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Saxitoxin (STX) represents a marine toxin of significant concern due to its deleterious implications for aquatic ecosystems and public food safety. As a potent paralytic agent, the role of STX in obstructing voltage-gated sodium channels (VGSCs) is well-characterized. Yet, the mechanistic details underlying its low-dose toxicity remain largely enigmatic. In the current study, zebrafish embryos and larvae were subjected to subchronic exposure of graded STX concentrations (0, 1, 10, and 100 µg/L) until the 7th day post-fertilization. A tactile stimulus-based assay was employed to evaluate potential behavioral perturbations resulting from STX exposure. Both behavioral and transcription level analyses unveiled a compromised tactile response, which was found to be associated with a notable upregulation in the mRNA of two distinct VGSC isoforms, specifically the scn8aa/ab and scn1Laa/ab transcripts, even at the minimal STX dose. Notably, exposure to this lowest STX concentration also resulted in alterations in the transcriptional patterns of pivotal genes for cholinergic and GABAergic pathways, including ache and gabra1. Furthermore, STX induced a marked decrease in the levels of the neurotransmitter GABA. Our findings underscore that prolonged low-dose STX exposure during early development can significantly compromise the tactile response behavior in zebrafish. This study reveals that chronic low-dose STX exposure of developing zebrafish alters neurotransmission pathways that converge on altered tactile behavior.

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Anilius scytale is the sister lineage of all other alethinophidian snakes. Morphology of the hind limb complex in adult A. scytale (Aniliidae) has been documented. We herein, for the first time, describe the embryology of the skeletal elements of its hind limb and pelvic girdle and contextualize the evolution of these structures. We identified pregnant females of A. scytale in the Herpetology Collection of the Museu Paraense Emílio Goeldi and separated 40 embryos. The embryos were sequentially staged using external and internal anatomy, collectively comprising a developmental series representing six stages. We cleared-stained one specimen of stages 31, 34, 36, and 37. Using the embryological information gleaned from A. scytale, we reinterpret evidence relating to the ossification of the pelvis and hindlimbs. In A. scytale hindlimb buds develop as transient structures that developed before Stage 30 and regresses in subsequent stages. There is no external or internal evidence of the forelimb or scapular girdle. From Stage 31 onwards the ischium, pubis, ilium, femur and zeugopodial cartilages are visible. Pubis and femur ossify towards the end of embryonic life, and cloacal spurs do not develop in the embryo. Skeletal elements of the hindlimb and pelvic girdle develop initially in the ventral zone of the cloaca-tail region. In subsequent stages the hindlimb and pelvic girdle elements migrate dorsally, with the pubis/ischium positioned medial to the ribs. A similar process may be associated with the achievement of the condition of the pelvic girdle in adults of scolecophidians, pythonids and boids.

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BACKGROUND: Bothrops atrox is a pit viper with a loreal pit organ, and its embryological development remains undescribed. Here, we provide a comprehensive description of the embryology of B. atrox, focusing on the loreal pit organ and cephalic scales. RESULTS: We characterized 13 developmental stages of B. atrox based on external features consistent with the embryogenesis of previously described snake species. The loreal pit organ originates from the circumorbital region and migrates to its final position. In Crotalinae, the pit organ first becomes visible at stage 28, whereas in Pythonidae labial, pit organs appear at Stage 35. Pit organs evolved independently three times in Serpentes, encompassing Boidae, Pythonidae, and Crotalinae. Boidae lacks embryological information for pit organs. Furthermore, we observed that head scalation onset occurs at Stage 33 in B. atrox, with fusion of scales surrounding the loreal pit organ. CONCLUSIONS: The embryology of pit organs in Pythonidae and Boidae species remains poorly understood. Our detailed embryological descriptions are critical for proposing developmental scenarios for pit organs and guiding future research on these structures.

