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We evaluated the main leaching indices that have been used for decades for the protection of groundwater against contamination by pesticides. We describe the index classifications in detail and discuss their advantages and limitations relative to their prediction value. Most of the indices have similarities in the types of parameters they use. Some of the similarities are basic physicochemical properties of the pesticides such as their water solubility and their organic carbon partition coefficient, as well as characteristics such as environmental persistence in the soil and some soil characteristics. It is very difficult to maintain a simple index with high predictive power. However, comparisons are allowed by many indices among different active ingredients before pesticides are classified according to the risk of being groundwater contaminants. In contrast, limitations are the scarce inclusion of pesticide byproducts in the ground, lack of prediction capacity for polar pesticides, and lack of prediction of the vulnerability of groundwater to being contaminated by pesticides. Despite the limitations of such approaches, they are of great utility, particularly for protection of groundwater from pesticide contamination when little information is available, which is the case in most developing countries and in countries with economies in transition. Caution is recommended in the analysis of information generated by these approximations, which ideally should be validated experimentally in the different application scenarios and the needs for pesticide assessment based on local information. Environ Toxicol Chem 2024;00:1-14. © 2024 SETAC.
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Antarctica is the most remote and coldest regions of the planet, but the presence of REEs there has received little attention. This study assessed REE-contents in the feathers of adult gentoo penguins from Ardley Island, Kopaitic Island and Base O'Higgins. Field work was accomplished during 2011 (austral summer), and determination of elements was performed with ICP-MS. In general, REE-levels showed descending relations as follows: Ce > La > Y > Nd > Sc > Pr > Gd > Sm > Dy >Er > Yb > Eu > Ho > Tb > Tm > Lu. The data showed an increase of the levels of REEs from the lower part of the feather to the tip. This finding seems to be spatially dependent, but geochemical, anthropogenic conditions, feeding habits, sex, or even health status of birds should also be considered. It is a subject that requires deeper attention in future studies.
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Metales de Tierras Raras , Spheniscidae , Animales , Regiones Antárticas , PlumasRESUMEN
Rare earth elements (REEs) are a group of chemicals widely used in emerging technologies today, and are often labeled as potential environmental contaminants. The Cayos Cochinos Archipelago is a protected area of Honduras, Central America, with intertidal and supratidal sands, making it a prime candidate for pollution research. In December 2022, sand samples from the Cayos Cochinos area was collected and analyzed by X-ray fluorescence to determine the levels of REEs and some less-studied trace elements (TEs). Based on the findings, REEs mean contents (µg g-1 d.w.) fluctuated between 2.96 for Y to 667.1 for Nd, while TEs ranged from 10.37 for Th to 3896.2 for Sr. Also, the results showed significantly higher levels of La, Pr, Y, Sr, Ba, and Th in the supratidal zone than in the intertidal zone. The data are useful as a basis for understanding the presence of chemical elements in near-shore marine areas and subsequently help identify sustainable practices that will reduce the impacts of these chemicals.
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Metales de Tierras Raras , Oligoelementos , Arena , Oligoelementos/análisis , Metales de Tierras Raras/análisis , Contaminación Ambiental/análisis , Región del CaribeRESUMEN
Complex thinking is a cognitive skill that focuses on the integrated analysis and synthesis of information with a systemic and critical perspective that enables creative decision-making in the face of complex realities or challenges. At the educational level, it is valued as a transdisciplinary competency, meaning it is relevant for individuals regardless of their profession or field of study. This article presents the results of measuring the perceived achievement of complex thinking among 830 graduating students from a technological university in Mexico, aiming to identify possible significant differences based on their discipline or major. Methodologically, a multivariate descriptive statistical analysis was performed using R and RStudio software, including calculation of means and standard deviations, violin plots, boxplot and ANOVA significance analysis, and t-test. The results show that the differences were not statistically significant in all the disciplines, although it is possible to note significant differences, which reveals a differentiated behavior in the process of formation and development of complex thinking according to the discipline of study. In conclusion, the present study shows that the students' areas of training are associated with differences in perception of complex thinking and its associated sub-competencies, thus differentiating this ability in their graduation profile. This article contributes to the existing literature on the formation and development of complex thinking and its sub-competencies as relevant professional skills for lifelong learning.
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Patagonia is one of the last pristine regions on the southern hemisphere. The impact of rare earth element (REEs) and trace elements (TEs) in this region have received little attention. The main goal was to assess REEs burden in feathers of adult magellanic penguins (Spheniscus magellanicus). Sampling was performed at Magdalena Island of the Chilean Patagonia during the austral summer of 2011. Multi-elemental determination of 16 REEs and 24 TEs was performed with ICP-MS. The levels of REEs, TEs, and stable isotopes (δ15N, δ13C, and δ34S) were measured to assess the factors that condition the avian exposure to environmental contaminants. The results showed an increase of the levels of REEs and TEs from the calamus to the feather's tip. In the whole feather, the highest levels corresponded to Ce, which exhibited more than two order of magnitude than Lu and Tm levels. Similar to other penguin species, magellanic penguins can be vectors of REEs and metals in remote regions. Stable isotopes revealed that trophic ecology may influence some of the element concentrations in feathers of magellanic penguins, an issue that requires deeper attention.
