bluuebunny/crossref_metadata_2025 huggingface dataset:
Behavioral and physiological response of juvenile sooty mangabeys to reunion with their mothers following a year's absence
Authors: Gust Deborah A. , Gordon Thomas P. , Brodie Annr R. , McClure Harold M.
Published: January 2005

The return of 6 juvenile manabey monkeys to their social group following an absence of a year resulted in increased basal cortisol secretion for both the offspring and the mothers and in significant decrements in the absolute number of lymphocyte subsets for the offspring. Six 9‐month‐old sooty mangabeys were removed from their socially housed mothers, subsequently peer housed, and returned to the maternal social group 1 year later. Offspring showed a significant increase in cortisol levels 24 hr following reunion (48 ± 6%) and this difference persisted through 1 month, while the mothers showed a significant increase only at the 24‐hr sample point (18 ± 3%). Moreover, the offspring, but not the mothers, showed a significant decrease in lymphocyte subsets which were evident through the 1‐month sample point. Behavioral data revealed a significant positive correlation between the percent of total scan samples offspring were with their mothers (proximity, contact, huddle) the day of return and the offspring's percent change from baseline in total T cells 24 hr later, r = 0.84. All mother‐offspring pairs with the exception of one exhibited frequent affiliative behaviors toward one another by 6 days following the return. These data demonstrate that the reunion of juvenile mangabeys with their mothers after a year's absence is an acute stressor for the mothers and a relatively longer term stressor for the offspring, and that behavioral interactions which characterize the return of individual subjects to the natal group can predict acute physiological responses. © 1992 Wiley & sons. Inc.
Ultrasonic vocalization responses of rat pups to acute separation and contact comfort do not depend on maternal thermal cues
Authors: Hofer Myron A. , Brunelli Susan A. , Shair Harry N.
Published: January 2005

In order to assess the importance of maternal thermal cues in controlling the acute USV responses of rat pups to contact with her body (the contact comfort response) and to separation from her, we drastically altered maternal temperature by inducing severe hypothermia so that maternal rectal and flank temperatures averaged more than 20°C below normal and 10°C below ambient levels during testing. Isolated 12‐ to 13‐day‐old pups showed reductions in USV when these cold dams were presented and brisk USV accelerations when the cold dams were removed from the test chamber. These responses closely resembled those of other pups tested with warm (36°C) anesthetized dams. No significant differences were found in pups' USV contact comfort responses to cold and warm dams. For acute separation, prior maternal thermal properties and other factors were found to modulate the relative intensity of the marked USV increase elicited by this event © 1993 John Wiley & Sons, Inc.
Individual differences in the visual attention of human infants: Further evidence for separate sensitization and habituation processes
Authors: Peterzell David H.
Published: January 2005

How many and what kinds of processes mediate infant visual attention? Are they influenced by stimulus “complexity?” Analyses were performed on visual fixation data from ninety 4‐month‐old infants; the time each infant spent looking at a black and white checkerboard pattern containing either 4 × 4, 12 × 12, or 20 × 20 checks per picture was measured for eight 10‐s trials, with 10‐s interstimulus intervals (Kaplan & Werner, 1986). Correlational and factor analyses revealed one significant source of individual variability (or factor) in the 4 × 4 data, and two significant sources in the 12 × 12 and 20 × 20 data. One factor gained strength over progressive trials and accounted for decreases in looking time. A second factor gained strength over the first few trials, then lost strength over the remaining trials, and accounted for initial increments in looking time. The two factors are consistent with a dual‐process model of infant response dynamics; the first may represent habituation, a decremental process, and the second may represent sensitization, an incremental process that is activated by “complex” stimuli. © 1993 John Wiley & Sons, Inc.
The ontogeny of ultrasonic vocalizations and other behaviors in male jimpy (jp/Y) Mice and their normal male littermates
Authors: Bolivar Valerie J. , Brown Richard E.
Published: January 2005

Jimpy (jp/Y) male mice have a sex‐linked mutation which results in dysmyelination throughout the CNS, causing tremors and behavioral abnormalities. These mice rarely live past 30 days of age. Due to the sex‐linked nature of this mutation, both jimpy and normal male pups occur within the same litter. We examined the early behavioral development of these mice by recording their motor behaviors, including slight movement, locomotion and grooming, and their ultrasonic vocalizations (UVs) at 2‐day intervals from 2‐20 days of age. Jimpy males weighed less than their normal littermates and reached developmental milestones at a later age. They produced fewer UVs than their normal male littermates from 2–8 days of age, after which UVs ceased almost completely in both groups of mice. Jimpy mice spent less time engaged in coordinated motor activities (locomotion and grooming) than normal littermates, and more time engaged in slight movement or remaining inactive. On three of the behavioral measures used (UV production, slight movement, and inactivity) differences were evident early in development (Day 2 postpartum), whereas differences on the other measures (locomotion, grooming) were not evident until later in the developmental period. Our results indicate the importance of using multiple behavioral measures when examining the functional effects of myelin deficiency.© 1994 John Wiley & Sons, Inc.
Learning of suckling odors by newborn rabbits declines with age and suckling experience
Authors: Kindermann Ute , Hudson Robyn , Distel Hans
Published: January 2005

