bluuebunny/crossref_metadata_2025 huggingface dataset:
Topological correlation between the cell‐recognition protein, R‐cognin and α‐bungarotoxin receptor in retinal plasma membrane
Authors: Hausman R.E. , Christie T. , Gliniak B.C. , Rosenkrans W.A.
Published: April 2003

The amount of the neural retina cell recognition protein, R‐cognin, in the plasma membrane of chick embryo neural retina cells declined 43% between 10 and 17 days of embryonic development. Over this period there was a 27% increase in the plasma membrane content of the α‐bungarotoxin receptor. Plasma membranes of both these ages were sonicated into vesicles and these vesicles partitioned on α‐bungarotoxin agarose beads into those which contained detectable α‐bungarotoxin receptor and those which did not. At 10 days, approximately 6% of the plasma membrane vesicles contained receptor. At 17 days, <2% did. At 10 days, 60% of the R‐cognin was found in the α‐bungarotoxin receptor‐containing vesicles, at 17 days 86%. At 17 days, 6% of the retina membrane with a high concentration of both α‐bungarotoxin receptor and R‐cognin was of a density indicative of it being of synaptic origin. These results suggested that R‐cognin and α‐bungarotoxin receptor occurred close together in the plasma membrane of retina cells. However, the lack of competition between R‐cognin gamma globulin and specific α‐bungarotoxin binding indicated that the α‐bungarotoxin receptor and R‐cognin were not the same protein. Thus, R‐cognin and the α‐bungarotoxin receptor appear to be separate proteins which occur in close proximity on the retina plasma membrane.
Postnatal development of transmitter systems: Sexual differentiation of the gabaergic system and effects of muscimol
Authors: Flügge G. , Wuttke W. , Fuchs E.
Published: April 2003

The development and sex differences of the central nervous GABAergic system were examined by measuring GABA (γ‐aminobutyric acid) in discrete brain nuclei of the hypothalamus, as well as the nigrostriatal and the limbic systems of male and female rats on the day of birth and on days 5, 10, and 15. The highest concentrations were found in the hypothalamic and nigrostriatal nuclei; the lowest in the limbic system. Sex differences were observed only on day 10 in the medial preoptic area, with GABA being higher in males than in females; and also in the substantia nigra, where female GABA levels were higher than male. These results suggested an involvement of GABA in the sexual differentiation of the brain. As a control, concentrations of the GABA precursor glutamate were determined. No sex differences in glutamate concentrations were found in any brain region during the first 15 days postnatally.

Since a GABA mimetic substance applied during the critical period of brain differentiation could disturb the development of the GABAergic system, the consequences of a perinatal treatment with the GABA agonist muscimol were investigated. Significant reduction of GABA concentrations by muscimol were observed in the hypothalamic and nigrostriatal systems at specific times postnatally. On day 5, GABA concentrations were diminished only in the medial preoptic area, then on day 10, in the anterior hypothalamus and the substantia nigra and still later, on day 15, in the caudato putamen. In contrast, the effects of muscimol on glutamate concentrations could be observed over a longer postnatal period. Glutamate was already diminished on day 5 in 7 areas of the hypothalamic, nigrostriatal and limbic systems.
Corticosterone therapy during gestation: Effects on the development of rat cerebellum
Authors: Velazquez P. N. , Romano M. C.
Published: April 2003

Corticosterone (1 μg/g) was administered to the pregnant rat mother at 17, 18 and 19 days of gestation. The pups were killed at birth or at 6 or 12 days of age and the morphological and biochemical development of the brain, with special emphasis in the cerebellum was studied. The brain and cerebellar weight was slightly diminished in the corticosterone treated animals. Corticosterone produced changes in the pattern of development of the cerebellar layers, causing an accelerated decrement of the external granular layer at 12 days of life. The total protein content of the cerebellum was increased in the hormone treated pups at birth, 6 and 12 postnatal days. Newborn corticosterone treated animals showed a decreased DNA content, but this phenomenon was completely reversed at 12 days. It was concluded that corticosterone given to the pregnant mother influences the time pattern of the development of the brain and the cerebellum.
Immunolocalization of dipeptidyl aminopeptidase (DAP IV) in the developing human brain
Authors: Bernstein Hans‐Gert , Schön Eckhard , Ansorge Siegfried , Röse Ingeborg , Dorn Alfred
Published: April 2003

By means of immunohistochemical techniques we have investigated the presence of dipeptidyl aminopeptidase IV immunoreactivity in brain material derived from human fetuses, new‐borns and aged persons. It was revealed that the enzyme protein is abundantly present in the immature human CNS. On the contrary the adult human brain contains much less dipeptidyl aminopeptidase immunoreactivity. It is speculated that the enzyme might play an important role in neuronal proliferation and/or differentiation especially with regard to its possible action on certain neuronotrophic peptides (IGF II, growth hormone).
Astroglial plasticity in hemizygous and heterozygous jimpy mice
Authors: Best Todd T. , Skoff Robert P. , Bartlett William P.
Published: April 2003

Gliosis is a common phenomenon which occurs in many human diseases and in experimentally altered nervous tissue. The factors activating astrocytes to respond are still unclear but recent evidence suggests that diverse substances can provoke a gliotic response. This paper describes the nature of the gliosis in the myelin deficient jimpy and relates these findings to other recent studies of experimentally induced demyelination in which gliosis is a prominent feature of the disorder.

