Search PubMed⌕ Search

Biomedical subjects

S Kato

Publications and source records attributed to S Kato.

At least 1,387 records · Page 77Linked to original sources
PubMed1987

Analysis of Marek's disease virus serotype 1-specific phosphorylated polypeptides in virus-infected cells and Marek's disease lymphoblastoid cells.

By use of monoclonal antibodies, a virus-specific cytoplasmic antigen related to phosphorylated polypeptides specific to serotype 1 of Marek's disease virus (MDV)-related viruses (MDV1) has been identified in all MD tumour cell lines examined, as well as in infected cells and in tumour lesions of chickens with MD. At least two phosphorylated polypeptides with mol. wt. 39,000 (39K) to 36K and 24K (pp39/36 and pp24, respectively) were identified in the MD tumour cell line H10 cultured at 33 degrees C by immunoprecipitation with monoclonal antibody M21 which reacts with virus-specific phosphorylated polypeptides. These polypeptides were not detected in cells infected with MDV-related viruses of serotype 2 or 3. Immunoblot analysis indicated that these two polypeptides contained a serotype 1-specific epitope recognized with M21. An additional 41K polypeptide appeared in different virus strains of serotype 1. These polypeptides were found to contain phosphorylated serine but no detectable phosphorylated tyrosine or phosphorylated threonine. Cell fractionation indicated that the two phosphorylated polypeptides were mainly associated with smooth and rough endoplasmic reticulum fractions of cells infected with MDV1. Furthermore, the mRNA coding for pp39/36 could be separated from that coding for pp24 on a sucrose density gradient. These results suggest that pp24 and pp39/36 are translated from distinct mRNAs and encoded from overlapping genes or separate regions with partial DNA homology in the MDV1 genome.

Animals↗
PubMed1987

Methylation of Marek's disease virus DNA in chicken T-lymphoblastoid cell lines.

Methylation of Marek's disease virus serotype 1 (MDV1) DNA in both productively and latently infected cells was examined by restriction endonuclease analyses with the isoschizomeric pair HpaII and MspI. The latent MDV1 DNA in T-lymphoblastoid cell lines established from chicken T-lymphomas was considerably methylated, whereas methylation of the virus DNA sequences was not detected in productively infected cells.

5-Methylcytosine↗
PubMed1987

Sequences responsible for erythroid and lymphoid leukemia in the long terminal repeats of Friend-mink cell focus-forming and Moloney murine leukemia viruses.

Despite the high degree of homology (91%) between the nucleotide sequences of the Friend-mink cell focus-forming (MCF) and the Moloney murine leukemia virus (MuLV) genomic long terminal repeats (LTRs), the pathogenicities determined by the LTR sequences of the two viruses are quite different. Friend-MCF MuLV is an erythroid leukemia virus, and Moloney MuLV is a lymphoid leukemia virus. To map the LTR sequences responsible for the different disease specificities, we constructed nine viruses with LTRs recombinant between the Friend-MCF and Moloney MuLVs. Analysis of the leukemia induced with the recombinant viruses showed that a 195-base-pair nucleotide sequence, including a 75-base-pair nucleotide Moloney enhancer, is responsible for the tissue-specific leukemogenicity of Moloney MuLV. However, not only the enhancer but also its downstream sequences appear to be necessary. The Moloney virus enhancer and its downstream sequence exerted a dominant effect over that of the Friend-MCF virus, but the enhancer sequence alone did not. The results that three of the nine recombinant viruses induced both erythroid and lymphoid leukemias supported the hypothesis that multiple viral genetic determinants control both the ability to cause leukemia and the type of leukemia induced.

Animals↗
PubMed1987

Effects of pantoyl-GABA on GABAA and GABAB receptors in the rat brain.

The interactions of the "antidementia drug" pantoyl-gamma-aminobutyric acid (pantoyl-GABA) with gamma-aminobutyric acid (GABA) receptors were investigated by studies on bindings of radiolabelled ligands in rat brain. Pantoyl-GABA inhibited the binding of [3H]GABA to GABAA receptors and those of [3H]baclofen and [3H]GABA to GABAB receptors in the rat cerebral cortex. These data suggest that pantoyl-GABA interacts with both types of GABA-receptors in the rat brain.

