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Biomedical subjects

F Gentili

Publications and source records attributed to F Gentili.

At least 37 records · Page 2Linked to original sources

Ventriculoperitoneal shunt malfunction during pregnancy.

Many women with cerebrospinal fluid shunts are now reaching reproductive age. Shunt malfunction may occur during pregnancy, and management requires a well-planned, combined neurosurgical and obstetrical approach. We present a case of ventriculoperitoneal shunt obstruction manifesting during the third trimester managed successfully in a conservative fashion. The literature on ventriculoperitoneal shunt malfunction during pregnancy is reviewed.

Adult↗

Gauze-induced granuloma ("gauzoma"): an uncommon complication of gauze reinforcement of berry aneurysms.

Incompletely and even adequately clipped berry aneurysms are often reinforced with finely shredded gauze. In seven female patients this practice led to a series of events including headache, pyrexia, seizures, cranial nerve deficits, endocrinopathy, cerebrospinal fluid pleocytosis, and an enhancing mass demonstrated by computerized tomography at the aneurysm site. One patient with blindness, hydrocephalus, and panhypopituitarism died and was examined at autopsy. Three additional female patients have been identified in the literature with similar case histories. It is suggested that in these patients the gauze induced a foreign-body granuloma, accompanied by progressive occlusion of neighboring small arteries. It would seem prudent to reserve gauze reinforcement for aneurysms that cannot be securely obliterated surgically.

Adult↗

Nimodipine treatment in poor-grade aneurysm patients. Results of a multicenter double-blind placebo-controlled trial.

A multicenter, randomized placebo-controlled double-blind trial of nimodipine in poor-grade aneurysm patients was carried out in 17 Canadian hospitals. Of 188 patients enrolled in the trial, 32 were excluded for protocol violations and two were excluded due to statistical considerations, leaving 154 patients for valid outcome analysis. Nimodipine treatment was associated with a significantly better outcome (p less than 0.001): 21 (29.2%) of 72 nimodipine-treated patients had a good outcome at 3 months after subarachnoid hemorrhage (SAH) compared to eight (9.8%) of 82 placebo-treated patients. Delayed ischemic deficits from vasospasm alone were significantly less frequent in the nimodipine group (p less than 0.05) with permanent deficits occurring in five nimodipine-treated patients (6.9%) and in 22 placebo-treated patients (26.8%). Improvement in the good outcome rate and reduction in delayed ischemic deficits from vasospasm alone occurred in both Grade 3 and 4 patients, with no difference between nimodipine- and placebo-treated patients being found in Grade 5 patients. Repeat angiography after Day 4 was carried out in 124 patients. There was no significant difference in the incidence of moderate or severe diffuse spasm, which was seen in 64.3% of nimodipine-treated patients and 66.2% of placebo-treated patients. The authors conclude that nimodipine treatment in poor-grade patients with SAH results in an increase in the number of good outcomes and a reduction in the incidence of delayed neurological deterioration due to vasospasm. This effect occurs by a mechanism other than prevention of large-vessel spasm as visualized on angiography.

Adolescent↗

A technique for rapid non-suture vascular anastomosis.

In an attempt to overcome some of the difficulties inherent in vascular anastomosis using standard suture methods, we have developed a technique that allows for rapid non-suture anastomosis of blood vessels. The technique has been used in over 400 anastomoses, including interposition vein grafts in rat, rabbit and dog vessels ranging in size from 0.7 mm to 3 mm in diameter. Animals have been followed for over 1 year postoperatively with serial angiography and histological evaluation including scanning electron microscopy. Stress studies have compared the biomechanical properties of both non-suture and suture anastomosis. The overall patency rate in non-suture end-to-end anastomoses using an interposition vein graft was 85% at 1 year follow up. Histological evaluation revealed a healing pattern that was temporally similar to that of the suture technique. Stress tests revealed no significant difference between suture and non-suture technique. These studies reveal that the non-suture technique compares favourably with the suture technique, and demonstrate the feasibility of applying this technique to man.

Animals↗

Monitoring of sensory evoked potentials during surgery of skull base tumours.

