RESUMEN
When facial nerve axotomy (FNA) is performed on immunodeficient recombinase activating gene-2 knockout (RAG-2-/-) mice, there is greater facial motoneuron (FMN) death relative to wild type (WT) mice. Reconstituting RAG-2-/- mice with whole splenocytes rescues FMN survival after FNA, and CD4+ T cells specifically drive immune-mediated neuroprotection. Evidence suggests that immunodysregulation may contribute to motoneuron death in amyotrophic lateral sclerosis (ALS). Immunoreconstitution of RAG-2-/- mice with lymphocytes from the mutant superoxide dismutase (mSOD1) mouse model of ALS revealed that the mSOD1 whole splenocyte environment suppresses mSOD1 CD4+ T cell-mediated neuroprotection after FNA. The objective of the current study was to characterize the effect of CD4+ T cells on the central molecular response to FNA and then identify if mSOD1 whole splenocytes blocked these regulatory pathways. Gene expression profiles of the axotomized facial motor nucleus were assessed from RAG-2-/- mice immunoreconstituted with either CD4+ T cells or whole splenocytes from WT or mSOD1 donors. The findings indicate that immunodeficient mice have suppressed glial activation after axotomy, and cell transfer of WT CD4+ T cells rescues microenvironment responses. Additionally, mSOD1 whole splenocyte recipients exhibit an increased astrocyte activation response to FNA. In RAG-2-/-â¯+â¯mSOD1 whole splenocyte mice, an elevation of motoneuron-specific Fas cell death pathways is also observed. Altogether, these findings suggest that mSOD1 whole splenocytes do not suppress mSOD1 CD4+ T cell regulation of the microenvironment, and instead, mSOD1 whole splenocytes may promote motoneuron death by either promoting a neurotoxic astrocyte phenotype or inducing Fas-mediated cell death pathways. This study demonstrates that peripheral immune status significantly affects central responses to nerve injury. Future studies will elucidate the mechanisms by which mSOD1 whole splenocytes promote cell death and if inhibiting this mechanism can preserve motoneuron survival in injury and disease.
Asunto(s)
Linfocitos T CD4-Positivos/fisiología , Nervio Facial/inmunología , Nervio Facial/fisiología , Esclerosis Amiotrófica Lateral/inmunología , Animales , Axotomía/métodos , Linfocitos T CD4-Positivos/inmunología , Muerte Celular/fisiología , Supervivencia Celular/fisiología , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/fisiología , Modelos Animales de Enfermedad , Traumatismos del Nervio Facial , Núcleo Motor del Nervio Facial , Femenino , Ratones , Ratones Endogámicos C57BL , Neuronas Motoras/inmunología , Neuroprotección , Bazo/inmunología , Superóxido Dismutasa/genéticaRESUMEN
Latent infection from Toxoplasma gondii (T. gondii) is widespread worldwide and has been associated with cognitive deficits in some but not all animal models and in humans. We tested the hypothesis that latent toxoplasmosis is associated with decreased cognitive function in a large cross-sectional dataset, the National Health and Nutrition Examination Survey (NHANES). There were 4178 participants aged 20-59 years, of whom 19.1% had IgG antibodies against T. gondii. Two ordinary least squares (OLS) regression models adjusted for the NHANES complex sampling design and weighted to represent the US population were estimated for simple reaction time, processing speed and short-term memory or attention. The first model included only main effects of latent toxoplasmosis and demographic control variables, and the second added interaction terms between latent toxoplasmosis and the poverty-to-income ratio (PIR), educational attainment and race-ethnicity. We also used multivariate models to assess all three cognitive outcomes in the same model. Although the models evaluating main effects only demonstrated no association between latent toxoplasmosis and the cognitive outcomes, significant interactions between latent toxoplasmosis and the PIR, between latent toxoplasmosis and educational attainment, and between latent toxoplasmosis and race-ethnicity indicated that latent toxoplasmosis may adversely affect cognitive function in certain groups.
