Nucleotide Catabolism on the Surface of Aortic Valve Xenografts; Effects of Different Decellularization Strategies.

Extracellular nucleotide metabolism controls thrombosis and inflammation and may affect degeneration and calcification of aortic valve prostheses. We evaluated the effect of different decellularization strategies on enzyme activities involved in extracellular nucleotide metabolism. Porcine valves were tested intact or decellularized either by detergent treatment or hypotonic lysis and nuclease digestion.

Impact of γ-irradiation on extracellular matrix of porcine pulmonary valves.

Background: The extracellular matrix plays an important role in heart valve function. To improve the processing of porcine pulmonary valves for clinical use, we have studied the influence of cryopreservation, decellularization, and irradiation on extracellular matrix components.

Methods: Decellularization was carried out followed by DNAseI/RNAseA digestion and isotonic washout.

Structural integrity of collagen and elastin in SynerGraft® decellularized-cryopreserved human heart valves.

SynerGraft® (SG) decellularized-cryopreserved cardiac valve allografts have been developed to provide a valve replacement option that has reduced antigenicity, retained structural integrity, and the ability to be stored long-term until needed for implantation. However, it is critical to ensure that both the SG processing and cryopreservation of these allografts do not detrimentally affect the extracellular matrix architecture within the tissue. This study evaluates the effects of SG decellularization and subsequent cryopreservation on the extracellular matrix integrity of allograft heart valves.

Guidance for removal of fetal bovine serum from cryopreserved heart valve processing.

Bovine serum is commonly used in cryopreservation of allogeneic heart valves; however, bovine serum carries a risk of product adulteration by contamination with bovine-derived infectious agents. In this study, we compared fresh and cryopreserved porcine valves that were processed by 1 of 4 cryopreservation formulations, 3 of which were serum-free and 1 that utilized bovine serum with 1.4 M dimethylsulfoxide.

Retained structural integrity of collagen and elastin within cryopreserved human heart valve tissue as detected by two-photon laser scanning confocal microscopy.

Cryopreservation is commonly used for the long-term storage of heart valve allografts. Despite the excellent hemodynamic performance and durability of cryopreserved allografts, reports have questioned whether cryopreservation affects the valvular structural proteins, collagen and elastin. This study uses two-photon laser scanning confocal microscopy (LSCM) to evaluate the effect of cryopreservation on collagen and elastin integrity within the leaflet and conduit of aortic and pulmonary human heart valves.

The effects of prostomium and proventriculus removal on sex determination and gametogenesis inTyposyllis pulchra (Polychaeta: Syllidae).

The prostomium alone or the prostomium and proventriculus of reproductiveTyposyllis pulchra were periodically removed at known stages of oogenesis and the gametes were examined by transmission electron microscopy. If the proventriculus and prostomium were simultaneously removed prior to day 3 of the stolonization sequence, before gonial differentiation, the time reruired for stolon formation and concomitant gametogenesis was shortened; the animals, all of which had previously reproduced as females, produced only ultrastructurally normal sperm. Spermatogenesis in these induced males began earlier in the stolonization period than in normal males.