Paxlovid™ reduces the incidence of pneumonia, hospitalization, and death in a cohort of COVID-19 patients from northeast Mexico.

BACKGROUND: Information on Paxlovid™ effectiveness must be monitored and updated in real world scenarios. Our research question was what is the effectiveness of Paxlovid™ in adult patients with COVID-19? Therefore, we investigated the effectiveness of Paxlovid™ on reducing the incidence of pneumonia, hospitalization, and mortality in a cohort of COVID-19 positive adult patients from northeast Mexico. METHODS: A retrospective cohort study of COVID-19 positive adult patients from Nuevo Leon, Mexico from December 2020 to May 2023 (after Omicron BA-5 circulation) was performed. Paxlovid™ use was authorized in September 2022. Therefore, we analyzed effectiveness in patients with confirmed diagnosis who met selection criteria between September 2022 and May 2023 (n = 20,799; 5,673 with and 15,126 without Paxlovid™). RESULTS: The pneumonia (0.1% vs. 0.4%, p < 0.0001), hospitalization (0.1% vs. 1.2%, p < 0.0001), and death rates (0.04% vs. 0.2%, p < 0.0001) were lower in patients with Paxlovid™ treatment independently of age, sex, comorbidity, and COVID-19 and pneumococcal vaccination history. Effectiveness was 88.2%, 95.9% y 91.9% for pneumonia, hospitalization, and death, respectively. CONCLUSIONS: Paxlovid™ reduces the presentation of pneumonia, hospitalization, and death secondary to COVID-19. It is recommended to continue monitoring Paxlovid™ effectiveness, as other SARS-CoV-2 variants continue to emerge.

(p)ppGpp is required for virulence of Shigella flexneri.

Infection by the enteric pathogen Shigella flexneri requires transit through the gastrointestinal tract and invasion of and replication within the cells of the host colonic epithelium. This process exposes the pathogen to a range of diverse microenvironments. Furthermore, the unique composition and physical environment of the eukaryotic cell cytosol represents a stressful environment for S. flexneri, and extensive physiological adaptations are needed for the bacterium to thrive. In this work, we show that disrupting synthesis of the stringent response alarmone (p)ppGpp in S. flexneri diminished expression of key virulence genes, including ipaA, ipaB, ipaC, and icsA, and it reduced bacterial invasion and intercellular spread. Deletion of the (p)ppGpp synthase gene relA alone had no effect on S. flexneri virulence, but disruption of both relA and the (p)ppGpp synthase/hydrolase gene spoT resulted in loss of (p)ppGpp synthesis and virulence. While the relA spoT deletion mutant was able to invade a cultured human epithelial cell monolayer, albeit at reduced levels, it was unable to maintain the infection and spread to adjacent cells, as indicated by loss of plaque formation. Complementation with spoT on a plasmid vector restored plaque formation. Thus, SpoT alone is sufficient to provide the necessary level of (p)ppGpp for virulence. These results indicate that (p)ppGpp is required for S. flexneri virulence and adaptation to the intracellular environment, adding to the repertoire of signaling pathways that affect Shigella pathogenesis.

[Impact of electronic devices used at an early age on language]. / Impacto del uso de dispositivos electrónicos a edad temprana en el lenguaje.

Background: The acquisition of language in infants is largely the result of the process of brain maturation, as well as environmental stimulation. Currently, society is in an era of technology and use of electronic devices from an early age. Objective: The aim of this study was to demonstrate if the amount of time of use of electronic devices in children under 5 years of age affects language development. Methods: An observational, comparative, survey-type study was carried out in 269 infants of both sexes, with an age range of 6 to <60 months. The language development section of the Child Development Scale (EDI) was used. A logistic regression was performed to determine the strength of association between the factors to be studied. Results: 269 participants were included, of which 224 (83.2%) presented their level of neurological maturation, 44 infants (16.4%) presented laged development and one (0.4%) was classified as having developmental delay. It was found that the number of daily hours that an electronic device is used behaved as a risk factor by increasing the risk of delayed language development by 1.37 times for each hour of exposure (OR: 1.37, CI95%: 1.15-1.62). Conclusions: It was shown that a greater number of hours of use of electronic devices is a risk factor for delayed language development in children under 5 years of age. Therefore, it is vital to limit its use in this population.

