Biomedical subjects

Y Inui

Publications and source records attributed to Y Inui.

At least 19 recordsLinked to original sources

PubMed2001

Effect of pravastatin on survival in patients with advanced hepatocellular carcinoma. A randomized controlled trial.

Chemotherapy is not effective for hepatocellular carcinoma (HCC). HMG-CoA redutase inhibitors have cytostatic activity for cancer cells, but their clinical usefulness is unknown. To investigate whether pravastatin, a potent HMG-CoA reductase inhibitor, prolongs survival in patients with advanced HCC, this randomized controlled trial was conducted between February 1990 and February 1998 at Osaka University Hospital. 91 consecutive patients <71 years old (mean age 62) with unresectable HCC were enroled in this study. 8 patients were withdrawn because of progressive liver dysfunction; 83 patients were randomized to standard treatment with or without pravastatin. All patients underwent transcatheter arterial embolization (TAE) followed by oral 5-FU 200 mg(-1)d for 2 months. Patients were then randomly assigned to control (n = 42) and pravastatin (n = 41) groups. Pravastatin was administered at a daily dose of 40 mg. The effect of pravastatin on tumour growth was assessed by ultrasonography. Primary endpoint was death due to progression of HCC. The duration of pravastatin administration was 16.5 +/- 9.8 months (mean +/- SD). No patients in either group were lost to follow-up. Median survival was 18 months in the pravastatin group versus 9 months in controls (P = 0.006). The Cox proportional hazards model showed that pravastatin was a significant factor contributing to survival. Pravastatin prolonged the survival of patients with advanced HCC, suggesting its value for adjuvant treatment.

Adult↗

PubMed2000

An adipocyte-derived plasma protein, adiponectin, adheres to injured vascular walls.

Adipose tissue secretes a variety of proteins into the bloodstream. We have previously reported a novel cDNA, apM1 (adipose most abundant gene transcript 1), which is specifically and abundantly expressed in adipose tissue [1]. Primary structure analysis predicted that the apM1 gene product possesses significant homology to collagens VIII, X and complement factor C1q, and we named it adiponectin. In the current study, we analyzed characteristics of adiponectin in vitro and in vivo. Adiponectin protein was proved to be secreted into the medium when the cDNA was transfected to COS cells. Anti-adiponectin cross-reactivities were abundantly detected in the human plasma. In solid-phase binding assays, adiponectin specifically bound to collagen types I, III and V, which are present in vascular intima. Immunohistochemical analysis revealed that adiponectin was detected in the walls of the catheter-injured vessels but not in the intact vascular walls. These data suggest that adiponectin is a plasma protein produced by adipose tissue and accumulates in vascular walls when the endothelial barrier is injured.

Adipocytes↗

PubMed1999

Comparative studies of modulatory effect to the function of rat peritoneal neutrophils treated with new quinolones.

Some of the immunological effects of a variety of new quinolones on adhesion, phagocytosis, and production of reactive oxygen intermediators in neutrophils were studied. Ofloxacin, lomefloxacin, fleroxacin, and levofloxacin potentiated the phagocytosis of Escherichia coli in neutrophils. Moreover, lomefloxacin, and sparfloxacin significantly potentiated adhesion of neutrophils. In contrast, tosufloxacin was effective in significantly and persistently potentiating the production of superoxide anion, whereas the other agents markedly inhibited such production. Furthermore, tosufloxacin was effective in significantly potentiating the production of hydrogen peroxide, whereas sparfloxacin markedly inhibited such production. These results suggest that the new quinolones at a therapeutic concentration may affect functions such as phagocytosis, and production of superoxide anion in neutrophils.

4-Quinolones↗

PubMed1999

Augmented growth response to IGF-1 via increased IRS-1 in Chinese hamster ovary cells expressing kinase-negative insulin receptors.

