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1.
Rev Gastroenterol Mex (Engl Ed) ; 89(1): 121-143, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38580493

RESUMEN

INTRODUCTION: Gastroesophageal reflux disease (GERD) is very prevalent in the general population, with a broad spectrum of clinical manifestations, requiring accurate diagnosis and treatment. AIM: The aim of this expert review is to establish good clinical practice recommendations for the diagnosis and personalized treatment of GERD. METHODS: The good clinical practice recommendations were produced by a group of experts in GERD, members of the Asociación Mexicana de Gastroenterología (AMG), after carrying out an extensive review of the published literature and discussing each recommendation at a face-to-face meeting. This document does not aim to be a clinical practice guideline with the methodology such a document requires. RESULTS: Fifteen experts on GERD formulated 27 good clinical practice recommendations for recognizing the symptoms and complications of GERD, the rational use of diagnostic tests and medical treatment, the identification and management of refractory GERD, the overlap with functional disorders, endoscopic and surgical treatment, and GERD in the pregnant woman, older adult, and the obese patient. CONCLUSIONS: An accurate diagnosis of GERD is currently possible, enabling the prescription of a personalized treatment in patients with this condition. The goal of the good clinical practice recommendations by the group of experts from the AMG presented in this document is to aid both the general practitioner and specialist in the process of accurate diagnosis and treatment, in the patient with GERD.


Asunto(s)
Reflujo Gastroesofágico , Anciano , Femenino , Humanos , Embarazo , Endoscopía , Reflujo Gastroesofágico/diagnóstico , Reflujo Gastroesofágico/terapia
2.
Artículo en Inglés, Español | MEDLINE | ID: mdl-31174905

RESUMEN

INTRODUCTION AND AIMS: Achalasia is characterized by incomplete relaxation of the lower esophageal sphincter and esophageal aperistalsis. The efficacy of peroral endoscopic myotomy (POEM) is similar to that of the Heller myotomy, with an apparently greater prevalence of gastroesophageal reflux disease. Our aim was to determine the presence of GERD in a post-POEM cohort of Mexican patients with achalasia and follow-up of at least 12 months. MATERIALS AND METHODS: A retrospective cohort study was conducted on post-POEM patients with a minimum of 12 months of follow-up, within the time frame of 2012 to 2017. Pregnant patients were excluded. Serial endoscopy, pH study, and GERDQ application were performed. Univariate and bivariate data analyses were carried out and statistical significance was set at a P<0.05. RESULTS: Sixty-eight patients had post-POEM follow-up for 12 months. Of those patients, follow-up continued to 24 months for 58, 36 months for 47, 48 months for 39, and 60 months for 25. Mean patient age was 47.8±14.3 years, 57.3% of the patients were women, 77.9% were treatment-naïve, and 54.4% had type II achalasia. The pH study, endoscopy, and questionnaire were positive in 73, 28, and 18% at 3 months; 48, 35, and 13% at 6 months, and 55, 30, and 15% at 12 months, respectively. Once the proton pump inhibitor was begun, the percentages decreased to 5, 2, and 6% at 24 months; 6, 2, and 8% at 36 months; 4,1, and 6% at 48 months; and 3, 1, and 4% at 60 months, respectively. There was no relation between the efficacy of POEM and the presence or intensity of GERD. There were no secondary complications due to gastroesophageal reflux. CONCLUSIONS: The post-POEM prevalence of GERD was 50% in the short term (12 months), with no evidence of complications at the medium term or long term (60 months). Gastroesophageal reflux was adequately controlled through proton pump inhibitors administration in over 95% of the cases.


