46 results on '"Kemp, S"'
Search Results
2. L’Invention de l’inconscient par le récit de fiction, 1850–1895 by Romain Enriquez (review)
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Kemp, Simon
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- 2023
3. The Post-War Experimental Novel: British and French Fiction, 1945–75 by Andrew Hodgson (review)
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Kemp, Simon
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- 2023
4. Devenirs du romanesque: les écritures aventureuses de Jean Echenoz, Jean Rolin et Patrick Deville par Anne Sennhauser (review)
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Kemp, Simon
- Published
- 2021
5. "A whole theater of others": Amateur Acting and Immersive Spectatorship in the Digital Shakespeare Game Play the Knave
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Bloom, Gina, Kemp, Sawyer, Toothman, Nicholas, and Buswell, Evan
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- 2017
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6. Georges Perec’s Geographies: Material, Performative and Textual Spaces ed. by Charles Forsdick, Andrew Leak and Richard Phillips (review)
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Kemp, Simon
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- 2021
7. Désirs de disparaître: une traversée du roman français contemporain par Dominique Rabaté (review)
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Kemp, Simon
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- 2017
8. Darrieussecq's Mind
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Kemp, Simon
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- 2008
9. Le Défi du roman: narration et engagement oblique à l’ère postmoderne by Elisa Bricco (review)
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Kemp, Simon
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- 2016
10. Narrations d’un nouveau siècle: romans et récits français (2001–2010) ed. by Bruno Blankeman and Barbara Havercroft (review)
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Kemp, Simon
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- 2014
11. La Relation écriture–lecture. Cheminements contemporains: Éric Chevillard, Pierre Michon, Christian Gailly, Hélène Lenoir (review)
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Kemp, Simon
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- 2011
12. Frédéric Beigbeder et ses doubles (review)
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Kemp, Simon
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- 2010
13. Portraits de villes: Marches et cartes. La Représentation urbaine dans les discours contemporains (review)
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Kemp, Simon
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- 2009
14. Fiction Now: The French Novel in the Twenty-First Century (review)
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Kemp, Simon
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- 2009
15. Écritures contemporaines 10: nouvelles écritures littéraires de l’Histoire (review)
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Kemp, Simon
- Published
- 2011
16. Case Report: the transcatheter extraction of an atrial mass (TEXAS) technique.
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Ahmad U, Prayaga S, Kemp S, and Goswami N
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Background: Intracardiac masses are historically treated with surgery. As percutaneous technologies continue to evolve, non-surgical techniques for mass removal may become options. We present a case of a woman with a large right atrial mass that was percutaneously removed en bloc without surgery., Case Summary: A 77-year-old woman presents with a 40 mm right atrial mass. The mass was increasing in size, and she preferred to avoid surgical removal. The tumour was removed percutaneously from the femoral vein using a large suction cannula in combination with transection of the stalk using an electrified snare. The case was complicated by a haemopericardium that was treated successfully by injecting a haemostatic matrix into the pericardial space. The pathology returned papillary fibroelastoma., Discussion: The TEXAS technique used to remove the right atrial mass in this case is a modification of a previously described technique (SEATTLE procedure). Using this method, we were able to remove a 40 mm tumour from the right atrium without surgery. This is the largest reported intracardiac tumour that has been removed en bloc percutaneously. Percutaneous removal of right atrial tumours appears feasible, although this may be limited to smaller tumours based on the results of our case., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)
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- 2024
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17. Active elite rugby participation is associated with altered precentral cortical thickness.
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Parker TD, Zimmerman KA, Laverse E, Bourke NJ, Graham NSN, Mallas EJ, Heslegrave A, Zetterberg H, Kemp S, Morris HR, and Sharp DJ
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There is growing concern that elite rugby participation may negatively influence brain health, but the underlying mechanisms are unclear. Cortical thickness is a widely applied biomarker of grey matter structure, but there is limited research into how it may be altered in active professional rugby players. Cross-sectional MRI data from 44 active elite rugby players, including 21 assessed within 1 week of head injury, and 47 healthy controls were analysed. We investigated how active elite rugby participation with and without sub-acute traumatic brain injury influenced grey matter structure using whole cortex and region of interest cortical thickness analyses. Relationships between cortical thickness and biomarkers of traumatic brain injury, including fractional anisotropy, plasma neurofilament light and glial fibrillary acidic protein, were also examined. In whole-cortex analyses, precentral cortical thickness in the right hemisphere was lower in rugby players compared with controls, which was due to reductions in non-injured players. Post hoc region of interest analyses showed non-injured rugby players had reduced cortical thickness in the inferior precentral sulcal thickness bilaterally ( P = 0.005) and the left central sulcus ( P = 0.037) relative to controls. In contrast, players in the sub-acute phase of mild traumatic brain injury had higher inferior precentral sulcal cortical thickness in the right hemisphere ( P = 0.015). Plasma glial fibrillary acidic protein, a marker of astrocyte activation, was positively associated with right inferior precentral sulcal cortical thickness in injured rugby players ( P = 0.0012). Elite rugby participation is associated with localized alterations in cortical thickness, specifically in sulcal motor regions. Sub-acute changes after mild traumatic brain injury are associated with evidence of astrocytic activation. The combination of cortical thickness and glial fibrillary acidic protein may be useful in understanding the pathophysiological relationship between sporting head injury and brain health., Competing Interests: D.J.S. has received an honorarium from the Rugby Football Union for participation in an expert concussion panel, which was used to support his research. He has also received an honorarium from the Wellcome Trust and is the principal investigator of the advanced BRAIN (BiomaRker, Advanced Imaging and Neurocognitive assessment) health clinic; a specialist clinic for retired elite rugby and football players with concerns regarding their brain health, which is funded by, but independently run from, the Rugby Football Union, Premiership Rugby and the English Football Association. T.D.P., K.A.Z. and N.S.N.G. are members of the advanced BRAIN health clinic study team. H.Z. has served at scientific advisory boards and/or as a consultant for Abbvie, Acumen, Alector, ALZPath, Annexon, Apellis, Artery Therapeutics, AZTherapies, CogRx, Denali, Eisai, Nervgen, Novo Nordisk, Passage Bio, Pinteon Therapeutics, Red Abbey Labs, reMYND, Roche, Samumed, Siemens Healthineers, Triplet Therapeutics and Wave, has given lectures in symposia sponsored by Cellectricon, Fujirebio, Alzecure, Biogen and Roche, and is a co-founder of Brain Biomarker Solutions in Gothenburg AB (BBS), which is a part of the GU Ventures Incubator Program (outside submitted work). H.R.M. is employed by UCL. He reports paid consultancy from Biogen, UCB, Abbvie, Denali, Biohaven and Lundbeck; lecture fees/honoraria from Biogen, UCB, C4X Discovery, GE-Healthcare, Wellcome Trust and Movement Disorders Society; and research grants from Parkinson’s UK, Cure Parkinson’s Trust, PSP Association, CBD Solutions, Drake Foundation and Medical Research Council. H.R.M. is a co-applicant on a patent application related to C9ORF72—Method for diagnosing a neurodegenerative disease (PCT/GB2012/052140). S.K. is employed as the Medical Services Director for the Rugby Football Union. All other authors have no competing interests., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Guarantors of Brain.)
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- 2023
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18. The biomechanical signature of loss of consciousness: computational modelling of elite athlete head injuries.
