Variation in PTX3 is associated with primary graft dysfunction after lung transplantation

RATIONALE

Elevated long pentraxin-3 (PTX3) levels are associated with the development of primary graft dysfunction (PGD) after lung transplantation. Abnormalities in innate immunity, mediated by PTX3 release, may play a role in PGD pathogenesis.

OBJECTIVES

Our goal was to test whether variants in the gene encoding PTX3 are risk factors for PGD.

METHODS

We performed a candidate gene association study in recipients from the multicenter, prospective Lung Transplant Outcomes Group cohort enrolled between July 2002 and July 2009. The primary outcome was International Society for Heart and Lung Transplantation grade 3 PGD within 72 hours of transplantation. Targeted genotyping of 10 haplotype-tagging PTX3 single-nucleotide polymorphisms (SNPs) was performed in lung transplant recipients. The association between PGD and each SNP was evaluated by logistic regression, adjusting for pretransplantation lung disease, cardiopulmonary bypass use, and population stratification. The association between SNPs and plasma PTX3 levels was tested across genotypes in a subset of recipients with idiopathic pulmonary fibrosis.

MEASUREMENTS AND MAIN RESULTS

Six hundred fifty-four lung transplant recipients were included. The incidence of PGD was 29%. Two linked 5' region variants, rs2120243 and rs2305619, were associated with PGD (odds ratio, 1.5; 95% confidence interval, 1.1 to 1.9; P = 0.006 and odds ratio, 1.4; 95% confidence interval, 1.1 to 1.9; P = 0.007, respectively). The minor allele of rs2305619 was significantly associated with higher plasma PTX3 levels measured pretransplantation (P = 0.014) and at 24 hours (P = 0.047) after transplantation in patients with idiopathic pulmonary fibrosis.

CONCLUSIONS

Genetic variants of PTX3 are associated with PGD after lung transplantation, and are associated with increased PTX3 plasma levels.

Elevated plasma long pentraxin-3 levels and primary graft dysfunction after lung transplantation for idiopathic pulmonary fibrosis

Primary graft dysfunction (PGD) after lung transplantation may result from ischemia reperfusion injury (IRI). The innate immune response to IRI may be mediated by Toll-like receptor and IL-1-induced long pentraxin-3 (PTX3) release. We hypothesized that elevated PTX3 levels were associated with PGD. We performed a nested case control study of lung transplant recipients with idiopathic pulmonary fibrosis (IPF) or chronic obstructive pulmonary disease (COPD) from the Lung Transplant Outcomes Group cohort. PTX3 levels were measured pretransplant, and 6 and 24 h postreperfusion. Cases were subjects with grade 3 PGD within 72 h of transplantation and controls were those without grade 3 PGD. Generalized estimating equations and multivariable logistic regression were used for analysis. We selected 40 PGD cases and 79 non-PGD controls. Plasma PTX3 level was associated with PGD in IPF but not COPD recipients (p for interaction < 0.03). Among patients with IPF, PTX3 levels at 6 and 24 h were associated with PGD (OR = 1.6, p = 0.02 at 6 h; OR = 1.4, p = 0.008 at 24 h). Elevated PTX3 levels were associated with the development of PGD after lung transplantation in IPF patients. Future studies evaluating the role of innate immune activation in IPF and PGD are warranted.

Salvaging the dehisced lung transplant bronchial anastomosis with homograft aorta

This is a case of 50-year-old male who underwent left single lung transplantation for pulmonary fibrosis. He sustained a bronchial dehiscence with a pulmonary artery-bronchial fistula which was primarily repaired. One week later, there was complete bronchial dehiscence followed by a massive hemoptysis. At operation, following resection of necrotic donor bronchus there was a sizeable gap between donor and recipient bronchus, which was bridged with a cryopreserved aortic homograft. The homograft patch provided a satisfactory repair without malacia. The patient required retransplantation six months later for reasons unassociated with the repair. Homograft aorta proved useful material for salvaging the dehisced lung transplant bronchial anastomosis.

