RESUMO
BACKGROUND AND AIMS: The Wound-QoL is a validated and feasible questionnaire for measuring disease-specific health-related quality of life in chronic wounds, originally developed for use in German. The objective of this study was to translate the Wound-QoL for use in clinical care and in clinical trials in Spain and to validate this version. MATERIALS AND METHODS: Two independent fourth- and back translations of the Wound-QoL from the original German version were conducted, followed by an expert consensus of the resulting versions. After refinement, the final tool was piloted in N=10 patients and then used in the validation study. RESULTS: A total of 115 patients were recruited. Mean age was 69.5 (SD 14.5) years, 60.0% were female. The Spanish version of Wound-QoL showed high internal consistency (Cronbach's alpha>0.8 in all scales). Factor analysis resulted in the same scales as the original version. There were satisfactory distribution characteristics of the global score and the subscales. Construct validity and convergent validity with other outcomes (generic QoL, healing rate) were satisfactory. The vast majority of patients considered the Wound-QoL a simple and feasible tool. Mean time needed for completing the questionnaire was 5minutes. Overall, 99.1% of the participants found it easy to understand the questions and 94.7% stated that the questionnaire suits the personal situation. CONCLUSIONS: The Spanish version of the Wound-QoL shows good validity in clinical practice. It can be recommended for use in clinical routine and trials.
Assuntos
Qualidade de Vida , Traduções , Idoso , Análise Fatorial , Feminino , Humanos , Espanha , Inquéritos e QuestionáriosRESUMO
Quality management systems (QMS) are tools that serve to structure, control and improve the usual activities that take place in an organization or service. The ISO 9001:2015 is an internationally recognized standard, which provides the necessary resources to help an organization to improve its performance, based on the principle of plan-do-control-act, in order to obtain continuous improvement. In the field of health, it is an essential tool for the management of the services offered to patients. The ISO quality certification allows to demonstrate compliance, according to established quality standards. The process of implementing a QMS follows several phases that culminate with the completion of an external audit, which once passed, allows obtaining the quality certification ISO 9001:2015. This article describes the steps to follow to obtain this certification in a Dermatology Service.
Assuntos
Dermatologia/normas , Departamentos Hospitalares/normas , Gestão da Qualidade Total/normas , Melhoria de Qualidade , EspanhaRESUMO
A large proportion of lower-risk myelodysplastic syndromes (MDS) respond to erythropoiesis-stimulating agents (ESA), but most responses are transient. We updated a previously reported cohort of lower-risk MDS patients treated with ESA and analyzed outcomes after ESA failure. In 120 patients with primary resistance and 66 patients with relapse after an initial response to ESA, the 5-year cumulative incidence of acute myeloid leukemia (AML) after failure was 18.9% and 11.6%, respectively (P=0.20). Median overall survival (OS) after failure was 40.1 and 44.9 months (P=0.35), respectively. We further categorized patients as 'early failures' (including resistance and relapse after <6 months of response), or 'later failures' (that is, relapse after ≥6 months). The 5-year cumulative incidence of AML and median OS after failure in early and later failure were 21.6% and 9% (P=0.02) and 36.7 and 54.3 months (P=0.02), respectively. Early failure to ESA and a baseline diagnosis of refractory anemia with excess blasts (RAEB)-1 were independent prognostic factors for AML progression and, along with trisomy 8, for shorter OS. Median OS from treatment onset was 40, 90.7 and 65.8 months in early failure, later failure and no relapse, respectively (P=0.001). Lower-risk MDS with early failure to ESA have a relatively unfavorable outcome, and should be offered alternative treatments.
