bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scanning electron microscopy of the floor of the fourth ventricle in rats subjected to graded impact injury to the sensorimotor cortex
Authors: Sarphie Theodore G. , Carey Michael E. , Davidson June F. , Soblosky Joseph S. 
Published: May 2009

Object. Respiratory dysfunction including apnea frequently follows head injury in humans. The purpose of this study was to identify any structural alterations in the region of brainstem respiratory nuclei that might account for immediate postinjury respiratory abnormalities in anesthetized experimental animals.Methods. Using scanning electron microscopy, the authors examined the floor of the fourth ventricle in injured rats after a piston strike to the sensorimotor cortex that depressed the dura 1, 2, or 4 mm. The rats were killed within minutes of injury. Cortical impact depths measuring either 1 or 2 mm (eight rats) produced no respiratory abnormalities, and the structural integrity of the ependymal lining of the ventricular floor in these animals was not compromised. Thirteen rats were subjected to impact to a 4-mm depth and 10 of these exhibited immediate temporary or permanent apnea. The medullae of nine of these rats were studied using scanning electron microscopy, and the fourth ventricular floors of all nine rats showed tears. Four rats that exhibited immediate, permanent apnea had tears in the caudal fourth ventricle floor near the obex, whereas five rats with no or only transient apnea had tears located more anteriorly, near the aqueduct or laterally. Changes in cerebrospinal fluid flow or pressure dynamics may have caused these tears. Light microscopy, focused near the area postrema, revealed a shearing defect through the ependyma of the fourth ventricular floor into the subjacent neuropil with a disruption of axonal pathways.Conclusions. Respiratory neuronal network components lying within 2 mm of the area postrema may well have been disrupted by the caudal tears producing permanent apnea. A similar phenomenon could account for the transient or permanent postinjury apnea seen in humans with severe head injury.
Vascular components of cerebrospinal fluid compensation
Authors: Czosnyka Marek , Richards Hugh K. , Czosnyka Zofia , Piechnik Stefan , Pickard John D. 
Published: May 2009

Object. The aim of the study was to assess how cerebrospinal fluid (CSF) pressure—volume compensation depends on cerebrovascular tone.Methods. In 26 New Zealand White rabbits, intracranial pressure (ICP), arterial blood pressure, and basilar artery blood flow velocity were measured continuously. Saline was infused into the cranial subarachnoid space to assess CSF compensatory parameters: the resistance to CSF outflow, the elastance coefficient, and the amplitude of the ICP pulsatile waveform. Infusions were repeated on two different levels of CO2 concentration in the arterial blood (PaCO2), at normotension and hypotension, and after the death of the animal.An increase in PaCO2 from a mean of 27 to 48 mm Hg was accompanied by an 18% increase in the resistance to CSF outflow (p < 0.005) and a 64% increase (p < 0.05) in the elastance coefficient. A decrease in arterial blood pressure from a mean of 100 to 51 mm Hg caused a 25% decrease in CSF outflow resistance (p < 0.01) but did not affect the elastance coefficient. Postmortem, a 23% decrease in the CSF outflow resistance was associated with a 102% decrease in the elastance coefficient.Conclusions. Cerebrovascular parameters have a limited but significant impact on CSF infusion studies. The vascular component of ICP may be identified as a significant factor contributing to this phenomenon. During infusion studies, physiological parameters influencing vascular conditions should be maintained as stable as possible.
Computer-generated surgical simulation of morphological changes in microstructures: concepts of “virtual retractor”
Authors: Koyama Toru , Okudera Hiroshi , Kobayashi Shigeaki 
Published: May 2009

