bluuebunny/crossref_metadata_2025 huggingface dataset:
High signal peripancreatic fat on fat‐suppressed spoiled gradient echo imaging in acute pancreatitis: Preliminary evaluation of the prognostic significance
Authors: Martin Diego R. , Karabulut Nevzat , Yang Ming , McFadden David W.
Published: June 2003

Purpose

To evaluate peripancreatic signal changes on fat‐suppressed T1‐weighted spoiled gradient echo images associated with acute pancreatitis and investigate potential utility in regards to relationship to clinical outcome.

Materials and Methods

The abdominal MR images in 31 patients with acute pancreatitis were reviewed, and evaluated for the presence of elevated signal intensity within the peripancreatic fat on fat‐suppressed T1‐weighted spoiled gradient echo images; the degree of signal changes was graded as mild, moderate, or severe.

Results

Ten of 31 patients demonstrated abnormal high signal intensity in the peripancreatic fat on fat‐suppressed T1‐weighted images. The degree of signal change was mild in three patients, moderate in one, and severe in six patients. All six patients with severe elevated peripancreatic soft tissue signal died within seven to 68 days (mean, 47 days) of their admission. All 21 patients without elevated peripancreatic fat signal survived without any complications. The correlation between the presence and severity of elevated peripancreatic MR signal and patient outcome was significant (P < 0.05).

Conclusion

Elevated peripancreatic signal on fat‐suppressed T1‐weighted images is associated progressively with poor outcome in patients with acute pancreatitis, and may represent a simplified method for prognostic cross‐sectional imaging. J. Magn. Reson. Imaging 2003;18:49–58. © 2003 Wiley‐Liss, Inc.
Spatial excitation using variable‐density spiral trajectories
Authors: Schröder Christoph , Börnert Peter , Aldefeld Bernd
Published: June 2003

Purpose

To examine the usefulness of variable‐density k‐space trajectories for the design of multi‐dimensional spatially selective RF pulses.

Materials and Methods

Experimental phantom and in vivo studies were performed and confirmed by simulations. Two‐dimensional spatially selective magnetization patterns were excited using variable‐density spiral trajectories and analyzed with respect to the signal excitation outside the excitation field of view (FOX).

Results

By using variable‐density trajectories, signal excitation outside the FOX was drastically reduced compared to trajectories with a uniform density, while maintaining fairly short pulse durations.

Conclusion

A main advantage of the method is that unwanted signal excitation outside the nominal FOX can be reduced without significantly increasing the duration of the RF excitation pulse. The variable‐density approach is useful for all applications that require a well‐defined spatial excitation profile, e.g., to perform imaging in a reduced field of view (FOV), for spatial saturation pulses, for curved slice imaging or in MR spectroscopy. J. Magn. Reson. Imaging 2003;18:136–141. © 2003 Wiley‐Liss, Inc.
Role and expression of thrombin receptor PAR‐1 in muscle cells and neuromuscular junctions during the synapse elimination period in the neonatal rat
Authors: Lanuza María A. , Garcia Neus , González Carmen M. , Santafé Manel M. , Nelson Phillip G. , Tomas Josep
Published: June 2003

A role for thrombin and its receptor (ThR) during mammalian skeletal muscle cell differentiation and neuromuscular junction (NMJ) formation has been suggested. Previously, we found that the synapse elimination process in the neonatal rat muscle was accelerated by thrombin and blocked by hirudin, its specific inhibitor (Lanuza et al. [2001] J. Neurosci. Res. 63:330–340). To test whether this process resulted from a signal transduction cascade initiated by activation of ThR, in particular PAR‐1, we applied to the levator auris longus (LAL) muscle of newborn rats two synthetic peptides (SFLL and FSLL). SFLL is a potent specific agonist for activation of PAR‐1, whereas FSLL is an inactive peptide. We have demonstrated that the activation of PAR‐1 by SFLL produced acceleration of the presynaptic loss of connections and the postsynaptic maturation of NMJs. Moreover, Western blot analysis showed that PAR‐1 was present in the skeletal muscle, and by immunohistochemistry we detected PAR‐1 in muscle fibers concentrated in the synaptic area but also in satellite cells. Several lines of evidence suggested that PAR‐1 is localized in the postsynaptic membrane: PAR‐1 immunofluorescence was concentrated at denervated synaptic sites and was present in the myotube membrane in vitro in the absence of neurons and in dissociated single muscle fibers from which nerve terminals and Schwann cells had been removed. Taken together, these results indicate that thrombin mediates certain stages of activity‐dependent synapse elimination in the skeletal muscle and does so through its action on the thrombin receptor PAR‐1 localized, at least in part, on the postsynaptic membrane. © 2003 Wiley‐Liss, Inc.
Motor cortical control of cardiovascular bulbar neurones projecting to spinal autonomic areas
Authors: Viltart Odile , Mullier Olivia , Bernet François , Poulain Pierre , Ba‐M'Hamed Saadia , Sequeira Henrique
Published: June 2003

