Determinants and impact of alexithymia on quality of life in Parkinson’s disease / Determinantes e impacto de la alexitimia en la calidad de vida en la enfermedad de Parkinson

Introduction: Alexithymia is a neuropsychiatric symptom conceptualized as difficulty iden-tifying and describing feelings. Although associated with other non-motor symptoms, mainlyneuropsychiatric, alexithymia may present as an isolated symptom in persons with Parkinson’sDisease (PwP). The objective of the study is to identify determinants of alexithymia and itsassociation with quality of life (QoL) in Parkinson’s disease. Methods: Subjects with Parkinson’s disease were recruited. The following instruments wereapplied: Movement Disorders Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS),Non-Motor Symptoms Scale (NMSS), Montreal Cognitive Assessment (MoCA), Toronto alexithymiascale (TAS-20) and Parkinson’s Disease Questionnaire (PDQ-8). Matched healthy controls werescreened using TAS-20. Clinical and demographical variables were compared between alex-ithymic and non-alexithymic. Regression models were used to find determinants of alexithymia.Impact of alexithymia on QoL was estimated with a linear regression model.Results: 98 patients were included. 56.1% PwP and 28.8% controls were alexithymic (p < 0.001).Education level (OR 0.86) and NMSS urinary score (OR 1.09) determined alexithymia as well asTAS-20 score. Alexithymia was an independent determinant of QoL. Conclusions: Alexithymia is a prevalent independent non-motor symptom in PwP with impacton QoL. Low education level and urinary symptoms are important determinants of alexithymia.(AU)

Introducción: La alexitimia es un rasgo neuropsiquiátrico conceptualizado como la dificul-tad para identificar y describir sentimientos. Aunque está asociado con otros síntomas nomotores, principalmente neuropsiquiátricos, sigue siendo una característica independiente delas personas con enfermedad de Parkinson (PcP). El objetivo del estudio es identificar losdeterminantes de la alexitimia y su asociación con la calidad de vida en la enfermedad deParkinson. Métodos: Se reclutaron sujetos con enfermedad de Parkinson. Se aplicaron los siguientesinstrumentos: escala unificada de la enfermedad de Parkinson de la Sociedad de Trastornosdel Movimiento (MDS-UPDRS), escala de síntomas no motores (NMSS), evaluación cognitiva deMontreal (MoCA), escala de alexitimia de Toronto (TAS-20) y cuestionario de la enfermedadde Parkinson (PDQ-8). Se incluyeron controles sanos pareados, los cuales se evaluaron usandola TAS-20. Las variables clínicas y demográficas se compararon entre pacientes alexitímicos yno alexitímicos. Se utilizaron modelos de regresión para estimar los predictores de alexitimia.El impacto de este rasgo neuropsiquiátrico en la calidad de vida se estimó con un modelo deregresión lineal. Resultados: Se incluyeron 98 pacientes. El 56,1% de PcP y el 28,8% de los controles fueronalexitímicos (p < 0,001). El nivel educativo (OR 0,86) y la puntuación urinaria del NMSS (OR1,09) determinaron la alexitimia, así como la puntuación del TAS-20. La alexitimia fue undeterminante independiente de calidad de vida. Conclusiones: La alexitimia es un síntoma independiente no motor prevalente con impactoen la calidad de vida. El bajo nivel educativo y los síntomas urinarios son determinantesimportantes de esta condición. (AU)

Determinants and impact of alexithymia on quality of life in Parkinson's disease.

INTRODUCTION: Alexithymia is a neuropsychiatric symptom conceptualized as difficulty identifying and describing feelings. Although associated with other non-motor symptoms, mainly neuropsychiatric, alexithymia may present as an isolated symptom in persons with Parkinson's Disease (PwP). The objective of the study is to identify determinants of alexithymia and its association with quality of life (QoL) in Parkinson's disease. METHODS: Subjects with Parkinson's disease were recruited. The following instruments were applied: Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Non-Motor Symptoms Scale (NMSS), Montreal Cognitive Assessment (MoCA), Toronto alexithymia scale (TAS-20) and Parkinson's Disease Questionnaire (PDQ-8). Matched healthy controls were screened using TAS-20. Clinical and demographical variables were compared between alexithymic and non-alexithymic. Regression models were used to find determinants of alexithymia. Impact of alexithymia on QoL was estimated with a linear regression model. RESULTS: 98 patients were included. 56.1% PwP and 28.8% controls were alexithymic (p<0.001). Education level (OR 0.86) and NMSS urinary score (OR 1.09) determined alexithymia as well as TAS-20 score. Alexithymia was an independent determinant of QoL. CONCLUSIONS: Alexithymia is a prevalent independent non-motor symptom in PwP with impact on QoL. Low education level and urinary symptoms are important determinants of alexithymia.

