Proteogenomic Characterization of Early Intrahepatic Recurrence after Curative-Intent Treatment of Colorectal Liver Metastases.

Clinical and pathological factors are insufficient to accurately identify patients at risk of early recurrence after curative-intent treatment of colorectal liver metastases (CRLM). This study aimed to identify candidate prognostic proteogenomic biomarkers for early intrahepatic recurrence after curative-intent resection of CRLM. Patients diagnosed with intrahepatic recurrence within 6 months of liver resection were categorized as the "early recurrence" group, while those who achieved a recurrence-free status for 10 years were designated as "durable remission". Comprehensive genomic and proteomic profiling of fresh frozen samples from these prognostically distinct groups was performed using the TruSight Oncology 500 assay and label-free data-dependent acquisition liquid chromatography-mass spectrometry. Genetic alterations were identified in 117 of the 523 profiled genes in patients with early recurrence. The most common somatic mutations linked to early recurrence were TP53 (88%), APC (71%), KRAS (38%), and SMAD4 (21%). SMAD4 alterations were absent in samples from patients with a durable remission. Calponin-2, versican core protein, glutathione peroxidase 3, fibulin-5, and amyloid-ß precursor protein were upregulated more than 2-fold in early recurrence. Exploratory analysis of these proteogenomic biomarkers suggests that SMAD4, calponin-2, and glutathione peroxidase 3 may have the potential to predict early recurrence, enabling improved prognostication and precision oncology in CRLM.

Development of a lumbar puncture virtual simulator for medical students training: A preliminary evaluation.

BACKGROUND: Lumbar puncture is an essential medical procedure whose objective is to obtain cerebrospinal fluid. Lumbar puncture is considered a complex procedure, mainly for novice residents who suffer from stress and low confidence, which may result in harm to the patient. METHODS: The LPVirSim, has been developed in four stages: i) requirements analysis through user-centred design; ii) prototyping of the virtual environment and the haptic component; iii) preliminary tests with Ph.D. students and physicians using two haptic devices (Omega.7 and Sigma.7); iv) a user study where physicians evaluated the usability and user experience. RESULTS: The LPVirSim integrates non-technical skills and the possibility of representing different patients for training. Usability increased from 61.76 to 68.75 in the preliminary tests to 71.43 in the user study. CONCLUSIONS: All the results showed good usability and demonstrated that the simulator arouses interest and realistically represents a Lumbar puncture, through the force and visual feedback.

A Geospatial Model to Identify Areas Associated with Late- Stage Breast Cancer: A Spatial Epidemiology Approach.

OBJECTIVE: The aim of this study was to show how a geospatial model can be used to identify areas with a higher probability for late-stage breast cancer (BC) diagnoses. METHODS: Our study considered an ecological design. Clinical records at a tertiary care hospital were reviewed in order to obtain the place of residence and stage of the disease, which was classified as early (0-IIA) and late (IIB-IV) and whose diagnoses were made during the 2013-2017 period. Then, they were geolocated to identify the distribution and spatial trend. Subsequently, the pattern of location, i.e. scattered, random and concentrated, was statistically assessed and a geospatial model was elaborated to determine the probability of late diagnoses in the state of Jalisco, Mexico. RESULT: There were 1 954 (N) geolocated BC diagnoses: 58.3% were late. During the five-year period, a southwest-northeast trend was identified, nearly 9.5% of the surface of Jalisco, where 6 out of 10 (n= 751) late- stage diagnoses were concentrated. A concentrated and statistically significant pattern was identified in the southern, central and northern Pacific area of Jalisco, where the geospatial model delimited the places with the highest probability of late clinical stages (p <0.05). CONCLUSION: The geographical differences associated with the late diagnoses of BC suggest it is necessary to adapt and focus the strategies for early detection as an alternative to create a major impact on the population. Reproducible analysis tools were used in other contexts where geolocation data are available to complement public policies and strategies aimed to control BC.

Augmented reality simulation as training model of ventricular puncture: Evidence in the improvement of the quality of punctures.

