Search Results (13)

Introduction: Serum metabolome changes after acute ischemic stroke (AIS), but the significance of this is poorly understood. We evaluated whether this change is associated with AIS outcomes in patients with large vessel occlusion (LVO). To improve validity, we combined cross-sectional and longitudinal designs and analyzed serum using Nuclear Magnetic Resonance (NMR) and Liquid Chromatography–Mass Spectrometry (LC-MS). Methodology: In the cross-sectional part, we compared serum metabolome from 48 LVO strokes, collected at 48–72 h, and analyzed with NMR, while in the longitudinal part, we compared metabolome from 15 LVO strokes, collected at <24 h, 48–72 h, 5–7 days, and 80–120 days, and analyzed with LC-MS between patients with modified Rankin Scores (mRS) of 0–3 and 4–6 at 90 days. We hypothesized that compounds elevated in patients with mRS 0–3 in the cross-sectional part would also be elevated in the longitudinal part, and vice versa. We used regression for the analysis and TSBH for multiple testing. Results: In the cross-sectional part, cholesterol, choline, phosphoglycerides, sphingomyelins, and phosphatidylethanolamines had lower levels in patients with an mRS of 0–3 compared to an mRS of 4–6. In the longitudinal part, lower levels of sphingomyelin (d18:1/19:0, d19:1/18:0)* significantly correlated with an mRS of 0–3 in patients with small infarction volume, while lower levels of sphingolipid N-palmitoyl-sphingosine (d18:1/16:0), 1-palmitoyl-2-docosahexaenoyl-GPC (16:0/22:6), 1-palmitoyl-2-docosahexaenoyl-GPE, palmitoyl-docosahexaenoyl-glycerol (16:0/22:6), campesterol, and 3beta-hydroxy-5-cholestenoate correlated with an mRS of 0–3 in patients with large infarction volume. Conclusions: This pilot study showed that lower levels of lipidomic components nerve cell membrane correlate with good AIS outcomes. If proven on large-scale studies, these compounds may become important AIS outcome markers. Full article

Introduction: Globally, the health and quality of life of millions of people are negatively affected by diabetic foot ulcers (DFUs). To treat these chronic wounds, a novel injectable drug for closing DFUs composed of micronized amniotic membrane was developed. This new therapeutic drug for wound repair expands on traditional allograft therapies by allowing extracellular matrix proteins, growth factors, and cytokines to reach wound anatomies in DFUs that are difficult to treat. The aim of this study was to evaluate the components of the injectable drug. Methods: Liquid chromatography with tandem mass spectrometry and a Quantibody^® human cytokine array were conducted to identify and characterize growth factors and proteins known to contribute to wound healing. In addition, hyaluronic acid was quantified and compared between the injectable and human amniotic fluid using a hyaluronan enzyme-linked immunosorbent assay. Cell proliferation, migration, angiogenesis, and viability were evaluated to assess the performance of the novel injectable in vitro. The rheometric properties of the product were evaluated by assessing it pre- and post-injection through a 22-gauge needle to measure the viscosity using a shear- and temperature-dependent viscosity protocol. Results: Liquid chromatography with tandem mass spectrometry and Quantibody^® human cytokine array revealed growth factors and proteins imperative for wound healing. The quantified hyaluronic acid was compared between the injectable and human amniotic fluid, resulting in a statistically significant difference, with higher protein concentrations found in the injectable. In vitro qualitative and quantitative analysis confirmed an increase in cell viability, proliferation, and migration when treated with the drug. An evaluation of the rheometric properties of the injectable drug after passing through a 22-gauge cannula presented no alterations to the biologic drug. Conclusions: Collectively, these data present the potential of a novel injectable drug for the treatment of DFUs. Full article

