Oxidative stress in very low birth weight infants as measured by urinary 8-OHdG

Very low birth weight (VLBW) infants can be subjected to oxidative stress in the course of intensive care. We measured 8-hydroxydeoxyguanosine (8-OHdG), a biomarker of oxidative stress, and estimated the degree of oxidative stress in such infants. We also examined if the administered oxygen was related to oxidative stress. Urine samples of 50 Japanese VLBW infants [birth weights: 956.3+/-277.6g, and gestational ages: 28.0+/-2.6 weeks (mean +/- SD)] were collected on various postnatal days and 8-OHdG levels were determined using an ELISA kit. Sixteen term infants served as normal controls. As body weights at sampling increased, the average levels of urinary 8-OHdG decreased. 8-Hydroxydeoxyguanosine levels were: infants under 1000g, 29.5+/-16.4 micromol/mol creatinine (n = 24); 1000-1500g, 23.8+/-14.9 (n = 12); over 1500g, 16.1+/-8.5 (n = 14); and control, 10.9+/-7.2 (n = 16). Significant differences were found between <1000g group and > or = 1500g group (p = 0.0030), <1000g group and control (p < 0.0001), and 1000-1500g group and control (p = 0.0108). Also as postconceptional age at sampling increased, the average levels of 8-OHdG decreased. 8-Hydroxydeoxyguanosine levels were: infants before 252 days (36 weeks) of postconception: 27.4+/-15.5 micromol/mol creatinine (n = 34); after 252 days, 18.2+/-12.5 (n = 16). Differences between <252 days group and control (p < 0.0001), and <252 days group and > or = 252 days groups (p = 0.0253) were statistically significant. Among the three groups based on ambient oxygen concentration (21%, 22-29%, and > or = 30%) there was no significant difference (p = 0.417). The more premature the infants were, the more intense was the oxidative stress, hence, it is the prematurity rather than the administered oxygen which causes oxidative stress in VLBW infants. Drury et al. ["Urinary 8-hydroxydeoxyguanosine in infants and children" Free Radic. Res. 28 (1998) 423-4281 measured urinary 8-OHdG of 28 infants (24-40 weeks gestation) and found no gestation or birthweight related differences. This discrepancy seemed to be because of difference in birth weights and sampling period of the subjects.     

Oxidative stress in newborn infants with and without asphyxia as measured by plasma antioxidants and free fatty acids

A rapid perfusion of oxygen in infants at birth may cause an increase of oxidative stress. To assess this possibility, we measured levels of blood plasma antioxidants and free fatty acids in 20 normal infants at 0, 1, 3, and 5 days after birth. Plasma levels of the most reactive antioxidant, ascorbic acid, decreased daily to equilibrium values at days 3 and 5. Percentages of oxidized form of coenzyme Q-10 (%CoQ-10) in total coenzyme Q, another good marker of oxidative stress, in infants (25-31%) were significantly higher than those in healthy young adults (4.5%). Plasma levels of total free fatty acids (FFA) in normal infants were highest at day 1 and decreased rapidly thereafter. The content of polyunsaturated fatty acids (PUFA) in total FFA was lowest at day 1 and then increased. Since PUFA are susceptible to oxidation, these changes in FFA composition suggest that oxidative stress is most evident at the initial day of neonatal life. Furthermore, it appears that mono-unsaturated fatty acids such as oleic and palmitoleic acids increase in response to the oxidative loss of PUFA. Similar changes in plasma antioxidants, FFA levels, and FFA compositions were observed in 9 infants with asphyxia. Values of %CoQ-10 in infants with asphyxia were significantly greater than those in normal infants, suggesting that infants with asphyxia have elevated oxidative stress.     

