[Alzheimer's disease cerebro-spinal fluid biomarkers: A clinical research tool sometimes useful in daily clinical practice of memory clinics for the diagnosis of complex cases]. / Les biomarqueurs du liquide cérébro-spinal dans la maladie d'Alzheimer : un outil de recherche utile dans la pratique clinique courante des consultations mémoire pour les cas complexes.

The role of biomarkers in clinical research was recently highlighted in the new criteria for the diagnosis of Alzheimer's disease. Cerebro-spinal fluid (CSF) biomarkers (total Tau protein, threonine 181 phosphorylated Tau protein and amyloid Aß1-42 peptide) are associated with cerebral neuropathological lesions observed in Alzheimer's disease (neuronal death, neurofibrillary tangle with abnormal Tau deposits and amyloid plaque). Aß1-40 amyloid peptide dosage helps to interpret Aß1-42 results. As suggested in the latest international criteria and the French HAS (Haute Autorité de santé) recommendations, using theses CSF biomarkers should not be systematic but sometimes could be performed to improve confidence about the diagnostic of Alzheimer's disease in young subjects or in complex clinical situations. Future biomarkers actually in development will additionally help in diagnostic process (differential diagnosis) and in prognostic evaluation of neurodegenerative diseases.

Training-induced anti-atherosclerotic effects are associated with increased vascular PPARgamma expression in apolipoprotein E-deficient mice.

AIM: Physical exercise prevents cardiovascular risk and atherosclerosis lesions. However, the molecular aspects are still unknown. Vascular peroxisome proliferator-activated receptors (PPARs) exert anti-atherogenic effects. The aim of this study was to determine whether exercise-induced anti-atherosclerotic effect is associated with change in PPARs vascular expression in apolipoprotein E-deficient (ApoE(-/-) ) mice. METHODS: Male ApoE(-/-) mice were fed with a high-fat diet and randomized into two groups: one trained group undergoing swimming training for 3 months and one sedentary group. Sedentary and trained C57BL/6J mice were used as control. mRNA of PPAR-α, PPAR-ß/δ and PPAR-γ was measured in aorta by quantitative PCR. mRNA of pro- (TNF-α, IL-1ß) and anti-inflammatory (IL-10, IL-1Ra) cytokines was also measured. RESULTS: Atherosclerotic lesion size was significantly reduced in trained ApoE(-/-) mice compared to sedentary ones. In contrast, reduction of atherosclerotic lesion size was not observed in trained ApoE(-/-) mice supplied with BADGE, an antagonist of PPAR-γ. Exercise training significantly increased PPAR-γ expression in aorta. PPAR-γ expression was inversely correlated with the atherosclerotic plaque area. Aortic PPAR-α and PPAR-ß/δ mRNA expressions were not changed in response to exercise training. Atherosclerosis increased the aortic mRNA expression of TNF-α, IL-1ß, IL-10 and IL-1Ra. Exercise training decreased aortic IL-1ß mRNA expression in ApoE(-/-) mice, but did not change expression of TNF-α, IL-10 and IL-1Ra. IL-1ß mRNA expression was also significantly lower in atherosclerosis lesions from trained ApoE(-/-) compared with those from sedentary ones. CONCLUSIONS: Exercise training increases vascular PPAR-γ expression in ApoE(-/-) mice that could potentially underlie training-related beneficial effects on atherosclerosis.

Role of temperature-independent lipoplex-cell membrane interactions in the efficiency boost of multicomponent lipoplexes.

