Surucu Kara, Ilknur; Mertoglu, Cuma; Siranli, Gülsah; Arslan, Yusuf Kemal; Gok, Gamze; Erel, Ozcan

Aim: The aim of the study is to examine the relationship between obesity, Vitamin-D deficiency, and protein oxidation. Methods: Thiol-disulfide homeostasis, Vitamin-D, ischemia modified albumin, insulin, and lipid levels were compared among obese, pre-obese and normal-weight healthy children. Results: A total of 136 children (69 boys and 67 girls) were included in the study. The vitamin-D levels of obese children were lower than those of pre-obese and normal weight (p < 0.05). In the normal weight group, total thiol and native thiol were lower in the pubertal period than in adolescence; were higher in those with sufficient Vitamin-D level than those with insufficient and deficient Vitamin-D (p < 0.05). Vitamin-D level was lower in pre-obese girls than boys (p < 0.05). Those with high triglycerides had high disulfide/total thiol, disulfide, and disulfide/native thiol and low native thiol/total thiol (p < 0.05). Conclusion: Thiol-disulfide homeostasis is negatively affected by low vitamin D levels, pubertal period and high triglyceride levels.

Topal, Ismail; Mertoglu, Cuma; Sürücü Kara, Ilknur; Gok, Gamze; Erel, Ozcan

Aim: The aim is to compare the markers of oxidative stress in iron deficient children to that of non-anemic children. Method: Serum thiol-disulfide level, ferroxidase activity and ischemia-modified albumin (IMA) levels were compared between iron deficiency anemia (IDA) and non-anemic children. Results: A total of 117 children, 66 with IDA and 51 non-anemic children were included in the study. Disulfide, disulfide/native thiol, and disulfide/total thiol levels were significantly higher in the IDA group (p: 0.001). Serum ferroxidase levels were significantly lower in the IDA group (p: 0.04); but there was no significant difference between the two groups regarding serum IMA levels (p: 0.42). There was a weak negative correlation between disulfide and serum hemoglobin (p: 0.004), iron (p: 0.041), and ferritin (p: 0.023) levels while there was a weak positive correlation between ferroxidase activity and these parameters. Conclusion: There is an increased protein oxidation in children with IDA compared with non-anemic controls.

Topal, Ismail; Mertoglu, Cuma; Surucu Kara, Ilknur; Siranli, Gulsah; Gok, Gamze; Erel, Özcan

Aim: Hyperbilirubinemia causes oxidative stress. Method: We evaluated three oxidative stress markers in hyperbilirubinemic neonates (native/total thiol levels, serum ferroxidase activity and ischemia modified albumin (IMA), comparing these levels to levels in a control group to determine which indicators were the most sensitive. Results: Serum from 124 term infants (67 with pathologic jaundice and 57 controls) were evaluated. Native/total thiol ratio was significantly lower (p:0.021) while disulfide levels were significantly higher (p:0.001) in the jaundiced group. There was no significant difference in ferroxidase (p:0.603) or IMA (p:0.251) levels. Conclusion: Altered thiol/disulfide homeostasis in the favor of disulfide indicates augmented oxidative stress in jaundiced term infants. The lack of alteration in ferroxidase or IMA levels suggests these latter alterations take more time or more severe oxidative stress to become altered or are not as sensitive as the thiol/disulfide ratio to detect oxidative stress states.

Mertoğlu, Cuma; Gunay, Murat; Siranli, Gulsah; Kulhan, Mehmet; Gok, Gamze; Erel, Özcan

Aim: A 50 g glucose challenge test (GCT) is recommended for screening all pregnant women for gestational diabetes mellitus. In this study, the effect of GCT on the thiol/disulfide balance was investigated. Methods: One-hundred women that underwent a 50 g GCT at 24–28 weeks of gestation (63 positive and 37 negative results) were evaluated in terms of thiol/disulfide in serum samples at test hours 0 and 1. Results: Compared to the baseline values (hour 0), after the glucose load (hour 1), the thiol and native thiol/total thiol (p < 0.0001) of the GCT-positive women were reduced whereas the values of glucose, disulfide, disulfide/native thiol, disulfide/total thiol (p < 0.0001) and total thiol increased (p = 0.018). Conclusion: In GCT-positive pregnant individuals, the glucose load increases oxidative stress by changing the thiol/disulfide homeostasis. Such an effect is not observed in healthy pregnancies.