Loss Of Recovery Research Articles

A rapid analysis of Bisphenol A using MISPE coupled with HPLC-FLD in tissues of food-producing animals

Bisphenol A (BPA) is a highly-produced organic compound of anthropogenic origin with a wide-range use and is ubiquitously present in both living organisms and the environment. A previously published analytical method for testing of the free (aglycone) BPA in foodstuffs was simplified and optimized for sheep muscle tissue, kidney and liver, by using only a single MISPE purification step allied with HPLC-FLD analysis. The recovery rates and RSD values over a concentration range of 1–10 µg/kg were in the range of 67‒86% and 3‒34%, respectively, while linearity in the matrix, represented by the r2, was ≥0.999. LOD values were 0.5‒1 µg/kg and LOQ values were 1 µg/kg. The analytical method used is a contribution to the field of veterinary toxicology and food testing and also proved to be applicable for other food-producing animal species, e.g. pigs, poultry and freshwater fish. The MISPE sorbent material for testing of BPA was reusable, with up to five re-use cycles without significant loss in performance characteristics.•The paper reports on a rapid determination of free (aglycone) BPA in tissues of food-producing animals by HPLC-FLD and presents a substantial improvement of analytical performance with regard to time- and cost-savings, as well as environmental protection.•MISPE is an advanced analytical technology, and the results proved that in a single and simplified SPE step it had good performance characteristics such as selectivity, recovery and precision, allied with low LOD and LOQ values.•It was proved that MISPE BPA cartridges could be used at least five times without significant loss of methodological recovery and precision.

Deciphering glial scar after spinal cord injury.

Spinal cord injury (SCI) often leads to permanent disability, which is mainly caused by the loss of functional recovery. In this review, we aimed to investigate why the healing process is interrupted. One of the reasons for this interruption is the formation of a glial scar around the severely damaged tissue, which is usually covered by reactive glia, macrophages and fibroblasts. Aiming to clarify this issue, we summarize the latest research findings pertaining to scar formation, tissue repair, and the divergent roles of blood-derived monocytes/macrophages, ependymal cells, fibroblasts, microglia, oligodendrocyte progenitor cells (OPCs), neuron-glial antigen 2 (NG2) and astrocytes during the process of scar formation, and further analyse the contribution of these cells to scar formation. In addition, we recapitulate the development of therapeutic treatments targeting glial scar components. Altogether, we aim to present a comprehensive decoding of the glial scar and explore potential therapeutic strategies for improving functional recovery after SCI.

Muscle Strength Does Not Adapt From a Second to Third Bout of Eccentric Contractions: A Systematic Review and Meta-Analysis of the Repeated Bout Effect

Lindsay, A, Abbott, G, Ingalls, CP, and Baumann, CW. Muscle strength does not adapt from a second to third bout of eccentric contractions: A systematic review and meta-analysis of the repeated bout effect. J Strength Cond Res 35(2): 576-584, 2021-The greatest muscle strength adaptations to repeated bouts of eccentric contractions (ECC) occur after the initial injury, with little to no change in subsequent bouts. However, because of the disparity in injury models, it is unknown whether three or more bouts provide further adaptation. Therefore, we performed a systematic review of the literature to evaluate whether a third bout of skeletal muscle ECC impacts immediate strength loss and rate of strength recovery compared with a second bout. A search of the literature in Web of Science, SCOPUS, Medline, and the American College of Sports Medicine database was conducted between May and September 2019 using the keywords eccentric contraction or lengthening contraction and muscle and repeated or multiple, and bout. Eleven studies with 12 experimental groups, using 72 human subjects, 48 mice, and 11 rabbits, met the inclusion criteria. A meta-analysis using a random effects model and effect sizes (ESs; Hedges' g) calculated from the standardized mean differences was completed. Calculated ESs for immediate strength loss provided no evidence that a third bout of ECC results in greater loss of strength compared with a second bout (ES = -0.12, 95% confidence interval [CI] = -0.41 to 0.17). Furthermore, the rate of strength recovery was not different between a second and third bout (ES = -0.15, 95% CI = -1.01 to 0.70). These results indicate a third bout of skeletal muscle ECC does not improve indices of strength loss or rate of strength recovery compared with a second bout. Therefore, coaches and athletes should expect some level of persistent weakness after each of their initial training sessions involving ECC, and the faster recovery of strength deficits in the second bout documented by previous research is not different from a third bout.

