Measuring social interdependence in collaborative learning: instrument development and validation.

BACKGROUND: In health professions education, several collaborative learning approaches have been used. As collaborative learning has a theoretical background of social interdependence theory, a theory informed and valid instrument to measure social interdependence is required to evaluate and compare several learning approaches. The aim of this study was to develop an instrument (the SOcial interdependence in Collaborative learning Scale; SOCS) to measure students' perceived social interdependence in collaborative learning and validate it. METHODS: We conducted a modified Delphi procedure among stakeholders to develop the content validity of the instrument. To establish construct validity, we performed a confirmatory factor analysis, and we estimated reliability. RESULTS: Two rounds of Delphi were conducted to develop the instrument. Confirmatory factor analysis yielded a three-factor model with 15 items, which provided an excellent fit with CMIN/df = 1.838, GFI = 0.924, CFI = 0.951, RMSEA = 0.061, and PCLOSE = 0.121. Alpha-coefficients for all factors indicated high internal consistency of all the factors. CONCLUSION: This study describes the development and construct validation of the SOCS for measuring social interdependence in collaborative learning. This instrument will provide teachers and schools with feedback about their classroom environment.

Prognostic significance of the immunohistochemical staining of cleaved caspase-3, an activated form of caspase-3, in gliomas.

PURPOSE: Gliomas are common tumors of the central nervous system, and the majority of patients with gliomas have a poor prognosis. The prediction of prognosis is very important in selecting treatment. In the present study, we retrospectively examined the immunohistochemical staining of cleaved caspase-3 (CC3), an activated form of caspase-3 that acts as a lethal protease at the most distal stage of the apoptosis pathway, in gliomas, and the correlation between the prognosis of patients and caspase-3 activation to find useful prognostic indicators. EXPERIMENTAL DESIGN: Immunohistochemical staining of CC3 was done in 65 patients with gliomas. The percentage of CC3 staining-positive cells was defined as the CC3 immunoreactivity score (IRS). Survival analysis between CC3 IRS of glioma patients and survival time was carried out using the Kaplan-Meier method with the log-rank test and the Cox proportional hazards regression model. RESULTS: CC3 IRS was statistically analyzed to designate the best provisional cutoff point, and when detected in >10% of glioma cells, it was considered positive. The Kaplan-Meier method with the log-rank test revealed that patients with CC3 IRS-positive tumors had significantly greater survival than those with CC3 IRS-negative tumors among three grades, 2, 3, and 4 (P = 0.0061), and within grade 3 of anaplastic astrocytoma (P = 0.0458). After adjustment for known clinical prognostic factors, such as age, WHO grade, and performance status, the hazard ratio for CC3 IRS-positive was 0.39 with 95% confidence interval between 0.19 and 0.85 (P = 0.0187). Within high grades, including grades 3 and 4, the hazard ratio was 0.40 with 95% confidence interval between 0.20 and 0.86 (P = 0.0192). CONCLUSIONS: CC3 IRS could be useful as a good prognostic indicator for glioma patients.

Transient cerebellar mutism caused by bilateral damage to the dentate nuclei after the second posterior fossa surgery. Case report.

The authors report on the case of a 6-year-old boy who underwent resection of a midline cerebellar tumor. The boy was able to speak fluently after the operation. Magnetic resonance (MR) imaging showed that the right dentate nucleus had been partially removed along with the tumor, but that the left dentate nucleus remained with the residual tumor. A second operation was performed to remove the residue, after which the child suffered mutism. Three weeks post-surgery, he could only communicate through gestures. He started speaking I week later and regained normal speech 2 months after the operation. Final MR imaging revealed gross-total removal of the tumor and dentate nucleus on the injured left side. The cerebellar mutism was considered to have been caused by bilateral damage to the dentate nuclei and not by unilateral damage.

A container for transporting small laboratory animals for magnetic resonance imaging.

We have constructed a simple container, consisting of a propylene tube, a High-Efficiency Particulate Aerosol (HEPA) filter and a rubber glove, for transporting small animals to magnetic resonance imaging (MRI) facilities that are located outside a pathogen-free environment. Results of pathogens analysis indicate that the container is able to prevent infection by several microorganisms. The quality of the MR images of mice and rats transported in, and imaged while in the container was satisfactory. This container can be useful for examinations that required the use of instruments located outside clean animal units, ensuring safety for both humans and animals.