In jimpy males, an astroglial hypertrophy which consists of an increase in the number of cell processes can be demonstrated by both electron microscopy and immunocytochemistry using antibodies to glial fibrillary acidic protein. Increased glial fibrillary acidic protein staining in the white matter of jimpy males correlates with the normal time of myelination in different tracts. The immunostaining is not, however, restricted to white matter. Increased staining can be demonstrated in spinal cord grey matter when hardly any myelinated fibers are present, it is especially prominent around blood vessels of both white and grey matter, and is found in the corpus callosum and in the underlying subventricular zone shortly before or at the time myelination begins in this tract. These observations suggest that the hypertrophy is not simply a response by the astrocyte to the absence of myelin sheaths.

While an astroglial hypertrophy is dramatic in jimpy males, quantitative counts of astrocytes and electron microscopic autoradiograms do not reveal an increase in the total number of this cell type. These findings suggest that hyperplasia and hypertrophy of astrocytes may be under separate regulatory control with different factors involved in each phenomenon.

In the female carriers of the jimpy gene, myelination is temporarily delayed during postnatal development but after several months, the amount of myelin, whether measured morphometrically or biochemically, reaches normal levels. In the white matter of the young female carrier, staining for glial fibrillary acidic protein is increased in terms of the number of processes and the total volume of neuropil but a normal pattern of staining is observed within a year. These and other observations suggest that the glial hypertrophy in the young mosaic is temporary and that regression and reorganization of glial processes takes place as myelination proceeds.
Neuron‐specific enolase during the development of the organ of corti
Authors: Whitlon Donna S. , Sobkowicz Hanna M.
Published: April 2003

NSE immunoreactivity has been studied in the organ of Corti of the developing mouse from birth to 21 days. NSE immunohistochemical stain is observed in spiral ganglion cells, in nerve fibers and in nerve endings of inner and outer hair cells, and in both populations of sensory cells. Spiral ganglion cells in lower and central parts of the ganglion stain for NSE at birth, but all nerve cells are stained by day 4. Radial and spiral fibers and the endings on inner hair cells stain at birth, but the nerve endings on outer hair cells develop NSE between days 3 and 6. The inner and outer hair cells are NSE‐positive at day 2 but the NSE immunoreactivity in the outer hair cells decreases at the end of the second week until the cells become negative. The NSE stain in the neuronal pathways of the inner and outer hair cell regions increases for about 19 days, showing a predominant accumulation in neuronal endings. The data suggest that the development of NSE expression in the organ of Corti reflects the nascence and maturation of the synaptic contacts.

Spiral neurons, their fibers and endings as well as inner and outer hair cells express NSE in the isolated organ of Corti in culture. Variability of stain among the different cell populations indicates a role of local factors in the regulation of NSE expression.
Ontogenetic and pharmacological dissociation of various components of locomotor activity and habituation in the rat
Authors: Laviola Giovanni , Renna Giuseppe , Bignami Giorgio , Cuomo Vincenzo
Published: April 2003

Sprague‐Dawley‐derived male rats were used to investigate locomotor activity and habituation in an open field as a joint function of developmental age (2–6 weeks), pattern of test exposure (single 30‐min test vs three 5‐min tests at 24‐hr intervals), and treatment conditions (i.p. saline, d‐amphetamine sulfate 1mg/kg, or scopolamine hydrocloride 0.5 mg/kg). No‐drug animals showed low activity levels in both tests at the end of the second week, intermediate response rates at the end of the third week, and a typical adult‐like pattern at later ages (high initial activity followed by marked withinsession or between‐session habituation). Amphetamine effects varied considerably depending jointly on age and type of test. At the end of the second week, the drug hyperactivity was much more marked in successive brief tests than in the single extended test. One week later, the response increase was rather uniform in both tests. At the end of the fourth week, the sensitivity profile was reversed, consisting of a large drug effect in the extended test but not in successive brief tests. Scopolamine was still without effects at this age, while a typical hyperactivity was produced by the drug in 6‐week‐old animals. These data show that, at least in the rat strain used, the functional maturation of muscarinic regulatory systems is not a necessary condition either for the appearance of an adult‐like response pattern, or for the occurrence of the age‐ and test‐related changes of the amphetamine profile. Overall, the data point (i) to the existence of some mechanism serving the suppression of locomotion during the initial phase of exposure to a novel environment at 2 weeks and (ii) to separate mechanisms for within‐session and between‐session habituation developing at later stages.
Isolated hippocampal neurons in cryopreserved long‐term cultures: Development of neuroarchitecture and sensitivity to NMDA
Authors: Mattson Mark P. , Kater S. B.
Published: April 2003

