36 results on '"Ismail FS"'
Search Results
2. A review on 3-D magnetic property testing system for measuring rotational core loss of soft magnetic materials
- Author
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Asari, AR, Guo, Y, Zhu, J, Ismail, FS, Asari, AR, Guo, Y, Zhu, J, and Ismail, FS
- Abstract
© 2015 IEEE. In today's world, the development of electromagnetic devices require the magnetic cores to be operated at higher frequency. Soft magnetic composite (SMC) materials are suitable for these applications because of their properties like high electrical resistivity which leads to the low eddy current loss, and 3-D magnetic isotropy which provides great design flexibility of various electromagnetic devices. On top of that, the prediction of core losses is very important in obtaining the optimum design of the electrical machines which is always aiming for high efficiency. This paper reviews the development of 3-D magnetic property testing system or 3-D tester in studying the rotational core loss of SMC materials based on the previous researches in the last decade.
- Published
- 2015
3. Microglia as potential key regulators in viral-induced neuroinflammation.
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Ismail FS, Faustmann TJ, Faustmann PM, and Corvace F
- Abstract
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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- 2024
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4. Tiagabine and zonisamide differentially regulate the glial properties in an astrocyte-microglia co-culture model of inflammation.
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Ismail FS, Faustmann PM, Förster E, Corvace F, and Faustmann TJ
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- Rats, Animals, Coculture Techniques, Tiagabine metabolism, Tiagabine pharmacology, Connexin 43 metabolism, Zonisamide pharmacology, Zonisamide metabolism, Cell Communication, Neuroglia metabolism, Inflammation pathology, Astrocytes, Microglia
- Abstract
Due to the role of astrocytes and microglia in the pathophysiology of epilepsy and limited studies of antiseizure medication (ASM) effects on glial cells, we studied tiagabine (TGB) and zonisamide (ZNS) in an astrocyte-microglia co-culture model of inflammation. Different concentrations of ZNS (10, 20, 40, 100 µg/ml) or TGB (1, 10, 20, 50 µg/ml) were added to primary rat astrocytes co-cultures with 5-10% (M5, physiological conditions) or 30-40% (M30, pathological inflammatory conditions) microglia for 24 h, aiming to study glial viability, microglial activation, connexin 43 (Cx43) expression and gap-junctional coupling. ZNS led to the reduction of glial viability by only 100 µg/ml under physiological conditions. By contrast, TGB revealed toxic effects with a significant, concentration-dependent reduction of glial viability under physiological and pathological conditions. After the incubation of M30 co-cultures with 20 µg/ml TGB, the microglial activation was significantly decreased and resting microglia slightly increased, suggesting possible anti-inflammatory features of TGB under inflammatory conditions. Otherwise, ZNS caused no significant changes of microglial phenotypes. The gap-junctional coupling was significantly decreased after the incubation of M5 co-cultures with 20 and 50 µg/ml TGB, which can be related to its anti-epileptic activity under noninflammatory conditions. A significant decrease of Cx43 expression and cell-cell coupling was found after the incubation of M30 co-cultures with 10 µg/ml ZNS, suggesting additional anti-seizure effects of ZNS with the disruption of glial gap-junctional communication under inflammatory conditions. TGB and ZNS differentially regulated the glial properties. Developing novel ASMs targeting glial cells may have future potential as an "add-on" therapy to classical ASMs targeting neurons., (© 2023. The Author(s).)
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- 2023
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5. The potential role of astroglial GABA A receptors in autoimmune encephalitis associated with GABA A receptor antibodies and seizures.
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Ismail FS and Faustmann PM
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- Animals, Humans, Receptors, GABA-A metabolism, Astrocytes metabolism, Seizures, gamma-Aminobutyric Acid physiology, Carrier Proteins, Antibodies metabolism, Encephalitis, Autoimmune Diseases of the Nervous System
- Abstract
The γ-aminobutyric acid (GABA) is the main inhibitory transmitter in the central nervous system and GABA receptors mediate the inhibitory synaptic transmission. GABA binding to neuronal GABA
A R leads to a rapid hyperpolarization and a higher excitation threshold due to an increase in membrane Cl- permeability. The synaptic GABAA R is mostly composed of two α(1-3), two β, and one γ subunit with the most abundant configuration α1β2γ2. Recently, antibodies (Abs) against α1, β3, and γ2 subunits of GABAA R were detected in a severe form of autoimmune encephalitis with refractory seizures, status epilepticus, and multifocal brain lesions, affecting gray and white matter. Experimental studies confirmed multiple mechanisms and direct functional effects of GABAA R Abs on neurons with decreased GABAergic synaptic transmission and increased neuronal excitability. The expression of GABAA R on astrocytes is well established. However, extensive studies about the effects of autoimmune GABAA R Abs on astrocytic GABAA R are missing. We hypothesize that GABAA R Abs may lead additionally to blocking astrocytic GABAA Rs with impaired Ca2+ homeostasis/spreading, astrocytic Cl- imbalance, dysfunction of astrocyte-mediated gliotransmission (e.g., decreased adenosine levels) and accumulation of excitatory neurotransmission, all this contributing to seizures, variable clinical/MRI presentations, and severity. The most abundant expressed GABAA R subunits in rodent astrocytes are α1, α2, β1, β3, and γ1 localized in both white and gray matter. Data about GABAA R subunits in human astrocytes are even more limited, comprising α2, β1, and γ1. Overlapping binding of GABAA R Abs to neuronal and astroglial receptors is still possible. In vitro and in vivo animal models can be helpful to test the effects of GABAA R Abs on glia. This is from an epileptological point of view relevant because of the increasing evidence, confirming the glial involvement in the pathogenesis of epilepsy. Taken together, autoimmune disorders are complex and multiple mechanisms including glia could contribute to the pathogenesis of GABAA R encephalitis with seizures., (© 2023 The Authors. Epilepsia Open published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)- Published
- 2023
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6. Inhibition of Microglial Activation by Amitriptyline and Doxepin in Interferon-β Pre-Treated Astrocyte-Microglia Co-Culture Model of Inflammation.
- Author
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Faustmann TJ, Wawrzyniak M, Faustmann PM, Corvace F, and Ismail FS
- Abstract
Depression may occur in patients with multiple sclerosis, especially during interferon-β (IFN-β) treatment, and therapy with antidepressants may be necessary. Interactions of IFN-β with antidepressants concerning glia-mediated inflammation have not yet been studied. Primary rat co-cultures of astrocytes containing 5% (M5, consistent with "physiological" conditions) or 30% (M30, consistent with "pathological, inflammatory" conditions) of microglia were incubated with 10 ng/mL amitriptyline or doxepin for 2 h, or with 2000 U/mL IFN-β for 22 h. To investigate the effects of antidepressants on IFN-β treatment, amitriptyline or doxepin was added to IFN-β pre-treated co-cultures. An MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was performed to measure the glial cell viability, immunocytochemistry was performed to evaluate the microglial activation state, and ELISA was performed to measure pro-inflammatory TNF-α and IL-6 cytokine concentrations. Incubation of inflammatory astrocyte-microglia co-cultures with amitriptyline, doxepin or IFN-β alone, or co-incubation of IFN-β pre-treated co-cultures with both antidepressants, significantly reduced the extent of inflammation, with the inhibition of microglial activation. TNF-α and IL-6 levels were not affected. Accordingly, the two antidepressants did not interfere with the anti-inflammatory effect of IFN-β on astrocytes and microglia. Furthermore, no cytotoxic effects on glial cells were observed. This is the first in vitro study offering novel perspectives in IFN-β treatment and accompanying depression regarding glia.
