GAD65/67 Mean (± SD) Cell Counts of GABAergic Neurones in the Primary (BA17) and Secondary (BA18)... more GAD65/67 Mean (± SD) Cell Counts of GABAergic Neurones in the Primary (BA17) and Secondary (BA18) Visual cortex in Dementia with Lewy Bodies and Alzheimer's disease. (DOC 30 kb)
Neurodegenerative Disease Pathology in the Occipital Lobe in (A) Control and (B) Alzheimer's ... more Neurodegenerative Disease Pathology in the Occipital Lobe in (A) Control and (B) Alzheimer's disease cases. Representative staining for α-synuclein, Aβ (4G8), and hyperphosphorylated tau (AT8) in primary visual cortex (BA17), secondary visual cortex (BA18), and lateral occipital cortex (BA37) in A) elderly normal control or in B) AD individuals. An absence of α-synuclein pathology was seen in BA17 in either AD or controls cases. Similarly, an absence of AT8 (hyperphosphorylated tau) staining was seen in BA17 in controls, but increasing levels were seen in BA17, BA18 and BA37 in AD. Aβ (4G8 antibody) pathology was present in all cortical regions examined with high levels seen in BA17 in AD cases and in other cortical regions examined. Photomicrographs were taken at x2.5 magnification (upper rows) or at x40 magnification (lower rows) with scale bars at 1000 μm (upper rows) or 50 μm (lower rows). (ZIP 1315 kb)
Excel files (hippocampus and dorsal raphe nucleus) containing differential brain gene expression ... more Excel files (hippocampus and dorsal raphe nucleus) containing differential brain gene expression data and Ingenuity pathway analysis values from rats chronically exposed to diazinon. Adult male Lister Hooded rats (Charles River, UK) were orally administered the organophosphate pesticide diazinon 0, 1 or 2 mg / kg (n = 12 per dose; 1 ml/kg olive oil) for 12 weeks, 5 consecutive days per week. Animals were overdosed with isoflurane, and trunk blood was collected and brains rapidly removed, cut into 3 mm coronal slices and stored at -80°C. The hippocampus from the right hemisphere (0, 2 mg / kg diazinon, n = 12 per dose) and whole dorsal raphe nucleus (0, 2 mg / kg diazinon, n = 6 per dose) was homogenised in Tri Reagent. RNA was extracted from homogenate and shipped to AROS Applied Biotechnology (Denmark), who used Affymetrix GeneChip® HT RG-230 PM 24-Array Plate on the Gene Titan platform to conduct expression profiling. Statistical analysis was conducted by the Bioinformatics Service (Newcastle University). Raw data were exported to the Bioconductor package, RankProd, log-scale transformed (log, basis 2) and normalised (non-linear transformation employing the loess smoother). Probe sets (78,963) were detected in all samples (20% and 90% bound of the fluorescence intensity of the chip). For the detection of gene expression changes, an ANOVA was applied with a cut off at a false discovery rate p < 0.05. All up-regulated and All down-regulated worksheets = probe sets significantly detected in samples. Significant worksheet = genes significantly different between vehicle and diazinon treated animals function, pathway and network worksheets = Ingenuity pathway analysis was conducted on genes that were significantly altered to generate functions and canonical pathways using the Ingenuity Systems reference set that were most significant to the data set. The p value was determined by the probability that the association between the genes in the dataset and the function or canonical pathway is explained by chance alone [...]
