bluuebunny/crossref_metadata_2025 huggingface dataset:
Conceptualizing Cognitive Skills Developed during Video Game Play: A Case Study in Teaching Composition
Authors: Smith Sandra Wilson
Published: August 2008

While video games have been much maligned in the popular press, a number of scholars have begun to explore the positive side of these games, especially in terms of learning. Some critics have analyzed video games and the act of game play as complex, cultural texts. In college courses, such as composition, in which one goal is the development of rhetorical skills like analysis, video games and game play can be used as texts that are both accessible to students and rich in meaningful information. In this article, the author presents a case study of a composition course she developed using the book Everything Bad is Good for You, in which Steven Johnson focuses on popular media, such as video games. Through exposure to Johnson's complex discussion and by drawing on their own experience and observations, students were able to think and write critically about abstract concepts and produce their own meaningful analyses.
Gameplay, Gender, and Socioeconomic Status in Two American High Schools
Authors: Andrews Gillian ‘Gus’
Published: August 2008

In a study of 195 high school students, differences by gender and socioeconomic status (SES) were found in their gaming habits and game literacy practices. Low-SES students generally preferred console video games, particularly those in the sports genre. They expressed frustration with the controls involved in long-form computer games such as those in the role-playing and first-person-shooter genres. Girls overwhelmingly rejected being identified as gamers, though they actively engaged in playing casual games in isolation. Very few students in any demographic group were found to participate in the game literacy practices described by Steinkuehler, and high-SES males were most likely to engage in these practices. These findings suggest cautious further research when generalizing from recommendations of how to harness games for education, such as those presented by Gee. Also, it appears that more attention to sports-themed digital games is warranted, particularly for those interested in reaching low-SES populations, as both boys and girls at the low-SES school played these games.
Empirical Tests of Audit Budget Dynamics
Authors: Ettredge Michael L. , Bedard Jean C. , Johnstone Karla M.
Published: August 2008

Previous research in nonaudit contexts suggests that managers design budgets based on prior performance relative to budget targets, and that this “ratcheting” response can be asymmetrical (i.e., greater increase in target following good performance than the decrease in target following correspondingly bad performance). This implies a dynamic view of budgeting, in which the budget is an endogenous feature of the business environment, a perspective that is rare in the auditing literature. We hypothesize and find asymmetric budget ratcheting by audit firm supervisors in a sample of audit engagements. Further, we find that engagement teams' reported hours also vary asymmetrically with prior budget variance. Our results suggest temporal interdependence between audit firm supervisors and engagement teams as both parties act strategically to adapt budgeting and reporting behavior based on prior budget variances, with associated implications for audit quality.
An Investigation of the Relation between Tax Professionals, Tax Refunds, and Fees
Authors: Hatfield Richard C. , Jackson Scott B. , Schafer Jennifer Kahle
Published: August 2008

Taxpayers in the United States are frequently advised to avoid overpaying their interim taxes. This study seeks to illuminate an underlying cause of tax refunds and a wealth-related consequence that tax refunds may engender due to the employment of a tax professional. Results indicate that tax professionals advise taxpayers to make larger quarterly estimated tax payments when they believe that tax refunds positively influence taxpayers' willingness to pay higher tax return preparation fees. In addition, results indicate that tax professionals bill taxpayers for larger fractions of billable fees when taxpayers receive tax refunds than when they owe the IRS additional taxes, holding the tax liability and other factors constant. These results suggest that taxpayers should be cautious about using their tax position as a heuristic to evaluate the performance of tax professionals, and that the overall cost to taxpayers of receiving tax refunds may be considerably higher than is commonly believed.
Performance Variability, Ambiguity Intolerance, and Balanced Scorecard-Based Performance Assessments
Authors: Liedtka Stephen L. , Church Bryan K. , Ray Manash R.
Published: August 2008

This study extends prior research on general Balanced Scorecard (BSC) evaluation tendencies (e.g., Lipe and Salterio 2000; Ittner et al. 2003; Banker et al. 2004) by documenting that patterns in BSC evaluations vary with a quality of the evaluator. Specifically, using data from an experimental performance assessment exercise, we find that evaluators' “ambiguity intolerance” (Budner 1962) influences their reaction to variation among performance measures within a BSC category. Further, we find that increased variation within a BSC category causes ambiguity-intolerant evaluators to give lower performance evaluation scores when the BSC category indicates relatively strong performance, but has no significant effect when the BSC category indicates relatively weak performance. These results are consistent with the argument that ambiguity-intolerant individuals are more likely to discount or ignore ambiguous information when the ambiguity relates to positive information. Our findings have significant practical implications regarding the accuracy and consistency of BSC evaluations.
The Effects of Moral Reasoning on Financial Reporting Decisions in a Post Sarbanes-Oxley Environment
Authors: Maroney James J. , McDevitt Roselie E.
Published: August 2008

