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1.
J Ment Health ; 30(4): 526-540, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32186223

RESUMEN

BACKGROUND: Electroconvulsive therapy (ECT) is a controversial treatment. Research has predominantly focused on clinician assessment of short-term efficacy and, occasionally, on participant experiences of the treatment itself. While service user accounts of the long-term impacts of ECT are reported, they are dispersed throughout the literature and typically tangential to studie's main foci. AIM: The aim of this study was to synthesise service-user accounts, within peer-reviewed literature, of long-term impacts of ECT in their daily lives. METHODS: A qualitative meta-synthesis was conducted. A systematic literature search identified qualitative articles meeting the inclusion criteria. Results sections of eligible papers were analysed thematically. RESULTS: From 16 eligible papers, the review identified 11 long-term impacts, four social influences and five strategies that people employed to navigate these long-term impacts. CONCLUSION: Limited research has examined long-term experiences of ECT from service-user perspectives. These lived experience perspectives are required to facilitate peer-to-peer learning and assist future service delivery to align with needs of people living with long-term ECT impacts.


Asunto(s)
Terapia Electroconvulsiva , Humanos , Investigación Cualitativa
3.
Child Care Health Dev ; 33(1): 52-8, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17181753

RESUMEN

BACKGROUND: Research has suggested that well siblings of children with chronic and life-threatening illnesses are at risk for negative outcomes and that parents' responses to the illnesses can influence the adaptation of well siblings. Yet, parents' efforts to look after well siblings in the context of illness are rarely considered in literature about sibling adaptation. The importance of attending to the needs of well siblings was a major theme to emerge from a qualitative analysis of the experiences of parents of adolescent girls with anorexia nervosa. METHODS: In-depth interviews were conducted with 24 parents of adolescent girls with anorexia and analysed using grounded theory method. RESULTS: The data indicated that parents viewed caring for well siblings in the context of anorexia as an important role and responsibility. Parents reported making conscious and active efforts to look after well siblings by: maintaining normality; compensating for changes to routines; protecting siblings; providing emotional support; and managing the consequences. CONCLUSIONS: This paper provides a picture of the actions parents take to help well siblings adapt to anorexia in the family. Further research is needed to develop and expand this understanding to families experiencing a wide range of chronic and life-threatening illnesses. The findings underline the importance of clinical attention and further research into the critical parental role of caring for well siblings.


Asunto(s)
Anorexia Nerviosa/psicología , Relaciones Familiares , Relaciones Padres-Hijo , Responsabilidad Parental/psicología , Hermanos/psicología , Adaptación Psicológica , Adolescente , Adulto , Niño , Enfermedad Crónica , Femenino , Humanos , Masculino
4.
Cephalalgia ; 22(4): 260-4, 2002 May.
Artículo en Inglés | MEDLINE | ID: mdl-12100087

RESUMEN

The purpose of this study was to use intravital microscopy to determine the effect of a selective adenosine A1 receptor agonist, GR79236 (1, 3 and 10 microg/kg i.v.), on neurogenic dural blood vessel dilation in anaesthetized rats. Vasodilation was evoked either by electrical stimulation of perivascular trigeminal nerves or by intravenous CGRP. GR79236 (1-10 microg/kg i.v.) caused a dose-dependent inhibition of neurogenic vasodilation, but had no significant effect on dural vasodilation caused by CGRP. GR79236 (1-3 microg/kg i.v.) had no effect on basal dural vessel diameter, but caused transient dose-dependant bradycardia and hypotension. Bradycardia was more prolonged following 10 microg/kg i.v. GR79236. Pre-treatment with the adenosine A1 receptor antagonist DPCPX (1 mg/kg i.v.) prevented the inhibitory effect of GR79236 (10 microg/kg i.v.) on neurogenic vasodilation as well as GR79236-induced bradycardia and hypotension. These data suggest that the inhibition of neurogenic vasodilation by GR79236 is mediated via the activation of prejunctional adenosine A1 receptors. Provided the systemic cardiovascular effects could be limited, such a mechanism may offer a novel approach to migraine therapy.