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Metales de Tierras Raras , Spheniscidae , Oligoelementos , Animales , Oligoelementos/análisis , Plumas/química , ChileRESUMEN
Resumen Existe un gran número de enfermedades del tejido mamario que tienen patrones radiológicos específicos y hallazgos imagenológicos concretos. No obstante, el linfoma anaplásico de células gigantes asociado a implantes mamarios (LACG-AIM) es una enfermedad con hallazgos poco específicos que ha presentado un aumento en su incidencia debido al crecimiento exponencial de la mamoplastia de aumento a lo largo de los años en todo el mundo, así como al uso de implantes tanto en cirugía estética como reconstructiva. En este artículo se realiza una revisión de la epidemiología, etiología, fisiopatología y diagnóstico del LACG-AIM. Se plantean hallazgos radiológicos sugestivos de esta enfermedad, lo que permite al radiólogo aportar información al equipo tratante para el diagnóstico y la planificación quirúrgica en caso de ser necesario.
Abstract There are many diseases related to breast tissue that have specific radiological patterns and imaging findings. However, anaplastic large cell lymphoma associated with breast implants is a condition with nonspecific findings that has an increased incidence due to the exponential growth worldwide of augmentation mammoplasty over the years and the use of implants in aesthetic and reconstructive surgery. In this article, a review of the epidemiology, etiology, pathophysiology, and diagnosis of this disease is carried out, highlighting radiological findings suggestive of this disease, which allows the radiologist to provide information to the treating team for diagnosis and surgical planning if necessary.
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Resumen Introducción: el síndrome de Morel-Lavallée (SML) es una lesión por desgarro en la fascia profunda y el tejido celular subcutáneo causada por cizallamiento. La incidencia del SML ha sido estimada en alrededor de 0.7% en pacientes víctimas de accidente de tránsito. El diagnóstico se realiza mediante la exploración clínica, ecografía y resonancia magnética. El síndrome se ha clasificado en seis tipos imagenológicos de acuerdo a la cronicidad, composición del tejido y aspecto en la resonancia magnética. Estas lesiones tienen una tasa de infección de 46%, que pueden poner en riesgo la vida del paciente, por lo cual requieren manejo oportuno. Métodos: paciente masculino de 20 años quien sufre accidente de tránsito en calidad de ciclista, en donde fue arrastrado por un vehículo de carga generando quemaduras por fricción de primer, segundo y tercer grado en hemicuerpo izquierdo asociado a formación de hematomas en las extremidades inferiores que condicionaron la aparición del SML, a través de la aplicación de escleroterapia, bursectomía y la técnica novedosa de las incisiones en "emparrillado" se logró la resolución de los seromas crónicos. Resultados: después de un juicioso estudio de la historia clínica, las imágenes diagnósticas y el examen físico se logra documentar que se estaba frente al caso de un síndrome de Morel Lavallée el cual es muy raro en la población por lo que hace difícil su diagnóstico, sin embargo, después de un largo tiempo, múltiples intervenciones por el equipo quirúrgico y la instauración de técnicas hibridas en el manejo de esta patología se logró un muy buen resultado tanto funcional como estético. Conclusiones: en este caso se presenta una técnica novedosa en el tratamiento del SML en un centro de salud privado, con aparición inusual en las heridas postraumáticas, que a pesar del manejo temprano pueden progresar a su etapa tardía y generar complicaciones serias. Es importante realizar un diagnóstico temprano y un manejo adecuado para evitar complicaciones graves en pacientes con SML.
Abstract Introduction: Morel-Lavallée syndrome (MLS) is a tearing injury to the deep fascia and subcutaneous cellular tissue caused by shearing. The incidence of MLS has been estimated to be about 0.7% in patients who are victims of traffic accidents. The diagnosis is made by clinical examination, ultrasonography and magnetic resonance imaging. The syndrome has been classified into six imaging types according to chronicity, tissue composition and MRI appearance. These lesions have an infection rate of 46%, which can be life-threatening and therefore require timely management. Methods: 20-year-old male patient who suffers traffic accident as a cyclist, where he was dragged by a cargo vehicle generating friction burns of first, second and third degree in left hemibody associated with hematoma formation in the lower extremities that conditioned the appearance of SML, through the application of sclerotherapy, bursectomy and the novel technique of incisions in "grid" the resolution of chronic seromas was achieved. Results: after a judicious study of the clinical history, diagnostic images and physical examination it was possible to document that it was a case of a Morel Lavallée syndrome which is very rare in the population making its diagnosis difficult, however after a long time, multiple interventions by the surgical team and the establishment of hybrid techniques in the management of this pathology a very good result both functional and aesthetic was achieved. Conclusions: this case presents a novel technique in the treatment of SML in a private health center, with unusual occurrence in post-traumatic wounds, which despite early management can progress to its late stage and generate serious complications. Early diagnosis and proper management are important to avoid serious complications in patients with SML.
