bluuebunny/crossref_metadata_2025 huggingface dataset:
A role for chemokines in the induction of chondrocyte phenotype modulation
Authors: Mazzetti Ilaria , Magagnoli Giorgia , Paoletti Samantha , Uguccioni Mariagrazia , Olivotto Eleonora , Vitellozzi Roberta , Cattini Luca , Facchini Andrea , Borzì Rosa Maria
Published: January 2004

Objective

To extend the study of the chemokine receptor repertoire on human chondrocytes to receptors with reported housekeeping functions (CXCR3, CXCR4, CXCR5, and CCR6) and to evaluate whether ligands of these receptors play a role in chondrocyte phenotype modulation and proliferation.

Methods

Chemokine receptor expression was determined by flow cytometry. Subcultures of chondrocytes were collected and fixed at confluence or during the exponential phase of growth and analyzed for chemokine receptor modulation. The effects of chemokines on isolated cells as well as chondrocytes cultured within an intact extracellular matrix were investigated. Isolated human chondrocytes were stimulated with 100 nM chemokines (monokine induced by interferon‐γ, stromal cell–derived factor 1α [SDF‐1α], B cell–attracting chemokine 1 [BCA‐1], or macrophage inflammatory protein 3α), and conditioned media were assessed for matrix‐degrading enzyme contents (matrix metalloproteinases [MMPs] 1, 3, and 13, and N‐acetyl‐β‐D‐glucosaminidase [NAG]). Cell proliferation and phenotype modulation were evaluated by bromodeoxyuridine incorporation and cathepsin B production. Induction of cell proliferation was assessed in cartilage explants by immunodetection of the proliferation‐associated antigen S100A4.

Results

CXCR3, CXCR4, CXCR5, and CCR6 were detected on human chondrocytes. CXCR3 and CXCR4 expression was increased in exponentially growing chondrocyte subcultures. Ligands of all receptors enhanced the release of MMPs 1, 3, and 13. Release of NAG and cathepsin B was significantly higher in chemokine‐stimulated cultures than in unstimulated cultures. SDF‐1α and BCA‐1 also induced DNA synthesis and chondrocyte proliferation, as was shown by the up‐regulation of S100A4 in cartilage explants as well.

Conclusion

Our findings extend the repertoire of functional responses elicited by the activity of chemokines on chondrocytes and open new avenues in our understanding of the control of chondrocyte differentiation status by chemokines and their receptors.
Progression of radiologic damage in patients with rheumatoid arthritis in clinical remission
Authors: Molenaar Esmeralda T. H. , Voskuyl Alexandre E. , Dinant Huib J. , Bezemer P. Dick , Boers Maarten , Dijkmans Ben A. C.
Published: January 2004

Objective

To assess whether radiologic progression occurs during clinical remission in patients with rheumatoid arthritis (RA).

Methods

One hundred eighty‐seven patients with RA in clinical remission were followed up clinically and radiologically for 2 years. Clinical remission was defined according to a modification of the American College of Rheumatology criteria (i.e., the criterion of fatigue was omitted, and patients had to fulfill 4 of the 5 remaining criteria). Radiologic joint damage was assessed by the Sharp/van der Heijde method.

Results

After 2 years of followup, remission persisted in 52% of patients. The median radiologic score for the total group of patients increased from 21 (interquartile range [IQR] 5, 65) at the time of entry to 25 (IQR 7, 72) after 2 years (P < 0.001). The median score for radiologic progression between baseline and 2 years was 0.5 (IQR 0, 2.5). Among patients with an exacerbation of RA (n = 86), the median score for progression over 2 years was 1.0 (IQR 0, 4.5) (P < 0.001), and in patients with a persistent remission (n = 93) it was 0 (IQR −0.5, 2.0) (P < 0.001). Clinically relevant progression of damage was more frequent in patients with exacerbation (23%) than in those with persistent remission (7%) (P = 0.001). However, in 15% of patients with persistent remission, an erosion developed in a previously unaffected joint. In the logistic regression analysis, the area under the curve of the Disease Activity Score, a continuous measure, was related to the chance of radiologic progression, regardless of the absolute disease activity level. Results were similar when other definitions of remission were used.

Conclusion

Although rare, clinically relevant progression of joint damage does occur in patients with RA in prolonged remission. This suggests the need for markers that predict progression during periods of low disease activity and for drugs that prevent damage that is independent of disease activity.
Longitudinal study of changes in tibial and femoral cartilage in knee osteoarthritis
Authors: Cicuttini F. M. , Wluka A. E. , Wang Y. , Stuckey S. L.
Published: January 2004

Objective

Despite the increasing interest in knee cartilage volume as an outcome measure in studies of osteoarthritis (OA), it is unclear what components of knee cartilage will be most useful as markers of structural change in the tibiofemoral joint. This study was undertaken to longitudinally compare changes in femoral and tibial cartilage volume in patients with OA.

Methods

One hundred seventeen patients with knee OA (58.1% women; mean ± SD age 63.7 ± 10.2 years) were examined. Femoral and tibial cartilage volumes (medial and lateral tibiofemoral joints) were determined from T1‐weighted fat‐saturated magnetic resonance images of the knee from coronal views.

