N. A. Filippova

Regenerative endodontics is a strategy aimed at the regeneration of dental pulp or at least the formation of pulp-like tissue, ideally the pulp-dentin complex; regeneration of damaged coronal dentin, resorbed root, cervical or apical dentin. Regenerative endodontic strategies include stem cell transplantation and regenerative endodontic procedures (REP). REP methods are currently used in the endodontic treatment of open-apice teeth in patients aged 7–10 years. The most likely outcome of this treatment is repair (“maturation”) of the root, rather than regeneration of its tissues. Aim of the study : to develop the method and evaluate the efficacy of dental pulp stem cells in combination with fibrin gel for regenerative endodontic treatment of mature permanent teeth in a large animal model. Materials and methods . The study was conducted on minipigs. While under general anesthesia (xylazine and tiletamine-zolazepam), the animals underwent an X-ray examination of their oral cavities. This examination was performed to select a tooth that most closely resembled a human tooth in terms of its position in the jaw arch, as well as the number and shape of its roots and canals. The first left two-rooted molar (P2) was selected. The crown pulp was amputated, and the root pulp was extirpated. The canals were then filled with fibrin gel containing allogeneic pig dental stem cells. The gel was mixed with fibrinogen polymerization catalysts ( thrombin and calcium chloride) immediately before being injected into the canals for polymerization. Thus, the gel (3 μL, containing 15,000–18,000 cells per canal) took the shape of the canal during polymerization. Next, the gel was isolated with mineral trioxide aggregate, and the crown was filled with chemically cured, reinforced, packable glass ionomer cement. Four months after the endodontic treatment, the tooth was removed, fixed, decalcified, and used for a standard histological examination. Stepwise serial sections, 3–5 μm thick, were prepared and stained with hematoxylin and eosin. For quantitative assessment, seven sections were selected at different levels with a step of 10 μm, the images were scanned, and morphometric calculations were performed. Absolute and relative values of lengths and areas were assessed, as well as the degree of vascularization. Results . The length, shape and volume of the root canals of the first left premolar (P2) are similar to those in humans, which allowed us to use approaches and equipment developed for the endodontic treatment of human teeth, thus increasing the relevance of the model. Histological sections in the apical part of the canal showed the formation of vascularized pulp-like stromal tissue, and in the middle and apical thirds of the root, areas with a palisade layer of cylindrical cells — active odontoblasts producing dentin — were detected next to basophilic masses. There were no inflammatory processes in the periapical area of the endodontically treated tooth. No changes in the animals’ well-being or eating behavior were observed. Conclusion . The results of the pilot study indicate the prospects for the development of regenerative endodontics methods for the treatment of mature permanent teeth with formed roots. Scaffolds based on fibrin gel and dental pulp stem cells are generally suitable for the purposes of regenerative endodontics, but the method needs to be further improved to form pulp architectonics.

The article addresses improving the methodology for distributing the annual volume of unobserved agricultural production in Russia by month.The study used methods for calculating averages and variances, dispersion analysis and the index method.The study aims to explain the algorithm for distributing the annual volume of agricultural production by month to improve the quality of official statistical information. The authors analyzed existing approaches to the distribution of agricultural output, reviewed the experience of other countries in the subject area of the study, and formulated methodological recommendations for distributing the volume estimates of the output of unobserved types of agricultural production by month.Official statistical methodology, published results of scientific research by Russian and foreign scientists, current regulatory legal acts of the Russian Federation and other countries in the subject area, and agricultural calendars for the period under review served as a theoretical foundation for this work.The scientific novelty of the conducted study lies in developing scientific and methodological recommendations for the distribution of agricultural production volumes in actual prices by month to improve the objectivity of official statistics. The relevance of the study stems from the need to refine the existing approaches to the distribution of the annual volume of agricultural production.

Laboratory predatory mammals (dogs, cats and ferrets) are animals that make valuable contributions to biomedical research as test systems in drug trials, despite the tendency to exclude highly sophisticated animals from experimentation. However, there are experiments in which researchers cannot yet abandon predatory mammals for a number of reasons. Their size plays an important role here; the animals are relatively large. In addition, a number of diseases that are modeled only on these animals, due to the receipt of more accurate models that are very similar to the processes occurring in humans. Health monitoring of laboratory animals, aimed at monitoring the condition of animals and maintaining their well-being, should be relevant for testing centers. The use of one provided list of pathogens for monitoring the health of animals in different territories remote from each other, in which there may be different epidemiological situations, different means of preventing infectious diseases, vaccines, etc., may be used, but it seems doubtful. In search of an up-to-date list of pathogens for control in laboratory predatory mammals in Russia, a risk assessment system was used, in particular the FMEA / FMECA method (Failure Mode Effect Analysis/Failure Mode Effect Criticality Analysis) — Analysis of the types and consequences of potential non-conformities. We used this method to evaluate the list of pathogens for laboratory primates, miniature pigs and rabbits. The risk assessment made it possible to identify some indicators from the international list of pathogens that are not relevant for the regions of the Russian Federation, as well as to detect several indicators that pose a danger to laboratory animals used in Russia, but are not included in the FELASA list, which should be taken into account when conducting health monitoring.