bluuebunny/crossref_metadata_2025_split huggingface dataset:
Embolization of a common carotid aneurysm with rhVEGF coupled to a pH-responsive chitosan in a rat model
Authors: Pan Hui , Zimmerman Thomas , Zakhaleva Julia , Abrahams John M. , Jiang Hongliang , Chen Weiliam 
Published: August 2009

Object
Treatment of cerebral aneurysms by endovascular deployment of liquid embolic agents has been proposed as an alternative strategy to conventional coiling, and new materials are being developed for embolization. In this study, the authors used a single-injection, biocompatible, biodegradable and pH-responsive acrylated chitosan (aCHN) with conjugated vascular endothelial growth factor (rhVEGF) in a rat aneurysm model.

Methods
The efficacy of the aCHN formulation with rhVEGF was tested using a common carotid artery occlusion model in rats, and the extent of embolization was evaluated using quantitative, qualitative, and histopathological techniques after 14 days of implantation.

Results
The mean occlusion was significantly greater for the rhVEGF/aCHN-treated group (96.8 ± 3.0%) than for the group receiving aCHN (74.7 ± 5.6%) (p < 0.01). Through qualitative evaluation, intimal and medial proliferation were significantly greater with rhVEGF/aCHN than with aCHN and controls (p < 0.001). Degradation of the aCHN filler was monitored in concert with the production of extracellular matrix components. Macrophages migrated in and proliferated inside the occluded carotid artery lumens were identified by histological and immunostainings. Results showed resorption of chitosan with concurrent development of collagen and elastin into the vessel lumen, suggesting clot maturation into fibrosis.

Conclusions
Chitosan with a bioactive agent such as rhVEGF showed excellent results in occluding aneurysms in a rat model.
Endoscopic management of spontaneous meningoencephalocele of the lateral sphenoid sinus
Authors: Tabaee Abtin , Anand Vijay K. , Cappabianca Paolo , Stamm Aldo , Esposito Felice , Schwartz Theodore H. 
Published: August 2009

Object
Spontaneous meningoencephaloceles of the lateral sphenoid sinus are rare lesions that are hypothesized to result from persistence of the lateral craniopharyngeal canal. Prior reports of the management of this lesion have been limited by its relative rarity. The objective of this paper is to report the theoretical etiology, surgical technique, and outcomes in patients undergoing endoscopic repair of spontaneous meningoencephalocele of the sphenoid sinus.

Methods
The authors conducted a retrospective review of a multiinstitutional series of 13 cases involving patients who underwent endoscopic repair of spontaneous meningoencephalocele of the lateral sphenoid sinus. The surgical technique and pathophysiological considerations are discussed.

Results
The clinical manifestations included CSF rhinorrhea (85%), chronic headache (77%), and a history of meningitis (15%). The endoscopic approaches to the lateral sphenoid sinus were transnasal (39%), transpterygoid (23%), and transethmoid (39%). Two patients (8%) had postoperative CSF leaks, one of which closed spontaneously and one of which required revision endoscopic closure. All patients were free of leak at most recent follow-up. One patient experienced postoperative meningitis in the early postoperative period.

Conclusions
Endoscopic endonasal closure is an effective modality in the treatment of spontaneous meningoencephaloceles of the lateral sphenoid sinus. If the sphenoid sinus has extensive lateral pneumatization, adequate exposure may require a transpterygoid approach.
Significance of postoperative fluid diuresis in patients undergoing transsphenoidal surgery for growth hormone–secreting pituitary adenomas
Authors: Zada Gabriel , Sivakumar Walavan , Fishback Dawn , Singer Peter A. , Weiss Martin H. 
Published: August 2009

Object
Following successful transsphenoidal surgery in patients with growth hormone (GH)–secreting pituitary adenomas, a characteristic fluid diuresis has been described. In this paper the authors aimed to further analyze the degree of fluid diuresis as it relates to postoperative GH levels.

Methods
Between 2000 and 2008, 85 patients underwent transsphenoidal surgery for a GH-secreting adenoma at the USC University Hospital. A retrospective chart review was conducted. Postoperative fluid intake, output, and balance within 48 hours following surgery, as well as endocrinological data were recorded and analyzed. Patients with postoperative diabetes insipidus and those with insufficient data were excluded from analysis.