✓ The authors' goal was to develop a computer graphics model to simulate the displacement and morphological changes that are caused by the retraction of fine intracranial structures.The authors developed an application program to interpolate the contour of models of an artery and a retractor. The center of the displacement was determined by spatial coordinates, and the shape of the displacement of the arterial model was calculated using a cosine-based formula with representation of a brain retractor. This computer graphics model was applied to the simulation of the displacement and morphological changes that occur when retraction is performed in the optic nerve. An illustrative case is presented, in which the optic nerve was displaced by a retractor to simulate the surgery performed in a carotid cave aneurysm of the internal carotid artery.The authors have named this methodological tool a “virtual retractor.” This new navigational system for open microneurosurgery would be useful in teaching surgical microanatomy and in presurgical operative planning.
Long-term patency of radial artery graft bypass for reconstruction of the internal carotid artery
Authors: Houkin Kiyohiro , Kamiyama Hiroyasu , Kuroda Satoshi , Ishikawa Tatsuya , Takahashi Akihiro , Abe Hiroshi 
Published: May 2009

✓ Reconstruction of the carotid artery by using a radial artery graft is a useful option that can produce reliable long-term patency for the surgical treatment of giant and/or large aneurysms of the cavernous and paraclinoid internal carotid artery (ICA).During the past 10 years, 43 patients with intracavernous and paraclinoid giant aneurysms of the ICA have been treated by reconstruction of the ICA with radial artery grafts after ligation of the cervical ICA. The long-term patency of the grafted radial artery was evaluated over more than a 5-year period (mean 7.2 years) in 20 of these patients by using magnetic resonance angiography or conventional angiography. There was no late occlusion of the graft in any of these cases. Stenotic graft changes were observed in two cases.
Stereotactic radiosurgery in the management of acoustic neuromas associated with neurofibromatosis Type 2
Authors: Subach Brian R. , Kondziolka Douglas , Lunsford L. Dade , Bissonette David J. , Flickinger John C. , Maitz Ann H. 
Published: May 2009

Object. Stereotactically guided radiosurgery is one of the primary treatment modalities for patients with acoustic neuromas (vestibular schwannomas). The goal of radiosurgery is to arrest tumor growth while preserving neurological function. Patients with acoustic neuromas associated with neurofibromatosis Type 2 (NF2) represent a special challenge because of the risk of complete deafness. To define better the tumor control rate and long-term functional outcome, the authors reviewed their 10-year experience in treating these lesions.Methods. Forty patients underwent stereotactic radiosurgery at the University of Pittsburgh, 35 of them for solitary tumors. The other five underwent staged procedures for bilateral lesions (10 tumors, 45 total). Thirteen patients (with 29% of tumors) had undergone a median of two prior resections. The mean tumor volume at radiosurgery was 4.8 ml, and the mean tumor margin dose was 15 Gy (range 12–20 Gy).The overall tumor control rate was 98%. During the median follow-up period of 36 months, 16 tumors (36%) regressed, 28 (62%) remained unchanged, and one (2%) grew. In the 10 patients for whom more than 5 years of clinical and neuroimaging follow-up results were available (median 92 months), five tumors were smaller and five remained unchanged. Surgical resection was performed in three patients (7%) after radiosurgery; only one showed radiographic evidence of progression. Useful hearing (Gardner—Robertson Class I or II) was preserved in six (43%) of 14 patients, and this rate improved to 67% after modifications made in 1992. Normal facial nerve function (House—Brackmann Grade 1) was preserved in 25 (81%) of 31 patients. Normal trigeminal nerve function was preserved in 34 (94%) of 36 patients.Conclusions. Stereotactically guided radiosurgery is a safe and effective treatment for patients with acoustic tumors in the setting of NF2. The rate of hearing preservation may be better with radiosurgery than with other available techniques.
Radiotherapy in the treatment of benign meningioma of the skull base
Authors: Nutting Christopher , Brada Michael , Brazil Lucy , Sibtain Ahmen , Saran Frank , Westbury Charlotte , Moore Anne , Thomas David G. T. , Traish Daphne , Ashley Susan 
Published: May 2009

