[Effects of occupational exposure to pesticides on semen quality of workers in an agricultural community of Merida state, Venezuela]. / Efectos de la exposición ocupacional a plaguicidas sobre la calidad del semen en trabajadores de una comunidad agrícola del estado Merida, Venezuela.

Numerous studies report adverse effects of pesticides on male reproductive health. The objectives of this study were to investigate whether there is a relationship between occupational exposure to pesticides and semen quality, and to determine whether chronic exposure to pesticides differentially affects semen quality in men of different ages. A comparative study of 64 farmers and 64 control men was performed. The farmers were interviewed to determine their occupational history and particularly, activities that may involve exposure to pesticides. Semen parameters were evaluated and a comparative analysis of semen variables between exposed and control groups, as well as between age groups: 18-29, 30-37 and 38-60 years was done. Significant alterations of some semen parameters in the exposed group were found, such as: decreases in sperm concentration, slow progressive motility and sperm membrane integrity; at the same time, increases in eosin Y positive and sperm DNA fragmentation index. The results obtained by age groups showed significant differences between exposed and control groups for the parameters of membrane integrity, eosin Y positive and sperm DNA fragmentation index, being the exposed group between 18-29 years that showed the highest altered cases of these parameters. Our results prove that occupational pesticide exposure is associated with alterations in sperm quality, creating a risk to farm workers in their reproductive capacity.

HIV-1 Nef associates with p22-phox, a component of the NADPH oxidase protein complex.

Altered neutrophil function may contribute to the development of AIDS during the course of HIV infection. It has been described that Nef, a regulatory protein from HIV, can modulate superoxide production in other cells, therefore altered superoxide production in neutrophils from HIV infected patients, could be secondary to a direct effect of Nef on components of the NADPH oxidase complex. In this work, we describe that Nef, was capable of increasing superoxide production in human neutrophils. Furthermore, a specific association between Nef and p22-phox, a membrane component of the NADPH oxidase complex, was found. We propose that this association may reflect a capability of Nef to modulate by direct association, the enzymatic complex responsible for one of the most efficient innate defense mechanisms in phagocytes, contributing to the pathogenesis of the disease.

[Evaluation of the quality of the human spermatozoon: comparison between spermatic DNA integrity and semen variables]. / Evaluación de la calidad del espermatozoide humano: comparación entre la integridad del ADN espermático y variables del semen.

Semen analysis does not have an absolute predictive value on fertility, however it is a reflection of male fertility potential, which is related to its spermatozoa quality and other semen variables. Great variability in human semen parameters has been demonstrated within a single individual, an observation that could explain why a male with low semen quality can successfully fertilize an egg. Although conventional semen analysis, such as sperm concentration, motility and morphology, provide important information about the clinical status of male fertility, new procedures to predict the sperm functional capability have been developed in the last decade, such as analysis of nuclear DNA integrity, which have improved considerably the clinical diagnosis of male infertility, and increased the knowledge about spermatozoa function. DNA fragmentation consist in interruptions, both in single and double DNA strains, that frequently occur in sperm samples from infertile patients. We have conducted a clinical study in semen samples from patients who have attended the Andrology laboratory of the University of Los Andes, between March 2007 and March 2009. The aim of this study was to compare sperm DNA integrity, analyzed by flow cytometry, with traditional semen parameters. Our results show remarkable correlations between conventional human semen variables and sperm chromatin integrity, contributing to asses an integral evaluation of sperm quality allowing the analysis of its fertilizing potential in clinical studies.

Altered T cell costimulation during chronic hepatitis B infection.

