bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiple sites in evaluation research: A survey of organizational and methodological issues
Authors: Sinacore James M. , Turpin Robin S.
Published: January 2005

The methodology of multiple sites in evaluation research requires a balance between benefits and challenges.
How state regulatory agencies address privatization: The case of wastewater treatment
Authors: Heilman John G. , Johnson Gerald W.
Published: January 2005

State regulatory agencies responsible for water quality typically have done little to develop policy or even provide information about privatization as a means for local authorities to develop wastewater treatment projects. Absent federal mandates, privatization takes place “in the shadow of positive law,” and state agencies engage in it only informally and reactively, leaving private firms and local officials to carry out the privatization option.
Conflicting expertise and uncertainty: Quality assurance in high‐level radioactive waste management
Authors: Fitzgerald Michael R. , McCabe Amy Snyder
Published: January 2005

The policy process that takes place in the siting of a high‐level nuclear waste repository is marked by political controversy, an open decision‐making process, scientific uncertainty, conflicting expert opinion, and high risk in case of system failure. Mandated quality‐assurance studies of proposed sites represent high‐stakes, high‐pressure evaluation that must take a variety of factors into account.
Challenges in evaluating a national demonstration program for homeless persons with alcohol and other drug problems
Authors: Huebner Robert B. , Crosse Scott B.
Published: January 2005

Designing an evaluation of a federally funded, multisite demonstration program for homeless persons with alcohol and other drug problems presents a number of methodological and practical challenges. Despite these challenges, a great deal can be learned about human service programs for homeless persons from multisite demonstration programs.
Voices in the design and evaluation of a multicultural education program: A developmental approach
Authors: Stockdill Stacey Hueftle , Duhon‐Sells Rose Marie , Olson Ruth Anne , Patton Michael Quinn
Published: January 2005

In this chapter, voices from one multicultural evaluation convey a sense of the struggle involved in developing an evaluation that is sensitive to and empowering of multicultural peoples and perspectives.
Standardized tests and program evaluation: Inappropriate measures in critical times
Authors: McDowell Ceasar L.
Published: January 2005

Using standardized test scores to determine program effectiveness may contribute to further inequities.
Reconsidering the use of race as an explanatory variable in program evaluation
Authors: Davis James Earl
Published: January 2005

Program evaluators often use race as an explanatory variable without clearly articulating what race means in an evaluation context.
Diagnosis and symptomatology
Authors: Hodges Kay
Published: January 2005

Numerous interview instruments are available to determine diagnosis and assess symptomatology in children and adolescents. Procedural and methodological issues that are critical to the application of these instruments in mental health evaluation studies are discussed here.
The value of evaluation
Authors: Richardson Elliott L.
Published: January 2005

Evaluation is an essential part of government administration. Scarce public resources need to be used in the most efficient and effective manner. This necessity was never more pressing than today, when the country faces a growing list of unmet social needs.
Executive branch program evaluation: An upturn soon?
Authors: Chelimsky Eleanor
Published: January 2005

General Accounting Office studies have documented a serious decline in executive branch evaluation capacity, as reflected in declining budget and staff resources and a narrowing of the methods employed and issues examined. However, increasing interest by the Office of Management and Budget and recent steps taken to encourage program evaluation should lead to its broader application and more frequent use.
Evaluation in the department of housing and urban development
Authors: Rymph David B.
Published: January 2005

In response to repeated budget and staffing reductions, the Office of Program Analysis and Evaluation developed a series of innovative approaches to lower the cost and increase the utility of its evaluation work. But, ultimately, the effort was unsuccessful, and the office was reorganized into a policy coordination office.
Expanding evaluation capabilities in the General Accounting Office
Authors: Chelimsky Eleanor
Published: January 2005

Evaluation specialists and auditors are working side by side to improve program performance. Auditors concentrate on comparing a condition against a criterion; evaluators concentrate on what has occurred, estimating what would have occurred without the program and comparing the two situations to determine program effects.
Rebuilding capacity
Authors: General Accounting Office
Published: January 2005

The GAO's transition report to the executive and legislative branches of government, Program Evaluation Issues, began with the section “Why Program Evaluation Is Important,” which is reprinted in Chapter Two of this volume. The report concluded with several sections outlining what would be needed for agencies in the executive branch to rebuild evaluation capacity and what would happen if they do not. The sections constitute a fitting conclusion to this volume.
Investigative strategy in international technical assistance projects
Authors: Chapman David W.
Published: January 2005

Evaluation in international technical assistance programs places a unique set of pressures on the evaluator, which in turn places special demands on the investigative strategies employed.
The relationship between the qualitative and quantitative research traditions
Authors: Reichardt Charles S. , Rallis Sharon F.
Published: January 2005

Differences between the qualitative and quantitative research traditions can be used either to diminish or to enrich the practice of program evaluation.
Qualitative and quantitative inquiries are not incompatible: A call for a new partnership
Authors: Reichardt Charles S. , Rallis Sharon F.
Published: January 2005

The argument that the qualitative and quantitative paradigms are incompatible is not convincing. An enduring and beneficial partnership between qualitative and quantitative researchers is possible.
Is evaluation a mature profession that warrants the preparation of evaluation professionals?
Authors: Worthen Blaine R.
Published: January 2005

