To study the function and maturation of the human hematopoietic and immune system without endangering individuals, translational human-like animal models are needed. We compare the efficiency of CD34+ stem cells isolated from cryopreserved cord blood from a blood bank (CCB) and fresh cord blood (FCB) in generating highly engrafted humanized mice in NOD-SCID IL2Rγnull (NSG) rodents. Interestingly, the isolation of CD34+ cells from CCB results in a lower yield and purity compared to FCB. The purity of CD34+ isolation from CCB decreases with an increasing number of mononuclear cells that is not evident in FCB. Despite the lower yield and purity of CD34+ stem cell isolation from CCB compared to FCB, the overall reconstitution with human immune cells (CD45) and the differentiation of its subpopulations e.g., B cells, T cells or monocytes is comparable between both sources. In addition, independent of the cord blood origin, human B cells are able to produce high amounts of human IgM antibodies and human T cells are able to proliferate after stimulation with anti-CD3 antibodies. Nevertheless, T cells generated from FCB showed increased response to restimulation with anti-CD3. Our study reveals that the application of CCB samples for the engraftment of humanized mice does not result in less engraftment or a loss of differentiation and function of its subpopulations. Therefore, CCB is a reasonable alternative to FCB and allows the selection of specific genotypes (or any other criteria), which allows scientists to be independent from the daily changing birth rate.

Despite sepsis being a life-threatening disease, targeted drugs that improve the therapy of affected patients are still lacking. Infants and adults differ in the maturity level of their immune system and this results in distinct reactions to Gram-negative bacteria. To study reactions of human immune cells in vivo, we used NOD scid gamma mice transplanted with human CD34 stem cells to engraft a functional human immune system. Human cells undergo differentiation and maturation in these mice after transplantation and, accordingly, animals were divided into two groups: 8-13 wk and 15-22 wk after transplantation. Endotoxemia was induced by injecting LPS. Six h later, mice were euthanized. In both groups, LPS stimulation induced a decrease of CD14 monocytes in peripheral blood, an up-regulation of activation markers on different cell subsets such as myeloid dendritic cells, and a release of the human cytokines TNF-α, IL-6 and IL-10. However, significant differences were detected with regard to the amounts of released cytokines, and 8-13-wk-old mice produced more IL-6, while PTX3 was mainly released by 15-22-wk-old animals. Thus, here we provide a potential model for preclinical research of sepsis in infants and adults.

The aim of this study was to investigate the usefulness of new software Pixel Flux (PXFX) for clinical evaluation of tissue perfusion in the field of reproduction in dogs. The experiment was performed on six adult Beagle dogs. Different organs and tissues of the animals were examined with the MyLab25 Gold ultrasound system. Blood flow in the ovary, testicle, prostate, the ramification of the penile artery, and the network of blood vessels of the pampiniform plexus were examined with the use of colour coded Doppler technique, and obtained data was evaluated with the PXFX software. The more objective digital evaluation of data obtained with colour Doppler sonography through the application of dynamic tissue perfusion measurements provides new opportunities for diagnosis, as well as continuous monitoring of the function of the examined tissues and organs. The use of PXFX software is strongly indicated as a tool in small animal practice as an additional method for evaluation of tissue perfusion, especially in the cases when other methods like pulsed wave Doppler techniques are difficult to be performed.

Spatial angle-corrected global fetal perfusion measurement improves existing approaches to fetal perfusion evaluation, and is feasible, simple and fast. Thus, it can be recommended to explore the relationship of fetal perfusion and disturbances of fetal development.

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