Despite advances in instrumentation and the use of microsurgical techniques, neurosurgical procedures involving extensive areas of skull base or other critical areas of brain still carry significant risk for neurological injury. The use of intraoperative recording of sensory evoked potentials (SEP) has been advocated to monitor neurologic function during these major neurosurgical procedures to reduce the risk of injury to neural structures. This report summarizes our experience with intraoperative monitoring of SEP in over 200 patients, and details our findings in a group of 12 patients with skull base and posterior fossa tumours. Somatosensory evoked potentials (SSEP) were monitored in all patients, and brain stem auditory evoked potentials (BAEP) in five. While minor changes in BAEP and SSEP parameters were noted in most patients, significant changes occurred in five. Irreversible loss of BAEP in one patient was associated with complete hearing loss postoperatively. Marked, persistent alteration of both BAEP and SSEP was associated with postoperative brainstem dysfunction. No patient with stable BAEP and SSEP at the end of the procedure suffered additional neurological deficit. We conclude that intraoperative SEP monitoring may be valuable in minimizing neural injury during major neurosurgical procedures.

Adult↗

Syringoperitoneal shunt for treatment of cord cavitation.

A series of twenty-nine patients with cord cavitation were treated by syringoperitoneal shunt. Twenty-two of them showed improvement after operation, five were unchanged and two worsened. Operation was performed in patients with post-traumatic cystic myelopathy, idiopathic syringomyelia, intramedullary tumours associated with cysts, and patients who had developed cystic myelopathy in association with spinal arachnoiditis. Pain improved in twenty patients, sensory symptoms and signs in eleven and weakness in ten.

Adolescent↗

Effect of perioperative platelet inhibition on postcarotid endarterectomy mural thrombus formation. Results of a prospective randomized controlled trial using aspirin and dipyridamole in humans.

A prospective randomized double-blind trial was conducted to study the effect of platelet-inhibiting drugs on mural thrombus formation after carotid endarterectomy. Twenty-two patients undergoing carotid endarterectomy were randomly assigned to perioperative administration of an aspirin/dipyridamole combination or a placebo, and the postoperative results were compared. Autologous indium-111-labeled platelets were injected postoperatively, and platelet deposition was measured at the endarterectomy site. It was found that the treated group had a significant reduction in platelet accumulation compared with the placebo group. The results suggest that the perioperative use of aspirin/dipyridamole may reduce the risk of operative stroke and the long-term risk of repeat carotid stenosis.

Aged↗

Perioperative use of somatosensory evoked responses in aneurysm surgery.

Somatosensory evoked potentials have been recorded during 34 operations for intracranial aneurysm. The central conduction time (CCT), the time between the N14 peak (recorded at C-2) and the N20 peak (recorded at the cortex) in response to median nerve stimulation, has been found to be increased by administration of halothane, by brain retraction, and by temporary vascular occlusion in some instances. Increase of CCT to more than 10 msec, or disappearance of the response was associated in two cases with postoperative neurological deficit, neither permanent. In a further case, prolongation of CCT was used as a guide to the repositioning of an imperfectly placed clip on a middle cerebral artery aneurysm. The value of the technique as a perioperative monitoring system is discussed.

Adolescent↗

Pituitary apoplexy associated with a triple bolus test. Case report.

The authors report a case of pituitary apoplexy resulting in bilateral internal carotid artery occlusion, with marked depression of consciousness and hemiplegia. After transsphenoidal tumor decompression, restoration of flow in both carotid arteries was documented angiographically and the patient made an excellent clinical recovery. The unique aspect of this case is that the pituitary apoplexy was apparently precipitated by neuroendocrine manipulation, performed as a preoperative test of pituitary function.

Adenoma↗

Lymphocyte surface phenotypes in Down's syndrome.

The lymphocyte surface phenotypes in the blood of 7 non-institutionalized adults with trisomy-21, and in 10 karyotypically normal control subjects, were analysed by fluorescent microscopy with an OKT series of monoclonal antibodies. Whereas the proportions of OKT3+, OKT4+ and OKT6+ cells were similar in the two groups, the percentages of both OKT8+ and OKT10+ trisomic lymphocytes were significantly higher. The biological implications of these findings with respect to the underlying immunopathology of Down's syndrome are discussed.

