The article presents an algorithm for developing a step-by-step method for producing silver nanoparticles 30-35 nm in size, taking into account the establishment at each stage of the necessary ratio of concentrations and volumes of reagents. In the work, silver nitrate and sodium citrate anhydrous were used by «Sigma-Aldrich» (USA). All test solutions were prepared by the gravimetric method. To weigh the reagents, we used Adventurer electronic analytical balances («OHAUS», USA) (with a resolution of 0.0001 g). The size and density of silver nanoparticles were estimated using a JEM-1011 electron transmission microscope («Jeol», Japan). In the course of the study, a direct dependence of the size of the nanoparticles on the concentration of solutions of sodium citrate and silver nitrate was established. According to the results of the first stage, the concentration ratio of AgNO3 : Na3C6H5O7 – 1 : 0.75 was chosen for testing the synthesis of colloidal silver nanoparticles. At the second stage, the influence of the ratios of the volumes of reagents on the conditionability of the obtained series was evaluated. The best result was obtained in the series with the volume ratio of AgNO3 : Na3C6H5O7 – 5 : 1, where single conglomerates were observed, and the particle shape was regular and round. At the next stage, the optimal boiling time of the colloidal solution after the appearance of a light yellow color was experimentally determined. With an increase in the boiling time of the solution, stabilization of particles occurs, thereby aggregative stability is observed. The most appropriate reagent mixing mode using a magnetic stirrer was selected: after the appearance of a light yellow color, the number of revolutions was changed from 375 to 500 rpm and the temperature regime was decreased from 300 °C to 200 °C.
Multiple epiphyseal dysplasias (MED) are a clinically and genetically heterogeneous group of skeletal dysplasias with a predominant lesion in the epiphyses of tubular bones. Variants in the SLC26A2 gene cause their autosomal recessive form (rMED or MED type 4). The accumulation of data regarding the genotype–phenotype correlation can help in the diagnosis and proper management of these patients. The aim of this study was to survey the clinical and genetic characteristics of 55 patients with MED type 4 caused by variants in the SLC26A2 gene. Diagnosis confirmation was carried out by radiography and custom panel sequencing consisting of 166 genes responsible for the development of hereditary skeletal pathology. This was followed by the validation of the identified variants using automated Sanger sequencing (for six patients) and the direct automatic Sanger sequencing of the coding sequence and the adjacent intron regions of the SLC26A2 gene for 49 patients. Based on the clinical and genetic analysis of our sample of patients, two main MED type 4 phenotypes with early and late clinical manifestations were identified. An early and more severe form of the disease was observed in patients with the c.835C > T variant (p.Arg279Trp), and the late and milder form of the disease was observed in patients with the c.1957T > A variant (p.Cys653Ser) in the homozygous or compound heterozygous state with c.26 + 2T > C. It was also shown that only three pathogenic variants were found in 95.3% of the alleles of Russian patients with MED type 4: c.1957T > A (p.Cys653Ser), c.835C > T (p.Arg279Trp), and c.26 + 2T > C; thus, it can be assumed that the primary analysis of these variants will contribute to the optimal molecular genetic diagnostics of MED type 4.
BACKGROUND: Achondroplasia and pseudoachondroplasia are hereditary systemic skeletal dysplasias characterized by a certain similarity of clinical manifestations; however, they have different etiopathogenetic mechanisms and confirmation methods for molecular genetic diagnosis. Their common phenotypic features often make differential diagnosis difficult during the clinical examination of patients, planning DNA diagnostics, and appropriate time detection of neurosurgical and orthopedic complications. AIM: This study aimed to identify differential diagnostic criteria for achondroplasia and pseudoachondroplasia and optimize the strategy for their molecular genetic diagnosis. MATERIALS AND METHODS: A comprehensive examination of 76 children from 74 unrelated families aged 1 month to 18 years with phenotypic signs of achondroplasia and pseudoachondroplasia was conducted. To clarify the diagnosis through genealogical and amnestic analysis, clinical and neurological examination data according to the standard method and radiographic data were used. Molecular genetic confirmation of diseases was conducted by searching for hotspot mutations in the FGFR3 gene, assessing the number of GAC repeats located in exon 13 of the COMP gene, and new-generation sequencing of the target panel consisting of 166 genes responsible for hereditary skeletal pathology. RESULTS: Based on a comparative analysis of the specific phenotypic characteristics, the criteria for the differential diagnosis of achondroplasia and pseudoachondroplasia were identified. The leading signs of achondroplasia are disproportionate nanism from birth, macrocrania, and facial dysmorphism, which are not specific to pseudoachondroplasia. Certain radiological features are essential in the differential diagnosis of pseudoachondroplasia, which should be considered when referring to patients for molecular genetic analysis. A deletion of the GAC repeat c.1417_1419del in the COMP gene was identified in 27% of patients with pseudoachondroplasia. Thus, the analyses of these two mutations in FGFR3 and COMP were conducted first. In the absence of target mutations, further diagnostic search should be continued with a target panel consisting of 166 genes responsible for hereditary skeletal pathology or whole-exome sequencing. CONCLUSIONS: The analysis of the clinical, radiological, and molecular genetic characteristics of patients with achondroplasia and pseudoachondroplasia, together with the literature data analysis, made it possible to clarify the differential diagnostic criteria for these diseases and optimize the algorithm for their molecular genetic diagnosis.
Relevance. The oral hygiene and prevention quality depends on toothpaste. The literature analysis shows the underuse of saliva biochemical parameters for assessing oral hygiene product effectiveness.Materials and methods. Thirty-three subjects aged 19 to 22 years participated in the study. The participants used four kinds of toothpaste by the same manufacturer to evaluate the toothpaste’s effectiveness. We conducted clinical examinations and collected saliva samples on the 1st, 14th and 28th days of the study. The saliva was collected on an empty stomach without stimulation in the morning. Then it was centrifuged. The supernatant was biochemically studied.Results. The study established the criteria for the toothpaste’s low effectiveness, which involve a signifcant increase in hygienic indices and total antioxidant activity, associated with a statistically signifcant trend towards an increase in lactate content. The criteria for a toothpaste with medium effectiveness are a signifcant decrease in one of the hygienic indices, associated with an alkaline pH shift, and an increase in the total antioxidant activity, without signifcant changes in the lactate content. The criteria for a highly effective toothpaste are a signifcant decrease in hygienic indices, and an alkaline pH shift, associated with a signifcant lactate decrease. Determination of total calcium and inorganic phosphorus in the oral fluid may be crucial for assessing the toothpaste remineralizing properties. The glucose content in mixed saliva yields little information for the toothpaste’s hygienic effectiveness assessment.Conclusion. We can recommend saliva biochemical parameters for assessing the oral hygiene status and the effectiveness of oral hygiene products during oral hygiene product comprehensive studies.
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