Neurotoxicity of general anesthetics: A modern view of the problem

All general anesthetics routinely used in clinical practice are noted to have a neurotoxic effect on the brain in different animal species including primates. The negative effects observed both in young and sexually mature animals include apoptotic neuronal cell death, suppression of neurogenesis and gliogenesis, neuroinflammation, as well as learning and memory impairments. A number of epidemiologic surveys have established an association between anesthesia in patients younger than 3 to 4 years and subsequent learning disabilities and language disorders whereas others have not found this link. In middle-aged and elderly patients, anesthesia is frequently associated with the development of postoperative cognitive dysfunction. The key component of its pathogenesis (general anesthesia itself or other factors, such as operative injury, an inflammatory response, pain syndrome, intraoperative complications, underlying disease in a patient) remains unelucidated. It is concluded that there is a need for additional experimental and clinical studies of the pathogenesis of these undesirable phenomena to be prevented and corrected

Using the third state of matter: high harmonic generation from liquid targets

High harmonic generation on solid and gaseous targets has been proven to be a powerful platform for the generation of attosecond pulses. Here we demonstrate a novel technique for the XUV generation on a smooth liquid surface target in vacuum, which circumvents the problem of low repetition rate and limited shot numbers associated with solid targets, while it maintains some of its merits. We employed atomically smooth, continuous liquid jets of water, aqueous salt solutions and ethanol that allow uninterrupted high harmonic generation due to the coherent wake emission mechanism for over 8 h. It has been found that the mechanism of plasma generation is very similar to that for smooth solid target surfaces. The vapor pressure around the liquid target in our setup has been found to be very low such that the presence of the gas phase around the liquid jet could be neglected

Postoperative encephalopathy: Pathophysiological and morphological bases of its prevention under general anesthesia

In vitro and in vivo studies have provided sufficient evidence of the neurotoxicity of general anesthetics and their ability to cause postoperative cognitive dysfunction (POCD). The latter is one of the undesirable phenomena associated with general anesthesia. Recently, the prevention of postoperative cognitive impairments has been of particular relevance because of their high incidence, longer length of hospital stay, higher cost of treatment, worse quality of life in patients, and no approaches to drug correction and prevention. The review gives data on the negative effects of general anesthesia in patients of different age groups, highlights the pathogenetic mechanisms of POCD, and proposes its possible drug prevention and treatment strategies: identification of patients at high risk for POCD and both pre- and postoperative neuropsychological testing; intraoperative POCD prevention using a package of measures and, if inefficient, drug correction of found cognitive impairments just in the early postoperative period

Влияние ультразвуковых колебаний на величину сил резания в процессе алмазной доводки ювелирных камней

An influence of ultrasound vibrations initiated in a tool on decrease of cutting forces in the process of abrasive machining of jewel specimens has been investigated. The paper contains description of an pilot unit, a tool design and methodology of investigations. Mechanism of contact interaction due to ultrasound vibrations is described in the paper. Quantitative evaluation of decrease in cutting forces acting in the finishing zone and influence of acoustic and technological factors on the rate of decrease in these forces are given and determined in the paper.Исследовано влияние ультразвуковых колебаний, возбуждаемых в инструменте, на снижение сил резания в процессе абразивной обработки образцов ювелирных камней. Приведены описание экспериментальной установки, конструктивное исполнение инструмента и методика исследований. Описан механизм контактного взаимодействия при воздействии ультразвуковых колебаний; приведена количественная оценка снижения сил резания, действующих в зоне обработки; установлено влияние акустических и технологических факторов на степень снижения этих сил

Экспериментальная оценка влияния ультразвука на производительность и качество алмазной доводки хрупких материалов

The paper gives main principles of the methodology for execution of experimental investigations with the help of principally newly designed ultrasound machine-tool with acoustic system which is set in the spindle unit. Treatment of a number of semi-precious stones and mono-crystals by diamond tools of various graininess has revealed dominating technological factors that influence on quantitative and qualitative process indice. Mechanisms of inter-relation of a lapping disk and a treated piece with directed action of ultrasound oscillation are given in the paper. The obtained results testify efficiency of ultrasound application for treatment of hard and fragile materials (crystals).Приводятся основные положения методики проведения экспериментальных исследований на принципиально новой конструкции ультразвукового станка с акустической системой в шпиндельном узле. В результате обработки ряда поделочных камней и монокристаллов алмазоносными инструментами различной зернистости получены результаты, которые выявили доминирующие технологические факторы, влияющие на количественные и качественные показатели процесса. Даны механизмы взаимодействия диска-притира и обрабатываемого изделия при направленном действии ультразвуковых колебаний. Результаты свидетельствуют об эффективности использования ультразвука при обработке твердых и хрупких материалов (кристаллов)

