RESUMEN
AIMS: The middle-out perspective (MOP) provides a lens to examine how actors positioned between government (top) and individuals (bottom) act to promote broader societal changes from the middle-out (rather than the top-down or bottom-up). The MOP has been used in recent years in the fields of energy, climate change, and development studies. We argue that public health practitioners involved with advocacy activities and creating alliances to amplify health promotion actions will be familiar with the general MOP concept if not the formal name. The article aims to demonstrate this argument. METHODS: This article introduces the MOP conceptual framework and customises it for a public health audience by positioning it among existing concepts and theories for actions within public health. Using two UK case studies (increasing signalised crossing times for pedestrians and the campaign for smoke-free legislation), we illustrate who middle actors are and what they can do to result in better public health outcomes. RESULTS: These case studies show that involving a wider range of middle actors, including those not traditionally involved in improving the public's health, can broaden the range and reach of organisations and individuals involving in advocating for public health measures. They also demonstrate that middle actors are not neutral. They can be recruited to improve public health outcomes, but they may also be exploited by commercial interests to block healthy policies or even promote a health-diminishing agenda. CONCLUSION: Using the MOP as a formal approach can help public health organisations and practitioners consider potential 'allies' from outside traditional health-related bodies or professions. Formal mapping can expand the range of who are considered potential middle actors for a particular public health issue. By applying the MOP, public health organisations and staff can enlist the additional leverage that is brought to bear by involving additional middle actors in improving the public's health.
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BACKGROUND: Post-coercion review has been increasingly regarded as a useful intervention in psychiatric inpatient setting. However, little is known about its effect on perceived coercion. METHODS: A multicenter, two-armed, randomized controlled trial was conducted, aiming at analyzing the effect of post-coercion review on perceived coercion. People with severe mental disorders, who experienced at least one coercive measure during inpatient treatment, were randomized using Zelen's design to an intervention group receiving standardized post-coercion review, or a control group treated as usual. The MacArthur admission experience scale (AES) and the coercion ladder (CL) were used to assess perceived coercion during inpatient treatment. The coercion experience scale (CES) measured experienced coercion during the coercive intervention. Analyses of covariance were performed to determine group differences. RESULTS: Of 422 randomized participants, n = 109 consented to participate in the trial. A restricted intention-to-treat analysis of all individuals who consented revealed no significant effect of the intervention on perceived coercion. A significant interaction effect between the factors gender and intervention on the AES scores was found. Sensitivity analysis revealed significant effects of the intervention on both AES and CL scores and an interaction effect between intervention and gender, indicating a higher efficacy in women. No effect of the intervention on CES scores was found. CONCLUSIONS: Standardized post-coercion review sessions did not alleviate the subjective perception of coercion in the total sample. However, post hoc analysis revealed a significant effect of the intervention in women. Results indicate the need to further address gender-specific issues related to coercion.
Asunto(s)
Coerción , Trastornos Mentales , Femenino , Hospitalización , HumanosRESUMEN
As a contribution towards detecting the genetic effects of low doses of genotoxic physical agents, this paper deals with the consequences of low-dose X-rays in the Aspergillus nidulans genome. The irradiation doses studied were those commonly used in dental clinics (1-5 cGy). Even very low doses promoted increased mitotic crossing-over frequencies in diploid strains heterozygous for several genetic markers including the ones involved in DNA repair and recombination mechanisms. Genetic markers of several heterozygous strains were individually analyzed disclosing that some markers were especially sensitive to the treatments. These markers should be chosen as bio-indicators in the homozygotization index assay to better detect the recombinogenic/carcinogenic genomic effects of low-dose X-rays.