Asunto(s)
Trastornos del Conocimiento/complicaciones , Toxoplasmosis/complicaciones , Adulto , Distribución por Edad , Trastornos del Conocimiento/epidemiología , Estudios Transversales , Escolaridad , Humanos , Persona de Mediana Edad , Modelos Biológicos , Análisis Multivariante , Encuestas Nutricionales , Prevalencia , Grupos Raciales , Análisis de Regresión , Distribución por Sexo , Toxoplasmosis/epidemiología , Adulto JovenRESUMEN
Recent research has suggested that different cattle breed types may respond differently to anabolic implant protocols of varying intensity. Therefore, the purpose of this research was to compare anabolic implant protocols in feedlot steers of 2 different breed types. Sixty steers were stratified by weight and breed in a 2 × 3 factorial design examining 2 different breeds: Angus (AN; n=38) or Santa Gertrudis influenced (SG; n=22), and 3 implant strategies: no implant (CON; n=20), a moderate intensity implant protocol (d0 implant: Revalor-G, d56 implant: Revalor-IS, d112 implant: Revalor-S; MI; n=20), or a high intensity implant protocol (d0 implant: Revalor-IS, d56 implant: Revalor-S, d112 implant: Revalor-200; HI; n=20). Steers were randomly placed into pens equipped with GrowSafe bunks to collect dry matter intake and feeding behavior. All animals were fed the same diet. Weight, chute score, exit velocity, serum, rectal temperature, hip height and 12th rib fat thickness were collected approximately every 28 d over a 196 d period. Serum urea nitrogen (SUN) was evaluated as well. Total average daily gain was increased (P < 0.0001) in both the HI and MI steers compared to the CON steers by 29.4% and 26%, respectively. A treatment × breed interaction was observed (P < 0.0001) for hip height, with AN-CON steers being shorter (P < 0.0007) than AN-HI, SG-CON, SG-MI, and SG-HI steers. A breed × treatment interaction was observed (P < 0.004) for chute score and rectal temperature, with SG-HI and SG-MI steers having increased chute scores (P < 0.001) when compared to AN-HI, AN-MI, AN-CON, and SG-CON throughout the course of the trial. Additionally, SG-HI and SG-MI steers had an increased rectal temperature (P < 0.004) compared to AN-HI, AN-MI, AN-CON, and SG-CON steers. A breed effect was observed (P = 0.002) for SUN with AN steers having increased (P = 0.002) SUN concentration compared to SG sired steers, in addition to a treatment effect (P < 0.0001), with CON steers having a higher (P < 0.0001) SUN concentration than MI and HI steers, regardless of breed. The MI implant protocol increased net return per head, on average, by $97.28, regardless of breed, while the HI implant protocol increased net return by only $80.84. Taken together, despite the cattle breed types responding differently to the different anabolic implant protocols at times, a moderate intensity anabolic implant protocol was optimal in this experiment for steers raised in a temperate climate.
Asunto(s)
Dieta , Temperamento , Animales , Bovinos/genética , Alimentación Animal/análisis , Nitrógeno de la Urea Sanguínea , Composición Corporal , Dieta/veterinaria , Conducta AlimentariaRESUMEN
1. Increasingly, ecologists conceptualize local communities as connected to a regional species pool rather than as isolated entities. By this paradigm, community structure is determined through the relative strengths of dispersal-driven regional effects and local environmental factors. However, despite explicit incorporation of dispersal, metacommunity models and frameworks often fail to capture the realities of natural systems by not accounting for the configuration of space within which organisms disperse. This shortcoming may be of particular consequence in riverine networks which consist of linearly -arranged, hierarchical, branching habitat elements. Our goal was to understand how constraints of network connectivity in riverine systems change the relative importance of local vs. regional factors in structuring communities. 2. We hypothesized that communities in more isolated headwaters of riverine networks would be structured by local forces, while mainstem sections would be structured by both local and regional processes. We examined these hypotheses using a spatially explicit regional analysis of riverine macroinvertebrate communities, focusing on change in community similarity with distance between local communities [i.e., distance-decay relationships; (DDRs)], and the change in environmental similarity with distance. Strong DDRs frequently indicate dispersal-driven dynamics. 3. There was no evidence of a DDR in headwater communities, supporting our hypothesis that dispersal is a weak structuring force. Furthermore, a positive relationship between community similarity and environmental similarity supported dynamics driven by local environmental factors (i.e., species sorting). In mainstem habitats, significant DDRs and community x environment similarity relationships suggested both dispersal-driven and environmental constraints on local community structure (i.e., mass effects). 4. We used species traits to compare communities characterized by low vs. high dispersal taxa. In headwaters, neither strength nor mode (in-network vs. out of network) of dispersal changed our results. However, outcomes in mainstems changed substantially with both dispersal mode and strength, further supporting the hypothesis that regional forces drive community dynamics in mainstems. 5. Our findings demonstrate that the balance of local and regional effects changes depending on location within riverine network with local (environmental) factors dictating community structure in headwaters, and regional (dispersal driven) forces dominating in mainstems.
