bluuebunny/crossref_metadata_2025 huggingface dataset:
Airway symptoms and lung function in pipelayers exposed to thermal degradation products from MDI-based polyurethane.
Authors: Jakobsson K , Kronholm-Diab K , Rylander L , Hagmar L
Published: December 2008

OBJECTIVES: To study the prevalence of symptoms from the eyes and the upper and lower respiratory tract, lung function, and immunological sensitisation towards isocyanates in pipelayers exposed to thermal degradation products from methylene diphenyl diisocyanate (MDI)-based polyurethane (PUR). MATERIAL AND METHODS: 50 presently active and 113 formerly active pipelayers were examined. Also, 65 unexposed workers were investigated for comparison. The one year prevalence of symptoms and smoking history (questionnaire data), lung function (vital capacity (VC) and forced expiratory volume in one second (FEV1), and atopy (positive skin prick tests towards standard allergens) were assessed among pipelayers and controls. For the pipelayers, the presence of work related symptoms and estimates of isocyanate and welding exposure were obtained from an interview. Skin prick tests towards specific isocyanate antigens and determinations of IgE-MDI and IgG-MDI in serum were also performed. RESULTS: The prevalence of episodes (more than once a month) of irritative eye symptoms, congestion of the nose, and soreness or dryness in the throat was much higher among the PUR pipelayers than among the controls. Most of the pipelayers with symptoms reported that these had started and occurred in relation to the PUR welding tasks. Presently active pipelayers with recent high PUR exposure showed a significant reduction of FEV1 compared with the controls. The estimated reduction, adjusted for smoking, was -0.3 l (P = 0.04). There was no confounding effect of ordinary welding. None of the pipelayers showed positive skin prick reactions against the specific isocyanate antigens used, or positive IgE-MDI, and only two had increased IgG-MDI. CONCLUSIONS: The findings indicate that exposure to thermal degradation products from MDI-based polyurethane has adverse effects on the mucous membranes and airways.
Congenital malformations and maternal occupation: a registry based case-control study.
Authors: Bianchi F , Cianciulli D , Pierini A , Seniori Costantini A
Published: December 2008

OBJECTIVES: To investigate the relations between congenital malformations and maternal occupation during pregnancy with a registry based case-control study. METHODS: Analysis was performed on data derived from the Florence Eurocat registry surveillance programme. The study included cases with isolated conditions, including chromosomal anomalies (n = 1351), cases with multiple anomalies registered during the 1980-91 period (n = 440), and babies with no congenital malformations recognised at birth who were born from 1982 to 1989 and selected as controls (n = 3223). 11 categories were defined, 10 including cases with isolated malformations and one for cases with multiple congenital anomalies. Four categories of maternal occupation were selected for the study. Odds ratio (OR) values were adjusted for maternal origin, maternal and paternal education, number of previous live births, illness during pregnancy, and maternal age when the group of chromosomal anomalies was analysed. RESULTS: A notable and significant association between oral clefts and mothers involved in leather and shoe manufacturing was found (adjusted OR 3.9; 99% confidence interval (99% CI) 1.5 to 9.8) and the risk consistently increased when considering cases with isolated cleft palate separately (OR 5.4; 95% CI 1.8 to 13.4). Moreover, a significant risk was identified for the association between multiple anomalies and textile dye workers (adjusted OR 1.9; 99% CI 1.0 to 3.8). CONCLUSIONS: This study indicates a notable, significant relation between maternal occupation as a pelt or leather worker and orofacial clefts in offspring. This finding is in agreement with the suggested inheritance models. The dilution effect due to studying large and heterogeneous groups of workers and occupations limits the value of the study; but it provides a good example of the use of a large database to search for teratogenic risk with the aid of malformation registries.
delta-Aminolevulinic acid dehydratase genotype modifies four hour urinary lead excretion after oral administration of dimercaptosuccinic acid.
Authors: Schwartz B S , Lee B K , Stewart W , Sithisarankul P , Strickland P T , Ahn K D , Kelsey K
Published: December 2008

OBJECTIVES: Previous research suggests that binding of lead by delta-aminolevulinic acid dehydratase (ALAD) may vary by ALAD genotype. This hypothesis was tested by examining whether ALAD genotype modifies urinary lead excretion (DMSA chelatable lead) after oral administration of dimercaptosuccinic acid (DMSA). METHODS: 57 South Korean lead battery manufacturing workers were given 5 mg/kg oral DMSA and urine was collected for four hours. Male workers were randomly selected from two ALAD genotype strata (ALAD1-1, ALAD1-2) from among all current workers in the two plants (n = 290). Subjects with ALAD1-1 (n = 38) were frequency matched with subjects with ALAD1-2 (n = 19) on duration of employment in the lead industry. Blood lead, zinc protoporphyrin, and plasma aminolevulinic acid concentrations, as well as ALAD genotype, duration of exposure, current tobacco use, and weight were examined as predictors or effect modifiers of levels of DMSA chelatable lead. RESULTS: Blood lead concentrations ranged from 11 to 53 micrograms/dl, with a mean (SD) of 25.4 (10.2) micrograms/dl. After 5 mg/kg DMSA orally, the workers excreted a mean (SD) 85.4 (45.0) micrograms lead during a four hour urine collection (range 16.5-184.1 micrograms). After controlling for blood lead concentrations, duration of exposure, current tobacco use, and body weight, subjects with ALAD1-2 excreted, on average, 24 micrograms less lead during the four hour urine collection than did subjects with ALAD1-1 (P = 0.05). ALAD genotype seemed to modify the relation between plasma delta-aminolevulinic acid (ALA) and DMSA chelatable lead. Workers with ALAD1-2 excreted more lead, after being given DMSA, with increasing plasma ALA than did workers with ALAD1-1 (P value for interaction = 0.01). CONCLUSIONS: DMSA chelatable lead may partly reflect the stores of bioavailable lead, and the current data indicate that subjects with ALAD1-2 have lower stores than those with ALAD1-1. These data provide further evidence that the ALAD genotype modifies the toxicokinetics of lead-for example, by differential binding of current lead stores or by differences in long-term retention and deposition of lead.
Correlation between 99Tcm-HMPAO-SPECT brain image and a history of decompression illness or extent of diving experience in commercial divers.
Authors: Shields T G , Duff P M , Evans S A , Gemmell H G , Sharp P F , Smith F W , Staff R T , Wilcock S E
Published: December 2008

