bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of potassium channel inhibitors on the relaxation induced by the NO donor DEA/NO in isolated human cerebral arteries
Authors: Hempelmann Ralf G. , Seebeck Jörg , Ziegler Albrecht , Mehdorn H. Maximilian
Published: May 2009

Object. The goal of this study was to investigate whether K+ channels are involved in nitric oxide (NO)—induced relaxation of isolated human cerebral arteries.

Methods. Successive concentration—response curves relating to the use of the NO donor diethylamine NO (DEA/NO) were established in the absence and presence of different K+ channel inhibitors after mounting human cerebral arteries onto a wire myograph. The arteries were obtained from macroscopically intact tissue that had been removed during brain tumor operations.

A high K+ concentration partially inhibited the relaxant effects of DEA/NO. Different K+ channel inhibitors (tetraethylammonium [TEA], 10−3 M; charybdotoxin, 10−7 M; glibenclamide, 10−6 M; 4-aminopyridine [4-AP], 10−3 M; BaCl2, 5 × 10−5 M; and apamin, 10−6 M) alone failed to affect the responses to DEA/NO. However, a combination of TEA, glibenclamide, 4-AP, and BaCl2 partially blocked the relaxant effects of DEA/NO. In addition, the effects of DEA/NO were inhibited by the thromboxane A2 analog U46619 (3 × 10−7 M).

Conclusions. Inhibitors of the large-conductance or small-conductance Ca++-activated K+ channels, the adenosine triphosphate— sensitive K+ channels, and the delayed-rectifier or inward-rectifier K+ channels failed to alter the effects of DEA/NO when only one K+ channel blocker was used. However, a regimen of a combination of K+ channel blockers that possess selectivity for different channels demonstrated that different K+ channel types are involved; these channels may function in a redundant manner and compensate for each other. Selective thromboxane A2 agonists are capable of inhibiting the relaxant response to the NO donor.
Angiographic progression in adult moyamoya disease
Authors: Tomida Mamoru , Muraki Masaaki , Yamasaki Kenji
Published: May 2009

✓ The authors present the case of a 37-year-old man with definite moyamoya disease in whom angiographic findings drastically changed. The patient presented with left hemiparesis due to lacunar infarction. Angiography initially disclosed a narrow right carotid artery (CA) siphon and severe stenosis of the horizontal segment of the left middle cerebral artery. Four years later, the patient experienced right-central facial paresis, which developed because of a small putaminal hematoma. Angiography results demonstrated occlusion of the internal CA siphons bilaterally, with moyamoya vessels. It therefore appears that in some adults, moyamoya disease is accompanied by very progressive vascular changes.
Linear accelerator radiosurgery for vestibular schwannoma
Authors: Spiegelmann Roberto , Lidar Zvi , Gofman Jana , Alezra Dror , Hadani Moshe , Pfeffer Raphael
Published: May 2009

Object. The use of radiosurgery in the treatment of acoustic neuromas has increased substantially during the last decade. Most published experience relates to the use of the gamma knife. In this report, the authors review the methods and results of linear accelerator (LINAC) radiosurgery in 44 patients with acoustic neuromas who were treated between 1993 and 1997.

Methods. Computerized tomography scanning was selected as the stereotactic imaging modality for target definition. A single, conformally shaped isocenter was used in the treatment of 40 patients; two or three isocenters were used in four patients who harbored very irregular tumors. The radiation dose directed to the tumor border was the only parameter that changed during the study period: in the first 24 patients who were treated the dose was 15 to 20 Gy, whereas in the last 20 patients the dose was reduced to 11 to 14 Gy. After a mean follow-up period of 32 months (range 12–60 months), 98% of the tumors were controlled. The actuarial hearing preservation rate was 71%. New transient facial neuropathy developed in 24% of the patients and persisted to a mild degree in 8%. Radiation dose correlated significantly with the incidence of cranial neuropathy, particularly in large tumors (≥ 4 cm3).

Conclusions. Single-isocenter LINAC radiosurgery proved to be an effective treatment for acoustic neuromas in this series, with results that were comparable with those reported for gamma knife radiosurgery and multiple isocenters.
Surgical treatment for neocortical temporal lobe epilepsy: clinical and surgical aspects and seizure outcome
Authors: Schramm Johannes , Kral Thomas , Grunwald Thomas , Blümcke Ingmar
Published: May 2009

Object. The goal of this paper was to describe the clinical and surgical aspects of a group of patients suffering from drug-resistant neocortical temporal lobe epilepsy (TLE), as well as seizure outcomes and factors affecting seizure outcomes in these patients.

Methods. This study was based on data prospectively collected and retrospectively evaluated. Sixty-two patients with neocortical TLE constituted the study population. Only patients who underwent corticectomies, lesionectomies, lateral anterior lobe resections, and/or multiple subpial transections were included. The pathological areas resected in these patients could be separated into three groups composed of 35 neoplastic lesions, 23 nonneoplastic lesions, and three nonlesional areas. The mean duration of follow-up review in these patients was 21.9 ± 14 months.