Asunto(s)
Ecosistema , Modelos Biológicos , Ríos , Animales , Ambiente , Análisis de Componente Principal , Conducta Espacial , Agua/química , Movimientos del AguaRESUMEN
The N-terminal sequence of a novel sheep-derived peptide with growth inhibitory activity has been obtained. The N-terminal fragment was chemically synthesised and designated EPL001. The kidney was chosen as the first mammalian system in which to study EPL001 since kidney growth can be accurately quantified following a surgical reduction in renal mass. Cell proliferation was measured in mouse collecting duct kidney (MCDK) cells stimulated with insulin-like growth factor I (IGF-I). Compensatory renal growth (CRG) was induced in Wistar rats and either EPL001 or an EPL001 antibody delivered by continuous renal tissue infusion. Mouse monoclonal antibodies to EPL001 were generated for immunoneutralisation, rabbit polyclonal antibodies were generated for immunohistochemistry. EPL001 had no apparent effect on IGF-I stimulated cell proliferation in MCDK cells in vitro, yet provoked a dose-dependent inhibition of CRG in vivo. An EPL001 antibody potentiated CRG, in the absence of exogenous EPL001, consistent with an inhibitory role in kidney growth for an endogenous peptide containing the EPL001 sequence. Tubular staining for epitopes to the EPL001 sequence was detected in normal human kidney sections and enhanced in renal cell carcinoma. Results support the presence of growth inhibitory activity in the N-terminus of a sheep-derived peptide with evidence for both its presence and endogenous activity in the kidney. Attempts to further characterise its structure and activity are ongoing.
Asunto(s)
Riñón/crecimiento & desarrollo , Oligopéptidos/farmacología , Péptidos/farmacología , Secuencia de Aminoácidos , Animales , Humanos , Factor I del Crecimiento Similar a la Insulina/metabolismo , Riñón/efectos de los fármacos , Riñón/metabolismo , Ratones , Ratas , Ovinos/metabolismoRESUMEN
BACKGROUND AND PURPOSE: Selection of the correct flow-diverter size is critical for cerebral aneurysm treatment success, but it remains challenging due to the interplay of device size, anatomy, and deployment. Current convention does not address these challenges well. The goals of this pilot study were to determine whether computational modeling improves flow-diverter sizing over current convention and to validate simulated deployments. MATERIALS AND METHODS: Seven experienced neurosurgeons and interventional neuroradiologists used computational modeling to prospectively plan 19 clinical interventions. In each patient case, physicians simulated 2-4 flow-diverter sizes that were under consideration based on preprocedural imaging. In addition, physicians identified a preferred device size using the current convention. A questionnaire on the impact of computational modeling on the procedure was completed immediately after treatment. Rotational angiography image data were acquired after treatment and compared with flow-diverter simulations to validate the output of the software platform. RESULTS: According to questionnaire responses, physicians found the simulations useful for treatment planning, and they increased their confidence in device selection in 94.7% of cases. After viewing the simulations results, physicians selected a device size that was different from the original conventionally planned device size in 63.2% of cases. The average absolute difference between clinical and simulated flow-diverter lengths was 2.1 mm. In 57% of cases, average simulated flow-diverter diameters were within the measurement uncertainty of clinical flow-diverter diameters. CONCLUSIONS: Physicians found computational modeling to be an impactful and useful tool for flow-diverter treatment planning. Validation results showed good agreement between simulated and clinical flow-diverter diameters and lengths.
