bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of loss of heterozygosity for chromosome 10 in patients with malignant astrocytic tumors: correlation with patient age and survival
Authors: Tada Kenji , Shiraishi Shoji , Kamiryo Takanori , Nakamura Hideo , Hirano Hirofumi , Kuratsu Jun-Ichi , Kochi Masato , Saya Hideyuki , Ushio Yukitaka 
Published: May 2009

Object. The most frequent genetic abnormality in human malignant gliomas is loss of heterozygosity (LOH) on chromosome 10. Candidate genes on chromosome 10 that are associated with the prognosis of patients with anaplastic astrocytoma (AA) and glioblastoma (GBM) were evaluated.
Methods. The authors used 12 fluorescent microsatellite markers on both arms of chromosome 10 to study LOH in 108 primary astrocytic tumors. The LOH on chromosome 10 was observed in 11 (32%) of 34 AAs and 34 (56%) of 61 GBMs. No LOH was detected in 13 low-grade gliomas. Loss of heterozygosity was not detected in any AA in the seven patients younger than 35 years, but it was discovered in 41% of the patients older than 35 years. The prognostic significance of LOH at each locus was evaluated in 89 patients older than 15 years; 33 (37%) had supratentorial AAs and 56 (63%) had supratentorial GBMs. The Cox proportional hazards model, adjusted for patient age at surgery, the preoperative Karnofsky Performance Scale score, and the extent of surgical resection revealed that LOH on marker D10S209 near the FGFR2 and DMBT1 genes was significantly associated with shorter survival in patients with AA. The LOH on markers D10S215 and D10S541, which contain the PTEN/MMAC1 gene between them, was significantly associated with shorter survival in patients with GBM.
Conclusions. In the present study it is found that LOH on chromosome 10 is an age-dependent event for patients with AAs and that LOH on marker D10S209 near the FGFR2 and DMBT1 loci is a significantly unfavorable prognostic factor. It is also reported that LOH on the PTEN/MMAC1 gene is a significantly unfavorable prognostic factor in patients with GBM.
Attenuation of intracerebral hemorrhage and thrombin-induced brain edema by overexpression of interleukin-1 receptor antagonist
Authors: Masada Tetsuya , Hua Ya , Xi Guohua , Yang Guo-Yuan , Hoff Julian T. , Keep Richard F. 
Published: May 2009

Object. Adenovirus-mediated overexpression of interleukin-1 receptor antagonist (IL-1ra) attenuates the inflammatory reaction and brain injury that follows focal cerebral ischemia. Recently, an inflammatory reaction after intracerebral hemorrhage (ICH) was identified. In this study the authors examine the hypothesis that overexpression of IL-1ra reduces brain injury (specifically edema formation) after ICH.
Methods. Adenoviruses expressing IL-1ra (Ad.RSVIL-1ra) or LacZ, a control protein (Ad.RSVlacZ), or saline were injected into the left lateral cerebral ventricle in rats. On the 5th day after virus injection, 100 µl of autologous blood or 5 U thrombin was infused into the right basal ganglia. Rats with ICH were killed 24 or 72 hours later for measurement of brain water and ion content. Thrombin-treated rats were killed 24 hours later for edema measurements and an assessment of polymorphonuclear leukocyte (PMNL) infiltration by myeloperoxidase (MPO) assay, as well as histological evaluation. Compared with saline-treated and Ad.RSVlacZ—transduced controls, Ad.RSVIL-1ra-transduced rats had significantly attenuated edema in the ipsilateral basal ganglia 3 days after ICH (81.5 ± 0.3% compared with 83.4 ± 0.4% and 83.3 ± 0.5% in control animals). Thrombin-induced brain edema was also reduced in Ad.RSVIL-1ra—treated rats (81.3 ± 0.4% compared with 83.2 ± 0.4% and 82.5 ± 0.4% in control rats). The reduction in thrombin-induced edema was associated with a reduction in PMNL infiltration into the basal ganglia, as assessed by MPO assay (49% reduction) and histological examination.
Conclusions. Overexpression of IL-1ra by using an adenovirus vector attenuated brain edema formation and thrombin-induced intracerebral inflammation following ICH. The reduction in ICH-induced edema with IL-1ra may result from reduction of thrombin-induced brain inflammation.
Effect of absorbable topical hemostatic agents on the relaxation time of blood: an in vitro study with implications for postoperative magnetic resonance imaging
Authors: Spiller Marga , Tenner Michael S. , Couldwell William T. 
Published: May 2009

