Compatibility and stability of an admixture of multiple anaesthetic drugs for opioid-free anaesthesia.

The ability to combine and use drugs in a single infusion device may be useful in resource-limited settings. This study examined the chemical stability of an opioid-sparing mixture of ketamine, lidocaine and magnesium sulphate when combined in a single syringe. High-performance liquid chromatography and atomic absorption spectrophotometry were performed on six syringes containing the three-drug mixture. Since most opioid-sparing techniques typically rely on a 24-hour infusion regime, we tested stability at the initial admixing and 24 hours later. Stability was defined as a measured drug concentration within 10% of expected, with the absence of precipitation or pH alterations. Pharmacokinetic simulations were conducted to further show that the achieved plasma drug concentrations were well within an effective analgesic range. All mixed drug concentration measurements were within the required 10% reference limit. No obvious precipitation or interaction occurred, and pH remained stable. Drug stability was maintained for 24 hours. Pharmacokinetic simulations showed that ketamine and lidocaine were within their minimum analgesic effect concentrations. Our results show that this three-drug mixture is chemically stable for up to 24 hours after mixing, with a pharmacokinetic simulation illustrating safe, clinically useful predicted plasma concentrations when using the described admixture.

The effect of magnesium added to bupivacaine for arthroscopy: a meta-analysis of randomized controlled trials.

INTRODUCTION: The analgesic efficacy of magnesium sulphate added to bupivacaine for arthroscopy remains controversial. We conduct a systematic review and meta-analysis to explore the efficacy of magnesium sulphate in combination with bupivacaine for arthroscopy. METHODS: We searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through July 2020 for randomized controlled trials (RCTs) assessing the effect of magnesium sulphate plus bupivacaine versus bupivacaine for arthroscopy. This meta-analysis is performed using the random-effect model. RESULTS: Six RCTs were included in the meta-analysis. Overall, compared with bupivacaine for arthroscopy, combination analgesia using magnesium plus bupivacaine was associated with significantly prolonged duration of analgesia (SMD=0.93; 95% CI=0.27 to 1.60; P=0.006) and first time to analgesic requirement (SMD=196.57; 95% CI=13.90 to 379.24; P=0.03), reduced pain scores (SMD=-1.71; 95% CI=-2.96 to -0.46; P=0.007) and analgesic consumption (SMD=-1.04; 95% CI=-1.49 to -0.60; P<0.00001), but showed no remarkable influence on nausea or vomiting (OR=1.54; 95% CI=0.60 to 3.97; P=0.37). CONCLUSIONS: Magnesium sulphate added to bupivacaine may significantly improve the analgesic efficacy for arthroscopy.

Structural responses of model biomembranes to Mars-relevant salts.

Lipid membranes are a key component of contemporary living systems and are thought to have been essential to the origin of life. Most research on membranes has focused on situations restricted to ambient physiological or benchtop conditions. However, the influence of more extreme conditions, such as the deep subsurface on Earth or extraterrestrial environments are less well understood. The deep subsurface environments of Mars, for instance, may harbor high concentrations of chaotropic salts in brines, yet we know little about how these conditions would influence the habitability of such environments for cellular life. Here, we investigated the combined effects of high concentrations of salts, including sodium and magnesium perchlorate and sulfate, and high hydrostatic pressure on the stability and structure of model biomembranes of varying complexity. To this end, a variety of biophysical techniques have been applied, which include calorimetry, fluorescence spectroscopies, small-angle X-ray scattering, dynamic light scattering, and microscopy techniques. We show that the structure and phase behavior of lipid membranes is sensitively dictated by the nature of the salt, in particular its anion and its concentration. We demonstrate that, with the exception of magnesium perchlorate, which can also induce cubic lipid arrangements, long-chain saturated lipid bilayer structures can still persist at high salt concentrations across a range of pressures. The lateral organization of complex heterogeneous raft-like membranes is affected by all salts. For simple, in particular bacterial membrane-type bilayer systems with unsaturated chains, vesicular structures are still stable at Martian brine conditions, also up to the kbar pressure range, demonstrating the potential compatibility of environments containing such ionic and pressure extremes to lipid-encapsulated life.

