bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for a Universal Relationship Between Magnetization and Changes in the Local Structure
Authors: Downward L. , Bridges F. , Cao D. , Neumeier J. , Zhou L.
Published: September 2003

X-ray Absorption Fine Structure (XAFS) measurements of the colossal magnetoresistance (CMR) sample La 0.79 Ca 0.21 MnO 3 at high fields indicate a decrease in the width parameter of the pair distribution function, σ, as the applied magnetic field is increased for T near Tc. The change in σ2 from the disordered polaron state varies approximately exponentially with magnetization irrespective of whether the sample magnetization was achieved through a change in temperature or the application of an external magnetic field. This suggests a more universal relationship between local structure and the sample magnetization than was previously indicated.
Ferromagnetic/Superconducting All-Oxide Superlattices
Authors: Habermeier H.-U. , Cristiani G.
Published: September 2003

Superlattices consisting of ferromagnetic SrRuO 3 and superconducting YBa 2 Cu 3 O 7 [YBCO] layers of a thickness between 5 nm and 60 nm have been analyzed with respect to their magnetic [T mag ] as well superconducting [TC] ordering temperature. The reduction of both is compared with previous results obtained in YBCO / La 2/3 Ca 1/3 MnO 3 superlattices. Whereas the reduction of TC is comparable for both ferromagnetic materials the suppression of ferromagnetism is more pronounced in the case of the SrRuO 3-based superlattices. This result is discussed in terms of a competition of the order parameters giving rise to ferromagnetism and superconductivity and the role of interface roughness.
Merging Fractal Image Compression and Wavelet Transform Methods
Authors: van de Walle A.
Published: September 2003

Fractal image compression and wavelet transform methods can be combined into a single compression scheme by using an iterated function system to generate the wavelet coefficients.

The main advantage of this approach is to significantly reduce the tiling artifacts: operating in wavelet space allows range blocks to overlap without introducing redundant coding. Our scheme also permits reconstruction in a finite number of iterations and lets us relax convergence criteria. Moreover, wavelet coefficients provide a natural and efficient way to classify domain blocks in order to shorten compression times.

Conventional fractal compression can be seen as a particular case of our general algorithm if we choose the Haar wavelet decomposition. On the other hand, our algorithm gradually reduces to conventional wavelet compression techniques as more and more range blocks fail to be properly approximated by rescaled domain blocks.
Entropy Constrained Fractal Image Coding
Authors: Barthel Kai Uwe
Published: September 2003

In this paper we present an entropy constrained fractal coding scheme. In order to get high compression rates, previous fractal coders used hierarchical coding schemes with variable range block sizes. Our scheme uses constant range block sizes, but the complexity of the fractal transformations is adapted to the image contents. The entropy of the fractal code can be significantly reduced by introducing geometrical codebooks of variable size and a variable order luminance transformation. We propose a luminance transformation consisting of a unification of fractal and transform coding. With this transformation both inter- and intra- block redundancy of an image can be exploited to get higher coding gain. The coding results obtained with our new scheme are superior compared to conventional fractal and transform coding schemes.
Similarity Hashing: A Computer Vision Solution to the Inverse Problem of Linear Fractals
Authors: Hart John C. , Cochran Wayne O. , Flynn Patrick J.
Published: September 2003

The difficult task of finding a fractal representation of an input shape is called the inverse, problem of fractal geometry. Previous attempts at solving this problem have applied techniques from numerical minimization, heuristic search and image compression. The most appropriate domain from which to attack this problem is not numerical analysis nor signal processing, but model-based computer vision. Self-similar objects cause an existing computer vision algorithm called geometric hashing to malfunction. Similarity hashing capitalizes on this observation to not only detect a shape's morphological self-similarity but also find the parameters of its self-transformations.
Inventing the Formula of the Trees: A Solution of the Representation of Self Similar Objects
Authors: Hocevar Erwin , Kropatsch Walter G.
Published: September 2003

Iterated Function Systems (IFS) seem to be used best to represent objects in the nature, because many of them are self similar. An IFS is a set of affine and contractive transformations. The union (so-called collage) of the subimages generated by transforming the whole image produces the image again - the self similar attractor of these transformations, which can be described by a binary image. For a fast and compact representation of those images, it would be desirable to calculate the transformations (the IFS-Codes) directly from the image that means to solve the inverse IFS-Problem. The solution presented in this paper will directly use the features of the self similar image. Subsets of the entire image and the subimage to be calculated are identified by the computation of the set difference between the pixels of the original and a rotated copy. The rotation and the scale factor of the transformation can be computed by the mapping of this two subsets onto each other, if the translation part - the fixed point - is predefined. The calculation of the transformation has to be repeated for each subimage. It will be proved, that with this method the IFS-Codes can be calculated for not convex, undistorted, and self similar images as long as the fixed point is known. An efficient algorithm for the identification of these fixed points within the image is introduced. Different ways to achieve this solutions are presented. In the conclusion the class of images, which can be coded by this method is defined, the results are pointed out, the advantages resp. the disadvantages of the method are evaluated, and possible ways to extend the method are discussed.
An Adaptive Partition for Fractal Image Coding
Authors: Davoine Franck , Bertin Etienne , Chassery Jean-Marc
Published: September 2003

In this paper we present a flexible partitioning scheme for fractal image compression, based on the Delaunay triangles. The aim is to have the advantage of triangular blocks over squares, in terms of adaptivity to the image content. In a first step, the triangulation is computed so that the triangles are more densely distributed in regions containing interesting features such as corners and edges, or so that they tend to run along the strong edges in the image. In a second step we merge adjacent triangles into quadrilaterals, in order to decrease the number of blocks. Quadrilaterals permit a reduction of the number of local contractive affine transformations composing the fractal transform, and thus to increase the compression ratio, while preserving the visual quality of the decoded image.
Stent Implantation Activates Akt in the Vessel Wall
Authors: Zhou Rui-Hai , Lee Tzong-Shyuan , Tsou Tsui-Chun , Rannou François , Li Yi-Shuan , Chien Shu , Shyy John Y.-J.
Published: September 2003

Objective—

The long-term efficacy of stent implantation is affected by in-stent restenosis (ISR). Multiple factors can contribute to ISR, and the underlying mechanism remains elusive. We investigated the possible role of mechanical stretch and the associated molecular signaling in ISR.

