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Biomedical subjects

K Shimada

Publications and source records attributed to K Shimada.

At least 19 recordsLinked to original sources
PubMed1992

Photoaffinity labeling of the phylloquinone-binding polypeptides by 2-azidoanthraquinone in photosystem I particles.

A photoaffinity label, 2-azido-9,10-anthraquinone, binds at the quinone-binding (Q phi) site with high affinity and can substitute for the secondary acceptor, phylloquinone, in photosystem I reaction center of spinach. Phylloquinone-depleted photosystem I particles reconstituted with azido[3H]anthraquinone were illuminated with UV light and analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis. The large core polypeptides (psaA and/or psaB) were selectively labeled. The labeling was competitively inhibited in the presence of anthraquinone. These results indicate that the Q phi site is located on psaA or psaB polypeptides.

Affinity Labels↗
PubMed1992

A novel transthyretin mutation associated with familial amyloidotic polyneuropathy.

We characterized the mutation associated with familial amyloidotic polyneuropathy in a Japanese patient. Sequence analysis of polymerase chain reaction-amplified exons of the transthyretin gene revealed a novel point mutation resulting in a substitution of arginine for glycine at position 47. The mutation was confirmed using allele-specific olgonucleotide hybridization procedures. This most likely represents a de novo mutation since neither parent carries the mutant allele.

Adult↗
PubMed1992

Specific detection of acetyl-coenzyme A by reversed-phase ion-pair high-performance liquid chromatography with an immobilized enzyme reactor.

A selective chromatographic detection system for the determination of acetyl-coenzyme A (CoA) is reported. The short-chain acyl-CoA thioesters were separated by reversed-phase ion-pair high-performance liquid chromatography (HPLC), and then acetyl-CoA was selectively detected on-line with an immobilized enzyme reactor (IMER) as a post-column reactor. Thio-CoA liberated enzymatically from acetyl-CoA was determined spectrophotometrically after reaction with Ellman's reagent in the reagent stream. The IMER with phosphotransacetylase had a substrate specificity sufficient to determine acetyl-CoA and was active and stable in the mobile phase containing methanol and the ion-pair reagent. The calibration graph was linear between 0.2 and 10 nmol, with a detection limit of 0.05 nmol. This HPLC system with detection by IMER allows the selective identification and determination of acetyl-CoA in a mixture of acetoacetyl-CoA and 3-hydroxy-3-methylglutaryl-CoA, which are difficult to separate with ion-pair HPLC.

Acetyl Coenzyme A↗
PubMed1992

Determination of idebenone in rat serum and brain by high-performance liquid chromatography using platinum catalyst reduction and electrochemical detection.

A high-performance liquid chromatographic determination of idebenone, a new cerebral metabolism-improving agent, in rat serum and brain has been developed. After separation of idebenone on a reversed-phase column, idebenone was reduced once in a platinum catalyst reduction column connected on-line, then monitored quantitatively by electrochemical detection. A linear relationship between the peak-height ratio of idebenone to the internal standard and idebenone concentration was observed in the range 0.015-50 ng with a detection limit of 5 pg (signal-to-noise ratio = 5). This method was satisfactorily rapid and sensitive, and was successfully applied to the determination of idebenone in rat serum and brain tissues.

Animals↗
PubMed1992

Detection and quantification of anti-Ki antibodies by enzyme-linked immunosorbent assay using recombinant Ki antigen.

OBJECTIVE: To establish an enzyme-linked immunosorbent assay (ELISA) for detecting anti-Ki antibody, using a bovine recombinant Ki antigen, and studying its specificity. METHODS: Sera from 220 patients with various connective tissue diseases were screened, and a prospective study of fluctuations in anti-Ki antibody and clinical course of a woman with systemic lupus erythematosus (SLE) was analyzed, by ELISA: RESULTS: Anti-Ki antibodies were present in 18.9% of patients with SLE. The titer of anti-Ki antibody in the woman with SLE rose before the onset of pericarditis and pleuritis in this longitudinal study. CONCLUSION: ELISA using a recombinant Ki antigen is useful for the diagnosis of SLE, and it might be useful in estimating disease activity in patients with SLE.

