Occupational exposure to acrylamide in closed system production plants: air levels and biomonitoring.

The aim of this study was to evaluate biomarkers of acrylamide exposure, including hemoglobin adducts and urinary metabolites in acrylamide production workers. Biomarkers are integrated measures of the internal dose, and it is total acrylamide dose from all routes and sources that may present health risks. Workers from three companies were studied.

Male adolescent exposure to endocrine-disrupting pesticides: vinclozolin exposure in peripubertal rabbits.

Adolescence is a time of dramatic neuroendocrine changes that are required for sexual maturation. Hormonal mimicking or inhibiting chemicals can cause significant impairment during this critical period. Vinclozolin (Vin) has been shown to be an anti-androgen affecting male offspring in rats in utero, and its mechanism of action may be mediated by inhibition of androgenic receptor action.

Prioritization of NTP reproductive toxicants for field studies.

Population studies that evaluate human reproductive impairment are time consuming, expensive, logistically difficult, and with limited resources must be prioritized to effectively prevent the adverse health effects in humans. Interactions among health scientists, unions, and industry can serve to identify populations exposed to potential hazards and develop strategies to evaluate and apply appropriate controls. This report describes a systematic method for prioritizing chemicals that may need human reproductive health field studies.

Alterations in rabbit kidney protein expression following lead exposure as analyzed by two-dimensional gel electrophoresis.

It was recently reported that low blood lead levels impaired kidney function in men. To develop a set of molecular markers of renal lead exposure and effect, we investigated changes in renal protein expression while approximating occupational lead exposure at subchronic, low blood levels. Lead was administered to male Dutch Belted rabbits as a lead acetate solution adjusted weekly to achieve and maintain the target blood lead levels of 0, 20, 40, and 80 microg/dL for 15 weeks.

Male reproductive effects of lead, including species extrapolation for the rabbit model.

The effects of elevated blood lead on semen quality were evaluated in the rabbit model and compared to published effects in humans. Mature, male rabbits were given lead acetate by subcutaneous injection in the dose range of 0 to 3.85 mg/kg on a Monday-Wednesday-Friday basis.

Two-dimensional electrophoretic analysis of myocardial proteins from lead-exposed rabbits.

Despite reported adverse effects, the cardiovascular toxicity of lead remains controversial. The purpose of the present study was to determine if low-level subchronic exposure of rabbits to lead would produce detectable, concentration-dependent changes in myocardial proteins. Lead was administered to male Dutch Belted rabbits as a lead acetate solution, adjusted weekly to achieve and maintain the target blood lead levels of 0, 20, 40, and 80 microg/dL for 15 weeks.

Paternal exposure of rabbits to lead: behavioral deficits in offspring.

Paternal exposures to exogenous agents have been reported to produce a variety of developmental defects in the offspring. In experimental animals, these effects include decreased litter size and weight, increased stillbirth and neonatal death, birth defects, tumors, and functional/behavioral abnormalities-some of these effects being transmitted to the second and third generations. The majority of experimental studies assessing nervous system function of offspring following paternal exposures have utilized rats as the experimental animal, but other species can be used.

Review of experimental male-mediated behavioral and neurochemical disorders.

Paternal exposures to exogenous agents have been reported to produce a variety of developmental defects in the offspring. In experimental animals, these effects include decreased litter size and weight, increased stillbirth and neonatal death, birth defects, tumors, and functional/behavioral abnormalities-some of these effects being transmitted to the second and third generations. This article reviews the exogenous agents that have reportedly caused behavioral or neurochemical alterations in offspring of experimental animals following paternal exposures, including advanced age, alcohols, cyclophosphamide, ethylene dibromide, lead, opiates, and a few miscellaneous chemicals.

Fibrogenic potentials of coal slags used as abrasive blasting substitutes.

This study was designed to examine the fibrogenic potentials of four coal slags that are being used as substitutes for silica sand in abrasive blasting. Six groups of 100 male Sprague-Dawley rats, including four coal slag groups, a vehicle control, and a positive control for fibrosis (Minusil quartz), were used. Each dust treatment group was given a single 40-mg dose of test agent via intratracheal instillation.

