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Biomedical subjects

C Kato

Publications and source records attributed to C Kato.

At least 127 records · Page 7Linked to original sources
PubMed1991

IgA-mediated inhibition of human leucocyte function by interference with Fc gamma and C3b receptors.

The inhibitory effects of IgA from human colostrum, and IgA1 and IgA2 from human serum on the chemiluminescence (CL) response and phagocytosis of polymorphonuclear leucocytes (PML) to Staphylococcus epidermidis and the CL response to formylmethionyl-leucyl-phenylalanine (FMLP) were studied. The dose-dependent inhibition of the luminol-mediated CL response of human PML to the bacteria was observed in the presence of more than 0.1 mg/ml IgA from both colostrum and serum. The preincubation of PML with a solution of IgA enhanced the suppressive effect of IgA on the cells. Removal of IgA from the reaction mixture after preincubation resulted in recovery, with time, of the response of PML to the bacteria. The bacteria treated with IgA did not give rise to any inhibition of the response. The CL response of PML to FMLP was not affected by the presence of IgA in the reaction mixture. The decrease of phagocytic activity of PML in the presence of IgA resulted in a decrease of NADPH oxidase activity of PML after stimulation with the bacteria as compared with the absence of IgA. The effect of IgA on the receptors of Fc and C3b (CR1) on the surface of PML was measured by monitoring erythrocyte-antibody (EA) or erythrocyte-antibody-complement (EAC) rosette formation and by direct and indirect immunofluorescence techniques using anti-CR1 antibody and Fc-specific antibodies. The presence of IgA in the reaction mixture led to a quantitative decrease in CR1 and the ability to bind IgG to the surface of PML.

Antigens, Differentiation↗
PubMed1990

Epstein-Barr virus infection of epithelial cells derived from primary cultures of adenoidal tissue.

Epithelial cells derived from primary cultures of adenoidal tissue were exposed to Epstein-Barr virus (EBV) from the throat washings of a patient with infectious mononucleosis (IM) and P3HR-1 and B95-8 cell strains. They were then examined for EBV-specific antigens by immunofluorescence. EBV from both the P3HR-1 cell strains and the throat washings of the IM patient infected the epithelial cells at the 6th and 9th days, respectively. Although the EBV-antigen-positive cells did not increase in number and disappeared at the 12th day after infection, EBV antigens of the virus's replication cycle could still be detected in the epithelial cells shed from cell culture layer at this time. However, the virus obtained from the cell-free 12th day's culture medium was incapable of transforming cord blood lymphocytes.

Adenoids↗
PubMed1990

Carboxyl-terminal deletion analysis of the Streptococcus mutans glucosyltransferase-I enzyme.

Sequential deletion of the carboxyl-terminal amino acids (including the six direct repeating units) of the glucosyltransferase-I (GTF-I) enzyme of Streptococcus mutans revealed differential effects on sucrase and GTF activities. Removal of all but one repeating unit resulted in a truncated enzyme with significant sucrase activity but no detectable GTF activity. These results are compatible with the presence of two functional domains in the enzyme.

Amino Acid Sequence↗
PubMed1990

Nucleotide sequence of the Streptococcus mutans gtfD gene encoding the glucosyltransferase-S enzyme.

The nucleotide sequence of the Streptococcus mutans GS-5 gtfD gene coding for the glucosyltransferase which synthesizes water-soluble glucan (GTF-S) has been determined. The complete gene contains 4293 base pairs and the unprocessed protein is composed of 1430 amino acids with a molecular mass of 159814 Da. The amino terminus of the unprocessed protein resembles the signal sequences of other extracellular proteins secreted by S. mutans and that of the GTF-I secreted by Streptococcus downei. In addition, the GTF-S protein exhibits high amino acid similarity with the strain GS-5 enzymes responsible for insoluble glucan synthesis (GTF-I, GTF-SI) previously isolated and sequenced in this laboratory. These results indicate that all three gtf genes evolved from a common ancestral gene.

Amino Acid Sequence↗
PubMed1990

[Quantitation of absolute and relative renal uptake using 99mTc-DMSA: sequential change in time and correlation with 99mTc-DTPA uptake].

