Genetic information is stored in all cells as genomic DNA. Differences among cells of a single organism reflect differences in gene expression. Gene expression is controlled mainly at transcriptional step. Once RNA transcripts are synthesized, they are spliced to become mature mRNA, which are transported from the nucleus to the cytoplasm and used as templates for protein synthesis. Each step is regulated so as to accommodate to the needs of each cell. Gene expression can be greatly altered by environmental stimuli, which are transferred by istracellular signal transduction systems. Gene expression is also regulated during various disease processes. Neoplastic transformation is believed to originate via mutation and anomalous gene expression. Protooncogenes, which are responsible for transformation and progression of neoplasms, are involved in the signal transudation system to the level of gene expression. Brain tumor research, therefore, is closely linked to the study of altered gene expression. The process of cell death in brain tumors is, at least in part, regulated via changes in gene expression. The process of such active suicidal cell death is known as apoptosis. In acute neurosurgical disorders such as head trauma and cerebrovascular diseases, the central nervous system (CNS) is damaged so quickly that there seems to be no possibility of involvement of gene expression. However, a secondary process, which could exacerbate a patient's condition, takes place following the initial injury. In this secondary process, cells in the CNS seem to alter their gene expression in order to survive. One such cellular reaction is the stress response. Expression of genes encoding various growth factors is also important for the survival of CNS cells under disease.

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All living organisms, from bacteria to higher eukaryotes, share a common response against enviornmental conditions unfavorable to their survival. This response is called the heat shock or stress response, and results in the synthesis of a set of proteins termed the heat shock or stress proteins. These proteins also play an essential role as molecular chaperones under normal and/or stressful conditions. In the higher eukaryotes, the heat shock or stress response is mainly regulated at the transcriptional level by the activation of a pre-existing transcription factor, the heat shock factor. Although there has been increasing research interest in the heat shock/stress gene expression in the nervous system under stressful conditions, the molecular mechanisms regulating the heat shock or stress response in the CNS remain unknown. Recent studies also suggest that the same regulatory pathway for heat shock gene transcription that exists in single cells after heat shock also exists in whole animals affected by some pathologic condition. These topics and the cellular signals for heat shock gene transcription under in vivo pathologic conditions are discussed in this paper.

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Apoptosis has recently been proved to be involved in pathogenesis of various kinds of diseases such as some cancers, autoimmune diseases, neurodegenerative diseases, myelodysplastic syndromes, and ischemic injury as the molecular mechanism of apoptosis has been elucidated rapidly and progressively. In this review, the historical background and the molecular mechanism of apoptosis known so far was summarized from the literature. Also, the biological significance of apoptosis and a therapeutic strategy against diseases in which apoptosis is involved in the field of neurosurgery is discussed.

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Recently, molecular genetic analyses have revealed that the genesis and progression of tumors are the results of accumulated changes in two major classes of growth-regulatory genes : the oncogenes and the tumor-suppres-sor genes. Most of these genes belong to an intra-cellular signal transduction pathway or to cell-cycle regulators. Several sequential genetic alterations, i. e., the hyperactivation of growth promoting genes and the inactivation of growth-inhibiting genes, appear to be required to direct cells toward the malignant phenotype. In this regard, the genomic instability that is induced by the mutations of genes important for cell-cycle regulation and DNA repair, such as the p53 and pl6 genes, leads to the next multiple gene alterations. Gene amplification, point mutation, insertion, translocation, and rearrangement are the major mechanisms of oncogene activation. In brain tumors, alterations of the erbB-1 gene encoding EGF receptor have been frequently reported. Other oncogene amplifications such as sis, c-myc, and PDGF-R have also been reported. Further, inactivation of many tumor-suppressor genes, includlng the p53, NF1, NF2, and the pl6 genes, and the VHL gene in cases of the von Hippel Lindau disease, have been proved in brain tumors. In this paper, the functional role of some tumor-suppressor genes is discussed. Basic ongoing research of these oncogenes and tumor-suppressor genes may soon contribute to a breakthrough and the development of new technological methods for brain tumor treatment.