After being nursed just once for 4‐5 min by an artificially scented doe, newborn rabbits show the full pattern of nipple‐search behavior when placed on a fur scented with the same odor as their mother. It was the aim of the present study to test whether such rapid learning is dependent on age. In Experiment 1 in which normally raised pups were nursed by a scented doe either on Days 1, 3 or 5, conditionability was found to decline markedly by postnatal Day 5. In Experiment 2 conditionability was maintained in pups deprived of suckling experience by bottle feeding from Days 1–4, but not in hand‐raised pups allowed to search on a doe for 4 min daily without milk intake. Possible mechanisms underlying the decline in conditionability to suckling odors, as well as the potential functional significance of this early learning for immediate postnatal and later life are discussed.© 1994 John Wiley & Sons, Inc.
Intracerebroventricular injection of renin in the neonatal rat reveals a precocious sodium appetite that is dissociated from renin‐aroused thirst
Authors: Leshem Micah , Canho Sonia Del , Epstein Alan N.
Published: January 2005

Previous research on the ontogeny of sodium appetite in the rat has shown that sodium deficit first engenders sodium intake at 12 days of age, whereas direct stimulation of the brain renin—angiotensin system by intracranial injection of renin increases intake of NaCl solution as early as 3 days postnatally. Similar activation of brain angiotensin also increases thirst, so that the specificity of the precocious sodium intake remains undetermined. In this article we report experiments that dissociate neonatal renin‐evoked sodium appetite and thirst, and establish the specificity of the appetite. Our findings confirm that sodium appetite can first be discerned at 3 days of age, and show that it rapidly develops until 12 days of age. During this developmental window, renin‐evoked sodium appetite is dissociated from thirst because (a) NaCl is preferred to water, (b) the appetite develops faster than thirst, and (c) 3‐day‐old renin‐stimulated pups will avidly lick dry NaCl. These results show that activation of brain angiotensin in the 3‐day‐old rat pup evokes a precocious and specific sodium appetite.© 1994 John Wiley & Sons, Inc.
An observational study comparing continuous subcutaneous insulin infusion (CSII) and insulin glargine in children with type 1 diabetes
Authors: Schiaffini Riccardo , Ciampalini Paolo , Spera Sabrina , Cappa Marco , Crinó Antonino
Published: January 2005

Objective

The advantages of continuous subcutaneous insulin infusion (CSII) or insulin glargine have been demonstrated both in adult and paediatric diabetic patients; however, as no data comparing these two approaches during childhood are available, we have examined the efficacy of these two intensive approaches.

Research Design and Methods

We retrospectively evaluated data from 36 diabetic children, who had changed their previous insulin regimen [with isophane insulin (NPH) at bedtime] because of HbA1c levels >8.0%. Twenty patients underwent CSII, while the other 16 (significantly younger for age) started insulin glargine at bedtime.

Results

At 6 and 12 months, CSII‐treated patients showed a significant reduction in HbA1c values from 8.5 ± 1.8 to 7.4 ± 1.1% and to 7.6 ± 1.2%, respectively. The insulin requirement significantly decreased from 0.93 ± 0.2 IU/kg to 0.73 ± 0.2 IU/kg of body weight and to 0.74 ± 0.15 IU/kg of body weight, respectively, while no significant differences were observed for BMI SDS, fructosamine and severe hypoglycaemic events. The patients treated with glargine showed a small decline in HbA1c values from 8.9 ± 1.7 to 8.3 ± 0.9% (not significant) in the first 6 months of treatment and to 8.2 ± 0.9% after 12 months.

Conclusion

The basal insulin supplementation can be supplied effectively in children with type 1 diabetes by either CSII or insulin glargine. As previously reported for adults, it is confirmed that CSII is the best current intensive approach aimed to the improvement of glycaemic control. Copyright © 2004 John Wiley & Sons, Ltd.
Evaluating program impact: A time to cast away stones, a time to gather stones together
Authors: Bryk Anthony S.
Published: January 2005

Although for many thoughtful observers recent experiences with evaluating the impact of programs have proved disappointing, there is considerable disagreement on both what constitutes the problem and what represents a solution.
Organizational control: Monitoring ongoing programs
Authors: Schroder Harold M.
Published: January 2005

All programs contain formal or informal monitoring functions which influence organizational learning and development.
Evaluation perspectives in the Law Enforcement Assistance Administration
Authors: Swisher Ralph B.
Published: January 2005

Social program evaluations need to produce more information of greater relevance and utility. LEAA is looking for ways to do that.
Assessment center monitoring
Authors: Moses Joseph L.
Published: January 2005

The difference between effective and ineffective assessment‐center operations lies in the importance attached to monitoring efforts.
Quality control in technical military training programs
Authors: McClelland William A. , Wagner Harold
Published: January 2005

During a quarter century of research and development in military training and education, the Human Resources Research Organization (HumRRO) has encountered many problems in the evaluation of military instructional systems.
Monitoring the state‐federal rehabilitation program
Authors: Barry John R.
Published: January 2005

