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Biomedical subjects

T Suga

Publications and source records attributed to T Suga.

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

Impaired expression of brain natriuretic peptide gene in diabetic rats with myocardial infarction.

Accordingly, we induced streptozotocin diabetes in rats and evaluated the effects of ligating the coronary artery to produce myocardial infarct by analyzing hemodynamics and the expression of brain natriuretic peptide (BNP) messenger (m) RNA. Eight-week diabetic rats and age-matched nondiabetic rats underwent ligation of the coronary artery for 1 week. Left ventricular end-diastolic pressure (LVEDP) was not statistically different between diabetic rats (15+/-6 mmHg) and nondiabetic rats (13+/-9 mmHg) 1 week after coronary ligation, size of infarct, systolic blood pressure were also similar in both groups after coronary ligation. The BNP mRNA/beta-actin mRNA ratio in right ventricle of nondiabetic rats with MI was increased to 350+/-60%, however, in diabetic rats with MI, that was slightly increased to 200+/-50% (P < 0.01). The level of BNP mRNA in the left ventricle of diabetic rats with MI was not increased significantly (120+/-30% versus that in diabetic rats without MI), although that in left ventricle of nondiabetic rats with MI was increased to 280+/-40% versus nondiabetic rats without MI (P < 0.01). Cardiac BNP synthesis in diabetic rats completely reverted to control levels after insulin therapy.

Animals↗
PubMed1998

Idiopathic left ventricular tachycardia with block between purkinje potential and ventricular myocardium.

We performed radiofrequency current catheter ablation in a patient with idiopathic LV. While mapping the inferoapical LV septum during tachycardia, spontaneous termination of tachycardia was observed with block between Purkinje (P) potential and ventricular electrogram (P-V block). The cycle length of the tachycardia was associated with prolongation of P-P interval and P-V interval. P potential recording at this site was earliest and at very low amplitude during tachycardia. The radiofrequency current at this site was successful. These findings indicated that Purkinje fiber was a critical part of the tachycardia circuit. Ablation was successful at a site where both an earliest and low amplitude P potential was recorded during tachycardia, and where P-V block that was induced by catheter manipulation was observed during tachycardia.

Adult↗
PubMed1998

Suppression of apoptotic cell death progressed in vitro with incubation of the chorion laeve tissues of human fetal membrane by glucocorticoid.

In the trophoblast layer of the chorion laeve of human fetal membranes obtained by cesarean section at the month of normal parturition, cells with condensed nuclei could be observed by histochemical examination. Incubating fetal membranes at 37 degrees C in vitro in cultivation medium, the frequency of cells with condensed nuclei increased in the chorion laeve, associating with an increase in DNA fragmentation and the population of in situ TUNEL (terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-X nick end labeling) staining-positive cells. The progressed apoptotic cell death in the chorion laeve in vitro was suppressed by incubation of the tissue in the presence of glucocorticoids, cortisone or hydrocortisone, which was also demonstrated by DNA fragmentation analysis and in situ TUNEL staining. These results reveal that a substantial proportion of trophoblast cells in the chorion laeve of human fetal membranes are induced to undergo apoptosis at the end of pregnancy, and that the apoptosis progresses rapidly in vitro as the incubation period increases. It is suggested that certain hormones such as glucocorticoid, may be related to the regulation of the apoptosis in human fetal membranes.

Amnion↗
PubMed1998

Newly designed computer controlled knee-ankle-foot orthosis (Intelligent Orthosis).

The authors have developed a knee-ankle-foot orthosis with a joint unit that controls knee movements using a microcomputer (Intelligent Orthosis). The Intelligent Orthosis was applied to normal subjects and patients, and gait analysis was performed. In the gait cycle, the ratio of the stance phase to the swing phase was less in gait with the knee locked using a knee-ankle-foot orthosis than in gait without an orthosis or gait with the knee controlled by a microcomputer. The ratio of the stance phase to the swing phase between controlled gait and normal gait was similar. For normal subjects the activity of the tibialis anterior was markedly increased from the heel-off phase to the swing phase in locked gait. The muscle activities of the lower limb were lower in controlled gait than in locked gait. The ground reaction force in locked gait showed spikes immediately after heel-contact in the vertical component, and unusual patterns were observed at heel-contact in the sagittal and lateral component. Therefore, compared to locked gait, gait with the Intelligent Orthosis is smooth and close to normal gait from the viewpoint of biomechanics. Even in patients with muscle weakness of the quadriceps, control of the knee joint using the Intelligent Orthosis resulted in a more smooth gait with low muscle discharge.

