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Biomedical subjects

R Hirai

Publications and source records attributed to R Hirai.

53 records · Page 3Linked to original sources
PubMed1983

Isolation and partial purification of a new class of transforming growth factors from an avian sarcoma virus-transformed rat cell line.

Transformation of rat cells by avian sarcoma viruses induced the release of growth factors into serum-free conditioned medium. An avian sarcoma virus-transformed rat cell line, 77N1, produced and released a polypeptide growth factor, classified as a transforming growth factor (TGF), which transiently promotes anchorage-dependent BALB3T3 A31 cells to form progressively growing colonies in soft agar. The TGF was isolated and partially purified from an extract of 77N1 cells by ion-exchange chromatography on a diethylaminoethyl Sephacel column followed by ammonium sulfate precipitation. The TGF was assumed to have a molecular weight of 11,000 from gel filtration on Sephadex G-50. This TGF did not compete with epidermal growth factor for binding to cell membrane receptors and was not potentiated by epidermal growth factor. The TGF was trypsin and dithiothreitol sensitive as well as heat and acid labile, indicating that it was different from previously reported TGFs of similar molecular weight and thus belonged to a new class of TGFs.

Animals↗
PubMed1983

[Adenomatous changes in the thyroid gland detected upon autopsy].

Of 820 autopsy individuals without clinical abnormalities, 218 (26.6%) revealed adenomatous goiter-like thyroid changes. The incidence was higher in females, it increased with age, however, there was no regulation to the disease which was the cause of death. In 12 cases there was association with microcancer. The 218 subjects were divided into 3 groups designated as mild, moderate and severe stages, according to the degree of change. The severe group is regarded as subclinical cases of adenomatous goiter. In the mild and moderate group, the possibility fo early figures of adenomatous goiter may be undeniable; degenerative changes due to aging appear to have an effect.

Adenoma↗
PubMed1980

The synthesis of the cystine-rich proteins in rat epidermis: I. Analysis by [35S]cystine incorporation.

Three-day-old Sprague-Dawley rats were injected intraperitoneally with 100 muCi of [35S]cystine. They were then sacrificed at 30 minutes, 2, 4, and 10 hours. The skins were epilated by the beeswax-resin procedure and the epidermis was separated by soaking in NH4Cl solution. Neither hair with hair follicles nor hair sheath was attached to the epidermal sheets after the epilation. Keratohyalin granules were solubilized after the freezing and thawing procedure. Living cell layers were separated from stratum corneum following further incubation in NH4Cl solution. Both the living cell layers and the stratum corneum were extracted with 8 M alkaline urea. Seventy-two to 92% of the total radioactivity incorporated into epidermal proteins was found in the urea-insoluble fraction of the stratum corneum. Only 2.4 to 6.4% of the total radioactivity was incorporated into the keratohyalin granular fraction. The specific radioactivity which was incorporated into the urea-insoluble fraction of the stratum corneum was still increasing 10 hours after injection, though the radioactivity in other fractions was decreasing at 10 hours following injection. The highest specific radioactivity of [35S]cystine was found in the urea-soluble fraction of the living cell layers, and was being rapidly turned over.

Animals↗
PubMed1980

Double transformation of Indian muntjac cells by avian and murine sarcoma viruses.