Asunto(s)
Adenosina/farmacología , Duramadre/irrigación sanguínea , Agonistas del Receptor Purinérgico P1 , Nervio Trigémino/efectos de los fármacos , Vasodilatación/efectos de los fármacos , Adenosina/análogos & derivados , Adenosina/toxicidad , Anestesia General , Animales , Presión Sanguínea/efectos de los fármacos , Bradicardia/inducido químicamente , Péptido Relacionado con Gen de Calcitonina/farmacología , Evaluación Preclínica de Medicamentos , Estimulación Eléctrica , Frecuencia Cardíaca/efectos de los fármacos , Hipotensión/inducido químicamente , Masculino , Antagonistas de Receptores Purinérgicos P1 , Ratas , Ratas Sprague-Dawley , Receptores Purinérgicos P1/fisiología , Nervio Trigémino/fisiología , Xantinas/farmacología
5.
J Med Chem ; 44(5): 681-93, 2001 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-11262079

RESUMEN

Utilizing a pharmacophoric model of binding of 3-(2-aminoethyl)indoles to 5HT(1B/1D) receptors, we identified the 3-aminocyclobutyl group as a potential ethylamine isostere. A novel multidimensional chemometric approach was used to predict the intrinsic activity (degree of agonism) at the receptor. A qualitative model for pharmacokinetic properties was then used to guide the synthesis toward molecules likely to have oral bioavailability in humans. A novel synthetic route to 3-(3-dimethylaminocyclobutyl)indoles was developed. Analogues showed generally lower intrinsic activity at 5HT(1B/1D) receptors than their ethylamine counterparts. 4-[3-(trans-3-Dimethylaminocyclobutyl)-1H-indol-5-ylmethyl]-(4S)-oxazolidin-2-one (4991W93, 1) was identified as a partial agonist against 5HT(1B/1D) receptors, with low intrinsic activity. This molecule also has significant activity against 5HT(1F) receptors but is selective over other 5HT receptors. In addition this compound was found to be an exceptionally potent inhibitor of electrically induced plasma extravasation. Compound 1 may have utility in the treatment and prophylaxis of migraine.


Asunto(s)
Permeabilidad Capilar/efectos de los fármacos , Indoles/síntesis química , Oxazoles/síntesis química , Receptores de Serotonina/efectos de los fármacos , Agonistas de Receptores de Serotonina/síntesis química , Vasoconstrictores/síntesis química , Administración Oral , Animales , Unión Competitiva , Disponibilidad Biológica , Encéfalo/irrigación sanguínea , Encéfalo/metabolismo , Células CHO , Bovinos , Cricetinae , Oído/irrigación sanguínea , Estimulación Eléctrica , Cobayas , Humanos , Técnicas In Vitro , Indoles/química , Indoles/farmacología , Masculino , Trastornos Migrañosos/tratamiento farmacológico , Modelos Moleculares , Oxazoles/química , Oxazoles/farmacología , Conejos , Ratas , Receptor de Serotonina 5-HT1B , Receptor de Serotonina 5-HT1D , Receptores de Serotonina/metabolismo , Flujo Sanguíneo Regional/efectos de los fármacos , Agonistas de Receptores de Serotonina/química , Agonistas de Receptores de Serotonina/farmacología , Albúmina Sérica Bovina/metabolismo , Relación Estructura-Actividad , Ganglio del Trigémino/fisiología , Vasoconstrictores/química , Vasoconstrictores/farmacología
6.
Br J Pharmacol ; 121(2): 157-64, 1997 May.
Artículo en Inglés | MEDLINE | ID: mdl-9154322

