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Y Natori

Publications and source records attributed to Y Natori.

At least 127 records · Page 7Linked to original sources
PubMed1988

Effect of cycloheximide on the levels of nuclear HMG proteins in rat liver.

Within 30 minutes of administration of cycloheximide to rats, rRNA synthesis in isolated liver nuclei was inhibited by approximately 50%. The nuclear contents of high mobility group (HMG) proteins, including HMG 1, 2 and 14, were found to be decreased in parallel with the inhibition of RNA synthesis while the contents of the total cellular HMG proteins remained unchanged. The role of HMG proteins in the regulation of RNA synthesis is discussed.

Amanitins↗
PubMed1987

Purification and characterization of a neutral protease from rat-liver cytosolic fraction.

Rat liver cytosol contains a neutral protease which degrades acetylated hemoglobin and some urea-denatured proteins maximally at pH 7.5. The enzyme was purified to homogeneity by conventional chromatographic techniques. It appears to be a metalloprotease since it is inhibited by EDTA and o-phenanthroline, the metal-depleted enzyme can be reactivated by Co2+, Zn2+, Mn2+, or Mg2+, and it is not inhibited by reagents specific for carboxyl, seryl, or thiol proteases. The enzyme has an apparent molecular weight of 200,000 as determined on Sephacryl S-200 column chromatography, and electrophoresis in sodium dodecyl sulfate showed 3 protein bands corresponding to the molecular weights of 110,000, 74,000, and 40,000.

Animals↗
PubMed1987

Nephritogenic glycoprotein. XII. Focal glomerulonephritis with myeloid bodies produced in rats by synthetic analogues of the glycopeptide, nephritogenoside.

Glomerular lesions were successfully induced in rats by a single footpad injection of synthetic analogues of nephritogenoside [alpha-Glc-(1----6)-alpha-Glc-(1-NHCO-Asn, and -Gln)]. Characteristic morphological changes of these glomerular lesions are (1) focal glomerulonephritis (FGN) and (2) the appearance of myeloid bodies in the epithelial cells of the podocytes. FGN produced by a single injection of the synthetic analogues of nephritogenoside may provide an experimental animal model of this potentially diffuse disease, since morphological changes in the early stage of sclerosing glomerulonephritis (end-stage kidney) induced by a single footpad injection of natural nephritogenoside are often identical to those of FGN.

Animals↗
PubMed1987

Nephritogenic glycoprotein. VIII. Isolation and partial characterization of nephritogenic glycopeptide (nephritogenoside) from the terminal chorionic villus of human placenta.

A glycopeptide comparable to human renal nephritogenic glycopeptide (nephritogenoside) of glomerular basement membrane (GBM) origin was isolated and purified from human placenta. Trophoblast basement membranes (TrBM) were isolated from placental terminal villi by ultrasonic disruption, and digested with trypsin and then with pronase. TrBM were then fractionated by zone electrophoresis, concanavalin A (Con A) affinity column chromatography and Bio-Gel P200 column chromatography. From 250 g (wet weight) of human placental terminal villi, we obtained a purified sample of 0.7 mg (dry weight) of glycopeptide. Ouchterlony gel diffusion demonstrated the existence of a common precipitin line between purified human placental glycopeptide and antiserum against human renal nephritogenic glycopeptide prepared from GBM. The sugar composition of this glycopeptide was rich in glucose (glucose, galactose and mannose were in the ratio of 1.00:0.30:0.33) and the amino acid composition of this glycopeptide contained no collagenous components. These results indicate that at least one of the nephritogenic substances common to the placenta and kidney is a glycoprotein rich in glucose and different from the collagenous component of the basement membrane.

Basement Membrane↗
PubMed1987

Effect of enrichment of infusion solutions with branched chain amino acids in parenteral nutrition of rats.