AIMS/HYPOTHESIS: Although both increased cell growth and impaired insulin signalling have been associated with diabetes, this association has not been investigated. Insulin-like growth factor-1 (IGF-1), a structural and functional analog of insulin, may play a part in the aberrant insulin receptor-mediated signalling observed in diabetes. METHODS: To investigate the consequence of this impaired signalling on cell proliferation and transformation, we transfected Chinese hamster ovary cells with cDNA encoding a kinase-defective insulin receptor. RESULTS: In these mutant cells, the mitogenic and metabolic effects of insulin were reduced compared with control cells (p < 0.05) and this was due to a dominant negative effect. In contrast, these mutant cells showed a higher mitogenic response to IGF-1 than control cells, although IGF-1 receptor expression was similar in both cell lines. There was no statistically significant difference in mitogenic response, however, to platelet-derived growth factor, basic fibroblast growth factor and heparin-binding epidermal growth factor-like growth factor. Variables of the IGF-1 signalling pathway, including tyrosine phosphorylation of insulin receptor substrate-1 and activation of mitogen-activated protein kinase and phosphatidyl inositol 3 kinase, were also augmented in mutant cells. Insulin receptor substrate-1 message and protein abundance were higher in mutant than in control cells. Moreover, mutant cells had a higher mitogenic potential in low-serum-containing medium, suggesting that these cells have a transformed phenotype. CONCLUSION/INTERPRETATION: These findings suggest that an impaired insulin signalling may upregulate insulin receptor substrate-1 and that this, in turn, leads to increased IGF-1 signalling, a phenomenon that is possibly associated with increased cell growth in diabetes.

Adaptor Proteins, Signal Transducing↗

PubMed1999

Cloning and expression of yellowtail ascites virus segment A.

cDNA of yellowtail ascites virus (YAV) segment A encoding a polyprotein of VP2, NS, and VP3 has been cloned. Comparison of the nucleotide and the deduced amino acid sequences showed very high homology between YAV and other aquatic birnaviruses. The two small open reading frames (VP5) besides the 5' terminus of the VP2 gene were found on segment A of YAV. Proteins encoded by cDNAs from segment A and the serotype-specific epitope region on VP2 were expressed using a baculovirus vector. Western blot analysis confirmed that a polyprotein was expressed and processed into VP2 and VP3 in insect cells infected with the recombinant baculovirus containing the complete polyprotein coding region. In the case of expression in silkworm larvae, only VP3 was detected in hemocytes and fat body of silkworm larvae infected with the recombinant virus. The recombinant fusion protein consisting of VP2 epitope region and polyhedrin was expressed in insect cells and cross-reacted with a mouse monoclonal antibody against VP2 which had a neutralizing activity to YAV.

Amino Acid Sequence↗

PubMed1998

Transforming growth factor-beta1-induced degradation of activated Src tyrosine kinase in rat fibroblasts.

Transforming growth factors-beta (TGF-betas) play pivotal roles in the regulation of cell growth and differentiation, although little is known regarding the regulation of cytoplasmic components by TGF-betas. Src tyrosine kinase is required for signal transduction of various cytokine receptors, including epidermal growth factor (EGF), platelet-derived growth factor (PDGF), and G-protein coupled receptors. Moreover, Src tyrosine kinase is important in signal cross-talk between these receptors. To determine whether Src kinase is also involved in TGF-beta signaling, we examined the effects of TGF-beta1 on Src in the rat fibroblast cell line 3Y1 and in v-Src-transformed 3Y0 (SR-3Y1). TGF-beta1 inhibited mitogen-activated protein kinase activity and inhibited growth in SR-3Y1 cells, while it did not affect the growth of 3Y1 cells. TGF-beta1 significantly decreased v-Src kinase activity and protein abundance in SR-3Y1 cells, mainly by accelerating the degradation of v-Src. In contrast, in 3Y1 cells, TGF-beta1 did not affect c-Src abundance or kinase activity. However, upon activation of c-Src in 3Y1 cells by PDGF, TGF-beta1 decreased Src abundance. Additionally, in 3Y1 cells transfected with an activated c-Src mutant which lacks the SH3 domain, its level was decreased by TGF-beta1 treatment. These findings suggest that TGF-beta1 specifically induces degradation of activated Src kinase. This may be a novel mechanism for cross-talk between growth factors and TGF-beta1.

