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T Higashi

Publications and source records attributed to T Higashi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Expression of a novel RNA-splicing factor, RA301/Tra2beta, in vascular lesions and its role in smooth muscle cell proliferation.

RA301/Tra2beta, a sequence-specific RNA-binding protein, was first cloned as a stress molecule in re-oxygenated astrocytes. In human vascular tissues, we have found enhanced RA301/Tra2beta expression in coronary artery with intimal thickening, and atherosclerotic aorta. Balloon injury to the rat carotid artery induced RA301/Tra2beta transcripts followed by expression of the antigen, which was detected in medial and neointimal vascular smooth muscle cells (VSMCs). In cultured VSMCs, hypoxia/re-oxygenation caused induction of RA301/Tra2beta and was accompanied by cell proliferation, both of which were blocked by the addition of either diphenyl iodonium, a NADPH oxidase inhibitor, PD98059, a mitogen-activated protein kinase kinase inhibitor, or antisense oligonucleotide for RA301/Tra2beta. Consistent with a link between RA301/Tra2beta and cell proliferation, platelet-derived growth factor also induced expression of RA301/Tra2beta in cultured VSMCS: These data suggest a possible role for RA301/Tra2beta in the regulation of VSMC proliferation, especially in the setting of hypoxia/re-oxygenation-induced cell stress.

Adolescent↗
PubMed2001

Studies on neurosteroids XIV. Levels of dehydroepiandrosterone sulfate in rat brain and serum determined with newly developed enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay (ELISA) of dehydroepiandrosterone sulfate (DHEAS), one of the neurosteroids, has been developed for measuring its brain and serum levels in rats without deconjugation. 11 alpha-Hemiglutaryloxy-DHEAS was newly synthesized, conjugated with bovine serum albumin (BSA), and immunized to rabbits for the production of anti-DHEAS antibodies. A bridge-heterologous ELISA system employing the sequential saturation method exhibited a high sensitivity with a midpoint of 100 pg. Although the antibody significantly cross-reacted with epiandrosterone sulfate, it easily discriminated the unconjugated steroids and pregnenolone sulfate, which is reported to exist in the brain at a much higher level when compared with DHEAS. The brain homogenate or serum was treated with hexane to remove the lipophilic compounds and purified with an OASIS HLB cartridge. The DHEAS levels were then determined by ELISA. The overall recovery rate through the pretreatment was a satisfactory and constant (81.8 +/- 3.4% for brain, 89.3 +/- 3.0% for serum, mean +/- standard deviation). This ELISA afforded a satisfactory serial dilution study and recovery test. The intra- and inter-assay coefficients of variation were lower than 13%, which showed the precision of the proposed method. The applied method showed that DHEAS was not detected in some brain samples and its levels were much lower than those previously reported and than its serum levels.

Animals↗
PubMed2001

T cell repertoire in primary biliary cirrhosis: a common T cell clone and repertoire change after treatment.

T cell repertoire was analyzed in three early-stage primary biliary cirrhosis (PBC) patients, using reverse transcription-polymerase chain reaction and single-strand conformation polymorphism. Multiple expanded clones were demonstrated in livers and peripheral blood lymphocytes (PBL) of all three patients. Comparison of the repertoire of different parts of the liver demonstrated the presence of common clones in various Vbeta families. Comparison of the repertoire between the liver and PBL demonstrated that both CD4 and CD8 T cell clones were expanded. Sequence analysis of complementarity determining region 3 of the expanded clones revealed that relatively conserved amino acids were utilized in each patient and that an identical CD4 T cell clone having Vbeta16 was present in all three patients. The number of expanded T cell clones in PBL decreased markedly after the treatment with prednisolone. These results suggest that common T cell clones may play a pathogenic role in PBC.

Anti-Inflammatory Agents↗
PubMed2001

High frequency of circulating HBcAg-specific CD8 T cells in hepatitis B infection: a flow cytometric analysis.

Viral antigen-specific T cells are important for virus elimination. We studied the hepatitis B virus (HBV)-specific T cell response using flow cytometry. Three phases of HBV infection were studied: Group A, HBeAg (+) chronic hepatitis; Group B, HBeAb (+) HBV carrier after seroconversion; and Group C, HBsAb (+) phase. Peripheral T cells were incubated with recombinant HB core antigen (HBcAg), and intracytoplasmic cytokines were analysed by flow cytometry. HBcAg-specific CD4 and CD8 T cells were identified in all three groups and the number of IFN-gamma-positive T cells was greater than TNF-alpha-positive T cells. The frequency of IFN-gamma-positive CD4 and CD8 T cells was highest in Group C, compared with Groups A and B. No significant difference in the HBcAg-specific T cell response was observed between Group A and Group B. The HBcAg-specific CD8 T cell response was diminished by CD4 depletion, addition of antibody against human leucocyte antigen (HLA) class I, class II or CD40L. Cytokine-positive CD8 T cells without HBcAg stimulation were present at a high frequency (7 of 13 cases) in Group B, but were rare in other groups. HBcAg-specific T cells can be detected at high frequency by a sensitive flow cytometric analysis, and these cells are important for controlling HBV replication.

