. The authors also studied ubiquitin gene expression using in situ hybridization method. Transient ischemia resulted in consumption of free ubiquitin and an increase of multiubiquitin chains. These changes were transient in the hippocampus outside of the CA1 region where neurons survived, whereas it was persistent in the CA1 region where neurons were destined to die after ischemia. Under tolerant condition, subsequent ischemia provoked rapid recovery and further increase of free ubiquitin. The signal of ubiquitin messenger ribonucleic acid was continuously detected after ischemia, not only under tolerant conditions, but without tolerance induced by preconditioning. Thus, ubiquitin stress response takes place, at least at a transcriptional level, in dying CA1 neurons. Under tolerant conditions, however, subsequent ischemia in the CA1 region induces the stress response of ubiquitin up to the translational level, leading to the rapid restoration of protein synthesis and to eventual neuronal survival.

Animals↗
PubMed1999

Immunohistochemical detection of human telomerase reverse transcriptase in normal mucosa and precancerous lesions of the stomach.

Telomerase activity confers cell immortality through stabilization of the chromosome, participating in the development of a majority of human cancers. Human telomerase reverse transcriptase (TERT) has been identified as a catalytic subunit of telomerase, and is overexpressed in most gastric carcinomas. We immunohistochemically examined the expression of TERT in normal gastric mucosa and candidate precancerous lesions such as intestinal metaplasia and adenoma. In non-neoplastic gastric mucosa including intestinal metaplasia and normal fundic mucosa, weak but significant expression of TERT was detected in nuclei of epithelial cells located in the lower two-thirds of the glands (wider than the proliferative zone). The telomerase activity was found in a half of gastric adenomas, whose levels of the activity were about 10% of those in gastric carcinomas. TERT protein was expressed in the nuclei of the adenoma cells at moderate levels, that were not necessarily comparable with the telomerase activities. These findings overall suggest that TERT expression may be one of the prerequisites for telomerase activation in an early stage of stomach carcinogenesis.

Adenoma↗
PubMed1999

Intraspousal transmission of GB virus C/hepatitis G virus in an hepatitis C virus hyperendemic area in Japan.

OBJECTIVE: An immunoassay for antibodies against an hepatitis G virus (HGV) protein (anti-E2) was recently developed that might serve as a useful marker for diagnosing recovery from HGV infection. METHODS: We investigated the intraspousal transmission of GB virus C/hepatitis G virus (GBV-C/HGV) using both reverse transcription hemipolymerase chain reaction (RT-hemi-PCR for the 5' untranslated region) and a recently developed anti-E2. RESULTS: Thirty-two GBV-C/HGV-infected index subjects were selected from an hepatitis C virus hyperendemic area in Japan. Of the 32 subjects, seven (6.4%) were GBV-C/HGV RNA-positive, 24 (21.8%) were anti-E2-positive, and one (0.9%) was both GBV-C/HGV RNA- and anti-E2-positive. Among the 32 spouses of these subjects, GBV-C/HGV RNA, anti-E2, and both GBV-C/HGV RNA and anti-E2 positivity were detected in 0, 6, (18.8%), and one (3.1%) spouses, respectively (the total prevalence of GBV-C/HGV was 7 spouses [21.9%]). Thus, the intraspousal transmission of GBV-C/HGV was undeniable in these seven couples. The respective positive rates of 175 sex- and age-matched controls were 7 (4.0%), 26 (14.9%), and 0 (the total prevalence of GBV-C/HGV was 34 [19.4%]). No significant difference in positive rates was observed between the subjects/spouses and the controls. Five spouses among the seven couples who were positive for any of GBV-C/HGV markers had parenteral risk factors such as blood transfusion, acupuncture, and major surgery. CONCLUSION: Based on these observations, we cannot draw a definitive conclusion that intraspousal transmission of GBV-C/HGV had occurred among these seven couples.

Aged↗
PubMed1999

Energy conservation by the H2:heterodisulfide oxidoreductase from Methanosarcina mazei Gö1: identification of two proton-translocating segments.

