RESUMO
OBJECTIVES: This study aims to identify if wintertime surgery increases the mortality of the patients after hip fracture operations. DESIGN: Retrospective observational cohort study. SETTING: The data for this citywide retrospective observational cohort study came from Clinical Data Analysis Reporting System. PATIENT: This study included 35 409 patients with hip fracture operations from July 2005 to December 2013. MAIN OUTCOME MEASURES: Cox regression hazard model was used to estimate the independent effect of operation being performed in winter on the hazard of mortality. The hazard model included covariates found to be independent predictors of mortality: age, sex, surgical delay, and Charlson Comorbidity Index (CCI). RESULTS: There was a seasonal variation with more hip fracture operations happening in the winter months. The 1-month, 6-month, 1-year, and 5-year mortality were 3%, 11%, 17%, and 47%, respectively. Operation performed in winter was associated with a higher hazard of mortality (hazard ratio [HR] 1.040; 95% confidence interval: 1.010-1.072; P = .009). The HR was greater with male sex (HR 1.786; P = .000), advanced age (≥85 years old: HR 2.819; P = .000), the longer surgical delay (HR 1.018; P = .000), and higher CCI (severe CCI group: HR 2.963; P = .000). CONCLUSION: Wintertime hip fracture surgery was associated with an increased hazard of mortality after adjusting for other known risk factors affecting mortality post hip fracture operations.
RESUMO
Rotational malalignment during femoral nailing is common despite having various intraoperative assessment methods. The cortical step sign and diameter difference sign (CSSDDS) is commonly used because of convenience, yet it lack proper scientific scrutiny and is thought to be error prone. Using a software algorithm, cross-sectional dimensions were obtained from CT scans of 22 intact adult femurs at the proximal, mid and distal diaphysis. With multiple simulated scenarios the sensitivity of CSSDDS was comprehensively determined at all possible C-arm positions. At rotation, cortical width changed most significantly around the thick linea aspera and femoral diameter changed most significantly at the sagittal plane. At 15 degrees of rotation and with the linea aspera in view, CSSDDS thresholds of 0.3mm, 0.6mm and 1mm had sensitivities of 98.8%, 93.1% and 73.8%. With the linea aspera masked behind the femur and out of view, the sensitivities significantly deteriorated to 96.4%, 77.1% and 44.1% respectively. CSSDDS is sufficiently sensitive only when strict rules are followed. It is imperative that the operator position the image intensifier in lateral view under proper magnification so that steps of less than 0.6mm around the linea aspera may be appreciated.
Assuntos
Diáfises/diagnóstico por imagem , Fraturas do Fêmur/diagnóstico por imagem , Fêmur/diagnóstico por imagem , Fixação Interna de Fraturas/métodos , Fraturas Mal-Unidas/diagnóstico por imagem , Algoritmos , China , Diáfises/anatomia & histologia , Diáfises/patologia , Fraturas do Fêmur/patologia , Fraturas do Fêmur/cirurgia , Fêmur/anatomia & histologia , Fêmur/patologia , Fraturas Mal-Unidas/patologia , Humanos , Exame Físico , Reprodutibilidade dos Testes , Estudos Retrospectivos , Rotação , Software , Tomografia Computadorizada por Raios XRESUMO
The spiral blade modification of the Dynamic Hip Screw (DHS) was designed for superior biomechanical fixation in the osteoporotic femoral head. Our objective was to compare clinical outcomes and in particular the incidence of loss of fixation. In a series of 197 consecutive patients over the age of 50 years treated with DHS-blades (blades) and 242 patients treated with conventional DHS (screw) for AO/OTA 31.A1 or A2 intertrochanteric fractures were identified from a prospectively compiled database in a level 1 trauma centre. Using propensity score matching, two groups comprising 177 matched patients were compiled and radiological and clinical outcomes compared. In each group there were 66 males and 111 females. Mean age was 83.6 (54 to 100) for the conventional DHS group and 83.8 (52 to 101) for the blade group. Loss of fixation occurred in two blades and 13 DHSs. None of the blades had observable migration while nine DHSs had gross migration within the femoral head before the fracture healed. There were two versus four implant cut-outs respectively and one side plate pull-out in the DHS group. There was no significant difference in mortality and eventual walking ability between the groups. Multiple logistic regression suggested that poor reduction (odds ratio (OR) 11.49, 95% confidence intervals (CI) 1.45 to 90.9, p = 0.021) and fixation by DHS (OR 15.85, 95%CI 2.50 to 100.3, p = 0.003) were independent predictors of loss of fixation. The spiral blade design may decrease the risk of implant migration in the femoral head but does not reduce the incidence of cut-out and reoperation. Reduction of the fracture is of paramount importance since poor reduction was an independent predictor for loss of fixation regardless of the implant being used. Cite this article: Bone Joint J 2015;97-B:398-404.