Determinants and impact of alexithymia on quality of life in Parkinson's disease.

INTRODUCTION: Alexithymia is a neuropsychiatric symptom conceptualized as difficulty identifying and describing feelings. Although associated with other non-motor symptoms, mainly neuropsychiatric, alexithymia may present as an isolated symptom in persons with Parkinson's Disease (PwP). The objective of the study is to identify determinants of alexithymia and its association with quality of life (QoL) in Parkinson's disease. METHODS: Subjects with Parkinson's disease were recruited. The following instruments were applied: Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Non-Motor Symptoms Scale (NMSS), Montreal Cognitive Assessment (MoCA), Toronto alexithymia scale (TAS-20) and Parkinson's Disease Questionnaire (PDQ-8). Matched healthy controls were screened using TAS-20. Clinical and demographical variables were compared between alexithymic and non-alexithymic. Regression models were used to find determinants of alexithymia. Impact of alexithymia on QoL was estimated with a linear regression model. RESULTS: 98 patients were included. 56.1% PwP and 28.8% controls were alexithymic (p<0.001). Education level (OR 0.86) and NMSS urinary score (OR 1.09) determined alexithymia as well as TAS-20 score. Alexithymia was an independent determinant of QoL. CONCLUSIONS: Alexithymia is a prevalent independent non-motor symptom in PwP with impact on QoL. Low education level and urinary symptoms are important determinants of alexithymia.

[Analysis of the absorcion's factors of irrigating fluid during transurethral resection of the prostate]. / Análisis de los factores de reabsorción de líquido de irrigación durante la RTU de próstata.

OBJECTIVES: In this study it was our intention to evaluate the relation between the reabsorption of irrigating fluid and three variables: time of the intervention, volume of solution of glicina employee and weight of the fragments, during the RTU of prostate fulfilled to low hydraulic pressure. MATERIAL AND METHOD: We study 74 patients that RTU of prostate was performed with suprapúbica derivation with Amplatz's pod 30 ch. The ethanol was monitored in expired air every 15 minutes during the intervention. Likewise we annotated the time of the intervention, the volume of glicina used and the weight of the fragments extracted. Statistically Anova's text was in use for comparison of averages. RESULTS: 13,6% of the patients absorbed irrigating fluid in some quantity. The range of absorption belongs to 100 cc until 2.000 cc. We did not find a statistically significant difference in the averages of time of resection, volume of glicina and weight of the fragments between the group of patients that had absortion of irrigating fluid and they that didn't had. CONCLUSIONS: Our data show that the operative time, the volume of irrigating fluid and the weight of the resected fragments do not influence the reabsorption of liquid of irrigation when a RTU is realized to low hydraulic pressure.

Análisis de los factores de reabsorción de líquido de irrigación durante la RTU de próstata / Analysis of the absorcion´s factors of irrigating fluid during transurethral resection of the prostate

Objetivos: En este estudio fue nuestra intención evaluar la relación entre la reabsorción de líquido de irrigación y tres variables: tiempo de la intervención, volumen de solución de glicina empleado y peso de los fragmentos, durante la RTU de próstata realizada a baja presión hidráulica. Material y método: Estudiamos 74 pacientes a los que se realizó RTU de próstata con derivación suprapúbica con vaina de Amplatz 30 ch. Se monitorizó el etanol en aire expirado cada 15 minutos durante la intervención. Así mismo se anotaron el tiempo de la intervención, el volumen de glicina utilizado y el peso de los fragmentos extraídos. Estadísticamente se utilizó el Test de Anova para comparación de medias. Resultados: Un 13,6 % de los pacientes absorbieron líquido de irrigación en alguna cantidad. El rango de absorción es de 100 cc hasta 2.000 cc. No se encontró una diferencia estadísticamente significativa entre las medias del tiempo de resección, del volumen de glicina y del peso de los fragmentos entre el grupo de pacientes que había reabsorbido líquido de irrigación y los que no reabsorbieron. Conclusiones: Nuestro estudio pone de manifiesto que el tiempo operatorio, el volumen de líquido de irrigación y el peso de los fragmentos resecados no influyen en la reabsorción de líquido de irrigación cuando se realiza una RTU a baja presión hidráulica (AU)