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- 2023
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7. A genome-wide association study in autoimmune neurological syndromes with anti-GAD65 autoantibodies.
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Strippel C, Herrera-Rivero M, Wendorff M, Tietz AK, Degenhardt F, Witten A, Schroeter C, Nelke C, Golombeck KS, Madlener M, Rüber T, Ernst L, Racz A, Baumgartner T, Widman G, Doppler K, Thaler F, Siebenbrodt K, Dik A, Kerin C, Räuber S, Gallus M, Kovac S, Grauer OM, Grimm A, Prüss H, Wickel J, Geis C, Lewerenz J, Goebels N, Ringelstein M, Menge T, Tackenberg B, Kellinghaus C, Bien CG, Kraft A, Zettl U, Ismail FS, Ayzenberg I, Urbanek C, Sühs KW, Tauber SC, Mues S, Körtvélyessy P, Markewitz R, Paliantonis A, Elger CE, Surges R, Sommer C, Kümpfel T, Gross CC, Lerche H, Wellmer J, Quesada CM, Then Bergh F, Wandinger KP, Becker AJ, Kunz WS, Meyer Zu Hörste G, Malter MP, Rosenow F, Wiendl H, Kuhlenbäumer G, Leypoldt F, Lieb W, Franke A, Meuth SG, Stoll M, and Melzer N
- Subjects
- Humans, Proteome genetics, Histocompatibility Antigens Class II, HLA Antigens, Haplotypes, Alleles, Autoantibodies, HLA-DRB1 Chains genetics, Genome-Wide Association Study, Genetic Predisposition to Disease genetics
- Abstract
Autoimmune neurological syndromes (AINS) with autoantibodies against the 65 kDa isoform of the glutamic acid decarboxylase (GAD65) present with limbic encephalitis, including temporal lobe seizures or epilepsy, cerebellitis with ataxia, and stiff-person-syndrome or overlap forms. Anti-GAD65 autoantibodies are also detected in autoimmune diabetes mellitus, which has a strong genetic susceptibility conferred by human leukocyte antigen (HLA) and non-HLA genomic regions. We investigated the genetic predisposition in patients with anti-GAD65 AINS. We performed a genome-wide association study (GWAS) and an association analysis of the HLA region in a large German cohort of 1214 individuals. These included 167 patients with anti-GAD65 AINS, recruited by the German Network for Research on Autoimmune Encephalitis (GENERATE), and 1047 individuals without neurological or endocrine disease as population-based controls. Predictions of protein expression changes based on GWAS findings were further explored and validated in the CSF proteome of a virtually independent cohort of 10 patients with GAD65-AINS and 10 controls. Our GWAS identified 16 genome-wide significant (P < 5 × 10-8) loci for the susceptibility to anti-GAD65 AINS. The top variant, rs2535288 [P = 4.42 × 10-16, odds ratio (OR) = 0.26, 95% confidence interval (CI) = 0.187-0.358], localized to an intergenic segment in the middle of the HLA class I region. The great majority of variants in these loci (>90%) mapped to non-coding regions of the genome. Over 40% of the variants have known regulatory functions on the expression of 48 genes in disease relevant cells and tissues, mainly CD4+ T cells and the cerebral cortex. The annotation of epigenomic marks suggested specificity for neural and immune cells. A network analysis of the implicated protein-coding genes highlighted the role of protein kinase C beta (PRKCB) and identified an enrichment of numerous biological pathways participating in immunity and neural function. Analysis of the classical HLA alleles and haplotypes showed no genome-wide significant associations. The strongest associations were found for the DQA1*03:01-DQB1*03:02-DRB1*04:01HLA haplotype (P = 4.39 × 10-4, OR = 2.5, 95%CI = 1.499-4.157) and DRB1*04:01 allele (P = 8.3 × 10-5, OR = 2.4, 95%CI = 1.548-3.682) identified in our cohort. As predicted, the CSF proteome showed differential levels of five proteins (HLA-A/B, C4A, ATG4D and NEO1) of expression quantitative trait loci genes from our GWAS in the CSF proteome of anti-GAD65 AINS. These findings suggest a strong genetic predisposition with direct functional implications for immunity and neural function in anti-GAD65 AINS, mainly conferred by genomic regions outside the classical HLA alleles., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Guarantors of Brain.)
- Published
- 2023
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8. Experimental Investigations of Monomethyl and Dimethyl Fumarate in an Astrocyte-Microglia Co-Culture Model of Inflammation.
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Corvace F, Faustmann TJ, Heckers S, Faustmann PM, and Ismail FS
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- Rats, Animals, Astrocytes, Connexin 43 metabolism, Connexin 43 pharmacology, Coculture Techniques, Inflammation metabolism, Dimethyl Fumarate metabolism, Dimethyl Fumarate pharmacology, Microglia metabolism
- Abstract
Introduction: Multiple sclerosis (MS) is the most common chronic inflammatory, demyelinating disease of the central nervous system. Dimethyl fumarate (DMF) and monomethyl fumarate (MMF) belong to the disease-modifying drugs in treatment of MS. There is evidence that astrocytes and microglia are involved in MS pathology, but few studies are available about MMF and DMF effects on astrocytes and microglia. The aim of this study was to investigate the effects of MMF and DMF on microglial activation and morphology as well as potential effects on glial viability, Cx43, and AQP4 expressions in different set-ups of an in vitro astrocyte-microglia co-culture model of inflammation., Methods: Primary rat glial co-cultures of astrocytes containing 5% (M5, mimicking "physiological" conditions) or 30% (M30, mimicking "pathological, inflammatory" conditions) of microglia were treated with different concentrations of MMF (0.1, 0.5, and 2 μg/mL) or DMF (1.5, 5, and 15 μM) for 24 h. Viability, proliferation, and cytotoxicity of glial cells were examined using MTT assay. Immunocytochemistry was performed to analyze the microglial phenotypes. Connexin 43 (Cx43) and aquaporin 4 (AQP4) expressions were quantified by immunoblot analysis., Results: Treatment with different concentrations of MMF or DMF for 24 h did not change the glial cell viability in M5 and M30 co-cultures. Microglial phenotypes were not altered by DMF under physiological M5 conditions, but treatment with higher concentration of DMF (15 μM) induced microglial activation under inflammatory M30 conditions. Incubation with different concentrations of MMF had no effects on microglial phenotypes. The Cx43 expression in M5 and M30 co-cultures was not changed significantly by immunoblot analysis after incubation with different concentrations of DMF or MMF for 24 h. The AQP4 expression was significantly increased in M5 co-cultures after incubation with 5 μm DMF. Under the other conditions, AQP4 expression was not affected by DMF or MMF., Discussion: In different set-ups of the astrocyte-microglia co-culture model of inflammation, MMF has not shown significant effects. DMF had only limited effects on microglia phenotypes and AQP4 expression. In summary, mechanisms of action of fumarates probably do not involve direct effects on microglia phenotypes as well as Cx43 and AQP4 expression., (© 2023 S. Karger AG, Basel.)
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- 2023
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9. Brivaracetam exhibits mild pro-inflammatory features in an in vitro astrocyte-microglia co-culture model of inflammation.
