Faster discharge with lactated ringers than normal saline in first 72 h of acute pancreatitis: A multicenter randomized trial.

OBJECTIVES: Data driven strategies for acute pancreatitis (AP) in pediatrics are limited; adult data suggests lactated ringers (LR) compared to normal saline (NS) resulted in favorable outcomes, but has not been studied in pediatrics. Our objective was to evaluate the efficacy of LR during the first 48 h of an AP episode compared with NS. STUDY DESIGN: A multisite randomized controlled clinical trial, from 2015 to 2020 (Clinical Trials.gov NCT03242473). Patients were randomized to exclusively LR or NS for the first 48 h. Primary outcomes were serial C-reactive protein (CRP) values. Secondary outcomes included other lab values, time to feeds, length of stay (LOS), systemic inflammatory response syndrome (SIRS) development, and progression to severe AP (SAP). RESULTS: We studied 76 patients (38 LR, 38 NS). CRP at 24 and 48 h were not significantly different between LR or NS group. Additionally, there were no differences in trends of BUN, amylase, lipase, SIRS status, or SAP development between the LR and NS group at 24 and 48 h. A higher proportion of LR patients (32%, 12/38) were discharged before 48 h compared to NS (13%, 5/38). The LR group had a significantly higher rate of discharge within the first 72 h compared to the NS group (p = 0.02). CONCLUSION: The use of LR was associated with a faster rate of discharge during the intervention period and in the first 72 h, but no other differences compared to NS. This reduction in length of hospitalization has significant implications for patients and healthcare costs.

Single-Center Analysis of Essential Laboratory Testing in Patients with Newly Diagnosed Celiac Disease.

OBJECTIVE: To analyze laboratory testing results from pediatric patients newly diagnosed with celiac disease to determine the usefulness of each test derived from recommended guidelines. METHODS: Serological testing at the time of diagnosis from patients enrolled in our celiac disease registry from January 2018 through December 2021 was reviewed. The incidence of abnormal laboratory results, routinely obtained as per the recommendations of Snyder et al and our institution's Celiac Care Index, was assessed. Rates of abnormal laboratory values and estimated costs associated with these screening measures were analyzed. RESULTS: Our data demonstrated abnormalities in all serological testing obtained at celiac diagnosis. Hemoglobin, alanine aminotransferase, ferritin, iron, and vitamin D screening were found to be abnormal with notable frequency. Only 7% of patients had an abnormal thyroid-stimulating hormone and <0.1% had an abnormal free T4. Nonresponse to hepatitis B vaccination was prominent, with 69% of patients considered nonimmune. Screening protocols as currently outlined in our Celiac Care Index resulted in an estimated cost of approximately $320 000 during our study. CONCLUSIONS: Review of screening laboratory results at our center reveals that abnormal values for several recommended measures are uncommon. Thyroid screening was infrequently abnormal and the usefulness of screening for hepatitis B at diagnosis is uncertain. Similarly, our data suggest that iron deficiency screening may be condensed effectively into hemoglobin and ferritin testing, eliminating the need for initial iron studies. Decreasing baseline screening measures could safely decrease the burden of testing on patients and overall healthcare expenditures.

Determination of N7-glycidamide guanine adducts in human blood DNA following exposure to dietary acrylamide using liquid chromatography/tandem mass spectrometry.

RATIONALE: Acrylamide is classified as a probable human carcinogen that is metabolised to glycidamide, which can covalently bind to DNA. The aim of this study was to investigate the formation of N7-glycidamide guanine (N7-GA-Gua) adducts in human blood DNA following exposure to acrylamide present in carbohydrate-rich foods as part of the normal human diet. METHODS: Lymphocyte DNA was extracted from blood samples obtained from healthy human volunteers. Following thermal depurination of the DNA samples, N7-GA-Gua adducts were quantified using a validated liquid chromatography/tandem mass spectrometry (LC/MS/MS) method incorporating a stable isotope labelled internal standard. Estimated dietary acrylamide intake was recorded by completion of food frequency questionnaires for the 24 hours prior to volunteer blood donation. RESULTS: An LC/MS/MS method was validated with a limit of detection of 0.25 fmol and a lower limit of quantitation of 0.50 fmol on column. N7-GA-Gua adducts were detected in human blood DNA with the levels ranging between 0.3 to 6.3 adducts per 108 nucleotides. The acrylamide intake was calculated from the food frequency questionnaires ranging between 20.0 and 78.6 µg. CONCLUSIONS: Identification and quantification of N7-GA-Gua adducts in the blood DNA of healthy volunteers suggests that dietary acrylamide exposure may lead to the formation of DNA adducts. This important finding warrants further investigation to ascertain a correlation between environmental/dietary acrylamide exposure and levels of DNA adducts.