Animals↗

PubMed1998

Altered regulation of Src tyrosine kinase by transforming growth factor beta1 in a human hepatoma cell line.

Transforming growth factor betas (TGF-betas) are the potent growth inhibitors for various cell types. Certain transformed cells, however, show poor response to TGF-beta-induced growth inhibition, which contributes to their uncontrolled proliferation. Recently, we have reported that TGF-beta1 induces degradation of activated Src tyrosine kinase in rat fibroblasts. To elucidate the alteration in TGF-beta signaling pathway in tumor cells that cannot respond to the cytokine, we compared the effects of TGF-beta1 on Src kinase in two human hepatoma cell lines, TGF-beta1-insensitive Mahlavu cells and TGF-beta1-sensitive HepG2 cells. TGF-beta1 decreased Src kinase activity in HepG2 cells, but increased cellular Src levels and Src kinase activity in Mahlavu cells. Co-incubation of Mahlavu cells with TGF-beta1 and 12-O-tetradecanoyl phorbol 13-acetate (TPA) decreased Src protein levels and Src kinase activity, inducing TGF-beta1 sensitivity. TGF-beta1 induced tyrosine dephosphorylation of Ras guanosine triphosphatase-activating protein (Ras-GAP) and Ras inactivation in HepG2 cells, but induced Ras-GAP phosphorylation and Ras activation in Mahlavu cells. The Src kinase inhibitor abolished the increase of Src kinase activity in TGF-beta1-treated Mahlavu cells, and induced TGF-beta1 sensitivity. These findings suggest that regulation of Src kinase by TGF-beta1 is altered in Mahlavu cells. The altered regulation of Src may contribute to TGF-beta1 insensitivity in this cell line, at least in part through activation of Ras.

Animals↗

PubMed1998

Effects of glycosylation of the residue at position 14 in ovine angiotensinogen on the human renin reaction.

A mutant angiotensinogen, S14N, in which Ser14 of ovine angiotensinogen was replaced by Asn to form a N-glycosylation site, was produced in CHO cells. The molecular weight was about 3,000 larger than that of wild-type ovine angiotensinogen, indicating that S14N angiotensinogen was glycosylated at Asn14. In the reaction with human renin, the km of mutant angiotensinogen was 3 times increased, but the Vmax was not affected by the mutation.

Amino Acid Sequence↗

PubMed1998

Effects of substitution of Val for Leu11 of ovine angiotensinogen on renin activity.

A mutant angiotensinogen, L11V, in which Val11 was substituted for Leu11 of ovine angiotensinogen was prepared to have the same scissile peptide bond as the human one. The mutation didn't vary Km and kcat of human renin for the ovine substrate, but decreased those of rat renin to one half and one fortieth, respectively. Distances between the P1' subsite of angiotensinogens and the 224th (human renin numbering) residue in the S1' subsite of renins were estimated by molecular modelings. The marked decrease in kcat of rat renin for L11V could be attributed to the elongated distance between Val11 of L11V and Val221 of rat renin. It was also suggested that the distance is the reason why the human substrate cannot be cleaved by heterologous renins.

Amino Acid Sequence↗

PubMed1997

Molecular cloning and sequence analysis of the cDNA for the mouse counterpart to adult hamster liver purified growth inhibitory factor.

A cDNA clone encoding the mouse counterpart to adult hamster liver purified growth inhibitory factor (PGIF) was isolated from a mouse liver cDNA library by using antibodies raised against PGIF and sequenced. It contained a single open reading frame with a coding capacity for a 323 amino acid protein. Sequence analysis showed that it shared high homology with rat- and human liver arginases: the cDNA clone was 92% identical for rat arginase at the nucleotide level and was 93% identical to it at the deduced amino acid level. These results suggest that PGIF derived from adult hamster liver was identical or closely related to an isoform of hamster liver arginases.

