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Aflatoxin is a liver carcinogen, and rapid, inexpensive methods to detect its urinary biomarkers are needed. We used a commercial enzyme-linked immuno-sorbent assay (ELISA) for aflatoxin M1 in urine (Helica Biosystems) to test 52 Haitian samples. Using this ELISA, we detected traces above the limit of detection (0.2 ng/ml urine) but below the limit of quantitation (0.4 ng/ml) in 14 samples. Liquid chromatography of all 52 Haitian urine samples revealed that only 11 had quantifiable AFM1 (mean: 29.5 pg/ml, standard error: 10.8, range: 2.94–96.5 pg/ml). The Helica ELISA may have detected forms of aflatoxin other than AFM1 in the Haitian samples, or matrix enhancement may have affected results at low AFM1 concentrations. This ELISA may serve as an initial, qualitative indicator of aflatoxin exposure for epidemiological purposes. But this method’s utility as a precise and specific indicator of AFM1 concentrations will require additional refinement and validation. [ABSTRACT FROM PUBLISHER]

The broad topic of biomarker research has an often-overlooked component: the documentation and interpretation of the surrounding chemical environment and other meta-data, especially from visualization, analytical and statistical perspectives. A second concern is how the environment interacts with human systems biology, what the variability is in 'normal' subjects, and how such biological observations might be reconstructed to infer external stressors. In this article, we report on recent research presentations from a symposium at the 248th American Chemical Society meeting held in San Francisco, 10-14 August 2014, that focused on providing some insight into these important issues. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the representativeness of single measurement of urinary soy-isoflavone concentrations for the assessment of long-term intake levels. Methods: Five urine samples taken from 14 Japanese female subjects over 2-3 months were measured for daidzein and equol by gas chromatography-mass spectrometry (GC-MS). Results: Geometric mean daidzein and equol concentrations of 14 subjects were 582 and 2.66 μg/g creatinine, respectively. Intra-class correlation coefficients for daidzein and equol were 0.355 (95% CI: 0.130-0.649) and 0.741 (0.551-0.891), respectively. Conclusion: Single measurement of urinary equol is effective for the assessment of long-term equol status of Japanese subject while that of daidzein is not. [ABSTRACT FROM AUTHOR]

Background: There was few study concentrated on the correlation between the evaluated tumor markers and lymph node metastasis. In this study, we aimed to evaluate the correlation between the CA724, CA242, CAI 99, CEA and the lymph node metastasis of gastric cancer and assess the prognostic value of them in different N stage patients. Methods: We analyzed the correlation between serum level of CA724, CA242, CA199, CEA and lymph node metastasis in 1501 gastric cancer patients. Results: Lymph node metastasis of gastric cancer was related with tumor location, Bormann type, tumor size, histological type, depth of invasion and TNM stage (p<0.05). The values of CA724, CA242, CAI 99 and CEA were positively correlated with the metastatic lymph node counts and the N stage (p <0.05). The later the N stage was, the levels of CA724, CA242 and CA199 were higher. The later the N stage was, the positive rates of tumor markers were higher (p<0.05). In comparing with single tumor markers, the positive rates of tumor markers combination were higher. The combination of CA724 + CA242 + CA199 + CEA had highest positive rate. The higher CEA level related to N1 stage patients while higher CAI 99 was related with poor prognosis for N1 stage patients. For NO and N2 stage patients, evaluation of CA724 indicated poorer prognosis. For N1 and N2 stage gastric patients, the patients with increased CA242 inclined to have shorter survival time. Conclusions: The tumor makers CA724, CA242, CAI 99 and CEA were evaluated significantly in the gastric patients with later N stage. The combination of these four tumor markers maybe prefer diagnostic index of gastric cancer and its lymph node metastasis. These tumor markers can be a possible indicator of poorer prognosis in different N stage patients. [ABSTRACT FROM AUTHOR]

Toluene diisocyanates (2,4-TDI and 2,6-TDI) are important intermediates in the chemical industry. Among the main damages after low levels of TDI exposure are lung sensitization and asthma. It is therefore necessary to have sensitive and specific methods to monitor isocyanate exposure of workers. Urinary metabolites or protein adducts have been used as biomarkers in workers exposed to TDI. However, with these methods it was not possible to determine if the biomarkers result from exposure to TDI or to the corresponding toluene diamines (TDA). This work presents a new procedure for the determination of isocyanate-specific albumin adducts. Isotope dilution mass spectrometry was used to measure the adducts in albumin present in workers exposed to TDI. 2,4-TDI and 2,6-TDI formed adducts with lysine: Nεϵ-[({{3-amino-4-methylphenyl}}amino)carbonyl]-lysine, Nεϵ-[({{5-amino-2-methylphenyl}}amino)carbonyl]-lysine, and Nεϵ- [({{3-amino-2-methylphenyl}}amino)carbonyl]-lysine. In future studies, this new method can be applied to measure TDI-exposures in workers. [ABSTRACT FROM AUTHOR]

