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Biomedical subjects

H Wolters

Publications and source records attributed to H Wolters.

40 records · Page 3Linked to original sources
PubMed1985

Effect of membrane fatty acid substitution and temperature on repair of sublethal damage in mammalian cells.

Repair of sublethal radiation damage (SLD) has been investigated as a function of temperature in mouse fibroblast LM cells with different membrane lipid composition. Rigidification or fluidization of the cellular membranes was accomplished by incorporation of myristic acid and arachidonic acid, respectively, in the phospholipids of the membranes. The SLD repair after radiation was essentially the same for the cells with the more rigid (saturated fatty acid) membranes and the cells with the more fluid (polyunsaturated fatty acid) membranes. This observation was made for repair at 37 degrees C as well as for repair at hypothermic temperatures. Incorporation of polyunsaturated fatty acid protected the cells against hypothermic death. These experiments demonstrate that although membranes are likely targets for cell killing by low temperature treatments, membrane lipids are probably not involved in the repair of sublethal radiation damage. It must be concluded that neither the degree of polyunsaturation of the lipids nor the degree of fluidity of the membrane is important for radiation-induced killing of mammalian cells.

Animals↗
PubMed1984

Radiosensitivity of normal and polyunsaturated fatty acid supplemented fibroblasts after depletion of glutathione.

Mouse fibroblast LM cells have been modified with respect to their phospholipid composition in all subcellular fractions, including the nuclear membrane. The content of polyunsaturated fatty acids (PUFA) was significantly increased but no difference in cell survival after X-irradiation could be observed between the normal and PUFA enriched cells. It is concluded that the radiosensitive PUFAs in the membranes are well protected against radiation damage. This protection of the PUFA cells could not be caused by vitamin E, because this membrane protector was not present in these fibroblasts. The content of glutathione (GSH) was about the same in the normal and the modified cells. Reduction of the cellular GSH content to less than 5 per cent of that for non-treated cells did not alter cellular survival after radiation of either normal or PUFA enriched cells under oxic or anoxic conditions. The radiosensitive lipids present in the membranes of the PUFA enriched cells proved to be vulnerable to radiation-induced lipid peroxidation when extracted from the cells and reconstituted into liposomes, indicating that the fatty acids per se are peroxidizable. It is concluded that the lipids in the membranes of mammalian cells are not the principal target in radiation-induced reproductive death, and that no generalization is permitted with respect to glutathione, as being the major hydrogen donating species in mammalian cells responsible for the repair of those target molecules responsible for cell survival after radiation.

Animals↗
PubMedDate not supplied

Gallbladder bile tumor marker quantification for detection of pancreato-biliary malignancies.

BACKGROUND: The pre-operative differentiation of tumors of the pancreas, Papilla of Vater and the biliary tract is still unsatisfactory. Tumor marker analysis of the pancreatic juice did not improve the pre-operative diagnosis by a great deal. METHODS: Bile from resected gallbladders of patients suffering from carcinomas of the pancreato-biliary system was analysed for CA 19-9, CEA, CA 72-4, CA 125 and AFP concentrations. The results were compared to patients suffering from acute cholecystitis, cholecystolithiasis as well as those suffering from benign tumors of the pancreato-biliary region. RESULTS: Extreme high CA 19-9 concentrations were found in bile. Evaluations of the tumor-antigens CA 19-9, CA 72-4 and CEA in gallbladder bile were superior to any serum and pancreatic juice examination with respect to sensitivity and specificity. Observed sensitivities amounted to 100% for patients suffering from bile duct carcinoma (CA 19-9) and papillary carcinoma (CEA) at a specificity of 100%. CA 19-9 showed a sensitivity of 76.5% for pancreatic carcinomas at a specificity of 96.4%. CA 19-9 showed significant differences for the local tumor burden and for the degree of lymph node metastasis. Examination of tumor antigens in the gallbladder results in a high degree of discrimination for malignant and benign lesions of the subhepatic pancreato-biliary system. CONCLUSIONS: CA 19-9 must follow a entero-hepatic circulation, since it showed raised bile concentrations (factor: 10(4)) compared to serum analysis. Analysis of CA 19-9, CEA and CA 72-4 gives an opportunity for improvement in the detection of cancers of the pancreato-biliary system. Since the clinical important differentiation of tumors of the head of the pancreas (carcinoma vs. pancreatitis) remains unclear, an improvement by bile analyses must be assumed.

Antigens, Tumor-Associated, Carbohydrate↗