Assuntos
Anemia/complicações , Cromossomos Humanos Par 5 , Hematínicos/uso terapêutico , Síndromes Mielodisplásicas/tratamento farmacológico , Feminino , Humanos , Masculino , Síndromes Mielodisplásicas/complicações , Síndromes Mielodisplásicas/genética , Recidiva , Resultado do TratamentoRESUMO
Darbepoetin (DAR), with or without granulocyte colony-stimulating factor (G-CSF), has proved effective in treating anemia in patients with lower-risk myelodysplastic syndrome (MDS), but its effects on quality of life (QoL) and exercise functioning are less well established. In this phase II study (no. NCT00443339), lower-risk MDS patients with anemia and endogenous erythropoietin (EPO) level <500 IU/L received DAR 500 µg once every 2 weeks for 12 weeks, with G-CSF added at week 12 in non-responders. Physical performance was assessed with the 6-min walking test and, for fit patients, maximal oxygen consumption (VO2max). QoL was evaluated using SF-36 and FACT-An tests. In 99 patients, erythroid response rate according to IWG 2006 criteria was 48 and 56 % at 12 and 24 weeks, respectively. Addition of G-CSF rescued 22 % of non-responders. In 48 % of the responders, interval between darbepoetin injections could be increased for maintenance treatment. Serum EPO level was the only independent predictive factor of response at 12 weeks, and its most discriminant cutoff value was 100 IU/L. QoL and VO2max showed improvement over time in responders, compared with non-responders. With a median follow-up of 52 months, median response duration was not reached, and 3-year cumulative incidence of acute myeloid leukemia and overall survival (OS) was 14.5 and 70 %, respectively. Baseline transfusion dependence, International Prognostic Score System (IPSS), and Revised IPSS accurately predicted OS from treatment onset. Tolerance of darbepoetin was good. In conclusion, this regimen of darbepoetin every 2 weeks yielded high response rates and prolonged response duration. Objective improvement in exercise testing and in patient-reported QoL confirms the clinical relevance of anemia correction with erythropoiesis-stimulating agents.
Assuntos
Eritropoetina/análogos & derivados , Tolerância ao Exercício/efeitos dos fármacos , Fator Estimulador de Colônias de Granulócitos/administração & dosagem , Síndromes Mielodisplásicas/tratamento farmacológico , Qualidade de Vida , Idoso , Anemia/complicações , Anemia/tratamento farmacológico , Anemia/mortalidade , Anemia/fisiopatologia , Darbepoetina alfa , Eritropoetina/administração & dosagem , Eritropoetina/efeitos adversos , Exercício Físico/fisiologia , Feminino , Filgrastim , Fator Estimulador de Colônias de Granulócitos/efeitos adversos , Hematínicos/administração & dosagem , Hematínicos/efeitos adversos , Humanos , Masculino , Síndromes Mielodisplásicas/complicações , Síndromes Mielodisplásicas/mortalidade , Síndromes Mielodisplásicas/fisiopatologia , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/efeitos adversos , Risco , Análise de Sobrevida , Resultado do TratamentoRESUMO
We evaluated the prognostic value of serum ferritin (SF) level at diagnosis in 318 newly diagnosed IPSS low and int 1 (lower) risk MDS patients included in the French MDS registry, who did not require RBC transfusions and had baseline SF level determination. Increased baseline SF level (>300 ng/ml) was correlated with male gender, more pronounced anaemia, and diagnosis of RARS but had no negative impact on progression to AML or survival.
Assuntos
Transfusão de Sangue , Ferritinas/metabolismo , Síndromes Mielodisplásicas/diagnóstico , Síndromes Mielodisplásicas/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/sangue , Prognóstico , Fatores de Risco , Taxa de SobrevidaRESUMO
BACKGROUND: Neurogenic Para-Osteo-Arthropathy (NPOA) occurs as a consequence of central nervous system injuries or some systemic conditions. They are characterized by bone formation around the main joints. METHODS: In order to define some biological features of NPOAs, histological and immunohistological studies of the soft tissue surrounding osteoma and Ultrasound examination (US) of NPOA before the appearance of abnormal ossification on plain radiographs were performed. RESULTS: We have observed a great number of ossifying areas scattered in soft tissues. US examination have also shown scattered ossifying areas at the early stage of ossification. A high osteogenic activity was detected in these tissues and all the stages of the endochondral process were observed. Mesenchymal cells undergo chondrocytic differentiation to further terminal maturation with hypertrophy, which sustains mineralization followed by endochondral ossification process. CONCLUSION: We suggest that periosteoma soft tissue reflect early stage of osteoma formation and could be a model to study the mechanism of osteoma formation and we propose a mechanism of the NPOA formation in which sympathetic dystony and altered mechanical loading induce changes which could be responsible for the cascade of cellular events leading to cartilage and bone formation.