Adult↗
PubMed2001

Motoneuron pool excitability of hemiplegic patients: assessing recovery stages by using H-reflex and M response.

OBJECTIVES: To compare the excitability of the motoneuron pools of both the spastic and the unimpaired sides of patients with hemiplegia with a new method by using H-reflexes and M responses. The method determines the ratio of the developmental slope of the H-reflex (Hslp) to the slope of the M response (Mslp). We also examined the relation between the Brunnstrom stages and the Hslp/Mslp. DESIGN: Experiment. SETTING: Electrophysiologic experimental laboratory in a Japanese medical school. PATIENTS: Fifteen hemiplegic patients (9 men, 6 women; age range, 48-71yr; mean, 60yr) with spasticity caused by a stroke. INTERVENTIONS: The subject was instructed to relax while seated in a reclining chair with his foot fixed on an immobile pedal. After the soleus H-reflex and M responses on one side were recorded, the same experimental procedures were carried out on the other side. MAIN OUTCOME MEASURES: Hslp/Mslp Brunnstrom stages. RESULTS: Hslp/Mslp had better predictive value than conventional indicators of motoneuron pool excitability. Hslp/Mslp appeared to be a better match for the bell-shaped pattern of the Brunnstrom stages. CONCLUSION: Hslp/Mslp is the preferred index for evaluating the motoneuron pool excitability of the spastic side of hemiplegic patients.

Aged↗
PubMed2001

Comparison of gene expression of cytokines mRNA in lungs of rats induced by intratracheal instillation and inhalation of mineral fibers.

To investigate whether the results of intratracheal instillation studies on mineral fibers reflect the findings obtained by long-term inhalation data on mineral fibers, we have examined gene expression of cytokines and pathological features in lungs induced by intratracheal instillation and inhalation of mineral fibers. Male Wistar rats were given a single intratracheal instillation of 2 mg alumina silicate refractory fiber (RF1) or potassium octatitanate whisker (PT1), and were sacrificed 4 wk after the fiber instillation. Long-term inhalation studies were also performed. In these, animals were exposed to fiber aerosol of RF1 or PT1 for 5 days/wk for 1 yr, and sacrificed after 1 yr of inhalation. Expression of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and transforming growth factor-beta1 (TGF-beta1) from lungs was observed by reverse-transcription polymerase chain reaction (RT-PCR). The expression of TNF-alpha, IL-6, and TGF-beta1 mRNA in PT1-exposed lung was significantly higher than for those exposed to RF1 in both intratracheal instillation and inhalation studies. Pathological findings revealed that mild pulmonary fibrosis was seen in the lungs after intratracheal instillation and inhalation of PT1 but not RF1. Similarities were observed not only in gene expression of cytokines but in pathological features between both studies. These data suggested that the results of intratracheal instillation reflect the findings obtained from long-term inhalation data.

Aluminum Silicates↗
PubMed2001

Inhibitory effects of barbiturates on nicotinic acetylcholine receptors in rat central nervous system neurons.

BACKGROUND: Neuronal nicotinic acetylcholine receptors (nAChRs) are widely expressed in the central and autonomic nervous systems. The authors have previously shown that depressant and convulsant barbiturates both inhibit the ganglion-type nAchRs in PC12 cells. However, the central and gangliontype receptors have different subunit composition and pharmacologic properties. In this study, the authors investigated the effects of thiopental, depressant [R(-)] and convulsant [S(+)] stereoisomers of 1-methyl-5 phenyl-5-propyl barbituric acid (MPPB) on neuronal nAChRs in the rat central nervous system to explore significance of these effects in barbiturate anesthesia. METHODS: Whole-cell currents were measured in acutely dissociated rat medial habenula (MHb) neurons by applying 10 or 100 microM nicotine in the absence or presence of thiopental 3-100 microM. Effects of R(-)- and S(+)-MPPB on the nicotine-induced current were also studied. RESULTS: Thiopental suppressed the nicotine-elicited inward current and accelerated the current decay dose-dependently at the clinical relevant concentrations. R(-)- and S(+)-MPPB both inhibited the nicotine-induced current dose-dependently without augmenting the current decay. There was no significant difference in the magnitudes of inhibition by R(-)- and S(+)-MPPB. CONCLUSIONS: Although thiopental suppressed the current mediated through native nAchRs in rat MHb neurons at the clinically relevant concentrations, the depressant and convulsant stereoisomers of MPPB both inhibited the current in the same extent. These findings are consistent with the results previously obtained in the ganglion-type receptors of PC12 cells and suggest that inhibition of nAChRs in MHb neurons is not directly relevant to the hypnotic or anticonvulsive actions of barbiturates.