Criteria for judging the maturity of any profession are applied to evaluation. Special attention is paid to the question of whether programs for the preparation of evaluation specialists are warranted.
Training evaluators: Unique skills and knowledge
Authors: Mertens Donna M.
Published: January 2005

The skills and knowledge that evaluators need include those borrowed from other disciplines as well as those unique to the field of evaluation. Inclusion of multiple perspectives in evaluator training can help to develop the field and improve the practice of evaluation.
The 1994 directory of evaluation training programs
Authors: Altschuld James W. , Engle Molly , Cullen Carol , Kim Inyoung , Rae Macce Barbara
Published: January 2005

The procedures used to collect information for the Directory of Evaluation Training Programs are described, and the results of the survey are discussed. Tables list the programs identified in the United States, Canada, and Australia.
Judicious application of randomized designs
Authors: Orwin Robert G. , Cordray David S. , Huebner Robert B.
Published: January 2005

Randomized experiments often fail for entirely avoidable reasons. Drawing on examples from the NIAAA Cooperative Agreement program and related literature, the authors present some tools and opportunities for using randomized designs more judiciously.
Confronting ideology and self‐interest: Avoiding misuse of evaluation
Authors: Vroom Phyllis I. , Colombo Marie , Nahan Neva
Published: January 2005

This chapter illustrates the attempt to misuse the evaluation of a complex, large‐scale, highly visible project with many powerful stakeholders and presents the authors' suggestions for countering the misuse.
Brain astrocytes express region‐specific surface glycoproteins in culture
Authors: Barbin Gilles , Katz David M. , Chamak Brigitte , Glowinski Jacques , Prochiantz Alain
Published: January 2005

Astrocytes derived from the mouse brain mesencephalon and striatum regulate neuronal morphogenesis in a region‐specific manner in vitro. To begin defining molecular mechanisms that may underlie this functional heterogeneity, lectin probes were used to compare surface glycoproteins expressed by astrocytes from different brain regions. These experiments demonstrated marked differences in surface glycoproteins depending on the anatomic origin of the astrocytes. In particular, mesencephalic and cerebellar astrocytes express a fucosylated glycoprotein with and apparent molecular weight of 190 kD that is absent or rarely expressed by striatal or cortical astrocytes. These findings raise the possibility that carbohydrate diversity of astrocyte surface molecules may play a role in the heterogeneity of region‐specific neuron‐glial interactions.
Effects of acidic and basic fibroblast growth factors (aFGF and bFGF) on the proliferation and the glutamine synthetase expression of rat astroblasts in culture
Authors: Perraud Frédéric , Besnard François , Pettmann Brigitte , Sensenbrenner Monique , Labourdette Gérard
Published: January 2005

The two fibroblast growth factors called acidic and basic FGF (aFGF and bFGF) show a strong homology (55%) of their amino acid sequence (Esch et al.: Proc. Nat. Acad. Sci. USA 85:6507–6511, 1985). The effects of these factors on the rate of proliferation of rat astroblasts and on the expression of glutamine synthetase activity in cells grown in primary culture were investigated and compared under various culture conditions. In all the experimental conditions used, both growth factors triggered the proliferation of the cells to the same extent and with similar dose dependence. The mitogenic activities of aFGF and bFGF were potentiated similarly by heparan sulfate and by heparin, with a maximum stimulation of about 100% at 100 μg/ml heparin. Treatment of the cells with either of the two factors resulted in identical enhancement of the activity of glutamine synthetase relative to total proteins. These results suggest that both factors act either through the same membrane receptors or through different receptors that mediate nearly identical effects.
Structural complexity of primary cultures of astrocytes as revealed by transverse sections
Authors: Devon Richard M. , Juurlink Bernhard H. J.
Published: January 2005

The tissue architecture of low‐, medium‐, and high‐density primary mouse astroglial cultures was examined in horizontal and transverse planes using the electron microscope. It was found that the low‐density (colony) cultures consisted of a true monolayer, whereas the medium‐ and high‐density (confluent) cultures consisted of anywhere from two to seven overlapping sheets enclosing a substantial intercellular space. The presence of these multiple overlapping sheets in confluent astrocyte cultures should therefore be taken into consideration when interpreting data of cell‐membrane‐related phenomena such as ion fluxes.
Functional plasticity of microglia: A review
Authors: Streit Wolfgang J. , Graeber Manuel B. , Kreutzberg Georg W.
Published: January 2005

The present review summarizes recently acquired data in vivo, which support a role of CNS microglia as a source of defense cells in the CNS capable of carrying out certain immune functions autonomously. We have kept the following discussion restricted to microglial cells and have not included work on the immunological functions of astrocytes, which has been recently reviewed elsewhere (Fontana et al.: Immunological Reviews 137:3521–3527, 1987). Resting microglia are scattered uniformly throughout the CNS forming a network of potential immunoeffector cells, which can be activated by stimuli ranging from peripheral nerve injury over viral infections to direct mechanical brain trauma. The term “activated microglia” is used here to describe proliferating cells that demonstrate changes in their immunophenotype but have not undergone transformation into brain macrophages. Such a transformation can be stimulated by neuronal death but not by sublethal neuronal injury. Microglia may function as antigen‐presenting cells and may thus represent the effector cell responsible for the recruitment of lymphocytes to the brain resulting in an inflammatory reaction. The recent developments in the understanding of microglial cell function may lead to a redefinition of the often cited “immune privilege” of the brain.
Glial cells promote dendritic development in rat sympathetic neurons in vitro
Authors: Tropea Margaret , Johnson Mary I. , Higgins Dennis
Published: January 2005

