bluuebunny/crossref_metadata_2025 huggingface dataset:
An Interval-Based Method for Workspace Analysis of Planar Flexure-Jointed Mechanism
Authors: Oetomo D. , Daney D. , Shirinzadeh B. , Merlet J.-P.
Published: December 2008

This paper addresses the problem of certifying the performance of a precision flexure-based mechanism design with respect to the given constraints. Due to the stringent requirements associated with flexure-based precision mechanisms, it is necessary to be able to evaluate and certify the performance at the design stage, taking into account the possible sources of errors such as fabrication tolerances and the modeling inaccuracies in flexure joints. An interval-based method is proposed to certify whether various constraints are satisfied for all points within a required workspace. Unlike the finite-element methods that are commonly used today to evaluate a design, where material properties are used for evaluation on a point-to-point sampling basis, the proposed technique offers a wide range of versatility in the design criteria to be evaluated and the results are true for all continuous values within the certified range of the workspace. This paper takes a pedagogical approach in presenting the interval-based methodologies and the implementation on a planar 3revolute-revolute-revolute (RRR) parallel flexure-based manipulator.
Avian Paternal Care Had Dinosaur Origin
Authors: Varricchio David J. , Moore Jason R. , Erickson Gregory M. , Norell Mark A. , Jackson Frankie D. , Borkowski John J.
Published: December 2008

The repeated discovery of adult dinosaurs in close association with egg clutches leads to speculation over the type and extent of care exhibited by these extinct animals for their eggs and young. To assess parental care in Cretaceous troodontid and oviraptorid dinosaurs, we examined clutch volume and the bone histology of brooding adults. In comparison to four archosaur care regressions, the relatively large clutch volumes of
Troodon, Oviraptor
, and
Citipati
scale most closely with a bird-paternal care model. Clutch-associated adults lack the maternal and reproductively associated histologic features common to extant archosaurs. Large clutch volumes and a suite of reproductive features shared only with birds favor paternal care, possibly within a polygamous mating system. Paternal care in both troodontids and oviraptorids indicates that this care system evolved before the emergence of birds and represents birds' ancestral condition. In extant birds and over most adult sizes, paternal and biparental care correspond to the largest and smallest relative clutch volumes, respectively.
Stable Prenucleation Calcium Carbonate Clusters
Authors: Gebauer Denis , Völkel Antje , Cölfen Helmut
Published: December 2008

Calcium carbonate forms scales, geological deposits, biominerals, and ocean sediments. Huge amounts of carbon dioxide are retained as carbonate ions, and calcium ions represent a major contribution to water hardness. Despite its relevance, little is known about the precipitation mechanism of calcium carbonate, and specified complex crystal structures challenge the classical view on nucleation considering the formation of metastable ion clusters. We demonstrate that dissolved calcium carbonate in fact contains stable prenucleation ion clusters forming even in undersaturated solution. The cluster formation can be characterized by means of equilibrium thermodynamics, applying a multiple-binding model, which allows for structural preformation. Stable clusters are the relevant species in calcium carbonate nucleation. Such mechanisms may also be important for the crystallization of other minerals.
Inhibition of Lassa and Marburg Virus Production by Tetherin
Authors: Sakuma Toshie , Noda Takeshi , Urata Shuzo , Kawaoka Yoshihiro , Yasuda Jiro
Published: December 2008

Recently, tetherin has been identified as an effective cellular factor that prevents the release of human immunodeficiency virus type 1. Here, we show that the production of virus-like particles induced by viral matrix proteins of Lassa virus or Marburg virus was markedly inhibited by tetherin and that N-linked glycosylation of tetherin was dispensable for this antiviral activity. Our data also suggest that viral matrix proteins or one or more components that originate from host cells are targets of tetherin but that viral surface glycoproteins are not. These results suggest that tetherin inhibits the release of a wide variety of enveloped viruses from host cells by a common mechanism.
Structural Characterization of the Rous Sarcoma Virus RNA Stability Element
Authors: Weil Jason E. , Hadjithomas Michalis , Beemon Karen L.
Published: December 2008

In eukaryotic cells, an mRNA bearing a premature termination codon (PTC) or an abnormally long 3′ untranslated region (UTR) is often degraded by the nonsense-mediated mRNA decay (NMD) pathway. Despite the presence of a 5- to 7-kb 3′ UTR, unspliced retroviral RNA escapes this degradation. We previously identified the Rous sarcoma virus (RSV) stability element (RSE), an RNA element downstream of the
gag
natural translation termination codon that prevents degradation of the unspliced viral RNA. Insertion of this element downstream of a PTC in the RSV
gag
gene also inhibits NMD. Using partial RNase digestion and selective 2′-hydroxyl acylation analyzed by primer extension (SHAPE) chemistry, we determined the secondary structure of this element. Incorporating RNase and SHAPE data into structural prediction programs definitively shows that the RSE contains an AU-rich stretch of about 30 single-stranded nucleotides near the 5′ end and two substantial stem-loop structures. The overall secondary structure of the RSE appears to be conserved among 20 different avian retroviruses. The structural aspects of this element will serve as a tool in the future design of
cis
mutants in addressing the mechanism of stabilization.
Vacuolar Protein Sorting Pathway Contributes to the Release of Marburg Virus
Authors: Kolesnikova Larissa , Strecker Thomas , Morita Eiji , Zielecki Florian , Mittler Eva , Crump Colin , Becker Stephan
Published: December 2008

