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Biomedical subjects

S Hamada

Publications and source records attributed to S Hamada.

At least 523 records · Page 29Linked to original sources
PubMed1978

A separation of staphylococci and micrococci based on serological reactivity with antiserum specific for polyglycerophosphate.

A serological reaction with the antiserum against heterophile polyglycerophosphate (PGP) was evaluated for genus level differentiation among strains of Staphylococcus and Micrococcus-Sarcina spp.. Hot saline extracts from whole cells of Staphylococcus spp. strongly reacted with the PGP antiserum, whereas those of Micrococcus-Sarcina spp. did not. Likewise, phenol-water extracts from whole cells of Micrococcus-Sarcina spp. were not reactive with the PGP antiserum, although the extracts of staphylococcal cells again gave a strong reaction with the antiserum. This study indicates that extracts from Micrococcus-Sarcina spp. have no antigen reactive with the PGP antiserum and can thus be differentiated from extracts of Staphylococcus spp. which react strongly with the PGP antiserum.

Antibodies, Bacterial↗
PubMed1977

Characteristic residual neuropathological features of Japanese B encephalitis.

Characteristic residual (12-67 years) neuropathological features of 4 verified or suspected cases of Japanese B encephalitis (JBE) are reported. These features are summarized as: 1. unique distribution pattern of the main lesions, i.e. combination of lesions in the thalamus, substantia nigra and Ammon's horn. Lesions in the thalamus consistently involved, in a linear fashion, lamina medullaris medialis with nucleus intralaminalis and adjacent portions of the nucleus lateralis thalami. Lesions in the substantia nigra usually occupied the middle parts of zona compacta. These lesions were usually symmetrical, though unequal in extent. 2. Unique nature of the lesions, especially those in the thalamus and substantia nigra. Characteristic "light circumscribed foci (LCF)", which consisted of small rarefied areas, with few cellular and fibrous elements, surrounded by dense gliomesenchymal scarring, were observed there and occasionally in cerebral cortices. Lesions were thought to be vestiges of "circumscribed necrotic foci" reported in the CNS of acute stage of JBE. Additional characteristic features in the thalamic lesions were calcified and binucleated nerve cells. Alzheimer's neurofibrillary tangles were not found. Authors consider that the distribution and nature of the lesions are of diagnostic value.

Adolescent↗
PubMed1977

Localization of carcinoembryonic antigen in medullary thyroid carcinoma by immunofluorescent techniques.

Cellular localization of carcinoembryonic antigen (CEA) in medullary thyroid carcinoma was studied in ethanol-fixed, paraffin-embedded specimens using the direct and indirect immunofluorescent techniques. It was demonstrated that CEA was present not only on the surface, but also in the cytoplasm of tumour cells. The immunofluorescence in the cytoplasm differed considerably in intensity from cell to cell. By contrast, no significant fluorescence was demonstrated in tissues of other types of thyroid adenocarcinoma, adenoma. Graves' disease and normal thyroid, with few exceptions. The results obtained indicate that CEA is actively produced by the tumour cells, and is present as a constituent of the cell membrane.

Carcinoembryonic Antigen↗
PubMed1977

Binding of lectins to Streptococcus mutans cells and type-specific polysaccharides, and effect on adherence.

The lectin concanavalin A (Con A) agglutinated the cells of 13 of 15 strains of the seven serotypes of Streptococcus mutans in an 18-h incubation period. Strains of types a, d, f, and g agglutinated within 2 h. Strains of a, d, and f were also agglutinated in 2 h by the castor bean lectin RCA. S. sanguis, S. salivarius, S. bovis, Actinomyces viscosus, A. naeslundii, and Lactobacillus plantarum were agglutinated within 2 h. The S. mutans type f polysaccharide was precipitated by Con A. The a, b, c, d, and e polysaccharides were not precipitated. Glucan from d and e strains of S. mutans and dextran T2000 were also precipitated by Con A. D-glucose inhibited the agglutination of type f cells by Con A and the agglutination of type d cells by D-galactose. The quantity of [acetyl-3H]Con A bound was not proportional to the degree of agglutination. Cells grown in sucrose medium bound more Con A than those grown in glucose medium. After treatment with dextranase, the sucrose-grown cells bound two- to fourfold more Con A. The binding of Con A to the type-specific polysaccharide or to teichoic acid could not be determined by the use of specific antibody due to the binding of Con A to the antibody globulin on the cell surface. Con A bound to S. mutans cells did not inhibit the activity of cell-bound glucosyltransferase, glucan synthesis, and in vitro adherence. Bound Con A also did not inhibit the ability of heat-treated cells to bind glucosyltransferase, synthesize glucan, and produce in vitro adherence.

