Electroencephalographic monitoring of cerebral function during asystole and successful cardiopulmonary resuscitation.
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Aged↗
Biomedical subjects
F B Meyer
Publications and source records attributed to F B Meyer.
Sarcomatous transformation in cranial chordoma.
In a study of 52 patients with cranial chordoma treated at the Mayo Clinic over a 19-year period (1966-1984), two tumors showed anaplastic features, both de novo, i.e., unassociated with prior irradiation. The incidence of anaplastic transformation was thus 4%. Immunohistochemistry showed the mixed mesenchymal-epithelial phenotype typical of chordoma in portions of both tumors, but loss of reactivity for keratin and epithelial membrane antigen was noted in anaplastic components. The study indicates that sarcomatous change in chordoma is a rare event that may occur de novo and is associated with the loss of immunophenotypic features of epithelial differentiation.
Biomarkers, Tumor↗
Cerebral protection during aneurysm surgery with isoflurane anesthesia. Technical note.
A strategy for intraoperative cerebral protection is described in which intraoperative electroencephalography is used to titrate the level of inspired isoflurane given for anesthesia to obtain isoelectricity prior to temporary vessel occlusion during repair of difficult aneurysms. During temporary vessel occlusion, arterial blood pressure is maintained or increased with an inotropic or vasopressor agent. After clipping of the aneurysm, the concentration of isoflurane is reduced to allow the patient to awaken in the operating room for early postoperative neurological examination. The combination of a high concentration of isoflurane, temporary vessel occlusion, and maintenance of arterial blood pressure may be a useful protective regimen during neurovascular procedures.
Anesthesia, General↗
Effects of intermittent reperfusion during temporal focal ischemia.
There is controversy regarding the role of intermittent reperfusion employed as a cerebroprotective measure when temporary arterial occlusion is necessary during repair of difficult aneurysms. The intraluminal suture middle cerebral artery (MCA) occlusion technique was used in 23 Wistar rats under barbiturate anesthesia to induce 60, 90, or 120 minutes of uninterrupted MCA occlusion. The total infarcted areas obtained were compared to those occurring in 27 animals subjected to identical cumulative ischemic periods but with 5 minutes of reperfusion after every 10-minute ischemic period. The mean total infarcted areas in the groups with 60-minute (1.8 +/- 0.89 sq mm), 90-minute (1.08 +/- 1.02 sq mm), and 120-minute (8.72 +/- 5.89 sq mm) intermittent reperfusion were significantly smaller than those occurring in the 60-minute (12.02 +/- 3.10 sq mm), 90-minute (11.54 +/- 2.68 sq mm), or 120-minute (30.43 +/- 6.51 sq mm) control groups, respectively (p < 0.05). Furthermore, there was no difference in the occurrence of blood-brain barrier breakdown, intraparenchymal hemorrhage, hemispheric edema, or seizures between control and intermittent reperfusion groups. The results support the hypothesis that intermittent reperfusion is beneficial if vessel occlusion is required during aneurysm repair.
Animals↗
Ventriculoatrial shunt distal catheter placement using transesophageal echocardiography: technical note.
Accurate placement of the distal end of a ventriculoatrial shunt at the cavo-atrial junction is important for long-term shunt function as well as for avoiding cardiac arrhythmias, thrombus formation, and damage to myocardial tissue. Standard methods of intraoperative localization, including chest x-ray, pressure measurements, and electrocardiogram recording, can be inaccurate. By using intraoperative transesophageal echocardiography, the distal end of the catheter can be localized to the cavo-atrial junction.
Adult↗
Basic fibroblast growth factor promotes in vivo cerebral angiogenesis in chronic forebrain ischemia.
This experiment was designed to determine if intraventricular administration of basic fibroblast growth factor (bFGF) could promote cerebral angiogenesis in a model of mild chronic forebrain ischemia. Wistar rats underwent bilateral carotid artery ligation. Animals received intraventricular injections of bFGF every 4 days for 28 days. Basic fibroblast growth factor caused a significant dose-dependent increase in capillary density compared to ischemic controls in all regions examined. These results support the hypothesis that chronic intraventricular administration of bFGF induces in vivo cerebral angiogenesis.