Assuntos
Artropatia Neurogênica/patologia , Neoplasias Ósseas/patologia , Ossificação Heterotópica/patologia , Osteoma/patologia , Fosfatase Alcalina/metabolismo , Artropatia Neurogênica/complicações , Artropatia Neurogênica/diagnóstico , Artropatia Neurogênica/fisiopatologia , Neoplasias Ósseas/diagnóstico , Neoplasias Ósseas/etiologia , Neoplasias Ósseas/fisiopatologia , Diferenciação Celular , Condrócitos/enzimologia , Condrócitos/patologia , Condrogênese , Colágeno/análise , Cotovelo/diagnóstico por imagem , Quadril/diagnóstico por imagem , Humanos , Imuno-Histoquímica , Joelho/diagnóstico por imagem , Mesoderma/metabolismo , Mesoderma/patologia , Ossificação Heterotópica/complicações , Ossificação Heterotópica/diagnóstico , Ossificação Heterotópica/fisiopatologia , Osteogênese , Osteoma/diagnóstico , Osteoma/etiologia , Osteoma/fisiopatologia , Periósteo/patologia , Estresse Mecânico , Traumatismos do Sistema Nervoso/complicações , Ultrassonografia , Suporte de CargaRESUMO
We investigated the antiischemic properties of a new compound, S-15176, in an experimental model of rat liver subjected to 120-min normothermic ischemia followed by 30-min reperfusion. Rats were divided into groups, pretreated with different doses of S-15176 (1.25, 2.5, 5 and 10 mg/kg/day by intramuscular injection) or solvent alone, and subjected to the ischemia--reperfusion process. Another group served as the sham-operated controls. Ischemia--reperfusion induced huge alterations of hepatocyte functions, namely, a decrease in ATP content and bile flow, and membrane leakage of alanine aminotransferase (ALAT) and aspartate aminotransferase (ASAT). These effects were associated with alterations in mitochondrial functions characterized by (1) a decrease in ATP synthesis, (2) a decrease in NAD(P)H levels and mitochondrial membrane potential, and (3) an increase in mitochondrial swelling reflecting the generation of permeability transition. Pretreatment of rats with S-15176 alleviated these deleterious ischemia--reperfusion effects at both the cellular and mitochondrial levels in a dose-dependent manner. The protection of mitochondrial functions was almost complete at a dosage of 10 mg/kg/day. In addition, in vitro, S-15176 totally abolished the swelling of isolated mitochondria induced by a calcium overload with an IC(50) value of 10 microM. These data demonstrate that S-15176 protects mitochondria against the deleterious effects of ischemia-reperfusion and suggest that this protective effect could be related to the inhibition of the mitochondrial permeability transition.
Assuntos
Hepatócitos/efeitos dos fármacos , Mitocôndrias Hepáticas/efeitos dos fármacos , Piperazinas/farmacologia , Substâncias Protetoras/farmacologia , Trifosfato de Adenosina/metabolismo , Animais , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Ductos Biliares/efeitos dos fármacos , Ductos Biliares/fisiologia , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Relação Dose-Resposta a Droga , Hepatócitos/metabolismo , Isquemia/patologia , Isquemia/prevenção & controle , Hepatopatias/patologia , Hepatopatias/prevenção & controle , Testes de Função Hepática , Masculino , Potenciais da Membrana/efeitos dos fármacos , Mitocôndrias Hepáticas/fisiologia , Dilatação Mitocondrial/efeitos dos fármacos , NADP/metabolismo , Piperazinas/uso terapêutico , Substâncias Protetoras/uso terapêutico , Ratos , Ratos Wistar , Traumatismo por Reperfusão/patologia , Traumatismo por Reperfusão/prevenção & controleRESUMO
The protective effect of N-[(3, 5-di-tertiobutyl-4-hydroxy-1-thiophenyl)]-3-propyl-N'-(2,3, 4-trimethoxybenzyl)piperazine (S-15176) on liver injury induced by warm ischemia-reperfusion was investigated using a rat model. Animals were subjected to 2 h of ischemia followed by different reperfusion times. Hepatocyte integrity was assessed by measuring plasma alanine and aspartate aminotransferase activities, and by determining reduced and oxidized glutathione in plasma and bile. Hepatocyte function was quantitated by determining bile flow and liver ATP content. Ischemia-reperfusion resulted in severe hepatic injury involving a huge increase in alanine and aspartate aminotransferase activities, a drop in ATP content, and a decrease in bile flow. Plasma and bile reduced (GSH) and oxidized (GSSG) glutathione concentrations were inversely related: plasma levels increased when biliary levels decreased. This was associated with a decrease in animal survival (-34%). S-15176 pretreatment (1.25, 2.5, 5 or 10 mg kg(-1) day(-1)) improved the survival rate and limited tissue damages in a dose-dependent manner. The pretreatment also reduced the aminotransferase leakage from hepatocytes and the increase in plasma glutathione levels. In addition, normalization of the plasma GSSG/GSH ratio, a good index of an oxidative stress, was observed in groups treated with the higher dosage, suggesting that the antioxidant properties demonstrated for the compound in vitro (IC(50)=0.3 microM towards lipid peroxidation) could play a role in its protective effect. S-15176 pretreatment also protected the organ from the drop in ATP levels. At the higher dose, ATP content was maintained at a level almost 86% of the sham-operated group after 60 min of reperfusion. This was associated with a restoration of the biliary flow. These data suggest that S-15176 may be a useful drug in liver surgery to prevent ischemia-reperfusion injury.
