Dimethyl Sulfoxide Concentration Research Articles

HMSCs in contact with DMSO for cryopreservation: Experiments and modeling of osmotic injury and cytotoxic effect.

In this study a combined analysis of osmotic injury and cytotoxic effect useful for the optimization of the cryopreservation process of a cell suspension is carried out. The case of human Mesenchymal Stem Cells (hMSCs) from Umbilical Cord Blood (UCB) in contact with dimethyl sulfoxide (DMSO) acting as Cryo‐Protectant Agent (CPA) is investigated from the experimental as well as the theoretical perspective. The experimental runs are conducted by suspending the cells in hypertonic solutions of DMSO at varying osmolality, system temperature, and contact times; then, at room temperature, cells are pelleted by centrifugation and suspended back to isotonic conditions. Eventually, cell count and viability are measured by means of a Coulter counter and flow‐cytometer, respectively. Overall, a decrease in cell count and viability results when DMSO concentration, temperature, and contact time increase. A novel mathematical model is developed and proposed to interpret measured data by dividing the cell population between viable and nonviable cells. The decrease of cell count is ascribed exclusively to the osmotic injury caused by expansion lysis: excessive swelling causes the burst of both viable as well as nonviable cells. On the other hand, the reduction of cell viability is ascribed only to cytotoxicity which gradually transforms viable cells into nonviable ones. A chemical reaction engineering approach is adopted to describe the dynamics of both phenomena: by following the kinetics of two chemical reactions during cell osmosis inside a closed system it is shown that the simultaneous reduction of cell count and viability may be successfully interpreted. The use of the Surface Area Regulation (SAR) model recently proposed by the authors allows one to avoid the setting in advance of fixed cell Osmotic Tolerance Limits (OTLs), as traditionally done in cryopreservation literature to circumvent the mathematical simulation of osmotic injury. Comparisons between experimental data and theoretical simulations are provided: first, a nonlinear regression analysis is performed to evaluate unknown model parameters through a best‐fitting procedure carried out in a sequential fashion; then, the proposed model is validated by full predictions of system behavior measured at operating conditions different from those used during the best‐fit procedure.

Delamination by Repulsive Osmotic Swelling of Synthetic Na-Hectorite with Variable Charge in Binary Dimethyl Sulfoxide-Water Mixtures.

Swelling of clays is hampered by increasing layer charge. With vermiculite-type layer charge densities, crystalline swelling is limited to the two-layer hydrate, while osmotic swelling requires ion exchange with bulky and hydrophilic organic molecules or with Li+ cations to trigger repulsive osmotic swelling. Here, we report on surprising and counterintuitive osmotic swelling behavior of a vermiculite-type synthetic clay [Na0.7]inter[Mg2.3Li0.7]oct[Si4]tetO10F2 in mixtures of water and dimethyl sulfoxide (DMSO). Although swelling in pure water is restricted to crystalline swelling, with the addition of DMSO, osmotic swelling sets in at some threshold composition. Finally, when the DMSO concentration is increased further to 75 vol %, swelling is restricted again to crystalline swelling as expected. Repulsive osmotic swelling thus is observed in a narrow composition range of the binary water-DMSO mixture, where a freezing point suppression is observed. This suppression is related to DMSO and water molecules exhibiting strong interactions leading to stable molecular clusters. Based on this phenomenological observation, we hypothesize that the unexpected swelling behavior might be related to the formation of different complexes of interlayer cations being formed at different compositions. Powder X-ray diffraction and 23Na magic angle spinning-NMR evidence is presented that supports this hypothesis. We propose that the synergistic solvation of the interlayer sodium at favorable compositions exerts a steric pressure by the complexes formed in the interlayer. Concomitantly, the basal spacing is increased to a level, where entropic contributions of interlayer species lead to a spontaneous thermodynamically allowed one-dimensional dissolution of the clay stack.