Results
Seventy-one patients were included in the analysis. The mean age was 46 years (range 16–74 years). There were 36 males (51%) and 35 females (49%). Patients with negative fluid balances at 48 hours after surgery were more than twice as likely to have a GH level of < 1.5 ng/ml (55 vs 25%, p = 0.023). At 48 hours after surgery, patients with a negative overall fluid balance had a significantly lower median GH level than those with a positive overall fluid balance (1.3 vs 2.4 ng/ml, p = 0.039). This difference was even more pronounced in patients with microadenomas and a negative overall fluid balance. By 48 hours following surgery, patients with postoperative Day 1 GH levels < 1.5 ng/ml had, on average, experienced diuresis of fluid > 1.1 L (median 1.5 L) more than patients with GH levels > 1.5 ng/ml.

Conclusions
Successful resection of GH-secreting adenomas is associated with a more pronounced fluid diuresis and negative overall fluid balance within 48 hours following transsphenoidal surgery. Patients with a negative fluid balance by postoperative Day 2 have a higher likelihood of having significantly reduced postoperative GH levels that may correlate with long-term surgical remission.
Fibroblast growth factor receptor–3 expression in meningiomas with stimulation of proliferation by the phosphoinositide 3 kinase–Akt pathway
Authors: Johnson Mahlon D. , O'Connell Mary J. , Pilcher Webster , Reeder Jay E. 
Published: August 2009

Object
Fibroblast growth factor receptors (FGFRs)–1, –2, and –3 are expressed in the developing brain and may participate in CNS neoplasia. Fibroblast growth receptor–3 has not been demonstrated in the human CNS or its tumors. Nonetheless, it has been implicated in the pathogenesis of several other forms of neoplasia.

Methods
Twenty-four human meningiomas were evaluated using Western blot analysis for expression of FGFR3, its ligand acidic FGF, and concomitant phosphorylation/activation of p44/42 mitogen-activated protein kinase (MAPK), Akt, and STAT3. Mutations in exons 7 and 10 of the FGFR3 gene were analyzed by polymerase chain reaction in 10 meningiomas. Primary meningioma cells cultured from 10 human meningiomas were also treated with acidic FGF and evaluated for cell proliferation or activation/phosphorylation of p44/42 MAPK, Akt, and STAT3.

Results
Immunoblotting demonstrated the presence of FGFR3 in 12 (71%) of 17 primarily fibroblastic and transitional WHO Grade I meningiomas. The FGFR3 was detected in 4 (80%) of 5 WHO Grade II, and 2 of 2 Grade III tumors. Acidic FGF was detected in 3 (18%) of 17 Grade I, 1 (20%) of 5 Grade II, and 1 (50%) of 2 Grade III meningiomas. In WHO Grade I meningiomas, 3 of 6 tumors with no detectable FGFR3 had no detectable p-STAT3. In WHO Grades II and III meningiomas, FGFR3 expression was associated with p-STAT3, p-Akt, and p-p44/42 MAPK expression. No mutations were demonstrated in exons 7 or 10 by polymerase chain reaction in any meningioma. Treatment with acidic FGF, a ligand for FGFR3, stimulated meningioma cell proliferation and activation of Akt and STAT3 in primary meningioma cell cultures.

Conclusions
These findings suggest that FGFR3 and acidic FGF are expressed in adult human leptomeninges as well as WHO Grades I and II meningiomas. Fibroblast growth factor receptor–3 activation stimulates meningioma cell proliferation by activation of the phosphoinositide 3 kinase–Akt-PRAS40-mTOR and STAT3 pathways.
Postoperative radiographic findings in patients undergoing intracranial electrode monitoring for medically refractory epilepsy
Authors: Albert Gregory W. , Dahdaleh Nader S. , Reddy Chandan , Hansen Daniel R. , Vogel Timothy W. , Kawasaki Hiroto , Howard Matthew A. 
Published: August 2009

Object
In this study the authors sought to determine whether any correlations existed between postimplantation head CT findings and the need to perform decompression surgery in patients with grid electrodes.

Methods
The authors identified 74 patients who underwent intracranial electrode monitoring for medically refractory epilepsy from January 2000 through June 2008. Only the 46 patients who had head CT scans available for review were included in the study. The authors were able to determine the number and types of electrodes placed as well as complications experienced. They reviewed the CT scans for abnormal findings including extraaxial fluid collections, intracranial hemorrhages, and signs of mass effect.