Elevated plasma clara cell secretory protein concentration is associated with high-grade primary graft dysfunction

Primary graft dysfunction (PGD) is the leading cause of early posttransplant morbidity and mortality after lung transplantation. Clara cell secretory protein (CC16) is produced by the nonciliated lung epithelium and may serve as a plasma marker of epithelial cell injury. We hypothesized that elevated levels of CC16 would be associated with increased odds of PGD. We performed a prospective cohort study of 104 lung transplant recipients. Median plasma CC16 levels were determined at three time points: pretransplant and 6 and 24 h posttransplant. The primary outcome was the development of grade 3 PGD within the first 72 h after transplantation. Multivariable logistic regression was performed to evaluate for confounding by donor and recipient demographics and surgical characteristics. Twenty-nine patients (28%) developed grade 3 PGD within the first 72 h. The median CC16 level 6 h after transplant was significantly higher in patients with PGD [13.8 ng/mL (IQR 7.9, 30.4 ng/mL)] than in patients without PGD [8.2 ng/mL (IQR 4.5, 19.1 ng/mL)], p = 0.02. Elevated CC16 levels were associated with increased odds of PGD after lung transplantation. Damage to airway epithelium or altered alveolar permeability as a result of lung ischemia and reperfusion may explain this association.

Effect of single vs bilateral lung transplantation on plasma surfactant protein D levels in idiopathic pulmonary fibrosis

BACKGROUND

Serum levels of surfactant protein D (SP-D) have been suggested as reflecting epithelial damage in acute lung injury, COPD, and idiopathic pulmonary fibrosis (IPF). However, little is known about SP-D levels in the setting of lung transplantation.

METHODS

We examined plasma SP-D levels in 104 subjects from a prospective, multicenter cohort study of lung allograft recipients. Plasma SP-D was measured by enzyme-linked immunosorbent assay prior to transplant and daily for 3 days after transplant.

RESULTS

Subjects undergoing transplant for IPF had higher baseline SP-D levels (median, 325 ng/mL) compared with subjects with cystic fibrosis, COPD, and pulmonary hypertension (median, 100, 80, and 82 ng/mL, respectively; P = .0001). Among subjects with IPF undergoing bilateral transplant, SP-D levels declined rapidly postoperatively. In contrast, SP-D levels in subjects undergoing single lung transplant for IPF remained significantly higher than those of bilateral allograft recipients. Among subjects undergoing single lung transplant for IPF, the development of primary graft dysfunction (PGD) was associated with a subsequent rise in SP-D levels, whereas SP-D levels in IPF subjects undergoing bilateral transplant declined, even in the presence of grade 3 PGD. Importantly, single lung allograft recipients without PGD had higher postoperative SP-D levels than bilateral allograft recipients with PGD.

CONCLUSIONS

Subjects undergoing lung transplant for IPF have significantly higher baseline plasma SP-D levels compared with those with other diagnoses. Plasma SP-D is likely a biomarker of the air-blood barrier integrity in the native IPF lung, but may be less useful as a biomarker of PGD after transplant.

Elevated pulmonary artery pressure is a risk factor for primary graft dysfunction following lung transplantation for idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is often associated with elevations in pulmonary artery pressures. Although primary pulmonary arterial hypertension (PAH) has been associated with primary graft dysfunction (PGD), the role of secondary PAH in mediating PGD risk in patients with IPF is incompletely understood. The purpose of this study was to evaluate the relationship between mean pulmonary artery pressure (mPAP) and PGD among patients with IPF.

METHODS

We performed a multicenter prospective cohort study of 126 lung transplant procedures performed for IPF between March 2002 and August 2007. The primary outcome was grade 3 PGD at 72 h after lung transplant. The mPAP was measured as the initial reading following insertion of the right-sided heart catheter during lung transplant. Multivariable logistic regression was used to adjust for confounding variables.

RESULTS

The mPAP for patients with PGD was 38.5 ± 16.3 mm Hg vs 29.6 ± 11.5 mm Hg for patients without PGD (mean difference, 8.9 mm Hg [95% CI, 3.6-14.2]; P = .001). The increase in odds of PGD associated with each 10-mm Hg increase in mPAP was 1.64 (95% CI, 1.18-2.26; P = .003). In multivariable models, this relationship was independent of confounding by other clinical variables, although the use of cardiopulmonary bypass partially attenuated the relationship.

CONCLUSIONS

Higher mPAP in patients with IPF is associated with the development of PGD.

