[Interstitial nephritis associated with neoplasms].
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Humans↗
Biomedical subjects
N Kato
Publications and source records attributed to N Kato.
[Two operative cases of quadricuspid aortic valve].
We report two cases of rare congenital anomaly of quadricuspid aortic valve. Case 1, an 81-year-old man was operated on because of aortic regurgitation without diagnosis of a quadricuspid aortic valve. He underwent aortic valve replacement with a 21 mm Hancock-II successfully. Case 2, a 40-year-old woman suffering from aortic regurgitation was diagnosed as quadricuspid aortic valve, before surgery using echocardiography and aortography. She underwent aortic valve replacement with a 21 mm H-P St. Jude Medical prosthesis successfully. Both cases were regarded as type c (2 equal larger cusps, 2 equal smaller cusps) by Hurwitz's classification. Thirty cases of quadricuspid aortic valve are reviewed in the Japanese literature including our two cases. All cases underwent aortic valve replacement because of aortic regurgitation. In 19 cases, it was possible to diagnose that those valves were quadricuspid before surgery, using echocardiography and aortography. In conclusion, it is necessary to take quadricuspid aortic valve into consideration in the case of aortic regurgitation.
Adult↗
[Microbiological tests for determination of specific microbes--partial anaerobic bacteria].
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Bacteria, Anaerobic↗
[Hepatitis C virus as a causative agent of carcinogenesis--recent trends for study].
Hepatitis C virus (HCV) infection causes chronic hepatitis, cirrhosis and hepatocellular carcinoma. However, the mechanism of carcinogenesis by HCV is poorly understood. In this paper, the recent virological and molecular biological studies of HCV published in after 1996 were summarized including the past reported data. Major topics of the study are the biological functions of HCV proteins and the interaction between HCV proteins and cellular proteins. HCV replication and proliferation systems using human cultured cells were also described. The possible role of HCV for development of hepatocellular carcinoma is discussed.
Carcinoma, Hepatocellular↗
[Significance of residual renal functions of patients with end-stage renal failure undergoing continuous ambulatory peritoneal dialysis].
It is generally accepted that residual renal function remains well-preserved longer with CAPD than with hemodialysis. However, consideration and impact of the contributory effects of residual renal function on the adequacy of renal replacement therapy has not been well defined. In this report, creatinine clearance (Ccr), Kt/V, normalized protein catabolic rate (nPCR) and urinary excretion of uremic solutes were studied in 26 stable CAPD patients with a four-bag exchange. Weekly Ccr, weekly Kt/V and nPCR were 62.3 +/- 20.2 l/week/1.73 m2, 1.77 +/- 0.35, and 0.90 +/- 0.13 g/kg/day, respectively. These parameters correlated significantly with the daily urine volume. The weekly Ccr and Kt/V of anuric patients seemed to be inadequate. Urinary excretion of urea nitrogen, Cr, Na, Cl, Pi and beta 2-microglobulin (beta 2-MG) were dependent upon the daily urine volume. Significant phosphorus and beta 2-MG excretion seemed to have an effect on the prevention of bone and joint complications, because serum iPTH and beta 2-MG levels increased after the patients fell into an anuric state. It was suggested from this study that CAPD should be started before the patient loses residual renal function because four bag exchange as the standard CAPD prescription might not be adequate once the patient loses urine excretion.
Adult↗
Primary structures of fungal fructosyl amino acid oxidases and their application to the measurement of glycated proteins.
Fructosyl amino acid oxidase (FAOD), which is active toward model compounds of the glycated proteins in blood, N epsilon-fructosyl N sigma-Z-lysine and N-fructosyl valine, was purified to homogeneity from Aspergillus terreus GP1. Though the enzyme did not use glycated proteins directly as its substrate, it used glycated human serum albumin (HSA) when HSA was treated with a protease. Linear relationships between both the concentration and the increase in absorbance and the glycation rate of glycated HSA and the increase in absorbance were observed. cDNAs coding for FAODs were cloned from cDNA libraries of A. terreus GP1 and Penicillium janthinellum AKU 3413. The coding region for both fungal FAODs consisted of 1314 bp encoding 437 amino acids. The sequence of a dinucleotide-binding motif, GXGXXG, was in the deduced N-terminal region and a similar sequence to that the active site of bacterial sarcosine oxidases was found near the C-terminal region of FAOD. The of C-terminal tripeptides SKL and AKL of FAODs from A. terreus and P. janthinellum, respectively, represent typical peroxisomal-targeting signals. Finally, FAOD protein was produced in Escherichia coli transformants in an active form, and at the same level as in the original fungi.