АНАЛІЗ АДЕКВАТНОСТІ МОДЕЛІ ТЕХНІЧНОЇ ЕКСПЛУАТАЦІЇ СИСТЕМИ ТЕХНОЛОГІЧНОГО АВТОТРАНСПОРТУ

Технічна експлуатація кар'єрних самоскидів є важливою складовою експлуатації промислового транспорту. Рівень організації технічного обслуговування й ремонту (ТОР) системи технологічного автотранспорту (СТА) визначає ефективність транспортування гірничої маси і є умовою досягнення тривалого строку служби машин.
 Оптимальна організація ТОР можлива за умови проведення системного аналізу, розробки математичної моделі СТА, алгоритму і методики управління процесами планових впливів на кожну машину. Аналіз існуючих моделей виявив ряд недоліків, яких позбавлена створена комплексна математична модель технічної експлуатації системи технологічного автотранспорту, що визначає місце і стан кожного автосамоскида у просторах втрати, підтримання і відновлення працездатності, дозволяє описати процес експлуатації машин із урахуванням усіх технологічних та ресурсних станів техніки, переходів між ними, одночасно досягнувши мінімальних витрат на технічну експлуатацію промислового автотранспорту.
 Перед розробкою алгоритму оптимального керування та методики його запровадження, необхідно переконатися в адекватності комплексної математичної моделі та її придатності до відображення виробничих процесів на практиці.
 Виконана параметрична ідентифікація моделі, в ході якої отримана збіжність нормативних та розрахованих статистичними і чисельними методами значень параметрів СТА, котра дозволила зробити висновок, що синтезовано адекватну математичну модель технічної експлуатації системи технологічного автотранспорту, яку цілком можливо застосовувати для оптимізації її функціонування.
 Розраховані оптимальні керуючі впливи у вигляді інтенсивності планових впливів ТОР на кар'єрні самоскиди та інтенсивностей переходів зі станів планових технічних обслуговувань, ремонтів і поточного ремонту машини у стан роботи дозволяють розробити алгоритм і методику динамічного коригування параметрів ТОР кожного автосамоскида, які стануть надійним інструментарієм для створення адаптивної системи технічної експлуатації кар'єрних самоскидів.

Multi-Scale Study on Mechanical Property and Strength of New Green Sand (Poly Lactic Acid) as Replacement of Fine Aggregate in Concrete Mix

Polylactic acid (PLA) has made inroads in the commercial market segment with many unique characteristics. To list a few, such as tenacity, low flame rate, moisture regain percentage, loss of ignition percentage, combustion heat, UV resistance, elastic recovery, and higher melting point, make PLA a predominant material in the commercial market. This study is an attempt to test the feasibility of PLA’s mechanical property and strength aspects with cement mix. An article published on biodegradability aspects backed up by the essential preliminary strength and physical test results is discussed in detail in this manuscript. The work focuses on the multi-scale study along with mechanical properties and strengths to evaluate the elemental characteristics. Thermo gravimetric analysis revealed that PLA would hold inclusion into construction applications either in granular form or filament. Differential Scanning Calorimetry (DSC) found that PLA in filament form is the best inclusion material for construction applications. However, fiber’s tenacity has to be checked, as currently available filaments in the market do not have high tenacity value. From EDX(Energy-dispersive X-ray Spectroscopy) reports, 30% inclusion of PLA as a replacement for fine aggregate has constituent members as Calcium carbonate(CaCO3), Silica(SiO2), and Wollastonite (CaK) resulted in the best composition among the rest. FESEM images revealed that proper gradation in size, PLA granular form’s rough surface, or filament form would enhance the mechanical/physical behavior or even PLA’s chemical behavior.

