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Calcareous termite mounds in South Africa are ancient carbon reservoirs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 926:171760. [PMID: 38537830 DOI: 10.1016/j.scitotenv.2024.171760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/03/2024] [Accepted: 03/14/2024] [Indexed: 04/05/2024]
Abstract
Ecosystems that offer carbon sequestration by leaching bicarbonate to groundwater are valuable natural capital. One region that may offer this service is the west coast of South Africa. Over 20 % is covered by soil mounds ("heuweltjies") up to 40 m diameter, 2 m high, inhabited by the southern harvester termite Microhodotermes viator and enriched in soil organic and inorganic carbon and soluble minerals. We aimed to generate radiogenic and stable isotope data for soils and groundwater in a region where these data are absent, to 1) verify the atmosphere-soil-groundwater link, and 2) resolve the timing and pattern of calcite dissolution and water infiltration in the landscape. Results show that soil and groundwater sulfate have the same marine aerosol source. Episodic calcite dissolution in mound centers, which increased during periods of global cooling, has been set against background input of marine aerosols since before the Last Glacial according to radiocarbon (14C) ages. Our data push back soil organic carbon 14C ages of inhabited termite mounds to 13-19 ka (kiloannum, thousand years before present), nest carbonate 14C ages to 33 ka, and mound soil carbonate 14C ages to 34 ka, making these the oldest active termite features ever dated. These ages are consistent with soil organic carbon and carbonate 14C ages of regional, non-mound, coastal petrocalcic horizons formed by accumulation of carbonate leached from their overlying aeolian dune fields. Harvesting activities of termites inject younger organic material around nests >1 m deep, leading to continuous renewal of important soil carbon reservoirs at depth. Termite bioturbation increases the system's ability to dissolve carbonate. The central, bioturbated part of the mounds have greater infiltration depths and greater calcite dissolution, whereas surrounding soils experienced more surface runoff. Calcareous termite mounds offer a mechanism to sequester CO2 through dissolution and leaching of soil carbonate-bicarbonate to groundwater.
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Long-term Effectiveness of Adjuvant Treatment With Catechol-O-Methyltransferase or Monoamine Oxidase B Inhibitors Compared With Dopamine Agonists Among Patients With Parkinson Disease Uncontrolled by Levodopa Therapy: The PD MED Randomized Clinical Trial. JAMA Neurol 2021; 79:131-140. [PMID: 34962574 PMCID: PMC8715387 DOI: 10.1001/jamaneurol.2021.4736] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Question Is adding a dopamine reuptake inhibitor (DRI), either a monoamine oxidase type B (MAO-B) inhibitor or a catechol-O-methyltransferase (COMT) inhibitor, to levodopa therapy more effective than adding a dopamine agonist and, if a DRI is more effective, which DRI class (MAO-B or COMT) is preferable for improving patient-rated quality of life among those with motor complications of Parkinson disease (PD) that are uncontrolled by levodopa therapy? Findings In this randomized clinical trial involving 500 people with PD, no statistically significant difference was found in Parkinson’s Disease Questionnaire mobility scores between adjuvant therapy with dopamine agonists vs DRIs; however, scores were a mean of 4.2 points better with MAO-B inhibitors compared with COMT inhibitors. Meaning In this study, patient-rated quality of life was worse with the addition of COMT inhibitors compared with MAO-B inhibitors or dopamine agonists as adjuvant treatment for people with PD uncontrolled by levodopa therapy. Importance Many people with Parkinson disease (PD) develop motor complications that are uncontrolled by levodopa dose adjustment. Among these patients, it is uncertain which drug class is more effective as adjuvant therapy. Objective To compare the long-term effects on patient-rated quality of life of adding a dopamine agonist vs a dopamine reuptake inhibitor (DRI), either a monoamine oxidase type B (MAO-B) inhibitor or a catechol-O-methyltransferase (COMT) inhibitor, to levodopa therapy for the treatment of patients with motor complications of PD. Design, Setting, and Participants This pragmatic semifactorial (2 × 1) randomized clinical trial recruited from 64 neurology and geriatric clinics (62 in the United Kingdom, 1 in the Czech Republic, and 1 in Russia) between February 23, 2001, and December 15, 2009. A total of 500 patients with idiopathic PD who developed uncontrolled motor complications and did not have dementia were randomly assigned on a 1:1:1 basis using a computerized minimization program. Data were analyzed between 2017 and 2020. Interventions Open-label dopamine agonist, MAO-B inhibitor, or COMT inhibitor. Main Outcomes and Measures Primary outcomes were scores on the 39-item Parkinson’s Disease Questionnaire (PDQ-39) mobility domain and cost-effectiveness. Outcomes were assessed before study entry, at 6 and 12 months after randomization, and annually thereafter. Repeated-measures and log rank analyses were used in an intention-to-treat approach. Results Among 500 participants, the mean (SD) age was 73.0 (8.2) years; 314 participants (62.8%) were men. Over a median of 4.5 years (range, 0-13.3 years) of follow-up, the participants in the dopamine agonist group had a mean PDQ-39 mobility score that was 2.4 points (95% CI, −1.3 to 6.0 points) better than that of the combined MAO-B and COMT groups; however, this difference was not significant (P=.20). With regard to DRIs, participants in the MAO-B group had mean PDQ-39 mobility scores that were 4.2 points (95% CI, 0.4-7.9 points; P=.03) better than those of the COMT group and EuroQol 5-dimension 3-level (EQ-5D-3L) utility scores that were 0.05 points (95% CI, 0.003-0.09 points; P=.04) better than the COMT group. Nonsignificant improvements were found in the PDQ-39 summary index (mean difference, 2.2 points; 95% CI, −0.2 to 4.5 points; P=.07) along with nonsignificant reductions in dementia (rate ratio [RR], 0.70; 95% CI, 0.47-1.03; P = .07) and mortality (RR, 0.76; 95% CI, 0.56-1.03; P=.07). When dopamine agonists were compared with MAO-B inhibitors only, the outcomes were similar. Conclusions and Relevance In this study, patient-rated quality of life was inferior when COMT inhibitors were used as adjuvant treatment compared with MAO-B inhibitors or dopamine agonists among people with PD who experienced motor complications that were uncontrolled by levodopa therapy. The MAO-B inhibitors produced equivalent disease control, suggesting that these agents may be underused as adjuvant therapy. Trial Registration isrctn.org Identifier: ISRCTN69812316; EU Clinical Trials Register Identifier: 2005-001813-16
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Saline groundwater in the Buffels River catchment, Namaqualand, South Africa: A new look at an old problem. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 762:143140. [PMID: 33131834 DOI: 10.1016/j.scitotenv.2020.143140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/28/2020] [Accepted: 10/12/2020] [Indexed: 06/11/2023]
Abstract
Namaqualand, South Africa, is a global biodiversity hotspot but local populations are affected by challenging economic conditions largely because of poor access to water. In this study groundwater types are characterised and sources of salts and salinisation processes are identified using hydrochemistry and δ18O, δ2H and 87Sr/86Sr data. Analysis of δ18O and δ2H data suggests that evaporation does not play a major role in salinisation of the groundwater. However, major ion chemistry and 87Sr/86Sr ratios indicate that salts present in the groundwater are linked to dry deposition of marine aerosols and ion-exchange reactions in soils in the alluvial aquifer systems. The hydrochemical variability of the groundwater in the basement aquifer system suggests that there are strong local controls linked to weathering processes in individual basement rock types. The region is also notable for the high density of heuweltjies, biophysical features associated with increased nutrient levels, associated with termite activity. Electromagnetic scanning as well as measurement of water-soluble soil electrical conductivity values on and off heuweltjies, show that heuweltjies are saline with salinity increasing with depth. The level of groundwater salinity correlates with the level of heuweltjie salinity. Precipitation records from the last 150 years provide support for the hypothesis that accumulated salts, and in particular, heuweltjie salts are flushed into the groundwater system during sporadic large volume precipitation events. Thus, heuweltjies and hence termite activity, could potentially represent a previously unrecognized contributor to groundwater salinisation across Namaqualand and in other parts of the world.