The ionic liquid 1-octyl-3-methylimidazolium (M8OI) has been found in the environment and identif... more The ionic liquid 1-octyl-3-methylimidazolium (M8OI) has been found in the environment and identified as a hazard for triggering the liver disease primary biliary cholangitis (PBC). Given limited toxicity data for M8OI and other structurally-related ionic liquids, target organs for M8OI toxicity were examined. Adult male C57Bl6 mice were acutely exposed to 0-10 mg/kg body weight M8OI via 2 intraperitoneal injections (time zero and 18 h) and effects examined at 24 h. At termination, tissue histopathology, serum and urinary endpoints were examined. No overt pathological changes were observed in the heart and brain. In contrast, focal and mild to multifocal and moderate degeneration with a general trend for an increase in severity with increased dose was observed in the kidney. These changes were accompanied by a dose-dependent increased expression of Kim1 in kidney tissue, marked elevations in urinary Kim1 protein and a dose-dependent increase in serum creatinine. Hepatic changes were limited to a significant dose-dependent loss of hepatic glycogen and a mild but significant increase in portal tract inflammatory recruitment and/or fibroblastic proliferation accompanied by a focal fibrotic change. Cultured mouse tissue slices reflected these in vivo effects in that dose-dependent injury was observed in kidney slices but not in the liver. Kidney slices accumulated higher levels of M8OI than liver slices (e.g. at 10 μM, greater than 4 fold) and liver slices where markedly more active in the metabolism of M8OI. These data indicate that the kidney is a target organ for the toxic effects of M8OI accompanied by mild cholangiopathic changes in the liver after intraperitoneal administration.
ISBN 0 824 7922 X. Endotoxins are an important cause of lung damage and, too frequently, patient ... more ISBN 0 824 7922 X. Endotoxins are an important cause of lung damage and, too frequently, patient death. Consequently this book is to be welcomed, since it brings together in one volume much of the basic research into the underlying mechanisms of endotoxin action on the lung and the application of this research to clinical practice. The format of the book reflects the list of contributing authors, a mix of scientists and clinicians, and competently progresses from a discussion of basic knowledge of the toxic properties of endotoxin and its mechanisms of action on the respiratory system, through to the clinical effects and therapeutic manoeuvres for the management of the septic patient. The book ends with speculation about the potential uses of gene therapy in the treatment of such patients. Each chapter is well referenced, and, as we have now come to expect from the series, the quality of production, editorial style and illustrations are all
Mutation Research/Genetic Toxicology and Environmental Mutagenesis, 2000
Occupational exposure to organophosphorus insecticides (OPs), such as diazinon, may be monitored ... more Occupational exposure to organophosphorus insecticides (OPs), such as diazinon, may be monitored by the measurement of the activity of peripheral cholinesterase enzymes, including erythrocyte acetylcholinesterase (EAChE) and plasma or serum cholinesterase (plasma or serum ChE). Exposures have also been measured by the analysis of dialkyl phosphate metabolites of OPs in urine. The potential health risks associated with exposure, especially those of a neurological nature, may then be estimated, and appropriate measures to reduce or eliminate exposures can be implemented. There is evidence that some OP pesticides may have in vivo genotoxic effects, suggesting a possible link with cancer with long term or repeated heavy exposures. This paper describes work performed in 17 subjects with a single or two exposures to a sheep dip containing diazinon. Urine samples revealed OP metabolites dimethylphosphate (DMP), dimethylthiophosphate (DMTP), diethylphosphate (DEP) and diethylthiophosphate (DETP) in 37% of subjects at low levels which were not elevated after exposure. EAChE and plasma ChE were also unchanged before and after exposure, and were similar to those measured in unexposed control groups. Sister chromatid exchanges (SCE), a marker of chromosome damage, was significantly elevated in peripheral blood lymphocytes after exposure compared with before. SCE were unchanged in a group of non-occupationally exposed workers. In vitro studies with both authentic diazinon (98%) and diazinon in a sheep dip formulation (45%) showed increased SCE and decreased replicative indices, suggesting toxic and genotoxic effects of diazinon.
1 Sulphur mustard reacts directly with benzenethiols and cysteine esters in aqueous medium. 2 Ben... more 1 Sulphur mustard reacts directly with benzenethiols and cysteine esters in aqueous medium. 2 Benzenethiols diffuse into lung slices in short term culture. 3 Treatment of lung slices in short term culture with benzenethiols does not protect cellular glutathione from conjugation with sulphur mustard. 4 Following uptake of cysteine ester into lung slices cysteine is elevated but this does not protect cellular glutathione from sulphur mustard.
