John Ramsey - Academia.edu (original) (raw)
Papers by John Ramsey
Forensic Toxicology, 2014
ABSTRACT
Frontiers in psychiatry, 2018
3,4-dichloromethylphenidate (3,4-CTMP) and ethylphenidate are new psychoactive substances and ana... more 3,4-dichloromethylphenidate (3,4-CTMP) and ethylphenidate are new psychoactive substances and analogs of the attention deficit medication methylphenidate. Both drugs have been reported on online user fora to induce effects similar to cocaine. In the UK, 3,4-CTMP appeared on the drug market in 2013 and ethylphenidate has been sold since 2010. We aimed to explore the neurochemical effects of these drugs on brain dopamine and noradrenaline efflux. 3,4-CTMP and ethylphenidate, purchased from online vendors, were analyzed using gas chromatography and mass spectroscopy to confirm their identity. Drugs were then tested in adolescent male rat brain slices of the nucleus accumbens and stria terminalis for effects on dopamine and noradrenaline efflux respectively. Fast cyclic voltammetry was used to measure transmitter release. Methylphenidate (10 μM) increased evoked dopamine and noradrenaline efflux by 4- and 2-fold, respectively. 3,4-CTMP (0.1 and 1 μM) increased evoked dopamine and noradr...
Scientific reports, Jan 2, 2017
Wastewater-based epidemiology is an innovative approach to estimate public health status using bi... more Wastewater-based epidemiology is an innovative approach to estimate public health status using biomarker analysis in wastewater. A new compound detected in wastewater can be a potential biomarker of an emerging trend in public health. However, it is currently difficult to select new biomarkers mainly due to limited human metabolism data. This manuscript presents a new framework, which enables the identification and selection of new biomarkers of human exposure to drugs with scarce or unknown human metabolism data. Mephedrone was targeted to elucidate the assessment of biomarkers for emerging drugs of abuse using a four-step analytical procedure. This framework consists of: (i) identification of possible metabolic biomarkers present in wastewater using an in-vivo study; (ii) verification of chiral signature of the target compound; (iii) confirmation of human metabolic residues in in-vivo/vitro studies and (iv) verification of stability of biomarkers in wastewater. Mephedrone was sele...
Scientific reports, Jan 22, 2017
A correction to this article has been published and is linked from the HTML version of this paper... more A correction to this article has been published and is linked from the HTML version of this paper. The error has been fixed in the paper.
BMJ Open Ophthalmology, 2017
Introduction and aims: The use of 'poppers' (volatile alkyl nitrites) has been associated with th... more Introduction and aims: The use of 'poppers' (volatile alkyl nitrites) has been associated with the development of visual symptoms secondary to the development of maculopathy. There are currently no data regarding the prevalence of this condition among poppers users. The aim of this study was to quantify the presence of visual symptoms among poppers users from a global cohort. Design and methods: The Global Drug Survey (GDS) conducts annual anonymous online surveys of drug and alcohol use. Within the 2012 GDS, questions were inserted regarding the presence of visual symptoms in poppers users. Results: The GDS received a total of 21 575 valid responses, with a total of 17 479 from the UK, Australia, USA and Eurozone. Within these areas, 5152 (29.5%) had used poppers within their lifetime and 1322 (7.6%) within the previous year. Of the 'last year' users, when asked the question: 'Do you think poppers use has affected your eyesight?', 29 (2.2%) people responded 'yes', 130 (10.0%) responded 'maybe' and 1146 (87.8%) responded 'no (17 people did not answer). Both multiple choice and free-text responses regarding the nature of visual symptoms correlated with the central visual disturbance that would be expected from maculopathy. There was significant increased symptom prevalence with age (likelihood ratio (2)=19.0; p<0.001). Discussion and conclusions: This study demonstrates that a small, yet significant from a public health perspective, proportion of poppers users have visual symptoms. Clinical correlation is required to determine whether these reported symptoms are due to poppers associated maculopathy, or an alternative cause.
