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Biomedical subjects

R J Abbott

Publications and source records attributed to R J Abbott.

65 records · Page 4Linked to original sources

Central and peripheral nerve conduction in thyroid dysfunction: the influence of L-thyroxine therapy compared with warming upon the conduction abnormalities of primary hypothyroidism.

1. The latencies of the visual evoked responses, indices of central nerve conduction, and peripheral nerve conduction were slowed in patients with primary hypothyroidism compared with controls. 2. In thyrotoxic patients, there was no change in the latencies of the visual evoked responses and peripheral nerve conduction compared with the control group. 3. The abnormalities seen in hypothyroidism were reversed by L-thyroxine therapy. 4. Warming untreated hypothyroid patients significantly improved both central and peripheral nerve conduction. 5. The conduction delay found in hypothyroidism is to a large extent dependent upon a subnormal body temperature.

Evoked Potentials, Visual↗

CSF and plasma GABA levels in Parkinson's disease.

CSF gamma-aminobutyric acid (GABA) levels were reduced in patients with idiopathic Parkinson's disease when compared with age matched controls, but the difference was not significant. However, when the Parkinsonian patients were subdivided, CSF GABA levels were lower in the levodopa treated group than in the untreated group and the controls. There was no difference in plasma GABA levels between Parkinsonian patients and controls.

Adult↗

Effect of freezing on gamma-aminobutyric acid levels in human cerebrospinal fluid.

Using a radioreceptor assay, the concentration of gamma-aminobutyric acid (GABA) in human cerebrospinal fluid (CSF) was found to be elevated significantly following a single deep-freeze to --70 degrees C and thaw. Mean CSF GABA (+/- SD) in unfrozen CSF was 173 +/0 73 pmol/ml (n = 24). After a single deep-freeze, the mean level was 243 +/- 106 pmol/ml (p less than 0.02). Subsequent freeze-thaw cycles resulted in further irregular and unpredictable elevations in CSF GABA. Mean level after two freezes was 379 +/- 125 pmol/ml and after three freezes 654 +/- 411 pmol/ml. These changes could result in the incorrect interpretation of results in patients suffering from neurological diseases.

Adult↗

Peripheral nerve function in patients with bronchial carcinoma. Comparison with matched controls and effects of treatment.

Clinical examination of 80 patients with bronchial carcinoma showed minor neurological abnormalities but in only a few cases were these considered to be due to neuromyopathy. Spontaneous activity in the EMG was shown in 35%, consistent with a mild degree of partial denervation; when 50 of the patients were matched with 50 controls the patients showed a small but significant impairment of nerve conduction velocity in comparison with the controls. These findings accord with subclinical neuropathy in a high proportion of patients with bronchial carcinoma consistent with primary axonal change. Thirty patients participated in a prospective study of the effects of treatment. Of these nine were reassessed following surgery or radiotherapy. Although there was a trend towards improvement in sensory conduction there was no consistent change in the electromyographic findings.

Bronchial Neoplasms↗

Serum prolactin and cortisol concentrations after grand mal seizures.

Serial serum prolactin and cortisol levels were measured in five patients after a grand mal seizure and in four volunteers with simulated seizures. Single levels were measured after a witnessed seizure in 26 patients and in a matched control group. Significant increase in both prolactin and cortisol levels occurred after seizures. The change in cortisol level may reflect a non-specific stress response, but the increase in prolactin levels could not be accounted for on this basis, and probably indicates an alteration in hypothalamic neurotransmitter activity during the seizure. These findings may have clinical value in the diagnosis of epilepsy.

Adult↗

A placebo-controlled evaluation of ropinirole, a novel D2 agonist, as sole dopaminergic therapy in Parkinson's disease.

The efficacy and safety of ropinirole, a novel nonergot dopamine D2-like receptor agonist, was assessed as monotherapy for the treatment of patients with early-stage Parkinson's disease. In this double-blind, multicenter trial, patients were randomly allocated in a ratio of 2:1 to receive, over a 12-week period, either ropinirole or placebo. Clinical status was assessed using the Unified Parkinson's Disease Rating Scale (UP-DRS), Clinician's Global Evaluation (CGE), and a finger-tapping score. In all, 41 patients received ropinirole and 22 received placebo. The end-point analysis, on an intention-to-treat basis, revealed a significant difference (p = 0.018) in improvement in UP-DRS motor score from baseline between treatment groups (ropinirole, 43.4%; and placebo, 21.0%). Other parameters, including the number of responders and improvement in CGE, showed similar results. Three patients in the ropinirole group and one patient in the placebo group discontinued the study because of adverse events. There was no significant difference between the treatment groups in the overall incidence of adverse events. Although the dopaminergic side effects were reported significantly more frequently in the ropinirole group than in the placebo group (dizziness, p = 0.0326; nausea, p = 0.001; and somnolence, p = 0.005), none necessitated study withdrawal. There was no evidence of any chronic effect of the study medication on vital signs. In conclusion, ropinirole is a safe and well-tolerated drug and, as monotherapy, provided significant therapeutic benefit compared with placebo to patients in the early stages of Parkinson's disease.

Adult↗