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This article describes a study that sought to identify the correlation between social entrepreneurship and complex thinking competencies in a population of Mexican students. The article uses the novel approach of compositional data analysis. Compositional data analysis focuses on studying data that are part of a whole, whose importance lies in the relative information between its parts and not in absolute values. The analysis allows us to identify an association between the competencies and find statistically significant relationships between sub-competencies. In particular, correlations can be seen between the sub-competencies of scientific thinking and critical thinking with the sub-competency of self-control, leadership, and social awareness and social value. Furthermore, a correlation is observed between systemic thinking with the sub-competency of social awareness and social value, self-control, and leadership sub-competencies. In a practical way, this article introduces the compositional data analysis methodology to the academic educational literature focused on the study and measurement of competencies, opening possibilities for more precise, broad, descriptive analyses not achieved with other methodologies.
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Resumen El libro titulado "Manejo inicial del paciente quemado, segunda edición" escrito por el médico Andrés Ferro Morales, quien es especialista en cirugía plástica-estética y reconstructiva de la Universidad Nacional de Colombia, actualmente profesor titular y coordinador académico del posgrado de cirugía plástica en la Universidad el Bosque y profesor asociado del programa de cirugía plástica de la Universidad Nacional de Colombia, es el objeto de esta reseña. Se podría decir que este libro ha sido uno de los textos guías primordiales en la formación de varias de las generaciones de residentes de cirugía plástica, internos y estudiantes de medicina en el país por su considerable riqueza bibliográfica y su sobresaliente forma de expresar los distintos temas que se tratan en el manejo del paciente quemado lo que lo hace un texto grandioso para cualquier persona del sector salud interesada en el aprendizaje de este tema.
Abstract The book titled "Initial Management of the Burned Patient, second edition" written by Dr. Andres Ferro Morales who is a specialist in aesthetic and reconstructive plastic surgery from the Universidad Nacional de Colombia, a professor and academic coordinator of the postgraduate program in plastic surgery at the Universidad El Bosque and associate professor of the plastic surgery program at the Universidad Nacional de Colombia, is the subject of this review. It could be said that this book has been one of the main guiding texts in the training of several generations of plastic surgery residents, interns, and medical students in the country due to its considerable bibliographic wealth and its outstanding way of expressing the different topics that are discussed in the management of burn patients, which makes it a great text for anyone in the health sector interested in learning about this topic.
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BACKGROUND: Simultaneous co-fermentation of mixed sugars is an important feature to consider in the production of ethanol from lignocellulosic biomass hydrolysates because it enhances the overall ethanol yield and volumetric productivity during fermentation. Continuous cultures can be used during ethanol production from lignocellulosic hydrolysates to prevent catabolite repression by glucose on other sugars, such as xylose, and thus promote the simultaneous and total consumption of sugars and reduce fermentation time. The use of single- and two-stage continuous cultures under micro-aerated conditions for simultaneous consumption of xylose and glucose, and fermentation to ethanol by ethanologenic Escherichia coli strain MS04 was studied. Mineral medium supplemented with glucose, xylose and sodium acetate, was used to compare continuous cultures performance to batch cultures. RESULTS: Single-stage continuous cultures under micro-aerated conditions allowed the total co-consumption of a mixture of glucose and xylose (7.5 and 42.5 g/L, respectively) in mineral medium, with steady state ethanol production of 18 g/L, and a volumetric ethanol productivity of 0.9 g/L h, when low dilution rates (0.05 h-1) were used. However, the volumetric productivity was lower than the batch process under similar conditions (1.3 g/L h). Conversely, micro-aerated two-stage continuous culture enhanced the volumetric productivity up to 1.6 g/L h at a dilution rate of 0.15 h-1, with a total consumption of sugars and a slight reduction of the overall ethanol yield. CONCLUSIONS: The total and simultaneous consumption of glucose and xylose by the ethanologenic E. coli strain MS04 was accomplished by using two-stage continuous culture under micro-aerated conditions with an increase in the volumetric ethanol productivity of 23% and 78% when compared to batch and single-stage continuous cultures, respectively. Multi-stage continuous cultivation can be used to promote the simultaneous consumption of all sugars contained in biomass hydrolysates, and thus increase the volumetric ethanol productivity of the fermentation process.
