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1.
Trop Biomed ; 38(3): 377-386, 2021 Sep 01.
Article in English | MEDLINE | ID: mdl-34508347

ABSTRACT

Intestinal parasitic infections are endemic in rural settings and may account for asymptomatic infections to various health complications. These infections are a cause of concern for communities of lower economic status, especially in developing countries. In Sarawak, indigenous populations residing in geographically inaccessible areas are socially and economically disadvantaged. Through close association with nature, these populations are prone to intestinal parasitism. Currently, scattered information has led to a continual state of neglect at each level of parasitic infection control. This urges for a review of their distribution and transmission based on previous reports to understand the pattern of the diseases in the state which can further address the improvement of mass controlling programs. A literature search was conducted to collect previous reports on human intestinal parasites in Sarawak, East Malaysia from PubMed (Medline), SCOPUS, ScienceDirect and Web of Science from January 2019 to March 2021. Extrapolating the current data in Sarawak which is still considered limited, further interdisciplinary strategies are demanded to give insights in the epidemiology and true prevalence of intestinal parasites in Sarawak. This review addresses for redirection of attitude towards intestinal parasitic infections where it should be given with ample attention by rural populations. In tandem to that, improvement of rural livelihood such as standard of living and sanitation in Sarawak should be accredited as part of the efforts to reduce the number of intestinal parasitic infections in the state. As a control measure, mass deworming should be reconsidered especially to the rural populations.


Subject(s)
Intestinal Diseases, Parasitic , Animals , Epidemiologic Studies , Humans , Intestinal Diseases, Parasitic/epidemiology , Malaysia/epidemiology , Prevalence , Risk Factors , Rural Population
2.
Tropical Biomedicine ; : 377-386, 2021.
Article in English | WPRIM (Western Pacific) | ID: wpr-906541

ABSTRACT

@#Intestinal parasitic infections are endemic in rural settings and may account for asymptomatic infections to various health complications. These infections are a cause of concern for communities of lower economic status, especially in developing countries. In Sarawak, indigenous populations residing in geographically inaccessible areas are socially and economically disadvantaged. Through close association with nature, these populations are prone to intestinal parasitism. Currently, scattered information has led to a continual state of neglect at each level of parasitic infection control. This urges for a review of their distribution and transmission based on previous reports to understand the pattern of the diseases in the state which can further address the improvement of mass controlling programs. A literature search was conducted to collect previous reports on human intestinal parasites in Sarawak, East Malaysia from PubMed (Medline), SCOPUS, ScienceDirect and Web of Science from January 2019 to March 2021. Extrapolating the current data in Sarawak which is still considered limited, further interdisciplinary strategies are demanded to give insights in the epidemiology and true prevalence of intestinal parasites in Sarawak. This review addresses for redirection of attitude towards intestinal parasitic infections where it should be given with ample attention by rural populations. In tandem to that, improvement of rural livelihood such as standard of living and sanitation in Sarawak should be accredited as part of the efforts to reduce the number of intestinal parasitic infections in the state. As a control measure, mass deworming should be reconsidered especially to the rural populations.

3.
Biosens Bioelectron ; 151: 111961, 2020 Mar 01.
Article in English | MEDLINE | ID: mdl-31868607

ABSTRACT

The direct electrical connection of laccase on the electrode surface is a key feature in the design of efficient and stable biocathodes. However, laccase can perform a direct electron transfer only when it is in the preferred orientation toward the electrode. Here we report the investigation of the orientation of laccase from white rot fungus on multi-walled carbon nanotube surface modified with a naphthalene group. Naphthylated multi wall carbon nanotubes were synthesized and the kinetics of laccase from white rot fungus adsorption and its direct electro-catalytic activity toward oxygen reduction was investigated by QCM and electrochemical techniques. Compared to pristine multi-walled carbon nanotubes laccase shows a high affinity to be adsorbed onto the surface of naphthylated carbon nanotubes at a very fast rate. The subsequent wiring to the naphthylated multi-walled carbon nanotubes is accompanied by a reorientation and arrangement of adsorbed laccase to create a composite biocathode that exhibits a high-performance for oxygen reduction by direct electron transfer with maximum current densities of 3 mA cm-2.


