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Biomedical subjects

A Katoh

Publications and source records attributed to A Katoh.

At least 37 records · Page 2Linked to original sources
PubMed1998

Molecular interaction between proteins involved in EvgAS signal transduction of Escherichia coli.

EvgA and EvgS constitute one two-component signal transduction system in Escherichia coli. Although probable signaling domains of these proteins have been estimated, the molecular mechanism of their interaction remains to be elucidated. Here, we investigated protein to protein interactions between EvgA and EvgS and also between the EvgAS system and other related signaling pathways by means of surface plasmon resonance. EvgA and EvgS interacted directly and inhibition of phosphorylation of their functional domains abolished formation of the EvgAS complex. No interaction was observed either between EvgA and Bordetella BvgS or BvgA and EvgS. OmpR, a response regulator for the osmoregulative gene expression of E. coli, had similar but not identical behavior towards EvgS to that of EvgA. These results indicate that interaction between the signaling proteins is closely related to phosphorylation of the functional domain of the proteins.

Bacterial Outer Membrane Proteins↗
PubMed1998

Clinical significance of detecting p53 protein in Burkitt lymphoma and B-cell acute lymphoblastic leukemia using immunocytochemistry.

P53 protein expression in malignant cells of five patients with Burkitt lymphoma (BL) and from two patients with B-cell acute lymphoblastic leukemia (B-ALL) was examined with anti p53 protein monoclonal antibodies PAb1801, PAb240 and p53-D07 using an immunocytochemical technique. Four of the seven patients were positive. The distribution of positive staining within the cell was predominantly in the nucleus. The reactivity of PAb240 was weaker than that of the other antibodies. In addition, three of the four positive cases showed the same abnormal karyotype; translocation (8;14) (q24;q32). All of the four positive cases died due to relapse of their primary disease. The three negative cases did not show karyotypic abnormalities and are still alive and well. In conclusion, p53 immunostaining technique may be useful for predicting the clinical outcome of B-cell malignancy.

Adolescent↗
PubMed1997

Vasospastic angina induced by nonsteroidal anti-inflammatory drugs.

We report two cases of vasospastic angina associated with anaphylactic reaction caused by nonsteroidal anti-inflammatory drugs (NSAIDs). Both patients exhibited anaphylactic manifestations, such as general rash and urticaria, along with angina pectoris with electrocardiographic ST-segment elevations after suppository administration of diclofenac sodium or indomethacin, the most commonly used NSAIDs. Although these patients had normal coronary arteriograms, intracoronary administration of ergonovine or acetylcholine provoked diffuse coronary artery spasms accompanied by chest pain and ischemic ST-segment changes. It is therefore suggested that an allergic mechanism may be involved as a causative factor of the coronary artery spasm induced by NSAIDs.

Aged↗
PubMed1997

Anti-atherogenicity in women does not prevent restenosis after balloon angioplasty.

To test the hypothesis that anti-atherogenicity in women exerts beneficial effects to prevent restenosis formation after coronary angioplasty, we studied 493 men (988 lesions) and 81 women (159 lesions), aged 40-60 years, who had undergone successful balloon angioplasty and had follow-up angiography, 4.9 +/- 4.1 months later. We compared the extent of restenosis between men and women, and between pre- and post-menopausal women, which was assessed by a categorical definition of restenosis (more than 50% diameter stenosis at follow-up) and by percent diameter measured immediately after angioplasty and at follow-up. Hypertension was more frequent in women and a significantly lower percentage of women smoked. In women, the levels of total cholesterol and low-density lipoprotein cholesterol were higher. The location of dilated lesions, frequency of angioplasty for lesions with chronic total occlusion, and frequency of emergency angioplasty in patients with unstable angina or acute myocardial infarction were similar in men and women. Restenosis formation, estimated by the categorical definition or percent diameter, did not differ between men and women, or between pre- and post-menopausal women. Menopausal status or sex was not an independent predictor of restenosis by multivariate analysis. Thus, the benefit of anti-atherogenicity in women does not play an important role in preventing restenosis after coronary angioplasty.