There is evidence that the motor cortex is involved in cardiovascular adjustments associated with somatic motor activity, as it has functional connections with the ventrolateral medulla, a brainstem region critically involved in the control of blood pressure and the regulation of plasma catecholamine levels. The ventrolateral medulla sends projections to the spinal intermediolateral nucleus, where preganglionic neurones controlling heart and blood vessels (T2 segment) and adrenal medulla (T8 segment) are found. The aim of the present study was to determine whether electrical stimulation of the rat motor cortex induces cardiovascular responses and Fos expression in ventrolateral medulla neurones projecting to the T2 and T8 segments. After a set of experiments designed to record cardiovascular parameters (blood pressure and plasma catecholamine levels), injections of retrograde tracer (Fluorogold) were performed in the intermediolateral nucleus of two groups of rats, at the T2 or at the T8 segmental levels. Five days later, the motor cortex was stimulated in order to induce Fos expression in the ventrolateral medulla. Stimulation of the motor cortex induced: (1) hypotension and a significant decrease in plasma noradrenaline levels, and (2) a significant increase in the number of the double‐labelled neurones in the rostral ventrolateral medulla projecting to T2. These data demonstrate that cardiovascular adjustments, preparatory to, or concomitant with, motor activity may be initiated in the motor cortex and transmitted to cardiac and vasomotor spinal preganglionic neurones, via the ventrolateral medulla. © 2003 Wiley‐Liss, Inc.
Early induction of secondary injury factors causing activation of calpain and mitochondria‐mediated neuronal apoptosis following spinal cord injury in rats
Authors: Wingrave J. Michael , Schaecher Kurt E. , Sribnick Eric A. , Wilford Gloria G. , Ray Swapan K. , Hazen‐Martin Debra J. , Hogan Edward L. , Banik Naren L.
Published: June 2003

To investigate a potential relationship between calpain and mitochondrial damage in spinal cord injury (SCI), a 40 gram‐centimeter force (g‐cm) injury was induced in rats by a weight‐drop method and allowed to progress for 4 hr. One‐centimeter segments of spinal cord tissue representing the adjacent rostral, lesion, and adjacent caudal areas were then removed for various analyses. Calcium green 2‐AM staining of the lesion and penumbra sections showed an increase in intracellular free calcium (Ca2+) levels following injury, compared with corresponding tissue sections from sham‐operated (control) animals. Western blot analysis showed increased calpain expression and activity in the lesion and penumbra segments following SCI. Double‐immunofluorescent labeling indicated that increased calpain expression occurred in neurons in injured segments. Western blot analysis also showed an increased Bax:Bcl‐2 ratio, indicating the induction of the mitochondria‐mediated cell death pathway in the lesion and penumbra. The morphology of mitochondria was altered in lesion and penumbra following SCI: mostly hydropic change (swelling) in the lesion, with the penumbra shrunken or normal. At 4 hr after induction of injury, a substantial amount of cytochrome c had been released into the cytoplasm, suggesting a trigger for apoptosis through caspase 3 activation. Neuronal death after 4 hr of injury was detected by a combined TUNEL and double‐immunofluoresence assay in the lesion and penumbra sections of injured cord, compared with sham controls. These results suggest that an early induction of secondary factors is involved in the pathogenesis of SCI. The increased Ca2+ levels could activate calpain and mediate mitochondrial damage leading to neuronal death in lesion and penumbra following injury. Thus, secondary injury processes mediating cell death are induced as early as 4 hr after the injury, and calpain and caspase inhibitors may provide neuroprotection. © 2003 Wiley‐Liss, Inc.
Gene expression profiling of ciliary neurotrophic factor‐overexpressing rat striatal progenitor cells (ST14A) indicates improved stress response during the early stage of differentiation
Authors: Böttcher Tobias , Mix Eilhard , Koczan Dirk , Bauer Peter , Pahnke Jens , Peters Sabine , Weinelt Sabine , Knoblich Rupert , Strauss Ulf , Cattaneo Elena , Thiesen Hans‐Jürgen , Rolfs Arndt
Published: June 2003

Neuronal progenitor cells delivering neurotrophic factors are a promising therapeutic tool for treatment of neurodegenerative diseases. Although several promising results have come from studies in different animal models, detailed knowledge of the action of neurotrophic factors in the CNS is still lacking. A clonally derived, immortalized rat striatal cell line (ST14A) expressing ciliary neurotrophic factor (CNTF) offers a stable and controlled background with which to analyze CNTF actions on the transcriptional level in CNS progenitor cells. To identify early transcriptional changes induced by CNTF expression, we transfected the CNTF gene into ST14A cells, which differentiate at the nonpermissive temperature of 39°C via suppression of the immortalizing SV40 large T antigen. This shows a CNTF‐dependent hypoxic/ischemic stress response during the earliest stage of differentiation, with expression of specific transcripts and evidence of translational repression leading to decreased protein synthesis in the transfected cells. This process is mediated by the Ras/MAP kinase pathway and is accompanied by impaired proliferation and metabolism as well as signs of neuronal differentiation. The stress‐like response in the early stage of differentiation improves the ability of the transfected cells to respond to and cope with a stressful environment in vivo. The present data indicate higher viability, longer life, and greater differentiation capacity of CNTF‐ST14A cells if they are used for transplantation. We conclude that the stress‐like response during the early stage of differentiation improves the ability of the CNTF‐ST14A cells to respond and adapt to a stressful environment, which renders them useful candidate cells for in vivo trials of treatment for neurodegenerative diseases in animal models, e.g., of Huntington's disease. © 2003 Wiley‐Liss, Inc.
Altered astrocyte calcium homeostasis and proliferation in theTs65Dn mouse, a model of Down syndrome
Authors: Bambrick Linda L. , Yarowsky Paul J. , Krueger Bruce K.
Published: June 2003

Genes from the Down syndrome (DS) critical region of human chromosome 21, which contribute to the pathology of DS, are also found on mouse chromosome 16. Several animal models of DS with triplication of genes from the DS critical region have been generated, including mouse trisomy 16 (Ts16) and a partial trisomic mouse, Ts65Dn. Using computer‐assisted imaging of fura‐2 fluorescence, we found an elevation of intracellular cytoplasmic calcium in cortical astrocytes from neonatal Ts65Dn mouse brain, similar to that observed previously in embryonic Ts16 astrocytes. Furthermore, astrocytes from both Ts65Dn and Ts16 cortex fail to respond to the anti‐proliferative actions of glutamate. These results suggest that defective regulation of cell proliferation and cellular calcium can result from triplication of DS critical region genes. © 2003 Wiley‐Liss, Inc.
Effects of GDNF on 6‐OHDA‐induced death in a dopaminergic cell line: Modulation by inhibitors of PI3 kinase and MEK
Authors: Ugarte Susana D. , Lin Eva , Klann Eric , Zigmond Michael J. , Perez Ruth G.
Published: June 2003