Animals↗
PubMed2001

Nicorandil enhances cardiac endothelial nitric oxide synthase expression via activation of adenosine triphosphate-sensitive K channel in rat.

In the heart, nitric oxide activates an adenosine triphosphate (ATP)-sensitive K (K(ATP)) channel that is constructed of two subunits, i.e., an ATP-binding cassette protein sulfonylurea receptor (SUR2) and a pore-forming inward rectifier (Kir6.1 or 6.2). However, whether this K(ATP) channel affects nitric oxide activation is unknown. Our aim was to assess whether pharmacologic activation of the K(ATP) channel by nicorandil contributes to endothelial nitric oxide synthase (eNOS) levels. A total of 21 7-week old male Sprague-Dawley rats were used. Seven were treated by intraperitoneal injection of nicorandil at 3 mg/kg/d; seven were treated with intraperitoneal nicorandil at 3 mg/kg/d after glibenclamide at 12 mg/kg/d twice a day p.o.; and seven were left untreated (controls). At 24 h after treatment, blood pressure and heart rate were measured, and eNOS, SUR2, Kir6.1, and Kir6.2 mRNA levels and eNOS protein levels in the left ventricle were determined by reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. Nicorandil caused tachycardia without a change in blood pressure, whereas glibenclamide had no effect on the nicorandil-induced change in heart rate or on blood pressure. RT-PCR revealed that nicorandil increased the eNOS and SUR2 mRNA levels by 2.2- and 2.0-fold, respectively, (p < 0.01 versus control), and that these increases were completely inhibited by glibenclamide. A significant correlation was observed between eNOS and SUR2 mRNA levels in all experimental rats (r = 0.760, p < 0.001). However, Kir6.1 or 6.2 mRNA level was constant. Western blot analysis revealed that nicorandil caused a 1.6-fold increase in eNOS protein levels (p < 0.01 versus control). This increase was completely inhibited by glibenclamide. In conclusion, up-regulation of eNOS mRNA and protein levels by nicorandil, and inhibition of this upregulation by glibenclamide, were demonstrated in normotensive conscious rat hearts. Nicorandil appears to enhance cardiac eNOS expression via activation of a K(ATP) channel.

ATP-Binding Cassette Transporters↗
PubMed2001

Overexpression of latent transforming growth factor-beta 1 (TGF-beta 1) binding protein 1 (LTBP-1) in association with TGF-beta 1 in ovarian carcinoma.

Using the differential display method, latent transforming growth factor-beta 1 (TGF-beta 1) binding protein 1 (LTBP-1) mRNA was identified as one of the enriched mRNAs in ovarian carcinoma tissues after isolation of genes responsible for the development of ovarian cancer. Semi-quantitative reverse transcription (RT)-PCR analysis showed that expression of LTBP-1 and TGF-beta 1 mRNAs was much higher in both serous and mucinous adenocarcinomas than in their benign counterparts, including serous and mucinous cystadenomas and cystadenomas of low malignant potential (LMPs). Immunohistochemical analysis demonstrated that only proliferating benign adenoma cells were immunoreactive for both LTBP-1 and TGF-beta 1 proteins. In contrast, most serous and mucinous adenocarcinoma cells and their surrounding stroma were intensely immunoreactive for LTBP-1 and TGF-beta 1. LTBP-1 and TGF-beta 1 proteins, and their complex forms were identified in ovarian carcinoma cell lines and in their culture media by western blot analysis, suggesting these products were produced in ovarian carcinoma cells. RT-PCR analysis demonstrated that LTBP-1L, one of the LTBP-1 transcripts that has a strong activity in targeting the latent form of TGF-beta 1 to extracellular matrix (ECM), was predominantly expressed in ovarian carcinomas. Taken together, the results suggest that upregulation of LTBP-1 in ovarian carcinoma cells may have an important role in distributing TGF-beta1 in the stromal tissues surrounding carcinoma cells.

Adenocarcinoma, Mucinous↗
PubMed2001

Molecular dissection of alpha- and dense-core granule secretion of platelets.

