Comparison of two surrogate estimates of insulin resistance to predict cardiovascular disease in apparently healthy individuals

Background and aims: Insulin resistance is associated with a cluster of abnormalities that increase cardiovascular disease (CVD). Several indices have been proposed to identify individuals who are insulin resistant, and thereby at increased CVD risk. The aim of this study was to compare the abilities of 3 indices to accomplish that goal: 1) plasma triglyceride × glucose index (TG × G); 2) plasma triglyceride/high-density lipoprotein cholesterol ratio (TG/HDL-C); and 3) Metabolic Syndrome (MetS). Methods and results: In a population sample of 723 individuals (486 women and 237 men, 50 ± 16 and 51 ± 16 years old, respectively), baseline demographic and metabolic variables known to increase CVD risk and incident CVD were compared among individuals defined as high vs. low risk by: TG × G; TG/HDL-C; or MetS. CVD risk profiles appeared comparable in high risk subjects, irrespective of criteria. Crude incidence of CVD events was increased in high risk subjects: 12.2 vs. 5.3% subjects/10 years, p = 0.005 defined by TG/HDL-C; 13.4 vs. 5.3% subjects/10 years, p = 0.002 defined by TG × G; and 13.4% vs. 4.5% of subjects/10 years, p < 0.001 in subjects with the MetS. The area under the ROC curves to predict CVD were similar, 0.66 vs. 0.67 for TG/HDL-C and TG × G, respectively. However, when adjusted by age, sex and multiple covariates, hazard ratios for incident CVD were significantly increased in high risk patients classified by either TG/HDL-C ratio (2.18, p = 0.021) or MetS (1.93, p = 0.037), but not by TG × G index (1.72, p = 0.087). Conclusion: Although the 3 indices identify CVD risk comparably, the TG × G index seems somewhat less effective at predicting CVD.Facultad de Ciencias Médica

ROL DE LOS CITOCROMOS P450 (CLAN CYP4) DEL INTEGUMENTO DE Triatoma infestans EN LA RESISTENCIA A DELTAMETRINA

Triatoma infestans es el principal vector de la enfermedad de Chagas en el Cono Sur de Sudamérica. Su control se basa en el rociado con insecticidas piretroides (principalmente deltametrina); sin embargo, desde hace varios años se vienen detectando fallas de control debido al desarrollo de poblaciones resistentes. Dentro de los mecanismos más relevantes en el fenómeno de resistencia se destacan: una mayor capacidad de metabolizar el insecticida debido a un aumento en la expresión de genes relacionados con detoxificación (resistencia metabólica), mutaciones que alteran el sitio de acción (resistencia kdr), y un engrosamiento cuticular que provoca una disminución en la penetración del insecticida (factor cuticular).&nbsp; En nuestro laboratorio se ha demostrado por primera vez en insecto que existen diferencias significativas en la cantidad de hidrocarburos cuticulares en especímenes T. infestans resistentes a piretroides, junto con un grosor aumentado de la cutícula. Estas características se correlacionan con una penetración reducida del insecticida. &nbsp;Aunque es bien sabido que los procesos de detoxificación de xenobióticos ocurren principalmente en el cuerpo graso de los insectos, los insecticidas de contacto encuentran en el integumento (el tejido más externo de los insectos) la primera barrera y es en este tejido donde se produce la primera interacción. Las citocromo P450 monoxigenasas (P450) constituyen una de las mayores superfamilias de enzimas encontradas en la naturaleza, catalizando la conversión de compuestos lipofílicos (tanto endógenos como xenobióticos) en derivados más hidrofílicos. Debido a su gran abundancia, los genes P450 (CYP) se asignan en familias y subfamilias; también se utiliza una agrupación de mayor orden denominada clan, encontrándose 4 clanes en la naturaleza. Varias subfamilias del clan 3 y clan 4 en insectos hay sufrido expansiones génicas, resultando en "blooms" de P450 linaje específicos, que han sido asociados con resistencia a insecticidas. Como parte de mi plan de tesis,&nbsp; y a partir de la información disponible del transcriptoma de integumento de T. infestans, hemos comenzado con el estudio de los genes CYP de integumento. Hemos detectamos que la detoxificación de deltametrina comienza en el integumento de vinchucas resistentes, con potencial participación de P450 del clan 4. Dentro de los 15 genes estudiados, dos de ellos -CYP3093A11 y CYP4EM10- se encuentran constitutivamente sobreexpresados en el integumento (pero no en otros tejidos) de vinchucas resistentes. Cuando estos dos genes fueron silenciados específicamente mediante ARN de interferencia, otro gen del clan CYP4 resultó sobreexpresado en el integumento, posiblemente como respuesta al silenciamiento de los genes antes mencionados. Estos resultados permitieron tener una primera aproximación para comenzar a estudiar el rol de los citocromos P450 del integumento de T. infestans en la detoxificación de deltametrina. Esta información contribuye a la hipótesis de que hay múltiples mecanismos participando en el complejo fenómeno de resistencia a insecticidas. En este sentido, se demuestra que el tejido epidérmico contribuye no solo con la resistencia cuticular, sino también con una activa participación en la resistencia metabólica

