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Biomedical subjects

S Hamada

Publications and source records attributed to S Hamada.

At least 541 records · Page 30Linked to original sources
PubMed1976

Selective adsorption of heterophile polyglycerophosphate antigen from antigen extracts of Streptococcus mutans and other gram-positive bacteria.

Hot saline extracts of Streptococcus mutans have been shown to contain antigenic substances which occasionally react nonspecifically with some antisera against whole cells of various serological groups and types of streptococci. Chromatography of the extract of S. mutans strain MT703 (serotype e) on a diethylaminoethyl-Sephadex A-25 column gave two principal antigens. One antigen was eluted without adsorption to the resin and was identified as the serotype-specific polysaccharide. The other antigen, which contained a large quantity of phosphorus, was absorbed to and released from the resin by gradient elution. It was reactive against the antisera specific for polyglycerophosphate (PGP) from group A Streptococcus pyogenes and/or S. mutans strain Ingbritt (type c). The PGP antigen was further purified by gel filtration with Sephadex G-75. Two peaks, PGP-1, and PGP-2, were obtained. Each possessed the same antigenic specificity to anti-PGP serum as shown by immunodiffusion. Chemical analyses revealed that the molar ratio of phosphorus to glycerol in both was about 1:1, although the protein content between the two was significantly different. PGP antigen was found to be widely distributed in hot saline extracts from various gram-positive bacteria, with a few exceptions. However, all gram-negative bacteria examined were free of PGP. The PGP in the hot saline extracts of various gram-positive bacteria possessed an essentially identical antigenic specificity. The addition of diethylaminoethyl-Sephadex A-25 resin to hot saline extracts successfully removed the cross-reacting PGP antigen. After adsorption of the extract from S. mutans, the supernatant contained only type-specific polysaccharide antigen, except type b, in which both type b-specific polysaccharide and PGP antigens were absorbed with the resin. This simple procedure should be useful for the removal of the PGP-type teichoic acid from antigen extracts of bacteria that contain uncharged polysaccharides.

Antigens, Bacterial↗
PubMed1976

Adherence of serotype e Streptococcus mutans and the inhibitory effect of Lancefield group E and S mutans type e antiserum.

S mutans strain MT703 from an active carious lesion in the tooth of a child had type e specificity and showed a cross-reaction with the Lancefield group E cell wall streptococcal polysaccharide antigen. Heat-killed cells MT703 adhered to a glass surface in the presence of CGT MT703 and sucrose. Pretreatment of the cells with anti-MT703 whole cell serums inhibited adherecne. The removal of glycerol teichoic acid antibody and group E antibody from the MT703 serum did not result in a loss of inhibitory activity. Antiserum with or without adsorption significantly inhibited glucan synthesis by CGT from sucrose. Antibodies specific for the polyglycerol phosphate of teichoic acid did not inhibit adherence. Anti-group E serum and serums specific for other types of S mutans, did not show adherence inhibitory activity except for an occasional type c specific antiserum. Antibody specific for the type e antigen produced significant inhibition of the binding of CGT to the MT703 cell wall, and adherence of these cells did not occur. Antibody to CGT inhibited glucan synthesis. Treatment of the cells with dextranase, dextran antibody, or trypsin caused a significant reduction in adherence. The results suggest that the type antigen and dextran on the surface of the S mutans type e cell are functional in adherence, and that these polymers are associated with cell wall protein.

Glucose↗
PubMed1976

Demonstration and some properties of cytosol-binding proteins for thyroxine and triiodothyronine in human liver.

Cytosol-binding proteins for L-thyroxine (T4) and triiodo-L-thyronine (T3) were studied in human liver specimens obtained at autopsy from 5 male and 2 female subjects. The liver cytosol containing 131I-T4 or T3, together with or without added stable hormones, was fractionated by Pevikon thin-layer electrophoresis at pH 8.6, 8.0, and7.4. It was demonstrated in all the specimens that besides a small amount of serum T4-binding globulin, there existed three T4-binding proteins, termed hT4-1, hT4-2 and hT4-3, with the electrophoretic mobilities of alpha2- and beta-globulins, and two T3-binding proteins, termed hT3-1 and hT3-2, with the mobilities of gamma-globulin. Binding of hormones by the cytosol proteins was pH-dependent, and a preliminary dialysis had no effect on the hormone binding. The major band of T4, hT4-2, bound more than half the tracer T4, and possessed the maximal binding capacity of 110 mug/100 ml of 33% cytosol at pH 7.4. However, it showed no apparent affinity for T3, because the bound T4 could not be displaced with a T3 load of 600 mug/100 ml. The major band of T3, hT3-2, bound more than 70% of the tracer T3, and appeared to have a large capacity for the hormone although secondary binding sites on the same molecule might be responsible for the large capacity. The binding sites appeared almost specific for T3, because only a small, insignificant displacement was noted with a T4 load of 600 mug/100 ml. The results provide evidence for distinct binding proteins for T4 and T3 in the human liver cytosol, though their physiological roles remain to be elucidated.

