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Biomedical subjects

M C Parekh

Publications and source records attributed to M C Parekh.

21 records · Page 2Linked to original sources

Chemotaxis of polymorphonuclear leukocytes from donors of different races toward Neisseria gonorrhoeae of three different auxotypes.

Urethral gonorrhea is typified by the presence of large numbers of polymorphonuclear leukocytes, which are presumably attracted to the urethra by an as yet uncharacterized chemotaxin. Culture supernatants from three different auxotypes of Neisseria gonorrhoeae, one requiring arginine, hypoxanthine, and uracil (Arg-,Hyx-,Ura-), one requiring proline, arginine (not satisfied by ornithine), and uracil (Pro-,Arg-[Orn*],Ura-), and one requiring proline (Pro-), were tested for their chemotactic activity against leukocytes from men of two racial groups, white and black. These auxotypes were chosen because the Pro- auxotype is isolated more frequently from black patients, and the Arg-,Hyx-,Ura- and the Pro-,Arg-(Orn*),Ura- auxotypes are isolated more frequently from white patients. Chemotaxis was tested in blind-well chambers in the absence of complement; membranes with a pore size of 3 microns were used. The culture supernatants of the Pro- auxotype were the most chemotactic, while those of the Arg-,Hyx-,Ura- were the least chemotactic when analyzed by a three-way analysis of variance: F = 22.83, df = 2.6, P less than .001. There were no differences in migration with respect to the race of the donor. Gonococcal culture supernatants did not require complement for chemotaxis.

Black People↗

Bactericidal properties of urine for Neisseria gonorrhoeae.

Some human urine is bactericidal for the F-62 strain of Neisseria gonorrhoeae. Gonococci of three auxotypes (Pro-; Arg-, Hyx-, Ura-; and Pro-, Arg-. (Orn*), Ura-) were tested by in-vitro exposure to 31 samples of urine from 14 men. Nineteen of the urine specimens were bactericidal, and 12 were not. Except for one sample, all cidal urines came from five men. Cidal activity was associated with acidic, concentrated urines; it was unaffected by exposure to lowered pH, pronase, heat or cold, and was dialyzable with use of a dialysis membrane with a cut-off molecular weight of 1000. Neutralization of the acid urines removed the antigonococcal activity. Noncidal acid urines became cidal urines when concentrated by lyophilization. Zinc, lysozyme, fluoride ions, and fatty acids are substances that have antibacterial activity and are also present in urine. These substances were examined for antigonococcal activity. Neither zinc salts, fluoride ions, lysozyme, nor fatty acids in concentrations exceeding those found in urine were bactericidal for the gonococci. These results show that sufficiently concentrated, acidic urines kill gonococci by an unknown mechanism.

Dialysis↗