Isolated neurons in long‐term culture provide a unique opportunity to address important problems in neuronal development. In the present study we established conditions for cryopreservation and long‐term primary culture of isolated embryonic hippocampal neurons. This culture system was then used for initial characterizations of the development of neuroarchitecture and neurotransmitter response systems. Cryoprotection with 8% dimethylsulfoxide, slow freezing, and rapid thawing provided high‐yield cultures which appeared normal in terms of cell types, mitotic ability, axonal and dendritic outgrowth, and sensitivity to glutamate neurotoxicity. A reduced medium volume and moderate elevation in extracellular K+ to 20 mM promoted survival of isolated neurons through 3 weeks of culture. The outgrowth of axons and dendrites in pyramidal‐like neurons was found to differ over a 3‐week culture period such that axons continued to grow at a relatively constant rate while dendritic outgrowth slowed during the second week and ceased by the end of week 3. Developmental changes were also observed in the sensitivity of pyramidal neurons to glutamate neurotoxicity; functional kainate/ quisqualate receptors were present during the first week of culture, while responses to N‐methyl‐d‐aspartic acid (NMDA) did not appear until the second week. The technologies for cryopreservation and long‐term culture of isolated hippocampal neurons reported here provide a useful system in which to address a variety of problems in developmental neuroscience.
Expression of the three opioid receptor subtypes μ, δ and κ in guinea pig and rat brain cell cultures andin vivo
Authors: Barg Jacob , Levy Rivka , Simantov Rabi
Published: April 2003

Expression of the three opioid receptor subtypes mu, delta and kappa in aggregating cell cultures prepared from embryonic guinea pig or rat brains was compared with thein vivo expression of the receptors in the brain of developing and adult animals of the same species. At the day of culturing, one third of the receptors in the brain of guinea pig embryos were of the kappa type. In culture, however, the aggregating brain cells acquired within 14 days a high percentage (75%) of kappa receptors. As only 28% of the receptors in the adult guinea pig brain are of this subtype, an attempt was made to further analyse the specificity of this developmental process.

In guinea pig, the 2‐fold increase in kappa receptors in culture was accompanied with a decline in both the percentage and the density (per protein) of mu and delta subtypes. In contrast, a marked increase in delta receptors was observed in rat whole brain, forebrain or hindbrain cultures. Thus, the developmental pattern of the three receptor subtypes in rat brain cultures, but not in guinea pig, was similar to thatin vivo. These and additional experiments suggest that at the developmental stage taken to prepare the cultures, neurons expressing opioid receptors were already programmed in the rat but not in guinea pig brain.
Proliferation‐related responses in rat astrocytes to epidermal growth factor
Authors: Huff Kenneth R. , Schreier Wayne , Ibric Luminita
Published: April 2003

The signals which regulate the proliferation of astrocytes have relevance to both normal developmental processes and abnormal states of gliosis or glial tumor formation. We have extended studies of astrocyte proliferation and related responses in primary cultures of rat telencephalic cortical astrocytes as a result of treatment with epidermal growth factor. Epidermal growth factor stimulates the rate of DNA synthesis five fold and maintains the rate of protein synthesis. The stimulation occurs at a dose of 2 ng/ml and is greater in higher density cultures than in lower density cultures, perhaps representing a relative starvation for the growth factor. The astrocyte response is still present even after being cultured 31/2 weeks in serum‐free and non‐growth factor or hormone‐supplemented media. Combined immunofluorescence and thymidine autoradiography disclose that glial fibrillary acidic protein containing cells are the cells synthesizing DNA in response to the growth factor, and combined rhodamine and fluorescein‐linked stains disclose that epidermal growth factor is in the glial fibrillary acidic protein containing cells. Proliferation‐related 2‐deoxyglucose uptake is stimulated at approximately the same dose as DNA synthesis is stimulated, but the time course is relatively slow, maximizing at 48 hr. Ornithine decarboxylase is stimulated in 6 hr indicating more rapid nuclear stimulation by the signal. In conclusion, epidermal growth factor has a clear direct interaction with glial fibrillary acidic protein‐containing cells which is greater in higher density cultures, is still present in long‐quiescent cells, and includes DNA synthesis, cell cycle progression, hexose uptake, and polyamine synthesis.
Postnatal development of two nicotinic cholinergic receptors in seven mouse brain regions
Authors: Fiedler Eric P. , Marks Michael J. , Collins Allan C.
Published: April 2003

The developmental profiles for binding of α‐[125I]bungarotoxin and l‐[3H]nicotine to putative nicotinic cholinergic receptors were determined in seven mouse brain regions. The overall pattern of development of α‐bungarotoxin binding was similar in all of the regions. Neonatal binding values tended to be greater than those observed in adult brain regions. Maximal binding occurred within 10 days of birth and adult binding values were reached by 20 days of age. The patterns of development of nicotine binding in each of the seven brain regions differed according to region. Gross similarities in developmental profiles for nicotine binding were found among the more caudal and among the more rostral regions. In hindbrain and cerebellum, maximal nicotine binding was found at birth (5 days of age in cerebellum); binding declined approximately 4‐fold by 20 days and remained relatively constant thereafter. In midbrain and hypothalamus, a less extensive decrease in nicotine binding occurred from birth to adulthood (midbrain, 25%; hypothalamus, 50%). Nicotine binding in hippocampus and cortex remained unchanged between birth and adulthood. The developmental pattern for nicotine binding in striatum differed from that found in the other brain regions. At 5 days of age, binding was about 65% of adult binding, which was reached at 30 days of age. In most of the brain regions the developmental profile for α‐bungarotoxin binding was different from that of nicotine. This difference was especially notable in striatum, where adult nicotine binding was higher than neonatal nicotine binding, whereas adult α‐bungarotoxin binding was lower than neonatal α‐bungarotoxin binding.
Synapse formation on trochlear motor neurons under conditions of increased and decreased cell death during development
Authors: Sohal G.S. , Kumaresan K. , Hirano S. , Ali M.M.
Published: April 2003

