bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of the peak troponin value to differentiate myocardial infarction from reversible neurogenic left ventricular dysfunction associated with aneurysmal subarachnoid hemorrhage
Authors: Bulsara Ketan R. , McGirt Matthew J. , Liao Lawrence , Villavicencio Alan T. , Borel Cecil , Alexander Michael J. , Friedman Allan H. 
Published: May 2009

Object. Differentiating myocardial infarction (MI) from reversible neurogenic left ventricular dysfunction (stunned myocardium [SM]) associated with aneurysmal subarachnoid hemorrhage (SAH) is critical for early surgical intervention. The authors hypothesized that the cardiac troponin (cTn) trend and/or echocardiogram could be used to differentiate between the two entities.
Methods. A retrospective study was conducted for the period between 1995 and 2000. All patients included in the study met the following criteria: 1) no history of cardiac problems; 2) new onset of abnormal cardiac function (ejection fraction [EF] < 40% on echocardiograms); 3) serial cardiac markers (cTn and creatine kinase MB isoform [CK-MB]); 4) surgical intervention for their aneurysm; and 5) cardiac output monitoring either by repeated echocardiograms or invasive hemodynamic monitoring during the first 4 days post-SAH when the patients were euvolemic.
Of the 350 patients with SAH, 10 (2.9%) had severe cardiac dysfunction. Of those 10, six were women and four were men. The patients' mean age was 53.5 years (range 29–75 years) and their SAH was classified as Hunt and Hess Grade III or IV. Aneurysm distribution was as follows: basilar artery tip (four); anterior communicating artery (two); middle cerebral artery (one); posterior communicating artery (two); and posterior inferior cerebellar artery (one). The mean EF at onset was 33%. The changes on echocardiograms in these patients did not match the findings on electrocardiograms (EKGs). Within 4.5 days, dramatic improvement was seen in cardiac output (from 4.93 ± 1.16 L/minute to 7.74 ± 0.88 L/minute). Compared with historical controls in whom there were similar levels of left ventricular dysfunction after MI, there was no difference in peak CK-MB. A 10-fold difference, however, was noted in cTn values (0.22 ± 0.25 ng/ml; control 2.8 ng/ml; p < 0.001).
Conclusions. The authors determined the following: 1) that the CK-MB trend does not allow differentiation between SM and MI; 2) that echocardiograms revealing significant inconsistencies with EKGs are indicative of SM; and 3) that cTn values less than 2.8 ng/ml in patients with EFs less than 40% are consistent with SM.
Comparison between perimesencephalic nonaneurysmal subarachnoid hemorrhage and subarachnoid hemorrhage caused by posterior circulation aneurysms
Authors: Alén Jose F. , Lagares Alfonso , Lobato Ramiro D. , Gómez Pedro A. , Rivas Juan J. , Ramos Ana 
Published: May 2009

Object. Some authors have questioned the need to perform cerebral angiography in patients presenting with a benign clinical picture and a perimesencephalic pattern of subarachnoid hemorrhage (SAH) on initial computerized tomography (CT) scans, because the low probability of finding an aneurysm does not justify exposing patients to the risks of angiography. It has been stated, however, that ruptured posterior circulation aneurysms may present with a perimesencephalic SAH pattern in up to 10% of cases. The aim of the present study was twofold: to define the frequency of the perimesencephalic SAH pattern in the setting of ruptured posterior fossa aneurysms, and to determine whether this clinical syndrome and pattern of bleeding could be reliably and definitely distinguished from that of aneurysmal SAH.
Methods. Twenty-eight patients with ruptured posterior circulation aneurysms and 44 with nonaneurysmal perimesencephalic SAH were selected from a series of 408 consecutive patients with spontaneous SAH admitted to the authors' institution. The admission unenhanced CT scans were evaluated by a neuroradiologist in a blinded fashion and classified as revealing a perimesencephalic SAH or a nonperimesencephalic pattern of bleeding.
Of the 28 patients with posterior circulation aneurysms, five whose grade was I according to the World Federation of Neurosurgical Societies scale were classified as having a perimesencephalic SAH pattern on the initial CT scan. The data show that the likelihood of finding an aneurysm on angiographic studies obtained in a patient with a perimesencephalic SAH pattern is 8.9%. Conversely, ruptured aneurysms of the posterior circulation present with an early perimesencephalic SAH pattern in 16.6% of cases.
Conclusions. This study supports the impression that there is no completely sensitive and specific CT pattern for a nonaneurysmal SAH. In addition, the authors believe that there is no specific clinical syndrome that can differentiate patients who have a perimesencephalic SAH pattern caused by an aneurysm from those without aneurysms. Digital subtraction angiography continues to be the gold standard for the diagnosis of cerebral aneurysms and should be performed even in patients who have the characteristic perimesencephalic SAH pattern on admission CT scans.
Effects of the Ca++-permeable nonselective cation channel blocker LOE 908 on subarachnoid hemorrhage—induced vasospasm in the basilar artery in rabbits
Authors: Kawanabe Yoshifumi , Masaki Tomoh , Hashimoto Nobuo 
Published: May 2009