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A multicentre, randomised controlled trial to compare the clinical and cost-effectiveness of Lee Silverman Voice Treatment versus standard NHS Speech and Language Therapy versus control in Parkinson's disease: a study protocol for a randomised controlled trial. Trials 2020; 21:436. [PMID: 32460885 PMCID: PMC7251680 DOI: 10.1186/s13063-020-04354-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/27/2020] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Parkinson's disease (PD) affects approximately 145,519 people in the UK. Speech impairments are common with a reported prevalence of 68%, which increase physical and mental demands during conversation, reliance on family and/or carers, and the likelihood of social withdrawal reducing quality of life. In the UK, two approaches to Speech and Language Therapy (SLT) intervention are commonly available: National Health Service (NHS) SLT or Lee Silverman Voice Treatment (LSVT LOUD®). NHS SLT is tailored to the individuals' needs per local practice typically consisting of six to eight weekly sessions; LSVT LOUD® comprises 16 sessions of individual treatment with home-based practice over 4 weeks. The evidence-base for their effectiveness is inconclusive. METHODS/DESIGN PD COMM is a phase III, multicentre, three-arm, unblinded, randomised controlled trial. Five hundred and forty-six people with idiopathic PD, reporting speech or voice problems will be enrolled. We will exclude those with a diagnosis of dementia, laryngeal pathology or those who have received SLT for speech problems in the previous 2 years. Following informed consent and completion of baseline assessments, participants will be randomised in a 1:1:1 ratio to no-intervention control, NHS SLT or LSVT LOUD® via a central computer-generated programme, using a minimisation procedure with a random element, to ensure allocation concealment. Participants randomised to the intervention groups will start treatment within 4 (NHS SLT) or 7 (LSVT LOUD®) weeks of randomisation. PRIMARY OUTCOME Voice Handicap Index (VHI) total score at 3 months. Secondary outcomes include: VHI subscales, Parkinson's Disease Questionnaire-39; Questionnaire on Acquired Speech Disorders; EuroQol-5D-5 L; ICECAP-O; resource utilisation; adverse events and carer quality of life. Mixed-methods process and health economic evaluations will take place alongside the trial. Assessments will be completed before randomisation and at 3, 6 and 12 months after randomisation. The trial started in December 2015 and will run for 77 months. Recruitment will take place in approximately 42 sites around the UK. DISCUSSION The trial will test the hypothesis that SLT is effective for the treatment of speech or voice problems in people with PD compared to no SLT. It will further test whether NHS SLT or LSVT LOUD® provide greater benefit and determine the cost-effectiveness of both interventions. TRIAL REGISTRATION International Standard Randomised Controlled Trials Number (ISRCTN) Registry, ID: 12421382. Registered on 18 April 2016.
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Annual Dynamics of Winery Wastewater Volumes and Quality and the Impact of Disposal on Poorly Drained Duplex Soils. S AFR J ENOL VITIC 2018. [DOI: 10.21548/39-2-3208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Two cases of anti-programmed cell death 1-associated bullous pemphigoid-like disease and eruptive keratoacanthomas featuring combined histopathology. J Eur Acad Dermatol Venereol 2017; 31:e378-e380. [DOI: 10.1111/jdv.14179] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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A Delphi Survey of Best Practice Occupational Therapy for Parkinson's Disease in the United Kingdom. Br J Occup Ther 2016. [DOI: 10.1177/030802260306600603] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study was designed to determine the character of best occupational therapy practice for Parkinson's disease in the United Kingdom. Two hundred and forty-two occupational therapists treating people with Parkinson's disease were sent a Delphi survey containing statements about best practice and asked to indicate their level of agreement with each statement. The second survey contained the same list of statements, with group levels of agreement from the first round for each statement. The respondents re-rated their answers and gave their opinion on the efficacy of various interventions. One hundred and fifty occupational therapists (62%) completed both rounds. Ninety-nine per cent of the respondents agreed that Parkinson's disease required lifelong provision of occupational therapy, within multidisciplinary teams, and that the social and psychological aspects of the disease were as important as the physical ones. The occupational therapists had confidence in many techniques for achieving physical, social and psychological goals. However, 40% of the respondents could not rate the efficacy of social and psychological techniques owing to a lack of knowledge. There was a high level of consensus nationally on the character of best practice occupational therapy for Parkinson's disease. The survey highlighted a need for more postgraduate training, especially in psychological techniques.
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A Survey of Current Occupational Therapy Practice for Parkinson's Disease in the United Kingdom. Br J Occup Ther 2016. [DOI: 10.1177/030802260306600503] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Little is known about the current character of occupational therapy practice for Parkinson's disease in the United Kingdom. The study aimed to document this in order to inform plans for a future multicentre randomised controlled trial. Two hundred and forty-two occupational therapists that treated people with Parkinson's disease were sent a questionnaire regarding demographics, service organisation and therapy content. One hundred and sixty-nine occupational therapists (70%) responded. They had worked with people with Parkinson's disease for a median of 6 years and personally treated a median of 15 people with Parkinson's disease annually. Most (86%) were at senior grade or above; 87% worked in the National Health Service and 12% in social services. Forty per cent worked in specialist Parkinson's disease clinics. Most (79%) felt that they needed more specialist postgraduate training. Occupational therapists are employed in both health and social care settings. The character of the occupational therapy is often determined by the location in which it is provided. Current occupational therapy appears to focus on functional activities rather than on the wider social and psychological aspects of occupation. Many occupational therapists felt that they needed more specialist postgraduate training to treat people with Parkinson's disease effectively.
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Treatment Reasons, Resource use and Costs of Hospitalisations in People with Parkinson's: Results from a Large Rct. VALUE IN HEALTH : THE JOURNAL OF THE INTERNATIONAL SOCIETY FOR PHARMACOECONOMICS AND OUTCOMES RESEARCH 2014; 17:A809. [PMID: 27203055 DOI: 10.1016/j.jval.2014.08.541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
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Reasons for Parkinson's disease admissions in a large inner city hospital. Parkinsonism Relat Disord 2013; 20:237-8. [PMID: 24269282 DOI: 10.1016/j.parkreldis.2013.10.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 09/30/2013] [Accepted: 10/09/2013] [Indexed: 11/24/2022]
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074 Rating papilloedema: an evaluation of the Frisen classification in idiopathic intracranial hypertension. J Neurol Psychiatry 2012. [DOI: 10.1136/jnnp-2011-301993.116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Abstract
Neurological conditions comprise a significant proportion of patient admissions to hospital but, in the majority of cases, are admitted under the care of non-neurological physicians. As a consequence, neurological ward consultations are commonly requested by the admitting medical teams to review diagnoses and management plans. The outcomes of neurological ward consultations were examined and the time required for the referral process recorded by performing a detailed prospective three-month audit of inpatient referrals to the neurology service. The consultations of 120 patients were recorded, categorised and analysed. These consultations were beneficial in the vast majority of cases, with a clear impact on patient diagnoses or management plans. The consultation process was time consuming, however, both in respect of the initial review, but also with follow-up visits. This audit highlights the importance of neurological input in the diagnosis and management of hospital inpatients. The time taken for this process should be resourced appropriately.
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POH07 Use of complementary and alternative medicine by patients attending a UK headache clinic. Journal of Neurology, Neurosurgery and Psychiatry 2010. [DOI: 10.1136/jnnp.2010.226340.141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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The use of complementary and alternative medicine by patients attending a UK headache clinic. Complement Ther Med 2010; 18:128-34. [PMID: 20688258 DOI: 10.1016/j.ctim.2010.05.035] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 03/01/2010] [Accepted: 05/22/2010] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVES This study was undertaken in order to determine the extent of the use of CAM in a UK headache clinic. DESIGN Ninety-two patients attending a headache clinic were given a questionnaire containing questions regarding their headaches and their use of CAM for headaches. SETTING Outpatient headache clinic, Birmingham, UK. Main outcome measures. The use of complementary and alternative therapies and predictive factors. RESULTS 32% of respondents had used a median of 3 different CAM therapies for their headache. The commonest source of recommendation of CAM use was a friend or relative (72%) and the commonest reason given for using CAM was as a last resort after trying all conventional therapies offered (48%). CAM therapies were perceived as beneficial by 60% of CAM users and no users perceived the CAM therapy to worsen their headache. 42% of CAM users had not disclosed it to their doctor or nurse, 80% of these giving the reason that the doctor or nurse never asked, rather than fear of discouragement or lack of understanding. Individuals who were in employment were more likely to have used CAM than those who were not. Binary logistic regression revealed Headache Impact Test (HIT-6) score to be a significant predictor of CAM use (Odds Ratio=1.38 [95% CI 1.05-1.81]). CONCLUSIONS As a matter of desperation, headache clinic patients try CAM therapies. Health care professionals involved in the management of headache should be aware of this. There is a need for evaluation of the benefits and safety of CAM therapies for headache.
