Validación de la versión española del cuestionario Wound-QoL / Validation of the Spanish Wound-QoL Questionnaire

ANTECEDENTES Y OBJETIVOS: El Wound-QoL es un cuestionario validado para medir la calidad de vida en pacientes con heridas crónicas, que fue desarrollado originalmente para su uso en alemán. El objetivo de este estudio fue traducir el cuestionario Wound-QoL para su uso en la práctica clínica y estudios de investigación en España, así como validar esta versión. MATERIALES Y MÉTODOS: Se realizaron dos traducciones independientes del Wound-QoL, directa e inversa, a partir de la versión original en alemán, seguidas de un consenso de expertos sobre las versiones resultantes. Después de su perfeccionamiento se realizó un estudio piloto y posteriormente el estudio de validación. RESULTADOS: Se incluyó un total de 115 pacientes. La edad media fue de 69,5 (DE 14,5) años, y el 60,0% eran mujeres. La versión española del Wound-QoL mostró una excelente consistencia interna (índice alfa de Cronbach > 0,8 en todas las escalas). El análisis factorial dio como resultado las mismas escalas que la versión original. Se objetivaron características satisfactorias de la distribución de la puntuación global y de las subescalas. La validez de constructo y la validez convergente con otros resultados (calidad de vida genérica, tasa de curación) fueron satisfactorias. La gran mayoría de los pacientes consideraron que el cuestionario era una herramienta sencilla y factible. El tiempo medio necesario para completar el cuestionario fue de 5 minutos. El 99,1% de los participantes consideraron que las preguntas eran fáciles de entender y el 94,7% declaró que personal. CONCLUSIONES: La versión española del Wound-QoL muestra una excelente validez en la práctica clínica. Por lo tanto, puede ser recomendada para su uso tanto en la rutina clínica como en los ensayos

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 5 minutes. 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

Validation of the Spanish Wound-QoL Questionnaire. / Validación de la versión española del cuestionario Wound-QoL.

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.

Implantación y desarrollo de un sistema integrado de gestión de calidad según la norma ISO 9001: 2015 en un Servicio de Dermatología / Implementation and Operation of an Integrated Quality Management System in Accordance With ISO 9001: 2015 in a Dermatology Department

Los sistemas de gestión de calidad (SGC) son herramientas que sirven para estructurar, controlar y mejorar las actividades habituales que se desarrollan en una organización o servicio. La norma ISO 9001:2015 es una norma reconocida internacionalmente que proporciona los recursos necesarios para ayudar a una organización a mejorar su rendimiento, basándose en el principio de planificar-hacer-controlar-actuar, con el fin de obtener una mejora continua. En sanidad es una herramienta clave para la gestión de los servicios ofrecidos a los pacientes. La certificación de calidad ISO permite demostrar el cumplimiento de dicha norma, de acuerdo a unos estándares de calidad establecidos. El proceso de implantación de un SGC siguiendo esta norma debe seguir varias fases, que culminan con la realización de una auditoría externa que, una vez superada, permite obtener la certificación de calidad ISO 9001:2015. En este artículo se describen los pasos a seguir para obtener dicha certificación en un Servicio de Dermatología

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

Implementation and Operation of an Integrated Quality Management System in Accordance With ISO 9001:2015 in a Dermatology Department. / Implantación y desarrollo de un sistema integrado de gestión de calidad según la norma ISO 9001:2015 en un Servicio de Dermatología.

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.

Ampliando el perfil genético del síndrome de Hay-Wells / Expanding the genetic profile of Hay-Wells síndrome

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Long-term outcome of anemic lower-risk myelodysplastic syndromes without 5q deletion refractory to or relapsing after erythropoiesis-stimulating agents.

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.

High response rate and improved exercise capacity and quality of life with a new regimen of darbepoetin alfa with or without filgrastim in lower-risk myelodysplastic syndromes: a phase II study by the GFM.

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.

Ferritin level at diagnosis is not correlated with poorer survival in non RBC transfusion dependent lower risk de novo MDS.

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.

Nodular osteochondrogenic activity in soft tissue surrounding osteoma in neurogenic para osteo-arthropathy: morphological and immunohistochemical study.

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.

Attenuation of liver normothermic ischemia--reperfusion injury by preservation of mitochondrial functions with S-15176, a potent trimetazidine derivative.

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.

S-15176 reduces the hepatic injury in rats subjected to experimental ischemia and reperfusion.

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.

[(3)H]-trimetazidine mitochondrial binding sites: regulation by cations, effect of trimetazidine derivatives and other agents and interaction with an endogenous substance.

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.

Evidence for different interactions between beta(1)- and beta(2)-adrenoceptor subtypes with adenylyl cyclase in the rat brain: a concentration-response study using forskolin.

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.

Dose-related inversion of cinnarizine and flunarizine effects on mitochondrial permeability transition.

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.

Trimetazidine counteracts the hepatic injury associated with ischemia-reperfusion by preserving mitochondrial function.

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.

Evidence for the existence of [3H]-trimetazidine binding sites involved in the regulation of the mitochondrial permeability transition pore.

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.

A match between binding to beta-adrenoceptors and stimulation of adenylyl cyclase parameters of (-)isoproterenol and salbutamol on rat brain.

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.

Comparison of the effects of cyclosporine A and trimetazidine on Ca(2+)-dependent mitochondrial swelling.

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.

Characterization of beta-adrenergic receptors of freshly isolated astrocytes and neurons from rat brain.

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.