Object. The Ca++ influx into vascular smooth-muscle cells (VSMCs) plays a fundamental role in the development and chronic effects of vasospasm after subarachnoid hemorrhage (SAH). The Ca++-permeable nonselective cation channels (NSCCs) are activated by several endothelium-derived constricting factors such as endothelin 1 (ET-1) and thromboxane A2. Moreover, the receptor-operated Ca++ channel blocker LOE 908 inhibits ET-1—induced extracellular Ca++ influx via NSCCs in the VSMCs of the basilar artery (BA) and the NSCC-dependent part of ET-1—induced vasoconstriction of BA rings. The purpose of the present study was to evaluate the in vivo role of LOE 908 on SAH-induced vasospasm.
Methods. Forty-two Japanese white rabbits were assigned to seven groups. Treatment groups consisted of the following: 1) control rabbits without SAH that received a cisternal injection of saline; 2) rabbits with SAH that were subjected to the intravenous administration of saline; 3 through 6) rabbits with SAH that underwent the intravenous administration of 0.01, 0.1, 1, or 10 mg/kg LOE 908, respectively; and 7) rabbits without SAH that underwent the intravenous administration of 10 mg/kg LOE 908. Autologous blood was injected into the cisterna magna. The caliber of the BA was measured on angiographic studies before and after the cisternal injection of autologous blood.
The intravenous injection of LOE 908 inhibited the magnitude of an SAH-induced vasosapsm. In addition, the concentration of LOE 908 required to relax vasospasm (1 mg/kg) correlated with that required to block Ca++ influx into VSMCs.
Conclusions. The Ca++ channel blocker LOE 908 may inhibit the magnitude of an SAH-induced vasospasm by blocking the influx of Ca++ through NSCCs in rabbit BAs. Blocking the NSCCs may represent a new treatment for cerebral vasospasm after SAH.
Stretching and breaking characteristics of cerebrospinal fluid shunt tubing
Authors: Tomes Daniel J. , Hellbusch Leslie C. , Alberts L. Russell 
Published: May 2009

Object. Cerebrospinal fluid (CSF) shunt system malfunction due to silastic tubing fracture necessitates revision surgery in shunt-dependent individuals. The goal of this study was to examine the mechanical stretching and breaking characteristics of new and used CSF shunt tubing catheters to determine if any inherent physical properties predispose the tubing to fracture.
Methods. Fifty-millimeter segments of new and retrieved (used) CSF shunt tubing were stretched to 120 mm in a hydraulic press to determine modulus values (modulus = stress/strain) and to measure permanent tubing deformation imparted by the applied stress and strain. Similar 50-mm tubing segments were also stretched in an electromechanical material testing system until fracture occurred; the force and strain needed to break the tubing was recorded at the time of failure. The results demonstrate that shunt tubing with a greater cross-sectional area requires greater force to fracture, and that catheters become weaker the longer they are implanted. Barium-impregnated shunt tubing, compared with translucent tubing, appears to require less applied stress and strain to break and may fracture more easily in vivo. The variety of modulus values obtained for the new catheters tested indicates that the various companies may be using materials of different quality in tubing manufacture.
Conclusions. A CSF shunt catheter design that incorporates tubing with a greater cross-sectional area may lead to fewer fractures of indwelling catheters and a reduction in shunt revision surgery.
Experimental appraisal of the lack of antitumor natural killer cell—mediated immunosurveillance in response to lymphomas growing in the mouse brain
Authors: Yamasaki Toshiki , Moritake Kouzo , Klein George 
Published: May 2009