VP40, the major matrix protein of Marburg virus, is the main driving force for viral budding. Additionally, cellular factors are likely to play an important role in the release of progeny virus. In the present study, we characterized the influence of the vacuolar protein sorting (VPS) pathway on the release of virus-like particles (VLPs), which are induced by Marburg virus VP40. In the supernatants of HEK 293 cells expressing VP40, different populations of VLPs with either a vesicular or a filamentous morphology were detected. While the filaments were almost completely composed of VP40, the vesicular particles additionally contained considerable amounts of cellular proteins. In contrast to that in the vesicles, the VP40 in the filaments was regularly organized, probably inducing the elimination of cellular proteins from the released VLPs. Vesicular particles were observed in the supernatants of cells even in the absence of VP40. Mutation of the late-domain motif in VP40 resulted in reduced release of filamentous particles, and likewise, inhibition of the VPS pathway by expression of a dominant-negative (DN) form of VPS4 inhibited the release of filamentous particles. In contrast, the release of vesicular particles did not respond significantly to the expression of DN VPS4. Like the budding of VLPs, the budding of Marburg virus particles was partially inhibited by the expression of DN VPS4. While the release of VLPs from VP40-expressing cells is a valuable tool with which to investigate the budding of Marburg virus particles, it is important to separate filamentous VLPs from vesicular particles, which contain many cellular proteins and use a different budding mechanism.
Residual neurobehavioural effects associated with chronic exposure to mercury vapour.
Authors: Kishi R , Doi R , Fukuchi Y , Satoh H , Satoh T , Ono A , Moriwaka F , Tashiro K , Takahata N , Sasatani H
Published: December 2008

To find the residual effects of long term exposure to mercury vapour, neurobehavioural tests were given to ex-mercury miners about 18 years after the end of mercury exposure. Seventy six male ex-mercury miners who had been exposed to high concentrations of mercury vapour (over 1.0 mg/m3) and with a history of mercury intoxication were compared with controls matched for age (within 3 years), sex, and education. Although the extent of the workers' symptoms caused by mercury poisoning, termed erethismus merculialis, decreased considerably after the end of exposure, matched paired comparison showed that performances of motor coordination, simple reaction time, and short term memory had deteriorated significantly in the exposed group. Multiple linear regression analysis of exposure variables with neurological examination measures showed positive correlations between poorer neurological performance and variables related to mercury exposure. Thus the duration of exposure correlated with poorer performance of hand-eye coordination, tapping, and a colour card reading test. Job categories classified by exposure to mercury also had a significant negative correlation with these performances. The period of years after the end of exposure had a significant correlation with better performance of reaction time and digit span. On the other hand, the history of intoxication itself had no significant correlation with any of the current neurobehavioural performances. These results suggest that there are slight but persistent effects on neurobehavioural function, especially on motor coordination, among mercury miners even more than 10 years after the end of exposure.
Longitudinal study of workers exposed to mercury vapour at low concentrations: time course of inorganic and organic mercury concentrations in urine, blood, and hair.
Authors: Ishihara N , Urushiyama K
Published: December 2008

Seven Japanese female workers exposed to mercury vapour at a concentration of < 0.02 mg Hg/m3 (8 h/day, 44 h/week) were examined for inorganic (I-Hg) and organic (O-Hg) mercury concentrations in urine, blood, and hair after 0, 4, 8, 17, and 23 months of exposure. Both I-Hg and O-Hg concentrations in urine and hair did not increase significantly even after 23 months of exposure. The concentration of I-Hg and O-Hg in plasma and O-Hg in erythrocytes, however, increased significantly after four months of exposure, and the high concentrations were maintained until the end of the study (23 months of exposure). Absence of a significant increase in the concentration of O-Hg in hair indicates that changes in concentrations of I-Hg and O-Hg in blood could be caused by the occupational exposure to mercury vapour. These results show clearly that mercury concentration in blood indicates the uptake of mercury compared with data from before employment with mercury. Even after 23 months of exposure to mercury vapour, however, urinary mercury concentration was not affected.
Mortality of Sardinian lead and zinc miners: 1960-88.
Authors: Cocco P L , Carta P , Belli S , Picchiri G F , Flore M V
Published: December 2008

