Thermalization of strongly coupled field theories.

Using the holographic mapping to a gravity dual, we calculate 2-point functions, Wilson loops, and entanglement entropy in strongly coupled field theories in d=2, 3, and 4 to probe the scale dependence of thermalization following a sudden injection of energy. For homogeneous initial conditions, the entanglement entropy thermalizes slowest and sets a time scale for equilibration that saturates a causality bound. The growth rate of entanglement entropy density is nearly volume-independent for small volumes but slows for larger volumes. In this setting, the UV thermalizes first.

Diazepam attenuates the post-traumatic hyperactivity of excitatory synapses in rat hippocampal CA1 neurons.

The effect of diazepam, a benzodiazepine derivative, on the post-traumatic hyperactivity of excitatory synaptic transmission was examined in rat hippocampal CA1 area. Optical recordings showed that the activity of hippocampal neurons was enhanced in rats treated with fluid percussion injury (FPI) as compared with that of sham-operated rats. The optical response was characterized by fast and slow components. FPI did not affect the fast component that reflects presynaptic action potentials, but enhanced the slow component that reflects excitatory synaptic responses. Intracellular recordings showed that the amplitude and duration of the excitatory postsynaptic potential (EPSP) were increased after FPI. However, FPI did not affect the resting membrane potential and action potentials of hippocampal neurons. Intraperitoneal (i.p.) administration of diazepam (30 and 90 min after FPI) attenuated the post-traumatic hyperactivity of the slow optical response. The slope of input-to-output relation of excitatory synapses was decreased by acute administration of diazepam to FPI rats, but not by delayed administration of diazepam (4 and 5 h after FPI). The fast optical responses were not affected by either FPI or i.p. administration of diazepam. These results suggest that administration of diazepam at early post-traumatic period prevents the FPI-induced delayed enhancement of excitatory synaptic transmission in rat hippocampal CA1 neurons.

Characteristics of cognitive function in patients after traumatic brain injury assessed by visual and auditory event-related potentials.

OBJECTIVE: Using auditory and visual stimuli including facial affective stimuli, we analyzed the P300 components of event-related potentials (ERPs) in patients after traumatic brain injury (TBI) to assess their cognitive characteristics. DESIGN: Twenty TBI patients and 32 age-matched control subjects were recruited. Using conventional oddball paradigms, visual ERPs were recorded using images of crying and smiling babies as visual stimuli. Auditory ERPs were obtained using 2-kHz tones as stimuli without affective stimuli. The peak amplitude and latency for P300, and the latency for N200, were recorded. RESULTS: : In visual ERPs, the P300 amplitudes were significantly smaller in patients than in controls for the crying baby, but the amplitudes were similar between groups for the smiling baby. Controls showed smaller P300 amplitudes for the smiling baby than for the crying baby, but patients showed no difference. In patients, the P300 latency for both smiling and crying babies was longer than in the controls. Patients' auditory ERPs showed smaller P300 amplitudes but similar P300 latencies compared with controls. The N200 latency in patients was significantly longer than in controls only for the crying baby. CONCLUSIONS: Visual ERPs are a potentially useful marker for evaluating cognitive dysfunction in patients after TBI.

Preoperative embolization of brain tumor with pial artery or dural branch of internal carotid artery as feeding artery.

SUMMARY: This study evaluated the clinical usefulness of preoperative embolization of the pial artery or dural branch of the internal carotid artery (ICA) for brain tumor. Subjects comprised 17 patients with large hypervascular brain tumors who underwent preoperative selective embolization. Micro-catheters (2- or 1.7-F) and shapeable hydrophilic micro-guide wires were used for pial artery (branching from the posterior or anterior cerebral artery) or ICA dural branch embolization. Embolization was performed under digital subtraction fluoroscopy with Polyvinyl alcohol (PVA) particles (150-250 mm) and/or liquid coil.Tumor resection was performed immediately or the day after embolization. Digital subtraction angiography (DSA) before and after endovascular devascularization, blood loss during tumor resection, and clinical outcome were evaluated. All endovascular procedures were technically successful. Post-embolization DSA revealed either a disappearance or a marked decrease of the tumor stain in all cases. Control of intraoperative bleeding was easily accomplished, and intraoperative blood loss was low. Preoperative particle embolization of the feeding artery from the cortical artery or ICA dural branch is safe and effective as adjuvant therapy before tumor resection.