Animals↗
PubMed1992

In vitro susceptibility of clinical isolates of Bacteroides fragilis and Bacteroides thetaiotaomicron in Japan.

A nationwide survey of the susceptibility of 433 isolates of Bacteroides fragilis and 149 isolates of Bacteroides thetaiotaomicron was conducted from December 1986 through November 1989 in Japan. These strains were collected from 16 university hospitals and one metropolitan hospital. Metronidazole was the most active drug against both species, with no resistant isolates found. The activity of imipenem and sulbactam-cefoperazone was good, with very low resistance rates determined in Bacteroides fragilis (1.4% and 1.6%, respectively) and in Bacteroides thetaiotaomicron (3.4% for both drugs), and was comparable to that of metronidazole. Cefoxitin, cefmetazole, cefotetan, cefbuperazone, latamoxef and ceftizoxime were found to be more active against Bacteroides fragilis, for which resistance rates were 3.2 to 9.5%, than against Bacteroides thetaiotaomicron, for which resistance rates were 18.1 to 21.8%. Rates of piperacillin resistance in the two species were 12.9% and 26.8%, respectively. Clindamycin was very active at a low concentration (MIC50 of 0.39 to 1.56 mg/l), but 24% and 27.5% of Bacteroides fragilis and Bacteroides thetaiotaomicron isolates, respectively, were resistant to this agent.

Anti-Bacterial Agents↗
PubMed1992

Interleukin 6 gene transcripts are expressed in atherosclerotic lesions of genetically hyperlipidemic rabbits.

We have investigated the involvement of interleukin 6 (IL-6), a growth-regulatory molecule for vascular smooth muscle cells (SMC), in the development of atherosclerotic lesions of Watanabe heritable hyperlipidemic (WHHL) rabbits. In in situ hybridization analysis, quite low levels of IL-6 mRNA were expressed in 'quiescent' SMC cultured from WHHL rabbits; however, high levels of IL-6 mRNA were induced in SMC exposed to 10% fetal bovine serum (FBS), suggesting that growth-stimulated SMC themselves can synthesize IL-6. In in vivo WHHL aortae, transcripts for the IL-6 gene were clearly observed in the fibrous plaques. These findings support the premise that IL-6 is an important autocrine and/or paracrine regulator of SMC proliferation and of pathogenesis of atherosclerosis in this animal model.

Animals↗
PubMed1992

Serum interleukin 6 levels become elevated in acute myocardial infarction.

We have examined serum interleukin 6 (IL-6) levels in 12 patients with acute myocardial infarction (AMI). IL-6 levels became elevated in all patients, following the rise of serum creatine kinase (CK) activity. Peak IL-6 levels showed a good correlation with peak serum C-reactive protein (CRP) levels, while there was no direct relationship between peak IL-6 levels and peak CK activity. IL-6 mRNA was not detected in unstimulated "quiescent" rat cardiocytes cultured in serum-free medium, but its expression was induced by exposure of the cells to serum or ionomycin. These results show that IL-6 is synthesized in the myocardium and serum IL-6 levels become elevated in AMI, suggesting that IL-6 could affect the progression and/or healing processes of AMI.

Aged↗
PubMed1992

Production and specificity of antisera raised against 25-hydroxyvitamin D3-[C-3]-bovine serum albumin conjugates.

In order to obtain specific antisera for use in the enzyme immunoassay of 25-hydroxyvitamin D3, three hapten-carrier conjugates having different lengths of bridges at the C-3 position were prepared from 25-hydroxyvitamin D3 by coupling with bovine serum albumin using the active ester method. The specificity of anti-25-hydroxyvitamin D3 antisera elicited in rabbits was tested by a cross-reaction study with closely related secosterols and by measuring the plasma levels of 25-hydroxyvitamin D3 by means of radioimmunoassay using tritium-labeled antigen. The results indicated that the specificity of the antisera obtained is higher than that of vitamin D-binding protein, and that some of these antisera are suitable for enzyme immunoassay.

Animals↗
PubMed1992

Detection of large COOH-terminal domains processed from the precursor of Serratia marcescens serine protease in the outer membrane of Escherichia coli.