The mortality of 4740 male workers of two lead and zinc mines was followed up from 1960 to 1988. Exposure to respirable dust was comparable in the two mines, but the median concentration of silica in respirable dust was 10-fold higher in mine B (12.8%) than in mine A (1.2%), but the mean annual exposure to radon daughters in underground workplaces differed in the opposite direction (mine A: 0.13 working levels (WL), mine B: 0.011 WL). Total observed deaths (1205) were similar to expected figures (1156.3) over a total of 119 390.5 person-years at risk. Underground workers of mine B had significant increases in risk of pulmonary tuberculosis (SMR 706, 95% confidence interval (95% CI) 473-1014) and non-malignant respiratory diseases (SMR 518; 95% CI 440-1606), whereas the only significant excess at mine A was for non-malignant respiratory diseases (SMR 246; 95% CI 191-312). Total cancer and lung cancer mortality did not exceed the expectation in the two mines combined. A 15% excess mortality for lung cancer, increased up to an SMR 204 (95% CI 89-470) for subjects employed > or = 26 years, was, however, found among underground workers in mine A who on the average experienced an exposure to radon daughters 10-fold higher than those of mine B. By contrast, despite their higher exposure to silica, mine B underground workers experienced a lower than expected lung cancer mortality. A ninefold increase in risk of peritoneal and retroperitoneal cancer combined was also found among underground workers of mine A (SMR 917; 95% CI 250-2347; based on four deaths). A causal association with workplace exposures is unlikely, however, as the SMR showed an inverse trend by duration of employment. These findings are consistent with low level exposure to radon daughters as a risk factor for lung cancer among metal miners. Exposure to silica at the levels estimated for the mine B underground environment did not increase the risk of lung cancer.
Death of a classified worker probably caused by overexposure to gamma radiation.
Authors: Lloyd D C , Edwards A A , Fitzsimons E J , Evans C D , Railton R , Jeffrey P , Williams T G , White A D , Ikeya M , Sumitomo H
Published: December 2008

This paper describes the case of an industrial radiographer who was seriously overexposed to gamma radiation. The exact circumstances of this exposure were not established but it was concluded that he was repeatedly irradiated probably to a total average whole body dose of at least 10 Gy over several years. Also, a much larger dose to a hand required its partial amputation. He developed myelodysplasia, which progressed to acute myeloid leukaemia from which he died. Karyotypic examination of the leukaemic blasts showed changes very similar to those associated with secondary leukaemia that may develop after radio or chemotherapy. The paper describes his medical case history, the investigation of his workplace, and the attempts to estimate his radiation dose by chromosomal analysis of blood lymphocytes and electron spin resonance of dental enamel and bone.
Effects on health of a change from a delaying to an advancing shift system.
Authors: Barton J , Folkard S , Smith L , Poole C J
Published: December 2008

OBJECTIVES--Shift work can lead to a range of problems for some people that seem to result from the disturbance of the circadian system, and can broadly be classified as: disturbances of sleep, impaired physical and psychological health, and disturbed social and domestic life. The main attempt to try to reduce these problems has focused on the design of the shift system, and the identification of the most problematic features of the shift system. One such feature is believed to be the direction of shift rotation. Systems that advance are thought to be more problematic than those that delay. The present study examines the change in the direction of shift rotation from a delaying to an advancing system on health and wellbeing. METHODS--Self reported measures of tolerance to shift work were taken two months before and six months after the change. These included sleep difficulties, gastrointestinal problems, psychological ill health, chronic fatigue, social and domestic disruption, job satisfaction, and satisfaction with the shift system. RESULTS--The change from a delaying to an advancing system resulted in an increase in sleep difficulties between successive afternoon shifts, but a decrease in social disruption. There was little evidence of impaired health on the advancing compared with the delaying system. CONCLUSIONS--The increase in sleep difficulties was thought to result from the undesired adaptation of the circadian system to night work, as a result of the afternoon shifts now following a series of night shifts, whereas previously they followed a series of morning shifts. The decrease in social disruption was thought to result from the specific sequence of the shifts and the discontinuous nature of the shift system, in particular, the long week-end off every third week. Lack of reported health related differences are explained in terms of the relatively unharmful nature of the shift system in question, and the relatively short time span over which the study was conducted.
Prediction of the comparative intensity of pneumoconiotic changes caused by chronic inhalation exposure to dusts of different cytotoxicity by means of a mathematical model.
Authors: Katsnelson B A , Konyscheva L K , Sharapova NYe  , Privalova L I
Published: December 2008

A multicompartmental mathematical model has been used to simulate variations in the cytotoxicity of dusts in the kinetics of the retention, in the pulmonary region and tracheobronchial lymph nodes, of practically insoluble quartzite and titanium dioxide dust particles deposited on the free surfaces of the acini from alveolar air. Experiments with these dusts were conducted on rats exposed to virtually the same dust concentrations in the air for an experimental period of 20 weeks and a period of 10 weeks after exposure. Satisfactory approximation to the experimental data on the retention of these dusts is obtained by using the model parameters that depend either on damage to lung macrophages by phagocytosed particles or on the response of the host organism to this damage by enhanced recruitment of neutrophilic leucocytes; all the other variables of the model being unchanged. The values of the "action integral" computed from this model and multiplied by the index of comparative cytotoxicity of particles in vitro satisfactorily approximate to quantitative differences in the intensity of pneumoconioses caused by the dusts under study by the end of the experimental period. On the whole, the results of the mathematical model agree with the hypothesis that the cytotoxicity of particles plays a key part in both the process of retention of dust in the lung parenchyma and lung associated lymph nodes, and the pathological process caused by the retained dust. Thus given the factors and conditions on which the deposition of practically insoluble dusts in the pulmonary region depends, it is necessary to take into account the multiplicative nature of these two effects of cytotoxicity when predicting the comparative risk of pneumoconiosis.
Age specific interactions between smoking and radon among United States uranium miners.
Authors: Steenland K
Published: December 2008