T-cell response to hepatitis B virus (HBV) is vigorous, polyclonal and multi-specific in patients with acute hepatitis who ultimately clear the virus, whereas it is narrow and inefficient in patients with chronic disease, where inappropriate early activation events could account for viral persistence. We investigated the induction of activation receptors and cytokine production in response to HBcAg and crosslinking of CD28 molecules, in CD4+ cells from a group of chronically infected patients (CIP) and naturally immune subjects (NIS). We demonstrated that CD4+ cells from CIP did not increase levels of CD40L and CD69 following stimulation with HBcAg alone or associated to CD28 crosslinking, in contrast to subjects that resolved the infection (p<0.01). Furthermore, CD4+ cells from CIP produced elevated levels of IL-10 in response to HBcAg. These results suggest that a predominant inhibitory environment may be responsible for altered T cell costimulation, representing a pathogenic mechanism for viral persistence.

[Cytotoxic effect of palladium (II) inclusion compounds in beta-cyclodextrin].

INTRODUCTION: Thiosemicarbazones and palladium (II) complexes have antineoplastic activities with mild side effects, for which they are considered new alternative antineoplastic drugs. However, the IC50 ranges of these complexes vary due to differences in their structure and solubility and their sensitivities for various cellular targets. Beta-cyclodextrin is an additive used to improve the solubility and stability of various drugs for therapeutic use, but the combination of beta-cyclodextrin with palladium (II) complexes and thiosemicarbazones has not been tested yet. OBJECTIVE: To study the cytotoxic effect of palladium (II) inclusion complexes in beta-cyclodextrin. MATERIALS AND METHODS: We tested the cytotoxic activity of palladium complexes combined with beta-cyclodextrin in the breast cancer cell line MCF-7 using a sulforhodamine B assay. RESULTS: We tested the antiproliferative activity of palladium (II) complexes with and without the ligands MePhPzTSC and Ph2PzTSC and with and without beta-cyclodextrin in MCF-7 cells and compared them to that of cisplatin. All combinations showed antiproliferative activity; however, the activity was greater for the combinations that included beta-cyclodextrin: ([Pd (MePhPzTSC) 2] • ß-CD and [Pd (Ph2PzTSC) 2] • ß-CD), at concentrations of 0.14 and 0.49 µM, respectively. The IC50 for this complex was 5-fold lower than that of the ligand-free combinations (1.4 and 2.9 µM, respectively). The IC50 for free palladium (II) complex was 0.571.24 µM and that for cisplatin was 6.87 µM. CONCLUSIONS: Beta-cyclodextrin significantly enhanced the cytotoxic activities of palladium (II) complexes and thiosemicarbazones probably by improving their solubility and bioavailability. The addition of beta-cyclodextrin is a possible strategy for designing new anticancer drugs.

[Role of human immunodeficiency virus in leukocytes apoptosis from infected patients]. / Papel del virus de la inmunodeficiencia humana en 1a apoptosis de leucocitos de pacientes infectados.

The hallmark of the immunodeficiency virus infection is a progressive detriment of the immune response which has been associated to a gradual loss of its responsible components, in particularly, CD4 positive T cells. Although this cell population is considered the main target of the virus, there is a recent deal of interest in studying other components that may not be targets of the virus, but are important elements to control infectious microorganisms and that have been demonstrated to be altered during HIV infection. Neutrophils (PMN) are innate immune components that play a fundamental role against HIV infection and these cells have been described as functionally altered during AIDS. It has been suggested that such a dysfunction could be attributed to an increased susceptibility of these cells to accelerated spontaneous apoptosis. However, the underlying mechanisms that induce programmed cell death of neutrophils remain unknown. In previous works we have explored some events involved during cell death of neutrophils from HIV infected patients. It is the purpose of this work to review the current knowledge of apoptosis signals in neutrophils and to discuss our own data about some mechanisms involved in spontaneous and Fas mediated apoptosis, which may contribute to understand neutrophils dysfunction during HIV infection.

Occupational exposure to organophosphate and carbamate pesticides affects sperm chromatin integrity and reproductive hormone levels among Venezuelan farm workers.

