Low personal exposure to benzene and 1,3-butadiene in the Swedish petroleum refinery industry.

PURPOSE: Petroleum refinery workers are exposed to the carcinogens benzene and 1,3-butadiene. Declining exposures have been reported internationally but information on current exposure in the Swedish refinery industry is limited. The aim was to examine refinery workers' personal exposure to benzene and 1,3-butadiene and increase awareness of exposure conditions by collaboration with involved refineries. METHODS: Altogether 505 repeated personal exposure measurements were performed among workers at two refineries. Full-shift measurements were conducted in different exposure groups using Perkin Elmer diffusive samplers filled with Carbopack X. Mean levels were calculated using mixed-effects models. A large fraction of measurements below the limit of detection (LOD) required imputation of computer-generated data. RESULTS: Mean benzene exposure among process technicians was 15.3 µg/m3 (95% CI 10.4-22.5 µg/m3) and 13.7 µg/m3 (95% CI 8.3-22.7 µg/m3) for Refinery 1 and 2, respectively. Process technicians working outdoors had higher exposure than maintenance workers (20.7 versus 5.9 µg/m3, p < 0.01). Working in the harbour and tank park (Refinery 1), compared with the process area, was associated with higher exposure. The 1,3-butadiene exposure was low, 5.4 and 1.8 µg/m3, respectively. The total variation was generally attributed to within-worker variability. CONCLUSIONS: Low benzene and 1,3-butadiene levels were found among refinery workers. Mean benzene exposure was about 1% of the Swedish occupational limit (1500 µg/m3) and for 1,3-butadiene, exposure was even lower. A large fraction of values below the LOD can be managed by carefully modelled, computer-generated data.

Personal exposure to benzene and 1,3-butadiene during petroleum refinery turnarounds and work in the oil harbour.

PURPOSE: Petroleum refinery workers' exposure to the carcinogens benzene and 1,3-butadiene has decreased during normal operations. However, certain occupational groups or events at the refineries still involve a risk of higher exposures. The aim of this study was to examine the personal exposure to benzene and 1,3-butadiene at refinery turnarounds and during work in the oil harbour. METHODS: Personal exposure measurements of benzene and 1,3-butadiene were taken during work shifts, with a priori assumed higher benzene exposure, using PerkinElmer diffusive samplers filled with Carbopack X. Mean exposure levels were calculated, and repeated exposure measurements, when available, were assessed using mixed effect models. Group and individual compliance with the Swedish occupational exposure limit (OEL) was tested for the different exposure groups. RESULTS: Mean benzene exposure levels for refinery workers during the three measured turnarounds were 150, 610 and 960 µg/m3, and mean exposures for oil harbour workers and sewage tanker drivers were 310 and 360 µg/m3, respectively. Higher exposures were associated with handling benzene-rich products. Most occupational groups did not comply with the Swedish OEL for benzene nor did the individuals within the groups. The exposure to 1,3-butadiene was very low, between <1 and 3 % of the Swedish OEL. CONCLUSIONS: Work within the petroleum refinery industry, with potential exposure to open product streams containing higher fractions of benzene, pose a risk of personal benzene exposures exceeding the OEL. Refinery workers performing these work tasks frequently, such as contractors, sewage tanker drivers and oil harbour workers, need to be identified and protected.

Cancer incidence in Swedish oil refinery workers exposed to benzene.

BACKGROUND: Oil refinery workers are exposed to benzene, which is a well-known cause of leukaemia, but results on leukaemia in oil refinery workers have been mixed, and the data on workers' exposure is limited. Oil refinery workers are also exposed to asbestos and several studies have shown increased risk of mesothelioma. AIM: The objective was to investigate cancer incidence, especially leukaemia, at low to moderate exposure to benzene in an update of a previous study of employees at three Swedish oil refineries. METHODS: Cancer incidence was followed up in 2264 men (1548 refinery operators) employed at three oil refineries in Sweden for at least one year. Job types and employment times were collected from complete company files. A retrospective assessment of the benzene exposure was performed by occupational hygienists in collaboration with the refineries using historic measurements as well as detailed information on changes in the industrial hygiene and technological developments. Cases of cancer were retrieved by a linkage with the Swedish Cancer Register through 35-47 years of follow-up and standardized incidence ratios (SIR) with 95% confidence intervals (CI) were calculated. RESULTS: In total, 258 tumors had occurred versus 240 expected (SIR 1.07; 95% CI 0.95-1.21). There were 10 cases of leukaemia, all in refinery operators (SIR 2.4; 95% CI 1.18-4.51). There were three cases of pleural mesothelioma, two of which in refinery operators. The mean estimated cumulative benzene exposure for the cases of leukaemia was 7.9 ppm-years (median 4.9, range 0.1-31.1). DISCUSSION: The study suggests that low to moderate average cumulative benzene exposure increases the risk of leukaemia. Limitations include the modest number of cases and potential misclassification of exposure. CONCLUSION: The present study indicated an increased risk of leukaemia in male oil refinery workers with low to moderate exposure to benzene.

Targeted delivery of antisense oligonucleotides to pancreatic ß-cells.

