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1.
Ultrasound Obstet Gynecol ; 56(6): 921-927, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-31975450

RESUMEN

OBJECTIVES: To evaluate the association between pelvic floor dimensions in nulliparous women at term and fetal head engagement, as assessed by transperineal ultrasound. METHODS: This was a prospective observational study of nulliparous women at term. Before the onset of labor, transperineal ultrasound was used to measure the anteroposterior diameter (APD) of the levator hiatus and the angle of progression (AoP) at rest, on maximum pelvic floor muscle contraction and on maximum Valsalva maneuver (before and after visual feedback). We assessed the correlation between pelvic floor static and dynamic dimensions (levator hiatal APD and levator ani muscle coactivation) and AoP, which is an objective index of fetal head engagement. RESULTS: In total, 282 women were included in the analysis. Among these, 211 (74.8%) women had a vaginal delivery while 71 (25.2%) had a Cesarean delivery. AoP was narrower in the Cesarean-delivery group at rest, on maximum pelvic floor muscle contraction and on maximum Valsalva, whereas no differences in levator hiatal APD were found between the two groups. We found a negative correlation between levator hiatal APD at rest, on maximum pelvic floor muscle contraction and on maximum Valsalva and the duration of the second stage of labor. There was a positive correlation between AoP and levator hiatal APD on maximum Valsalva maneuver after visual feedback (r = 0.15, P = 0.01). Women with levator ani muscle contraction on Valsalva maneuver (i.e. coactivation), both pre and post visual feedback, had a narrower AoP at rest and on maximum Valsalva. After visual feedback, women with levator ani muscle coactivation had a longer second stage of labor than did those without (80.8 ± 61.4 min vs 62.9 ± 43.4 min (P = 0.04)). CONCLUSIONS: Smaller pelvic floor dimensions and levator ani muscle coactivation are associated with higher fetal head station and with a longer second stage of labor in nulliparous women at term. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.


Asunto(s)
Feto/diagnóstico por imagen , Cabeza/embriología , Trabajo de Parto/fisiología , Diafragma Pélvico/fisiología , Ultrasonografía Prenatal/métodos , Adulto , Cesárea/estadística & datos numéricos , Parto Obstétrico/estadística & datos numéricos , Femenino , Humanos , Segundo Periodo del Trabajo de Parto/fisiología , Contracción Muscular/fisiología , Paridad , Diafragma Pélvico/diagnóstico por imagen , Perineo/diagnóstico por imagen , Embarazo , Estudios Prospectivos , Maniobra de Valsalva/fisiología , Adulto Joven
2.
J Fish Biol ; 84(3): 844-63, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24673646

RESUMEN

Observations of the Magadi tilapia Alcolapia grahami in hot, highly alkaline Lake Magadi revealed that they air breathe not only during hypoxia, as described previously, but also during normoxia and hyperoxia. Air breathing under these latter conditions occurred within distinct groupings of fish (pods) and involved only a small proportion of the population. Air breathing properties (duration and frequency) were quantified from video footage. Air breathing within the population followed a diel pattern with the maximum extent of pod formation occurring in early afternoon. High levels of reactive oxygen species (ROS) in the water may be an irritant that encourages the air-breathing behaviour. The diel pattern of air breathing in the field and in experiments followed the diel pattern of ROS concentrations in the water which are amongst the highest reported in the literature (maximum daytime values of 2.53 ­ 8.10 µM H2O2). Interlamellar cell masses (ILCM) occurred between the gill lamellae of fish from the lagoon with highest ROS and highest oxygen levels, while fish from a normoxic lagoon with one third the ROS had little or no ILCM. This is the first record of air breathing in a facultative air-breathing fish in hyperoxic conditions and the first record of an ILCM in a cichlid species.


