Preparation of tritium-labeled compounds. II. Chlorphenesin carbamate by exposure to tritium gas and determination of intramolecular distribution of tritium.
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Animals↗
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Preparation of tritium-labeled compounds. 3. Lincomycin by exposure to tritium gas and partial determination of intramolecular distribution of tritium.
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Chromatography↗
Comparative biokinetics of tritium in rats during continuous ingestion of tritiated water and tritium-labeled food.
PURPOSE: The biokinetics of tritium during continuous ingestion of tritiated water and tritiated wheat were investigated to estimate the radiation dose rates at the end of two modes of chronic exposure. MATERIALS AND METHODS: Wistar strain male rats continuously ingested tritiated water as drinking water and tritiated wheat as food for 14 weeks. Urine and tissue samples were obtained and total tritium in the fresh wet samples and organically bound tritium (OBT) in the freeze-dried samples were determined. RESULTS: The biokinetics of tritium was different between the two modes of exposure. The concentration of total tritium in the tissues exposed to tritiated water attained a steady-state condition by 2-3 weeks. The steady-state condition in the case of exposure to tritiated wheat was not observed for 10 weeks after the start of exposure in the majority of tissues. The relatively efficient and prolonged OBT formation during chronic exposure to tritiated wheat resulted in relatively high incorporation and retention of tritium in the tissues compared with those for exposure to the same activity of tritiated water. CONCLUSION: Radiation dose rates estimated at the end of continuous ingestion showed that tritiated wheat gave higher dose rates than tritiated water by a factor of 1.3 to 4.5, but the factors were within 2.0 in the majority of tissues except for small intestine and adipose tissue.
Administration, Oral↗
[Incorporation of tritium into the DNA of hematopoietic tissues during prolonged administration of tritium oxide].
With long-term (90 days) administration of tritium oxide (0.37 MBq/g body weight) to ras the carbon-bound tritium accumulated in DNA of haemopoietic tissues during two-month administration of the isotope (the accumulation half-time of 15-25 days); during the next month, the isotope level remained nearly constant (about 20 X 10(6) decay/min/g DNA). Elimination of tritium from DNA started 3 days after termination of its administration and proceeded with two half-times (4-8 days and 12-18 days). The ratio of the tritium content per 1 M hydrogen of DNA to tritium content per 1 M hydrogen of tissue water increased up to 0.5-0.7 during the uptake of tritium oxide, and up to 4-7 after the administration of the isotope had ceased.
Animals↗
Influence of the tritium beta(-) decay on low-temperature thermonuclear burn-up in deuterium-tritium mixtures
Low-temperature (T</=15 keV) thermonuclear burn-up in deuterium-tritium mixtures with various deuterium-tritium-helium-3 ratios is considered. The general dependence is studied for the critical burn-up parameter x(c)=rhor(c) upon the initial temperature T, density rho(0), and tritium molar concentration y for the [D]:y[T]:(1-y)[3He] mixture. In particular, it is shown that, if the tritium concentration y decreases, then the critical burn-up parameter x(c)(T,rho(0),y) grows very quickly (at fixed T and rho(0)). This means that tritium beta(-) decay significantly complicates thermonuclear burn-up in deuterium-tritium mixtures.
Journal Article↗
[Efficiency of tritium enrichment by electrolytic cell with multi-nickel-plates electrode and its application to the determination of tritium in environmental water].
For the purpose of speeding up the tritium enrichment by electrolysis, we have produced an electrolytic cell with the multi-plate-electrode system instead of the commonly used single-plate-electrode, and examined the efficiencies for the tritium enrichment under the conditions of different current densities and electrode gaps. From the results, the tritium recovery and the separation factor beta were found to be maximized under the condition of 70 mA/cm2 of current density and 1.6 mm of electrode gap, and they were 90 percent and 23, respectively. Using this cell, it took 28 hours to reduce 100 ml of a sample water to 10 ml, and took 2 days, including the time required for other operations, to determine the tritium concentration of 1.85 Bq/l (50 pCi/l) with the counting error of within +/- 10 percent. This method has been applied to determining the tritium concentrations of environmental samples from Yamato River region during July 1981-February 1983. They were in the range of 1.11-9.48 Bq/l (30-256 pCi/l).
Electrodes↗
Calculation of radiation-induced DNA damage from photons and tritium beta-particles. Part II: Tritium RBE and damage complexity.
