Dicer regulates Nosema ceranae proliferation in honeybees.

Nosema ceranae is a microsporidian parasite that infects the honeybee midgut epithelium. The protein-coding gene Dicer is lost in most microsporidian genomes but is present in N. ceranae. By feeding infected honeybees with small interfering RNA targeting the N. ceranae gene coding Dicer (siRNA-Dicer), we found that N. ceranae spore loads were significantly reduced. In addition, over 10% of total parasite protein-coding genes showed significantly divergent expression profiles after siRNA-Dicer treatment. Parasite genes for cell proliferation, ABC transporters and hexokinase were downregulated at 3 days postinfection, a key point in the middle of parasite replication cycles. In addition, genes involved in metabolic pathways of honeybees and N. ceranae showed significant co-expression. Furthermore, the siRNA-Dicer treatment partly reversed the expression patterns of honeybee genes. The honeybee gene mucin-2-like showed significantly upregulation in the siRNA-Dicer group compared with the infection group continually at 4, 5 and 6 days postinfection, suggesting that the siRNA-Dicer feeding promoted the strength of the mucus barrier resulted from interrupted parasite proliferation. As the gene Dicer broadly regulates N. ceranae proliferation and honeybee metabolism, our data suggest the RNA interference pathway is an important infection strategy for N. ceranae.

Characteristics and impacts of peer assisted learning in university studies in health science: A systematic review.

OBJECTIVE: Systematically analyse the characteristics and impact of peer assisted learning programmes implemented in undergraduate health education. METHODS: Following the PRISMA protocol, we searched the electronic indexed databases WoS and SCOPUS; original studies reporting peer assisted learning in health science careers were included in the systematic review. Among them, the studies between 2010 and January 2020 were selected, and information regarding programme structures and principal results was subsequently extracted. RESULTS: A total of 47 studies were included in the review. The most frequent programme characteristics were the near-peer teaching modality, lecture classes, clinical laboratories and peer tutor training. The main findings identified were benefits in tutors' confidence and knowledge, better student comprehension and a more comfortable learning environment in comparison with that established by academic tutors. CONCLUSION: Peer assisted learning programmes have shown qualitative benefits in the learning environment, generation of support networks and confidence in knowledge acquired. Nonetheless, quantitative benefits measured as improvements in marks are inconclusive. Future studies are needed to standardise the methodologies used to determine which characteristics are the most positive in the learning process.

Características e impactos del aprendizaje entre pares en estudios universitarios en ciencias de la salud: una revisión sistemática / Characteristics and impacts of peer assisted learning in university studies in health science: A systematic review

Objetivo: Analizar sistemáticamente las características y los impactos de los programas e iniciativas de aprendizaje asistido por pares realizados en estudios universitarios en ciencias de la salud en los cursos de pregrado. Métodos: Siguiendo el protocolo PRISMA, se realizó una búsqueda en las bases de datos indexadas en WoS y SCOPUS, con todos los trabajos originales que reportan aprendizaje asistido por pares en estudios universitarios en ciencias de la salud. Se seleccionaron artículos originales entre enero de 2010 y enero de 2020, analizando la información sobre las características de los programas y los principales resultados e impactos de los estudios. Resultados: Se incluyeron 47 estudios en la revisión. Las características de los programas más representadas fueron la utilización de la modalidad aprendizaje entre pares próximos, el uso de clases teóricas, laboratorios clínicos y la capacitación a los tutores pares. Los principales impactos identificados son los beneficios en la confianza y en el conocimiento de los tutores, la mejor comprensión de los contenidos y la mayor comodidad en comparación con los tutores académicos en los estudiantes. Conclusión: Los programas de aprendizaje asistido por pares han demostrado beneficios cualitativos relativos al ambiente de aprendizaje, la generación de redes de apoyo y la confianza en los conocimientos adquiridos. Sin embargo, los beneficios cuantitativos, medidos como mejoría en las calificaciones, no son concluyentes. Se necesitan futuros estudios que busquen indagar sobre las metodologías utilizadas para detectar qué características impactan más positivamente sobre el proceso de aprendizaje (AU)