The present reporting and monitoring systems in state‐federal rehabilitation programs contain problems in the collection and use of data, suggesting needed changes.
Three approaches to monitoring mental health services
Authors: Windle Charles , Sharfstein Steven S.
Published: January 2005

To improve federal monitoring, better knowledge of the impacts and costs of optional approaches is needed.
The assessment of scholarship
Authors: Jones Lyle V.
Published: January 2005

It remains desirable to use several distinct measures of scholarship. If these measures converge to a single interpretation, confidence in that interpretation is justified.
Quantitative training for evaluation research
Authors: Fienberg Stephen E.
Published: January 2005

Inextricably entwined with research methods are the quantitative skills required to develop, manage, and analyze the complex data sets that almost always characterize evaluation projects. Büt is there any common core of quantitative skills that all evaluation researchers should possess? And should quantitative skills be taught within the context of an evaluation research program?
The primacy of values and ideologies in human services evaluation
Authors: Wolfensberger Wolf
Published: January 2005

Only an evaluation design that encompasses genuinely universal principles can be applied to services in different categories and still produce valid comparisons.
The organizational imperative
Authors: Gerhard Ronald J.
Published: January 2005

Evaluation has generally incorporated the scientific method into its paradigms. However, systems thinking, which considers not only individual programs but also the relationship of programs and their overall direction, is just beginning to emerge in the field.
Evaluating mental health service systems: A case in retrospect
Authors: Wooldridge Ronald J. , Bernard Jack A.
Published: January 2005

Small‐scale program evaluations cannot discriminate between the flaws of the program and the flaws of the superordinate system.
Service delivery assessment: Qualitative evaluations at the cabinet level
Authors: Hendricks Michael
Published: January 2005

An innovative new evaluation unit in the U.S. Department of Health and Human Services is regularly briefing the Secretary on the services delivered to clients at the local level.
Public policy and psychotherapy: Can evaluative research play a role?
Authors: Saxe Leonard
Published: January 2005

The author reviews efforts of the 96th Congress to use evaluation data in considering whether to change policies about reimbursement for psychotherapy services.
How the committee built the standards
Authors: Anderson Scarvia B.
Published: January 2005

Over the course of several years, the ERS Standards Committee debated the need for standards for program evaluation, discussed and drafted standards, revised the content of each, and finally delivered the document published here. The task was not always easy.
An assessment of the utility of the ERS standards
Authors: Cordray David S.
Published: January 2005

If the ERS Standards for Program Evaluation are to improve evaluation practices, proposal review, prerelease critiques, summative assessments, and secondary analysis may be necessary.
The stakeholder approach to evaluation: Origins and promise
Authors: Weiss Carol H.
Published: January 2005

The promise of the stakeholder approach to evaluation lies in its potential to overcome shortcomings identified by critics: that evaluation is too narrow, unrealistic in its standards for success, unfair to program staff and participants, and irrelevant to decision makers.
Organizational contexts for evaluation
Authors: Louis Karen Seashore
Published: January 2005

The organizational setting of an evaluation has a significant impact on the resources available for managing individual evaluation projects.
How we think about evaluation
Authors: House Ernest R.
Published: January 2005

Even our most complex, scientific conceptions of evaluation are strongly influenced by underlying, deep‐seated metaphors.
Should evaluation become implementation?
Authors: Browne Angela , Wildavsky Aaron
Published: January 2005

Can the same person be responsible for evaluation and implementation? What are the limits of self‐evaluation?
Microcomputers in schools: The video case study as an evaluation tool
Authors: Ingle Henry T.
Published: January 2005

Our relatively limited experience with the use of microcomputers in education and the small number of educators with direct hands‐on experience with the technology argue for the use of innovative research methods. Video case studies can serve a useful purpose.
Evaluation synthesis for the legislative user
Authors: Chelimsky Eleanor , Morra Linda G.
Published: January 2005

Evaluation synthesis is a form of meta‐analysis developed by the U.S. General Accounting Office as a strategy for increasing congressional use of evaluative findings.
Economic directions for program evaluation
Authors: Catterall James S.
Published: January 2005

What do the preceding chapters suggest about the role of economic analysis in program evaluation, and where might efforts to improve these tools be concentrated?
Accounts receivable treatments study
Authors: Perng Shien S.
Published: January 2005

Six methods were tested to determine their effectiveness in collecting the balance due from individual delinquent accounts. Based on the results of this study, a selection system was developed to match a particular method with each particular delinquent account.
Negotiated solutions to overcoming impediments in a law‐related experiment
Authors: Goldman Jerry
Published: January 2005

Three arenas for negotiation in design and execution of randomized experiments are discussed for a major field test of pretrial hearings.
The teaching of evaluation in education
Authors: Sanders James R.
Published: January 2005

The diversity and abundance of course materials used to teach educational evaluation reflect its varied roles and demands. A single core course cannot produce evaluation competence.
Conceptual crossroads: Methods and ethics in ethnographic evaluation
Authors: Fetterman David M.
Published: January 2005

Methodological design and implementation are often entangled in a web of ethical considerations.
Managing productivity of health care organizations
Authors: Sherman H. David
Published: January 2005