Parkinson's disease is a neurodegenerative disorder associated with the selective death of dopaminergic neurons. Glial cell line‐derived neurotrophic factor (GDNF) can protect dopaminergic neurons in several parkinsonian models. We used the dopaminergic cell line MN9D to explore the mechanisms underlying GDNF‐mediated protection against the neurotoxin 6‐hydroxydopamine (6‐OHDA). MN9D cell viability was decreased 24 hr after a 15‐min exposure to 6‐OHDA (50–1,000 μM) as revealed by staining with Hoechst reagent and Trypan blue. The addition of GDNF (10 ng/ml) before, during, and after exposure to 6‐OHDA significantly increased the number of viable cells as assessed by Hoechst staining. In contrast, 6‐OHDA‐induced cell membrane damage was unaffected as measured by Trypan blue exclusion. The PI3K specific inhibitor LY294002 (10–50 μM) blocked GDNF‐mediated protection against nuclear condensation, as did the MAPK kinase (MEK) inhibitor U0126 (5– 20 μM). These studies suggest that GDNF can protect dopaminergic cells against some but not all aspects of 6‐OHDA‐induced toxicity by acting through both PI3K and MAPK signaling pathways. © 2003 Wiley‐Liss, Inc.
Hemin induces an iron‐dependent, oxidative injury to human neuron‐like cells
Authors: Goldstein Laurel , Teng Zhi‐Peng , Zeserson Eli , Patel Monica , Regan Raymond F.
Published: June 2003

Hemin is released from hemoglobin after CNS hemorrhage and is present at high micromolar concentrations in intracranial hematomas. This highly reactive compound is potentially cytotoxic via a variety of oxidative and nonoxidative mechanisms. However, despite its clinical relevance, little is known of its effect on neuronal cells. In this study, we tested the hypotheses that hemin is toxic to human neurons at physiologically relevant concentrations and that its toxicity is iron dependent and oxidative. A homogeneous population of neuron‐like cells was produced by sequential treatment of SH‐SY5Y cells with retinoic acid and brain‐derived neurotrophic factor, using the protocol of Encinas et al. Hemin exposure for 24 hr resulted in cell death that progressively increased between 3 and 30 μM (EC50 approximately 10 μM); protoporphyrin IX, the iron‐free congener of hemin, was not toxic. Cell death commenced at 14 hr and was preceded by a marked increase in cellular reactive oxygen species (ROS). Most injury and ROS production were prevented by concomitant treatment with an equimolar concentration of the lipid‐soluble iron chelator phenanthroline; the water‐soluble chelator deferoxamine was also effective at concentrations of 0.1 mM or higher. Heme oxygenase‐2 was constitutively expressed by these cells, and heme oxygenase‐1 was induced by hemin. Heme oxygenase inhibition attenuated ROS generation and reduced injury by about one‐third. Cell death was also prevented with the sulfhydryl reducing agents glutathione and mercaptoethanol. Nuclear morphology in the hours prior to cell lysis revealed a predominantly homogenous staining pattern; the percentage of fragmented nuclei was increased only at 4 hr and then accounted for only 1.45% ± 0.25% of cells. The general caspase inhibitor zVAD‐fmk had no effect on cell viability. These results suggest that hemin is toxic to human neuron‐like cells at concentrations that are less than 3% of those observed in intracranial hematomas. In this model, its toxicity is iron dependent, oxidative, and predominantly necrotic. © 2003 Wiley‐Liss, Inc.
Insulin‐like growth factor 1 is essential for normal dendritic growth
Authors: Cheng Clara M. , Mervis Ronald F. , Niu Shui‐Lin , Salem Norman , Witters Lee A. , Tseng Victor , Reinhardt Rickey , Bondy Carolyn A.
Published: June 2003

This study evaluated somatic and dendritic growth of neurons in the frontoparietal cortex of Igf1–/– brains. Pyramidal neuron density was increased by ∼25% (P = .005) and soma size reduced by ∼10% (P < .001). Golgi staining revealed that cortical layer II–III neurons exhibited a significant reduction in dendritic length and complexity in Igf1 null mice. Dendritic spine density and presumably synaptic contacts were reduced by 16% (P = .002). Similar findings were obtained for cortical layer V and piriform cortex pyramids. Supporting a reduction in synapses, synaptotagmin levels were reduced by 30% (P < .02) in the Igf1 null brain. Investigation of factors critically involved in dendritic growth and synaptogenesis showed an ∼50% reduction in cortical CDC42 protein expression (P < .001) and an ∼10% reduction in brain cholesterol levels (P < .01) in Igf1 null mice. Evidence is presented that Igf1 deletion causes disruptions in lipid and microtubule metabolism, leading to impaired neuronal somatic and dendritic growth. Published 2003 Wiley‐Liss, Inc.
Two populations of microglial cells isolated from rat primary mixed glial cultures
Authors: Kuwabara Yasuhide , Yokoyama Akiko , Yang Lihua , Toku Kazuko , Mori Kohji , Takeda Ikuko , Shigekawa Takako , Zhang Bo , Maeda Nobuji , Sakanaka Masahiro , Tanaka Junya
Published: June 2003

