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Biomedical subjects

R Viebahn

Publications and source records attributed to R Viebahn.

9 recordsLinked to original sources
PubMed1991

[Primary hepatocyte cultures as a model of experimental study of liver preservation].

Primary hepatocyte cultures have been used to evaluate data concerning hypoxic liver cell injury. To show the suitability of this method in liver preservation studies hepatocyte cultures were incubated under different conditions: warm normoxia (37 degrees C, pO2 greater than 70 mm Hg), warm hypoxia (37 degrees C, pO2 less than 0.1 mm Hg), cold normoxia (4 degrees C, pO2 greater than 70 mm Hg) and cold hypoxia (4 degrees C, pO2 less than 0.1 mm Hg). Incubations were performed in Euro Collins solution (EC), University of Wisconsin solution of Belzer (UW) and histidine ketoglutarat tryptophan solution of Bretschneider (HTK) as well as in Krebs Henseleit buffer (KH) for control incubations. During 12 h of incubation hepatocyte cultures under warm normoxia lost viability continuously in EC, UW and HTK while in KH they remained stable. Under warm normoxia all cultures lost 50% of their viability during 12 h of incubation while in cold normoxia loss of viability was mild but significant. Under cold anoxia which is the standard condition of liver preservation the cultured hepatocytes remained unchanged for 12 h in KH, UW and HTK, while in EC most of the cells were dead after 6 h. It is concluded that incubations of primary hepatocyte cultures under different pO2 and temperatures are well suited to contribute to liver preservation studies on a preclinical level and thus may help to save animal experiments.

Animals↗
PubMed1991

Differences in glycolytic capacity and hypoxia tolerance between hepatoma cells and hepatocytes.

Viability, glycolytic capacity and energy metabolism under anaerobic conditions were studied in the hepatoma cell lines HTC, FU5 and HepG2 and in rat and human hepatocytes using glucose and fructose as glycolytic precursors. During 6 hr of anaerobic incubation without additional substrate, viability decreased rapidly in FU5 and HTC cells, whereas viability of HepG2 cells was not significantly affected. In all tumor cells, 10 mmol/L glucose prevented hypoxic cell injury almost completely. Lactate formation from glucose was about five times higher than in hepatocytes under these circumstances. ATP content of the tumor cells remained almost constant under anaerobic conditions in the presence of glucose. Ten millimoles per liter of fructose diminished glycolysis in the hepatoma cells compared with glucose, ranging from 87% reduction in HTC cells to 43% reduction in HepG2 cells. Accordingly, ATP content decreased rapidly in the FU5 and slowly in the HepG2 cells. Viability was strongly diminished in the HTC and FU5 cells in the presence of fructose, whereas in the HepG2 cells no effect of fructose on viability was detectable. In contrast to the hepatoma cells, rat and human hepatocytes exhibited higher rates of anaerobic glycolysis in the presence of fructose and thus were able to maintain their viability under these conditions. These differences in glycolytic capacity, energy metabolism and hypoxia tolerance of hepatoma cells compared with hepatocytes may be used for the treatment of liver cancer by isolated liver perfusion and ex situ revision of the organ.

Adenosine Diphosphate↗
PubMed1990

[Pregnancy and labor following liver transplantation].

We report on pregnancy and delivery in a patient following hepatic transplantation. After an uneventful gestation at term, a child of normal body weight was born. To the best of our knowledge only 7 successful pregnancies following hepatic transplantation have been reported, one of them in the Federal Republic of Germany. Amongst the publications mentioned there are only two further reports on an immunosuppressive drug regimen utilising cyclosporine plus prednisolone. We stress the importance of the following items: peripartual immunosuppression, analgesia as well as the necessary control of the coagulation system.

Adult↗
PubMed1989

[Surgical therapy of liver and bile duct tumors].

The most effective surgical therapy of primary liver cancer (HCC) or proximal bile duct cancer (BDC) is radical resection, but only 20% of the patients will undergo this procedure, because the remaining patients in the advanced tumour-stage or cirrhosis can be given palliative treatment only (chemo-embolisation for HCC, endoscopic or percutaneous draining with or without iridium-after-loading for BDC) or a liver transplantation (LTX), though under immunosuppression an early recurrence of the tumour is frequent. One-year survival after resection because of HCC without cirrhosis is represented by a figure of 80%, whereas with cirrhosis it is 18%; 3 years after LTX, 26% of patients are alive. Three-year survival in untreated BDC is 24%, after resection of the hilum 42%, after LTX 40%.

Bile Duct Neoplasms↗
PubMed1985

Thymus carcinoid.

A carcinoid of the thymus was studied by light- and electron-microscopy, immunohistology and flow-cytometry. The tumor showed a ribbon- and festoon-like growth-pattern with foci of necrosis, invasion of vessels and infiltration of mediastinal lymph nodes. The cytoplasma of the tumor-cells contained neuroendocrine granula and immunohistochemistry of ACTH was positive. The tumor-cells were connected by desmosomes, correlating to a pre-keratin positive immunohistology. In flow-cytometry the tumor-cells showed a near haploid DNA aneuploidy which is an extremely rare finding in solid tumors and in the few cases described indicative for treatment resistance.

Carcinoid Tumor↗