(1) Biliary and urinary excretion of five tritium-labelled cardiac glycosides, i.e.
(2) Tritium-labeled ribonucleic acid precursors, including cytidine, uridine, and orotic acid, were injected into rats with dated pregnancies (14 to 21 days) and virgin rats.
(3) Ovarian aromatase activity, assessed by incubating the homogenised ovaries of treated rats with tritium-labelled androstenedione (0.2 microM) or testosterone (1 microM), indicated that residual enzyme activity was reduced compared with controls.
(4) The adenylate cyclase activator forskolin as well as 8-bromo-cyclic AMP enhanced the electrically evoked release of 3H-noradrenaline and 3H-5-hydroxytryptamine from superfused rat neocortical slices and that of 3H-dopamine from neostriatal slices with comparable EC50's of about 0.5 and 50 microM, respectively, without affecting spontaneous tritium efflux.
(5) It was also found that tritium release also occurred, although to a lesser extent, when tissues were fixed in glutaraldehyde or osmium tetroxide using collidine as a buffer, and this release was not significant when collidine was applied to previously fixed tissues.
(6) The standardised mortality ratios were 889 (six deaths) in employees monitored for contamination by tritium, 254 (nine deaths) in those monitored for contamination by other radionuclides, and 385 (nine deaths) in those with dosimeter readings totalling more than 50 mSv (5 rem); but the same nine subjects tended to account for each of these significantly raised ratios.
(7) 3T3 cells were also used for the incorporation of tritium-thymidine.
(8) Isolated hepatocytes carry out the N-demethylation of dansylamide at near linear rates for up to 8 h. This reaction was measured by following the release of tritium into water on hydroxylation of 3H-labeled methyl groups.
(9) Similar low deuterium and tritium isotope effects were measured with a purified rat liver cytochrome P-450 preparation and horseradish peroxidase.
(10) The effects of alpha-adrenoceptor agonists and antagonists on the electrically (slices) or potassium-evoked (synaptosomes) tritium overflow were studied.
(11) During the monodirectional conversion of D-[2-3H]mannose 6-phosphate to D-fructose 6-phosphate and D-fructose 1,6-bisphosphate, the reaction velocity is one order of magnitude lower than with D-[U-14C]mannose 6-phosphate and little tritium (less than 6%) is transferred intramolecularly.
(12) The 72-hour cumulative urinary excretion of total tritium was 28.2% of the administered dose and only 38.3% of this resided in unchanged HHT.
(13) However, higher doses of diltiazem (60 microM) reduced the tritium overflow elicited by RNS or Vt but enhanced that caused by KCl.
(14) The substrate was labelled by the catalytic addition of tritium to cerebroside sulphate.
(15) In contrast, in synaptosomes superfused with Ca(2+)-free Krebs-Henseleit solution containing 15 mM K+ throughout, ethanol did not affect the tritium overflow evoked by 2 min introduction of 75 microM Ca2+ into the superfusion fluid.
(16) We have assessed a multiwire camera for the high speed, quantitative autoradiography of tritium-labelled substances in two-dimensional systems.
(17) Dipyridamole (5 x 10(-5) M) and erythro-9-2-hydroxy-3 nonyl adenosine (EHNA) (10(-4) M) also reduced tritium release.
(18) Tritium thymidine incorporation rates inform about DNA-synthesis.
(19) GR43175 (1 x 10(-8) to 1 x 10(-5) M) inhibited the electrically evoked release of tritium from renal noradrenergic nerves but did not affect the basal (non-stimulated) release of tritium or perfusion pressure.
(20) The activity of aromatase in microsomal preparations was assayed by determining the rate of incorporation of tritium from 1-[3H]androstenedione into [3H]water.
Trivium
Definition:
(n.) The three " liberal" arts, grammar, logic, and rhetoric; -- being a triple way, as it were, to eloquence.
(n.) The three anterior ambulacra of echinoderms, collectively.