Many types of glial‐neuronal interactions occur during the development of the nervous system. To determine how such interactions might affect the development of autonomic ganglia, we compared the morphology of embryonic rat sympathetic neurons grown in the absence and in the presence of ganglionic nonneuronal cells in serum‐free medium. Dye injections, electron microscopy, and immunocytochemistry were used to distinguish axons from dendrites. In cultures without nonneuronal cells, most (<80%) sympathetic neurons extended only a single axonal process, and this unipolar state persisted for at least 8 weeks. Coculture with ganglionic nonneuronal cells caused sympathetic neurons to become multipolar and to extend multiple (range 1–17) dendrites. Morphometric measurements made after 1 month of coculture indicated that the amount of dendritic growth that occurred in vitro (mean number of dendrites/cell = 7.5; total dendritic length = 1,050 μm) was similar to that normally occurring during a comparable period in situ. In contrast to its prominent effects on dendritic growth, coculture did not cause chages in the number of axons/neuron or in the uptake of neurotransmitter. Cultures with ganglionic nonneuronal cells were immunostained for antigens present on the surfaces of fibroblasts (Thy‐1.1, fibronectin) and of glia of the peripheral nervous system (laminin). Fewer than 1% of the nonneuronal cells displayed immunoreactivity for fibroblastic antigens; in contrast, ≥99% reacted with antibody to laminin. Moreover, reconstitution experiments revealed that purified populations of laminin‐positive Schwann cells promoted dendritic growth. Fibroblasts and heart cells lacked this activity. These data indicate that glia selectively promote dendritic development in sympathetic neurons maintained in serum‐free medium.
Glial fiber pattern in the developing chicken cerebellum: Vimentin and glial fibrillary acidic protein (GFAP) immunostaining
Authors: Roeling T. A. P. , Feirabend H. K. P.
Published: January 2005

The possible relation betweeen glial fibers and the formation of longitudinal granule cell migration patterns that occur in the cerebellar anlage of the chicken was investigated by immunocytochemistry of vimentin (monoclonal antibody) and glial fibrillary acidic protein (polyclonal antibody against GFAP, PGF) on fixed and unfixed brain tissues. In addition, neuronal development was studied with a monoclonal antibody for neurofilament. Vimentin was present in radial and tangential fibers in the cerebellar anlage during granule cell migration in almost all parts of the anlage. However, no specific topographic relation of vimentin and GFAP to the migration pattern of granule cells was observed. In adults, Bergmann fibers and astroglia were stained with vimentin antiserum and not with GFAP antiserum. Conclusions are that radial fibers do not determine the formation of longitudinal cytoarchitectonic patterns in the chick cerebellum and that vimentin is the main cytoskeletal component of Bergmann fibers and astroglial cells in embryonic and adult chicken cerebellum.
Oligodendrocytes but not astrocytes express apolipoprotein E after injury of rat optic nerve
Authors: Stoll Guido , Mueller Hans Werner , Trapp Bruce D. , Griffin John W.
Published: January 2005

Apolipoprotein E (apoE), a lipid‐binding glycoprotein involved in transport and metabolism of phospholipids and cholesterol, is synthesized and secreted at elevated rates following transection of mature rat peripheral and central nerves. In the peripheral nervous system (PNS) infiltrating macrophages express apoE during Wallerian degeneration. Following injury of the optic nerve (ON) apoE synthesis is significantly stimulated but the apoE‐expressing cells have thus far not been identified. This study used 1 μm and thin cryosections to identify the cellular source of apoE in transected ON. Serial 1 μm frozen sections were stained by avidin‐biotin‐peroxidase complex immunocytochemistry by using a specific antiserum to apoE and by antibodies that identify different cell types: glial fibrillary acidic protein (GFAP) for astrocytes, 2′,3′‐cyclic nucleotide‐3′ phosphodiesterase (CNP) for oligodendrocytes, and ED1 for macrophages. In normal ON both astrocytes and oligodendrocytes were apoE‐positive. One week after ON transection oligodendrocytes accounted for the majority of apoE‐positive cells, while apoE immunoreactivity had disappeared from astroglial cell bodies and processes. In contrast to the PNS only a few ED1/apoE‐positive macrophages were present in ON 7 days after transection. By using immunogold‐labeled ultrathin crysections apoE could be localized in the Golgi apparatus of oligodendrocytes, indicating synthesis by these cells. Our data suggest that oligodendrocyte‐derived apoE protein may participate in the redistribution of myelin lipids after CNS injury.
Dissociation of GFAP intermediate filaments in eae: Observations in the lumbar spinal cord
Authors: Eng Lawrence F. , D'Amelio Fernando E. , Smith Marion E.
Published: January 2005

