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PubMed1995

Assessment of offspring development and behavior following gestational exposure to inhaled methanol in the rat.

The prospect of widespread human exposure associated with its use as an alternative fuel has sparked concern about the toxic potential of inhaled methanol (MeOH). Previous studies have revealed congenital malformations in rats following inhaled MeOH (Nelson et al. (1985). Fundam. Appl. Toxicol. 5, 727-736) but these studies did not include postnatal behavioral assessment. In the present study, pregnant Long-Evans rats were placed in exposure chambers containing 15,000 ppm MeOH or air for 7 hr/day on Gestational Days (GD) 7-19. The total alveolar dose of methanol was estimated at about 6.1 g/kg/day, for a total dose of about 42.7 g/kg for the entire study. Maternal body weights were recorded daily and blood methanol concentrations were determined at the end of exposure on GD 7, 10, 14, and 18. Following birth (Postnatal Day 0 [PND 0]), a number of tests were performed at various points in development, including: offspring mortality and body wt (PND 1,3), motor activity (PND 13-21, 30, 60), olfactory learning (PND 18), behavioral thermoregulation (PND 20-21), T-maze learning (PND 23-24), acoustic startle response (PND 24, 60), reflex modification audiometry (PND 60), pubertal landmarks (PND 31-56), passive avoidance (PND 72), and visual-evoked potentials (PND 160). Maternal blood MeOH levels, measured from samples taken within 15 min after removal from the exposure chamber, declined from about 3.8 mg/ml on the first day of exposure to 3.1 mg/ml on the 12th day of exposure. MeOH transiently reduced maternal body wt (4-7%) on GD 8-10, and offspring BW (5%) on PND 1. No other test revealed significant effects of MeOH. Prenatal exposure to high levels of inhaled MeOH appears to have little effect on this broad battery of tests beyond PND 1 in the rat.

Administration, Inhalation↗
PubMed2000

Occupational exposure to inhaled anaesthetics: a follow-up study on anaesthetists of an eastern European university hospital.

BACKGROUND: Although no dose-response relationship for the health risks associated with the occupational exposure to inhaled anaesthetics exists, public health authorities recommend threshold values. The aim of the present study was to assess if and to what extent these threshold values are exceeded in an eastern European university hospital before and after measures had been taken to reduce occupational exposure. METHODS: At nine workplaces occupational exposure of anaesthetists to nitrous oxide and halothane or isoflurane was measured by means of photoacoustic infrared spectrometry. The measurements were carried out in 1996 and were repeated in 1997 after the installation of active scavenging devices at five workplaces and an air-conditioning system at one workplace. RESULTS: Occupational exposure to nitrous oxide and halothane or isoflurane was lower in 1997 compared to 1996. In 1997 most of the nitrous oxide values still exceeded the threshold value of 100 ppm, whereas most of the halothane and isoflurane values were already below the threshold values of 5 ppm and 10 ppm in 1996. CONCLUSION: The measures taken were effective in reducing waste gas exposure. Nevertheless, further efforts are necessary, especially for nitrous oxide, to reach western European standards. These efforts comprise structural measures such as active scavenging devices and air-conditioning systems at all workplaces, the use of total intravenous anaesthesia, low-flow anaesthesia and an appropriate working technique.

Anesthesiology↗
PubMed2002

Effects of 1-bromopropane, 2-bromopropane, and 1,2-dichloropropane on the estrous cycle and ovulation in F344 rats.