Object. Natural killer (NK) cell—mediated immunosurveillance in the brain is currently obscure, in contrast with the intracerebral immune reaction of cytotoxic T lymphocytes (CTLs) to tumor cells. The goal of this study, in which a controlled tumor model was used, was to investigate a relationship between NK cells and major histocompatibility complex (MHC) Class I gene expression in intracerebral tumor—bearing hosts.
Methods. A matched set of two cloned tumor cell lines (lymphoma+ and lymphoma−), which differ only in MHC Class I gene expression, was established from the parental YAC-1 cell line (a target widely accepted as being sensitive to murine NK cells). An in vivo rapid elimination assay (REA) was performed using tumor cells labeled with [125I] 5-iodo-2-deoxyuridine to evaluate intracerebral NK cell—mediated defense immunity. There was no difference in the in vitro growth rate and c-myc gene expression between lymphoma+ and lymphoma− cells. An in vitro cytotoxicity assay showed that the lymphoma+ cell line was sensitive to MHC Class I—restricted CTL-mediated lysis, whereas the lymphoma− line was refractory to it. Both were susceptible to NK cell—mediated lysis, comparable to the level shown by YAC-1 cells. Flow cytometry revealed that lymphoma+ reacted positively for cell-surface MHC Class I molecules, whereas lymphoma− had no reaction. Four- to 72-hour REAs, performed using either cell line, disclosed no clearance of radiolabeled tumor cells from the brain in independent groups of untreated and T cell—depleted mice; this contrasted with eradication of radioactivity from the lungs. In NK cell—depleted mice, however, there was no elimination of radiolabeled tumor cells from the brain or lungs. The MHC Class I expression on lymphoma+ cells was enhanced after intracerebral inoculation, rendering them less sensitive to NK cells. By contrast, lymphoma− cells remained negative for cell-surface MHC expression, being sensitive to NK cells and refractory to CTLs after intracerebral inoculation. These results indicate the absence of NK cell—mediated lytic activity in the brain. This allows even NK cell—sensitive tumor cells to escape intracerebral immunosurveillance.
Conclusions. These experiments have refined the information that the brain may lack NK cell—mediated defense immunity against intracerebrally growing tumors, representing a characteristic aspect of this immunologically privileged organ.
Subclinoid aneurysms
Authors: Nutik Stephen L. 
Published: May 2009

Object. This study was undertaken to analyze the features that define subclinoid aneurysms.
Methods. Five cases of laterally directed carotid artery (CA) aneurysms adjacent to the anterior clinoid process (ACP) were identified in a series of approximately 1400 surgically treated aneurysms. These cases were selected because the aneurysms had the same features as the only previously described “subclinoid” aneurysm. The angiographic and anatomical features of the five cases were analyzed.
Conclusions. Subclinoid aneurysms are a unique group of congenital berry aneurysms. They originate from the lateral surface of the CA adjacent to the ACP. They are partially or completely hidden from view at surgery by the ACP and are partially or completely proximal to the distal dural ring of the CA. The proximal neck of these lesions is located at the same level of the CA cut perpendicular to its axis of blood flow as the origin of the ophthalmic artery (OphA), but they do not originate at that or any other branch of the CA. They can only be definitively differentiated from OphA, anterior paraclinoid, and blister-like aneurysms at surgery.
Long-term seizure outcomes following amygdalohippocampectomy
Authors: Wieser H. Gregor , Ortega Marcos , Friedman Alon , Yonekawa Yasuhiro 
Published: May 2009