Acute experimental allergic encephalomyelitis (EAE) in the Lewis rat is a cell‐mediated autoimmune disease of central nervous system myelin. The lesion has been characterized by breakdown of the blood‐brain barrier, edema, and periventricular infiltration of macrophages and lymphocytes. At the early stage of the disease, the astrocytes show a marked increase in immunostaining for glial fibrillary acidic protein (GFAP). A corresponding increase in GFAP content, however, cannot be demonstrated. Electron microscopic examination of the early lesion shows a typical reactive astrocytic response expressed by an enlarged watery cytoplasm, particularly at the level of the processes surrounding neurons and blood vessels and in the neuropil itself. The astroglial processes contain numerous glycogen particles (aggregates and single particles). Glial filaments are also conspicuous and are arranged in small bundles or loose thin filaments adjacent to the bundles. The glial filaments that normally appear as tight bundles have expanded and appear less dense. We suggest that the increase in GFAP immunostaining of the astrocytes in the early lesion is due in part to edema, which causes dissociation of the filaments and thereby exposes more antigenic sites to the antibodies.
Expression of viral and myelin gene transcripts in a murine CNS demyelinating disease caused by a coronavirus
Authors: Jordan Craig A. , Friedrich Victor L. , Godfraind Catherine , Cardellechio Christine B. , Holmes Kathryn V. , Dubois‐Dalcq Monique
Published: January 2005

C57BI/6N mice develop a CNS demyelinating disease when inoculated intracranially at 4 weeks of age with the A59 strain of mouse hepatitis virus (MHV‐A59). In order to explore the virus‐host interactions, the histological features of the demyelinating disease were correlated with the spatial and temporal distribution of viral transcripts and the expression of oligodendrocyte‐specific genes (myelin basic protein, proteolipid protein, myelin‐associated glycoprotein, and 2′, 3′ cyclic nucleotide 3′‐phosphohydrolase) in the spinal cord of diseased mice. Three distinct phases in the disease were identified. In the first phase, 1 week postinfection (1 WPI), virus replication was widespread in both gray and white matter but was preferentially occurring in glial cells. In the ventral and dorsal root zones where viral transcripts were most abundant, all myelin gene transcripts were decreased before demyelination was seen. During the second phase of the disease (2–3 WPI), viral transcripts decreased in abundance and became restricted to the white matter. Numerous demyelinating lesions were observed and were characterized by inflammatory cells, paucity of oligodendrocytes, and a profound decrease of all myelin gene transcripts. In the third phase of the disease (4–6 WPI) no viral transcripts were detected, and remyelination began. In the lesions and the tissue surrounding them, transcripts of all myelin genes increased to levels above normal. The increased expression of myelin gene transcripts occurred in a synchronized manner and with a cellular distribution reminiscent of that seen in developmental myelination. These molecular events correlated with efficient remyelination and clinical recovery in this murine demyelinating disease.
In situ demonstration of mature oligodendrocytes and their processes: An immunocytochemical study with a new monoclonal antibody, Rip
Authors: Friedman B. , Hockfield S. , Black J.A. , Woodruff K.A. , Waxman S.G.
Published: January 2005

This paper introduces “Rip” a monoclonal antibody that produces relatively complete staining of oligodendrocytes and their processes in the adult central nervous system (CNS). The distribution of Rip immunoreactivity coincides with that of myelinated axons in both the spinal cord and the cerebellum. In addition, doubleimmunolabeling experiments demonstrate that Rip stains processes containing myelin basic protein but does not stain processes that express glial fibrillary acidic protein. These results indicate that Rip selectively stains oligodendrocytes but not astrocytes. Moreover, individual Rip‐stained oligodendroglial somata and their cytoplasmic processes were observable at both the light microscopic and electron microscopic level when the staining of myelin was reduced. This was accomplished by omitting detergents from antibody incubation steps. Rip‐stained oligodendrocytes have multiple processes of varying thickness, some of which end in close proximity to myelin sheaths. These immunostained profiles, reminiscent of those observed in oligodendrocytes stained by Golgi methods, are unique to Rip and indicate that its immunoreactivity is distinct from that of existing serological markers for oligodendrocytes.
Glial hyaluronate‐binding protein in Wallerian degeneration of dog spinal cord
Authors: Bignami Amico , Mansour Hussein , Dahl Doris
Published: January 2005

Wallerian degeneration of spinal cord dorsal columns was produced in three dogs by unilateral extradural dorsal rhizotomy at the lower thoracic level. The spinal cord was studied 1 month, 2 months, and 3 months after surgery. Transverse cryostat sections at the site of rhizotomy and at the mid‐thoracic level were stained by indirect immunofluorescence with antibodies to the glial fibrillary acidic protein (GFAP) and to the glial hyaluronate‐binding protein (GHAP). GHAP immunoreactivity was almost unchanged in the degenerated dorsal column 1 month after rhizotomy. After 2 and 3 months, staining with GHAP antibodies was markedly decreased in the gliosed dorsal column at the site of rhizotomy, but it still persisted at the mid‐thoracic level. It is concluded that GHAP persists for long periods of time in dorsal columns undergoing Wallerian degeneration, a finding consistent with its putative role as a nonpermissive substrate preventing nerve regeneration in CNS white matter.
Expression of high molecular weight astroglial extracellular proteins is altered by growth environment
Authors: Quarless Shelley A. , Lam Dominic M.K.
Published: January 2005

Conditioned medium from primary rat cortical glia was analyzed with respect to the composition of the secreted high molecular weight protein species. Developmental characteristics of astroglia are affected by growth in the presence and absence of serum. These growth conditions had a pronounced effect on the extracellular protein profile, cellular morphology, and cell substratum adhesion.