Non-clinical safety profile and pharmacodynamics of two formulations of the anti-sepsis drug candidate Rejuveinix (RJX).

Here, we demonstrate that the two distinct formulations of our anti-sepsis drug candidate Rejuveinix (RJX), have a very favorable safety profile in Wistar Albino rats at dose levels comparable to the projected clinical dose levels. 14-day treatment with RJX-P (RJX PPP.18.1051) or RJX-B (RJX-B200702-CLN) similarly elevated the day 15 tissue levels of the antioxidant enzyme superoxide dismutase (SOD) as well as ascorbic acid in both the lungs and liver in a dose-dependent fashion. The activity of SOD and ascorbic acid levels were significantly higher in tissues of RJX-P or RJX-B treated rats than vehicle-treated control rats (p < 0.0001). There was no statistically significant difference between tissue SOD activity or ascorbic acid levels of rats treated with RJX-P vs. rats treated with RJX-B (p > 0.05). The observed elevations of the SOD and ascorbic acid levels were transient and were no longer detectable on day 28 following a 14-day recovery period. These results demonstrate that RJX-P and RJX-B are bioequivalent relative to their pharmacodynamic effects on tissue SOD and ascorbic acid levels. Furthermore, both formulations showed profound protective activity in a mouse model of sepsis. In agreement with the PD evaluations in rats and their proposed mechanism of action, both RJX-P and RJX-B exhibited near-identical potent and dose-dependent anti-oxidant and anti-inflammatory activity in the LPS-GalN model of ARDS and multi-organ failure in mice.

Effect of Hofmeister Ions on Transport Properties of Aqueous Solutions of Sodium Hyaluronate.

Tracer diffusion coefficients obtained from the Taylor dispersion technique at 25.0 °C were measured to study the influence of sodium, ammonium and magnesium salts at 0.01 and 0.1 mol dm-3 on the transport behavior of sodium hyaluronate (NaHy, 0.1%). The selection of these salts was based on their position in Hofmeister series, which describe the specific influence of different ions (cations and anions) on some physicochemical properties of a system that can be interpreted as a salting-in or salting-out effect. In our case, in general, an increase in the ionic strength (i.e., concentrations at 0.01 mol dm-3) led to a significant decrease in the limiting diffusion coefficient of the NaHy 0.1%, indicating, in those circumstances, the presence of salting-in effects. However, the opposite effect (salting-out) was verified with the increase in concentration of some salts, mainly for NH4SCN at 0.1 mol dm-3. In this particular salt, the cation is weakly hydrated and, consequently, its presence does not favor interactions between NaHy and water molecules, promoting, in those circumstances, less resistance to the movement of NaHy and thus to the increase of its diffusion (19%). These data, complemented by viscosity measurements, permit us to have a better understanding about the effect of these salts on the transport behaviour of NaHy.

Enhancement of ß-Mannanase Production by Bacillus subtilis ATCC11774 through Optimization of Medium Composition.

Palm kernel cake (PKC) has been largely produced in Malaysia as one of the cheap and abundant agro-waste by-products from the palm oil industry and it contains high fiber (mannan) content. The present study aimed to produce ß-mannanase by Bacillus subtilis ATCC11774 via optimization of the medium composition using palm kernel cake as substrate in semi-solid fermentation. The fermentation nutrients such as PKC, peptone, yeast extract, sodium chloride, magnesium sulphate (MgSO2), initial culture pH and temperature were screened using a Plackett-Burman design. The three most significant factors identified, PKC, peptone and NaCl, were further optimized using central composite design (CCD), a response surface methodology (RSM) approach, where yeast extract and MgSO2 were fixed as a constant factor. The maximum ß-mannanase activity predicted by CCD under the optimum medium composition of 16.50 g/L PKC, 19.59 g/L peptone, 3.00 g/L yeast extract, 2.72 g/L NaCl and 0.2 g/L MgSO2 was 799 U/mL. The validated ß-mannanase activity was 805.12 U/mL, which was close to the predicted ß-mannanas activity. As a comparison, commercial media such as nutrient broth, M9 and Luria bertani were used for the production of ß-mannanase with activities achieved at 204.16 ± 9.21 U/mL, 50.32 U/mL and 88.90 U/mL, respectively. The optimized PKC fermentation medium was four times higher than nutrient broth. Hence, it could be a potential fermentation substrate for the production of ß-mannanase activity by Bacillus subtilis ATCC11774.