Adult↗
PubMed1997

Size of cotA and identification of the gene product in Synechocystis sp. strain PCC6803.

cotA of Synechocystis sp. strain PCC6803 is a gene involved in light-induced proton extrusion (A. Katoh, M. Sonoda, H. Katoh, and T. Ogawa, J. Bacteriol. 178:5452-5455, 1996). There are two possible initiation codons in cotA, and either long (L-) or short (S-) cotA encoding a protein of 440 or 247 amino acids could be postulated. To determine the gene size, we inserted L-cotA and S-cotA into the genome of a cotA-less mutant (M29) to construct M29(L-cotA) and M29(S-cotA), respectively. M29(L-cotA) showed essentially the same net proton movement profile as the wild type, whereas no light-induced proton extrusion was observed with M29(S-cotA). Two kinds of antibodies were raised against partial gene products of the N- and C-terminal regions of L-cotA, respectively, fused to glutathione S-transferase expressed in Escherichia coli. Both antibodies cross-reacted with a band at 52 kDa in both cytoplasmic and thylakoid membrane fractions of the wild-type cells. The same cross-reacting band was present in the membranes of M29(L-cotA) but not in M29 or M29(S-cotA). These antibodies cross-reacted more strongly with the cytoplasmic membrane fraction than with the thylakoid membrane fraction. The antibody against NrtA, a nitrate transporter protein present only in the cytoplasmic membrane, also cross-reacted with the thylakoid membrane fraction strongly. Based on these results we concluded that CotA of 440 amino acids (51 kDa) is located in the cytoplasmic membrane. Whether CotA is absent in the thylakoid membrane remains to be solved.

Amino Acid Sequence↗
PubMed1997

[Rapid onset of hemolytic anemia after allogeneic bone marrow transplantation from an unrelated ABO major mismatched donor].

A 46-year-old woman with chronic myelogenous leukemia received allogeneic bone marrow transplantation from an unrelated human leukocyte antigen (HLA) matched (but mixed lymphocyte culture (MLC) positive to graft-versus host disease (GvHD) donor. The blood type of the recipient was A type Rh (+) while the donor blood type was B type Rh (+). The patient received busulfan 8 mg/kg, cyclophosphamide 120 mg/kg, and total-body irradiation 10 Gy before bone marrow transplantation. Short-term administration of methotrexate and cyclosporin was given for prophylaxis of GvHD. The mononuclear cells harvested from the donor were concentrated by COBE Spectra before bone marrow transplantation. Although engraftment of transplanted bone marrow in the recipient was confirmed on day 11, the patient suffered from severe anemia on day 10. Since the direct Coombs' test to A type red blood cells was positive, and anti-A antibody titer increased 16-fold, we diagnosed her anemia as hemolytic anemia caused by ABO mismatched transplantation. In addition to hemolytic anemia, she had skin symptoms of acute GvHD grade II, microangiopathic hemolytic anemia, and died of multiple organ failure on day 44. This experience indicated that some allogeneic transplant recipients are at risk of severe hemolytic anemia in the early stage after unrelated ABO mismatched donor and that it is necessary to establish proper treatment and prophylaxis.

ABO Blood-Group System↗
PubMed1997

Construction of a novel conjugative plasmid harboring a GFP reporter gene and its introduction into animal cells by transfection and trans-kingdom conjugation.

We have established a novel method of gene introduction into eukaryotic cells by trans-kingdom conjugation between Escherichia coli/Agrobacterium tumefaciens bacteria and yeasts. To expand this to animal cells, we have constructed a novel conjugative plasmid, pBASGreen which contains SV40-ori/promoter, pUC-ori, IncQ type oriT/mob, Apr and Neor genes with GFP (green fluorescent protein) gene as a reporter. The introduction into COS1 and NIH3T3 animal cultured cells by conventional transfection was easily detected by fluorescence of the GFP gene product under a fluorescent microscope and the transfectants were effectively selected by the Neor marker. By the action of oriT/mob in the presence of tra genes on a helper plasmid, pBASGreen was directly mobilizable from E. coli into animal cells by trans-kingdom conjugation.

3T3 Cells↗
PubMed1997

Genome structure of pTi-SAKURA (I): strategy for DNA sequencing of a Japanese cherry-Ti plasmid.

We isolated a plasmid from a bacterium Agrobacterium tumefaciens, which had been found in a crown gall tumor on a Japanese cherry tree SAKURA and designated it pTi-SAKURA. For complete DNA sequencing, we constructed a DNA library in lambda phage vector and developed a sequencing method by primer walking with long PCR and a PCR subcloning technique for long insert DNA.

Agrobacterium tumefaciens↗
PubMed1997

Genome structure of pTi-SAKURA (II): genetic map constructed by complete DNA sequencing.

Ti plasmid (pTi-SAKURA) DNA isolated from an agrobacterium pathogenic against Japanese cherry trees were completely sequenced by primer walking with PCR subcloning. Typical genes including transfer DNA (T-DNA), nopaline utilizing genes, trb genes, traI, rep genes, tra genes, acc and vir genes were assigned in this order to pTi-SAKURA. Between the rep genes and tra genes, we found a large region which essentially lacks homology to any sequences in DNA databases. By amino acid sequence search, we could pick up several ORFs which are homologous with genes putatively capable to enhance interaction between agrobacteria and plants.