The state of the art of residue analysis: the 6th VDRA symposium 2010

Since the onset of residue analysis (ca 40 years ago) a lot of attention has been paid to the amelioration of analytical methods, for example, lowering the limits of detection (LOD) and limits of quantification (LOQ) or decision limits (CCα) and detection capabilities (CCβ), including an increase in the number of analytes, shortening runtimes, increasing sample throughput, amongst others. The state of the art in residue analysis, which was presented at the VDRA 2010 symposium (Hormone and Veterinary Drug Residue Analysis) in Ghent is reviewed in this article. From an analytical point of view, the use of ultra high performance liquid chromatography (UHPLC) hyphenated with accurate mass spectrometry is often used in combination with other (biological) detection systems and 'omic' approaches. Through these techniques more xenobiotic substances turn out to be naturally occurring in some matrices and/or circumstances (e.g. thiouracil, chloramphenicol and semicarbazide).

Construct validity of the definition of primary graft dysfunction after lung transplantation

BACKGROUND

This study tested the discriminant validity of International Society for Heart and Lung Transplantation (ISHLT) primary graft dysfunction (PGD) grades with lung injury biomarker profiles and survival.

METHODS

The study samples consisted of a multicenter prospective cohort study for the biomarker analysis and a cohort study of 450 patients for the mortality analyses. PGD was defined according to ISHLT consensus at 24, 48, and 72 hours after transplantation. We compared the changes in plasma markers of acute lung injury between PGD grades using longitudinal data models. To test predictive validity, we compared differences in the 30-day mortality and long-term survival according to PGD grade.

RESULTS

PGD Grade 3 demonstrated greater differences between plasma intercellular adhesion molecule 1 (ICAM-1), protein C, and plasminogen activator inhibitor type 1 (PAI-1) levels than did PGD Grades 0 to 2 at 24, 48, and 72 hours after lung transplantation (p < 0.05 for each). Grade 3 had the highest 30-day (test for trend p < 0.001) and overall mortality (log rank p < 0.001), with PGD Grades 1 and 2 demonstrating intermediate risks of mortality. The ability to discriminate both 30-day and overall mortality improved as the time of grading moved away from the time of transplantation (test for trend p < 0.001).

CONCLUSIONS

The ISHLT grading system has good discriminant validity, based on plasma markers of lung injury and mortality. Grade 3 PGD was associated with the most severely altered plasma biomarker profile and the worst outcomes, regardless of the time point of grading. PGD grade at 48 and 72 hours discriminated mortality better than PGD grade at 24 hours.

A validated analytical method for the determination of perfluorinated compounds in surface-, sea- and sewagewater using liquid chromatography coupled to time-of-flight mass spectrometry

Perfluorinated compounds (PFCs), which are extensively used in a wide variety of applications because of their specific surfactant properties, have recently appeared as an important new class of global environmental pollutants. Quantitative analysis of PFCs in aqueous matrices remains, however, a challenging task. During this study, a new analytical method for the determination of 14 PFCs in surface-, sewage- and seawater was developed and validated. The target analytes were extracted using solid-phase extraction followed by liquid chromatography coupled to a time-of-flight mass spectrometer (LC-ToF-MS). The use of very narrow mass tolerance windows (< 10 ppm) resulted in a highly selective MS-technique for the detection of PFCs in complex aqueous matrices. Validation of this analytical method in surface-, sewage- and seawater resulted in limits of quantification (LOQs) varying from 2 to 200 ng L⁻¹, satisfying recoveries (92-134%), and good linearity (R²=0.99 for most analytes). Analysis of samples of the North Sea, the Scheldt estuary, and three harbours of the Belgian coastal region led to the detection of four different PFCs. Perfluorooctane sulfonate (PFOS) was found to be the most abundant PFC in levels up to 38.9 ng L⁻¹.

Endogenous boldenone-formation in cattle: alternative invertebrate organisms to elucidate the enzymatic pathway and the potential role of edible fungi on cattle's feed

Although beta-boldenone (bBol) used to be a marker of illegal steroid administration in calves, its endogenous formation has recently been demonstrated in these vertebrates. However, research on the pathway leading to bBol remains scarce. This study shows the usefulness of in vivo invertebrate models as alternatives to vertebrate animal experiments, using Neomysis integer and Lucilia sericata. In accordance with vertebrates, androstenedione (AED) was the main metabolite of beta-testosterone (bT) produced by these invertebrates, and bBol was also frequently detected. Moreover, in vitro experiments using feed-borne fungi and microsomes were useful to perform the pathway from bT to bBol. Even the conversion of phytosterols into steroids was shown in vitro. Both in vivo and in vitro, the conversion of bT into bBol could be demonstrated in this study. Metabolism of phytosterols by feed-borne fungi may be of particular importance to explain the endogenous bBol-formation by cattle. To the best of our knowledge, it is the first time the latter pathway is described in literature.

