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Purpose: Mouse spermatozoa for archiving laboratory mice or for in vitro fertilization (IVF) are routinely obtained from the cauda epididymis of adult males sacrificed for this purpose. To avoid the death of the donor, we tested whether a precisely timed interruption of the mating act could be used for repeated sperm collection from laboratory mice., Methods: Sperm donors (B6D2F1) were mated with a receptive female, and mating behavior was observed. The stud was separated from the female 1-2 s after the onset of the ejaculatory shudder. The ejected copulatory plug with the yellowish viscous ejaculate was carefully removed from the penile cup., Results: A total of 80 ejaculates were successfully obtained from 100 ejaculations. The latency to first mount was 1.1 ± 1.1 min (mean ± SD) and to ejaculation 8.1 ± 4.7 min. The average number of mounts to ejaculation was 10.5 ± 5.8, and the mean number of spermatozoa per collected ejaculate was 1.86 ± 1.05 × 10 6 . An average fertilization rate of 76% was observed after IVF., Conclusions: Separating the stud from the female just before ejaculation is feasible, easy to learn, and requires no special equipment. The sperm count of collected ejaculates is lower than natural ejaculations, but higher than previous in vivo sperm collection methods achieved. We recommend this simple sperm collection method in mice, especially when the donor cannot be sacrificed and/or repeated sperm collection from the same animal is required for experimental purposes., (© 2024. The Author(s).)

Purpose: Transplantation of ovarian tissue is a valuable method to rescue mouse strains with fertility problems and to revitalize archived strains. The purpose of this study was to investigate the effect of (i) different sizes of transplanted ovary pieces on reproductive outcome, (ii) use of immunodeficient recipients to overcome the limitation of histocompatibility, and (iii) to compare different protocols for cryopreservation of ovarian tissue., Methods: Halves, quarters, and eights of mouse ovaries were transplanted. Half ovaries from B6 donors were transferred into immunodeficient mice. Halves of ovaries were frozen according to four different protocols, thawed and transferred., Results: Pregnancy rate after transplantation of ovarian tissue was high (90-100%) independent of the transplant size. Although, the average litter size was significantly lower for recipients of quarters and eights (4.4 and 4.6 vs. 6.5), the total number of offspring produced per donor ovary was higher compared with recipients of halves. Pregnancy rate of immunodeficient recipients was 40% (mean 4.7 offspring per litter). All four cryopreservation protocols used were able to preserve functionality of the ovarian tissue., Conclusions: Transplantation of ovarian tissue smaller than halves resulted in reduced litter sizes. The distribution of ovarian tissue of one donor female to 4 or 8 recipients will therefore yield in a higher total number of offspring in a certain time period. The use of immunodeficient recipients is an option for non-histocompatible donors. Cryopreservation of ovarian tissue is generally feasible but the function of frozen-thawed ovary halves after transplantation differs depending on the freezing protocol used.

In 2008 the Ludwig Boltzmann Cluster Oncology (LBC ONC) was established on the basis of two previous Ludwig Boltzmann Institutes working in the field of hematology and cancer research. The general aim of the LBC ONC is to improve treatment of hematopoietic neoplasms by eradicating cancer-initiating and disease-propagating cells, also known as leukemic stem cells (LSC) in the context of leukemia. In a first phase, the LBC ONC characterized the phenotype and molecular aberration profiles of LSC in various malignancies. The LSC phenotypes were established in acute and chronic myeloid leukemia, in acute lymphoblastic leukemia and in chronic lymphocytic leukemia. In addition, the concept of preleukemic (premalignant) neoplastic stem cells (pre-L-NSC) was coined by the LBC ONC and was tested in myelodysplastic syndromes and myeloproliferative neoplasms. Phenotypic characterization of LSC provided a solid basis for their purification and for the characterization of specific target expression profiles. In a second phase, molecular markers and targets were validated. This second phase is ongoing and should result in the development of new diagnostics parameters and novel, more effective, LSC-eradicating, treatment strategies; however, many issues still remain to be solved, such as sub-clonal evolution, LSC niche interactions, immunologic control of LSC, and LSC resistance. In the forthcoming years, the LBC ONC will concentrate on developing LSC-eradicating strategies, with special focus on LSC resistance, precision medicine and translation of LSC-eradicating concepts into clinical application.

Synapse-associated protein 1 (Syap1/BSTA) is the mammalian homologue of Sap47 (synapse-associated protein of 47 kDa) in Drosophila. Sap47 null mutant larvae show reduced short-term synaptic plasticity and a defect in associative behavioral plasticity. In cultured adipocytes, Syap1 functions as part of a complex that phosphorylates protein kinase Bα/Akt1 (Akt1) at Ser(473) and promotes differentiation. The role of Syap1 in the vertebrate nervous system is unknown. Here, we generated a Syap1 knock-out mouse and show that lack of Syap1 is compatible with viability and fertility. Adult knock-out mice show no overt defects in brain morphology. In wild-type brain, Syap1 is found widely distributed in synaptic neuropil, notably in regions rich in glutamatergic synapses, but also in perinuclear structures associated with the Golgi apparatus of specific groups of neuronal cell bodies. In cultured motoneurons, Syap1 is located in axons and growth cones and is enriched in a perinuclear region partially overlapping with Golgi markers. We studied in detail the influence of Syap1 knockdown and knockout on structure and development of these cells. Importantly, Syap1 knockout does not affect motoneuron survival or axon growth. Unexpectedly, neither knockdown nor knockout of Syap1 in cultured motoneurons is associated with reduced Ser(473) or Thr(308) phosphorylation of Akt. Our findings demonstrate a widespread expression of Syap1 in the mouse central nervous system with regionally specific distribution patterns as illustrated in particular for olfactory bulb, hippocampus, and cerebellum., Competing Interests: The authors have no conflicts of interest to declare.

