RESUMEN
OBJECTIVE: To assess the hypothesis that changes in plasma total bilirubin levels (Btot) can influence the antioxidant system and oxidative stress in preterm infants. METHODS: Twenty two healthy preterm infants who presented with visible non-haemolytic hyperbilirubinaemia were studied at the mean (SD) age of 3.7 (1.5) days. Btot, plasma total hydroperoxide concentration (TH), plasma protein SH group concentration, and total antioxidant capacity of the plasma (TAC) were measured at study entry and after 24 hours. RESULTS: Btot did not correlate with TH, TAC, or protein SH group concentration, but a significant correlation was found between TH and TAC, TH and protein SH groups, and TAC and protein SH groups, both at study entry and after 24 hours. CONCLUSION: The decrease in plasma bilirubin was contemporary with an increase in plasma antioxidant capacity and decrease in oxidative stress in preterm infants. This may be the result of the pro-oxidant effect of haem oxygenase, mediated by iron release, which may outcompete the antioxidant properties of bilirubin.
Asunto(s)
Bilirrubina/sangre , Hiperbilirrubinemia/sangre , Enfermedades del Prematuro/sangre , Estrés Oxidativo , Antioxidantes/metabolismo , Femenino , Humanos , Peróxido de Hidrógeno/sangre , Recién Nacido , Recien Nacido Prematuro , MasculinoRESUMEN
PURPOSE: To evaluate reactive oxygen species and antioxidant status in essential arterial hypertension during therapy with dihydropiridine calcium channel antagonists. PATIENTS AND METHODS: Fifteen patients, affected by essential arterial hypertension, were examined. They received once a day oral dihydropyridine calcium antagonists for 10 weeks: five patients received felodipine (5 mg), five amlodipine (10 mg) and five lercanidipine (10 mg). The levels of end products of lipid peroxidation, free radicals and hydroperoxides and total antioxidant capacity were determined in the plasma of all subjects before and during treatment. Values are expressed as mean +/- S.E. Systolic blood pressure decreased from 171 +/- 4 to 135 +/- 6 mmHg (p < 0.01) and diastolic blood pressure decreased from 99 +/- 5 to 82 +/- 3 mmHg (p < 0.01). Hydroperoxides and free radicals decreased from 321.3 +/- 8.96 to 247.9 +/- 8.69 units (p < 0.01) and the end products of lipid peroxidation decreased from 11.0 +/- 1.93 to 6.74 +/- 1.41 nmol/ml (p < 0.01). Total antioxidant capacity increased from 0.74 +/- 0.03 to 1.05 +/- 0.05 mmol/l (p < 0.01). RESULTS: Imbalance in the pro-oxidant-antioxidant equilibrium shifts in favour of antioxydant namely oxidative stress decreases. The calcium channel antagonists decrease peripheral arterial resistances and therefore decrease or abolish relative ischaemia, moreover decrease arterial pressure and therefore normalize parietal stress on endothelial cells. As a conseguence they act on two hypothesized mechanisms of oxidative stress in hypertension. CONCLUSIONS: Dihydropyridine calcium antagonists used in this trial seem useful in hypertension because they decrease oxidative stress, and normalize of pressure values.
Asunto(s)
Bloqueadores de los Canales de Calcio/uso terapéutico , Dihidropiridinas/uso terapéutico , Hipertensión/tratamiento farmacológico , Especies Reactivas de Oxígeno/metabolismo , Adulto , Anciano , Antioxidantes/metabolismo , Femenino , Humanos , Hipertensión/sangre , Peroxidación de Lípido , Masculino , Persona de Mediana EdadRESUMEN
Patients with chronic renal failure, and particularly those receiving regular haemodialysis, have a high incidence of premature cardiovascular disease. Oxidative stress, which causes lipid peroxidation, may contribute to increase the risk of atherosclerosis. The results of the present study indicate that lipid peroxidation products (malonaldehyde and 4-hydroxyalkenals) are significantly increased in plasma of renal patients before dialysis and, although reduced, remained above the normal range after this treatment. Moreover, production of free radicals and reactive oxygen metabolites was increased in chronic renal failure patients, especially after dialysis. On the other hand, the antioxidant defenses of those patients were higher than those of normal subjects, as judged from the plasma levels of specific antioxidant molecules and from the plasma antioxidant capacity. We also found that triglycerides were significantly higher in renal patients, both before and after dialysis, than in the control group. These results suggest that patients on chronic haemodialysis are particularly prone to oxidative stress and that dialysis itself may worsen this condition. Rather than to a weakening of antioxidant defenses, the susceptibility of chronic renal failure patients to oxidative stress might be ascribed to an increased free radical and reactive oxygen metabolite production and to increased levels of oxidizable substrates, notably triglycerides with their unsaturated fatty acids.
