Respiratory chain complexes and membrane fatty acids composition in rat testis mitochondria throughout development and ageing

Throughout the maturation of germ cells, a morphological, biochemical and functional differentiation of mitochondria has been shown to occur. Ageing is known to cause changes involved in energy metabolism. These changes have been related to molecular and functional alterations in the properties of biological membranes. Variations in membrane lipid composition and lipid-protein interactions occur with ageing in several tissues. The present paper describes the relationship between these membrane alterations and the activities of lipid-dependent enzymes of isolated testis mitochondria in rats of from 10 days of age to 24 months. The specific activities of these enzymes are lower in preparations from adult and aged rats as compared to those from young rats. Temperature breaks of Arrhenius plots show age-dependent shifts to higher temperatures for the NADH-dehydrogenase, succinate-dehydrogenase, cytochrome c oxidase, and ATPase in senescent animals. Analysis of the membrane fatty acid composition reveals a distinct age-dependent fall in the content of polyunsaturated fatty acids accompanied by an increase in the proportion of saturated fatty acids and a decrease in polyunsaturated fatty acid percentage. The results suggest that during spermatogenesis and the ageing process some changes in the composition of the fatty acids in the surrounding membrane affect the protein-lipid interactions, producing a decrease in mitochondrial enzyme activities.     

Ischemia-reperfusion injury during experimental heart transplantation. Evaluation of trimetazidine's cytoprotective effect

INTRODUCTION AND OBJECTIVES: The objectives of this study were to analyze the ischemia-reperfusion injury due to free radicals that occurs during heart transplantation and to determine the potential cytoprotective effect of trimetazidine. MATERIAL AND METHOD: A total of 21 orthotopic heart transplantations were performed in pigs. We divided the experimental animals into 2 groups: in group A (n=11),standard myocardial protection was used; in group B (n=10), trimetazidine was added to the cardioplegic solution used to protect the donor heart and to the solution administered to the recipient prior to release of the aortic clamp (trimetazidine, 10(-5) mol/L), and recipients were pretreated with trimetazidine, 2.5 mg/kg. Blood samples were taken from the recipients coronary sinus at three times: at baseline, during ischemia, and during reperfusion. We measured the levels of malondialdehyde, a marker of lipid peroxidation, and of several antioxidants: glutathione peroxidase, glutathione reductase, superoxide dismutase, alpha-tocopherol, and retinol. The total antioxidant status was also determined. RESULTS: Malondialdehyde production and enzymatic antioxidant activity rose during ischemia and reperfusion, while the retinol level decreased. The increases in malondialdehyde level and glutathione peroxidase activity that occurred between baseline and reperfusion were significantly higher in group A. CONCLUSIONS. The degree of lipid peroxidation and the level of activity of intracellular antioxidant mechanisms increased progressively throughout transplantation. Trimetazidine had a cytoprotective effect. It ameliorated free radical-induced reperfusion injury and modified the response pattern of several defense mechanisms.     

Differences in chromosome susceptibility to aneuploidy and survival to first trimester

The purpose of this study was to find specific rates of aneuploidy in cleavage-stage embryos compared with first trimester data and to evaluate post-zygotic selection against aneuploidy. A total of 2058 embryos were analysed by flurorescence in-situ hybridization (FISH), and specific aneuploidy rates were obtained for 14 chromosomes. Data from morphologically abnormal embryos could be pooled with data from preimplantation genetic diagnosis (PGD) cycles because it was observed that they had similar rates of aneuploidy; thus, for the purpose of studying aneuploidy they could be, and were, pooled. Specific chromosome aneuploidy rates were not related to morphology or development of the embryos. The average maternal age of patients with aneuploid embryos was significantly higher than the overall analysed population. Monosomy appeared more commonly than trisomy. The chromosomes most frequently involved in aneuploidy were (in order) 22, 16, 21 and 15. When compared with first trimester pregnancy data, aneuploidies detected at cleavage stage seem to die in excess of 90% before reaching first trimester, with the exception of chromosome 16 and gonosomes (76% and 14% respectively). Differences in chromosome-specific aneuploidy rates at first trimester conceptions are probably produced by different chromosome-specific aneuploidy rates at cleavage stage and different survival rates to first trimester.     