1 Multiple low doses of the direct acting organopho sphates, ecothiopate, paraoxon and mipafox pr... more 1 Multiple low doses of the direct acting organopho sphates, ecothiopate, paraoxon and mipafox produced persistent and additive inhibition of diaphragm acetylcholinesterase. Paraoxon and mipafox had similar effects on brain acetylcholinesterase. There was greater recovery from inhibition between doses for paraoxon and ecothiopate than for mipafox. 2 Ecothiopate did not inhibit brain acetylcholinesterase but there was a small increase in activity. 3 Mipafox also had a cumulative inhibitory effect on brain neuropathy target esterase. 4 These results have particular implication for the use of multiple low doses of organophosphates occupation- ally by man.
1 The in vitro metabolism ofn-hexane was studied in rat liver, lung, brain and skeletal muscle mi... more 1 The in vitro metabolism ofn-hexane was studied in rat liver, lung, brain and skeletal muscle microsomes and in microsomes prepared from cell lines expressing human cytochrome P-450 2E1 or 2B6. The hydro xylated metabolites ofn-hexane were quantified by gas chromatography-mass spectometry. 2 Rat liver and extensor digitorum longus (EDL, fast- twitch skeletal muscle) microsomes and the CYP 2B6 microsomes produced the pre-neurotoxic metabolite of n-hexane, 2-hexanol as a major metabolite in contrast to the other rat tissues examined. 3 Inhibition of 2- and 3-hexanol production from n- hexane by rat lung microsomes using metyrapone, an inhibitor of cytochrome P-450 2B1 activity, resulted in almost complete inhibition of lung microsomal activ ity. 4 Production of all three hexanols was significantly increased with phenobarbital-induced rat liver micro somes, with a 10-fold increase in 2- and 3-hexanol production. A slight increase in 2-hexanol production with phenobarbital-induced rat ...
1 Interindividual variations in an unexposed population have been defined for five enzymes involv... more 1 Interindividual variations in an unexposed population have been defined for five enzymes involved in organophosphate (OP) toxicity. The enzymes measured were: red blood cell acetylcholinesterase (AChE), lymphocyte neuropathy target esterase (NTE), serum cholinesterase (ChE), serum paraoxonase and serum arylesterase. 2 AChE and arylesterase were normally distributed in the population whilst the distribution of NTE, ChE and paraoxonase deviated significantly from normal. 3 Assay precision and intra-individual variability were measured for each of the enzymes; the effect on interindividual variation was assessed. 4 Variations in enzyme activities between individuals could have profound effects on susceptibility to OP toxicity. Prior determination of these enzymes may be predictive of susceptibility. 5 Lymphocyte NTE has some limitations as an indicator of exposure to neurotoxic OPs.
1 Male albino mice were injected s.c. with an organopho sphate (mipafox, ecothiopate or paraoxon)... more 1 Male albino mice were injected s.c. with an organopho sphate (mipafox, ecothiopate or paraoxon). Treat ments were either a single injection or multiple daily injections with lower doses for 5 or 8 days. At 3 h after injection the activity of brain and diaphragm acet ylcholinesterase and of brain neuropathy target esterase (NTE) was measured. Also measured in the diaphragm at 3 h post dose was the duration of spontaneous miniature endplate potentials (eMEPPs), recorded extracellularly. 2 At 7 and 28 days after dosing action potentials and evoked endplate potentials, produced by stimulating the phrenic nerve at 30 Hz, were recorded in diaphragm muscle. The amplitudes, time-course and latencies of these potentials were measured and the variability of latencies (jitter) was calculated. 3 Single doses of mipafox (20 mg/kg), ecothiopate (0.192 mg/kg) or paraoxon (0.415 mg/kg) in the mouse produced ca. 70% inhibition of diaphragm acetylcho linesterase at 3 h after dosing. All three OPs p...
There is a marked variability in the susceptibility of different cell types in the nervous system... more There is a marked variability in the susceptibility of different cell types in the nervous system to toxic insult. Some of this variation is associated with factors related to the specific functions of the cells, but some also reflects genetic differences in metabolism. It is important that the role of genetic polymorphisms are considered, along with the broader aspects of susceptibility to neurotoxins, in the development of certain neurological disorders.