RESUMEN

1. 311C90 (zolmitriptan zomig: (S)-4[[3-[2-(dimethylamino)ethyl]-1H-indol-5-yl]methyl]-2-oxazolidinone) is a novel 5-HT1B/1D receptor agonist with proven efficacy in the acute treatment of migraine. Here, we describe the receptor specificity of the drug and its actions on trigeminal-evoked plasma protein extravasation into the dura mater of the anaesthetized guinea-pig. 2. At the "5-HT1B-like' receptor mediating vascular contraction (rabbit saphenous vein), the compound was a potent (p[A50] = 6.79 +/- 0.06) partial agonist achieving 77 +/- 4% of the maximum effect to 5-hydroxytryptamine (5-HT). In the same experiments, sumatriptan (p[A50] = 6.48 +/- 0.04) was half as potent as 311C90 and produced 97 +/- 2% of the 5-HT maximum effect. Studies in which receptor inactivation methods were used to estimate the affinity (pKA) and efficacy relative to 5-HT (tau rel) for each agonist confirmed that 311C90 exhibits higher affinity than sumatriptan (pKA = 6.63 +/- 0.04 and 6.16 +/- 0.03, respectively) and that both drugs are partial agonists relative to 5-HT (tau rel = 0.61 +/- 0.03 and 0.63 +/- 0.10, respectively, compared to 5-HT = 1.0). 3. Consistent with its effects in rabbit saphenous vein, 311C90 also produced concentration-dependent contractions of primate basilar artery and human epicardial coronary artery rings. In basilar artery, agonist potency (p[A50] = 6.92 +/- 0.07) was similar to that demonstrated in rabbit saphenous vein, again being 2-3 fold higher than for sumatriptan (p[A50] = 6.46 +/- 0.03). Both agonists produced about 50% of the maximum response obtained with 5-HT in the same preparations. In rings of human coronary artery, the absolute potency of 311C90 and sumatriptan was higher than in primate basilar artery (p[A50] = 7.3 +/- 0.1 and 6.7 +/- 0.1, respectively), but maximum effects relative to 5-HT were lower (37 +/- 8% and 35 +/- 7%, respectively). In both types of vessel, the inability of 5-HT1B/1D agonists to achieve the same maximum as the endogenous agonist 5-HT is explained by the additional presence of 5-HT2A receptors. 4. 311C90 displayed high affinity at human recombinant 5-HT1D (formerly 5-HT1D alpha) and 5-HT1B (formerly 5-HT1D beta) receptors in transfected CHO-K1 cell membranes (pIC50 values = 9.16 +/- 0.12 and 8.32 +/- 0.09, respectively). In intact cells, the drug produced concentration-dependent inhibition of forskolin-stimulated adenylyl cyclase (p[A50] = 9.9 and 9.5, respectively) achieving the same maximum effect as 5-HT. Excepting human recombinant 5-HT1A and 5-ht1F receptors at which the drug behaved as an agonist with modest affinity (pIC50 = 6.45 +/- 0.11 and 7.22 +/- 0.12, respectively), 311C90 exhibited low, or no detectable affinity (pKi or pKB < or = 5.5) at numerous other monoamine receptors, including other 5-HT receptor subtypes. 5. When administered to anaesthetized guinea-pigs ten minutes before unilateral electrical stimulation of the trigeminal ganglion (1.2 mA, 5 Hz, 5 ms, 5 min), 311C90 (3-30 micrograms kg-1, i.v.) caused a dose-dependent inhibition of [125I]-albumin extravasation within the ipsilateral dura mater. At the same doses, the drug also produced dose-dependent falls in cranial vascular conductance (32.3 +/- 7.5% at 30 micrograms kg-1), as measured in the ear by laser doppler flowmetry. 6. These results show that 311C90, a novel member of the 5-HT1B/1D agonist drug class, exhibits a high degree of pharmacological specificity. Its potent partial agonist action at "5-HT1B-like' receptors in intracranial arteries, coupled with potent agonism at 5-HT1D and 5-HT1B receptors and an ability to inhibit neurogenic plasma protein extravasation in the dura, are consistent with its utility as an effective acute treatment for migraine.


