Effect of human immunodeficiency virus infection on hepatitis C virus infection in hemophiliacs

Chronic liver disease due to hepatitis C virus (HCV) infection is a major problem in hemophiliacs. Recent reports suggested that hemophiliacs coinfected with hepatitis C virus and human immunodeficiency virus (HIV) have an increased incidence of liver failure but the mechanism of accelerated liver injury is not clear. We tested plasma from 100 hemophiliacs for anti-HCV by second generation ELISA, anti-HIV by EIA, and HCV RNA and HIV RNA by branched DNA and polymerase chain reaction assays to determine if hemophiliacs coinfected with HCV and HIV have higher HCV RNA levels and more active liver disease. Seventy-nine (79%) patients were anti-HCV positive, of whom 85% were HCV RNA positive. None of the anti-HCV-negative patients had detectable HCV RNA in plasma. Forty-two (42%) patients were anti-HIV positive, of whom 47% had detectable HIV RNA. All the anti-HIV-positive patients were also anti-HCV positive. The prevalence of both anti-HCV and anti-HIV increased significantly with age. There was no difference in HCV RNA levels between anti-HIV-positive and anti-HIV-negative patients (mean: 21±4 vs 18±5 Meq/ml), although HCV RNA levels were significantly higher in anti-HIV-positive patients with CD4 counts<200/mm 3 ( P =0.008). There was an inverse correlation between HCV RNA levels and CD4 counts but no correlation was found between HCV RNA and serum aminotransferase levels. We found a high prevalence of HCV and HIV coinfection in our hemophiliacs. Hepatitis C virus replication appears to be increased in patients with severe immunodeficiency secondary to progressive HIV infection. However, there was no correlation between HCV RNA and serum ALT level, suggesting that HCV is not directly cytopathic.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44427/1/10620_2005_Article_BF02088247.pd

The impact of agricultural management on soil aggregation and carbon storage is regulated by climatic thresholds across a 3000 km European gradient

Organic carbon and aggregate stability are key features of soil quality and are important to consider when evaluating the potential of agricultural soils as carbon sinks. However, we lack a comprehensive understanding of how soil organic carbon (SOC) and aggregate stability respond to agricultural management across wide environmental gradients. Here, we assessed the impact of climatic factors, soil properties and agricultural management (including land use, crop cover, crop diversity, organic fertilization, and management intensity) on SOC and the mean weight diameter of soil aggregates, commonly used as an indicator for soil aggregate stability, across a 3000 km European gradient. Soil aggregate stability (-56%) and SOC stocks (-35%) in the topsoil (20 cm) were lower in croplands compared with neighboring grassland sites (uncropped sites with perennial vegetation and little or no external inputs). Land use and aridity were strong drivers of soil aggregation explaining 33% and 20% of the variation, respectively. SOC stocks were best explained by calcium content (20% of explained variation) followed by aridity (15%) and mean annual temperature (10%). We also found a threshold-like pattern for SOC stocks and aggregate stability in response to aridity, with lower values at sites with higher aridity. The impact of crop management on aggregate stability and SOC stocks appeared to be regulated by these thresholds, with more pronounced positive effects of crop diversity and more severe negative effects of crop management intensity in nondryland compared with dryland regions. We link the higher sensitivity of SOC stocks and aggregate stability in nondryland regions to a higher climatic potential for aggregate-mediated SOC stabilization. The presented findings are relevant for improving predictions of management effects on soil structure and C storage and highlight the need for site-specific agri-environmental policies to improve soil quality and C sequestration

A reflection on HIV/AIDS research after 25 years

Dr. Robert C. Gallo provides a personal reflection on the 25 year history of AIDS

An integrative genomics approach identifies Hypoxia Inducible Factor-1 (HIF-1)-target genes that form the core response to hypoxia

The transcription factor Hypoxia-inducible factor 1 (HIF-1) plays a central role in the transcriptional response to oxygen flux. To gain insight into the molecular pathways regulated by HIF-1, it is essential to identify the downstream-target genes. We report here a strategy to identify HIF-1-target genes based on an integrative genomic approach combining computational strategies and experimental validation. To identify HIF-1-target genes microarrays data sets were used to rank genes based on their differential response to hypoxia. The proximal promoters of these genes were then analyzed for the presence of conserved HIF-1-binding sites. Genes were scored and ranked based on their response to hypoxia and their HIF-binding site score. Using this strategy we recovered 41% of the previously confirmed HIF-1-target genes that responded to hypoxia in the microarrays and provide a catalogue of predicted HIF-1 targets. We present experimental validation for ANKRD37 as a novel HIF-1-target gene. Together these analyses demonstrate the potential to recover novel HIF-1-target genes and the discovery of mammalian-regulatory elements operative in the context of microarray data sets