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Zimmerman KA, Cournoyer J, Lai H, Snider SB, Fischer D, Kemp S, Karton C, Hoshizaki TB, Ghajari M, and Sharp DJ
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- Humans, Consciousness, Head, Athletes, Unconsciousness, Computer Simulation, Biomechanical Phenomena, Craniocerebral Trauma complications, Brain Concussion etiology, Movement Disorders complications
- Abstract
Sports related head injuries can cause transient neurological events including loss of consciousness and dystonic posturing. However, it is unknown why head impacts that appear similar produce distinct neurological effects. The biomechanical effect of impacts can be estimated using computational models of strain within the brain. Here, we investigate the strain and strain rates produced by professional American football impacts that led to loss of consciousness, posturing or no neurological signs. We reviewed 1280 National Football League American football games and selected cases where the team's medical personnel made a diagnosis of concussion. Videos were then analysed for signs of neurological events. We identified 20 head impacts that showed clear video signs of loss of consciousness and 21 showing clear abnormal posturing. Forty-one control impacts were selected where there was no observable evidence of neurological signs, resulting in 82 videos of impacts for analysis. Video analysis was used to guide physical reconstructions of these impacts, allowing us to estimate the impact kinematics. These were then used as input to a detailed 3D high-fidelity finite element model of brain injury biomechanics to estimate strain and strain rate within the brain. We tested the hypotheses that impacts producing loss of consciousness would be associated with the highest biomechanical forces, that loss of consciousness would be associated with high forces in brainstem nuclei involved in arousal and that dystonic posturing would be associated with high forces in motor regions. Impacts leading to loss of consciousness compared to controls produced higher head acceleration (linear acceleration; 81.5 g ± 39.8 versus 47.9 ± 21.4; P = 0.004, rotational acceleration; 5.9 krad/s2 ± 2.4 versus 3.5 ± 1.6; P < 0.001) and in voxel-wise analysis produced larger brain deformation in many brain regions, including parts of the brainstem and cerebellum. Dystonic posturing was also associated with higher deformation compared to controls, with brain deformation observed in cortical regions that included the motor cortex. Loss of consciousness was specifically associated with higher strain rates in brainstem regions implicated in maintenance of consciousness, including following correction for the overall severity of impact. These included brainstem nuclei including the locus coeruleus, dorsal raphé and parabrachial complex. The results show that in head impacts producing loss of consciousness, brain deformation is disproportionately seen in brainstem regions containing nuclei involved in arousal, suggesting that head impacts produce loss of consciousness through a biomechanical effect on key brainstem nuclei involved in the maintenance of consciousness., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Guarantors of Brain.)
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- 2023
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19. Markhor-derived Introgression of a Genomic Region Encompassing PAPSS2 Confers High-altitude Adaptability in Tibetan Goats.
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Li C, Wu Y, Chen B, Cai Y, Guo J, Leonard AS, Kalds P, Zhou S, Zhang J, Zhou P, Gan S, Jia T, Pu T, Suo L, Li Y, Zhang K, Li L, Purevdorj M, Wang X, Li M, Wang Y, Liu Y, Huang S, Sonstegard T, Wang MS, Kemp S, Pausch H, Chen Y, Han JL, Jiang Y, and Wang X
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- Animals, Ultraviolet Rays, Genomics, Goats genetics, Genome-Wide Association Study
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Understanding the genetic mechanism of how animals adapt to extreme conditions is fundamental to determine the relationship between molecular evolution and changing environments. Goat is one of the first domesticated species and has evolved rapidly to adapt to diverse environments, including harsh high-altitude conditions with low temperature and poor oxygen supply but strong ultraviolet radiation. Here, we analyzed 331 genomes of domestic goats and wild caprid species living at varying altitudes (high > 3000 m above sea level and low < 1200 m), along with a reference-guided chromosome-scale assembly (contig-N50: 90.4 Mb) of a female Tibetan goat genome based on PacBio HiFi long reads, to dissect the genetic determinants underlying their adaptation to harsh conditions on the Qinghai-Tibetan Plateau (QTP). Population genomic analyses combined with genome-wide association studies (GWAS) revealed a genomic region harboring the 3'-phosphoadenosine 5'-phosphosulfate synthase 2 (PAPSS2) gene showing strong association with high-altitude adaptability (PGWAS = 3.62 × 10-25) in Tibetan goats. Transcriptomic data from 13 tissues revealed that PAPSS2 was implicated in hypoxia-related pathways in Tibetan goats. We further verified potential functional role of PAPSS2 in response to hypoxia in PAPSS2-deficient cells. Introgression analyses suggested that the PAPSS2 haplotype conferring the high-altitude adaptability in Tibetan goats originated from a recent hybridization between goats and a wild caprid species, the markhor (Capra falconeri). In conclusion, our results uncover a hitherto unknown contribution of PAPSS2 to high-altitude adaptability in Tibetan goats on QTP, following interspecific introgression and natural selection., (© The Author(s) 2022. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.)
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- 2022
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20. Functional Cognitive Disorder: Differential Diagnosis of Common Clinical Presentations.
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Kemp S, Kapur N, Graham CD, and Reuber M
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- Cognition, Diagnosis, Differential, Humans, Neuropsychological Tests, Cognition Disorders diagnosis, Cognition Disorders etiology, Cognition Disorders psychology, Malingering diagnosis, Malingering psychology
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Background: Cognitive symptoms in the absence of neurological disease are common. Functional cognitive disorder (FCD) has been conceptualized as a cognitive subtype of functional neurological disorder. Although FCD is understood as different from exaggerated or feigned cognitive complaints, previous accounts have provided little practical advice on how FCD can be separated from factitious or malingered cognitive complaints. Also, the distinction of FCD from other medical or mental health disorders that impact on cognition is an area of ongoing study and debate. Diagnostic precision is important to prevent iatrogenesis and for the development of needed treatment protocols., Method: We summarize the current literature and present seven anonymized case vignettes to characterize the challenges in this area and develop proposals for solutions., Results/conclusions: Recognizing the limitations of categorical diagnostic systems, we position FCD as distinct from feigning and cognitive symptoms of psychiatric disorders, although with overlapping features. We set out typical clinical features and neuropsychological profiles for each category of cognitive disorder and a statistical method to analyze performance validity tests/effort tests to assist in determining feigned or invalid responding., (© The Author(s) 2022. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2022
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21. White matter abnormalities in active elite adult rugby players.
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Zimmerman KA, Laverse E, Samra R, Yanez Lopez M, Jolly AE, Bourke NJ, Graham NSN, Patel MC, Hardy J, Kemp S, Morris HR, and Sharp DJ
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The recognition, diagnosis and management of mild traumatic brain injuries are difficult and confusing. It is unclear how the severity and number of injuries sustained relate to brain injuries, such as diffuse axonal injury, diffuse vascular injury and progressive neurodegeneration. Advances in neuroimaging techniques enable the investigation of neuropathologies associated with acute and long-term effects of injury. Head injuries are the most commonly reported injury seen during professional rugby. There is increased vigilance for the immediate effects of these injuries in matches, but there has been surprisingly little research investigating the longer-term effects of rugby participation. Here, we present a longitudinal observational study investigating the relationship of exposure to rugby participation and sub-acute head injuries in professional adult male and female rugby union and league players using advanced MRI. Diffusion tensor imaging and susceptibility weighted imaging was used to assess white matter structure and evidence of axonal and diffuse vascular injury. We also studied changes in brain structure over time using Jacobian Determinant statistics extracted from serial volumetric imaging. We tested 41 male and 3 female adult elite rugby players, of whom 21 attended study visits after a head injury, alongside 32 non-sporting controls, 15 non-collision-sport athletic controls and 16 longitudinally assessed controls. Eighteen rugby players participated in the longitudinal arm of the study, with a second visit at least 6 months after their first scan. Neuroimaging evidence of either axonal injury or diffuse vascular injury was present in 23% (10/44) of players. In the non-acutely injured group of rugby players, abnormalities of fractional anisotropy and other diffusion measures were seen. In contrast, non-collision-sport athletic controls were not classified as showing abnormalities. A group level contrast also showed evidence of sub-acute injury using diffusion tensor imaging in rugby players. Examination of longitudinal imaging revealed unexpected reductions in white matter volume in the elite rugby players studied. These changes were not related to self-reported head injury history or neuropsychological test scores and might indicate excess neurodegeneration in white matter tracts affected by injury. Taken together, our findings suggest an association of participation in elite adult rugby with changes in brain structure. Further well-designed large-scale studies are needed to understand the impact of both repeated sports-related head impacts and head injuries on brain structure, and to clarify whether the abnormalities we have observed are related to an increased risk of neurodegenerative disease and impaired neurocognitive function following elite rugby participation., (© The Author(s) (2021). Published by Oxford University Press on behalf of the Guarantors of Brain.)