Improving the efficiency and reducing the cost of health care is a particularly complex task, DEA can be used to identify real hospital inefficiencies and opportunities for cost reduction that more traditional techniques do not reveal.
Data envelopment analysis: Critique and extensions
Authors: Sexton Thomas R. , Silkman Richard H. , Hogan Andrew J.
Published: January 2005

This chapter points out serious shortcomings in DEA's treatment of price efficiency, illustrates the dangers of misspecification errors in DEA, and suggests extentions of the basic DEA formulation that address these shortcomings.
Multiple dependent variables in program evaluation
Authors: Hunter John E.
Published: January 2005

Many purposes can be served by using multiple dependent variables in a study, and the application of path analysis to multiple measures can increase both conceptual and statistical power.
Federal evaluation in an executive environment: Two programmatic principles
Authors: Barkdoll Gerald L. , Sporn Douglas L.
Published: January 2005

The impact, speed, and cost‐effectiveness of an evaluation can be increased by building a network of working relationships and by selecting the best method of communicating evaluation results.
The use of profiles and models in evaluating program environments
Authors: Conrad Kendon J. , Hanrahan Patricia , Hughes Susan L.
Published: January 2005

Profiling and modeling are ways of describing program environments that can improve the tailoring of policies, resources, and services to the most appropriate participants.
Increasing client involvement in evaluation: A team approach
Authors: Wye Christopher G.
Published: January 2005

This case study describes an effective team effort and offers perspectives on the short‐ and long‐term impacts of the approach.
Guttman scaling for development project evaluation and prescription
Authors: Gore Peter , Naranjo Eduardo
Published: January 2005

In an era of decreasing resources and expanding populations, Guttman scaling helps to ensure that development projects are appropriately located and have the greatest possible impact for a given investment.
Evaluation of health promotion media campaigns
Authors: McKillip Jack
Published: January 2005

Difficulties in identifying no‐treatment baselines for comparison with media effects in health promotion programming are caused by the self‐selective nature of media exposure and a reliance on nonequivalent comparison groups. Two potential evaluation design solutions that avoid these problems are presented and discussed.
Evaluation as critical inquiry: School improvement as a case in point
Authors: Sirotnik Kenneth A. , Oakes Jeannie
Published: January 2005

Values, beliefs, and human interests are embedded in evaluation theory and practice. For organizations such as public schools to engage seriously in improvement and change efforts, this normative content must be explicitly addressed. Critical inquiry provides an evaluative paradigm for doing so.
Evaluating and ensuring high‐tech product quality
Authors: Halpern Edward S.
Published: January 2005

A summative product evaluation is not as useful to a high‐tech organization as is a formative evaluation that focuses on front‐end process methodology and continual testing of the evolving product.
Unexpected lessons: Evaluation of job‐training programs for single mothers
Authors: Cottingham Phoebe H.
Published: January 2005

Rigorous evaluation of a few, rather than many, sites can uncover new program strategies.
How organizations differ: Implications for multisite program evaluation
Authors: Guastello Stephen J. , Guastello Denise D.
Published: January 2005

Groups and organizations, like individuals, have “personalities” that can affect program outcomes.
From respondent and informant to consultant and participant: The evolution of a state agency policy evaluation
Authors: Baizerman Michael , Compton Donald
Published: January 2005

Program evaluation can invite dialogue with the people affected and, in so doing, become a chorale of many voices.
Client‐level outcomes of mental health services for children and adolescents
Authors: Heflinger Craig Anne
Published: January 2005

A client‐level focus is needed when examining the effectiveness of mental health interventions. Three broad domains of outcomes (psychopathology, social competence, and satisfaction) are explored from the vantage points of client, professional, and societal stakeholders.
The analytical work of the Office of Technology Assessment
Authors: Hildes Elizabeth A.
Published: January 2005

The Office of Technology Assessment had a controversial beginning amid charges of politicization and poor‐quality work. But during the 1980s a better assessment process, including broader participation by client groups and greater oversight by technical experts, led to radically improved studies.
Audits and case studies: Contrasting styles of investigation
Authors: Schwandt Thomas A.
Published: January 2005

Salient features of a modified evaluation audit and a case study evaluation are presented to illustrate two different approaches to investigation.
Implications for popular evaluation approaches
Authors: Scriven Michael
Published: January 2005

The set of theses listed here addresses the consequences of the transdisciplinary view for popular views of program evaluation.
Intermediate evaluation design issues
Authors: Scriven Michael
Published: January 2005

This chapter begins to refine the concepts and processes involved in evaluation design. For example, it moves from generic evaluation designs to specific designs depending on whether a ranking, a grading, or an apportioning is required. And it gives proper place to synthesis, which is so often done impressionistically or not done at all.
Case studies of Chicago schools under reform
Authors: Hess, G. Alfred , Flinspach Susan Leigh , Ryan Susan P.
Published: January 2005

The effort to restructure the Chicago public schools is examined as it is played out in fourteen representative schools. While systemwide structural change is impressive and resources have been redirected to the school level, the authors argue that schools must now focus on pragmatic planning for instructional change.
Improving the quality of randomized field experiments: Tricks of the trade
Authors: Dennis Michael L. , Boruch Robert F.
Published: January 2005

