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Biomedical subjects

J Marshall

Publications and source records attributed to J Marshall.

At least 559 records · Page 31Linked to original sources
PubMed1977

The role of axoplasmic transport in the pathogenesis of retinal cotton-wool spots.

Small retinal arterioles in the pig retina were occluded by argon laser photocoagulation and the morphology and topography of the resulting lesions studied by ophthalmoscopy, histology, and electron microscopy. Two days after laser coagulation ischaemic necrosis of the inner retina was observed in the territory of occluded arterioles, and swollen axon terminals packed with cytoplasmic organelles were found in the retinal nerve-fibre layer on the peripheral border of the infarcts and their border nearest to the disc. These swellings gave rise to localised zones of opacification (cotton-wool spots) at the borders of the retinal infarcts, and similar zones developed in relation to the laser burns. Amino-acid uptake and transport in retinal ganglion cells was studied in these animals by autoradiography following an intravitreal injection of tritiated leucine. When 3H-leucine was injected at the same time as laser coagulation and arteriolar occlusion, label became concentrated in the swollen axon-terminals on the peripheral aspect of 2-day-old infarcts but was absent from the terminals on the disc side of infarcts. The accumulation of 3H-leucine and organelles was attributed to interruption of orthograde axoplasmic transport. When 3H-leucine was injected into the vitreous 2 days prior to laser occlusion, label became distributed throughout the axoplasm and then accumulated in swollen axon terminals on both sides of infarcts after a further 2 days. An obstruction to both orthograde and retrograde axoplasmic flow was thus demonstrated. We concluded that cotton-wood spots should be redefined as accumulations of cytoplasmic debris in the retinal nerve-fibre layer caused by obstruction of orthograde or retrograde axoplasmic transport in ganglion cell axons.

Animals↗
PubMed1977

Cerebrovascular incidents after myocardial infarction.

Pathological studies show a high correlation between the degree of atheroma in coronary, cerebral, and carotid arteries. Necropsy evidence of myocardial infarction also shows a high prevalence of severe atheroma in the carotid arteries. A further pathological finding is that obstruction in cerebral and carotid circulations is commonly due to embolism from the heart. In contrast, long-term follow-up of survivors of myocardial infarction indicates a low prevalence of cerebrovascular disease. To test if this low prevalence is due to lack of clinical ascertainment, a study was made of 260 survivors of myocardial infarction followed for five years. Specific attention was given to eliciting any clinical manifestations of cerebrovascular disease. In this study it was confirmed that in survivors of myocardial infarction the prevalence of cerebrovascular disease is surprisingly low: completed strokes 4%, transient cerebral ischaemic attacks 2%. A possible explanation of the low prevalence is that after the acute episode of myocardial infarction attacks of cardiac dysrhythmia predisposing to systemic embolism become infrequent.

Adult↗
PubMed1977

Evidence of silent cerebral embolism in patients with amaurosis fugax.

In 34 patients who presented with attacks of amaurosis fugax with no evidence of cerebral involvement, EEG, angiographic, and regional cerebral blood flow studies were carried out. Six of 23 EEGs, one of 21 angiograms, and five of six regional blood flow studies were thought to provide evidence of silent cerebral embolism. The implications for the management of patients who present with isolated amaurosis fugax are discussed.

Adult↗
PubMed1977

Effect of nicergoline on cerebral blood flow.

Cerebral blood flow (CBF) was measured before and after intravenous injection of the cerebral vasodilator nicergoline in 13 patients with cerebrovascular disease. CBF increased in seven. The possibility that the effect of the drug in the remainder may have been masked by a fall of CBF which occurs during sequential measurement of patients at rest is discussed.

Cerebrovascular Circulation↗
PubMed1977

Spinal injury at the level of the third and fourth cervical vertebrae from football.

Acute traumatic lesions of the spine at the third and fourth cervical levels without associated fracture are not common. The eight lesions in this report occurred as a result of injuries sustained during tackle football. They included acute intervertebral disc herniation, anterior subluxation of the third cervical vertebra on the fourth, unilateral dislocation of the joint between the articular processes, and bilateral dislocation of the joints between the articular processes. The mechanism of injury was the use of the top or crown of the helmet as the primary point of contact in a high-impact collision when blocking, tackling, or head-butting. To avoid a seemingly inevitable increase in the incidence of these lesions occurring from tackle football, coaches and officials will have to modify the current techniques of blocking tackling, and head-butting.

Adolescent↗
PubMed1976

Angiographic appearance of carotid bifurcation in pateints with completed stroke, transient ischaemic attacks, and cerebral tumour.

The angiographic appearance of the carotid bifurcation was compared in groups of patients aged 50-59 suffering from transient ischaemic attacks (40 cases), cerebral infarction with completed stroke (44 cases), and cerebral hemisphere tumour (66 cases). Carotid occlusion was found in 14% of those with infarcts and 5% of those with transient ischaemic attacks. Carotid stenosis was found in 40% of those with ischaemic attacks and 14% of those with infarcts. Minor irregularity of the carotid arterial wall was equally common in all three groups.

Angiography↗
PubMed1976

Evaluation of the McCarey-Kaufman technique of corneal storage.

We present our evaluation of the McCarey-Kaufman (M-K) method of corneal storage. Sixty-six rabbit corneas were stored in the M-K medium at 4 C for periods of four, eight, and 12 days. Endothelial viability was assessed, using the specular microscope, the phenomenon of temperature reversal, and known inhibitors of endothelial cell function. Our results support those of McCarey and Kaufman, who showed that rabbit corneas will remain viable when stored by this technique. We were unable to support the contention that M-K medium-stored corneas are functionally superior to those corneas stored in moist chambers in the conventional manner. An unsuccessful attempt was made to correlate the function of the endothelium with either its morphological appearance as seen through the specular microscope or changes in ultrastructure as shown by transmission electron microscopy.

Animals↗