There is a normally occurring death of about half of the trochlear motor neurons during development. Early removal of the target muscle results in death of almost all neurons whereas neuromuscular blockade prevents neuron death. The present investigation was undertaken to determine whether the number of central afferent synapses on motor neurons is altered under conditions which either accentuate cell loss or rescue neurons. The sole peripheral target of innervation of the trochlear motor neurons, the superior oblique muscle, was extirpated in duck embryos before the motor axon out‐growth begins. The neuromuscular blockade was achieved by application of paralyzing dosages of alpha bungarotoxin on to the vascularized chorioallantoic membrane. This treatment began prior to the onset of cell death and embryos were treated daily throughout the period of cell death. Brains were processed for electron microscopy and quantitative observations were made on synapses at the onset, during the period of, and at the end of cell death. It was found that there was no significant difference in the number of synapses on neurons following target removal, following neuromuscular blockade, and those developing normally. This observation indicates that the number of central afferent synapses on cell soma is not altered under conditions which either decrease or increase neuron survival. These results suggest that the synapse number per se may not be directly involved in the process of naturally occurring cell death. The results also suggest that the number of synapses on trochlear motor neurons is independent of interactions with the target.
Individual C6 glioma cells migrate in adult rat brain after neural homografting
Authors: Goldberg William J. , Laws Edward R. , Bernstein Jerald J.
Published: April 2003

Cultured C6 glioma cells were prelabeled with the plant lectin Phaseolus vulgaris leucoagglutinin (PHAL) and grafted as a cell suspension (106 cells in 5.0 μl) into freshly made cortical implantation pockets in adult host rats. Animals were killed 1–21 days post‐implantation (DPI). The brains were removed, dehydrated, embedded in paraffin and sectioned at 8 μm. Paraffin sections were processed for light level immunofluorescent double labeling for PHAL, a marker for graft derived cells, and glial fibrillary acidic protein (GFAP), a specific marker for C6 glioma cells and astrocytes. Cells positive for both PHAL and GFAP were graft‐derived C6 cells. By 7 DPI a large mass developed which extended above the surface of the brain and invaded (displacement of host tissue by a cell mass) the host parenchyma. This mass increased in size over the next 14 days. The invading tumor mass contained double labeled cells at all time periods examined. In addition to the invasion process, grafted C6 cells spread through the host parenchyma by migration (movement of single cells). Individual graft‐derived C6 (GFAP/PHAL positive) cells migrated into host cortex surrounding the implantation pocket, corpus callosum ventral to the implantation pocket, ipsilateral internal capsule and bilaterally in the habenula.
Recovery of vestibular function in young guinea pigs after streptomycin treatment. Glutamate decarboxylase activity and nystagmus response assessment
Authors: Meza Graciela , Solano‐Flores Luis P. , Poblano Adrián
Published: April 2003

Fifty‐day streptomycin (STP) treatment in guinea pigs causes specific vestibular hair cell (VHC) types I and II (HCI; HCII) degeneration, depletion of glutamate decarboxylase (GAD) and a gradual disappearance of postrotatory nystagmus response (PRNR), which is a sign of vestibular function alteration. In order to look for a possible spontaneous reversibility and its time course guinea pigs receiving 300 mg/kg STP daily were monitored for PRNR and vestibular GAD loss. Once PRNR was lost, STP was interrupted and the animal was allowed to recover; at the time that PRNR was completely reestablished, vestibular GAD was measured.

PRNR was lost within 22–25 days of STP treatment. Vestibular GAD showed a loss that, with time of treatment, gave two slopes: a fast decrement (45% in 20 days) and a slow one (40% in the remaining 30). Stopping of the STP treatment after 22–25 days and animal recovery resulted in the return of both PRNR and GAD activity 22 days after STP stoppage.

These results suggest two STP‐susceptible GAD‐containing VHC populations, one more sensitive than the other, possibly HCI followed by hair cell II (HCII). As hypothetic HCI loss and PRNR disappearance is simultaneous, the important role of the former for vestibular function could be inferred. Interruption of STP treatment after PRNR loss results in a long range restoration of both GAD activity and vestibular function, and thus recovery of HCI, the first evidence of its occurrence in a mammalian vestibule, could be suggested. The intimate mechanism of this recovery remains to be seen.
Age‐related changes in NMDA‐induced [3H]acetylcholine release from brain slices of senescene‐accelerated mouse
Authors: Zhao Xue‐Hui , Kitamura Yoshihisa , Nomura Yasuyuki
Published: April 2003