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Aspergillus nidulans/efectos de la radiación , Intercambio Genético/efectos de la radiación , Mitosis/efectos de la radiación , Rayos X , Aspergillus nidulans/genética , Intercambio Genético/genética , Daño del ADN , Diploidia , Relación Dosis-Respuesta en la Radiación , Homocigoto , Mitosis/genética , Pruebas de MutagenicidadRESUMEN
As a contribution towards detecting the genetic effects of low doses of genotoxic physical agents, this paper deals with the consequences of low-dose X-rays in the Aspergillus nidulans genome. The irradiation doses studied were those commonly used in dental clinics (1-5 cGy). Even very low doses promoted increased mitotic crossing-over frequencies in diploid strains heterozygous for several genetic markers including the ones involved in DNA repair and recombination mechanisms. Genetic markers of several heterozygous strains were individually analyzed disclosing that some markers were especially sensitive to the treatments. These markers should be chosen as bio-indicators in the homozygotization index assay to better detect the recombinogenic/carcinogenic genomic effects of low-dose X-rays.
Asunto(s)
Aspergillus nidulans/efectos de la radiación , Mitosis/efectos de la radiación , Intercambio Genético/efectos de la radiación , Rayos X , Aspergillus nidulans/genética , Diploidia , Daño del ADN , Homocigoto , Pruebas de Mutagenicidad , Mitosis/genética , Relación Dosis-Respuesta en la Radiación , Intercambio Genético/genéticaRESUMEN
Functional performance evaluations and intervention planning for children and youth is informed by comparisons of their performance to normative standards. The literature contains little data regarding the developmental norms for children on pinch strength. A random sample of 414 children was assessed on three separate measures of pinch strength. Pad-to-pad, three-jaw chuck, and lateral pinch were evaluated using the B & L Engineering pinch gauge while utilizing the standard positioning recommended by the American Society of Hand Therapists. The results were divided into distinct categories for 5-to 12-year-olds. The resulting normative data provide standards for pinch strength in children to be used in the clinical setting.
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Dedos/fisiología , Fuerza de la Mano , Destreza Motora , Factores de Edad , Niño , Preescolar , Femenino , Humanos , Indiana/epidemiología , Masculino , Estándares de Referencia , Valores de Referencia , MuestreoRESUMEN
The modification of the col shape and position by the restorative alveolar interface technique (RAI) was studied in the interproximal areas between the mandibular first molars and fourth premolars of 10 dogs. Full thickness flaps were raised to expose the interproximal root surface and alveolar bone crest. The RAI procedure was performed only on the experimental sides and the control areas were the opposite side of the same animal. The animals were sacrificed at zero hour, 7, 14, 21 and 28 days for histological analyses. Approximately 6.0-micron-thick sections were made in buccolingual and mesiodistal directions and stained with hematoxylin-eosin and Mallory for light microscopy analysis. A satisfactory healing process was observed up to the 14th and 21st days which showed a modified col shape. At this time, an inflammatory reaction developed affecting the evolution of the healing. The surgery had probably created conditions for the installation of an inflammatory process resulting from the modified anatomy of the interdental area.
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Restauración Dental Permanente/métodos , Inserción Epitelial/anatomía & histología , Inserción Epitelial/cirugía , Encía/cirugía , Proceso Alveolar/cirugía , Animales , Restauración Dental Permanente/efectos adversos , Perros , Gingivitis/etiología , Masculino , Estadísticas no Paramétricas , Cuello del Diente/cirugíaRESUMEN
To facilitate studies of the molecular determinants of host-meningococcal lipooligosaccharide (endotoxin) interactions at patho-physiologically relevant endotoxin concentrations (i.e. < or =10 ng/ml), we have generated acetate auxotrophs NMBACE1 from encapsulated Neisseria meningitidis (serogroup B, strain NMB) and NMBACE2 from an isogenic bacterial mutant lacking the polysialic acid capsule. Growth of the auxotrophs in medium containing [(14)C]acetate yielded (14)C-lipooligosaccharides containing approximately 600 cpm/ng. Gel sieving resolved 14C-lipooligosaccharide-containing aggregates with an estimated molecular mass of > or =20 x 10(6) Da (peak A) and approximately 1 x 10(6) Da (peak B) from both strains. Lipooligosaccharides in peaks A and B had the same fatty acid composition and SDS-polyacrylamide gel electrophoresis profile. 14C-Labeled capsule copurified with (14)C-lipooligosaccharides in peak B from NMBACE1, whereas the other aggregates contained only 14C-lipooligosaccharide. For all aggregates, lipopolysaccharide-binding protein and soluble CD14-induced delivery of lipooligosaccharides to endothelial cells and cell activation correlated with disaggregation of lipooligosaccharides. These processes were inhibited by the presence of capsule but unaffected by the size of the aggregates. In contrast, endotoxin activation of cells containing membrane CD14 was unaffected by capsule but diminished when endotoxin was presented in larger aggregates. These findings demonstrate that the physical presentation of lipooligosaccharide, including possible interactions with capsule, affect the ability of meningococcal endotoxin to interact with and activate specific host targets.
