Effect of silver additive on physicochemical properties of hydroxyapatite applied to reconstructive surgery

The effect of silver adding to hydroxyapatite (HA) in its solubility in physiological solution and biological activity was investigated. Samples of HA containing silver (AgHA) obtained by liquid-phase method in the conditions of microwave exposure. Solubility (CCa2+·103, mol/l) of the powders AgHA was determined by chemical methods according trilonometric titration of the calcium ions in physiological solution at 25 and 37 °C. To investigate the biological activity of the samples, a series of experiments on the formation of the calcium-phosphate layer on the surface of the SBF-solution at 37 °C for 28 days. Electronic micrographs of samples taken at the end of each 7 days of the experiment, indicate the formation of calcium-phosphate layer (CPL) in the samples, the kinetics of which is shown as a function of cumulative concentrations of calcium and magnesium ions from time

Synthesis and investigation of physico-chemical, antibacterial, biomymetic properties of silver and zinc containing hydroxyapatite

In the work we carried out microwave synthesis of modified hydroxyapatites (HA) with different content of ions. A solid solution based on HA remains a single-phase sample when the calcium ions are substituted by silver and zinc ions up to 5 % by weight (0.5 mole fraction). The microstructure parameters, morphology and the particle powders size were studied by X-ray diffraction analysis, IR spectroscopy, and scanning electron microscopy (SEM). It is shown that the modification of НA by silver (AgHA) and zinc (ZnHA) ions increases the size of its particles, the degree of crystallinity, and the pore sizes of the samples while reducing their specific surface and uniformity of their forms. Elemental analysis and distribution of elements over the surface of HA, AgHA, and ZnHA powders were performed by X-ray spectral microanalysis (RSMA). The ratio of Ca/P is within the range of 1.66-1.77 and corresponds to the ratio of Ca/P in stoichiometric HA and the HA entering bone tissue. The ability of AgHA- and ZnHA-substrates to form on their surface a calcium-phosphate layer from the simulated body fluid (SBF) at 37 °C is determined. This ability decreases in the order: in ZnHА it is less than in AgHА, but greater than in HА. The antibacterial activity of the samples was analyzed. The AgHA sample has both bactericidal and persistent bacteriostatic properties in the case of direct contact with Escherichia coli cells

Influence of temperature on the strength of alumina-containing raw materials

The work is devoted to the study of the effect of temperatures on the physical and mechanical properties of an alumina-containing product in order to select crushing and grinding equipment for subsequent enrichment operations. In the course of the study, three series of experiments were carried out: at room temperature 23 °C, with heating the material in a drying chamber to 200 °C, and also under cryogenic exposure – 195,75 °C using liquid nitrogen. As a result, the substantiation of the change in the physical and mechanical properties of raw materials when changing is presented. Recommendations for the selection of crushing equipment have been developed

Influence of temperature on the strength of alumina-containing raw materials

The work is devoted to the study of the effect of temperatures on the physical and mechanical properties of an alumina-containing product in order to select crushing and grinding equipment for subsequent enrichment operations. In the course of the study, three series of experiments were carried out: at room temperature 23 °C, with heating the material in a drying chamber to 200 °C, and also under cryogenic exposure – 195,75 °C using liquid nitrogen. As a result, the substantiation of the change in the physical and mechanical properties of raw materials when changing is presented. Recommendations for the selection of crushing equipment have been developed

