Search PubMed⌕ Search

Biomedical subjects

Y Fukazawa

Publications and source records attributed to Y Fukazawa.

At least 73 records · Page 4Linked to original sources
PubMed1988

Heterogeneity of hemolytic efficiency and isoelectric point of streptolysin O.

Using thin-layer agarose gel isoelectric focusing overlaid with thin-layer erythrocyte agar plates, we found that crude streptolysin O (SLO) consisted of a variety of hemolytic components with different isoelectric points (pIs) and that the distribution of pIs in crude SLO was different even in samples which were produced from a single strain of Streptococcus pyogenes under similar conditions. All of the hemolytic components in crude SLO were shown to have the properties of SLO with respect to their susceptibility to oxygen and anti-SLO serum and their molecular weight. The SLO components showed a single molecular weight of 64,000, but they exhibited various pIs ranging from pH 5.4 to 8.3, with major components showing a pI of 6 and/or 7.5. Further examination revealed the slope of the hemolytic titration curve to be dissimilar among the samples of crude SLO. Since the slope of the hemolytic titration curve of a component appears to be based on its hemolytic efficiency, the value of the slope was designated its hemolytic efficiency index. When SLO was purified by isoelectric focusing, the pI of the components was correlated with its hemolytic efficiency index; hemolytic components with lower pIs exhibited a lower hemolytic efficiency index. These results indicate that SLO consists of heterogeneous components with different pIs and suggest that the differences in hemolytic efficiency indices of SLO components are due to the different electrical charges of SLO molecules, which are related to their polymerization and affect hemolytic efficiency.

Animals↗
PubMed1988

Host defence mechanisms against fungal infection.

Recent concepts on the role of non-specific (normal) and specific (immune) defence mechanisms against fungal infection are discussed on the basis of the evidence obtained from experimental animals. Commonly occurring systemic mycoses, i.e. candidosis (candidiasis), cryptococcosis and histoplasmosis, are discussed.

Animals↗
PubMed1987

Enhancement of resistance to Escherichia coli infection in mice by dihydroheptaprenol, a synthetic polyprenol derivative.

The effect of a chemically synthesized polyprenol derivative, dihydroheptaprenol (DHP), on the nonspecific resistance of mice to infection with Escherichia coli was investigated. Mice that had been injected intramuscularly with 100 mg of DHP per kg of body weight, prepared as a microemulsion with lecithin, 1 to 4 days before infection showed enhanced resistance to subcutaneous (s.c.) infection with E. coli. When DHP-injected mice were inoculated s.c. with 3 X 10(8) E. coli, which induces fatal acute systemic infection in normal mice, propagation of bacteria in the blood, liver, and spleen was significantly inhibited. Enhanced resistance of athymic (nude) mice to E. coli infection was also induced by DHP. DHP markedly stimulated the generation of peripheral blood neutrophils, significantly enhanced clearance of E. coli from the bloodstream, and activated neutrophils and peritoneal macrophages for H2O2 generation. DHP restored the resistance to E. coli infection in cyclophosphamide-treated mice over the normal level. Furthermore, DHP shortened the period of the recovery of neutrophils and also enhanced clearance of E. coli from the bloodstream in cyclophosphamide-treated mice. DHP was nontoxic for mice and rats (400 mg/kg intramuscularly and 800 mg/kg s.c.) and nonpyrogenic at a dose of 30 mg/kg when administered intravenously to rabbits. These results suggest that the mechanism of action of DHP for enhancing resistance in mice may be, at least in part, its ability to stimulate the generation of potent neutrophils and to activate macrophages in the reticuloendothelial system.

Animals↗
PubMed1986

Production and characterization of agglutinating monoclonal antibodies against predominant antigenic factors for Candida albicans.

Two clones, CA4-2 and CA5-4, which produced agglutinating monoclonal immunoglobulin M (IgM) antibodies (MAbs) against mannan antigens of Candida albicans serotype A, were established. The specificity of each MAb was determined by slide agglutination tests for cross-reactivity patterns against the homologous and six other strains of Candida and a strain of Torulopsis: C. albicans serotype B, C. tropicalis, C. guilliermondii, C. krusei, C. parapsilosis, C. pseudotropicalis, and Torulopsis glabrata. The MAb produced by CA4-2 reacted with the homologous, C. tropicalis, and T. glabrata strains, whereas the MAb produced by CA5-4 reacted with the homologous, C. albicans serotype B, and C. tropicalis strains. These results are consistent with results obtained by comparative experiments with several strains of each serotype or species. Specificity of these two MAbs by agglutination was also consistent with the cross-reactivity patterns demonstrated by indirect immunofluorescence staining. The competitive binding experiments by immunofluorescence staining with two MAbs and polyclonal factor sera (PAb factors) 5 and 6 suggested that the MAb from clone CA4-2 did not completely correspond to PAb factor 6 and that the MAb from CA5-4 was distinct from PAb factor 5 in its manner of binding to determinants (the latter was designated 5b), Cross-reactivity patterns, however, furnished evidence that these two MAbs could replace the known PAb factors 6 and 5, respectively, as reagents for aid in the identification of the strains of C. albicans and their serotypes.

