The MMP-9/TIMP-1 ratio increased during HD sessions, although their absolute levels were lowered. This change may represent a chronic state of enhanced fibrosis in patients undergoing HD.

Lipid peroxidation, as a well-known index of reactive oxygen species activity, not only in lung biochemistry, is an oxidative process associated with membrane lipid destruction. Also, the oxidative modification of nucleic acids by reactive oxygen species is of remarkable biological importance as it may contribute to malignant conversion, but its exact role in lung cancer biology is still not clear. Our study aimed to investigate the level of lipid peroxidation ex vivo in tumour tissue and lung parenchyma obtained from patients with lung cancer. Forty-two patients with lung cancer were enrolled into the study. During a surgical resection, tumour tissue and lung parenchyma were obtained and concentration of lipid peroxidation products, thiobarbituric acid-reactive substances and Schiff bases, and spontaneous generation of hydrogen peroxide, were measured. The concentration of thiobarbituric acid-reactive substances (P<0.001) in the tumour tissue was higher than that in lung parenchyma. In small cell lung cancer as well as in squamous cell carcinoma patients, a positive correlation between spontaneous generation of hydrogen peroxide in tumour tissue and clinical stage (r = 0.43; r = 0.46; respectively) was found. Our results prove enhanced lipid peroxidation in cancer tissue as compared with matched-lung parenchyma. In small cell lung cancer and squamous cell carcinoma patients, the high level of oxidative stress, expressed as a spontaneous generation of hydrogen peroxide in tumour tissue, was associated with clinical progression of tumour's stage.

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The purpose of this study was to elucidate the participation of plasma PON1 (paraoxonase activity [PON] and arylesterase activity [ARE]) in antioxidant defense in response to a single bout of maximal exercise. PON, ARE, lipid profile, lipid peroxidation (thiobarbituric acid reactive substances [TBARS]), total antioxidant status (ferric reducing ability of plasma [FRAP]), concentration of uric acid [UA], and total bilirubin (TBil) were determined in the plasma before, at the bout and 2 h after maximal exercise on a treadmill in young sportsmen. Chosen physiological parameters also were controlled during maximal exercise. Following maximal exercise, the unaltered level of TBARS and increased FRAP were registered. ARE increment was the highest (37.6%) of all measured variables but lasted for a short time. UA increment was lower than ARE but long-lasting and correlated with FRAP. PON activity increment was associated with the combined effect of body weight, lean, body mass index (BMI) and basal metabolic rate (BMR). We conclude that PON1 is a co-factor of the first line of antioxidant defense during maximal exercise. Its activity is associated with body composition and not the physical fitness of the subjects.

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