Minimally invasive management of ependymoma of the aqueduct of Sylvius: therapeutic considerations and management.

A major concern in the neuroendoscopic approach to an intraventricular tumor is the histological confirmation from a limited biopsy. However, the effort to excise the whole bulk of the tumor should be made for the minimally invasive management of selected intraventricular tumors. The case of an adult male with focal aqueductal ependymoma who presented with the clinical syndrome of hydrocephalus is reported. This may be of particular interest because it represents the first case of aqueductal ependymoma that has been successfully treated with endoscopic surgery.

Clinical Outcomes of Coil Embolization for Acutely Ruptured Aneurysm. Comparison with Results of Neck Clipping when Coil Embolization is Considered the First Option.

SUMMARY: The purpose of this prospective study was to evaluate clinical results in patients with acutely ruptured cerebral aneurysm treated by neck clipping (NC) or coil embolization (CE) when CE was considered the first option. Between 1998 and 2003, 280 patients with acutely ruptured cerebral aneurysms excluding intracerebral hematoma were evaluated. Patients were managed prospectively according to the following protocol: primary treatment modality was CE (n=179). NC (n=101) was selected for the patients with aneurysms that were small (less than 2 mm) or an unsuitable shape for CE. Surgical complication rates were 4.5% for CE and 16.8% for NC. Symptomatic vasospasm occurred in 8.4% of CE patients and 29% of NC patients. Good recovery on the Glasgow Outcome Scale was achieved by 71% of CE patients and 50% of NC patients at discharge. Surgical complications and symptomatic vasospasm were significantly reduced in CE compared to NC. Clinical outcome at discharge was also better with CE. Although 18.3% of CE patients showed various degrees of aneurysmal recanalization and 7% of CE patients required additional treatment (re-CE or NC), aneurysmal rebleeding occurred in only one patient during followup (mean, 3.95 years).

Preoperative selective internal carotid artery dural branch embolisation for petroclival meningiomas.

We assessed the clinical value of preoperative embolisation of the dural branches of the internal carotid artery (ICA) in cases of petroclival meningioma was evaluated. We carried out preoperative selective embolisation on seven consecutive patients with large petroclival meningiomas, using nonbraided 2 F steam-shaped microcatheters and shapeable hydrophilic microguide-wires to enter the dural branches of the ICA. The embolisations were performed using digital subtraction fluoroscopy with 150-250 microm polyvinyl alcohol particles. The tumours were resected a few days after embolisation. We reviewed angiographic findings before and after endovascular devascularisation, blood loss during tumour resection and clinical outcome. All endovascular procedures were technically successful, and postembolisation angiography showed disappearance of or marked decrease in tumour stain in all cases. Intraoperative bleeding was easily controlled, and intraoperative blood loss was low.

Recognition of ADP-ribosylation factor 4-like by HLA-A2-restricted and tumor-reactive cytotoxic T lymphocytes from patients with brain tumors.

Although specific immunotherapy is one candidate treatment of brain tumor, the molecular basis of T-cell-mediated recognition of brain tumors has not yet been elucidated. In this study, we tried to identify brain tumor antigens using HLA-A2-restricted and tumor-reactive cytotoxic T lymphocytes (CTLs). As an HLA-A2-restricted OK-CTL line contained CTLs capable of responding to HLA-A2+ malignant glioma cells, this cell line was used for identification of brain tumor antigens. After screening a cDNA library from brain tumor cells, this CTL line was found to produce interferon (IFN)-gamma when cultured with COS-7 cells, which were cotransfected with both a cDNA clone (clone 1) and HLA-A0207 cDNA. Data base searches indicated that the clone 1 was 98% identical to that of the human ADP-ribosylation factor 4-like (ARF4L). Two peptides, ARF4L 15-24 and ARF4L 69-77, possessed the ability to induce HLA-A2-restricted and tumor-reactive CTLs from peripheral blood mononuclear cells of patients with brain tumors. Although ARF4L seemed to be ubiquitously expressed at the mRNA level, ARF4L-reactive CTLs failed to exhibit cytotoxicity against normal lymphoid blasts. These results indicate that these two ARF4L peptides could be targets for immunotherapy of HLA-A2+ patients with brain tumors.