Outcomes were categorized according to Engel classes. Class I was found in 79% of the patients and Class II in 11%. Invasive presurgical evaluation was performed in 43% of the patients. There were only temporary complications (3.3% surgical and 1.6% neurological) and no deaths. In summary, lesions confirmed on histological examination were rarely found in patients with neocortical TLE. Low-grade tumors were the most commonly found lesions in these patients and the most common tumor was ganglioglioma. Outcome was best for those patients with neoplastic lesions and was independent of the duration of their seizures. Outcome was little influenced by the type of resection performed and was found to be as good as that achieved in patients with mesial TLE.

Conclusions. These results demonstrate that the concept of lateral or neocortical TLE as a distinct entity is useful. Surgery for neocortical TLE can be considered a viable treatment option that is associated with a low morbidity rate and good outcomes.
Analysis of the results obtained in 120 patients with large acoustic neuromas surgically treated via the translabyrinthine—transtentorial approach
Authors: Sluyter Steven , Graamans Kees , Tulleken Cornelis A. F. , Van Veelen Cornelis W. M.
Published: May 2009

Object. The authors review the results of a series of 120 acoustic neuromas that were surgically treated via the translabyrinthine-transtentorial approach between 1986 and 1999.

Methods. The authors retrospectively evaluated a series of 120 acoustic neuromas with extrameatal diameters of 2 cm or greater, 99 (82.5%) of which had diameters longer than 3 cm. Complete tumor removal, as ascertained using computerized tomography or magnetic resonance imaging, was achieved in 110 patients (91.7%). The facial nerve was anatomically preserved in 97 patients (80.8%). The main postoperative complications were cerebrospinal fluid (CSF) leakage through the scalp wound (13.3%) requiring surgical revision in 2.5%, meningitis (9.2%), CSF rhinorrhea (6.7%) requiring surgical revision in 2.5%, and epileptic seizures (the only permanent complication) requiring medication (3.3%). There was no death directly related to the surgery. Long-term follow-up examination of the facial nerve revealed recovery of function to the level of House—Brackmann Grade I or II in 56.2% of the patients.

Conclusions. The results and complications presented in this series are comparable to those reported in the literature. The authors conclude that the combined translabyrinthine—transtentorial approach is a safe route for removing acoustic neuromas with a diameter of 2 cm or greater.
Frameless neuronavigation in intracranial endoscopic neurosurgery
Authors: Schroeder Henry W. S. , Wagner Wolfgang , Tschiltschke Wolfgang , Gaab Michael R.
Published: May 2009

Object. Frameless computerized neuronavigation has been increasingly used in intracranial endoscopic neurosurgery. However, clear indications for the application of neuronavigation in neuroendoscopy have not yet been defined. The purpose of this study was to determine in which intracranial neuroendoscopic procedures frameless neuronavigation is necessary and really beneficial compared with a free-hand endoscopic approach.

Methods. A frameless infrared-based computerized neuronavigation system was used in 44 patients who underwent intracranial endoscopic procedures, including 13 third ventriculostomies, nine aqueductoplasties, eight intraventricular tumor biopsy procedures or resections, six cystocisternostomies in arachnoid cysts, five colloid cyst removals, four septostomies in multiloculated hydrocephalus, four cystoventriculostomies in intraparenchymal cysts, two aqueductal stent placements, and fenestration of one pineal cyst and one cavum veli interpositi. All interventions were successfully accomplished. In all procedures, the navigational system guided the surgeons precisely to the target. Navigational tracking was helpful in entering small ventricles, in approaching the posterior third ventricle when the foramen of Monro was narrow, and in selecting the best approach to colloid cysts. Neuronavigation was essential in some cystic lesions lacking clear landmarks, such as intraparenchymal cysts or multiloculated hydrocephalus. Neuronavigation was not necessary in standard third ventriculostomies, tumor biopsy procedures, and large sylvian arachnoid cysts, or for approaching the posterior third ventricle when the foramen of Monro was enlarged.

Conclusions. Frameless neuronavigation has proven to be accurate, reliable, and extremely useful in selected intracranial neuroendoscopic procedures. Image-guided neuroendoscopy improved the accuracy of the endoscopic approach and minimized brain trauma.
Interleukin-6 overexpression as a marker of malignancy in human gliomas
Authors: Rolhion Christine , Penault-Llorca Frédérique , Kémény Jean-Louis , Lemaire Jean-Jacques , Jullien Christiane , Labit-Bouvier Corinne , Finat-Duclos Françoise , Verrelle Pierre
Published: May 2009

Object. Glioblastomas multiforme (GBMs) grow rapidly and are highly resistant to treatment compared with other glioma types and grades. Consequently, it is of major interest to identify markers of aggressiveness in these tumors that could represent new therapeutic targets. Interleukin (IL)—6 is frequently produced in gliomas and, given its manifold properties, could be considered as a candidate marker. Expression of IL-6 may be involved in cell growth, resistance to chemotherapy and radiotherapy (via an antiapoptotic pathway), and angiogenesis. This study was conducted to test this hypotheses and to evaluate the suitability of IL-6 as a target in the treatment of GBMs.

Methods. The authors studied the relationship between the level of IL-6 gene expression as assessed using semiquantitative reverse transcription—polymerase chain reaction and by determining various histological types and grades in a series of 59 gliomas. It was found that GBMs displayed a significantly higher level of IL-6 expression than other types of glioma (p < 0.001). Immunohistochemical analysis revealed that IL-6 was produced mainly by malignant cells and a few vascular endothelial cells.

