A Sea Anemone Lebrunia neglecta Venom Fraction Decreases Boar Sperm Cells Capacitation: Possible Involvement of HVA Calcium Channels.

Sea anemones produce venoms characterized by a complex mixture of low molecular weight compounds, proteins and peptides acting on voltage-gated ion channels. Mammal sperm cells, like neurons, are characterized by their ion channels. Calcium channels seem to be implicated in pivotal roles such as motility and capacitation. In this study, we evaluated the effect of a low molecular weight fraction from the venom of the sea anemone Lebrunia neglecta on boar sperm cells and in HVA calcium channels from rat chromaffin cells. Spermatozoa viability seemed unaffected by the fraction whereas motility and sperm capacitation were notoriously impaired. The sea anemone fraction inhibited the HVA calcium current with partial recovery and no changes in chromaffin cells' current kinetics and current-voltage relationship. These findings might be relevant to the pharmacological characterization of cnidarian venoms and toxins on voltage-gated calcium channels.

Clinical and Epidemiological Characteristics of Paediatric Patients Diagnosed with COVID-19 in a Tertiary Hospital in Mexico City.

COVID-19 affects the paediatric population less frequently than adults. A retrospective study was performed in a tertiary paediatric hospital in Mexico City in children <18 years of age who were hospitalized with a positive reverse transcription-polymerase chain reaction for SARS-CoV-2. Included in the study were 86 patients with a median age of 10 years old (IQR 2.6-14.3 years), who were classified in three groups: previously healthy, with chronic disease and immunosuppressed patients. The principal signs and symptoms were fever (81%), cough (51%) and headache (35%). A total of 20 patients (23%) required management in the paediatric intensive care unit (PICU) and 17% needed mechanical ventilation for an average of 12.7 days (IQR 2-29 days). There was no statistically significant difference between the three clinical classification groups in those patients admitted to the PICU, most of which were previously healthy patients. The mortality rate was 5% (four patients). Given that the paediatric population is susceptible to infection, potential transmitters and to clinical presentations with variable degrees of severity, it is important to continue reinforcing social distancing measures.

Perfil de ingreso de los estudiantes de la Licenciatura en Enfermería en una Institución de Educación Superior / Entry profile of students of the Nursing Degree in a Higher Education Institution

Resumen

Introducción: en la medida en que el sistema de educación superior logre tener mayor información sobre el perfil de los estudiantes, autoridades y profesores estarán en mejores condiciones de cumplir con los objetivos esenciales de la educación.

Objetivo: describir y analizar las características de los estudiantes que ingresan a la Licenciatura en Enfermería en una institución de educación superior.

Metodología: estudio transversal analítico, con 469 alumnos de dos generaciones, previo consentimiento informado se aplicó un cuestionario sobre las características personales, familiares, socioeconómicas y escolares. El análisis fue con el programa estadístico SPSS versión 21, Chi cuadrada y t de student.

Resultados: se encontró asociación entre el sentirse a gusto con la Licenciatura en Enfermería y la elección de la carrera p = 0.000; así como con el deseo de cambiarse de carrera p = 0.000 y con el deseo de estudiar un posgrado en Enfermería p = 0.014. No existe relación entre el promedio del bachillerato y el sexo de los alumnos p = 0.108, con el deseo del alumno para realizar estudios de posgrado p = 0.032, con el espacio para el estudio en casa p = 0.064, ni con el acceso a Internet p = 0.822.

Conclusiones: los factores que facilitan u obstaculizan al estudiante en su tránsito por la licenciatura son: el promedio de bachillerato, las horas de estudio y el gusto por la carrera; así como: el nivel socioeconómico bajo y el grado académico y ocupación de los padres.

Abstract

Introduction: To the extent that the higher education system achieves greater information on the profile of students, authorities and teachers will be better able to meet the essential objectives of education.

Objective: Describe and analyze the characteristics of the students that enter the Nursing Degree in a Higher Education Institution.

Methods: Cross-sectional analytical study, with 469 students from two generations, with prior informed consent, a questionnaire was applied on personal, family, socioeconomic and school characteristics. The analysis was with the SPSS version 21, Chi squared test and Student t test.

Results: An association was found between feeling comfortable with the nursing degree and the choice of career p = 0.000; as well as, with the desire to change career p = 0.000 and with the desire to study a postgraduate nursing degree p = 0.014. There is no relationship between the average of the baccalaureate and the sex of the students p = 0.108; with the desire of the student to carry out postgraduate studies p = 0.032; with the space for home study p = 0.064; and with the Internet access p = 0.822.

Conclusions: The factors that facilitate or hinder the student in their transition through the bachelor's degree are: the high school average, the hours of study and the taste for the career; as well as, the low socioeconomic level and the academic degree and occupation of the parents.