Diffuse encephaloventriculitis and substantial leukoencephalopathy after intraventricular administration of recombinant adenovirus.

OBJECTIVES: The use of recombinant adenovirus as a vehicle for gene transfer into ependymal cells is a potential therapeutic tool for the treatment of various neural disorders. However, gene transfer into the ependymal cells of the ventricular wall is associated with high-level expression of the transferred gene, which declines rapidly. The purpose of this study is to understand the cause of this early decline in gene expression. METHODS: Different doses of adenovirus-expressing beta-galactosidase (Ad-beta-gal) were injected into the lateral brain ventricle of C57BL/6 mice, and the brains were observed histologically and with magnetic resonance (MR) imaging for a month. RESULTS: Inoculation of the lateral ventricle with more than 1 x 10(8) viral particles (2.6 x 10(6) pfu) resulted in a rapid decline of beta -gal expression. MR imaging indicated gradual ventriculomegaly and histological analysis showed the loss of the ependymal cells from the ventricular wall, lymphocytes infiltration near the wall, degeneration of myelinated fibers and apoptosis in the external capsule. Reactive astrocytes proliferated in the external capsule 17 days following inoculation. To avoid this irreversible brain atrophy, the inoculated adenovirus should be reduced to less than 1 x 10(7) particles (2.6 x 10(5) pfu) in mice. DISCUSSION: Our results indicate the presence of a unique and diffuse immune response of the brain; therefore, the clinical use of recombinant virus for intraventricular gene transfer must be carefully evaluated.

A head holder for magnetic resonance imaging that allows the stereotaxic alignment of spontaneously occurring intracranial mouse tumors.

The use of stereotaxic neurosurgery in rodent models of human disease requires the alignment of central nervous system (CNS) structures that can be identified and surgically approached with great accuracy. Current technologies make possible development of mouse lines with enhanced predispositions for the development of various diseases including tumors. When such tumors arise in the brain their location is unpredictable. Obtaining a biopsy or stereotaxically delivering local therapy requires that the site of such tumors be known with great precision. We devised a method to correlate images of mouse brain tumors acquired by magnetic resonance imaging (MRI) with stereotaxic coordinates that can be used for obtaining biopsies or administering local therapy. We constructed a head holder containing a pair of tubes filled with a substance that could be imaged by MR and which were separated by varying distances. This allowed the precise localization of the tumor in all three dimensions. The strategy we employed is adaptable to other imaging modalities and to other body sites.

What is the best method for reporting tumor diameter in vestibular schwannoma?

OBJECTIVE: Various methods have been used to report the tumor diameter of vestibular schwannomas. To clarify the most appropriate method to represent the tumor volume, tumor diameters according to various measuring methods were statistically compared with the actual tumor volume. METHODS: Tumor volume was measured by three-dimensional constructive interference in steady state images in 52 unselected vestibular schwannomas. Pearson's correlation coefficient was obtained between the tumor volume and various tumor diameters, such as diameter parallel to the petrous edge (a); a pons-to-petrous diameter (b); ab, a maximum diameter of the portion in the cerebellopontine angle cistern (max CPA); a maximum diameter of the whole tumor (Max); and a diameter through an axis of the internal auditory canal (Axis). The tumors were divided into three groups on the basis of tumor volume, as follows: Group I (small, <0.5 cm(3)), Group II (medium, 0.5-2 cm(3)), and Group III (large, >2 cm(3)). RESULTS: Max and Axis correlated best with the tumor volume in Group I and correlated least with the tumor volume in Group II. Any of these measurements was acceptable in Group III tumors. The max CPA consistently revealed good correlation with the tumor volume in all three tumor groups. CONCLUSION: The max CPA measurement is the simplest and most appropriate way to represent the tumor volume in unselected tumors. Max or Axis is better only when small tumors (<0.5 cm(3) in volume) are being assessed-that is, those with a max CPA of less than 1 cm.

Internal carotid artery rotation technique to expose an aneurysm neck: technical note.