Introducción: la adquisición del lenguaje en los infantes es, en gran medida, resultado del proceso de maduración cerebral, así como de la estimulación ambiental. En la actualidad, la sociedad se encuentra en una era de tecnología y uso de dispositivos electrónicos desde temprana edad. Objetivo: evaluar el efecto del tiempo de uso de dispositivos electrónicos en los menores de 5 años en el área del lenguaje. Métodos: se realizó un estudio observacional, comparativo, tipo encuesta, en infantes con rango de edad de 6 a < 60 meses de ambos sexos. Se utilizó la sección para medir desarrollo del lenguaje de la Escala de Desarrollo Infantil (EDI). Adicionalmente, se llevó a cabo una regresión logística con el objetivo de determinar la fuerza de asociación entre los factores a estudiar. Resultados: se incluyeron 269 participantes, de los cuales 224 de ellos (83.2%) correspondían a su nivel de maduración neurológica, 44 infantes (16.4%) presentaron rezago en su desarrollo y uno (0.4%) se clasificó con retraso en el desarrollo. Encontramos que el número de horas diarias utilizando algún dispositivo electrónico se comportó como factor de riesgo, aumentando 1.37 veces el riesgo de retraso en el desarrollo del lenguaje por cada hora de exposición (OR: 1.37, IC95%: 1.15-1.62). Conclusiones: un mayor número de horas de uso de los dispositivos electrónicos es factor de riesgo para presentar retraso en el desarrollo del lenguaje en menores de 5 años.

Diagnostic performance of two rapid tests for syphilis screening in people living with HIV in Cali, Colombia.

INTRODUCTION: There is insufficient evidence supporting the use of rapid diagnostic tests (RDTs) for syphilis in people living with HIV (PLWH). We evaluated the diagnostic performance of two commercially available RDTs (Bioline and Determine) in PLWH in Cali, Colombia. METHODS: A cross-sectional field validation study on consecutive adults with confirmed HIV diagnosis attending three outpatient clinics. Both RDTs were performed on capillary blood (CB), obtained by finger prick, and sera, by venipuncture. A combination of treponemal enzyme linked immunosorbent assay (ELISA) and Treponema pallidum haemagglutination assay (TPHA) on serum samples was the reference standard. Rapid plasma reagin (RPR) and clinical criteria were added to define active syphilis. Sensitivity and specificity, predictive values and likelihood ratios (LR) of RDTs were estimated with their corresponding 95% confidence interval (95% CI). Stratified analyses by sample type, patient characteristics, non-treponemal titers, operator and re-training were performed. RESULTS: 244 PLWH were enrolled, of whom 112 (46%) had positive treponemal reference tests and 26/234 (11.1%) had active syphilis. The sensitivities of Bioline on CB and sera were similar (96.4% vs 94.6%, p = 0.6). In contrast, Determine had a lower sensitivity on CB than sera (87.5% vs 99.1%, p<0.001). Sensitivities were lower in PLWH not receiving ART (Bioline 87.1% and Determine 64.5%, p<0.001) and for one of the operators (Bioline 85% and Determine 60%, p<0.001). Specificities of the RDTs were > 95% in most analyses. Predictive values were 90% or higher. For active syphilis, the RDTs showed a similar performance pattern but with decreased specificities. CONCLUSION: The studied RDTs have an excellent performance in PLWH to screen for syphilis and potentially for active syphilis, yet Determine performs better on sera than CB. Patient characteristics and potential difficulties operators may face in acquiring enough blood volume from finger pricks should be considered for the implementation and the interpretation of RDTs.

Antimicrobial Resistance Dynamics in Chilean Shigella sonnei Strains Within Two Decades: Role of Shigella Resistance Locus Pathogenicity Island and Class 1 and Class 2 Integrons.

Shigellosis is an enteric infectious disease in which antibiotic treatment is effective, shortening the duration of symptoms and reducing the excretion of the pathogen into the environment. Shigella spp., the etiologic agent, are considered emerging pathogens with a high public health impact due to the increase and global spread of multidrug-resistant (MDR) strains. Since Shigella resistance phenotype varies worldwide, we present an overview of the resistance phenotypes and associated genetic determinants present in 349 Chilean S. sonnei strains isolated during the periods 1995-1997, 2002-2004, 2008-2009, and 2010-2013. We detected a great variability in antibiotic susceptibility patterns, finding 300 (86%) MDR strains. Mobile genetic elements (MGE), such as plasmids, integrons, and genomic islands, have been associated with the MDR phenotypes. The Shigella resistance locus pathogenicity island (SRL PAI), which encodes for ampicillin, streptomycin, chloramphenicol, and tetracycline resistance genes, was detected by PCR in 100% of the strains isolated in 2008-2009 but was less frequent in isolates from other periods. The presence or absence of SRL PAI was also differentiated by pulsed-field gel electrophoresis. An atypical class 1 integron which harbors the bla OXA-1 -aadA1-IS1 organization was detected as part of SRL PAI. The dfrA14 gene conferring trimethoprim resistance was present in 98.8% of the 2008-2009 isolates, distinguishing them from the SRL-positive strains isolated before that. Thus, it seems an SRL-dfrA14 S. sonnei clone spread during the 2008-2009 period and declined thereafter. Besides these, SRL-negative strains harboring class 2 integrons with or without resistance to nalidixic acid were detected from 2011 onward, suggesting the circulation of another clone. Whole-genome sequencing of selected strains confirmed the results obtained by PCR and phenotypic analysis. It is highlighted that 70.8% of the MDR strains harbored one or more of the MGE evaluated, while 15.2% lacked both SRL PAI and integrons. These results underscore the temporal dynamics of antimicrobial resistance in S. sonnei strains circulating in Chile, mainly determined by the spread of MGE conferring MDR phenotypes. Since shigellosis is endemic in Chile, constant surveillance of antimicrobial resistance phenotypes and their genetic basis is a priority to contribute to public health policies.