The Serratia marcescens serine protease gene encoding a 1,045-amino-acid precursor protein of 112 kDa directs excretion of the mature protease of ca. 58 kDa through the outer membrane of Escherichia coli. A typical signal peptide of 27 amino acids and a large COOH-terminal domain of the precursor are both functionally essential for the excretion of the mature protease into the medium. Sequence analysis of the fragment peptides of the mature protease as well as site-directed mutagenesis indicated that the COOH-terminus of the mature enzyme was Asp645. By using the polyclonal antibody against the 112-kDa precursor protein, not only the intact precursor but also two proteins, C-1 (40 kDa) and C-2 (38 kDa), corresponding to the processed COOH-terminal domains were detected in the insoluble fraction of E. coli cells. Further fractionation by sucrose density gradient centrifugation showed that C-1 and C-2 were localized in the outer membrane. The NH2-terminal residues of C-1 and C-2 were determined to be Ala702 and Phe717, respectively. All these data suggest that the precursor is cleaved at three positions, between Asp645-Ser646, Glu701-Ala702, and Gly716-Phe717, probably by the self-processing activity in the normal excretion pathway through the outer membrane.

Amino Acid Sequence↗
PubMed1992

Enhanced spontaneous calcium efflux and decrease of calcium-dependent calcium release from the isolated perfused heart of spontaneously hypertensive rats.

OBJECTIVE: The aim of this study was to clarify the further details of calcium handling in hypertension. DESIGN: By preserving the physiological environment of cell membrane, whole hearts were used for comparison of calcium flux between spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. METHODS: Hearts from SHR and WKY rats were perfused with Krebs-Henseleit solution under constant flow and the effluent collected. RESULTS: After labelling of the heart with 45Ca2+ (100 mumol/l), 45Ca2+ binding was found to be saturated, and washing with calcium-free perfusion solution showed two exponential curves for calcium dissociation, indicating a fast (alpha-) and slow (beta-) phase. The half-lives of the beta-phase for both 4- and 8-week-old SHR were significantly shorter than those for age-matched WKY. Also in this phase, infusion of non-radioactive Ca2+ caused a transient dose-dependent release of 45Ca2+. A significant reduction in the amount of 45Ca2+ release induced by 2 mmol/l Ca2+ was observed in both 4- and 8-week-old SHR compared with age-matched WKY rats. Infusion of lanthanum, caffeine, ionomycin (calcium ionophore) and treatment of the hearts with ethyleneglycol-bis-(beta-aminoethylether)-N,N,N,',N'-tetraac etic acid did not alter 45Ca2+ release by non-radioactive Ca2+. From these observations, 45Ca2+ is presumably released from the intracellular calcium pool, and not from extracellular binding sites or sarcoplasmic reticulum. CONCLUSIONS: These findings suggest that an abnormal calcium-handling defect (enhanced calcium efflux and reduction of membrane-bound Ca2+) exists under physiological conditions before and after the onset of hypertension, and that this may be a primary characteristic of SHR.

Aging↗
PubMed1992

Suppressive effect of LD78 on the proliferation of human hemopoietic progenitors.

LD78 is a cDNA newly isolated from human stimulated tonsillar lymphocytes. The expression of LD78 is related to inflammatory responses and its structure has a homology with macrophage inflammatory protein 1-alpha, which is known to have an inhibitory effect on murine CFU-S. Using a colony assay technique, we examined the effects of LD78 on human hemopoietic progenitors. The addition of doses of 100 ng/ml or more of LD78 suppressed the colony formation of KMT-2, a factor-dependent myelomonocytic cell line established from cord blood cells; this suppressive activity was neutralized by the addition of antibody against LD78. The same doses of LD78 suppressed the formation of neutrophil, macrophage, and megakaryocytic colonies which were supported by human interleukin-3 and erythropoietin; however, LD78 did not affect colony formation by either non-phagocytic mononuclear cells or sorted CD34+ cells. The conditioned medium of KMT-2 cells or peripheral blood mononuclear cells cultured with LD78 suppressed colony formation by CD34+ cells. From these findings, it is suggested that LD78 affects phagocytic cells and induces factors that are inhibitory for hemopoiesis. We consider LD78 to be a new cytokine that plays an inhibitory role in hemopoiesis.

