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Alkylation of human serum albumin by sulfur mustard in vitro and in vivo: mass spectrometric analysis of a cysteine adduct as a sensitive biomarker of exposure.

To develop a mass spectrometric assay for the detection of sulfur mustard adducts with human serum albumin, the following steps were performed: quantitation of the binding of the agent to the protein by using [(14)C]sulfur mustard and analysis of acidic and tryptic digests of albumin from blood after exposure to sulfur mustard for identification of alkylation sites in the protein. The T5 fragment containing an alkylated cysteine could be detected in the tryptic digest with micro-LC/tandem MS analysis. Attempts to decrease the detection limit for in vitro exposure of human blood by analysis of the alkylated T5 fragment were not successful. After Pronase treatment of albumin, S-[2-[(hydroxyethyl)thio]ethyl]Cys-Pro-Phe was analyzed by means of micro-LC/tandem MS, allowing a detection limit for in vitro exposure of human blood of 10 nM, which is 1 order of magnitude lower than that obtained by means of modified Edman degradation. The analytical procedure could be successfully applied to the analysis of albumin samples from Iranian victims of the Iran-Iraq war.

Alkylating Agents↗

Molecular biomarkers for aflatoxins and their application to human cancer prevention.

The rapidly expanding understanding of the progressive processes of carcinogenesis provides opportunities for the identification of molecular biological markers reflecting events from exposure through clinical disease. These molecular biological markers can be classified into categories of markers of exposure reflecting the dose of toxic agents, markers of effect indicating a biological response to exposure, and markers of susceptibility providing information about the inherent sensitivity of individuals to the toxic agents. By definition some of these markers are chemical agent specific, such as a carcinogen-DNA or -protein adduct, while others are biological process specific, such as the altered expression of a gene. This article reviews the development and validation of molecular biomarkers of aflatoxins using experimental and human population studies. The development of molecular biomarkers for aflatoxins is based upon the extensive research database available about their metabolism, macromolecular adduct formation, and general mechanisms of action. The long-term goal of the research described in this paper is the application of aflatoxin biomarkers to the development of preventive interventions in human populations at high risk for liver cancer.

Aflatoxins↗

[Multi-biomarker approach to acute coronary syndrome].

High-risk acute coronary syndrome is characterized by vulnerable-plaque with subocclusive thrombus and down-stream microemboli spreading minor myocardial damage, resulting in non-ST-elevation myocardial infarction. Advances in the understanding of the pathogenesis and consequences of acute coronary syndrome have stimulated development of novel biomarkers, and expanded their role in the different spectrum of the underlying pathophysiology, namely multi-biomarker strategy; consisted of biomarkers for 1) myocardial necrosis(membrane damage to myofibril necrosis), 2) plaque destabilization, 3) myocardial stress(ischemic stress per se and end-diastolic atrial or ventricular wall stress), 4) myocardial ischemia, and 5) inflammatory process. In this article, we review clinical importance of novel biomarkers referring our previous clinical investigation and other reports, especially troponin T for detection of minor myocardial damage associated with vulnerable plaque with thrombus/embolus, heart-type fatty acid -binding protein for earlier detection of myocardial damage and it's role for the rule-out triage, N-terminal pro-BNP for earlier risk stratification in cardiac emergency, and soluble CD40 ligand for earlier identification of plaque destabilization with platelet activation in non-ST-elevation acute coronary syndrome.

Angina, Unstable↗

Development and validation of a plasma miRNA-CEA biomarker panel for early detection of lung cancer.

Lung cancer remains a leading cause of cancer-related mortality worldwide, underscoring the critical need for early detection to improve patient outcomes. This study aimed to develop and validate a plasma microRNA biomarker panel for the early detection of non-small cell lung cancer in a Japanese cohort. We enrolled 525 participants, comprising 261 LC cases and 264 non-LC controls, divided into optimization and validation cohorts. A 12-miRNA panel was optimized and further combined with CEA to enhance diagnostic performance. The miRNA-alone model demonstrated robust performance in both the optimization (AUC = 77.0%) and validation cohorts (AUC = 77.9%). Integration with CEA significantly improved accuracy, achieving AUCs of 86.2% in optimization and 84.9% in validation, with particularly high performance in late-stage cancers (AUC = 94.4%) and squamous cell carcinoma (AUC = 90.7%). Sensitivity and specificity thresholds were evaluated, enabling model customization for diverse clinical scenarios. These findings highlight the potential of the miRNA-CEA panel as a minimally invasive tool for early LC detection, especially in non-smoking populations.

