Aysenur Yegin

Increased levels of total oxidant status and decreased activity of arylesterase in migraineurs.

OBJECTIVES There is strong evidence associating migraine with a variety of comorbid disorders, including cardiovascular disease and stroke, in which oxidative stress seems to be an important underlying mechanism. The aim of the study was to investigate in migraineurs the body oxidant/antioxidant balance and paraoxonase enzyme activities as a measure of HDL functionality. DESIGN AND METHODS Oxidative stress index, total oxidant status and antioxidant status were examined in addition to the paraoxonase and arylesterase enzyme activities in sixty-two migraineurs and fifty healthy control subjects. RESULTS Serum arylesterase activities were significantly lower in migraineurs (p=0.0065), whereas total oxidant status was higher in patients compared to the controls (p=0.0035). CONCLUSIONS This preliminary study showed that oxidative/antioxidative balance shifted towards the oxidative status in migraine. Moreover, the results also suggested that decreased arylesterase activities might be associated with HDL-related disfunction.

The effect of bilirubin on lipid peroxidation and antioxidant enzymes in cumene hydroperoxide-treated erythrocytes

Recently, it has been suggested that bilirubin may act as a potent biological chain-breaking antioxidant. To observe the effects of free bilirubin on antioxidant reactions in cumene hydroperoxide-treated erythrocytes (15 g hemoglobin/dl), we added bilirubin at four different concentrations (0.5, 1, 5, and 10 mg/dl). We measured the thiobarbituric acid-reactive substance and reduced glutathione levels, and some antioxidant enzyme activities, namely superoxide dismutase, catalase, and glucose-6-phosphate dehydrogenase. Thiobarbituric acid-reactive substance and chemiluminescent signals decreased during the incubation. Superoxide dismutase activities also decreased but not as much as in the control group. Glucose-6-phosphate dehydrogenase activities and reduced glutathione levels increased, but catalase activities remained the same as the control group. Our results suggest that bilirubin — in the concentrations we have used — partially prevented the oxidant effects of cumene hydroperoxide.

Impaired oxidative balance and association of blood glucose, insulin and HOMA-IR index in migraine

INTRODUCTION The nature of the relationship between glucose metabolism and occurrence of migraine has not been elucidated precisely. This study investigated the status of oxidative/antioxidative balance and its relationship with the glucose metabolism in migraineurs to get new points of view for the underlying oxidative mechanisms. MATERIALS AND METHODS Sixty migraineurs and 46 control subjects were included in the study. Oxidative stress index, total oxidant and antioxidant status of both groups were examined in addition to the insulin and HOMA-IR index levels. RESULTS HOMA-IR index was significantly enhanced in migraineurs (P = 0.038); similarly oxidative stress index and total oxidant status were higher in patients compared to the controls (P < 0.001 for both). CONCLUSION This preliminary study shows that oxidative/antioxidative balance shifts towards the oxidative status in migraine. Higher total oxidant status and elevated HOMA-IR index might play a role in the potential early pathogenesis for migraine.

Serum Glycated Lipoproteins in Type II Diabetic Patients with and without Complications

The extent of lipoprotein glycation was assessed in 82 patients diagnosed as diabetes mellitus type II. Glycated lipoprotein levels in serum were determined by agarose gel film electrophoresis in 48 non-diabetic control subjects, 56 diabetics with complications and 26 diabetics with no complications. All glycated lipoproteins were higher in the patients when the diabetics were compared to the control group, but glycated very low-density lipoprotein (VLDL) was the only glycated lipoprotein fraction that was observed to be higher in the diabetic patients with complications compared to the patients without complications (P < 0·01). Triglycerides and VLDL-cholesterol were also increased in the diabetics, but there was no significant difference in these variables when the patients without complications were compared to the control subjects. There was no difference in total cholesterol and low-density lipoprotein (LDL)-cholesterol levels of the diabetic patients compared to the controls.