A renal uptake of 99mTc-DMSA as a function of time and correlation between 99mTc-DMSA and 99mTc-DTPA in renal uptake were discussed. The absolute renal uptake of 99mTc-DMSA calculated by complete correction of tissue attenuation and physical decay showed increase by 5 hours after the administration, except one case with congestive heart failure. The net renal counts attained a maximum between 2 to 3 hours after the administration. There was a good correlation (r -0.992, p less than 0.001) between the relative renal uptake of 99mTc-DMSA (2 hour) and that of 99mTc-DTPA (2-3 min). On the contrary, the absolute renal uptake of 99mTc-DMSA as a indicator of total renal function showed a poor correlation (r = 0.419) to GFR calculated from 99mTc-DTPA. The results indicate that the relative renal uptake of 99mTc-DMSA is a reliable quantitative parameter for split renal function. However, the absolute renal uptake of 99mTc-DMSA may be suggested to be a different renal functioning indicator from GFR calculated from 99mTc-DTPA.

Adolescent↗
PubMed1990

[Captopril-enhanced renography using 99mTc-DTPA in renovascular hypertensive patients].

Dynamic renal scintigraphy with 99mTc-DTPA before (baseline renography: BS-RG) and 1 hour after administration of 25 mg to 50 mg of captopril (captopril-enhanced renography: CP-RG) was performed in a selected series of 18 patients suspected of having renovascular hypertension. Final diagnosis was made by angiography and further clinical follow-up. Eight patients were considered as renovascular hypertension (RVH), 6 with bilateral renal artery stenosis (BRAS) and 2 with unilateral renal artery stenosis (URAS). The remaining 10 patients were non-renovascular (non-RVH). Two criteria were prospectively employed for evaluating positive response induced by captopril. Glomerular filtration rate (GFR) on BS-RG (GFRbase) and on CP-RG (GFRcap) was estimated by early (120-180 seconds) DTPA uptake by the kidney, and then captopril response rate (CRR) was calculated in the following: CRR = (GFRcap-GFRbase)/GFRbase X 100 (%). CP-RG was considered positive when it was less than 20%. Renogram shape was also independently evaluated. CP-RG was also considered positive when either a delay of time to peak activity of more than 5 min or conversion of renogram shape to an obstructive or non-functioning pattern was observed. The sensitivity and specificity of CRR and change in renogram were 50% and 80%, 63% and 100%, respectively. In BRAS, positive response was observed in the unilateral kidney alone which maintained relatively a good renal function. CP-RG could not differentiate RVH with URAS from that with BRAS. Four patients were followed after the surgical or angioplastic treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

The complete nucleotide sequence of the glutamine synthetase gene (glnA) of Bacillus subtilis.

The glutamine synthetase (GS) gene from Bacillus subtilis PCI 219 was cloned in Escherichia coli using the vector pBR329. A plasmid, pSGS2, was isolated from a glnA+ transformant and the cloned GS gene was found to be located in a 3.6 kb DNA fragment. The nucleotide sequence of a 1.8 kb segment encoding the GS was determined. This segment showed an open reading frame which would encode a polypeptide of 444 amino acids. The amino acid sequence of this GS gene product has higher homology with that of the Clostridium acetobutylicum GS than that of the E. coli GS.

Amino Acid Sequence↗
PubMed1989

The nucleotide sequence of the lipo-penicillinase gene of alkalophilic Bacillus sp. strain 170.

The lipo-penicillinase (LIPEN) gene from an alkalophilic Bacillus sp. strain 170 was cloned in Escherichia coli using the vector pHSG399. A plasmid, pFAP121, was isolated from an ampicillin resistant transformant and the cloned LIPEN gene was found to be in a 2.2 kb DNA fragment. The nucleotide sequence of a 1.9 kb segment encoding the LIPEN was determined. This segment showed an open reading frame which would encode a polypeptide of 310 amino acids. The amino acid sequence of this LIPEN gene product has strong homology with those of the Bacillus cereus beta-lactamase III and Bacillus licheniformis penicillinase.

