Effect of exercise on plasma paraoxonase1 activity in rugby players: dependance on training experience.

OBJECTIVES: There are conflicting data on the influence of physical activity on paraoxonase1 (PON1) activity. The purpose of this study is to investigate the effect of maximal exercise (ME) on plasma paraoxonase (PON) and arylesterase (ARE) activity in elite rugby players. In addition, the influence of training experience and PON1 Q192R polymorphism on PON1 activity changes at ME was evaluated. METHODS: Twenty-five elite rugby players ages 22.0±3.71 years, consisting of 11 juniors--J (2-7 years of training) and 14 seniors--S (8-15 years of training), completed ME on a cycle ergometer. PON and ARE activity, ferric reducing activity of plasma (FRAP), uric acid (UA), and total bilirubin concentration, as well as thiobarbituric acid reactive substances and lipid profile were investigated in the plasma before, at the bout, and 30 minutes after ME. RESULTS: At the bout of ME we found an increase in PON1 activities, ARE/high-density lipoprotein C ratio, TBil, and TChol. However, ARE activity changes were not observed in the group of rugby players training for ≤7 years. FRAP and UA increased later--30 minutes after ME. CONCLUSION: We conclude that in rugby players PON1 changes during ME depend on age, body composition, and training experience. The influence of PON1 Q192R polymorphism on PON1 changes at ME remains debatable.

Effect of single bout of maximal exercise on plasma antioxidant status and paraoxonase activity in young sportsmen.

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.

Decreased H2O2 in exhaled breath condensate during pregnancy--feasible effect of 17beta-estradiol.

Since pregnancy is known to favor systemic generation of reactive oxygen species, this study was designed to assess the levels of exhaled hydrogen peroxide (eH2O2), serum progesterone (PG), 17beta-estradiol (E2) and systemic oxidative parameters in 20 pregnant women between 15th and 28th gestation week and 23 healthy, eumenorrheic women. Exhaled breath condensate H2O2 was assessed fluorometrically with homovanillic acid. Exhaled H2O2 levels were lowered in pregnancy (median Me 0.13 microM) compared with follicular (Me 0.29 microM) or luteal phase (Me 0.26 microM; p<0.05 vs. both). The follicular H2O2 tended to exceed luteal phase. Whole blood chemiluminescence was increased approximately ten fold in pregnancy. E2 markedly decreased chemiluminescence of isolated polymorphonuclear leukocytes. In vitro ferric reducing ability of plasma and 2,2-diphenyl-1-picryl-hydrazyl scavenging assay were not affected by E2 or PG. Decreased exhaled H2O2 during pregnancy, despite of the increased oxidative capacity of peripheral phagocytes, might be ascribed to the magnitude of increased 17beta-estradiol levels.

Elevated exhalation of hydrogen peroxide and circulating IL-18 in patients with pulmonary tuberculosis.

Mycobacteria are the strong stimulators of respiratory burst, resulting in production of reactive oxygen species and nitrogen intermediates. The aim of our study was to assess the concentration of hydrogen peroxide (H(2)O(2)) in expired breath condensate (EBC) and the serum level of interleukin-18 (IL-18) in patients with active pulmonary tuberculosis (TB) before introduction of chemotherapy and after 2 months of treatment. Sixteen patients, current cigarette smokers, with advanced pulmonary TB were enrolled into the study. As a control served two groups: I group--16 asymptomatic cigarette smokers, II group--17 healthy never smoked subjects. The level of H(2)O(2) in EBC was significantly higher in patients with TB (1.3+/-0.7 microM) as compared to cigarette are healthy nonsmoker subjects (0.4+/-0.1 and 0.2+/-0.1 microM, respectively, P<0.05). Two months of treatment significantly decreased the level of H(2)O(2) exhalation in TB patients (0.5+/-0.3 microM) to the value that was not different from that in asymptomatic smokers but was still higher than in never smoked subjects. Serum concentration of IL-18 in TB patients was higher than that found in both control groups either before and after antituberculous treatment (P<0.05). Exhaled H(2)O(2) did not correlate with circulating IL-18 in TB patients before or after treatment. These results demonstrated the occurrence of oxidative stress in the airways of TB patients completely attenuating after 2 months of successful antituberculous treatment.

Elevated whole blood chemiluminescence in patients with systemic sclerosis.