Focal adhesion kinase is required for actin polymerization and remodeling of the cytoskeleton during sperm capacitation.

Several focal adhesion proteins are known to cooperate with integrins to link the extracellular matrix to the actin cytoskeleton; as a result, many intracellular signaling pathways are activated and several focal adhesion complexes are formed. However, how these proteins function in mammalian spermatozoa remains unknown. We confirm the presence of focal adhesion proteins in guinea pig spermatozoa, and we explore their role during capacitation and the acrosome reaction, and their relationship with the actin cytoskeleton. Our results suggest the presence of a focal adhesion complex formed by ß1-integrin, focal adhesion kinase (FAK), paxillin, vinculin, talin, and α-actinin in the acrosomal region. Inhibition of FAK during capacitation affected the protein tyrosine phosphorylation associated with capacitation that occurs within the first few minutes of capacitation, which caused the acrosome reaction to become increasingly Ca(2+) dependent and inhibited the polymerization of actin. The integration of vinculin and talin into the complex, and the activation of FAK and paxillin during capacitation, suggests that the complex assembles at this time. We identify that vinculin and α-actinin increase their interaction with F-actin while it remodels during capacitation, and that during capacitation focal adhesion complexes are structured. FAK contributes to acrosome integrity, likely by regulating the polymerization and the remodeling of the actin cytoskeleton.

SrMnO3 Thermochromic Behavior Governed by Size-Dependent Structural Distortions.

The influence of particle size in both the structure and thermochromic behavior of 4H-SrMnO3 related perovskite is described. Microsized SrMnO3 suffers a structural transition from hexagonal (P63/mmc) to orthorhombic (C2221) symmetry at temperature close to 340 K. The orthorhombic distortion is due to the tilting of the corner-sharing Mn2O9 units building the 4H structural type. When temperature decreases, the distortion becomes sharper reaching its maximal degree at ∼125 K. These structural changes promote the modification of the electronic structure of orthorhombic SrMnO3 phase originating the observed color change. nano-SrMnO3 adopts the ideal 4H hexagonal structure at room temperature, the orthorhombic distortion being only detected at temperature below 170 K. A decrease in the orthorhombic distortion degree, compared to that observed in the microsample, may be the reason why a color change is not observed at low temperature (77 K).

Effect of porcine follicular fluid proteins and peptides on oocyte maturation and their subsequent effect on in vitro fertilization.

The follicular fluid (FF) is a microenvironment that contains molecules involved in oocyte maturation, ovulation, and fertilization. Characterizing the proteins and peptides present in the FF could be useful for determining which proteins and peptides to use as a supplement for culture media. Biologically active peptides produced during the maturation or degradation of functional proteins are called cryptides. The aim of this study was to identify the proteins and cryptides in porcine FF that could stimulate porcine oocyte in vitro maturation (IVM) and in vitro fertilization (IVF) when added to culture maturation medium. Five FF protein fractions (F1-F5) were obtained by ionic exchange chromatography, resolved by SDS-PAGE, and identified by tandem mass spectrometry. These fractions had effects on IVM and/or IVF. The F1 fraction, which was composed of immunoglobulin fragments, cytokeratin, transferrin, and plasminogen precursor increased IVM and IVF. The F2, F3, and F4 fractions reduced the percentage of oocytes in first metaphase. Additionally, the F3 fraction, which was composed of immunoglobulins and transthyretin, interfered with germinal vesicle breakdown. The F5 fraction, which was mainly composed of serum albumin and keratin, favored germinal vesicle breakdown and promoted IVM. Most of the 31 proteins which were associated with the immune response and inflammatory processes could be related to oocyte maturation and fertilization. Some of the identified proteins were present in more than one fraction; this could be explained by a change in their isoelectric points, because of the loss of part of the amino acid sequence or a change in the glycosylation status of the protein. Improved oocyte IVM and IVF will increase embryo production, which in turn will contribute to the efficiency of assisted reproduction in various mammalian species.

Eficiencia terminal de alumnos del Plan Único de Especialización en Enfermería / A longitudinal study of the characteristics and completion efficiency of graduates of the Nursing Specialization Unique Plan

Resumen

Introducción: los procesos de formación en el posgrado requieren de estudios de seguimiento, que aporten datos sobre las características de sus alumnos a su ingreso, permanencia, trayectoria académica, egreso y obtención del grado, su conocimiento contribuye a generar procesos de mejora continua.

Objetivo: identificar las características de ingreso, trayectoria académica y la eficiencia terminal de tres cohortes generacionales de alumnos que ingresaron al Plan Único de Especialización en Enfermería (PUEE), durante los ciclos escolares 2006, 2007 y 2008.