Most evaluators of social programs have little training or experience in designing or conducting field experiments. The goal of this chapter is to describe strategies that could be used to improve the design, implementation, and analysis of randomized field experiments.
The gradual extinction of evaluation within a government agency
Authors: Mowbray Carol T.
Published: January 2005

Politicization and a fiscal control emphasis in a state government agency paralyzed the operation of a previously functional and well‐staffed evaluation division, as described in this case study.
Evaluation misuse from a user's perspective
Authors: Stevens Carla J.
Published: January 2005

A decision maker who uses program evaluations in an educational setting identifies four types of evaluation misuse and provides two case studies in which evaluators misused their positions and the evaluations by not modifying research questions that were determined to be inappropriate.
Program evaluation in science education: The model perspective
Authors: Altschuld James W. , Kumar David
Published: January 2005

This chapter describes a comprehensive model for the evaluation of science education programs that was developed from existing models. Observations are also provided regarding the role of evaluation models in the reform of science education.
Ion channel expression by white matter glia: I. Type 2 astrocytes and oligodendrocytes
Authors: Barres Barbara A. , Chun Linda L. Y. , Corey David P.
Published: January 2005

White matter is a compact structure consisting primarily of neuronal axons and glial cells. As in other parts of the nervous system, the function of glial cells in white matter is poorly understood. We have explored the electrophysiological properties of two types of glial cells found predominantly in white matter: type 2 astrocytes and oligodendrocytes. Whole‐cells and single‐channel patch‐clamp techniques were used to study these cell types in postnatal rat optic nerve cultures prepared according to the procedures of Raff et al. (Nature, 303:390–390, 1983b). Type 2 astrocytes in culture exhibit a “neuronal” channel phenotype, expressing at least six distinct ion channel types. With whole‐cell recording we observed three inward currents: a voltage‐sensitive sodium current qualitatively similar to that found in neurons and both transient and sustained calcium currents. In addition, type 2 astrocytes had two components of outward current: a delayed potassium current which activated at 0 mV and an inactivating calcium‐dependent potassium current which activated at −30 mV. Type 2 astrocytes in culture could be induced to fire single regenerative potentials in response to injections of depolarizing current. Single‐channel recording demonstrated the presence of an outwardly rectifying chloride channel in both type 2 astrocytes and oligodendrocytes, but this channel could only be observed in excised patches. Oligodendrocytes expressed only one other current: an inwardly rectifying potassium current that is mediated by 30‐ and 120‐pS channels. Because these channels preferentially conduct potassium from outside to inside the cell, and because they are open at the resting potential of the cell, they would be appropriate for removing potassium from the extracellular space; thus it is proposed that oligodendrocytes, besides myelinating axons, play an important role in potassium regulation in white matter. The conductances present in oligodendrocytes suggest a “modulated Boyle and Conway mechanism” of potassium accumulation.
Increased glial fibrillary acidic protein synthesis in astrocytes during retrograde reaction of the rat facial nucleus
Authors: Tetzlaff W. , Graeber M. B. , Bisby M. A. , Kreutzberg G. W.
Published: January 2005

Glial fibrillary acidic protein (GFAP) increases in astrocytes following axotomy of facial motoneurons. In the present study we quantified GFAP synthesis both in regenerating facial nuclei after nerve crush and in nonregenerating facial nuclei after nerve resection. An increase in GFAP synthesis during regeneration occurs as early as 24 h after the axotomy. Thus, the increase in the astrocytic GFAP synthesis seems to be the earliest glial response to retrograde changes in facial motoneurons.
Expression of the 2′,3′‐cyclic nucleotide 3′‐phosphohydrolase gene and immunoreactive protein in oligodendrocytes as revealed by in situ hybridization and immunofluorescence
Authors: Vogel U. S. , Reynolds R. , Thompson R. J. , Wilkin G. P.
Published: January 2005

In order to investigate the role of the myelin‐associated enzyme 2′ 3′‐cyclic nucleotide 3′‐phosphohydrolase in the development of the myelin sheath, as well as genetic factors involving dysmyelinating disorders, we have recently isolated and sequenced cDNAs corresponding to the CNPase protein. In this study we have used 32P‐labeled bovine CNPase cDNA probes to localize the messenger RNA coding for this enzyme in mouse cerebral and cerebellar cryostat sections and have compared our data with the distribution of the CNPase protein as revealed by immunofluorescence. Specific labeling was localized to the white matter fiber tracts and, in many areas, to individual oligodendrocyte cell bodies. The corpus callosum and the white matter of the cerebellum were heavily labeled. Distribution of the CNPase protein, as detected by immunohistochemical studies, was parallel to that of the CNPase mRNA as detected by in situ hybridization histochemistry, with oligodendrocyte cell bodies and their processes intensely labeled. This study provides strong evidence that the CNPase gene is expressed in the myelin‐producing cells of the central nervous system and that CNPase is synthesized by and stored within oligodendrocytes.
Ultrastructural study of phagocytic activities of young astrocytes in injured neonatal rat brain following intracerebral injection of colloidal carbon
Authors: Al‐Ali Saad Y. , Al‐Zuhair Ali G. H. , Dawod Bassam
Published: January 2005

