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PubMed1987

[Characteristics of incorporation of carbohydrate radioactivity into structural proteins of the tick-borne encephalitis virus].

The propagation of the tick-borne encephalitis virus in the culture of the porcine embryo kidney cells containing the radioactive mannose and glucosamine results in incorporation of radioactive label into hemagglutinin V3(E) as well as into other structural proteins, the nucleocapsid protein V2(C) and membrane protein V1(M). The possible reasons for carbohydrates borne radioactivity incorporation into the proteins V2 and V1 are discussed.

Carbohydrates↗
PubMed1986

Biliary excretion and organ distribution of 14C radioactivity after 14C-2-ethylhexyl acrylate administration in rats.

Rats were intravenously administered (14C)-2-ethylhexyl acrylate at the dose 10 mg/kg or 50 mg/kg b. w. Biliary excretion of 14C-radioactivity was followed in 1-3 hour intervals within the first 24 hours after administration. The rats were then sacrificed and distribution of 14C-radioactivity was followed in some organs. Highest radioactivity was found in liver, less in the kidneys and the least in the brain. A significant increase of bile flow was observed. In the 24-hour intervals 2.2% of the dose was eliminated via bile at both dosages, most of it (83%) during the first 3 hours.

Acrylates↗
PubMed1979

Hyperthyroidism due to functioning metastatic thyroid carcinoma. Precipitation of thyroid storm with therapeutic radioactive iodine.

Two patients had hyperthyroidism secondary to functioning metastatic follicular thyroid carcinoma. Failure to control the thyrotoxic state with antithyroid drugs in one patient prior to treatment with radioactive iodine led to exacerbation of the thyrotoxicosis with thyroid storm and death. A second patient, in whom a euthyroid state was induced before radioactive iodine therapy, had a benign posttreatment course. Radioactive iodine therapy of functioning metastatic thyroid carcinoma should be administered with caution and only after adequate preparation of the elderly patient with cardiovascular disease.

Acute Disease↗
PubMed1972

Pancreas acinar cell differentiation. VII. Autoradiographic demonstration of intracellular radioactivity with with S-adenosyl-L-(C 3 H 3 ) methionine.

After rat pancreas anlagen were grown in an organ culture medium for 9 days and further incubated for 15, 30 or 60 minutes in media to which C(3)H(3)-Sadenosyl-L-methionine (C(3)H(3)-SAM) was added, autoradiography demonstrated radioactivity in the nucleolus, nucleus and cytoplasm of the acinar cell. Under similar circumstances, except that the anlagen were grown in a methionine-deficient (CD-MD) medium prior to incubation with C(3)H(3)-SAM, much greater concentrations of radioactivity were present in the nucleolus, nucleus and cytoplasm of the acinar cell than in the respective compartments of anlagen grown in control medium. The nucleolus showed the highest concentration of radioactivity in anlagen grown in either control or methionine-deficient medium. The nucleolus of the acinar cell of anlagen grown in CD-MD medium appeared to be the most undermethylated cellular compartment and was larger than the nucleolus of the acinar cell grown in the control CD medium, so it is possible that a deficient methylation of ribosomal RNA precursors led to a piling up of RNA in the nucleolus and a decrease in the flow of ribosomal precursors to the cytoplasm. Other substance might have been undermethylated and thereby have inhibited differentiation.

Animals↗
PubMedDate not supplied

Binding of radioactivity from (14C)thiourea to rat lung protein.

Binding of radioactivity from [14C]thiourea (TU) to rat lung protein was found to occur in vitro. Two binding sites are present. One possesses low affinity/high capacity while the other is characterized by high affinity/low capacity. In vitro binding of [14C]TU to lung protein can be antagonized by the presence of either unlabeled congeners (alpha-napthylthiourea or phenylthiourea) or thiol-containing compounds (cysteine, reduced glutathione). Conversely, depletion of lung-reduced glutathione by means of diethyl maleate administration results in elevated protein binding. Prior administration (24 hr) of a sublethal dose of TU (which renders tolerance to a subsequent lethal dose in vivo) results in a decrease in in vitro binding of radioactivity from [14C)TU to lung protein. In addition, immature rats, which are less sensitive to the edematogenic effect of TU, bind less radioactivity from [14C]TU to lung protein when the drug is administered in vivo. These results suggest a correlation between [14C]TU binding to lung protein and the pathophysiological effect of the drug in the lung.

