The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Marion Ehrich - One of the best experts on this subject based on the ideXlab platform.
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studies exploring the interaction of the Organophosphorus Compound paraoxon with fullerenes
ACS omega, 2019Co-Authors: Philippe Bissel, Geraldine Magnin, Roberto Mcalister Counciltroche, Zhiguo Zhou, Marion EhrichAbstract:: In vitro experiments previously published demonstrated the ability of fullerenes to decrease the capability of Organophosphorus (OP) Compounds to inhibit acetylcholinesterase. Experiments described herein demonstrate molecular level affinity interactions between fullerenes and the OP test Compound paraoxon with NMR spectroscopy. The calculated binding constant of 19 M-1 indicates that this binding was not covalent.
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Organophosphorus Compound effects on neurotrophin receptors and intracellular signaling
Toxicology in Vitro, 2012Co-Authors: Melinda Pomeroyblack, Marion EhrichAbstract:Abstract Neurite outgrowth of SH-SY5Y neuroblastoma cells following the addition of spinal cord extracts from chickens exposed to a neuropathic Organophosphorus (OP) Compound suggests the presence of a growth factor during OP neuropathy. However, exposure of SH-SY5Y cells directly to neuropathic OP Compounds results in apoptosis and/or decreased neurite outgrowth. These cellular effects may follow OP-induced interference with neurotrophin-receptor binding and/or intracellular signaling resulting from receptor binding. We hypothesized that sub-lethal concentrations of a neuropathic OP Compound interferes with neurotrophin-receptor binding as well as specific intracellular signaling pathways in neuroblastoma cells which would not occur with a non-neuropathic OP Compound. SH-SY5Y cells were exposed to a neuropathic OP Compound (PSP; 0.01, 0.1, 1.0 μM), a neuropathic OP Compound with nerve growth factor (1.0 μM PSP + 1 ng/ml NGF), a non-neuropathic OP Compound (paraoxon; 100 μM), and medium only for 4, 8, 24, and 48 h. Western blots indicate that cells exposed to a low dose of PSP or the high dose of PSP + NGF contained the phosphorylated form of a common neurotrophin receptor (pp75) that was four times greater than that of the phosphorylated form of the high-affinity NGF receptor (pTrkA) suggesting that p75 activation may contribute to early cell death after exposure to OP Compounds. Furthermore, events in signaling pathways after exposure to PSP differed from those after exposure to paraoxon, with activation of the MEK1/2 protein increasing significantly only after exposure to paraoxon. Both types of OP Compounds, however, caused significant activation of Akt in the PI-3K cell-survival pathway. These results suggest that exposure to a non-neuropathic OP Compound causes increased activity of the MAPK pathway whereas exposure to neuropathic OP Compounds prevented upregulation of the pathway. Since this pathway is integral to neurite outgrowth and cell survival, this study has revealed molecular mechanisms implicated in neuronal response after exposure to neuropathic OP Compounds.
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Organophosphorus Compound induced delayed neurotoxicity in white leghorn hens assessed by fluoro jade
International Journal of Toxicology, 2004Co-Authors: Kent Carlson, Marion EhrichAbstract:Certain Organophosphorus (OP) Compounds can induce a delayed neuropathy, termed OPIDN, that involves central and peripheral nervous system axons, terminals, and perikarya. Historically, OPIDN has been characterized by staining neural sections with silver or hematoxylin and eosin (H&E). This study utilized a novel staining method, Fluoro-Jade, for evaluating the distribution and extent of OPIDN in the central nervous system of hens. Results were then compared to synoptically sectioned and stained H&E preparations. White Leghorn hens were injected with phenyl saligenin phosphate (PSP, 2.5 mg/kg, intramuscular [im]), triphenyl phosphite (TPPi, 500 mg/kg, subcutaneous [sc]), or dimethyl sulfoxide vehicle (DMSO, 0.5 ml/kg, im or sc) and evaluated clinically for signs of neurological dysfunction associated with OPIDN. Hens were sacrificed 7, 14, and 21 days post dosing. Brains and spinal cords were removed immediately following sacrifice, fixed in formalin, and embedded in paraffin. Microtomecut sections (7 μm)...