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Ismail FS, Faustmann PM, Kümmel ML, Förster E, Faustmann TJ, and Corvace F
- Abstract
Implications of glia in the pathophysiology of epilepsy raise the question of how these cells besides neurons are responsive to antiseizure medications (ASMs). Understanding ASM effects on glia and glia-mediated inflammation may help to explore astrocytes and microglia as potential targets for alternative anti-epileptogenic therapies. The aim of this study was to investigate the effects of the new generation ASM brivaracetam (BRV) in an astrocyte-microglia co-culture model of inflammation. Primary rat astrocytes co-cultures containing 5%-10% (M5, "physiological" conditions) or 30%-40% (M30, "pathological inflammatory" conditions) of microglia were treated with different concentrations of BRV (0.5, 2, 10, and 20 μg/ml) for 24 h. Glial cell viability was measured by MTT assay. Microglial activation states were analyzed by immunocytochemistry and astroglial connexin 43 (Cx43) expression by Western blot analysis and immunocytochemistry. Gap-junctional coupling was studied via Scrape Loading. Incubation with high, overdose concentration (20 μg/ml) of BRV significantly reduced the glial cell viability under physiological conditions ( p < 0.01: **). Treatment with BRV in therapeutic concentrations (0.5 and 2 μg/ml) reduced the resting microglia ( p < 0.05: *) and increased the microglial activation under inflammatory conditions ( p < 0.01: **). Astroglial Cx43 expression was not affected. The gap-junctional coupling significantly increased only by 0.5 μg/ml BRV under physiological conditions ( p < 0.05: *). Our findings suggest mild pro-inflammatory, in vitro features of BRV with regard to microglia morphology. BRV showed no effects on Cx43 expression and only limited effects on gap-junctional coupling. Reduction of glial viability by overdose BRV indicates possible toxic effects., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ismail, Faustmann, Kümmel, Förster, Faustmann and Corvace.)
- Published
- 2022
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10. Diagnostic challenges in patients with temporal lobe seizures and features of autoimmune limbic encephalitis.
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Ismail FS, Spatola M, Woermann FG, Popkirov S, Jungilligens J, Bien CG, Wellmer J, and Schlegel U
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- Autoantibodies, Autoimmune Diseases, Humans, Magnetic Resonance Imaging methods, Memory Disorders complications, Seizures complications, Seizures etiology, Temporal Lobe diagnostic imaging, Epilepsy, Temporal Lobe complications, Epilepsy, Temporal Lobe diagnostic imaging, Limbic Encephalitis diagnosis, Limbic Encephalitis diagnostic imaging
- Abstract
Background and Purpose: Consensus criteria for autoimmune limbic encephalitis (ALE) allow for a diagnosis even without neuronal antibodies (Abs), but it remains unclear which clinical features should prompt neuronal Ab screening in temporal lobe epilepsy patients. The aim of the study was to investigate whether patients with temporal lobe seizures associated with additional symptoms or signs of limbic involvement may harbor neuronal Abs, and which clinical features should prompt neuronal Ab screening in these patients., Methods: We identified 47 patients from a tertiary epilepsy center with mediotemporal lobe seizures and additional features suggestive of limbic involvement, including either memory deficits, psychiatric symptoms, mediotemporal magnetic resonance imaging (MRI) hyperintensities or inflammatory cerebrospinal fluid (CSF). Neuronal Ab testing was carried out at two independent reference laboratories (Bielefeld-Bethel, Germany, and Barcelona, Spain). All brain MRI scans were assessed by two reviewers independently., Results: Temporal lobe seizures were accompanied by memory deficits in 35/46 (76%), psychiatric symptoms in 27/42 (64%), and both in 19/42 patients (45%). Limbic T2/fluid-attenuated inversion recovery signal hyperintensities were found in 26/46 patients (57%; unilateral: n = 22, bilateral: n = 4). Standard CSF studies were abnormal in 2/37 patients (5%). Neuronal Abs were confirmed in serum and/or CSF in 8/47 patients (17%) and were directed against neuronal cell-surface targets (leucine-rich glioma inactivated protein 1: n = 1, contactin-associated protein-2: n = 1, undetermined target: n = 3) or glutamic acid decarboxylase in its 65-kD isoform (n = 3, all with high titers). Compared to Ab-negative patients, those who harbored neuronal Abs were more likely to have uni- or bilateral mediotemporal MRI changes (8/8, 100% vs. 18/38, 47%; p = 0.01, Fisher's exact test)., Conclusions: In patients with temporal lobe seizures and additional limbic signs, 17% had neuronal Abs affirming ALE diagnosis. Mediotemporal MRI changes were found in all Ab-positive cases and had a positive likelihood ratio of 2.11 (95% confidence interval 1.51-2.95)., (© 2021 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)
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- 2022
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11. Overlapping GAD65-associated autoimmune neurological syndromes and type 1 diabetes.
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Ismail FS
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- Autoantibodies, Glutamate Decarboxylase, Humans, Syndrome, Autoimmune Diseases diagnosis, Autoimmune Diseases genetics, Connective Tissue Diseases, Diabetes Mellitus, Type 1
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- 2022
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12. GABA A Receptor Autoantibodies Decrease GABAergic Synaptic Transmission in the Hippocampal CA3 Network.
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Menke AF, Ismail FS, Dornmair K, Cerina M, Meuth SG, and Melzer N
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- Animals, Autoantibodies metabolism, Hashimoto Disease, Hippocampus metabolism, Humans, Mice, Mice, Inbred C57BL, Pyramidal Cells metabolism, Seizures metabolism, Synaptic Transmission, gamma-Aminobutyric Acid metabolism, Encephalitis metabolism, Receptors, GABA-A metabolism
- Abstract
Autoimmune encephalitis associated with antibodies (Abs) against α1, β3, and γ2 subunits of γ-aminobutyric acid receptor A (GABA
A R) represents a severe form of encephalitis with refractory seizures and status epilepticus. Reduction in inhibitory GABAergic synaptic activity is linked to dysfunction of neuronal networks, hyperexcitability, and seizures. The aim in this study was to investigate the direct pathogenic effect of a recombinant GABAA R autoantibody (rAb-IP2), derived from the cerebrospinal fluid (CSF) of a patient with autoimmune GABAA R encephalitis, on hippocampal CA1 and CA3 networks. Acute brain slices from C57BL/6 mice were incubated with rAb-IP2. The spontaneous synaptic GABAergic transmission was measured using electrophysiological recordings in voltage-clamp mode. The GABAA R autoantibody rAb-IP2 reduced inhibitory postsynaptic signaling in the hippocampal CA1 pyramidal neurons with regard to the number of spontaneous inhibitory postsynaptic currents (sIPSCs) but did not affect their amplitude. In the hippocampal CA3 network, decreased number and amplitude of sIPSCs were detected, leading to decreased GABAergic synaptic transmission. Immunohistochemical staining confirmed the rAb-IP2 bound to hippocampal tissue. These findings suggest that GABAA R autoantibodies exert direct functional effects on both hippocampal CA1 and CA3 pyramidal neurons and play a crucial role in seizure generation in GABAA R autoimmune encephalitis.- Published
- 2022
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13. Effects of Lamotrigine and Topiramate on Glial Properties in an Astrocyte-Microglia Co-Culture Model of Inflammation.