The membrane-bound H2:heterodisulfide oxidoreductase system of the methanogenic archaeon Methanosarcina mazei Gö1 catalyzed the H2-dependent reduction of 2-hydroxyphenazine and the dihydro-2-hydroxyphenazine-dependent reduction of the heterodisulfide of HS-CoM and HS-CoB (CoM-S-S-CoB). Washed inverted vesicles of this organism were found to couple both processes with the transfer of protons across the cytoplasmic membrane. The maximal H+/2e- ratio was 0.9 for each reaction. The electrochemical proton gradient (DeltamicroH+) thereby generated was shown to drive ATP synthesis from ADP plus Pi, exhibiting stoichiometries of 0.25 ATP synthesized per two electrons transported for both partial reactions. ATP synthesis and the generation of DeltamicroH+ were abolished by the uncoupler 3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile (SF 6847). The ATP synthase inhibitor N,N'-dicyclohexylcarbodiimide did not affect H+ translocation but led to an almost complete inhibition of ATP synthesis and decreased the electron transport rates. The latter effect was relieved by the addition of SF 6847. Thus, the energy-conserving systems showed a stringent coupling which resembles the phenomenon of respiratory control. The results indicate that two different proton-translocating segments are present in the H2:heterodisulfide oxidoreductase system; the first involves the 2-hydroxyphenazine-dependent hydrogenase, and the second involves the heterodisulfide reductase.

Adenosine Triphosphate↗
PubMed1999

Effect of dietary fats differing in degree of unsaturation on gene expression in rat adipose tissue.

To test the possibility that the type of dietary fat affects the expression of proteins involved in adipose tissue metabolism, levels of mRNA for lipoprotein lipase, leptin, glucose transporter 4, and uncoupling protein in adipose tissues were compared among rats fed a low-fat diet (2% safflower oil), and high-fat diets containing 20% saturated fat (palm oil) or unsaturated fat rich in linoleic acid (safflower oil) for 3 weeks. High-fat diets decreased the lipoprotein lipase mRNA level in epididymal but not in perirenal white adipose tissue, but increased it in brown adipose tissue. Leptin gene expression in perirenal white adipose tissue was significantly higher in rats fed high-fat diets than in those fed a low-fat diet. High-fat diets failed, however, to alter this parameter in epididymal white adipose tissue and interscapular brown adipose tissue. mRNA levels of glucose transporter 4, both in epididymal and perirenal white adipose tissues, were lower in rats fed high-fat diets than in those fed a low-fat diet. Uncoupling protein gene expression in interscapular brown adipose tissue was 2-3 times higher in rats fed high-fat diets than in those fed a low-fat diet. The abundance of mRNAs for lipoprotein lipase, leptin, glucose transporter 4 and uncoupling protein was, however, comparable between rats fed diets high in safflower and palm oil. We concluded that the high-fat diet influences gene expression of adipose tissue in a site-specific manner. The difference in the degree of unsaturation of dietary fats is rather irrelevant in modifying the level of mRNAs for proteins related to energy metabolism and expenditure in adipose tissue.

Adipose Tissue↗
PubMed1999

Characterization of human immunodeficiency virus type 1 strains resistant to the non-nucleoside reverse transcriptase inhibitor RD4-2217.

The non-nucleoside reverse transcriptase (RT) inhibitor RD4-2217 is a thiadiazole derivative that has proved to be a highly potent and selective inhibitor of human immunodeficiency virus type 1 (HIV-1) replication in vitro. In this study we examined genotypic and phenotypic characteristics of RD4-2217-resistant mutants that have been obtained by serial passage of HIV-1 in MT-4 cells in the presence of increasing concentrations (0.05, 0.25, 1 and 10 microM) of the compound. The strains obtained, III(B/2217RE/0.05) and III(B/2217RE/0.25,) were two- and 15-fold resistant to RD4-2217, respectively, whereas III(B/2217RE/1) and III(B/2217RE/10) displayed 161- and >238-fold resistance, respectively. Both III(B/2217RE/1) and III(B/2217RE/10) had two amino acid substitutions, V1891 and T2401, in the RT. Furthermore, RD4-2217 did not inhibit the replication of an HIV-1 molecular clone, which had the same mutation, at concentrations up to 10 microM, indicating that the V1891 plus T2401 mutation confers high-level resistance to RD4-2217. Interestingly, the replicability of III(B2217RE/1) and III(B/2217RE/10) appeared to be lower than that of wildtype III(B) in MT-4 cells, suggesting that the V1891 plus T2401 mutation may impair the enzymatic activity of HIV-1 RT.

