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.

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.

Gliosarcoma arising from a fibrillary astrocytoma.

We report a 67-year-old woman who was diagnosed with a gliosarcoma at a second operation after diagnosis of a fibrillary astrocytoma 5 months previously. Initially, she underwent a CT-guided stereotactic biopsy. Histological examination showed fibrillary astrocytoma (World Health Organization [WHO] grade II). Loss of heterozygosity (LOH) on 1p, 10q, and 19q was not detected. She received chemotherapy, but no radiotherapy. Five months after the biopsy, MRI revealed rapid tumor growth. Tissue obtained from partial removal of the tumor revealed gliosarcoma (WHO grade IV), and LOH on 10q and 19q was detected. The history, histopathology, and genetic alterations of this patient are discussed.

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.

A case report and review of the literature.

Primary diffuse leptomeningeal gliomatosis (PDLG) is a rare central nervous system neoplasm in which gliomatous tissue is diffusely identified in the subarachnoid space with no evidence of a primary intraparenchymal tumor. A 52-year-old man presented low back pain followed by sudden unconsciousness and had also cognitive dysfunction and meningeal sign. Examinations of cerebrospinal fluid (CSF) did not show malignant cells but increased protein and pleocytosis. Magnetic resonance (MR) imaging demonstrated diffuse leptomeningeal enhancement without any source of intraparenchymal lesion. Fluid-attenuated inversion recovery (FLAIR) also demonstrated individual diffuse high intensity area in the subarachnoid space. A biopsy disclosed wide spreading of anaplastic glial cells within the leptomeninges. He died 3 months later because of disease progression despite both radiotherapy and chemotherapy. Post-mortem examination identified PDLG and several neuropathological features of glioblastoma as well. Reviewing previous cases of PDLG instructs that this entity is rare, resembles meningitis in clinical pictures, usually occurs in a relatively younger population and has more progressive clinical course than the ordinary form of malignant gliomas.

Presurgical factors affecting patient satisfaction with pallidal surgery in Parkinson's disease.

OBJECTIVE: To evaluate presurgical factors affecting patient satisfaction with pallidal surgery. METHODS: Forty-one parkinsonian patients who underwent unilateral pallidal surgery replied to a questionnaire on general satisfaction with the outcome of surgery graded on a five-point scale. The contribution of age, disease duration, required activity level, Unified Parkinson's Disease Rating Scale Part II activity of daily living (ADL) score and presurgical to postsurgical ADL score change to the level of satisfaction was tested. The required activity level was defined as the physical activity level which the patients required to support their families. RESULTS: Multiple regression analysis revealed that age at surgery (p = 0.02), required activity level (p = 0.005), ADL score in the on phase at surgery (p = 0.001), and ADL score in the off phase at surgery (p = 0.0001) were significant contributors to satisfaction. CONCLUSIONS: The patients who were relatively young and required higher activity levels tended to have a higher degree of satisfaction with the outcome, while patients with advanced age tended to be less satisfied, independent of symptomatic improvement after the surgery.

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.

Intraventricular administration of hepatocyte growth factor treats mouse communicating hydrocephalus induced by transforming growth factor beta1.

Communicating hydrocephalus may occur spontaneously in elderly patients or occur as a complication of meningitis or intracranial hemorrhage, typically as a result of fibrosis along the route of cerebrospinal fluid (CSF) flow. Hepatocyte growth factor (HGF) has anti-fibrotic properties and is a promising candidate for the treatment of various fibrotic diseases. Thus, the goal of this study was to examine the effect of exogenous HGF (30 microg of human recombinant (hr) HGF intraventricularly for 7 or 14 days) in a model of hr transforming growth factor beta1-induced communicating hydrocephalus in C57BL/6 mice. HGF treatment resulted in a reduction of ventriculomegaly, as demonstrated by magnetic resonance imaging, and improved spatial memory. Further, ink passage test demonstrated improvement of normalized CSF in flow in mice receiving HGF treatment as opposed to delayed CSF flow in the hydrocephalic mice at baseline. Finally, histological examination in hydrocephalic mice undergoing HGF treatment revealed reduction of collagen fibers in the meninges and normalization of their structures. These results indicate that exogenous HGF may be of utility in the treatment of hydrocephalus in humans.

