摘要:

&NA;Intimal accumulation of indium‐111‐labeled platelets in the middle cerebral arteries was examined in two different models of experimental subarachnoid hemorrhage (SAH) in the cat. SAH was produced in 7 subjects by a transorbital rupture of the right middle cerebral artery (RMCA) and in 10 subjects by the transorbital cisternal injection of 2 ml of autologous arterial blood around the RMCA. Animals in both experimental groups were sacrificed at 2, 4, 24, and 48 hours after SAH. The radioactivity (in counts per minute) of the RMCA segment was divided by that of the left middle cerebral artery (LMCA) to produce a radioactivity ratio (RMCA/LMCA). This radioactivity ratio was determined for each animal and was scored as positive if it was 1.25 or greater, and as negative if it was less than 1.25. The scores derived from the radioactivity ratios in both experimental SAH groups were mostly positive (86 and 70%, respectively) and were significantly different (P< 0.05) from those of intact controls (n = 7) or sham‐operated controls (n = 5; n = 4). There was, however, no significant difference (P= 0.35) between the scores of the two experimental groups in the first 48 hours after SAH. The results indicate that subarachnoid blood placed upon the adventitial surface of intact cerebral arteries activates platelet aggregation to a degree comparable to that which occurs after mechanical vessel rupture in the acute stages of SAH. We suggest that the noxious agents responsible for arterial injury and subsequent intimal platelet aggregation after SAH exert their influence primarily from the abluminal surface of the cerebral artery. (Neurosurgery24:487‐490, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;To test the safety of a large intrathecal dose of human recombinant tissue plasminogen activator (rt‐PA), 6 cynomolgous monkeys were given 10 mg of rt‐PA (mean, 2.7 mg/kg) through an Ommaya reservoir after craniectomy and dissection of the basal cisterns. Bleeding occurred briefly at the incision in 2 animals; otherwise the clinical condition of all 6 remained normal throughout the postoperative period. Systemic fibrinolysis did not occur, and gross and microscopic examination of the brain and meninges revealed no abnormality. Next, we evaluated the efficacy of unilateral administration of rt‐PA suspension (0.5 mg) plus slow‐release gel rt‐PA (1.25 mg) in lysing a bilateral subarachnoid clot and preventing vasospasm in a randomized, placebo‐controlled trial. Sixteen monkeys were divided randomly into 2 equal groups, each of which underwent baseline cerebral angiography, followed by frontotemporal craniectomy and induction of subarachnoid hemorrhage on the left side and then on the right. Before closure on the right side either rt‐PA or an equal volume of placebo was injected into the subarachnoid space. On day 7 angiography was repeated, and the animals were killed under anesthesia for necropsy. One of the animals in the placebo group developed a cerebral infarction on day 5. In the placebo group significant vasospasm occurred in all major right and left‐sided anterior cerebral vessels (P< 0.01). No vasospasm occurred in the rt‐PA‐treated animals. Whereas gross subarachnoid clot was found in all animals in the placebo group (mean clot weight 1.13 g), only a small fragment of clot was found in a single rt‐PA‐treated animal. The gel had no adverse microscopic effects on the brain. Intrathecal thrombolysis with rt‐PA is safe and effective in preventing vasospasm in primates. (Neurosurgery24:491‐498, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;In 102 cases of ruptured intracranial aneurysms, the cervical as well as the cranial areas were explored by angiography. Loops in the course of the cervical vessels were present in 28 patients; features of fibromuscular dysplasia were present in 31 patients; and in 50 patients, no abnormalities were observed. In 7 patients, both cervical anomalies were present. Loops were associated with single aneurysms (95%), located primarily on the anterior communicating artery (76%), predominantly in men (M/F = 1.6). Aneurysms with fibromuscular dysplasia affected women more than men (F/M = 7), were frequently multiple (58%), and were located mainly on the intracranial part of the internal carotid and vertebral arteries (51%). These data suggest new concepts of aneurysm formation from inherited diseases and should permit the detection of some aneurysms before rupture. (Neurosurgery24:499‐508, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;Cerebral blood flow velocities in the middle cerebral arteries were measured using transcranial Doppler in 12 patients with conditions that ultimately resulted in brain death. All patients had sustained closed head injury, gunshot wounds to the head, or spontaneous intracerebral hemorrhages. When clinical criteria for brain death were met, a characteristic pattern was found with transcranial Doppler. This pattern consisted of reverberating flow, with forward flow in systole and retrograde flow in diastole. When this pattern was seen, there was arrest of cerebral flow, as measured by radionuclide scanning using technetium, in all patients studied. Transcranial Doppler is a useful technique for easily assessing the arrest of the cerebral circulation. (Neurosurgery24:509‐513, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;Ten unfixed human brains were examined under an operating microscope to evaluate the feasibility of reimplanting the parasagittal veins into the superior sagittal sinus. On average, there were 6.5 veins draining the surface of each hemisphere in the anterior frontal region, 3 veins draining each posterior frontal region, 4 veins draining each parietal region, and 1 vein draining each occipital region. The veins were most frequently 0.1 to 1.0 mm in diameter, but were as large as 3.0 mm in the anterior frontal and occipital regions, 3.5 mm in the parietal region, and 5.0 mm in the posterior frontal region. The mean vein length between the superior sagittal sinus and the first lateral attachment was 3.0 to 7.4 mm; individual veins were as long as 30.0 mm. The 20 hemispheres contained a total of 5 veins in the anterior frontal region. 