[Gene expression and environmental exposure to xenobiotics: overview and applications]

Industrial chemicals, pesticides, pharmaceuticals, foods, heavy metals, air pollutants, and naturally occurring substances, are an integral part of our daily lives. Environmental exposure can induce changes in gene regulation associated with human diseases. A new discipline of toxicology is "predictive toxicology" that defines the relationship between the structure and activity of the genome and the adverse biological effects of exogenous agents. Toxicogenomic technologies allow complete assessment of the functional activity of biochemical pathways, and of the structural genetic (sequence) differences among individuals (polymorphisms), that were previously unattainable. Microarray technology provides the means to study multiple pathways and mechanisms at concurrent times. Gene expression is a sensitive indicator of toxicant exposure, disease state, and cellular metabolism and thus represents a way of characterising how cells and organisms adapt to changes in the external environment. The application of these technologies to toxicology can lead us into a new era when genotypes and toxicant-induced genome expression, proteins, and metabolite patterns can be used to screen compounds for hazard identification, to monitor individual exposure to toxicants, to track cellular responses to different doses, to assess mechanisms of action, and to predict individual variability in sensitivity to toxicants and potential ways to improve risk assessment.

Recovery of visual functions after early acquired occipital damage

Plasticity of visual systems after early brain damage has been extensively studied in animal models but poorly documented in children after visual pathway lesions. This report describes the visual recovery of a male child who had a bilateral occipital lobe infarction at the age of 2 years 6 months, 10 days after colon resection for Hirschsprung disease. In the acute phase he had severe visual impairment without visual response. Some weeks later he could perceive movement. Since then, progressive recovery of his visual acuity and oculomotor abilities has been accompanied by a progressive reduction of the visual field defect. At 6 years 8 months, visual recognition acuity was 10/10 in both eyes and neuro-ophthalmological examination was normal, except for persistence of the visual field defect in the upper hemifield and a selective impairment of higher visual functions (recognition of object presented in a hard-to-decode way [e.g. overlapping figures], or use of complex visuospatial skills). The functional recovery observed in this patient confirms the adaptive plasticity of developing visual systems after early brain lesions. It suggests that in humans, as in animal models, processes related to cerebral plasticity may take place years after a brain lesion has been sustained.

Genome-wide screening of copy number alterations and LOH events in renal cell carcinomas and integration with gene expression profile

Background

Clear cell renal carcinoma (RCC) is the most common and invasive adult renal cancer. For the purpose of identifying RCC biomarkers, we investigated chromosomal regions and individual genes modulated in RCC pathology. We applied the dual strategy of assessing and integrating genomic and transcriptomic data, today considered the most effective approach for understanding genetic mechanisms of cancer and the most sensitive for identifying cancer-related genes.

Results

We performed the first integrated analysis of DNA and RNA profiles of RCC samples using Affymetrix technology. Using 100K SNP mapping arrays, we assembled a genome-wide map of DNA copy number alterations and LOH areas. We thus confirmed the typical genetic signature of RCC but also identified other amplified regions (e.g. on chr. 4, 11, 12), deleted regions (chr. 1, 9, 22) and LOH areas (chr. 1, 2, 9, 13). Simultaneously, using HG-U133 Plus 2.0 arrays, we identified differentially expressed genes (DEGs) in tumor vs. normal samples. Combining genomic and transcriptomic data, we identified 71 DEGs in aberrant chromosomal regions and observed, in amplified regions, a predominance of up-regulated genes (27 of 37 DEGs) and a trend to clustering. Functional annotation of these genes revealed some already implicated in RCC pathology and other cancers, as well as others that may be novel tumor biomarkers.

Conclusion

By combining genomic and transcriptomic profiles from a collection of RCC samples, we identified specific genomic regions with concordant alterations in DNA and RNA profiles and focused on regions with increased DNA copy number. Since the transcriptional modulation of up-regulated genes in amplified regions may be attributed to the genomic alterations characteristic of RCC, these genes may encode novel RCC biomarkers actively involved in tumor initiation and progression and useful in clinical applications.

Dioxin exposure, from infancy through puberty, produces endocrine disruption and affects human semen quality

BACKGROUND

Environmental toxicants are allegedly involved in decreasing semen quality in recent decades; however, definitive proof is not yet available. In 1976 an accident exposed residents in Seveso, Italy, to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).

OBJECTIVE

The purpose of this study was to investigate reproductive hormones and sperm quality in exposed males.

METHODS

We studied 135 males exposed to TCDD at three age groups, infancy/prepuberty (1-9 years), puberty (10-17 years), and adulthood (18-26 years), and 184 healthy male comparisons using 1976 serum TCDD levels and semen quality and reproductive hormones from samples collected 22 years later.

RESULTS

Relative to comparisons, 71 men (mean age at exposure, 6.2 years; median serum TCDD, 210 ppt) at 22-31 years of age showed reductions in sperm concentration (53.6 vs. 72.5 million/mL; p = 0.025); percent progressive motility (33.2% vs. 40.8%; p < 0.001); total motile sperm count (44.2 vs. 77.5 x 10(6); p = 0.018); estradiol (76.2 vs. 95.9 pmol/L; p = 0.001); and an increase in follicle-stimulating hormone (FSH; 3.58 vs. 2.98 IU/L; p = 0.055). Forty-four men (mean age at exposure, 13.2 years; median serum TCDD, 164 ppt) at 32-39 years of age showed increased total sperm count (272 vs. 191.9 x 10(6); p = 0.042), total motile sperm count (105 vs. 64.9 x10(6); p = 0.036), FSH (4.1 vs. 3.2 UI/L; p = 0.038), and reduced estradiol (74.4 vs. 92.9 pmol/L; p < 0.001). No effects were observed in 20 men, 40-47 years of age, who were exposed to TCDD (median, 123 ppt) as adults (mean age at exposure, 21.5 years).

CONCLUSIONS

Exposure to TCDD in infancy reduces sperm concentration and motility, and an opposite effect is seen with exposure during puberty. Exposure in either period leads to permanent reduction of estradiol and increased FSH. These effects are permanent and occur at TCDD concentrations < 68 ppt, which is within one order of magnitude of those in the industrialized world in the 1970s and 1980s and may be responsible at least in part for the reported decrease in sperm quality, especially in younger men.