Results

The study population was followed up for a mean ± SD of 1.9 ± 0.2 years. In the medial tibiofemoral joint, the mean ± SD loss of cartilage was 0.15 ± 0.30 ml/year for femoral cartilage and 0.10 ± 0.25 ml/year for tibial cartilage. In the lateral tibiofemoral joint, the average loss was 0.15 ± 0.22 and 0.12 ± 0.16 ml/year for femoral and tibial cartilage, respectively. There was a significant correlation between the degree of loss of tibial cartilage and the degree of loss of femoral cartilage, in both tibiofemoral joints (r = 0.81, P < 0.001 at the medial tibiofemoral joint; r = 0.71, P < 0.001 at the lateral tibiofemoral joint).

Conclusion

Longitudinal changes in tibial cartilage and those in femoral cartilage are strongly related to one another. This suggests that in tibiofemoral disease, measuring tibial cartilage alone may be adequate, given the facts that measurements of the total femoral cartilage are less reproducible and there are difficulties inherent in identifying the most appropriate component of femoral cartilage to measure.
Anti–signal recognition particle autoantibody in patients with and patients without idiopathic inflammatory myopathy
Authors: Kao Amy H. , Lacomis David , Lucas Mary , Fertig Noreen , Oddis Chester V.
Published: January 2004

Objective

To determine the long‐term outcome and associated clinical, serologic, and pathologic features in a cohort of patients with connective tissue disease (CTD) and the anti–signal recognition particle (anti‐SRP) autoantibody.

Methods

Sera and clinical data were collected prospectively from consecutive adult patients with polymyositis (PM; n = 134), dermatomyositis (n = 129), or other CTDs (predominantly systemic sclerosis [SSc; n = 790]). Patients were first evaluated during 1973–2001.

Results

Nineteen patients with the anti‐SRP autoantibody were identified, 16 (84%) of whom had pure PM and 3 (2 with SSc and 1 with antisynthetase syndrome) had yet to develop features of myositis after a mean followup of 4.5 years (range 2.5–6 years). More SRP‐positive PM patients had severe proximal muscle weakness (50%) and muscle atrophy (67%) at initial presentation compared with antisynthetase‐positive PM controls. Cardiac involvement occurred in only 2 of 16 SRP‐positive PM patients (13%), and interstitial lung disease was noted in 3 of 13 SRP‐positive PM patients (23%) and in the 3 SRP‐positive nonmyositis patients. There was a relative lack of inflammation in muscle biopsy specimens from the SRP‐positive PM cohort. Other autoantibodies in the SRP‐positive patients included Ro/SSA (4 patients), Th/To (1 patient), and anti–PL‐12 (1 patient). Survival in the SRP‐positive PM patients was comparable with that seen in the cohort of SRP‐negative PM patients.

Conclusion

The anti‐SRP autoantibody is not specific for PM. Severe muscle weakness and atrophy were prominent features in PM patients with anti‐SRP. Cardiac involvement was less common and survival was better in patients with anti‐SRP than has previously been reported.
Selective cleavage of nucleolar autoantigen B23 by granzyme B in differentiated vascular smooth muscle cells: Insights into the association of specific autoantibodies with distinct disease phenotypes
Authors: Ulanet Danielle B. , Flavahan Nicholas A. , Casciola‐Rosen Livia , Rosen Antony
Published: January 2004

Objective

To investigate the association of specific autoantibodies with distinct disease phenotypes. The association of autoantibodies to nucleophosmin/B23 with pulmonary hypertension in scleroderma, and the susceptibility of autoantigens to cleavage by granzyme B (GB), provided a focus for these studies.

Methods

Intact cells were subjected to cytotoxic lymphocyte granule–induced death, and the susceptibility of autoantigens to cleavage by GB was addressed by immunoblotting and/or by a novel immunofluorescence assay.

Results

B23 was cleaved efficiently by GB in vitro, but was highly resistant to cleavage by GB during cytotoxic lymphocyte granule–mediated death of many intact cell types. In contrast, this molecule was highly susceptible to GB‐mediated proteolysis exclusively in differentiated vascular smooth muscle cells. Topoisomerase I and several other GB substrates did not show this striking change in cleavage susceptibility in different cell types.

Conclusion

These data demonstrate that the cleavage of B23 by GB in intact cells is dependent upon both cell type and phenotype. The susceptibility of this autoantigen (which is associated with a distinct pulmonary vascular phenotype in scleroderma) to GB‐mediated proteolysis selectively in vascular smooth muscle cells suggests that the GB‐cleavable conformation of autoantigens may occur selectively in the target tissue, and may play a role in shaping the phenotype‐specific autoimmune response.
Single and combined inhibition of tumor necrosis factor, interleukin‐1, and RANKL pathways in tumor necrosis factor–induced arthritis: Effects on synovial inflammation, bone erosion, and cartilage destruction
Authors: Zwerina Jochen , Hayer Silvia , Tohidast‐Akrad Makiyeh , Bergmeister Helga , Redlich Kurt , Feige Ulrich , Dunstan Colin , Kollias Giorgos , Steiner Günter , Smolen Josef , Schett Georg
Published: January 2004

Objective

To investigate the efficacy of single and combined blockade of tumor necrosis factor (TNF), interleukin‐1 (IL‐1), and RANKL pathways on synovial inflammation, bone erosion, and cartilage destruction in a TNF‐driven arthritis model.

Methods

Human TNF–transgenic (hTNFtg) mice were treated with anti‐TNF (infliximab), IL‐1 receptor antagonist (IL‐1Ra; anakinra), or osteoprotegerin (OPG; an OPG‐Fc fusion protein), either alone or in combinations of 2 agents or all 3 agents. Synovial inflammation, bone erosion, and cartilage damage were evaluated histologically.