Subject(s)
Laccase/chemistry , Nanotubes, Carbon/chemistry , Naphthalenes/chemistry , Biosensing Techniques , Catalysis , Electrochemical Techniques , Electrodes , Electron Transport , Kinetics , Oxidation-Reduction , Oxygen/chemistry , Surface Properties
4.
Environ Sci Pollut Res Int ; 21(8): 5660-8, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24430496

ABSTRACT

Xenobiotics such as pesticides and pharmaceuticals are an increasingly large problem in aquatic environments. A fixed-bed adsorption filter, used as tertiary stage of sewage treatment, could be a solution to decrease xenobiotics concentrations in wastewater treatment plants (WWTPs) effluent. The adsorption efficiency of two mineral adsorbent materials (expanded clay (EC) and zeolite (ZE)), both seen as a possible alternative to activated carbon (AC), was evaluated in batch tests. Experiments involving secondary treated domestic wastewater spiked with a cocktail of ten xenobiotics (eight pharmaceuticals and two pesticides) known to be poorly eliminated in conventional biological process were carried out. Removal efficiencies and partitions coefficients were calculated for two levels of initial xenobiotic concentration, i.e, concentrations lower to 10 µg/L and concentrations ranged from 100 to 1,000 µg/L. While AC was the most efficient adsorbent material, both alternative adsorbent materials showed good adsorption efficiencies for all ten xenobiotics (from 50 to 100 % depending on the xenobiotic/adsorbent material pair). For all the targeted xenobiotics, at lower concentrations, EC presented the best adsorption potential with higher partition coefficients, confirming the results in terms of removal efficiencies. Nevertheless, Zeolite presents virtually the same adsorption potential for both high and low xenobiotics concentrations to be treated. According to this first batch investigation, ZE and EC could be used as alternative absorbent materials to AC in WWTP.


Subject(s)
Waste Disposal, Fluid/methods , Water Pollutants, Chemical/chemistry , Xenobiotics/chemistry , Zeolites/chemistry , Adsorption , Aluminum Silicates/chemistry , Charcoal/chemistry , Clay , Filtration , Wastewater/chemistry , Water Pollutants, Chemical/analysis , Xenobiotics/analysis
5.
Rev Med Interne ; 33(8): 453-6, 2012 Aug.
Article in French | MEDLINE | ID: mdl-22703872

ABSTRACT

INTRODUCTION: Wernicke's encephalopathy caused by thiamine deficiency is typically characterised by a mental-status change, oculomotor dysfunction and an ataxia. Pellagra is the clinical presentation of niacin deficiency comprising cutaneous, gastrointestinal and neuropsychiatric manifestations. OBSERVATION: We report a case of encephalopathy due to dual vitamin deficiency of both thiamine (vitamin B1) and niacin (vitamin PP) in an 80-year-old women, hospitalized for severe sepsis caused by aspiration pneumonia. Severe malnutrition and alcohol consumption pointed to a diagnosis of vitamin deficiency. The clinical presentation and magnetic resonance imaging (MRI) were compatible with Wernicke's encephalopathy that remained irreversible despite vitamin B1 supplementation. Niacin supplementation allowed for complete regression of the observed symptoms compatible with niacin deficiency. CONCLUSION: Malnourished and alcoholic patients showing signs of encephalopathy should receive supplemental multivitamins including niacin.


Subject(s)
Pellagra/complications , Pneumonia, Aspiration/complications , Wernicke Encephalopathy/etiology , Aged , Aged, 80 and over , Brain Diseases, Metabolic/diagnosis , Brain Diseases, Metabolic/etiology , Brain Diseases, Metabolic/therapy , Female , Hospitalization , Humans , Pellagra/diagnosis , Pellagra/etiology , Pellagra/therapy , Pneumonia, Aspiration/therapy , Wernicke Encephalopathy/diagnosis , Wernicke Encephalopathy/therapy
6.
Med J Malaysia ; 66(2): 84-8, 2011 Jun.
Article in English | MEDLINE | ID: mdl-22106682

ABSTRACT

Patient's satisfaction has become increasingly important as patients evaluate healthcare services for both medical cost and quality. The purpose of this study was to measure the prevalence and the factors influencing caregivers' satisfaction. A cross sectional study of 262 respondents using universal sampling method was conducted at the paediatric clinics of Universiti Kebangsaan Malaysia Medical Centre (UKMMC). Overall, 90.5% were satisfied with the services provided. Satisfaction rates based on various healthcare delivery domains were: 95.0% for communication skills, 88.5% for interpersonal aspect, 83.6% for technical quality, 82.1% for financial aspect, 72.9% for time spent with doctors and 64.9% for ease of contact. This study shows that the caregivers (an unpaid person who helps a person cope with disease) were highly satisfied with the communicational aspect delivered by the clinic. However, there is still room for improvement on ease of contact domain and waiting time in order to produce high quality service.