Asunto(s)
Acalasia del Esófago/cirugía , Reflujo Gastroesofágico/etiología , Complicaciones Posoperatorias , Piloromiotomia , Adulto , Anciano , Femenino , Estudios de Seguimiento , Reflujo Gastroesofágico/tratamiento farmacológico , Reflujo Gastroesofágico/epidemiología , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/tratamiento farmacológico , Complicaciones Posoperatorias/epidemiología , Prevalencia , Inhibidores de la Bomba de Protones/uso terapéutico , Estudios Retrospectivos , Resultado del Tratamiento
3.
Rev Gastroenterol Mex (Engl Ed) ; 84(3): 372-397, 2019.
Artículo en Inglés, Español | MEDLINE | ID: mdl-31213326

RESUMEN

INTRODUCTION: Non-cardiac chest pain is defined as a clinical syndrome characterized by retrosternal pain similar to that of angina pectoris, but of non-cardiac origin and produced by esophageal, musculoskeletal, pulmonary, or psychiatric diseases. AIM: To present a consensus review based on evidence regarding the definition, epidemiology, pathophysiology, and diagnosis of non-cardiac chest pain, as well as the therapeutic options for those patients. METHODS: Three general coordinators carried out a literature review of all articles published in English and Spanish on the theme and formulated 38 initial statements, dividing them into 3 main categories: (i)definitions, epidemiology, and pathophysiology; (ii)diagnosis, and (iii)treatment. The statements underwent 3rounds of voting, utilizing the Delphi system. The final statements were those that reached >75% agreement, and they were rated utilizing the GRADE system. RESULTS AND CONCLUSIONS: The final consensus included 29 statements. All patients presenting with chest pain should initially be evaluated by a cardiologist. The most common cause of non-cardiac chest pain is gastroesophageal reflux disease. If there are no alarm symptoms, the initial approach should be a therapeutic trial with a proton pump inhibitor for 2-4weeks. If dysphagia or alarm symptoms are present, endoscopy is recommended. High-resolution manometry is the best method for ruling out spastic motor disorders and achalasia and pH monitoring aids in demonstrating abnormal esophageal acid exposure. Treatment should be directed at the pathophysiologic mechanism. It can include proton pump inhibitors, neuromodulators and/or smooth muscle relaxants, psychologic intervention and/or cognitive therapy, and occasionally surgery or endoscopic therapy.


Asunto(s)
Dolor en el Pecho/terapia , Dolor en el Pecho/diagnóstico , Consenso , Humanos , México
4.
Artículo en Inglés, Español | MEDLINE | ID: mdl-29496268

RESUMEN

INTRODUCTION AND AIMS: Achalasia is characterized by the absence of lower esophageal sphincter relaxation and esophageal aperistalsis. Diagnosis is confirmed through high-resolution esophageal manometry. Laparoscopic myotomy is the standard treatment, but peroral endoscopic myotomy (POEM) is a safe and effective alternative, with good short-term and medium-term results. Our aim was to describe the short-term and medium-term experience with POEM at a tertiary care center. MATERIALS AND METHODS: The study was conducted within the time frame of November 2014 and February 2017. Treatment-naïve achalasia patients and previously-treated achalasia patients that were candidates for POEM were included. A protocolized 24-month follow-up was carried out. RESULTS: Fifty procedures were included and 31 (68%) were performed on women. Forty-one (82%) of the procedures were carried out on previously untreated patients, 7 (14%) were performed on previously treated patients, and 2 (4%) of the patients had redo-POEM. The mean age of the patients was 48.8±14.1 years. The pre-POEM Eckardt score was 9 and the integrated relaxation pressure was 24.4mmHg. Sixty-eight percent of the patients had type ii achalasia. Procedure time was 80min and myotomy length was 12.6cm. Hospital stay was 3 days and subcutaneous emphysema was the most common adverse event (30%). A total of 22/50 (44%) patients reached the 24-month follow-up, maintaining the Eckardt score and the decrease in the integrated relaxation pressure. There were no deaths. A total of 47.5% of the patients had a positive pH-study at 6 months, 15% had clinical reflux, and 35% presented with mild esophagitis. All the patients were adequately controlled with proton pump inhibitors. CONCLUSION: POEM is safe and effective in the short term and medium term for the treatment of achalasia and other esophageal motor disorders in Mexican patients.