Inhibition of Human Erythrocyte (Na+-K+)ATPase by Organic Hydroperoxides and Protection by Ascorbic Acid and Butylated Hydroxytoluene

1. The in vitro effects of cumene hydroperoxide and t-butyl hydroperoxide on intact human erythrocyte membrane (Na(+)-K+)ATPase activities have been studied. 2. (Na(+)-K+)ATPase activities on erythrocyte membranes decreased in agreement with the results of chemiluminescence experiments. 3. Our results demonstrated that the organic hydroperoxides inhibit the activity of (Na(+)-K+) ATPase enzyme and that the antioxidants used prevent this inhibition.

Pre-Test and Post-Test Applications to Shape the Education of Phlebotomists in A Quality Management Program: An Experience in A Training Hospital

Summary Background: After the introduction of modern laboratory instruments and information systems, preanalytic phase is the new field of battle. Errors in preanalytical phase account for approximately half of total errors in clinical laboratory. The objective of this study was to share an experience of an education program that was believed to be successful in decreasing the number of rejected samples received from the Emergency Department (ED). Methods: An education program about laboratory procedures, quality requirements in the laboratory, patient and health-care worker safety was planned by the quality team to be performed on 36 people who were responsible for sample collection in the ED. A questionary which included 11 questions about the preanalytic phase was applied to all the attendees before and after training. The number of rejected samples per million was discovered with right proportion account over the number of accepted and rejected samples to laboratory after and before the training period. Results: Most of the attendees were nurses (n: 22/55%), with over 12 years of experience in general and 2-4 years experience in the ED. Knowledge level of the attendees was calculated before training as 58.9% and after training as 91.8%. While the total rate of sample rejection before training was 2.35% (sigma value 3.37-3.50), the rate after training was 1.56% (sigma value 3.62-3.75). Conclusions: Increasing the knowledge of staff has a direct positive impact on the preanalytic phase. The application of a pre-test was observed to be a feasible tool to shape group specific education programs.

Increased resistance to oxidative stress in normal and glucose-6-phosphate dehydrogenase-deficient hemolysates in the presence of enzyme substrates

Erythrocytes and hemolysates from 10 normal and 10 glucose-6-phosphate dehydrogenase-deficient individuals were incubated with cumene hydroperoxide, and free radical-induced lipid peroxidation was monitored by chemiluminescence. Chemiluminescence intensities in erythrocytes of normal and deficient subjects were similar in the presence or absence of glucose-6-phosphate dehydrogenase substrates. Hemolysates of normal and deficient subjects also showed similar chemiluminescence in the absence of substrates. However, with the addition of substrates to the incubation medium, deficient hemolysates reached maximum chemiluminescence intensity within a shorter period, and maximum values were higher than in normal hemolysates. We believe this offers a new means of detection of glucose-6-phosphate dehydrogenase-deficient patients.

A model for managing and monitoring the quality of glucometers used in a high-volume clinical setting

Introduction The aim of this study is to present a model for assuring the quality of a large number of glucometers being used in a high-volume hospital clinical setting. Materials and methods Internal quality-control samples and blood samples from two patients were used to determine the accuracy of 83 glucometers used at our hospital. On each glucometer three levels of control were used for glucose concentrations determination. In addition, the difference between the results from patient samples obtained with the glucometers and the hexokinase reference method were compared. The differences were assessed based on the International Organization for Standardization (ISO 15197) standards. Results The glucose concentrations were as follows: 2.51 ± 0.34 mmol/L for the hypo-control samples; 5.12 ± 0.32 mmol/L for the low-control samples; and 16.11 ± 1.03 mmol/L for high-control samples. All results were within the expected ranges. For Patient I, the result with the first group of 52 glucometers was 11.56 ± 0.5 mmol/L, while the result for Patient II with the second group of 31 glucometers was 10.52 ± 0.62 mmol/L. All data points of the study complied with the requirements of the Clarke error grid. Conclusion All quality-control and comparison assay results were appropriate for evaluating glucometers used in a high-volume hospital setting. The method used in this study can be suggested as a model for laboratory managers, especially in similar high-volume hospitals.