Subject(s)
Ambulatory Care Facilities , Attitude of Health Personnel , Caregivers , Delivery of Health Care/organization & administration , Pediatrics , Adult , Child , Cross-Sectional Studies , Female , Hospitals, University , Humans , Malaysia , Male , Patient Satisfaction
7.
Issues Emerg Health Technol ; (66): 1-4, 2005 Mar.
Article in English | MEDLINE | ID: mdl-15806747

ABSTRACT

Alemtuzumab, a humanized monoclonal antibody, is thought to destroy cancer cells through immune system stimulation or apoptosis induction (programmed cell death). In case series studies using alemtuzumab as salvage therapy, about a third of patients with B-cell chronic lymphocytic leukemia (B-CLL), who were otherwise refractory to chemotherapy, improved. Anti-tumour activity was also observed when the drug was used as first-line therapy or to treat minimal residual disease. Adverse events associated with alemtuzumab included "first-dose" flu-like symptoms, prolonged lymphopenia with a subsequent increased risk of opportunistic infections and viral reactivation (e.g., cytomegalovirus) and transient cytopenias. Data from randomized controlled trials (RCTs), focusing on clinical outcomes such as survival and patients' quality of life, are needed to accurately assess the harm and benefit of alemtuzumab.


Subject(s)
Antibodies, Monoclonal/therapeutic use , Antibodies, Neoplasm/therapeutic use , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Antibodies, Monoclonal/adverse effects , Antibodies, Neoplasm/adverse effects , Clinical Trials as Topic , Drug Costs , Humans , Infections , Randomized Controlled Trials as Topic , Treatment Outcome , United States , United States Food and Drug Administration
8.
Issues Emerg Health Technol ; (67): 1-4, 2005 Mar.
Article in English | MEDLINE | ID: mdl-15806748

ABSTRACT

Pregabalin is an anticonvulsant drug that is under review for use in Canada. It was recently approved in the US and Europe for the treatment of adults with peripheral neuropathic pain (NeP). In most short-term randomized controlled trials (RCTs) of pregabalin in patients with diabetic peripheral neuropathy (DPN) and or post-herpetic neuralgia (PHN), there were early and significant decreases in mean pain scores. The number of subjects with > 50% reduction in pain score was increased when pregabalin was compared to placebo. The most common adverse effects were dizziness and sleepiness. Withdrawal due to adverse events was also more frequent with pregabalin than with placebo. While pregabalin appears to be an effective treatment for NeP, there is no evidence that it offers advantages over treatments being used in Canada.


Subject(s)
Diabetic Neuropathies/drug therapy , gamma-Aminobutyric Acid/therapeutic use , Adolescent , Adult , Aged , Anticonvulsants/adverse effects , Anticonvulsants/economics , Anticonvulsants/therapeutic use , Canada , Drug Approval , Drug Costs , Europe , Female , Humans , Male , Middle Aged , Pain Measurement/drug effects , Pain Measurement/methods , Randomized Controlled Trials as Topic , United States , United States Food and Drug Administration , gamma-Aminobutyric Acid/adverse effects , gamma-Aminobutyric Acid/analogs & derivatives , gamma-Aminobutyric Acid/economics
9.
Behav Pharmacol ; 16(2): 107-12, 2005 Mar.
Article in English | MEDLINE | ID: mdl-15767846