United States uranium miners who smoked have death rates from lung cancer that are intermediate between the rates predicted by the additive and multiplicative models (on a ratio scale) across all age groups. Age specific patterns of interaction have not been thoroughly examined, and most analyses have been internal ones in which there was no truly non-exposed group. Here age specific death rates of lung cancer among ever smoking uranium miners have been examined for conformity with the additive and multiplicative models. The multiplicative model fits well for the youngest and oldest categories, but poorly for the middle age ranges. In the middle age range, predicted rates under the multiplicative model were quite high, surpassing the corresponding United States death rates for all causes combined. If the multiplicative model is assumed to hold across all ages, one hypothesis that might explain the observed age specific patterns is that the full expression on the multiplicative model might not be seen at certain ages due to a limited pool of miners susceptible to lung cancer. These data, however, have several limitations such as small numbers of deaths from lung cancer among never smokers, the use of qualitative rather than quantitative smoking and radon exposure data, and ignorance of the underlying biological mechanisms of interaction.
Lung retention of cerium in humans.
Authors: Pairon J C , Roos F , Iwatsubo Y , Janson X , Billon-Galland M A , Bignon J , Brochard P
Published: December 2008

A retrospective study was conducted to evaluate lung retention of particles containing cerium in subjects with and without previous occupational exposure to mineral dusts. Analytical transmission electron microscopy was performed on 459 samples of bronchoalveolar lavage (BAL) fluid and 75 samples of lung tissue. Study of the distribution of mineralogical species in human samples showed that particles containing cerium were encountered in less than 10% of subjects. The proportion of subjects with particles containing cerium in their biological samples was not different between controls and subjects with previous occupational exposure to fibrous or nonfibrous mineral dusts. This was considered as the background level of lung retention of cerium in the general population. By contrast, determination of the absolute concentration of particles containing cerium in BAL fluid and lung tissue samples showed that 1.2% (from BAL fluid) and 1.5% (from lung tissue) of subjects with previous exposure to mineral particles had high lung retention of particles containing cerium. This study is believed to be the first one in which lung retention of cerium was estimated in the general population.
Biological monitoring of cyclophosphamide and ifosfamide in urine of hospital personnel occupationally exposed to cytostatic drugs.
Authors: Ensslin A S , Stoll Y , Pethran A , Pfaller A , Römmelt H , Fruhmann G
Published: December 2008

The occupational exposure of 21 nurses and pharmacy personnel from eight hospitals to cyclophosphamide and ifosfamide was determined by quantifying the amount of the drugs handled and by measuring the urinary excretion of the unmetabolised substances. Preparing antineoplastic drugs for intravenous treatment was the major task of all study participants. Twenty four hour urine was collected on days when cyclophosphamide and/or ifosfamide were mixed, on average 3900 mg cyclophosphamide and/or 5900 mg ifosfamide. The analyses were performed by gas chromatography with electron capture, detection limit 2.5 micrograms/24 hour urine. Despite standard safety precautions, including a vertical laminar air flow safety cabinet and gloves, cyclophosphamide was detected in 12 of 31 and ifosfamide in four of 21 urine samples on days when the drugs were handled. Excretion of cyclophosphamide ranged from 3.5 to 38 micrograms/24 h (mean 11.4 micrograms/24 h) urine, ifosfamide from 5 to 12.7 micrograms/24 h (mean 9 micrograms/24 h) urine. Based on an excretion rate of 11.3% unmetabolised cyclophosphamide, the average amount excreted corresponded to an uptake of 101 micrograms cyclophosphamide. For ifosfamide the mean quantity incorporated was 20 micrograms assuming that 45% of the drug was excreted. Pertaining to the doses handled, the uptake of cyclophosphamide and ifosfamide was estimated to be approximately 0.0025% and 0.0004% respectively. Despite time-consuming purification procedures, gas chromatographic analysis is a suitable method for monitoring personnel occupationally exposed to cyclophosphamide and ifosfamide and is a major contribution to the evaluation of potential health risks of exposed personnel.
Case-control study of risk factors for disease in the neck and shoulder area.
Authors: Ekberg K , Björkqvist B , Malm P , Bjerre-Kiely B , Karlsson M , Axelson O
Published: December 2008

A case-control study was performed to elucidate the strength of the relation between musculoskeletal disorders in the neck and shoulders and physical, organisational, and psychosocial aspects of the work environment. Cases were identified as those persons who consulted a physician in a community in southern Sweden for new musculoskeletal disorders in the neck and shoulders during a study period from August 1988 to the end of October 1989. One hundred and nine cases were collected and clinically examined. The cases also answered the Nordic questionnaire on symptoms as well as a questionnaire on work conditions and background factors. Controls were drawn as a random sample of the working population in the community where the cases appeared. A total of 637 controls answered the same questionnaires as the cases. Odds ratios (ORs) were calculated by logistic regression. The odds ratios were 11.4 for women, 4.9 for immigrant background, and 3.7 for current smoking. To exercise rarely, compared with often, appeared as a preventive factor with an OR of 0.3. The ORs for various determinants of physical work load were 7.5 for repetitive movements demanding precision, 13.6 for light lifting, 3.6 for uncomfortable sitting positions, 4.8 for work with lifted arms, and 3.5 for a rushed work pace. Regarding work organisational determinants, the ORs were 16.5 for ambiguity of work role (uncertainty whether the person could manage the work) 2.6 for low quality work, and 3.8 for high demands on attention. Several of the determinants showed a significant dose-response relation with disease. It seems that work organisation and psychosocial work conditions are as important determinants for disease in the neck and shoulders as are the physical work conditions.
Chronic elemental mercury intoxication: clinical and field studies in lampsocket manufacturers.
Authors: Yang Y J , Huang C C , Shih T S , Yang S S
Published: December 2008

