Electro-optic guided-to-radiation mode conversion in annealed proton-exchanged PPLN waveguides

We report the design and experimental demonstration of electro-optically active TM-guided to TE-radiation mode converters in annealed proton-exchanged (APE) periodically poled lithium niobate (PPLN) channel waveguides in telecom S-C-L bands (1495-1640 nm). A maximum mode conversion efficiency of >95%/cm was obtained at 1520 nm from a 24-μm-period APE PPLN waveguide under an electro-optic (EO) field of ~6.3 V/μm at 35°C. This efficiency has been enhanced by a factor of >4.6 over a waveguide built in the single-domain (unpoled) LiNbO3; it is also to the best of our knowledge the most efficient guided-to-radiation (GTR) mode converter ever reported based on LiNbO3 on-axis waveguides. A conversion bandwidth of ~250 nm was also observed from this EO GTR mode converter.

Interrelationship between exposure to PCDD/Fs and hypertension in metabolic syndrome in Taiwanese living near a highly contaminated area

Metabolic syndrome (MetS) consists of a constellation of metabolic abnormalities that confer increased risk of cardiovascular disease. There is a positive correlation between exposure to persistent organic pollutants and MetS. We examine the association between PCDD/Fs and MetS components in 1490 non-diabetic persons living near a highly dioxin-contaminated area. We used factor analysis, with a set of core variables considered central features of MetS and PCDD/Fs, to group similar risk factors. Serum PCDD/Fs were positively and significantly correlated with the number of MetS components. Four risk factors-lipidemia, blood pressure, body size, and glycemia-accounted for 72.6% of the variance in the 10 core factors, and PCDD/Fs were linked to MetS through shared correlations with high blood pressure. After adjusting for confounding factors, we found that diastolic blood pressure (β=0.018; p=0.006), glucose (β=0.013; p=0.046), and waist circumference (β=0.721; p=0.042) significantly increased with increasing serum PCDD/F levels. We found significant trends for associations between metabolic syndrome and serum low-chlorinated PCDD/Fs. The highest quintiles of 2,3,4,7,8-PeCDF, 1,2,3,6,7,8-HxCDF and 2,3,7,8-TCDD had the top three adjusted ORs (95% CI) of 3.5 (1.9-6.3), 2.9 (1.7-4.9) and 2.8 (1.6-4.9), respectively. We also found a slight monotonic relationship between serum PCDD/Fs and the prevalence of MetS, especially when the serum dioxin level was higher than 25.4pg WHO(98)-TEQ(DF)g(-1) lipid (the fourth Quintile). We hypothesize that high-dose exposure to PCDD/Fs is a blood pressure-related factor that raises MetS risk.

Molecular characterization of mungbean (Vigna radiata L.) starch branching enzyme I

Mungbean (Vigna radiata L. cv. Tainan no. 5) starch branching enzyme I (SBE, EC 2.4.1.18) cDNA, VrsbeI, was cloned, and its expression was characterized. Conserved regions of the family B SBE were used to amplify a full length cDNA of 2208 bp. Phylogeny was analyzed, and the partial 3D structure and functional features were predicted. Catalytic residues were identified in the (α/β)(8)-fold, and a unique loop from F365 to F376 between β3/α3 was located. Gene expression of VrsbeI in seeds during growth showed that the transcript appeared from week 1 and increased substantially at week 3-4. It was cloned into the pET30 vector and expressed in E. coli BL21(DE3) pLysS cells as a soluble recombinant protein. The affinity-purified recombinant VrSBEI exhibited a specific activity of 314.6 U/mg as an active enzyme with 114-fold activity enrichment from the crude extract.

Pulsed orange generation optimized in a diode-pumped Nd:YVO4 laser using monolithic dual PPLN electro-optic Q switches

We report a pulsed intracavity sum-frequency generator in a diode-pumped, dual-wavelength Nd:YVO(4) laser whose operation was optimized with two electro-optic Q switches built in a monolithic periodically poled lithium niobate (PPLN) crystal. The dual PPLN Q switches, though integrated, are able to work separately at their respective working wavelengths of 1064 and 1342 nm. At 4.8 W diode pump power and 5 kHz Q-switching rate, a maximum orange (593 nm) output peak power of >480 W was achieved in this laser system using the Q-switch opening-time offset technique. This power is approximately 1.7 times higher than that obtained with the system operated in a conventional single-Q-switch mode.