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Pilot randomised controlled trial of occupational therapy to optimise independence in Parkinson's disease: the PD OT trial. J Neurol Neurosurg Psychiatry 2009; 80:976-8. [PMID: 18339727 DOI: 10.1136/jnnp.2007.138586] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To perform a pilot trial of occupational therapy (OT) to optimise functional independence in Parkinson disease (PD) to assess accrual/withdrawal rates, acceptability, outcome measures, and inform sample-size calculation. METHOD Non-demented patients with idiopathic PD and difficulties with activities of daily living (ADL) were recruited provided they had not received OT in the last 2 years and/or physiotherapy in the last year. Patients were randomised to immediate OT or OT after completion of the trial. Patients randomised to OT were assessed at home by an experienced therapist and then received six home treatment sessions over 2 months. Interventions were targeted at functional independence and mobility goals. Outcome measures were: Nottingham Extended Activity of Daily Living Scale, Rivermead Mobility Index, Unified Parkinson's Disease Rating Scale ADL scale, Parkinson's Disease Questionnaire 39, EuroQol-EQ-5D, Hospital Anxiety and Depression Scale, and health economics analysis. RESULTS 39 patients (25 male; mean age 73 years) were recruited from four centres over 16 months. The mean difference in NEADL at 8 months was 3.5 (95% CI -3.2 to 10.2). The mean difference in PDQ-39 Summary Score was 3.8 (95% CI -4.94 to 12.6). There were strong correlations between the PDQ-39 and other outcomes. The intervention was acceptable to patients, with a low withdrawal rate and good questionnaire completion. CONCLUSION Randomisation to a trial of OT in PD is feasible. NEADL and PDQ-39 are relevant outcomes and provided data to inform sample size for an adequately powered randomised trial for which there is pressing need.
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Epidemiology of joint disorders in Parkinson's disease and their impact on health status. J Clin Neurosci 2009; 16:1382-3. [PMID: 19576783 DOI: 10.1016/j.jocn.2009.01.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Revised: 12/29/2008] [Accepted: 01/21/2009] [Indexed: 10/20/2022]
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Elevated cerebrospinal fluid (CSF) leptin in idiopathic intracranial hypertension (IIH): evidence for hypothalamic leptin resistance? Clin Endocrinol (Oxf) 2009; 70:863-9. [PMID: 18771566 DOI: 10.1111/j.1365-2265.2008.03401.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE The aetiology of idiopathic intracranial hypertension (IIH) is not known, but its association with obesity is well-recognized. Recent studies have linked obesity with abnormalities in circulating inflammatory and adiposity related cytokines. The aim of this study was to characterize adipokine and inflammatory cytokine profiles in IIH. DESIGN Paired serum and cerebrospinal fluid (CSF) specimens were collected from 26 patients with IIH and compared to 62 control subjects. Samples were analysed for leptin, resistin, adiponectin, insulin, IL-1beta, IL-6, IL-8 (CXCL8), TNFalpha, MCP-1 (CCL2), hepatocyte growth factor, nerve growth factor and PAI-1 using multiplex bead immunoassays. RESULTS CSF leptin was significantly higher in patients with IIH (P = 0.001) compared to controls after correction for age, gender and body mass index (BMI). In the control population, BMI correlated with serum leptin (r = 0.34; P = 0.007) and CSF leptin (r = 0.51; P < 0.0001), but this was not the case for the IIH population. Profiles of other inflammatory cytokines and adipokines did not differ between IIH patients and controls once anthropometric factors had been accounted for. CONCLUSIONS IIH was characterized by significantly elevated CSF leptin levels which did not correlate with BMI. We suggest that CSF leptin may be important in the pathophysiology of IIH and that obesity in IIH may occur as a result of hypothalamic leptin resistance.
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Identification of a region in the TASK3 two pore domain potassium channel that is critical for its blockade by methanandamide. Br J Pharmacol 2007; 152:778-86. [PMID: 17828294 PMCID: PMC2190017 DOI: 10.1038/sj.bjp.0707436] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Revised: 07/20/2007] [Accepted: 07/25/2007] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE The TASK subfamily of two pore domain potassium channels (K2P) encodes for leak K currents, contributing to the resting membrane potential of many neurons and regulating their excitability. TASK1 and TASK3 channels are regulated by a number of pharmacological and physiological mediators including cannabinoids such as methanandamide. In this study, we investigate how methanandamide blocks these channels. EXPERIMENTAL APPROACH Currents through wild type and mutated TASK1 and TASK3 channels expressed in modified HEK-293 cells were measured using whole-cell electrophysiological recordings in the presence and absence of methanandamide. KEY RESULTS Methanandamide (3 microM) produced substantial block of hTASK1, hTASK3 and mTASK3 channels but was most potent at blocking hTASK3 channels. Block of these channels was irreversible unless cells were washed with buffer containing bovine serum albumin. Mutation of the distal six amino acids of TASK1 did not alter methanandamide inhibition, whilst C terminal truncation of TASK3 channels caused a small but significant reduction of inhibition. However, deletion of six amino acids (VLRFLT) at the interface between the final transmembrane domain and cytoplasmic C terminus of TASK3 channels gave functional currents that were no longer inhibited by methanandamide or by activation of GPCRs. CONCLUSIONS AND IMPLICATIONS Methanandamide potently blocked TASK3 and TASK1 channels and both methanandamide and G protein-mediated inhibition converged on the same intracellular gating pathway. Physiologically, methanandamide block of TASK1 and TASK3 channels may underpin a number of CNS effects of cannabinoids that are not mediated through activation of CB1 or CB2 receptors.
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MESH Headings
- Amino Acids/genetics
- Animals
- Arachidonic Acids/pharmacology
- Binding Sites/genetics
- Cattle
- Cell Line
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Dose-Response Relationship, Drug
- Humans
- Hydrogen-Ion Concentration
- Membrane Potentials/drug effects
- Mice
- Mutagenesis, Site-Directed/methods
- Mutation
- Nerve Tissue Proteins/antagonists & inhibitors
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/physiology
- Patch-Clamp Techniques
- Phosphorylation/drug effects
- Potassium Channels, Tandem Pore Domain/antagonists & inhibitors
- Potassium Channels, Tandem Pore Domain/genetics
- Potassium Channels, Tandem Pore Domain/physiology
- Protein Kinase C/metabolism
- Receptor, Muscarinic M3/genetics
- Receptor, Muscarinic M3/physiology
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/physiology
- Serum Albumin, Bovine/pharmacology
- Zinc/pharmacology
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Abstract
The ether-à-go-go (EAG) family of voltage-gated K(+) channels contains three subfamilies, EAG, ether-à-go-go related (ERG) and ether-à-go-go like (ELK). The human ether-à-go-go related gene (hERG) K(+) channel has been of significant interest because loss of function in the hERG channel is associated with a markedly increased risk of cardiac arrhythmias. The hERG channel has unusual kinetics with slow activation and deactivation but very rapid and voltage-dependent inactivation. The outer pore region of the hERG K(+) channel is predicted to be different from that of other members of the voltage-gated K(+) channel family. HERG has a much longer linker between the fifth transmembrane domain (SS) and the pore helix (S5P linker) compared to other families of voltage-gated K(+) channels (43 amino acids compared to 14-23 amino acids). Further, the S5P linker contains an amphipathic alpha-helix that in hERG channels probably interacts with the mouth of the pore to modulate inactivation. The human EAG and rat ELK2 channels (hEAG and rELK2) show reduced or no inactivation in comparison to hERG channels, yet both channels are predicted to contain a similarly long S5P linker to that of hERG. In this study, we have constructed a series of chimaeric channels consisting of the S1-S6 of hERG but with the S5P alpha-helical region of either hEAG or rELK2, and one consisting of the S1-S6 of rELK2 but with the S5P alpha-helical region of hERG to investigate the role of the S5P linker in inactivation. Our studies show that charged residues on the alpha-helix of the S5P linker contribute significantly to the differences in inactivation characteristics of the EAG family channels. Further, individually mutating each of the hydrophilic residues on the S5P alpha-helix of hERG to a charged residue had significant effects on the voltage dependence of inactivation and the two residues with the greatest affect when mutated to a lysine, N588 and Q592, both lie on the same face of the S5P alpha -helix. We suggest that inactivation of hERG involves the interaction of this face of the S5P alpha-helix with a charged residue on the remainder of the outer pore domain of the channel.
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Effects of dyskinesias in Parkinson's disease on quality of life and health-related costs: a prospective European study. Eur J Neurol 2006; 12:956-63. [PMID: 16324089 DOI: 10.1111/j.1468-1331.2005.01096.x] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The treatment of Parkinson's disease (PD) with l-DOPA leads to involuntary movements (dyskinesias). This 6-month observational study in three European countries in PD patients with various degrees of motor complications examined the effects of dyskinesias on the quality of life (QoL) of patients and health care costs. Retrospective and prospective health economic data were collected, and QoL of patients was measured using the Short Form-36 (SF-36) and the PD Quality of Life (PDQL) Scale. Regression analysis was used to estimate the adjusted effects of dyskinesias on QoL and costs, whilst accounting for the potentially confounding effects of disease progression, motor fluctuations and country. Increasing dyskinesia scores on either the Unified PD Rating Scale or the Goetz Dyskinesia Rating Scale were associated with significant reductions in QoL scores on the SF-36 and PDQL Scale. Increasing dyskinesia severity was also associated with increased depression scores on the Montgomery-Asberg Depression Rating Scale along with significant increases in health care costs. The effects of dyskinesia on QoL, depression and costs decreased but remained significant after adjustment for the confounding effects of disease progression and motor fluctuations. In conclusion, dyskinesias may adversely affect QoL and increase health care costs in patients with PD. Future studies should evaluate the potentially beneficial effects in terms of QoL and health care costs of strategies to delay the onset of, or the treatment of, dyskinesias.