OBJECTIVES: Several reports suggest that chronic pesticide exposure may affect semen quality and male fertility in humans. The objective of this study was to evaluate the association between occupational exposure to organophosphate (OP) and carbamate (CB) pesticides and semen quality, as well as levels of reproductive and thyroid hormones of Venezuelan farm workers. METHODS: Thirty-five healthy men (unexposed group) and 64 male agricultural workers (exposed group) were recruited for clinical evaluation of fertility status. Fresh semen samples were evaluated for sperm quality and analyzed for DNA fragmentation index (DFI) by flow cytometry. Pesticide exposure was assessed by measuring erythrocyte acetylcholinesterase (AChE) and plasma butyrylcholinesterase (BuChE) with a Test-mate ChE field kit. Serum levels of total testosterone (Tt), follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), thyroid stimulating hormone (TSH) and free thyroxine (FT4) were analyzed using enzyme immunoassay kits. RESULTS: Evidence of pesticide exposure was found in 87.5% of farmers based on AChE and BuChE inhibition. Significant increments were observed in sperm DFI with significant decreases in some semen parameters. DFI was negatively correlated with BuChE, sperm concentration, morphology and vitality in these workers. The levels of Tt, PRL, FT4 and TSH appeared to be normal; however, there was a tendency for increased LH and FSH levels in exposed workers. CONCLUSIONS: Our results confirm the potential impact of chronic occupational exposure to OP/CB pesticides on male reproductive function, which may cause damage to sperm chromatin, decrease semen quality and produce alterations in reproductive hormones, leading to adverse reproductive health outcomes.

Diseño de una prueba diagnóstica casera para la detección de anticuerpos tipo IgG contra el virus de la hepatitis C: incorporación de la proteína de envoltura E2 y no estructural 2 (NS2) / Design of an in-house diagnostic test for IgG antibodies against hepatitis C virus detection: Incorporation of envelope protein E2 and non-structural protein 2 ( NS2)

Durante la infección por el virus de la hepatitis C (VHC), los anticuerpos específicos aparecen varias semanas posterior a la exposición, van dirigidos contra las diversas proteínas del virus incluyendo anticuerpos contra la envoltura viral (E2)y la proteína no estructural 2 (NS2). En este trabajo se diseñó un ensayo casero de ELISA que incorpora, además de NS3, NS5a, NS5b y el core, a las proteínas E2 y NS2 del VHC en sustitución de NS4, con el fin de evaluar su capacidad diagnóstica en comparación con un estuche comercial de 4ta generación. La validación de la prueba casera demostró una especificidad y sensibilidad similar a las obtenidas con el estuche comercial de 4ta generación (Biokit©), con un índice kappa igual a 0,969, al compararse con el mismo. Esto sugiere que la prueba diseñada podría utilizarse de manera segura para la detección de anticuerpos VHC específicos de tipo IgG para el diagnóstico de la hepatitis C y constituirse como una alternativa de producción nacional más económica.

During hepatitis C (HCV) infection specific antibodies appear several weeks after exposure, including viral envelope (E2) and non-structural protein 2 ( NS2). In this work we designed an in-house ELISA assay, that incorporate beside NS3, NS5a, NS5b and core, the HCVE2 and NS2 proteins in substitution of NS4, in order to evaluate its diagnostic utility as compared to a fourth generation commercial kit. The in-house test demonstrated a specificity and sensitivity similar to those obtained with the commercial kit, with a kappa index equal to 0.969, when it was compared with the 4th generation commercial kit (BioelisaBiokit ©), suggesting that our test could be used for the diagnosis of specific IgG antibodies detection against hepatitis C and to become a more economic national alternative.