Effect of citral, eugenol, nerolidol and alpha-terpineol on the ultrastructural changes of Trichophyton mentagrophytes

The antifungal effects of citral, eugenol, nerolidol and alpha-terpineol on Trichophyton mentagrophytes were investigated. Citral over 0.1 mg/ml strongly inhibited the hyphal growth of T. mentagrophytes, and the antifungal activity of alpha-terpineol was less effective. The morphological changes of the fungus exposed to the terpenes were observed by electron microscopy. The hyphae were distorted and collapsed at 0.2, 0.4 and 1 mg/ml of eugenol, nerolidol and alpha-terpineol respectively, and cell membrane and organelles were irreversibly damaged at 0.2 mg/ml citral. These suggested that four terpenes possess antifungal activity against T. mentagrophytes, and the activity might lead to irreversible cellular disruption.

Gamma knife radiosurgery for medically refractory idiopathic trigeminal neuralgia

Gamma knife radiosurgery (GKS) has been generally considered as a viable therapeutic option for the management of medically refractory idiopathic trigeminal neuralgia (TN). We reviewed our experience with GKS in patients with TN. Between Feb 1996 and May 2006, 77 patients with medical refractory idiopathic TN were treated using GKS. Thirty-six patients who had undergone other previous procedures, previous GKS, or had brain stem lesion, atypical symptoms, were excluded from this study. Pain improvement was achieved in 38 of the patients with TN (pain response rate 92.7%). Twenty-three patients were pain free and 15 had reduced pain. There were no serious complications. We think that GKS is an effective treatment option for patients with medical refractory idiopathic TN.

Current status and issues in cancer stem cell study

Cancer stem cells (CSCs) have been positively identified and successfully isolated from some but not all cancers. The studies on CSCs to date suggest that these cells are rare among the tumor cell population, and they are capable of self-renewing and maintaining tumor growth and heterogeneity. Therapies aimed at CSCs have shown some promise, but their further development will require a more thorough understanding of the biology of CSCs and methods for identifying and isolating this cell subpopulation. This review examines what is known to date regarding the similarities and differences between cancer and somatic stem cells: CSC surface marker development and cell isolation (including a model isolation from our lab), the frequency, potential origin, and signal transduction of CSCs, and the current state of CSC-targeting therapeutic strategies.

Bladder cancer initiating cells (BCICs) are among EMA-CD44v6+ subset: novel methods for isolating undetermined cancer stem (initiating) cells

Bladder cancer stem (initiating) cell has not been isolated now, and no one verified its persistence experimentally. The aim of this study was to conclude the persistence of bladder cancer stem (initiating) cell in human primary bladder cancer and investigate the possibility of EMA(-) CD44v6(+) as markers of bladder cancer stem (initiating) cell. Genes differentially expressed between normal urothelium and low malignant bladder cancer were identified by DNA array assay. Overpressed stem cell related genes, Bmi-1 and EZH2, were verified by immunohistochemistry. Side population cells in bladder cancer were found under fluorescence microscope. The value of 28 potential surface markers of bladder cancer stem (initiating) cell for isolating them were judged by immunohistochemistry. Both EMA(-) and CD44v6(+) cells located in basal layer (potential location of stem cells). After gathering the CD44v6(+) cells and EMA(-) cells by magnetic cell sorting, their ability for colony-forming, self-renewal and extensive proliferation were assayed by cells culture. Both EMA(-) cells and CD44v6(+) cells posses the ability for colony-forming, self-renewal and proliferation. We conclude the persistence of bladder cancer stem (initiating) cell. Bladder cancer stem (initiating) cell might be among EMA(-) CD44v6(+) subset. Our strategies for isolating bladder cancer stem (initiating) cell might be useful for isolating other undetermined epithelial cancer stem cell, especially those in well-differentiated cancers.