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Técnicas de Cultivo Celular por Lotes , Disacáridos/metabolismo , Escherichia coli/metabolismo , Etanol/metabolismo , FermentaciónRESUMEN
BACKGROUND: The Plasmodium vivax multidrug resistant 1 gene (pvmdr1) codes for a transmembrane protein of the parasite's digestive vacuole. It is likely that the pvmdr1 gene mutations occur at different sites by convergent evolution. In here, the genetic variation of pvmdr1 at three sites of the Mesoamerican region was studied. Since 1950s, malarious patients of those areas have been treated only with chloroquine and primaquine. METHODS: Blood samples from patients infected with P. vivax were obtained in southern Mexico (SMX), in the Northwest (NIC-NW) and in the northeast (NIC-NE) of Nicaragua. Genomic DNA was obtained and fragments of pvmdr1 were amplified and sequenced. The nucleotide and amino acid changes as well as the haplotype frequency in pvmdr1 were determined per strain and per geographic site. The sequences of pvmdr1 obtained from the studied regions were compared with homologous sequences from the GenBank database to explore the P. vivax genetic structure. RESULTS: In 141 parasites, eight nucleotide changes (two changes were synonymous and other six were nonsynonymous) were detected in 1536 bp. The PvMDR1 amino acid changes Y976F, F1076FL were predominant in endemic parasites from NIC-NE and outbreak parasites in NIC-NW but absent in SMX. Thirteen haplotypes were resolved, and found to be closely related, but their frequency at each geographic site was different (P = 0.0001). The pvmdr1 codons 925-1083 gene fragment showed higher genetic and haplotype diversity in parasites from NIC-NE than the other areas outside Latin America. The haplotype networks suggested local diversification of pvmdr1 and no significant departure from neutrality. The F ST values were low to moderate regionally, but high between NIC-NE or NIC-NW and other regions inside and outside Latin America. CONCLUSIONS: The pvmdr1 gene might have diversified recently at regional level. In the absence of significant natural, genetic drift might have caused differential pvmdr1 haplotype frequencies at different geographic sites in Mesoamerica. A very recent expansion of divergent pvmdr1 haplotypes in NIC-NE/NIC-NW produced high differentiation between these and parasites from other sites including SMX. These data are useful to set a baseline for epidemiological surveillance.
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Proteínas Asociadas a Resistencia a Múltiples Medicamentos/genética , Plasmodium vivax/genética , Polimorfismo Genético , Proteínas Protozoarias/genética , Selección Genética , Haplotipos , México , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/metabolismo , Nicaragua , Proteínas Protozoarias/metabolismoRESUMEN
Resumen: Introducción: La prevalencia del síndrome eutiroideo enfermo en pacientes con sepsis es aproximadamente de 60%; existe poca información sobre su correlación con falla multiorgánica. Objetivo: Estimar la prevalencia del síndrome eutiroideo enfermo (SEE) y correlacionar con la presencia de fallas orgánicas específicas y puntajes de gravedad y desenlaces clínicos. Métodos: Se incluyeron pacientes con diagnóstico de sepsis en una unidad de cuidados críticos durante el periodo comprendido de marzo de 2014 a febrero de 2016; se tomaron variables clínicas y estudios de laboratorio que incluían perfil tiroideo en todos los pacientes. Análisis estadístico: Estadística descriptiva con medidas de frecuencia, tendencia central y dispersión. Se realizaron análisis de supervivencia con modelos de regresión de Cox y curvas de Kaplan-Meier para mortalidad; razones de riesgo e intervalos de confianza de 95%. Un error alfa ajustado menor de 5% a dos colas fue considerado significativo. Se usó la paquetería estadística STATA SE versión 11.1. Resultados: Se incluyó un total de 90 pacientes, 51.1% de sexo femenino, con edad de 71 ± 14.15 años, IMC al ingreso a la UCI de 24.94 ± 5.07 kg/m2. La prevalencia global de SEE es de 61.1%. Los pacientes con SEE presentaron en mayor proporción falla hemodinámica, renal y hematológica, sin alcanzar significancia estadística. En la fases combinadas 2 y 3 de SEE, sí se observó mayor proporción de falla renal: 88 versus 63.3%, RR = 1.8 (IC 95% 1.1-2.6, p = 0.037), así como altas dosis de vasopresores (norepinefrina > 0.1 µg/kg/min) RR = 2.3 (IC 95% 1.063-5.18, p = 0.024) y menor supervivencia, con una mediana en días de 28 (RIQ 19-39) versus 26 (RIQ 13-36), p = 0.7; PCT igual o mayor a 6 en un 65.5 versus 40%, RR = 1.87 (IC 95% 1.1-3.1, p = 0.18), mayor puntaje de SOFA con mediana de 12 (RIQ 8-4) versus 9 (RIQ 7-13) puntos, p = 0.09. Además, peores desenlaces durante la estancia hospitalaria, evaluados por un índice compuesto que incluye mortalidad, necesidad de ventilación mecánica invasiva (VMI), SOFA ≥ 9 con un RR = 1.713 (IC 95% 1.036-2.83, p = 0.05). El análisis de curva ROC detectó el mejor punto de corte de SOFA como predictor de SEE ≥ 11 con sensibilidad 60.0, especificidad 62 LR + 1.6, LR - 0.63, AUC = 0.6. RR = 1.7 (IC 95% 1.024-3.05, p = 0.034). Conclusiones: Los pacientes con SEE presentan mayor elevación de marcadores de inflamación, requerimiento de vasopresores y soporte ventilatorio, compromiso multiorgánico y mortalidad.