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- 2021
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22. Functional cognitive disorder: dementia's blind spot.
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Kapur N, Kemp S, and Baker G
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- Cognition, Humans, Cognition Disorders etiology, Dementia complications
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- 2021
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23. Linking soils and human health: geospatial analysis of ground-sampled soil data in relation to community-level podoconiosis data in North West Cameroon.
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Gislam H, Burnside NG, Brolly M, Deribe K, Davey G, Wanji S, Suh CE, Kemp SJ, Watts MJ, and Le Blond JS
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- Cameroon epidemiology, Ethiopia, Humans, Prevalence, Shoes, Soil, Elephantiasis epidemiology
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Background: Podoconiosis is a form of leg swelling, which arises when individuals are exposed over time to red clay soil formed from alkaline volcanic rock. The exact causal agent of the disease is unknown. This study investigates associations between podoconiosis disease data and ground-sampled soil data from North West Cameroon., Methods: The mineralogy and elemental concentrations were measured in the soil samples and the data were spatially interpolated. Mean soil values were calculated from a 3 km buffer region around the prevalence data points to perform statistical analysis. Analysis included Spearman's rho correlation, binary logistic regression and principal component analysis (PCA)., Results: Six elements, barium, beryllium, potassium, rubidium, strontium and thallium, as well as two minerals, potassium feldspar and quartz, were identified as statistically related to podoconiosis. PCA did not show distinct separation between the spatial locations with or without recorded cases of podoconiosis, indicating that other factors such as shoe-wearing behaviour and genetics may significantly influence podoconiosis occurrence and prevalence in North West Cameroon., Conclusion: Several soil variables were statistically significantly related to podoconiosis. To further the current study, future investigations will look at the inflammatory pathway response of cells after exposure to these variables., (© The Author(s) 2020. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene.)
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- 2020
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24. The Inflammatory Bowel Disease Drug Azathioprine Induces Autophagy via mTORC1 and the Unfolded Protein Response Sensor PERK.
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Hooper KM, Casanova V, Kemp S, Staines KA, Satsangi J, Barlow PG, Henderson P, and Stevens C
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- Adolescent, Case-Control Studies, Child, Escherichia coli drug effects, Escherichia coli Infections drug therapy, Escherichia coli Infections metabolism, Escherichia coli Infections microbiology, Female, Humans, Immunosuppressive Agents pharmacology, Inflammatory Bowel Diseases drug therapy, Inflammatory Bowel Diseases metabolism, Leukocytes, Mononuclear drug effects, Leukocytes, Mononuclear metabolism, Leukocytes, Mononuclear pathology, Male, Mechanistic Target of Rapamycin Complex 1 genetics, eIF-2 Kinase genetics, Autophagy, Azathioprine pharmacology, Escherichia coli growth & development, Inflammatory Bowel Diseases pathology, Mechanistic Target of Rapamycin Complex 1 metabolism, Unfolded Protein Response drug effects, eIF-2 Kinase metabolism
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Background: Genetic studies have strongly linked autophagy to Crohn's disease (CD), and stimulating autophagy in CD patients may be therapeutically beneficial. The aim of this study was to evaluate the effect of current inflammatory bowel disease (IBD) drugs on autophagy and investigate molecular mechanisms of action and functional outcomes in relation to this cellular process., Methods: Autophagy marker LC3 was evaluated by confocal fluorescence microscopy and flow cytometry. Drug mechanism of action was investigated by polymerase chain reaction (PCR) array with changes in signaling pathways examined by immunoblot and quantitative reverse transcription PCR (RT-qPCR). Clearance of adherent-invasive Escherichia coli (AIEC) and levels of pro-inflammatory cytokine tumor necrosis factor alpha (TNFα) were evaluated by gentamicin protection assays and RT-qPCR, respectively. The marker LC3 was analyzed in peripheral blood mononuclear cells (PBMCs) from pediatric patients by flow cytometry., Results: Azathioprine induces autophagy via mechanisms involving modulation of mechanistic target of rapamycin (mTORC1) signaling and stimulation of the unfolded protein response (UPR) sensor PERK. Induction of autophagy with azathioprine correlated with the enhanced clearance of AIEC and dampened AIEC-induced increases in TNFα. Azathioprine induced significant increase in autophagosome bound LC3-II in PBMC populations ex vivo, supporting in vitro findings. In patients, the CD-associated ATG16L1 T300A single-nucleotide polymorphism did not attenuate azathioprine induction of autophagy., Conclusions: Modulation of autophagy via mTORC1 and the UPR may contribute to the therapeutic efficacy of azathioprine in IBD., (© 2019 Crohn’s & Colitis Foundation. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2019
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25. Progression of myelopathy in males with adrenoleukodystrophy: towards clinical trial readiness.
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Huffnagel IC, van Ballegoij WJC, van Geel BM, Vos JMBW, Kemp S, and Engelen M
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- Adolescent, Adrenoleukodystrophy epidemiology, Adult, Aged, Cohort Studies, Follow-Up Studies, Humans, Male, Middle Aged, Prospective Studies, Spinal Cord Diseases epidemiology, Young Adult, Adrenoleukodystrophy diagnostic imaging, Adrenoleukodystrophy physiopathology, Disease Progression, Spinal Cord Diseases diagnostic imaging, Spinal Cord Diseases physiopathology
- Abstract
Males with adrenoleukodystrophy develop progressive myelopathy causing severe disability later in life. No treatment is currently available, but new disease-modifying therapies are under development. Knowledge of the natural history of the myelopathy is of paramount importance for evaluation of these therapies in clinical trials, but prospective data on disease progression are lacking. We performed a prospective observational cohort study to quantify disease progression over 2 years of follow-up. Signs and symptoms, functional outcome measures and patient-reported outcomes were assessed at baseline, 1 and 2 years of follow-up. We included 46 male adrenoleukodystrophy patients (median age 45.5 years, range 16-71). Frequency of myelopathy at baseline increased with age from 30.8% (<30 years) to 94.7% (>50 years). Disease progression was measured in the patients who were symptomatic at baseline (n = 24) or became symptomatic during follow-up (n = 1). Significant progression was detected with the functional outcome measures and quantitative vibration measurements. Over 2 years of follow-up, Expanded Disability Status Score increased by 0.34 points (P = 0.034), Severity Scoring system for Progressive Myelopathy decreased by 2.78 points (P = 0.013), timed up-and-go increased by 0.82 s (P = 0.032) and quantitative vibration measurement at the hallux decreased by 0.57 points (P = 0.040). Changes over 1-year follow-up were not significant, except for the 6-minute walk test that decreased by 19.67 meters over 1 year (P = 0.019). None of the patient-reported outcomes were able to detect disease progression. Our data show that progression of myelopathy in adrenoleukodystrophy can be quantified using practical and clinically relevant outcome measures. These results will help in the design of clinical trials and the development of new biomarkers for the myelopathy of adrenoleukodystrophy.10.1093/brain/awy299_video1awy299media15995811923001.