Asunto(s)
Acalasia del Esófago/cirugía , Trastornos de la Motilidad Esofágica/cirugía , Miotomía/métodos , Cirugía Endoscópica por Orificios Naturales/métodos , Adulto , Anciano , Femenino , Humanos , Masculino , México , Persona de Mediana Edad , Centros de Atención Terciaria , Resultado del Tratamiento
5.
Rev Gastroenterol Mex (Engl Ed) ; 83(2): 168-189, 2018.
Artículo en Inglés, Español | MEDLINE | ID: mdl-29555103

RESUMEN

INTRODUCTION: Significant advances have been made in the knowledge and understanding of the epidemiology, pathophysiology, diagnosis, and treatment of chronic constipation, since the publication of the 2011 guidelines on chronic constipation diagnosis and treatment in Mexico from the Asociación Mexicana de Gastroenterología. AIMS: To present a consensus review of the current state of knowledge about chronic constipation, providing updated information and integrating the new scientific evidence. METHODS: Three general coordinators reviewed the literature published within the time frame of January 2011 and January 2017. From that information, 62 initial statements were formulated and then sent to 12 national experts for their revision. The statements were voted upon, using the Delphi system in 3 voting rounds (2 electronic and one face-to-face). The statements were classified through the GRADE system and those that reached agreement >75% were included in the consensus. RESULTS AND CONCLUSIONS: The present consensus is made up of 42 final statements that provide updated knowledge, supplementing the information that had not been included in the previous guidelines. The strength of recommendation and quality (level) of evidence were established for each statement. The current definitions of chronic constipation, functional constipation, and opioid-induced constipation are given, and diagnostic strategies based on the available diagnostic methods are described. The consensus treatment recommendations were established from evidence on the roles of diet and exercise, fiber, laxatives, new drugs (such as prucalopride, lubiprostone, linaclotide, plecanatide), biofeedback therapy, and surgery.


Asunto(s)
Estreñimiento/diagnóstico , Estreñimiento/terapia , Enfermedad Crónica , Terapia Combinada , Estreñimiento/epidemiología , Técnica Delphi , Humanos , México/epidemiología
7.
Artículo en Español | LILACS | ID: biblio-963942

RESUMEN

El presente trabajo forma parte del plan de beca de maestría "Aportes del psicoanálisis al abordaje de las toxicomanías", enmarcado en el proyecto UBACyT 2014-2017: "Operadores conceptuales de la segunda tópica freudiana: alcances y límites" (Laznik, 2014). Entendiendo que el modo de recortar el objeto de estudio supone ya una toma de posición y un modo de pensar la dirección de la cura, este artículo se propone situar las dificultades que la definición de la noción de toxicomanía presenta para la teoría psicoanalítica.


This article is part of the master plan "Contributions of psychoanalysis to addressing drug addiction ", set in the 2014-2017 UBACyT project: "Conceptual operators of the second Freudian topography: scope and limits" (Laznik, 2014). Understanding that the way in which the object of study is outlined involves taking a stand as well as a particular way of understanding the direction of the treatment, this article intends to place the difficulties that the definition of the concept of addiction presents for psychoanalytic theory.


Asunto(s)
Humanos , Teoría Psicoanalítica , Detección de Abuso de Sustancias , Trastornos Relacionados con Sustancias/diagnóstico
8.
Rev Gastroenterol Mex ; 81(3): 149-67, 2016.
Artículo en Inglés, Español | MEDLINE | ID: mdl-26976238

RESUMEN

BACKGROUND: Since the publication in 2009 of the Guidelines on the Diagnosis and Treatment of Irritable Bowel Syndrome of the Asociación Mexicana de Gastroenterología (2009 Guidelines), there have been significant advances in our knowledge of the epidemiology, pathophysiology, diagnosis, and treatment of this disease. AIMS: To present a consensus review of the most current knowledge of IBS, updating the 2009 Guidelines by incorporating new internationally published scientific evidence, with a special interest in Mexican studies. METHODS: The PubMed literature from January 2009 to March 2015 was reviewed and complemented through a manual search. Articles in English and Spanish were included and preference was given to consensuses, guidelines, systematic reviews, and meta-analyses. Statements referring to the different aspects of the disease were formulated and voted upon by 24 gastroenterologists employing the Delphi method. Once a consensus on each statement was reached, the quality of evidence and strength of recommendation were determined through the GRADE system. RESULTS: Forty-eight statements were formulated, updating the information on IBS and adding the complementary data that did not appear in the 2009 Guidelines regarding the importance of exercise and diet, diagnostic strategies, and current therapy alternatives that were analyzed with more stringent scientific vigor or that emerged within the last 5 years. CONCLUSIONS: We present herein a consensus review of the most relevant advances in the study of IBS, updating and complementing the 2009 Guidelines. Several studies conducted in Mexico were included.