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Ability of a nurse specialist to diagnose simple headache disorders compared with consultant neurologists. J Neurol Neurosurg Psychiatry 2005; 76:1170-2. [PMID: 16024902 PMCID: PMC1739753 DOI: 10.1136/jnnp.2004.057968] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To compare the ability of a headache nurse specialist and consultant neurologists in diagnosing tension-type headache and migraine. METHODS An experienced neurology ward sister was trained in the differential diagnosis of headache disorders. Over six months, patients with non-acute headache disorders and role players trained to present with benign or sinister headaches were seen by both the nurse and a consultant neurologist. Both reached independent diagnoses of various headache disorders. RESULTS Consultants diagnosed 239 patients with tension-type headache (47%), migraine (39%), or other headache disorders (14%). The nurse agreed with the consultant in 92% of cases of tension-type headache, 91% of migraine, and 61% of other diagnoses. Where the nurse did not agree with the diagnosis, most would have been referred for a consultant opinion. Both the nurse and the doctors misdiagnosed the same three of 13 role players. The investigation rate of the consultants varied between 18% and 59%. Only one clinically relevant abnormality was found on head scans and this was strongly suspected clinically. CONCLUSIONS A headache nurse specialist can be trained to diagnose tension-type headache and migraine. A nationwide nurse led diagnostic headache service could lead to substantial reduction in neurology waiting times.
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Efficacy of methyprednisolone pulse therapy on neuroleptic malignant syndrome in Parkinson's disease. J Neurol Neurosurg Psychiatry 2004; 75:510-1; author reply 511. [PMID: 14966183 PMCID: PMC1738992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
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Abstract
Depression is the most common psychiatric disturbance in Parkinson's disease. We conducted a Cochrane systematic review to assess the efficacy and safety of antidepressant therapies in idiopathic Parkinson's disease. Relevant trials were identified from electronic databases, reference lists and queries to antidepressant manufacturers. Three randomised controlled trials examined oral antidepressants in 106 patients with Parkinson's disease. No eligible trials of electroconvulsive or behavioural therapy were found. In the first arm of the crossover trial by Andersen et al. (n=22), nortriptyline treated patients showed a larger improvement than placebo in a unique depression rating scale after 16 weeks although significance levels were not provided. A parallel group trial by Wermuth et al. (n=37) did not show any significant difference between citalopram and placebo in Hamilton score after 52 weeks. Rabey et al. (n=47) performed an open-label trial comparing fluvoxamine with amitriptyline. Similar numbers in each group had a 50% reduction in Hamilton score after 16 months. Major side effects including visual hallucinations and confusion were reported with fluvoxamine and amitriptyline. Insufficient data on the effectiveness and safety of antidepressant therapies in Parkinson's disease are available on which to make recommendations for their use. Large scale randomised controlled trials are urgently required.
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Abstract
There has been a striking resurgence of interest in surgery for Parkinson's disease (PD) with new targets identified and new procedures developed. This systematic review identified over 500 studies of surgery for PD published since 1990, including over 10 000 patients. However, the authors were unable to assess the value of PD surgery reliably because only seven randomised trials were identified including just 196 patients. Studies of surgery for PD have generally been of poor quality with too few patients, too short follow up, inappropriate choice of outcome measures, and lack of control groups. Much larger, randomised, controlled trials are needed to assess the longer term effects of surgery on patient rated quality of life and cost effectiveness.
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Abstract
Brachial plexus injury is an unusual and under-recognised complication of coronary artery bypass grafting especially when internal mammary artery harvesting takes place. It is believed to be due to sternal retraction resulting in compression of the brachial plexus. Although the majority of cases are transient, there are cases where the injury is permanent and may have severe implications as illustrated in the accompanying case history.
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Dopamine agonist monotherapy in early Parkinson's disease. HOSPITAL MEDICINE (LONDON, ENGLAND : 1998) 2003; 64:8-11. [PMID: 12572327 DOI: 10.12968/hosp.2003.64.1.1836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
While levodopa therapy for Parkinson's disease is still considered the gold standard, motor complications are significant disadvantages of treatment. Monotherapy with dopamine agonists may present an alternative approach with a reduced likelihood of developing dyskinesias. Further studies are required before a definitive judgment can be made.
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Abstract
BACKGROUND Although levodopa is the most common drug prescribed to relieve the symptoms of Parkinson's disease it is associated with motor and psychiatric side-effects. Consequently, interest has turned to alternative drugs with improved side-effect profiles to replace or augment levodopa. Amantadine, originally used as an antiviral drug, has been shown to improve the symptoms of Parkinson's disease. OBJECTIVES To compare the efficacy and safety of amantadine therapy (monotherapy or adjuvant therapy) versus placebo in treating people with Parkinson's disease. SEARCH STRATEGY Electronic searches of The Cochrane Controlled Trials Register (The Cochrane Library Issue 3, 2001), MEDLINE (1966-2001), EMBASE (1974-2001), SCISEARCH (1974-2001), BIOSIS (1993-2001), GEROLIT (1979-2001), OLDMEDLINE (1957-1965), LILACS (1982-2001), MedCarib (17th Century - 2001), PASCAL (1973-2001), JICST-EPLUS (1985-2001), RUSSMED (1973-2001), DISSERTATION ABSTRACTS (2000-2001), SIGLE (1980-2001), ISI-ISTP (1990-2001), Aslib Index to Theses (2001), Clinicaltrials.gov (2001), metaRegister of Controlled Trials (2001), NIDRR (2001) and NRR (2001) were conducted. Grey literature was hand searched and the reference lists of identified studies and reviews examined. The manufacturers of amantadine were contacted. SELECTION CRITERIA Randomised controlled trials comparing amantadine with placebo in the treatment of patients with a clinical diagnosis of idiopathic Parkinson's disease. DATA COLLECTION AND ANALYSIS Data was abstracted independently by NC and KD onto standardised forms and disagreements were resolved by discussion. MAIN RESULTS Six randomised controlled trials were found comparing amantadine monotherapy or adjuvant therapy with placebo in the treatment of idiopathic Parkinson's disease. Five examined amantadine as adjuvant therapy with optimal levels of levodopa or anticholinergics and one examined amantadine as an adjuvant therapy with minimum tolerated levels of anticholinergics or as a monotherapy. Five were double-blind cross-over studies and one was a double-blind parallel group study. In total they examined 215 patients. The parallel group study allowed the randomisation codes to be broken and allowed patients in the placebo group to then receive amantadine. This could have led to bias. One study did not present the results of the placebo arm of the trial, hence we could not determine the difference between the two treatment groups. Two cross-over studies presented the results of the combined data from both treatment and placebo arms. The risk of carry-over effect into the second arm meant that these results could not be analysed. The final two studies presented at least some of their data from the end of the first arm of the trials. However only means were given, without standard deviations, so we could not determine the statistical significance of any difference between the amantadine and placebo groups. Although the authors did report on the side-effects from amantadine (such as livido recticularis, dry mouth and blurred vision), they state that none of them were severe. REVIEWER'S CONCLUSIONS A considerable amount of evidence on the effectiveness of amantadine has accrued from non-controlled trials, often in patients with Parkinsonian conditions other than idiopathic Parkinson's disease. However, rigorous analysis of the six randomised controlled trials of amantadine reveals insufficient evidence of its efficacy and safety in the treatment of idiopathic Parkinson's disease.