OBJECTIVES: To explore the use of 99technetiumm-hexamethyl propylene amine oxime single photon computed tomography (HMPAO-SPECT) of the brain as a means of detecting nervous tissue damage in divers and to determine if there is any correlation between brain image and a diver's history of diving or decompression illness (DCI). METHODS: 28 commercial divers with a history of DCI, 26 divers with no history of DCI, and 19 non-diving controls were examined with brain HMPAO-SPECT. Results were classified by observer assessment as normal (I) or as a pattern variants (II-V). The brain images of a subgroup of these divers (n = 44) and the controls (n = 17) were further analysed with a first order texture analysis technique based on a grey level histogram. RESULTS: 15 of 54 commercial divers (28%) were visually assessed as having HMPAO-SPECT images outside normal limits compared with 15.8% in appropriately identified non-diver control subjects. 18% of divers with a history of DCI were classified as having a pattern different from the normal image compared with 38% with no history of DCI. No association was established between the presence of a pattern variant from the normal image and history of DCI, diving, or other previous possible neurological insult. On texture analysis of the brain images, divers had a significantly lower mean grey level (MGL) than non-divers. Divers with a history of DCI (n = 22) had a significantly lower MGL when compared with divers with no history of DCI (n = 22). Divers with > 14 years professional diving or > 100 decompression days a year had a significantly lower MGL value. CONCLUSIONS: Observer assessment of HMPAO-SPECT brain images can lead to disparity in results. Texture analysis of the brain images supplies both an objective and consistent method of measurement. A significant correlation was found between a low measure of MGL and a history of DCI. There was also an indication that diving itself had an effect on texture measurement, implying that it had caused subclinical nervous tissue damage.
Episode of toxic gas exposure in sewer workers.
Authors: Watt M M , Watt S J , Seaton A
Published: December 2008

OBJECTIVES: Sewer workers are used to unpleasant smells, but may be required to investigate unusual ones. Twenty six men were involved in investigation of episodes of such a smell after neighbourhood complaints over several weeks. METHODS: Workers exposed to the smell were investigated by clinical follow up, lung function tests, and measurement of pituitary function. RESULTS: 14 of the 26 developed subacute symptoms including sore throat, cough, chest tightness, breathlessness, thirst, sweating, irritability, and loss of libido. Severity of symptoms seemed to be dose related. Minor symptoms resolved over several weeks but those more seriously affected have shown deteriorating respiratory symptoms and lung function and remain unable to work a year after the incident. In one, evidence of mild cranial diabetes insipidus was found. Analysis of gas from the sewer showed the presence of a mixture of thiols and sulphides, known to be highly odorous and not normally found in sewers. The source remains unknown. CONCLUSIONS: Several of these men seem to have developed delayed airways disease and disturbances of hypothalamic function. Such an outcome has not to our knowledge been described before. Despite the presence of the smell, standard safety gas detection equipment used to ensure the sewer was safe to enter failed to indicate the presence of a hazard. Protection against such incidents can only be provided by the use of positive pressure breathing apparatus.
Time to pregnancy: a measure of reproductive function in either sex. Asclepios Project.
Authors: Joffe M
Published: December 2008

INTRODUCTION: Growing evidence of reproductive effects associated with occupational and environmental agents has created the need for research with sensitive and well validated methods. There is a complex relation between manifest effects and underlying pathogenic processes. Conceptions will on average tend to be delayed in a population exposed to an agent that causes embryonic damage, an increase in germ cell mutations, or decreased fertility. STUDYING TIME TO PREGNANCY: Time to pregnancy can be used to measure the degree of delay in conceiving, across the whole continuum of biological fertility, in either men or women. The distribution of time to pregnancy largely reflects a sorting process, as the more fertile couples become progressively less well represented with the passage of time. The basic research strategy is comparison of the time to pregnancy within groups defined by their exposures, allowing for potential confounding factors relating not only to the study subject but also to his or her partner. MEASUREMENT AND VALIDITY: Prospective and retrospective methods are available, and each has strengths and weaknesses. Prospective studies have some theoretical advantages, but have unrepresentative populations and problems of feasibility and cost. Retrospective assessment of time to pregnancy is feasible with a short questionnaire, without intruding into sensitive areas of respondents' lives, with good validity at the group level, and without the necessity of large populations. Potential biases have been identified that can be minimised by careful design and analysis; the principal remaining problem is difficulty in obtaining exposure data retrospectively.
Occupational asthma in New Zealanders: a population based study.
Authors: Fishwick D , Pearce N , D'Souza W , Lewis S , Town I , Armstrong R , Kogevinas M , Crane J
Published: December 2008

