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Biomedical subjects

A Kato

Publications and source records attributed to A Kato.

At least 361 records · Page 20Linked to original sources
PubMed1996

Accelerated evolution in inhibitor domains of porcine elafin family members.

Through the analysis of the porcine gene encoding the elastase inhibitor elafin, we demonstrated that there are at least three closely related members of the elafin family, and their genes have arisen by accelerated evolution. A porcine genomic DNA library was screened with a previously cloned human elafin cDNA probe, and several positive clones were obtained that can be distinguished by a combination of restriction enzymes. Sequence analysis of these clones revealed the presence of three homologous members whose genes, all consisting of three exons and two introns, are almost identical except the exon 2 sequences encoding the inhibitor domain called "WAP motif"; the intron sequences are related to each other with sequence similarities of 93-98%, whereas the exon 2 sequences exhibited only 60-77% similarities among the three members. The extreme divergence in the exon 2 sequences compared to the highly conserved intron sequences may be generated by accelerated mutations confined in a short stretch of the genes following recent duplication events of a single ancestral gene. An RNase protection assay indicated that the messages of the elafin family members are abundantly expressed in the trachea and intestine, suggesting that the most likely selective forces for the accelerated evolution are extrinsic proteinases produced by invasive microorganisms.

Amino Acid Sequence↗
PubMed1996

Increase in activin beta A mRNA in rat hippocampus during long-term potentiation.

We have used mRNA differential display to isolate genes that are induced by neural activity in rat hippocampus. One of these encodes activin beta A subunit. Convulsive seizure caused by kainate significantly induced the expression of activin beta A mRNA. Furthermore high frequency stimulation (HFS) of perforant pathway, which produced a persistent long-term potentiation (LTP) (>10 h), caused a marked increase at 3 h in the level of activin beta A mRNA at the dentate gyrus of urethane-anesthetized rat. The increase was NMDA receptor-dependent. By contrast the level of inhibin alpha mRNA was not changed following the induction of LTP. THe results suggest a role for activin in maintenance of neural plasticity in the adult brain.

Activins↗
PubMed1996

Postcolumn co-immobilized leucine dehydrogenase-NADH oxidase reactor for the determination of branched-chain amino acids by high-performance liquid chromatography with chemiluminescence detection.

A liquid chromatographic system with a co-immobilized leucine dehydrogenase-NADH oxidase reactor is described for the determination of branched-chain amino acids such as I-leucine, I-isoleucine and I-valine. The enzymes were simultaneously immobilized on tresylate-containing poly(vinyl alcohol) beads. The separation was achieved by means of an ODS column with elution with phosphate buffer (pH 7.5). The hydrogen peroxide produced was detected chemiluminometrically via a luminol-hexacyanoferrate(III) reaction. The system gave a linear response from 0.3 to 300 mu M for each amino acid and the detection limit was 0.1 mu M.

Amino Acid Oxidoreductases↗
PubMed1996

Epstein-Barr virus infection and associated products (LMP, EBNA2, vIL-10) in nodal non-Hodgkin's lymphoma of human immunodeficiency virus-negative Japanese.