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Abstract
BACKGROUND The tremor of Parkinson's disease can cause considerable disability for the individual concerned. Traditional antiparkinsonian therapies such as levodopa have only a minor effect on tremor. Beta-blockers are used to attenuate other forms of tremor such as Essential Tremor or the tremor associated with anxiety. It is thought that beta-blockers may be of use in controlling the tremor of Parkinson's disease. OBJECTIVES To compare the efficacy and safety of adjuvant beta-blocker therapy against placebo for the treatment of tremor in patients with Parkinson's disease. SEARCH STRATEGY Electronic searches of MEDLINE, EMBASE, SCISEARCH, BIOSIS, GEROLIT, OLDMEDLINE, LILACS, MedCarib, PASCAL, JICST-EPLUS, RUSSMED, DISSERTATION ABSTRACTS, SIGLE, ISI-ISTP, Aslib Index to Theses, The Cochrane Controlled Trials Register, Clinicaltrials.gov, metaRegister of Controlled Trials, NIDRR, NRR and CENTRAL were conducted. Grey literature was hand searched and the reference lists of identified studies and reviews examined. The manufacturers of beta-blockers were contacted. SELECTION CRITERIA Randomised controlled trials of adjuvant beta-blocker therapy versus placebo in patients with a clinical diagnosis of idiopathic Parkinson's disease. DATA COLLECTION AND ANALYSIS Data was abstracted independently by two of the authors onto standardised forms and disagreements were resolved by discussion. MAIN RESULTS Four randomised controlled trials were found comparing beta-blocker therapy with placebo in patients with idiopathic Parkinson's disease. These were double-blind cross-over studies involving a total of 72 patients. Three studies did not present data from the first arm, instead presenting results as combined data from both treatment arms and both placebo arms. The risk of a carry-over effect into the second arm meant that these results were not analysed. The fourth study presented data from each arm. This was in the form of a mean total score for tremor for each group. Details of the baseline scores, the numbers of patients in each group and standard deviations were not provided, meaning that the magnitude and significance of any changes due to therapy could not be calculated. One study reported a substantial fall in heart rate in 14 of the 22 patients, with one patient withdrawing after his heart rate dropped to 56 beats per minute (baseline heart rate was not reported). REVIEWER'S CONCLUSIONS In view of this lack of evidence, it is impossible to determine whether beta-blocker therapy is effective and safe for the treatment of tremor in Parkinson's disease. The high frequency of bradycardia in one trial raises some concerns about the prescription of beta-blockers to normotensive elderly patients but the study was too small for the true degree of risk to be calculated.
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Abstract
BACKGROUND Abnormal involuntary movements known as dyskinesias are amongst the most disabling side-effects of levodopa therapy. It is thought that amantadine, an NMDA-receptor antagonist, may reduce dyskinesias in patients with Parkinson's disease without worsening Parkinsonian symptoms. OBJECTIVES To compare the efficacy and safety of adjuvant amantadine therapy versus placebo in treating dyskinesia in patients with Parkinson's disease, already established on levodopa, and suffering from motor complications. SEARCH STRATEGY Electronic searches of The Cochrane Controlled Trials Register (The Cochrane Library Issue 3, 2001), MEDLINE (1966-2001), EMBASE (1974-2001), SCISEARCH (1974-2001), BIOSIS (1993-2001), GEROLIT (1979-2001), OLDMEDLINE (1957-1965), LILACS (1982-2001), MedCarib (17th Century - 2001), PASCAL (1973-2001), JICST-EPLUS (1985-2001), RUSSMED (1973-2001), DISSERTATION ABSTRACTS (2000-2001), SIGLE (1980-2001), ISI-ISTP (1990-2001), Aslib Index to Theses (2001), Clinicaltrials.gov (2001), metaRegister of Controlled Trials (2001), NIDRR (2001) and NRR (2001) were conducted. Grey literature was hand searched and the reference lists of identified studies and reviews examined. The manufacturers of amantadine were contacted. SELECTION CRITERIA Randomised controlled trials comparing amantadine with placebo in the treatment of dyskinesia in patients with a clinical diagnosis of idiopathic Parkinson's disease. DATA COLLECTION AND ANALYSIS Data was abstracted independently by NC and KD onto standardised forms and disagreements were resolved by discussion. MAIN RESULTS Three randomised controlled trials were found comparing amantadine with placebo in the treatment of dyskinesia in patients with idiopathic Parkinson's disease. Three trials were excluded on the basis that they had no control group and a further three did not state whether they randomised the treatment that participants received. The included trials were double-blind cross-over studies involving a total of 53 patients. All three studies failed to present data from the first arm, instead presenting results as combined data from both treatment arms and both placebo arms. Two trials had no wash-out interval between the treatment periods. In view of the risk of a carry-over effect into the second arm, the results of these trials were not analysed. The final trial had a one week wash-out interval but only examined 11 participants. One study reported side-effects of amantadine in 8 of the 18 participants, including confusion and worsening of hallucinations. Another reported reversible edema of both feet in one of eleven participants. REVIEWER'S CONCLUSIONS Due to lack of evidence it is impossible to determine whether amantadine is a safe and effective form of treatment for levodopa-induced dyskinesias in patients with Parkinson's disease.
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Abstract
CONTEXT Levodopa is the gold-standard therapy for Parkinson's disease. However, long-term treatment leads to involuntary movements and response fluctuations which add to the complexities of later disease-management. In addition, preclinical evidence suggests that levodopa is toxic to dopaminergic neurons. These problems have led to a move away from levodopa towards initial monotherapy with a dopamine agonist. STARTING POINT Positron-emission tomography (PET) and single-photon emission computed tomography (SPECT) tracers have been developed which may be considered surrogate markers for remaining dopaminergic neurons. In a randomised controlled trial in patients with early Parkinson's disease, the Parkinson Study Group used 123I-beta-CIT SPECT (JAMA 2002; 287: 1653-61). Those patients given pramipexole had significantly reduced loss of striatal uptake at 46 months compared with those given levodopa (16.0% vs 25.5%). In a similar trial, Alan Whone and colleagues used 18F-DOPA PET (Neurology 2002; 58 [suppl 3]: A82-83). Patients given ropinirole had significantly reduced loss of striatal uptake at 24 months compared with those given levodopa (13% vs 20%). These studies suggest that agonist monotherapy may be neuroprotective and/or that levodopa is toxic. This work has been criticised as the SPECT results may have resulted from a differential effect of the agonist and levodopa on the regulation of the dopamine transporter, thereby influencing the imaging outcome measure. Other criticisms include insufficient data on the use of the potential neuroprotectant selegiline and patients on pramipexole in the SPECT study appear to have been clinically slow progressors. Single clinical trials with each of the four modern agonists compared with levodopa show that as monotherapy the agonists delay the onset of involuntary movements, although at the expense of poorer treatment of motor impairments and disability and more dopaminergic adverse events. The only health-related quality of life data show no difference between pramipexole and levodopa after 4 years. No information on health-economics measures is available but agonists cost two to three times as much as levodopa. WHERE NEXT? Young patients should be treated with agonist monotherapy since the trials included predominantly younger patients who have a higher incidence of motor complications. Those with significant co-morbidity, dementia, or a short life-expectancy should be treated with the lowest dose of levodopa required to maintain motor function. For the vast majority though, no clear guidance can be given. Further large-scale pragmatic trials in large numbers of patients over prolonged periods are urgently required.
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Abstract
The causative relationship between levodopa and the long-term motor complications of therapy, along with the possibility that levodopa may be toxic to dopaminergic neurones in vivo, has led to a move away from its use in early Parkinson's disease. Alternatives such as amantadine and the anticholinergics suffer from poor efficacy in comparison and a high side effect profile. Selegiline is probably less effective than levodopa and the issue of its safety versus neuroprotective properties remains unresolved. Long-term trials with the old and newer dopamine agonists as monotherapy have shown that as a class they can delay the development of dyskinesia and probably response fluctuations. However, major uncertainties remain about their use as monotherapy in all patients instead of levodopa. No data on their effect on quality of life and health care costs are available. Most of the trials were heavily biased towards younger patients with Parkinson's disease, so little data in the elderly are available. In later disease when patients have already developed motor complications on levodopa, the choice rests between adjuvant therapy with a dopamine agonist, a catechol-O-methyltransferase inhibitor (COMT; e.g. entacapone), and a monoamine oxidase B inhibitor (MAO B; e.g. selegiline). Trials with the former two classes have confirmed that they can reduce 'off' time, reduce levodopa dose, and improve motor impairments and disabilities with acceptable increases in adverse events including dyskinesia. Trials with selegiline as adjuvant therapy were less rigorous but it can allow a reduction in levodopa dose and motor impairments. No studies have compared these three classes of drug as adjuvant therapy so there is no evidence on which to base rational decisions in this type of patient. A large pragmatic trial which includes older patients is needed to clarify which treatment is best for different stages of the disease.
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Abstract
It has been suggested that proton magnetic resonance spectroscopy (MRS) of the striatum can differentiate between parkinsonian syndromes. The present study aims to examine this claim by performing a systematic review of the existing literature. A MEDLINE search was performed between 1966 and October 1999, along with searches of conference abstracts and reference lists of papers identified. Eleven groups have used MRS to examine metabolite ratios in the striatum in Parkinsonian syndromes. A number of these have shown reduced N-acetylaspartate/choline (NAA/Cho) and/or N-acetylaspartate/creatine (NAA/Cr) ratios in either idiopathic Parkinson's disease (IPD), multiple system atrophy (MSA), progressive supranuclear palsy (PSP) or corticobasal degeneration. However, the heterogeneity in the results precludes the use of any of these findings in differential diagnosis at the present time. The only group to use absolute metabolite concentrations rather than ratios showed that the decreased NAA/Cho ratio in IPD was because of an increase in choline which is of uncertain biological significance. Further large multicentre trials are required using absolute quantitation of tissue metabolite concentrations and a standardized technique. The patients entering such studies must be rigorously assessed to establish the diagnosis of the type of parkinsonism as accurately as possible. Any discriminatory abnormality must be tested in a large prospective study of newly presenting parkinsonian patients with long-term clinical follow up and ultimate pathological confirmation of the diagnosis as far as possible.