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- 2019
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26. The Natural History of Adrenal Insufficiency in X-Linked Adrenoleukodystrophy: An International Collaboration.
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Huffnagel IC, Laheji FK, Aziz-Bose R, Tritos NA, Marino R, Linthorst GE, Kemp S, Engelen M, and Eichler F
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- Adolescent, Adrenal Insufficiency epidemiology, Adrenoleukodystrophy epidemiology, Adult, Aged, Biomarkers, Brain Diseases epidemiology, Brain Diseases etiology, Child, Child, Preschool, Endpoint Determination, Female, Humans, Infant, Infant, Newborn, Male, Middle Aged, Prevalence, Retrospective Studies, Risk Assessment, Spinal Cord Diseases etiology, Survival Analysis, Young Adult, Adrenal Insufficiency etiology, Adrenal Insufficiency pathology, Adrenoleukodystrophy complications, Adrenoleukodystrophy pathology
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Context: Primary adrenal insufficiency is an important clinical manifestation of X-linked adrenoleukodystrophy (ALD). Other manifestations include spinal cord disease and/or inflammatory demyelinating cerebral disease. Implementation of newborn screening requires natural history data to develop follow-up recommendations., Objective: To delineate the natural history of adrenal insufficiency in male patients with ALD and to assess associations between the risk for developing adrenal insufficiency, spinal cord disease, or cerebral disease and plasma C26:0/C22:0 and C24:0/C22:0 ratios, which are diagnostic biomarkers for ALD., Design: Retrospective review of medical records., Setting: Two international tertiary referral centers of expertise for ALD., Patients: Male patients with ALD followed at the centers between 2002 and 2016., Main Outcome Measures: The primary endpoint was adrenal insufficiency; secondary endpoints were spinal cord and cerebral disease., Results: Data on 159 male patients was available. The probability of developing adrenal insufficiency was described with survival analysis. Median time until adrenal insufficiency was 14 years (95% CI, 9.70 to 18.30 years). The cumulative proportion of patients who developed adrenal insufficiency was age-dependent and highest in early childhood [0 to 10 years, 46.8% (SEM 0.041%); 11 to 40 years, 28.6% (SEM, 0.037%); >40 years, 5.6% (SEM, 0.038%)]. No association between clinical manifestations and plasma ratios was detected with Cox model or Spearman correlation., Conclusions: Lifetime prevalence of adrenal insufficiency in male patients with ALD is ~80%. Adrenal insufficiency risk is time-dependent and warrants age-dependent follow-up. Besides on-demand testing if symptoms manifest, we suggest a minimum of adrenal testing every 4 to 6 months for patients age ≤10 years, annual testing for those age 11 to 40 years, and solely on-demand testing for those age >40 years.
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- 2019
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27. Reply: Age-dependent penetrance among females with X-linked adrenoleukodystrophy.
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Engelen M, Barbier M, Dijkstra IM, Schür R, de Bie RM, Verhamme C, Dijkgraaf MG, Aubourg PA, Wanders RJ, van Geel BM, de Visser M, Poll-The BT, and Kemp S
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- Female, Humans, ATP-Binding Cassette Transporters genetics, Adrenoleukodystrophy physiopathology, Peripheral Nervous System Diseases physiopathology, Spinal Cord Diseases physiopathology
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- 2015
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28. X-linked adrenoleukodystrophy in women: a cross-sectional cohort study.
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Engelen M, Barbier M, Dijkstra IM, Schür R, de Bie RM, Verhamme C, Dijkgraaf MG, Aubourg PA, Wanders RJ, van Geel BM, de Visser M, Poll-The BT, and Kemp S
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- ATP Binding Cassette Transporter, Subfamily D, Member 1, Adrenoleukodystrophy blood, Adrenoleukodystrophy complications, Adrenoleukodystrophy genetics, Adult, Age Factors, Aged, Cohort Studies, Cross-Sectional Studies, Evoked Potentials physiology, Female, Heterozygote, Humans, Middle Aged, Peripheral Nervous System Diseases etiology, Prospective Studies, Spinal Cord Diseases etiology, X Chromosome Inactivation genetics, Young Adult, ATP-Binding Cassette Transporters genetics, Adrenoleukodystrophy physiopathology, Peripheral Nervous System Diseases physiopathology, Spinal Cord Diseases physiopathology
- Abstract
X-linked adrenoleukodystrophy is the most common peroxisomal disorder. The disease is caused by mutations in the ABCD1 gene that encodes the peroxisomal transporter of very long-chain fatty acids. A defect in the ABCD1 protein results in elevated levels of very long-chain fatty acids in plasma and tissues. The clinical spectrum in males with X-linked adrenoleukodystrophy has been well described and ranges from isolated adrenocortical insufficiency and slowly progressive myelopathy to devastating cerebral demyelination. As in many X-linked diseases, it was assumed that female carriers remain asymptomatic and only a few studies addressed the phenotype of X-linked adrenoleukodystrophy carriers. These studies, however, provided no information on the prevalence of neurological symptoms in the entire population of X-linked adrenoleukodystrophy carriers, since data were acquired in small groups and may be biased towards women with symptoms. Our primary goal was to investigate the symptoms and their frequency in X-linked adrenoleukodystrophy carriers. The secondary goal was to determine if the X-inactivation pattern of the ABCD1 gene was associated with symptomatic status. We included 46 X-linked adrenoleukodystrophy carriers in a prospective cross-sectional cohort study. Our data show that X-linked adrenoleukodystrophy carriers develop signs and symptoms of myelopathy (29/46, 63%) and/or peripheral neuropathy (26/46, 57%). Especially striking was the occurrence of faecal incontinence (13/46, 28%). The frequency of symptomatic women increased sharply with age (from 18% in women <40 years to 88% in women >60 years of age). Virtually all (44/45, 98%) X-linked adrenoleukodystrophy carriers had increased very long-chain fatty acids in plasma and/or fibroblasts, and/or decreased very long-chain fatty acids beta-oxidation in fibroblasts. We did not find an association between the X-inactivation pattern and symptomatic status. We conclude that X-linked adrenoleukodystrophy carriers develop an adrenomyeloneuropathy-like phenotype and there is a strong association between symptomatic status and age. X-linked adrenoleukodystrophy should be considered in the differential diagnosis in women with chronic myelopathy and/or peripheral neuropathy (especially with early faecal incontinence). ABCD1 mutation analysis deserves a place in diagnostic protocols for chronic non-compressive myelopathy.
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- 2014
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29. A randomized comparative trial of generalized vs targeted physiotherapy in the management of childhood hypermobility.