Four workers chronically exposed to elemental mental mercury in a lampsocket manufacturing factory were studied. The clinical manifestations were severe in one, mild in another, and suspicious in the remaining two. Correlation between severity of clinical features and increased urinary mercury concentrations was found. The time weighted average mercury concentrations were 0.945 mg/m3 and 0.709 mg/m3 for two workers in one room and 0.225 mg/m3 in the other. After stopping exposure, the workers recovered spontaneously or with D-penicillamine treatment within six months. It is concluded that recovery from chronic elemental mercury intoxication may be complete when patients are removed early from the exposure environment. The hazard of mercury intoxication in recycling of waste substances is emphasised.
Sickness absence in diabetic employees at a large engineering factory.
Authors: Poole C J , Gibbons D , Calvert I A
Published: December 2008

It is not known whether employees who have diabetes mellitus lose more time from work due to sickness than non-diabetic employees. A study was undertaken to compare sickness absence in 91 diabetic with 91 non-diabetic employees matched for sex, age, and occupation. Although sickness absence was greater in the diabetic group this was not significant. Mean sickness absence for the diabetic employees and controls was 32 v 20 days/year (95% confidence interval -5 to 29 days). Because of the large variability in sickness absence in both diabetic and non-diabetic employees, a study of this size is probably not sufficiently powerful to detect a difference.
Past exposure to asbestos and combustion products and incidence of cancer among Finnish locomotive drivers.
Authors: Nokso-Koivisto P , Pukkala E
Published: December 2008

Locomotive drivers in the steam engine era were exposed to asbestos during their vocational training for two years while training in workshops. Later in their career they had exposure to coal and diesel combustion products. To assess the level of earlier exposure historical working conditions were reconstructed and hygienic conditions were measured. The average exposure to asbestos (mainly anthophylline) fibres > 5 microns was 5.0 fibres/cm3. Incidence of cancer in a cohort of 8391 members of the Finnish Locomotive Drivers' Association, 1953-91, was analysed. The incidence of lung cancer and also total cancer was below the national average, probably due to the low prevalence of smoking among the drivers in the steam engine era. A four-fold risk of mesothelioma was found, most likely caused by exposure to asbestos. Also the observed 1.5-fold incidence of non-melanoma skin cancer and 1.7-fold risk of cancer of the oral cavity and pharynx may be related to occupation.
Liver function tests and urinary albumin in house painters with previous heavy exposure to organic solvents.
Authors: Lundberg I , Nise G , Hedenborg G , Högberg M , Vesterberg O
Published: December 2008

The serum activities or concentrations of aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), alkaline phosphatase (ALP), albumin, gamma-glutamyl transpeptidase (GGT), bilirubin (BIL), cholic acid (CHOL), chenodeoxycholic acid (CHENO), and transferrin with isoelectric point 5.7, and the urinary excretion of albumin were determined among male current or former house painters (n = 135) and house carpenters (n = 71) who had worked in their trades for at least 10 years before 1970. Workers who showed a value above the 90th percentile among the carpenters in at least one of the tests ASAT, ALAT, GGT, BIL, CHOL, or CHENO were regarded as showing "possible signs of liver dysfunction". Each participant's lifetime solvent exposure was evaluated by interview. The painters were divided into categories with low, intermediate, and heavy cumulative exposure during life (LTSE) or during the most exposed year (MEYSE). All participants stated none or slight recent exposure. The prevalence of possible signs of liver dysfunction increased with solvent exposure category according to LTSE as well as MEYSE with a numerically higher risk estimate in the heavy exposure category for MEYSE than for LTSE. ALP activity increased with exposure category according to both exposure estimates. This increase seemed to be due to an interaction between exposure to solvents and current or previous long term intake of medicines potentially toxic to the liver. None of these results was affected by whether or not the subjects had been exposed to solvents during the year before the investigation. The exposure to solvents was not significantly related to any other outcome variable. It is concluded that long term heavy exposure to solvents may elicit changes in conventional liver function tests indicative of a mild chronic effect on the liver. The findings also suggest that heavy solvent exposure during short time periods is a more likely cause of the findings than lifetime cumulative solvent exposure and that an interaction between solvent exposure and medicines potentially harmful to the liver may be important in the causation of the effects.
Concentrations of phenol, o-cresol, and 2,5-xylenol in the urine of workers employed in the distillation of the phenolic fraction of tar.
Authors: Bieniek G
Published: December 2008

