Agitation Effects and Kinetic Constants of Exoglucomannan Production by Antarctic Yeast Strain in a Stirred Tank Bioreactor

Exoglucomannan production by Antarctic yeast Sporobolomyces salmonicolor AL1 is studied at semi-tech scale in a 5 L stirred tank bioreactor and the bioreaction kinetics is quantified. The organism’s unconventional response to agitation is analyzed in terms of the agitation-induced mechanical stress. The yeast maximum production activity was observed at agitation rate 400 rpm and conserved or decreased at further increase in mixing intensity. Referring to the relationship of cell growth and aeration intensity, the various production activity, oxygen availability and cell growth are considered as a starting point to elucidate the possible reasons for the anomaly. At suspicion of shear detrimental effect on the yeast cells, the hydrodynamic stress acting on cell particles is determined and the microorganism morphology at low and high mixing intensity is examined. Biological stability is registered and the agitation effect is attributed to depressed metabolic activity at the evolving dissolved oxygen tension rather than to direct effect of hydrodynamics. A kinetic model is proposed. The specific growth rate (µ, h–1) and growth-associated (g EPS g–1 cells), and non-growth associated (g EPS g–1 cells h–1) production constants are determined and compared with reported estimates for similar reference EPS fermentations. The model and its parameters are determined in well-mixed cultures and could be upgraded further to account for mixing non-ideality and mass transfer in larger vessels

Comparative Evaluation of Biomechanical Characteristics of Acellular Dermal Matrix for Hernioplasty

Background. With the introduction of synthetic mesh implants into clinical practice, the recurrence rate of postoperative ventral hernias was signifi cantly reduced. The extensive use of synthetic implants led to the development of specifi c complications. The development of biological implants, based on extensively purifi ed decellularized collagen matrix of xenogeneic origin is highly relevant due to the fact that, unlike synthetic analogues, they have a biological origin and biodegrade in a natural way, gradually being replaced with newly formed connective tissue. The use of bioprostheses reduces the risk of complications.Objectives. To conduct a comparative evaluation of the biomechanical characteristics of acellular dermal matrix, obtained by detergent-enzymatic decellularization, and commercially distributed Permacol™ matrix.Methods. Acellular dermal matrix (ADM) was created by using samples of native skin of pig of Landras breed aged 4 months. The dermis was processed by means of detergent-enzymatic method. In order to evaluate and compare the mechanical properties of acellular dermal matrix, the biological samples were divided into 2 groups of 15 samples each. The fi rst group included acellular dermal matrix samples, the second group — native samples of pigs unprocessed dermis. The control group consisted of samples of PermacolTM Surgical Implant, xenotransplant for hernioplasty approved for use in the Russian Federation (Covidien, France). All samples were tested wet using universal testing instrument Instron 1122. MedCalc Statistical Software (Belgium) was used for statistical processing of the study results.Results. In the present study, pig dermis was processed using a detergent-enzymatic method to produce ADM. Routine histological examination confi rmed the removal of all cellular elements, and at the same time it was proven that the native structure of the dermis remained intact during its processing. The mechanical characteristics of xenogenic ADM were further determined. Its tensile strength was 9.1 ± 0.6 MPa (910 N/cm2 ), elongation to break was 21.1 ± 2.3%, and elastic modulus was 50.0 ± 1.6 MPa. These characteristics largely corresponded to the strength characteristics of native pig dermis and far exceeded the necessary physiological parameters. PermacolTM control was tested in two directions (longitudinal and transverse). In the longitudinal direction, the sample had higher mechanical characteristics: strength — 12.0 ± 1.7 MPa, elongation to break — 29.7 ± 2.4%, stiffness modulus — 47.2 ± 6.5 MPa. In the transverse direction, all indicators were 1.5–2 times lower.Conclusion. The developed xenogeneic biological implant in the form of ADM demonstrates rather good characteristics of plasticity, tensile strength and elasticity, to be used as a biological endoprosthesis for plasty of hernia defects of the abdominal wall of any size and shape

On the issue of obtaining platelet-rich plasma

Objective: To determine the optimal technological modes for the preparation of platelet-rich plasma (PRP) using standard laboratory equipment.Material and methods: Blood for the research was taken from 25 healthy volunteers. Its centrifugation was performed on a standard CM-6M laboratory centrifuge using various modes and two types of vacuum tubes with lithium heparin containing separation gel and without it. The number of platelets and leukocytes was calculated in the upper, lower and middle layers of the obtained plasma sample.Results: Plasma samples obtained during centrifugation modes from 415 to 1660 g for 10 minutes using test tubes that do not contain separation gel are optimal in terms of the number of platelets. Plasma intake from the lower layer of the obtained sample after centrifugation is always accompanied by the inclusion of leukocytes in its composition, which can lead to undesirable tissue reactions when it is used.Conclusion: To obtain PRP, it is possible to use standard laboratory equipment in the centrifugation mode from 415 to 1660 g for 10 minutes using test tubes that do not contain separation gel. Plasma sampling for clinical use should be carried out from the middle layer of the obtained sample

Expert Statements on the Standard of Care in Critically Ill Adult Patients With Atypical Hemolytic Uremic Syndrome.

