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Biomedical subjects

B G Benoit

Publications and source records attributed to B G Benoit.

At least 19 recordsLinked to original sources
PubMed1996

Association of pleomorphic xanthoastrocytoma with cortical dysplasia and neuronal tumors. A report of three cases.

BACKGROUND: Several recent publications indicate that pleomorphic xanthoastrocytoma (PXA) may occasionally express ganglionic cell differentiation, linking this type of tumor to other benign, mixed glioneuronal neoplasms. Furthermore, ganglionic tumors and less frequently some benign glial tumors in the central nervous system, could be associated with a variety of mild developmental abnormalities of the cerebral cortex that are classified under the broad term cortical dysplasia. The association of cortical dysplasia with PXA and a neuronal pattern of differentiation has not been reported previously. METHODS: The authors present clinical, radiologic, immunohistochemical, and ultrastructural findings in three patients with cortical dysplasia. The cortical dysplasia was continuous with PXA, displaying an additional component of neuronal cell differentiation. RESULTS: The ages of the patients were 23, 47, and 52 years. Resection of the tumors was predated by temporal lobe seizures by 6 years in 1 patient and by more than 30 years in the others. In all 3 cases, radiologic studies conducted 3-6 years before surgery showed either no abnormality or lesions that were initially nonprogressing. CONCLUSIONS: The longstanding clinical history of seizures and the existence of radiologically documented dormant lesions several years before tumor removal both suggest that PXA in these patients very likely developed in benign hamartomatous cortical lesions or in preexisting cortical dysplasia. The authors' findings, along with the consistent occurrence of PXA in the gray matter in the majority of the reported cases, indicate that these tumors may originate either from a subclass of astrocytes histogenetically and topographically associated with neurons or from multipotential neuroectodermal precursor cells common to neurons and astrocytes.

Adult↗
PubMed1994

Primary intracranial pleomorphic angioleiomyoma--a new morphologic variant. An immunohistochemical and electron microscopic study.

BACKGROUND: Angioleiomyomas usually are benign subcutaneous neoplasms that occur most often in extremities of middle-aged individuals. Very few cases have been described in other locations; none along the neuroaxis. An intracranial example of angioleiomyoma displaying unusual morphologic features not seen in the typical peripheral variants of this tumor is described. METHODS: The tumor was studied with conventional histology, immunohistochemistry with morphometric calculation of proliferation index, immunoelectron microscopy, and DNA flow cytometry. RESULTS: The tumor was composed of large epithelioid and pleomorphic cells filled with intermediate filaments positive for desmin and vimentin. Scattered cells also expressed myosin and muscle-specific actin. Smooth muscle cell differentiation was confirmed by ultrastructural demonstration of subplasmalemmal dense bodies, attachment plaques, and discontinuous basal lamina. The proliferation index with proliferating cell nuclear antigen (PCNA) monoclonal antibody was 75.78%, whereas it was only 4.22% with Ki67 monoclonal antibodies adopted to paraffin material (MIB-1). CONCLUSION: The tumor represents a unique morphologic variant of a pleomorphic angioleiomyoma. Cellular pleomorphism and a strong reaction for PCNA in numerous cells suggested that the lesion was malignant. However, the absence of mitotic figures, a small number of Ki-67-positive cells, a diploic DNA pattern, and a low proliferation index in flow cytometry all supported the concept that this neoplasm represented an unusual histologic variant of benign angiogenic leiomyoma. Encapsulation and demarcation of the surgical specimen and the survival of the patient for more than 4 years without recurrence after resection support this interpretation.

Adult↗
PubMed1994

Adult diastematomyelia.

With modern imaging techniques, various types of spinal dysraphism are being diagnosed in adults with increasing frequency. We report a 42-year-old woman with diastematomyelia whose symptoms characteristically were precipitated by trauma. She exhibited other typical features such as a posterior midline hair patch and vertebral malformations. Metrizamide myelography with computerized tomography showed a bony septum at T11 with a cleft at T9-T11 separating two dural tubes each of which contained a single spinal hemicord. The septum was excised with complete relief of symptoms.

Adult↗
PubMed1992

Phase II study of weekly intravenous menogaril in the treatment of recurrent astrocytomas in adults.

