Caracterización epidemiológica de pacientes con Covid-19 en el Hospital Clínico Universidad de Chile / Epidemiological characterization of patients with Covid-19 in the Hospital Clínico Universidad de Chile

Purpose: Characterize Covid-19 patients diagnosed at the University of Chile Clinical Hospital (HCUCH) during the first 12 epidemiological weeks of the pandemia. Method: Retrospective, case series study of 1372 patients with Covid-19, from march 15 to may 23, 2020, with a follow-up of 3 months. The demographic and epidemiological characteristics were analyzed. Results: Of the 1372 patients, 19,9% were admitted to hospital and 25,18% of them were hospitalized in a critical unit. The median age was 40 years, there were more men than women and 68.5% was Chilean. 80,8% had FONASA as a health insurance. A lethality of 2% was observed. Half of the patients remained hospitalized in a critical unit on day 28. (AU)

[Antimicrobial susceptibility in Chile 2012]. / Susceptibilidad antimicrobiana en Chile 2012.

Bacteria antimicrobial resistance is an uncontrolled public health problem that progressively increases its magnitude and complexity. The Grupo Colaborativo de Resistencia, formed by a join of experts that represent 39 Chilean health institutions has been concerned with bacteria antimicrobial susceptibility in our country since 2008. In this document we present in vitro bacterial susceptibility accumulated during year 2012 belonging to 28 national health institutions that represent about 36% of hospital discharges in Chile. We consider of major importance to report periodically bacteria susceptibility so to keep the medical community updated to achieve target the empirical antimicrobial therapies and the control measures and prevention of the dissemination of multiresistant strains.

Susceptibilidad antimicrobiana en Chile 2012 / Antimicrobial susceptibility in Chile 2012

Bacteria antimicrobial resistance is an uncontrolled public health problem that progressively increases its magnitude and complexity. The Grupo Colaborativo de Resistencia, formed by a join of experts that represent 39 Chilean health institutions has been concerned with bacteria antimicrobial susceptibility in our country since 2008. In this document we present in vitro bacterial susceptibility accumulated during year 2012 belonging to 28 national health institutions that represent about 36% of hospital discharges in Chile. We consider of major importance to report periodically bacteria susceptibility so to keep the medical community updated to achieve target the empirical antimicrobial therapies and the control measures and prevention of the dissemination of multiresistant strains.

La resistencia bacteriana es un problema de salud pública que lejos de estar controlado, aumenta en cantidad y complejidad. El Grupo Colaborativo de Resistencia, es un conjunto de profesionales que representan a 39 establecimientos de salud del país y que se ha ocupado desde 2008 de recolectar información sobre la susceptibilidad antimicrobiana de bacterias en Chile. En este documento se presenta la susceptibilidad in vitro acumulada del año 2012, de 28 establecimientos de salud del país que representan, al menos, 36% de los egresos hospitalarios de Chile. Consideramos de la mayor relevancia reportar periódicamente la susceptibilidad bacteriana de modo de mantener a la comunidad médica actualizada para orientar las terapias empíricas y las medidas de control y prevención de la diseminación de cepas multi-resistentes.

Novel cytochrome P450 genes, CYP6EB1 and CYP6EC1, are over-expressed in acrinathrin-resistant Frankliniella occidentalis (Thysanoptera: Thripidae).

Control of Frankliniella occidentalis (Pergande) is a serious problem for agriculture all over the world because of the limited range of insecticides that are available. Insecticide resistance in F. occidentalis has been reported for all major insecticide groups. Our previous studies showed that cytochrome P450-mediated detoxification is a major mechanism responsible for insecticide resistance in this pest. Degenerate polymerase chain reaction was used to identify P450 genes that might be involved in acrinathrin resistance, in a laboratory population of F. occidentalis. Associated sequences were classified as belonging to the CYP4 and CYP6 families. Real-time quantitative polymerase chain reaction analyses revealed that two genes, CYP6EB1 and CYP6EC1, were over-expressed in adults and L2 larvae of the resistant population, when compared with the susceptible population, suggesting their possible involvement in resistance to acrinathrin.