Object. Analyses of the results of surgery for epilepsy are hindered by inconsistent classifications of seizure outcome, small numbers of patients, and short postoperative follow-up periods. The authors conducted a retrospective study with a reassessment of the long-term seizure outcomes in patients who underwent selective amygdalohippocampectomy (SelAH) for pharmacotherapy—resistant mesial temporal lobe epilepsy (MTLE) at the Zurich University Hospital from 1975 to 1999.
Methods. Year-by-year data and the last available data on seizure outcomes were retrospectively assessed for 369 consecutively surgically treated patients who had participated in a follow-up period longer than 1 year as of 1999 and whose outcomes were classified according to the Engel scale and the proposed new International League Against Epilepsy (ILAE) scale. Patients were grouped into nonlesional and lesional MTLE groups depending on whether they harbored a gross anatomical lesion that caused the MTLE. Differentiation was made between curative and palliative operations. Complications related to surgery are reported for 453 patients who underwent SelAH and participated in more than 3 months of follow-up review.
The last available outcome data according to the Engel scale were found to be generally similar to those of the new ILAE classification, with 66.9% of patients free from disabling seizures (Engel Class I) compared with 57.1% who were completely seizure and aura free (ILAE Class 1). The last available data on seizure outcome were not significantly different between patients in the lesional and nonlesional MTLE groups. In the lesional group, seizure outcomes were significantly better when patients underwent surgery early in the course of the disease. Overall, 70% of the patients received reductions in their antiepileptic drug treatment at the time of the last available follow-up review. Complications related to the surgical procedures were rare.
Conclusions. The authors conclude that SelAH is a safe and effective surgical procedure for MTLE.
Usefulness of intraoperative electrical subcortical mapping during surgery for low-grade gliomas located within eloquent brain regions: functional results in a consecutive series of 103 patients
Authors: Duffau Hugues , Capelle Laurent , Denvil Dominique , Sichez Nicole , Gatignol Peggy , Taillandier Luc , Lopes Manuel , Mitchell Mary-Christine , Roche Sabine , Muller Jean-Charles , Bitar Ahmad , Sichez Jean-Pierre , van Effenterre Rémy 
Published: May 2009

Object. Although a growing number of authors currently advocate surgery to treat low-grade gliomas, controversy still persists, especially because of the risk of inducing neurological sequelae when the tumor is located within eloquent brain areas. Many researchers performing preoperative neurofunctional imaging and intraoperative electrophysiological methods have recently reported on the usefulness of cortical functional mapping. Despite the frequent involvement of subcortical structures by these gliomas, very few investigators have specifically raised the subject of fiber tracking. The authors in this report describe the importance of mapping cortical and subcortical functional regions by using intraoperative realtime direct electrical stimulations during resection of low-grade gliomas.
Methods. Between 1996 and 2001, 103 patients harboring a corticosubcortical low-grade glioma in an eloquent area, with no or only mild deficit, had undergone surgery during which intraoperative electrical mapping of functional cortical sites and subcortical pathways was performed throughout the procedure.
Both eloquent cortical areas and corresponding white fibers were systematically detected and preserved, thus defining the resection boundaries. Despite an 80% rate of immediate postoperative neurological worsening, 94% of patients recovered their preoperative status within 3 months—10% even improved—and then returned to a normal socioprofessional life. Eighty percent of resections were classified as total or subtotal based on control magnetic resonance images.
Conclusions. The use of functional mapping of the white matter together with cortical mapping allowed the authors to optimize the benefit/risk ratio of surgery of low-grade glioma invading eloquent regions. Given that preoperative fiber tracking with the aid of neuroimaging is not yet validated, we used intraoperative real-time cortical and subcortical stimulations as a valuable adjunct to the other mapping methods.
Radiation exposure of normal temporal bone structures during stereotactically guided gamma knife surgery for vestibular schwannomas
Authors: Linskey Mark E. , Johnstone Peter A. S. , O'Leary Michael , Goetsch Steven 
Published: May 2009