Asunto(s)
Implantación de Prótesis Vascular/métodos , Prótesis Vascular , Simulación por Computador , Aneurisma Intracraneal/cirugía , Femenino , Humanos , Masculino , Proyectos Piloto , Programas InformáticosRESUMEN
Event-related potentials (ERPs) are a physiological measure of cognitive function that have shown diagnostic and prognostic utility in Alzheimer's disease (AD). In this study, we used a novel eigenvector-based technique to better understand brain electrophysiological differences between subjects with mild AD and healthy controls (HC). Using ERPs from 75 subjects with mild AD and 95 HC, we first calculated cognitive task eigenvectors within each subject from three conditions and then calculated second-order eigenvector components to compare the AD group to the HC group. A MANOVA of the three second-level components discriminated between AD and HC multivariately (Wilks' lambda=.4297, p<0.0001, R2 = .5703), and also on each of the three components univariately (all 3 p-values<0.0001). The eigenvector-based technique used in this study accurately discriminated between the mild AD group and HC. As such, this analysis method adds to our understanding of the differences in ERP signal between AD and HC, and could provide a sensitive biomarker for diagnosis and monitoring of AD progression.
RESUMEN
In this study we have investigated the requirement for phosphoinositide metabolism, diradylglycerol (DG) production and protein kinase C (PKC) activation in recombinant basic fibroblast growth factor (rbFGF)-mediated reinitiation of DNA synthesis in Swiss 3T3 cells. We have assessed the involvement of PKC activation in rbFGF-induced DNA synthesis by two approaches; enzymic inhibition by H7 and down-regulation by prolonged phorbol-ester treatment. In both conditions we observed that rbFGF was able to sustain a significant component of its mitogenic response, therefore denying an exclusive role for the activation of downregulatable and H7-sensitive PKC isoforms in rbFGF-induced reinitiation of DNA synthesis. Moreover, we have found no evidence for diacylglycerol accumulation in response to rbFGF by 3T3 cells. In previous studies, we observed that rbFGF caused a moderate and slow accumulation of total inositol phosphates. This effect was significant only after a 60 min incubation. It is our contention that rbFGF, in our culture system, does not exert a direct effect on phosphoinositide metabolism.
Asunto(s)
Diglicéridos/biosíntesis , Regulación hacia Abajo , Factor 2 de Crecimiento de Fibroblastos/farmacología , Mitógenos/farmacología , Proteína Quinasa C/metabolismo , 1-(5-Isoquinolinesulfonil)-2-Metilpiperazina , Células 3T3 , Animales , Replicación del ADN/efectos de los fármacos , Activación Enzimática , Isoquinolinas/farmacología , Ratones , Piperazinas/farmacología , Proteína Quinasa C/antagonistas & inhibidores , Proteínas Recombinantes/farmacología , Acetato de Tetradecanoilforbol/farmacologíaRESUMEN
In this study we have attempted to characterize the mechanism of recombinant bovine basic fibroblast growth factor (rbFGF)-induced release of arachidonic acid from prelabelled Swiss 3T3 fibroblasts. Recombinant bFGF caused the release of [3H]arachidonic acid from metabolically labelled cells in a dose- and time-dependent manner. This effect was maximal with 10 ng rbFGF/ml and became significant after a 30-min incubation. Although rbFGF was able to cause a modest increase in total inositol phosphate accumulation, an examination of the time-course of the latter effect revealed that enhanced [3H]arachidonic-acid release could not have been derived from phosphoinositide metabolism. Evidence suggesting that rbFGF-induced release of [3H]arachidonic acid was being mediated via a PLA2 pathway was obtained by pharmacological antagonism using mepacrine, a putative PLA2 inhibitor. Moreover, treatment of cells with neomycin failed to attenuate rbFGF-mediated release of [3H]arachidonic acid. Chelation of extracellular calcium by EGTA was found to abrogate rbFGF-induced liberation of [3H]arachidonic add. Down-regulation of protein kinase C (PKC) by prolonged treatment of cells with the phorbol ester, PMA, was observed to have no effect on the action of rbFGF on [3H]arachidonic add release from Swiss 3T3 fibroblasts. While rbFGF was found to cause the indomethacin-sensitive production of prostaglandin E2 (PGE2) in a dose-dependent manner, this effect was independent of rbFGF-induced reinitiation of DNA synthesis. Clearly, the effect of rbFGF on cellular DNA synthesis was being mediated independently of PGE2 biosynthesis. We discuss the potential importance of the PLA2-signalling pathway in the mechanism of action of fibroblast growth factors.