OBJECTIVE: Systemic sclerosis (SSc) is accompanied by oxidative stress that in turn may accelerate endothelium degeneration and thus disease progression. We tested whether phagocytes from SSc patients release more reactive oxygen species (ROS) and whether this release correlates with some clinical parameters. METHODS: ROS production by blood phagocytes was measured with the luminol enhanced whole blood chemiluminescence (CL). Resting and N-formyl-methionyl-leucyl-phenylalanine -induced CL (fMLP-induced CL) was measured in 30 patients with SSc and 30 healthy controls matched as to age, sex, and level of cigarette smoking. RESULTS: Resting CL and fMLP-induced CL calculated per 10(4) phagocytes present in the assayed blood sample were higher in patients with systemic sclerosis than in healthy controls (median; range, 0.88; 0.47-1.39 vs. 0.73; 0.13-1.07 aU/10(4)p and 621; 293-3522 vs. 411; 289-810 aUxs/10(4)p, p<0.02). Patients treated with cyclophosphamide and/or prednisone for 11; 3-168 months did not differ in respect to CL from those that never received the medications. Similarly, no significant differences were found between patients with limited and diffuse SSc. Resting CL correlated (p<0.05) with clinically manifested interstitial lung disease (r=0.59), single breath carbon monoxide diffusing capacity (r= -0.56) and serum autoantibodies titre (r= 0.43). CONCLUSIONS: Blood phagocytes from patients with systemic sclerosis, especially from those with interstitial lung disease, generate elevated amounts of ROS as assessed with CL. This confirms the presence of systemic oxidative stress in SSc patients.

Exhaled hydrogen peroxide correlates with the release of reactive oxygen species by blood phagocytes in healthy subjects.

Various cells including polymorphonuclear leukocytes, alveolar macrophages and type-II pneumocytes may be a source of exhaled hydrogen peroxide (H2O2) in airways of humans. H2O2 can convert into hydroxyl radicals leading to peroxidative damage of airways structures and formation of volatile thiobarbituric acid-reactive substances (TBARs). We tested whether exhalation of H2O2 and TBARs by healthy subjects depends on reactive oxygen species generation from blood phagocytes. The expired breath condensate (EBC) and blood specimens were collected from 41 healthy, never smoked subjects (mean age 20.7 +/- 0.8 years, 18 men, 23 women) and then the EBC concentration of H2O2 and TBARs and 2 x 10(-5) M fMLP-provoked whole blood chemiluminescence response was measured. The mean concentration of H2O2 and TBARs in EBC was 0.28 +/- 0.17 and 0.04 +/- 0.13 microM with ratio of positive readings reaching 36/41 and 4/41, respectively. The chemiluminescence response to n-formyl-methionyl-leveyl-phenylalanine stimulation was obtained in all cases and the following parameters were estimated: basal chemiluminescence (bCl); peak chemiluminescence (pCl); absolute light emission (aCl); and peaktime. H2O2 levels in EBC positively correlated (Spearmann test) with bCl (r=0.41, P<0.01), pCl (r=0.47, P<0.01), aCl (r=0.49, P<0.001), peaktime (r=0.52, P<0.001) in the whole group and with bCl (r=0.56, P<0.01), pCl (r=0.67, P<0.01), aCl (r=0.66, P<0.01) in men and with aCl (r=0.41, P<0.05) and peaktime (r=0.48, P<0.05) in women. No association between exhaled TBARs and blood phagocytes activity was found. These results indicate that H2O2 exhalation in healthy never smoked subjects depends on ability of blood phagocytes to generate reactive oxygen species.

Elevated exhalation of hydrogen peroxide in patients with systemic sclerosis.

BACKGROUND: Systemic sclerosis is accompanied by an influx of activated phagocytes into distal airways. These cells release H2O2, which may evaporate from the airways surface and be detected in expired breath condensate. We tested whether patients with systemic sclerosis exhale more H2O2 than healthy subjects and whether breath condensate H2O2 levels correlate with some clinical parameters. MATERIAL AND METHODS: H2O2 was measured fluorimetrically in the expired breath condensate of 27 patients (22 women, five men, mean age 49 +/- 13.1 years) with systemic sclerosis and 27 age- and sex- matched healthy controls. RESULTS: Exhaled H2O2 levels were 3.5-fold higher (0.88 +/- 0.62 microM vs. 0.25 +/- 0.17 microM, P < 0.001) in the patients with systemic sclerosis than in the controls. Treatment with cyclophosphamide and/or prednisone (29 +/- 50 months, range 3-168 months) did not significantly decrease H2O2 exhalation (0.78 +/- 0.50 microM, n= 10 vs. 0.94 +/- 0.67 microM, n= 17, P > 0.05). No significant difference was found between patients with limited and diffuse scleroderma (1.03 +/- 0.69 microM, n= 17 vs. 0.63 +/- 0.41 microM, n= 10, P > 0.05). H2O2 levels correlated with disease duration (r = 0.38, P < 0.05) and time from the first Raynaud's episode (r = 0.44, P < 0.05). CONCLUSIONS: Patients with systemic sclerosis exhale more H2O2 than healthy controls, suggesting involvement of reactive oxygen species in disease processes. Lack of significant intergroups differences in H2O2 levels may have resulted from the small number of patients analyzed.