Who's at Risk? A Prognostic Model for Severity Prediction in Pediatric Acute Pancreatitis.

OBJECTIVES: The aim of the study was to validate and optimize a severity prediction model for acute pancreatitis (AP) and to examine blood urea nitrogen (BUN) level changes from admission as a severity predictor. STUDY DESIGN: Patients from 2 hospitals were included for the validation model (Children's Hospital of the King's Daughters and Children's National Hospital). Children's Hospital of the King's Daughters and Cincinnati Children's Hospital Medical Center data were used for analysis of BUN at 24 to 48 hours. RESULTS: The validation cohort included 73 patients; 22 (30%) with either severe or moderately severe AP, combined into the all severe AP (SAP) group. Patients with SAP had higher BUN (P = 0.002) and lower albumin (P = 0.005). Admission BUN was confirmed as a significant predictor (P = 0.005) of SAP (area under the receiver operating characteristic [AUROC] 0.73, 95% confidence interval [CI] 0.60-0.86). Combining BUN (P = 0.005) and albumin (P = 0.004) resulted in better prediction for SAP (AUROC 0.83, 95% CI 0.72-0.94). A total of 176 AP patients were analyzed at 24-48 hours; 39 (22%) met criteria for SAP. Patients who developed SAP had a significantly higher BUN (P < 0.001) after 24 hours. Elevated BUN levels within 24 to 48 hours were independently predictive of developing SAP (AUROC: 0.76, 95% CI: 0.66-0.85). Patients who developed SAP had a significantly smaller percentage decrease in BUN from admission to 24 to 48 hours (P = 0.002). CONCLUSION: We externally validated the prior model with admission BUN levels and further optimized it by incorporating albumin. We also found that persistent elevation of BUN is associated with development of SAP. Our model can be used to risk stratify patients with AP on admission and again at 24 to 48 hours.

Maternal diet during pregnancy and micronuclei frequency in peripheral blood T lymphocytes in mothers and newborns (Rhea cohort, Crete).

PURPOSE: The study assessed whether diet and adherence to cancer prevention guidelines during pregnancy were associated with micronucleus (MN) frequency in mothers and newborns. MN is biomarkers of early genetic effects that have been associated with cancer risk in adults. METHODS: A total of 188 mothers and 200 newborns from the Rhea cohort (Greece) were included in the study. At early-mid pregnancy, we conducted personal interviews and a validated food frequency questionnaire was completed. With this information, we constructed a score reflecting adherence to the World Cancer Research Fund/American Institute for Cancer Research cancer prevention guidelines on diet, physical activity and body fatness. At delivery, maternal and/or cord blood was collected to measure DNA and hemoglobin adducts of dietary origin and frequencies of MN in binucleated and mononucleated T lymphocytes (MNBN and MNMONO). RESULTS: In mothers, higher levels of red meat consumption were associated with increased MNBN frequency [2nd tertile IRR = 1.34 (1.00, 1.80), 3rd tertile IRR = 1.33 (0.96, 1.85)] and MNMONO frequency [2nd tertile IRR = 1.53 (0.84, 2.77), 3rd tertile IRR = 2.69 (1.44, 5.05)]. The opposite trend was observed for MNBN in newborns [2nd tertile IRR = 0.64 (0.44, 0.94), 3rd tertile IRR = 0.68 (0.46, 1.01)], and no association was observed with MNMONO. Increased MN frequency in pregnant women with high red meat consumption is consistent with previous knowledge. CONCLUSIONS: Our results also suggest exposure to genotoxics during pregnancy might affect differently mothers and newborns. The predictive value of MN as biomarker for childhood cancer, rather than adulthood, remains unclear. With few exceptions, the association between maternal carcinogenic exposures during pregnancy and childhood cancer or early biologic effect biomarkers remains poorly understood.