Asunto(s)
Fallo Renal Crónico/terapia , Estrés Oxidativo , Diálisis Renal/efectos adversos , Antioxidantes/análisis , Arteriosclerosis/etiología , Cromanos/análisis , Ácidos Grasos Insaturados/sangre , Femenino , Humanos , Fallo Renal Crónico/sangre , Peroxidación de Lípido , Masculino , Malondialdehído/sangre , Persona de Mediana Edad , Especies Reactivas de Oxígeno/metabolismo , Factores de Riesgo , Triglicéridos/sangreRESUMEN
21-Aminosteroids (Lazaroids), acting as free radical scavengers and as membrane stabilizers, proved to have beneficial effects in various pathological conditions. In the present study we explored the effectiveness of one of these compounds, U 74389 G, in protecting pigs myocardium against the ischemia-reperfusion damage induced by transient coronary occlusion achieved by clampling the left anterior descending coronary artery. Animals were divided into three groups: control, untreated and treated. Control animals were operated but not subjected to ischemia-reperfusion; the untreated group underwent to ischemia-reperfusion without pharmacological treatment; while the treated group received the aminosteroid (4 mg/kg) before coronary occlusion and at the time of reperfusion. Specimens of myocardial tissue and blood samples were taken for morphological and biochemical studies. In the ischemic-reperfused myocardium of the untreated animals, the dominant morphological features were neutrophil infiltration, intercellular edema and severe swelling of mitochondria. All these alterations, notably neutrophil infiltration, were attenuated by aminosteroid treatment. As for the biochemical findings, the changes in adenine nucleotides and nucleosides levels, thus the reduction of energy charge, were reversed in the treated, but not in the untreated group. Myocardial concentration of malondialdehyde, which was undetectable in the control group, was raised in all the animals after reperfusion, but this effect was significantly less marked with aminosteroid treatment. In addition, the higher myocardial content of ascorbic acid and the reduced serum potential peroxidation exhibited by the treated animals compared with untreated group indicate an enhanced antioxidant protection induced by aminosteroid administration. On the other hand, the serum levels of myoglobin, cardiac troponin I and creatine kinase MB isoenzyme suggest the ability of the aminosteroid to attenuate the modifications of membrane permeability induced by ischemia-reperfusion injury. All these results lead to the conclusion that aminosteroid treatment, at least in the conditions of the present study, is effective in reducing the morphological and biochemical alterations occurring in ischemic-reperfused myocardium.
Asunto(s)
Antioxidantes/farmacología , Daño por Reperfusión Miocárdica/prevención & control , Pregnatrienos/farmacología , Adenosina Difosfato/metabolismo , Adenosina Monofosfato/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Femenino , Hemodinámica , Masculino , Isquemia Miocárdica/metabolismo , Daño por Reperfusión Miocárdica/metabolismo , PorcinosRESUMEN
Recently, endotoxaemia has been reported as a prognostic marker in acute pancreatitis. However, the role of endotoxin in inducing or aggravating acute pancreatitis is not fully understood. We administered endotoxin 400 micrograms/kg i.p. to rats 24 h before performing either a closed duodenal loop (group B) or a sham operation (group D). Pancreatic damage and overall survival were compared with the results obtained in rats not exposed to endotoxin undergoing either closed duodenal loop (group A) or sham treatment (group C). In a first set of experiments, 24 h after laparotomy blood samples were collected and the animals were sacrificed; survival up to 8 days was estimated in a second set of experiments. Group B had higher lipase concentrations and more severe tissue damage than group C (P < 0.05). A larger number of abscesses was observed in both group B and group D as compared to group C (P < 0.05). Survival was significantly shorter in group B (P < 0.0001). We conclude that priming with endotoxin worsens the extent of pancreatic damage induced by the closed duodenal loop procedure in the rat, possibly favouring selective homing of neutrophils to the site of inflammation, in similarity to what happens in the Shwartzman phenomenon.