Amino Acid Oxidoreductases↗
A transforming growth factor beta type II receptor gene mutation common in sporadic cecum cancer with microsatellite instability.
Mismatch repair genes are the responsible genes for hereditary non-polyposis colon cancer, and mutation of these genes causes replication error (RER). In several RER-positive colon cancer cell lines, mutations of repetitive sequences of transforming growth factor beta (TGF-beta) type II receptor (RII) gene have been reported. Since TGF-beta inhibits cell proliferation, loss of response to TGF-beta is an important tumor progression step. In this study, the relationship between RER status and mutation of the RII gene was analyzed in 112 cases of various types of sporadic gastrointestinal and hepatobiliary cancer (41 with gastric, 49 with colorectal, 5 with gallbladder, and 17 with hepatic cancers). RER was found in 17 cases (4 with gastric, 12 with colorectal, and 1 with gallbladder cancer), and 10 of those (3 with gastric and 7 with colorectal cancer) showed mutations of the RII gene. Of interest was that in all seven cases with colorectal cancer, tumors were located at the cecum. These data indicate that mutation of the RII gene, presumably caused by abnormality of repair gene, play an important role in carcinogenesis of sporadic gastrointestinal cancer, especially at the cecum.
Aged↗
Long-term human T-cell culture system supporting hepatitis C virus replication.
We recently found that human T-cell leukemia virus type I-infected cloned MT-2C cells could support the replication of hepatitis C virus (HCV) up to 30 days postinoculation (p.i.). To obtain a more persistent HCV replication system using MT-2C cells, we examined the effect of various culture conditions after virus inoculation. We found that persistent HCV infection (at least 80 days) could be reproducibly achieved by reducing the temperature from 37 degrees C to 32 degrees C. Under this culture condition, HCV RNA could be detected in the cells up to 198 days p.i. Sequence analysis of HCV hypervariable region 1 revealed that certain HCV species became predominant during the culture period. We also demonstrated that virus transmission by the cell-free mode could be successfully repeated at least 4 times at 32 degrees C as opposed to only twice at 37 degrees C. This HCV-infected culture system will be useful for the various biological studies, including investigations into the mechanisms of HCV replication and multiplication.
Amino Acid Sequence↗
Effects of the low-molecular-weight GTP-binding protein RhoA on calcium waves in xenopus oocytes.
In normal Xenopus oocytes, injection of high concentrations of inositol-1,4,5-trisposphate (IP3) always elicited a Ca2+ wave, which propagated from the injection site toward the opposite side of the oocyte. In oocytes injected with C3 toxin, a specific blocker of RhoA, a similar Ca2+ wave was still observed, but propagation of the wave appeared to be retarded compared with normal controls. This apparent retardation seemed to be due to a slower decrease of normally increased Ca2+ rather than to a slower increase of Ca2+. It is suggested that RhoA may play a role in Ca2+ reuptake mechanisms.
Animals↗
Attenuation of Mg2(+)-block of synaptic N-methyl-D-aspartate receptors in the visual cortex of rats raised under optic nerve blockade.
It has been known that the sensitive period for ocular dominance column plasticity is prolonged in animals raised under light deprivation. We tested whether this prolongation is related to a developmental change in Mg2+ block of N-methyl-D-aspartate (NMDA) receptors. Synaptic potentials were recorded intracellularly from visual cortex slices of rats whose optic nerves were blocked bilaterally by tetrodotoxin injected into the eyes for 2-4 weeks of age. In cells from normal rats, the amplitude of NMDA receptor-mediated synaptic potentials became smaller at more negative membrane potentials, and larger at more positive potentials, even at 0.1 mM [Mg2+]o. In cells from tetrodotoxin-treated rats, the voltage-dependence was significantly weaker than in cells from normal rats at 0.1 mM [Mg2+]o. Thus, Mg(2+)-block of synaptic NMDA receptors in the visual cortex may be regulated by optic nerve activity, and may thereby control the sensitivity to synaptic plasticity in an activity-dependent manner.