Asunto(s)
Ácido Araquidónico/metabolismo , Factor 2 de Crecimiento de Fibroblastos/farmacología , Fosfatidilinositoles/metabolismo , Células 3T3/efectos de los fármacos , Animales , ADN/biosíntesis , Dinoprostona/biosíntesis , Ratones , Neomicina/farmacología , Quinacrina/farmacología , Proteínas Recombinantes/farmacología , Factores de Tiempo , TritioRESUMEN
Acetylcholine, oxotremorine and carbachol, compounds that exhibit muscarinic agonist activity, maximally inhibited basal prolactin secretion from GH3 cells by approx. 50% and intracellular cyclic AMP levels by approx. 20%. Both parameters were inhibited with similar potencies by each agonist. These inhibitory effects were blocked by a muscarinic but not by a nicotinic receptor antagonist. In the presence of VIP or IBMX, which raise intracellular cyclic AMP levels and stimulate hormone release, the degree of muscarinic inhibition was increased, but the potency remained unchanged. Similar changes in the secretory rate of prolactin and growth hormone occurred in these and in cell perifusion experiments. These results suggest that the inhibition of hormone secretion from GH3 cells by muscarinic agonists is mediated by a decrease in intracellular cyclic AMP levels.
Asunto(s)
AMP Cíclico/metabolismo , Hormona del Crecimiento/metabolismo , Neoplasias Hipofisarias/metabolismo , Prolactina/metabolismo , Receptores Muscarínicos/metabolismo , 1-Metil-3-Isobutilxantina/farmacología , Acetilcolina/farmacología , Animales , Carbacol/farmacología , Línea Celular , Cinética , Oxotremorina/farmacología , Adenohipófisis/fisiopatología , Ratas , Receptores Muscarínicos/efectos de los fármacos , Péptido Intestinal Vasoactivo/farmacologíaRESUMEN
We have reported previously that tumour-promoting phorbol esters modulate both basal and vasoactive intestinal polypeptide (VIP)-stimulated adenylyl cyclase activity in GH3 (an established pituitary cell line). Here, we probe the receptor and cell specificity of this response. Experiments were performed in the presence of isobutylmethylxanthine. Unlike the response in GH3 cells, the tumour-promoting phorbol ester (tetradecanoyl phorbol acetate (TPA] did not affect either basal adenylyl cyclase activity nor VIP-stimulated activity in the rat osteosarcoma subclones UMR 106-01 and UMR 106-06. In addition, the cyclase responses to parathyroid hormone (PTH), and, in the case of UMR 106-06, to calcitonin were unaffected by tumour-promoting phorbol ester. However, prostaglandin E2-stimulated cyclase activity in both of these subclones was attenuated in a dose-dependent manner.
Asunto(s)
Adenilil Ciclasas/metabolismo , Dinoprostona/farmacología , Osteosarcoma/enzimología , Proteína Quinasa C/metabolismo , Transducción de Señal/efectos de los fármacos , Animales , Bovinos , Dinoprostona/administración & dosificación , Osteosarcoma/tratamiento farmacológico , Ratas , Salmón , Acetato de Tetradecanoilforbol/farmacología , Células Tumorales Cultivadas , Péptido Intestinal Vasoactivo/farmacologíaRESUMEN
The effect of bradykinin (BK) on proteinase activity, prostaglandin synthesis, and the production of interleukin-6 (IL-6) was investigated in cultures of human osteoblast-like cells. Bradykinin had no effect on stromelysin activity and plasminogen activator activity produced by human osteoblast-like cells. However, BK stimulated the production of prostaglandin E2, an effect that was markedly enhanced by pre-incubation with recombinant interleukin-1 alpha (rhIL-1 alpha), but was apparently unaffected by BK receptor antagonists types 1 and 2. Bradykinin stimulated the intracellular accumulation of total inositol phosphates suggesting that its effects were mediated by stimulation of phosphoinositide metabolism. Bradykinin within the dose range of 10(-11)-10(-5) M also significantly stimulated the production of IL-6. Bradykinin may, therefore, mediate a variety of responses in bone under both physiological and pathological conditions.