Asunto(s)
Vasos Coronarios/efectos de los fármacos , Corazón/efectos de los fármacos , Contracción Muscular/efectos de los fármacos , Oxazoles/farmacología , Oxazolidinonas , Agonistas de Receptores de Serotonina/farmacología , Ganglio del Trigémino/efectos de los fármacos , Animales , Relación Dosis-Respuesta a Droga , Cobayas , Humanos , Masculino , Conejos , Triptaminas
7.
Cardioscience ; 3(3): 145-53, 1992 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-1384747

RESUMEN

Nerve fibers, immunohistochemically positive for neuropeptide Y, tyrosine hydroxylase, calcitonin gene-related peptide and substance P, form a perivascular network surrounding the carotid arteries of New Zealand White rabbits. Transmission electron microscopy demonstrates that the nerve fibers are primarily located at the adventitial-medial border. Placing a silastic collar around a carotid artery for 14 days, in rabbits fed a diet high in cholesterol, resulted in a focal, intimal thickening in 10 out of 12 rabbits. Contralateral sham-operated arteries showed no intimal thickening. At sites where intimal thickening occurred, there was a disappearance of the perivascular nerve network. The carotid arteries from rabbits that did not respond to the collar and the sham-operated carotid arteries showed an intact and normal perivascular nerve network. In the group of animals which responded to the collar with intimal thickening, there was evidence of a proliferative response proximal to the collar and in this same tissue there was evidence of degeneration of nerve fibers. In conclusion, it has been demonstrated for the first time that, in regions of the carotid artery where intimal thickening occurred, there was an associated degeneration of the perivascular nerve network. The cause of this degeneration and its functional consequences require further investigation.


Asunto(s)
Arterias Carótidas/inervación , Enfermedades de las Arterias Carótidas/patología , Arteriosclerosis Intracraneal/patología , Músculo Liso Vascular/inervación , Red Nerviosa/ultraestructura , Animales , Péptido Relacionado con Gen de Calcitonina/análisis , Arterias Carótidas/ultraestructura , Enfermedades de las Arterias Carótidas/etiología , Técnicas para Inmunoenzimas , Arteriosclerosis Intracraneal/etiología , Masculino , Microscopía Electrónica , Fibras Nerviosas/química , Neuropéptido Y/análisis , Conejos , Sustancia P/análisis , Tirosina 3-Monooxigenasa/análisis
8.
Platelets ; 3(3): 129-36, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-21043905

RESUMEN

SC-44368 (5-[6-(1-cyclohexyl-1H-tetrazol-5-y)hexyl]-1,8-naphthyridin-2(1H)-one) is a potent and selective competitive inhibitor of platelet cyclic AMP-dependent phosphodiesterase (cAMP-PDE) (Ki: 1.65 µM). For the phosphodiesterase isoenzyms from human platelets SC-44368 shows a 26-fold selectivity (IC50 ratio) for the inhibition of the cAMP-PDE over the cyclic GMP-dependent phosphodiesterase (cGMP-PDE). By comparison, 3-isobutyl-1-methyl-xanthine (IBMX) inhibited the cAMP-PDE and cGMP-PDE from human platelets with approximately equal efficacy. Broad inhibitory activity was evident against human platelet aggregatory responses in vitro. IC50 values of 18.1 ± 5.3 µM (25 nM platelet activating factor, PAF), 17.3 ± 3.0 µM (1.0 µg/ml collagen) and 24.2 ± 10.3 µM (1µM ADP) were obtained against maximum increases in platelet-rich plasma (PRP) light transmission achieved by each agonist. SC-44368 potentiated the prostacyclin-induced increase of intra-platelet cAMP levels but did not potentiate the sodium nitroprusside-induced increase of intraplatelet cGMP levels. In an ex vivo model of platelet aggregation SC-44368 (3 mg/kg, i.v.) produced a potent inhibition of collagen-induced platelet aggregation. SC-44368 produced only weak hypotensive activity in the rat. Thus, SC-44368 is a novel cAMP-PDE inhibitor which possesses potent, broad spectrum anti-aggregatory properties.