Assuntos
Antioxidantes/farmacologia , Isquemia/tratamento farmacológico , Fígado/irrigação sanguínea , Piperazinas/farmacologia , Traumatismo por Reperfusão/prevenção & controle , Trifosfato de Adenosina/metabolismo , Animais , Bile/efeitos dos fármacos , Relação Dose-Resposta a Droga , Glutationa/metabolismo , Dissulfeto de Glutationa/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , RatosRESUMO
Trimetazidine, an antiischaemic drug, has been shown to restore impaired mitochondrial functions. Specific binding sites for [(3)H]-trimetazidine have been previously detected in liver mitochondria. In the present study we confirm this observation and provide additional evidence for the involvement of these sites in the pharmacological effects of the drug. Inhibition experiments using a series of trimetazidine derivatives revealed the presence of three classes of binding sites. An N-benzyl substituted analogue of trimetazidine exhibited a very high affinity (K(i)=7 nM) for one of these classes of sites. Compounds from different pharmacological classes were evaluated for their ability to inhibit [(3)H]-trimetazidine binding. Among the drugs tested pentazocine, ifenprodil, opipramol, perphenazine, haloperidol, and to a lower extent prenylamine, carbetapentane and dextromethorphan competed with high affinity, suggesting a similarity of high affinity [(3)H]-trimetazidine sites with sigma receptors. [(3)H]-Trimetazidine binding was modulated by pH. Neutral trimetazidine had about 10 fold higher affinity than protonated trimetazidine for its mitochondrial binding sites. Various cations also affected [(3)H]-trimetazidine binding. Ca(2+) was the most potent inhibitor and totally suppressed the binding of [(3)H]-trimetazidine to the sites of medium affinity. An endogenous cytosolic ligand was able to displace [(3)H]-trimetazidine from its binding sites. Its activity was not affected by boiling for 15 min, suggesting a non-protein compound. These data suggest that mitochondrial [(3)H]-trimetazidine binding sites could have a physiological relevance and be involved in the antiischaemic effects of the drug.
Assuntos
Mitocôndrias/metabolismo , Receptores de Superfície Celular/efeitos dos fármacos , Trimetazidina/análogos & derivados , Trimetazidina/metabolismo , Vasodilatadores/metabolismo , Algoritmos , Animais , Sítios de Ligação/efeitos dos fármacos , Química Encefálica/efeitos dos fármacos , Cátions/farmacologia , Citosol/metabolismo , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Masculino , Mitocôndrias/efeitos dos fármacos , Mitocôndrias Hepáticas/efeitos dos fármacos , Mitocôndrias Hepáticas/metabolismo , Ratos , Ratos WistarRESUMO
The aim of this study was to investigate beta(1)- and beta(2)-adrenoceptor signalling systems in the rat brain studying the synergistic effects between beta-adrenoceptor agonists and forskolin- induced activation of adenylyl cyclase. Experiments were performed in slices from cerebral cortex and cerebellum because they contain mainly beta(1)- and almost exclusively beta(2)- adrenoceptors, respectively. Five beta-adrenergic agonists were used, clenbuterol, flerobuterol, isoproterenol, salbutamol, and tulobuterol. All agonists stimulated cyclic AMP accumulation in the cerebral cortex but flerobuterol was inactive in the cerebellum. Forskolin amplified the generation of cyclic AMP. Forskolin potentiation was observed in glial cells but not in neurons and was not dependent on the number of beta-adrenoceptors. In return the amplitude of the potentiation was highly dependent on the intrinsic activity of the agonist in the cerebral cortex whereas it was constant whatever the agonist tested in the cerebellum. To analyse this difference we developed a modelling approach using a concentration-response study. Isoproterenol and forskolin stimulations of cyclic AMP production were studied either alone or in combination with increasing concentrations of forskolin and isoproterenol, respectively. In the cerebral cortex isoproterenol and forskolin were both able to potentiate the cyclic AMP accumulation induced by the other compound, whereas, in the cerebellum, isoproterenol was unable to increase the stimulation induced by forskolin. The results support the hypothesis that beta(1)- and beta(2)-adrenoceptors display distinct mechanisms of action in the signalling system by which they stimulate the accumulation of cyclic AMP.