[HCV genotyping in health professionals: controversies and perspectives]

Healthcare workers (HCW) are at risk of acquiring blood-borne infections, including HCV Although current evidence does not suggest an increased prevalence of HCV infection among HCW, transmission of infection following occupational exposure has been demonstrated. Moreover, HCV can establish a persistent, chronic infection contributing to progressive liver disease, and post-exposure prophylaxis against HCV infection is not currently available. Problems still arise in the health surveillance of healthcare workers HCV infected. The use of virologic assays has become essential in the management of hepatitis C virus (HCV) infection, in order to improve the diagnosis of the infection, to guide the treatment decisions, and to assess the virologic response to antiviral therapy. Although several studies have specifically evaluated the role of HCV genotypes, many questions have not been answered. It is thought that HCV genotypes are important epidemiological markers, but more investigations are needed to elucidate their role regarding the progression and the pathogenesis of liver disease. The clinical implication of HCV genome heterogeneity, the different genotyping methods and the possible role of HCV genotypes as a parameter that could help health surveillance of infected HCW are described in this paper.

ENA Screen Chemiluminescence Immunoassay: A Random Access Method in Autoimmunology

Recently, autoimmunity, due to an increase in examination requests, has become an independent area of laboratory research, which needs management optimization in terms of quality, time, and flexibility. Therefore, we have evaluated the screening of extractable nuclear antigens (ENA) antibodies both with a chemiluminescence immunoassay and the enzyme-linked immunosorbent assay (ELISA) method, which was used in our laboratory, as a reference kit. The most important difference between these two methods is the possibility of processing serum samples with a random access system, which is different from batch methods.

[Virus C hepatitis: successful therapy in a health care worker]

Hepatitis C viral is a problem of population health. The World Health Organization considers Hepatitis C an epidemic, a "silent" epidemic because a patient living with Hepatitis C can be infected for decades before being discovered. Recent data show an estimated number of 170 million patients infected with hepatitis C virus in the world. Number of new infections per year has declined from an average of 240,000 in the 1980s to about 26,000 in 2004. The incidence of HCV infected patients is estimated to 500-600 new cases in a year in Italy. Chronic infection is present in 55%-85% of infected persons. Approximately one third of the patients develop cirrhosis over a number of years, which can lead to liver failure and other serious complications. There is no vaccine and no completely effective treatment. Recent data show PEG-IFN-RBV combination therapy is most effective. We describe one HCV infected individual case report with HCV genotype 1b who received combination therapy for 4 weeks. Levels of HCV RNA became undetectable after an mouth of treatment.

[New tools for the study of occupational allergies related to animals]

Animal laboratory workers are exposed at the Laboratory Animal Allergy (LAA). About 10% of them develop asthma. Currently, by the use of innovative methodologies, numerous allergens from the laboratory animals have been sequenced and analyzed. Between them, the allergens by rats and mouse, the experimental models more utilized. Proteomic approach or protein microarray permit the study of several allergens, belonging to the proteins known as lipocalins, and of immunological response in susceptible individuals. Moreover, availability of on-line data banks permit a knowledge more and more detailed and up-to-date regarding the allergens of the interest. Between the advantage of the proteomic there is the use of small amount of biological fluids, as the serum, in association with the possibility to studied a great number of allergens on a single support. The study of LAA by the use of proteomic will permit to identify the animal allergens more accurately, providing also a valid tool at the methodologies traditionally used, and for the planning of the preventive and protective measures.

Leber's congenital amaurosis: is there an autistic component?

There is much evidence in the literature suggesting that children with congenital blindness can also present autistic like features. The aetiopathogenetic and clinical significance of this association is still unclear. Given the central role played by vision in development, we set out to establish the significance of autistic-like behaviours in children with early-onset severe visual impairment. Our sample comprised 24 children (13 males, 11 females; mean age 5y 2mo; range 2-11y) affected by Leber's congenital amaurosis (LCA). The results of our administration of a modified Childhood Autism Rating Scale--excluding item VII (Visual Responsiveness)--showed that only four of the children gave an overall score indicating the presence of autism (moreover, of mild/moderate degree). Hardly any of the children in our LCA sample presented major dysfunctions in their relationships with other people or in their social and emotional responsiveness, thus allowing us to exclude a genuine comorbidity with a picture of autism. Indeed, the risk facing the visually impaired child seems to concern their early interactive experiences, which may be affected by their inability to connect with others, and may be prevented through the development of specific strategies of intervention.

[QuantiFERON-TB Gold test in homeless shelter staff: preliminary results]

Tuberculosis (TB) continues to be a major cause of disability and death and it has become a real problem in industrialized countries. The spread of HIV, the increasing immigration rate of people from countries with endemic TB and the growth of drug-resistant Mycobacterium tuberculosis strains extend its impact. Since the spread of the infection occurs early, health care workers are particularly exposed to the risk of contracting and/or transmitting the mycobacterium. In health care settings, policies and procedures for TB control should be developed, including health surveillance. Until recently the tuberculin skin test was the only available method for diagnosing tuberculosis, however it suffers several methodological weaknesses: high rate of false positive results in vaccinated populations, the subjectivity of the evaluation and the booster effect. Recently, the introduction of new in vitro serological tests, as the Quantiferon TB-Gold in tube (QFT-TB), may overcome these problems. The QFT-TB is based on the quantification of interferon-gamma released from sensitized lymphocytes in whole blood incubated overnight with PPD from M. tuberculosis and control antigens. The present study was performed on 27 nuns (homeless shelter staff) who were at risk for contracting tuberculosis. The prevalence of positive tests was 15 out 27 (55.5%).

[Emerging infectious diseases among swine workers]

In the last years emerging infections represent an important problem of public health and occupational medicine. Biological agents and their hosts exist in a precariously balanced and continuously evolving relationship, influenced by their environment. RNA viruses are responsible for most of the emerging diseases. Epidemics that recently affected the world of work are zoonoses, such as cases of SARS in healthcare staff Dutch poultry workers infected with the avian virus A/H7N7 in 2003, the current threat of avian flu A/H5N1 to poultry workers. Workers at risk include those who are in contact with live or dead infected animals, with aerosols, dust or surfaces contaminated by animal secretions, persons engaged in animal breeding and trade, veterinaries, and others. Pigs are at risk of acquiring many viral and bacterial diseases and, consequently, could be able to transmit some of these infections to occupationally exposed subjects. The aim of our study is to set out some emerging zoonosis that could affect swine workers, an occupational sector where a proper assessment of biological risks is difficult to perform.