Oxypurinol improves coronary and peripheral endothelial function in patients with coronary artery disease

Coronary endothelial dysfunction is a powerful prognostic marker in patients with coronary artery disease (CAD) that is centrally related to oxidative inhibition of nitric oxide (NO)-dependent vascular cell signaling. Xanthine oxidase (XO), which both binds to and is expressed by endothelial cells, generates superoxide and hydrogen peroxide upon oxidation of purines. Whether inhibition of xanthine oxidase activity results in improved coronary vasomotor function in patients with CAD, however, remains unknown. We assessed coronary and peripheral (brachial artery) endothelial function in 18 patients (pts; 65+/-8 years, 86% male) with angiographically documented CAD, preserved left ventricular function, and non-elevated uric acid levels (233+/-10 microM). Patients received incremental doses of intracoronary acetylcholine (ACh; 10(-7) to 10(-5) microM), and minimal lumen diameter (MLD) and coronary blood flow (CBF) were assessed before and after intravenous administration of oxypurinol (200 mg). Oxypurinol inhibited plasma XO activity 63% (0.051+/- 0.001 vs 0.019+/- 0.005 microU/mg protein; p<0.01). In pts who displayed endothelial dysfunction as evidenced by coronary vasoconstriction in response to ACh (n=13), oxypurinol markedly attenuated ACh-induced vasoconstriction (-23+/- 4 vs -15+/- 4% at ACh 10(-5) microM, p<0.05) and significantly increased CBF (16+/-17 vs 62+/-18% at ACh 10(-5) microM, p<0.05), whereas in patients with preserved coronary endothelial function, oxypurinol had no effect on ACh-dependent changes in MLD (+2.8+/- 4.2 vs 5.2+/- 0.7%, p>0.05) or CBF (135+/-75 vs 154+/-61%, p>0.05). Flow-mediated dilation of the brachial artery, assessed in eight consecutive patients, increased from 5.1+/-1.5 before to 7.6+/-1.5% after oxypurinol administration (p < 0.05). Oxypurinol inhibition of XO improves coronary vascular endothelial dysfunction, a hallmark of patients with CAD. These observations reveal that XO-derived reactive oxygen species significantly contribute to impaired coronary NO bioavailability in CAD and that XO inhibition represents an additional treatment concept for inflammatory vascular diseases that deserves further investigation.     

Paraoxonase gene Gln192Arg (Q192R) polymorphism is associated with coronary artery spasm

We recently reported that oxidative stress is involved in the pathogenesis of coronary spasm. We hypothesized that oxidative-stress-related genetic factors and certain polymorphisms in the paraoxonase gene (PON1) and platelet-activating factor acetylhydrolase (PAF-AH) might influence the pathogenesis of coronary spasm. We therefore examined the possible association between the PON1 Q192R or PAF-AH V279F polymorphisms and coronary spasm in 214 patients with coronary spasm and 212 control subjects. Genotypes were determined by polymerase chain reaction/restriction fragment length polymorphism analysis. The incidence of the PON1-192R allele was significantly higher in the coronary spasm group than in the control group (65% vs 53%; P=0.0005). The PAF-AH-279F allele was not associated with coronary spasm (15% vs. 16%; P=0.8781). Multiple logistic regression analysis with forward stepwise selection involving the PON1-192R allele and the environmental risk factors revealed that the most predictive independent risk factor for coronary spasm was the PON1-192R allele (significance=0.0016, OR=2.52), followed by cigarette smoking (significance=0.0007, OR=2.01). We also measured plasma levels of TBARS (thiobarbituric acid-reactive substances) as a marker of oxidative stress. TBARS levels were higher in R/R types than in Q/Q types (2.115+/-0.086 nmol/ml [ n=25] vs 1.676+/-0.102 nmol/ml [ n=11], P<0.01). Thus, there is a significant association between the PON1-192R allele and coronary spasm; the PON1-192R allele may play an important role in the genesis of coronary spasm, probably by attenuating the suppression of oxidative stress.     

Progesterone, 17-OH-progesterone, androstenedione and testosterone plasma levels in spermatic venous blood of normal men and varicocele patients