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Updated guidelines for the management of Parkinson's disease. HOSPITAL MEDICINE (LONDON, ENGLAND : 1998) 2001; 62:456-70. [PMID: 11530583 DOI: 10.12968/hosp.2001.62.8.1621] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
New data on diagnosis, drug therapy, surgery and psychosocial concerns have emerged since the publication of the 1998 Guidelines for the Management of Parkinson's Disease. This article reviews new data and addresses issues left unanswered in the previous guidelines.
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[Parkinson disease]. PRAXIS 2001; 90:1041-1046. [PMID: 11447724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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A randomized, double-blind, placebo-controlled, ascending-dose tolerability and safety study of remacemide as adjuvant therapy in Parkinson's disease with response fluctuations. Clin Neuropharmacol 2001; 24:133-8. [PMID: 11391123 DOI: 10.1097/00002826-200105000-00003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The objective of this study was to establish the maximum tolerated dose of the low affinity non-competitive N-methyl-D-aspartate receptor antagonist remacemide in patients who have Parkinson's disease with response fluctuations or dyskinesias, or both. A total of 33 patients were randomly assigned in a 3-to-1 ratio to receive remacemide or placebo. Remacemide was administered orally at 150 mg twice daily, increasing incrementally by 100 mg (50 mg twice daily) at 2-week intervals to a final daily regimen of 400 mg twice daily or until a maximum tolerated dose was identified. The maximum total treatment period was 12 weeks. Of the 23 patients randomly selected to receive remacemide, four completed the study at the maximum permitted dose, compared with four of the 10 patients given placebo. The median maximum tolerated dose of remacemide was 450 mg/d. There was no clinically relevant change in percentage of "on" time between baseline and maximum tolerated dose in either group. At the maximum tolerated dose of remacemide for each patient, the mean Unified Parkinson's Disease Rating Scale (UPDRS) motor examination score (part III) decreased from 33 (SD = 18) to 26 (SD = 13) compared with a decrease from 28 (SD = 12) to 27 (SD = 8) in the placebo group. There was a decrease in the mean UPDRS "complications of therapy" score (part IV) in the remacemide group from 8 (SD = 4) to 6 (SD = 4), and the placebo group remained unchanged at 6 (SD = 4). The most common adverse events associated with remacemide were nausea, vomiting, dizziness, headache, abnormal vision, and hypokinesia. Remacemide was well tolerated at a dose level of 400 mg/d. There was a trend suggesting that remacemide was effective in improving symptoms at patients' individual maximum tolerated doses. These improvements occurred without exacerbating levodopa-induced dyskinesias.
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Abstract
BACKGROUND Despite optimal medical and surgical therapies for Parkinson's disease, patients develop progressive disability. The role of the physiotherapist is to maximise functional ability and minimise secondary complications through movement rehabilitation within a context of education and support for the whole person. What form of physiotherapy is most effective in the treatment of Parkinson's disease remains unclear. OBJECTIVES 1. To compare the efficacy and effectiveness of novel physiotherapy techniques versus 'standard' physiotherapy in patients with Parkinson's disease. Standard physiotherapy is defined as the type of therapy that the physiotherapist would usually use to treat Parkinson's disease. 2. To compare the efficacy and effectiveness of one physiotherapy technique versus a second form of physiotherapy. SEARCH STRATEGY Relevant trials were identified by electronic searches of MEDLINE, EMBASE, CINAHL, ISI-SCI, AMED, MANTIS, REHABDATA, REHADAT, GEROLIT, Pascal, LILACS, MedCarib, JICST-EPlus, AIM, IMEMR, SIGLE, ISI-ISTP, DISSABS, Conference Papers Index, Aslib Index to Theses, the Cochrane Controlled Trials Register, the CentreWatch Clinical Trials listing service, the metaRegister of Controlled Trials, ClinicalTrials.gov, CRISP, PEDro, NIDRR and NRR; and examination of the reference lists of identified studies and other reviews. SELECTION CRITERIA Only randomised controlled trials (RCT) were included. DATA COLLECTION AND ANALYSIS Data was abstracted independently by KD and CEH and differences settled by discussion. MAIN RESULTS Seven trials were identified with 142 patients. All used small numbers of patients and the method of randomisation and concealment of allocation was poor or not statedin all of the trials. These methodological problems could potentially lead to bias from a number of sources. The methods of physiotherapy varied so widely that the data could not be combined. REVIEWER'S CONCLUSIONS Considering the small number of patients examined, the methodological flaws in many of the studies and the possibility of publication bias, there is insufficient evidence to support or refute the efficacy of any given form of physiotherapy over another in Parkinson's disease. Another Cochrane review, Physiotherapy for patients with Parkinson's Disease, found that there was insufficient evidence to support or refute the efficacy of physiotherapy compared to no physiotherapy in Parkinson's disease. A wide range of physiotherapy approaches were used in these studies and a survey of UK physiotherapists confirmed that they also use an eclectic combination of techniques in the treatment of Parkinson's disease (Plant 1999). Therefore a consensus must be found as to 'best practice' physiotherapy for Parkinson's disease. The efficacy of 'standard' physiotherapy should be proved first before examining variations in physiotherapy methods. Therefore large well designed randomised controlled trials are needed to judge the effect of physiotherapy in Parkinson's disease. After this large RCTs are needed to demonstrate the most effective form of physiotherapy in Parkinson's disease. Outcome measures with particular relevance to patients, carers, physiotherapists and physicians should be chosen and the patients monitored for at least 6 months to determine the duration of any effect. The trials should be reported according to CONSORT guidelines (CONSORT 1996).
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Abstract
BACKGROUND Dysarthria is a common manifestation of Parkinson's disease which increases in frequency and intensity with the progress of the disease (Streifler 1984). Up to 20% of Parkinsonian patients are referred for speech and language therapy (S & L T), its aim being to improve the intelligibility of the patient's speech. OBJECTIVES To compare the efficacy of speech and language therapy versus placebo or no interventions in patients with Parkinson's disease. SEARCH STRATEGY Relevant trials were identified by electronic searches of MEDLINE, EMBASE, CINAHL, ISI-SCI, AMED, MANTIS, REHABDATA, REHADAT, GEROLIT, Pascal, LILACS, MedCarib, JICST-EPlus, AIM, IMEMR, SIGLE, ISI-ISTP, DISSABS, Conference Papers Index, Aslib Index to Theses, the Cochrane Controlled Trials Register, the CentreWatch Clinical Trials listing service, the metaRegister of Controlled Trials, ClinicalTrials.gov, CRISP, PEDro, NIDRR and NRR; and examination of the reference lists of identified studies and other reviews. SELECTION CRITERIA Only randomised controlled trials (RCT) were included. DATA COLLECTION AND ANALYSIS Data were abstracted independently by KD and RW and differences settled by discussion. MAIN RESULTS Three randomised controlled trials were found comparing speech and language therapy with placebo for speech disorders in Parkinson's disease. A total of 63 patients were examined. The loudness of the patients' voices were increased by between 7-18%, depending on the speaking task being performed. It is likely that this is a clinically significant improvement. After six months the degree of improvement was reduced but was still statistically significant. Overall measures of dysarthria were measured in two trials and also improved. The clinical significance of these improvements was less clear cut as intelligibility of speech was not measured in any of these studies. REVIEWER'S CONCLUSIONS Considering the small number of patients examined, the methodological flaws in many of the studies, and the possibility of publication bias, there is insufficient evidence to support or refute the efficacy of speech and language therapy for dysarthria in Parkinson's disease. A Delphi-style survey is needed to develop a consensus as to what is 'standard' S< for dysarthria in Parkinson's disease. Then a large well designed placebo-controlled RCT is needed to demonstrate speech and language therapy's effectiveness for dysarthria in Parkinson's disease. The trial should conform to CONSORT guidelines. Outcome measures with particular relevance to patients should be chosen and the patients followed for at least 6 months to determine the duration of any improvement.
