Opposite effects of cations in enhancing and suppressing nucleation in the pathological crystallization of gout

In this paper, we focused on the influence of common serum cations on monosodium urate monohydrate (MSUM) crystal nucleation determined from cumulative probability distributions (CPDs) of solute crystal nucleation events as a function of time. Surprisingly, with an increase in the concentration of additive ions, striking “opposite effects” were observed for cations, enhancing nucleation at first followed by suppressing nucleation at physiological pH and ionic strength. This enhancing nucleation phenomenon cannot be explained based on colloidal theories or simple descriptors, such as ion size, but it is consistent with the cationic efficacy for inducing an increase in the proportion of growth units of MSUM.