Characterisation of steroids in wooden crates of veal calves by accelerated solvent extraction (ASE) and ultra-high performance liquid chromatography coupled to triple quadrupole mass spectrometry (U-HPLC-QqQ-MS-MS)

Illegal steroid administration to enhance growth performance in veal calves has long been, and still is, a serious issue facing regulatory agencies. Over the last years, stating undisputable markers of illegal treatment has become complex because of the endogenous origin of several anabolic steroids. Knowledge on the origin of an analyte is therefore of paramount importance. The present study shows the presence of steroid analytes in wooden crates used for housing veal calves. For this purpose, an analytical procedure using accelerated solvent extraction (ASE(R)), solid-phase extraction (SPE) and ultra-high performance liquid chromatography coupled to triple quadrupole mass spectrometry (U-HPLC-MS-MS) is developed for the characterisation of androstadienedione (ADD), boldenone (bBol), androstenedione (AED), beta-testosterone (bT), alpha-testosterone (aT), progesterone (P) and 17alpha-hydroxy-progesterone (OH-P) in wood samples. In samples of wooden crates used for housing veal calves, ADD, AED, aT and P could be identified. Using the standard addition approach concentrations of these analytes were determined ranging from 20 +/- 4 ppb to 32 +/- 4 ppb for ADD, from 19 +/- 5 ppb to 44 +/- 17 ppb for AED, from 11 +/- 6 ppb to 30 +/- 2 ppb for aT and from 14 +/- 1 ppb to 42 +/- 27 ppb for P, depending on the sample type. As exposure of veal calves to steroid hormones in their housing facilities might complicate decision-making on illegal hormone administration, inequitable slaughter of animals remains possible. Therefore, complete prohibition of wooden calf accommodation should be considered.

Plasma levels of receptor for advanced glycation end products, blood transfusion, and risk of primary graft dysfunction

RATIONALE

The receptor for advanced glycation end products (RAGE) is an important marker of lung epithelial injury and may be associated with impaired alveolar fluid clearance. We hypothesized that patients with primary graft dysfunction (PGD) after lung transplantation would have higher RAGE levels in plasma than patients without PGD.

OBJECTIVES

To test the association of soluble RAGE (sRAGE) levels with PGD in a prospective, multicenter cohort study.

METHODS

We measured plasma levels of sRAGE at 6 and 24 hours after allograft reperfusion in 317 lung transplant recipients at seven centers. The primary outcome was grade 3 PGD (Pa(O(2))/Fi(O(2)) < 200 with alveolar infiltrates) within the first 72 hours after transplantation.

MEASUREMENTS AND MAIN RESULTS

Patients who developed PGD had higher levels of sRAGE than patients without PGD at both 6 hours (median 9.3 ng/ml vs. 7.5 ng/ml, respectively; P = 0.028) and at 24 hours post-transplantation (median 4.3 ng/ml vs. 1.9 ng/ml, respectively; P < 0.001). Multivariable logistic regression analyses indicated that the relationship between levels of sRAGE and PGD was attenuated by elevated right heart pressures and by the use of cardiopulmonary bypass. Median sRAGE levels were higher in subjects with cardiopulmonary bypass at both 6 hours (P = 0.003) and 24 hours (P < 0.001). sRAGE levels at 6 hours were significantly associated with intraoperative red cell transfusion (Spearman's rho = 0.39, P = 0.002 in those with PGD), and in multivariable linear regression analyses this association was independent of confounding variables (P = 0.02).

CONCLUSIONS

Elevated plasma levels of sRAGE are associated with PGD after lung transplantation. Furthermore, plasma sRAGE levels are associated with blood product transfusion and use of cardiopulmonary bypass.

