bluuebunny/crossref_metadata_2025 huggingface dataset:
Postnatal development of the excitatory amino acid system in visual cortex of the rat. Changes in ligand binding to NMDA, quisqualate and kainate receptors
Authors: Erdö Sandor L. , Wolff Joachim R.
Published: April 2003

The postnatal development of the ligand binding to N‐methyl‐d‐aspartate (NMDA), quisqualate and kainate receptor sites was examined in whole homogenates of the visual cortex of rats, aged 2–360 days. As selective ligands, [3H]CPP (3‐(2‐carboxypyperazine‐4‐yl)‐propyl‐1‐phosphonic acid, [3H]AMPA (RS‐alpha‐amino‐3‐hydroxy‐5‐methyl‐isoxazole‐4‐propionic acid) and [3H]KA (kainic acid) were used, respectively. The binding of CPP was low in newborns, rapidly increased from the second postnatal week, reached its maximum between weeks 2 and 3, then slowly declined up to the age of 1 year. In contrast, the binding of AMPA and kainate was high perinatally, increased rapidly up to day 6 after birth to reach an early maximum value, then gradually decreased to adult values which were attained at an age of 3–4 weeks. These age‐related changes were derived from alterations in the density of binding sites, which, in the case of AMPA, was accompanied by an increase in binding affinity. The results, compared with the developmental time‐course of excitatory synapses, indicate that, in the immature cerebral cortex, NMDA receptors may be primarily involved in synaptic transmission, whereas quisqualate and kainate receptors may play some other (e.g. trophic) roles.
Aging increases calcium influx at motor nerve terminal
Authors: Alshuaib Waleed B. , Fahim Mohamed A.
Published: April 2003

To determine whether increased transmitter release from soleus nerve terminals of old C57BL/6J mice is caused by an altered Ca2+ regulation, the time course of post‐tetanic potentiation of miniature endplate potential (MEPP) frequency was used as an indicator of the kinetics of Ca2+ metabolism in young (10 months) and old (24 months) mice. Post‐tetanic potentiation properties were studied in either (1) 0.2 mM Ca2+, 5.0 mM Mg2+ Krebs; or (2) Ca2+‐free/EGTA Krebs to eliminate Ca2+ influx, and thereby isolated Ca2+ buffering. In the 0.2 mM Ca2+ Krebs, the time constants of decay of augmentation (TA) and potentiation (TP) were longer in old (TA = 10.3 ± 1.0 sec, TP = 195.3 ± 5.4 sec) than in young (TA = 7.0 ± 0.7 sec, TP = 78.8 ± 6.6 sec) nerve terminals. Evoked transmitter release was measured in 0.4 mM Ca2+, 2.75 mM Mg2+ Krebs. Quantal content of the endplate potential was positively correlated with TA (r = 0.95) and with TP (r = 0.98). In the Ca2+‐free/EGTA Krebs, there was no difference in post‐tetanic potentiation properties between young and old terminals. These results suggest that Ca2+ influx into the soleus nerve terminal increases with aging. This may explain, at least in part, the increased quantal content observed at old terminals.
Glia protect hippocampal neurons against excitatory amino acid‐induced degeneration: Involvement of fibroblast growth factor
Authors: Mattson Mark P. , Rychlik Barbara
Published: April 2003

Low density cell cultures of embryonic rat hippocampus containing astrocyte‐like glia and neurons were used to test the hypothesis that glia can alter ‘natural’ and excitatory amino acid (EAA)‐induced neuronal death. Neurons contacting glia survived for longer time periods than did neurons not contacting glia. Neurons associated with glia were also protected against glutamate and kainate neurotoxicity. Fibroblast growth factor (FGF)‐like immunoreactivity was associated with the glia. Addition to the cultures of an antiserum raised against an internal peptide fragment of FGF greatly reduced the protective effect of glia against both spontaneous and EAA‐induced neurotoxicity. Contact with glia, or exposure to exogenous FGF, also protected the hippocampal neurons against Ca2+ ionophore‐induced degeneration indicating that FGF enhanced the ability of neurons to handle a Ca2+ load. Taken together, these results suggest that glia surface‐associated FGF may play important roles in hippocampal development, and in neurodegenerative conditions that involve EAAs.
Regional ontogeny of a unique glutamate recognition site in rat brain: An autoradiographic study
Authors: Greenamyre J. Timothy , Higgins Donald S. , Young Anne B. , Penney John B.
Published: April 2003

The developmental pattern of l‐[3H]glutamate binding to rat brain in the presence of saturating concentrations of unlabeled N‐methyl‐d‐aspartate (NMDA), kainate (KA) and quisqualate (OQA) was examined in an autoradiographic assay. The unique glutamate binding site defined by this assay displayed four distinct, regionally specific patterns of development. (1) In reticular nucleus of thalamus there was an initial very high level of binding at postnatal day 1 (PND1) followed by a progressive 80% decline in binding during maturation. (2) In entorhinal cortex, a progressive 500–1100% increase in binding was seen during development. (3) In ventral posterior medial nucleus of thalamus, there was an initial transient 200–300% increase in binding, peaking at PND10, followed by a steady decline in binding. (4) In frontal cortex, binding remained relatively stable throughout development. At all stages of development, the distribution of these recognition sites was different from NMDA, KA or QQA receptors. The function of this glutamate binding site remains to be determined, but the distinct regional and temporal patterns of binding suggest that it may be important in normal development of the central nervous system.
Fetal alcohol effects: Decreased synaptic formations in the field CA3 of fetal hippocampus
Authors: Tanaka Harumi , Nasu Fumio , Inomata Kenichirou
Published: April 2003