Upon activation, platelets release many active substances stored in alpha- and dense-core granules. However, the molecular mechanisms governing the regulated exocytosis are not yet fully understood. We have established an assay system using streptolysin-O-permeabilized platelets to analyze the Ca2+-induced secretions of von Willebrand factor stored in alpha-granules and [3H]5-hydroxytryptamine (5-HT) in dense-core granules. Using the assay, we found that small GTPase Rab4 regulates alpha-, but not dense-core, granule secretion in platelets. Furthermore, we purified a cytosolic essential protein and currently are analyzing its function.

Blood Platelets↗
PubMed2001

Mechanisms of modulation of neuronal nicotinic receptors by substance P and OAG.

Substance P is known to modulate neuronal nicotinic acetylcholine receptors (nAChRs) in the sympathetic nervous system. There are two conflicting proposals for the mechanism of this effect, an indirect action mediated by protein kinase C (PKC) and a direct interaction with receptor subunits. We studied the mechanisms of this effect in PC-12 cells. Substance P enhanced the decay of the nicotine-induced whole cell current. This effect was fast in its onset and was not antagonized by guanosine 5'-O-(2-thiodiphosphate), a G protein blocker, or staurosporine, a nonselective PKC blocker. Staurosporine failed to reverse the inhibition by 1-oleoyl-2-acetyl-sn-glycerol (OAG), a synthetic diacylglycerol analog known to activate PKC. The inhibitory effects of the peptide and OAG were preserved in excised patches, but substance P applied to the extra patch membrane was ineffective in the cell-attached patch configuration. We conclude that substance P modulates neuronal nAChRs most likely by direct interactions with the receptors but independently from activation of PKC or G proteins and that PKC does not participate in modulation by OAG.

Animals↗
PubMed2001

Potential value of CML-Hb in predicting the progression of bone cysts in dialysis-related amyloidosis.

BACKGROUND/AIM: Carboxymethyllysine is one of the common advanced glycation end products in vivo. In a previous report, we were the first to describe the increase of circulating carboxymethyllysine-hemoglobin (CML-Hb) levels in hemodialysis patients, particularly in patients with dialysis-related amyloidosis (DRA). The aim of this study was to investigate the predictive value of CML-Hb in the progression of DRA using computed tomography images of 2-year or 3-year follow-up periods of patients with amyloid bone cysts at the hip joint. METHODS: Circulating CML-Hb levels were measured as previously reported, and computed tomography scanning was conducted from 1996 to 1998 or 1999 in 57 hemodialysis patients whose original renal disease had been confirmed to be nondiabetic. Patients who showed a new growth of cysts or a growth rate of 30% or more were classified as progressive cases, while the other patients were classified as nonprogressive cases. RESULTS: (1) The circulating CML-Hb levels showed a strong correlation with the DRA score by multiple regression analysis, and (2) patients with progression of amyloid cysts showed a significantly higher circulating CML-Hb level than patients without progression. CONCLUSION: Based upon these results, we conclude that measurement of circulating CML-Hb levels has a potential value in both judgment of the clinical state and prediction of progression of DRA in hemodialysis patients.

Amyloidosis↗
PubMed2001

Simultaneous determination of 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 in human plasma by liquid chromatography-tandem mass spectrometry employing derivatization with a Cookson-type reagent.

A rapid and highly sensitive LC-MS-MS method for simultaneous determination of 25-hydroxyvitamin D2 125(OH)D21 and 25-hydroxyvitamin D3 125(OH)D3] in human plasma has been developed using derivatization with a Cookson-type reagent, 4-12-(6,7-dimethoxy-4-methyl-3-oxo-3,4-dihydroquinoxalyl)ethyll-1,2,4-triazoline-3,5-dione (DMEQTAD). The derivatization with DMEQTAD significantly improved the ionization efficiencies of 25(OH)D2 and 25(OH)D3 with detection limits of 20 and 12.5 fmol (8 and 5 pg) per injection, respectively. The method employed two steps of solvent extraction but did not require chromatographic purifications for sample pretreatment. The determination was carried out by mass chromatography of the protonated molecular ions formed by atmospheric pressure chemical ionization operating in the positive-ion mode after the derivatization, and 25-hydroxyvitamin D4 was used as an internal standard. The intra-assay coefficients of variation were below 4.02 and 3.24% for 25(OH)D2 and 25(OH)D3, respectively, and the analytical recoveries of both compounds were quantitative. Assay linearity was obtained in the range of 0.05-1 ng per tube and the determination limit was 3 ng/ml for a 20 microl plasma aliquot, for each compound. The developed method was applied to plasma samples obtained from volunteers, two of whom had received vitamin D2 supplementation, and gave satisfactory results.