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Acetatos/metabolismo , Proteínas de Fase Aguda , Toxinas Bacterianas/metabolismo , Endotoxinas/metabolismo , Lipopolisacáridos/metabolismo , Glicoproteínas de Membrana , Neisseria meningitidis/patogenicidad , Cápsulas Bacterianas , Toxinas Bacterianas/química , Radioisótopos de Carbono , Proteínas Portadoras/metabolismo , Células Cultivadas , Endotelio Vascular/citología , Endotelio Vascular/metabolismo , Endotoxinas/química , Ácidos Grasos/análisis , Leucocitos/citología , Leucocitos/metabolismo , Receptores de Lipopolisacáridos/metabolismo , Lipopolisacáridos/química , Modelos Biológicos , Neisseria meningitidis/genética , Neisseria meningitidis/metabolismoRESUMEN
BACKGROUND: Vascularitis is a well-known extrahepatic manifestation of chronic hepatitis C. Mixed cryoglobulinemia is the most common form. To our knowledge, the present case is the first report associating chronic hepatitis C and temporal arteritis. CASE REPORT: A 56-year-old man with chronic hepatitis C in the precirrhogenic phase presented with fever and weight loss. The patient complained of pain of the scapular and pelvic girdles and headache and physical examination revealed claudication of the jaw and abolition of the upper limb pulses. Biopsy of the temporal artery confirmed the diagnosis of Horton's disease. The patient also had bilateral stenosis of the sub-clavian arteries. DISCUSSION: This observation of Horton's disease involving large vessels in a patient with chronic hepatitis C suggests that an infectious factor might trigger vascularitis.
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Arteritis de Células Gigantes/diagnóstico , Hepatitis C Crónica/complicaciones , Corticoesteroides/uso terapéutico , Antivirales/uso terapéutico , Arteriopatías Oclusivas/complicaciones , Quimioterapia Combinada , Femenino , Arteritis de Células Gigantes/tratamiento farmacológico , Arteritis de Células Gigantes/etiología , Hepatitis C Crónica/tratamiento farmacológico , Humanos , Interferón-alfa/uso terapéutico , Masculino , Persona de Mediana Edad , Radiografía , Ribavirina/uso terapéutico , Arterias Temporales/diagnóstico por imagen , Arterias Temporales/patologíaRESUMEN
Epoxyeicosatrienoic acids (EETs) are cytochrome P450-derived metabolites of arachidonic acid. They are potent endogenous vasodilator compounds produced by vascular cells, and EET-induced vasodilation has been attributed to activation of vascular smooth muscle cell (SMC) K(+) channels. However, in some cells, EETs activate Ca(2+) channels, resulting in Ca(2+) influx and increased intracellular Ca(2+) concentration ([Ca(2+)](i)). We investigated whether EETs also can activate Ca(2+) channels in vascular SMC and whether the resultant Ca(2+) influx can influence vascular tone. The 4 EET regioisomers (1 micromol/L) increased porcine aortic SMC [Ca(2+)](i) by 52% to 81%, whereas arachidonic acid, dihydroxyeicosatrienoic acids, and 15-hydroxyeicosatetraenoic acid (1 micromol/L) produced little effect. The increases in [Ca(2+)](i) produced by 14,15-EET were abolished by removal of extracellular Ca(2+) and by pretreatment with verapamil (10 micromol/L), an inhibitor of voltage-dependent (L-type) Ca(2+) channels. 14,15-EET did not alter Ca(2+) signaling induced by norepinephrine and thapsigargin. When administered to porcine coronary artery rings precontracted with a thromboxane mimetic, 14,15-EET produced relaxation. However, when administered to rings precontracted with acetylcholine or KCl, 14,15-EET produced additional contractions. In rings exposed to 10 mmol/L KCl, a concentration that did not affect resting ring tension, 14,15-EET produced small contractions that were abolished by EGTA (3 mmol/L) or verapamil (10 micromol/L). These observations indicate that 14,15-EET enhances [Ca(2+)](i) influx in vascular SMC through voltage-dependent Ca(2+) channels. This 14,15-EET-induced increase in [Ca(i)(2+)] can produce vasoconstriction and therefore may act to modulate EET-induced vasorelaxation.