The effects of prenatal ethanol exposure on the synaptic formation in the field CA3 of the hippocampus of fetal rats have been investigated on gestational day 21. Significantly decreased number of synaptic junctions was observed in the fetus showing decreasing cerebral weight either with or without decreasing body weight. The administration of 0.01% zinc with ethanol or 0.02% α‐tocopherol acetate with ethanol during pregnancy resulted in an increased cerebral weight, but did not result in an increased synaptic formation compared to ethanol alone. This result indicates that one of the most vulnerable factors in rat fetus exposed to ethanol in utero is the synaptic formation in the hippocampus. In conclusion, ethanol exposure in utero during a period of brain development roughly equivalent to the first and second human trimesters can produce consistent dysforming effect of synapses and may be associated with the functional impairment of the central nervous system in the fetal alcohol effects.
Chronic blockade of bioelectric activity in neonatal rat neocortex in vitro: Physiological effects
Authors: Baker Robert E. , Ruijter Jan M.
Published: April 2003

We have examined what effect the loss of spontaneous bioelectric activity has on neural network formation in organotypic rat neocortical explants grown under serum‐free culture conditions. Explants were taken from dorsal midline (presumptive visual) and lateral (presumptive auditory) occipital cortex and chronically exposed to tetrodotoxin which blocked all measurable bioelectric activity between change of medium. Extracellular recordings revealed complex, rhythmic spontaneous and evoked multiunit discharges in all explants examined (following tetrodotoxin washout in the experimental group). Control auditory explants had significantly more sites from which electric activity could be recorded compared with control visual explants. Auditory cultures showed no effect of the tetrodotoxin treatment, whereas visual explants showed significant increases over control values, equalling the auditory values. This increased level of spontaneous bioelectric activity was maintained for at least 10 days following transfer of the cultures to control growth medium. There was no significant difference between control visual and auditory explants regarding the number of sites from which evoked activity was seen. Nor did either cortex group show an effect of tetrodotoxin on the number of sites from which evoked activity was seen. The frequency with which spontaneous bioelectric discharges occurred per site increased with age in auditory vs visual cortex. These differences, however, were abolished in the tetrodotoxin‐treated groups. It was concluded that neocortical explants which have experienced chronic suppression of spontaneous electric activity did not suffer deficits in neural network formation, though there is an effect on the incidence and frequency with which such activity is given.
Muscle‐derived factors enhance cholinergic neuronal expression in the chick embryo—II. In culture studies
Authors: Brodie Chaya , Vernadakis Antonia
Published: April 2003

The effects of muscle‐derived factors on the cholinergic and GABAergic neuronal phenotypes were studied in cultures derived from 3‐day‐old whole chick embryo (E3WE) consisting of proliferating neuroblasts and 8‐day‐old chick embryo cerebral hemispheres (E8CH) consisting of differentiated neurons. The effects of limb muscle extract (LME) were examined either when added to the culture medium or to the polylysine coating substratum cultures. We also compared the effects of LME derived from 8‐ to 15‐day‐old chick embryos. We found that LME added to the medium not only increased choline acetyltransferase activity, a marker for cholinergic neurons throughout the development of neurons in E3WE or E8CH culture, but also delayed the decline in the activity observed in untreated cultures. The marked increase in choline acetyltransferase activity in E8CH cultures grown on substratum‐bound LME as compared to those grown in medium‐containing LME, suggests that LME factors may be adhesion‐promoting substances stimulating neuronal growth. These findings provide evidence that muscle‐derived factors may be important in early cholinergic phenotypic expression and support our previous in ovo studies indicating that target‐derived factors in limb muscle extract have general cholinotrophic effect.
Matrigel enhances myotube development in a serum‐free defined medium
Authors: Lyles Joan M. , Amin Waheeda , Weill Cheryl L.
Published: April 2003

Previously reported serum‐free defined media for muscle cell culture require supplementation with hormones, purified growth factors or attachment factors. This report describes a culture system that enhances embryonic chick, skeletal muscle cell growth and differentiation in a serum‐free defined medium, without added specialized trophic factors. Myoblasts adhered more to and proliferated more rapidly on a reconstituted basement membrane substrate, Matrigel, than on rat‐tail collagen. Matrigel contains several basement membrane attachment molecules which apparently obviate the need for added purified attachment factors. Matrigel also appeared to play a trophic role in subsequent development by enabling the serum‐free growth of myotubes which suggests that Matrigel mediates the cellular interaction of growth or attachment factors. Collagen, on the other hand, did not support serum‐free myotube growth. Supplementation of defined medium with increasing levels of horse serum enhanced total protein in myotubes grown on both substrates; protein was higher in Matrigel cultures for each medium tested. The serum‐free defined medium supported complete morphological differentiation of myotubes grown on Matrigel and maintained myotube cultures up to 22 days. Fibroblast proliferation was higher in cultures on collagen in defined medium with high serum levels, but was virtually eliminated in cultures on Matrigel in serum‐free defined medium. The culture system described supports the differentiation of embryonic muscle cells in a simple, serum‐free defined medium, thus providing an in vitro model of developing myotubes which should be particularly useful for studies of regulation mediated by extracellular factors.
Distribution of cholinergic neurons in the chick spinal cord during embryonic development. Comparison of ChAT immunocytochemistry with AChE histochemistry
Authors: Thiriet G. , Kempf J. , Ebel A.
Published: April 2003