Progesterone (P), 17-OH-progesterone (17-OH-P), Androstenedione (delta 4) and testosterone (T) plasma levels were measured in spermatic venous blood of twenty-nine varicocele patients (V) and in twelve normal subjects (N). Our data reveal a significant decrease of the mean testosterone in the spermatic blood of varicocele patients with respect to normal controls: (N = 1708.7 +/- 223.8 (SEM) nmol/l, n = 10. V = 1190.9 +/- 101.1 (SEM) nmol/l, n = 29. P less than 0.03). An inverse correlation has been observed between the age of varicocele patients and 17-OH-P (n = 29. y = -33.38x + 1384.70, r = -0.59, P less than 0.01) and delta 4 values (n = 23, y = -1.62x + 85.65, r = -0.49, P less than 0.05). The 17-OH-P/delta 4 ratio appears significantly augmented in varicocele patients with respect to normal controls (n = 4.80 +/- 0.86 (SEM), n = 12. V = 9.65 +/- 1.21 (SEM), n = 23.0.02 greater than P greater than 0.01). This indicates a deficiency in varicocele patients of 17-20 lyase activity. The positive correlation between the P/17-OH-P ratio and age of varicocele patients (n = 28, y = 0.007 x -0.090, r = 0.45, P less than 0.03) suggests a progressive impairment of 17-alpha-hydroxylase in such patients as they grow relatively older. These data demonstrated that the reduced spermatic levels of testosterone in varicoceles are due to the enzymatic impairment of testosterone biosynthesis, concerning firstly 17-20 lyase activity and secondly 17-alpha-hydroxylase activity. The latter enzymatic impairment is age related as is seen from the significant increase of the P/17-OH-P ratio in older patients.     

Recombinant human interleukin-1 beta: new possibilities for the prophylaxis and correction of toxic myelodepression in patients with malignant tumors. I. Phase I-II clinical trials of recombinant human interleukin-1 beta as a leukopoiesis stimulator in cancer patients receiving combination chemotherapy.

Human recombinant interleukin-1 beta (IL-1beta), administered by intravenous drop infusion, at doses of 10-20 ng/kg daily over 5 days, to a group of 67 patients suffering from malignant tumors and with grade II-IV toxic leukopenia, caused an increase in the leukocyte count to the normal value, within, on average, 8 +/- 1 days. The leukostimulatory effect of IL-1beta, administered subcutaneously at an average dose of 4.6 +/- 0.3 ng/kg (n = 16), appeared to be almost equal to that found for intravenous drop infusion at a dose of 10-20 ng/kg (n = 67). In patients receiving subcutaneous IL-1beta injections, the peripheral blood total leukocyte and granulocyte counts achieved normal values within 9 days. The side effects of IL-1beta at a dose of 0.1-20.0 ng/kg were well tolerated.     

Donor heart preservation with iloprost supplemented St. Thomas Hospital cardioplegic solution in isolated rat hearts

This study was designed to assess the influence of St. Thomas Hospital cardioplegic solution (St. Th.) on heart preservation in rat hearts subjected to 6h ischemia when supplemented with iloprost. In the control group (n=8), nothing was added to St. Th., whereas 10 or 1000 nmol L(-1) iloprost was added in the second (n=7) and third (n=8) groups, respectively. Mechanical contraction parameters, cardiac tissue damage and oxidative stress markers were evaluated. The 10 nmol/L iloprost group peak systolic pressure (71.0+/-30.9 versus 41.0+/-9.4 mm Hg) and -dp/dtmax (1103.8+/-94.3 versus 678.6+/-156.8 mm Hg s(-1)) were significantly higher than control group at 30 min of reperfusion (p<0.05). Iloprost supplemented groups had higher GSH and catalase levels of coronary perfusate at reperfusion, in comparison with initial values (p<0.05). AST, CK, CK-MB values increased at 0 min of reperfusion and cTnI values at 45 min of reperfusion (p<0.05) in all groups with no difference between groups. According to our results, iloprost supplementation had mild but significant improvement in postischemic values in mechanical and oxidative stress parameters, resulting in better heart preservation.     

Asymmetric dimethylarginine, oxidative stress, and vascular nitric oxide synthase in essential hypertension