OBJECTIVE: Full exposure of a neck of an aneurysm is important to obliterate it completely. METHODS: A 51-year-old woman in whom an unruptured aneurysm projecting medially under the optic nerve was incidentally found underwent clipping surgery. The edge of the circumferentially cut distal dural ring was pulled with forceps to rotate the internal carotid artery and to expose the neck of the aneurysm. RESULTS: The neck of the aneurysm was completely obliterated under direct vision. CONCLUSION: This single, neat method exposes the neck of an unruptured paraclinoid aneurysm of the internal carotid artery.

Double-insurance bypass for internal carotid artery aneurysm surgery.

OBJECTIVE: The aim of this article is to present the usefulness of a double-bypass method in the surgical treatment of complex internal carotid artery (ICA) aneurysms. For patients with clippable but complex aneurysms of the ICA having poor collateral circulation, bypass surgery is needed before temporary occlusion of the ICA. We propose a double bypass for safety. METHODS: The superficial temporal artery was anastomosed to the distal cortical branch of the middle cerebral artery (MCA), followed by anastomosis between the radial artery and the inferior trunk of the MCA. For patients with clippable ICA aneurysms, the radial artery was temporarily anastomosed to the inferior trunk of the MCA by raising the ipsilateral forearm to the head after the radial artery was harvested. After the aneurysm had been clipped, the anastomosed radial artery was cut close to the anastomosed site and repositioned back to the original arm. RESULTS: This double-bypass procedure was performed in two patients, and no ischemic complications related to revascularization were observed. Temporary occlusion times of the MCA for superficial temporal artery-to-MCA anastomosis and radial artery-to-MCA anastomosis were 30 and 46 minutes in one patient and 28 and 55 minutes in another. CONCLUSION: This surgical procedure, which we called "double-insurance bypass," can reduce the risk of ischemic complications associated with revascularization of the ICA.

Microvascular pathological features of immediate perinidal parenchyma in cerebral arteriovenous malformations: giant bed capillaries.

OBJECT: The behavior of brain tissue in cases of arteriovenous malformations (AVMs) is a matter of debate. The authors believe that the local microvascular environment in the AVM bed shares the hemodynamic changes influencing that behavior in one way or another. The purpose of this study was to investigate the microvascular pathological features in the immediate perinidal brain tissue. METHODS: This retrospective study was conducted using excised AVM specimens obtained in 35 patients, from which the authors selected 20 specimens that fulfilled the criteria for sufficient brain tissue around the excised nidus. Specimens were stained with hematoxylin and eosin, and the immediate perinidal microvascular environment was examined using light microscopy. CONCLUSIONS: Eighty-five percent of the AVMs studied showed the presence of huge, dilated capillaries, and 65% showed severe congestion of these capillaries. The authors have named these capillaries "giant bed capillaries." In this study capillary bleeding was shown in AVMs, and a pericapillary space was seen around some vessels. The brain parenchyma containing AVMs with these findings proved to be significantly ischemic.

Clinical and neuroimaging characteristics of hydrocephalus associated with vestibular schwannoma.

OBJECT: The clinical and neuroimaging characteristics of hydrocephalus associated with vestibular schwannoma were retrospectively analyzed to improve the perioperative management of the circulation of cerebrospinal fluid. METHODS: A retrospective analysis was performed in 236 patients with unilateral vestibular schwannomas. The patients' ages ranged from 17 to 83 years (mean 53.6 +/- 13.2 years), and the diameters of the tumors the patients harbored ranged from 5 to 60 mm (mean 30.5 +/- 12.7 mm). Hydrocephalus was present before tumor resection in 33 patients (14%) and in six of these patients focal dilation of the sylvian fissures was noted. There was a significant correlation between the incidence of hydrocephalus and tumor size. The incidence of preoperative hydrocephalus among elderly patients (> or = 65 years of age) was 28.6% and that among younger patients (< 65 years of age) was 10.8%. Tumors in elderly patients with hydrocephalus (mean tumor diameter 32.8 +/- 11.7 mm; 12 patients) were significantly smaller than those in younger patients (mean tumor diameter 41.7 +/- 10.9 mm; 21 patients). Among patients with tumors smaller than 30 mm (114 patients), the incidence of hydrocephalus in elderly patients (25%) was 12-fold higher than that in younger patients (2.1%). Six patients with hydrocephalus who had focal dilation of the sylvian fissures were significantly older than 27 patients with hydrocephalus in whom there was no focal dilation. The dilated sylvian fissures collapsed in two patients spontaneously after tumor resection and in the other four patients after shunt placement. CONCLUSIONS: The incidence of associated hydrocephalus is higher in older patients. Communicating hydrocephalus tends to occur in elderly patients. Enlargement of the ventricles with focal dilation of the sylvian fissures should not be misinterpreted as physiological brain atrophy.