Efecto citotóxico de los compuestos de inclusión de paladio (II) en la beta-ciclodextrina / Cytotoxic effect of palladium (II) inclusion compounds in beta-cyclodextrin

Resumen Introducción. Las tiosemicarbazonas y sus complejos de paladio (II) poseen actividad antineoplásica con pocos efectos secundarios, por lo cual se las considera como una nueva alternativa terapéutica. Sin embargo, existen diferencias en los rangos de la concentración inhibitoria media (CI50) asociada a la divergencia estructural y la solubilidad de los complejos, así como a la sensibilidad de los blancos celulares. La inclusión de fármacos en la beta-ciclodextrina con fines terapéuticos ha mejorado su solubilidad y estabilidad, pero los efectos de su combinación con los complejos de paladio (II) y las tiosemicarbazonas no se han comprobado aún. Objetivo. Estudiar el efecto citotóxico de los complejos de paladio en la beta-ciclodextrina. Materiales y métodos. La actividad citotóxica de los complejos de paladio en la beta-ciclodextrina se evaluó en la línea celular de cáncer de mama (MCF-7), empleando el método de la sulforodamina B. Resultados. Los ligandos MePhPzTSC y Ph2PzTSC, sus complejos de paladio (II) libres e incluidos en la beta-ciclodextrina y el cisplatino mostraron actividad citotóxica en la línea celular MCF-7; sin embargo, la citotoxicidad fue mayor con la inclusión en la beta-ciclodextrina ([Pd(MePhPzTSC)2]•ß-CD y [Pd(Ph2PzTSC)2]•ß-CD). La concentración inhibitoria media (CI50) para estos complejos se obtuvo en concentraciones de 0,14 y 0,49 μM, y con dosis hasta cinco veces inferiores comparadas con las concentraciones de los ligandos libres (1,4 y 2,9 μM), de los complejos de paladio (II) libres (0,57 y 1,24 μM) y del cisplatino (6,87 μM). Conclusiones. El uso de la beta-ciclodextrina mejoró significativamente la actividad citotóxica de las tiosemicarbazonas y sus complejos de paladio (II), lo cual probablemente está asociado al incremento de la solubilidad y biodisponibilidad del compuesto, estrategia que se puede sugerir para el diseño de futuros fármacos antineoplásicos.

Abstract Introduction: Thiosemicarbazones and palladium (II) complexes have antineoplastic activities with mild side effects, for which they are considered new alternative antineoplastic drugs. However, the IC50 ranges of these complexes vary due to differences in their structure and solubility and their sensitivities for various cellular targets. Beta-cyclodextrin is an additive used to improve the solubility and stability of various drugs for therapeutic use, but the combination of beta-cyclodextrin with palladium (II) complexes and thiosemicarbazones has not been tested yet. Objective: To study the cytotoxic effect of palladium (II) inclusion complexes in beta-cyclodextrin. Materials and methods: We tested the cytotoxic activity of palladium complexes combined with betacyclodextrin in the breast cancer cell line MCF-7 using a sulforhodamine B assay. Results: We tested the antiproliferative activity of palladium (II) complexes with and without the ligands MePhPzTSC and Ph2PzTSC and with and without beta-cyclodextrin in MCF-7 cells and compared them to that of cisplatin. All combinations showed antiproliferative activity; however, the activity was greater for the combinations that included beta-cyclodextrin: ([Pd (MePhPzTSC) 2] • ß-CD and [Pd (Ph2PzTSC) 2] • ß-CD), at concentrations of 0.14 and 0.49 μM, respectively. The IC50 for this complex was 5-fold lower than that of the ligand-free combinations (1.4 and 2.9 μM, respectively). The IC50 for free palladium (II) complex was 0.571.24 μM and that for cisplatin was 6.87 μM. Conclusions: Beta-cyclodextrin significantly enhanced the cytotoxic activities of palladium (II) complexes and thiosemicarbazones probably by improving their solubility and bioavailability. The addition of betacyclodextrin is a possible strategy for designing new anticancer drugs.

Efectos de la exposición ocupacional a plaguicidas sobre la calidad del semen en trabajadores de una comunidad agrícola del estado Mérida, Venezuela. / Effects of occupational exposure to pesticides on semen quality of workers in an agricultural community of Merida state, Venezuela.

