{'fraction_non_alphanumeric': 0.05366207396664249, 'fraction_numerical': 0.0340826686004351, 'mean_word_length': 4.7740585774058575, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
A simplified technique for the cryopreservation of vein allografts.

OBJECTIVES
we assessed the effects of cryopreservation on smooth-muscle cell injury in human vein.


MATERIALS AND METHODS
long saphenous vein was collected during surgery and cryopreserved. Smooth-muscle cell damage was assessed after thawing by in situ detection of fragmented DNA. The presence of cryoprotectant (10% dimethyl sulphoxide, DMSO), cooling and warming rates, and the rate of cryoprotectant removal after thawing were examined.


RESULTS
control veins exhibited damage in 8.5% (95% confidence interval (CI) 4.7 to 13.4%,n=13) of smooth-muscle cells compared with 27.7% (95% CI 23.2 to 32.4%, n=115) in vein frozen in 10% DMSO (p=0.001). In the presence of DMSO, damage to smooth-muscle cells was independent of the rates of cooling (p=0.72) and warming (p=0.45). The rate of dilution to remove the cryoprotectant after thawing also had no effect on cell damage (p=0.64). In the absence of cryoprotectant, cell damage was doubled to approximately 50% by slow rather than rapid warming (p=0.01).


CONCLUSION
cooling rate, and the presence of a cryoprotectant, has little effect on smooth-muscle damage, provided that the tissue is warmed rapidly. Slow warming, in the absence of DMSO, causes substantial damage. These results suggest that simplified methods of vein cryopreservation are feasible.