Sixty cases of B-cell nodal non-Hodgkin's malignant lymphoma (B-ML), and 46 cases of T-cell nodal lymphoma (T-ML) were surveyed for Epstein-Barr virus (EBV) genomes, RNA, and associated proteins. We used a Southern blot analysis, polymerase chain reaction (PCR), and EBV-encoded small RNA-1 (EBER-1) in situ hybridization to investigate the presence of EBV. We performed an immunohistochemical study on EBV-related oncoproteins, such as EBV-determined nuclear antigen-2 (EBNA-2), latent membrane protein (LMP), and viral interleukin-10 (vIL-10). In addition, we also analyzed the terminal repetitive sequence of EBV (EBV-TR) to investigate the EBV-infected cell clonality. Non-Hodgkin's lymphomas were grouped into three types by number of EBV-infected cells: I) almost all lymphoma cells showed an EBV presence; II) some scattered lymphoma cells showed an EBV presence; and III) only a few cells showed such a presence, which was probably due to a latent EBV infection. In 25 of 60 B-MLs, EBV-infected cells were found; 7 were type I, 1 was type II, and 17 were type III. In 27 of 46 T-MLs, EBV-infected cells were found; no cases were type I, 5 cases were type II, and 22 cases were type III. Seven B-MLs and 3 T cell lymphomas showed clonal TR bands. Expression of EBNA-2 was found in only three B-MLs, whereas LMP was seen in four B-MLs and six T-MLs. All EBNA-2/LMP-positive cases showed an EBV presence. In B-MLs, expression of EBNA-2 and LMP was detected in almost all lymphoma cells; in T-MLs, however, LMP was found in only a small portion of the lymphoma cells. Expression of IL-10 was closely associated with LMP. In summary, it was thus speculated that EBV infection was associated with the various states of lymphomagenesis.

Antigens, Viral↗
PubMed1996

Classical Hodgkin and Reed-Sternberg cells demonstrate a non-clonal immature B lymphoid lineage: evidence from a single cell assay and in situ hybridization.

Hodgkin and Reed-Sternberg (H & RS) cells are generally considered to be the neoplastic cells of Hodgkin's disease (HD), however such cells are only found in a minority of the lesions. Recently in a few studies on HD, the clonality of H & RS cells was examined, using a single-cell polymerase chain reaction (PCR) examination. To clarify the lineage and clonality of H & RS cells, we performed single cell PCR and in situ hybridization (ISH), and nine cases of classical HD were thus studied. By ISH, the immunoglobulin J chain, and the kappa and lambda light chain were rarely expressed in the H & RS cells, however, no T-cell markers could be detected. The expression of the recombination activating genes (RAG-1, 2) could be determined in the H & RS cells. We isolated CD30+ H & RS cells, CD3 + T cells and CD20 + B cells from suspended materials using a mechanical sorter. We performed single cell PCR in a sorted individual cell, to amplify the complementarity determining region of the Ig heavy chain (IgH) gene and T-cell receptor gamma chain (TCR gamma) gene. In all cases, TCR gamma could be frequently amplified in the T cells, but was only rarely amplified in the H & RS and B cells. In contrast, the IgH was frequently amplified in the H & RS and B cells, but not in the T cells. In addition, the PCR production of the H & RS cells all showed different lengths. The results therefore support the polyclonal nature and immature B lymphoid cell origin of H & RS cells.

B-Lymphocyte Subsets↗
PubMed1996

cDNA cloning and expression of a gene for 3-ketoacyl-CoA thiolase in pumpkin cotyledons.

A cDNA clone for 3-ketoacyl-CoA thiolase (EC 2.3.1.16) was isolated from a lambda gt11 cDNA library constructed from the poly(A)+ RNA of etiolated pumpkin cotyledons. The cDNA insert contained 1682 nucleotides and encoded 461 amino acid residues. A study of the expression in vitro of the cDNA and analysis of the amino-terminal sequence of the protein indicated that pumpkin thiolase is synthesized as a precursor which has a cleavable amino-terminal presequence of 33 amino acids. The amino-terminal presequence was highly homologous to typical amino-terminal signals that target proteins to microbodies. Immunoblot analysis showed that the amount of thiolase increased markedly during germination but decreased dramatically during the light-inducible transition of microbodies from glyoxysomes to leaf peroxisomes. By contrast, the amount of mRNA increased temporarily during the early stage of germination. In senescing cotyledons, the levels of the thiolase mRNA and protein increased again with the reverse transition of microbodies from leaf peroxisomes to glyoxysomes, but the pattern of accumulation of the protein was slightly different from that of malate synthase. These results indicate that expression of the thiolase is regulated in a similar manner to that of other glyoxysomal enzymes, such as malate synthase and citrate synthase, during seed germination and post-germination growth. By contrast, during senescence, expression of the thiolase is regulated in a different manner from that of other glyoxysomal enzymes.

