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Biomedical subjects

M Gnant

Publications and source records attributed to M Gnant.

63 records · Page 4Linked to original sources
PubMed1990

[Experiences and clinical results following 99 kidney transplantations with kidneys from relatives].

99 living related kidney transplantations were performed between January 1967 and December 1988. At the time of observation 4 of 94 organ donors had died; there was no correlation between unilateral nephrectomy and the patient's death. Intraoperative (2.9%) and postoperative (25%) complications did not result in severe physical consequences for the organ donors. Hypertension was found in 2 donors. There was no decrease in function of the remaining kidneys. The 3-year organ survival of the transplanted kidney was 60% with "conventional immunosuppression" and 93% with cyclosporin. No association was found between HLA DR-matching and graft survival. Rejection episodes occurred significantly more often in the HLA DR-mismatched grafts.

Adolescent↗
PubMed1989

[Professional organ procurement as a prerequisite for attaining the necessary transplantation frequency: experiences with organ distribution at the transplantation center in Vienna].

In the years 1965 to 1988 one or more organs were harvested for the purpose of transplantation from 649 brain dead organ donors reported to the Vienna transplantation centre. Based on a 1982 law regulating organ donation a large number of initiatives aiming at the improvement of the organ procurement system have taken place. In particular, the introduction of a decentralized donor guidance and organ retrieval system, a few information campaigns, as well as the introduction of full-time transplantation coordinators have significantly increased the number of organ donors. This development has made the Vienna transplantation centre one of the largest centres in Europe and has recently resulted in the achievement of a virtual balance between the increase of patients on the waiting list and the growth of the rate of transplantations performed. If this organ procurement policy is consistently continued in the years to come, there is a good chance of ensuring sufficient supply of organs for all patients on waiting lists, at least within the Viennese area.

Austria↗
PubMedDate not supplied

MHC-class-I expression in human breast cancer correlates with nuclear localization of the 90 kDa heat-shock-protein.

Breast cancer cells frequently exhibit a reduction in expression of major-histocompatibility-complex (MHC) class I proteins which blocks cytotoxic T-lymphocyte (CTL) mediated apoptosis. Recent studies indicate that the 90 kD heat-shock-protein (HSP90) plays a major role in the transfer of antigenic peptides to the MHC class I complex. HSP90 is a molecular chaperone which is involved in signal transduction and regulation of apoptosis. Since HSP90 is described to be elevated in breast cancer, its relationship with MHC class I expression was investigated. Using immunohistochemistry we analyzed the expression and localization of HSP90 and MHC class I in 17 human breast tumors. Positive correlation (p < 0.025) between strong nuclear staining for HSP90 and high MHC class I expression was observed. In tumors with reduced MHC class I expression, no nuclear localization of HSP90 was detectable. These findings lead to the hypothesis that tumor cells with high MHC class I expression and susceptibility to CTL action may escape apoptosis by a mechanism which involves increased nuclear HSP90.

Breast Neoplasms↗
PubMedDate not supplied

Different transendothelial migration behaviour pattern of blood monocytes derived from patients with benign and malignant diseases of the breast.

BACKGROUND: In this study we compared the expression of selected monocyte surface antigens with the potential to transmigrate through an endothelial layer before and after surgery from breast cancer patients (CA) and patients with benign disease of the breast (BE). MATERIALS AND METHODS: Transmigration capacity of mononuclear cells was determined after isolation by Ficoll density gradient, layered over human umbilical vein endothelial cells and cultured in a two chamber plate added with fMLP as a chemotactic stimulus. We determined monocyte phenotye (HLA-DR, FcgRI/CD64, CR1/CD11b and LFA-1/CD11a) and the phagocytosis of E. coli by flow cytometry. RESULTS: Before surgery blood monocytes had an equal expression of the measured surface antigens, but were different in regard to their interaction with endothelial cells. Monocytes derived from CA had a higher transmigration potency than those of BE. Moreover, the migration through the endothelial cell layer created different populations of monocytes. Surgical stress modified transmigrated monocytes of BE into the direction of monocytes from CA. Phagocytic capacity of peripheral blood monocytes from CA was significantly diminished and was further reduced after surgery when measured in transmigrated cells. CONCLUSION: Our study shows that monocytes from CA and BE can be discriminated in regard to their interaction with endothelial cells.

Adult↗
PubMedDate not supplied

Heat treatment of hepatocellular carcinoma cells: increased levels of heat shock proteins 70 and 90 correlate with cellular necrosis.

Immunotherapy, i.e. stimulation of the body's immune response against tumor cells, is a promising approach in cancer treatment. In this context, heat shock proteins (HSP) have been shown to function in tumor antigen chaperoning. HSP are evolutionarily conserved and show increased expression in response to chemical and physical stress. Two members of the HSP family, HSP 70 and 90, seem to further act as immunostimulating agents because of their possible involvement in tumor antigen presentation. We cultured the human hepatocellular carcinoma cell line HepG2 and investigated its HSP content under normal and hyperthermic conditions. Flow cytometry showed increased levels of HSP 70 and 90 after heat shock at 41.8 degrees C for 60 minutes, measured after a subsequent incubation time of five hours, as compared to untreated cells in vitro. We further observed a clear correlation between the HSP 70 and 90 levels and the necrotic cell subpopulation in heat shocked tumor cells. We conclude that HSP expression in HepG2 cells can be enhanced by heat shock treatment in vitro. We suggest that this mechanism can be exploited in increasing tumor immunogenicity.

Antibodies, Monoclonal↗