This study describes the development of hydrogel formulations with ionic crosslinking capacity and photocatalytic characteristics. The objective of this research is to provide an effective, accessible, “green”, and facile route for the decontamination of chemical warfare agents (CWAs, namely the blistering agent—mustard gas/sulfur mustard (HD)) from contaminated surfaces, by decomposition and entrapment of CWAs and their degradation products inside the hydrogel films generated “on-site”. The decontamination of the notorious warfare agent HD was successfully achieved through a dual hydrolytic–photocatalytic degradation process. Subsequently, the post-decontamination residues were encapsulated within a hydrogel membrane film produced via an ionic crosslinking mechanism. Polyvinyl alcohol (PVA) and sodium alginate (ALG) are the primary constituents of the decontaminating formulations. These polymeric components were chosen for this application due to their cost-effectiveness, versatility, and their ability to form hydrogen bonds, facilitating hydrogel formation. In the presence of divalent metallic ions, ALG undergoes ionic crosslinking, resulting in rapid gelation. This facilitated prompt PVA-ALG film curing and allowed for immediate decontamination of targeted surfaces. Additionally, bentonite nanoclay, titanium nanoparticles, and a tetrasulfonated nickel phthalocyanine (NiPc) derivative were incorporated into the formulations to enhance absorption capacity, improve mechanical properties, and confer photocatalytic activity to the hydrogels obtained via Zn²⁺—mediated ionic crosslinking. The resulting hydrogels underwent characterization using a variety of analytical techniques, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), viscometry, and mechanical analysis (shear, tensile, and compression tests), as well as swelling investigations, to establish the optimal formulations for CWA decontamination applications. The introduction of the fillers led to an increase in the maximum strain up to 0.14 MPa (maximum tensile resistance) and 0.39 MPa (maximum compressive stress). The UV-Vis characterization of the hydrogels allowed the determination of the band-gap value and absorption domain. A gas chromatography–mass spectrometry assay was employed to evaluate the decontamination efficacy for a chemical warfare agent (sulfur mustard—HD) and confirmed that the ionic crosslinked hydrogel films achieved decontamination efficiencies of up to 92.3%. Furthermore, the presence of the photocatalytic species can facilitate the degradation of up to 90% of the HD removed from the surface and entrapped inside the hydrogel matrix, which renders the post-decontamination residue significantly less dangerous. Full article

For either healthy or diseased organisms, lipids are key components for cellular membranes; they play important roles in numerous cellular processes including cell growth, proliferation, differentiation, energy storage and signaling. Exercise and disease development are examples of cellular environment alterations which produce changes in these networks. There are indications that alterations in lipid metabolism contribute to the development and progression of a variety of cancers. Measuring such alterations and understanding the pathways involved is critical to fully understand cellular metabolism. The demands for this information have led to the emergence of lipidomics, which enables the large-scale study of lipids using mass spectrometry (MS) techniques. Mass spectrometry has been widely used in lipidomics and allows us to analyze detailed lipid profiles of cancers. In this article, we discuss emerging strategies for lipidomics by mass spectrometry; targeted, as opposed to global, lipid analysis provides an exciting new alternative method. Additionally, we provide an introduction to lipidomics, lipid categories and their major biological functions, along with lipidomics studies by mass spectrometry in cancer samples. Further, we summarize the importance of lipid metabolism in oncology and tumor microenvironment, some of the challenges for lipodomics, and the potential for targeted approaches for screening pharmaceutical candidates to improve the therapeutic efficacy of treatment in cancer patients. Full article

