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Biomedical subjects

G du Boulay

Publications and source records attributed to G du Boulay.

At least 19 recordsLinked to original sources
PubMed1992

Psychotic illness in multiple sclerosis. A clinical and magnetic resonance imaging study.

Ten patients with multiple sclerosis (MS) and psychosis were assessed using the Present State Examination, and matched retrospectively with respect to age, disability, duration of symptoms, and disease type with 10 MS patients without psychosis. Both groups underwent MRI of the brain. There was a trend for the psychotic group to have a higher total lesion score, particularly around the periventricular areas. This reached statistical significance in the areas around the temporal horn. In all cases, neurological symptoms preceded the onset of psychosis. The psychotic group also had a later age of onset of psychosis than psychotic patients without brain disease. These results point to an aetiological association between the pathological process of MS and psychosis.

Adult↗
PubMed1983

The role of hemoglobin in the etiology of cerebral vasospasm. An in vivo study of baboons.

Oxyhemoglobin was injected intracisternally into three baboons, and methemoglobin into one baboon, in an attempt to mimic the prolonged cerebral arterial spasm sometimes seen after subarachnoid hemorrhage due to aneurysm rupture. Cerebral angiography was performed for up to 7 days after injection of hemoglobin, and the degree of vasospasm was estimated from the angiograms. Oxyhemoglobin caused slight arterial narrowing, which lasted for 3 days. Methemoglobin had no significant effects. Motor neurological deficits and histopathological signs, characteristic of prolonged cerebral vasospasm, were not observed. It was concluded that hemoglobin alone is not capable of causing the cerebral vasospasm syndrome in these experimental animals.

Animals↗
PubMed1980

The distribution of 125I-metrizamide and 125I-diatrizoate between blood, brain and cerebrospinal fluid in the rabbit.

The entry of 125I-metrizamide and of 125I-diatrizoate from blood into brain has been studied in rabbits. The blood-brain barrier is very tight to both molecules, all cerebral regions having spaces between 0.5 and 2% after maintenance of constant blood levels for 4 h. In extraneural tissues both compounds appear to distribute in extracellular fluid except for accumulation of metrizamide by the liver and perhaps the small intestine. Profiles of radioactivity through cerebral gray matter have been obtained following ventriculocisternal perfusion of artificial cerebrospinal fluid containing 125I-metrizamide. The nature of these profiles and their behavior with time suggest that metrizamide passes through gray matter by simple diffusion, that it is largely distributed in the extracellular fluid and that bake movement across the blood-brain barrier is small.

Animals↗
PubMed1976

A comparison of computer asisted tomography (EMI scanner) with conventional neuroradiologic methods in the investigation of patients clinically suspected of intracranial tumor.

Computerized tomography has been used as the initial radiologic investigation among 212 intracranial tumor suspects. Ninety-five of these patients were ultimately shown to have tumors as a result of all their investigations. Eighty tumors were clearly defined by EMI scanning, four further scans were suspicious but not unequivocally abnormal and six scans showed complications of the tumor rather than the lesion itself. Thus, only five scans were falsely negative in the presence of a tumor. The false positive and false negative rates for EMI scanning have been compared with conventional techniques and computerized tomography shown to compare favourably with angiography or encephalography.

Brain Neoplasms↗
PubMed1975

The autoregulatory capability of Galen's rete cerebri and its connections.

The rete, a vascular system between the extra- and intracerebral arteries of certain animals, may have a variety of functions in different species. The calibres of the vessels of the rete and its arteries of supply have been measured under different conditions of blood pressure and PaCO2. It has been shown that the rete and its afferent arteries behave in an autoregulatory fashion down to a blood pressure of 60 mmHg. They also dilate with a rise in PaCO2. It has also been found that some parts of the system dilate even when the blood pressure drops lower than 60 mmHg. It is suggested that this autoregulatory capacity of extradural vessels limits the requirement for CSF spaces to change with blood pressure changes. A general rule has been sought which would link the known facts about cerebral autoregulation and the possession of extra- to intracranial anastomoses with the bodily shape and posture of the particular animal.

Animals↗
PubMed1975

Autoregulation in external carotid artery branches in the baboon.

The effects of changes in systemic blood pressure upon external carotid branches of the baboon have been measured by cerebral angiography. They have been shown to have an autoregulatory type of response down to a blood pressure of about 60 mmHg, below which they constrict.

Animals↗
PubMed1975

The vasodilator action of angiography with Urografin 60% on the basal vessels of the brain of the baboon.

Angiography under experimental conditions shows that Urografin has a vasodilator action of the order of 8% upon the basal cerebral arteries of the baboon. This action is not seen within the first 4 sec of the angiogram and the dilator effect of a single injection has passed off completely 15 min later. Three successive injections within 7 min show little evidence of cumulative vasodilatation. The vasodilator action of three successive angiograms has disappeared 22 to 29 min later. Because of wide variations in the degree of vasodilatation shown by individual baboons it may be necessary to use each baboon as its own control in subsequent work.

Angiography↗
PubMed1975

Normal measurements in angiography of the posterior fossa.

A quantitative study of the normal position of the vessels of the posterior fossa was made. The centroid proved to be the most accurate reference point for vessels near the midline. The presence or absence of antomical constraints is important in evaluation in significance of an unusual measurement. A combination of unusual measurements which are not intercorrelated and which make sense anatomically suggests that a mass is present.

Angiography↗
PubMed1973

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Angiography↗