A typical hemolytic uremic syndrome (aHUS) presents similarly to thrombotic thrombocytopenic purpura (TTP) and other causes or conditions with thrombotic microangiopathy (TMA), such as disseminated intravascular coagulation or sepsis. Similarity in clinical presentation may hinder diagnosis and optimal treatment selection in the urgent setting in the ICU. However, there is currently no consensus on the diagnosis or treatment of aHUS for ICU specialists. This review aims to summarize available data on the diagnosis and treatment strategies of aHUS in the ICU to enhance the understanding of aHUS diagnosis and outcomes in patients managed in the ICU. To this end, a review of the recent literature (January 2009-March 2016) was performed to select the most relevant articles for ICU physicians. Based on the paucity of adult aHUS cases overall and within the ICU, no specific recommendations could be formally graded for the critical care setting. However, we recognize a core set of skills required by intensivists for diagnosing and managing patients with aHUS: recognizing thrombotic microangiopathies, differentiating aHUS from related conditions, recognizing involvement of other organ systems, understanding the pathophysiology of aHUS, knowing the diagnostic workup and relevant outcomes in critically ill patients with aHUS, and knowing the standard of care for patients with aHUS based on available data and guidelines. In conclusion, managing critically ill patients with aHUS requires basic skills that, in the absence of sufficient data from patients treated within the ICU, can be gleaned from an increasingly relevant literature outside the ICU. More data on critically ill patients with aHUS are needed to validate these conclusions within the ICU setting

Prognostic and preventive role of various factors in corneal rejection after keratoplasty

The literature review is devoted to the analysis of modern publications on the immunological and pathogenetic mechanisms of transplanted corneal rejection, risk factors, predictors and methods of the prevention of this complication. The prevention of corneal rejection is challenging.Currently, there is no single algorithm for the predicting methods of the corneal graft rejection, so further research in this area is needed.Purpose. To assemble the current data on immunological and non-immunological predictors of postoperative complications after keratoplasty. The analysis of modern publications on the immunological and pathogenetic mechanisms of corneal transplant rejection, risk factors, predictors and methods of prevention of this complication is presented. The databases used were CyberLeninka, PubMed, and Medline. The focus was on the publications of the last 10 year s.Conclusion. The data presented in the review make it possible to identify signs of corneal transplant rejection and to determine treatment in a timely manner, as well as to implement methods for preventing these complications

Development of the Acellular Dermal Matrix and Experimental Substantiation of Its Use in the Anterior Abdominal Wall hernia Repair

Objective: To develop a biological implant that is an acellular dermal matrix (ADM), evaluate its use as a support material in tensionfree hernioplasty for ventral hernia, and compare it to that of the commercially available implant PermacolTM.   Materials and methods: ADM was derived from the porcine dermis (Landrace breed) decellularized using detergents and enzymes. The quality of devitalization was assessed in vitro. We performed sublay hernioplasty in 4-month-old Landrace pigs using ADM (experimental group) and PermacolTM (control group). The specimens were explanted on day 120 of the experiment for histological and immunohistochemical examination.   Results: All cellular elements were removed by the detergent-enzymatic treatment of the dermis; the native architecture of the dermis was slightly disrupted. The specimens of the commercially available chemically cross-linked biomaterial PermacolTM had better mechanical properties than ADM specimens; however, there were no significant differences in terms of cytotoxicity. The state of the tissues after the explantation (number of fibroblasts and endothelial cells) showed no differences in the result of using ADM and PermacolTM. In 120 days, the materials integrated into the tissues without the formation of adhesions or inflammation.   Conclusions: Our findings show that ADM does not have cytotoxic properties, has adequate biomechanical parameters to effectively reinforce supporting soft tissues, does not cause an inflammatory response during implantation, and integrates fully into tissues. Our study demonstrates the effectiveness and utility of the developed ADM in surgical treatment of anterior abdominal wall defects

An analysis of trends and determinants of health insurance and healthcare utilisation in the Russian population between 2000 and 2004: the 'inverse care law' in action