The present study was performed to investigate comparatively the toxic effects of inhalation exposure of 1-bromopropane, 2-bromopropane, and 1,2-dichloropropane on reproductive physiology, particularly on the estrous cycle and spontaneous ovulation in female F344 rats. The rats received inhalation exposure to different halogenated propanes, and were exposed daily for 8 h throughout almost 3 weeks to 0,50,200 and 1000 ppm of 1-bromopropane or 2-bromopropane, or to 0,50,100 and 200 ppm of 1,2-dichloropropane. Throughout the exposure period of 1-bromopropane or 2-bromopropane, the ratio of the number of estrous cycle of 6 days or longer to the number of all cycles in both 1000 ppm groups were about two-fold the ratio in each control group, however, no significant difference was found between the ratios of exposed and control groups. The ratios of such long estrous cycles in groups exposed to 100 or 200 ppm of 1,2-dichloropropane were six- to seven-fold higher than that of the control group. These ratios in exposed rats differed significantly from those of controls. The number of ovulated ova in rats exposed to 1,2-dichloropropane decreased in a dose-dependent manner, and the number of ovulated ova in the 200 ppm group was significantly different from that of control rats. Such significant changes in ovulation were not observed in rats exposed to 1-bromopropane or 2-bromopropane. The absolute and relative weights of the ovaries and uterus in rats exposed to three halogenated propanes were not significantly different from those in each control. Therefore, the present study clarified that: (1) 1,2-dichloropropane prolonged the length of the estrous cycle and inhibited spontaneous ovulation in F344 rats; and (2) the potency of 1,2-dichloropropane to disturb the female reproductive physiology appeared to be greater compared with that of 1-bromopropane and 2-bromopropane under the present conditions of inhalation exposure.

Animals↗
PubMed1988

[Evaluation of occupational exposure to inhalation anesthetics. Study Group on Environmental Monitoring, Biological Monitoring and Laboratory Surveillance in Lombardia].

A group of Occupational Medicine researchers in Lombardia prepared a document about the problems of occupational exposure to inhalation anaesthetics referring to the Meeting "Occupational Hazard from Inhalation Anaesthetics. Monitoring and Prevention". (Pavia, May 1988). A survey in 111 operating theatres and 11 hospitals showed high anaesthetics pollution and allowed to find its main causes. On the basis of this survey the authors were able to indicate the methods to control the exposure, both by determining the polluting agents in working environment, and by using the internal dose biological monitoring. For the exposure monitoring the authors suggest determining nitrous oxide (N2O) in various sites of the operating rooms, in the operators respiratory zone and/or in single workers' urine at the end of the work-shift. The environmental and/or biological measurement of nitrous oxide also indicated the pollution due to other inhalation anesthetics used at the same time. The authors also make suggestions about the methods and timing of environmental and biological monitoring and health surveillance.

Air Pollutants, Occupational↗
PubMedDate not supplied

Circulating factors that modify lung cell DNA synthesis following exposure to inhaled oxidants. III. Effects of plasma on lung pneumocyte and fibroblast DNA synthesis following exposure of adult rats to 85% oxygen.

Previous studies, in which adult rats were exposed to 1 ppm ozone for 2 weeks, demonstrated the appearance in plasma of separate factors that stimulated DNA synthesis by cultured pneumocytes and lung fibroblasts in a dose-dependent and cell-specific fashion. Both factors had isoelectric points of 6.45-6.75, but differed by molecular mass. The pneumocyte factor had an estimated weight of 38 +/- 3 kDa, while the fibroblast factor had an estimated molecular weight of 32 +/- 2 kDa. To determine whether the appearance of these factors in plasma is specific for ozone injury or whether they appear in response to other oxidant injuries, adult rats were exposed to 85% O2 or air for up to 2 weeks. Animals were sacrificed at 3, 5, 7, or 14 days after the onset of exposure. Plasma samples were subjected to sequential preparative electrofocusing and high-performance liquid chromatography (HPLC). Heat-inactivated plasma fractions, with an isoelectric point of 6.45-6.75, contained a factor of 32 +/- 2 kDa, which enhanced lung fibroblast DNA synthesis at a single time point on day 5 of 85% O2 exposure, and a factor of 38 +/- 3 kDa, which enhanced pneumocyte DNA synthesis on days 5, 7, and 14 of 85% O2 exposure. Of the known growth factors, those most likely to have these physical characteristics are platelet-derived growth factor (PDGF) and insulin-like growth factor-1. Additional groups of animals were exposed to air or 85% O2 for 5 days for plasma collection. Animals exposed to 85% O2 had a 60% increase of plasma immunoreactive PDGF and a 90% increase of plasma immunoreactive IGF-1, compared with values for control animals exposed to air.

Administration, Inhalation↗
PubMed2004

Experimental human exposure to inhaled grain dust and ammonia: towards a model of concentrated animal feeding operations.