Abstract: Introduction: The prevalence of euthyroid sick syndrome in patients with sepsis is approximately 60%; there is little information on its correlation with multiorgan failure. Objective: To estimate the prevalence of euthyroid sick syndrome (ESS) and correlate it with the presence of specific organ failures, severity scores and clinical outcomes. Methods: Patients with diagnosis of sepsis in a critical care unit during the period from March 2014 to February 2016; we registered the clinical variables and laboratory studies, including thyroid function, in all patients. Statistical analysis: Descriptive statistics with frequency measures of central tendency and dispersion. Mortality-survival analysis with Cox regression models and Kaplan-Meier were made, as well as risk ratios and confidence intervals of 95%. A two-tailed adjusted alpha error of less than 5% was considered significant. The statistical package STATA SE version 11.1 was used. Results: Ninety patients were included, 51.1% female, aged 71 ± 14.15 years; the BMI at admission to the ICU was 24.94 ± 5.07 kg/m2. The overall prevalence of ESS was 61.1%. ESS patients presented in greater proportion with hemodynamic, renal and hematologic failure, without reaching statistical significance. In the combined phases 2 and 3 of SEE, a higher proportion of renal failure was observed: 88 vs. 63.3 %, RR = 1.8 (95% CI 1.1-2.6, p = 0.037). High doses of vasopressors (norepinephrine > 0.1 µg/kg/min) RR = 2.3 (95% CI 1.063-5.18, p = 0.024). Lower survival with a median of 28 days (IQR 19-39) versus 26 (IQR 13-36), p = 0.7. PCT greater than or equal to 6 in 65.5 versus 40%, RR = 1.87 (95% CI 1.1-3.1, p = 0.18); higher SOFA score with a median of 12 (IQR 8-4) versus 9 (IQR 7-13) points, p = 0.09. In addition to worse outcomes during hospital stay evaluated by a composite index that included mortality, need for invasive mechanical ventilation (IMV), SOFA ≥ 9 with a RR = 1.713 (95% CI 1.036-2.83, p = 0.05). ROC curve analysis detected the best cut of SOFA as a predictor of ESS ≥11, sensitivity 60.0, specificity 62 LR + 1.6, LR-0.63, AUC = 0.6. RR = 1.7 (95% CI 1.024-3.05, p = 0.034). Conclusions: Patients with ESS have higher markers of inflammation, increased requirement for vasopressors and ventilatory support, as well as elevated multiorgan failure and mortality.
Resumo: Introdução: A prevalência da síndrome do doente eutireoidiano em pacientes com sepse é de aproximadamente 60%, além disso há pouca informação sobre sua correlação com a insuficiência de múltiplos órgãos. Objetivo: Estimar a prevalência da síndrome do doente eutireoidiano (ESS) e correlacionar com a presença de insuficiência orgânica específica, pontuações de gravidade e desenlaces clínicos. Foram incluídos pacientes diagnosticados com sepse em uma unidade de terapia intensiva durante o período de março de 2014 a fevereiro de 2016, se tomaram variáveis clínicas e estudos laboratoriais que incluiam perfil tireoidiano em todos os pacientes. Análise estatística: Estatística descritiva com medidas de frequência, tendência central e dispersão. Realizaram-se análises de sobrevivência com modelos de regressão de Cox e curvas de Kaplan-Meier para mortalidade. Taxas de risco e intervalos de confiança de 95%. O erro alfa ajustado menor a 5% bicaudal, serão considerados significativos. O programa estatístico STATA versão 11.1. Resultados: Incluiram-se um total de 90 pacientes, 51.1% do sexo feminino, com idades entre 71 ± 14.15 anos, IMC na admissão na UTI foi de 24.94 ± 5.07 kg/m2. A prevalência global de ESS foi de 61.1%. Os pacientes com ESS apresentaram maior proporção de alteração hemodinâmica, renal e hematológica sem alcançar significância estatística. Nas fases 2 e 3 combinadas de ESS se observou maior proporção de insuficiência renal 88 versus 63.3%, RR = 1.8 (IC 95%1.1-2.6, p = 0.037). Altas doses de vasopressores (norepinefrina > 0.1 µg/kg/min) RR = 2.3 (IC 95% 1.063-5.18, p = 0.024). Menor sobrevida com uma média em dias de 28 (IQR 19-39) vs 26 (RIQ 13-36), p = 0.7. PCT igual ou maior a 6 em um 65.5 vs 40%, RR = 1.87 (IC de 95% 1.1-3.1, p = 0.18) maior pontuação SOFA com uma média de 12 (RIQ 8-4) vs 9 (RIQ 7-13) pontos, p = 0.09. Ademais com piores desenlaces durante a estadia hospitalar avaliada por um índice de composto que inclui a mortalidade, a necessidade de VMI, SOFA ≥ 9 com um RR = 1.713 (IC 95% 1.036-2.83, p = 0.05). A análise da curva ROC detectou o melhor ponto de corte de SOFA como um preditor de ESS ≥ 11 sensibilidade 60.0, especificidade 62 LR + 1.6, LR-0.63, AUC = 0.6. RR = 1.7 (IC de 95% 1.024-3.05, p = 0.034). Conclusões: Os pacientes com ESS apresentam maior elevação dos marcadores inflamatórios, maior necessidade de vasopressores, suporte ventilatório, compromisso múltiplo de órgãos e mortalidade.