Assuntos
Parafusos Ósseos/efeitos adversos , Migração de Corpo Estranho/diagnóstico , Fixação Interna de Fraturas/instrumentação , Fraturas do Quadril/etiologia , Fraturas do Quadril/cirurgia , Osteoporose/complicações , Idoso , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos , Estudos de Casos e Controles , Avaliação da Deficiência , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Pontuação de Propensão , Desenho de Prótese , Recuperação de Função Fisiológica , Estudos Retrospectivos , Fatores de Risco , Resultado do TratamentoRESUMO
PURPOSE: To assess the effect of hyaluronic acid instillation after arthroscopic anterior cruciate ligament (ACL) reconstruction for improving pain, range of movement, and function of the knee. METHODS: 28 men and 4 women underwent arthroscopic ACL reconstruction for isolated ACL rupture (partial or complete) and instability after recreational sports injury 2 to 120 months earlier. They were randomised to undergo arthroscopic ACL reconstruction followed by intra-articular viscoseal instillation (13 men and 3 women) or arthroscopic ACL reconstruction alone (15 men and 1 woman). The knee injury osteoarthritis outcome score (for pain, symptoms, activities of daily living, sport and recreation function, and quality of life), range of movement, knee circumference, and analgesic use were assessed on days -1, 1, and 2, and weeks 2, 6 and 12. RESULTS: Patient demographics were similar at baseline. At postoperative days 1 and 2, all subscales of the knee injury osteoarthritis outcome score (except for quality of life) were significantly higher in the viscoseal group. At weeks 2, 6, and 12, improvement in both groups equalised. Knee swelling (change in knee circumference) was significantly less in the viscoseal group at days 1 and 2 (p=0.009 and p=0.038, respectively, Mann-Whitney U test). Only one patient in the viscoseal group had a limited range of movement. No patient developed any adverse reaction. CONCLUSION: Intra-articular viscoseal instillation improved pain control and swelling 2 days after arthroscopic ACL reconstruction.
Assuntos
Reconstrução do Ligamento Cruzado Anterior/métodos , Artroscopia , Ácido Hialurônico/administração & dosagem , Viscossuplementos/administração & dosagem , Adulto , Método Duplo-Cego , Feminino , Humanos , Instilação de Medicamentos , Masculino , Cuidados Pós-OperatóriosRESUMO
BACKGROUND AND OBJECTIVE: Porphyromonas gingivalis lipopolysaccharide (LPS) is a ligand for cell surface toll-like receptors (TLR), TLR2 and TLR4 while stimulation of either leads to cardioprotection. We hypothesized that: (1) pretreatment with P. gingivalis LPS at appropriate concentrations would induce cardioprotection against injury induced by ischemia and reperfusion; and (2) P. gingivalis LPS pretreatment at cardioprotective concentrations may reduce Ca(2+) overload, which is a precipitating cause of injury, and improve recovery of contractile function. MATERIAL AND METHODS: Male Sprague-Dawley rats were randomly selected to receive intraperitoneal saline or hot phenol-water-extracted P. gingivalis LPS at 0.2, 0.5, 1.0, 2.0 or 4.0 mg/kg 24 h before the experiment. The hearts were isolated and subjected to regional ischemia by coronary artery ligation followed by reperfusion. In isolated rat ventricular myocytes, the cytosolic Ca(2+) level and the electrically induced intracellular calcium (E[Ca(2+)](i)) transient, which reflects contractile function, were determined after pretreatment with a cardioprotective dose of P. gingivalis LPS. RESULTS: Pretreatment with 0.5 mg/kg P. gingivalis LPS significantly reduced, while pretreatment with 1.0-4.0 mg/kg significantly increased infarct size. The Ca(2+) overload induced by ischemia-reperfusion was attenuated in myocytes from rats pretreated with 0.5 mg/kg P. gingivalis LPS. Pretreated myocytes also showed an increased amplitude of the E[Ca(2+)](i) transient, no prolongation of the time to reach the peak E[Ca(2+)](i) transient and shorter 50% decay time during reperfusion. CONCLUSION: At a dosage of 0.5 mg/kg, P. gingivalis LPS confers cardioprotection against ischemia-reperfusion-induced injury and improved intracellular E[Ca(2+)](i) transient recovery, hence improving myocyte contractile recovery.