Anti-HIV Agents↗
PubMed1999

A collagen network formation effector from leaves of Premna subscandens.

As a part of the search for biologically active plant products, M cells, which form a collagen fiber network in vitro after a prolonged culture period, were used. The n-BuOH-soluble fraction of a methanol extract of leaves of Premna subscandens exhibited promotion of collagen network formation by M cells. Extensive isolation work guided by a bioassay afforded a phenylethanoid, acteoside, as an active compound.

Cell Line↗
PubMed1999

pH-dependent fusion of synaptosomal membrane studied by fluorescence quenching method.

We have found that both the synaptic vesicles (SV) and synaptic plasma membrane vesicles (SPM) have an activity to fuse with phosphatidylcoline/phosphatidylserine liposomes in a pH-dependent manner. The activity increases with decreases in extravesicular pH. At a pH lower than 4.0, the activity is almost steady at its maximum value, and there was a rapid drop around pH 5.5. The pH-dependent fusion was inhibited by proteolysis with trypsin; hence, at least in part, some membrane proteins play an important role in these pH-dependent fusion processes. To find specific markers, we screened various protein modifiers and found that anion channel blockers, stilbene derivatives (DIDS and SITS) and glibenclamide, affected the fusion process. DIDS and SITS decreased the fusion activity with an IC50 of 180 and 300 microM, respectively, whereas glibenclamide, on the contrary, increased it. From the results of an autoradiogram using 3H-tagged DIDS, a 30 kDa DIDS-binding protein was identified in the synaptic plasma membrane, which is possible to be responsible for the pH-dependent fusion.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1999

Dietary phospholipid-dependent reductions in gene expression and activity of liver enzymes in fatty acid synthesis in fasted-refed rats.

The effects of dietary soybean phospholipid, its hydrogenation product and safflower phospholipid on gene expression and the activity of hepatic enzymes in fatty acid biosynthesis were examined in fasted-refed rats. Phospholipid composition of soybean phospholipid and its hydrogenation product were the same, but the hydrogenation product contained negligible amounts of unsaturated fatty acids. Among phospholipid classes, lysophosphatidylcholine and phosphatidylinositol proportions were slightly higher in safflower phospholipid than in soybean phospholipid or its hydrogenation product. Rats were fasted for 2 d and refed a fat-free diet or a diet containing 4% fatty acids either as soybean oil or various phospholipid preparations for 3 d. Compared to the fat-free diet, the soybean oil diet only slightly decreased specific, but not total hepatic fatty acid synthetase and malic enzyme activity, and it was totally ineffective in modulating glucose 6-phosphate dehydrogenase and pyruvate kinase activity under our experimental conditions. The diets containing phospholipids, however, markedly decreased the activity of these enzymes. The extent of reduction was somewhat attenuated with hydrogenated soybean phospholipid as compared with soybean and safflower phospholipids. Dot and Northern blot hybridization using specific cDNA probes showed that, compared to a fat-free diet, diets containing phospholipids profoundly decreased the hepatic mRNA levels of enzymes in fatty acid synthesis. Soybean oil, however, only marginally affected these parameters. Hepatic mRNA levels for enzymes correlated well with enzyme activity. Dietary phospholipids therefore appear to have decreased enzyme activity in fatty acid synthesis primarily by suppressing the mRNA levels of these enzymes. Compared to soybean oil, hydrogenated soybean phospholipid is still effective in decreasing the activity and mRNA level of enzymes in fatty acid synthesis. Therefore, it is difficult to ascribe the potent physiological activity of phospholipid in reducing fatty acid synthesis entirely to polyunsaturated fatty acid moiety.

Animals↗
PubMed1999

Effect of dietary sesamin on metabolic fate of an exogenous linolelaidic acid in perfused rat liver.