Adult↗
PubMed1976

Roles of circulating carcinoembryonic antigen and calcitonin in diagnosis of medullary thyroid carcinoma: a comparative study.

Carcinoembryonic antigen (CEA) and calcitonin (CT) were simultaneously determined in sera and tumor tissues from 15 patients with medullary carcinoma of the thyroid (MCT). Serum CEA was increased in all but one patient, and CT did in all of them. Both levels were significantly related to the weight of excised tumor, but not to the presence of metastasis. Furthermore, a significant correlation was noted between the basal levels of CT and CEA. Both levels fell to normal after a radical operation had been performed. Tissue concentrations of CEA and CT in the MCT were more than 100 times those in hyperthyroidism, and the ratios of tissue over serum levels averaged 770 in CEA and 1000 in CT. In the calcium infusion test, CEA levels were not significantly changed in contrast with a distinct increase in CT levels. The results indicate that CEA and CT represent separate activities of the tumor cells, and that circulating CEA together with CT is a useful indicator in the diagnosis and follow-up of the disease.

Calcitonin↗
PubMed1975

Clinical evaluation of new indicators of free thyroxine concentration and thyroxine-binding globulin capacity.

A rapid and simple method is described for the indirect measurement of free thyroxine (T4) concentration and maximal thyroxine-binding globulin (TBG) capacity applying a single kit of Thyopac-4. Initially, a value for total T4 is determined, after which the patient's serum is added to permit estimation of T4 corrected for abnormal TBG concentration. The ratio of increased radioactivity in the supernatant after the addition of patient's serum to that obtained using pooled normal serum is designated the TBG index, being directly related to the amount of TBG in the added serum. The index is significantly increased in hypothyroidism and pregnancy, and decreased in hyperthyroidism, correlating well with the TBG capacity measured by reverse-flow paper electrophoresis. A free T4 index (FTI) can be calculated from the values for T4 and TBG index, because the TBG index is reciprocally related to the serum uptake test (T3-resin). Values for FTI are significantly increased and decreased in hyper- and hypothyroidism, respectively, whereas they remain within the normal range in pregnancy and TBG deficiency. The FTI is shown to bear a nearly straight-line relationship to that calculated from separate estimations of T4 and the serum uptake test (T3-resin).

Evaluation Studies as Topic↗
PubMed1975

Effect of dextranase on the extracellular polysaccharide synthesis of Streptococcus mutans; chemical and scanning electron microscopy studies.

A dextranase preparation (AD17) partially purified from a culture liquor of Spicaria violacea strain IFO 6120 significantly inhibited the formation of artifcial dental plaque on a steel wire or on an extracted tooth surface. Changes in the surface morphology of Streptococcus mutans cells due to AD17 action were studied using scanning electron microscopy. S. mutans cells grown in 5% sucrose-containing broth were coated with sticky amorphous capsule-like material, whereas cells grown in sucrose in the presence of AD17 or in glucose instead of sucrose did not synthesize such capsular material. AK17 degraded commercially available dextrans of molecular weight 7 X 1(04) and 2 X 10(6) to liberate glucose and various oligosaccharides, including isomaltose. On the other hand, AD17 hydrolyzed the extracellular polysaccharides (mainly glucan in nature) of some strains of S. mutans to a limited degree. Only 15 to 36% of the total polysaccharides were hydrolyzed by AD1M with little release of isomaltose. Prolonged incubation of the polysaccharides from S. mutans with AD17 did not release additional reducing sugars, which indicates that AD17 did not contain alpha-1,3-glucanase activity. These results suggest that glucosidic linkages which are susceptible to AD17 may play an important role in the adherence of S. mutans cells to smooth surfaces.

Dental Plaque↗