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Organophosphorus Compound induced apoptosis in sh sy5y human neuroblastoma cells
Toxicology and Applied Pharmacology, 2000Co-Authors: Kent Carlson, Bernard S Jortner, Marion EhrichAbstract:Organophosphorus (OP) Compounds have been shown to be cytotoxic to SH-SY5Y human neuroblastoma cell cultures. The mechanisms involved in OP Compound-induced cell death (apoptosis versus necrosis) were assessed morphologically by looking at nuclear fragmentation and budding using the fluorescent stain Hoechst 33342 (10 μg/ml). Hoechst staining revealed significant paraoxon (1 mM), parathion (1 mM), phenyl saligenin phosphate (PSP, 10 and 100 μM), tri-ortho-tolyl phosphate (TOTP, 100 μM and 1 mM), and triphenyl phosphite (TPPi, 1 mM) induced time-dependent increases in traditional apoptosis (p < 0.05). In many cells, PSP and TOTP (1 mM) also induced nuclear condensation with little fragmentation or budding. Pretreatment with cyclosporin A (500 nM, 30 h) decreased apoptosis following 1 mM parathion and TOTP exposures. Apoptotic nuclear changes were verified by DNA gel electrophoresis. Activation of caspase-3, a cysteine aspartate protease, was also monitored. OP Compounds induced significant time-dependent increases in caspase-3 activation following paraoxon (1 mM), parathion (100 μM, 1 mM), PSP (10 μM, 100 μM, 1 mM), TOTP (100 μM, 1 mM), and TPPi (1 mM) exposure (p < 0.05). Pretreatment with cyclosporin A (500 nM, 30 h) significantly decreased caspase-3 activation during extended incubations with paraoxon, parathion, and TPPi (p < 0.05). In addition, pretreatment with the caspase-3 inhibitor Ac-DEVD-CHO and the caspase-8 inhibitor Ac-IETD-CHO (25 μM, 8 h) significantly decreased caspase-3 activation following exposure to 1 mM PSP and parathion (p < 0.05). Pretreatment with the serine protease inhibitor phenylmethyl sulfonyl fluoride (PMSF; 1 mM, 8 h) also significantly decreased caspase activation following 1 mM PSP and TOTP exposures (p < 0.05). Alteration of OP Compound-induced nuclear fragmentation or caspase-3 activation by pretreatment with cyclosporin A, Ac-IETD-CHO, or PMSF suggested that OP Compound-induced cytotoxicity may be modulated through multiple sites, including mitochondrial permeability pores, receptor-mediated caspase pathways, or serine proteases.
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Organophosphorus Compound induced modification of sh sy5y human neuroblastoma mitochondrial transmembrane potential
Toxicology and Applied Pharmacology, 1999Co-Authors: Kent Carlson, Marion EhrichAbstract:Abstract Organophosphorus (OP) Compounds inhibit mitochondrial enzymes, respiration, and ATP generation, in addition to inducing structural changes such as matrix swelling. This implicates mitochondria as primary subcellular targets for these Compounds. In this study, the health and function of cellular mitochondria following OP Compound exposure were assessed by evaluating the mitochondrial transmembrane potential (ΔΨm). This was done by measuring the changes in ΔΨm in SH-SY5Y human neuroblastoma cells incubated with the cationic fluorochrome, rhodamine 123 (5 μg/ml), and the OP Compounds tri-ortho-tolyl phosphate (TOTP), triphenyl phosphite (TPPi), or parathion for 7.5 to 960 minutes. OP Compounds (100 μM to 1 mM) induced significant concentration-dependent mitochondrial hyperpolarization with peak maxima occurring at 60 (TOTP, TPPi) or 120 (parathion) min. Following this, the mitochondrial membranes gradually depolarized. Pretreatment with cyclosporin A (500 nM, 30 h), a mitochondrial permeability transition pore (PTP) inhibitor, decreased the hyperpolarization. In contrast, 30-h pretreatment with the muscarinic receptor agonist carbachol (1 mM) significantly increased ΔΨm and delayed subsequent depolarization. Hyperpolarization and subsequent depolarization of mitochondrial membranes occurred 16 to 24 h prior to a loss of substrate adhesion or an increase in DNA fragmentation, indicating that mitochondria were a primary target in OP Compound-initiated cytotoxicity.
Shinichiro Suye - One of the best experts on this subject based on the ideXlab platform.
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green fluorescent protein doped sol gel silica planar waveguide to detect Organophosphorus Compound
Third Asia Pacific Optical Sensors Conference, 2012Co-Authors: Yasufumi Enami, Shinichiro SuyeAbstract:We report novel living protein-doped planar waveguide, and real-time detection of an Organophosphorus Compound using a sol-gel silica planar waveguide doped with a green fluorescent protein and an Organophosphorus hydrolase on a yeast-cell surface. The waveguide was pumped at 488 nm, and emitted green fluorescence at the far field. The green fluorescent light at 550 nm changed by 50% from the original power 1 min after application of the Organophosphorus Compound. The results enable the real-time detection of biochemical weapon and insecticide harmful for human body by using an in-line fiber sensor network.