Plasma cytokines and chemokines in primary graft dysfunction post-lung transplantation

Primary graft dysfunction (PGD) after lung transplantation causes significant morbidity and mortality. We aimed to determine the role of cytokines and chemokines in PGD. This is a multicenter case-control study of PGD in humans. A Luminex analysis was performed to determine plasma levels of 25 chemokines and cytokines before and at 6, 24, 48 and 72 h following allograft reperfusion in 25 cases (grade 3 PGD) and 25 controls (grade 0 PGD). Biomarker profiles were evaluated using a multivariable logistic regression and generalized estimating equations. PGD cases had higher levels of monocyte chemotactic protein-1 (MCP-1)/chemokine CC motif ligand 2 (CCL2) and interferon (IFN)-inducible protein (IP-10)/chemokine CXC motif ligand 10 (CXCL10) (both p < 0.05), suggesting recruitment of monocytes and effector T cells in PGD. In addition, PGD cases had lower levels of interleukin (IL-13) (p = 0.05) and higher levels of IL-2R (p = 0.05). Proinflammatory cytokines, including tumor necrosis factor (TNF)-alpha, and IFN-gamma decreased to very low levels after transplant in both PGD cases and controls, exhibiting no differences between the two groups. These findings were independent of clinical variables including diagnosis in multivariable analyses, but may be affected by cardiopulmonary bypass. Profound injury in clinical PGD is distinguished by the upregulation of selected chemokine pathways, which may useful for the prediction or early detection of PGD if confirmed in future studies.

Analysis of thyreostats: a history of 35 years

Thyreostatic drugs (TS), illegally administrated to livestock for fattening purposes, are banned in the European Union since 1981 (Council Directive 81/602/EC). This paper reviews the trends in the analytical approaches for the determination of TS drugs in biological matrices. After a brief introduction on the different groups of compounds with a thyreostatic action, the most relevant legislation regarding the residue control of these compounds is presented. An overview of the analytical possibilities for the determination of TS in animal matrices, covering sample extraction, purification, separation techniques and detection methods is provided. Additionally, a brief outline of animal experiments is described that illustrates the excretion and distribution profiles of TS residues. Finally, the novel developments in TS analysis are highlighted. Also the possible semi-endogenous status of thiouracil is discussed.

Plasma intercellular adhesion molecule-1 and von Willebrand factor in primary graft dysfunction after lung transplantation

Primary graft dysfunction (PGD), a form of acute lung injury occurring within 72 h following lung transplantation, is characterized by pulmonary edema and diffuse alveolar damage. We hypothesized that higher concentrations of intercellular adhesion molecule-1 (ICAM-1) and von Willebrand factor (vWF) would be associated with the occurrence of PGD. A total of 128 lung transplant recipients among 7 lung transplant centers were enrolled in a multicenter, prospective, cohort study. Blood specimens were collected preoperatively and at 6, 24, 48 and 72 h following lung transplantation. The primary outcome was Grade 3 PGD at 72 h after transplant. Logistic regression and generalized estimating equations (GEE) were used to analyze plasma ICAM-1 and vWF. At each postoperative timepoint, mean plasma ICAM-1 concentrations were higher for patients with PGD versus no PGD. The GEE contrast estimate for the association of plasma ICAM-1 with PGD was 107.5 ng/mL (95% CI 38.7, 176.3), p = 0.002. In the multivariate analyses, this finding was independent of all clinical variables except pulmonary artery pressures prior to transplant. There was no association between plasma vWF levels and PGD. We conclude that higher levels of plasma ICAM-1 are associated with PGD following lung transplantation.

Multi-organ transplantation: is there a protective effect against acute and chronic rejection?

BACKGROUND

Heart-lung transplantation (Tx) is known to offer a protective effect against acute cardiac rejection. This study was undertaken to evaluate acute and chronic heart and/or lung rejection in the setting of multiple-transplanted organs from the same donor compared with single-organ transplantation.

METHODS

Acute (treated rejection episodes of heart or lungs) and chronic (allograft vasculopathy in hearts and bronchiolitis obliterans syndrome [BOS] in lungs) rejection events were analyzed in 348 heart transplant (H) recipients, 24 heart-lung (HL) recipients, 82 double-lung (L) recipients and 8 heart-kidney (HK) recipients >18 years of age, who were transplanted between 1990 and 2002.