Assuntos
Sinalização do Cálcio/efeitos dos fármacos , Cardiotônicos/uso terapêutico , Precondicionamento Isquêmico Miocárdico/métodos , Lipopolissacarídeos/uso terapêutico , Porphyromonas gingivalis , Potenciais de Ação/efeitos dos fármacos , Animais , Cálcio/análise , Canais de Cálcio/efeitos dos fármacos , Cardiotônicos/administração & dosagem , Citosol/efeitos dos fármacos , Ventrículos do Coração/patologia , Injeções Intraperitoneais , Lipopolissacarídeos/administração & dosagem , Masculino , Contração Miocárdica/efeitos dos fármacos , Infarto do Miocárdio/prevenção & controle , Isquemia Miocárdica/patologia , Isquemia Miocárdica/fisiopatologia , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Miócitos Cardíacos/efeitos dos fármacos , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Recuperação de Função Fisiológica/efeitos dos fármacos , Sarcolema/efeitos dos fármacos , Retículo Sarcoplasmático/efeitos dos fármacos , Fatores de TempoRESUMO
BACKGROUND AND PURPOSE: Oestrogen confers cardioprotection by down-regulating the beta(1)-adrenoceptor and suppressing the expression and activity of protein kinase A. We hypothesized that oestrogen may also protect the heart by suppressing Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), another signalling messenger activated by the beta(1)-adrenoceptor, that enhances apoptosis. EXPERIMENTAL APPROACH: We first determined the expression of CaMKII in the heart from sham and ovariectomized rats with and without oestrogen replacement. We then determined the effects of CaMKII inhibition (KN93, 2.5 micromolxL(-1)) in the presence or absence of 10(-7) molxL(-1) isoprenaline, a non-selective beta-adrenoceptor agonist. We also determined the percentage apoptosis in myocytes from rats in each group with or without beta-adrenoceptor stimulation. KEY RESULTS: Both CaMKIIdelta and phosphorylated CaMKII were up-regulated in the hearts from ovariectomized rats, and they were restored to normal by oestrogen replacement. The infarct size and lactate dehydrogenase release were significantly greater after ovariectomy. Similarly, cardiac contractility, the amplitude of the electrically induced intracellular Ca(2+) transient and the number of apoptotic cells were also greater in ovariectomized rats upon ischaemia/reperfusion in the presence or absence of isoprenaline. Most importantly, the responses to ischaemic insult in ovariectomized rats were reversed not only by oestrogen replacement, but by blockade of CaMKII with KN93. CONCLUSIONS AND IMPLICATIONS: Oestrogen confers cardioprotection at least partly by suppressing CaMKIIdelta. This effect of oestrogen on CaMKII is independent of the beta-adrenoceptor and occurs in addition to down-regulation of the receptor.
Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Estrogênios/metabolismo , Infarto do Miocárdio/prevenção & controle , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Miócitos Cardíacos/enzimologia , Agonistas Adrenérgicos beta/farmacologia , Animais , Apoptose , Benzilaminas/farmacologia , Sinalização do Cálcio , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/antagonistas & inibidores , Células Cultivadas , Modelos Animais de Doenças , Regulação para Baixo , Implantes de Medicamento , Estrogênios/administração & dosagem , Estrogênios/sangue , Feminino , Isoproterenol/farmacologia , Contração Miocárdica , Infarto do Miocárdio/enzimologia , Infarto do Miocárdio/fisiopatologia , Traumatismo por Reperfusão Miocárdica/enzimologia , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/patologia , Ovariectomia , Fosforilação , Inibidores de Proteínas Quinases/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores Adrenérgicos beta/metabolismo , Recuperação de Função Fisiológica , Sulfonamidas/farmacologiaRESUMO
BACKGROUND AND PURPOSE: Testosterone alleviates symptoms in patients with ischaemic heart disease. Androgen receptors are present in the heart, and testosterone upregulates gene expression of cardiac beta(1)-adrenoceptors. We hypothesize that testosterone may confer cardioprotection by interacting with adrenoceptors. EXPERIMENTAL APPROACH: In isolated perfused hearts and ventricular myocytes from orchidectomized rats without or with testosterone (200 microg/100 g) replacement, we first determined the effect of ischaemia/reperfusion in the presence of noradrenaline (10(-7) M). Then we determined the contribution of interactions between testosterone and alpha(1)- or beta(1)-adrenoceptors in cardiac injury/protection (infarct size, release of lactate dehydrogenase, viability of myocytes, recovery of contractile function and incidence of arrhythmias) upon ischaemia/reperfusion by pharmacological manipulation using selective adrenoceptor agonists (alpha(1)-adrenoceptor agonist: phenylephrine 10(-6) M; non-selective beta-adrenoceptor agonist: isoprenaline 10(-7) M) and antagonists (alpha(1): prazosin or benoxathian 10(-6) M; beta(1): CGP 20712A 5 x 10(-7) M). We also determined the expression of alpha(1) and beta(1)-adrenoceptor in the hearts from rats with and without testosterone. KEY RESULTS: Testosterone reduced injury induced by ischaemia/reperfusion and noradrenaline. This was achieved by enhancing the beneficial effect of alpha(1)-adrenoceptor stimulation, which was greater than the deleterious effect of beta(1)-adrenoceptor stimulation (also enhanced by testosterone). The effects of testosterone were abolished or attenuated by blockade of androgen receptors. Testosterone also enhanced the expression of alpha(1A) and beta(1)-adrenoceptor. CONCLUSIONS AND IMPLICATIONS: Testosterone conferred cardioprotection by upregulating the cardiac alpha(1)-adrenoceptor and enhancing the effects of stimulation of this adrenoceptor. The effect of testosterone was at least partly mediated by androgen receptors.