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Abstract
BACKGROUND Despite drug and surgical therapies for Parkinson's disease, patients develop progressive disability. The role of the occupational therapist is to support the patient and help them maintain their usual level of self-care, work and leisure activities for as long as possible. When it is no longer possible to maintain their usual activities, occupational therapists support individuals in changing and adapting their relationship with their physical and social environment to develop new valued activities and roles. OBJECTIVES To compare the efficacy and effectiveness of occupational therapy with placebo or no interventions (control group) in patients with Parkinson's disease. SEARCH STRATEGY Relevant trials were identified by electronic searches of MEDLINE, EMBASE, CINAHL, ISI-SCI, AMED, MANTIS, REHABDATA, REHADAT, GEROLIT, Pascal, LILACS, MedCarib, JICST-EPlus, AIM, IMEMR, SIGLE, ISI-ISTP, DISSABS, Conference Papers Index, Aslib Index to Theses, the Cochrane Controlled Trials Register, the CentreWatch Clinical Trials listing service, the metaRegister of Controlled Trials, ClinicalTrials.gov, CRISP, PEDro, NIDRR and NRR; and the reference lists of identified studies and other reviews were examined. SELECTION CRITERIA Only randomised controlled trials (RCT) were included, however those trials that allowed quasi-random methods of allocation were allowed. DATA COLLECTION AND ANALYSIS Data was abstracted independently by two authors and differences were settled by discussion. MAIN RESULTS Two trials were identified with 84 patients in total. Although both trials reported a positive effect from occupational therapy, all of the improvements were small. The trials did not have adequate placebo treatments, used small numbers of patients and the method of randomisation and concealment of allocation was not specified in one trial. These methodological problems could potentially lead to bias from a number of sources reducing the strength of the studies further. REVIEWER'S CONCLUSIONS Considering the significant methodological flaws in the studies, the small number of patients examined, and the possibility of publication bias, there is insufficient evidence to support or refute the efficacy of occupational therapy in Parkinson's disease. There does not appear to be a consensus as to the best practice in occupational therapy when treating people with Parkinson's disease. A survey of therapists is needed to determine what methods of occupational therapy are currently being used by therapists to treat Parkinson's disease, and whether there is a consensus as to 'best-practice'. Large well designed placebo-controlled RCTs are needed to demonstrate occupational therapy's effectiveness in Parkinson's disease. Outcome measures with particular relevance to patients, carers, occupational therapists and physicians should be chosen and the patients monitored for at least six months to determine the duration of benefit. The trials should be reported using CONSORT guidelines.
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Abstract
BACKGROUND Dysarthria is a common manifestation of Parkinson's disease that increases in frequency and intensity with the progress of the disease (Streifler 1984). Up to 20% of Parkinsonian patients are referred for speech and language therapy (S & LT), its aim being to improve the intelligibility of the patient's speech. OBJECTIVES To compare the efficacy and effectiveness of novel S & LT techniques versus standard S & LT to treat dysarthria in patients with Parkinson's disease. To compare the efficacy and effectiveness of one S & LT technique versus a second form of S & LT to treat Parkinsonian dysarthria. SEARCH STRATEGY Relevant trials were identified by electronic searches of MEDLINE, EMBASE, CINAHL, ISI-SCI, AMED, MANTIS, REHABDATA, REHADAT, GEROLIT, Pascal, LILACS, MedCarib, JICST-EPlus, AIM, IMEMR, SIGLE, ISI-ISTP, DISSABS, Conference Papers Index, Aslib Index to Theses, the Cochrane Controlled Trials Register, the CentreWatch Clinical Trials listing service, the metaRegister of Controlled Trials, ClinicalTrials.gov, CRISP, PEDro, NIDRR and NRR; and examination of the reference lists of identified studies and other reviews. SELECTION CRITERIA Only randomised controlled trials (RCT) were included. DATA COLLECTION AND ANALYSIS Data was abstracted independently by KD and RW and differences settled by discussion. MAIN RESULTS Only two trials were identified with only 71 patients. The method of randomisation was good in only one trial and the concealment of allocation was inadequate in both trials. These methodological problems could potentially lead to bias from a number of sources. The methods used in the two studies varied so much that meta-analysis of the results was not possible. Scott 83 compared prosodic exercises with visual cues with prosodic exercises alone (See Glossary: Table 01). The authors examined prosody and intelligibility as outcome measures immediately after therapy. Ramig 95 compared the Lee Silverman Voice Therapy (LSVT) which emphasises increased vocal effort, with respiratory therapy which aimed to increase respiratory muscle activity. Ramig 95 examined a wide range of vocal characteristics, activities of daily living affected by speech, depression and the carer's impressions of the patient's speech quality. Some of these outcomes were measured up to 24 months after the end of the therapy. However, in neither study were changes in outcomes due to 'Therapy A' compared with the changes due to 'Therapy B' statistically. Therefore no comment on the comparative efficacy of these types of speech and language therapy can be made. REVIEWER'S CONCLUSIONS Considering the methodological flaws in both of these studies, the small number of patients examined, and the possibility of publication bias, there is insufficient evidence to support or refute the efficacy of any given form of S & LT over another to treat dysarthria in Parkinson's disease. Given the lack of evidence from RCTs to support or refute the efficacy of S & LT in Parkinson's disease (see Cochrane review 'Speech and Language therapy for Dysarthria in Patients with Parkinson's Disease'), the consensus as to what is considered 'best-practice' S & LT must be proved first through a large well-designed placebo-controlled randomised trial before examining variations in S & LT methodology. The design of these trials should minimise bias and be reported fully using CONSORT guidelines (CONSORT 1996). Outcome measures with particular relevance to patients, their carers, physicians and speech and language therapists should be chosen and the patients followed for at least 6 months to determine the duration of any improvement.
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Abstract
BACKGROUND Despite optimal medical and surgical therapies for Parkinson's disease, patients develop progressive disability. The role of the physiotherapist is to maximise functional ability and minimise secondary complications through movement rehabilitation within a context of education and support for the whole person. OBJECTIVES To compare the efficacy and effectiveness of physiotherapy with placebo or no interventions in patients with Parkinson's disease. SEARCH STRATEGY Relevant trials were identified by electronic searches of MEDLINE, EMBASE, CINAHL, ISI-SCI, AMED, MANTIS, REHABDATA, REHADAT, GEROLIT, Pascal, LILACS, MedCarib, JICST-EPlus, AIM, IMEMR, SIGLE, ISI-ISTP, DISSABS, Conference Papers Index, Aslib Index to Theses, the Cochrane Controlled Trials Register, the CentreWatch Clinical Trials listing service, the metaRegister of Controlled Trials, ClinicalTrials.gov, CRISP, PEDro, NIDRR and NRR; and examination of the reference lists of identified studies and other reviews. SELECTION CRITERIA Only randomised controlled trials (RCT) were included, however those trials that allowed quasi-random methods of allocation were allowed. DATA COLLECTION AND ANALYSIS Data was abstracted independently by KD and DJ and differences settled by discussion. MAIN RESULTS Eleven trials were identified with 280 patients. Eight trials did not have adequate placebo treatments, all used small numbers of patients and the method of randomisation and concealment of allocation was good in only four trials. These methodological problems could potentially lead to bias from a number of sources. Although ten of the trials claimed a positive effect from physiotherapy, few outcomes measured were statistically significant. Walking velocity was measured in four trials and increased significantly in two of them. Stride length was the only other outcome measured in more than one trial, it was significantly improved in two trials. Five other outcomes improved significantly in individual studies, but eight other outcomes did not improve significantly. REVIEWER'S CONCLUSIONS Considering the methodological flaws in many of the studies, the small number of patients examined, and the possibility of publication bias, there is insufficient evidence to support or refute the efficacy of physiotherapy in Parkinson's disease. The studies illustrate that a wide range of approaches are being employed by physiotherapists to treat Parkinson's disease. This was confirmed by the UK survey of physiotherapists. There is a need to develop a consensus as to 'best-practice'. Large well designed placebo-controlled RCTs are then needed to demonstrate the efficacy and effectiveness of 'best practice' physiotherapy in Parkinson's disease. The stage of the disease at which the physiotherapy is given should be specified at the outset. Outcome measures with particular relevance to patients, carers, physiotherapists and physicians should be chosen and the patients monitored for at least six months to determine the duration of any beneficial effects. The trials should be reported according to CONSORT guidelines.