Phenol (87.3 mg/l), p-cresol (58.6 mg/l), o-cresol (76.9 mg/l), and 2,5-xylenol (36.7 mg/l) were detected in the urine of workers employed in the distillation of the high temperature phenolic fraction of tar (carbolic oil). The concentrations of these compounds in the urine of non-exposed male workers was 11.7 mg/l, 25.7 mg/l, 68.1 micrograms/l, and 69 micrograms/l respectively. The excretion rates were 4.20 mg/h for phenol, 2.4 mg/h for p-cresol, 3.3 mg/h for o-cresol; and 1.5 mg/h for 2,5-xylenol. The highest concentrations of the mentioned compounds were detected in urine collected between eight and 10 hours from the beginning of exposure. The kinetics of excretion are considered.
An updated cohort mortality study of workers exposed to styrene in the reinforced plastics and composites industry.
Authors: Wong O , Trent L S , Whorton M D
Published: December 2008

Mortality data have been updated for a further 12 years for a cohort of workers in the reinforced plastics and composites industry with exposures to styrene monomer and other chemicals. The cohort consisted of 15,826 male and female employees who were exposed to styrene for at least six months between 1948 and 1977 at 30 participating manufacturing plants in the United States. A total of 1628 deaths were reported during the extended observation period, 1948-89. Mortality from several causes showed significant increases--namely, all causes, all cancers, oesophageal cancer, lung cancer, cancer of the cervix uteri, cancer of other female genital organs, hypertensive heart disease, certain non-malignant respiratory diseases, motor vehicle accidents, and homicides. When, however, mortality data were examined in terms of duration of employment, durations of styrene exposure, and cumulative styrene exposure no upward trend was detected in any of these causes of death. Most of the increases in mortality were among workers who were employed for only six months to a year or who had very low cumulative exposure (< 10 ppm-years). Therefore, the increased mortality was not likely to be related to exposure to styrene. Several explanations for the increased mortality are offered, including low socioeconomic class, smoking, and lifestyle factors characteristic of short term workers. There was no increased mortality from lymphatic and haematopoietic cancers overall or from any specific haematological malignancies. In particular, no increase in mortality from non-Hodgkin's lymphoma, Hodgkin's disease, multiple myeloma, or leukaemia was found. Furthermore, detailed exposure-response analyses did not show any relation between exposure to styrene and any of these haematological malignancies. The lack of an exposure-response relation further supports the conclusion that workers in the reinforced plastics industry in this study did not experience any increased risk of lymphatic and haematopoietic cancers as a result of their exposure to styrene.
Occupational allergy after exposure to caddis flies at a hydroelectric power plant.
Authors: Kraut A , Sloan J , Silviu-Dan F , Peng Z , Gagnon D , Warrington R
Published: December 2008

A cross sectional survey was conducted in a hydroelectric power plant in which the workforce was exposed to large numbers of caddis flies. 28 of 57 employees participated. About 50% of the participants reported work related eye, nose, and sinus symptoms and wheezing. Working in locations with greater exposure to caddis flies was significantly associated with work related symptoms. 17 workers (61%) were skin prick positive to a laboratory prepared caddis fly antigen (LCFA) made from the remains of caddis flies present in the plant and 11 (39%) had positive reactions to a commercial caddis fly antigen (CCFA). Workers stationed in heavily exposed areas were 3.7 times as likely to have a positive response to the LCFA (p = 0.009) and 5.3 times as likely to have a positive response to the CCFA (p = 0.036). 13 (46%) of survey respondents reported three or more work related symptoms. 10 (91%) CCFA positive workers reported three or more work related symptoms. Pulmonary function studies revealed slight, but not significantly decreased forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and FEV1/FVC ratios in workers who were skin test positive to either caddis fly preparation when compared with those who were negative. One worker who was skin test positive to both antigens had a cross shift fall in FEV1 of 20% predicted. Occupational allergy to caddis flies proved to be a significant health problem at this work site.
Benzene toxicokinetics in humans: exposure of bone marrow to metabolites.
Authors: Watanabe K H , Bois F Y , Daisey J M , Auslander D M , Spear R C
Published: December 2008

A three compartment physiologically based toxicokinetic model was fitted to human data on benzene disposition. Two separate groups of model parameter derivations were obtained, depending on which data sets were being fitted. The model was then used to simulate five environmental or occupational exposures. Predicted values of the total bone marrow exposure to benzene and cumulative quantity of metabolites produced by the bone marrow were generated for each scenario. The relation between cumulative quantity of metabolites produced by the bone marrow and continuous benzene exposure was also investigated in detail for simulated inhalation exposure concentrations ranging from 0.0039 ppm to 150 ppm. At the level of environmental exposures, no dose rate effect was found for either model. The occupational exposures led to only slight dose rate effects. A 32 ppm exposure for 15 minutes predicted consistently higher values than a 1 ppm exposure for eight hours for the total exposure of bone marrow to benzene and the cumulative quantity of metabolites produced by the bone marrow. The general relation between the cumulative quantity of metabolites produced by the bone marrow and the inhalation concentration of benzene is not linear. An inflection point exists in some cases leading to a slightly S shaped curve. At environmental levels (0.0039-10 ppm) the curve bends upward, and it saturates at high experimental exposures (greater than 100 ppm).
Incidence of cancer among anthophyllite asbestos miners in Finland.
Authors: Meurman L O , Pukkala E , Hakama M
Published: December 2008