Twenty patients with astrocytomas recurrent after surgery +/- radiation were treated on a phase II protocol of the new anthracycline derivative menogaril 115 mg/m2 administered intravenously once per week. Sixteen patients were evaluable for treatment efficacy. No patient achieved a major therapeutic response. Three patients (19%) had stable disease for greater than 8 weeks, including one who showed minor evidence of tumor regression, but less than 50%. Thirteen patients failed. Treatment was well tolerated. One patient developed granulocytopenia, while none developed thrombocytopenia. Four patients required an interruption in their treatment for one to two weeks because of development of granulocytopenia (one patient) or other reasons. Other toxic effects included arm vein phlebitis and skin irritation, skin discoloration of the infused arm, mild to moderate nausea and vomiting, diarrhea, stomatitis, and a fatal central venous catheter infection. Despite the fact that menogaril appeared to have therapeutic activity against recurrent astrocytomas in our phase I studies, we could not document any activity in this phase II study.

Adult↗
PubMed1992

Suprasellar xanthomatous Rathke's cleft cyst.

A case of a symptomatic suprasellar Rathke's cleft cyst in a 35-year-old woman is presented. The cyst wall and contents showed large collections of xanthomatous cells. With the exception of a few pituitary hormone-positive cells, immunohistochemical and ultrastructural features of the lining epithelium in this case of Rathke's cleft cyst were indistinguishable from colloid cysts of the third ventricle with similar secondary changes.

Adult↗
PubMed1992

Phase I study of intracarotid administration of carboplatin.

Fifteen patients were treated in a Phase I study of intracarotid carboplatin (200-400 mg/m2) in 5% dextrose and water infused over 15 to 30 minutes through a transfemoral catheter with a 0.2-micron inline filter. This study was done because intravenous carboplatin has less neurotoxicity than cisplatin and is active against brain tumors. Eleven men and four women ranging in age from 37 to 72 years (median, 59 years) were treated. The Eastern Cooperative Oncology Group performance status was 1 in 3, 2 in 4, and 3-4 in 8 patients. Eight patients had one to three previous chemotherapy regimens; previous radiotherapy had failed in 13 patients. The response of patients in the Phase I study follows: glioblastoma, 6 failed; not evaluated because of early death from pulmonary embolus, 1; recurrent Grade II and III glioma, 1 stable (minor response with neurologic improvement) and 2 failed; malignant oligodendroglioma, 1 failed; brain metastases from nonsmall cell lung cancer, 1 partial remission, 1 stable (minor response), and 1 failed; brain metastases from unknown primary, 1 stable (minor response with neurological improvement). Median survival was 9 weeks. Nausea was mild to moderate. One patient had granulocytopenia, and 2 had thrombocytopenia (mild). At 200 mg/m2 (2 patients), 1 had a focal seizure. At 300 mg/m2 (9 patients), 2 with abnormally small arteries had severe pain early in the treatment and posttreatment ipsilateral conjunctival edema, decreased vision, and cerebral edema (with partially reversible increased hemiparesis); 1 other had mild decrease in ipsilateral vision and 1 had transient aphasia on removal of the catheter (possibly the result of a vascular spasm).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Central neurogenic tumours of the thoracic region.

Of special concern in the management of neurogenic tumours arising in the thorax is spinal-cord compression resulting from either intraspinal lesions or vertebral-body destruction and collapse. A review of 16 cases disclosed three dumbbell tumours, six intrathoracic tumours, one case of neurofibromatosis with multiple intraspinal neurogenic tumours, two malignant neurogenic tumours with vertebral-body destruction causing spinal-cord compression and four foraminal lesions with central intraspinal (extradural) extension. There were 3 men and 13 women, ranging in age at the time of operation from 37 to 79 years. Three patients, of the six with intrathoracic tumours, were asymptomatic; the remaining 13 had preoperative symptoms ranging in duration from 3 weeks to 12 months (average, 9 months). Back pain with intercostal neuralgia was present in eight patients and neurologic signs were present in six patients. A routine chest radiograph was abnormal in 10 patients, and x-rays of the thoracic spine were abnormal in 4 of the other 6 patients. The tumour was excised surgically in all patients. Complications developed postoperatively in two patients: one had Horner's syndrome, transient paraparesis and bleeding; the other had a small subarachnoid-cutaneous fistula. The authors conclude that dumbbell neurogenic tumours and those causing vertebral-body destruction and collapse demand a multidisciplinary one-stage surgical approach. If the lesion is malignant and resection is not complete, radiotherapy or chemotherapy is necessary.

Adult↗
PubMed1988

Multiple noncontiguous fractures of the cervical spine.

Multiple noncontiguous fracture-subluxations of the cervical spine are fractures and subluxations separated by at least one normal intervening cervical vertebra. A review of all 66 consecutive cervical spine fractures treated by the Division of Neurosurgery at the University of Ottawa during 26 consecutive months revealed six such cases (9%). These injuries are more common than previously recognized. Special consideration is required in their treatment because of the presence of a mobile intermediate segment in some of these patients.