Increase of gonadotropin-releasing hormone concentration in pituitary portal blood after substance P administration in male rats.

Substance P (SP) affects gonadotropin release from the anterior pituitary gland. In the present study we tested whether SP exerts this effect through GnRH release into pituitary portal blood in intact male rats (INT), orchidectomized rats with s.c. chronically implanted empty Silastic capsule (ORCX), testosterone capsule (ORCX + T), and 17beta-estradiol capsule (ORCX + E2). The pituitary glands were exposed by the transpharyngeal approach under urethane-chloralose anesthesia. Then, the stalk portal vessels were cut and three 30-min portal blood samples were collected. Each first sample of blood was treated as a control before 0.2 ml injection of normal saline, 5 microg, or 25 microg of SP in 0.2 ml of normal saline into the internal carotid artery. GnRH concentration in the purified portal plasma were measured by RIA. Injection of SP into the internal carotid artery caused a significant increase in GnRH concentration in pituitary portal plasma only in INT rats. The higher dose of SP markedly increased GnRH concentration in the 1st blood sample (p < 0.001) and in the 2nd blood sample GnRH concentration was lower but still significant higher than prior SP injection (p < 0.05). The lower dose of SP increased GnRH concentration later, only in the 2nd portal blood sample after intracarotid SP injection (p < 0.001). Injection of normal saline had no effect on GnRH concentration in pituitary portal blood in INT rats. In ORCX, ORCX testosterone- and estrogen-implanted rats portal plasma GnRH concentrations were not changed significantly after injection of both doses of SP. These results indicate that SP stimulates GnRH release into pituitary portal blood and the influence of SP on GnRH neurons depends on the levels of circulating gonadal steroid hormones.

Hypophysial portal blood flow during preganglionic stimulation of the superior cervical ganglion under condition of systemic arterial blood pressure stabilization in rat.

The presence of hypothalamic hormones in the pituitary portal blood is regarded as the principal factor by which the hypothalamus controls pituitary secretion. In contrast to numerous investigations on hypothalamic hormone release, the regulation of the hypophysial-portal blood flow (HPBF) has been scarcely studied. Hypophysial-portal vessels were exposed according to the Worthington's method [1966]. The 10-min blood samples were collected before and during unilateral or alternative bilateral electrical stimulation of the preganglionic fibers of the superior cervical ganglia (SCG). During blood samples collection the stable systemic arterial blood pressure was maintained by a barostat. The HPBF was estimated according to the determination of the hemoglobin in samples of washed and collected blood from the cut pituitary portal vessels. The mean HPBF was 3.5 microliters/min. Electrical stimulation of SCG. did not change HPBF. This indicates that sympathetic efferents do not participate in the regulation of HPBF under conditions of stabilization of the systemic arterial blood pressure.

Substance P in the blood plasma in hypophysial portal vessels.

The aim of the present study was to check if Substance P (SP) is released from the hypothalamus into the hypophysial portal vessels and by this route exerts its direct influence on the adenohypophysis. For this purpose SP radioimmunoactivity was assayed in the blood plasma collected from hypophysial portal vessels and from the cephalic end of the external jugular vein. The SP levels in blood plasma collected from hypophysial portal vessels and from the jugular vein do not differ significantly. Neither does application of a noxious factor, such as bilateral femoral bone fracture, change significantly the SP level in the blood plasma from portal vessels and from the jugular vein. Hypoxia seems to increase the SP level in portal blood plasma and may be followed by its decrease. It is concluded that hypothalamic SP is not released into the hypophysial portal vessels under normal conditions and its direct influence on the adenohypophysis is not mediated this way.