The impact of circulating cholesterol crystals on vasomotor function: implications for no-reflow phenomenon.

Objectives: The purpose of this study was to determine if cholesterol crystals can injure the endothelial surface by their jagged edges altering vasoreactivity and contributing to no-reflow after intervention.

Background: After plaque rupture, cholesterol crystals are released into the circulation and flow downstream contacting the arterial wall.

Methods: Both carotid arteries from 22 rabbits were placed in a dual perfusion chamber and challenged with norepinephrine followed by acetylcholine and nitroprusside.

Reactivity of ferritin and the structure of ferritin-derived ferrihydrite.

Background: In nature or in the laboratory, the roughly spherical interior of the ferritin protein is well suited for the formation and storage of a variety of nanosized metal oxy-hydroxide compounds which hold promise for a range of applications. However, the linkages between ferritin reactivity and the structure and physicochemical properties of the nanoparticle core, either native or reconstituted, remain only partly understood.

Scope Of Review: Here we review studies, including those from our laboratory, which have investigated the structure of ferritin-derived ferrihydrite and reactivity of ferritin, both native and reconstituted.

Characterization and surface reactivity of ferrihydrite nanoparticles assembled in ferritin.

Ferrihydrite nanoparticles with nominal sizes of 3 and 6 nm were assembled within ferritin, an iron storage protein. The crystallinity and structure of the nanoparticles (after removal of the protein shell) were evaluated by high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), and scanning tunneling microscopy (STM). HRTEM showed that amorphous and crystalline nanoparticles were copresent, and the degree of crystallinity improved with increasing size of the particles.

Iron and cobalt oxide and metallic nanoparticles prepared from ferritin.

Metallic Fe and Co and Fe- and Co-based oxide nanoparticles were prepared by a novel method utilizing the biologically relevant protein ferritin. In particular, iron and cobalt oxyhydroxide nanoparticles were assembled within horse spleen and Listeria innocua derived ferritin, respectively, in the aqueous phase. Ferritin containing either Fe or Co oxide was transferred and dried on a SiO2 support where the protein shell was removed during exposure to a highly oxidizing environment.

First-Row Transition-Metal Complexes of the 1-Methoxycyclobutenedionate(1-) Ion.

The synthesis and characterization by single-crystal X-ray crystallography of a series of monomeric first-row transition-metal complexes with the 1-methoxycyclobutenedionate(1-) ligand are described. The isomorphous compounds [M(CH(3)OC(4)O(3))(2)(H(2)O)(4)] (M = Mn, Co, Ni, Zn) are C(2) symmetric and crystallize in the monoclinic space group C2/c. The metal atom in each of these complexes is six-coordinate with two cis 1-methoxycyclobutenedionate(1-) ligands, the methoxy substituent being oriented cis with respect to the ligating oxygen atom.

Attempted Syntheses of Transition Metal and Lanthanide (Dialkylamino)squarates. The Hydrolysis Problem.

Reaction of 1-amino-2-methoxycyclobutenedione with M(NO(3))(2).xH(2)O (M = Mn, Co, Ni, Cu, Zn) in aqueous solution results in the formation of the squarates M(C(4)O(4)).4H(2)O and/or M(C(4)O(4)).