BACKGROUND: The break-up of the USSR brought considerable disruption to health services in Russia. The uptake of compulsory health insurance rose rapidly after its introduction in 1993. However, by 2000 coverage was still incomplete, especially amongst the disadvantaged. By this time, however, the state health service had become more stable, and the private sector was growing. This paper describes subsequent trends and determinants of healthcare insurance coverage in Russia, and its relationship with health service utilisation, as well as the role of the private sector. METHODS: Data were from the Russia Longitudinal Monitoring Survey, an annual household panel survey (2000-4) from 38 centres across the Russian Federation. Annual trends in insurance coverage were measured (2000-4). Cross-sectional multivariate analyses of the determinants of health insurance and its relationship with health care utilisation were performed in working-age people (18-59 years) using 2004 data. RESULTS: Between 2000 and 2004, coverage by the compulsory insurance scheme increased from 88% to 94% of adults; however 10% of working-age men remained uninsured. Compulsory health insurance coverage was lower amongst the poor, unemployed, unhealthy and people outside the main cities. The uninsured were less likely to seek medical help for new health problems. 3% of respondents had supplementary (private) insurance, and rising utilisation of private healthcare was greatest amongst the more educated and wealthy. CONCLUSION: Despite high population insurance coverage, a multiply disadvantaged uninsured minority remains, with low utilisation of health services. Universal insurance could therefore increase access, and potentially contribute to reducing avoidable healthcare-related mortality. Meanwhile, the socioeconomically advantaged are turning increasingly to a growing private sector

Impact of growing conditions on the gum properties of different genotypes of guar (Cyamopsis tetragonoloba (L.) Taub.)

Galactomannan (gum), a water-soluble polysaccharide, is widely used as a gelling agent in liquids, including in the oil and gas industry for hydraulic fracturing. The most effective source of this valuable plant material is seeds of guar (Cyamopsis tetragonoloba (L.) Taub.), a legume crop new for Russia. Although in recent years progress has been made in the selection of guar varieties adapted to the conditions of the Russian Federation, the question of the most appropriate region for the cultivation of this crop remains open. The purpose of the study was to investigate how a region and technology of guar cultivation can affect the main indicators of the final target product: the content and viscosity of guar gum extracted from the seeds of various guar genotypes. To understand this, ecogeographical tests of 13 guar accessions from the VIR collection were conducted at the experimental stations of the Vavilov Institute (VIR), where climatic conditions correspond to the temperature requirements of the crop. To compare the properties of gum extracted from the seeds of various genotypes, a fast-tracked laboratory method was suggested allowing gum extracts to be obtained for assessing their viscosity. The method allows fast screening of the breeding material and selecting guar genotypes with beneficial properties of guar gum which are in demand by the oil industry. Applying the fast laboratory method for assessing the properties of gum in seeds of 13 guar varieties showed that the content and viscosity of gum of the same variety vary greatly depending on growing conditions. The same set of 13 guar accessions was grown in 2018 at the Volgograd, Astrakhan, Dagestan and Kuban VIR experimental stations. As a result, the maximum viscosity values were obtained for the seeds reproduced at the Astrakhan region, where the guar was grown on irrigated lands. On the other hand, the maximum gum content in the seeds of all accessions was recorded when they were grown in the Volgograd region. The results showed that the guar gum extracted from seeds of guar plants grown in the Russian Federation can be used as a gelling agent in the processes of intensification of oil production by the method of hydraulic fracturing. This experience is new to the Russian Federation

Морфологический анализ местной тканевой реакции на подкожную имплантацию фрагментов ацеллюлярного дермального матрикса