Results
All patients developed some degree of extraaxial fluid collection following the placement of intracranial electrodes. The maximum width of the extraaxial fluid collection and the degree of midline shift were not predictive of the need for decompressive surgery. The presence, but not degree, of midline shift was associated with the need for decompressive surgery. Likewise, the presence of ventricular asymmetry was correlated with the need for removal of the electrodes and bone flap. Patients without midline shift or ventricular asymmetry on CT did not require decompressive surgery.

Conclusions
After undergoing placement of intracranial electrodes all patients develop extraaxial fluid collections. In addition, many patients develop signs of mass effect including midline shift and ventricular asymmetry. When these findings are absent it is highly unlikely that surgical decompression is required.
A large-scale numerical model for computing isochrone geometry
Authors: Hindmarsh Richard C.A. , Leysinger Vieli Gwendolyn J.-M.C. , Parrenin Frédéric 
Published: August 2009

AbstractA finite-difference model for the calculation of radar layer geometries in large ice masses is presented. Balance velocities are used as coefficients in the age equation and in the heat equation. Solution of the heat equation allows prediction of sliding areas and computation of basal melt rates. Vertical distributions of velocity are parameterized using shape functions. These can be set uniformly, or allowed to vary in space according to the distribution of sliding. The vertical coordinate can either be uniformly distributed within the thickness of the ice, or be uniformly distributed within the flux. The finite-difference scheme results in a large set of linear equations. These are solved using a nested factorization preconditioned conjugate gradient scheme. The convergence properties of some other iteration solution schemes are studied. The output is computations of age and temperature assuming steady state, in large ice masses at high resolution. Age calculations are used to generate isochrones which show the best fit to observed layers. Comparisons with analytical solutions are made, and the influence of the order of the finite-difference approximation and the choice of vertical coordinate on solution accuracy is considered.
Radar surveys of the Rutford Ice Stream onset zone, West Antarctica: indications of flow (in)stability?
Authors: Woodward John , King Edward C. 
Published: August 2009

AbstractWe present 1 and 100 MHz ground-based radar data from the onset region of Rutford Ice Stream, West Antarctica, which indicate the form and internal structure of isochrones. In the flow-parallel lines, modelled isochrone patterns reproduce the gross pattern of the imaged near-surface layers, assuming steady-state flow velocity from GPS records and the current accumulation rate for the last 200 years. We interpret this as indicating overall stability in flow in the onset region of Rutford Ice Stream throughout this period. However, in the cross-flow lines some local variability in accumulation is seen in areas close to the ice-stream margin where a number of tributaries converge towards the ice-stream onset zone. Episodic surface lowering events are observed followed by rapid fill episodes. The fill events indicate deposition towards the northwest, most likely generated by storm winds, which blow at an oblique angle to ice flow. More problematic is explaining the generation of episodic surface lowering in this area. We speculate this may be due to: changing ice-flow direction in the complex tributary area of the onset zone; a change in basal sediments or sedimentary landforms; a change in basal melt rates or water supply; or episodic lake drainage events in the fjord systems of the Ellsworth Subglacial Highlands. The study highlights the difficulty of assessing flow stability in the complex onset regions of West Antarctic ice streams.
Ice thickness, internal structure and subglacial topography of Bowles Plateau ice cap and the main ice divides of Livingston Island, Antarctica, by ground-based radio-echo sounding
Authors: Macheret Yu.Ya. , Otero J. , Navarro F.J. , Vasilenko E.V. , Corcuera M.I. , Cuadrado M.L. , Glazovsky A.F. 
Published: August 2009

AbstractWe present the results of low-frequency (20 MHz) radio-echo sounding (RES) carried out in December 2000 and December 2006 on the main ice divides of Livingston Island, South Shetland Islands (SSI), Antarctica, and Bowles Plateau, Antarctica, respectively, as well as high-frequency (200 MHz) RES on the latter, aimed at determining the ice thickness, internal structure and subglacial relief. Typical ice thickness along the main ice divides is ~150 m, reaching maxima of ~200 m. On Bowles Plateau the ice is much thicker, with an average of 265 m and maxima of ~500 m. The bed below the main ice divides is above sea level, while part of the outlet glaciers from Bowles Plateau lies significantly below sea level, down to –120 m. The strong scattering of the radio waves in the areas under study constitutes further evidence that the ice in the accumulation area of the ice masses of the SSI is temperate. Typical thickness of the firn layer in Bowles Plateau is 20–35 m, similar to that found in King George ice cap. A strong internal reflector within the firn layer, interpreted as a tephra layer from the 1970 eruption at Deception Island, has allowed a rough estimate of the specific mass balances for Bowles Plateau within 0.20–0.40ma–1w.e., as average values for the period 1970–2006.
A low-frequency ice-penetrating radar system adapted for use from an airplane: test results from Bering and Malaspina Glaciers, Alaska, USA
Authors: Conway Howard , Smith Ben , Vaswani Pavan , Matsuoka Kenichi , Rignot Eric , Claus Paul 
Published: August 2009