[A case of primary Sjögren syndrome with repeated purpura].

In Sjögren syndrome, purpura is one of its various well known eruptions. Although this disease state is assumed to be based on hypergammaglobulinemia, the details of its mechanism are unknown. We experienced a case involving a female patient with primary Sjögren syndrome showing repeated purpura on the legs, and examined her blood viscosity and histopathology. This girl developed Sjögren syndrome and was admitted to our hospital at 12-years-old. She underwent steroid treatment because of aggravation of the xerosis state and prominent purpura on the legs. Hypergammaglobulinemia was improved during the course; however, purpura appeared repeatedly. Although her blood viscosity was slightly higher than normal, this had no relation to purpura and serum gamma globulin values. Skin biopsy revealed necrotizing angiitis. These results suggest that the purpura of this case was caused not only by hyperviscosity from the hypergammaglobulinemia but also involvement of vasculitis by the primary disease.

Therapeutic effect and mechanism of repetitive transcranial magnetic stimulation in Parkinson's disease.

The therapeutic effect of repetitive transcranial magnetic stimulation (rTMS) on clinical performance was assessed by a double-blind study in 9 patients with Parkinson's disease (PD). Nine other patients underwent sham stimulation as controls. The modified Hoehn and Yahr (H&Y) staging scale, the Schwab and England Activities of Daily Living (ADL) scale, and the Unified Parkinson's disease rating scale (UPDRS) were used to assess changes of clinical performance. Patients were assessed prior to and following 2 months of rTMS. In addition, the mechanism of rTMS was investigated by dopamine and homovanillic acid (HVA) in the lumbar cerebrospinal fluid (CSF) of 17 patients before and after therapeutic rTMS for three or four months. rTMS was applied manually to the frontal areas 60 times per session, i. e., 30 times per side using a large circular coil, a pulse intensity of 700 V, and a frequency of 0.2 Hz. Sessions were continued once a week for 2 months. The 9 control patients showed no changes of symptoms between the initial evaluation and that after 2 months of sham rTMS. In contrast, all 9 patients receiving rTMS showed a significant decrease of the modified H&Y and UPDRS scores after 2 months, while the Schwab and England ADL Scale scores increased significantly. In the second CSF sample from patients receiving rTMS, HVA showed a significant decrease These results suggest that rTMS is beneficial for the symptoms of Parkinson's disease and that it may act via inhibition of dopaminergic systems.

Production of platelet-activating factor by neuronal cells in the rat brain with cold injury.

The production and localization of platelet-activating factor (PAF) in the brain following focal brain injury were examined. Immunofluorescent staining was used to detect PAF in the rat brain with cold-induced local brain injury. After cold injury, immediate-early PAF staining was observed within the cold lesion followed later by immunoreactivity in the ipsilateral white matter. PAF immunoreactivity was also clearly seen both in cortical neurons adjacent to the cold lesion and in the ipsilateral hippocampus which showed delayed neuronal degeneration. The data suggest that PAF synthesis occurs in the neuronal cells in the perilesional area and hippocampus as well as within the cold lesion site during the early stages of cold-induced brain injury. PAF expression may contribute to the onset and progression of further brain damage, such as delayed axotomy and delayed neuronal loss.

Cervical myelopathy due to compression by bilateral vertebral arteries--case report.

A 69-year-old man presented with progressive cervical myelopathy due to vascular compression of the upper cervical spinal cord. Vertebral angiography and magnetic resonance imaging revealed that the elongated bilateral vertebral arteries (VAs) had compressed the spinal cord at the C-2 level. The spinal cord was surgically decompressed laterally by retracting the VAs with Gore-Tex tape and anchoring them to the dura. The patient's symptoms improved postoperatively. Decompression and anchoring of the causative vessels is recommended due to the large size of the VAs.

Acute focal demyelinating disease simulating brain tumors: histopathologic guidelines for an accurate diagnosis.