Assuntos
Adenilil Ciclases/metabolismo , Química Encefálica/efeitos dos fármacos , Colforsina/farmacologia , Receptores Adrenérgicos beta 1/efeitos dos fármacos , Receptores Adrenérgicos beta 2/efeitos dos fármacos , Agonistas Adrenérgicos beta/farmacologia , Algoritmos , Animais , Antidepressivos Tricíclicos/farmacologia , Encéfalo/enzimologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/enzimologia , AMP Cíclico/metabolismo , Desipramina/farmacologia , Técnicas In Vitro , Isoproterenol/farmacologia , Masculino , Modelos Teóricos , Sistema Nervoso Periférico/citologia , Sistema Nervoso Periférico/efeitos dos fármacos , Ratos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacosRESUMO
We investigated the effects of cinnarizine and flunarizine on mitochondrial permeability transition, ATP synthesis, membrane potential and NAD(P)H oxidation. Both drugs were effective in inhibiting the mitochondrial permeability transition induced either by Ca2+ alone or in the presence of tert-butylhydroperoxide. This protective effect occurred at low concentrations (< 50 microM) of these drugs and was accompanied by the inhibition of NAD(P)H oxidation and the restoration of the mitochondrial membrane potential decreased by a high concentration of Ca2+ (25 microM). However, at higher concentrations (> 50 microM) of cinnarizine and flunarizine and in the absence of both tert-butylhydroperoxide and Ca2+, their effects on the mitochondria were reversed as follows: mitochondrial permeability transition was generated, mitochondrial NAD(P)H was oxidized and membrane potential collapsed. These deleterious effects were not antagonized by cyclosporine A, the most potent inhibitor of the mitochondrial permeability transition, but by 2,6-di-tert-butyl-4-methylphenol, a known antioxidant agent. This mitochondrial effect was neither accompanied by an increase in malondialdehyde production nor by an increase in H2O2 generation, which attested that the effect of both drugs was not due to an increase in reactive oxygen species production. The dual effects of both cinnarizine and flunarizine on mitochondrial functions is discussed with regard to both the protective effect afforded by these drugs against ischemia-reperfusion injury and their side effect observed in some therapeutic situations where an overdosage seems likely.
Assuntos
Cinarizina/farmacologia , Flunarizina/farmacologia , Antagonistas dos Receptores Histamínicos H1/farmacologia , Mitocôndrias Hepáticas/metabolismo , Animais , Cálcio/metabolismo , Relação Dose-Resposta a Droga , Técnicas In Vitro , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Malondialdeído/metabolismo , Potenciais da Membrana/efeitos dos fármacos , Mitocôndrias Hepáticas/efeitos dos fármacos , Dilatação Mitocondrial/efeitos dos fármacos , NADP/metabolismo , Oxirredução , Estresse Oxidativo/fisiologia , Permeabilidade , Ratos , Ratos WistarRESUMO
Recent studies suggest a crucial role played by mitochondria in the pathogenesis of ischemia-reperfusion injury. This study was conducted to clarify the role of trimetazidine, a cellular anti-ischemic agent, on mitochondria isolated from rat liver subjected to 120-min normothermic ischemia followed by 30-min reperfusion. Rats were divided into groups, pretreated with different doses of trimetazidine (5, 10 and 20 mg/kg/day) or saline and subjected to the ischemia-reperfusion process; another group served as the sham-operated controls. Alanine aminotransferase and aspartate aminotransferase activities and hepatocyte ATP content, bile flow and mitochondrial functions were assessed. Ischemia-reperfusion caused membrane leakage from hepatocytes and a decrease in ATP content and in bile flow. These effects were well correlated with alterations in mitochondrial function, namely, decrease in ATP synthesis, NAD(P)H level and mitochondrial membrane potential and generation of mitochondrial permeability transition. The pretreatment of rats with trimetazidine prevented these ischemia-reperfusion deleterious effects at both the cellular and mitochondrial level in a dose-dependent manner. It is concluded that trimetazidine at an optimal dosage of 10 mg/kg/day protects mitochondria against the deleterious effects of ischemia-reperfusion. This protective effect appears to be the key factor through which this drug exerts its cytoprotective activity.
