RESUMEN
Rhinoncomimus latipes Korotyaev (Coleoptera: Curculionidae), a biological control agent of mile-a-minute weed, Persicaria perfoliata (L.) H. Gross, has been mass reared with no infusion of new genetic material for 8-9 yr (at least 24-36 generations), while insects from the same genetic stock have been subject to field conditions in North America for that same period of time. Our main objective was to compare the laboratory population with the field population (and in 1 yr with a Chinese field population) to determine whether genetic changes had occurred, especially ones that may reduce the effectiveness of the laboratory population when released in the field. The laboratory insects laid more eggs and had reduced survival compared with field weevils in several comparisons, and had reduced responsiveness to cues that induce reproductive diapause. Exposure to older plants had the greatest effect on induction of reproductive diapause in both laboratory and field weevils, with effects of daylength and temperature less pronounced. At least a portion of the laboratory weevil population overwintered successfully. Results suggest that it is not necessary to add wild-type genetic material to the rearing colony at this time.
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Agentes de Control Biológico , Aptitud Genética , Polygonaceae/crecimiento & desarrollo , Control de Malezas , Gorgojos/fisiología , Animales , China , Frío , Diapausa de Insecto , Ambiente , Conducta Alimentaria , Femenino , Larva/genética , Larva/fisiología , Larva/efectos de la radiación , Masculino , Fotoperiodo , Estados Unidos , Gorgojos/genética , Gorgojos/efectos de la radiaciónRESUMEN
Reducing the incidence of healthcare-associated infection represents a major challenge. This systematic review of the evidence base considers the clinical effectiveness of incorporating an alcohol-based hand hygiene product into procedures aimed at improving compliance with hand hygiene guidelines, and thereby reducing the incidence of healthcare-associated infections. Multi-component interventions that included alcohol-based products were as effective as those that did not, both in achieving sustained hand hygiene compliance and in reducing infection rates. However, a number of difficulties were encountered in assessing hand hygiene studies: the problem of attributing efficacy to an alcohol-based product when used in a multi-component intervention; the variability inherent in the design of such studies; and how to use data from uncontrolled, unblinded studies in the assessment.
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Alcoholes/farmacología , Infección Hospitalaria/prevención & control , Desinfectantes/farmacología , Desinfección de las Manos/métodos , HumanosRESUMEN
We report that liquids perform self-propelled motion when they are placed in contact with hot surfaces with asymmetric (ratchetlike) topology. The pumping effect is observed when the liquid is in the Leidenfrost regime (the film-boiling regime), for many liquids and over a wide temperature range. We propose that liquid motion is driven by a viscous force exerted by vapor flow between the solid and the liquid.
RESUMEN
OBJECTIVE: To evaluate the safety and efficacy of the tumor necrosis factor fusion protein etanercept in children with treatment-resistant uveitis. METHODS: Ten children with chronic active uveitis (7 girls and 3 boys, mean age 7.5 years [range 3-12 years]) were enrolled in this prospective study. In 7 children, uveitis was associated with pauciarticular juvenile rheumatoid arthritis. Five children were antinuclear antibody positive. All patients had failed previous therapy with topical steroids and methotrexate and/or cyclosporine. All were treated with etanercept at a dosage of 0.4 mg/kg twice weekly for the first 3 months, and then, if eyes did not improve, with 25 mg twice weekly (mean 1.1 mg/kg) for at least 3 additional months. RESULTS: At the beginning of the trial, uveitis affected 18 eyes in the 10 children. Within 3 months, 10 of 16 affected eyes (63%; P = 0.017) showed a rapid decrease in anterior chamber cell density, including remission of uveitis in 4 eyes. In children with visual acuity of less than 20/25, 4 of 10 eyes (40%) improved. An exacerbation of uveitis during etanercept therapy occurred in only 1 child (1 of 14 eyes [7%]). Other ocular outcome parameters, such as intraocular pressure, synechia formation, and lens clarity, remained unchanged. Following a dosage increase to an average of 1.1 mg/kg after 3 months in 7 children, no further improvement was noted. CONCLUSION: Our data suggest that etanercept injected subcutaneously twice a week has a beneficial effect on treatment-resistant chronic uveitis in children. Further controlled studies with etanercept in systemic or topical form are necessary to confirm its efficacy and optimal mode of administration.