The Quality of Ciders Depends on the Must Supplementation with Mineral Salts.

Providing yeast with the right amount of mineral salts before fermentation can contribute to improving the entire technological process, resulting in a better-quality final product. The aim of this study was to assess the impact of apple must supplementation with mineral salts ((NH4)2SO4, MgSO4, (NH4)3PO4)) on enological parameters, antioxidant activity, total polyphenol content, and the profile of volatile cider compounds fermented with various yeast strains. Rubin cultivar must was inoculated with wine, cider, and distillery or wild yeast strains. Various mineral salts and their mixtures were introduced into the must in doses from 0.167 g/L to 0.5 g/L. The control sample consisted of ciders with no added mineral salts. The basic enological parameters, antioxidant properties, total polyphenol content, and their profile, as well as the composition of volatile compounds, were assessed in ciders. Must supplementation with magnesium salts significantly influenced the use of the analyzed element by yeast cells and was dependent on the yeast strain. In supplemented samples, a decrease in alcohol concentration and total acidity, as well as an increase in the content of extract and total polyphenols, was observed compared to the controls. The addition of ammonium salts caused a decrease in the amount of higher alcohols and magnesium salts, as well as a decrease in the concentration of some esters in ciders.

Influence of magnetic field on extraction of model proteins in polyethylene glycol/magnesium sulfate aqueous two-phase system.

Separation of molecules in aqueous two-phase systems (ATPS) depends on many factors, e.g. salt concentration, pH, polyethylene glycol (PEG) concentration and molecular weight. The aim of the study was to analyze partition of model proteins (lysozyme, bovine serum albumin and hemoglobin) depending on the magnetic field action and the factors mentioned above in PEG/MgSO4 ATPS. Partition of these proteins studied always depended on PEG molecular weight, while salt concentration influenced only BSA and HGB separation. Two of the proteins tested, i.e. lysozyme and BSA showed high affinity to the PEG-rich-phase. The magnetic field significantly forced distribution of BSA and lysozyme to the phase rich in MgSO4. Hemoglobin, which presented a tendency to accumulation in salt phase was not affected by the magnetic field. Thus, the influence of the magnetic field on protein partition in ATPS is a consequence of the properties of separated molecules, and rearranges of water dipoles and hydrogen bonds reshape.

Mechanistic insights on immobilization and decontamination of hexavalent chromium onto nano MgS/FeS doped cellulose nanofibres.

Sustainable bio nano composite comprising of nanoMgS/FeS doped cellulose nanofibres (FeMgSCNF) was prepared, characterized by various techniques and assessed for the decontamination of Cr(VI). Cellulose nanofibres (CNF) acts as a template and stabilizer and prevents agglomeration of FeS/MgS nano particles. MgS present in the nano-composite provides a barrier to suppress aerial oxidation of Fe(II) and provided additional source of sulfide ions. An adsorption capacity in the order of 142.8 mg/g of the bionano composite was exhibited towards hexavalent chromium. Both FeSCNF and FeMgSCNF followed pseudo first order and pseudo second order kinetics with regression coefficients >0.96. X-ray photoelectron spectroscopy (XPS) studies indicated that decontamination of Cr(VI) follows the route of electrostatic attraction, ion-exchange followed by reduction of Cr(VI) to Cr(III) and immobilization of Cr(III) as chromic oxide and Fe-Cr mixed oxide. Toxicity characteristics leaching tests revealed the efficacy of immobilization. Finally the developed sorbents were successfully applied to the removal of chromium from tannery waste effluents.

Determination of the Solution Structure of Antifreeze Glycoproteins Using Two-Dimensional Infrared Spectroscopy.