AbstractIce-thickness measurements are needed to calculate fluxes through fast-flowing outlet glaciers in Greenland, Alaska, Patagonia and Antarctica. However, relatively high attenuation of radio waves by dielectric absorption and volume scattering from englacial water hampers detection of the bed through warm deep ice. In the past we have had success measuring ice thickness of temperate glaciers using a ground-based monopulse radar system operating at low frequencies (2 MHz). Here we adapt the same system to operate from an airplane. Test flights over Bering Glacier, Alaska, USA, detected the bed through ice up to 1250m thick. Flights across the Seward–Malaspina Glacier system, Alaska, resolved the ice thickness of Malaspina Glacier, but strong hyperbolic-shaped returns obscured the bed echo through the Seward throat. It is likely that this clutter in the signal was caused by off-nadir returns from chaotic surface crevasses that are ubiquitous in the throat region.
First results from radar profiles collected along the US-ITASE traverse from Taylor Dome to South Pole (2006–2008)
Authors: Welch Brian C. , Jacobel Robert W. , Arcone Steven A. 
Published: August 2009

AbstractThe 2006/07 and 2007/08 US-ITASE traverses from Taylor Dome to South Pole in East Antarctica provided opportunities to survey the subglacial and englacial environments using 3 MHz and 200MHz radar. We present first results of these new ground-based radar data. A prominent basal deformation layer indicates different ice-flow regimes for the northern and southern halves of the Byrd Glacier drainage. Buried dune stratigraphy that appears to be related to the megadunes towards the west occurs at depths of up to 1500 m. At least two new water-filled subglacial lakes were discovered, while two recently drained lakes identified from repeat ICESat surface elevation surveys appear to be devoid of water.
Spatial variation of radar-derived basal conditions on Kamb Ice Stream, West Antarctica
Authors: Jacobel Robert W. , Welch Brian C. , Osterhouse David , Pettersson Rickard , MacGregor Joseph A. 
Published: August 2009

AbstractRadar profiles of bed echo intensity can survey conditions at the ice–bed interface and test for the presence or absence of water. However, extracting information about basal conditions from bed echo intensities requires an estimate of the attenuation loss through the ice. We used the relationship between bed echo intensities from constant-offset radar data and ice thickness to estimate depth-averaged attenuation rates at several locations on and near Kamb Ice Stream (KIS), West Antarctica. We found values varying from 29 dBkm–1at Siple Dome to 15 dBkm–1in the main trunk region of KIS, in agreement with a previous measurement and models. Using these attenuation-rate values, we calculated the relative bed reflectivity throughout our KIS surveys and found that most of the bed in the trunk has high basal reflectivities, similar to those obtained in the location of boreholes that found water at the bed. Areas of lower bed reflectivity are limited to the sticky spot, where a borehole found a dry bed, and along the margins of KIS. These results support previous hypotheses that the basal conditions at locations like the sticky spot on KIS control its stagnation and possible reactivation.
Past and present accumulation rate reconstruction along the Dome Fuji–Kohnen radio-echo sounding profile, Dronning Maud Land, East Antarctica
Authors: Huybrechts Philippe , Rybak Oleg , Steinhage Daniel , Pattyn Frank 
Published: August 2009