Objetives: In this study it was our intention to evaluate the relation between the reabsorption of irrigating fluid and three variables: time of the intervention, volume of solution of glicina employee and weight of the fragments, during the RTU of prostate fulfilled to low hydraulic pressure. Material and method: We Study 74 patients that RTU of prostate was performed with suprapúbica derivation with Amplatz’s pod 30 ch. The ethanol was monitored in expired air every 15 minutes during the intervention. Likewise we annotated the time of the intervention, the volume of glicina used and the weight of the fragments extracted. Statistically Anova’s text was in use for comparison of averages. Results: 13,6 % of the patients absorbed irrigating fluid in some quantity. The range of absorption belongs to 100 cc until 2.000 cc. We did not find a statistically significant difference in the averages of time of resection, volume of glicina and weight of the fragments between the group of patients that had absortion of irrigating fluid and they that didn´t had. Conclusions: Our data show that the operative time, the volume of irrigating fluid and the weight of the resected fragments do not influence the reabsorption of liquid of irrigation when a RTU is realized to low hydraulic pressure (AU)

[Quality analysis of the statistical used resources (material and methods section) in thesis projects of a university department]. / Análisis de calidad de los recursos estadísticos (sección material y método) en los proyectos de tesis de un departamento universitario.

INTRODUCTION AND OBJECTIVES: Studies about quality in thesis and investigation projects in biomedical sciences are unusual, but very important in university teaching because is necessary to improve the quality elaboration of the thesis. The objectives the study were to determine the project's quality of thesis in our department, according to the fulfillment of the scientific methodology and to establish, if it exists, a relation between the global quality of the project and the statistical used resources. MATERIAL AND METHODS: Descriptive study of 273 thesis projects performed between 1995-2002 in surgery department of the Zaragoza University. The review realized for 15 observers that they analyzed 28 indicators of every project. Giving a value to each of the indicators, the projects qualified in a scale from 1 to 10 according to the quality in the fulfillment of the scientific methodology. RESULTS: The mean of the project's quality was 5.53 (D.E: 1.77). In 13.9% the thesis projects was concluded with the reading of the work. The three indicators of statistical used resources had a significant difference with the value of the quality projects. DISCUSSION: The quality of the statistical resources is very important when a project of thesis wants to be realized by good methodology, because it assures to come to certain conclusions. In our study we have thought that more of the third part of the variability in the quality of the project of thesis explains for three statistical above-mentioned articles.

Análisis de calidad de los recursos estadísticos (sección material y método) en los proyectos de tesis de un departamento universitario / Quality analysis of the statistical used resources (material and methods section) in thesis projects of a universitary department

INTRODUCCIÓN Y OBJETIVOS: Los estudios sobre la calidad de tesis y proyectos de investigación en ciencias biomédicas son muy escasos, pero de enorme interés para la docencia universitaria, por la necesidad académica de mejorar la calidad del proceso de elaboración de la tesis. Los objetivos del estudio fueron determinar la calidad de los proyectos de tesis de nuestro departamento, según el cumplimiento de la metodología científica y establecer, si existe, una relación entre la calidad global del proyecto y los recursos estadísticos utilizados. MATERIAL Y MÉTODO: Estudio descriptivo en el que se analizaron 273 proyectos de tesis realizados entre 1995 y 2002 en el departamento de Cirugía de la Universidad de Zaragoza. La revisión se realizó por 15 observadores que analizaron 28 indicadores de cada proyecto. Dando un valor ponderado a cada uno de los indicadores, se calificaron los proyectos en una escala de 0 a 10 según la calidad en el cumplimiento de la metodología científica. RESULTADOS: La media de las calificaciones de los proyectos fue de 5,53 (D.E: 1,77.) Un 13,9% de los proyectos de tesis se concluyeron con la defensa y lectura del trabajo. En los tres indicadores de recursos estadísticos se encontró una diferencia estadísticamente significativa con la valoración de la calidad de los proyectos. DISCUSIÓN: La calidad de los recursos estadísticos es de suma importancia cuando se quiere realizar un proyecto de tesis con buena metodología, ya que asegura llegar a conclusiones ciertas. En nuestro estudio hemos encontrado que más de la tercera parte de la variabilidad en la calidad del proyecto de tesis se explica por los tres ítems estadísticos referidos