Almacenamiento de carbono en sistemas agroforestales en los Llanos Orientales de Colombia / Carbon storage in agroforestry systems in Colombia's Eastern Plains

Introducción: Los cultivos de café, cacao y pasturas para la ganadería son actividades agropecuarias de interés económico en Colombia. Cuando estas actividades se desarrollan bajo sistemas agroforestales (SAF) promueven la conservación e incrementan la fijación de carbono y, por ende, la mitigación del cambio climático. Objetivo: El estudio estimó el almacenamiento de carbono en la biomasa aérea, necromasa y carbono orgánico del suelo bajo SAF con cacao (SAF cacao), SAF con café (café SAF), sistemas silvopastoriles (SSP) y bosque en el municipio de Mesetas, Meta (Colombia). Métodos: Se establecieron 44 parcelas de muestreo, en donde se tomaron medidas dasométricas a individuos con un diámetro del tronco a la altura del pecho (dap) ≥ 2.5 cm (latizales, fustales y fustales grandes), cuyos valores fueron transformados a carbono con modelos de biomasa y una fracción de carbono default. En los tres sistemas agropecuarios, se contó el número de árboles de cacao, café, plantas asociadas y se identificó el tipo de uso (maderable, alimento, combustión). Resultados: El almacenamiento de carbono presentó diferencias significativas (P < 0.0001) entre usos del suelo. La mayor acumulación se encontró en bosque, con 216.6 t C ha-1, superando en 59, 72 y 73 % a SAF cacao, SSP y SAF café, respectivamente. Fabaceae, Lauraceae y Primulaceae presentaron el mayor almacenamiento de carbono. En SAF cacao, la mayor acumulación de carbono fue encontrada en especies para alimento humano; en SAF café y SSP, el mayor almacenamiento fue presentado en las especies maderables. Conclusión: Estos resultados resaltan el potencial de almacenamiento de carbono en los sistemas productivos de mayor importancia en el departamento del Meta, lo cual es importante para el diseño de estrategias que permitan integrar acciones de mitigación de emisiones de gases de efecto invernadero y promover la economía campesina local.

Introduction: Coffee, cocoa crops and pastures for livestock are agricultural activities of economic interest in Colombia. When these activities are developed under agroforestry systems (AFS), they promote conservation and increase carbon fixation and, therefore, climate change mitigation. Objective: The study estimated carbon storage in aboveground biomass, necromass and soil organic carbon under SAF with cocoa (SAF cocoa), SAF with coffee (SAF coffee), silvopastoral systems (SPS) and forest in Mesetas, Meta (Colombia). Methods: Forty-four sampling plots were established, where dasometric measurements were taken from individuals with a trunk diameter at breast height (dbh) ≥ 2.5 cm (saplings, trees and large trees), whose values were transformed to carbon with biomass models and a default carbon fraction. In the three agricultural systems, the number of cocoa and coffee trees and associated plants was counted, and the type of use (timber, food, combustion) was identified. Results: Carbon storage showed significant differences (P < 0.0001) among land uses. The highest accumulation was found in forest, with 216.6 t C ha-1, exceeding in 59, 72 and 73 % to SAF cocoa, SSP and SAF coffee, respectively. The botanical families Fabaceae, Lauraceae and Primulaceae presented the greatest carbon storage. In SAF cocoa, the greatest accumulation of carbon was found in species for human food; in SAF coffee and SSP, the greatest storage was presented by timber species. Conclusion: These results highlight the potential for carbon storage in the most important productive systems in the Meta department, which is important for designing strategies that allow for integrating actions to mitigate greenhouse gas emissions and to promote the local peasant economy.

IurV, Encoded by ORF VCA0231, Is Involved in the Regulation of Iron Uptake Genes in Vibrio cholerae.