Objective: Systematically analyse the characteristics and impact of peer assisted learning programmes implemented in undergraduate health education. Methods: Following the PRISMA protocol, we searched the electronic indexed databases WoS and SCOPUS; original studies reporting peer assisted learning in health science careers were included in the systematic review. Among them, the studies between 2010 and January 2020 were selected, and information regarding programme structures and principal results was subsequently extracted. Results: A total of 47 studies were included in the review. The most frequent programme characteristics were the near-peer teaching modality, lecture classes, clinical laboratories and peer tutor training. The main findings identified were benefits in tutors’ confidence and knowledge, better student comprehension and a more comfortable learning environment in comparison with that established by academic tutors. Conclusion: Peer assisted learning programmes have shown qualitative benefits in the learning environment, generation of support networks and confidence in knowledge acquired. Nonetheless, quantitative benefits measured as improvements in marks are inconclusive. Future studies are needed to standardise the methodologies used to determine which characteristics are the most positive in the learning process (AU)

Exploiting electronic strategies to stabilize a planar tetracoordinate carbon in cyclic aromatic hydrocarbons.

A new approach to stabilize compounds containing a planar tetracoordinate carbon (ptC), embedded in aromatic hydrocarbons, is presented herein. This is achieved by using ligands that promote the formation of a 3c-2e σ-bond with the ptC under two conditions: without altering the sp2 hybridization of the aromatic carbons; and containing empty orbitals perpendicular to the aromatic ring to participate in the aromatic π-electronic delocalization.

Antimicrobial and anti-inflammatory activities, wound-healing effectiveness and chemical characterization of the latex of Jatropha neopauciflora Pax.

ETHNOPHARMACOLOGICAL RELEVANCE: Jatropha neopauciflora Pax is an endemic species to Mexico, and its latex is used in traditional medicine to treat mouth infections when there are loose teeth and to heal wounds. In this research, we evaluated the antimicrobial activity, wound healing efficacy and chemical characterization of J. neopauciflora latex in a murine model. MATERIALS AND METHODS: The antibacterial activity was determined using Gram positive and negative strains, the antifungal activity was determined using yeast and filamentous fungi, and the wound healing efficacy of the latex was determined using the tensiometric method. The anti-inflammatory activity was evaluated using the plantar oedema model in rats, administering the latex orally and topically. Cytotoxic activity was determined in vitro in two different cell lines. Antioxidant capacity, total phenolics, total flavonoids, reducing carbohydrates and latex proteins were quantified. The latex analysis was performed by High Performance Liquid Chromatography (HPLC). Finally, molecular exclusion chromatography was performed. RESULTS: The latex demonstrated antibacterial activity. The most sensitive strains were Gram positive bacteria, particularly S. aureus (MIC=2mg/mL), and the latex had bacteriostatic activity. The latex did not show antifungal activity. The latex demonstrated a wound-healing efficacy, even the positive control (Recoveron). The orally administered latex demonstrated the best anti-inflammatory activity and was not toxic to either of the 2 cell lines. The latex had a high antioxidant capacity (SA50=5.4µg/mL), directly related to the total phenolic (6.9mg GAE/mL) and flavonoid (12.53µg QE/mL) concentration. The carbohydrate concentration was 18.52µg/mL, and fructose was the most abundantly expressed carbohydrate in the latex (14.63µg/mL, 79.03%). Additionally, the latex contained proteins (7.62µg/mL) in its chemical constitution. As secondary metabolites, the HPLC analysis indicated the presence of phenols and flavonoids. CONCLUSIONS: The J. neopauciflora latex promotes the wound healing process by avoiding microorganism infections, inhibiting inflammation and acting as an antioxidant.

IN VIVO AND IN VITRO ANTILEISHMANIAL EFFECTS OF METHANOLIC EXTRACT FROM BARK OF BURSERA APTERA.