We reported impaired endothelium-derived relaxation factor/nitric oxide (EDRF/NO) responses and constitutive nitric oxide synthase (cNOS) activity in subcutaneous vessels dissected from patients with essential hypertension (n = 9) compared with normal controls (n = 10). We now test the hypothesis that the patients in this study have increased circulating levels of the cNOS inhibitor, asymmetric dimethylarginine (ADMA), or the lipid peroxidation product of linoleic acid, 13-hydroxyoctadecadienoic acid (HODE), which is a marker of reactive oxygen species. Patients had significantly (P < 0.001) elevated (means +/- SD) plasma levels of ADMA (P(ADMA), 766 +/- 217 vs. 393 +/- 57 nmol/l) and symmetric dimethylarginine (P(SDMA): 644 +/- 140 vs. 399 +/- 70 nmol/l) but similar levels of L-arginine accompanied by significantly (P < 0.015) increased rates of renal ADMA excretion (21 +/- 9 vs. 14 +/- 5 nmol/mumol creatinine) and decreased rates of renal ADMA clearance (18 +/- 3 vs. 28 +/- 5 ml/min). They had significantly increased plasma levels of HODE (P(HODE): 309 +/- 30 vs. 226 +/- 24 nmol/l) and renal HODE excretion (433 +/- 93 vs. 299 +/- 67 nmol/micromol creatinine). For the combined group of normal and hypertensive subjects, the individual values for plasma levels of ADMA and HODE were both significantly (P < 0.001) and inversely correlated with microvascular EDRF/NO and positively correlated with mean blood pressure. In conclusion, elevated levels of ADMA and oxidative stress in a group of hypertensive patients could contribute to the associated microvascular endothelial dysfunction and elevated blood pressure.     

Impaired microvascular reactivity and endothelial function in patients with Cushing's syndrome: influence of arterial hypertension

The aim of the study was to evaluate skin microvascular reactivity (MVR) and possible influencing factors (fibrinolysis, oxidative stress, and endothelial function) in patients with Cushing's syndrome. Twenty-nine patients with active Cushing's syndrome (ten of them also examined after a successful operation) and 16 control subjects were studied. Skin MVR was measured by laser Doppler flowmetry during post-occlusive (PORH) and thermal hyperemia (TH). Malondialdehyde and Cu,Zn-superoxide dismutase were used as markers of oxidative stress. Fibrinolysis was estimated by tissue plasminogen activator (tPA) and its inhibitor (PAI-1). N-acetyl-beta-glucosaminidase, E-selectin, P-selectin, and ICAM-1 were used as markers of endothelial function. Oxidative stress and endothelial dysfunction was present in patients with hypercortisolism, however, increased concentration of ICAM-1 was also found in patients after the operation as compared to controls (290.8+/-74.2 vs. 210.9+/-56.3 ng.ml(-1), p<0.05). Maximal perfusion was significantly lower in patients with arterial hypertension during PORH and TH (36.3+/-13.0 vs. 63.3+/-32.4 PU, p<0.01, and 90.4+/-36.6 vs. 159.2+/-95.3 PU, p<0.05, respectively) and similarly the velocity of perfusion increase during PORH and TH was lower (3.2+/-1.5 vs. 5.2+/-3.4 PU.s(-1), p<0.05, and 0.95+/-0.6 vs. 1.8+/-1.1 PU.s(-1), p<0.05, respectively). The most pronounced impairment of microvascular reactivity was present in patients with combination of arterial hypertension and diabetes mellitus.     

The role of acute wall recoil and late restenosis: results of the OCBAS trial (Optimal Coronary Balloon Angioplasty with Provisional Stenting versus Primary Stent)

Early deterioration of minimal luminal diameter immediately after PTCA, has been associated with an increase of late restenosis. Lesions with no early loss after PTCA have a low restenosis rate. Coronary stents reduce restenosis in lesions exhibiting early wall recoil. The purpose of the OCBAS study was to compare two strategies during coronary interventions; provision vs. elective stenting. 116 patients with good PTCA results were randomized to stent (n = 57) or to optimal PTCA (n = 59). After randomization in PTCA group, 13.5% of the patients crossed over to stent due to early loss (provisional stenting). Baseline demographic and angiographic characteristics were similar in both groups of patients. At 7.6 months, 96.6% of the entire population had a follow-up angiographic study; 98.2% in the stent and 94.9% in the PTCA group. Immediate and follow-up angiographic data showed that acute gain was significantly higher in the stent than in the PTCA group (1.95 vs. 1.5 mm; P < 0.03). However, late loss was significantly higher in the stent than the PTCA groups (0.63 +/- 0.59 vs. 0.26 +/- 0.44, respectively; P = 0.01). Hence, net gain with both techniques was similar (1.32 +/- 0.3 vs. 1.24 +/- 0.29 mm for the stent and PTCA groups respectively; P = NS). Angiographic restenosis rate at follow-up (19.2% in stent vs. 16.4% in PTCA; P = NS) and TVR (17.5 in stent vs. 13.5% in PTCA; P = NS) were also similar. Furthermore, event-free survival was 80.8% in the stent versus 83.1% in the PTCA group (P = NS). Overall costs (hospital and follow-up) were US$591,740 in the stent versus US$398,480 in the PTCA group (P < 0.02). The strategy of the PTCA with delay angiogram and provisional stent if early loss occurs, had similar restenosis rate and TVR than universal use of bare stents.     

