Compounds In Biological Tissues Research Articles

Extraction procedure for the measurement of butyltin compounds in biological tissues using toluene, HBr, and tropolone.

Extraction procedure for the measurement of butyltin compounds in biological tissues using toluene, HBr, and tropolone.

Determination of the concentration of complex boronated compounds in biological tissues by inductively coupled plasma atomic emission spectrometry.

The application of inductively coupled plasma atomic emission spectrometry (ICP-AES) to the determination of the concentration of complex boron-containing compounds in biological tissue samples is described. Tissue digestion is achieved with perchloric acid and hydrogen peroxide in 1 hr at 75 degrees C. The ICP-AES method gave a linear response for elemental boron concentration in the range 0.05 to 100 ppm and does not require the reduction of the boron to a simple species, such as boric acid. Complete recovery of boron in complex boron cluster compounds was obtained. The procedure has been applied to the determination of the boron content in compounds synthesised for neutron capture therapy and is suitable for use in biodistribution studies of such compounds.

Short Communication: Trifluorothymidine localization in the rabbit cornea by secondary ion mass spectrometry imaging microanalysis

Imaging microanalysis by secondary ion mass spectrometry is a sensitive surface analytical technique that allows the detection and localization of elements and compounds in biological tissues. We report the detection by this approach of intracorneal trifluorothymidine following topical administration in rabbit with normal cornea. The presence of trifluorothymidine is revealed using 19F as a marker, allowing the acquisition of ultrastructural microanalytical images without using radioactive tracers.

Nitrogen-14 nuclear magnetic resonance spectroscopy of mammalian tissues.

The use of 14N nuclear magnetic resonance (NMR) to monitor the concentrations of nitrogenous compounds in biological tissues was investigated. 14N-NMR spectra were collected in vivo and in vitro from several tissues of the rat and rabbit. Many nitrogen-containing compounds were detected, including urea, NH+4, trimethylamines, and several amino acids. In general, the compounds detected had approximately tetrahedral symmetry about the 14N nucleus and concentrations in the millimolar range. A problem that may limit the usefulness of 14N-NMR in intact tissue is the rapid exchange of nitrogen compounds in solution with those bound to sites on macromolecules. Such interactions tend to broaden the 14N resonance signal considerably. The binding of urea to intra- and extracellular proteins is presented as a specific example of this phenomenon. A particularly interesting finding was the high concentration (approximately 90 mM) of trimethylamine compounds in the renal inner medulla. We propose that 14N-NMR is a potentially useful technique for noninvasive detection of specific nitrogen-containing compounds in intact biological tissues.

Soil Animals as Vectors of Organochlorine Insecticides for Ground-Feeding Birds

The uptake of small sublethal doses of organochlorine pesticides by birds appears now to be quite a common phenomenon, but the pathways have been, for the most part, little examined. This paper discusses some of the ecological factors affecting the uptake and passage of organochlorine compounds in terrestrial ecosystems with particular reference to soil animals and ground-feeding birds such as the Robin (Erithacus rubecula), Skylark (Alauda arvensis), Lapwing (Vanellus vanellus), Starling (Sturnus vulgaris), thrushes (Turdus spp.) and corvids (Corvus spp.) for which animals form a large fraction of the diet. Blackbird (Turdus merula) and the Kestrel (Falco tinnunculus), both of which take large numbers of invertebrates, though the Blackbird is an omnivore with a partiality for fruit and the Kestrel a raptor feeding largely on small mammals. The ppm intervals chosen follow approximately a log scale which is rounded to the nearest convenient figures. The two species cannot be compared in detail since liver alone was used for analysis of the Kestrels and mixed viscera, which consisted of liver, heart and spleen (and possibly gut in some instances), in the Blackbirds. Both species came from a large number of counties but as the birds were generally found dead and the cause of death unknown neither set can be assumed to be a fair sample of the population. However, several features can be deduced. First, that both species had picked up residues of all the common organochlor- ine pesticides used in this country and secondly, apparently in contrast to the American situation, dieldrin and heptachlor epoxide residues are commonly present. DDT itself features very insignificantly but the preponderance of DDE indicates a large original DDT source. The relatively high amounts of heptachlor epoxide and low amounts of BHC contrast with the annual depositions of these compounds (see Strickland 1965) and reflect probably the biased nature of the samples as well as the known properties of relative persistence of these compounds in biological tissues.