Conclusions. It can be inferred from these findings that IL-6 gene expression is related to glioma aggressiveness and that IL-6 may play a central role in GBM behavior. Interleukin-6, therefore, could be considered as a new potential target in the treatment of GBMs.
Differential response of sensory and motor axons in nerve allografts after withdrawal of immunosuppressive therapy
Authors: Midha Rajiv , Nag Shudeshna , Munro Catherine A. , Ang Lee C.
Published: May 2009

Object. Rejection of nerve allografts and loss of regenerated host axons after withdrawal of immunosuppressive therapy poses an ongoing challenge in peripheral nerve repair. The present report is of a blinded prospective controlled study in which an established rat model of nerve allotransplantation is used to examine the effect of fiber type on survival and degeneration of nerve allografts after discontinuation of immunosuppression. The authors hypothesized that sensory axons will selectively resist a rejection response, whereas motor axons will degenerate.

Methods. Four-centimeter nerve segments from ACI rats were grafted into peroneal and sural (mixed) or saphenous (sensory) nerve gaps in Lewis rats. In some rats, L4–6 dorsal root ganglia were ablated before grafting, creating pure motor sural and peroneal nerves. All rats received 12 weeks of immunosuppressive therapy to support nerve regeneration into allografts. Immunosuppression with cyclosporin was then withdrawn. At planned death (12–18 weeks postsurgery), graft tissue was subjected to histomorphometric analysis for evaluation of axon survival and loss.

Graft rejection led to loss of all axons in approximately 60% of the allograft segments. The mixed nerve group was most prone to complete rejection, with significantly lowered axon counts at Weeks 16 and 18 compared with the Week 12 baseline. Axons from the sensory nerve were least likely to degenerate. The pure motor nerve group axons demonstrated intermediate sensitivity, with a selective loss of larger axons at Week 16 and a significant decrease in axon counts from the Week 12 baseline at Week 18.

Conclusions. Whereas the majority of axons are lost after withdrawal of immunosuppressive therapy from nerve allografts, there is a selective survival of axons from cutaneous sensory nerves and smaller-diameter motor fibers. The biological and molecular mechanisms that make some axons impervious to injury remain to be determined.
Molecular alterations in the neurofibromatosis Type 2 gene and its protein rarely occurring in meningothelial meningiomas
Authors: Evans James J. , Jeun Sin-Soo , Lee Joung H. , Harwalkar Jyoti A. , Shoshan Yigal , Cowell John K. , Golubic Mladen
Published: May 2009

Object. The neurofibromatosis Type 2 (NF2) gene is the only tumor suppressor gene that has been clearly implicated in the development of benign meningiomas. Interestingly, previous data obtained by the authors indicate that reduced NF2 protein expression seldom occurs in meningothelial meningiomas, the most common histological type of meningioma. The goal of the current study was to explore further the hypothesis of NF2 gene-independent tumorigenesis of meningothelial meningiomas.

Methods. The authors performed a mutational analysis of all 17 exons of the NF2 gene by using single-stranded conformational polymorphism (SSCP). In addition, expression levels of the NF2 protein and (µ-calpain, a protease suggested to inactivate the NF2 protein, were determined by immunoblotting analysis of 27 meningiomas (20 meningothelial and seven nonmeningothelial). Mutations of the NF2 gene were found in only one (5%) of 20 meningothelial meningiomas and three (43%) of seven nonmeningothelial tumors (Fisher's exact test, p = 0.042). The levels of NF2 protein were severely reduced in six (28.5%) of 21 meningothelial meningiomas, in contrast to six (86%) of seven nonmeningothelial meningiomas (Fisher's exact test, p = 0.023). Activation of (µ-calpain did not correlate with the status of NF2 protein expression in the meningiomas analyzed, demonstrating that (µ-calpain activation does not account for the loss of NF2 protein in meningiomas with apparently normal NF2 genes.

Conclusions. These results clearly demonstrate that NF2 gene mutations and decreased NF2 protein expression rarely occur in meningothelial meningiomas compared with other histological types of meningiomas. The clinical behavior of meningothelial meningiomas, however, is similar to that of other benign meningiomas. It is likely, therefore, that the tumorigenesis of meningothelial meningiomas is the result of deleterious alterations of genes that have final phenotypical effects similar to inactivation of the NF2 gene.
Intrapontomesencephalic colloid cyst: an unusual location
Authors: Inci Servet , Al-Rousan Nidal , Söylemezoglu Figen , Gurçay Özdemir
Published: May 2009

✓ Colloid cysts appear most commonly in the third ventricle; the occurrence of a colloid cyst in the brainstem is very unusual. The authors report on a patient with an intrapontomesencephalic colloid cyst. This 15-year-old girl complained of a headache associated with diplopia. Her neurological examination revealed right-sided sixth nerve paresis and a mild left hemiparesis. Radiological investigations revealed an intraparenchymal pontomesencephalic cystic mass. Surgical removal of the lesion was achieved via the pterional transsylvian approach and the patient experienced an excellent recovery. Histopathological examination revealed that the lesion was a typical colloid cyst.

