Back to Search | Help | Tutorial Search Within Results | New Search | Save This Search | RSS Feed
Sort By: RelevancePublication Date (newest to oldest)Publication Date (oldest to newest)Title (A to Z)Title (Z to A)Author (A to Z)Author (Z to A)Source (A to Z)Source (Z to A)
Use My Clipboard to print, email, export, and save records. More Info: Help 0 items in My Clipboard
Now showing results 1-10 of 910. Next 10 >>
1. Naive CD8 T-Cells Initiate Spontaneous Autoimmunity to a Sequestered Model Antigen of the Central Nervous System (EJ810617)
Author(s):
Na, Shin-Young; Cao, Yi; Toben, Catherine; Nitschke, Lars; Stadelmann, Christine; Gold, Ralf; Schimpl, Anneliese; Hunig, Thomas
Source:
Brain, v131 n9 p2353-2365 Sep 2008
Pub Date:
2008-09-00
Pub Type(s):
Journal Articles; Reports - Research
Peer-Reviewed:
Yes
Descriptors: Animals; Disabilities; Anatomy; Diseases; Cytology; Role; Brain; Molecular Structure; Diagnostic Tests; Models; Neurology
Abstract: In multiple sclerosis, CD8 T-cells are thought play a key pathogenetic role, but mechanistic evidence from rodent models is limited. Here, we have tested the encephalitogenic potential of CD8 T-cells specific for the model antigen ovalbumin (OVA) sequestered in oligodendrocytes as a cytosolic molecule. We show that in these "ODC-OVA" mice, the neo-self antigen remains invisible to CD4 cells expressing the OVA-specific OT-II receptor. In contrast, OVA is accessible to naive CD8 T-cells expressing the OT-I T-cell receptor, during the first 10 days of life, resulting in antigen release into the periphery. Introduction of OT-I as a second transgene leads to fulminant demyelinating experimental autoimmune encephalomyelitis with multiple sclerosis-like lesions, affecting cerebellum, brainstem, optic nerve and spinal cord. OVA-transgenic oligodendrocytes activate naive OT-I cells "in vitro", and both major histocompatibility complex class I expression and the OT-I response are further up-regulated by interferon-[gamma] (IFN-[gamma]). Release of IFN-[gamma] into the circulation of ODC-OVA/OT-I double transgenic mice precedes disease manifestation, and pathogenicity of OT-I cells transferred into ODC-OVA mice is largely IFN-[gamma] dependent. In conclusion, naive CD8 T-cells gaining access to an "immune-privileged" organ can initiate autoimmunity via an IFN-[gamma]-assisted amplification loop even if the self-antigen in question is not spontaneously released for presentation by professional antigen presenting cells. Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
Related Items: Show Related Items
Full-Text Availability Options:
More Info: Help | Tutorial Help Finding Full Text | More Info: Help Find in a Library | Publisher's Web Site
2. Genetic and Pharmacological Intervention for Treatment/Prevention of Hearing Loss (EJ799984)
Cotanche, Douglas A.
Journal of Communication Disorders, v41 n5 p421-443 Sep-Oct 2008
2008-00-00
Journal Articles; Reports - Descriptive
Descriptors: Hearing Impairments; Genetics; Anatomy; Intervention; Prevention; Animals; Molecular Structure; Sensory Experience
Abstract: Twenty years ago it was first demonstrated that birds could regenerate their cochlear hair cells following noise damage or aminoglycoside treatment. An understanding of how this structural and functional regeneration occurred might lead to the development of therapies for treatment of sensorineural hearing loss in humans. Recent experiments have demonstrated that noise exposure and aminoglycoside treatment lead to apoptosis of the hair cells. In birds, this programmed cell death induces the adjacent supporting cells to undergo regeneration to replace the lost hair cells. Although hair cells in the mammalian cochlea undergo apoptosis in response to noise damage and ototoxic drug treatment, the supporting cells do not possess the ability to undergo regeneration. However, current experiments on genetic manipulation, gene therapy, and stem cell transplantation suggest that regeneration in the mammalian cochlea may eventually be possible and may 1 day provide a therapeutic tool for hearing loss in humans. Learning outcomes: The reader should be able to: (1) Describe the anatomy of the avian and mammalian cochlea, identify the individual cell types in the organ of Corti, and distinguish major features that participate in hearing function, (2) Demonstrate a knowledge of how sound damage and aminoglycoside poisoning induce apoptosis of hair cells in the cochlea, (3) Define how hair cell loss in the avian cochlea leads to regeneration of new hair cells and distinguish this from the mammalian cochlea where there is no regeneration following damage, and (4) Interpret the potential for new approaches, such as genetic manipulation, gene therapy and stem cell transplantation, could provide a therapeutic approach to hair cell loss in the mammalian cochlea. (Contains 9 figures.) Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
3. Cardiac Cells Beating in Culture: A Laboratory Exercise (EJ775473)
Weaver, Debora
American Biology Teacher, v69 n7 p407-410 Sep 2007
2007-09-00
Guides - Classroom - Teacher; Journal Articles
Descriptors: Science Laboratories; Anatomy; Biology; Laboratory Experiments; Science Instruction; Molecular Biology; Molecular Structure
Abstract: This article describes how to establish a primary tissue culture, where cells are taken directly from an organ of a living animal. Cardiac cells are taken from chick embryos and transferred to culture dishes. These cells are not transformed and therefore have a limited life span. However, the unique characteristics of cardiac cells are maintained and students are able to see that living tissue can continue to survive in a differentiated state, even outside of the whole organism. Cardiac cells have a unique feature--they are able to contract without input from the nervous system. Each cell contracts (or beats) at its own inherent pace (Johnson, 2003). In vivo, when the cells become attached to one another, they will communicate and will synchronize their beating (Johnson, 2003; Jongsma et al., 1987). In this laboratory exercise, the student can observe the beating of cardiac cells--individually and in unison. (Contains 3 figures.) Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
4. Experimenting with Photoelectrochemical Cells in Drinking Straws: Practical Aids for Learning about Solar Energy in School or at Home (EJ791520)
Appleyard, S. J.
