Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fluctuations in performance in patients with Parkinson's disease on chronic levodopa therapy (the "on-off" effect) are due to several factors. The increasing severity during treatment of early morning akinesia, "freezing" episodes, and end-of-dose deterioration are probably due to progression of the underlying disease. Peak-dose dyskinesia and peak-dose akinesia are due to levodopa over dosage. "Yo-yo-ing", which is the severest form of such fluctuation in mobility and dyskinesias, may represent the sum of these disorders.
 ...
PMID:"On-off" effects in patients with Parkinson's disease on chronic levodopa therapy. 5 99

In a double-blind crossover trial, (-)-deprenyl, a fast-acting selective monoamine-oxidase-B inhibitor without a "cheese effect", was given to 41 patients with idiopathic Parkinson's disease who were receiving maximum tolerated doses of levodopa either alone or combined with carbidopa ("Sinemet"). In a dose of 10 mg, daily or on alternate days, (-)-deprenyl prolonged the therapeutic effect of levodopa and was effective in mild "on-off" disabilities with end-of-dose akinesia; the majority of patients with nocturnal and early-morning akinesia also improved. No statistically significant improvement occurred in diurnal akinesia, and there was no improvement in patients with severe on-off disabilities with freezing and rapid oscillations ("yo-yo" effect). Levodopa-induced dyskinesias were aggravated in 14 patients. In 5 previously untreated patients, (-)-deprenyl alone gave no benefit, but when it was used with levodopa and carbidopa a mean dosage reduction of 200 mg levodopa daily was possible. Depression, present in 15 patients, was unchanged. (-)-Deprenyl in combination with smaller total daily doses of levodopa and a peripheral decarboxylase inhibitor may prove useful in reducing the frequency and severity of some types of on-off effect with overall benefit comparable to that obtained with larger doses of levodopa.
 ...
PMID:Deprenyl in Parkinson's disease. 7 2

N-carbamoyl-2-(2,6-dichlorophenyl) acetamidine hydrochloride (LON 954) causes a reproducible rest tremor in mice, of rapid onset and short duration with no associated rigidity or akinesia and in the absence of any marked changes in body temperature or accompanying peripheral parasympathomimetic effects. This tremor can be antagonised by the dopamine receptor agonists L-Dopa, bromocriptine, nomifensine and piribedil, as well as by anticholinergic anti-Parkinson drugs having an inhibitory effect on dopamine uptake such as benapryzine and benztropine. In contrast, benzhexol, orphenadrine and amantadine had no effect. LON 954 appears to be more specific than oxotremorine for the detection of drugs having therapeutic potential in the treatment of Parkinson's disease, particularly those exerting their effect through dopaminergic systems. An antagonist (BS 100-141), which is a structural isomer of LON 954, is also described.
 ...
PMID:The production of an alternative laboratory model of the Parkinson syndrome using a new benzylimidoylurea derivative LON 954. 40

Tiapride, a substituted benzamide derivative closely related to metoclopramide, reduced levodopa-induced peak dose involuntary movements in 16 patients with idiopathic Parkinson's disease. However, an unacceptable increase in disability from Parkinsonism with aggravation of end-of-dose akinesia led to its cessation in 14 patients. Tiapride had no effect on levodopa-induced early morning of "off-period" segmental dystonia. These results fail to support the notion that levodopa-induced dyskinesias are caused by overstimulation of a separate group of dopamine receptors.
 ...
PMID:Tiapride in levodopa-induced involuntary movements. 45 86

Patients with Parkinson's disease performed several different stereotyped elbow flexion tasks, and the electromyographic (EMG) patterns from biceps and triceps were compared with previously established normal standards. The EMG pattern during a smooth flexion task was almost always abnormal and was characterized by alternating activity in biceps and triceps. The EMG patterns during a fast flexion task were also usually abnormal although they were always composed of bursts of EMG activity of normal duration appearing alternately in the agonist and antagonist muscles. These bursts, associated with movements of the limb, have a superficially similar appearance to the EMG bursts seen with tremor-at-rest, but certain physiological differences are demonstrated. This study demonstrates that both slow (ramp) and fast (ballistic) movements are clearly abnormal in these patients with disease of the basal ganglia. In a task designed to investigate antagonist inhibition before agonist activity, a majority of the patients performed normally. This suggests that, contrary to previous claims, slowness of movement (akinesia/bradykinesia) is not due either to failure to relax or to rigidity of antagonist muscle.
 ...
PMID:Analysis of stereotyped voluntary movements at the elbow in patients with Parkinson's disease. 59 80

Twenty-six patients affected by Parkinson's disease were treated with a 2-Br-alpha-ergocriptine (CB 154): 14 cases were given CB 154 alone, and 12 were given CB 154 along with L-dopa plus benserazide (Madopar). Both CB 154 and combined therapy (CB 154+Madopar) induced a significant improvement in total disability score, tremor, rigidity, akinesia, self-sufficiency, and some motor performance tests (dynamic tests). No significant difference was found between results obtained with CB 154 therapy and with Madopar treatment, while the improvement induced by combined therapy (CB 154+Madopar) was significantly higher than that obtained by Madopar alone. The averse reactions caused by CB 154 alone or associated with Madopar are similar to those observed during other dopaminergic treatment. CB 154 alone or combined with Madopar appears to be a useful advance in the management of Parkinson's disease.
 ...
PMID:Bromocriptine alone or associated with L-dopa plus benserazide in Parkinson's disease. 59 82