BACKGROUND: Ventricular puncture is a common procedure in neurosurgery and the first that resident must learn. Ongoing education is critical to improving patient outcomes. However, training at the expense of potential risk to patients warrants new and safer training methods for residents. METHODS: An augmented reality (AR) simulator for the practice of ventricular punctures was designed. It consists of a navigation system with a virtual 3D projection of the anatomy over a 3D-printed patient model. Forty-eight participants from neurosurgery staff performed two free-hand ventricular punctures before and after a training session. RESULTS: Participants achieved enhanced accuracy in reaching the target at the Monro foramen after practicing with the system. Additional metrics revealed significantly better trajectories after the training. CONCLUSION: The study confirms the feasibility of AR as a training tool. This motivates future work towards standardising new educative methodologies in neurosurgery.

Quantification of short-chain fatty acids in human stool samples by LC-MS/MS following derivatization with aniline analogues.

The gut microbiome produces a range of short chain fatty acids (SCFA) crucially linked with diet and nutrition, metabolism, gastrointestinal health and homeostasis. SCFA are primarily measured using gas or liquid chromatography-mass spectrometry (LC/MS) after undergoing chemical derivatization. Here we assess the merits of a derivatization protocol using aniline and two aniline analogues (3-phenoxyaniline and 4-(benzyloxy)aniline) for the targeted LC-MS/MS quantification of nine SCFA (acetic, propionic, butyric, valeric, caproic acid, isobutyric, isovaleric, 2-methylbutyric, and 2-ethylbutyric acid). Evaluation of product ion spectra and optimization of MS detection conditions, provided superior detection sensitivity for 3-phenoxyaniline and 4-(benzyloxy)aniline compared to aniline. We developed a facile SCFA derivatization method using 3-phenoxyaniline under mild reaction conditions which allows for the simultaneous quantification of these SCFA in human stool samples in under eleven minutes using multiple reaction monitoring LC-MS/MS. The method was successfully validated and demonstrates intra- and inter-day accuracy (88.5-103% and 86.0-109%) and precision (CV of 0.55-7.00% and 0.33-9.55%) with recoveries (80.1-87.2% for LLOQ, 88.5-93.0% for ULOQ) and carry-over of (2.68-17.9%). Selectivity, stability and matrix effects were also assessed and satisfied validation criteria. Method applicability was demonstrated by analysing SCFA profiles in DNA-stabilized human stool samples from newly diagnosed colorectal cancer patients prior to surgery. The development of this improved method and its compatibility to measure SCFAs from DNA-stabilized stool will facilitate studies investigating the gut microbiome in health and disease.

Force-Sensorless Identification and Classification of Tissue Biomechanical Parameters for Robot-Assisted Palpation.

The implementation of robotic systems for minimally invasive surgery and medical procedures is an active topic of research in recent years. One of the most common procedures is the palpation of soft tissues to identify their mechanical characteristics. In particular, it is very useful to identify the tissue's stiffness or equivalently its elasticity coefficient. However, this identification relies on the existence of a force sensor or a tactile sensor mounted at the tip of the robot, as well as on measuring the robot velocity. For some applications it would be desirable to identify the biomechanical characteristics of soft tissues without the need for a force/tactile nor velocity sensors. An estimation of such quantities can be obtained by a model-based state observer for which the inputs are only the robot joint positions and its commanded joint torques. The estimated velocities and forces can then be employed for closed-loop force control, force reflection, and mechanical parameters estimation. In this work, a closed-loop force control is proposed based on the estimated contact forces to avoid any tissue damage. Then, the information from the estimated forces and velocities is used in a least squares estimator of the mechanical parameters. Moreover, the estimated biomechanical parameters are employed in a Bayesian classifier to provide further help for the physician to make a diagnosis. We have found that a combination of the parameters of both linear and nonlinear viscoelastic models provide better classification results: 0% misclassifications against 50% when using a linear model, and 3.12% when using only a nonlinear model, for the case in which the samples have very similar mechanical properties.

