Efficient production of JC virus in SVG cells and the use of purified viral antigens for analysis of specific humoral and cellular immune response

A new in vitro system for the production of the human polyomavirus JC virus (JCV) was established to circumvent the need for virus growth in primary human fetal glial cells (PHFG). The permanent cell line SVG, transformed by an origin-defective mutant of Simian Virus 40 (SV40) was used to grow JCV. JCV-specific RNA could be detected at day 5 and viral antigen at day 6 post infection (p.i.). Virus production peaked at day 16. Virus could be purified by differential centrifugation. The purified fraction consisted mainly of mature particles but contained also pentamers of the major structural virus protein 1 (VP1). The VP1-pentamers could be purified to near homogeneity. The purified virus particles stimulated a specific T-cell proliferation of peripheral blood monocytes (PBMCs) of a patient with progressive multifocal leukoencephalopathy (PML) and of two healthy individuals. In addition, JCV-particles and VP1-pentamers reacted specifically in an ELISA with a series of five PML-patient sera and four sera of individuals not affected by PML. These results demonstrate that purified whole virus particles are suitable for the analysis of specific cellular and humoral immune responses to JCV.     

Improving collaborative learning in the classroom: Text mining based grouping and representing

Orchestrating collaborative learning in the classroom involves tasks such as forming learning groups with heterogeneous knowledge and making learners aware of the knowledge differences. However, gathering information on which the formation of appropriate groups and the creation of graphical knowledge representations can be based is very effortful for teachers. Tools supporting cognitive group awareness provide such representations to guide students during their collaboration, but mainly rely on specifically created input. Our work is guided by the questions of how the analysis and visualization of cognitive information can be supported by automatic mechanisms (especially using text mining), and what effects a corresponding tool can achieve in the classroom. We systematically compared different methods to be used in a Grouping and Representing Tool (GRT), and evaluated the tool in an experimental field study. Latent Dirichlet Allocation proved successful in transforming the topics of texts into values as a basis for representing cognitive information graphically. The Vector Space Model with Euclidian distance based clustering proved to be particularly well suited for detecting text differences as a basis for group formation. The subsequent evaluation of the GRT with 54 high school students further confirmed the GRT’s impact on learning support: students who used the tool added twice as many concepts in an essay after discussing as those in the unsupported group. These results show the potential of the GRT to support both teachers and students.     

Supporting controversial CSCL discussions with augmented group awareness tools

This paper describes the development of augmented group awareness tools that take mutual user ratings of their online discussion contributions as input, aggregate these data, and visually feed these data back to the members in real time, thereby informing participants about how the group as a whole perceives their contributions. A specific group awareness tool was experimentally tested in a CSCL scenario using online controversies about a physics domain. The learning material was distributed across group members to create a situation where an individual minority member with a scientifically correct viewpoint faces a majority favoring a plausible, but incorrect viewpoint. It was hypothesized that in unsupported CSCL groups an incorrect majority would dominate a correct minority, whereas in groups that were supported by an augmented group awareness tool minority influence could be strengthened by making minority contributions salient. The paper reports results in support of this hypothesis, and discusses the mechanisms leading to the benefits of group awareness tools for collaborative learning.     

Diagnosis of Creutzfeldt-Jakob disease by two-dimensional gel electrophoresis of cerebrospinal fluid

BACKGROUND: The diagnosis of Creutzfeldt-Jakob disease (CJD) is based on clinical and electroencephalographic criteria which do not allow a reliable diagnosis to be made during life. METHODS: Serum and cerebrospinal fluid (CSF) samples were obtained after informed consent from relatives of suspected cases of CJD referred to the German CJD surveillance unit. CSF samples from 58 definite (neuropathologically verified), 46 probable, and 34 possible CJD cases, and from 44 patients without CJD were analysed by two-dimensional gel electrophoresis (2-DE). Two investigators blinded to clinical findings recorded the presence of two proteins, p130/131. The kappa value for the level of agreement between these investigators was calculated. Results obtained were compared with the determination of neuron-specific enolase (NSE) in CSF. NSE concentrations of more than 35 ng/mL were considered indicative of CJD. FINDINGS: p130/131 was detected in 81% of definite (47/58), 80% of probable (37/46), 68% of possible (23/34) CJD cases, and in none of the other 44 cases. NSE concentrations of more than 35 ng/mL were seen in 79% of definite (46/58), 80% of probable (37/46), 59% of possible (20/34) CJD cases, and 9% of other cases (4/43). The positive predictive value for 2-DE of CSF is 100% and the negative predictive value is 69%. The level of agreement for the detection of p130/131 by two evaluators in a subset of 141 2-DE gels was a kappa of 0.93 (95% CI 0.86-0.99). Of 13 cases initially classified as possible and later reclassified as definite, ten cases were identified correctly by the 2-DE analysis, indicating a better diagnostic accuracy of this test compared with the current clinical classification. None of nine cases classified as other by neuropathology had p130/131 in 2-DE. INTERPRETATION: 2-DE for p130/131 is a specific test for the diagnosis of CJD. These data suggest including detection of p130/131 as a criterion for the diagnosis of probable CJD in addition to the currently accepted criteria of a rapidly progressive dementia of less than 2 years duration, typical neurological signs, and periodic sharp-wave complexes in the EEG.     

A Case Study for End of Life Reuse and Recycling Survey Methodologies： The Hollentalanger Cottage

Up to now, reuse and recycling of existing buildings have not been examined widely. This paper discusses the theories, methods and practicalities of buildings＇ end of life with a main focus on planning and managing reuse and recycling of existing buildings. Our aim is the realistic modelling of theoretical scenarios for end of life based on a case study. The methods of building survey, material classification and documentation for reuse, recycling and disposal of existing constructions are presented. Investigations and calculations were done on an existing cottage in the Alps. The ecologically most beneficial disposal phase of the old wooden hut is our main objective. Critical questions arise from the quality of the material and how it can be extracted, separated and balanced in an appropriate way. A systematic survey of the building by inspection of constructions and materials in iterative steps allows a detailed material balance with condition and property information. This information is crucial for scenarios and material flow analysis of demolished and rebuilt building in environmental system analysis. For future planning, the reuse and recycling of existing buildings should be integrated quite early in the planning process so that we can use the materials in the best way.