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Antirreumáticos/uso terapéutico , Artritis Juvenil/tratamiento farmacológico , Inmunoglobulina G/uso terapéutico , Receptores del Factor de Necrosis Tumoral/uso terapéutico , Uveítis Anterior/tratamiento farmacológico , Administración Tópica , Antirreumáticos/administración & dosificación , Artritis Juvenil/complicaciones , Niño , Preescolar , Ciclosporina/uso terapéutico , Etanercept , Femenino , Glucocorticoides/administración & dosificación , Glucocorticoides/uso terapéutico , Humanos , Inmunoglobulina G/administración & dosificación , Inyecciones Subcutáneas , Masculino , Metotrexato/uso terapéutico , Receptores del Factor de Necrosis Tumoral/administración & dosificación , Proteínas Recombinantes , Resultado del Tratamiento , Uveítis Anterior/etiología , Trastornos de la Visión/tratamiento farmacológico , Trastornos de la Visión/etiología , Agudeza VisualAsunto(s)
Colorantes/química , Transferencia de Energía/fisiología , Potenciales de la Membrana/fisiología , Mitocondrias/fisiología , Antibacterianos/farmacología , Ácido Bongcréquico/farmacología , Calcio/metabolismo , Carbonil Cianuro m-Clorofenil Hidrazona/farmacología , Línea Celular , Colorantes/metabolismo , Ciclosporina/farmacología , Inhibidores Enzimáticos/farmacología , Humanos , Membranas Intracelulares/fisiología , Ionomicina/farmacología , Ionóforos/farmacología , Mitocondrias/efectos de los fármacos , Permeabilidad , Rodaminas/farmacología , Rojo de Rutenio/farmacología , Espectrometría de Fluorescencia/métodosRESUMEN
The development of scanning probe techniques has made it possible to examine protein-protein interactions at the level of individual molecular pairs. A calibrated optical tweezers, along with immunoglobulin G (IgG)-coated polystyrene microspheres, has been used to detect individual surface-linked Staphylococcus protein A (SpA) molecules and to characterize the strength of the noncovalent IgG-SpA bond. Microspheres containing, on average, less than one IgG per contact area were held in the optical trap while an SpA-coated substrate was scanned beneath them at a distance of approximately 50 nm. This geometry allows the trapped bead to make contact with the surface, from bond formation to rupture, and results in an enhancement of the force applied to a bond due to leverage supplied by the bead itself. Experiments yielded median single-bond rupture forces from 25 to 44 pN for IgG from four mammalian species, in general agreement with predictions based on free energies of association obtained from solution equilibrium constants.
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Inmunoglobulina G/química , Inmunoglobulina G/inmunología , Rayos Láser , Óptica y Fotónica/instrumentación , Proteína Estafilocócica A/química , Proteína Estafilocócica A/inmunología , Animales , Calibración , Cabras , Ratones , Microesferas , Estructura Molecular , Probabilidad , Unión Proteica , Conejos , Staphylococcus aureus , Porcinos , TermodinámicaRESUMEN
Mitochondria buffer large changes in [Ca(2+)](i)following an excitotoxic glutamate stimulus. Mitochondrial sequestration of [Ca(2+)](i)can beneficially stimulate oxidative metabolism and ATP production. However, Ca(2+)overload may have deleterious effects on mitochondrial function and cell survival, particularly Ca(2+)-dependent production of reactive oxygen species (ROS) by the mitochondria. We recently demonstrated that the mitochondrial Na(+)-Ca(2+)exchanger in neurons is selectively inhibited by CGP-37157, a benzothiazepine analogue of diltiazem. In the present series of experiments we investigated the effects of CGP-37157 on mitochondrial functions regulated by Ca(2+). Our data showed that 25 microM CGP-37157 quenches DCF fluorescence similar to 100 microM glutamate and this effect was enhanced when the two stimuli were applied together. CGP-37157 did not increase ROS generation and did not alter glutamate or 3mM hydrogen-peroxide-induced increases in ROS as measured by DHE fluorescence. CGP-37157 induces a slight decrease in intracellular pH, much less than that of glutamate. In addition, CGP-37157 does not enhance intracellular acidification induced by glutamate. Although it is possible that CGP-37157 can enhance mitochondrial respiration both by blocking Ca(2+)cycling and by elevating intramitochondrial Ca(2+), we did not observe any changes in ATP levels or toxicity either in the presence or absence of glutamate. Finally, mitochondrial Ca(2+)uptake during an excitotoxic glutamate stimulus was only slightly enhanced by inhibition of mitochondrial Ca(2+)efflux. Thus, although CGP-37157 alters mitochondrial Ca(2+)efflux in neurons, the inhibition of Na(+)-Ca(2+)exchange does not profoundly alter glutamate-mediated changes in mitochondrial function or mitochondrial Ca(2+)content.
