Picoplatin binding to proteins: X-ray structures and mass spectrometry data on the adducts with lysozyme and ribonuclease A.

The reactivity of the anticancer drug picoplatin (cis-amminedichlorido(2-methylpyridine)platinum(II) complex) with the model proteins hen egg white lysozyme (HEWL) and bovine pancreatic ribonuclease (RNase A) was investigated by electrospray ionisation mass spectrometry (ESI MS) and X-ray crystallography. The data were compared with those previously obtained for the adducts of these proteins with cisplatin, carboplatin and oxaliplatin under the same experimental conditions. ESI-MS data show binding of Pt to both proteins, with fragments retaining the 2-methylpyridine ligand and, possibly, a chloride ion. X-ray crystallography identifies different binding sites on the two proteins, highlighting a different behaviour of picoplatin in the absence or presence of dimethyl sulfoxide (DMSO). Metal-containing fragments bind to HEWL close to the side chains of His15, Asp18, Asp119 and both Lys1 and Glu7, whereas they bind to RNase A on the side chain of His12, Met29, His48, Asp53, Met79, His105 and His119. The data suggest that the presence of DMSO favours the loss of 2-methylpyridine and alters the ability of the Pt compound to bind to the two proteins. With both proteins, picoplatin appears to behave similarly to cisplatin and carboplatin when dissolved in DMSO, whereas it behaves more like oxaliplatin in the absence of the coordinating solvent. This study provides important insights into the pharmacological profile of picoplatin and supports the conclusion that coordinating solvents should not be used to evaluate the biological activities of Pt-based drugs.

Feasibility, safety, and efficacy of endovascular treatment of anterior cranial fossa dural arteriovenous fistulas: a systematic review and meta-analysis with a subanalysis for Onyx.

Dural Arteriovenous Fistulas (dAVFs) of the anterior cranial fossa (ACF) are uncommon but carry a high risk of hemorrhage and pose substantial treatment challenges. Recent advancements in endovascular treatment (EVT), including the introduction of novel liquid embolic agents, have markedly bolstered EVT's role in managing ACF-dAVFs, with notable series published in the last five years. We aimed to assess the feasibility, safety, and efficacy of EVT for ACF-dAVFs. We searched Medline, Scopus, Web of Science, and Cochrane Library databases following PRISMA guidelines. Eligible studies included those with ≥ 5 patients undergoing embolization of ACF-dAVFs, detailing both angiographic and clinical outcomes. We used single proportion analysis with 95% confidence intervals under a random-effects model, I2 to assess heterogeneity, and Baujat and sensitivity analysis to address high heterogeneity. Publication bias was assessed by funnel-plot analysis and Egger's test. Outcomes included complete occlusion following embolization, unsuccessful endovascular embolization attempts, incomplete occlusion following embolization, symptom resolution or clinical improvement following embolization, recurrence; procedure-related complications, morbidity, and mortality. Additionally, a subanalysis for studies exclusively utilizing Onyx™ embolic system was done. Eighteen studies comprising 231 ACF-dAVF were included. Unsuccessful endovascular embolization attempts rate was 2%. Complete occlusion rate was 85%, with 4% of complications. Incomplete occlusion rate was 10%. Successfully embolized patients experienced either symptom resolution or clinical improvement in 94% of cases. Morbidity and mortality rates were 1% and 0%, respectively. Onyx subanalyses showed an overall rate of 0% for unsuccessful attempts, 95% for complete occlusion, and 5% for incomplete occlusion. Symptom resolution or clinical improvement was 98% and recurrence rate was 0%. EVT for ACF-dAVF is highly feasible, effective, and safe, with a low rate of complications, morbidity, and mortality. The subanalyses focusing on Onyx embolizations revealed superior efficacy and safety outcomes compared to the findings of the primary analyses involving all included studies.

Formulation and evaluation of miconazole lipogel for enhanced drug permeation.

