Experimental Study of Initiation of Cortical Spreading Depression by Excitatory Amino Acids Using a New Topical Application Model

The purpose of this study was, first, to devise a new model for topical application of excitatory amino acids(EAAs) to rat cerebral cortex that successfully and repeatdly initiate the cortical spreading depression(CSD). Then, by using this model, six major EAAs that are known to act on single or multiple subtypes of EAA receptor were examined; glutamate, kainate, aspartate, N-methyl-D-aspartate(NMDA), quisqualate, and alpha-amino-3-hydroxy-5-methyl-4-isoxazoie-proprite(AMPA). Through the model, with a cone-shaped well buried in 1.5mm depth of the cerebral cortex, these chemical agents were topically applied to the cortical gray matter. A total of 50 Sprague-Dawley rats were used and divided into seven groups including the sham group. Doses of each EAA between 10(-7) and 10(-4)M concentrations were escalated for triggering the CSD and its rate of consistency in triggering was also evaluated. In the overall results. CSDs were repeatedly initiated in all experimental groups with relatively consistent rates. Duration of CSDs were 1-4 minutes(mean 2.2+/-1.4) and amplitudes were 20-40mV. Effective dose(50)(ED(50)), that trigger over 50% of CSD was 10(-5)M(n=8) for glutamate, 10(-7)M(n=8) for aspartate, 10(-5)M(n=7) for AMPA, 10(-5)M(n=7) for quisqualate, and 10(-4)M(n=7) for NMDA and kainate group. Among those acting on the single receptor, AMPA was shown to be the most effective in triggering CSD, and NMDA, and kainate were in descending orders. Aspartate that was known to act on multiple EAA receptors, showed the highest rate of triggering CSD among all groups, but glutamate, known to act on all receptors of its subtypes, showed the most consistent rate of triggering CSD at dose escalation. These results revealed that those EAA acting on multiple receptors, namely aspartate and glutamate, showed the highest and most consistent rate of triggering CSD. Among those acting on single channel of receptors. AMPA was the most effective, although its consistency and rate of triggering of CSD was somewhat lower than.

Analysis of Morphometric Characteristics of Lumbar adieles

During the past decade, internal fixation techniques for stabilization of spinal fracture, correction of spinal deformity and immobilization in degenerative spinal diseases have increased in general, pedicle screw fixation of the spine provides the three dimensionally rigid grip on each vertebra and minimizes the levels of spinal segment that is needed for proper fixation. But with the increasing use of pedicle screw, there is an increase in incidences of complication. Major complications of pedicle instrumentation are screw malposition, pedicle fracture, iatrogenic foraminal encroachment, injury to the facet joints or vessels, and mechanical failure. These complications may be associated with irreversible damage of both vertebral and neural elements. Therefore, full understanding and knowledge of vertebral morphology is essential for proper instrument fixation and avoidance of complications. A total of 500 pedicle measurements were made from L1 to L5 vertebra. Five morphometric parameters were studied, transverse pedicle width, transverse pedicle angle, depth to anterior cortex, sagittal pedicle width, sagittal pedicle angle. Measurements were done using both spinal computed tomography and simple lumbar X-rays. As for the results, the means of transverse pedicle width is 7.9-16.6mm, transverse pedicle angle is 8.3-29.1 degrees And depth to anterior cortex is 43.8-47.9mm. The results were compared with previous data.

Thoracic Myelopathy Caused by Multiple Ossified Ligamentum flavum Combined with Ossification of the Posterior Longitudinal Ligament

The authors report a case of thoracic myelopathy caused by multiple ossification of the ligamentum flavum(OLF) combined with ossification of the posterior longitudinal ligament(OPLL). A 52-year-old man had progressive motor weakness and numbness in the lower extremities. Diagnosis was made from the MR imaging that provided useful information about the multiple lesions in the lower cervical and upper thoracic area and about the degree of spinal cord compression. The surgical approach consisted of two stages: Posterior decompression for OLF(first stage) and anterior decompression for OPLL, followed by interbody fusion(second stage). The patient had satisfactory improvement after surgical intervention.