The location of cholinergic neurons was studied during the development of the chick embryo spinal cord. A comparison between choline acetyltransferase (ChAT) immunocytochemistry and acetylcholinesterase (AChE) histochemistry was performed. ChAT‐positive neurons could be detected only from embryonic day 9 (E9) onwards by the FITC technique and from E12 onwards by the PAP technique. These neurons were located mainly in the medial and lateral motor columns in the ventral horn of the gray matter and some of them were observed in the intermediate region of the spinal cord. AChE‐containing cell bodies were much more numerous than the ChAT immunoreactive ones and were distributed in the ventral horn of the gray matter, the intermediate gray region and mostly off the apical part of the dorsal horn. ChAT should provide a reliable and specific marker for cholinergic neurons.
Effect of the substrate on neurofilament phosphorylation in mixed cultures of rat embryo spinal cord and dorsal root ganglia
Authors: Dahl D. , Gilad V.H. , Maggini L. , Bignami A.
Published: April 2003

The effect of the substrate on neurofilament phosphorylation was studied in primary cultures of spinal cord and dorsal root ganglia dissociated from 15‐day‐old rat embryos. On polylysine and Primaria® substrates, spinal cord neurons formed aggregates connected by bundles of neurites. (Primaria® dishes have a modified plastic surface with a net positive charge.) On both polylysine and Primaria® substrates, spinal cord neurons were stained with neurofilament monoclonal antibodies reacting with phosphorylated epitopes appearing early in rat embryo development, i.e. soon after neurofilament expression. Conversely, immunoreactivity with antibodies recognizing late phosphorylation events was only observed on Primaria® substrates. As reported by many investigators, fibronectin and laminin were excellent substrates for dorsal root ganglia neurons in culture. However, on both laminin and fibronectin substrates immunoreactivity with antibodies recognizing late phosphorylation events, only occurred after several days in culture, at a time when non‐neuronal cells (mainly astrocytes) had formed a confluent monolayer.
Effects of combined pre‐ and postnatal ethanol exposure (three trimester equivalency) on glial cell development in rat optic nerve
Authors: Phillips D.E. , Krueger S.K.
Published: April 2003

This study evaluated the effects of a combined gestational and 10 day postnatal alcohol exposure (human three trimester equivalency) on the development of glial cells in the rat optic nerve. Pregnant rats were exposed to alcohol via a liquid diet, then their pups were artificially reared and further exposed to alcohol for 10 postnatal days via a gastrostomy fed liquid diet. Control animals, born of pair fed dams, were artificially reared on pair fed isocaloric diets. Optic nerve tissues were prepared for light and electron microscopic studies from animals on gestational days (G) 15 and 20 and postnatal days (P) 5, 10, 15, 20 and 90. There were fewer glial cells per cross‐section on day 15 and the crosssectional areas of optic nerves were smaller on days G20, P15 and P90 in the ethanol exposed animals. There was an alcohol‐induced delay in the appearance of immature cells within the oligodendroglia lineage and a decrease in the number of oligodendroglia present at 15 and 20 days, indicating a delay in the maturation of oligodendroglial cells. These effects were compensated for by 90 days. Maturation of the astrocytic cell lineage was generally unaffected by the alcohol although there was evidence of increased numbers of cells in the lineage. There was no consistent indication of alcohol‐induced degeneration of glial cells or their organelles. Thus, alcohol exposure for all of gestation and 10 postnatal days in the rat causes a delay in oligodendrocyte maturation but appears to have no long‐term effects on the glial cell population of the optic nerve. Such a delay, by contributing to delays in myelin development, could help to explain some of the neurological dysfunctions associated with developmental alcohol exposures.
Effect of gamma‐glutamyl transpeptidase inhibitors on the transport of glutamate into neuronal and glial primary cultures
Authors: Jankásková B. , Lisý V. , Šťastný F.
Published: April 2003

Inhibitors of gamma‐glutamyl transpeptidase (mixture of serine and borate — 13 mM, kainic acid — 5 mM and 6‐diazo‐5‐oxo‐L‐norleucine — 2 mM) significantly suppressed glutamate uptake into cultured neurones and glial cells. The simultaneous application of any of these inhibitors with ouabain resulted in a further decline in glutamate uptake. It can be speculated that gamma‐glutamyl transpeptidase significantly contributes to glutamate transport into nerve cells in the early period of brain development until the Na+‐K+‐gradient is fully constituted.
Effect of CDP‐choline treatment on mitochondrial and synaptosomal protein composition in different brain regions during aging
Authors: Villa Roberto F. , Ingrao Francesca , Magri Grazia , Gorini Antonella , Reale Salvatore , Costa Antonino , Ragusa Nicolo' , Avola Roberto , Giuffrida‐Stella Anna Maria
Published: April 2003