Public Policies and Programs for the Prevention and Control of Breast Cancer in Latin American Women: Scoping Review.

BACKGROUND: Breast cancer has positioned itself worldwide as one of the main public health problems, especially in Latin America. In some countries, several programs for the prevention and control of breast cancer in women have been developed and implemented on a permanent basis, but there are no public reports on the policies that originated such programs. OBJECTIVE: A scoping review of scientific publications that identify the type, extent, and scope of policies and programs for the prevention and control of breast cancer in Latin American women was performed, and the main results were presented in this paper. METHODS: This scoping review was carried out according to the method by Arksey and O'Malley based on 3 fundamental questions about breast cancer prevention and control policies in Latin America: their type, extent and scope, and reference framework. The search period was from 2000 to 2019, and the search was carried out in the following databases: MEDLINE (PubMed), MEDLINE (EbscoHost), CINAHL (EbscoHost), Academic Search Complete (EbscoHost), ISI Web of Science (Science Citation Index), and Scopus in English, Spanish, and Portuguese, and Scielo, Cochrane, and MEDES-MEDicina in Spanish and Portuguese. Of the 743 studies found, 20 (2.7%) were selected, which were analyzed using descriptive statistics and qualitative content analysis. RESULTS: The selected studies identified several Latin American countries that have generated policies and programs to prevent and control breast cancer in women, focusing mainly on risk communication, prevention and timely detection, effective access to health services, improvement of the screening process, and evaluation of screening programs. Evaluation criteria and greater participation of civil society in policy design and program execution are still lacking. This could undoubtedly help eliminate existing barriers to effective action. CONCLUSIONS: Although several Latin American countries have generated public policies and action programs for the prevention and control of breast cancer, a pending issue is the evaluation of the results to analyze the effectiveness and impact of their implementation given the magnitude of the public health problem it represents and because women and civil society play an important role in its prevention and control. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.2196/12624.

Knowledge, Attitudes, Behavior, and Practices of Self-Breast Examination in Jalisco, Mexico.

The importance of self-breast examination to identify early signs of breast cancer has been widely discussed in scientific literature. We conducted a cross-sectional survey of women aged 18 years and over (n = 547) living in urban and rural areas in the State of Jalisco, Mexico. Survey questions included measures on knowledge, attitudes, behaviors, and practices related to self-breast examination. We compared these measures between women living in urban and rural areas and women aged 18-39 years and 40+ years. Using t-test, we tested the significance of these differentials. Our results indicate that there is no significant difference in knowledge, attitudes, behavior, and practices regarding self-breast examination between women living in urban and in rural areas of Jalisco. However, we found some difference in these measures between women in 18-39 years and 40+ years. While the State of Jalisco has taken significant steps toward promoting significance of cancer prevention, further attention to women in the older cohort is recommended.

Factores relacionados con el estrés postraumático en pacientes con alta médica por la COVID-19 / Factors related to post-traumatic stress in patients with medical discharge due to COVID-19

RESUMEN Introducción: La hospitalización a causa de la COVID-19 puede predisponer a la aparición de posibles secuelas psicológicas a largo plazo. Objetivo: Determinar la relación entre los factores hospitalarios y no hospitalarios con el estrés postraumático en pacientes con alta médica por la COVID-19. Métodos: Estudio de corte transversal y diseño correlacional. La muestra no probabilística estuvo compuesta por 126 participantes con la COVID-19, evaluados mediante un cuestionario autoadministrado y la Escala de Trauma de Davidson. Para el procesamiento de datos se aplicó la prueba ji cuadrado y la V de Cramer como medida de magnitud de efecto. Resultados: El trastorno por estrés postraumático presenta asociaciones moderadas con los factores hospitalarios: tiempo de hospitalización (p< 0,001) (V de Cramer= 0,33), tipo clínico de COVID-19 (p< 0,001) (V de Cramer= 0,49) y soporte ventilatorio invasivo (p< 0,001) (V de Cramer= 0,39); y con los factores no hospitalarios: oxigenoterapia en rehabilitación (p< 0,001) (V de Cramer= 0,33), secuelas neurológicas (p< 0,001) (V de Cramer= 0,41), dificultad respiratoria (p< 0,001) (V de Cramer= 0,53), percepción de discriminación social (p< 0,05) (V de Cramer= 0,29), dificultad para reincorporarse a las actividades diarias (p< 0,001) (V de Cramer= 0,40) y familiares infectados con la COVID-19 (p< 0,001) (V de Cramer= 0,30). Conclusiones: Existen factores, tanto intra como extrahospitalarios, que se relacionan con el trastorno por estrés postraumático luego del alta médica por la COVID-19.

