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Biomedical subjects

D B Calne

Publications and source records attributed to D B Calne.

At least 253 records · Page 14Linked to original sources

Comparison between lergotrile and bromocriptine in parkinsonism.

The therapeutic and adverse effects of two ergot derivatives, bromocriptine and lergotrile, were compared in idiopathic parkinsonism. At both low (50 mg daily) and high (150 mg daily) dosage there was a similar but not identical profile of response. Initially, lergotrile tended to induce more severe but always transient hypotension. At higher doses, bromocriptine caused more dyskinesia. Neurological deficits improved with increasing doses up to an average daily level of 80 to 150 mg of ergot derivatives combined with levodopa, 450 to 1,150 mg, and carbidopa, 45 to 115 mg. However, efficacy often declined at the highest doses of antiparkinsonian agents. Adverse effects caused by ergot derivatives are more common with dosages greater than 100 mg per day. In general, the best overall therapeutic results with bromocriptine and lergotrile were obtained in the dose range of 50 to 100 mg daily for each. It is concluded that bromocriptine and lergotrile are similar in their therapeutic properties and that both are comparable in efficacy to levodopa plus carbidopa (though optimal results are commonly obtained by combining submaximal doses of levodopa with ergot derivatives). The role for each drug in the treatment of parkinsonism is likely to be determined by factors such as cost (bromocriptine) and hepatotoxicity (lergotrile).

Acetonitriles↗

Parkinsonism. Clinical and neuropharmacologic aspects.

While the etiology of the most common form of parkinsonism (idiopathic) remains elusive, studies of the regional biochemistry and pharmacology of the brain have led to recognition of the importance of certain pathways, such as the nigrostriatal system. This information evolved from the discovery that the neurotransmitter dopamine is depleted in parkinsonism and that restoration of dopamine by administration of its precursor, levodopa, induces a dramatic therapeutic response in many patients. Such studies have initiated and sustained a major surge in neuropharmacologic advances, but the tangible benefits, in the form of therapeutic results, have undergone some critical reappraisal with the appearance of late adverse reactions to levodopa. One practical approach to this problem is deliberate delay in starting levodopa therapy and the use of lower doses. Use of artificial dopaminergic agonists and selective inhibitors of monoamine oxidase B has also been investigated.

Animals↗

Treatment of parkinsonism.

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Aromatic Amino Acid Decarboxylase Inhibitors↗

Experiences with a new ergoline (CF 25-397) in parkinsonism.

Studies on rats with unilateral nigral lesions suggest that a new ergoline, CF 25-397, is a dopaminergic agonist that might improve parkinsonism. CF 25-397 induces less stereotyped behavior than other dopaminergic agents in rats, and might therefore cause less dyskinesia than levodopa in man. We investigated the clinical actions of CF 25-397 in nine patients. During treatment, severe deterioration resulted in hypokinesia and rigidity; five patients showed marked dysphagia and dysphonia. There was statistically significant deterioration in four timed tests. Mild improvement, not statistically significant, was noted in tremor. These results indicate that clinical implication of the response to potential therapeutic agents in rodent models of parkinsonism must be interpreted with caution.

Aged↗

Antiparkinsonian therapy.

Powerful new tools for the treatment of parkinsonism include levodopa, decarboxylase inhibitors, and dopaminergic agonists. Yet earlier drugs still have a useful role to play. The decision to begin pharmacotherapy must be adjusted individually for each patient.

Antiparkinson Agents↗

Bromocriptine and levodopa (with or without carbidopa) in parkinsonism.

Bromocriptine, a dopamine receptor agonist, was administered to 20 patients with idiopathic parkinsonism taking levodopa (L-dopa) or "Sinemet" (levodopa combined with carbidopa in a 10/1 ratio) at optimum doses. In a double-blind randomised cross-over study lasting 6 months, the addition of bromocriptine (mean daily dose 79 mg) led to a significant (P less than 0.01) 74% reduction in the dose of sinemet and levodopa. "Total disability score" showed a significant (P less than 0.01) improvement at both low and high doses of bromocriptine. Tremor improved 50% (P less than 0.01), with significant improvements in gait, posture, writing, balance, rigidity, finger dexterity, and drooling. Adverse reactions were similar to those observed with sinemet and levodopa. Although both the cause and the cure of idiopathic parkinsonism remain elusive, bromocriptine appears to represent a therapeutic advance.

Aged↗

Bromocriptine in Huntington chorea.

Following a recent report that apomorphine hydrochloride alleviates the involuntary movements of Huntington chorea, we have investigated another dopamine receptor agonist, bromocriptine, in this disease. A double-blind crossover study in six patients showed that rather than improving chorea, bromocriptine induced an exacerbation. This finding supports the view that choreatic movements correlate with overactivity in dopaminergic systems.

Adult↗

The encephalopathic action of five-carbon-atom fatty acids in the rabbit.

1. Five-carbon-atom organic acids (C-5 acids) have been administered intravenously to rabbits with ventriculocisternal perfusion and continuous electroencephalographic recording (EEG). The concentration of the acids in the cerebrospinal fluid (CSF) perfusate have been compared with changes in integrated low-frequency activity in the EEG. 2. The C-5 acids investigated were those accumulating in inborn errors of metabolism, i.e. isovaleric acid, beta-methylcrotonic acid, tiglic acid and alpha-keto- and alpha-hydroxy-isovaleric acid. There activity was compared with that of valeric acid. 3. Valeric acid and isovaleric acid produced coma and pronounced increase in slow-wave electrical activity and these changes paralleled the increase in concentration of the acids in the CSF perfusate. 4. The concentration of beta-methylcrotonic acid and tiglic acid in the CSF perfusate reached values comparable with valeric acid and isovaleric acid but showed less encephalopathic activity. An interaction between beta-methylcrotonic acid and isovaleric acid was observed. 5. Although the concentrations of alpha-ketoisovaleric acid and alpha-hydroxyisovaleric acid rose to the lesser extent in the CSF perfusate, changes in rousability of the animal and in the EEG recording were demonstrated. 6. It is concluded that all the C-5 acids tested have encephalopathic activity although this is lessened by the presence of either a double bond or an oxygenated functional group.

Animals↗

Nomifensine in parkinsonism.

Nomifensine, a tetrahydroisoquinolone antidepressant which facilitates dopaminergic and noradrenergic transmission, was studied in 28 Parkinsonism patients most of whom were also receiving conventional medications. Double-blind evaluations revealed a moderate therapeutic action at a mean dose level of 150 mg daily. Adverse reactions were encountered, similar to those identical by levodopa.

Aged↗