9.
Magn Reson Imaging ; 9(3): 365-71, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-1881255

RESUMEN

Transverse cardiac-cycle gated high resolution magnetic resonance images have been obtained from the neck of the New Zealand white rabbit both in normal animals and from those in which a collar had been earlier positioned around one carotid artery. The study included animals fed on normal and on high cholesterol diets with the surgical modification having been demonstrated previously to cause a rapid and reproducible lesion resembling early atherosclerosis. The aim of the work was to investigate the attainable spatial resolution and sensitivity at a field strength of 2 T using a large radiofrequency transmitter system and a surface coil receiver with which spin-echo images have been obtained. Visualization was enhanced using a three-dimensional interpolation technique. An image resolution of 200 microns was readily obtained but was shown to be insufficient for delineating pathological features within the artery wall such as intimal layer thickening. The results have been compared with histopathological findings which confirmed that any morphological changes were within the pixel resolution of the image. Extensions to the methodology are proposed which should be able to detect atherosclerotic changes with a resolution of 50 microns within a feasible imaging time. In addition, the MRI study of how the surgical intervention alters the artery shape and curvature was carried out and the MRI demonstrated that collar implantation in general does not occlude the artery and causes only a slight and gradual degree of curvature to the vessel.


Asunto(s)
Arteriosclerosis/diagnóstico , Enfermedades de las Arterias Carótidas/patología , Imagen por Resonancia Magnética , Animales , Arteriosclerosis/etiología , Arterias Carótidas/patología , Enfermedades de las Arterias Carótidas/etiología , Dieta Aterogénica , Masculino , Prótesis e Implantes , Conejos
11.
NMR Biomed ; 3(2): 95-100, 1990 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-2390459

RESUMEN

High resolution 1H and 13C NMR spectroscopic measurements including 1H/13C 2D correlation and magnetic resonance imaging (MRI) studies, have been carried out on intact rabbit aortic tissues ex vivo using animals fed both normal and high cholesterol diets. The results show that 1H and 13C NMR spectroscopy can distinguish mobile lipids and can differentiate between normal triglyceride content and cholesterol-enriched lipids, in intact tissue, There were considerable differences in the level of deposition of cholesteryl esters in animals all fed on the same diet. Confirmation is presented of temperature-dependent differences in mobility and organization between the triglycerides found in control tissue and the cholesteryl esters found in aortas from high lipid diet animals. Water-suppressed MRI showed evidence of lipid accumulation in the aortas of high cholesterol diet rabbits. It is concluded that the hypercholesterolaemic rabbit model of atherosclerosis, coupled with such NMR methods, may offer a noninvasive method of monitoring disease development, allowing the evaluation of the effect of therapeutic agents on the progress of atherosclerosis.


Asunto(s)
Arteriosclerosis/diagnóstico , Metabolismo de los Lípidos , Imagen por Resonancia Magnética , Espectroscopía de Resonancia Magnética , Animales , Aorta/metabolismo , Arteriosclerosis/metabolismo , Dieta Aterogénica , Masculino , Conejos
12.
Atherosclerosis ; 76(2-3): 257-68, 1989 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-2659008

RESUMEN

A new rabbit model of atherosclerosis is described in which several of the features seen in early human atherosclerosis are generated within a period of 7 days. The positioning of a hollow silastic collar around the carotid artery of a cholesterol-fed rabbit results in macrophage and smooth muscle cell infiltration into the arterial subendothelium, foam cell formation and the deposition of extracellular lipid. A time-dependent accumulation of extracellular cholesteryl ester occurs within the arterial wall. Each of these changes occurs in the presence of a morphologically intact endothelium as assessed using light microscopy, scanning and transmission electron microscopy. A high cholesterol diet did not affect the extent of proliferation but exacerbated cholesteryl ester accumulation. It is proposed that the changes induced by the collar may be mediated by obstruction of the adventitial vasa vasorum with the creation of a localised ischaemic region.


