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[en] A technique to determine radiactivity in nasal swabs to control exposed workers was developed. The decision level was fixed at 200 pCi. The method proved fast and cheap. The technique allow, in a high percentage, preventing more expensive and troublesome analysis to the workers. (Author)
[en] Exposure limits for workers and the public are based on both chemical toxicity and radiation dose. As a consequence of the different procedures used in their calculation they are incompatible, and adherence to one limit may result in a serious breach of the other. This paper explores the background to these limits, the problems posed by their application and proposes how best to achieve compliance with both limits. (author)
[en] Various designs of inhalation chambers developed since the Manhattan Project are discussed. Essential features of current inhalation chambers are illustrated. It is stated that technology is available to control almost any variable in inhalation studies, although cost factors must be taken into consideration when experiments are designed
[en] In many types of surgery, especially orthopedic procedures, power tools such as saws and drills are used. These tools can impart considerable energy in disrupting tissue and may produce aerosolized blood and material from bone and other tissues. Surgical lasers and electrocautery tools can also produce aerosols due to vaporization of blood and tissues. A number of studies have been reported concerning production of aerosols during surgery, and some of the aerosols produced may contain infectious materials. Health care workers have expressed concern and questions pertaining to the occupational transmission of blood-borne pathogens including the human immunodeficiency virus (HIV) and hepatitis B virus (HBV) via blood aerosols during surgery. Little or no data existed characterizing the aerosols produced performing surgical procedures. Because of this lack of data, the National Institute for Occupational Safety and Health funded a project at ITRI to assess the extent of aerosolization of blood and other tissues during surgical procedures in the laboratory and in a hospital surgical suite
[en] The results of workers' exposure to mineral dust containing thorium and uranium, in two Brasilian mine and processing plant, are shown. The mineral dust samples were collected using a personal sampler and a cascade impactor. The faces samples were analysed to estimate the workers' incorporation. At installation A 232 Th concentration in the respirable fraction of aerosol are lower then detection limit (1 mBq/m3) and the 232 Th concentration in faces are in range of detection limit up to 23 mBq/g. At installation B the mineral dust samples were collected with a cascade impactor to determine the MMAD (Mass Median Aerodynamic Diameter) and the elemental mass concentration. The particles containing Nb, Th, U Sr, Zr and Y are in the respirable fraction of aerosol. The particle size are in the range of 1,6 up to 2,2 μm 232 Th in the respirable fraction of aerosol are lower then detection limit (1 mBq/m3) and the 232 Th concentration in faces are in range of detection limit up to 23 mBq/g. At installation B the mineral dust samples were collected with a cascade impactor to determine the MMAD (Mass Median Aerodynamic Diameter) and the elemental mass concentration. The particles containing Nb, Th, U, Sr, Zr and Y are in the respirable fraction of aerosol. The particle size are in the range of 1,6 up to 2,2 μm 232 Th in the respirable fraction are lower then detection limit. The 232 Th concentration in faeces are in range of detection limit up to 10,8 mBq/g. In both installations, incorporation occurs due mineral inhalation and ingestion. (author)
[en] Introduction: No model exists to describe the disposition and kinetics of inhaled cannabis containing a high THC dose. We aimed to develop a kinetic model providing estimates of the THC serum concentrations after smoking cannabis cigarettes containing high THC doses (up to 69 mg THC). Methods: Twenty-four male non-daily cannabis users smoked cannabis cigarettes containing 29.3 mg, 49.1 mg, and 69.4 mg THC. Blood samples were collected over a period of 0-8 h and serum THC concentrations were measured. A two-compartment open model was fitted on the individual observed data. Results: Large inter-individual variability was observed in the pharmacokinetic parameters. The median pharmacokinetic parameters generated by the model were Cmax = 175 ng/mL, Tmax = 14 min, and AUC0-8h = 8150 ng x min/mL for the 69.4 mg THC dose. Median model results show an almost linear dose response relation for Cmax/Dose = 2.8 x 10-6/mL and AUC0-8h/Dose = 136 x 10-6 min/mL. However, for increasing dose level, there was a clear decreasing trend: Cmax/Dose = 3.4, 2.6 and 2.5 x 10-6/mL and AUC0-8h/Dose = 157, 133 and 117 x 10-6 min/mL for the 29.3, 49.1 and 69.4 mg dose, respectively. Within the restriction of 8 h of observation, the apparent terminal half life of THC was 150 min. Conclusion: The model offers insight into the pharmacokinetics of THC in recreational cannabis users smoking cannabis containing high doses of THC mixed with tobacco. The model is an objective method for providing serum THC concentrations up to 8 h after smoking cannabis with a high THC content (up to 23%).
[en] Pneumatosis intestinalis is a rare disease with variable presentation. It is characterized by presence of gas in the gut wall. It may be primary (idiopathic) or secondary to other diseases. In the absence of signs and symptoms of perforation and peritonitis, pneumatosis intestinalis can be managed conservatively with inhaled oxygen and close monitoring of the patient. We present a case of 62 years old lady with this condition who was successfully treated with oxygen therapy. (author)
[en] Ethyl-N-(2-hydroxyethyl)-perfluorooctanesulfonamide (EtFOSE) was one of the key building blocks for many of the perfluorooctanesulfonyl-based chemistry and laboratory studies have shown that EtFOSE can metabolically degrade to perfluorooctanesulfonate (PFOS). Non-occupational contribution sources to PFOS are thought to occur in general population via diets, drinking water, air and dust. For workers, however, the exposure route was mostly airborne and the exposure source was predominantly to precursor compounds such as EtFOSE. We undertook this study to investigate how much EtFOSE was converted to PFOS in the serum for male rats after 6 h of exposure to EtFOSE vapor (whole body) at ambient temperature, which simulated a work place exposure scenario. There were no abnormal clinical observations and all rats gained weight during study. Interim tail-vein blood samples, collected up to 21 days after exposure, were analyzed for Et-FOSE and PFOS concentrations by LC-MS/MS. Upon inhalation exposure, the biotransformation of EtFOSE to PFOS in serum in the male rats was rapid and very little EtFOSE was detected in the serum within 24 h after EtFOSE exposure. The highest conversion to PFOS in serum after exposure to EtFOSE vapor appeared to occur between Day 8−14 post exposure. Considering the potential surface and fur adsorption of test compound in the whole-body exposure system, our data would support that at least 10% of the inhaled EtFOSE was biotransformed to PFOS in the serum based on the range of lower 95% CI (confidence interval) values. This information is valuable because it quantitatively translates EtFOSE exposure into serum PFOS concentration, which serves as a matrix for internal dosimetry (of PFOS exposure) that can be used as an anchor across species as well as between different exposure routes. - Highlights: • First inhalation study reported in rats that investigates the conversion of a major precursor compound (EtFOSE) to form PFOS. • Systemic absorption of EtFOSE in rats can occur upon inhalation exposure. • Our data suggest that at least 10% of the inhaled EtFOSE can be biotransformed to PFOS in the serum.
[en] We have developed an autoradiographic method to provide representative images of dose rate and dose distribution in the lungs after actinide oxide inhalation. This was based on the study of 30 μm thick dry sections obtained from 200 μm thick cryostat sections. In this case, solid track detector had a recording yield similar to that obtain for 5 μm thin sections and the resolution was less than 90 μm. Using this method, we visualized a heterogeneous particle distribution as soon as 3 months after exposure of rats to (U, Pu)O2 aerosols. (authors)