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Abstract
BACKGROUND Long-term levodopa therapy for Parkinson's disease is complicated by the development of motor fluctuations and abnormal involuntary movements. One approach is to add a dopamine agonist at this stage of the disease to reduce the time the patient spends immobile or off and to reduce the dose of levodopa in the hope of reducing such problems in the future. OBJECTIVES To compare the efficacy and safety of adjuvant ropinirole therapy versus placebo in patients with Parkinson's disease already established on levodopa therapy and suffering from motor complications. SEARCH STRATEGY Electronic searches of MEDLINE, EMBASE and the Cochrane Controlled Trials Register. Handsearching of the neurology literature as part of the Cochrane Movement Disorders Group's strategy. Examination of the reference lists of identified studies and other reviews. Contact with SmithKline Beecham. SELECTION CRITERIA Randomised controlled trials of ropinirole versus placebo in patients with a clinical diagnosis of idiopathic Parkinson's disease and long-term complications of levodopa therapy. DATA COLLECTION AND ANALYSIS Data was abstracted independently by the authors and differences settled by discussion. The outcome measures used included Parkinson's disease rating scales, levodopa dosage, 'off' time measurements and the frequency of withdrawals and adverse events. MAIN RESULTS Three double-blind, parallel group, randomised, controlled trials have been conducted on 263 patients. The two phase II studies were relatively small, were conducted over the short term (12 weeks), and used relatively low doses of ropinirole (mean administered doses 3.3 and 3.5 mg/d) in a twice daily regime. In view of this clinical heterogeneity and some statistical heterogeneity, the results of these trials have not been included in a meta-analysis. The conclusions of this review are based on the evidence from a single phase III study which was medium term (26 weeks) and used ropinirole doses in line with the current UK licensed maximum in a thrice daily regime. In view of difficulties in assessing changes in off time in ~~ Leiberman 98~~, caused by the initial imbalance between the arms of the trial, it is unsafe to draw any firm conclusion about the effect of ropinirole on off time. However, as an adverse event, dyskinesia was significantly increased in those who received ropinirole (~~ Leiberman 98~~; odds ratio 2.90; 1.36, 6.19 95% CI; Table 8). Measurements of motor impairments and disability were poor in this study with incomplete information available. Levodopa dose could be reduced in ~~ Leiberman 98~~ with a significantly larger reduction on ropinirole than on placebo (weighted mean difference 180 mg/d; 106, 253 95% CI; Table 2). No significant differences in the frequency of adverse event reports were noted between ropinirole and placebo apart from the increase in dyskinesia with ropinirole. There was a trend towards fewer withdrawals from ropinirole in ~~ Leiberman 98~~ but this did not reach statistical significance. REVIEWER'S CONCLUSIONS Ropinirole therapy can reduce levodopa dose but at the expense of increased dyskinetic adverse events. No clear effect on off time reduction was found but this may have been due to the under-powering of the single evaluable trial. Inadequate data on motor impairments and disability was collected to assess these outcomes. These conclusions apply to short and medium term treatment, up to 26 weeks. Further longer term trials are required, with measurements of effectiveness, and also studies to compare the newer with the older dopamine agonists.
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Basal ganglia metabolite concentrations in idiopathic Parkinson's disease and multiple system atrophy measured by proton magnetic resonance spectroscopy. Eur J Neurol 2000; 7:661-5. [PMID: 11136352 DOI: 10.1046/j.1468-1331.2000.00111.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Six patients with idiopathic Parkinson's disease (IPD), six with clinically probable multiple system atrophy and six control subjects underwent quantitative proton magnetic resonance spectroscopy (MRS). The concentrations of the three major metabolites, N-acetylaspartate (NAA), creatine and choline, were quantified in the lentiform nucleus using tissue water content as an internal concentration reference. Glutamate was assessed as the (glutamate + glutamine)/creatine peak area ratio (Glx/Cre). In the control subjects the mean (+/- SD) concentrations of the three metabolites were 15.2 +/- 2.9 micromol/g wet weight for NAA, 12.0 +/- 1.4 for creatine and 2.4 +/- 0.3 for choline. The Glx/Cre ratio was 1.28 +/- 0.32. The only significant difference in any metabolite concentration was in the lentiform nucleus of patients with IPD compared with controls, with an increase in choline which lead to a significant reduction in the NAA/choline ratio. The relevance of this finding is uncertain. The results of the present pilot study, combined with the conflicting findings from previous work, suggest that further, much larger, studies are required to evaluate the diagnostic capability of proton MRS.
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Systematic review of acute levodopa and apomorphine challenge tests in the diagnosis of idiopathic Parkinson's disease. J Neurol Neurosurg Psychiatry 2000; 69:590-4. [PMID: 11032609 PMCID: PMC1763425 DOI: 10.1136/jnnp.69.5.590] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES To perform a systematic review of studies examining the diagnostic accuracy of acute challenge tests with levodopa and/or apomorphine in parkinsonian syndromes to assess their value in the diagnosis of idiopathic Parkinson's disease. METHODS A literature search including Medline and the Cochrane Library was performed for studies published in any language comparing acute levodopa and/or apomorphine response with chronic levodopa therapy in parkinsonian syndromes. Abstracted sensitivity and specificity data were summarised using variance weighting and conditional logistic regression for studies comparing two challenge tests. RESULTS Thirteen studies were located: four examining de novo patients and nine examining patients with well established idiopathic Parkinson's disease and non-parkinsonian conditions. Despite the significant heterogeneity in the methodologies employed, the comparable results suggest that this had little effect on the accuracy of the tests. The sensitivity for the diagnosis of established idiopathic Parkinson's disease was: apomorphine 0.86 (95% confidence interval (95% CI) 0.78-0.94), acute levodopa 0.75 (95% CI 0.64-0.85), and chronic levodopa therapy 0.91 (95% CI 0.85-0.99). The specificity for the diagnosis of established idiopathic Parkinson's disease was: apomorphine 0.85 (95% CI 0.74-0.96), acute levodopa 0.87 (95% CI 0. 77-0.97), and chronic levodopa therapy 0.77 (95% CI 0.61-0.93). The number of patients positive for each test divided by the number with clinically diagnosed de novo disease was: apomorphine 0.63 (95% CI 0. 56-0.70), acute levodopa 0.69 (95% CI 0.59-0.80), and chronic levodopa therapy 0.76 (95% CI 0.70-0.82). CONCLUSIONS The accuracy of the acute levodopa and apomorphine challenge tests is similar to, but not superior than, that of chronic levodopa therapy in the diagnosis of idiopathic Parkinson's disease. As most patients will be given chronic dopamimetic therapy, these tests add nothing while causing significant adverse events and additional cost.
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A five-year study of the incidence of dyskinesia in patients with early Parkinson's disease who were treated with ropinirole or levodopa. N Engl J Med 2000; 342:1484-91. [PMID: 10816186 DOI: 10.1056/nejm200005183422004] [Citation(s) in RCA: 1114] [Impact Index Per Article: 46.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND There is debate about whether the initial treatment for patients with Parkinson's disease should be levodopa or a dopamine agonist. METHODS In this prospective, randomized, double-blind study, we compared the safety and efficacy of the dopamine D2-receptor agonist ropinirole with that of levodopa over a period of five years in 268 patients with early Parkinson's disease. If symptoms were not adequately controlled by the assigned study medication, patients could receive supplementary levodopa, administered in an open-label fashion. The primary outcome measure was the occurrence of dyskinesia. RESULTS Eighty-five of the 179 patients in the ropinirole group (47 percent) and 45 of the 89 patients in the levodopa group (51 percent) completed all five years of the study. In the ropinirole group 29 of the 85 patients (34 percent) received no levodopa supplementation. The analysis of the time to dyskinesia showed a significant difference in favor of ropinirole (hazard ratio for remaining free of dyskinesia, 2.82; 95 percent confidence interval, 1.78 to 4.44; P<0.001). At five years, the cumulative incidence of dyskinesia (excluding the three patients who had dyskinesia at base line), regardless of levodopa supplementation, was 20 percent (36 of 177 patients) in the ropinirole group and 45 percent (40 of 88 patients) in the levodopa group. There was no significant difference between the two groups in the mean change in scores for activities of daily living among those who completed the study. Adverse events led to the early withdrawal from the study of 48 of 179 patients in the ropinirole group (27 percent) and 29 of 89 patients in the levodopa group (33 percent). The mean (+/-SD) daily doses given by the end of the study were 16.5+/-6.6 mg of ropinirole (plus 427+/-221 mg of levodopa in patients who received supplementation) and 753+/-398 mg of levodopa (including supplements). CONCLUSIONS Early Parkinson's disease can be managed successfully for up to five years with a reduced risk of dyskinesia by initiating treatment with ropinirole alone and supplementing it with levodopa if necessary.
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Abstract
1. Effects of external pH on the human P2X4 purinoceptor, an ATP-activated ion channel, were studied using the Xenopus oocyte expression system. 2. Changing the external pH from 7.4 to 6.5 significantly reduced, whilst an increase to pH 8 enhanced, maximum ATP-activated current amplitude, without changing the current- voltage relationship of the ATP-activated current. 3. Diethyl pyrocarbonate (DEPC; 10 mM) treatment of P2X4-injected oocytes had no effect on the pH sensitivity of the ATP-activated current. 4. Site-directed mutagenesis of histidine 286 (H286) to alanine completely abolished the pH sensitivity of the P2X4 receptor at all agonist concentrations. ATP potency showed a small (fourfold) leftward shift. Mutagenesis of the other three histidines present in the P2X4 sequence had no effect on pH sensitivity. 5. The results show that pH modulation of P2X4 in the pathophysiological range is mediated by protonation of H286. This provides direct confirmation that pH sensitivity resides in the P2X4 channel protein rather than the agonist species.
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