Adult↗
PubMed1998

[Clinical assessment of contrast-enhanced ultrasonography for the diagnosis of gall bladder diseases].

We evaluated the efficacy of contrast-enhanced ultrasonography (CEUS) with intra-arterial injection of CO2 microbubbles in 37 cases of gall bladder diseases. CEUS clearly visualized arterial flow and vascularity in every lesions without debris and gave us the precise information of vascular structure for the differential diagnosis of gall bladder tumors. For example, highly bifurcated tumor vessels and strong enhancement was observed in gall bladder cancer and we could detect relatively strong enhancement along the lumen with lack of enhancement of Rokitansky-Aschoff sinus in localized-type adenomyomatosis. Though CEUS is now an invasive modality, it will enable us to understand the non-invasive modality such as color doppler imaging with intra-venous administration of microbubbles in the future.

Carbon Dioxide↗
PubMed1997

Mutation of the mouse klotho gene leads to a syndrome resembling ageing.

A new gene, termed klotho, has been identified that is involved in the suppression of several ageing phenotypes. A defect in klotho gene expression in the mouse results in a syndrome that resembles human ageing, including a short lifespan, infertility, arteriosclerosis, skin atrophy, osteoporosis and emphysema. The gene encodes a membrane protein that shares sequence similarity with the beta-glucosidase enzymes. The klotho gene product may function as part of a signalling pathway that regulates ageing in vivo and morbidity in age-related diseases.

Aging↗
PubMed1997

The mouse extracellular signal-regulated kinase 2 gene. Gene structure and characterization of the promoter.

ERK2 (extracellular-signal regulated kinase 2, also known as p42 mitogen-activated protein kinase) is an integral member of the mitogen-activated protein kinase cascade that is crucial for many cellular events such as proliferation and differentiation. Here, we determined the genomic organization of the Erk2 gene and characterized its promoter. The Erk2 gene spans over 60 kilobases, and the coding region is split into eight exons. In the coding region, exon-intron organization was exactly conserved between the two mouse genes for ERK2 and ERK1 except one junction shifted by one nucleotide. Primer extension and S1 nuclease analyses identified two major transcription start sites located at -219 and -223 relative to the translation start site. The 5'-flanking sequence lacked TATA box but contained a CCAAT box located approximately 60 base pairs upstream of transcription start sites. Sequencing of the 5'-flanking region also revealed potential cis-acting elements for multiple transcriptional regulatory factors including Sp1, zif268, Ets, CREB, and PuF sites. The promoter activity of the 5'-flanking region was examined using chloramphenicol acetyltransferase as a reporter gene. Transient transfection experiments using Chinese hamster ovary cells defined a maximal promoter activity in a 371-base pair region immediately upstream of the translation start site. Furthermore, we demonstrated, using mouse P19 embryonal carcinoma cells, that this 371-base pair sequence is likely to be sufficient to confer the transcriptional activation of the ERK2 promoter during the retinoic acid-induced differentiation of P19 cells.

Amino Acid Sequence↗
PubMed1997

Photoaffinity labeling of peroxisome proliferator binding proteins in rat hepatocytes; dehydroepiandrosterone sulfate- and bezafibrate-binding proteins.

To detect the cellular sites which directly interact with peroxisome proliferators (PPs) and mediate their inducing effect on peroxisomal enzymes in rat hepatocytes, two kinds of radiolabeled ligands, AD12 (7alpha-N-(4-azido-2-hydroxy-5-iodo[125I]benzyl)-aminomethyl-5-and rostene-3beta-ol-17-one-O-3-sulfate) and BZ5 (2-[p-[2-(4'-azido-3',5'-diiodo[125I]benzamido-2'-hydroxy)ethyl]phenoxy] -2-methylpropionic acid), were developed for photoaffinity labeling. These compounds were derivatives of dehydroepiandrosterone sulfate (DHEAS) and bezafibrate, respectively, with an azido group as the photoreactive functional group. Upon UV-irradiation following incubation with rat liver cytosol and nuclei, both the ligands effectively radiolabeled several proteins analyzed by SDS-polyacrylamide gel electrophoresis/radioluminography. When [125I]AD12 was used at a concentration of 0.2 microM, two cytosolic proteins with molecular masses of 55 and 28 kDa and a nuclear protein of 40 kDa were specifically labeled, as coincubation with a 1000-fold excess of DHEAS inhibited labeling. Photoaffinity labeling of the cytosolic 28-kDa protein was also affected by Wy-14,643, but not by unsulfated dehydroepiandrosterone or androsterone sulfate, consistent with our previous findings obtained in competitive binding studies of [3H]DHEAS-binding detected in rat liver cytosol (Yamada et al. (1994) Biochim. Biophys. Acta 1224, 139-146). On the other hand, [125I]BZ5 specifically labeled a cytosolic protein of 31 kDa, which was inhibited by coincubation with bezafibrate, clofibric acid and Wy-14,643, but not with DHEAS. Thus, [125I]AD12 and [125I]BZ5 labeled several proteins which recognized DHEAS and bezafibrate, respectively, in rat liver cytosol and nuclei, providing a useful means to investigate PP-binding proteins.