A cohort of 736 male and 167 female workers of two anthophyllite mines in Finland was followed up through the Finnish Cancer Registry for cancer in 1953-91. Compared with the total cancer incidence of the east Finnish population, the men had a raised risk of total cancer (standardised incidence ratio (SIR) 1.7; 95% confidence interval (95% CI) 1.4-1.9), mainly attributable to an excess in lung cancer (SIR 2.8; 95% CI 2.2-3.6). The risk of lung cancer was somewhat higher among workers classified as heavily exposed (SIR 3.2; 95% CI 2.4-4.1) than among those moderately exposed (SIR 2.3; 95% CI 1.5-3.6) and the risk increased with increasing smoking and with increasing time of work with exposure. There were four cases of mesothelioma v 0.1 expected, all in men who smoked and had had a long and heavy asbestos exposure. Among women, a non-significant excess in total cancer (SIR 1.5; 95% CI 0.9-2.4) was found in the subgroup with heavy exposure to asbestos. Anthophyllite asbestos seems to have high potency in the carcinogenesis of lung cancer and low potency in carcinogenesis of mesothelioma in comparison with the other types of asbestos.
Occupational risk factors for renal cell carcinoma: a case-control study.
Authors: Aupérin A , Benhamou S , Ory-Paoletti C , Flamant R
Published: December 2008

A case-control study of 196 histologically proved cases of renal cell carcinoma and 347 controls matched for age at interview, sex, hospital, and interviewer was conducted in France between 1987 and 1991. A complete occupational history was recorded for each patient and occupations were coded blindly according to the International Standard Classification of Occupations. In women, none of the risks were significant. Among men, after adjustment for the educational level, cigarette smoking, and Quetelet index before diagnosis, significantly increased matched odds ratios (ORs) were found for sales workers (OR = 2.1, 95% confidence interval (95% CI) 1.2-4.0), managers (OR = 3.3, 95% CI 1.2-8.9), and textile workers and tailors (OR = 6.2, 95% CI 1.1-33.7). For this last occupational group, an increase in risk was found with an increased duration of exposure.
Morbidity follow up study of BASF employees exposed to 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD) after a 1953 chemical reactor incident.
Authors: Zober A , Ott M G , Messerer P
Published: December 2008

OBJECTIVE--The aim was to examine the long term morbidity experience of men exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). METHODS--A retrospective cohort morbidity study of 158 men first exposed to TCDD between 17 November 1953 and 16 November 1954 subdivided by chloracne state and back calculated TCDD blood lipid concentration, and 161 referents. Cause specific illness absence and admissions to hospital were examined between 1953 and 1989. RESULTS--On an ever or never basis, thyroid disease and appendicitis were diagnosed more often in the study group; these diseases were not differentially distributed by chloracne state, but were increased in the high TCDD subgroup. An 18% increase in total illness episodes was also seen (p = 0.002); illness rates increased with severity of chloracne and higher TCDD concentration within the chloracne subgroup. There were increases in infectious and parasitic diseases (primarily ill defined intestinal infections), disorders of the peripheral nervous system and sense organs, upper respiratory tract infections, and other skin diseases. Several of these increases correlated with chloracne state and infections disease episodes increased with higher TCDD concentration as well. Occurrences of mental disorders correlated with severity of chloracne, but not TCDD concentration. Benign and unspecified neoplasms were marginally increased in the severe chloracne and high TCDD subgroups. Chronic liver disease was marginally increased in the high TCDD subgroup. Findings relative to occurrence of ulcers, chronic lung disease, and kidney and metabolic disorders were unremarkable. DISCUSSION--For various conditions, increased illness episodes were seen among TCDD exposed employees compared with referents and were associated with either or both chloracne severity and back calculated TCDD concentration. The results are derived from insurance data; hence, it is possible that heightened awareness and personal health concerns led to greater utilisation of medical services in the exposed group. The findings based on TCDD concentration should be less subject to this potential bias.
Cancer incidence and mortality among Swedish leather tanners.
Authors: Mikoczy Z , Schütz A , Hagmar L
Published: December 2008

OBJECTIVES--The aim was to study the incidence of cancer among Swedish leather tanners. METHODS--A cohort of 2026 subjects who had been employed for at least one year between 1900 and 1989 in three Swedish leather tanneries, was established. The cancer incidence and mortality patterns were assessed for the periods 1958-89 and 1952-89 respectively, and cause-specific standardised incidence and mortality ratios (SIRs and SMRs) were calculated. RESULTS--A significantly increased incidence of soft tissue sarcomas (SIR 4.27, 95% confidence interval (95% CI) 1.39-9.97) was found, based on five cases. Excesses, (not statistically significant) was also found for multiple myelomas (SIR 2.54, 95% CI 0.93-5.53), and sinonasal cancer (SIR 3.77, 95% CI 0.46-13.6). CONCLUSIONS--The increased incidence of soft tissue sarcomas adds support to previous findings of an excess mortality in this diagnosis among leather tanners. A plausible cause is exposure to chlorophenols, which had occurred in all three plants. The excess of multiple myelomas may also be associated with exposure to chlorophenol. The association between incidence of cancer and specific chemical exposure will be elucidated in a cohort-based case-referent study.
Endocrine function in mercury exposed chloralkali workers.
Authors: Barregård L , Lindstedt G , Schütz A , Sällsten G
Published: December 2008