The pathogen Vibrio cholerae has multiple iron acquisition systems which allow bacteria to exploit a variety of iron sources across the different environments on which it thrives. The expression of such iron uptake systems is highly regulated, mainly by the master iron homeostasis regulator Fur but also by other mechanisms. Recently, we documented that the expression of many of the iron-responsive genes is also modulated by riboflavin. Among them, the open reading frame VCA0231, repressed both by riboflavin and iron, encodes a putative transcriptional regulator of the AraC/XylS family. Nonetheless, the genes or functions affected by this factor are unknown. In the present study, a series of in silico analyses was performed in order to identify the putative functions associated with the product of VCA0231. The STRING database predicted many iron uptake genes as functional partners for the product of VCA0231. In addition, a genomic neighborhood analysis with the Enzyme Function Initiative tools detected many Pfam families involved in iron homeostasis genetically associated with VCA0231. Moreover, a phylogenetic tree showed that other AraC/XylS members known to regulate siderophore utilization in bacteria clustered together and the product of VCA0231 localized in this cluster. This suggested that the product of VCA0231, here named IurV, is involved in the regulation of iron uptake processes. RNAseq was performed to determine the transcriptional effects of a deletion in VCA0231. A total of 52 genes were overexpressed and 21 genes were downregulated in response to the iurV deletion. Among these, several iron uptake genes and other iron homeostasis-related genes were found. Six gene ontology (GO) functional terms were enriched in the upregulated genes, of which five were related to iron metabolism. The regulatory pattern observed in the transcriptomics of a subset of genes was independently confirmed by quantitative real time PCR analysis. The results indicate that IurV is a novel regulator of the AraC/XylS family involved in the repression of iron uptake genes. Whether this effect is direct or indirect remains to be determined.

Interdependency of regulatory effects of iron and riboflavin in the foodborne pathogen Shigella flexneri determined by integral transcriptomics.

Shigella flexneri is the causative agent of dysentery. For pathogens, iron is a critical micronutrient as its bioavailability is usually low in bacterial niches. This metal is involved in critical physiological processes mainly as a component of important metabolic molecules involved in redox reactions. Usually bacteria respond to fluctuations in iron availability to regulate iron acquisition and other iron-related functions. Recently the close metabolic feedback between iron and riboflavin, another pivotal biological redox agent, began to draw attention in bacteria. This is a widespread biological phenomenon, partly characterized by the coordination of regulatory responses to iron and riboflavin, probably owed to the involvement of these cofactors in common processes. Nonetheless, no systematic analyses to determine the extent of this regulatory effect have been performed in any species. Here, the transcriptomics responses to iron, riboflavin, iron in the presence of riboflavin and riboflavin in the presence of iron were assessed and compared in S. flexneri. The riboflavin regulon had a 43% overlap with the iron regulon. Notably, the presence of riboflavin highly increased the number of iron-responsive genes. Reciprocally, iron drastically changed the pool of riboflavin-responsive genes. Gene ontology (GO) functional terms enrichment analysis showed that biological processes were distinctively enriched for each subgroup of responsive genes. Among the biological processes regulated by iron and riboflavin were iron uptake, amino acids metabolism and electron transfer for ATP synthesis. Thus, iron and riboflavin highly affect the transcriptomics responses induced by each other in S. flexneri. GO terms analysis suggests that iron and riboflavin coordinately regulate specific physiological functions involving redox metabolism.

SRL pathogenicity island contributes to the metabolism of D-aspartate via an aspartate racemase in Shigella flexneri YSH6000.

In recent years, multidrug resistance of Shigella strains associated with genetic elements like pathogenicity islands, have become a public health problem. The Shigella resistance locus pathogenicity island (SRL PAI) of S. flexneri 2a harbors a 16Kbp region that contributes to the multidrug resistance phenotype. However, there is not much information about other functions such as metabolic, physiologic or ecological ones. For that, wild type S. flexneri YSH6000 strain, and its spontaneous SRL PAI mutant, 1363, were used to study the contribution of the island in different growth conditions. Interestingly, when both strains were compared by the Phenotype Microarrays, the ability to metabolize D-aspartic acid as a carbon source was detected in the wild type strain but not in the mutant. When D-aspartate was added to minimal medium with other carbon sources such as mannose or mannitol, the SRL PAI-positive strain was able to metabolize it, while the SRL PAI-negative strain did not. In order to identify the genetic elements responsible for this phenotype, a bioinformatic analysis was performed and two genes belonging to SRL PAI were found: orf8, coding for a putative aspartate racemase, and orf9, coding for a transporter. Thus, it was possible to measure, by an indirect analysis of racemization activity in minimal medium supplemented only with D-aspartate, that YSH6000 strain was able to transform the D-form into L-, while the mutant was impaired to do it. When the orf8-orf9 region from SRL island was transformed into S. flexneri and S. sonnei SRL PAI-negative strains, the phenotype was restored. Although, when single genes were cloned into plasmids, no complementation was observed. Our results strongly suggest that the aspartate racemase and the transporter encoded in the SRL pathogenicity island are important for bacterial survival in environments rich in D-aspartate.

Dynamics of photosynthetic responses in 10 rubber tree (Hevea brasiliensis) clones in Colombian Amazon: Implications for breeding strategies.