We study the solution structure of antifreeze glycoproteins (AFGPs) with linear and two-dimensional infrared spectroscopy (2D-IR). With 2D-IR, we study the coupling between the amide I and amide II vibrations of AFGPs. The measured nonlinear spectral response constitutes a much more clearly resolved amide I spectrum than the linear absorption spectrum of the amide I vibrations and allows us to identify the different structural elements of AFGPs in solution. We find clear evidence for the presence of polyproline II (PPII) helical structures already at room temperature, and we find that the fraction of PPII structures increases when the temperature is decreased to the biological working temperature of AFGP. We observe that inhibition of the antifreeze activity of AFGP using borate buffer or enhancing the antifreeze activity using sulfate buffer does not lead to significant changes in the protein conformation. This finding indicates that AFGPs bind to ice with their sugar side chains.

Biomass waste-derived nitrogen-rich hierarchical porous carbon offering superior capacitive behavior in an environmentally friendly aqueous MgSO4 electrolyte.

Nitrogen-doped porous carbons have been extensively investigated to improve the specific capacitance in aqueous electrolytes by increasing the specific surface area and nitrogen content and by optimizing the pore structure. However, research on the effect of electrolyte cations on the specific capacitance of these materials is rare, especially for neutral electrolytes. Herein, a nitrogen-rich hierarchically porous carbon (NRHPC) with a high nitrogen content of 12.3 atm% is successfully prepared by pyrolyzing a mixture of bagasse, K2CO3 and urea in a mass ratio of 2:1:4. It is found that NRHPC shows superior electrochemical performance in MgSO4 than in Li2SO4 electrolyte, with specific capacitances of 315.0, 274.4, and 188.1 F g-1 at 1.0, 10.0, and 100 A g-1, respectively. Furthermore, it is found that the capacitance enhancement is closely related to the nitrogen content of the porous carbon materials. Theoretical calculation reveals that the Mg2+ ions have higher affinity towards the N atoms than Li+, producing higher charge storage capability via interaction between the Mg2+ and N atoms. When the 1.0 M MgSO4 is used as electrolyte, a symmetric capacitor based on the nitrogen-rich hierarchically porous carbon shows a high energy density of 39.5 Wh kg-1 at a power density of 0.9 kW kg-1. Moreover, this as-assembled device displays superior long-term cycling stability, with a capacitance retention of >96.2% after 10,000 cycles at 10.0 A g-1.

Control of Aliivibrio fischeri Luminescence and Decrease in Bioluminescence by Fungicides.

Studies have reported that cell density, ultraviolet (UV) irradiation, and redox reactions, can induce bioluminescence in bacteria. Conversely, the relationship between seawater components and luminescence is not well understood. The efficacy of marine luminous bacteria as biosensors, and their reactivity to fungicides (for example postharvest pesticides) are also unknown. Therefore, we studied the relationship between the luminescence of Aliivibrio fischeri and the composition of artificial seawater media and analyzed the toxicity of fungicides using A. fischeri grown only with the elements essential to induce luminescence. Luminescence was activated in the presence of KCl, NaHCO3, and MgSO4. In addition, we cultivated A. fischeri with other compounds, including K+, HCO3-, and SO42- ions. These results suggested that A. fischeri requires K+, HCO3-, and SO42- ions to activate cell density-independent luminescence. Additionally, A. fischeri cultured in 2.81% NaCl solutions containing KCl, NaHCO3, and MgSO4 exhibited a decrease in luminescence in the presence of sodium orthophenylphenol at >10 ppm. This result suggests that A. fischeri can be used as a biosensor to detect the presence of sodium ortho-phenylphenol.

Evaluation of lipid peroxidation and the level of some elements in rat erythrocytes during separate and combined vanadium and magnesium administration.