Because of variations in the morphology and function of microglial cells, it has often been claimed that microglial cells should be classified into two or more subtypes. However, such subtypes have not fully been characterized. In the present study, we isolated microglial cells expressing microglia‐markers CD11b and CD68 from rat mixed glial cultures on the fifth and on the thirteenth days in vitro (DIV 5 and 13) and demonstrate that these two populations of microglial cells have distinct morphology and function. Microglial cells isolated on DIV 5, which we have termed immature cells, are characterized by the presence of large somata, large peroxidase‐ and alkaline phosphatase‐positive granules, and high proliferative activity and suppressed responsiveness to lipopolysaccharide (LPS). In contrast, the microglial cells isolated on DIV 13, which we have termed mature cells, are devoid of granules, appear to be in a state of cell cycle arrest, and respond to LPS by the induction of inducible nitric oxide synthase (iNOS), tumor necrosis factor‐α, and interleukin‐6. Isolated immature cells maintained in pure culture failed to express iNOS in response to LPS. However, if these cells were cultured on astrocyte‐derived extracellular matrix (AsECM) or pure laminin, the cells exhibited an induction of iNOS in response to LPS. AsECM and laminin were also able to induce a state of cell cycle arrest in cultured isolated immature cells. Thus, classification into two types of microglial cells is possible, but both types are in the same cell lineage, because the immature cells can differentiate into mature microglial cells in the presence of laminin or AsECM. Therefore, “microglioblasts” may be the appropriate term for the immature cells. © 2003 Wiley‐Liss, Inc.
Expression of Foxp2, a gene involved in speech and language, in the developing and adult striatum
Authors: Takahashi Kaoru , Liu Fu‐Chin , Hirokawa Katsuiku , Takahashi Hiroshi
Published: June 2003

Many members of the forkhead/winged helix transcriptional factors are known to be regulators of embryogenesis. Mutations of the Fox gene family have been implicated in a range of human developmental disorders. Foxp2, a member of the Fox gene family, has recently been identified as the first gene that is linked to an inherited form of language and speech disorder. To elucidate the anatomical basis of language processing in the brain, we have examined the expression pattern of Foxp2 gene and its homologous gene, Foxp1, in the rat brain through development. Expression of Foxp2 mRNA was detected in the ventral telencephalon as early as embryonic day 13. Foxp2 mRNA was expressed primarily in differentiated cells of the lateral ganglionic eminence (striatal primordium). Of particular interest was that the developmental expression of Foxp2 followed a compartmetnal order in the striatum. Patches containing high levels of Foxp2 were aligned with patches enriched in mu‐opoid receptor, a marker for striosomal cells, in the striatum through postnatal development. Conversely, Foxp2‐positive patches were devoid of calbindin‐D28k, a maker for striatal matrix cells. Therefore, Foxp2 was preferentially expressed in striosomal compartment in the striatum during development. In the mature striatum, Foxp2 expression was maintained in striosomes, although its expression level was reduced. In contrast to Foxp2, Foxp1 was expressed in both the striosomal and matrix compartments in the striatum through development. The striatum is known to be involved in the process of procedural memory, and mutation of Foxp2 results in neurological disorders of language and speech. Given the preferential expression of Foxp2 in the striosomal compartment, the striatum, particularly the striosomal system, may participate in neural information processing for language and speech. Our suggestion is consistent with the declarative/procedural model proposed by Ullman and colleagues (Ullman et al. [1997] J. Cogn. Neurosci. 9:266–276; Ullman [2001] Nat. Rev. Neurosci. 2:717–726), in which the procedural memory‐dependent mental grammar is rooted in the basal ganglia and the frontal cortex and the declarative memory‐dependent mental lexicon is rooted in the temporal lobe. © 2003 Wiley‐Liss, Inc.
Cloning and expression of the rat BACE1 promoter
Authors: Lange‐Dohna Christine , Zeitschel Ulrike , Gaunitz Frank , Perez‐Polo J. Regino , Bigl Volker , Roßner Steffen
Published: June 2003

The pathogenic processing of the amyloid precursor protein (APP) into β‐amyloid peptides, which give rise to β‐amyloid plaques in the brains of Alzheimer's disease patients, requires the enzymatic activity of the beta‐site APP‐cleaving enzyme 1 (BACE1). We report the cloning and sequence of a 1.5‐kb DNA fragment upstream of the coding sequence of the rat BACE1 gene and the construction of a BACE1 promoter/luciferase reporter construct. The basal activity of this promoter construct was highest in neuronal cell lines such as BE(2)‐C and PC12 and in the pancreatic cell line AR42J, somewhat lower in rat primary neurons, and astrocytic and microglial cultures, very low in hepatocytes, and almost absent in fibroblasts and in the monocyte‐macrophage cell line RAW264.7. The first 600 bp of this promoter are highly conserved among rat, mouse, and human, suggesting that this region contains regulatory elements that modulate BACE1 transcription. Indeed, this fragment contains several putative transcription factor binding sites such as MZF1, Sp1, four GATA‐1 sites, and one YY1 site. Directed mutagenesis of GATA‐1 elements led to altered luciferase expression, indicating that these sites are involved in the regulation of BACE1 transcription. Additionally, the analysis of promoter activities of deletion mutants suggests the presence of activators of BACE1 transcription between bases −514 to −753 and of suppressor elements between bases −754 and −1541. The BACE1 promoter sequence data and the constructs described here will be useful to identify factors that influence the expression of BACE1 in experimental paradigms in vitro. © 2003 Wiley‐Liss, Inc.
Spontaneous central nervous system remyelination is not altered in NFH‐lacZ transgenic mice after chemical demyelination
Authors: Jean Isabelle , Fressinaud Catherine
Published: June 2003

