Murat Büyükşekerci

Thiol/disulfide homeostasis in asphalt workers

ABSTRACT The aim of this study was to investigate thiol/disulfide homeostasis in asphalt workers who are exposed to polycyclic aromatic hydrocarbons occupationally. The study was carried out in 34 nonsmoker asphalt workers. Additionally, 35 healthy nonsmoker volunteers were recruited as control group. Thiol and disulfide concentrations were determined using the novel automated measurement method. Levels of urinary 1-OH-pyrene were analyzed by liquid chromatography. Disulfide/thiol ratio was significantly higher in exposed group (p = .034). Also, a positive correlation was detected between disulfide/thiol ratio and 1-OH-pyrene values (r = .249, p = .036). Thiol/disulfide homeostasis was found to be disturbed in asphalt workers. The novel test used in this study may be useful for evaluating the oxidative status in polycyclic aromatic hydrocarbon (PAH) exposure.

Dynamic disulfide/thiol homeostasis in lead exposure denoted by a novel method

Lead is a toxic heavy metal, and prevention of human exposure to lead has not been accomplished yet. The toxicity of lead is continually being investigated, and the molecular mechanisms of its toxicity are still being revealed. In this study, we used a novel method to examine thiol (SH)/disulfide homeostasis in workers who were occupationally exposed to lead. A total of 80 such workers and 70 control subjects were evaluated, and their native and total SH values were measured in serum using a novel method; their blood lead levels were also assessed. The novel method used for SH measurements was based on the principle of measuring native SH, after which disulfide bonds were reduced and total SHs were measured. These measurements allowed us to calculate disulfide amounts, disulfide/total SH percent ratios, disulfide/native SH percent ratios, and native SH /total SH percent ratios. We found that disulfide levels were significantly higher in workers who were exposed to lead (21.08(11.1–53.6) vs. 17.9(1.7–25), p < 0.001). Additionally, the disulfide/native SH and disulfide/total SH percent ratios were higher in exposed workers, while the native SH/total SH percent ratios were higher in the control subjects. Furthermore, the lead and disulfide levels showed a positive correlation, with p < 0.001 and a correlation coefficient of 0.378. Finally, the novel method used in this study successfully showed a switch from SH to disulfide after lead exposure, and the method is fully automated, easy, cheap, reliable, and reproducible. Use of this method in future cases may provide valuable insights into the management of lead exposure.

Evaluation of Dynamic Disulphide/Thiol Homeostasis in Silica Exposed Workers

Background: Oxidative stress is implicated as one of the main molecular mechanism underlying silicosis. Aims: In this study, our aim was to asses the redox status in occupationally silica-exposed workers, by evaluating the dynamic thiol-disulphide homeostasis. Study Design: Case-control study. Methods: Thirty-six male workers occupationally exposed to silica particles and 30 healthy volunteers, working as office workers were included to the study. Posteroanterior chest radiographs and pulmonary function tests of both groups were evaluated. Also serum thiol disulphide levels were measured using the spectrophotometric method described by Erel and Neşelioğlu. Results: Among the 36 workers that underwent pulmonary function tests 6 (17%) had obstructive, 7 (19%) had restrictive, 6 (17%) had obstructive and restrictive signs whereas 17 (47%) had no signs. The mean PFTs results of silica-exposed workers were significantly lower than control subjects. The serum disulphide levels of silica-exposed workers were significantly higher than control subjects (23.84±5.89 μmol/L and 21.18±3.44 μmol/L, respectively p=0.02). Conclusion: The serum disulphide levels, a biomarker of oxidative stress, are found to be higher in silica-exposed workers.

Occupational exposure to asphalt fume can cause oxidative DNA damage among road paving workers

OBJECTIVES We designed the present study to determine the effect of occupational exposure to asphalt fumes on oxidative status and DNA damage in road paving workers. METHODS Sixty road paving workers exposed to asphalt fumes and forty non-exposed control subjects were recruited. Occupational exposure to PAHs was assessed by urinary 1-hydroxypyrene (1-OHP) excretion. Serum thiol disulfide homeostasis (TDH), total oxidant status (TOS) and total antioxidant status (TAS) and urinary 8-hydro-deoxyguanosine (8-OH-dG) level were evaluated by automated colourimetric method. RESULTS The urinary concentrations of 1-OHP and 8-OH-dG were significantly higher in the exposed group than in the control group (P < 0.001). Disulfide/thiol ratio, TOS, and TAS were also significantly higher for the asphalt workers. A positive correlation existed between urinary 1-OHP and 8-OH-dG, TOS and TAS. CONCLUSION Study results indicate that exposure to PAHs induces oxidative stress and causes genotoxic effects in asphalt workers.