Assuntos
Isquemia/metabolismo , Fígado/irrigação sanguínea , Mitocôndrias Hepáticas/efeitos dos fármacos , Traumatismo por Reperfusão/metabolismo , Trimetazidina/farmacologia , Vasodilatadores/farmacologia , Trifosfato de Adenosina/biossíntese , Animais , Fígado/efeitos dos fármacos , Masculino , Potenciais da Membrana/efeitos dos fármacos , Mitocôndrias Hepáticas/metabolismo , Dilatação Mitocondrial/efeitos dos fármacos , NAD/metabolismo , Ratos , Ratos Wistar , Espécies Reativas de OxigênioRESUMO
1. Trimetazidine is an anti-ischaemic drug effective in different experimental models but its mechanism of action is not fully understood. Data indicate that mitochondria could be the main target of this drug. The aim of this work was to investigate the binding of [3H]-trimetazidine on a purified preparation of rat liver mitochondria. 2. [3H]-trimetazidine binds to two populations of mitochondrial binding sites with Kd values of 0.96 and 84 microM. The total concentration of binding sites is 113 pmol mg(-1) protein. Trimetazidine binding sites are differently distributed. The high-affinity ones are located on the outer membranes and represent only a small part (4%) of total binding sites, whereas the low-affinity ones are located on the inner membranes and are more abundant (96%) with a Bmax=108 pmol mg(-1) protein. 3. Drug displacement studies with pharmacological markers for different mitochondrial targets showed that [3H]-trimetazidine binding sites are different from previously described mitochondrial sites. 4. The possible involvement of [3H]-trimetazidine binding sites in the regulation of the mitochondrial permeability transition pore (MTP), a voltage-dependent channel sensitive to cyclosporin A, was investigated with mitochondrial swelling experiments. Trimetazidine inhibited the mitochondrial swelling induced by Ca2+ plus tert-butylhydroperoxide (t-BH). This effect was concentration-dependent with an IC50 value of 200 microM. 5. Assuming that trimetazidine effectiveness may be related to its structure as an amphiphilic cation, we compared it with other compounds exhibiting the same chemical characteristic both for their ability to inhibit MTP opening and to displace [3H]-trimetazidine bound to mitochondria. Selected compounds were drugs known to interact with various biological membranes. 6. A strong correlation between swelling inhibition potency and low-affinity [3H]-trimetazidine binding sites was observed: r=0.907 (n=24; P<0.001). 7. These data suggest that mitochondrial sites labelled with [3H]-trimetazidine may be involved in the MTP inhibiton.
Assuntos
Mitocôndrias Hepáticas/metabolismo , Trimetazidina/metabolismo , Vasodilatadores/metabolismo , Animais , Sítios de Ligação , Técnicas In Vitro , Membranas Intracelulares/metabolismo , Masculino , Permeabilidade , Ratos , Ratos Wistar , Frações Subcelulares/metabolismo , TrítioRESUMO
Inhibition experiments of (-)[3H]CGP 12177 binding by (-)isoproterenol and salbutamol were performed on synaptosomes prepared from rat brain cortex and cerebellum. Adenylyl cyclase (AC) stimulation experiments on slices of these structures were also performed, with measuring [14C]cAMP obtained from [14C]adenine. Studying beta 1- and beta 2-adrenoceptors (beta 2AR) separately, dissociation constants of (-)isoproterenol for the high- (KH) and low- (KL) affinity states are 8 and 206 nM, respectively, for beta 1AR, vs 20 and 900 nM for beta 2AR. With salbutamol, KH and KL for beta 2AR are 37 and 1250 nM, respectively, vs 430 and 8500 nM for beta 1AR. In any case, the proportion of high-affinity state (RH) of beta 2AR in the cerebellum (59% and 35% for (-)isoproterenol and salbutamol, respectively) is twice that of beta 1AR (30% and 18%). Surprisingly, the RH of cortex beta 2AR with (-)isoproterenol (30%) is significantly lower than in the cerebellum, but not with salbutamol (35%). To allow meaningful comparisons of potencies in stimulating [14C]cAMP production, we define the coupling efficiency (CE), applicable to specified beta AR subtype and agonist, and expressed as the maximal production of mol cAMP.mol-1 beta AR.min-1. The order of CE was always in favor of (-)isoproterenol vs salbutamol on cerebellum beta 2AR > on cortex beta 2AR > on cortex beta 1AR. This order indicates the partial agonism of salbutamol for both beta AR subtypes, and an intrinsic better coupling of beta 2AR vs beta 1AR in rat brain. Moreover, this order corresponds roughly to that of RH. Hence, CE is directly correlated with RH at least for these two agonists. EC50 for cAMP production for each subtype and agonist is in the same order than the respective KL, and might only reflect the rapid return of receptor to low-affinity state after the activation of Gs protein. In binding experiments on the whole beta AR in both areas, the pseudo-Hill coefficient did not reach 1 with 0.3 mM guanosine 5'-(beta, gamma-imido)triphosphate (GppNHp). This dysfunction of GppNHp in rat brain structures might be caused by a major difference in the regulation of coupling in the ternary complex as compared with peripheral tissues.