6-Cyano-7-nitroquinoxaline-2,3-dione↗
High-level secretion of fungal glucoamylase using the Candida boidinii gene expression system.
The methylotrophic yeast, Canadida boidinii, was investigated as an expression host for secretory enzyme production. The cDNA of Rhizopus oryzae glucoamylase was placed under the C. boidinii alcohol oxidase (AODl) promoter. A transformant integrated with a single-copy expression cassette to the chromosome produced glucoamylase into the medium to a high amount when the cells were grown on methanol or methanol plus glycerol as (a) carbon source(s). The transformant C. boidinii cells were grown up to ca. 95 g dry cell weight/liter medium, and the concentration of glucoamylase in the medium reached 3.4 g/liter. This showed that the signal sequence from Rhizopus glucoamylase functioned very efficiently in C. boidinii. Next, secreted glucoamylase from C. boidinii was purified and compared with the enzyme produced in S. cerevisiae. The enzyme produced in C. boidinii was found to have higher molecular weight than that produced in S. cerevisiae, which was due to the difference of the N-linked glycosylated sugar structure of the produced proteins.
Alcohol Oxidoreductases↗
Comparison of hypervariable regions (HVR1 and HVR2) in positive- and negative-stranded hepatitis C virus RNA in cancerous and non-cancerous liver tissue, peripheral blood mononuclear cells and serum from a patient with hepatocellular carcinoma.
Hepatitis C virus (HCV) infection is associated with a wide spectrum of liver diseases including cirrhosis and hepatocellular carcinoma (HCC). Although the biological relation between the virus and cirrhosis or HCC is unclear, such variable pathogenicity may be related to the genetic heterogeneity of HCV. Genetic variability of HCV was assessed by determining the nucleotide sequence corresponding to the hypervariable regions (HVR1 and HVR2) of the putative envelope protein (E2/NS1) in positive- and negative-stranded HCV RNA from the cancerous and surrounding non-cancerous liver tissue, peripheral blood mononuclear cells and serum of a patient with HCC. Nineteen distinct HVR1 amino acid sequences (deduced from the nucleotide sequences) were obtained from the patient and could be classified into 5 groups on the basis of the site and time of detection. Some viral isolates with the same HVR1 sequence were shown to replicate in both cancerous and non-cancerous liver tissue, whereas others replicated in HCC tissue only.
Amino Acid Sequence↗
Effect of Clostridium difficile toxin B on IgE receptor-mediated signal transduction in rat basophilic leukemia cells: inhibition of phospholipase D activation.
Antigen (Ag)-stimulated phospholipase D (PLD) activation and secretion were almost abolished by pretreatment of rat basophilic leukemia (RBL)-2H3 cells for 4 h with 5 ng/ml Clostridium difficile Toxin B which is known to inhibit Rho family proteins (Rho, Cdc42, Rac). The concentration-dependent inhibition of PLD activation was well correlated with the level of glucosylation of Rho family proteins. In streptolysin O-permeabilized RBL cells, Toxin B suppressed [3H] phosphatidylbutanol (PBut) formation in response to guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) and phorbol 12-myristate 13-acetate (PMA) by 67 and 43%, respectively. The synergistic PLD activation by GTP gamma S and PMA was also reduced by Toxin B by 67%. These results suggest that the IgE receptor-coupled PLD activation is largely mediated by Rho proteins.
Animals↗
Suppressor mutations in alpha-subunit of RNA polymerase for a mutant of the positive regulator, OmpR, in Escherichia coli.
The OmpR protein is a positive regulator specific for the Escherichia coli ompF and ompC genes. This protein functions in a phosphorylation-dependent manner through a presumed interaction with RNA polymerase. We previously isolated OmpR mutants which were suggested to be defective in transcription activation, but not in DNA binding (the so-called positive control (PC) mutant). In this study we isolated mutants of the alpha-subunit of RNA polymerase which can suppress one of the putative PC mutants of OmpR. A crucial amino acid substitution was identified as [V264G] in the alpha-subunit, which is located in the helix H1 of the C-terminal domain, which has been claimed, based on mutational and structural analyses, to be involved in the interaction with other positive regulators including the well-characterized cAMP receptor protein.
