bluuebunny/crossref_metadata_2025 huggingface dataset:
Positive and negative effects of nuclear receptors on transcription activation by AP‐1 of the human choline acetyltransferase proximal promoter
Authors: Schmitt M. , Bausero P. , Simoni P. , Queuche D. , Geoffroy V. , Marschal C. , Kempf J. , Quirin‐Stricker C.
Published: January 2005

We have examined the 5′‐flanking region (944 bp) of the human choline acetyltransferase (hChAT) gene for sequences that modulate its transcriptional activity and identified a sequence 5′‐TGACCA‐3′ which confers c‐Jun/c‐Fos (AP‐1) inducibility of homologous and heterologous promoters. Using transient transfections in neuroblastoma NE‐1–115 and COS‐1 cells, we show that ligand‐activated estrogen receptor (HEGo) represses the transcriptional activation by c‐Fos/c‐Jun. Testing HEGo mutants in transfection assays reveals that the ligand‐binding domain is crucial for this repression, whereas the N‐terminal (A/B) region and the DNA‐binding domain are not essential. Gel retardation assays show that the hChAT AP‐1 recognition sequence binds in vitro baculovirus‐produced c‐Jun/c‐Fos proteins. This binding is inhibited by addition of baculovirus‐produced HEGo. In contrast to HEGo, ligand‐activated glucocorticoid, androgen, and retinoic acid receptors (RARs) enhance the transcription activation induced by c‐Jun/c‐Fos. All three types of RARs—RARα, β, γ—and RXRα are able to stimulate AP‐1 activity on the proximal hChAT promoter. Several mechanism possibilities involving protein‐protein interaction are discussed to explain the phenomena. © 1995 Wiley‐Liss, Inc.
Chromosomal assignment of the human gene for the cancer‐associated retinopathy protein (recoverin) to chromosome 17p13.1
Authors: McGinnis J. F. , Austin B. , Klisak I. , Heinzmann C. , Kojis T. , Sparkes R. S. , Bateman J. B. , Lerious V.
Published: January 2005

The gene for the mouse recoverin protein (23 kDa photoreceptor‐specific protein, S‐modulin, or the Cancer‐Associated Retinopathy protein) was recently assigned to mouse chromosome 11, closely linked to trp53. In this paper, the human gene for recoverin was localized to human chromosome 17 by Southern analysis of restriction digests of the DNA from mouse/human somatic cell hybrids. Using a 7 kb subclone of the human recoverin gene, a positive fluorescence in situ hyridization signal was demonstrated near the terminus of the short arm of chromosome 17 at position p13.1. The mapping of recoverin to this region of human chromosome 17, which contains a number of cancer‐related loci, suggests a possible mechanism by which cancer‐associated retinopathy occurs in humans. © 1995 Wiley‐Liss, Inc.
Apoptosis occurs in the oligodendroglial lineage, and is prevented by basic fibroblast growth factor
Authors: Yasuda T. , Grinspan J. , Stern J. , Franceschini B. , Bannerman P. , Pleasure David
Published: January 2005

During the perinatal period, oligodendroglial precursor cells proliferate rapidly, then cease dividing and differentiate into oligodendroglia. Many of these newly formed oligodendroglia are destined to die. We now demonstrate that oligodendroglia generated in passaged cultures of rat forebrain oligodendroglial precursor cells after removal of basic fibroblast growth factor (basic FGF) from the medium often undergo internucleosomal DNA nicking and nuclear fragmentation, features characteristic of apoptosis. These alterations are rare in cultures maintained continuously in basic FGF. As in many other cellular lineages susceptible to apoptosis, these degenerative changes can be prevented by treatment with the endonuclease antagonist, aurintricarboxylic acid, or by inhibiting de novo RNA or protein synthesis. Supplementation of the basic FGF‐free medium with insulin, insulin‐like growth factor‐1, platelet‐derived growth factor, or ciliary neuronotrophic growth factor also diminishes DNA nicking. Both oligodendroglial differentiation and DNA nicking are induced in basic FGF‐treated cultures by inhibiting DNA synthesis with aphidicholin or excess thymidine, thus suggesting a close linkage between the anti‐apoptotic, anti‐differentiation, and mitogenic effects of basic FGF on the oligodendroglial lineage. © 1995 Wiley‐Liss, Inc.
Serotonin‐ and proton‐induced and modified ionic currents in frog sensory neurons
Authors: Philippi M. , Vyklický L. , Kuffler D. P. , Orkand Richard K.
Published: January 2005

Using the whole‐cell patch‐clamp technique, the effects of serotonin (5‐HT) and increased acidity to produce membrane currents and to modify high threshold voltage‐dependent calcium currents were studied in isolated dorsal root ganglion (DRG) cells of the frog maintained in short‐term culture. DRG cells were classified by morphology into two types: (1) cells with a large number of dark rusty brown granules, and (2) cells devoid of these granules or with few scattered pale granules. Fast application of 5‐HT (10–30 μM) induced a rapidly desensitizing inward current with a reversal potential at about 0 mV in 38 of 50 granule‐containing neurons (76%) which was never observed (0/35) in “clear” neurons. This current was blocked by 10 nM (+)‐tubocurarine. In addition, a small noninactivating outward current was also observed in most DRG neurons during 5‐HT superfusion. A sudden decrease of pH from 7.4 to 6 or 5.8 induced a fast inactivating inward current of 100–300 pA in 74% of the “clear” neurons and only 24% of the granule‐containing neurons. Small noninactivating membrane currents induced by lowering pH were observed in all neurons. Both 5‐HT and increased extracellular H+ reduced the magnitude of high threshold calcium currents in all DRG neurons. It is suggested that the 5‐HT receptors are expressed on a morphologically distinct population of neurons while the cells with channels responsible for the fast inactivating proton‐induced current cannot be related to any distinct morphological cell type. © 1995 Wiley‐Liss, Inc.
Nitric oxide‐sensitive protein ADP‐ribosylation is altered in rat diabetic neuropathy
Authors: Gorio Alfredo , Donadoni M. L. , Di Giulio A. M.
Published: January 2005