Hydrophilic drugs could be incorporated into the skin surface by manes of Lipogel. This study aimed to prepare miconazole lipogel with natural ingredients to enhance drug permeability using dimethyl Sulfoxide (DMSO). The miconazole lipogels, A1 (without DMSO) and A2 (with DMSO) were formulated and evaluated for organoleptic evaluation, pH, viscosity, stability studies, freeze-thawing, drug release profile and drug permeation enhancement. Results had stated that prepared lipogel's pH falls within the acceptable range required for topical delivery (4 to 6) while both formulations show good results in organoleptic evaluation. The A2 formulation containing DMSO shows better permeation of miconazole (84.76%) on the artificial skin membrane as compared to A1 lipogel formulation (50.64%). In in-vitro drug release studies, A2 for-mulation showed 87.48% drug release while A1 showed just 60.1% drug release from lipogel. Stability studies were performed on model formulations under environmental conditions and both showed good spreadibility, stable pH, free of grittiness and good consistency in formulation. The results concluded that A2 formulation containing DMSO shows better results as compared to DMSO-free drug lipogel.

Effective cryopreservation of human brain tissue and neural organoids.

Human brain tissue models and organoids are vital for studying and modeling human neurological disease. However, the high cost of long-term cultured organoids inhibits their wide-ranging application. It is therefore urgent to develop methods for the cryopreservation of brain tissue and organoids. Here, we establish a method using methylcellulose, ethylene glycol, DMSO, and Y27632 (termed MEDY) for the cryopreservation of cortical organoids without disrupting the neural cytoarchitecture or functional activity. MEDY can be applied to multiple brain-region-specific organoids, including the dorsal/ventral forebrain, spinal cord, optic vesicle brain, and epilepsy patient-derived brain organoids. Additionally, MEDY enables the cryopreservation of human brain tissue samples, and pathological features are retained after thawing. Transcriptomic analysis shows that MEDY can protect synaptic function and inhibit the endoplasmic reticulum-mediated apoptosis pathway. MEDY will enable the large-scale and reliable storage of diverse neural organoids and living brain tissue and will facilitate wide-ranging research, medical applications, and drug screening.

Morphological and Neurological Impairments Induced by Chronic Administration of Dimethyl Sulfoxide in Mice.

We studied the influence of DMSO administered ad libitum with drinking water in concentrations of 0.01, 0.1, and 1% for 4 and 6 weeks on pain sensitivity, motor coordination, and myelin content in the corpus callosum of C57BL/6 mice. After 6-week administration, DMSO in all studied concentrations decreased myelin content in the corpus callosum. Moreover, 4-week administration of 0.1% DMSO and 6-week administration of 1% DMSO increased the latency to fall in the rotarod test by 3.1 (p<0.05) and 5.1 (p<0.001) times, respectively. After 4-week administration of DMSO in concentrations of 0.01 and 0.1%, the latency of the tail flick response increased by 2.1 (p<0.05) and 1.8 times (p<0.001), respectively. Administration of DMSO in concentrations of 0.01 and 1% for 6 weeks led to a decrease of this parameter by 2.7 (p<0.05) and 3.8 times (p<0.01), respectively. Thus, DMSO in all studied concentrations decreased myelin content in the corpus callosum of C57BL/6 mice and modified motor coordination and pain sensitivity of animals.

DMSO synergized with sugars: optical clearing agent modulation of optical coherence tomography of skin tissues.

The stratum corneum of the outermost skin is an important barrier impeding transdermal permeation, and permeation enhancers can reduce the barrier resistance of the stratum corneum and enhance the permeation of drugs in tissues. The optical imaging depth, signal intensity, and scattering coefficient variation rules of skin tissues in time dimension are obtained by using optical coherence tomography (OCT). The effect of optical clearing agents (OCAs) on OCT imaging is obtained by quantitatively analyzing the changes in the optical properties of tissues. D-fructose, one of the monosaccharides, and sucrose, one of the disaccharides, were selected for the ex vivo optical clearing experiments on pig skin tissues utilizing the dimethyl sulfoxide (DMSO) carrier effect. We find that DMSO synergized with sugars applied to skin tissue has a more significant increase in the optical imaging depth and signal intensity, and a reduction in the scattering coefficient with an increasing concentration of DMSO. DMSO with a high concentration and D-fructose with saturated concentration (10:1; v/v) effectively reduce light attenuation in OCT imaging and improve the image quality. This operation will also shorten the application time to minimize skin damage from hyperosmotic agents.