Agrobacterium tumefaciens↗
PubMed1996

Novel anti-carcinogenic activity of an organosulfide from garlic: inhibition of H-RAS oncogene transformed tumor growth in vivo by diallyl disulfide is associated with inhibition of p21H-ras processing.

In this study, we report a novel anticarcinogenic activity of an organosulfur compound from garlic, diallyl disulfide (DADS). DADS treatment significantly inhibited the growth of H-ras oncogene transformed tumors in nude mice. As compared to controls, the appearance of tumors was also delayed markedly by oral administration of DADS. The inhibition of tumor growth by DADS treatment correlated with the inhibition of p21H-ras membrane association in the tumor tissue. The levels of membrane associated p21H-ras were markedly lower in the tumor tissues of DADS treated mice as compared to controls. An opposite trend, however, was evident for cytosolic p21H-ras. Furthermore, DADS treatment resulted in a significant inhibition of hepatic as well as tumoral 3-hydroxy-3-methylglutaryl coenzyme A reductase activity. These results indicate that DADS suppresses the growth of H-ras oncogene transformed tumors in nude mice by inhibiting the membrane association of tumoral p21H-ras.

Allyl Compounds↗
PubMed1996

cemA homologue essential to CO2 transport in the cyanobacterium Synechocystis PCC6803.

We have isolated mutants of Synechocystis PCC6803 that grew very slowly in a low-sodium medium, which is unfavorable for HCO3(-) transport, and examined two of these mutants (SC1 and SC2) for their ability to take up CO2 and HCO3(-) in the light. The CO2 transport activity of SC1 and SC2 was much lower than that of the wild type (WT), whereas there was no difference between the mutants and the WT in their activity of HCO3(-) transport. A clone containing a 3.9-kilobase-pair insert DNA that transforms both mutants to the WT phenotype was isolated from a genomic library of WT Synechocystis. Sequencing of the insert DNA in the region of mutations in SC1 and SC2 revealed an open reading frame (designated cotA), which showed significant amino-acid sequence homology to cemA encoding a protein found in the inner envelope membrane of chloroplasts. The cotA gene is present in a single copy and was not cotranscribed with any other gene(s). cotA encodes a protein of 247 amino acids containing four transmembrane domains. There was substitution of a single base in SC1 and two bases in SC2 in their cotA genes. A possible role of the cotA gene product in CO2 transport is discussed.

Amino Acid Sequence↗
PubMed1996

Changes in striatal dopamine release in stress-induced conditioned suppression of motility in rats.

Rats received a footshock for 10 min in a chamber with a metallic grid floor, and then placed into the chamber for 30 min after 6 days. The motility of the shocked rats showed a significant decrease (conditioned suppression of motility). In addition, the extracellular dopamine (DA) levels in the striatum were also reduced significantly in in vivo microdialysis study. Thus, dysfunction in the striatal DAergic neuronal systems is responsible for mental stress responses such as conditioned fear stress.

Animals↗
PubMed1996

Deficient cerebellar long-term depression, impaired eyeblink conditioning, and normal motor coordination in GFAP mutant mice.

Mice devoid of glial fibrillary acidic protein (GFAP), an intermediate filament protein specifically expressed in astrocytes, develop normally and do not show any detectable abnormalities in the anatomy of the brain. In the cerebellum, excitatory synaptic transmission from parallel fibers (PFs) or climbing fibers (CFs) to Purkinje cells is unaltered, and these synapses display normal short-term synaptic plasticity to paired stimuli in GFAP mutant mice. In contrast, long-term depression (LTD) at PF-Purkinje cell synapses is clearly deficient. Furthermore, GFAP mutant mice exhibited a significant impairment of eyeblink conditioning without any detectable deficits in motor coordination tasks. These results suggest that GFAP is required for communications between Bergmann glia and Purkinje cells during LTD induction and maintenance. The data support the notion that cerebellar LTD is a cellular mechanism closely associated with eyeblink conditioning, but is not essential for motor coordination tasks tested.

Animals↗
PubMed1996

Inhibition of experimental liver metastasis by combined treatment with tamoxifen and interferon.

