MATHEMATICAL JUSTIFICATION OF THE CHOICE OF RODS FOR EXTERNAL FIXATION DEVICES FOR POLYSTRUCTURAL PELVIC INJURIES.

Aim - In order to fulfill the purpose of biomechanical substantiation for extrafocal pelvic osteosynthesis in osteoporosis we studied the stress-strain state (SSS) of LEG under conditions of external fixation by apparatuses with cylindrical and conical rods. Studies of the stress-strain state of the lower extremity belt by the finite element method were carried out under conditions of external fixation by devices with cylindrical and conical rods. In the finite element method, the approximate solution is constructed as a superposition of approximating functions. At the first stage of solving the problem, the object is divided into areas of a simpler form - finite elements whose geometric dimensions are significantly smaller than the dimensions of the entire biomechanical system. Modern software systems generate finite elements of the grid automatically using elements with triangular faces in most cases. At the junctions of the elements (nodal points), the real stress field is replaced by the action of forces and movements. The type of finite elements is characterized by the number of nodes and the degree of approximation of unknowns within the domain and largely determines the accuracy of the resulting solution in the finite element method. Various types of biological tissues were taken into account in the conducted studies: compact and spongy bone, cartilage tissue, intervertebral disc, ligaments. In this study, the material was considered homogeneous and isotropic. The main load is body weight. In the calculation, the body weight was taken to be equal to 700 N. The geometric model was built on the basis of tomographic sections of the pelvis carried out through 0.5 - 1 cm for irregular zones. A pelvis with rotationally unstable (type B1 according to AO classification) damage after osteosynthesis by an external fixation device was modeled in the variants of using cylindrical and conical rods. Mises stresses were used to assess the stress state. The resulting model consists of 75,845 finite elements and has 132253 nodes. The construction of the geometric model was carried out in the SolidWorks program. VAT calculations and analysis were carried out in the ANSYS program. In the first variant of the study of the pelvic model with normal bone tissue and cylindrical rods, the calculation results showed that with a single support standing (support on the left limb), the supporting side with pronounced stress concentration zones in the sacroiliac joint, the place of entry of the rod into the bone and in the area of reducing the thickness of the iliac wing is more tense. Two stress concentration zones are observed along the passage of the rod. The most intense is the area of the screw entry into the bone (18.5 MPa). There is also an area of increased stress at the site of a decrease in the thickness of the iliac wing (8.1 MPa), where the rod passes closest to the cortical layers. The calculation of the model using conical shaped rods showed that the nature of the VAT distribution for the model as a whole has not changed, and the stress state level has decreased. So, at the point of entry of the screw into the bone, the value of the Mises stresses is 16.4 MPa, and at the point of reduction of the thickness of the iliac bone - 6.3 MPa. It is worth noting that the area with an increased stress state along the passage of a conical rod is smaller than for a cylindrical one. In the second variant of the study for a pelvic model with osteoporotic bone tissue, a comparative analysis of VAT when using cylindrical rods of an external fixation device showed that the general nature of the distribution of stresses and deformations for the model as a whole did not change, but the VAT level increased. At the point where the screws enter the bone, it is 28.4 MPa, at the point where the thickness of the iliac wing decreases - 9.1 MPa. The level of tension has also increased throughout the "rod-bone" contact. A comparative analysis of VAT for the variant of conical rods of the external fixation apparatus and osteoporotic bone tissue showed that the general nature of the VAT distribution for the model as a whole has not changed, and the level of stress state has increased as well as in the model with cylindrical screws. At the point where the screws enter the bone, it is 26.5 MPa. At the site of the reduction in the thickness of the iliac wing, the stress level is 7 MPa. The use of conical shaped rods in the external fixation device of the pelvis makes it possible to reduce the level of stress-strain state both in the area of the entry of screws into the bone and in the area of the thinnest part of the iliac wing. For external osteosynthesis of the pelvis in polystructural injuries, lowering the stress state when using conical rods plays an important role, since the strength characteristics of osteoporotic bone tissue are significantly lower than those of normal. Thus, the use of conical rods in external pelvic fixation devices improves the strength characteristics of the "pelvis - rod" system, which makes it possible to recommend their testing in clinical practice.