Our study examines whether the certification requirements under Section 302 of the Sarbanes-Oxley Act of 2002 affect financial reporting decisions. Using 74 part-time MBA students as a proxy for corporate managers, we find that the participants' level of moral reasoning and their assessed influence of the Sarbanes-Oxley Act were significantly positively associated with the amount of loss recognized through their financial statement adjustment decisions. Consistent with expectations, there was also a significant interaction whereby the influence of the Sarbanes-Oxley Act was significantly positively associated with the adjustment decision for those participants at lower levels of moral reasoning, but not with the adjustment decision for those participants at higher levels. Thus, the findings from our study suggest that the Sarbanes-Oxley Act may be an effective deterrent for an overstatement of financial statement income by individuals at lower levels of moral reasoning. These results should be of considerable interest to regulators as they attempt to assess the effects of the Sarbanes-Oxley Act.
Trends in Accounting Student Characteristics: Results from a 15-Year Longitudinal Study at FSA Schools
Authors: Nelson Irvin T. , Vendrzyk Valaria P. , Quirin Jeffrey J. , Kovar Stacy E.
Published: August 2008

This article updates the results from a continuing longitudinal study of characteristics of accounting students, sponsored by the Federation of Schools of Accountancy (FSA) since 1991. Specifically, it reports trends in student characteristics between 2000 and 2006 and discusses their implications to the accounting profession and to accounting education. Measures of student quality continue to rise. The percentage of minority students in undergraduate accounting programs increased; however, no similar increase occurred at the graduate level. There was a drop in the percentage of female students in graduate programs. More students are deciding to major in accounting later in their academic careers, with fewer making the decision in high school and more deciding during their sophomore years of college. Job availability is increasingly the most influential factor in students' decisions to major in accounting. Fewer students are taking the GMAT exam, and fewer master's students are joining Beta Alpha Psi. More students are completing internships. Although more are pursuing graduate education, fewer are planning on M.B.A. or Ph.D. degrees. Interest in careers in public accounting is high and increasing, while interest in industry is dropping.
An Experimental Study of Accounting Majors' Academic Achievement Using Cooperative Learning Groups
Authors: Gabbin Alexander L. , Wood Lynette I.
Published: August 2008

This study replicates the work of Hite (1996) by examining the exam re-take cooperative learning strategy. During one semester of an Intermediate Accounting II course, 68 accounting majors took exams in two-and-one-half hour night testing sessions. Students in the treatment groups took group exams immediately after individual exams, while students in the control groups left the testing site after individual exams. The results show that neither the comprehensive final nor the cumulative individual exam scores were significantly different between the treatment and control groups. Contrary to Hite's (1996) findings, this study refutes the assertion that the exam re-take cooperative learning strategy promotes accounting majors' academic achievement.
Exploring Millennial Student Values and Societal Trends: Accounting Course Selection Preferences
Authors: Milliron Valerie C.
Published: August 2008

The values that younger (Millennial) versus older (non-Millennial) students express in choosing a class are contrasted with the skills and attitudes they need to compete. The first half of the paper reviews current literature regarding Millennial student expectations, skill competitiveness, and work opportunities. This is followed by examining priorities on class section selection as a vehicle for investigating student values. The source of this data is an undergraduate state university business program populated by middle class, mostly white students. Survey data from 275 students in accounting classes is analyzed to ascertain the importance attached to 14 class attributes. The overall results suggest that instructors face a major motivational challenge. Student ratings indicate relatively low importance is attached to developing skills associated with professional success. The Millennial student response appears even further out of alignment with global labor market reality by placing a significantly higher value on low workload and less importance on analytical and computational assignments.
Detecting Spreadsheet Errors: An Education Case
Authors: Janvrin Diane J.
Published: August 2008

In the past two decades, computing applications developed by non-system professionals have increased dramatically throughout the professional accounting and business community. Unfortunately, prior research indicates that many end-user computing applications such as spreadsheets contain difficult-to-detect errors. Relying on these error-prone applications, professionals may make inappropriate decisions that can negatively impact financial results. This case enhances students' understanding of end-user computing risk by illustrating the difficulty of detecting errors in spreadsheets. Furthermore, this case helps students improve their ability to detect spreadsheet errors.
Bak Funeral Home
Authors: Ruhl Jack M. , Wilson Larry
Published: August 2008

Bak Funeral Home is based on a real situation occurring at a family-owned funeral home in the northern United States. Following the founder's death, his family must decide what to do with the business and tangible assets. Students assume the role of a CPA called upon to advise the client on how to pass the business to the next generation. They encounter an ambiguous situation in which both monetary and nonmonetary factors must be carefully considered. The case is suitable for use in: an undergraduate cost accounting course; an entrepreneurial course in family business issues; or an introductory cost accounting class at the M.B.A. level. Additional topics covered include: the pro forma cash flow statement; business valuation; cash flow return on investment; and business risk.
Absence of electroencephalographic seizure activity in patients treated for head injury with an intracranial pressure–targeted therapy
Authors: Olivecrona Magnus , Zetterlund Bo , Rodling-Wahlström Marie , Naredi Silvana , Koskinen Lars-Owe D.
Published: August 2008

Object

The authors prospectively studied the occurrence of clinical and nonclinical electroencephalographically verified seizures during treatment with an intracranial pressure (ICP)–targeted protocol in patients with traumatic brain injury (TBI).