Accidents, Traffic↗
PubMed1988

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↗
PubMed1987

Metrizamide CT scanning in spinal nerve root cysts.

Two cases of lumbosacral root cysts of different etiology are reported. Their specific radiographic features are described using the combined technique of metrizamide myelography followed by computerized tomography of the spine. The terminology of intraspinal cysts is reviewed and their distinguishing features discussed.

Cysts↗
PubMed1987

Interhemispheric subdural hematoma.

Although relatively uncommon, interhemispheric subdural hematoma (ISDH) occurs more frequently than was suspected before the advent of computerized tomographic (CT) scanning. When its mass is sufficiently large to compress the medial cerebral hemisphere, specific focal neurological abnormalities may occur. These include weakness of the contralateral leg, or contralateral hemiparesis with the leg being weaker than the arm. On the unenhanced CT scan ISDH is seen as a crescent shaped, midline hyperdensity. Treatment is dictated by the clinical course. Evacuation of the hematoma by parasagittal craniotomy is recommended if the symptoms are pronounced.

Aged↗
PubMed1987

Intraarterial mitomycin-C for recurrent brain metastases.

Fifteen consenting patients with brain metastases recurrent after cranial irradiation were treated with intraarterial mitomycin-C, 15 mg/m2, administered in a total final volume of 100 ml 0.45% saline over 20 min through a transfemoral catheter with a 0.2-mu in-line filter. There were 2 early deaths (one probably drug-related). Of the 13 evaluable patients, 6 (46%) responded, with both computed tomography (CT) scan and neurological improvement. Median response duration was 25 weeks, and median survival of all 15 patients was 17 weeks. Neurological, ocular, and local skin toxicity were dose-limiting. The degree of toxicity was comparable to that we have noted with other intracarotid regimens, and it appears to be less toxic when infused into the vertebral artery than are most other drugs (although experience is still limited and caution still needs to be exercised). We do not recommend that this replace or be added to cranial irradiation as front-line treatment of brain metastases, but we feel that it is an effective and reasonably well-tolerated regimen for treatment of brain metastases that have recurred after cranial irradiation. We are currently initiating studies of intraarterial mitomycin-C combined with intraarterial cisplatin and teniposide (VM-26) as treatment for recurrent brain metastases.

Adolescent↗
PubMed1987

Neurolysis combined with the application of a silastic envelope for ulnar nerve entrapment at the elbow.

Sixty-six patients with ulnar nerve entrapment at the elbow underwent neurolysis and the application of a Silastic envelope in an attempt to prevent postoperative scarring and recurrence of symptoms. All patients were evaluated pre- and postoperatively using a numerical scoring system that included clinical, motor, and sensory evaluation as well as nerve conduction studies. The Silastic material was well tolerated in the 70 cases. The overall 66% score improvement was more closely related to clinical relief (64%) than to improvement in motor conduction velocities (45%). Our 10-year experience indicates that ulnar neurolysis with Silastic envelope interposition is a safe surgical method of treatment for ulnar nerve entrapment at the elbow.

Adult↗
PubMed1987

Spontaneous carotid-cavernous fistula and multiple arterial dissections in type IV Ehlers-Danlos syndrome. Case report.

A 43-year-old woman without phenotypic expression of Ehlers-Danlos syndrome developed a spontaneous unilateral carotid-cavernous fistula (CCF). Attempts at balloon occlusion of the CCF were unsuccessful, and caused multiple arterial dissections and lacerations eventually leading to massive retroperitoneal hemorrhage and death. The CCF was demonstrated during postmortem studies. In addition, the patient had independent dissections of the internal carotid artery at the site of the fistula and an intracavernous aneurysm of the contralateral internal carotid artery. Despite widespread dissections, the major arteries showed only mild histological abnormalities. Morphometric analysis of collagen from the aorta revealed an increase in large-sized fibers, consistent with deficiency of Type III collagen.

Adult↗
PubMed1987

Intraspinal cysts: a classification and literature review.

Advances in radiologic technology have allowed the identification of a variety of cystic lesions of spinal nerve roots. Failure to appreciate the different characteristics of these cysts has led to a confusion in terminology, with different terms often being used to describe the same lesion. In an attempt at clarification, the literature is reviewed and a simplified classification of spinal cysts presented. The distinguishing features of each type of cyst, its investigation, and appropriate treatment are discussed.

Cysts↗