Asunto(s)
Hiperoxia , Especies Reactivas de Oxígeno/análisis , Respiración , Luz Solar , Tilapia/fisiología , Aire , Animales , Branquias/anatomía & histología , Oxígeno/análisis , Temperatura , Tilapia/anatomía & histología , Agua/química
3.
Eur Rev Med Pharmacol Sci ; 26(6): 1876-1884, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35363336

RESUMEN

OBJECTIVE: Lateral ankle sprains are very common injuries that can be treated with different strategies. The aim of the present systematic review was to provide a comprehensive analysis on the treatment of acute lateral ankle sprains to clarify the possible differences in outcome between surgical and conservative management, different external supports, and different rehabilitation protocols. MATERIALS AND METHODS: A literature search on three different topics was carried out on PubMed, Scopus, and Web of Science databases on June 25th, 2021. The main objective of the literature search was to identify the randomized trials comparing: (1) surgery to conservative management, (2) different external supports, and (3) different rehabilitation protocols for the treatment of acute lateral ankle sprains. Two investigators extracted independently relevant data from each paper and assessed the quality of the trials using the Cochrane Risk of Bias Assessment. RESULTS: A total of 12 studies for the first topic, 8 for the second one and 4 for the last one were included in this review. 8 out of 12 RCTs demonstrated a superior outcome and better socio-economic impact of conservative treatment compared to surgical management. In the other two comparisons, due to the wide variety of braces used and the different rehabilitation protocols, inconclusive results were obtained. CONCLUSIONS: Conservative treatment should be the first choice for severe acute lateral ankle sprains, as it provides satisfactory functional outcomes without the risks and costs of surgery. It was not possible to identify the best external support, but a preference toward flexible braces emerged since they allow an earlier return to daily activities. The paucity of studies comparing different rehabilitation protocols precluded the possibility of defining the ideal one.


Asunto(s)
Traumatismos del Tobillo , Enfermedad Injerto contra Huésped , Esguinces y Distensiones , Traumatismos del Tobillo/terapia , Tratamiento Conservador , Humanos , Esguinces y Distensiones/terapia
4.
Eur Rev Med Pharmacol Sci ; 25(8): 3325-3337, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33928620

RESUMEN

Since the reports in Wuhan (China), in December 2019, of the first cluster of cases of pneumonia caused by the new Coronavirus called 2019-nCoV or SARS-CoV-2, there has been a pandemic spread of the infection. By now, we have no specific therapy to counteract this emergency. The latest epidemiological data suggest that children are just as likely as adults to get infected by the virus. Most of them show mild clinical pictures or are completely asymptomatic, but there is an increased risk for severe disease in infancy (<12 months of age) and in children with underlying medical conditions. In this article, research achievements on the treatment of pediatric SARS-CoV-2 infection are examined.


Asunto(s)
Antivirales/uso terapéutico , COVID-19/terapia , Factores Inmunológicos/uso terapéutico , Adenosina Monofosfato/análogos & derivados , Adenosina Monofosfato/uso terapéutico , Adolescente , Factores de Edad , Alanina/análogos & derivados , Alanina/uso terapéutico , Anticuerpos Monoclonales Humanizados/uso terapéutico , Anticoagulantes/uso terapéutico , Portador Sano , Niño , Preescolar , Cloroquina/uso terapéutico , Terapia de Reemplazo Renal Continuo , Combinación de Medicamentos , Oxigenación por Membrana Extracorpórea , Glucocorticoides/uso terapéutico , Humanos , Hidroxicloroquina/uso terapéutico , Inmunización Pasiva , Inmunoglobulinas Intravenosas/uso terapéutico , Lactante , Recién Nacido , Interferón-alfa/uso terapéutico , Lopinavir/uso terapéutico , Oseltamivir/uso terapéutico , Receptores de Superficie Celular/uso terapéutico , Respiración Artificial , Ribavirina/uso terapéutico , Ritonavir/uso terapéutico , SARS-CoV-2 , Índice de Severidad de la Enfermedad , Trombosis/prevención & control , Tratamiento Farmacológico de COVID-19 , Sueroterapia para COVID-19
5.
Sci Rep ; 11(1): 5119, 2021 03 04.
Artículo en Inglés | MEDLINE | ID: mdl-33664428