INTRODUCTION AND OBJETIVES: Studies about quality in thesis and investigation projects in biomedical sciences are unusual, but very important in university teaching because is necessary to improve the quality elaboration of the thesis. The objectives the study were to determine the project's quality of thesis in our department, according to the fulfillment of the scientific methodology and to establish, if it exists, a relation between the global quality of the project and the statistical used resources. MATERIAL AND METHODS: Descriptive study of 273 thesis projects performed between 1995-2002 in surgery department of the Zaragoza University. The review realized for 15 observers that they analyzed 28 indicators of every project. Giving a value to each of the indicators, the projects qualified in a scale from 1 to 10 according to the quality in the fulfillment of the scientific methodology. RESULTS: The mean of the project´s quality was 5.53 (D.E: 1.77). In 13.9% the thesis projects was concluded with the reading of the work. The three indicators of stadistical used resources had a significal difference with the value of the quality projects. DISCUSSION: The quality of the statistical resources is very important when a project of thesis wants to be realized by good methodology, because it assures to come to certain conclusions. In our study we have thought that more of the third part of the variability in the quality of the project of thesis explains for three statistical above-mentioned articles

[Modified technique for transurethral resection of the prostate with suprapubic drainage and local anesthesia]. / Técnica modificada para la resección transuretral de próstata con drenaje suprapúbico y anestesia local.

PURPOSE: To establish a technique for transurethral resection of the prostate (TURP), combining the use of local anaesthesia with an Amplatz suprapubic tube, in patients at high surgical risk. MATERIALS AND METHOD: A study was carried out in 32 patients who underwent TURP with a 30 F Amplatz suprapubic tube following local anaesthesia. This technique was indicated where surgery presented a general risk, in elderly patients, and for patients refusing to undergo spinal intradural or general anaesthesia. The mean age of the patients was 70 years (61-82 years). The risk of surgery was assessed according to the ASA classification. RESULTS: According to the ASA classification, 7 patients were ASA III (21.9%), and 25 patients were ASA IV (78.1%). In 31 of the 32 patients the operation was completed in one session. When questioned about the pain they felt, 11 patients reported no pain, 12 slight discomfort and 3 occasional pain. In the latter three patients, intravenous sedation was enhanced with 0.1 mg etomidate per kg body weight. The volume of the resected fragments ranged from 18 to 120 ml, with a mean of 47 ml, except in one patient with 205 ml who required two treatment sessions. CONCLUSIONS: Large prostate resection in patients at high surgical risk was performed comfortably using a combination of local anaesthesia and an Amplatz suprapubic tube. This procedure is one possible option to be considered as an alternative to other treatments.

Técnica modificada para la resección trnsuretral de próstata con drenaje suprapúbico y anestesia local / Modified technique for transurethral prostatic resection using a suprapubic tube and local anaesthesia