ABSTRACT Introduction: Hospitalization due to COVID-19 can predispose to the appearance of possible long-term psychological sequelae. Objective: To determine the relationship between hospital and non-hospital factors with post-traumatic stress in patients discharged for COVID-19 from a hospital in Peru. Methods: Cross-sectional study and correlational design. The non-probabilistic sample consisted of 126 participants, evaluated through a self-administered questionnaire and the Davidson Trauma Scale. For data processing, the chi-square test and Cramer's V were used as measures of the magnitude of effect. Results: Post-traumatic stress disorder presents moderate associations with hospital factors: hospitalization time (p<0.001) (Cramer's V = 0.33), clinical type of COVID-19 (p<0.001) (Cramer's V = 0 .49) and invasive ventilatory support (p<0.001) (Cramer's V = 0.39); and with non-hospital factors: oxygen therapy in rehabilitation (p<0.001) (Cramer's V = 0.33), neurological sequelae (p<0.001) (Cramer's V = 0.41), respiratory distress (p<0.001) (Cramer's V = 0.53), perception of social discrimination (p<0.05) (Cramer's V = 0.29), difficulty returning to daily activities (p<0.001) (Cramer's V = 0.40) and family members infected with COVID-19 (p<0.001) (Cramer's V = 0.30). Conclusions: There are both in-hospital and out-of-hospital factors associated with post-traumatic stress disorder following discharge from COVID-19.

Tendencia espacio-temporal de detecciones de diabetes mellitus e hipertensión arterial sistémica en usuarios del IMSS, 2004-2019 / Spatio-temporal trend in detections of diabetes mellitus and systematic arterial hypertension in IMSS users, 2004-2019

Introducción: la diabetes mellitus (DM) y las enfermedades del corazón, entre las que se incluye la hipertensión arterial sistémica (HTA), se han posicionado entre las primeras causas de mortalidad en México, lo que plantea retos importantes para las diferentes instituciones de salud. Objetivo: analizar la tendencia espacio-temporal de DM e HTA con base en las detecciones realizadas en unidades de primero y segundo nivel del Instituto Mexicano del Seguro Social (IMSS), durante el periodo 2004-2019. Material y métodos: estudio ecológico en el que se calcularon las tasas de detección de ambos padecimientos por mil derechohabientes según año, trienio y representación. La tendencia espacio-temporal se analizó mediante estadística espacial utilizando Sistemas de Información Geográfica. Resultados: de 2004 a 2019 hubo 9 399 889 y 11 862 069 detecciones en promedio de DM e HTA, respectivamente. Referente al primer padecimiento, la tasa de deteccion osciló de 203.4 (2004) a 384.4 (2019) por mil derechohabientes, cuya tendencia aumentó en Tamaulipas. Mientras que la HTA disminuyó de 1140.2 (2004) a 352 (2019) detecciones por mil derechohabientes en Veracruz Sur y Tamaulipas, respectivamente. Conclusiones: la tendencia espacio-temporal observada puede contribuir a organizar y orientar, según su representación y nivel de atención, los programas institucionales, protocolos de atención, guías de práctica clínica y demás instrumentos de políticia pública disponibles en el IMSS para mejorar la detección oportuna, atención, control y acceso a medicamentos para DM e HTA.

