PubMed Health⌕ Search

Biomedical subjects

L Symon

Publications and source records attributed to L Symon.

At least 199 records · Page 11Linked to original sources
PubMed1979

Floating Myodil--a new sign of fat in the ventricles.

A case in which a remarkable series of CT studies demonstrated a dermoid cyst is reported. There was leakage of fat into the ventricular system which caused hydrocephalus due to adhesions partly obstructing the fourth ventricular outlets. The latter was confirmed by a ventriculogram using Myodil which dissolved in, or combined with, the fat produced by the tumour. This resulted in a high attenuation substance of lower specific gravity than CSF, which appeared to cause acute ventriculitis.

Adult↗
PubMed1979

Cerebral blood-flow and viscosity in relative polycythaemia.

Cerebral blood flow (CBF), red-cell mass, and plasma volume were measured in 39 patients with venous haematocrit values in the range 0.47--0.58. Patients with true polycythaemia were thus excluded. The 39 patients studied fell into two groups--those with a measured red-cell mass in the high-normal range and those with normal red-cell-mass values but reduced plasma-volume values (the relative-polycythaemia, low-plasma-volume group). The mean CBF was low in both the high-normal red-cell-mass (HNRCM) group (45.8 ml/100 g/min) and low-plasma-volume (LPV) group (48.8 ml/100 g/min). The haematocrit in the HNRCM group was 0.504 and in the LPV group 0.513. In a control group of subjects with a mean haematocrit of 0.421 CBF was 68.6 ml/100 g/min. Venesection was associated with a significant rise in CBF in both groups of patients--to 59.7 ml/100 g/min in the HNRCM group and 65.0 ml/100 g/min in the LPV group. Whole-blood viscosity fell significantly in both groups. Both groups demonstrated significant inverse relationships between CBF and haematocrit and between CBF and blood viscosity.

Adult↗
PubMed1979

Smoking and subarachnoid haemorrhage.

A retrospective study of 208 patients with ruptured cerebral aneurysms showed a highly significant excess of cigarette smokers among both men and women compared with the expected incidence. Results suggested that continued smoking increases the risk of suffering a subarachnoid haemorrhage (SAH) by a factor of 3.9 for men and 3.7 for women. Other factors besides smoking must affect the genesis of aneurysmal SAH since it is found in non-smokers, but continued cigarette smoking appears to increase substantially the risk of aneurysmal SAH occurring.

Adolescent↗
PubMed1979

An intravenous 133xenon clearance technique for measuring cerebral blood flow.

An intravenous 133Xe clearance technique for measuring cerebral blood flow (CBF) is described. Results obtained compared well with those using the intracarotid 133Xe technique. The reproducibility of the method was checked by repeating measurements within a few hours in 14 patients, when no significant overall change occurred, and after some days in 23 patients when a mean fall in flow of 8% was observed. CBF was measured in 52 control subjects. The mean fast component flow (Ff) was 68.6 ml/100 g/min (SD 11.3). No difference between the two hemispheres was found. Flow was confirmed to be higher anteriorly in the cerebral hemispheres. A significant inverse correlation was found between CBF and age.

Age Factors↗
PubMed1979

Central conduction time as an index of ischaemia in subarachnoid haemorrhage.

Central conduction time (CCT) has been measured in 12 healthy volunteers, and in 16 patients admitted to a neurosurgical unit following subarachnoid haemorrhage. Twelve of the patients were subsequently operated upon for the obliteration of an intracranial aneurysm. CCT has been found to have low standard deviation in control cases, and in the normal side following subarachnoid haemorrhage from aneurysms in the Circle of Willis, and to be prolonged during the development of ischaemic complications, either of the haemorrhage or following surgery. Evidence so far suggests that CCT may be useful as a monitor of developing ischaemia in association with surgery for subarachnoid haemorrhage.

Adult↗
PubMed1979

Surgical treatment of giant pituitary adenomas.

Multidirectional extension and invasive spread are important features of giant pituitary adenomas. Operability cannot be established merely by determining the size of the most prominent part of the tumour. Detailed radiological evaluation with plain films, computed tomography, angiography, and air studies all contribute to evaluation of the precise anatomy before surgery. In the final decision risks of surgical treatment must be balanced against the patient's age and prospects of long-term useful survival. Unfavourable cases for surgical treatment in our hands were those tumours embedded in the hypothalamus with thalamic and posterior extensions. Partial removal of such cases gave poor results. Where the mass proves soft, radical excision may be possible, but not otherwise. Limited biopsy for histological study, followed by a shunt procedure and x-ray therapy seems still the only recourse.

Adenoma↗
PubMed1979

Transcranial management of pituitary tumours with suprasellar extension.