Harmonious functioning of the nervous system depends on neuron–glia interactions, particularly between the axons and their myelinating cells, i.e., oligodendrocytes (OL) in the central nervous system (CNS). In human demyelinating diseases such as multiple sclerosis (MS), demyelination may be associated with axonal damage, but alterations of the axonal cytoskeleton, which is composed mainly of neurofilaments (NF) and microtubules, are largely unknown, as are the consequences on remyelination. In a model of demyelination induced by lysophosphatidylcholine (LPC), we have shown that demyelination was correlated with a decrease in NF immunolabelling, and that these axonal abnormalities were reduced by platelet‐derived growth factor (PDGF)‐enhanced remyelination in adult rats. We have analysed the spontaneous remyelination after LPC stereotaxic injection in the CNS of transgenic NFH‐lacZ mice, which present axonal atrophy caused by abnormal distribution of NF, associated with hypermyelination in the PNS, and normal myelin thickness in the CNS. Axonal atrophy in the CNS of NFH‐lacZ mice was confirmed, but it was not worsened by demyelination. On the contrary, demyelination induced axonal atrophy in wild‐type mice, demonstrating that NF are essential for axonal calibre determination. Moreover, an efficient spontaneous remyelination occurred in NFH‐lacZ as well as in wild‐type mice, indicating that the NF are not necessary for CNS remyelination. These findings point out that NF modifications observed in MS may not be responsible for the lack of remyelination in this disease. © 2003 Wiley‐Liss, Inc.
Regulation of CNS glial phenotypes in N20.1 cells
Authors: Studzinski Diane M. , Benjamins Joyce A.
Published: June 2003

The N20.1 oligodendroglial cell line, immortalized with SV40 T antigen, simultaneously expresses oligodendroglial markers and glial fibrillary acidic protein (GFAP), an astroglial marker. This study examines the plasticity of N20.1 cells with regard to GFAP expression, and its relationship to expression of SV40 T antigen, p53, and a novel nuclear antigen detected by the A007 monoclonal antibody. Marked changes occur in GFAP levels and cell morphology when N20.1 cells are switched from the permissive temperature (34°C) to the non‐permissive temperature (39°C), and with cyclic AMP elevation at 39°C. At 34°C, levels of GFAP are high; when cells are switched to 39°C, GFAP levels decrease significantly, then increase slightly when forskolin is added. At both temperatures, the cells display feathery GFAP immunostaining. When forskolin is added at 39°C, however, cells display bright fibrous GFAP staining in elongated processes. The changes in GFAP were compared to changes in T antigen and p53. As expected, the decrease in T antigen at 39°C was accompanied by movement of p53 from the nucleus to cytoplasm. Total p53 levels did not change, however, and forskolin did not alter the respective distribution or levels of p53 at either temperature. At both temperatures, the cell bodies and processes show internal expression of sulfatide, as demonstrated with the O4, Sulph I, and A007 antibodies. We show, for the first time, abundant nuclear immunoreactivity with the A007 monoclonal antibody in the N20.1 cells. This nuclear reactivity is seen at 34°C, but not at 39°C, similar to p53, and is not detected with the other sulfatide antibodies. Double‐label immunostaining shows that the nuclear A007 immunoreactivity is co‐localized in nuclear structures with T antigen and p53 at 34°C, but is not found in every nucleus containing these antigens. We conclude that regulation of GFAP expression and morphology in N20.1 cells is dependent on a combination of T antigen expression and level of cAMP and may be related to regulation of p53 and the A007 nuclear antigen. © 2003 Wiley‐Liss, Inc.
Fractalkine protein localization and gene expression in mouse brain
Authors: Tarozzo G. , Bortolazzi S. , Crochemore C. , Chen S.‐C. , Lira A.S. , Abrams J.S. , Beltramo M.
Published: June 2003

Few chemokines are expressed constitutively in the brain at detectable levels; amongst them is fractalkine. We analyzed the distribution of fractalkine in the mouse brain with the aim of giving a neuroanatomical support to the study of its physiological function. To this end, we carried out an analysis of fractalkine protein localization and gene expression. An anti‐fractalkine antibody was produced and used to perform an immunohistochemical study. The results indicated a high level of fractalkine protein in cortex, hippocampus, basal ganglia, and olfactory bulb. In particular, the presence of abundant immunoreactive neurons was observed in layers II, III, V, and VI of the cortex. In the hippocampus, the CA1 region was the most intensely labeled, but immunoreactive neurons were present also in CA2 and CA3, whereas in the basal ganglia, immunoreactive cells were observed in the caudate putamen. Other brain structures such as the brainstem showed a few scattered immunoreactive cells. The presence of fractalkine immunoreactive fibers was revealed only in the olfactory bulb and in the anterior olfactory nuclei. Gene expression study results, obtained by both semiquantitative PCR and in situ hybridization, matched protein localization with the highest levels of fractalkine transcript detected in the hippocampus, cortex, and striatum. The present study showed that fractalkine protein and mRNA are constitutively expressed at a high level in forebrain structure, but are almost absent in the hindbrain. Furthermore, localization at the cellular body level would suggest a paracrine or cell‐to‐cell interaction role for fractalkine more than a neurotransmission modulatory function. © 2003 Wiley‐Liss, Inc.
The art of listening
Authors: Hesselbein Frances
Published: June 2003

It's all about respect, appreciation, anticipation—and leadership.
The leadership journey
Authors: Kahn Philippe
Published: June 2003

Cutting‐edge technology doesn't go far without teamwork.
Building better business models
Authors: Mitchell Donald W. , Coles Carol Bruckner
Published: June 2003

Today's leaders must continually remodel.
The leadership‐teamship‐followership continuum
Authors: Townsend Patrick L. , Gebhardt Joan E.
Published: June 2003

Everyone needs to be comfortable in and effective at three key roles.
The energizing leader
Authors: Spitzer Dean
Published: June 2003

How leaders at all levels mobilize the energies of people to achieve extraordinary results.
Getting the power equation right
Authors: Tichy Noel M.
Published: June 2003

Leaders who succeed recognize the importance of building a team at the top.
The discipline of collaboration
Authors: Linden Russ
Published: June 2003

Collaborative leaders must balance competing and shifting requirements.
Inspiring hope to mobilize change
Authors: Chronister Paula L.
Published: June 2003

