Page 255 - Prevention and Treatment of Incisional Hernia- New Techniques and Materials

In ammatory response in a contaminated environment
Analyses
Stained sections were analysed by light microscopy (Olympus, Tokyo, Japan). Per staining, sections were blinded and the number of cells in 5 areas at the interface of the mesh and tissue was ranked. In the case of the control group, cells were counted subcutaneously, at the place where in the other groups the mesh was implanted. Samples were ranked based on the number of positive cells, ranks were ranging from 1 to 58 (due to a total of 58 analysed samples). Control group day 28: 8 samples, day 90: 7 samples. Parietene® 8 and 5 samples respectively, Parietene Composite® 5 and 4 samples, C-Qur® day 28: 5 samples, Sepramesh® day 90: 4 samples, Dualmesh® day 28: 3 samples, day 90: 4 samples, Omyramesh® day 28: 5 samples. Ranking was performed by two independent observers (NG and NK). The ranking of one observer was compared with the ranking of the other observer. If there was a di erence in ranking per sample of more than 15, the samples were analysed again. After that, the mean ranking per sample was calculated from the ranking of one observer and the other observer. Then the samples were unblinded and were used for further analysis. The number of iNOS-positive cells was divided by the number of CD206- positive cells leading to an M1/M2 ratio. The natural logarithm of this ratio was calculated for visualisation. Data is presented as box plots with medians and whiskers showing the interquartile range.
Statistics
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The medians of the groups were compared with a Kruskal-Wallis test (independent samples median test) and Mann-Whitney in SPSS (IBM Corp. Released 2011. IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp.) False Discovery Rate was used for mathematical correction by multiple comparisons. p<0.05 was considered statistically signi cant.
Results
The number of mast cells and T-cells were analysed in the tissue adjacent to the meshes, since these two cells are the main attractors of macrophages. We found no signi cant di erences in the numbers of mast cells between the biomaterials or compared to the control group (Figure 1a).
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