RESUMEN

Industrial development and increased energy requirements have led to high consumption of fossil fuels. Thus, environmental pollution has become a profound problem. Every year, a large amount of agro-industrial, municipal and forest residues are treated as waste, but they can be recovered and used to produce thermal and electrical energy through biological or thermochemical conversion processes. Among the main types of agro-industrial waste, soluble coffee residues represent a significant quantity all over the world. Silver skin and spent coffee grounds (SCG) are the main residues of the coffee industry. The many organic compounds contained in coffee residues suggest that their recovery and use could be very beneficial. Indeed, thanks to their composition, they can be used in the production of biodiesel, as a source of sugar, as a precursor for the creation of active carbon or as a sorbent for the removal of metals. After a careful evaluation of the possible uses of coffee grounds, the aim of this research was to show a broad characterization of coffee waste for energy purposes through physical and chemical analyses that highlight the most significant quality indexes, the interactions between them and the quantification of their importance. Results identify important tools for the qualification and quantification of the effects of coffee waste properties on energy production processes. They show that (SCG) are an excellent raw material as biomass, with excellent values in terms of calorific value and low ash content, allowing the production of 98% coffee pellets that are highly suitable for use in thermal conversion systems. Combustion tests were also carried out in an 80kWth boiler and the resulting emissions without any type of abatement filter were characterized.

6.
Oncogene ; 20(16): 2010-22, 2001 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-11360185

RESUMEN

Protein kinase CK2 is an ubiquitous and pleiotropic Ser/Thr protein kinase composed of two catalytic (alpha and/or alpha') and two regulatory (beta) subunits generally combined to form alpha(2)beta(2), alphaalpha'beta(2), or alpha'(2)beta(2) heterotetramers. To gain more insight into the role of CK2 in the control of proliferation in mammalian cells, overexpression of isolated CK2 subunits alpha, alpha', or beta was carried out in two fibroblast cell lines: NIH3T3 and CCL39. To interfere with CK2 cellular functions, cells were also transfected with a kinase-inactive mutant of CK2alpha catalytic subunit: CK2alpha-K68A. In NIH3T3 cells, overexpression of either wild-type subunit (alpha, alpha' or beta) had no effect on cell proliferation. In contrast, overexpression of the CK2alpha kinase-deficient mutant induced a marked inhibition of cell proliferation. This resulted from a defect in G1/S progression as demonstrated in transient transfection experiments in both NIH3T3 and CCL39 cells using BrdU incorporation measurements and in CCL39 clones stably overexpressing the CK2alpha-K68A mutant by growth curve analysis. We demonstrated that the kinase-negative mutant has the capacity to integrate the endogenous CK2 subunit pool both as an isolated kinase-inactive alpha subunit and as associated to the beta subunit in a kinase-inactive tetramer. Finally we showed that expression of the kinase-inactive mutant interferes with phosphorylation of an endogenous CK2 substrate; we speculate that optimal phosphorylation of target proteins by CK2 is required to achieve optimal cell cycle progression.


Asunto(s)
División Celular/fisiología , Proteínas Serina-Treonina Quinasas/fisiología , Células 3T3/citología , Células 3T3/enzimología , Animales , Quinasa de la Caseína II , Dominio Catalítico , Cricetinae , Ratones , Mutación , Fosforilación , Pruebas de Precipitina , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Transfección
7.
FEBS Lett ; 449(1): 61-5, 1999 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-10225429

RESUMEN

We previously showed that the cannabinoid receptor CB1 stably transfected in Chinese hamster ovary cells was constitutively active and could be inhibited by the inverse agonist SR 141716A. In the present study, we demonstrate that the cannabinoid agonist CP-55940 induced cytosol alkalinization of CHO-CB1 cells in a dose- and time-dependent manner via activation of the Na+/H+ exchanger NHE-1 isoform. By contrast, the inverse agonist SR 141716A induced acidification of the cell cytosol, suggesting that the Na+/H+ exchanger NHE-1 was constitutively activated by the CB1 receptor. CB1-mediated NHE1 activation was prevented by both pertussis toxin treatment and the specific MAP kinase inhibitor PD98059. NHE-1 and p42/p44 MAPK had a similar time course of activation in response to the addition of CP-55940 to CHO-CB1 cells. These results suggest that CB1 stimulates NHE-1 by G(i/o)-mediated activation of p42/p44 MAP kinase and highlight a cellular physiological process targeted by CB1.


