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Papers by Sidney Soderholm

Fundamental and applied toxicology, Nov 1, 1996

Although the acute toxicity of methanol is well documented, few studies have addressed the conseq... more Although the acute toxicity of methanol is well documented, few studies have addressed the consequences of perinatal exposures to the low concentrations that are expected to arise from its proposed use as a component of automobile fuel. This report describes the general research design of a series of studies, the effects of methanol exposures on blood concentrations in dams and neonates, and indices of brain development. Four cohorts of Long-Evans pregnant rats, each cohort consisting of an exposure (n = 12) and a control (n = 12) group, were exposed whole-body to 4500 ppm methanol vapor or air for 6 hr daily beginning on Gestation Day 6. Both dams and pups were then exposed through Postnatal Day 21 (PND 21). Blood methanol concentrations determined by gas chromatography from samples obtained immediately following a 6-hr exposure reached approximately 500-800 micrograms/ml in the dams during gestation and lactation. Average concentrations for pups attained levels about twice those of the dams. Selected offspring from Cohort 4 were exposed for one additional 6-hr session at ages that extended out to PND 52. Regression analyses showed that the blood methanol concentrations of the pups declined until about PND 48, at which time their levels approximated those of their dams. Such pharmacokinetic differences might increase the risks posed to developing organisms. Light-microscopic analysis showed no significant abnormalities in the brains of the methanol-treated animals. However, assays of neural cell adhesion molecules (NCAMs) in brains of pups sacrificed on PND 4 showed staining for both the 140 and the 180 kDa isoforms to be less intense in the cerebellum of exposed animals. NCAM differences were not apparent in animals sacrificed 15 months after their final exposure.

Journal of Aerosol Science, 1990

The purpose of our studies is to elucidate the basic mechanism of lung tissue injury which may be... more The purpose of our studies is to elucidate the basic mechanism of lung tissue injury which may be common for particles of high or low toxicity. In experiments on rats we compared particle translocation of two types of TiO 2 and of two types of Al 2 O 3 . The types of TiO 2 or Al 2 O 3 differ in origin, manufacturing technology and most importantly in the size of the primary particles, but not in chemical or crystallographic characteristics

CRC Press eBooks, Jul 28, 2017

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Journal of Applied Toxicology, Apr 1, 1981

A chronic inhalation exposure study was initiated to study the potential health effects of diesel... more A chronic inhalation exposure study was initiated to study the potential health effects of diesel exhaust on laboratory animals. Test atmospheres of clean air (control) or freshly diluted diesel exhaust at nominal particulate concentrations of 250, 750 and 1500 pg m-3 were supplied to four large volume inhalation chambers in which individually housed Fischer 344 albino rats (Rattus norvegicus) and Hartley guinea pigs (Cuviu porcellus) were exposed for 20 h per day, 5; days per week. The diesel aerosol concentration, chamber temperature and relative humidity were continually monitored and controlled to maintain the exposure dose levels and an environment of 22 f 2 OC and 50 f 20% relative humidity. Animals were randomly sampled from the chambers for physiological, biochemical and pathological studies throughout the exposure period. The study was continued without interruption for 24 months with the mean diesel particle mass concentrations within 6% of the target values. The standard deviation of the mass concentration measurements was approximately 30% of the mean.

A 1-year study of the model LAS-X (Particle Measuring Systems, Inc.) laser spectrometer in the De... more A 1-year study of the model LAS-X (Particle Measuring Systems, Inc.) laser spectrometer in the Department of Energy (DOE) Filter Test Facilities (FTFs) was begun on August 1, 1983. The principal objectives of the study were to gain operational experience with the LAS-X/diluter/HP-85 particle size measurement system in the FTF environment, acquire size distribution data to quantify the consistency of

The overall objective of this project was to evaluate alternative materials, devices, and procedu... more The overall objective of this project was to evaluate alternative materials, devices, and procedures that could improve performance test methods for high-efficiency particulate air (HEPA) filters and media and could lead to a new generation of quality assurance (QA) test equipment. Shortcomings of the current QA test equipment and procedures include the use of di-(2-ethylhexyl)phthalate (DEHP), a suspect carcinogen, and

OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), 1984

The dissolution behavior of settled and airborne uranium material produced by firing of depleted ... more The dissolution behavior of settled and airborne uranium material produced by firing of depleted uranium munitions was studied using an in vitro dissolution techniq ue. Differences in the composition of bulk and respirable fraction samples of these materials were observed. Dissolut i on analysis results suggest that under some conditions a rapidly dissolving uranill!l fraction may be fanned. This fraction may play an important role in determ i ning hazard potential assoc i ated with inhalation exposure to uranium materials. The fact that a larger rao i dly dissolving fractio n was observed in the airborne material than in the settled material i nd i cates that dissolution analysis should be perfonned on appropriate size fraction s1111o les.