Avian sarcoma virus-transformed Indian muntjac cells, SR-Mm-1, formed foci by murine sarcoma-xenotropic murine leukemia virus complex [MSV(X-MuLV)] superinfection. The response of SR-Mm-1 and parental normal Indian muntjac Mm-2K cells to MSV(X-MuLV) infection was compared. Focus formation by MSV(X-MuLV) followed two-hit kinetics in Mm-2K, but one-hit kinetics in SR-Mm-1 cells. MSV(X-MuLV)-infected SR-Mm-1 cells formed larger colonies than uninfected SR-Mm-1 cells in soft agar, while no colony was formed in the MSV(X-MuLV)-infected Mm-2K cells. After infection with MSV(X-MuLV), cell clones doubly transformed by avian and murine sarcoma viruses could be established in SR-Mm-1 cells, whereas no cell clone could be established in Mm-2K cells. The doubly transformed cells were more round and refractile than SR-Mm-1 cells. No specific chromosomal change could be detected among Mm-2K, SR-Mm-1, and the doubly transformed cells. By two-dimensional polyacrylamide gel electrophoresis of cellular proteins, several changes were seen between Mm-2K and SR-Mm-1 cells. In MSV(X-MuLV)-infected Mm-2K and SR-Mm-1 cells, several similar changes in polypeptide patterns were seen as compared with uninfected cells. These results indicate that Mm-2K cells were doubly transformed by avian and murine sarcoma viruses, and MSV transformation in SR-Mm-1 cells was different from that in Mm-2K cells.

Animals↗
PubMed1978

Electron microscopic changes of keratohyalin granules during the freezing and thawing procedure.

After 3-day-old rat skins were treated by freezing and thawing procedures, small empty spaces were formed both in keratohyalin granules and in the cytoplasm of the granular cells. When the skin specimens thus treated were further incubated in 50 mM Tris-HCl buffer, pH 8.6, for 15 min, keratohyalin granules were solubilized, leaving electron dense rims. Small electron dense or less dense particles were detaching from these rims. Cell membranes were also disrupted at various regions. Desmosomal structures in the stratum granulosum cells were all preserved.

Animals↗
PubMed1978

Transformation of Indian muntjac cells by murine and avian sarcoma viruses.

Indian muntjac cells were efficiently transformed by murine sarcoma virus (MSV) and avian sarcoma viruses (ASV). When colony formation of the infected cells was examined in soft agar, many colonies were formed by the ASV-injected cells but no colony was seen in the MSV-infected cells. The ASV-transformed cell clones differed among the clones in morphology, presence of inducible ASV genome, and karyotypes.

Alpharetrovirus↗
PubMed1978

The constituents of keratohyalin granules of newborn rat epidermis under an electron microscopy.

Three-day-old rat skins were treated either by the freezing--thawing method or by the tetraphenylboron technique. After the former procedure, keratohyalin granules were solubilized, leaving empty spaces with an electron-dense or less dense rim. Particles roughly 200 A in diameter, which were either electron-dense or less dense, were observed in the empty spaces and also seen detaching from the rim. After the freeze--thaw procedure, two types of keratohyalin granule were observed. The one is the same electron-dense granule as keratohyalin granules in vivo and the other is the granule, the electron density of which was identical with tonofilaments. Both granules were granular rather than fibrous in structure.

Animals↗
PubMed1978

The fluroescent profiles of keratohyalin granules of newborn rat epidermis with a new fluorescent thiol reagent (DACM).

A highly specific fluorescent thiol reagent, N-(7-Dimethylamino-4-methyl-coumarinyl)maleimide (DACM) has been used to examine the newborn rat skin in order to elucidate the cystine-rich keratohyalin granules or dense homogeneous deposits. After reduction of the disulphide bond with 2-mercaptoethanol, the periphery of the stratum corneum cells showed a very distinct fluorescence and the cytoplasm of the stratum corneum, granulosum and spinulosum showed moderate fluorescence. No fluorescence was observed, however, over the keratohyalin granules themselves. Intense, spotty fluorescence was observed from the remnants of nuclei and at the periphery of large keratohyalin granules of the stratum granulosum cells, which were assumed to be dense homogeneous deposts according to their distribution pattern. As the intense fluorescence elicited with DACM determines the abundance of cystine content in the material, cystine was found to be very scarce in keratohyalin granules, but abundant in dense homogeneous deposits and at the periphery of the stratum corneum cells.

Animals↗
PubMedDate not supplied

Attenuation of liver and lung injury after hepatic ischemia and reperfusion by a cytokine-suppressive agent, FR167653.

