Amino acids in retinitis pigmentosa.

A survey of fasting whole blood amino acids in 65 patients with various subtypes of retinitis pigmentosa performed. Eight X-linked recessive patients showed decreased taurine and aspartate. Nineteen autosomal recessive patients, and to lesser extent 10 autosomal dominant patients, showed reduced levels of whole blood threonine and histidine.

Substance P: immunohistochemical localization and effect upon cat pial arteries in vitro and in situ.

1. Nerve fibres containing substance P immunoreactivity were present in the adventitia and the adventitia-media border of all cat cerebral arteries which were examined. Substance P immunoreactivity was most abundant in cerebral arteries from the rostral portion of the circle of Willis.

The effects of chloral hydrate anesthesia on the metabolic response in the substantia nigra to apomorphine.

The effects of apomorphine (1 mg/kg) upon glucose utilization in the substantia nigra (pars compacta) have been examined with 2-deoxyglucose autoradiography in conscious rats and rats anesthetized with chloral hydrate. In conscious rats, apomorphine increased glucose use by 23%, whereas in the anesthetized rats, apomorphine decreased glucose use by 24%. These divergent responses to apomorphine highlight the difficulties associated with the use of chloral hydrate anesthesia in the study of nigro-striatal systems.

Chemonucleolysis for relief of sciatica due to a herniated intervertebral disc.

Chemonucleolysis is the nonoperative chemical removal of displaced lumbar disc material. The enzyme chymopapain, which has a wide margin of safety between its effective therapeutic and toxic doses, is effective in the management of sciatica due to a herniated intervertebral disc. The patient will have leg pain as the dominant symptom and a 50% reduction in straight-leg raising with or without bowstring discomfort and crossover pain.

Heterogeneous depression of glucose utilization in the caudate nucleus by GABA agonists.

Local cerebral glucose utilization in the rat caudate nucleus has been examined following the intravenous administration of the GABA agonists muscimol and THIP. Although glucose utilization was reduced throughout the striatum following GABA agonists, the magnitude of the reductions in the lateral portion of the nucleus were markedly greater than in other portions of the caudate nucleus. This medial--lateral heterogeneity in response to GABA agonists contrasts with the known rostral--caudal heterogeneity in the distribution of biochemical markers for GABA.

Hyperornithinaemia and gyrate atrophy of the retina: improvement of vision during treatment with a low-arginine diet.

A 15-year-old patient with hyperornithinaemia (0.6--1.2 mmol/l) and gyrate atrophy of the retina was given a low-arginine diet to reduce plasma ornithine to a concentration (0.

Focal cerebral ischaemia in the rat: 2. Regional cerebral blood flow determined by [14C]iodoantipyrine autoradiography following middle cerebral artery occlusion.

Local cerebral blood flow has been measured by quantitative autoradiography, employing [14C]iodoantipyrine as tracer, in rats killed half an hour after occlusion of the middle cerebral artery. The results were compared with pattern of local cerebral blood flow (CBF) in sham-operated rats and with neuropathological findings. In every animal there was a profound reduction (to 13% of control levels)in blood flow in the neocortex previously by the occluded artery.

Focal cerebral ischaemia in the rat: 1. Description of technique and early neuropathological consequences following middle cerebral artery occlusion.

A procedure for occluding the stem of the proximal middle cerebral artery of the rat is described. The operation is performed under anaesthesia through a small subtemporal craniectomy. After occlusion, 3 animals were perfused with carbon block and 8 with a FAM fixative (40% formaldehyde, glacial acetic acid, and methanol).

Alterations in local cerebral glucose utilisation in specific thalamic nuclei following apomorphine.

The alterations in local cerebral glucose utilisation in eight discrete nuclei in the thalamus following the administration of apomorphine (0.5 mg kg-1) have been investigated with the autoradiographic 2-deoxyglucose technique in 11 conscious rats. In two thalamic nuclei (parafascicular and ventrolateral nuclei), glucose utilisation was significantly elevated following apomorphine; in two thalamic nuclei (the anterior medial and anterior ventral nuclei), glucose utilisation was significantly reduced following apomorphine; and in four nuclei (lateral geniculate, medial geniculate, mediodorsal, and lateral thalamic nuclei), glucose use was unchanged.