INTRODUCCIÓN: Describimos una técnica para la resección transuretral (RTU) de próstata combinando el uso de anestesia local con un tubo de Amplatz suprapúbico en pacientes con alto riesgo quirúrgico. MATERIAL Y MÉTODOS: Nuestro estudio comprende 32 pacientes sometidos a RTU de próstata con un tubo de Amplatz suprapúbico de 30 Fr bajo anestesia local. Esta técnica se indicó en aquellos casos con alto riesgo quirúrgico. La edad media fue de 70 años (61-82 años). Evaluamos el riesgo quirúrgico de acuerdo a la clasificación ASA.RESULTADOS: De acuerdo con la clasificación ASA del riesgo quirúrgico, se agrupó a los pacientes en los siguientes grupos: 7 pacientes (21,9 por ciento) presentaban ASA III y 25 pacientes (78,1 por ciento) ASA IV. En 31 de 32 pacientes la cirugía se completó en una sesión. Interrogados acerca del dolor percibido, 11 pacientes refirieron no haber sentido dolor, 12 pacientes refirieron una molestia leve, y 3 pacientes un dolor esporádico. En los últimos tres pacientes se incrementó la dosis de sedación intravenosa con 0,1 mg/kg de peso corporal de Etomidato. El volumen medio de los fragmentos resecados fue de 47 ml, con un rango ente 18 y 120 ml, excepto en un paciente con un volumen de 205 ml que precisó dos sesiones quirúrgicas. CONCLUSIONES: La resección de próstatas de gran volumen en pacientes con riesgo quirúrgico se puede realizar con un mínimo de confort para el paciente utilizando una combinación de anestesia local y tubo de Amplatz suprapúbico. Este procedimiento es una opción a tener en cuenta como tratamiento alternativo a otros métodos (AU)

PURPOSE: To establish a technique for transurethral resection of the prostate (TURP), combining the use of local anaesthesia with an Amplatz suprapubic tube, in patients at high surgical risk. MATERIALS AND METHOD: A study was carried out in 32 patients who underwent TURP with a 30 F Amplatz suprapubic tube following local anaesthesia. This technique was indicated where surgery presented a general risk, in ederly patients, and for patients refusing to undergo spinal intradural or general anaesthesia. The mean age of the patients was 70 years (61-82 years). The risk of surgery was assessed according to the ASA classification. RESULTS: According to the ASA classification, 7 patients were ASA III (21,9%), and 25 patients were ASA IV (78,1%). In 31 of the 32 patients the operation was completed in one session. When questioned about the pain they felt, 11 patients reported no pain, 12 slight discomfort and 3 ocassional pain. In the latter three patients, intravenous sedation was enhanced with 0,1 mg etomidate per kg body weight. The volume of the resected fragments ranged from 18 to 120 ml, with a mean of 47 ml, except in one patient with 205 ml who required two treatment sessions. CONCLUSIONS: Large prostate resection in patients at high surgical risk was performed comfortably using a combination of local anaesthesia and an Amplatz suprapubic tube. This procedure is one possible option to be considered as an alternative to other treatments (AU)

A sustained increase in intracellular Ca(2+) is required for the acrosome reaction in sea urchin sperm.

The acrosome reaction (AR), necessary for fertilization in many species, requires an increase in intracellular Ca(2+) ([Ca(2+)](i)). In sea urchin sperm, the AR is triggered by an egg-jelly factor: the associated [Ca(2+)](i) elevation lasts minutes and involves two Ca(2+) permeable channels. Both the opening of the second channel and the onset of the AR occur approximately 5 s after treatment with egg factor, suggesting that these events are linked. In agreement, removal of Ca(2+) from sea water or addition of Ca(2+) channel blockers at the time when opening of the second channel is first detected inhibits AR and causes a "rapid" (t(1/2) = 3--15 s) decrease in [Ca(2+)](i) and partial inhibition of the intracellular pH change associated with the AR. Simultaneous addition of NH(4)Cl and either EGTA, Co(2+), or Ni(2+) 5 s after egg factor prevents the partial inhibition of the evoked pH(i) change observed but does not reverse AR inhibition. Therefore, the sustained increase in [Ca(2+)](i) caused by the second Ca(2+) channel is needed for the sperm AR. Experiments with agents that induce capacitative Ca(2+) uptake (thapsigargin and cyclopiazonic acid) suggest that the second channel opened during the AR could be a store-operated Ca(2+) channel.

Acrosome reaction inactivation in sea urchin sperm.