Agglutination↗
PubMed1977

Ultracentrifugal characterization of cytosol-binding proteins for thyroxine and triiodothyronine in human liver.

Sucrose density gradient ultracentrifugation was performed on human liver cytosol containing double tracers of 131I-thyroxine(T4) and 125I-triiodothyronine(T3) together with or without large amount of stable hormones. Tracer T4 bound to the cytosol indicated 2 peaks of 8.3S and 4.7S, both of which were displaced with stable T4, but not with T3. Maximal binding capacity of the 8.3S component averaged 43.2 microgram/100ml of 33% cytosol. Tracer T3 in the cytosol showed a single peak of 4.2S which was displaced with stable T3 and also with T4. The results indicate thtat the human liver cytosol contains limited-capacity binding proteins: the one specific for T4, and the other relatively specific for T3.

Carrier Proteins↗
PubMed1976

Detection of circulating carcinoembryonic antigen (CEA) by counter-immunoelectrophoresis.

A sensitive method is described for detecting circulating carcinoembryonic antigen (CEA) by combined use of counter-immunoelectrophoresis and intensifiers. Perchloric acid extraction of serum was followed by counter-immunoelectrophoresis against monospecific antiserum to CEA. A precipitin line formed was intensified further by electrophoretic binding of anti-gammaG gamma-globulin and Amido Black staining. Less than 10 ng CEA/ml was detectable. Using this method, a total of 84 sera from patients with or without malignancy was examined. The results obtained were in general agreement with those reported by radioimmunoassay. The method appears to be useful as a diagnostic aid, since it requires neither labeled preparations of purified CEA nor special equipment for assay.

Antigens, Neoplasm↗
PubMed1976

Association of medullary carcinoma of the thyroid with carcinoembryonic antigen.

To investigate the association between medullary carcinoma of the thyroid (MCT) and carcinoembryonic antigen (CEA), we assayed 78 sera from patients with thyroid diseases for CEA, employing the radioimmunoassay of double antibody technique. All 13 sera from patients with MCT had high levels of CEA, ranging from 14 to 170 ng/ml. Increased serum CEA was noted even in cases of small, localized carcinoma. By contrast, serum CEA levels were normal (below 10 ng/ml) in all other histological types of thyroid carcinoma (33 cases), except for one case of papillary adenocarcinoma. In 32 patients with non-malignant thyroid diseases, with few exceptions serum CEA levels remained within the normal range. The elevated serum levels of CEA in MCT returned to normal after successful operation. Furthermore, very high tissue concentrations of CEA were demonstrated in MCT. The results indicate that CEA is actively produced by MCT, and that its measurement is useful in the diagnosis and management of the disease. It is suggested that the highly specific association of CEA with MCT may well be related to a defect of neural crest origin.

Carcinoembryonic Antigen↗
PubMed1976

Epidemiological survey of Streptococcus mutans among Japanese children. Identification and serological typing of the isolated strains.

An epidemiological investigation was carried out to identify and determine the serotypes of Streptococcus mutans from carious lesions of young Japanese children. For this purpose, a direct fluorescent antibody technique was mainly used. Fluorescein isothiocyanate-conjugated antibodies were prepared for the five known serotypes of S. mutans. Cross reactions and nonspecific reactions were eliminated by adsorption, counterstaining, or DEAE-cellulosecolumn chromatography. Agar-gel immunodiffusion was used to distinguish between serotypes a and d. The epidemiological survey suggested that serotype c strains were most prevalent in dental plaques of Japanese children. The d and e serotypes were rare and serotypes a and b were not detected. It was also noted that more than one serotype of S. mutans could be found in the same locus of a carious lesion and that there might be no relationship between the degree of caries and the causative serotype(s) of S. mutans.

Antibodies, Bacterial↗
PubMed1976

Inhibition of rat dental caries by dextranase from a strain of Spicaria violacea.

Dextranase AD17 obtained from a culture liquor of a strain of Spicaria violacea was assessed for its ability to inhibit the development of dental caries in conventional Sprague-Dawley rats which had been infected with one of the Streptococcus mutans strains. MT6R (serotype c), OMZ 176R (d), or MT-703R (e). These experiments showed that caries was significantly inhibited when rats were given cariogenic diets No. 2000 and drinking water containing AD17 at a concentration of 10 units/g, as compared to control rats not given dextranase. The inhibitory effects of AD17 were more prominent in smooth surface caries than in total caries. AD17 had a tendency to retard both the establishment of inoculated S. mutans and plaque deposition on tooth surfaces. However, S. mutans could be implanted in the rat oral cavity after repeated inoculation of the bacteria, even in the presence of AD17. These results suggest that the anticaries activity of AD17 is due to not only inhibition of adherence of S. mutans cells on tooth surfaces but also to physiochemical changes of dental plaque formed under the enzymatic action of AD17. Preliminary histophatological examination showed that AD17 had no significant toxicity in rats.