Adult↗

Monoclonal antibody-defined T-cell surface phenotypes in human breast milk.

The distribution of T-lymphocyte subsets in human early milk was determined by immunofluorescence analysis of reactivity with monoclonal antibodies of the OKT series. A novel finding was that the T-lymphocyte population in human milk contains both OKT4 (helper/inducer phenotype) and OKT8 (suppressor/cytotoxic phenotype)-positive subsets. The relative ratio of OKT4 to OKT8-positive T-cell subsets in milk, however, was generally higher than that observed for peripheral blood T cells.

Female↗

Serum migration inhibitory activity and monoclonal antibody-defined T-cell phenotypes in patients with acute infectious mononucleosis.

Previous experiments in our laboratory have demonstrated that circulating endogenous leucocyte (migration) inhibitory factor (serum LIF), or a lymphokine with LIF-like activity, may be involved in the impaired cellular immune response observed during the acute phase of the Epstein-Barr virus (EBV) induced infectious mononucleosis (IM). To determine whether serum LIF activity is associated with immunoregulatory IM T-cell subset abnormalities, we analyzed the peripheral blood T-cell populations in a series of acute serum LIF-positive and LIF-negative IM patients by means of T-lymphocyte-specific monoclonal antibodies. Although there was both activation and increase of suppressor/cytotoxic T cells in all IM patients sampled in the acute stage, the relative and absolute numbers of suppressor lymphocytes were found to be significantly higher in those who had LIF activity in their serum. It is postulated that EBV infection can preferentially activate a specific T-cell subpopulation which, in its turn, inhibits the overall host immune response, possibly by a LIF-induced feedback suppression mechanism.

Antibodies, Monoclonal↗

"In vitro" and "in vivo" leukocyte migration inhibitory factor production in acute infectious mononucleosis patients.

Since infectious mononucleosis (IM) mononuclear cells spontaneously release the leukocyte (migration) inhibitory factor (LIF) in culture and since previous experiments in our laboratory have demonstrated that one or more substances with LIF-like activity are detectable in the serum (serum LIF) of young patients with heterophile-positive IM, an investigation was carried out to determine both the in vitro and in vivo LIF production in a series of IM patients sampled during the acute phase of the infection. The observation than only the unstimulated lymphocytes from serum LIF-positive IM patients released LIF in culture suggests that a single active product is involved in the in vitro and in vivo LIF activities observed in Epstein-Barr virus (EBV) infected subjects. The biological implications of this finding with respect to the underlying immunopathology of the EBV IM syndrome are discussed.

Adolescent↗

Peripheral nerve injection injury with steroid agents.

The possible neurotoxic effects of five commonly used steroid agents were examined. Using histologic studies and studies of the microneural circulation, it was found the steroids can indeed cause neurotoxicity. The injection site was critical in effecting injury. Only intrafascicular injection caused damage. The damage produced varied with the agent used. Dexamethasone (Decadron) caused minimal damage, while hydrocortisone (Solu-Cortef) and triamcinolone hexacetonide (Aristospan) caused widespread axonal and myelin degeneration. Disturbance in the blood-nerve barrier correlated with the changes noted on light and electron microscopy, but is thought to be coincidentally and not causally related. In conclusion, it was shown that the intrafascicular injection of commonly used steroid agents had a direct toxic effect on peripheral nerve-fibers and caused a disruption of the blood-nerve barrier. Use of the more toxic agents in the vicinity of peripheral nerves should probably be avoided.

Animals↗

Conduction of sensory action potentials across the posterior fossa in infratentorial space-occupying lesions in man.

Central conduction time following median nerve stimulation has been recorded in 28 patients with infratentorial space occupying lesions. Fourteen of these (50%) showed a prolonged central conduction time, which invariably involved that segment of the conduction time between the dorsal column nuclei generators and the generation site for P15, which we believe to be the upper brain stem or thalamus. Three other cases showed prolongation of the N14-P15 segments though total central conduction time was within normal limits. One case with marked hydrocephalus showed prolongation both before and after the P15 wave. The possible pathophysiology of prolongation of central conduction time in these cases and the possible neural generation site of P15 are discussed.

Brain Neoplasms↗