Numerosos estudios informan de los efectos adversos de plaguicidas sobre la salud reproductiva masculina. Los objetivos de este estudio fueron investigar si existe una relación entre exposición ocupacional a plaguicidas y la calidad del semen, y determinar si la exposición crónica a plaguicidas afecta diferencialmente la calidad del semen de trabajadores de diferentes edades. Se realizó un estudio comparativo entre 64 agricultores y 64 hombres control. Los trabajadores agrícolas fueron entrevistados para determinar su historia ocupacional, particularmente las actividades que pueden involucrar exposición a plaguicidas. Se evaluaron los parámetros seminales y se hizo un análisis comparativo entre el grupo expuesto y control, así como entre los grupos de edad 18-29, 30-37 y 38-60 años. Se encontraron alteraciones significativas de algunos parámetros del semen en el grupo expuesto, tales como: disminuciones en la concentración, motilidad lenta progresiva e integridad de membrana espermática; a su vez, incrementos en eosina Y positiva e índice de fragmentación del DNA espermático. Los resultados obtenidos por grupo de edad mostraron diferencias significativas entre los grupos expuesto y control, para los parámetros de integridad de membrana, eosina Y positiva e índice de fragmentación del DNA espermático, siendo el grupo expuesto entre 18-29 años el que mostró mayores casos alterados de estos parámetros. Los resultados de este estudio comprueban que la exposición ocupacional a plaguicidas está asociada con alteraciones en la calidad espermática, creando riesgo para la capacidad reproductiva de los trabajadores del campo.

Numerous studies report adverse effects of pesticides on male reproductive health. The objectives of this study were to investigate whether there is a relationship between occupational exposure to pesticides and semen quality, and to determine whether chronic exposure to pesticides differentially affects semen quality in men of different ages. A comparative study of 64 farmers and 64 control men was performed. The farmers were interviewed to determine their occupational history and particularly, activities that may involve exposure to pesticides. Semen parameters were evaluated and a comparative analysis of semen variables between exposed and control groups, as well as between age groups: 18-29, 30-37 and 38-60 years was done. Significant alterations of some semen parameters in the exposed group were found, such as: decreases in sperm concentration, slow progressive motility and sperm membrane integrity; at the same time, increases in eosin Y positive and sperm DNA fragmentation index. The results obtained by age groups showed significant differences between exposed and control groups for the parameters of membrane integrity, eosin Y positive and sperm DNA fragmentation index, being the exposed group between 18-29 years that showed the highest altered cases of these parameters. Our results prove that occupational pesticide exposure is associated with alterations in sperm quality, creating a risk to farm workers in their reproductive capacity.

Antigen-induced regulatory T cells in HBV chronically infected patients.

T cell response against HBV is vigorous in patients with acute hepatitis who clear the virus, whereas it is weak and narrowly focused in patients with chronic disease. We report that following incubation with HBcAg, a population of CD4+FoxP3+ cells expressing phenotypic markers of both natural and induced Tregs, can be antigen-induced from peripheral mononuclear cells. Conversely, naive and naturally immune subjects did not increase CD4+FoxP3+ Tregs following stimulation with HBcAg, supporting the idea that natural Tregs are able to respond specifically to HBV antigen. Furthermore, increased frequencies of antigen-induced CD4+FoxP3+IL-10+ Tregs correlated with viral load, suggesting that antigen-induced Tregs could contribute to an inadequate response against the virus, leading to chronic infection and support the view that specific natural Tregs may be implicated in host immune tolerance during HBV infection.