Asunto(s)
Bradiquinina/farmacología , Dinoprostona/biosíntesis , Interleucina-6/biosíntesis , Osteoblastos/metabolismo , Bradiquinina/análogos & derivados , Bradiquinina/antagonistas & inhibidores , Células Cultivadas , Relación Dosis-Respuesta a Droga , Ensayo de Inmunoadsorción Enzimática , Humanos , Fosfatos de Inositol/metabolismo , Cinética , Metaloproteinasa 3 de la Matriz , Metaloendopeptidasas/metabolismo , Osteoblastos/efectos de los fármacos , Transducción de SeñalRESUMEN
Although it is known that macrophages take up serotonin, a specific monoamine transporter has not been identified in macrophages. In this study, mRNA coding for the serotonin transporter (SERT) was detected with the reverse transcription-polymerase chain reaction (RT-PCR) in recruited mouse peritoneal macrophages. Sequencing confirmed the identity of the RT-PCR product to mouse SERT mRNA. SERT protein was detected by Western blotting. Macrophage activation with lipopolysaccharide had no effect on expression of SERT mRNA or protein. Consistent with expression of a functional SERT, specific uptake of (3)H-serotonin in macrophages was sodium dependent and inhibited by fluoxetine (IC(50) 6.9 nM) and desipramine (IC(50) 32 nM) but not by nisoxetine or reserpine.
Asunto(s)
Macrófagos Peritoneales/metabolismo , Glicoproteínas de Membrana/biosíntesis , Proteínas de Transporte de Membrana/biosíntesis , Proteínas del Tejido Nervioso/biosíntesis , Serotonina/metabolismo , Animales , Western Blotting , Células COS , Femenino , Lipopolisacáridos/farmacología , Activación de Macrófagos , Macrófagos Peritoneales/química , Macrófagos Peritoneales/inmunología , Glicoproteínas de Membrana/antagonistas & inhibidores , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/aislamiento & purificación , Moduladores del Transporte de Membrana , Proteínas de Transporte de Membrana/antagonistas & inhibidores , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/aislamiento & purificación , Ratones , Ratones Endogámicos CBA , Datos de Secuencia Molecular , Proteínas del Tejido Nervioso/antagonistas & inhibidores , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/aislamiento & purificación , ARN Mensajero/biosíntesis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Antagonistas de la Serotonina/farmacología , Proteínas de Transporte de Serotonina en la Membrana Plasmática , Tritio/metabolismoRESUMEN
In the present study we have shown that the cancer therapeutic drug, daunorubicin, induces apoptosis in the human lymphoblastic leukemia cell line Jurkat E6.1. This effect was both dose-and time-dependent with nuclear fragmentation detectable by 8 h. Caspases have been implicated in pro-apoptotic events. By utilizing synthetic fluorochrome-linked substrates of the caspases, we observed that a caspase-3-like enzyme had dramatically increased activity (3340 130% with respect to basal levels) in response to daunorubicin treatment. Furthermore, by using an inhibitor to caspase-3, Ac-DEVD-CHO, we have shown that activation of a caspase-3-like enzyme appears to be necessary for nuclear fragmentation and apoptotic body formation, but is not required for chromatin condensation. In contrast, a general caspase inhibitor, Z-VAD-fmk, inhibited all apoptotic parameters measured. Ceramide has been implicated in daunorubicin-induced apoptosis in human myeloid leukemia cells. However, in Jurkat cells, caspase activation does not appear to be a consequence of ceramide generation since, although ceramide levels were elevated through the action of ceramide synthase in response to daunorubicin treatment, this occurred with slower kinetics than either nuclear fragmentation or caspase activation. In contrast, caspase inhibitors abrogated ceramide elevation induced by DNR treatment, suggesting that ceramide synthase may be a downstream target for caspase action. Therefore, daunorubicin-induced apoptosis does not appear to be mediated by ceramide in the lymphoblastic leukemia cell line, Jurkat E6.1. Instead, caspase 3 activity appears to be necessary, but not sufficient for this process.