GAD65/67 Mean (± SD) Cell Counts of GABAergic Neurones in the Primary (BA17) and Secondary (BA18)... more GAD65/67 Mean (± SD) Cell Counts of GABAergic Neurones in the Primary (BA17) and Secondary (BA18) Visual cortex in Dementia with Lewy Bodies and Alzheimer's disease. (DOC 30 kb)
Neurodegenerative Disease Pathology in the Occipital Lobe in (A) Control and (B) Alzheimer's ... more Neurodegenerative Disease Pathology in the Occipital Lobe in (A) Control and (B) Alzheimer's disease cases. Representative staining for α-synuclein, Aβ (4G8), and hyperphosphorylated tau (AT8) in primary visual cortex (BA17), secondary visual cortex (BA18), and lateral occipital cortex (BA37) in A) elderly normal control or in B) AD individuals. An absence of α-synuclein pathology was seen in BA17 in either AD or controls cases. Similarly, an absence of AT8 (hyperphosphorylated tau) staining was seen in BA17 in controls, but increasing levels were seen in BA17, BA18 and BA37 in AD. Aβ (4G8 antibody) pathology was present in all cortical regions examined with high levels seen in BA17 in AD cases and in other cortical regions examined. Photomicrographs were taken at x2.5 magnification (upper rows) or at x40 magnification (lower rows) with scale bars at 1000 μm (upper rows) or 50 μm (lower rows). (ZIP 1315 kb)
Excel files (hippocampus and dorsal raphe nucleus) containing differential brain gene expression ... more Excel files (hippocampus and dorsal raphe nucleus) containing differential brain gene expression data and Ingenuity pathway analysis values from rats chronically exposed to diazinon. Adult male Lister Hooded rats (Charles River, UK) were orally administered the organophosphate pesticide diazinon 0, 1 or 2 mg / kg (n = 12 per dose; 1 ml/kg olive oil) for 12 weeks, 5 consecutive days per week. Animals were overdosed with isoflurane, and trunk blood was collected and brains rapidly removed, cut into 3 mm coronal slices and stored at -80°C. The hippocampus from the right hemisphere (0, 2 mg / kg diazinon, n = 12 per dose) and whole dorsal raphe nucleus (0, 2 mg / kg diazinon, n = 6 per dose) was homogenised in Tri Reagent. RNA was extracted from homogenate and shipped to AROS Applied Biotechnology (Denmark), who used Affymetrix GeneChip® HT RG-230 PM 24-Array Plate on the Gene Titan platform to conduct expression profiling. Statistical analysis was conducted by the Bioinformatics Service (Newcastle University). Raw data were exported to the Bioconductor package, RankProd, log-scale transformed (log, basis 2) and normalised (non-linear transformation employing the loess smoother). Probe sets (78,963) were detected in all samples (20% and 90% bound of the fluorescence intensity of the chip). For the detection of gene expression changes, an ANOVA was applied with a cut off at a false discovery rate p < 0.05. All up-regulated and All down-regulated worksheets = probe sets significantly detected in samples. Significant worksheet = genes significantly different between vehicle and diazinon treated animals function, pathway and network worksheets = Ingenuity pathway analysis was conducted on genes that were significantly altered to generate functions and canonical pathways using the Ingenuity Systems reference set that were most significant to the data set. The p value was determined by the probability that the association between the genes in the dataset and the function or canonical pathway is explained by chance alone [...]