Efectos de exposición ocupacional a plaguicidas sobre la integridad de la cromatina espermática

Objetivo: Evaluar los efectos de la exposición a plaguicidas organofosforados y carbamatos sobre la integridad de cromatina espermática en trabajadores agrícolas. Métodos: Se evaluaron 64 trabajadores del campo, con edades entre 18 y 55 años, de la comunidad rural de Bailadores, Municipio Rivas Dávila, Estado Mérida, Venezuela, expuestos directamente a plaguicidas. Para el diagnóstico de exposición a plaguicidas, fueron determinados los niveles de las colinesterasas eritrocitaria (AChE) y plasmática (PChE). Para evaluar la fertilidad masculina, a cada trabajador se le realizó seminograma y se les evaluó la integridad de la estructura de cromatina espermática mediante la técnica "Sperm Chromatin Structure Assay" (SCSA). Resultados: El 25% de los trabajadores agrícolas presentó niveles deprimidos de AChE y el 83% con niveles anormales de PChE, con una reducción <75% del nivel normal. El grupo con edades entre 18 y 28 años fue el más afectado. Diferencias significativas fueron obtenidas en los promedios de los niveles de colinesterasas entre los casos normales y alterados, tanto para AChE (3,95±0,42 vs. 2,72±0,16, ρ<0,0001) así como para PChE (2,08±0,25 vs. 1,43±0,32, ρ<0,0001). El 69,7% de los trabajadores con niveles anormales de PChE presentó alteración en el ADN espermático. Se encontró una correlación negativa significativa entre el Índice de Fragmentación de ADN (IDF) espermático y los niveles de PChE (ρ=0,02). Conclusiones: En trabajadores agrícolas expuestos directamente a plaguicidas organofosforados y carbamatos, un alto porcentaje presentó niveles anormalmente deprimidos de PChE, junto con alteración en el ADN espermático. Estos resultados demuestran que los trabajadores se encuentran con alto riesgo de exposición a los efectos tóxicos de plaguicidas, lo cual efectivamente se comprueba con los resultados de análisis de las enzimas colinesterasas y la aplicación de la técnica SCSA para determinar la integridad de la cromatina espermática.

Objective: To evaluate the effects of exposure to organophosphate and carbamate pesticides on the integrity of sperm chromatin in farm workers. Methods: In this study, we evaluated 64 farm workers, aged between 18 and 55 years, from the rural community of Bailadores, Municipality of Rivas Dávila, Mérida State, Venezuela, directly exposed to pesticides. For the diagnosis of pesticide exposure, levels of erythrocyte (AChE) and plasma (PchE) cholinesterases. were determined. To evaluate male fertility, each worker underwent semen analysis and the integrity of sperm chromatin structure was assessed using the "Sperm Chromatin Structure Assay (SCSA) technique. Results: The results of this study showed that 25% of agricultural workers had depressed levels of AChE and a majority, 83%, was found with abnormal levels of PChE. The group with corresponding ages between 18 and 28 years was the most affected. Significant differences were obtained in the average cholinesterase levels between normal and altered cases for both AChE (3.95 ± 0.42 vs. 2.72 ± 0.16, p < 0.0001) and PChE (2.08 ± 0.25 vs. 1.43 ± 0.32, ρ < 0.0001). Among workers with abnormal PChE levels, 69.7% presented alterations of sperm chromatin structure. There was a significant negative correlation between sperm DNA Fragmentation Index (DFI) and the levels of PChE (ρ = 0.02). Conclusions: In agricultural workers directly exposed to organophosphate and carbamate pesticides, a high percentage showed abnormally depressed PChE, along with altered sperm chromatin structure. These results show that farm workers are at high risk of exposure to the toxic effects of pesticides, which were effectively demonstrated with the results of analysis of cholinesterase enzymes and the implementation of the SCSA technique for determining the status of the sperm chromatin structure.