Yields of DNA single- and double-strand breaks (SSB and DSB) in nucleosomal DNA were calculated for 137Cs, 70 keV photons and tritium beta-particles by Monte Carlo means. Monte Carlo-generated electron tracks for liquid water were used to model energy deposition. Chemical evolution of a track and interactions between species and DNA following water radiolysis were modelled in an encounter-controlled manner. The calculated relative biological effectiveness (RBE) for DSB production for tritium against 137Cs was 1.2 for the total DSB yield. Tritium beta-particles were slightly more efficient compared to 137Cs in producing complex DSB, defined as DSB accompanied by additional strand breaks. The RBE for complex DSB formation was 1.3. Most complex DSB exhibited associated base damage; the extent of the base damage was similar for all the radiation types considered. Correlated DSB conforming to nucleosome periodicity were observed. However, their frequency was low, of the order of 2% of total DSB. For all the DNA damage endpoints considered and their response to variation of the scavenging environment or DNA conformation no difference was observed between 70 keV photons and tritium beta-particles.
Beta Particles↗
Blood tritium level as a conservative estimate of soft tissue dose after tritium injection in mice.
The usefulness of the determination of the tritium concentration in blood for estimating the average soft tissue dose after tritium intake was tested. Tritiated water and a mixture of tritiated amino acids dissolved in saline solution were separately administered to adult male mice by intraperitoneal injection. The tritium levels in the blood, urine, whole body, spleen, liver, testis, and brain were then determined at various periods. With both types of tritium administration, the results suggested that the accumulated dose in the blood pool gave a conservative estimate of the accumulated dose to the soft tissue.
Amino Acids↗
Synthesis of tritium- and deuterium-labeled 9-beta-D-arabinofuranosyladenine and the tritium-labeled 5'-monophosphate ester with increased metabolic stability.
Preparation of both a 5'-deuterium and a 5'-tritium-labeled 9-beta-D-arabinofuranosyladenine (6a and 6b) by reduction of the protected 5'-aldehyde 4 is described. Conversion of 6b to the 5'-tritium-labeled 5'-monophosphate 7b was effected directly with a phosphoryl chloride-formic acid reagent. The product 7b exhibited consistently higher blood levels of nonvolatile tritium than the 2-labeled compound when tested in dogs.
Adenine Nucleotides↗
Tritium excretion after intravenous administration of tritium labelled adrenaline and noradrenaline and digital vascular reactivity to adrenaline and noradrenaline in normotensive and labile hypertensive subjects.
1. The 24-h urinary excretion of tritium after tritiated adrenaline administration and digital vascular reactivity to exogenously administered adrenaline and noradrenaline were measured in ten normotensive and in twenty-eight labile essential hypertensive subjects. Tritiated noradrenaline excretion and apparent noradrenaline secretion rate were also measured in ten and eleven of these subjects, respectively. 2. Despite overlapping, the mean 24-h tritium excretion after 3H-adrenaline administration as well as reactivity to adrenaline were significantly greater in the hypertensive than in the normotensive subjects, whether or not they had increased responsiveness to noradrenaline. Significant correlation, however, was observed between tritium excretion of adrenaline and reactivity to adrenaline in both labile hypertensive and normotensive subjects. These measurements were also both significantly correlated with percentage variability in systolic and diastolic blood pressure in the labile hypertensive subjects. 3. No significant correlation was observed between adrenaline as against noradrenaline measurements, whether physiological or biochemical, in either hypertensive or normotensive subjects.
Blood Pressure↗
Investigation of tritium incorporation of tritium incorporation by means of excreted metabolites.
The commonly accepted urine analysis by liquid scintillation method was applied for whole body dose estimating. After the separation of metabolite fractions the organically bound tritium in urine could be measured. Urine samples from workers repeatedly exposed to tritium incorporation during the chemical processing of various labeled compounds have been collected and analyzed. The time dependence of tritium activity in certain metabolites was found to be characteristic, significantly differing from the 3H concentration curve of the native or treated urine sample.
Creatinine↗
The incorporation of tritium from tritium-enriched water into UDP-N-acetylglucosamine and UDP-N-acetylmannosamine catalyzed by UDP-N-adetylglucosamine 2-epimerase from Escherichia coli.
Uridine diphosphate N-acetylglucosamine 2-epimerase from Escherichia coli 014 K7 H- catalyzes the reversible epimerization of uridine diphosphate N-acetylglucosamine to uridine diphosphate N-acetylmannosamine. During epimerization, tritium from tritium-enriched water is incorporated into both uridine diphosphate N-acetylglucosamine and uridine diphosphate N-acetylmannosamine. The position of incorporation is C-2 of the N-acetylhexosamine moieties.
Carbohydrate Epimerases↗
Metabolism in normal and virus-transformed chick embryo fibroblasts as observed with glucose labeled with 14C and tritium and with tritium-labeled water.