Agglutination↗
PubMed1986

Evaluation of direct and rapid identification of group A streptococci from throat swabs by Culturette 10-Minute Group A Strep ID test kit.

The Culturette Brand 10-Minute Group A Strep ID test kit (Marion Scientific, Division of Marion Laboratories, Inc., Kansas City, Mo.) was evaluated for its sensitivity and specificity in identifying the group A streptococci directly from 96 throat swabs, against the conventional culture method and serological grouping test. Our results indicated that the rapid test kit and conventional method are 93.8% accurate; percent sensitivity and specificity of the rapid test was 80.6% and 100%, respectively. None of the false-positive observed in rapid test kits occurred with the heterogeneous microorganisms. More than 8 X 10(4) colony forming unit per swab was required for the positive latex agglutination of the test kit. Since the Culturette method is simple to perform and correctly identifies group A streptococcal antigen, and also required no special instruments, it appears to be applicable in hospital laboratories and outpatients clinics.

Bacteriological Techniques↗
PubMed1985

Electrophoretic patterns of extracellular deoxyribonuclease (DNase) and their correlation with T-type in group A streptococci.

Molecular heterogeneity of the extracellular deoxyribonuclease (DNase) in group A streptococci was demonstrated in 42 clinical isolates. Although polyacrylamide gel electrophoretic patterns of the extracellular DNase of all the isolates were heterogeneous, they could be divided into five main patterns with respect to the presence or absence of three DNase components including DNase B. By comparing the electrophoretic patterns of DNase in all the isolates with their T-types, we found that the patterns were quite characteristic for their T-types, especially in the prevalent T-types 12 and 1, and that the isolates of T-types 12 and 1 produced DNase B as their major extracellular DNase. Relative DNase B activity in the total extracellular DNase activity of group A, B, and G isolates was determined by the rapid method of neutralization with anti-DNase B antibody. The results showed neutralization of DNase activity in all the isolates of group A streptococci, largely corresponding to their T-types, but not of the isolates of groups B and G. These results indicate that the electrophoretic patterns of the extracellular DNase of group A streptococci are closely correlated with their T-types, suggesting the physicochemical taxonomic value of these properties.

Antibodies, Bacterial↗
PubMed1985

Characterization of pathogenic constituents of Cryptococcus neoformans strains.

We examined seven strains, comprising five serotypes, of Cryptococcus neoformans to determine what constituents of the organisms are responsible for pathogenicity and virulence in BALB/c mice. C. neoformans strains were divided into three virulence classes by survival rates after intravenous inoculation of 1 X 10(5) or 1 X 10(7) viable cells, and virulence was found not to be correlated with serotype or capsular size. C. neoformans cells resisted phagocytosis in different degrees in the presence of normal serum. Sensitivity of the C. neoformans strains to singlet oxygen ranged from resistance to susceptibility. Histological examination revealed that a weakly encapsulated virulent strain induced inflammatory responses with granuloma formation in the liver, lung, and kidney in addition to formation of cystic foci in the brain. In contrast, although the heavily encapsulated virulent strain produced granulomatous lesions in the liver, this strain preferably produced mucinous cystic foci in the lung, kidney, and brain. Correlation between virulence, and biological, histopathological and physiological evidence suggests that C. neoformans strains are endowed with the implicated multiple pathogenic constituents in various degrees and proportions. The following are suggested as the most important pathogenic constituents: a polysaccharide capsule responsible for resistance to phagocytosis and formation of cystic foci; a cell surface structure for responsible for resistance to intra- or extracellular killing and induction of the granulomatous lesion; a growth rate suitable for interacting with phagocytic elimination.

Animals↗
PubMed1985

Chemical characterization of capsular polysaccharide from Cryptococcus neoformans serotype A-D.