Asunto(s)
Síndrome del Colon Irritable/terapia , Consenso , Técnica Delphi , Medicina Basada en la Evidencia , Guías como Asunto , Humanos , México
9.
Rev Gastroenterol Mex ; 80(2): 121-9, 2015.
Artículo en Inglés, Español | MEDLINE | ID: mdl-26148745

RESUMEN

INTRODUCTION: Non-cardiac chest pain (NCCP) is mainly related to oesophageal disease, and in spite of being a common condition in Mexico, information regarding it is scarce. AIM: To assess the clinical characteristics and health-related quality of life of patients with NCCP of presumed oesophageal origin. MATERIAL AND METHODS: Patients with NCCP of presumed oesophageal origin with no previous treatment were included in the study. Associated symptoms were assessed and upper gastrointestinal endoscopy and 24-hour oesophageal pH monitoring were performed to diagnose gastroesophageal reflux disease, while oesophageal manometry was used to determine oesophageal motility disorders. The SF-36 Health-Related Quality of Life (HR-QoL) questionnaire was completed and its results compared to a control group without oesophageal symptoms. RESULTS: The study included 33 patients, of which 61% were women, and the mean age was 46.1 (±11.6) years. Causes of NCCP were gastroesophageal reflux disease in 48%, achalasia in 34%, and functional chest pain in 18%. The average progression time for chest pain was 24 (2-240) months, with ≤ 3 events/week in 52% of the patients. The most frequent accompanying symptoms were: regurgitation (81%), dysphagia (72%) and heartburn (66%). Patients with NCCP show deterioration in HR-QoL compared to the control group (P=.01), regardless of chest pain aetiology. The most affected areas were general perception of health, emotional issues, and mental health sub-scale (P>0.05). CONCLUSIONS: In our population, patients with NCCP show deterioration in HR-QoL regardless of the aetiology, frequency, and accompanying symptoms.


Asunto(s)
Dolor en el Pecho/etiología , Trastornos de la Motilidad Esofágica/diagnóstico , Reflujo Gastroesofágico/diagnóstico , Calidad de Vida , Adulto , Estudios de Casos y Controles , Trastornos de la Motilidad Esofágica/complicaciones , Monitorización del pH Esofágico , Esofagoscopía , Femenino , Reflujo Gastroesofágico/complicaciones , Indicadores de Salud , Humanos , Masculino , Manometría , México , Persona de Mediana Edad
11.
Rev Gastroenterol Mex ; 77 Suppl 1: 47-9, 2012 Aug.
Artículo en Español | MEDLINE | ID: mdl-22939480
12.
Rev Gastroenterol Mex ; 76(3): 231-6, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-22041312

RESUMEN

INTRODUCTION: Data regarding the age impact on the clinical presentation and esophageal motility in adults with idiopathic achalasia are scarce. OBJECTIVE: To asses the clinical and manometric features of elderly patients with idiopathic achalasia. METHODS: The medical charts of 159 patients diagnosed with achalasia were divided into two groups according to the patients' age: ?60 years (n = 123) and >60 years (n = 36). Clinical and manometric findings [esophageal body aperistalsis, basal lower esophageal sphincter (LES) pressure and abnormal LES relaxation] of both groups were compared upon diagnosis. Patients with previous esophageal interventions were excluded. RESULTS: Only chest pain was more common in the ?60 year-old group (51.2% vs. 22.2%, p <0.003). This difference remained when comparing the group of men ≤60 years. Other presenting features (including sex, weight loss, and presence of dysphagia, regurgitation and heartburn) did not differ between the groups. The LES relaxation was incomplete in 70.4% of the cases. No differences on the basal LES pressure, residual LES pressure or the amplitude of the esophageal body contractions between both groups were found. Considering only the classic achalasia cases, symptomatic time before diagnosis was greater in ≤60 years compared with older patients: 24 vs. 12 months (p <0.05), respectively. CONCLUSIONS: These results suggest that chest pain is more common in younger male achalasia patients and residual LES pressure decreases with age.