Methods

All patients treated for TBI at the Department of Neurosurgery, University Hospital Umeå, Sweden, were eligible for the study. The inclusion was consecutive and based on the availability of the electroencephalographic (EEG) monitoring equipment. Patients were included irrespective of pupil size, pupil reaction, or level of consciousness as long as their first measured cerebral perfusion pressure was > 10 mm Hg. The patients were treated in a protocol-guided manner with an ICP-targeted treatment based on the Lund concept. The patients were continuously sedated with midazolam, fentanyl, propofol, or thiopental, or combinations thereof. Five-lead continuous EEG monitoring was performed with the electrodes at F3, F4, P3, P4, and a midline reference. Sensitivity was set at 100 μV per cm and filter settings 0.5–70 Hz. Amplitude-integrated EEG recording and relative band power trends were displayed. The trends were analyzed offline by trained clinical neurophysiologists.

Results

Forty-seven patients (mean age 40 years) were studied. Their median Glasgow Coma Scale score at the time of sedation and intubation was 6 (range 3–15). In 8.5% of the patients clinical seizures were observed before sedation and intubation. Continuous EEG monitoring was performed for a total of 7334 hours. During this time neither EEG nor clinical seizures were observed.

Conclusions

Our protocol-guided ICP targeted treatment seems to protect patients with severe TBI from clinical and subclinical seizures and thus reduces the risk of secondary brain injury.
WingSpan Stent System in the endovascular treatment of intracranial aneurysms: clinical experience with midterm follow-up results
Authors: Yavuz Kivilcim , Geyik Serdar , Saatci Isil , Cekirge H. Saruhan
Published: August 2008

Object

The WingSpan stent is a new self-expandable neurovascular stent designed for endovascular treatment of intracranial atheromatous lesions. The authors report their experience with the use of this stent for the endovascular treatment of intracranial aneurysms.

Methods

Thirty-seven patients with 40 wide-necked intracranial aneurysms were treated using the WingSpan stent. Twenty-two aneurysms (55%) were small and 18 (45%) were large or giant. In all but 4 aneurysms, embolization was completed by packing the aneurysm sac with platinum coils. In 4 dissecting aneurysms that were fusiform or too small and wide necked to be catheterized, the stent was used alone. In these cases, the stent bridged the aneurysm neck to allow for flow redirection and the potential stent-induced endothelization effect.

Results

Follow-up angiograms obtained in 3 of 4 aneurysms, treated with only stent placement, demonstrated aneurysmal thrombosis and parent artery remodeling in 2 patients and moderate decrease in size in 1. Follow-up angiography obtained at 6 months to 1 year in 31 aneurysms after stent-supported coil embolization demonstrated complete occlusion in 23 aneurysms (74.2%) with a progressive thrombosis rate of 66.7% (10 of 15 aneurysms), and a recanalization rate of 16.1%.

Conclusions

In treating wide-necked intracranial aneurysms, the WingSpan Stent System is very flexible, secure, and effective. Its delivery system is very easy and exact in that it exerts higher outward radial force, thus providing an excellent conformability and a strong scaffold to hold the coils in place. It may offer an effective treatment when used alone in some fusiform or very wide-necked, small dissecting aneurysms in which other surgical or endovascular treatment strategies are not deemed feasible.
Results using a self-expanding stent alone in the treatment of severe symptomatic carotid bifurcation stenosis
Authors: Bussière Miguel , Pelz David M. , Kalapos Paul , Lee Donald , Gulka Irene , Leung Andrew , Lownie Stephen P.
Published: August 2008

Object

Conventional endovascular therapy for carotid stenosis involves placement of an embolic protection device followed by stent insertion and angioplasty. A simpler approach may be placement of a stent alone. The authors determined how often this approach could be used to treat patients with carotid stenosis, and assessed which factors would preclude this approach.

Methods

Over a period of 6 years, 97 patients with symptomatic carotid stenosis were treated with the intention of using a “stent-only” approach. Arteries in 77 patients (79%) were treated with stents alone, 13 required preinsertion balloon dilation, 6 postinsertion dilation, and 1 both pre- and postinsertion dilation.

Results

The mean stenosis according to North American Symptomatic Carotid Endarterectomy Trial criteria was reduced from 82 to 40% in the stent-only group and from 89 to 37% in the stent and balloon angioplasty group. The 30-day stroke and death rate was 7.2%. Patients were followed for a mean of 15 months. In the stent-alone group, the mean preoperative Doppler peak systolic velocity (PSV) was 409 cm/second, with an internal carotid artery/common carotid artery (ICA/CCA) ratio of 7.2. At follow-up review, the PSV decreased to 153 cm/second and the ICA/CCA ratio to 2.1. In the angioplasty group the mean preoperative PSV was 496 cm/second and the ICA/CCA ratio was 9.2, decreasing to 163 cm/second and 2, respectfully, at follow-up evaluation. Restenosis occurred in 12.8% of patients at 6 months and in 15.9% at 1 year. One stroke occurred during the follow-up period in each group. Using multivariable analysis, factors precluding the “stent-only” approach were as follows: severity of stenosis, circumferential calcification, and no history of hyperlipidemia.