Object. Absorbable topical hemostatic agents are commonly used in neurosurgery. In this study the authors examine the longitudinal relaxation time (T1) of blood in contact with these agents over time, measured in vitro, to determine if their presence could affect the interpretation of postoperative magnetic resonance (MR) images.
Methods. Coagulated and anticoagulated blood were used, both oxygenated and deoxygenated. The effects of a collagen-based agent (Collastat) and a cellulose-based agent (Surgicel) on the pH and T1 values of blood and on those of saline (used as a control) were investigated. The T1 was measured as a function of magnetic field strength and time by using a field-cycling relaxometer. This instrument measures 1/T1, the rate of T1, from which the T1 value is computed. The T1 values of blood were compared with those of hemostat-induced blood clots and with those of both gray and white matter of the brain. Signal changes on T1-weighted MR images were predicted on the basis of altered T1 values in vitro. Postoperative images were visually examined for the predicted changes. With the addition of Surgicel, blood had decreased pH and significantly shortened T1 at all fields, essentially within minutes, although it affected the T1 of saline only minimally. The effect of Surgicel increasingly shortened the T1 for 4 days in oxygenated blood. Collastat had no significant effect. The presence of some paramagnetic methemoglobin in Surgicel-induced clots was demonstrated using the relaxometer at a time when diamagnetic oxyhemoglobin would be present in naturally occurring blood clots. A bright signal that could mimic residual tumor on contrast-enhanced images was predicted and confirmed on postoperative T1-weighted MR images obtained in patients in whom Surgicel lined the tumor bed. It was not present in cases in which Surgicel was not used.
Conclusions. Surgicel alters the appearance of early postoperative MR images. To avoid misinterpretation, clinicians should be aware of this phenomenon.
Intercenter variance in clinical trials of head trauma—experience of the National Acute Brain Injury Study: Hypothermia
Authors: Clifton Guy L. , Choi Sung C. , Miller Emmy R. , Levin Harvey S. , Smith Kenneth R. , Muizelaar J. Paul , Wagner Franklin C. , Marion Donald W. , Luerssen Thomas G. 
Published: May 2009

Object. In a recently conducted trial of hypothermia in patients with severe brain injury, differences were found in the effects of hypothermia treatment among various centers. This analysis explores the reasons for such differences.
Methods. The authors reviewed data obtained in 392 patients treated for severe brain injury. Prerandomization variables, critical physiological variables, treatment variables, and accrual methodologies were investigated among various centers. Hypothermia was found to be detrimental in patients older than the age of 45 years, beneficial in patients younger than 45 years of age in whom hypothermia was present on admission, and without effect in those in whom normothermia was documented on admission. Marginally significant differences (p < 0.054) in the intercenter outcomes of hypothermia-treated patients were likely the result of wide differences in the percentage of patients older than 45 years of age and in the percentage of patients in whom hypothermia was present on admission among centers. The trial sensitivity was likely diminished by significant differences in the incidence of mean arterial blood pressure (MABP) less than 70 mm Hg (p < 0.001) and cerebral perfusion pressure (CPP) less than 50 mm Hg (p < 0.05) but not intracranial pressure (ICP) greater than 25 mm Hg (not significant) among patients in the various centers. Hours of vasopressor usage (p < 0.03) and morphine dose (p < 0.001) and the percentage of dehydrated patients varied significantly among centers (p < 0.001). The participation of small centers increased intercenter variance and diminished the quality of data.
Conclusions. For Phase III clinical trials we recommend: 1) a detailed protocol specifying fluid and MABP, ICP, and CPP management; 2) continuous monitoring of protocol compliance; 3) a run-in period for new centers to test accrual and protocol adherence; and 4) inclusion of only centers in which patients are regularly randomized.
Surgical seeding of chordomas
Authors: Arnautović Kenan I. , Al-Mefty Ossama 
Published: May 2009