Journal of Aerosol Science, 1991

Every high-efficiency aerosol filter used in United States Department of Energy (DOE) facilities ... more Every high-efficiency aerosol filter used in United States Department of Energy (DOE) facilities is quality assurance tested at one of the DOE filter test facilities before installation. This testing presently includes measurement of filter penetration at rated and 20%-rated airflow using a thermal-aerosol generator, an Owl aerosol size analyzer, and a scattered-light-photometer aerosol concentration monitor. Alternative penetration measurement methods for testing size 5 high-efficiency aerosol filters, which have rated airflow capacities of approx.28 m/sup 3//min (1000 ft/sup 3//min), were studied at Los Alamos National Laboratory. The methods studied take advantage of commercially available aerosol instrumentation and provide a more meaningful evaluation of the filters used in DOE facilities. A penetration test using a polydisperse aerosol, produced with a modified Laskin-nozzle aerosol generator, a laser aerosol spectrometer for aerosol size and concentration measurements, an aerosol diluter, and a microcomputer, is recommended as an alternative to the present test method. Such a test eliminates the difficulty in producing a monodisperse challenge aerosol, takes advantage of state-of-the-art aerosol sizing instruments, and can provide more detailed information regarding filter performance. Potential alternatives to di-(2-ethylhexyl)phthalate are also discussed. 86 refs., 38 figs., 5 tabs.

Journal of Aerosol Science, 1989

A monodisperse aerosol generator forms a stable jet of liquid at a velocity allowing columnar bre... more A monodisperse aerosol generator forms a stable jet of liquid at a velocity allowing columnar breakup into droplets of uniform size and spacing. To prevent degradation of the monodisperse aerosol; it is dispersed by 17 FIC12 * * * * *

Annals of Occupational Hygiene, 1994

The possibility of widespread methanol exposure via inhalation stemming from its adoption as an a... more The possibility of widespread methanol exposure via inhalation stemming from its adoption as an automotive fuel or fuel component arouses concerns about the potential vulnerability of the fetal brain. This project was designed to help address such concerns by studying the behavior of neonate and adult rats following perinatal exposure to methanol vapor. Four cohorts of pregnant Long-Evans hooded rats, each cohort consisting of an exposure and a control group, were exposed to 0 parts per million (ppm) (control) or 4,500 ppm methanol vapor for six hours daily beginning on gestation day (GD) 6 with dams and pups then being exposed postnatal day (PND) 21. Exposures took place in 2-m3 Rochester-type inhalation chambers while the animals remained in their plastic breeder cages. Prenatal and postnatal blood methanol concentrations were determined by gas chromatography. Blood methanol concentrations of the dams, measured immediately following a six-hour exposure, were approximately 500 to 800 micrograms/mL throughout gestation and lactation. Average blood methanol concentrations of the pups were about twice those of the dams. Because such results appeared consistently across the other cohorts, we decided to obtain additional data with Cohort 4. Once it had undergone the standard exposure protocol, we selected sets of extra pups from those that had not been assigned previously to the adult phase of behavioral testing. Each set was exposed once, at ages that extended out to PND 52, for one additional six-hour session of exposure to 4,500 ppm methanol. The blood methanol concentrations of these pups declined until about PND 48, at which time they approximated those of the dams. These findings might be accounted for by a process of metabolic maturation in the pups that remains to be identified.

Journal of Environmental Monitoring, 2005

A user-friendly environmental monitoring system that collects real time data has been developed. ... more A user-friendly environmental monitoring system that collects real time data has been developed. Flash card memory logs exposure data from multiple sensors along with corresponding times and positions. Optional use of telemetry repeaters and a reference station allows central monitoring of data to assess exposure and to initiate intervention when safe levels are exceeded. A software analysis package allows researchers to identify exposure hot spots and direct control efforts, with the ultimate goal being to reduce injury and disease. Preliminary field test results document position accuracy and system performance in harsh environments.