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Biomedical subjects

R Hirai

Publications and source records attributed to R Hirai.

At least 37 records · Page 2Linked to original sources
PubMed1992

Transforming growth factor beta 1-specific binding proteins on human vascular endothelial cells.

Transforming growth factor beta (TGF beta) regulates the growth of human umbilical vein endothelial cells (HUVEC) differently depending on the isoform of TGF beta and the culture conditions. The cells are resistant to growth inhibition by TGF beta when the cells are cultured on substratum coated with gelatin. However, the proliferation of HUVEC cultured on substratum without a gelatin coating is inhibited by TGF beta, depending on the isoform and concentration of TGF beta. Binding assays with 125I-TGF beta 1 reveal that HUVEC contain a single class of high-affinity (Kd = 4.4 pM) TGF beta 1 binding sites with 8500 sites per cell. Affinity cross-linking studies demonstrate that HUVEC express 180 and 80 kDa TGF beta 1 binding sites that do not bind TGF beta 2. The reduction and the removal of glycosaminoglycans does not affect the electrophoretic mobility of the 180-kDa binding protein cross-linked with 125I-TGF beta 1. Therefore, the 180-kDa TGF beta 1 binding protein is not related to the type III TGF beta receptor, but might be a novel TGF beta 1-specific receptor/binding protein expressed on vascular endothelial cells. The expression of TGF beta 1 binding sites is not affected by the presence or absence of the gelatin coating on the culture substratum. The data suggest that a gelatin coating does not regulate the susceptibility of HUVEC to TGF beta 1 at the level of the receptor/binding proteins, and that growth inhibition of HUVEC by TGF beta 1 is linked to the regulation of extracellular matrices required for the interaction between the cells and the substratum.

Binding Sites↗
PubMed1991

Sigmoid colon obstruction due to blunt abdominal trauma: a case report.

Post-traumatic colonic stenosis (obstruction) is rare. We experienced a case of sigmoid obstruction due to blunt abdominal trauma. A 75-year-old man was hit on the lower abdomen 3 days before admission and gradually developed abdominal pain and distension. Laboratory data showed severe inflammation and a barium enema disclosed obstruction of the sigmoid colon. Conservative treatment was carefully carried out, because there was no sign of peritoneal irritation and there were passages of normal stool and flatus. The sigmoid obstruction gradually improved and the stenosis was almost undetectable on a barium enema on the 51st hospital day. An abdominal contusion is the most likely causal factor in this case. Compression of the sigmoid colon between the abdominal wall and the promontory of the pelvis is the most possible explanation.

Abdominal Injuries↗
PubMed1990

Epidermal growth factor (EGF)-nonresponsive variants of normal rat kidney cell line: response to EGF and transforming growth factor-beta.

Anchorage-independent growth in soft agar of normal rat kidney (NRK) fibroblasts depends on both transforming growth factor-beta (TGF-beta) and epidermal growth factor (EGF) (or TGF-alpha). We have isolated two EGF-nonresponsive cell lines, N-3 and N-9, from chemically mutagenized NRK cells, after selection of mitogen-specific nonproliferative variants in the presence of EGF and colchicine. Saturation binding kinetics with 125I-EGF showed one-half or fewer EGF receptors in N-3 and N-9 than in their parental NRK. Cellular uptake of 2-deoxy-D-glucose was enhanced in all NRK, N-3, and N-9 cell lines by TGF-beta treatment, whereas treatment with EGF significantly enhanced the cellular uptake of the glucose analog in NRK cells, but not in N-3 and N-9 cells. DNA synthesis of NRK during the quiescent state, but not that of N-3 and N-9, was stimulated by EGF. Anchorage-independent growth of N-9 could not be observed even in the presence of both EGF and TGF-beta, whereas that of N-3 was significantly enhanced by TGF-beta alone. EGF stimulated phosphorylation of a membrane protein with molecular size 170 kDa of NRK, but not of N-3, when immunoprecipitates reacting with anti-phosphotyrosine antibody were analyzed. Exposure of NRK cells to EGF increased cellular levels of TGF-beta mRNA, but there appeared little expression of TGF-beta mRNA in N-3 and N-9 cells. Exposure of N-3 cells to EGF or TGF-beta enhanced the secretion of EGF into culture medium, but exposure of NRK or N-9 cells did not. Altered response to EGF of N-3 or N-9 might be related to their aberrant growth behaviors.