[Update of the consensus document on ventilator-associated pneumonia: part I. Diagnostic aspects]. / Actualización del Consenso "Neumonía asociada a ventilación mecánica" Primera parte: Aspectos diagnósticos.

The best strategy to resolve the diagnosis of ventilator-associated pneumonia (VAP) is unsettled, and periodic reviews of new evidence are necessary. An update was performed to renew the 2001 recommendations on the diagnosis of this condition by The Chilean Society of Infectious Diseases. The main proposals are: to incorpórate a microbiology-based strategy when there is a suspicion of VAP to gather local epidemiologic data and design appropriate empirical therapy for next cases, and to apply a non-invasive approach such as an endotracheal aspirate or mini-bronchoalveolar lavage, to facilitate accessibility and lower costs. There is no advantage on survival using either quantitative or qualitative cultures for VAP and a definite recommendation cannot be issued. Nonetheless, quantitative cultures are more specific and could facilitate to reject the diagnosis, look for other alternatives, and avoid unnecessary antibiotics. Biomarkers to assist VAP diagnosis are not recommended due to their poor performance. However, serial procalcitonin determinations have been useful to decrease antibiotic use in critical care patients and this biomarker has a better diagnostic yield than C reactive protein in this setting. This consensus also recommends discriminating VAP from ventilator-associated tracheobronchitis (VAT). The latter represents a sepárate entity characterized by an inflammatory response with purulent tracheal secretions but without new pulmonary infiltrates. Although preliminary data supports a beneficial effect of antibiotics to treat this condition, evidence is limited yet, and both conditions deserve to be discriminated (VAP versus VAT).

[Results of antimicrobial susceptibility surveillance in Chile: consolidating a network]. / Resultados de la vigilancia de susceptibilidad antimicrobiana en Chile: Consolidando una red.

Antimicrobial resistance is an increasing public health issue. Creation of surveillance networks is a matter of major importance for antimicrobial resistance understanding and monitoring. Also, they contribute to design actions for controlling its appearance and dissemination. In 2007 a colaborative group in antimicrobial resistance was formed, representing several health institutions across the country. In this paper we report the results of 2009 surveillance with emphasis in its interpretation, limitations and future perspectives.

Actualización del Consenso "Neumonía asociada a ventilación mecánica" Primera parte: Aspectos diagnósticos / Update of the consensus document on ventilator-associated pneumonia: Part I. Diagnostic aspects

The best strategy to resolve the diagnosis of ventilator-associated pneumonia (VAP) is unsettled, and periodic reviews of new evidence are necessary. An update was performed to renew the 2001 recommendations on the diagnosis of this condition by The Chilean Society of Infectious Diseases. The main proposals are: to incorpórate a microbiology-based strategy when there is a suspicion of VAP to gather local epidemiologic data and design appropriate empirical therapy for next cases, and to apply a non-invasive approach such as an endotracheal aspirate or mini-bronchoalveolar lavage, to facilitate accessibility and lower costs. There is no advantage on survival using either quantitative or qualitative cultures for VAP and a definite recommendation cannot be issued. Nonetheless, quantitative cultures are more specific and could facilitate to reject the diagnosis, look for other alternatives, and avoid unnecessary antibiotics. Biomarkers to assist VAP diagnosis are not recommended due to their poor performance. However, serial procalcitonin determinations have been useful to decrease antibiotic use in critical care patients and this biomarker has a better diagnostic yield than C reactive protein in this setting. This consensus also recommends discriminating VAP from ventilator-associated tracheobronchitis (VAT). The latter represents a sepárate entity characterized by an inflammatory response with purulent tracheal secretions but without new pulmonary infiltrates. Although preliminary data supports a beneficial effect of antibiotics to treat this condition, evidence is limited yet, and both conditions deserve to be discriminated (VAP versus VAT).

