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Fresh autologous vein grafts are commonly used for infrainguinal vascular reconstructions with good results. Previously we have confirmed the high viability index of homografts even after long-term storage at 4°C in tissue culture medium. In this clinical study, we have evaluated the in vivo efficiency of this storage method in humans with major peripheral graft infections. Between April 2006 and November 2008, data from patients who underwent graft excision and venous allograft reconstruction were collected prospectively (5 men, 2 women, mean age 68 years). Six patients had acute ischemia at the time of allograft reconstruction, while 3 had experienced anastomosis rupture. Allograft reconstruction was performed as an emergency procedure in 3 cases. The observed parameters included patient survival, limb salvage, persistence or recurrence of infection and allograft patency. In the follow-up period reoperation, excision or thrombectomy was necessary in 3 cases. There were no perioperative deaths, early amputations, persistent or recurrent infections. In conclusion, this study demonstrates the efficacy of long-term 4°C storage of venous allografts for revascularization in cases with peripheral bypass graft infection. We suggest that this technique is a useful option for graft preservation and propose a wide-scale introduction. Copyright © 2009 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Objective: The color density of the methyl tetrazolium (MTT) test is proportional to mitochondrial enzyme activity thus reflecting cellular viability. The aim was to evaluate the MTT test as a viability assay for vein homograft studies. Materials and Methods: Fresh intact vein samples were harvested during multi-organ procurement. The reliability of the MTT assay was tested by a fluorescent dye combination (1 μg/ml propidium iodide PI and 4 μM/ml SYTO-16 stains). The enzyme kinetics of the reaction was also investigated. The optimal reagent concentration, biopsy size and incubation period were established. Results: There was a linear relationship between the vein homograft’s weight and the pigment production activity. A nonspecific reaction (8.6%) was observed in negative controls. The MTT cleavage up to 0.1% (w/v) follows the Michaelis kinetics. The Michaelis constant (2,805 ± 130 μM), the maximal velocity (196 ± 2.2 × 10–5 μM s–1) and the velocity constant (6.98 ± 0.2 × 10–7 s–1) was calculated. The viability assessed by fluorescent dyes simultaneously visualized the live/dead cell ratio, which can be calculated by image analysis software. Conclusion: The use of MTT in colorimetric assays offers high sensitivity. The assay is simple, inexpensive, and reproducible in vein homograft studies. Copyright © 2004 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]