Conclusions

Balloons may not be required to treat all patients with carotid stenosis. A stent alone was feasible in 79% of patients, and 79% of patients were alive and free from ipsilateral stroke or restenosis at 1 year. Restenosis rates with this approach are higher than with conventional angioplasty and stent insertion. Carotid arteries with very severe stenoses (> 90%) and circumferential calcification may be more successfully treated with angioplasty combined with stent placement.
Intraoperative subcortical stimulation mapping of language pathways in a consecutive series of 115 patients with Grade II glioma in the left dominant hemisphere
Authors: Duffau Hugues , Gatignol Peggy , Mandonnet Emmanuel , Capelle Laurent , Taillandier Luc
Published: August 2008

Object

Despite better knowledge of cortical language organization, its subcortical anatomofunctional connectivity remains poorly understood. The authors used intraoperative subcortical stimulation in awake patients undergoing operation for a glioma in the left dominant hemisphere to map the language pathways and to determine the contribution of such a method to surgical results.

Methods

One hundred fifteen patients harboring a World Health Organization Grade II glioma within language areas underwent operation after induction of local anesthesia, using direct electrical stimulation to perform online cortical and subcortical language mapping throughout the resection.

Results

After detection of cortical language sites, the authors identified 1 or several of the following subcortical language pathways in all patients: 1) arcuate fasciculus, eliciting phonemic paraphasia when stimulated; 2) inferior frontooccipital fasciculus, generating semantic paraphasia when stimulated; 3) subcallosal fasciculus, inducing transcortical motor aphasia during stimulation; 4) frontoparietal phonological loop, eliciting speech apraxia during stimulation; and 5) fibers coming from the ventral premotor cortex, inducing anarthria when stimulated. These structures were preserved, representing the limits of the resection. Despite a transient immediate postoperative worsening, all but 2 patients (98%) returned to baseline or better. On control MR imaging, 83% of resections were total or subtotal.

Conclusions

These results represent the largest experience with human subcortical language mapping ever reported. The use of intraoperative cortical and subcortical stimulation gives a unique opportunity to perform an accurate and reliable real-time anatomofunctional study of language connectivity. Such knowledge of the individual organization of language networks enables practitioners to optimize the benefit-to-risk ratio of surgery for Grade II glioma within the left dominant hemisphere.
Surgical management and outcome of large orbitocranial osteomas
Authors: Secer Halil Ibrahim , Gonul Engin , Izci Yusuf
Published: August 2008

Object

The goal of this study is to review the surgical management and outcome of patients who were treated for large orbitocranial osteomas at Gulhane Military Medical Academy over a period of 7 years.

Methods

Twenty-one patients with large orbitocranial osteomas were evaluated retrospectively. All patients were male and between 19 and 25 years old. Surgery was performed in all patients. The main surgical procedure was resection of the osteoma using orbitotomy and/or craniotomy followed by orbital reconstruction and cranioplasty. Cranioplasty was performed in 16 patients, using methyl methacrylate in 5 patients (31%) and porous polyethylene in 11 patients (69%). Thin, flexible, porous polyethylene was preferred for orbital reconstruction in 10 patients. The cranioplasty materials were attached to the intact bone using miniplates.

Results

There were no severe postoperative complications. Mild transient periorbital ecchymosis was noted in 19 patients. The mean follow-up period was 11.7 months (range 9–24 months) after surgery. No tumor regrowth was observed in any patient at the end of the follow-up period.

Conclusions

Large osteomas of the orbitocranial region must be resected for cosmetic and functional reasons. Selection and planning of the surgical technique should be based on the direction of the tumor growth and on the size of the tumor and the structures that are compressed by the tumor.
Ruptured distal middle cerebral artery aneurysm filled with tumor cells in a patient with intravascular large B-cell lymphoma
Authors: Anda Takeo , Haraguchi Wataru , Miyazato Hajime , Tanaka Shinsuke , Ishihara Tokuhiro , Aozasa Katsuyuki , Nakamichi Itsuko
Published: August 2008

The authors describe a very rare case of intravascular large B-cell lymphoma in a woman whose ruptured distal middle cerebral artery (MCA) aneurysms were filled with lymphoma cells. A 69-year-old woman who had undergone artificial graft replacement for an aortic aneurysm presented with transient left hemiparesis. Magnetic resonance imaging demonstrated a small fresh cerebral infarction in the right frontal lobe, although major cervical and cerebral arteries were shown to be intact on MR angiography. Antiplatelet and anticoagulation treatments commenced. On the 21st day after onset, the patient suffered a subarachnoid hemorrhage, and a digital subtraction angiogram revealed aneurysmal lesions in the distal MCA. Based on the histological examination of the resected aneurysms, proliferation of large B-cell lymphoma was identified in the dilated arterial lumen. On the 71st day after ischemic onset, intracranial hemorrhage recurred, and she died. Postmortem examination revealed similar lymphoma cells only in the intimal layer that had grown on the artificial graft, and it was decided that the patient had had intravascular large B-cell lymphoma. The preceding cerebral infarction was thought to be due to occlusion of the distal MCA by tumor embolus, which may be the initial pathological stage in aneurysm formation. For patients with incomprehensible ischemic cerebral stroke, neoplasm must be taken in consideration.
Intracranial pial single-channel arteriovenous fistula presenting with significant brain edema
Authors: Masuoka Jun , Sakata Shuji , Maeda Kenji , Matsushima Toshio
Published: August 2008