Results

Synovial inflammation was inhibited by anti‐TNF (−51%), but not by IL‐1Ra or OPG monotherapy. The combination of anti‐TNF with either IL‐1Ra (−91%) or OPG (−81%) was additive and almost completely blocked inflammation. Bone erosion was effectively blocked by anti‐TNF (−79%) and OPG (−60%), but not by IL‐1Ra monotherapy. The combination of anti‐TNF with IL‐1Ra, however, completely blocked bone erosion (−98%). Inhibition of bone erosion was accompanied by a reduction of osteoclast numbers in synovial tissue. Cartilage destruction was inhibited by anti‐TNF (−43%) and was weakly, but not significantly, inhibited by IL‐1Ra, but was not inhibited by OPG monotherapy. The combination of anti‐TNF with IL‐1Ra was the most effective double combination therapy in preventing cartilage destruction (−80%). In all analyses, the triple combination of anti‐TNF, IL‐1Ra, and OPG was not superior to the double combination of anti‐TNF and IL‐1Ra.

Conclusion

Articular changes caused by chronic overexpression of TNF are not completely blockable by monotherapies that target TNF, IL‐1, or RANKL. However, combined approaches, especially the combined blockade of TNF and IL‐1 and, to a lesser extent, TNF and RANKL, lead to almost complete remission of disease. Differences in abilities to block synovial inflammation, bone erosion, and cartilage destruction further strengthen the rationale for using combined blockade of more than one proinflammatory pathway.
Oligodeoxynucleotides containing CpG motifs can induce T cell–dependent arthritis in rats
Authors: Svelander Lena , Erlandsson Harris Helena , Lorentzen Johnny C. , Trollmo Christina , Klareskog Lars , Bucht Anders
Published: January 2004

Objective

To investigate whether CpG oligodeoxynucleotides (ODNs) can induce or accelerate arthritis in rats.

Methods

The CpG‐induced response was studied by recording joint inflammation, cell activation in draining lymph nodes, and levels of the acute‐phase reactant α1‐acid glycoprotein (AGP) in sera. The role of T cells was investigated by in vivo administration of monoclonal antibodies specific for the T cell receptor α/β (TCRα/β), followed by analysis of cell phenotypes by flow cytometry.

Results

One intradermal injection of CpG ODN emulsified with Freund's incomplete adjuvant (IFA) induced arthritis in LEW and LEW.1AV1 rats, while the control ODN sequence without CpG motifs or IFA alone did not trigger disease. The CpG/IFA and control‐ODN/IFA injections induced lymphoplasia as well as elevated levels of interleukin‐1β and interferon‐γ messenger RNA in lymph nodes. The arthritis was preceded by elevated levels of AGP in serum. In vivo administration of anti‐TCRα/β antibodies after disease induction caused decreased expression of the TCR–CD3 complex on circulating T cells and ameliorated the arthritis.

Conclusion

We demonstrated that injection with immunostimulatory CpG, both in phosphorothioate‐modified and native forms, can induce a T cell–dependent joint‐specific inflammation in LEW and LEW.1AV1 rat strains. This arthritis is preceded by signs of activation of the innate immune system. Since unmethylated CG dinucleotides are common in bacterial DNA but rare in mammalian DNA, our results indicate that exposure to bacterial DNA during infection may contribute to arthritis induction by amplifying the innate immune response.
Neural stem and progenitor cells in nestin‐GFP transgenic mice
Authors: Mignone John L. , Kukekov Valery , Chiang Ann‐Shyn , Steindler Dennis , Enikolopov Grigori
Published: January 2004

Neural stem cells generate a wide spectrum of cell types in developing and adult nervous systems. These cells are marked by expression of the intermediate filament nestin. We used the regulatory elements of the nestin gene to generate transgenic mice in which neural stem cells of the embryonic and adult brain are marked by the expression of green fluorescent protein (GFP). We used these animals as a reporter line for studying neural stem and progenitor cells in the developing and adult nervous systems. In these nestin‐GFP animals, we found that GFP‐positive cells reflect the distribution of nestin‐positive cells and accurately mark the neurogenic areas of the adult brain. Nestin‐GFP cells can be isolated with high purity by using fluorescent‐activated cell sorting and can generate multipotential neurospheres. In the adult brain, nestin‐GFP cells are ∼1,400‐fold more efficient in generating neurospheres than are GFP‐negative cells and, despite their small number, give rise to 70 times more neurospheres than does the GFP‐negative population. We characterized the expression of a panel of differentiation markers in GFP‐positive cells in the nestin‐GFP transgenics and found that these cells can be divided into two groups based on the strength of their GFP signal: GFP‐bright cells express glial fibrillary acidic protein (GFAP) but not βIII‐tubulin, whereas GFP‐dim cells express βIII‐tubulin but not GFAP. These two classes of cells represent distinct classes of neuronal precursors in the adult mammalian brain, and may reflect different stages of neuronal differentiation. We also found unusual features of nestin‐GFP–positive cells in the subgranular cell layer of the dentate gyrus. Together, our results indicate that GFP‐positive cells in our transgenic animals accurately represent neural stem and progenitor cells and suggest that these nestin‐GFP–expressing cells encompass the majority of the neural stem cells in the adult brain. J. Comp. Neurol. 469:311–324, 2004. © 2004 Wiley‐Liss, Inc.
Neurogenesis and stereological morphometry of calretinin‐immunoreactive GABAergic interneurons of the neostriatum
Authors: Rymar Vladimir V. , Sasseville Rachel , Luk Kelvin C. , Sadikot Abbas F.
Published: January 2004