Acetyl-CoA C-Acyltransferase↗
PubMed1996

Characterization of common cis-regulatory elements responsible for the endosperm-specific expression of members of the rice glutelin multigene family.

Glutelin is the most abundant storage protein in rice, which is expressed specifically in the endosperm of maturing seed. Glutelin is encoded by about 10 genes per haploid genome, which are clearly divided into two subfamilies (GluA and GluB). Most of them are coordinately expressed during seed maturation in spite of the remarkable divergence in the 5'-flanking regions between members of two subfamilies. In order to identify the common regulatory mechanisms responsible for the endosperm-specific expression, various cis-regulatory elements in the 5'-flanking region of the glutelin GluB-1 gene were characterized by studying the expression of chimeric genes that consisted of the sequentially deleted or mutagenized promoter and a beta-glucuronidase (GUS) reporter gene in transgenic tobacco seeds. The essential cis-regulatory elements governing the spatially and temporally specific expression of the glutelin gene expression were located within the first 245 bp of the promoter region of the GluB-1 gene from the site of initiation of transcription. The AACA motif between positions -73 and -61 common to all the six genes for glutelin sequenced to date and is repeated between positions -212 and -200 is implicated in the seed-specific expression. The GCN4 motif between positions -165 and -158 and between positions -96 and -92 that is conserved at homologous sites in all the members of glutelin gene family is also involved in the seed-specific regulation. However, both are required for the high level of seed-specific expression, because deletion of the region containing one set of both elements or substitution mutation of the AACA or GCN4 motif substantially reduced the activity. As a whole, our results suggest the combinatorial interaction of the elements in regulation of the glutelin gene expression.

Base Sequence↗
PubMed1996

A case of ovarian carcinoma with production of granulocyte colony-stimulating factor.

A 60-year-old female with ovarian carcinoma showed marked leucocytosis. After exploratory laparotomy she had received carboplatin-based chemotherapy, but she died of respiratory failure. In this case the immunohistochemical examination of the tumour cells showed partial-positive staining for anti-G-CSF monoclonal antibody in addition to the elevation of the serum G-CSF concentration. This case is the first report of an ovarian carcinoma producing G-CSF.

Adenocarcinoma↗
PubMed1996

Initiation of Sendai virus multiplication from transfected cDNA or RNA with negative or positive sense.

BACKGROUND: The mononegavirus superfamily (Mononegavirales) comprises three families, Rhabdoviridae, Paramyxoviridae and Filoviridae. These viruses possess a single stranded negative sense RNA as the genome. Recent success in the recovery of infectious virus from a transfected cDNA of mononegaviruses including Sendai virus, a prototypic paramyxovirus, is opening the possibility of their genetic engineering. However, infectious viruses have been recovered only by initiating the infectious cycle with cDNA directing the synthesis of antigenomic positive sense (+)RNA. Starting with genomic negative sense (-)RNA has been unsuccessful. Furthermore, the recovery efficiency has often been extremely low. RESULTS: We describe here an analogous system that allows recovery of Sendai virus at a high rate, from cells in which the transfected cDNA and plasmids to support the synthesis of viral nucleocapsid protein and RNA polymerases are coexpressed by vaccinia virus-driven bacteriophage T7 polymerase. Our system was able to recover the virus from cDNA directing not only (+)RNA but also (-)RNA. Moreover, using this system, we succeeded in recovery of the virus by transfection of in vitro synthesized (+)RNA or (-)RNA. This improved virus recovery appeared to be accomplished by supplying the supporting plasmids at an optimal ratio and by minimizing the cytopathic effect of the vaccinia virus by specific inhibitors. In addition, it was probably critical that our cDNAs were constructed to generate viral authentic RNAs without adding T7 promoter-specific nucleotides to the 5' ends. An immediate application of the system was demonstrated by the creation of a candidate vaccine strain with a predetermined attenuating mutation in the cleavage-activation site of the viral fusion glycoprotein. CONCLUSION: We have established methods which greatly improve the recovery of Sendai virus from cDNA. There is essentially no absolute obstacle to recovery of the virus from the (-)RNA template. Even the complete full length RNA chain in the naked form appears to be properly encapsidated to become a functional template.