Background: Mesh tearoff from the tissue is the most common reason for hernia recurrence after hernia surgery involving the use of a synthetic mesh. Various fixation systems were critically compared in terms of their retention strength and the formation of adhesions., Methods: In a prospective study with 25 Sprague-Dawley rats, two pieces of Parietex composite meshes measuring 2 x 3 cm were fixed intraperitoneally in a paramedian location. The randomized mesh fixation groups included transfascial fixed suture, ProTack, AbsorbaTack, and I-Clip. Of the 25 rats, 12 were killed and analyzed 1 week after implantation, with the remaining 13 rats killed and analyzed after 2 months. Adhesions observed at the time of mesh removal were measured according to an adhesion scoring system, and the fixation strengths of the individual fixation systems were tested. Additionally, the foreign body reaction to the mesh and fixation systems was measured as well as their potential degradation., Results: After 1 week, the retention strength of transfascial fixed suture was significantly higher (8.7 N/cm(2)) than that of ProTack (5.6 N/cm(2)) or AbsorbaTack (5.7 N/cm(2)). After 2 months, the retention strength had increased to 13.2 N/cm(2) in the transfascial fixed suture group, which was significantly higher than in the ProTack (9.7 N/cm(2)) or AbsorbaTack (8.7 N/cm(2)) groups. In contrast, the mesh could be fixed with the I-Clip only in 56% of the cases, and then achieved rather poor retention strength. Adhesion was significantly greater in the ProTack group than in any of the other groups (p < 0.001). At 2 months, scanning electron microscopy showed only marginal degradation of the absorbable elements., Conclusions: Suture fixation led to satisfactory attachment of the prosthesis. Additional widespread anchorage of the mesh was achieved with ProTack or AbsorbaTack. The feasibility and retention strength of the I-Clip were poor.

Background: The number of mesh-based therapies of inguinal hernias is increasing compared with the classical suture techniques such as Shouldice and Bassini. Many different types of meshes with regard to material, pore size and surface coating are available. A recently offered mesh (Parietene Progrip) combines the properties of a standard lightweight polypropylene mesh with a whole surface fixation by incorporation of micro hooks. Therefore, additional fixation elements such as screws, tacks or clips become redundant when using this material. However, in treated male patients the micro hooks will also come into contact with the ductus deferens. As the sensitivity of this structure is known, the question arises of whether this new self-gripping mesh might damage susceptible tissue layers and impair male fertility., Methods: Two different meshes, a standard lightweight polypropylene mesh (Parietene-Light) and a new self-gripping polypropylene mesh (Parietene Progrip) with absorbable micro hooks were wrapped surgically around the prepared ductus deferens of each of ten Sprague-Dawley rats. In five control rats ducts were only separated bluntly from adherent tissue. After 2 months rats were sacrificed and implants were recovered together with the ductus deferens for histology and electron microscopy., Results: Samples from all animals showed an unrestricted lumen of the ductus deferens. Only minor inflammatory reactions with some infiltrating cells could be observed. Giant cells were present around the mesh fibres. Scanning electron microscopy revealed no degradation of the material surface after 2 months of implantation., Conclusion: The new self-gripping mesh showed no harmful influence on the ductus deferens in the rat model. Considering the larger dimensions of the ductus deferens in humans any detrimental effect on the exposed tissue can be excluded. The surface of the fibres was not subjected to material degradation.

Formation and maintenance of a neuronal network is based on a balance between plasticity and stability of synaptic connections. Several molecules have been found to regulate the maintenance of excitatory synapses but nothing is known about the molecular mechanisms involved in synaptic stabilization versus disassembly at inhibitory synapses. Here, we demonstrate that Nogo-A, which is well known to be present in myelin and inhibit growth in the adult CNS, is present in inhibitory presynaptic terminals in cerebellar Purkinje cells at the time of Purkinje cell-Deep Cerebellar Nuclei (DCN) inhibitory synapse formation and is then downregulated during synapse maturation. We addressed the role of neuronal Nogo-A in synapse maturation by generating several mouse lines overexpressing Nogo-A, starting at postnatal ages and throughout adult life, specifically in cerebellar Purkinje cells and their terminals. The overexpression of Nogo-A induced a progressive disassembly, retraction and loss of the inhibitory Purkinje cell terminals. This led to deficits in motor learning and coordination in the transgenic mice. Prior to synapse disassembly, the overexpression of neuronal Nogo-A led to the downregulation of the synaptic scaffold proteins spectrin, spectrin-E and beta-catenin in the postsynaptic neurons. Our data suggest that neuronal Nogo-A might play a role in the maintenance of inhibitory synapses by modulating the expression of synaptic anchoring molecules.

Transgenic animal models for neurocarcinogenesis have provided significant insights into the molecular mechanisms underlying carcinogenic processes, including those which affect the nervous system. In view of the very rapid pace of acquisition of knowledge, it is not possible to cover all transgenic mouse models for neural tumors. Instead, this article discusses some of the most important technical innovations for manipulation of the mammalian genome (notably the various methods for targeted genome modifications, as well as the technology for introducing large DNA fragments into the germ line of mice), and presents a selection of the transgenic mouse models which are proving most promising for furthering our understanding of the pathogenetic basis of cancer in the nervous system.