Animals↗
Corticotropin releasing factor antagonist reduces ischemic hippocampal neuronal injury.
This experiment tested the hypothesis that corticotropin-releasing factor (CRF) contributes to hippocampal ischemic injury. The antagonist to CRF (alpha-CRF) was administered intraventricularly 15 min prior to 10 min of transient forebrain ischemia in the Wistar rat. alpha-CRF demonstrated a neuroprotective effect in a dose-dependent manner most notable in CA1. There was also an increase in postischemic EEG recovery. It is postulated that CRF contributes to hippocampal ischemic injury through increased neuronal activity.
Animals↗
Magnetic resonance imaging-based volume studies in temporal lobe epilepsy: pathological correlations.
We performed a prospective study correlating magnetic resonance imaging volume measurements of the hippocampal formation with histopathology in 24 patients with intractable partial epilepsy who subsequently underwent an anterior temporal lobectomy for their seizure disorder. Patients with mass lesions verified pathologically were excluded from this study. In 71% of patients, quantitative hippocampal formation atrophy correctly lateralized the temporal lobe of seizure origin; in 29%, the volume study was indeterminant. The severity of the pathological alterations in the hippocampus correlated with the hippocampal formation volume determination. Mesial temporal sclerosis was identified in the surgically excised temporal lobe in 15 patients. The magnetic resonance imaging volume studies indicated hippocampal atrophy in the temporal lobe resected in 14 of the 15 patients. Magnetic resonance imaging-based volume measurements of the hippocampal formation increase the diagnostic yield of magnetic resonance imaging scanning in patients with intractable partial epilepsy related to mesial temporal sclerosis.
Adolescent↗
The treatable dementia of Sjögren's syndrome.
Progressive dementia developed during a 15-month period in a 56-year-old woman with serologically and clinically documented primary Sjögren's syndrome. Findings from magnetic resonance imaging and angiography were normal, but a brain biopsy disclosed perivascular lymphocytic inflammation in leptomeningeal and parenchymal vessels. Treatment with high-dose corticosteroids produced rapid and nearly complete resolution of the dementia.
Alzheimer Disease↗
Carotid endarterectomy in elderly patients.
Between 1971 and 1989, 749 carotid endarterectomies were performed at our institution for symptomatic carotid occlusive disease in patients older than 70 years of age. Of these procedures, 693 were done in patients 71 through 80 years of age, and 56 were done in patients between the ages of 81 and 90 years. The neurologic morbidity and perioperative mortality in the former group were 2.9% and 1.4%, respectively, whereas in the latter group the corresponding values were 5.4% and 0%, respectively. For the entire group, the neurologic morbidity was 3.1% and the mortality was 1.3%. Of the 23 new postoperative neurologic deficits, 19 (83%) occurred in high-risk patients with severe preoperative neurologic or medical risks, and 14 (61%) of these deficits were minor. In selected elderly patients with symptomatic hemodynamically significant carotid occlusive disease, endarterectomy seems to be a safe procedure that is associated with acceptably low perioperative morbidity and mortality.
Age Factors↗
Head injury and the use of baby walkers: a continuing problem.
STUDY OBJECTIVE: To determine the frequency of baby walker use as a contributing factor in head injuries in children less than 2 years old. DESIGN: Retrospective clinical review. SETTING: Urban Level I trauma center and multispecialty clinic. TYPE OF PARTICIPANTS: All children less than 2 years old who were evaluated for a head injury during a three-year period. MEASUREMENTS AND MAIN RESULTS: 129 patients' cases were reviewed. Walker-related injuries occurred in 19 of 129 patients (14.7%). This represents the third most common mechanism of injury in this age group. Mean patient age at the time of injury was 8.7 months. Of the 19 accidents involving walkers, 18 (94.7%) involved falling down stairs. Nine children (47.4% of all walker-related injuries) suffered fractures of the cranial vault. No patients required surgical intervention, although one required treatment for post-traumatic meningitis. CONCLUSION: Baby walkers continue to be a frequent cause of head injury in this age group, and further efforts must be made to deal with these preventable injuries.
Accidental Falls↗
Symptomatic subependymoma: a clinicopathological and flow cytometric study.