A multiparametric classification system for lesions detected by breast magnetic resonance imaging.

BACKGROUND: To validate a new categorisation scheme for suspicious breast lesions according to the well-defined Breast Imaging Reporting and Data System (BI-RADS) magnetic resonance imaging (MRI) lexicon descriptors, apparent diffusion coefficients (ADC), T2-weighted signal intensity (SI), and kinetic curve assessment categories. METHODS: The MRI descriptors and ADC were analysed in 697 lesions detected in 499 subjects. The descriptors were classified into Minor, Intermediate, and Major findings, and were divided into the BI-RADS subcategories 3, 4A, 4B, 4C, and 5 according to the number of descriptors. Positive predictive values (PPV) were calculated for each descriptor. The descriptors were then fitted into a multinomial logistic regression model to determine the odds ratio for a malignant diagnosis. The PPV were measured for the new categories and compared with the assigned PPV of the BI-RADS descriptors. RESULTS: The PPV for MRI descriptors ranged from 17.9%-100%. Of the 697 lesions assessed, 19 (2.7 %) were categorized as BI-RADS 3, 27 (3.9 %) as 4A, 53 (7.6 %) as 4B, 174 (25.0 %) as 4C, and 424 (60.8 %) as 5. None of the subjects in BI-RADS category 3 had a malignant diagnosis. The PPV for malignancy increased progressively with increasing BI-RADS category (4A, 11.1 %; 4B, 28.3 %; 4C, 64.4 %; 5, 94.8 %). All descriptor groups were significant in the logistic regression model. CONCLUSIONS: This study shows that using BI-RADS MRI descriptors together with ADC and T2-weighted SI in a multiparametric classification system can yield an applicable categorisation of lesions with PPV values within the recommended ranges for BI-RADS categories.

[Analysis of adequacy of actual nutrition for athletes at training camps].

An increase in special performance in elite sports requires optimization of the metabolic parameters of the organism at all stages of the annual training cycle. In this regard, it is relevant to analyze the adequacy of the actual nutrition of athletes, taking into account the energy expenditures of training loads in different seasons of the year. The aim of this study was to analyze the integral adequacy and balance of the main and essential components of the diet of athletes in different seasonal periods of the annual training cycle. Material and methods. 20 highly qualified road cyclists (the average age 22.4± 0.7 years) have been examined. Individual energy expenditures of the subjects has been determined, the actual nutrition of athletes was studied by the method of 24-hour dietary recall. In different seasons of the year, in the conditions of training camps, 1540 dietary rations of athletes have been analyzed over 5 years. The study of the energy balance and the adequacy of the actual nutrition was carried out using the developed author's automated system "FP Diet". Results. The average daily energy consumption of cyclists at different stages of the annual training cycle ranged from 4503±69 to 4646±88 kcal, which indicates that athletes belong to one of the energy-intensive sports. The calorie intake practically satisfied the average daily energy expenditures, however, the low values of the integral indicator of adequacy (43.2% for the winter-spring season and 60.0% for the summerautumn season) indicated significant imbalances in the actual diet for the main and essential nutritients, especially noticeable in the groups of vitamins and fatty acids. Against the background of insufficient consumption of vegetable oils, which causes a lack of monounsaturated fatty acids in the diet, an excessive consumption of saturated fatty acids, a deficiency of vitamins B1 and B2, a lack of vitamin C in the winter-spring period, as well as calcium and magnesium deficit have been revealed. Conclusion. The qualitative characteristics of the diet of cyclists in different seasons of the annual training session does not meet the physiological needs of the organism. Optimization of athletes' nutrition in terms of calorie content and chemical composition must be carried out taking into account the nature and methods of the training cycle, which have significant differences in the energy orientation of the loads and daily energy expenditures.

[Using of specialized food for the workers with skin occupational eczema of perlite production].