Asunto(s)
Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Cannabinoides/metabolismo , Receptores de Droga/metabolismo , Transducción de Señal , Intercambiadores de Sodio-Hidrógeno/metabolismo , Animales , Células CHO , Cricetinae , Ciclohexanoles/farmacología , Concentración de Iones de Hidrógeno , Piperidinas/farmacología , Isoformas de Proteínas , Pirazoles/farmacología , Receptores de Cannabinoides , Receptores de Droga/genética , Rimonabant
8.
J Endocrinol ; 119(3): 439-45, 1988 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-2851637

RESUMEN

Cyclic AMP levels were measured in freshly isolated hepatocytes of the rainbow trout. Compared with basal values, the average levels were increased up to 60 times in a dose-dependent manner either by mammalian glucagon (concentration range 1 nmol-1 mumol/l; dose giving half maximum response (EC50) 0.18 mumol/l) or by forskolin (concentration range 0.1-100 mumol/l; EC50 about 10 mumol/l). These stimulatory effects were partially inhibited by fish or mammalian neurohypophysial hormones used at relatively high concentrations (1-5 mumol/l). It is suggested that these results are evidence for the presence of V1-type receptors in fish hepatocytes. Together with previous results obtained with gills on the hormonal inhibition of adenylate cyclase activity, they suggest that teleost fish may possess only V1-type receptors (or two V1-related types), while the V2 receptors have evolved (or have become functional) in higher vertebrates.


Asunto(s)
AMP Cíclico/metabolismo , Hígado/efectos de los fármacos , Hormonas Neurohipofisarias/farmacología , Salmonidae/fisiología , Trucha/fisiología , Animales , Colforsina/farmacología , Depresión Química , Relación Dosis-Respuesta a Droga , Glucagón/farmacología , Humanos , Técnicas In Vitro , Factores de Tiempo
9.
Minerva Chir ; 55(9): 599-605, 2000 Sep.
Artículo en Italiano | MEDLINE | ID: mdl-11155473

RESUMEN

BACKGROUND: Prophylactic antibiotics are recommended for clean-contaminated and selected contaminated surgery. In clean surgery antibiotics are suggested if the operation involves the insertion of prosthetic devices and a potential infection is expected to cause serious morbidity or mortality. Inguinal hernia repair is a clean operation, infections are rare; they can usually be cured without removing the prosthesis and recurrence is uncommon even after removal of the mesh. Aim of the study is to evaluate whether the lack of antimicrobial prophylaxis increases the risk of postoperative infections in patients treated for groin hernia, compared to those treated with prophylaxis. METHODS: One hundred and forty-eight patients underwent inguinal hernia repair with mesh: 64 patients (43%) received 2 g cefotaxime by intravenous bolus about 30 minutes before the operation, 84 patients (57%) did not receive any antimicrobic prophylaxis. Mean follow-up was 13 months (range 1-31 months) for both groups. RESULTS: We did not observe any major complication. Among both groups, no patient had developed infection at one week and one month after surgery. CONCLUSIONS: In personal experience, any advantage in terms of prevention of infections with antibiotic prophylaxis in patients operated on for groin hernia has been observed. A review of the literature showed no general agreement on this subject with different risk of infections in different trials. A new prospective randomized trial is necessary to clarify this topic.


Asunto(s)
Profilaxis Antibiótica , Hernia Inguinal/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo
10.
Recenti Prog Med ; 85(6): 328-32, 1994 Jun.
Artículo en Italiano | MEDLINE | ID: mdl-8047681

RESUMEN

The authors describe three cases of reflex sympathetic dystrophy of the upper extremity associated with barbiturate therapy and evidence their common clinical aspects and differences. The most recent knowledge and the most important literature relating to this subject are also reported. On the basis of these, personal observations are discussed and some pathogenetic hypotheses formulated.


Asunto(s)
Barbitúricos/efectos adversos , Distrofia Simpática Refleja/inducido químicamente , Anciano , Brazo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Fenobarbital/efectos adversos , Distrofia Simpática Refleja/diagnóstico
11.
Tissue Cell ; 45(6): 371-82, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23916093