OBJECTIVES: To examine the effect of occupation on respiratory symptoms in a randomly selected adult population aged 20-44 years. METHODS: It is based on the phase II sampling of the New Zealand part of the European Community respiratory health survey. 1609 people (63.9% response rate) completed a detailed respiratory questionnaire. Of those responding, 1174 (73%) underwent skin tests and 1126 (70%) attended to undergo methacholine bronchial challenge. Current occupation was recorded and a previous occupation was also recorded if it had led to respiratory problems. 21 occupational groups were used for analysis for the five definitions of asthma wheezing in the previous 12 months; symptoms related to asthma; bronchial hyperresponsiveness (BHR); BHR with wheezing in the previous 12 months; and BHR with symptoms related to asthma. RESULTS: Prevalence odds ratios (ORs) were significantly increased for farmers and farm workers (OR 4.16, 95% confidence interval (95% CI) 1.33 to 13.1 for the combination of wheezing and BHR). Increased risks of prevalence of asthma were also found for laboratory technicians, food processors (other than bakers), chemical workers, and plastic and rubber workers. Workers had also been divided into high and low risk exposure categories according to relevant publications. The prevalence of wheezing was greater in the high risk group (OR 1.57, 95% CI 0.83 to 2.95) than in the low risk group. Atopy was associated with asthma, but the prevalence of atopy did not differ significantly between occupational exposure groups. The attributable risk of wheezing that occurred after the age of 15 years and that was estimated to be due to occupational exposure (based on the defined high risk group) was 1.9%, but this increased to 3.1% when farmers and food processors (other than bakers) were also included in the high risk group. CONCLUSIONS: This population based study has identified certain occupations significantly associated with combinations of asthmatic symptoms and BHR.
In vivo analysis of cadmium in battery workers versus measurements of blood, urine, and workplace air.
Authors: Börjesson J , Bellander T , Järup L , Elinder C G , Mattsson S
Published: December 2008

OBJECTIVES: To measure in vivo the cadmium concentrations in kidney cortex (kidney-Cd) and in superficial liver tissue (liver-Cd) of nickel cadmium battery workers, and to compare the results with other commonly used estimates of cadmium exposure (current concentrations of cadmium in blood (B-Cd) and urine (U-Cd)) or repeated measurements of cadmium in workplace air (CumAir-Cd). METHODS: The study comprised 30 workers with a range of duration of exposure of 11-51 years. 13 subjects were currently employed, whereas the other 17 had a median period without occupational exposure of eight years before the measurements. The in vivo measurements were made with an x ray fluorescence technique permitting average detection limits of 30 and 3 micrograms cadmium per g tissue in kidney and liver, respectively. RESULTS: 19 of 30 (63%) people had kidney-Cd and 13 of 27 (48%) had liver-Cd above the detection limits. Kidney-Cd ranged from non-detectable to 350 micrograms/g and liver-Cd from non-detectable to 80 micrograms/g. The median kidney-Cd and liver-Cd were 55 micrograms/g and 3 micrograms/g, respectively. Kidney-Cd correlated significantly with B-Cd (r, 0.49) and U-Cd (r, 0.70), whereas liver-Cd correlated significantly with U-Cd (r, 0.58). Neither kidney-Cd nor liver-Cd correlated with the CumAir-Cd. The prevalence of beta 2-microglobulinurea increased with increased liver-Cd. CONCLUSIONS: Current U-Cd can be used to predict the kidney-Cd and liver-Cd measured in vivo. In vivo measurements of kidney-Cd and liver-Cd were not shown to correlate with the individual cadmium exposure estimates, obtained by integration of the cadmium concentration in workplace air. There may be several reasons for this, including uncertainties in the estimate of the individual cumulative exposures as well as in the in vivo measurements. There was a suggestion of a relation between liver-Cd and tubular proteinuria.
Contrast sensitivity measurement in evaluations of visual symptoms caused by exposure to triethylamine.
Authors: Järvinen P , Hyvärinen L
Published: December 2008

OBJECTIVES: To determine whether blurred vision caused by exposure to triethylamine (TEA) can be detected by the measurement of contrast sensitivity. METHODS: 41 cold box core makers of three foundries and 82 control workers were examined. A detailed ocular and medical history was obtained from the subjects. The contrast sensitivity of the core makers was measured on Monday and Friday of the same week both before and immediately after work and also on a third day, when air samples of TEA were collected. Contrast sensitivity and visual acuity were measured by optotype figures at full contrast, 2.5% contrast, and 0.6% contrast. The changes in contrast sensitivity were used for the analysis. The results of binocular vision and the results of the dominant eye were analysed. Urine specimens for the analysis of TEA were collected on every occasion when contrast sensitivity was measured. RESULTS: 78% of the core makers had had symptoms of blurred vision, and 31% had had trouble driving or working. The breathing zone eight hour time weighted average TEA concentrations were 0.3-60 mg/m3. The mean urinary TEA concentration after the shift was 35 mmol/mol creatinine. Continuous monitoring showed high peaks of TEA leakage at a core making machine. Changes in binocular visual acuity did not differ between the exposed and unexposed workers. The contrast sensitivity decreased in 49% of the core makers and 21% of the controls (P = 0.002). CONCLUSIONS: The blurred vision caused by exposure to TEA can be documented by measuring contrast sensitivity. The mechanism by which TEA produces symptoms remains an issue of further study.
No increased DNA damage in peripheral lymphocytes of sewage workers as evaluated by alkaline single cell gel electrophoresis.
Authors: Friis L , Vaghef H , Edling C , Hellman B
Published: December 2008