The authors report a rare case of pial single-channel arteriovenous fistula presenting with significant brain edema. A 51-year-old woman was admitted with a 5-day history of headache and nausea, followed by consciousness disturbance. Computed tomography showed cerebellar swelling with obstructive hydrocephalus. Magnetic resonance imaging revealed extensive vasogenic edema in the cerebellum bilaterally. Angiography demonstrated 2 different arteriovenous shunts (AVSs) at peripheral branches of the right anterior inferior cerebellar artery. One was located on the suboccipital surface. It drained through a dilated inferior vermian vein and emptied retrogradely into the contralateral cerebellar veins with marked stagnation. Focal stenosis of the dilated draining vein was present. The other AVS was located on the petrosal surface, which had a slow flow with no angiographic evidence of venous congestion. Given that the latter was believed to be asymptomatic, the former AVS was excised, and histological examination revealed that the lesion consisted of a direct communication of multiple arterial feeding vessels with a single vein, consistent with a diagnosis of pial single-channel arteriovenous fistula. The restriction of venous drainage presumably caused venous hypertension, leading to the brain edema and neurological symptoms.
Reduction of ischemic brain injury in rats with normothermic and hyperthermic conditions
Authors: Shabanzadeh Alireza P. , Shuaib Ashfaq , Wang Chen Xu
Published: August 2008

Object

Statins have been used for induction of ischemic tolerance after cerebral ischemia. The authors have previously shown that simvastatin is protective after ischemic cerebral injury in normothermic conditions. In this study they further examined whether treatment with simvastatin can reduce ischemic brain injury in a hyperthermic condition.

Methods

Focal ischemic brain injury was induced by embolizing a preformed clot into the middle cerebral artery in rats. The authors initially examined whether treatment with simvastatin could reduce ischemic brain injury without or with hyperthermia. The infarct volume, edema, and neurological deficits were examined. They then studied whether simvastatin could reduce the perfusion deficits, damage to the blood–brain barrier (BBB), and degeneration of neurons in the ischemic injured brain.

Results

Simvastatin significantly reduced the infarct volume in both normothermic and hyperthermic conditions, compared with appropriate controls. Concomitantly, this treatment also significantly reduced neurological deficits and brain edema. Administration of simvastatin significantly decreased perfusion deficits, BBB permeability, and degenerated neurons.

Conclusions

These studies suggest that simvastatin is an effective agent for ischemic brain injury not only in normothermic but also in hyperthermic conditions, which may be through the decrease of BBB permeability, degenerated neurons, and perfusion deficits.
Proteomic characterization of primary diffuse large B-cell lymphomas in the central nervous system
Authors: Li Jie , Okamoto Hiroaki , Yin Chunyue , Jagannathan Jay , Takizawa Jun , Aoki Sadao , Gläsker Sven , Rushing Elisabeth J. , Vortmeyer Alexander O. , Oldfield Edward H. , Yamanaka Ryuya , Zhuang Zhengping
Published: August 2008

Object

The lack of primary lymphoid tissue within the central nervous system (CNS) confounds our understanding of the pathogenesis of primary CNS lymphomas (PCNSLs). Comparing the protein expression of PCNSLs and sporadic systemic lymphomas (SSLs) provides a useful strategy for identifying a molecular signature that characterizes disease-associated features and provides information regarding tumor initiation and progression.

Methods

Seven diffuse large B-cell PCNSLs were selected to undergo 2D gel electrophoresis, and profiled proteomes from these PCNSLs were compared with those from 7 diffuse large B-cell SSLs. Distinguishing proteins were sequenced using mass spectrometry.

Results

Two-dimensional gel electrophoresis identified an average of 706 proteins from each specimen. Computerized gel analysis and manual reconfirmation revealed a 96% similarity in the proteomes of PCNSLs and SSLs. Comparative analysis identified 9 proteins significantly overexpressed (p < 0.05) and 16 proteins downregulated in PCNSLs. The proteomic findings were further validated using Western blot and immunohistochemical staining.

Conclusions

The similarities in proteomic patterns between PCNSLs and SSLs suggest that these tumor types share structural similarities, acquired during differentiation. The ultimate fate of lymphomatous cells (CNS vs systemic) may be related to differentially expressed proteins, which function in homing and host processing. Elucidating the roles of these differentially expressed proteins will prove valuable in understanding the pathogenesis of PCNSL.
Effect of ependymal and pial surfaces on convectionenhanced delivery
Authors: Jagannathan Jay , Walbridge Stuart , Butman John A. , Oldfield Edward H. , Lonser Russell R.
Published: August 2008

Object

Convection-enhanced delivery (CED) is increasingly used to investigate new treatments for central nervous system disorders. Although the properties of CED are well established in normal gray and white matter central nervous system structures, the effects on drug distribution imposed by ependymal and pial surfaces are not precisely defined. To determine the effect of these anatomical boundaries on CED, the authors infused low MW and high MW tracers for MR imaging near ependymal (periventricular) and pial (pericisternal) surfaces.

Methods

Five primates underwent CED of Gd-diethylenetriamine pentaacetic acid (Gd-DTPA; MW 590 D) or Gd-bound albumin (Gd-albumin; MW 72,000 D) during serial real-time MR imaging (FLAIR and T1-weighted sequences). Periventricular (caudate) infusions were performed unilaterally in 1 animal (volume of infusion [Vi] 57 μl) and bilaterally in 1 animal with Gd-DTPA (Vi = 40 μl on each side), and bilaterally in 1 animal with Gd-albumin (Vi = 80 μl on each side). Pericisternal infusions were performed in 2 animals with Gd-DTPA (Vi = 190 μl) or with Gd-albumin (Vi = 185 μl) (1 animal each). Clinical effects, MR imaging, and histology were analyzed.