How to sustain people through the discomfort and stress that inevitably come with change.
Structural Characterization and Degradability of Poly(L‐lactic acid)s Incorporating Phenyl‐Substituted α‐Hydroxy Acids as Comonomers
Authors: Moon Sung‐Il , Urayama Hiroshi , Kimura Yoshiharu
Published: June 2003

Three types of copolymers of poly(L‐lactic acid) (PLLA) were synthesized by direct polycondensation of L‐lactic acid and phenyl‐substituted α‐hydroxy acids (L‐phenyllactic acid and D‐ and L‐mandelic acids). It was found that the glass transition temperature of the copolymers comprising L‐mandelic acid became significantly higher (from 58 to 69 °C) with increasing content of L‐mandelic acid (from 0 to 50 mol‐%) although the Mw decreased (from 87 000 to 4 000 Da). The cast films of the L‐mandelic acid containing copolymers showed improved tensile properties compared with those of the PLLA film. This may be due to a pinning effect of the L‐mandelic acid units on the helix formation of PLLA, although 30% of the units were racemized. The enzymatic degradability of the L‐mandelic acid containing copolymers was much higher than that of PLLA, as analyzed with Proteinase K® originating from Tritirachium album.

Synthesis of copolymers of L‐lactic acid and phenyl‐substituted α‐hydroxy acids.

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Synthesis of copolymers of L‐lactic acid and phenyl‐substituted α‐hydroxy acids.
Phase Behavior and Thermal Properties for Binary Blends of Bacterial Poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate)s with Narrow‐Comonomer‐Unit Compositional Distribution
Authors: Feng Lidan , Watanabe Takumi , He Yong , Wang Yi , Kichise Tomoyasu , Fukuchi Takeshi , Chen Guo‐Qiang , Doi Yoshiharu , Inoue Yoshio
Published: June 2003

The miscibility and the effect of compositional distribution on physical properties were investigated for binary blends of biosynthesized poly(3‐hydroxybutyrate) [P(3HB)] and comonomer compositionally fractionated poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate)s [P(3HB‐co‐3HH)] with narrow compositional distribution. Biosynthesized P(3HB‐co‐3HH) samples were compositionally fractionated using solvent (chloroform)/nonsolvent (n‐heptane) mixtures. The binary blends of fractionated P(3HB‐co‐3HH)s with different 3HH unit content were prepared by casting from solution in chloroform. The miscibility and the thermal properties of these blends were analyzed by differential scanning calorimetry (DSC). It was found that the two components are miscible in the amorphous phase when the difference in 3HH unit content between the two component polymers of these blends is less than 20 mol‐%, subsequently they are immiscible when the difference is larger than 30 mol‐%. By comparing the thermal properties of the binary blends of fractions, with those for the fractions themselves, and with those for the bacterially as‐produced unfractionated copolyesters, the effects of compositional distribution on the properties of copolyesters were discussed.

Glass transition temperatures of blends PHB/H10, H10/H20, and PHB/H20 versus total 3HH unit content in the blends. The solid lines are the best fits of the experimental results of the P(3HB‐co‐3HH) fractions with narrow compositional distribution.

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Glass transition temperatures of blends PHB/H10, H10/H20, and PHB/H20 versus total 3HH unit content in the blends. The solid lines are the best fits of the experimental results of the P(3HB‐co‐3HH) fractions with narrow compositional distribution.
Antioxidant Activity of Graft Chitosan Derivatives
Authors: Sun Tao , Xie Wenming , Xu Peixin
Published: June 2003

Graft chitosan derivatives (CMCTS‐g‐MAAS and CMCTS‐g‐AAS) were prepared by the graft copolymerization of methacrylic acid sodium (MAAS) and acrylic acid sodium (AAS) onto the etherification product of chitosan‐carboxymethyl chitosan (CMCTS). Their antioxidant activity was estimated as superoxide anion scavengers by chemiluminescence techniques. The derivatives with low grafting percentages have a relatively low 50% inhibition concentration (IC50), which could be related to the fact that they have different contents of hydroxyl and amino groups in the polymer chains.

Superoxide radical scavenging activity of CMCTS‐g‐MAAS.

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Superoxide radical scavenging activity of CMCTS‐g‐MAAS.
Hydrolytic and Thermal Degradation of Random Copolyesters of ε‐Caprolactone and 2‐Oxepane‐1,5‐dione
Authors: Dwan'Isa Jean‐Pierre Latere , Lecomte Philippe , Dubois Philippe , Jérôme Robert
Published: June 2003

The hydrolytic and thermal stability of random copolyesters of ε‐caprolactone (ε‐CL) and ca. 30 mol‐% 2‐oxepane‐1,5‐dione (OPD) have been investigated. Compared with poly(ε‐caprolactone) (PCL) of a comparable molecular weight, the hydrolytic degradation of the copolyester is faster in a phosphate buffer (pH = 7.4) at 37 °C as confirmed by the time dependence of water absorption, weight loss, melting temperature, and molecular weight. This difference is a result of the higher hydrophilicity imparted to the copolyester by the ketone of the OPD units. The thermal degradation has been studied by thermogravimetric analysis (TGA), 1H NMR spectroscopy, and size exclusion chromatography (SEC). The activation energy of the thermal degradation under nitrogen has been found to be lower for the copolyesters than for PCL, which indicates that the OPD co‐units have a deleterious effect on the thermal stability of PCL. The thermal degradation primarily occurs by pyrolysis of the ester functions.

Pyrolysis of the ester function of the ε‐CL/OPD diad.