The Science of the total environment, Jan 26, 2016
Concerns about new psychoactive substances (NPS) are increasing due to the rising frequency of se... more Concerns about new psychoactive substances (NPS) are increasing due to the rising frequency of serious intoxications. Analysis of biological fluids (urine) is necessary to get reliable information about the use of these substances. However, it is a challenging task due to the lack of analytical standards and the dynamic character of the NPS market. In the present work, a qualitative screening of NPS was carried out in 23 pooled urine samples collected from a city center in the UK and festivals in the UK and Belgium. The analytical method was based on data-independent acquisition mode using liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. An in-house library was used with >1500 entries corresponding to NPS, classical drugs and metabolites. All samples contained 53 and 28 compounds of interest from the UK and Belgium respectively. Of the different compounds detected, about 70% were confirmed using retention time and product ions while the remaining comp...
Drug testing and analysis, Jan 10, 2016
Variation in ingredients (qualitative variation) and in quantity of active compounds (quantitativ... more Variation in ingredients (qualitative variation) and in quantity of active compounds (quantitative variation) in herbal smoking mixtures containing synthetic cannabinoids has been shown for older products. This can be dangerous to the user, as accurate and reproducible dosing is impossible. In this study, 69 packages containing third-generation cannabinoids of seven brands on the UK market in 2014 were analyzed both qualitatively and quantitatively for variation. When comparing the labels to actual active ingredients identified in the sample, only one brand was shown to be correctly labelled. The other six brands contained less, more, or ingredients other than those listed on the label. Only two brands were inconsistent, containing different active ingredients in different samples. Quantitative variation was assessed both within one package and between several packages. Within-package variation was within a 10% range for five of the seven brands, but two brands showed larger variati...
Lancet, 2007
Page 1. Case Report 1490 www.thelancet.com Vol 369 April 28, 2007 Collapse, reported seizureand ... more Page 1. Case Report 1490 www.thelancet.com Vol 369 April 28, 2007 Collapse, reported seizureand an unexpected pill David M Wood, Paul I Dargan, Jennifer Button, David W Holt, Hanna Ovaska, John Ramsey, Alison L Jones ...
Lancet (London, England), Jan 19, 2016
Nida Research Monograph, Feb 1, 1995
European Journal of Clinical Pharmacology, Jan 16, 2008
British Medical Journal, 1989
To examine the effects of volatile substance abuse on neuropsychological functioning. A sample of... more To examine the effects of volatile substance abuse on neuropsychological functioning. A sample of index children and matched controls were identified by a two stage procedure. Firstly, over 5000 secondary school pupils completed a screening questionnaire, and, secondly, a sample of those who acknowledged volatile substance abuse and a matched sample of those who denied the practice were assessed in detail by means of (a) individually conducted interviews and (b) toxicological examination of breath samples (to exclude those intoxicated at the time of testing). 16 Local education authority secondary schools in London. 160 Pupils aged 13-16: 80 index children who had abused volatile substances to the point of intoxication at least once (confirmed by interview) and 80 controls (confirmed by interview) matched for school year, sex, and ethnic background. Neuropsychological functioning tests provided 35 main outcome measures and were administered blind. Data on educational test performance before substance abuse began were obtained retrospectively. Information on potentially confounding social factors, such as number of siblings, tenure of housing, and parents&amp;#39; socioeconomic and employment state was also obtained. The index children performed significantly less well than the controls in tests of vocabulary, verbal intelligence quotient, full scale intelligence quotient, and a measure of impulsivity. When background social disadvantage was taken into account these differences were no longer significant. There were no significant associations between performance on psychological testing and frequency of abuse, and relations with other aspects of the children&amp;#39;s history of abuse were generally weak or unsystematic. Comparisons between the results of these tests and of educational tests taken before substance abuse produced equivocal findings. Volatile substance abuse, as commonly practised by secondary school pupils, is unlikely to result in neuropsychological impairment.