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Faustmann TJ, Corvace F, Faustmann PM, and Ismail FS
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- Animals, Astrocytes metabolism, Coculture Techniques, Connexin 43 metabolism, Cytokines metabolism, Inflammation metabolism, Lamotrigine metabolism, Lamotrigine pharmacology, Lamotrigine therapeutic use, Microglia, Rats, Topiramate pharmacology, Topiramate therapeutic use, Tumor Necrosis Factor-alpha, Anticonvulsants pharmacology, Anticonvulsants therapeutic use, Epilepsy
- Abstract
Background: Astrocytes and microglia are involved in the pathophysiology of epilepsy and bipolar disorder with a link to inflammation. We aimed to investigate the effects of the antiepileptic and mood-stabilizing drugs lamotrigine (LTG) and topiramate (TPM) on glial viability, microglial activation, cytokine release, and expression of gap-junctional protein connexin 43 (Cx43) in different set-ups of an in vitro astrocyte-microglia co-culture model of inflammation., Methods: Primary rat co-cultures of astrocytes containing 5% (M5, representing "physiological" conditions) or 30% (M30, representing "pathological, inflammatory" conditions) of microglia were treated with different concentrations of LTG and TPM for 24 hours. An 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to measure the glial cell viability. The microglial activation state was analyzed by immunocytochemistry. The pro-inflammatory tumor necrosis factor-α (TNF-α) and anti-inflammatory transforming growth factor-ß1 (TGF-ß1) cytokine levels were measured by enzyme-linked immunosorbent assay. The astroglial Cx43 expression was quantified by western blot., Results: A significant reduction of the glial cell viability after incubation with LTG or TPM was observed in a concentration-dependent manner under all conditions. LTG caused no significant alterations of the microglial phenotypes. Under pathological conditions, TPM led to a significant concentration-dependent reduction of microglial activation. This correlated with increased astroglial Cx43 expression. TNF-α levels were not affected by LTG and TPM. Treatment with higher concentrations of LTG, but not with TPM, led to a significant increase in TGF-ß1 levels in M5 and M30 co-cultures., Conclusions: Despite the possible glial toxicity of LTG and TPM, both drugs reduced inflammatory activity, suggesting potential positive effects on the neuroinflammatory components of the pathogenesis of epilepsy and bipolar disorder., (© The Author(s) 2021. Published by Oxford University Press on behalf of CINP.)
- Published
- 2022
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14. Anti-inflammatory properties of lacosamide in an astrocyte-microglia co-culture model of inflammation.
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Corvace F, Faustmann TJ, Faustmann PM, and Ismail FS
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- Animals, Rats, Inflammation drug therapy, Inflammation pathology, Inflammation metabolism, Cell Communication drug effects, Rats, Wistar, Gap Junctions drug effects, Gap Junctions metabolism, Anticonvulsants pharmacology, Cells, Cultured, Astrocytes drug effects, Astrocytes metabolism, Astrocytes pathology, Coculture Techniques, Lacosamide pharmacology, Microglia drug effects, Microglia metabolism, Microglia pathology, Cell Survival drug effects, Anti-Inflammatory Agents pharmacology, Connexin 43 metabolism
- Abstract
Purpose: Understanding the effects of antiepileptic drugs on glial cells and glia-mediated inflammation is a new approach to future treatment of epilepsy. Little is known about direct effects of the antiepileptic drug lacosamide (LCM) on glial cells. Therefore, we aimed to study the LCM effects on glial viability, microglial activation, expression of gap-junctional (GJ) protein Cx43 as well as intercellular communication in an in vitro astrocyte-microglia co-culture model of inflammation., Methods: Primary rat astrocytes co-cultures containing 5% (M5, "physiological" conditions) or 30% (M30, "pathological inflammatory" conditions) of microglia were treated with different concentrations of LCM [5, 15, 30, and 90 μg/ml] for 24 h. Glial cell viability was measured by MTT assay. Immunocytochemistry was performed to analyze the microglial activation state. Western blot analysis was used to quantify the astroglial Cx43 expression. The GJ cell communication was studied via Scrape Loading., Results: A concentration-dependent incubation with LCM did not affect the glial cell viability both under physiological and pathological conditions. LCM induced a significant concentration-dependent decrease of activated microglia with parallel increase of ramified microglia under pathological inflammatory conditions. This correlated with an increase in astroglial Cx43 expression. Nevertheless, the functional coupling via GJs was significantly reduced after incubation with LCM., Conclusion: LCM has not shown effects on the glial cell viability. The reduced GJ coupling by LCM could be related to its anti-epileptic activity. The anti-inflammatory glial features of LCM with inhibition of microglial activation under inflammatory conditions support beneficial role in epilepsy associated with neuroinflammation., (Copyright © 2021 Elsevier B.V. All rights reserved.)
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- 2022
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15. Pharmacological Investigations in Glia Culture Model of Inflammation.
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Ismail FS, Corvace F, Faustmann PM, and Faustmann TJ
- Abstract
Astrocytes and microglia are the main cell population besides neurons in the central nervous system (CNS). Astrocytes support the neuronal network via maintenance of transmitter and ion homeostasis. They are part of the tripartite synapse, composed of pre- and postsynaptic neurons and perisynaptic astrocytic processes as a functional unit. There is an increasing evidence that astroglia are involved in the pathophysiology of CNS disorders such as epilepsy, autoimmune CNS diseases or neuropsychiatric disorders, especially with regard to glia-mediated inflammation. In addition to astrocytes, investigations on microglial cells, the main immune cells of the CNS, offer a whole network approach leading to better understanding of non-neuronal cells and their pathological role in CNS diseases and treatment. An in vitro astrocyte-microglia co-culture model of inflammation was developed by Faustmann et al. (2003), which allows to study the endogenous inflammatory reaction and the cytokine expression under drugs in a differentiated manner. Commonly used antiepileptic drugs (e.g., levetiracetam, valproic acid, carbamazepine, phenytoin, and gabapentin), immunomodulatory drugs (e.g., dexamethasone and interferon-beta), hormones and psychotropic drugs (e.g., venlafaxine) were already investigated, contributing to better understanding mechanisms of actions of CNS drugs and their pro- or anti-inflammatory properties concerning glial cells. Furthermore, the effects of drugs on glial cell viability, proliferation and astrocytic network were demonstrated. The in vitro astrocyte-microglia co-culture model of inflammation proved to be suitable as unique in vitro model for pharmacological investigations on astrocytes and microglia with future potential (e.g., cancer drugs, antidementia drugs, and toxicologic studies)., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Ismail, Corvace, Faustmann and Faustmann.)
- Published
- 2021
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16. The role of dendritic cells and their interactions in the pathogenesis of antibody-associated autoimmune encephalitis.
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Ismail FS, Meuth SG, and Melzer N
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- Animals, Autoimmune Diseases pathology, Encephalitis pathology, Humans, Neuroinflammatory Diseases pathology, Autoimmune Diseases immunology, Dendritic Cells immunology, Dendritic Cells pathology, Encephalitis immunology, Neuroinflammatory Diseases immunology
- Abstract
Autoimmune encephalitis (AE) is an inflammatory brain disease which is frequently associated with antibodies (Abs) against cell-surface, synaptic or intracellular neuronal proteins. There is increasing evidence that dendritic cells (DCs) are implicated as key modulators in keeping the balance between immune response and tolerance in the CNS. Migratory features of DCs to and from the brain are linked to initiating and maintaining of neuroinflammation. Genetic polymorphisms together with other triggers such as systemic or cerebral viral infection, or systemic malignancies could contribute to the dysbalance of "regulatory" and "encephalitogenic" DCs with subsequent dysregulated T and B cell reactions in AE. Novel in vivo models with implantation of mature DCs containing neuronal antigens could help to study the pathogenesis and perhaps to understand the origin of AE. Investigations of DCs in human blood, lymphoid tissues, CSF, and brain parenchyma of patients with AE are necessary to deepen our knowledge about the complex interactions between DCs, T and B cells during neuroinflammation in AE. This can support developing new therapy strategies., (© 2021. The Author(s).)
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- 2021
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17. A broad spectrum of posterior reversible encephalopathy syndrome - a case series with clinical and paraclinical characterisation, and histopathological findings.