Assuntos
Agonistas Adrenérgicos/metabolismo , Miócitos Cardíacos/metabolismo , Norepinefrina/metabolismo , Orquiectomia , Receptores Adrenérgicos alfa 1/metabolismo , Receptores Androgênicos/metabolismo , Traumatismo por Reperfusão/prevenção & controle , Testosterona/metabolismo , Agonistas Adrenérgicos/administração & dosagem , Antagonistas Adrenérgicos/farmacologia , Antagonistas de Androgênios/farmacologia , Animais , Arritmias Cardíacas/metabolismo , Arritmias Cardíacas/prevenção & controle , Sobrevivência Celular , Acetato de Ciproterona/farmacologia , Modelos Animais de Doenças , L-Lactato Desidrogenase/metabolismo , Masculino , Contração Miocárdica , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/prevenção & controle , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/patologia , Norepinefrina/administração & dosagem , Ratos , Ratos Sprague-Dawley , Receptor Cross-Talk , Receptores Adrenérgicos alfa 1/efeitos dos fármacos , Receptores Adrenérgicos beta 1/metabolismo , Receptores Adrenérgicos beta 2/metabolismo , Receptores Androgênicos/efeitos dos fármacos , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/patologia , Traumatismo por Reperfusão/fisiopatologia , Testosterona/administração & dosagem , Testosterona/sangue , Fatores de Tempo , Regulação para Cima , Função Ventricular EsquerdaRESUMO
Intravenous pretreatment with kappa-opioid receptor antagonist (-)-U-50,488 (1 mg/kg) improved heart resistance to the arrhythmogenic effect of coronary occlusion and reperfusion. Selective kappa1-opioid receptor antagonist norbinaltorphimine and nonselective blocker of peripheral opioid receptors methylnaloxone abolished this antiarrhythmic effect. Preliminary blockade of protein kinase C with chelerythrine or inhibition of ATP-dependent K+ channels (K(ATP) channels) with glybenclamide abolished the antiarrhythmic effect of kappa-opioid receptor activation. Selective inhibitor of sarcolemmal K(ATP) channels did not modulate the kappa-opioid receptor-mediated increase in cardiac electrical stability. Our results suggest that protein kinase C and mitochondrial K(ATP) channels play an important role in the antiarrhythmic effect associated with activation of peripheral kappa-opioid receptors.
Assuntos
(trans)-Isômero de 3,4-dicloro-N-metil-N-(2-(1-pirrolidinil)-ciclo-hexil)-benzenoacetamida/farmacologia , Arritmias Cardíacas/prevenção & controle , Receptores Opioides kappa/agonistas , (trans)-Isômero de 3,4-dicloro-N-metil-N-(2-(1-pirrolidinil)-ciclo-hexil)-benzenoacetamida/administração & dosagem , Alcaloides/administração & dosagem , Alcaloides/farmacologia , Animais , Antiarrítmicos/administração & dosagem , Antiarrítmicos/farmacologia , Arritmias Cardíacas/etiologia , Arritmias Cardíacas/fisiopatologia , Benzofenantridinas/administração & dosagem , Benzofenantridinas/farmacologia , Glibureto/administração & dosagem , Glibureto/farmacologia , Masculino , Traumatismo por Reperfusão Miocárdica/complicações , Naltrexona/administração & dosagem , Naltrexona/análogos & derivados , Naltrexona/farmacologia , Oximorfona/administração & dosagem , Oximorfona/farmacologia , Canais de Potássio/fisiologia , Proteína Quinase C/antagonistas & inibidores , Proteína Quinase C/metabolismo , Ratos , Ratos Wistar , Receptores Opioides kappa/antagonistas & inibidores , Receptores Opioides kappa/fisiologiaRESUMO
BACKGROUND: Preconditioning with remifentanil (RPC) provides immediate cardioprotection in rats via all three types of opioid (OP) receptor. This study sought to investigate whether remifentanil also confers delayed cardioprotection via OP receptors. METHODS: Male rats received preconditioning either by ischaemia (IPC; 5 min occlusion, 5 min reperfusion x 3) or with remifentanil (RPC; 1, 5, 10, and 20 microg kg(-1) min(-1), 20 min infusion). After 24 h, all animals were subjected to 30 min occlusion of the left coronary artery and 2 h of reperfusion. Subsequently, the time-course effect of RPC (10 microg kg(-1) min(-1), 20 min infusion) was determined at 12, 16, 24, 32, 36, and 48 h