Aging↗
PubMed1967

Distribution of radioactive glycerol and fatty acids among adipose tissue triglycerides after administration of glucose-U-14C.

Adipose lipid obtained from fed rats 15 or 60 min after injection of radioactive glucose was separated into 10 triglyceride classes of differing fatty acid compositions. The distribution among these classes of total and radioactive triglyceride-glycerol was determined and found to be the same. Thus newly synthesized adipose triglycerides resemble in kind and proportion the triglycerides which exist in the tissue. This finding is in accord with the concept that the structures of adipose triglycerides are stable over long periods and that the turnover rate of the several triglyceride species are similar. After administration of radioactive glucose, the specific activity of saturated fatty acids was higher in the more saturated triglyceride species. These data indicate that newly formed saturated acids do not mix completely with all adipose tissue fatty acids available for esterification. Fatty acids derived from plasma triglyceride influenced the composition of newly synthesized adipose tissue triglyceride and thus constitute an important source of adipose tissue lipid.

Adipose Tissue↗
PubMed1984

[Continuous measurement of lysis of radioactively marked fibrin clots].

Methods for continuous measurement of dissolution of experimentally induced radioactively labelled thrombi were described. They are suited for the use in artificial circulating systems and in animal experiments. The radioactivity can be measured continuously in a circulating system by fitting a flow through cell with a well scintillator. In order to measure thrombotic processes in vivo, we developed a specially adapted single hole collimator. By this device changes in radioactivity over a defined occluded area of the vessel could be detected. The usefulness of the methods was demonstrated by means of a thrombolytic agent.

Animals↗
PubMed1984

[Effects of pretreatment with isoprenaline and conditions of perfusion on the specific radioactivity of ATP in rat heart].

14C adenine was supplied to isolated Rat heart retrograde perfused. The experiment was continued by aortic or atrial perfusion and the evolution of the specific radioactivity of ATP was estimated. Aortic perfusion did not reduce ATP content and the specific radioactivity decreased, expressing the turnover of adenine nucleotides. On the contrary, working heart perfusion provoked a breakdown of ATP and an increase of ATP specific radioactivity. When myocardial ATP was decreased prior to the perfusion with isoproterenol, the incorporation of 14C adenine was enhanced, a further aortic perfusion induced a greater decrease of ATP specific activity than in controls. Atrial perfusion did not change the concentration and the specific activity of ATP. These data seem to provide experimental evidences for a compartmentalization of myocardial ATP.

Adenosine Triphosphate↗
PubMed1983

Radioactivity incorporation into different cerebral phospholipids after oral administration of 14C methyl CDP-choline.

Oral administration of 14C methyl CDP-choline in Sprague-Dawley rats provided the following data: --Radioactivity from cytidine diphosphate choline (CDP-choline, citicoline, Somazina) is found in the brain at a high rate. --62.8% of total radioactivity measured in the brain is found as a part of phospholipids. --This radioactivity is detected by the labelling of phosphatidyl-choline and endogenous sphingomyelin from CDP-choline. This suggests that CDP-choline by oral administration has effects on the synthesis of basic phospholipids being essential for the structure and function of the cellular membrane.

Administration, Oral↗
PubMed1983

Distribution and clearance from the body of an oxypolygelatin plasma substitute determined by radioactive tracer study in chimpanzees.

The organ distribution of a colloidal plasma substitute on the basis of oxypolygelatin (Gelifundol S) has been determined in chimpanzees with radioactively tagged material. The radioactivity was distributed uniformly in the whole body and after 24 h it was nearly completely excreted. As liver, spleen, heart, lungs and kidneys were not depicted radiographically in contrast to the body background, it can be concluded that ther e is no preference for the colloid to be stored in any of these organs. Only in the bladder a transiently higher radioactivity could be measured. The urine was collected fo 7 d and contained 91.5% of the colloid originally infused.