AAV-GAD gene for rat models of neuropathic pain and Parkinson's disease

The introduction of therapeutic genes to neurons by genetic modification has potential as an effective treatment for CNS disorders for all that a successful clinical application has not yet been fully implemented. In this paper, we will discussed the role of AAV vectors with the GAD65 gene for animal models of PD and neuropathic pain. AAV vector is one of the most attractive gene delivery vehicles for direct introduction of therapeutic genes into the CNS in the treatment of neurological diseases. GAD65 is present as a membrane-associated form in synapses and is primarily involved in producing synaptic gamma-aminobutyric acid (GABA) for vesicular release. We constructed rAAV-GAD65 expressing rat GAD65 and demonstrated that rat Parkinsonian symptoms can be significantly improved concomitantly with the production of GAD65. We also demonstrated rAAV-GAD65 as a successful gene delivery vehicle in a chronic pain model by administrating rAAV-GAD65 to DRGs because GABA driven by GAD is a major inhibitory neurotransmitter in the dorsal horn of the spinal cord and also plays an important role in the ventral horn. We believe that AAV vectors can be excellent candidates for gene therapy of neurological diseases.

Dopamine transporter density in the basal ganglia in obsessive-compulsive disorder, measured with [123I]IPT SPECT before and after treatment with serotonin reuptake inhibitors

It has been suggested that dopamine as well as serotonin are associated with the pathophysiology of obsessive-compulsive disorder (OCD). 5-Hydroxytryptophan inhibits dopamine release in healthy persons as well as in patients with OCD, and serotonin tonic inhibition affects dopamine function in basal ganglia, indicating a close relationship between serotonin and the dopamine system. Using iodine-123-labeled N-(3-iodopropen-2-yl)-2 beta-carbomethoxy-3beta-(4-chlorophenyl) tropane ([(123)I]IPT) single photon emission computed tomography (SPECT), we investigated the dopamine transporter (DAT) density in the basal ganglia of patients with OCD. The test consists of two measurements before and after treatment with serotonin reuptake inhibitors (SRIs). Ten patients with OCD before and after treatment with SRIs were included. We performed brain SPECT 2 h after intravenous administration of [(123)I]IPT using a dual-head SPECT camera (Vertex, ADAC, Calif., USA) and analyzed the SPECT data, reconstructed for the assessment of the specific/nonspecific DAT binding ratio in the basal ganglia. We then examined the correlation between the scores of OCD symptom changes, assessed with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), and DAT binding ratio. Patients with OCD after treatment with SRIs showed a significantly decreased DAT binding ratio in the right basal ganglia compared with baseline. A significant correlation was found between the total scores and compulsion score changes of the Y-BOCS and the changes of the DAT binding ratio of the right basal ganglia. These findings suggest that the dopaminergic neurotransmitter system of the basal ganglia could play an important role in the symptom improvement of OCD patients.

Infantile spasm-associated microencephaly in tuberous sclerosis complex and cortical dysplasia

OBJECTIVE

In children with and without infantile spasms, this study determined brain volumes and cell densities in epilepsy surgery patients with tuberous sclerosis complex (TSC) and cortical dysplasia with balloon cells (CD).

METHODS

We compared TSC (n = 18) and CD (n = 17) patients with normal/autopsy controls (n = 20) for MRI gray and white matter volumes and neuronal nuclei (NeuN) cell densities.

RESULTS

In patients without a history of infantile spasms, TSC cases showed decreased gray and white matter volumes (-16%). In cases with a history of infantile spasms, both CD (-25%) and TSC (-35%) patients showed microencephaly. This was confirmed in monozygotic twins with TSC, where the twin with a history of spasms had cerebral volumes less (-16%) than the twin without a history of seizures. Regardless of seizure history, TSC patients showed decreased NeuN cell densities in lower gray matter (-36%), whereas CD patients had increased densities in upper cortical (+52%) and white matter regions (+65%). For TSC patients, decreased lower gray matter NeuN densities correlated with reduced MRI volumes.