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Ismail FS, van de Nes J, and Kleffner I
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- Adolescent, Adult, Aged, Endothelial Cells, Female, Humans, Magnetic Resonance Imaging, Middle Aged, Retrospective Studies, Young Adult, Brain Diseases, Posterior Leukoencephalopathy Syndrome diagnostic imaging
- Abstract
Background: Posterior reversible encephalopathy syndrome (PRES) is clinical-neuroradiologically defined and potentially reversible, so there are limited data about histopathological findings. We aimed to describe the clinical and paraclinical features of patients with PRES with regard to its reversibility., Methods: This retrospective case series encompasses 15 PRES cases out of 1300 evaluated patients from a single German center between January 1, 2010, and June 15, 2020. PRES was established according to the diagnostic criteria as proposed by the Berlin PRES Study 2012. One of the cases studied was subject to brain autopsy., Results: From the 15 patients studied (median age 53 years, range 17-73; 11 female), 67 % presented with epileptic seizures, 40 % suffered from encephalopathy with reduced consciousness and 53 % developed delirium, while 47 % had headache and visual disturbances. Subcortical brain MRI abnormalities related to PRES were observed in all patients. One patient developed spinal ischemia and another Guillain-Barré syndrome in addition to PRES. Hypertensive blood pressure was the main underlying/trigger condition in all patients. Clinical symptoms and MRI changes were not reversible in 42 %, even progressive in 3 out of these 5 patients. Median time from symptom onset to diagnosis in these non-reversible cases was 7 days (range 0-13), while the median delay in diagnosis in the reversible group was 1 day (range 0-3). Cerebellar/brain stem involvement and status epilepticus were more frequently in patients with non-reversible disease course. Mortality due to PRES occurred in 13 % of these patients. Neuropathological examination of the brain of a 57-year-old female patient revealed major leukencephalopathic changes, fibrinoid necrosis of endothelial cells and fresh petechial hemorrhages in accordance with PRES., Conclusions: Our case series demonstrates that PRES was not reversible in 42 % of the studied patients. Delay in diagnosis seems to contribute to limited reversibility and poor outcome., (© 2021. The Author(s).)
- Published
- 2021
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- View/download PDF
18. Experimental investigations of antiepileptic drugs in astrocytes-microglia co-cultures suggest possible protective effects on astrocytes during early epileptogenesis.
- Author
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Ismail FS and Faustmann PM
- Subjects
- Anticonvulsants pharmacology, Anticonvulsants therapeutic use, Coculture Techniques, Neuroglia, Astrocytes, Microglia
- Published
- 2021
- Full Text
- View/download PDF
19. Correction to: Routine diagnostics for neural antibodies, clinical correlates, treatment and functional outcome.
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Bien CG, Bien CI, Onugoren MD, De Simoni D, Eigler V, Haensch CA, Holtkamp M, Ismail FS, Kurthen M, Melzer N, Mayer K, von Podewils F, Rauschka H, Rossetti AO, Schäbitz WR, Simova O, Witt K, Höftberger R, and May TW
- Published
- 2021
- Full Text
- View/download PDF
20. Support Vector Regression Modelling of an Aerobic Granular Sludge in Sequential Batch Reactor.
- Author
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Ahmad Yasmin NS, Abdul Wahab N, Ismail FS, Musa MJ, Halim MHA, and Anuar AN
- Abstract
Support vector regression (SVR) models have been designed to predict the concentration of chemical oxygen demand in sequential batch reactors under high temperatures. The complex internal interaction between the sludge characteristics and their influent were used to develop the models. The prediction becomes harder when dealing with a limited dataset due to the limitation of the experimental works. A radial basis function algorithm with selected kernel parameters of cost and gamma was used to developed SVR models. The kernel parameters were selected by using a grid search method and were further optimized by using particle swarm optimization and genetic algorithm. The SVR models were then compared with an artificial neural network. The prediction results R
2 were within >90% for all predicted concentration of COD. The results showed the potential of SVR for simulating the complex aerobic granulation process and providing an excellent tool to help predict the behaviour in aerobic granular reactors of wastewater treatment.- Published
- 2021
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- View/download PDF
21. Impacts of Autonomous Vehicles on Greenhouse Gas Emissions-Positive or Negative?
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Massar M, Reza I, Rahman SM, Abdullah SMH, Jamal A, and Al-Ismail FS
- Subjects
- Aged, Greenhouse Effect, Humans, Travel, Vehicle Emissions analysis, Automobile Driving, Greenhouse Gases analysis
- Abstract
The potential effects of autonomous vehicles (AVs) on greenhouse gas (GHG) emissions are uncertain, although numerous studies have been conducted to evaluate the impact. This paper aims to synthesize and review all the literature regarding the topic in a systematic manner to eliminate the bias and provide an overall insight, while incorporating some statistical analysis to provide an interval estimate of these studies. This paper addressed the effect of the positive and negative impacts reported in the literature in two categories of AVs: partial automation and full automation. The positive impacts represented in AVs' possibility to reduce GHG emission can be attributed to some factors, including eco-driving, eco traffic signal, platooning, and less hunting for parking. The increase in vehicle mile travel (VMT) due to (i) modal shift to AVs by captive passengers, including elderly and disabled people and (ii) easier travel compared to other modes will contribute to raising the GHG emissions. The result shows that eco-driving and platooning have the most significant contribution to reducing GHG emissions by 35%. On the other side, easier travel and faster travel significantly contribute to the increase of GHG emissions by 41.24%. Study findings reveal that the positive emission changes may not be realized at a lower AV penetration rate, where the maximum emission reduction might take place within 60-80% of AV penetration into the network.
- Published
- 2021
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- View/download PDF
22. Ammonia induced microglia activation was associated with limited effects on connexin 43 and aquaporin 4 expression in an astrocyte-microglia co-culture model.
- Author
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Ismail FS, Faustmann TJ, Corvace F, Tsvetanova A, Moinfar Z, and Faustmann PM
- Subjects
- Animals, Astrocytes metabolism, Cell Survival drug effects, Cells, Cultured, Coculture Techniques, Hepatic Encephalopathy metabolism, Rats, Ammonium Chloride toxicity, Aquaporin 4 metabolism, Connexin 43 metabolism, Microglia drug effects, Microglia metabolism
- Abstract
Background: Hepatic encephalopathy (HE) is a neurological complication resulting from acute or chronic liver disease. Hyperammonemia leading to astrocyte swelling and cerebral edema in combination with neuroinflammation including microglia activation, mainly contribute to the pathogenesis of HE. However, little is known about microglia and their inflammatory response, as well as their influence on astrocytic channels and astrocyte swelling under hyperammonemia., Objective: To investigate the effects of ammonia on the microglial activation and morphology in different set-ups of an in vitro astrocyte-microglia co-culture model. Further, potential effects on glial viability, connexin 43 (Cx43) and aquaporin 4 (AQP4) expression were tested., Methods: Primary rat glial co-cultures of astrocytes containing 5% (M5, representing "physiological" conditions) or 30% (M30, representing "pathological" conditions) of microglia were incubated with 3 mM, 5 mM, 10 mM and 20 mM ammonium chloride (NH4Cl) for 6 h and 24 h in order to mimic the conditions of HE. An MTT assay was performed to measure the viability, proliferation and cytotoxicity of cells. The microglial phenotypes were analyzed by immunocytochemistry. The expression of Cx43 and AQP4 were quantified by immunoblot analysis., Results: A significant reduction of glial viability was observed in M30 co-cultures after incubation with 20 mM NH4Cl for 6 h, whereas in M5 co-cultures the viability remained unchanged. Microglial activation was detected by immunocytochemistry after incubation with 3 mM, 5 mM and 10 mM NH4Cl for 6 h and 24 h in M5 as well as in M30 co-cultures. The Cx43 expression was slightly increased in M30 co-cultures after 6 h incubation with 5 mM NH4Cl. Also, the AQP4 expression was slightly increased only in M5 co-cultures treated with 10 mM NH4Cl for 6 h. Under the other conditions, Cx43 and AQP4 expression was not affected by NH4Cl., Conclusions: The novel aspect of our study was the significant microglial activation and decrease of viability after NH4Cl incubation in different set-ups of an in vitro astrocyte-microglia co-culture model, contributing to better understanding of pathophysiological mechanisms of HE. Hyperammonemia led to limited effects on Cx43 and AQP4 expression, the relevance of these minimal changes should be viewed with caution.
