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The currently available methods for conservation of biobank material are mainly based on formalin fixation or the use of different freezing techniques. For molecular biological analysis, it is common to use quick freezing and low-temperature storage of the tissue materiel. This is a very energy-intensive and expensive method that requires advanced infrastructure, including monitoring and control procedures. The purpose of this work has been to study drying as an alternative process to cryogenic storage of undried biobank material, especially for use in cancer research groups. Fast freezing has been shown to be suitable to preserve the integrity of RNAs, while traditional formalin fixation preserves proteins and thus morphology in a good way. Various fresh-harvested murine tissues, such as lung, heart, skeletal muscle, liver, and kidney, were quickly frozen in liquid nitrogen and then subsequently dried at +5°C and −10°C, respectively, in a heat pump dryer. After drying, the RNA integrity was measured. The...

Ischaemic preconditioning may protect the intestine from subsequent prolonged ischaemia. This study evaluates whether a much longer initial ischaemia, encountered clinically, may modify intestinal resistance to further ischaemia in a pig model.After cross-clamping of the superior mesenteric artery for 1 h, the intestine was either reperfused for 8 h or a second cross-clamping for 1 h was performed at 4 h of reperfusion. Based on microarray analysis of intestinal samples at 1, 4 and 8 h of reperfusion, mRNA of selected genes was measured with QRT-PCR.The first ischaemic period caused exfoliation of surface epithelial cells from the basement membrane comprising about 90 % of the villi tips, a marked increase in permeability and depletion of ATP. The second ischaemic challenge caused about 30 % less denudation of the basement membrane (p = 0.008), no increase in permeability (p = 0.008) and less depletion of ATP (p = 0.039). mRNAs for superoxide dismutase 2, heat shock proteins and signal transducer and activator of transcription 3, which may protect against ischaemia/reperfusion injury, were up-regulated throughout the reperfusion period. mRNAs for matrix metalloproteinase 1, connexin 43 and peripheral myelin 22, which may be associated with cell migration or tight junctions, showed a particular up-regulation at 4 h of reperfusion.One hour of initial ischaemia followed by 4 h of reperfusion is associated with increased intestinal resistance to further ischaemia. The differential regulation of genes identified in this study provides working hypotheses for mechanisms behind this observation.