[Brugada syndrome and work place: two case report]

Brugada Syndrome (BS) is a primary electrical disease of the heart that causes sudden cardiac death or life-threatening ventricular arrhythmias. This disease is hereditary syndrome genetically determined. The pattern of transmission is autosomic dominant. Several mutations linked to this syndrome affecting the gene SCN5A which encodes for the cardiac sodium channel have been described. Recent studies showed the disease is responsible for 4 to 50% of sudden deaths. A typical electrocardiographic (ECG) finding consists of the ST-segment elevation in the right precordial leads. These ECG patterns, which appears permanently or intermittently in patients, are unmasked by antiarrhythmic agents. This syndrome has a very poor prognosis when left untreated: one third of patients having suffered from syncopal episodes or resuscitated from near-sudden death develops a new episode of ventricular tachycardia within 2 years. The only available treatment is the implantable cardioverter-defibrillator. We report two cases of probable BS in workers exposed to occupational risks. These case reports demonstrate the importance of surveillance, particularly of cardiac examination for identifying patients at risk of ventricular arrhythmogenic events.

Apolipoprotein E polymorphisms influence effect of pravastatin on survival after myocardial infarction in a Mediterranean population: the GISSI-Prevenzione study

AIMS

Controversy exists with regard to the influence of APOE polymorphisms on coronary heart disease development and on the efficacy of statin treatment. we investigated the relationship between apoe, mortality and the response to treatment in Mediterranean myocardial infarction (mi) survivors.

METHODS AND RESULTS

We analysed 3304 Italian patients with MI randomized to pravastatin or no treatment in the GISSI-Prevenzione study, with a mean follow-up time of 23.0 +/- 6.7 months (median 24.3 months). Mortality curves were calculated using Kaplan-Meier method, and differences in survival were tested using the log-rank test. There were 109 deaths during follow-up. Patients treated with pravastatin showed a significant decrease in mortality compared with non-treated patients (HR 0.67, 95% confidence interval 0.45-0.97, P = 0.038). Among the 3304 patients, 554 (16.8%) were epsilon4 carriers and 2750 (83.2%) were non-epsilon4 carriers. No significant difference in terms of mortality was observed between the epsilon4 and the non-epsilon4 carriers (3.61% vs. 3.24%, P = 0.67). However, although in non-epsilon4 carriers no significant difference in mortality was observed between patients treated with pravastatin and non-treated (2.81% vs. 3.67%, P = 0.21), among the epsilon4 carriers a significant reduction in mortality was observed in patients treated compared with non-treated (1.85% vs. 5.28%, P = 0.023).

CONCLUSION

We found that epsilon4 allele is a determinant of pravastatin response in terms of survival. Though in the entire population investigated,we found a beneficial effect of pravastatin in terms of survival, only the epsilon4 carriers seemed to have gained a significant benefit from this treatment. We suggest that the effect of statins is of particular interest in this fraction of the population. Genetic markers can help in identifying patients that benefit more from statin treatment.

On-line detection of atmospheric formaldehyde by a conductometric biosensor

Atmospheric formaldehyde (CH(2)O) was detected under continuous flow conditions by an on-line system comprising of a wet scrubber for a continuous transfer of the pollutant to an aqueous solution, a micro-reactor containing immobilized formaldehyde dehydrogenase (FDH) and a conductometric transducer. By this system atmospheric formaldehyde concentrations in the range 0.05-2 ppm were detected with a sensitivity of 20 microS/ppm. In this concentration range the immobilized enzyme oxidized all the sampled formaldehyde molecules to formic acid, avoiding cumbersome calibration procedures. The operational stability of the biosensor was at least 3 months, working continuously 10 h/day at room temperature.

[The need to improve the quality of laboratory results in the study of biological occupational risk]

In the field of occupational medicine, the laboratory medicine gives fundamental contribution not only to evaluate the risk connected to different environmental, biologic, chemical and physical factors, but also to manage the quality of the work condition. For this purpose, it's fundamental that the finalized health efficiency measures and the individuation of interventions partially or totally based on laboratory results, have to be correlated to reliable analytical results, to be validated by internal and external quality controls. During the last years, a new and in some way innovative interest in occupational exposition to biological agents increased. Although, in this sphere, the immunoenzimatic methods are widely used, standardization and quality controls are often absent. For the molecular investigation that is widely used in occupational medicine, adequate quality control systems should be promoted. The work medicine, as the laboratory medicine, should develop "Quality Assurance" programmes not only referred to different occupational infections study, but also to the use of different laboratory methodologies, including immunochemical, cellular, molecular or the ones ending by ... omic as proteomic, genomic, transcriptomic, etc.. The carrying out of such programmes is necessary to aim to support the integration in the involved different professional positions, to guarantee higher comprehension, transparency and reliability on analytical results.

[Occupational medicine and new risks]

Technological and socio-economic changes in the world of work are having a strong impact on the life of individuals and organizations. Individuals expect security, a feeling of belonging, and recognition; organizations constantly demand more flexibility, participation and productivity. Inside this growing gap we find today's new risks: they reflect at-risk work settings, where organizational "discomfort" is most likely to develop. Against this backdrop, dominated by a feeling of precariousness, workers have to re-visualize their jobs. This is a complicated and tiring process, as they have to demolish the old models they already have in their minds, so they can replace them with new, more appropriate ones. Occupational medicine has a role on two levels in this process. The first, close to the workers themselves, calls for the ability to understand the new risks, interpreting them in relation to the organizational settings. The second involves a path within the discipline, crossing over the first role but in the opposite direction to the usual one: from the dominant model of medicine by classification to reinstatement of the clinical dimension. This attributes importance to a research approach to problems, and calls for the construction of networks both within occupational medicine and between disciplines.

[Biosafety in laboratories concerning exposure to biological agents]

Laboratory workers are exposed to a variety of potential occupational health hazards including those deriving from infectious materials and cultures, radiations, toxic and flammable chemicals, as well as mechanical and electrical hazard. Although all of them are significant, this paper will focus on biological hazards present in clinical and research laboratories. In fact, in spite of numerous publications, guidelines and regulations, laboratory workers are still subject to infections acquired in the course of their researches. This paper describes some aspects that include good microbiological practices (GMPs), appropriate containment equipment, practices and operational procedures to minimize workers' risk of injury or illness.