ABSTRACT

Motor skills, once learned, need to be consolidated over time in order to become resistant to disruption or interference. In some instances, the consolidation phase can also include spontaneous gains in performance even in the absence of further rehearsal on a motor task. Clinical and behavioral evidence suggest that N-methyl-D-aspartate (NMDA)-receptor activity is required for motor learning acquisition and behavioral synaptic plasticity. However, the involvement of NMDA receptors in motor consolidation, leading to stabilization of the recently formed motor memory, has not yet been assessed in humans. To address this issue, we used post-training administration of amantadine, a low-affinity NMDA-receptor channel blocker. In a double-blind design, 200 mg of amantadine or a matching placebo was given orally to two different groups of 11 healthy young volunteers each. The subjects were tested twice 24 h apart, using a motor adaptation paradigm consisting of an eight-target-pointing task. Comparison of the mean performance levels on this task revealed that subjects in both groups improved their performance levels significantly on Day 2 compared to Day 1, regardless of the treatment administered. Our data indicate that amantadine failed to block motor learning consolidation in subjects that had already learned the motor adaptation task. Thus, although required in some stages (e.g. acquisition) of motor memory processes, the present results suggest that NMDA-receptor activation may not be essential for consolidation of motor adaptation in humans.


Subject(s)
Amantadine/pharmacology , Dopamine Agents/pharmacology , Memory/drug effects , Motor Skills , Receptors, N-Methyl-D-Aspartate/drug effects , Receptors, N-Methyl-D-Aspartate/physiology , Adaptation, Physiological , Adult , Double-Blind Method , Female , Humans , Male , Placebos
10.
Issues Emerg Health Technol ; (63): 1-4, 2004 Dec.
Article in English | MEDLINE | ID: mdl-15612152

ABSTRACT

Bevacizumab is a recombinant humanized monoclonal antibody that targets vascular endothelial growth factor (VEGF). It is thought that bevacizumab inhibits the formation of new blood vessels. Two clinical trials show that the addition of bevacizumab to a regimen of either fluorouracil plus leucovorin (FL) or FL combined with irinotecan (IFL), significantly improves response rate and time to tumour progression and increases overall survival for patients with advanced colorectal cancer (ACC). Thromboembolic events are the most clinically significant adverse events, but hypertension, hemorrhage and gastrointestinal perforation are other potential safety concerns. More studies are needed to compare the combination of bevacizumab plus IFL to other chemotherapy regimens used in the treatment of ACC. The addition of bevacizumab to 5-fluorouracil-based chemotherapy regimens will significantly increase the costs of palliation for ACC.


Subject(s)
Antibodies, Monoclonal/therapeutic use , Colorectal Neoplasms/drug therapy , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal/economics , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Antineoplastic Combined Chemotherapy Protocols/economics , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Camptothecin/administration & dosage , Camptothecin/analogs & derivatives , Canada , Clinical Trials as Topic , Clinical Trials, Phase II as Topic , Clinical Trials, Phase III as Topic , Colorectal Neoplasms/etiology , Colorectal Neoplasms/pathology , Drug Approval , Fluorouracil/administration & dosage , Humans , Leucovorin/administration & dosage , Treatment Outcome , United States , United States Food and Drug Administration , Vascular Endothelial Growth Factors
11.
Issues Emerg Health Technol ; (58): 1-4, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15455487

ABSTRACT

In the US, subcutaneous administration of omalizumab is indicated for adults and adolescents (age greater than or equal to 12 years) with allergic asthma that is moderate to severe and inadequately controlled with inhaled corticosteroids. In placebo-controlled trials, omalizumab reduces asthma exacerbations and the need for inhaled steroids in this group. The value of omalizumab to patients with severe asthma (e.g., refractory asthma) has yet to be proven. Data are lacking on the efficacy of omalizumab compared to add-on therapies such as inhaled long-acting beta-2 agonists or anti-leukotriene agents. Further evaluation on omalizumab needs to be done in the pediatric population.


Subject(s)
Anti-Allergic Agents/therapeutic use , Anti-Asthmatic Agents/therapeutic use , Antibodies, Monoclonal/therapeutic use , Asthma/drug therapy , Immunoglobulin E/immunology , Adolescent , Adult , Anti-Allergic Agents/administration & dosage , Anti-Allergic Agents/adverse effects , Anti-Asthmatic Agents/administration & dosage , Anti-Asthmatic Agents/adverse effects , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/adverse effects , Asthma/immunology , Australia , Canada , Child , Clinical Trials as Topic , Costs and Cost Analysis , Drug Approval , Humans , Hydrocortisone/therapeutic use , Immunoglobulin E/blood , Safety , Treatment Outcome , United States
13.
Rev Neurol (Paris) ; 159(12): 1125-42, 2003 Dec.
Article in French | MEDLINE | ID: mdl-14978413