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Kemp S, Roberts I, Gamble C, Wilkinson S, Davidson JE, Baildam EM, Cleary AG, McCann LJ, and Beresford MW
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- Adolescent, Arthrometry, Articular, Child, Female, Humans, Joint Instability physiopathology, Male, Muscle Strength, Pain Measurement methods, Range of Motion, Articular, Treatment Outcome, Exercise Therapy methods, Joint Instability rehabilitation
- Abstract
Objective: Joint hypermobility, common in childhood, can be associated with severe pain and significant morbidity. Physiotherapy, the mainstay of treatment, lacks a robust evidence base. This study is aimed at determining the best physiotherapy intervention in managing childhood hypermobility., Methods: A prospective randomized comparative trial (RCT) compared a 6-week generalized programme, improving muscular strength and fitness, with a targeted programme aimed at correcting motion control of symptomatic joints. Patients were assessed on symptom scores (pain/global-impact), function, muscle strength and fitness., Results: Fifty-seven children, aged 7-16 years with symptomatic hypermobility, were randomly assign to receive a targeted (T; n = 30) or generalized (G; n = 27) programme. Statistically significant improvements were demonstrated in both the children's and parental pain scores across both the randomized groups between baseline and follow-up assessments (P < 0.05). However, the difference in improvement between the groups was not statistically significant. Child's assessment of change in pain score: mean difference (95% CI) T - G, 3.97 (-15.59, 20.85) at the end of treatment and 9.41 at 3-month follow-up (-17.42, 36.24). At the end of treatment, parental assessment of change in pain score, T - G was: -0.27 (-15.05, 14.50) and at 3-month follow-up it was: -9.48 (-26.40, 7.43). Change in parental global assessment was statistically significant, in favour of targeted physiotherapy at final assessment: -21.29 (-40.03, -2.55)., Conclusion: This is the first physiotherapy RCT for treating hypermobility. It demonstrated significant and sustained reduction in pain when both groups were combined, but did not detect any difference between the groups. This study provides normative and methodological data for future studies of hypermobility., Trial Registration: Current Controlled Trials, www.controlled-trials.com, ISRCTN58523390.
- Published
- 2010
- Full Text
- View/download PDF
30. A systematic strategy for large-scale analysis of genotype phenotype correlations: identification of candidate genes involved in African trypanosomiasis.
- Author
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Fisher P, Hedeler C, Wolstencroft K, Hulme H, Noyes H, Kemp S, Stevens R, and Brass A
- Subjects
- Animals, Base Sequence, Carrier Proteins genetics, Co-Repressor Proteins, Genotype, Immunity, Innate genetics, Intracellular Signaling Peptides and Proteins genetics, Mice, Molecular Chaperones, Molecular Sequence Data, Nuclear Proteins genetics, Oligonucleotide Array Sequence Analysis, Phenotype, Sequence Alignment, Software, Trypanosomiasis, African metabolism, Gene Expression Profiling, Genetic Predisposition to Disease, Quantitative Trait Loci, Trypanosomiasis, African genetics
- Abstract
It is increasingly common to combine Microarray and Quantitative Trait Loci data to aid the search for candidate genes responsible for phenotypic variation. Workflows provide a means of systematically processing these large datasets and also represent a framework for the re-use and the explicit declaration of experimental methods. In this article, we highlight the issues facing the manual analysis of microarray and QTL data for the discovery of candidate genes underlying complex phenotypes. We show how automated approaches provide a systematic means to investigate genotype-phenotype correlations. This methodology was applied to a use case of resistance to African trypanosomiasis in the mouse. Pathways represented in the results identified Daxx as one of the candidate genes within the Tir1 QTL region. Subsequent re-sequencing in Daxx identified a deletion of an amino acid, identified in susceptible mouse strains, in the Daxx-p53 protein-binding region. This supports recent experimental evidence that apoptosis could be playing a role in the trypanosomiasis resistance phenotype. Workflows developed in this investigation, including a guide to loading and executing them with example data, are available at http://workflows.mygrid.org.uk/repository/myGrid/PaulFisher/.
- Published
- 2007
- Full Text
- View/download PDF
31. Method for measurement of peroxisomal very-long-chain fatty acid beta-oxidation in human skin fibroblasts using stable-isotope-labeled tetracosanoic acid.
- Author
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Kemp S, Valianpour F, Mooyer PA, Kulik W, and Wanders RJ
- Subjects
- Adrenoleukodystrophy metabolism, Deuterium, Feasibility Studies, Fibroblasts ultrastructure, Humans, Isotope Labeling, Oxidation-Reduction, Skin cytology, Spectrometry, Mass, Electrospray Ionization, Fatty Acids metabolism, Fibroblasts metabolism, Peroxisomes metabolism, Skin metabolism
- Published
- 2004
- Full Text
- View/download PDF
32. Pharmacokinetic and pharmacodynamic characteristics of a long-acting growth hormone (GH) preparation (nutropin depot) in GH-deficient children.
- Author
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Kemp SF, Fielder PJ, Attie KM, Blethen SL, Reiter EO, Ford KM, Marian M, Dao LN, Lee HJ, and Saenger P
- Subjects
- Child, Child, Preschool, Delayed-Action Preparations, Drug Administration Schedule, Female, Humans, Insulin-Like Growth Factor Binding Protein 3 blood, Insulin-Like Growth Factor I metabolism, Male, Metabolism, Inborn Errors blood, Metabolism, Inborn Errors drug therapy, Human Growth Hormone administration & dosage, Human Growth Hormone deficiency, Human Growth Hormone pharmacokinetics
- Abstract
Long-term GH replacement therapy is indicated for children with growth failure due to GH deficiency (GHD). We evaluated the feasibility of administering a long-acting GH preparation [Nutropin Depot (somatropin, rDNA origin) for injectable suspension] to prepubertal children with GHD by examining pharmacokinetic and pharmacodynamic response parameters after single or multiple doses. Data were collected from three studies involving 138 children treated with Nutropin Depot 0.75 mg/kg once per month, 0.75 mg/kg twice per month, or 1.5 mg/kg once per month. Twenty-two patients underwent intensive sampling to estimate mean peak serum GH concentrations (C(max)) and time to achieve C(max) for GH and IGF-I. Thereafter, weekly serum concentrations were measured and compared with baseline. C(max) and area under the curve were approximately proportional to the dose administered. Fractional area under the curve data indicate that at least 50% of GH exposure occurs during the first 2 d after administration. Serum GH levels remained above 1 microg/liter for 11-14 d. IGF-I levels remained above baseline for 16-20 d, but increases were not proportional to dose. After multiple doses over a 6-month period, peak and trough concentrations showed no progressive accumulation of GH, IGF-I, or IGF binding protein-3. Nutropin Depot administration once or twice per month provides serum levels of GH and IGF-I expected to promote growth, without accumulation of GH, IGF-I, or IGF binding protein-3, in children with GHD.
- Published
- 2004
- Full Text
- View/download PDF
33. Embodied practice: claiming the body's experience, agency, and knowledge for social work.
- Author
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Tangenberg KM and Kemp S
- Subjects
- Humans, Mind-Body Relations, Metaphysical, Social Work
- Abstract
Although social work practice typically is concerned with physical conditions and experiences such as poverty, addiction, and violence, relatively little attention has been given to the body in professional literature. Emphasizing both physical and sociocultural dimensions of the body, this article argues for an invigorated, more complex understanding of the body in social work theory, practice, and research. Drawing from scholarship in the humanities, social sciences, and social work, a framework involving three dimensions of the body is proposed for integration with accepted ecological practice models. The nature and implications of three primary dimensions of the body for multiple domains of social work practice are explored, citing examples from narratives of mothers living with HIV disease: (1) the experiencing body, focused on the physicality of daily life; (2) the body of power, focused on the physicality of oppression and marginality, typically based on race or ethnicity, socioeconomic status, gender, sexual orientation, age, disability, physical appearance, and illness; and (3) the client body, reflecting the bodily experiences of those identified as clients who participate in relationships with social workers.
- Published
- 2002
- Full Text
- View/download PDF
34. A multicenter study of the efficacy and safety of sustained release GH in the treatment of naive pediatric patients with GH deficiency.