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BACKGROUND: Mexico advanced to the pre-elimination phase in 2009 due to a significant reduction in malaria cases, and since 2000, Plasmodium vivax is the only species transmitted. During the last two decades, malaria transmission has been mostly local and isolated to a few regions. It is important to gain further insights into the impact of control measures on the parasite population structure. Hence, the aim of the current study was to determine detailed changes in P. vivax genetic diversity and population structure based on analysing the gene that encodes the apical membrane antigen 1 (pvama1). This analysis covered from control to pre-elimination (1993-2011) in a hypo-endemic region in southern Mexico. RESULTS: The 213 pvama1 I-II sequences presently analysed were grouped into six periods of three years each. They showed low genetic diversity, with 15 haplotypes resolved. Among the DNA sequences, there was a gradual decrease in genetic diversity, the number of mixed genotype infections and the intensity of positive selection, in agreement with the parallel decline in malaria cases. At the same time, linkage disequilibrium (R2) increased. The three-dimensional haplotype network revealed that pvama1 I-II haplotypes were separated by 1-11 mutational steps, and between one another by 0-3 unsampled haplotypes. In the temporal network, seven haplotypes were detected in at least two of the six-time layers, and only four distinct haplotypes were evidenced in the pre-elimination phase. Structure analysis indicated that three subpopulations fluctuated over time. Only 8.5% of the samples had mixed ancestry. In the pre-elimination phase, subpopulation P1 was drastically reduced, and the admixture was absent. CONCLUSIONS: The results suggest that P. vivax in southern Mexico evolved based on local adaptation into three "pseudoclonal" subpopulations that diversified at the regional level and persisted over time, although with varying frequency. Control measures and climate events influenced the number of malaria cases and the genetic structure. The sharp decrease in parasite diversity and other related genetic parameters during the pre-elimination phase suggests that malaria elimination is possible in the near future. These results are useful for epidemiological surveillance.
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Antígenos de Protozoos/genética , Variación Genética , Malaria Vivax/transmisión , Proteínas de la Membrana/genética , Plasmodium vivax/genética , Proteínas Protozoarias/genética , Alelos , ADN Protozoario/genética , Evolución Molecular , Genotipo , Haplotipos , Humanos , Desequilibrio de Ligamiento , Malaria Vivax/parasitología , México , Análisis de Secuencia de ADN , Factores de TiempoRESUMEN
Malaria is still a grave public health problem in tropical areas of the world. The greater genetic diversity of Plasmodium vivax at geographic sites with less control over infection evidences the importance of genetic studies of these parasites. The present genetic study compares P. vivax in Nicaragua, which is still in the control phase, with this species in several other countries. In Nicaragua, P. vivax causes over 80% of malaria cases, most occurring in two remote northern regions. Plasmodium asexual blood-stage antigens, implicated in reticulocyte invasion, are possible molecular markers for analyzing parasite population genetics and for developing vaccines. The aim of this work was to investigate the genetic structure of P. vivax based on the 42kDa merozoite surface protein-1 (PvMSP-142), which may represent a sensitive marker for evaluating malaria transmission control. From blood samples of patients with P. vivax, we amplified PvMSP-142, obtained the nucleotide sequences, and compared them to homologous sequences of parasites from other geographic sites, retrieved from the GenBank. The 92 nucleotide sequences of P. vivax resulted in the resolution of eight haplotypes, six exclusive to Nicaragua. The great nucleotide diversity (π=0.020), the minimal recombination events (Rm=11), and the dN-dS values were similar to other control phase countries. FST values between parasites were low (0.069) for Nicaragua versus Brazil but higher for Nicaragua versus other regions (0.134-0.482). The haplotype network revealed five lineages: two were very frequent in Nicaragua and closely related to American parasites; three have been detected in multiple geographic sites around the world. These results suggest that P. vivax in Nicaragua is a differentiated and genetically diverse population (mainly due to mutation, positive balancing selection and recombination) and that PvMSP-142 may be a sensitive marker for evaluating sustained reduction in malaria transmission and for developing vaccines.