Glucose metabolism in normal and virus-transformed chick embryo fibroblast cells in culture was observed by allowing the cells to metabolize [U-14C]glucose plus glucose labeled with tritium in the C-1, C-3, and C-6 positions. Similarities and differences between normal and transformed cells were observed and measured. Both normal and transformed cells are found to metabolize about 20% of the glucose via the oxidative pentose phosphate cycle, with the rates being about twice as much for transformed cells as for normal cells under the chosen conditions. Nevertheless, the ratio of glucose metabolized via oxidative pentose cycle to the net flow of that metabolized directly to fructose 6-phosphate is about the same in normal and transformed cells. Although the rate of flow of [14C]glucose into the tricarboxylic acid cycle intermediates and amino acids derived from them appears to be the same in normal and transformed cells, the rate of tritium incorporation from H3HO into these intermediates seems to be much higher in normal cells.
Animals↗
Biokinetics of tritium incorporation into the tissues of rats during continuous ingestion of tritiated water or tritium-labeled food.
Wistar strain male rats were continuously given tritiated water or tritiated wheat as drinking water or food for 70 days. During the ingestion, the tritium incorporation into rat tissues was examined in both wet and dry samples of liver, kidney, testis and blood. The concentration of organically bound tritium (OBT) in dry tissues of rats exposed to tritiated water (HTO) and 3H-food (tritiated wheat) attained an equilibrium within 2-3 weeks after the exposure. The concentration of OBT in dry tissues of rats exposed to HTO also reached an equilibrium within 3-4 weeks after the exposure. However, rats exposed to 3H-food, except for the liver, such an equilibrium state was not reached in other tissues and the OBT concentrations increased gradually throughout the exposure. The relative concentrations of total 3H and OBT at the end of the chronic ingestion of 3H food (70 day), expressed in percentages of the total activity were 1 and 9 times higher than those in rats exposed to HTO, respectively. In both groups, OBT as well as total 3H was almost uniformly distributed among the tissues examined.
Animals↗
[Tritium labeling of tRNA by the tritium thermal activation method].
Tritium labelled E. coli total tRNA and tRNAPhe are prepared by action of thermally activated tritium atoms. The preparations, having the molar radioactivity up to 3.6 Ci/mmol, are useful for functional investigations.
Activation Analysis↗
New development in the tritium labelling of peptides and proteins using solid catalytic isotopic exchange with spillover-tritium.
The mechanism of the reaction of high temperature solid state catalytic isotope exchange (HSCIE) of hydrogen in peptides with spillover-tritium at 140-180 degrees C was analyzed. This reaction was used for preparing [(3)H]enkephalins such as [(3)H]DALG with specific activity of 138 Ci/mmol and [(3)H]LENK with specific activity of 120 Ci/mmol at 180 degrees C. The analogues of [(3)H]ACTG(4-10) with specific activity of 80 Ci/mmol, [(3)H]zervamicin IIB with specific activity of 70 Ci/mmol and [(3)H]conotoxin G1 with specific activity 35 Ci/mmol were produced. The obtained preparations completely retained their biological activity. [(3)H]Peptide analysis using (3)H NMR spectroscopy on a Varian UNITY-600 spectrometer at 640 MHz was carried out. The reaction ability of amino fragments in HSCIE was shown to depend both of their structures and on the availability and the mobility of the peptide chain. The reaction of HSCIE with the beta-galactosidase from Termoanaerobacter ethanolicus was studied. The selected HSCIE conditions allow to prepare [(3)H] beta-galactosidase with specific activity of 1440 Ci/mmol and completely retained its the enzymatic activity.
Amino Acid Sequence↗
A simple fast micromethod for measuring enzyme activities which release tritium as tritium water.
The entire procedure is carried out in a counting vial by mixing the reagents as a 20- to 30-microliters drop in the cap of a counting vial, incubating, quenching the reaction, and then distilling the tritium water produced into the chilled vial, in which it is assayed after the addition of scintillation solvent and a clean cap. The application of this technique to the analysis of serum transaminases is described.
Humans↗
[Mutagenic action of tritium on the germ cells of male mice. II. The genetic damages in stem spermatogonia induced by tritium oxide and gamma radiation].
The frequency of reciprocal translocations (RT) induced by single injection of tritiated water (THO) (3.3; 6.3 and 12.6 MBq/g) or by referent 137Cs gamma irradiation was studied. The absorbed doses in testis were: 1; 2 and 4 Gr. The frequency of RT per 100 cells were 0.4; 1.1 and 2.5 after THO administration, and 0,5; 0.9 and 1.2 after single exposure to gamma irradiation, respectively. The RBE of tritium increased from 1 at the dose of 1 Gr to 2, at the dose of 4 Gr.
Animals↗