Several age‐dependent modifications of inner mitochondrial membrane and synaptosomal plasma membrane proteins from different brain regions of 4‐, 12‐, 18‐ and 24‐month‐old male Wistar rats, were observed. Some proteins, identified by immunoblotting assay as various subunits of mitochondrial respiratory chain complexes and calmodulin, were particularly impaired. Chronic treatment with CDP‐choline at a dose of 20 mg/kg body weight per day for 28 days caused significant changes in the amounts of several of the above mentioned proteins. Most of the proteins, which decreased during aging, showed a significant increase after CDP‐choline treatment compared with the corresponding control values at the same age. The effect of CDP‐choline might be due to: — the increased availability of cytidylic nucleotides, which in the brain are present in limited amounts compared to the other nucleotides; — the increased content of total adenine nucleotides; —the improvement of brain energy metabolism.
Migration pathways, differentiation and survival of macroglial cells from a xenograft implanted into the thalamus of newborn mice
Authors: Quinonero J. , Colin C. , Villarroya H. , Collins P. , Jacque C.
Published: April 2003

Embryonic rabbit corpus callosum transplants were grafted into the thalamus of newborn shiverer mice in order to compare the fates of oligodendroglial and astroglial cells derived from the transplants. Our model allowed the identification of the two populations of macroglial cells. The thalamus was chosen as site of implantation because of its situation at a crossroad of numerous neuronal fascicles. Previous studies, where the dorsal striatum was used as site of implantation, had shown that corpus callosum was one of the favorite routes of migration for both populations of macroglial cells. In the present study special attention was given to the comparison of the migration pathways and areas of settlement of implanted astroglia and oligodendroglia. The internal capsule, the medial lemniscus, the crus cerebri and the thalamic radiations were used by both populations of transplant derived macroglial cells for their migrations through the host parenchyma. They integrated into the host tissue on these routes or further away in areas such as the putamen, the mesencephalon or the colliculi. Signs of degeneration of the implanted astroglia were often observed after 1 month post‐implantation.
Transplantation of cultured type 1 astrocyte cell suspensions into young, adult and aged rat cortex: Cell migration and survival
Authors: Andersson Candace , Tytell Michael , Brunso‐Bechtold Judy
Published: April 2003

The present study examined the fate and migration of transplanted astrocytes in different host ages. Additionally, the effect of donor cell age was examined in relation to cell migration. Cultured astrocytes from 5,12 and 30 days in vitro were transplanted into young (postnatal day 5 and 21), adult (4.5 month), and aged (21 month) animals. The transplanted cells were labeled with Fast Blue, Fluorogold or DiI. The results confirmed previous studies demonstrating that transplanted cells were able to migrate successfully through host central nervous system and extended those findings to show that the age of the host significantly influenced donor cell migration distance. Migration was most extensive in young animals, as conditions supporting cell migration appeared to be lacking in older animals. Donor cells preferentially migrated on myelinated fiber tracts, rather than on unmyelinated fiber tracts or gray matter. The donor cells were not glial fibrillary acidic protein positive, indicating that either the cultured type 1 astrocytes did not survive transplantation or underwent significant remodeling of the intermediate filament network. It is also possible that a subpopulation of cells, possibly immature astrocytes which are present in the transplanted cell suspensions, flourished and subsequently migrated in the host brains.
Directed migration of transplanted glial cells toward a spinal cord demyelinating lesion
Authors: Gout O. , Dubois‐Dalcq M.
Published: April 2003

To investigate the migration of transplanted glial cells in normal adult mice with a focal demyelinating lesion, we have used A2G mice which have the autosomal dominant Mx‐1 allele as donor. Mx‐1 protein expression is inducible by interferon and is detected in a dotted pattern in the nucleus of A2G cells. A/J mice were used as recipient animals as they express the same major histocompatibility antigens as A2G but cannot express the Mx‐1 protein. An acute demyelinating lesion was produced in the A/J spinal cord by intraspinal injection of lysolecithin. Mixed glial cultures derived from newborn A2G brain were treated with α/β interferon for 24 hr. These Mx‐1 expressing glial cells were then transplanted two intervertebral spaces away from the demyelinating lesion. The fate of the grafted cells was followed over the next 13 days, during which the induced Mx‐1 protein can still be detected by immunocytochemistry. Grafted cells were found between the transplantation site and the lesion at 24 hr and some of the Mx‐1+ cells reached the lesion at 4 days. The majority of the Mx‐1+ migrating cells expressed GFAP and were located in the myelinated white matter and around the blood vessels. Scattered MBP+, Mx‐1+ cells were detected in the lesion indicating that some of the transplanted cells may participate in the repair process. The Mx‐1 is a useful marker to follow the migration events in the days after grafting and to determined what factors may attract transplanted cells toward a demyelinating lesion.
The migratory potential of vitally labelled microglial cells within the retina of rats with hereditary photoreceptor dystrophy
Authors: Thanos Solon , Richter Waltraud
Published: April 2003

