ABSTRACT
Abstract Purpose: To evaluate whether combining hypothermia and remote ischemic preconditioning (RIPC) results in protection from ischemia-reperfusion (IR). Methods: Thirty-two Wistar rats underwent right nephrectomy and were randomly assigned to four experimental protocols on the left kidney: warm ischemia (group 1), cold ischemia (group 2), RIPC followed by warm ischemia (group 3), and RIPC followed by cold ischemia (group 4). After 240 minutes of reperfusion, histological changes in the left kidney, as well as lipid peroxidation and antioxidant enzyme activity, were analyzed. The right kidney was used as the control. Serum creatinine was collected before and after the procedures. Results: RIPC combined with hypothermia during IR experiments revealed no differences on interventional groups regarding histological changes (p=0.722). Oxidative stress showed no significant variations among the groups. Lower serum creatinine at the end of the procedure was seen in animals exposed to hypothermia (p<0.001). Conclusions: Combination of RIPC and local hypothermia provides no renal protection in IR injury. Hypothermia preserves renal function during ischemic events. Furthermore, RIPC followed by warm IR did not show benefits compared to warm IR alone or controls in our experimental protocol.
Subject(s)
Animals , Male , Rats , Reperfusion Injury/prevention & control , Oxidative Stress/physiology , Ischemic Preconditioning/methods , Hypothermia, Induced/methods , Kidney/blood supply , Superoxide Dismutase/metabolism , Rats, Wistar , Combined Modality Therapy , Disease Models, Animal , Cold Ischemia , Warm Ischemia , Kidney/pathologyABSTRACT
Abstract Purpose: To evaluate whether their combination was more effective than either alone in decreasing renal damage due to ischemia/reperfusion (I/R) injury in rats. Methods: Thirty-two Wistar rats were assigned to four groups. Following right nephrectomy, their left kidneys were subjected to warm ischemia (IR), cold ischemia (TH+IR), intraperitoneal injection of 10 mg/kg melatonin (MEL+IR), or injection of 10 mg/kg melatonin followed by cold ischemia (MEL+TH+IR). Eight randomly assigned right kidneys constituted the control group. After 240 min of reperfusion, left nephrectomy was performed for histopathological evaluation, lipid peroxidation, and measurement of antioxidant enzyme activity. Serum was collected to measure urea and creatinine concentrations. Results: Histopathological damage induced by ischemia and reperfusion was more attenuated in the MEL+TH+IR group than in the MEL+IR and TH+IR groups (p<0.037). Superoxide dismutase activity was significantly higher (p<0.029) and creatinine (p<0.001) and urea (p<0.001) concentrations were significantly lower in the MEL+TH+IR group than in the MEL+IR and TH+IR groups. Conclusion: The combination of melatonin (MEL) and topical hypothermia (TH) better protects against renal I/R injury than does MEL or TH alone.
Subject(s)
Animals , Male , Rats , Reperfusion Injury/prevention & control , Hypothermia, Induced/methods , Kidney/blood supply , Melatonin/therapeutic use , Superoxide Dismutase/metabolism , Reperfusion Injury/pathology , Rats, Wistar , Combined Modality Therapy , Oxidative Stress , Disease Models, Animal , Malondialdehyde/metabolismABSTRACT
No Sistema Único de Saúde do Brasil (SUS), os níveis de atenção à saúde se inserem no modelo hierárquico através do sistema de referência e contrarreferência. Em um projeto para atender às demandas represadas do nível primário ao secundário, denominado "Mutirão da Saúde", realizado em Porto Alegre, os médicos neurologistas do Hospital de Clínicas de Porto Alegre, após cada atendimento realizado, responderam a um instrumento para avaliar os encaminhamentos realizados pela rede de atenção primária à saúde (APS). A avaliação foi positiva, mostrando que os encaminhamentos foram realmente necessários em 85 por cento dos casos; entretanto, foi parcialmente contraditória, tendo em vista que 41,7 por cento dos encaminhamentos eram situações clínicas que deveriam ser manejadas no atendimento primário. A avaliação também revelou que 50 por cento dos casos necessitavam de exames complementares. Devido a uma possível regionalização aleatória dos encaminhamentos, o resultado não nos possibilitou uma estimativa apropriada da prevalência por territórios das unidades de APS, informação esta importante para a organização do fluxo de encaminhamentos e planejamento dos recursos alocados pelos gestores, tanto locais quanto municipais.
In the Unified Health System in Brazil (SUS), the levels of health care fall within the hierarchical model with the reference and counter-reference systems. In a project to meet the repressed demands of primary and secondary levels, called "Mutirão da Saúde", held in Porto Alegre, the neurologists of the Hospital de Clinicas de Porto Alegre, after each call made, answered a questionnaire to assess referrals performed by the network of primary health care (PHC). The evaluation was positive, showing that the referrals were really needed in 85 percent of cases; however, it was partially contradictory, given that 41.7 percent of referrals were medical conditions that should be managed in primary care. The evaluation also revealed that 50 percent of cases needed further investigation. Due to a possible randomized regionalization of referrals, the result did not allow us to estimate the appropriate prevalence according to areas of the PHC units, information that is important to organize the flow of referrals and planning of resources allocated by managers, both local and municipal.