Endogenous ADP‐ribosylation of proteins was studied in retina crude extract, membrane and cytosolic fractions of control and diabetic rats. ADP‐ribosyl‐transferase activity is present in all cellular fractions, but protein ADP‐ribosylation is reduced in diabetic rat retina. At least 6 proteins are labelled in the crude extract fraction and a similar number in the membrane preparation of control animals. In these preparations from diabetic retina, only two bands were labelled, the 85 K and 36K for the crude extract, and the 97 K and 39 K for membranes. Labelling of 36 K and 39 K proteins was much less than in controls. In the cytosolic preparations of controls, two proteins of 85 K and 39 K are ADP‐ribosylated, while in diabetic rat retina cytosol, only the 85 K is labelled. Treatment of diabetic rats with insulin normalized plasma glucose levels and prevented the alterations of the extent of ADP‐ribosylation for the 38 K cytosolic, 39 K membrane and 36 K crude extracts proteins, but it failed to affect the other bands. These results suggest a hyperactivity of endogenous ADP‐ribosylases in diabetic rat retina, so that the protein sites for ADP‐ribosylation are no longer available. Since insulin treatment prevents the onset of neuropathy and of retinal G protein impairment (Abbracchio et al., J Neurosci Res 29:196–220, 1991) in diabetic rats and, in this study, normalizes ADP‐ribosylation of 39 K, 38 K and 36 K proteins, we suggest that the abnormal endogenous ADP‐ribosylation of these proteins might play a role in the onset of diabetic neuropathy. © 1995 Wiley‐Liss, Inc.
Recognition molecules myelin‐associated glycoprotein and tenascin‐C inhibit integrin‐mediated adhesion of neural cells to collagen
Authors: Bachmann M. , Conscience J.‐F. , Probstmeier R. , Carbonetto S. , Schachner Melitta
Published: January 2005

Because of the importance of collagens in mediating cell‐substrate interactions and the association of collagens with neural recognition molecules in the peripheral nervous system, the ability of neural recognition molecules to modify the substrate properties of collagens, in particular collagen type I, for cell adhesion was determined. Two cell lines, the N2A neuroblastoma and PC12 pheochromocytoma, were investigated for their capacity to adhere to different collagen types in the absence or presence of several neural recognition molecules. Adhesion of N2A or PC12 cells and membrane vesicles from PC12 cells to collagen type I was reduced when the collagen had been preincubated prior to its application as substrate with the extracellular domain of myelin‐associated glycoprotein (s‐MAG) or, as control, fibroblast tenascin‐C (F‐tenascin). In mixture with other collagen types, s‐MAG was only able to reduce the adhesiveness of collagen types III and V, but not of collagen types II and IV. F‐tenascin reduced the adhesiveness of all collagen types tested. In contrast to F‐tenascin, s‐MAG had to be present during fibrillogenesis to exert its effect, indicating that it must be coassembled into the collagen fibril to block the cell binding site. Cell adhesion to collagen type I was dependent on Mg2+ or Mn2+ and inhibited by a monoclonal antibody to the α1 integrin subunit. The combined observations indicate that s‐MAG and F‐tenascin interfere with cell binding, most probably by modifying the integrin binding site, and that the two molecules act by different mechanisms, both leading to reduction of adhesion. © 1995 Wiley‐Liss, Inc.
Characteristics of the K‐252a‐induced increase in calcium uptake in PC12 cells
Authors: Nikodijevic B. , Aschkenasy M. , Dickens G. , Lachance C. , Guroff Gordon
Published: January 2005

K‐252a treatment produced a 30–50% increase in the uptake of radioactive calcium by PC12 cells within 3–4 minutes. The increase in uptake was partially blocked by inhibitors of voltage‐operated calcium channels, such as nifedipine, but not by inhibitors of receptor‐operated calcium channels, such as nickel or suramin. Introduction of phosphatase 2A into the cells completely blocked the effect of K‐252a. Longterm treatment of the cells with either K‐252a or with nerve growth factor blocked the subsequent actions of either K‐252a or nerve growth factor on calcium uptake, but neither altered the subsequent action of the L‐channel agonist Bay K 8644 on calcium uptake. Calcium uptake was not stimulated by K‐252a in PC12nnr, cells that have little or no high‐affinity nerve growth factor receptors; cells expressing increased levels of high‐affinity nerve growth factor receptors showed a response to K‐252a comparable to that seen in parent PC12. The data suggest that the increased uptake of radioactive calcium produced by K‐252a is mediated by a mechanism very similar to that serving the increased calcium uptake produced by nerve growth factor. © 1995 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America
Colocalization of NGF and TSH‐like immunoreactivity in cultures of adult rat anterior pituitary cells
Authors: Burnham P. , Conner J. M. , Varon S.
Published: January 2005

Nerve growth factor (NGF) has been well‐characterized with respect to its role as a trophic agent for various peripheral nervous system (PNS) and central nervous system (CNS) neuronal populations. Recent evidence indicates that NGF may also play a functional role in endocrine systems, although investigations in this field are only beginning to define sites of action and molecular mechanisms involved in NGF endocrine interactions. A potential site for such an interaction to occur is within the pituitary. Previous investigations have demonstrated the presence of NGF and NGF receptors in the pituitary and our group has recently reported the presence of NGF‐like immunoreactivity exclusively within the thyrotrophic cells of the anterior pituitary of the adult rat. Since many questions regarding how NGF interacts in the anterior pituitary will be more efficiently addressed using an in vitro system, it was necessary to first determine if cultured adult anterior pituitary cells retain the NGF‐like staining and unique association of NGF with thyroid‐stimulating hormone‐producing cells seen in vivo. Results of the present investigation confirm that cultured anterior pituitary cells retain the characteristics previously observed in vivo and further demonstrate the stability of these cells and their specific NGF and pituitary hormone contents in culture for as long as 6 days. © 1995 Wiley‐iss, Inc.
Innervation of cutaneous structures in the mouse hind paw: A confocal microscopy immunohistochemical study
Authors: Navarro X. , Verdú E. , Wendelschafer‐Crabb G. , Kennedy W. R.
Published: January 2005

