In vitro study of the binding between chlorpyrfos and sex hormones using headspace solid-phase microextraction combined with high-performance liquid chromatography: A new aspect of pesticides and breast cancer risk

Endocrine-disrupting chemicals are compounds that alter the normal functioning of the endocrine system. Organophosphorus insecticides, as chlorpyrifos (CPS), receive an increasing consideration as potential endocrine disrupters. Physiological estrogens, including estrone (E1), 17β-estradiol (E2), and diethylstilbestrol (DES) fluctuate with life stage, suggesting specific roles for them in biological and disease processes. There has been great interest in whether certain organophosphorus pesticides can affect the risk of breast cancer. An understanding of the interaction processes is the key to describe the fate of CPS in biological media. The objectives of this study were to evaluate total, bound, and freely dissolved amount of CPS in the presence of three estrogenic sex hormones (ESHs). In vitro experiments were conducted utilizing a headspace solid phase microextraction (HS-SPME) combined with high-performance liquid chromatography (HPLC) method. The obtained Scatchard plot based on the proposed SPME-HPLC method was employed to determine CPS-ESHs binding constant and the number of binding sites as well as binding percentage of each hormone to CPS. The number of binding sites per studied hormone molecule was 1.10, 1, and 0.81 for E1, E2, and DES, respectively. The obtained results confirmed that CPS bound to one class of binding sites on sex hormones.

Serum level of matrix metalloproteinase-9 in patients with salivary gland tumor

STATEMENT OF THE PROBLEM

Matrix metalloproteinases (MMPs) have been implicated in the pathogenesis of certain diseases and cancers via tissue destruction and can be secreted into the blood stream. MMP9 expression in the salivary gland tissue was evaluated but their serum level in the salivary gland tumors was not studied.

PURPOSE

The aim of our study was to determine the concentration of serum MMP-9 in healthy participants and in patients with salivary gland tumor.

MATERIALS AND METHOD

Using an ELISA kit, the circulating levels of MMP-9 in sera from 58 patients with salivary gland tumor (31 pleomorphic adenoma, 17 adenoid cystic carcinoma and 10 mucoepidermoid carcinoma) and 30 healthy controls was assessed.

RESULTS

The serum MMP9 level in patients with salivary gland tumors (380.0±301.3 pg/ml) also patients with benign tumors (354.3±218.7 pg/ml) (354.3±218.7 pg/ml) were significantly lower than that in the healthy group (727.4±624.6 pg/ml) (Respectively p= 0.02 and p= 0.01). Mean serum MMP9 concentration in malignant tumors was (402.3±441.8pg/ml) higher than benign tumors (354.3±218.7 pg/ml) but the difference was not significant (p= 0.9).

CONCLUSION

Our results showed that serum level of MMP9 decreased in patients with salivary gland tumors which suggest that MMP9 may not have a potential role in development and pathogenesis of salivary gland tumor.

Application of experimental design for extraction of BHA and BHT from edible vegetable oil and their determination using HPLC

The optimal conditions of liquid–liquid extraction of two synthetic phenolic antioxidants, BHA and BHT were investigated in five Iranian edible vegetable oil samples using the central composite design. Stepwise multiple linear regression method was used for construction of different models based on the experimental data. Optimum conditions for BHA and BHT were achieved using 3 ml of ethanolic solution containing (0.25% v/v) of glacial acetic acid, three extractions and a mixing time of 10 minutes. Analytes were separated using HPLC with a C 18 column using methanol:water:glacial acetic acid (75:24:1, v/v/v) as the mobile phase. The limit of detections, linear ranges and relative standard deviation ( n = 7 ) were 0.04 μg/g−1 , 0.5– 200 μg/g−1 and 2.6% for BHA and 0.30 μg/g−1 , 1.0– 200 μg/g−1 and 4.20% for BHT, ( r 2 > 0 . 9 9 ), respectively. Amounts of BHA and BHT in analyzed oil samples were in the ranges of 29.8– 54.5 μg/g−1 and 0.0– 6.8 μg/g−1 respectively.

Determination of aliphatic amines using fluorescence intensity of 4-methyl umbelliferone

Effect of aliphatic amines and their concentration on fluorescence intensity of 4-methyl umbelliferone (4-MU) one of coumarin derivative were investigated. This compound has blue light emission under UV lamp in methanolic solution. Spectral investigation of 4-MU solution containing amine compounds showed lower intensity at 350-410 nm (quenching region) and higher intensity at 430-500 nm (enhancing region) as compared to pure methanolic solution of 4-MU. Fluorescence intensity at isoemitting point was independent from concentration of amines. The variation of fluorescence intensity could be used for determination of aliphatic amines in both quenching and enhancing region. Linear ranges for determination of amines in the quenching region were obtained from Stern-Volmer diagram of 4-MU. Determination of amines at fluorescence enhancing region using inverse fluorescence intensity against inverse amine concentration (bireciprocal plot) were investigated and related equations was also proposed.