Predictability of preimplantation genetic diagnosis of aneuploidy and translocations on prospective attempts

The aim of this study was to determine if the outcomes of aneuploidy and translocation testing by preimplantation genetic diagnosis (PGD) at the 8-cell stage have a predictive value for new genetic diagnosis cycles. In total, 83 cycles (39 patients) undergoing PGD of translocations and 378 cycles (176 patients) of aneuploidy were included. Predictability, defined as having similar rate (+/-20%) of euploid embryos in the first and successive cycles, was found in 66% of patients undergoing aneuploidy testing. Predictability was found significantly more often in patients undergoing PGD of translocations (90%, P = 0.006). In addition, patients with 0, <30 or > or =30% euploid embryos in the first cycle were compared and groups 0 and <30% had significantly fewer euploid embryos in the second cycle (22-26%) than those of the group with > or =30% (37%) (P < 0.05). Patients who did not become pregnant after the first attempt were stimulated more aggressively than those becoming pregnant, producing significantly more embryos in the second than in the first cycle (P < 0.001). Therefore, correlation between euploidy rate and pregnancy rate could not be assessed objectively between cycles. In conclusion, the PGD results of a first cycle can predict the results of the second cycle, but this is likely to be of more value when the condition investigated is translocation rather than aneuploidy. The chance of pregnancy is usually related to the number of euploid embryos.     

Metastasis in renal graft of primary renal adenocarcinoma

Acquired cystic renal disease (A.C.R.D.) is a risk factor for the development of renal carcinoma in the patient's own kidney after renal transplant (R.T.), development of a primitive tumor in the renal graft is infrequent, but the presence of metastasis of an epithelial tumor is very rare. This is the second case reported in the literature of metastasis of an epithelial tumor in the renal graft and the first case described of renal cell carcinoma metastasis (R.C.C.) in the renal graft. This paper describes the case of a patient with a normally functioning renal transplant and A.C.R.D. who develops RCC in his own kidney, with metastasis in the renal graft.     

Peripapillary glial cells in the chick retina: A special glial cell type expressing astrocyte, radial glia, neuron, and oligodendrocyte markers throughout development

Peripapillary glial cells of the chick are a special type of glia, not only because of their position, forming a boundary between the retina on one side and the optic nerve head (ONH) and the pecten on the other, but also because although they have the same orientation and similar shape as the retinal Müller cell (a type of radial glia) and express common markers for these cells and astrocytes, they do not express glutamine synthetase (GS) or carbonic anhydrase C (CA-C), enzymes intensely expressed by Müller cells and astrocytes. In this study, we present further molecular characterization of these cells, using immunohistochemistry techniques. We show that peripapillary glial cells express a novel neuron antigen, 3BA8, that in the adult retina is located only in one neuron type (the amacrine cell) and in the inner plexiform layer (IPL). They also express an antigen specific to myelin and oligodendrocytes, MOSP, and a glial antigen, 3CB2, expressed by radial glia and astrocytes throughout the CNS. The study of the developmental expression of these three antigens in the peripapillary glial cell territory shows different spatiotemporal labeling patterns: 3CB2 and 3BA8 are expressed much earlier (embryonic days E3 and E5, respectively) than MOSP (E12), and during a developmental window (E6-E10) 3BA8 labels the peripapillary glial cells intensely and does not label the ONH or the optic nerve (ON), which are labeled later. The expression of 3CB2 is much more intense in the peripapillary glial cells than in Müller cells from early stages of development up to E16, and the expression of MOSP starts earlier in the peripapillary glial cells than in the Müller cells and is maintained with much higher intensity in the peripapillary glial cells throughout development. These findings show that Müller and peripapillary glial cells follow independent courses of differentiation, which together with the fact that the peripapillary glial cells express molecules typical of neurons, oligodendrocytes, radial glia, and astrocytes are evidence that peripapillary glial cells are a unique type of glia in the CNS.