Predicción molecular de los triglicéridos de la grasa láctea de oveja por cromatografía líquida de alta eficacia en fase inversa

115 individual peaks were obtained by high-performance liquid chromatography of the sheep milk fat. Triglyceride components of the chromatographic peaks were predicted by means of mathematical equations relationing the log k' of the chromatographic peaks to the molecular variables, equivalent carbon number (ECN) of the possible triglycerides, and chain length (CL) and number of double bounds (DB) of each of the fatty acids of the triglyceride. The 12 main fatty acids obtained by gas chromatography of the total triglyceride fraction were used to estimate the triglyceride composition of the sheep milk fat. The triglycerides presenting high random percentages were considered the principal molecular species when more than one triglyceride were predicted in a chromatographic peak. The main estimated triglycerides of the sheep milk fat were C4:0-C16:0-C16:0, C6:0-C14:0-C16:0, C4:0-C14:0-C16:00, C4:0-C16:0-C18:1 and C6:0-C14:0-C18:1.El análisis por cromatografía líquida de alta eficacia de los triglicéridos de la leche de oveja obtuvo 115 picos individuales. Los triglicéridos componentes de los picos cromatográficos fueron estimados mediante ecuaciones matemáticas que relacionaban el log k' de los picos cromatográficos con las variables moleculares, número equivalente de carbonos (NEC) de los posibles triglicéridos, y longitud de cadena (LC) y número de dobles enlaces (DE) de cada uno de los ácidos grasos del triglicérido. Para la estimación de la composición triglicérica de la grasa láctea se consideraron solamente los 12 ácidos grasos mayoritarios obtenidos en el análisis por cromatografía de gases de la fracción triglicérica total. Los triglicéridos que presentaron altos porcentajes según el cálculo de la composición al azar fueron considerados los principales componentes moleculares cuando en un pico cromatográfico se predecía más de un triglicérido. Los triglicéridos estimados más abundantes en la grasa láctea de oveja fueron C4:0-C16:0-C16:0, C6:0-C14:0-C16:0, C4:0-C14:0-C16:00, C4:0-C16:0-C18:1 y C6:0-C14:0-C18:

DNA methylation epigenotypes in breast cancer molecular subtypes

12 páginas, 3 figuras, 3 tablas.-- et al.[Introduction]: Identification of gene expression-based breast cancer subtypes is considered a critical means of prognostication. Genetic mutations along with epigenetic alterations contribute to gene-expression changes occurring in breast cancer. So far, these epigenetic contributions to sporadic breast cancer subtypes have not been well characterized, and only a limited understanding exists of the epigenetic mechanisms affected in those particular breast cancer subtypes. The present study was undertaken to dissect the breast cancer methylome and to deliver specific epigenotypes associated with particular breast cancer subtypes. [Methods]: By using a microarray approach, we analyzed DNA methylation in regulatory regions of 806 cancer-related genes in 28 breast cancer paired samples. We subsequently performed substantial technical and biologic validation by pyrosequencing, investigating the top qualifying 19 CpG regions in independent cohorts encompassing 47 basal-like, 44 ERBB2+ overexpressing, 48 luminal A, and 48 luminal B paired breast cancer/adjacent tissues. With the all-subset selection method, we identified the most subtype-predictive methylation profiles in multivariable logistic regression analysis. [Results]: The approach efficiently recognized 15 individual CpG loci differentially methylated in breast cancer tumor subtypes. We further identified novel subtype-specific epigenotypes that clearly demonstrate the differences in the methylation profiles of basal-like and human epidermal growth factor 2 (HER2)-overexpressing tumors. [Conclusions]: Our results provide evidence that well-defined DNA methylation profiles enable breast cancer subtype prediction and support the utilization of this biomarker for prognostication and therapeutic stratification of patients with breast cancer.This work was supported by grants from project CGL2008-01131 (Departamento de Sanidad del Gobierno Vasco), S-PE08UN45 and PE09BF02 (Departamento de Ciencia y Tecnologia del Gobierno Vasco), BIO2008-04212, and RD06/0020/1019 (Red Tematica de Investigacion Cooperativa en Cancer, RTICC) from the MICINN. The CIBER de Enfermedades Raras is an initiative of the ISCIII. NGB had a doctoral fellowship from the Basque Government (Departamento de Educacion, Universidades e Investigacion).Peer reviewe

Comparison of dynamic headspace methods used for the analysis of the volatile composition of Spanish PDO ewe's raw milk cheeses

Different dynamic headspace (DHS) methods used for determination of volatile compounds in cheeses were compared. Three different laboratories using gas chromatography coupled to mass spectrometry carried out the analyses of volatile compounds of Spanish Protected Designation of Origin ewe's raw milk cheeses. One laboratory used "purge and trap" (P&T) with thermal desorption of the trap by ultrafast microwave heating (MWH) and the other two laboratories used P&T with thermal desorption of the trap by resistive heating (RH). Each method detected around 78-85 different individual compounds which belonged to different chemical groups, namely, acids, alcohols, ketones, esters, aldehydes, sulphur compounds, hydrocarbons and terpenes. Using the P&T-MHW method, larger percentages of acids and aldehydes in the cheeses were found compared with the P&T-RH methods, whereas the contrary occurred for the percentages of alcohols and ketones. Differences in the percentages of some volatile compounds such as ketones, alcohols and acids between the laboratories using P&T-RH under different analytical conditions were also recorded. The results pointed out differences in the selectivity for the extraction of various volatile compounds from cheese samples according to the DHS methods used, particularly when using tenax or graphitised carbon as trap absorbents. In spite of these differences, both P&T-MWH and P&T-RH methods were equally satisfactory for the comparison of the different cheese varieties. However, each of the DHS methods was more suitable for the characterisation of the volatile compounds of a particular cheese type. © INRA, EDP Sciences, 2005