During a study of serotyping of Cryptococcus neoformans, we found that the type strain of C. neoformans (CBS 132) was serotype A-D. This strain agglutinated with both factor 7 serum (specific for serotype A) and factor 8 serum (specific for serotype D) in our serotyping system. Therefore, we investigated the chemical structure of the antigenic capsular polysaccharide of this strain. The soluble capsular polysaccharide was obtained from the culture supernatant fluid by precipitation with ethanol. Column chromatography of the polysaccharide on DEAE-cellulose yielded three fractions (F-1 to F-3). The major antigenic activity was found in the F-3 fraction. The results obtained by methylation analysis, controlled Smith degradation-methylation analysis, partial acid hydrolysis, and other structural studies of F-3 polysaccharide indicated that the polysaccharide contains mannose, xylose, and glucuronic acid at a ratio of 7:2:2, and has a backbone of alpha (1-3)-linked D-mannopyranoside residues with a single branch of beta (1-2)-xylose and glucuronic acid. The ratio of mannose residues with or without a branch in the F-3 polysaccharide was 4:3 and its molecular weight calculated from the average of the degree of polymerization was 46,500 daltons. These results indicate that the chemical structure of the capsular polysaccharide of serotype A-D is very similar to those from serotypes A and D, suggesting that small differences in the molar ratio and pattern of linkage of monosaccharides in the branch of the polysaccharides of the three serotypes may be responsible for their different specificities.

Antigens, Bacterial↗
PubMed1984

Biological and biochemical characterization of macrophage activating factor (MAF) in murine lymphocytes: physiocochemical similarity of MAF to gamma interferon (IFN-gamma).

During the course of an investigation designed to separate macrophage activating factor (MAF) activity from interferon (IFN) antiviral activity in the lymphokine-rich fraction (LKF) produced by stimulation of murine splenic cells with concanavalin A (Con A), we found molecular evidence for the similarity of the two activities. MAF activity was expressed as the rate of inhibition of intracellular growth of Salmonella typhimurium in macrophages based on the linear correlation between relative MAF activity and LKF concentration. The antiviral substance in LKF was identified as IFN-gamma based on the observation that its activity was inactivated at pH 2 and neutralized with anti-mouse IFN-gamma serum but not with anti-mouse IFN-alpha/beta serum. MAF and IFN antiviral activities displayed identical sensitivity to pH 2 and temperature. Further, neither activity was affected by beta-mercaptoethanol, but both were inactivated by guanidine hydrochloride and by sodium dodecyl sulfate, suggesting that the structures related to conformation of the protein of the two molecules may be similar. In affinity chromatography of the LKF on a Con A-Sepharose column, MAF and IFN activities were found in both the nonadsorbing (F I) and adsorbing (F II) fractions. However, the rates of F II of MAF and IFN activities increased proportionally when the sample was applied on a column of higher capacity, suggesting that the molecular structure of the mannose-containing glycosyl moiety of the two molecules may also be similar. Moreover, the intact or modified form of MAF and IFN activities of different LKF preparations showed a strong correlation, indicating that the production and denaturation of MAF activity were proportional to those of IFN antiviral activity. The results of this study provide strong evidence that MAF and IFN antiviral activities may reside in virtually the same molecular species.

Animals↗
PubMed1984

Antigenic relationship between Candida parapsilosis and Candida albicans serotype B.

We examined the antigenic relationship between Candida parapsilosis and C. albicans serotype B with respect to antigenic factors 13 and 13b, specific for the former species and common to both species, respectively. Acetolysis of C. albicans serotype B cell-wall mannan gave six oligosaccharides. Their chemical structure was determined by 1H-nuclear magnetic resonance (NMR) spectroscopy, methylation analysis, and partial acid hydrolysis. The structure of the hexasaccharide derived from C. albicans serotype B mannan was alpha-D-Manp-(1-2)-alpha-D-Manp-(1-3)-alpha-D-Manp-(1- 2)-alpha-D-Manp-(1-2)- alpha-D-Manp-(1-2)-D-Man (M6) which is identical to that from C. parapsilosis mannan. Inhibition of two precipitin reaction systems (anti-C. albicans serotype B serum and anti-C. parapsilosis serum to the respective homologous mannan), by oligosaccharides from homologous and heterologous mannans indicated that M6 from either C. albicans serotype B or C. parapsilosis was the most effective inhibitor. Moreover inhibition of the agglutination reaction between factor serum containing anti-factors 13 and 13b and C. albicans serotype B or C. parapsilosis cells by oligosaccharides from both mannans also indicated that the M6s were the most effective inhibitors. These results suggest that the M6s derived from the two species are identical in their chemical structure, although the structures of the whole mannans of the two species are not identical as demonstrated by gel diffusion precipitation patterns, and that M6s may be involved in the specificities of antigenic factors 13 and 13b. The amount of M6 is larger in C. parapsilosis cell-wall mannan, suggesting that high repeating frequency of M6 fragment may induce the antibody specific for C. parapsilosis.