Object. The dosimetry of radiation exposure of healthy inner, middle, and external ear structures that leads to hearing loss, tinnitus, facial weakness, dizziness, vertigo, and imbalance after gamma knife surgery (GKS) for vestibular schwannomas (VSs) is unknown. The authors quantified the dose of radiation received by these structures after GKS for VS to assess the likelihood that these doses contributed to postradiosurgery complications.
Methods. A retrospective study was performed using a prospectively acquired database of a consecutive series of 54 patients with VS who were treated with GKS during a 3.5-year period at an “open unit” gamma knife center. Point doses were measured for 18 healthy temporal bone structures in each patient, with the anatomical position of each sampling point confirmed by a fellowship-trained neurootologist. These values were compared against single-dose equivalents for the 5-year tolerance dose for a 5% risk of complications and the 5-year tolerance dose for a 50% risk of complications, which were calculated using known 2-Gy/fraction thresholds for chronic otitis, chondromalacia, and osseous necrosis, as well as the tumor margin dose and typical tumor margin prescription doses for patients in whom hearing preservation was attempted.
External and middle ear doses were uniformly low. The intratemporal facial nerve is susceptible to unintentionally high radiation exposure at the fundus of the internal auditory canal, with higher than tumor margin doses detected in 26% of cases. In the cochlea, the basal turn near the modiolus and its inferior portion are most susceptible, with doses greater than 12 Gy detected in 10.8 and 14.8% of cases. In the vestibular labyrinth, the ampulated ends of the lateral and posterior semicircular canals are most susceptible, with doses greater than 12 Gy detected in 7.4 and 5.1% of cases.
Conclusions. Doses delivered to middle and external ear structures are unlikely to contribute to post-GKS complications, but unexpectedly high doses may be delivered to sensitive areas of the intratemporal facial nerve and inner ear. Unintentional delivery of high doses to the stria vascularis, the sensory neuroepithelium of the inner ear organs and/or their ganglia, may play a role in the development of post-GKS tinnitus, hearing loss, dizziness, vertigo, and imbalance. Minimizing treatment complications post-GKS for VS requires precise dose planning conformality with the three-dimensional surface of the tumor.
Multislice computerized tomography angiography in the evaluation of intracranial aneurysms: a comparison with intraarterial digital subtraction angiography
Authors: Wintermark Max , Uske Antoine , Chalaron Marc , Regli Luca , Maeder Philippe , Meuli Reto , Schnyder Pierre , Binaghi Stefano 
Published: May 2009

Object. The goal of this study was to assess the diagnostic accuracy of computerized tomography (CT) angiography performed with the aid of multislice technology (MSCT angiography) in the investigation of intracranial aneurysms, by comparing this method with intraarterial digital subtraction (IADS) angiography.
Methods. Fifty consecutive adult patients, who successively underwent MSCT angiography (four rows) and IADS angiography of intracranial vessels, were prospectively identified. The MSCT angiography studies consisted of 1.25-mm slices, with 0.8-mm reconstruction intervals, a pitch of 0.75, and timing determined by a test bolus. Two neuroradiologists, who were blinded to the initial interpretation of the MSCT angiograms as well as to those of the IADS angiograms, independently reviewed the MSCT angiograms for the detection and characterization of intracranial aneurysms.
Forty-nine intracranial aneurysms were identified in 40 patients; 33 of these lesions were responsible for subarachnoid hemorrhage. The sensitivity, specificity, and accuracy of MSCT angiography in the detection of intracranial aneurysms were 94.8, 95.2, and 94.9%, respectively, on a per-aneurysm basis and 99, 95.2, and 98.3%, respectively, on a per-patient basis. Interobserver agreement was 98%. There was an excellent correlation between aneurysm size assessed using MSCT angiography and that determined by IADS angiography (slope = 0.916, r = 0.877, p < 0.001); however, 2 mm stood as the cutoff size below which the sensitivity of MSCT angiography was statistically lower. That method displayed great accuracy in characterizing the morphological characteristics of the aneurysm.
Conclusions. Multislice CT angiography is an accurate and robust noninvasive screening test for intracranial aneurysms. It performs better than that reported for single-slice CT angiography. Introduction of eight- and especially 16-row MSCT angiography will provide further progression through thinner slices, a lower pitch, and a purely arterial phase.