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Abstract Introduction The COVID-19 pandemic caused the cessation of academic activities from the face-to-face format to confinement and virtual classes, in which little is studied about its effect on mental health. Objective Determine levels of depression, anxiety, and stress in medical students in Mexico and Colombia during the COVID-19 pandemic. Furthermore, depression, anxiety, and stress were compared by gender, education status, and country. Method A cross-sectional study was carried out with 426 medical students. Data was collected using an online survey containing the Depression, Anxiety, Stress Scale (DASS-21) questionnaire. Results Overall scores for depression, anxiety, and stress were 6.7 ± 1.2, 8.8 ± 1.2, and 5.6 ± 1.2, respectively. Females had significantly higher overall scores for depression (.24-fold increase), anxiety (.25-fold increase), and stress (.40-fold increase) than males (p ≤ .01). The risk for anxiety and stress by school year showed that basic years were associated with higher scores than advanced years (.25 and .38-fold increase, respectively). For females, starting medical school did show an increased risk of depression when compared to male students in their basic years (.38-fold increase). Lastly, students from Mexico had an increased risk for depression and anxiety (p ≤ .022 and p ≤ .004, respectively) but not for stress (p ≤ .402), when compared to students from Colombia. Discussion and conclusion Significant anxiety and depression were observed in medical students from Mexico and Colombia. Factors associated with an increased risk of depression and anxiety are students in their basic years as well as being female.

Resumen Introducción La pandemia de COVID-19 provocó el cese de las actividades académicas desde el formato presencial al confinamiento de las clases virtuales, de las que poco se ha estudiado sobre su efecto en la salud mental. Objetivo Determinar los niveles de depresión, ansiedad y estrés en estudiantes de medicina de México y Colombia durante la pandemia de COVID-19; además de comparar depresión, ansiedad y estrés por género, nivel educativo y país. Método Se realizó un estudio transversal con 426 estudiantes de medicina. Los datos se recopilaron mediante una encuesta en línea que contenía el cuestionario DASS-21. Resultados Las puntuaciones generales de depresión, ansiedad y estrés fueron 6.7 ± 1.2, 8.8 ± 1.2 y 5.6 ± 1.2, respectivamente. Las mujeres tuvieron puntajes generales significativamente más altos para depresión (.24-fold increase), ansiedad (.25-fold increase) y estrés (.40-fold increase). El riesgo de ansiedad y estrés por año escolar mostró que los años básicos se asociaron con puntajes más altos que los estudiantes en años los avanzados (.25 y .38-fold increase). Para las mujeres, cursar años básicos mostró un mayor riesgo de depresión en comparación con los estudiantes varones (.38-fold increase). Por último, los estudiantes mexicanos tuvieron un mayor riesgo de depresión y ansiedad (p ≤ .022 y p ≤ .004, respectivamente) pero no de estrés (p ≤ .402) en comparación con los estudiantes Colombianos. Discusión y conclusión Se observó ansiedad y depresión significativas en estudiantes de medicina mexicanos y colombianos. Los factores asociados a un mayor riesgo de depresión y ansiedad fueron; ser estudiante en años básicos además de ser mujer.

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Introducción: los pacientes pediátricos y sus padres sienten ansiedad antes de una cirugía, síntoma que afecta la inducción anestésica, el dolor y el comportamiento postoperatorio. El objetivo fue evaluar el efecto de la educación preoperatoria estructurada en el nivel de ansiedad de niños sometidos a cirugía electiva y de sus padres. Métodos: estudio prospectivo, aleatorio, doble ciego, en niños de 2-12 años, ASA I-II. Los participantes fueron aleatorizados en grupo control (información habitual) y grupo experimental (información estructurada). Se registraron variables demográficas, nivel de ansiedad en unidad preoperatoria y en pabellón en niños y padres; se evaluó el comportamiento de los niños durante la inducción anestésica. Análisis estadístico: t-test, x2; valores expresados en media y desviación estándar; significancia p ≤ 0,05. Resultados: se reclutaron 34 pacientes, 18 en grupo control y 16 en grupo experimental. Los valores ansiedad en niños pre-pabellón fueron 37,7 ± 21,4 en grupo control y 31,9 ± 11,5 en grupo experimental (p= 0,35); durante pre-inducción fue 43,2 ± 25,3 y 36 ± 15,5 respectivamente (p= 0,33). Los niveles de ansiedad en padres pre-pabellón fueron 42,5 ± 15,5 para grupo control y 37,6 ± 6,9 en grupo experimental (p= 0,25), y al retirarse del pabellón fueron de 45,1 ± 16,6 y 43,9 ± 9,8 respectivamente (p= 0,82). No hubo diferencias en el comportamiento durante la inducción anestésica entre ambos grupos (p= 0,24). Conclusiones: no fue posible demostrar efectos de información estructurada en niveles de ansiedad en niños que van a ser operados y en sus padres.