Animals↗
PubMed1989

Comparison of the regional distribution of calspectin (nonerythroid spectrin or fodrin), alpha-actinin, vinculin nonerythroid protein 4.1, and calpactin in normal and avian sarcoma virus- or Rous sarcoma virus-induced transformed cells.

With fluorescence and interference reflection microscopy (IRM), we compared the regional distribution of calspectin, its interacting proteins (nonerythroid protein 4.1 and calpactin), alpha-actinin, and vinculin in NRK cells and their avian sarcoma virus (ASV)- or temperature-sensitive (ts) Rous sarcoma virus (RSV)-transformed cells. The localization of these cytoskeletal proteins was determined with the specific antibodies. In NRK cells, alpha-actinin and vinculin were concentrated at adhesion plaques. By contrast, calspectin was distributed throughout the cytoplasm, but not concentrated at adhesion plaques. In ASV- and ts RSV-transformed cells, all three cytoskeletal proteins were concentrated at dot structures representing cellular feet. Nonerythroid protein 4.1 and calpactin were diffusely distributed throughout the cytoplasm of NRK cells and their transformed counterparts. In the case of calpactin, a part of this protein was excluded near regions of the terminal ends of stress fibers. These two proteins did not show the restricted location at the dot structures of transformed cells. From these findings, it is apparent that the accumulation of calspectin into dot structures is a specific event for cell transformation induced by the src protein.

Actinin↗
PubMed1988

Effect of transforming growth factor beta on cell proliferation and glycosaminoglycan synthesis by rabbit growth-plate chondrocytes in culture.

The effects of the transforming growth factor beta (TGF-beta) on the growth and glycosaminoglycan synthesis of rabbit growth plate-chondrocytes in culture were studied. In serum-free medium, TGF-beta caused dose-dependent inhibition of DNA synthesis by chondrocytes, measured as [3H]thymidine incorporation (ED50 = 0.1-0.3 ng/ml). The inhibitory effect was maximal at a dose of 1 ng/ml, and extended for a duration of 16-42 h. In contrast, TGF-beta potentiated the synthesis of DNA stimulated by fetal calf serum (FCS). Addition of TGF-beta (1 ng/ml) to cultures containing 10% FCS increased [3H]thymidine incorporation to 1.6-times that in cultures with 10% FCS alone. Consistent with this finding, TGF-beta potentiated DNA synthesis stimulated by the purified growth factors such as platelet-derived growth factor (PDGF), epidermal growth factor (EGF) and fibroblast growth factor (FGF). The maximal stimulation of DNA synthesis by FGF (0.4 ng/ml) was further potentiated dose dependently by TGF-beta (ED50 = 0.1 ng/ml, maximum at 1 ng/ml). When the cultures were treated with the optimal concentrations of TGF-beta (1 ng/ml) and FGF (0.4 ng/ml), [3H]thymidine incorporation was 3-times higher than that of cultures treated with FGF alone. This TGF-beta-induced potentiation of DNA synthesis was associated with replication of chondrocytes, as shown by a marked increase in the amount of DNA during treatment of sparse cultures of the cells with the growth factors for 5 days. In contrast, TGF-beta caused dose-dependent stimulation of glycosaminoglycan synthesis in confluent cultures of growth-plate chondrocytes (ED50 = 0.3 ng/ml, maximum at 1 ng/ml). This stimulatory effect of TGF-beta was greater than that of insulin-like growth factor I (IGF-I) or PDGF. Furthermore, TGF-beta stimulated glycosaminoglycan synthesis additively with IGF-I or PDGF. Recently, it has been suggested that bone and articular cartilage are rich sources of TGF-beta, whereas epiphyseal growth cartilage is not. Thus, the present data indicate that TGF-beta may be important in bone formation by modulating growth and phenotypic expression of chondrocytes in the growth plate, possibly via a paracrine mechanism.

Animals↗
PubMed1988

Tyrosine protein kinase in preneoplastic and neoplastic rat liver.