The rubber tree [Hevea brasiliensis (Willd. Ex Adr. de Juss.) Muell.-Arg] is the main source of natural rubber in the world. However, in the Amazon region, its production is reduced by biotic and abiotic limitations, which have prompted breeding programs in order to identify desirable agronomic and physiological indicators. The objective of this study was to analyze the temporal dynamics of photosynthetic responses based on the parameters of leaf gas exchange and chlorophyll a fluorescence in 10 rubber tree clones during the immature phase (pre-tapping) in three large-scale clone trials, during daily cycles and under two climatic periods (dry and rainy) in the Caquetá region (Colombian Amazon). The variables A, LT, ΦPSII, ETR and qP were significantly higher in the dry period, where the highest values of PAR, AT and VPD were seen. In San Vicente del Caguán and Florencia, the highest averages were estimated for A, E and gs, as compared with Belén de los Andaquíes. In Florencia, the highest fluorescence parameters of chlorophyll a were recorded. At 9:00 h and 12:00 h, the highest means of A, E, ΦPSII and ETR were observed. The majority of the clones displayed the highest Fv/Fm mean (0.82-0.84) in the dry period. The clones FX 4098, FDR 4575, MDF 180, GU198 and FDR 5788 represent genotypes with the best photosynthetic performance (greater photosynthetic rates and better ability of the photosynthetic apparatus to capture, use and dissipate light energy). These desirable genotypes constitute a promising gene pool for expanding the genetic resource of rubber trees in the Colombian Amazon.

Cumulative acquisition of pathogenicity islands has shaped virulence potential and contributed to the emergence of LEE-negative Shiga toxin-producing Escherichia coli strains.

Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens causing severe gastroenteritis, which may lead to hemolytic uremic syndrome. The Locus of Enterocyte Effacement (LEE), a Pathogenicity Island (PAI), is a major determinant of intestinal epithelium attachment of a group of STEC strains; however, the virulence repertoire of STEC strains lacking LEE, has not been fully characterized. The incidence of LEE-negative STEC strains has increased in several countries, highlighting the relevance of their study. In order to gain insights into the basis for the emergence of LEE-negative STEC strains, we performed a large-scale genomic analysis of 367 strains isolated worldwide from humans, animals, food and the environment. We identified uncharacterized genomic islands, including two PAIs and one Integrative Conjugative Element. Additionally, the Locus of Adhesion and Autoaggregation (LAA) was the most prevalent PAI among LEE-negative strains and we found that it contributes to colonization of the mice intestine. Our comprehensive and rigorous comparative genomic and phylogenetic analyses suggest that the accumulative acquisition of PAIs has played an important, but currently unappreciated role, in the evolution of virulence in these strains. This study provides new knowledge on the pathogenicity of LEE-negative STEC strains and identifies molecular markers for their epidemiological surveillance.

Evaluación tomográfica de la fontanela anterior de pacientes pediátricos en la ciudad de Quito / Tomographic evaluation of the anterior fontanelle in pediatric patients in the Quito city

INTRODUCCIÓN. La evaluación del tamaño y osificación de las suturas craneales pudo determinar alteraciones del desarrollo cerebral. El estudio realizó la evaluación tomográfica del tamaño de la fontanela anterior y determinó el porcentaje de osificación en función de la edad. MATERIALES Y MÉTODOS. Se realizó un estudio retrospectivo, observacional, en el que se evaluó 367 tomografías computarizadas de cráneo en niños y niñas hasta 2 años de edad, desde enero de 2012 hasta agosto de 2015, en cuatro centros de imagen de la ciudad de Quito, Ecuador. RESULTADOS. El tamaño promedio de la fontanela anterior medida en tomografía computarizada con la fórmula de Popich y Smith, fue de 48,43 mm SD (15,15mm) en hombres y 37,36mm SD (13,97mm) en mujeres, en el grupo de edad de 0 a 3 meses, sin diferencia estadística significativa (p=> 0,05). El 8,0% de los pacientes tuvo una fontanela osificada a la edad de 5 meses. La edad media de osificación de la fontanela fue 18 meses. En el grupo de edad de 21 a 24 meses el porcentaje de osificación fue de 82,0%. CONCLUSIÓN. Este estudio proporcionó valores de referencia que detallaron el porcentaje de tamaño y osificación de la fontanela anterior en función de la edad. Existió amplia variabilidad del tamaño medio de la fontanela anterior, lo cual sugiere que el cierre prematuro o tardío podría considerarse como variantes de la normalidad.

INTRODUCTION. The evaluation of the size and ossification of the cranial sutures could determine alterations in brain development. The study performed the tomographic evaluation of the size of the previous source and determined the percentage of ossification in the function of age. MATERIALS AND METHODS. A retrospective, observational study was conducted in which 367 cranial CT scans were evaluated in children up to 2 years of age, from January 2012 to August 2015, in four imaging centers in the city of Quito, Ecuador. RESULTS The average size of the previous source in computed tomography with the formula of Popich and Smith was 48,43 mm SD (1515 mm) in men and 37,36 mm SD (13,97 mm) in women, in the group of age from 0 to 3 months, without significant statistical difference (p=> 0.05). 8,0% of patients had a source after 5 months. The average age of the source of the source was 18 months. In the age group from 21 to 24 months, the percentage of ossification was 82,0%. CONCLUSIONS This study provides reference values that detail the percentage of size and the classification of the previous source in the function of age. There is wide variability of the average size of the previous source, which implies premature closure or possible delay as variants of normality.

