Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0016382 (flushing)
 6,387 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Some data on the synthesis and characterization of poly(HEMA-MAC) and its applications for fertility control are presented. This new technique involves the use of the polymer, which when injected into the vas deferens lowers the pH sufficiently so as to kill the spermatozoa passing through. The polymer provides an acidic environment for a prolonged time and slowly erodes. The fertility may be restored after complete solubility of the polymer itself over a period of time or by flushing it with a suitable solvent. It is a nonsurgical, nonocclusive, and reversible method of male contraception. In regard to the experimental procedure, copolymerization of HEMA with MAC (35% by weight) in methanol was carried out in a nitrogen atmosphere in glass ampules. Irradiation was performed in a cobalt-60 radiation chamber. All the samples were irradiated at a dose rate of 130 rad/s for a total dose of 0.936 Mrad at room temperature. For studying the spermicidal actions of the copolymer, epididymal fluid from the male rat was collected, diluted 1:10 with Ringer-fructose buffer and microscopically examined. Small swollen pieces of poly(HEMA-MAC) copolymer as well as poly(HEMA) homopolymer were then added to the epididymal fluid and the effect on the spermatozoa was noted. The spermicidal action "in vitro" was indicated by the loss of motility of the spermatozoa immediately on coming in contact with the poly(HEMA-MAC). The spermatozoa remained immotile even after the removal of the copolymer, indicating that they were dead. The polymer treated spermatozoa did not take up any supravital stain confirming that they were killed. This effect was absent only when poly(HEMA) was used. These results clearly show that the spermicidal activity is mainly due to the carboxylic groups of MAC. Possibly the low pH environment due to the ionization of carboxylic groups is responsible for killing the spermatozoa. For all the experiments the injection of the polymeric solution into the vas deferens was given only by exposing the vas deferens, but it is reported that in humans injection into the scrotal wall is possible. The new technique has all the characteristics which can lead to an ideal contraceptive method. Preliminary results of "in vitro" experiments on human spermatozoa with these hydrogels are encouraging.
 ...
PMID:Novel mode of contraception using polymeric hydrogels. I. 705 60