Large volumes of oil sands process-affected waters (OSPW) result from heavy oil extraction in Alberta, Canada. Currently, a toxic legacy of ca. 500 Mm³ is stored in tailings ponds under a zero-discharge policy. OSPW is a complex mixture of suspended and dissolved materials including a wide range of inorganic and organic contaminants. Classically defined naphthenic acids (NAs; C_nH_2n+ZO₂) are one of the primary toxic fractions in OSPW and have therefore been the subject of considerable research interest. Most studies employ considerable sample cleanup followed by liquid chromatography and/or high-resolution mass spectrometry (HRMS) for the characterization of these complex mixtures. However, these strategies can be time- and cost-intensive, limiting the scope of research and adoption for regulatory purposes. Condensed phase membrane introduction mass spectrometry (CP-MIMS) is emerging as a “fit-for-purpose” approach for the analysis of NAs. This technique directly interfaces the mass spectrometer with an aqueous sample using a hydrophobic semi-permeable membrane, requiring only pH adjustment to convert NAs to a membrane-permeable form. Here, we examine the perm-selectivity of classical NAs (O₂) relative to their more oxidized counterparts (O₃–O₇) and heteroatomic (N, S) species collectively termed naphthenic acid fraction compounds (NAFCs). The investigation of 14 model compounds revealed that classically defined NAs are greater than 50-fold more membrane permeable than their oxidized/heteroatomic analogs. HRMS analysis of real OSPW extracts with and without membrane clean-up further supported selectivity towards the toxic O₂ class of NAs, with >85% of the overall signal intensity attributable to O₂ NAs in the membrane permeate despite as little as 34.7 ± 0.6% O₂ NAs observed in the directly infused mixture. The information collected with HRMS is leveraged to refine our method for analysis of NAs at unit mass resolution. This new method is applied to 28 archived real-world samples containing NAs/NAFCs from constructed wetlands, OSPW, and environmental monitoring campaigns. Concentrations ranged from 0–25 mg/L O₂ NAs and the results measured by CP-MIMS (unit mass) and SPE-HRMS (Orbitrap) showed good agreement (slope = 0.80; R² = 0.76). Full article

Membrane introduction mass spectrometry (MIMS) is a direct mass spectrometry technique used to monitor online chemical systems or quickly quantify trace levels of different groups of compounds in complex matrices without extensive sample preparation steps and chromatographic separation. MIMS utilizes a thin, semi-permeable, and selective membrane that directly connects the sample and the mass spectrometer. The analytes in the sample are pre-concentrated by the membrane depending on their physicochemical properties and directly transferred, using different acceptor phases (gas, liquid or vacuum) to the mass spectrometer. Condensed phase (CP) MIMS use a liquid as a medium, extending the range to new applications to less-volatile compounds that are challenging or unsuitable to gas-phase MIMS. It directly allows the rapid quantification of selected compounds in complex matrices, the online monitoring of chemical reactions (in real-time), as well as in situ measurements. CP-MIMS has expanded beyond the measurement of several organic compounds because of the use of different types of liquid acceptor phases, geometries, dimensions, and mass spectrometers. This review surveys advancements of CP-MIMS and its applications to several molecules and matrices over the past 15 years. Full article

Hydrogen/Deuterium eXchange Mass Spectrometry (HDX-MS) is a rapidly evolving technique for analyzing structural features and dynamic properties of proteins. It may stand alone or serve as a complementary method to cryo-electron-microscopy (EM) or other structural biology approaches. HDX-MS is capable of providing information on individual proteins as well as large protein complexes. Owing to recent methodological advancements and improving availability of instrumentation, HDX-MS is becoming a routine technique for some applications. When dealing with samples of low to medium complexity and sizes of less than 150 kDa, conformation and ligand interaction analyses by HDX-MS are already almost routine applications. This is also well supported by the rapid evolution of the computational (software) background that facilitates the analysis of the obtained experimental data. HDX-MS can cope at times with analytes that are difficult to tackle by any other approach. Large complexes like viral capsids as well as disordered proteins can also be analyzed by this method. HDX-MS has recently become an established tool in the drug discovery process and biopharmaceutical development, as it is now also capable of dissecting post-translational modifications and membrane proteins. This mini review provides the reader with an introduction to the technique and a brief overview of the most common applications. Furthermore, the most challenging likely applications, the analyses of glycosylated and membrane proteins, are also highlighted. Full article