A novel antibacterial benzimidazolium hexachlorotellurate hybrid compound: Experimental-theoretical characterization

Inspired by the antibacterial properties of recent hybrid materials containing hexahalogenotellurate anions, a novel hybrid compound, formulated as (C7H7N2)2TeCl6.(H2O)2 (T3), was synthesized by slow evaporation from a mixture of tellurium dioxide and HCl added to a benzimidazole solution at room temperature. T3 was fully characterized using various methods such as X-ray diffraction (SC-XRD & XRPD), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–Vis), Mass spectroscopy (MS), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The single crystal X-ray analysis showed that T3 crystallizes in the monoclinicP21/m space group with good reliability factor and that its crystal structure is organized by an alternation of hexachlorotellurate octahedral polyhedra {TeCl6} and benzimidazolium planes {C7H7N2} joined together through hydrogen bonds that ensure the cohesion and the overall stability. Exhaustive vibrational and optical studies of T3 were performed through infrared absorption at room temperature and UV–vis spectroscopies, respectively. In the ultraviolet area T3 has three absorption signals corresponding to charge transfers in the organic part, between the organic and inorganic moieties, and in the inorganic complex, as computationally confirmed. Theoretical calculations also reveal a HOMO-LUMO gap of 3.95 eV, large enough as to indicate stability against intramolecular electron excitation. Thermogravimetric data of the thermal decomposition of T3 were also analysed revealing that the weight loss occurs in three stages. An isoconversional method was used for computing the activation energy and its variation along the thermal decomposition. Finally, and as a main feature of T3, antibacterial activity against Escherichia coli and Staphylococcus aureus stains has been tested and confirmed after incubation for 24 h at 37 °C of T3 diluted at different concentrations (0.5–2 mg/ml) in ethanol or dimethyl sulfoxide (DMSO).

Dimethyl Sulfoxide: A Bio-Friendly or Bio-Hazard Chemical? The Effect of DMSO in Human Fibroblast-like Synoviocytes.

The effect of dimethyl sulfoxide (DMSO) in rheumatoid arthritis (RA) human fibroblast-like synoviocytes (FLSs) has been studied on five different samples harvested from the joints (fingers, hands and pelvis) of five women with RA. At high concentrations (>5%), the presence of DMSO induces the cleavage of caspase-3 and PARP-1, two phenomena associated with the cell death mechanism. Even at a 0.5% concentration of DMSO, MTT assays show a strong toxicity after 24 h exposure (≈25% cell death). Therefore, to ensure a minimum impact of DMSO on RA FLSs, our study shows that the concentration of DMSO has to be below 0.05% to be considered safe.

Different Effects of Salt Bridges near the Active Site of Cold-Adapted Proteus mirabilis Lipase on Thermal and Organic Solvent Stabilities

Organic solvent-tolerant (OST) enzymes have been discovered in psychrophiles. Cold-adapted OST enzymes exhibit increased conformational flexibility in polar organic solvents resulting from their intrinsically flexible structures. Proteus mirabilis lipase (PML), a cold-adapted OST lipase, was used to assess the contribution of salt bridges near the active site involving two arginine residues (R237 and R241) on the helix η1 and an aspartate residue (D248) on the connecting loop to the thermal and organic solvent stabilities of PML. Alanine substitutions for the ion pairs (R237A, R241A, D248A, and R237A/D248A) increased the conformational flexibility of PML mutants compared to that of the wild-type PML in an aqueous buffer. The PML mutants became more susceptible to denaturation after increasing the dimethyl sulfoxide or methanol concentration than after a temperature increase. Methanol was more detrimental to the structural stability of PML compared to dimethyl sulfoxide. These results suggest that direct interactions of dimethyl sulfoxide and methanol with the residues near the active site can have a destructive effect on the structure of PML compared with the global effect of heat on the protein structure. This study provides insight into the conformational changes within an OST enzyme with different effects on its thermal and organic solvent stabilities.

