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Biomedical subjects

Y Kitagawa

Publications and source records attributed to Y Kitagawa.

At least 217 records · Page 12Linked to original sources
PubMed1994

Nucleotide sequence of rice dwarf phytoreovirus genome segment 2: completion of sequence analyses of rice dwarf virus.

The complete nucleotide sequence of rice dwarf phytoreovirus genome segment 2 (S2) was determined to be 3,512 nucleotides long with one open reading frame initiating at nucleotide 15 and terminating at nucleotide 3363. The encoded polypeptide was predicted to have 1,116 residues with a relative molecular weight of 123 kD. Comparison of S2 of two isolates showed they had identical lengths and 97 and 98.3% nucleotide and amino acid sequence identities, respectively. A search of the Swiss-Prot data base (R 22.0) failed to find any proteins with significant homology to the S2-encoded protein. Determination of the nucleotide sequence of the S2 has completed the sequence determination of the genome of rice dwarf virus. Homology searches made for proteins encoded by each of the genomic segments showed that the polypeptide encoded by S11 has similarity to histone H1 protein and VP6 of blue tongue virus, indicating it might possess nucleic acid binding properties.

Amino Acid Sequence↗
PubMed1994

Regulated expression of an osteonectin variant in bovine aortic endothelial cells.

Using a mouse SPARC (Secreted Protein, Acidic and Rich in Cysteine) cDNA clone as the probe, three clones were isolated from a cDNA library of bovine aortic endothelial cells (BAEC). Inserted sequences in them were identical with that of bovine bone osteonectin except for the deletion of the TGC codon encoding Cys-193. Northern blot analysis and metabolic radio-labeling of BAEC showed that gene expression and synthesis of the osteonectin variant is stimulated by transforming growth factor (TGF) beta, a basic fibroblast growth factor (FGF), or a naturally occurring splicing variant of hepatocyte growth factor (varHGF).

Animals↗
PubMed1994

Immunocytochemical investigation of rat gamma-glutamyl transpeptidase in chemically-induced hepatocarcinogenesis using monoclonal antibody.

An immunocytochemical study using a monoclonal antibody showed the presence of gamma-glutamyl transpeptidase (gamma-GTP) in the bile duct epithelium of the normal adult rat liver, while a slight immunoreactivity for gamma-GTP could be observed on the membranes of bile canaliculi (the membranes of hepatocytes facing the lumen of bile canaliculi). In hepatocarcinogenesis induced by 3'-methyl-4-dimethylaminoazobenzene, no immunoreactivity was detected in alpha-fetoprotein-positive cholangiolar "oval" cells, though it was detected on the membranes of bile canaliculi. In livers with hyperplastic nodules, gamma-GTP immunoreactivity was observed in clusters, with two different staining patterns. In one pattern, gamma-GTP was present not only on the membranes of bile canaliculi, but also on the membranes facing the Disse's space or the lateral cell surface of hepatocytes. In the other pattern, gamma-GTP immunoreactivity was seen on the membranes of the dilated bile canaliculi. In livers with developing hepatocellular carcinomas, the immunoreactivity was present on the membranes of irregularly dilated bile canaliculi in malignant cells.

Animals↗
PubMed1994

[Recurrence and prognosis in ischemic stroke patients with anticardiolipin antibody in Japan].

Anticardiolipin antibody (aCL) is considered to be one of the contributory factors in the development of cerebral infarction. We compared the recurrence and prognosis of 20 ischemic stroke patients with positive IgG aCL who had no collagen vascular diseases with those in 120 patients with negative IgG aCL. The aCL-positive patients comprised 18 females and 2 males aged 43-79 (mean 64) years and the mean follow-up period was 5.6 years. The aCL-negative patients comprised 82 males and 38 females aged 40-84 (mean 64.2) years and the mean follow-up period was 5.8 years. There was no significant difference in age and mean follow-up period between the two groups. We examined the recurrence rate and the intervals from the onset to the recurrence in both groups. We investigated the relationship between the recurrence of stroke and chronological changes in titer of aCL in patients with positive aCL. We also evaluated the effectiveness of antiplatelet agents for the prevention of recurrent stroke in both groups. A positive aCL level was defined as one which was > 3 standard deviations (S.D.) above the mean level for normal controls. A high titer of aCL was defined as being > 7 S.D. above the normal mean value. Among the 20 patients with positive aCL, recurrence of ischemic stroke occurred in 10 (50%) (cerebral thrombosis in 8 and cerebral embolism in 2) and myocardial infarction developed in 2 patients. As regards the number of ischemic episodes of stroke, recurrence occurred twice in 4 and once in 6 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Production of a monoclonal antibody reactive with poly(A) and its application in the isolation of poly(A)+ RNA.