Amino Acid Sequence↗
PubMed1996

Transport of chimeric proteins that contain a carboxy-terminal targeting signal into plant microbodies.

Malate synthase is a glyoxysome-specific enzyme. The carboxy-terminal tripeptide of the enzyme is Ser-Arg-Leu (SRL), which is known to function as a peroxisomal targeting signal in mammalian cells. To analyze the function of the carboxy-terminal amino acids of pumpkin malate synthase in plant cells, a chimeric gene was constructed that encoded a fusion protein which consisted of beta-glucuronidase and the carboxyl terminus of the enzyme. The fusion protein was expressed and accumulated in transgenic Arabidopsis that had been transformed with the chimeric gene. Immunocytochemical analysis of the transgenic plants revealed that the carboxy-terminal five amino acids of pumpkin malate synthase were sufficient for transport of the fusion protein into glyoxysomes in etiolated cotyledons, into leaf peroxisomes in green cotyledons and in mature leaves, and into unspecialized microbodies in roots, although the fusion protein was no longer transported into microbodies when SRL at the carboxyl terminus was deleted. Transport of proteins into glyoxysomes and leaf peroxisomes was also observed when the carboxy-terminal amino acids of the fusion protein were changed from SRL to SKL, SRM, ARL or PRL. The results suggest that tripeptides with S, A or P at the -3 position, K or R at the -2 position, and L or M at the carboxyl terminal position can function as a targeting signal for three kinds of plant microbody.

Amino Acid Sequence↗
PubMed1996

Effect of jinkoh-eremol and agarospirol from agarwood on the central nervous system in mice.

Agarwood (Jinkoh in Japanese), one of the Oriental medicines, is used as a sedative. The benzene extract of this medicine showed a prolonged effect on the hexobarbital-induced sleeping time, and hypothermic effects in terms of rectal temperature, a suppressive effect on acetic acid-writhing, and a reduction of the spontaneous motility in mice. By repeated fractionation, oral administration in mice, and pharmacological screening, the active principles, jinkoh-eremol and agarospirol, were obtained from the benzene extract. They also gave positive effects on the central nervous system by peritoneal and intracerebroventricular administration. They decreased both methamphetamine- and apomorphine-induced spontaneous motility. The level of homovanillic acid in the brain was increased by them, while the levels of monoamines and other metabolites were unchanged. Similar results were seen in chlorpromazine-administered mice. Therefore, jinkoh-eremol and agarospirol can be considered to be neuroleptic.

Animals↗
PubMed1996

Hypoglycemic effect of the rhizomes of Polygala senega in normal and diabetic mice and its main component, the triterpenoid glycoside senegin-II.

The hypoglycemic effect of the rhizomes of Polygala senega L. var. latifolia Torrey et Gray (Polygalaceae) was investigated in normal and KK-Ay mice, one of the model animals of non-insulin dependent diabetes mellitus (NIDDM). The n-butanol extract of senega rhizomes (SN) (5 mg/kg) reduced the blood glucose of normal mice from 191 +/- 3 to 120 +/- 3 mg/dl 4 hours after intraperitoneal administration (P < 0.001), and also showed a significant decrease in the glucose level of KK-Ay mice from 469 +/- 38 to 244 +/- 14 mg/dl under similar conditions (P < 0.001). But streptozotocin-induced diabetic mice did not experience a change in the blood glucose after administration of SN. We propose that the hypoglycemic effect of SN occurs without altering the insulin concentration. Moreover, SN needs the presence of insulin in order to act. In addition, one of the active components of the hypoglycemic effect was identified as a triterpenoid glycoside, senegin-II.