BACKGROUND: Cutaneous leishmaniasis lacks effective and well-tolerated treatments. The current therapies mainly rely on antimonial drugs that are inadequate because of their poor efficacy. Traditional medicine offers a complementary alternative for the treatment of various diseases. Additionally, several plants have shown success as anti-leishmanial agents. Therefore, we sought to evaluate the in vitro and in vivo activity of MEBA against Leishmania mexicana. MATERIALS AND METHODS: Methanolic extract of B. aptera was obtained by macetration, after we determined in vitro anti-leishmanial activity of MEBA by MTT assay and the induced apoptosis in promastigotes by flow cytometry. To analyze the in vivo anti-leishmanial activity, we used infected mice that were treated and not treated with MEBA and we determined the levels of cytokines using ELISA. The phytochemical properties were determined by CG-MS and DPPH assay. RESULTS: We determined of LC50 of 0.408 mg/mL of MEBA for in vitro anti-leishmanial activity. MEBA induced apoptosis in promastigotes (15.3% ± 0.86). Treated mice exhibited smaller lesions and contained significantly fewer parasites than did untreated mice; in addition, we found that IFN-γ and TNF-α increased in the sera of MEBA-treated mice. GC-MS analysis showed that podophyllotoxin was the most abundant compound. Evaluation of the activity by DPPH assay demonstrated an SC50 of 11.72 µg/mL. CONCLUSION: Based on the above data, it was concluded that MEBA is a good candidate in the search for new anti-leishmanial agents.

An epidemiological study of familial neurocysticercosis in an endemic Mexican community.

Neurocysticercosis (NC) caused by Taenia solium is a frequent parasitic disease of the central nervous system. It is highly endemic in many developing countries, where many people are exposed but few become infected. Here, the relevance of age, gender, and genetic and exposure factors on NC susceptibility was studied in 649 inhabitants of a rural community of Mexico. Endemicity was confirmed by the high prevalence of pig cysticercosis (32.8%) and human seroprevalence (43.8%). Human NC cases were diagnosed by computerised tomography scans. A questionnaire to evaluate risk factors was applied and familial relationships between participants were registered. An overall NC frequency of 9.1% (59/649) was found. NC frequency increased with age but did not associate with gender. Most NC cases were asymptomatic. None of the evaluated risk factors were associated with NC. No familial aggregation was detected when studying all cases, although a significant relationship between mother and child in cases with multiple parasites was found. These findings point to the fact that human NC in high exposure conditions is not simply related to exposure factors and they do not support the participation of a major gene in single-cyst NC. Rather, our results point to a complex interaction of genetic and environmental factors involved in NC.

Correlation among Poincaré plot indexes and time and frequency domain measures of heart rate variability.

PRIMARY OBJECTIVE: In order to corroborate the rported performance advantage of Poincaré plot indexes as autonomic activity markers, the correlation among these indexes and those computed from the time and frequency domains were obtained. METHODS AND PROCEDURES: Starting from the RR series derived from the ECG of 21 healthy volunteers during five manoeuvres, longitudinal (L), transverse (T) axis, and autocorrelation (r) from Poincaré plots, rMSSD and standard deviation (SD) in the temporal domain, and frequency domain indexes were computed. MAIN OUTCOMES AND RESULTS: Poincaré plot indexes were correlated in a better way with the time indexes, rather than the spectral measures. A strong correlation (0.997) between L and SD was observed, while an underlying mathematical relationship was established for T vs rMSSD. CONCLUSIONS: Poincaré plot indexes may be considered as equivalent or surrogates of the temporal ones, and they do not have a better performance as autonomic markers.

Reproducibility of heart rate variability from short-term recordings during five manoeuvres in normal subjects.

PRIMARY OBJECTIVE: Due to limited and contradictory information available, the reproducibility of temporal and spectral measurements of heart rate variability from short-term recordings was evaluated in normal subjects during supine, controlled breathing, standing, exercise and recovery conditions. METHODS AND PROCEDURES: Five-minute tachograms from 11 individuals were obtained during the specified manoeuvres, and repeated three times in a five day period. Besides temporal and spectral indexes, the central frequencies were also computed. MAIN OUTCOMES AND RESULTS: The ANOVA presented non-significant differences among the repetitions for any of the parameters studied. Most intra-class correlation coefficients were over 0.68. The central frequency of the low component diminished during the manoeuvres. CONCLUSIONS: In healthy individuals, the temporal and spectral measurements of the heart rate variability from short-term records are stable in a five day period for the manoeuvres studied. Central frequencies of the spectral components might be used as indexes of the autonomic activity.