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Malaria Vivax/epidemiología , Malaria Vivax/parasitología , Proteína 1 de Superficie de Merozoito/genética , Plasmodium vivax/clasificación , Plasmodium vivax/genética , Dominios Proteicos/genética , Evolución Molecular , Variación Genética , Genética de Población , Haplotipos , Humanos , Malaria Vivax/diagnóstico , Proteína 1 de Superficie de Merozoito/química , Nicaragua/epidemiología , Filogenia , Filogeografía , Reacción en Cadena de la Polimerasa , Recombinación Genética , Selección Genética , Análisis de Secuencia de ADNRESUMEN
BACKGROUND: In Mexico, combined chloroquine (CQ) and primaquine (PQ) treatment has been used since the late 1950s to treat Plasmodium vivax infections. Although malaria transmission has declined, current treatment strategies must be evaluated to advance towards malaria elimination. METHODS: The clinical and parasitological outcome of treating symptomatic P. vivax with the 14-day (T14) treatment or intermittent single dose (ISD) regimen was evaluated in southern Mexico between February 2008 and September 2010. Patients over 12 months old with P. vivax mono-infection and asexual parasitaemia ≥500 parasites/µl were treated under supervision. After diagnosis (day 0), treatment began immediately. T14 patients received CQ for 3 days (10, 10 and 5 mg/kg) and PQ daily for 14 days (0.25 mg/kg), while ISD patients received a single dose of CQ (10 mg/kg) and PQ (0.75 mg/kg) on days 0, 30, 60, 180, 210, and 240. Follow-up was done by observing clinical and laboratory (by microscopy, serology and PCR) outcome, considering two endpoints: primary blood infection clearance and clinical response at ~28 days, and the incidence of recurrent blood infection during 12 months. Parasite genotypes of primary/recurrent blood infections were analysed. RESULTS: During the first 28 days, no differences in parasite clearance or clinical outcome were observed between T14 (86 patients) and ISD (67 patients). On day 3, 95 % of patients in both groups showed no blood parasites, and no recurrences were detected on days 7-28. Contrarily, the therapeutic effectiveness (absence of recurrent parasitaemia) was distinct for T14 versus ISD at 12 months: 83.7 versus 50 %, respectively (p = 0.000). Symptomatic and asymptomatic infections were recorded on days 31-352. Some parasite recurrences were detected by PCR and/or serological testing. CONCLUSIONS: T14 was effective for opportune elimination of the primary blood infection and preventing relapse episodes. The first single dose of CQ-PQ eliminated primary blood infection as efficiently as the initial three-dose scheme of T14, but the ISD regimen should be abandoned. A single combined dose administered to symptomatic patients in remote areas while awaiting parasitological diagnosis may contribute to halting P. vivax transmission. Alternatives for meeting the challenge of T14 supervision are discussed. TRIAL REGISTRATION: NIH-USA, ClinicalTrial.gov Identifier: NCT02394197.
Asunto(s)
Antimaláricos/administración & dosificación , Cloroquina/administración & dosificación , Malaria Vivax/tratamiento farmacológico , Primaquina/administración & dosificación , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Pruebas Diagnósticas de Rutina , Quimioterapia Combinada/métodos , Femenino , Genotipo , Humanos , Lactante , Malaria Vivax/parasitología , Malaria Vivax/patología , Masculino , México , Persona de Mediana Edad , Plasmodium vivax/clasificación , Plasmodium vivax/genética , Plasmodium vivax/aislamiento & purificación , Recurrencia , Resultado del Tratamiento , Adulto JovenRESUMEN
BACKGROUND: In southern Mexico, malaria transmission is low, seasonal, and persistent. Because many patients are affected by two or more malaria episodes caused by Plasmodium vivax, we carried out a study to determine the timing, frequency, and genetic identity of recurrent malaria episodes in the region between 1998 and 2008. METHODS: Symptomatic patients with more than one P. vivax infection were followed up, and blood samples were collected from primary and recurrent infections. DNA extracted from infected blood samples was analyzed for restriction fragment length polymorphism (RFLP) in genes encoding csp and msp3α, as well as size variation in seven microsatellites. RESULTS: One hundred and forty six parasite samples were collected from 70 patients; of these, 65 patients had one recurrent infection, four had two, and one had three recurrent infections. The majority of recurrent infections occurred within one year of the primary infection, some of which were genetically homologous to the primary infection. As the genetic diversity in the background population was high, the probability of homologous re-infection was low and the homologous recurrences likely reflected relapses. These homologous recurrent infections generally had short (< 6 months) or long (6-12 months) intervals between the primary (PI) and recurrent (RI) infections; whereas infections containing heterologous genotypes had relatively longer intervals. The epidemiological data indicate that heterologous recurrences could be either relapse or re-infections. CONCLUSIONS: Genetic and temporal analysis of P. vivax recurrence patterns in southern Mexico indicated that relapses play an important role in initiating malaria transmission each season. The manifestation of these infections during the active transmission season allowed the propagation of diverse hypnozoite genotypes. Both short- and long-interval relapses have contributed to parasite persistence and must be considered as targets of treatment for malaria elimination programs in the region to be successful.