The effect of enrichment of the branched chain amino acids (BCAAs) leucine, isoleucine and valine on total parenteral nutrition was studied in rats. Experimental infusion solutions with a sufficient, marginal or deficient level of glucose contained either the conventional amino acid composition (22.6% BCAAs) or a BCAA-enriched amino acid composition (36% BCAAs). Rats were infused with experimental solutions for 4 days and several parameters of protein metabolism were evaluated in various tissues. Under conditions of sufficient energy supply, BCAA-enriched and conventional groups showed similar body weight gains and muscle protein degradations as measured by urinary 3-methylhistidine excretion. Polysome profiles in the liver and gastrocnemius muscle of the BCAA-enriched group were more heavily aggregated than those of the conventional group. Under the conditions of marginal or deficient energy supply, beneficial effects of BCAA enrichment over the conventional amino acid composition became more evident in terms of better body weight retention, higher RNA/DNA ratio and heavier polysome profile in both liver and muscle, and reduced protein catabolism in muscle. The present study suggests that enrichment of BCAAs, particularly valine and isoleucine, may be useful for nutritional support under hypercatabolic or stressed conditions.

Amino Acids, Branched-Chain↗
PubMed1987

Heymann nephritis in rats induced by human renal tubular antigens: characterization of antigen and antibody specificities.

An injection of human renal tubular fraction, Fx1A, with Freund's complete adjuvant in rats induces Heymann nephritis (HN) with clinical and morphological features similar to rat Fx1A-induced HN. The present study was undertaken to characterize antibody specificities and the corresponding antigen involved in human Fx1A-induced HN. In sera of rats immunized with human Fx1A, not only anti-human Fx1A antibody but also antirat Fx1A antibody was detected by enzyme immunoassay. Eluted antibody from the glomeruli also showed both activities. In an inhibition study of enzyme immunoassay, binding of the eluted antibody to human Fx1A was inhibited by both human and rat Fx1A and also by partially purified gp330, but not by purified gp108. Furthermore, binding of the eluted antibody to rat Fx1A was inhibited by both rat and human Fx1A. On immunoblot, the eluted antibody mainly reacted with a 440 kD glycoprotein of human Fx1A which showed the same mobility as rat gp330. The antibody also reacted with a band of gp330 of rat Fx1A. These results indicate that the 440 kD glycoprotein in humans is a counterpart of rat gp330 and that the eluted antibody has dual specificities to both human 440 kD glycoprotein and rat gp330, suggesting that the cross-reactive antibody is responsible for human Fx1A-induced HN.

Animals↗
PubMed1987

Identification of gp108, a pathogenic antigen of passive Heymann nephritis, as dipeptidyl peptidase IV.

Our previous paper showed that the glycoprotein of Mr 108,000 (gp108) is one of the major components of rat renal tubular brush border antigens and that an injection of anti-gp108 antiserum in rats induces passive Heymann nephritis with acute and severe proteinuria. In this study, gp108 was identified as a monomer of dipeptidyl peptidase IV (DPP IV). The anti-gp108 antibody was shown to immunoprecipitate DPP IV from Triton-extract of renal tubular membrane fractions. DPP IV was co-purified with gp108 from the Triton-extract by columns of DEAE-cellulose and Bio-gel A-1.5 m. The ratio of DPP IV activity and gp108 content was nearly constant throughout the purification steps. The final purified gp108 showed a high specific activity of DPP IV, comparable to that reported for purified rat DPP IV. These results indicate that gp108 is a monomer of DPP IV.

Animals↗
PubMed1987

The detection and characterization of renal brush border antigen (gp108) in various rat tissues.

We recently reported that an injection of antibody raised against renal brush border glycoprotein, gp108, in rats induced passive Heymann nephritis with acute and severe proteinuria. In this study, the distribution of gp108 in various rat tissues was investigated. On enzyme immunoassay, anti-gp108 antibody reacted to extracts of small intestine, lung, spleen, thymus, liver, epididymis, stomach, pancreas and heart. It also reacted to sera and extracts of peripheral blood cells, especially lymphocytes. These antigens, which are cross-reactive to kidney gp108 have similar biochemical properties: a molecular weight of about 108,000 and an isoelectric point of 4.8-5.4. These results show that immunologically and biochemically related antigens to renal glycoprotein, gp108, are present in various rat tissues.

Animals↗
PubMed1986

Clinical investigation of vestibular damage by antituberculous drugs.