Asunto(s)
Acalasia del Esófago/diagnóstico , Acalasia del Esófago/fisiopatología , Manometría , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos
13.
Toxicol In Vitro ; 24(5): 1338-46, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20460147

RESUMEN

One important effect of lead toxicity in erythrocytes consists of increasing [Ca(2+)](i) which in turn may cause alterations in cell shape and volume and it is associated with cellular rigidity, hemolysis, senescence and apoptosis. In this work, we proposed the use of erythrocytes incubated with Pb(2+) to assess association of the mechanisms of lead erythrocyte oxidative damage and calcium homeostasis. Lead incubation produced an increase in [Ca(2+)](i) dose- and time-dependent, which mainly involved Ca(2+) entry mechanism. Additionally, in this in vitro model alterations similar to erythrocytes of lead-exposed workers were produced: Increase in Ca(2+) influx, decrease in (Ca(2+)-Mg(2+))-ATPase activity and GSH/GSGG ratio; increase in lipoperoxidation, protein carbonylation and osmotic fragility accompanied of dramatic morphological changes. Co-incubation with trolox, a soluble vitamin-E analog is able to prevent these alterations indicating that lead damage mechanism is strongly associated with oxidative damage with an intermediate toxic effect via [Ca(2+)](i) increase. Furthermore, erythrocytes oxidation induced with a free radical generator (APPH) showed effects in [Ca(2+)](i) and oxidative damage similar to those found in erythrocytes incubated with lead. Co-incubation with trolox prevents the oxidative effects induced by AAPH in erythrocytes. These results suggest that increase of [Ca(2+)](i) depends on the oxidative status of the erythrocytes incubated with lead. We consider that this model contributes in the understanding of the relation between oxidative damage induced by lead exposure and Ca(2+) homeostasis, the consequences related to these phenomena and the molecular basis of lead toxicity in no excitable cells.


Asunto(s)
Calcio/metabolismo , Eritrocitos/efectos de los fármacos , Plomo/toxicidad , Estrés Oxidativo , Adulto , Relación Dosis-Respuesta a Droga , Eritrocitos/metabolismo , Eritrocitos/patología , Humanos , Espacio Intracelular/metabolismo , Masculino
14.
Rev Gastroenterol Mex ; 75(1): 42-66, 2010.
Artículo en Español | MEDLINE | ID: mdl-20423782

RESUMEN

INTRODUCTION: The goal of a comprehensive treatment in irritable bowel syndrome (IBS) patients should be the improvement of symptoms and improve the quality of life. AIM: To review the drugs recommended in IBS, their mechanisms of action, side effects, risks and benefits, contraindications, availability in our country and the evidence supporting their use. MATERIAL AND METHODS: A technical and narrative review which evaluated the articles published in national and world literature regarding the pharmacological treatment of IBS was performed. PubMed and IMBIOMED electronic databases were searched (until September 2009) using all descriptors regarding IBS and drug therapy. RESULTS: There is enough clinical evidence to recommend the use of antispasmodics (alone orin combination) and tricyclic antidepressants for pain treatment in IBS. Laxatives are useful in the management of chronic constipation, but there is little evidence in the management of IBS. Although, antiflatulents and antidiarrheals are widely used there is little information supporting its use. The use of a nonabsorbable antibiotic (rifaximin) is effective in a subgroup of IBS patients. Serotoninergics drugs have proven effective in relieving symptoms of IBS; however, these drugs require caution in their use. There are studies have shown that probiotics improve some symptoms of IBS. CONCLUSIONS: There are many effective treatment options in the symptomatic management of IBS. The choice of treatment should be based on the predominant symptoms of each patient.


