Nargis Nizam Ashraf, Nisar Ahmed Siyal, Sharjeel Sultan, Mohammad Idrees Adhi.
Comparison of Efficacy of Storage of Amniotic Membrane at -20 and -80 Degrees Centigrade.
J Coll Physicians Surg Pak Jan ;25(4):264-7.

Objective: To compare the efficacy of storage of amniotic membrane at -20 and -80 degrees centigrade. Study Design: Interventional quasi-experimental study. Place and Duration of Study: Department of Ophthalmology, Unit 1, Dow University of Health Sciences and Civil Hospital, Karachi, from January 2009 to December 2010. Methodology: Amniotic membrane was obtained from patients undergoing elective Caesarean section screened for HIV, Hepatitis B and C and gave informed consent. It was washed with solutions containing benzyl penicillin, streptomycin and amphotericin B and frozen at -20 degrees centigrade for upto 6 weeks or at -80 degrees centigrade for upto 6 months. Fisher's exact test was used to check significance. P-value less than 0.05 was considered as significant. Results: Amniotic membrane was stored at -20 degrees centigrade on four occasions and was used in 25 (48.07%) patients. On 3 other occasions it was stored at -80 degrees centigrade and was successfully used in 27 (51.92%) patients. The association between different degrees of storage of graft and type of cases is insignificant (p = 0.99). Conclusion: Compared to use of fresh amniotic membrane use of amniotic membrane stored at -20 and -80 degrees is safe and cost effective. It also excludes the chances of disease transmission. Although freezing at both temperatures is equally efficacious, freezing at -80 degrees centigrade can preserve the graft upto 6 months compared to -20 degrees centigrade which can be used only for 6 weeks.

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