We employed a recently developed technique of labelling retinal microglial cells to identify these cells within the retinal parenchyma and to determine their role during degenerative diseases. In a first set of experiments we retrogradely labelled the ganglion cells from the superior colliculus of neonatal pups of the royal college of surgeons (RCS)‐strain with the fluorescent dye 4Di‐10ASP [N‐4‐4‐(4‐didecylaminostyryl‐N‐methylpropidium iodide)] at the day of birth. In a second group of young rats of the same strain retrograde staining of ganglion cells was performed by applying the fluorescent dye at the cross‐sectional area of the transected optic nerve. In both experimental groups, prelabelled ganglion cells die. In the neonatal rats ganglion cells disappear because the initial neuronal cell population becomes naturally reduced by about 35% in the course of the programed cell death, which takes place during the first 2 weeks of life. In the mature rat, ganglion cells die as a consequence of the axotomy. In both cases, the fluorescent dye, which is a lipid inserted into the cell membrane, labels the ganglion cell bodies after retrograde transport from the axons. In the course of their degradation the dye is then selectively taken up by intraretinal microglial cells in the ganglion cell and inner plexiform layers. In both groups of experiments, fluorescently labelled microglial cells were redistributed from the inner retina toward the photoreceptor cell layer, which is afflicted by chronic photoreceptor dystrophy. Similar migration does not occur when the same experiments were repeated with non‐dystrophic normal rats. The experimental results suggest that intraretinal microglial cells possess a migratory potential and make use of it when the cells are exposed to degeneration‐induced stimuli, the nature of which remains to be characterized.
Migratory, invasive and metastatic capacity of NCAM transfected rat glioma cells
Authors: Edvardsen Klaus , Brünner Nils , Spang‐Thomsen Mogens , Walsh Frank S. , Bock Elisabeth
Published: April 2003

A cDNA encoding a transmembrane 140 kDa isoform of the neural cell adhesion molecule, NCAM, was transfected into the rat glioma cell line BT4Cn. Transfectants with a homogeneously high expression of NCAM‐B showed a decreased capacity for penetration of an artificial basement membrane when compared to cells transfected with expression‐vector alone or untransfected cells. However, when injected subcutaneously into nude mice, both NCAM expressing cells and control cells produced invasive tumors. Nude mice injected with NCAM positive cells developed tumors with slower growth rates as compared to those induced by NCAM negative cells. This implies that NCAM may not only be involved in adhesive and motile behaviour of glioma cells, but also in their growth regulation.
Migration of human malignant astrocytoma cells in the mammalian brain: Scherer revisited
Authors: Laws Edward R. , Goldberg William J. , Bernstein Jerald J.
Published: April 2003

Fresh suspensions of human glioblastoma multiforme were preincubated in the plant lectin Phaseolus vulgaris leucoagglutinin (PHAL) and implanted into cortical pockets in adult rat brain. Brains were investigated periodically over 30 postoperative days and the migration of the human glioblastoma cells was traced with anti‐PHAL immunofluorescence or the overexpression of human specific p185c‐neu a specific marker of a class of human malignant astrocytoma cells. The principal pathway of migration of the implanted human cells in the rat brain was ventrally through cortical gray matter and into the corpus callosum, with rapid lateral distribution in this and other parallel and intersecting white matter fascicles. Human glioblastoma cells also migrated on basement membrane lined blood vessels, pia‐glia membrane and spaces of Virchow‐Robin, as well as the subependymal space of the ventricles. These paths of migration of human glioblastoma cells in the rat brain are consistent with the pathways of spread of glioblastoma in the human brain as described by Scherer over 50 years ago, indicating that multifocal malignant astrocytomas have common migratory pathways in mature mammalian brain.
Neuropeptides in dissociated cell cultures of mammalian spinal cord and dorsal root ganglion
Authors: Matthew E.
Published: April 2003

Immunohistochemical studies of leucine‐enkephalin, somatostatin, vasoactive intestinal polypeptide and neurotensin were carried out in dissociated cell co‐cultures of embryonic mouse spinal cord and dorsal root ganglion, using the peroxidase‐antiperoxidase technique. Leucine‐enkephalin immunoreactivity exceeded that of the other peptides in these coculture preparations. Leucine‐enkephalin, substance P and somatostatin were also studied in spinal cord cultures (without dorsal root ganglia) and in dorsal root ganglia cultures (without spinal cord). Each of these peptides was present in only a small percentage (<10%) of perikarya and processes in spinal cord cultures. No leucine‐enkephalin immunoreactivity was seen in dorsal root ganglion cultures; a considerable proportion of the processes were immunoreactive for substance P or somatostatin. These observations suggest that co‐cultures of spinal cord and dorsal root ganglia can provide a simplified in vitro “model” of the nervous system for the study of peptidergic interactions.
Nuclear patterns of apoptotic and developing neurons of superior cervical ganglion of newborn rat
Authors: Diana Andrea , Setzu Mariella , Sirigu Silvia , Diaz∗ Giacomo
Published: April 2003

Superior cervical ganglion (SCG) neurons of female rats aged 3, 5 and 7 days revealed conspicuous nuclear changes in neurons undergoing postnatal cell death. Several qualitative and quantitative data such as nuclear size and shape, the presence of atypical chromocenters and chromatin textural features discriminated well neurons candidate to degeneration and those advancing in the direction of adult maturation. At least on morphological grounds, postnatal death of SCG neurons appears to be of apoptotic type. The sequence of nuclear events observed enables the recognition of the early stages of involution which prelude neuron degeneration.
Interleukin‐1β and interferon γ interact with fibroblast growth factor‐2 in the control of neuroblastoma cell proliferation and differentiation
Authors: Scheil S. , Lüdecke G. , Unsicker K.
Published: April 2003