The ionic liquid 1-octyl-3-methylimidazolium (M8OI) has been found in the environment and identif... more The ionic liquid 1-octyl-3-methylimidazolium (M8OI) has been found in the environment and identified as a hazard for triggering the liver disease primary biliary cholangitis (PBC). Given limited toxicity data for M8OI and other structurally-related ionic liquids, target organs for M8OI toxicity were examined. Adult male C57Bl6 mice were acutely exposed to 0-10 mg/kg body weight M8OI via 2 intraperitoneal injections (time zero and 18 h) and effects examined at 24 h. At termination, tissue histopathology, serum and urinary endpoints were examined. No overt pathological changes were observed in the heart and brain. In contrast, focal and mild to multifocal and moderate degeneration with a general trend for an increase in severity with increased dose was observed in the kidney. These changes were accompanied by a dose-dependent increased expression of Kim1 in kidney tissue, marked elevations in urinary Kim1 protein and a dose-dependent increase in serum creatinine. Hepatic changes were limited to a significant dose-dependent loss of hepatic glycogen and a mild but significant increase in portal tract inflammatory recruitment and/or fibroblastic proliferation accompanied by a focal fibrotic change. Cultured mouse tissue slices reflected these in vivo effects in that dose-dependent injury was observed in kidney slices but not in the liver. Kidney slices accumulated higher levels of M8OI than liver slices (e.g. at 10 μM, greater than 4 fold) and liver slices where markedly more active in the metabolism of M8OI. These data indicate that the kidney is a target organ for the toxic effects of M8OI accompanied by mild cholangiopathic changes in the liver after intraperitoneal administration.
ISBN 0 824 7922 X. Endotoxins are an important cause of lung damage and, too frequently, patient ... more ISBN 0 824 7922 X. Endotoxins are an important cause of lung damage and, too frequently, patient death. Consequently this book is to be welcomed, since it brings together in one volume much of the basic research into the underlying mechanisms of endotoxin action on the lung and the application of this research to clinical practice. The format of the book reflects the list of contributing authors, a mix of scientists and clinicians, and competently progresses from a discussion of basic knowledge of the toxic properties of endotoxin and its mechanisms of action on the respiratory system, through to the clinical effects and therapeutic manoeuvres for the management of the septic patient. The book ends with speculation about the potential uses of gene therapy in the treatment of such patients. Each chapter is well referenced, and, as we have now come to expect from the series, the quality of production, editorial style and illustrations are all
Mutation Research/Genetic Toxicology and Environmental Mutagenesis, 2000
Occupational exposure to organophosphorus insecticides (OPs), such as diazinon, may be monitored ... more Occupational exposure to organophosphorus insecticides (OPs), such as diazinon, may be monitored by the measurement of the activity of peripheral cholinesterase enzymes, including erythrocyte acetylcholinesterase (EAChE) and plasma or serum cholinesterase (plasma or serum ChE). Exposures have also been measured by the analysis of dialkyl phosphate metabolites of OPs in urine. The potential health risks associated with exposure, especially those of a neurological nature, may then be estimated, and appropriate measures to reduce or eliminate exposures can be implemented. There is evidence that some OP pesticides may have in vivo genotoxic effects, suggesting a possible link with cancer with long term or repeated heavy exposures. This paper describes work performed in 17 subjects with a single or two exposures to a sheep dip containing diazinon. Urine samples revealed OP metabolites dimethylphosphate (DMP), dimethylthiophosphate (DMTP), diethylphosphate (DEP) and diethylthiophosphate (DETP) in 37% of subjects at low levels which were not elevated after exposure. EAChE and plasma ChE were also unchanged before and after exposure, and were similar to those measured in unexposed control groups. Sister chromatid exchanges (SCE), a marker of chromosome damage, was significantly elevated in peripheral blood lymphocytes after exposure compared with before. SCE were unchanged in a group of non-occupationally exposed workers. In vitro studies with both authentic diazinon (98%) and diazinon in a sheep dip formulation (45%) showed increased SCE and decreased replicative indices, suggesting toxic and genotoxic effects of diazinon.
1 Sulphur mustard reacts directly with benzenethiols and cysteine esters in aqueous medium. 2 Ben... more 1 Sulphur mustard reacts directly with benzenethiols and cysteine esters in aqueous medium. 2 Benzenethiols diffuse into lung slices in short term culture. 3 Treatment of lung slices in short term culture with benzenethiols does not protect cellular glutathione from conjugation with sulphur mustard. 4 Following uptake of cysteine ester into lung slices cysteine is elevated but this does not protect cellular glutathione from sulphur mustard.