Identification and characterization of a novel non-structural protein of bluetongue virus

Bluetongue virus (BTV) is the causative agent of a major disease of livestock (bluetongue). For over two decades, it has been widely accepted that the 10 segments of the dsRNA genome of BTV encode for 7 structural and 3 non-structural proteins. The non-structural proteins (NS1, NS2, NS3/NS3a) play different key roles during the viral replication cycle. In this study we show that BTV expresses a fourth non-structural protein (that we designated NS4) encoded by an open reading frame in segment 9 overlapping the open reading frame encoding VP6. NS4 is 77–79 amino acid residues in length and highly conserved among several BTV serotypes/strains. NS4 was expressed early post-infection and localized in the nucleoli of BTV infected cells. By reverse genetics, we showed that NS4 is dispensable for BTV replication in vitro, both in mammalian and insect cells, and does not affect viral virulence in murine models of bluetongue infection. Interestingly, NS4 conferred a replication advantage to BTV-8, but not to BTV-1, in cells in an interferon (IFN)-induced antiviral state. However, the BTV-1 NS4 conferred a replication advantage both to a BTV-8 reassortant containing the entire segment 9 of BTV-1 and to a BTV-8 mutant with the NS4 identical to the homologous BTV-1 protein. Collectively, this study suggests that NS4 plays an important role in virus-host interaction and is one of the mechanisms played, at least by BTV-8, to counteract the antiviral response of the host. In addition, the distinct nucleolar localization of NS4, being expressed by a virus that replicates exclusively in the cytoplasm, offers new avenues to investigate the multiple roles played by the nucleolus in the biology of the cell

Report on the Human Genome Initiative

The report urges DOE and the Nation to commit to a large. multi-year. multidisciplinary. technological undertaking to order and sequence the human genome. This effort will first require significant innovation in general capability to manipulate DNA. major new analytical methods for ordering and sequencing. theoretical developments in computer science and mathematical biology, and great expansions in our ability to store and manipulate the information and to interface it with other large and diverse genetic databases. The actual ordering and sequencing involves the coordinated processing of some 3 billion bases from a reference human genome. Science is poised on the rudimentary edge of being able to read and understand human genes. A concerted. broadly based. scientific effort to provide new methods of sufficient power and scale should transform this activity from an inefficient one-gene-at-a-time. single laboratory effort into a coordinated. worldwide. comprehensive reading of &quot;the book of man&quot;. The effort will be extraordinary in scope and magnitude. but so will be the benefit to biological understanding. new technology and the diagnosis and treatment of human disease

Impaired RNA incorporation and dimerization in live attenuated leader-variants of SIV(mac239)