Liver glycogen fragility in the presence of hydrogen-bond breakers.

Glycogen, a complex branched glucose polymer, is responsible for sugar storage in blood glucose homeostasis. It comprises small ß particles bound together into composite α particles. In diabetic livers, α particles are fragile, breaking apart into smaller particles in dimethyl sulfoxide, DMSO; they are however stable in glycogen from healthy animals. We postulate that the bond between ß particles in α particles involves hydrogen bonding. Liver-glycogen fragility in normal and db/db mice (an animal model for diabetes) is compared using various hydrogen-bond breakers (DMSO, guanidine and urea) at different temperatures. The results showed different degrees of α-particle disruption. Disrupted glycogen showed changes in the mid-infra-red spectrum that are related to hydrogen bonds. While glycogen α-particles are only fragile under harsh, non-physiological conditions, these results nevertheless imply that the bonding between ß particles in α particles is different in diabetic livers compared to healthy, and is probably associated with hydrogen bonding.

[Deciphering cellular processes responding to lethality of 17ß-estradiol by quantitative phosphoproteomics].

17ß-Estradiol (E2), an important endocrine hormone in the mammalian body, participates in the regulation of the physiological functions of the reproductive system, mammary glands, bone, and cardiovascular system, among others. Paradoxically, despite the physiological actions of endogenous E2 (0.2-1.0 nmol/L), numerous clinical and experimental studies have demonstrated that high-dose E2 treatment can cause tumor regression and exert pro-apoptotic actions in multiple cell types; however, the underlying mechanism remains undescribed. In particular, little information of the cellular processes responding to the lethality of E2 is available. In the present study, we attempted to characterize the cellular processes responding to high-dose (µmol/L) E2 treatment using quantitative phosphoproteomics to obtain a better understanding of the regulatory mechanism of E2-induced cell death. First, the cell phenotype induced by high-dose E2 was determined by performing Cell Counting Kit-8 assay (CCK8), cell cytotoxicity analysis by trypan blue staining, and microscopic imaging on HeLa cells treated with 1-10 µmol/L E2 or dimethyl sulfoxide (DMSO) for 1-3 d. E2 inhibited cell proliferation and induced cell death in a dose- and time-dependent manner. Compared with the DMSO-treated HeLa cells, the cells treated with 5 µmol/L E2 for 2 d demonstrated >74% growth inhibition and approximately 50% cell death. Thus, these cells were used for quantitative phosphoproteomic analysis. Next, a solid-phase extraction (SPE)-based immobilized titanium ion affinity chromatography (Ti4+-IMAC) phosphopeptide-enrichment method coupled with data-independent acquisition (DIA)-based quantitative proteomics was employed for the in-depth screening of high-dose E2-regulated phosphorylation sites to investigate the intracellular processes responding to high-dose E2 treatment. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) identified over 10000 phosphorylation sites regulated by E2 and DMSO in HeLa cells. In comparison with the DMSO-treated cells, the cells treated with 5 µmol/L E2 showed 537 upregulated phosphorylation sites and 387 downregulated phosphorylation sites, with a threshold of p<0.01 and |log2(fold change)|≥1. A total of 924 phosphorylation sites on 599 proteins were significantly regulated by high-dose E2, and these sites were subjected to enrichment analysis. In addition, 453 differently regulated phosphorylation sites on 325 proteins were identified only in the E2- or DMSO-treated cell samples. These phosphorylation sites may be phosphorylated or dephosphorylated in response to high-dose E2 stimulation and were subjected to parallel enrichment analyses. Taken together, 1218 phosphorylation sites on 741 proteins were significantly regulated by high-dose E2 treatment. The functional phosphoproteins in these two groups were then analyzed using Gene Ontology (GO) and Gene Set Enrichment Analysis (GSEA) to determine the biological processes in which they participate and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database. Consistent with the cell-phenotype data, cell cycle-related proteins were highly enriched in the two groups of E2-regulated phosphoproteins (p<0.05), indicating that high-dose E2 treatment can regulate cell proliferation. In addition, E2-regulated phosphoproteins were highly enriched in the cellular processes of ribosome biogenesis, nucleocytoplasmic transport, and messenger ribonucleic acid (mRNA) processing/splicing (p<0.05), indicating that the activation of these processes may contribute to high-dose E2-induced cell death. These results further confirm that high-dose E2 treatment inhibits protein translation and induces cell death. Furthermore, the significant upregulation of multiple phosphorylation sites associated with epidermal growth factor receptor (EGFR) and mitogen-activated protein kinases (MAPKs) MAPK1, MAPK4, and MAPK14 by high-dose E2 indicates that the EGFR and MAPK signaling pathways are likely involved in the regulation of E2-induced cell death. These phosphorylation sites likely play vital roles in E2-induced cell death in HeLa cells. Overall, our phosphoproteomic data could be a valuable resource for uncovering the regulatory mechanisms of E2 in the micromolar range.