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Calcio/metabolismo , Clonazepam/análogos & derivados , Mitocondrias/metabolismo , Neuronas/metabolismo , Prosencéfalo/metabolismo , Intercambiador de Sodio-Calcio/antagonistas & inhibidores , Tiazepinas/farmacología , Adenosina Trifosfato/metabolismo , Animales , Transporte Biológico , Supervivencia Celular , Células Cultivadas , Clonazepam/farmacología , Glutamatos/farmacología , Concentración de Iones de Hidrógeno , Neurotoxinas/farmacología , Prosencéfalo/citología , Ratas , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/metabolismo , Sodio/metabolismoRESUMEN
The membrane-permeant oxidizing agent 2,2'-dithiodipyridine (DTDP) can induce Zn(2+) release from metalloproteins in cell-free systems. Here, we report that brief exposure to DTDP triggers apoptotic cell death in cultured neurons, detected by the presence of both DNA laddering and asymmetric chromatin formation. Neuronal death was blocked by increased extracellular potassium levels, by tetraethylammonium, and by the broad-spectrum cysteine protease inhibitor butoxy-carbonyl-aspartate-fluoromethylketone. N,N,N', N'-Tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) and other cell-permeant metal chelators also effectively blocked DTDP-induced toxicity in neurons. Cell death, however, was not abolished by the NMDA receptor blocker MK-801, by the intracellular calcium release antagonist dantrolene, or by high concentrations of ryanodine. DTDP generated increases in fluorescence signals in cultured neurons loaded with the zinc-selective dye Newport Green. The fluorescence signals following DTDP treatment also increased in fura-2- and magfura-2-loaded neurons. These responses were completely reversed by TPEN, consistent with a DTDP-mediated increase in intracellular free Zn(2+) concentrations. Our studies suggest that under conditions of oxidative stress, Zn(2+) released from intracellular stores may contribute to the initiation of neuronal apoptosis.
Asunto(s)
2,2'-Dipiridil/análogos & derivados , Apoptosis , Líquido Intracelular/metabolismo , Neuronas/metabolismo , Compuestos de Sulfhidrilo/metabolismo , Zinc/metabolismo , 2,2'-Dipiridil/toxicidad , Animales , Células Cultivadas , Quelantes/farmacología , Técnicas de Cocultivo , Fragmentación del ADN , Disulfuros/antagonistas & inhibidores , Disulfuros/toxicidad , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/farmacología , Colorantes Fluorescentes , L-Lactato Deshidrogenasa/metabolismo , N-Metilaspartato/toxicidad , Neuroglía/citología , Neuroglía/efectos de los fármacos , Neuronas/citología , Neuronas/efectos de los fármacos , Oxidación-Reducción/efectos de los fármacos , Potasio/metabolismo , Potasio/farmacología , Ratas , Canal Liberador de Calcio Receptor de Rianodina/metabolismo , Reactivos de Sulfhidrilo/antagonistas & inhibidores , Reactivos de Sulfhidrilo/toxicidad , Tetraetilamonio/farmacologíaRESUMEN
Increased intracellular free Zn(2+) ([Zn(2+)](i)) is toxic to neurons. Glia are more resistant to Zn(2+)-mediated toxicity; however, it is not known if this is because glia are less permeable to Zn(2+) or if glia possess intrinsic mechanisms that serve to buffer or extrude excess [Zn(2+)](i). We used the Zn(2+)-selective ionophore pyrithione to directly increase [Zn(2+)](i) in both neurons and astrocytes. In neurons, a 5-min exposure to 1 microM extracellular Zn(2+) in combination with pyrithione produced widespread toxicity, whereas extensive astrocyte injury was not observed until extracellular Zn(2+) was increased to 10 microM. Measurements with magfura-2 demonstrated that pyrithione increased [Zn(2+)](i) to similar levels in both cell types. We also measured how increased [Zn(2+)](i) affects mitochondrial membrane potential (Deltapsi(m)). In astrocytes, but not in neurons, toxic [Zn(2+)](i) resulted in an acute loss of Deltapsi(m), suggesting that mitochondrial dysregulation may be an early event in [Zn(2+)](i)-induced astrocyte but not neuronal death.
