Chronic continuous light exposure leads to melatonin deficiency along with complex neurohumoral activation resulting in hypertension development in rats. The aim of this study was to show, whether continuous light in duces fibrotic rebuilding of the aorta and whether the treatment with melatonin or angiotensin converting enzyme inhibitor captopril can prevent these potential alterations. In a six-week experiment, 3-month-old Wistar rats were divided into 4 groups (t en per group): controls, rats exposed to continuous light, exposed to continuous light plus treated with captopril (100 mg/kg/24 h) and exposed to continuous light plus treated with melatonin (10 mg/kg/24 h). Systolic blood pressure (SBP) and collagen type I and III in the media of thoracic aorta were me asured. Continuous light induced hypertension and fibrotic rebuilding of the aorta in terms of enhancement of collagen I and III concentration in the aortic media. Both captopril and melatonin prevented SBP rise and reduced collagen III concentration in the aorta. However, only melatonin reduced collagen I and the sum of collagen I and III in the aortic tissue. We conclude that in continuous light-induced hypertension, administration of melatonin, along with SBP reduction, decreases collagen I and III concentration in the aorta. It is suggested that antifibrotic effect of melatonin may reduce the stiffness of the aorta and small arteries and beneficially influence the nature of the pulse wave and peripheral vascular resistance., K. Repová-Bednárová ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Troponin T (TnT) is recently being considered to be an important diagnostic marker of myocardial damage in adults, but this marker has not yet been used in neonates. The present study was designed to determine the normal level of cardiac TnT in the cord blood of healthy term neonates. Cardiac troponin T concentration in cord blood was measured in 15 healthy term neonates using commercial kit (Enzymun-Test System, Boehringer, Mannheim). TnT serum concentration was 0.05±0.04 /ig/1 in 10 of 15 babies whereas in the remaining 5 haemolysed samples its concentration was elevated (mean 0.19±0.07 /vg/1). It is important to consider that incidental haemolysis of blood samples can mimic pathological elevation of TnT by interfering with the assay.