Testing of arctic insect hemolymph as a secondary agent in applied cryopreservation.

BACKGROUND: Cold hardiness of insects from extremely cold regions is based on a principle of natural cryoprotection, which is associated with physiological mechanisms provided by cryoprotectants. OBJECTIVE: Since arctic cold-hardy insects are producers of highly effective cryoprotectants, in this study, the hemolymph of Aporia crataegi L. and Upis ceramboides L. from an extremely cold area (Yakutia) was tested as a secondary component of cryoprotective agents (CPA) for cryopreservation (-80 degree C) of human peripheral blood lymphocytes and skin fibroblasts. MATERIALS AND METHODS: Lymphocytes and skin fibroblasts were treated with various combinations of DMSO and hemolymph extract and step-wise cooled to -80 degree C. Post-cryopreservation cell viability was assessed by vital staining and morphological appearance. RESULTS: Viability was higher when cells were frozen with a mixture containing DMSO and Upis ceramboides hemolymph compared to the cells frozen in DMSO, while cells frozen with DMSO and Aporia crataegi hemolymph did not survive. The fact that hemolymph of not every cold-resistant insect can be used as a secondary agent along with DMSO indicates that only a unique combination of hemolymph components and its compatibility with cells might result in a positive effect. CONCLUSION: Although the use of insect hemolymph as a complementary agent in applied cryopreservation is a problem in terms of practical application, such studies could initiate new trends in the search for the most successful hemolymph-like cryoprotectant systems. https://doi.org/10.54680/fr24210110712.

A pyrene-based chromo-fluorogenic probe for specific detection of sarin gas mimic, diethylchlorophosphate.

Nerve agents are becoming serious issues for the healthy and sustainable environment of modern civilization. Therefore, its detection and degradation are of paramount importance to the scientific community. In the present contribution, we have introduced a chromo-fluorogenic pyrene-based  probe, (E)-2-methoxy-3-(pyren-1-ylimino)-3,8a-dihydro-2H-chromen-4-ol (PMCO) to detect sarin stimulant diethylchlorophosphate (DCP) in solution and gaseous phases. On inserting DCP in PMCO solution, a visual colorimetric change from yellow to clear colourless in daylight and highly intensified blue fluorescence was observed instantly under a 365 nm portable UV lamp light. PMCO has outstanding selectivity and high sensitivity with a limit of detection of 1.32 µM in dimethyl sulfoxide (DMSO) medium and 77.5 nM in 20% H2O-DMSO. A handy strained paper strip-based experiment was demonstrated to recognize DCP in a mixture of similar toxic analytes. A dip-stick experiment was performed to identify DCP vapour, and may be used as an effective photonic tool. We also demonstrated real sample analysis utilizing different DCP-spiked water samples and validating DCP detection even in various types of soils such as sand, field, and mud. Therefore, this present study provides an effective chemosensor for instant and on-site detection of toxic nerve agents in dangerous circumstances.

