B.G. Dekker

The influence of experimental conditions on the formation of various 99mTc(Sn)EHDP complexes

Abstract The influence has been investigated of the pH and the Sn(II)-concentration on the yield of formation of the complexes 99mTc(IV)-Sn-EHDP2 and 99mTc(IV)-Sn-EHDP, which are the most important products formed during labeling of EHDP with 99mTc. Regression equations are derived and used to find optimal conditions.

Gel chromatographic separation and identification of the Tc(Sn)EHDP complexes using the radiotracers 32P, 99(m)Tc, 113Sn

Abstract The composition of the reaction mixture for the labeling of EHDP with technetium has been investigated with gel chromatography using the radiotracers 32 P(EHDP), 99 m Tc, 99 Tc and 113 Sn. The various elution peaks have been determined using an iterative Gaussian curve fitting programme. The amounts of 32 P, 99 m Tc, 99 Tc and 113 Sn present in the elution peaks and estimates of the molecular weight were used to determine the composition of the 99 Tc(Sn)EHDP complexes. At least five 99 Tc(Sn)EHDP complexes were found. The formulae of the complexes are probably as follows: Tc(IV)-EHDP, Tc(IV)-Sn(IV)-EHDP, Tc(IV)-EHDP 2 , Tc(IV)-Sn(IV)-EHDP 2 and Tc(IV)-Sn(IV)-EHDP 3 .

The influence of the method of preparation of the bone scanning agent 99mTc(Sn)EHDP on its tissue distribution in the rat

The tissue distribution in the rat of the bone scanning agent 99mTc(Sn)EHDP is investigated by three methods, viz. by dissecting the animals 3 and 24 h post injection, by scanning the animals with a rectilinear scanner and by whole body autoradiography, particular of micro-sections of the skeleton. The effect of varying the experimental conditions in the preparation of the bone scanning agent (pH and concentrations of Sn(II) and EHDP) is investigated. In some of the experiments additional amounts of Sn(II) and EHDP are added to the reaction mixture after the preparation of the bone scanning agent. In this way the influence of the Sn(II) and EHDP concentrations on the composition of the bone scanning agent, and their influence as such on tissue uptake can be separately investigated. The 99mTc-uptake in bone is compared with the distribution of the 99mTc over the two main products in the reaction mixture, viz. 99mTc(IV)-Sn-EHDP2 and 99mTc(IV)-Sn-EHDP. In addition, the stability in vitro of some of the preparations in urine and plasma and the in vivo binding of the 99mTc to plasma proteins are determined. A procedure for the preparation of the bone scanning agent is recommended.

Gel-chromatographic analysis of 99mTc-labeled human serum albumin prepared with Sn(II) as the reductant

The labeling of human serum albumin (HSA) with 99mTc using Sn(II) as the reductant has been reinvestigated in view of the possibility of formation of Sn-Tc colloids. Preparations of 99mTc-HSA and mixtures of 99mTc-TcO-4 with Sn(II)Cl2 have been analyzed by means of gel chromatography using various gel matrices and eluents. No Sn-Tc colloids could be eluded from samples of 99mTc-HSA preparations. The percentage of labeling was about 90%. A comparative investigation of a number of gel-chromatographic systems for the detailed analysis of 99mTc-HSA has been made. It is found that a long column with Sephadex G-200 gives the best results.

The valence state of technetium-99 in its complexes with bleomycin, 1-hydroxy-ethylidene-1,1-diphosphonate and human serum albumin

The valence state of technetium-99 in its complexes with bleomycin, 1-hydroxy-ethylidene-1,1-diphosphonate and human serum albumin was determined by titration of 99TcO4− with Sn(II) in the presence of these complexing agents. Both direct titration, and addition of an excess of Sn(II) and back-titration with iodine was employed.

The influence of experimental conditions on the efficiency of labeling of bleomycin with 99Tcm, using Sn(II) as the reductant.

Abstract The influence of the pH and of the Sn(II) and bleomycin concentrations on the efficiency of the labeling of bleomycin with 99Tcm has been investigated by means of a three-factor factorial design, in duplicate. The equation which describes the response surface, i.e. the labeling efficiency as a function of the experimental variables, has been derived. From this equation the conditions were found which yield 94% labeling.

Activated carbon as an adsorbent for the separation of low-molecular alkyl halides from ground water in the production of drinking-water. I: An accurate in the production of drinking-water. I: An accurate method for the determination od adsorption isotherms, and its application to virgin and regenerated activated carbons

An accurate method has been developed for the determination of the adsorption isotherm of trichloroethene on activated carbon over the concentration range 1 – 100 μg/1. This method has been applied to 18 samples of activated carbon of different types, both virgin and regenerated. All samples of activated carbon were characterized by determining the apparent density of the granular and the powdered carbon, and the Fe, Mn, Ca and Mg contents were determined for eight samples. The best way to describe the results mathematically has been investigated, and an improvement to the well-known Freundlich equation established.

The influence of experimental conditions on the association constant for binding of vitamin B12 by human intrinsic factor coupled to Sepharose 4B.

The association constant for binding of vitamin B12 (cyanocobalamin) by human intrinsic factor coupled to Sepharose 4B and the concentration of binding sites of the coupled intrinsic factor have been measured as a function of pH, temperature, ionic strength and the presence of various (ionic and non-ionic) components in the solution.

A study on the interaction of IgA with insolubilized a-IgA-antibody

Abstract The influence of experimental conditions on the association constant of the interaction between IgA and insolubilized a-IgA has been studied by means of radioimmunoassay. The nature of the antigen-antibody interaction is discussed on the basis of the results of variance analysis of the data.