Modeling early stage atherosclerosis in a primary human vascular microphysiological system

Novel atherosclerosis models are needed to guide clinical therapy. Here, we report an in vitro model of early atherosclerosis by fabricating and perfusing multi-layer arteriole-scale human tissue-engineered blood vessels (TEBVs) by plastic compression. TEBVs maintain mechanical strength, vasoactivity, and nitric oxide (NO) production for at least 4 weeks. Perfusion of TEBVs at a physiological shear stress with enzyme-modified low-density-lipoprotein (eLDL) with or without TNFα promotes monocyte accumulation, reduces vasoactivity, alters NO production, which leads to endothelial cell activation, monocyte accumulation, foam cell formation and expression of pro-inflammatory cytokines. Removing eLDL leads to recovery of vasoactivity, but not loss of foam cells or recovery of permeability, while pretreatment with lovastatin or the P2Y11 inhibitor NF157 reduces monocyte accumulation and blocks foam cell formation. Perfusion with blood leads to increased monocyte adhesion. This atherosclerosis model can identify the role of drugs on specific vascular functions that cannot be assessed in vivo.

Emergency right colectomy: is there a role for minimally invasive surgery?—A systematic review and meta-analysis of short-term clinical outcomes

Background: In well selected emergency settings, laparoscopic-assisted (LA) right colectomy can be safely performed with similar results to elective right colectomy in terms of intra-operative blood loss, postoperative complications and length of recovery. However, evidence is still lacking in regards to whether laparoscopy can safely replace traditional open surgery (OS) for patients needing emergency right colectomy. This systematic review and meta-analysis is aiming to present an updated evaluation of the short-term clinical outcomes of laparoscopic and open approaches for right colectomy performed in emergency settings, by analyzing safety and feasibility of the two techniques.

Improved quantification of lipid mediators in plasma and tissues by liquid chromatography tandem mass spectrometry demonstrates mouse strain specific differences

A liquid chromatography tandem mass spectrometry-based method for the quantitation of 39 lipid mediators in four sample types and in two mouse strains is described. The method builds upon existing methodologies for analysis of lipid mediators by A) utilizing a bead homogenization step for tissue samples; this eliminates the need for homogenization glassware and improves homogenization consistency, B) optimizing the isolation and purification of lipid mediators with polymeric reverse phase SPE columns with lower sorbent masses; this results in lower solvent elution volumes without loss of recovery and C) utilizing an on-column enrichment method to improve analyte focusing before chromatographic separation. The method is linear from 0.25-250 pg on column for low level lipid mediators and from 5-5000 pg on column for high level lipid mediators. The addition of a methyl formate elution step to a previously published method dramatically improved precision and recovery for the cysteinyl leukotrienes. Accuracy and precision for 4 different sample types including human plasma, mouse lung, mouse spleen and mouse liver is demonstrated. Liver samples had extremely high levels of a tentatively identified bile acid which interfered with quantitation of resolvin E1, 11B-prostaglandin F2a and thromboxane A2. Results from 2 different tissue sources from untreated mice (C57BL/6 versus BALB/c) showed dramatically different concentrations of lipid mediators.