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Ácido 8,11,14-Eicosatrienoico/metabolismo , Calcio/metabolismo , Líquido Intracelular/metabolismo , Músculo Liso Vascular/metabolismo , Ácido 8,11,14-Eicosatrienoico/análogos & derivados , Ácido 8,11,14-Eicosatrienoico/farmacología , Animales , Aorta Torácica/citología , Aorta Torácica/efectos de los fármacos , Bloqueadores de los Canales de Calcio/farmacología , Permeabilidad de la Membrana Celular/efectos de los fármacos , Permeabilidad de la Membrana Celular/fisiología , Células Cultivadas , Quelantes/farmacología , Vasos Coronarios/efectos de los fármacos , Vasos Coronarios/metabolismo , Relación Dosis-Respuesta a Droga , Técnicas In Vitro , Líquido Intracelular/efectos de los fármacos , Contracción Muscular/efectos de los fármacos , Contracción Muscular/fisiología , Músculo Liso Vascular/citología , Músculo Liso Vascular/efectos de los fármacos , Relación Estructura-Actividad , Porcinos , Vasoconstrictores/farmacología , Vasodilatadores/farmacologíaRESUMEN
14,15-Epoxyeicosatrienoic acid (EET), a cytochrome P-450 epoxygenase product of arachidonic acid (AA), reduced PGE2 formation by 40-75% in porcine aortic and murine brain microvascular smooth muscle cells. The inhibition was reversed 6-10 h after removal of 14,15-EET from the medium and was regioisomeric specific; 8,9-EET produced a smaller effect, whereas 11,12- and 5,6-EET were ineffective. Although the cells converted 14,15-EET to 14, 15-dihydroxyeicosatrienoic acid (14,15-DHET), 14,15-DHET did not inhibit PGE2 formation, and the 14,15-EET-induced inhibition was potentiated by 4-phenylchalcone oxide, an epoxide hydrolase inhibitor. The inhibition occurred when substrate amounts of AA were used and was not accompanied by enhanced production of other PGs, suggesting an effect on PGH synthase; however, in murine cells, 14, 15-EET did not reduce PGH synthase mRNA or protein. Moreover, the 14, 15-EET-induced decrease in PGE2 production was overcome by increasing the concentration of AA, but not oleic acid (which is not a substrate for PGH synthase). These findings suggest that 14,15-EET competitively inhibits PGH synthase activity in vascular smooth muscle cells. The 14,15-EET-induced inhibition of PGE2 production resulted in potentiation of platelet-derived growth factor-induced smooth muscle cell proliferation, suggesting that the competitive inhibition of PGH synthase by 14,15-EET can affect growth responses in smooth muscle cells.