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Various neurotrophic factors are essential for the survival, sprouting, and regeneration of neurons, and factors that have been identified comprise two major groups : these belonging to the fibroblast growth factor (FGF) family or the neurotrophin group. This review deals with structure, function, and modification of the gene expression in the FGF family and their receptors. The basic FGF protects against a neuronal ischemic injury. After an ischemic injury, Its receptor is upregulat-ed within a day whereas the FGF protein expression is delayed for another 2 days, which may explain why exogenously administered FGF has been found effective for a neuronal ischemic injury. If FGF is topically applied immediately after such an injury it upregulates and prolongs the neuronal fos gene expression. It has been found that applied FGF is able to extend the fos expression for up to 24 hours after a cortical ablation, so that fos-positive cells in the neuron were also found in the glia, suggesting that FGF modulated this neuronal-glial interaction. The group of neurotrophins consists of the nerve growth factor (NGF), the brain-derived growth factor (BDNF) , and neurotrophin-3 (NT-3) . Their gene expression can also be modified by ischemia, which upregulates BDNF and NGF but downregulates NT-3. The neurotrophin receptors are composed of heterodimers of the trkA, trkB, and trkC genes and a low-affinity NGF receptor. Under conditions of ischemia, trkB and trkC are upregulat-ed. The growth inhibitory factor (GIF) can also affect neurons because it suppresses neurite outgrowth. After an ischemic brain injury, the GIF gene expression is immediately suppressed, but 4 days later it upregulates transient-ly, thereby suggesting a termination of regenerative sprouting. Thus, the gene expression of these growth factors and their receptors are finely controlled and the maintenance of these interacting mechanisms is necessary for an effective recovery from such injuries.

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Zonisamide (ZNA) suppositories, which were prepared in our hospital, were given prophylactically to 10 patients. ZNA suppositories of 2OO mg or 400 mg were administrated to 5 patlents each, once a day for consecutive 3 days, and the plasma ZNA concentrations after rectal administration were measured. Although the plasma ZNA concentration after rectal administration was initially lower than that of oral administration, the two concentra-tions were the close after 24 hours. Two patients with status epilepticus who were treated with ZNA suppositories showed clinical improvement and satisfactory plasma concentrations of the drug at the saturated state. ZNA suppositories were thought to be beneficial for neurological patients in whom antiepileptic drugs cannot be administrated per os.

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The outcome of a severe head injury is usually unfavorable. Using the new computed tomographic (CT) criteria and their subsequent modifications of the Traumatic Coma Data Bank, severe head injuries have been classified into 2 groups : a diffuse brain injury (DBI), categorized in order of severity into 4 gradings : DBI I to IV, or a mass lesion, categorized into 3 types : an epidural hematoma (EDH), an acute subdural hematoma (ASDH) , or an intracerebral hematoma (ICH) . This study was undertaken to elucidate the prognostic factors of severe head injuries. Two hundred and thirty-one patients with a Glasgow Coma Scale (GCS) score of 8 or less were analyzed. The patients manifesting a severe systemic injury (systolic blood pressure<9O mmHg on admission) were excluded. Apart from the severe head injury, other clinical factors affecting the prognosis were also analyzed, i. e., the patient's age, the GCS, pupillary abnormalities (bilateral dilated unreactive pupils), an impaired oculocephalic response, subarachnoid hemorrhage and, if a lesion was involved, the CT findings of the lesion and the possible presence of other lesions. Each outcome was evaluated at 6 months after treatment by using the Glasgow Outcome Scale, in which a good outcome is defined as a good recovery or a moderate disability and a poor outcome is considered to be a severe disability, a vegetative state, or death. The Chi-square test and logistic regression analysis were used for the statistical evaluations. Results : A11 the DBI I cases had a good recovery. As for the DBI II cases, patients with CT-detected multiple lesions had significantly poorer outcomes than patients with a single lesion (p<0.001) . The patient's age (p>0.0510) and the presence of multiple lesions (p>0.0505) were powerful factors that affected the prognosis in this group. As for the DBI III and DBI IV patients, those with a GCS score of from 3 to 5 had significantly poorer outcomes than these with a score of from 6 to 8 (p<0.001) . The only significant prognostic factor was the GCS score in these 2 groups (p=0.0001) . As for EDH and ASDH patients, those with a GCS score of from 3 to 5 had significantly poorer Outcomes (p<0.01 and p<0.05, respectively) . The GCS score was the sole significant outcome factor in both groups. Finally, of a total of 14 ICH patients, 12 (860%) had unfavorable outcomes. These results indicate that, with the exception of DBI II cases, the GCS score is the only clinical valuable factor for an early prediction of a ontcome in severe head injury.