The scope of this article is to develop composite membranes using chitosan (CS) and graphene oxide (GO) as adsorbents for the removal of inorganic pollutants such as heavy metal ions, particularly Pb²⁺, from aqueous solutions. GO was obtained by modified Hummers method and blended with CS solution. The introduction of ethylenediaminetetraacetic acid (EDTA) compound to CS/GO suspension lead to an increased adsorption capacity of CS/GO for the elimination of heavy metals by forming stable chelates with them. The synthesized membranes were examined by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), and the adsorption behaviour of Pb²⁺ from aqueous solutions using CS/EDTA/GO membranes was evaluated using inductively coupled plasma mass spectrometry (ICP-MS). The adsorption performance of Pb²⁺ ions was studied by monitoring the concentration of Pb²⁺ against the adsorption period at an initial content of the adsorbent. The maximum adsorption efficiency of Pb²⁺ metal ions reached 767 mg·g⁻¹ for CS/EDTA/GO 0.1%, 889 mg·g⁻¹ for CS/EDTA/GO 0.3%, 970 mg·g⁻¹ for CS/EDTA, 853 mg·g⁻¹ for CS and 1526 mg·g⁻¹ for GO. These findings show promising potential for CS/EDTA/GO membranes as effective adsorbent materials for the removal of heavy metal ions in water. Full article

Membrane-introduction mass spectrometry (MIMS) has been presented as one of the promising approaches for online and real-time analysis of monochloramine (NH₂Cl) in diverse matrices such as air, human breath, and aqueous matrices. Selective pervaporation of NH₂Cl through the introduction membrane overcomes the need for sample preparation steps. However, both the selectivity and sensitivity of MIMS can be affected by isobaric interferences, as reported by several researchers. High-resolution mass spectrometry helps to overcome those interferences. Recent miniaturization of Fourier transform—ion cyclotron resonance—mass spectrometry (FT-ICR MS) technology coupled to the membrane-introduction system provides a potent tool for in field analysis of monochloramine in environmental matrices. Monochloramine analysis by MIMS based FT-ICR MS system demonstrated decomposition into ammonia. To further clarify the origin of this decomposition, headspace analyses after bypassing the membrane were undertaken and showed that monochloramine decomposition was not exclusively related to interactions within the membrane. Adsorption inside the MIMS device, followed by surface-catalyzed decomposition, was suggested as a plausible additional mechanism of monochloramine decomposition to ammonia. Full article

Baicalein, a famously effective component of the traditional Chinese medicine Rhizoma Huang Qin (Scutellaria altissima L.), has been proved to have potent neuroprotection and anti-platelet aggregation effects with few side effects. Meanwhile, recent studies have revealed that the introduction of amino acid to baicalein could improve its neuroprotective activity. In the present study, a series of novel baicalein amino acid derivatives were designed, synthesized, and screened for their neuroprotective effect against tert-butyl, hydroperoxide-induced, SH-SY5Y neurotoxicity cells and toxicity on the normal H9C2 cell line by standard methylthiazol tetrazolium (MTT) assay. In addition, all of the newly synthesized compounds were characterized by ¹H-NMR, ¹³C-NMR, and high resolution mass spectrometry (HR-MS). The results showed that most of the compounds provided more potent neuroprotection than baicalein, and were equivalent to the positive drug edaravin. They showed no obvious cytotoxicity on normal H9C2 cells. Notably, the most active compound 8 displayed the highest protective effect (50% effective concentration (EC₅₀) = 4.31 μM) against tert-butyl, hydroperoxide-induced, SH-SY5Y neurotoxicity cells, which was much better than the baicalein (EC₅₀ = 24.77 μM) and edaravin (EC₅₀ = 5.62 μM). Further research on the chick chorioallantoic membrane (CAM) model indicated that compound 8 could significantly increase angiogenesis, which might promote neurovascular proliferation. The detection of apoptosis analysis showed that compound 8 could dramatically alleviate morphological manifestations of cell damage. Moreover, the benzyloxycarbonyl (cbz)-protected baicalein amino acid derivatives showed better neuroprotective activity than the t-Butyloxy carbonyl (boc)-protected derivatives. Full article