The research was conducted with participation of the perlite production workers with professional eczema (165 people in the main group and 152 from the control group without skin pathology). The effectiveness of the use of a specialized prophylactic food in the diet of workers was assessed on the basis of the study of the dynamics of the indicators of nutritional and clinical status. Inclusion of kissel, containing pectin, vitamin A (300% from RDA), vitamin E and zinc (40% from RDA), biologically active substances of plant origin in the diet of the examined against the background of the course of complex therapy, has resulted in a positive influence on individual laboratory values, demonstrating the optimization of metabolic processes, which characterize the pathogenesis of skin inflammation. Thus, the concentration of ascorbic acid in blood serum statistically significant (p<0.05) increased by 30.0%, tocopherol - by 36.3%, carotenoids - by 27.3%, phosphorus - by 28.9%, calcium level elevated by 16.3% (p<0.10). There was a decrease in the level of MDA in blood serum by 12.3% (p<0.05) and an increase in catalase activity by 12.2% (p>0.05). There was a tendency to reduce itching, infiltration, erythematous and eczematous manifestations of the disease. The data obtained make it possible to consider the use of a specialized food product of dietary preventive nutrition by workers in pearlite production as a mean to enhance the body's adaptive reserves and to prevent the occurrence, progression and development of occupational skin diseases (eczema) in the workplace.

[Evaluation of preventive effectiveness of food products by community-acquired pneumonia with unknown causative agent].

The aim of the study is to evaluate a preventive effectiveness of food products with elevated content of biologically active substances by community-acquired pneumonia with unknown causative agent. The authors studied two groups of youngsters (18 years old) during period of adaptation to conditions of organized group: with normal nutritional status [with body mass index (BMI) = 19.5-22.9 kg/m2] and decreased one (with BMI = 18.5-19.4 kg/m2). Tumor necrosis factor (TNFα) and interleukin 1α (IL-1ß) levels in blood serum were criteria of degree of inflammatory process. Functional activity of phagocytes was also evaluated with the use of nitroblue tetrasol test (NTT-test). To prevent pneumonia natural concentrated food product made of vegetable raw materials (3.0 g per day) by cryogen technology was added in diet of persons with normal nutritional status during two periods (15 days) with an interval (30 days). But persons with decreased nutritional status got the product made of protein-vegetable raw materials during 15 days only and additionally product made of protein-vegetable raw materials by cryogen technology one time per day (35.0 g) during 15 days. The persons with normal nutritional status were divided in three group: persons (480 men) in the first group got the product only, persons (100 men) of the second group underwent vaccination with polysaccharide polyvalent «Pneumo-23¼ vaccine only, persons (316 men) of the third group underwent vaccination in combination with the product intake. The persons (231 men) with decreased nutritional status composed one group and got the food product only. Control group consisted of 263 men with normal nutritional status. The authors evaluated incidence rates during three months of observation and duration of in-patient treatment. The results were compared with data obtained in baseline period (the same time periods during three years before the study). The authors received data on the decrease of a reserve ability of phagocytes; it provided evidence about an initial deficiency of immune protection factors in persons with decreased nutritional status. In adaptation period, this phenomenon was observed in persons with normal nutritional status too. The including of protein-vegetable product in diet promoted the increase of bactericidal function of neutrophils and body weight among youngsters with decreased nutritional status; but including of vegetable product kept bactericidal function of neutrophils on normal level. In adaptation period, TNFα levels increased in both groups by 21.0 and 35.1%, respectively; IL-1ß level did not significantly change in group with normal nutritional status, but increased 2.25 fold in persons with decreased nutritional status. The levels of studied cytokins decreased to baseline values in 30 days after the product intake. To this time, TNFα increased 1.8 fold and IL-1ß increased 2.86 times in control group. A preventive effectiveness of the especially created products in nidus with unknown causative agent was confirmed by the decrease of incidence rate (82.4-78.4%) in persons with normal and lower nutritional status that coincided with effectiveness of a vaccinal prevention only. The food product with antioxidant properties potentiated a vaccinal prevention. The positive effect consisted in lack of fatal outcomes and outbreaks of the disease; mean bed-day decreased on 3.5 days; predominance of mild form of the disease in clinical picture in comparison with same parameters during basic period of observation.