Antitumour benzothiazoles. Part 32: DNA adducts and double strand breaks correlate with activity; synthesis of 5F203 hydrogels for local delivery.

Potent, selective antitumour AhR ligands 5F 203 and GW 610 are bioactivated by CYPs 1A1 and 2W1. Herein we reason that DNA adducts' generation resulting in lethal DNA double strand breaks (DSBs) underlies benzothiazoles' activity. Treatment of sensitive carcinoma cell lines with GW 610 generated co-eluting DNA adducts (R(2)>0.7). Time-dependent appearance of γ-H2AX foci revealed subsequent DNA double strand breaks. Propensity for systemic toxicity of benzothiazoles steered development of prodrugs' hydrogels for localised delivery. Clinical applications of targeted therapies include prevention or treatment of recurrent disease after surgical resection of solid tumours. In vitro evaluation of 5F 203 prodrugs' activity demonstrated nanomolar potency against MCF-7 breast and IGROV-1 ovarian carcinoma cell lines.

An organizational approach for the assessment of DNA adduct data in risk assessment: case studies for aflatoxin B1, tamoxifen and vinyl chloride.

The framework analysis previously presented for using DNA adduct information in the risk assessment of chemical carcinogens was applied in a series of case studies which place the adduct information into context with the key events in carcinogenesis to determine whether they could be used to support a mutagenic mode of action (MOA) for the examined chemicals. Three data-rich chemicals, aflatoxin B1 (AFB1), tamoxifen (Tam) and vinyl chloride (VCl) were selected for this exercise. These chemicals were selected because they are known human carcinogens and have different characteristics: AFB1 forms a unique adduct and human exposure is through contaminated foods; Tam is a pharmaceutical given to women so that the dose and duration of exposure are known, forms unique adducts in rodents, and has both estrogenic and genotoxic properties; and VCl, to which there is industrial exposure, forms a number of adducts that are identical to endogenous adducts found in unexposed people. All three chemicals produce liver tumors in rats. AFB1 and VCl also produce liver tumors in humans, but Tam induces human uterine tumors, only. To support a mutagenic MOA, the chemical-induced adducts must be characterized, shown to be pro-mutagenic, be present in the tumor target tissue, and produce mutations of the class found in the tumor. The adducts formed by AFB1 and VCl support a mutagenic MOA for their carcinogenicity. However, the data available for Tam shows a mutagenic MOA for liver tumors in rats, but its carcinogenicity in humans is most likely via a different MOA.

STrengthening the Reporting of OBservational studies in Epidemiology - Molecular Epidemiology (STROBE-ME): an extension of the STROBE statement.

Advances in laboratory techniques have led to a rapidly increasing use of biomarkers in epidemiological studies. Biomarkers of internal dose, early biological change, susceptibility and clinical outcomes are used as proxies for investigating interactions between external and/or endogenous agents and body components or processes. The need for improved reporting of scientific research led to influential statements of recommendations such as the STrengthening Reporting of OBservational studies in Epidemiology (STROBE) statement. The STROBE initiative established in 2004 aimed to provide guidance on how to report observational research. Its guidelines provide a user-friendly checklist of 22 items to be reported in epidemiological studies, with items specific to the three main study designs: cohort studies, case-control studies and cross-sectional studies. The present STrengthening the Reporting of OBservational studies in Epidemiology -Molecular Epidemiology (STROBE-ME) initiative builds on the STROBE statement implementing nine existing items of STROBE and providing 17 additional items to the 22 items of STROBE checklist. The additions relate to the use of biomarkers in epidemiological studies, concerning collection, handling and storage of biological samples; laboratory methods, validity and reliability of biomarkers; specificities of study design; and ethical considerations. The STROBE-ME recommendations are intended to complement the STROBE recommendations.

STrengthening the Reporting of OBservational studies in Epidemiology--Molecular Epidemiology (STROBE-ME): an extension of the STROBE statement.