Ocimum americanum and Lippia alba essential oils as anaesthetics for Nile tilapia: Induction, recovery of apparent unconsciousness and sensory analysis of fillets

In Brazil, humane slaughter regulations do not include fish, and hypothermia or immersion in ice water is used in most fish slaughterhouses for pre-slaughter handling. Such a method is not considered humanitarian as it does not induce an immediate loss of consciousness and fish show aversive behaviour when immersed in a water and ice mixture. This study aimed to assess the times for induction and recovery using Ocimum americanum and Lippia alba essential oils as anaesthetics in Nile tilapia, and their influence on the flavour and aroma of fillets. For the anaesthetic evaluation, Nile tilapia (224.05 ± 67.56 g, 22.10 ± 2.41 cm) were divided into four groups (40 fish/group): ethanol (ET), 2-phenoxyethanol (PE), Ocimum americanum (OA) and Lippia alba (LA), all at 500 μL/L. The times taken to reach total loss of equilibrium, anaesthesia and consciousness recovery were recorded using a stopwatch. Blood was collected from the caudal vein after 0, 1, 4, 8 and 24 h of anaesthesia for the analysis of glucose, lactate and cortisol. For the sensory analysis, fillets from fish exposed to essentials oils and hypothermia at pre-slaughter were evaluated by 122 untrained assessors to determine differences in the aroma and flavour attributes. The induction of deep anaesthesia (stage 4) was faster in the OA group (mean ± standard error of mean SEM) (126.8 ± 4.9 s), than the PE (152.3 ± 6.6 s) and LA groups (169.7 ± 10.9 s) (p < .01). A total of 91.7% (110/120) of the fish showed VOR (Vestibulo-Ocular Reflex) as the first behavioural response during consciousness recovery after anaesthesia. The levels of glucose (mmol/L) were similar amongst the groups at each time. The lactate levels (mmol/L) were higher at 0 h of sampling in LA (2.0 ± 0.2) than in ET (1.4 ± 0.8) (p < .05) and the cortisol levels (ng/mL) at 0 h were higher in ET (150.3 ± 55.3) than in OA (33.9 ± 9.7). Fillets prepared from Nile tilapia anesthetized using OA essential oil received higher sensory scores (1.5 ± 0.1) than fillets from both the Lippia alba (1.0 ± 0.1) and control groups (0.7 ± 0.1). OA and LA essential oils at 500 μL/L were effective in inducing deep anaesthesia with unconsciousness duration of 126 s, allowing time for bleeding. Anaesthesia with Ocimum americanum and Lippia alba essential oils may be indicated as an alternative to hypothermia for the pre-slaughter handling of fish in Brazil.

Promoting 3D neuronal differentiation in hydrogel for spinal cord regeneration

Spinal cord injury (SCI) affects millions of people worldwide, and results in the loss of neurons and limited recovery of functions. Bone mesenchymal stem cells (BMSCs) and neural stem cells (NSCs) can proliferate or differentiate into other specific cell types. These cells represent potential treatments for SCIs. However, recent studies have shown that NSCs mainly differentiate into astrocytes, rather than neurons, in the microenvironment of an SCI. BMSCs have been reported to promote neuronal differentiation of NSCs and reduce the formation of astrocytes. Furthermore, three-dimensional (3D) gelatin methacryloyl (GelMA) provides superior mechanical properties and functional characteristics for cell proliferation, migration, and differentiation. In this study, we proposed a functional scaffold developed by loading BMSCs and NSCs into 3D GelMA hydrogel. BMSCs and NSCs that were photo-encapsulated in the 3D GelMA hydrogel survived and demonstrated good proliferation in vitro. The NSCs differentiated more toward neurons and oligodendrocytes than toward astrocytes, a phenomenon more noticeable in low-modulus hydrogels. When functional hydrogel scaffolds, loaded with BMSCs and NSCs, were implanted into the hemisection site of the rat spinal cord, they could significantly promote motor function recovery and neuronal differentiation, and decrease glial scarring, fibrotic scarring, and inflammatory responses. The immense therapeutic potential of this system to promote axonal regeneration was thereby demonstrated. Taken together, loading of the GelMA scaffold with BMSCs and NSCs is a promising therapeutic strategy to trigger functional regeneration of the spinal cord.