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Pyrolysis of the ester function of the ε‐CL/OPD diad.
Thermo‐Responsive and Emulsifying Properties of Poly(N‐vinylcaprolactam) Based Graft Copolymers
Authors: Verbrugghe Sam , Bernaerts Katrien , Du Prez Filip E.
Published: June 2003

Thermo‐responsive graft copolymers have been synthesized based on a poly(N‐vinylcaprolactam) (PVCL) backbone and either hydrophilic poly(ethylene oxide) (PEO) or hydrophobic poly(tetrahydrofuran) (PTHF) side chains. The phase separation behavior of the graft polymers in water was studied by transmittance measurements and compared to that of the corresponding swollen segmented polymer networks and aqueous solutions of both polymers. The influence of the concentration and length of the grafts on the cloud point temperature (TCP) has been demonstrated. PVCL‐g‐PTHF copolymers have been synthesized by using the macromonomer technique, i.e. the radical copolymerization of VCL with a PTHF macromonomer. A special feature of these amphiphilic graft copolymers is their ability to stabilize aqueous emulsions below the TCP and to suddenly break them above the TCP. PVCL‐g‐PEO copolymers were prepared by a grafting onto method. First, succinimide groups were introduced in the backbone, to which amino terminated PEO chains were grafted in the second step. This leads to di‐hydrophilic copolymers that become amphiphilic after heating their aqueous solutions above the TCP.

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Donaldson–Friedman construction and deformations of a triple of compact complex spaces, II
Authors: Honda Nobuhiro
Published: June 2003

In a previous paper of the same title the author gave a generalization of the constrution of Donaldson–Friedman, to prove the existence of twistor spaces of nCP2 with a special kind of divisors. In the present paper, we consider its equivariant version. When n = 3, this gives another proof of the existence of degenerate double solid with C*–action, and we show that the branch quartic surface is birational to an elliptic ruled surface. In case n ≥ 4, this yields new Moishezon twistor spaces with C*–action, which is shown to be the most degenerate ones among twistor spaces studied by Campana and Kreußler.
Integral representation for exponentially bounded negative–definite functions on hypergroups
Authors: Nasr–Isfahani R.
Published: June 2003

The author has recently shown that a Bochner type theorem obtained by Bloom and Ressel for exponentially bounded positive–definite functions on second countable commutative hypergroups is valid for all commutative hypergroups X. Here an application of this result is made to give an integral representation for exponentially bounded negative–definite functions on X.
On the axiomatic definition of real JB*–triples
Authors: Peralta Antonio M.
Published: June 2003

In the last twenty years, a theory of real Jordan triples has been developed. In 1994 T. Dang and B. Russo introduced the concept of J*B–triple. These J*B–triples include real C*–algebras and complex JB*–triples. However, concerning J*B–triples, an important problem was left open. Indeed, the question was whether the complexification of a J*B–triple is a complex JB*–triple in some norm extending the original norm. T. Dang and B. Russo solved this problem for commutative J*B–triples.

In this paper we characterize those J*B–triples with a unitary element whose complexifications are complex JB*–triples in some norm extending the original one. We actually find a necessary and sufficient new axiom to characterize those J*B–triples with a unitary element which are J*B–algebras in the sense of [1] or real JB*–triples in the sense of [4].
Polyelectrolyte Multilayers on Weak Polyelectrolyte Brushes
Authors: Zhang Haining , Rühe Jürgen
Published: June 2003

The interaction of surface‐attached weak polyelectrolyte brushes, grown directly from the surface of a solid substrate by surface‐initiated polymerization, with weak polyelectrolyte molecules in solution is studied. In addition, the formation of PEL multilayers onto such brush substrates is investigated. A strong template effect is observed and the thickness of each adsorbed layer is closely related to the thickness of the initial brush. Thus monolayers of more than 100 nm can be adsorbed in one single dipping cycle.

Layer thickness of PEI layers adsorbed to PMAA brushes as a function of the thickness of the surface‐attached monolayer. The solid line represents a case in which the PEI layer has exactly the same thickness as the brush monolayer.

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Layer thickness of PEI layers adsorbed to PMAA brushes as a function of the thickness of the surface‐attached monolayer. The solid line represents a case in which the PEI layer has exactly the same thickness as the brush monolayer.
A New Approach to High‐Capacity Functionalized Monoliths via Post‐Synthesis Grafting
Authors: Lubbad Said , Buchmeiser Michael R.
Published: June 2003

A new approach toward the grafting of norborn‐2‐ene derivatives onto ROMP‐based monolithic supports has been developed. Grafting yields were governed by three variables, which are the catalyst, temperature and the crosslinker used. Three different catalysts, three grafting temperatures, as well as two different crosslinkers were investigated. By optimizing all variables 4‐fold amounts of grafted monomers compared to previously reported procedures were obtained reaching values of 1.04 mmol of monomer/g monolith.

Grafted monolithic supports applying the method reported here.

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Grafted monolithic supports applying the method reported here.
Synthesis of Poly(methyl methacrylate) Nanosize Particles by Differential Microemulsion Polymerization
Authors: He Guangwei , Pan Qinmin , Rempel Garry L.
Published: June 2003

Poly(methyl methacrylate) nanosize particles were synthesized by a differential microemulsion polymerization process. Sodium dodecylsulfate and ammonium persulfate were used as the surfactant and initiator, respectively. The effects of reaction conditions on the particle size have been investigated. A particle size of less than 20 nm in diameter has been achieved with surfactant/monomer and surfactant/water weight ratios of 1:18 and 1:120, i.e. much milder conditions than those previously reported in the literature.

TEM image of nanoparticles prepared via differential microemulsion polymerization.

