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S Shigeta

Publications and source records attributed to S Shigeta.

347 records · Page 20Linked to original sources
PubMedDate not supplied

Characterization of immunosuppressive factors expressed in serum by rat tolerogenic liver transplantation.

BACKGROUND: In a rat tolerogenic model of orthotopic liver transplantation (OLT), recipient serum after OLT (post-OLT serum) possesses strong immunosuppressive activity. This study aimed to identify immunosuppressive factors present in early post-OLT serum. METHODS: Immunosuppressive activity was evaluated in vitro by inhibition of the mixed-lymphocyte reaction (MLR). Autoantigens recognized by MLR-inhibitory IgG were identified by the internal protein sequencing. RESULTS: Recipient post-OLT serum inhibited MLR, and OLT-inducible IgG was the major immunosuppressive factor. IgG from post-OLT sera (2 to 3 weeks) specifically reacted to 31; 34; and 73-kd autoantigens on spleen cells. The internal sequences of the 31- and 34-kd antigens coincided completely with those of histone H1 molecules. Immunodepletion of anti-histone H1 antibodies (Abs) from early post-OLT serum abolished the MLR-inhibitory activity. Furthermore, rabbit polyclonal Ab-directed histone H1 not only significantly suppressed rat and human MLR but also prolonged survival of heart allografts. Flow-cytometric analysis revealed that some live PVG splenocytes were stained with antihistone H1 Abs, and that these positive cells increased on Con A stimulation. Western blot analysis indicated that several cross-reactive antigens against anti-histone H1 Abs were found in their membrane fraction. CONCLUSIONS: In this study we provide evidence that autoreactive Abs, against histone H1 are a major OLT-induced graft survival factor, and may play at least a part in overcoming the acute rejection phase to establish solid allograft tolerance.

Animals↗
PubMedDate not supplied

Pseudomonas cepacia typing systems: collaborative study to assess their potential in epidemiologic investigations.

To determine the utility of available Pseudomonas cepacia typing systems for confirming the relatedness of isolates, we applied these methods to isolates associated with previously investigated nosocomial outbreaks. We compared chromosome analysis, serologic reactions, biochemical tests, bacteriocin production and susceptibility, and antimicrobial susceptibility in their ability to determine outbreak relatedness. Chromosome analysis, serologic reactions, and biochemical tests were each demonstrated to be epidemiologically useful methods for typing isolates. Determination of the sensitivity and specificity of these typing techniques will facilitate their application in the epidemiologic study of this increasingly important nosocomial pathogen.

Chromosomes, Bacterial↗
PubMedDate not supplied

gamma-Glutamyl transpeptidase activity in liver of alcoholics and its localization.

The activity and the histochemical localization of gamma-GTP in the liver of chronic alcoholics were investigated. Mean serum gamma-GTP activity in alcoholics was 542.5 +/- 337.9 milliunits/ml, and that of patients with nonalcoholic liver disease was 34.3 +/- 22.6 milliunits/ml. Hepatic gamma-GTP activity in alcoholics was significantly increased compared to that in control patients (15.62 +/- 9.29 versus 4.04 +/- 2.67 units/g of liver; p less than 0.001). A significant correlation was observed between hepatic and serum gamma-GTP activity. Light microscopically, a marked gamma-GTP activity was found in the bile canaliculi and a diffuse activity in the cytoplasm in alcoholic livers. By contrast, in the livers of nonalcoholic patients, only slight activity was observed in the bile canaliculi. The electron micrographs showed the enzyme was localized in the microvilli of both the bile canalicular and plasma membranes and the endoplasmic reticulum near the mitochondria in alcoholics. But a very low activity was demonstrated in the plasma membranes in the livers of nonalcoholic patients.

Bile Canaliculi↗