The normal innervation of structures in mouse foot pads was investigated with immunohistochemistry and confocal microscopy. Nerves were visualized by incubating Zamboni fixed, thick, frozen sections with antibodies to protein gene product 9.5 (PGP 9.5), vasoactive intestinal peptide, substance P, calcitonin gene‐related peptide, and protein zero. The antibodies were localized using cyanine 3.18 labeled anti‐rabbit gamma globulin. PGP 9.5 immunolocalization showed dense nerve bundles at the base of the foot pad with branches to larger blood vessels, sweat glands and epidermis. Sweat gland tubules were surrounded by numerous sudomotor axons; single fibers accompanied the sweat duct toward the skin's surface. Nerve bundles containing myelinated and unmyelinated axons ran through and around the centrally located sweat gland cluster to end in free nerve endings and Meissner's‐like corpuscles at the apex of the foot pad. Other bundles running parallel to the epidermis gave arcuate branches that supplied epidermis on the sides of the pads with a rich nerve network, principally with free nerve endings that often reached the most superficial cell layers of epidermis. Calcitonin gene‐related peptide‐immunoreactive (‐ir) nerves were distributed to dermis and epidermis in lower density than PGP 9.5‐ir fibers. Substance P‐ir fibers were less numerous; most terminated as free endings in deeper layers of epidermis. Vasoactive intestinal peptide‐ir nerves almost exclusively innervated sweat glands, ducts and blood vessels, but not epidermis. The mouse hind paw has potential to serve as a model system for investigations of functional and morphological changes that affect peripheral and au tonomic nerves under diverse experimental conditions. © 1995 Wiley‐Liss, Inc.
Intracellular routing of human amyloid protein precursor: Axonal delivery followed by transport to the dendrites
Authors: Simons M. , Ikonen E. , Tienari P. J. , Cid‐Arregui A. , Mönning U. , Beyreuther K. , Dotti C. G.
Published: January 2005

A characteristic neuropathological feature of Alzheimer's disease is the cerebral deposition of amyloid plaques. These deposits contain b̃A4 amyloid peptide, a cleavage product of the transmembrane protein amyloid protein precursor (APP). Despite numerous studies on the processing of the different APP isoforms in non‐neuronal cells, little is known about its sorting and transport in neurons cf the central nervous system (CNS). To analyze this question we expressed in cultured rat hippocampal neurons the human APP 695, tagged at its N‐terminus with the myc epitope, using the Semliki forest virus (SFV) expression system. APP was first delivered from the cell body to the axon and later appeared also in the dendrites. Inhibition of protein synthesis at the time of axonal expression did not block the late appearance of the protein in the dendrites. An antibody directed against the myc tag, bound to the cell surface at 4°C at the time of axonal APP expression, could be chased to the dendritic domain after subsequent incubation at 37°C. These results suggest that the newly synthesized APP, after initial axonal delivery, may be transported to the dendrites by a transcytotic mechanism. The routing of APP in polarized neurons is different from that of polarized epithelial cells, in which the protein is delivered basolaterally, arguing for neuronal specific sorting and processing mechanisms. © 1995 Wiley‐Liss, Inc.
Demonstration of interleukin‐3 receptor‐associated antigen in the central nervous system
Authors: Konishi Y. , Chui D.‐H. , Kunishita T. , Yamamura T. , Higashi Y. , Tabira T.
Published: January 2005

We previously reported that interleukin‐3 (IL‐3) acts as a neurotrophic factor for cholinergic neurons. However, it has not yet been determined whether the action is derived from the interaction of IL‐3 with IL‐3 receptors. As the first step to study IL‐3 receptors in the central nervous system, we examined the presence and localization of IL‐3 receptor‐associated antigen (IL‐3RAA) in mouse and rat brain. Immunohistochemically, IL‐3RAA, which is closely involved both in the IL‐3 binding to IL‐3 receptors and the tyrosine phosphorylation in the signal transduction for IL‐3 in hematopoietic cells, was demonstrated in neurons throughout the brain. This was confirmed in primary cultured neurons and neuronal cell lines by immunocytochemistry and flow cytometry. The staining intensity varied among regions and the most intense immunoreactivity for IL‐3RAA was found in large neurons in the magnocellular basal nuclei, pyramidal cells in the cerebral cortex, and neuronal cells in some nuclei of the brainstem. Not only cholinergic cell lines derived from the septal region but also other neuronal cell lines exhibited IL‐3RAA immunoreactivity by flow cytometry. Therefore, we conclude that IL‐3RAA is present in a wide variety of neurons in the brain including cholinergic neurons of the basal forebrain. Western blot analysis revealed that the candidates for IL‐3RAA are 145, 100, and 50 kDa proteins both in neuronal and IL‐3‐dependent cell lines. © 1995 Wiley‐Liss, Inc.
Second generation cholinesterase inhibitors: Effect of (L)‐huperzine‐A on cortical biogenic amines
Authors: Zhu X.‐D. , Giacobini E.
Published: January 2005