La estrategia óptima para diagnosticar pacientes con neumonía asociada a ventilación mecánica (NAVM), aún no ha sido definida y es necesario revisar periódicamente nueva evidencia acumulada. Se presenta en este documento una actualización del consenso desarrollado el 2001 sobre diagnóstico de NAVM organizado por la Sociedad Chilena de Infectología. Las principales recomendaciones actuales son: incorporar una estrategia basada en un enfoque microbiológico, cuando exista sospecha de NAVM, para recolectar datos epidemiológicos y así diseñar esquemas antimicrobianos apropiados para los futuros casos, y aplicar sistemas no invasores de estudio, los que facilitan su acceso y permiten reducir costos. Debido a que no existen ventajas en la sobrevida de los pacientes cuando se escogen estrategias de cultivos cuantitativos sobre los no cuantitativos, no se puede recomendar una modalidad sobre la otra. Sin embargo, los cultivos cuantitativos son más específicos y facilitan descartar el diagnóstico, busear otras alternativas y evitar el uso innecesario de antimicrobianos. No se recomienda el uso de bio-marcadores para apoyar el diagnóstico de N AVM debido a su bajo rendimiento. No obstante, el uso de determinaciones seriadas de procalcitonina ha sido útil para limitar el consumo de antimicrobianos en pacientes críticos y tiene un mejor rendimiento diagnóstico respecto a la proteína C reactiva. El consenso recomienda también discriminar los casos de traqueo-bronquitis asociada a VM que representa una entidad separada con un proceso inflamatorio, incluyendo secreciones purulentas pero sin nuevos infiltrados radiológicos. Aunque la información disponible apoya el beneficio de los antimicrobianos para tratar esta última condición, la evidencia es todavía parcial y ambas condiciones deben ser entendidas por separado.

Resultados de la vigilancia de susceptibilidad antimicrobiana en Chile: Consolidando una red / Results of antimicrobial susceptibility surveillance in Chile: Consolidating a network

La resistencia antimicrobiana es un problema de salud pública en aumento. La generación de redes de vigilancia es una necesidad para la correcta comprensión y seguimiento de este fenómeno, además de ayudar a orientar las medidas para el control de su aparición y diseminación. En Chile, desde el año 2007 se constituyó un grupo colaborativo de resistencia antimicrobiana de centros de salud de varias regiones, que ha generado información respecto a la frecuencia de resistencia antimicrobiana de distintas especies bacterianas. En este artículo se presentan los resultados de la vigilancia del año 2009, con énfasis en su interpretación, limitaciones y perspectivas a futuro.

Antimicrobial resistance is an increasing public health issue. Creation of surveillance networks is a matter of major importance for antimicrobial resistance understanding and monitoring. Also, they contribute to design actions for controlling its appearance and dissemination. In 2007 a colaborative group in antimicrobial resistance was formed, representing several health institutions across the country. In this paper we report the results of 2009 surveillance with emphasis in its interpretation, limitations and future perspectives.

Decrease in oxidative stress and histological changes induced by physical exercise calibrated in rats with osteoarthritis induced by monosodium iodoacetate.

OBJECTIVE: The purpose of this study was to evaluate the effects of impact exercise on the joint cartilage of rats with osteoarthritis (OA) induced by monosodium iodoacetate (MIA). METHODS: Eighteen male rats were divided into three groups of six animals each: control, OA, and OA plus exercise (OAE). The OAE group trained on a treadmill for 8 weeks. Afterward, the right joints of the animals were washed with saline solution and joint lavage was used for biochemical analyses of myeloperoxidase (MPO) and enzyme superoxide dismutase (SOD) activities and total thiol content. The same limb provided samples of the articular capsule for analyses of MPO activity and total thiol content. The left joint was used for histological analysis. RESULTS: Our results indicate that MPO activity was increased in both OA groups in the lavage as well as the articular capsule, regardless of exercise status. SOD activity was increased in animals with OA, especially in the animals that had run on the treadmill. On the other hand, thiol content in the articular capsule and joint lavage decreased in the OA group, while the OAE group had values similar to those of the control group. The histological data indicate that animals that were submitted to running exercise showed a higher preservation rate of proteoglycan content in the superficial and intermediate areas of the joint cartilage. CONCLUSION: Our results show that physical training contributes to the preservation of joint cartilage in animals with OA and to increase the defense mechanism against oxidative stress.