Methods and Results—

Stent implantation in rat abdominal aortas induced neointima formation. Immunohistochemical studies revealed the activation of Akt in the media and neointima of the stented vessels. Western blotting showed increased phosphorylation of Akt at both Thr308 and Ser473 and phosphorylation of GSK-3β in the stented vessels. A stretch device applying static equibiaxial stretch on cultured vascular smooth muscle cells was used to delineate the molecular mechanism underlying the stretch activation of Akt. Static mechanical stretch induced the sustained activation of Akt and its upstream phosphoinositide 3-kinase (PI3K) and the phosphorylation of GSK-3β, its downstream effector in vascular smooth muscle cells. LY294002, a PI3K inhibitor, and N-acetylcysteine, a scavenger of reactive oxygen species, inhibited the stretch activation of Akt. Furthermore,
N
-acetylcysteine and wortmannin, another PI3K inhibitor, reduced the neointima formation after stent implantation.

Conclusions—

Mechanical stretch of the vascular wall during stent deployment may contribute to ISR by activating the Akt pathway.
Selective Targeting and Timing of Matrix Metalloproteinase Inhibition in Post-Myocardial Infarction Remodeling
Authors: Yarbrough William M. , Mukherjee Rupak , Escobar G. Patricia , Mingoia Joseph T. , Sample Jeffrey A. , Hendrick Jennifer W. , Dowdy Kathryn B. , McLean Julie E. , Lowry Abigail S. , O’Neill Timothy P. , Spinale Francis G.
Published: September 2003

Background—

A cause-and-effect relationship exists between matrix metalloproteinase (MMP) induction and left ventricular (LV) remodeling after myocardial infarction (MI). Whether broad-spectrum MMP inhibition is necessary and the timing at which MMP inhibition should be instituted after MI remain unclear. This study examined the effects of MMP-1 and MMP-7-sparing inhibition (sMMPi) on regional and global LV remodeling when instituted before or after MI.

Methods and Results—

Pigs instrumented with coronary snares and radiopaque markers within the area at risk were randomized to MI only (n=11) or sMMPi (PGE-530742, 10 mg/kg PO TID) begun 3 days before MI (n=11) or 3 days after MI (n=10). Eleven weight-matched noninstrumented pigs served as reference controls. At 10 days after MI, infarct size was similar between groups (47±3% of the area at risk). Marker area increased from baseline in the MI-only group (10±3%,
P
<0.05) but was unchanged with sMMPi. LV end-diastolic volume increased in the MI-only group (82±3 mL) compared with controls (56±3 mL,
P
<0.05) but was attenuated with pre-MI and post-MI sMMPi (69±3 and 69±4 mL, respectively,
P
<0.05). Collagen content increased in the infarct zone of the MI-only group (34±5%) compared with control (2±1%,
P
<0.05) but was reduced with pre-MI and post-MI sMMPi (24±1% and 23±2%,
P
<0.05). Collagen content increased in the border zone (12±2%) and decreased in the remote zone (3±1%) of the pre-MI sMMPi group compared with post-MI sMMPi values (7±1% and 5±1%,
P
<0.05).

Conclusions—

Inhibition of MMP-1 and −7 is not required to favorably influence LV remodeling after MI. Moreover, a temporal difference exists with respect to the timing of sMMPi and regional and global myocardial remodeling patterns after MI.
Mice With a Null Mutation in the NHE1 Na
+
-H
+
Exchanger Are Resistant to Cardiac Ischemia-Reperfusion Injury
Authors: Wang Yigang , Meyer Jamie W. , Ashraf Muhammad , Shull Gary E.
Published: September 2003

Pharmacological studies indicate that Na
+
-H
+
exchanger isoform 1 (NHE1) plays a central role in myocardial ischemia-reperfusion injury; however, confirmation by alternative methods is lacking. To address this issue, we examined the role of NHE1 in ischemia-reperfusion injury using gene-targeted NHE1-null mutant (
Nhe1
−/−
) mice.
Nhe1
−/−
and wild-type hearts were perfused in a Langendorff apparatus in both the absence and presence of the NHE1 inhibitor eniporide, subjected to 40 minutes of ischemia and 30 minutes of reperfusion, and the effects of genetic ablation or inhibition of NHE1 on hemodynamic, biochemical, and pathological changes were assessed. In the absence of eniporide, left ventricular developed pressure, end-diastolic pressure, and coronary flow were significantly less impaired in
Nhe1
−/−
hearts relative to wild-type hearts, and release of lactate dehydrogenase, morphological damage, and ATP depletion were also significantly less. In the presence of eniporide, however, wild-type hearts were significantly protected and there were no significant differences between the two genotypes with respect to cardiac performance, lactate dehydrogenase release, or morphological damage. Furthermore, the presence or absence of eniporide had no apparent effect on the degree of cardioprotection observed in
Nhe1
−/−
hearts. These data demonstrate that genetic ablation of NHE1 protects the heart against ischemia-reperfusion injury. In addition to providing direct evidence that confirms previous pharmacological studies indicating a role for NHE1 in ischemia-reperfusion injury, these results suggest that the long-term absence of NHE1 does not elicit major compensatory changes that might negate the cardioprotective effects of blocking its activity over the short-term.
AP-1 Is Involved in UTP-Induced Osteopontin Expression in Arterial Smooth Muscle Cells
Authors: Renault M.-A. , Jalvy S. , Belloc I. , Pasquet S. , Sena S. , Olive M. , Desgranges C. , Gadeau A.-P.
Published: September 2003