Vestibular function testing was done regularly on the cases given streptomycin, kanamycin, or enviomycin and a method to detect the cases of vestibular dysfunction at an early stage was discussed, as well as the time these drugs should be discontinued. Subjects were 85 cases of tuberculosis treated with streptomycin, kanamycin, or enviomycin who were admitted to our hospital from December 1984 to May 1986. The method of equilibrium examination performed at regular intervals is as follows: standing test (Romberg test), stepping test, and Meyer zum Gottesberge's head-shaking test were done once a week for a month after starting antituberculous injections and they were re-examined once every 2 weeks for at least 3 months after beginning the injections. After the 3 months these tests were done once a month. Eight cases of vestibular damage due to streptomycin or enviomycin could be easily detected at an early stage by performing Meyer zum Gottesberge's head-shaking test, together with the standing test and the stepping test. Vestibular dysfunction is apt to occur after about 1 month or within a month from the start of daily injections especially with streptomycin. Therefore, the method of equilibrium examination, we suggest, is that the Meyer zum Gottesberge's head-shaking test, the standing test (Romberg test), and the stepping test should be performed once a week during the first month after the start of this drug. When the result of the Meyer zum Gottesberge's head-shaking test is less than 50% and swaying and/or rotation occur in the stepping test, the drugs being given should be discontinued.

Aged↗
PubMed1986

Comparison of nephritogenic glycopeptide, nephritogenoside, isolated from rat glomerular basement membranes with other basement membrane components.

Nephritogenic glycopeptide, nephritogenoside, is a minor component of basement membranes (the yield: 2-3 micrograms/kidney), and in homologous animals causes chronic glomerulonephritis. Nephritogenoside was compared to other basement membrane components including collagenous and noncollagenous glycoproteins. In limited pepsin digests of rat renal cortices, nephritogenoside was separable from type IV collagen by DEAE-cellulose column chromatography, although these two substances showed immunological cross-reactivity each other. Nephritogenoside did not immunologically cross-react with laminin and fibronectin by direct or inhibition enzyme immunoassay. These results indicate that nephritogenoside is different from basement membrane glycoproteins such as laminin and fibronectin and that nephritogenoside can be isolated from type IV collagen.

Animals↗
PubMed1986

Effects of glucose and amino acid depletions on protein synthetic parameters in liver and skeletal muscle of rats during parenteral nutrition.

Rats were nourished by intravenous infusion of four different experimental solutions: total parenteral nutrition (TPN) solution (group I); glucose-depleted TPN solution (group II); amino acid-depleted TPN solution (group III); and glucose- and amino acid-depleted TPN solution (group IV). All except group I animals lost body weight and showed negative nitrogen balance during a 7-day experimental period; glucose-depleted groups II and IV generally suffered more severely than amino acid-depleted group III. However, the concentration of plasma albumin in group III was significantly lower than that in the other groups. The weights of liver and gastrocnemius muscles after 7 days of infusion with different nutrient compositions were fairly well correlated with the RNA/DNA ratios in these tissues. Infusion of nutritionally deficient solutions caused progressive disaggregation of polysomes in both liver and gastrocnemius muscles, indicating variable degrees of impairment of protein synthesis in these tissues. The changes in polysomal profiles were rapid and sensitive; the polysomal disaggregation was evident within one day of infusion with deficient solutions. The determination of polysomal profiles in various tissues may be useful in optimizing the composition of TPN solutions.

Amino Acids↗
PubMed1986

Passive Heymann nephritis with acute and severe proteinuria induced by heterologous antibody against renal tubular brush border glycoprotein gp108.