intervals, using the same experimental procedure. The effect of RPC (10 microg kg(-1) min(-1), 20 min infusion) and IPC in the presence of selective OP receptor antagonists was evaluated at the 24 h interval. Infarct size (IS), as a percentage of the area at risk (AAR), was determined. RESULTS: Pre-treatment with remifentanil at 1, 5, 10, and 20 microg kg(-1) min(-1) significantly reduced the IS/AAR at 24 h with the maximum effect at 10 microg kg(-1) min(-1). Remifentanil at 10 microg kg(-1) min(-1) significantly reduced the IS at 12 h [32.5 (sd 9.1)%]; 16 h [26.1 (2.8)%]; 24 h [19.5 (5.0)%]; 32 h [31.2 (9.1)%]; and 36 h [36.4 (9.4)%] after drug administration. The maximal reduction in IS was seen at 24 h and the effect completely disappeared at 48 h [36.4 (9.4)%]. The protective effect of RPC was abolished or significantly attenuated by blockade of any of the three OP receptors with selective antagonists. CONCLUSIONS: Like IPC, remifentanil produces delayed cardioprotection in anaesthetized rats 12-36 h after administration. The protective effect is mediated via all three OP receptors.
Assuntos
Analgésicos Opioides/uso terapêutico , Precondicionamento Isquêmico Miocárdico/métodos , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Piperidinas/uso terapêutico , Animais , Pressão Sanguínea/efeitos dos fármacos , Relação Dose-Resposta a Droga , Esquema de Medicação , Avaliação Pré-Clínica de Medicamentos , Frequência Cardíaca/efeitos dos fármacos , Masculino , Infarto do Miocárdio/patologia , Infarto do Miocárdio/prevenção & controle , Antagonistas de Entorpecentes , Ratos , Ratos Sprague-Dawley , Receptores Opioides/fisiologia , Remifentanil , Fatores de Tempo , Resultado do TratamentoRESUMO
Pretreatment with a selective kappa1 opioid receptor (OR) agonist (-)-U-50,488 (1 mg/kg, i.v.) prevented the development of arrhythmias induced by occlusion (10 min) and reperfusion (10 min) in ketamine anesthetized rats, while the treatment with a less active enantiomer (+)-U-50,488 in the same dose produced no such effects. Preliminary intravenous administration of a selective kappa1 OR antagonist norbinaltorphimine (9 mg/kg) fully abolished the antiarrhythmic effect of (-)-U-50,488, while the kappa2 OR antagonist quadazocine (3 mg/kg) did not eliminate this effect. The injections of norbinaltorphimine or quadazocine alone did not influence the incidence of model arrhythmias caused by the occlusion and reperfusion. It was concluded that kappa1 OR stimulation favors an increase in cardiac tolerance to the arrhythmogenic action of occlusion and reperfusion.
Assuntos
(trans)-Isômero de 3,4-dicloro-N-metil-N-(2-(1-pirrolidinil)-ciclo-hexil)-benzenoacetamida/administração & dosagem , Anti-Hipertensivos/administração & dosagem , Arritmias Cardíacas/tratamento farmacológico , Naltrexona/análogos & derivados , Receptores Opioides kappa/agonistas , Animais , Isquemia Miocárdica/metabolismo , Reperfusão Miocárdica , Naltrexona/administração & dosagem , Antagonistas de Entorpecentes/administração & dosagem , Ratos , Ratos WistarRESUMO
PURPOSE: To correlate the radiographic measurement, cord diameter shown on magnetic resonance imaging (MRI), and clinical hand sign of cervical myelopathic patients. METHODS: Patients with clinical cervical myelopathy who had had MRI in Kwong Wah Hospital between January 2001 and December 2002 were enlisted. Their cervical spine radiographs and clinical records were reviewed. RESULTS: Of 36 patients with a complete set of MRI films, cervical spine radiographs, and clinical notes; 18% did not have Hoffman's sign, 47% had normal supinator reflex, 39% had unimpaired 10-second test, and 45% showed no finger escape sign. The presence of myelopathic hand signs was not correlated to any radiological assessment, cord diameter, or presence of myelomalacia at any level. CONCLUSION: Cervical spine radiography cannot predict the level and degree of cervical spinal cord compression. Myelopathic hand signs are not diagnostically fail-safe and cannot predict the level and degree of cord compression.