Results

Large regions of the brain and brainstem were perfused with both tracers. Intraparenchymal distribution was successfully tracked in real time by using T1-weighted MR imaging. During infusion, the volume of distribution (Vd) increased linearly (R2 = 0.98) with periventricular (mean Vd/Vi ratio ± standard deviation; 4.5 ± 0.5) and pericisternal (5.2 ± 0.3) Vi, but did so only until the leading edge of distribution reached the ependymal or pial surfaces, respectively. After the infusate reached either surface, the Vd/Vi decreased significantly (ependyma 2.9 ± 0.8, pia mater 3.6 ± 1.0; p < 0.05) and infusate entry into the ventricular or cisternal cerebrospinal fluid (CSF) was identified on FLAIR but not on T1-weighted MR images.

Conclusions

Ependymal and pial boundaries are permeable to small and large molecules delivered interstitially by convection. Once infusate reaches these surfaces, a portion enters the adjacent ventricular or cisternal CSF and the tissue Vd/Vi ratio decreases. Although T1-weighted MR imaging is best for tracking intraparenchymal infusate distribution, FLAIR MR imaging is the most sensitive and accurate for detecting entry of Gd-labeled imaging compounds into CSF during CED.
Automated, compliant, high-flow common carotid to middle cerebral artery bypass
Authors: Dacey Ralph G. , Zipfel Gregory J. , Ashley William W. , Chicoine Michael R. , Reinert Michael
Published: August 2008

The authors describe the use of the Cardica C-Port xA Distal Anastomosis System to perform an automated, high-flow extracranial–intracranial bypass. The C-Port system has been developed and tested in coronary artery bypass surgery for rapid distal coronary artery anastomoses. Air-powered, it performs an automated end-to-side anastomosis within seconds by nearly simultaneously making an arteriotomy and inserting 13 microclips into the graft and recipient vessel. Intracranial use of the device was first simulated in a cadaver prepared for microsurgical anatomical dissection.

The authors used this system in a 43-year-old man who sustained a subarachnoid hemorrhage after being assaulted and was found to have a traumatic pseudoaneurysm of the proximal intracranial internal carotid artery. The aneurysm appeared to be enlarging on serial imaging studies and it was anticipated that a bypass would probably be needed to treat the lesion. An end-to-side bypass was performed with the C-Port system using a saphenous vein conduit extending from the common carotid artery to the middle cerebral artery. The bypass was demonstrated to be patent on intraoperative and postoperative arteriography. The patient had a temporary hyperperfusion syndrome and subsequently made a good neurological recovery.

The C-Port system facilitates the performance of a high-flow extracranial–intracranial bypass with short periods of temporary arterial occlusion. Because of the size and configuration of the device, its use is not feasible in all anatomical situations that require a high-flow bypass; however it is a useful addition to the armamentarium of the neurovascular surgeon.
Treatment of pediatric intracranial vascular malformations using Onyx-18
Authors: Jankowitz Brian T. , Vora Nirav , Jovin Tudor , Horowitz Michael
Published: August 2008

Object

Onyx-18 is a relatively new liquid embolic agent. The initial success with this polymer will result in increased utilization in children, but its use and safety in the pediatric population have not been firmly established.

Methods

Between December 2005 and January 2008, the cerebral vascular malformations in 6 children were embolized using Onyx-18. The ages of the patients ranged from 1 day to 12 years. Pathological types of the vascular malformations included 4 arteriovenous malformations and 2 vein of Galen malformations. Clinical presentations included intracranial hemorrhage in 2 patients, papilledema in 1 patient, and high-output heart failure in 3 patients.

Results

In 6 pediatric patients, 21 embolization procedures were performed utilizing a combination of Onyx-18, platinum coils, and Embosphere microspheres. The average estimated size reduction for the arteriovenous malformations was 60%. Total obliteration of a malformation was achieved in 1 patient. Two patients received adjuvant radiosurgery. Of the 2 vein of Galen malformations, one was completely embolized and the other had an ~ 50% reduction in flow. No open surgical intervention was used. Clinical follow-up ranged from 7 to 12 months. Angiographic follow-up data were obtained at 1, 6, and 7 months in 3 patients, whereas 1 patient awaits repeat angiography. Complications included a transient monoparesis with complete resolution in 1 patient. Two patients died within 24 hours of an embolization procedure due to intracranial hemorrhages.

Conclusions

Onyx-18 is a feasible embolization agent for use in intracranial vascular malformations in the pediatric population, but long-term follow-up data will be necessary to assess the continued efficacy and safety of this agent.
Postnatal ascent of the cerebellar tonsils in Chiari malformation Type II following surgical repair of myelomeningocele
Authors: Morota Nobuhito , Ihara Satoshi
Published: August 2008

Object

Postnatal improvement in Chiari malformation type II (CM-II) following surgical repair of myelomeningocele was evaluated.