Cells cultured in defined serumless medium did not express certain proteins expressed in the presence of serum but rather synthesized proteins specifically stimulated by the defined serumless environment. A morphological change from flat amorphous to a contracted fibrous network having an increased affinity for self‐self cellular adhesion rather than adhesion to the surface of the tissue culture dish was also stimulated by the defined serumless medium environment.

A comparison of the extracellular proteins secreted by the rat C6 glioma and the rat PC12 cell demonstrated the cell‐specific nature of the primary glial proteins.
Comparative immunohistochemical study of glial filament proteins (glial fibrillary acidic protein and vimentin) in goldfish, octopus, and snail
Authors: Cardone Beatrice , Roots Betty I.
Published: January 2005

Glial fibrillary acidic protein (GFAP) and vimentin proteins are known to be component proteins of glial filaments in the CNS of many vertebrates. The nature of the filaments present in the glial cells of the goldfish optic tectum and in the CNS of two members of the Mollusca (Helix pomatia and Octopus vulgaris) were investigated using immunocytochemical localization of monoclonal antibodies to GFAP and vimentin. Immunoblots visualized by the alkaline phosphatase method showed cross‐reactive protein bands to GFAP and vimentin antibodies in total brain homogenates of the goldfish, octopus, and snail. Immunofluorescence staining of the goldfish optic tectum showed GFAP immunoreactivity, primarily in the ependymal cell processes. Immunogold labelling at the ultrastructural level verified that GFAP antibodies were bound to glial filaments. Immunolabelling of the optic lobe of Octopus vulgaris and the cerebral ganglia of Helix pomatia suggests that a protein exhibiting antigenic properties similar to GFAP is a component protein in the filaments of the protoplasmic and filamentous glia randomly distributed throughout the CNS. Unlike anti‐GFAP antibodies, which stained relatively specific to filaments, vimentin staining in the CNS tissues of the three organisms studied did not appear to be exclusive to filamentous structures. As vimentin protein has been shown, in previous studies as well as our own, to exist in many tissue types, this suggests that it does not appear to be confined to glial filaments but is shared with other subcellular components. The proteins GFAP and vimentin which are thought to be well conserved in vertebrate evolution also appear to be expressed in the nervous system of some lower organisms.
Sequence of tissue responses in the early stages of experimental allergic encephalomyelitis (EAE): Immunohistochemical, light microscopic, and ultrastructural observations in the spinal cord
Authors: D'Amelio Fernando E. , Smith Marion E. , Eng Lawrence F.
Published: January 2005

Experimental allergic encephalomyelitis (EAE) was induced in adult Lewis rats with purified guinea pig CNS myelin and Freund' adjuvant. As soon as the very earliest clinical signs appeared the animals were perfused with fixatives and the spinal cord analyzed by electron microscopy, silver methods, and immunocytochemistry.

Our findings suggest that in the early stages of EAE a sequence of events can be traced, although these events frequently overlap. The earliest morphological change appears to be astrocytic edema in both the cell body and processes. Increased amounts of glycogen particles and dispersion of glial filaments are prominent. These changes seem to occur just prior to the time when inflammatory cells begin to penetrate the capillary walls. Invasion of the neuropil mainly by macrophages and lymphocytes closely follows. Both macrophages and microglia seem to participate in phagocytosis of oligodendrocytes and myelin. Demyelination, however, is not a prominent feature at this early stage.
Neuron–glial interactions involved in the regulation of glutamine synthetase
Authors: Mearow Karen M. , Mill John F. , Freese Ernst
Published: January 2005

Cocultures of rat cortical astrocytes with cerebellar granule cell neurons, but not a variety of other cell types tested, resulted in an induction of glutamine synthetase (GS) mRNA over the basal levels expressed in pure astrocyte cultures. This induction involved both contact‐ and noncontact‐mediated events and may be a result of astroglial differentiation promoted by interactions with the primary neurons. Astrocytes grown in the presence of the granule neurons (but not the other cell types tested) exhibited a more complex, process‐bearing morphology typical of more differentiated cells. In addition, glial cell proliferation was inhibited not only by the presence of live granule cells, but also by fixed neurons and neuronal membranes. Under the same experimental conditions, GS mRNA was increased (two‐ to threefold) compared with the expression observed in pure astrocyte cultures. Because of the role of GS in glutamate metabolism and the influence of the glutamatergic granule neurons on glial GS mRNA levels, the effect of exogenous glutamate was examined. The addition of 100 μM glutamate to the culture medium resulted in an increase in GS mRNA in the astrocyte cultures similar to that observed in the cocultures, where the addition of glutamate did not further increase GS mRNA levels. These results provide further evidence for the importance of neuron–glial interactions in the regulation of glial gene expression.
Basic fibroblast growth factor (bFGF) and rat C6 glioma cells: Regulation of expression, absence of release, and response to exogenous bFGF
Authors: Westermann Reiner , Unsicker Klaus
Published: January 2005