Hybridoma cells producing antibody reactive with poly(A) were isolated following fusion of spleen cells from a BALB/c mouse immunized with poly(A).poly(dT) and myeloma cells. The antibody was purified from ascitic fluid by the formation of immune complexes with poly(A). The antibody reacted with poly(A) and some homopolymers (poly(dT), poly(I) and poly(dC)) which was most probably due to its reaction with the ribose-phosphate part of the molecules, but not with cellular RNAs and DNA. Poly(A) tailed 5 S rRNA (about 20 nucleotides) and tobacco mosaic virus RNA (1060 nucleotides) were precipitated quantitatively by the antibody. Dot hybridization and in vitro translation confirmed that the RNA precipitated by the antibody from mouse spleen total RNA contained biologically active mRNA.

Antibodies, Monoclonal↗
PubMed1993

Transient gene expression by SV40 promoter characterizes sequential differentiation of embryonal carcinoma F9 cells into primitive and visceral endoderm.

Transient expression of the chloramphenicol acetyltransferase (CAT) gene under the control of simian virus 40 (SV40)y Moloney murine leukemia virus, human T cell leukemia virus, and cytomegalovirus promoters was stimulated by the differentiation of F9 stem cells into primitive endoderm, but repressed again by further differentiation into visceral endoderm. Deletion mutants of the SV40 enhancer showed that a similar set of motifs is critical for CAT expression at all stages of F9 differentiation, but differentiation dependency was observed even in their absence. The stability of transient gene expression under the control of the SV40 promoter was markedly dependent on F9 differentiation. Appreciable expression was detected even in undifferentiated F9 cells immediately after gene transfection, was maximal at 12 h and declined rapidly thereafter. On the other hand, expression in primitive endoderm increased until 72 h. The decline was accelerated again in visceral endoderm. This shift was somewhat specific to the virus promoter since CAT expression in undifferentiated F9 cells under the control of the elongation factor 1 alpha promoter was more stable than for virus promoters tested. Thus, the change in stability of expression is important for differentiation-dependent virus promoter activity.

Animals↗
PubMed1993

The differentiation-dependent inhibition of SV40 early promoter/enhancer activity in 3T3-L1 cells is mediated through promoter and not enhancer sequences.

Using a plasmid bearing chloramphenicol acetyltransferase (CAT) gene controlled by Simian virus 40 (SV40) early promoter/enhancer complex (pA0cat), we analyzed functional enhancer motifs in 3T3-L1 fibroblast and adipocyte cells. Deletion mutant series of pA0 at the enhancer complex showed that gene expression both in fibroblast and adipocyte cells was dependent on a similar set of enhancer motifs. When pA0 was introduced into 3T3-L1 fibroblasts and the cells were induced to differentiate into adipocytes, CAT activity expressed in fibroblasts was suppressed. Experiments with the deletion mutants at the enhancer complex showed that the suppression was not related to any enhancer motif, and CAT activity was observed with a plasmid having only the promoter sequence. When pA0cat was co-transfected with excess of promoter sequence, the suppression in adipocytes was counteracted. This suggested that negative trans-acting factors of the promoter sequence were responsible for the suppression in adipocytes.

3T3 Cells↗
PubMed1993

Protective effects of sesamin against liver damage caused by alcohol or carbon tetrachloride in rodents.

The effects of sesamin, a potent inhibitor of delta 5-desaturase in polyunsaturated fatty acid biosynthesis, on the fatty acid compositions of tissue lipids and liver functions were examined in rodents. When a mixture of sesamin and episesamin (51.1:48.2, w/w) was given to rats at a dietary level of 0.5% for 13 days, the proportions of dihomo-gamma-linolenic acid significantly increased not only in the liver but also in plasma and hemocytes, suggesting an interference with delta 5-desaturation by these lignans. The sesamin preparation at the dietary level of 1% improved changes in various blood parameters of the mouse, such as aspartate aminotransferase and alanine aminotransferase activities, and the concentrations of total cholesterol, triglyceride and total bilirubin, caused by continuous inhalation of ethanol. In addition, sesamin showed a significant protective effect against the accumulation of fat droplets and vacuolar degeneration in the mouse liver, as confirmed on histological examination. Sesamin, at the level of 100 mg/kg body weight, also tended to prevent liver lipid accumulation by carbon tetrachloride in mice. These results indicate that sesamin and a related lignan compound have an ability to improve liver function.

Administration, Inhalation↗
PubMed1993

[Clinicopathological study of Ewing's sarcoma and primitive neuroectodermal tumor].