Introduction: Pediatric patients and their parents experience anxiety before surgery, a symptom that affects anesthetic induction, pain and postoperative behavior. The objective was to evaluate the effect of structured preoperative education on the anxiety level in children undergoing elective surgery and their parents. Methods: A prospective, randomized, double-blind study in children aged 2-12 years, ASA I-II. Patients were randomized into a control group (usual preoperative information) and an experimental group (structured information). Demographic variables, anxiety level in the preoperative unit and in operating room in children and parents were recorded; the behavior of children during anesthetic induction was evaluated. Statistical analysis: t-test, x2; values expressed as mean and standard deviation; significance p ≤ 0.05. Results: 34 patients were recruited, 18 in the control group and 16 in the experimental group. The anxiety levels in children in preoperative unit were 37.7 ± 21 and 31.9 ± 11.5.4 in control and experimental group, respectively (p = 0.35), and in operating room were 43.2 ± 25.3 and 36 ± 15.5 respectively (p = 0.33). Parental anxiety levels in preoperative unit were 42.5 ± 15.5 in control group and 37.6 ± 6.9 in experimental group (p = 0.25), and when they leaving operating room were 45.1 ± 16.6 and 43.9 ± 9.8 respectively (p = 0.82). There were no differences in the behavior during anesthetic induction between both groups (p = 0.24). Conclusions: It was not possible to demonstrate effects of structured information on anxiety levels in children undergoing surgery and in their parents.

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Oxidative stress plays an important role in vascular complications observed in patients with obesity and Type 2 Diabetes (T2D). Xanthine oxidase (XO) breaks down purine nucleotides into uric acid and contributes to the production of reactive oxygen species (ROS). However, the relationship between XO activity and glucose homeostasis in T2D subjects with obesity is unclear. We hypothesized that disordered glucose levels are associated with serum XO activity in overweight women and men with T2D and without hyperuricemia. We studied serum XO activity in women and men with and without T2D. Our results show that serum XO activity was greater in T2D patients with body mass index (BMI) ≥ 25 kg/m2 than in those with BMI < 25 kg/m2 (p < 0.0001). Sex-based comparative analyses of overweight T2D patients showed that serum XO activity correlated with homeostasis model assessment of ß-cell function (HOMA-ß), fasting plasma glucose (FPG), and hemoglobin A1C in overweight T2D women but not in overweight T2D men. In addition, as compared to overweight T2D men, women had higher high-sensitivity C-reactive protein (hs-CRP) levels. However, overweight T2D men had higher XO activity and uric acid levels than women. Our results suggest that XO activity is higher in overweight T2D patients, especially in men, but is more sensitive to disordered glucose levels in overweight women with T2D.

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Undiagnosed type 2 diabetes (T2D) remains a major public health concern. The global estimation of undiagnosed diabetes is about 46%, being this situation more critical in developing countries. Therefore, we proposed a non-invasive method to quantify glycated hemoglobin (HbA1c) and glucose in vivo. We developed a technique based on Raman spectroscopy, RReliefF as a feature selection method, and regression based on feed-forward artificial neural networks (FFNN). The spectra were obtained from the forearm, wrist, and index finger of 46 individuals. The use of FFNN allowed us to achieve an error in the predictive model of 0.69% for HbA1c and 30.12 mg/dL for glucose. Patients were classified according to HbA1c values into three categories: healthy, prediabetes, and T2D. The proposed method obtained a specificity and sensitivity of 87.50% and 80.77%, respectively. This work demonstrates the benefit of using artificial neural networks and feature selection techniques to enhance Raman spectra processing to determine glycated hemoglobin and glucose in patients with undiagnosed T2D.