- Published
- 2021
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- View/download PDF
23. Routine diagnostics for neural antibodies, clinical correlates, treatment and functional outcome.
- Author
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Bien CG, Bien CI, Dogan Onugoren M, De Simoni D, Eigler V, Haensch CA, Holtkamp M, Ismail FS, Kurthen M, Melzer N, Mayer K, von Podewils F, Rauschka H, Rossetti AO, Schäbitz WR, Simova O, Witt K, Höftberger R, and May TW
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Autoimmune Diseases of the Nervous System blood, Autoimmune Diseases of the Nervous System cerebrospinal fluid, Autoimmune Diseases of the Nervous System immunology, Child, Child, Preschool, Female, HEK293 Cells, Humans, Infant, Male, Mental Disorders blood, Mental Disorders cerebrospinal fluid, Mental Disorders immunology, Middle Aged, Reproducibility of Results, Retrospective Studies, Young Adult, Autoantibodies analysis, Autoantibodies blood, Autoantibodies cerebrospinal fluid, Autoimmune Diseases of the Nervous System diagnosis, Diagnostic Techniques, Neurological standards, Glutamate Decarboxylase immunology, Immunologic Tests standards, Intracellular Signaling Peptides and Proteins immunology, Membrane Proteins immunology, Mental Disorders diagnosis, Nerve Tissue Proteins immunology, Neuropil immunology, Potassium Channels, Voltage-Gated immunology, Receptors, AMPA immunology, Receptors, GABA-B immunology, Receptors, Glycine immunology, Receptors, N-Methyl-D-Aspartate immunology
- Abstract
Objective: To determine frequencies, interlaboratory reproducibility, clinical ratings, and prognostic implications of neural antibodies in a routine laboratory setting in patients with suspected neuropsychiatric autoimmune conditions., Methods: Earliest available samples from 10,919 patients were tested for a broad panel of neural antibodies. Sera that reacted with leucine-rich glioma-inactivated protein 1 (LGI1), contactin-associated protein-2 (CASPR2), or the voltage-gated potassium channel (VGKC) complex were retested for LGI1 and CASPR2 antibodies by another laboratory. Physicians in charge of patients with positive antibody results retrospectively reported on clinical, treatment, and outcome parameters., Results: Positive results were obtained for 576 patients (5.3%). Median disease duration was 6 months (interquartile range 0.6-46 months). In most patients, antibodies were detected both in CSF and serum. However, in 16 (28%) patients with N-methyl-D-aspartate receptor (NMDAR) antibodies, this diagnosis could be made only in cerebrospinal fluid (CSF). The two laboratories agreed largely on LGI1 and CASPR2 antibody diagnoses (κ = 0.95). The clinicians (413 responses, 71.7%) rated two-thirds of the antibody-positive patients as autoimmune. Antibodies against the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), NMDAR (CSF or high serum titer), γ-aminobutyric acid-B receptor (GABABR), and LGI1 had ≥ 90% positive ratings, whereas antibodies against the glycine receptor, VGKC complex, or otherwise unspecified neuropil had ≤ 40% positive ratings. Of the patients with surface antibodies, 64% improved after ≥ 3 months, mostly with ≥ 1 immunotherapy intervention., Conclusions: This novel approach starting from routine diagnostics in a dedicated laboratory provides reliable and useful results with therapeutic implications. Counseling should consider clinical presentation, demographic features, and antibody titers of the individual patient.
- Published
- 2020
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24. Correction to: Routine diagnostics for neural antibodies, clinical correlates, treatment and functional outcome.
- Author
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Bien CG, Bien CI, Dogan Onugoren M, De Simoni D, Eigler V, Haensch CA, Holtkamp M, Ismail FS, Kurthen M, Melzer N, Mayer K, von Podewils F, Rauschka H, Rossetti AO, Schäbitz WR, Simova O, Witt K, Höftberger R, and May TW
- Abstract
The original version of this article unfortunately contained a mistake.
- Published
- 2020
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- View/download PDF
25. Astrocytes and their potential role in anti-NMDA receptor encephalitis.
- Author
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Ismail FS and Faustmann PM
- Subjects
- Animals, Astrocytes, Cells, Cultured, Mice, Rats, Receptors, N-Methyl-D-Aspartate, Anti-N-Methyl-D-Aspartate Receptor Encephalitis, Hashimoto Disease
- Abstract
The N-methyl-d-aspartate receptor (NMDAR) encephalitis is the most common form of autoimmune encephalitis. Antibodies against the GluN1 subunit of the NMDAR showed in primary cultures of rat hippocampal neurons and in a mouse model pathogenic effects including cross-linking and internalization of the target receptors (NMDAR). Several studies demonstrated that not only neurons, but also astrocytes express functional NMDA receptors including GluN1 subunit. It is conceivable that the pathogenic antibodies against the NMDAR causing the anti-NMDAR encephalitis affect not only the neuronal receptors, but also the NMDAR on astrocytes. We hypothesize that antibodies against NMDAR can lead to cross-linking and internalization of the target receptors in astrocytes similar to neurons with disruption of the calcium release within the astrocytes and consequently blocking release of inhibitory gliotransmitters. Further, we assume influence on expression of aquaporin 4 channels and gap-junctional communication due to modification of the astrocytic NMDAR. The disruption of these interactions and dysbalance could result in impairment of CNS homeostasis and co-determine the severity of clinical disease manisfestation and recovery., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)
- Published
- 2020
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- View/download PDF
26. Impact of Resolution Recovery in Quantitative 99m Tc SPECT/CT Cardiac Phantom Studies.
- Author
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Ismail FS and Mansor S
- Subjects
- Humans, Image Processing, Computer-Assisted, Heart diagnostic imaging, Phantoms, Imaging, Single Photon Emission Computed Tomography Computed Tomography methods
- Abstract
Background: The aim of this study was to validate the quantitative accuracy of single photon emission computed tomography with computed tomography (SPECT/CT) images in cardiac phantom studies. The study was performed by assessing the effect of resolution recovery (RR) when using half-time of imaging acquisition in cardiac phantom., Methods: The SPECT/CT images of the anthropomorphic phantom with a cardiac insert, liver, lung, and spine were acquired using the GE Discovery (NM/CT 670) SPECT/CT system. Different concentration activity ratios for different organ (10:10:1:0, cardiac:liver:background:lung) regions were acquired by using full- and half-time protocols for 64
3 and 1283 voxel sizes that were reconstructed using filtered back projection (FBP) method and 3D ordered subset expectation maximization (3D-OSEM). Attenuation correction and scatter correction were applied to both reconstructions, whereas the RR only can be applied for 3D-OSEM. The data were analyzed and reported in terms of absolute recovery coefficient percentage between the cardiac insert and background activity concentration. Another parameter used to assess the quantitative accuracy for defect region was the relative error percentage., Results: The result of recovery coefficient percentage shows that the 3D-OSEM reconstruction with the RR gives the highest percentage estimation accuracy of 70% of activity recovery in the cardiac phantom wall compared with FBP (10.6%). The relative error percentage for reconstructed SPECT/CT images using 3D-OSEM reconstruction with RR shows the least error compared with FBP (21% vs. 45.1%) both in the full-and half-time acquisition of images with a larger number of matrix size used., Conclusions: 3D-OSEM reconstruction with the RR is beneficial in giving better quantitative evaluation with a good resolution myocardial perfusion image. To accomplish this, a larger matrix size is required for 3D-OSEM reconstruction with the RR and it demonstrated an improvement in image resolution and increased quantitative accuracy of the final reconstructed SPECT/CT images., (Copyright © 2019. Published by Elsevier Inc.)- Published
- 2019
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- View/download PDF
27. [Episodic central hypopnea and hypotension : Caused by bleeding into a craniocervical ependymoma].