When rats are subjected to chemical hepatocarcinogenesis according to the protocol of D. Solt and E. Farber ((1976) Nature (London) 263, 701-703), the liver exhibits elevated levels of tyrosine protein kinase activity as early as 3 weeks after the injection of diethylnitrosoamine. A more striking elevation in tyrosine protein kinase activity is noted in rat hepatomas induced by administration of chemical carcinogens, in particular that of 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB). Tyrosine protein kinase solubilized from the particulate fraction of 3'-Me-DAB-induced hepatoma has a molecular weight identical to that of p60v-src, cross-reacts with p60v-src immunologically, phosphorylates the heavy chain of anti-p60v-src IgG, and probably belongs to a family of p60c-src. The tyrosine protein kinase from the particulate fraction of normal rat liver is indistinguishable from the hepatoma kinase in these properties; thus it apparently differs only in the level of activity. Whether the liver and hepatoma kinases differ merely quantitatively or whether they differ even qualitatively, however, remains to be elucidated.

Affinity Labels↗
PubMed1987

[Adenocarcinoma of an extraperitoneal rectum in a 17-year-old female].

A 17-year-old female with an adenocarcinoma of the extraperitoneal rectum, which was diagnosed correctly by preoperative intrarectal ultrasonography as being in Dukes' A stage, was operated on, this surgery performed adhering to function preserving procedures. Histologically, the tumor uncovered was found to be a well differentiated adenocarcinoma and, as had been expected, in Dukes' A stage. An absolute curative operation was achieved. The operative procedure for juvenile rectal cancer must be planned to achieve both tumor removal and bodily function preservation to assure the best possible quality of postoperative life. We recommend intrarectal ultrasonography at the preoperative stage, the results to be used in deciding on the operative procedure.

Adenocarcinoma↗
PubMed1986

Phosphorylated 350 kD protein in the nucleus as it is associated with cell transformation.

Protein kinases are thought to play a key role in signal transduction and oncogenesis, but little is known about the intranuclear phosphorylation events associated with transformation. Here we report on cell cycle-dependent phosphorylation of cytoskeleton-associated 350 kD protein and the regular interchange in its location between the nucleus and cytoplasm of normal cells. Persistent intranuclear location of the phosphorylated 350 kD protein was also found throughout the cell cycle in transformed cells, as detected by immunoprecipitation of 32P-phosphorylated 350 kD protein from isolated nuclei and immunofluorescent staining with a monoclonal antibody that recognized phosphorylated site of 350 kD protein. A conditional transformed phenotype induced by a temperature-sensitive (ts) viral oncogene or a transforming growth factor was also associated with the intranuclear presence of the phosphorylated 350 kD protein. Thus the 350 kD protein seems to be a target molecule of protein kinases that are stimulated directly or indirectly by growth factors or by oncogene products in the nucleus, and appears to be a new transformation-related nuclear antigen.

Animals↗
PubMed1986

Separation of sarcoma growth inhibitor from avian sarcoma virus-transformed rat cells.

A cell growth inhibitor was isolated from an avian sarcoma virus-transformed rat cell line (77N1), from which we had previously obtained a novel transforming growth factor, TGF gamma 2. The growth inhibitor (named SGI) was found in cell extract of 77N1 cells and was separable from TGF gamma 2 by means of ion exchange chromatography. SGI inhibited the DNA synthesis of serum-starved, TGF gamma 2-stimulated BALB3T3 cells as well as the spontaneous and TGF-induced colony formation of various cells in semisolid agar. We present evidence that SGI is distinct from the ubiquitous growth modulator TGF beta, and we discuss the possible role of SGI in the neoplastic cell proliferation.

Animals↗
PubMed1986

Characterization of intra- and extracellular transforming growth factors from normal and avian sarcoma virus-transformed rat cells.

Intra- and extracellular transforming growth factors (TGFs) have been characterized in an avian sarcoma virus-transformed rat cell line, 77N1, and the nontransformed parental cell line, NRK. Serum-free conditioned medium from 77N1 and cell extracts from NRK and 77N1 were subjected to ion exchange column chromatography. Intracellular TGFs in cell extracts of NRK and 77N1 cells showed a major peak of DNA synthesis-stimulating and colony-forming activities which eluted in the 0.10 to 0.15 M salt concentration region. Extracellular TGF in conditioned medium of 77N1 cells showed a major peak of activity which eluted at 0.05 to 0.06 M salt concentration. Furthermore partially purified extracellular TGF had a molecular weight of about 40,000 daltons, whereas that for intracellular TGF was about 12,000 daltons. These intra- and extracellular TGFs, as well as TGF gamma 2 which was purified from 77N1 cell extract, were heat- and acid-labile polypeptides sensitive to treatment with dithiothreitol. Radioimmunoprecipitation analyses with antiserum against TGF gamma 2 demonstrated that intra- and extracellular TGFs in 77N1 and NRK cells were immunologically identical or very closely related to each other and suggested the possibility that extracellular TGF from 77N1 cells was released into serum-free conditioned medium after formation of complex with other cellular components.