Assuntos
Adenilil Ciclases/metabolismo , Agonistas Adrenérgicos beta/farmacologia , Albuterol/farmacologia , Encéfalo/enzimologia , Isoproterenol/farmacologia , Receptores Adrenérgicos beta/metabolismo , Agonistas Adrenérgicos beta/farmacocinética , Albuterol/farmacocinética , Animais , Encéfalo/efeitos dos fármacos , Cerebelo/efeitos dos fármacos , Cerebelo/enzimologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/enzimologia , AMP Cíclico/biossíntese , Guanilil Imidodifosfato/farmacologia , Técnicas In Vitro , Isoproterenol/farmacocinética , Masculino , Propanolaminas/farmacocinética , Ratos , Ratos Wistar , Receptores Adrenérgicos beta/efeitos dos fármacos , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/enzimologiaRESUMO
The binding and characteristics of rat brain beta-adrenergic receptors (beta-AR) isolated from astrocytes and neurons were investigated. Equilibrium binding experiments demonstrated that beta-AR were more concentrated on astrocytes than on neurons isolated from forebrain, cerebral cortex and cerebellum. Inhibition experiments revealed that beta 1-AR and beta 2-AR were present in the two cell types. Isoproterenol revealed two interchangeable states of high and low affinity binding to both beta 1- and beta 2-AR in neurons. The high affinity binding sites were sensitive to guanylylimidodiphosphate (GppNHp). Similar results were found with other beta-AR agonists but not with salbutamol and salmeterol which recognized both affinity states of the neuronal beta 2-AR but only the low affinity state of beta 1-AR. In astrocytes only the low affinity state of beta-AR was observed.
Assuntos
Astrócitos/metabolismo , Neurônios/metabolismo , Receptores Adrenérgicos beta/metabolismo , Agonistas Adrenérgicos beta/metabolismo , Antagonistas Adrenérgicos beta/metabolismo , Animais , Ligação Competitiva , Células Cultivadas , Cerebelo/citologia , Cerebelo/metabolismo , Imidazóis/metabolismo , Imuno-Histoquímica , Masculino , Propanolaminas/metabolismo , Prosencéfalo/citologia , Prosencéfalo/metabolismo , Ratos , Ratos Wistar , Receptores Adrenérgicos beta/análiseRESUMO
Cyclosporine A (CsA) is a known potent inhibitor of pro-oxidant-induced mitochondrial swelling. In the present study we show that CsA's effect is only transient when the liver mitochondrial swelling in induced by Ca2+ plus tert-butylhydroperoxide (t-BH). After an initial inhibition, swelling is worsened by CsA as evidenced by an extent of mitochondrial swelling that exceeds that of the control. Unlike CsA, trimetazidine (TMZ), an anti-ischemic drug decreases both the extent and the rate of the swelling with an IC50 value of 214 +/- 24 microM. Its inhibition effect on the initial swelling rate mimicks that of CsA but the mechanism may be independent. During long-term swelling. TMZ counteracts the worsening effect of CsA. The inhibition of swelling induced by TMZ is assessed by the fact that TMZ significantly increases the EC50 of Ca(2+)-induced mitochondrial swelling (46.6 +/- 6.0 to 85 +/- 10 microM, P < 0.01), without affecting its cooperativity. Apparently, TMZ seems to behave like trifluoperazine (TFP), a phospholipase A2 inhibitor that, under our experimental conditions, inhibits the mitochondrial swelling induced by Ca2+ and t-BH with an IC50 value of 25 +/- 10 microM. Both drugs are able to protect mitochondria from both phases (early and late) of the swelling, especially the late, which is enhanced in the presence of CsA. TFP and other phospholipase A2 inhibitors were able to displace [3H]TMZ from its mitochondrial binding sites whereas CsA was ineffective. We suggest that TMZ, like TFP, inhibits the CsA insensitive mechanism involved in the swelling process which is responsible for the worsening effect observed in the presence of CsA when the swelling is generated by Ca2+ and t-BH.