To estimate the relative significance of exogenous and endogenous fatty acid substrates in decreasing hepatic triacylglycerol secretion after sesamin feeding, livers from rats fed diets supplemented with and without sesamin (sesamin: episesamin, 1:1, w/w) were perfused in the presence and absence of an exogenous di-trans isomer of linoleic acid (linolelaidic acid, trans,trans-9,12-octadecadienoic acid). Both exogenous trans fatty acid and dietary sesamin, as compared with respective controls, resulted in a marked increase in hepatic ketogenesis; however, the beta-hydroxybutyrate to acetoacetate ratio was elevated by exogenous fatty acid and decreased by dietary sesamin. On the other hand, hepatic secretions of triacylglycerol, phospholipid and cholesterol were markedly lowered in rats fed sesamin, especially when exogenous fatty acid substrate was provided. The relative significance of the exogenous fatty acid was observed in the dietary sesamin-induced decrease in hepatic secretion of triacylglycerol. These results suggest that increased fatty acid oxidation by dietary sesamin, as reflected by enhanced ketone body production, leads to decreased partition of fatty acid substrates to the esterification pathways, and this in turn reduces the synthesis and secretion of triacylglycerol. The altered metabolism of exogenous fatty acids in the liver was therefore a major determinant for the synthesis and secretion of triacylglycerol.

Animals↗
PubMed1999

Simple, rapid, quantitative, and sensitive detection of telomere repeats in cell lysate by a hybridization protection assay.

BACKGROUND: Detection of telomere repeats by Southern hybridization of genomic DNA is time consuming, and the reading of a mean terminal restriction fragment (TRF) length from a smear pattern of an autoradiogram can be inaccurate. We developed a hybridization protection assay (HPA) for telomere repeats. METHODS: We heated 5 microL of DNA solution or 10 microL of cell or tissue lysate at 95 degrees C for 5 min, mixed it with 100 microL of hybridization solution containing 3 x 10(6) relative light units of acridinium ester-labeled probe, and incubated the mixture for 20 min at 60 degrees C. We then added 300 microL of selection buffer and incubated the mixture for 10 min at 60 degrees C to differentially hydrolyze unhybridized probe. Chemiluminescence was measured for 2 s per tube. RESULTS: The amount of telomere repeats was assayed by HPA within linearity from 10 to 3000 ng of purified genomic DNA or from 1000 to 100 000 cell equivalents of lysate. To normalize the amount of DNA in lysate, the amount of Alu sequence was measured by HPA. A ratio of telomere to Alu (TA ratio) = 0.01 corresponded to approximately 2 kbp of mean TRF length determined by Southern blotting in cultured fibroblast and colorectal tissue samples. The TA ratio decreased from 0.06 to 0.02 with increasing division age from 30 to 90 population doubling levels of cultured human fetal fibroblasts. The assay required approximately 45 min from collection of cell or tissue samples. CONCLUSIONS: The amount of telomere repeats was quantitatively measured by HPA in 10 ng of sheared genomic DNA or in the lysate of 1000 cells. This method is simple, rapid, quantitative, sensitive, and applicable to the measurement of telomere repeats in clinical samples such as needle biopsy specimen or as few as 1000 cells in body fluid or washings.

DNA↗
PubMed1999

Quantitative reevaluation of telomerase activity in cancerous and noncancerous gastrointestinal tissues.

Telomerase activity has been examined extensively in a variety of human cancerous and noncancerous tissues. However, it was sometimes difficult to measure telomerase activity quantitatively with the methods used and in the tissues examined. We examined telomerase activity quantitatively in gastrointestinal tissues by using the hybridization protection assay combined with the telomeric repeat amplification protocol (TRAP) to assess the diagnostic utility of measuring telomerase activity and to determine the relationship between telomerase activity and human telomerase reverse transcriptase (hTERT) expression. We report here that (i) polymerase chain reaction (PCR) inhibitors in the tissue extracts used for the telomerase assay were practically nullified by using tissue extract at 0.1 microg of protein/assay; (ii) RNase activity in tissue extracts should be blocked with 0.5 U of RNase inhibitor/microg tissue protein for the quantitative telomerase assay; (iii) no inhibitors of telomerase were found in tissue extracts other than RNase and PCR inhibitors (iv) higher telomerase activity in cancerous tissue than in noncancerous tissue from the same patients was observed in both gastric and colorectal tissues, but the telomerase activity varied from low to high levels in cancerous tissues, and it was not practical to set a general cut-off level for cancer diagnosis; (v) hTERT was expressed in both cancerous and noncancerous tissues, and (vi) the telomerase activity levels were generally lower than expected from the hTERT expression levels, suggesting posttranscriptional regulation of expression of telomerase activity.

