Walter E. Kisieleski

The Correlation of Autoradiographic Grain Counts and Tritium Concentration in Tissue Sections Containing Tritiated Thymidine

The correlation between the number of developed silver grains in an autoradiographic emulsion and the concentration of tritium atoms in the underlying cells was studied in tissue sections labeled in vivo with tritiated thymidine. The results indicate that, in a tissue section 3 mu thick, from 100 to 200 disintegrations of tritium atoms are required to render developable 1 silver grain in the emulsion overlying the labeled locus. (auth)

TUMOR INDUCTION IN MICE BY RADIOACTIVE THYMIDINE

thymidine in mice and to investigate the possibility of inducing tumors with tritiated thymidine. Although it appeared likely on theoretical grounds that tritiated thymidine could be carcinogenic under appropriate experimental conditions, there were no reports to that effect in the literature at that time, and none have appeared since then with the exception of our own earlier communications. Thymidine, as a precursor of DNA, is incorporated almost exclusively into the nucleus of cells synthesizing DNA prior to mitosis (3). About 10 % of the injected thymidine is incorporated into new DNA of proliferating cells (4), while the remainder is promptly catabolized to tritiated water and other nonvolatile compounds (5). The biological half-life of tritiated water in mice is from 24 to 36 hours (6, 7), while the thymidine incorporated into DNA remains there until the death of the cell or its descendants. The 3-particles from tritium incorporated into DNA from H3-thymidine produce an irradiation which primarily affects the cell nucleus, since about 90% of the energy (0.01795 Mev) of these particles is dissipated within the 1 This work was supported in part by contract AT(11-1)-1131 from the U. S. Atomic Energy Commission, and in part performed under the auspices of this commission.

Cleft palate induction. Quantitative studies of 3h corticoids in a/jax mouse tissues after maternal injections of 3h cortisol.

A/Jax mice were injected with 50 μCi of 3 H cortisol and 10 mg of cortisone acetate on day 12 of gestation. At various intervals after injection, the maternal liver, placenta, yolk sac, and the fetal jaws were removed and analyzed by thin-layer chromatography in conjunction with oxidative combustion and liquid scintillation counting to identify and measure the amount of labeled corticoid metabolites. The results support the thesis that these corticoids may induce clefts by an individual or combined direct action on the fetal jaws and palatal shelf tissue.

Microscopic tracing of deuterium.

The development of the ion microprobe analyser has made it possible to follow stable isotopes with microscopic resolution in biological and other materials. An ion microprobe using an oxygen primary beam has been found to produce relatively few mass 2 ions (+ or ‐) on organic samples. This technique should permit the use of deuterium as a practical tracer with a resolution of about 1μm in the plane of the section and 2 nm in the depth dimension with available instruments.

Increased Incidence of Tumor Metastases in Female Mice

Most of the tumor cells injected into the tail vein of mice fail to survive at the site of arrest in the lungs, but the percentage of surviving cells is higher in females than in males. The surviving cells, however, grow at a similar and constant rate in both sexes.

Application of liquid scintillation counting method in irradiation studies of coal

Abstract Coal was irradiated with ionizing radiation in neutral, basic and acidic solutions of ethanol-1-14C. The reacted coal was then oxidized and the collected 14CO2 measured in a liquid scintillation counter. Good reproducibility and efficient and quantitative recovery of 14CO2 was observed. The method should find wide application in studies to understand mechanisms of free-radical reactions with coal as well as with organic compounds.

The Effect of BAL on Distribution and Metabolism of P32 and Sr90

Summary The effectiveness of 2,3-dimer-captopropanol (British anti-lewisite) in increasing the elimination of injected P32 and Sr90 in mice was investigated. It is concluded that BAL is essentially without effect although, in the case of P32, the rate of uptake in bone appears to be reduced during the first hour. No such differences could be demonstrated after 24 hours.

THE USE OF LIQUID SCINTILLATION COUNTING IN THE STUDIES OF COAL AND COAL DERIVED LIQUIDS

Coal and coal derived liquids were treated with radio labeled ( 14 C or 3 H) acetic acid, ethanol, methanol and water. Coal derived liquids were allowed to react with 1- 14 C-acetic anhydride in pyridine to form acetate derivatives of phenols, alcohols, primary and secondary amines. The samples were then oxidized and collected 14CO 2 or 3 H 2 O measured in a liquid scintillation counter. Good reproducibility and quantitative recovery of 14 CO 2 and 3 H 2 O were observed. The liquid scintillation counting method was very useful for quantitation of hydroxyl groups and primary and secondary amines in coal derived liquids. The amount of adsorption of acetic acid, ethanol, methanol, and water was also measured. They found it to be irreversibly adsorbed on coal. Other techniques, such as 1 H and 13 C nmr as well as titration of liberated acetic acid, are inefficient in quantitative determination of acid groups in coal. Only tracer methodology was able to determine adsorption of solvent on coal efficiently.

SAMPLE OXIDATION FOR LIQUID SCINTILLATION COUNTING: A REVIEW

The liquid scintillation spectrometer is a versatile instrument for the measurement and analysis of low-energy beta emitters, especially hydrogen-3 (tritium) and carbon-14. On the other hand, biological materials as well as environmental samples are most difficult to prepare as true solutions for liquid scintillation counting and present unique problems in sample preparation. To overcome problems of sample solubility, quenching, and chemiluminescence, a more universal preparation technique can be achieved if the sample is burned at red heat in an atmosphere of oxygen and the carbon and hydrogen converted into carbon dioxide and water and quantitatively dissolved in a scintillator to produce an unquenched sample. A number of methods of oxidizing samples for liquid scintillation counting are discussed. Experimental studies using carbon-14 and tritium are presented and potential application to biological and environmental problems are considered.