Asunto(s)
Síndrome del Colon Irritable/tratamiento farmacológico , Alprostadil/análogos & derivados , Alprostadil/uso terapéutico , Antibacterianos/uso terapéutico , Antidiarreicos/uso terapéutico , Antiespumantes/uso terapéutico , Humanos , Laxativos/uso terapéutico , Lubiprostona , Parasimpatolíticos/uso terapéutico , Probióticos/uso terapéutico , Psicotrópicos/uso terapéutico , Serotoninérgicos/uso terapéutico
15.
J Chem Phys ; 130(11): 114103, 2009 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-19317527

RESUMEN

The transformation from angle-action variables to Cartesian coordinates is an important step of the semiclassical description of bimolecular collisions and photofragmentations. The basic reason is that dynamical conditions corresponding to molecular beam experiments are ideally generated in angle-action variables, whereas the classical equations of motion are ideally solved in Cartesian coordinates by standard numerical approaches. To our knowledge, this transformation is available in the literature only for atom-diatom arrangements. The goal of the present work is to derive it for diatom-polyatom ones. The analogous transformation for any type of arrangement may then be straightforwardly deduced from that presented here.

16.
Toxicol Appl Pharmacol ; 220(1): 1-8, 2007 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-17292428

RESUMEN

Erythrocytes are the route of lead distribution to organs and tissues. The effect of lead on calcium homeostasis in human erythrocytes and other excitable cells is not known. In the present work we studied the effect of lead intoxication on the uptake and efflux (measured as (Ca(2+)-Mg(2+))-ATPase activity) of calcium were studied in erythrocytes obtained from lead-exposed workers. Blood samples were taken from 15 workers exposed to lead (blood lead concentration 74.4+/-21.9 microg/dl) and 15 non-exposed workers (9.9+/-2 microg/dl). In erythrocytes of lead-exposed workers, the intracellular free calcium was 79+/-13 nM, a significantly higher concentration (ANOVA, P<0.01) than the one detected in control (30+/-9 nM). The enhanced intracellular free calcium was associated with a higher osmotic fragility and with important modifications in erythrocytes shape. The high intracellular free calcium in lead-exposed workers was also related to a 100% increase in calcium incorporation and to 50% reduction of (Ca(2+)-Mg(2+))-ATPase activity. Lipid peroxidation was 1.7-fold higher in erythrocytes of lead-exposed workers as compared with control. The alteration on calcium equilibrium in erythrocytes is discussed in light of the toxicological effects in lead-exposed workers.


Asunto(s)
Calcio/sangre , Eritrocitos/metabolismo , Intoxicación por Plomo/metabolismo , Exposición Profesional , Adulto , ATPasa de Ca(2+) y Mg(2+)/metabolismo , Humanos , Masculino
17.
Phys Chem Chem Phys ; 8(39): 4550-8, 2006 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-17047752

RESUMEN

A full-dimensional quasi-classical trajectories study on the vibrational predissociation (VP) of the Ne79Br2(B) complex is presented. Following the most recent experiments, the Br2(B) vibrational levels v'=16-29 were explored. The total angular momentum, J, was taken to be zero, and a semiclassical Franck-Condon model to compute initial conditions from quantum distributions was employed. Predissociation lifetimes were extracted from Ne79Br2 population decay by using two different exponential laws. Predicted lifetimes are in excellent agreement with the last experimental results [J. A. Cabrera, C. R. Bieler, B. C. Olbricht, W. E. van der Veer and K. C. Janda, J. Chem. Phys., 2005, 123, 054311]. The Br2 fragment ro-vibrational distributions resulting from the VP of the molecule were obtained from the statistics of classical magnitudes using the standard binning procedure. Computed rotational distributions (for the Deltav'=-1, -2 channels) are also in very good agreement with the experimental results [M. Nejad-Sattari and T. A. Stephenson, J. Chem. Phys., 1997, 106 5454]. The influence of two quantum effects-the closing of the Deltav'=-1 dissociation channel and the intramolecular vibrational relaxation (IVR) mechanism-on the agreement with experimental rotational distributions, is discussed. Due to the classical character of our calculations and the binning procedure we used, the agreement of computed vibrational distributions with experimental and quantum theoretical is qualitative. For instance, for v'=28-for which the Deltav'=-1 channel is experimentally found to be closed-the Deltav'=-2 channel becomes statistically more significant. A discussion on the viability of similar quasi-classical methods to model the VP dynamics of analogous clusters is presented.