Amino Acid Sequence↗
PubMed1989

Construction of a secretion vector production of peptide hormones in Escherichia coli (extracellular production of calcitonin as fused protein).

A new secretion vector, pEAP84 which contained a unique restriction site (BglII) at the 3' end of the penicillinase gene to produce a fused protein, and the Ex-kil region to make the outer membrane permeable, was constructed from pEAP82. A recombinant plasmid p84h06, which contained a synthetic gene for human calcitonin with a cyanogen bromide cleavage site at the junction site of the fused protein, was constructed and introduced into Escherichia coli. The hybrid protein produced in E. coli carrying p84h06 was secreted into the culture medium. The amino acid composition of this product was consistent with that deduced from the DNA sequence. Mature calcitonin was obtained following cyanogen bromide cleavage of the fused protein.

Amino Acid Sequence↗
PubMed1989

Nucleotide sequence of the glutamine synthetase gene (glnA) and its upstream region from Bacillus cereus.

We have determined the complete nucleotide sequence of a 2.4 kb chromosomal EcoT22I-NspV fragment, containing the Bacillus cereus glnA gene (structural gene of glutamine synthetase). The deduced amino acid sequence indicates that the glutamine synthetase subunit consists of 444 amino acid residues (50,063 Da). Comparisons are made with reported amino acid sequences of glutamine synthetases from other bacteria. Upstrem of glnA we found an open reading frame of 129 codons (ORF129) preceded by the consensus sequence for a typical promoter. Maxicell experiments showed two polypeptide bands, with molecular weights in good agreement with that of glutamine synthetase and that of ORF129, in addition to vector-coded protein. It is possible that the product of this open reading frame upstream of glnA has a regulatory role in glutamine synthetase expression.

Amino Acid Sequence↗
PubMed1989

Two Bacillus beta-mannanases having different COOH termini are produced in Escherichia coli carrying pMAH5.

The nucleotide sequence was determined for the alkalophilic Bacillus sp. strain AM-001 beta-mannanase gene which produced two beta-mannanases (A and B) in Escherichia coli transformants. The putative beta-mannanase gene was 1,539 base pairs long and encoded a mature beta-mannanase protein of 487 amino acids and a signal peptide of 26 amino acids. The COOH-terminal amino acid of beta-mannanase A is an arginine residue located at amino acid 513 of the deduced amino acid sequence, and that of beta-mannanase B is a valine residue located at amino acid 365. Deletion derivatives having 1,098 base pairs from the ATG start codon maintained the beta-mannanase activity of the encoded polypeptide. However, clones harboring DNA fragments (1,051 base pairs) shorter than the gene which encoded beta-mannanase B (1,095 base pairs) did not exhibit the beta-mannanase activity. The simultaneous production of both beta-mannanases A and B in an E. coli transformant was demonstrated by the maxicell procedure.

Amino Acid Sequence↗
PubMed1989

[Suppressive effect of CDDP on induction of the Epstein-Barr virus antigen synthesis by n-butyrate].

n-Butyrate has been shown to induce Epstein-Barr virus (EBV) antigen synthesis in certain EBV genome-carrying lymphoblastoid cell lines. We have studied the effect of cis-dichloro-diamine-platinum (CDDP) on induction of EBV antigen synthesis not only by n-butyrate treatment of the EBV producer, P3HR-1 cells, but also by superinfection of EBV to the EBV non-producer, Raji cells. Simultaneous treatment of the cells with n-butyrate and CDDP or MMC blocked VCA and EA induction, but no suppressive effect was observed by the treatment of the cells with n-butyrate and Ara-C. The induction of EBV antigens was also observed in EBV-superinfected Raji cells, even in the presence of DNA synthesis inhibitor, CDDP or MMC. From these results, we discussed the mechanisms of the EBV antigens synthesis in EBV latently infected cells.

Antigens, Viral↗
PubMed1989

[Expression of an Epstein-Barr virus early antigen and cell fusion].