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.

Lack of benefit of spinal irradiation in the primary treatment of intracranial germinoma: a multiinstitutional, retrospective review of 180 patients.

BACKGROUND: The current study assessed the contribution of spinal irradiation to the treatment outcome of patients with intracranial germinoma. METHODS: Clinical data from 180 patients with intracranial germinoma, who were treated with radiotherapy and/or chemotherapy from 1980 to 2001, were collected from 6 institutions. The patients' median age was 16 years (range, 1-47 yrs), and the male-to-female ratio was 133:47. Pathologic verification was obtained in 88 patients. A solitary tumor was seen in 129 patients, and multifocal or disseminated tumors were detected in 51 patients. The median tumor size was 2.5 cm (range, 0.6-7.0 cm). Local field and/or whole brain irradiation was performed in 114 patients, and craniospinal irradiation was performed in 66 patients. Fifty-five patients were treated with chemotherapy. The median follow-up time was 89 months (range, 3-297 mos). RESULTS: Eight-year overall and event-free survival rates were 91% and 89%, respectively. The 8-year recurrence rates at the primary site, intracranial space, and the spinal space were 1%, 6%, and 6%, respectively. Cox regression analysis showed that spinal irradiation (hazard ratio, 1.050; 95% confidence interval [CI], 0.355-3.170) did not contribute to a favorable event-free survival. CONCLUSIONS: Spinal irradiation did not contribute to favorable event-free survival in patients with intracranial germinoma.

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.

[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.

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.

Harvesting blood stem cells from cranial bone at craniotomy--a preliminary study.

Primary brain tumors seldom infiltrate into the cranium, even if they are invasive in the central nervous system. In this study, we examined whether blood stem cells can be harvested from cranial bone at craniotomy. Bone marrow cells in cranial bone were counted in 181 craniotomy specimens after staining with hematoxylin and eosin. Marrow volume was measured in 37 specimens using three-dimensional computed tomography (CT). In 10 cases, viable cells collected from very small bone pieces at craniotomy were cultured to examine granulocyte/macrophage colony-forming units (CFU-GM). In 2 cases, bone marrow cells were practically harvested from removed bone at surgery. The weight of bone flap at craniotomy was 35.0 +/- 18.0 g. Bone flap marrow contained 1.5 x 10(9) cells/ml. CT examination showed that bone flap volume was 35.0 +/- 9.0 ml and marrow ratio was 65.1 +/- 13.5%. Thus, at craniotomy, a typical bone flap contained about 3.4 x 10(10) cells. Bone marrow cell count gradually decreased as subject age increased. The bone pieces obtained at craniotomy contained 3.1 +/- 3.4 x 10(6) cells/g, and CFU-GM count was 0.4 x 10(5) cells/g. In one case, we collected 3.4 x 10(8) cells, including 1.8 x 10(6) CFU-GM colonies. In another case, we collected 9.7 x 10(8) cells, including 4.8 x 10(6) CFU-GM colonies. These findings indicate that, at craniotomy, the number of blood stem cells in a typical bone flap is sufficient for autologous blood stem cell rescue.

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.

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.

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.

Effects of unilateral pallidotomy on voluntary movement, and simple and choice reaction times in Parkinson's disease.

We studied the effects of unilateral pallidotomy on motor execution and reaction times in patients with moderately advanced Parkinson's disease (PD). Twelve consecutive patients (7 men, 5 women; all right-handed) underwent left-side microelectrode-guided pallidotomy. In addition to clinical rating, reaction time (RT) tests and repetitive movements of the contralesional hand/arm were carried out at baseline and 2 to 3 months after surgery while patients were on optimal medical regimens (on period). The initiation time in both simple reaction time (SRT) and choice reaction time (CRT) improved significantly after pallidotomy (P < 0.05), whereas no effect was observed on the choice processing time, which was calculated by subtracting the mean value of the onset of SRT from that of CRT. Pallidotomy resulted in significant improvement of repetitive movements such as hand pronation/supination and finger-tapping (P < 0.002, P < 0.005, respectively). Improvements in RT tests and repetitive movements suggest that pallidotomy may enhance attention and motor function. These effects are probably mediated through the pallido-thalamic-cortical neural circuitry.

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.