Periprosthetic osteolysis is a major cause of aseptic loosening in joint arthroplasty. This study investigates the impact of CT (calcitonin) deficiency and CT substitution under in-vivo circumstances on particle-induced osteolysis in Calca -/- mice.

Laboratory animal facility managers must ensure that animal experiments can be carried out under optimal scientific conditions, that all legal requirements are met, and that animal welfare is maximized. Animal experimentation is stressful not only for the animals involved but also for the people who maintain these animals or carry out the experiments. Many of those involved find themselves in a constant conflict between scientific necessity, care, and harm. Under the term Culture of Care, procedures have been developed to reduce the burden of animal experimentation on the animals and the staff involved. The focus here is on what laboratory animal facility managers can do to improve the welfare of laboratory animals and the people working with them. Exemplary measures are the improvement of the housing conditions of laboratory animals, the introduction of uniform handling measures, clear and transparent structures via a quality management system, implementation of a no-blame culture of error (e.g., via Critical Incident Reporting System in Laboratory Animal Science [CIRS-LAS]), and open and respectful communication with all parties involved in animal experimentation, including the public and representatives of the authorities (public webpage, open house policy). The 6 Rs must be considered at all times: replacement, reduction, refinement, respect, responsibility, and reproducibility. We are writing this article from the perspective of laboratory animal facility managers in Germany.

A new life starts with successful fertilization whereby one sperm from a pool of millions fertilizes the oocyte. Sperm motility is one key factor for this selection process, which depends on a coordinated flagellar movement. The flagellar beat cycle is regulated by Ca²⁺ entry via CatSper, cAMP, Mg²⁺, ADP and ATP. This study characterizes the effects of these parameters for 4D sperm motility, especially for flagellar movement and the conserved clockwise (CW) path chirality of murine sperm. Therefore, we use detergent-extracted mouse sperm and digital holographic microscopy (DHM) to show that a balanced ratio of ATP to Mg²⁺ in addition with 18 µM cAMP and 1 mM ADP is necessary for controlled flagellar movement, induction of rolling along the long axis and CW path chirality. Rolling along the sperm’s long axis, a proposed mechanism for sperm selection, is absent in sea urchin sperm, lacking flagellar fibrous sheath (FS) and outer-dense fibers (ODFs). In sperm lacking CABYR, a Ca²⁺-binding tyrosine-phosphorylation regulated protein located in the FS, the swim path chirality is preserved. We conclude that specific concentrations of ATP, ADP, cAMP and Mg²⁺ as well as a functional CABYR play an important role for sperm motility especially for path chirality.

The tracheal system of scutigeromorph centipedes (Chilopoda) is special, as it consists of dorsally arranged unpaired spiracles. In this study, we investigate the tracheal systems of five different scutigeromorph species. They are strikingly similar to each other but depict unique characters compared to the tracheal systems of pleurostigmophoran centipedes, which has engendered an ongoing debate over a single versus independent origin of tracheal systems in Chilopoda. Up to now, only the respiratory system of Scutigera coleoptrata was investigated intensively using LM-, TEM-, and SEM-techniques. We supplement this with data for species from all three families of Scutigeromorpha. These reveal interspecific differences in atrial width and the shape and branching pattern of the tracheal tubules. Further, we investigated the tracheal system of Scutigera coleoptrata with three additional techniques: light sheet microscopy, microCT and synchrotron radiation based microCT analysis. This set of techniques allows a comparison between fresh versus fixed and dried material. The question of a unique vs. multiple origin of tracheal systems in centipedes and in Myriapoda as a whole is discussed with regard to their structural similarities and differences and the presence of hemocyanin as an oxygen carrier. We used morphological and molecular data and the fossil record to evaluate the alternative hypotheses.