To the best of the authors' knowledge, this is the first case in which an intraparenchymal upper brainstem colloid cyst was surgically excised totally. In addition to describing this case, the authors also review other brainstem neuroepithelial cysts described in the literature and briefly discuss the concept of their origin.
Focal hyperperfusion in a patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes
Authors: Amagasaki Kenichi , Shimizu Tsuneo , Suzuki Yoko , Kakizawa Toshiyuki
Published: May 2009

✓ 28-year-old woman presented with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS). The diagnosis was based on the results of molecular genetic analysis, which indicated a typical point mutation at the nucleotide pair 3243. Xenon computerized tomography scans obtained during the strokelike episodes revealed the lesion responsible for the symptoms to be an area of focal hyperperfusion, and scans obtained after the episodes revealed an area of hypoperfusion. Pathogenesis of the strokelike episodes appears to be metabolic dysfunction, although the involvement of a vascular event cannot be excluded.
Transcerebellomedullary fissure approach with special reference to the methods of dissecting the fissure
Authors: Matsushima Toshio , Inoue Tooru , Inamura Takanori , Natori Yoshihiro , Ikezaki Kiyonobu , Fukui Masashi
Published: May 2009

Object. The purpose of the present study was to refine the transcerebellomedullary fissure approach to the fourth ventricle and to clarify the optimal method of dissecting the fissure to obtain an appropriate operative view without splitting the inferior vermis.

Methods. The authors studied the microsurgical anatomy by using formalin-fixed specimens to determine the most appropriate method of dissecting the cerebellomedullary fissure. While dissecting the spaces around the tonsils and making incisions in the ventricle roof, the procedures used to expose each ventricle wall were studied. Based on their findings, the authors adopted the best approach for use in 19 cases of fourth ventricle tumor.

The fissure was further separated into two slit spaces on each side: namely the uvulotonsillar and medullotonsillar spaces. The floor of the fissure was composed of the tela choroidea, inferior medullary velum, and lateral recess, which form the ventricle roof. In this approach, the authors first dissected the spaces around the tonsils and then incised the taenia with or without the posterior margin of the lateral recess. These precise dissections allowed for easy retraction of the tonsil(s) and uvula and provided a sufficient view of the ventricle wall such that the deep aqueductal region and the lateral region around the lateral recess could be seen without splitting the vermis. The dissecting method could be divided into three different types, including extensive (aqueduct), lateral wall, and lateral recess, depending on the location of the ventricle wall and the extent of surgical exposure required.

Conclusions. When the fissure is appropriately and completely opened, the approach provides a sufficient operative view without splitting the vermis. Two key principles of this opening method are sufficient dissection of the spaces around the tonsil(s) and an incision of the appropriate portions of the ventricle roof. The taenia(e) with or without the posterior margin of the lateral recess(es) should be incised.
Augmentation of endothelial function by endothelin antagonism in human saphenous vein conduits
Authors: Dumont Aaron S. , Lovren Fina , McNeill John H. , Sutherland Garnette R. , Triggle Christopher R. , Anderson Todd J. , Verma Subodh
Published: May 2009

Object. Cerebral revascularization with saphenous vein (SV) conduits is used in the management of hard-to-treat lesions that require deliberate arterial occlusion and in selected patients with occlusive vascular disease. Endothelial dysfunction is thought to contribute to acute perioperative vasospasm and chronic graft atherosclerosis. In the present study the authors examined the contribution of the potent vasoconstrictor endothelin-1 (ET-1) to endothelial dysfunction in human SVs.

Methods. The effects of an ETA/B receptor antagonist (bosentan), an ETA receptor antagonist (BQ-123), and an ETB receptor antagonist (BQ-788) on in vitro endothelium-dependent and -independent responses were studied in human SVs. Vascular segments were obtained in 34 patients who had undergone revascularization procedures, and isometric dose—response curves (DRCs) were constructed using the isolated tissue bath procedure as follows: 1) cumulative DRCs to norepinephrine; and 2) DRCs to acetylcholine (ACh) and sodium nitroprusside in the absence and presence of bosentan, BQ-123, or BQ-788. Maximal vasodilatory responses and sensitivity were compared between groups. In the presence of bosentan (Experiment 1) and BQ-123 or BQ-788 (Experiment 2), ACh responses were significantly augmented (percent maximum relaxation values: 7 ± 2 [control] compared with 17 ± 3 [bosentan], p < 0.002 [Experiment 1]; and 12 ± 2 [control] compared with 29 ± 2 [BQ-123] and 25 ± 2 [BQ-788], p < 0.003 and p < 0.002, respectively [Experiment 2]). The sensitivity of SVs to ACh was unaffected by treatment. These beneficial effects were specific for the endothelium.

Conclusions. Blockade of ET receptors significantly improves endothelial function in SVs. Furthermore, these effects appear to be independently and maximally mediated by antagonism of either ETA or ETB receptors. Interventions aimed at improving endothelial function may serve to counter perioperative vasospasm and impede atherosclerosis in SVs used for revascularization procedures.
Establishment and characterization of a novel malignant astrocytoma cell line derived from a tumor removed in a patient with neurofibromatosis Type 1
Authors: Kurimoto Masanori , Hirashima Yutaka , Ogiichi Tsuneaki , Hamada Hideo , Kamiyama Hironaga , Endo Shunro
Published: May 2009

Object. Patients with neurofibromatosis Type 1 (NF1) have a predisposition to development of a variety of benign and malignant tumors including neurofibromas, astrocytomas, pheochromocytomas, and malignant peripheral nerve sheath tumors. The availability of an astrocytoma cell line derived from NF1 would be useful in studies in which sporadic astrocytomas could be compared with NF1-derived astrocytomas. In this article the authors describe a novel astrocytoma cell line, TM-31, that they established from a tumor removed in a 42-year-old woman with NF1.

