Abstract: Biotin-binding modified avidin-type molecules are provided in which the essential tyrosine residue in the biotin-binding site is modified in such a way that its pKa is decreased in comparison to the pKa of the unmodified tyrosine residue in the corresponding unmodified avidin-type molecule. The avidin-type molecules include: (i) native egg-white avidin; (ii) recombinant avidin; (iii) deglycosylated forms of avidin; (iv) bacterial streptavidin; (v) recombinant streptavidin; (vi) truncated streptavidin; and (vii) derivatives of (i)-(vi) which are modified at sites other than the essential tyrosine residue. The modification is achieved by substitution at one or both ortho positions to the hydroxy radical of the tyrosine residue by radicals such as nitro, halogen, azo and amino. The modified avidin-type molecules can be used in all applications of the avidin-biotin technology.

Abstract: A pseudobioaffinity chromatography adsorbent adapted for use in selectively adsorbing immunoglobulins. In one embodiment, the adsorbent includes: (a) a solid support material; and (b) a ligand immobilized on the surface of the solid support material, said ligand being a compound of the formula ##STR1## wherein Y.sub.1 is selected from the group of S, SCH.sub.3.sup.+, O, NH, NCH.sub.3, CH.sub.2 and CR.sub.1 R.sub.2 wherein at least one of R.sub.1 and R.sub.2 is not hydrogen; wherein each of Y.sub.2, Y.sub.3 and Y.sub.4 is selected from the group of N, NCH.sub.3.sup.+, CH, and CR wherein R is not hydrogen; and wherein at least two of Y.sub.1, Y.sub.2, Y.sub.3 and Y.sub.4 are neither CH.sub.2, CH, CR nor CR.sub.1 R.sub.2.

Abstract: A pseudobioaffinity chromatography adsorbent adapted for use in selectively adsorbing immunoglobulins. In one embodiment, the adsorbent comprises: (a) a solid support material; and (b) a ligand immobilized on the surface of the solid support material, said ligand being a compound of the formula ##STR1## wherein Y.sub.1 is selected from the group consisting of S, SCH.sub.3.sup.+, O, NH, NCH.sub.3, CH.sub.2 and CR.sub.1 R.sub.2 wherein at least one of R.sub.1 and R.sub.2 is not hydrogen; wherein each of Y.sub.2, Y.sub.3 and Y.sub.4 is selected from the group consisting of N, NCH.sub.3.sup.+, CH, and CR wherein R is not hydrogen; and wherein at least two of Y.sub.1, Y.sub.2, Y.sub.3 and Y.sub.4 are neither CH.sub.2, CH, CR nor CR.sub.1 R.sub.2.

Abstract: The invention relates to modified silica, substituted with a variety of substituents. There is provided a product termed primary hydroxyl silica where there are attached to the silica substituents bearing a single hydroxyl group. Furthermore there are provided a wide variety of derivatives of such hydroxy-silica, which are of value in affinity chromatography and for various other uses. The products combine the thermal and mechanical stability of the silica used as carrier with the useful properties of the substituents.

Abstract: Analgesia-effecting 5-hydroxytryptophan derivatives are disclosed of the formulae: ##STR1## wherein R is selected from the group consisting of C.sub.2 -C.sub.16 alkyl, C.sub.3 -C.sub.8 cycloalkyl, C.sub.2 -C.sub.16 alkenyl, C.sub.2 -C.sub.16 alkynyl, aryl containing up to 14 carbon atoms, and arylalkyl containing up to 20 carbon atoms;R.sup.2 and R.sup.2a are each H or R, as defined above;R.sup.3 and R.sup.3a are each H or alkyl containing from 1 to 4 carbons;R.sup.4 and R.sup.4a are each H or alkyl containing from 1 to 4 carbons;and their non-toxic, pharmacologically acceptable acid addition salts.

Abstract: There are provided bifunctional chelating agents, which are analogues of EDTA, conjugates of same with a variety of haptens and conjugates of such conjugates with haptens with certain metals, forming metal complexes. The metal complexes have a variety of uses, among these various assays for the determination of haptens and macromolecules. There is also provided a process for the production of the above. There are provided radioimmunoassays based on the above conjugates with metal cations.

Abstract: Analgesia-effecting 5-hydroxytryptophan derivatives are disclosed of the formulae: ##STR1## wherein R is selected from the group consisting of C.sub.2 -C.sub.16 alkyl, C.sub.3 -C.sub.8 cycloalkyl, C.sub.2 -C.sub.16 alkenyl, C.sub.2 -C.sub.16 alkynyl, aryl containing up to 14 carbon atoms, and arylalkyl containing up to 20 carbon atoms;R.sup.1 and R.sup.1a are each H or methyl;R.sup.2 and R.sup.2a are each H or R, as defined above;R.sup.3 and R.sup.3a are each H or alkyl containing from 1 to 4 carbons;R.sup.4 and R.sup.4a are each H or alkyl containing from 1 to 4 carbons;and their non-toxic, pharmacologically acceptable acid addition salts.

Abstract: There are provided novel labelled derivatives, namely .alpha.-difluoromethylornithine tagged with rhodamine or with biotin. These are of value in analysis and in the cytochemical localization of enzymes.

Abstract: The present invention relates to novel compounds selected from R.sub.1 --COO(CH.sub.2).sub.n --R.sub.2 and ##STR1## wherein R.sub.1 is selected from heterocyclic aromatic and hydrophobic naturally occuring and modified amino acids in the D- and in the L-form, and from peptides, wherein n is an integer of from 1 to 5 and R.sub.2 is selected from unsubstituted and substituted phenyl rings, and from heterocyclic rings, as well as to pharmaceutical compositions for preventing sickling of erythrocytes during sickle cell crisis and for desickling of sickle cells of patients afflicted by sickle cell disease, the active ingredient of which is a compound as defined above.