Osteopontin (OPN), an RGD-containing extracellular matrix protein, is associated with arterial smooth muscle cell (SMC) activation in vitro and in vivo. Many cytokines and growth factors involved in vessel wall remodeling induce OPN overexpression. Moreover, we recently demonstrated that the extracellular nucleotide UTP also induces OPN expression and that OPN is essential for UTP-mediated SMC migration. Thus, we set out to investigate the mechanisms of OPN expression. The aim of this study was to identify transcription factors involved in the regulation of OPN expression in SMCs. First, we explored the contribution of mRNA stabilization and transcription in the increase of UTP-induced OPN mRNA levels. We show that UTP induced OPN mRNA increases via both OPN mRNA stabilization and OPN promoter activation. Then, to identify transcription factors involved in UTP-induced OPN transcription, we located a promoter element activated by UTP within the rat OPN promoter using a gene reporter assay strategy. The −96 to +1 region mediated UTP-induced OPN overexpression (+276±60%). Sequence analysis of this region revealed a potential site for AP-1 located at −76. When this AP-1 site was deleted, UTP-induced activation of the −96 to +1 region was totally inhibited. Thus, this AP-1 (−76) site is involved in UTP-induced OPN transcription. A supershift assay revealed that both c-Fos and c-Jun bind to this AP-1 site. Finally, we demonstrate that angiotensin II and platelet-derived growth factor, two main factors involved in vessel wall pathology, also modulated OPN expression via AP-1 activation.
Thromboxane A
2
-Induced Inhibition of Voltage-Gated K
+
Channels and Pulmonary Vasoconstriction
Authors: Cogolludo Angel , Moreno Laura , Bosca Lisardo , Tamargo Juan , Perez-Vizcaino Francisco
Published: September 2003

Voltage-gated K
+
channels (K
V
) and thromboxane A
2
(TXA
2
) play critical roles in controlling pulmonary arterial tone under physiological and pathological conditions. We hypothesized that TXA
2
might inhibit K
V
channels, thereby establishing a link between these two major pathogenic pathways in pulmonary hypertension. The TXA
2
analogue U46619 inhibited
I
K(V)
(E
max
=56.1±3.9%, EC
50
=0.054±0.019 μmol/L) and depolarized pulmonary artery smooth muscle cells via activation of TP receptors. In isolated pulmonary arteries, U46619 simultaneously increased intracellular Ca
2+
concentration and contractile force, and these effects were inhibited by nifedipine or KCl (60 mmol/L). U46619-induced contractions were not altered by the inhibitors of tyrosine kinase genistein or Rho kinase Y-27632 but were prevented by the nonselective protein kinase C (PKC) inhibitors staurosporine and calphostin C. Furthermore, these responses were sensitive to Gö-6983 but insensitive to bisindolylmaleimide I and Gö-6976. Based on the specificity of these drugs, we suggested a role for an atypical PKC in U46619-induced effects. Thus, treatment with a PKCζ pseudosubstrate inhibitor markedly prevented the vasoconstriction, the inhibition of
I
K(V)
, and the depolarization induced by U46619. Western blots showed a transient translocation of PKCζ from the cytosolic to the particulate fraction on stimulation with U46619. These results indicate that TXA
2
inhibits
I
K(V)
, leading to depolarization, activation of L-type Ca
2+
channels, and vasoconstriction of rat pulmonary arteries. We propose PKCζ as a link between TP receptor activation and K
V
channel inhibition.
Do Anionic Phospholipids Serve as Cofactors or Second Messengers for the Regulation of Activity of Cloned ATP-Sensitive K
+
Channels?
Authors: Quinn Kathryn V. , Cui Yi , Giblin Jonathan P. , Clapp Lucie H. , Tinker Andrew
Published: September 2003

The regulation of ion channels by anionic phospholipids is currently very topical. An outstanding issue is whether phosphatidylinositol 4,5-diphosphate and related species act as true second messengers in signaling or behave in a manner analogous to an enzymatic cofactor. This question is especially pertinent regarding ATP-sensitive K
+
channels in smooth muscle, for which there is substantial literature supporting inhibitory regulation by hormones. In this study, we have examined regulation of the potential cloned equivalents of the smooth muscle ATP-sensitive K
+
channel (SUR2B/Kir6.1 and SUR2B/Kir6.2). We find that both can be inhibited via the G
q/11
-coupled muscarinic M3 receptor but that the pathways by which this occurs are different. Our data show that SUR2B/Kir6.1 is inhibited by protein kinase C and binds anionic phospholipids with high affinity, such that potential physiological fluctuations in their levels do not influence channel activity. In contrast, Kir6.2 is not regulated by protein kinase C but binds anionic phospholipids with low affinity. In this case, phosphatidylinositol 4,5-diphosphate and related species have the potential to act as second messengers in signaling. Thus, Kir6.1 and Kir6.2 are regulated by distinct inhibitory mechanisms.
Treatment of multiple myeloma
Authors: Barlogie Bart , Shaughnessy John , Tricot Guido , Jacobson Joth , Zangari Maurizio , Anaissie Elias , Walker Ron , Crowley John
Published: September 2003

