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Nys M, Zarkadas E, Brams M, Mehregan A, Kambara K, Kool J, Casewell N, Bertrand D, Baenziger JE, Nury H, Ulens C. The molecular mechanism of snake short-chain alpha-neurotoxin binding to muscle-type nicotinic acetylcholine receptors. Biophys J 2023; 122:392a. [PMID: 36783996 DOI: 10.1016/j.bpj.2022.11.2141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Mieke Nys
- Laboratory of Structural Neurobiology, Katholieke Universiteit Leuven, Leuven, Belgium
| | | | - Marijke Brams
- Laboratory of Structural Neurobiology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Aujan Mehregan
- Laboratory of Structural Neurobiology, Katholieke Universiteit Leuven, Leuven, Belgium
| | | | - Jeroen Kool
- Amsterdam Institute of Molecular and Life Sciences Division of BioMolecular Analysis, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | | | | | - John E Baenziger
- Department of Biochemistry, University of Ottawa, Ottawa, ON, Canada
| | - Hugues Nury
- Institut de Biologie Structurale, Grenoble, France
| | - Chris Ulens
- Laboratory of Structural Neurobiology, Katholieke Universiteit Leuven, Leuven, Belgium
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Verbinnen I, Procknow SS, Lenaerts L, Reynhout S, Mehregan A, Ulens C, Janssens V, King KA. Clinical and molecular characteristics of a novel rare de novo variant in PPP2CA in a patient with a developmental disorder, autism, and epilepsy. Front Cell Dev Biol 2022; 10:1059938. [DOI: 10.3389/fcell.2022.1059938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Accepted: 11/08/2022] [Indexed: 12/03/2022] Open
Abstract
PP2A-related (neuro) developmental disorders are a family of genetic diseases caused by a heterozygous alteration in one of several genes encoding a subunit of type 2A protein phosphatases. Reported affected genes, so far, are PPP2R5D, encoding the PP2A regulatory B56δ subunit; PPP2R1A, encoding the scaffolding Aα subunit; and PPP2CA, encoding the catalytic Cα subunit—in that order of frequency. Patients with a pathogenic de novo mutation in one of these genes, in part, present with overlapping features, such as generalized hypotonia, intellectual and developmental delay, facial dysmorphologies, seizures, and autistic features, and, in part, with opposite features, e.g., smaller versus larger head sizes or normal versus absent corpus callosum. Molecular variant characterization has been consistent so far with loss-of-function or dominant-negative disease mechanisms for all three affected genes. Here, we present a case report of another PPP2CA-affected individual with a novel de novo missense variant, resulting in a one-amino acid substitution in the Cα subunit: p.Cys196Arg. Biochemical characterization of the variant revealed its pathogenicity, as it appeared severely catalytically impaired, showed mildly affected A subunit binding, and moderately decreased binding to B/B55, B”/PR72, and all B56 subunits, except B56γ1. Carboxy-terminal methylation appeared unaffected, as was binding to B”’/STRN3—all being consistent with a partial loss of function. Clinically, the girl presented with mild-to-moderate developmental delay, a full-scale IQ of 83, mild dysmorphic facial features, tonic–clonic seizures, and autistic behaviors. Brain MRI appeared normal. We conclude that this individual falls within the milder end of the clinical and molecular spectrum of previously reported PPP2CA cases.
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Nys M, Zarkadas E, Brams M, Mehregan A, Kambara K, Kool J, Casewell NR, Bertrand D, Baenziger JE, Nury H, Ulens C. The molecular mechanism of snake short-chain α-neurotoxin binding to muscle-type nicotinic acetylcholine receptors. Nat Commun 2022; 13:4543. [PMID: 35927270 PMCID: PMC9352773 DOI: 10.1038/s41467-022-32174-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 07/20/2022] [Indexed: 11/11/2022] Open
Abstract
Bites by elapid snakes (e.g. cobras) can result in life-threatening paralysis caused by venom neurotoxins blocking neuromuscular nicotinic acetylcholine receptors. Here, we determine the cryo-EM structure of the muscle-type Torpedo receptor in complex with ScNtx, a recombinant short-chain α-neurotoxin. ScNtx is pinched between loop C on the principal subunit and a unique hairpin in loop F on the complementary subunit, thereby blocking access to the neurotransmitter binding site. ScNtx adopts a binding mode that is tilted toward the complementary subunit, forming a wider network of interactions than those seen in the long-chain α-Bungarotoxin complex. Certain mutations in ScNtx at the toxin-receptor interface eliminate inhibition of neuronal α7 nAChRs, but not of human muscle-type receptors. These observations explain why ScNtx binds more tightly to muscle-type receptors than neuronal receptors. Together, these data offer a framework for understanding subtype-specific actions of short-chain α-neurotoxins and inspire strategies for design of new snake antivenoms. Bites by elapid snakes can result in life-threatening paralysis caused by α-neurotoxins blocking the neuromuscular nicotinic acetylcholine receptor. Here, the authors determine the cryo-EM structure of this receptor in complex with a short-chain α-neurotoxin.