Auditory attention at the onset of West syndrome: correlation with EEG patterns and visual function

At the onset of West syndrome a specific impairment of visual function has been clearly demonstrated, while other aspects of sensorial development, and in particular of the auditory function, have been less studied. The aim of this study was to evaluate auditory function and orienting responses at the onset of West syndrome, and to relate the results with EEG patterns, visual function and neurodevelopmental competence. A prospective multicentric study was performed on 25 successively enrolled infants with West syndrome; all the patients underwent a full clinical assessment, including MRI and video-EEG, visual function and auditory orienting responses (AORs) as well as Griffiths' developmental scales. The whole assessment performed at the onset of spasms (T0) was repeated after two months (T1). AORs resulted significantly impaired both at T0 and T1. At the onset of spasms a highly significant relationship of auditory attention with visual function and neurodevelopmental competence was shown in both cryptogenic and symptomatic forms, but it was no longer present after two months. Our results may suggest a possible pervasive effect of the epileptic disorder on sensory processing, associated to a deficit of neurodevelopment. Although we failed to show a significant correlation between auditory orienting responses and EEG patterns, some evidence seems to support at least partially an influence of the epileptic disorder per se on the genesis of the sensorial impairment. A longer follow up and a larger cohort will be useful for a better clarification of these findings.

Linkage analysis of quantitative traits for obesity, diabetes, hypertension, and dyslipidemia on the island of Kosrae, Federated States of Micronesia

Obesity, diabetes, hypertension, and heart disease are highly heritable conditions that in aggregate are the major causes of morbidity and mortality in the developed world and are growing problems in developing countries. To map the causal genes, we conducted a population screen for these conditions on the Pacific Island of Kosrae. Family history and genetic data were used to construct a pedigree for the island. Analysis of the pedigree showed highly significant heritability for the metabolic traits under study. DNA samples from 2,188 participants were genotyped with 405 microsatellite markers with an average intermarker distance of 11 cM. A protocol using loki, a Markov chain Monte Carlo sampling method, was developed to analyze the Kosraen pedigree for height, a model quantitative trait. Robust quantitative trait loci for height were found on 10q21 and 1p31. This protocol was used to map a set of metabolic traits, including plasma leptin to chromosome region 5q35; systolic blood pressure to 20p12; total cholesterol to 19p13, 12q24, and 16qter; hip circumference to 10q25 and 4q23; body mass index to 18p11 and 20q13; apolipoprotein B to 2p24-25; weight to 18q21; and fasting blood sugar to 1q31-1q43. Several of these same chromosomal regions have been identified in previous studies validating the use of loki. These studies add information about the genetics of the metabolic syndrome and establish an analytical approach for linkage analysis of complex pedigrees. These results also lay the foundation for whole genome scans with dense sets of SNPs aimed to identifying causal genes.

Prevalence and incidence of antibodies to Borrelia burgdorferi and to tick-borne encephalitis virus in agricultural and forestry workers from Tuscany, Italy

The ticks Ixodes persulcatus and Ixodes ricinus are the main vectors of both Borrelia burgdorferi sensu lato and tick-borne encephalitis (TBE) virus in Eurasia. Borrelia burgdorferi is the cause of Lyme borreliosis, and TBE is a biphasic meningoencephalitis induced by an arbovirus belonging to the flavivirus family. The principal aims of the current investigation were (i) to determine the frequency of serological evidence of Borrelia burgdorferi sensu lato and TBE infections in healthy agricultural and forestry workers, (ii) to determine the incidence of seroconversion for antibodies against Borrelia burgdorferi sensu lato and TBE virus in Tuscan workers during a 1-year survey; and (iii) to assess the occupational risk for agricultural and forestry activities in a defined area (Tuscany, Italy). A total of 412 blood samples were taken from agricultural and forestry workers, and information on age, duration of employment, and history of tick bites was collected in a questionnaire to establish the risk factors for the diseases. Three hundred sixty-five blood donors from the same region served as controls. To estimate the rate of seroconversion, 176 of the agricultural and forestry workers were tested 1 year later. IgG and IgM antibodies against Borrelia burgdorferi sensu lato and TBE virus were detected in serum by an enzyme-linked immunosorbent assay and confirmed by Western blot analysis for Borrelia burgdorferi and by a test for inhibition of hemagglutination for TBE. Antibodies against Borrelia burgdorferi were more frequent among the workers than in the control group (7.8% vs. 4.9% in the IgG-IgM enzyme-linked immunosorbent assay and 7.03% vs. 3.56% in the confirmatory test). No seropositivity was observed for TBE virus. Eighteen of 176 subjects who underwent a second blood test developed specific antibodies against Borrelia burgdorferi within 1 year.

C-Reactive Protein in Heart Failure

Background— The role of C-reactive protein (CRP) in heart failure is not well studied. We assessed the prognostic value of CRP in patients randomized in Val-HeFT (Valsartan Heart Failure Trial) and studied changes in CRP that were associated with valsartan.

Methods and Results— Characteristics of patients with baseline CRP levels above and below the median value were compared. Univariable and multivariable Cox proportional hazards regression models were used to examine the relationship of CRP to mortality and morbidity. Interactions were tested to determine whether differences in CRP changes from baseline to 4 and 12 months between groups randomly assigned to valsartan or placebo depended on baseline ACE inhibitor use. Median plasma CRP was 3.23 mg/L (interquartile range 1.42 to 7.56 mg/L), which is higher than in the general population. Patients with CRP above the median had features of more severe heart failure than those with CRP levels below the median. The cumulative likelihood of death and first morbid event increased with increasing quartile of CRP. Relative to the lowest CRP quartile, the risk of mortality (hazard ratio 1.51, 95% CI 1.2 to 1.9) and first morbid event (hazard ratio 1.53, 95% CI 1.28 to 1.84) was increased in the highest CRP quartile in multivariable models. CRP added incremental prognostic information to that provided by brain natriuretic peptide alone. CRP did not change significantly over time in the placebo group; however, after 12 months, valsartan was associated with a decrease in CRP in patients not receiving ACE inhibitors but not in those receiving ACE inhibitors at 12 months.

Conclusions— CRP is increased in heart failure. Higher levels are associated with features of more severe heart failure and are independently associated with mortality and morbidity. The ability of treatments to reduce CRP levels and the prognostic importance of reducing CRP require further study.