Methods. The TM-31 cell line was prepared from a surgical specimen of malignant astrocytoma and was serially subcultured over 250 times throughout a 6-year period without showing any sign of cell senescence. Immunocytochemical analyses demonstrated that TM-31 cells are negative for glial fibrillary acidic protein but positive for vimentin and S-100 protein. The TM-31 cells display little neurofibromin expression when subjected to immunoblotting, indicating that there is an NF1 gene mutation. Polymerase chain reaction—single-strand conformational polymorphism analysis revealed that TM-31 cells harbor a p53 point mutation in exon 7, codon 238. Chemosensitivity testing of TM-31 cells revealed a resistance to 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea, although they are sensitive to cisplatin and etoposide. In addition, TM-31 cells displayed no morphological differentiation after all-transretinoic acid and dibutyryl cyclic adenosine monophosphate treatments. Pharmacological inhibition of farnesyltransferase of the Ras oncoprotein led to decreased proliferative activity and inhibition of anchorage-independent growth of TM-31 cells in soft agar.

Conclusions. The TM-31 cell line is an immortalized astrocytoma cell line derived from a tumor obtained in a patient with NF1. Ras activation may be the major event of proliferative activity and of the transformed phenotype of TM-31 cells, and the farnesyltransferase inhibitor may be potentially important as a novel antiproliferative therapy for NF1-derived astrocytomas.
Delayed onset of hemidystonia and hemiballismus following head injury: a clinicopathological correlation
Authors: King Robert B. , Fuller Christine , Collins George H.
Published: May 2009

✓ The authors report the case of a young man who suffered multiple injuries in a motor vehicle accident, the most significant of which arose in the brain, creating an unusual clinical syndrome. After experiencing an initial coma for several days, the patient was found to have a right-sided homonymous hemianopsia and a right hemiparesis, which was more marked at the shoulder and was accompanied by preservation of finger movement. Dystonic movements appeared 2 months later and progressed, along with increased spasticity on volition, to severe uncontrolled arm movements at 2 years postinjury. This motor disorder continued to worsen during the following 6 years prior to the patient's death. At autopsy, the left side of the brain was observed to have marked atrophy of the optic tract, a partial lesion of the posterior portion of the medial segment of the globus pallidus (GP), and a reduction in the size of the internal capsule at the level of the GP, suggesting impaired circulation to these areas at the time of injury. The isolated lesion of the internal segment of the GP was the presumed cause of the dystonia, acting through an alteration in thalamic inhibition. The atrophic subthalamic nucleus was the probable cause of the hemiballismus. The authors speculate that this and other delayed and progressive features of this case were the result of an active, but disordered, adaptive process that failed to compensate and, instead, caused even greater problems than the original injury.
Giant chondroma arising from the dura mater of the convexity
Authors: Nakayama Masaki , Nagayama Tetsuya , Hirano Hirofumi , Oyoshi Tatsuki , Kuratsu Jun-ichi
Published: May 2009

✓ Chondromas arising from the dura mater are rare intracranial tumors. The authors present a case of intracranial giant chondroma originating from the dura mater of the convexity. Neuroimaging and surgical findings are described. The diagnostic clues are discussed and similar cases from the literature are reviewed.
Supracerebellar transtentorial approach to posterior temporomedial structures
Authors: Yonekawa Yasuhiro , Imhof Hans-Georg , Taub Ethan , Curcic Marijan , Kaku Yasuhiko , Roth Peter , Wieser Heinz Gregor , Groscurth Peter
Published: May 2009

✓ The supracerebellar transtentorial (SCTT) approach, a modification of the infratentorial supracerebellar approach, facilitates simple and minimally invasive access to posterior temporomedial structures without requiring retraction of the temporal or occipital lobe.

The SCTT approach was used in 16 patients over a 3-year period. Eleven patients harbored tumors confined to, or located mainly within, the posterior hippocampal formation, three patients harbored aneurysms (one ruptured posterior cerebral artery [PCA] aneurysm at the P2-P3 junction, one ruptured giant PCA [P2] aneurysm, and one giant basilar artery—superior cerebellar artery aneurysm), one patient had juvenile-type moyamoya disease, and one patient suffered from medically intractable epilepsy. In these patients, the SCTT approach enabled tumor removal, aneurysm clipping, and vascular bypass procedures.

The authors' experience suggests that this approach can be used routinely in treating lesions in the posterior temporomedial region.
Enigma of raised intracranial pressure in patients with complex craniosynostosis: the role of abnormal intracranial venous drainage
Authors: Taylor Wendy J. , Hayward Richard D. , Lasjaunias Pierre , Britto Jonathan A. , Thompson Dominic N. P. , Jones Barry M. , Evans Robert D.
Published: May 2009

Object. In this study the authors investigated whether patterns of intracranial venous drainage in children with complex craniosynostosis associated with raised intracranial pressure (ICP) were abnormal and, thus, could support the theory that venous hypertension is a major contributor to raised ICP that can lead to impaired visual function or even blindness in these patients.