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Affiliation(s)
- Mieke Nys
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, 3000, Leuven, Belgium.
| | - Eleftherios Zarkadas
- University Grenoble Alpes, CNRS, CEA, IBS, F-38000, Grenoble, France.,University Grenoble Alpes, CNRS, CEA, EMBL, ISBG, F-38000, Grenoble, France
| | - Marijke Brams
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, 3000, Leuven, Belgium
| | - Aujan Mehregan
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, 3000, Leuven, Belgium
| | | | - Jeroen Kool
- AIMMS Division of BioMolecular Analysis, Vrije Universiteit Amsterdam, 1081, HV, Amsterdam, Netherlands
| | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK
| | | | - John E Baenziger
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Hugues Nury
- University Grenoble Alpes, CNRS, CEA, IBS, F-38000, Grenoble, France
| | - Chris Ulens
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, 3000, Leuven, Belgium.
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Mehregan A, Nys M, Brams M, Kambara K, Bertrand D, Ulens C. Characterizing the interaction of the consensus short-chain neurotoxin, ScNtx, with nicotinic acetylcholine receptors. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.1786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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Mehregan A, Ulens C. Spicy Science: Structural snapshots of a polymodal nociceptor reveal insights on our sensation to pain, heat, and taste. Cell Calcium 2022; 102:102541. [DOI: 10.1016/j.ceca.2022.102541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/02/2022]
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Sridhar A, Lummis SCR, Pasini D, Mehregan A, Brams M, Kambara K, Bertrand D, Lindahl E, Howard RJ, Ulens C. Regulation of a pentameric ligand-gated ion channel by a semiconserved cationic lipid-binding site. J Biol Chem 2021; 297:100899. [PMID: 34157288 PMCID: PMC8327344 DOI: 10.1016/j.jbc.2021.100899] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 06/10/2021] [Accepted: 06/18/2021] [Indexed: 02/08/2023] Open
Abstract
Pentameric ligand-gated ion channels (pLGICs) are crucial mediators of electrochemical signal transduction in various organisms from bacteria to humans. Lipids play an important role in regulating pLGIC function, yet the structural bases for specific pLGIC-lipid interactions remain poorly understood. The bacterial channel ELIC recapitulates several properties of eukaryotic pLGICs, including activation by the neurotransmitter GABA and binding and modulation by lipids, offering a simplified model system for structure-function relationship studies. In this study, functional effects of noncanonical amino acid substitution of a potential lipid-interacting residue (W206) at the top of the M1-helix, combined with detergent interactions observed in recent X-ray structures, are consistent with this region being the location of a lipid-binding site on the outward face of the ELIC transmembrane domain. Coarse-grained and atomistic molecular dynamics simulations revealed preferential binding of lipids containing a positive charge, particularly involving interactions with residue W206, consistent with cation-π binding. Polar contacts from other regions of the protein, particularly M3 residue Q264, further support lipid binding via headgroup ester linkages. Aromatic residues were identified at analogous sites in a handful of eukaryotic family members, including the human GABAA receptor ε subunit, suggesting conservation of relevant interactions in other evolutionary branches. Further mutagenesis experiments indicated that mutations at this site in ε-containing GABAA receptors can change the apparent affinity of the agonist response to GABA, suggesting a potential role of this site in channel gating. In conclusion, this work details type-specific lipid interactions, which adds to our growing understanding of how lipids modulate pLGICs.