L‐Huperzine‐A (Hup‐A), a natural cholinesterase inhibitor (ChEI) derived from the Chinese herb Huperzia serrata, was administered systemically (i.p.) or locally through the microdialysis probe into the rat cortex. Systemic Hup‐A significantly increased acetylcholine (ACh) levels above baseline at doses of 0.1, 0.3, and 0.5 mg/kg; the increases were 54%, 129%, and 220%, respectively. Norepinephrine (NE) and dopamine (DA) levels were also increased 121% and 129% above baseline at 0.3 mg/kg, and 143% and 153% at 0.5 mg/kg. Peak cholinesterase (ChE) inhibition was 23% at 60 min with the 0.3 mg/kg dose. Huperzine‐A, perfused through the microdialysis probe, produced a maximal increase of ACh levels of 3090% and 7790% at concentrations of 5 and 50 μM. The ACh increase seen at both concentrations lasted at least 6 hr. At the 5‐μM dose, NE and DA were increased by 214% and 386%; at the 50‐μM dose, NE and DA were increased by 216% and 1141%. There were no changes of 5‐HT levels. With local administration (via the probe), both doses produced facialforelimb seizures that lasted throughout the perfusion. Our results show that Hup‐A is a potent inhibitor of ChE which penetrates into the brain and produces a dose‐dependent increase of ACh, NE, and DA in rat cortex. This effect is seen with both systemic and local intracerebral administration, suggesting cortical as well as subcortical effects of the drug. © 1995 Wiley‐Liss, Inc.
GABA‐induced motility of spinal neuroblasts develops along a ventrodorsal gradient and can be mimicked by agonists of GABAA and GABAB receptors
Authors: Behar T. N. , Schaffner A. E. , Tran H. T. , Barker J. L.
Published: January 2005

During embryogenesis, neuroblasts proliferate within germinal zones, then migrate to their final positions. Although many neurons migrate along radial glial fibers, evidence suggests that environmental factors, as yet unidentified, also influence neuroblast movement. In vivo, nerve growth factor (NGF) and ‐α‐aminobutyric acid (GABA) colocalize near target destinations of migratory neuroblasts. In vitro, embryonic spinal neurons migrate towards NGF and GABA (Behar et al.: J Neurosci 14:29‐38, 1994), implying that the molecules may act as chemoattractants in vivo. Here, we have used an in vitro assay of migration to show that migratory responses to these attractants develop along a ventrodorsal gradient that parallels terminal mitosis during cord development, and that GABA stimulates chemokinesis (motility without a gradient) via heterogeneous receptors involving separate signalling pathways. Both GABAA (muscimol) and GABAB (baclofen) agonists mimicked the effects of GABA in stimulating chemokinesis. Muscimol‐induced motility was only blocked by GABAA antagonists (bicuculline or picrotoxin), whereas migration to baclofen was blocked by antagonists of both GABAA and GABAB (2‐hydroxysaclofen) receptors. Migration to baclofen, but not muscimol, was abolished in the presence of 8‐bromo cAMP or pertussis toxin, indicating that the former, but not the latter, attractant may stimulate motility via Gi/Go GTP binding proteins, and that PKA may modulate migratory responses to baclofen. Migration to GABA was partially attenuated by each of the GABA receptor antagonists. These results lead us to conclude that the natural ligand stimulates neuroblast motility via heterogeneous receptors coupled to different signalling mechanisms. © 1995 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
AMPA receptors shape Ca2+ responses in cortical oligodendrocyte progenitors and CG‐4 cells
Authors: Holtzclaw L. A. , Gallo V. , Russell J. T.
Published: January 2005

Intracellular calcium signals triggered by glutamate receptor activation were studied in primary cortical oligodendrocyte lineage cells and in the oligodendrocyte cell line CG‐4. Glutamate, kainate, and AMPA (30‐300 μM) increased [Ca 2+]i in both types of cells at the stage of oligodendrocyte progenitors (O‐2A; GD3+) or pro‐oligodendroblasts (04+). The peak amplitude of Ca2+ responses to glutamate receptor agonists was significantly larger in cortical cells. In CG‐4 and in cortical cells, the majority (more than 90%) of bipolar GD3+ or multipolar 04+ cells responded to kamate. In all the cells analyzed, kainate was more efficacious than AMPA and glutamate. The percentage of bipolar or multipolar cells responding to glutamate was significantly lower in the CG‐4 cell line than in primary cultures. Cellular responses typical of metabotropic glutamate receptor activation were observed in 20% of the cortical O‐2A progenitors, but in none of the CG‐4 cells. The AMPA‐selective antagonist GYKI 52466 blocked kainate‐induced Ca2+ responses in cortical O‐2A cells. The selective AMPA receptor modulator cyclothiazide (30 μM) greatly potentiated the effects of AMPA (30‐100 μM) on [Ca 2+]i in cortical and CG‐4 cells. Our findings indicate that Ca2+ responses in cells of the oligodendrocyte lineage are primarily shaped by functional AMPA receptors. © 1995 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
Epidermal growth factor (EGF), transforming growth factor‐α (TGF‐α), and basic fibroblast growth factor (bFGF) differentially influence neural precursor cells of mouse embryonic mesencephalon
Authors: Santa‐Olalla J. , Covarrubias L.
Published: January 2005

Growth factors are key elements in the process of neural cell differentiation. We examined the effects of classical mitogens on neural precursor cells, by culturing mouse cells of the embryonic (13.5 days postcoitum) mesencephalon and treating them with epidermal growth factor (EGF), transforming growth factor‐β (TGF‐β), basic fibroblast growth factor (bFGF), nerve growth factor (NGF), and transforming growth factor‐β (TGF‐ β). Our initial results show that EGF, TGF‐α or bFGF, but not NGF or TGF‐β, induced general proliferation of the cultured cells, followed by formation of colonies. Combinations of these three growth factors suggest that most cells with the capacity to form colonies responded to EGF, TGF‐α, or bFGF. The number of colonies increased significantly when EGF, but not TGF‐α, was used in combination with bFGF. Furthermore, a population responding only to EGF + bFGF was detected in the dorsal mesencephalon. The colony‐forming activity of bFGF was dependent on insulin, but bFGF and insulin cooperation was indirect since we could not observe colony formation in subcultures of cells derived from colonies, even in the presence of insulin. Cells obtained from our colonies displayed neuronal and glial morphology and expressed markers of both neurons and astrocytes; nestin, a marker of neural precursor cells was also expressed in the majority of colonies. Growth factors also influenced neuronal maturation; the best neurite outgrowth was obtained from cells derived from bFGF‐induced colonies cultured in the presence of EGF + bFGF. These data indicate the existence of neural precursor cells in the embryonic mesencephalon that respond differentially to growth factors. © 1995 Wiley‐Liss, Inc.
Ligands for EPH‐related tyrosine kinase receptors are developmentally regulated in the CNS
Authors: Carpenter M. K. , Shilling H. , Vandenbos T. , Beckmann M. P. , Cerretti D. P. , Kott J. N. , Westrum L. E. , Davison B. L. , Fletcher F. A.
Published: January 2005