The cellular reaction to injury in the mature central nervous system (CNS) has been extensively studied in both man and animals, while a detailed study of the reaction of the immature CNS to injury is lacking in the literature. This study was undertaken to elucidate the response of young astrocytes following injection injury to developing brain. Colloidal carbon was applied because it is a suitable markers for phagocytosis, it is nontoxic, and it is readily identifiable by light and electron microscopy. The cerebral cortex of the neonatal rat was injected with 0.1 μl of colloidal carbon solution. The animals were allowed to survive from 1 hour to 30 days postoperation. The brains were fixed by vascular perfusion and processed for light and electron microscopy. Carbon particles were ingested in membrane‐bound vacuoles and sequestered in lysosomes of young astrocytes. Astrocytes, loaded with carbon particles, were identified after 4 days, and were seen in abundance between 10 to 21 days postoperation. Carbon‐laden astrocytes were seen in the immediate vicinity of the site of the injection; in the surrounding, apparently normal, neuropil; and in the perivascular regions. This study demonstrates the ability of young astrocytes to engulf foreign particles injected into the developing brain. The presence of carbon particles in astrocytes located further away from the site of injection is discussed.
Relations between slow extracellular potential changes, glial potassium buffering, and electrolyte and cellular volume changes during neuronal hyperactivity in cat brain
Authors: Dietzel I. , Heinemann U. , Lux H.D.
Published: January 2005

The aim of this investigation is to estimate the contribution of spatial glial K+ buffer currents to extracellular K+ homeostasis during enhanced neuronal activity. Neuronal hyperactivity was induced by electrical stimulation of the cortical surface or the ventrobasal thalamic nuclei of cats (5–50 Hz, 0.1–0.2 ms, two to three times threshold stimulation intensity, 5–20 s). The accompanying slow field potential changes were recorded simultaneously across the grey matter with vertical assemblies of eight micropipettes glued 300 μm apart. Using the Poisson equation, the amplitudes of the underlying current sources and sinks were calculated. The current source densities depended on the depth of recording, frequency, strength, and duration of the stimulation. Current sinks, corresponding to a removal of 0.1–0.5 mmoles of monovalent cations per liter of brain tissue and second from the extracellular space, were observed in middle cortical layers, whereas sources appeared at superficial and deeper sites. These sinks and sources might represent K+ moved across glial membranes by spatial buffer currents. The consequences of glial buffer currents of this magnitude were investigated with model calculations. It turned out that measurements of electrolyte and volume changes of the extracellular space (Dietzel et al. Exp. Brain Res. 40:432–439, 1980; Exp. Brain Res. 46:73–84, 1982) could only partially be explained by spatial buffer currents of this magnitude. Comparison of the calculated values with intracellular measurements in neurons and glial cells (Coles et al. Ann. N.Y. Acad. Sci. 481:303–317, 1986; Ballanyi et al. J. Physiol. 382:159–174, 1987) suggests that spatial buffering combines with an approximately equimolar KCl transport and, depending on the preparation, also K+/Na+‐exchange across glial membranes.
Vimentin: Changes in distribution during brain development
Authors: Hutchins James B. , Casagrande Vivien A.
Published: January 2005

This paper examines both the anatomical changes in the distribution of vimentin intermediate filament protein and the biochemical changes in vimentin and its degradative enzyme during postnatal brain development in the tree shrew (Tupaia belangeri).

A pattern of multiple immunoreactive bands at birth (postnatal day 0, or P0) was revealed in nitrocellulose blots of polyacrylamide gels (“Western blots”). These multiple bands gradually disappear during development, and in the adult a single band at the published molecular weight for vimentin (57 kD) is seen. This pattern of bands probably reflects shifts in the activity of a calcium‐activated vimentin protease.

The changes in the anatomical distribution of vimentin‐immunoreactive (vimentin+) cells and their fine processes parallel the biochemical shifts seen in immunoblots. We have examined the neocortex, lateral geniculate nucleus (LGN), and hippocampus in detail.

During the first postnatal week, vimentin+ glia, especially radial glia, are prominent in both neocortex and hippocampus. In contrast, only a few vimentin+ radial glia remain in the thalamus at this age. Vimentin+ glia appear to coincide with bundles of axons and often seem to outline subdivisions of thalamic nuclei. Additionally, cellular layers of the lateral geniculate nucleus (LGN) appear to stain with antibodies to vimentin several days before the characteristic neuronal cell layers appear in this area.

During the second postnatal week, vimentin+ cells appear in “patches” throughout the cortex. Some subdivisions of the thalamus and hippocampus (as defined by cytoarchitectonic differences in the adult) are distinct when the tissue is stained with an antibody to vimentin, even though a conventional Nissl stain at this age shows no apparent delineation in these same regions. Finally, in the adult, only a few vimentin+ cells remain, primarily in the white matter.