Induction of sister chromatid exchange in spleen and bone marrow cells of rats exposed by inhalation to different dose rates of ethylene oxide.

We investigated the effects of dose rate on the frequency of sister chromatid exchange (SCE) in bone marrow and spleen cells of rats exposed to ethylene oxide (EtO). Four groups (18/group) of male Fischer 344 rats were exposed to EtO by inhalation. The exposures consisted of 100 ppm for 6 hr/day, 300 ppm for 2 hr/day, 600 ppm for 1 hr/day, and clean air control.

Pulmonary reactivity to vanadium pentoxide following subchronic inhalation exposure in a non-human primate animal model.

An experimental study was conducted to evaluate changes in pulmonary reactivity resulting from repeated vanadium pentoxide (V2O5) dust inhalation. The study assessed pulmonary reactivity to V2O5 through the use of provocation challenges, and compared V2O5 reactivity before and after subchronic V2O5 exposure. A total of 24 adult, male cynomolgus monkeys (Macaca fascicularis) were exposed by inhalation for 6 h per day, 5 days per week, for 26 weeks.

Evaluation of the onset and duration of response to cold air inhalation challenge in cynomolgus monkeys (Macaca fascicularis).

Cold air inhalation challenge (CAIC) for the evaluation of bronchial reactivity has been proposed as a physical agent alternative to chemical agent challenges (methacholine or histamine), especially suitable for the occupational environment. The present investigation describes and evaluates a method for performing cold air inhalation challenge in Cynomolgus monkeys (Macaca fascicularis), a species shown to be useful in animal modeling studies of occupational asthma. Six adult male anesthetized monkeys were ventilated by changes in external pressure while breathing cold air (-25 degrees C to -30 degrees C).

Subchronic inhalation of triethylamine vapor in Fischer-344 rats: organ system toxicity.

Male and female F-344 rats were exposed at 0, 25, or 247 ppm triethylamine (TEA) vapor, 6 hr per day, 5 days per week for up to 28 weeks in order to characterize the subchronic organ system toxicity. Rats were weighed biweekly and scheduled sacrifices were performed following about 30, 60, and 120 days of exposure. No statistically significant treatment-related effects on organ weights, hematology, clinical chemistry, or electrocardiographic indices were observed.

Acute airway narrowing in monkeys from challenge with 2.5 ppm formaldehyde generated from formalin.

Nine adult male Cynomolgus monkeys (Macaca fascicularis) were exposed for 10 min to 2.55 +/- 0.03 ppm formaldehyde (HCHO; mean +/- standard error of the mean, SEM) generated from formalin with a newly developed HCHO challenge system.

Immune responses of cynomolgus monkeys to phthalic anhydride.

Four groups of four Macaca fascicularis monkeys were administered 10 consecutive weekly subcutaneous injections of 2 mg aluminum hydroxide plus one of the following: 200 micrograms of phthalic anhydride (PA)-monkey serum albumin (PA-MSA, group 1); 200 micrograms of PA dissolved in ethanol-saline (EtOH-sal, group 2); 200 micrograms of MSA (group 3); or EtOH-sal alone (group 4). Direct intracutaneous tests to PA-MSA, PA-EtOH-sal, MSA, and EtOH-sal were applied at biweekly intervals throughout the course of the immunization. Serum-specific IgG to PA-MSA and specific IgE to PA-MSA were determined at 2-week intervals according to the ELISA and RAST methods, respectively.

Ozone enhancement of platinum asthma in a primate model.

Three groups of adult male cynomolgus monkeys (Macaca fascicularis) were exposed to either 200 micrograms/m3 ammonium hexachloroplatinate [(NH4)2PtCl6], 200 micrograms (NH4)2PtCl6 concurrently with 1 ppm ozone (O3), or to 1 ppm O3 only. The animals were exposed by inhalation for 6 h per day, 5 days per week for 12 wk. The experimental design included methacholine preexposure and Na2PtCl6 bronchoprovocation challenge evaluations, Na2PtCl6 threshold skin tests, and sera for analyses of antibodies.