Background: Diabetes Mellitus (DM) and heart diseases, which include Systemic Arterial Hypertension (SAH), have been positioned as the two main causes of mortality in Mexico, which represents important challenges for the different health institutions. Objective: To analyze the spatio-temporal trend of DM and SAH based on the detections made in first and and second level units of the Instituto Mexicano del Seguro Social, during the period 2004-2019. Material and methods: Ecological study in which detection rates of both diseases were calculated per 1,000 persons according to year, triennium and representation. The spatio-temporal trend was analyzed by spatial statistics using Geographic Information Systems. Results: During 2004-2019 therere were 9 399 889 and 11 862 069 detections on average of DM and SAH, respectively. Regarding DM, the detection rate ranged from 203.4 (2004) to 384.4 (2019) per 1000 persons, this trend increased in Tamaulipas. While SAH decreased from 1140.2 (2004) to 352 (2019) per 1000 persons in Veracruz Sur and Tamaulipas, respectively. Conclusions: The observed spatio-temporal trend can contribute to organizing and guiding, according to representation and level of care, institutional programs, integrated care protocols, clinical practice guidelines and other public policy instruments available at the Instituto Mexicano del Seguro Social to improve early detection, care, control and access to medications for DM and SAH.

Cáncer de mama en Jalisco. Análisis espacial de la mortalidad en 2010-2017 / Breast cancer in Jalisco: a spatial analysis of mortality in the 2010-2017 period

Resumen Introducción: En 2017, el INEGI reportó 84 142 defunciones por tumores malignos en México y la Organización Mundial de la Salud indicó que la tasa de mortalidad por cáncer de mama en 2018 fue de 11.2 por 100 mil mujeres. Objetivo: Mostrar la tendencia de la mortalidad por cáncer de mama en mujeres según municipio y región sanitaria de Jalisco en el periodo 2010-2017. Método: Estudio analítico en el que se estimaron tasas estandarizadas de mortalidad y riesgos relativos por municipio de residencia de 3873 mujeres. Se utilizó estadística espacial de dispersión y tendencia central. Resultados: La tasa de mortalidad aumentó de 10.7 a 13.0 por 100 mil mujeres en el periodo 2010-2017. Los valores más altos se encontraron en los municipios de Chapala (21.2) y Guadalajara (19.5), la tasa de mortalidad aumentó en cuatro de cada 10 municipios y el riesgo relativo fue hasta 50 veces mayor en algunos del occidente y centro de Jalisco. Conclusiones: Se observó un incremento de 1.0 % anual, aunque territorialmente diferenciado. Los resultados representan una oportunidad para mejorar los procesos de detección y diagnóstico oportunos, así como para garantizar la cobertura de los servicios.

Abstract Introduction: In 2017, INEGI reported 84,142 deaths from malignant tumors in Mexico, while the World Health Organization indicated that the breast cancer mortality rate in 2018 was 11.2 per 100,000 women. Objective: To show the trend of breast cancer mortality in women by municipality and health region of Jalisco in the 2010-2017 period. Method: Analytical study in which standardized mortality rates and relative risks of 3873 women were estimated by municipality of residence. Dispersion and central tendency spatial statistics were used. Results: The mortality rate increased from 10.7 to 13.0 per 100,000 women in the 2010-2017 period. The highest values were found in the municipalities of Chapala (21.2) and Guadalajara (19.5); the mortality rate increased in four out of every 10 municipalities, and relative risk was up to 50-fold higher in some of the western and central Jalisco municipalities. Conclusions: An annual increase of 1.0 % was observed, although it was territorially differentiated. The results represent an opportunity to improve timely detection and diagnostic processes, as well as to guarantee the coverage of services.

Study of the sRNA RsmY involved in the genetic regulation of the synthesis of alginate and alkyl resorcinols in Azotobacter vinelandii.