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Astrocitos/efectos de los fármacos , Neuronas/efectos de los fármacos , Zinc/toxicidad , Animales , Astrocitos/patología , Células Cultivadas , Embrión de Mamíferos , Colorantes Fluorescentes/farmacocinética , Fura-2/análogos & derivados , Fura-2/farmacocinética , Membranas Intracelulares/efectos de los fármacos , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Mitocondrias/efectos de los fármacos , Mitocondrias/ultraestructura , Neuronas/patología , Prosencéfalo , RatasRESUMEN
BACKGROUND: The objective of this study was to evaluate the pretreatment psychosocial functioning of women with premenstrual dysphoric disorder (PMDD) and the effect of sertraline treatment on psychosocial functioning in these patients. METHOD: Two hundred forty-three women recruited from 12 university-affiliated sites and meeting DSM-IV criteria for PMDD completed 1 cycle of single-blind placebo and were randomly assigned to flexible dose sertraline or placebo for 3 cycles. Psychosocial functioning was assessed by the Daily Record of Severity of Problems (DRSP), the Social Adjustment Scale (SAS), and the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q). RESULTS: SAS scores during the follicular phase were similar to SAS scores of community norms, whereas the pretreatment SAS and Q-LES-Q scores during the luteal phase were similar to scores of women with depressive disorders. Sertraline was significantly more effective than placebo in improving psychosocial functioning as measured by the SAS, the Q-LES-Q, and the 3 DRSP items of impaired productivity, interference with social activities, and interference with relationships with others. Improvement in psychosocial functioning assessed by SAS and Q-LES-Q correlated with improvement in symptomatology assessed by the Clinical Global Impressions-Improvement (CGI-I) scale and the Hamilton Rating Scale for Depression (HAM-D). Remitters (CGI-I score of 1) were more likely to function better at baseline and showed larger improvements in functioning and quality of life with treatment compared with nonremitters. CONCLUSION: Sertraline was superior to placebo in improving psychosocial functioning in women with PMDD as reflected by SAS, Q-LES-Q, and DRSP measures. Functional improvement correlated with improvement in premenstrual symptomatology and was apparent by the second cycle of treatment. Comparison of pretreatment SAS scores in women with PMDD with the scores of other populations of women documents the degree of luteal phase functional impairment in women with PMDD and a relative absence of follicular phase impairment.
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Adaptación Psicológica , Síndrome Premenstrual/tratamiento farmacológico , Síndrome Premenstrual/psicología , Inhibidores Selectivos de la Recaptación de Serotonina/uso terapéutico , Sertralina/uso terapéutico , Ajuste Social , Adulto , Femenino , Fase Folicular , Estado de Salud , Humanos , Fase Luteínica , Registros Médicos , Persona de Mediana Edad , Placebos , Síndrome Premenstrual/diagnóstico , Escalas de Valoración Psiquiátrica/estadística & datos numéricos , Calidad de Vida , Índice de Severidad de la Enfermedad , Resultado del TratamientoRESUMEN
Chromosomes are replicated in characteristic, temporal patterns during S phase. We have compared the timing of association of replication proteins at early- and late-replicating origins of replication. Minichromosome maintenance proteins assemble simultaneously at early- and late-replicating origins. In contrast, Cdc45p association with late origins is delayed relative to early origins. DNA polymerase alpha association is similarly delayed at late origins and requires Cdc45p function. Activation of the S phase checkpoint inhibits association of Cdc45p with late-firing origins. These studies suggest that Cdc45p is poised to serve as a key regulatory target for both the temporal and checkpoint-mediated regulation of replication origins.