Elk is a member of the eph family of receptor‐like tyrosine kinases. Although its function is unknown, elk is postulated to play a role in nervous system development. Using Northern analysis, we examined the developmental regulation of RNAs encoding elk, and several ligands for the eph family of RTKs, the LERKs. Expression of elk, LERK‐1, and LERK‐2 RNAs is high in all regions examined in the embryonic and postnatal rat brain and decreases to low levels with age. One exception is the adult olfactory bulb which continues to express a moderate level of LERK‐2. In contrast, moderate LERK‐4 expression was limited to the developing hippocampus and cerebral cortex. These data indicate that elk and some of the LERKs may play a role in nervous system development, maintenance, and/or regeneration. © 1995 Wiley‐Liss, Inc.
Long‐term hippocampal slices: A model system for investigating synaptic mechanisms and pathologic processes
Authors: Bahr B. A.
Published: January 2005

Organotypic cultures provide a unique strategy with which to examine many aspects of brain physiology and pathology. Long‐term slice cultures from the hippocampus, a region involved in memory encoding and one that exhibits early degeneration in Alzheimer's disease and ischemia, are particularly valuable in this regard due to their expression of synaptic plasticity mechanisms (e.g., long‐term potentiation) and responsiveness to pathological insults (e.g., excitotoxicity). Long‐term slices can be prepared from hippocampi at the second or third postnatal week of development and thus incorporate a number of relatively mature features; further signs of maturation and the preservation of adult‐like characteristics occur over succeeding weeks. The stability of the cultured slice renders it an appropriate model for studying (1) prolonged regulation/stabilization events linked to synaptogenesis and certain forms of plasticity, (2) temporal patterns of cellular atrophy associated with pathogenic conditions such as ischemia and epilepsia, and (3) slow processes associated with aging and agerelated pathologies. © 1995 Wiley‐Liss, Inc.
Immunolabeling of the Na+/C1− dependent “orphan” transporter Rxt1 in the rat central nervous system
Authors: Masson J. , Langlois X. , Lanfumey L. , Gérard C. , Aïdouni Z. , Giros B. , Hamon M. , El Mestikawy S.
Published: January 2005

Previous studies have shown that the mRNA encoding the Na+/Cr− dependent “orphan” transporter Rxt1 is expressed exclusively in the central nervous system (CNS). In the present study, specific antibodies were raised in rabbits for the detailed mapping of this transporter in the rat. The C‐terminal part of Rxtl was fused with glutathione‐S‐transferase (Rxtlct GST) and the resulting fusion protein was used as antigen. The specificity of the antiserum toward Rxtl was confirmed by immunofluorescent, Western blot, and immunoautoradiographic experiments. In cerebral cortex membranes, Rxtl‐like material recognized by the antiserum is a glycosylated protein of 97‐116 kDa. This protein was the most abundant in the caudate‐putamen, followed, in decreasing order, by the cerebral cortex ≈︁ hippocampus > cerebellum > brainstem > spinal cord. In contrast, no immunoreactive material could be detected in peripheral tissues (tongue, thymus, heart, lung, spleen, kidney, adrenals, liver, skeletal muscle, intestine, testis). Immunoautoradiographic labeling with affinity‐purified anti‐Rxtlet‐GST antibodies showed high levels of Rxtl‐like material in the olfactory bulb, cerebral cortex, striatal complex, hippocampal formation, superior layer of the anterior colliculus, cortex, and deep nuclei in the, cerebellum. The regional distribution of Rxtl‐like material generally matched that of GABAergic and glutamatergic projections in agreement with previous in situ hybridization data. © 1995 Wiley‐Liss, Inc.
Immunolocalization of GLUT1 and GLUT3 glucose transporters in primary cultured neurons and glia
Authors: Maher F.
Published: January 2005

Immunofluorescence analysis was used to study the cellular localization of glucose transporters 1 and 3 (GLUT1 and GLUT3) in primary rat neuronal and glial cultures. In primary cultured cerebellar granule neurons and cortical neurons, GLUT3 was detected in a pattern consistent with a generalized cell surface distribution. GLUT3 distribution corresponded most closely with the neural cell adhesion molecule (NCAM), and showed overlapping but distinct distributions compared to synaptophysin, microtubule‐associated protein 2 (MAP2), neurofilament protein, and growth‐associated protein (GAP43). Culture of neurons in the presence of glia did not alter the cellular localization of GLUT3. GLUT1 was detectable in primary cerebellar granule neurons both at the cell surface and in the cytoplasm, and appeared decreased in neurons cocultured with glia. GLUT1, but not GLUT3, was detected in glial fibrillary acidic protein (GFAP)‐positive astrocytes present in mixed neuronal‐glial cultures derived from cerebellum and cerebral cortex, as well as in cortical astrocyte cultures. GLUT1, but not GLUT3, was also detected in microglia and oligodendrocytes present in these cultures. This study indicates a generalized cell surface expression of the glucose transporters expressed in neurons and glia, rather than selective targeting to different cellular domains or subcellular locations. © 1995 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
Developing oligodendroglia express mRNA for insulin‐like growth factor‐I, a regulator of oligodendrocyte development
Authors: Shinar Y. , McMorris F. A.
Published: January 2005