[Multicenter study on the monitoring of in vitro susceptibility to tigeeyeline in Santiago, Chile]. / Estudio multicéntrico de la vigilancia de la susceptibilidad in vitro a tigeciclina en Santiago de Chile.

The objective of this multicenter study was to determine tigecycline susceptibility rates, measured by agar diffusion, in nine hospitals in Santiago and to compare these rates with other antimicrobials. Each center studied 20 strains per month. All intermediate and fully resistant strains as well as 10% of susceptibile strains were also studied by the broth microdilution method. Overall, 2301 strains were studied displaying the following susceptibility rates for tigecycline: 100% for Streptococcus sp, Enterococcus sp, and E. coli respectively, 99.8% for Staphylococcus sp, 93% for Klebsiella and 80% for Acinetobacter baumarmii. For Proteus, Providencia and Morganella the susceptibility rates were 4%. For cefotaxime-resistant Klebsiella and imipenem-resistant A. baumarmii susceptibility rates were 95% and 80% respectively. The agar diffusion and broth dilution method were 100% concordant for tigecycline susceptible strains but only 27% for resistant or intermediate strains represented mostly by Acinetobacter baumannii. The majority of these strains (57/59) proved to be susceptible after retesting. The great majority (96,6%) of strains tested from nine Chilean hospitals proved to be susceptible to tigecycline with exception for Proteus, Providencia and Morganella (66% resistance). Using the agar diffusion method for measuring tigecycline susceptibility to A. baumannii may be misleading.

Estudio multicéntrico de la vigilancia de la susceptibilidad in vitro a tigeciclina en Santiago de Chile / Multicenter study on the monitoring of in vitro susceptibility to tigeeyeline in Santiago, Chile

The objective of this multicenter study was to determine tigeeyeline susceptibility rates, measured by agar diffusion, in nine hospitals in Santiago and to compare these rates with other antimicrobials. Each center studied 20 strains per month. All intermedíate and fully resistant strains as well as 10 percent of susceptibile strains were also studied by the broth microdilution method. Overall, 2301 strains were studied displaying the foliowing susceptibility rates for tigeeyeline: 100 percent for Streptococcus sp, Enterococcus sp, and E. coli respectively, 99.8 percent for Staphylococcus sp, 93 percent for Klebsiella and 80 percent for Acinetobacter baumarmii. For Proteus, Providencia and Morganella the susceptibility rates were 4 percent. For cefotaxime-resistant Klebsiella and imipenem-resistant A. baumarmii susceptibility rates were 95 percent and 80 percent respectively. The agar diffusion and broth dilution method were 100 percent concordant for tigeeyeline susceptible strains but only 27 percent for resistant or intermedíate strains represented mostly by Acinetobacter baumannii. The majority of these strains (57/59) proved to be susceptible after retesting. The great majority (96,6 percent) of strains tested from nine Chilean hospitals proved to be susceptible to tigeeyeline with exception for Proteus, Providencia and Morganella (66 percent resistance). Using the agar diffusion method for measuring tigeeyeline susceptibility to A. baumannii may be misleading.

