Comparative study of two commercial enzymatic kits for determining oxalate concentrations in urine.

We performed a comparative study of two commercial kits for determining oxalate in urine. These were: (a) an oxalate decarboxylase-based assay (Boehringer Mannheim); (b) an oxalate oxidase-based assay (Sigma). The within-run and between-run imprecision were found to be similar in both methods. The recovery was 94% with the oxalate decarboxylase method. The pH of the specimen had a major effect on the recovery obtained by the oxalate oxidase method (66-86% at pH = 2.5 and 37-68% at pH = 1.5). The decarboxylase method was linear up to at least 2224 mumol/L and the oxidase method was linear up to at least 890 mumol/L. We also studied the interference of ascorbic acid in both techniques and found a positive bias with the oxidase method and a negative bias using the decarboxylase method. The correlation coefficient was 0.592.

Diet supplementation with vitamin E, vitamin C and beta-carotene cocktail enhances basal neutrophil antioxidant enzymes in athletes.

Exercise increases oxygen consumption and causes a disturbance of intracellular pro-oxidant-antioxidant homeostasis. Few data are available as to the cumulative effects of exercise on the antioxidant defenses of the neutrophil. We studied the effects of 90 days' supplementation with placebo or an antioxidant cocktail of vitamin E (500 mg/day) and beta-carotene (30 mg/day) and the last 15 days also with vitamin C (1 g/day) on sportsmen's basal neutrophil antioxidant defenses. We analyzed the activities of catalase, glutathione peroxidase, glutathione reductase and the activities and levels of superoxide dismutase, glutathione and glutathione disulfide in neutrophils purified from antecubital vein blood of sportsmen before and after diet supplementation. Plasma vitamin E, beta-carotene and vitamin C concentrations in the antioxidant-supplemented group were approximately 1.6, 10, and 1.2 times higher respectively than those of the placebo group. The antioxidant-supplemented group presented a significantly higher glutathione versus glutathione disulfide ratio in neutrophils (about 20%) than the placebo one. Antioxidant supplementation enhances the antioxidant enzyme activity of superoxide dismutase and catalase in neutrophils.

[Evaluation of the hematologic autoanalyzer Coulter Maxm]. / Evaluación del autoanalizador hematológico Coulter Maxm.

PURPOSE: To evaluate the performance of the Coulter MaxM autoanalyser, based on volume, cell conductivity and laser-beam dispersion, and to assess the automated leucocyte differential count (LDC). MATERIAL AND METHODS: A total number of 2,016 blood samples drawn on tri-K EDTA as anticoagulant were studied. The following data were analysed: 1-Intra- and inter-assay inaccuracy, the findings being expressed as mean and variation coefficient (CV%). 2- Correlation with the results attained with other systems (Coulter STKS and Technicon H1); The Pearson's correlation coefficient was used for this analysis. 3- Assessment of the morphologic suspect warning flags, optic microscope examination being used as reference. 4- Stability of the samples along time; the samples were analysed at 2, 6, 24 and 48 hours after withdrawal, and the Scheffe's test was used for comparison of results. 5- Performance speed. RESULTS: 1- The intra-assay inaccuracy was found acceptable for all the values except the basophil count (CV: 30.8%). The lack of reproducibility for basophil count is similar to that observed in the Coulter STKS system. 2- Correlation: Optimal LDC was found for neutrophils, eosinophils and lymphocytes. Excellent correlation with the Coulter STKS was seen except for haemoglobin, haematocrit and basophil count. The correlation with the Technicon H1 was better then with the STKS, except for basophil and monocyte counts. The correlation with basophil count was low with every system. 3- Warning flags appeared in 13.4% of the samples, the worse results corresponded to basophils, monocytes, stabs and atypical lymphocytes. 4- Samples stored at 4 degrees C for 24 hr had not significant variations in LDC. Those ones stored at 20-25 degrees C only showed significant variations after 24 hr in the monocyte count. 5- The working speed was 60 samples processed and printed in one hour. CONCLUSION: The Coulter MaxM autoanalyser is a useful machine for laboratories and provides a 5-class LDC plus a sound screen for leucocyte morphologic anomalies.

[Comparative study of the analyzers L-9100 (Merck-Hitachi) and HA-8121 (Menarini) for the determination of glycosylated hemoglobin]. / Estudio comparativo de los analizadores L-9100 (Merck-Hitachi) y HA-8121 (Menarini) para la determinación de hemoglobina glucosilada.

A comparison study about the determination of HbA1c by L-9100 (Merck Hitachi) and HA-8121 (Menarini) was made. HbA1c was measured by high pressure liquid chromatography (HPLC). The within-run imprecision was CV < 3% (for HA-8121) and CV < 4.9% (for L-9100). The between-run imprecision was CV < 1% (for L-9100) and CV < 2% (for HA-121). Analysis of means (Student test) showed that both instruments were statistically different for HbA1Ac measurements (p < 0.001). The results of regression analysis (Passsing-Bablock test) were as follows: y = 0.88x + 0.58 (y = L-9100, r = 0.982, p = 0.005). In conclusion, the results showed that there are statistical differences between both instruments. Regression and correlation was good, but the data also showed that there is a constant and proportional error. We must make a new reference range values.