Growth pattern and rate in residual nonfunctioning pituitary adenomas: correlations among tumor volume doubling time, patient age, and MIB-1 index.

OBJECT: Surgical cure can be achieved in pituitary adenomas when they are completely removed. It is controversial whether postoperative radiation therapy should be given to prevent recurrence, and whether an early reoperation should be performed for residual adenomas, because we have little information about the natural history of postoperative residual adenomas. METHODS: The residual tumor volume was serially measured in 40 nonfunctioning pituitary adenomas (NFPAs) and the tumor volume doubling time (TVDT) was calculated. Correlations between the patients' age, tumor volume, log TVDT, and MIB-1 index were examined. Other factors including the patient's sex, cavernous sinus (CS) invasion by the tumor, or presence of an intratumoral cyst were analyzed to assess their influence on the TVDT. Values are expressed as the means +/- standard deviations. Thirty-eight adenomas increased in volume and two decreased during a follow-up period ranging from 4 to 141 months (mean 52.5 months). Exponentially linear tumor growth was observed in the 38 growing adenomas regardless of the residual tumor volume, with the TVDT ranging from 506 to 5378 days (mean 1836 days). The patients' age was 57.1 +/- 15.7 years (range 15-79 years), the tumor volume at the beginning of the magnetic resonance imaging observation period was 2.5 +/- 2.2 cm3 (range 0.07-14.5 cm3), and the MIB-1 index was 0.73 +/- 0.68% (range 0.1-2.9%). There was a correlation between the log TVDT and patient age (R = 0.73), an inverse correlation between the log TVDT and MIB-1 index (r = -0.49), and an inverse correlation between the MIB-1 index and patient age (r = -0.61). A significant difference (p = 0.0001) was noted between the TVDT (1,106 days) in the 19 patients younger than 61 years of age and the TVDT (2566 days) in the 19 patients who were 61 years of age or older. There was also a significant difference (p = 0.0002) between the age (50.8 +/- 15.3 years) of the patients with rapidly growing tumors (TVDT < 1,836 days, 24 patients) and the age (69.1 +/- 7.6 years) of the patients with slowly growing tumors (TVDT> 1836 days, 14 patients). Other factors including the patients' sex, CS invasion, and intratumoral cyst formation did not affect the TVDT of residual NFPAs. CONCLUSIONS: The tumor growth rate of residual NFPAs is strongly influenced by the patient's age. The TVDT in elderly patients is much longer than that previously reported. Treatment strategies that take into consideration the natural history of residual adenomas should be established especially in the elderly population.

Radiometric analysis of paraclinoid carotid artery aneurysms.

OBJECT: Classification of paraclinoid carotid artery (CA) aneurysms based on their associated branching arteries has been confusing because superior hypophyseal arteries (SHAs) are too fine to appear opacified on cerebral angiograms. The authors performed a retrospective radiometric analysis of surgically treated paraclinoid aneurysms to elucidate their angiographic and anatomical characteristics. METHODS: A retrospective analysis was made of 85 intradural paraclinoid aneurysms in which the presence or absence of branching arteries had been determined at the time of surgical clipping. The lesions were classified as supraclinoid, clinoid, and infraclinoid aneurysms based on their relation to the anterior clinoid process on lateral angiograms of the CA. The direction of the aneurysms were measured according to angles formed between the medial portion of the horizontal line crossing the aneurysm sac and the center of the aneurysm neck on anteroposterior angiograms. Branching arteries were associated with 68 aneurysms, of which 28 were ophthalmic artery (OphA) lesions (32.9%) and 40 were SHA ones (47.1%); associated branching arteries were absent in 17 aneurysms (20%). Twenty-five aneurysms (29.4%) were located at the supraclinoidal level, 46 (54.1%) at the clinoidal, and 14 (16.5%) at the infraclinoidal. The majority of aneurysms identified at the supraclinoidal level were OphA lesions (44%) or those unassociated with branching arteries (48%), with mean directions of 57 degrees or 67 degrees, respectively. At the clinoidal level, the mean directions of aneurysms were 76 degrees in six lesions unassociated with branching arteries (13%), 43 degrees in 16 OphA lesions (35%), and -11 degrees in 24 SHA ones (52%). All aneurysms at the infraclinoidal level arose at the origin of the SHAs, with a mean direction of -29 degrees, and most of these were embedded in the carotid cave. CONCLUSIONS: Aneurysms arising from the SHA can be distinguished from those not located at an arterial division by cerebral angiography, because SHA lesions are usually located at the medial or inferomedial wall of the internal carotid artery at the clinoidal or infraclinoidal level. Their distribution correlates well with the reported distribution of SHA origins. The carotid cave aneurysm is a kind of SHA lesion that originates at the most proximal intradural CA.

