The pair ceramide 1-phosphate/ceramide kinase regulates intracellular calcium and progesterone-induced human sperm acrosomal exocytosis.

Before fertilization, spermatozoa must undergo calcium-regulated acrosome exocytosis in response to physiological stimuli such as progesterone and zona pellucida. Our laboratory has elucidated the signaling cascades accomplished by different sphingolipids during human sperm acrosomal exocytosis. Recently, we established that ceramide increases intracellular calcium by activating various channels and stimulating the acrosome reaction. However, whether ceramide induces exocytosis on its own, activation of the ceramide kinase/ceramide 1-phosphate (CERK/C1P) pathway or both is still an unsolved issue. Here, we demonstrate that C1P addition induces exocytosis in intact, capacitated human sperm. Real-time imaging in single-cell and calcium measurements in sperm population showed that C1P needs extracellular calcium to induce [Ca2+]i increase. The sphingolipid triggered the cation influx through voltage-operated calcium (VOC) and store-operated calcium (SOC) channels. However, it requires calcium efflux from internal stores through inositol 3-phosphate receptors (IP3R) and ryanodine receptors (RyR) to achieve calcium rise and the acrosome reaction. We report the presence of the CERK in human spermatozoa, the enzyme that catalyzes C1P synthesis. Furthermore, CERK exhibited calcium-stimulated enzymatic activity during the acrosome reaction. Exocytosis assays using a CERK inhibitor demonstrated that ceramide induces acrosomal exocytosis, mainly due to C1P synthesis. Strikingly, progesterone required CERK activity to induce intracellular calcium increase and acrosome exocytosis. This is the first report, implicating the bioactive sphingolipid C1P in the physiological progesterone pathway leading to the sperm acrosome reaction.

Cortisol modulates Ca2+ signaling and acrosome reaction in human sperm.

BACKGROUND: Stress and elevated cortisol levels have negative effects on fertility, although there is controversy about the effect of cortisol on human sperm. One study reported that hydrocortisone (HC), the synthetic form of cortisol, does not activate CatSper channel but is able to inhibit its activation by progesterone (Pg). However, subsequent reports showed that HC has an agonist effect on CatSper, producing intracellular Ca2+ ([Ca2+ ]i ) increases. These studies were performed using only electrophysiological techniques and fluorometric measurements of Ca2+ . Therefore, it is important to evaluate the effects of different HC concentrations on human sperm physiology using other approaches and techniques. OBJECTIVE: To analyze the effects of different HC concentrations on human sperm physiology and to evaluate the association of perceived stress, anxiety and depression with acrosome reaction (AR), and semen quality. MATERIALS AND METHODS: In capacitated human sperm, we tested the effects of HC on [Ca2+ ]i mobilization and AR. Furthermore, the perceived stress and symptoms of anxiety and depression were evaluated with standardized psychometric tests. RESULTS: HC induces a low increase in [Ca2+ ]i compared to Pg response while, at higher concentrations, HC inhibits the Pg-induced Ca2+ response. Also, low concentrations of HC induce AR and when co-incubating it with Pg, the percentages of AR are decreased. Finally, the anxiety symptoms are negatively correlated with Pg induced AR and semen quality. DISCUSSION: HC has an agonist effect on [Ca2+ ]i mobilization and AR. However, our data also suggest that HC may compete for the binding site of Pg. Additionally, the association between anxiety and decreased AR could be explained by high cortisol levels. CONCLUSION: Our data showed that HC interferes with the Pg action. Therefore, the negative correlation between anxiety symptoms and Pg-induced AR is due to the accompanying high cortisol levels of this condition and its competitive action with Pg.

When left does not seem right: epigenetic and bioelectric differences between left- and right-sided breast cancer.

BACKGROUND: During embryogenesis lateral symmetry is broken, giving rise to Left/Right (L/R) breast tissues with distinct identity. L/R-sided breast tumors exhibit consistently-biased incidence, gene expression, and DNA methylation. We postulate that a differential L/R tumor-microenvironment crosstalk generates different tumorigenesis mechanisms. METHODS: We performed in-silico analyses on breast tumors of public datasets, developed xenografted tumors, and conditioned MDA-MB-231 cells with L/R mammary extracts. RESULTS: We found L/R differential DNA methylation involved in embryogenic and neuron-like functions. Focusing on ion-channels, we discovered significant L/R epigenetic and bioelectric differences. Specifically, L-sided cells presented increased methylation of hyperpolarizing ion channel genes and increased Ca2+ concentration and depolarized membrane potential, compared to R-ones. Functional consequences were associated with increased proliferation in left tumors, assessed by KI67 expression and mitotic count. CONCLUSIONS: Our findings reveal considerable L/R asymmetry in cancer processes, and suggest specific L/R epigenetic and bioelectric differences as future targets for cancer therapeutic approaches in the breast and many other paired organs.