RESULTS

Survival at 3 years differed among groups as follows: HK, 100%; H, 82%; HL, 74%; and L, 70%. The probability of acute rejection within the first 3 months was higher in H recipients than in HL (81% vs 22%; p < 0.0001) or HK (81% vs 12%; p = 0.00009) recipients. Acute cardiac rejection occurred more frequently during the first 2 years in isolated H recipients compared with HL (2.8 vs 0.27 episodes; p < 0.0001) and HK (2.8 vs 0.54; p < 0.001) recipients. Acute lung rejection occurred more frequently in the first 2 years in L than HL (2.4 vs 1.0 episodes; p = 0.02) recipients. Chronic cardiac rejection (allograft vasculopathy) was more likely within 3 years after H compared with HL (32% vs 16%; p = 0.04) or HK (32% vs 0%; p = 0.14). The onset of chronic lung rejection (BOS) within 3 years was similar in HL and L recipients (39% vs 40%; p = 0.9).

CONCLUSIONS

Recipients of multiple organs from a single donor undergo less acute rejection of the heart or lungs compared with isolated heart or lung transplant recipients. Cardiac allograft vasculopathy is decreased significantly when cardiac transplantation is combined with a lung allograft. A lower incidence of cardiac allograft vasculopathy is observed when cardiac transplantation is combined with a renal allograft, and may prove statistically significant when more cases have been accumulated. These phenomena may result from immune modulation of the recipient by simultaneous transplant of disparate tissues or introduction of immune-modulating hematopoietic elements.

Validation of a multistage asthma case-detection procedure for elementary school children

OBJECTIVE

The purpose of this study was to validate a 3-stage asthma case-detection procedure for elementary school-aged children.

METHODS

The study was performed in 10 elementary schools in 4 inner-city school systems, with a total enrollment of 3539 children. Results of the case-detection procedure were compared with the diagnosis of an asthma specialist study physician, to determine the sensitivity and specificity of the case-detection procedure.

RESULTS

Ninety-eight percent of children returned the asthma symptoms questionnaires, and 79% of those children consented to additional testing. Results indicated that the 3-stage procedure had good validity, with sensitivity, specificity, and predictive value of 82%, 93%, and 93%, respectively. A 2-stage procedure using questionnaires and spirometry had similar validity, with sensitivity, specificity, and predictive value of 78%, 93%, and 93%, respectively. However, given the time and expense associated with the 2- or 3-stage procedure and the difficulty of obtaining physician follow-up evaluation of the case-detection diagnosis, schools may prefer to use a 2-item questionnaire that has a lower sensitivity (66%) but higher specificity (96%) and predictive value (95%).

CONCLUSIONS

Case-detection programs are generally well received by school personnel and can identify children with unrecognized or undiagnosed disease, as well as those with a current diagnosis but poorly controlled disease. This study yields substantial information regarding the validity, yield, and specific types of children who might be identified with the use of such procedures. For the choice of the method of case detection used in a school, the strengths and weaknesses of each procedure, as well as the resources available for case detection, physician referral, and follow-up procedures, must be considered.

Induction of P-450 in workers exposed to dioxin

OBJECTIVES

To examine the effects of occupational exposure to substances contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on cytochrome P-4501A2 activity in a cross sectional medical survey.

METHODS

The exposed workers had been employed at two chemical plants > 15 years earlier in the manufacture of 2,4, 5-trichlorophenol and its derivatives. The control group consisted of people with no occupational exposure to phenoxy herbicides and who lived within the communities of the exposed workers. A total of 58 workers and 125 unexposed controls participated in the analysis. Cytochrome P-450 activity was assessed with test that measures caffeine metabolites in the urine. A ratio of metabolites of caffeine (CMR) constituted a measure of P-4501A2 activity.

RESULTS

Compared with the control group in multivariate logistic regression, raised non-significant associations were found for three of four categories of TCDD in exposed workers (TCDD < 20 pg/g, odds ratio (OR) 1.7, 95% confidence interval (95% CI) 0.6 to 5.0, TCDD 20-66, OR 0.3, 95% CI 0.0 to 1.7; TCDD 67-147, OR 2.3, 95% CI 0.6 to 8.8; TCDD > or = 148, OR 3.1, 95% CI 0.8 to 12.5). We found a strongly significant association of CMR and urinary cotinine, a measure of smoking, and urinary free ethanol. We found weak non-significant associations between P-4501A2 activity and increased serum TCDD among workers.

CONCLUSIONS

The absence of an association between serum TCDD and cytochrome P-4501A2 may be due to the size of the study, insensitivity of the CMR to assess cytochrome P-4501A2 activity, or inadequate levels of exposure, although these were among the highest in human groups tested.