BACKGROUND: Hepatic ischemia/reperfusion (I/R) injury is an important clinical problem and leads to the release of the proinflammatory cytokines, TNF-alpha and IL-1. These cytokines play important roles in the induction of polymorphonuclear neutrophil (PMN) activation and infiltration, and induce not only localized hepatic injury but also remote organ injury, especially pulmonary injury. Using a total hepatic ischemia model in rats, we tested our hypothesis that suppression of TNF-alpha and IL-1 by FR167653 ameliorates I/R injury in the liver and lung. METHODS: Male Wistar rats, weighing 240-280 g, were divided into 3 groups, an FR group, a control group and a sham group. In the FR group, FR167653 (1 mg/kg/h) was administered continuously to the animals for 30 min prior to the onset of ischemia and for 2 h after reperfusion. The control group received normal saline. A porto-systemic shunt was placed between the cecal branch of the portal vein and the jugular vein, and total hepatic ischemia was produced for 90 min. The sham group was treated with placement of the porto-systemic shunt only. The 1-week survival rate, liver enzyme activity, hepatic tissue blood flow (HTBF), cytokine mRNA expression, myeloperoxidase (MPO) activity and histological results were studied. RESULTS: The 1-week survival rate and HTBF were significantly higher in the FR group than in the control group. Serum AST, ALT, and LDH levels were significantly lower in the FR group at 30 min, 1 h and 3 h after reperfusion. MPO levels in liver and lung tissue were also significantly lower in the FR group. The expression of IL-1beta mRNA remarkably decreased up to 6 h after reperfusion in the FR group. CONCLUSIONS: We concluded that the inflammatory cytokines, IL-1beta, play important roles in hepatic I/R injury. FR167653 might ameliorate I/R injury and be useful in liver surgery with ischemia.

Animals↗
PubMedDate not supplied

Enhanced expression of cyclin E and cyclin A in human hepatocellular carcinomas.

BACKGROUND: Disruption of the G1/S check point leads to uncontrolled cell growth, resulting in the development of cancers. MATERIALS AND METHODS: Cell cycle regulatory molecules were investigated in 33 surgically resected hepatocellular carcinoma (HCC) samples from 30 patients by Western blotting. RESULTS: Enhanced expressions of cyclin E and cyclin A were detected at frequencies of 18/33 and 26/33 in HCCs, respectively, as compared with their neighboring noncancerous tissues. The enhanced expression of cyclin E, but not that of cyclin A, correlated with hyperphosphorylation of pRb and high frequency of Ki-67-positive cells. Thus, the HCCs with enhanced cyclin E expression probably contain a relatively large number of proliferating cancer cells. CONCLUSIONS: The degree of cyclin E expression can be used as a prognostic parameter of HCC. In addition, cyclin E may become a molecular target in the treatment of HCCs.

Aged↗
PubMedDate not supplied

Inhibition of ubiquitin-ATP-dependent proteolysis and ubiquitination by cisplatin.

We tested the inhibitory activity of various antitumor agents on the ubiquitin-ATP-dependent proteolytic activity in rabbit reticulocyte lysates. We found that cisplatin, 4'-(9-acridinyl-amino) methanesulfon-m-anisidide (m-AMSA) and mitomycin C inhibited the ubiquitin-ATP-dependent proteolysis. IC50 values (50% inhibition concentrations) of these antitumor agents were 90, 210 and above 290 microM, respectively. Furthermore, cisplatin was found to inhibit the conjugation of ubiquitin to endogenous proteins in fraction II at 100 and 330 microM. These results suggest that cisplatin interacts with the enzyme(s) involved in ubiquitin conjugation and thus inhibits the ubiquitin-ATP-dependent protein degradation. We assume that the agents that can affect the ubiquitin system might be useful for the treatment of tumors and that the ubiquitin system could be a new target for cancer chemotherapy.

Amsacrine↗