P1380: DEGREE OF CELL PACKING OF CRYOPRESERVED AT -80ºC HEMATOPOIETIC STEM CELLS DOES NOT AFFECT THEIR VIABILITY AND HEMATOLOGIC RECOVERY OF TRANSPLANTED MYELOMA PATIENTS

Background: Dimethylsulfoxide (DMSO) is toxic to both cryopreserved cells and patients. We are using a method for freezing at - 80ºC with 5% final DMSO concentration. Aims: In an attempt to further decrease the amount of infused DMSO we tested viability of cells and hematologic recovery of patients following cryopreservation with different degree of cell packing. Methods: We compared two groups of myeloma patients with low and high cryopreserved cells concentration. Cell suspension in the first group of 88 patients contained average 175x106 cells/ml (maximum 250x106 cells/ml) and in the second group of 175 patients the cells were completely packed by total plasma removal (average 391x106 cells/ml and maximum 597 x106 cells/ml) before adding the cryoprotectants resulting in a 60% decrease of the volume to be frozen. Cells were non-programmed frozen and stored at -80ºC in a solution with final concentrations of 5% DMSO, 3.6% hydroxyethyl starch (HES 450 000 mw) and 3% of human serum albumin. Stem cell viability was evaluated by trypan blue exclusion test. Cell dose in the first patient group was 2,62x106/kg (0,8–6,6), while in the second group it was 2,67x106/kg (1,5-6,8). Results: There was no statistically significant difference between the two myeloma patient groups. Viability was 97,0% (85-99) and 96,5 % (70-99) respectively. The neutrophil recovery was on day 11 (9-19) for the first and on day 11 (9-18) for the second group. Platelets recovered after 12 days for the first and the second group. Summary/Conclusion: Dimethylsulfoxide is toxic and induces many side effects following transplant (cardiac, neurologic, respiratory, etc.), which are dose dependent. Reducing them could be achieved by lowering the final DMSO concentration (5%) and by decreasing the volume of the frozen suspension. Our approach does not affect the cellular viability or the hematologic recovery of the patients following transplantation.

Optimization of the conditions for the immobilization of glycopolypeptides on hydrophobic silica particulates and simple purification of lectin using glycopolypeptide-immobilized particulates

Glycopolypeptide-immobilized particulates exhibit high binding selectivities and affinities for several analytes. However, to date, the conditions for the synthesis of glycopolypeptide-immobilized particulates have not been optimized and the application of these particulates as carriers for affinity chromatography has not been reported. Accordingly, herein, as a model compound for determining the optimal conditions for the immobilization of an artificial glycopolymer on hexyl-containing hybrid silica particulates (HSPs), the glycopolypeptide poly [GlcNAcβ1,4GlcNAc-β-NHCO-(CH2)5NH-/CH3(CH2)9NH-/γ-PGA] (3) containing multivalent chitobiose moieties and multivalent decyl groups with a γ-polyglutamic acid backbone was synthesized. Immobilization of 3 on HSPs under each condition was evaluated by a lectin-binding assay using wheat germ (Triticum vulgaris) agglutinin (WGA), which is an N-acetylglucosamine-binding lectin. As a result, the optimal immobilization conditions for HSPs at 25 mg/mL were obtained at dimethyl sulfoxide (DMSO) concentration of reaction solvent in the range of 1(DMSO):9(water) to 4(DMSO):6(water) and a compound 3 concentration in the range of 125 nM–1250 nM. Furthermore, the influence of the alkyl group structure introduced into glycopolypeptide for imparting hydrophobicity to it on the immobilization of glycopolypeptide on HSPs was investigated. As a result of comparing three types, poly [GlcNAcβ1,4GlcNAc-β-NHCO-(CH2)5NH-/γ-PGA] (1) with no alkyl group, poly [GlcNAcβ1,4GlcNAc-β-NHCO-(CH2)5NH-/CH3(CH2)4NH-/γ-PGA] (2) with a pentyl group, and 3 with a decyl group, 3 showed the best immobilization efficiency on HSPs. Finally, 1 mg 3-immobilized HSPs prepared under the optimum conditions adsorbed approximately 7.5 μg WGA in a structure-specific manner. We also achieved a simple WGA purification from raw wheat germ extract as a practical example using 3-immobilized HSPs. We believe that in the future, these glycopolypeptide-immobilized particulates will be used not only for the purification of plant lectins, but also as specific adsorbents for various lectins-like substances such as in vivo lectins, pathogenic viruses, and toxin proteins.

The Microbiological Drivers of Temporally Dynamic Dimethylsulfoniopropionate Cycling Processes in Australian Coastal Shelf Waters.