The impact of vanadium (V) and magnesium (Mg) as sodium metavanadate (SMV, 0.125 mg V/ml) and magnesium sulfate (MS, 0.06 mg Mg/ml) on lipid peroxidation (LPO) and selected elements in the rat erythrocytes (RBCs) was investigated. Relationships between some indices determined in RBC were also studied. SMV alone (Group II) elevated the malondialdehyde level (MDARBC) (by 95% and 60%), compared with the control (Group I) and MS-supplemented rats (Group III), respectively, reduced the concentration of CuRBC (by 23.5%), in comparison with Group I, but did not change the levels of NaRBC, KRBC, and CaRBC, whereas MS alone (Group III) only reduced the CuRBC concentration (by 22%), compared with Group I. The SMV + MS combination (Group IV) reduced and elevated the CuRBC (by 24%) and CaRBC (by 111%) concentrations, respectively, in comparison with Groups I and III, and these changes were induced by the V-Mg antagonistic and synergistic interaction, respectively. The combined SMV + MS effect also enhanced the MDARBC level, compared with Groups I (by 79%) and III (by 47%) and slightly limited its concentration, compared with Group II, which, in turn, resulted from the distinct trend toward the V-Mg antagonistic interaction. We can conclude that V (as SMV) is able to stimulate LPO in rat RBCs and that V-Mg interactive effects are involved in changes in CuRBC, CaRBC, and MDARBC. Further studies are needed to elucidate the exact mechanisms of the V-Mg antagonistic/synergistic interactions and to provide insight into the biochemical mechanisms of changes in rats suffering from anemia [1], characterized by a disrupted antioxidant barrier in RBCs [2] and an intensified free radical process in these cells.

Safety Assessment of Magnesium Sulfate as Used in Cosmetics.

The Cosmetic Ingredient Review Expert Panel (Panel) reviewed the safety of magnesium sulfate, which functions as a bulking agent in cosmetic products and is reportedly used at concentrations up to 11% and 25% in leave-on and rinse-off products, respectively. The Panel noted that the history of safe medical use of magnesium sulfate provides further confidence that there are no significant toxicity concerns relating to systemic exposure to this ingredient after cosmetic product application. Furthermore, the extensive clinical experience of the Panel, including the results of numerous patch tests, indicates that magnesium salts do not have the potential to induce sensitization. The Panel also noted that results were negative for 50% magnesium sulfate in a mouse skin irritation study and in an in vitro sensitization assay. The Panel concluded that magnesium sulfate is safe in cosmetics in the present practices of use and concentration described in the safety assessment.

Separation of transglutaminase using aqueous two-phase systems composed of two pH-response polymers.

Aqueous two-phase systems (ATPS) have been effectively used as a rapid and economical method for the separation and purification of many enzymes or proteins. However, a key problem is the recovery of the polymers forming ATPS and there are rarely available studies about ATPS for the transglutaminase. In this study, a pH-responsive ATPS has been established by two pH-responsive polymers (PADB4.91 and PADB4.06) that can be recycled by changing the pH values, with high recovery of over 96%. And partitioning of the crude transglutaminase in this new ATPS was investigated for the first time. The main parameters, such as crude TGase feedstock load, the pH of system (pH 6.50-7.80), polymers concentration, and the types and concentration of salts, were studied to optimize partition conditions. In the 3% PADB4.91/2% PADB4.06 ATPS, enzyme recovery of 96.51%, partition coefficient of 4.23 and purification factor of 3.73 for TGase were obtained in the presence of 60 mmol/L MgSO4 and at pH 7.00. The result of sodium dodecyl sulfate-polyacrylamide gel electrophoresis shows that TGase can be well separated from crude extract.

Levels of terpenoids, mangiferin and phenolic acids in the pulp and peel of ripe mango fruit influenced by pre-harvest spray application of FeSO4 (Fe2+), MgSO4 (Mg2+) and MnSO4 (Mn2+).

Fe2+, Mg2+ and Mn2+ are enzyme cofactors in terpenoids biosynthesis. Effects of pre-harvest spray of FeSO4, MgSO4 and MnSO4 (0.2% and 0.3%) 30 d prior to harvest on the levels of terpenoids and phenolic compounds in ripe mango fruit were investigated. All treatments significantly increased lupeol in the peel compared to control and it was highest in pulp of 0.3% FeSO4-treated fruit. Spray of each nutrient (0.3%) increased total carotenoids in the pulp. Mangiferin in pulp was significantly higher in the fruit treated with 0.2% FeSO4, MgSO4 and MnSO4 compared to control and 0.3%. Concentrations of gallic, ferulic and caffeic acids in the peel and chlorogenic acid in pulp and peel were highest in fruit sprayed with 0.2% FeSO4. In conclusion, pre-harvest spray of FeSO4, MgSO4 and MnSO4 regulates concentrations of terpenoids and phenolic compounds in the pulp and peel of ripe mango fruit.