Physics Education, v43 n3 p270-279 May 2008
2008-05-00
Guides - Classroom - Teacher; Journal Articles; Reports - Descriptive
Descriptors: Energy; Science Instruction; Science Experiments; Light; Chemistry; Hands on Science; Scientific Concepts
Abstract: Photoelectrochemical cells using dye-sensitized ZnO with a Cu[superscript 2+]/Fe[superscript 2+]/Fe[superscript 3+] electrolyte can be easily made at home or in a school classroom with household chemicals and other readily available materials. The cells, which are made with wire housed within plastic drinking straws, have open-circuit voltages of 0.5-0.7 V and short-circuit currents of about 0.5-2.5 mA cm[superscript -2]. Step-by-step instructions are provided on how to construct the photoelectrochemical cells, as are suggestions about how to use the cells to explore some concepts associated with utilizing solar energy. (Contains 5 figures and 1 table.) Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
5. The Relationship between the Field-Shifting Phenomenon and Representational Coherence of Place Cells in CA1 and CA3 in a Cue-Altered Environment (EJ779769)
Lee, Inah; Knierim, James J.
Learning & Memory, v14 n11 p807-815 Nov 2007
2007-11-00
Descriptors: Cues; Cognitive Processes; Environmental Influences; Animals; Brain Hemisphere Functions; Spatial Ability
Abstract: Subfields of the hippocampus display differential dynamics in processing a spatial environment, especially when changes are introduced to the environment. Specifically, when familiar cues in the environment are spatially rearranged, place cells in the CA3 subfield tend to rotate with a particular set of cues (e.g., proximal cues), maintaining a coherent spatial representation. Place cells in CA1, in contrast, display discordant behaviors (e.g., rotating with different sets of cues or remapping) in the same condition. In addition, on average, CA3 place cells shift their firing locations (measured by the center of mass, or COM) backward over time when the animal encounters the changed environment for the first time, but not after that first experience. However, CA1 displays an opposite pattern, in which place cells exhibit the backward COM-shift only from the second day of experience, but not on the first day. Here, we examined the relationship between the environment-representing behavior (i.e., rotation vs. remapping) and the COM-shift of place fields in CA1 and CA3. Both in CA1 and CA3, the backward (as well as forward) COM-shift phenomena occurred regardless of the rotating versus remapping of the place cell. The differential, daily time course of the onset/offset of backward COM-shift in the cue-altered environment in CA1 and CA3 (on day 1 in CA1 and from day 2 onward in CA3) stems from different population dynamics between the subfields. The results suggest that heterogeneous, complex plasticity mechanisms underlie the environment-representating behavior (i.e., rotate/remap) and the COM-shifting behavior of the place cell. Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
6. Neurogenesis and the Spacing Effect: Learning over Time Enhances Memory and the Survival of New Neurons (EJ768155)
Sisti, Helene M.; Glass, Arnold L.; Shors, Tracey J.
Learning & Memory, v14 n5 p368-375 May 2007
2007-05-00
Descriptors: Time Factors (Learning); Animals; Retention (Psychology); Brain; Intervals; Learning Processes; Neurological Organization; Adults; Physiology; Training; Experiments; Behavioral Science Research; Animal Behavior
Abstract: Information that is spaced over time is better remembered than the same amount of information massed together. This phenomenon, known as the spacing effect, was explored with respect to its effect on learning and neurogenesis in the adult dentate gyrus of the hippocampal formation. Because the cells are generated over time and because learning enhances their survival, we hypothesized that training with spaced trials would rescue more new neurons from death than the same number of massed trials. In the first experiment, animals trained with spaced trials in the Morris water maze outperformed animals trained with massed trials, but there was not a direct effect of trial spacing on cell survival. Rather, animals that learned well retained more cells than animals that did not learn or learned poorly. Moreover, performance during acquisition correlated with the number of cells remaining in the dentate gyrus after training. In the second experiment, the time between blocks of trials was increased. Consequently, animals trained with spaced trials performed as well as those trained with massed, but remembered the location better two weeks later. The strength of that memory correlated with the number of new cells remaining in the hippocampus. Together, these data indicate that learning, and not mere exposure to training, enhances the survival of cells that are generated 1 wk before training. They also indicate that learning over an extended period of time induces a more persistent memory, which then relates to the number of cells that reside in the hippocampus. Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
7. A Constructivist Approach to Inquiry-Based Learning: A TUNEL Assay for the Detection of Apoptosis in Cheek Cells (EJ813860)
Correiro, Elizabeth E.; Griffin, Leanne R.; Hart, Peter E.
