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Biomedical subjects

T Hamada

Publications and source records attributed to T Hamada.

At least 847 records · Page 47Linked to original sources
PubMed1982

Ultrastructural and physicochemical studies on glycogen macromolecules from ascites hepatoma AH 13 cells. A comparison with normal adult rat muscle, liver and fetal liver glycogen.

Glycogen extracted from rat ascites hepatoma AH 13 cells was compared with that from adult rat liver, adult rat muscle, and fetal rat liver 3 days before delivery, by electron microscopic, biochemical and physicochemical techniques. The ascites hepatoma AH 13 glycogen revealed two major different types of glycogen macromolecules by sucrose discontinuous density gradient centrifugation. The glycogen of the light fraction was very similar to rat muscle glycogen macromolecules in its size and shape except that it exhibited a stronger Cotton effect on measurement of the optical rotatory dispersion and circular dichroism than the muscle glycogen. Furthermore, this light material different from normal muscle glycogen. The other glycogen which also included very small amounts of irregular particles of glycogen macromolecules was contained in the heavy fraction was very similar to the adult rat liver glycogen macromolecules which did not display the Cotton effect. Electron micrographs showing the ultrastructure of the glycogen particles extracted from the AH 13 cells by negative staining revealed a variety of size and shape, and they contained two types of glycogen macromolecules with the smaller muscle types and larger adult type of liver glycogen macromolecules. The glycogen macromolecules also formed varied irregular structures in conformation.

Animals↗
PubMed1981

Oral kinesthesia in patients with Duchenne muscular dystrophy.

In trials on normal subjects and patients with Duchenne muscular dystrophy (DMD), interdental dimension discrimination (IDD) was tested by assessing the ability of subjects to discriminate between pairs of sticks of different dimensions held between the upper and lower teeth. The IDD ability of the DMD patients was significantly inferior to that of the normal subjects. Further, DMD patients tended to overestimate the dimension of the first stick of each pair even more than did normal subjects. Vibration applied to the mandible seemed to lessen such inaccuracies of oral kinesthesia in the DMD patients. These results are compatible with the idea that muscle receptors, especially muscle spindles in jaw closing muscles, are mainly responsible for IDD.

Adolescent↗
PubMed1981

A method of head restraint in unanesthetized cats by using frontal sinus.

Two stainless steel bolts were implanted and fixed parallel in the frontal sinus of cats with dental acrylic and screws. When unanaesthetized, the head was fixed to a frame by securing the bolts to an acrylic plate. This arrangement provides a quick, rigid and safe fixation of the head without any signs of discomfort.

Animals↗
PubMed1981

Monovalent monomer derivative of concanavalin A produced by photochemically induced alkylation.

Irradiation of tetrameric concanavalin A with a high-pressure mercury lamp in the presence of chloroacetamide and fractionation of the reaction product by affinity chromatography gave a lectin derivative showing a monomeric molecular weight at pH 7.4, with an overall yield of 25%. It retained the intact binding ability against methyl-alpha-D-glucopyranoside. Hemagglutination and glycogen precipitation data suggested the monovalent nature of the derivative. The results of amino acid composition analyses indicated that the photochemically induced alkylation at one or two tryptophan residues per subunit of concanavalin A may be responsible for the dissociation into monovalent monomers which are stable at physiological pH.

Acetamides↗
PubMed1981

Age-related changes in human dermal elastic fibres.

Age-related changes in human dermal elastic fibres were studied by scanning (SEM) and transmission (TEM) electron microscopy. The SEM findings showed an increase in the complexity of shape and arrangement of the fibres including flattening and branching, an increase in the roughness of the surface, and a decrease in interfibrillar areas. The TEM findings showed a decrease in micro-fibrils and amorphous material, and an increase in electron dense inclusions followed by the appearance of vesicular structure.

Adult↗
PubMed1981

Cutaneous ultrastructural diagnosis of ceroid-lipofuscinosis.

A skin biopsy from a 6-year-old girl was examined by electron microscopy and the diagnosis of ceroid-lipofuscinosis (CL) was confirmed. This has not been reported in the dermatology literature, because of the absence of specific skin manifestations. However, as we have shown, various cells of skin, including fibroblasts, Schwann cells, eccrine serous cells, endothelial cells and smooth muscle cells, accumulated characteristic substances to produce the finger print pattern (FPP) or the curvilinear profile (CLP) which are thought to be diagnostic for CL. Cutaneous ultrastructural research in such cases is important as asymptomatic skin disorders may exist in other congenital storage diseases.

Ceroid↗
PubMed1981

Comparison of the mannan structure from the cell-wall mutant Candida sp. M-7002 and its wild type. I. Characterization of the proteo-mannan from the mutant and the wild-type cells.

The cell-wall mutant of a hydrocarbon-assimilating yeast, Candida sp. M-7002 and its wild type have shown a significant difference in mannose content. Each mannan was isolated from the mutant and the wild-type cells by fractionation with Cetavlon and copper reagent. Both mannans contain D-mannose, D-glucose and phosphate. The mutant mannan has a relatively high content of protein (18% in weight bases) whereas the wild-type mannan has a low protein content (5.1%) with a high amount of carbohydrate (greater than 90%). Structural analyses by enzymatic and chemical methods showed that both mannans had a mannosidic (alpha 1--6)-linked back bone substituted at O-2 by side chains of varying length. The side chains of the mutant mannan were shown to consist of single mannose units and disaccharide units whose linkages were predominantly alpha 1--2, while the wild-type mannan had two additional side chains of disaccharides. These additional side chains had alpha 1--3 linkages which were scarcely found in the mutant mannan. beta-Elimination reaction demonstrated that the mannans also contain mannosyl oligosaccharides linked to protein through O-glycosidic linkage. The chemical properties of the mannan of the Candida mutant indicates that the mutation might occur not only in the side chain structure but also in the (alpha 1--6)-linked mannan back bone.

Candida↗
PubMed1981

Comparison of the mannan structure from the cell-wall mutant Candida sp. M-7002 and its wild type. II. Immunochemical properties of the mannans.

The structure of the proteomannans from the cell-wall mutant Candida sp. and its parent strain was further studied by immunochemical methods. Alkaline titration showed that the phosphate is present in the form of diester and mild acid treatment released mannose from both of the mannans. In the wild-type mannan, the phosphorylated side-chain oligosaccharides gave 85% inhibition and a mannopentaose side chain having alpha 1--3 linkage in the nonreducing terminal also gave 40% inhibition in the homologous precipitin reaction. This indicates that the immunodominant side chain of the Candida sp. wild type mannan is the phosphorylated mannopentaose which has an (alpha 1--3)-linked nonreducing terminal. In the mutant system, a significant reactivity in the cross reaction between the mutant antiserum and Kloeckera brevis mannan indicates that the immunodeterminant of the mutant mannan may be a structural analogue of the side-chain oligosaccharide from K. brevis, which has phosphorylated (alpha 1--3)-linked mannotriose. However, no definite results were obtained in the inhibition studies. On the basis of the results from chemical, enzymatical and immunological experiments, the side-chain structure and macromolecular models of Candida sp. wild-type and mutant mannans are proposed.

Antigen-Antibody Complex↗