Leukoencephalopathy Associated with 5-Fluorouraeil and Cisplatin Therapy

Increasing vigorous chemotherapy for cancers including primary and matastatic tumors has resulted in prolonged survival. However, there has been an associated increase in neurotoxicity as a result of it. All classes of chemotherapeutic agents contain drugs that are potentially neurotoxic. The authors has studied three cases of leukoencephalopthies developed during adjunctive therapy with 5-flurouracil and cisplatin for adenocarcinoma of the stomach. None of the patients had evidence of metastasis or any previous neurologic diseases. The duration of chemotherapy before onset of neurological symptoms ranged from 8 to 12 weeks. Two of the 3 patients presented progressive decline in mental status and ataxia after 2~3 weeks, while the third one had two unexplained episodes of loss of consciousness. In all of these patients, magnetic resonance imagings demonstrated prominent periventricular white matter lesions. Cerebral biopsies were performed stereotaxically in 2 patients. The morphological features were active demyelinating disease and edema. All three patients had improved after the cessation of chemotherapy and a short course of corticosteroid therapy, suggesting that these alarming events such as nausea, vomiting dizziness, dysarthria, and mental change were a toxic reversible side effects from these chemotherapeutic agents. This syndrome may represent the pathological basis for 5-fluorouracil neurotoxicity, however we cannot completely exclude the role of cisplatin in the occurences of the above syndromes.

Statistical Analysis of 631 Cases of Surgically Treated Brain Tumors in Korea University Hospital

The authors present a statistical survey of the general incidence, age distribution, and preferential site of 631 tumors of the brain which have been surgically treated at Korea university medical center, department of neurosurgery over the last period of 10 years from 1985 to 1994. Among them 269 cases were males and 362 were females. Of the 631 intracranial neoplasms verified histologically, tumors of neuroepithelial tissue comprised 34%(212 cases), tumors of meninges 23%(148 cases), pituitary adenoma 18%(114 cases), metastatic tumors 8%(50 cases), neurilemmomas 8%(49 cases), germ cell tumors 3%(13 cases), cyst and tumor like lesions 3%(16 cases), and lymphomas 1%(5 cases). Of the 178 gliomas, astrocytic tumors comprised 83%(148 cases), oligodendroglial tumors 11%(20 cases), ependymal tumors 3%(6 cases) and mixed gliomas 1.7%(3 cases). Brain tumors occurred most frequently in the age group of 45-50 years, as seen by an incidence of 63 cases(10%). The male to female ratio was 0.74: 1. Tumors that showed a definitive preponderance of females over males were meningiomas, neurilemmomas, and pituitary adenomas. Supratentoral and infratenorial cases were 73%(461 cases) and 26%(162 cases), respectively and the remaining cases involved both sites. Of the 114 cases of childhood and adolescent tumors, 60 were male and 54 were female. Supratentorial tumors were 56% and infratentorial were 44%. The tumors in order of frequency were astrocytomas(28%), primitive neuroectodermal tumors(21%), craniopharyngioma(10%) and so on. Meningiomas occurred most frequently in parasagittal/falx area(25%), followed by cerebral convexity 23%, sphenoid 14%, posterior fossa 13%. Among pituitary adenomas, prolactinomas(32%) were the most common and followed by null cell adenomas 31%, growth hormone cell adenomas 15%, mixed GH-PRL cell adenomas 11%.

Acquired Chiari-malformation after Ventriculoperitoneal Shunt for Hydrocepalus Associated with Neurocysticercosis

Acquired Chiari malformation is a term describing the low lying cerebellar tonsils subsequent to the documentation of a normal hind brain. It is radiograpnhically indistinguishable from Chiari-I type malformation. Ventricular and lumbar shunting are known predisposing factors in patients who develop such tonsilar descent. Managements of acquired Chiari malformations include ventriculoperitoneal(V-P) shunt. Ventriculoatrial(V-A) shunt or posterior fossa decompression after removal of lumboperitoneal(L-P) shunt. The authors recently have encountered a patient who developed an acquired chiari malformations after V-P shunt for hydrocephalus associatd with neurocysticercosis. This case of chiari malformation is presented as our report, together with pertinent literature review.

Biomechanics of Cervical Spine

A through understanding of the biomechanics of the cervical spine is necessary to apply its knowledge to management of cervical disorders intelligently. In this article authors tried to fully review the biomechnics of cervical spine by, first, going over the basic anatomical and physiological characteristics of the cervical spine. Then, with these in mind, related kinemtics are reviewed with discussion of some of important clinical applications related to these facts. Finally, diagnostic points of cervical instability are stressed which can be used some of the guidelines in management of such patients in actual clinical situations.