Background
Indoleamine 2,3‐dioxygenase (IDO), which degrades tryptophan (Trp) to kynurenine (Kyn), has been demonstrated to contribute to modulation of allergic responses. However, the role of IDO in ...food allergy has not yet been elucidated.
Methods
Serum Trp and Kyn concentrations were analyzed by high‐pressure liquid chromatography. Expression of IDO gene was measured by real‐time PCR. The levels of interleukin (IL)‐4, IL‐10, and interferon (IFN)‐γ in cell culture supernatants were measured by ELISA.
Results
Kyn/Trp (IDO activity) was significantly lower in subjects with food allergy (n = 100) than in aged‐matched healthy controls (n = 112) (P = 0.004). Kyn/Trp was decreased from healthy through completely tolerant, partially tolerant, and reactive ones LN transformation (mean ± SEM) healthy: 3.9 ± 0.02 μM/mM; completely tolerant: 3.83 ± 0.04; partially tolerant: 3.8 ± 0.06; reactive: 3.7 ± 0.04 (P = 0.008). The frequency of genetic polymorphisms of IDO did not reveal a significant association with Trp, Kyn, and Kyn/Trp in healthy and food‐allergic cases. Culture of PBMC experiments yielded that IDO mRNA expression was not different between tolerant and reactive groups. IL‐4 synthesis when stimulated with casein increased significantly in subjects who are reactive and tolerant to foods (P = 0.042, P = 0.006, respectively). Increase in IL‐10 synthesis was observed only in children tolerant to milk, but not in reactive ones. IFN‐γ synthesis, when stimulated with IL‐2 and β‐lactoglobulin in cell culture, was significantly higher in subjects tolerant to milk than in the reactive ones (P = 0.005 and P = 0.029, respectively).
Conclusion
Our results imply the probability of involvement of IDO in development of tolerance process, and we presume that high IDO activity is associated with nonresponsiveness to food allergens despite allergen sensitization.
Neopterin production provides information about the extent of cellular immune activation. Measurement of neopterin levels may also provide predictive and prognostic information in patients with ...malignant thyroid diseases. In the present study, neopterin levels were investigated in patients with thyroid disorders (no.=68). Twenty-four patients had papillary thyroid cancers and the rest of them benign thyroid disorders. Results were compared with a healthy control group (no.=30). It was observed that there was a significant difference in neopterin levels between the control group and the thyroid disorders group (
p
<0.05). The mean neopterin levels in malignant and benign patients were also significantly different (
p
<0.05). Monitoring of urinary neopterin profile may be used in early diagnosis of papillary thyroid cancer. Neopterin seems to be a differential biomarker for malignant and benign thyroid disorders.
The aim of the present study was to evaluate whether aluminum exposure may cause alterations of cytochrome P4503A4 by measuring the urinary excretion of 6 beta-hydroxycortisol as biomarker. There is ...a positive correlation between urinary 6 beta-hydroxycortisol and aluminum excretion (p < 0.05). The correlations between occupational duration, smoking habits, and age were also evaluated. The increased excretion of the biomarker suggests that this element may induce formation of cytochrome P 450 in exposed individuals.
Occupational and environmental aluminum (Al) exposure cause serious health problems by interaction with biological systems. Al is one of the most documented metals because its cellular targets are ...unclear biochemical processes and membranes of organisms. The major aim of the present study was to investigate the alteration of serum and urine aluminum in occupational exposure and to observe whether the metal exposure could cause any changes in pteridine-pathway-related critical compounds such as urinary neopterin and biopterin and blood dihydropteridine reductase (DHPR). In this study, determination of the metal concentrations was carried out in Al-exposed workers (n=23) and healthy volunteers (n=18) by using atomic absorption spectrometer. DHPR enzyme activity and levels of neopterin and biopterin were detected by spectrophotometric and high-performance liquid chromatographic methods, respectively. It was found that occupational exposure to the metal led to a statistically significant increase in serum Al levels compared to the controls (p<0.05). At the same time, urinary neopterin and biopterin concentrations of the exposed group were higher than nonexposed subjects (both p<0.05). The correlations among Al levels and DHPR activity, magnesium concentration in serum and urine, working years, smoking status, and age were evaluated.
Nitrites are ubiquitous environmental contaminants present in drinking water and foods. Nitrosamines can be formed endogenously from nitrate and nitrite and secondary amines or may be present in ...food, tobacco smoke, and drinking water. The major goal of this work was to evaluate the cytotoxic, reactive oxygen species (ROS)-producing and genotoxic effects of nitrite and nitrosamines and the possible protection by ascorbic acid in HepG2 cells. It was found that nitrite, N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), and N-nitrosomorpholine (NMOR) decreased cell viability, increased intracellular ROS production, and caused genotoxicity. Compared to untreated cells as determined by alkaline Comet assay, nitrite, NDMA, NDEA, and NMOR raised the tail intensity up to 1.18-, 3.79-, 4.24-, and 4.16-fold, respectively. Ascorbic acid (AA, 10 μM) increased cell viability and reduced ROS production significantly (p < 0.05). Additionally, AA treatment decreased the tail intensity caused by nitrite, NDMA, NDEA, and NMOR to 33.74%, 58.6%, 44.32%, and 43.97%, respectively. It can be concluded that ascorbic acid was able to reduce both tail intensity and tail moment in all of the nitrosamine treatments, particularly in NDMA. AA protected HepG2 cells against genotoxic effects caused by nitrosamines. This protection might be through different mechanisms, some of which are not still understood in depth. The future interest will be to understand which pathways are influenced by antioxidants, particularly by AA, and the outcomes of this prevention in other cell line types.
Nitrites and nitrates possess a unique position in human toxicology. They are both ubiquitous in the environment and can be formed from nitrogenous compounds. Water, vegetables and meat are important ...sources of nitrite exposure. Nitrites have several detrimental effects on health. The primary health concern regarding nitrate and nitrite exposure is the formation of methemoglobinemia. Baby food and infant formulas can be important sources of nitrite and infants younger than six months are the most susceptible population. Furthermore, nitrites react with primary, secondary, or tertiary amines in an acid medium and form nitrosamines many of which are known to cause cancer. Health care providers, governments and health authorities should be aware of the routes of nitrite exposure and must have knowledge to assess the hazards. This review will focus on the detrimental effects of nitrite exposure, the possible outcomes and standards put by regulatory authorities to prevent high nitrite exposure especially for susceptible populations.