ABSTRACT

Involuntary movements, or dyskinesias, represent a debilitating complication of levodopa therapy for Parkinson's disease. Dyskinesia is, ultimately, experienced by the vast majority of the patients. Despite the importance of this problem, little was known about the cause of dyskinesia, a situation that has dramatically evolved in the last few years. The present review presents: 1) the current understanding of dyskinesia pathophysiology and 2) the therapeutic modalities, mainly non-dopaminergic, available or in development. We here show that the questions raised by the dyskinesia may have a clinically-driven pharmacological answer: the symptomatic treatment of dyskinesia, the prevention of the priming and the de-priming of the neural networks.


Subject(s)
Dopamine Agents/adverse effects , Dyskinesia, Drug-Induced/drug therapy , Dyskinesia, Drug-Induced/physiopathology , Levodopa/adverse effects , Animals , Basal Ganglia/anatomy & histology , Basal Ganglia/physiology , Disease Models, Animal , Dyskinesia, Drug-Induced/prevention & control , Humans , Receptors, Adrenergic/drug effects , Receptors, Adrenergic/physiology , Receptors, Dopamine/drug effects , Receptors, Dopamine/physiology , Receptors, Glutamate/drug effects , Receptors, Glutamate/physiology , Receptors, Opioid/drug effects , Receptors, Opioid/physiology , Receptors, Purinergic P1/drug effects , Receptors, Purinergic P1/physiology
14.
Eur J Pharmacol ; 412(3): 247-54, 2001 Feb 02.
Article in English | MEDLINE | ID: mdl-11166288

ABSTRACT

(S)-(-)-3-(3-(methylsulfonyl)phenyl)-1-propylpiperidine ((-)-OSU6162) is a phenylpiperidine derivative which exhibits low affinity to the dopamine D2 receptor in vitro. However, in vivo, positron emission tomography scanning studies show that the compound displaces the selective dopamine D2 receptor antagonist, raclopride. We have evaluated, in this study, the effect of (-)-OSU6162, on L-3,4-dihydroxyphenylalanine (L-DOPA)-induced dyskinesias in a primate model of Parkinson's disease. Five 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated cynomolgus monkeys with a stable parkinsonian syndrome and reproducible dyskinesias to L-DOPA were used in this study. The monkeys were housed in observation cages equipped with an electronic motility monitoring system. They were injected subcutaneously (s.c.) with L-DOPA methyl ester (125 mg per animal) plus benserazide (50 mg per animal; L-DOPA/benserazide) alone or in combination with (-)-OSU6162 (1.0, 3.0, 6.0 or 10 mg/kg, s.c.). Subcutaneous injection of sterile saline was used as control. L-DOPA/benserazide increased locomotion and improved parkinsonism but also induced dyskinesias. Co-administration of (-)-OSU6162 with L-DOPA/benserazide produced a significant reduction in L-DOPA-induced dyskinesias. This improvement in L-DOPA-induced dyskinesias occurred mainly at the onset of the L-DOPA/benserazide effect as reflected by an increase in the duration of the "ON" state without dyskinesias up to 3.4 fold after (-)-OSU6162 co-administration as compared to L-DOPA/benserazide alone. The anti-dyskinetic effect of (-)-OSU6162 was maintained during 14 days and no tolerance to this effect was observed. Our data suggests that (-)-OSU6162 could be of significant clinical value to reduce L-DOPA-induced dyskinesias in fluctuating advanced Parkinson's disease patients.


