Ali Asci

Urinary Bisphenol A Levels in Girls with Idiopathic Central Precocious Puberty

Objective: Bisphenol A (BPA) is an industrial chemical, particularly used to harden plastics. BPA is thought to have negative health effects on both laboratory animals and humans. Consider ing the decline in age of onset of puberty noted in recent years, particularly among girls, the importance of BPA as an estrogenic endocrine disruptor has increased. In this study, we aimed to determine urinary BPA levels in girls with idiopathic central precocious puberty (ICPP). Methods: Non-obese girls newly diagnosed with ICPP (n=28, age 4-8 years) constituted the study group. The control group consisted of 25 healthy age-matched girls with no history of ICPP or any other endocrine disorder. Urinary BPA levels were measured by using high-performance liquid chromatography. Results: In the ICPP group, urinary BPA levels were significantly higher compared to the control group [median 8.34 (0.84-67.35) μg/g creatinine and 1.62 (0.3-25.79) μg/g creatinine, respectively (OR=8.68, 95% CI:2.03-32.72, p=0.001)]. There was no marked correlation between urinary BPA levels and body mass index in either group. In the ICPP group, no significant correlations were found between urinary BPA levels and serum luteinizing hormone, follicle-stimulating hormone and estradiol levels. Conclusions: To our knowledge, this is the first study evaluating the urinary BPA levels in Turkish girls with ICPP. Our results indicate that the estrogenic effects of BPA may be an etiologic factor in ICPP.

The evaluation of possible role of endocrine disruptors in central and peripheral precocious puberty

Abstract Exposure to environmental chemicals can affect genetic and epigenetic molecular pathways and may cause altered growth and development. Among those exposures, endocrine-disrupting chemicals (EDCs) are of particular concern as humans are abundantly exposed to these chemicals by various means in every period of life. Several well-known environmental chemicals, including phthalates and bisphenol A (BPA), are classified as EDCs. These EDCs are suggested to play roles in early onset of puberty in girls. The aim of this study is to determine plasma phthalate (di(2-ethylhexyl)phthalate [DEHP] and its main metabolite mono(2-ethylhexyl)phthalate [MEHP]) and urinary BPA levels in girls with idiopathic central precocious puberty (CPP) and peripheral precocious puberty (PPP). This study was performed on newly diagnosed idiopathic central precocious puberty (CPP) patients (n = 42) and peripheral precocious puberty (PPP) (n = 42) patients, who were admitted to Keçiören Training and Research Hospital, Clinic of Pediatric Endocrinology between August 2012 and –July 2013. Nonobese healthy girls (n = 50) were used as the control group. Urinary BPA levels were not statistically different in control, PPP and CPP groups (medians 10.91, 10.63 and 10.15 μg/g creatinine, respectively; p > 0.05). Plasma DEHP levels were significantly higher in PPP group when compared to control. Plasma MEHP levels were not significantly different in control and PPP groups (p > 0.05). However, in CPP group, both plasma DEHP and MEHP levels were significantly higher than control and PPP groups. This study showed that phthalates might play a role in the occurence of CPP in girls.

HPLC Method for Naproxen Determination in Human Plasma and Its Application to a Pharmacokinetic Study in Turkey

A simple high-performance liquid chromatography method has been developed for the determination of naproxen in human plasma. The method was validated on an Ace C18 column using ultraviolet detection. The mobile phase consisted of 20 mM phosphate buffer (pH 7) containing 0.1% trifluoroacetic acid-acetonitrile (65:35, v/v). The calibration curve was linear between the concentration ranges of 0.10 and 5.0 µg/mL. Intra-day and inter-day precision values for naproxen in plasma were less than 4.84, and accuracy (relative error) was better than 3.67%. The extraction recovery values of naproxen from human plasma were between 91.0 and 98.9%. The limits of detection and quantification of naproxen were 0.03 and 0.10 µg/mL, respectively. Also, this assay was applied to determine the pharmacokinetic parameters of naproxen in six healthy Turkish volunteers who had been given 220 mg of naproxen.