Object. Chordomas have a high propensity for local recurrence and progression, as well as for systemic and cerebrospinal fluid metastasis. The authors identified and analyzed a series of patients with chordomas, focusing on an underrecognized pathological entity—surgical seeding of tumor cells.
Methods. In a retrospective analysis of 82 patients with chordomas treated over a 10-year period (1990–2000), the authors found six patients (7.3%) in whom surgical seeding had occurred. In five (83%) of these patients the primary tumor was located at the clivus. In one (17%), the tumor was present at the cervical spine. There were two male (33%) and four female patients (67%) whose mean age was 34 years. The seeding sites, which were separate from the primary tumor, were located along the operative route or in the abdomen where fat was removed. The seeding was diagnosed 5 to 15 months (mean 12 months) after surgery. One seeding site was present in five patients, and 17 seeding sites were present in one patient. The involved tissues included mucosa, bone, dura, muscle, and fat. After resection, all seedings were confirmed histologically.
Conclusions. Seeding of chordomas occurs along the operative route and at distant locations where tissue is harvested. Early diagnosis and aggressive surgery are recommended. Based on the results of this study, the authors suggest that surgical techniques, postoperative radiotherapy, neuroradiological follow-up protocol, and even research on chordomas should be reevaluated.
Chordomas of the craniocervical junction: follow-up review and prognostic factors
Authors: Colli Benedicto O. , Al-Mefty Ossama 
Published: May 2009

Object. Chordomas are rare tumors that arise from the remnants of the notochord. Because of their deep location, local infiltrative nature, and involvement of surrounding bone, treatment of chordomas is a challenge. In this study the authors analyze the data and prognostic factors obtained during the follow-up period (range 1–150 months, median 38 months) in 53 patients with craniocervical junction chordomas and 10 patients with chondrosarcomas.
Methods. Several surgical approaches were used, and some tumor excisions required staged procedures. Survival was calculated according the Kaplan—Meier method. Statistical analysis was performed using Fisher exact, log rank and Kruskal—Wallis tests. Radical/subtotal resection was achieved in 77.8% of the patients. The mortality rate during the follow-up period was 14.3%. In patients harboring chondrosarcoma better 5-year recurrence-free survival (RFS) rates were demonstrated than in those with chordoma (100% and 50.7%, respectively). Histological patterns (typical or chondroid chordomas) and patient age at onset of symptoms had no effect on the RFS rates. Radical/subtotal resections were associated with better RFS rates than partial resection. Adjuvant proton-beam therapy was shown to increase the RFS rates compared with conventional radiotherapy (90.9% and 19.4%, respectively, at 4 years posttreatment). Karyotypically abnormal tumors were associated with the worst RFS rates compared with karyotypically normal lesions (44.5% and 90.3%, respectively, at 3 years). Cases of cranial nerve palsy followed by those with cerebrospinal fluid leakages were the most frequent postoperative complications. Permanent postoperative neurological deficit was observed in 28.6% of the patients.
Conclusions. A better prognosis was observed in patients with chondrosarcoma compared with those harboring chordoma. Histological pattern and patient age at symptom onset were not factors that influenced prognosis in cases of chordoma. Extensive resection and possibly adjuvant proton-beam therapy provided better prognoses for these patients.
Contemporary psychosurgery and a look to the future
Authors: Feldman Robert P. , Alterman Ronald L. , Goodrich James T. 
Published: May 2009

Object. Despite a long and controversial history, psychosurgery has persisted as a modern treatment option for some severe, medically intractable psychiatric disorders. The goal of this study was to review the current state of psychosurgery.
Methods. In this review, the definition of psychosurgery, patient selection criteria, and anatomical and physiological rationales for cingulotomy, subcaudate tractotomy, anterior capsulotomy, and limbic leukotomy are discussed. The historical developments, modern procedures, and results of these four contemporary psychosurgical procedures are also reviewed. Examples of recent advances in neuroscience indicating a future role for neurosurgical intervention for psychiatric disease are also mentioned.
Conclusions. A thorough understanding of contemporary psychosurgery will help neurosurgeons and other physicians face the ethical, social, and technical challenges that are sure to lie ahead as modern science continues to unlock the secrets of the mind and brain.
Recording nasal muscle F waves and electromyographic activity of the facial muscles: a comparison of two methods used for intraoperative monitoring of facial nerve function
Authors: Wedekind Christoph , Klug Norfrid 
Published: May 2009

