Effects of thyroid hormone supplementation on oxidative stress after sleeve gastrectomy in rats

Aim: Sleeve gastrectomy has been used for the surgical treatment of morbid obesity. The aim of the present study was to determine the effects of triiodothyronine supplementation on oxidative stress parameters in anastomotic tissue level. Material and Methods: Twenty-four male Wistar albino rats were divided into control (n:12), and experimental (n:12) groups and underwent sleeve gastrectomy. Experimental group rats received a single dose of triiodothyronine (400 mg/100 g) in the operation day. Rats were sacrificed on postoperative day 7. Serum thyroid hormones were analysed. The supernatants were used to measure total oxidant status, total antioxidant status, nitric oxide and malondialdehyde levels. All tissue parameters were analysed by spectrophotometric methods. Oxidative stress index values were calculated. Results: Thyroid stimulating hormone levels in both the control and triiodothyronine group did not significantly change on the 7th postoperative day (p=0.663). Free triiodothyronine levels were significantly higher in triiodothyronine group rats than in control group rats (triiodothyronine vs control: p=0.004). Although total oxidant status levels did not altered by thyroid hormone treatment (p>0.05), total antioxidant status levels significantly decreased (p0.05). Tissue nitric oxide levels were also similar in both groups (p>0.05). Malondialdehyde levels increased in triiodothyronine given rats compared with the control group (p<0.01). Conclusion: This study showed that total oxidant status levels and oxidative stress index values were similar in both groups. However, triiodothyronine supplementation induced lipid peroxidation by increasing tissue malondialdehyde levels that might deplete tissue antioxidant level

Matrix Selection for Measurement of Zinc Levels

INTRODUCTION: Measurement of blood zinc levels is frequently used in the diagnosis of a few conditions such as growth retardation, immunodeficiency, infertility, neurological disorder, and acrodermatitis enteropathica. The serum matrix is the most preferred one to determine zinc levels due to the ease of analysis with other tests and cost-effectiveness of blood collection tubes used to obtain serum samples. In our study, we aimed to compare serum and plasma zinc test results for accurate and reliable zinc measurement in plain tubes with clot activator and gel and in heparin-free tubes, which specifically produced for trace element analysis. METHODS: Twenty-seven randomly selected patients were included in the study. Blood samples drawn simultaneously from patients were pipetted into tubes with clot activator and gel (SST) (SST II Advance, Vacutainer, Becton Dickinson and Company, USA) as well as into trace element tubes with sodium heparin (NH) (NH Trace Elements Sodium Heparin, Vacuette, Greiner Bio-One GmbH, Austria). After the centrifugation process, zinc levels in serum and plasma samples were analyzed by colorimetric method using an autoanalyzer. Bias between serum and plasma zinc levels was evaluated according to the allowable bias criterion based on biological variation and regression analysis performed. RESULTS: The mean and standard deviation of serum and plasma zinc levels were 49.0+-11.5 &#956;g/dL and 46.4+-12.0 &#956;g/dL, respectively, and a statistically significant difference was determined (p=0.012) in between. Besides, the bias between serum and plasma was 6.8%, which was above the allowable bias (3.3%) and considered as clinically significant. No systematic or random errors detected. DISCUSSION AND CONCLUSION: When selecting a blood collection tube for trace element analysis, the structural differences between tubes and the matrix effect should be considered carefully

Evaluation of D-dimer levels measured by different analytical methods in COVID-19 patients

Clinicians experience some challenges due to the lack of standardization of test, although D-dimer is a prognostic marker for COVID-19. We compared the clinical and analytical performances of D-dimer results obtained from different devices, kits and methods in patients with a diagnosis of COVID-19. Thirty-nine patients with a diagnosis of COVID-19 and 24 healthy individuals were included in the study. D-dimer levels were measured with Innovance D-DIMER kit (immunoturbidimetric method) on Sysmex CS-2500 and BCS XP and VIDAS D-Dimer Exclusion II kit (enzyme-linked fluorescence method) on mini VIDAS. The studies of precision, method comparison and clinic performance were performed. The variation coefficients in all systems were within the acceptable imprecision (7.8%). Bias%(12.5%) between BCS XP and Sysmex CS-2500 was lower than the acceptable Bias%(15.5%). Bias% values (19.2% and 33.3%, respectively) between Mini VIDAS with BCS XP and Sysmex CS-2500 were higher than the acceptable Bias%. The correlation coefficients among all systems were 0.89-0.98. For 500 ng/ml FEU, there was almost perfect agreement between BCS XP and Sysmex CS-2500, a moderate agreement between Mini VIDAS and BCS XP and Sysmex CS-2500. The cut-off values for distinguishing between individuals with and without COVID-19 were Mini VIDAS, Sysmex CS-2500 and BCS XP 529, 380 and 390 ng/ml FEU, respectively. The immunoturbidimetric method can be used as an alternative to the enzyme-linked fluorescent method because of satisfactory agreement at the different thresholds proposed for venous thromboembolism. However, it is recommended to follow up COVID-19 with the D-dimer results obtained by the same assay system