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Biomedical subjects

C Katagiri

Publications and source records attributed to C Katagiri.

83 records · Page 5Linked to original sources
PubMed1982

Splenic white pulp as a thymus-independent area in the African clawed toad, Xenopus laevis.

An indirect immunofluorescence study of the frozen sections of the spleen of an anuran amphibian, Xenopus laevis, showed that lymphocytes bearing a small amount of immunoglobulin (Ig) were localized mostly in the white pulp of non-immunized toads. There were fewer fluorescent cells in the red pulp. In the toads hyperimmunized with human gamma globulin (HGG), cells with strong cytoplasmic fluorescence increased significantly in the outer part of the white pulp. Electron microscopy of spleens from these toads showed that plasma cells at different stages of maturation were abundant in the white pulp, whereas in the red pulp, a smaller number of maturer plasma cells were observed. These results indicate that, in contrast with its mammalian counterpart, the splenic white pulp of this anuran is the site where thymus-independent lymphocytes commence blast formation and transformation into plasma cells.

Animals↗
PubMed1981

Hydrogenation of plasma lipoproteins by a water-soluble catalyst; its use as a structural probe.

Hydrogenation of double bonds of fatty acyl chains in the lipids of individual, intact plasma lipoproteins has been accomplished using a water-soluble, homogenous catalyst. Up to 40% of the double bonds can be hydrogenated. The pattern of hydrogenation is similar for each of the lipoprotein fractions; the phospholipids are most extensively hydrogenated but small amounts of cholesteryl ester and triacylglycerol are also hydrogenated. This results is consistent with a surface location of phospholipids and with the majority of the apolar lipids being in a hydrophobic inner core since the catalyst was shown not to be specific for an individual lipid class. It also suggests the some cholesteryl ester and triacylglycerol may be near the lipoprotein surface, accessible to the catalyst. If this is the case, it is speculated that the known exchange of these neutral lipids between the lipoprotein classes and their degradation by lipolytic enzymes may thus be facilitated.

Cholesterol Esters↗
PubMed1976

Restoration of immune responsiveness in early thymectomized xenopus by implantation of histocompatible adult thymus.

Larvae of the South African clawed toad, Xenopus laevis, were thymectomized at Nieuwkoop and Faber stages 45-46 (4-5 days after fertilization). The 1-1.5-year-old thymusless toads thus obtained were implanted with histocompatible thymus from 1-year-old toads, and 4 weeks later were given skin allografts or rabbit red blood cells (RRBC) to determine their immune response. In contrast with the perfectly tolerant thymusless controls, the thymus-implanted toads rejected skin allografts after longer survival times (25-66 days) than the nonthymectomized controls (18 - 19 days). Accelerated rejection (15 - 27 days) of the second-set skin allografts was evident in the thymus-implanted individuals. Similarly, the capacity of antibody production against RRBC was restored to the thymus-implanted toads to roughly the normal extent. Implantation of thymus also restored the histological features of the spleen in thymectomized toads. The experiments clearly demonstrate that in Xenopus the thymus plays an essential role for immunity at the early stages of its histogenesis. The restorative capacity of the adult thymus is also stressed.

Animals↗