BACKGROUND: The 5' untranslated region (UTR) or leader sequence of simian immunodeficiency virus (SIV(mac239)) is multifunctional and harbors the regulatory elements for viral replication, persistence, gene translation, expression, and the packaging and dimerization of viral genomic RNA (vRNA). We have constructed a series of deletions in the SIV(mac239 )leader sequence in order to determine the involvement of this region in both the packaging and dimerization of viral genomic RNA. We also assessed the impact of these deletions upon viral infectiousness, replication kinetics and gene expression in cell lines and monkey peripheral blood mononuclear cells (PBMC). RESULTS: Regions on both sides of the major splice donor (SD) were found to be necessary for the efficiency and specificity of viral genome packaging. However, stem-loop1 is critical for both RNA encapsidation and dimerization. Downstream elements between the splice donor and the initiation site of SIV-Gag have additive effects on RNA packaging and contribute to a lesser degree to RNA dimerization. The targeted disruption of structures on both sides of the SD also severely impacts viral infectiousness, gene expression and replication in both CEMx174 cells and rhesus PBMC. CONCLUSION: In the leader region of SIV(mac239), stem-loop1 functions as the primary determinant for both RNA encapsidation and dimerization. Downstream elements between the splice donor and the translational initiation site of SIV-Gag are classified as secondary determinants and play a role in dimerization. Collectively, these data signify a linkage between the primary encapsidation determinant of SIV(mac239 )and RNA dimerization

Should the first blood pressure reading be discarded?

We evaluated the consequences of excluding the first of three blood pressure (BP) readings in different settings: a random population sample (POS, n=1525), a general practice office (GPO, n=942) and a specialized hypertension center (SHC, n=462). Differences between systolic and diastolic BP (SBP and DBP) estimates obtained including and excluding the first reading were compared and their correlation with ambulatory BP monitoring (ABPM) was estimated. The samples were divided into quartiles according to the difference between the third and the first SBP (3-1ΔSBP). SBP decreased through sequential readings, 3-1ΔSBP was -5.5 ± 9.7 mm Hg (P<0.001), -5.1 ± 10.4 mm Hg (P<0.001) and -6.1 ± 9.3 mm Hg (P<0.001) for POS, GPO and SHC, respectively. However, individuals included in the top quartile of 3-1ΔSBP showed their highest values on the third reading. The mean SBP estimate was significantly higher excluding the first reading (P<0.001), but the differences among both approaches were small (1.5-1.6 mm g). Moreover, the correlation between SBP values including and excluding the first reading and daytime ABPM were comparable (r = 0.69 and 0.68, respectively). Similar results were observed for DBP. In conclusion, our study does not support the notion of discarding the first BP measurement and suggests that it should be measured repeatedly, regardless the first value.Facultad de Ciencias Médica

Helix movement is coupled to displacement of the second extracellular loop in rhodopsin activation

The second extracellular loop (EL2) of rhodopsin forms a cap over the binding site of its photoreactive 11-cis retinylidene chromophore. A crucial question has been whether EL2 forms a reversible gate that opens upon activation or acts as a rigid barrier. Distance measurements using solid-state 13C NMR spectroscopy between the retinal chromophore and the β4 strand of EL2 show that the loop is displaced from the retinal binding site upon activation, and there is a rearrangement in the hydrogen-bonding networks connecting EL2 with the extracellular ends of transmembrane helices H4, H5 and H6. NMR measurements further reveal that structural changes in EL2 are coupled to the motion of helix H5 and breaking of the ionic lock that regulates activation. These results provide a comprehensive view of how retinal isomerization triggers helix motion and activation in this prototypical G protein-coupled receptor. © 2009 Nature America, Inc. All rights reserved

Quantitative evaluation of vimentin expression in tumour stroma of colorectal cancer

Recent studies have identified vimentin, a type III intermediate filament, among genes differentially expressed in tumours with more invasive features, suggesting an association between vimentin and tumour progression. The aim of this study, was to investigate whether vimentin expression in colon cancer tissue is of clinical relevance. We performed immunostaining in 142 colorectal cancer (CRC) samples and quantified the amount of vimentin expression using computer-assisted image analysis. Vimentin expression in the tumour stroma of CRC was associated with shorter survival. Overall survival in the high vimentin expression group was 71.2% compared with 90.4% in the low-expression group (P=0.002), whereas disease-free survival for the high-expression group was 62.7% compared with 86.7% for the low-expression group (P=0.001). Furthermore, the prognostic power of vimentin for disease recurrence was maintained in both stage II and III CRC. Multivariate analysis suggested that vimentin was a better prognostic indicator for disease recurrence (risk ratio=3.5) than the widely used lymph node status (risk ratio=2.2). Vimentin expression in the tumour stroma may reflect a higher malignant potential of the tumour and may be a useful predictive marker for disease recurrence in CRC patients