Antisense oligonucleotide (ASO) silencing of the expression of disease-associated genes is an attractive novel therapeutic approach, but treatments are limited by the ability to deliver ASOs to cells and tissues. Following systemic administration, ASOs preferentially accumulate in liver and kidney. Among the cell types refractory to ASO uptake is the pancreatic insulin-secreting ß-cell. Here, we show that conjugation of ASOs to a ligand of the glucagon-like peptide-1 receptor (GLP1R) can productively deliver ASO cargo to pancreatic ß-cells both in vitro and in vivo. Ligand-conjugated ASOs silenced target genes in pancreatic islets at doses that did not affect target gene expression in liver or other tissues, indicating enhanced tissue and cell type specificity. This finding has potential to broaden the use of ASO technology, opening up novel therapeutic opportunities, and presents an innovative approach for targeted delivery of ASOs to additional cell types.

Determination of 1,2,6-inositol trisphosphate (derivatives) in plasma using iron(III)-loaded adsorbents and capillary zone electrophoresis-(indirect) UV detection.

A method for the determination of 1,2,6-inositol trisphosphate (IP3) and derivatives in plasma by capillary zone electrophoresis with (indirect) UV detection has been developed. The sample pretreatment is based on the selective isolation after complexation of inositol phosphates with iron(III) loaded on an adsorbent. Plasma protein denaturation was performed with sodium dodecyl sulfate. The selectivity of the method is demonstrated with the analysis of phenylacetate-IP3. The recoveries amount to 65% and 88% in plasma and in water, respectively.

Abiotic synthesis of organic compounds under the conditions of submarine hydrothermal systems: a perspective.

Deep-sea hydrothermal systems have been proposed to be likely environments for chemical evolution and the origin of life on Earth. Recently, experiments have, therefore, been carried out in order to test the hypothesis that amino acids can be synthesized under conditions representing hydrothermally altered oceanic crust. The variety of amino acids that have been detected in such experiments corresponds roughly to that reported previously for electric sparking in reducing gas mixtures. The relative yields of the protein amino acids detected are significantly higher than in electric spark discharge experiments, and the overall yields are about an order of magnitude higher. The amino acids are all racemic.

Incidence of cutaneous squamous cell carcinoma in coastal and inland areas of Western Sweden.

BACKGROUND: The incidence of squamous cell carcinoma (SCC) has increased in recent decades, both in Sweden and worldwide. The aim of this study was to investigate the development of SCC over time (1970-2007) in the western part of Sweden (WS), with emphasis on the incidence trends on the coast and in the inland areas. METHODS: Cancer data on SCC for different subareas in WS were obtained from the Swedish Cancer Registry. The incidence standardized for the Swedish population in 2000 was analyzed. The incidence trends were estimated and compared using regression analysis. RESULTS: The incidence was significantly higher in the coastal areas. The incidence rate in 2007 was higher for men than for women, whereas the average growth of the incidence was higher among women. CONCLUSION: This study shows that another important aspect regarding sun exposure, apart from latitude, is whether an area lies in the inland or on the coast. The higher sun exposure on the coast is associated with higher incidence of SCC. Preventive actions are needed; and perhaps extra information should be given to people living on the coast, who have a higher sun exposure.

Acute confusional state in elderly orthopaedic patients: factors of importance for detection in nursing care.

OBJECTIVES: The aims of this study were to identify factors of significance in the development of acute confusional state (ACS) and the differences between patients who developed ACS and those who did not. METHOD AND RESULTS: Assessment, observations and interviews with 505 patients admitted to an orthopaedic clinic revealed that 51 patients developed ACS during their in-hospital stay. Patients admitted for hip fracture had a higher incidence of ACS (20.2%) than patients admitted for elective surgery for coxarthros or gonarthros (3.6%). The highest hazard ratio for ACS was several other physical diseases 15.94 (CI: 4.60-55.31 and p-value <0.00001) and the lowest was age 1.10 (CI: 1.04-1.15 and p-value <0.0002). The ACS lasted from 1 to 9 days, and patients had one (N=42), two (N=8) or three episodes (N=1) of confusion during their stay on the ward. More patients who developed ACS before surgery had two or more confusional episodes and emergency patients developed ACS more rapidly. The ACS lasted longer in patients with a higher score on the OBS scale at admittance and with rapid development of ACS. CONCLUSIONS: Acuteness in the situation seems an important risk indication for ACS in the elderly. Awareness of factors associated with the development of ACS makes it possible to more systematically identify those at risk, for instance by systematic assessment in the first interview with the patient on admission to hospital.

Reactions from rat gastric mucosa during one year of Helicobacter pylori infection.

The aim of the present study was to investigate responses from the gastric mucosa of rats during long-term H. pylori infection. Twenty-four Sprague-Dawley rats were inoculated with a mouse-adapted strain of human H. pylori (vacA+, cagA+), 16 uninfected rats served as controls. Three to six rats from each group were killed two weeks or two, six, or 12 months later. At sacrifice, blood was sampled and the gastric mucosa was taken for bacterial culture, histology, immunocytochemistry and in situ hybridization. H. pylori colonized the antrum in 23/24 inoculated rats; with time the density of bacteria increased. The inflammation in the antral mucosa was mild to moderate and was dominated by infiltration of lymphocytes and macrophages. Serum H. pylori-specific IgG2a was significantly increased in the infected rats. The frequency of epithelial cell apoptosis was significantly increased in the early months of infection. The mucosal expression of trefoil peptide mRNA remained unchanged. We conclude that after one year of H. pylori infection in rats, the mucosal responses were rather mild, indicating that the animals may adapt to the infection by mechanisms which remain to be identified.