Bone Marrow↗
PubMed1992

Disseminated Pneumocystis carinii infection in a hemophiliac patient with acquired immunodeficiency syndrome.

A case of disseminated Pneumocystis carinii (PC) infection in a 28-year-old Japanese male hemophiliac with acquired immunodeficiency syndrome (AIDS) is reported. The patient had displayed a high fever and diffuse faint interstitial infiltrates on chest X-ray films without dyspnea three months before his death. At that time, no PC was detected after four consecutive induced sputum tests. Serum anti-cytomegalovirus (CMV) IgM was positive by EIA. No treatment for PC and CMV was given at the patient's request. Autopsy findings disclosed disseminated PC infection consisting of granulomas with caseation-like necrosis and frothy exudate in the lungs and disseminated organized calcification in the blood vessels of extrapulmonary organs. PC cysts and/or trophozoites were detected in these lesions.

Acquired Immunodeficiency Syndrome↗
PubMed1992

[Identification of mycobacteria by the acridinium-ester labeled DNA probes for M. tuberculosis and M. avium-intracellulare complex in culture and its clinical application].

The detectability of mycobacterium in culture by non-isotopic, chemiluminescent DNA probes for Mycobacterium tuberculosis (M. tuberculosis) and M. avium-intracellulare complex (MAC) was evaluated and compared with that by 125I-labeled DNA probe for the same mycobacteria. The sensitivity and specificity of the AE-DNA probes for MAC were 97.2% and 100%, respectively, for the conventional method and were both 100% for the 125I-labeled DNA probes. The detection limits of the AE-DNA probes tests for both M. tuberculosis and MAC were 10(5)-10(6) CFU/tube which were almost the same as those of the 125I-labeled DNA probes tests. Because the procedure is simple, rapid (it can be completed within 90 min), and safe (it does not use radioisotopes), it can be easily performed in any clinical laboratory.

Acridines↗
PubMed1992

Styrene formation by the decomposition by Pichia carsonii of trans-cinnamic acid added to a ground fish product.

It is not well known how the formation of styrene by microorganisms can occur in foods. In this study, we described and characterized the production of styrene by a yeast isolated from chikuwa fish paste. The styrene was not detected in fresh and normal food products nor in the food package's plastic film. The food containing styrene contained cinnamic acid as an antimicrobial agent and spice, and it was contaminated by 5.4 x 10(6) CFU of a yeast per gram. On the basis of morphological and biochemical features, the yeast isolated was determined to be a strain of Pichia carsonii, now designated strain CHI. Strain CHI, which was able to grow on cinnamic acid, had the ability to form styrene from trans-cinnamic acid via trans-p-coumaric and caffeic acids. The MIC of trans-cinnamic acid against strain CHI was 230 micrograms/ml. Strain CHI thrived well at pH 5.0 and 26.0 degrees C and was tolerant to 20% NaCl. Styrene was subsequently produced in ground fish meat containing cinnamic acid into which strain CHI had been inoculated. The yeast was found to be an environmental contaminant in food processing plants of the chikuwa manufacturer.

Biodegradation, Environmental↗
PubMed1992

Chromosomal localization of the mouse prealbumin gene (Ttr) by in situ hybridization.

Prealbumin is a serum protein which plays an important role in plasma transport of retinol and thyroxine. The accumulation of a variant prealbumin is associated with a hereditary disorder, familial amyloidotic polyneuropathy (FAP). In situ hybridization with a mouse prealbumin gene cDNA probe was carried out in mouse fibroblasts. Analysis of 114 R-banded metaphases showed that 13% of the total grains were located on chromosome 4 and 46% of the grains on this chromosome were in the region C6-D1. Linkage and syntenic group analysis showed that the prealbumin gene (Ttr) is located between two syntenic groups on mouse chromosome 4, which corresponded to two syntenic groups present on human chromosomes 1 and 9.

Animals↗