Prognostic significance of the long pentraxin PTX3 in acute myocardial infarction

BACKGROUND

Inflammation has a pathogenetic role in acute myocardial infarction (MI). Pentraxin-3 (PTX3), a long pentraxin produced in response to inflammatory stimuli and highly expressed in the heart, was shown to peak in plasma approximately 7 hours after MI. The aim of this study was to assess the prognostic value of PTX3 in MI compared with the best-known and clinically relevant biological markers.

METHODS AND RESULTS

In 724 patients with MI and ST elevation, PTX3, C-reactive protein (CRP), creatine kinase (CK), troponin T (TnT), and N-terminal pro-brain natriuretic peptide (NT-proBNP) were assayed at entry, a median of 3 hours, and the following morning, a median of 22 hours from symptom onset. With respect to outcome events occurring over 3 months after the index event, median PTX3 values were 7.08 ng/mL in event-free patients, 16.12 ng/mL in patients who died, 9.12 ng/mL in patients with nonfatal heart failure, and 6.88 ng/mL in patients with nonfatal residual ischemia (overall P<0.0001). Multivariate analysis including CRP, CK, TnT, and NT-proBNP showed that only age > or =70 years (OR, 2.11; 95% CI, 1.04 to 4.31), Killip class >1 at entry (OR, 2.20; 95% CI, 1.14 to 4.25), and PTX3 (>10.73 ng/mL) (OR, 3.55; 95% CI, 1.43 to 8.83) independently predicted 3-month mortality. Biomarkers predicting the combined end point of death and heart failure in survivors were the highest tertile of PTX3 and of NT-proBNP and a CK ratio >6.

CONCLUSIONS

In a representative contemporary sample of patients with MI with ST elevation, the acute-phase protein PTX3 but not the liver-derived short pentraxin CRP or other cardiac biomarkers (NT-proBNP, TnT, CK) predicted 3-month mortality after adjustment for major risk factors and other acute-phase prognostic markers.

Prevalence of Pathogenic Mutations in an Italian Clinical Series of Patients with Familial Dementia

Genetic factors are involved in the aetiology of dementias. Three genes have been identified which, when mutated, cause Familial Alzheimer disease (FAD): the presenilin-1 (PS1), the presenilin-2 (PS2) and the amyloid precursor protein (APP) genes. Together, these mutations are responsible for 30-50% of the cases with autosomal dominant Alzheimer disease (AD), and for about 5% of all AD cases. While over 130 mutations have been identified in PS1, mutations in PS2 and APP are rarer, since only 10 and 22 mutations, respectively, have been found in these FAD genes. Instead, mutations in the MAPT gene were associated with Familial Frontotemporal dementia (FFTD) linked to chromosome 17 (FTDP-17). Frontotemporal dementia (FTD) can occur in a sporadic form, but in 30-50% of cases there is a positive family history of dementia. In this study, we determined the spectrum of mutations and the relative contribution of the above mentioned four genes in our Italian clinical series of patients with a positive family history of dementia.

[Occupational exposure to endocrine disruptors: state of the art]

Research into how exposure to "endocrine disrupters chemicals" affects human health is attracting increasing attention among European and international scientists since these contaminants are so widespread in the home and work environment and can have far-reaching effects on mental and physical health. Here we draw a general picture of studies to date on specific occupational exposures to single chemicals such as bisphenol A, styrene, etc., or homogeneous groups such as pesticides, metals, dioxins, phthalates and others. Although the exposure occurs in different ways, the toxic mechanisms of action vary widely, and it is hard to establish precisely the conditions of occupational exposure, significant correlations are nevertheless evident between the potential dose and its effects and further studies are certainly needed. There is still much debate on the epidemiological methods employed, which may overestimate exposure. The "measure" or at least an accurate description of exposure conditions is critical to the whole question and attempts to ensure this involve standardized procedures and statistical tests as the basis for a protocol for assessing the risk of occupational exposure. Investigations to date have focused on the effects on the reproductive system, in males in particular. However, considering the broad range of equilibria and systems on which endocrine destructive compounds can act, the international scientific community needs to persist in its efforts to develop methods for checking the effects on other endocrine organs--particularly the thyroid gland--and on the immune and neurological systems.

BACE-2 is overexpressed in Down's syndrome

Brain deposition of the amyloid-beta protein (Abeta) is a frequent complication of Down's syndrome (DS) patients. Abeta peptide is generated by endoproteolytic processing of Abeta precursor protein by gamma and beta secretases. Recently a transmembrane aspartyl protease, BACE, has been identified as the beta-secretase, and its homologous BACE-2 has also been described. BACE-2 gene resides on chromosome 21 in the obligate DS region. It cleaves Abeta precursor protein at its beta site and more efficiently at a different site within Abeta. In the present study we characterized the BACE-2 gene and protein expression in the DS patients and healthy control. We analyzed, by using a nonradioactive ribonuclease protection assay, the levels of BACE-2 mRNA expression in primary skin fibroblasts. The analysis revealed a 2.6-fold increase in BACE-2 mRNA levels in the DS group compared to the levels observed in the control group. Western blot analysis revealed no difference between DS and control in BACE-2 protein levels in the intracellular compartment. In the medium conditioned by fibroblast, we revealed an evident secretion of BACE-2 protein, represented by two different molecular weights, remarkably increased in DS fibroblasts. BACE-2 overexpression was also confirmed in the DS fetal brains and human neural embryonic DS stem cells in which conditioned media BACE-2 was secreted. These data highlight the importance of the extracellular compartment where BACE-2 overexpression could play a role in plaque formation in DS patients.

[SARS and occupational risk]

SARS is an infectious disease caused by a previously unrecognized human coronavirus, called SARS-associated coronavirus (SARS-CoV). Current information indicates that most transmission is via respiratory droplets coming from a person who is symptomatic with SARS ("close contact"). The aim of our study is to evidence the critical role of the family physician, the first health-care worker who cares with suspected/probable SARS patients, underlying the importance of the correct use and management of the personal protective equipment.

[Health risk caused by exposure to low-dose chemical agents at research laboratories]

In literature there are many works on the exposure to organic solvents and its risk. In research laboratories the risk valuation is really problematic due to different variables such as low dose, multiple exposure to substances with different characteristic of hazardous. We analyzed the blood exams of workers of seven biomedical research laboratories for finding a correlation between exposition and the variability of some parameters.

Variations in lipoprotein levels after myocardial infarction and unstable angina: the LATIN trial

BACKGROUND

The aim of this study was to prospectively evaluate the magnitude of the variations in lipid levels in a large population of patients admitted for acute myocardial infarction (MI) and unstable angina (UA). Clinical data and blood samples were prospectively collected from consecutive patients with MI and UA.