Insulin‐like growth factors IGF‐I and IGF‐II are potent inducers of oligodendrocyte development. Because IGF‐I is produced, in some cases, by the same cells that respond to it (autocrine/paracrine action), we examined the possibility that IGF‐I is expressed by developing oligodendroglial cells. We employed a sensitive method, reverse transcriptase‐polymerase chain reaction (RT‐PCR), to detect IGF‐I mRNA in purified populations of oligodendroglial cells isolated from rat brain during the period of oligodendrocyte development. Cells were purified by fluorescence activated cell sorting (FACS), using antibodies to the cell surface antigenic markers 04 and galactocerebroside (GC). RNA was isolated from the sorted cells, reverse‐transcribed, and PCR‐amplified, using a strategy that recognizes IGF‐I mRNA but not DNA. The amplified band was identified as IGF‐I by size, hybridization to an IGF‐I‐specific antisense probe, and restriction analysis. IGF‐I mRNA was detected in O4‐positive/ GC‐negative oligodendrocyte precursors and, more weakly, in GC‐positive oligodendrocytes. IGF‐I mRNA could be detected reproducibly in RNA extracted from 100‐cell samples of O4‐positive cells, making it unlikely that the mRNA was derived from contaminants in the FACS‐sorted cell populations. We conclude that IGF‐I is expressed by developing oligodendroglia. Autocrine expression of IGF‐I by developing oligodendroglial cells suggests that oligodendrocyte development is, in part, autoregulatory. © 1995 Wiley‐Liss, Inc.
Acetylcholinesterase expression in NTera 2 human neuronal cells: A model for developmental expression in the nervous system
Authors: Llanes C. , Collman R. G. , Hrin R. , Kolson D. L.
Published: January 2005

Acetylcholinesterase (AChE; EC 3.1.1.7) is expressed in the central nervous system in multiple molecular forms that may subserve multiple functions and may be selectively lost in neurodegenerative illnesses such as Alzheimer's disease. AChE expression has been studied in primary cultures of developing vertebrate nervous system, but investigation has been limited by the lack of a suitable human CNS surrogate cell model system for in vitro studies and the inability of primary brain cultures to provide large numbers of pure neurons. To develop an in vitro model for studies of neuronal AChE expression and function, we utilized a neuronally committed human teratocarcinoma cell line, NTera 2, that can be induced to differentiate to a post‐mitotic CNS neuronal phenotype. We found that NTera 2 cells express multiple molecular forms of AChE that are similar to CNS‐derived AChE isoforms in velocity sedimentation profile, anion exchange elution profile, and sensitivity to inhibitors. At least two forms of ACNE are expressed (G1 and G4), similar to human and rodent brain, and induction of NTera 2 cell differentiation results in an increased G4/G1 ratio, which is characteristic of mature neurons. As in primary CNS neurons, AChE is present in NTera 2 cells in both the cytosolic fraction and in the outer membrane, and is also released in a soluble form. These observations indicate that NTera 2 cells provide a useful human model system for studies of expression of cell‐associated and soluble cell‐free AChE in developing and mature human neurons and for elucidating the potential role(s) of acetylcholinesterase metabolism in both normal development and neurodegenerative disease states. ©1995 Wiley‐Liss, Inc.
Multiple tyrosine hydroxylase transcripts and immunoreactive forms in the rat: Differential expression in the anterior pituitary and adrenal gland
Authors: Schussler N. , Boularand S. , Li J. Y. , Peillon F. , Mallet J. , Biguet N. Faucon
Published: January 2005

Several regulatory neurotactors, classically associated with the hypothalamus, may be synthesized in the anterior pituitary (AP). Dopamine (DA) is the main prolactin‐inhibiting factor. Its de novo synthesis in the normal AP has not been proved, although the TH transcript has been previously demonstrated by RT/PCR in the AP. We investigated tyrosine hydroxylase (TH) gene expression at both the protein and mRNA levels in the AP of normal random cycling female rats and in a catecholaminergic tissue, the adrenal gland (AG). The Western blot analysis of AP homogenates revealed two immunoreactive forms of TH in the AP, both differing from the TH present in the AG. RT/PCR products from AP and AG mRNA were subcloned and sequenced. In addition to the full‐length form, we identified two TH transcripts generated by alternative splicing either involving the use of a new alternate splice‐donor site within exon 2 or skipping exon 11. The form lacking exon 11 was not isolated from the AG. In the AP, all three forms were present. Although the AP contained the full‐length TH mRNA, the expected size protein was not detected. Thus, there is alternative splicing of the TH primary transcript, and putative additional poisttranslational regulation may yield TH proteins with no enzymatic activity, at least in non‐catecholaminergic tissues. ©1995 Wiley‐Liss, Inc.
Immediate early gene c‐fos regulates the synthesis of phospholipids but not of gangliosides
Authors: Guido M. E. , de Arriba Zerpa G. A. , Bussolino D. F. , Caputto B. L.
Published: January 2005

Retinal ganglion cells isolated from chicks that in vivo were exposed to light have a higher phospholipid labeling capacity than those obtained from animals in the dark. Actinomycin D or a mixture of protein synthesis inhibitors or of antisense oligonucleotides to c fos plus c‐jun injected intraocularly 1 hr prior to the stimulation period, abolished the light‐dark differences for phospholipids but not for gangliosides. Light stimulation induced the formation (and/or stabilization) of c fos mRNA and of the protein c‐Fos, indicating that immediate early gene induction, and consequently the synthesis of the protein(s) encoded, is essential to increase the synthesis of phospholipids but not of gangliosides. These results suggest a novel mechanism by which immediate early genes engram neural cells, modifying specifically the metabolism of cell constituents producing long‐lasting changes in the cells. © 1996 Wiley‐Liss, Inc.
Changes in glycoalkaloid and nitrate contents in potatoes during French fries processing
Authors: Rytel Elžbieta , Gołubowska Gražyna , Lisińska Gražyna , Pȩksa Anna , Aniołowski Karol
Published: January 2005