Spatial learning transiently disturbed by intraventricular administration of ouabain.

The presence of sodium-potassium-adenosine triphosphatase (Na+,K+-ATPase) on the surface of arachnoid cells indicates that active transport of electrolytes and water occurs there. Previously, we accidentally found that intraventricular administration of TGF-beta1 impaired rat spatial learning. Levels of Na+,K+ -ATPase were decreased in arachnoid cells with fibrosis. To characterize the role of the Na+,K+ -ATPase, Wistar rats were intraventricularly administered a total of 200 microl of ouabain, at concentrations of 10(-5), 10(-4) and 10(-3) M, for one week with an osmotic pump, and were examined with a Morris water maze. Latency for reaching the platform did not significantly differ between ouabain-administered rats and controls. Spatial learning was impaired in a dose-dependent manner. Na+,K+ -ATPase activity of arachnoid cells ceased during ouabain administration, and recovered completely three weeks after the end of ouabain administration. The present results suggest that the Na+,K+ -ATPase on the surface of arachnoid cells contributes to maintenance of rat spatial learning.

Nephrotic syndrome due to primary AL amyloidosis, successfully treated with VAD and subsequent high-dose melphalan followed by autologous peripheral blood stem cell transplantation.

Primary AL amyloidosis involves vital organs from the early phase of illness, resulting in a poor prognosis. We report a patient with nephrotic syndrome due to this type of amyloidosis, who was successfully treated with two courses of VAD (vincristine, doxorubicin and dexamethasone) and subsequent high-dose melphalan (140 mg/m2) with autologous stem cell support. Following the serial chemotherapy his proteinuria improved, and M protein became undetectable in both serum and urine. To avoid the progression of primary AL amyloidosis, intensive chemotherapy should be actively used when the general status and vital organ functions are well preserved.

Chronic subdural hematoma after transsphenoidal surgery.

Chronic subdural haematoma has not been reported as a complication of transsphenoidal surgery. We present a case of pituitary adenoma which was gross-totally removed by transsphenoidal surgery with the enlarged sellar opening. Postoperative serial imaging showed massive air accumulation in both frontal subdural spaces followed by subdural fluid collection and subsequent chronic subdural haematomas 2 months later. We conclude that close follow up imaging study is required to avoid overlooking chronic subdural haematoma when massive air is introduced into the subdural space by the transsphenoidal surgery.

Protective dural flap for bone drilling at the paraclinoid region and porus acusticus--technical note.

A new method was developed to avoid the risk of injury to the cranial nerves and vessels during intradural bone resection at the paraclinoid region and porus acusticus. The semicircular dural flap is pulled out with a thread over the anterior clinoid process or the porus acusticus. The flap is extended over the underlying structures with a tapered spatula to create adequate space for drilling the bone. The site for drilling was adequately exposed and bone was drilled away smoothly without damaging the underlying vessels and nerves in 10 patients with paraclinoid aneurysms and in seven patients with vestibular schwannomas. This "protective dural flap" method provides wide exposure for drilling, protects the underlying structures, and allows quick inspection during bone resection.

Disturbed spatial learning of rats after intraventricular administration of transforming growth factor-beta 1.