CONCLUSIONS

Patients with tuberous sclerosis without spasms showed microencephaly associated with decreased cortical neuronal densities. In contrast, cortical dysplasia patients without spasms were normocephalic with increased cell densities. This supports the concept that tuberous sclerosis and cortical dysplasia have different pathogenetic mechanisms despite similarities in refractory epilepsy and postnatal histopathology. Furthermore, a history of infantile spasms was associated with reduced cerebral volumes in both cortical dysplasia and tuberous sclerosis patients, suggesting that spasms or their treatment may contribute to microencephaly independent of etiology.

Enhanced expression of glutamate decarboxylase 65 improves symptoms of rat parkinsonian models

In this study, we report the amelioration of parkinsonian symptoms in rat Parkinson's disease (PD) models, as a result of the expression of glutamate decarboxylase (GAD) 65 with a modified cytomegalovirus (CMV) promoter. The transfer of the gene for gamma-amino butryic acid (GAD), the rate-limiting enzyme in gama-amino butrylic acid (GABA) production, has been investigated as a means to increase inhibitory synaptic activity. Electrophysiological evidence suggests that the transfer of the GAD65 gene to the subthalamic nucleus (STN) can change the excitatory output of this nucleus to inhibitory output. Our in vitro results also demonstrated higher GAD65 expression in cells transfected with the JDK promoter, as compared to cells transfected with the CMV promoter. Also, a rat PD model in which recombinant adeno-associated virus-2 (rAAV2)-JDK-GAD65 was delivered into the STN exhibited significant behavioral improvements, as compared to the saline-injected group. Interestingly, we observed that these behavioral improvements were more obvious in rat PD models in which rAAV2-JDK-GAD65 was injected into the STN than in rat PD models in which rAAV2-CMV-GAD65 was injected into the STN. Moreover, according to electrophysiological data, the rAAV2-JDK-GAD65-injected group exhibited more constant improvements in firing rates than did the rAAV2-CMV-GAD65-injected group. These data indicate that the JDK promoter, when coupled with GAD65 expression, is more effective with regard to parkinsonian symptoms than is the CMV promoter.

Differential gene expression profiling in aggressive bladder transitional cell carcinoma compared to the adjacent microscopically normal urothelium by microdissection-SMART cDNA PCR-SSH

Identifying novel and known genes that are differentially expressed in aggressive bladder transitional cell carcinoma (BTCC) has important implications in understanding the biology of bladder tumorigenesis and developing new diagnostic and therapeutic agents. In this study we identified the differential gene expression profiles comparing tumor to the adjacent microscopically normal mucosa by manual microdissection on frozen sections. The RNAs extracted from microdissected tissues were amplified by SMART cDNA PCR technology to generate forward subtractive cDNA library by suppressive subtractive hybridization (SSH). We obtained 376 positive clones, one hundred clones of aggressive BTCC subtracted cDNA library were selected at random and inserts were reamplified by PCR. After differential screening by reverse dot blotting, 73 positive clones, that contend inserts putatively upregulated in aggressive BTCC, were further analysed by DNA sequencing, GenBank and EST database searching. Sequencing results showed that 66 clones stand for 23 known genes and 7 clones for three new EST (Genbank number: DN236875, DN236874 and DN236873). In conclusion, microdissection-SMART cDNA PCR-SSH allowed for an efficient way to identify aggressive BTCC-specific differential expressed genes that may potentially be involved in the carcinogenesis and/or progression of aggressive BTCC. These differentially expressed genes may be of potential utility as therapeutic and diagnostic targets for aggressive BTCC.

Prevention of uncuffed hemodialysis catheter-related bacteremia using an antibiotic lock technique: A prospective, randomized clinical trial