Advances in laboratory techniques have led to a rapidly increasing use of biomarkers in epidemiological studies. Biomarkers of internal dose, early biological change, susceptibility and clinical outcomes are used as proxies for investigating interactions between external and / or endogenous agents and body components or processes. The need for improved reporting of scientific research led to influential statements of recommendations such as the STrengthening Reporting of OBservational studies in Epidemiology (STROBE) statement. The STROBE initiative established in 2004 aimed to provide guidance on how to report observational research. Its guidelines provide a user-friendly checklist of 22 items to be reported in epidemiological studies, with items specific to the three main study designs: cohort studies, case-control studies and cross-sectional studies. The present STrengthening the Reporting of OBservational studies in Epidemiology - Molecular Epidemiology (STROBE-ME) initiative builds on the STROBE statement implementing nine existing items of STROBE and providing 17 additional items to the 22 items of STROBE checklist. The additions relate to the use of biomarkers in epidemiological studies, concerning collection, handling and storage of biological samples; laboratory methods, validity and reliability of biomarkers; specificities of study design; and ethical considerations. The STROBE-ME recommendations are intended to complement the STROBE recommendations.

Detection of acetaldehyde derived N(2)-ethyl-2'-deoxyguanosine in human leukocyte DNA following alcohol consumption.

Epidemiological studies have shown an association between alcohol (ethanol) consumption and increased cancer risk. The effect of alcohol consumption on the levels and persistence of N(2)-ethylidene-2'-deoxyguanosine (N(2)-ethylidene-dG) formed by acetaldehyde, the oxidative metabolite of ethanol, in human leukocyte DNA was investigated. DNA was isolated from venous blood samples obtained from 30 male non-smoking individuals before consumption of alcohol (0h) and subsequently at 3-5h following the consumption of 150mL of vodka (containing 42% pure ethanol). Additional samples were collected 24h and 48h post-alcohol consumption. The levels of N(2)-ethyl-2'-deoxyguanosine (N(2)-ethyl-dG) in the DNA were determined following reduction of N(2)-ethylidene-dG with sodium cyanoborohydride using a liquid chromatography-tandem mass spectrometry selected reaction monitoring method. A slight time-dependent trend showing an increase and decrease in the levels of N(2)-ethyl-dG was observed following consumption of alcohol compared to time 0h, however, the differences were not statistically significant. The average levels of N(2)-ethyl-dG observed at 0h, 3-5h, 24h and 48h time points following ingestion of alcohol were 34.6±21.9, 35.1±21.0, 36.8±20.7 and 35.6±21.1 per 10(8) 2'-deoxynucleosides, respectively. In conclusion, alcohol consumption that could be encountered under social drinking conditions, does not significantly alter the levels of the acetaldehyde derived DNA adduct, N(2)-ethyl-dG in human leukocyte DNA from healthy individuals.

Effect of hepatic cytochrome P450 (P450) oxidoreductase deficiency on 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine-DNA adduct formation in P450 reductase conditional null mice.

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), formed during the cooking of foods, induces colon cancer in rodents. PhIP is metabolically activated by cytochromes P450 (P450s). To evaluate the role of hepatic P450s in the bioactivation of PhIP, we used Reductase Conditional Null (RCN) mice, in which cytochrome P450 oxidoreductase (POR), the unique electron donor to P450s, can be specifically deleted in hepatocytes by pretreatment with 3-methylcholanthrene (3-MC), resulting in the loss of essentially all hepatic P450 function. RCN mice were treated orally with 50 mg/kg b.wt. PhIP daily for 5 days, with and without 3-MC pretreatment. PhIP-DNA adducts (i.e., N-(deoxyguanosin-8-yl)-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine [dG-C8-PhIP]), measured by liquid chromatography-tandem mass spectrometry, were highest in colon (1362 adducts/10(8) deoxynucleosides), whereas adduct levels in liver were ∼3.5-fold lower. Whereas no differences in PhIP-DNA adduct levels were found in livers with active POR versus inactivated POR, adduct levels were on average ∼2-fold lower in extrahepatic tissues of mice lacking hepatic POR. Hepatic microsomes from RCN mice with or without 3-MC pretreatment were also incubated with PhIP and DNA in vitro. PhIP-DNA adduct formation was ∼8-fold lower with hepatic microsomes from POR-inactivated mice than with those with active POR. Most of the hepatic microsomal activation of PhIP in vitro was attributable to CYP1A. Our results show that PhIP-DNA adduct formation in colon involves hepatic N-oxidation, circulation of activated metabolites via the bloodstream to extrahepatic tissues, and further activation, resulting in the formation of dG-C8-PhIP. Besides hepatic P450s, PhIP may be metabolically activated mainly by a non-P450 pathway in liver.