Autologous peripheral blood stem cell (PBSC)–supported high-dose melphalan is now considered standard therapy for myeloma, at least for younger patients. The markedly reduced toxicity of allotransplants using nonmyeloablative regimens (mini-allotransplantations) may hold promise for more widely exploiting the well-documented graft-versus-myeloma (GVM) effect. New active drugs include immunomodulatory agents, such as thalidomide and CC-5013 (Revimid; Celgene, Warren, NJ), and the proteasome inhibitor, PS 341 (Velcade; Millenium, Cambridge, MA), all of which not only target myeloma cells directly but also exert an indirect effect by suppressing growth and survival signals elaborated by the bone marrow microenvironment's interaction with myeloma cells. Among the prognostic factors evaluated, cytogenetic abnormalities (CAs), which are present in one third of patients with newly diagnosed disease, identify a particularly poor prognosis subgroup with a median survival not exceeding 2 to 3 years. By contrast, in the absence of CAs, 4-year survival rates of 80% to 90% can be obtained with tandem autotransplantations. Fundamental and clinical research should, therefore, focus on the molecular and biologic mechanisms of treatment failure in the high-risk subgroup.
Inhibitory effect of imatinib on normal progenitor cells in vitro
Authors: Bartolovic Kerol , Balabanov Stefan , Hartmann Ulrike , Komor Martina , Boehmler Andreas M. , Bühring Hans-Jörg , Möhle Robert , Hoelzer Dieter , Kanz Lothar , Hofmann Wolf-Karsten , Brümmendorf Tim H.
Published: September 2003

Imatinib is a novel tyrosine kinase inhibitor used for the treatment of Philadelphia chromosome–positive leukemias and other malignancies. Side effects are mostly moderate; however, a dose-dependent hematologic toxicity affecting all hematopoietic lineages is observed clinically. The aim of this study was to investigate the effect of imatinib on normal hematopoietic stem and progenitor cells in vitro. A dose-dependent decrease in proliferation potential was found when CD34+ cells were expanded in serum-free medium supplemented with 6 growth factors and imatinib. Functionally, a decrease in colony-forming capacity was observed under increasing doses of imatinib. However, no such effect on more primitive cobblestone area–forming cells was detectable. Both withdrawal of stem cell factor from our expansion cultures or functional inhibition of c-kit led to a similar degree of inhibition of expansion, whereas the effect of imatinib was substantially greater at all dose levels tested. These data suggest a significant inhibitory effect of imatinib on normal CD34+ progenitor (but not stem) cells that is largely independent of c-kit signaling.
Distinctive response of naïve lymphocytes from cord blood to primary activation via TCR
Authors: Cantó Elisabet , Rodriguez-Sanchez Jose Luis , Vidal Silvia
Published: September 2003

Umbilical cord blood (UCB) is now being considered an alternative to bone marrow for restoring hematopoiesis after myeloablative therapy. The lower risk of acute and chronic graft-versus-host disease in patients who received UCB cells seems related to the nature of UCB–T cells. Phenotypically, UCB–CD3+ cells are mostly naive (CD45RA+) and represent a transitional population between thymocytes and adult T cells. We examined the immune reactivity of highly purified, negatively selected CD4+CD45RA+ cells by mimicking activation via T cell receptor (TCR). All experiments included the extensively characterized adult peripheral blood (APB) cells as reference. On the contrary to APB, naive UCB–CD4+ cells were able to proliferate with anti-CD3 stimulation alone. With addition of interleukin (IL)-2 or costimulatory signal, both populations reached similar proliferation. Forty-eight hours after anti-CD3 stimulation, CD4+CD45RA+ from UCB, but not APB, showed characteristic blastic morphology and significant expression of CD25 on the surface. A low concentration of IL-2 was detected at 24 h by anti-CD3-stimulated UCB CD4+CD45RA+, which rapidly disappeared. By 72 h after activation, CD4+CD45RA+ UCB cells showed extensive apoptosis, whereas CD4+CD45RA+ APB cells showed low levels of apoptosis. Using RNase protection assay, we observed that CD95L levels were significantly higher in naive CD4+ cells from UCB than from APB after activation. However, neutralizing Fas-Fc protein was unable to inhibit anti-CD3-induced apoptosis, suggesting that this was a CD95-independent mechanism. These results indicate that UCB–CD4+CD45RA+ cells are able to start proliferating as a result of early IL-2 production after TCR engagement alone, but probably, as a result of the consumption of this IL-2, they undergo cell death.
HIV-1 gp120 induces anergy in naive T lymphocytes through CD4-independent protein kinase-A-mediated signaling
Authors: Masci Anna Maria , Galgani Mario , Cassano Silvana , De Simone Salvatore , Gallo Adriana , De Rosa Veronica , Zappacosta Serafino , Racioppi Luigi
Published: September 2003