The organic sulfur compounds dimethylsulfoniopropionate (DMSP) and dimethyl sulfoxide (DMSO) play major roles in the marine microbial food web and have substantial climatic importance as sources and sinks of dimethyl sulfide (DMS). Seasonal shifts in the abundance and diversity of the phytoplankton and bacteria that cycle DMSP are likely to impact marine DMS (O) (P) concentrations, but the dynamic nature of these microbial interactions is still poorly resolved. Here, we examined the relationships between microbial community dynamics with DMS (O) (P) concentrations during a 2-year oceanographic time series conducted on the east Australian coast. Heterogenous temporal patterns were apparent in chlorophyll a (chl a) and DMSP concentrations, but the relationship between these parameters varied over time, suggesting the phytoplankton and bacterial community composition were affecting the net DMSP concentrations through differential DMSP production and degradation. Significant increases in DMSP were regularly measured in spring blooms dominated by predicted high DMSP-producing lineages of phytoplankton (Heterocapsa, Prorocentrum, Alexandrium, and Micromonas), while spring blooms that were dominated by predicted low DMSP-producing phytoplankton (Thalassiosira) demonstrated negligible increases in DMSP concentrations. During elevated DMSP concentrations, a significant increase in the relative abundance of the key copiotrophic bacterial lineage Rhodobacterales was accompanied by a three-fold increase in the gene, encoding the first step of DMSP demethylation (dmdA). Significant temporal shifts in DMS concentrations were measured and were significantly correlated with both fractions (0.2–2 μm and >2 μm) of microbial DMSP lyase activity. Seasonal increases of the bacterial DMSP biosynthesis gene (dsyB) and the bacterial DMS oxidation gene (tmm) occurred during the spring-summer and coincided with peaks in DMSP and DMSO concentration, respectively. These findings, along with significant positive relationships between dsyB gene abundance and DMSP, and tmm gene abundance with DMSO, reinforce the significant role planktonic bacteria play in producing DMSP and DMSO in ocean surface waters. Our results highlight the highly dynamic nature and myriad of microbial interactions that govern sulfur cycling in coastal shelf waters and further underpin the importance of microbial ecology in mediating important marine biogeochemical processes.

Dimethyl sulfoxide as a novel thermodynamic inhibitor of carbon dioxide hydrate formation

• Dimethyl sulfoxide decreases the thermodynamic stability of carbon dioxide hydrate. • Obtained CO 2 hydrate dissociation data are reliable and thermodynamically coherent. • Phases of sI hydrate, crystalline ice I h , and solid CO 2 were identified by PXRD. • DMSO avoids inclusion into the CO 2 hydrate framework. • DMSO is an effective thermodynamic inhibitor of CO 2 hydrate formation. The paper investigates dimethyl sulfoxide (DMSO) as a promising inhibitor of gas hydrates. The equilibrium conditions of the CO 2 hydrate were measured over a broad range of temperatures (from 243 K to 283 K) and DMSO concentrations (up to 50 mass%). DMSO decreases the thermodynamic stability of the CO 2 hydrate. Thermodynamic coherence of new hydrate equilibria data was demonstrated. The sI hydrate, crystalline ice I h , and solid CO 2 phases were identified using PXRD at 143 K. Measured unit cell parameter for sI hydrate (11.86 Å) coincided with the pure sI CO 2 hydrate literature value. The DMSO inhibition activity grows much faster in water solution in comparison to lower alcohols. We explain this behavior by the more pronounced non-ideality of DMSO water solutions. Thus, DMSO can be considered an effective thermodynamic inhibitor of the formation of CO 2 hydrate, superior in anti-hydrate activity to alcohol THIs within a specific range.

Monitoring Protein Global and Local Parameters in Unfolding and Binding Studies: The Extended Applicability of the Diffusion Coefficient─Molecular Size Empirical Relations.