STrengthening the Reporting of OBservational studies in Epidemiology - Molecular Epidemiology (STROBE-ME): an extension of the STROBE statement.

Advances in laboratory techniques have led to a rapidly increasing use of biomarkers in epidemiological studies. Biomarkers of internal dose, early biological change, susceptibility and clinical outcomes are used as proxies for investigating the interactions between external and/or endogenous agents and the body components or processes. The need for improved reporting of scientific research led to influential statements of recommendations such as the STrenghtening Reporting of Observational studies in Epidemiology (STROBE) statement. The STROBE initiative established in 2004 aimed to provide guidance on how to report observational research. Its guidelines provide a user-friendly checklist of 22 items to be reported in epidemiological studies, with items specific to the three main study designs: cohort studies, case-control studies and cross-sectional studies. The present STrengthening the Reporting of OBservational studies in Epidemiology - Molecular Epidemiology (STROBE-ME) initiative builds on the STROBE Statement implementing 9 existing items of STROBE and providing 17 additional items to the 22 items of STROBE checklist. The additions relate to the use of biomarkers in epidemiological studies, concerning collection, handling and storage of biological samples; laboratory methods, validity and reliability of biomarkers; specificities of study design; and ethical considerations. The STROBE-ME recommendations are intended to complement the STROBE recommendations.

Evaluation of urinary ribonucleoside profiling for clinical biomarker discovery using constant neutral loss scanning liquid chromatography/tandem mass spectrometry.

The patterns and levels of urinary excreted ribonucleosides which reflect RNA turnover and metabolism in humans offer the potential for early detection of disease and monitoring of therapeutic intervention. A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method employing constant neutral loss (CNL) scanning for the loss of the ribose moiety (132 u) was used to detect ribonucleosides in human urine and to evaluate this analytical platform for biomarker research in clinical trials. Ribonucleosides were stable and not influenced by the time spent at room temperature prior to freezing or long-term storage at -80 °C. Matrix effects caused variation in the mass spectrometer response which was dependent on the concentration of the analysed urine sample. For the use of urinary ribonucleoside profiling in clinical biomarker studies, adjustment of the urine samples to a common concentration prior to sample preparation is therefore advocated. Changes in the mass spectrometer response should be accounted for by the use of an internal standard added after sample preparation. Diurnal variation exceeded inter-day variation of an individual's ribonucleoside profile, but inter-person differences were predominant and allowed the separation of individuals against each other in a multivariate space. Due to considerable diurnal variation the use of spot urine samples would introduce unnecessary variation and should be replaced by the collection of multiple spot urine samples across the day, where possible. Should such a protocol not be feasible, biological intra-day and inter-day variation must be considered and accounted for in the data interpretation.

STrengthening the reporting of OBservational studies in Epidemiology-Molecular Epidemiology (STROBE-ME): an extension of the STROBE statement.

Advances in laboratory techniques have led to a rapidly increasing use of biomarkers in epidemiological studies. Biomarkers of internal dose, early biological change, susceptibility, and clinical outcomes are used as proxies for investigating the interactions between external and/or endogenous agents and the body components or processes. The need for improved reporting of scientific research led to influential statements of recommendations such as STrengthening Reporting of Observational studies in Epidemiology (STROBE) statement. The STROBE initiative established in 2004 aimed to provide guidance on how to report observational research. Its guidelines provide a user-friendly checklist of 22 items to be reported in epidemiological studies, with items specific to the three main study designs: cohort studies, case-control studies and cross-sectional studies. The present STrengthening the Reporting of OBservational studies in Epidemiology-Molecular Epidemiology (STROBE-ME) initiative builds on the STROBE Statement implementing 9 existing items of STROBE and providing 17 additional items to the 22 items of STROBE checklist. The additions relate to the use of biomarkers in epidemiological studies, concerning collection, handling and storage of biological samples; laboratory methods, validity and reliability of biomarkers; specificities of study design; and ethical considerations. The STROBE-ME recommendations are intended to complement the STROBE recommendations.