Humans↗

Development of a gas chromatographic test for the quantification of the biomarker 3-bromopropionic acid in human urine.

An accurate and precise method was developed for the detection and quantification of 3-bromopropionic acid (3-BPA), a metabolite and biomarker for exposure to 1-bromopropane (1-BP). 1-BP is used as an industrial solvent and exposure is a health concern for industrial workers due to its toxicity. It has been associated with neurological disorders in both animals and humans. Urine sample preparation for the determination of 3-BPA consisted of liquid-liquid extraction (LLE) with ethyl acetate and silylation with N-methyl-N-[tert-butyldimethylsilyl]trifluoroacetamide (MTBSTFA). Quantification was by means of a gas chromatograph (GC) equipped with a mass selective detector (MSD) using a dimethylpolysiloxane (HP-1) capillary column and 3-chloropropionic acid was used as an internal standard in the procedure. Demonstrated accuracy and precision during this method's validation was good; recovery varied between 93 and 98% with relative standard deviations (R.D.S.) of 5.7% or less. The limit of detection (LOD) for the procedure was approximately 0.01microg/ml 3-BPA in urine. These data and other factors of the development and validation of this test method will be discussed.

Biomarkers↗

Blood biologic markers of stroke: improved management, reduced cost?

Identifying blood biomarkers may be of particular value in neurologic disorders such as stroke because of the difficulty in directly studying the brain and its blood vessels. Markers of brain injury, inflammation, excitotoxicity, and oxidative damage have been evaluated for their value in stroke diagnosis, treatment, and management, but none have proved to be sensitive or specific enough for routine clinical use. However, new cellular and molecular profiling approaches using the peripheral blood offer the potential for identifying panels of genes and proteins by increasing specificity while maintaining sensitivity. Furthermore, the first biomarker for predicting stroke risk associated with atherosclerosis (lipoprotein-associated phospholipase A2) was recently approved by the United States Food and Drug Administration. The ultimate aim for stroke biomarkers is to develop rapid, easy to use, widely available, and inexpensive diagnostic tests that can be used in the clinic and in clinical trials.

Biomarkers↗

Discriminatory proteomic biomarker analysis identifies free hemoglobin in the cerebrospinal fluid of women with severe preeclampsia.

OBJECTIVE: Preeclampsia is an idiopathic multisystem disorder specific to human pregnancy. This study used proteomic analysis of cerebrospinal fluid (CSF) to identify protein biomarkers characteristic of preeclampsia and related to its severity. STUDY DESIGN: CSF was collected from women diagnosed clinically with severe preeclampsia (sPE: n = 7), mild preeclampsia (mPE: n = 8), and normotensive controls (CRL: n = 8). Samples were subjected to proteomic analysis using surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF) mass spectroscopy. A discriminative proteomic biomarker profile was extracted by applying Mass Restricted analysis, and a Preeclampsia Proteomic Biomarker (PPB) score developed based on the presence or absence of four discriminatory protein peaks in individual CSF SELDI tracings. In-gel tryptic digests, Western blot analysis, on-chip immunoassays, ELISA, and spectral analysis were used to identify the biomarkers composing the PPB score. RESULTS: PPB score distinguished patients with a clinical diagnosis of sPE from mPE and CRLs. (PPB median [range]: sPE: 4 [0-4] vs mPE: 1 [0-1] vs CRL: 0 [0-0]; P < 0.001). PPB scores were unaffected by parity, magnesium seizure prophylaxis, CSF leukocyte counts, and total protein content. Proteomic identification techniques matched the discriminatory protein peaks to the alpha- and beta-hemoglobin chains. ELISA confirmed that women diagnosed clinically with sPE had significantly higher CSF hemoglobin concentrations than women with mPE or CRL (median [range]: sPE: 6.6 [0.0-10.3] microg/mL vs mPE: 0 [0-1.3] microg/mL vs CRL: 0 [0-0] microg/mL; P < 0.001). CONCLUSION: Proteomic analysis of CSF can accurately distinguish sPE from both mPE and CRL. Patients with sPE have nanomolar amounts of free hemoglobin in their CSF. Further studies are needed to confirm these observations and determine their physiologic implications.