We determined the neurogenesis characteristics of a distinct subclass of rat striatum γ‐aminobutyric acidergic (GABAergic) interneurons expressing the calcium‐binding protein calretinin (CR). Timed‐pregnant rats were given an intraperitoneal injection of 5‐bromo‐2′‐deoxyuridine (BrdU), a marker of cell proliferation, on designated days between embryonic day 12 (E12) and E21. CR‐immunoreactive (‐IR) neurons and BrdU‐positive nuclei were labeled in the adult neostriatum by double immunohistochemistry, and the proportion of double‐labeled cells was quantified. CR‐IR interneurons of the neostriatum show maximum birth rates (>10% double labeling) between E14 and E17, with a peak at E15. CR‐IR interneurons occupying the lateral half of the neostriatum become postmitotic prior to medial neurons. In the precomissural neostriatum, the earliest‐born neurons occupy the lateral quadrants and the latest‐born neurons occupy the dorsomedial sector. No significant rostrocaudal neurogenesis gradient is observed. CR‐IR neurons make up 0.5% of the striatal population and are localized in both the patch and the matrix compartments. CR‐IR neurons of the patch compartment are born early (E13–15), with later‐born neurons (E16–18) populating mainly the matrix compartment. CR‐IR cells of the neostriatum are a distinct subclass of interneurons that are born at an intermediate time during striatal development and share common neurogenesis characteristics with other interneurons and projection neurons produced in the ventral telencephalon. J. Comp. Neurol. 469:325–339, 2004. © 2004 Wiley‐Liss, Inc.
Morphologic analysis and classification of ganglion cells of the chick retina by intracellular injection of lucifer yellow and retrograde labeling with DiI
Authors: Naito Jumpei , Chen Yaoxing
Published: January 2004

Retinal ganglion cells (RGCs) of chicks were labeled by using the techniques of intracellular filling with Lucifer Yellow and retrograde axonal labeling with carbocyanine dye (DiI). Labeled RGCs were morphologically analyzed and classified into four major groups: Group I cells (57.1%) with a small somal area (77.5 μm2 on average) and narrow dendritic field (17,160 μm2 on average), Group II cells (28%) with a middle‐sized somal area (186 μm2) and middle‐sized dendritic field (48,800 μm2), Group III cells (9.9%) with a middle‐sized somal area (203 μm2) and wide dendritic field (114,000 μm2), and Group IV cells (5%) with a large somal area (399 μm2) and wide dendritic field (117,000 μm2). Of the four groups, Groups I and II were further subdivided into two types, simple and complex, on the basis of dendritic arborization: Groups Is, Ic, and Groups IIs, IIc. However, Group III and IV showed either a simple or complex type, Group IIIs and Group IVc, respectively. The density of branching points of dendrites was approximately 10 times higher in the complex types (18,350, 6,190, and 3,520 points/mm2 in Group Ic, IIc, and IVc, respectively) than in the simple types (1,890, 640, and 480 points/mm2 in Group Is, IIs, and IIIs). The branching density of Group I cells was extremely high in the central zone. The chick inner plexiform layer was divided into eight sublayers by dendritic strata of RGCs and 26 stratification patterns were discriminated. The central and peripheral retinal zones were characterized by branching density of dendrites and composition of RGC groups, respectively. J. Comp. Neurol. 469:360–376, 2004. © 2004 Wiley‐Liss, Inc.
Cellular correlates of progressive hearing loss in 129S6/SvEv mice
Authors: Ohlemiller Kevin K. , Gagnon Patricia M.
Published: January 2004

Several strains of mice hear well initially but show progressive sensorineural hearing loss. Affected cochlear cell types include all those known to be affected in human age‐related hearing loss (ARHL), or presbycusis. Thus these mice have been offered as models of human ARHL. At present, however, few mouse ARHL models are sufficiently well described to serve as the basis for specific hypotheses about human ARHL. We examined 1‐month‐old and 15‐month‐old 129S6/SvEv (129S6) mice and compared them with BALB/cJ and CBA/J mice. Age‐related elevation of compound action potential thresholds was interpreted in the light of endocochlear potentials and changes in hair cells, afferent neurons, fibrocytes in spiral limbus and ligament, and supporting cells within the organ of Corti. Aging in 129S6 mice was associated with high‐frequency hearing loss. Four components of age‐related cochlear degeneration emerged from quantitative analyses, including 1) basal loss of outer hair cells; 2) basal loss of type IV fibrocytes in the spiral ligament; 3) apical loss of fibrocytes in spiral limbus, and 4) anomalies of supporting cells in the cochlear base. Although neuronal loss was not consistently found, two mice showed loss of afferent dendrites and cell bodies in the cochlear apex without inner hair cell loss. Despite multifaceted degeneration, hearing loss in 129S6 mice appears to be best explained by degenerative changes in outer hair cells and in the organ of Corti, conforming to human sensory ARHL. Age‐related changes in the apical spiral limbus may promote pathology of the medial organ of Corti and eventual loss of afferent neurons, with possible implications for human neural ARHL. J. Comp. Neurol. 469:377–390, 2004. © 2004 Wiley‐Liss, Inc.
Efferent connections of septal nuclei of the domestic chick (Gallus domesticus): An anterograde pathway tracing study with a bearing on functional circuits
Authors: Montagnese Catherine M. , Székely Andrea D. , Ádám Ágota , Csillag András
Published: January 2004

