Determination of digoxin in human-serum

Summary Four immunological assays (RIA, ELISA, EMIT, FPIA) for digoxin were characterized with respect to reproducibility, detection limit, selectivity, and accuracy, followed by the comparison with HPLC. Afterwards the serum samples of nearly 60 patients were analyzed by these five methods.It could be shown, that the reproducibility at 2 g/l was fairly good for all methods. Reliable analysis in the lower concentration range (< 1 g/l) was difficult with two assays, because of insufficient detection limits. There was a marked cross-reactivity to other digitalis glycosides. Moreover, correlation between the immunological methods and in comparison to the HPLC-method was low.

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Bestimmung von Digoxin in HumanserumVergleich einiger immunologischer Assays mit einer vorgeschlagenen HPLC-Referenzmethode

     

Radioimmunoassay

Biologically active substances are often effective in nanogram or even smaller quantities. Investigations of their mode of action therefore require highly sensitive microanalytical methods of detection. Chemical, chromatographic or spectrometric methods frequently lack the required sensitivity; it was only after the discovery of the radioimmunoassay (RIA) that quantitative determination of minute amounts of substances in the presence of a millionfold excess of other compounds became possible. The radioimmunoassay combines the extreme sensitivity of detection of radioactively labeled substances with the high specificity of immunological reactions. The superiority of radioimmunological methods over other analytical techniques rests upon their sensitivity, specificity, facile application, and especially their broad general scope.     

Non linear fermion mass relations inE 6

The two generation version of theE ₆ unified model exhibits a curious non-linear mass relation for fermions, which until now has no group-theoretical explanation. Here we show that this relation is still valid in the three generation version. A new mass relation involving the trace of mass matrices square is indicated. Its derivation is immediate.     

Cross sections and mean charges of jets inp\bar p collisions

Two jet reactions at collider energies within the frame of QCD are studied. Cross sections and mean charges are shown for both cases when one or two jets are observed. Scaling violations are introduced by means of the Altarelli-Parisi equation for a completely asymmetric sea. The effects due to scaling violation, gluon distribution and gluons in the final state are computed.     

Glasses in the system PSeTl: An NMR study of chemical bonding properties

Glasses in the ternary system PSeTl have been studied using ³¹P, ²⁰³Tl, and ²⁰⁵Tl NMR. Information has been obtained from the composition dependence of the phosphorus linewidth, the thallium chemical shift, the pseudo-exchange interaction, and from NMR and X-ray data of crystallized samples. At Tl/P ratios smaller than 1, Tl appears to be more covalently bonded than in AsSeTl glasses, and the introduction of thallium results in a strengthening of the structure, which may be combined with a conversion of phosphorus from three-to four-coordination. Glasses with Tl/P > 1 show increasing bond covalency and important TlTl interactions as the thallium content increases; upon annealing TlPSe₂ is formed. In this region introduction of thallium tends to weaken the glass structure, in agreement with observed properties.     

Inelastic neutron scattering from the quasi-one-dimensional conductor K1.75[Pt(CN)4]·1.5H2O

Neutron inelastic scattering has been used to study the longitudinal and one of the transverse acoustic phonons, propagating along the [001]¹ direction in triclinic K_1.75[Pt(CN)₄]·1.5H₂O. This material appears to be a quasi-one-dimensional conductor, with a commensurate distortion. We observe a reasonably well defined Kohn anomaly, which shows little temperature dependence between 80 and 300 K.     

Bis-1,3-diol type liquid crystals from pentaerythritol [1]

Several esters and ethers of pentaerythritol have been prepared. Four of them, containing each a 1,4-trans-disubstituted cyclo-hexane unit and three hydroxyl functions, emerge as examples of a novel type of thermotropic, intermolecularly hydrogen bridge-supported multiol mesogens exhibiting the smectic A phase. A new case of a heteroatom effect preventing mesophase formation by causing stable intramolecular hydrogen bonding situations will also be discussed.