Cell Damage Mechanisms during Cryopreservation in a Zwitterion Solution and Its Alleviation by DMSO.

Recently, zwitterions have been proposed as novel cryoprotectants. However, some cells are difficult to cryopreserve using aqueous zwitterion solutions alone. We investigated here the reason for cell damage in such cells, and it was the osmotic pressure after freeze concentration. Furthermore, the addition of dimethyl sulfoxide (DMSO) has been reported to improve the cryoprotective effect in such cells: the zwitterion/DMSO aqueous solution shows a higher cryoprotective effect than the commercial cryoprotectant. This study also clarified the mechanisms underlying the improvement in a cryoprotective effect. The addition of cell-permeable DMSO alleviated the osmotic pressure after the freeze concentration. This alleviation was also found to be a key factor for cryopreserving cell spheroids, while there has been no insight into this phenomenon.

Acute Toxicity Assays with the Artemia salina Model: Assessment of Variables.

The use of the brine shrimp Artemia salina (Leach) in acute toxicity assays has great potential due to its simplicity, low cost and reproducibility. In the current study, some of the variables that can influence the reliability of the assay in terms of test organism survival, were evaluated as part of its implementation in our laboratory. The quality and type of water used, the buffer components and other parameters (salinity, pH and dissolved oxygen level), were all evaluated for optimisation purposes. DMSO (dimethyl sulphoxide) was used as the test substance in the toxicity assay, to evaluate the concentration limits as a solvent in sample preparation. Regarding the buffer salinity, pH and dissolved oxygen level, we found that a 25% to 30% deviation from the standard values did not affect the survival of the nauplii (the first-instar larval stage) under assay conditions. In summary, we corroborate the potential use of this model for the prediction of the toxic potential of substances, to inform future testing strategies.

Two-Step Effective Onyx Embolization from the Occipital Artery for the Treatment of Intracranial Dural Arteriovenous Fistula: A Technical Note.

AIM: To report our experience and the technique of two-step effective Onyx embolization from occipital artery (OA) for the obliteration of dural arteriovenous fistulas (DAVFs) with OA feeders. MATERIAL AND METHODS: The medical records of patients with intracranial DAVFs treated with trans-arterial embolization (TAE) using Onyx from the OA were retrospectively reviewed. RESULTS: Seven patients were included. The methods of Onyx injection from the OA were categorized as simple Onyx injection into the shunt, and two-step embolization. Two-step embolization involved the Onyx or coil embolization of the OA distal to the branching site of the feeders in the first step, and Onyx was injected toward the target shunt in the second step. Simple Onyx injection was performed in two cases; in both cases, the residual shunt remained. By contrast, the two-step embolization technique was performed in five cases, and in all those cases, sufficient embolization of the DAVFs was achieved. CONCLUSION: Prior embolization using Onyx or coil of the distal OA helped prevent Onyx from unexpected embolization through the subcutaneous branches that were not associated with the shunt, thereby leading to effective embolization. This new two-step embolization technique from the OA may improve the obliteration rate of DAVFs with OA feeders using TAE with Onyx.

Acidic solvent improves cisplatin action in in-vitro.

As cisplatin is one of the most broadly used chemotherapeutics, it is widely tested in vitro & in vivo assays, involving attempts to better understand its mechanism of action, develop strategies to mitigate its toxicity, or develop new drug combinations. Presently, for in vitro assays, dissolving cisplatin in dimethyl sulfoxide (DMSO) is discouraged due to its significant reduction in drug activity, Alternatively, inorganic solvents like normal saline (NS) are recommended. However, this approach is still problematic, including 1) instability of cisplatin in NS, 2) limited solubility, 3) the need to avoid long-term storage at -80 °C (or -20 °C) after dissolving, and 4) complications when combining with other DMSO-solubilized compounds. Here, we report a DMSO-HCl mixture as an alternative solvent to address these challenges. Cisplatin in DMSO-HCl not only retains comparable drug activity to cisplatin in NS but also exhibits increased stability over an extended period. Our brief report sheds light on cisplatin action, providing insights to aid in cancer research in vitro.

