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D Gu

Publications and source records attributed to D Gu.

59 records · Page 4Linked to original sources
PubMed1993

Epithelial cell proliferation and islet neogenesis in IFN-g transgenic mice.

We have identified a model system for the study of pancreatic islet development and regeneration in transgenic mice bearing the interferon-gamma (IFN-g) gene expressed in the pancreatic islets. Previous studies showed that the locally produced IFN-g causes lymphocyte infiltration and islet cell destruction. Here we demonstrate that new islet cells are formed continuously from duct cells as evidenced by (1) the dramatic proliferation of duct cells, (2) the appearance of primitive cells and (3) their subsequent differentiation to endocrine cells. The IFN-g induced islet neogenesis is similar to embryonic islet morphogenesis and offers a model system for studying factors modulating islet development. Additionally, the duct cells occasionally transdifferentiate to gastrointestinal-like cell types and hepatocytes. These results underscore the lymphokine's ability to initiate a complex 'transdifferentiation' pathway, providing a window for understanding lineage interrelationships within a terminally differentiated structure.

Animals↗
PubMed1993

[Research on anti-idiotypic antibodies to bovine abortus].

Based on the establishment of McAbs to a local Brucella strain S85A, the McAb A7 was selected and tested as a protective one. Using A7 to immunize rabbits, we got high titer anti-idiotypic antibodies which were then proved to possess internal image by competitive inhibiting ELISA and catch blocking ELISA. The anti-idiotypic antibodies were then purified and mixed with glycerin to immunize guinea pigs and mice. The results showed that: immunized guinea pigs and mice had produced certain titer antibodies to Brucella. 79.2% of immunized guinea pigs had been protected from the challenge of 544A 4 months later from primary immunization. The number of T ANAE+ in peripheral blood of immunized mice had increased significantly compared to controls. These results suggest that the anti-idiotypic antibodies not only possess the antigen internal image but have the available immunogenicity stimulate animals producing Ab3 and make them get free from the infection.

Animals↗
PubMed1992

Regeneration of pancreatic endocrine cells in interferon-gamma transgenic mice.

We have shown that the pancreatic duct cells of IFN-gamma mouse are actively multiplying and that many duct cells differentiate to become endocrine cells. This islet regenerating process closely parallels the islet development during normal organogenesis in the fetus and offers a model for studying the cell lineage relationships of islet cells. The subject has received wide interest and intensive research in recent years. One of the noteworthy results of this study is the finding that duct cells retain the ability to proliferate and to differentiate into islet cells. Under normal conditions, duct cells do not continue to multiply or to differentiate. The results suggest that in the transgenic mice, the progenitor cells of embryonic multipotential duct cells transform into adult cells, but in the presence of appropriate signals or stimuli can resume their multipotential property. The appearance of hepatocytes indicates that while the cell proliferation observed largely results in endocrine cells, other differentiation pathways are occasionally possible. We also detect a few large cells containing albumin and alpha-fetoprotein in the periductal area. Pancreatic hepatocytes have also been observed in the rat after recovery from copper deficiency diet. Thus, the regeneration of islet cells in transgenic mice provides a model system for the study of factors modulating the growth pattern as well as the differentiation pathway.

Animals↗
PubMed1992

Diagnostic exploration of enlarged peripheral nerves in suspected cases of leprosy. An analysis of 55 cases.

In 55 cases presenting with enlarged peripheral nerves without any skin lesions, a rice grain-sized biopsy of the nerve lesion was taken for histopathological examination. As a result definitive diagnoses could be established: leprosy was diagnosed in 32 cases. In 23 cases the cause of nerve enlargement was not leprosy: post-traumatic neuritis 9, cysts 5, hypertrophic neuritis 3, nonspecific 4, neurofibroma 1, and amyloidosis 1. In all of these cases there was a deficit of the nerve function and postoperatively there were no complications. The authors, as a result of this experience, believe that surgical exploration and biopsy is a harmless diagnostic tool for establishing a definitive diagnosis of leprosy in cases presenting with enlarged peripheral nerves without any skin lesions. In 23 out of 55 such cases the nerve enlargement was proved to be other causes than leprosy.

Adolescent↗