The ability of the envelope glycoprotein gp120 [human immunodeficiency virus (HIV) env] to induce intracellular signals is thought to contribute to HIV-1 pathogenesis. In the present study, we found that the exposure of CD4+ CD45RA+ naive T cells to HIVenv results in a long-lasting hyporesponsiveness to antigen stimulation. This phenomenon is not dependent on CD4-mediated signals and also can be generated by the exposure of naive T cell to soluble CD4-HIVenv complexes. The analysis of the proximal signaling reveals that HIVenv does not activate Lck as well as the mitogen-activated protein kinase intermediate cascade. Conversely, the envelope glycoprotein stimulates the cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) activity and induces the progressive accumulation of the phosphorylated form of the cAMP-responsive element binding. Of note, the ligation of CXCR4 by stromal cell-derived factor-1α but not the engagement of CD4 by monoclonal antibody stimulates the PKA activity and induces a long-lasting hyporesponsivity state in naive CD4+ lymphocytes. The pretreatment of lymphocytes with H89, a cell-permeable PKA inhibitor, prevents the induction of anergy. These findings reveal a novel mechanism by which HIVenv may modulate the processes of clonal expansion, homeostatic proliferation, and terminal differentiation of the naive T lymphocyte subset.
Calcium-Sensing Receptor Induces Messenger Ribonucleic Acid of Human Securin, Pituitary Tumor Transforming Gene, in Rat Testicular Cancer
Authors: Tfelt-Hansen Jacob , Schwarz Peter , Terwilliger Ernest F. , Brown Edward M. , Chattopadhyay Naibedya
Published: September 2003

Pituitary tumor transforming gene (PTTG), the human ortholog of securin, is an oncogene. Few normal tissues express PTTG, although in the testis, it is more abundantly expressed. In cancer, however, its wide expression has been directly correlated with the proliferation and angiogenesis, although very little is known about the overall regulation of the PTTG gene. In this study, we investigate the role of the calcium-sensing receptor (CaR), a G protein-coupled receptor (GPCR), in regulating PTTG in a widely used model of humoral hypercalcemia of malignancy, the rat H-500 Leydig cell testicular cancer. We show that extracellular calcium (Ca2+o) up-regulates PTTG mRNA. This up-regulation has a rapid onset, starting at 0.5 h, and remains up-regulated until 40 h. The up-regulation was also Ca2+o concentration dependent, with increases (mean ± se) of 4.22 ± 1.61-fold, 5.11 ± 1.11-fold, and 5.64 ± 1.92-fold at 5, 7.5, and 10 mm calcium, respectively, compared with 0.5 mm Ca2+o. This effect was abolished by overexpression of a dominant-negative CaR (R185Q), thereby confirming that the effect of high Ca2+o is CaR mediated. Another GPCR agonist, ADP, had no effect on PTTG expression. Because PTTG has been reported to induce angiogenesis, we investigated the effect of elevated Ca2+o on vascular endothelial growth factor (VEGF) expression. Indeed high calcium up-regulated VEGF mRNA by 1.59 ± 0.22-fold. In conclusion, we show for the first time that a GPCR, the CaR, stimulates the synthesis of PTTG mRNA in a nonmetastasizing model for humoral hypercalcemia of malignancy and, in the process, might induce angiogenesis via VEGF.
Inhibition of Prolactin (PRL)-Induced Proliferative Signals in Breast Cancer Cells by a Molecular Mimic of Phosphorylated PRL, S179D-PRL
Authors: Schroeder Matthew D. , Brockman Jennifer L. , Walker Ameae M. , Schuler Linda A.
Published: September 2003

Posttranslational modifications of prolactin (PRL), including phosphorylation, vary with physiologic state and alter biologic activity. In light of the growing evidence for a role for PRL in proliferation in mammary cancer, we examined the ability of a mimic of phosphorylated human PRL, S179D-PRL, to initiate signals to several pathways in mammary tumor cells alone and in combination with unmodified PRL. Unmodified PRL employed multiple pathways to increase cellular proliferation and cyclin D1 levels in PRL-deficient MCF-7 cells. S179D-PRL was a weak agonist compared with unmodified PRL with regard to cellular proliferation, cyclin D1 levels, and phosphorylation of signal transducer and activator of transcription 5 and ERKs. However, S179D-PRL was a potent antagonist of unmodified PRL to these endpoints. In contrast to the reduced levels of the long isoform of the PRL receptor observed in response to a 3-d incubation with unmodified PRL, S179D-PRL up-regulated expression of this isoform, 4-fold. These studies support the utility of this mutant as a PRL antagonist to proliferative signals in mammary epithelial cells, including a potential role in breast cancer therapeutics.
Peptide Purification, Complementary Deoxyribonucleic Acid (DNA) and Genomic DNA Cloning, and Functional Characterization of Ghrelin in Rainbow Trout
Authors: Kaiya Hiroyuki , Kojima Masayasu , Hosoda Hiroshi , Moriyama Shunsuke , Takahashi Akiyoshi , Kawauchi Hiroshi , Kangawa Kenji
Published: September 2003