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Ácido 8,11,14-Eicosatrienoico/análogos & derivados , Dinoprostona/antagonistas & inhibidores , Músculo Liso Vascular/efectos de los fármacos , Músculo Liso Vascular/metabolismo , Ácido 8,11,14-Eicosatrienoico/farmacología , Animales , Aorta/citología , Aorta/efectos de los fármacos , Aorta/metabolismo , División Celular/efectos de los fármacos , Células Cultivadas , Circulación Cerebrovascular/fisiología , Ácidos Hidroxieicosatetraenoicos/farmacología , Microcirculación/fisiología , Músculo Liso Vascular/citología , Factor de Crecimiento Derivado de Plaquetas/farmacología , PorcinosRESUMEN
Pseudomonas aeruginosa, an opportunistic human pathogen, causes acute pneumonia in patients with hospital-acquired infections and is commonly associated with chronic lung disease in individuals with cystic fibrosis (CF). Evidence suggests that the pathophysiological effects of P. aeruginosa are mediated in part by virulence factors secreted by the bacterium. Among these factors is pyocyanin, a redox active compound that increases intracellular oxidant stress. We find that pyocyanin increases release of interleukin-8 (IL-8) by both normal and CF airway epithelial cell lines and by primary airway epithelial cells. Moreover, pyocyanin synergizes with the inflammatory cytokines tumor necrosis factor alpha and IL-1alpha. RNase protection assays indicate that increased IL-8 release is accompanied by increased levels of IL-8 mRNA. The antioxidant n-acetyl cysteine, general inhibitors of protein tyrosine kinases, and specific inhibitors of mitogen-activated protein kinases diminish pyocyanin-dependent increases in IL-8 release. Conversely, inhibitors of protein kinases C (PKC) and PKA have no effect. In contrast to its effects on IL-8 expression, pyocyanin inhibits cytokine-dependent expression of the monocyte/macrophage/T-cell chemokine RANTES. Increased release of IL-8, a potent neutrophil chemoattractant, in response to pyocyanin could contribute to the marked infiltration of neutrophils and subsequent neutrophil-mediated tissue damage that are observed in Pseudomonas-associated lung disease.
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Interleucina-8/biosíntesis , Pulmón/inmunología , Pseudomonas , Piocianina/farmacología , Acetilcisteína/farmacología , Antioxidantes/farmacología , Proteínas Quinasas Dependientes de Calcio-Calmodulina/antagonistas & inhibidores , Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Células Cultivadas , Quimiocina CCL5/biosíntesis , Sinergismo Farmacológico , Células Epiteliales/citología , Células Epiteliales/inmunología , Humanos , Interleucina-8/genética , Pulmón/citología , Oxidantes/metabolismo , Proteína Quinasa C/antagonistas & inhibidores , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Proteínas Tirosina Quinasas/metabolismo , ARN Mensajero/análisis , Transducción de Señal , Factor de Necrosis Tumoral alfa/biosíntesisRESUMEN
We examined the effects of the L- and D-isomers of S-nitroso-beta,beta-dimethylcysteine (L- and D-S-nitrosopenicillamine, 10(-7)-10(-5) M) on the guanosine 3',5'-cyclic monophosphate (cGMP) content of cultured porcine aortic smooth muscle cells and the decomposition of these stereoisomers to nitric oxide (NO). L-S-nitrosopenicillamine was a more potent generator of cGMP than D-S-nitrosopenicillamine although both stereoisomers equally decomposed to NO. The 10(-7) M concentration of L- or D-S-nitrosopenicillamine did not generate detectable amounts of NO although 10(-7) M L-S-nitrosopenicillamine but not D-S-nitrosopenicillamine generated significant amounts of cGMP. This study shows that the stereoisomeric configuration of S-nitrosopenicillamine is an important factor in its biological potency. The data suggest that the extracellular or intracellular generation of NO is not the only mechanism by which this S-nitrosothiol generates cGMP in vascular smooth muscle.
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Músculo Liso Vascular/efectos de los fármacos , Compuestos Nitrosos/farmacología , Penicilamina/análogos & derivados , Penicilamina/farmacología , Análisis de Varianza , Animales , Aorta/efectos de los fármacos , Aorta/metabolismo , Células Cultivadas , GMP Cíclico/análisis , GMP Cíclico/biosíntesis , Músculo Liso Vascular/metabolismo , Óxido Nítrico/metabolismo , Compuestos Nitrosos/metabolismo , Penicilamina/metabolismo , Estereoisomerismo , PorcinosRESUMEN
Madin-Darby canine kidney (MDCK) epithelial cells were grown in culture medium supplemented with 1% fetal bovine serum (FBS) to provide a cell culture model of essential fatty acid deficiency (EFAD). 5,8,11-Eicosatrienoic acid (20:3n-9) accumulated in cellular phospholipids, and arachidonic acid (20:4) decreased. A large increase in cellular cholesterol/phospholipid ratio was observed. Hemicyst formation was greatly reduced from normal levels in the EFAD-MDCK cells. Scanning and transmission electron microscopy revealed that EFAD-MDCK were much flatter than their normal counterparts. They had much less dense surface microvilli, mitochondria and other organelles were very sparse, except in the perinuclear area, and much of the peripheral cytoplasm was amorphous. The EFAD was rapidly reversed by the addition of as little as 10 microM linoleic or arachidonic acid to the medium. Cells supplemented with 10% FBS, the usual culture condition, displayed borderline EFAD, with intermediate levels of 20:3n-9 and 20:4 and hemicyst formation. These studies suggest that EFAD reduces water and electrolyte transport in renal tubular epithelium.
