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C M Loftus

Publications and source records attributed to C M Loftus.

68 records · Page 4Linked to original sources
PubMed1987

Measurement of regional cerebral blood flow and somatosensory evoked potentials in a canine model of hemispheric ischemia.

Regional cerebral blood flow (rCBF) was studied using the radiolabeled microsphere technique in a canine model of hemispheric ischemia that others have previously examined morphologically with carbon perfusion. It was our goal to ascertain whether this ischemic model, which involves easily accessible occlusions of the ipsilateral circle of Willis, could produce reproducible and significant reduction of hemispheric cerebral blood flow. Seven animals underwent the surgical procedure with measurements of rCBF at base line, after arterial microdissection and brain retraction only, and finally after creation of the lesion. Simultaneous somatosensory evoked potential recordings were also obtained. Bilateral symmetrical flow decreases were referable to anesthetic normalization and maintenance alone before creation of the lesion. The arterial occlusions, however, produced further significant decreases in flow on the ipsilateral side only, sparing all contralateral structures and sparing the brain stem and cerebellum bilaterally. Evoked responses, which had shown no changes in latency or amplitude after dissection and retraction procedures, were completely abolished 15 minutes after the arterial occlusion. Control animals that underwent surgical positioning and anesthesia alone did not show concomitant decreases is rCBF. This model of open craniotomy and direct vascular occlusion is suitable for studies of cerebral ischemia where the therapeutic intervention proposed (such as cerebral revascularization) involves similar surgical manipulations. By this method, a standard and reproducible ischemic lesion is achieved through the surgical field without the need for exposure of the basilar artery.

Animals↗
PubMed1987

Effects of preexisting bypass graft on rCBF and SSEP's following acute stroke in dogs.

Regional cerebral blood flow (rCBF) was measured with radiolabeled microspheres in a canine model of superficial temporal artery-middle cerebral artery (STA-MCA) bypass and acute ischemia. Ischemic zone flows in seven dogs with the bypass first closed and then open showed no significant contribution of bypass flow in the intact vascular system. Following acute proximal occlusion, rCBF was preserved by bypass flow. A significant flow decrease ensued when the bypass was then clipped, confirming the adequacy of the lesion and the protective effect of the bypass. Reopening the bypass after 15 minutes of ischemia restored 76% of the previous flow. This was a significant increase from the global ischemia values, and was not statistically different from preocclusive values. Preocclusion somatosensory evoked potentials (SSEP's) in these animals showed a consistent biphasic wave at 8 to 10 msec after stimulation. This wave, with some decrease in amplitude, was preserved by bypass flow following creation of the arterial lesion. Bypass clipping abolished these ipsilateral SSEP's. Variable return of SSEP's occurred following reopening of the graft, but the recordings never reached preischemic amplitudes. This experimental study shows that, in this model, a prophylactic bypass subjected to immediate demand (with no time for "maturation") can adequately augment cortical rCBF and is superior to delayed revascularization. The data lend theoretical support to placement of a prophylactic STA-MCA bypass prior to elective carotid artery sacrifice or in surgery where the risk of acute vascular injury is high.

Animals↗
PubMed1986

Motilin-related immunoreactivity in mammalian adenohypophysis.

Motilin, a gut peptide recently demonstrated in the mammalian brain and anterior pituitary, was localized immunocytochemically in rat, guinea pig, and human anterior pituitary glands with two antisera to synthetic porcine motilin. Adjacent sections of normal glands were immunostained for motilin, growth hormone, and prolactin reactivity. Motilin reactivity was consistently seen in somatotrophic regions of the mammalian glands and in many instances was colocalized in individual somatotrophs traced in adjacent sections stained for growth hormone. There was no motilin activity discerned in prolactin-secreting regions of the gland. These studies reinforce the close relationship of motilin or a motilin-like peptide with growth hormone in normal somatotrophs. Further anatomical and in vitro studies with tumor material will be useful in elucidating the physiological relationship of motilin to growth hormone.

Animals↗
PubMed1986

Distal cervical carotid dissection after carotid endarterectomy: a complication of indwelling shunt?

Technical factors and surgical techniques in carotid endarterectomy remain a controversial subject. The use of an indwelling arterial shunt has theoretical advantages in assuring intraoperative hemispheric perfusion and affording a more relaxed surgical environment. There has been little clinical demonstration, however, of superior results with carotid shunting. Although champions of routine shunting argue that it is a benign protective intervention, the possibilities of distal embolization or intimal disruption exist. The authors report a case of cervical carotid dissection far distal to the operative site that they postulate resulted from intimal disruption after routine shunt placement. This devastating complication from an otherwise benign procedure prompts reconsideration of the benefits and risks of routine shunt placement.

Aged↗
PubMed1986

Incidence and etiology of intracerebral hemorrhage following carotid endarterectomy.

In a consecutive series of 1930 carotid endarterectomies there were eight cases of postoperative intracerebral hemorrhage. One of these patients was operated on 2 weeks following cerebral infarction and had severe uncontrollable hypertension after surgery. A second patient had an intraoperative embolus and bled while fully heparinized on the 3rd postoperative day. Only one patient in the series bled into an area of documented cerebral infarction. The remainder of the cases represented hemorrhage into essentially normal brain. Seven of the eight patients with intracerebral hemorrhage had high-grade internal carotid artery stenosis preoperatively. Although several factors have contributed to the brain hemorrhages in this series of patients, postoperative cerebral hyperperfusion which often follows endarterectomy may have played an important role. Defective cerebrovascular autoregulation in chronically ischemic brain regions may predispose patients to intracerebral hemorrhage after removal of a high-grade stenosis of the internal carotid artery.