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We report the case of a 76-year-old female with an arachnoid cyst of the left frontal convexity who was admitted to hospital because of a one-month history of progressive dementia. Results of a computerized tomographic (CT) scan and magnetic resonance imaging (MRI) revealed that an arachnoid cyst of the left frontal convexity was compressing the left frontal lobe. Thus, a left frontoparietal craniotomy was performed and the outer membrane was totally resected. Following this surgery, the dementia completely disappeared. Five years after this operation, memory disturbance recurred. A CT scan and MRI showed the recurrence of this arachnoid cyst and cyst-peritoneal shunt surgery was provided. Follow-up CTs disclosed the disappearance of the arachnoid cyst and her memory improved postoperatively. Primary arachnoid cysts are usually discovered at an early age and rarely are they encountered in the elderly. Arachnoid cysts expand slowly and because of brain compression and/or obstruction of the CSF flow, they induce symptoms such as body developmental delay, headaches and/or seizures. However, a few reports have indicated that an arachnoid cyst can also cause dementia. We discuss the surgical treatment of this case in which it was decided that the resection of the cyst wall would be the first treatment of choice. On the recurrence of this cyst, the cyst-peritoneal shunt proved very effective. Although senile dementia carries a poor prognosis, some types of dementias are surgically curable.

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Meningioangiomatosis (MA) is a rare malformation of the central nervous system. It has not been previously described in the literature. We report here the first case of MA involving the sylvian fissure in a 10-year-old boy. Clinicaly, he presented with a syncopal episode. Computed tomography revealed an enhancing hyperdense lesion in the right sylvian fissure. This was confirmed by magnetic resonance imaging of the brain with the lesion being isointense on T1-weighted images and hypointense on T2-weighted images and intense enhancement with gadolinium. The lesion was surgically removed and on histopathologic examination, the spindle cells were positive for vimentin on immunostaining. We suspect that it was not derived from arachnoid cap cells but originated from the mesenchmal cells. We summarize here the reported cases of MA and discuss the pathogenesis of this condition.

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We discuss the case of a 16-year-old boy who presented visual disturbances caused by a papilledema. At the age of 5 months he had undergone a V-P (ventriculo-peritoneal) shunt placement and when 1 and 6 years old he had recieved a total of 3 shunt revisions. Previously, he had experienced nausea and headaches but these conditions then improved over the course of several weeks. When he first came to our outpatient department, he had no clinical symptoms and CT scans showed no dilatation of the ventricles. However, three weeks later an ophthalmoscopic examination led to the detection of a remarkable papilledema, although CT scans still showed no enlargement of the ventricular size. After a shunt revision, his visual disturbances and the papilledema lessened even though CT scans still showed no change in the ventricular size. Based on the results of this case, we emphasize the importance of the optic fundi findings, regardless of the absence of typical clinical symptoms and CT scans that show no ventriculomegaly, especially in patients who have undergone a shunt procedure in infancy and have a history of repeated revisions.

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We have evaluated the efficacy of intraoperative thrombolysis by using a recombinant tissue plasminogen activator (t-PA) and irrigation for treating ruptured cerebral aneurysms. We have tested two doses of t-PA in this method of treatment in 37 Patients with a ruptured cerebral aneurysms. For controls, 16 other patients with a ruptured aneurysm only received irrigation of the cisterns. A11 53 patients had Fisher group 3 hemorrhage of the cisterns, and had undergone surgery within 5 days of their last rupture, with most of these patients having received surgery within 3 days. Results revealed that 12 patients who received a t-PA dosage of 12x10^6 U showed a statistically significant reduction in the incidence of permanent delayed ischemic deficits (DID). In contrast, 25 patients treated with a t-PA dosage of 6x10^6 U and the control patients given irrigation alone had a similar DID incidence. However, there was no statistically significant differences among the 3 groups with regard to the Glasgow Outcome Scale score at three months after the clinical onset, the CT scan size of the cerebral infarction, or the incidence of hydrocephalus.

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We report 2 cases involving the resection of the sigmoid sinus due to a large petroclival meningioma in which the intrasinal pressure of the sigmoid sinus was monitored during the course of the operation. In both cases the intrasinal pressure did not markedly increase after clamping of the sigmoid sinus. However, the intrasinal pressure did increase in one case due to an increase in the intratracheal pressure but did not increase in the other case. In the case that showed no increase in the intrasinal pressure, a trans-sigmoid approach had been used for the operation. Further, no complications occurred in this case after the resection of the sigmoid sinus. This finding suggests that there may be various routings that enable venous drainage to occur during surgery, even in cases that do not show a remarkable increase in the intrasinal pressure after clamping of the sigmoid sinus.

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