BACKGROUND: Ammonia and endotoxin-rich dust are present in high concentrations in swine confinement facilities; exposure to this environment is linked to workers' respiratory problems. We hypothesized that experimental exposure to ammonia and dust would impair pulmonary function, and that these exposures would be synergistic. METHODS: We exposed six normal subjects and eight subjects with mild asthma to ammonia (16-25 ppm) and/or endotoxin-rich grain dust (4 mg/m3). Pulmonary function and exhaled NOx were measured before and after exposure. RESULTS: There was no significant change in pulmonary function in the normal subjects following any of the exposure conditions. Among asthmatics, a significant transient decrease in FEV1 was induced by grain dust, but was not altered by ammonia; increased bronchial hyperreactivity was also noted in this group. CONCLUSION: In a vulnerable population, exposure to grain dust results in transient airflow obstruction. Short-term exposure to ammonia does not increase this response.

Adult↗
PubMed2000

Pharmacological evaluation of aerosolized cannabinoids in mice.

The reemergence on the debate of the use of marijuana for medicinal purposes has been the impetus for developing an acceptable delivery form of aerosolized cannabinoids. The goals of the present study were to: (1) develop and characterize the physical properties of an aerosolized form of Delta(9)-tetrahydrocannabinol (Delta(9)-THC), the major psychoactive constituent present in marijuana; and (2) assess the pharmacological effects of cannabinoid inhalation in mice. A Small Particle Aerosol Generator (SPAG) nebulizer, used to generate the aerosol, had an output of approximately 0.154 mg/l of aerosolized Delta(9)-THC with a 2.0 microm mass median aerodynamic diameter and a 2.2 geometric standard deviation (GSD). Virtually all the particles were less than 5.0 microm in diameter suggesting that they were sufficiently small to penetrate deeply into the lungs. Inhalation exposure to aerosolized Delta(9)-THC in mice elicited antinociceptive effects that were dependent on concentration and exposure time with an estimated Delta(9)-THC dose of 1.8 mg/kg. On the other hand, inhalation exposure to Delta(9)-THC failed to produce two other indices indicative of cannabinoid activity, hypothermia and decreases in spontaneous locomotor activity. The antinociceptive effects occurred within 5 min of exposure and lasted approximately 40 min in duration. The cannabinoid receptor antagonist N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2, 4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide HCl (SR 141716A), but not naloxone, blocked these antinociceptive effects (AD(50)=0.09 mg/kg) indicating a cannabinoid receptor mechanism of action. Similarly, inhalation exposure to a water soluble cannabinoid analog, 3-(5'-cyano-1', 1'dimethylheptyl)-1-(4-N-morpholinobutyrloxy)-Delta(8)-te trahydrocann abinol (O-1057), produced antinociception that was blocked by SR 141716A. These results demonstrate that the development of an aerosolized form of cannabinoids for human medicinal use is feasible.

Administration, Inhalation↗
PubMed1988

Mechanisms of neutrophil recruitment to the lung by grain dust exposure.

Inhalation of grain dusts can cause symptoms of both acute and chronic bronchitis, which has been associated with a neutrophilic inflammatory response in the lung. Since this influx of neutrophils may potentially result in bronchial injury, mechanisms of neutrophil recruitment to grain dust were examined. Sterile, aqueous grain dust extracts were prepared from settled dusts of grain sorghum, corn, oats, and soybeans. The extracts were evaluated for their ability to directly attract human neutrophils using a blindwell neutrophil chemotaxis assay. Each extract was found to possess significant chemotactic activity compared to control (p less than 0.01). To evaluate if the dusts could attract neutrophils indirectly by activating humoral inflammatory mechanisms, the grain dust extracts were evaluated for their ability to activate the complement system. When incubated with normal human serum, each of the grain dusts caused cleavage of the complement proteins C3 and properdin factor B (PFB). Importantly, the grain dust extracts lead to the generation of C5a, a potent neutrophil chemoattractant generated by complement activation. Since activation of the alveolar macrophage to release chemotactic activity represents an additional indirect mechanism of neutrophil recruitment, an extract from grain sorghum dust was evaluated for its ability to stimulate guinea pig and human alveolar macrophages to release neutrophil chemotactic activity. The results demonstrate that supernatants obtained from alveolar macrophages cultured in the presence of grain sorghum dust extract possessed increased chemotactic activity compared to controls (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗
PubMedDate not supplied

One-month exposure to inhaled endotoxin produces a dose-dependent increase in stored mucosubstances in rat intrapulmonary airways.