Subchronic inhalation of diethylamine vapor in Fischer-344 rats: organ system toxicity.

Male and female Fischer 344 (F-344) rats were exposed at 0,25 or 250 ppm diethylamine (DEA) vapor, 6.5 hr per day, 5 days per week, for 24 weeks in order to assess cardiac and other organ system toxicity. Scheduled sacrifices were performed following 30, 60, and 120 days of exposure.

Pulmonary function analysis in the rabbit following bronchochallenge to causative agents and mediators of the acute byssinotic response.

New Zealand White rabbits were acutely bronchochallenged for 5 min to ascertain airway responsiveness with six potential byssinogenic agents and mediators: 0.1 g/mL cotton dust extract (CDE), 0.1 g/mL cotton bract extract (CBE), 1 mg/mL endotoxin, 1 mg/mL n-formyl methionyl peptide (n-fMet), 10 mg/mL 5-hydroxytryptamine (5-HT), and 1 mg/mL prostaglandin F2 alpha (PGF2 alpha).

Analysis of emissions collected from four types of iron casting molds.

The levels of polycyclic aromatic hydrocarbons (PAH) and related compounds, phenols and particulates were determined in emissions collected from iron casting molds composed of four different types of chemical binders: furan, urethane, green sand with sea coal and phenol-formaldehyde resins in shell molds. The shell sample, with 50% particulates, contained the most water-soluble material; green sand, 25% particulates; furan, 10% particulates; and urethane, less than 2% particulate material. The portion of the particulate fraction soluble in cyclohexane varies from 16 to 36% between mold types; emissions from urethane and furan molds contained the lowest quantities of cyclohexane-soluble components and of PAH and related compounds.

Pulmonary effects of acute vanadium pentoxide inhalation in monkeys.

An experimental study was conducted to investigate the hypothesis that changes in pulmonary function induced by vanadium pentoxide (V2O5) inhalation would be accompanied by evidence of pulmonary inflammation. Sixteen adult, male cynomolgus monkeys were acutely exposed by whole-body inhalation of V2O5 dust at aerosol concentrations of 0.5 mg V2O5/m3 and 5.

The diversity of reaginic immune responses to platinum and palladium metallic salts.

As part of a National Institute for Occupational Safety and Health health hazards evaluation, workers employed in a precious metal refinery exposed to platinum (Pt), palladium (Pd), and other group VIII metallic salts were evaluated for direct skin test sensitivity to Pt. Current (107) and former (30) workers who quit or were discharged because of Pt-related health problems were prick tested with ammonium hexachloroplatinate ([NH4]2 PtCl6). Of the 107 currently exposed workers, 15 (14%) exhibited positive skin tests, as indexed by immediate reactivity at a dose of 10(-3) gm/ml or less.

Pulmonary function responses in cats following long-term exposure to diesel exhaust.

Long-term inhalation studies were carried out to evaluate the toxic pulmonary effects of diesel engine emissions. Cats were exposed for over 2 years to whole, diluted diesel exhaust at levels expected to produce frank toxic effects. During the first 61 weeks of exposure, the cats received exhaust having a particulate level of 6 mg m-3.

Effects of a two-year inhalation exposure of rats to coal dust and/or diesel exhaust on tension responses of isolated airway smooth muscle.

This study was performed to determine whether chronic inhalation exposure of rats to levels of coal dust (CD) and/or diesel exhaust (DE) similar to those experienced by underground miners affects the pharmacologic characteristics of the animal's airway smooth muscle. Animals were exposed for 2 yr to CD alone (2 mg/m3 of respirable particulates), DE alone (2 mg/m3 of respirable particulates), or CD and DE (CD + DE) in combination (1 mg/m3 CD plus 1 mg/m3 DE). Concentration-response relationships for tension changes induced with acetylcholine, 5-hydroxytryptamine, potassium chloride, and isoproterenol were assessed in vitro on isolated preparations of rat airway smooth muscle (trachealis).