Search PubMed⌕ Search

Biomedical subjects

D B Calne

Publications and source records attributed to D B Calne.

At least 289 records · Page 16Linked to original sources
PubMed1974

Motor nerve conduction velocity in peroneal muscular atrophy: evidence for genetic heterogeneity.

Measurements of motor nerve conduction velocity are reported in 88 subjects from 20 families in which a clinical diagnosis of peroneal muscular atrophy had been made in the index cases. The values display a bimodal distribution. The majority of cases show a substantially reduced conduction velocity, a smaller group displaying velocities within the normal range or only slightly decreased. This difference was demonstrated to have a genetic basis.

Adolescent↗
PubMed1973

"On-off" phenomena related to high plasma levodopa.

The neurological deficit and plasma concentrations of levodopa have been studied in a Parkinsonian patient experiencing "on-off" phenomena. Blind evaluations of transient attacks of dysphonia revealed an association between episodes of neurological deterioration and exceptionally high plasma concentrations of levodopa shortly after ingestion. These results indicate that "on-off" phenomena can be toxic reactions to levodopa rather than deteriorations due to inadequate intake or absorption of the drug. Management of patients subject to such attacks should be aimed at minimizing fluctuations in the serum level of the drug.

Aged↗
PubMed1973

Actions of levodopa on the blood pressure of conscious rabbits.

1. In conscious rabbits, the rapid intravenous injection of levodopa alone does not have any significant effects on the blood pressure in doses up to 10 mg/kg.2. After inhibition of monoamine oxidase, levodopa induces a sustained pressor response.3. This response can be blocked by inhibition of extracerebral decarboxylase.4. Possible mechanisms for these interactions are discussed, together with their therapeutic implications in Parkinsonism.

Animals↗
PubMed1972

Action of L- -methyldopa-hydrazine on the blood pressure of patients receiving levodopa.

The blood pressure and pulse rate have been compared in a 'double blind, cross over' study involving twenty patients with idiopathic Parkinsonism receiving maximum tolerated dosage of levodopa with and without an extracerebral decarboxylase inhibitor, L-alpha-methyldopahydrazine. The supine and erect systolic pressures were significantly higher and the erect pulse rate significantly lower during administration of L-alpha-methyldopahydrazine. The implications of these observations are discussed.

Adult↗
PubMed1972

X-linked scapuloperoneal syndrome.

Observations are presented on a family with muscular weakness and wasting with an onset in childhood, predominantly affecting the proximal muscles in the upper limbs and the distal muscles in the lower. This was accompanied by contractures of the elbows and by pes cavus. Pseudohypertrophy was absent. Progression was slow, but an associated cardiomyopathy developed in adult life. Investigations favoured a myopathic basis. The inheritance was of X-linked recessive pattern and the disorder was linked with deutan colour blindness. The clinical features in this family appear to be distinctive and it is likely that the disorder represents a separate clinical entity.

Adolescent↗
PubMed1971

Idiopathic Parkinsonism treated with an extracerebral decarboxylase inhibitor in combination with levodopa.

The clinical actions of levodopa in Parkinsonism, given with and without an extracerebral decarboxylase in hibitor, L-alpha-methyldopahydrazine, were compared. Twenty-one patients were investigated in a "double-blind cross-over" study, administering levodopa in maximum tolerated dosage. L-Alpha-methyldopahydrazine failed to augment the overall therapeutic actions of levodopa but it consistently alleviated nausea. It is concluded that L-alpha-methyldopahydrazine will prove useful in the management of some Parkinsonian patients who have difficulty in taking levodopa alone.

Adult↗
PubMed1971

Action of thymoxamine on mydriasis induced by levodopa and dopamine.

Eye-drops of levodopa and dopamine induce pupillary dilatation which is inhibited by thymoxamine, an alpha-adrenergic blocking drug. This indicates that the mydriatic action of levodopa and dopamine involves excitation of alpha-adrenergic receptors of the dilator pupillae muscle. Such a conclusion is in accord with the previously expressed suggestion that levodopa is rapidly converted to dopamine, which displaces noradrenaline from adrenergic nerve endings.The findings that dopamine exerts alpha-adrenergic effects at the periphery may be construed as evidence in support of the view that the hypotensive action of levodopa is mediated via the central nervous system.

Adrenergic alpha-Antagonists↗