Adenocarcinoma↗
PubMed1998

Expressional changes in alternative splicing affecting genes during cell passage of human diploid fibroblasts.

Normal human diploid cells have a limited proliferative lifespan in in vitro cultures. Changes in gene expression have been examined for understanding control mechanisms of limited proliferative lifespan. and enhanced expression of growth suppressing genes such as p21 was reported in late-passaged cells. We screened genes which were expressed preferentially in mid-passaged cells by the differential plaque screening of the subtracted cDNA libraries prepared from young, life-extended, and immortalized SV40-transformed human fibroblasts. Among isolated clones, ASF/SF2, which was known to affect alternative splicing, was expressed in normal fibroblasts with a peak at mid-passage. Relative expression levels of SC35 and hnRNPA1, which are also known to affect alternative splicing, was also highest at mid-passage. Changes in alternative splicing at mid-passage, if it occurred, may play a crucial role in the process of cellular senescence.

Alternative Splicing↗
PubMed1998

Extra-chromosomal telomere repeat DNA in telomerase-negative immortalized cell lines.

We found novel extra-chromosomal telomere repeat (ECTR) DNAs in telomerase-negative immortalized KMST-6 cells, by staining these cells with a (TTAGGG)n probe using both cycling oligonucleotide-primed in situ synthesis and by fluorescence in situ hybridization. Relatively small amounts of ECTR DNAs were also observed in telomerase-negative VA13 and SUSM-1 cells, but not observed in telomerase-positive immortalized HeLa cells. The ECTR DNAs existed mainly in the nucleoplasm with a small amount in the cytoplasm. The nucleoplasm ECTR DNAs were co-stained with an antibody directed to the telomeric-repeat binding factor 1 (TRF1), suggesting that they exist as a complex with TRF1. In consistent with these cytological studies, Southern blot analysis showed the existence of small telomere repeat DNAs. The ECTR DNA may provide an insight into the elucidation of the mechanisms responsible for the maintenance of telomeres in telomerase-negative immortalized cells.

Cell Line↗
PubMed1998

A hVti1 homologue: its expression depends on population doubling levels in both normal and SV40-transformed human fibroblasts.

A cDNA clone was isolated by differential colony hybridization from a cDNA library prepared from life-extended SV40-transformed human fibroblasts. The clone, tentatively named N-10, was 1272 bp in length coding for 232 amino acids. Northern analysis revealed that the expression level of N-10 was increased in normal senescent and life-extended SV40-transformed fibroblasts than in their young counterparts but was not enhanced by growth arrest. The protein fused to GFP (green fluorescent protein) localized in cytoplasmic granule. Enforced expression of N-10 resulted in premature senescence in young fibroblasts. The deduced amino acid sequence of N-10 was identical to the recently reported hVti1 gene except in one amino acid: Asp24(GAC) was ours and Asn24 (AAC) was reported. Additional base differences were found, so we referred to our sequence as the hVti1 homologue. As hVti1 protein was suggested to be involved in the vesicle transport process, the homologue may be concerned with increased secretion of extracellular matrix and various cytokines associated with cellular senescence.

Carrier Proteins↗
PubMed1998

Comparative effects of alpha- and gamma-linolenic acids on rat liver fatty acid oxidation.