Twenty-one intracranial subependymomas were reviewed with regard to presentation, diagnosis, operative findings, and long-term follow-up data. The histopathological features were critically reviewed, and deoxyribunucleic acid analysis was performed by flow cytometry. The patients' mean age was 48.5 years (range 32 to 72 years). In 14 cases the tumor was located in the fourth ventricle, in six within a lateral ventricle, and in one in the third ventricle with extension into the lateral ventricle. Radiographic characteristics included isodensity with minimal enhancement on computerized tomography, frequent dystrophic calcification, and isointensity on T1-weighted or slight hyperintensity on T2-weighted magnetic resonance images. The predominant histological features in all cases were those of classic subependymoma. Nonetheless, pathological examination showed a minor (less than 20%) ependymoma component in five cases, significant cytological atypia in seven, mitoses in 11, endothelial prominence in four, and focal hemorrhage-associated necrosis in two. Flow cytometry revealed a diploid pattern in 12 patients, tetraploidy in two, and aneuploidy in one. Two patients died in the perioperative period. Of the remaining 19, 12 underwent gross total resection (two of whom received postoperative irradiation) and seven underwent subtotal resection (five of whom received irradiation). None of the 12 non-irradiated patients developed tumor progression or died of direct tumor-related causes. Of the seven irradiated patients, follow-up imaging studies demonstrated their tumors to be radioresponsive, particularly with doses of 5000 cGy or greater. Despite the presence of cytological atypia and mitotic activity in the majority of cases, the prognostic effects of such factors as tumor location and the extent of surgical resection outweighed those of the standard histopathological parameters. Routine postoperative irradiation is not recommended, but should be reserved for cases with a symptomatic residual or recurrent subependymomas following surgery.
Adult↗
"Angioglioma" and the arteriovenous malformation-glioma association.
The term "angioglioma" denotes a highly vascular glioma, most of which are low-grade lesions associated with a favorable prognosis. The authors encountered an example of this pathology, a cystic oligodendroglioma associated with prominent vasculature which both clinically and histologically mimicked an occult arteriovenous malformation (AVM). This case and reports of the association of AVM and glioma prompted a histological review of 1034 surgically resected AVM's, both angiographically occult and visible, among which no oligodendroglial or astrocytic forms of "angioglioma" were found. Eight cases were observed, however, wherein oligodendroglial cells were increased in number within or about the malformation. Two basic histological patterns of oligodendroglial cell excess were seen; one appeared to be malformative in nature with abnormal disposition of oligodendroglial cells being an integral part of the AVM, whereas in the other an apparent increase in cellularity seemed the result of chronic ischemia with condensation of white matter. It appeared that the areas of increased oligodendrocyte content seen in association with AVM are non-neoplastic lesions that exhibit two rather distinct histological patterns of differing origin. In an effort to determine the frequency of "angioglioma," the authors examined Tissue Registry data for several glioma groups in which highly vascular examples are prone to occur. Tumors selected for study included 104 cerebellar-type (pilocytic) astrocytomas, 82 oligodendrogliomas, and 51 supratentorial pilocytic astrocytomas. Histological hypervascularity mimicking a vascular malformation (that is, an "angioglioma") was encountered in 5%, 4%, and 12% of the cases, respectively. Based upon clinical, radiological, and pathological reviews of these cases, as well as a careful review of the literature, it was concluded that 1) "angiogliomas" are neither rare nor represent a distinct clinicopathological entity; 2) in histological but not necessarily angiographic surgical terms, they represent simply highly vascular gliomas, usually of low grade; and 3) the clinicopathological and angiographic features as well as the prognosis of such lesions do not differ from those of similar gliomas without angioma-like vasculature. Finally, "angiogliomas" must not be confused with gliomas of high-grade malignancy which, due to neovascularity, may be highly vascular at angiography and at surgery.
Adolescent↗
Giant intracranial aneurysms.
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Adolescent↗
Intraventricular infusion of HBGF-2 promotes cerebral angiogenesis in Wistar rat.
The angiogenic effects of chronic intraventricular infusion of basic fibroblastic growth factor (HBGF-2) were assessed in the Wistar rat cerebral cortex. HBGF-2 increased both capillary density and area of perfused vasculature without altering capillary diameters in periventricular cortex adjacent to the site of infusion. Although it has been demonstrated that growth factors can cause brain endothelial proliferation in vitro, this is the first report of in vivo cerebral angiogenesis.