This study examined the production of stored mucosubtances in rats after repeated exposure to aerosolized endotoxin, a common contaminant of bioaerosols. Male Fischer 344 rats were exposed to aerosolized saline (sham control) or endotoxin (target concentrations of 0.05, 0.5, and 5.0 micrograms/m3) for 3 h/day, 5 days/week for 4 weeks. Following the final exposure, the left lung of each animal was lavaged and the right lung and nasal cavity were fixed with buffered formalin. Morphometric examination of Alcian blue/Periodic acid Schiffs-stained (AB/PAS) lung sections demonstrated dose-dependent increases in stored intraepithelial mucosubstances in the intrapulmonary airways of endotoxin-exposed rats. Threefold and eightfold increases in stored mucosubstances were observed in generation 5 airways of animals exposed to 0.5 or 5.0 microgram/m3 endotoxin, respectively (p < .05). This mucous cell metaplasia in the intrapulmonary airways was not accompanied by evidence of lung inflammation or increased AB/PAS-staining high molecular weight material in lavage fluid. Furthermore, despite significant deposition of endotoxin aerosols (mass median aerodynamic diameter of 1.9 microns) in the nasal cavity, no significant changes in stored mucosubstances were observed in the nasal septum. In animals repeatedly exposed to 5.0 micrograms/m3 endotoxin and allowed to recover for 1 month, stored mucosubstances in the intrapulmonary airway were still more than fivefold greater than control values. Thus, in rats, repeated exposure to inhaled endotoxin produced a persistent mucous cell metaplasia only in the intrapulmonary airways.

Administration, Inhalation↗
PubMed2005

Beryllium exposure: dermal and immunological considerations.

OBJECTIVE: People exposed to beryllium compounds are at increased risk of developing beryllium sensitization and chronic beryllium disease (CBD). The purpose of this short communication is to present information regarding the potential importance of skin exposure to beryllium, an exposure and alternate immune response pathway to the respiratory tract, which has been largely overlooked in epidemiologic and exposure assessment studies. METHODS: We reviewed the published literature, including epidemiologic, immunologic, genetic, and laboratory-based studies of in vivo and in vitro models, to assess the state of knowledge concerning skin exposure to beryllium. RESULTS: Reduction in inhalation exposure to beryllium has not resulted in a concomitant reduction in the occurrence of beryllium sensitization or CBD, suggesting that continued prevalence may be due, in part, to unchecked skin exposure to beryllium-containing particles. CONCLUSIONS: Recent developments in our understanding of the multiple exposure pathways that may lead to beryllium sensitization and CBD suggest that a prudent approach to worker protection is to assess and minimize both skin and inhalation exposures to beryllium.

Berylliosis↗
PubMed1993

Metabolic fate and disposition of 1,1,1,2-tetrafluoroethane (HFC134a) in rat following a single exposure by inhalation.

1. The metabolic fate and disposition of [U-14C]-1,1,1,2-tetrafluoroethane ([U-14C]-HFC134a) has been determined in the male and female rat following a 1 h single exposure by inhalation to atmospheres of 10,000 ppm. 2. Of the inhaled dose, approx. 1% was recovered in urine, faeces and expired air postexposure indicating that absorption of this fluorocarbon across the lung is poor. Of this 1%, approx, two-thirds were exhaled within 1 h of the cessation of exposure as unchanged HFC134a. The remaining radioactivity was exhaled as [14C]-carbon dioxide or excreted in urine and faeces as trifluoroacetic acid. 3. Carbon dioxide was the major metabolite of HFC134a accounting for 0.22 and 0.27% of the inhaled dose in the male and female rat, respectively. Urinary excretion accounted for 0.09% of the dose and faecal excretion 0.04% of the dose by both sexes. 4. Total metabolism measured as the sum of the radioactivities in urine, faeces and as carbon dioxide amounted to 0.34 and 0.40% of the inhaled dose in male and female, respectively. 5. There were no major sex differences in the rates, routes or amounts of radiolabel excreted. Analysis of a range of tissues at 5 days postexposure showed a relatively uniform distribution of radioactivity. There was no evidence for a specific uptake of HFC134a or a metabolite into any organ or tissue analysed, including fat.