Before and during a standardized course of trifluoperazine therapy, 18 schizophrenic patients underwent repeated examinations for extrapyramidal motor signs, clinical psychopathology, and urinary excretion of free and conjugated forms of dopamine and its metabolites. Patients excreting more free dopamine and metabolites, or showing less complete conjugation, before drug treatment, were much less likely than others to develop parkinsonian akinesia and rigidity during drug treatment. Neither catatonic rigidity nor akinesia before treatment was predictive of a parkinsonian response to trifluoperazine, but pretreatment tremor may have been. The severity of schizophrenic psychopathology was unrelated to dopamine excretion. This study of schizophrenic patients, and our previous research in Parkinson's disease, suggest that urinary dopamine excretion may reflect dopaminergic function of the extrapyramidal motor system in both conditions.
 ...
PMID:Dopamine excretion and vulnerability to drug-induced Parkinsonism. Schizophrenic patients. 61 44

It has been suggested that patients with Parkinson disease partially compensate for neuron loss by developing denervation supersensitivity, and, if so, that prolonged levodopa (L-dopa) therapy might lead to desensitization. As a preliminary test of this hypothesis, and in order to study whether it was possible to "resensitize" a patient who had already presumably been desensitized by previous L-dopa therapy, a patient who had become unpredictably responsive to L-dopa was investigated. The patient had been taking L-dopa for eight years and had exhibited severe dyskinesia-akinesia oscillation ("on-off" phenomenon) before the study. There was no consistent response to his hourly doses of Prolopa (L-dopa and benserazide in a 4:1 ratio). He was first lowered, over 33 days, to 20% of his original Prolopa dose. The dosage was then increased until a consistent response was observed. The three main results achieved were, first, overall reduction by 64% of the daily requirement for L-dopa; second, conversion from a previously unpredictable to a predictable response to each dose of L-dopa; and, third, change in his movement fluctuations to a pattern more typical of "end-of-dose" akinesia than the "on-off" phenomenon. The results support the idea of dopamine receptor resensitization upon reduction of the L-dopa dosage.
 ...
PMID:The L-dopa on-off effect in Parkinson disease: treatment by transient drug withdrawal and dopamine receptor resensitization. 74 58

Thirty-one patients with Parkinson's disease were treated with the ergot alkaloid bromocriptine, a drug which stimulates dopamine receptors. Bromocriptine had a slight therapeutic effect in patients on no other treatment and an additional effect in patients on levodopa. The mean optimum dosage of bromocriptine, established over a 12 week period, was 26 mg daily. In 20 patients bromocriptine was compared with placebo in a double-blind controlled trial. Active treatment caused a significant (P less than 0.02) reduction in total disability and akinesia scores. The least disabled patients showed the greatest response. Side-effects of bromocriptine--nausea, vomiting, hallucinations, and abnormal involuntary movements--were similar to nature to those of levodopa. In most normal subjects, bromocriptine causes an increase in plasma growth hormone concentration. This was determined in 20 patients with Parkinson's disease after 1-15 mg bromocriptine. Only a single patient showed an obvious increase up to 120 minutes after dosage. Bromocriptine was not effective treatment in two patients who had not previously responded to levodopa and replacement of this drug by bromocriptine in patients with end-of-dose akinesia after chronic levodopa treatment did not totally abolish response swings.
 ...
PMID:Bromocriptine treatment in Parkinson's disease. 77 75

In Parkinson's disease there is a derangement of the metabolism of at least 3 major brain monoamines, namely, dopamine (DA), norepinephrine (NE) and serotonin (5-HT). Of these alterations the severe deficiency of DA in the striatum is most characteristic, being (a) found in Parkinsonian syndromes of any etiology and (b) significantly correlated with the degree of cell loss in the substantia nigra, and the severity of the main symptoms. On the basis of neurochemical-clinical correlations Parkinson's disease may be subdivided into (a) an asymptomatic stage during which the striatal DA deficiency may reach a marked degree but can be compensated by the remaining DA neurons, and (b) the stage of decompensation (i.e. clinically manifest disease) which ensues when the depetion of striatal DA reaches 70% or more. L-Dopa's main feature as a specific antiparkinson drug may be seen in its potential to revert the decompensated stage of the disease to the stage of functional compensation. This is in many cases possible because (a) the DA turnover in the remaining DA neurons is increased, providing for a high rate of formation (from L-dopa) and release of DA; (b) the "denervated" striatal receptors are supersensitive to DA; and (c) the newly-formed DA can be expected to reach a wide area of the striatum due to the high degree of divergence of the dopaminergic innervation. Compared with the striatal DA deficiency, the degree of NE and 5-HT decrease in the Parkinsonian brain is moderate. The decrease in NE may be due to the (moderate) cell loss in the locus coeruleus; at present no morphological basis for the lowering of brain 5-HT is known. The functional significance of the changes in brain NE may be an aggravation of akinesia. The decrease in brain 5-HT may be related to aspects of Parkinson's disease in turn related to affective behavior and mood.
 ...
PMID:Brain monoamines and parkinsonism. 78 96


1 2 3 4 5 6 7 8 9 10 Next >>