Amino Acid Sequence↗

PubMed1997

Efficacy of combination therapy of interferon-alpha with ursodeoxycholic acid in chronic hepatitis C: a randomized controlled clinical trial.

The efficacy of interferon-alpha therapy in the treatment of chronic hepatitis C is still limited. A combination therapy of interferon-alpha with ursodeoxycholic acid (UDCA) was tested for its efficacy in the treatment of chronic hepatitis C by a randomized controlled study. Eighty consecutive Japanese patients with chronic hepatitis C were randomly divided into two groups: one group was treated with interferon-alpha (group A, n = 40) and the other with a combination of interferon-alpha and UDCA (group B, n = 40). In both groups, human interferon-alpha (6 million units per day) was intramuscularly injected daily for 2 weeks and then three times a week for 22 weeks: this 24-week period was followed by 24 weeks of observation. In group B, UDCA was also administered, daily at a dose of 600 mg orally, from the beginning of the interferon therapy and administration was continued for 48 weeks. The rates for ALT normalization and clearance of hepatitis C virus (HCV) viremia at the end of the 24-week interferon therapy were similar for groups A and B (58% vs 60% and 55% vs 48%, respectively). At the end of the 24-week follow-up, the sustained normalization rates for ALT levels for the two groups were not different (35% vs 43%), while the rate of clearance was higher in group B (40%) than in group A (23%), but the difference was not significant (P = 0.14). The sustained complete response, i.e., HCV RNA negativity at the end of the follow-up, as well as the maintenance of ALT normalization during the follow-up period, was more frequent in group B (38%) than in group A (18%) although the difference was not significant (P = 0.08). The rate of HCV reactivation after interferon was discontinued was significantly lower in group B (16%) than in group A (59%) (P < 0.01). Although this combination therapy did not lead to a sufficiently sustained complete response, it could serve as adjuvant antiviral therapy when a suitable dosage and administration period are determined.

Administration, Oral↗

PubMed1997

Manumycin and gliotoxin derivative KT7595 block Ras farnesylation and cell growth but do not disturb lamin farnesylation and localization in human tumour cells.

Recently, many inhibitors of farnesyl protein transferase (FPTase) have been identified. Some of them interrupt cell growth in addition to Ras and nuclear lamin processing of Ras-transformed cells. We have tested the effect of the FPTase inhibitors manumycin, an analogue of farnesyl diphosphate, and KT7595, a gliotoxin derivative, on Ras farnesylation, DNA synthesis and the anchorage-dependent and -independent growth of human colon carcinoma (LoVo), hepatoma (Mahlavu and PLC/PRF/5) and gastric carcinoma (KATO III). Both drugs severely inhibited DNA synthesis, cellular proliferation and Ras farnesylation in LoVo and moderately reduced them in Mahlavu and PLC/PRF/5 but not in KATO III. Complete sequencing of ras genes, however, revealed that LoVo and KATO III have activated Ki-ras and activated N-ras, respectively, whereas Mahlavu and PLC/PRF/5 have no activated ras. We next checked whether the inhibition of the cellular proliferation is due to the blocking of nuclear lamin function. Neither drug disturbed lamin farnesylation and localization, as demonstrated using metabolic labelling, immunoblotting and indirect immunofluorescence. These results indicate that manumycin and KT7595 can inhibit Ras farnesylation and cell growth without disturbing the farnesylation and localization of the lamins on human tumour cell lines.

Alkyl and Aryl Transferases↗

PubMed1997

Modulation of apolipoprotein gene expression in fatty liver of obese rats: enhanced APOA-IV, but no APOB expression by a high sucrose diet.