Hysteresis in anesthesia and recovery: Experimental observation and dynamical mechanism

The dynamical mechanism underlying the processes of anesthesia-induced loss of consciousness and recovery is key to gaining insights into the working of the nervous system. Previous experiments revealed an asymmetry between neural signals during the anesthesia and recovery processes. Here we obtain experimental evidence for the hysteresis loop and articulate the dynamical mechanism based on percolation on multilayer complex networks with self-similarity. Model analysis reveals that, during anesthesia, the network is able to maintain its neural pathways despite the loss of a substantial fraction of the edges. A predictive and potentially testable result is that, in the forward process of anesthesia, the average shortest path and the clustering coefficient of the neural network are markedly smaller than those associated with the recovery process. This suggests that the network strives to maintain certain neurological functions by adapting to a relatively more compact structure in response to anesthesia.

Pure Endoscopic Excision of Parenchymal Brain Tumors: Feasibilty, Risks, Advantages and Realities - A Beginners Perspective

Abstract Background Neuroendoscopy is gaining popularity and is reaching new realms. Young neurosurgeons are exploring the various possibilities associated with the use of neuroendoscopy. Neuroendoscopy in excision of parenchymal brain tumors is less explored, and young neurosurgeons should be aware of the realities. The present article is an approach to put forward the difficulties faced by a young neurosurgeon and the lessons learnt. Objective To report the experience of surgical excision of parenchymal brain tumors, in selected cases, using pure endoscopic approach and to discuss its feasibility, technical benefits, risks and comparison with conventional microscopic excision. Method Eight patients of variable age group with parenchymal brain tumors were operated upon by a single surgeon and followed up for a period varying from 6 months to 2 years. Data regarding operating time, illumination, clarity of the field, size of craniotomy, blood loss and course of recovery was evaluated. All of the tumors were resected using rigid high definition zero and 30° endoscope. Results Out of eight cases, seven had lesions in the supratentorial and one in the infratentorial location. The age group ranged from 27 to 74 years old. Near to gross total resection was achieved in all except two cases. All of the patients recovered well without any significant morbidity or mortality. Hospital stay was reduced by 1 day on average. Conclusion Excision of parenchymal brain tumors via pure endoscopic method is a safe and efficient procedure. Although there is an initial period of learning curve, it is not steep for those already practicing neuroendoscopy, but the approach has its advantages.

The Role of Knee Position in Blood Loss and Enhancement of Recovery after Total Knee Arthroplasty.

The study aimed to investigate the effects of postoperative position of knee on blood loss and functional recovery after total knee arthroplasty (TKA). We enrolled patients who underwent TKA from 2017 to 2019 in our department with osteoarthritis of the knee in this prospective and randomized study. The patients were randomly allocated to flexion or extension group. In the flexion group, the affected leg was elevated by 30 degrees at the hip and the knee was flexed by 30-degree, postoperatively, while in the extension group, the affected knee was fully extended postoperatively. Patients' data related to postoperative blood loss, Hospital for Special Surgery scores, pain intensity, usage of analgesic drugs, circumference of knee, and range of motion (ROM) of knee were recorded to assess the influence of postoperative leg position on clinical outcomes. Although the transfusion rate was similar between the two groups (p > 0.05), other parameters related to blood loss (including total blood loss, hidden blood loss, usage of analgesic drugs, and postoperative circumference of knee) were significantly lower in the flexion group than those in the extension group (p < 0.05). After 6 weeks and 6 months of rehabilitation, patients gained a similar ROM in the affected knee in both groups (p > 0.05). The length of hospital stay and medical expenses were similar in both groups. Incidence of wound infection and other complications was also similar in both groups (p > 0.05). Elevation of the hip by knee flexion of 30 degrees is an effective and simple method to reduce blood loss after TKA, and contributes to reduction of the dosage of analgesic drugs in the early postoperative period. The routine application of the present protocol also did not increase medical costs and length of hospital stay after TKA.