Asunto(s)
Antibióticos Antineoplásicos/uso terapéutico , Caspasas/metabolismo , Daunorrubicina/uso terapéutico , Precursores Enzimáticos/metabolismo , Leucemia de Células T/tratamiento farmacológico , Apoptosis/efectos de los fármacos , Caspasa 3 , Ceramidas/biosíntesis , Ensayos de Selección de Medicamentos Antitumorales , Activación Enzimática , Humanos , Células Jurkat , Leucemia de Células T/metabolismo , Oxidorreductasas/efectos de los fármacosRESUMEN
The effect of Mn2+ (a commonly used Ca2+ antagonist) on prolactin secretion from pituitary cells was investigated. In the presence of normal extracellular Ca2+ levels (2.5mM), Mn2+ inhibited basal, TRH- and K+- stimulated prolactin secretion. The Ca2+ ionophore, A23187, partially overcame the inhibitory effect of Mn2+. However, in the presence of low extracellular Ca2+ (less than 100 microM), which decreased basal prolactin secretion and abolished any stimulatory effects of TRH or K+, a paradoxical stimulatory effect was observed with Mn2+ in the presence of A23187. In the presence of Ca2+, Mn2+ appeared to be inhibitory due to its Ca2+ antagonistic effects, but at low Ca2+ levels, intracellular stimulatory effects of Mn2+ became apparent.
Asunto(s)
Manganeso/farmacología , Adenohipófisis/metabolismo , Prolactina/metabolismo , Animales , Calcimicina/farmacología , Calcio/farmacología , Masculino , Adenohipófisis/efectos de los fármacos , Potasio/farmacología , Ratas , Ratas Endogámicas , Hormona Liberadora de Tirotropina/farmacologíaRESUMEN
Bradykinin stimulated prolactin secretion from monolayer cultures of rat anterior pituitary cells, the stimulation being greater from the cells of male rats. This stimulated secretion was accompanied by a rise in total inositol phosphate accumulation, suggesting that the action of bradykinin is mediated by phosphoinositide hydrolysis. The increase in inositol phosphate accumulation was biphasic; a further sharp rise occurred when the concentration of bradykinin exceeded 1 mumol/l. This may indicate that bradykinin acts on other cell types in the pituitary gland. Bradykinin had no effect on growth hormone secretion from cells of normal pituitary glands, or on prolactin secretion and phosphoinositide metabolism in GH3 rat pituitary tumour cells. Bradykinin receptor antagonists (both B1 and B2) had no effect on either bradykinin-stimulated inositol phosphate accumulation or prolactin secretion. Kallikreins, the enzymes responsible for the generation of kinins, are known to be present in the adenohypophysis. Therefore, the results presented here would suggest that kinins may have a role as paracrine agents in the pituitary gland.
Asunto(s)
Bradiquinina/fisiología , Fosfatidilinositoles/metabolismo , Adenohipófisis/metabolismo , Prolactina/metabolismo , Animales , Bradiquinina/farmacología , Células Cultivadas , Femenino , Hormona del Crecimiento/metabolismo , Masculino , Adenohipófisis/citología , Ratas , Ratas Endogámicas , Receptores de Bradiquinina , Receptores de Neurotransmisores/metabolismoRESUMEN
Our previous studies indicated that PI3-kinase is involved in prolactin (PRL) signalling. We have now examined the involvement of the src tyrosine kinase, fyn, in PRL-induced the activation of PI3-kinase in the rat lymphoma cell line, Nb2. Cells were stimulated with increasing doses of PRL, lysed and immunoprecipitated with anti-fyn specific antibody. Then PI3-kinase activity was measured as the increase in the phosphorylation of phosphatidylinositol to phosphatidylinositol 3-phosphate separated by TLC. Our data indicated that, in PRL treated cells, co-precipitation of PI3-kinase with anti-fyn antiserum led to time and dose-dependent activation of PI3-kinase in vitro and that this activation was blocked by the addition of LY294002. However, LY294002 appeared to have no effect on fyn autophosphorylation. Furthermore, the physical association of PI3-kinase with fyn was confirmed by Western blot analysis employing the same specific antisera. These data provide evidence that PRL-induced activation of PI3-kinase may be mediated by the tyrosine phosphorylation of fyn in Nb2 cells.