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Proteínas Portadoras/genética , Ciclo Celular/genética , Cromosomas Fúngicos/genética , ADN Polimerasa I/genética , Replicación del ADN , Proteínas de Unión al ADN , Proteínas Nucleares/genética , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas Portadoras/metabolismo , ADN Polimerasa I/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fase G1 , Haploidia , Cinética , Mitosis , Proteínas Nucleares/metabolismo , Origen de RéplicaRESUMEN
We measured glutamate-stimulated increases in intracellular free Ca2+ concentrations ([Ca2+]i) in cultured rat forebrain neurons loaded with both a high- and a low-affinity Ca2+ indicator. In these dual-dye studies, the high-affinity indicators Fluo-3 and Fura-2 gave both qualitatively and quantitatively different results than the low-affinity indicators Mag-fura-2 and Calcium Green-5N. The glutamate-stimulated peak [Ca2+]i reported using Fluo-3 and Fura-2 were less than 6 microM while the low-affinity indicators Mag-fura-2 and Calcium Green-5N indicated [Ca2+]i responses were more than 12 microM. The shapes of the responses obtained with the two types of dyes were also different, and only the low-affinity indicators effectively demonstrated that [Ca2+]i continues to rise during prolonged (5-min) stimulations. These dual-dye studies also revealed that kainate- and depolarization-induced [Ca2+]i responses could be differentiated from glutamate responses only with the low-affinity indicators. These results suggest that Fluo-3 and Fura-2 underestimate [Ca2+]i induced by excitotoxic glutamate stimuli and that these responses are greater than have previously been reported. These studies also reveal, in contrast to previous reports, that excitotoxic stimuli do indeed cause increases in [Ca2+]i that are greater than those produced by non-toxic stimuli.
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Calcio/metabolismo , Ácido Glutámico/farmacología , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Neurotoxinas/farmacología , Compuestos de Anilina , Animales , Transporte Biológico/efectos de los fármacos , Transporte Biológico/fisiología , Agonistas de Aminoácidos Excitadores/farmacología , Colorantes Fluorescentes , Fura-2/análogos & derivados , Glicina/farmacología , Ácido Kaínico/farmacología , Magnesio/farmacología , Compuestos Orgánicos , Cloruro de Potasio/farmacología , Ratas , Ratas Sprague-Dawley , XantenosRESUMEN
The acidic environment inside secretory vesicles ensures that neuropeptides and peptide hormones are packaged in a concentrated condensed form. Although this is optimal for storage, decondensation limits release. Thus, it would be advantageous to alter the physical state of peptides in preparation for exocytosis. Here, we report that depolarization of the plasma membrane rapidly increases enhanced green fluorescent protein (EGFP)-tagged hormone fluorescence inside secretory vesicles. This effect requires Ca2+ influx and persists when exocytosis is inhibited by N-ethylmaleimide. Peptide deprotonation appears to produce this response, because it is not seen when the vesicle pH gradient is collapsed or when a pH-insensitive GFP variant is used. These data demonstrate that Ca2+ evokes alkalinization of the inside of secretory vesicles before exocytosis. Thus, Ca2+ influx into the cytoplasm alters the physical state of intravesicular contents in preparation for release.
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Factor Natriurético Atrial/metabolismo , Calcio/fisiología , Células PC12/metabolismo , Precursores de Proteínas/metabolismo , Animales , Factor Natriurético Atrial/genética , Membrana Celular/fisiología , Electrofisiología , Inhibidores Enzimáticos/farmacología , Etilmaleimida/farmacología , Exocitosis/efectos de los fármacos , Exocitosis/fisiología , Proteínas Fluorescentes Verdes , Concentración de Iones de Hidrógeno , Indicadores y Reactivos , Proteínas Luminiscentes/genética , Células PC12/fisiología , Precursores de Proteínas/genética , Protones , Ratas , Lugares Marcados de SecuenciaRESUMEN
The objectives of the present study were to determine whether angiotensin II (Ang II) modifies beta-adrenoceptor-induced cAMP production in preglomerular microvascular smooth muscle cells (PMVSMCs), to determine whether the Ang II/beta-adrenoceptor interaction on cAMP production differs in PMVSMCs from normotensive Wistar-Kyoto (WKY) rats vs. PMVSMCs from spontaneously hypertensive rats (SHR), and to elucidate the mechanism of Ang II/beta-adrenoceptor interactions on cAMP production in PMVSMCs. In cultured PMVSMCs, isoproterenol increased cAMP levels and this effect was markedly enhanced by Ang II. The Ang II enhancement of isoproterenol-induced cAMP was significantly greater in SHR PMVSMCs compared with WKY PMVSMCs. Neither inhibition of calcineurin with FK506, inhibition of calcium-calmodulin with W-7 and calmidazolium, nor inhibition of Gi proteins with pertussis toxin attenuated Ang II enhancement of isoproterenol-induced cAMP in PMVSMCs from either SHR or WKY rats. Moreover, the effect of Ang II on isoproterenol-induced cAMP was not mimicked by alpha-2 adrenoceptor stimulation. In contrast, chelation of intracellular calcium with BAPTA-AM attenuated, increasing intracellular calcium with A23187 augmented, and inhibition of protein kinase C with either calphostin C or chelerythrine chloride abolished Ang II enhancement of isoproterenol-induced cAMP. We conclude that in cultured PMVSMCs Ang II enhances the cAMP response to beta-adrenoceptor agonists via a mechanism that involves coincident activation of adenylyl cyclase by stimulatory G proteins and protein kinase C. Thus, protein kinase C-mediated activation of adenylyl cyclase may attenuate Ang II-induced vasoconstriction in the renal microcirculation by raising the intracellular levels of cAMP, and this mechanism may be augmented in genetic hypertension.