Small iontophoretic injections of the anterograde tracerPhaseolus vulgarisleucoagglutinin were placed in different subregions of the septum of domestic chicks. The main targets of septal projections comprised the ipsi‐ and contralateral septal nuclei, including the nucleus of the diagonal band, basal ganglia, including the ventral paleostriatum, lobus parolfactorius, nucleus accumbens, and olfactory tubercle, archistriatum, piriform cortex, and anterior neostriatum. Further diencephalic and mesencephalic septal projections were observed in the ipsilateral preoptic region, hypothalamus (the main regions of afferentation comprising the lateral hypothalamic nuclei, ventromedial, paraventricular and periventricular nuclei, and the mammillary region), dorsal thalamus, medial habenular and subhabenular nuclei, midbrain central gray, and ventral tegmental area. Contralateral projections were also encountered in the septal nuclei, ventral paleostriatum, periventricular and anteromedial hypothalamic nuclei, suprachiasmatic nucleus, and the lateral hypothalamic area. Avian septal efferents are largely similar to those of mammals, the main differences being a relatively modest hippocampal projection arising mainly from the nucleus of the diagonal band (as confirmed by a specific experiment with the retrograde pathway tracer True blue), the lack of interpeduncular projection, and a greater contingent of amygdalar efferents arising from the lateral septum rather than the nucleus of the diagonal band. This pattern of connectivity is likely to reflect an important role of the avian septal nuclei in the coordination of limbic circuits and the integration of a wide variety of information sources modulating the appropriate behavioral responses: attention and arousal level, memory formation, hormonally mediated behaviors, and their affective components (such as ingestive, reproductive, and parental behaviors), social interaction, locomotor modulation, and circadian rhythm. J. Comp. Neurol. 469:437–456, 2004. © 2004 Wiley‐Liss, Inc.
Inner retinal abnormalities in a mouse model of Leber's congenital amaurosis
Authors: Pignatelli Vincenzo , Cepko Constance Louise , Strettoi Enrica
Published: January 2004

Leber's congenital amaurosis (LCA) is the earliest and most severe form in the world of genetic retinal dystrophy causing blindness. An animal model of LCA was recently created in which the cone‐rod homeobox (crx) gene was disrupted using homologous recombination. Crx−/− mice display abnormal development of photoreceptors followed by their degeneration. We analyzed the morphology of inner retinal cells in crx−/− mice in order to evaluate the effects of abnormal photoreceptor development and death upon other retinal neurons. The identification of a time window during which inner retinal cells are still viable could be very important in view of the possibilities that photoreceptor transplantation or gene therapy might be used to restore vision in LCA. We used a combination of immunocytochemical and confocal microscopy techniques to screen the crx−/− inner retina and verify its morphological integrity after photoreceptor degeneration. We found significant morphological alterations in second‐order neurons in crx−/− animals. The appearance of mutant retinas after photoreceptor death is indistinguishable from that of the retinal degeneration (rd/rd) mouse, a different genetic model of a retinal disease characterized by photoreceptor degeneration. However, at early stages of photoreceptor degeneration the morphology of retinal cells in the crx−/− mutant is considerably well preserved. It is likely that different genetic mechanisms that cause abnormal photoreceptor development and/or degeneration lead to a common pathway that determines second‐order neuron modifications. The severity of modifications is linked to the timing of onset of the degeneration and appears to increase with time. J. Comp. Neurol. 469:351–359, 2004. © 2004 Wiley‐Liss, Inc.
Development of vimentin and glial fibrillary acidic protein immunoreactivities in the brain of gray mullet (Chelon labrosus), an advanced teleost
Authors: Arochena Mercedes , Anadón Ramón , Díaz‐Regueira Sofía M.
Published: January 2004

Previous studies in teleosts have revealed the presence of the intermediate filaments vimentin (Vim) and glial fibrillary acidic protein (GFAP) in glial cells of the spinal cord and/or some brain regions, but there is no comprehensive study of their distribution and developmental changes in fishes. Here, the distribution of Vim and GFAP immunoreactivities was studied in the brain of larvae, juveniles, and adults of an advanced teleost, the gray mullet (Chelon labrosus). A different sequence of appearance was observed for expression of these proteins: Vim levels decreased with age, whereas GFAP increased. In general, both immunoreactivities were expressed early in perikarya and endfeet of ependymocytes (tanycytes), whereas expression in radial processes appeared later. In large larvae, the similar expression patterns of Vim and GFAP suggest that some of these glial cells contain both proteins. Subependymal radial glia cells were observed mainly in the optic tectum, exhibiting Vim and GFAP immunoreactivity. The only immunoreactive cells with astrocyte‐like morphology were observed in the optic chiasm of the adult, and they were positive for both GFAP and Vim. The perivascular processes of glial cells showed a different distribution of Vim and GFAP during development and had a caudorostral sequence of appearance of immunoreactivities similar to that observed for ependymal and radial glia cells. Several circumventricular organs (the organon vasculosum hypothalami, saccus vasculosus, and area postrema) exhibited highly specialized Vim‐ and/or GFAP‐expressing glial cells. The glial cells of the midline septa of several brain regions were also Vim and/or GFAP immunoreactive. In the adult brain, tanycytes retain Vim expression in several brain regions. As in other vertebrates, the regions with Vim‐immunoreactive ventricular and midline glia may represent areas with the capability of plasticity and regeneration in adult brain. J. Comp. Neurol. 469:413–436, 2004. © 2004 Wiley‐Liss, Inc.
Medullary and spinal cord projections from cardiovascular responsive sites in the rostral ventromedial medulla
Authors: Babic Tanja , Ciriello John
Published: January 2004