METHODS

The study population consisted of patients with symptoms lasting < or = 12 hours (for MI) or with the last episode of rest pain within 12 hours and associated with ECG changes (for UA). The exclusion criteria were recent hospitalization for any reason or current treatment with lipid-lowering drugs. Blood samples were obtained at admission, the following morning, at discharge and after 3 months. Samples were centrifuged immediately and 4 aliquots of serum were stored at -20 degrees C. The measurements were performed centrally.

RESULTS

We enrolled 1864 patients (1275 with MI and 589 with UA). Serum levels of total and LDL-cholesterol decreased significantly after admission, both in MI and UA patients. After 3 months, serum levels of total cholesterol returned to baseline, while those of LDL-cholesterol were still significantly lower. Between admission and the following morning, total and LDL-cholesterol decreased significantly by 7 and 10% respectively for MI and by 5 and 6% for UA. Lipid measurements not performed at admission accounted for a significant decrease in the number of patients identifiable as hyperlipidemic and suitable for lipid-lowering treatment (18% of MI patients and 11% of UA patients).

CONCLUSIONS

Serum cholesterol concentrations drop significantly during hospitalization for an acute coronary syndrome after a few hours from admission to the coronary care unit. Lipid profile assessment should be scheduled at admission in order to correctly identify hyperlipidemic patients.

HIV-1 multi-dideoxynucleoside resistance mutation (Q151M): prevalence, associated resistance mutations and response to antiretroviral salvage treatment

The prevalence and clinical implications of the Q151M multidrug-resistance mutation gene (mut) to antiretroviral drugs in the HIV reverse transcriptase (RT) gene have not yet been fully explained. In the present study three out of 350 (0.85%) of HIV-infected patients who underwent a drug-resistance genotyping assay because of therapeutic failure showed the Q151M mut. All these patients had been previously treated with zidovudine in association with didanosine. One such patient failed to respond to all salvage regimens tried and was shown to harbour some of the characteristic mut associated with Q151M (77L and 116Y). Another two patients partially responded to salvage regimens, both virologically and immunologically, and harboured the M184V mut in the RT gene. The prevalence of Q151M mut in our group was less (0.85%) than in other studies, which ranged from 2 to 19%. The M184V mut seemed to confer some viro-immunological benefit when associated with the Q151M mutation, compared with the latter alone.

[Delphi study in the identification of research need in occupational medicine in Italy]

The aim of the study was to identify the research priorities and strategies in Occupational Safety and Health (OSH) in Italy with a high degree of consensus. Based on the Delphi technique, a two-phase questionnaire was sent to experts at Universities, Local Health Units (ASLs) and Trade Unions. In the first phase, experts were requested to indicate three research topics in the OSH sector. A total of 27 topics for both universities and ASLs and 18 topics for Trade Unions were identified. In the second phase, experts were requested to assign a score from one (low relevance) to five (high relevance) to each topic previously identified. On the basis of a mean score reported for each topic, two ranked lists of priorities, one referred to universities and ASLs the other referred to Trade Unions, were formulated. The highest priority identified by universities and ASLs was occupational carcinogenesis, followed by quality in occupational medicine. Workers' information, education and participation was also identified with a high degree of priority. For Trade Unions, occupational cancers as well as training, information, participation and prevention awareness had the highest priority. Trade Unions also identify small-industries and occupational accidents as topics with high priority for research development. This study allowed a high degree of consensus to be reached regarding the research priorities in the OSH sector in Italy. Differences in the topics identified, or regarding the mean score of topics commonly identified, were related to the origin of the expert recruited to this study (University, ASLs or Trade Unions) and, for universities and ASLs, to the geographical area. In the authors' opinion, the full transfer of existing scientific data to occupational health practice and the harmonization of the priorities identified by this investigation are crucial if the research needs in the OSH sector in Italy are to be met.

Analysis of HIV-1 mutation patterns in patients failing antiretroviral therapy

The emergence of mutations encoding drug resistance is supposed to be a significant limitation to the clinical efficacy of inhibitor compounds directed against specific HIV-1 enzymatic targets. We have used a commercial test (Visible Genetics Inc., Paris, France) to study the prevalence of mutations occurred in HIV-1 protease and reverse transcriptase (RT) genes in 93 HIV-1 infected patients treated with at least one regimen containing a protease inhibitor (PI) and failing to the current therapeutic regimen. Protease mutations conferring resistance to at least one PI were detected in 46/93 (49.4%) of strains, 25 (26.8%) of which showed resistance to all PIs. Reverse transcriptase mutations conferring resistance to at least one RT inhibitor were detected in 57/93 (61.2%) of strains, 18 (19.3%) of which showed resistance to all RT inhibitors. The most frequent RT mutations were T215Y/F, M41L, and M184V (41.9, 40.8, and 40.8%, respectively), while L63P, L10R/V, and A71V/T (58, 41.9, and 34.4%, respectively) were the most represented protease substitutions. We have found no mutations encoding for multiple dideoxynucleoside resistance (Q151M or T69SS). Twelve of our patients (12.9%) had no mutation encoding drug resistance and were completely sensitive to all RT and protease inhibitors. Therefore, not all virological failures are caused by HIV-1 genomic resistance.

Non-specific influx of T-cell receptor alpha/beta and gamma/delta lymphocytes in mucosal biopsies from a patient with orofacial granulomatosis

Orofacial granulomatosis (OFG) represents an inflammatory disorder of the facial and oral mucosa, histologically characterized by non-caseating epithelioid cell granulomas. Since other granulomatous diseases have been shown to be characterized by a limited heterogeneity of alpha/beta and gamma/delta T cells, we investigated the T-cell diversity of both types of lymphocytes obtained from the same OFG patient. When we compared the T-cell receptor diversity of the lymphocytes accumulating at the site of the lesions with that of the peripheral blood counterpart, we did not find significant differences. Furthermore, no exclusive expansions of different T-cell clones were seen in the patient. From these data we conclude that, in this OFG patient, the majority of T cells have no specificity for a single or for a few antigens and that tissue accumulation of T lymphocytes is the result of a random influx of cells at the site of inflammation.