Acellular dermal matrices (ADMs) are gaining popularity as surgical materials for operations on the pelvic organs, as well as in burn therapy and plastic surgery. Evaluation of the biocompatibility of surgical materials is an important and necessary step in the development of new ADMs.The aim of the study was to compare the results of subcutaneous implantation of ADM and native porcine skin in rats.Materials and methods. To obtain ADMs, detergent – enzymatic decellularization was used. On days 7, 14, 21, and 60 after the implantation of ADMs (the experimental group) and native porcine skin (the control group), the animals were removed from the experiment. The histologic sections were stained with hematoxylin – eosin and Masson’s trichrome stain, then an immunohistochemical reaction with antibodies to CD3 and CD68 was performed. Computer morphometry was carried out using the ImageJ software.Results. On day 7 after the implantation, moderate sterile inflammation in the experimental group and pronounced sterile inflammation with eosinophil infiltration in the control group were observed. On day 14 of the experiment, the samples from the experimental group were characterized by a relatively low content of macrophages and T-lymphocytes with insignificant edema and no signs of ADM biodegradation. The control group showed pronounced inflammation, a large number of infiltrating macrophages and T lymphocytes, as well as fragmentation of collagen fibers. On day 21 of the experiment, a thin capsule was formed around ADM, there was a small number of infiltrating T lymphocytes and macrophages, the collagen fibers of the implant were intact. In the samples of the control group, there was pronounced inflammation with the presence of a significant number of lymphocytes and macrophages, as well as fragmentation and vascularization of the implant. On day 60 of the experiment, no inflammatory response was observed around ADM, biodegradation was minimal, and a dense fibrous capsule was formed around the fragment of the native porcine skin.Conclusion. The experimental ADM has low immunogenicity and a low degree of biodegradation, which makes it possible to use it for further research to create efficient surgical material that is safe for use in clinical practice.Ацеллюлярные дермальные матриксы (АДМ) набирают большую популярность в качестве хирургических материалов при операциях на органах малого таза, в ожоговой терапии и пластической хирургии. Проверка биосовместимости материалов является важным и необходимым этапом при разработке новых АДМ.Цель исследования – провести сравнительный анализ результатов подкожной имплантации крысам АДМ и нативной дермы свиньи. Материалы и методы. Для получения АДМ использовали детергентно-энзиматический метод децеллюляризации. Через 7, 14, 21, 60 сут после имплантации АДМ (экспериментальная группа) и нативной дермы свиньи (контрольная группа) животных выводили из эксперимента. Гистологические срезы окрашивали гематоксилином и эозином, трихромом по Массону, выполняли иммуногистохимическую реакцию с антителами к CD3 и CD68. Компьютерную морфометрию проводили с помощью программы ImageJ.Результаты. На 7-е сут в экспериментальной группе отмечалось умеренное асептическое воспаление, в контрольной группе – выраженное асептическое воспаление с эозинофилами в инфильтрате. На 14-е сут в экспериментальной группе показано относительно низкое содержание макрофагов и Т-лимфоцитов с незначительным отеком, без биодеградации АДМ. В контрольной группе выявлено выраженное воспаление, инфильтрация большим количеством макрофагов и Т-лимфоцитов, а также фрагментация коллагеновых волокон. На 21-е сут вокруг АДМ сформировалась тонкая капсула, в инфильтрате малое количество Т-лимфоцитов и макрофагов, коллагеновые волокна имплантата были интактны. В образцах контрольной группы – выраженное воспаление с присутствием значительного количества лимфоцитов и макрофагов, фрагментация и васкуляризация имплантата. На 60-е сут вокруг АДМ воспалительной реакции не наблюдалось, биодеградация была минимальной, вокруг фрагмента нативной дермы свиньи сформировалась плотная фиброзная капсула.Заключение. Разработанный АДМ обладает низкой иммуногенностью и малой степенью биодеградации. Это позволяет использовать данную конструкцию для дальнейших исследований по созданию полноценного хирургического материала, безопасного для применения в клинической практике

Outcome in patients perceived as receiving excessive care across different ethical climates : a prospective study in 68 intensive care units in Europe and the USA

Whether the quality of the ethical climate in the intensive care unit (ICU) improves the identification of patients receiving excessive care and affects patient outcomes is unknown. In this prospective observational study, perceptions of excessive care (PECs) by clinicians working in 68 ICUs in Europe and the USA were collected daily during a 28-day period. The quality of the ethical climate in the ICUs was assessed via a validated questionnaire. We compared the combined endpoint (death, not at home or poor quality of life at 1 year) of patients with PECs and the time from PECs until written treatment-limitation decisions (TLDs) and death across the four climates defined via cluster analysis. Of the 4747 eligible clinicians, 2992 (63%) evaluated the ethical climate in their ICU. Of the 321 and 623 patients not admitted for monitoring only in ICUs with a good (n = 12, 18%) and poor (n = 24, 35%) climate, 36 (11%) and 74 (12%), respectively were identified with PECs by at least two clinicians. Of the 35 and 71 identified patients with an available combined endpoint, 100% (95% CI 90.0-1.00) and 85.9% (75.4-92.0) (P = 0.02) attained that endpoint. The risk of death (HR 1.88, 95% CI 1.20-2.92) or receiving a written TLD (HR 2.32, CI 1.11-4.85) in patients with PECs by at least two clinicians was higher in ICUs with a good climate than in those with a poor one. The differences between ICUs with an average climate, with (n = 12, 18%) or without (n = 20, 29%) nursing involvement at the end of life, and ICUs with a poor climate were less obvious but still in favour of the former. Enhancing the quality of the ethical climate in the ICU may improve both the identification of patients receiving excessive care and the decision-making process at the end of life