Antioxidant signal and kidney injury molecule-1 levels in shockwave lithotripsy induced kidney injury.

PURPOSE: Shockwave lithotripsy (SWL) induces acute kidney injury (AKI) that extends from the papilla to the outer cortex by causing ischemia and the production of nephrotoxic agents. Direct ischemic damage and the generation of free radicals cause injury to the proximal tubular cells. Kidney injury molecule-1 (KIM-1) is a transmembrane glycoprotein that is upregulated in proximal tubular cells after ischemic or nephrotoxic injury and is not expressed in healthy kidneys. We evaluated the extent of free radical production in response to SWL by measuring urinary total antioxidant capacity (TAC) and total oxidant status (TOS). Furthermore, we investigated the severity of SWL-induced kidney injury by measuring KIM-1 expression levels. PATIENTS AND METHODS: The study population comprised 30 patients who were carefully selected and 30 age and sex matched control subjects. All patients received the same SWL procedure. Midstream urine samples were collected from patients before SWL and at 120 minutes after SWL. Urine KIM-1 levels were measured by enzyme-linked immunosorbent assay, and TAC and TOS were measured via spectrophotometry. RESULTS: Mean levels of TAC (2.88±0.56 mmolTxEq/L),TOS (8.27±1.57 µmolH2O2Eq/L), and KIM-1 (0.55±0.08 ng/mL) before SWL were not significantly different from mean TAC, TOS, and KIM-1 levels measured from the control group at 2.81±0.42 mmolTxEq/L, 10.73±1.4 µmolH2O2Eq/L, and 0.51±0.07 ng/mL, respectively. Two hours after SWL, mean urine TAC levels (2.81±0.85 mmolTxEq/L, P=0.02) were decreased and mean KIM-1 expression (0.85±0.11 ng/mL, P=0.01) was significantly increased, but there was no significant difference in mean TOS levels (11.24±1.9 µmolH2O2Eq/L, P=0.627) compared with the control group. CONCLUSIONS: The increased burden of free radical oxidants in the setting of decreasing antioxidant capacity may be one of the initial indicators of AKI after SWL. Moreover, KIM-1 demonstrates great potential as an early and noninvasive biomarker of SWL-induced kidney injury.

An evaluation of nitric oxide, folate, homocysteine levels and lipid peroxidation in postmenopausal osteoporosis.

OBJECTIVES: In the current study, the risk coefficients of nitric oxide (NO), folate, homocysteine levels and lipid peroxidation in postmenopausal osteoporotic women were determined. MATERIAL AND METHODS: Bone mineral density was determined by dual-energy X-ray absorptiometry. The levels of serum lipid peroxidation products such as the thiobarbituric acid adduct of malondialdehyde (MDA) were measured spectrophotometrically. Plasma folate and homocysteine (Hcy) levels were measured by enzyme chemiluminescence immunoassay. Plasma nitrite levels were measured with the Griess reaction RESULTS: The odds ratios and 95% Confidence Intervals (CI) of the variables MDA, folate, NO, body-mass index (BMI), menopause age and age were found significant. MDA, NO and folate variables were found statistically significant in the analysis of receiver operating charecteristic (ROCs). The areas under the curve (AUCs, 95% CI) of MDA, NO and folate were found to be statistically significant. CONCLUSIONS: The current study indicates that NO, MDA and folate are risk variables for postmenopausal osteoporosis.

Oxidative stress in smokers and non-smokers.

Oxidative stress plays an important role in the pathogenesis of some diseases such as lung cancer, chronic obstructive pulmonary disease, and atheroscleorosis. Smoking may enhance oxidative stress not only through the production of reactive oxygen radicals in smoke but also through weakening of the antioxidant defense systems. In this study, we investigated the effects of smoking on lipid peroxidation and paraoxonase activity in a healthy population. The study consisted of (n = 30) smokers and (n = 30) nonsmokers. The age of the population which is studied was 44.74 +/- 10.59 yr. The levels of serum malondialdehyde (MDA) and paraoxonase (PON1) activities were measured by the modified Buege method and the Eckerson method, respectively. Student's t-test was used to analyze the data. The serum MDA levels were significantly higher (p < .05) and serum PON1 activities were significantly lower (p < .001) in smokers than in nonsmokers. Thus, increased levels of serum MDA and decreased PON1 activities may be important in determining the oxidant/antioxidant imbalance in smokers.