Environmental exposure to dioxin: the Seveso experience

The toxicity in humans of 2,3,7,8-tetrachlorodibenzo-p-dioxin, a man-made compound and environmental pollutant, is still debated. The industrial accident at Seveso, Italy, in 1976 exposed a large population of both sexes and of all ages to a massive concentration of 2,3,7,8-tetrachlorodibenzo-p-dioxin. Monitoring of soil and measurement of blood samples allowed classification of the exposed population into three categories: A, B and R (high, medium and low exposure, respectively). This article presents data from longitudinal health monitoring of the population, including liver function, immune function, neurological impairment, dermatological effects, reproductive pathology, and mortality.

Expansion of rare CD8+ CD28- CD11b- T cells with impaired effector functions in HIV-1-infected patients

The decline in the number of CD4+ T cells in HIV-1-infected patients is known to be related to the increased number of CD8+CD28- T cells. In this paper, we show that CD8+CD28- T cells from HIV-positive patients have an impaired capability to interact with human endothelial cells. This is due to the dramatic expansion, within this subset, of rare CD11b- cells lacking cell-cell adhesion functions. In 50 HIV-positive patients, 19.5% +/- 6.5% of all T cells were CD8+CD28-CD11b-, whereas only 0.8% +/- 0.4% of all T cells from healthy donors showed this uncommon phenotype. The percentage of circulating CD8+CD28-CD11b- T cells was strongly related to the percentage of CD4+ T cells (r = -0.82). This population is peculiar in terms of HIV infection and was found to possess some characteristics associated with effector functions but its cytotoxic properties were impaired. The percentage of target cells lysed by CD8+CD28-CD11b- was significantly lower than that of cells lysed by its CD11b- counterpart (p <.05) both at low (5:1) or at relatively high (20:1) effector/target ratios. CD8+CD28-CD11b- T cells, which lack the ability to interact with endothelial cells, are likely to accumulate and persist in circulation. The biologic properties of CD8+CD28-CD11b- T cells suggest that these cells might be endstage or aberrant differentiated effector cells. Lack of cell-cell adhesion and impaired cytolytic functions favor the hypothesis of a role for CD8+CD28-CD11b- T cells in the development of immunodeficiency.

PTX3, A prototypical long pentraxin, is an early indicator of acute myocardial infarction in humans

BACKGROUND

Inflammation is an important component of ischemic heart disease. PTX3 is a long pentraxin whose expression is induced by cytokines in endothelial cells, mononuclear phagocytes, and myocardium. The possibility that PTX3 is altered in patients with acute myocardial infarction (AMI) has not yet been tested.

METHODS AND RESULTS

Blood samples were collected from 37 patients admitted to the coronary care unit (CCU) with symptoms of AMI. PTX3 plasma concentrations, as measured by ELISA, higher than the mean+2 SD of age-matched controls (2.01 ng/mL) were found in 27 patients within the first 24 hours of CCU admission. PTX3 peaked at 7.5 hours after CCU admission, and mean peak concentration was 6.94+/-11.26 ng/mL. Plasma concentrations of PTX3 returned to normal in all but 3 patients at hospital discharge and were unrelated to AMI site or extent, Killip class at entry, hours from symptom onset, and thrombolysis. C-reactive protein peaked in plasma at 24 hours after CCU admission, much later than PTX3 (P<0.001). Patients >64 years old and women had significantly higher PTX3 concentrations at 24 hours (P<0.05). PTX3 was detected by immunohistochemistry in normal but not in necrotic myocytes.

CONCLUSIONS

PTX3 is present in the intact myocardium, increases in the blood of patients with AMI, and disappears from damaged myocytes. We suggest that PTX3 is an early indicator of myocyte irreversible injury in ischemic cardiomyopathy.

Restriction of T-cell receptor repertoires in idiopathic CD4+ lymphocytopenia

We report that alpha/beta and gamma/delta T-cell repertoires of three patients with idiopathic CD4+ lymphocytopenia, who showed different clinical manifestations and outcomes over time, were highly restricted. The disruption of T-cell repertoires does not influence the susceptibility to infections: the first patient was unable to attain a protective response to mycobacterium, the second showed clinical improvement and the third did not develop opportunistic infections. These results indicate that idiopathic CD4+ lymphocytopenia could give rise to mono-/oligoclonal T-cell expansions, but the degree of repertoire disturbance is not indicative of the severity of disease progression.

Serum dioxin levels in Seveso, Italy, population in 1976

On July 10, 1976, an explosion at a chemical plant near Seveso, Italy, released a mixture of chemicals, including 2,3,7,8-tetrachlorodibenzo-p-dioxin and 2,4,5-trichlorophenol. As a result, several thousand people in the Seveso area may have been exposed to those chemicals. At that time, human exposure assessment was based primarily on soil levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin. Medical examinations of this potentially exposed population and control subjects were begun in 1976 and in some cases continued until 1985. In 1988, we began assessing human exposure in this population by measuring 2,3,7,8-tetrachlorodibenzo-p-dioxin in small volumes of serum specimens remaining from the medical examinations. As expected, we found that the median serum dioxin levels were highest among people who lived closest to the explosion and were progressively lower among groups living farther away. These measurements have allowed us to assess exposure more accurately among individuals in this population and to relate exposure to various health effects. We found that some individuals in the exposed population had among the highest serum dioxin levels ever reported, yet chloracne was the only unequivocal effect found; cancer risks are still being investigated. We also found that other individuals with as high or higher serum dioxin levels did not develop chloracne. We also found that the serum half-life of dioxin in this population was 7-8 years, which agrees with other findings although we do report some differences in the serum half-life of TCDD for women and children. We also observed an increase in the percentage of female newborns to parents who resided in Zone A at the time of the explosion, and we also report on the 1976 serum dioxin levels in people who later developed cancer.

Paternal concentrations of dioxin and sex ratio of offspring

BACKGROUND

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD or dioxin), is commonly considered the most toxic man-made substance. We have previously shown that high serum concentrations of TCDD in parents from Seveso, Italy, were linked to their having a relative increase in the number of female births after the parents exposure to a release of dioxin in 1976. We have continued the study to determine whether the parents' sex and/or age at exposure affected the sex ratio of their children.

METHODS

We measured the TCDD concentrations in serum samples from potentially exposed parents collected in 1976 and 1977, and investigated the sex ratio of their offspring.