Basic fibroblast growth factor (bFGF) is a potent mitogen for several types of cells, including glial cells, which also seem to express bFGF. We have used rat C6 glioma cells as a model system to study the expression and release of bFGF by glioma cells, as well as the effects of exogenous bFGF on these cells. We have shown that C6 cells, express 18 kD bFGF and several higher molecular weight immunoreactive forms. The expression of bFGF could be induced by a factor present in fetal calf serum. Subsequent to its initial appearance, bFGF is regulated in a cell density‐dependent manner. Neither bFGF‐like immunoreactive material, nor bFGF‐like neurotrophic activity were found to be released by C6 cells. Exogenously applied bFGF changed C6 cell morphology similar to cyclic AMP induced alterations but had no significant influence on C6 cell proliferation and biochemical differentiation. From these results we conclude that bFGF in C6 cells might act as an endogenous (not autocrine) mitogen. Possible roles for bFGF in glial cells are discussed.
Double‐labeling in situ hybridization analysis of mRNAs for carbonic anhydrase II and myelin basic protein: Expression in developing cultured glial cells
Authors: Ghandour M. S. , Skoff R. P.
Published: January 2005

We applied in situ hybridization to analyze the location and the developmental changes in the distribution of the transcripts for carbonic anhydrase II (CAII) and myelin basic protein (MBP) in mouse primary cultured glial cells. Both mRNAs were localized to the oligodendrocyte using double‐labeling in situ hybridization. No evidence for CAII transcripts in astrocytes was obtained, indicating that CAII is expressed only by oligodendrocytes in normal rodent glia. As early as 48 h after plating, CAII and MBP mRNAs are present in a few, small round cells. Message is present 2–4 days before levels of these proteins can be detected in similar primary glial cultures.

The intensity of labeling for MBP and CAII mRNA positive cells increases significantly during the second week but then decreases after the end of the third week.

Only the oligodendrocyte perikaryon and a few processes are positive during the first week. In contrast, at 14 days, a large number of cell processes in addition to the cell bodies are heavily stained for both mRNAs. Both mRNAs could be detected far away from the cell body, up to 250 μm in some cell processes. Some segments on a cell process accumulate higher levels of mRNA than other areas. These areas may correspond to the accumulation of free ribosomes and to starting points for the membrane sheets elaborated by cultured oligodendrocytes. The developmental profile for timing and distribution of these two messages mimics closely their in situ pattern.
Role of glia in K+ and pH homeostasis in the neonatal rat spinal cord
Authors: Jendelová Pavla , Syková Eva
Published: January 2005

Stimulation‐evoked transient changes in extracellular potassium ([K+]e) and pH (pHe) were studied in the neonatal rat spinal cords isolated from 3–13‐day‐old pups. In unstimulated pups the [K+]e baseline was elevated and pHe was more acid than that in Ringer's solution (3.5 mM K+, pH 7.3–7.35). The [K+]e and pHe in 3–6‐day‐old pups was 3.91 ± 0.12 mM and pHe 7.19 ± 0.01, respectively, while in 10–13‐day‐old pups it was 4.35 ± 0.15 mM and 7.11 ± 0.01, respectively. The [K+]e changes evoked in the dorsal horn by a single electrical stimulus were as large as 1.5–2.5 mM. Such changes in [K+]e are evoked in the adult rat spinal cord with stimulation at a frequency of 10–30 Hz. The maximal changes of 2.1–6.5 mM were found at a stimulation frequency of 10 Hz in 3–6‐day‐old animals. In older animals the [K+]e changes progressively decreased. The poststimulation K+‐undershoot was found after a single stimulus as well as after repetitive stimulation.

In 3–8‐day‐old pups, the stimulation evoked an alkaline shift, which was followed by a smaller poststimulation acid shift when the stimulation was discontinued. In pups 3–4‐days‐old the stimulation evoked the greatest alkaline shifts, i.e., by as much as 0.05 pH units after a single pulse and by about 0.1 pH units during stimulation at a frequency of 10 Hz. In 5–8‐day‐old pups, the alkaline shift became smaller and the poststimulation acid shift increased. Stimulation in 10–13‐day‐old pups produced an acid shift of 0.03–0.07 pH units, which was preceded by a scarcely discernible alkaline shift. MgCl2 (20 mM) reversibly reduced the alkaline but not the acid shifts by 50–60%. Bath application of the carbonic anhydrase inhibitor acetazolamide had no effect on the alkaline shift, while the acid shift decreased by 70–80%. The superfusion of the cord with 10 mM KCl resulted in acid shifts of 0.10–0.14 pH units.