Animals↗
PubMed1984

Radioactive iodine therapy in cats with hyperthyroidism.

Eleven cats with hyperthyroidism were treated with radioactive iodine (131I). Previous unsuccessful treatments for hyperthyroidism included hemithyroidectomy (2 cats) and an antithyroid drug (7 cats). Two cats had no prior treatment. Thyroid scans, using technetium 99m, showed enlargement and increased radionuclide accumulation in 1 thyroid lobe in 5 cats and in both lobes in 6 cats. Serum thyroxine concentrations were high and ranged from 4.7 to 18 micrograms/dl. Radioactive iodine tracer studies were used to determine peak radioactive iodine uptake (RAIU) and effective and biological half-lives. Activity of 131I administered was calculated from peak RAIU, effective half-life, and estimated thyroid gland weight. Activity of 131I administered ranged from 1.0 to 5.9 mCi. The treatment goal was to deliver 20,000 rad to hyperactive thyroid tissue. However, retrospective calculations based on peak RAIU and effective half-life obtained during the treatment period showed that radiation doses actually ranged from 7,100 to 64,900 rad. Complete ablation of the hyperfunctioning thyroid tissue and a return to euthyroidism were seen in 7 cats. Partial responses were seen in 2 cats, and 2 cats became hypothyroid. It was concluded that 131I ablation of thyroid tumors was a reasonable alternative in the treatment of hyperthyroidism in cats. The optimal method of dosimetry remains to be determined.

Animals↗
PubMed1980

Incorporation of radioactive tubulin into microtubules at steady state. Experimental and theoretical analyses of diffusional and directional flux.

Subunit flux into porcine brain microtubules at steady state has been studied using both radioactive guanine nucleotide and a radioactive tubulin dimer, [3H]ethyltubulin, which is obtained by a reductive ethylation (Zeeberg, B., Cheek, J., and Caplow, M., (1980) Anal. Biochem. 104, 321--327). We have also determined the molecular rate constants for steady state dimer loss from and addition to the microtubule. This is the first study where the rate for flux of radioactive subunits at steady state has been correlated with the measured molecular rate constants. Also, we derive a theoretical analysis of the observed flux of subunits into a polymer at steady state in pulse and chase experiments; this is used to relate the flux and molecular rate constant to a steady state model. Analysis of our results shows that, at steady state, there is only a small difference in the number of assembly and disassembly events at a given microtubule end (as compared with the total number of events at both ends) in a unit of time; predominant opposite end assembly-disassembly (Margolis, R. L., and Wilson, L. (1978) Cell 13, 1--8) is, therefore, ruled out. The almost complete absence of opposite end assembly-disassembly in the steady state provides a means for very efficient regulation of the microtubule network in vivo, since a small modulation in the relative magnitudes of the molecular rate constants can increase the subunit flux dramatically.

Animals↗
PubMed1981

The use of Radioactive labeling in hemoglobin identification.

The basic approach to radioactive labeling techniques in hemoglobin identification consists of mixing 14C labeled normal carrier globin with 3H labeled unknown globin and carrying out the subsequent separations and purifications looking at the distribution of 3H and 14C radioactivity. This technique was devised to ascertain the amino acid substitution in Hb Indianapolis and was instrumental in solving the structure of Hb Vicksburg. It was also useful in determining the purity of gamma-chains from cultures of human and baboon erythroid progenitors. Another use of this technique would be in identifying aberrant peaks of radioactivity in chain separation chromatograms, such as "pre-peaks".

Carbon Radioisotopes↗
PubMed1982

[Determination of natural radioactive nuclides in the travertine samples from Tamagawa hot spring].