Acrosome reaction inactivation (ARI) is a process that renders sperm irreversibly refractory to the egg jelly (the natural inducer of the acrosome reaction, AR). This process triggered by the egg jelly, is associated with an increase in [Ca2+]i. However, we show here that a rise in [Ca2+]i alone is not sufficient to induce ARI, since artificially increasing [Ca2+]i with either an ionophore or rising external pH, does not trigger ARI. Contrary to the AR which strictly requires Ca2+, ARI can be triggered almost equally well by Sr2+. On the other hand, Mn2+ inhibits ARI and, as we showed earlier, does not affect AR. These observations indicate that the mechanisms involved in ARI differ from those leading to AR. In addition, we report here that high external pH (a non-physiological inducer of AR) triggers the AR in previously inactivated sperm by opening the same Ca2+ channels activated by the egg jelly. Considering that the opening of Ca2+ channels is one of the earliest responses triggered by the egg jelly and that ARI requires the egg jelly receptor to be activated, we have concluded that ARI involves the uncoupling between the egg jelly receptor and Ca2+ channels. Furthermore, intracellular pH (pHi) determinations, in the presence or absence of ionomycin to substitute for the uncoupled Ca2+ channels, indicate that pHi regulation is also impaired in inactivated sperm. In conclusion, ARI is a manifestation of the uncoupling of the egg jelly receptor from the different ion transport systems required for the acrosome reaction.

Inositol triphosphate receptors in sea urchin sperm.

Inositol 1,4,5-triphosphate (Ins(1,4,5)P3) is a second messenger that regulates Ca2+ channels in many important cell signalling pathways. In sea urchin sperm the outer investment of the egg triggers the acrosome reaction (AR) that involves Ins(1,4,5)P3 production and the opening of two Ca2+ channels. Here we have sought to identify a high-affinity Ins(1,4,5)P3 receptor in Strongylocentrotus purpuratus sperm. An Ins(1,4,5)P3 binding component was affinity-purified 12-fold from sperm extracts. It displayed similar characteristics to the Ins(1,4,5)P3 receptor from other sources: pH-dependent high affinity for Ins(1,4,5)P3 (KD = 261 nM), a tau1/2 of association and dissociation of 50 and 40 s, respectively, specificity (IC50 > 5 microM for Ins(1)P1, Ins(1,4)P2 and Ins(1,3,4,5)P4), and pharmacological sensitivity (10 and 100 microg heparin/ml inhibited 75% and 100% binding respectively). An antibody against the carboxy-terminal of the type I Ins(1,4,5)P3 receptor of somatic cells recognised a plasma membrane component in the sperm head and less intensely in the flagella. This antibody also recognised a 240 kDa band from isolated head plasma membranes, and weakly in flagellar membrane. This IP3 receptor-like protein may mediate the sustained uptake of Ca2+ through the second Ca2+ channel opened during the AR.

Membrane potential regulates sea urchin sperm adenylylcyclase.

Adenylylcyclase (AC) from sea urchin sperm does not appear to be regulated by G proteins [Hildebrandt, J. D., Tash, J. S., Kirchick, H. J., Lipschunits, L., Secra, R. D., & Birmbaumer, L. (1985) Endocrinology 116, 1357-1366]. During sperm activation and the acrosome reaction, membrane potential changes and cAMP increases. Here we explore if membrane potential can modulate the sperm AC. Hyperpolarization of Lytechinus pictus sea urchin sperm either with valinomycin in artificial sea water (ASW) without K+ or with dilution in ASW without Na+ increased the [c-AMP] (2.2- and 5.8-fold, respectively). This increase also occurred in the absence of extracellular Ca2+ (1.9- and 3.1-fold, respectively) and was enhanced by 100 microM IBMX, a phosphodiesterase inhibitor. It has been suggested that sea urchin sperm AC is stimulated by increases in intracellular Ca2+ and intracellular pH. In ASW without Na+ and Ca2+ (0Na0CaASW), sea urchin sperm intracellular pH decreases, and intracellular Ca2+ cannot increase. Therefore, these observations taken together indicate that AC in these cells in modulated by membrane potential. Dilution of Strogylocentrotus purpuratus sperm in 0Na0CaASW hyperpolarized them and increased their cAMP levels (1.3-fold). This stimulation was enhanced by IBMX (1.6-fold). Addition of the egg peptide speract under this condition further hyperpolarized S. purpuratus sperm and synergistically increased [cAMP] above 0Na0CaASW. This stimulation became larger in the presence of IBMX (from 1.6- to 5.2-fold). Since speract cannot elevate intracellular pH or [Ca2+] in 0Na0CaASW, the increase in [cAMP] it causes must be due to sperm hyperpolarization.

