Urinary oxalate to creatinine ratios in healthy Turkish schoolchildren.

AIM: we aimed to establish reference values for urinary oxalate to creatinine ratios in healthy children aged 6-15 years and to investigate the relationship between their nutritional habits and oxalate excretion. MATERIALS AND METHODS: Random urine specimens from 953 healthy children aged 6-15 years were obtained and analyzed for oxalate and creatinine. Additionally, a 24-h dietary recall form was prepared and given to them. The ingredient composition of the diet was calculated. The children were divided into three groups according to age: Group I (69 years, n = 353), Group II (10-12 years, n = 335), and Group III (13-15 years, n = 265). RESULTS: The 95th percentile of the oxalate to creatinine ratio for subjects aged 6-9, 10-12, and 13-15 years were 0.048, 0.042, and 0.042 mg/mg, respectively. The oxalate to creatinine ratio was significantly higher in Group 1 than in Group 2 and Group 3. Urinary oxalate excretion was positively correlated with increased protein intake and negatively correlated with age. A significant positive correlation was determined between urinary oxalate excretion and the proline, serine, protein, and glycine content of diet. Dietary proline intake showed a positive correlation with the urine oxalate to creatinine ratio and was found to be an independent predictor for urinary oxalate. CONCLUSIONS: These data lend support to the idea that every country should have its own normal reference values to determine the underlying metabolic risk factor for kidney stone disease since regional variation in the dietary intake of proteins and other nutrients can affect normal urinary excretion of oxalate.

Increased serum asymmetric dimethylarginine level is an independent predictor of contrast-induced nephropathy.

OBJECTIVES: The aim of our study was to evaluate whether serum asymmetric dimethylarginine (ADMA) level is an independent predictor of contrast-induced nephropathy (CIN). STUDY DESIGN: The study involved 90 consecutive patients with stable angina pectoris who underwent coronary angiography and ventriculography. Baseline serum creatinine (SCr) levels ranged between ≥1.2 and <2 mg/dl. All patients were hydrated with intravenous isotonic saline at a rate of 1 ml/kg per hour for 6 hours before and 12 hours after the procedure. The primary end point was the occurrence of CIN. The secondary end point was the change in SCr levels at day 2 after the contrast exposure. Serum ADMA was determined by the ELISA method. RESULTS: The CIN rate was 11.1%. We detected a statistically significantly higher serum ADMA level in the CIN(+) group compared to that of the CIN(-) group [210.6 ng/ml (115.6-217.2) vs. 91.5 ng/ml (65.2-122.1), p=0.01]. Mehran risk score and diabetes mellitus (DM) ratio were higher in the CIN(+) group compared to those values in the CIN(-) group [8 (5.75-10) vs. 5 (5-7), p=0.01 and 70% vs. 26.3%, p=0.01, respectively]. Serum ADMA level, Mehran risk score and DM were independent predictors of CIN (odds ratio (OR) 1.030, 95% confidence interval (CI) 1.011-1.050, p=0.002; OR 1.565, 95% CI 1.102-2.223, p=0.012; OR 9.422, 95% CI 1.441-61.598, p=0.019, respectively). A serum ADMA level of >124.7 ng/ml had 80% sensitivity and 76% specificity in predicting the development of CIN. In addition, we found a positive correlation between SCr change and serum ADMA level (p=0.001, r=0.35). CONCLUSION: Our study demonstrates that increased serum ADMA level is an independent predictor of CIN.

A novel approach in psoriasis: first usage of known protein oxidation markers to prove oxidative stress.

Oxidative stress may play a pivotal role in the pathogenesis of psoriasis, an inflammatory/hyperproliferative skin disease characterized by the cutaneous accumulation of neutrophils releasing reactive oxygen species, as revealed in a number of studies. This study was performed to demonstrate the presence of oxidative stress in psoriasis, as measured by protein oxidation markers. Twenty-nine psoriasis patients were selected based on disease severity assessment using body surface area as well as the psoriasis area severity index (PASI), and were grouped as mild (PASI ≤ 10) and moderate-to-severe (PASI > 10). The measured parameters in psoriatic patients and fourteen healthy volunteers were as follows: erythrocyte sedimentation rate (ESR), high sensitive C-reactive protein (CRP), myeloperoxidase (MPO) activity, neopterin, total lipid hydroperoxides (LHP), pyrrolized protein (PP), protein carbonyl compounds (PCC), advanced oxidation protein products (AOPP), thiol levels, along with complete blood count. Except lower thiols, all parameters were found to be higher in total patients as well as in subgroups, compared to controls. There was no significant difference among the subgroups. In conclusion, protein oxidation in psoriatics, not only in moderate-to-severe, but also in mild patients, may be explained by the findings of inflammation, phagocytic cell oxidation, and MPO-hypochlorous acid-oxidation reactions; as reflected by increased total/differential leucocytes counts, CRP, ESR as well as MPO, neopterin, AOPP, PCC, PP, LHP, and decreased thiol levels. Demonstrating the AOPP and PP formation for the first time, oxidants from active neutrophils/monocytes may play an important role in the pathogenesis of psoriasis, leading to oxidative stress, especially by protein oxidation.