OBJECTIVE: Hepatic lipoprotein production is important to the understanding of mechanisms involved in the development of fatty liver and hyperlipidemia. Previously, we have reported that hepatic fatty acid synthesis and apolipoproteinB transcription are increased in obese rats. Here, we describe the effects of a high sucrose diet on hepatic fatty acid synthesis and apolipoprotein gene expression in obese rats. DESIGN: Obese rats with ventromedial hypothalamic lesions were fed on a high sucrose diet (30.3% of cal) or lab chow for 11 weeks. RESULTS: Serum triglycerides and plasma immuno-reactive insulin concentrations were further increased in the obese rats fed a high sucrose diet. The experimental diet increased the activity of hepatic acetyl-CoA carboxylase, the rate limiting enzyme for hepatic fatty acid synthesis, and triglycerides content, concurrent with an increase abundance of apolipoproteinA-IC mRNA in the obese rats. Despite further accumulation of hepatic triglycerides there was no further increase in hepatic apolipoproteinB mRNA abundance in the obese rats fed the high sucrose diet. CONCLUSION: These data suggest that the synthesis of hepatic fatty acids but not of apolipoproteinB is further increased in obese rats fed the high sucrose diet, and that apolipoproteinA-IV gene expression may be modulated in response to alterations in hepatic triglycerides flux.

Acetyl-CoA Carboxylase↗

PubMed1997

Characterization of a 34 kDa immunoreactive peptide with the anti protein kinase C antibody which can recognize part of the C4 region.

Among the immunoreactive peptides from hamster tissues with the antibody (Ab-1) which can recognize part of the C4 conserved region of protein kinase C (PKC), a peptide with 34 kDa (34 kDa species) is constitutively detected in the soluble and the nuclear but not in the particulate fractions. The partially purified 34 kDa species demonstrates no phospholipid-dependent or independent PKC activity and no phorbol 12,13 dibutyrate (PDBu) binding, and is not phosphorylated under the assay condition of PKC activity. The species inhibits the enzymic activity of the partially purified PKC from hamster brain in an uncompetitive manner with Ki of 200 +/- 23 nM.

Animals↗

PubMed1997

High concentration of glucose increases mitogenic responsiveness to heparin-binding epidermal growth factor-like growth factor in rat vascular smooth muscle cells.

The effect of a high extracellular glucose concentration on the mitogenic response of rat vascular smooth muscle cells (SMCs) to heparin-binding epidermal growth factor-like growth factor (HB-EGF) was investigated. The mitogenic effect of HB-EGF was significantly greater in SMCs cultured in high glucose (25 mmol/L) than in cells cultured in low glucose (5.5 mmol/L) or at high osmolarity (5.5 mmol/L glucose plus 19.5 mmol/L mannitol). The mitogenic effect of epidermal growth factor (EGF), which shares the EGF receptor with HB-EGF, was not affected by glucose concentration. The mitogenic effect of HB-EGF was greater when incubated with heparan sulfate (HS) isolated from SMCs cultured in high glucose than with HS from cells cultured in low glucose. HS synthesized by cells in high glucose was of smaller molecular size and less sulfated than HS synthesized by cells in low glucose. The abundance of mRNA encoding HS-N-deacetylase/N-sulfotransferase (HS-NdAc/NST), a regulatory enzyme in the biosynthesis of HS, was decreased by high glucose in a protein kinase C-independent manner. These observations suggest that the enhanced mitogenic response to HB-EGF in SMCs cultured in high glucose may be attributable to changes in cell-associated HS. Downregulation of HS-NdAc/NST gene expression by high glucose may be related to the altered HS biosynthesis.

Animals↗

PubMed1997

Cholecystoparesis with diabetic autonomic neuropathy.

A 69-year-old male diabetic patient was hospitalized with pneumonia in February 1996. Abdominal ultrasonography performed as a routine examination on admission revealed marked dilatation of gallbladder with a fasting maximal size of 25.7 cm2 compared with 8.8 +/- 2.9 cm2 evaluated in 30 male healthy controls aged 67 +/- 8 years old. Four months after recovery from pneumonia, abnormal gallbladder dilatation remained unchanged (25.0 cm2), while dilatation had not been observed on an examination performed 6 years earlier (9.8 cm2). Because of accompanying neurological defects, we suppose that cholecystoparesis may be caused by progression of autonomic neuropathy in this patient with diabetes mellitus.

