Comorbidities in patients with revision hip arthroplasty

Background. According to the existing concept of risk factors, the outcome of hip arthroplasty (HA) is affected not only by the quality of the prosthetic work, but also by the presence of one or more concomitant diseases. Purpose of the study - to perform a frequency analysis of co-morbidities in patients who underwent revidion HA, depending on the timing of its conduct. Materials and methods. On the basis of the endoprosthesis clinic at the Novosibirsk Research Institute of Traumatology and Orthopedics, a continuous sample of data was performed from medical records of patients (n = 667), who underwent revision HA in the period of 2013-2015. Primary HA was performed in various medical institutions in Russia and abroad in the period of 1992-2015. The cases of revision Ha were divided according to the terms of their implementation: postoperative (up to 2 months, n = 11), early remote (more than 2 months but less than 5years after HA, n = 371) and late remote (more than 5 years, n = 285). Variable coding and matrix creation, frequency analysis, average and relative risk (RR) calculation were performed. Results. The RR of postoperative and early revision intervention after HA is calculated depending on the presence of concomitant diseases. As a reference group, cases of late revision HA are taken. Calculation of the RR showed that the presence of concomitant diseases increases the risk of failure of the endoprosthesis in the postoperative period (in diabetes mellitus type 2 - 4.3 times, with excessive body weight and obesity - 2.0, with diseases of the nervous system - 3.9, liver - 2.8, veins of the lower extremities - in 2.9 and with chronic anemia - 3.7 times). The risk of undergoing revision HA in the early remote period is 1.7 times higher in the presence of concomitant malignant neoplasm than in the late remote period (p < 0.1). RR decreases with ischemic heart disease, chronic pyelonephritis, cholelithiasis and other pathology of the musculoskeletal system, i.e., revision interventions are performed in these patients much later. Conclusions. When analyzing the concomitant pathology, significant differences in the incidence of chronic diseases were found depending on the timing of the revision HA. Chronic diseases, which are risk factors for early failure of the endoprosthesis, have been identified. In cases when the risk of complications is high due to comorbidity it is more appropriate to refuse from the operation altogether

Effect of Preheating on Mechanical Properties of Different Commercially Available Dental Resin Composites

Background: This study aimed to reveal the effect of preheating on the surface microhardness and shear strength of composite materials used in the restoration of posterior teeth. Methods and Results: There were 3 composite materials under the study: Estelite Posterior, Harmonize and Filtek Z550. To make static and dynamic tests of them, 120 filling samples were prepared. Of those, 60 samples were for surface hardness measurements and 60 samples were used to evaluate the shear strength of composite materials. We formed 12 study groups with 10 filling samples in each. Samples made off Estelite Posterior, Harmonize™, and Filtek™ were designated with E, H, and F capital letters, respectively; the "VH" abbreviation indicated static Vickers hardness testing and "SS" was assigned for dynamic shear testing; mark (°) was used when preheating was applied. Filling samples were made of heated (up to 60°C) and room-temperature (23-25°C) composite materials. The filling samples of EVH, EºVH, HVH, HºVH, FVH, and FºVH groups were subjected to a surface microhardness test. The samples of ESS, EºSS, HSS, HºSS, FSS, and FºSS groups were subjected to shear-strength assessment of materials. The surface microhardness of filling samples was measured using a ПMT-3 Vickers hardness tester and the Vickers hardness number (VHN) was calculated. Dynamic tests were carried out using an UltraTester machine (Ultradent, Inc., USA) and shear test method until the shear-strength (SS) filling sample had completely failed. After analysis of the obtained results, it was found that preheating had enhanced the surface hardness and mechanical strength of the composite materials used in the study. However, the positive influence of preheating was significant only in the EVH-EºVH, ESS-EºSS, HSS-HºSS, and FSS-FºSS groups in 1.21, 1.09, 1.33, and 1.16 times, respectively. In the HVH-HºVH and FVH-FºVH groups, the identified differences were not of significance despite the improvement in mean values at 1.08 and 1.1 times. Conclusion: Preheating of light-curing resin-based composites is not equally effective for static and dynamic mechanical properties of materials for dental restoration. Preliminary laboratory tests could have helped before their clinical use

Associations of the SCD1 gene SNP with fatty acids composition of Holstein cows

The research presents the findings of DNA testing of allelic polymorphism by the PCR-RFLP method of the SCD1 gene and the relationship of genotypes with the milk fatty acid composition of Holstein cows of Tatarstan population. The research was conducted among 172 Holstein cows at the Integrated Agricultural Production Centre “Stud farm named after Lenin” in Atninsky district of the Republic of Tatarstan in 2017–2018. All genotypes of the SCD1 gene were identified through the research. The milk yield test showed that the maximum content of the mass fraction of fat was in animals with the TT genotype. The significant difference between the content of the mass fraction of fat in milk in individuals by the locus of the SCD1-Fsp4H I gene was: TT to CC – 0.32 % (p < 0.05) and TT to TC – 0.40 % (p < 0.01). The results of chromatography indicate the balance of the milk fatty acid composition of cows with the TT genotype and, as a consequence, its positive effect on the human body. Cows with a homozygous TT genotype are characterized by the optimum ratio of fatty acids in milk fat. The maximum value of the oxygen desaturation index is also observed in animals with the TT genotype by the SCD1 gene