Membrane inlet mass spectrometry (MIMS) is commonly used for detecting the components in liquid samples. When a liquid sample flows through a membrane, certain analytes will permeate into the vacuum chamber of a mass spectrometer from the solution. The properties of the membrane directly determine the substances that can be detected by MIMS. A capillary introduction (CI) method we previously proposed can also be used to analyze gas and volatile organic compounds (VOCs) dissolved in liquids. When CI analysis is carried out, the sample is drawn into the mass spectrometer with no species discrimination. The performance of these two injection methods was compared in this study, and similar response time and limit of detection (LOD) can be acquired. Specifically, MIMS can provide better detection sensitivity for most inorganic gases and volatile organic compounds. In contrast, capillary introduction shows wider compatibility on analyte types and quantitative range, and it requires less sample consumption. As the two injection methods have comparable characteristics and can be coupled with a miniature mass spectrometer, factors such as cost, pollution, device size, and sample consumption should be comprehensively considered when choosing a satisfactory injection method in practical applications. Full article

Introduction: Perfluoro-octanesulfonate (PFOS) and perfluoro-octanoic acid (PFOA) are two toxic perfluorochemicals (PFCs) commonly used as surfactants. PFCs are difficult to be eliminated from the body. We investigated the influence of different dialysis membranes on the concentrations of PFCs in patients under hemodialysis. Method: We enrolled 98 patients. Of these, 58 patients used hydrophobic polysulfone (PS) dialysis membranes, and the other 40 had hydrophilic membranes made by poly-methyl methacrylate (PMMA) or cellulose triacetate (CTA). Liquid chromatography tandem mass spectrometry coupled was used with isotope dilution to quantify PFOA and PFOS. Results: The predialysis concentrations of PFOA and PFOS in patients with hydrophobic PS dialysis membranes were 0.50 and 15.77 ng/mL, respectively, lower than the concentrations of 0.81 and 22.70 ng/mL, respectively, in those who used hydrophilic membranes (such as CTA or PMMA). Older patients have higher PFOS and poorer body function, with lower Karnofsky Performance Status Scale (KPSS) scores. The demographic data of the two groups were similar. However, patients with hydrophobic PS dialysis membranes had lower predialysis aspartate transaminase (AST) (p = 0.036), lower glucose levels (p = 0.017), and better body function (nonsignificantly higher KPSS scores, p = 0.091) compared with patients who used other membranes. These differences may be associated with the effects of different membranes, because PFOA positively correlated with AST, while PFOS negatively correlated with body function. Conclusions: This is the first study comparing PFC levels in uremic patients with different dialysis membrane. PS membrane may provide better clearance of PFCs and may, therefore, be beneficial for patients. Full article

Manipulations of cell surface glycosylation or glycan decoration of selected proteins hold immense potential for exploring structure-activity relations or increasing glycoprotein quality. Metabolic glycoengineering describes the strategy where exogenously supplied sugar analogues intercept biosynthetic pathways and are incorporated into glycoconjugates. Low membrane permeability, which so far limited the large-scale adaption of this technology, can be addressed by the introduction of acylated monosaccharides. In this work, we investigated tetra-O-acetylated, -propanoylated and -polyethylene glycol (PEG)ylated fucoses. Concentrations of up to 500 µM had no substantial effects on viability and recombinant glycoprotein production of human embryonic kidney (HEK)-293T cells. Analogues applied to an engineered Chinese hamster ovary (CHO) cell line with blocked fucose de novo synthesis revealed an increase in cell surface and recombinant antibody fucosylation as proved by lectin blotting, mass spectrometry and monosaccharide analysis. Significant fucose incorporation was achieved for tetra-O-acetylated and -propanoylated fucoses already at 20 µM. Sequential fucosylation of the recombinant glycoprotein, achieved by the application of increasing concentrations of PEGylated fucose up to 70 µM, correlated with a reduced antibody’s binding activity in a Fcγ receptor IIIa (FcγRIIIa) binding assay. Our results provide further insights to modulate fucosylation by exploiting the salvage pathway via metabolic glycoengineering. Full article