4 Matching Results

Search Results

Advanced search parameters have been applied.

Thyroid ultrastructural changes induced by hypothermia

Description: Investigations have shown that the hypothalamus and pituitary respond to decreases in body temperature by stimulating the thyroid gland to release T3 and T4 hormones. This study was designed to investigate ultrastructural changes of the thyroid gland induced by hypothermia. The ultrastructural changes produces by stimulation by Thyroid Stimulating Hormone were also examined as an adjunct to the hypothermic stimulation of the gland.
Date: August 1979
Creator: Kent, James Simpson
Partner: UNT Libraries

Study on the induction of thyroid tumors in rats using x irradiation in conjunction with a goitrogen. [1 methyl--2 mercaptoimidazole (methimazole)]

Description: The influence of acute localized thyroid x irradiation and chronic goitrogen administration, separately or combined, on thyroid tumor formation in mature female rats was studied. In the first experiment, the radiation doses were 0, 80, 160, 320, or 640 rads, and the dosages of goitrogen were 0, 4, or 40 parts per million (ppM) of 1 methyl - 2 mercaptoimidazole (MMI). The incidence of rats with thyroid tumors in any treated group receiving 0 or 4 ppM MMI was not significantly greater than the incidence in the nontreated control group. However, the incidence in any of the 40 ppM MMI groups was significantly greater than that in the nontreated control group. At all the radiation doses other than 80 rads, the incidence was significantly greater than that in the non-irradiated group. No significant difference was seen in the incidence of rats with thyroid tumors on the basis of radiation dose. The incidence was so high at 80 rads that there was little margin for further increase by increasing the radiation dose. The mean serum thyroxine levels at 40 ppM MMI, 4 ppM MMI, and 0 ppM MMI were 1.9, 3.5, and 3.7 ..mu..g/100 ml, respectively. No markedeffect of thyroid irradiation on mean serum thyroxine levels was seen. In the second experiment, rats receiving 200 ppM MMI and thyroid irradiation were sacrificed at 7-1/2 months after treatment. Nearly all rats in the 0 and 80 rad groups and all in the 160, the 320, and the 640 rad groups had thyroid tumors. In the third experiment, serum T/sub 4/ levels were measured in treated rats. Rats receiving 640 rads + 0 ppM MMI showed a slight decrease in serum T/sub 4/, while no change in serum T/sub 4/ levels was seen in rats receiving 0 rads + 4 ppM MMI or ...
Date: January 1, 1979
Creator: Mahler, P.
Partner: UNT Libraries Government Documents Department

Environmental monitoring at Argonne National Laboratory. Annual report for 1978

Description: The results of the environmental monitoring program at Argonne National Laboratory for 1978 are presented and discussed. To evaluate the effect of Argonne operations on the environment, measurements were made for a variety of radionuclides in air, surface water, Argonne effluent water, soil, grass, bottom sediment, and foodstuffs; for a variety of chemical constituents in air, surface water, and Argonne effluent water; and of the environmental penetrating radiation dose. Sample collections and measurements were made at the site boundary and off the Argonne site for comparison purposes. Some on-site measurements wee made to aid in the interpretation of the boundary and off-site data. The results of the program are interpreted in terms of the sources and origin of the radioactive and chemical substances (natural, fallout, Argonne, and other) and are compared with applicable environmental quality standards. The potential radiation dose to off-site population groups is also estimated.
Date: March 1, 1979
Creator: Golchert, N W; Duffy, T L & Sedlet, J
Partner: UNT Libraries Government Documents Department

AQUAMAN: a computer code for calculating dose commitment to man from aqueous releases of radionuclides. [Internal and external dose conversion factors and bioaccumulation factors for 56 radionuclides]

Description: AQUAMAN is an interactive computer code for calculating values of dose (50-year dose commitment) to man from aqueous releases of radionuclides from nuclear facilities. The data base contains values of internal and external dose conversion factors, and bioaccumulation (freshwater and marine) factors for 56 radionuclides. A maximum of 20 radionuclides may be selected for any one calculation. Dose and cumulative exposure index (CUEX) values are calculated for total body, GI tract, bone, thyroid, lungs, liver, kidneys, testes, and ovaries for each of three exposure pathways: water ingestion, fish ingestion, and submersion. The user is provided the option at the time of execution to change the default values of most of the variables, with the exception of the dose conversion factor values. AQUAMAN is written in FORTRAN for the PDP-10 computer.
Date: February 1, 1979
Creator: Shaeffer, D. L. & Etnier, E. L.
Partner: UNT Libraries Government Documents Department