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Biomedical subjects

S Masuda

Publications and source records attributed to S Masuda.

At least 397 records · Page 22Linked to original sources
PubMed1981

Distribution of fibrous long-spacing fibers in normal and pathological lymph nodes.

The occurrence and distribution of fibrous long-spacing fibers (FLS) of lymph nodes in normal and pathological conditions have been examined by electron microscopy. The FLS can be easily identified by the characteristic broad cross bands with a 90 to 120 nm period. In normal lymph nodes, the FLS were most often found in the stalk of the valve projecting into the lymphatic sinus and in the perivascular matrix, and less frequently in the wall of the vein, in the sinus wall and in the stroma of the medulla at the hilus. In pathological conditions, a large number of FLS appeared in the hyalinous matrix of lymphocyte depletion type of Hodgkin's disease. These fibers were also observed in reticular matrices of lymphosarcoma and mixed cellularity type of Hodgkin's disease as well as in granulation tissues. It was noted that FLS appeared to be formed in the regions where abundant reticular fibers were laid down. Compared with the ultrastructural and histological findings in various lesions of lymph nodes, the possible mechanism and significance of FLS were discussed.

Adult↗
PubMed1980

Polyclonal antibody production in murine spleen cells induced by Staphylococcus.

Polyclonal plaque-forming cell (PFC) responses in murine spleen cells induced by Staphylococcus aureus and S. epidermidis were studied. Injection of Balb/c mice with S. aureus strain 248 beta H resulted in the generation of anti-trinitrophenyl (TNP) and anti-sheep red blood cell PFC in their spleens. Cultures of Balb/c mutant yielded many anti-TNP PFC. The larger the number of organisms that were added to the cultures, the better was the PFC response. Both living and killed organisms were capable of inducing the response, but an excess of living 248 beta H organisms in the cultures abrogated the response. All of the organisms (12 strains of S. aureus and 11 strains of S. epidermidis) freshly isolated from patients had the ability to induce the polyclonal PFC response in cell cultures. These organisms stimulated cultured C3H/HcJ mouse spleen cells, which were unresponsive to bacterial lipopolysaccharide (LPS). Cultured cells from the spleens of athymic mice also responded to these organisms, and the number of PFC in nu/nu cell cultures was always greater than in nu/+ cells prepared from a haired litter mate. Moreover, the responses of nu/nu spleen were lower than expected. These findings suggest that the polyclonal PFC response to staphylococci is thymus independent, but that the magnitude of the response is regulated by mature T cells. Cultures of macrophage-depleted spleen cells responded to the organisms to an extent similar to that of the control. The 248 beta H organisms were less capable of stimulating spleen cells of 2-week-old mice (i.e., early maturing B cells) than LPS. However, spleen cells from adult (7-week-old) and aged (9-month-old) mice responded well to both the organisms and LPS. Previous sensitization with the organisms in vivo did not affect any polyclonal responses of spleen cells in vitro to either the organisms or LPS. The role of staphylococcal protein A in the polyclonal PFC response to staphylococci is discussed.

Aging↗
PubMed1980

Two siblings with hypophosphatasia.

Two siblings with hypophosphatasia, one of whom was autopsied, were reported. The first case which was a product of a 26-year-old mother complicated by hydroamnios represented poor mineralization of the entire bones on X-ray examination and died shortly after birth. The second case weighing 1850 g delivered from the same mother had a rhizomelic micromelia and poor visualization of the skull, long bones and vertebral bones on X-ray at postmortem. The autopsy on the second case showed small thoracic cage with rachitic rosaries of ribs, membranous skull and poorly ossified vertebral and long bones. Microscopically, there was a marked disturbance of both enchondral and membranous ossifications similar to the histology of rachitis. A biochemical examination showed low alkaline phosphatase, high calcium and normal PTH in the serum. Further examination of their family revealed relatively low level of alkaline phosphatase of the parents and one of their brothers which suggsted they were carriers of hypophosphastasia. Previous reports on hypophosphatasia were reviewed and differential diagnosis of hypophosphatasia from the other congenital dwarfisms was discussed.

Adult↗
PubMed1979

Preparation and characterization of an active lysozyme derivative: Kyn 62-lysozyme.

A novel method for the preparation of Kyn 62-lysozyme, in which tryptophan 62 is replaced by kynurenine, is reported. Hen egg-white lysozyme was ozonized in aqueous solution to yield one N'-formylkynurenine residue and deformylated with hydrochloric acid in frozen solution at -10 degrees C. Crude Kyn 62-lysozyme was purified by affinity and Bio Rex 70 chromatography successively. Kyn 62-lysozyme retains affinity for chitin and is essentially an active enzyme with a slightly weakened but distinct catalytic activity. After this modification, the enzyme activity was changed differently depending on the kind of substrate. At the individual optimum pH's, lytic activity was largely retained (80% active), but the catalytic efficiency for hydrolyzing glycol chitin was relatively low (30% active). Lysis of M. lysodeikticus cell suspensions was optimally catalyzed by Kyn 62-lysozyme at pH 6.2 and at 0.088 ionic strength. These values are lower by 1.3 pH unit and 0.04 ionic strength, respectively, than those of intact lysozyme. The optimum pH and ionic strength for the hydrolysis of neutral substrates were scarcely affected. These results suggest the significance of electrostatic interaction in the lysis of lysozyme. Relatively limited loss of activity induced by modification of the 62nd residue, which is thought to participate directly in the binding of the substrate at subsite C, is discussed on the basis of the similarity of side chain structure in tryptophan and kynurenine.

Amino Acids↗
PubMed1979

Physico- and immunochemical properties of staphylococcal protein A extracellularly produced by a set of mutants from Staphylococcus aureus Cowan I.

Mutant strains of Staphylococcus aureus have been isloated using a simple cosedimentation technique. While the parental strain contains predominantly a cell-bound protein A, the mutant strains exclusively produce extracellular protein A. The mutant forms of protein A all have lower molecular weights than that of protein A from the parental strain. They showed the same antigenicity as the parental protein A and gave similar reactivity with immunoglobulin to the parental one except for one mutant. A conspicuous spur was observed between the parental protein A and that produced by the mutant against normal dog serum in the micro-Ouchterlony immunodiffusion test.

Amino Acids↗