7 veins in the posterior frontal region, and 8 veins in the parietal region that appeared to have an adequate diameter and length for microsurgical reimplantation into the superior sagittal sinus. The superior sagittal sinus had a mean width of 4.3 mm and depth of 3.6 mm in the midanterior frontal region and enlarged to a mean width of 9.9 mm and depth of 6.8 mm in the midoccipital region. In all sites, the sinus appeared to be structurally compatible with vein reimplantation. In 3 cases, veins 2.8 to 4.6 mm in diameter were reimplanted microsurgically into the sinus; in each case, the anastomosis was technically satisfactory and patent. These results support the feasibility of reimplanting parasaggital veins into the superior sagittal sinus for such problems as trauma, tumors, and cortical venous thrombosis. Veins suitable for reimplantation are located primarily in the posterior frontal and parietal regions. (Neurosurgery24:514‐520, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;In order to investigate the clinical significance of redundant nerve roots of the cauda equina (RNR) and their pathogenesis, the following studies were performed: 1) examination of 1,256 myleograms of patients with lumbar disease; 2) clinical analysis of 55 patients with RNR and 75 without RNR; 3) electrophysiological examination of 9 patients with RNR; and 4) anatomical and histopathological examination of 6 autopsy cases. RNR were found in 42% of patients with severely constricted spinal canals. In comparing patients with RNR and those without RNR, RNR were found in older patients, these patients exhibited a longer period from the onset of the symptoms to the time of myelographic manifestation, and they caused more severe signs and symptoms. The spatial distribution of redundant nerve roots and the extent of degeneration of nerve fibers in redundant nerve roots indicated the close causal relationship between RNR and constriction of the spinal canal. As the pathogenesis of RNR, the authors suggest a squeezing force from the constricted spinal canal acting on the nerve roots. (Neurosurgery24:521‐528, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;After determining that 15 patients with high spinal cord injuries who were permanently apneic had viable phrenic nerves, electrophrenic respiration units were implanted. Thirteen of the patients (86%) achieved full‐time respiration and two more achieved half‐time respiration. Despite the loss of 8 patients to unrelated problems, 7 now use electrophrenic respiration continuously, one having done so for 16 years. The patient selection criteria, neurophysiological evaluation method, surgical procedure, postoperative care, and methods for diagnosis of system failures are presented. A comparison of the cervical and thoracic procedures is made. The cervical approach is preferred. Complications consisted primarily of equipment failures. For the external components there were several cases of antenna connection and battery connection failures. The implanted receivers failed in 6 cases with an average lifetime of 48 months, ranging from 24 to 108 months. In one case fibrosis around the electrode resulted in failure to stimulate the phrenic nerve effectively. In another case, infection required removal of the system which was reimplanted later and has continued to provide successful ventilation. (Neurosurgery24:529‐535, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;The cases of 13 infants (median age, 3 months) who sustained nonaccidental trauma were reviewed. All presented with profound neurological impairment, seizures, retinal hemorrhages, and intracranial subarachnoid and/or subdural hemorrhages. Of 8 infants who died, autopsy was performed on 6. No patient had a skull fracture, and only one had an extracalvarial contusion. Five of the 6 patients on whom autopsy was performed had injuries at the cervicomedullary junction consisting of sub‐ or epidural hematomas of the cervical spinal cord with proximal spinal cord contusions. The authors conclude that direct cranial trauma is not an essential element of the injury mechanism in young patients who sustain severe whiplash‐shake injuries. In addition to the classic injuries reported to occur with the shaken‐baby syndrome, hemorrhages and contusions of the high cervical spinal cord may contribute to morbidity and mortality. (Neurosurgery24:536‐540, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;Fresh xenografted human malignant astrocytoma cells migrate throughout the host rat brain. Cells from three Grade 3 human malignant astrocytomas were prelabeled withPhaseolus vulgarisleucoagglutinin (PHAL) and then xenografted into implantation pockets in rat host cerebral cortex. The human malignant astrocytoma cells in the host brain were immunocytochemically double‐labeled for the presence of PHAL, which is used as a marker for graft derived cells, and either glial fibrillary acidic protein (GFAP), a specific marker for astrocytes and astrocytoma cells, or apolipoprotein E (APOE) 7 days, 14 days, 21 days, and 1 month later. Fresh human malignant astrocytoma cells (Grade 3 and 4) contained APOE and GFAP. The xenografted cells preserved APOE and GFAP in the host. PHAL double‐labeled human malignant astrocytoma cells were found on the glia limitans along the entire circumference of the brain, in the corpus callosum, internal capsule, entopeduncular nucleus, optic tract, and median eminence. In addition, astrocytoma cells were observed in the cingulum, habenula, arcuate, and supraoptic nucleus. Astrocytoma cells entered the space of Virchow‐Robin, migrated along parenchymal blood vessels and between the ependymal and subependymal layers of the third and lateral ventricles. APOE was a consistent marker for the migrating human malignant astrocytoma cells, but not an exclusive marker of the xenografted cells, since host rat reactive astrocytes also expressed APOE. (Neurosurgery24:541‐546, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