RESUMEN

Spermatogenesis in Lake Magadi tilapia (Alcolapia grahami), a cichlid fish endemic to the highly alkaline and saline Lake Magadi in Kenya, was evaluated using light and transmission electron microscopy. Spermatogenesis, typified by its three major phases (spermatocytogenesis, meiosis and spermiogenesis), was demonstrated by the presence of maturational spermatogenic cells namely spermatogonia, spermatocytes, spermatids and spermatozoa. Primary spermatogonia, the largest of all the germ cells, underwent a series of mitotic divisions producing primary spermatocytes, which then entered two consecutive meiotic divisions to produce secondary spermatocytes and spermatids. Spermatids, in turn, passed through three structurally distinct developmental stages typical of type-I spermiogenesis to yield typical primitive anacrosomal spermatozoa of the externally fertilizing type (aquasperm). The spermatozoon of this fish exhibited a spheroidal head with the nucleus containing highly electron-dense chromatin globules, a midpiece containing ten ovoid mitochondria arranged in two rows and a flagellum formed by the typical 9 + 2 microtubule axoneme. In addition, the midpiece, with no cytoplasmic sheath, appeared to end blindly distally in a lobe-like pattern around the flagellum; a feature that was unique and considered adaptive for the spermatozoon of this species to the harsh external environment. These observations show that the testis of A. grahami often undergoes active spermatogenesis despite the harsh environmental conditions to which it is exposed on a daily basis within the lake. Further, the spermiogenic features and spermatozoal ultrastructure appear to be characteristic of Cichlidae and, therefore, may be of phylogenetic significance.


Asunto(s)
Meiosis , Espermatogénesis , Espermatozoides/ultraestructura , Tilapia , Animales , Humanos , Lagos , Masculino , Filogenia , Espermátides/ultraestructura , Testículo/crecimiento & desarrollo
13.
J Exp Biol ; 196: 337-45, 1994 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-7823032

RESUMEN

Na+/H+ exchangers (NHE), also called antiporters, are vital transmembrane transporters involved in multiple cellular functions including the regulation of intracellular pH, the control of cell volume and transepithelial ion transport. These transporters are highly regulated by a remarkably wide variety of stimuli which can modulate their expression level and activity. Five isoforms of Na+/H+ exchangers have been cloned and characterized to date; they define a new gene family of vertebrate transporters. These isoforms share the same overall structure but exhibit differences with respect to amiloride-sensitivity, cellular localization, kinetic variables, regulation by various stimuli and plasma membrane targeting in polarized epithelial cells. Biochemical techniques and molecular genetics tools provide the means of analyzing these transporters at the molecular level. The purpose of this manuscript is to give an overview of the main features of the Na+/H+ exchangers with emphasis on recent advances in comprehension of the structure-function relationship and regulation mechanisms of the ubiquitous isoform: NHE-1.


Asunto(s)
Familia de Multigenes , Estructura Secundaria de Proteína , Intercambiadores de Sodio-Hidrógeno/biosíntesis , Intercambiadores de Sodio-Hidrógeno/química , Animales , Regulación de la Expresión Génica , Hormonas/farmacología , Humanos , Especificidad de Órganos , Vertebrados
14.
J Biol Chem ; 268(5): 3357-63, 1993 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-8429012

RESUMEN

Activated phagocytes produce large amounts of reactive oxygen intermediates, including peroxides. In addition to their microbicidal effect, it has recently been suggested that reactive oxygen species play a role as intracellular messengers. The mechanism of action remains unknown, but peroxides have been reported to increase tyrosine phosphorylation, an effect potentiated by vanadate. In this report we studied the effects of a combination of H2O2 and vanadate on Ca2+ homeostasis in granulocytic HL60 cells. The peroxides induced a transient elevation of cytosolic [Ca2+] associated with release from internal stores. Ca2+ mobilization was accompanied by increased generation of inositol 1,4,5-trisphosphate, implicating phospholipase C (PLC). A sizable increase in phosphotyrosine accumulation by several polypeptides in the M(r) 20,000 to 250,000 range preceded the [Ca2+] changes. We therefore considered the possibility that tyrosine phosphorylation of a phospholipase mediates the observed effects. Differentiated (granulocytic) HL60 cells did not have detectable levels of PLC gamma 1 but had substantial PLC gamma 2. Immunoprecipitation and immunoblotting experiments demonstrated that PLC gamma 2 becomes tyrosine-phosphorylated upon treatment of the cells with peroxides of vanadate. If associated with activation, such phosphorylation of PLC gamma 2 can account for the rise in [Ca2+]. Although capable of mobilizing internal Ca2+ stores, the peroxides failed to produce the sustained [Ca2+] increase predicted by the "capacitative" model. Mn2+ influx determinations indicated that this is due to impairment of divalent cation entry by the peroxides, uncoupling the plasma membrane from the internal stores. Changes in [Ca2+] homeostasis could mediate some of the messenger actions of reactive oxygen species.