Enhanced accumulation of the isoprostane, 8-epi-PGF2 alpha,in human aortic and pulmonary valves of patients with coronary heart disease

The aim of the present study was to investigate whether the isoprostane 8-epi-PGF2 alpha differently accumulates in semilunar valves of patients suffering from coronary heart disease (CHD, n = 19) as compared to valves from healthy heart donors (controls, n = 6). Sections from isolated aortic and pulmonary valves were analyzed by semiquantitative immunohistochemistry. The 8-epi-PGF2 alpha-content was determined by using a specific radioimmunoassay. The accumulation of 8-epi-PGF2 alpha in both valves was higher in CHD-patients in comparison to controls (Aortic valves: 36.49 +/- 11.26% vs. 15.78 +/- 3.04%; pulmonary valves: 46.79 +/- 9.80% vs. 14.99 +/- 3.57%). The results from the radioimmunoassay revealed comparable findings in both groups (CHD vs. controls: 395.95 +/- 86.09 vs. 139.50 +/- 47.46 pg/mg protein in the aortic valves and 430.47 +/- 76.30 vs. 147.33 +/- 53.84 pg/mg protein in pulmonary valves). Pulmonary valves seem to be more susceptible to oxidative stress than aortic valves as evidenced by a higher accumulation of 8-epi-PGF2 alpha in CHD patients. Considering the data presented in this study, we suggest that 8-epi-PGF2 alpha is a valuable indicator of oxidative injury in human semilunar valves.     

High incidence of hyperandrogenism-related clinical signs in patients with multiple sclerosis

A mild prevalence of multiple sclerosis (MS) is present in females (2:1). To elucidate the pathogenetic role of sex steroids on the disease, we studied 76 women affected by MS, compared to 50 healthy women (mean age +/- SD, 34.9 +/- 0.9 vs. 33.4 +/- 1.7 years). The menarche was at mean age of 12.3 +/- 0.2 vs. 12.4 +/- 0.2. Interval between menses was 28.0 +/- 0.3 vs 27.8 +/- 0.3 days, with duration of menstrual flow of 5.0 +/- 0.2 vs. 5.0 +/- 0.2 days. Oligo- or amenorrhea was present in 20% of patients and in 16% of controls. Oral contraceptives were assumed by 21% of patients and 34% of controls (n.s.). Premenstrual symptoms were found in 43% of patients and in 46% of controls (n.s.). The incidence of hyperandrogenism (greasy skin, acne and hirsutism), evaluated by a specific questionnaire, was higher and statistically significant in MS patients than in controls (28% vs. 10%, p<0.05). Further studies, including a complete clinical and laboratory evaluation of gonadal function, are necessary in order to clarify whether hyperandrogenism may influence MS disease activity.     

Effects of taurolidine and octreotide on tumor growth and lipid peroxidation after staging-laparoscopy in ductal pancreatic cancer