Assuntos
Vértebras Cervicais , Imageamento por Ressonância Magnética , Compressão da Medula Espinal/diagnóstico , Tomografia Computadorizada por Raios X , Adulto , Idoso , Idoso de 80 Anos ou mais , Distribuição de Qui-Quadrado , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Curva ROC , Compressão da Medula Espinal/diagnóstico por imagemRESUMO
Since cold exposure confers cardioprotection, the present study attempted to determine the role of opioid receptors (OR). Stress with cold exposure and restraint for 3 h, shown previously to induce peptic ulcer in a synergistic manner, attenuated infarct size induced by myocardial ischemia and reperfusion in the isolated perfused rat heart from 36.64 +/- 1.8 to 22.85 +/- 2.6%. This is similar to protecting the rat with morphine at 8 mg/kg, which also attenuated the infarct size from 36.26 +/- 1.6 to 20.30 +/- 2.1%. The effects of cold-restraint or morphine were abolished by naloxone, a non-selective OR antagonist; nor-binaltorphimine, a selective kappa-OR antagonist; naltrindole, a selective delta-OR antagonist, or CTOP, a selective mu-OR antagonist. The effects were also attenuated by blockade of protein kinase C or the mitochondrial K(ATP) channel. The finding is first evidence that all three OR subtypes mediate cardioprotection of cold-restraint stress in the rat.
Assuntos
Coração/efeitos dos fármacos , Coração/fisiologia , Morfina/farmacologia , Infarto do Miocárdio/prevenção & controle , Miocárdio/metabolismo , Naltrexona/análogos & derivados , Canais de Potássio/química , Receptores Opioides/fisiologia , Somatostatina/análogos & derivados , Trifosfato de Adenosina/química , Animais , Temperatura Baixa , Morfina/química , Isquemia Miocárdica , Naloxona/farmacologia , Naltrexona/farmacologia , Antagonistas de Entorpecentes , Perfusão , Potássio/química , Proteína Quinase C/química , Proteína Quinase C/metabolismo , Ratos , Receptores Opioides kappa/química , Traumatismo por Reperfusão , Somatostatina/farmacologia , Estresse Fisiológico , Fatores de TempoRESUMO
In this study, we determined the effects of an extract of Radix Stephaniae Tetrandrae (RST) on arterial blood pressure and heart weight in deoxycorticosterone acetate-salt (DOCA-salt) hypertensive rats. We also determined the effects of the extract on arrhythmia and infarct induced by myocardial ischaemia and reperfusion in anaesthetized rats. We further compared the effects of the extract with those of tetrandrine, which makes up 7% of the extract and is known to act as a calcium-channel antagonist, and verapamil, a prototype calcium-channel antagonist. Treatment with RST extract returned the arterial blood pressure, cardiac compliance and coronary flow towards normal, and reduced right ventricular hypertrophy in the DOCA-salt hypertensive rat. In the anaesthetized rat, the RST extract reduced arrhythmia and infarct size induced by myocardial ischaemia and reperfusion; the effects were similar to those of tetrandrine and verapamil. The findings indicate that the RST extract acts like a calcium-channel antagonist. It may be used in the treatment of cardiovascular diseases, as are the calcium-channel antagonist and tetrandrine. More interestingly, the effects of the RST extract were of the same potency as tetrandrine. Since only 7% of the extract was tetrandrine, the observation indicates that tetrandrine was not the only component that was responsible for the actions of the extract.