Methods. The authors analyzed the anatomy of intracranial venous drainage as demonstrated in the results of 24 angiography studies obtained in 23 patients, all of whom had either a craniosynostosis-related syndrome (18 patients) or a nonsyndromic multisutural synostosis (five patients). Twenty-one patients had experienced raised ICP (in 19 patients diagnosis was based on invasive ICP monitoring and in two patients on clinical grounds alone) 1 to 6 weeks before undergoing angiography. Of the two remaining patients (both with Apert syndrome) whose ICP monitoring was normal immediately before angiography, each had undergone two previous cranial vault expansion procedures.

On results of 18 angiography studies a 51 to 99% stenosis or no flow at all could be observed in the sigmoid—jugular sinus complex either bilaterally (11 patients) or unilaterally (seven patients). In 11 of these patients a florid collateral circulation through the stylomastoid emissary venous plexus was also seen. Two angiography studies were performed in one patient with Crouzon syndrome. A comparison of the two studies demonstrated a progression of the abnormal venous anatomy in that case. The authors found no obvious correlation between each patient's baseline ICP and the degree of abnormality of their venous anatomy, as judged on the basis of a venous-phase angiography severity score.

Conclusions. Based on their findings, the authors assert that in children with complex forms of craniosynostosis in whom other factors, such as hydrocephalus, are absent, abnormalities of venous drainage that particularly affect the sigmoid—jugular sinus complex produce a state of venous hypertension that, in turn, is responsible for the majority of cases of raised ICP. The incidence of these changes is unknown, but an analysis of the ages of the children in this study indicated that the period of particular vulnerability to the effects of venous hypertension lasts until the affected child is approximately 6 years old. After that age the collateral venous drainage through the stylomastoid plexus will likely become sufficient to allow ICP to normalize.
Two computerized methods used to analyze intracranial pressure B waves: comparison with traditional visual interpretation
Authors: Eklund Anders , Ågren-Wilsson Aina , Andersson Nina , Bergenheim A. Tommy , Koskinen Lars-Owe D. , Malm Jan
Published: May 2009

Object. Slow and rhythmic oscillations in intracranial pressure (ICP), also known as B waves, have been claimed to be one of the best preoperative predictive factors in idiopathic adult hydrocephalus syndrome (IAHS). Definitions of B waves vary widely, and previously reported results must be treated with caution. The aims of the present study were to develop a definition of B waves, to develop a method to estimate the B-wave content in an ICP recording by using computer algorithms, and to validate these procedures by comparison with the traditional visual interpretation.

Methods. In eight patients with IAHS, ICP was continuously monitored for approximately 20 hours. The ICP B-wave activity as a percentage of total monitoring time (B%) was estimated by using visual estimation according to the definition given by Lundberg, and also by using two computer algorithms (Methods I and II). In Method I each individual wave was classified as a B wave or not, whereas Method II was used to estimate the B-wave content by evaluating the B-wave power in 10-minute blocks of ICP recordings.

Conclusions. The two computerized algorithms produced similar results. However, with the amplitude set to 1 mm Hg, Method I yielded the highest correlation with the visual analysis (r = 0.74). At least 5 hours of monitoring time was needed for an acceptable approximation of the B% in an overnight ICP recording. The advantages of using modern technology in the analysis of B-wave content of ICP are obvious and these methods should be used in future studies.
Effects of hyperbaric oxygenation therapy on cerebral metabolism and intracranial pressure in severely brain injured patients
Authors: Rockswold Sarah B. , Rockswold Gaylan L. , Vargo Janet M. , Erickson Carla A. , Sutton Richard L. , Bergman Thomas A. , Biros Michelle H.
Published: May 2009

Object. Hyperbaric oxygenation (HBO) therapy has been shown to reduce mortality by 50% in a prospective randomized trial of severely brain injured patients conducted at the authors' institution. The purpose of the present study was to determine the effects of HBO on cerebral blood flow (CBF), cerebral metabolism, and intracranial pressure (ICP), and to determine the optimal HBO treatment paradigm.

Methods. Oxygen (100% O2, 1.5 atm absolute) was delivered to 37 patients in a hyperbaric chamber for 60 minutes every 24 hours (maximum of seven treatments/patient). Cerebral blood flow, arteriovenous oxygen difference (AVDO2), cerebral metabolic rate of oxygen (CMRO2), ventricular cerebrospinal fluid (CSF) lactate, and ICP values were obtained 1 hour before and 1 hour and 6 hours after a session in an HBO chamber. Patients were assigned to one of three categories according to whether they had reduced, normal, or raised CBF before HBO.

In patients in whom CBF levels were reduced before HBO sessions, both CBF and CMRO2 levels were raised 1 hour and 6 hours after HBO (p < 0.05). In patients in whom CBF levels were normal before HBO sessions, both CBF and CMRO2 levels were increased at 1 hour (p < 0.05), but were decreased by 6 hours after HBO. Cerebral blood flow was reduced 1 hour and 6 hours after HBO (p < 0.05), but CMRO2 was unchanged in patients who had exhibited a raised CBF before an HBO session. In all patients AVDO2 remained constant both before and after HBO. Levels of CSF lactate were consistently decreased 1 hour and 6 hours after HBO, regardless of the patient's CBF category before undergoing HBO (p < 0.05). Intracranial pressure values higher than 15 mm Hg before HBO were decreased 1 hour and 6 hours after HBO (p < 0.05). The effects of each HBO treatment did not last until the next session in the hyperbaric chamber.