Para conocer la susceptibilidad a tigeciclina por difusión en agar en nueve hospitales de Santiago y comparar la susceptibilidad con otros antimicrobianos, se diseñó este estudio multicéntrico. Cada centro estudió 20 cepas mensualmente. Las intermedias, resistentes y 10 por cientoo de las susceptibles se re-testearon y estudiaron por microdilución en caldo. Se incluyeron 2.304 cepas. Fueron susceptibles a tigeciclina Strep-tococcus sp (100 por cientoo), Enterococcus sp (100 por ciento), E. coli (100 por cientoo), Staphylococcus sp (99,8 por ciento), Klebsiella pneumoniae (93 por ciento) y Acinetobacter baumannii (80 por ciento). En Proteus, Providencia y Morganella la susceptibilidad fue 4 por cientoo. Klebsiella resistente a cefotaxima y Acinetobacter resistente a imipenem, 95 por cientoo y 80 por cientoo fueron susceptibles a tigeciclina, respectivamente. La concordancia en cepas susceptibles y en las enviadas como resistentes o intermedias (A. baumannii) fue 100 por cientoo y 27 por cientoo respectivamente. El re-testeo confirmó que la mayoría eran susceptibles. Los patrones de susceptibilidad bacteriana muestran muy buena actividad in vitro a tigeciclina. La resistencia in vitro de A. baumannii por difusión en agar debe interpretarse con precaución.

[Tuberculosis in health care workers from a public health service in Santiago, Chile]. / Tuberculosis en el personal de salud del Servicio de Salud Metropolitano Sur de Santiago, Chile.

OBJECTIVE: To evalúate the risk of tuberculosis (TBC) among health care workers (HCW) of the Southern Metropolitan Health Service (SMHS) of Santiago, Chile. METHOD: A retrospective study using records of patients receiving TBC treatment in the SMHS from 2001 to 2006 was performed, in which HCW were identified. Total population of HCWs at risk was calculated using annual records of personnel hired at the SMHS. Data on TBC cases and rates were compared against data of the SMSH and hazard ratio (HR) and confidence intervals obtained. RESULTS: Fourteen cases were identified, predominantly among auxiliary personnel (n: 4, 35.7%), nursing staff and ambulance drivers (n: 2, 14.3%) each). Cases occurred in personnel from 41.7% of hospitals and 10.3% of ambulatory care centers within the SMHS and 92.2% involved personnel with direct patient care or contact. Pulmonary localization was seen in 11 (78.6%), and more than half (57.2%) had a positive sputum stain or culture. All cases initiated treatment, but 1 abandoned it and other died of liver failure associated to cirrhosis (7.1% each). Between 2003 and 2006, the annual rate of TBC among HCW ranged between 0 and 79 per 100.000, and during 2004 it was higher than the rate observed in SMHS (Hazard ratio 4.56; IC(95): 1.83-10.62). [corrected] CONCLUSIONS: Despite TBC rate decline in Chile, this disease still represents a significant occupational risk for HCW. Notably, more than half of cases among HCWs are contagious, and despite treatment, some have a lethal evolution.

Tuberculosis en el personal de salud del Servicio de Salud Metropolitano Sur de Santiago, Chile / Tuberculosis in health care workers from a public health service in Santiago, Chile

Objective: To evalúate the risk of tuberculosis (TBC) among health care workers (HCW) of the Southern Metropolitan Health Service (SMHS) of Santiago, Chile. Method: A retrospective study using records of patients receiving TBC treatment in the SMHS from 2001 to 2006 was performed, in which HCW were identified. Total population of HCWs at risk was calculated using annual records of personnel hired at the SMHS. Data on TBC cases and rates were compared against data of the SMSH and hazard ratio (HR) and confidence intervals obtained. Results: Fourteen cases were identified, predominantly among auxiliary personnel (n: 4, 35.7 percent), nursing staff and ambulance drivers (n: 2, 14.3 percent) each). Cases occurred in personnel from 41.7 percent of hospitals and 10.3 percent of ambulatory care centers within the SMHS and 92.2 percent involved personnel with direct patient care or contact. Pulmonary localization was seen in 11 (78.6 percent), and more than half (57.2 percent) had a positive sputum stain or culture. All cases initiated treatment, but 1 abandoned it and other died of liver failure associated to cirrhosis (7.1 percent each). Between 2003 and 2006, the annual rate of TBC among HCW ranged between 0 and 79 per 100.000, and during 2004 it -10.62). Conclusions: Despite TBC rate decline in Chile, this disease still represents a significant occupational risk for HCW. Notably, more than half of cases among HCWs are contagious, and despite treatment, some have a lethal evolution.