18.
Dev Biol ; 236(1): 220-9, 2001 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-11456456

RESUMEN

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.


Asunto(s)
Reacción Acrosómica , Canales de Calcio/fisiología , Calcio/metabolismo , Fertilización , Animales , Calcio/farmacología , Canales de Calcio/metabolismo , Relación Dosis-Respuesta a Droga , Ácido Egtácico/farmacología , Electrofisiología , Inhibidores Enzimáticos/farmacología , Concentración de Iones de Hidrógeno , Indoles/farmacología , Masculino , Modelos Biológicos , Níquel/farmacología , Erizos de Mar , Agua de Mar , Tapsigargina/farmacología , Factores de Tiempo
19.
Biochim Biophys Acta ; 1464(2): 188-98, 2000 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-10727606

RESUMEN

When human sperm was incubated in medium deprived of glucose, glucose restoration caused a transient hyperpolarization of the plasma membrane. This hyperpolarization was also induced by fructose but not by 2-deoxyglucose, a substrate that cannot be metabolized. The hyperpolarization was inhibited by NaF, a glycolysis inhibitor, but not by mitochondrial inhibitors (cyanide, rotenone and antimycin), suggesting that it depended on glycolysis. Furthermore, the hyperpolarization was still induced in medium containing a high concentration of KCl and was insensitive to the K(+) channel blocker TEA and the Cl(-) channel blocker niflumic acid, but it was blocked by ouabain. This suggested that upon glucose addition, there was an increase in the concentration of ATP, that in turns increased the Na(+),K(+)-ATPase activity. Since this pump is electrogenic (2K(+)/3Na(+)) the plasma membrane hyperpolarized. On the other hand, CCCP, a proton ionophore, inhibited the hyperpolarization induced by glucose. When CCCP was added to glucose-treated hyperpolarized sperm, it caused a depolarization that triggered a Ca(2+) influx sensitive to nickel, an inhibitor of voltage-dependent calcium channels. Moreover, CCCP caused hyperpolarization in sperm incubated in medium without calcium, a known condition that depolarizes sperm. This indicated that CCCP induced proton permeability in the plasma membrane that was able to change the membrane potential to a value corresponding to the E(H) and that was also able to clamp it, so that it prevented the hyperpolarization induced by glucose.


Asunto(s)
Glucosa/farmacología , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Espermatozoides/enzimología , Benzotiazoles , Carbocianinas , Carbonil Cianuro m-Clorofenil Hidrazona , Membrana Celular/efectos de los fármacos , Colorantes Fluorescentes , Fura-2 , Humanos , Ionóforos , Masculino , Potenciales de la Membrana/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Espermatozoides/efectos de los fármacos
20.
Arch Androl ; 42(2): 119-23, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10101579

RESUMEN

The authors investigated the possible effect of nitric oxide (NO) releasers (the free radical form of nitrogen monoxide, which control some functions of many cells) on rabbit spermatozoa. A significant (P < .01) increment was found in the percentage of the acrosome reaction in rabbit spermatozoa incubated for 30-60 min in presence of the NO releasers sodium nitroprusside (SNP) and N-acetyl-S-nitroso cysteine (NACysSNO), but not with S-nitroso cysteine (CysSNO). This effect was reverted or lowered when the NO scavenger HbO2 was included in the medium. The effects of SNP and NACysSNO on acrosome reaction do not appear to be related to glucose utilization, viability, or lipid peroxidation.


Asunto(s)
Óxido Nítrico/metabolismo , Espermatozoides/metabolismo , Animales , Masculino , Conejos
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