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detection of Organophosphorus Compound based on a sol gel silica planar waveguide doped with a green fluorescent protein and an Organophosphorus hydrolase
Applied Physics Letters, 2011Co-Authors: Yasufumi Enami, Keiji Tsuchiya, Shinichiro SuyeAbstract:In this letter, the authors report the real-time detection of an Organophosphorus Compound using a sol–gel silica planar waveguide doped with a green fluorescent protein and an Organophosphorus hydrolase on a yeast-cell surface display. The waveguide was pumped at 488 nm, and it emitted green fluorescence at the far field. The green fluorescent light at 550 nm changed by 50% from the original power 1 min after application of the Organophosphorus Compound. The results enable the real-time detection of sarin and other biochemicals by using an in-line fiber sensor network.
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Organophosphorus Compound detection on a cell chip with yeast coexpressing hydrolase and egfp
Biotechnology Journal, 2010Co-Authors: Takeshi Fukuda, Keiji Tsuchiya, Hirokazu Makishima, Kouta Tsuchiyama, Ashok Mulchandani, Kouichi Kuroda, Mitsuyoshi Ueda, Shinichiro SuyeAbstract:: Organophosphorus Compounds (OPs) such as pesticides, fungicides, and herbicides are highly toxic but are nevertheless extensively used worldwide. To detect OPs, we constructed a yeast strain that co-displays Organophosphorus hydrolase (OPH) and enhanced green fluorescent protein (EGFP) on the cell surface using a Flo1p anchor system. OP degradation releases protons and causes a change in pH. This pH change results in structural deformation of EGFP, which triggers quenching of its fluorescence, thereby making this cell useful for visual detection of OPs. Fluorescence microscopy confirmed the high-intensity fluorescence displayed by EGFP on the cell surface. The yeast strain possessed sufficient OPH hydrolytic activities for degrading OPs, as measured by incubation with 1 mM paraoxon for 24 h at 30 degrees C. In addition, with 20 mM paraoxon at 30 degrees C, fluorescence quenching of EGFP on the single yeast cell was observed within 40 s in a microchamber chip. These observations suggest that engineered yeast cells are suitable for simultaneous degradation and visual detection of OPs.
Kent Carlson - One of the best experts on this subject based on the ideXlab platform.
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Organophosphorus Compound induced delayed neurotoxicity in white leghorn hens assessed by fluoro jade
International Journal of Toxicology, 2004Co-Authors: Kent Carlson, Marion EhrichAbstract:Certain Organophosphorus (OP) Compounds can induce a delayed neuropathy, termed OPIDN, that involves central and peripheral nervous system axons, terminals, and perikarya. Historically, OPIDN has been characterized by staining neural sections with silver or hematoxylin and eosin (H&E). This study utilized a novel staining method, Fluoro-Jade, for evaluating the distribution and extent of OPIDN in the central nervous system of hens. Results were then compared to synoptically sectioned and stained H&E preparations. White Leghorn hens were injected with phenyl saligenin phosphate (PSP, 2.5 mg/kg, intramuscular [im]), triphenyl phosphite (TPPi, 500 mg/kg, subcutaneous [sc]), or dimethyl sulfoxide vehicle (DMSO, 0.5 ml/kg, im or sc) and evaluated clinically for signs of neurological dysfunction associated with OPIDN. Hens were sacrificed 7, 14, and 21 days post dosing. Brains and spinal cords were removed immediately following sacrifice, fixed in formalin, and embedded in paraffin. Microtomecut sections (7 μm)...
