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Biomedical subjects

C J Earl

Publications and source records attributed to C J Earl.

8 recordsLinked to original sources
PubMed1979

Niacin depletion in Parkinsonian patients treated with L-dopa, benserazide and carbidopa.

1. Benserazide and carbidopa, decarboxylase inhibitors used in the treatment of Parkinson's disease, have been shown to inhibit the enzyme kynurenine hydrolase in rat and mouse liver. This results in reduced synthesis of nicotinamide coenzymes from tryptophan, and hence an increased reliance on dietary niacin. 2. Pellagra might be expected as a result of this inhibition of endogenous synthesis of nicotinamide nucleotides, but has not been reported in patients treated with either drug. 3. The urinary excretion of N1-methyl-nicotinamide, a product of nicotinamide nucleotide metabolism, is considerably reduced in patients treated with dopa alone or in combination with an inhibitor of peripheral dopa decarboxylase, to as low as 40% of the control value. This means that many of these patients could be classified as 'at risk' of niacin deficiency, even if not frankly deficient. 4. Patients treated with dopa plus a decarboxylase inhibitor, but not those treated with dopa alone, also show a reduced excretion of xanthurenic acid, and an increased excretion of kynurenine, as would be expected after inhibition of the kynurenine pathway, and possibly indicative of marginal vitamin B6 deficiency.

Adolescent↗
PubMed1978

Factors influencing the risk of multiple sclerosis developing in patients with optic neuritis.

One-hundred and forty-six patients who had presented with optic neuritis but without evidence of demyelination elsewhere in the nervous system, and in whom no specific cause could be identified, were reassessed clinically between one month and twenty-three years after the onset. Fifty-eight patients (40 per cent) had developed MS. All 146 patients were HLA-typed. Three factors were identified which were significantly associated with the development of MS: positive typing for the HLA antigen BT 101, winter onset of the initial attack of optic neuritis in BT 101-positive patients only, and recurrent attacks of optic neuritis. The application of these results to the individual patient is of limited use. However, recurrent attacks of optic neuritis should be given the same significance in the clinical classification of MS as episodes of demyelination occurring elsewhere in the central nervous system in a patient with a previous attack of optic neuritis. The results suggest that optic neuritis is caused by two different environmental agents or groups of agents and that the agent which is most common in the winter leads to the development of MS in the genetically susceptible individual. The agent more common in the summer is much less likely to cause MS in either suscetible or non-susceptible individuals. The biological role of the HLA system in the handling of foreign antigens is discussed and it is suggested that the presence of the HLA antigens associated with MS confers a specific disadvantage on individuals in the ability to handle infection by the MS causative agent and that this allows damaging immunological processes to develop.

Diagnosis, Differential↗
PubMed1977

Gold encephalopathy.

Encephalopathy is described developing in a 42 year old man who was receiving gold treatment for rheumatoid arthritis.

Adult↗
PubMed1975

Tolosa-Hunt syndrome. The dangers of an eponym.

Two cases of painful ophthalmoplegia are described which were initially thought to be examples of the Tolosa-Hunt syndrome. Both were partially responsive to steroid treatment. Subsequent investigations showed that in one case the condition was due to an aneurysm and in the other to a malignant lymphoma.

Aneurysm↗
PubMed1975

Flaccid paraplegia: a feature of spinal cord lesions in Holmes-Adie syndrome and tabes dorsalis.

In a patient with Holmes-Adie syndrome, and in another with tabes dorsalis, a transverse cord lesion resulted in a severe, but flaccid paraplegia with absent tendon reflexes. Flexor spasms were severe in both patients, but spasticity was absent. The significance of these observations is discussed in relation to the functional and anatomical disorder in these two syndromes.

Adie Syndrome↗