The determination of natural radioactive nuclides was carried out for 7 travertine samples collected from Tamagawa hot spring by means of the non-distructive gamma-ray spectrometry and of the alpha-ray spectrometry. From the former measurements, the relative activity strength, due to 223Ra, 226Ra, and 228Th, and their ratios was obtained in comparison with the photopeak strength due to respective daughters, 228Ac, 214Bi, and 212Pb, and with the results from a monazite sand standard. One travertine sample was engaged to the alpha-ray spectrometric determination of Th isotopes after the chemical purification using a 234Th-yield tracer. On the basis of the resultant absolute content of 228Th, the 228Ra and 228Th contents in the remainder samples were evaluated to be the range of 3 approximately 80 Bq (81 approximately 2160 pCi)/g and 2 approximately 20 Bq (54 approximately pCi)/g respectively. These radioactive nuclides were verified to exist almost within a Hokutolite small crystals up to 90% and there are apparently the radioactive disequilibrium relations between 228Ra and 228Th among freshly deposited travertines. The presence of 227Ac in Hokutolite was also suggested from the detection of 227Th owing to 215Po-alpha peak.

Japan↗
PubMed1981

Acrylonitrile-14C metabolism in rats: effect of the route of administration on the elimination of thiocyanate and other radioactive metabolites in urine and feces.

In Wistar rats, the elimination of the sum of radioactive metabolites of acrylonitrile--14C was not markedly influenced by the rote of acrylonitrile administration. The elimination of thiocyanate, however, was significantly higher after oral (23% of the dose) than after intraperitoneal (4%), subcutaneous (4.6%), or intravenous (1.2%) administration. The elimination of the sum of radioactive metabolites was highest in the first 4 hours after acrylonitrile administration and rapidly decreased, whereas the excretion of thiocyanate reached maximum between hour 8 and 14 after oral or intraperitoneal administration. Less than 1% of radioactivity of the acrylonitrile--14C dose was eliminated in feces irrespective of the route of administration.

Acrylonitrile↗
PubMed1980

Distribution of radioactivity in rats injected with L-14C methionine as studied by whole body autoradiography.

14C-L methionine was given intraperitoneally to rats. The delivered dose was 2.7 mg . kg-1 and the injected activity was 100 microCi . kg-1. Whole body autoradiography was performed on all rats. We noted the highest uptake of radioactivity in the liver and the pancreas. In the liver, there was an accumulation of radioactivity which occurs in the two hours after the injection. In the pancreas, both exocrine and endocrine portions were labelled. All the other organs were labelled but the highest activities are found in high protein turn-over tissues (glands, bone-marrow, spleen). This suggests that methionine is rapidly incorporated into proteins which can explain the persistence of radioactivity in the body of rats injected with this amino acid.

Animals↗
PubMedDate not supplied

Passive cutaneous anaphylaxis: improvement of quantitative analysis by radioactively labelled antigen.

Experiments were performed to improve the quantitative analysis of passive cutaneous anaphylaxis (PCA) by labelling the antigen with radioactive iodine. After intradermal injection of antibodies and intravenous administration of labelled antigen in rats a close correlation was found between the radioactivity measured in skin biopsies and the amount of antigen as well as the amount of antibodies. This direct dependence makes it possible to improve quantitatively the reading of PCA test results. A quantitative correlation was also found when radioactivity is measured over the skin by scanning procedures. Therefore it is not necessary to cut out skin biopsies. Thus the same test animal can be used several times, which minimizes biological variations.

Animals↗
PubMed1979

Lactoperoxidase catalyzed radioiodination of cell surface immunoglobulin: incorporated radioactivity may not reflect relative cell surface Ig density.

Rabbit and mouse splenic lymphocytes were radioiodinated by the lactoperoxidase technique, extracted with non-ionic detergent, immunoprecipitated with high titered rabbit anti-kappa antisera, and compared by SDS-PAGE. Mouse sIg peaks were reproducibly larger in size than rabbit sIg peaks (often greater than 10 times). Neither differences in incorporation of label into the rabbit cell surface, nor differences in average sIg density explain this result. Total TCA-precipitable radioactivity was similar in each species. Estimation of the relative amounts of sIg in the mouse and rabbit showed similar average sIg densities. Differences in detergent solubility, proteolytic lability, or antisera used also do not adequately account for this difference. Thus, these data indicate that radioactivity incorporated after lactoperoxidase catalyzed cell surface radioiodination may not reflect cell surface Ig density. Conclusions about cell surface density based upon relative incorporation of radioactivity should be confirmed by other approaches.

Animals↗