Biomedical subjects

David Meierhofer

Publications and source records attributed to David Meierhofer.

2 recordsLinked to original sources

PubMed2004

Decrease of mitochondrial DNA content and energy metabolism in renal cell carcinoma.

To elucidate the relationship between tumor genesis and the mitochondrial energy metabolism in renal neoplasms, we studied three individual enzyme activities of the oxidative phosphorylation, two components of the Krebs cycle and the mitochondrial DNA content of renal carcinomas including 29 conventional, five papillary, two unclassified carcinomas with sarcomatoid features and one collecting duct carcinoma. A significant reduction of all mitochondrial enzyme activities including complex V, as well as of the mitochondrial DNA content was detected in 34 of 37 renal carcinoma tissues as compared with control kidney. Mitochondrial enzyme activities and mitochondrial DNA levels were not statistically different between the conventional, papillary and unclassified sarcomatoid type of renal carcinoma and did not correlate with tumour grade, metastasis, ploidy and proliferative activity as determined by Ki-67 staining. Taken together, our data indicate that a co-ordinated down-regulation of all components necessary for mitochondrial energy metabolism occurs in most renal carcinomas as an early event in carcinoma formation, which does not change with progression of the disease.

Adult↗

PubMed2002

Severe depletion of mitochondrial DNA in spinal muscular atrophy.

Spinal muscular atrophy (SMA) is a neuromuscular disorder in childhood leading to a dramatic loss of muscle strength. Functional investigations with high-resolution polarography and enzyme measurements of the respiratory chain revealed lowered activities in muscle tissue of SMA patients. To gain a better understanding of this low energy supply we analyzed the amount of mitochondrial DNA (mtDNA) in skeletal muscle of 20 unrelated children with genetically proven SMA and 31 controls. Quantitative Southern blot analysis revealed a severe and homogeneous decrease in the content of muscle mtDNA in relation to nuclear DNA in SMA patients (90.3+/-7.8%), whereas by immunofluorescence no decrease in the number of mitochondria was detected. In addition, a two- to threefold reduction of the nuclear-encoded complex II (succinate dehydrogenase) activity was detected in SMA muscle tissue. Western blot analysis showed a significant reduction of both mitochondrial- and nuclear-encoded cytochrome c oxidase subunits. Our results indicate that mtDNA depletion in SMA is a consequence of severe atrophy, and has to be differentiated by measurement of complex II from an isolated reduction of mtDNA as found in patients with mitochondriocytopathies and the so-called mtDNA depletion syndrome.

Adolescent↗