Affinity Labels↗
PubMed1997

Molecular cloning and expression of cDNAs encoding rat brain and liver cytosolic long-chain acyl-CoA hydrolases.

cDNAs encoding the long-chain acyl-CoA hydrolases (ACHs) from rat brain and liver, referred to as rBACH and rLACH1, respectively, were isolated and sequenced. The rBACH cDNA contained an open reading frame encoding a 338-amino acid polypeptide with a calculated molecular weight of 37,559, of which the deduced amino acid sequence matched partial amino acid sequences directly determined for peptides generated by tryptic digestion or CNBr cleavage of purified rBACH. The rLACH1 cDNA contained an open reading frame encoding a 343-amino acid polypeptide with a molecular weight of 38,240. When expressed in Escherichia coli, these cDNAs produced palmitoyl-CoA hydrolase activity and 44-kDa proteins with molecular masses similar to those of purified rBACH and rLACH1 (43 kDa). These expressed proteins and enzyme activity were immunoblotted and neutralized, respectively, by anti-rBACH or anti-rLACH1 antibodies. rLACH1 cDNA had 84 and 94% identity with rBACH cDNA at the nucleotide and amino acid levels, respectively. However, the 5'-end of the former cDNA which contained the N-terminal coding region of rLACH1 was entirely different from the corresponding region of rBACH cDNA, suggesting that these enzymes may be generated by alternative use of exons of the same gene. Northern blot analysis showed that ACH mRNA was expressed constitutively in the rat brain and testis, whereas its expression in the liver was inducible by treatment with the peroxisome proliferator. This study demonstrated the molecular diversity of ACH and suggested the presence of tissue-specific mechanisms to regulate the ACH gene expression.

Amino Acid Sequence↗
PubMed1997

Biologically active clerodane-type diterpene glycosides from the root-stalks of Dicranopteris pedata.

The molecular structure of the biologically active diterpene alcohol isolated previously from the root-stalks of Dicranopteris pedata and Gleichenia japonica was confirmed to be (6S,13S)-cleroda-3,14-diene-6,13-diol by an X-ray crystallographic analysis, together with application of the octant rule to the Cotton effect observed in the CD spectrum of its 6-keto derivative. Further investigation of the root-stalks of D. pedata has resulted in the isolated two new glycosides, which were characterised as (6S,13S)-6-O-[beta-D-glucopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl] 13-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-fucopyranosyl] cleroda-3,14-diene and (6S,13S)-6-O-[beta-glucopyranosyl]-13-O-[beta-fucopyranosyl-(1-->2) -alpha-rhamnopyranosyl]-cleroda-3,14-diene. Of these two glycosides, the former glycoside accelerated the growth of the stems of lettuce and inhibited the growth of the roots.

Disaccharides↗
PubMed1997

Effect of the hydroxyl group on the oxidative cleavage (beta-oxidation) of steroidal side chain for bile acid biosynthesis in rat liver homogenate.

Mono-, di-, tri-, and tetrahydroxy-5 beta-cholestan-26-oic acids were incubated with rat liver homogenate (800 x g supernatant and light mitochondrial fraction) to study substrate specificity in the side-chain cleavage reaction (beta-oxidation) of bile acid biosynthesis. The C27-intermediates (5 beta-cholest-24-en-26-oic acids and 24-hydroxy-5 beta-cholestan-26-oic acids) in beta-oxidation and the corresponding C24-bile acids were quantitatively determined by capillary gas chromatography. Monohydroxy-5 beta-cholestan-26-oic acid was not converted into C24-bile acid. Di- and trihydroxy-5 beta-cholestan-26-oic acids were effectively transformed into the C27-intermediates and C24-bile acids. Tetrahydroxy-5 beta-cholestan-26-oic acids were also converted into C27-intermediates and corresponding C24-bile acids. The intermediate 24-hydroxy-5 beta-cholestan-26-oic acids could not be detected in the products by incubation with the light mitochondrial fraction. The total specific activity of protein in the light mitochondrial fraction for the production of C27-intermediates and C24-bile acids was higher than that of 800 x g supernatant solution. The effects of the number and the position of hydroxyl groups on the side-chain degradation are discussed.