Subject(s)
Dyskinesia, Drug-Induced/drug therapy , Levodopa/pharmacology , Parkinsonian Disorders/physiopathology , Piperidines/pharmacology , Receptors, Dopamine D2/metabolism , 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/pharmacology , Animals , Antiparkinson Agents/administration & dosage , Antiparkinson Agents/pharmacology , Benserazide/administration & dosage , Benserazide/pharmacology , Dopamine Agents/pharmacology , Dopamine Antagonists/pharmacology , Dopamine Antagonists/therapeutic use , Female , Humans , Levodopa/administration & dosage , Macaca fascicularis , Motor Activity/drug effects , Parkinsonian Disorders/drug therapy , Piperidines/therapeutic use
15.
Trends Neurosci ; 23(10 Suppl): S92-100, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11052226

ABSTRACT

The MPTP monkey is a well-characterized animal model of parkinsonism and provides an exceptional tool for the study of dyskinesias induced by dopamine-like agents. Several such agents have been tested during the past 15 years, and it has been found that the duration of action of these compounds is the most reliable variable with which to predict their dyskinesiogenic profile. It is proposed that L-dopa-induced dyskinesias represent a form of pathological learning caused by chronic pulsatile (nonphysiological) stimulation of dopamine receptors, which activates a cascade of molecular and biochemical events. These events include defective regulation of Fos proteins that belong to the deltaFosB family, increased expression of neuropeptides, and defective GABA- and glutamate-mediated neurotransmission in the output structures of the basal ganglia.


Subject(s)
Antiparkinson Agents/adverse effects , Basal Ganglia/drug effects , Dopamine Agonists/adverse effects , Dyskinesia, Drug-Induced/metabolism , Levodopa/adverse effects , Parkinsonian Disorders/metabolism , Receptors, Dopamine/drug effects , 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine , Animals , Antiparkinson Agents/administration & dosage , Basal Ganglia/metabolism , Disease Models, Animal , Dopamine Agonists/administration & dosage , Haplorhini , Levodopa/administration & dosage , Neural Inhibition , Neuropeptides/metabolism , Parkinsonian Disorders/chemically induced , Proto-Oncogene Proteins c-fos/metabolism , Receptors, Dopamine/metabolism , Receptors, GABA/metabolism , Receptors, Glutamate/metabolism , Signal Transduction
16.
Clin Neuropharmacol ; 23(4): 195-202, 2000.
Article in English | MEDLINE | ID: mdl-11020123

ABSTRACT

The pathophysiology of L-Dopa-induced dyskinesias (LID), a common problem after long-term use of L-dopa in the treatment of Parkinson's disease (PD), is not completely understood. Oscillations in L-Dopa concentrations in the brain are believed to be responsible, at least in part, for their pathogenesis. This study was aimed at verifying whether chronic administration of cabergoline, a long-acting dopamine D2-like receptor agonist, can reverse established LID. Four MPTP-treated cynomolgus monkeys with long-standing and stable parkinsonian syndrome and reproducible dyskinesias to L-Dopa, were used in this study. We compared the antiparkinsonian and dyskinetic responses of L-Dopa methyl ester (62.5 mg and 125 mg), given with benserazide (50 mg) (L-Dopa/benserazide), administered before and after a 6-week period during which the animals were treated only by daily administration of cabergoline (doses ranging from 0.125 to 0.185 mg/kg, subcutaneous). During cabergoline treatment, the monkeys initially showed marked dyskinesias, which were reduced significantly after 4 weeks of treatment. However, there was no tolerance to its antiparkinsonian effect. L-Dopa/benserazide given 4 days after cabergoline withdrawal produced a significant antiparkinsonian effect, but dyskinesias were dramatically reduced compared to what had been seen before chronic cabergoline treatment. The duration of the L-Dopa response was not increased after chronic administration of cabergoline. Our data suggest that sustained dopamine D2 receptor stimulation could be of value when trying to reduce or to reverse LID in patients with fluctuating advanced PD.


Subject(s)
Antiparkinson Agents/antagonists & inhibitors , Antiparkinson Agents/therapeutic use , Dyskinesia, Drug-Induced/drug therapy , Ergolines/therapeutic use , Levodopa/antagonists & inhibitors , Parkinson Disease, Secondary/complications , Animals , Antiparkinson Agents/toxicity , Behavior, Animal/drug effects , Benserazide/pharmacology , Cabergoline , Female , Levodopa/toxicity , Macaca fascicularis , Motor Activity/drug effects , Receptors, Dopamine D2/drug effects
17.
Eur J Pharmacol ; 399(2-3): 183-6, 2000 Jul 07.
Article in English | MEDLINE | ID: mdl-10884518

