RESUMEN
Concepts from disciplines such as Biochemistry, Genetics, Cellular and Molecular Biology are essential to the understanding and treatment of an elevated number of illnesses, but often they are studied separately, with no integration between them. This article proposes a model for basic sciences integration based on problem-based learning (PBL) and compares failure rate, global final grade, approved student final grade, grade distribution and students' satisfaction with teacher conduction between integrated curriculum and traditional learning in health courses from Anhembi Morumbi University-a private institution from Brazil. Comparison between integrated and traditional curriculum was based on students' records obtained from first-year health sciences students. A total of 1,697 records from 2005 to 2007 (nonintegrated curriculum) and 785 records from 2008 (integrated curriculum) were selected for this study and they were necessary to get information about students' grades. Moreover, a questionnaire was applied in order to cover student's satisfaction with teacher conduction. The data presented in this study indicated that the integrated curriculum based on PBL was related to an improvement in student's grades and satisfaction compared with traditional teaching. We believe that the effectiveness in health education will be a combination of "classical" presentation of contents associated to actively involved students in the educational process and methodology based on problems in order to create the stimulus for the undergraduates continue to integrate basic and clinical investigation.
Asunto(s)
Disciplinas de las Ciencias Biológicas/educación , Educación de Pregrado en Medicina/métodos , Aprendizaje Basado en Problemas/métodos , Adolescente , Brasil , Curriculum , Educación de Pregrado en Medicina/estadística & datos numéricos , Evaluación Educacional/estadística & datos numéricos , Humanos , Modelos Educacionales , Satisfacción Personal , Aprendizaje Basado en Problemas/estadística & datos numéricos , Estudiantes/psicología , Encuestas y Cuestionarios , Adulto JovenRESUMEN
The objective of this study was to evaluate the effect of ischemic preconditioning upon lesions produced by ischemia-reperfusion of the small intestine. Thirty EPM-1 Wistar rats were randomly distributed into three groups: ischemic preconditioning (IPC; n = 12), ischemia-reperfusion (I/R; n = 12), and control (C; n = 6). Laparotomy permitted isolation of the mesenteric artery for clamping. The animals were heparinized and hydrated. IPC was induced by: 10 minutes of ischemia followed by 10 minutes of reperfusion and then 50 minutes ischemia followed by another 30 minutes reperfusion. Group I/R was submitted to the same protocol except for the 20 minutes of preconditioning. Group C animals underwent only laparotomy for 100 minutes. After reperfusion small intestine fragments were examined histologically. Blood samples were obtained to measure LDH and lactate prior to euthanasia. Lactate values were significantly lower in the IPC as compared to I/R group, 39 versus 67 mg/dL, respectively (P < or =.05). However, neither IPC (grade 3) lesions of the mucosa versus I/R (grade 4) nor LDH values (PCI = 680, I/R = 873 U/L) were statistically different. Thus No morphological evidence of protection was observed following ischemic preconditioning.
Asunto(s)
Intestino Delgado/patología , Precondicionamiento Isquémico , Daño por Reperfusión/prevención & control , Animales , Modelos Animales de Enfermedad , Intestino Delgado/irrigación sanguínea , Masculino , Ratas , Ratas Wistar , Valores de Referencia , Daño por Reperfusión/patologíaRESUMEN
To assess the effect of chronic ethanol ingestion in the content of the reduced forms of coenzymes Q9 (ubiquinol-9) and Q10 (ubiquinol-10) as a factor contributing to oxidative stress in liver and brain, male Wistar rats were fed ad libitum a basal diet containing either 10 or 2.5 mg alpha-tocopherol/100 g diet (controls), or the same basal diet plus a 32% ethanol-25% sucrose solution. After three months treatment, ethanol chronically-treated rats showed identical growth rates to the isocalorically pair-fed controls, irrespectively of alpha-tocopherol dietary level. Lowering dietary alpha-tocopherol led to a decreased content of this vitamin in the liver and brain of control rats, without changes in that of ubiquinol-9, and increased levels of hepatic ubiquinol-10 and total glutathione (tGSH), accompanied by a decrease in brain tGSH. At the two levels of dietary alpha-tocopherol, ethanol treatment significantly decreased the content of hepatic alpha-tocopherol and ubiquinols 9 and 10. This effect was significantly greater at 10 mg alpha-tocopherol/100 g diet than at 2.5, whereas those of tGSH were significantly elevated by 43% and 9%, respectively. Chronic ethanol intake did not alter the content of brain alpha-tocopherol and tGSH, whereas those of ubiquinol-9 were significantly lowered by 20% and 14% in rats subjected to 10 and 2.5 mg alpha-tocopherol/100 g diet, respectively. It is concluded that chronic ethanol intake at two levels of dietary alpha-tocopherol induces a depletion of hepatic alpha-tocopherol and ubiquinols 9 and 10, thus contributing to ethanol-induced oxidative stress in the liver tissue. This effect of ethanol is dependent upon the dietary level of alpha-tocopherol, involves a compensatory enhancement in hepatic tGSH availability, and is not observed in the brain tissue, probably due to its limited capacity for ethanol biotransformation and glutathione synthesis.