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Affiliation(s)
- Akshay Sridhar
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
| | - Sarah C R Lummis
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Diletta Pasini
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Aujan Mehregan
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Marijke Brams
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | | | | | - Erik Lindahl
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden; Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Rebecca J Howard
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna, Sweden.
| | - Chris Ulens
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, Leuven, Belgium.
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Mehregan A, Ardestani G, Akizawa H, Carvacho I, Fissore R. Deletion of TRPV3 and CaV3.2 T-type channels in mice undermines fertility and Ca2+ homeostasis in oocytes and eggs. J Cell Sci 2021; 134:jcs257956. [PMID: 34313315 PMCID: PMC8313860 DOI: 10.1242/jcs.257956] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 05/17/2021] [Indexed: 12/19/2022] Open
Abstract
Ca2+ influx during oocyte maturation and after sperm entry is necessary to fill the internal Ca2+ stores and for complete egg activation. We knocked out the transient receptor potential vanilloid member 3 (TRPV3) and the T-type channel, CaV3.2, to determine their necessity for maintaining these functions in mammalian oocytes/eggs. Double-knockout (dKO) females were subfertile, their oocytes and eggs showed reduced internal Ca2+ stores, and, following sperm entry or Plcz (also known as Plcz1) cRNA injection, fewer dKO eggs displayed Ca2+ responses compared to wild-type eggs, which were also of lower frequency. These parameters were rescued and/or enhanced by removing extracellular Mg2+, suggesting that the residual Ca2+ influx could be mediated by the TRPM7 channel, consistent with the termination of divalent-cation oscillations in dKO eggs by a TRPM7 inhibitor. In total, we demonstrated that TRPV3 and CaV3.2 mediate the complete filling of the Ca2+ stores in mouse oocytes and eggs. We also showed that they are required for initiating and maintaining regularly spaced-out oscillations, suggesting that Ca2+ influx through PM ion channels dictates the periodicity and persistence of Ca2+ oscillations during mammalian fertilization.
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Affiliation(s)
- Aujan Mehregan
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, 661 North Pleasant Street, Amherst, MA 01003, USA
| | - Goli Ardestani
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, 661 North Pleasant Street, Amherst, MA 01003, USA
| | - Hiroki Akizawa
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, 661 North Pleasant Street, Amherst, MA 01003, USA
| | - Ingrid Carvacho
- Department of Biology and Chemistry, Faculty of Basic Sciences, Universidad Católica del Maule, 3480112 Talca, Chile
| | - Rafael Fissore
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, 661 North Pleasant Street, Amherst, MA 01003, USA
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Ardestani G, Mehregan A, Fleig A, Horgen FD, Carvacho I, Fissore RA. Divalent cation influx and calcium homeostasis in germinal vesicle mouse oocytes. Cell Calcium 2020; 87:102181. [PMID: 32097818 DOI: 10.1016/j.ceca.2020.102181] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 02/11/2020] [Accepted: 02/11/2020] [Indexed: 11/30/2022]
Abstract
Prior to maturation, mouse oocytes are arrested at the germinal vesicle (GV) stage during which they experience constitutive calcium (Ca2+) influx and spontaneous Ca2+ oscillations. The oscillations cease during maturation but Ca2+ influx continues, as the oocytes' internal stores attain maximal content at the culmination of maturation, the metaphase II stage. The identity of the channel(s) that underlie this Ca2+ influx has not been completely determined. GV and matured oocytes are known to express three Ca2+ channels, CaV3.2, TRPV3 and TRPM7, but females null for each of these channels are fertile and their oocytes display minor modifications in Ca2+ homeostasis, suggesting a complex regulation of Ca2+ influx. To define the contribution of these channels at the GV stage, we used different divalent cations, pharmacological inhibitors and genetic models. We found that the three channels are active at this stage. CaV3.2 and TRPM7 channels contributed the majority of Ca2+ influx, as inhibitors and oocytes from homologous knockout (KO) lines showed severely reduced Ca2+ entry. Sr2+ influx was promoted by CaV3.2 channels, as Sr2+ oscillations were negligible in CaV3.2-KO oocytes but robust in control and Trpv3-KO GV oocytes. Mn2+ entry relied on expression of CaV3.2 and TRPM7 channels, but Ni2+ entry depended on the latter. CaV3.2 and TRPV3 channels combined to fill the Ca2+ stores, although CaV3.2 was the most impactful. Studies with pharmacological inhibitors effectively blocked the influx of divalent cations, but displayed off-target effects, and occasionally agonist-like properties. In conclusion, GV oocytes express channels mediating Ca2+ and other divalent cation influx that are pivotal for fertilization and early development. These channels may serve as targets for intervention to improve the success of assisted reproductive technologies.