Protein unfolding and denaturation are main issues in biochemical and pharmaceutical research. Using a global parameter, the translational diffusion coefficient D, folded, unfolded, and intrinsically disordered proteins of a given molar mass M can be distinguished based on their distinct hydrodynamic properties. For broader applications, we provide generalized, PFG-NMR-based empirical D-M relations validated at different temperatures and ready to use with the corresponding corrections in different media. We demonstrate that these relations enable a more accurate molecular mass determination and show fewer potential errors than those of the common methods based on small-molecular diffusion standards. We monitor unfolding of three model proteins using 8 M urea and dimethyl sulfoxide (DMSO)-water mixtures as denaturing agents, highlighting the effect of disulfide bonds. Denaturation in 8 M urea is pH-dependent; in addition, for proteins with highly stable disulfide bonds, a reducing agent (TCEP) is required to achieve complete unfolding. Regarding the effect of local parameters, we show that at low DMSO concentrations─common conditions in pharmaceutical binding studies─the PFG-NMR-derived global parameters are not significantly affected. Still, the atomic environments can change, and the bound solvent molecule can inhibit the binding of a partner molecule. Using proteins with natural isotopic abundance, this effect can be proven by fast 1H-15N 2D correlation spectra. Our results enable fast and easy estimation of protein molecular mass and the degree of folding in various media; moreover, the effect of the cosolvent on the atomic-level structure can be traced without the need of isotope labeling.

Ecotoxic effects of the vehicle solvent dimethyl sulfoxide on Raphidocelis subcapitata, Daphnia magna and Brachionus calyciflorus

ABSTRACT Dimethyl sulfoxide (DMSO) is widely used as a vehicle solvent in ecotoxicity bioassays.Despite its frequent use, it could be toxic for organisms at some concentrations. Hence, this study aims to investigate the effects of DMSO on the model organisms: microalgae Raphidocelis subcapitata, microcrustacean Daphnia magna, and rotifer Brachionus calyciflorus. DMSO was applied to the organisms in concentrations ranging from 0.031% to 4%. For R. subcapitata the lowest observed effect concentration (LOEC) after 72 h of exposure was 0.125% DMSO. The 50% effective concentration (EC50) was 2.138 ± 0.372%. In D. magna, significant differences in the mobility after 24 h or 48 h of exposure were observed for 1% DMSO being 1.712 ± 0.207% and 1.167 ± 0.220% DMSO the EC50 observed for 24 h and 48 h exposure, respectively. For B. calyciflorus, it was not possible to validate the tests performed, as there were insufficient animals alive in the control conditions at the end of the exposure period. Therefore, we recommended avoiding DMSO as a vehicle in assays using B. calyciflorus, and to use final DMSO concentrations in an experimental solution not exceeding 0.125% for R. subcapitata and 0.5% for D. magna. Finally, using a maximum of 0.01% DMSO is safe for the organisms tested. The effects of the vehicle solvent dimethyl sulfoxide (DMSO) were investigated in three aquatic model organisms, the microalgae Raphidocelis subcapitata, the microcrustacean Daphnia magna and the rotifer Brachionus calyciflorus. As a result, negative effects on growth rate for the algae population, immobilisation of daphnids and inhibition of rotifer reproduction was observed obtaining EC50 close to 1% of DMSO for all these cases.

Insights into the crystallization and vitrification of cryopreserved cells

Freezing of natural biomaterials results in the formation of ice crystals and the generation of hypertonicity, both of which are deleterious to biomaterials. Although the cryopreservation of cells, tissues, and even organs has been achieved empirically by vitrification using cryoprotectants, the underlying mechanisms are poorly understood. To better understand the crystallization and vitrification processes of cryoprotected cells, onion epidermal cells immersed in dimethyl sulfoxide (DMSO) solutions with different concentrations were employed as platforms. The crystallization and vitrification dynamic processes of the individual and multiple monolayer cells were recorded using a high-speed microscope camera and the forms of the intracellular and extracellular ices were further confirmed by corresponding Raman spectra. The effects of DMSO concentration and cooling/warming rate on both processes were investigated and the findings were of an important significance to improve the understanding of the mechanisms of intracellular ice formation in individual cells and the ice propagation between adjacent cells. It is expected to provide a theoretical basis for cryopreservation by vitrification and point toward a new pathway for developing cryopreservation protocols.

In vitro characteristics of cryopreserved platelet concentrates reconstituted by fresh frozen or lyophilized plasma.