- Author
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Reiter EO, Attie KM, Moshang T Jr, Silverman BL, Kemp SF, Neuwirth RB, Ford KM, and Saenger P
- Subjects
- Antibodies blood, Child, Child, Preschool, Female, Growth drug effects, Growth Hormone adverse effects, Growth Hormone immunology, Humans, Insulin-Like Growth Factor Binding Protein 3 blood, Insulin-Like Growth Factor I analysis, Male, Growth Hormone administration & dosage, Human Growth Hormone deficiency
- Abstract
Treatment of naive children with GH deficiency has relied upon long-term replacement therapy with daily injections of GH. The daily schedule may be inconvenient for patients and their caregivers, possibly promoting nonadherence with the treatment regimen or premature termination of treatment. We studied a new sustained release GH formulation, administered once or twice monthly, to determine its efficacy and safety in this population. Seventy-four prepubertal patients with documented GH deficiency were randomized to receive sustained release recombinant human GH at either 1.5 mg/kg once monthly or 0.75 mg/kg twice monthly by sc injection in a 6-month open-label study. Efficacy was determined by growth data from 69 patients completing 6 months and 56 patients completing 12 months in an extension study. Growth rates were significantly increased over baseline and were similar for the two dosage groups. The mean (+/-SD) annualized growth rate (pooled data) was 8.4 +/- 2.1 cm/yr at 6 months, and the growth rate was 7.8 +/- 1.8 at 12 months compared with 4.5 +/- 2.3 at baseline. Standardized height, bone age, and predicted adult height assessments demonstrated catch-up growth without excessive skeletal maturation. Injection site-related events (including pain, erythema, and nodules) were the most commonly reported adverse events; no serious adverse events related to treatment were reported. Laboratory studies documented no accumulation of trough GH or IGF-I levels during treatment, nor did glucose intolerance or persistent hyperinsulinism develop. Sustained release recombinant human GH is safe and effective for long-term GH replacement in children with GH deficiency. Patients achieved similar growth velocities when sustained release GH was given once or twice monthly. The enhanced convenience of this dosage form may result in greater long-term adherence to the treatment regimen.
- Published
- 2001
- Full Text
- View/download PDF
35. Resistance profile of the human immunodeficiency virus type 1 reverse transcriptase inhibitor abacavir (1592U89) after monotherapy and combination therapy. CNA2001 Investigative Group.
- Author
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Harrigan PR, Stone C, Griffin P, Nájera I, Bloor S, Kemp S, Tisdale M, and Larder B
- Subjects
- Acquired Immunodeficiency Syndrome virology, Codon, Dideoxynucleosides administration & dosage, Drug Resistance, Drug Therapy, Combination, HIV Reverse Transcriptase genetics, Humans, Mutation, Polymerase Chain Reaction, RNA, Viral analysis, Zidovudine administration & dosage, Zidovudine therapeutic use, Acquired Immunodeficiency Syndrome drug therapy, Anti-HIV Agents therapeutic use, Dideoxynucleosides therapeutic use, Reverse Transcriptase Inhibitors therapeutic use
- Abstract
Abacavir (1592U89) is a nucleoside inhibitor of human immunodeficiency virus (HIV) type 1 reverse transcriptase (RT). Resistance to abacavir was studied with abacavir alone and with abacavir in combination with other nucleoside analogues in cell culture, in virus isolates from zidovudine/lamivudine clinical trials, and in the first dose-escalating 12-week clinical trial (CNA2001) to evaluate abacavir clinical potency. Abacavir alone in vitro selected for mutations at HIV RT codons K65R, L74V, Y115F, and M184V. However, abacavir combined with zidovudine selected against virus with the M184V mutation. Abacavir therapy in vivo resulted in large decreases in HIV load (>1 log), even in 1 subject who had the M184V mutation at baseline. A total of 51% of subjects showed new mutations at any of codons K65R, L74V, and M184V after abacavir monotherapy, compared with 11% who received zidovudine/abacavir. Small changes (2- to 4-fold) in abacavir susceptibility were detected. On stopping therapy, reselection of the pretherapy sequence occurred within 4 weeks.
- Published
- 2000
- Full Text
- View/download PDF
36. Visual perception of motion, luminance and colour in a human hemianope.
- Author
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Morland AB, Jones SR, Finlay AL, Deyzac E, Lê S, and Kemp S
- Subjects
- Adult, Functional Laterality, Hemianopsia psychology, Humans, Light, Male, Photic Stimulation, Probability, Reference Values, Blindness, Cortical physiopathology, Color Perception, Hemianopsia physiopathology, Motion Perception, Visual Perception
- Abstract
Human patients rendered cortically blind by lesions to V1 can nevertheless discriminate between visual stimuli presented to their blind fields. Experimental evidence suggests that two response modes are involved. Patients are either unaware or aware of the visual stimuli, which they are able to discriminate. However, under both conditions patients insist that they do not see. We investigate the fundamental difference between percepts derived for the normal and affected hemifield in a human hemianope with visual stimuli of which he was aware. The psychophysical experiments we employed required the patient, GY, to make comparisons between stimuli presented in his affected and normal hemifields. The subject discriminated between, and was allowed to match, the stimuli. Our study reveals that the stimulus parameters of colour and motion can be discriminated and matched between the normal and blind hemifields, whereas brightness cannot. We provide evidence for associations between the percepts of colour and motion, but a dissociation between the percepts of brightness, derived from the normal and hemianopic fields. Our results are consistent with the proposal that the perception of different stimulus attributes is expressed in activity of functionally segregated visual areas of the brain. We also believe our results explain the patient's insistence that he does not see stimuli, but can discriminate between them with awareness.
- Published
- 1999
- Full Text
- View/download PDF
37. Dual resistance to zidovudine and lamivudine in patients treated with zidovudine-lamivudine combination therapy: association with therapy failure.
- Author
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Miller V, Phillips A, Rottmann C, Staszewski S, Pauwels R, Hertogs K, de Béthune MP, Kemp SD, Bloor S, Harrigan PR, and Larder BA
- Subjects
- Cross-Sectional Studies, Drug Resistance, Microbial genetics, Drug Therapy, Combination, Follow-Up Studies, HIV Infections physiopathology, HIV-1 genetics, Humans, Retrospective Studies, Treatment Failure, Anti-HIV Agents therapeutic use, Drug Resistance, Multiple genetics, HIV Infections drug therapy, HIV Infections virology, HIV-1 drug effects, Lamivudine therapeutic use, Reverse Transcriptase Inhibitors therapeutic use, Zidovudine therapeutic use
- Abstract
Human immunodeficiency virus type 1 (HIV-1) strains dually resistant to zidovudine and lamivudine (3TC) may arise during zidovudine-3TC combination therapy. The objective of this cross-sectional study (n = 43 patients) was to test the association between therapy response (clinical and immunologic) to zidovudine-3TC and the level of phenotypic zidovudine resistance and zidovudine resistance-associated genotype of 3TC-resistant isolates. Other variables included were baseline CD4+ cell count, baseline Centers for Disease Control and Prevention (CDC) classification, virus load, and time receiving zidovudine. Phenotypic resistance was assessed using a recombinant virus assay. Genotypic analysis was based on population sequencing of plasma HIV-1. In a univariate analysis using a logistic regression model, it was found that therapy response was significantly associated with phenotypic and genotypic zidovudine resistance, baseline CD4+ cell count, and virus load. After adjustment for all variables, phenotypic resistance to zidovudine remained the only significantly associated factor, independent of baseline CD4+ cell count, baseline CDC classification, and virus load.
- Published
- 1998
- Full Text
- View/download PDF
38. Odor perception phenotypes: multiple, specific hyperosmias to musks.
- Author
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Gilbert AN and Kemp SE
- Subjects
- Adult, Cluster Analysis, Female, Humans, Male, Phenotype, Odorants, Perfume, Sensation Disorders genetics, Smell genetics
- Abstract
Olfactory detection thresholds for 11 structurally diverse musk odorants and one non-musk odorant were obtained from 32 subjects. Hierarchical cluster analysis produced four groups of subjects. One group (n = 12) was uniformly sensitive to all musks; another (n = 16) was uniformly insensitive. Two groups of subjects contained otherwise insensitive individuals who were exceptionally sensitive to cyclopentadecanone and musk xylol (n = 2) and to delta9-hexadecenolactone and tonalid (n = 2) respectively. We propose that the latter two groups are odor perception phenotypes (MSHM1 and MSHM2) that consist of multiple, specific hyperosmias to musk odorants.