The demonstration of estrogen receptors (ERs) in the liver has established it as a hormonally responsive organ. Estrogens have been imputed to have a role in the development of benign and malignant liver tumors. The detection of ERs in samples of normal liver tissue and in hepatocellular carcinomas suggested a treatment strategy with anti-hormonal drugs, i.e. tamoxifen, as used clinically for the treatment of breast cancer. The objective of this study was to test the effect of tamoxifen and tamoxifen in combination with other agents [5-fluorouracil (5-FU) and interferon (IFN)] against experimental liver metastases of human colorectal tumor cells xenografted into nude mice. A human colorectal tumor cell line, LoVo, was injected into the spleens of nude mice. This produces liver metastases in virtually 100% of the mice in 6-8 weeks. One week before tumor cell implantation, all mice were ovariectomized. Treatment was started 3 days after the intrasplenic injections. This consisted of 5 mg tamoxifen pellets (60-day release) implanted s.c., 5-FU given i.p. once a week for 4 weeks on a 46 mg/kg basis and IFN given s.c., daily for 4 weeks, 3 x 10(5) units/injection. The effect of tamoxifen alone on liver metastases was not significantly different from untreated controls. Tamoxifen in combination with IFN and 5-FU, however, resulted in 50-67% inhibition of liver metastases, as compared with the controls. The effectiveness of the treatment was in the order: tamoxifen + IFN > tamoxifen + 5-FU + IFN > tamoxifen + 5-FU. Thus, IFN may be useful as a potentiating agent in combination with tamoxifen for the treatment of estrogen-dependent tumors.

Adenocarcinoma↗
PubMed1996

Absence of light-induced proton extrusion in a cotA-less mutant of Synechocystis sp. strain PCC6803.

cotA of Synechocystis sp. strain PCC6803 was isolated as a gene that complemented a mutant defective in CO2 transport and is homologous to cemA that encodes a chloroplast envelope membrane protein (A. Katoh, K.S. Lee, H. Fukuzawa, K. Ohyama, and T. Ogawa, Proc. Natl. Acad. Sci. USA 93:4006-4010, 1996). A mutant (M29) constructed by replacing cotA in the wild-type (WT) Synechocystis strain with the omega fragment was unable to grow in BG11 medium (approximately 17 mM Na+) at pH 6.4 or at any pH in a low-sodium medium (100 microM Na+) under aeration with 3% (vol/vol) CO2 in air. The WT cells grew well in the pH range between 6.4 and 8.5 in BG11 medium but only at alkaline pH in the low-sodium medium. Illumination of the WT cells resulted in an extrusion followed by an uptake of protons. In contrast, only proton uptake was observed for the M29 mutant in the light without proton extrusion. There was no difference in sodium uptake activity between the WT and mutant. The mutant still possessed 51% of the WT CO2 transport activity in the presence of 15 mM NaCl. On the basis of these results we concluded that cotA has a role in light-induced proton extrusion and that the inhibition of CO2 transport in the M29 mutant is a secondary effect of the inhibition of proton extrusion.

Bacterial Proteins↗
PubMed1996

Isolation and characterization of the heat-responsive genes in Escherichia coli.

The ompC gene expression is induced by increasing temperature as well as osmotic pressure. In this study, a mutant (TD2) defective in this thermoresponse was isolated with transposon Tn10; the mutation was complemented by pMAN55 or pMAN56 containing micF and mapped at 48 min on Escherichia coli K-12. Furthermore, a new gene (hrsA) that suppressed the mutation was cloned. Its nucleotide sequence was analyzed and it was located close to the suc operon at 16.7 min corresponding to #18F11 (Kohara bank) on E. coli genome. In TD2 containing the hrsA on a multicopy plasmid, the ompC expression was induced and dependent on OmpR with increased temperature. The HrsA was found to have Enzyme IIA, IIB, and IIC domains that are homologous to Enzyme II, involved in the fructose-specific PTS (phosphotransferase system). The putative phosphorylation sites (His87 and Cys192) were also conserved in HrsA.

Amino Acid Sequence↗
PubMed1996

A new method for evaluating right ventricular dimensions and volume by cineangiography.

The aim of the present study was to establish a new method to evaluate the right ventricular dimensions and volume. Biplane right ventriculography of steep left anterior oblique view (LAO) and right anterior oblique view perpendicular to LAO were performed in 32 patients. The right ventricular volume and ejection fraction calculated from the three axial dimensions of the right ventricular cavity (the septum-free wall dimension, the anterior-posterior dimension, and either the long axis dimension or the tricuspid valve-apex dimension at end-diastole and end-systole) were well correlated to those from Simpson's method. In conclusion, we developed a new method for estimating right ventricular dimensions and volume.

Adolescent↗