Absorption↗
PubMed1994

Development of a physiologically based pharmacokinetic model for perchloroethylene using tissue concentration-time data.

The tissue disposition of perchloroethylene (PCE) was characterized experimentally in rats in order to (1) obtain input parameters from in vivo data for the development of a physiologically based pharmacokinetic (PBPK) model, and (2) use the PBPK model to predict the deposition of PCE in a variety of tissues following inhalation exposure. For the derivation of model input parameters, male Sprague-Dawley rats received a single bolus of 10 mg PCE/kg body wt in polyethylene glycol 400 by ia injection through an indwelling carotid arterial cannula. Other male Sprague-Dawley rats inhaled 500 ppm PCE for 2 hr in dynamic exposure inhalation chambers. Serial samples of brain, liver, kidney, lung, heart, skeletal muscle, perirenal fat, and blood were taken for up to 72 hr following ia injection, during the 2-hr inhalation exposure, and for up to 72 hr postexposure. Blood and tissue PCE concentrations were analyzed using a gas chromatography headspace technique. Following ia administration, the tissues exhibited similar terminal elimination half-lives (t1/2). As comparable tissue t1/2 are consistent with a blood-flow-limited model, tissue:blood partition coefficients were calculated for noneliminating compartments by division of the area under the tissue concentration-time curve (AUC) by the blood AUC. Liver PCE concentration versus time data were employed in the calculation of in vivo metabolic rate constants. A PBPK model was developed using these parameters derived from the ia data set and used to predict tissue PCE concentrations during and following PCE inhalation. Predicted tissue levels were in close agreement with the levels measured over time in the seven tissues and in blood. Tissue concentration-time data can thus provide valuable input for parameter estimation and for validation of PBPK model simulations, as long as independent in vivo data sets are used for each step.

Administration, Inhalation↗
PubMed1993

A proposal for improving the role of exposure modeling in risk assessment.

This paper explores the adequacy of using currently available exposure assessment models for indoor air inhalation exposures in the context of the uncertainty that exists in both the dose-response assessment and the exposure assessment. A tiered system is proposed for implementing exposure assessments. Each tier involves additional research, but also would lead to reductions in uncertainty. The authors discuss a possible comprehensive research program that will permit the building of well-validated models for indoor air inhalation exposures among classes of chemicals, building types, and exposure scenarios. The authors believe that until such a research program is undertaken, modeling of exposures (and therefore risks) using the current, unvalidated modeling approaches provides little more than worst-case estimates that are useful primarily for making screening decisions about risks.

Air Pollution, Indoor↗
PubMed2005

The risk of nonvertebral fracture related to inhaled corticosteroid exposure among adults with chronic respiratory disease.

OBJECTIVE: To examine nonvertebral fracture risk in relation to inhaled corticosteroid (ICS) exposure among adults with respiratory disease. DESIGN AND PATIENTS: Nested case-control study within a cohort of 89,877 UnitedHealthcare members aged > or = 40 years with physician insurance claims for COPD or asthma, enrolled for > or = 1 year from January 1, 1997 to June 30, 2001. METHODS: Cases (n = 1,722) represented patients with a first treated nonvertebral fracture (the index date is the first fracture claim). Control subjects (n = 17,220) were randomly selected from the person-time and assigned a random index date. ICS exposure was ascertained 1 month, 3 months, 6 months, and 12 months before the index date, with estimated cumulative dose through 0 to 6 months, 7 to 12 months, and 0 to 12 months. Covariates included demographics, oral corticosteroid and other medication exposure, comorbidities, and indicators of respiratory disease severity. Odds ratios (ORs) adjusted for all covariates were estimated by logistic regression. RESULTS: No increased fracture risk with ICS exposure as a class or with fluticasone propionate alone was detected. ORs for exposure in the preceding 30 days were 1.05 (95% confidence interval [CI], 0.89 to 1.24), 1.13 (95% CI, 0.90 to 1.40), and 0.97 (95% CI, 0.78 to 1.21) for all ICS, fluticasone propionate, and other ICS, respectively. No dose-response effect was present. Among patients with COPD only (n = 6,932), no increased risk was found for recent ICS exposure (OR, 0.86; 95% CI, 0.59 to 1.25). CONCLUSIONS: Concern about nonvertebral fracture risk should not strongly influence the decision to use recommended doses of ICS for adult patients with asthma or COPD in managed-care settings in the United States. This study could not evaluate very-high ICS dose, long-term ICS exposure, or vertebral fracture risk.

