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Biomedical subjects

T Nishihara

Publications and source records attributed to T Nishihara.

At least 271 records · Page 15Linked to original sources
PubMed1983

Localization of the Q beta replicase recognition site in MDV-1 RNA.

Fragments of MDV-1 RNA (a small, naturally occurring template for Q beta replicase) that were missing nucleotides at either their 5' end or their 3' end were still able to form a complex with Q beta replicase. By assaying the binding ability of fragments of different length, it was established that the binding site for Q beta replicase is determined by nucleotide sequences that are located near the middle of MDV-1 RNA. Fragments missing nucleotides at their 5' end were able to serve as templates for the synthesis of complementary strands, but fragments missing nucleotides at their 3' end were inactive, indicating that the 3'-terminal region of the template is required for the initiation of RNA synthesis. The nucleotide sequences of both the 3' terminus and the central binding region of MDV-1 (+) RNA are almost identical to sequences at the 3' terminus and at an internal region of Q beta (-) RNA.

Base Sequence↗
PubMed1983

Effect of cyclophosphamide on murine nephrotoxic nephritis.

We studied the effect of cyclophosphamide (CPM) on development of severe glomerular lesions in a model of murine nephrotoxic nephritis (NTN). CPM treatment (300 mg/kg) before initiation of the first phase on NTN showed no host antibody depositions along the glomerular basement membrane, as revealed by immunofluorescence; however, the histological study revealed no significant difference in the degree of renal damage between the control and the CPM-treated mice. Therefore, the severe glomerular lesions in murine NTN may be induced without antibody response to nephrotoxin, in the glomerulus.

Animals↗
PubMed1983

Full and empty particles of hepatitis B virus in hepatocytes from patients with HBsAg-positive chronic active hepatitis.

Complete and defective hepatitis B virus (HBV) particles in sera and hepatocytes were observed by electron microscopy for an understanding of the maturation process of hepatitis B virus. To distinguish Dane particles with or without DNA on the basis of staining density with uranyl acetate, Dane particles, purified from sera of asymptomatic carriers, and Dane particle cores, separated by ultracentrifugation in a metrizamide density gradient, were observed by electron microscopy. Complete cores at a low density (1.19 to 1.23 gm/cm3) were electron dense and incomplete cores at a high density (1.23 to 1.27 gm/cm3) were partially electron dense or empty. These findings demonstrated that the presence or absence of DNA is reflected by the electron density of the core. Our result, in which less than 10% serum Dane particles have full cores in ultrathin sections of the pellet, is in agreement with Gerin's finding that defective Dane particles are predominent in sera. Naked core particles and Dane particles in two biopsy specimens from patients with hepatitis B surface antigen, hepatitis B e antigen, and DNA polymerase-positive, chronic active hepatitis were classified into complete versus incomplete particles on the basis of electron density. Nine hundred and fourteen naked core particles were detected in nuclei and cytosol of 68 hepatocytes. One hundred and five core particles (11.5%) were electron dense and 809 core particles (88.5%) were partially electron dense or empty. Furthermore, 488 Dane particles were observed in the cisternae of the endoplasmic reticulum of these hepatocytes. Fifty Dane particles (10.2%) had full cores, and 438 Dane particles (89.8%) had partially full or empty cores. These findings suggest that DNA may be incorporated into about 1 to 10% of core particles when they are assembled in nuclei of hepatocytes. Morphologic differences in damage to hepatocytes containing various frequencies of full Dane particles were also studied, but no significant correlation was found between damage in hepatocytes and frequency of full Dane particles.

Hepatitis B Surface Antigens↗
PubMed1982

Needle-shaped inclusions in plasma cells in a patient with hypogammaglobulinemia.

A case of a patient with needle-shaped inclusions in plasma cells was reported. Some of the inclusions were positively stained for acid phosphatase and beta-glucuronidase. Ultrastructurally, each inclusion was surrounded by a single limiting membrane without any relation to rough-surfaced endoplasmic reticulum and composed of numerous fine fibrous bundles. By the enzyme-labeled antibody technic, the inclusions were found as "stain defects" in IgG-forming plasma cells, but not in IgM-forming plasma cells. Although the exact nature of the inclusions could not be clarified, they were quite different from both amyloid fibrils and immunoglobulin-derived inclusions, and were thought to be synthesized by a clone of differentiated plasma cells. The patient showed moderate hypogammaglobulinemia but no evidence of a direct correlation between the inclusions and hypogammaglobulinemia was obtained. Though the possibility that the case was non-secretory myeloma could not be ruled out, it was unlikely judged by the findings of various examinations.