[Cytogenetic indices of buccal epithelium in schoolchildren residing in territories with different levels of the air pollution].

In the article there are contained the results of the study of ambient air of the regional center, urban-type settlement, and buccal epithelium in 87 schoolchildren aged of 11-13 years. Schoolchildren residing in the regional center were shown to be more susceptible to the exposure to such toxicants as carbon monoxide, nitrogen oxide, fluorhydric acid, chlorine and its compounds, sulfur dioxide, formaldehyde contained in the ambient air. In this group of students if compared with students who live in the village, there were revealed more pronounced cytogenetic deteriorations in oral mucosal epitheliocytes: cells with micronuclei, different forms of protrusion of the core, dual-core cell mitosis, kariokynesis, apoptotic bodies significantly more common occur, that can speak about both not only of cytogenetic instability, but and the degree of environmental genotoxicity, in particular, ambient air. There was noted the tendency to increase the level of cytogenetic damage and destruction of the nucleus in the group of girls in comparison with boys.

[Regional features of food standards and health risks associated with chemical contamination of food].

In the article there are presented results of a study of the balance of food consumption by the population of the Voronezh region, the assessment of the level of contamination of food products and both carcinogenic and non-carcinogenic and public health risk caused by this contamination. There was evaluated the level of nutrition-dependent diseases. A special feature of this study is a comparative analysis of data obtained during the two five-year periods of 1995-1999 and 2010-2014, that permitted to reveal changes in food consumption, the dynamics of morbidity rate associated with the nutritional factor.

[Topical problems and prospects of industrial medicine nowadays (according to materials of scientific and practical conferences of 2014)].

The article presents results of scientific and practical conferences on occupational medicine problems, that were held in Moscow, St-Petersburg, Rostov-na-Donu, Nizhny Novgorod, Sochi, Irkutsk, Angarsk. Prospective trends of research work and practical implementation in occupational medicine and industrial ecology are set.

[Hygienic aspects of iodic deficiency in the children's population of the Saratov region].

The analysis of clusters of iodine-scarce states formation among the children's population of the Saratov Region is submitted. The hygienic assessment of iodine content in raw food materials and foodstuffs grown up and made on the territory of the Saratov Region is given. It has been revealed that various food groups were characterized by a low iodine content, which was (mcg/100 g) in the bread--4.5 +/- 1.0; 3,6 +/- 0.8 in wheat grain; 2.7 +/- 0.6 in buckwheat; 2.5 +/- 1.1 in beans; 1.95 +/- 0.9 in peas. The actual iodine content in local vegetables and fruits was 1.3-1.6 fold below than the standard chemical composition according to the national tables, in river fish--twice. The quality analysis of the iodated salt sold in the trading network has been carried out. It has been found out that the use of the iodated salt with low iodine content has decreased the additional direct population risk from 12.34% in 2000 to 0.48% in 2010. For the last few years the use of the iodated salt tends to increase in the Saratov Region. In 2011 the iodated salt was used by 37.2% of urban population and 29.0% of villagers. In 2011 88.6% of school students were provided with the iodated salt in educational institutions of the area. It has been shown that the formation of mass iodine-scarce states among the population in the Saratov Region has lasted for a long time. The screening researches of urine excretion in the organized groups of surveyed children revealed an average level of iodine deficiency. In 2011 the iodine deficiency of moderate degree was registered in 18 areas of the Saratov Region, in 6--of easy degree, whereas the moderately severe deficiency areas were not registered.

[Effeciency of usage of natural low caloric protein-vegetable product by patients with excess body weight and hypertension].