Azotobacter vineladii is a Gram-negative bacterium that produces alginate and poly-hydroxybutyrate (PHB), two polymers of biotechnological interest. This bacterium has the ability to form desiccation-resistant cysts. In the cyst the membrane phospholipids are replaced with a family of phenolic lipids called alkylresorcinols (ARs). The alginate, PHB, and ARs are controlled by the GacS/A two-component system and the small regulatory RNA (sRNA) RsmZ1, belonging to the Rsm (Csr) regulatory system. The Rsm (Csr) systems usually possess two or more sRNAs, in this regard A. vinelandii is the bacterium with the highest number of rsm-sRNAs. Originally, the presence of two sRNAs of the RsmY family (RsmY1 and RsmY2) was reported, but in a subsequent work it was suggested that they conformed to a single sRNA. In this work we provide genetic evidence confirming that rsmY1 and rsmY2 constitute a single gene. Also, it was established that rsmY mutation decreased alginate and ARs production, but did not affect the PHB synthesis. Transcriptional studies showed that rsmY has its higher expression during the stationary growth phase, and in the absence of RsmZ1, rsmY increases its transcription. Interestingly, rsmY expression was influenced by the carbon source, but its expression did not correlate with alginate production.

Breast cancer in Jalisco: a spatial analysis of mortality in the 2010-2017 period.

INTRODUCTION: In 2017, INEGI reported 84,142 deaths from malignant tumors in Mexico, while the World Health Organization indicated that the breast cancer mortality rate in 2018 was 11.2 per 100,000 women. OBJECTIVE: To show the trend of breast cancer mortality in women by municipality and health region of Jalisco in the 2010-2017 period. METHOD: Analytical study in which standardized mortality rates and relative risks of 3873 women were estimated by municipality of residence. Dispersion and central tendency spatial statistics were used. RESULTS: The mortality rate increased from 10.7 to 13.0 per 100,000 women in the 2010-2017 period. The highest values were found in the municipalities of Chapala (21.2) and Guadalajara (19.5); the mortality rate increased in four out of every 10 municipalities, and relative risk was up to 50-fold higher in some of the western and central Jalisco municipalities. CONCLUSIONS: An annual increase of 1.0 % was observed, although it was territorially differentiated. The results represent an opportunity to improve timely detection and diagnostic processes, as well as to guarantee the coverage of services. INTRODUCCIÓN: En 2017, el INEGI reportó 84 142 defunciones por tumores malignos en México y la Organización Mundial de la Salud indicó que la tasa de mortalidad por cáncer de mama en 2018 fue de 11.2 por 100 mil mujeres. OBJETIVO: Mostrar la tendencia de la mortalidad por cáncer de mama en mujeres según municipio y región sanitaria de Jalisco en el periodo 2010-2017. MÉTODO: Estudio analítico en el que se estimaron tasas estandarizadas de mortalidad y riesgos relativos por municipio de residencia de 3873 mujeres. Se utilizó estadística espacial de dispersión y tendencia central. RESULTADOS: La tasa de mortalidad aumentó de 10.7 a 13.0 por 100 mil mujeres en el periodo 2010-2017. Los valores más altos se encontraron en los municipios de Chapala (21.2) y Guadalajara (19.5), la tasa de mortalidad aumentó en cuatro de cada 10 municipios y el riesgo relativo fue hasta 50 veces mayor en algunos del occidente y centro de Jalisco. CONCLUSIONES: Se observó un incremento de 1.0 % anual, aunque territorialmente diferenciado. Los resultados representan una oportunidad para mejorar los procesos de detección y diagnóstico oportunos, así como para garantizar la cobertura de los servicios.

Virtual reality simulation of robotic transsphenoidal brain tumor resection: Evaluating dynamic motion scaling in a master-slave system.

BACKGROUND: Integrating simulators with robotic surgical procedures could assist in designing and testing of novel robotic control algorithms and further enhance patient-specific pre-operative planning and training for robotic surgeries. METHODS: A virtual reality simulator, developed to perform the transsphenoidal resection of pituitary gland tumours, tested the usability of robotic interfaces and control algorithms. It used position-based dynamics to allow soft-tissue deformation and resection with haptic feedback; dynamic motion scaling control was also incorporated into the simulator. RESULTS: Neurosurgeons and residents performed the surgery under constant and dynamic motion scaling conditions (CMS vs DMS). DMS increased dexterity and reduced the risk of damage to healthy brain tissue. Post-experimental questionnaires indicated that the system was well-evaluated by experts. CONCLUSION: The simulator was intuitively and realistically operated. It increased the safety and accuracy of the procedure without affecting intervention time. Future research can investigate incorporating this simulation into a real micro-surgical robotic system.