Assuntos
Ciclosporina/farmacologia , Mitocôndrias Hepáticas/efeitos dos fármacos , Dilatação Mitocondrial/efeitos dos fármacos , Trimetazidina/farmacologia , Animais , Cálcio/farmacologia , Masculino , Mitocôndrias Hepáticas/fisiologia , Ratos , Ratos Wistar , Trifluoperazina/farmacologiaRESUMO
Eight days' desipramine administration (16 mg/kg per day i.p.) to rats resulted in a significant decrease in the density of beta-adrenoceptors in neuronal and astroglial cells from rat forebrain and cerebellum without modification of their corresponding affinity. beta-Adrenoceptor subtypes, beta 1 and beta 2, which coexist in neurons and astrocytes, are differently distributed in the brain and differently modified by desipramine administration which down-regulates beta 1-adrenoceptor in forebrain neurons and astrocytes and beta 2-adrenoceptor in cerebellum neurons. This down-regulation affects the predominant subtype, beta 1 or beta 2, of the relevant structure. Astroglial and neuronal beta-adrenoceptors are differently coupled to G-proteins. Only neuronal cells contain the high-affinity conformational state of the beta-adrenoceptors which is sensitive to GTP. The percentage of neuronal receptors in the high-affinity state differs according to brain area. Desipramine treatment decreases the neuronal density of both cerebellar high- and low-affinity sites and only the forebrain high-affinity site. The desipramine effects are thus subtype-dependent and differ between the two brain areas selected.
Assuntos
Inibidores da Captação Adrenérgica/farmacologia , Astrócitos/efeitos dos fármacos , Desipramina/farmacologia , Regulação para Baixo/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Receptores Adrenérgicos beta/efeitos dos fármacos , Antagonistas Adrenérgicos beta/metabolismo , Animais , Astrócitos/metabolismo , Sítios de Ligação , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Imidazóis/metabolismo , Masculino , Neurônios/metabolismo , Propanolaminas/metabolismo , Ratos , Ratos Wistar , Receptores Adrenérgicos beta/classificação , Receptores Adrenérgicos beta/metabolismoRESUMO
The influence of chronic administration of desipramine (16 mg/kg per day for 8 days) or citalopram (1 mg/kg per day for 8 days) on the serotonergic and noradrenergic stimulations of phosphoinositide hydrolysis and cyclic AMP formation was investigated in rat cerebral cortical slices. This was done by means of a prelabelling method allowing the simultaneous measurement of the accumulations of (3H) inositol phosphates ((3H)IP) and of (14C) cyclic AMP. Our results show that neither of the two drugs altered the inhibition of adenylate cyclase activity induced by serotonin1 (5-HT1) receptor agonists nor did they alter 5-HT1A and 5-HT1B receptor densities. Similarly they did not modify the stimulation of the inositol phosphate metabolism induced by 5-HT or norepinephrine (NE). Desipramine treatment decreased both beta-adrenoceptor-elicited cyclic AMP accumulation (-37%) and beta-adrenoceptor density (-29%), whereas citalopram was without effect. These results reinforce the idea that the ability of antidepressants to decrease the activity of the beta-adrenoceptor-adenylate cyclase complex is not common to all antidepressants, and provide no evidence for the involvement of 5-HT1A and/or 5-HT1B in the mechanism of action of these drugs.
Assuntos
Córtex Cerebral/metabolismo , Citalopram/farmacologia , AMP Cíclico/metabolismo , Desipramina/farmacologia , Fosfatos de Inositol/metabolismo , Animais , Córtex Cerebral/efeitos dos fármacos , Colforsina/farmacologia , Técnicas In Vitro , Masculino , Norepinefrina/metabolismo , Norepinefrina/fisiologia , Ratos , Ratos Wistar , Receptores Adrenérgicos beta/efeitos dos fármacos , Receptores de Serotonina/efeitos dos fármacos , Agonistas do Receptor de Serotonina/farmacologia , Inibidores Seletivos de Recaptação de Serotonina/farmacologia , Simpatomiméticos/farmacologiaRESUMO
The interaction of isoproterenol with beta-adrenoceptors has been investigated in astroglial and neuronal cells isolated from adult rat cerebral cortices. Using the non-selective beta-adrenergic antagonist (3H)CGP-12177 as a ligand, binding experiments revealed that both types of cells exhibit beta-adrenoceptors. However the analysis of the isoproterenol displacement curve indicated that only neuronal cells contained the high affinity conformational state of the beta-adrenoceptor.