As a result of the high rate of infection, the NKF-K/DOQI guidelines recommended that an uncuffed catheter (UC) should not be used for longer than three weeks. However, the findings of the Dialysis Outcomes and Practice Patterns Study recognized that 48% of new hemodialysis patients in the US and 75% in Europe used UC for temporary access during arteriovenous fistula or graft maturation. The antibiotic lock technique (ALT) has been recommended to prevent catheter-related bacteremia (CRB). Here, we prospectively evaluated the efficacy of catheter-restricted filling using an antibiotic lock solution in preventing CRB. A total of 120 new hemodialysis patients requiring a temporary catheter while waiting for placement and maturation of an arteriovenous fistula or graft were enrolled in this study. Patients with a UC were randomly assigned to receive either an antibiotic-heparin lock solution (antibiotic group: cefazolin 10 mg/ml, gentamicin 5 mg/ml, heparin 1000 U/ml) or a heparin lock solution (no-antibiotic group: heparin 1000 U/ml) as a catheter lock solution during the interdialytic period. The end point of the trial was CRB. CRB developed in seven (11.7%) patients in the no-antibiotic group (Staphylococcus aureus, two; Staphylococcus epidermidis, five) whereas only one patient in the antibiotic group had S. aureus bacteremia. CRB rates per 1000 catheter-days were 0.44 in the antibiotic group versus 3.12 in the no-antibiotic group (P=0.031). Kaplan-Meier analysis also showed that mean CRB-free catheter survival of 59 days (95% CI, 58-61 days) in the antibiotic group was greater than that in the no-antibiotic group (55 days; 95% CI, 50-59 days). The results suggest that ALT may be a beneficial means of reducing the CRB rate in hemodialysis patients with UC.

The behavioral effect of human mesenchymal stem cell transplantation in cold brain injured rats

We investigated the effect of stereotaxically transplanted human mesenchymal stem cells (hMSCs) on behavioral change after traumatic cold brain injury in adult rats. Cortical lesions (n= 20) were induced by touching a metal stamp, cooled with liquid nitrogen, to the dura over the forelimb motor cortex of adult rats. The procedure produced a localized lesion, and the animals showed significant motor deficits. hMSCs were freshly isolated from human iliac bone and cultured in tissue culture flasks with 10 ml Dulbecco's modified Eagle's medium. The animals received hMSC grafts (3 x 10(5) hMSCs) 6 days after cold lesion (n = 10). All rats were sacrificed 3 or 7 weeks after cold injury, and immunohistochemical staining was performed on brain sections to identify donor hMSCs. Neurological evaluations were performed with the forepaw adjusting step test and modified neurological scoring. Treatment with 3 x 10(5) hMSCs improved the rat's neurological functions. We also found that the transplanted cells successfully migrated into the injured brain, preferentially localized around the injury site, and expressed the neuronal and astrocyte marker. These data suggest that hMSCs may be a potential therapeutic tool for brain injuries.

Electrical stimulation of the anterior cingulate cortex in a rat neuropathic pain model

BACKGROUND

Electrical stimulation is currently employed to treat several neurological conditions, including pain and Parkinson's disease. It is one of several minimally invasive alternatives to drug treatments for painful conditions. A number of studies have shown that the anterior cingulate cortex (ACC) plays an important role in the processing of pain and pain modulation. The purpose of this study is to investigate these neuropathic pain-relieving effects by delivering electrical stimulation into the ACC of rat models.

METHODS

Following the approval of the AAALAC and the Guidelines and Regulations for Use and Care of Animals in Yonsei University, rats were subjected to surgery under pentobarbital anesthesia (50 mg/kg, i.p.) to produce neuropathic pain. Electrodes were bilaterally implanted into the ACC with a metal holder for the electrical stimulation. The effect of the electrical stimulation of the ACC on the rat neuropathic pain model was measured by the von Frey test.

FINDINGS

The effect of electrical stimulation of the ACC on neuropathic pain was shown during stimulation at 30, 40, 50, and 60 min, and at 10 min after stimulation. In the pain ACC stimulation group, the response of mechanical allodynia was significantly reduced during the time of ACC electrical stimulation.

CONCLUSION

The mechanical allodynia of the neuropathic pain could be modulated by ACC electrical stimulation.

Molecular pathology of low malignant bladder transitional cell carcinoma: a current perspective

Bladder transitional cell carcinoma (BTCC) actually has two phenotypes: low malignant and aggressive. Most previous molecular and cytogenetic analyses of bladder cancer were focused on aggressive BTCC. Little is known about the events that lead to the development of low malignant BTCC. This review mainly introduces the concept of two types of bladder tumors and then focuses on the molecular pathology of low malignant BTCC in particular. It is hoped that further understanding of the molecular pathology of low malignant BTCC may provide novel therapies and many other clinical benefits in patients with this disease.