Asunto(s)
Fosfatidilinositol 3-Quinasas/efectos de los fármacos , Prolactina/farmacología , Proteínas Proto-Oncogénicas/efectos de los fármacos , Proteínas Proto-Oncogénicas/metabolismo , Tirosina/metabolismo , Cromonas/farmacología , Cinamatos/farmacología , Relación Dosis-Respuesta a Droga , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Morfolinas/farmacología , Fosfatidilinositol 3-Quinasas/metabolismo , Inhibidores de las Quinasa Fosfoinosítidos-3 , Fosforilación/efectos de los fármacos , Pruebas de Precipitina , Prolactina/administración & dosificación , Proteínas Proto-Oncogénicas c-fyn , Factores de Tiempo , Células Tumorales Cultivadas , Tirosina/efectos de los fármacosRESUMEN
The mechanism of action of the cytokine, interleukin-1 (IL-1), has been investigated. Mouse thymoma (EL4 6.1) cells were preincubated with [3H]-glycerol and then incubated with recombinant IL-1 beta for varying periods. Interleukin-1 caused a rapid increase in diacylglycerol production (approx. 2 fold at 30 secs). This reproducible enhancement of diacylglycerol accumulation was abolished by pretreatment of the cells with pertussis toxin. Interestingly, a similar IL-1 induced increase in diacylglycerol was observed when the cells were preincubated with [3H]-myristic acid. These results appear to suggest a novel mode of action of interleukin-1 which involves a G-protein mediated breakdown of a membrane lipid resulting in the production of diacylglycerol. It is suggested that one possible candidate for this parent lipid may be a phosphatidylinositol glycan.
Asunto(s)
Diglicéridos/biosíntesis , Glicéridos/biosíntesis , Interleucina-1/farmacología , Toxina del Pertussis , Timoma/patología , Neoplasias del Timo/patología , Factores de Virulencia de Bordetella/farmacología , Animales , Regulación de la Expresión Génica/efectos de los fármacos , Ratones , Proteínas Recombinantes/farmacología , Transducción de Señal , Timoma/metabolismo , Neoplasias del Timo/metabolismo , Células Tumorales Cultivadas/efectos de los fármacos , Células Tumorales Cultivadas/metabolismoRESUMEN
The efficacy and safety of flurbiprofen (Ansaid, Upjohn), 100 mg twice daily, were compared with those of naproxen, 250 mg twice daily, in a six-week, double-blind, randomized study involving 133 patients with rheumatoid arthritis. Patients completing the six-week treatment phase were then treated with flurbiprofen, 100 mg twice daily, during a six-week open-label phase. In the double-blind phase, both treatment groups showed improvement from baseline and, in general, the arthritic condition of all patients was significantly less severe while receiving treatment. In the open-label phase, the patients in whom therapy was switched from naproxen to flurbiprofen reported greater improvement compared with baseline than they did at the end of the double-blind phase. Statistically significant differences between medication groups were few. At weeks four and six, grip strength for the naproxen group increased from baseline by a marginal amount compared with the flurbiprofen group. Global evaluations of disease improvement by patients and physicians and proximal interphalangeal joint size showed trends in favor of flurbiprofen. In the double-blind phase, 29.4 percent of flurbiprofen-treated patients (n = 20) and 23.1 percent of naproxen-treated patients (n = 15) experienced side effects, most of which were gastrointestinal in origin. In the open-label phase, 81.0 percent of the patients (n = 87) satisfactorily completed the six weeks of flurbiprofen treatment. Based on this study, 100 mg of flurbiprofen administered twice daily was as effective as 250 mg of naproxen twice daily in the treatment of rheumatoid arthritis.
Asunto(s)
Artritis Reumatoide/tratamiento farmacológico , Flurbiprofeno/uso terapéutico , Naproxeno/uso terapéutico , Propionatos/uso terapéutico , Adolescente , Adulto , Anciano , Ensayos Clínicos como Asunto , Método Doble Ciego , Evaluación de Medicamentos , Flurbiprofeno/efectos adversos , Humanos , Persona de Mediana Edad , Naproxeno/efectos adversos , Distribución AleatoriaRESUMEN
In this double-blind, randomized trial involving 143 patients with osteoarthritis of the hip and/or knee, the efficacy and safety of twice-daily dosing with flurbiprofen (Ansaid, Upjohn), which has a half-life of 5.5 hours, were compared with those of sulindac, which has a half-life of 7.8 hours. Patients were treated with flurbiprofen (50 mg orally twice a day) or sulindac (150 mg orally twice a day) for six weeks. Based on evaluations by both patients and physicians, there were no statistically significant differences between the two treatment groups in most of the efficacy parameters studied. In addition, there were no statistically significant differences between the two treatment groups in the incidence or type of side effects, which were primarily gastrointestinal in origin. This study indicates that flurbiprofen, taken as 50 mg twice daily, is equally as effective as 150 mg of sulindac twice a day in the treatment of osteoarthritis.