Aged↗
PubMed1985

Cystic supratentorial gliomas: natural history and evaluation of modes of surgical therapy.

The management of cystic supratentorial gliomas is hampered by lack of documentation of the natural history of these lesions and by a lack of evaluation of modes of surgical therapy. We analyzed these factors in 25 patients with solitary cysts operated upon over a 20-year period. Two distinctive patterns of symptoms were seen: short duration (increased pressure and hemiparesis), most often heralding a malignant lesion, and long duration (commonly seizure disorder), associated more often with a benign pathological condition. Large solitary cysts were found in tumors of all histological grades. Surgical procedures included extirpation, biopsy/partial resection, cyst communication to ventricle or marsupialization, burr hole aspiration, aspiration via an indwelling reservoir, and cyst-peritoneal shunting. Radiotherapy, given in all cases, did not prevent cyst recurrence. Of the 25 patients, 76% are alive and remain cyst free at follow-up intervals of 1 to 16 years (mean, 3.2). Five patients died from their tumors, with a mean survival of 33 months after decompression. In 7 of 8 patients with cysts largely or entirely within the basal ganglia or thalamus, successful operative cyst control was achieved. Patients with solitary cystic gliomas seem to have a favorable prognosis, and vigorous efforts to control cyst recurrence and limit disability are warranted. Analysis of our data suggests that craniotomy for tumor resection, cyst decompression, and tissue diagnosis is the initial procedure of choice. Cyst recurrence without major solid tumor should be controlled by computed tomography-guided tap or shunt drainage. Reexploration is indicated when cyst reaccumulation is accompanied by clear regrowth of a solid component.

Adolescent↗
PubMed1984

Hemangioblastoma of the third ventricle.

A case of intraventricular hemangioblastoma not associated with von Hippel-Lindau disease is presented. Only one other case of intraventricular hemangioblastoma has been reported. The literature on supratentorial hemangioblastomas is reviewed, and the problems of histological identification of such lesions are discussed.

Brain↗
PubMed1983

Seizures during the immediate postoperative period.

Twenty-three of 538 patients undergoing elective craniotomy had a seizure within 24 hours after operation. The lesion had been located extra-axially in 15 patients and intra-axially in 8 patients. Except for 1 patient who had a parietal craniotomy for an arteriovenous malformation, all patients had a frontal or temporal exposure. Only 5 patients had a previous history of seizures. Adequate levels of anticonvulsant medication were not present in 19 of the 23 patients before operation. No major postoperative metabolic abnormalities were noted in any of the 23 patients. Thirteen of the 23 patients underwent computed tomography to evaluate the etiology of their seizures; none had a significant intracerebral or extracerebral hematoma. This review suggests that an early postoperative seizure is unlikely to be due to a postoperative hematoma or to metabolic abnormality. The most common association in this series was with inadequate anticonvulsant prophylaxis. An approach to postoperative seizure prophylaxis and management is presented.

Brain↗
PubMed1983

Management of plasmacytomas of the spine.

Epidural plasmacytoma often reflects systemic myelomatous involvement and usually has a poor prognosis. The isolated spinal plasmacytoma, however, is a lesion with the potential for long term remission or even cure in some cases. We report six patients with isolated plasmacytoma of the low thoracic or lumbar region, all of whom presented with pain and minimal neurological deficits. Our approach to such cases included a complete medical work-up and radiographic definition of the lesion with a bone scan, a skeletal survey, myelography, computed tomography, and, in some instances, spinal angiography. All of these patients underwent laminectomy and spinal fusion with autologous bone and Harrington rods. There was no morbidity associated with the procedure, which was designed to prevent possible collapse during subsequent radiotherapy or chemotherapy, with its attendant potential for neurological catastrophe. Several patients have developed systemic involvement necessitating chemotherapy, but in follow-up extending now to 4 years all patients remain ambulatory and pain-free. We are encouraged by the potential for symptomatic relief and neurological improvement of patients with isolated spinal plasmacytomas who are treated with an aggressive medical and surgical approach.

Adult↗
PubMed1983

Current status of carotid endarterectomy for atheromatous disease.

The authors discuss the indications for both elective and emergency carotid endarterectomy. Reports on the surgical treatment of asymptomatic bruit and contralateral carotid stenosis are reviewed. The results of endarterectomy for symptomatic carotid disease, including transient ischemic attacks, acute neurological deficit, and complete carotid occlusion, are discussed. The complications and risks of carotid surgery are also presented.

Carotid Artery Diseases↗
PubMed1980

Solitary osteochondroma of T4 with thoracic cord compression.

A patient with a solitary osteochondroma of T4 presented with a five-year history of back pain and progressive paraparesis. Conventional and computed tomography delineated the tumor, which was totally removed via a thoracic laminectomy. Osteochondroma is an unusual cause of spinal cord compression.

Adult↗