Asunto(s)
Arteriosclerosis/etiología , Arterias Carótidas/fisiopatología , Enfermedades de las Arterias Carótidas/etiología , Vasa Vasorum/fisiopatología , Animales , Dieta Aterogénica , Epoprostenol/biosíntesis , Conejos
13.
Br J Pharmacol ; 96(2): 395-405, 1989 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-2522336

RESUMEN

1. The inhibitory effect of a selective prostaglandin H2 (PGH2)/thromboxane A2 receptor antagonist, EP 092, on platelet aggregatory responses in whole blood ex vivo (guinea-pig: Rhesus monkey) and intravascular aggregation in vivo (rabbit) has been investigated. 2. Collagen (0.1-10.0 micrograms ml-1) caused a concentration-dependent decrease in single platelet count in samples of both guinea-pig and Rhesus monkey citrated whole blood incubated ex vivo. EP 092 administered to guinea-pigs by intravenous (0.1-3.0 mg kg-1) or oral (1.0-10.0 mg kg-1) routes significantly inhibited the platelet responses to collagen (ED50 values 1.3 +/- 0.2 and 1.4 +/- 0.2 mg kg-1 respectively). Similar potency against collagen-induced whole blood aggregation was observed in Rhesus monkey blood samples following EP 092 given orally (ED50 0.9 +/- 0.3 mg kg-1). 3. The duration of action of EP 092 against collagen aggregatory responses ex vivo in both guinea-pigs and Rhesus monkeys was between 3 and 6 h following oral administration at 3.0 mg kg-1. 4. The inhibitory activity demonstrated by EP 092 against collagen-induced aggregation of Rhesus monkey whole blood ex vivo was not accompanied by any significant reduction in thromboxane A2 formation except at the highest dose tested (10 mg kg-1). 5. The intravascular aggregatory response induced by collagen or thrombin in the anaesthetized rabbit was significantly inhibited by an intravenous infusion of EP 092 (10 mg kg-1). EP 092 appeared less potent and its effect was of shorter duration in this preparation compared with its inhibitory effect on ex vivo aggregation, being evident immediately after infusion of drug but not after a further 30 min. 6. It is concluded that collagen-induced platelet aggregatory response in guinea-pig and Rhesus monkey whole blood ex vivo and rabbit in vivo exhibit a thromboxane-dependent component which can be inhibited in a dose-related fashion by pretreatment with the thromboxane antagonist EP 092. In the rabbit, moreover, the data support the possibility of a role for thromboxane in the intravascular aggregatory response to thrombin.


Asunto(s)
Agregación Plaquetaria/efectos de los fármacos , Prostaglandinas Sintéticas/farmacología , Receptores de Prostaglandina/efectos de los fármacos , Administración Oral , Animales , Colágeno/antagonistas & inhibidores , Cobayas , Inyecciones Intravenosas , Macaca mulatta , Masculino , Prostaglandinas Sintéticas/administración & dosificación , Conejos , Receptores de Tromboxanos , Especificidad de la Especie , Tromboxano A2/biosíntesis , Tromboxano B2/biosíntesis
14.
Thromb Haemost ; 59(2): 164-70, 1988 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-3133807

RESUMEN

SC 38249 [RS)-1-(2,3-bis-[(4-methoxyphenyl)methoxy]propyl)-1H-imidazole) caused dose-related inhibition of collagen-induced thromboxane A2 formation in human platelet rich plasma (IC50: 9.9 +/- 1.0 microM) accompanied by a dose-dependent increase in plasma PGE2. Broad inhibitory activity was evident against human platelet aggregatory and secretory responses in vitro. IC50 values of 11.9 +/- 1.9 microM (0.64 mM arachidonic acid), 18.3 +/- 3.8 microM (0.5 microgram ml-1 collagen) and 37.6 +/- 6.1 microM (25 nM Paf-acether) were obtained against maximum increase in PRP light transmission achieved by each agonist. Although less potent, SC 38249 retained significant inhibitory activity against PRP responses induced by a higher (3.0 micrograms ml-1) concentration of collagen (IC50: 272.5 +/- 24.6 microM), and against Paf-acether-induced responses in PRP pre-treated with 10 microM indomethacin (I.C.50: 192.0 +/- 16.1 microM). Experimental animal studies confirmed the in vitro anti-aggregatory efficacy of SC 38249, since significant inhibitory activity was observed against Paf-acether and ADP-induced responses in dog PRP ex vivo, anti-Forssman antibody-induced thrombocytopenia in anaesthetized guinea pigs, and collagen-induced intravascular aggregation in anaesthetized rabbits. Thus, SC 38249 is a novel thromboxane synthase inhibitor which possesses interesting anti-aggregatory properties which cannot wholly be attributed to prevention of platelet thromboxane A2 formation.