Object. This study was undertaken to assess the long-term efficacy and toxicity of conventional fractionated external-beam radiation in the treatment of benign skull base meningioma.Methods. This is a retrospective study of 82 patients with histologically verified benign skull base meningioma treated by surgery followed by fractionated external-beam radiation at the Royal Marsden Hospital between 1962 and 1992. The 5- and 10-year progression-free survival (PFS) rates were 92% and 83%, respectively, with the site of disease being the only independent prognostic factor for tumor control according to multivariate analysis. The 10-year PFS rate for patients with sphenoid ridge meningiomas was 69% compared with 90% for those with tumors in the parasellar region. The overall 10-year survival rate was 71%, with performance status and patient age found to be significant independent prognostic factors. Six patients had worsening vision, which was due to cataract in five cases and retinopathy in one. There were no recorded cases of cranial nerve neuropathy.Conclusions. The excellent long-term tumor control and length of survival with minimal toxicity associated with conventional external-beam radiation should serve as a baseline for evaluation of new treatment strategies such as radiosurgery and skull base surgery.
Treatment of basilar artery bifurcation aneurysms by using Guglielmi detachable coils: a 6-year experience
Authors: Bavinzski Gerhard , Killer Monika , Gruber Andreas , Reinprecht Andrea , Gross Cordell E. , Richling Bernd 
Published: May 2009

Object. The authors retrospectively analyzed the results of their 6-year experience in the treatment of basilar artery (BA) bifurcation aneurysms by using Guglielmi detachable coils (GDCs).Methods. This analysis involved 45 BA tip aneurysms in 16 men and 29 women who ranged in age from 23 to 78 years (mean 50 years). Seventy-five percent of the aneurysms had ruptured and 25% remained unruptured. Of the group whose aneurysms hemorrhaged, 14 patients were Hunt and Hess Grade I or II and 20 were Hunt and Hess Grades III to V; 32 patients were treated within 2 weeks of their subarachnoid hemorrhage (SAH). Initially, treatment with GDCs was limited to poor-grade high-risk patients who refused surgery or patients in whom surgery proved unsuccessful. Later in the study, good-grade patients with narrow-necked aneurysms were also treated using GDCs.The length of clinical follow up ranged from 1 to 72 months (average 27.4 months) in the 37 surviving patients. In 33 of the 45 aneurysms treated with coil placement, good to excellent results were achieved. There were 12 poor results (27%) including one in a patient from the non-SAH group who suffered a thrombotic complication due to an underlying vasculitis. Eight deaths were recorded in this group of 45 patients. One of these deaths was caused by a complication related to anesthesia, one by unknown causes, and six resulted from complications of the disease. One patient rebled on the 2nd day after the endovascular procedure. The mortality and permanent morbidity rates directly related to the intervention were 2.2% and 4.4%, respectively.Angiographic studies obtained immediately postintervention demonstrated 99 to 100% occlusion in 30 (67%) of the aneurysms; nine (20%) were more than 90% occluded; and six (13%) were less than 90% occluded by the GDCs. Follow-up angiograms were obtained in 31 patients between 2 and 72 months after coil placement. Nineteen (61%) of the follow-up angiograms revealed stable results (that is, no change from initial treatment). Twelve of the 31 showed coil compaction, but only eight of these lesions could accept additional coils.In large aneurysms recanalization was seen in 57%, and some of the larger lesions required as many as four embolizations (mean 1.7) to achieve optimal occlusion. When small-necked aneurysms were analyzed as a subset, a stable angiographic result was seen in 92%.Conclusions. Use of GDCs led to excellent clinical and angiographic results in the majority of patients with BA tip aneurysms included in this limited follow-up study. Rebleeding was encountered in one of the 34 previously ruptured BA aneurysms treated with GDCs, and no hemorrhages have been documented in the 11 unruptured aneurysms treated with GDCs in this series. Long-term follow-up studies are necessary before it is possible to compare adequately the treatment of aneurysms with coil placement to the gold standard of aneurysm clipping.
Prevalence of cerebral aneurysms in patients with persistent primitive trigeminal artery
Authors: Cloft Harry J. , Razack Nasser , Kallmes David F. 
Published: May 2009