Photosynthesis limitations in cacao leaves under different agroforestry systems in the Colombian Amazon.

Cacao (Theobroma cacao L.) has traditionally been considered a crop that requires shade, and consequently it is implemented under agroforestry systems (AFs) in order to regulate the level of incident solar radiation. However, optimal shade levels for this tree crop may vary depending on the climate conditions of where it is grown. Here we analyzed the physiological performance of cacao under three different AFs in the Colombian Amazon that differed in solar radiation patterns: high (HPAR), medium (MPAR), or low (LPAR) mean daily incident radiation. The physiological performance was characterized using photosynthetic variables in leaves such as light- and CO2-response curves, chlorophyll a fluorescence parameters, and total chlorophyll and carotenoid contents, in conjunction with other leaf functional traits. Cacao trees exposed to HPAR showed an improved physiological performance as compared to those from the other two AFs. Compared to MPAR and LPAR, cacao trees in HPAR doubled the rate of net carbon assimilation and reached higher maximum rates of RuBisCO carboxylation and RuBP regeneration. Moreover, cacao trees in HPAR presented photoprotection mechanisms that avoided photoinhibition, which was accompanied by a greater non-photochemical quenching coefficient and biochemical and morphological adjustments (low chlorophyll but higher carotenoid contents and low specific leaf area) compared to cacao trees from the other AFs. Overall, our results show that, due to the high cloud cover in the Colombian Amazon, cacao plantations under conditions of sparse shade maximized their carbon use, showing an improved physiological performance as a result of higher photosynthetic rates and energy dissipation mechanisms. If the crop were managed with sparse shade, the paradigm that favors the cultivation of cacao under shade would be called into question in the Colombian Amazon and other regions with similar climatic conditions.

First typology of cacao (Theobroma cacao L.) systems in Colombian Amazonia, based on tree species richness, canopy structure and light availability.

AIM AND BACKGROUND: We present a typology of cacao agroforest systems in Colombian Amazonia. These systems had yet to be described in the literature, especially their potential in terms of biodiversity conservation. The systems studied are located in a post-conflict area, and a deforestation front in Colombian Amazonia. Cacao cropping systems are of key importance in Colombia: cacao plays a prime role in post conflict resolution, as cacao is a legal crop to replace illegal crops; cacao agroforests are expected to be a sustainable practice, promoting forest-friendly land use. MATERIAL AND METHODS: We worked in 50 x 2000 m2 agroforest plots, in Colombian Amazonia. A cluster analysis was used to build a typology based on 28 variables characterised in each plot, and related to diversity, composition, spatial structure and light availability for the cacao trees. We included variables related to light availability to evaluate the amount of transmitted radiation to the cacao trees in each type, and its suitability for cacao ecophysiological development. MAIN RESULTS: We identified 4 types of cacao agroforests based on differences concerning tree species diversity and the impact of canopy spatial structure on light availability for the cacao trees in the understorey. We found 127 tree species in the dataset, with some exclusive species in each type. We also found that 3 out of the 4 types identified displayed an erosion of tree species diversity. This reduction in shade tree species may have been linked to the desire to reduce shade, but we also found that all the types described were compatible with good ecophysiological development of the cacao trees. MAIN CONCLUSIONS AND PROSPECTS: Cacao agroforest systems may actually be achieving biodiversity conservation goals in Colombian Amazonia. One challenging prospect will be to monitor and encourage the conservation of tree species diversity in cacao agroforest systems during the development of these cropping systems, as a form of forest-friendly management enhancing sustainable peace building in Colombia.

Importancia cultural de vegetación arbórea en sistemas ganaderos del municipio de san vicente del caguán, colombia / Cultural significance of arboreous vegetation in livestock systems of the municipality of san vicente del caguan, colombia

El conocimiento local juega un papel importante en la identificación de especies arbóreas, que contribuyen a la formación de alternativas para sistemas ganaderos, en función a la conservación, la protección del ambiente y la economía de los productores. En la actualidad, se hace necesario conocer alternativas y beneficios para afrontar la variabilidad del clima, que afecta la producción ganadera. Es por ello, que el conocimiento de los productores ganaderos incide sobre la percepción y la toma de decisiones. En este sentido, el objetivo de este estudio fue determinar la importancia cultural de especies arbóreas en los sistemas ganaderos, por medio del conocimiento local. Se realizaron 57 encuestas, para el desarrollo de la metodología de índice de importancia cultural de las especies arbóreas. Se encontró, que las especies para sombra, son las de mayor preferencia; el segundo uso más frecuente es la implementación de árboles para la mitigación y la adaptación al cambio climático y, por último, especies de usos agrícolas. Además, se reconoció que las especies con mayor índice de importancia cultural (IIC) e intensidad de uso (IU) fue Zygia longifolia, con 3,21 IIC y 60% IU, respectivamente. Asimismo, se reconoció que el uso de especies para sombra son las de mayor predominancia, con 132 menciones y una diferencia significativa de 24 menciones, para cercas vivas. Este estudio permitió reconocer el conocimiento de los productores sobre el valor y el uso de las especies arbóreas y forrajeras, para determinar las especies con mayor importancia cultural.