ABSTRACT

Clozapine reduces L-3,4-dihydroxyphenylalanine (L-Dopa)-induced dyskinesias in parkinsonian patients. To test if the antidyskinetic effect of clozapine is related to antagonism at the dopamine D(4) receptor, we investigated the effect of 8-methyl-6-(4-methyl-1-piperazinyl)-11H-pyrido[2,3-b][1, 4]benzodiazepine (JL-18), a structural analog of clozapine which is more selective for this receptor. Four 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine (MPTP)-treated cynomolgus monkeys with a stable parkinsonian syndrome and reproducible dyskinesias to L-Dopa were used in this study. They were injected subcutaneously (s.c.) with L-Dopa methyl ester (125 mg per animal) plus benserazide (50 mg per animal; L-Dopa/benserazide) alone or in combination with JL-18 (at the doses of 0.1, 0.3, or 0.9 mg/kg, s.c.). Subcutaneous injection of sterile saline was used as control. L-Dopa/benserazide increased locomotion and improved parkinsonism but also induced dyskinesias. Co-administration of JL-18, at low doses (0.1, 0.3 mg/kg) with L-Dopa/benserazide, produced a dose-dependent reduction in L-Dopa-induced dyskinesias without a parallel return to parkinsonism. The present results suggest that novel selective dopamine D(4) receptor antagonists may represent a useful tool to reduce L-Dopa-induced dyskinesias.


Subject(s)
Clozapine/analogs & derivatives , Clozapine/pharmacology , Dyskinesia, Drug-Induced/prevention & control , Parkinsonian Disorders/drug therapy , Analysis of Variance , Animals , Antiparkinson Agents/pharmacology , Behavior, Animal/drug effects , Benserazide/pharmacology , Dose-Response Relationship, Drug , Female , Levodopa/pharmacology , Macaca fascicularis , Motor Activity/drug effects , Parkinsonian Disorders/physiopathology
18.
Naunyn Schmiedebergs Arch Pharmacol ; 361(2): 181-6, 2000 Feb.
Article in English | MEDLINE | ID: mdl-10685874

ABSTRACT

Treatment of Parkinson's disease with L-dopa is plagued in a majority of patients by dyskinesias. Noradrenaline/dopamine interactions are proposed on behavioral, biochemical, physiological and anatomical grounds. The aim of the study was to test the potential antidyskinetic effect of the alpha2-adrenoceptor antagonist, idazoxan, in a primate model of Parkinson's disease. Six female cynomolgus monkeys previously rendered parkinsonian by the toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and presenting an unchanged syndrome for several months were used. All responded readily to L-dopa but had developed dyskinesias which were manifested with each dose. In the first part of the study, seven doses of idazoxan (ranging from 0.25 mg/kg to 10 mg/kg, p.o.) were administered together with the vehicle or in combination with a fixed dose of L-dopa/benserazide (100/25 mg, p.o.). In the second part of the study, a fixed dose of idazoxan (7.5 mg/kg) was administered daily for 10 days and L-dopa was added to idazoxan on days 1, 4, 7 and 10. Vehicle (empty capsule) was used as control. Idazoxan, by itself (ranging from 5 mg/kg to 10 mg/kg), increased locomotor activity and improved the disability score with virtually no dyskinesias in three animals. In combination with L-dopa, idazoxan did not impair the antiparkinsonian response but significantly reduced dyskinesias in all six animals up to 65% at doses of 7.5 mg/kg and 10 mg/kg and delayed their onset, so that the "ON" state without dyskinesias was prolonged. The antidyskinetic effect of idazoxan was maintained when repeatedly administered for 10 days. On day 10, the locomotor response to L-dopa was significantly potentiated by chronic administration of idazoxan. Our results indicate that idazoxan has some antiparkinsonian effect of its own and may constitute a useful adjunct to L-dopa as it can reduce dyskinesias without impairing the relief of symptoms, this effect being maintained over time in this model.