Object. A comparison of two electrophysiological methods used to assess facial nerve function intraoperatively was conducted in 33 patients with tumors of the cerebellopontine angle.
Methods. All 33 patients had presented with normal facial nerve function preoperatively. After general anesthesia had been induced by a mixture of midazolam and fentanyl, continual online EMG recordings from the orbicularis oculi and oris muscles were alternated with nasal muscle F-wave recordings. Facial nerve outcomes, assessed using a modified House—Brackmann scale, varied among good (48%), moderate (18%), and poor (33%). Analysis of electromyographic (EMG) data resulted in a significant correlation between the finding of only transient manipulation-evoked activity and a good outcome, whereas in cases in which there was poor outcome, an increase in the amplitude or duration of ongoing activity was detected. A permanent loss of nasal muscle F waves specifically appeared to indicate a severe dysfunction of the facial nerve that was linked to a poor outcome. All patients with latency and/or amplitude changes or even a transient loss of the F wave achieved good or moderate facial nerve outcomes. A transient loss of the F wave, however, was detected significantly more frequently in patients with moderate outcomes. None of these patients exhibited normal facial function (House—Brackmann Grade I) postoperatively.
Conclusions. Online EMG monitoring can provide some information on imminent or even present damage to the facial nerve intraoperatively. The diagnostic sensitivity, specificity, and positive predictive values of a permanent F-wave loss, however, are much higher than those of EMG monitoring. Additionally, this loss of the F wave is supposed to be transient if the surgical procedure is stopped until the F wave recovers. Therefore, F-wave monitoring serves to alert the surgeon that the facial nerve is about to receive a lesion.
Radiosurgery performed with the aid of a 3-mm collimator in the subthalamic nucleus and substantia nigra of the vervet monkey
Authors: De Salles Antonio A. F. , Melega William P. , Laćan Goran , Steele Lisa J. , Solberg Timothy D. 
Published: May 2009

Object. Radiosurgery for functional neurosurgery performed using a linear accelerator (LINAC) has not been extensively characterized in preclinical studies. In the present study, the properties of a newly designed 3-mm-diameter collimator were evaluated in a dedicated LINAC, which produced lesions in the basal ganglia of vervet monkeys. Lesion formation was determined in vivo in three animals by examining magnetic resonance (MR) images to show the dosedelivery precision of targeting and the geometry and extent of the lesions. Postmortem immunohistochemical studies were conducted to determine the extent of lesion-induced radiobiological effects.
Methods. In three male vervet monkeys, the subthalamic nucleus (STN; one animal) and the pars compacta of the lateral substantia nigra (SN; two animals) were targeted by a Novalis Shaped Beam Surgery System that included a 3-mm collimator and delivered a maximum dose of 150 Gy. Magnetic resonance images obtained 4, 5, and 9 months posttreatment were reviewed, and the animals were killed so that immunohistological characterizations could be made.
Conclusions. The generation of precise radiosurgical lesions by a 3-mm collimator was validated in studies that targeted the basal ganglia of the vervet monkey. The extent of the lesions created in all animals remained restricted in diameter (< 3 mm) throughout the duration of the studies, as assessed by reviewing MR images. Histological studies showed that the lesions were contained within the STN and SN target areas and that there were persistent increases in glial fibrillary acidic protein immunoreactivity. Increases in immunoreactivity for tyrosine hydroxylase, the serotonin transporter, and the GluR1 subunit of the α-amino-3-hydroxy-5-methyl-4-isoxazole propionate glutamate receptor in penumbral regions of the lesion were suggestive of compensatory neuronal adaptations. This radiosurgical approach may be of particular interest for the induction of lesions of the STN and SN in studies of experimental parkinsonism, as well as for the development of potential radiosurgical treatments for Parkinson disease.
Site-specific immune response to implanted gliomas
Authors: Proescholdt Martin A. , Merrill Marsha J. , Ikejiri Barbara , Walbridge Stuart , Akbasak Aytac , Jacobson Steven , Oldfield Edward H. 
Published: May 2009