Biomarkers↗

Development and validation of a drug activity biomarker that shows target inhibition in cancer patients receiving enzastaurin, a novel protein kinase C-beta inhibitor.

PURPOSE: To evaluate the effects of the novel protein kinase C (PKC) inhibitor enzastaurin on intracellular phosphoprotein signaling using flow cytometry and to use this approach to measure enzastaurin effects on surrogate target cells taken from cancer patients that were orally dosed with this agent. EXPERIMENTAL DESIGN: The activity of PKC was assayed in intact cells using a modification of published techniques. The U937 cell line and peripheral blood mononuclear cells were stimulated with phorbol ester, fixed, permeabilized, and reacted with an antibody specific for the phosphorylated forms of PKC substrates. The processed samples were quantitatively analyzed using flow cytometry. The assay was validated for selectivity, sensitivity, and reproducibility. Finally, blood was obtained from volunteer cancer patients before and after receiving once daily oral doses of enzastaurin. These samples were stimulated ex vivo with phorbol ester and were assayed for PKC activity using this approach. RESULTS: Assay of U937 cells confirmed the selectivity of the antibody reagent and enzastaurin for PKC. Multiparametric analysis of peripheral blood mononuclear cells showed monocytes to be the preferred surrogate target cell. Day-to-day PKC activity in normal donors was reproducible. Initial results showed that five of six cancer patients had decreased PKC activity following enzastaurin administration. In a following study, a group of nine patients displayed a significant decrease in PKC activity after receiving once daily oral doses of enzastaurin. CONCLUSION: An inhibition of surrogate target cell PKC activity was observed both in vitro and ex vivo after exposure to the novel kinase inhibitor, enzastaurin.

Antineoplastic Combined Chemotherapy Protocols↗

A urinary biomarker for uptake of dietary isothiocyanates in humans.

Isothiocyanates (ITCs) are a family of biologically active compounds that are distributed widely in cruciferous vegetables. Although studies in rodents have shown that these compounds are effective and versatile inhibitors of tumorigenesis, the role of dietary ITCs in the protection against human cancers remains to be established. A prerequisite of human studies is to develop an uptake biomarker for dietary ITCs. In this study, we describe a rapid high-performance liquid chromatography-based assay to measure the total ITC level in human urine. This assay is based on a previously described reaction of ITCs or their thiol conjugates with 1,2-benzenedithiol to yield a cyclocondensation product, 1,3-benzodithiole-2-thione, which then can be quantified by reverse phase high-performance liquid chromatography with UV detection. This new assay was validated by analyzing urine samples from 14 subjects who had consumed a known amount of watercress or brown mustard in a controlled experiment. The N-acetylcysteine conjugates of phenethyl ITC and allyl ITC from watercress and brown mustard, respectively, were quantified and compared with the results obtained from the current assay. Results of the two methods were highly correlated (r = 0.978), indicating the specificity of this new assay for dietary ITCs. The feasibility of this assay for population-based studies was examined using stored urine samples collected from nine participants of a prospective cohort study in Shanghai, China, who indicated that they were daily consumers of dark green vegetables. There was a 10-fold variation in urinary ITC contents among these samples, ranging from 0.7 to 7.0 micromol/g creatinine. These results show the potential use of this uptake biomarker in epidemiological studies to identify the role of dietary ITCs in modifying cancer risks in humans.

