137 Matching Results

Search Results

Advanced search parameters have been applied.

in subjects: "Pathological Changes"

open access

Tumor production in Syrian hamsters following inhalation of PuO/sub 2/--ZrO/sub 2/ aerosol

Syrian golden hamsters of both sexes were exposed to aerosols of ZrO/sub 2/ containing PuO/sub 2/. The starting material in the aerosol generator also had a small amount of /sup 57/Co added as a tracer. The mixture of all three constituents was nebulized and the droplets passed through a heating column at 1000/sup 0/C. Aerosol sampling was accomplished with a cascade impactor and electrostatic precipitator. The median aerodynamic diameters in all inhalation runs were approximately 2 ..mu..m wit… more

Date: January 1, 1978

Creator: Thomas, R. G. & Smith, D. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Drug metabolizing enzyme systems and their relationship to toxic mechanisms

The metabolism and toxicity of 3-methylfuran (3-MF) are described. The major product of metabolic activation of 3-MF appears to be disemicarbazones. Cursory description of toxic effects of 3-MF on lung and kidneys are provided. 18 refs.

Date: January 1, 1983

Creator: Boyd, M. R.; Ravindranath, V.; Burka, L. T.; Dutcher, J. S.; Franklin, R. B.; Statham, C. N. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The bioenergetics of salt tolerance

The aim of this project was to try to understand the adaptive mechanisms that organisms develop in order to respond to a sudden transformation in their environment to a salt shock.'' To study this problem we used a fresh water oxygenic photosynthetic cyanobacterium known as Synecoccus 6311. This organism suffers injury after this sudden exposure to high concentrations of sodium chloride equivalent to or even higher than that in sea water. Yet they are able to re-establish their photosynthetic a… more

Date: January 1, 1991

Creator: Packer, L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Emission computed tomography of /sup 18/F-fluorodeoxyglucose and /sup 13/N-ammonia in stroke and epilepsy

The ECAT Positron Tomograph was used to scan normal control subjects, stroke patients at various times during recovery, and patients with partial epilepsy during EEG monitoring. /sup 18/F-fluorodeoxyglucose (/sup 18/FDG) and /sup 13/N-Ammonia (/sup 13/NH/sub 3/) were used as indicators of abnormalities in local cerebral glucose utilization (LCMR/sub glc/) and relative perfusion, respectively. Hypometabolism, due to deactivation or minimal damage, was demonstrated with the /sup 18/FDG scan in de… more

Date: January 1, 1980

Creator: Kuhl, D. E.; Phelps, M. E. & Engel Jr., J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Physiopathology of blood platelets and development of platelets substitutes. Progress report, August 1, 1976--October 31, 1977. [/sup 51/Cr]

Progress is reported on the following research projects: the effect of estrogen on platelet aggregability and thrombus formation; the antithrombotic effect of platelet inhibiting agents in a bench model of artificial kidney; the arrest of hemorrhage in severely alloimmunized thrombocytopenic patients; and in vivo elution of /sup 51/Cr from labeled platelets induced by antibody. (HLW)

Date: July 31, 1977

Creator: Baldini, M G

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Delayed radiation injury of gut-exposed and gut-shielded mice. II. The decrement in life span

Two mouse strains (RF/J and C57B1/6J) were exposed to x-ray doses totaling 400, 800, and 1200 rad. Total doses were given in 200-rad fractions at 7-day intervals to the whole body, gut only, or bone tissue with the gut shielded. Animals were anesthetized during exposure. Two control groups were used. A sham control group was anesthetized but not exposed to x rays, and another control group received neither anesthesia nor x-radiation. All mice were retained in a standard laboratory environment f… more

Date: January 1, 1978

Creator: Spalding, J.F.; Archuleta, R.F. & Prine, J.R.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Molecular targets, DNA breakage, DNA repair: Their roles in mutation induction in mammalian germ cells

Variability in genetic sensitivity among different germ-cell stages in the mammal to various mutagens could be the result of how much chemical reaches the different stages, what molecular targets may be affected in the different stages and whether or not repair of lesions occurs. Several chemicals have been found to bind very strongly to protamine in late-spermatid and early-spermatozoa stages in the mouse. The chemicals also produce their greatest genetic damage in these same germ-cell stages.… more

Date: January 1, 1989

Creator: Sega, G.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Time series analysis of records of asthmatic attacks in New York City. [Relation to air pollution]

One of several methods developed to search for temporo-spatial patterns in the health variable, as an alternative method to overcome certain shortcomings that afflict the usual techniques of studying the acute health effects of air pollution by multiple regression analyses, were used in an epidemiological study of asthmatic attacks in two areas of New York City (Harlem and Brooklyn), where aerometric monitoring stations are located to provide data on daily fluctuations in air pollution levels. … more