Taken together, these results suggest that the remodeling of vimentin+ intermediate filaments in immature glial cells (including radial glia) is paralleled by the action of the enzyme which breaks down these filaments. The apparent activity of this enzyme is high early in development as radial and other glia are rapidly dividing and undergoing morphological changes, with a decrease in activity in the juvenile and adult brain, as immature glial cells are supplanted by mature forms.
Glial processes, identified through their glial‐specific 130 kD surface glycoprotein, are juxtaposed to sites of neurogenesis in the leech germinal plate
Authors: Cole Robert N. , Morell Robert J. , Zipser Birgit
Published: January 2005

Glial processes, bearing a unique 130 kD surface protein, are located at key sites of morphogenic movement and neuronal differentiation in the leech germinal plate. A midline glial fascicle resides at the primary axis of embryonic symmetry, alongside which teloblasts move as they generate their bandlets of stem cells. The n‐bandlets straddle the midline glia and are known to produce most of the central neuroblasts. The midline glia then defasciculates as neuroblasts begin to aggregate into neuromers. The defasciculated processes expand into these neuromeres, molding the future central neuropile. Neuroblasts will initiate primary axons toward the midline glia. As the neuromeres mature, midline glial process thin out to demarcate the orientation of the future connectives, which are the major longitudinal axon tracts along the midline. Next, segmental but still primordial glia appear in the neuromeres. Initially, they also project longitudinally, then transversely, demarcating the other two major axonal pathways–the central commissures and peripheral roots. Finally, macroglial processes proliferate as massive axon growth invades the central and peripheral nervous system. Thus, glial processes with different developmental histories accompany different aspects of leech neurogenesis. In other systems, glia have been shown to promote the differentiation and the guidance of neurons. It remains to be seen whether the glial‐specific 130 kD protein is a receptor mediating these typical glial functions in the leech germinal plate.
Caprine β‐mannosidosis: Development of glial and myelin abnormalities in optic nerve and corpus callosum
Authors: Lovell Kathryn L.
Published: January 2005

In caprine β‐mannosidosis, an inherited dysmyelinating disorder, the myelin deficit shows substantial variation throughout the nervous system. In this study morphometric analysis of optic nerve and corpus callosum sections at selected developmental stages was conducted in order to investigate development and persistence of myelin sheaths, the population of axons ensheathed, and the extent of myelin deficits and glial cell abnormalities. The results show that the myelin deficit is severe at very early stages of development and persists to about the same extent into postnatal life. The corpus callosum, much more severely involved than the optic nerve, contains a substantially smaller percentage of myelinated axons when compared to control. In both regions, larger axons are preferentially myelinated. In the corpus callosum before myelination begins, many glial cells appear abnormal, suggesting an early cellular defect. In the postnatal, myelin‐deficient corpus callosum, there is a substantial decrease in glial cell density as compared to control, with abnormal appearance of many of the remaining cell profiles. These results define developmental characteristics of the dysmyelination in caprine β‐mannosidosis and document both the early appearance and the persistence of glial cell body and myelin abnormalities.
Serum influences the differentiation of membrane structure in cultured astrocytes
Authors: Landis Dennis M. D. , Weinstein Lori A. , Skordeles Christine J.
Published: January 2005

The membranes of mammalian astrocytic processes apposed to blood vessels or forming the surface of the brain contain high concentrations of a characteristic intramembrane particle aggregate, termed “assemblies.” In order to identify developmental processes which contribute to this remarkable regional specialization of membrane structure, we have devised culture conditions which support the differentiation of assemblies in secondary cultures of astrocytes derived from neonatal rat forebrain. We report here that different lots of fetal calf serum vary dramatically in their capacity to support the differentiation of assemblies. Fetal calf serum thus appears to exert two distinct influences on astrocyte development: it promotes the differentiation of type 2 astrocytes from bipotential precursor cells, as shown by others, and it influences the density of assemblies in type 1, flat, GFAP‐immunoreactive astrocytes in our secondary cultures. Horse serum and defined media also support the appearance of assemblies in flat, GFAP‐immunoreactive astrocytes. The separate effects of serum supplementation upon cell lineage and membrane differentiation have to be carefully considered in studies designed to examine factors influencing astrocytic development in vitro.
Developing forebrain astrocytes are sensitive to thyroid hormone
Authors: Gould Elizabeth , Frankfurt Maya , Westlind‐Danielsson Anita , McEwen Bruce S.
Published: January 2005

Previous studies have shown that developing neurons of the basal forebrain and hippocampus are sensitive to thyroid hormone (Gould and Butcher: J. Neurosci., 9:3347–3358, 1989; Rami et al: Neuroscience, 19:1217–1226, 1986). In order to determine whether or not thyroid hormone influences the development of astrocytes in brain regions where neurons are affected, we performed vimentin and glial fibrillary acidic protein (GFAP) immunocytochemical and single‐section Golgi‐impregnation analyses on the basal forebrain and hippocampus of control and neonatally thyroid hormone treated rats. For purposes of comparison, glial cells of the pontomesencephalotegmental (PMT) region, a region where developing neurons are not morphologically affected by thyroid hormone imbalances (Gould and Butcher, op. cit.), were also examined. Neonatal thyroid hormone treatment resulted in a premature disappearance of vimentin‐immunoreactive radial glia in the basal forebrain and hippocampus. In addition, a premature appearance of GFAP‐immunoreactive astrocytes with mature morphological characteristics was observed in the basal forebrain and hippocampus of thyroid hormone treated animals. Quantitative analyses revealed significant increases in the density of GFAP‐immunostained astrocytes and in the cross‐sectional cell body area and the number of primary processes in Golgi‐impregnated astrocytes of the basal forebrain and hippocampus of animals treated neonatally with thyroid hormone. In contrast, no changes in any of these parameters were observed in glial cells of the PMT region with neonatal thyroid hormone treatment.
Morphological changes of astroglia in the cerebellar cortex of developing mice after neonatal administration of cytosine arabinoside
Authors: Ono Katsuhiko , Mizukawa Kiminao , Yanagihara Mamoru , Tokunaga Akira
Published: January 2005