Animals↗
PubMed1997

Influence of extracellular H+ and Ca2+ on Ro 22-9194-induced block of sodium current in cardiac myocytes.

1. Ro 22-9194 reduced the Na current in ventricular myocytes in either a tonic block or phasic block manner. 2. Ro 22-9194 had a higher affinity to the inactivated state (Kdi = 10.3 microM) than to the rested state (Kdrest = 180 microM). 3. Extracellular acidification enhanced the tonic block but reduced the phasic block. 4. Elevation of extracellular Ca2+ inhibited the enhancing effects of extracellular acidification. 5. These findings suggest that Ro 22-9194 strongly inhibits Na+ channels of the ventricular myocytes of the diseased hearts, characterized by the depolarized cell membranes and by acid conditions.

Animals↗
PubMed1997

Decreased hepatocyte growth factor level by Wy-14,643, non-genotoxic hepatocarcinogen in F-344 rats.

We examined the role of hepatocyte growth factor (HGF) in the hepatocarcinogenesis caused by [4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio] acetic acid (Wy-14,643), a peroxisome proliferator. Wy-14,643 (100 mg/kg body wt or 0.1% (w/w) in diet) was given orally to male F-344 rats for up to 78 weeks. At 78 weeks the hepatocarcinomas or adenomas in the livers of Wy-14,643-treated rats were observed. Markedly decreased amounts of hepatic HGF mRNA were observed in rats fed Wy-14,643 for 78 weeks. The degree of reduction was higher in the tumour portions of the liver than in the normal portions. After 7 days of treatment with Wy-14,643 (100 mg/kg body wt), the expression of hepatic HGF mRNA was slightly decreased. Wy-14,643 treatment resulted in a time-dependent decrease in hepatic HGF mRNA levels to 63% of the control level after 14 days of treatment. In long-term treatment (18-40 weeks), hepatic HGF mRNA levels were reduced further, reaching 44% of the control level at the 40-week stage. As shown by ELISA, the amounts of hepatic and plasma HGF were significantly decreased by 60 and 50%, respectively, compared with controls. The degree of the reduction correlated with the level of hepatic HGF mRNA. In the lung and kidney, also HGF secretory organs, Wy-14,643 slightly reduced the amount of HGF mRNA. In the colony assay using preneoplastic or neoplastic cells from Wy-14,643-treated livers, 5-15 ng/ml of HGF, which induces proliferation in normal hepatocytes, inhibited the colony formation of neoplastic or preneoplastic cells. The inhibitory effect was dependent on HGF concentration. In the presence of 300 ng/ml HGF, the growth of colonies was suppressed to 36% of the control level. These findings indicate that reductions in hepatic HGF levels, induced by Wy-14,643, may play an important role in the promotion of neoplastic or preneoplastic cell growth.

Animals↗
PubMed1997

Induction of luteinizing hormone surge by pulsatile administration of gonadotropin-releasing hormone analogue in cows with follicular cysts.

LH release in response to pulsatile administration of small amounts of GnRH analogue in cows with follicular cysts was examined. The pulsatile administration of GnRH analogue induced a LH-surge like peak over 10 hr in both normal cows and cows with follicular cysts. The mean peak value of LH in follicular cystic cows did not differ significantly from that of normal cows. All the cows with cysts resumed normal estrous cycles with ovulations within 3 weeks of this treatment. These results suggest that the function of the anterior pituitary for LH release in response to GnRH analogue is not abnormal in cows with follicular cysts, and that cystic cows recover to normal conditions after the pulsatile administration of GnRH analogue.

Animals↗
PubMed1997

Early loss of serum hepatitis C virus RNA can predict a sustained response to interferon therapy in patients with chronic hepatitis C.