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Ácidos Grasos Esenciales/deficiencia , Riñón/fisiología , Riñón/ultraestructura , Ácido 8,11,14-Eicosatrienoico/análogos & derivados , Ácido 8,11,14-Eicosatrienoico/metabolismo , Animales , Ácido Araquidónico/metabolismo , Ácido Araquidónico/farmacología , Sangre , Línea Celular , Medios de Cultivo , Perros , Ácidos Grasos/administración & dosificación , Ácidos Grasos Esenciales/administración & dosificación , Ácido Linoleico , Ácidos Linoleicos/farmacología , Metabolismo de los Lípidos , Microscopía Electrónica , Microscopía Electrónica de Rastreo , Fosfolípidos/metabolismo , Fósforo/metabolismoRESUMEN
13-Hydroxyoctadecadienoic acid (HODE) (2 microM) consistently increased porcine aortic and pulmonary artery smooth muscle cell calcium concentrations ([Ca2+]i), whereas 9-HODE and linoleic acid had no significant effect in the aortic cells and a much lesser effect in the pulmonary artery cells. A transient increase in [Ca2+]i occurred with as little as 50 nM 13-HODE. Structural specificity for elevation of [Ca2+]i also was seen with the monohydroxyeicosatetraenoic acids (HETEs), with 12-HETE but not 5- or 15-HETE increasing [Ca2+]i. 13-HODE, but not 9-HODE, increased smooth muscle cell guanosine 3',5'-cyclic monophosphate (cGMP) levels. The [Ca2+]i increase produced by 13-HODE was dependent on extracellular calcium and was inhibited by the calcium channel blockers verapamil and nifedipine and by KT-5823, a cGMP-dependent kinase inhibitor. A similar increase in [Ca2+]i was produced by 8-bromo-cGMP. These results suggest that 13-HODE, a 15-lipoxygenase product formed from linoleic acid, can act as a lipid mediator in vascular smooth muscle. It raises smooth muscle cGMP, causing a secondary increase in [Ca2+]i due to Ca2+ influx through a cGMP kinase-dependent L-type channel.
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Calcio/metabolismo , Membranas Intracelulares/metabolismo , Ácidos Linoleicos Conjugados , Ácidos Linoleicos/farmacología , Músculo Liso Vascular/metabolismo , Animales , Células Cultivadas , GMP Cíclico/metabolismo , Ácidos Hidroxieicosatetraenoicos/farmacología , Músculo Liso Vascular/citología , PorcinosRESUMEN
Platelet-activating factor (PAF) is a potent mediator which produces a wide range of biological responses by binding to specific, high affinity receptors on the target cell surface. In addition, we and others have observed cellular responses to PAF which are not receptor-mediated. We report here that in HBE-16 human bronchial epithelial cells, PAF produces a biphasic increase in [Ca2+]i consisting of a rapid initial increase due to release from intracellular stores followed by a gradual, sustained phase caused by influx of extracellular Ca2+. Under certain conditions, the PAF receptor antagonist L-659,989 completely blocks the release of Ca2+ from intracellular stores, suggesting a complete block of the receptor-mediated response. Under these same conditions, a residual influx of extracellular Ca2+ is observed, suggesting a possible receptor-independent response. HBE-16 cells partially metabolize PAF to 1-O-alkyl-2-acetyl-sn-glycerol (AAG), a bioactive diacylglycerol analog. Moreover, AAG stimulates Ca2+ influx in these cells; the response to AAG is at least 100-fold more potent than that to PAF. Taken together, these results suggest that PAF may stimulate Ca2+ influx in HBE-16 cells through a receptor-independent pathway mediated by AAG. Thus these studies suggest a previously unrecognized dual-pathway regulatory mechanism for PAF in the airway.