Irrigation with taurolidine after laparoscopy decreases tumor growth in colon carcinoma. In pancreatic cancer subcutaneous therapy with octreotide decreases oxidative stress and carcinogenesis as well. However, it is still unclear, whether irrigation with taurolidine or octreotide after laparoscopic pancreatic biopsy reduces tumor growth in pancreatic cancer as well. In 60 Syrian hamsters ductal pancreatic adenocarcinoma was induced by weekly injection of 10mg/kg body weight N-nitrosobis-2-oxopropylamine s.c. for 10 weeks. In week 16 laparoscopic pancreatic biopsy by use of carbon dioxide was performed (gr. 1, n = 20) with subsequent laparoscopic irrigation with taurolidine (gr. 2, n = 20) or octreotide (gr. 3, n = 20). In week 25 hamsters were sacrificed. Our results show that macroscopic visible primary tumors were found in only one animal of the taurolidine group (5.9%), compared to 42.1% in the saline and 62.5% in the octreotide group (P<0.05). Carcinomas were smaller after saline (6+/-23 mm(2)) than after octreotide irrigation (70+/-120 mm(2), P<0.05). In conclusion this study showed that laparoscopic irrigation with taurolidine after pancreatic biopsy inhibited tumor growth in ductal pancreatic adenocarcinoma.     

Blood glutathione redox status in gestational hypertension

Gestational hypertension during the third trimester reflects an exaggerated maternal inflammatory response to pregnancy. We hypothesized that oxidative stress present even in normal pregnancy becomes uncompensated in hypertensive patients. A glucose-6-phosphate dehydrogenase (G6PD) activity sufficient to meet the increased reductive equivalent need of the cells is indispensable for defense against oxidative stress. The erythrocyte glutathione redox system was studied, where G6PD is the only NADPH source. The glutathione (GSH) redox status was measured both in vivo and after an in vitro oxidative challenge in pregnant women with gestational hypertension (n = 19) vs. normotensive pregnant subjects (n = 18) and controls (n = 20). An erythrocyte GSH depletion with an increase in the oxidized form (GSSG) resulted in an elevated ratio GSSG/GSH (0.305 +/- 0.057; mean +/- SD) in hypertensive pregnant women vs. normotensive pregnant or control subjects (0.154 +/- 0.025; 0.168 +/- 0.073; p <.001). In hypertensive pregnant patients, a "GSH stability" decrease after an in vitro oxidative challenge suggested a reduced GSH recycling capacity resulting from an insufficient NADPH supply. The erythrocyte GSSG/GSH ratio may serve as an early and sensitive parameter of the oxidative imbalance and a relevant target for future clinical trials to control the effects of antioxidant treatment in women at increased risk of the pre-eclampsia syndrome.     

The effects of different doses of atorvastatin on plasma endothelin-1 levels in type 2 diabetic patients with dyslipidemia

We investigated the effects of three different daily doses (10 mg, 20 mg, and 40 mg) of atorvastatin, a relatively new and potent statin, on plasma endothelin (ET)-1 and highly sensitive C-reactive protein (CRP) levels in type 2 diabetic subjects. Twenty-nine type 2 diabetic patients with dyslipidemia were enrolled and randomly assigned to receive atorvastatin orally at 10 mg (A10; n = 10), 20 mg (A20; n = 10), or 40 mg (A40; n = 9) daily for 12 weeks. Levels of plasma total cholesterol and low-density lipoprotein (LDL)-cholesterol (C) in all three studied groups were significantly decreased after treatment with atorvastatin for 12 weeks (all groups, P < 0.001). However, the greatest LDL-C lowering effect and the highest percentage of subjects achieving the National Cholesterol Education Program's Adult Treatment Panel III (NCEP-ATP III) LDL-C goal were observed in the A20 group. All diabetic subjects had a higher plasma ET-1 concentration (A10, 1.02 +/- 0.37 pg/ml, mean +/- SD; A20, 1.17 +/- 0.55 pg/ml; and A40, 0.87 +/- 0.45 pg/ml) than that of age- and sex-matched normal control subjects (0.64 +/- 0.15 pg/ml; all groups, P < 0.001). Plasma ET-1 levels showed a borderline significant decrease at the end of study, by 22% in diabetic subjects treated with 10 mg atorvastatin (P = 0.05 compared with baseline), and by 30% in subjects treated with 20 mg atorvastatin (P = 0.06, compared with baseline). Paradoxically, the 40-mg dose of atorvastatin provided an increase of 2% in plasma ET-1 levels at the end of study, which is significantly different (P < 0.05) and marginally significant (P = 0.057) from the levels of the 10- and 20-mg doses, respectively. Similarly, although insignificantly, plasma concentrations of CRP also tended to decrease by 12% and 48%, and paradoxically increased by 18% in diabetic patients treated with 10 mg, 20 mg, and 40 mg atorvastatin, respectively. The clinical significance of these biphasic lipid-independent statin effects is unknown and the present study suggests that 20 mg atorvastatin may have the best benefits in treating diabetic patients with dyslipidemia.     