The Journal of Heart and Lung Transplantation
(Abstract of Poster) This poster demonstrates the application of Expert System computing techniqu... more (Abstract of Poster) This poster demonstrates the application of Expert System computing techniques to the identification of solid dose forms. TICTAC (The Identification Computer for Tablets and Capsules), in menu driven form, was developed in 1981 and is currently operated as a telephone service by the National Poisons Information Service of Guy's Hospital, London. A personal computer (IBM PC compatible) with a hard disc is required. Data is stored on over 7,000 products: ethical, over-the-counter, veterinary, health and herbal medicines are all covered. Data is also stored on the active ingredients and on the manufacturers. A suite of programmes allows manipulation of the data in many ways. An expert system adviser has been incorporated so that a new user can achieve results comparable to an expert. The data is updated weekly as new products become available and old ones change appearance. At present only British products and European products submitted to DHSS for a UK licenc...
British Journal of Dermatology
A case of mepacrine pigmentation occurring in a patient with systemic lupus erythematosus has bee... more A case of mepacrine pigmentation occurring in a patient with systemic lupus erythematosus has been investigated by fluorescent light microscopy, gas--liquid chromatography and analytical electron microscopy. There is strong evidence for the presence of mepacrine itself within the typical granules, which have been shown by electron microscopy to be membrane bound and intracellular. Analytical electron microscopy also showed that the granules contain large quantities of iron and smaller quantities of sulphur.
Medicine, science, and the law, 1991
Experimental work has been undertaken to investigate the potential interference of toluene, 1,1,1... more Experimental work has been undertaken to investigate the potential interference of toluene, 1,1,1-trichloroethane and butane with the evidential breath alcohol testing instruments used in Great Britain (Lion Intoximeter 3000 and Camic Breath Analyser). Volunteers inhaled the volatile substances in an exposure chamber for up to 4 hours, at concentrations of 100, 350 and 600ppm respectively. Subsequently breath was tested on leaving the chamber. No interference was observed with the breath alcohol instruments when the subjects were exposed to toluene and 1,1,1-trichloroethane. A short-term response immediately after exposure was observed for subjects exposed to butane. Further analytical work involving blood and breath samples demonstrated that all three volatile substances were absorbed during exposure and were detectable in blood for at least 3 hours post-exposure. Their elimination post-exposure followed an exponential decay.
Forensic Toxicology, 2014
ABSTRACT
Frontiers in psychiatry, 2018
3,4-dichloromethylphenidate (3,4-CTMP) and ethylphenidate are new psychoactive substances and ana... more 3,4-dichloromethylphenidate (3,4-CTMP) and ethylphenidate are new psychoactive substances and analogs of the attention deficit medication methylphenidate. Both drugs have been reported on online user fora to induce effects similar to cocaine. In the UK, 3,4-CTMP appeared on the drug market in 2013 and ethylphenidate has been sold since 2010. We aimed to explore the neurochemical effects of these drugs on brain dopamine and noradrenaline efflux. 3,4-CTMP and ethylphenidate, purchased from online vendors, were analyzed using gas chromatography and mass spectroscopy to confirm their identity. Drugs were then tested in adolescent male rat brain slices of the nucleus accumbens and stria terminalis for effects on dopamine and noradrenaline efflux respectively. Fast cyclic voltammetry was used to measure transmitter release. Methylphenidate (10 μM) increased evoked dopamine and noradrenaline efflux by 4- and 2-fold, respectively. 3,4-CTMP (0.1 and 1 μM) increased evoked dopamine and noradr...
Scientific reports, Jan 2, 2017
Wastewater-based epidemiology is an innovative approach to estimate public health status using bi... more Wastewater-based epidemiology is an innovative approach to estimate public health status using biomarker analysis in wastewater. A new compound detected in wastewater can be a potential biomarker of an emerging trend in public health. However, it is currently difficult to select new biomarkers mainly due to limited human metabolism data. This manuscript presents a new framework, which enables the identification and selection of new biomarkers of human exposure to drugs with scarce or unknown human metabolism data. Mephedrone was targeted to elucidate the assessment of biomarkers for emerging drugs of abuse using a four-step analytical procedure. This framework consists of: (i) identification of possible metabolic biomarkers present in wastewater using an in-vivo study; (ii) verification of chiral signature of the target compound; (iii) confirmation of human metabolic residues in in-vivo/vitro studies and (iv) verification of stability of biomarkers in wastewater. Mephedrone was sele...