From the brain slices of normal mice (ddY strain, subcloned from dd strain in National Institute of Health in Japan), N‐methyl‐d‐aspartic acid (NMDA) at 0.01~1 mM evoked [3H]acetylcholine (ACh) release in a concentration dependent manner. [3H]ACh release evoked by 1 mM NMDA was significantly inhibited by 2‐amino‐5‐phosphonovaleric acid (APV), phencyclidine (PCP) and 5‐methyl‐10,11‐dihydroxy‐5H‐dibenzo[a,d]cyclo‐hepten‐5,10‐imine maleate (MK‐801). The effects of NMDA were not seen in the Ca2+ free medium and were inhibited by physiological concentration (0.83 mM) of Mg2+. NMDA seems to cause ACh release from nerve terminals through the receptorion channel mediated mechanism in the mouse brain. Based upon these results, we determined the activity of a high K+‐ or NMDA‐evoked [3H] ACh release using prone/8 strain of senescence‐accelerated mouse (SAM‐P/8) (a murine model of accelerated aging and memory dysfunction) and SAM‐resistance/1 strain (SAM‐R/1) (normal aging mice as the control) and these release activities were compared between both strains and during aging. [3H]ACh release evoked by 30 mM KCl was significantly lower than that of age‐matched SAM‐R/1 at 9 and 12 months. NMDA evoked the [3H]ACh release at 2, 6, 10 and 14 months in R/1 mice. In SAM‐P/8 mice the activity of NMDA‐evoked release was seen at 2 months, but markedly decreased afterwards. Nonsignificant difference was observed on the uptake of [3H]choline and on the spontaneous release of [3H]ACh between SAM‐P/8 and SAM‐R/1 strains, and during aging. These results suggest: (1) NMDA receptor‐ion channels are involved in the ACh release from nerve terminals in the CNS; (2) the NMDA‐evoked ACh release is decreased after 6 months in SAM‐P/8 mice but not in SAM‐R/1 mice; and (3) the high K+‐evoked ACh release is decreased at an earlier age in SAM‐P/8 than it is in SAM‐R/1. These results suggest that the NMDA‐ and cholinergic‐system in the CNS seems to be deficient in SAM‐P/8 and that this deterioration may be a possible cause for their dysfunction of learning and memory.
Morphological correlates of physiological responses in partially denervated mouse muscle during aging
Authors: Fahim Mohamed A.
Published: April 2003

To evaluate the effect of partial denervation on age changes, morphological and physiological parameters were studied in young versus old extensor digitorum longus (EDL) muscles. The aims of this study were to elucidate synaptic maintenance in general and specifically to assess the adaptability of motor neurons from young and old animals to an enlarged field of innervation. Partial denervation was carried out in two groups of 30–40 g mice, aged within 6 or 24 months, by sectioning of the nerve supplying EDL muscle under methoxyfluorane anaesthesia. Sham operations were carried out on additional animals which served as controls. Five weeks' post‐surgery, the safety factor of synaptic transmission was estimated by dividing the nerve‐evoked twitch tension generated in 1 mM Ca2+ Krebs by that generated in 2.5 mM Ca2+ Krebs. Low Ca2+ Krebs caused a more pronounced decline in twitch tension in young control EDL muscles than old control. After partial denervation, young EDL twitch tensions were not significantly different while old were 20% of those in normal Krebs. Zinc Iodide Osmium (ZIO) stained nerve terminal parameters were significantly increased with aging. After partial denervation, nerve terminal areas were 46 and 39% larger in young and old mice, respectively, compared to their corresponding controls. Present data suggest that motor neurons of old mice are unable to develop and maintain an enlarged field of innervation.
Peripheral nerve regeneration: Role of growth factors and their receptors
Authors: Raivich Gennadij , Kreutzberg Georg W.
Published: April 2003

Growth factors play a central role in the regulation of normal and injury‐induced regenerative cell growth. The purpose of this article is to summarize the available data on the expression of different growth factors and their receptors in the injured peripheral nervous system and to discuss their possible role in promoting peripheral nerve regeneration.
Environmental regulation of brain trophic interactions
Authors: Black Ira B.
Published: April 2003

Emerging evidence indicates that trophic interactions that influence brain development are critical throughout life, mediating processes as diverse as learning, memory and regrowth after injury. This review summarizes recent work suggesting that impulse activity regulates trophic interactions in the brain, allowing the conversion of millisecond‐to‐millisecond signalling into long‐term changes in neural circuit function. For example, depolarizing stimuli regulate trophic factor gene expression, an effect mediated by excitatory transmitters. Responsiveness to trophic factors is also regulated by activity, since depolarization increases the expression of trophic receptor genes. Moreover, different excitatory transmitter receptor subtypes mediate trophic or regressive effects, allowing a neural system to precisely memorialize excitatory or inhibitory experiences. A number of open questions are articulated to define potential future directions.
Schwann cells transplanted into the CNS
Authors: Raisman G. , Lawrence J.M. , Brook G.A.
Published: April 2003

A small volume of purified Schwann cells, cultured from early postnatal rat sciatic nerve, was injected into the hippocampus or fimbria of syngeneic adult hosts. The procedure caused minimal structural disturbance at the transplantation site, with close graft‐host contact and maximal opportunity for integration.

The donor Schwann cells were identified by a combination of light and electron microscopic features (which include characteristic deep and complex infoldings of a well marked nuclear envelope), antigenic profile (especially low affinity nerve growth factor receptor immunoreactivity), uptake of fluorescent latex microspheres and autoradiography of [3H]thymidine‐labelled dividing cells.

The donor Schwann cells adopted a distinctive elongated form, with a central, ovoid nucleus flanked by processes which were up to 300 μm long, and which ranged from swollen segments with a diameter as large as 12 μm down to thread‐like fibres of 1 μm or less with growth cone‐like expansions. Transplanted cells migrated from the graft, particularly along blood vessels, and could permeate all cytoarchitectonic regions of the adjacent host hippocampal neuropil. Donor Schwann cells also migrated along the longitudinal axis of the fimbria, where they were interspersed in parallel with the interfascicular glial rows and axons.

The grafted cells induced a transient but marked host astrocytic hypertrophy, which did not appear to impede the migration of the donor Schwann cells.

