South African blacks rarely form kidney stones compared
with whites. This study investigated whether
purified urinary prothrombin fragment 1 (UPTF1) derived
from blacks is a more potent inhibitor of calcium
oxalate crystallisation than that from whites. UPTF1
was purified from the urine of both population groups
and their inhibitory activities were compared in a
cross-over design in which each protein was tested in
ultrafiltered urine from both population groups. Coulter
Multisizer, [14C]-oxalate deposition and scanning
electron microscopy experiments were used to monitor
crystallisation. The study has demonstrated for the
first time that UPTF1 promotes nucleation and that inhibitory
activity is synergistically dependent upon
urine composition. The activity of the whites' UPTF1
was greater than that of the blacks in the whites' urine
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Print ISSN: 1434-6621
Volume: 40, 09/2002
Pages: 930 - 936