Asunto(s)
Malaria Vivax/epidemiología , Malaria Vivax/parasitología , Plasmodium vivax/clasificación , Plasmodium vivax/genética , Adolescente , Adulto , Anciano , Animales , Sangre/parasitología , Niño , Dermatoglifia del ADN , ADN Protozoario/genética , ADN Protozoario/aislamiento & purificación , Femenino , Genotipo , Humanos , Masculino , México/epidemiología , Repeticiones de Microsatélite , Persona de Mediana Edad , Epidemiología Molecular , Plasmodium vivax/aislamiento & purificación , Polimorfismo de Longitud del Fragmento de Restricción , Recurrencia , Adulto JovenRESUMEN
Soil moisture is the key link among hydroecological compartments, responding dynamically to sequences of atmospheric processes and management conditions and modulating physical, chemical, and biological processes in the soil. Currently, there are a variety of monitoring techniques to measure, directly or indirectly, the soil moisture. However, some practical issues remain open like the definition a priori of the number, location and depth of the monitoring points, and the impact of failing or poor performance soil moisture sensors. Here, we present a set of techniques, namely Δθ time series, wavelet filtering, and time stability, to identify representative points and monitoring depths through an analysis of hourly soil moisture time series for different configuration of the monitoring network. We used real data from a monitoring network consisting of seven monitoring points, each one with four EC-5 probes (Decagon Devices Inc., Pullman, WA) at 20, 40, 60, and 100 cm. The use of simple time series of Δθ allowed us to assess the spatiotemporal influence of the monitoring points, while the wavelet periodograms allowed us to get insight about the response of the monitoring points at different time scales. Both methods are easy to implement or adapt to specific conditions, being coherent to the results derived from time stability analysis. For our case study, we concluded that we could reallocate 16 sensors (out of 28) without a significant loss of information. However, the final decision strongly relies on a deep knowledge of the site features and the objectives of the monitoring network.
Asunto(s)
Monitoreo del Ambiente/métodos , Suelo/química , Agua/análisis , Chile , Monitoreo del Ambiente/instrumentaciónRESUMEN
The polymorphism of Pvs25 and Pvs28 ookinete surface proteins, their association to circumsporozoite protein repeat (CSPr) genotypes (Vk210 and Vk247) and their infectivity to local Anopheles albimanus and Anopheles pseudopunctipennis were investigated in Plasmodium vivax-infected blood samples obtained from patients in Southern Mexico. The pvs25 and pvs28 complete genes were amplified, cloned and sequenced; and the CSPr genotype was determined by PCR amplification and hybridization. The amino acid Pvs25 and Pvs28 polymorphisms were mapped to their corresponding protein structure. Infected blood samples were simultaneously provided through artificial feeders to both mosquito species; the ratio of infected mosquitoes and oocyst numbers were recorded. The polymorphism of pvs25 and pvs28 was limited to few nucleotide positions, and produced three haplotypes: type A/A parasites presented Pvs25 and Pvs28 amino acid sequences identical to that of Sal I reference strain; parasites type B1 presented a mutation 130 Ile-->Thr in Pvs25, while type B2 presented 87 Gln-->Lys/130 Ile-->Thr in the same molecule. Both types B1 and B2 parasites presented changes in Pvs28 at 87 Asn-->Asp, 110 Tyr-->Asn and five GSGGE/D repeat sequences between the fourth EGF-like domain and the GPI. Most P. vivaxparasites from the coastal plains and the overlapping region were Pvs25/28 A/A, CSPrVk210 and were infective only to An. albimanus (p< or =0.0001). Parasites originating in foothills were Pvs25/28 type B1/B or B2/B and CSPrVk210 or Vk247, and were more infective to An. pseudopunctipennis than to An. albimanus (p< or =0.001). These results and the analysis of Pvs25/28 from other parts of the world indicated that non-synonymous variations in these proteins occur in amino acid residues exposed on the surface of the proteins, and are likely to interact with midgut mosquito ligands. We hypothesize that these molecules have been shaped by co-evolutionary adaptations of parasites to their susceptible vectors.