- Author
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Ismail FS, Schlegel U, Kowoll A, and Skodda S
- Subjects
- Aged, Female, Humans, Treatment Outcome, Apnea etiology, Ependymoma complications, Ependymoma diagnostic imaging, Ependymoma pathology, Ependymoma therapy, Hypotension etiology
- Published
- 2018
- Full Text
- View/download PDF
28. Latent autoimmune diabetes and limbic encephalitis with antibodies against glutamic acid decarboxylase.
- Author
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Popkirov S, Sebastian S, Ismail FS, and Wellmer J
- Subjects
- Diabetes Mellitus, Type 1 blood, Diabetes Mellitus, Type 1 pathology, Female, Glutamate Decarboxylase blood, Humans, Limbic Encephalitis blood, Limbic Encephalitis pathology, Middle Aged, Prognosis, Autoantibodies blood, Diabetes Mellitus, Type 1 immunology, Glucose Intolerance immunology, Glutamate Decarboxylase immunology, Limbic Encephalitis immunology
- Published
- 2018
- Full Text
- View/download PDF
29. Progressive hippocampal sclerosis after viral encephalitis: Potential role of NMDA receptor antibodies.
- Author
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Popkirov S, Ismail FS, Grönheit W, Kapauer M, Wellmer J, and Bien CG
- Subjects
- Adolescent, Adult, Autoantigens immunology, Child, Encephalitis, Herpes Simplex complications, Encephalitis, Varicella Zoster complications, Female, Hippocampus pathology, Humans, Middle Aged, Retrospective Studies, Sclerosis immunology, Autoantibodies immunology, Encephalitis, Herpes Simplex immunology, Encephalitis, Varicella Zoster immunology, Epilepsy immunology, Receptors, N-Methyl-D-Aspartate immunology
- Abstract
Purpose: Survivors of viral encephalitis can develop refractory epilepsy and hippocampal sclerosis. Both the initial infectious insult and the secondary effects of recurrent seizures have been implicated in chronic disease progression. Recently, post-infectious autoimmunity, involved in acute relapses, has also been proposed as a pathomechanism for chronic disease progression. Our case series suggests a potential role of antibodies against the N-methyl-d-aspartate receptor (NMDAR) in chronic inflammatory disease beyond acute manifestations., Methods: Retrospective chart review of four patients with epilepsy, hippocampal sclerosis following viral encephalitis and NMDAR-antibodies in CSF., Results: The four patients were female, developed hippocampal sclerosis (in 3/4 in a step-wise progression) after Herpes simplex or Varicella zoster virus encephalitis and harboured immunoglobulin G antibodies against the NMDAR in their CSF. Two patients were treated with short-term immunosuppression but did not benefit., Conclusion: This case series presents the first tentative evidence in support of chronic autoimmune inflammation driving disease progression after viral encephalitis beyond the known acute immune-mediated relapses. The anecdotal nature of the data does not, however, permit conclusive judgement on causality. Should our findings be replicated in larger cohorts, the treatment of post-infectious epilepsy could potentially be expanded to include immunosuppressive strategies in antibody-positive cases., (Copyright © 2017 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2017
- Full Text
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30. Relapsing polychondritis as an unusual cause of multiple cranial nerve palsies-A Case report.
- Author
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Ismail FS, Enzi B, Boy C, Kowoll A, Eyding J, and Schlegel U
- Subjects
- Anti-Inflammatory Agents therapeutic use, Cranial Nerve Diseases drug therapy, Female, Humans, Methylprednisolone therapeutic use, Middle Aged, Polychondritis, Relapsing drug therapy, Cranial Nerve Diseases diagnostic imaging, Cranial Nerve Diseases etiology, Polychondritis, Relapsing complications, Polychondritis, Relapsing diagnostic imaging
- Published
- 2017
- Full Text
- View/download PDF
31. Dexamethasone and levetiracetam reduce hetero-cellular gap-junctional coupling between F98 glioma cells and glial cells in vitro.
- Author
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Ismail FS, Moinfar Z, Prochnow N, Dambach H, Hinkerohe D, Haase CG, Förster E, and Faustmann PM
- Subjects
- Animals, Antineoplastic Agents therapeutic use, Astrocytes physiology, Cell Line, Tumor, Connexin 43 metabolism, Connexins metabolism, Dexamethasone therapeutic use, Glioma drug therapy, In Vitro Techniques, Levetiracetam, Microglia physiology, Neuroglia drug effects, Piracetam pharmacology, Piracetam therapeutic use, Rats, Tumor Cells, Cultured, Gap Junction beta-1 Protein, Gap Junction delta-2 Protein, Antineoplastic Agents pharmacology, Cell Communication drug effects, Dexamethasone pharmacology, Gap Junctions drug effects, Glioma physiopathology, Neuroglia physiology, Piracetam analogs & derivatives
- Abstract
Gap junctions (GJs) in astrocytes and glioma cells are important channels for cell-to-cell communication that contribute to homo- and heterocellular coupling. According to recent studies, heterocellular gap-junctional communication (H-GJC) between glioma cells and their surrounding environment enhances glioma progression. Therefore, we developed a new in vitro model to examine H-GJC between glioma cells, astrocytes and microglia. Consequently, F98 rat glioma cells were double-labeled with GJ-impermeable (CM-DiI) and GJ-permeable dye (calcein AM) and were seeded on unlabeled astrocyte-microglia co-cultures. Dual whole cell voltage clamp recordings were carried out on selected cell pairs to characterize the functional properties of H-GJC in vitro. The expression of four types of connexins (Cxs), including Cx32, Cx36, Cx43 and Cx45, and microglial phenotypes were analyzed by immunocytochemistry. The H-GJC between glioma cells and astrocytes/microglia increased after a longer incubation period with a higher number of glioma cells. We provided evidence for the direct GJ coupling of microglia and glioma cells under native in vitro conditions. In addition, we exploited this model to evaluate H-GJC after incubation with levetiracetam (LEV) and/or dexamethasone (DEX). Previous in vitro studies suggest that LEV and DEX are frequently used to control seizure and edema in glioma. Our findings showed that LEV and/or DEX decrease the number of heterocellular coupled cells significantly. In conclusion, our newly developed model demonstrated H-GJC between glioma cells and both astrocytes and microglia. The reduced H-GJC by LEV and DEX suggests a potential effect of both drugs on glioma progression.
- Published
- 2017
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32. Faciobrachio-crural dystonic seizures in LGI1 limbic encephalitis: A treatable cause of falls.