The rostral ventromedial medulla (RVMM) is a sympathoexcitatory area. However, little is known about its efferent projections. In this study, biotinylated dextran amine (BDA) or Phaseolus vulgaris leucoagglutinin (PHA‐L) were used to investigate the medullary and spinal cord projections from pressor sites in RVMM. Initially, RVMM was systematically explored in urethane‐anesthetized rats using microinjection of L‐glutamate for sites that elicited increases in arterial pressure. A pressor area was identified that included the rostral magnocellular reticular and rostral lateral paragigantocellular reticular nuclei. In the second series of experiments, BDA or PHA‐L was iontophoretically injected into RVMM pressor sites. Anterograde labeling was observed throughout the brainstem and spinal cord, bilaterally, but with an ipsilateral predominance. Dense labeling was observed within the nucleus of the solitary tract (NTS); the greatest density of labeling was observed in the caudal dorsolateral, medial, and ventrolateral subnuclei. Additionally, light to moderately dense labeling was found within the nucleus substantia gelatinosus and commissural nucleus. In the nucleus ambiguus/ventrolateral medullary (Amb/VLM) region, the density of labeling was greatest in caudal regions. Within Amb, most of the labeling was localized to its external formation. Anterograde labeling was also found throughout the spinal cord. In the thoracolumbar segments, dense axonal labeling was observed within the dorsolateral funiculus. These labeled axons innervated the intermediolateral nucleus and the central autonomic area. Taken together, these data suggest that RVMM neurons elicit increases in sympathetic activity by likely providing a direct excitatory input to spinal sympathetic preganglionic neurons, and by a direct inhibitory input to medullary cardioinhibitory and depressor areas. J. Comp. Neurol. 469:391–412, 2004. © 2004 Wiley‐Liss, Inc.
Numerical solutions of fully non‐linear and highly dispersive Boussinesq equations in two horizontal dimensions
Authors: Fuhrman David R. , Bingham Harry B.
Published: January 2004

This paper investigates preconditioned iterative techniques for finite difference solutions of a high‐order Boussinesq method for modelling water waves in two horizontal dimensions. The Boussinesq method solves simultaneously for all three components of velocity at an arbitrary z‐level, removing any practical limitations based on the relative water depth. High‐order finite difference approximations are shown to be more efficient than low‐order approximations (for a given accuracy), despite the additional overhead. The resultant system of equations requires that a sparse, unsymmetric, and often ill‐conditioned matrix be solved at each stage evaluation within a simulation. Various preconditioning strategies are investigated, including full factorizations of the linearized matrix, ILU factorizations, a matrix‐free (Fourier space) method, and an approximate Schur complement approach. A detailed comparison of the methods is given for both rotational and irrotational formulations, and the strengths and limitations of each are discussed. Mesh‐independent convergence is demonstrated with many of the preconditioners for solutions of the irrotational formulation, and solutions using the Fourier space and approximate Schur complement preconditioners are shown to require an overall computational effort that scales linearly with problem size (for large problems). Calculations on a variable depth problem are also compared to experimental data, highlighting the accuracy of the model. Through combined physical and mathematical insight effective preconditioned iterative solutions are achieved for the full physical application range of the model. Copyright © 2004 John Wiley & Sons, Ltd.
Simulation of transient flow in pipelines for computer‐based operations monitoring
Authors: Emara‐Shabaik H. E. , Khulief Y. A. , Hussaini I.
Published: January 2004

Computer models can provide the basis for real‐time monitoring and control of fluid flow in pipelines. Problems of fluid flow in pipelines are mathematically represented by a non‐linear system of coupled partial differential equations. In this paper, several numerical techniques are evaluated with respect to their suitability for the purpose of real‐time monitoring of fluid flow in pipelines. The proposed techniques are evaluated in terms of the L1, the L2, and the L∞ error norms. Moreover, the developed simulators will be compared in terms of their speed of response and settling time which are essential factors for an effective real‐time monitoring scheme. Finally, the selected simulation scheme is further tested under assumed pipeline leak conditions. Copyright © 2004 John Wiley & Sons, Ltd.
Numerical simulations of a filament in a flowing soap film
Authors: Farnell D. J. J. , David T. , Barton D. C.
Published: January 2004

Experiments concerning the properties of soap films have recently been carried out and these systems have been proposed as experimental versions of theoretical two‐dimensional liquids. A silk filament introduced into a flowing soap film, was seen to demonstrate various stable modes, and these were, namely, a mode in which the filament oscillates and one in which the filament is stationary and aligns with the flow of the liquid. The system could be forced from the oscillatory mode into the non‐ oscillatory mode by varying the length of the filament. In this article we use numerical and computational techniques in order to simulate the strongly coupled behaviour of the filament and the fluid. Preliminary results are presented for the specific case in which the filament is seen to oscillate continuously for the duration of our simulation. We also find that the filament oscillations are strongly suppressed when we reduce the effective length of the filament. We believe that these results are reminiscent of the different oscillatory and non‐oscillatory modes observed in experiment. The numerical solutions show that, in contrast to experiment, vortices are created at the leading edge of the filament and are preferentially grown in the curvature of the filament and are eventually released from the trailing edge of the filament. In a similar manner to oscillating hydrofoils, it seems that the oscillating filaments are in a minimal energy state, extracting sufficient energy from the fluid to oscillate. In comparing numerical and experimental results it is possible that the soap film does have an effect on the fluid flow especially in the boundary layer where surface tension forces are large. Copyright © 2004 John Wiley & Sons, Ltd.
Numerical simulation on an interaction of a vortex street with an elliptical leading edge using an unstructured grid
Authors: Shin Sangmook , Kim Chan Ki , Bai Kwang June
Published: January 2004

An algorithm for a time accurate incompressible Navier–Stokes solver on an unstructured grid is presented. The algorithm uses a second order, three‐point, backward difference formula for the physical time marching. For each time step, a divergence free flow field is obtained based on an artificial compressibility method. An implicit method with a local time step is used to accelerate the convergence for the pseudotime iteration. To validate the code, an unsteady laminar flow over a circular cylinder at a Reynolds number of 200 is calculated. The results are compared with available experimental and numerical data and good agreements are achieved.