The GacS/A-RsmA Signal Transduction Pathway Controls the Synthesis of Alkylresorcinol Lipids that Replace Membrane Phospholipids during Encystment of Azotobacter vinelandii SW136.

Azotobacter vinelandii is a soil bacterium that undergoes a differentiation process that forms cysts resistant to desiccation. During encystment, a family of alkylresorcinols lipids (ARs) are synthesized and become part of the membrane and are also components of the outer layer covering the cyst, where they play a structural role. The synthesis of ARs in A. vinelandii has been shown to occur by the activity of enzymes encoded in the arsABCD operon. The expression of this operon is activated by ArpR, a LysR-type transcriptional regulator whose transcription occurs during encystment and is dependent on the alternative sigma factor RpoS. In this study, we show that the two component response regulator GacA, the small RNA RsmZ1 and the translational repressor protein RsmA, implicated in the control of the synthesis of other cysts components (i.e., alginate and poly-ß-hydroxybutyrate), are also controlling alkylresorcinol synthesis. This control affects the expression of arsABCD and is exerted through the regulation of arpR expression. We show that RsmA negatively regulates arpR expression by binding its mRNA, repressing its translation. GacA in turn, positively regulates arpR expression through the activation of transcription of RsmZ1, that binds RsmA, counteracting its repressor activity. This regulatory cascade is independent of RpoS. We also show evidence suggesting that GacA exerts an additional regulation on arsABCD expression through an ArpR independent route.

The Role of the ncRNA RgsA in the Oxidative Stress Response and Biofilm Formation in Azotobacter vinelandii.

Azotobacter vinelandii is a soil bacterium that forms desiccation-resistant cysts, and the exopolysaccharide alginate is essential for this process. A. vinelandii also produces alginate under vegetative growth conditions, and this production has biotechnological significance. Poly-ß-hydroxybutyrate (PHB) is another polymer synthetized by A. vinelandii that is of biotechnological interest. The GacS/A two-component signal transduction system plays an important role in regulating alginate production, PHB synthesis, and encystment. GacS/A in turn controls other important regulators such as RpoS and the ncRNAs that belong to the Rsm family. In A. vinelandii, RpoS is necessary for resisting oxidative stress as a result of its control over the expression of the catalase Kat1. In this work, we characterized a new ncRNA in A. vinelandii that is homologous to the P16/RsgA reported in Pseudomonas. We found that the expression of rgsA is regulated by GacA and RpoS and that it was essential for oxidative stress resistance. However, the activity of the catalase Kat1 is unaffected in rgsA mutants. Unlike those reported in Pseudomonas, RgsA in A. vinelandii regulates biofilm formation but not polymer synthesis or the encystment process.

The unphosphorylated EIIA(Ntr) protein represses the synthesis of alkylresorcinols in Azotobacter vinelandii.

Upon encystment induction, Azotobacter vinelandii produces the phenolic lipids alkylresorcinols (ARs) that are structural components of the cysts. The enzymes responsible for the ARs synthesis are encoded in the arsABCD operon, whose expression is activated by ArpR. The transcription of arpR is initiated from an RpoS dependent promoter. The nitrogen-related phosphotransferase system (PTS(Ntr)) is a global regulatory system present in Gram negative bacteria. It comprises the EI(Ntr), NPr and EIIA(Ntr) proteins encoded by ptsP, ptsO and ptsN genes respectively. These proteins participate in a phosphoryl-group transfer from phosphoenolpyruvate to protein EIIA(Ntr) via the phosphotransferases EI(Ntr) and NPr. In A. vinelandii, the non-phosphorylated form of EIIA(Ntr) was previously shown to repress the synthesis of poly-ß-hydroxybutyrate. In this work, we show that PTS(Ntr) also regulates the synthesis of ARs. In a strain that carries unphosphorylated EIIA(Ntr), the expression of arpR was reduced, while synthesis of ARs and transcription of arsA were almost abrogated. The expression of arpR from an RpoS-independent promoter in this strain restored the ARs synthesis. Taken together these results indicate that unphosphorylated EIIA(Ntr) negatively affects activation of arpR transcription by RpoS.