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Bronquios/metabolismo , Calcio/metabolismo , Éteres de Glicerilo/metabolismo , Factor de Activación Plaquetaria/farmacología , Glicoproteínas de Membrana Plaquetaria/fisiología , Receptores de Superficie Celular , Receptores Acoplados a Proteínas G , Bronquios/citología , Células Cultivadas , Epitelio/metabolismo , Furanos/farmacología , Humanos , Técnicas In Vitro , Factor de Activación Plaquetaria/metabolismo , Glicoproteínas de Membrana Plaquetaria/antagonistas & inhibidoresRESUMEN
Lysophosphatidylcholine (lyso-PC) is a vasoactive phospholipid present in oxidized low-density lipoprotein. We used a coculture model of the vascular wall to study its interaction with endothelial cells (EC) and vascular smooth muscle cells (SMC). Lyso-PC was taken up readily by SMC and gradually acylated to phosphatidylcholine. Low concentrations (< or = 1 microM) of lyso-PC present in the interstitial medium of an EC-SMC coculture system were taken up primarily by the SMC. Lyso-PC produced a rapid two- to three-fold increase in SMC guanosine 3',5'-cyclic monophosphate (cGMP) levels, reaching a maximum in 1 min. This increase was associated with decreased SMC proliferation and increased calcium influx. The increase in intracellular calcium was inhibited by verapamil and KT5823, a specific cGMP-dependent kinase inhibitor, while a similar increase was produced by the membrane-permeant cGMP analogue 8-bromoguanosine 3',5'-cyclic monophosphate. These studies suggest that SMC are the primary target for the biological effects of lyso-PC present in the vessel wall and that the responses are mediated by calcium influx, possibly due to opening of a verapamil-sensitive cGMP kinase-dependent channel.
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Calcio/metabolismo , Carbazoles , GMP Cíclico/análogos & derivados , Indoles , Lisofosfatidilcolinas/metabolismo , Lisofosfatidilcolinas/farmacología , Músculo Liso Vascular/metabolismo , Verapamilo/farmacología , Alcaloides/farmacología , Animales , Aorta Torácica/efectos de los fármacos , Aorta Torácica/metabolismo , Transporte Biológico , Células Cultivadas , GMP Cíclico/farmacología , GMP Cíclico/fisiología , Fura-2 , Cinética , Músculo Liso Vascular/efectos de los fármacos , Inhibidores de Proteínas Quinasas , Espectrometría de Fluorescencia , PorcinosRESUMEN
The centrally acting alpha 2-adrenoceptor agonist clonidine was used to assess the sensitivity of alpha 2-adrenergic neurotransmission in man, using receptor-binding studies and clonidine-induced growth hormone response. Neither acute (2 micrograms/kg body weight) nor subchronic (3 days, 2 x 150 micrograms/kg body weight) administration of clonidine affected platelet alpha 2-adrenoceptor number in humans as judged by 3H-yohimbine and 3H-UK-14,304 binding. The same treatment also did not modify central postsynaptic alpha 2-adrenoceptor function in the same individuals as assessed by clonidine-induced growth hormone responses. Similarly, subchronic (3 days, 500 micrograms/kg body weight, i.p.) or chronic (14 days, 500 micrograms/kg, i.p.) administration of clonidine to mice failed to change 3H-yohimbine or 3H-UK-14,304 binding sites in membranes prepared from frontal cortex. On the other hand, in vitro experiments using mouse frontal cortex or human platelet membranes showed pronounced reduction of 3H-UK-14,304 but not of 3H-yohimbine binding sites after incubation with several adrenoceptor agonists. The data indicate that acute and subchronic clonidine treatment may not change alpha 2-adrenoceptor sensitivity in humans or mice as assessed both at the functional and receptor level.