Direct activation of the proton channel by albumin leads to human sperm capacitation and sustained release of inflammatory mediators by neutrophils.

Human voltage-gated proton channels (hHv1) extrude protons from cells to compensate for charge and osmotic imbalances due metabolism, normalizing intracellular pH and regulating protein function. Human albumin (Alb), present at various levels throughout the body, regulates oncotic pressure and transports ligands. Here, we report Alb is required to activate hHv1 in sperm and neutrophils. Dose-response studies reveal the concentration of Alb in semen is too low to activate hHv1 in sperm whereas the higher level in uterine fluid yields proton efflux, allowing capacitation, the acrosomal reaction, and oocyte fertilization. Likewise, Alb activation of hHv1 in neutrophils is required to sustain production and release of reactive oxygen species during the immune respiratory burst. One Alb binds to both voltage sensor domains (VSDs) in hHv1, enhancing open probability and increasing proton current. A computational model of the Alb-hHv1 complex, validated by experiments, identifies two sites in Alb domain II that interact with the VSDs, suggesting an electrostatic gating modification mechanism favoring the active "up" sensor conformation. This report shows how sperm are triggered to fertilize, resolving how hHv1 opens at negative membrane potentials in sperm, and describes a role for Alb in physiology that will operate in the many tissues expressing hHv1.

Role of human Hv1 channels in sperm capacitation and white blood cell respiratory burst established by a designed peptide inhibitor.

Using a de novo peptide inhibitor, Corza6 (C6), we demonstrate that the human voltage-gated proton channel (hHv1) is the main pathway for H+ efflux that allows capacitation in sperm and permits sustained reactive oxygen species (ROS) production in white blood cells (WBCs). C6 was identified by a phage-display strategy whereby ∼1 million novel peptides were fabricated on an inhibitor cysteine knot (ICK) scaffold and sorting on purified hHv1 protein. Two C6 peptides bind to each dimeric channel, one on the S3-S4 loop of each voltage sensor domain (VSD). Binding is cooperative with an equilibrium affinity (Kd) of ∼1 nM at -50 mV. As expected for a VSD-directed toxin, C6 inhibits by shifting hHv1 activation to more positive voltages, slowing opening and speeding closure, effects that diminish with membrane depolarization.

Aspectos teóricos sobre planificación de la emergencia en el lugar del accidente: comando del lugar / Theorical aspects on emergency planning in the place of the accident

Regional Symposium on Emergency Preparedness and Chemical Disasters: a Challenge for the XXI Century

Simposio Regional sobre Preparativos para Emergencias y Desastres Químicos: un Reto para el Siglo XXI. Organización Panamericana de la Salud; 30 oct. -1 nov. 1996

Cuidados de enfermería en el recién nacido de bajo peso. factores asociados / Nursing care in the low-birth-weight newborn infants: associated factors

Se realiza el estudio de los 86 nacimientos ocurridos en el Hospital Maternoinfantil "Leopoldito Martínez" de San José de las Lajas" en el período comprendido entre el 1 de julio de 1982 y el 30 de junio de 1983. Se consideró como recién nacido de bajo peso lo propuesto por Batlagia y Lubchenco. Se analizaron un conjunto de factores que estuvieron presentes antes o durante el embarazo de los nacidos bajo peso. Se determinó el estado al nacer y las enfermedades más frecuentes. La mayor frecuencia de Apgar bajo ocurrió en los productos de embarazo con menos de 36 semanas. Las enfermedades más frecuentes en el bajo de peso fueron en orden descendente la hiperbilirrubinemia, la plétora sanguínea, el ictero fisiológico, la hipoglicemia, la sepsis urinaria, el distress respiratorio y la bronconeumonia congénita. Se concluye que es importante por parte del personal de Enfermería que labora en la Sala de neonatología aplicar los cuidados específicos a este recién nacido

Cuidados de enfermería en el recién nacido de bajo peso: factores asociados / Nursing care in the low-birth-weight newborn infants: associated factors

Se realiza el estudio de los 86 nacimientos ocurridos en el Hospital Maternoinfantil "Leopoldito Martínez" de San José de las Lajas" en el período comprendido entre el 1 de julio de 1982 y el 30 de junio de 1983. Se consideró como recién nacido de bajo peso lo propuesto por Batlagia y Lubchenco. Se analizaron un conjunto de factores que estuvieron presentes antes o durante el embarazo de los nacidos bajo peso. Se determinó el estado al nacer y las enfermedades más frecuentes. La mayor frecuencia de Apgar bajo ocurrió en los productos de embarazo con menos de 36 semanas. Las enfermedades más frecuentes en el bajo de peso fueron en orden descendente la hiperbilirrubinemia, la plétora sanguínea, el ictero fisiológico, la hipoglicemia, la sepsis urinaria, el distress respiratorio y la bronconeumonia congénita. Se concluye que es importante por parte del personal de Enfermería que labora en la Sala de neonatología aplicar los cuidados específicos a este recién nacido