A consecutive series of 101 pituitary tumours treated in the 10 year period 1968-78 has been examined, giant lesions being excluded. There were 48 female cases and 53 male, women predominating in the ratio of three to two in the age group 40-50 years and men showing a slight predominance in the age group 50-60 years. Most cases presented with visual deterioration which in 22 cases had been present for between one and two years, and in a further 22 for an even longer period, between two and 10 years. All patients underwent subfrontal craniotomy with mainly radical excision of the tumour followed by radiotherapy. The operative mortality was 0.99%. A system of grading of visual field defect has been described and used to compare preoperatively visual loss with postoperative visual recovery. Fifty-six per cent of cases returned to normal vision over the first two years, and a further 37% showed appreciable improvement in visual fields or acuity or both. Six per cent of cases showed no improvement in visual fields, and one patient died of postoperative deep vein thrombosis and pulmonary embolism. The degree of visual improvement has been correlated with the extent of visual defect, length of visual complaint, and size of the tumour. The importance of central and peripheral visual field analysis is emphasised yet again.

Adenoma, Acidophil↗
PubMed1979

Difficulties in diagnosis of supratentorial gliomas by CAT scan.

The false positive and false negative computed tomography diagnoses of glioma made using an EMI 1010 machine on a consecutive series of patients seen over a period of two years are recorded. About 1.5% of gliomas were not detected on initial CAT scan, 6.5% were misdiagnosed as benign lesions, and in 6.5% of the cases identified as glioma a non-malignant condition was subsequently diagnosed.

Brain↗
PubMed1979

Lyophilised dura mater: experimental implantation and extended clinical neurosurgical use.

The historical development of dural substitutes and the process of regeneration of dura mater are reviewed. Lyophilised human cadaver dura mater has been implanted intracranially in baboons and the graft shown to be incorporated with vascularisation but with ossification. In the human, lyophilised dura mater used as a dural substitute also becomes a viable tissue but without ossification. A retrospective study of its use in 100 neurosurgical patients showed a low complication rate and it is suggested that there are occasions when the ready availability of lyophilised dura mater, without the need for a further incision, makes it the dural substitute of choice.

Animals↗
PubMed1979

Intracranial rhabdomyosarcoma producing bulbar palsy.

Two cases of intracranial rhabdomyosarcoma invading the meninges at the base of the skull, causing progressive bulbar palsy and rapid demise, are presented. Discussed are the clinical aspects of this uncommon tumour of interest to the neurosurgeon.

Adolescent↗
PubMed1979

[Effects of nicergoline on cerebral blood flow (author's transl)].

Cerebral blood flow (CBF) was measured before and after i.v. injection of the cerebral vasodilator 10-methoxy-1,6-dimethyl-ergoline-8 beta-methanol-(5-bromonicotinate) (nicergoline, Sermion) in 13 patients with cerebrovascular disease. CBF increased in seven. The possibility is discussed that the effect of the drug in the other patients may have been masked by a fall of CBF which occurs during sequential measurement of patients at rest. Nicergoline is an alpha-adrenergic receptor blocking agent which affects cerebral blood flow by reducing cerebrovascular resistance. The present study was undertaken to assess the acute effect of the drug on cerebral blood flow and blood pressure in patients with cerebrovascular diseases.

Cerebrovascular Circulation↗
PubMed1978

Extradural haemangiolipoma in the spinal canal. Two cases presenting during pregnancy.

Extradural spinal haemangiolipomas are very rare but they account for forty per cent of all lipomas in this position. The two cases described here were middleaged women who both had a paraparesis during their pregnancy which remitted after parturition. Both tumours were in the thoracic region on the posterior surface of the dura. The histological appearances were those of a lipoma with a definite capillary component. The pathogenesis of the relapsing and remitting paraplegia and its relationship with pregnancy is probably multi-factorial. It is proposed that both blood volume and extra-cellular fluid volume changes occurring during pregnancy may be responsible for the fluctuating cord compression. Similarly the hypothesis is put forward that due to the vascularity of the tumour it exerts a "steal" phenomenon over the blood supply to the adjacent cord. Also, because of its vascularity, the tumour could have a pulsatile compressive effect on the cord.

Female↗
PubMed1978

Disordered cerebro-vascular physiology in aneurysmal subarachnoid haemorrhage.

The technical problems of surgery for anterior circle aneurysm have in large measure been solved. The problem of reduced perfusion to the brain which characterises the patient with aneurysmal subarachnoid haemorrhage in a poor clinical condition demands more subtle physiological handling. It appears likely that maintenance of an intact cell membrane and blood brain barrier may be aided by the exhibition of pre and post-operative steriods, and that concentration on regional perfusion should be the main aim in post-operative management of such cases. This demands maintenance of adequate blood volume, avoidance of platelet stickiness, and utilisation of the pathological paralysis of autoregulation to improve flow to ischaemic zones by hypertensive agents if necessary. The possibility that early operation with evacuation of blood from the basal cisterns may in the end prevent the vascular damage and disordered vaso-reactivity which encourages the development of transient ischaemic deficits, is a concept which has to be actively pursued. The problem is a continuing one which has bedevilled aneurysm surgery for 25 years, but the omens suggest that a solution is appreciably nearer at hand.

Blood-Brain Barrier↗