Six percent dimethyl sulfoxide (DMSO) cryopreservation of platelet concentrates (PCs) allow longer storage of PCs but require time-consuming post-thaw washing. An alternative process based on removing supernatant before freezing has been implemented in several centres worldwide. We assessed the in vitro characteristics of cryopreserved PCs (CPPs) prepared according to this latest process using either French lyophilized plasma (FLyP) or fresh frozen plasma (FFP) for reconstitution. FLyP provides additional benefits to the process due to its logistical constraints and quick availability. Apheresis PCs (n=16) and buffy coat PCs (n=16) were cryopreserved in 6% DMSO. After storage at -80°C, PCs were thawed and reconstituted with FFP or FLyP. Volume, residual leukocytes, total platelet counts (TPCs), post-thaw recovery, biochemical parameters, and DMSO concentration were assessed. Platelet functions were analysed by swirling index, viscoelastometric assay and CD62P quantification. After reconstitution, TPC was above 2.1011/CPs; recovery was 78±14% with no significant difference between FFP and FLyP. Glucose and lactate levels were not different between plasmas, whereas FLyP-CPPs exhibited a significant increase in LDH and significantly lower pH. Residual DMSO was 8±4G/L. Functional analysis revealed significant differences between FFP and FLyP-CPPs, with lower clot firmness and increased clot initiation. Activation of platelets was not higher in FLyP-CPPs. Preparing CPPs according to this "new" process fulfilled the French legal criteria regardless of the type of plasma. Differences highlighted between FFP-CPPs and FLyP-CPPs were unlikely to be of clinical relevance.

Cryopreservation of HEP-G2 Cells Attached to Substrates: The Benefit of Sucrose and Trehalose in Combination with Dimethyl Sulfoxide

BACKGROUND: Cryopreservation of mammalian cells is mainly done in cryovials as free cell suspension in 5 to10% (v/v) dimethyl sulfoxide (DMSO). Relatively little attention has been paid to cryopreservation of adherent cell monolayers. OBJECTIVE: To investigate the appropriate cryoprotectant (CPA) formulations for the cryopreservation on HEP-G2 human tumor cells attached to the polystyrene plate and plastic surfaces. MATERIALS AND METHODS: Five CPA formulations were evaluated for the cryopreservation of HEP-G2 cells attached to polystyrene plates and and plastic coverslips, using post-thaw cell viability as a performance indicator. RESULTS AND CONCLUSION: Hep-G2 cells attached to the plastic coverslips and polystyrene plate surfaces were successfully cryopreserved in 10% DMSO with sucrose and trehalose. The addition of saccharides enabled the reduction of DMSO concentration, replaced serum, and improved the functional capacity of post-thaw Hep-G2 cells. Cells attached to the plastic coverslips show significantly better results than those attached to the polystyrene plate surfaces after cryopreservation.

Innovative Approach in the Cryogenic Freezing Medium for Mesenchymal Stem Cells.

The physical stresses during cryopreservation affect stem cell survival and further proliferation. To minimize or prevent cryoinjury, cryoprotective agents (CPAs) are indispensable. Despite the widespread use of 10% dimethyl sulfoxide (DMSO), there are concerns about its potential adverse effects. To bypass those effects, combinations of CPAs have been investigated. This study aimed to verify whether high-molecular-hyaluronic acid (HMW-HA) serves as a cryoprotectant when preserving human mesenchymal stem cells (hMSCs) to reduce the DMSO concentration in the cryopreservation medium. We studied how 0.1% or 0.2% HMW-HA combined with reduced DMSO concentrations (from 10% to 5%, and 3%) affected total cell count, viability, immunophenotype, and differentiation potential post-cryopreservation. Immediately after cell revival, the highest total cell count was observed in 10% DMSO-stored hMSC. However, two weeks after cell cultivation an increased cell count was seen in the HMW-HA-stored groups along with a continued increase in hMSCs stored using 3% DMSO and 0.1% HMW-HA. The increased total cell count corresponded to elevated expression of stemness marker CD49f. The HA-supplemented cryomedium did not affect the differential potential of hMSC. Our results will participate in producing a ready-to-use product for cryopreservation of mesenchymal stem cells.

