Effects of radiation on cerebral vasculature: a review.
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Blood Vessels↗
Biomedical subjects
O Major
Publications and source records attributed to O Major.
In vitro contractility studies of the rat middle cerebral artery after stereotactic Gamma Knife radiosurgery.
The middle cerebral artery (MCA) was irradiated in 94 rats using the Gamma Knife. The vessels receiving 20, 50, 80 and 200 Gy were removed 24 h later and mounted on a myograph. Contractility responses to potassium and prostaglandin (PG) F2 alpha were tested. After precontraction with PGF2 alpha, the relaxant effects of histamine, papaverine, L-arginine and sodium nitroprusside were examined. Other vessels were preincubated with ouabain or N omega-nitro-L-arginine methyl ester before testing with the relaxant agents. After irradiation, the contractile response to maximal potassium and PGF concentrations was diminished, suggesting dose-dependent radiation damage to the contractile mechanism. The normal MCA shows an initial relaxation in the presence of a low K+ concentration, which is Na+, K(+)-ATPase dependent. According to this study, the endothelium-derived relaxation function was suppressed by radiation, suggesting that there is an early change in irradiated vessels, demonstrable by functional studies, which affects both the smooth muscle and endothelial layers.
Animals↗
Slit-ventricle syndrome in shunt operated children.
Chronic intracranial hypotension is considered as a frequent complication in shunted hydrocephalus, besides obstruction and shunt-infections. In the last twenty years 32 cases of slit-ventricle were diagnosed among the more than one thousand operations on hydrocephalic children at the Paediatric Department of the National Institute of Neurosurgery, Budapest, Hungary. Most of them have been operated on in infancy. Time from the first operation to the development of slit-ventricle ranged from one to twelve years, the mean was 6.5 years. Seven patients were symptomless (22%), while 25 patients (78%) had more or less severe slit-ventricle syndrome with headache (25 cases), nausea/vomiting (23 cases), altered consciousness (21 cases), brainstem signs (12 cases), and epileptic fits (2 cases). Ten patients with moderate clinical signs improved under conservative treatment. In 15 cases an anti-siphon device (ASD) was implanted. In five of them the clinical result was good, but in the remaining 10 cases typical hypertensive signs were seen. In these cases low flow rate valves were implanted instead of the middle flow rate valve and ASD. In one case the intracranial hypertension persisted, so a middle flow rate shunt system was "reimplanted" and finally the patient improved. In this study the experiences with these 32 cases will be analysed and discussed. The authors stress the primary use of combined valves to avoid the slit-ventricle syndrome.
Cerebrospinal Fluid Shunts↗
Pathological characteristics of surgically removed craniopharyngiomas: analysis of 131 cases.
Pathological specimens of 131 surgically removed craniopharyngiomas were obtained from the registry of the National Institute of Neurosurgery, Budapest between 1977 and 1991. The cases were reviewed statistically with reference to their gross and microscopic features and clinical characteristics. Macroscopically, 34% of the tumours were cystic, 23% solid and 43% mixed. Histologically, 38% of the cases belonged to the adamantinous group, 26% were squamous epithelial type, 15% were combined, that is expressing the characteristics of both. In 21% of the cases the surgically removed samples did not contain enough material for correct histopathologic classification. There was no recurrence in the group with the squamous epithelial type tumours, while 59% of the adamantinous, and 36% of the combined craniopharyngiomas recurred. The 5-year survival proportion was 73% at the squamous epithelial, 60% in the adamantinous, and 55% at the combined histological types.
Adolescent↗
Chronic extradural haematoma--report of 33 cases.
During 35 years (1955-1989) 236 extradural haematomas were operated on in the National Institute of Neurosurgery, Budapest. 33 of them were operated on after the 4th day following trauma. These cases were termed as chronic ones. There was no mortality and only two patients had permanent neurological signs. The much more favourable outcome of the chronic extradural haematoma could be explained with the slow development of the haematoma. It is remarkable that the trauma itself was not recognised in several cases.
Adolescent↗
Spontaneous spinal epidural haematomas.
The spontaneous spinal epidural haematoma (SSEH) is a rarity, but the severe and permanent motor disability underlines its importance. From 1957 seven cases of SSEH have been diagnosed and operated on in the National Institute of Neurosurgery, Budapest. These cases are analysed and discussed. The clinical picture began with local pain of the spine and radicular signs but some hours or days later paraparesis or paraplegia and incontinence developed. In the discussed cases the neurological deficit progressed to complete para- or tetraplegia in 5 cases. Only 2 patients had partial spinal transverse lesions on admission. All patients underwent myelography to detect the spinal space occupying lesion and were operated on soon. Three patients recovered completely, 2 remained partly and 2 totally paralysed. The outcome depended mainly on the timing of neurological deficiency. If the neurological signs existed less than 8 hours the patients recovered completely or fairly well while the prognosis was poor if the transverse lesion persisted longer than 24 hours. The authors stress the importance of correct and fast decisions at the first medical examination for the outcome of this disease, because only immediate transfer to a neurosurgical department gives a chance of good recovery.
Adolescent↗
Continuous monitoring of blood-brain barrier opening to Cr51-EDTA by microdialysis following probe injury.
Continuous detection of the permeability changes of the blood-brain (BB) interface became feasible with the recent development of the cerebral microdialysis technique. Vasogenic brain oedema was induced by the insertion of the dialysis capillary into the cerebral cortex of rats, and blood-brain transfer was measured with Cr51-EDTA as a blood-born tracer. The dialysis capillaries had an upper limit of 500 daltons (MW). Ringer solution was perfused through the dialysis tube. Samples were collected continuously. The permeability coefficient has been calculated from the radioactivity of the serum and of the washing fluid.
Animals↗