Biomedical subjects

M M Pich

Publications and source records attributed to M M Pich.

4 recordsLinked to original sources

PubMed1999

Protective effect of exogenous coenzyme Q in rats subjected to partial hepatic ischemia and reperfusion.

In a surgical model of liver ischemia lipid peroxidation occurs, as shown by increase of lipid peroxidation end products, endogenous CoQ9 is oxidized and mitochondrial respiration is lowered; however, pre-treatment of the rats by i.p. injection of CoQ10 for 14 days normalizes the above parameters, presumably by way of the observed high extent of reduction of the incorporated quinone; moreover, liver homogenates of the CoQ10-treated rats are more resistant than those of non-treated rats to oxidative stress induced by an azido free radical initiator. This preliminary study suggests that CoQ10 pre-treatment can be of beneficial effect against oxidative damage during liver surgery transplantation.

Amidines↗

PubMed1998

Mitochondrial DNA in platelets from aged subjects.

This study aimed to assess platelets as a possible model for screening the accumulation of mitochondrial DNA mutations, particularly during normal ageing. For this purpose we isolated platelets from young and old donors selected by lack of systemic and haematological diseases. We studied the accumulation of a particular deletion (4977-bp deletion) that usually accumulates in an age-related manner in different post-mitotic tissues, such as brain, heart and skeletal muscle, and in some non-post-mitotic tissues (skin, liver). Using different primers, we failed to detect this particular species of deletion in platelets both from young and old individuals. However, we cannot exclude the presence of other species of deletions or point mutations affecting the mitochondrial DNA in platelets during the aging process.

Adolescent↗

PubMed1997

Mitochondrial complex I defects in aging.

According to the 'mitochondrial theory of aging' it is expected that the activity of NADH Coenzyme Q reductase (Complex I) would be most severely affected among mitochondrial enzymes, since mitochondrial DNA encodes for 7 subunits of this enzyme. Being these subunits the site of binding of the acceptor substrate (Coenzyme Q) and of most inhibitors of the enzyme, it is also expected that subtle kinetic changes of quinone affinity and enzyme inhibition could develop in aging before an overall loss of activity would be observed. The overall activity of Complex I was decreased in several tissues from aged rats, nevertheless it was found that direct assay of Complex I using artificial quinone acceptors may underevaluate the enzyme activity. The most acceptable results could be obtained by applying the 'pool equation' to calculate Complex I activity from aerobic NADH oxidation; using this method it was found that the decrease in Complex I activity in mitochondria from old animals was greater than the activity calculated by direct assay of NADH Coenzyme Q reductase. A decrease of NADH oxidation and its rotenone sensitivity was observed in nonsynaptic mitochondria, but not in synaptic 'light' and 'heavy' mitochondria of brain cortex from aged rats. In a study of Complex I activity in human platelet membranes we found that the enzyme activity was unchanged but the titre for half-inhibition by rotenone was significantly increased in aged individuals and proposed this change as a suitable biomarker of aging and age-related diseases.

Adult↗

PubMed1996

Coenzyme Q depletion in rat plasma after partial hepatectomy.

Coenzyme Q content was monitored in blood plasma and regenerating liver mitochondria of hepatectomized rats, using as controls either sham-operated or non-operated animals. Mitochondrial CoQ9 content increased in sham-operated rats, whilst it was significantly lower in hepatectomized in comparison with non-operated animals at all considered times. On the other hand plasma CoQ9 levels dramatically decreased in hepatectomized animals, while strongly increased in sham-operated in comparison with non-operated rats. The quinone decrease in hepatectomized animals is likely to be due to the attainment of a rate-limiting step in CoQ biosynthesis.

Animals↗