Date: January 1, 1977

Creator: Goldstein, I F & Rausch, L E

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Studies in iodine metabolism. Progress report and publications, 1979-1980

Research programs for the years 1978-1980 is reported. The following subject areas are discussed: (1) iodine 131 monitoring in thyroids of sheep, cattle and humans; (2) radium monitoring in cattle thyroids; (3) the relationship of thyroid function to seizures in rats; (4) the effect of KSCN on thyroglobulin in mice; and (5) studies on excessive iodide intake. (ACR)

Date: January 1, 1980

Creator: Van Middlesworth, L

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Inhalation developmental toxicology studies: Teratology study of n-hexane in rats: Final report

The straight chain hydrocarbon, n-hexane, is a volatile, ubiquitous solvent used in industrial, academic, and smaller commercial environments. The significant opportunity for women of child-bearing age to be exposed to this chemical prompted the undertaking of a study to assess the developmental toxicity of n-hexane in an animal model. Timed-pregnant (30 animals per group) and virgin (10 animals per group) Sprague-Dawley rats were exposed to 0 (filtered air), 200, 1000, and 5000 ppM n-hexane (9… more

Date: December 1, 1987

Creator: Mast, T.J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Proton-induces and x-ray induced fluorescence analysis of scoliotic tissue

Adolescent idiopathic scoliosis is characterized by a curvature or assymetry of the spine which may become progressively more severe, with clinical symptoms appearing just prior to, or during, puberty. The incidence for scoliosis in the age group from 12 to 14 years of age has been reported as high as 8 to 10%, with more than 80% of the cases occurring in females. Although pathologic changes exist in muscles from both sides of the spinal curvature, and no statistically significant side differen… more

Date: February 1, 1980

Creator: Panessa-Warren, B. J.; Kraner, H. W.; Jones, K. W. & Weiss, L. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Predicting effects of cold shock: modeling the decline of a thermal plume

Predicting direct impact of cold shock on aquatic organisms after termination of power plant thermal discharges requires thermal tests that provide quantitative data on the resistance of acclimated species to lower temperatures. Selected examples from the literature on cold shock resistance of freshwater and marine fishes are illustrated to show predictive use. Abrupt cold shock data may be applied to field situations involving either abrupt or gradual temperature declines but yield conservativ… more

Date: October 1, 1977

Creator: Becker, C. D.; Trent, D. S. & Schneider, M. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Congenital malformation and fetal mortality trends in counties surrounding Oak Ridge

Stillbirth and congenital malformation death data have been evaluated for counties surrounding the Oak Ridge nuclear facilities. The observed values were compared with expected values, based on state of Tennessee and East Tennessee rates, for three time periods: prior to the existence of the nuclear facilities; the early years of operation; and the later years of operation. Oak Ridge, which is the closest city to the nuclear facilities, had significantly fewer stillbirths and no difference in c… more

Date: December 1, 1979

Creator: Shank, K. E.; Easterly, C. D. & Oakes, T. W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Damage and repair of irradiated mammalian brain

We have demonstrated that focal charged particle irradiation of the rabbit brain can create well-defined lesions which are observable by nuclear magnetic resonance imaging (NMR) and positron emission tomography (PET) imaging techniques. These are similar, in terms of location and characteristic NMR and PET features, to those that occur in the brain of about 10% of clinical research human subjects, who have been treated for intracranial vascular malformations with stereotactic radiosurgery. Thes… more

Date: July 1, 1989

Creator: Frankel, K.; Lo, E.; Phillips, M.; Fabrikant, J.; Brennan, K.; Valk, P. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Comparison of remotely acquired deep-body and subdermal temperature measurements for detecting fever in cattle

Results of two studies in which deep-body and subdermal temperatures were compared with fevers that were experimentally induced with viruses are given. In the first study, test animals were held indoors where ambient temperatures were stable; in the second study, animals were held outdoors during the winter months when temperatures were highly variable. A computerized temperature telemetry system used for the studies is described for the first time. (PSB)

Date: January 1, 1983

Creator: Seawright, G. L.; Brown, R. R.; Campbell, K.; Levings, R. L. & Araki, C. T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

New methodlogy for measuring damage to respiratory tract cells using flow-system cell-analysis techniques

Automated flow-system cell-analysis techniques provide a new method for determining damage to respiratory tract cells in humans exposed by inhalation of environmental pollutants such as from the production of synthetic fuels from coal and oil shale. This paper describes results of preliminary experiments designed to develop flow-system instrumentation methods for measuring biological damage to respiratory tract cells using the Syrian hamster as a model. Hamster respiratory tract cell samples we… more

Date: January 1, 1977

Creator: Steinkamp, J. A.; Hansen, K. M.; Wilson, J. S. & Salzman, G. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Design and analysis of aquatic monitoring programs at nuclear power plants.

