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Biomedical subjects

R M Hoffmann

Publications and source records attributed to R M Hoffmann.

78 records · Page 5Linked to original sources
PubMed1980

Toxicity of oxygen to mitochondrial respiratory activity in hypothermically perfused canine kidneys.

Respiratory activity of kidney cortex homogenates was measured after various periods of hypothermic pulsatile preservation of dog kidneys with cryoprecipitated plasma. There was a progressive loss of pyruvate plus malate-stimulated respiration (30 to 40% at 3 days and 70 to 80% at 5 days) and succinate-stimulated respiration (15 to 20% at 3 days and 50 to 60% at 5 days). Perfusion under conditions of low pO2 (30 to 40 mm Hg) or with inhibitors of the toxic effects of hyperbaric oxygen (CO2+ Mn2+) preserved homogenate respiratory activity better than with normal pO2 (150 mm Hg) or high pO2 (300 mm Hg). The results suggest that oxygen toxicity (lipid peroxidation) and the progressive loss of respiration in homogenates may be limiting factors in obtaining long-term preservation.

Adenosine Diphosphate↗
PubMedDate not supplied

Differential expression of MHC class II subregion products on bile duct epithelial cells and hepatocytes in patients with primary biliary cirrhosis.

To study the expression of MHC Class II subregion gene products on biliary epithelial cells in primary biliary cirrhosis, frozen sections from liver biopsies of 15 patients with primary biliary cirrhosis were studied immunohistochemically using HLA-D subregion specific monoclonal antibodies L243 (HLA-DR), Leu10 (HLA-DQ) and B7/21 (HLA-DP). Patients with early stages of primary biliary cirrhosis showed expression of HLA-DP, HLA-DR and HLA-DQ subregion gene products on bile duct epithelial cells. In advanced stages of disease, no MHC Class II antigens or only HLA-DR and HLA-DP were expressed on bile duct cells. While normal hepatocytes did not express detectable amounts of MHC Class II antigens, hepatocytes from liver biopsies of four patients with primary biliary cirrhosis showed a distinct staining exclusively with monoclonal antibodies specific for HLA-DR. The expression of MHC Class II antigens on parenchymal cells was independent of a lymphocytic infiltration into the tissue. This study demonstrates that bile ductular cells, but not hepatocytes, express a full set of MHC Class II molecules at least during the early stages of primary biliary cirrhosis. We propose, therefore, that the expression of both HLA-DR and HLA-DQ subregion products on bile duct epithelial cells may be a necessary, although not sufficient, condition for the initiation of an autoimmune process leading to the destruction of intrahepatic bile ducts in primary biliary cirrhosis.

Antibodies, Monoclonal↗
PubMedDate not supplied

Simultaneous pancreas-kidney (SPK) transplantation from controlled non-heart-beating donors (NHBDs).

From January 1993 through June 1999, 18 simultaneous pancreas-kidney transplants (SPKs) were performed from controlled non-heart-beating donors (NHBDs) and 339 SPKs were performed from heart-beating donors (HBDs). No difference in donor characteristics was noted except for warm ischemic time, which was 14.8 min (range 4-46 min) for NHBDs. Following transplantation, no difference in pancreatic function was noted; however, a higher rate of enteric conversions was seen in pancreas transplants from NHBDs (32% vs. 13%; p < 0.01). Hemodialysis for acute tubular necrosis (ATN) was higher in kidney transplants from NHBDs (22.2% vs. 4.1%; p = 0.009) as was discharge serum creatinine (1.7 mg/dl vs. 1.5 mg/dl; p < 0.05). Also, the number of patients remaining rejection free was lower for NHBDs and approached significance (33.3% vs. 50.1%; p = 0.07). However, no difference in patient survival (100% vs. 95.4%) or pancreatic (87.4% vs. 86.5%) and renal (86.3% vs. 86.3%) allograft survival was noted during the study period. Our results indicate that SPK transplantation from controlled NHBDs is a viable method for increasing the number of pancreas and kidney transplants available for transplantation.

Adult↗