Strategies in case of positive in vivo results in genotoxicity testing.

At the 2009 International Workshop on Genotoxicity Testing in Basel, an expert group gathered to provide guidance on suitable follow-up tests to describe risk when basic in vivo genotoxicity tests have yielded positive results. The working group agreed that non-linear dose-response curves occur in vivo with at least some DNA-reactive agents. Quantitative risk assessment in such cases requires the use of (1) adequate data, i.e., the use of all available data for the selection of reliable in vivo models to be used for quantitative risk assessment, (2) appropriate mathematical models and statistical analysis for characterizing the dose-response relationships and allowing the use of quantitative and dose-response information in the interpretation of results, (3) mode of action (MOA) information for the evaluation and analysis of risk, and (4) reliable assessments of the internal dose across species for deriving acceptable margins of exposure and risk levels. Hence, the elucidation of MOA and understanding of the mechanism underlying the dose-response curve are important components of risk assessment. The group agreed on the need for (i) the development of in vivo assays, especially multi-endpoint, multi-species assays, with emphasis on those applicable to humans, and (ii) consensus about the most appropriate mathematical models and statistical analyses for defining non-linear dose-responses and exposure levels associated with acceptable risk.

Molecular evidence of perinatal transmission of Bartonella vinsonii subsp. berkhoffii and Bartonella henselae to a child.

Bartonella vinsonii subsp. berkhoffii, Bartonella henselae, or DNA of both organisms was amplified and sequenced from blood, enrichment blood cultures, or autopsy tissues from four family members. Historical and microbiological results support perinatal transmission of Bartonella species in this family. It is of clinical relevance that Bartonella spp. may adversely influence human reproductive performance.

Determination of cisplatin 1,2-intrastrand guanine-guanine DNA adducts in human leukocytes by high-performance liquid chromatography coupled to inductively coupled plasma mass spectrometry.

Platinum-containing drugs are widely used to treat cancer in a variety of clinical settings. Their mode of action involves the formation of DNA adducts, which facilitate apoptosis in cancer cells. Cisplatin binds to the N7 position of the purine DNA bases forming intrastrand cross-links between either two adjacent guanines [cis-Pt(NH(3))(2)d(pGpG), 1,2-GG] or an adjacent adenine and guanine [cis-Pt(NH(3))(2)d(pApG), 1,2-AG)]. The cytotoxic efficacy for each of the different types of DNA adducts and the relationship between adduct levels in tumor cells and blood are not well understood. By using these Pt-containing adduct species as biomarkers, information on a patient's response to chemotherapy would be directly related to the mode of action of the drug. This type of analysis requires the most sensitive and specific methods available, to facilitate detection limits sufficient to measure the DNA adduct in the limited sample quantities available from patients. This was achieved in the current study by coupling a highly specific enzyme-based adduct isolation method with a sensitive detection system based on HPLC coupled to inductively coupled plasma mass spectrometry to measure the 1,2-GG cisplatin adducts formed in DNA. The method was developed and validated using calf thymus DNA and two different adenocarcinoma cell lines. The values for the limit of detection (LOD) and the limit of quantitation determined for the 1,2-GG cisplatin adduct were 0.21 and 0.67 fmol per microg DNA, respectively. This corresponds to an absolute LOD of 0.8 pg as Pt for the 1,2-GG adduct. Cisplatin-sensitive (H23) and -resistant (A549) tumor cells were exposed to the drug, and the 1,2-GG adduct levels were measured over a 24 h time period. The results showed a statistically significant (P < 0.05) higher concentration in the sensitive cells as compared to the resistant cells after repair for 7 h. Although the adduct concentration present fell at subsequent time points (12 and 24 h), the levels in each cell line were broadly similar. The protocol was then applied to the analysis of patient samples taken before and then 1 h after treatment. The 1,2-GG cisplatin adduct was present in the range from 113 to 1245 fg Pt per microg DNA in all of the patient samples taken after treatment. Although the adduct was not present at levels greater than the LOD in the initial pretreatment samples, trace amounts were discernible in some patient samples on their third treatment cycle.