Patients with subarachnoid hemorrhage (SAH) who later suffer hydrocephalus show persistently high levels of transforming growth factor-beta 1 (TGF-beta 1) in the cerebrospinal fluid after the onset of SAH. Recombinant TGF-beta 1 induces hydrocephalus in mice. This study examined the spatial learning ability of rats after intraventricular administration of TGF-beta 1. Thirteen-week-old Wistar rats were treated with 0.8 or 8.0 micrograms of human recombinant TGF-beta 1 by direct injection or via osmotic pump. Three months later, their spatial learning ability was evaluated with a Morris water maze. Ventricular size, ultrastructural features, and sodium-potassium-adenosine triphosphatase (Na+, K(+)-ATPase) activity of the subarachnoid space were examined. All three TGF-beta 1-treated groups clearly exhibited impaired spatial learning ability, but they did not exhibit ventricular dilation. Histological examination revealed subarachnoid fibrosis and deactivation of Na+, K(+)-ATPase in the arachnoid cells. These findings are similar to those of our previous experiments involving injection of TGF-beta 1 in mice. The present and previous studies suggest that subarachnoid fibrosis is an important factor in the disturbance of the spatial learning ability of rats, whereas ventricular size is less important.

[Treatment of craniopharyngiomas in children].

PURPOSE: The purpose of this article is to assess, in a 25-year retrospective study, the clinical outcome in children with craniopharyngioma. PATIENT AND METHODS: From 1978 to 2002, 12 children younger than 15-year-old underwent treatment with surgery and/or radiotherapy for craniopharyngioma. The clinical course and outcome were reviewed. RESULTS: The median age was 7.3 years (range, 3 to 12 years) at the time of initial surgical resection. With a mean follow-up period of 132 months (range, 29 to 255 months), 1 patient died of tumor progression due to malignant transformation at 205 months after the initial surgery and the overall outcome was good in 11 patients. Out of 12 patients 4 presented a recurrence of their tumor, 2 after an apparently gross total removal. Because of tumor recurrence, 2 received conventional radiation therapy and 3 received gamma knife radiosurgery. There was neither operative mortality nor major complication. All patients required hormonal replacement postoperatively. CONCLUSIONS: The goal in the treatment of craniopharyngiomas is to achieve total removal without morbidity. Our results compared favorably with the previous reports in the literature. MRI follow-up should be performed even in patients whose primary tumor is resected "completely". Suitable combination of open surgery, conventional radiotherapy and gamma knife radiosurgery may result in optimal functional outcome. Recovery from postoperative pituitary dysfunction can be occasionally expected.

Role of GalNAc4S-6ST in astrocytic tumor progression.

N-Acetylgalactosamine 4-sulfate 6-O-sulfotransferase (GalNAc4S-6ST) is the sulfotransferase responsible for biosynthesis of highly sulfated chondroitin sulfate CS-E. Although involvements of CS-E in neuronal cell functions have been extensively analyzed, the role of GalNAc4S-6ST in astrocytic tumor progression remains unknown. Here, we reveal that GalNAc4S-6ST transcripts were detected in astrocytic tumors derived from all 30 patients examined using quantitative reverse transcription-PCR analysis. Patients with high GalNAc4S-6ST mRNA expression had significantly worse outcome compared with patients with low expression, and multivariate survival analysis disclosed that GalNAc4S-6ST is an independent poor prognostic factor for astrocytic tumors. We then tested whether CS-E enhanced haptotaxic migration of glioblastoma U251-MG cells that endogenously express both the CS-E's scaffold tyrosine phosphatase ζ (PTPζ) and GalNAc4S-6ST, in the presence of CS-E's preferred ligands, pleiotrophin (PTN) or midkine (MK), using a modified Boyden chamber method. Haptotaxic stimulation of cell migration by PTN was most robust on control siRNA-transfected U251-MG cells, while that enhancing effect was cancelled following transduction of GalNAc4S-6ST siRNA. Similar results were obtained using MK, suggesting that both PTN and MK enhance migration of U251-MG cells by binding to CS-E. We also found that PTPζ as well as PTN and MK were frequently expressed in astrocytic tumor cells. Thus, our findings indicate that GalNAc4S-6ST mRNA expressed by astrocytic tumor cells is associated with poor patient prognosis likely by enhancing CS-E-mediated tumor cell motility in the presence of PTN and/or MK.