Using the developed unsteady code, an interaction of a Karman vortex street with an elliptical leading edge is simulated. The incident Karman vortex street is generated by a circular cylinder located upstream. A clustering to the path of the vortices is achieved easily due to flexibility of an unstructured grid. Details of the interaction mechanism are analysed by investigating evolutions of vortices. Characteristics of the interactions are compared for large‐ and small‐scale vortex streets. Different patterns of the interaction are observed for those two vortex streets and the observation is in agreement with experiment. Copyright © 2004 John Wiley & Sons, Ltd.
Glutamate transporter expression and function in human glial progenitors
Authors: Maragakis Nicholas J. , Dietrich Joerg , Wong Victor , Xue Haipeng , Mayer‐Proschel Margot , Rao Mahendra S. , Rothstein Jeffrey D.
Published: January 2004

Glutamate is the major neurotransmitter of the brain, whose extracellular levels are tightly controlled by glutamate transporters. Five glutamate transporters in the human brain (EAAT1–5) are present on both astroglia and neurons. We characterize the profile of three different human astroglial progenitors in vitro: human glial restricted precursors (HGRP), human astrocyte precursors (HAPC), and early‐differentiated astrocytes. EAAT 1, EAAT3, and EAAT4 are all expressed in GRPs with a subsequent upregulation of EAAT1 following differentiation of GRPs into GRP‐derived astrocytes in the presence of bone morphogenic protein (BMP‐4). This corresponds to a significant increase in the glutamate transport capacity of these cells. EAAT2, the transporter responsible for the bulk of glutamate transport in the adult brain, is not expressed as a full‐length protein, nor does it appear to have functional significance (as determined by the EAAT2 inhibitor dihydrokainate) in these precursors. A splice variant of EAAT2, termed EAAT2b, does appear to be present in low levels, however. EAAT3 and EAAT4 expression is reduced as glial maturation progresses both in astrocyte precursors and early‐differentiated astrocytes and is consistent with their role in adult tissues as primarily neuronal glutamate transporters. These human glial precursors offer several advantages as tools for understanding glial biology because they can be passaged extensively in the presence of mitogens, afford the potential to study the temporal changes in glutamate transporter expression in a tightly controlled fashion, and are cultured in the absence of neuronal coculture, allowing for the independent study of astroglial biology. © 2003 Wiley‐Liss, Inc.
Localization of neuregulin isoforms and erbB receptors in myelinating glial cells
Authors: Raabe Timothy D. , Deadwyler Gail , Varga Jonathan W. , Devries George H.
Published: January 2004

Neuregulins (NRGs) are growth factors present in neurons and glial cells of the central and peripheral nervous systems and play a role in the survival, proliferation, and differentiation of these cells. We now report the localization of the two major isoforms of NRG (α and β) and their receptors (erbB) in cultured Schwann cells and oligodendrocytes isolated from neonatal rat pups. Immunocytochemistry and Western blots for NRG and erbB receptors in defined subcellular fractions were utilized to assess cellular localization. Less differentiated oligodendrocytes contain both NRG isoforms in the cell bodies but not the processes, while only NRG‐1β was found in the nucleus. In contrast, more differentiated oligodendrocytes contained neither isoform in the nucleus while both isoforms were colocalized in the cytoplasm and cell processes. In Schwann cells, both NRG‐1β and NRG‐1α were colocalized in the cytoplasm and processes. The Schwann cell nucleus had weak immunoreactivity for both NRG‐1 isoforms, although NRG‐1β was predominant. ErbB2 and erbB3 receptors, which transduce the NRG‐1 signal in Schwann cells, were found throughout the cytoplasm and in the processes and were also localized in the cell nucleus. The nuclear localization of NRG‐1 isoforms and/or erbB receptors in both cell types was confirmed by Western blotting of nuclear and cytoplasmic extracts. Stimulation of Schwann cells with mitotic agents increased NRG‐1β expression in the nucleus and dramatically suppressed NRG‐1α expression throughout the cell. The functional implications of this differential localization in myelinating cells are discussed. © 2003 Wiley‐Liss, Inc.
Signaling through JAK2‐STAT5 pathway is essential for IL‐3‐induced activation of microglia
Authors: Bright John J. , Natarajan Chandramohan , Sriram Subramaniam , Muthian Gladson
Published: January 2004