The crucial role of stability of intercalating agent for DNA binding studies in DMSO/water system.

In recent years, extensive research has been directed towards understanding the interactions between various zinc complexes with DNA, specifically delving into their intercalation and binding behaviors. The binding of zinc complexes to DNA is particularly intriguing due to their distinctive intercalating capabilities. This study unveils a remarkable phenomenon observed with a specific Zn complex, ([B-Zn-N3], where B is a Schiff base ligand), during DNA intercalation investigations in the popular DMSO-Water binary solvent mixture. An unanticipated observation revealed time-dependent changes in the UV-visible absorption spectroscopic studies, coupled with the existence of an isosbestic point. This observation questions the stability of the intercalating agent itself during the intercalation process. The emergence of a decomposed product during the intercalation study has been confirmed through various analytical techniques, including CHN analysis, MALDI mass, XPS, Raman spectroscopy, and Powder XRD. The change in the chemical species on intercalation is further substantiated by theoretical studies, adding depth to our understanding of the intricate dynamics at play during DNA intercalation with the [B-Zn-N3] complex in the DMSO-Water system.

Dimethyl sulfoxide as a gas phase charge-reducing agent for the determination of PEGylated proteins' intact mass.

Determination of PEGylated proteins' intact mass by mass spectrometry is challenging due to the molecules' large size, excessive charges, and instrument limitations. Previous efforts have been reported. However, signal variability, ion coalescence, and a generally low degree of robustness have been observed. In this work, we have explored the capabilities of post-column infusion of dimethyl sulfoxide (DMSO) following reversed-phase liquid chromatography-mass spectrometry (RP-LCMS) to determine PEG-filgrastim' intact mass, and to characterize its PEG moiety. The method was optimized around reproducibility (six preparations, and three injection replicates) with an in-house prepared PEG-filgrastim standard. The method showed a mass accuracy of ≤1.2 Da. The average molecular weight (MWEO=483) was 40 147.9 Da. The number average molecular weight (Mn) and the weight average molecular weight (Mw) were observed to be 40 101.1 and 40 113.9 Da, respectively, both with an RSD of 0.03%. The molecular weight distribution of ethylene oxide (EO), the polydispersity index (PDI), was 1.0003 for all preparations with a minimum and maximum number of EO units of 448 ± 2 and 516 ± 2, respectively. The method was finally applied to commercially available Neulasta® lots where the Mn and Mw were 39 995.8 and 40 008.8 Da, respectively, both with an RSD of 0.1%. The minimum and maximum EO units across the lots were observed to be 444.5 ± 1.5 and 514 ± 3, respectively. The PDI for all Neulasta® lots was 1.0003. This study provides an insightful characterization of Neulasta® and describes a robust LC-MS methodology for the characterization of the PEGylated proteins.

DMSO and Its Role in Differentiation Impact Efficacy of Human Adenovirus (HAdV) Infection in HepaRG Cells.

Differentiated HepaRG cells are popular in vitro cell models for hepatotoxicity studies. Their differentiation is usually supported by the addition of dimethyl sulfoxide (DMSO), an amphipathic solvent widely used in biomedicine, for example, in potential novel therapeutic drugs and cryopreservation of oocytes. Recent studies have demonstrated drastic effects, especially on epigenetics and extracellular matrix composition, induced by DMSO, making its postulated inert character doubtful. In this work, the influence of DMSO and DMSO-mediated modulation of differentiation on human adenovirus (HAdV) infection of HepaRG cells was investigated. We observed an increase in infectivity of HepaRG cells by HAdVs in the presence of 1% DMSO. However, this effect was dependent on the type of medium used for cell cultivation, as cells in William's E medium showed significantly stronger effects compared with those cultivated in DMEM. Using different DMSO concentrations, we proved that the impact of DMSO on infectability was dose-dependent. Infection of cells with a replication-deficient HAdV type demonstrated that the mode of action of DMSO was based on viral entry rather than on viral replication. Taken together, these results highlight the strong influence of the used cell-culture medium on the performed experiments as well as the impact of DMSO on infectivity of HepaRG cells by HAdVs. As this solvent is widely used in cell culture, those effects must be considered, especially in screening of new antiviral compounds.

