61 research outputs found
Clinical Justification for Preliminary Thermal Exposure to Composite in the Treatment of Caries: Randomized Clinical Trial
Background. Polymer composites have good aesthetic characteristics and pronounced physicochemical properties, as compared to traditional restorative materials such as amalgam. However, the polymerization reaction of composite material containing bismethacrylate group commonly used in clinical practice is always accompanied by a different degree of volumetric shrinkage (2.7%~7.1%). The resulting stress can lead to adhesion failure and some other unfavorable clinical consequences, such as enamel destruction, microcracking of composite material and formation of microleakage between composite and tooth cavity wall, which can result in recurrent caries and postoperative sensitivity, thereby affecting the long-term effect of restoration. Therefore, studying the effect of preheating on composite restoration is important for its clinical application. Objective. To improve the effectiveness of treatment of patients with dental caries by improving the physicochemical properties of composite restorations.Methods. A randomized clinical trial enrolled 180 patients aged 18 to 45 years, diagnosed with dentin caries class I, according to Black (K02.1 in ICD). The study was conducted in the Dental Clinic of Kuban State Medical University, Russia. 180 composite restorations were performed in the treatment of dentin caries of molars. Patients were randomized into 2 groups): the control group — 90 patients and the main group — 90 patients. The control and main groups, in turn, were divided into three subgroups, depending on the composite used — Estelite Sigma Quick (Tokuyama Dental, Japan), Filtek Bulk Fill Posterior Restorative (3M Espe, USA) and DentLight (VladMiVa, Russia). Each subgroup consisted of 30 patients. In the control group, the classical method of filling with a composite material at “room temperature” was applied. In the main group, a composite heating conditioner “Ena Heat” (Micerium, Italy) was used to heat the composite to 55 °C before adapting the material in the formed cavity with subsequent photopolymerization. The quality of composite restorations within the clinical study was evaluated using the modified Ryge criterion immediately after treatment and after 6, 12, 18, 24 months. Statistical processing of the obtained data was carried out by means of one-factor analysis of variance using the GraphPadPrism 9 program (GraphPad Software, USA).Results. The duration of the clinical study comprised 24 months. The study revealed a statistically significant decrease in the quality of marginal fit of composite restorations (according to the Ryge score) by 20.1% (p = 0.0001) in the control group and by 5.7% (p = 0.0328) in the main group. At the same time, no statistically significant changes in Ryge scores were reported in the subgroups of composite materials of the main group (pF = 0.9480, pE = 0.1837, pD = 0.2529). As a result of the study, an optimal time algorithm (7 seconds) for using a special furnace for preheating the composite before sealing with subsequent photopolymerization was obtained.Conclusion. The study revealed a statistically significant positive effect of the proposed algorithm for working with a heated composite on the quality of marginal fit in the long term after treatment in comparison with the classical method of working with a composite at “room temperature”
Universality of finite-size corrections to the number of critical percolation clusters
Monte-Carlo simulations on a variety of 2d percolating systems at criticality
suggest that the excess number of clusters in finite systems over the bulk
value of nc is a universal quantity, dependent upon the system shape but
independent of the lattice and percolation type. Values of nc are found to high
accuracy, and for bond percolation confirm the theoretical predictions of
Temperley and Lieb, and Baxter, Temperley, and Ashley, which we have evaluated
explicitly in terms of simple algebraic numbers. Predictions for the
fluctuations are also verified for the first time.Comment: 13 pages, 2 figs., Latex, submitted to Phys. Rev. Let
Структура и функции ароматазы и ее нестероидные ингибиторы