Comparison of cryoprotectants in hematopoietic cell infusion-related adverse events.

The standard cryoprotectant for human cellular products is dimethyl sulfoxide (DMSO), which is associated with hematopoietic cell infusion-related adverse events (HCI-AEs) in hematopoietic stem cell transplantation including peripheral blood stem cell (PBSC) transplantation (PBSCT). DMSO is often used with hydroxyethyl starch (HES), which reduces DMSO concentration while maintaining the postthaw cell recovery. The cryoprotectant medium CP-1 (Kyokuto Pharmaceutical Industrial) is widely used in Japan. After mixture of a product with CP-1, DMSO and HES concentrations are 5% and 6%, respectively. However, the safety profile of CP-1 in association with HCI-AEs has not been investigated. To compare CP-1 with other cryoprotectants, we conducted a subgroup analysis of PBSCT recipients in a prospective surveillance study for HCI-AEs. Moreover, we validated the toxicity of CP-1 in 90 rats following various dose administration. The PBSC products cryopreserved with CP-1 (CP-1 group) and those with other cryoprotectants, mainly 10% DMSO (non-CP-1 group), were infused into 418 and 58 recipients, respectively. The rate of ≥grade 2 HCI-AEs was higher in the CP-1 group, but that of overall or ≥grade 3 HCI-AEs was not significantly different, compared to the non-CP-1 group. Similarly, after propensity score matching, ≥grade 2 HCI-AEs were more frequent in the CP-1 group, but the ≥grade 3 HCI-AE rate did not differ significantly between the groups. No significant toxicity was detected regardless of the CP-1 dose in the 90 rats. Infusion of a CP-1-containing PBSC product is feasible with the respect of HCI-AEs.

Effects of Phytoplankton on the Production and Emission of Estuarine Dimethyl Sulfide Under Different Nutrient Inputs From Changjiang River

AbstractContinuous input from the Changjiang River significantly reshuffled the ecosystems in the Changjiang Estuary and adjacent East China Sea, impacting the production, distribution, and emission of marine dimethyl sulfide (DMS). However, the effect of phytoplankton biomass and composition on DMS under different nutrient inputs remains poorly understood. Two comprehensive cruises to characterize their effects were conducted in spring and summer 2015. The areas with high concentrations of DMS, dimethylsulfoniopropionate (precursor of DMS), and dimethyl sulfoxide (photo‐oxidation product of DMS) were largely consistent with high phytoplankton abundances along the front of Changjiang Diluted Water in both seasons. Both the higher conversion ratio of dissolved dimethylsulfoniopropionate to DMS and the higher DMS biological production rate in summer contributed to the higher DMS levels. Once produced in seawater, more than half of the DMS was directly consumed by microbes, resulting in a turnover time of 1–2 days, which was shorter than that driven by ventilation. A ship‐based incubation experiment revealed that, with increasing N/Si and N/P ratios from the Changjiang River, phytoplankton biomass increased and the community shifted from diatom‐dominated to dinoflagellate‐dominated, which was conducive to DMS production. It was noteworthy that strong DMS photo‐degradation induced by high nitrate concentrations may have masked DMS production to some extent, while urea only had a promoting effect and therefore led to a maximum increase in DMS yield. Our findings indicated that the increase in phytoplankton biomass and succession of phytoplankton community induced by changes in nutrient inputs will promote DMS emissions from the Changjiang Estuary.

Redefining the Molecular Interplay between Dimethyl Sulfoxide, Lipid Bilayers, and Dehydration.

The potentially damaging action of dimethyl sulfoxide (DMSO) on phospholipid bilayers remains a matter of controversy. We have conducted a series of long-scale molecular dynamics simulations of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) bilayers at various levels of hydration in the presence of variable quantities of DMSO. These simulations provide evidence for a non-destructive dehydrating mechanism of action for DMSO on DOPC bilayers across a wide concentration range and levels of hydration. Specifically, under full- and low-hydration conditions, the bilayer underwent a minor lateral contraction, coinciding with surface dehydration in the presence of dilute DMSO solutions (XDMSO < 0.3). At higher DMSO concentrations, this bilayer structure was retained despite a progressive deterioration of the hydration structure at the interface. A similar convergence of bilayer structural properties was observed under dehydration conditions for 0.3 < XDMSO < 0.7. Destabilization occurred for dehydrated bilayers in the presence of XDMSO ≥ 0.7, suggesting the existence of a DMSO concentration and/or dehydration threshold. However, such DMSO concentrations far exceed those established as toxic to other cellular components. Our findings represent a computational model for DMSO-DOPC interactions that is consistent with a range of experimental characterizations, offering new molecular insights into the cryoprotective mechanisms of action of DMSO.

