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Intestinal T‐cell lymphomas are common in dogs, but histopathological diagnosis remains challenging because of accompanying enteritis with lymphocyte involvement. Invasively taken full‐layer biopsies are still required for reliable differentiation. The detection of specific microRNA expression patterns in canine intestinal T‐cell lymphoma could provide new possibilities to differ intestinal lymphoma from benign inflammation and could lead to further understanding of lymphomagenesis. The objective of this study was to characterize microRNA expression in distinct groups of formalin‐fixed and paraffin‐embedded samples from canine intestinal T‐cell lymphomas, lymphoplasmacellular enteritis and healthy intestinal tissue. In a preliminary test with two samples per group, total RNA was extracted (RNEasy FFPE Kit, Qiagen), reverse transcribed (miScript II RT Kit, Qiagen) and pre‐amplified (miScript PreAmp PCR Kit, Qiagen). We performed comparative quantitative PCR on microRNA PCR Array plates (Qiagen) with pre‐fabricated reactions for 183 different mature canine microRNAs. Subsequently, 12 microRNAs with conspicuous expression changes in the lymphoma group were selected and microRNA expression of all samples (n = 8) per group was analysed with individual microRNA assays (miScript Primer Assays, Qiagen) on the reverse transcribed RNA without pre‐amplification. Our results revealed lymphoma‐specific expression patterns, with down‐regulation of the tumour‐suppressing microRNAs miR‐194, miR‐192, miR‐141 and miR‐203, and up‐regulation of oncogenic microRNAs, including microRNAs from the miR‐106a~363 cluster. In addition, we detected only slight expression alterations between healthy intestinal tissue and lymphoplasmacellular enteritis cases. We conclude that microRNA expression patterns can be used to separate T‐cell lymphomas from healthy tissue and benign inflammatory disorders. [ABSTRACT FROM AUTHOR]

Safety testing is one major part of the licensing procedure for veterinary vaccines and demands a large number of animals. Magnetic resonance imaging (MRI) was tested as an alternative, which may lead to a reduction in numbers of animals required for safety testing, and, correspondingly to a detailed description of the three-dimensional extent of the local tissue reaction repetitively in live pigs. In previous pig studies the following questions arose: (1) Can MRI be used in suckling pigs in terms of safety testing? (2) Does the injection of 2 ml saline solution lead to a volume effect resulting in tissue alterations comparable to a vaccine response? (3) Is the local reaction size affected by the tattoo marking of the injection point for the final pathomorphologic examination? To answer these questions the following study was performed by comparing two vaccine groups of suckling piglets (8 animals per group; A and B) with two control groups (4 animals per group; C and D). One control group was injected with a saline solution (C) and the other was only tattoo marked (D). The animals were examined using MRI at days 1, 8, 15, 22, 29, 36, and 43 post vaccination, ending with a final pathomorphologic examination. Pathomorphologic examination confirmed MRI findings. Saline solution does not result in a local tissue reaction as detected after injecting vaccines. Tattoo marking causes no local tissue reaction, neither in MRI nor in pathomorphologic examination. Therefore, MRI can be used as an alternative method for safety testing of vaccines in pigs of different age categories offering repetitive measurements of local tissue reactions. Involved cells might be examined only in a final pathomorphologic examination at the end of the trial on a reduced number of animals. [ABSTRACT FROM AUTHOR]