A CFD Based Parametric Analysis of S-Shaped Inlet for a Novel Blended Wing Body Aircraft

The Advisory Council for Aeronautics Research in Europe (ACARE) has set an ambitious array of objectives to be accomplished by 2050 for civil aviation. It is often claimed that complying with those targets will not require evolution but, rather, revolution. If the growth in aviation has to be sustained in the future, then we must come up with radical aircraft and engine configurations which can meet the demands of future aviation. The AHEAD project (co-funded by the European Commission) investigated a novel multi-fuel blended wing body aircraft with a unique propulsion system to address the challenges of the future. The engine for this aircraft uses an embedded hybrid engine exploiting the boundary layer ingestion technique to increase the propulsive efficiency. Two major consequences of BLI are vital in this regard. Namely, loss of total pressure recovery and increased total pressure distortion at the Aerodynamic Interface Plane (AIP) or the engine fan-face. Hence, the inlet performance is measured by the total Pressure Recovery Factor (PRF) and Distortion Coefficient (DC60). The current research work aims to design an embedded inlet on a Blended Wing Body (BWB) aircraft that produces maximum value of PRF and minimum DC60. The aim of this research is to investigate the S-shaped inlet to understand the effect of various geometrical parameters on its performance. The Knowledge Based Engineering platform ParaPy is used to parametrize the S-shaped inlet and generate a variety of inlet geometries and volume meshes. These different variants were analysed using the Ansys® CFD code.

Monitoring of anesthetic depth and EEG band power using phase lag entropy during propofol anesthesia

BackgroundPhase lag entropy (PLE) is a novel anesthetic depth indicator that uses four-channel electroencephalography (EEG) to measure the temporal pattern diversity in the phase relationship of frequency signals in the brain. The purpose of the study was to evaluate the anesthetic depth monitoring using PLE and to evaluate the correlation between PLE and bispectral index (BIS) values during propofol anesthesia.MethodsIn thirty-five adult patients undergoing elective surgery, anesthesia was induced with propofol using target-controlled infusion (the Schneider model). We recorded the PLE value, raw EEG, BIS value, and hemodynamic data when the target effect-site concentration (Ce) of propofol reached 2, 3, 4, 5, and 6 μg/ml before intubation and 6, 5, 4, 3, 2 μg/ml after intubation and injection of muscle relaxant. We analyzed whether PLE and raw EEG data from the PLE monitor reflected the anesthetic depth as the Ce of propofol changed, and whether PLE values were comparable to BIS values.ResultsPLE values were inversely correlated to changes in propofol Ce (propofol Ce from 0 to 6.0 μg/ml, r2 = − 0.83; propofol Ce from 6.0 to 2.0 μg/ml, r2 = − 0.46). In the spectral analysis of EEG acquired from the PLE monitor, the persistence spectrogram revealed a wide distribution of power at loss of consciousness (LOC) and recovery of consciousness (ROC), with a narrow distribution during unconsciousness. The power spectrogram showed the typical pattern seen in propofol anesthesia with slow alpha frequency band oscillation. The PLE value demonstrated a strong correlation with the BIS value during the change in propofol Ce from 0 to 6.0 μg/ml (r2 = 0.84). PLE and BIS values were similar at LOC (62.3 vs. 61.8) (P > 0.05), but PLE values were smaller than BIS values at ROC (64.4 vs 75.7) (P < 0.05).ConclusionsThe PLE value is a useful anesthetic depth indicator, similar to the BIS value, during propofol anesthesia. Spectral analysis of EEG acquired from the PLE monitor demonstrated the typical patterns seen in propofol anesthesia.Trial registrationThis clinical trial was retrospectively registered at ClinicalTrials.gov at October 2017 (NCT03299621).