A cAMP regulated K+-selective channel from the sea urchin sperm plasma membrane.

Ion channels are deeply involved in sperm physiology. In sea urchin sperm cyclic nucleotide levels increase during quimotaxis and in the acrosome reaction (AR). Although cyclic nucleotides are second messengers known to directly or indirectly modulate ion channels, it is not clear how they modulate sperm responses to the egg outer layer. Here, we describe a cAMP regulated K+-selective channel from sea urchin sperm plasma membranes fused into planar bilayers that may have a role during sea urchin sperm quimotaxis and/or the AR. Its single channel conductance in 100 mM KCl is 103 pS. In bi-ionic experiments, the channel displayed a K+/Na+ permeability ratio (PK+/PNa+) of approximately 5. Thus, in sea water its reversal potential would be approximately -13 mV and channel opening would depolarize spermatozoa. The channel has low open probability (Po = 0.8 +/- 0.2% at 0 mV applied voltage) and weak voltage dependence. Channel activity is reversibly up-regulated by cAMP in the cis bilayer side, but not by cGMP. This modulation followed a single Langmuir isotherm with an apparent kd of 200 microM. At this concentration the channel open probability at 0 mV increased up to 11- fold. TEA+ blocked the channel only from the trans side. Also Ba2+ in trans blocked the channel in a voltage-dependent manner.

Ion channels from the mouse sperm plasma membrane in planar lipid bilayers.

Fusion of purified mouse sperm plasma membranes to planar lipid bilayers resulted in the insertion of three ion channel types. They could be discerned on the basis of their selectivity, conductance, gating and voltage-dependent properties. The presence of a previously reported large, Ca2+ -selective channel was confirmed. Here, it is reported that the Ca2+ -selective channel from mouse sperm plasma membrane displayed a PNa+/PK+ = 1.6 +/- 0.2 (n = 4) and was blocked by micromolar concentrations of ruthenium red. Fusion yielded also a cation-selective channel (PNa+/PK+ = 2.5 +/- 0.3, n = 3) with a main open conductance substate of 103 pS and a smaller open substate of 51 pS (600 mM K+ cis/100 mM Na+ trans). The channel inserted into bilayers in two stable fashions: a high-activity mode (open probability = 0.57 +/- 0.02, n = 3), and a low activity mode (open probability < 1%, n = 4). In high mode, the channel displayed bursting kinetics and burst length was voltage independent. In addition, a perfectly anion-selective channel, with a slope conductance of 83 pS (600 KCl cis/100 KCl trans), was identified. It displayed a high, nearly constant open probability (approximately 0.90) in the 0 to -80 mV range.

Ionic bases of the membrane potential and intracellular pH changes induced by speract in swollen sea urchin sperm.

Signal transduction initiated by the egg peptide, speract, in sea urchin sperm is not fully understood. Hypotonically swollen sperm are a suitable model to study peptide signal transduction. Ion substitution experiments now indicate (i) that the permeability to Na+, Ca2+, and Mg2+ contributes to the sperm resting membrane potential; (ii) the repolarization induced by nM concentrations of speract is Na+ dependent and mediated by an as yet unidentified channel; (iii) the depolarization triggered by nM concentrations of speract involves Ca2+ channels since it is Ca(2+)-dependent and blocked by Co2+ and Ni2+, two Ca2+ channel blockers; (iv) hyperpolarizing swollen sperm with valinomycin increases intracellular pH (pHi) in the same way as speract, thus the speract-induced hyperpolarization may be responsible for the pHi increase.

[Equity and health: research needs for the development of a social policy]. / Equidad y salud: necesidades de investigación para la formulación de una política social.

This article presents a general view of the evolution of the conceptual approach to equity in health and its current meaning. The analysis of equity from the standpoint of distribution-accesibility, use and outcome of health services is proposed. Every point of view is addressed to an operational and policy-making position. This paper concludes with a proposal of perspectives for research development in this field.