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Affiliation(s)
- Goli Ardestani
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, 661 North Pleasant Street, Amherst, MA, 01003, USA
| | - Aujan Mehregan
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, 661 North Pleasant Street, Amherst, MA, 01003, USA
| | - Andrea Fleig
- Center for Biomedical Research at The Queen's Medical Center and University of Hawaii Cancer Center and John A. Burns School of Medicine at the University of Hawaii, Honolulu, HI, 96813, USA
| | - F David Horgen
- Department of Natural Sciences, Hawaii Pacific University, Kaneohe, HI, 96744, USA
| | - Ingrid Carvacho
- Department of Biology and Chemistry, Faculty of Basic Sciences, Universidad Católica del Maule, 3480112, Talca, Chile
| | - Rafael A Fissore
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, 661 North Pleasant Street, Amherst, MA, 01003, USA.
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Ulens C, Bisseling Q, Brams M, Mehregan A, Evans GL, Pasini D, Beard H, Verhelst S, Fish A, van Dorst S, Kambara K, Bertrand D. Molecular Recognition of Neonicotinoid Insecticides by Honeybee Nicotinic Receptors and ACHBP Homologues. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.3171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Abstract
Changes in the intracellular concentration of calcium ([Ca2+]i) represent a vital signaling mechanism enabling communication between and among cells as well as with the environment. Cells have developed a sophisticated set of molecules, "the Ca2+ toolkit," to adapt [Ca2+]i changes to specific cellular functions. Mammalian oocytes and eggs, the subject of this review, are not an exception, and in fact the initiation of embryo devolvement in all species is entirely dependent on distinct [Ca2+]i responses. Here, we review the components of the Ca2+ toolkit present in mammalian oocytes and eggs, the regulatory mechanisms that allow these cells to accumulate Ca2+ in the endoplasmic reticulum, release it, and maintain basal and stable cytoplasmic concentrations. We also discuss electrophysiological and genetic studies that have uncovered Ca2+ influx channels in oocytes and eggs, and we analyze evidence supporting the role of a sperm-specific phospholipase C isoform as the trigger of Ca2+ oscillations during mammalian fertilization including its implication in fertility.
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Affiliation(s)
- Takuya Wakai
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Aujan Mehregan
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Rafael A Fissore
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, Massachusetts 01003
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Ulens C, Bisseling Q, Brams M, Mehregan A, Evans G, Pasini D, Gruss F. The Molecular Recognition Of The Insecticide Sulfoxaflor By Nicotinic Receptors Is Based On Atomic Interactions Identical To Bee‐Harming Neonicotinoids. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.813.6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Otite F, Mink S, Tan CO, Puri A, Zamani AA, Mehregan A, Chou S, Orzell S, Purkayastha S, Du R, Sorond FA. Impaired cerebral autoregulation is associated with vasospasm and delayed cerebral ischemia in subarachnoid hemorrhage. Stroke 2014; 45:677-82. [PMID: 24425120 DOI: 10.1161/strokeaha.113.002630] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Cerebral autoregulation may be impaired in the early days after subarachnoid hemorrhage (SAH). The purpose of this study was to examine the relationship between cerebral autoregulation and angiographic vasospasm (aVSP) and radiographic delayed cerebral ischemia (DCI) in patients with SAH. METHODS Sixty-eight patients (54±13 years) with a diagnosis of nontraumatic SAH were studied. Dynamic cerebral autoregulation was assessed using transfer function analysis (phase and gain) of the spontaneous blood pressure and blood flow velocity oscillations on days 2 to 4 post-SAH. aVSP was diagnosed using a 4-vessel conventional angiogram. DCI was diagnosed from CT. Decision tree models were used to identify optimal cut-off points for clinical and physiological predictors of aVSP and DCI. Multivariate logistic regression models were used to develop and validate a risk scoring tool for each outcome. RESULTS Sixty-two percent of patients developed aVSP, and 19% developed DCI. Patients with aVSP had higher transfer function gain (1.06±0.33 versus 0.89±0.30; P=0.04) and patients with DCI had lower transfer function phase (17.5±39.6 versus 38.3±18.2; P=0.03) compared with those who did not develop either. Multivariable scoring tools using transfer function gain>0.98 and phase<12.5 were strongly predictive of aVSP (92% positive predictive value; 77% negative predictive value; area under the receiver operating characteristic curve, 0.92) and DCI (80% positive predictive value; 91% negative predictive value; area under the curve, 0.94), respectively. CONCLUSIONS Dynamic cerebral autoregulation is impaired in the early days after SAH. Including autoregulation as part of the initial clinical and radiographic assessment may enhance our ability to identify patients at a high risk for developing secondary complications after SAH.