Adult↗
PubMed2005

Developmental neurotoxicity study of styrene by inhalation in Crl-CD rats.

This study was conducted to assess potential adverse functional and/or morphological effects of styrene on the neurological system in the F2 offspring following F0 and F1 generation whole-body inhalation exposures. Four groups of male and female Crl:CD (SD)IGS BR rats (25/sex/group) were exposed to 0, 50, 150, and 500 ppm styrene for 6 hr daily for at least 70 consecutive days prior to mating for the F0 and F1 generations. Inhalation exposure continued for the F0 and F1 females throughout mating and through gestation day 20. On lactation days 1 through 4, the F0 and F1 females received styrene in virgin olive oil via oral gavage at dose levels of 66, 117, and 300 mg/kg/day (divided into three equal doses, approximately 2 hr apart). Inhalation exposure of the F0 and F1 females was re-initiated on lactation day 5 and continued through weaning of the F1 or F2 pups on postnatal day (PND) 21. Developmental landmarks were assessed in F1 and F2 offspring. The neurological development of randomly selected pups from the F2 generation was assessed by functional observational battery, locomotor activity, acoustic startle response, learning and memory evaluations, brain weights and dimension measurements, and brain morphometric and histologic evaluation. Styrene exposure did not affect survival or the clinical condition of the animals. As expected from previous studies, slight body weight and histopathologic effects on the nasal olfactory epithelium were found in F0 and F1 rats exposed to 500 ppm and, to a lesser extent, 150 ppm. There were no indications of adverse effects on reproductive performance in either the F0 or F1 generation. There were exposure-related reductions in mean body weights of the F1 and F2 offspring from the mid and high-exposure groups and an overall pattern of slightly delayed development evident in the F2 offspring only from the 500-ppm group. This developmental delay included reduced body weight (which continued through day 70) and slightly delayed acquisition of some physical landmarks of development. Styrene exposure of the F0 and F1 animals had no effect on survival, the clinical condition or necropsy findings of the F2 animals. Functional observational battery evaluations conducted for all F1 dams during the gestation and lactation periods and for the F2 offspring were unaffected by styrene exposure. Swimming ability as determined by straight channel escape times measured on PND 24 were increased, and reduced grip strength values were evident for both sexes on PND 45 and 60 in the 500-ppm group compared to controls. There were no other parental exposure-related findings in the F2 pre-weaning and post-weaning functional observational battery assessments, the PND 20 and PND 60 auditory startle habituation parameters, in endpoints of learning and memory performance (escape times and errors) in the Biel water maze task at either testing age, or in activity levels measured on PND 61 in the 500-ppm group. Taken together, the exposure-related developmental and neuromotor changes identified in F2 pups from dams exposed to 500 ppm occurred in endpoints known to be both age- and weight-sensitive parameters, and were observed in the absence of any other remarkable indicators of neurobehavioral toxicity. Based on the results of this study, an exposure level of 50 ppm was considered to be the NOAEL for growth of F2 offspring; an exposure level of 500 ppm was considered to be the NOAEL for F2 developmental neurotoxicity.

Animals↗
PubMed2000

Mechanisms of toxicity, clinical features, and management of acute chlorophenoxy herbicide poisoning: a review.