Assuntos
Arritmias Cardíacas/tratamento farmacológico , Medicamentos de Ervas Chinesas/uso terapêutico , Hipertensão/tratamento farmacológico , Fitoterapia , Stephania tetrandra , Alcaloides/uso terapêutico , Animais , Arteriopatias Oclusivas/complicações , Benzilisoquinolinas/uso terapêutico , Bloqueadores dos Canais de Cálcio/uso terapêutico , Doença da Artéria Coronariana/complicações , Masculino , Infarto do Miocárdio/etiologia , Infarto do Miocárdio/prevenção & controle , Traumatismo por Reperfusão Miocárdica/etiologia , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Raízes de Plantas , Ratos , Ratos Sprague-Dawley , Verapamil/uso terapêuticoRESUMO
AIMS/HYPOTHESIS: The aim of this study was to determine the effects of preconditioning on injury and expression of heat shock proteins 70 in diabetic rat hearts. METHODS: Diabetes was induced by an intraperitoneal injection of 65 mg kg(-1) streptozotocin. Daily subcutaneous injection of 4 IU insulin started 2 weeks after streptozotocin treatment for 4 weeks. Rats were preconditioned by intravenous injection of 10 mg kg(-1) U50,488H, a selective kappa-opioid receptor agonist (U50,488H preconditioning). The effects of U50,488H preconditioning had previously been shown to be blocked by a selective kappa-opioid receptor antagonist, nor-binaltorphimine. Twenty-four hours later, rats were subjected to 30 min of regional ischaemia by occlusion of the left coronary artery followed by 4 h of reperfusion. Infarct size was determined at the end of reperfusion. Stress-inducible and constitutive heat shock proteins 70 were analysed at the end of ischaemia and reperfusion by Western blotting. RESULTS: Myocardial infarcts induced by ischaemia and reperfusion were greater in diabetic rats. U50,488H preconditioning significantly reduced the infarct size and increased the expression of stress-inducible heat-shock protein 70 in normal rats. The effects of U50,488H preconditioning were abolished in streptozotocin-induced diabetic rats, but restored by insulin replacement. CONCLUSION/INTERPRETATION: In addition to a greater susceptibility to ischaemic insults, the delayed cardioprotection of U50,488H preconditioning was lost, which could at least partly be due to impaired synthesis of stress-inducible heat-shock protein 70 in diabetic rats.
Assuntos
Cardiotônicos/farmacologia , Diabetes Mellitus Experimental/fisiopatologia , Proteínas de Choque Térmico HSP70/metabolismo , Isquemia Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Receptores Opioides kappa/antagonistas & inibidores , (trans)-Isômero de 3,4-dicloro-N-metil-N-(2-(1-pirrolidinil)-ciclo-hexil)-benzenoacetamida/farmacologia , Animais , Glicemia/análise , Glicemia/efeitos dos fármacos , Western Blotting , Peso Corporal/efeitos dos fármacos , Diabetes Mellitus Experimental/metabolismo , Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico HSC70 , Coração/efeitos dos fármacos , Coração/fisiopatologia , Insulina/farmacologia , Masculino , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Miocárdio/metabolismo , Miocárdio/patologia , Tamanho do Órgão/efeitos dos fármacos , Ratos , Ratos Sprague-DawleyRESUMO
In the present study, we determined whether interleukin-2 (IL-2) confers cardioprotection by inhibiting mitochondria permeability transition pore (MPTP) opening. In isolated rat hearts subject to 30 min ischemia and 120 min reperfusion (IR), IL-2 (50 U/ml) decreased the infarct size and LDH release, effects blocked by a selective kappa-opioid receptor antagonist, Nor-BNI (5 microM) or an opener of MPTP, atractyloside (Atr, 20 microM). In isolated ventricular myocytes subjected to anoxia and reoxygenation (AR), which reduced both the amplitude of the electrically induced [Ca2+]i transient and diastolic [Ca2+]i, IL-2 attenuated the AR-induced alterations and their effects were abolished by Atr. In addition, IL-2 attenuated the reduction in calcein fluorescence in myocytes subject to AR and reduced calcium-induced swelling in mitochondria of rat hearts subjected to IR, which were similar to effect of inhibitor of MPTP. The observations indicated that IL-2 confers cardioprotection by inhibiting the MPTP opening.
RESUMO
1. The effects of pharmacological preconditioning with U50488H (U(50)), a selective kappa-opioid receptor agonist, on Ca(2+) homeostasis in rat ventricular myocytes subjected for 9 min to metabolic inhibition (MI) and anoxia (A), consequences of ischaemia, were studied and compared with those of preconditioning with brief periods of MI/A. 2. Precondition with 30 micro M of U(50) for three cycles of 1 min each cycle separated by 3 min of recovery (UP) significantly increased the percentage of non-blue cells following MI/A. The effect of UP is the same as that of preconditioning with an inhibitor of glycolysis and an oxygen scavenger for three 1-min cycles separated by three-minute recovery (MI/AP). The results indicate that like MI/AP, UP also confers cardioprotection. 3. MI/A increased intracellular Ca(2+) ([Ca(2+)](i)) and reduced the amplitude of caffeine-induced [Ca(2+)](i) transients, an indication of Ca(2+) content in the sarcoplasmic reticulum (SR). MI/A also reduced the electrically-induced [Ca(2+)](i) transient, that indicates Ca(2+)-release during excitation-contraction coupling, and Ca(2+) sparks in unstimulated myocytes, that indicates spontaneous Ca(2+)-release from SR. It also prolonged the decline of the electrically-induced [Ca(2+)](i) transient and slowed down the recovery of the electrically-induced [Ca(2+)](i) transient after administration of caffeine. In addition, MI/A prolonged the decline of caffeine induced [Ca(2+)](i) transient, an indication of Na(+)-Ca(2+) exchange activity, and UP prevented it. So UP, that confers cardioprotection, prevented the changes induced by MI/A. With the exception of Ca(2+)-spark, which was not studied, the effects of MI/AP are the same as those of UP. 4. It is concluded that pharmacological preconditioning with U(50), that confers immediate cardioprotection, prevents changes of Ca(2+) homeostasis altered by MI/A in the rat heart. This may be responsible, at least partly, for the cardioprotective action. 5. The study also provided evidence that MI/A causes mobilization of Ca(2+) from SR to cytoplasm causing Ca(2+)-overload which may be due to reduced Ca(2+)-uptake by SR. MI/A also reduces spontaneous and electrically induced Ca(2+) release from SR.