El Campus Virtual de Salud Pública: seis años de formar recursos humanos en México / Virtual Campus of Public Health: six years of human resources education in Mexico

Este trabajo muestra, desde el punto de vista de la normatividad de la Organización Panamericana de la Salud (OPS), el proceso de gestación, la metodología de implementación y los resultados obtenidos de la iniciativa de formación de recursos humanos en salud vía e-learning a través del Campus Virtual de Salud Pública de la Universidad de Guadalajara, México, a seis años de su inicio. Se trata de un informe especial del trabajo realizado por el comité institucional del campus virtual en la región occidental de México para generar un portal de Internet que se ajustara a los lineamientos del Modelo Estratégico establecido por el Nodo México y la OPS para la Región de las Américas. Este Campus Virtual inició sus actividades en el año 2007. Su filosofía es el uso de software libre y la colaboración entre instituciones. El nodo fue implementado en un año y ha logrado capacitar a más de 500 profesionales de la salud a través de cursos virtuales, su plataforma educativa y un repositorio de recursos virtuales de aprendizaje con interoperabilidad con los repositorios de México y de la Región de las Américas. El comité del Campus Virtual de la Universidad de Guadalajara ha intentado respetar lo más posible al modelo propuesto, lo que ha permitido cumplir la mayoría de los objetivos fijados en el plan de trabajo inicial, aunque ha enfrentado una serie de dificultades administrativas y de motivación de sus integrantes.

This paper discusses the gestation process, implementation methodology, and results obtained from the initiative to use e-learning to train human resources for health, six years after the launch of the Virtual Campus of Public Health of the University of Guadalajara (Mexico); the discussion is framed by Pan American Health Organization (PAHO) standards and practices. This is a special report on the work done by the institutional committee of the Virtual Campus in western Mexico to create an Internet portal that follows the guidelines of the strategic model established by Nodo México and PAHO for the Region of the Americas. This Virtual Campus began its activities in 2007, on the basis of the use of free software and institutional collaboration. Since the initial year of implementation of the node, over 500 health professionals have been trained using virtual courses, the node's educational platform, and a repository of virtual learning resources that are interoperable with other repositories in Mexico and the Region of the Americas. The University of Guadalajara Virtual Campus committee has followed the proposed model as much as possible, thereby achieving most of the goals set in the initial work plan, despite a number of administrative challenges and the difficulty of motivating committee members.

A small heat-shock protein (Hsp20) regulated by RpoS is essential for cyst desiccation resistance in Azotobacter vinelandii.

In Azotobacter vinelandii, a cyst-forming bacterium, the alternative sigma factor RpoS is essential to the formation of cysts resistant to desiccation and to synthesis of the cyst-specific lipids, alkylresorcinols. In this study, we carried out a proteome analysis of vegetative cells and cysts of A. vinelandii strain AEIV and its rpoS mutant derivative AErpoS. This analysis allowed us to identify a small heat-shock protein, Hsp20, as one of the most abundant proteins of cysts regulated by RpoS. Inactivation of hsp20 did not affect the synthesis of alkylresorcinols or the formation of cysts with WT morphology; however, the cysts formed by the hsp20 mutant strain were unable to resist desiccation. We also demonstrated that expression of hsp20 from an RpoS-independent promoter in the AErpoS mutant strain is not enough to restore the phenotype of resistance to desiccation. These results indicate that Hsp20 is essential for the resistance to desiccation of A. vinelandii cysts, probably by preventing the aggregation of proteins caused by the lack of water. To our knowledge, this is the first report of a small heat-shock protein that is essential for desiccation resistance in bacteria.