OBJECTIVES: We evaluated whether the loss of serum hepatitis C virus (HCV) RNA early in interferon (IFN) therapy would indicate a subsequent response to IFN therapy. METHODS: One hundred fourteen patients with chronic hepatitis C were treated with IFN-alpha for 24 weeks. All patients were positive for anti-HCV antibodies and serum HCV RNA. Serum HCV RNA was measured by highly sensitive and specific RT-PCR (modified Amplicor HCV). RESULTS: Of 114 patients who were treated with IFN-alpha for 24 weeks, 22 of 29 patients (75.9%) who lost HCV RNA at the first week of treatment, 5 of 14 patients (35.7%) who lost HCV RNA at the second week, and 2 of 16 patients (12.5%) who lost HCV RNA at fourth week were judged as sustained responder (SR). The SR rate was significantly higher in patients who lost HCV RNA at the first week of therapy (p < 0.05). On the contrary, none of 55 patients who retained HCV RNA during the first 4 weeks of IFN therapy were judged as SR. Concerning the patients who lost HCV RNA at the first week of therapy, there were no significant differences in the SR rate in either HCV genotype (1b, 2a, and 2b). CONCLUSIONS: Our study confirms that the early response to IFN (loss of HCV RNA at the end of the first week of IFN therapy) can be a predictor of the subsequent sustained response to IFN therapy. Additionally, positivity of HCV RNA at the fourth week of IFN therapy can be a predictor of the subsequent nonsustained response to IFN therapy.

Adolescent↗
PubMed1997

Effect of the side-chain structure on the specificity of beta-oxidation in bile acid biosynthesis in rat liver homogenates.

3Alpha, 7alpha, 12alpha-trihydroxy-5beta-cholestan-26-oic acid (C27-5beta-cholestanoic acid) derivatives with different carbon-number side chains were incubated with rat liver 800 g supernatant to study the effect of the side-chain length on the beta-oxidation system in bile acid biosynthesis. The intermediate alpha, beta-unsaturated and beta-hydroxylated bile acids, and the corresponding degradation products, were quantitatively determined by gas chromatography. The longer side-chained derivatives (C28- and C29-5beta-cholestanoic acids) were converted into corresponding sidechain degradation products, and the alpha,beta-unsaturated and beta-hydroxylated intermediates were also produced. On the other hand, the shorter side-chained derivative (C26-5beta-cholestanoic acid) only gave alpha,beta-unsaturated intermediate. The total formation of intermediates and degradation products from corresponding substrates was in the order of C27- > C28- > C29- > C26-5beta-cholestanoic acids. In the case of clofibrate-treated rat liver 800 g supernatant, the formation of intermediates and final degradation products from C28- and C29-5beta-cholestanoic acids increased significantly. These longer side-chained analogues seemed to be subjected to beta-oxidation system(s) induced with clofibrate treatment. The effect of a terminal methyl group in the side chain of 5beta-cholestanoic acid on the oxidation system was also investigated using 3alpha, 7alpha, 12alpha-trihydroxy-27-nor-5beta-cholestanoic acid derivatives as enzymatic substrates. These derivatives gave corresponding side chain degradation products, but the formation of intermediates was not detected. The formation of side chain cleavage products from 27-nor-5beta-cholestanoic acid derivatives increased to 10 to 25-fold that of the controls by treatment with clofibrate. The results suggested that the beta-oxidation system for 27-nor-5beta-cholestanoic acid derivatives was different from that for C27-5beta-cholestanoic acid, despite their bile acid steroidal structure.

Animals↗
PubMed1997

[A case of Sairei-to-induced pneumonitis diagnosed by lymphocyte stimulation test of bronchoalveolar lavage fluid].

A 51-year-old woman was admitted with fever, cough and dyspnea. She had been taking Sairei-to, a traditional Chinese medicine, for 2 months. On admission, chest X-ray revealed a ground-glass appearance in the lung fields bilaterally and serum LDH was elevated. A differential cell count of the bronchoalveolar lavage fluid (BALF) showed that lymphocytes were increased, with a decreased ratio of CD4/CD8 cells. A lymphocyte stimulation test (LST) for Sairei-to using the lymphocytes in BALF was a positive, although a test of peripheral blood was negative. Sairei-to-induced pneumonitis was diagnosed based on the clinical course, laboratory findings, BALF cell analysis and LST of BALF. Only 4 cases of pneumonitis due to Sairei-to have been reported. This case suggests that LST of BALF is useful for diagnosing drug-induced pneumonitis.

Bronchoalveolar Lavage Fluid↗