Synthetic media for preservation of corneal tissues deemed for endothelial keratoplasty and endothelial cell culture.

PURPOSE: To compare the difference between various endothelial graft preparation methods and endothelial cell culture from tissues that are preserved in serum-based and synthetic medium. METHODS: In a randomized masked study, the tissues (n = 64) were preserved in Cornea Max (serum-based) and Cornea Syn (synthetic) series for 36 days at their respective preservation conditions. Following organ culture, corneal tissues (n = 48) were used to prepareDescemet stripping automated endothelial keratoplasty (DSAEK), preloaded ultra-thin (UT) -DSAEK, prestripped Descemet membrane endothelial keratoplasty (DMEK), free-floating DMEK, and preloaded DMEK with endothelium inward and outward grafts. These tissues were preserved for another 4days at room temperature in dextran supplemented media following which they were subjected to trypan blue, alizarin red, live/dead and Zonula Occludens-1 (ZO-1) staining. A separate set of tissues (n = 16) from both the series was used for human corneal endothelial cell (HCEnC) culture. At confluence, the proliferation and cell doubling rate was calculated and the cultured cells were subjected to live/dead, ZO-1, 2A12 and Ki-67 staining. Mann-Whitney test was performed with p < 0.05 deemed statistically significant. RESULTS: After preparation and preservation of the tissues for endothelial keratoplasty, alizarin red showed standard endothelial morphology from both the groups. Endothelial cell loss, hexagonality and uncovered areas did not show statistically significant differences (p > 0.05) between both groups. For HCEnC, cell doubling rate was 4.7 days (p > 0.05). All the antibodies were expressed in both the groups. Hexagonality, polymorphism, cell area, viable/dead cells and Ki-67 positivity were not statistically significant (p > 0.05). CONCLUSIONS: Complete synthetic organ culture series is safe and advantageous for carrying out advanced endothelial keratoplasty graft preparation procedures and for HCEnC culture as it is free from animal or animal-derived products.

The mixture of liquid foam soap, ethanol and citric acid as a new fixative-preservative solution in veterinary anatomy.

The present study investigates the efficiency of liquid foam soap, ethanol, citric acid and benzalkonium chloride as a fixative-preservative solution (a soap-and ethanol-based fixing solution, or SEFS). In this study, ethanol serves as the fixative and preservative, liquid foam soap as the modifying agent, citric acid as the antioxidant and benzalkonium chloride as the disinfectant. The goat cadavers perfused with SEFS (n=8) were evaluated over a period of one year with respect to hardness, colour and odour using objective methods. Colour and hardness were compared between one fresh cadaver and the SEFS-embalmed cadavers. Histological and microbiological examinations were also performed in tissue samples. Additionally, the cadavers were subjectively evaluated after dissection and palpation. The SEFS provided the effectiveness expected over a 1-year embalming period for the animal cadavers. No bacteria or fungi were isolated except for some non-pathogenic Bacillus species. Visible mould was not present on either cadavers or in the surrounding environment. The cadavers maintained an appearance close to their original anatomical appearance, with muscles having good hardness and elasticity for dissection.

Preparation and preservation of hypoxia UW solution.

In order to explore the method to prepare hypoxia UW solution and the stability and preservation of hypoxia UW solution, UW solution was purged by argon or air for 15 min or 60 at a flow rate of 0.8 or 2 L/min, and the oxygen partial pressure of UW solution was detected. The hypoxia UW solution was exposed to the air or sealed up to preserve by using different methods, and the changes of oxygen partial pressure was tested. The results showed that oxygen partial presure of 50 mL UW solution, purged by argon for 15 min at a flow rate of 2 L/min, was declined from 242+/-6 mmHg to 83+/-10 mmHg. After exposure to the air, oxygen partial pressure of hypoxia UW solution was gradually increased to 160+/-7 mmHg at 48 h. After sealed up by the centrifuge tube and plastic bad filled with argon, oxygen partial pressure of hypoxia UW solution was stable, about 88+/-13 mmHg at 72 h. It was concluded that oxygen of UW solution could be purged by argon efficiently. Sealed up by the centrifuge tube and plastic bag filled with argon, oxygen partial pressure of UW solution could be stabilized.

First report of evaluation of K-M media: a new corneal preservation medium.

PURPOSE: To analyze the outcome of keratoplasty performed using Kalevar-Majumdar (K-M) media, a new synthetic viscous medium for preservation of the cornea. MATERIALS AND METHODS: The K-M media-preserved donor eye balls were kept in a bottle in a refrigerator at 4 degrees C till the corneas were used. Forty-eight consecutive keratoplasty cases of pseudophakic bullous keratopathy with vision less than counting fingers at one meter and operated by a single surgeon have been analyzed. Corneal donor button of 7.5 mm was used on the 7.0 mm recipient bed in all cases. Surgery was done with a standard technique. All the cases were examined daily for the first week and at the end of one month for graft clarity, epithelial defect and stromal edema. RESULTS: The K-M media-preserved corneal grafts remained clear at the end of the first week in 95.8% (46 of 48) cases and at the end of one month in 93.7% (45 of 48) cases. Donor epithelial haze cleared in 24 h in all cases. The stromal edema got cleared in the majority (91.7%, 44 of 48) within 24 h. Epithelial defect was seen in only 10.4% (five cases). There was no primary graft failure. CONCLUSION: K-M medium, a new viscous, synthetic corneal preservation medium, is a safe (no primary donor failure) alternative to conventional liquid corneal preservation media. K-M media-preserved eyes appear to have better preserved corneal epithelium with faster achievement of graft clarity postoperatively.

An optimal experimental design for the development of preservative heart solutions.

BACKGROUND: The aim of this study was to determine the optimal composition of a new medium for long-term hypothermic heart preservation. METHODS: The independent effects of 19 compounds were evaluated using an in vitro porcine model. Tissue viability was assessed by measuring the reduction of methyltetrazolium salt, oxygen consumption and energetic compound levels on myocardial biopsies after 24-, 48- or 72-hour incubation periods. Screening of several compounds at two concentrations was performed to greatly reduce the number of experiments. RESULTS: Pyruvate, aspartic acid, chlorpromazine and polyethylene glycol displayed protective properties, whereas calcium (2 mmol/liter), nifedipine, mannitol, magnesium (16 mmol/liter) and reduced glutathione showed deleterious effects. On the basis of these data, the composition of a new preservation solution (Group 1, n = 6) was compared with St Thomas solution (Group II, n = 6) in an isolated, 24-hour pig heart preservation model. During reperfusion, left ventricular developed pressure and coronary blood flow were significantly higher (p <.01) in Group I, suggesting better preservation. CONCLUSIONS: Our technique allows for rapid and efficient screening of many compounds currently used in the composition of preservation solutions for cardiac surgery.