Microglia, the resident macrophage of the brain, mediates immune and inflammatory responses in the central nervous system (CNS). Activation of microglia and secretion of inflammatory cytokines associate with the pathogenesis of CNS diseases, including multiple sclerosis (MS), Alzheimer's disease (AD), Parkinson's disease, prion disease, and AIDS dementia. Microbial pathogens, cytokines, chemokines, and costimulatory molecules are potent inducers of microglial activation in the CNS. Signaling through its receptor, IL‐3 induces the activation of JAK‐STAT and MAP kinase pathways in microglial cells. In this study, we found that in vitro treatment of EOC‐20 microglial cells with tyrphostin AG490 blocked IL‐3‐induced tyrosine phosphorylation of JAK2, STAT5A, and STAT5B signaling proteins. Stable transfection of EOC‐20 cells with a dominant negative JAK2 mutant also blocked IL‐3‐induced tyrosine phosphorylation of JAK2, STAT5A, and STAT5B in microglia. The blockade of JAK2‐STAT5 pathway resulted in a decrease in IL‐3‐induced proliferation and expression of CD40 and major histocompatibility complex class II molecules in microglia. These findings highlight the fact that JAK2‐STAT5 signaling pathway plays a critical role in mediating IL‐3‐induced activation of microglia. © 2003 Wiley‐Liss, Inc.
Microglial tau undergoes phosphorylation‐independent modification after ischemia
Authors: Uchihara Toshiki , Nakamura Ayako , Arai Tetsuaki , Ikeda Kenji , Tsuchiya Kuniaki
Published: January 2004

Tau2 is a phosphorylation‐independent antibody that immunolabels neurofibrillary tangles (NFTs) of Alzheimer type and microglia around ischemic foci on formalin‐fixed, paraffin‐embedded sections. We found that copresence of polyethyleneglycol‐p‐isooctylphenyl ether (Triton X‐100; TX) with tau2 abolished its immunoreactivity (IR) in these microglia but not its IR on NFTs. Tau2‐immunoreactive bands, exclusively retrieved in Tris‐soluble fraction of brain homogenates from ischemic foci, normal human and bovine brains, were of similar electrophoretic mobility, indicating that tau2 IR in these microglia is unrelated to hyperphosphorylation of tau. These tau2‐immunoreactive bands except those from bovine brain were abolished in the copresence of TX. This was not due to washing out of tau, because similar immunoreactive bands were detectable with another antitau antibody even under a higher concentration of TX and because washing after TX exposure restored similar tau2 IR both on immunohistochemisty and immunoblot. These findings are explained if tau, modified after ischemia, undergoes a reversible conformational change on TX exposure. Because conformation at Ser101 of bovine tau is crucial for its affinity to tau2, this Ser‐like conformation mimicked by its human counterpart Pro may represent pathological modification of tau shared by microglia around ischemic foci and NFTs. Relative resistance of tau2 epitope in NFTs to TX exposure suggests that tau woven into NFTs confers additional stability to this pathological modification on tau2 epitope. Susceptibility of tau2 epitope to TX, seen in these microglia, is shared with glial cytoplasmic inclusions and will show its conformational state to be different from that in NFTs. © 2003 Wiley‐Liss, Inc.
Dystrophic microglia in the aging human brain
Authors: Streit Wolfgang J. , Sammons Nicole W. , Kuhns Amanda J. , Sparks D. Larry
Published: January 2004

We have studied microglial morphology in the human cerebral cortex of two nondemented subjects using high‐resolution LN‐3 immunohistochemistry. Several abnormalities in microglial cytoplasmic structure, including deramification, spheroid formation, gnarling, and fragmentation of processes, were identified. These changes were determined to be different from the morphological changes that occur during microglial activation and they were designated collectively as microglial dystrophy. Quantitative evaluation of dystrophic changes in microglia revealed that these were much more prevalent in the older subject (68‐year‐old) than in the younger one (38‐year‐old). Thus, we conclude that microglial dystrophy is a sign of microglial cell senescence. We hypothesize that microglial senescence could be important for understanding age‐related declines in cognitive function. © 2003 Wiley‐Liss, Inc.
Cell size‐proliferation relationship in rat glioma cells
Authors: Rouzaire‐Dubois Béatrice , Malo Michel , Milandri Jean‐Baptiste , Dubois Jean‐Marc
Published: January 2004

The homeostasis of the central nervous system is highly controlled by glial cells and is dramatically altered in the case of glioma. In this respect, the complex connection between cell size and division is of particular importance and needs clarifying. In order to investigate this connection, cell number and volume were measured in C6 rat glioma cells under different experimental conditions, including continuous cell culture, Cl− channel blockade, and anisotonicity, and in the presence of an inhibitory conditioned medium collected from cell cultures or in a medium containing a low level of fetal calf serum. The rate of cell proliferation changed with cell volume in a bell‐shaped manner, so that it is optimal within a cell volume window and appears to be controlled by low and high cell size checkpoints. The cell size‐proliferation relationship can be defined by Boltzmann‐like equations, which may reflect the effects of macromolecular crowding on proteins controlling the cell cycle progression. Altogether, these observations indicate that glioma cell proliferation is controlled predominantly but not exclusively by cell size‐dependent mechanisms. © 2003 Wiley‐Liss, Inc.
CNS axons retain their competence for myelination throughout life
Authors: Setzu Anna , Ffrench‐Constant Charles , Franklin Robin J.M.
Published: January 2004

An important question relevant to developing remyelination therapies is whether axons that remain without myelin sheaths after an episode of demyelination retain myelination competence. To resolve this, we have developed a model of transplantation into the nerve fibre layer of the adult rat retina, where the axons are unmyelinated. In the adult, these axons can be myelinated by transplantation of both the oligodendrocyte progenitor cells (OPCs) and an OPC line (CG4). The extent of myelination achieved following transplantation of OPCs is the same in young adult recipients (2 months old) as that which occurs in old adult recipients (12–18 months old), indicating that there are no changes in axons remaining unmyelinated for many months that would prevent effective remyelination. This finding suggests that chronically demyelinated regions of axons such as those in seen in multiple sclerosis are likely to remain competent to be remyelinated. © 2003 Wiley‐Liss, Inc.