In multistep reactions, stability of intermediates is critical to the rate of product formation and a significant factor in generating kinetic traps. The capsid protein of cowpea chlorotic mottle virus (CCMV) can be induced to assemble into spherical particles of 30, 60, and 90 dimers. Based on examining assembly kinetics and reaction end points, we find that formation of uniform, ordered structures is not always a result of reactions that reach equilibrium. Equilibration or, alternatively, kinetic trapping can be identified by a straightforward analysis. Altering the assembly path of "spherical" particles is a means of controlling the distribution of products, which has broad applicability to self-assembly reactions.

Purpose The association between vitamin D and prostate biopsy outcomes has not been evaluated. We examine serum vitamin D levels with prostate biopsy results in men with abnormal PSA and/or digital rectal examination. Experimental Design Serum 25-hydroxyvitamin D (25-OH D) was obtained from 667 men, age 40-79, prospectively enrolled from Chicago urology clinics undergoing first prostate biopsy. Logistic regression was used to evaluate the associations between 25-OH D status and incident prostate cancer (PCa), Gleason score, and tumor stage. Results Among European American (EA) men, there was an association of 25-OH D < 12 ng/ml with higher Gleason score ≥ 4+4 (OR = 3.66 [1.41, 9.50], p = 0.008) and tumor stage (stage ≥ cT2b vs. ≤ cT2a, OR = 2.42 [1.14, 5.10], p = 0.008). In African American (AA) men, we find increased odds of PCa diagnosis on biopsy with 25-OH D < 20 ng/ml (OR = 2.43 [1.20, 4.94], p = 0.01). AA men demonstrated an association between 25-OH D < 12ng/ml and Gleason ≥ 4+4 (OR = 4.89 [1.59, 15.07]; p = 0.006). There was an association with tumor stage ≥ cT2b vs. ≤ cT2a (OR: 4.22, [1.52 – 11.74], p = 0.003). Conclusions In AA men, vitamin D deficiency was associated with increased odds of PCa diagnosis on biopsy. In both EA and AA men, severe deficiency was positively associated with higher Gleason grade and tumor stage.