This report addresses some of the problems of designing, conducting, and analyzing aquatic environmental monitoring programs for impact assessment of nuclear power plants. The concepts discussed are applicable to monitoring the effects of chemical, radioactive, or thermal effluents. The concept of control and treatment station pairs is the fundamental basis for the experimental method proposed. This concept is based on the hypothesis that the relationship between the two stations forming the pa… more

Date: November 1, 1977

Creator: McKenzie, D. H.; Kannberg, L. D.; Gore, K. L.; Arnold, E. M. & Watson, D. G.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Generation of dose-response relationships to assess the effects of acidity in precipitation on growth and productivity of vegetation

Experiments were performed with several plant species in natural environments as well in a greenhouse and/or tissue culture facilities to establish dose-response functions of plant responses to simulated acidic rain in order to determine environmental risk assessments to ambient levels of acidic rain. Response functions of foliar injury, biomass of leaves and seed of soybean and pinto beans, root yields of radishes and garden beets, and reproduction of bracken fern are considered. The dose-resp… more

Date: January 1, 1981

Creator: Evans, L.S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Dosimetry of inhaled plutonium-239 dioxide in rodent lung: a morphometric study

Morphometric analysis of rat and hamster lung did not demonstrate any extensive changes in lung composition or structure following inhalation exposure to /sup 239/Pu0/sub 2/ at levels near that for maximum tumor yield in rats. The problem of dosimetry for this compound thus appears to be relatively uncomplicated by any major radiation-induced pathological alterations in the lung. Rat and hamster lung were found to be similar in structure and composition, with few significant differences which c… more

Date: June 1, 1979

Creator: Rhoads, K.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Reassessment of data used in setting exposure limits for hot particles

A critical review and a reassessment of data reviewed in NCRP Report 106 on effects of hot particles'' on the skin of pigs, monkeys, and humans were made. Our analysis of the data of Forbes and Mikhail on effects from activated UC{sub 2} particles, ranging in diameter from 144 {mu}m to 328 {mu}m, led to the formulation of a new model for prediction of both the threshold for acute ulceration and for ulcer diameter. A dose of 27 Gy at a depth of 1.33 mm in tissue in this model will result in an a… more

Date: May 1, 1991

Creator: Baum, J.W. & Kaurin, D.G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Biological effects of 60-Hz electric fields on small and large laboratory animals

Rats and mice were exposed to 60-Hz electric fields up to 330 kV/m for durations as long as four months. No significant effects were found in the following major areas: metabolic status and growth; organ and tissue morphology; brain morphology; cardiovascular function; serum chemistry; reproduction; prenatal growth and development; teratology; bone growth; peripheral nerve function; humoral and cell-mediated immunity; susceptibility to viral infection; cell and membrane function; illness/malais… more

Date: January 1, 1981

Creator: Phillips, R.D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Quarterly Progress Report Covering Period October 1 Through December 31, 1978 Biocide By-Products in Aquatic Environments

Analysis of water samples from several locations across the U.S. is underway. We have completed analysis using the Purge and Trap and headspace techniques on several locations. In the freshwater phase of the program we have completed fifteen chloroform acute toxicity bioassays with rainbow trout (Salmo gairdneri), bluegill (Lepomis macrochirus), and catfish (Ictalurus punctatus). Results indicate, in all cases, the LC-50 is well above that which could be expected to be discharged due to power p… more

Date: March 1, 1979

Creator: Anderson, D.R.; Bean, R.M. & Gibson, C.I.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Comparative vs ontogenetic paradigms for tests of the intrinsic mutagenesis hypothesis of aging

This paper examines certain aspects of the biology of longevity and aging that bear on the role of DNA in the ontogenetic aging process, and on the genetic basis for the differences of longevity among mammal species. (PCS)

Date: January 1, 1979

Creator: Sacher, G.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Health aspects of power transmission. [Effects of 60 Hz electric field on biochemical, morphological, and physiological parameters in mice and rats]

Exposure of rats and mice to 60-Hz electric fields at 100 kV/m for up to 120 days had no statistically significant, reproducible effects on a number of measures of metabolic status and growth, bone growth and structure, reproduction, hematology and serum chemistry, endocrinology, cardiovascular function, nerve function, or organ and tissue morphology. An effect on cell-mediated immunity was detected and is being evaluated further in additional experiments. Exposure of rats in utero (day 0 of ge… more

Date: March 1, 1979

Creator: Phillips, R. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department