The analysis of the structure and function of aromatase (SYP19) - enzyme from the family of cytochrome P-450 that catalyzes the aromatization of six-membered ring A of the steroidal skeleton, namely transformation of androgens into estrogens peripheral and tumor tissues in the body, has been performed, and data in its non-steroidal inhibitors have been summarized.Проведен анализ структуры и функции ароматазы (СYP19) - фермента семейства цитохромов Р-450, кодируемого расположенным на коротком плече 15-й хромосомы (локус 15q21) геном CYP19A1, катализирующего ароматизацию шестичленного цикла А стероидного скелета и обуславливающего метаболизм стероидных гормонов, а именно трансформацию андрогенов в эстрогены периферическими и опухолевыми тканями организма. Обобщены данные по ее нестероидным ингибиторам. Обсуждены особенности первичной и пространственной структуры СYP19, обуславливающие взаимодействие с мембраной клетки и субстратом, обеспечивающие транспорт последнего между липидным бислоем мембраны и активным центром фермента. Показано, что наиболее эффективными ингибиторами СYP19 в настоящее время являются соединения, содержащие в составе молекулы азольные и азиновые гетероциклические фрагменты
Dexmedetomidine is neuroprotective in an in vitro model for traumatic brain injury
<p>Abstract</p> <p>Background</p> <p>The α<sub>2</sub>-adrenoreceptor agonist dexmedetomidine is known to provide neuroprotection under ischemic conditions. In this study we investigated whether dexmedetomidine has a protective effect in an <it>in vitro </it>model for traumatic brain injury.</p> <p>Methods</p> <p>Organotypic hippocampal slice cultures were subjected to a focal mechanical trauma and then exposed to varying concentrations of dexmedetomidine. After 72 h cell injury was assessed using propidium iodide. In addition, the effects of delayed dexmedetomidine application, of hypothermia and canonical signalling pathway inhibitors were examined.</p> <p>Results</p> <p>Dexmedetomidine showed a protective effect on traumatically injured hippocampal cells with a maximum effect at a dosage of 1 μM. This effect was partially reversed by the simultaneous administration of the ERK inhibitor PD98059.</p> <p>Conclusion</p> <p>In this TBI model dexmedetomidine had a significant neuroprotective effect. Our results indicate that activation of ERK might be involved in mediating this effect.</p
PREDICTING THE RISK OF ATRIAL FIBRILLATION AND CORONARY HEART DISEASE DEVELOPMENT WITH MUTATION OF HEMOSTASIS SYSTEM GENES
Aim. This study was conducted to assess the risk of atrial fibrillation and coronary heart disease development with mutation of hemostasis system genes.Materials and methods. Genes polymorphisms of factor GII210A II (FII), G169A factor V (FV), Arg 353G1p factor VII (FVII), C677T MTHFR, 22Met (66a-g) MTRR, 675 5G / 4G PAI type 1 and 455G-A fibrinogen β (FGB) were examined in the patients of the main group and control group. The genotyping was carried out by PCR method using competing TagMan probes complementary to the polymorphic region of DNA.Results. As a result of the research, there was identified a reliable prognostic risk of the development of coronary heart disease (CHD) and atrial fibrillation paroxysms (AFP) in patients with mutations of the VII blood coagulation factor genes, mutations in the MTHFR gene, mutations in the MTRR gene.Conclusion. The obtained results indicate the risk of CHD and AFP development in patients with mutations of the VII gene of the clotting factor, mutation in the MTHFR gene and mutation in the MTRR gene. It may be the basis for early diagnosis, monitoring and treatment of this category of patients
LABORATORY AND GENETIC PREDICTION OF THE RISK OF ATRIAL FIBRILLATION IN PATIENTS WITH CORONARY HEART DISEASE
The paper studied the frequency of polymorphisms of hemostasis in patients with coronary heart disease, living in the Krasnodar region. Of the 13 patients with atrial fibrillation documented confirmed, 11 patients revealed mutations of genes of the hemostatic system (84.61 %), while 10 patients out of 11 had a mutation MTRR mutation (90.9 %), and met mutations in polygenic 10 cases (90.9 %). It is shown that the most common mutation MTRR gene, PAI, VII factor and beta fibrin often cause arrhythmias in patients enhance remodeling of the left ventricle, especially in polygenic mutations
GENETIC RISK FACTORS OF TROMBOPHILIA IN WOMEN OF REPRODUCTIVE AGE RESIDING IN KRASNODAR REGION
Оur paper presents the study of incidence rate of genetic polymorphism of hemostasis genes and folate cycle in patients with habitual miscarriage, residing in Krasnodar region. The property of reproduction age women with habitual miscarriage in juvenile age (75 patients) was the multigene nature of trombophilia in 76.81% of cases (53 patients) from 69 patients with mutations (92% of total number of studied patients) at low percent of incidence of factor V (Leiden) and factor II (prothrombin) gene mutation. It shows that the management of pregnant women, decision on COCs and HRT administration can’t be made with testing of a limited number of the most thoroughly studied genes, considered as unconditional and strict markers of inherited thrombophilia (FV, F II, MTHFR С677Т)
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