OBJECTIVES: To study whether sewage workers are exposed to genotoxic substances. An increased risk of cancers among sewage workers has been noted. If this increased risk is due to an exposure to genotoxic agents, primarily DNA damage could be used as a biological marker of exposure. METHODS: In a cross sectional study, DNA damage in peripheral lymphocytes from 35 sewage workers and 30 controls was compared with alkaline single cell gel electrophoresis, a technique for detecting single strand breaks and alkali labile sites in DNA. The controls were selected from among municipal workers matched for age and smoking habit. Information about occupational exposures and possible confounders was collected by means of a questionnaire. RESULTS: No increase in DNA damage was found among the sewage workers when compared with the unexposed controls. CONCLUSIONS: The failure to detect increased damage to DNA in peripheral lymphocytes by alkaline single cell gel electrophoresis suggests that the sewage workers studied here were not exposed to genotoxic agents to a greater extent than other municipal workers. It may be, however, that the lymphocyte is not the appropriate target cell to study, or that sewage workers are exposed to carcinogens which do not damage the genetic material.
Priorities in occupational health research: a Delphi study in The Netherlands.
Authors: van der Beek A J , Frings-Dresen M H , van Dijk F J , Houtman I L
Published: December 2008

OBJECTIVES: To achieve a coherent programme of topics for research in occupational health and safety, with well founded priorities and to relate them to perceived gaps and needs in The Netherlands. METHODS: In the first phase of the study 33 key informants were interviewed. In the second phase questionnaires were sent to 150 Dutch experts (including the key informants). Four groups were recruited, originating from: occupational health and safety services; scientific research institutes; governmental and other administrative bodies; and companies. Using the Delphi technique, the experts were asked to prioritize several topics, which were placed under different headings. In the third phase five workshops were organised to elaborate on the highly prioritized topics. RESULTS: The response rates were 86% for the first and 81% for the second questionnaire. In the second round consistency was reached and consensus proved to be satisfactory; so that the Delphi process was stopped. There were surprisingly few differences in opinion between the four groups. The most important heading was "design/implementation/evaluation of measures", in which the topic cost-benefit analysis of measures had the highest score. "Assessment of relations between exposure and effect" was the second most important heading. Under this heading, topics on work stress were generally judged to be more important than topics on safety and biological, chemical, and physical hazards. The headings "occupational rehabilitation/sociomedical guidance" and "occupational health care/occupational health services" had about the sam priority, closely following the heading "assessment of relations between exposure and effect". CONCLUSIONS: The general agreement on priorities should provide a sufficiently broad basis for decision makers to initiate a long term programme for occupational health research and development in The Netherlands.
Carpal tunnel syndrome: what is attributable to work? The Montreal study.
Authors: Rossignol M , Stock S , Patry L , Armstrong B
Published: December 2008

OBJECTIVE: To estimate the fraction of carpal tunnel syndrome (CTS) that is attributable to work in the total adult population of the island of Montreal. METHODS: The population consisted of 1.1 million people 20-64 years of age, with 73.2% of men and 60.6% of women employed. The rates of first surgery for CTS were compared between occupational groups and the total adult population with the standardised incidence ratio (SIR) method. Rates of surgery for the island of Montreal were obtained from the provincial data base of payments. The occupational history was obtained from telephone interviews of a sample of surgical cases. The attributable fractions in exposed people were calculated with odds ratios (ORs) obtained from logistic regressions with non-manual workers as the control group. RESULTS: The surgical incidence of CTS was 0.9/1000 adults. SIRs for all manual workers were 1.9 (95% confidence interval (95% CI) 1.4-2.5) in men and 1.8 (95% CI 1.4-2.2) in women, and the fractions attributable to work were 76% (95% CI 47-88) and 55% (95% CI 33-69), respectively. Seven occupational groups were identified as having excess risk of surgical CTS, with fractions attributable to occupation ranging from 75% to 99%. CONCLUSION: Among manual workers on the island of Montreal, 55% of surgical CTS in women and 76% in men was attributable to work. Increased risk of surgical CTS was found in seven occupational groups.
Exposure and mineralogical correlates of pulmonary fibrosis in chrysotile asbestos workers.
Authors: Green F H , Harley R , Vallyathan V , Althouse R , Fick G , Dement J , Mitha R , Pooley F
Published: December 2008