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Adaptación Fisiológica/fisiología , Clonidina/administración & dosificación , Receptores Adrenérgicos alfa/efectos de los fármacos , Adulto , Animales , Plaquetas/metabolismo , Encéfalo/metabolismo , Femenino , Hormona del Crecimiento/metabolismo , Humanos , Masculino , Ratones , Ratones Endogámicos , Ensayo de Unión Radioligante , Sensibilidad y EspecificidadRESUMEN
To better understand the vascular actions of lysophosphatidylcholine (lysoPC), we studied the interaction of [1-14C]palmitate-labeled lysoPC with bovine aortic endothelial cells. These cells took up lysoPC from media containing albumin, low-density lipoproteins (LDL), or acetyl-LDL. Uptake occurred faster than conversion to phosphatidylcholine (PC), leading to some lysoPC accumulation in endothelial lipids. Endothelial cell monolayers grown on micropore filters took up lysoPC from both apical and basolateral surfaces, preventing substantial amounts from passage across the endothelial monolayer. However, lysoPC present in the interstitial medium of an endothelial-smooth muscle coculture was incorporated primarily by the smooth muscle cells. Endothelial cells grown on filters released lysoPC into both the apical and basolateral medium in the presence of albumin or lipoproteins. Exposure to 50 microM lysoPC produced no evidence of endothelial cytotoxicity, but prostaglandin (PG)I2 production was reduced. These studies suggest that the endothelium can participate in the processing of circulating lysoPC and, through basolateral uptake, can facilitate the removal of lysoPC formed within the arterial wall. By decreasing PGI2 output, however, exposure to high concentrations of lysoPC may reduce the antithrombotic and vasodilator capacity of the endothelium.
Asunto(s)
Aorta/efectos de los fármacos , Endotelio Vascular/efectos de los fármacos , Lisofosfatidilcolinas/farmacología , Animales , Aorta/citología , Polaridad Celular , Células Cultivadas , Medios de Cultivo , Endotelio Vascular/citología , Endotelio Vascular/metabolismo , Lipoproteínas LDL/farmacología , Lisofosfatidilcolinas/farmacocinética , Músculo Liso Vascular/citología , Músculo Liso Vascular/metabolismoRESUMEN
The effect of several antineoplastic agents on vascular smooth muscle cell proliferation was studied in vitro. Both fluorouracil and cytarabine produced significant concentration-dependent inhibition of smooth muscle cell proliferation in cultured porcine pulmonary artery in vitro, while cyclophosphamide stimulated growth. For fluorouracil, inhibition was near maximal at a concentration of 13.0 microgram/mL and was seen with both coincubation and 2-hour preincubation of fluorouracil with quiescent cells. Fluorouracil is a promising agent for inhibition of intimal proliferation. Further work is warranted to determine its effect in vivo.
Asunto(s)
Angioplastia de Balón , Antineoplásicos/farmacología , Músculo Liso Vascular/citología , Animales , División Celular/efectos de los fármacos , Células Cultivadas , Constricción Patológica , Ciclofosfamida/farmacología , Citarabina/farmacología , Relación Dosis-Respuesta a Droga , Fluorouracilo/farmacología , Músculo Liso Vascular/efectos de los fármacos , Arteria Pulmonar/citología , Recurrencia , PorcinosRESUMEN
The effect of aging on muscarinic cholinergic receptor function in dissociated cell aggregates of the mouse brain was investigated using two biochemical models, i.e., carbachol-induced accumulation of inositol monophosphates and carbachol-induced desensitization of muscarinic cholinergic receptors as measured by the sequestration of specific 3H-N-methyl-scopolamine binding. While aging strongly reduced carbachol-induced inositol monophosphate accumulation, desensitization was not affected in the brains of aged animals. Chronic treatment of aged mice with the nootropic drug piracetam (500 mg/kg daily PO) significantly elevated the agonist-induced accumulation of inositol monophosphates possibly by increasing the available number of muscarinic cholinergic receptors not being in a desensitized state. The results support the hypothesis that nootropics like piracetam might act in part by restoring age-related deficits of central muscarinic cholinergic receptor function.