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Biomedical subjects

B K Weir

Publications and source records attributed to B K Weir.

At least 91 records · Page 5Linked to original sources

Clinical - radiological correlates in intracerebral hematomas due to aneurysmal rupture.

In this series of intracerebral hematomas from aneurysmal rupture, gathered from several neurosurgical services, certain morphological features were studied in detail. Patients with very large hematomas tended to have poor neurological grades on admission to hospital and their immediate discharge outlook was correspondingly poor. Ruptured middle cerebral and pericallosal artery aneurysms were relatively common causes of intracerebral hematomas. Patients with temporal lobe hematoma did relatively well; those with parietal hematoma did poorly. The larger the hematoma the less chance there was of developing cerebral vasospasm but the more likely was pre-operative brain herniation. The survival was more closely linked to size and location of the hematoma than to the location of aneurysm or the degree of midline shift.

Cerebral Hemorrhage↗

Meningitis complicating transsphenoidal hypophysectomy.

The case records of 98 patients who underwent a transsphenoidal hypophysectomy between 1969 and 1979 were examined to establish the frequency of postoperative cerebrospinal rhinorrhea and meningitis. There were seven cases of rhinorrhea and six of meningitis following the procedure. Five of the six patients with meningitis had diabetes mellitus and three of the seven with rhinorrhea had meningitis; thus, both diabetes and rhinorrhea were established as significant risk factors (P less than 0.001) in the development of meningitis after this operation. There were two proven cases of meningitis due to anaerobic organisms and a further two suspected cases. The prophylactic use of antibiotics did not prevent the development of meningitis in this series of patients.

Adult↗

Effects of various intracranial fluids on smooth muscle.

Samples of cerebrospinal fluid (CSF) drawn from patients with subarachnoid hemorrhage, subdural hemorrhage, or brain tumor, as well as control samples from patients without a known cerebral pathological condition, were tested for their ability to contract smooth muscle. Canine middle cerebral artery, canine basilar artery, and rat stomach fundus were used, and contractions were expressed as the percentage of the contraction elicited by a standard dose of 5-hydroxytryptamine. All samples that contained blood produced contractions of the smooth muscle preparations, and despite a large sample no significant differences were observed in the magnitude of the contractions either between preparations or between samples from different groups of patients. Control samples were generally without significant effect. Neither methysergide, a 5-hydroxytryptamine antagonist, nor indomethacin, an inhibitor of prostaglandin synthesis, significantly diminished the contractions induced by bloody CSF, although the calcium antagonist D600 successfully antagonized the response in all groups. D600 was a better antagonist of the action of blood-containing CSF on cerebral artery than on stomach fundus. Samples obtained from patients with angiographic evidence of vasospasm were significantly more active than those obtained from patients without vasospasm, but the latter retained considerable activity.

Animals↗

Characterization of a pituitary stone.

Calcification of the pituitary is unusual and functional studies of such cases have not been previously reported. We have been able to document persistent prolactin secretion both in vivo and in vitro in a patient with a severely calcified pituitary adenoma ("pituitary stone"), and have also documented prolactin granules within the calcified tissue mass. Normal menstrual function was restored after surgical removal of the "stone," and galactorrhea subsided although the prolactin response to thyrotropin-releasing hormone (TRH) remained abnormal. Two years after surgery the menstrual cycle has remained regular, but galactorrhea has recurred, emphasizing the need for prolonged follow-up in patients with prolactin-producing adenomas, despite apparent surgical cure. The in vitro studies showed that human pituitary tissue is secretory in culture and thus may serve as a useful tool for physiologic studies of the pituitary cell.

Adenoma↗

Prospective study of 100 lumbosacral discectomies.

A prospective study of 100 patients undergoing discectomy was carried out. The neurological findings were documented preoperatively and at 1 month and 1 year postoperatively. The clinical and radiological data were analyzed with respect to significant associations. There were no complications. At a minimum of 1 year postoperatively, 63% of patients had complete relief of back pain and 73% had complete relief of leg pain. A discriminant analysis equation was derived which assessed the relative significance of factors as determinants of outcome. A method is given for estimating whether a patient will have a good or a poor outcome following the discectomy. Factors shown to be of significance should be recorded in prospective series to allow for comparison as to the efficacy of different methods of treatment. The results are better than those described for chemonucleolysis.

Adult↗

Cerebrovascular responses to subarachnoid blood and serotonin in the monkey.

Preliminary in vitro experiments were performed to determine the serum concentration of serotonin in the monkey, and the ability of cyproheptadine to block serotonin and serum-induced contractions in monkey cerebral arteries. Thirty-four cynomolgus monkeys were subsequently used to study changes in regional cerebral blood flow (CBF) obtained by the intracartoid 133Xe technique, and in the angiographic cerebral arterial caliber resulting from subarachnoid injection of artificial cerebrospinal fluid (CSF), blood, and serotonin. Five animals in each injection group were given 1.0 mg/kg intravenous cyproheptadine (a serotonin-blocking agent) during the post-injection period. Subarachnoid injection of artificial CSF produced no change in CBF or arterial caliber. Post-injection administration of cyproheptadine also had no effect on these parameters. A subarachnoid injection of fresh autogenous blood produced a significant but transient (less than 1 hour) decrease in CBF and moderate vasospasm, which lasted at least 3 hours. This vasospasm was essentially unaffected by intravenous cyproheptadine. The CBF and arterial caliber were unchanged following a subarachnoid injection of serotonin at concentrations (5 x 10(-6)M) present in normal monkey serum. In contrast, 5 x 10(-6) M serotonin invariably produced near maximal contractions in the in vitro cerebral artery preparations. Higher (x10) serotonin concentrations caused a transient CBF response similar to that obtained with blood. However, the cerebral vasospasm induced was of shorter duration than that obtained with blood. These results do not support a major role for serotonin in the production of post-subarachnoid hemorrhage vasospasm. Moreover, our data indicate that in vitro experiments do not reflect the ability of serotonin to constrict cerebral arteries in the intact animal.

Animals↗

Pulmonary edema following fatal aneurysm rupture.

A retrospective clinico-pathological analysis of 78 cases of fatal subarachnoid hemorrhage (SAH) was carried out: 71% had a pathological diagnosis of pulmonary edema (PE), and of these 31% had a clinical diagnosis of PE. Patients with pathological PE were younger and died sooner after their SAH than those without. The incidence of PE fell with the passage of time following SAH, while the occurrence of pneumonia and embolism increased. There were hypoxemia and hypocapnia in both groups, more severe in the group that had pathological PE. The pathophysiology of neurogenic PE is discussed and possible therapeutic approaches indicated.

Adult↗