Asunto(s)
Imidazoles/farmacología , Agregación Plaquetaria/efectos de los fármacos , Adolescente , Adulto , Animales , Ácido Araquidónico , Ácidos Araquidónicos/farmacología , Colágeno/farmacología , Dinoprostona , Perros , Humanos , Técnicas In Vitro , Masculino , Prostaglandinas E/sangre , Conejos , Trombocitopenia/prevención & control , Tromboxano A2/sangre , Tromboxano-A Sintasa/antagonistas & inhibidores
15.
Arzneimittelforschung ; 37(6): 669-74, 1987 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-2822055

RESUMEN

Human platelet adenosine-3',5'-cyclic monophosphate (cAMP) levels were determined in platelet rich plasma (PRP) and in washed platelets by a modification of the protein binding assay; the validation of the method is described. Dihydroergotamine (DHE) inhibited epinephrine induced platelet aggregation (ID50 = 2.5 X 10(-7) mol/l), and increased cAMP levels in platelets by an alpha-adrenergic receptor blocking effect, since phentolamine but not propranolol, behaved similarly. The DHE induced cAMP accumulation was correlated to the inhibitory effect on aggregation and showed a characteristic alpha-adrenergic receptor pattern in the presence of alprostadil (PGE1) and epinephrine but not collagen or adenosine diphosphate (ADP). Thrombin induced aggregation was similarly affected by DHE but with 100 times higher concentration. Heparin was found to increase slightly ADP and epinephrine induced aggregation and to decrease cAMP. Also, heparin was found to inhibit thrombin induced platelet aggregation. In washed platelets, the inhibitory effect of thrombin on PGE1 induced cAMP accumulation was counteracted by heparin. This indicates that the binding site of thrombin on platelets is important in the control of adenyl cyclase. Evidence is presented that some of the beneficial synergistic effect of DHE and heparin may consist in the ability of those compounds to produce opposite effects on cAMP system in platelets.


Asunto(s)
Plaquetas/metabolismo , AMP Cíclico/sangre , Dihidroergotamina/farmacología , Heparina/farmacología , Alprostadil/farmacología , Epinefrina/farmacología , Humanos , Técnicas In Vitro , Agregación Plaquetaria/efectos de los fármacos , Teofilina/farmacología , Trombina/farmacología
16.
Thromb Haemost ; 56(1): 80-5, 1986 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-3775692

RESUMEN

Collagen (10-40 micrograms kg-1), thrombin (1-10 units kg-1), adenosine diphosphate (ADP; 3-300 micrograms kg-1), 1-0-hexadecyl Paf-acether and 1-0-octadecyl Paf-acether (1-300 ng kg-1) administered by bolus intravenous injection each caused dose-dependent thrombocytopoenia accompanied by marked hypotension in anaesthetized rabbits. Responses to ADP and the Paf-acether derivatives were transient in nature (3-8 min) whereas those induced by collagen and thrombin were always of longer duration (5-20 min) and frequently fatal at high doses. Responses to collagen, thrombin, and the Paf-acether derivatives were invariably accompanied by substantial, dose-related increases in plasma levels of thromboxane B2 in samples obtained 30 s after agonist administration, whereas following ADP, no change in plasma thromboxane B2 was detected at any dose level. Indomethacin (3.0 mg kg-1 by infusion) had no effect on responses to thrombin or Paf-acether, partially inhibited collagen-induced thrombocytopenia, and potentiated responses to ADP. In contrast, dazoxiben (10 mg kg-1 by infusion) partially but significantly inhibited responses to thrombin, whereas those induced by collagen, Paf-acether or ADP were unchanged. These results indicate that in this model of intravascular aggregation, whilst platelet responses to collagen and thrombin appear partially dependent on intact cyclic endoperoxide and thromboxane A2 synthetic capacity respectively, responses to ADP and Paf-acether are independent of arachidonate metabolism via cyclo-oxygenase despite measurably increased TXB2 formation in the latter case.