Effects of pentobarbital on contractile responses of feline cerebral arteries.

The effects of pentobarbital on the contractile responses of isolated feline middle cerebral arteries have been examined. In the presence of pentobarbital (3 x 10(-4)M), the maximum contractions effected by potassium, noradrenaline, and prostaglandin F2 alpha were reduced by 37 +/- 3, 69 +/- 3, and 10 +/- 6%, respectively. The results caution against the use of pentobarbital as an anaesthetic agent in investigations of cerebrovascular reactivity.

Variation of the lumbosacral myotomes with bony segmental anomalies.

Clinical localisation of a disc prolapse required dependable knowledge of the muscles supplied by the lumbosacral nerve roots. Localisation is most difficult in the 10 per cent of patients who have lumbosacral bony segmental anomalies. The lumbosacral plexus has been dissected in 11 cadavers with such anomalies and electrical stimulation studies carried out in 15 patients similarly afflicted.

Cerebral circulatory and metabolic effects of piribedil.

Two aspects of the cerebrovascular action of the putative dopaminergic agonist, piribedil, have been examined. The vasomotor responses of isolated feline middle cerebral artery to piribedil and its metabolite, S584, were first examined and the effects of piribedil upon cerebral blood flow, cerebral oxygen consumption and the electroencephalogram (EEG) were then investigated in anaesthetised baboons. Neither piribedil nor S584 displayed any marked vasomotor efficacy in vitro, with small changes in tension being observed only with large concentrations (greater than 10(-4) M).

Influence of dopaminergic systems on the lateral habenular nucleus of the rat.

The alterations in glucose utilization in the lateral habenular nucleus following the systemic administration of a putative dopaminergic agonist and antagonist have been examined in 48 rats by means of the autoradiographic 2-deoxyglucose technique. The administration of apomorphine (0.15--5 mg/kg) resulted in significant dose-dependent reductions (by 25 +/- 5% following 0.

Pathological findings from two cases of choroideremia.

Light and electron microscopic study of material from two cases of old, quiescent choroideremia led to three conclusions: there was nearly total loss of the outer segments of the visual receptors, there was reduplication of the basement membrane of the pigment epithelium and thickening of Bruch's membrane, and there was gliosis of the inner part of the retina and a preretinal membrane.

Cerebral circulatory and metabolic effects of vasoactive intestinal polypeptide.

Two aspects of the action of vasoactive intestinal polypeptide (VIP) within the cerebral vascular bed have been examined. First, in anesthetized rats, the vasomotor responses of individual pial arterioles on the convexity of cerebral cortex to the perivascular microinjection of vasoactive intestinal polypeptide were examined and, second, in anesthetized baboons, the effects of VIP on cerebral blood flow, cerebral oxygen consumption, and the electroencephalogram (EEG) were investigated both prior to and following the osmotic opening of the blood-brain barrier. The perivascular microinjection of VIP resulted in statistically significant increase in arteriolar caliber in the concentration range 10(-9) to 10(-6) M.

Nonorganic physical signs in low-back pain.

Nonorganic physical signs in low-back pain are described and standardized in 350 North American and British patients. These nonorganic signs are distinguishable from the standard clinical signs of physical pathology and correlate with other psychological data. By helping to separate the physical from the nonorganic they clarify the assessment of purely physical pathologic conditions.

Retina-dependent activation by apomorphine of metabolic activity in the superficial layer of the superior colliculus.

Studies of the effect of the dopamine agonist apomorphine on local cerebral glucose utilization by means of the carbon-14-labeled deoxyglucose method demonstrate a dose-dependent metabolic activation in the superficial layer of the superior colliculus in the rat. Apomorphine stimulated glucose utilization in a number of other cerebral structures, but only the effect in the superficial layer of the superior colliculus depended on an intact retinal input. This effect was present with the animal in the light or in the dark, but was abolished by enucleation, which left the effects in other cerebral structures unimpaired.