Asunto(s)
Calcio/metabolismo , Isoenzimas/metabolismo , Fosfolipasas de Tipo C/metabolismo , Tirosina , Secuencia de Aminoácidos , Transporte Biológico/efectos de los fármacos , ATPasas Transportadoras de Calcio/antagonistas & inhibidores , Citosol/metabolismo , Homeostasis , Humanos , Inositol 1,4,5-Trifosfato/metabolismo , Cinética , Leucemia Promielocítica Aguda , Manganeso/farmacología , Datos de Secuencia Molecular , N-Formilmetionina Leucil-Fenilalanina/farmacología , Fosforilación , Terpenos/farmacología , Tapsigargina , Células Tumorales Cultivadas , Vanadatos/farmacología
15.
J Comp Physiol B ; 160(1): 93-8, 1990.
Artículo en Inglés | MEDLINE | ID: mdl-2162361

RESUMEN

Na+, K+ exchanges were studied in isolated hepatocytes of the rainbow trout, Salmo gairdneri. Ouabain at 10(-4) M produced maximal inhibition (95%) of K+ uptake and enhanced intracellular Na+ accumulation, showing that active fluxes account for a very large proportion of Na+ and K+ exchanges. Inhibition of the Na-K pump by ouabain was significant at low concentrations (10(-8) M). When external K+ concentration was reduced from 7 mM to 0.5 mM, half maximum inhibition (IC50) of K+ uptake was obtained at a 22-fold lower concentration of ouabain confirming that ouabain and potassium compete at the same pump site. Time-course analysis of [3H]ouabain binding indicated a two-component kinetics: one component saturable and dependent on K+ concentration in the medium, the other linear and independent of external K+. The ouabain binding site number, determined by Scatchard plots, remained constant (ca. 2.5 x 10(5) per cell) and independent of the external K+ concentration (7, 0.5 or 0 mM), while the dissociation constant (KD) decreased from 4.2 microM to 7.3 nM when K+ was removed from the Hank's medium. These ouabain binding sites are characterized by an exceptionally low turnover rate (400 min-1), as estimated from ouabain-sensitive K+ flux, in comparison to those described in other cell types of higher vertebrates. At each external K+ concentration studied, the inhibition of K+ uptake and ouabain binding measured as a function of ouabain concentration indicated a strict correlation between the degree of K pump inhibition and the amount of bound glycoside.


Asunto(s)
Hígado/metabolismo , Ouabaína/metabolismo , Salmonidae/metabolismo , Trucha/metabolismo , Animales , Sitios de Unión , Transporte Biológico Activo/efectos de los fármacos , Técnicas In Vitro , Intercambio Iónico , Cinética , Hígado/citología , Hígado/efectos de los fármacos , Ouabaína/farmacología , Potasio/metabolismo , Canales de Potasio/efectos de los fármacos , Canales de Potasio/metabolismo , Sodio/metabolismo , Canales de Sodio/efectos de los fármacos , Canales de Sodio/metabolismo
16.
J Biol Chem ; 272(1): 271-9, 1997 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-8995258

RESUMEN

The ubiquitously expressed Na+/H+ exchanger NHE1 is the target of multiple signaling pathways, including those activated by tyrosine kinase receptors, G protein-coupled receptors, and integrins. The intracellular pathways leading to activation of NHE1 are poorly understood. To gain more insight into these activation pathways, we examined the role of mitogen-activated protein kinases (MAPKs) as potential mediators of NHE1 activation by extracellular stimuli such as growth factors and hyperosmotic stress. Whereas p44 MAPK does not appear to phosphorylate NHE1 in vitro, we found that inhibition of the p42/p44 MAPK signaling by expression of a dominant negative form of p44 MAPK, by expression of the MAP kinase phosphatase MKP-1, or by inhibition of MAPK kinase 1 (MKK1) with the PD 98059 compound reduced by 50-60% NHE1 activation in response to growth factors. This inhibitory effect also was observed in C-terminal NHE1 deletion mutants in which the major phosphorylation sites have been deleted. Furthermore, the use of a CCL39-derived cell line expressing an estradiol-regulated form of oncogenic Raf-1 (CCL39-deltaRaf-1:ER) revealed that the exclusive activation of the Raf --> MKK1 --> p42/p44 MAPK cascade was capable of inducing NHE1 activation to the same extent as potent growth factors like thrombin. Together, our findings demonstrate that the p42/p44 MAPK cascade plays a predominant role in the regulation of NHE1 by growth factors, an action that is mediated via accessory proteins that remain to be identified. In contrast, we found no evidence in favor of the contribution of any MAPK, p42/p44, p38 MAPKs, and Jun kinase, in NHE1 activation by osmotic stress.