Multicomponent lipoplexes have recently emerged as especially promising transfection candidates, as they are from 10 to 100 times more efficient than binary complexes usually employed for gene delivery purposes. Previously, we investigated a number of chemical-physical properties of DNA-lipid complexes that were proposed to affect transfection efficiency (TE) of lipoplexes, such as nanoscale structure, size, surface potential, DNA-protection ability and DNA release from complexes upon interaction with cellular lipids. Although some minor differences between multicomponent and binary lipoplexes were found, they did not correlate clearly with efficiency. Instead, here we show that a marked difference between the cell internalization mechanism of binary and multicomponent lipoplexes does exist. Multicomponent lipoplexes significantly transfect cells at 4 °C, when endocytosis does not take place suggesting that they can enter cells via a temperature-independent mechanism. Confocal fluorescence microscopy experiments showed the existence of a correlation between endosomal escape and TE. Multicomponent lipoplexes exhibited a distinctive ability of endosomal escape and release DNA into the nucleus, whereas, poorly efficient binary lipoplexes exhibited minor, if any, endosomal rupture ability and remained confined in perinuclear late endosomes. Stopped-flow mixing measurements showed that the fusion rates of multicomponent cationic liposomes with anionic vesicles, used as model systems of cell membranes, were definitely shorter than those of binary liposomes. As either lipoplex uptake and endosomal escape involve fusion between lipoplex and cellular membranes, we suggest that a mechanism of lipoplex-cellular membrane interaction, driven by lipid mixing between cationic and anionic cellular lipids, does explain the TE boost of multicomponent lipoplexes.

High circulating levels of 7beta- and 7alpha-hydroxycholesterol and presence of apoptotic and oxidative markers in arterial lesions of normocholesterolemic atherosclerotic patients undergoing endarterectomy.

In previous investigations, we found that 7beta-hydroxycholesterol had potent pro-apoptotic, and pro-oxidative properties. So, we asked whether the circulating level of this oxysterol was enhanced in atherosclerotic patients undergoing endarterectomy of the superficial femoral artery. To this end, 7beta-hydroxycholesterol serum concentrations were determined and compared with common lipid parameters in atherosclerotic patients, and in healthy subjects. 7alpha-hydroxycholesterol was simultaneously measured to evaluate the reliability of the method used for oxysterol analysis. On normal and atherosclerotic arterial fragments from patients, markers of oxidation (4-hydroxynonenal (4-HNE) adducts), and apoptosis (activated caspase-3; condensed/fragmented nuclei) were studied. Interestingly, high serum concentrations of 7beta- and 7alpha-hydroxycholesterol were found in normocholesterolemic atherosclerotic patients. However, in statin-treated patients, the circulating levels of 7beta- and 7alpha-hydroxycholesterol tend towards normal values. Therefore, 7beta- as well as 7alpha-hydroxycholesterol could be more appropriate markers of lipid metabolism disorders than cholesterol or LDL in normocholesterolemic patients with atherosclerosis of the lower limbs, and statins could normalize their serum concentrations. At the arterial level, apoptotic cells were mainly identified in low grade lesions and no statin effects were found on oxidation and apoptosis.

Caracterizacion genetica y morfologica de las poblaciones de Cyprinodon dear-borni (Atherinomorpha: Cyprinodontidae) en Chacopata y Laguna de los Patos, Venezuela / Genetic and morphological characteristics of the populations of Cyprinodon dearborni (Atherinomorpha: Cyprinodontidae) in Chacopata and Laguna de los Patos, Venezuela

Two populations of the fish Cyprinodon dearborni were compared, one from Laguna de Chacopata and the other from Laguna de los Patos, Cumana, Venezuela. The morphometric method of the Box Truss was used; the organisms were photographed with a digital camera. In the images 18 measures were made to each organism, with the MOCHA 1.2 program. The tendencies of morphologic variation among populations were analyzed by main components using STATGRAPHICS 2.0 and SHEAR programs. The first four main components in males and females explained 88 of the total variation. The components two, three and four separate the two populations based on the body form of the animals. For the electrophoretic study, 13 enzymatic systems were analyzed in starch gels. The variation and genetic distance were calculated with the program GENES 2.0. Differences were observed in the systems G6PDH, GPI; ES and GLUD, that which can be used as isoenzimatic markers. Genetic diversity of Chacopata (H = 0.086, p = 0.079) was higher than in Laguna de los Patos (H = 0.029, p = 0.028), but both are within the average in populations of fish. The two populations presented a Nei distance of 0.058. The genetic and morphologic differentiation suggests an incipient process of separation whose causes could be the ecological conditions of their habitat, or processes of vicariant speciation.