American Biology Teacher, v70 n9 p457-460 Oct 2008
2008-10-00
Descriptors: Constructivism (Learning); Research Design; Inquiry; Cooperative Learning; Active Learning; Laboratories; Biology; Learning Experience; Science Instruction; Teaching Methods; Group Discussion; Prior Learning
Abstract: A laboratory exercise is presented that incorporates constructivist principles into a learning experience designed for upper-level university biology courses. The specific objectives for this exercise are as follows: (1) To introduce students to cancer biology and to the regulation of programmed cell death as part of the cell cycle; (2) To engage students in scientific inquiry through experimental design and testing, using a constructivist approach; and (3) To encourage cooperative learning in a scientific laboratory setting. This exercise uses a modified Terminal deoxynucleotidyl Transferase Biotin-dUTP Nick End Labeling (TUNEL) assay to investigate apoptosis in human cheek cells. (Contains 3 figures and 2 tables.) Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
8. Channels Active in the Excitability of Nerves and Skeletal Muscles across the Neuromuscular Junction: Basic Function and Pathophysiology (EJ799493)
Goodman, Barbara E.
Advances in Physiology Education, v32 n2 p127-135 Jun 2008
2008-06-00
Descriptors: Human Body; Physiology; Diseases
Abstract: Ion channels are essential for the basic physiological function of excitable cells such as nerve, skeletal, cardiac, and smooth muscle cells. Mutations in genes that encode ion channels have been identified to cause various diseases and disorders known as channelopathies. An understanding of how individual ion channels are involved in the activation of motoneurons and their corresponding muscle cells is essential for interpreting basic neurophysiology in nerves, the heart, and skeletal and smooth muscle. This review article is intended to clarify how channels work in nerves, neuromuscular junctions, and muscle function and what happens when these channels are defective. Highlighting the human diseases that result from defective ion channels is likely to be interesting to students in helping them choose to learn about channel physiology. Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
9. Stem Cell Research and Health Education (EJ795559)
Eve, David J.; Marty, Phillip J.; McDermott, Robert J.; Klasko, Stephen K.; Sanberg, Paul R.
American Journal of Health Education, v39 n3 p167-179 May-Jun 2008
Descriptors: Health Education; Ethics; Diseases; Medical Research; Scientific Research; Cytology; Federal Legislation
Abstract: Stem cells are being touted as the greatest discovery for the potential treatment of a myriad of diseases in the new millennium, but there is still much research to be done before it will be known whether they can live up to this description. There is also an ethical debate over the production of one of the most valuable types of stem cell: the embryonic form. Consequently, there is public confusion over the benefits currently being derived from the use of stem cells and what can potentially be expected from their use in the future. The health educator's role is to give an unbiased account of the current state of stem cell research. This paper provides the groundwork by discussing the types of cells currently identified, their potential use, and some of the political and ethical pitfalls resulting from such use. (Contains 2 tables.) Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
10. Systems Modelling and the Development of Coherent Understanding of Cell Biology (EJ785998)
Verhoeff, Roald P.; Waarlo, Arend Jan; Boersma, Kerst Th.
International Journal of Science Education, v30 n4 p543-568 Mar 2008
2008-03-00
Descriptors: Cytology; Biology; Teaching Methods; Educational Research; Secondary Education; Plants (Botany); Metacognition; Case Studies; Models; Instructional Effectiveness
Abstract: This article reports on educational design research concerning a learning and teaching strategy for cell biology in upper-secondary education introducing "systems modelling" as a key competence. The strategy consists of four modelling phases in which students subsequently develop models of free-living cells, a general two-dimensional model of cells, a three-dimensional model of plant cells, and finally they are engaged in formal thinking by modelling life phenomena to a hierarchical systems model. The strategy was thought out, elaborated, and tested in classrooms in several research cycles. Throughout the field-tests, research data were collected by means of classroom observations, interviews, audio-taped discussions, completed worksheets, written tests, and questionnaires. Reflection on the research findings eventuated in reshaping and formalizing the learning and teaching strategy, which is presented here. The results show that although acquiring systems thinking competence at the metacognitive level needs more effort, our strategy contributed to improving learning outcomes; that is, acquisition of a coherent conceptual understanding of cell biology and acquisition of initial systems thinking competence, with modelling being the key activity. (Contains 1 table, 4 figures, and 2 notes.) Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
Help
Help