Asunto(s)
Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Sustancias de Crecimiento/farmacología , Quinasas de Proteína Quinasa Activadas por Mitógenos , Proteínas Quinasas Activadas por Mitógenos , Intercambiadores de Sodio-Hidrógeno/metabolismo , Animales , Línea Celular , Cricetinae , Cricetulus , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Estradiol/farmacología , Flavonoides/farmacología , Insulina/farmacología , Proteínas Quinasas JNK Activadas por Mitógenos , MAP Quinasa Quinasa 1 , Proteína Quinasa 3 Activada por Mitógenos , Fosforilación , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-raf , Eliminación de Secuencia , Transducción de Señal , Sorbitol/farmacología , Relación Estructura-Actividad , Trombina/farmacología , Equilibrio Hidroelectrolítico , Proteínas Quinasas p38 Activadas por Mitógenos
17.
J Exp Biol ; 157: 335-48, 1991 May.
Artículo en Inglés | MEDLINE | ID: mdl-2061705

RESUMEN

Isolated trout hepatocytes when swollen in hypotonic medium undergo a regulatory volume decrease (RVD), which occurs via KCl loss. The system shows characteristics similar to those of the transporter described in red cells. This led us to investigate, in trout hepatocytes, the effect of another signal known to activate this flux in red cells, i.e. treatment with the sulphhydryl-group reagent N-ethylmaleimide (NEM). NEM treatment resulted in a striking increase in ouabain-resistant K+ uptake measured by an isotope pulse uptake technique. The time course of the response to NEM was similar to that obtained with a hypotonic shock, indicating that the effect of NEM was immediate and transient. The NEM-stimulated K+ influx demonstrated the same anion sensitivity as the volume-induced K+ influx, i.e. a specific requirement for Br- or Cl-. Efflux experiments showed that NEM treatment produced a stimulation of both K+ and Cl- effluxes leading to a substantial net loss (10%) of cellular KCl, as confirmed by analysis of ionic contents. This KCl loss is consistent with the rapid cell shrinkage observed after addition of NEM. The Cl--dependent K+ influx was found to be independent of external Na+; in addition, NEM had no effect on Na+ content, indicating that Na+ is not implicated in this process. The effect of loop diuretics was tested on the NEM-stimulated K+ influx. As observed for the volume-induced K+ flux, a high concentration of furosemide (10(-3) mol l-1) is required for full inhibition of this flux; no effect was obtained with bumetanide (10(-4) mol l-1). Consequently, NEM appears to activate a KCl cotransport similar to the one induced in hypotonically swollen cells. Finally, the combination of the two treatments, NEM and hypotonic shock, was found to increase the K+ fluxes even further, suggesting additivity of the two stimuli by mutual positive interaction.


Asunto(s)
Calcio/metabolismo , Etilmaleimida/farmacología , Hígado/efectos de los fármacos , Potasio/metabolismo , Animales , Agua Corporal/metabolismo , Bumetanida/farmacología , Células Cultivadas , Furosemida/farmacología , Hígado/citología , Hígado/metabolismo , Trucha
18.
Biochem J ; 301 ( Pt 2): 539-44, 1994 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-8043000