Increased urinary 1,N6-ethenodeoxyadenosine and 3,N4-ethenodeoxycytidine excretion in thalassemia patients: markers for lipid peroxidation-induced DNA damage

Thalassemic diseases including homozygous beta-thalassemia and beta-thalassemia/Hb E (beta-Thal/Hb E) are prevalent in Southeast Asia. Iron overload is a common complication in beta-thalassemia patients which induces intracellular oxidative stress and lipid peroxidation (LPO). LPO end products generate miscoding etheno adducts in DNA which after their repair are excreted in urine. We investigated whether urinary levels of 1,N6-ethenodeoxyadenosine (epsilondA) and 3,N4-ethenodeoxycytidine (epsilondC) can serve as putative cancer risk markers in beta-Thal/Hb E patients. epsilondA and epsilondC levels were assayed in collected urine samples by immunoprecipitation-HPLC-fluorescence and 32P-postlabeling TLC, respectively. Mean epsilondA (fmol/micromol creatinine) levels in urine of beta-Thal/Hb E patients ranged from 4.8 to 120.4 (33.8+/-3.9; n=37) and were 8.7 times higher compared to asymptomatic controls (1.4-13.8; 3.9+/-0.8; n=20). The respective epsilondC levels ranged from 0.15 to 32.5 (5.2+/-1.3; n=37) and were increased some 13 times over controls (0.04-1.2; 0.4+/-0.7; n=20). epsilondC levels were correlated positively with NTBI (r=0.517; P=0.002), whereas epsilondA showed only a trend (r=0.257; P=0.124). We conclude that the strongly increased urinary excretion of etheno adducts indicates elevated LPO-induced DNA damage in internal organs such as the liver. These highly promutagenic lesions may contribute to the increased risk of thalassemia patients to develop hepatocellular carcinoma.     

Oxidation-reduction potential and paraoxonase-arylesterase activity in trauma patients

The amount of oxidative stress in severely traumatized patients is usually based on various individual parameters such as total antioxidants and lipid peroxidation. Serial measurements of plasma oxidation-reduction potential (ORP) in severely traumatized patients as a simple mean of assessing overall oxidative stress is described. Serial whole blood samples were obtained from multi-trauma patients (N=39) and healthy individuals (N=10). Plasma ORP in multi-trauma patients increased during the first few days of hospitalization and approached normal ORP levels upon discharge. On the ORP maxima day (5.8 days+/-0.5 SEM), a statistically significant decrease (p<0.05) was observed for negative acute phase reactants such as plasma paraoxonase-arylesterase (PON-AE) activity and total plasma protein in comparison with admission plasma levels. Monitoring ORP could be a useful tool for assessing the degree of oxidative stress, inflammation, severity of injury, and potential efficacy of treatment.     

Selenium, glutathione peroxidases, and some other antioxidant parameters in blood of patients with chronic renal failure

In the present study several parameters associated with oxidative stress were examined in the blood of 25 chronic renal failure (CRF) patients and the results were compared with 18 healthy subjects. Mean creatinine concentration in patients was 1,216 +/- 292 micromol/l. Selenium (Se) concentration in red cells, whole blood and in plasma of CRF patients (106 +/- 32.5, 59.0 +/- 16.7 and 42.4 +/- 13.8 ng/ml, respectively) was significantly (0.0001 < P 0.01) lower (by 20-42%) compared with the controls. Red cell and plasma glutathione peroxidase (GSH-Px) activities (16.6 +/- 3.4 U/g Hb and 93.7 +/- 32.9 U/l plasma) were lower by 12 and 53% (P < 0.05 and < 0.0001, respectively) in patients than in healthy subjects. GSH concentration in red cells of patients (2.81 +/- 0.45 mmol/l) was significantly (P < 0.001) higher (by 20%) than in control group. Malonyldialdehyde (MDA) concentration (expressed as thiobarbituric acid-reactive substances) in red cells of patients (725 +/- 155 nmol/g Hb) was significantly (P < 0.001) higher (by 28%) than in control group. No significant difference was observed in the activity of superoxide dismutase in pLasma between the two groups. In conclusion, our results confirm that the aLterations in Se levels in blood components and in GSH-Px activity in plasma show that the kidney plays an important role in Se homeostasis and in plasma GSH-Px synthesis.     