The object of the present study was to determine the histopathological guidelines for accurate diagnosis of cases of acute focal demyelinating disease that simulates brain tumors. The surgical pathology of three such cases is assessed. Histopathological keys to the diagnosis of such cases are as follows. First, a pattern of sheets of atypical gemistocytic astrocytes in the white matter that show well-formed processes and that are adequately distanced from each other argues against a diagnosis of neoplasm. Second, uniform distribution of foamy macrophages aligned along axons, with occasional focal collections surrounding blood vessels and in the absence of any associated coagulative necrosis argues against the presence of a tumor. Third, perivascular chronic inflammatory infiltration, especially a mixture of lymphocytes and macrophages, favors the diagnosis of demyelination plaque. In such cases the lymphocytes will be predominantly T cells. Fourth, pleomorphic astrocytic proliferation with a lack of vascular endothelial proliferation should raise the suspicion that the lesion may not be a brain tumor. These diagnostic keys should be followed when diagnosing cases that are suspected to be demyelination processes rather than brain tumors. The presence of demyelination plaque should then be confirmed by imaging modalities such as staining with myelin-and axon-specific stains.

The biochemical analysis of neurotransmitters in central neurocytomas.

Central neurocytomas are rare benign intraventricular tumours composed of small round synaptophysin-positive cells, suggesting a neuronal origin of these tumour cells. Although past electron microscopic studies demonstrated synaptic vesicles in the synapse of central neurocytomas, the kinds of neurotransmitters in central neurocytomas have never been identified. In this study we analyzed neurotransmitters in an attempt to clarify the tumorigenesis of central neurocytomas. We studied frozen central neurocytoma specimens from four patients. The tissue levels of glutamate and GABA (gamma-aminobutyric acid) in the tumours were determined by gas chromatography-mass spectrometry (GC-MS) using a selected ion monitoring method. The tissue levels of acetylcholine, choline, catecholamines and metabolites of catecholamines in the tumours were measured by high-performance liquid chromatography combined with electrochemical detection. Choline was found in extremely high concentration in all central neurocytomas when compared with levels in controls. In one central neurocytoma, GABA was found in extremely high concentration compared with controls. In all central neurocytomas, glutamate was found in lower or identical concentrations compared with controls. In all central neurocytomas and controls, dopamine and catecholamine concentrations were extremely low. These results indicated that the histogenesis of central neurocytomas begins with the subependymal stem cells, which have the potential to differentiate into cholinergic or GABA neurons.

Neurochemical monitoring in the management of severe head-injured patients with hypothermia.

The neuroprotective action and effect of hypothermia on the neurochemical system is not well understood. The present study was performed using six patients with GCS scores of 5 or less to clarify the relationship between monitored brain temperature, intracranial pressure (ICP), cerebral perfusion pressure (CPP) and oxygen saturation of the jugular venous blood (SjO2). Changes in concentration of excitatory amino acids, glutamate (GLU) and aspartate (ASP), and NO2 were studied using intracerebral microdialysis as well as in jugular venous blood and cerebrospinal fluid (CSF). Changes in brain temperature, CPP and SjO2 resulting from hypothermia and brain death associated with markedly higher concentrations of and fluctuations in the concentrations of GLU, ASP and NO2 were observed in the dialysate than in the jugular venous blood or CSF. Hypothermic treatment significantly reduces excitatory amino acid and NO2 concentrations, a finding which was associated with an improvement in CPP and SjO2. Measurement of GLU and ASP using intracerebral microdialysis is a clinically useful method for clarifying abnormal neurochemical events associated with severe head injury and for evaluating the effects of hypothermia.

Delayed CSF pseudocyst following shunt malfunction after myelomeningocele repair.

We report a case of delayed cerebrospinal fluid (CSF) pseudocyst following shunt malfunction in a 20-year-old patient with myelomeningocele. Magnetic resonance (MR) images and a radioimmunoassay shunt-gram detected the CSF fistula at the old scar of the myelomeningocele repaired 20 years before. Since the revision of the shunt system failed to keep the pseudocyst, the lesion was successfully directly repaired. Treatment of the delayed CSF pseudocyst following shunt malfunction thus requires a radical operation of the lesion.