Abstract: In an improved method for producing a surface graft of a hydrophilic polymer upon a preformed solid or semi-solid polymer substrate having hydroperoxide groups along its surface, n-vinyl pyrrolidone is utilized as the surface-grafting monomer, the substrate is selected to be insoluble in n-vinyl pyrrolidone, and the polymerization is carried out in aqueous alkaline conditions utilizing a combination of metal salts to provide a variable valence metal ion in a reduced state capable of oxidizing to suppress homopolymerization of the monomer in the solution.When the substrate is at least partially soluble in the n-vinyl pyrrolidone, an ethylenically unsaturated monomer having a higher reactivity with the substrate than n-vinyl pyrrolidone is added to the alkaline polymerization solution as a "seeding" monomer. Addition of the "seeding" monomer results in a surface-grafted copolymer effectively externalized from the substrate.

Abstract: Disclosed is a method for dissolving cholesterol-rich calculi, most preferably gallstones in vivo, comprising contacting the calculus with a fluid compound of the formula R-X, R having 2 to 4 carbon atoms with substituents consisting of hydrogen of halogen, X being halogen, and wherein if X is fluorine, at least one substituent is selected from the group consisting of hydrogen, chlorine, bromine, or iodine. Usually R-X is 2-bromo-2-chloro-1,1,1-trifluoroethane (also referred to as Halothane.) Other compounds of particular interest are 2-chloro-1,2,-dibromo-1,1,2-trifluoroethane, 1-bromo-2-chloro-1,1,2-trifluoroethane, 2,3-dibromo-1,1,1-trifluoropropane, 2-iodo-1,1,1-trifluoroethane, 1,2-dichloro-1,1-difluoroethane, 1,1,2-trichloro-2,3,3-trifluorocyclobutane, hexafluoro-1,1,3,4,-tetrachlorobutane, 1,1,1-trichlorotrifluoroethane, and 1,2-dibromo-tetrafluoroethane. Furthermore, Halothane and MtBE in combination effectively dissolve cholesterol-rich calculi.