We conclude that the [K+]e ceiling level and the character of pHe transients in the spinal cord are closely related to gliogenesis. Our results suggest that glial cells buffer the activity‐related [K+]e increase and alkaline pHe shifts in the extracellular space.
Biochemical and ultrastructural study of glycogen in cultured astrocytes submitted to the convulsant methionine sulfoximine
Authors: Hevor T. K. , Delorme P.
Published: January 2005

The convulsant methionine sulfoximine is a potent glycogenic agent in the central nervous system of rodents in vivo. This investigation was undertaken to look for the basic mechanism underlying this property. Astrocytes were cultivated from newborn rat neopallium and glycogen was studied by both biochemical and ultrastructural methods. When the astrocytes were incubated in a medium containing 5.55 mM glucose, methionine sulfoximine (0.55 mM) induced a significant increase in their glycogen content. Glucose content did not change in astrocytes, but it diminished in the medium in all cases. When the decrease in glucose level in the medium was limited, the same glycogenic effects of methionine sulfoximine were observed, but the glycogen contents were higher. The augmentation of the concentration of the convulsant enhanced its glycogenic effect, but this was not directly dose dependent. When the flat and polygonal astrocytes were transformed into process‐bearing astrocytes by dibutyryl cyclic AMP methionine sulfoximine always induced an increase in glycogen content. In this case, the values of glycogen contents were lower. In electron microscopy, no glycogen particles were present in the astrocytes even after methionine sulfoximine treatment, contrary to the case in vivo. These results show that the convulsant does not need the presence of neuronal cells to induce glycogen accumulation and that astrocytes may be the direct cell targets. The apparent discrepancy between the biochemical and ultrastructural data is probably due to the relatively low concentration of glycogen in cultured astrocytes.
Quisqualate‐induced excitotoxic death of glial cells: Transient vulnerability of cultured astrocytes
Authors: Haas Jitka , Erdö Sándor L.
Published: January 2005

The cytotoxic effect of quisqualate, a potent excitatory amino acid (EAA), was examined in purified astrocyte cultures obtained from neonatal rat cerebral cortex and grown in a serum‐free, defined medium (G5). Excitotoxicity was evaluated by phase contrast microscopy and quantified by the measurement of lactic dehydrogenase (LDH) activity released from the damaged cells into the culture medium. Quisqualate evoked not only osmotic swelling, but also cytotoxic cell death of cultured astrocytes. The vulnerability of cells was restricted to a period between day 4 and 8 in subculture, with a maximal sensitivity on day 7. The present findings indicate that not only neurons, but also glial cells may exhibit excitotoxic vulnerability. The vulnerability to quisqualate appears to be a transient phenomenon, at least in cultured astrocytes.
Glial cell lineages in the neural crest
Authors: Douarin Nicole Le , Dulac Catherine , Dupin Elisabeth , Cameron‐Curry Patrizia
Published: January 2005

We have been studying how and when the different peripheral glial cell lineages individualize during avian embryonic development. Three different and complementary experimental approaches were used for this purpose: (1) the quail/chick chimera system allowed the tracing in vivo of the origin of the various types of peripheral glial cells (Schwann cells of nerves, satellite glial cells of sensory and autonomic ganglia, and enteric glial cells), and the analysis of the non‐neuronal cell population of ganglia; (2) characterisation of early cell‐type specific markers that discriminate between the different glial cell subpopulations; and (3) analysis of the progeny of neural crest cells in clonal cultures. As a result of these approaches, two novel glial‐specific markers, expressed earlier than any previously described myelin components, have been identified and partly characterised. The divergence of glial and neuronal cell lineages is a process that is not completely terminated during the phase of neural crest migration. Whereas some cells are apparently already totally committed to a glial fate at this stage, others retain dual neuronal/glial potentialities.
Remyelination of demyelinated rat axons by transplanted mouse oligodendrocytes
Authors: Crang A. J. , Blakemore W. F.
Published: January 2005

The injection of the gliotoxic agent ethidium bromide (EB) into spinal white matter produces a CNS lesion in which it is possible to investigate the ability of transplanted glial cells to reconstruct a glial environment around demyelinated axons. This study demonstrates that transplanted mouse glial cells can repopulate EB lesions in rats provided tissue rejection is controlled. In X‐irradiated EB lesions in cyclosporin‐A‐treated rats, mouse oligodendrocytes remyelinated rat axons and, together with mouse astrocytes, re‐established a CNS environment. When transplanted into nonirradiated EB lesions in nude rats, mouse glial cells modulated the normal host repair by Schwann cells to remyelination by oligodendrocytes. In both X‐irradiated and non‐irradiated EB lesions, transplanted mouse glial cells behaved similarly to isogenic rat glial cell transplants (Blackemore and Crang Dev Neurosci, 1988;10:1–10; J Neurocytol, 1989;18:519–528). These findings indicate that the cell‐cell interactions involved in reconstruction of a glial environment are common to both mouse and rat.
Excitatory amino acid receptors in primary cultures of glial cells from the retina
Authors: María López‐Colomé Ana , Romo‐De‐Vivar Mónica
Published: January 2005