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TEM image of nanoparticles prepared via differential microemulsion polymerization.
Tandem mass spectrometry in the study of fatty acids, bile acids, and steroids
Authors: Griffiths William J.
Published: June 2003

I.
Introduction
82

 II.
Collision‐Energy Effects and Charge‐Remote Fragmentation
83

III.
Fatty Acids and Related Lipids
85

A.  Saturated and Unsaturated Fatty Acids
85

B.  Hydroxy‐Polyunsaturated Fatty Acids and Eicosanoids
89

C.  Derivatization of Fatty Acids for FAB and ES Analysis
90

D.  Fatty Alcohols and Aldehydes
94

 IV.
Complex Lipids
96

A.  Phospholipids
97

B.  Triacylglycerols
106

  V.
Bile Acids and Conjugated Steroids
112

A.  Bile Acids
112

B.  Steroid Conjugates: Sulfates and Glucuronides
115

C.  Mechanism of Fragmentation of Bile Acids, Steroid Sulfates, and Steroid Glucuronides
126

    1.  Side‐Chain Fragmentation
127

    2.  Ring Fragmentation
127

    3.  Sulfate Fragmentation
128

    4.  Bile Acid Fragmentation
128

 VI.
Neutral Steroids
128

A.  Estradiol Metabolites and Synthetic Derivatives
128

B.  Oxosteroids and Their Derivatives
131

    1.  3‐Oxo‐Δ4‐Steroid 3‐Oximes
132

    2.  20‐Oxosteroid and 17‐Oxosteroid Oximes
133

    3.  Methyl Oximes
134

    4.  Underivatized Oxosteroids
134

    5.  Steroid Esters
138

    6.  Girard T Hydrazone
139

VII.
Novel Derivatives of Neutral Steroids
140

VIII.
Conclusions
142

Acknowledgments

143

Appendix

143

  A.
Abbreviations and Relevant References
143

  B.
Use of the Prime
144

  C.
Some Steroid Structures
145

References

145

Over the last 50 years, the mass spectrometry of lipids has evolved to become one of the most mature techniques in biomolecule analysis. Many volatile and non‐polar lipids are directly amenable to analysis by gas‐chromatography‐mass spectrometry (GC‐MS), a technique that combines the unsurpassed separation properties of gas‐chromatography with the sensitivity and selectivity of electron ionization mass spectrometry. Less volatile and/or thermally labile lipids can be analyzed by GC‐MS, following appropriate sample derivatization. However, many complex lipids are not readily analyzed by GC‐MS, and it is these molecules that are the subject of the current review. Since the early 1970s, there have been three outstanding developments in mass spectrometry that are particularly appropriate in lipid analysis; i.e., the introduction of (i) fast atom bombardment (FAB); (ii) electrospray (ES); and (iii) tandem mass spectrometry (MS/MS). The FAB and ES ionization techniques will be discussed in relation to MS/MS, and examples of their application in biochemical studies will be presented. The review will concentrate on the analysis of fatty acids, bile acids, steroid conjugates, and neutral steroids. © 2003 Wiley Periodicals, Inc., Mass Spec Rev 22:81–152, 2003; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/mas.10046
Untersuchung zur Schichtfolge eines Multilayerschichtsystems NiZn Ferrit / Si bzw. SiO2für Höchstfrequenzleiterplatten im Frequenzbereich größer 1000 MHz
Authors: Gräbner F. , Teichert G. , Knedlik Ch. , Hildenbrand S. , Romanus H. , Hungsberg A. , Koledintseva M.
Published: June 2003

Es ist gelungen mittels des Sputterverfahrens ferritische Multilayerschichten auf HF‐Leiterplattenmaterial der Firmen Rogers (USA) und Mauritz ( Germany) abzuscheiden.

Es wurde eine fast linear anwachsende Reflexionsdämpfung von 0,6 dB ab 1000 MHz bis 77000 MHz gemessen. Die theoretische Betrachtung mit einem numerischen Simulator 2DTLM zum Schichtfolgeaufbau konnte im Experiment in der Striplineanordnung bis 3800 MHZ diskutiert werden. Theoretische Simulationsergebnisse weisen auf gute Dämpfungsergebnisse bei einem Schichtaufbau mit Anordnung einer Ferritschicht am Metallabschluß hin.
Zum Korrosions‐ und Verschleißverhalten von Nickeldispersionsschichten mit Nanopartikeln
Authors: Steinhäuser S. , Lampke Th. , Wielage B. , Erler F. , Jakob C.
Published: June 2003

Diese Arbeit berichtet über die Ergebnisse der elektrochemischen Abscheidung von Nickeldispersionsschichten mit nanoskaligen Partikeln aus einem Watts Elektrolyten. Es werden Aussagen zu erzielten Einbauraten und daraus resultierenden Gefügen und mechanischen Eigenschaften getroffen. Von besonderer Bedeutung für die Anwendung der abgeschiedenen Schichten sind deren Korrosions‐ und Verschleißverhalten. Mit Hilfe von Stromdichte‐Potenzialmessungen und optischen Untersuchungsmethoden ist das Korrosionsverhalten in Abhängigkeit von den Feststoffen und organischen Zusätzen bewertbar. Eine Steigerung der Korrosionsbeständigkeit durch nanoskalige Teilchen wurde nicht festgestellt. Sehr positiv wirken sich die inkorporierten Partikel auf das Verschleißverhalten, ermittelt im Schwingverschleißtribometer, aus.
Thermisches Bonden von Bauteilen aus mikrostrukturiertem Glas
Authors: Hecht‐Mijic St. , Harnisch A. , Hülsenberg D. , Schundau S. , Pfeifer J. , Schroeter Th.
Published: June 2003

An der TU Ilmenau erfolgte die Entwicklung von mikrostrukturierbaren Gläsern und von mikrostrukturierbaren Gläsern mit besonderen pH‐sensitiven Eigenschaften. Die Gläser sind über eine UV‐Lithographietechnik mikrostrukturierbar. Zum Aufbau von chemischen Sensoren ist das Fügen von derartigen Glasbauteilen erforderlich. Im Beitrag werden das thermische Bonden als ein mögliches Fügeverfahren vorgestellt und Versuchsergebnisse diskutiert. Vorteile des Verfahrens sind die stabile Verbindungsausbildung und das werkstoffkonforme Fügen ohne Zusatzstoffe.