The transplanted Schwann cells did not form peripheral myelin (as detected by Po immunoreactivity), and it is not clear whether they survive beyond the period at which we detect them.
Immunohistochemistry of glial reaction after injury in the rat: Double stainings and markers of cell proliferation
Authors: Schiffer D. , Giordana M.T. , Cavalla P. , Vigliani M.C. , Attanasio A.
Published: April 2003

The astrocytic reaction in the rat after brain injury has been studied immunohistochemically for intermediate filaments (GFAP and vimentin), also with double staining procedures, and for markers of proliferation (BrdU and PCNA). GFAP‐positive reactive astrocytes appeared around the lesion, where they were vimentin‐positive and at a distance. BrdU and PCNA showed a high labelling index around the wound at day 2 and scattered positive nuclei were also found at a distance in the ipsilateral side. BrdU‐positive astrocytes represented a minor fraction of GFAP‐ and vimentin‐positive astrocytes. The expression of vimentin persisted at least 15 days after the lesion. Our results could suggest that distant reactive astrocytes originate through hypertrophy while those close to lesion arise by hyperplasia from mature or immature glial cells. The hypothesis is formulated that cells of the periventricular matrix contribute to the post‐traumatic proliferative activity.
Developmental regulation of adult cortical morphology and behavior: An animal model for mental retardation
Authors: Bachman Eric S. , Berger‐Sweeney Joanne , Coyle Joseph T. , Hohmann Christine F.
Published: April 2003

The purpose of this study was to examine the behavioral performance in adult mice which, as neonates, had received lesions to cortically projecting, cholinergic basal forebrain neurons. The nucleus basalis magnocellularis (nBM) provides the primary cholinergic innervation to cerebral cortex. Lesions in the nBM in neonatal mice result in transient cholinergic denervation and persistent abnormalities in cortical morphology and cytoarchitecture. These cortical abnormalities resemble pathologies observed in a number of developmental disabilities in humans, including Down Syndrome. Balb/CByJ mice received lesions to the nBM 12–24 hr after birth; littermates served as controls. Behavioral testing began 8 weeks after the lesion and included assessments of spontaneous motor activity, retention (a passive avoidance task) and cognition (the Morris swim task). Following behavioral testing, a subset of mice was killed for Nissl and acetylcholinesterase (AChE) histology. The cortical morphology in these brains was evaluated and ranked by the experimenter, who was blind to the lesion and behavioral studies. The lesioned mice exhibited increased spontaneous activity as compared to littermate controls. The lesioned mice were also severely impaired in performance of the retention and cognitive task; they showed decreased passive avoidance retention latencies and increased swim maze latencies as compared to controls. The brains of all of the lesioned mice exhibited cortical morphological abnormalities that ranged from slight to severe. Cortical AChE intensity and distribution in the brains of the lesioned mice, however, were comparable to those of controls. In correlation studies of behavioral and morphological data, motor activity did not correlate with either passive avoidance retention or swim maze latencies. Additionally, cortical cytoarchitectural abnormalities did not correlate with motor activity. Cortical cytoarchitectural abnormalities did, however, correlate with both passive avoidance and swim maze latencies, i.e. severely abnormal cortical morphology predicted low passive avoidance retention latencies and high swim maze latencies. These data indicate that cortical cytoarchitectural abnormalities resulting from nBM lesions in neonates correlate with impairments on the cognitive task, but not with the activity measures, in adult mice. Thus, in this lesion model, and by extrapolation in developmental disabilities in humans, structural changes in the cortex which result from transient disruption of cortical cholinergic innervation may lead to persistent cognitive impairments in adulthood.
Disulfide pairings and secondary structure of porcine β‐microseminoprotein
Authors: Wang Iren , Yu Tsun-Ai , Wu Shih-Hsiung , Chang Wen-Chang , Chen Chinpan
Published: April 2003

A sperm motility inhibitor isolated from porcine seminal plasma is identical to porcine β‐microseminoprotein (MSP). Circular dichroism (CD) and nuclear magnetic resonance (NMR) data showed that the native and recombinant porcine MSPs exhibit very similar structure. The five disulfide pairings on porcine MSP were unambiguously assigned based on NMR data and further confirmed using structural calculations. Surprisingly, our derived pairings differ from those recently reported for ostrich MSP based on matrix‐assisted laser desorption ionization‐time of flight (MALDI‐TOF) analysis. Furthermore, the secondary structure was determined to comprise one four‐stranded and two double‐stranded antiparallel β‐sheets. As we know, this is the first detailed secondary structure reported among several types of MSPs.
Palmitate acutely raises glycogen synthesis in rat soleus muscle by a mechanism that requires its metabolization (Randle cycle)
Authors: Massao Hirabara Sandro , de Oliveira Carvalho Carla Roberta , Mendonça José Roberto , Piltcher Haber Esther , Fernandes Luiz Claudio , Curi Rui
Published: April 2003