The purpose of this investigation was to determine the influence of various stages of French fries processing on the contents of glycoalkaloids and nitrates in potatoes. The material for the study comprised samples of two potato varieties, Santana and Innowator, collected from nine stages of a French fries production line. Based on the results of the research carried out, it was found that the processes applied during French fries production had a significant influence on the decrease in glycoalkaloid (chaconine and solanine) and nitrate contents in both intermediate products and the final product in comparison with the raw material. The highest amounts of glycoalkaloids and nitrates were removed during peeling, blanching and frying. In the processed potatoes the ratio of chaconine to solanine decreased. French fries ready for consumption contained only 3–8% of the glycoalkaloids and 5–6% of the nitrates found in the raw material. Copyright © 2004 Society of Chemical Industry
Abdominal Compartment Syndrome After Liver Transplantation
Authors: Handschin Alexander E. , Weber Markus , Renner Eberhard , Clavien Pierre-Alain
Published: January 2005

The abdominal compartment syndrome is a well-known complication after abdominal trauma and is increasingly recognized as a potential risk factor for renal failure and mortality after adult orthotopic liver transplantation (OLT). We present a case report of a young patient who presented with acute liver failure complicated by an acute pancreatitis. The patient developed an acute abdominal compartment syndrome after OLT. Transurethral measurement of intraabdominal pressure indicated an abdominal compartment syndrome associated with impaired abdominal vascular perfusion, including liver perfusion. Renal insufficiency was immediately reversed after decompressive bedside laparotomy. The abdominal compartment syndrome is a potential source of posttransplant renal insufficiency and liver necrosis in OLT. It remains, however, a rarely described complication after liver transplantation, despite the presence of significant factors that contribute to elevated intraabdominal pressure.
Corticosteroid-Free Immunosuppression With Tacrolimus Following Induction With Daclizumab: a Large Randomized Clinical Study
Authors: Boillot Olivier , Mayer David A. , Boudjema Karim , Salizzoni Mauro , Gridelli Bruno , Filipponi Franco , Trunecka Pavel , Krawczyk Marek , Clavien Pierre-Alain , Ducerf Christian , Margarit Carlos , Margreiter Raimund , Pallardo José Mir , Hoeckerstedt Krister , Pageaux George-Phillipe
Published: January 2005

This open, randomized (1:1), multicenter, 3-month study compared a dual tacrolimus plus steroids (Tac / steroids) regimen with a steroid-free immunosuppressive regimen of tacrolimus following daclizumab induction therapy (Tac / Dac) in adult liver transplant recipients. The full analysis set comprised 347 patients in the Tac / steroids group and 351 in the Tac / Dac group. Mean tacrolimus dose during month 3 was 0.11 mg/kg/day in both groups; mean whole-blood trough levels during month 3 were 10.9 ng/mL (Tac / steroids) and 10.6 ng/mL (Tac / Dac). The incidence of biopsy-confirmed acute rejection that required treatment was similar in both groups: 26.5% in the Tac / steroids group and 25.4% in the Tac / Dac group (

P

= .727). However, the incidence of biopsy-confirmed corticosteroid-resistant acute rejection was higher in the Tac / steroids group than in the Tac / Dac group (6.3 vs. 2.8%;

P

= .027). Kaplan-Meier estimates of graft survival (92.2 vs. 90.5%) and patient survival (94.5 vs. 93.7%) were similar in both groups. While also the overall adverse event profiles were similar, the incidences of diabetes mellitus (15.3 vs. 5.7%, respectively;

P

< .001) and cytomegalovirus infection (11.5 vs. 5.1%, respectively;

P

= .002) were higher in the Tac / steroids group compared with the Tac / Dac group. Mean cholesterol levels increased by 16% in the Tac / steroids group, but were unchanged in the Tac / Dac group during the study. In conclusion, tacrolimus monotherapy following daclizumab induction is an effective and safe regimen, with an advantage over concomitant steroid-maintenance therapy in terms of a lower incidence of diabetes and viral infection, and a lower incidence of steroid-resistant acute rejection.
Korrosion an Dichtflächen von Flanschverbindungen
Authors: Fischer Christian , Zitter Herbert
Published: December 2004

Der überwiegende Anteil der Korrosionsfälle an Dichtflächen beruht auf dem Flüssigkeitstransport durch die Poren der Dichtung. Die eingedrungene Lösung kann durch Diffusion und Auflösung der Dichtung an den Stahl gelangen und sich dort durch Abdampfen nach außen konzentrieren. Dies führt bei Abwesenheit von passivierenden Stoffen zu einem charakteristischen örtlichen Angriff auf die Dichtflächen. Daneben können gleichzeitig Lochkorrosion und Spannungsrißkorrosion als Sekundärerscheinungen auftreten. Die beschriebene Art des Angriffes kann durch porenfreie Dichtungen aus Kunststoff mit Erfolg verhindert werden. Die ebenfalls an Dichtungen beobachtete Spaltkorrosion dagegen ist meist auf eine unsachgemäße Konstruktion der Flansche oder auf schlecht eingebaute Dichtungen zurückzuführen.
Über die mechanischen Eigenschaften metallischer Werkstoffe bei tiefen Temperaturen
Authors: Hickel F.
Published: December 2004