Animals↗
PubMed1976

Chemical and immunological properties of the type f polysaccharide antigen of Streptococcus mutans.

The type-specific cell wall polysaccharide antigen was extracted, purified, and characterized from type f Streptococcus mutans strain OMZ175 and MT557. The antigen was extracted from lyophilized cells with 5% trichloroacetic acid at 85 C for 15 min or saline at 120 C for 30 min. The trichloroacetic acid antigen was chromatographically separated into three antigenic fractions on a diethylaminoethyl-Sephadex A-25 column. Antigen 1 (Ag1P), which was specific for type f antiserum, was further purified by passing through carboxymethyl-Sephadex C-25 and Sephadex G-200 columns. It was a polysaccharide composed of 49% rhamnose and 47% glucose. No reaction was obtained with anti-polyglycerophosphate (PGP) serum. Antigen 2 was reactive with both type f and PGP antisera and contained significant amounts of protein and phosphorus. Antigen 3 was reactive only with PGP antiserum and had no type specificity. The polysaccharide antigen gave a single precipitin band against type-specific antiserum on immunodiffusion and immunoelectrophoresis. The presence of alpha-1,6-glucosidic linkages was indicated by a 90% inhibition of the precipitin reaction by isomaltose and alpha-methyl-D-glucopyranoside, adsorption to and release from a concanavalin A-Sepharose column, and reaction with an S. mutans (type e) glucan antiserum. This antiserum was used to show that the type f polysaccharide antigen did not contain free glucan. An analysis of the antigen released from the antigen-glucan antiserum complex showed the presence of rhamnose and glucose. This released antigen also reacted with an f antiserum, which did not react with commercial dextran. The results show that the type f polysaccharide antigen is the first of those S. mutans type-specific polysaccharides identified to be immunologically related to an S. mutans glucan.

Antigens, Bacterial↗
PubMed1976

Purification and immunochemical characterization of type e polysaccharide antigen of Streptococcus mutans.

The type-specific antigen of Streptococcus mutans strain MT703, serotype e, has been chromatographically purified and characterized. Two chromatographic fractions were obtained from saline extracts which reacted with both anti-MT703 whole-cell serum and Lancefield group E serum. The major fraction (eI) was identified as a polysaccharide composed of 37% glucose, 56% rhamnose, 5% protein, and 0.3% phosphorus, whereas the minor fraction (eII) contained 66% protein in addition to 10% glucose and 17% rhamnose. The immunological specificity of these antigens was found to be the same by immunodiffusion in agar gel. Another fraction with a negative charge (eIII) reacted with polyglycerophosphate antisera from Streptococcus mutans and Streptococcus pyogenes. For comparison, the MT703 antigen in a hot trichloroacetic acid extract (eA) and the group E antigen from a saline extract of cells of strain K129 (EI) were similarly purified by anionic ion-exchange chromatography. Although the ratio of glucose and rhamnose in eA was 1:0.9 and in eI and eII approximately 1:1.5, reactions of identity were obtained in gel diffusion against specific anti-e serum. This difference in ratio is probably a result of the extraction procedures. Both the type e and group E antisera were reactive with both eI and EI antigens. The adsorption of group E antiserum with MT703 cells removed all E antibody, whereas type e-specific antibody remained after adsorption with K129 cells. These results suggest that eI antigen possesses both e and E specificities, whereas EI possesses E only. These findings were supported by the quantitative precipitin test and immunodiffusion and/or immunoelectrophoretic patterns in agar gel. Methyl-beta-D-glucopyranoside markedly inhibited the precipitin reaction in both type e and group E sera. However, a significantly stronger inhibition by cellobiose of type e serum than of group E serum indicates that a beta-linked glucose-glucose dimer is the predominant antigenic determinant of the e specificity. The presence of both e and E specificities on a single polysaccharide molecule was demonstrated by the use of purified e antigen released from a specific e-anti-e complex. This antigen reacted with a group E-specific serum as well as a type e-specific serum. An examination of five S. mutans type e strains showed the presence of group E specificity also, whereas the I, II, and IV serotypes of group E streptococci only possessed the group E specificity.

Antigens, Bacterial↗