Željko Romić

Antioxidants in patients with hyperthyroidism.

Abstract Hyperthyroidism is a hypermetabolic state accompanied by increased oxygen utilization, increased production of reactive oxygen species and consequentially measurable changes in antioxidative factors. Therefore, the activities of whole blood glutathione peroxidase (GPx) and erythrocyte superoxide dismutase (SOD), total antioxidant status (TAS) in serum and erythrocytes, and serum urate and transferrrin concentrations were determined in 70 women: 14 with newly diagnosed Graves disease (group A); 28 with hyperthyroidism on therapy with methimazole (group B, divided into two subgroups, B1 and B2) and 28 healthy women (group C). In comparison with control group C, GPx activity was significantly decreased in all patient groups (p<0.05), whereas SOD activity was significantly decreased in group A (p<0.01) and significantly increased in group B (p<0.01). In comparison with the control group, serum TAS activity was significantly decreased in group A, and erythrocyte TAS activity in all patient groups. Study results suggest that the impaired antioxidative factor balance leads to the development and presence of oxidative stress in women with hyperthyroidism. The severity of these alterations, considered contradictory by some authors, appears to depend on the use of therapy.

Endothelin-1, big endothelin-1, and nitric oxide in patients with chronic renal disease and hypertension

The complex pathogenesis of chronic renal disease (CRD) depends on endothelin (ET) axis (ETs and ET receptors) and nitric oxide (NO) because of their vasoactive effects and their role in general modulation of vascular homeostasis. Various renal cells synthesize ETs and NO that play a significant role in renal hemodynamics as well as in water and salt excretion via urine. ET‐1 is a strong vasoconstrictor. Besides its vasoactive effects, ET‐1 modulates mitosis and apoptosis in a cell type‐dependent manner, and may play an important role in CRD pathogenesis. The aims of this study were to emphasize the role and interactions of ET‐1, Big ET‐1, and NO in CRD. Concentrations of these vasoactive molecules were measured in plasma/serum and/or urine of 57 patients with diabetic nephropathy (subgroup 1), arterial hypertension (subgroup 2) or CRD with chronic renal insufficiency (subgroup 3), and in healthy control subjects (n=18). In comparison with control group, urine concentration of Big ET‐1 was significantly increased (13.13u2009pmol/L vs. 11.34u2009pmol/L; P<0.001) in CRD patients, whereas plasma and urine concentrations of ET‐1 did not differ significantly. NO concentrations were also significantly increased in CRD patients (serum, 72.55u2009µmol/L; P<0.001, and urine 141.74u2009µmol/L; P<0.05) as compared to control group. Study results indicated that Big ET‐1 and NO could be useful diagnostic parameters in CRD for their diagnostic sensitivity and diagnostic specificity (Big ET‐1 in urine: 56.1 and 88.9%, and NO in serum: 66.7 and 83.3%, respectively). In addition, Big ET‐1 may prove useful in the differential diagnosis of diabetic nephropathy (78.6% diagnostic sensitivity and 88.9% diagnostic specificity). J. Clin. Lab. Anal. 23:347–356, 2009.