Metodología: estudio descriptivo, observacional, longitudinal de tres generaciones de alumnos inscritos al PUEE. Se presentan, los resultados de la fase cuantitativa, en la que se aplicó un instrumento a los alumnos, que incluyó las dimensiones: datos generales de identificación, condición laboral, antecedentes académicos a nivel licenciatura y posgrado, trayectoria escolar y eficiencia terminal. Los datos de los dos últimos rubros, fueron recuperados de los expedientes de la Coordinación del PUEE. Se empleó el paquete estadístico SPSS, y se aplicaron pruebas de significancia estadística, t Student, χ2, y ANOVA.

Resultados: predomina la población femenina y soltera, las especialidades de Adulto en estado crítico, Infantil, Perinatal y Cardiovascular, tienen mayor demanda, 76 % se encuentran incorporados al mercado laboral desde su ingreso.

Conclusiones: hay congruencia entre los resultados que se observan y otras investigaciones que destacan mayores niveles de formación en el sector de prestación de servicios del sector público.

Abstract

Introduction: the process of post-graduation formation requires followup studies to provide data on student characteristics on enrollment, duration, academic trajectory, and graduation, so that this knowledge can contribute to continuous overall improvement.

Objective: to identify the characteristics of enrollment, academic trajectory, and completion efficiency characteristics in three generational cohorts of students who joined the Nursing Specialization Unique Plan (NSUP) during the 2006, 2007 and 2008 academic cycles.

Methodology: descriptive, observational, longitudinal study of three generations of students from the NSUP. The quantitative-phase results included general data, employment status, academic background at the bachelor's and the pos-graduation level, academic trajectory, and completion efficiency. Data on these last two areas were obtained from the NSPU files. The SPSS was used to obtain Student's t-test, χ2 , and ANOVA statistical significance.

Results: most students were single women. The most in-demand specialties were adult critical care, pediatrics, perinatal, and cardiovascular; 76 % of the students are working since their enrollment in the NPSU.

Discussion: congruency between these results and those of other studies of academic preparation for higher levels in the public sector was found.

Conclusions: better grade point average and greater completion efficiency are related to having work-related scholarships.

La enseñanza del conocimiento práctico de enfermería en escenarios clínicos / Teaching practical knowledge to nurses in real clinical setting

Resumen

Objetivo: indagar las formas que presentan la enseñanza clínica y la transmisión de los saberes prácticos, en los escenarios de práctica, en la formación de las licenciadas en enfermería y obstetricia (LEO) de la Escuela Nacional de Enfermería y Obstetricia (ENEO).

Metodología: estudio, descriptivo de carácter cuantitativo, que empleó como instrumento, un cuestionario estructurado de 50 preguntas que incluyó los aspectos: formación académica de los docentes de enseñanza clínica, experiencia profesional en enfermería, concepción de conocimiento práctico, identidad profesional, métodos de enseñanza empleados y papel de las jerarquías de poder en los procesos de enseñanza y aprendizaje. El instrumento se aplicó a los docentes de enseñanza clínica de la LEO, la población de estudio se compuso de un total de 50 profesores, de los cuáles se obtuvo respuesta del 80 % (n = 40). Los datos fueron procesados a través del programa estadístico SPSS.

Resultados: permiten concluir, que la demostración directa de las acciones (50 %), constituye la principal forma de enseñanza clínica; que si bien los alumnos en su calidad de aprendices, enfrentan las situaciones de práctica con inseguridad (57.5 %), confían en que las enfermeras expertas que los acompañan y supervisan, les ayudarán a resolver las situaciones difíciles.

Discusión: la enseñanza clínica posee las características de techné, concepto definido como aquel conocimiento práctico, que sólo se adquiere por la vía de la experiencia directa.

Summary

Objective: to identified the methods used in nursing clinical teaching and the transmission of practical knowledge in real settings for the training nursing baccalaureate at the National School of Nursing and Obstetric (ENEO).

Methodology: a descriptive study using an instrument with 50 items that contained: academic training of clinic teachers, nursing professional experience, practical knowledge concept, professional identity, teaching method used, and power hierarchy paper in the different process of teaching and learning. The instrument was applied to clinical teachers of Nursing Bachelor. The study population was integrated by 50 teachers, which were obtained the answers of 80 % (n = 40). The data were applied through a descriptive statistical program.

Results: concluded that demonstration of the actions (50 %) was the main way of clinical teaching; and as well students like apprentices, confront practice situations with insecurity (57.5 %), they trust in expertse nurse that accompanied and supervised them, helping to resolve difficult situations.

Discussion: clinical teaching remarks the concept, understood that the practical knowledge only can be acquired by the experience way.

Effects of atrazine and fenoxaprop-ethyl on capacitation and the acrosomal reaction in boar sperm.