Methods

The authors reviewed data obtained in 20 cases in which patients underwent postnatal myelomeningocele repair within the first 48 hours after birth between October 2002 and September 2006. In 14 patients (Group 1), myelomeningocele was diagnosed in utero and the infants were delivered by cesarean section at 35–39 weeks' gestation (mean 36.4). The 6 infants in Group 2 were born after full-term gestation (39–41 weeks), and their myelomeningoceles were diagnosed postnatally. In all 20 patients, the myelomeningoceles were surgically repaired postnatally. Dynamic change of the herniated cerebellar tonsils in CM-II before and after the myelomeningocele repair, associated hydrocephalus, and symptomatic CM-II were analyzed.

Results

In Group 1, the CM-II was confirmed before myelomeningocele repair in 13 cases (93%). The spinal level of the caudal end of the cerebellar tonsils ranged from C-2 to C-7. Ascent of the cerebellar tonsils was observed in 11 patients (range 1–4 spinal levels, mean 2 levels) and continued even after ventriculoperitoneal (VP) shunt placement in most patients. A VP shunt was required for the treatment of hydrocephalus in 12 patients (86%). Symptomatic CM-II developed in 8 of 13 patients (61%), 3 of whom required surgical decompression.

In Group 2, CM-II was confirmed in 5 infants (83%), with the cerebellar tonsils at a spinal level of C-2 to C-4 or C-5. Ascent of the cerebellar tonsils was observed in 4 patients (range 1–1.5 spinal levels, average 1.1 levels), and no patient had symptomatic CM-II. A VP shunt was placed in 5 patients (83%). No patient was lost to follow-up during the 18-month follow-up period. The only statistically significant difference between the 2 groups was the presence of symptomatic CM-II in Group 2 (p = 0.02).

Conclusions

Patients showed ascent of the cerebellar tonsils after postnatal myelomeningocele repair. Placement of a VP shunt helped promote the ascent. However, postnatal myelomeningocele repair in the patients in Group 1 failed to consistently prevent development of symptomatic CM-II. This limited experience suggests that postnatal repair of myelomeningocele can partially reverse the anatomical CM-II, but symptomatic CM-II cannot be prevented in some patients when the repair is performed after 36 weeks' gestation.
The Dandy–Walker variant: a case series of 24 pediatric patients and evaluation of associated anomalies, incidence of hydrocephalus, and developmental outcomes
Authors: Sasaki-Adams Deanna , Elbabaa Samer K. , Jewells Valerie , Carter Lori , Campbell Jeffrey W. , Ritter Ann M.
Published: August 2008

Object

The Dandy–Walker complex is a continuum of aberrant development of the posterior fossa that has been associated with multiple congenital anomalies, radiographic abnormalities, and developmental delay. The Dandy–Walker variant (DWV) is a unique entity believed to represent a milder form of the complex, and is characterized by a specific constellation of radiographic findings. In this retrospective case series, the authors report the association of the DWV with other congenital anomalies, the associated radiographic findings linked with DWV, and the developmental outcome in this population.

Methods

The charts and radiographs of 10 male and 14 female patients treated between 2000 and 2006 were examined. The patients' mean gestational age was 35.6 weeks (range 23–41 weeks), and the mean follow-up period was 5.1 years (range 1 month–15 years).

Results

Three patients died. Associated anomalies included cardiac (41.7%), neurological (33.3%), gastrointestinal (20.8%), orthopedic (12.5%), and genitourinary (12.5%) abnormalities. Less common were pulmonary and psychiatric findings. Developmental delay was identified in 11 of the 21 patients for whom follow-up was available. Five of 6 patients with isolated DWV had a normal developmental course. Radiographic findings associated with DWV included corpus callosum dysgenesis in 20.8%, ventricular enlargement in 29%, and vermian rotation in 8.3%. Shunts were placed in 4 of 7 patients with ventriculomegaly. Using the two-tailed Pearson correlation, the authors determined that developmental outcome was solely affected by neurological deficits and that ventricular enlargement predicted the need for shunt placement.

Conclusions

The DWV was associated with both extra- and intracranial anomalies. Associated radiographic abnormalities including ventriculomegaly were observed. Hydrocephalus requiring cerebrospinal fluid diversion may be indicated. Isolated DWV was associated with a good developmental outcome.
Ossified pseudomeningocele following Chiari decompression surgery in a patient with Kleeblattschädel deformity
Authors: Reynolds Matthew R. , Blackburn Spiros L. , Smyth Matthew D.
Published: August 2008

The authors present the case of a 3-year-old child with Kleeblattschädel, or cloverleaf skull deformity, and a Chiari malformation Type I who developed an ossified pseudomeningocele after posterior fossa decompression. To their knowledge, this is the first report of a postoperative ossified pseudomeningocele in a patient with Kleeblattschädel and the only case of an ossified pseudomeningocele located outside the lumbosacral region. A genetic basis for the ossification process seems likely given the child's history of premature cranial suture closure. The authors draw attention to this rare complication and review the available body of literature on this topic.
Primary primitive neuroectodermal tumor of the lumbar extradural space
Authors: Ozdemir Nail , Usta Gungor , Minoglu Mustafa , Erbay Ayse Mecit , Bezircioglu Hamdi , Tunakan Mine
Published: August 2008