TREATMENT OF TRIPLE-NEGATIVE BREAST CANCER

The rate of triple-negative breast cancer is 10–24  %, and in recent years it’s one of the most studied subtypes of breast cancer due to its clinical aggressiveness and a small number of molecular targets.The study objective is to evaluate effectiveness of different NAPCT regimens including their dependence on the presence of mutations in the ВRСА 1, 2, СHEK2 genes.Materials and methods. The study included 40 female patients with triple-negative breast cancer. The patients were monitored from 2012 to 2016; surgical treatment was performed at the P.A. Hertzen Moscow Oncology Research Institute – branch of the National Medical Research Radiological Center, Ministry of Health of Russia. Median patient age was 45.9 (31–69)  years. All patients received neoadjuvant polychemotherapy (NAPCT) per different regimens. Then the patients underwent surgery of different volume (from radical mastectomies to resections), and in 25 % of cases reconstructive breast surgery was performed. In 5 patients with BRCA1, – 2 mutations, prophylactic subcutaneous mastectomy with immediate reconstruction with an implant was performed; 2 patients refused prophylactic mastectomy; in 1 patient with СНЕК2 mutation, metachronous multiple primary breast cancer was diagnosed, previously she didn»t undergo prophylactic mastectomy, and 6 years later cancer in the second breast was diagnosed.Results. The study included 11 patients under 40 (27.5 %), 4 (50 %) of them in the group with mutations in ВRCA1, -2, CHEK2.The study demonstrated high effectiveness of NAPCT regimens per the АС + Т scheme and weekly injections of doxorubicin 25 mg/m2, cisplatin 30 mg/m2, and paclitaxel 100 mg/m2. Grade IV treatment pathomorphosis for NAPCT per АС + Т scheme was achieved in 50.0 ± 7.9 % cases, for intensified regimen – in 62.5 ± 12.5 % cases.Median follow-up duration for this patient group was 22.1 months, and during this time disease progression was observed in 3 patients: in the 1st patient continued growth on the thoracic wall and brain metastases were diagnosed, in the 2nd patient – lung and supraclavicular lymph nodes metastases, in the 3rd patient – metastases in the cerebellum. In all of these patients, grade IV treatment pathomorphosis wasn»t achieved. Conclusions. The study demonstrated high effectiveness of NAPCT in patients with triple-negative breast cancer of different stages: objective response rate was 90.0 ± 4.7 %, grade IV treatment pathomorphosis was 50.0 ± 7.9 %.Grade IV treatment pathomorphosis for NAPCT per АС + Т scheme was achieved in 50.0 ± 7.9 % cases, for intensified regimen – in 62.5 ± 12.5 % cases. Rate of grade IV treatment pathomorphosis was higher in patients with hereditary form of the disease (62.5 ± 18.3 %) compared to the group with sporadic breast cancer (46.9 ± 8.8 %), р >0.05. In all patients, 2-year disease-free survival was 92.5 %, 2-year overall survival was 95 %

Bioactivity and physico-chemical properties of composites on basis of hydroxyapatite with lactic and glycolic acids oligomers

A new method in situ for producing of biocompatible composites based on hydroxyapatite and oligomers of lactic and glycolic acid is described. Their thermo-mechanical, physical-chemical and biological properties are studied as well. The formation of bonds between hydroxyapatite with lactic and glycolic oligomers in composites are confirmed by IR spectroscopy of the samples, including those obtained in the Soxhlet apparatus. The formation of calciumphosphate layer on the surface of composite containing hydroxyapatite was shown by SBFinvestigation. The scaffolds based on lactic acid oligomer do not stimulate formation of a calciumphosphate layer and they are subjected to destruction by the way of hydrolysis

Тактика лечения рака молочной железы у пациентки с почечным трансплантатом

Objective – the choice of tactics for the treatment of breast cancer in a kidney transplant recipient. The article presents a clinical case of a 51-year-old patient with a clinical diagnosis: left breast cancer IIA stage рТ2N0М0G3; triple-negative type. About chronic renal failure 10 years ago the patient was kidney transplantation was performed. The development of transplantation has expanded the use of immunosuppressive therapy in clinical practice. As a result, the risk the development of secondary tumors, including breast cancer, increases.Цель исследования – выбор тактики лечения рака молочной железы у реципиента почечного трансплантата. В статье представлено клиническое наблюдение пациентки 51 года с клиническим диагнозом: рак левой молочной железы IIA стадии рТ2N0М0G3; тройной негативный тип. По поводу хронической почечной недостаточности 10 лет назад пациентке была выполнена трансплантация почки. Развитие трансплантологии расширило применение в клинической практике иммуносупрессивной терапии. В результате риск развития вторичных опухолей, в том числе рака молочной железы, возрастает

An International Study on Psychological Coping During COVID-19: Towards a Meaning-Centered Coping Style

Background/Objective This study examined the role of different psychological coping mechanisms in mental and physical health during the initial phases of the COVID-19 crisis with an emphasis on meaning-centered coping. Method A total of 11,227 people from 30 countries across all continents participated in the study and completed measures of psychological distress (depression, stress, and anxiety), loneliness, well-being, and physical health, together with measures of problem-focused and emotion-focused coping, and a measure called the Meaning-centered Coping Scale (MCCS) that was developed in the present study. Validation analyses of the MCCS were performed in all countries, and data were assessed by multilevel modeling (MLM). Results The MCCS showed a robust one-factor structure in 30 countries with good test-retest, concurrent and divergent validity results. MLM analyses showed mixed results regarding emotion and problem-focused coping strategies. However, the MCCS was the strongest positive predictor of physical and mental health among all coping strategies, independently of demographic characteristics and country-level variables. Conclusions The findings suggest that the MCCS is a valid measure to assess meaning-centered coping. The results also call for policies promoting effective coping to mitigate collective suffering during the pandemic