Agammaglobulinemia↗
PubMed1982

Identification of taurine occurring sporulating cells of Bacillus subtilis.

An unidentified ninhydrin-positive substance was detected in trichloroacetic acid extract from the sporulating cells of Bacillus subtilis NRRL B558. The substance was isolated as the corresponding 2,4-dinitrophenyl (DNP) derivative, the structure of which was identified with a pyridinium salt of DNP-taurine, based on spectral and synthetic evidence. a pyridine molecule should be introduced into a taurine molecule during the isolation procedure and hence, the original amino acid was assigned to taurine. Taurine was accumulated into the cells from the medium during the early stages os sporulation, and thereafter metabolized or excreted.

Bacillus subtilis↗
PubMed1982

Central pontine myelinolysis: an immunofluorescent study.

A young pregnant woman showing clinical symptoms of numbness, vertigo, diplopia, and amnesia with associated hypernatremia ran a fulminant course. At autopsy, an area or extensive demyelination in the center of the pons was found and a pathological diagnosis of central pontine myelinolysis was made. Since definitive etiology and pathogenesis of the lesion have not been established, we investigated the role of humoral immunity in the pathogenesis of this condition by retrospective immunofluorescent study; the result was negative. Possible factors related to the etiology and pathogenesis of the lesion in this case are discussed.

Adult↗
PubMed1982

Electron and immunoelectron microscopic study of Dane particle formation in chronic hepatitis B virus infection.

The site of Dane particle formation in hepatocytes was studied by routine electron and immunoelectron microscopy of liver biopsy specimens from 10 patients with hepatitis B e antigen-positive chronic active hepatitis. With routine electron microscopy, core particles were abundant in cytosol, often adjacent to the cell membrane, and occasionally in the microvilli. Figures suggestive of budding of endoplasmic reticulum with a core particle into the cisternae of endoplasmic reticulum were observed frequently. There were also figures suggestive of direct budding with a core particle from the surface of the cell. With the immunoelectron microscopy, the core particles were found to be positive for hepatitis B core antigen and the endoplasmic reticulum and the plasma membrane were positive for hepatitis B surface antigen. These findings suggest that the most plausible mode of formation of the Dane particle is by budding of hepatitis B surface antigen-positive endoplasmic reticulum membrane into the cisternae. In addition, formation of the Dane particle may also take place at the surface of the hepatocyte by a similar mechanism.

Cell Membrane↗
PubMed1981

Studies on the bacterial spore coat. IX. The role of surface charge in germination of Bacillus megaterium spores.

The surface charge of Bacillus megaterium QM B1551 spores was estimated to be negative, -0.2 ad -0.4 mueq/mg by colloidal titration using glycol chitosan (GCh) and methylglycol chitosan (MGCh), respectively, as positive colloids. MGCh, which reacts with all of the negatively charged groups including carboxylate, inhibited the second stage of the germination to result in semirefractile spores, but GCh, which reacts only with strong acidic groups such as phosphate, did not. The spores produced in a medium with limited phosphate had coats with low phosphate content and carried less negative charge, and they were induced to germinate with 0.4 mM KNO3, which is one-tenth of the minimum concentration required for the germination of the control spores. A similar increase in germinability was observed in spores incubated with calcium acetate. The results suggest that the role of the surface charge in germination is as follows. Strong acidic groups (such as phosphate) in the coat may block the action of ionic germinants and act as a barrier against the initiation of ionic germination. Positively charged compounds (such as calcium) may compensate for this blocking effect. Weak acidic groups (such as carboxylate) may be involved in the later stage of germination.

Bacillus megaterium↗
PubMed1981

Masugi nephritis produced by the antiserum to heterologous glomerular basement membrane. I. Results in mice.

Nephrotoxic activity of rabbit antisera to glomerular basement membrane (GBM) from three different donors (rat, gerbil, and man) was examined in mice of various strains. Animals receiving a small dose (0.1 ml) of anti-rat GBM or a large dose (0.3 ml X 2) of anti-gerbil GBM developed massive proteinuria and irreversible glomerular lesions which were identical to those seen in rats receiving anti-rat GBM, i.e. rat Masugi nephritis. Linear deposition of rabbit IgG, host's immunoglobulins and C3 was characteristically seen. Necrotizing changes and crescent formation accompanied by plasmic exudation, cellular proliferation and/or infiltration of PMNs and monocytes occurred after the injection. In animals receiving anti-human GBM, linear deposition of rabbit IgG and less marked glomerular changes were seen. The finding of no specificity in species between GBM antigens of rat and mouse indicates the usefulness of rat GBM for mouse Masugi nephritis or anti-GBM disease.

Animals↗