Primary spinal primitive neuroectodermal tumors (PNETs) of the extradural space are very rare; only 10 cases have been reported in the English language literature. The histopathological diagnosis of primary spinal PNETs has been discussed for many years. These tumors have a rapidly progressive course, and there is no current consensus on the optimal therapeutic approach for these patients. The authors present a case of primary PNET located in the lumbar extradural space in a 13-year-old girl and report the clinical, radiological, histopathological, and surgical findings. They compare their findings with those from the other 10 cases reported in the literature and review relevant literature.
CFU‐MK Assay for Acute Thrombocytopenia
Authors: Parent‐Massin Dominique , Sibiril Yann
Published: August 2008

In this unit, protocols to culture human platelet progenitors (Colony Forming Unit–Megakaryocyte; CFU‐M) with or without toxicants are described. Platelet progenitors are obtained from human umbilical cord blood. After separation of mononuclear cells, the cell suspension can be cryopreserved or plated immediately. Megakaryocytes are identified by immunocytochemistry. Test chemicals are added to the culture medium before cells are plated. Megakaryocytes are scored after 12 days of culture. IC10, IC50 and IC90 can be calculated by comparison to control cultures. A predictive model is proposed to evaluate the hazard of thrombocytopenia induced by chemicals. When IC50 and IC90 are below Cmax in humans, the likelihood of thrombocytopenia is strong. Curr. Protoc. Toxicol. 37:20.5.1‐20.5.14. © 2008 by John Wiley & Sons, Inc.
The Use of Detergents to Purify Membrane Proteins
Authors: Arnold Thomas , Linke Dirk
Published: August 2008

Extraction of membrane proteins from biological membranes is usually accomplished with the help of detergents. This unit describes the use of detergents to solubilize and purify membrane proteins. The chemical and physical properties of the different classes of detergents typically used with biological samples are discussed. A separate section addresses the compatibility of detergents with applications downstream of the membrane protein purification process, such as optical spectroscopy, mass spectrometry, protein crystallography, or biomolecular NMR. Protocols in this unit include the isolation and solubilization of biological membranes, phase separation, and support protocols for detergent removal and detergent exchange using different methods. Curr. Protoc. Protein Sci. 53:4.8.1‐4.8.30. © 2008 by John Wiley & Sons, Inc.
Sample Preparation and In‐Solution Protease Digestion of Proteins for Chromatography‐Based Proteomic Analysis
Authors: Washburn Michael P.
Published: August 2008

The adoption of chromatography‐based proteomics approaches has resulted in the development of new methods for optimal use of these technologies. One such technology, named multidimensional protein identification technology (MudPIT), directly couples liquid chromatography with tandem mass spectrometry. In the MudPIT approach, digested protein samples are directly loaded onto a microcapillary column packed sequentially with reversed‐phase and strong cation exchange resins. Once digested protein samples are loaded onto the column, the column is placed in‐line between a high‐performance liquid chromatography system and an electrospray ionization tandem mass spectrometer (ESI‐MS/MS). The digested protein samples for MudPIT analysis must be directly compatible with ESI‐MS/MS, so the sample preparation and digestion protocols must be optimized for this purpose. The primary objective of all of the protocols in this unit is to yield a final digested protein mixture of less than 300 µl that can then be directly loaded onto a MudPIT column. Curr. Protoc. Protein Sci. 53:23.6.1‐23.6.11. © 2008 by John Wiley & Sons, Inc.
Techniques in Aseptic Rodent Surgery
Authors: Hoogstraten‐Miller Shelley L. , Brown Patricia A.
Published: August 2008

Performing aseptic survival surgery in rodents can be challenging. This unit describes some basic principles to assist clinicians, researchers, and technicians in becoming proficient in performing aseptic rodent surgery. Curr. Protoc. Immunol. 82:1.12.1‐1.12.14. © 2008 by John Wiley & Sons, Inc.
Total Internal Reflection Fluorescence (TIRF) Microscopy
Authors: Trache Andreea , Meininger Gerald A.
Published: August 2008

Total internal reflection fluorescence (TIRF) microscopy represents a method of exciting and visualizing fluorophores present in the near‐membrane region of live or fixed cells grown on coverslips. TIRF microscopy is based on the total internal reflection phenomenon that occurs when light passes from a high‐refractive medium (e.g., glass) into a low‐refractive medium (e.g., cell, water). The evanescent field produced by total internally reflected light excites the fluorescent molecules at the cell‐substrate interface and is accompanied by minimal exposure of the remaining cell volume. This technique provides high‐contrast fluorescence images, with very low background and virtually no out‐of‐focus light, ideal for visualization and spectroscopy of single‐molecule fluorescence near a surface. This unit presents, in a concise manner, the principle of operation, instrument diversity, and TIRF microscopy applications for the study of biological samples.
Genetic Manipulation of Campylobacter jejuni
Authors: Davis Lindsay , Young Kathryn , DiRita Victor
Published: August 2008

Molecular manipulation has been a limiting factor in C. jejuni research for many years. Recent advances in molecular techniques adapted for C. jejuni have furthered our understanding of the organism. This unit is dedicated to common molecular tools in bacterial research specifically tailored for C. jejuni. These include colony PCR, DNA isolation, and RNA isolation. The unit also reviews techniques for genetic manipulation, such as the use of plasmids, natural transformation, electroporation, conjugation, and transposition. In addition, a reporter system, the arylsulfatase assay, can be used to study gene expression.