Binding of 3H‐L‐aspartate to membranes from retinal glial cells in primary culture was characterized. Binding kinetics showed a saturable, reversible binding to three populations of sites with KB = 40,200, and 1,300 nM. The first two were present at 1 day in vitro (DIV), whereas the latter two were observed at 12 DIV. The possibility of the 40 nM site being neuronal cannot be discarded, since some neurons are present at 1 DIV. In 12 DIV cultures, the presence or absence of sodium determined two different pharmacological patterns, comparable to those described for electrogenic glutamate transport in Müller cells, and QA metabotropic receptors in astrocytes, respectively. Results suggest that, as has been shown for some receptors in nerve tissue, the properties of glial cell receptors undergo age‐dependent changes. In turn, this could be related to changes in the function of neurotransmitter substances during development.
High conductance anion channel in Schwann cell vesicles from rat spinal roots
Authors: Quasthoff Stefan , Strupp Michael , Grafe Peter
Published: January 2005

Potassium uptake, possibly together with chloride, is one of the presumed functions of Schwann cells in the peripheral nervous system. However, the presence of chloride channels has not been demonstrated in adult Schwann cells. We present here a new method which allows single channel recordings to be made from Schwann cells in situ without enzymatic treatment. Isolated rat spinal roots were split mechanically into several bundles. Within about 30 min after this procedure small belb‐like vesicles (∼20–30 μm in diameter) with a clean surface appeared at the edges of the fibre bundles. Immunofluorescence microscopy with a surface marker for Schwann cell membranes (monoclonal antibody O4) revealed that the vesicles originate from Schwann cells. In standard patch clamp recordings with symmetrical bath and pipette solutions (excised inside‐out configuration) an anion channel with the following characteristics was mainly observed: (1) single channel slope conductance of 337 ± 5 pS in 125 mM KCl and 209 ± 6 pS in 125 mM K+ methylsulphate; (2) ion permeability ratio: PCl/PK/Pgluconate = 1/0.12/0.06; (3) linear current‐voltage relationship (range ± 60 mV) and (4) voltage‐ and time‐dependent inactivation (the channel was most active at potentials ± 20mV). Pharmacologically, the channel was completely blocked with zinc (1 mM) and barium (10 mM). A similar anion channel, showing characteristics 1 – (4), has been described in cultured Schwann cells of newborn rats (Gray et al., 1984). We now demonstrate that this channel is also present in adult Schwann cells in situ.
Amoeboid and ramified microglia: Their interrelationship and response to brain injury
Authors: Leong Seng‐Kee , Ling Eng‐Ang
Published: January 2005

Rio‐Hortega's hypothesis that transietly appearing amoeboid microglia might become ramified microglia in the adult and that the latter could differentiate into brain macrophages in the event of brain damage could not be proved because of inherent limitations in existing techniques. The present investigation used a novel method of labelling the rat supraventricular amoeboid microglia with an enduring fluorescet marker, rhodamine B isothiocyanate, introduced intraperitoneally. Observation of their subsequent development showed that they became transformed into the ramified microglia. Both te amoeboid and ramified microglia were OX‐42 positive, indicating their macrophage/monocyte lineage. Other microglia in the cerebral neocortex, which were also OX‐42 positive, were not derived from any of the rhodamine‐labelled cells. Rhodamine‐labelled cells, which were OX‐42 positive, appeared at all lesioned sites, and such were most likely blood derived monocytes. The antigeicity of the ramified microglia became elevated when rhodamine B isothiocyaate was present intracellularly and even more so with the presence of a earby intracerebral stab wound. © 1992 Wiley‐Liss, Inc.
Estradiol promotes cell shape changes and glial fibrillary acidic protein redistribution in hypothalamic astrocytes in vitro: A neuronal‐mediated effect
Authors: Torres‐Aleman Ignacio , Rejas Maria Teresa , Pons Sebastian , Garcia‐Segura Luis Miguel
Published: January 2005

We have previously shown that in hypothalamic mixed neuronal‐glial cultures both astrocytic shape and distribution of glial fibrillary acidic protein (GFAP) are modified by estradiol. In the present study, we have investigated whether or not the presence of neurons is necessary for these hormonal effects. In mixed neuronal‐glial hypothalamic cultures the proportion of process‐bearing GFAP‐immunoreactive cells was significantly increased after treatment for 30 min with 10−12 M 17β estradiol. This effect was present for at least 1 day and was reverted by incubating the cells in estradiol‐free medium. Estradiol incubation resulted in a progressive differentiation of GFAP‐immunoreactive cells from a flattened epithelioid morphology to bipolar, radial, and stellate shapes. This effect was not observed in pure hypothalamic glial cultures. Furthermore, incubation of hypothalamic glial cells with medium conditioned by estradiol‐treated mixed hypothalamic cultures did not affect the shape of GFAP‐immunoreactive astrocytes. In contrast, addition of hypothalamic neurons, but not cerebellar neurons or fibroblasts, to established hypothalamic glial cultures affected the development of estradiol sensitivity in astrocytes. These results indicate that estradiol induction of shape changes in hypothalamic astrocytes is not only dependent on the presence of hypothalamic neurons, but that physical contact between astrocytes and neurons is necessary for the manifestation of the effect of this hormone. © 1992 Wiley‐Liss, Inc.