Posgrado e Investigación

The main objective of this research was analyzing variations about physical-chemical properties of Jatropha Curcas L. (JCL) oil by image processing. Ten samples with previous identification of the physical-chemical properties concerning such as the acid value, oxidation stability, water content, density and viscosity, was prepared. These parameters affect the oil quality and have significant importance in biofuels production. After oils characterization, all photographs was acquired in order to apply processing techniques to analyze the red, green and blue behavior corresponding to the oil property. Both red and green show useful behavior patterns, on the other hand blue is not recommended because of its instability

The effect of ABCA1 genetic variation on HDL-C levels has been widely documented, although studies in children are scarce. We recently found a frequent non-synonymous ABCA1 variant (R230C) exclusive to populations with Native American ancestry, associated with low HDL-C levels and other metabolic traits in adults. We genotyped R230C variant in 1253 healthy unrelated Mexican school-aged children aged 6-15 years (595 boys and 658 girls) to seek associations with HDL-C levels and other metabolic traits. HDL subclass distribution was analyzed in a subgroup of 81 age, gender and BMI-matched children. Individuals carrying the C230 allele showed a significantly lower HDL-C levels (P=2.9x10(-8)), and higher TC/HDL-C ratio, BMI, BMI z-score and percent fat mass (P=0.001, 0.049, 0.032 and 0.039, respectively). HDL size was smaller in R230C heterozygotes as compared to R230R homozygotes (P<0.05). Moreover, the proportion of HDL(2b) was lower, while the proportion of HDL(3a) and HDL(3b) particles was higher in R230C heterozygous and/or C230C homozygous individuals as compared to R230R homozygotes (P<0.05). Our data suggest that the R230C ABCA1 gene variant plays an important role in HDL-C level regulation and HDL subclass distribution in healthy Mexican school-aged children.

Previous studies in the Mexican population have failed to show an effect of apolipoprotein E (APOE) polymorphism on the lipid profile. The purpose of the present study was to determine the frequencies of APOE phenotypes, and their influence on lipid and apolipoprotein levels in a random sample of Mexican adolescents living in Mexico City. APOE polymorphism, fasting insulin levels, lipid levels, and apolipoprotein levels were determined in 420 adolescents. We found a high frequency of APOE*3 subjects (89.5%) and a low frequency of APOE*2 (3.0%) and APOE*4 (7.5%) subjects. The APOE*4 subjects (including APOE 4,3 and APOE 4,4) showed the highest concentrations of total cholesterol, low-density lipoprotein cholesterol, and apoB and the lowest high-density lipoprotein cholesterol levels, whereas carriers of the APOE*2 allele (APOE 3,2 and APOE 2,2) had the lowest values for total and low-density lipoprotein cholesterol and the highest concentrations of high-density lipoprotein cholesterol. No significant differences in triglyceride and insulin levels among subjects with different APOE polymorphisms were observed. Unlike previous studies in the Mexican population, our results show that lipid and lipoprotein levels are under the influence of APOE polymorphism. As in whites, APOE*4 may be a cardiovascular risk factor in the Mexican population.

The aim of the present study was to evaluate the role of the C-514T (rs1800588) gene polymorphism of the hepatic lipase (LIPC) as susceptibility marker for fatty liver in the Mexican population. The polymorphism was genotyped by 5' exonuclease TaqMan assays in a group of 1468 subjects (980 with and 488 without fatty liver) belonging to the Genetics of Atherosclerotic Disease (GEA) Mexican Study. Anthropometric and biochemical measurements were performed on all individuals. The polymorphism was not associated with fatty liver, however, under dominant model, the TT genotype was associated with increased levels of triglycerides (P=0.0002), apolipoprotein A1 (P=0.015), triglycerides/HDL-cholesterol index (P=0.046) and increased frequency of type 2 diabetes mellitus (P=0.045). On the other hand, the same genotype was associated with the presence of small LDLs (P=0.003). The risk analysis showed that under a dominant model, the LIPC C-514T polymorphism was associated with increased risk of type 2 diabetes (OR=1.42, P=0.029), hypertriglyceridemia (OR=1.36, P=0.006), and coronary artery calcification (CAC)≥1 (OR=1.44, P=0.015) and decreased risk of hypoalphalipoproteinemia (OR=0.78, P=0.036). The results suggest that the LIPC C-154T polymorphism is associated with cardiometabolic parameters and cardiovascular risk factors but not with fatty liver in Mexican population. The association detected with CAC indicates that this polymorphism could be a marker for subclinical atherosclerosis.

Apolipoprotein a, is a high molecular weight glycoproteic component of Lp(a), a molecule associated with coronary arterial disease. Apo(a) exhibits considerable size heterogeneity due to variable repetitions of the carbohydrate-containing structural unit, termed kringle. There are five different kringle forms and 10 different kringle 4 types. Apo(a) polymorphism and molecular weight depend on the number of copies of kringle 4 type 2. In this paper we describe a modified 3.75% and 6% discontinuous polyacrylamide gel system and Western-blot technique that shortness the assay time and improves the identification of apo(a) isoforms with a theoretical error of less than 1 kringle. The assay uses a standard curve prepared with five different recombinant apo(a) molecules, detected up to 50 ng of protein in Lp(a), showed a maximal resolution of 2 kringles and, with the use of third degree polynominal regression analysis, had an error of 0.01275. The inter-assay coefficient of variation was 1.7, 2, and 1.4 for the 14 K, 18 K, and 22 K phenotypes, whereas the intra-assay coefficient of variation was 0.32%, 0.18%, and 0.17%, respectively. It is possible that this modified method will diminish the number of putative null alleles so far detected in various studies, but most of all, we are certain that it can be of use in epidemiological studies due to its ease of use, speed, low cost, and enhanced number of samples that can be tested.

Little is known about qualitative abnormalities of high-density lipoproteins (HDL) in systemic lupus erythematosus (SLE). We studied distribution and composition of HDL subclasses in 30 premenopausal women with uncomplicated SLE, and 18 controls matched for age and sex. Plasma and HDL lipids were determined by colorimetric enzymatic assays, HDL size distribution by native gradient polyacrylamide gel electrophoresis (PAGE) and apolipoproteins in HDL by sodium dodecyl sulphate denaturing PAGE. Compared with controls, SLE patients had significantly lower proportions of HDL(2b) (-14.7%) and higher proportions of HDL(3b) (+8.8%) and HDL(3c) (+23.3%). Cholesteryl ester (-18%) and apolipoprotein AI (-9%) were lower, whereas triglycerides (+32%) and apolipoprotein E (+27%) were higher in SLE HDL (P < 0.05; for all). In the whole population, stepwise regression analysis showed that only insulin concentrations (R(2) = 0.327) and plasma total apo AI (R(2) = 0.114) accounted independently to the variance in HDL size. This study shows that HDL distribution and composition are abnormal in non-complicated SLE patients. These HDL abnormalities have been reported to be associated to impaired atheroprotective properties of HDL and prevalence of coronary heart disease. Therefore, they may contribute to the premature atherosclerosis observed in young women with SLE.