Adult↗
PubMed2001

An improved synthesis of butyl 4-[(4-amino-5-chloro-2-methoxybenzoyl)amino]-1-piperidineacetate (AU-224).

A new and facile route for the synthesis of the novel gastrointestinal prokinetic butyl 4-[(4-amino-5-chloro-2-methoxybenzoyl)amino]-1-piperidineacetate (1b), which exhibited potent gastro- and colon-prokinetic activities by oral administration without significant side effects, was established. The key intermediate, butyl 4-amino-1-piperidineacetate (16), was prepared from commercially available 4-amino-1-benzylpiperidine (2) in a high yield with four steps. Compound 1b was prepared by condensation of commercially available 4-amino-5-choloro-2-methoxybenzoic acid (7) with 16 in 84% yield. This improved synthetic route was appropriate for large-scale synthesis of 1b.

Gastrointestinal Agents↗
PubMed2001

Effects of zinc deficiency/zinc supplementation on ammonia metabolism in patients with decompensated liver cirrhosis.

Hepatic encephalopathy is one of the major complications in decompensated liver cirrhosis. The current study was conducted to clarify the mechanisms of zinc deficiency in liver cirrhosis and its involvement in hepatic encephalopathy via ammonia metabolism. Ten patients each with compensated or decompensated liver cirrhosis and 11 healthy volunteers were enrolled in the study. Serum zinc levels and its daily urinary excretion were measured, an oral zinc-tolerance test was performed to examine zinc malabsorption, and the effects of diuretics on zinc excretion and of zinc supplementation on ammonia metabolism in the skeletal muscle were studied. The mean serum zinc levels in patients with decompensated liver cirrhosis were found to be significantly lower than the levels in controls and patients with compensated liver cirrhosis. The serum zinc levels were inversely correlated with blood ammonia in the fasting state. In the oral zinc-tolerance test, the percent increase in serum zinc levels 120 and 180 min after ingestion was less in cirrhotic patients than in controls. A diuretic administration resulted in a significant reduction in serum zinc levels. An increased uptake of ammonia by and an increased release of glutamine from leg skeletal muscle after oral supplementation of zinc sulfate were evident. Taken together, zinc deficiency in decompensated cirrhotic patients appears to be due to low absorption and to high urinary excretion, for which excessive diuretic administration is, in part, responsible, and zinc supplementation might play an important role in the prevention of hepatic encephalopathy by activating glutamine synthetase.

Ammonia↗
PubMed2001

The trend in airborne asbestos concentrations at plants manufacturing asbestos-containing products in Japan.

In Japan, chrysotile is still permitted to use under the Ordinance on Prevention of Hazards due to Specified Chemical Substances. In recent years many countries have introduced a policy of prohibiting the use of asbestos, based on clinical and epidemiological studies. In light of this, it is important to evaluate the airborne asbestos concentrations in workplaces and also estimate the number of related disease cases in order to discuss the ban of asbestos use. The survey covered 528 workplaces in 145 plants and included 2795 asbestos handling workers from 1985 to 1998. These plants were belonging to the Japan Asbestos Association (JAA) as member companies. In Japan, nearly all of the asbestos using manufacturing companies are members of JAA. In our study, all of the workplaces were divided under each separate manufacturing process and classified into 3 categories of Control Classes. Of the 454/528 (86.0%) workplaces classified as Control Class 1 are improved to 376/378 (99.5%). Though in the cases of small enterprises, other factors such as a shift in product lines, and the economic recession, as well as efforts, contributed to improvements in working conditions. JAA recommended self-administered concentrations of 1.0 f/ml (compatible to <0.3 f/ml in personal exposure level) in 1991 to promote further improvements of the work environment. From this point of view, exposure limits can almost be technically achieved in Japan, and it is expected that asbestos related disease could be expected to decrease in 20 to 30 years later. This survey will become basic material for verifications whether we could control asbestos related diseases enough in such well-controlled work environment.

Air Pollutants, Occupational↗
PubMed2001

[Blood concentrations and side effects of tacrolimus in a living renal transplantation].

In a living renal transplantation, the recipients are administered an immunosuppressive agent preoperatively. The drug exhibits a high incidence of side effects of special note. We examined the side effects of tacrolimus to evaluate the postoperative management of living renal transplantation. Hypertension, hyperglycemia, tachycardia and chest pain were found as the side effects. The blood concentration should be measured frequently to maintain the effective blood concentration and to prevent the side effect.

Adult↗