Mandel G S, Halverson P B, Mandel N S
Department of Medicine, Medical College of Wisconsin, Milwaukee.
Scanning Microsc. 1988 Jun;2(2):1177-88.
The kinetics of calcium pyrophosphate dihydrate (CPPD) crystal growth was studied by allowing calcium and pyrophosphate (PPi-4) ions to diffuse through a denatured collagen matrix (biological grade gelatin) in the presence of either ferric or ferrous ions. Ferric and, to some extent, ferrous ions blocked the migration of the PPi-4 diffusion gradient. This retardation in the [PPi-4] gradient led to numerous changes in the patterns of CPPD crystal formation. At the initial stages of crystal growth, the iron ions induced more crystal growth compared to control. At later incubation times, ferrous and ferric ions enhanced crystal growth at the expense of crystal nucleation. The presence of both ferrous and ferric ions resulted in the more rapid formation of the two crystals observed in vivo, triclinic CPPD and monoclinic CPPD. Further, both ferrous and ferric ions also reduced the solubility of the crystalline material in the broad diffuse band which formed when the Ca+2 and PPi-4 gradients first met. In this system, the presence of either ferrous or ferric ions increased the amount of hydroxyproline included in the crystalline precipitates. Iron was also incorporated into the crystals, particularly into the triclinic CPPD and monoclinic CPPD crystals.
通过让钙离子和焦磷酸根离子（PPi-4）在存在铁离子或亚铁离子的情况下扩散穿过变性胶原基质（生物级明胶），研究了二水合焦磷酸钙（CPPD）晶体生长的动力学。铁离子以及在一定程度上亚铁离子阻碍了PPi-4扩散梯度的迁移。[PPi-4]梯度的这种延迟导致CPPD晶体形成模式发生许多变化。在晶体生长的初始阶段，与对照相比，铁离子诱导了更多的晶体生长。在后期孵育时间，亚铁离子和铁离子以牺牲晶体成核为代价增强了晶体生长。亚铁离子和铁离子的存在导致在体内观察到的两种晶体，三斜晶系CPPD和单斜晶系CPPD更快形成。此外，亚铁离子和铁离子还降低了晶体物质在Ca+2和PPi-4梯度首次相遇时形成的宽扩散带中的溶解度。在该系统中，亚铁离子或铁离子的存在增加了结晶沉淀物中羟脯氨酸的含量。铁也掺入到晶体中，特别是掺入到三斜晶系CPPD和单斜晶系CPPD晶体中。