Cysticercosis of cerebellopontine cistern: differential diagnosis using MRI

We report an example of subarachnoid neurocysticercosis located in the left cerebellopontine cistern of a 60 year-old man. The negative results of the serum and cerebrospinal fluid tests for parasites and the unusual MRI findings, such as the uncommon shape, location and extension pattern, made differential diagnosis difficult. Neurocysticercosis was confirmed by surgical and histopathological findings. The clinical and radiographic features of neurocysticercosis are highly variable. In an endemic area, neurocysticercosis should be considered in the differential diagnosis.

Effect of subthalamic lesion with kainic acid on the neuronal activities of the basal ganglia of rat parkinsonian models with 6-hydroxydopamine

The aim of the present study was to investigate the alteration of neuronal activities in the substantia nigra pars reticulata (SNpr) and globus pallidus (GP), after ipsilateral STN lesioning by kainic acid in the rat hemi-parkinsonian 6-hydroxydopamine (6-OHDA) model. In various rat Parkinson's disease (PD) models, an increase in the SNpr firing rate was observed, despite the occurrence of bursting patterns, and subthalamic lesion was found to reduce the mean firing rates and the percentage of bursting neurons in the SNpr. However, the relative proportion of bursting neurons, among all GP neurons, was slightly increased as a result of the subthalamic lesion. The significance of bursting activity in the SNpr and GP remains obscure. Further study is necessary to elucidate the pathophysiological mechanism behind Parkinson's disease.

Simple bone cyst occurring in calvarium

A 60 year-old female presented with a non-specific headache that she had experienced for 4 years. A simple skull X-ray indicated a well-defined, lobulated and radiolucent lesion with a thin sclerotic rim involving the parietal bone (Fig. 1A). Computed tomography revealed a hypodense lesion. Magnetic resonance imaging showed a 2 cm-sized cystic lesion in the diploic space with both tabular involvement. This lesion was not enhanced by contrast agent. It was well defined and the periosteum was intact. The cyst paralleled the CSF in signal intensity on all pulse sequences. No fluid levels were detected (Fig. 1B, C, D). After the scalp was incised, a semi-translucent and light yellow- to white-coloured bony lesion was easily identified. The outer bony cortex of this lesion was slightly elevated, and the consistency was same as that of the normal skull. A craniectomy was performed and the cystic skull lesion was removed. The inner surface of this cystic lesion was intact but appeared irregular. The cystic cavity was empty and the dura did not appear to be involved. Histologically, it was a simple cystic cavity without lining epithelium, and the surrounding bony structures were normal (Fig. 1E, F). It was diagnosed as a simple bone cyst (SBC). The postoperative course was uneventful.

Anterior cingulotomy for refractory obsessive-compulsive disorder

OBJECTIVE

This study was designed to prospectively investigate the efficacy and cognitive adverse effects of stereotactic bilateral anterior cingulotomy as a treatment for refractory obsessive-compulsive (OCD) patients for 12 months.

METHOD

Patients were eligible if they had severe OCD and rigorous treatments had been unsuccessful. Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), Clinical Global Impression (CGI) and neuropsychological tests were used to assess the efficacy and cognitive changes of cingulotomy before and 12 months after operation.

RESULTS

The mean improvement rate of the Y-BOCS scores achieved from baseline was 36.0%. Out of 14 patients six met responder criteria; 35% or higher improvement rate on Y-BOCS and CGI improvement of very much or much better at 12-month follow-up. There was no significant cognitive dysfunction after cingulotomy.

CONCLUSION

Anterior cingulotomy shows few cognitive adverse effects, with about half of the OCD patients demonstrating significant symptomatic improvement.

Complications after gamma knife radiosurgery for benign meningiomas

OBJECTIVES

To analyse the results of gamma knife radiosurgery (GKS) for the treatment of intracranial meningiomas and to assess possible factors related to the outcome and complications of such treatment.