Conclusions. The increased CMRO2 and decreased CSF lactate levels after treatment indicate that HBO may improve aerobic metabolism in severely brain injured patients. This is the first study to demonstrate a prolonged effect of HBO treatment on CBF and cerebral metabolism. On the basis of their data the authors assert that shorter, more frequent exposure to HBO may optimize treatment.
Functional outcome after repair of unruptured intracranial aneurysms
Authors: Chyatte Douglas , Porterfield Rebecca
Published: May 2009

Object. Repair of unruptured aneurysms is a reasonable course of action if their expected natural history is worse than the predicted risks of treatment. The purpose of this study was to examine the presenting symptoms of unruptured aneurysms and to test the hypothesis that unruptured intracranial aneurysms can be repaired without significant functional worsening. A second hypothesis was also examined—that is, that the experience of the surgeon, the aneurysm size, and the patient age can be used to predict functional outcome.

Methods. Consecutive patients who underwent repair of an unruptured intracranial aneurysm at a single institution between 1980 and 1998 were studied. Clinical and radiographic data were collected in all patients. Their modified Rankin Scale (mRS) score was determined before treatment (baseline), at 6 weeks, and at 6 months. The primary endpoint for analysis was the mRS score.

Four hundred forty-nine aneurysms were repaired in 366 patients by 10 surgeons. The mean size of the primary lesion repaired was 14.6 + 10.4 mm and 27% were judged to be symptomatic. Aneurysm treatment involved either microsurgical clipping (78%), wrapping (4%), trapping with or without bypass (5%), hunterian ligation with or without bypass (9%), or other methods (4%). The mRS scores at 6 weeks were worse than at baseline (p < 0.0001), but there was no significant difference between the baseline and 6-month mRS score. At 6 months, 94% of patients showed no significant functional worsening as a result of treatment. The number of aneurysms treated by a specific surgeon was a strong predictor of better functional outcome (r = 0.99, p = 0.05). Increasing patient age (r = 0.16, p = 0.003) and increasing aneurysm size (r = 0.15, p = 0.004) were predictors of worsened functional outcome.

Conclusions. Many unruptured aneurysms produce symptoms. Unruptured intracranial aneurysms can be treated without significant permanent functional worsening. The surgeon's experience, aneurysm size, and patient age are predictors of functional outcome.
Magnetic source imaging of late evoked field responses to vowels: toward an assessment of hemispheric dominance for language
Authors: Szymanski Michael D. , Perry David W. , Gage Nicole M. , Rowley Howard A. , Walker John , Berger Mitchel S. , Roberts Timothy P. L.
Published: May 2009

Object. The goal of this study was to determine whether the late neuromagnetic field elicited by simple speech sounds, which is detected by magnetoencephalography, may be used to estimate hemispheric dominance for language and to guide or constrain the intraoperative search for essential language sites. If sufficiently robust, a noninvasive method for assessing hemispheric dominance for language could reduce the necessity for amobarbital testing and the extent of intraoperative cortical stimulation—based mapping, both of which carry the risk of morbidity.

Methods. Fifteen patients undergoing surgery for tumors during which intraoperative language mapping would be performed and two additional patients in whom intracarotid amobarbital testing confirmed right-hemisphere language dominance participated. Following a primary auditory response sources of late neuromagnetic fields elicited by vowel stimuli were modeled and coregistered using magnetic resonance images to form magnetic source (MS) images. A laterality index (LI) was calculated by summing the number of equivalent current dipolar sources in the late fields detected from each hemisphere. In 14 right-handed patients, 10 displayed left asymmetric LIs (0.37 ± 0.16, mean ± standard error of the mean in 14 patients). For both right-hemisphere dominant patients in whom an LI was obtainable, the LI was rightward. Stimulation-mapped essential language sites were found in 7 of 15 patients. For six of these seven patients, the MS image—derived LI was leftward.

Conclusions. Asymmetry in single equivalent dipole modeling of the late neuromagnetic field evoked by simple speech sounds correlates with hemispheric language dominance, although not to the degree necessary for individual clinical predictions. With further development, MS imaging of simple language tasks may be used preoperatively to predict language dominance and even to identify or constrain the intraoperative search for likely sites of essential language cortex.
Bioabsorbable polymeric material coils for embolization of intracranial aneurysms: a preliminary experimental study
Authors: Murayama Yuichi , Viñuela Fernando , Tateshima Satoshi , Song Joon K. , Gonzalez Nestor R. , Wallace Michael P.
Published: May 2009

Object. A new embolic agent, bioabsorbable polymeric material (BPM), was incorporated into Guglielmi detachable coils (GDCs) to improve long-term anatomical results in the endovascular treatment of intracranial aneurysms. The authors investigated whether BPM-mounted GDCs (BPM/GDCs) accelerated the histopathological transformation of unorganized blood clot into fibrous connective tissue in experimental aneurysms created in swine.

Methods. Twenty-four experimental aneurysms were created in 12 swine. In each animal, one aneurysm was embolized using BPM/GDCs and the other aneurysm was embolized using standard GDCs. Comparative angiographic and histopathological data were analyzed at 2 weeks and 3 months postembolization.