Based on our previous observations that neuroblastoma (MB) cells express fibroblast growth factor‐2 (FGF‐2; basic FGF) and respond to it [Janet T. et al. (submitted); Wewetzer K. et al. (1993) J. Neurosci. Res.36, 209–215), we attempted to find to what extent selected cytokines [interleukin (IL)‐1β and interferon γ (IFNγ)] may modulate FGF‐mediated proliferative activity and differentiation. The NB cell lines IMR‐32, SH‐SY5Y, GIMEN and LAN‐1 and colorimetric assays were used for the determination of cell numbers. IL‐1β (and several other ILs, including IL‐1α, −2, −3, and 6) per se did not affect proliferation of any cell line studied. IFNγ inhibited growth of GIMEN and LAN‐1 cells, but was uneffective on IMR‐32 and SH‐SY5Y cells. FGF‐2 was antimitogenic for GIMEN cells. IFNγ reversed and IL‐1β enhanced this antimitogenic effect of FGF‐2. FGF‐2 per se did not affect LAN‐1 cells and did not modulate the growth inhibitory actions of IFNγ on these cells. FGF‐2 induced proliferation of IMR‐32 and SH‐SY5Y cells. This effect was not modulated by IFNγ or IL‐1β. These results suggest a heterogeneous response pattern of human NB cell lines towards the cytokines studied and complex interactions of FGF‐2, IL‐1β and IFNγ.
Regulation by heavy metals and temperature of the human BAG‐3 gene, a modulator of Hsp70 activity
Authors: Pagliuca Maria Gabriella , Lerose Rosa , Cigliano Stefania , Leone Arturo
Published: April 2003

In HeLa cells the expression of the BAG‐3 gene, a member of the BAG family, is regulated by heavy metals and temperature, with kinetics of accumulation of mRNAs similar to Hsp70 and metallothioneins. Western blot assays performed with a polyclonal anti‐BAG‐3 antibody confirmed that higher levels of the protein were present in the cells following heat and metal exposure. By immunofluorescence techniques and cell fractionation assays we demonstrated that following stress BAG‐3 protein concentrated in the rough endoplasmic reticulum and associated with the heavy membrane fraction. The role of BAG‐3 protein during apoptosis and cellular stress is discussed.
In situ observation of mobility and anchoring of PKCβI in plasma membrane
Authors: Saito Kenta , Ito Eiko , Takakuwa Yuichi , Tamura Mamoru , Kinjo Masataka
Published: April 2003

We employed fluorescence correlation spectroscopy (FCS) to analyze the characteristics of biomolecules in living cells. Protein kinase C (PKC) changes its subcellular localization from cytosol to the plasma membrane by its ligand. Using FCS, we found PKCβI labeled with enhanced green fluorescent protein freely diffusing in cytosol. Upon 12‐O‐tetradecanoylphorbol‐13‐acetate activation, a large part of PKCβI is anchored in the plasma membrane but some PKCβI still moves freely near the plasma membrane. These results indicate that a diffusion‐driven transport mechanism is appropriate for the molecular mechanism of the PKCβI localization change.
‘Green’ value chain practices in the furniture industry
Authors: Handfield Robert B , Walton Steve V , Seegers Lisa K , Melnyk Steven A
Published: April 2003

This paper draws on the results of interviews with five environmental managers in the furniture industry to develop a taxonomy of environmentally‐friendly (‘green’) best practices within the operations management value chain. This taxonomy is then extended to develop a group of propositions concerning the role of management in promoting environmentally‐friendly practices. The results suggest that in order to be successful, environmental management strategies must be integrated into all stages of the value chain, which includes all of the processes spanning product design, procurement, manufacturing and assembly, packaging, logistics, and distribution. While the potential for environmental performance improvement in all five of the companies is evident, all of them demonstrated ‘pockets’ of environmentally‐friendly practices (EFP) in different areas of their respective value chain functions. The propositions and results emerging from the analysis also suggests that reacting to regulations is no longer sufficient. World‐class EFP must anticipate and pre‐empt changing environmental regulations and customer expectations, and proactively prepare products, processes and infrastructure for these changes without sacrificing competitive advantage.
Management initiatives and just‐in‐time manufacturing
Authors: McLachlin Ron
Published: April 2003

Numerous benefits have been claimed for firms that implement just‐in‐time (JIT) approaches to manufacturing. While a fair number of Western firms have been successful at such implementations, other firms that could benefit appear to be addressing only a few features rather than the overall philosophy and system. This paper considers whether each of a number of management initiatives is necessary for the implementation of just‐in‐time manufacturing. A case‐based research methodology was used for theory testing at six plants, each which claimed to be implementing just‐in‐time manufacturing. Data were obtained via interviews, questionnaires, direct observation, and collection of documents. Of six management initiatives considered, four were supported as necessary conditions for both JIT flow and JIT quality, as well as for employee involvement. These four are: (1) promotion of employee responsibility, (2) provision of training, (3) promotion of teamwork, and (4) demonstration of visible commitment. The other two management initiatives were rejected as necessary conditions. These are: (1) provision of workforce security, and (2) use of group performance measures. The results also indicated that employee involvement plays a central role in JIT implementation.
Developing measures of time‐based manufacturing
Authors: Koufteros Xenophon A. , Vonderembse Mark A. , Doll William J.
Published: April 2003