Local knowledge plays an important role in the identification of tree species that contribute to the formation of alternatives to livestock systems in terms of conservation, protection of the environment and producers' economies. At present, it is necessary to know alternatives and benefits to face the variability of the climate that affects livestock production. This is why the knowledge of livestock producers affects the perception and decision making. In this sense, the objective was to determine the cultural importance of tree species in livestock systems through local knowledge. 57 surveys were carried out for the development of the methodology of index of cultural importance of the tree species. It was found that the species for shade are the most preferred; the second most frequent use is the implementation of trees for the mitigation and adaptation to the climatic change and last species of agricultural uses. In addition, it was recognized that the species with the highest cultural importance index (CIU) and intensity of use (UI) were Zygia longifolia with 3.21 IIC and 60% IU, respectively. Also, it was recognized that the use of species for shade are the most predominant with 132 mentions and a significant difference of 24 mentions for live fences. This study allowed to recognize the knowledge of the producers on the value and use of the tree species and fodder species to determine the species with greater cultural importance.

Health care utilization of mexican patients with medically unexplained physical symptoms.

OBJECTIVE: To determine the prevalence of medically unexplained physical symptoms and the characteristics and use of health services in a group of patients with medically unexplained physical symptoms and a group of patients with other illnesses. METHODS: This was a cross-sectional, retrospective and multicenter study. We included 1,043 patients over 18 years of age from 30 primary care units of a government health institution, in 11 states of Mexico, attended by 39 family physicians. The prevalence of medically unexplained physical symptoms was determined and both groups with or without symptoms were compared with regard to drug use, laboratory and other studies, leaves of absence, and referrals in the last six months. The group with medically unexplained physical symptoms was diagnosed using the Patient Health Questionnaire and the diagnostic criteria of Reid et al. Emergency or terminal illnesses were excluded. The chi square test was used with a statistical significance of p < 0.05. RESULTS: Medically unexplained physical symptoms was diagnosed in 73 patients (7.0%). The majority were women (91.8%); their predominant symptom was from the gastrointestinal system in 56 (76.7%). This group had a greater use of clinical studies and referrals to other services (mean 1.1 vs. 0.5; p <0.0001 and 0.6 vs. 0.8; p < 0.01, respectively). CONCLUSIONS: The prevalence of medically unexplained physical symptoms was low, but with a greater impact on some health services. This could represent an overload in medical costs. OBJETIVO: Determinar la prevalencia de Síntomas Físicos Medicamente No Explicables y las características y uso de los servicios de salud entre el grupo de pacientes con Síntomas Físicos Medicamente No Explicables, y el grupo con otras enfermedades. MÉTODOS: Estudio transversal, retroprospectivo y multicéntrico. Se incluyeron a 1,043 pacientes mayores de 18 años, en 30 unidades de atención primaria de una institución gubernamental en salud, en 11 estados de la República Mexicana, atendidos por 39 médicos familiares. Se estimó la prevalencia de Síntomas Físicos Medicamente No Explicables y se compararon los dos grupos con y sin estos síntomas, en cuanto al uso de medicamentos, estudios de laboratorio, de gabinete, incapacidades y referencias en los últimos seis meses. El grupo de Síntomas Físicos Medicamente No Explicables fue diagnosticado por el Patient Health Questionnaire (son los síntomas físicos más comúnmente referidos por estos pacientes en el primer nivel de atención), además de criterios diagnósticos de Reid et al. Se excluyeron urgencias o con enfermedad terminal. Se utilizó prueba Chi cuadrada con p <0.05 para significancia estadística. RESULTADOS: El 7.0% (73) se diagnosticó como Síntomas Físicos Medicamente No Explicables, la mayoría mujeres (91.8%); el síntoma predominante pertenece al sistema gastrointestinal con 76.7% (56). Este grupo demandó mayor uso de estudios de gabinete y referencias a otros servicios (media 1.1 vs. 0.5; p <0.0001 y 0.8 vs 0.6; p <0.01, respectivamente). CONCLUSIONES: La prevalencia de Síntomas Físicos Medicamente No Explicables fue baja, pero con impacto significativo en el uso de algunos servicios de salud. Esto pudiera representar un mayor costo comparado con otro grupo de pacientes.