Humic acid attenuation of silver nanoparticle toxicity by ion complexation and the formation of a Ag3+ coating.

The use of silver nanoparticles (AgNPs) result in an inevitable contact with aquatic environments. Here we study the behavior of AgNPs and the developmental toxicity in zebrafish embryos exposed to these nanoparticles (0-10 mg/L) with and without the presence of HA (20 mg/L), using zebrafish facility water (ZFW) and zebrafish growing media (ZGM). The presence of cations and HA gave rise to a decrease in Ag ion release and ζ-potential, an increase in the hydrodynamic diameter and oxidation of the AgNP surface. The results show that the presence of HA and cations in the media, as well as the silver speciation, i.e., the unusual presence of Ag3+, decreases the toxicity of AgNPs (LC50AgNPs: 1.19 mg/L; LC50AgNPs + HA: 3.56 mg/L), as well as silver bioavailability and toxicity in zebrafish embryos. Developmental alterations and the LC50 (1.19 mg/L) of AgNPs in ZFW were more relevant (p ≤ 0.05) than for AgNPs in ZGM (LC50 ˃ 10 mg/L). It was demonstrated that the bioaccumulation and toxicity of AgNPs depends on several factors including AgNPs concentration, nanoparticle aggregation, dissolved silver ions, speciation of silver ions, the amount of salt in the environment, the presence of humic substances and others, and different combinations of all of these factors.

QuEChERS and ultra-high performance liquid chromatography-tandem mass spectrometry method for the determination of parabens and ultraviolet filters in human milk samples.

Concerns are growing about human exposure to endocrine disrupting chemicals (EDCs), especially during developmental stages. Parabens (PBs) and ultraviolet filters (UVFs) are prevalent EDCs widely used as additives in cosmetics and personal care products (PCPs). The objective of this study was to develop a method to determine four PBs and ten UVFs in human milk using QuEChERS treatment and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Multivariate strategies were applied to optimize experimental parameters. Limits of quantification ranged from 0.1 to 0.2 ng mL-1 and inter-day variability (evaluated as relative standard deviation) from 6% to 13%. The method was validated using matrix-matched standard calibration followed by a recovery assay with spiked samples. Recovery percentages ranged from 87% to 112%. The method was satisfactorily applied to assess target compounds in human milk samples from 15 donors. This analytical procedure can provide information on newborn exposure to these EDCs.

Determination of bisphenols with estrogenic activity in plastic packaged baby food samples using solid-liquid extraction and clean-up with dispersive sorbents followed by gas chromatography tandem mass spectrometry analysis.

Bisphenols (BPs) are a family of chemicals with known endocrine disrupting activity. Bisphenol A (BPA) is the most representative prototype of this group of chemicals. Recently, the use of BPA, a prototype of endocrine disruptors, has been reduced and replaced with structural analogs due to its negative effects on both the environment and consumers. In this work, a new method is presented for the determination of seven BPs, with estrogenic activity in ready-to-eat plastic packaged baby foods. The procedure involves the isolation of the analytes using solid-liquid phase extraction with acetonitrile followed by a clean-up step with a mixture of dispersive-SPE sorbents (C18 and PSA) and magnesium sulphate, to reduce matrix effect from proteins, sugars and lipids. Extraction parameters were optimized using multivariate optimization methods. The compounds were detected and quantified by gas chromatography tandem mass spectrometry (GC-MS/MS). The limits of quantification were between 0.1 and 1.2ngg-1 for the studied analytes. The method was validated using matrix-matched calibration and recovery assays with spiked samples. Recovery rates were between 91% and 110% and % RSD was lower than 13% in all cases. The method has been successfully applied for the determination of these endocrine disrupting chemicals (EDCs) in samples of a novel type of food consumed by pre-schoolers. This is the first study to analyze EDCs in plastic packaged foods consumed by this target group.