Case and industry studies have increased our understanding of time‐base manufacturing and focused our attention on its key component practices. Despite important contributions by Blackburn (1991) and Stalk and Hout (1990), we lack a clear definition of time‐based manufacturing and its relationship to Just‐in‐time (JIT). This study proposes a framework for research on time‐based manufacturing, reports on the development of a set of seven instruments for measuring the key practices, and tests relationships among these practices. The instruments are valid, reliable, and generalizable across industries and firm size. Tests of the structural model confirm Monden's (1983) notion that shop‐floor employee involvement leads to improved manufacturing practices which, in turn, lead to pull production.
Healing ligaments have decreased cyclic modulus compared to normal ligaments and immobilization further compromises healing ligament response to cyclic loading
Authors: Thornton G. M. , Shrive N. G. , Frank C. B.
Published: April 2003

Ligaments help maintain joint stability by resisting excessive strain during the repetitive loading experienced during daily activity. Healing ligaments may be less able to fulfill this role, straining more under equivalent loading than normal ligaments. We examined the cyclic stress‐strain response of normal and healing ligaments to repetitive low loads (<10% of the normal ligament failure strength). Rabbit medial collateral ligaments (MCLs) were surgically gapped in either a unilateral (right MCL; n = 23) or bilateral (right and left MCLs; n = 17) fashion with immobilization of the right hindlimb in the bilateral group. These MCL scars were allowed to heal for 3, 6, and 14 weeks and were cyclic creep tested at 2.2, 4.1, and 7.1 MPa, respectively. Creep test stresses were a constant 30% of the failure strength of non‐immobilized scars at the different healing intervals. Normal MCLs were creep tested at 4.1 and 7.1 MPa (n = 13). The cyclic modulus of the non‐immobilized scars was less than that of normal ligaments. The percent increase in modulus during cycling was greater for scars than for normal ligaments, likely related to increased viscous dissipation or material inferiorities in scars. Furthermore, immobilization significantly decreased the ability of scars to resist strain, with a majority of immobilized scars failing during repetitive loading. Such failures were preceded by a reduction in cyclic modulus indicating damage to the healing ligaments that was predictive of eventual total failure. The implications of this study are that joints with healing ligaments may have increased strain in joint structures while they are under stress, potentially leading to joint instability. Although immobilization could be used temporarily to maintain joint stability, remobilization would likely lead to total failure of the healing ligament. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Alterations in endogenous osteogenic protein‐1 with degeneration of human articular cartilage
Authors: Merrihew Charis , Kumar Bhavna , Heretis Katherine , Rueger David C. , Kuettner Klaus E. , Chubinskaya Susan
Published: April 2003

A synchronized balance between synthesis and breakdown of extracellular matrix (ECM) molecules in normal articular cartilage is disturbed in osteoarthritis (OA). The focus of our study is the anabolic factor, osteogenic protein‐1 (OP‐1) that is expressed in articular cartilage and is able to induce the synthesis of ECM components. The major aim was to investigate both qualitatively and quantitatively endogenous OP‐1 in normal, degenerative, and OA cartilage. Normal and degenerative cartilage was obtained at autopsies from femoral condyles of human organ donors with no documented history of joint disease; OA cartilage was obtained from patients undergoing joint arthroplasty. Appearance of donor cartilage was evaluated by Collins scale, where normal cartilage is assigned grades 0–1, and degenerated cartilage is assigned grades 2–4. OP‐1 mRNA expression was assessed by RT‐PCR; OP‐1 protein (pro‐ and active forms) was qualitatively analyzed by Western blotting and quantified by OP‐1 ELISA. The highest levels of OP‐1 expression (mRNA and protein) were detected in normal cartilage of grade 0. The concentration of OP‐1 protein was about 50 ng per gram cartilage dry weight. With the progression of cartilage degeneration (increased Collins grades and OA) OP‐1 protein was down‐regulated up to 9‐fold. These changes affected primarily the active form of OP‐1. OP‐1 message also declined in cartilages with the increase of degenerative changes. In conclusion, an overall decrease in endogenous OP‐1 in degenerated and OA tissue suggests that OP‐1 could be one of the factors responsible for normal homeostasis and matrix integrity in cartilage. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Tardive dyskinesia is not associated with the polymorphisms of 5-HT2A receptor gene, serotonin transporter gene and catechol-o-methyltransferase gene ⋆
Authors: Herken Hasan , Erdal M. Emin , Böke Ömer , Savaş Haluk A.
Published: April 2003

Background

The pathophysiology of tardive dyskinesia (TD) is not completely
understood.

Aim

To assess the relationship of TD with 5-HT2A receptor gene, serotonin transporter gene (5 HTT), and catechol-o-methyltransferase (COMT) gene polymorphisms.

Methods

Our study comprised 111 unrelated subjects who strictly met DSM-IV criteria for schizophrenia and 32 TD, and 79 healthy unrelated controls; all the subjects were of Turkish origin. The analyses of 5-HT2A receptor gene, 5 HTT gene, and COMT gene polymorphisms were performed using polymerase chain reaction (PCR) technique.

Results

The polymorphisms of these genes were not significantly different between the schizophrenic patients, TD and control subjects.