Object. The aim of this study was to determine the prevalence of cerebral saccular aneurysms in patients with persistent primitive trigeminal artery (PPTA). The prevalence of cerebral saccular aneurysms in patients with PPTA previously has been reported to be 14 to 32%, but this rate range is unreliable because it is based on collections of published case reports rather than a series of patients chosen in an unbiased manner.Methods. The authors retrospectively evaluated their own series of 34 patients with PPTA to determine the prevalence of cerebral aneurysms in this population. The prevalence of intracranial aneurysms in patients with PPTA was approximately 3% (95% confidence interval 0–9%).Conclusions. The prevalence of intracranial aneurysms in patients with PPTA is no greater than the prevalence of intracranial aneurysms in the general population.
Effects of clotrimazole on the growth, morphological characteristics, and cisplatin sensitivity of human glioblastoma cells in vitro
Authors: Khalid M. Humayun , Shibata Shobu , Hiura Tsuyoshi 
Published: May 2009

Object. Clotrimazole, an antimycotic drug, inhibits proliferation of normal and cancer cells by downregulating the movement of intracellular Ca++ and K+. The authors examined the effect of clotrimazole on the growth and sensitivity to cisplatin of two human glioblastoma cell lines—A172, which has the wild-type p53 gene, and T98G, which has the mutant p53 gene in vitro.Methods. The A172 and T98G glioblastoma cells were exposed to clotrimazole and cell growth was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium chloride colorimetric assay. Clotrimazole produced a dose-dependent inhibition of cell proliferation and caused changes in cellular structure toward a well-differentiated form. The growth inhibitory effect of clotrimazole was reversible. Western immunoblot analysis revealed a marked increase in cellular glial fibrillary acidic protein and wild-type p53 and a decrease in c-myc and c-fos oncoproteins in both cell lines treated with clotrimazole. Flow cytometric analysis revealed that clotrimazole-treated cells accumulated in the G0/G1 phase with a marked decrease in cells in the S phase; when clotrimazole was washed out from the culture medium, cells again started to proliferate, with a marked decrease in cells in the G0/G1 phase and an increase in cells in the S phase. The growth inhibitory effect of clotrimazole could not be overcome by exogenous stimulation with either epidermal growth factor or c-myc peptide. A combined treatment with clotrimazole and cisplatin significantly enhanced cell cytotoxicity compared with treatment using either drug alone. A DNA fragmentation assay showed that both clotrimazole and cisplatin induced apoptosis, which was increased in cells treated by both drugs.Conclusions. The present study indicates that clotrimazole inhibits cell proliferation accompanied by morphological changes toward differentiation of glioblastoma cells and that this drug synergistically enhances the antitumor effect of cisplatin by inducing wild-type p53—mediated apoptosis.
Reversal of experimental parkinsonism by using selective chemical ablation of the medial globus pallidus
Authors: Lieberman Daniel M. , Corthesy Marc-Etienne , Cummins Alex , Oldfield Edward H. 
Published: May 2009

Object. Symptoms from Parkinson's disease improve after surgical ablation of the medial globus pallidus (GPm). Although, in theory, selective chemical ablation of neurons in the GPm could preserve vital structures jeopardized by surgery, the potential of this approach is limited when using traditional techniques of drug delivery. The authors examined the feasibility of convection-enhanced distribution of a neurotoxin by high-flow microinfusion to ablate the neurons of the GPm selectively and reverse experimental Parkinson's disease (akinesia, tremor, and rigidity).Methods. Initially, to test the feasibility of this approach, the GPms of two naive rhesus macaques were infused with kainic acid or ibotenic acid through two cannulas that had been placed using the magnetic resonance imaging—guided stereotactic technique. Two weeks later the animals were killed and their brains were examined histologically to determine the presence of neurons in the GPm and the integrity of the optic tract and the internal capsule. To examine the therapeutic potential of this paradigm, unilateral experimental Parkinson's disease was induced in six macaques by intracarotid infusion of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and their behavior was studied for 12 weeks after chemopallidotomy was performed using kainic acid (three animals) or control infusion (three animals).Conclusions. Chemopallidotomy using kainic acid permanently reversed the stigmata of MPTP-induced parkinsonism. By contrast, the control animals exhibited a transient recovery following intrapallidal infusion and then relapsed back to their baseline state. The use of high-flow microinfusion of selectively active toxins has the potential for treatment of Parkinson's disease and, by expanding the range of approachable targets to include large nuclei, for broad applications in clinical and experimental neuroscience.
Neural network analysis of preoperative variables and outcome in epilepsy surgery
Authors: Arle Jeffrey E. , Perrine Kenneth , Devinsky Orrin , Doyle Werner K. 
Published: May 2009