Effect of ELF magnetic fields on lipid peroxidation, sperm count, p53, and trace elements.

BACKGROUND: Some epidemiological and laboratory studies suggest a possible connection between extremely low-frequency (ELF) magnetic fields and certain illnesses, such as cancer, immune suppression, as well as reproductive toxic effects and abnormalities. Therefore, the aim of this study was to investigate the effects of ELF magnetic fields (1.35 mT) on sperm count, malondialdehyde concentration, the histology of such organs as the testes, brain, liver, and kidney tissues, p53 immunoreactivity of bone marrow, and the serum concentrations of Cu2+, Zn2+, Mn2+, and Fe3+ in rats. MATERIAL/METHODS: Sixteen Sprague-Dawley male rats were divided into two groups. The rats in the experimental group were exposed to an ELF magnetic field 2 hr/day for 2 months (7 days a week). The rats in the control group were not exposed to the ELF magnetic field. The exposure was performed in a Faraday cage (130 x 65 x 80 cm) with grounded shielding against the electric component. The Mann-Whitney U-test was used for the statistical analysis of the data. RESULTS: Magnetic field measurements showed that, under the experimental conditions, the magnetic field-exposure system produced a stable flux density of 1.35+/-0.018 mT and a stable frequency of 50 Hz, with negligible harmonics and no transients. However, no statistically significant alteration was observed in the parameters measured in this study except in Mn2+ concentrations (p<0.001). CONCLUSIONS: The present study found no evidence of an adverse effect of ELF magnetic fields on the measured parameters except for significantly increased Mn2+ concentrations (p<0.001).

Trace elements and oxidative stress in chronic obstructive pulmonary disease.

OBJECTIVES: Many trace elements have activator or inhibitor roles in the antioxidative defense systems in diseases such as chronic obstructive pulmonary diseases (COPD). In this study, we aimed to show the levels of trace elements with action in oxidative stress, and to show the levels of malondialdehyde (MDA) as a marker of oxidative stress, and the activity of paraoxonase (PON1) as an antioxidant in COPD and smokers. METHODS: We included 25 patients with COPD, and 20 healthy non-smokers in the study. We selected them from the hospitalized patients at the Hospital of Dicle University, Turkey, between April 2003 and January 2004. The clinical condition of the patients was stable. RESULTS: The serum copper (Cu) and MDA concentrations in COPD patients were higher than the control group. There were no differences in zinc (Zn) concentration and Cu/Zn ratio between COPD patients and the control group. We found lower serum PON1 activities in COPD patients compared with the control group. There was no statistically significant difference in Zn concentration and Cu/Zn ratio between smokers and non-smokers in COPD. There were statistically significant differences in Cu, MDA concentrations and serum PON1 activities between smokers and non-smokers in COPD. CONCLUSION: We could suggest that trace elements such as Cu, oxidants and antioxidants such as MDA and PON1 have roles in oxidative stress, and in COPD.

Does biomass exposure affect serum MDA levels in women?

It is believed that the inhalation of biomass fuel, a substance that is used for bread baking and heating in rural areas, is associated with chronic obstructive pulmonary disease (COPD) and pulmonary symptoms. The products of biomass are claimed to affect the oxidant/antioxidant imbalance, which plays a significant role in such a disease COPD. In our study, the serum level of malonyldialdehyde (MDA) was accepted as a marker of oxidant/antioxidant imbalance, and it was measured by the thiobarbituric acid method. A total of 43 women living in the central and rural areas of Diyarbakir was chosen randomly for the study and they were divided into two groups. The first group, also called the study population, consisted of 28 women living in rural areas. The mean age of the sample was 43 yr (range 31-63 yr). All were healthy and nonsmokers. Among these women the mean duration of the exposure to biomass was 12 h/wk for 25 yr. The mean MDA level (+/-SD) was 3281 +/- 0.789 nmol/ml. The second group, the control population, consisted of 15 healthy women of age 42 yr (range 30-65 yr). They were again nonsmokers and healthy. These women were selected from the central Diyarbakir. The mean MDA level (+/-SD) was 1.474 +/- 0.630 nmol/ml. The difference between two populations were statistically significant (p < 0.0001). In conclusion, we believe that the high level of serum MDA in women is a result of biomass exposure.