At 14 days postembolization, angiograms revealed evidence of neck neointima in six of eight aneurysms treated with BPM/GDCs compared with zero of eight aneurysms treated with standard GDCs (p < 0.05). At 3 months postembolization, angiograms demonstrated that four of four aneurysms treated with BPM/GDC were smaller and had neck neointima compared with zero of four aneurysms treated with standard GDCs (p = 0.05). At 14 days, histological analysis of aneurysm healing favored BPM/GDC treatment (all p < 0.05): the grade of cellular reaction around the coils was 3 ± 0.9 (mean ± standard deviation) for aneurysms treated using BPM/GDCs compared with 1.6 ± 0.7 for aneurysms treated using GDCs alone; the percentage of unorganized thrombus was 16 ± 12% compared with 37 ± 15%, and the neck neointima thickness was 0.65 ±0.26 mm compared with 0.24 ±0.21 mm, respectively. At 3 months postembolization, only neck neointima thickness was significantly different (p < 0.05): 0.73 ± 0.37 mm in aneurysms filled with BPM/GDCs compared with 0.16 ± 0.14 mm in aneurysms filled with standard GDCs.

Conclusions. In experimental aneurysms in swine, BPM/GDCs accelerated aneurysm fibrosis and intensified neck neointima formation without causing parent artery stenosis or thrombosis. The use of BPM/GDCs may improve long-term anatomical outcomes by decreasing aneurysm recanalization due to stronger in situ anchoring of coils by organized fibrous tissue. The retraction of this scar tissue may also decrease the size of aneurysms and clinical manifestations of mass effect observed in large or giant aneurysms.
Roles of membrane type 1 matrix metalloproteinase and tissue inhibitor of metalloproteinases 2 in invasion and dissemination of human malignant glioma
Authors: Nakada Mitsutoshi , Kita Daisuke , Futami Kazuya , Yamashita Junkoh , Fujimoto Noboru , Sato Hiroshi , Okada Yasunori
Published: May 2009

Object. Acquisition of invasive and metastatic potentials through proteinase expression is an essential event in tumor progression. Among proteinases, matrix metalloproteinases (MMPs) are thought to play a key role in tumor progression through the degradation of the extracellular matrix. In the present study, the authors examined the role of MMP-2 (gelatinase A) and membrane type 1 MMP (MT1-MMP), an activator of the zymogen of MMP-2, proMMP-2, together with tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) in the invasion of astrocytic tumors in humans.

Methods. Analyses performed using sandwich enzyme immunoassays demonstrated that the production levels of proMMP-2 and TIMP-1, but not TIMP-2, are significantly higher in glioblastomas multiforme than in other grades of astrocytic tumors. Quantitative reverse transcription-polymerase chain reaction indicated that MT1-MMP is expressed predominantly in glioblastoma tissues, and its expression levels are significantly enhanced as tumor grade increases. In addition, the expression levels and proMMP-2 activation ratio were remarkably higher in glioblastomas associated with cerebrospinal fluid (CSF) dissemination than in those not associated with CSF dissemination. In contrast, an examination of TIMP-2 levels showed a reverse correlation. Like MT1-MMP, TIMP-1 and TIMP-2 were immunolocalized to neoplastic cells in glioblastoma samples. To study the roles of these molecules in the invasion of astrocytic tumors more fully, stable transfectants expressing the MT1-MMP gene were developed in a U251 human glioblastoma cell line. The MT1-MMP transfectants displayed prominent activation of proMMP-2 and invasive growth in three-dimensional collagen gel; however, mock transfectants and parental cells displayed noninvasive growth without the activation. The invasion and gelatinolytic activity of the transfectants were completely inhibited by addition of recombinant TIMP-2, but not recombinant TIMP-1.

Conclusions. These results indicate that MT1-MMP may contribute to tumor invasion and CSF dissemination of glioblastoma cells on the basis of an imbalance of TIMP-2.
Enhancement of antitumor immune response in glioma models in mice by genetically modified dendritic cells pulsed with Semliki Forest virus—mediated complementary DNA
Authors: Yamanaka Ryuya , Zullo Susan A. , Tanaka Ryuichi , Blaese Michael , Xanthopoulos Kleanthis G.
Published: May 2009

Object. The aim of this study was to further investigate dendritic cell (DC)—based immunotherapy for malignant glioma to improve its therapeutic efficacy.

Methods. Dendritic cells were isolated from the bone marrow and pulsed with phosphate-buffered saline, tumor RNA, tumor lysate, Semliki Forest virus (SFV)-LacZ, SFV-mediated B16 complementary (c)DNA, or SFV-mediated 203 glioma cDNA, respectively, to treat mice bearing tumors of the 203 glioma cell line. The results indicated that preimmunization with DCs pulsed with the same type of cDNA as in the tumor by a self-replicating RNA vector (that is, SFV) protected mice from tumor challenge, and that therapeutic immunization prolonged the survival of mice with established tumors. The SFV induced apoptosis in DCs and their death facilitated the uptake of apoptotic cells by other DCs, thus providing a potential mechanism for enhanced immunogenicity.

Conclusions. Therapy with DCs that have been pulsed with SFV-mediated tumor cDNA may be an excellent procedure for the development of new cancer vaccines.