Anticarcinogenic Agents↗

Association of polymorphisms within androgen receptor, 5alpha-reductase, and PSA genes with prostate volume, clinical parameters, and endocrine status in elderly men.

BACKGROUND: The aim of this study was to assess the impact of polymorphisms of three genes within the androgen pathway on prostate volume, clinical parameters, and endocrine status. METHODS: Elderly men with lower urinary tract symptoms underwent clinical and endocrine work-up. In parallel, polymorphisms within the 5alpha-reductase gene (SRD5A2 V89L and A49T), the androgen receptor gene (AR; number of CAG repeats), and the prostate specific antigen (PSA) gene (A --> G substitution at position-158) were determined by polymerase chain reaction and restriction-length polymorphism analysis by using DNA from peripheral blood. RESULTS: A total of 190 men (66.5 +/- 9.2 yr) were analyzed. The number of CAG repeats within the AR and the PSA polymorphism revealed no associations to clinical and endocrine parameters. Individuals carrying the mutated SRD5A2 A49T allele (5.3% of the total population) had larger prostates (54.1 vs. 39.3 ml), higher PSA levels (12.2 vs. 4.3 ng/ml), and a 35% reduction in prostatic stroma/epithelial cell ratio. Men with the mutated SRD5A2 V89L gene had lower testosterone levels. CONCLUSIONS: In contrast to prostate cancer, polymorphisms within AR and PSA genes do not seem to be of importance for benign prostatic hyperplasia. Polymorphisms within the 5alpha-reductase gene are interesting biomarkers for the development of benign prostatic hyperplasia and benign prostatic enlargement.

Aged↗

Pb enamel biomarker: deposition of pre- and postnatal Pb isotope injection in reconstructed time points along rat enamel transect.

Exposure to lead (Pb) as well as other heavy metals in the environment is still a matter of public health concern. The development of the enamel biomarker for heavy metal exposure assessment is designed to improve studies of dose-effect relationships to developmental anomalies, particularly embryonic dysfunctions, and to provide a time-specific recount of past exposures. The work presented in this paper demonstrates maternal transfer across the placental barrier of the enriched isotope (206)Pb tracer to the enamel of the rat pup. Likewise, injections of (204)Pb-enriched tracer in the neonate rat resulted in deposition of the tracer in the enamel histology as measured by secondary ion microprobe spectrometry. Through enamel, we were able to observe biological removal and assimilation of prenatal and postnatal tracers, respectively. This research demonstrates that enamel can be used as a biomarker of exposure to Pb and may illustrate the toxicokinetics of incorporating Pb into fetal and neonatal steady-state system processes. The biomarker technique, when completely developed, may be applied to cross-sectional and longitudinal epidemiological research.

Animals↗

Gamma-glutamyltransferase and diabetes--a 4 year follow-up study.

AIMS/HYPOTHESIS: Gamma-glutamyltransferase (GGT) is located on the external surface of most cells and mediates the uptake of gluthathione, an important component of intracellular antioxidant defenses. An increase in GGT concentration has been regarded as a marker of alcohol consumption or liver disease. However, more subtle gradations in GGT could be informative because its expression is enhanced by oxidative stress and it could be released by several conditions inducing cellular stress. Recently, serum GGT concentrations have been associated with many cardiovascular disease risk factors or components of the insulin resistance syndrome. We did a prospective study with the hypothesis that serum GGT is a predictor of incident diabetes. METHODS: A total of 4,088 healthy men working in a steel manufacturing company were examined in 1994 and 1998. Diabetes was defined as a serum fasting glucose concentration of more than 126 mg/dl or the use of diabetes medication. RESULTS: There was a strong dose-response relation between serum GGT concentrations at baseline and the incidence of diabetes. In contrast to the 31% of men with GGT concentrations under 9 U/l, adjusted relative risks for incidence of diabetes for GGT concentrations 10-19, 20-29, 30-39, 40-49, and over 50 U/l were 8.0, 13.3, 12.6, 19.6 and 25.8, respectively. The associations of age and BMI with incident diabetes became stronger the higher the value of baseline serum GGT concentration. CONCLUSION/INTERPRETATION: This study suggests that an increase in GGT concentration within its physiological range is a sensitive and early biomarker for the development of diabetes.