Animals↗
PubMed1987

Effects of sodium vanadate on smooth muscles of guinea-pig ureter and their relation to extracellular Ca.

The effects of sodium vanadate on electrical and mechanical activities of the guinea-pig ureter were studied. Sodium vanadate at concentrations higher than 10(-5) M induced elevations of basal tension and repetitive twitch-like contractions. The drug depolarized membrane only slightly but induced repetitive action potentials. Sodium vanadate potentiated phasic and tonic contractions of K-contracture. It also increased tension development of high amplitude in K-depolarized preparations. Thus, the change in the resting membrane potential does not seem to play the only role in the initiation of contractions, though sodium vanadate-induced twitch-like contractions were associated by repetitive action potentials. Sodium vanadate-induced twitch-like contractions were blocked by Ca removal or by verapamil, but elevated basal tension was depressed only slightly under these treatments. Sodium vanadate induced tension development in the absence of Ca both in polarized and K-depolarized preparations. These results suggest that sodium vanadate increased mechanical activities by enhancing Ca influx as well as releasing intracellular bound Ca and/or inhibiting Ca extrusion through cell membrane.

Animals↗
PubMed1987

The vasculature of the guinea-pig thymus: topographic studies by light and electron microscopy.

The three-dimensional vascular distribution and the vascular-parenchymal relationship in normal guinea pig thymus were studied by light, scanning and transmission electron microscopy. Interlobular arteries arising from one thymic artery entered the thymic parenchyma where they branched into arterioles and then formed capillary networks in the cortex and in the medulla. Most cortical capillaries drained to the surface via perpendicular venules which merged into the subcapsular veins. Some vessels of the inner cortex, however, returned blood to the postcapillary venules (PCVs) at the cortico-medullary junction and in the medulla. The vascular supply of the guinea pig thymus is thus characterized by a dual circulation in which venous blood drains either via a subcapsular or via a cortico-medullary route. The endothelium of the postcapillary venule (PCV) was flat and often contained migrating lymphocytes. These venules were surrounded by a perivascular space (PVS) which separated the vessel from the parenchyma and which contained many lymphocytes. This PVS was not lined by cells but was delimited on one side by the abluminal surface of the venular endothelium and on the other side by a thin, sheet-like layer formed by cytoplasmic processes of epithelial reticular cells. This epithelial sheet was not continuous, as there were frequent interruptions or gaps where the PVS communicated directly with the intercellular mesh of the thymic parenchyma. The PVS did not form a continuous longitudinal channel but was interrupted by epithelial trabeculae. Some macrophages and a few plasma cells were seen in the parenchyma near the PVS. These findings suggest that the PCV and the PVS in the thymus may function as pathways for the migration of lymphocytes into or out of the blood circulation.

Animals↗
PubMed1987

Gonadal function in male patients with alcoholic and non-alcoholic liver disease.

Gonadal function in male patients with various liver disease has been evaluated by basal plasma testosterone level and a response of plasma testosterone to human chorionic gonadotropin. Compared with healthy male subjects of similar age, gonadal function was not reduced in chronic hepatitis, but in alcoholic liver disease without cirrhosis and in alcoholic and non-alcoholic cirrhosis. Gonadal dysfunction in patients with chronic hepatitis and cirrhosis was correlated with abnormal liver tests. It may be concluded that gonadal function in chronic liver disease is reduced either by alcohol abuse or disturbances of hepatic function and/or hepatic hemodynamics.

Aged↗
PubMed1987

Secretion of egg white proteins in primary cultured oviduct cells of laying Japanese quail (Coturnix coturnix japonica).