We have identified ghrelin from the stomach of rainbow trout. Four isoforms of ghrelin peptide were isolated: the C-terminal amidated type of rainbow trout ghrelin (rt ghrelin) composed of 24 amino acids (GSSFLSPSQKPQVRQGKGKPPRV-amide) is a basic form; des-VRQ-rt ghrelin, which deleted three amino acids (V13R14Q15) from rt ghrelin; and further two types of rt ghrelin that retained the glycine residue at the C terminus, rt ghrelin-Gly, and des-VRQ-rt ghrelin-Gly. The third serine residue was modified by octanoic acid, decanoic acid, or the unsaturated form of those fatty acids. In agreement with the isolated peptides, two cDNAs of different lengths were isolated. The rt ghrelin gene has five exons and four introns, and two different mRNA molecules are predicted to be produced by alternative splicing of the gene. A high level of ghrelin mRNA expression was detected in the stomach, and moderate levels were detected in the brain, hypothalamus, and intestinal tracts. Des-VRQ-rt ghrelin stimulated the release of GH in the rat in vivo. Furthermore, des-VRQ-rt ghrelin stimulated the release of GH, but not the release of prolactin and somatolactin in rainbow trout in vivo and in vitro. These results indicate that ghrelin is a novel GH secretagogue in rainbow trout that may affect somatic growth or osmoregulation through GH. Because ghrelin is expressed in various tissues other than stomach, it may play important role(s) in cellular function as a local regulator.
5′ Exon replacement and repair by spliceosome-mediated RNA trans-splicing
Authors: MANSFIELD S. GARY , CLARK REBECCA HAWKINS , PUTTARAJU M. , KOLE JOLANTA , COHN JONATHAN A. , MITCHELL LLOYD G. , GARCIA-BLANCO MARIANO A.
Published: September 2003

Spliceosome-mediated RNA trans-splicing (SMaRT) has been used previously to reprogram mutant endogenous CFTR and factor VIII mRNAs in human epithelial cell and tissue models and knockout mice, respectively. Those studies used 3′ exon replacement (3′ER); a process in which the distal portion of RNA is reprogrammed. Here, we also show that the 5′ end of mRNA can be completely rewritten by 5′ER. For proof-of-concept, and to test whether 5′ER could generate functional CFTR, we generated a mutant minigene target containing CFTR exons 10–24 (ΔF508) and a mini-intron 10, and a pretrans-splicing molecule (targeted to intron 10) containing CFTR exons 1–10 (+F508), and tested these two constructs in 293T cells for anion efflux transport. Cells cotransfected with target and PTM showed a consistent increase in anion efflux, but there was no response in control cells that received PTM or target alone. Using a LacZ reporter system to accurately quantify trans-splicing efficiency, we tested several unique PTM designs. These studies provided two important findings as follows: (1) efficient trans-splicing can be achieved by binding the PTM to different locations in the target, and (2) relatively few changes in PTM design can have a profound impact on trans-splicing activity. Tethering the PTM close to the target 3′ splice site (as opposed to the donor site) and inserting an intron in the PTM coding resulted in a 65-fold enhancement of LacZ activity. These studies demonstrate that (1) SMaRT can be used to reprogram the 5′ end of mRNA, and (2) efficiency can be improved substantially.
Combinatorial minimization and secondary structure determination of a nucleotide synthase ribozyme
Authors: CHAPPLE KELLY E. , BARTEL DAVID P. , UNRAU PETER J.
Published: September 2003

We previously isolated from random sequences ribozymes able to form a glycosidic linkage between a ribose sugar and 4-thiouracil in a reaction that mimics protein-catalyzed nucleotide synthesis. Here we report on two serial in vitro selection experiments that defined the core motif of one of the nucleotide synthase ribozymes and provided improved versions of this ribozyme. The first selection experiment started from a degenerate sequence pool based on the previously isolated sequence and used a selection-amplification protocol that allowed the sequence requirements at the 3′ terminus of the ribozyme to be interrogated. Comparing the active sequences identified in this experiment revealed the complicated secondary structure of the nucleotide synthase ribozyme. A second selection was then performed to remove nonessential sequence from the ribozyme. This selection started with a pool with variation introduced in both the sequence and the length of the nonconserved loops and joining regions. This pool was generated using a partial reblocking/deblocking strategy on a DNA synthesizer, allowing the combinatorial synthesis of both point deletions and point substitutions. The consensus ribozyme motif that emerged was an ~71 nt pseudoknot structure with five stems and two important joining segments. Comparative sequence analysis and a cross-linking experiment point to the probable location of nucleotide synthesis. The prototype isolate from the second selection was nearly 35 times more efficient than the initial isolate and at least 108 times more efficient than an upper limit of an as-yet undetectable uncatalyzed reaction, supporting the idea that RNA-catalyzed nucleotide synthesis might have been important in an RNA world.
B-cell and plasma-cell splicing differences: A potential role in regulated immunoglobulin RNA processing
Authors: BRUCE SHIRLEY R. , DINGLE R.W. CAMERON , PETERSON MARTHA L.
Published: September 2003

The immunoglobulin μ pre-mRNA is alternatively processed at its 3′ end by competing splice and cleavage-polyadenylation reactions to generate mRNAs encoding the membrane-associated or secreted forms of the IgM protein, respectively. The relative use of the competing processing pathways varies during B-lymphocyte development, and it has been established previously that cleavage-polyadenylation activity is higher in plasma cells, which secrete IgM, than in B cells, which produce membrane-associated IgM. To determine whether RNA-splicing activity varies during B-lymphocyte development to contribute to μ RNA-processing regulation, we first demonstrate that μ pre-mRNA processing is sensitive to artificial changes in the splice environment by coexpressing SR proteins with the μ gene. To explore differences between the splice environments of B cells and plasma cells, we analyzed the splicing patterns from two different chimeric non-Ig genes that can be alternatively spliced but have no competing cleavage-polyadenylation reaction. The ratio of intact exon splicing to cryptic splice site use from one chimeric gene differs between several B-cell and several plasma-cell lines. Also, the amount of spliced RNA is higher in B-cell than plasma-cell lines from a set of genes whose splicing is dependent on a functional exonic splice enhancer. Thus, there is clear difference between the B-cell and plasma-cell splicing environments. We propose that both general cleavage-polyadenylation and general splice activities are modulated during B-lymphocyte development to ensure proper regulation of the alternative μ RNA processing pathways.
Behavior of polyoxyethylene‐containing interpenetrating polymer networks and their LiCLO4 complexes as phase transfer catalysts and ionic conductors
Authors: Xie Hong‐Quan , Wang Gui‐Gui , Guo Jun‐Shi
Published: September 2003