Context: Benzene is a ubiquitous pollutant; smoking habit, genetic polymorphisms, and analytical difficulties impact the identification of the best biomarker. Objective: To apply a systematic quantitative approach to evaluate urinary benzene (BEN-U) and S-phenylmercapturic acid (SPMA) as biomarkers of low benzene exposures. Methods: Seventy-one blue collar refinery workers, 97 white collar refinery workers and 108 general population subjects were included. Intrinsic characteristics, sampling and analytical issues were compared. Results: BEN-U and SPMA were detected in 99% and 78% of samples, which correlated with benzene exposure ( r == 0.456 and r == 0.636, respectively) and with urinary cotinine ( r == 0.630 and r == 0.570, respectively). Intrinsic characteristics were similar for the two biomarkers: specificity (0.64 and 0.69 for BEN-U and SPMA), sensitivity (0.74 and 0.83), as well as intra- and inter-individual variability (150% and >14 for both). Conclusion: BEN-U and SPMA show similar intrinsic characteristics; analytical issues in detecting SPMA suggest that BEN-U is more convenient for investigating low exposure levels. [ABSTRACT FROM AUTHOR]

The aromatic amine 4-aminobiphenyl (4-ABP) is present in tobacco smoke. In humans, it is also a known bladder carcinogen. We describe here a method for the quantification of total 4-ABP in urine using capillary gas chromatography/tandem mass spectrometry, with an effective detection limit in urine samples of approximately 0.87 pg/mL. We also examined the efficiency of chemical or enzymatic hydrolysis of urinary aromatic amine metabolites. Although we found acidic or basic hydrolysis effective, we found enzymatic hydrolysis (ββ-glucuronidase with either Escherichia coli or Helix pomatia) ineffective. As part of this work, we also confirm the presence of N-acetyl-4-ABP and 4-ABP glucuronide in human urine samples from smokers. These metabolites have been reported in animal studies, but previously they have not been identified in human samples. These metabolites, however, were found to be unstable and thus infeasible for biomonitoring. The final validated urinary total 4-ABP assay was applied to the analysis of samples from smokers and nonsmokers, whose status was confirmed from cotinine EIA measurements. Among 41 confirmed nonsmokers, the geometric mean (95% CI) of 4-ABP concentration was 1.64 pg/mg creatinine (1.30--2.07). Conversely, in 89 smokers, the geometric mean of 4-ABP concentration was significantly greater, at 8.69 pg/mg creatinine (7.43--10.16), p < 0.001. Our results indicate that following tobacco smoke exposure, total urinary 4-ABP is a reliable biomarker for exposure to this carcinogen. [ABSTRACT FROM AUTHOR]

Isothiocyanates (ITCs) found in cruciferous vegetables have been associated with a reduced cancer risk in humans. We determined serum albumin adducts of allyl isothiocyanate (AITC), benzylisothiocyanate (BITC), phenylethylisothiocyanate (PEITC) and sulforaphane (SFN) in 85 healthy men from a dietary, randomized, controlled trial. After enzymatic digestion of albumin we determined the adducts of the ITCs with lysine (Lys) using liquid chromatography-tandem mass spectrometry. At the beginning of the study (and after 4 weeks) 4.7% (2.4%), 48.2% (35.3%), 5.9% (10.6%), and 24.7% (23.5%) of the samples were found positive for AITC-Lys, BITC-Lys, PEITC-Lys and SFN-Lys, respectively. This method enables the quantification of ITC adducts in albumin from large, prospective studies on diet and cancer. [ABSTRACT FROM AUTHOR]

Cytochrome P450 enzymes play a major role in the metabolism of several of the chemical carcinogens involved in the development of hepatocellular carcinoma (HCC). To investigate by immunohistochemistry interindividual differences in these enzymes, polyclonal antisera and immunoperoxidase staining were used to detect the expression of CYP1A1/2 and 3A4 in 37 surgical control tissues and 105 tumour and adjacent nontumour tissues of HCC cases from Taiwan. There was variability in the expression and staining pattern for both CYP1A1/2 and 3A4 in all tissue types. In tissues from controls, there was no correlation between P450 expression and smoking history or hepatitis B virus antigen status. Since these samples had been previously analysed for the DNA adducts of aflatoxin B[sub 1] (AFB[sub 1] ), a dietary mould contaminant, and 4-aminobiphenyl (4-ABP), a component of cigarette smoke, we also investigated the relationship between P450 levels and DNA adducts. 4-ABP-DNA adducts were higher in tissues with elevated levels of CYP1A1/2 (p= 0.02). Overall there was no relationship between CYP1A1/2 or CYP3A4 and AFB[sub 1] -DNA adducts in control tissues. Staining intensity for CYP1A1/2 and 3A4 followed the order: tumour tissues