Atrazine is a herbicide of the chloro-s-triazine family. It inhibits photosynthesis in plants and is an endocrine disruptor, but its effects on human health are controversial. Fenoxaprop-ethyl, an aryloxy phenoxyalkanoic acid herbicide, inhibits the biosynthesis of fatty acids and provokes depolarization of membranes. The aim of this study is to evaluate the in vitro effects of both herbicides on capacitation, spontaneous acrosome reaction (SAR) and progesterone-induced acrosome reaction (PIAR) in boar sperm. Sperm capacitation is done in TALP-HEPES media for 4 hours. Capacitation and SAR are evaluated immediately; PIAR, 30 minutes later. LC50 for fenoxaprop-ethyl is 60 micromolar [corrected] and 40 micromolar [corrected] for atrazine. Fenoxaprop-ethyl induces capacitation at 60 micromolar [corrected] and SAR at all concentrations, also increases significantly PIAR. Atrazine decreased capacitation whereas increase significantly SAR and PIAR at all concentrations. It seems that fenoxaprop-ethyl and atrazine accelerate the capacitation and the acrosomal reaction, possibly via plasma membrane destabilization.

Carbohydrate affinity chromatography indicates that arylsulfatase-A from capacitated boar sperm has mannose and N-acetylglucosamine/sialic acid residues.

Carbohydrate residues on membrane proteins from sperm are important in gamete interaction. In recent years, Arylsulfatase A (AS-A) has been acquiring an important role from the various putative gamete interaction responsibles in sperm. The aim of this study was to determine if the capacitated boar sperm Arylsulfatase-A (AS-A), contains D-mannose, N-acetylglucosamine and/or sialic acid residues by its purification using affinity chromatography with Concanavalia ensiformis Agglutinin(Con-A) or Wheat Germ Agglutinin (WGA) as ligands. Sperm samples were capacitated in TALP-HEPES medium. Protein extract was added to the affinity columns. Sequencing of retained proteins was done after SDS-PAGE. Total capacitated sperm proteins electrophoresis showed molecular masses between 14 kDa and 102 kDa. A major band of 68 kDa, and 2 minor bands of 52 kDa and 47 kDa were observed. They were AS-A, hyaluronidase and lactadherin, respectively. The Con-A-retained proteins (RP) pattern showed bands from 14 to 98 kDa. After sequencing and BLAST analysis, the 62 kDa band corresponded to Arylsulfatase-A. The WGA RP fraction showed bands from 14 to 100 kDa. The 65 kDa band corresponded to AS-A. This study showed that AS-A has mannose, N-acetylglucosamine and/or sialic acid residues as part of its glycosilation. In this study AS-A was isolated from boar capacitated sperm by affinity chromatography using separately Con-A and WGA, indicating that there are mannose, N-acetylglucosamine and/or sialic acid residues in its glycosilation. AS-A is a membrane protein of capacitated sperm. Further investigation is needed to fully characterize the glycosidic residues bore by AS-A and to determine its function.

Changes in the distribution of lectin receptors during capacitation and acrosome reaction in boar spermatozoa.

Sperm glycocalyx modifications are known to occur during capacitation and the acrosome reaction (AR). These changes are very important for gamete recognition and fertilization in mammals but are not fully understood. The purpose of this study was to determine the distribution of surface carbohydrates in boar spermatozoa during capacitation and the AR. These processes may be associated with specific changes in the content and distribution of surface carbohydrates. Thirty-nine ejaculates from fertile boars of various breeds were analyzed. N-Acetylglucosamine and sialic acid, mannose and fucose residues were detected by fluorescence microscopy and flow cytometry using FITC-conjugated lectins. Triticum vulgaris agglutinin (WGA) bound on the head and tail of fresh sperm, and fluorescence intensity (FI) decreased in capacitated sperm (6751 to 5621 fluorescence units (FU), P<0.05), and decreased further in acrosome-reacted sperm (5240 FU, P<0.05). Concanavalia ensiformis agglutinin (Con-A) bound homogeneously on the head and the midpiece of fresh sperm with a FI of 5335 FU, and increased in capacitated sperm (5957 FU, P<0.05) mainly on the acrosomal region. In acrosome-reacted sperm, fluorescence was concentrated on the border of the acrosomal region (5608 FU, P<0.05). It was not possible to detect Ulex europaeus agglutinin (UEA) by fluorescence microscopy. However, flow cytometry revealed UEA receptors (187 FU), with a nonsignificant decreased number in capacitated (142 FU) and AR sperm (142 FU). Labeling patterns were similar in all breeds. Sperm glycocalyx modifications observed in this study provide insights to the molecular modifications accompanying capacitation and the AR. This kind of study could improve the diagnosis of reproductive problems of subfertile boars and males of other species.