- Published
- 1996
- Full Text
- View/download PDF
39. Single and multiple dose pharmacokinetics of methionyl growth hormone in children with idiopathic growth hormone deficiency.
- Author
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Kearns GL, Kemp SF, and Frindik JP
- Subjects
- Adolescent, Child, Dose-Response Relationship, Drug, Growth Disorders etiology, Growth Disorders metabolism, Growth Hormone administration & dosage, Growth Hormone deficiency, Growth Hormone pharmacokinetics, Growth Hormone therapeutic use, Half-Life, Human Growth Hormone, Humans, Male, Growth Disorders drug therapy, Growth Hormone analogs & derivatives
- Abstract
The pharmacokinetics (PK) of methionyl GH (metGH) were characterized in 20 newly diagnosed GH-deficient children (19 males; 12.9 +/- 3.3 yr old; initial height, 138.8 +/- 16.2 cm; weight, 32.1 +/- 13.1 kg) after the first dose (FD) of metGH and again after 4-5 weeks of multiple dosing (MD). All subjects received a total metGH dose of 0.3 mg/kg.week by sc administration, but were randomized to receive the drug daily (D; n = 12; dose, 0.043 mg/kg) or three times per week (TIW; n = 8; dose, 0.1 mg/kg). After drug administration, repeated blood samples (n = 14) were obtained over a 10-h period. Concentrations of metGH from each sample were determined using a monoclonal antibody radiometric assay (range of linearity, 0.5-40.0 ng/ml; coefficient of variation, less than 4%). Plasma concentration vs. time data were curve fit using a nonlinear weighted least squares algorithm which permitted calculation of the following PK parameters (mean +/- SEM; FD vs. MD group): elimination rate constant (0.23 +/- 0.04 vs. 0.25 +/- 0.04 h-1), absorption rate constant (0.43 +/- 0.05 vs. 0.48 +/- 0.04 h-1), elimination half-life (t1/2; 3.01 vs. 2.77 h), total plasma clearance (CL/F; 0.32 +/- 0.02 vs. 0.54 +/- 0.09 L/h.kg), and apparent volume of distribution (VDss/F; 2.2 +/- 0.14 vs. 3.15 +/- 0.28 L/kg). Both the CL/F and VDss/F of metGH were significantly greater when data from the entire study population were compared on the basis of FD vs. MD administration. With the exception of a larger VDss/F in subjects who received daily (3.6 +/- 0.4 L/kg) vs. TIW metGH (2.4 +/- 0.2 L/kg), no significant differences were found for the PK parameters between the D and TIW dosing groups. In all subjects, absorption of metGH was slow, with an average time to reach maximum concentration (Tmax) of 4.4 h and an absorption t1/2 that ranged from 1.4-1.8 h. Proportionality was also found between the dose and the area under the plasma concentration vs. time curve, suggesting dose-independent PK of metGH. Our data demonstrate that the PK of metGH after sc administration to children are markedly different from those previously reported in adults and, also, do not vary as a consequence of dosing schedule (i.e. D vs. TIW). The apparent increase in CL/F and VDss/F for met GH with multiple dosing may reflect concentration-dependent changes in plasma binding of the drug or, alternatively, represent the effect of increased body mass on the pharmacokinetics of GH.
- Published
- 1991
- Full Text
- View/download PDF
40. Constancy of somatomedin response to growth hormone treatment of hypopituitary dwarfism, and lack of correlation with growth rate.
- Author
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Rosenfeld RG, Kemp SF, and Hintz RL
- Subjects
- Adolescent, Adult, Child, Child, Preschool, Dwarfism, Pituitary blood, Growth Hormone deficiency, Humans, Radioimmunoassay, Dwarfism, Pituitary drug therapy, Growth Hormone therapeutic use, Insulin blood, Peptides blood, Somatomedins blood
- Published
- 1981
- Full Text
- View/download PDF
41. Plasma somatomedin-binding proteins in hypopituitarism: changes during growth hormone therapy.
- Author
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Hintz RL, Liu F, Rosenfeld RG, and Kemp SF
- Subjects
- Child, Growth Hormone deficiency, Humans, Hypopituitarism drug therapy, Insulin blood, Insulin-Like Growth Factor Binding Proteins, Insulin-Like Growth Factor I, Peptides blood, Somatomedins blood, Carrier Proteins metabolism, Growth Hormone therapeutic use, Hypopituitarism blood, Somatomedins metabolism
- Abstract
The somatomedin (SM) peptides are carried in plasma complexed to specific SM-binding proteins (SMBPs). In addition to the SMBP in the complex, there is an unsaturated SMBP in plasma in which the SMBP is not occupied by SMs. We have compared levels of unsaturated SMBP in 7 normal adults to those in 21 children with GH deficiency before and during treatment with hGH (0.1 U/kg.day) for 4 days. In addition, the SM-C/insulin-like growth factor I (IGF-I) content of each plasma was measured by RIA. There was a significant (P less than 0.01) difference in unsaturated SMBP levels between normal controls (17.8 +/- 0.8% bound/20 microliters) and untreated hypopituitary patients (27.8 +/- 2.2% bound/20 microliters). Thus, a lower SM-C/IGF-I content was associated with a higher unsaturated SMBP level. Furthermore, there was a significant negative correlation between SM-C/IGF-I content and unsaturated SMBP in untreated hypopituitary patients (r = 0.73; P less than 0.0001). Treatment with hGH normalized the mean unsaturated SMBP level in hypopituitary patients within 2 days. Full displacement curves and Scatchard analysis showed that the increased unsaturated SMBP level in hypopituitary plasma was entirely due to an increased affinity (8.4 X 0.9 X 10(-10) M) compared to normal (2.3 X 0.2 X 10(-9) M). A higher affinity form of unsaturated SMBP is uniquely present in hypopituitarism and disappears with hGH treatment. The measurement of this unsaturated SMBP mirrors the SM peptide content.
- Published
- 1981
- Full Text
- View/download PDF
42. In vivo modulation of somatomedin receptor sites: effects of growth hormone treatment of hypopituitary children.
- Author
-
Rosenfeld RG, Kemp SF, Gaspich S, and Hintz RL
- Subjects
- Child, Child, Preschool, Dwarfism, Pituitary drug therapy, Female, Humans, Kinetics, Male, Monocytes metabolism, Receptors, Cell Surface drug effects, Receptors, Somatomedin, Dwarfism, Pituitary metabolism, Growth Hormone therapeutic use, Receptors, Cell Surface metabolism
- Abstract
We have previously demonstrated that somatomedin (SM) can induce the loss of specific SMC receptors on cultured IM-9 lymphocytes in a time- and concentration-dependent manner. To investigate the acute regulation of SM binding under in vivo conditions, we have evaluated SM receptors on circulating mononuclear cells obtained from 12 hypopituitary dwarfs before and after 4 days of human GH administration (0.1 U/kg . day). Plasma SM levels, measured by radioreceptor assay, rose from 0.37 +/- 0.08 U/ml (mean +/- SEM) to 1.00 +/- 0.10 (P less than 0.001). Concomitantly, specific binding of [125I]SMC to 50 x 10(6) mononuclear cells/ml fell from 13.61 +/- 0.97% to 10.40 +/- 0.85% (P less than 0.02). The decrease in specific binding was predominantly secondary to a reduced number of SMC receptor sites per cell, with no alteration in receptor affinity. Overall, a significant inverse correlation was observed between plasma SM levels and mononuclear cellular binding of [125I]SMC (P less than 0.001). The data demonstrate that treatment of hypopituitary dwarfs with conventional therapeutic doses of human GH results in significant acute increases in plasma SM levels in the majority of subjects, with a reciprocal decline in the specific binding of [125I]SMC. We conclude that SM, like insulin, is capable of regulating homologous receptor concentrations under both in vitro and in vivo conditions.