Phosphotriester adducts (PTEs): DNA's overlooked lesion.

In addition to reacting with DNA base moieties, many chemical genotoxins also react with the oxygen atoms of the internucleotidic phosphodiester linkages to form phosphotriester adducts (PTEs). In view of their stability under physiological conditions, it has been suggested that PTEs may be useful biomarkers for measuring cumulative genotoxin exposure. The methodology for their determination is varied and still not completely developed but includes determination of hydrolysis products and (32)P-postlabelling approaches. More recently, transalkylation and direct mass spectrometry techniques have been devised, which give extra chemical information on the structures of the PTEs. The proportion of DNA damage formed as PTEs is much greater with SN1 compared to SN2 alkylating agents, and it has been shown in DNA that the formation of PTEs is partially sequence dependent. PTEs have been considered to be refractory to repair in mammalian cells but repair mechanisms have been found in prokaryotic cells, e.g. PTEs in Escherichia coli are repaired by O(6)-methylguanine-DNA methyltransferase (O(6)-MGT or Ada protein). However, studies on in vivo persistence of PTEs in mammalian systems have not ruled out the possibility of a contribution from an active repair process for PTEs. The biological significance of PTEs is largely unstudied and unknown, although effects of PTEs on DNA polymerases, and some exo- and endonucleases have been observed. Also site-specific PTEs impair the repair processing of adjacent sites of DNA damage, which may be a biological mechanism of importance for these lesions. In this review, we will consider the analytical methods available for the determination of PTEs, their stability in vitro and in vivo, the mechanisms for their repair, their possible biological significance and their potential role as biomarkers in human molecular epidemiology studies.

Cytogenetic and DNA damage on workers exposed to styrene.

Styrene is a commercially important chemical widely used in the manufacture of synthetic rubber, resins, polyesters and plastics. The highest levels of human exposure to styrene occur during the production of reinforced plastic products. The objective of this work was to evaluate both DNA and cytogenetic damage in styrene-exposed workers, analysing only non-smoker individuals. Environmental levels of styrene and urinary concentrations of mandelic and phenylglyoxylic acids were determined, and genetic damage was studied by means of micronucleus (MN) test, sister chromatid exchanges (SCEs) and comet assay. Fifty-two fibreglass-reinforced plastics workers and 54 controls took part in the study. The mean air concentration of styrene in the breathing zone of workers exceeded the threshold limit value, and 24 workers exceeded the biological exposure index. A strong and significant correlation was found between styrene environmental concentrations and urinary metabolites. Higher SCE rate (P<0.01) was observed in exposed workers than in controls. Besides, significant correlations were obtained for SCE rate with both environmental and internal exposure parameters (r=0.496, P<0.01 and r=0.511, P<0.01, respectively). Results from MN test and comet assay showed slight and non-significant increases related to the exposure. Our data seem to support previous studies reporting genotoxicity associated with occupational exposure to styrene, excluding the confounding influence of smoking, although caution must be taken in the interpretation of these results since the significance of an increase in SCE rate is still unclear.

Primary CNS anaplastic diffuse large B-cell lymphoma mimicking undifferentiated metastatic tumors: a case report.

Primary central nervous system lymphoma (PCNSL) is a rare intracranial tumor, with an annual incidence of six per million population. Anaplastic variant of primary CNS diffuse large B-cell lymphoma is less common; to our knowledge, there is only one other case report in the world literature. We describe a 71 year old immunocompetent female without significant past medical history who presented with confusion and a homogeneously enhancing midline mass. The patient underwent craniotomy for tumor biopsy, followed by high-dose methotrexate-based chemotherapy despite a remarkably low performance status. Histologically, this tumor was composed of undifferentiated polymorphic tumor cells, multi-nucleated giant cells, extensive necrosis, and conspicuous mitotic activity, mimicking undifferentiated metastatic tumors. Immunohistochemical stains demonstrated immunopositivity of tumor cells for CD20, MUM-1, and BCL-6, and negative staining for CD3, CD10, and CD30. The clinical course, diagnostic workup, pathologic correlates, and treatment outcomes are described.