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OBJECTIVE: This study analyzes the effects of the Pedernales earthquake (April 2016) on Ecuador's health care system. METHODS: A research was carried out in Chone Canton, which combined documentary, quantitative, and qualitative techniques. Epidemiological and service production information taken from official documents was analyzed systematically. In-depth interviews and surveys were conducted with health care program directors and technicians from the Health Centres of the Ministry of Public Health and the users. RESULTS: Deficiencies in the health care system were already observed in Chone Canton prior to the earthquake mainly due to the lack of doctors, nurses, and hospital beds. According to the interviewees, the health district was not prepared for an emergency like the earthquake. Some buildings fell after the earthquake, and Chone Hospital was disabled. These problems coupled with preventive action failures at the community level led to an increase in diseases after the earthquake. CONCLUSIONS: The shortage of personnel and physical infrastructure, weaknesses in primary health care in the Ecuadorian health system, the lack of preparation, and limited availability of information on health indicators were the causes of the sharp increase in pre-existing diseases in the area, and of new epidemic outbreaks after the earthquake.

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OBJECTIVES: Evaluate the relevance of the coronavirus disease 2019 (COVID-19) positive case detection policy or model implemented by the Ministry of Public Health (MPH) of Ecuador and to compare it with the experiences of other countries. METHODS: Data contained the daily reports publicized by the MPH. The formulations were carried out under the Conditioned Probability modality applying Bayes' Theorem. All the COVID-19 tests applied in relation to the confirmed cases per million inhabitants were considered to obtain their level of positivity, and compared with the experience of Iceland and South Korea. RESULTS: The probability of detecting positive cases of COVID-19 in Ecuador was higher than Iceland and South Korea, because the diagnostic tests were aimed at symptomatic patients, without identifying asymptomatic or mild symptomatic, who play an important role in the transmission of the disease. In addition, many symptomatic patients were examined but will remain undiagnosed due to the unavailability of tests and the low quality of many of them. CONCLUSIONS: The daily reports on the behavior of the COVID-19 issued by the Ecuadorian government do not adequately represent the growth in the number of those infected each day, nor the actual behavior of the epidemic, affecting possible control measures.

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Morphological stasis is generally associated with relative constancy in ecological pressures throughout time, producing strong stabilizing selection that retains similar shared morphology. Although climate and vegetation are commonly the main key factors driving diversity and phenotypic diversification in terrestrial vertebrates, fossorial organisms have their morphology mostly defined by their fossorial lifestyle. Among these secretive fossorial organisms, blind snakes of the South American genus Amerotyphlops are considered poorly studied when compared to other taxa. Here, we evaluate the cryptic diversity of Amerotyphlops using phylogenetic and multivariate approaches. We based our phylogenetic analysis on a molecular dataset composed of 12 gene fragments (eight nuclear and four mitochondrial) for 109 species of Typhlopidae. The multivariate analysis was implemented using 36 morphological variables for 377 specimens of Amerotyphlops. Additionally, we contrast our phylogenetic result with the morphological variation found in cranial, external and hemipenial traits. Our phylogenetic results recovered with strong support the following monophyletic groups within Amerotyphlops: (1) a clade formed by A. tasymicris and A. minuisquamus; (2) a clade composed of A. reticulatus; (3) a north-eastern Brazilian clade including A. yonenagae, A. arenensis, A. paucisquamus and A. amoipira; and (4) a clade composed of A. brongersmianus and a complex of cryptic species. Based on these results we describe four new species of Amerotyphlops from north-eastern and south-eastern Brazil, which can be distinguished from the morphologically similar species, A. brongersmianus and A. arenensis.