Die Kenntnisse des Verhaltens metallischer Werkstoffe bei mechanischen Beanspruchungen bei tiefen Temperaturen gewinnt zunehmend an Bedeutung. Vor allem in der Kältetechnik, z. B. im Zusammenhang mit der Verflüssigung, Lagerung und Beförderurng von Gasen ist man bestrebt, mit möglichst billigen Werkstoffen, die auch unter ungünstigen Beanspruchungsbedingungen bis zu tiefen Temperaturen ihre Zähigkeitseigenschaften behalten, auszukommen. Bei tiefen Temperaturen sind sowohl die den Formänderungswiderstand sowie die die Formänderungsfähigkeit kennzeichnenden Größen von der Kristallstruktur abhängig. Die Verwendung unlegierter Baustähle konnte durch besondere metallurgische Behandlung der Schmelzen, z. B. durch Verminderung der gelösten Gasmengen sehr erweitert werden. An den Verwendungsbereich dieser Stäuhle, der je nach Anstrengung und Gefährlichkeit eventueller Bruchauswirkungen bis −50° C reicht, schließt sich der der vergüteten, legierten Stähle für Temperaturen bis −120° C; für noch tiefere Temperaturen schließt sich das Gebiet der Anwendung austenitischer Stähle an. Gegossene Eisen‐Kohlenstoff‐Legierungen sind, wie z. B. Stahlguß, wegen des anisotropen Verhaltens besonders bei tiefen Temperaturen bruchempfindlicher als warmverarbeitete Werkstoffe, wenn nicht durch entsprechende Glühbehandlungen die Ungleichmäßigeiten in der Beanspruchungsfähigkeit des Kleingefüges weitgehend behoben werden Während besonders unlegiertes Gußeisen bei tiefen Temperaturen Zähigkeitsverminderungen bei plötzlich wirkenden Beanspruchungen aufweist, sind sowohl Kupfer‐, als auch Aluminium‐Legierungen bis zu tiefsten Temperaturen sehr schlagzähe.
Der unterschiedliche Ätzangriff von Flußsäure und Salzsäure auf Aluminium
Authors: Möhlhäußer M.
Published: December 2004

Die Erscheinung, daß bei der Ätzung von Aluminium mit Salzsäure eine starke Oberflächenaufrauhung, bei der Verwendung von Flußsäure dagegen nur eine flache Metallabtragung erfolgt, wird durch zwei verschiedene Reaktionsmechanismen erklärt:

In Salzsäure dringen infolge der anodischen Polarisation der Aluminiumoberfläche die Chlorionen an schwachen Stellen der Oxidschicht ein, wobei sich die Wasserstoffionen an kathodischen Stellen (z. B. Fremdkristallen in der Aluminiumoberfläche) entladen.

In Flußs'säure dagegen wird über die gesamte Oberfläche hinweg die Oxidschicht von den Wasserstoffen gleichmäßig durchdrungen, doch erfolgt dann der Austausch ihrer Ladungen ohne die Vermittlung kathodischer Stellen.

Diese unterschiedlichen Reaktionsmechanismen erklärt man mit dem geringeren Eindringungsvermögen des Fluorions in die Oxidschicht. Dabei wird angenommen, daß das Fluorion entweder wie die undissoziierte Flußsäure polymer vorliegt oder daß es eine größere Hydrathülle als das Chlorion besitzt.

Die verschiedenen Reaktionsmechanismen werden nachgewiesen.
Haftfestigkeit an Grenzflächen
Authors: Neumann A. W.
Published: December 2004

Ausgehend von der Annahme, daß die Haftfestigkeit zwischen zwei Phasen ‐z.B. Anstrichfilm und Substrat‐ eine Funktion der Grenzflächenspannung an der betreffenden Phasengrenzfläche ist, werden verschiedene Systeme zum Oberflächenschutz überprüft. Zunächst wird die Annahme bestätigt in Versuchen über das Haftvermögen von PTFE‐Pulver an verschiedenen Kunststoffen. Außerdem wird gefunden, daß die Zug‐ und Schälfestigkeit verklebter Kunststoffe mit zunehmender Grenzflächenspannung zwischen Kunststoff und ausgehärtetem Klebstoff rasch abnehmen. In Analogie dazu wurde festgestellt, daß die gleiche Beziehung auch für die Verschmutzbarkeit von Anstrichfilmen gilt: mit abnehmender Grenzflächenspannung, d.h. zunehmender Benetzbarkeit, nimmt die Verschmutzungsanfälligkeit zu. In der Praxis ist man gezwungen, einen Kompromiß zu suchen, um einerseits austeichende Haftfestigkeit des Lackfilms und andererseits geringe Verchmutzungsanfälligkeit zu erhalten.
Einfluß des entstehenden Rostes auf den Verlauf der atmosphärischen Korrosion von Stahl
Authors: Bartoň K. , Marek V.
Published: December 2004

Ein Vergleich des Rostungsverlaufs bei kontinuierlicher Rostbildung einerseits mit den während dieser Zeit an analogen Proben in bestimmten Zeitabständen gefundenen und kumulierten Werten andererseits zeigt, daß es einerseits einen kritischen Wert der SO2‐Konzentration gibt und daß andererseits der vorhandene Rost in der Lage ist, gewisse SO2‐Mengen von der Oberfläche fernzuhalten. Diese letzte Wirkung erklärt die zeitliche Abnahme der Rostungsgeschwindigkeit bis zu stationären Werten, und auch die Tatsache, daß die stationären Bedingungen in reiner Atmosphäre später erreicht werden als in Industrieatmosphäre.
CVD‐Silizium als Korrosionsschutz für die Beschaufelung von stationären Gasturbinen
Authors: Felix P. , Erdös E.
Published: December 2004

Zur Erhöhung der Korrosionsbeständigkeit von hochwarmfesten Nickellegierungen, die als Schaufelmaterialien für stationäre Gasturbinen Verwendung finden, wurden diese Materialien nach einem CVD‐Verfahren (Chemical Vapor Deposition) mit Silizium beschichtet. Mit Hilfe von Mikrosonden‐ und Röntgenuntersuchungen wurden die gebildeten Silizide identifiziert.

Beschichtete Proben wurden einer Reihe von spezifisch auf den Einsatz in stationären Gasturbinen ausgerichteten Prüfverfahren ausgesetzt. Dabei zeigte sich, daß Silizidschichten auf Nickellegierungen außerordentlich beständig gegen Hochtemperaturkorrosion sind und eine wesentliche Erhöhung der Standzeiten von silizierten Gasturbinenschaufeln erwarten lassen.