Modulation of bacterial membranes and cellular macromolecules by dimethyl sulfoxide: A dose-dependent study providing novel insights.

Using Escherichia coli as a model, this manuscript delves into the intricate interactions between dimethyl sulfoxide (DMSO) and membranes, cellular macromolecules, and the effects on various aspects of bacterial physiology. Given DMSO's wide-ranging use as a solvent in microbiology, we investigate the impacts of both non-growth inhibitory (1.0 % and 2.5 % v/v) and slightly growth-inhibitory (5.0 % v/v) concentrations of DMSO. The results demonstrate that DMSO causes alterations in bacterial membrane potential, influences the electrochemical characteristics of the cell surface, and exerts substantial effects on the composition and structure of cellular biomolecules. Genome-wide gene expression data from DMSO-treated E. coli was used to further investigate and bolster the results. The findings of this study provide valuable insights into the complex relationship between DMSO and biological systems, with potential implications in drug delivery and cellular manipulation. However, it is essential to exercise caution when utilizing DMSO to enhance the solubility and delivery of bioactive compounds, as even at low concentrations, DMSO exerts non-inert effects on cellular macromolecules and processes.

Recurrent thunderclap headache after endovascular embolization of pial AV malformation by onyx material.

Thunderclap headache is a sudden severe headache with onset to peak within one minute. Multiple excruciating, short-lived thunderclap headaches over a few days to weeks are highly suggestive of reversible cerebral vasoconstriction syndrome (RCVS). RCVS can be primary or secondary to several factors, but it is rarely described after neuro-endovascular procedures using onyx material. A 10-year-old child presented with RCVS heralded by recurrent thunderclap headache following endovascular embolization of pial arteriovenous malformation with onyx material (contains organic solvent dimethyl sulfoxide). Dimethyl sulfoxide is an angiotoxic material that can cause dysregulation of cerebral vascular tone triggering reversible cerebral vasoconstriction syndrome. Recurrent thunderclap headache after embolization procedures using onyx material should prompt for the diagnosis of reversible cerebral vasoconstriction syndrome.

Systematic cryopreservation study of cardiac myoblasts in suspension.

H9c2 myoblasts are a cell line derived from embryonic rat heart tissue and demonstrate the ability to differentiate to cardiac myotubes upon reduction of the serum concentration (from 10% to 1%) and addition of all-trans retinoic acid in the growth medium. H9c2 cells are increasingly being used as an easy-to-culture proxy for some functions of cardiomyocytes. The cryobiology of cardiac cells including H9c2 myoblasts has not been studied as extensively as that of some cell types. Consequently, it is important to characterize the cryobiological response and systematically develop well-optimized cryopreservation protocols for H9c2 cells to have optimal and consistent viability and functionality after thaw for high quality studies with this cell type. In this work, an interrupted slow cooling protocol (graded freezing) was applied to characterize H9c2 response throughout the cooling profile. Important factors that affect the cell response were examined, and final protocols that provided the highest post-thaw viability are reported. One protocol uses the common cryoprotectant dimethyl sulfoxide combined with hydroxyethyl starch, which will be suitable for applications in which the presence of dimethyl sulfoxide is not an issue; and the other protocol uses glycerol as a substitute when there is a desire to avoid dimethyl sulfoxide. Both protocols achieved comparable post-thaw viabilities (higher than 80%) based on SYTO 13/GelRed flow cytometry results. H9c2 cells cryopreserved by either protocol showed ability to differentiate to cardiac myotubes comparable to fresh (unfrozen) H9c2 cells, and their differentiation to cardiac myotubes was confirmed with i) change in cell morphology, ii) expression of cardiac marker troponin I, and iii) increase in mitochondrial mass.