Neonatal administration of cytosine arabinoside (Ara‐C) induced marked hypoplasia of the mouse cerebellum. In 17–20‐day‐old mice with neonatal Ara‐C injections, the external granular layer was still preserved as an irregular cell laminae in the superficial part of the cerebellum, in contrast to its complete disappearance in normal animals at these stages. Immunohistochemical examination using anti‐glial fibrillary acidic protein and monoclonal antibody‐1D11 (Ono et al: Dev. Brain Res., 50:154–159, 1989) demonstrated malformation of a palisade‐like arrangement of labeled glial fibers in the superficial part of the Ara‐C treated mouse cerebellum. Furthermore, the immunoreactive astroglia were observed just beneath the pial membrane and their processes were oriented to the deeper part of the molecular layer.
Glial influences on axonal growth in the primary olfactory system
Authors: Doucette R.
Published: January 2005

Neurogenesis in the olfactory epithelium continues throughout the entire life of mammals, and it is the axons of these newly formed olfactory receptor neurons that grow into the target tissue after the first cranial nerve is injured, not the regenerating axons of mature cells. These axons are able to enter and grow within the CNS of adult animals, unlike regenerating axons in injured dorsal roots, the majority of which are prevented from penetrating very far into the spinal cord. One reason why the olfactory axons are so successful in entering the CNS may be due, at least partially, to the fact that they are ensheathed by a type of glial cell (the ensheathing cell) that expresses phenotypic features of both astrocyte and Schwann cells. The presence of both L1/Ng‐CAM and N‐CAM in the plasma membranes of both ensheathing cells and immature olfactory receptor neurons would enable the olfactory axons to use the glial cell surfaces as a substratum on which to grow. It is probably also true that ensheathing cells synthesize and secrete laminin, thus providing an additional adhesive substrate for the olfactory axons, as well as glia‐derived nexin and nerve growth factor, both of which are neuritepromoting agents.
Effect of exogenous fatty acids on lipid synthesis, marker‐enzymes, and development of glial cells maintained in serum‐free culture
Authors: Sykes Jane E. C. , Lopes‐Cardozo Matthijs
Published: January 2005

Glial cells were isolated from the cerebra of 7‐day‐old rats and maintained in culture in a chemically defined medium that favours the development of oligodendrocytes. Acetate, butyrate, or albumin‐bound hexanoate, octanoate, decanoate, laurate, myristate, palmitate, oleate, linoleate, or arachidonate was added to the culture medium. The incorporation of [3H]acetate into fatty acids and cholesterol and [35S]sulphate into sulphatide, and the activities of the oligodendrocyte marker enzymes 2′,3′‐cyclic‐nucleotide 3′‐phosphodiesterase and glycerol 3‐phosphate dehydrogenase were measured. The composition of the glial cell population (the number of astrocytes and oligodendrocytes) in these cultures was studied by immunocytochemistry. Results show that 1) long‐chain fatty acids depress the synthesis of fatty acids, cholesterol, and sulphatide; and 2) the presence of long‐chain, in contrast to short‐chain, fatty acids in the culture medium lowers the activities of 2′,3′‐cyclic‐nucleotide 3′‐phosphodiesterase and glycerol 3‐phosphate dehydrogenase and decreases the number of oligodendrocytes. Our results suggest that long‐chain fatty acids exert a negative influence on the development of oligodendrocytes in the culture system used.
Reactive astrogliosis after basic fibroblast growth factor (bFGF) injection in injured neonatal rat brain
Authors: Eclancher Francoise , Perraud Frederic , Faltin Jan , Labourdette Gerard , Sensenbrenner Monique
Published: January 2005

Reactive gliosis was revealed by immunocytochemistry using antibodies against the glial fibrillary acidic protein (GFAP) after a stab or an electrolytic lesion administered to the cerebral cortex, corpus callosum, striatum, or hippocampus of a 6‐day‐old rat. The intensity of the gliosis was about the same in the various structures injured and did not change with the delay of 3, 7, or 20 days between the injury and the sacrifice of the animals. When basic fibroblast growth factor (bFGF) was injected in the lesion locus just after the lesion was performed, it resulted (as soon as 3 days after injury) in a strong astrogliosis that was enhanced after a delay of 7 days, the astrocytes in the lesion area exhibiting enlarged cell processes and intense GFAP‐positive immunoreactivity. After a delay of 20 days, the astrocytes were not dispersed any more but packed in three or four layers along the borders of the lesion, thus reducing its extension. This suggests a possible role for bFGF in promoting scar formation following brain injury.