Health care utilization of mexican patients with medically unexplained physical symptoms / Uso de los servicios de salud de pacientes mexicanos con síntomas físicos medicamente inexplicables

Abstract Objective: To determine the prevalence of medically unexplained physical symptoms and the characteristics and use of health services in a group of patients with medically unexplained physical symptoms and a group of patients with other illnesses. Methods: This was a cross-sectional, retrospective and multicenter study. We included 1,043 patients over 18 years of age from 30 primary care units of a government health institution, in 11 states of Mexico, attended by 39 family physicians. The prevalence of medically unexplained physical symptoms was determined and both groups with or without symptoms were compared with regard to drug use, laboratory and other studies, leaves of absence, and referrals in the last six months. The group with medically unexplained physical symptoms was diagnosed using the Patient Health Questionnaire and the diagnostic criteria of Reid et al. Emergency or terminal illnesses were excluded. The chi square test was used with a statistical significance of p < 0.05. Results: Medically unexplained physical symptoms was diagnosed in 73 patients (7.0%). The majority were women (91.8%); their predominant symptom was from the gastrointestinal system in 56 (76.7%). This group had a greater use of clinical studies and referrals to other services (mean 1.1 vs. 0.5; p <0.0001 and 0.6 vs. 0.8; p < 0.01, respectively). Conclusions: The prevalence of medically unexplained physical symptoms was low, but with a greater impact on some health services. This could represent an overload in medical costs....au

Resumen Objetivo: Determinar la prevalencia de Síntomas Físicos Medicamente No Explicables y las características y uso de los servicios de salud entre el grupo de pacientes con Síntomas Físicos Medicamente No Explicables, y el grupo con otras enfermedades. Métodos: Estudio transversal, retroprospectivo y multicéntrico. Se incluyeron a 1,043 pacientes mayores de 18 años, en 30 unidades de atención primaria de una institución gubernamental en salud, en 11 estados de la República Mexicana, atendidos por 39 médicos familiares. Se estimó la prevalencia de Síntomas Físicos Medicamente No Explicables y se compararon los dos grupos con y sin estos síntomas, en cuanto al uso de medicamentos, estudios de laboratorio, de gabinete, incapacidades y referencias en los últimos seis meses. El grupo de Síntomas Físicos Medicamente No Explicables fue diagnosticado por el Patient Health Questionnaire (son los síntomas físicos más comúnmente referidos por estos pacientes en el primer nivel de atención), además de criterios diagnósticos de Reid et al. Se excluyeron urgencias o con enfermedad terminal. Se utilizó prueba Chi cuadrada con p <0.05 para significancia estadística. Resultados: El 7.0% (73) se diagnosticó como Síntomas Físicos Medicamente No Explicables, la mayoría mujeres (91.8%); el síntoma predominante pertenece al sistema gastrointestinal con 76.7% (56). Este grupo demandó mayor uso de estudios de gabinete y referencias a otros servicios (media 1.1 vs. 0.5; p <0.0001 y 0.8 vs 0.6; p <0.01, respectivamente). Conclusiones: La prevalencia de Síntomas Físicos Medicamente No Explicables fue baja, pero con impacto significativo en el uso de algunos servicios de salud. Esto pudiera representar un mayor costo comparado con otro grupo de pacientes...au

Vaccines for viral and bacterial pathogens causing acute gastroenteritis: Part I: Overview, vaccines for enteric viruses and Vibrio cholerae.

Efforts to develop vaccines for prevention of acute diarrhea have been going on for more than 40 y with partial success. The myriad of pathogens, more than 20, that have been identified as a cause of acute diarrhea throughout the years pose a significant challenge for selecting and further developing the most relevant vaccine candidates. Based on pathogen distribution as identified in epidemiological studies performed mostly in low-resource countries, rotavirus, Cryptosporidium, Shigella, diarrheogenic E. coli and V. cholerae are predominant, and thus the main targets for vaccine development and implementation. Vaccination against norovirus is most relevant in middle/high-income countries and possibly in resource-deprived countries, pending a more precise characterization of disease impact. Only a few licensed vaccines are currently available, of which rotavirus vaccines have been the most outstanding in demonstrating a significant impact in a short time period. This is a comprehensive review, divided into 2 articles, of nearly 50 vaccine candidates against the most relevant viral and bacterial pathogens that cause acute gastroenteritis. In order to facilitate reading, sections for each pathogen are organized as follows: i) a discussion of the main epidemiological and pathogenic features; and ii) a discussion of vaccines based on their stage of development, moving from current licensed vaccines to vaccines in advanced stage of development (in phase IIb or III trials) to vaccines in early stages of clinical development (in phase I/II) or preclinical development in animal models. In this first article we discuss rotavirus, norovirus and Vibrio cholerae. In the following article we will discuss Shigella, Salmonella (non-typhoidal), diarrheogenic E. coli (enterotoxigenic and enterohemorragic), and Campylobacter jejuni.