1 Multiple low doses of the direct acting organopho sphates, ecothiopate, paraoxon and mipafox pr... more 1 Multiple low doses of the direct acting organopho sphates, ecothiopate, paraoxon and mipafox produced persistent and additive inhibition of diaphragm acetylcholinesterase. Paraoxon and mipafox had similar effects on brain acetylcholinesterase. There was greater recovery from inhibition between doses for paraoxon and ecothiopate than for mipafox. 2 Ecothiopate did not inhibit brain acetylcholinesterase but there was a small increase in activity. 3 Mipafox also had a cumulative inhibitory effect on brain neuropathy target esterase. 4 These results have particular implication for the use of multiple low doses of organophosphates occupation- ally by man.
1 The in vitro metabolism ofn-hexane was studied in rat liver, lung, brain and skeletal muscle mi... more 1 The in vitro metabolism ofn-hexane was studied in rat liver, lung, brain and skeletal muscle microsomes and in microsomes prepared from cell lines expressing human cytochrome P-450 2E1 or 2B6. The hydro xylated metabolites ofn-hexane were quantified by gas chromatography-mass spectometry. 2 Rat liver and extensor digitorum longus (EDL, fast- twitch skeletal muscle) microsomes and the CYP 2B6 microsomes produced the pre-neurotoxic metabolite of n-hexane, 2-hexanol as a major metabolite in contrast to the other rat tissues examined. 3 Inhibition of 2- and 3-hexanol production from n- hexane by rat lung microsomes using metyrapone, an inhibitor of cytochrome P-450 2B1 activity, resulted in almost complete inhibition of lung microsomal activ ity. 4 Production of all three hexanols was significantly increased with phenobarbital-induced rat liver micro somes, with a 10-fold increase in 2- and 3-hexanol production. A slight increase in 2-hexanol production with phenobarbital-induced rat ...
1 Interindividual variations in an unexposed population have been defined for five enzymes involv... more 1 Interindividual variations in an unexposed population have been defined for five enzymes involved in organophosphate (OP) toxicity. The enzymes measured were: red blood cell acetylcholinesterase (AChE), lymphocyte neuropathy target esterase (NTE), serum cholinesterase (ChE), serum paraoxonase and serum arylesterase. 2 AChE and arylesterase were normally distributed in the population whilst the distribution of NTE, ChE and paraoxonase deviated significantly from normal. 3 Assay precision and intra-individual variability were measured for each of the enzymes; the effect on interindividual variation was assessed. 4 Variations in enzyme activities between individuals could have profound effects on susceptibility to OP toxicity. Prior determination of these enzymes may be predictive of susceptibility. 5 Lymphocyte NTE has some limitations as an indicator of exposure to neurotoxic OPs.
1 Male albino mice were injected s.c. with an organopho sphate (mipafox, ecothiopate or paraoxon)... more 1 Male albino mice were injected s.c. with an organopho sphate (mipafox, ecothiopate or paraoxon). Treat ments were either a single injection or multiple daily injections with lower doses for 5 or 8 days. At 3 h after injection the activity of brain and diaphragm acet ylcholinesterase and of brain neuropathy target esterase (NTE) was measured. Also measured in the diaphragm at 3 h post dose was the duration of spontaneous miniature endplate potentials (eMEPPs), recorded extracellularly. 2 At 7 and 28 days after dosing action potentials and evoked endplate potentials, produced by stimulating the phrenic nerve at 30 Hz, were recorded in diaphragm muscle. The amplitudes, time-course and latencies of these potentials were measured and the variability of latencies (jitter) was calculated. 3 Single doses of mipafox (20 mg/kg), ecothiopate (0.192 mg/kg) or paraoxon (0.415 mg/kg) in the mouse produced ca. 70% inhibition of diaphragm acetylcho linesterase at 3 h after dosing. All three OPs p...
There is a marked variability in the susceptibility of different cell types in the nervous system... more There is a marked variability in the susceptibility of different cell types in the nervous system to toxic insult. Some of this variation is associated with factors related to the specific functions of the cells, but some also reflects genetic differences in metabolism. It is important that the role of genetic polymorphisms are considered, along with the broader aspects of susceptibility to neurotoxins, in the development of certain neurological disorders.
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Papers by Peter Blain