The efficiency of the usage of natural low caloric concentrated protein-vegetable food product (LCCF) by 23 persons with excess body weight at the age of 30-44 years (the 1st group) and 30 hypertensive patients at remission stage and overweight at age 45-59 years old (the 2nd group) has been assessed. According to energy expenditure, all examined male persons were classified to II group of physical activity: PhysicalActivity Coefficient (PAC) was 1,35±0,14 and 1,34±0,22 respectively. As for dietary intake, authors revealed an excess of protein (up to 20,1%), fat (up to 17,2%) and daily caloric content over daily energy expenditure that led to an increase of body weight along with metabolic and liver function disorders. Initially, body mass index (BMI) was 29,9±0,6 kg/m2 in the 1st group and 36,2±0,4 kg/m2 in the 2nd group. LCCFP was administrated to persons in studied groups and consisted of fat-free curd, egg white, rye bran, dried apricots, laminaria, leaves of green tea and cowberry. The product was made by cryogenic technology. LCCFP (35 g) was administrated two times per day instead of breakfast and supper during 15 days. Protein content in 1 portion of LCCFP was 5.2 g, fats -3.8 g, carbohydrates - 16.8 g; energy value - 122 kcal. The decrease of daily caloric content was 1225,5 kilocalories (kcal) in the 1st group and 1071,3 kcal in the 2nd group duringperiod of LCCFP administration; the energy value of the diet amounted to an average of 1420 and 1560 kcal per day. During the study, authors found serum protein indices were constant, but revealed the decrease of the level of glucose (by 15,3-18%), cholesterol (18,8-19%), low density lipoprotein cholesterol (13,9-15,8%), triglycerides (20-26,3%) and alanine aminotransferase (39,7-41,4%) and asparagine aminotransferase (40,6-40,7%) activity. This provided evidence of positive influence of the natural protein-vegetable LCCFP on fat and carbohydrate metabolisms as well as liver function. Also, the decrease of atherogenicity index (1,45-1,5 units) gave evidence of effectiveness of used method. The decrease of systolic arterial pressure (by 12,9%) and diastolic arterialpressure (by 20,7%) in patients with hypertension at remission stage and body weightprovided evidence of positive influence of caloric content decrease due to LCCFP administration on function of cardiovascular system in this category of examined persons.

[Toxicological-hygienic assessment of the low-alcohol tonic (energizing) carbonated drinks].

The impact of the low-alcohol tonic (energizing) carbonated drinks on biochemical and hematological indices, on the functional state of the central nervous system and cardiovascular system was studied within the experiment over the outbred white male rats. The gained results were compared to indices of animals receiving the same concentrated solution of ethanol used for drinks preparation as well as to figures of intact group animals. The results gained from all compared animals groups had no significant differences.

[Functional properties of endothelium of peripheral vessels in adolescents].

In a random sample of adolescent schoolchildren (n=204) we assessed functional state of endothelium of brachial artery by test with reactive hyperemia. The data obtained was compared with values of arterial pressure and nutritional status of these adolescents and results of questionnaire survey of their parents concerning heredity and lifestyle. In 12.4% of examined subject values of flow mediated vasodilation were abnormal (less than 10%). We found that these abnormalities were most often observed in adolescents with hereditary predisposition to cardiovascular diseases, elevated arterial pressure, excess of fatty mass, inactive way of life.

[Effect of microwave on migration in the model environment of chemicals from materials that come into contact with foodstuffs].

Under the influence of microwaves is migration of chemical and metals used in manufacture for these furnaces. This confirms the need for research to develop modes of training materials used in the manufacture of utensils used in microwave ovens.

[Hygienic problems of population health maintenance under the extremal conditions of North].

A range of multi-sided studies, carried out in various regions of Far North (Jamalo-Nenets autonomous region, Komi republic, Sakha republic (Yakutia)) have established the leading hygienic risk factors of population health deterioration, including those characteristic of small nationalities of North. The consideration of the obtained data, including regional alimentary status peculiarities, the condition of metabolic processes and antioxidant balance of the organism, allowed establishment of effective approaches to the maintenance of notherners' health. These approaches are based upon the optimization of nutrition as an element of population health control under extremal conditions.

