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Biomedical subjects

D Chadwick

Publications and source records attributed to D Chadwick.

At least 145 records · Page 8Linked to original sources

Reticular reflex myoclonus: a physiological type of human post-hypoxic myoclonus.

A patient with post-hypoxic myoclonus, sensitive to therapy with 5-hydroxytryptophan and clonazepam, was subjected to detailed electrophysiological investigation. Brief generalised jerks followed the critical stimulus of muscle stretch. The electroencephalogram showed generalised spikes that were associated with, but not time locked to, the myoclonus. The cranial nerve nuclei were activated upward. Analysis of the findings suggests that the mechanism of the myoclonus is hyperactivity of a reflex mediated in the reticular formation of the medulla oblongata.

5-Hydroxytryptophan↗

One drug (phenytoin) in the treatment of epilepsy.

Thirty-one, previously untreated, adult outpatients with idiopathic or focal grand-mal and/or focal minor seizures were treated initially with phenytoin. Serum-phenytoin concentrations were monitored to achieve an optimum range of 10-20 mug/ml if necessary. With a mean duration of follow-up of 14-7 months, only three (10%) patients have required the addition of a second drug, although without the guidance of serum concentrations sixteen (54%) might have been treated with a further drug. In the optimum serum-phenytoin range only 1 grand-mal attack occurred in this series, compared with a mean pre-treatment grand-mal seizure-rate of 1-1/month. Serum phenytoin declined slowly in fourteen (45%) patients. These observations suggest that many epileptic patients could be satisfactorily treated with one drug instead of the polypharmacy which they usually receive.

Adolescent↗

Anticonvulsant-induced dyskinesias: a comparison with dyskinesias induced by neuroleptics.

Anticonvulsants cause dyskinesias more commonly than has been appreciated. Diphenylhydantoin (DPH), carbamazepine, primidone, and phenobarbitone may cause asterixis. DPH, but not other anticonvulsants, may cause orofacial dyskinesias, limb chorea, and dystonia in intoxicated patients. These dyskinesias are similar to those caused by neuroleptic drugs and may be related to dopamine antagonistic properties possessed by DPH.

Adolescent↗

Manipulation of brain serotonin in the treatment of myoclonus.

The response of myoclonus to oral and intravenous L-5-hydroxytryptophan (5-H.T.P.) in combination with a peripheral decarboxylase inhibitor (carbidopa) and to clonazepam has been examined in 9 patients. Moderate improvement or complete cessation of myoclonus followed treatment with one or both of these regimens in 5 patients, 1 of whom also responded to the concurrent administration of L-tryptophan and a monoamineoxidase inhibitor. The remaining 4 patients were at best only slightly improved by either 5-H.T.P. or clonazepam. The responsive group consisted of 3 patients with a history of anoxia, 1 patient with non-history of severe head injury, and 1 patient with non-progressive focal myoclonus and epilepsy. This group had low levels of 5-hydroxyindole acetic acid in the lumbar cerebrospinal fluid. It is suggested that 5-H.T.P. plus carbidopa, L-tryptophan plus a monoamine-oxidase inhibitor, and clonazepam may all act by elevating brain levels of serotonin (5-H.T.) and that some human myoclonic syndromes may be specifically related to a cerebral deficiency of 5-H.T.

5-Hydroxytryptophan↗

Amines, anticonvulsants, and epilepsy.

Concentrations of 5-hydroxyindoleacetic acid (5-H.I.A.T.) in cerebrospinal fluid (C.S.F.) were significantly raised in twenty-seven anticonvulsant-treated epileptic patients compared with fifteen untreated epileptics and twenty-two neurological controls. This rise was not seen until therapeutic blood-levels of phenobarbitone and diphenylhydantoin had been achieved, and was most striking in clinically intoxicated patients. Similar trends were seen in C.S.F. homovanillic acid (H.V.A). There was a close correlation between C.S.F. 5-H.I.A.A. and H.V.A., especially in the treated epileptics. These findings have implications for the antiepileptic and toxic effects of anticonvulsant drugs.

Adolescent↗

Folate and monoamine metabolism in epilepsy.

In 27 drug-treated epileptics there was a significant fall in serum, red cell and CSF folate levels compared with 15 untreated epileptics and 22 neurological controls. The 3 folate parameters were positively correlated with each other and negatively correlated with serum phenobarbitone, diphenylhydantoin and primidone. There was also a significant elevation of CSF 5-hydroxyindoleacetic acid (5HIAA) in the drug-treated epileptics; but this was not seen until "therapeutic" serum levels of phenobarbitone and diphenylhydantoin had been achieved and was most marked in clinically intoxicated patients. Similar trends were observed in CSF homovanillic acid (HVA). CSF 5HIAA and HVA were positively correlated with each other, especially in the drug-treated patients, in whom both amine metabolites were also negatively correlated with CSF folate. A possible relationship between folate and monoamine metabolism is discussed with particular reference to the antiepileptic and toxic effects of phenobarbitone, diphenylhydantoin and primidone.

Adolescent↗

Medical diagnosis of the sexually abused child.

This article reviews what has been learned in the last two decades about the medical diagnosis of child sexual abuse. Studies indicate that a normal physical exam is common in sexual abuse victims, that healing of injuries due to abuse is rapid and sometimes complete, that a minority of victims seen for abuse are boys, that nonsexual transmission of sexually transmitted diseases is rare, and that congenital and acquired conditions may mimic physical findings caused by sexual abuse. The article summarizes clinical research on physical findings in nonabused children, abused children, and abused children with independent confirmation of abuse. A classification of physical findings is proposed along a continuum of certainty that sexual abuse has occurred. The child's history is essential in the accurate diagnosis of most cases of sexual abuse.

Adolescent↗

Growth hormone response to diazepam, clonidine and glucagon in patients with epilepsy.

The differing actions of phenytoin, carbamazepine and sodium valproate on growth hormone release were studied in 20 patients with recently diagnosed epilepsy using diazepam, clonidine and glucagon as stimulatory tests of growth hormone response. The results are compared with the growth hormone response obtained pre treatment, and those from 20 control patients and 11 patients with chronic treated epilepsy. There was a reduction in growth hormone response to diazepam in both treated and untreated patients with epilepsy compared to controls. Treatment with phenytoin resulted in a significant increase in growth hormone release after diazepam and glucagon, whilst sodium valproate reduced the growth hormone response to diazepam.

Adult↗