INTRODUCTION: Chlorophenoxy herbicides are used widely for the control of broad-leaved weeds. They exhibit a variety of mechanisms of toxicity including dose-dependent cell membrane damage, uncoupling of oxidative phosphorylation, and disruption of acetylcoenzyme A metabolism. Between January 1962 and January 1999, 66 cases of chlorophenoxy herbicide poisoning following ingestion were reported in the literature. FEATURES FOLLOWING INGESTION: Adjuvants in the formulations may have contributed to some of the features observed. Vomiting, abdominal pain, diarrhea, and, occasionally, gastrointestinal hemorrhage were early effects. When present, hypotension was predominantly due to intravascular volume loss, although vasodilation and direct myocardial toxicity may have contributed in some cases. Neurotoxic features included coma, hypertonia, hyperreflexia, ataxia, nystagmus, miosis, hallucinations, convulsions, fasciculation, and paralysis. Hypoventilation occurred not infrequently, usually in association with central nervous system depression, but respiratory muscle weakness was a factor in the development of respiratory failure in some patients. Myopathic symptoms including limb muscle weakness, loss of tendon reflexes, and myotonia were observed and increased creatine kinase activity was noted in some cases. Other clinical features reported included metabolic acidosis, rhabdomyolysis, renal failure, increased aminotransferase activities, pyrexia, and hyperventilation. Twenty-two of 66 patients died. FEATURES FOLLOWING DERMAL AND INHALATIONAL EXPOSURE: Substantial dermal or inhalational 2,4-dichlorophenoxyacetic acid exposure has occasionally led to systemic features but no such reports have been published in the last 20 years and no fatalities have been reported at any time. Substantial dermal exposure has been reported to cause mild gastrointestinal irritation after a latent period followed by progressive mixed sensory-motor peripheral neuropathy. Mild, transient gastrointestinal and peripheral neuromuscular symptoms have also occurred after occupational inhalation exposure, with or without dermal exposure. MANAGEMENT: In addition to supportive care, alkaline diuresis to enhance herbicide elimination should be considered in all seriously poisoned patients. Limited clinical data suggest that hemodialysis produces similar herbicide clearance to alkaline diuresis without the need for urine pH manipulation and the administration of substantial amounts of intravenous fluid in an already compromised patient. CONCLUSIONS: While chlorophenoxy herbicide poisoning is uncommon, ingestion of a chlorophenoxy herbicide can result in serious and sometimes fatal sequelae. In severe cases of poisoning, alkaline diuresis or hemodialysis to increase herbicide elimination should be considered.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2005

Assessment of bioaerosols and inhalable dust exposure in Swiss sawmills.

An assessment of wood workers' exposure to airborne cultivable bacteria, fungi, inhalable endotoxins and inhalable organic dust was performed at 12 sawmills that process mainly coniferous wood species. In each plant, samples were collected at four or five different work sites (debarking, sawing, sorting, planing and sawing cockpit) and the efficiency of sampling devices (impinger or filter) for determining endotoxins levels was evaluated. Results show that fungi are present in very high concentrations (up to 35 000 CFU m(-3)) in all sawmills. We also find that there are more bioaerosols at the sorting work site (mean +/- SD: 7723 +/- 9919 CFU m(-3) for total bacteria, 614 +/- 902 CFU m(-3) for Gram-negative, 19 438 +/- 14 246 CFU m(-3) for fungi, 7.0 +/- 9.0 EU m(-3) for endotoxin and 2.9 +/- 4.8 g m(-3) for dust) than at the sawing station (mean +/- SD: 1938 +/- 2478 CFU m(-3) for total bacteria, 141 +/- 206 CFU m(-3) for Gram-negative, 12 207 +/- 10 008 CFU m(-3) for fungi, 2.1 +/- 1.9 EU m(-3) for endotoxin and 0.75 +/- 0.49 mg m(-3) for dust). At the same time, the species composition and concentration of airborne Gram-negative bacteria were studied. Penicillinium sp. were the predominant fungi, while Bacillus sp. and the Pseudomonadacea family were the predominant Gram-positive and Gram-negative bacteria encountered, respectively.

Aerosols↗
PubMedDate not supplied

Monitoring occupational exposure to inhalation anesthetics.

Air monitoring, an essential feature of the waste gas control program, is best based on measurement of total leakage in time-weighted sampling of N2O present in the anesthetist's breathing zone during clinical anesthesia. Leakage in the high-pressure N2O system is measured separately in a survey of the empty rooms. The infrared N2O analyzer used for these measurements is also useful as a teaching device and in enhancing the safety of the patient.

Air Pollutants↗