The acute effect of palmitate on glucose metabolism in rat skeletal muscle was examined. Soleus muscles from Wistar male rats were incubated in Krebs–Ringer bicarbonate buffer, for 1 h, in the absence or presence of 10 mU/ml insulin and 0, 50 or 100 μM palmitate. Palmitate increased the insulin‐stimulated [14C]glycogen synthesis, decreased lactate production, and did not alter D‐[U‐14C]glucose decarboxylation and 2‐deoxy‐D‐[2,6‐3H]glucose uptake. This fatty acid decreased the conversion of pyruvate to lactate and [1‐14C]pyruvate decarboxylation and increased 14CO2 produced from [2‐14C]pyruvate. Palmitate reduced insulin‐stimulated phosphorylation of insulin receptor substrate‐1/2, Akt, and p44/42 mitogen‐activated protein kinases. Bromopalmitate, a non‐metabolizable analogue of palmitate, reduced [14C]glycogen synthesis. A strong correlation was found between [U‐14C]palmitate decarboxylation and [14C]glycogen synthesis (r=0.99). Also, palmitate increased intracellular content of glucose 6‐phosphate in the presence of insulin. These results led us to postulate that palmitate acutely potentiates insulin‐stimulated glycogen synthesis by a mechanism that requires its metabolization (Randle cycle). The inhibitory effect of palmitate on insulin‐stimulated protein phosphorylation might play an important role for the development of insulin resistance in conditions of chronic exposure to high levels of fatty acids.
Structural, functional analysis and localization of the human CAP18 gene
Authors: Larrick James W. , Lee Jaehag , Ma Shihwin , Li Xu , Francke Uta , Wright Susan C. , Balint Robert F.
Published: April 2003

CAP18 is an antimicrobial protein found in specific granules of PMNs. The human CAP18 (HCAP18) gene was cloned from a human genomic phage library. Sequence analysis revealed the HCAP18 gene to have 4 exons spanning 3 kb, including 700 bp of upstream DNA. Using 3′ RACE no homologs of human HCAP18 were found in human bone marrow or leukocyte populations. By PCR analysis of a somatic cell mapping panel and fluorescence in situ hybridization of a genomic clone to metaphase chromosomes the gene was mapped to chromosome band 3p21.3. Like several other genes expressed late in PMN development the CAP18 gene did not contain typical TATA box or CCAAT sequences. Expression in Cos 7 cells permitted limited mapping of the promoter function in upstream fragments of the HCAP18 gene. Western blot, Northern blot and RT‐PCR analysis show HCAP18 to be produced specifically in granulocytes. This work forms the groundwork for future analysis of the genetic regulation of this antimicrobial protein during PMN differentiation.
An amino acid exchange in the second transmembrane segment of a neuronal nicotinic receptor causes partial epilepsy by altering its desensitization kinetics
Authors: Weiland Sigrid , Witzemann Veit , Villarroel Alfredo , Propping Peter , Steinlein Ortrud
Published: April 2003

The α4 subunit of the neuronal nicotinic acetylcholine receptor is the first gene shown to be involved in a human idiopathic epileptic disease. A missense mutation, leading to the replacement of serine 248 by phenylalanine in the second transmembrane segment, had been detected in patients with autosomal dominant nocturnal frontal lobe epilepsy. The properties of the wild type receptor composed of α4 and β2 subunits and the mutant receptor where α4 subunits carried the mutation at serine 248 were compared by means of cDNA manipulation and expression in Xenopus oocytes. The mutant receptor exhibited faster desensitization upon activation by acetylcholine and recovery from the desensitized state was much slower than in the wild type receptor. We conclude that the reported mutation causes seizures via a diminution of the activity of the α4β2 neuronal nicotinic acetylcholine receptor.
A recombinant polypeptide model of the second predicted nucleotide binding fold of the cystic fibrosis transmembrane conductance regulator is a GTP‐binding protein
Authors: Randak Christoph , Neth Peter , Auerswald Ennes A. , Assfalg-Machleidt Irmgard , Roscher Adelbert A. , Hadorn Hans-Beat , Machleidt Werner
Published: April 2003

Association reactions of a recombinant CFTR‐NBF‐2 polypeptide fused to glutathione S‐transferase with guanine nucleotides were monitored quantitatively by recording the fluorescence enhancement of excited trinitrophenol (TNP)‐labelled GTP after binding to NBF‐2. Binding of TNP‐GTP to the recombinant NBF‐2 polypeptide was characterized by a K
d value of 3.9 μM. The corrected K
d values for unlabelled guanine nucleotides were determined to be 33 μM for GTP, 92 μM for GDP and 217 μM for GMP. TNP‐ATP bound to NBF‐2 was competitively displaced by GTP indicating a common binding site for both nucleotides. The recombinant NBF‐2 did not show an intrinsic GTPase activity above a detection limit of 0.007 min−1. Our findings provide the first experimental evidence that NBF‐2 can act as a GTP‐binding subunit that would favor the release of GDP after GTP hydrolysis.
Analysis of the characteristics of projects in diverse industries
Authors: Tukel Oya Icmeli , Rom Walter O.
Published: April 2003

Solution procedures for resource‐constrained project scheduling problems are usually validated using simulated data. In many cases, however, a technique that provides quality schedules for simulated data performs poorly on actual projects, because the simulated data might not reflect all the characteristics of real projects. Furthermore, projects in various industries might possess different characteristics. In this paper, we analyze the responses to an empirical study of project managers. The survey was conducted nationwide, and was designed to identify and categorize characteristics of projects in various industries as well as performance measures and constraints. A variety of statistical techniques are used to describe project profiles, ranging from simple descriptive statistics to multivariate analysis. The results demonstrate that while many common project characteristics exist, there are noticeable differences in projects across industries. Some unexpected results are discovered, especially related to project managers' objectives and the constraints they are subject to in establishing schedules. For example, for many project managers, maximizing project quality is more important than other scheduling objectives examined in the literature. Furthermore, results show that project managers are constrained by the availability of labor resources more often than other types of constraints, such as budget or raw materials.
Expression of urokinase‐type plasminogen activator and its receptor is up‐regulated during tendon healing
Authors: Xia Wei , de Bock Charles , Murrell George A. C. , Wang Yao
Published: April 2003