Low dose DMSO treatment induces oligomerization and accelerates aggregation of \u03b1-synuclein

Dimethyl sulfoxide (DMSO) is a highly utilized small molecule that serves many purposes in scientific research. DMSO offers unique polar, aprotic and amphiphilic features, which makes it an ideal solvent for a wide variety of both polar and nonpolar molecules. Furthermore, DMSO is often used as a cryoprotectant in cell-based research. However, recent reports suggest that DMSO, even at low concentration, might interfere with important cellular processes, and cause macromolecular changes to proteins where a shift from α-helical to β-sheet structure can be observed. To investigate how DMSO might influence current research, we assessed biochemical and cellular impacts of DMSO treatment on the structure of the aggregation-prone protein α-synuclein, which plays a central role in the etiology of Parkinson’s disease, and other brain-related disorders, collectively termed the synucleinopathies. Here, we found that addition of DMSO increased the particle-size of α-synuclein, and accelerated the formation of seeding-potent fibrils in a dose-dependent manner. These fibrils made in the presence of DMSO were indistinguishable from fibrils made in pure PBS, when assessed by proteolytic digestion, cytotoxic profile and their ability to seed cellular aggregation of α-synuclein. Moreover, as evident through binding to the MJFR-14-6-4-2 antibody, which preferentially recognizes aggregated forms of α-synuclein, and a bimolecular fluorescence complementation assay, cells exposed to DMSO experienced increased aggregation of α-synuclein. However, no observable α-synuclein abnormalities nor differences in neuronal survival were detected after oral DMSO-treatment in either C57BL/6- or α-synuclein transgenic F28 mice. In summary, we demonstrate that low concentrations of DMSO makes α-synuclein susceptible to undergo aggregation both in vitro and in cells. This may affect experimental outcomes when studying α-synuclein in the presence of DMSO, and should call for careful consideration when such experiments are planned.

Dimethyl sulfoxide (DMSO) is a stabilizing co-solvent for G-quadruplex DNA.

We report the effect of dimethyl sulfoxide (DMSO) on the stability of the four-stranded structures formed by the oligodeoxyribonucleotides d[5'-AGGG(TTAGGG)3-3'] (HTel), d[5'-(GGGT)3GGG-3'] (G3T), d[5'-GGTTGGTGTGGTTGG-3] (TBA), d[5'-GGGGTTTTGGGG-3'] (Oxy-1.5), and d[5'-TGGGGT-3'] (TG4T). In these measurements, influence of the co-solvent was assessed by the change in the mid-point of the heat-induced unfolding, Tm, by monitoring the change in the UV absorption of the sample. Increasing concentrations of DMSO led to an increase in the Tm from the folded to unfolded states. We have also studied the effect of the denaturant urea and mixtures of urea and DMSO on the stability of the intramolecular HTel and the intermolecular TG4T G-quadruplexes. Consistent with earlier data, we found that urea destabilized the folded G-quadruplex structure; the Tm decreases with increasing urea concentration. However, in solutions containing both urea and DMSO, we observed that the two co-solvents off-set the destabilizing and stabilizing effect, respectively, of one another. That is, in solutions containing urea, increasing concentrations of DMSO led to the increase of the Tm of the G-quadruplex structure. This effect is observed in solutions containing sodium, potassium, or ammonium as the ion that stabilizes the folded G-quadruplex structure. The complementary effect of the two co-solvents presumably arises from differential interactions between urea and DMSO and the oligonucleotide or the cations involved in the stabilization of the G-quadruplexes. These results highlight the importance of co-solutes and co-solvents in systems containing guanine-rich DNA, particularly experimental processes that require DMSO.