OBJECTIVES: The relation between lifetime cumulative exposure to asbestos, pathological grade of pulmonary fibrosis, and lung burden of asbestos at death, was explored in a necropsy population of former workers in a chrysotile asbestos textile plant in South Carolina. METHODS: Estimates of cumulative, mean, and peak exposures to asbestos were available for 54 workers. Necropsy records and lung tissue samples were obtained from hospital files. Matched control cases were selected from consecutive necropsies performed at the same hospitals. The extent and severity of pulmonary fibrosis was graded on tissue sections. Mineral fibres in lung tissue were characterised by transmission electron microscopy combined with x ray spectroscopy. RESULTS: A significant positive correlation (r = 0.67, P < 0.0001) was found between lifetime cumulative exposure to asbestos and total lung burden of asbestos fibres. This relation was also found for the individual types of asbestos associated with the exposure: chrysotile and tremolite. Pulmonary fibrosis was correlated with both cumulative exposure to asbestos (r = 0.60, P < 0.01) and the concentration of asbestos fibres in the lung (r = 0.62, P < 0.0001). The concentration of tremolite fibres in the lung provided a better estimate of lung fibrosis than did the concentration of chrysotile. Asbestosis was usually present in asbestos textile workers with more than 20 fibre-years cumulative exposure. The lengths and aspect ratios of chrysotile asbestos, but not amphibole asbestos, were greater in the lungs of asbestos fibre workers than in the control population. Textile workers with lung cancer had significantly greater cumulative exposures and fibrosis scores than workers without lung cancer. CONCLUSIONS: Both cumulative exposure to asbestos and lung fibre burden are strongly correlated with severity of asbestosis. The data also support the hypothesis that the high prevalence of asbestosis and lung cancer in this population resulted from exposure to long fibres of chrysotile asbestos in the workplace.
A nested case-control study of fatal work related injuries among Brazilian steel workers.
Authors: Barreto S M , Swerdlow A J , Smith P G , Higgins C D
Published: December 2008

OBJECTIVES: To estimate the relative risk of death from work related injury in a steelworks, associated with exposure to various occupational hazards, sociodemographic factors, and medical history. MATERIAL AND METHODS: The study was a nested case-control design. It was based on a cohort of men employed in the steel plant of USIMINAS, Brazil between January 1977 and August 1990, who were followed up to November 1992. The cases were defined as all workers in the cohort who died from injury in the study period and whose death had been notified to the Brazilian Ministry of Labour as being related to work. Four controls per case, matched to cases on year of birth, were randomly selected from among workers employed in the plant at the time of death of the matching case. Data on potential risk factors for occupational injury were extracted from company records; for the controls these data were abstracted for the period preceding the death of the matching case. RESULTS: There were 37 deaths related to work injuries during the study period. Four surviving workers were selected as controls for each case, but for eight the personnel records were incomplete, leaving 140 controls in all. Significantly increased risk of fatal injury related to work was associated with exposure to noise, heat, dust and fumes, gases and vapours, rotating shift work, being a manual worker, and working in the steel mill, coke ovens, blast furnaces, and energy and water supply areas. Risk of fatal injury related to work increased with intensity of exposure to noise (P (trend) = 0.004) and heat (P < 0.001), and increased greatly with a hazard score that combined information on noise, heat, dust, and gas exposure (P < 0.001). Number of years of schooling (P = 0.03) and salary level (P = 0.03) were both negatively associated with risk. In a multivariate analysis including all these significant factors, only hazard score and area of work remained associated with death from injury related to work. The highest risks were for men exposed to all four environmental hazards (odds ratio (OR) 19.4; 95% confidence interval (95% CI) 1.1 to 352.1) and those working in the energy supply area (OR 18.0; 1.6 to 198.1). CONCLUSIONS: The study identified parts of the steelworks and types of hazard associated with greatly increased risk of fatal accident. Research and measures to prevent accidents need to concentrate on these areas and the people working in them. The use of a hazard score was successful in identifying high risk, and similar scoring might prove useful in other industrial situations.
Biological monitoring of environmental exposure to PAHs in the vicinity of a Söderberg aluminium reduction plant.
Authors: Gilbert N L , Viau C
Published: December 2008

OBJECTIVES: To assess environmental exposure to polycyclic aromatic hydrocarbons (PAHs) in the vicinity of a Söderberg aluminium reduction plant in Shawinigan, Canada with urinary 1-hydroxypyrene (1-OHP) as a biomarker. METHODS: Urine samples were collected from 20 non-occupationally exposed subjects living less than 500 m from the plant and from 20 controls living in Trois-Rivières, another industrial town 40 km from Shawinigan. Concentrations of 1-OHP were measured by high performance liquid chromatography (HPLC). RESULTS: Among controls, geometric mean (range) 1-OHP concentrations were 0.046 (0.012-0.116) mumol/mol creatinine in non-smokers and 0.125 (0.051-0.282) mumol/mol creatinine in smokers. Among exposed subjects, values were 0.103 (0.056-0.196) mumol/mol creatinine in non-smokers and 0.250 (0.112-0.448) mumol/mol creatinine in smokers. Excretion of 1-OHP was significantly higher in exposed subjects than in controls among non-smokers and smokers (P < 0.05). CONCLUSION: Based on urinary 1-OHP as a biomarker, it seems that living near an industrial point source of PAHs is associated with higher exposure. The health significance of this finding will require further investigation.
Exposure-response analysis of risk of respiratory disease associated with occupational exposure to chrysotile asbestos.
Authors: Stayner L , Smith R , Bailer J , Gilbert S , Steenland K , Dement J , Brown D , Lemen R
Published: December 2008