Simultaneous grafted interpenetrating polymer networks (IPNs) based on [castor oil–poly(ethylene glycol) (PEG)] polyurethane and poly(alkyl methacrylate) were synthesized by simultaneously coupling castor oil and PEG with 2,4‐toluene diisocyanate and by radical polymerization of alkyl methacrylate with castor oil. The gel content of the IPNs is ∼96% in most cases. The IPNs were characterized by infrared spectroscopy. The effects of compositional variation of the IPNs on phase transfer catalytic efficiency and mechanical properties, and conductivity of the IPNs complexed with LiClO4 were also studied. The results show that the IPNs have good phase transfer catalytic ability in the Williamson reaction and exhibit a maximum conversion of potassium phenolate at 55% polyoxyethylene (PEO). The phase transfer catalytic ability of the IPN increases with molecular weight of PEG used in the IPN synthesis and with the length of alkyl groups of the grafts, but decreases with increasing crosslinking degree. The complex of the IPNs with LiClO4 exhibits good ionic conductivity at room temperature in the range 10−5–3 × 10−4 S/cm. This ionic conductivity decreases with increasing either the crosslinking degree or the molecular weight of PEG used, but increases with increasing PEO content. The more compatible are the grafts with PEO, the lower is the conductivity. Either butyl methacrylate or ethyl methacrylate is a good choice for the monomer in the synthesis of the IPNs for use as phase transfer catalysts and ion conducting materials. The IPNs showed high tensile strength in the range 10–20 MPa. The good mechanical properties of the IPNs favor their applications as a strong solid polymer electrolyte film and an easily recoverable phase transfer catalyst. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 830–836, 2003
Novel sorbents based on silica coated with polyethylenimine and crosslinked with poly(carboxylic acid): Preparation and characterization
Authors: Ghoul M. , Bacquet M. , Crini G. , Morcellet M.
Published: September 2003

Novel sorbents based on silica coated with polyethylenimine (SilPEI) and crosslinked with poly(carboxylic acid) were prepared and characterized. These sorbents are to be used for heavy metal decontamination of aqueous solutions and have to be prepared in easy and ecological ways. A part of the carboxylic moieties [from ethylenediaminetetraacetic acid (EDTA) or citric acid] reacts with some of the amine groups of polyethylenimine, initially coated onto the silica, whereas the other part remains free for further metal complexation. By changing various parameters (temperature, pH, presence or absence of an amide‐forming agent), the conditions to prepare the best sorbent—that is, the sorbent exhibiting both a high capacity for metal complexation and good stability in an acidic medium (conditions for metal desorption or stripping)—were defined. The sorbent was prepared by a reaction of 1 g of SilPEI and 1 g of EDTA in water at 0°C, pH 6, during 10 h, using 0.5 g of 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide hydrochloride as a coupling agent. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 799–805, 2003
Preparation and adsorption properties of resins containing amine, sulfonic acid, and carboxylic acid moieties
Authors: Rivas Bernabé L. , Castro Alejandro
Published: September 2003

Completely water‐insoluble resins containing amine, carboxylic acid, and sulfonic acid as ligand groups were synthesized by radical polymerization in solution. The yield was higher than 97%. The resins were characterized by FTIR spectroscopy and thermal analysis. The metal ion retention properties at different pH values were investigated by a batch method. Metal ions studied were: Cu(II), Cd(II), Zn(II), Hg(II), Pb(II), and Cr(III). The metal ion binding ability depended strongly on the pH. The retention properties were also tested under competitive conditions. Elution of the metal ion was investigated in acid medium at different concentrations. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 700–705, 2003
Temperature dependency of elastic moduli and internal dilational and shear frictions of polyetherimide
Authors: Fukuhara Mikio
Published: September 2003

To investigate the thermally activated structural change of polyetherimide, longitudinal and transverse wave velocity, six kinds of elastic parameters (Young's, shear, and bulk moduli, Lamé parameter, Poisson's ratio, and Debye temperature), and dilational and shear internal frictions were simultaneously measured over a temperature range 69–474 K, using the ultrasonic pulse method. All elastic moduli decreased with increasing temperature, suggesting a lowering of molecular bonding strength. From shear internal friction, the 190, 314, 371, 395, and 430 K peaks are interpreted as the γ‐ [derived from –C(O)– motion], β‐ (interplane slippage between benzene rings), β‐ (softening‐glass transition) peaks, and rotational vibration of main benzene rings and a local relaxation of the main chain, respectively. The abrupt increase peak from 449 K in dilational friction would be a low‐temperature side shoulder of the α–glass‐transition peak. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 759–764, 2003
“Orientation induced memory effect” in polyamides and the relationship to hydrogen bonding
Authors: Vasanthan N.
Published: September 2003

The influence of molecular orientation on the “memory effect” of polyamides was investigated by differential scanning calorimetry. Melt crystallization of undrawn and drawn polyamide 6 (N6) and polyamide 66 (N66) fibers showed no difference either in the rate of crystallization or crystallization temperature. We demonstrated that hydrogen bonding does not play a major role in melt crystallization kinetics of polyamides (N6 and N66), and the “memory effect” is only retained for polymers, including N6 and N66, because of insufficient time spent above the melting temperature. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 772–775, 2003
Binary blends of polyethers with fatty acids: A thermal characterization of the phase transitions
Authors: Pielichowski Krzysztof , Flejtuch Kinga
Published: September 2003