Adult↗

Clinical trials in neuroprotection. 23-25 January 2003, Key Biscayne, Florida, USA.

Many common neurological and psychiatric disorders are accompanied by extensive neuronal loss, either acutely or chronically. These include stroke, head trauma, spinal cord injury, epilepsy, perinatal and perioperative hypoxia-ischaemia, Alzheimer's and Parkinson's diseases, amyotrophic lateral sclerosis (ALS) and even some aspects of schizophrenia and depression. Despite considerable research effort, no agent has been found that can protect the brain from any of these neurodegenerative conditions. 'Clinical Trials in Neuroprotection,' sponsored by the University of Pennsylvania, was held to address this situation in a unique way. Rather than focus on one neurodegenerative condition, the conference brought together researchers from a variety of neuroprotection areas. They reviewed basic mechanisms of neuronal injury, the animal models used in a variety of paradigms and the design and results of clinical trials in many neuroprotection areas. The presentations and extensive discussions focused on common issues encountered and lessons learned, and on developing innovative strategies for clinical evaluation of potential neuroprotective agents. Conference participants came to a general consensus that some mechanisms were the same for all conditions, models need to be improved, new clinical trial paradigms should consider drug combinations and/or sequential administration of neuroprotective agents, new biomarkers should be developed and a 'proof-of-principle' trial would be widely valuable and should be developed.

Animals↗

DNA adduct level in lung tissue may act as a risk biomarker of lung cancer.

Lung cancer is a leading cause of mortality in Taiwan. We hypothesised that high susceptibility to DNA damage in the target organ acts as a risk biomarker for the development of lung cancer. To verify this hypothesis, the aromatic/hydrophobic DNA adduct levels of non-tumorous adjacent lung tissues from 73 primary lung cancer patients and 33 non-cancer controls were evaluated by 32P-postlabelling assay. Wilcoxon rank sum test showed that DNA adduct levels in lung cancer patients (49.58+/-33.39 adducts/10(8) nucleotides) were significantly higher than those in non-cancer controls (18.00+/-15.33 adducts/10(8) nucleotides, P<0.001). The DNA adduct levels among lung cancer and non-cancer samples were not influenced by smoking behaviour and cigarette consumption. Our data also showed that the polymorphisms of cytochrome P4501A1 (CYP1A1) Msp1, glutathione S-transferase M1 (GSTM1) and the combination of both genetic polymorphisms were not related to the DNA adduct levels. Interestingly, positive association between CYP1A1 protein expression and DNA adduct levels was found when CYP1A1 protein expression in lung specimens from lung cancer patients was examined by immunohistochemistry. Multivariate linear regression analysis indicated that the DNA adduct level was not associated with gender, smoking behaviour, or genetic polymorphisms of CYP1A1 and GSTM1. Moreover, multivariate logistic regression analysis showed that persons with high DNA adduct levels (>48.66 adducts/10(8) nucleotides) had an approximately 25-fold risk of lung cancer compared with persons with low DNA adduct levels (</=48.66 adducts/10(8) nucleotides). In conclusion, DNA adduct levels in lung tissue may be a more reliable lung cancer susceptibility biomarker than DNA adduct levels in leucocytes. In addition, higher susceptibility to DNA damage in lung cancer patients may partly play a role in the development of lung cancer.

Adenocarcinoma↗

Value of p53 expression in oral cancer and adjacent normal mucosa in relation to the occurrence of multiple primary carcinomas.

