Altered cellular membrane fluidity levels and lipid peroxidation during experimental pancreas transplantation

Although the pathogenesis of ischemia reperfusion (IR) injury is based on complex mechanisms, free radicals play a central role. We evaluated membrane fluidity and lipid peroxidation during pancreas transplantation (PT) performed in 12 pigs (six donors and six recipients). Fluidity was measured by fluorescence spectroscopy, and malondialdehyde (MDA) and 4-hydroxyalkenals (4-HDA) concentrations were used as an index of lipid oxidation. Pancreatic tissues were collected as follows: (A) donor, immediately before vascular clamping; (B) graft, following perfusion lavage with University of Wisconsin preservation fluid; (C) graft, after 16 h of cold ischemia; and (D) recipient, 30 min vascular postreperfusion. Fluidity and MDA and 4-HDA concentrations were similar in cases A, B, and C. However, there was significant membrane rigidity and increased lipid peroxidation after reperfusion (D). These findings suggest that reperfusion exaggerates oxidative damage and may account for the rigidity in the membranes of allografts during PT.

[Allergic mediators in tear from children with seasonal and perennial allergic conjunctivitis]

PURPOSE

To evaluate the concentration of allergic mediators in tears of children with seasonal allergic conjunctivitis (SAC) and perennial allergic conjunctivitis (PAC) compared with controls.

METHODS

Twenty children with allergic conjunctivitis (17 SAC, and 3 PAC) and sixteen healthy children were included in this study. Tear samples were collected using a Merocel sponge (Oasis, 0525), and immediately eluted by incubation in elution buffer and subsequent centrifugation at 20,000 rpm for 30 min at 4°C. Concentrations of histamine (HIS), tryptase (TPS), eosinophil chemotactic factor (ECF), major basic protein (MBP), eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN), IgE and E-selectin were measured using enzyme linked immunosorbent assays (ELISA). Data were compared with the Mann-Whitney U test (P<.05), and multivariate analyses were also performed.

RESULTS

Tear levels of TPS (P=.014), MBP (P=.032), ECP (P=.0041), IgE (P=.014) and EDN (P=.00077) showed significant differences in children with SAC and PAC compared to controls.

CONCLUSION

The simultaneous analyses of allergic mediators in the tears of children with SAC and PAC showed a significant elevated concentration in EDN, ECP and MBP in allergic group and decreased levels in IgE and TPS. Statistical analyses showed a diagnostic accuracy of 94.4% using the eight molecules panel.