Animals↗
Cerebrospinal fluid physiology and the management of increased intracranial pressure.
Increased intracranial pressure can result in irreversible injury to the central nervous system. Among the many functions of the cerebrospinal fluid, it provides protection against acute changes in venous and arterial blood pressure or impact pressure. Nevertheless, trauma, tumors, infections, neurosurgical procedures, and other factors can cause increased intracranial pressure. Both surgical and nonsurgical therapeutic modalities can be used in the management of increased intracranial pressure attributable to traumatic and nontraumatic causes. In patients with cerebral injury and increased intracranial pressure, monitoring of the intracranial pressure can provide an objective measure of the response to therapy and the pressure dynamics. Intraventricular, intraparenchymal, subarachnoid, and epidural sites can be used for monitoring, and the advantages and disadvantages of the various devices available are discussed. With the proper understanding of the physiologic features of the cerebrospinal fluid, the physician can apply the management principles reviewed herein to minimize damage from intracranial hypertension.
Absorption↗
The novel dihydronaphthyridine Ca2+ channel blocker CI-951 improves CBF, brain pHi, and EEG recovery in focal cerebral ischemia.
The effects of the novel dihydronaphthyridine Ca2+ antagonist CI-951 on focal cerebral ischemia were assessed during MCA occlusion in 30 white New Zealand rabbits under 1.0% halothane anesthesia. In vivo brain pHi and focal CBF were measured with umbelliferone fluorescence. Baseline normocapnic brain pHi and CBF were 7.02 +/- 0.02 and 48.4 +/- 2.9 ml/100 g/min, respectively. In the severe ischemic regions, 15 min postocclusion brain pHi and CBF were 6.62 +/- 0.04 and 14.4 +/- 0.7 ml/100 g/min in controls vs. 6.60 +/- 0.02 and 12.9 +/- 2.3 ml/100 g/min, respectively, in animals destined to receive CI-951. Twenty minutes after MCA occlusion, CI-951 was administered at 0.5 microgram/kg/min and brain pHi and CBF were determined in both regions of severe and moderate ischemia for 4 h postocclusion. Control severe ischemic sites demonstrated no significant improvement in brain pHi and only mild increases in CBF over the next 4 h. CI-951 caused significant improvement in both of these parameters. Postocclusion 4 h brain pHi and CBF measured 6.69 +/- 0.04 and 18.5 +/- 3.2 ml/100 g/min in controls vs. 7.01 +/- 0.04 and 41.7 +/- 5.3 ml/100 g/min, respectively, in CI-951 animals (p less than 0.001). Similar improvements were observed in moderate ischemic sites. In animals that demonstrated postocclusion EEG attenuation, 75% of CI-951 animals had EEG recovery as compared to 18% in controls. CI-951 may be a useful therapeutic agent for focal cerebral ischemia if histological and outcome studies verify these data.
Animals↗
MK-801 attenuates capillary bed compression and hypoperfusion following incomplete focal cerebral ischemia.
The effects of the N-methyl-D-aspartate (NMDA) antagonist MK-801 on capillary beds and CBF following 1 h of transient incomplete focal cerebral ischemia were studied by examining 133Xe CBF, capillary diameter, and area of perfused vasculature. Capillary diameter increased from a control of 5.24 +/- 0.37 to 8.62 +/- 0.57 microns (p less than 0.001) and area of perfused vasculature from 20,943 +/- 1,151 to 30,442 +/- 1,691 microns2/x 10 magnification field (p less than 0.001) with MK-801 1.0 mg/kg administered 30 min prior to ischemia. After flow restoration in control animals, there was a relative hypoperfusion with eventual normalization of CBF over 60 min. Alternatively, in MK-801 1.0 mg/kg animals, there was rapid normalization of CBF upon flow restoration without the postischemic hypoperfusion observed in controls. On histological analysis, there was consistently less neuronal edema in MK-801-treated animals. These results support the hypothesis that hypoperfusion following incomplete focal cerebral ischemia may be due in part to NMDA-mediated cellular edema with subsequent extravascular capillary bed compression.
Animals↗