AbstractWe used internal ice layers from a radio-echo sounding profile between the Kohnen and Dome Fuji deep drilling sites to infer the spatio-temporal pattern of accumulation rate in this sector of Dronning Maud Land, East Antarctica. Continuous internal reflection horizons can be traced to about half of the ice thickness and have a maximum age of approximately 72.7 ka BP. To infer palaeo-accumulation rates from the dated layers, we derived the thinning functions from a flow calculation with a high-resolution higher-order model of Dronning Maud Land embedded into a three-dimensional thermomechanical model of the Antarctic ice sheet. The method takes into account complex ice-flow dynamics and advection effects that cannot be dealt with using traditional local approaches. We selected seven time intervals over which we determine the average accumulation rate and average surface temperature at the place and time of origin of the layer particles. Our results show lower accumulation rates along eastern parts of the profile for the late Holocene (0–5 ka BP) than are shown by existing maps, which had no surface control points. During the last glacial period we find a substantially lower accumulation rate than predicted by the usual approach linking palaeo-accumulation rates to the condensation temperature above the surface inversion layer. These findings were used to fine-tune the relation between accumulation rate and temperature.
Determination of total ice volume and ice-thickness distribution of two glaciers in the Hohe Tauern region, Eastern Alps, from GPR data
Authors: Binder D. , Brückl E. , Roch K.H. , Behm M. , Schöner W. , Hynek B. 
Published: August 2009

AbstractGlobal warming is causing an apparent rapid retreat of many glaciers worldwide. In addition to mass-balance investigation, the determination and monitoring of total glacial ice volume and ice-thickness distribution are important parameters for understanding the interactions between climate and the complex glacier system. Because of spatially irregular and sparse datasets, scaling of volume and ice-thickness distribution is often a challenging problem. This study focuses on two small (<2 km2) temperate glaciers in the Hohe Tauern (Eastern Alps) region of central Austria. The period 2003–04 saw the first use of ground-penetrating radar (GPR) to determine the total ice volume and ice-thickness distribution of the two glaciers. A centre frequency of 20 MHz was used in point measuring mode. Despite variable data quality, bedrock reflections up to depths of >100m were identified in the data. The acquired GPR data are irregularly distributed and the spatial density is too low to calculate reasonable bedrock topography with standard interpolation approaches. Thus one main focus of this study was to develop an appropriate interpolation technique. Eventually, kriging technique and a glacial mechanically based interpolation parameter were used. Mean calculated ice thicknesses for the two investigated glaciers are 40–50 m, with a maximum of 150–165 m. No direct validation data are available, so different considerations support the computed bedrock topography.
GPR reflection profiles of Clark and Commonwealth Glaciers, Dry Valleys, Antarctica
Authors: Arcone Steven A. , Kreutz Karl 
Published: August 2009

AbstractEnglacial horizons deeper than 100m are absent within 100MHz ground-penetrating radar (GPR) surface profiles we recorded on Clark and Commonwealth Glaciers in the Antarctic Dry Valleys region. Both glaciers show continuous bottom horizons to 280 m, with bottom signal-to-noise ratios near 30 dB. Density horizons should fade below 50 m depth because impermeable ice occurred by 36 m. Folding within Commonwealth Glacier could preclude radar strata beneath about 80 m depth, but there is no significant folding within Clark Glacier. Strong sulfate concentrations and contrasts exist in our shallow ice core. However, it appears that high background concentration levels, and possible decreased concentration contrasts with depth placed their corresponding reflection coefficients at the limit of, or below, our system sensitivity by about 77m depth. Further verification of this conclusion awaits processing of our deep-core chemistry profiles.
Continuous profiles of electromagnetic wave velocity and water content in glaciers: an example from Bench Glacier, Alaska, USA
Authors: Bradford John H. , Nichols Joshua , Mikesell T. Dylan , Harper Joel T. 
Published: August 2009

AbstractWe conducted two-dimensional continuous multi-offset georadar surveys on Bench Glacier, south-central Alaska, USA, to measure the distribution of englacial water. We acquired data with a multichannel 25 MHz radar system using transmitter–receiver offsets ranging from 5 to 150 m. We towed the radar system at 5–10 kmh–1 with a snow machine with transmitter/receiver positions established by geodetic-grade kinematic differentially corrected GPS (nominal 0.5 m trace spacing). For radar velocity analyses, we employed reflection tomography in the pre-stack depth-migrated domain to attain an estimated 2% velocity uncertainty when averaged over three to five wavelengths. We estimated water content from the velocity structure using the complex refractive index method equation and use a three-phase model (ice, water, air) that accounts for compression of air bubbles as a function of depth. Our analysis produced laterally continuous profiles of glacier water content over several kilometers. These profiles show a laterally variable, stratified velocity structure with a low-water-content (~0–0.5%) shallow layer (~20–30 m) underlain by high-water-content (1–2.5%) ice.