A series of binary blends of poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), and polytetrahydrofuran (PTHF), characterized by similar average molecular weights, with selected fatty acids (capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid) were prepared by melt mixing. Differential scanning calorimetry was applied to characterize the phase transitions of melting and crystallization, and a synergistic effect was found to occur for PEO/fatty acid blends, as evidenced by the values of the enthalpy of the phase transition. This effect was probably due to hydrogen bonding between PEO and the fatty (carboxylic) acids, which facilitated the formation of crystalline structures; an analysis of IR spectroscopy data showed a shift in the absorption bands of OH groups. The morphology development of the PEO/carboxylic acid blends, as observed with polarizing light microscopy, could be described as spherulitic growth with spontaneous selection of the lamellar thickness. The textures of the individual fibrils, consisting of stacks of several tens of lamellae corresponding to PPO and PTHF, were less regular than the texture of PEO and showed large macroscopic heterogeneity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 861–870, 2003
Thermal characteristics of interpenetrating polymer networks composed of poly(vinyl alcohol) and poly(N‐isopropylacrylamide)
Authors: Kim Seon Jeong , Park Sang Jun , Kim In Young , Chung Taek Dong , Kim Hee Chan , Kim Sun I.
Published: September 2003

Interpenetrating polymer networks (IPNs) composed of poly(vinyl alcohol) (PVA) and poly(N‐isopropylacrylamide) (PNIPAAm) were prepared by the sequential‐IPN method. The thermal characterization of the IPNs was investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dielectric analysis (DEA). Depression of the melting temperature (Tm) of the PVA segment in IPNs was observed with increasing PNIPAAm content using DSC. DEA was employed to ascertain the glass‐transition temperature (Tg) of IPNs. From the result of DEA, IPNs exhibited two Tg values, indicating the presence of phase separation in the IPNs. The thermal decomposition of IPNs was investigated using TGA and appeared at near 200°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 881–885, 2003
Expression of myeloid‐related proteins 8 and 14 in systemic‐onset juvenile rheumatoid arthritis
Authors: Frosch Michael , Vogl Thomas , Seeliger Stephan , Wulffraat Nico , Kuis Wietse , Viemann Dorothee , Foell Dirk , Sorg Clemens , Sunderkötter Cord , Roth Johannes
Published: September 2003

Objective

To analyze which cellular compartments are involved in the initial phase of systemic‐onset juvenile rheumatoid arthritis (JRA), and to investigate the role that myeloid‐related protein 8 (MRP‐8) and MRP‐14, two S‐100 proteins that are primarily expressed in phagocytes, play in the disease.

Methods

Skin biopsy samples obtained during patients' acute episodes of systemic‐onset JRA were analyzed by immunohistochemistry and in situ hybridization. Concentrations of MRP‐8/MRP‐14 in serum were determined by enzyme‐linked immunosorbent assay.

Results

By analyzing biopsy samples from cutaneous rashes during the initial phase of systemic‐onset JRA, we discovered infiltration of leukocytes expressing MRP‐8 and MRP‐14. Surprisingly, keratinocytes also showed de novo synthesis of these proinflammatory proteins, indicating activation of epithelial cells during systemic‐onset JRA. Serum concentrations of MRP‐8/MRP‐14 were 120‐fold higher compared with healthy controls and ∼12‐fold higher compared with patients with other inflammatory diseases. Concentrations of MRP‐8/MRP‐14 in patients with systemic‐onset JRA fell dramatically after remission was induced.

Conclusion

The exceptionally high serum levels of MRP‐8 and MRP‐14 in active systemic‐onset JRA make them prime candidates as markers for monitoring disease activity and response to treatment. Since MRP‐8/MRP‐14 exhibit direct effects on leukocyte adhesion to the vascular endothelium, their extensive expression in the epidermis indicates an active role for these S‐100 proteins in the initial phase of this systemic autoimmune disease.
Simultaneous, clonally identical T cell expansion in tonsil and synovium in a patient with rheumatoid arthritis and chronic tonsillitis
Authors: Kawano Mitsuhiro , Okada Kanae , Muramoto Hiroaki , Morishita Hajime , Omura Takayo , Inoue Ryo , Kitajima Susumu , Katano Kenichi , Koni Ichiro , Mabuchi Hiroshi , Yachie Akihiro
Published: September 2003

In some patients with rheumatoid arthritis (RA), the disease improves following tonsillectomy. We describe a 28‐year‐old woman with treatment‐resistant RA and chronic tonsillitis. Initially, her arthritis had been well controlled with methotrexate and corticosteroids, but the RA activity became difficult to control in spite of addition of bucillamine to the treatment regimen and repeated arthrocentesis with infusion of corticosteroid into her swollen joints. Closer examination revealed that the period of exacerbation of her chronic tonsillitis paralleled that of the systemic arthritis, and administration of antibiotics brought transient relief of the systemic symptoms. Her arthritis was ameliorated after successful tonsillectomy and synovectomy, with marked reduction of the serum rheumatoid factor concentration. Analysis of infiltrating T cell clones in tonsil and synovium using T cell receptor Vβ repertoire and third complementarity‐determining region size distribution analysis followed by nucleotide sequencing revealed common clonal T cell expansion in both tissues. This finding suggests the possible involvement of chronic focal infection in refractory RA.