Reproduction and Larval Development of Typosyllis pulchra (Berkeley & Berkeley) (Polychaeta: Syllidae)

The reproductive biology of Typosyllis pulchra from the coast of Washington has been investigated based on observations of animals in the field and stolonization in the laboratory by both field-collected and cultured animals. Like most Syllinae, T. pulchra reproduces by stolonization, i.e., each individual produces 3-4 posterior, detachable, gamete-bearing stolons during consecutive 30-day intervals. Although some regenerating segments are incorporated into the stolons, in this species new stolons consist primarily of stock body segments. Reproductive animals occur in the field from late January through July; maximum reproductive activity is between April and June. Long days apparently promote reproduction, but lunar synchronization of spawning could not be demonstrated. Larval development is described based on light and scanning electron microscopy. Fertilization is external; developing larvae settle within 75 hr. The development of cephalic structures (eyes and antennae) is precocious compared to other Syllinae that have been studied, and the sequence of parapodium formation is unusual

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. In the first serum-free group, bovine serum was simply removed from the cryopreservation formulation. The second serum-free formulation had a higher cryoprotectant concentration, i.e. 2 M dimethylsulfoxide, in combination with a serum-free solution. A colloid, dextran 40, was added to the third serum-free group with 2 M dimethylsulfoxide due to theoretical concerns that removal of serum might increase the incidence of tissue cracking. Upon rewarming, the valves were inspected and subjected to a battery of tests. Gross pathology revealed conduit cracking in 1 of 98 frozen heart valves. Viability data for the cryopreserved groups versus the fresh group demonstrated a loss of viability in half of the comparisons (p < 0.05). No significant differences were observed between any of the cryopreserved groups, with or without bovine serum. Neither routine histology, autofluorescence-based multiphoton imaging nor semiquantitative second-harmonic generation microscopy of extracellular matrix components revealed any statistically significant differences. Biomechanics analyses also revealed no significant differences. Our results demonstrate that bovine serum can be safely removed from heart valve processing and that a colloid to prevent cracking was not required. This study provides guidance for the assessment of changes in cryopreservation procedures for tissues