Superinfection of Raji cells with Epstein-Barr virus (EBV) derived from P3HR-1 (P3H-EBV) leads to syncytium formation. Studies using inhibitors of DNA and protein synthesis suggest that the fusion-inducing factor belongs to the early antigen of virus-specified proteins. Induction of early antigen (EA) in Raji cells by using various chemicals also leads to syncytium formation. However, A2L/AH hybrid cells, which were prepared by fusion between epithelial cells of adenoid origin and lymphocytes transformed by B95-8 virus, could not be superinfected with P3H-EBV. But, the syncytium formation was observed when EBV-EA was induced by chemicals in A2L/AH cells. It was considered that the synthesis of viral protein in superinfected Raji cells is essential for fusion and that the viral genes, inducible in Raji and A2L/AH cells by treatment with chemicals code for the necessary functions that lead to syncytia formation.

Antigens, Viral↗
PubMed1989

[Chemiluminescence response and phagocytic activity of murine polymorphonuclear leukocytes to various species of oral bacteria].

Polymorphonuclear leukocytes (PMN) are predominant cells in the gingival crevice and saliva, and may play an important role in oral bacteria. Murine peritoneal PMN was used and stimulated with 9 genera, 17 species of oral bacteria, including cariogenic and periodontal pathogens. The PMN response to the bacteria was measured by the luminol mediated chemiluminescence (CL) response and phagocytic activities, and the activities of lysozyme in the reaction medium after the CL response were also measured. The bacteria which could induce a high level of CL response of PMN were Fusobacterium nucleatum, Treponema denticola and Bacteroides gingivalis; middle grade were Staphylococcus subsp. and Actinomyces subsp.; low levels were Lactobacillus subsp., all 5 species of Streptococci and Enterococcus faecalis. Phagocytic indexes of PMN to various kind of bacteria were distributed from 8 to 40% and the bacterial numbers in 100 PMN were 27 to 301. There was no correlation between CL values and phagocytic indexes or between CL values and the bacterial number in 100 PMN by limiting the data on Staphylococcus, Streptococcus subsp. and Lactobacillus subsp., the correlation efficiency which was obtained between their values was r = 0.91 or 0.86. There was only a little in the lysozyme activities released from PMN by stimulation of various kind of bacteria, and the maximum difference corresponded to only 2.8% of the whole lysozyme activity of PMN. Either catalase activities or SOD activities were measured by H2O2 decomposition or the inhibition of xanthine oxidase activity using the intact bacteria. Neither of the enzyme activities of bacteria were closely related to the level of CL response.

Animals↗
PubMed1988

Saliva inhibits the chemiluminescence response, phagocytosis, and killing of Staphylococcus epidermidis by polymorphonuclear leukocytes.

Saliva inhibited several functional properties of polymorphonuclear leukocytes (PMNs) from murine peritoneal exudate, namely, luminol-mediated chemiluminescence (CL) induced by either Staphylococcus epidermidis or formylmethionyl-leucyl-phenylalanine (FMLP), phagocytosis, and killing of bacteria in vitro. The concentration of saliva in the reaction mixture that caused a complete inhibition of the CL response of PMNs to both S. epidermidis and FMLP was 25%. However, there was no catalase or superoxide dismutase activity in saliva that could influence the CL response of PMNs. The production of superoxide by PMNs stimulated with S. epidermidis was assayed in the presence or absence of saliva by inhibition of the reduction of cytochrome c by superoxide dismutase. In the presence of 50% saliva, O2- generation by PMNs was only 7.3% of that observed in the absence of saliva. After gel filtration of salivary material through Sephadex G-25 or Sephacryl S-200, several fractions were obtained that inhibited the CL response of PMNs to either FMLP or S. epidermidis or to both. Two inhibitory fractions were analyzed. One contained immunoglobulin A, and the other contained a peptide which was composed of 14 different amino acids. The two fractions of high molecular weight included in the first protein peak of Sephacryl S-200 gel filtration were able to inhibit the CL response to S. epidermidis and to inhibit phagocytic activity, while fractions of low molecular weight (under 12,500 Mr) inhibited the CL response to FMLP and to S. epidermidis but did not inhibit phagocytic activity.

Catalase↗