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Affiliation(s)
- Fadar Otite
- From the Department of Neurology, Stroke Division (F.O., S.M., A.M., S.C., S.O., F.A.S.), Department of Radiology (A.A.Z.), and Department of Neurosurgery (R.D.), Brigham and Women's Hospital, Boston, MA; Cardiovascular Research Laboratory and Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Boston, MA (C.O.T.); Institute for Aging Research, Hebrew SeniorLife, Roslindale, MA (S.P.); Harvard Medical School, Boston, MA (F.O., C.O.T., A.A.Z., A.M., S.C., S.O., S.P., R.D., F.A.S.); Department of Neurology, Klinikum Worms, Teaching Hospital of Mainz, Germany (S.M.); and Division of Neuroimaging and Neurointervention, Department of Radiology, University of Massachusetts Medical Center, Worcester, MA (A.P.)
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Purkayastha S, Fadar O, Mehregan A, Lipsitz LA, Sorond FA. Association between Cerebral tissue Structural Integrity and Dynamic Cerebral Autoregulation in Elderly Individuals. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1203.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sushmita Purkayastha
- Institute For Aging Research, Hebrew SeniorLifeBostonMA
- Harvard Medical SchoolBostonMA
| | - Otite Fadar
- Department of NeurologyBrigham and Women's HospitalBostonMA
| | - Aujan Mehregan
- Department of NeurologyBrigham and Women's HospitalBostonMA
| | - Lewis A Lipsitz
- Institute For Aging Research, Hebrew SeniorLifeBostonMA
- Harvard Medical SchoolBostonMA
| | - Farzaneh A Sorond
- Harvard Medical SchoolBostonMA
- Department of NeurologyBrigham and Women's HospitalBostonMA
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Abstract
Suppressor oncogene p53 is expressed more frequently in the nodular portion than the superficial spreading portion of the same melanoma. PCNA expression follows the same pattern but it is strongly expressed already in the superficial spreading portion. CD34 is found to label dermatofibrosarcoma protuberans. There is the mixture of negative strands but the immunostains are predominantly positive in the three cases studied. Neurogenic tumors are reactive but the intensity of staining is only moderate. Fibrous histiocytoma, dermatofibroma and other fibrohistiocytic tumors are non-reactive. CD34 is expressed in the outer root sheath of hair follicle below the sebaceous gland level. A case of piloepidermal cyst is CD34 positive. CD34 is expressed in vascular endothelial cells; not only hemangiomas but also lymphangiosarcoma is CD34 positive. A case of indeterminate cell histiocytosis following scabies and superficial variant of clear cell sarcoma are discussed as examples of new entities.