Olfactory Impairment in Obese Patients

Background: Recently published work and emerging research efforts have suggested that the olfactory system abilities is intimately affected by morbid obesity. Morbidly obese patients demonstrate altered olfactory acuity. High body mass index (BMI) appears to be associated with olfactory dysfunction. Increasing BMI may be a risk factor for olfactory loss or lack of olfactory recovery after an inciting event. Objective: This study aimed to discuss olfactory impairment in obese patients and to elucidate what role olfactory loss may play in diet and feeding habits of obese patients Conclusion: Our study presented a strong evidence for a causal relationship between changes in olfactory abilities of obese patients. There was altered olfactory acuityand cardiovascular, inflammatory, and cognitive declines. It was found that consumption of diets high in fat are found to cause nervous system dysfunction.

The critical degree of mineral surface oxidation in copper sulphide flotation

It is well documented that surface oxidation of copper sulphide minerals has some detrimental effects on their flotation performance. However, little work has been done to quantitatively relate surface oxidation to flotation performance, which makes it inherently difficult for processing plants to optimise flotation conditions for oxidised ores. In this study, an array of oxidised chalcopyrite and chalcocite samples was prepared and characterisation of the surface oxidation species was carried out by X-ray Photoelectron Spectroscopy (XPS). The degree of surface oxidation was quantified as the ratio of hydrophilic species to hydrophobic species and correlated with copper sulphide flotation recovery. A quantitative relationship between them was established and a critical degree of oxidation, beyond which flotation becomes impossible, was identified to be 11.7 for chalcopyrite and estimated to be in the range of 1.74–4.85 for chalcocite, indicating that chalcocite flotation is much more sensitive to surface oxidation. This study will enable provision of guidelines to better manage oxidised copper ores to circumvent the loss of recovery and will also help in developing potential solutions that could be applied to flotation of minerals with different degrees of oxidation.

Comparison of the Effect of Nitroglycerin, Magnesium Sulphate and Dexmedetomidine as Hypotensive Agents in Lumbar Spine Surgery

Background: in orthopedic procedures more blood is lost from raw bone and muscle surface than from identifiable blood vessels. Moderate hypotensive anesthesia was found to significantly decrease the average blood loss by nearly 40%, reduce the need for transfusion by 45% and shorten the average operating time by nearly 10%. Objective: The aim of the current study was to compare magnesium sulphate and dexmedetomidine with nitroglycerin as regard hypotensive effect as primary outcome, volume of blood loss, blood substitution and pattern of recovery as secondary outcome during lumbar spine surgery. Patients and Methods: This prospective, controlled, comperative, randomized, double blind study included a total of ninty patients aged 21-50 years of both sex, ASA I-II scheduled for elective lumber spine surgery, attending at Department of Orthopedic, AL-Azher university Hospital in Assuit as single center study. Patients have received either dexmedetomidine, magnesium sulfate or nitroglycerine. Results: There were highly significant difference (P <0.000) with duration of surgery between different study groups with duration of surgery shortest in dexmedetomidine group followed by magnesium sulfate group and then nitroglycerine group. There were highly significant differences between different study groups with fluid maintenance with higher volume in nitroglycerine group then magnesium sulfate group and then dexmedetomidine group. There were highly significant differences (P <0.000) with systolic blood pressure between study groups at A1 and hypotensive agent discontinuation with lowest systolic blood pressure in dexmedetomidine group followed by magnesium sulfate group and then nitroglycerine group. Conclusion: nitroglycerine, magnesium sulfate and dexmedetomidine could induce hypotension, but dexmedetomidine showed more favorable hemodynamic profile as regard blood pressure and heart rate.