OBJECTIVES: To evaluate alternative models and estimate risk of mortality from lung cancer and asbestosis after occupational exposure to chrysotile asbestos. METHODS: Data were used from a recent update of a cohort mortality study of workers in a South Carolina textile factory. Alternative exposure-response models were evaluated with Poisson regression. A model designed to evaluate evidence of a threshold response was also fitted. Lifetime risks of lung cancer and asbestosis were estimated with an actuarial approach that accounts for competing causes of death. RESULTS: A highly significant exposure-response relation was found for both lung cancer and asbestosis. The exposure-response relation for lung cancer seemed to be linear on a multiplicative scale, which is consistent with previous analyses of lung cancer and exposure to asbestos. In contrast, the exposure-response relation for asbestosis seemed to be nonlinear on a multiplicative scale in this analysis. There was no significant evidence for a threshold in models of either the lung cancer or asbestosis. The excess lifetime risk for white men exposed for 45 years at the recently revised OSHA standard of 0.1 fibre/ml was predicted to be about 5/1000 for lung cancer, and 2/1000 for asbestosis. CONCLUSIONS: This study confirms the findings from previous investigations of a strong exposure-response relation between exposure to chrysotile asbestos and mortality from lung cancer, and asbestosis. The risk estimates for lung cancer derived from this analysis are higher than those derived from other populations exposed to chrysotile asbestos. Possible reasons for this discrepancy are discussed.
Risk factors for sensitisation to methyltetrahydrophthalic anhydride.
Authors: Yokota K , Johyama Y , Yamaguchi K , Fujiki Y , Takeshita T , Morimoto K
Published: December 2008

OBJECTIVES: To examine an association between specific IgE to methyltetrahydrophthalic anhydride (MTHPA) and exposure time, atopic history, smoking habits, and total IgE concentrations. METHODS: A cross sectional survey was carried out on a population of 148 workers from two condenser plants using epoxy resin with MTHPA, an acid anhydride curing agent known to cause allergy. RESULTS: Using a Pharmacia CAP system with a MTHPA human serum albumin conjugate, specific IgE antibody was detected in serum from 97 (66%) out of the 148 workers exposed to MTHPA. Stepwise multiple linear regression analysis showed a striking relation between log concentrations of specific and total IgE (P < 0.0001). Furthermore, when the workers were divided into two groups according to a cut-off point (100 IU/ml) between low and high total IgE, current smoking was significantly (P = 0.025) associated with specific IgE production only in the group with low total IgE (< 100 IU/ml). CONCLUSIONS: Smoking is the most significant risk factor for raising specific IgE to MTHPA in the group with low total IgE concentrations.
Effects of exposure to microwaves on cellular immunity and placental steroids in pregnant rats.
Authors: Nakamura H , Seto T , Nagase H , Yoshida M , Dan S , Ogino K
Published: December 2008

OBJECTIVES: Microwaves produce various detrimental changes based on actions of heat or non-specific stress, although the effects of microwaves on pregnant organisms has not been uniform. This study was designed to clarify the effect of exposure to microwaves during pregnancy on endocrine and immune functions. METHODS: Natural killer cell activity and natural killer cell subsets in the spleen were measured, as well as some endocrine indicators in blood--corticosterone and adrenocorticotrophic hormone (ACTH) as indices of the hypothalamic-pituitary-adrenal axis--beta-endorphin, oestradiol, and progesterone in six female virgin rats and six pregnant rats (nine to 11 days gestation) exposed to microwaves at 10 mW/cm2 incident power density at 2450 MHz for 90 minutes. The same measurements were performed in control rats (six virgin and six pregnant rats). RESULTS: Skin temperature in virgin and pregnant rats increased immediately after exposure to microwaves. Although splenic activity of natural killer cells and any of the subset populations identified by the monoclonal antibodies CD16 and CD57 did not differ in virgin rats with or without exposure to microwaves, pregnant rats exposed to microwaves showed a significant reduction of splenic activity of natural killer cells and CD16+CD57-. Although corticosterone and ACTH increased, and oestradiol decreased in exposed virgin and pregnant rats, microwaves produced significant increases in beta-endorphin and progesterone only in pregnant rats. CONCLUSIONS: Microwaves at the power of 10 mW/cm2 produced activation of the hypothalamic-pituitary-adrenal axis and increased oestradiol in both virgin and pregnant rats, suggesting that microwaves greatly stress pregnant organisms. These findings in pregnant rats suggest that--with exposure to microwaves--pregnancy induces immunosuppression, which could result in successful maintainance of pregnancy. This enhancement of adaptability to heat stress with pregnancy may be mediated by activation of placental progesterone and placental or pituitary beta-endorphin.
Cancer incidence of workers in the Swedish petroleum industry.
Authors: Järvholm B , Mellblom B , Norrman R , Nilsson R , Nordlinder R
Published: December 2008