Paraffin embedded, formalin fixed tissue sections from patients suffering from a primary oral squamous cell carcinoma were immunohistochemically investigated for the presence of p53 expression using the Bp53-11 antibody. The aim of this study was to determine the predictive value of p53 expression as a biomarker for the development of a second primary tumour (SPT) in the respiratory and upper digestive tract. In a nested case control study, neoplastic and normal tissue sections of 44 patients who had a previous history of cancer were used. 15 of the 44 had developed a SPT, while the other 29 were minimally 7 years free of disease. Additionally, nine SPTs were included in this study to establish whether concordance exists in tumours that develop in the same field. 10 of the 29 patients (34%) free of tumour during follow-up had p53 positive tumours. 8 of 15 patients (53%) who developed a SPT had a p53 positive primary tumour. This difference is not statistically different (chi 2-test). Forty percent of the total group of primary oral cavity tumours showed p53 positivity. When comparing the first and the second tumours, discordance in p53 expression between the first and second tumours was seen in 4 out of 9 cases. None of the cases showed p53 positivity in adjacent normal mucosa. In conclusion, p53 immunoreactivity in neoplasia, dysplasia and normal tissue does not predict the development of a SPT. In addition, multiple primary tumours do not have identical p53 expression.

Adult↗

Contribution of dietary protein and inorganic sulfur to urinary sulfate: toward a biomarker of inorganic sulfur intake.

BACKGROUND: Sulfiting agents are widely used as food additives. Limits are set on their use in foods because they may adversely affect health. Sulfiting agents are excreted in urine as sulfate, which is indistinguishable from sulfate derived from sulfur amino acids. OBJECTIVE: The objective was to assess the contribution of inorganic sulfur to urinary sulfate excretion and of dietary protein to urinary sulfate and nitrogen excretion with the aim of developing a urinary biomarker of inorganic sulfur intake. DESIGN: Nine healthy men were fed a sequence of 3 diets for 15 d (n = 7), 5 diets for 10 d (n = 6), or both. The diets contained 51-212 g protein/d (0.43-1.71 g S/d) and 0.17-0.27 g inorganic S/d; p-aminobenzoic acid-validated 24-h urine samples (n = 47) were analyzed for sulfate and nitrogen. RESULTS: Dietary inorganic sulfur was efficiently excreted as sulfate in urine. Urinary sulfate derived from protein correlated strongly (r(2) = 0.86) with urinary nitrogen. Urinary recovery of protein sulfur and nitrogen decreased from 84% at average protein intakes (72 g/d) to 70% at high protein intakes (212 g/d). The nitrogen:sulfur ratio (in g) of the protein in the study diets was 18.9, which was maintained in urine (18.4 +/- 0.1) after dietary inorganic sulfur intake was subtracted from urinary sulfate. Therefore, inorganic sulfur intake (g/d) = urinary sulfur (g/d) - 0.054 x urinary nitrogen (g/d). For typical UK intakes of inorganic sulfur (0.25 g/d), this biomarker should produce mean (+/- SD) values of 0.24 +/- 0.10 g S/d. CONCLUSION: Twenty-four-hour urinary nitrogen and sulfate values can be used to predict inorganic sulfur intake.

Adult↗

Current status of biomarkers for melanoma metastasis.

There is a critical unmet need for new predictive and prognostic biomarkers for melanoma. This feature presents a brief overview of the opportunities and challenges facing investigators who are seeking biomarkers that can predict those melanomas that are likely to result in progression (metastasis) and death. Melanoma metastasis to the regional lymph nodes is now readily identified by sentinel node biopsy. However, currently available prognostic factors, which are based on clinical parameters and histological findings in the primary tumor, are limited in their ability to reliably discriminate which patients will manifest sentinel node metastasis and/or disseminated disease. To date, even those biomarkers for which substantial clinical correlation has been obtained have suffered from both conflicting data in clinical trials involving different patient populations and poorly understood interactions between the biomarkers and other established prognostic factors. An understanding of whether biomarker data should be viewed as a continuum or be categorized based on discrete breakpoints is also frequently lacking. In many cases, biomarkers are initially developed based on unequivocal index cases, such as clearly benign or clearly malignant melanocytic lesions, but then fail as predictive tools when applied to the more difficult cases that arise in clinical practice; such cases occupy a 'gray' zone that is filled with uncertainty and lacks an established 'gold standard' against which a biomarker prediction can be validated.

Animals↗