The urokinase‐type plasminogen activator (uPA) system has been implicated in cell migration, angiogenesis, extracellular matrix synthesis and tissue remodelling. However, little is known about the role of the system in tendon healing. We used a rat Achilles tendon model to study mRNA and protein expression of uPA and its receptor (uPAR) during tendon healing using immunohistochemical, Northern and Western blot analyses. Time‐dependent increases in uPA/uPAR mRNAs and proteins, maximal on days 4–7 and 7–14 respectively, were found following Achilles tendon division. Interestingly, uninjured control tendons expressed uPA mRNA and protein, but little uPAR transcripts and protein. On day 14 following Achilles tendon division, uPA receptor protein increased 12.6‐fold (p < 0.001) while uPA itself increased only 1.3‐fold (p < 0.05). Immunohistochemical analyses revealed that both uPAR/uPA positive staining cells were increased in the healing tendon tissue section. These findings show for the first time that uPA, and especially its receptor uPAR, are up‐regulated during tendon healing. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Reliability and Validity of the Greek Version of the STAIC
Authors: Psychountaki Maria , Zervas Yannis , Karteroliotis Konstantinos , Spielberger Charles
Published: April 2003

Summary: This study describes the adaptation of the State-Trait Anxiety Inventory for Children (STAIC; Spielberger, Edwards, Lushene, Montuori, & Platzek, 1973 ) to the Greek population. It was hypothesized that the STAIC would be able to measure children's state-trait anxiety levels. In the initial phase, a sample of 100 children, aged 9-12 years, was used in order to shape the final form of the inventory. In the final phase, two different samples (N = 875), aged 9-12 years, were used to test the validity and reliability of the inventory, using exploratory (Sample A; n = 425) and confirmatory (Sample B; n = 450) factor analyses. The results indicated that both scales possessed an acceptable internal consistency and reliability. The factor analysis in the total of the items indicated three factors, that is “absence of state anxiety,” “presence of state anxiety,” and “trait anxiety.” Also, confirmatory factor analysis (AMOS; Arbuckle, 1997 ) verified three factors. It is therefore concluded that the scales have a multifactorial structure and can be used among the Greek population to examine children's state and trait anxiety levels.
Nonlinear dispersion relation of ultra-relativistic plasma waves
Authors: Jovanović Moma S. , Dimitrijević Dejan R.
Published: April 2003

The results of study of ultra-intense electron plasma wave propagation in an infinite and uniform plasma are presented. The dispersion equation for arbitrary wave amplitude and moderate plasma temperature is derived. This equation is solved for various field intensities including strongly relativistic ones. The dispersion relation validity limit is indicated, on account of possible wavebreaking that changes the dispersion properties.
Enhanced conversion of thermal electron Bernstein waves to the extraordinary electromagnetic mode on the National Spherical Torus Experiment
Authors: Taylor G. , Efthimion P. C. , Jones B. , LeBlanc B. P. , Wilson J. R. , Wilgen J. B. , Bell G. L. , Bigelow T. S. , Maingi R. , Rasmussen D. A. , Harvey R. W. , Smirnov A. P. , Paoletti F. , Sabbagh S. A.
Published: April 2003

A fourfold increase in the conversion of thermal electron Bernstein waves (EBW) to the extraordinary mode (X mode) was measured when the density scale length (Ln) was progressively shortened by a local boron nitride limiter in the scrape-off of an Ohmically heated National Spherical Torus Experiment plasma [M. Ono, S. Kaye, M. Peng et al., Proceedings of the 17th IAEA Fusion Energy Conference (IAEA, Vienna, 1999), Vol. 3, p. 1135]. The maximum conversion efficiency approached 50% when Ln was reduced to 0.7 cm, in agreement with theoretical predictions that used locally measured Ln. Calculations indicate that it is possible to establish Ln<0.3 cm with a local limiter, a value predicted to attain ∼100% EBW conversion to the X mode in support of proposed EBW heating and current drive scenarios.
Collisional diffusion in a two-dimensional point vortex gas or a two-dimensional plasma
Authors: Dubin Daniel H. E.
Published: April 2003

This paper analyzes collisional diffusion of a multispecies two-dimensional (2D) point vortex gas, or a 2D plasma, in the presence of retrograde shear. Diffusion both along and across the shear flow is calculated using Boltzmann, Kubo, Klimontovitch and resonance-broadening theories. It is shown that diffusion is reduced in the presence of shear, just as for the shear reduction of transport observed in fusion plasmas. Here, however, fluctuations are thermal rather than turbulent, allowing a rigorous calculation of the transport. When there are several species of point vortices, Onsager relations require that the diffusive flux conserves the total vorticity ρ(r), which is proportional to charge density in the plasma analogue. Surprisingly, the diffusive flux concentrates vortices with large positive (or negative) circulations at maxima (or minima) of the mean vorticity profile.