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Biomedical subjects

S Hamada

Publications and source records attributed to S Hamada.

At least 451 records · Page 25Linked to original sources
PubMed1982

Effect of a glucosyltransferase inhibitor on glucan synthesis and cellular adherence of Streptococcus mutans.

The effects of mutastein, a glucosyltransferase inhibitor derived from an Aspergillus terreus strain, on the glucan synthesis by glucosyltransferases of Streptococcus mutans and sucrose-dependent adherence of S. mutans cells were examined in vitro. The synthesis of insoluble glucan by crude glucosyltransferase of S. mutans strain B13 was markedly inhibited by mutastein at a final concentration of 10 micrograms of protein/ml. The synthesis of insoluble glucan adherent to glass surfaces was almost completely inhibited by mutastein at this concentration. In addition, mutastein inhibited the sucrose-dependent adherence to glass surfaces of resting and growing cells of various S. mutans strains. These results suggest that mutastein could be useful for controlling dental plaque and dental caries in vivo.

Adhesiveness↗
PubMed1982

Novel antigens of oral Actinomyces species prepared from a cell wall enzyme lysate.

Purified cell walls of Actinomyces viscosus and Actinomyces naeslundii were solubilized by the enzymatic action of Ml N-acetylmuramidase. Soluble cell wall carbohydrate antigens were purified by column chromatography. A purified antigen preparation (fraction C) from A. viscosus ATCC 19246 was found to contain deoxyhexoses (rhamnose and 6-deoxytalose), hexosse (galactose, glucose and mannose), and a peptidoglycan component. This preparation gave a single precipitin band against antiserum to homologous whole cells. Similar antigen preparations were purified from Ml enzyme lysate of A. viscosus SK4 and A. naeslundii ATCC 12104 cell walls.

Actinomyces↗
PubMed1981

Carcinoma of the maxillary sinus with eosinophilia. Report of a case.

A patient with carcinoma of the maxillary sinus presented with a blood eosinophilia and infiltration of eosinophilic leukocytes into the tumor tissue. Immediately after cancer therapy with intraarterial infusion of 5-fluorouracil into the superficial temporal artery, necrotomy and resection of the maxilla including radical neck dissection, the number of eosinophilic leukocytes was suddenly decreased and thereafter a transient increase in blood eosinophilic leukocyte count was observed. In this communication, a tentative mechanism for these events is suggested.

Carcinoma, Squamous Cell↗
PubMed1981

Adherence of Streptococcus sanguis clinical isolates to smooth surfaces and interactions of the isolates with Streptococcus mutans glucosyltransferase.

Streptococcus sanguis isolated from human dental plaque were grown in Todd-Hewitt broth. Cells were collected by centrifugation and lyophilized after extensive washing with water. The cell-associated glucosyltransferase (GTase) activities of S. sanguis strains were assayed with [14C]sucrose. Strain differences in GTase activity were significant within the same serotype or biotype or both. The ability of S. sanguis cells to adhere to smooth glass surfaces was generally weak, irrespective of significant cell-associated GTase activity synthesizing water-insoluble, gel-like glucans. Resting cells of most S. sanguis strains bound extracellular GTase from Streptococcus mutans strain B13 (serotype d), resulting in the strong adherence of the S. sanguis cells to smooth glass surfaces in the presence of sucrose. Conversely, S. mutans B13 cells also could bind extracellular GTase from some strains of S. sanguis examined. The sucrose-dependent adherence of S. mutans cells was not altered, although S. sanguis strains from which the extracellular GTases were obtained did not produce significant adherence in the presence of sucrose. In view of these findings, it was suggested that S. mutans GTase could affect the adherence of S. sanguis to smooth tooth surfaces in the oral cavity.

Binding Sites↗
PubMed1981

Plasmid specifying total degradation of 3-chlorobenzoate by a modified ortho pathway.

A plasmid, termed pAC25, specifying biodegradation of 3-chlorobenzoate in a strain of Pseudomonas putida has been characterized. During growth of the plasmid-harboring cells with 3-chlorobenzoate, there was an accumulation of 3-chlorocatechol and beta-chloromuconic acid as intermediates and release of more than 80% of the chlorine in the form of inorganic chloride. The plasmid had a mean molecular mass of 68 x 10(6) daltons and was transmissible to a number of Pseudomonas species such as P. aeruginosa, P. putida strain PpG1, and P. putida strain PRS1. Transfer of pAC25 to various catechol-negative mutants of P. putida strain PRS1 showed that the chromosomally coded pyrocatechase was not complemented by the plasmid-specified pyrocatechase, which appeared to be specific for the chlorinated catechols. In contrast to benzoate, which was metabolized by the ortho pathway through beta-ketoadipate as an intermediate, the plasmid specified ortho cleavage of the chlorocatechols through maleylacetate as an intermediate.

Catechol 1,2-Dioxygenase↗
PubMed1981

Susceptibility of rats, hamsters, and mice to carious infection by Streptococcus mutans serotype c and d organisms.

Susceptibility of rats, hamsters, and mice to carious infection by S. mutans serotypes c and d was compared. S. mutans serotype c induced a similar level of carious lesions at experimental periods of 68, 82, and 98 d in rats, hamsters, and mice, respectively. On the other hand, S. mutans serotype d developed a high level of caries at those experimental periods in rats and hamsters, whereas in mice it showed weak caries activity.

Animals↗
PubMed1981

Lymphoid cell responses to bacterial cell wall components: mitogenic responses of murine B cells to Streptococcus mutans carbohydrate antigens.

The mitogenic activity of various purified serotype carbohydrate and cell wall lysate fractions of Streptococcus mutans for murine lymphocytes has been determined. The highest mitogenic responses occurred after 48 hr of stimulation with these carbohydrate preparations when tested on splenic cultures derived from C3H/HeJ and BALB/c mice. The response pattern obtained with optimum concentrations of these preparations was very similar to that seen with the B cell mitogen, LPS. A purified serotype g carbohydrate (M1 g) prepared by mutanolysin enzyme treatment of S. mutans 6715 cell walls stimulated good mitogenic responses in BALB/c nude and nu/+ splenic cultures, suggesting an effect on mouse B cells. This was further substantiated by studies showing that this antigen also induced responses in cultures of B cells purified by nylon wool fractionation, whereas purified T cells did not respond. Mitogenic responses were due to the carbohydrate moiety and not to possible LPS contamination, since alkaline treatment or mixture with polymyxin B greatly reduced responses to LPS; however, no alteration of mitogenic responses to M1 g occurred. Further, LPS nonresponsive C3H/HeJ spleen cells yielded good mitogenic responses to M1 g. On the other hand, periodate treatment, which is known to decompose carbohydrate moieties completely abrogated the mitogenic activity of M1 g antigen. Additional studies with serotypes c and e carbohydrate, which also induced mitogenic responses, suggested that this activity for lymphoid cells may be a common property of S. mutans cell wall carbohydrate.

Animals↗