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Biomedical subjects

S Stocker

Publications and source records attributed to S Stocker.

50 records · Page 3Linked to original sources
PubMed1982

[Detection of collagen by immunofluorescence during development of Xenopus (Xenopus laevis Daud.)].

Appearance of the different collagen types was studied during the clawed toad development from hatching to metamorphosis, using indirect immunofluorescence techniques. Type-like IV collagen of basement membranes was first seen in the notochord streath. Type I, type II were detected at the same time, followed by type III. Developmental sequence and distribution of the four collagen types indicate the different stages of organogenesis.

Animals↗
PubMed1981

Hepatic eosinophil granulocytopoiesis in murine experimental Schistosomiasis mansoni.

In livers of mice with acute schistosomiasis eosinophil granulocytopoietic folliculi are described. Exogen stem cells were observed in hepatic sinusoids. Their proliferation and progressive maturation are described. Specific reactions to the presence of worms and their eggs, and Kupffer-cell stimulation and hyperplasia are considered to be responsible for this extramedullary granulocytopoiesis.

Animals↗
PubMed1980

The implantation of sepharose beads in mouse livers as an aid in the study of hepatic schistosomal fibrosis.

An experimental model of schistosomal portal fibrosis is described. Sepharose beads the size of schistosome eggs, loaded or not with soluble egg antigen (SEA) from Schistosoma mansoni, are injected into the coecal vein of C3H/Sn mice and become embolized in the liver. Only SEA-coated beads evoke a granulomatous reaction; this is enhanced by simultaneous priming of the mice with spleen cells from Schistosoma mansoni-infected syngeneic animals. The fibrosis, which ensues around the beads, is stable and is much more evident after priming. Preliminary collagen tissue immunotyping reveals the presence of collagen deposits of types I and III collagen. Type IV collagen remains unchanged in the portal tracts. The model appears to be well suited for studies of the pathogenesis of portal fibrosis.

Animals↗
PubMed1980

[Corneoscleral trabecular collagen. Ultrastructural changes and immunotyping in chronic and cortisone-induced glaucoma].

Ultrastructural changes in connective matrix of corneoscleral trabeculum in primary open-angle glaucoma and corticosteroid-induced glaucoma are described. Four forms of collagen fibers were observed: typical, hyper-, segmented fibers and cross-banded collagen. Light and electron microscopy, using antibodies against collagen types, demonstrates the presence of type I collagen widely distributed in trabecular connective matrix and type III collagen in perivascular zones. Type IV collagen is located on basal membranes on endothelial lamina. In glaucomatous disease, the ultrastructural aspect of connective matrix reflects a continuous remodelling process associating fibrolysis and fibrogenesis.

Adolescent↗
PubMed1977

[Effects of alpha-amanitin on the development of Xenopus (Xenopus laevis Daud.) heart in vitro].

The differentiation of Xenopus heart is studied in vitro, in the presence of alpha-amanitin. The results obtained depend on the concentration of the inhibitor, the length of treatment and the stage of primordium. The mRNA pool assures the differentiation of explants, removed from young stages, for 12 hours. This time is half for the primordia removed from stages greater than 3,5 mm.

Amanitins↗
PubMed1976

[Influence of actinomycin D on Xenopus heart differentiation in organ culture].

The cardiac differentiation of the African clawed Toad was studied in culture with Actinomycin D. In terms of drug amounts used and the duration of treatment, a limit coefficient was defined, beyond which the heart did not again differentiate. The results were interpreted by the existence of a threshold in the inhibition of ARNr synthesis, whose total turn-over seemed to be 24 hours.

Animals↗
PubMedDate not supplied

[Dermal aging. Immunofluorescence study of collagens I and III and fibronectin].

In this study the authors have studied 10 young subjects and 10 old subjects. The biopsies are examined by light microscopy, and by immunofluorescence techniques with specific antibodies against collagen I, III and fibronectin. In this last case the authors used also immunoelectron microscopy with peroxidase labeling and immunofluorescence techniques in fibroblasts cultures. The results showed that there was no difference in collagen localization in young and old subjects. But the fibronectin was found decreased in papillary dermis of old subjects. These results are confirmed in culture, where the fibrillar extracellular fibronectin was abundant in culture of young subjects and very poor in old subjects. The role of fibronectin will be very important in ageing, its decrease will explain the morphological modifications of dermal connective tissue with age.

Adult↗