Evaluation of neopterin levels in patients undergoing hemodialysis

Neopterin is a diagnostic or a prognostic biomarker for several pathologies including renal diseases. However, the association between neopterin status and causative main reasons such as diabetes and hypertension for renal disease remains unclear. The aim of the study was to evaluate neopterin levels in diabetes and hypertension patients treated with/without hemodialysis. According to primary renal disorders, the patients undergoing hemodialysis were classified into 4 groups as diabetic nephropathy, hypertensive nephropathy, reflux nephropathy or interstitial nephritis, and others. The controls consisted of healthy subjects, hypertensive subjects, and diabetic individuals without any renal disorder. In the study, both urinary and serum neopterin levels were measured using high performance liquid chromatography and enzyme‐linked immunosorbant assay in patients undergoing regular hemodialysis therapy (n=71). The effects of the duration of hemodialysis and treatment of erythropoietin and/or iron on neopterin levels were also evaluated. Neopterin levels were found to be higher in hemodialysis patients than in the healthy controls (P<0.05). A significant difference in neopterin levels was also found between diabetic control patients and diabetic nephropathy patients (P<0.05). A similar significant difference was detected in neopterin levels between hypertensive patients with/without nephropathy (P<0.05). Neopterin may be an early critical marker for progression of nephropathy in diabetic and hypertensive patients in early stages.

Folate, neopterin and kynurenine pathway in patients with statin therapy

Abstract Statins, widely used antihyperlipidemic drugs, also have immunomodulatory properties independent from their lipid lowering effect. Even with slight modulations in the immune system, pteridine levels can display changes. The effect of statins on pteridines and related pathways has been demonstrated in a limited number of studies. The aim of the study was to evaluate the possible changes in neopterin and folate levels, and tryptophan (Trp) degradation in hyperlipidemic patients. Patients who were admitted to the cardiology clinic were randomly grouped if they were having statin treatment (n=69) or not (n=36). Serum Trp and kynurenine (Kyn), erythrocyte folate, and urinary neopterin levels were measured. It was found that urinary neopterin levels were significantly higher in patients on statin treatment (p<0.05) while levels of folate, Trp, Kyn, and Kyn-to-Trp ratios (Kyn/Trp) presented no significant changes (all, p>0.05). The correlation of the measured parameters was also evaluated and neopterin, folate and tryptophan degradation were found to be positively correlated. According to the results, neopterin levels, folate status and Trp degradation were altered in patients with statin treatment in comparison with the patients not receiving statin therapy. In order to point out the direct effect of statins on pteridines, further studies presenting both pre- and post-statin treatment of these parameters are needed.

Copper, zinc and iron levels in premature infants following red blood cell transfusion.

This study aimed to investigate effect of erythrocyte suspension (ES) transfusion on Cu, Zn, and Fe levels. It was conducted on 53 premature infants who were admitted to Hacettepe Hospital and received EST for first time. Blood samples were drawn before and 96h after ES transfusion to determine Cu, Zn, and Fe levels in plasma and/or erythrocytes. The mean plasma Cu levels were 99±3μg/dl and 113±3μg/dl; Zn levels were 105±2μg/dl and 115±23μg/dl; mean plasma Fe level was 58.1±19.4 and 75.2±25.4μg/dl and mean erythrocyte Fe level was 4182±2314μg/ml and 7009±5228μg/ml, before and after ES transfusion. The differences between before and after ES transfusion in Cu, Zn and Fe levels were significant. Correlation between plasma and erythrocyte Fe levels was significant both before and after ES transfusion. Though Fe overload is a major cause of morbidity/mortality after ES transfusion, alterations in trace elements should also be considered when transfusing blood to infants and children.

Evaluation of dihydropteridine reductase activities in patients with kidney failure

Abstract End-stage renal disease (ESRD) is the inability of the kidneys to remove waste products from the blood. The most important factors causing ESRD that require hemodialysis are diabetes and hypertension. There are limited numbers of studies to evaluate tetrahydrobiopterin pathway in these patients. The aim of the study was to evaluate tetrahydrobiopterin pathway by measuring its important components, biopterin to creatinine concentrations and dihydropteridine reductase activities in diabetes and hypertension patients treated with/without hemodialysis. The patients undergoing hemodialysis were classified as diabetic nephropathy (n=21), hypertensive nephropathy (n=20) and others (n=30), while the controls consisted of healthy subjects (n=21), diabetic subjects (n=23) and hypertensive subjects (n=22) without any renal disorder. It was found that urinary biopterin to creatinine concentrations significantly increased in kidney failure patients undergoing hemodialysis compared to the healthy control group (p<0.05). Additionally, there were significant differences in urinary biopterin to creatinine concentrations between diabetes or hypertension patients and their hypertensive or diabetic control counterparts (both p<0.05). Our results indicated an alteration in tetrahydrobiopterin pathway in ESRD, and in the presence of secondary pathologies such as diabetes and hypertension in the patients undergoing hemodialysis, more considerable changes are observed in the pathway.