Object. Immunotherapy for glioblastoma has been uniformly ineffective. The immunological environment of the brain, with its low expression of major histocompatibility complex (MHC) molecules and limited access for inflammatory cells and humoral immune effectors due to the blood—brain barrier (BBB), may contribute to the failure of immunotherapy. The authors hypothesize that brain tumors are protected from immune surveillance by an intact BBB at early stages of development. To investigate the immunological characteristics of early tumor growth, the authors compared the host response to a glioma implanted into the brain and into subcutaneous tissue.
Methods. Samples of tumors growing in the brain or subcutaneously in rats were obtained for 7 consecutive days and were examined immunohistochemically for MHC Class I & II molecules, and for CD4 and CD8 lymphocyte markers. Additionally, B7-1 costimulatory molecule expression and lymphocyte-specific apoptosis were examined.
Conclusions. On Days 3 and 4 after implantation, brain tumors displayed significantly lower MHC Class II expression and lymphocytic infiltration (p < 0.05). After Day 5, however, no differences were detected. The MHC Class II expressing cells within the brain tumors appeared to be infiltrating microglia. Minimal B7-1 expression combined with lymphocyte-specific apoptosis were detected in both brain and subcutaneous tumors. Low MHC Class II expression and low lymphocytic infiltration at early time points indicate the importance of the immunologically privileged status of the brain during early tumor growth. These characteristics disappeared at later time points, possibly because the increasing perturbation of the BBB alters the specific immunological environment of the brain. The lack of B7-1 expression combined with lymphocyte apoptosis indicates clonal anergy of glioma-infiltrating lymphocytes regardless of implantation site.
An MKM-mounted instrument holder for frameless point-stereotactic procedures: a phantom-based accuracy evaluation
Authors: Willems Peter W. A. , Noordmans Herke Jan , van der Sprenkel Jan Willem Berkelbach , Viergever Max A. , Tulleken Cees A. F. 
Published: May 2009

✓ To enable the use of the Mehrkoordinaten Manipulator (MKM) robotic navigation system for frameless point stereotactic procedures, a new instrument holder is presented. A phantom-based accuracy study was performed in which this new method was compared with frame-based procedures performed using the Brown-Roberts-Wells (BRW) stereotactic frame.
The authors acquired computerized tomography scans of a test phantom, consisting of 19 acrylic plastic target rods on a circular base. These images were used in frame-based (BRW) and frameless (MKM) localization experiments. In both cases the authors calculated the distances between the actual target positions and the positions reached stereotactically.
The mean application accuracy (target registration error) was 0.68 mm when the BRW frame was used and 0.96 mm when the MKM system was used after manual repositioning of the microscope (p < 0.001). Positioning accomplished using robotics only demonstrated a slightly larger inaccuracy: 1.47 mm (p < 0.005). Because the surgeon is concerned with the largest error in an individual case rather than the mean error in a large number of cases, the mean + three standard deviations was also compared. This value differed very little between the manually positioned MKM system and the BRW frame (2.04 mm and 1.84 mm, respectively). Although repeatability per target appeared to be slightly better when the BRW frame was used, accuracy was more homogeneous over the phantom volume when the MKM system was used (both differences were not significant).
In conclusion, the accuracy of point stereotactic procedures performed using an instrument holder attached to the MKM system is comparable with the accuracy of procedures involving a stereotactic frame. Moreover, the frameless techniques and robotic features of the MKM enable a more surgeon- and patient-friendly stereotactic procedure.
Prevalence of asymptomatic incidental aneurysms: review of 4568 arteriograms
Authors: Winn H. Richard , Jane John A. , Taylor James , Kaiser Donald , Britz Gavin W. 
Published: May 2009

Object. The prevalence of unruptured cerebral aneurysms is unknown, but is estimated to be as high as 5%. The goal of this study was to determine the prevalence of asymptomatic incidental aneurysms.
Methods. The authors studied all cerebral arteriography reports produced at a single institution, the University of Virginia, between April 1969 and January 1980. A review of 3684 arteriograms demonstrated 24 cases of asymptomatic aneurysms, yielding a prevalence rate of 0.65%. The majority (67%) of the 24 patients harboring unruptured aneurysms were women. More than 90% of the unruptured aneurysms were located in the anterior circulation and in locations similar to those found in patients with ruptured aneurysms. Nearly 80% of the aneurysms were smaller than 1 cm in their greatest diameter. The frequency of asymmetrical unruptured aneurysms (0.6–1.5%) was constant throughout all relevant age ranges (35–84 years).
Conclusions. While keeping in mind appropriate caveats in extrapolating from these data, the prevalence rate of asymptomatic unruptured aneurysms found in the present study allows an estimation of the yearly rate of rupture of these lesions. The authors suggest that this yearly rate of rupture falls within the range of 1 to 2%.