It has been reported that both n-3 and n-6 octadecatrienoic acids can increase hepatic fatty acid oxidation activity. It remains unclear, however, whether different enzymes in fatty acid oxidation show a similar response to n-3 and n-6 octadecatrienoic acids. The activity of hepatic fatty acid oxidation enzymes in rats fed an oil mixture rich in alpha-linolenic acid (18:3n-3) and borage oil rich in gamma-linolenic acid (18:3n-6) was therefore compared to that in rats fed an oil mixture rich in linoleic acid (18:2n-6) and a saturated fat (palm oil) in this study. Linseed oil served as the source of 18:3n-3 for the oil mixture rich in this octadecatrienoic acid and contained 30.6% 18:3n-3 but not 18:3n-6. Borage oil contained 25.7% 18:3n-6 and 4.5% 18:3n-3. Groups of seven rats each were fed diets containing 15% various fats for 15 d. The oxidation rate of palmitoyl-CoA in the peroxisomes was higher in rats fed a fat mixture rich in 18:3n-3 (3.03 nmol/min/mg protein) and borage oil (2.89 nmol/min/mg protein) than in rats fed palm oil (2.08 nmol/min/mg protein) and a fat mixture rich in 18:2n-6 (2.15 nmol/min/mg protein). The mitochondrial palmitoyl-CoA oxidation rate was highest in rats fed a fat mixture rich in 18:3n-3 (1.93 nmol/min/mg protein), but no significant differences in this parameter were seen among the other groups (1.25-1.46 nmol/min/mg protein). Compared to palm oil and fat mixtures rich in 18:2n-6, a fat mixture rich in 18:3n-3 and borage oil significantly increased the hepatic activity of carnitine palmitoyltransferase and acyl-CoA oxidase. Compared to palm oil and a fat mixture rich in 18:2n-6, a fat mixture rich in 18:3n-3, but not fats rich in 18:3n-6, significantly decreased 3-hydroxyacyl-CoA dehydrogenase activity. Compared to palm oil and a fat mixture rich in 18:2n-6, borage oil profoundly decreased mitochondrial acyl-CoA dehydrogenase activity, but a fat mixture rich in 18:3n-3 increased it. 2,4-Dienoyl-CoA reductase activity was significantly lower in rats fed palm oil than in other groups. Compared to other fats, borage oil significantly increased delt3,delta2-enoyl-CoA isomerase activity. Activity was also significantly higher in rats fed 18:2n-6 oil than in those fed palm oil. It was confirmed that both dietary 18:3n-6 and 18:3n-3 increased fatty acid oxidation activity in the liver. These two dietary octadecatrienoic acids differ considerably, however, in how they affect individual fatty acid oxidation enzymes.

Animals↗
PubMed1998

RD6-2198, a novel betain-type fluoroalkylated oligomer, inhibits the replications of human immunodeficiency virus type 1 and other enveloped viruses.

We have examined a novel betain-type fluoroalkylated oligomer, RD6-2198, for its inhibitory effects on the replication of human immunodeficiency virus type 1 (HIV-1) and other enveloped viruses, including herpes simplex virus types 1 and 2 (HSV-1 and HSV-2, respectively) and respiratory syncytial virus (RSV) in cell cultures. We have found that the compound is a potent and selective inhibitor of these viruses. RD6-2198 inhibited the replication of HIV-1IIIB at a concentration of 0.85 microg/ml with a selectivity index greater than 59 in MT-4 cells. Furthermore, its 50% effective concentration (EC50) values for HSV-1, HSV-2 and RSV, were 0.51, 0.94 and 3.0 microg/ml, respectively. We found that the RD6-2198 suppressed the gp120-CD4 interaction (as monitored by an enzyme-linked immunosorbent assay (ELISA) method). RD6-2198 also inhibited the binding of anti-gp120 monoclonal antibody to gp120 expressed on MOLT-4/IIIB cells (MOLT-4 cells chronically infected with HIV-1IIIB). However, the compound did not inhibit the interaction of anti-CD4 antibody with CD4. These results suggest that RD6-2198 interacts with the viral envelope glycoprotein and thereby inhibits the viral adsorption process. In addition, RD6-2198 was also found to suppress the proliferation of MOLT-4/IIIB cells. When applied topically, RD6-2198 at a concentration of 10 mg/ml completely protected mice from an intravaginal HSV-2 infection.

Animals↗