Objetivo: Evaluar el riesgo de tuberculosis (TBC) clínica a través de un estudio retrospectivo sobre la razón de prevalencia de TBC entre el personal de salud (PS) del Servicio de Salud Metropolitano Sur de la Región Metropolitana (SSMS) y la población de la misma zona. Método: Los casos entre el PS y el resto del SSMS, junto a la población total y la dotación del PS, se obtuvieron de los registros existentes en el propio SSMS (2001-2006). Resultados: Se identificaron 14 casos, afectando predominantemente a técnicos paramédicos (35,7 por ciento), enfermeros y conductores de ambulancia (14,3 por ciento) cada uno). El 92,9 por ciento de los afectados laboraba en el área clínica. Los casos se presentaron entre el PS de hospitales y consultorios. Los afectados involucraban al 41,7 por ciento del total de hospitales y a 10,3 por ciento de los centros de atención primaria. La localización fue predominantemente pulmonar (78,6 por ciento) y más de la mitad tenía frotis o cultivo de expectoración positivo (57,2 por ciento). Todos los casos iniciaron tratamiento, 12 lo completaron con éxito (85,7 por ciento), uno lo abandonó y el restante falleció por falla hepática asociada a cirrosis (7,1 por ciento cada uno). La tasa entre el PS varió entre 0 y 79 casos por 100.000 y el año 2004 fue significativamente superior al valor registrado en el SSMS (razón de nesgo 4,56; IC95: 1,83 -10,62). Conclusiones: A pesar de la declinación de la TBC en Chile, aún representa un riesgo ocupacional para el PS. Notablemente, más de la mitad de los casos son bacilíferos y algunos casos tienen una evolución letal.

[Tuberculosis in healthcare workers]. / Tuberculosis en el personal de salud.

Tuberculosis (TB) is an occupational risk hazard that explains 5 to 5.361 additional cases of TB per 100.000 individuals among healthcare workers (HCW) in relation to general population in developing countries. For each clinical case a number of additional infections are occurring, that can be detected by tuberculin skin test conversion among non-BCG vaccinated HCW or by interferon-gamma testing. Risk factors for HCW infection include number of TB patients examined, job characteristics and place of work, delay in diagnostic suspicion, patients with multidrug resistant strains, limited access to appropriate ventilation systems, non-compliance with aerosol dissemination precautions, immune suppressed and/or malnourished HCW. Molecular studies suggest that only 32 to 42% of TB cases among HCW are related to occupational exposure. Useful measures to prevent occupational TB acquisition include a number of administrative-, infrastructure- and personal-related measures that have proven to be successful in reducing occurrence of new infections including clinical TB cases among HCW. In Chile, two official government sponsored guidelines are currently available for preventing TB infection among HCW, issued by the national TBC Control Program and by the National Nosocomial infection Control Program. Major differences in recommendations between these guidelines indicate that an update is urgently needed.