Animals↗
PubMed1996

Targeting and processing of a chimeric protein with the N-terminal presequence of the precursor to glyoxysomal citrate synthase.

Glyoxysomal citrate synthase in pumpkin is synthesized as a precursor that has a cleavable presequence at its N-terminal end. To investigate the role of the presequence in the transport of the protein to the microbodies, we generated transgenic Arabidopsis plants that expressed beta-glucuronidase with the N-terminal presequence of the precursor to the glyoxysomal citrate synthase of pumpkin. Immunogold labeling and cell fractionation studies showed that the chimeric protein was transported into microbodies and subsequently was processed. The chimeric protein was transported to functionally different microbodies, such as glyoxysomes, leaf peroxisomes, and unspecialized microbodies. These observations indicated that the transport of glyoxysomal citrate synthase is mediated by its N-terminal presequence and that the transport system is functional in all plant microbodies. Site-directed mutagenesis of the conserved amino acids in the presequence caused abnormal targeting and inhibition of processing of the chimeric protein, suggesting that the conserved amino acids in the presequence are required for recognition of the target or processing.

Amino Acid Sequence↗
PubMed1996

Coupling of Metabolism and Bioconversion: Microbial Esterification of Citronellol with Acetyl Coenzyme A Produced via Metabolism of Glucose in an Interface Bioreactor.

Microbial esterification of citronellol with acetyl coenzyme A (acetyl-CoA) produced via metabolism of glucose was performed with Hansenula saturnus IFO 0809 in an interface bioreactor by using a hydrophilic carrier (an agar plate or an agar-coated filter pad) and a hydrophobic organic solvent (decane). An increase in the glucose concentration on an agar plate led to a decrease in oxidation of citronellol and an increase in the amount of citronellyl acetate. Fed-batch addition of citronellol efficiently alleviated substrate toxicity and resulted in the accumulation of high levels of citronellyl acetate. Furthermore, triple coupling of acetyl-CoA formation, microbial reduction of citronellal to citronellol, and esterification of the resulting citronellol with acetyl-CoA was also an efficient way to prepare citronellyl acetate. By using coupling systems, citronellyl acetate could be efficiently produced without any acetyl donor.

Journal Article↗
PubMed1996

Uninephrectomy reduces apoptotic cell death and enhances renal tubular cell regeneration in ischemic ARF in rats.

Contralateral uninephrectomy attenuates unilateral ischemic renal injury functionally and morphologically. In this study we investigated the effects of uninephrectomy on apoptotic renal cell death and tubular regeneration in ischemic acute renal failure (ARF) in rats. Unilateral ischemic injury was provoked by a 60-min left renal artery occlusion in right-nephrectomized (Nx) and sham-nephrectomized (sham-Nx) rats. Uninephrectomy attenuated tubular damage 48 h following the renal ischemia Apoptotic cells were found in renal tissue as early as 3 h after reperfusion and increased in number by 12 h. The "ladder" pattern of DNA fragments on agarose gel electrophoresis was also apparent in ischemic kidney. Uninephrectomy reduced apoptotic cells and DNA fragmentation. The expression of proliferating cell nuclear antigen (PCNA) could be seen 24 h after reperfusion and progressively increased thereafter PCNA expression in ischemic kidney was greater in Nx than sham-Nx rats at 24 h after renal reperfusion. These data suggest that uninephrectomy reduces apoptotic cells and DNA fragmentation and enhances PCNA expression. The reduced apoptotic cell death and enhanced cell regeneration may be importantly involved in the uninephrectomy-induced attenuation of ischemic acute renal failure in rats.

Acute Kidney Injury↗