Passive Heymann nephritis with acute and severe proteinuria was produced in rats by a single injection of heterologous antibody against a purified glycoprotein which consisted of homologous subunits with a molecular weight of 108,000 (gp108). Gp108 was identified as one of the major antigens in rat renal tubular fraction (FX1A) on immunoblotting assay by using total proteins of FX1A and rabbit antiserum against FX1A. A band of gp330, which was identified as a pathogenic antigen of Heymann nephritis by Kerjaschki D and Farquhar MG (Proc Natl Acad Sci USA 79:5557, 1982) was detected as another band by Coomassie blue staining and immunoblotting. Autoantibodies in the sera of FX1A-injected (active Heymann nephritis) rats reacted to the band of gp330 but not to gp108. These results indicate that gp108 is a different glycoprotein from both gp330 and its degradation products. GP108 was subsequently purified to near homogeneity by extraction with Triton X-100, and then DEAE-cellulose and Bio-Gel A-1.5m column chromatographies. On gel permeation chromatography, the purified antigen showed a molecular weight of 310,000, suggesting that it consists of dimer or trimer of gp108. Rabbits immunized with gp108 produced an antibody which showed monospecific binding to gp108. The antibody stained with brush border of proximal renal tubules in addition to the capillary loops in rat glomeruli by indirect immunofluorescence. Injection of rabbit antiserum against gp108 in rats induced severe proteinuria within 2 days. On the 2nd day after the injection, the glomeruli of the animals showed granular immune deposits along the capillary loops in addition to dominant staining of the brush border of the proximal tubules by immunofluorescence. These results indicate that gp108 is a pathogenic antigen in passive Heymann nephritis and that an antibody against gp108 has a nephritogenic and proteinuria-inducing activity.

Acute Disease↗
PubMed1985

Enhancement of RNA synthesis in chick liver by food intake: possible role of high mobility group nonhistone proteins.

RNA synthesis in the nuclei of liver from newly hatched (4-d-old) chicks is enhanced by intake of food. The enhanced synthesis was ascribed not to an increase in the activity of solubilized DNA-dependent RNA polymerase but to an increase in the initiation of RNA synthesis. Enhanced RNA synthesis in fed chicks was accompanied by greater susceptibility of nuclei to digestion by micrococcal nuclease. Salt extraction abolished the difference in nuclease sensitivity between the fed and fasted groups. Reconstitution with either 0.35 M NaCl extracts or high mobility group (HMG) nonhistone proteins restored digestion susceptibility, but changing the source of extracted proteins did not equalize the extent of digestion in nuclei from livers of fed and fasted chicks. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of HMG proteins revealed the presence of HMGs 1 and 2 as well as a 38,000-dalton protein. The nuclear HMG protein content in fed chicks was greater than that of fasted chicks (121 +/- 17 micrograms/mg DNA vs. 31 +/- 12 micrograms/mg DNA). The electron microscopic examination of hepatocyte nuclei revealed the enlargment of nucleoli and scarcity of aggregated heterochromatin structures in the fed chicks as compared with the fasted chicks. These morphological features are compatible with the high transcriptional activity in liver of fed chicks.

Animals↗
PubMed1985

Intracellular phospholipase activities of Tetrahymena pyriformis.

Phospholipase activity was studied in the protozoan Tetrahymena pyriformis NT-1 by using exogenous phosphatidylethanolamine and phosphatidylcholine. Several phospholipase activities were found in Tetrahymena homogenates. They were distinguished with respect to pH optimum, activity dependence on Ca2+, substrate specificity and positional specificity. Ca2+-Dependent phospholipase activity had an optimal pH around 9 and gave rise to free fatty acid and lysophospholipid. This enzyme hydrolyzes phosphatidylethanolamine but not phosphatidylcholine. The alkaline phospholipase with A1 activity was located mainly in the surface membrane (pellicle fraction). The enzyme activity had a pH optimum ranging from 8 to 9, and required 2 mM CaCl2 for the maximal activity. All detergents tested inhibited the enzyme activity. Ca2+-Independent phospholipase activity had an optimal pH from 4 to 5 and gave rise to free fatty acid, lysophospholipid, diacylglycerol, and monoacylglycerol. We concluded that there are at least three phospholipase in Tetrahymena homogenates, i.e., alkaline phospholipase A and acidic phospholipases A and C.

Animals↗
PubMed1984

A simple procedure for the isolation of highly purified lysosomes from normal rat liver.

A procedure for the isolation of highly purified lysosomes from normal rat liver is described. The method depends on the swelling of mitochondria when the postnuclear supernatant fraction is incubated with 1 mM Ca2+. The lysosomes can then be separated from the swollen mitochondria by Percoll density gradient centrifugation. The lysosomal fraction obtained by our method was enriched more than 120-fold in terms of the marker enzymes with a yield of 25%. The electron microscopic examination and the measurement of the activities of marker enzymes for various subcellular organelles indicated that our lysosomal preparation was essentially free from contamination by other organelles.

Animals↗