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Angiotensina II/farmacología , AMP Cíclico/biosíntesis , Hipertensión/metabolismo , Isoproterenol/farmacología , Glomérulos Renales/irrigación sanguínea , Músculo Liso Vascular/metabolismo , Animales , Calcio/metabolismo , Calmodulina/fisiología , Proteínas de Unión al GTP/fisiología , Masculino , Microcirculación/metabolismo , Ratas , Ratas Endogámicas SHR , Ratas Endogámicas WKYRESUMEN
1. We have examined the mechanisms by which cultured central neurones from embryonic rat brain buffer intracellular Ca2+ loads following kainate receptor activation using fluorescent indicators of [Ca2+]i and [Na+]i. 2. Stimulation of cultured forebrain neurones with 100 microM kainate produced a rapid increase in [Ca2+]i that displayed a variable rate of recovery. Kainate also increased [Na+]i with a response that was slightly slower in onset and markedly slower in recovery. 3. The recovery of [Ca2+]i to baseline was not very sensitive to the [Na+]i. The magnitude of the increase in [Na+]i in response to kainate did not correlate well with the [Ca2+]i recovery time, and experimental manipulations that altered [Na+]i did not have a large impact on the rate of recovery of [Ca2+]i. 4. The recovery of [Ca2+]i to baseline was accelerated by the mitochondrial Na+-Ca2+ exchange inhibitor CGP-37157, suggesting that the recovery rate is influenced by release of Ca2+ from a mitochondrial pool and also that variation in the recovery rate is related to the extent of mitochondrial Ca2+ loading. Kainate did not alter the mitochondrial membrane potential. 5. These studies reveal that mitochondria have a central role in buffering neuronal [Ca2+]i changes mediated by non-N-methyl-D-aspartate (NMDA) glutamate receptors, and that the variation in recovery times following kainate receptor activation reflects a variable degree of mitochondrial Ca2+ loading. However, unlike NMDA receptor-mediated Ca2+ loads, kainate receptor activation has minimal effects on mitochondrial function.
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Calcio/metabolismo , Agonistas de Aminoácidos Excitadores/farmacología , Ácido Kaínico/farmacología , Mitocondrias/fisiología , Neuronas/metabolismo , Prosencéfalo/metabolismo , Sodio/fisiología , Animales , Células Cultivadas , Clonazepam/análogos & derivados , Clonazepam/farmacología , Colorantes Fluorescentes , Potenciales de la Membrana/fisiología , Neuronas/efectos de los fármacos , Prosencéfalo/citología , Prosencéfalo/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Receptores de N-Metil-D-Aspartato/efectos de los fármacos , Receptores de N-Metil-D-Aspartato/metabolismo , Intercambiador de Sodio-Calcio/antagonistas & inhibidores , Estimulación Química , Tiazepinas/farmacologíaRESUMEN
We have investigated the role of mitochondrial calcium buffering in excitotoxic cell death. Glutamate acts at NMDA receptors in cultured rat forebrain neurons to increase the intracellular free calcium concentration. Although concurrent inhibition of mitochondrial calcium uptake substantially enhanced this cytoplasmic calcium increase, it significantly reduced glutamate-stimulated neuronal cell death. Mitochondrial inhibition did not affect nitric oxide production or MAP kinase phosphorylation, which have been proposed to mediate excitotoxicity. These results indicate that very high levels of cytoplasmic calcium are not necessarily toxic to forebrain neurons, and that potential-driven uptake of calcium into mitochondria is required to trigger NMDA-receptor-stimulated neuronal death.