Subject(s)
Adrenergic alpha-2 Receptor Antagonists , Adrenergic alpha-Antagonists/therapeutic use , Antiparkinson Agents/therapeutic use , Dyskinesia, Drug-Induced/prevention & control , Idazoxan/therapeutic use , Levodopa/toxicity , Parkinson Disease/drug therapy , Animals , Dose-Response Relationship, Drug , Female , MPTP Poisoning/drug therapy , Macaca fascicularis , Motor Activity/drug effects , Norepinephrine/physiology , gamma-Aminobutyric Acid/metabolism
19.
Clin Neuropharmacol ; 22(5): 281-7, 1999.
Article in English | MEDLINE | ID: mdl-10516879

ABSTRACT

We assessed the antiparkinsonian response in MPTP-treated monkeys after acute or repeated treatment with oral L-Dopa, subcutaneous administration of L-Dopa methyl ester (LDME) or apomorphine, alone and in combination with D1 antagonists SCH 23390 (SCH) or NNC 01-0112 (NNC). When given alone, the L-Dopa effect occurred within the first hour after treatment. Coadministration of SCH or NNC with L-Dopa significantly delayed the onset of action. The response duration remained unchanged, as did the extent of the antiparkinsonian effect, after SCH, whereas the former became shorter at the higher doses of NNC tested. Bypass of the gastrointestinal tract using parenteral injections of LDME and apomorphine allowed the rapid turning "on" of the animals. Both D1 antagonists administered with LDME delayed the onset and shortened the duration of the therapeutic effect as the dose increased. Pretreatment with SCH failed to block the antiparkinsonian effect induced by apomorphine, but reduced the response duration markedly in a dose-related fashion. Repeated treatment of one monkey with SCH combined with the same dopaminergic drugs produced results similar to those obtained after acute treatment in four animals. The results obtained with parenteral administration of LDME and apomorphine most probably involve pharmacodynamic actions resulting in increased threshold of response. The delay observed with L-Dopa suggests pharmacokinetic interference possibly mediated via dopamine receptors located at the level of the gut.


Subject(s)
Behavior, Animal/drug effects , Benzazepines/pharmacology , Dopamine Agents/therapeutic use , Dopamine Antagonists/pharmacology , MPTP Poisoning/drug therapy , Animals , Antiparkinson Agents/therapeutic use , Apomorphine/therapeutic use , Digestive System/drug effects , Disease Models, Animal , Dose-Response Relationship, Drug , Drug Administration Routes , Drug Interactions , Drug Therapy, Combination , Female , Levodopa/analogs & derivatives , Levodopa/therapeutic use , MPTP Poisoning/physiopathology , Macaca fascicularis , Time Factors
20.
Neurology ; 52(8): 1673-7, 1999 May 12.
Article in English | MEDLINE | ID: mdl-10331698

ABSTRACT

BACKGROUND: Chronic treatment with L-3,4-dihydroxyphenylalanine (L-dopa) is often associated with motor side effects in PD patients. The search for new therapeutic approaches has led to study the role of other neuromodulators including adenosine. Among the four adenosine receptors characterized so far, the A2A subtype is distinctively present on striatopallidal output neurons containing enkephalin and mainly bearing dopamine (DA) D2 receptors (indirect pathway). Studies in DA-denervated rats suggest that blockade of adenosine A2A receptors might be used in PD. OBJECTIVE: To evaluate the antiparkinsonian effect of a new selective adenosine A2A receptor antagonist, KW-6002, in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkeys. METHODS: In the present study, we used six MPTP-exposed cynomolgus monkeys already primed and exhibiting L-dopa-induced dyskinesias to evaluate both the antiparkinsonian and dyskinetic effect upon challenge with two oral doses (60 and 90 mg/kg) of KW-6002 administered alone or in combination with L-dopa/benserazide (50/12.5 mg). RESULTS: KW-6002 administered alone produced a dose-dependent antiparkinsonian response that reached the level of efficacy of L-dopa/benserazide but was less likely to reproduce dyskinesias in these animals. When co-administered, KW-6002 potentiated the effects of L-dopa/benserazide on motor activity (up to 30%) without affecting the dyskinetic response. CONCLUSION: Adenosine A2A receptor antagonists have antiparkinsonian effects of their own with a reduced propensity to elicit dyskinesias. They might therefore be useful agents in the treatment of PD.


Subject(s)
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/adverse effects , Levodopa/pharmacology , Parkinson Disease, Secondary/chemically induced , Purinergic P1 Receptor Antagonists , Purines/pharmacology , Animals , Brain/drug effects , Female , Levodopa/therapeutic use , Locomotion/drug effects , Macaca fascicularis , Parkinson Disease, Secondary/drug therapy , Purines/therapeutic use , Receptor, Adenosine A2A
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