OBJECTIVES: To estimate the risk of cancer due to occupational exposure to petroleum products in the Swedish transport and refinery industries. METHODS: In a retrospective cohort study the cancer incidence in 4128 men and 191 women, who had worked for at least one year in the petroleum industry, was compared with the incidence in the general population. The job titles and employment times for each person were found in personal files in the industries. The men had on average worked in jobs exposed to petroleum for 11.6 years at the end of the observation period. The cases of cancer were identified by record linkage with the Swedish cancer register. RESULTS: In total there were 146 cases of cancer v 157.6 expected (standardised mortality ratio (SMR) 0.93 90% confidence interval (90% CI) 0.80 to 1.1). Operators at refineries had an increased risk of leukaemia (6 cases v 1.7 expected, 90% CI of relative risk (RR) 1.5 to 7.0). Five of the six cases had started to work at the refineries in the 1950s or later. No other significantly increased risk of cancer was found. Distribution workers had a decreased incidence of lung cancer (no cases, 90% CI of RR 0 to 0.4). CONCLUSIONS: Operators at Swedish refineries had an increased risk of leukaemia. A possible cause is exposure to benzene. There was no increased risk of leukaemia in distribution workers. Distribution workers had a decreased risk of lung cancer.
EnGenIUS — ENVIRONMENTAL GENOME INFORMATIONAL UTILITY SYSTEM
Authors: KAPLAREVIC MIHAILO , MURRAY ALISON E. , CARY STEPHEN C. , GAO GUANG R.
Published: December 2008

Short-insert shotgun sequencing approaches have been applied in recent years to environmental genomic libraries. In the case of complex multispecies microbial communities, there can be many sequence reads that are not incorporated into assemblies, and thus need to be annotated and accessible as single reads. Most existing annotation systems and genome databases accommodate assembled genomes containing contiguous gene-encoding sequences. Thus, a solution is required that can work effectively with environmental genomic annotation information to facilitate data analysis. The Environmental Genome Informational Utility System (EnGenIUS) is a comprehensive environmental genome (metagenome) research toolset that was specifically designed to accommodate the needs of large (> 250 K sequence reads) environmental genome sequencing efforts. The core EnGenIUS modules consist of a set of UNIX scripts and PHP programs used for data preprocessing, an annotation pipeline with accompanying analysis tools, two entity relational databases, and a graphical user interface. The annotation pipeline has a modular structure and can be customized to best fit input data set properties. The integrated entity relational databases store raw data and annotation analysis results. Access to the underlying databases and services is facilitated through a web-based graphical user interface. Users have the ability to browse, upload, download, and analyze preprocessed data, based on diverse search criteria. The EnGenIUS toolset was successfully tested using the Alvinella pompejana epibiont environmental genome data set, which comprises more than 300 K sequence reads. A fully browsable EnGenIUS portal is available at (access code: "guest"). The scope of this paper covers the implementation details and technical aspects of the EnGenIUS toolset.
HAPLOTYPE INFERENCE AND BLOCK PARTITIONING IN MIXED POPULATION SAMPLES
Authors: SAZONOVA NADEZHDA , HARNER E. JAMES
Published: December 2008

Multi-population haplotype inference and block partitioning is a difficult task when dealing with mixed genotype samples. A number of studies have shown that the haplotype block structures, as well as the collections of common haplotypes and their frequencies, vary significantly among world populations. These differences are more extreme when the geographical locations for the populations are more distant. Some of the previous studies performed haplotype inference in multi-population samples with known population assignment. Others developed algorithms for clustering of the mixed haplotype or genotype samples with different block structures or genetic marker profiles. We present a new algorithm that performs haplotype inference and block partitioning in a mixed sample of genotypes from two populations when the population assignments are not known. Given a mixed genotype sample, the proposed algorithm (HAPLOCLUST) extracts two clusters of genotypes with different block structures in addition to performing haplotype inference on each of these clusters. When tested on a set of unrelated individuals, our algorithm provides correct assignments comparable to those of two state-of-the-art algorithms for population stratification. The contribution of HAPLOCLUST consists of performing haplotype/block-based population stratification and simultaneously finding the haplotype resolution and block partitioning for the extracted clusters.
A LINEAR-TIME ALGORITHM FOR PREDICTING FUNCTIONAL ANNOTATIONS FROM PPI NETWORKS
Authors: WU YONGHUI , LONARDI STEFANO
Published: December 2008

Recent proteome-wide screening efforts have made available genome-wide, high-throughput protein–protein interaction (PPI) maps for several model organisms. This has enabled the systematic analysis of PPI networks, which has become one of the primary challenges for the systems biology community. Here, we address the problem of predicting the functional classes of proteins (i.e. GO annotations) based solely on the structure of the PPI network. We present a maximum likelihood formulation of the problem and the corresponding learning and inference algorithms. The time complexity of both algorithms is linear in the size of the PPI network, and our experimental results show that their accuracy in functional prediction outperforms current existing methods.
On the impact of combinatorial structure on congestion games
Authors: Ackermann Heiner , Röglin Heiko , Vöcking Berthold
Published: December 2008

We study the impact of combinatorial structure in congestion games on the complexity of computing pure Nash equilibria and the convergence time of best response sequences. In particular, we investigate which properties of the strategy spaces of individual players ensure a polynomial convergence time. We show that if the strategy space of each player consists of the bases of a matroid over the set of resources, then the lengths of all best response sequences are polynomially bounded in the number of players and resources. We also prove that this result is tight, that is, the matroid property is a necessary and sufficient condition on the players' strategy spaces for guaranteeing polynomial-time convergence to a Nash equilibrium.