Synthetic Analogue of Leu-Enkephalin Prevents Endothelial Dysfunction in vitro

The purpose of the study was to determine the efficacy of a synthetic leu-enkephalin stabilized analogue to prevent damage of endothelial cells monolayer in vitro caused by serum samples from septic shock patients.Materials and methods. The experiments were performed using the EaHy.926 endothelial cells monolayer. We studied the in vitro effect of synthetic leu-enkephalin analogue on the cell damage caused by serum samples from five septic shock patients. The status of endothelial intercellular junctions was estimated by immunofluorescence microscopy and western blot with antibodies against adherens junction protein, VE-cadherin, and against the tight junctions protein, claudin. Cell viability was determined by staining with propidium iodide.Results. Preconditioning with a synthetic leu-enkephalin analogue (10, 50 and 100 μg/ml) of endothelial cells in vitro prevented the destruction of both tight and adherens junction and partially prevented endothelial cell death.Conclusion. Preconditioning with a synthetic leu-enkephalin analogue partially prevents endothelial cell damage caused by exposure to septic patients’ sera in vitro. These data ensure the need for clinical trials on the effectiveness of a synthetic leu-enkephalin analogue for prevention of sepsis-associated endothelial dysfunction in clinics

Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications

BACKGROUND Limited information exists about the epidemiology and outcome of surgical patients at increased risk of postoperative pulmonary complications (PPCs), and how intraoperative ventilation was managed in these patients. OBJECTIVES To determine the incidence of surgical patients at increased risk of PPCs, and to compare the intraoperative ventilation management and postoperative outcomes with patients at low risk of PPCs. DESIGN This was a prospective international 1-week observational study using the ‘Assess Respiratory Risk in Surgical Patients in Catalonia risk score’ (ARISCAT score) for PPC for risk stratification. PATIENTS AND SETTING Adult patients requiring intraoperative ventilation during general anaesthesia for surgery in 146 hospitals across 29 countries. MAIN OUTCOME MEASURES The primary outcome was the incidence of patients at increased risk of PPCs based on the ARISCAT score. Secondary outcomes included intraoperative ventilatory management and clinical outcomes. RESULTS A total of 9864 patients fulfilled the inclusion criteria. The incidence of patients at increased risk was 28.4%. The most frequently chosen tidal volume (VT) size was 500 ml, or 7 to 9 ml kg1 predicted body weight, slightly lower in patients at increased risk of PPCs. Levels of positive end-expiratory pressure (PEEP) were slightly higher in patients at increased risk of PPCs, with 14.3% receiving more than 5 cmH2O PEEP compared with 7.6% in patients at low risk of PPCs (P < 0.001). Patients with a predicted preoperative increased risk of PPCs developed PPCs more frequently: 19 versus 7%, relative risk (RR) 3.16 (95% confidence interval 2.76 to 3.61), P < 0.001) and had longer hospital stays. The only ventilatory factor associated with the occurrence of PPCs was the peak pressure. CONCLUSION The incidence of patients with a predicted increased risk of PPCs is high. A large proportion of patients receive high VT and low PEEP levels. PPCs occur frequently in patients at increased risk, with worse clinical outcome

Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications: LAS VEGAS - An observational study in 29 countries

BACKGROUND Limited information exists about the epidemiology and outcome of surgical patients at increased risk of postoperative pulmonary complications (PPCs), and how intraoperative ventilation was managed in these patients. OBJECTIVES To determine the incidence of surgical patients at increased risk of PPCs, and to compare the intraoperative ventilation management and postoperative outcomes with patients at low risk of PPCs. DESIGN This was a prospective international 1-week observational study using the ‘Assess Respiratory Risk in Surgical Patients in Catalonia risk score’ (ARISCAT score) for PPC for risk stratification. PATIENTS AND SETTING Adult patients requiring intraoperative ventilation during general anaesthesia for surgery in 146 hospitals across 29 countries. MAIN OUTCOME MEASURES The primary outcome was the incidence of patients at increased risk of PPCs based on the ARISCAT score. Secondary outcomes included intraoperative ventilatory management and clinical outcomes. RESULTS A total of 9864 patients fulfilled the inclusion criteria. The incidence of patients at increased risk was 28.4%. The most frequently chosen tidal volume (V T) size was 500 ml, or 7 to 9 ml kg−1 predicted body weight, slightly lower in patients at increased risk of PPCs. Levels of positive end-expiratory pressure (PEEP) were slightly higher in patients at increased risk of PPCs, with 14.3% receiving more than 5 cmH2O PEEP compared with 7.6% in patients at low risk of PPCs (P ˂ 0.001). Patients with a predicted preoperative increased risk of PPCs developed PPCs more frequently: 19 versus 7%, relative risk (RR) 3.16 (95% confidence interval 2.76 to 3.61), P ˂ 0.001) and had longer hospital stays. The only ventilatory factor associated with the occurrence of PPCs was the peak pressure. CONCLUSION The incidence of patients with a predicted increased risk of PPCs is high. A large proportion of patients receive high V T and low PEEP levels. PPCs occur frequently in patients at increased risk, with worse clinical outcome.</p