Evaluación de la calidad del espermatozoide humano: comparación entre la integridad del ADN espermático y variables del semen / Evaluation of the quality of the human spermatozoon: comparison between spermatic DNA integrity and semen variables

El análisis del semen no tiene valor predictivo absoluto de fertilidad, pero informa sobre el potencial de fertilidad del varón, el cual está relacionado con la calidad de sus espermatozoides y de otras variables del semen. Se ha comprobado que los valores del semen pueden mostrar gran variabilidad en un mismo individuo. Esto explica por que un hombre cuyas variables no son absolutamente normales, puede lograr un embarazo en su pareja. Dentro de los parámetros tradicionalmente utilizados en la evaluación clínica de la fertilidad masculina se encuentran: la concentración, la movilidad y la morfología espermática; además de medir estas variables, nuevos procedimientos han sido incorporados para evaluar la capacidad funcional de los espermatozoides, uno de los que ha alcanzado particular importancia en la última década es la medida de la integridad del ADN nuclear. La fragmentación del ADN consiste en interrupciones en las cadenas simples o dobles del ADN que ocurre frecuentemente en la muestra de pacientes no fértiles. Se ha llevado a cabo un estudio clínico, en muestras de semen provenientes de pacientes que acudieron al laboratorio de Andrología de la Universidad de los Andes, colectadas entre marzo del 2007 y marzo del 2009, a fin de establecer comparaciones entre los parámetros convencionales y la medición de la integridad de la cromatina espermática, mediante citometría de flujo. Los resultados obtenidos mostraron correlaciones evidentes entre los parámetros convencionales y la integridad del ADN espermático y aportan datos de gran utilidad en el estudio clínico integral de la infertilidad masculina.

Semen analysis does not have an absolute predictive value on fertility, however it is a reflection of male fertility potential, which is related to its spermatozoa quality and other semen variables. Great variability in human semen parameters has been demonstrated within a single individual, an observation that could explain why a male with low semen quality can successfully fertilize an egg. Although conventional semen analysis, such as sperm concentration, motility and morphology, provide important information about the clinical status of male fertility, new procedures to predict the sperm functional capability have been developed in the last decade, such as analysis of nuclear DNA integrity, which have improved considerably the clinical diagnosis of male infertility, and increased the knowledge about spermatozoa function. DNA fragmentation consist in interruptions, both in single and double DNA strains, that frequently occur in sperm samples from infertile patients. We have conducted a clinical study in semen samples from patients who have attended the Andrology laboratory of the University of Los Andes, between March 2007 and March 2009. The aim of this study was to compare sperm DNA integrity, analyzed by flow cytometry, with traditional semen parameters. Our results show remarkable correlations between conventional human semen variables and sperm chromatin integrity, contributing to asses an integral evaluation of sperm quality allowing the analysis of its fertilizing potential in clinical studies.

Papel del virus de la inmunodeficiencia humana en la apoptosis de leucocitos de pacientes infectados / Role of human immunodeficiency virus in leukocytes apoptosis from infected patients

La infección por el virus de la inmunodeficiencia humana (VIH) se caracteriza por el deterioro progresivo de la respuesta inmune, asociado a una pérdida gradual de los elementos que la generan, especialmente de los linfocitos T CD4+. Aunque estas células son el principal blanco del virus, en la actualidad existe gran interés por el estudio de otros elementos celulares, que se encuentran alterados y que contribuyen al deterioro del paciente. Dentro de este grupo de células se encuentran los polimorfonucleares (PMN), células fundamentales en la defensa innata contra el VIH y cuya función está alterada en el curso de la enfermedad. Probablemente la causa de este deterioro se debe, en parte, a un incremento en su susceptibilidad para sufrir apoptosis espontánea; sin embargo, no han sido dilucidados los mecanismos involucrados en generar muerte celular programada en los neutrófilos de pacientes VIH positivos. En trabajos previos, hemos explorado algunos eventos asociados con la muerte de los neutrófilos de pacientes infectados. Este artículo tiene como objetivo principal profundizar en los eventos involucrados en la apoptosis espontánea e inducida vía Fas, que pudieran estar implicados en el deterioro de los PMN durante la infección por el VIH