RESUMEN

Activated phagocytes undergo a massive burst of metabolic acid generation, yet must be able to maintain their cytosolic pH (pHi) within physiological limits. Peroxides of vanadate (V(4+)-OOH), potent inhibitors of phosphotyrosine phosphatases, have recently been shown to produce activation of the respiratory burst in HL60 granulocytes. We therefore investigated the effects of V(4+)-OOH on pHi homoeostasis in HL60 granulocytes, using a pH-sensitive fluorescent dye. V(4+)-OOH stimulation induced a biphasic pH change: a transient cytosolic acidification followed by a significant alkalinization. The initial acidification was prevented by inhibition of the NADPH oxidase and was absent in undifferentiated cells lacking oxidase activity. Analysis of the alkalinization phase demonstrated the involvement of the Na+/H+ antiporter, and also provided evidence for activation of two alternative H(+)-extrusion pathways: a bafilomycin-sensitive component, likely reflecting vacuolar-type H(+)-ATPase activity, and a Zn(2+)-sensitive H(+)-conductive pathway. Our results indicate that V(4+)-OOH stimulation not only activated the NADPH oxidase but concomitantly stimulated H(+)-extrusion pathways, enabling the cells to compensate for the massive production of intracellular H+ associated with the respiratory burst.


Asunto(s)
Granulocitos/metabolismo , Proteínas Tirosina Fosfatasas/antagonistas & inhibidores , Vanadatos/farmacología , Medios de Cultivo , Activación Enzimática/efectos de los fármacos , Colorantes Fluorescentes , Granulocitos/efectos de los fármacos , Humanos , Concentración de Iones de Hidrógeno , NADH NADPH Oxidorreductasas/antagonistas & inhibidores , NADH NADPH Oxidorreductasas/metabolismo , NADPH Oxidasas , Compuestos Onio/farmacología , ATPasas de Translocación de Protón/metabolismo , Sodio/farmacología , Intercambiadores de Sodio-Hidrógeno/metabolismo , Células Tumorales Cultivadas , Vacuolas/enzimología , Zinc/farmacología
19.
J Exp Biol ; 137: 303-18, 1988 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-3209971

RESUMEN

Isolated trout hepatocytes exposed to hypotonic Hank's medium (isotonicity x 0.70) swelled to 1.17 times the control volume after 3 min; by 15 min the cell volume had returned to normal. The ouabain-insensitive K+ uptake increased, indicating an immediate rise in K+ membrane permeability. As indicated by analysis of cellular contents, the regulatory volume decrease (RVD) was ensured by a release of intracellular K+. Na+ was not implicated in this mechanism. This potassium permeability induced by hypotonic shock was transient (maximum at 6 min), insensitive to blocking agents of voltage- and Ca2+-dependent K+ channels, and chloride-dependent. This result, together with a time-course of Cl- uptake similar to that of K+, suggests a K+/Cl- cotransport mechanism. This cotransport is inhibited by high furosemide concentrations (10(-3) mol l-1) but not by bumetanide (10(-4) mol l-1) or piretanide (10(-4) mol l-1).


Asunto(s)
Cloruros/metabolismo , Hígado/metabolismo , Potasio/metabolismo , Animales , Transporte Biológico , Células Cultivadas , Soluciones Hipotónicas , Líquido Intracelular/metabolismo , Concentración Osmolar , Rubidio/metabolismo , Sodio/metabolismo , Trucha
20.
Minerva Pediatr ; 42(6): 219-25, 1990 Jun.
Artículo en Italiano | MEDLINE | ID: mdl-2250628

RESUMEN

One hundred twenty-seven children born between September 1st 1980 and August 31st 1985 weighing less than or equal to 1500 g at birth and submitted to intensive neonatal care were followed-up to the age of 12-36 months of corrected age with a follow-up program to assess their neuromotor and cognitive development. The incidence of cerebral palsy (CP) in the population in question was 15.7% at 12 and 24 months and 14.6% at 36 months. A peak CP rate was observed among those born in 1982 with a steady decline in the number of CP cases among those born in the last years of this study. The group of children with a birth weight of 1001-1500 g (VLBWI) was more heavily affected by CP than those whose weight was less than or equal to 1000 g (ELBWI). Statistical analysis revealed a significant correlation between neuromotor development and the following factors relative to the perinatal period: type of birth, sex, respiratory distress requiring assisted ventilation, acidosis, ultrasound, neurological examination at the 40th week of gestational age.


Asunto(s)
Parálisis Cerebral/epidemiología , Desarrollo Infantil , Recién Nacido de Bajo Peso , Factores de Edad , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Lactante , Recién Nacido , Italia , Masculino , Factores Sexuales , Factores de Tiempo
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