Investigation of the hair and urine samples’ utility for screening lead poisoning

Objective: The aim of this study is to compare whole blood, 24 hour urine and hair lead levels which were measured concurrently, and evaluate the utility of hair and urine samples for screening of lead exposure. Methods: The data of 436 workers who referred to Ankara Occupational Diseases Hospital between 2010 and 2014 for periodic examination were evaluated. People who examined whole blood, 24 hour urine and hair lead levels concurrently were included in this study. People were evaluated according to two different whole blood exposure levels (10 μg/dL and 30 μg/dL). Results: 24 hour urine and hair lead levels of the groups classified according to whole blood exposure limits were different from each other and statistically significant (p<0,001). Whole blood lead level showed a positive correlation with 24h urine lead level and hair lead level (r=0,552; p<0,001, r=0,566; p<0,001, respectively). 24 hour urine specimens showed 53% sensitivity, 100% specificity, 0% false positivity and 49% false negativity, while the hair displayed 95% sensitivity, 64% specificity, 16% false positivity and 13% false negativity according to the 10 μg/dL limit value. Moreover, ÖZET Amaç: Bu çalışmanın amacı, eş zamanlı olarak bakılan tam kan, 24 saatlik idrar ve saç kurşun düzeylerinin birbiri ile karşılaştırılması ve kurşun maruziyetinin taranmasında saç ve idrar numunelerinin kullanılabilirliğinin araştırılmasıdır. Yöntemler: Ankara Meslek Hastalıkları Hastanesi’ne 2010-2014 yılları arasında periyodik muayene amacıyla başvuran 436 işçiye ait veriler değerlendirildi. Tam kan, 24 saatlik idrar ve saç kurşun düzeyleri eş zamanlı olarak bakılmış kişiler çalışmaya dâhil edildi. Kişiler iki farklı tam kan maruziyet düzeyine (10 μg/dL ve 30 μg/dL) göre değerlendirildi. Bulgular: Tam kan maruziyet sınırlarına göre sınıflandırılan grupların 24 saatlik idrar ve saç kurşun düzeyi birbirinden farklı ve istatistiksel olarak anlamlı idi (p<0,001). Tam kan kurşun düzeyi 24 saatlik idrar kurşun düzeyi ve saç kurşun düzeyi ile pozitif bir korelasyon gösteriyordu (sırasıyla; r=0,552; p<0,001, r=0,566; p<0,001). 10 μg/dL sınır değerine göre saç %95 duyarlılık, %64 özgüllük, %16 yalancı pozitiflik, %13 yalancı negatiflik gösterirken 24 saatlik idrar örnekleri %53 duyarlılık, %100 özgüllük, %0 yalancı pozitiflik ve %49 yalancı negatiflik gösteriyordu. 30 μg/dL sınır 1 Yıldırım Beyazıt Üniversitesi, Biyokimya Ana Bilim Dalı, Ankara 2 Ankara Meslek Hastalıkları Hastanesi, Farmakoloji Bölümü, Ankara 2 Aydın Halk Sağlığı Laboratuvarı, Biyokimya Bölümü, Ankara 2 Ümraniye Eğitim ve Araştırma Hastanesi, Biyokimya Bölümü, İstanbul 2 Ankara Meslek Hastalıkları Hastanesi, Toksikoloji Bölümü, Ankara Geliş Tarihi / Received : Kabul Tarihi / Accepted : İletişim / Corresponding Author : Ceylan BAL Yıldırım Beyazıt Üniversitesi Tıp Fakültesi, Bilkent Yerleşkesi, Çankaya, Ankara 06280 Ankara Türkiye Tel : +90 505 745 84 38 E-posta / E-mail : ceylandemirbal@gmail.com 02.03.2016 27.06.2016 DOI ID : 10.5505/TurkHijyen.2016.88896 Türk Hijyen ve Deneysel Biyoloji Dergisi Bal c, Büyülşekerci M, Ercan M, Torun-Güngör O, Tutkun E, Yılmaz FM. Kurşun maruziyetinin taranmasında saç ve idrar numunelerinin kullanılabilirliğinin araştırılması. Turk Hij Den Biyol Derg, 2016; 73(4): 303-310 Makale Dili “Türkçe”/Article Language “Turkish”