Presencia de Trypanosoma cruzi en tejidos de ratas wistar infectadas experimentalmente y sus fetos / Presnece of Tryoanosoma cruzi in tissues of experimentally infected Wistar rats and their fetuses

Este estudio fue realizado con un grupo de ratas juveniles hembras (Rattus norvegicus) cepa Wistar con 20 días de nacidas y 250 grs. de peso. Cada rata fue inoculada inyectándole por vía intraperitoneal 0.1 mL de la suspensión sanguínea con 1x10 5 tripomastigotes sanguícolas de Trypanosoma cruzi (cepa I/PAS/VE/00/PLANALTO). Los parásitos fueron aislados de Panstrongylus geniculatus, naturalmente infectado y capturado en un área urbana del valle de Caracas, Venezuela y mantenidos en ratones NMRI. A los 10 días post-infección a estas ratas (GI) les fue determinado el ciclo estral y luego fueron apareadas con los machos en una relación 2 hembras/1 macho en cada jaula. Grupos de ratas vírgenes inoculadas con T. cruzi (GII), ratas sanas (GIII) y ratas preñadas (GIV) fueron usadas como controles. La infección por T. cruzi en las ratas de GI reveló los más altos niveles de parasitemias patentes con 12,2 ±1.1 T.cruzi /mm 3 de sangre a los 18,24 y 34 días post-infección con 6,12 y 20 días de gestación respectivamente, al compararla con el GII. Los títulos de anticuerpos específicos anti-T. cruzi fueron mayores en el grupo de ratas gestantes e infectadas con T. cruzi, en comparación con las vírgenes infectadas, representados por 1:512 y 1:2048 a los 19 y 20 días post-infección respectivamente. El 33% de las muestras de líquido amniótico de las ratas del GI, desarrollaron formas flageladas de T. cruzi en el medio de cultivo NNN. El estudio histopatológico de los cortes de 6 µ de espesor coloreados con hematoxilina y eosina del corazón fetal (CF) obtenidos de 2 fetos de ratas del GI con 34 días de infección, reveló nidos de amastigotes en el tejido cardíaco. En las placentas de las ratas del GI se observó una placentitis caracterizada por intenso infiltrado inflamatorio de células mononucleares y polimorfonucleares con predominio de neutró filos.

Estandarización del método para medir el efecto diferencial de los antibióticos antraciclínicos (ATC) doxorubicina y 4'epi doxorubicina sobre plásmido y/o cromosoma bacteriano in vivo / Standarized of the method for to measure the effect diferential of the anthacycline antibiotics (ATC) doxorubinic or 4'epi doxorubicin above plasmic and cromosome bacteriane in vitro

Los antibióticos antraciclínicos (ATC) se utilizan en la terapéutica como antineoplásicos ya que actúan intercalándose entre las bases apareadas del ADN, modificando su estructura y conformación y afectando a las polimerasas y topoisomerasas. En el presente trabajo se intenta demostrar que la resistencia a antibióticos, cuando ésta se encuentra modificada por un plásmido, puede ser alterada por la presencia de ATC. La cepa bacteriana DH5 alfa/pUC19 se cultivo en medio tripticasa soya y luego se colocó en ausencia y presencia de ampicilina (como presión selectiva) y de una ATC (Doxorubicina a 4'epi Doxorubicina). El efecto se puso en evidencia por cuantificación del crecimiento y por evaluación del color en placas con X-gal. Los resultados sugieren que la Doxorubicina tiene un efecto negativo sobre la replicación del plásmido pero afecta positivamente la expresión del mismo. Mientras que 4'-epi Doxorubicina afecta negativamente ambos procesos. Se propone la 4'-epi Doxorubicina como antibiótico para curar plásmidos y así resistencias codificadas en plásmidos, haciéndose la bacteria sensible al antibiótico