Scientific reports, Jan 22, 2017
A correction to this article has been published and is linked from the HTML version of this paper... more A correction to this article has been published and is linked from the HTML version of this paper. The error has been fixed in the paper.
BMJ Open Ophthalmology, 2017
Introduction and aims: The use of 'poppers' (volatile alkyl nitrites) has been associated with th... more Introduction and aims: The use of 'poppers' (volatile alkyl nitrites) has been associated with the development of visual symptoms secondary to the development of maculopathy. There are currently no data regarding the prevalence of this condition among poppers users. The aim of this study was to quantify the presence of visual symptoms among poppers users from a global cohort. Design and methods: The Global Drug Survey (GDS) conducts annual anonymous online surveys of drug and alcohol use. Within the 2012 GDS, questions were inserted regarding the presence of visual symptoms in poppers users. Results: The GDS received a total of 21 575 valid responses, with a total of 17 479 from the UK, Australia, USA and Eurozone. Within these areas, 5152 (29.5%) had used poppers within their lifetime and 1322 (7.6%) within the previous year. Of the 'last year' users, when asked the question: 'Do you think poppers use has affected your eyesight?', 29 (2.2%) people responded 'yes', 130 (10.0%) responded 'maybe' and 1146 (87.8%) responded 'no (17 people did not answer). Both multiple choice and free-text responses regarding the nature of visual symptoms correlated with the central visual disturbance that would be expected from maculopathy. There was significant increased symptom prevalence with age (likelihood ratio (2)=19.0; p<0.001). Discussion and conclusions: This study demonstrates that a small, yet significant from a public health perspective, proportion of poppers users have visual symptoms. Clinical correlation is required to determine whether these reported symptoms are due to poppers associated maculopathy, or an alternative cause.
The Science of the total environment, Jan 26, 2016
Concerns about new psychoactive substances (NPS) are increasing due to the rising frequency of se... more Concerns about new psychoactive substances (NPS) are increasing due to the rising frequency of serious intoxications. Analysis of biological fluids (urine) is necessary to get reliable information about the use of these substances. However, it is a challenging task due to the lack of analytical standards and the dynamic character of the NPS market. In the present work, a qualitative screening of NPS was carried out in 23 pooled urine samples collected from a city center in the UK and festivals in the UK and Belgium. The analytical method was based on data-independent acquisition mode using liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. An in-house library was used with >1500 entries corresponding to NPS, classical drugs and metabolites. All samples contained 53 and 28 compounds of interest from the UK and Belgium respectively. Of the different compounds detected, about 70% were confirmed using retention time and product ions while the remaining comp...
Drug testing and analysis, Jan 10, 2016
Variation in ingredients (qualitative variation) and in quantity of active compounds (quantitativ... more Variation in ingredients (qualitative variation) and in quantity of active compounds (quantitative variation) in herbal smoking mixtures containing synthetic cannabinoids has been shown for older products. This can be dangerous to the user, as accurate and reproducible dosing is impossible. In this study, 69 packages containing third-generation cannabinoids of seven brands on the UK market in 2014 were analyzed both qualitatively and quantitatively for variation. When comparing the labels to actual active ingredients identified in the sample, only one brand was shown to be correctly labelled. The other six brands contained less, more, or ingredients other than those listed on the label. Only two brands were inconsistent, containing different active ingredients in different samples. Quantitative variation was assessed both within one package and between several packages. Within-package variation was within a 10% range for five of the seven brands, but two brands showed larger variati...
Lancet, 2007
Page 1. Case Report 1490 www.thelancet.com Vol 369 April 28, 2007 Collapse, reported seizureand ... more Page 1. Case Report 1490 www.thelancet.com Vol 369 April 28, 2007 Collapse, reported seizureand an unexpected pill David M Wood, Paul I Dargan, Jennifer Button, David W Holt, Hanna Ovaska, John Ramsey, Alison L Jones ...