- Author
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Ismail FS, Popkirov S, Wellmer J, and Grönheit W
- Published
- 2015
- Full Text
- View/download PDF
33. Incorporation of Si and SiO(x) into diamond-like carbon films: impact on surface properties and osteoblast adhesion.
- Author
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Randeniya LK, Bendavid A, Martin PJ, Amin MS, Preston EW, Magdon Ismail FS, and Coe S
- Subjects
- Cell Adhesion drug effects, Humans, Materials Testing, Mechanical Phenomena drug effects, Osteoblasts ultrastructure, Spectrum Analysis, Surface Properties drug effects, Thermodynamics, Diamond pharmacology, Osteoblasts cytology, Osteoblasts drug effects, Silicon pharmacology, Silicon Dioxide pharmacology
- Abstract
The interaction of human osteoblast cells with diamond-like carbon films incorporating silicon and silicon oxide (SiO(x), 1 < or = x < or = 1.5) and synthesized using the direct-current plasma-activated chemical vapour deposition method was investigated. Cell culture studies were performed for films with Si contents ranging from approximately 4 at.% to 15 at.%. Substantial differences between Si-incorporated and SiO(x)-incorporated films were found for the bonding environments of Si atoms and the hybridization of underlying carbon structures. However, osteoblast-attachment studies did not show statistically significant trends in properties of cell growth (count, area and morphology) that can be attributed either to the Si content of the films or to the chemical structure of the films. The surface energy decreased by 40% as the Si content of the SiO(x) incorporated DLC films increased to 13 at.%. The cell adhesion properties however did not change in response to lowering of the surface energy. The incorporation of both Si and SiO(x) leads to a beneficial reduction in the residual stress of the films. The average roughness of the films increases and the hardness decreases when Si and SiO(x) are added to DLC films. The impact of these changes for load-bearing biomedical applications can be determined only by carefully controlled experiments using anatomic simulators.
- Published
- 2009
- Full Text
- View/download PDF
34. The influence of surface chemistry and topography on the contact guidance of MG63 osteoblast cells.
- Author
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Ismail FS, Rohanizadeh R, Atwa S, Mason RS, Ruys AJ, Martin PJ, and Bendavid A
- Subjects
- Biocompatible Materials chemistry, Carbon chemistry, Cell Adhesion physiology, Cell Line, Cell Survival, Humans, In Vitro Techniques, Materials Testing, Microscopy, Electron, Scanning, Silicon, Surface Properties, Titanium chemistry, Coated Materials, Biocompatible chemistry, Osteoblasts cytology, Osteoblasts physiology
- Abstract
The purpose of the present study was to determine in vitro the effects of different surface topographies and chemistries of commercially pure titanium (cpTi) and diamond-like carbon (DLC) surfaces on osteoblast growth and attachment. Microgrooves (widths of 2, 4, 8 and 10 microm and a depth of 1.5-2 microm) were patterned onto silicon (Si) substrates using microlithography and reactive ion etching. The Si substrates were subsequently vapor coated with either cpTi or DLC coatings. All surfaces were characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and contact angle measurements. Using the MG63 Osteoblast-Like cell line, we determined cell viability, adhesion, and morphology on different substrates over a 3 day culture period. The results showed cpTi surfaces to be significantly more hydrophilic than DLC for groove sizes larger than 2 microm. Cell contact guidance was observed for all grooved samples in comparison to the unpatterned controls. The cell viability tests indicated a significantly greater cell number for 8 and 10 microm grooves on cpTi surfaces compared to other groove sizes. The cell adhesion study showed that the smaller groove sizes, as well as the unpatterned control groups, displayed better cell adhesion to the substrate.
- Published
- 2007
- Full Text
- View/download PDF
35. Mechanical properties across hypomineralized/hypoplastic enamel of first permanent molar teeth.
- Author
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Mahoney E, Ismail FS, Kilpatrick N, and Swain M
- Subjects
- Crystallography, Dentin physiopathology, Elasticity, Hardness, Humans, Microscopy, Electron, Scanning, Molar physiopathology, Stress, Mechanical, Tooth Cervix physiopathology, Dental Enamel physiopathology, Dental Enamel Hypoplasia physiopathology, Tooth Demineralization physiopathology
- Abstract
The aims of the present study were to investigate the mechanical properties of first permanent molars affected with enamel hypomineralization or hypoplasia, and to describe the appearance of these lesions under scanning electron microscopy. Eight first permanent molar test teeth and two unaffected premolars (controls) were enclosed in resin, then sectioned axially and polished. The hardness and modulus of elasticity was determined from a single array of indentations made parallel to the amelo-dentinal junction using an Ultra-Micro-Indentation system. The teeth were then examined using the scanning electron microscope. The mechanical properties of the test teeth in the unaffected cervical region (hardness and modulus range, 2.03-4.99 GPa and 50.39-96.87 GPa, respectively) were similar to those of the control enamel (hardness and modulus range, 2.71-4.15 GPa and 62.06-95.77 GPa, respectively). Between the unaffected cervical enamel and the hypomineralized region there was a transitional area of 500-600 microm where the mechanical properties in the experimental teeth decreased linearly. The mechanical properties of the hypomineralized region of each experimental tooth were significantly lower than those of the control or cervical regions (hardness and modulus range, 0.07-1.74 GPa and 3.26-40.96 GPa, respectively). The scanning electron microscopy views revealed disorganized enamel with poorly demarcated prism boundaries in the affected regions. In conclusion, the hardness and modulus of elasticity of hypomineralized enamel in first permanent molars is significantly less than in unaffected areas of the same tooth. The reason for this is unclear but may be related to the lack of organization of the enamel crystals., (Copyright Eur J Oral Sci, 2004.)
- Published
- 2004
- Full Text
- View/download PDF
36. Mechanical properties and microstructure of hypomineralised enamel of permanent teeth.
- Author
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Mahoney EK, Rohanizadeh R, Ismail FS, Kilpatrick NM, and Swain MV
- Subjects
- Absorptiometry, Photon, Dental Enamel chemistry, Dental Enamel Hypoplasia, Dentin, Electrons, Humans, Image Processing, Computer-Assisted, Microscopy, Electron, Scanning, Molar chemistry, Scattering, Radiation, Stress, Mechanical, Temperature, Tensile Strength, Tooth Calcification, X-Ray Diffraction, Dental Enamel ultrastructure, Dentition, Permanent, Tooth ultrastructure
- Abstract
Isolated enamel defects are commonly seen in first permanent molar teeth but there has been little work on the physical and morphological composition of affected molars. The aim of this study was to determine the mechanical and morphological properties of hypomineralised first permanent molar teeth, utilising the Ultra-Micro-Indentation System (UMIS) and scanning electron microscope, respectively. Further investigations using Energy Dispersive X-ray Spectrometery (EDS), Back Scatter Electron (BSE) Imaging, and X-ray diffraction were employed to attempt to determine the chemical composition, mineral content and crystalline structure of the hypomineralised tissue, respectively, of eight first permanent molars with severe enamel hypomineralisation. The hardness and modulus of elasticity were found to be statistically significantly lower (0.53+/-0.31 and 14.49+/-7.56 GPa, respectively) than normal enamel (3.66+/-0.75 and 75.57+/-9.98 GPa, respectively). Although the fractured surface of the hypomineralised enamel was significantly more disorganised and the relative mineral content was reduced by approximately 5% in comparison to sound enamel, the mineral phase and Ca/P ratio was similar in hypomineralised and sound enamel. The dramatic reduction in the mechanical properties of first permanent molar teeth has ramifications when clinicians are choosing restorative materials to restore the defects. The reason for the dramatic reduction in mechanical properties of hypomineralised first permanent molar teeth is at present unknown.
- Published
- 2004
- Full Text
- View/download PDF
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