Antigens, Fungal↗
PubMed1984

Role of serum factors in the phagocytosis of weakly or heavily encapsulated Cryptococcus neoformans strains by guinea pig peripheral blood leukocytes.

We investigated the opsonic activity of the serum factors affecting phagocytosis of Cryptococcus neoformans in vitro to elucidate the role of humoral factors in the host defense mechanisms against cryptococcosis. Two strains of C. neoformans, one heavily and one weakly encapsulated, were used. Guinea pig peripheral blood leukocytes (PBLs) were used for phagocytosis. The viable weakly encapsulated cells were ingested effectively by PBLs, in the presence of guinea pig normal fresh serum, while the heavily encapsulated cells were not ingested. Neither immune serum, its IgG fraction alone, nor heated serum promoted the phagocytosis of either the weakly or heavily encapsulated strain. On the other hand, immune serum promoted adherence of PBLs to viable cells of the heavily encapsulated strain, forming rosettes in the presence of fresh serum. A substantial amount of C3b component was detected on yeast cells when weakly encapsulated cells were incubated with human fresh serum, or heavily encapsulated cells were incubated with rabbit immune serum together with human fresh serum. Serum chelation experiments also indicated that the factors involved in the alternative complement pathway are opsonins for the weakly encapsulated strain. These results suggest that the alternative pathway plays an important normal opsonic role for weakly encapsulated strains and that specific antibody plays an immune opsonic role for heavily encapsulated strains of C. neoformans via the classical pathway of complement activation.

Animals↗
PubMed1984

Comparative study of streptococcal DNase by rapid and quantitative assay systems.

Clinical isolates of group A, B, and G streptococci were compared in regard to their extracellular deoxyribonuclease (DNase) activities by the modified assay system for DNase using DNA-methyl green complex as a substrate. DNase activity in a culture supernatant of each strain was measured as a percent decrease in the substrate-specific absorbance at 640 nm. After 1 hr incubation, DNase activities in all the strains of group A streptococci were found to be markedly higher than those of any strain in the other groups, although the DNase activities in groups B and G were considerably heterogeneous. These findings were also seen when commercially available DNA-dye complex reagent for the determination of anti-DNase B antibody titer was used as a substrate in the assay system. Our results suggest that this newly established assay system could be applicable for the rapid measurement of DNase activity to distinguish group A streptococci from the other groups.

Bacteriological Techniques↗
PubMed1983

Immunochemical determinant of Candida parapsilosis.

Acetolysis of Candida parapsilosis cell-wall D-mannan, obtained by alkali extraction and purified as a copper complex, gave six oligosaccharides by Bio-Gel P-2 filtration. Their chemical structure was examined by 1H-n.m.r. spectroscopy, methylation analysis, and partial acid hydrolysis. The structures of the penta- and hexa-saccharide were alpha-D-Manp-(1 leads to 3)-alpha-D-Manp-(1 leads to 2)-alpha-D-Manp-(1 leads to 2)-alpha-D-Manp-(1 leads to 2)-D-Man (M5) and alpha-D-Manp-(1 leads to 2)-alpha-D-Manp-(1 leads to 3)-alpha-D-Manp-(1 leads to 2)-alpha-D-Manp-(1 leads to 2)-alpha-D-Manp-(1 leads to 2)-D-Man (M6), respectively. Inhibition of the oligosaccharides with anti-C. parapsilosis serum and homologous D-mannan indicated that although M5 and M6 exhibited strong inhibitory-activity, M6 was the more effective inhibitor, and suggested that M6 may be the immunodominant or may be responsible for the specificity of C. parapsilosis mannan in the precipitin-reaction system, or both.

Antigens, Surface↗
PubMed1983

Mating types and serotypes of Cryptococcus neoformans isolated in Japan.

Thirty-two isolates of Cryptococcus neoformans from patients and one from the wild obtained in Japan were characterized for their serotype, self-fertility, and mating behaviour by crossing them with two mating types of Filobasidiella neoformans var. neoformans and F. neoformans var. bacillispora. Of the 32 isolates from patients, 31 were of serotype A and the remaining one was of serotype D. Although these 32 isolates were all self-sterile, 23 serotype A and one serotype D isolates produced a complete sexual state when mixed with the alpha mating type of F. neoformans var. neoformans. The one natural isolate was of serotype A-D and self-fertile. The Japanese clinical isolates of C. neoformans appear to be predominantly serotype A and alpha mating type of F. neoformans var. neoformans as is the case in the U.S.A.

Conjugation, Genetic↗