Hypoxia Inducible Factor 1-Alpha (HIF-1 Alpha) Is Induced during Reperfusion after Renal Ischemia and Is Critical for Proximal Tubule Cell Survival

Acute tubular necrosis (ATN) caused by ischemia/reperfusion (I/R) during renal transplantation delays allograft function. Identification of factors that mediate protection and/or epithelium recovery could help to improve graft outcome. We studied the expression, regulation and role of hypoxia inducible factor 1-alpha (HIF-1 α), using in vitro and in vivo experimental models of I/R as well as human post-transplant renal biopsies. We found that HIF-1 α is stabilized in proximal tubule cells during ischemia and unexpectedly in late reperfusion, when oxygen tension is normal. Both inductions lead to gene expression in vitro and in vivo. In vitro interference of HIF-1 α promoted cell death and in vivo interference exacerbated tissue damage and renal dysfunction. In pos-transplant human biopsies, HIF-1 α was expressed only in proximal tubules which exhibited normal renal structure with a significant negative correlation with ATN grade. In summary, using experimental models and human biopsies, we identified a novel HIF-1 α induction during reperfusion with a potential critical role in renal transplant

Correlation between serum HCV RNA and aminotransferase levels in patients with chronic HCV infection

Cross-sectional studies on the correlation between serum hepatitis C virus (HCV) RNA and alanine aminotransferase (ALT) levels in patients with chronic hepatitis C have yielded conflicting results. We conducted a longitudinal study to examine the correlation between HCV viremia and serum ALT levels in individual patients over time. Serial samples (mean 9) from 25 patients with chronic HCV infection, including interferon-treated and untreated immunocompetent and immunosuppressed patients, collected over a period of 1–4.8 years (mean 2.6 years) were tested for HCV RNA and ALT levels using a highly reproducible quantitative (bDNA) assay. A significant correlation was found between serum HCV RNA and ALT levels in the patients who received IFN therapy, but no correlation was observed in the untreated patients. Among the untreated patients, the immunosuppressed patients had significantly higher HCV RNA levels (39±4 vs 3.6±8 Meq/ml, P <0.0001) but significantly lower ALT (56±11 vs 97±12 units/liter, P =0.03) levels when compared to the immunocompetent ones. In summary, we found no correlation between serum HCV RNA and ALT levels in chronic hepatitis C patients who are not receiving interferon therapy. Immunosuppression results in higher HCV RNA but lower ALT levels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44425/1/10620_2005_Article_BF02071402.pd

Diseño e implementación de la estructura organizacional y manual de funciones para la toma de decisiones en la empresa soluciones y proyectos laborales S.A.S.

Diseñar e implementar la estructura organizacional en la empresa Proyectos & Soluciones Laborales S.A.S. Estructura que se ajusta a las características propias de la empresa, capaz de hacer frente a las condiciones actuales de los mercados y que permita darle base sólida a un proceso de dirección que ayude lograr un crecimiento en cultura organizacional y productividad.Introducción. -- 1. Planteamiento del problema. -- 1.1. Antecedentes. -- 2. Formulación del problema. -- 3. Objetivos. -- 3.1. Objetivo general. -- 3.2. Objetivos específicos. -- 4. Justificación. -- 5. Marcos referenciales. -- 5.1. Marco teórico. -- 5.2. Marco conceptual. -- 5.3. Marco contextual. -- 5.4. Marco legal. -- 6. Metodología. -- 6.1.Tipo de estudio. -- 6.2.Método de investigación:. -- 6.3.Fases de la investigación. -- 7. Desarrollo de objetivos. -- 7.1.Proponer procesos estructurales en la empresa Soluciones y proyectos laborales S.A.S. -- 7.1.1. Resultados de la encuesta. -- 7.2.Documentar los procesos que serán implementados y manejados por el personal de la empresa Soluciones y proyectos laborales S.A.S. -- 7.3. Socialización del proyecto en base a la implementación y formalización de los procesos y el manual de funciones en la empresa Soluciones y proyectos laborales S.A.S. -- 7.3.1.Resultados de la implementación. -- 7.4.Elaborar un análisis financiero de la empresa.-- 8. Conclusiones. -- 8.1.Conclusiones de acuerdo al número de objetivos Específicos. -- 9. Recomendaciones. -- Lista de referencias. -- Apéndice. -- Vita