[The hygiene estimation of polyamide shells safety for the sausage products]. / Gigienicheskaia otsenka bezopasnosti poliamidnykh obolochek kolbasnykh izdelii.

The investigation of polyamide shells, contrasting according to the level of penetration and layering, named as "Amitan", "Amiflex T", "Amismok" were carried out. It was stated that in terms of technological process of cooked meats production modeling the studied polyamide shells meet the requirements of hygiene safety.

[Hygienic estimation a state of nutrition of infant and preschool children age of city of Murmansk]. / Gigienicheskaia otsenka sostoianiia pitaniia detei doshkol'nogo vozrasta Murmanska.

The present research was directed on study of an actual meal and status of nutrition of children in the age of from birth till 5 years living in Murmansk (region of Far North). 998 children were surveyed. At an estimation of an actual meal of children the data about breast feeding are received, the basic nutrients misbalance of structure of diets of children are established, and their reasons are analyzed. On the basis of the received data the regional recommendations for organization of a healthy meal in children's preschool establishments and program of hygienic training of the parents to skills of a balanced diet of children of early and junior age were developed.

[Working conditions and morbidity among workers engaged in the production of vegetable oil]. / Usloviia truda i zabolevaemost' rabotaiushchikh v proizvodstve rastitel'nogo masla.

A hygienic model for controlling some indices of their health is scientifically substantiated on the basis of the data of sanitary evaluation of working conditions and those of study of morbidity with temporary disability in workers engaged at the vegetable oil-producing enterprises. The practical use of a package of preventive and health-promoting measures caused a 7.2-30.8% reduction in the incidence of diseases with temporary disability in the workers.

[Arterial and venous fistulas of duodenal-biliary zone]. / Arterial'nye i venoznye svishchi duodenobiliarnoi zony.

Causes of gastrointestinal bleedings in patients treated from 1995 to 2001 were analyzed. Rare causes of bleeding were studied particularly. Four cases of patients hospitalized urgently for gastrointestinal bleeding are described in detail. In autopsy of these patients different variants of vascular fistulas of duodenobiliary zone were revealed: fistula of aneurysm of abdominal aorta with blood bursting into horizontal part of the duodenum (2 cases), fistula between diverticulum of proximal part of jejunum and abdominal aorta (1), choledochoportal fistula (1). Clinical and anatomical correlations differential-diagnostic difficulties were analyzed.

Hemostasis in children with dysbacteriosis in chronic constipation.

The purpose of the study was to investigate hemostasis in children with dysbacteriosis disturbance in chronic constipation. The disturbance of factors in the inner mechanism of blood coagulation (VII, IX, XI, XII) in compensated chronic constipation was defined based on the reduction in colon bacillus levels. We observed hypocoagulation caused by the reduced activity of the prothrombin complex factors, disaggregate thrombocytopathy, and endotheliosis with fibrinolysis inhibition in subcompensated chronic colostasis with continuous reduction of colon bacillus levels and pathogenic microflora appearance. In decompensated colostasis there was an increase in pathogenic microorganisms and a continuous reduction of colon bacillus levels. In hemostasis there was a factor deficiency in inner (XII, XI, IX, VIII) and outer (II, V, VII, X) blood coagulation mechanisms. Fibrinolysis inhibition, endotheliosis development with thrombocyte aggregation, and microthrombosis formation were determined. Thus, in children with chronic constipation, there was a marked reduction in the amount of colon bacillus, which led to the reproduction of pathogenic bacteria. We also observed chronometric hypocoagulation with the inner (XII, XI, IX, VIII) and outer (II, V, VII, X) mechanisms of blood coagulation, at the base of which there is the deficiency of vitamin K-dependent factors (II, VII, IX, X) and a slightly marked disturbance in the final stage of coagulation. In thrombocyte vascular hemostasis, thrombocytopathy was observed with increased adenosine-5-diphosphate aggregation and the inhibition of the inner mechanism with fibrinolysis and endotheliosis.