Bacterial Outer Membrane Proteins↗
Adenomyoepithelioma of the Breast: A Case Reprot and a Review of Literature.
A 74-year-old woman complained of a small nodule in the outer lower quadrant of her left breast. On physical examination, a 0.9 x 0.8 cm, round-shaped and firmly elastic nodule was palpated. Excisional biopsy was performed. Histologically, the tumor was separated into, with a bicellular pattern, containing both numerous glandular structures and numerous spindle-shaped cells. Immunohistochemical staining for EMA and cytokeratin showed strongly positive immunoreactivity for epithelial cells. Staining for &aipha;-SMA showed strongly positive immunoreactivity for myoepithelial components. Staining for keratin and S-100 protein showed weakly positive immunoreactivity for myoepithelial cells. Microscopically, the tumor was diagnosed as adenomyoepithelioma of the breast. Immunohistochemical examination is needed to distinguish epithelial cell proliferation from myoepithelial cell proliferation. Immunohistochemical examination using antibodies against EMA, alpha-SMA, Keratin, cytokeratin and S-100 protein, is indispensable.
Journal Article↗
Nitric oxide synthase-containing neurons in the hippocampus are preserved in trimethyltin intoxication.
We studied the effects of trimethyltin (TMT) (9 mg/kg, p.o.) on the nitric oxide synthase (NOS)-containing neurons in the rat hippocampus by NADPH-diaphorase histochemistry and a biochemical assay of NOS activity. TMT exposure caused the typical behavioral changes and a loss of the CA3/4 pyramidal cells, which were NADPH diaphorase-negative. The scattered interneurons and the CA1 pyramidal cells, which were NADPH diaphorase-positive, were spared. Hippocampal NOS activity showed no reduction in the TMT-treated rats compared with the controls. These results provide evidence of the preservation of the NOS-containing neurons in TMT intoxication.
Animals↗
Overproduction and characterization of the StsI restriction endonuclease.
The StsI restriction endonuclease (R-StsI), a class-IIS restriction endonuclease, found in Streptococcus sanguis 54, is a heteroschizomer of R-FokI, which recognizes 5'-GGATG-3'. To overproduce R-StsI in Escherichia coli, the coding region of R-StsI was joined to the tac promoter of an expression vector, pKK223-3. By introduction of the plasmid into E. coli UT481 cells expressing the fokIM gene, R-StsI activity was overproduced, from which R-StsI was purified homogeneously. We compared the properties of R-StsI with those of R-FokI. The optimum reaction conditions for R-StsI were quite different fron those for R-FokI. R-StsI is an acidic protein (pI 6.3). Anti-R-StsI serum did not cross-react with R-FokI, indicating three-dimensional structural dissimilarity. The domain structure of R-StsI was elucidated by digestion with trypsin. In the presence of substrate DNA, R-StsI was digested to yield 45-kDa N-terminal and 23-kDa C-terminal fragments. The amino-acid sequences around the trypsin cleavage sites of R-StsI and R-FokI were quite homologous.
Amino Acid Sequence↗
Cloning and sequence analysis of the gene encoding 3-hexulose-6-phosphate synthase from the methylotrophic bacterium, Methylomonas aminofaciens 77a, and its expression in Escherichia coli.
A DNA fragment of 550 bp was specifically amplified by PCR with primers based on the N-terminal sequence of the purified 3-hexulose-6-phosphate synthase from Methylomonas aminofaciens 77a and on that of a lysyl endopeptidase-derived peptide. Using this PCR product as a probe, a gene coding for 3-hexulose-6-phosphate synthase in M. aminofaciens 77a chromosomal DNA was cloned in Escherichia coli JM109. Sequencing analysis revealed that the gene encoding 3-hexulose-6-phosphate synthase contained a 624-bp open reading frame, encoding a protein composed of 208 amino acid residues with a calculated relative molecular mass of 21,224.
Aldehyde-Lyases↗