Animals↗
PubMed1985

Inhibitory effect of transforming growth factor-beta on DNA synthesis of adult rat hepatocytes in primary culture.

A transforming growth factor-beta (TGF-beta) found in platelets strongly inhibited DNA synthesis of adult rat hepatocytes in primary culture stimulated by insulin plus EGF or by hepatocyte growth factor (HGF) from rat platelets, but not the syntheses of secretory and intracellular proteins by the cells. TGF-beta had no cytotoxic effect, as judged by phase-contrast microscopic examination of the cell morphology. The inhibition of DNA synthesis by TGF-beta was correlated with marked decrease in the labeling index. TGF-beta did not inhibit growth of hepatoma cell line. These findings indicate that TGF-beta is a strong growth inhibitor of adult rat hepatocytes and may block their shift from the G1 phase to the S phase. The physiological role of TGF-beta in inhibiting growth of adult hepatocytes during liver regeneration is discussed.

Animals↗
PubMed1985

Casein and histone kinases of a rat ascites hepatoma as compared with those of rat liver.

Seryl/threonyl-protein kinases in cytosolic and particulate fractions from rat liver and AH-13, a rat ascites hepatoma, have been studied by chromatographing these fractions on DEAE-cellulose and assaying the eluates with casein, phosvitin, histone and protamine as substrates. Liver cytosolic fraction contains a group of well-characterized seryl/threonyl-protein kinases, namely, casein kinases I and II and histone kinases I and II. Liver particulate fraction, on the other hand, is almost totally devoid of casein kinase I and histone kinase I but contains an additional peak of casein kinase tentatively designated casein kinase III. In AH-13, cytosolic casein kinase I is markedly increased and particulate-associated casein kinases II and III are moderately increased as compared with liver. Moreover, it was found that in AH-13, the histone kinase I level is high in the particulate fraction but markedly decreased in the cytosolic fraction. It is suggested that particulate-associated histone kinase I may be of cytosolic origin.

Animals↗
PubMed1984

The purification of an acid- and heat-labile transforming growth factor from an avian sarcoma virus-transformed rat cell line.

A new class of transforming growth factor (TGF), with chemical characteristics differing from previously reported TGFs, was isolated and purified from an avian sarcoma virus-transformed rat cell line, 77N1 . Purification steps were simple and consisted of ion-exchange chromatography on diethylaminoethyl (DEAE)-Sephacel, ammonium sulfate precipitation, Chromatofocusing, and DEAE-Sephadex A-25 chromatography. The purified TGF is a heat- and acid-labile protein with a molecular mass of 12,000 daltons and isoelectric point of 5.2-5.4. Because of the acid lability of this TGF, purification was carried out at neutral pH. The TGF induced DNA synthesis in growth-arrested BALB 3T3 cells and promoted anchorage-independent growth of nontransformed BALB 3T3 cells in soft agar; the latter activity is specific for the peptide growth factors, called TGFs, but it did not compete with epidermal growth factor (EGF) for binding to the EGF membrane receptors. The TGF activity was not potentiated by EGF. The purified preparation of the TGF stimulated BALB 3T3 cells to grow progressively in soft agar at a dose of 20 ng/ml.

Amino Acids↗
PubMed1984

[Characterization of a transforming growth factor produced in rat cells transformed by an avian sarcoma virus].

Transformation of rat cells by avian sarcoma viruses (ASVs) induced the release of transforming growth factors (TGFs), which transiently promote anchorage-dependent untransformed BALB3T3 clone A31 cells to form progressively growing colonies in soft agar, into serum-free conditioned medium. A new class of TGF, which is a heat and acid-labile protein with a molecular mass of 12,000 daltons, was isolated and purified from an ASV-transformed rat cell line, 77N1, derived from NRK cells. The TGF from 77N1 did not bind to epidermal growth factor membrane receptors. We observed specific in vitro phosphorylation of several membrane proteins from A31 cells in the presence of the TGF.

Animals↗