Conclusions

Our findings indicated that 5-HT2A receptor gene, 5 HTT gene, and COMT gene polymorphisms were similar in schizophrenia with non-TD, schizophrenia with TD, and healthy controls. These polymorphisms, though, do not help to evaluate the susceptibility to TD.
Is interval medication a successful treatment regimen for schizophrenic patients with critical attitudes towards treatment?⋆
Authors: Godemann F. , Linden M. , Gaebel W. , Köpke W. , Müller P. , Müller-Spahn F. , Tegeler J. , Pietzcker A.
Published: April 2003

In neuroleptic long-term medication, only part of the patients accept regular intake of neuroleptic drugs. The question is whether an interval medication regimen as opposed to continuous medication can help to reduce drop outs in patients with critical attitudes towards long-term medication. In a 2-year prospective study, 122 patients were randomised to an interval and 164 to a continuous neuroleptic medication regimen. The drop out rates were 62.5% in the interval and 53.7% in the continuous medication group. Drop outs generally show more negative attitudes towards treatment. Patients with negative attitudes do not do better under interval medication. Moreover, this regimen even requires more cooperation and trust in terms of the necessity of medication on the part of the patient compared to the continuous medication regimen. Interval medication therefore is a strategy which can only be successful in highly cooperative, but not in treatment-reluctant patients.
The macroeconomic determinants of technology stock price volatility
Authors: Sadorsky Perry
Published: April 2003

Stock prices reflect the value of anticipated future profits of companies. Since business cycle conditions impact the future profitability of firms, expectations about the business cycle will affect the current value of firms. This paper uses daily and monthly data from July 1986 to December 2000 to investigate the macroeconomic determinants of US technology stock price conditional volatility. Technology share prices are measured using the Pacific Stock Exchange Technology 100 Index. One of the novel features of this paper is to incorporate a link between technology stock price movements and oil price movements. The empirical results indicate that the conditional volatilities of oil prices, the term premium, and the consumer price index each have a significant impact on the conditional volatility of technology stock prices. Conditional volatilities calculated using daily stock return data display more persistence than conditional volatilities calculated using monthly data. These results further our understanding of the interaction between oil prices and technology share prices and should be of use to investors, hedgers, managers, and policymakers.
Protein kinase CK2 phosphorylates Hsp105alpha at Ser509 and modulates its function
Authors: ISHIHARA Keiichi , YAMAGISHI Nobuyuki , HATAYAMA Takumi
Published: April 2003

The 105 kDa heat-shock protein (Hsp) Hsp105α is a mammalian stress protein that belongs to the HSP105/HSP110 family. We have shown previously that Hsp105α exists as non-phosphorylated and phosphorylated forms in vivo, and is phosphorylated by protein kinase CK2 (CK2) in vitro. In this study, to elucidate the role of phosphorylation of Hsp105α, we first analysed the site of phosphorylation of Hsp105α by CK2. Peptide mapping analysis of Hsp105α phosphorylated by CK2 and in vitro phosphorylation experiments using various deletion and substitution mutants of Hsp105α revealed that Hsp105α is phosphorylated at Ser509 in the β-sheet domain. Furthermore, Ser509 in Hsp105α was also phosphorylated in mammalian COS-7 cells, although other sites were phosphorylated as well. Next, we examined the effects of phosphorylation of Hsp105α on its functions using CK2-phosphorylated Hsp105α. Interestingly, Hsp105α suppressed 70 kDa heat-shock cognate protein (Hsc70)-mediated protein folding, whereas the phosphorylation of Hsp105α at Ser509 abolished the inhibitory activity of Hsp105α in vitro. In accordance with these findings, wild-type Hsp105α, which was thought to be phosphorylated in vivo, had no effect on Hsp70-mediated refolding of heat-denatured luciferase, whereas a non-phosphorylatable mutant of Hsp105α suppressed the Hsp70-mediated refolding of heat-denatured luciferase in mammalian cells. Thus it was suggested that CK2 phosphorylates Hsp105α at Ser509 and modulates the function of Hsp105α. The regulation of Hsp105α function by phosphorylation may play an important role in a variety of cellular events.
Interfacial kinetic analysis of the tumour suppressor phosphatase, PTEN: evidence for activation by anionic phospholipids
Authors: McCONNACHIE George , PASS Ian , WALKER Steven M. , DOWNES C. Peter
Published: April 2003

We investigated the kinetic behaviour and substrate specificity of PTEN (phosphatase and tensin homologue deleted on chromosome 10) using unilamellar vesicles containing substrate lipids in a background of phosphatidylcholine. PTEN displays the characteristics expected of an interfacial enzyme, since the rate of enzyme activity is dependent on the surface concentration of the substrate lipids used (mol fraction), as well as the bulk concentration. Surface-dilution analysis revealed the catalytic efficiency of PTEN for PtdIns(3,4,5)P3 to be 200-fold greater than for either PtdIns(3,4)P2 or PtdIns(3,5)P2, and 1000-fold greater than for PtdIns3P. The interfacial Km value of PTEN for PtdIns(3,4,5)P3 was very low, reflecting the small proportions of this lipid that are present in cellular membranes. The catalytic-centre activity (kcat) for PtdIns(3,4,5)P3 was at least 200-fold greater than that for the water-soluble substrate Ins(1,3,4,5)P4. The preference for lipid substrates may result from an interfacial activation of the enzyme, rather than processive catalysis of vesicular substrates. Moreover, both PtdIns(4,5)P2 and univalent salts stimulated the activity of PTEN for PtdIns(3,4,5)P3, but profoundly inhibited activity against Ins(1,3,4,5)P4. The stimulatory effect of PtdIns(4,5)P2 was greater in magnitude and more potent in comparison with other anionic phospholipid species. A mutation in the lipid-binding C2 domain (M-CBR3) that is biologically inactive did not alter overall catalytic efficiency in this model, but decreased the efficiency of the interfacial binding step, demonstrating its importance in the catalytic mechanism of PTEN.