- Published
- 1981
- Full Text
- View/download PDF
43. Structural characterization of HIV reverse transcriptase: a target for the design of specific virus inhibitors.
- Author
-
Tisdale M, Larder BA, Lowe DM, Stammers DK, Purifoy DJ, Ertl P, Bradley C, Kemp S, Darby GK, and Powell KL
- Subjects
- Animals, Antibodies, Monoclonal, Cloning, Molecular, Epitopes analysis, HIV genetics, Humans, Mice, Peptide Mapping, RNA-Directed DNA Polymerase biosynthesis, RNA-Directed DNA Polymerase isolation & purification, Recombinant Proteins biosynthesis, Recombinant Proteins isolation & purification, Antiviral Agents pharmacology, Drug Design, HIV enzymology, Reverse Transcriptase Inhibitors
- Abstract
The reverse transcriptase (RT) of HIV is an important target for chemotherapy as demonstrated by the effective treatment of AIDS patients with zidovudine, a potent inhibitor of RT. Structural studies of HIV RT were therefore undertaken with a view to designing more effective inhibitors. To obtain sufficient quantities of enzyme for these studies the reverse transcriptase gene of HIV was cloned into a high level expression plasmid yielding reverse transcriptase at a level of 10% of the total Escherichia coli proteins. Monoclonal antibodies to RT were raised in mice and have been used to purify the enzyme by immunoaffinity chromatography. Crystallization of the enzyme has been achieved and studies are underway to determine its three-dimensional structure. In addition, carboxy-terminal truncated mutants were prepared by inserting stop codons into the gene at appropriate sites. The proteins expressed were analysed for RT and RNase H activity and used for mapping RT epitopes. This, together with previous data on site-directed mutagenesis of conserved regions of HIV RT has helped to map some of the structural and functional regions of the enzyme.
- Published
- 1989
- Full Text
- View/download PDF
44. Growth hormone and somatomedin in insulin-dependent diabetes mellitus.
- Author
-
Horner JM, Kemp SF, and Hintz RL
- Subjects
- Adolescent, Blood Glucose metabolism, Child, Circadian Rhythm, Female, Glycated Hemoglobin metabolism, Humans, Male, Diabetes Mellitus, Type 1 blood, Growth Hormone blood, Somatomedins blood
- Abstract
In order to study the interrelationship of GH, somatomedin (SM), and growth in insulin-dependent diabetes mellitus (IDDM), concentrations of serum glucose, serum GH, and plasma SM were determined at 2-h intervals for 48 h in 19 ambulatory children with IDDM of at least 2-yr duration (mean duration, 6 yr) and in 9 normal age-matched controls. Serum glucose was significantly elevated (P less than 0.001) in subjects with IDDM compared to controls [287 +/- 15 mg/dl vs. 99 +/- 2 mg/dl (mean +/- SEM)] as was the hemoglobin A1C (11.0 +/- 0.40% vs. 4.59 +/- 0.08%) and the serum GH (8.4 +/- 0.4 ng/ml vs. 5.6 +/- 0.6 ng/ml; P less than 0.002). Despite evidence of inadequate diabetes control and elevated GH levels, the subjects with IDDM had normal SM levels (1.82 +/- 0.14 U/ml) compared to their age-matched controls (mean, 1.66 +/- 0.19 U/ml) and normal growth. Furthermore, SM levels did not show any significant diurnal variation in either group. There was no significant correlation in either group between the mean plasma SM concentrations and the mean serum GH or mean serum glucose concentration of each subject. These findings of normal SM levels and elevated GH levels in these children with normal stature and IDDM suggest a partial block in GH action.
- Published
- 1981
- Full Text
- View/download PDF
45. Acute somatomedin response to growth hormone: radioreceptor assay versus radioimmunoassay.
- Author
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Kemp SF, Rosenfeld RG, Liu F, Gaspich S, and Hintz RL
- Subjects
- Adolescent, Adult, Child, Child, Preschool, Growth Hormone deficiency, Humans, Hypopituitarism blood, Hypopituitarism drug therapy, Iodine Radioisotopes, Kinetics, Male, Radioimmunoassay, Radioligand Assay, Reference Values, Growth Hormone therapeutic use, Somatomedins blood
- Abstract
The acute somatomedin (SM) response to GH therapy has been examined in 21 GH-deficient children using a placental membrane radioreceptor assay (RRA) which measures a variety of SMs and a RIA specific for SM-C and insulin-like growth factor I (IGF-I). Plasma for determination of SM peptide content was obtained before initiation of therapy and 13 h after each of four daily injections of GH (0.1 U/kg). An additional SM determination was performed after 6 weeks of GH therapy (0.1 U/kg, three times per week) in seven of the subjects. RRA and RIA SM determinations were performed on the same acid-chromatographed sample and were compared to an acid-chromatographed pooled plasma standard. The 4 days of GH therapy resulted in an increase in SM levels from 0.39 +/- 0.24 to 1.18 +/- 0.62 (+/- SD) U/ml, determined by RIA. A single injection of GH resulted in a significant rise in plasma SM levels, measured by either RRA or RIA (P less than 0.001). Subjects who responded poorly to two injections of GH also had low SM levels after 4 days and even after 6 weeks of GH therapy. The RRA resulted in consistently higher value than the RIA. This difference was even greater when results were compared to a pure IGF-I/SM-C standard. The SM peptide contents determined by RRA and RIA were strongly correlated, not only for the group, but also among the determinations for each individual subject. However, the consistently higher values observed when the SM peptide content was measured by RRA compared to that measured by RIA and the variability in the RRA to RIA ratio among individual subjects suggest that the IGF-I/SM-C RIA measures only one of a number of GH-dependent SM peptides.
- Published
- 1981
- Full Text
- View/download PDF
46. The action of somatomedin on glycosaminoglycan synthesis in cultured chick chondrocytes.
- Author
-
Kemp SF and Hintz RL
- Subjects
- Animals, Cartilage drug effects, Cells, Cultured, Chick Embryo, Cycloheximide pharmacology, Kinetics, Protein Biosynthesis, Cartilage metabolism, Glycosaminoglycans biosynthesis, Somatomedins pharmacology
- Abstract
A basic somatomedin preparation results in a 2-fold stimulation of incorporation of both [3H]leucine into protein and 35SO4 into glycosaminoglycans by cultured chick sternal chondrocytes. The stimulation is seen in the presence of 20 mM 4-methylumbelliferyl-beta-D-xyloside alone but is not observable in the presence of both xyloside and cycloheximide, indicating that the stimulation by somatomedin is dependent on protein synthesis. Somatomedin stimulates incorporation of leucine into glycosaminoglycans to the same extent to which it stimulates incorporation of sulfate into glycosaminoglycans, suggesting involvement of core protein synthesis. In the presence of the xyloside, however, there is stimulation of synthesis of glycosaminoglycan chains initiated on the xyloside, with a shift in molecular weight distribution to larger molecular weights. Thus, when core protein is not rate limiting, a more general stimulatory effect of somatomedin is observed.
- Published
- 1980
- Full Text
- View/download PDF
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