Asunto(s)
Imidazoles/farmacología , Indometacina/farmacología , Agregación Plaquetaria/efectos de los fármacos , Adenosina Difosfato/farmacología , Animales , Colágeno/farmacología , Relación Dosis-Respuesta a Droga , Masculino , Factor de Activación Plaquetaria/análogos & derivados , Factor de Activación Plaquetaria/farmacología , Conejos , Trombina/fisiología , Tromboxano B2/sangre
17.
Lancet ; 2(8196): 663-7, 1980 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-6106784

RESUMEN

Plasma beta-thromboglobulin (beta-TG), a marker of in-vivo platelet release reaction, was measured in 27 meniscectomy patients, 10 patients who underwent total knee replacements (TKR) (both procedures performed under tourniquet ischaemia), and 10 herniorrhaphy patients. In 22 meniscectomy and 7 TKR patients plasma-thromboxane-B2 (TxB2), a stable end-product of thromboxane-synthetase activity, was also determined. The mean plasma beta-TG and TxB2 had risen significantly within 5 min of release of the tourniquet, indicating increased in-vivo platelet release reaction and prostaglandin synthesis in these patients. In the herniorrhaphy patients beta-TG and TxB2 did not alter significantly postoperatively. In 6 pigs (weighing 20-30 kg) who underwent meniscectomy under tourniquet ischaemia plasma TxB2 rose significantly 15-30 min after release of the tourniquet, and prostacyclin release was significantly lower from veins exposed to ischaemia than from control veins. Large de-endothelialised areas were seen on scanning electron-micrographic sections of affected veins, and these areas were covered with a monolayer of platelets and platelet clumps. These changes associated with tourniquet ischaemia may explain the high incidence of venous thrombosis seen in patients undergoing meniscectomy and TKR.


Asunto(s)
Plaquetas/metabolismo , Epoprostenol/metabolismo , Isquemia/metabolismo , Prostaglandinas/metabolismo , Tromboxano B2/biosíntesis , Tromboxanos/biosíntesis , Adulto , Animales , Femenino , Humanos , Isquemia/etiología , Rodilla/irrigación sanguínea , Rodilla/cirugía , Masculino , Meniscos Tibiales/irrigación sanguínea , Persona de Mediana Edad , Porcinos , Torniquetes , beta-Tromboglobulina/metabolismo
18.
Br J Pharmacol ; 67(1): 123-31, 1979 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-227506

RESUMEN

1 An isolated stomach preparation from immature rats has been used to study the role of extracellular calcium in the control of gastric acid secretion. Calcium was removed from both the serosal and mucosal solutions either in the absence of a chelating agent or in the presence of EGTA.2 Removal of calcium in the absence of EGTA had no significant effect on basal acid secretion or the acid responses to gastrin and dibutyryl cyclic adenosine 3',5'-monophosphate (db cyclic AMP). Under the same conditions there was a marked potentiation of the acid response to histamine, and a reduction of the acid response to acetylcholine which was readily reversed on restoring calcium to the bathing solutions.3 Removal of calcium in the presence of EGTA caused an inhibition of basal acid secretion and of the acid responses to histamine and db cyclic AMP. In each case this reduction in acid output was readily reversed on bathing the stomachs in normal calcium-containing (2.5 mM Ca(2+)) EGTA-free solutions.4 The inhibition of the acid response to histamine produced by Ca(2+)-free solutions which contained EGTA was not reversed on bathing the stomachs in solutions that contained both EGTA (0.1 mM) and an excess of calcium (2.5 mM).5 The removal of extracellular calcium in the absence of EGTA provided evidence that the secretion of H(+) ions is dependent under some conditions on calcium ions. The possibility cannot be excluded that EGTA itself exerts an inhibitory influence on the process of acid secretion.


Asunto(s)
Calcio/fisiología , Jugo Gástrico/metabolismo , Mucosa Gástrica/metabolismo , Acetilcolina/farmacología , Animales , Bucladesina/farmacología , Ácido Egtácico/farmacología , Gastrinas/farmacología , Histamina/farmacología , Técnicas In Vitro , Ratas
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