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Affiliation(s)
- K Hashimoto
- Department of Dermatology & Syphilology, Wayne State University School of Medicine, Detroit, MI 48201
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Fukaya T, Hashimoto K, Eto H, Mehregan A. Mouse monoclonal antibody (FKH1) detecting human melanoma-associated antigens. Cancer Res 1986; 46:5195-200. [PMID: 3756874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A mouse monoclonal antibody, FKH1, was produced to detect cytoplasmic melanoma-associated antigen. FKH1 was raised using cultured human melanoma cell line KHm-6 as an immunogen. Reactivity of this antibody was assessed by immunohistochemical techniques against cell lines and normal and neoplastic tissues. Positive reactions were seen against 5 human melanoma cell lines. It stained cytoplasm of melanoma cells in a diffuse and granular pattern in indirect immunofluorescence. Immunoelectron microscopy showed diffuse distribution of immunoreactant in the cytoplasm of KHm-1 cells excluding melanosomes and other organelles. Reactivity against frozen and alcohol-fixed, paraffin-embedded melanocytic tumors was also tested with IIF or indirect or avidin biotinylated horseradish peroxidase complex immunoperoxidase techniques. All cases of frozen sections from benign and malignant melanocytic tumors showed positive staining with FKH1. In fixed tissues, however, reactivity was 11 of 14 (79%) in malignant melanoma and 28 of 42 (67%) in other melanocytic tumors. FKH1 did not react against normal melanocytes and nonmelanocytic tumors except APUDoma and 2 glioblastoma cell lines. It failed to stain the B-16 mouse melanoma cell line, neuroblastoma cell line, breast carcinoma cell line, and T-cell lymphoma cell line. Normal human peripheral nerves were nonreactive with FKH1. In immunoelectroblot study, FKH1 bound with proteins having molecular weight of 71,000 and 55,000 extracted from KHm-6 cells. It was suggested that FKH1 is a useful monoclonal antibody in diagnostic study of human malignant melanoma specimens.
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Abstract
Pigmented follicular cysts are newly described cutaneous cysts with characteristic histology. They are usually single pigmented lesions occurring in men between 20 and 63 years of age that often are mistaken for nevi. The eighth case of this newly described cyst is presented; a brief review of epithelial cysts and how they differ from pigmented follicular cysts also is reported.
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Mehregan A, Plotnick H. Pigmented keratoacanthoma. Arch Dermatol 1984; 120:1417. [PMID: 6497405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Abstract
Most patients previously reported to have papular mucinosis had the generalized lichenoid papular form (scleromyxedema) with abnormal gamma globulin. Microscopic examination of affected skin showed increased acid mucopolysaccharides in the dermis and proliferation of fibroblasts. Our patient had the discrete form of papular mucinosis without abnormal serum gamma globulin but with increased amounts of acid mucopolysaccharides in the dermis and no proliferation of fibroblasts.
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Abstract
Trichoadenoma of Nikolowski is a rare benign tumor of the skin with hair follicle-like direction of differentiation. This tumor is less mature than trichofolliculoma and more differentiated than trichoepithelioma. Probably because of its rarity it has not been a well recognized tumor. We are reporting on eight cases of trichoadenoma to further define this benign growth.
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Coskey RJ, Mehregan A. Bowen disease associated with porokeratosis of Mibelli. Arch Dermatol 1975; 111:1480-1. [PMID: 1200657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A 73-year-old woman developed Bowen precancerous dermatosis in an area of porokeratosis of Mibelli on her leg. This is the fourth reported case of Bowen disease arising from porokeratosis of Mibelli. The recent literature indicates that porokeratosis of Mibelli may be due to an abnormal clone of cells, predisposing affected individuals to development of malignant neoplasms over the involved areas.
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Jackson CE, Callies QC, Krull EA, Mehregan A. Hairy cutaneous malformations of palms and soles. A hereditary condition. Arch Dermatol 1975; 111:1146-9. [PMID: 810092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Hairy cutaneous malformations of the palms and soles were observed in four generations of a French-Canadian family. The lesions were asymptomatic, bilaterally symmetrical, and involved small areas of skin of the central proximal part of the palms near the wrist and the medial aspect of the longitudinal arch of the foot. The appearance suggested a difference in quality of the skin rather than simply the presence of hair follicles. Examination of a biopsy specimen showed skin containing hair follicles. The pattern of inheritance was autosomal dominant with definate male-to-male transmission. Genetic linkage studies were generally noninformative, but evidence was obtained against close chromosomal linkage of this trait to the histocompatibility antigen (HL-A) or Rh blood group locus. The only other known case of a familiar condition was reported by Schnitzler in 1973.
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Coskey RJ, Mehregan A. Spindle cell nevi in adults and children. Plast Reconstr Surg 1974. [DOI: 10.1097/00006534-197405000-00079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Coskey RJ, Mehregan A. Spindle cell nevi in adults and children. Arch Dermatol 1973; 108:535-6. [PMID: 4745287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Coskey RJ, Mehregan A, Fosnaugh R. Bowen's disease of the nail bed. Arch Dermatol 1972; 106:79-80. [PMID: 5039111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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