Abstract 1294: Differential sigma-2 receptor-mediated metabolic stimulative and apoptotic effects of monovalent CM571 and its homo-bivalent counterpart, MAM03055A

Abstract Sigma-2 receptors, recently identified as TMEM97, are highly expressed in various types of cancer cells. Sigma-2 receptor agonists have traditionally been characterized as ligands that induce programmed cell death in various cancer cell types. Sigma-2 receptor-mediated cell death involves a number of mechanisms including caspase activation, mitochondrial depolarization, and autophagy. Recently, we reported a novel metabolically stimulative function of the sigma-2 receptor with stimulation of glycolytic hallmarks, including increase in cellular ATP level, reduced ROS, and stabilization of HIF-1α. We have investigated a family of 6-substituted analogs of the canonical sigma-2 receptor antagonist, SN79, members of which can produce both the metabolic stimulative and the cytotoxic effects. Here we compare the activities of two closely related compounds. CM571, the 6-amino derivative, bound with high affinity to both sigma-1 and sigma-2 receptors (sigma-1 Ki = 15.5 nM; sigma-2 Ki = 21.7 nM). MAM03055A (MAM) is essentially a homo-bivalent dimer of CM571, linked by a thiourea moiety. MAM exhibited high affinity and selectivity for sigma-2 receptors (sigma-1 Ki = 3,371 nM; sigma-2 Ki = 55.9 nM). The functional effects of the two compounds were compared in human SK-N-SH neuroblastoma cells. CM571 caused a dose-dependent stimulation of MTT reduction, indicating the metabolic stimulative-effect, producing 40% stimulation at 30 µM. By contrast, MAM induced dose-dependent cell death with an EC50 = 4.24 µM. MAM induced time-dependent cleavage of proapoptotic Bid, a key component of the programmed cell death mechanism of sigma-2 ligands in these cells. Previous studies had shown that only irreversibly binding, isothiocyanate analogs of SN79 induced programmed cell death, while other analogs produced metabolic stimulation. Rat liver membranes were treated with compound, washed to remove unbound ligand, and then subjected to radioligand binding to determine recovery of sigma-1 receptors ([3H](+)-pentazocine) and sigma-2 receptors ([3H]DTG + (+)-pentazocine). Treatment with CM571 resulted in full recovery of both sigma-1 and sigma-2 binding. However, MAM treatment resulted in loss of sigma-2 binding and full recovery of sigma-1 activity, indicating irreversible binding to the sigma-2 receptor. Since there is no chemically reactive moiety in MAM to react covalently, MAM binds “pseudo-irreversibly”. Treatment of cells with MAM for 60 min, followed by washout produced nearly comparable levels of cell death 24 h later as continuous exposure of cells for 24 hours, consistent with pseudo-irreversible action at the sigma-2 receptor. The results show that mono-valent and bivalent sigma-2 ligands in this series show different modes of interaction with the receptor, resulting in divergent effects on cell viability. Citation Format: Cheri Z. Liu, Bridget M. McVeigh, Marco Mottinelli, Hilary E. Nicholson, Christopher R. McCurdy, Wayne D. Bowen. Differential sigma-2 receptor-mediated metabolic stimulative and apoptotic effects of monovalent CM571 and its homo-bivalent counterpart, MAM03055A [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1294.

A Novel Modulation Strategy With Unconditional Neutral Point Voltage Balance and Three Switching Actions in One Switching Cycle for Neutral Point Clamped Three-Level Converter

The carrier-based pulsewidth modulation (CBPWM) and virtual space vector pulsewidth modulation (VSVPWM) for neutral point clamped three-level converter are reviewed briefly in this paper. A novel modulation strategy is proposed to maintain unconditional neutral point voltage balance under the full range of power factor and modulation index. The proposed PWM strategy is featured with three switching actions in one switching cycle, which is named 3SNPBPWM hereafter. In 3SNPBPWM, one phase is clamped to a certain level without switching action, and the other two phases have one and two switching actions in one switching cycle (SC), respectively. Moreover, a neutral point voltage recovery algorithm for 3SNPBPWM is also proposed. The performance of 3SNPBPWM is analyzed and compared with CBPWM and VSVPWM in terms of switching loss, waveform quality, and ability of neutral point voltage recovery. Finally, the feasibility and superiority of 3SNPBPWM are verified by experiment.