Clinical evidence for myocardial derecruitment downstream from severe stenosis: pressure-flow control interaction

To verify the interaction between coronary pressure (CP) and blood flow (CBF) control, we studied nine candidates for angioplasty of an isolated lesion of the left anterior descending coronary artery [i.e. , percutaneous transluminal coronary angioplasty (PTCA)]. CBF (i.e., flow velocity x coronary cross-sectional area at the Doppler tip) and CP were monitored during washout of 2-5 mCi of (133)Xe after bolus injection into the left main artery before and after PTCA. Xe mean transit time (MTT) was calculated as the area under the time-activity curve, acquired by a gamma camera, divided by the dose obtained from a model fit of the Xe curve in the anterior wall. CBF response to intracoronary adenosine (2 mg) was also assessed. PTCA increased baseline CBF (from 14.5 +/- 9.4 to 20 +/- 8 ml/min, P < 0.01), coronary flow reserve (from 1.52 +/- 0.24 to 2.33 +/- 0.8, P < 0.01), and CP (from 64 +/- 9 to 100 +/- 10 mmHg, P < 0.05). MTT decreased from 89 +/- 32 to 70 +/- 19 s (P < 0.05) after PTCA; however, MTT and CBF changes were not correlated (r = -0.09, not significant). Inasmuch as MTT is the ratio of distribution volume to CBF, MTT x CBF was used as an index of perfused myocardial volume. Volume increased after PTCA from 23 +/- 18 to 56 +/- 30 ml. A direct correlation was observed between the percent increase in distal CP and percent increase in perfused volume (r = 0.91, P < 0.01). Thus low CP was not associated with exhaustion of flow reserve but, rather, with reduction of perfused myocardial volume. These data suggest that, in the presence of a severe coronary stenosis, derecruitment of vascular units occurs that is proportional to the decrease in driving pressure. Residual perfused units maintain a vasomotor tone, thus explaining the paradoxical persistence of coronary reserve.     

Coronary endothelial dysfunction is not rapidly reversible with ascorbic acid

In humans with cardiovascular risk factors, increased vascular production of superoxide anion may contribute to endothelial dysfunction by its reacting with nitric oxide and reducing its biological activity. High concentrations of ascorbic acid scavenge superoxide anion and restore normal endothelium-dependent vasodilation in humans with cardiovascular risk factors. To investigate the contribution of increased superoxide anion to endothelial dysfunction in atherosclerotic coronary arteries, we examined the effect of sequential infusions of ascorbic acid (final concentration 0.1, 1.0, and 10 mmol/L) or placebo on coronary endothelial function in 26 subjects referred for cardiac catheterization to evaluate coronary artery disease. Coronary vasomotor function was evaluated using intracoronary agonist infusion, quantitative angiography, and intracoronary Doppler measurements. At baseline, endothelium-dependent vasodilation of epicardial arteries and coronary microvessels was impaired to an equivalent extent in the ascorbic acid and placebo groups. Sequential ascorbic acid infusions had no effect on the acetylcholine-induced change in coronary artery diameter (-11+/-8, -12+/-10, and -9+/-9%) compared with the effect of placebo (-14+/-13, -16+/-10, and -13+/-9%) infusions (p=0.98). Similarly, the changes in coronary blood flow during acetylcholine infusions were equivalent during ascorbic acid (51+/-44, 67+/-66, and 62+/-52%) and placebo (61+/-104, 55+/-93, and 50+/-69%) infusions (p=0.63). Ascorbic acid also had no effect on the dilator response to intracoronary nitroglycerin (p=0.19). These data argue against an important role for superoxide-mediated "inactivation" of nitric oxide or another rapidly reversible form of oxidative stress as a mechanism of coronary endothelial dysfunction in patients with coronary atherosclerosis.