A comparative study concerning the histogenesis of Ewing's sarcoma and its relationship with peripheral primitive neuroectodermal tumor (PNET) was undertaken using histological, immunohistochemical and ultrastructural techniques. The cases studied included 22 Ewing's sarcomas, 17 (ganglio) neuroblastomas, 3 peripheral PNETs, 1 peripheral neuroblastoma, 1 Askin's tumor and a case in which it was difficult to distinguish between Ewing's sarcoma and neuroblastoma. Almost all the cases of Ewing's sarcoma showed neural differentiations. Immunohistochemical study using antibodies for neuron-specific enolase, protein gene product 9.5, Leu 7 and neurofilament (200 kD) was most useful for examining the neural differentiation of these tumors. These results suggest that Ewing's sarcoma is in a broad sense one of such peripheral PNETs as (ganglio) neuroblastoma, peripheral neuroblastoma and Askin's tumor.

Adolescent↗
PubMed1992

Site-specific and random fragmentation of Cu,Zn-superoxide dismutase by glycation reaction. Implication of reactive oxygen species.

Site-specific and random fragmentation of human Cu,Zn-superoxide dismutase (Cu,Zn-SOD) was observed following the glycation reaction (the early stage of the Maillard reaction). The fragmentation proceeded in two steps. In the first step, Cu,Zn-SOD was cleaved at a peptide bond between Pro62 and His63, as judged by amino acid analysis and sequencing of fragment peptides, yielding a large (15 kDa) and a small (5 kDa) fragment. In the second step, random fragmentation occurred. The ESR spectrum of the glycated Cu,Zn-SOD suggested that reactive oxygen species was implicated in the both steps of fragmentation. The same fragmentations were seen upon exposure of the enzyme to an H2O2 bolus. Catalase completely blocked both steps of the fragmentation process, whereas EDTA blocked only the second step. Incubation with glucose resulted in a time-dependent release of Cu2+ from the Cu,Zn-SOD molecule. The released Cu2+ then likely participated in a Fenton's type of reaction to produce hydroxyl radical, which may cause the nonspecific fragmentation. Evidence that EDTA abolished only the second step of fragmentation induced by an H2O2 bolus supports this mechanism. This is the first report that a site-specific fragmentation of a protein is caused by reactive oxygen species formed by the Maillard reaction.

Amino Acid Sequence↗
PubMed1992

Molecular analysis of rice dwarf phytoreovirus segment S1: interviral homology of the putative RNA-dependent RNA polymerase between plant- and animal-infecting reoviruses.

We have determined the complete nucleotide sequence of the largest segment S1 of rice dwarf phytoreovirus (RDV), a member of the family Reoviridae. S1 is 4423 nucleotides long with a segment-specific inverted repeat located adjacent to the conserved termini (5'GGCAAA---UGAU3'). A major open reading frame (bases 36 to 4367) on the S1 plus strand, which is preceded by a minicistron (bases 6 to 29), encodes the polypeptide (P1) consisting of 1444 amino acids with a M(r) of 164, 142. The sense-strand transcript derived from the full-length S1 cDNA, the minicistron of which was abolished, directed the synthesis of a polypeptide of 170 kDa in addition to smaller polypeptides in wheat germ extracts, and the 170-kDa product comigrated with the minor core protein in SDS-polyacrylamide gel. Thus, P1 is assumed to be localized in the viral core particle. The consensus sequence element conserved in RNA-dependent RNA polymerase is observed in the P1 amino acid sequence predicted from the nucleotide sequence. Based on the dendrogram established from the sequence alignment around the polymerase module region, and sequence identity within the alignment, P1 of plant-infecting RDV was evolutionarily compared with VP1, lambda 3, and VP1 of three other animal-infecting members of the family, rota-, reo-, and bluetongue viruses. Consequently, RDV S1 was shown to be more closely related to the rotavirus gene segment 1, in terms of molecular evolution, than the animal-infecting members are to one another.

Amino Acid Sequence↗
PubMed1992

[Study of an outbreak of itai-itai disease].

We studied an outbreak of itai-itai disease in the Jinzu River basin, in Toyama, Japan. One hundred and fifty females recognized as itai-itai disease patients till by 1990 were studied for the ages and years of onset and residence in the cadmium-polluted area. 1. Cases were recognized from as early as 1929, increased gradually to the peak of 1955-1959 and rapidly decreased up to the 1970s. 2. It was found that the later the patients was born, the younger the age of onset, though there was no difference of ages of onset between the cases born in the 1910s and the cases born from 1920. 3. The onset of itai-itai disease was most frequently seen at 50-59 years of residence in the cadmium-polluted area. It was found that the later a person started to inhabit the cadmium-polluted area, the shorter the period of residence in the cadmium-polluted area up to onset of itai-itai disease. 4. Comparing the patients who inhabited the cadmium-polluted area from birth and those who had moved there from non-polluted areas, the age of onset was higher in the latter, but there were no significant differences in the period of residence up to onset. From these findings, it appeared that itai-itai disease was not caused by aging, but by cadmium exposure starting from the 1910s.

Cadmium Poisoning↗