Asunto(s)
Encéfalo/efectos de los fármacos , Etanol/administración & dosificación , Hígado/efectos de los fármacos , Ubiquinona/análogos & derivados , Ubiquinona/metabolismo , Vitamina E/administración & dosificación , Animales , Encéfalo/metabolismo , Dieta , Glutatión/metabolismo , Hígado/metabolismo , Masculino , Oxidación-Reducción , Estrés Oxidativo , Ratas , Ratas WistarRESUMEN
The influence of acute ethanol administration on the oxidative stress status of rat brain and liver was assessed by in situ spontaneous organ chemiluminescence (CL). Brain and liver CL was significantly increased after acute ethanol administration to fed rats, a response that is time-dependent and evidenced at doses higher than 1 g/kg. Ethanol-induced CL development is faster in liver compared with brain probably due to the greater ethanol metabolic capacity of the liver, whereas the net enhancement in brain light emission at 3 h after ethanol treatment is higher than that of the liver, which could reflect the greater susceptibility of brain to oxidative stress. The effect of ethanol on brain and liver CL seems to be mediated by acetaldehyde, due to its abolishment by the alcohol dehydrogenase inhibitor 4-methylpyrazole and exacerbation by the aldehyde dehydrogenase inhibitor disulfiram. In brain, these findings were observed in the absence of changes in the activity of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glucose-6-phosphate dehydrogenase. However, the content of brain glutathione was significantly decreased by 31%, by ethanol, thus establishing an enhanced oxidative stress in this tissue.
Asunto(s)
Encéfalo/metabolismo , Etanol/toxicidad , Peroxidación de Lípido/efectos de los fármacos , Hígado/metabolismo , Estrés Oxidativo/efectos de los fármacos , Disuasivos de Alcohol/farmacología , Animales , Antioxidantes/metabolismo , Encéfalo/efectos de los fármacos , Disulfiram/farmacología , Relación Dosis-Respuesta a Droga , Fomepizol , Glutatión/metabolismo , Inyecciones Intraperitoneales , Hígado/efectos de los fármacos , Mediciones Luminiscentes , Masculino , Pirazoles/farmacología , Ratas , Ratas Wistar , Factores de TiempoRESUMEN
While acute lindane treatment and chronic ethanol feeding to rats have been associated with hepatic oxidative stress, the possible roles of these stresses in the pathogenesis of hepatic lesions reported in acute lindane intoxication and in those observed in some models of chronic alcoholism have not been established. Our previous studies in rats chronically fed ethanol regimens and then treated with a single intraperitoneal (i.p.) dose of lindane (20 mg/kg) showed that while lindane per se was invariably associated with hepatic oxidative stress, chronic ethanol feeding only produced this stress when the dietary level of vitamin E was relatively low. Chronic ethanol pretreatment did not significantly affect the lindane-associated oxidative stress, and neither chronic ethanol feeding nor acute lindane, single or in combination, produced any histologic and biochemical evidence of liver damage. In the present experiment, the acute dose of lindane was increased to 40 mg/kg, and we have studied a larger number of prooxidant and antioxidant hepatic factors. Male Wistar rats (115.5 +/- 5.4 g) were fed ad lib for 11 weeks a calorically well-balanced and nutritionally adequate basal diet, or the same basal diet plus a 32% ethanol/25% sucrose solution, also ad lib, and were then injected i.p. with a single dose of lindane or with equivalent amounts of corn oil. The results indicated that acute lindane treatment to naive rats increased practically all the prooxidant hepatic factors examined (cytochromes P450 and b5, NADPH cytochrome c reductase, NADPH oxidase), as well as the generation of microsomal superoxide radical and thiobarbituric acid reactive substances of liver homogenates, but did not modify any of the antioxidant hepatic factors studied. Conversely, the chronic administration of ethanol alone did not significantly affect the prooxidant hepatic factors but reduced some of the antioxidants (i.e., the activities of GSH-Px and the contents of alpha-tocopherol and ubiquinols 9 and 10). Although chronic ethanol pretreatment further increased the superoxide generation induced by lindane per se, it did not increase but generally reduced the effects of lindane per se on the other prooxidant factors studied. Furthermore, although acute lindane administration to ethanol-pretreated rats was associated with decreases in GSH and catalase (not affected by ethanol or lindane treatment alone), it did not substantially modify the reducing effects of ethanol feeding per se on GSH-Px, alpha-tocopherol, and ubiquinols. Once again, neither chronic ethanol feeding nor lindane treatment, single or in combination, was associated with any evidence of liver damage.