In addition, we present an approach that enables us to devise hardness proofs for various kinds of combinatorial games, including first results about the hardness of market sharing games and congestion games for overlay network design. Our approach also yields a short proof for the PLS-completeness of network congestion games. In particular, we show that network congestion games are PLS-complete for directed and undirected networks even in case of linear latency functions.
Weak ε-nets and interval chains
Authors: Alon Noga , Kaplan Haim , Nivasch Gabriel , Sharir Micha , Smorodinsky Shakhar
Published: December 2008

We construct weak ε-nets of almost linear size for
certain types of point sets. Specifically, for planar point sets in
convex position we construct weak 1/r-nets of size O(rα(r)),
where α(r) denotes the inverse Ackermann function. For point
sets along the moment curve in ℝ
d
we construct
weak 1/r-nets of size r · 2
poly(α(r))
,
where the degree of the polynomial in the exponent depends
(quadratically) on d.

Our constructions result from a reduction to a new problem,
which we call stabbing interval chains with j-tuples. Given the
range of integers N = [1, n], an interval chain of length k is a
sequence of k consecutive, disjoint, nonempty intervals contained
in N. A j-tuple $\bar{P}$ = (p1,…,pj) is said to stab an
interval chain C = I
1
…I
k
if each
p
i
falls on a different interval of C. The problem is to
construct a small-size family Z of j-tuples that stabs all
k-interval chains in N.

Let z
(j)
k
(n) denote the minimum size of
such a family Z. We derive almost-tight upper and lower bounds for
z
(j)
k
(n) for every fixed j; our bounds
involve functions α
m
(n) of the inverse Ackermann
hierarchy. Specifically, we show that for j = 3 we have
z
(3)
k
(n) =
Θ(nα
$\lfloor$k/2$\rfloor$
(n)) for all k ≥
6. For each j≥4, we construct a pair of functions
Pʹ
j
(m), Qʹ
j
(m), almost equal
asymptotically, such that z
(j)
Pʹ
j(m)(n)
= O(nα
m
(n)) and
z
(j)
Qʹ
j(m)(n) =
Ω(nα
m
(n)).
EXE
Authors: Cadar Cristian , Ganesh Vijay , Pawlowski Peter M. , Dill David L. , Engler Dawson R.
Published: December 2008

This article presents EXE, an effective bug-finding tool that automatically generates inputs that crash real code. Instead of running code on manually or randomly constructed input, EXE runs it on symbolic input initially allowed to be anything. As checked code runs, EXE tracks the constraints on each symbolic (i.e., input-derived) memory location. If a statement uses a symbolic value, EXE does not run it, but instead adds it as an input-constraint; all other statements run as usual. If code conditionally checks a symbolic expression, EXE forks execution, constraining the expression to be true on the true branch and false on the other. Because EXE reasons about all possible values on a path, it has much more power than a traditional runtime tool: (1) it can force execution down any feasible program path and (2) at dangerous operations (e.g., a pointer dereference), it detects if the current path constraints allow
any
value that causes a bug. When a path terminates or hits a bug, EXE automatically generates a test case by solving the current path constraints to find concrete values using its own co-designed constraint solver, STP. Because EXE’s constraints have no approximations, feeding this concrete input to an uninstrumented version of the checked code will cause it to follow the same path and hit the same bug (assuming deterministic code).

EXE works well on real code, finding bugs along with inputs that trigger them in: the BSD and Linux packet filter implementations, the dhcpd DHCP server, the pcre regular expression library, and three Linux file systems.
Fast and Black-box Exploit Detection and Signature Generation for Commodity Software
Authors: Wang Xiaofeng , Li Zhuowei , Choi Jong Youl , Xu Jun , Reiter Michael K. , Kil Chongkyung
Published: December 2008

In biology, a
vaccine
is a weakened strain of a virus or bacterium that is intentionally injected into the body for the purpose of stimulating antibody production. Inspired by this idea, we propose a
packet vaccine
mechanism that randomizes address-like strings in packet payloads to carry out fast exploit detection and signature generation. An exploit with a randomized jump address behaves like a vaccine: it will likely cause an exception in a vulnerable program’s process when attempting to hijack the control flow, and thereby expose itself. Taking that exploit as a template, our signature generator creates a set of new vaccines to probe the program in an attempt to uncover the necessary conditions for the exploit to happen. A signature is built upon these conditions to shield the underlying vulnerability from further attacks. In this way, packet vaccine detects exploits and generates signatures in a black-box fashion, that is, not relying on the knowledge of a vulnerable program’s source and binary code. Therefore, it even works on the commodity software obfuscated for the purpose of copyright protection. In addition, since our approach avoids the expense of tracking the program’s execution flow, it performs almost as fast as a normal run of the program and is capable of generating a signature of high quality within seconds or even subseconds. We present the design of the packet vaccine mechanism and an example of its application. We also describe our proof-of-concept implementation and the evaluation of our technique using real exploits.
Puppetnets
Authors: Antonatos Spiros , Akritidis Periklis , Lam Vinh The , Anagnostakis Kostas G.
Published: December 2008

Most of the recent work on Web security focuses on preventing attacks that directly harm the browser’s host machine and user. In this paper we attempt to quantify the threat of browsers being indirectly misused for attacking third parties. Specifically, we look at how the existing Web infrastructure (e.g., the languages, protocols, and security policies) can be exploited by malicious or subverted Web sites to remotely instruct browsers to orchestrate actions including denial of service attacks, worm propagation, and reconnaissance scans. We show that attackers are able to create powerful botnet-like infrastructures that can cause significant damage. We explore the effectiveness of countermeasures including anomaly detection and more fine-grained browser security policies.