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Calcio/metabolismo , Ácido Glutámico/envenenamiento , Mitocondrias/metabolismo , Neuronas/efectos de los fármacos , Neuronas/fisiología , Animales , Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Carbonil Cianuro p-Trifluorometoxifenil Hidrazona/farmacología , Muerte Celular/fisiología , Electrofisiología , Concentración de Iones de Hidrógeno , Membranas Intracelulares/fisiología , Mitocondrias/fisiología , Fármacos Neuroprotectores/farmacología , Óxido Nítrico Sintasa/metabolismo , Ratas/embriología , Ratas Sprague-DawleyRESUMEN
CONTEXT: Premenstrual dysphoric disorder is an important cause of symptoms and functional impairment in menstruating women. OBJECTIVE: To evaluate the efficacy of sertraline hydrochloride for treatment of premenstrual dysphoria by measuring changes in symptom expression and functional impairment. DESIGN: Two screening cycles followed by 1 single-blind placebo cycle and 3 cycles of randomized, double-blind, placebo treatment. SETTING: Twelve university-affiliated outpatient psychiatry and gynecology clinics. PATIENTS: Of the 447 women who requested participation, 243 met criteria for premenstrual dysphoric disorder and were randomized; 200 women completed the study. INTERVENTION: A flexible (50-150 mg) daily dose of sertraline hydrochloride. MAIN OUTCOME MEASURES: The Daily Record of Severity of Problems, Hamilton Rating Scale for Depression, Clinical Global Impression Scale, and Social Adjustment Scale. RESULTS: Mean (+/-SD) total daily symptom scores decreased significantly (P<.001) in the sertraline-treated (64+/-22 to 44+/-19) compared with the placebo-treated (62+/-22 to 54+/-24) groups. Significant improvement (P<.05) was found for all clinically derived symptom clusters (depressive, physical, and anger/irritability symptoms). Hamilton Rating Scale for Depression scores decreased by 44% and 29% in the sertraline and placebo groups, respectively (P<.002). End-point global ratings showed much or very much improvement in 62% of the active treatment group and 34% of the placebo treatment group (P<.001). Reported functional impairment was substantial at baseline. Improvement in psychosocial functioning with treatment was similar to what is found in studies of major depression. CONCLUSIONS: Sertraline was significantly better than placebo for treatment of premenstrual dysphoria as reflected by symptomatic improvement and change in reported functional impairment. Serotonin reuptake inhibitors such as sertraline are useful therapeutic options for women with premenstrual dysphoria.
Asunto(s)
1-Naftilamina/análogos & derivados , Síndrome Premenstrual/tratamiento farmacológico , Inhibidores Selectivos de la Recaptación de Serotonina/uso terapéutico , 1-Naftilamina/uso terapéutico , Adulto , Análisis de Varianza , Depresión , Método Doble Ciego , Eficiencia , Femenino , Humanos , Genio Irritable , Fase Luteínica , Síndrome Premenstrual/fisiopatología , Sertralina , Índice de Severidad de la Enfermedad , Ajuste SocialRESUMEN
Accumulation of intracellular Ca2+ is known to be critically important for the expression of NMDA receptor-mediated glutamate neurotoxicity. We have observed, however, that glutamate can also increase the neuronal intracellular Mg2+ concentration on activation of NMDA receptors. Here, we used conditions that elevate intracellular Mg2+ content independently of Ca2+ to investigate the potential role of Mg2+ in excitotoxicity in rat cortical neurons in vitro. In Ca2+-free solutions in which the Na+ was replaced by N-methyl-D-glucamine or Tris (but not choline), which also contained 9 mM Mg2+, exposure to 100 microM glutamate or 200 microM NMDA for 20 min produced delayed neuronal cell death. Neurotoxicity was correlated to the extracellular Mg2+ concentration and could be blocked by addition of NMDA receptor antagonists during, but not immediately following, agonist exposure. Finally, we observed that rat cortical neurons grown under different serum conditions develop an altered sensitivity to Mg2+-dependent NMDA receptor-mediated toxicity. Thus, the increase in intracellular Mg2+ concentration following NMDA receptor stimulation may be an underestimated component critical for the expression of certain forms of excitotoxic injury.