Tuberculosis en el personal de salud / Tuberculosis in healthcare workers

Tuberculosis (TB) is an occupational risk hazard that explains 5 to 5.361 additional cases of TB per 100.000 individuals among healthcare workers (HCW) in relation to general population in developing countries. For each clinical case a number of additional infections are occurring, that can be detected by tuberculin skin test conversion among non-BCG vaccinated HCW or by interferon-gamma testing. Risk factors for HCW infection include number of TB patients examined, job characteristics and place of work, delay in diagnostic suspicion, patients with multidrug resistant strains, limited access to appropriate ventilation systems, non-compliance with aerosol dissemination precautions, immune suppressed and/or malnourished HCW. Molecular studies suggest that only 32 to 42 percent of TB cases among HCW are related to occupational exposure. Useful measures to prevent occupational TB acquisition include a number of administrative-, infrastructure- and personal-related measures that have proven to be successful in reducing occurrence of new infections including clinical TB cases among HCW. In Chile, two official government sponsored guidelines are currently available for preventing TB infection among HCW, issued by the national TBC Control Program and by the National Nosocomial infection Control Program. Major differences in recommendations between these guidelines indicate that an update is urgently needed.

La tuberculosis (TBC) es un riesgo ocupacional que explica entre 5 y 5.361 casos por 100.000 personas en el personal de salud (PS) por sobre la población general en países en vías de desarrollo. Cada caso clínico implica que han ocurrido muchos casos de infección. Esta infección puede ser detectada por la prueba de conversión de tuberculina entre personas no vacunadas o por prueba de liberación de gama interferón. Los factores de riesgo incluyen la frecuencia de pacientes con TBC atendidos, la función y lugar de trabajo del PS, retraso en la sospecha diagnóstica, atención de pacientes con cepas multi-resistentes, sistemas de ventilación limitados, falta de aplicación de precauciones por aerosoles y PS con inmunosupresión o desnutrición. Los estudios moleculares han permitido aclarar que sólo 32 a 42 por ciento de los casos en el PS responde a adquisición ocupacional. Las medidas útiles para prevenir este riesgo incluyen un conjunto de disposiciones administrativas, de infraestructura y precauciones en el personal que han permitido reducir el riesgo de infección, y en ocasiones el de TBC clínica, en el PS. En Chile existen actualmente dos normas reguladoras sobre la materia, una del Programa Nacional de la TBC y el otro del Programa de Infecciones Intrahospitalarias, las que difieren en algunos aspectos sustantivos y que ameritan una revisión.

Freeze-thawing induces alterations in the protamine-1/DNA overall structure in boar sperm.

The main aim of this work was to test the effects that freeze-thawing could have on the overall nuclear structure of boar sperm. This was done by analyzing both the DNA fragmentation and the protamine-1-DNA interaction of the boar-sperm nucleus. Our results indicate that freezing-thawing did not induce a significant degree of DNA fragmentation, as manifested through both the Sperm-Sus-Halomax stain and a random primed analysis prior to partial DNA digestion with enzymes BamHI-HinDIII. On the other hand, freeze-thawing induced significant changes in the protamine-1-DNA interaction, as revealed through both Western blot analysis and immunocytochemistry for protamine-1. These alterations caused, in turn, significant changes in the overall nuclear structure of boar sperm after thawing. Protamine-1-DNA alterations started to be apparent during the cooling phase of the freeze-thawing protocol. These results imply that one of the alterations that may be responsible for the loss of fertilizing ability of boar sperm after freeze-thawing may be an alteration in the correct formation of the overall nuclear structure, which, in turn, would induce alterations in the correct formation of the first nuclear structure after oocyte penetration.

Epidemiología clínica y molecular de las infecciones por Shigella spp en niños de la Región Metropolitana durante el verano 2004-2005 / Shigella spp Infections In children living In the Metropolitan RegionChile, during summer of 2004-2005