OBJECTIVE--The aim was to study whether functional impairment of the pituitary, thyroid, testes, and adrenal glands of humans occupationally exposed to mercury (Hg) vapour can be shown as a result of accumulation of Hg in these glands. METHODS--Basal concentrations of thyrotrophin (TSH), prolactin, free thyroxine (free T4), free 3,5,3'-triiodothyronine (free T3), antibodies against thyroperoxidase, and testosterone in serum, as well as cortisol in morning urine were measured in 41 chloralkali workers exposed (10 years on average) to Hg vapour, and in 41 age matched occupationally unexposed referents. The chloralkali workers had a mean urinary Hg concentration (U-Hg) of 15 nmol/mmol (27 micrograms/g) creatinine, and a mean blood Hg concentration (B-Hg) of 46 nmol/l. For the reference group U-Hg and B-Hg were 1.9 nmol/mmol (3.3 micrograms/g) creatinine and 17 nmol/l respectively. RESULTS--The serum free T4 concentration and the ratio free T4/free T3 were slightly, but significantly, higher in the subgroups with the highest exposure, and the serum free T3 was inversely associated with cumulative Hg exposure. This indicates a possible inhibitory effect of mercury on 5'-deiodinases, which are responsible for the conversion of T4 to the active hormone T3. Serum total testosterone, but not free testosterone, was positively correlated with cumulative Hg exposure. Prolactin, TSH and urinary cortisol concentrations were not significantly associated to exposure. CONCLUSION--Apart from inhibition of the deiodination of T4 to T3, the endocrine functions studied seem not to be affected by exposure to Hg vapour at the exposure levels of the present study. Growth hormone secretion was not studied.
Investigation of the relative contributions of cigarette smoking and mineral dust exposure to activation of circulating phagocytes, alterations in plasma concentrations of vitamin C, vitamin E, and beta carotene, and pulmonary dysfunction in South African gold miners.
Authors: Theron A J , Richards G A , Myer M S , van Antwerpen V L , Sluis-Cremer G K , Wolmarans L , van der Merwe C A , Anderson R
Published: December 2008

OBJECTIVES--To determine the relative effects of cigarette smoking and mineral dust exposure on numbers and activity of circulating phagocytes, plasma nutritional antioxidant state, and pulmonary function in South African gold miners. METHODS--Pulmonary function was assessed spirometrically, whereas reactive oxidant generation by circulating phagocytes, and plasma concentrations of the nutritional antioxidative nutrients vitamin C and vitamin E and beta carotene were measured with chemiluminescence, spectrophotometry, or high performance liquid chromatography respectively. RESULTS--Cigarette smoking, but not mineral dust exposure, was associated with increased numbers and pro-oxidative activity of circulating neutrophils and monocytes, decreased plasma concentrations of vitamin C, and pulmonary dysfunction. DISCUSSION--In this study group occupational exposure to mineral dust has not been found to promote increases in the numbers or reactivity of circulating phagocytes or to be a significant cause of pulmonary dysfunction, the changes found being due primarily to cigarette smoking.
Work related symptoms, sensitisation, and estimated exposure in workers not previously exposed to flour.
Authors: Cullinan P , Lowson D , Nieuwenhuijsen M J , Sandiford C , Tee R D , Venables K M , McDonald J C , Newman Taylor A J
Published: December 2008

Findings are presented from the initial cross sectional phase of a cohort study of employees exposed to flour in bakeries or mills. Of 401 eligible workers in seven sites 344 (86%) were surveyed; symptoms assessed by self completed questionnaire, and sensitisation measured by the response to skin prick tests, were related to intensity of exposure both to total dust and to flour aeroallergen. Among 264 subjects without previous occupational exposure to flour, work related symptoms which started after first employment at the site were related to exposure intensity, especially when exposure was expressed in terms of flour aeroallergen. The relations with eye/nose and skin symptoms were independent of atopic status and cigarette smoking. Positive skin test responses to mixed flour and to alpha amylase were also more frequent with increasing exposure intensity, although this was confounded by atopic status. There was only a weak association between symptoms and specific sensitisation.
Work related symptoms, sensitisation, and estimated exposure in workers not previously exposed to laboratory rats.
Authors: Cullinan P , Lowson D , Nieuwenhuijsen M J , Gordon S , Tee R D , Venables K M , McDonald J C , Newman Taylor A J
Published: December 2008

Findings are presented from the initial cross sectional phase of a cohort study of employees exposed to laboratory rats. Of 366 eligible workers at four sites 323 (88%) were surveyed; symptoms assessed by self completed questionnaire and sensitisation measured by the response to skin prick tests were related to intensity of exposure both to total dust and to rat urinary aeroallergen. Among 238 workers, without previous occupational exposure to rats, work related symptoms, which started after first employment at the site were related to exposure intensity (expressed either in terms of dust or of aeroallergen) at the time of onset of symptoms. These relations were stronger in atopic subjects but were unrelated to smoking. Positive skin tests to rat urinary extract were also more frequent with increased exposure, a relation found in both atopic subjects and in smokers. There was a strong association between work related symptoms and specific sensitisation.