METHODS

The authors retrospectively reviewed the clinical and radiological data of 179 patients (194 lesions) treated with GKS for meningiomas between May 1992 and October 2000. The mean follow up duration was 37.3 months (range 6.4 to 86.3 months). The study determined the correlation between radiosurgical outcome including imaging changes after GKS and multiple factors such as tumour location and size, patient characteristics, venous sinus status, pre-GKS degree of oedema, other treatment modalities, and radiosurgical parameters.

RESULTS

The radiological control rate was 97.1%. Magnetic resonance imaging (MRI) showed complications after GKS in 35 lesions (25.0%) among the 140 lesions followed up with MRI. Complications were divided into peritumorous imaging changes (33 lesions; 23.6%) and transient cranial nerve dysfunction (two lesions; 1.4%). Radiation induced imaging changes were seen mostly in convexity, parasagittal, and falx meningiomas that were deeply embedded in the cortex. About 60% of these were asymptomatic and the overall rate of symptomatic imaging changes was 9.3%. Neurological deficit related to imaging changes developed in only three patients, and all the symptoms were transient.

CONCLUSION

GKS for intracranial meningiomas seems to be a safe and effective treatment. However, meningiomas of the convexity, parasagittal region, or falx cerebri have a higher incidence of peritumorous imaging changes after GKS than those of the skull base. Therefore, the use of GKS needs to be considered very cautiously in cerebral hemispheric meningiomas, taking into consideration patient age and general condition, tumour size and location, pattern of cortical embedding, relation between the tumour and venous sinuses, presenting symptoms, and patient preference.

Neurophysiological identification and characterization of thalamic neurons with single unit recording in essential tremor patients

This study investigated the characteristics of the neuronal activities of the motor thalamus (Vim and Vop) in essential tremor (ET) patients, and compared the results with those of Parkinson's disease (PD) patients. The kinetic (Ki) neurons were found mainly in the Vim, whereas the voluntary (Vo) neurons were found principally in the Vop of ET patients. The mean firing rates of the ET patients were higher than those of the PD patients. In addition, the mean firing rates of the Ki neurons of the ET patients were higher than those of the PD patients in the Vim nuclei. However, the mean firing rates of the ventralis caudalis (Vc) neurons, which respond to sensory stimulation, were similar in each group. An analysis of the incidence of bursting neurons revealed that the Vop nucleus of the ET patients had less bursting neurons than the PD patients. However, in the Vim nucleus, both groups possessed bursting neurons even though the incidence was slightly different. Tremor cells were observed less frequently in the Vim nucleus of ET patients than in the PD patients. This study demonstrated the characteristic features of the neuronal activities of ET patients compared to those of PD patients.

Microvascular decompression for hemifacial spasm: a long-term follow-up of 1,169 consecutive cases

We analyzed the records of 1,169 patients with hemifacial spasm (HFS) who underwent microvascular decompression (MVD) and were followed up for more than 6 months from January 1987. The mean follow-up duration was 23.8 months (6-145 months). Excellent surgical outcome was obtained in 90.5% and good in 4.5%, giving an overall success rate of 95.0%. There was statistically significant relationship between vertebral artery (VA) shift and side of symptom. Permanent facial weakness and hearing impairment were 1.4% and 2.3%, respectively. There were no anatomical differences at the root entry zone (REZ) and significant differences of surgical outcome in young HFS (34 patients). Factors such as type of offender, severity of compression on the facial nerve root, and the degree of decompression of the REZ on postoperative MRI did not correlate with surgical outcome.

Gamma knife radiosurgery for metastatic brain tumors

We reviewed our series of metastatic brain tumors treated by Gamma Knife Radiosurgery. From May 1992 to January 2001, 115 consecutive patients with 425 lesions were treated over 128 treatment sessions. Forty three patients were known to have died at the end of the recording period. The mean follow-up duration was 11.6 months and mean number of lesions was 3.5. The most common primary sites were lung and breast. Mean tumor volume was 4.2 cm(3) and mean margin dose was 16.2 Gy. 6-month, 1-year, and 18-month survival rates were 73.6, 58, and 46%, respectively. Multivariate analysis revealed that higher KPS scores, no evidence of extracranial metastasis, and controlled primary disease were significantly related to longer survival. Adjuvant whole brain irradiation did not significantly influence on the prolongation of survival time and local control of radiosurgically treated lesions.