Assuntos
(trans)-Isômero de 3,4-dicloro-N-metil-N-(2-(1-pirrolidinil)-ciclo-hexil)-benzenoacetamida/farmacologia , Cálcio/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Animais , Cafeína/farmacologia , Hipóxia Celular/fisiologia , Desoxiglucose/farmacologia , Estimulação Elétrica , Ventrículos do Coração/citologia , Ventrículos do Coração/efeitos dos fármacos , Ventrículos do Coração/metabolismo , Homeostase/efeitos dos fármacos , Masculino , Miócitos Cardíacos/citologia , Miócitos Cardíacos/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores Opioides kappa/agonistas , Fatores de TempoRESUMO
AIM: The responses of the intracellular calcium ([Ca2+]i) and the intracellular pH (pHi) to kappa-opioid receptor stimulation were determined in the single right ventricular myocytes isolated from the hearts of chronically hypoxic rats which exhibited right ventricular hypertrophy (RVH). METHODS: With the spectrofluorometric method, the electrically-induced [Ca2+]i transient and pHi were measured in myocytes loaded with fura-2 and BCECF [2',7'-bis-(2-carboxyethyl)-5-(and 6)-carboxyfluorscein], respectively. RESULTS: U50,488H, a selective kappa-opioid agonist decreased the electrically-induced [Ca2+]i transient and increased the pHi. The effect of U50,488H was mediated by protein kinase C (PKC). In the RVH, the effect of U50,488H on the [Ca2+]i transient and the pHi were significantly attenuated. In parallel, 4-phorbol 12-myristate 13-acetate (PMA), an activator of PKC, also decreased the [Ca2+]i transient and increased the pHi. In the RVH, the effects of PMA were blunted. The recovery of pHi, which was blocked by ethylisopropyl-amiloride (EIPA), following an acid loading induced by washout of 10 mmol/L NH4)Cl exposing to the cells for 10 min was the same in the RVH and control myocytes. CONCLUSION: kappa-Opioid receptor signaling was impaired in the cardiac hypertrophy due to a defect in the coupling of PKC signaling with its effector.
Assuntos
Cálcio/metabolismo , Cardiomegalia/fisiopatologia , Receptores Opioides kappa/fisiologia , Transdução de Sinais , Animais , Masculino , Miocárdio/patologia , Proteína Quinase C/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
Kappa-opioid receptor (OR) stimulation with a selective agonist, U50,488H (U50), known to mediate the delayed cardioprotection of metabolic inhibition preconditioning (MIP) against cell injury/death in rat ventricular myocytes, has been shown to act via protein kinase C (PKC). We attempted to identify the PKC isoform(s) that is activated, thus triggering delayed cardioprotection of MIP and pretreatment with 10 microM U50 (U50 pretreatment, UP). Release of lactate dehydrogenase and exclusion of trypan blue by isolated rat ventricular myocytes were used as indices of cell injury and death, respectively. Both MIP and UP induced translocation of PKC-epsilon, but not other PKC isoforms, -alpha and -delta, from cytosolic to membrane fractions. This was accompanied by reductions in cell injury/death induced by lethal simulated ischemia. The effects of MIP and UP were attenuated and abolished by 1 microM nor-binaltorphimine, a selective kappa-OR antagonist, administered before and during preconditioning/pretreatment, respectively. The effects were mimicked by 10 nM phorbol-12-myristate-13-acetate, a PKC activator, but attenuated by 5 microM chelerythrine, a PKC inhibitor. More importantly, 0.1 microM epsilonV1-2, a selective PKC-epsilon inhibitor administered before and during MIP/UP, also attenuated the effects of both treatments on cell injury/death and translocation of PKC-epsilon. On the other hand, 5 microM rottlerin, a selective PKC-delta inhibitor, did not alter the effects of either treatment on injury/death. The results indicate that both MIP and UP activate PKC-epsilon, leading to delayed cardioprotection in rat ventricular myocytes.