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Organophosphorus Compound induced apoptosis in sh sy5y human neuroblastoma cells
Toxicology and Applied Pharmacology, 2000Co-Authors: Kent Carlson, Bernard S Jortner, Marion EhrichAbstract:Organophosphorus (OP) Compounds have been shown to be cytotoxic to SH-SY5Y human neuroblastoma cell cultures. The mechanisms involved in OP Compound-induced cell death (apoptosis versus necrosis) were assessed morphologically by looking at nuclear fragmentation and budding using the fluorescent stain Hoechst 33342 (10 μg/ml). Hoechst staining revealed significant paraoxon (1 mM), parathion (1 mM), phenyl saligenin phosphate (PSP, 10 and 100 μM), tri-ortho-tolyl phosphate (TOTP, 100 μM and 1 mM), and triphenyl phosphite (TPPi, 1 mM) induced time-dependent increases in traditional apoptosis (p < 0.05). In many cells, PSP and TOTP (1 mM) also induced nuclear condensation with little fragmentation or budding. Pretreatment with cyclosporin A (500 nM, 30 h) decreased apoptosis following 1 mM parathion and TOTP exposures. Apoptotic nuclear changes were verified by DNA gel electrophoresis. Activation of caspase-3, a cysteine aspartate protease, was also monitored. OP Compounds induced significant time-dependent increases in caspase-3 activation following paraoxon (1 mM), parathion (100 μM, 1 mM), PSP (10 μM, 100 μM, 1 mM), TOTP (100 μM, 1 mM), and TPPi (1 mM) exposure (p < 0.05). Pretreatment with cyclosporin A (500 nM, 30 h) significantly decreased caspase-3 activation during extended incubations with paraoxon, parathion, and TPPi (p < 0.05). In addition, pretreatment with the caspase-3 inhibitor Ac-DEVD-CHO and the caspase-8 inhibitor Ac-IETD-CHO (25 μM, 8 h) significantly decreased caspase-3 activation following exposure to 1 mM PSP and parathion (p < 0.05). Pretreatment with the serine protease inhibitor phenylmethyl sulfonyl fluoride (PMSF; 1 mM, 8 h) also significantly decreased caspase activation following 1 mM PSP and TOTP exposures (p < 0.05). Alteration of OP Compound-induced nuclear fragmentation or caspase-3 activation by pretreatment with cyclosporin A, Ac-IETD-CHO, or PMSF suggested that OP Compound-induced cytotoxicity may be modulated through multiple sites, including mitochondrial permeability pores, receptor-mediated caspase pathways, or serine proteases.
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Organophosphorus Compound induced modification of sh sy5y human neuroblastoma mitochondrial transmembrane potential
Toxicology and Applied Pharmacology, 1999Co-Authors: Kent Carlson, Marion EhrichAbstract:Abstract Organophosphorus (OP) Compounds inhibit mitochondrial enzymes, respiration, and ATP generation, in addition to inducing structural changes such as matrix swelling. This implicates mitochondria as primary subcellular targets for these Compounds. In this study, the health and function of cellular mitochondria following OP Compound exposure were assessed by evaluating the mitochondrial transmembrane potential (ΔΨm). This was done by measuring the changes in ΔΨm in SH-SY5Y human neuroblastoma cells incubated with the cationic fluorochrome, rhodamine 123 (5 μg/ml), and the OP Compounds tri-ortho-tolyl phosphate (TOTP), triphenyl phosphite (TPPi), or parathion for 7.5 to 960 minutes. OP Compounds (100 μM to 1 mM) induced significant concentration-dependent mitochondrial hyperpolarization with peak maxima occurring at 60 (TOTP, TPPi) or 120 (parathion) min. Following this, the mitochondrial membranes gradually depolarized. Pretreatment with cyclosporin A (500 nM, 30 h), a mitochondrial permeability transition pore (PTP) inhibitor, decreased the hyperpolarization. In contrast, 30-h pretreatment with the muscarinic receptor agonist carbachol (1 mM) significantly increased ΔΨm and delayed subsequent depolarization. Hyperpolarization and subsequent depolarization of mitochondrial membranes occurred 16 to 24 h prior to a loss of substrate adhesion or an increase in DNA fragmentation, indicating that mitochondria were a primary target in OP Compound-initiated cytotoxicity.
Yasufumi Enami - One of the best experts on this subject based on the ideXlab platform.
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green fluorescent protein doped sol gel silica planar waveguide to detect Organophosphorus Compound
Third Asia Pacific Optical Sensors Conference, 2012Co-Authors: Yasufumi Enami, Shinichiro SuyeAbstract:We report novel living protein-doped planar waveguide, and real-time detection of an Organophosphorus Compound using a sol-gel silica planar waveguide doped with a green fluorescent protein and an Organophosphorus hydrolase on a yeast-cell surface. The waveguide was pumped at 488 nm, and emitted green fluorescence at the far field. The green fluorescent light at 550 nm changed by 50% from the original power 1 min after application of the Organophosphorus Compound. The results enable the real-time detection of biochemical weapon and insecticide harmful for human body by using an in-line fiber sensor network.