[Genetic and morphological characteristics of the populations of Cyprinodon dearborni (Atherinomorpha: Cyprinodontidae) in Chacopata and Laguna de los Patos, Venezuela]. / Caracterización genética y morfológica de las poblaciones de Cyprinodon dear-borni (Atherinomorpha: Cyprinodontidae) en Chacopata y Laguna de los Patos, Venezuela.

Two populations of the fish Cyprinodon dearborni were compared, one from Laguna de Chacopata and the other from Laguna de los Patos, Cumaná, Venezuela. The morphometric method of the Box Truss was used; the organisms were photographed with a digital camera. In the images 18 measures were made to each organism, with the MOCHA 1.2 program. The tendencies of morphologic variation among populations were analyzed by main components using STATGRAPHICS 2.0 and SHEAR programs. The first four main components in males and females explained 88% of the total variation. The components two, three and four separate the two populations based on the body form of the animals. For the electrophoretic study, 13 enzymatic systems were analyzed in starch gels. The variation and genetic distance were calculated with the program GENES 2.0. Differences were observed in the systems G6PDH, GPI; ES and GLUD, that which can be used as isoenzimatic markers. Genetic diversity of Chacopata (H = 0.086, p = 0.079) was higher than in Laguna de los Patos (H = 0.029, p = 0.028), but both are within the average in populations of fish. The two populations presented a Nei distance of 0.058. The genetic and morphologic differentiation suggests an incipient process of separation whose causes could be the ecological conditions of their habitat, or processes of vicariant speciation.

Polymorphisms of octopine dehydrogenase (Odh) in mollusks and implications for the neutralism-selectionism hypothesis

Octopine dehydrogenase (Odh) was examined in several species of bivalves and gastropods and complemented with bibliographic data, to assess the controversy between neutralism and selectionism in explaining the maintenance of genetic variation in natural populations. This debate was the center of the molecular evolution and population genetic research in the 1970s and 1980s, but waned thereafter, without resolution. Although DNA data have been produced, implications are not understood. We examined the polymorphims of Odh in several species of bivalves and gastropods, and the kinetic properties (apparent Km) of the different isozymes in the scallop Euvola ziczac that indicates an apparent case of overdominance of the heterozygous individuals. The question "which of the two hypothesis is correct" has shifted with time to "how much influence did each factor have in the maintenance of genetic variation".

Polymorphisms of octopine dehydrogenase (Odh) in mollusks and implications for the neutralism-selectionism hypothesis.

Octopine dehydrogenase (Odh) was examined in several species of bivalves and gastropods and complemented with bibliographic data, to assess the controversy between neutralism and selectionism in explaining the maintenance of genetic variation in natural populations. This debate was the center of the molecular evolution and population genetic research in the 1970s and 1980s, but waned thereafter, without resolution. Although DNA data have been produced, implications are not understood. We examined the polymorphims of Odh in several species of bivalves and gastropods, and the kinetic properties (apparent Km) of the different isozymes in the scallop Euvola ziczac that indicates an apparent case of overdominance of the heterozygous individuals. The question "which of the two hypothesis is correct" has shifted with time to "how much influence did each factor have in the maintenance of genetic variation".

[Chromosomes isolation from scallop oocytes]. / Obtención de cromosomas de vieiras a partir de ovocitos.

A methodology for chromosome isolation from non fertilized oocytes of Euvola ziczac and Nodipecten nodosus is presented. It solves most of the common problems found during preparation of samples such as the high yolk concentration, chromosome condensation and the loss of biological material during solution changes.

Obtencion de cromosomas de vieiras a partir de ovocitos / Chromosomes isolation from scallop oocytes

Se describe una metodología para la obtención de cromosomas a partir de ovocitos no fecundados de las vieiras Euvola ziczac y Nodipecten nodosus. Esta metodología resuelve los problemas debidos a la alta concentración de material de reserva en los ovocitos, la condensación excesiva de los cromosomas y la pérdida de material biológico durante su paso de una solución a outra. Es aplicable y adaptable a otros bivalvos.