Oviduct (magnum) cells of laying Japanese quails (Coturnix coturnix japonica) were isolated after digestion of the magnum portion by collagenase and dispase and cultured in Dulbecco's modified Eagle medium (DME) supplemented with 10% fetal calf serum. The cultured cells formed a monolayer. Immunoperoxidase staining with antiovalbumin and anticonalbumin antibodies elucidated that more than 90% of the total population of the cells contained ovalbumin and conalbumin within the cytoplasm. The result shows that the cultured cells are composed mainly of tubular gland cells. Cells secreted ovalbumin and conalbumin continuously for several days. Secretion of these egg white proteins was confirmed to be inhibited by colchicine and vinblastine, which means that the microtubular system is involved in the secretion pathway of the proteins, as is widely accepted. Tunicamycin, an inhibitor of glycosylation of proteins, blocked the glycosylation of nascent ovalbumin molecules at a concentration of 5 micrograms/mL in the medium. However, immunoreactive ovalbumin was secreted under these conditions, without being glycosylated. This suggests that the carbohydrate moiety of ovalbumin is not essential for the secretion of ovalbumin. The secretion of ovalbumin was inhibited by brefeldin A, which is supposed to inhibit the transport of proteins from the rough endoplasmic reticulum to the Golgi apparatus. The present method of cultivating egg white-secreting cells will be useful in investigations of mechanisms and regulation of the synthesis and secretion of egg white proteins in birds.

Animals↗
PubMed1987

[Clinical statistics on outpatients at the Urological Clinic of Higashi Sapporo Sanjukai Hospital in 1985].

A statistical study was performed on new outpatients, the total number of which was 7,786 (male: 4,953, female: 2,833) in 1985. The male to female ratio was 1.75:1. They had urogenital diseases definitely diagnosed (6,786), tentatively diagnosed (600), normal (260), and diseases other than urogenital (140), and 36.2% of them had been referred to us by other sources. On these outpatients 206 operations had been performed circumcision, resection of condyloma and vasectomy were representative. The peak of the age distribution was in the thirties for males and in the twenties for females. For the first time in Japan, we treated renal and upper ureteral stones using extracorporeal shock wave lithotripsy (ESWL) on September 1, 1984. The results of ESWL at out hospital have been satisfactory. A statistical study was made on new outpatients according to the international disease classification. There were 152 malignant (urogenital) tumors (2.1%). The major diseases of the new outpatients were cystitis (acute or chronic: 20.6%), upper urinary tract stones (19.4%), prostatitis (13.5%), benign prostatic hypertrophy (10.7%). In males the major diseases were prostatitis, upper urinary tract stones, benign prostatic hypertrophy, balanoposthitis, and phimosis, and in females they were cystitis, upper urinary tract stone, pyelonephritis, and renoptosis. We conclude that our hospital plays a major role as a private urological hospital.

Adolescent↗
PubMed1987

Differential ability of tumor-unique and cross-reactive antigen(s) on two murine hepatoma cell lines to induce Lyt-1+2- T cells responsible for in vivo protective immunity.

The role of the tumor-unique determinant(s) on two syngeneic murine hepatoma cells in inducing in vivo protective immunity was investigated in comparison with that of the tumor-cross-reactive determinant(s). Induction of vaccinia-reactive helper T cells in C3H/He mice by intraperitoneal (i.p.) inoculation of viable vaccinia virus and then immunization with vaccinia-infected syngeneic MH134 or MH129 tumor cells resulted in the production of potent anti-MH134 or -MH129 antibody as well as the generation of in vivo protective immunity. Neither antibody reacted with other syngeneic plasmacytoma or fibrosarcoma cells, but both cross-reacted appreciably with the other hepatoma cells as well reacted strongly as with the tumor cells used for immunization. The absorptions of anti-MH134 and -MH129 antisera with the respective hepatoma cells abolished their reactivities with both the corresponding hepatoma cells and the other hepatoma cells. In contrast, the absorption of these antisera with the other tumor cells resulted in loss of their cross-reactivities with the other hepatoma cells, but not loss of their specific reactivity to the respective hepatoma cells. Although in these hematoma systems, the above-mentioned immunization protocol resulted in in vivo induction of protective immunity and generation of antibodies, in vivo immunity as observed by Winn assays was mediated by Lyt-1+2- T cells and was specific for each type of hepatoma cells. These results indicate that these two types of hepatoma cells bear two kinds of antigenic determinants, one kind unique to each hepatoma and the other kind cross-reactive with the other hepatoma cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