Lancet (London, England), Jan 19, 2016
Nida Research Monograph, Feb 1, 1995
European Journal of Clinical Pharmacology, Jan 16, 2008
British Medical Journal, 1989
To examine the effects of volatile substance abuse on neuropsychological functioning. A sample of... more To examine the effects of volatile substance abuse on neuropsychological functioning. A sample of index children and matched controls were identified by a two stage procedure. Firstly, over 5000 secondary school pupils completed a screening questionnaire, and, secondly, a sample of those who acknowledged volatile substance abuse and a matched sample of those who denied the practice were assessed in detail by means of (a) individually conducted interviews and (b) toxicological examination of breath samples (to exclude those intoxicated at the time of testing). 16 Local education authority secondary schools in London. 160 Pupils aged 13-16: 80 index children who had abused volatile substances to the point of intoxication at least once (confirmed by interview) and 80 controls (confirmed by interview) matched for school year, sex, and ethnic background. Neuropsychological functioning tests provided 35 main outcome measures and were administered blind. Data on educational test performance before substance abuse began were obtained retrospectively. Information on potentially confounding social factors, such as number of siblings, tenure of housing, and parents&amp;#39; socioeconomic and employment state was also obtained. The index children performed significantly less well than the controls in tests of vocabulary, verbal intelligence quotient, full scale intelligence quotient, and a measure of impulsivity. When background social disadvantage was taken into account these differences were no longer significant. There were no significant associations between performance on psychological testing and frequency of abuse, and relations with other aspects of the children&amp;#39;s history of abuse were generally weak or unsystematic. Comparisons between the results of these tests and of educational tests taken before substance abuse produced equivocal findings. Volatile substance abuse, as commonly practised by secondary school pupils, is unlikely to result in neuropsychological impairment.
The Journal of Heart and Lung Transplantation
(Abstract of Poster) This poster demonstrates the application of Expert System computing techniqu... more (Abstract of Poster) This poster demonstrates the application of Expert System computing techniques to the identification of solid dose forms. TICTAC (The Identification Computer for Tablets and Capsules), in menu driven form, was developed in 1981 and is currently operated as a telephone service by the National Poisons Information Service of Guy's Hospital, London. A personal computer (IBM PC compatible) with a hard disc is required. Data is stored on over 7,000 products: ethical, over-the-counter, veterinary, health and herbal medicines are all covered. Data is also stored on the active ingredients and on the manufacturers. A suite of programmes allows manipulation of the data in many ways. An expert system adviser has been incorporated so that a new user can achieve results comparable to an expert. The data is updated weekly as new products become available and old ones change appearance. At present only British products and European products submitted to DHSS for a UK licenc...
British Journal of Dermatology
A case of mepacrine pigmentation occurring in a patient with systemic lupus erythematosus has bee... more A case of mepacrine pigmentation occurring in a patient with systemic lupus erythematosus has been investigated by fluorescent light microscopy, gas--liquid chromatography and analytical electron microscopy. There is strong evidence for the presence of mepacrine itself within the typical granules, which have been shown by electron microscopy to be membrane bound and intracellular. Analytical electron microscopy also showed that the granules contain large quantities of iron and smaller quantities of sulphur.
Medicine, science, and the law, 1991
Experimental work has been undertaken to investigate the potential interference of toluene, 1,1,1... more Experimental work has been undertaken to investigate the potential interference of toluene, 1,1,1-trichloroethane and butane with the evidential breath alcohol testing instruments used in Great Britain (Lion Intoximeter 3000 and Camic Breath Analyser). Volunteers inhaled the volatile substances in an exposure chamber for up to 4 hours, at concentrations of 100, 350 and 600ppm respectively. Subsequently breath was tested on leaving the chamber. No interference was observed with the breath alcohol instruments when the subjects were exposed to toluene and 1,1,1-trichloroethane. A short-term response immediately after exposure was observed for subjects exposed to butane. Further analytical work involving blood and breath samples demonstrated that all three volatile substances were absorbed during exposure and were detectable in blood for at least 3 hours post-exposure. Their elimination post-exposure followed an exponential decay.