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detection of Organophosphorus Compound based on a sol gel silica planar waveguide doped with a green fluorescent protein and an Organophosphorus hydrolase
Applied Physics Letters, 2011Co-Authors: Yasufumi Enami, Keiji Tsuchiya, Shinichiro SuyeAbstract:In this letter, the authors report the real-time detection of an Organophosphorus Compound using a sol–gel silica planar waveguide doped with a green fluorescent protein and an Organophosphorus hydrolase on a yeast-cell surface display. The waveguide was pumped at 488 nm, and it emitted green fluorescence at the far field. The green fluorescent light at 550 nm changed by 50% from the original power 1 min after application of the Organophosphorus Compound. The results enable the real-time detection of sarin and other biochemicals by using an in-line fiber sensor network.
Robert J Higgins - One of the best experts on this subject based on the ideXlab platform.
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avian embryonic brain reaggregate culture system i characterization for Organophosphorus Compound toxicity studies
Toxicology and Applied Pharmacology, 1994Co-Authors: Kathleen A Funk, Barry W Wilson, Robert J HigginsAbstract:Abstract An avian reaggregate culture system was characterized biochemically and morphologically for use in acute and chronic Organophosphorus Compound (OP) toxicity studies. Ten-day-old chick embryo brains were dissociated, reaggregated. and maintained in a chemically defined, serum- and antibiotic-free media. Acetylcholinesterase (ACHE), neuropathy target esterase (NTE), and 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNP) were examined due to inhibition of these enzymes as a result of acute OP toxicity (ACHE) or delayed toxicity (NTE, CNP). The selected enzymes also indicate reaggregate neuronal (ACHE, possibly NTE), oligodendroglial (CNP), and astrocytic (glutamine synthetase (GS)) activities. Enzyme activities were compared to those in age-matched chick embryo and hatched chick brains. Reaggregate ACHE specific activity was similar to or higher than that of chick embryo or hatched chick. Reaggregate NTE specific activity was initially similar to that of 10-day-old chick embryo, and then increased but subsequently averaged 7.8 nmol/min/mg protein. In chick brain, NTE peaked at hatching and averaged 28 nmol/min/mg protein thereafter. Reaggregate CNP specific activity ranged from 103 to 426 nmol/min/mg protein, whereas activity gradually increased in chick embryo brain to an average of 140 nmol/min/mg protein posthatching. The mean GS activity ranged from 0.15 (Culture Day 4) to 1.09 nmol/min/mg protein (Culture Day 62). Mean protein values per flask ranged from 2.47 to 7.58 mg. Ultrastructurally, myelination was detected at Culture Day 7 and synapses at Day 6. The biochemical and ultrastructural features demonstrate that this reaggregate culture is a practical and sensitive in vitro system for studying both the acute and the long-term neurotoxicological effects of Organophosphorus Compounds.
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avian embryonic brain reaggregate culture system ii nte activity discriminates between effects of a single neuropathic or nonneuropathic Organophosphorus Compound exposure
Toxicology and Applied Pharmacology, 1994Co-Authors: Kathleen A Funk, Robert J Higgins, Barry W WilsonAbstract:Abstract Biochemical responses after a single exposure to either a neuropathic or a nonneuropathic Organophosphorus Compound (OP) were compared using chick embryonic brain cell reaggregates. Ten-day-old chick embryo brains were dissociated and then reaggregated and maintained in a chemically defined, serum-free medium without antibiotics. Seven days later, these cultures were treated for 20 min with either neuropathic diisopropyl phosphorofluoridate (DFP, 10 −4 M) or nonneuropathic paraoxon (10 −6 M). Reaggregates were assayed for acetylcholinesterase (ACHE), neuropathy target esterase (NTE), and 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNP) activities for up to 32 days after exposure. These enzymes were examined due to inhibition of activity as a result of acute OP toxicity (ACHE) or delayed toxicity (NTE, CNP). DFP inhibited >95% of NTE activity immediately after exposure. By Postexposure Day 2, NTE specific activity was 22% of untreated activity but was similar to the untreated group levels by Postexposure Day 7. Paraoxon exposure did not affect NTE activity. Both paraoxon and DFP inhibited >99% of ACHE activity immediately after exposure. By Postexposure Day 2, ACHE specific activity in paraoxon-exposed cultures had recovered while ACHE remained 56% inhibited in DFP-exposed cultures. Both paraoxon- and DFP-exposed cultures recovered ACHE activity immediately following OP exposure if treated postexposure with an oxime reactivator, 2-pralidoxime. CNP specific activity was not affected by either paraoxon or DFP. These results demonstrated distinct differences in reaggregate NTE and ACHE activities after single exposure to neuropathic DFP and nonneuropathic paraoxon similar to those in avian in vivo assays.