Aged↗

PubMed1996

Inhibition of cell growth of human hepatoma cell line (Hep G2) by a farnesyl protein transferase inhibitor: a preferential suppression of ras farnesylation.

So far, treatment with anti-cancer agents has failed to achieve satisfactory results in hepatocellular carcinoma. In the process of hepatocarcinogenesis, ras has been shown to play a role. ras requires a farnesyl moiety for activation. It has been found that UCFI-C (manumycin), an antibiotic, inhibits farnesyl protein transferase, an enzyme that catalyzes farnesylation. Therefore, we investigated the effects of UCFI-C on cell growth, prenylation of cellular proteins including ras and Rapl, MAP kinase activity, activities of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, and synthesis of cholesterol in a ras-activated human hepatoma cell line, Hep G2. Treatment with varying concentrations of UCF1-C(10-30 microM for 24 and 72 hr resulted in a time- and dose-dependent inhibition of cell numbers. 3H-Thymidine incorporation was also inhibited in a dose-dependent manner, with 50% inhibition after 44 hr being observed at a concentration of 17 microM. UCFI-C dose-dependently inhibited ras farnesylation and MAP kinase activity, but did not decrease Rap 1++ geranylgeranylation or prenylation of 21-to 26-kDa proteins. Neither the activities of 3-hydroxy-3-methylglutaryl-coenzyme A reductase nor cholesterol synthesis were inhibited. These results suggest that UCFI-C antagonizes the growth of Hep G2 via the suppression of ras farnesylation and could be a lead for the development of new anti-cancer agents blocking the function of oncogenic ras associated with human cancer, including hepatocellular carcinoma.

Alkyl and Aryl Transferases↗

PubMed1996

Distribution and subcellular localization of a growth inhibitory factor in hamster liver and its intracellular partner(s).

The subcellular, intralobular distributions and intracellular partner(s) of a factor which inhibits the proliferation of cell growth (Hashimoto C. et al. (1994) Biochim. Biophys. Acta 1221, 107-117) were determined in hamster livers, using a combination of immunological and biochemical techniques. The IgG fraction from an antiserum raised against the growth inhibitory factor with 37 kDa was shown to be highly specific for the antigen. The nuclear and cytosolic fractions demonstrated inhibitory effects on cell growth and Western blot analysis revealed that both fractions contained the immunoreactive 37 kDa protein with the anti-inhibitory factor IgG but microsomal and mitochondrial fractions did not. The nuclear and cytoplasmic localization of the inhibitory factor were further confirmed by immunochemical staining mediated through the immune IgG and an avidin-biotinylated horseradish peroxidase complex, the parenchymal liver cells were clearly stained, but endothelial and connective tissue cells were not. Although some staining was evident throughout the liver parenchyma, the hepatocytes with most intensively stained nuclei were located in the periportal region. In the liver from hamsters 6 days old or the regenerating hamster livers 3 days after partial hepatectomy, the staining intensity was low and the number of hepatocytes with the inhibitory factor positive nuclei was very few compared with the adult hamster livers. In primary cultures of the isolated hepatocytes from adult hamster the inhibitory factor disappeared from nuclei after incubation for 24-48 h. The extracts of hepatic nuclei from adult hamsters were immunoprecipitated with either the anti-growth inhibitory factor IgG or a monoclonal antibody to the RM protein. The growth inhibitory factor and the RB protein coprecipitated in each case, implying that the proteins were complexed with each other in the nuclei. The RB protein family is composed of two sets of species, an un- or underphosphorylated species and a hyperphosphorylated one. It was suggested that the factor bound preferentially to the un- or underphosphorylated member of the family.

Animals↗