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Biomedical subjects

A N Gale

Publications and source records attributed to A N Gale.

10 recordsLinked to original sources
PubMed1991

Neurology.

Explore the source record for details and available documents.

Dementia↗
PubMed1988

Dystonia in homocystinuria.

Three patients with homocystinuria due to cystathionine beta-synthase deficiency who developed progressive generalised dystonia are described. Although cerebrovascular thrombosis is usually thought to be responsible for neurological dysfunction in homocystinuric patients, neuropathological studies in one case and clinical and radiological evidence in the other two suggested that dystonia was not caused by brain infarction. Movement disorder associated with homocystinuria may result from the neurochemical changes in the basal ganglia related to the inherited defect in sulphur amino acid metabolism.

Adolescent↗
PubMed1982

Changes produced by a hypomyelinating neuropathy in muscle and its innervation. Morphological and physiological studies in the Trembler mouse.

The peripheral nerves of the Trembler mouse are hypomyelinated. The effects of the neuropathy on muscle and motor end-plate morphology, and on neuromuscular transmission in slow-twitch (soleus) and fast-twitch (extensor digitorum longus) muscle are reported. After forming normally, motor end-plates developed ultraterminal sprouts by about 18 days of age in deep, slow-twitch muscles. The only ultrastructural abnormality in muscle at this age was disruption of Z-lines. Ultraterminal sprouting progressed, and by about 3 months the innervation zone consisted of a mass of branching axons associated in places with cholinesterase activity. The ultrastructure of end-plates became abnormal. Fascicular atrophy was present in older Tremblers and the ultrastructural morphology of muscle fibres became disorganized with accumulation of subsarcolemmal granular material. Abnormal muscle fibres were innervated by axonal sprouts. The superficial, predominantly fast-twitch, muscles showed milder changes at all ages even though the nerves supplying them were hypomyelinated. Studies of neuromuscular transmission showed that soleus retained its slow-twitch and extensor digitorum longus its fast-twitch characteristics, and miniature end-plate potentials were of normal frequency and amplitude. The latency of end-plate potentials and the refractory period of transmission were prolonged in both soleus and extensor digitorum longus. With repetitive stimulation at 50 Hz a cyclical pattern of responses and failures occurred which was probably caused by intermittent conduction block along the peripheral nerve. Although the pathological changes in Trembler muscle were like those of partial denervation, atrophic muscles contained an abundance of axons and there was no evidence of axonal degeneration. The changes in muscle are therefore a consequence of hypomyelination without axonal loss. Since slow-twitch muscles are normally subjected to prolonged stimulation, failure of Trembler axons to conduct sustained trains of stimuli in vivo may contribute to the development of pathological changes in slow-twitch muscle. Hypomyelimated axons may be capable of conducting short bursts of impulses, however, which is the pattern of stimulation in fast-twitch muscle in vivo, so that fast-twitch muscle fibres and end-plates remain relatively spared.

Animals↗
PubMed1978

Neuronal ceroid-lipofuscinosis. Studies of granulocyte enzyme activities.

Neuronal ceroid-lipofuscinosis is characterized by pigmentary degeneration of the retina, psychomotor degeneration, epilepsy and intracellular deposition of ceroidlipofuscin. Recent reports have suggested that deficiency of peroxidase is the basic genetic defect. However, deficiency of myeloperoxidase could be demonstrated in some but not all patients; this deficiency was noted only when p-phenylenediamine (PPD) was used as hydrogen donor and could not be confirmed with guaiacol. We found that horseradish peroxidase (HR-P) oxidized PPD in the absence of added H2O2. The oxidative product of PPD showed the same absorption spectrum as the peroxidative product. The oxidation of PPD by HR-P was not inhibited by catalase or superoxide dismutase. In addition, catalase oxidized PPD in the presence of H2O2. Soluble and granular fractions obtained from human polymorphonuclear leukocytes (PMN) also oxidized PPD in the absence of H2O2. Addition of H2O2 inhibited the oxidation of PPD in some cell fractions. This inhibition could be partially eliminated by dialysis of the cell fractions. Thus, PPD is not a suitable hydrogen donor for the study of peroxidase. This may explain the variable results obtained by the previous investigators. In contrast, guaiacol did not show these undesirable characteristics. The PMN peroxidase (measured with guaiacol), catalase, beta-glucuronidase, acid and alkaline phosphatases were studied in individuals from three families with juvenile neuronal ceroid-lipofuscinosis. Family 1: an affected boy and healthy parents; all showed normal enzyme activities in both soluble and granular fractions. Family 2: two affected sisters, one healthy sib and mother, and Family 3: one affected boy; all showed reduced peroxidase activities in the granular fractions. Other enzymes were normal. The role of peroxidase deficiency in the pathogenesis of neuronal ceroid-lipofuscinosis is not clear. The basic defect of this syndrome remains uncertain.

Acid Phosphatase↗
PubMed1977

Familial congenital bicuspid aortic valve: secondary calcific aortic stenosis and aortic aneurysm.

A patient with an aneurysm of the ascending aorta and calcific stenosis of a congenital bicuspid aortic valve, whose brother also had a stenotic congenital bicuspid aortic valve, is described. Predominant aortic stenosis at cardiac catheterization and the presence of an aneurysm distal to and not including the aortic valvular ring made the initial diagnosis of Marfan's syndrome unlikely. Cystic medial necrosis present in the aneurysmal wall probably arose as a consequence of poststenotic dilation. Adequate noninvasive evaluation of the ascending aorta requires echocardiographic studies, as well as a chest x-ray film.

Adult↗