FINDINGS

Serum samples were collected from 239 men and 296 women. 346 girls and 328 boys were born to potentially exposed parents between 1977 and 1996, showing an increased probability of female births (lower sex ratio) with increasing TCDD concentrations in the serum samples from the fathers (p=0.008). This effect starts at concentrations less than 20 ng per kg bodyweight. Fathers exposed when they were younger than 19 years of age sired significantly more girls than boys (sex ratio 0.38 [95% CI 0.30-0.47]).

INTERPRETATION

Exposure of men to TCDD is linked to a lowered male/female sex ratio in their offspring, which may persist for years after exposure. The median concentration of dioxin in fathers in this study is similar to doses that induce epididymal impairments in rats and is about 20 times the estimated average concentration of TCDD currently found in human beings in industrialised countries. These observations could have important public-health implications.

[Vaccine prophylaxis: contribution for the control of biologic risk in exposed workers]

Working activities with exposure to biological agents have become a matter of discussion especially after the introduction in Italy of the Law 626/94, in conformity with the EU directive 90/679/EEC. There are many important biological agents that can have infectious, allergic, toxic or carcinogenic effects on the working population. Large occupational groups are exposed to these biohazards, both in agriculture and industry. Vaccination is one of the most beneficial medical practices, which has led to the eradication of such a devastating human disease as smallpox and the almost total elimination of poliomyelitis. Vaccination is also one of the most cost effective prevention measures applicable in this respect. This paper describes the possible vaccinations that employers should make available to employees exposed to biological risk, according to article 86 of Law 626/94.

Intrathymic restriction and peripheral expansion of the T-cell repertoire in Omenn syndrome

Mutations in the human RAG genes that impair, but do not abolish, recombination activity lead to Omenn syndrome, a severe primary immune deficiency that is associated with clinical and pathological features of graft-versus-host disease and oligoclonal expansion of activated, autologous T cells. We have analyzed the mechanisms accounting for peripheral oligoclonality of the T-cell repertoire. Predominance of few T-cell receptor clonotypes (both within TCRAB- and within TCRGD-expressing lymphocytes) is already detectable in the thymus and is further selected for in the periphery, with a different distribution of clonotypes in different tissues. These data indicate that oligoclonality of the T-cell repertoire in Omenn syndrome is due both to intrathymic restriction and to peripheral expansion. Moreover, the RAG genes defect that causes Omenn syndrome directly affects early stages of V(D)J recombination, but does not alter the process of double-strand-break DNA repair, including N and P nucleotide insertion.

Detection of identical T-cell clonotype expansions in both the donor and recipient after allogeneic bone marrow transplantation

Using phenotypic, functional and molecular techniques, this study was performed to compare the complexity of the T-cell receptor repertoire of a bone marrow transplanted patient with that of his HLA-matched related donor, both of whom developed a chronic lymphocytosis sustained by CD3+CD8+CD57+CD16-CD56- granular lymphocytes 3 years after transplantation. Although Southern blot analysis revealed the presence of extra bands in both subjects, thus indicating the presence of at least one clonal T-cell population, the study of the different T-cell receptor Vbeta (TCRBV) usage did not demonstrate discrete overexpression of any TCRBV segments. On the contrary, heteroduplex analysis of TCRBV transcripts suggested the presence of oligoclonal T-cell expansions in the two subjects. Cloning and sequencing studies demonstrated that T-cell clones expressing identical TCRBV chains were expanded both in the donor and in the recipient. Furthermore, clones with similar, but not identical, junctional regions were also found in the two subjects. These data indicate that, at the time of the graft, a few cells with a monoclonal/oligoclonal pattern that were present in the donor were transferred to the recipient, where they may have found the same environmental in vivo conditions and/or the antigenic pressure favouring their abnormal expansion.

Cytochrome P450 1B1 mRNA measured in blood mononuclear cells by quantitative reverse transcription-PCR

Cytochrome P450 (CYP) 1B1 activates polycyclic aromatic hydrocarbons and aryl aromatic hydrocarbons to carcinogens. We describe a competitive reverse transcription-PCR (RT-PCR) assay for the quantification of CYP1B1 mRNA in blood mononuclear cells (BMCs) by simultaneous RT and PCR amplification of cellular RNA with decreasing amounts of an internal standard. The concentration of CYP1B1 mRNA is derived from the ratio between the intensities of the bands corresponding to the amplified products. To reduce the variability of mRNA extraction efficiency, the measured amount of CYP1B1 has been calculated in relation to the β-actin gene products. We measured CYP1B1 expression in the BMCs of 75 human subjects; no significant differences in the CYP1B1:β-actin ratio were detected between women (range, 0.47–4.35; median, 2.0) and men (range, 0.72–3.85; median, 2.09). The analytical imprecision (CV) of duplicates was 14% (n = 25 pairs), and the intraindividual CV for two samples, 1 month apart, was 22% (n = 20). No significant differences were detected in smokers (n = 25; range, 0.77–3.55; median, 2.14) compared with nonsmokers (n = 50; range, 0.47–4.35; median, 2.0). The method has a wide range of linearity, good sensitivity and precision, and is suitable for studies of individual susceptibility as indicated by CYP1B1 expression in BMCs.

Cytochrome P450 1B1 mRNA measured in blood mononuclear cells by quantitative reverse transcription-PCR

Cytochrome P450 (CYP) 1B1 activates polycyclic aromatic hydrocarbons and aryl aromatic hydrocarbons to carcinogens. We describe a competitive reverse transcription-PCR (RT-PCR) assay for the quantification of CYP1B1 mRNA in blood mononuclear cells (BMCs) by simultaneous RT and PCR amplification of cellular RNA with decreasing amounts of an internal standard. The concentration of CYP1B1 mRNA is derived from the ratio between the intensities of the bands corresponding to the amplified products. To reduce the variability of mRNA extraction efficiency, the measured amount of CYP1B1 has been calculated in relation to the beta-actin gene products. We measured CYP1B1 expression in the BMCs of 75 human subjects; no significant differences in the CYP1B1:beta-actin ratio were detected between women (range, 0.47-4.35; median, 2.0) and men (range, 0.72-3.85; median, 2.09). The analytical imprecision (CV) of duplicates was 14% (n = 25 pairs), and the intraindividual CV for two samples, 1 month apart, was 22% (n = 20). No significant differences were detected in smokers (n = 25; range, 0.77-3.55; median, 2.14) compared with nonsmokers (n = 50; range, 0.47-4.35; median, 2.0). The method has a wide range of linearity, good sensitivity and precision, and is suitable for studies of individual susceptibility as indicated by CYP1B1 expression in BMCs.