Background: Shigella spp is a frequent cause of diarrhea in children. Antimicrobials decrease the duration of diarrhea and pathogen excretion. However, the increasing resistance limits their therapeutic value. Aim: To study Shigella serotype distribution in the Metropolitan Region in Chile, and its relationship with severity of disease, antimicrobial resistance pattern and clonality. Material and methods: During summer 2004-2005, stool samples from children with diarrhea were collected in Cary Blair transpon medium and cultured. Shigella isolates were serotyped using monoclonal and polyclonal commercial antibodies. In vitro activity of ampicillin, amoxicillin/clavulanic acid, chloramphenicol, cotrimoxazol, nalidixic acid, ciprofloxacin, ceftriaxone and azythromycin was determined by minimal inhibitory concentration (MIC). Clonality was studied by pulsed-field gel electrophoresis (PFGE) using Xbal as restriction enzyme. Results: One hundred thirty nine Shigella strains were isolated (77 S sonnei and 62 S flexneri). S sonnei and S flexneri 2a serotypes were responsible for 95 percent of episodes. Children aged 2-4 years, showed a greater incidence of Shigella infections and 77 percent of episodes were treated on an ambulatory basis. High resistance levels were observed for ampicillin, cotrimoxazole, amoxicillin-clavulanic acid and chloramphenicol (67 percent, 60 percent, 56 percent and 45 percent, respectively). We found 11 resistance patterns and 61,2 percent of strains were multiresistant. There were multiple clones without a strict relationship with resistance patterns. Conclusions: Shigella infections in Metropolitan Region in Chile are associated to a restricted number of serotypes, representing a clonal expansion associated to different antimicrobial resistant patterns.

[Precautions in the care of patients hospitalized with H5N1 avian influenza]. / Precauciones en la atención de pacientes hospitalizados por influenza aviar H5N1.

Several agencies have proposed infection control guidelines for management of patients admitted with the diagnosis of avian influenza. These guidelines aim to prevent transmission from the patient to hospital personnel and other inpatients. The guidelines presented here by the Advisory Committee of Nosocomial Infections have been elaborated for the local medical community after reviewing currently available recommendations. Key recommendations include admission to an isolation ward, cohorting of confirmed cases, hand hygiene with antiseptic solutions, use of N95 type masks, non-sterile disposable gloves and eye protection equipment during examination or when performing aerosols-generating procedures. Use of patient-exclusive clinical instruments, daily disinfection of the hospital ward, implementation of measures to reduce risk of needle stick injuries and eye splashing, and reinforcement of appropriate sampling and transport of blood and other corporal fluids, are also recommended.

Partial purification of tightly bound mitochondrial hexokinase from maize (Zea mays L.) root membranes.

In mammals, hexokinase (HK) is strategically located at the outer membrane of mitochondria bound to the porin protein. The mitochondrial HK is a crucial modulator of apoptosis and reactive oxygen species generation. In plants, these properties related to HK are unknown. In order to better understand the physiological role of non-cytosolic hexokinase (NC-HK) in plants, we developed a purification strategy here described. Crude extract of 400 g of maize roots (230 mg protein) contained a specific activity of 0.042 micromol G6P min(-1) mg PTN(-1). After solubilization with detergent two fractions were obtained by DEAE column chromatography, NC-HK 1 (specific activity = 3.6 micromol G6P min(-1) mg PTN(-1) and protein recovered = 0.7 mg) and NC-HK 2. A major purification (yield = 500-fold) was obtained after passage of NC-HK 1 through the hydrophobic phenyl-Sepharose column. The total amount of protein and activity recovered were 0.04 and 18%, respectively. The NC-HK 1 binds to the hydrophobic phenyl-Sepharose matrix, as observed for rat brain HK. Mild chymotrypsin digestion did not affect adsorption of NC-HK 1 to the hydrophobic column as it does for rat HK I. In contrast to mammal mitochondrial HK, glucose-6-phosphate, clotrimazole or thiopental did not dissociate NC-HK from maize (Zea mays) or rice (Oryza sativa) mitochondrial membranes. These data show that the interaction between maize or rice NC-HK to mitochondria differs from that reported in mammals, where the mitochondrial enzyme can be displaced by modulators or pharmacological agents known to interfere with the enzyme binding properties with the mitochondrial porin protein.