&NA;Photodynamic therapy is under intense investigation as an adjuvant treatment for malignant glial tumors of the central nervous system. Photofrin‐II (HpD‐II) is currently the most actively investigated photosensitizing agent. A crucial issue regarding the safe and efficacious usage of HpD‐II‐based photodynamic therapy is the individual in vivo kinetics of tumor uptake and retention, compared with normal brain clearance. The optimal time for photoactivation of sensitized tumor must be known to ensure a high target‐to‐nontarget ratio, resulting in the maximal tumor destruction while preserving normal brain. Our laboratory developed a radionuclide scan based on111indium (111In)‐labeled HpD‐II to evaluate HpD‐II localization and clearance noninvasively within a canine model of intracerebral gliosarcoma. Synthesis of the111In‐HpD‐II complex in >90% yield is achieved by a simple, rapid labeling method. Radiochemical purity and stability were verified by high‐performance liquid chromatography. Using the canine model of intracerebral gliosarcoma, we followed the uptake of111In‐HpD‐II in tumors with serial scintillation scanning. Localization of the tumor by111In‐HpD‐II has been verified by contrast‐enhanced computed tomographic scan followed by gross and histological examination of the enhancing brain region. Total body biodistribution of111In‐HpD‐II at various times after injection has been evaluated. The ratio of uptake in tumor compared with surrounding brain peaked at 72 hours after injection. The knowledge of regional distribution and concentration of a photosensitizing agent within a tumor mass and surrounding brain allows for the most efficacious timing and localization of a photoactivating source. (Neurosurgery24:547‐556, 1989)

ISSN:0148-396X    

出版商:OVID    

年代:1989

数据来源: OVID