Object. Because appropriate patient selection is essential for achieving successful outcomes after epilepsy surgery, the need for more robust methods of predicting postoperative seizure control has been created. Standard multivariate techniques have been only 75 to 80% accurate in this regard. Recent use of artificial intelligence techniques, including neural networks, for analyzing multivariate clinical data has been successful in predicting medical outcome.Methods. The authors applied neural network techniques to 80 consecutive patients undergoing epilepsy surgery in whom data on demographic, seizure, operative, and clinical variables to predict postoperative seizures were collected.Neural networks could be used to predict postoperative seizures in up to 98% of cases. Student's t-tests or chi-square analysis performed on individual variables revealed that only the preoperative medication index was significantly different (p = 0.02) between the two outcome groups. Six different combinations of input variables were used to train the networks. Neural network accuracies differed in their ability to predict seizures: using all data (96%); all data minus electroencephalography concordance and operative side (93%); all data except intra- or postoperative variables such as tissue pathological category (98%); all data excluding pathological category, intelligence quotient (IQ) data, and Wada results (84%); only demographics and tissue pathological category (65%); and only IQ data (63%).Conclusions. Analysis of the results reveals that several networks that are trained with the usual accepted variables characterizing the typical evaluation of epilepsy patients can predict postoperative seizures with greater than 95% accuracy.
Double-blind, randomized, vehicle-controlled study of high-dose tirilazad mesylate in women with aneurysmal subarachnoid hemorrhage. Part II. A cooperative study in North America
Authors: Lanzino Giuseppe , Kassell Neal F. , _ _ 
Published: May 2009

Object. To test the safety and efficacy of high-dose (15 mg/kg/day) tirilazad mesylate in women suffering from aneurysmal subarachnoid hemorrhage (SAH), a prospective randomized, double-blind, vehicle-controlled trial (parallel to the one conducted in Europe, Australia, New Zealand, and South Africa) was performed at 65 North American neurosurgical centers.Methods. Of the 832 patients who were randomized, 823 received at least one dose of tirilazad (410 patients) or placebo vehicle containing citrate (413 patients). The two groups were similar with respect to their prognostic factors for overall outcome and delayed cerebral ischemia. There were no differences in medical and surgical interventions including hyperdynamic therapy (intentional hypervolemia, induced hypertension, and/or hemodilution) between the two treatment groups.In contrast to the accompanying study, the protocol for the North American study was formally amended, in that a sequential analysis of the primary efficacy end point, mortality rate at 91 days postdosing, was performed. This analysis revealed a statistically significant difference in mortality rates, favoring the study drug, among patients who were neurological Grade IV or V at admission (24.6% compared with 43.4% in the placebo-treated group, p = 0.016). No significant differences, however, were found when the entire patient population was considered (15.6% in the placebo-treated group and 13% in the tirilazad-treated group). Other major and secondary end points, which included rate of favorable outcome (74% in the placebo-treated group and 71% in the tirilazad-treated group); symptomatic vasospasm (38% in the placebo-treated group and 35% in the tirilazad-treated group); and vasospasm severity (severe symptomatic vasospasm in 14% of patients in both groups), were also not significantly different between the two groups. In patients with neurological Grades I through III, rates of favorable outcome advantageous to the vehicle-treated group were observed (83.3% compared with 76.7%, p = 0.04).Conclusions. High-dose tirilazad mesylate is well tolerated in women with aneurysmal SAH. Sequential analysis revealed a significant reduction in mortality rates among patients with neurological Grades IV and V, favoring the study drug and confirming the same effect observed in male patients in previous large studies. No beneficial effect was observed in patients who were in a good neurological grade at admission.