The invention refers to a compound of the formula: wherein Q is Te or Se; t is 1 or 0; us is 1 or 0; v is 1 or 0; R, R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈, and R₉ are the same or different and are independently selected from the group consisting of hydrogen, hydroxyalkyl of 1 to 5 carbons, hydroxy, alkyl of from 1 to 5 carbon atoms, halogen, haloalkyl of 1 to 5 carbon atoms, carboxy, alkylcarbonylalkyl of 2 to 10 carbons, alkanoyloxy of 1 to 5 carbon atoms, carboxyalkyl of 1 to 5 carbon atoms, acyl, amido, cyano, amidoalkyl of 1 to 5 carbons, N-­monoalkylamidoalkyl of 2 to 10 carbons, N,N-dialkylamido­alkyl of 4 to 10 carbons, cyanoalkyl of 1 to 5 carbons, alkoxy of 1 to 5 carbon atoms, alkoxyalkyl of 2 to 10 carbon atoms and -COR₁₀ wherein R₁₀ is alkyl of from 1 to 5 carbons; and X is halogen; while the potassium salt is illustrated, it is understood that other pharmaceutically acceptable salts are within the scope of the invention in a method of stimulating the production of lymphokine by administering to a host an effective amount of such a compound and thus, also treating acquired immune deficiency syndromes, pharmaceutical compositions containing such compounds and a process of preparing the compounds by contacting an alykene glycol with tellurium tetrachloride in the presence of a potassium or ammonium halide at elevated temperatures.

This invention is directed to a radiation sensitive silver halide emulsion comprising a macroheterocycle having an acid function and to an element containing such emulsion. The macroheterocycle comprises at least two atoms of sulfur or selenium, each of which atoms being separated from one another by a chain of at least two carbon atoms. Such compound acts as a solvent and as a growth modifying agent for silver halide grains. Also described is a process for modifying the growth of silver halide grains.