bluuebunny/crossref_metadata_2025 huggingface dataset:
FINITE-TYPE KNOT INVARIANTS BASED ON THE BAND-PASS AND DOUBLED-DELTA MOVES
Authors: CONANT JAMES , MOSTOVOY JACOB , STANFORD TED
Published: April 2010

We study generalizations of finite-type knot invariants obtained by replacing the crossing change in the Vassiliev skein relation by some other local move, analyzing in detail the band-pass and doubled-delta moves. Using braid-theoretic techniques, we show that, for a large class of local moves, generalized Goussarov's n-equivalence classes of knots form groups under connected sum. (Similar results, but with a different approach, have been obtained before by Taniyama and Yasuhara.) It turns out that primitive band-pass finite-type invariants essentially coincide with standard primitive finite-type invariants, but things are more interesting for the doubled-delta move. The complete degree 0 doubled-delta invariant is the S-equivalence class of the knot. In this context, we generalize a result of Murakami and Ohtsuki to show that the only primitive Vassiliev invariants of S-equivalence taking values in an abelian group with no 2-torsion arise from the Alexander–Conway polynomial. We start analyzing degree one doubled-delta invariants by considering which Vassiliev invariants are of doubled-delta degree one, finding that there is exactly one such invariant in each odd Vassiliev degree, and at most one (which is ℤ2-valued) in each even Vassiliev degree. Analyzing higher doubled-delta degrees, we observe that the Euler degree n + 1 part of Garoufalidis and Kricker's rational lift of the Kontsevich integral is a doubled-delta degree 2n invariant.
SOME FINITENESS PROPERTIES FOR THE REIDEMEISTER–TURAEV TORSION OF THREE-MANIFOLDS
Authors: MASSUYEAU GWÉNAËL
Published: April 2010

We prove for the Reidemeister–Turaev torsion of closed oriented three-manifolds some finiteness properties in the sense of Goussarov and Habiro, that is, with respect to some cut-and-paste operations which preserve the homology type of the manifolds. In general, those properties require the manifolds to come equipped with an Euler structure and a homological parametrization.
Low anticoagulant heparin targets multiple sites of inflammation, suppresses heparin-induced thrombocytopenia, and inhibits interaction of RAGE with its ligands
Authors: Rao Narayanam V. , Argyle Brian , Xu Xiaoyu , Reynolds Paul R. , Walenga Jeanine M. , Prechel Margaret , Prestwich Glenn D. , MacArthur Robert B. , Walters Bradford B. , Hoidal John R. , Kennedy Thomas P.
Published: April 2010

While heparin has been used almost exclusively as a blood anticoagulant, important literature demonstrates that it also has broad anti-inflammatory activity. Herein, using low anti-coagulant 2- O,3- O-desulfated heparin (ODSH), we demonstrate that most of the anti-inflammatory pharmacology of heparin is unrelated to anticoagulant activity. ODSH has low affinity for anti-thrombin III, low anti-Xa, and anti-IIa anticoagulant activities and does not activate Hageman factor (factor XII). Unlike heparin, ODSH does not interact with heparin-platelet factor-4 antibodies present in patients with heparin-induced thrombocytopenia and even suppresses platelet activation in the presence of activating concentrations of heparin. Like heparin, ODSH inhibits complement activation, binding to the leukocyte adhesion molecule P-selectin, and the leukocyte cationic granular proteins azurocidin, human leukocyte elastase, and cathepsin G. In addition, ODSH and heparin disrupt Mac-1 (CD11b/CD18)-mediated leukocyte adhesion to the receptor for advanced glycation end products (RAGE) and inhibit ligation of RAGE by its many proinflammatory ligands, including the advanced glycation end-product carboxymethyl lysine-bovine serum albumin, the nuclear protein high mobility group box protein-1 (HMGB-1), and S100 calgranulins. In mice, ODSH is more effective than heparin in reducing selectin-mediated lung metastasis from melanoma and inhibits RAGE-mediated airway inflammation from intratracheal HMGB-1. In humans, 50% inhibitory concentrations of ODSH for these anti-inflammatory activities can be achieved in the blood without anticoagulation. These results demonstrate that the anticoagulant activity of heparin is distinct from its anti-inflammatory actions and indicate that 2- O and 3- O sulfate groups can be removed to reduce anticoagulant activity of heparin without impairing its anti-inflammatory pharmacology.
Differential regulation of cardiac glucose and fatty acid uptake by endosomal pH and actin filaments
Authors: Steinbusch Laura K. M. , Wijnen Wino , Schwenk Robert W. , Coumans Will A. , Hoebers Nicole T. H. , Ouwens D. Margriet , Coumans Will A. , Hoebers Nicole T. H. , Diamant Michaela , Bonen Arend , Glatz Jan F. C. , Luiken Joost J. F. P.
Published: April 2010

Insulin and contraction stimulate both cardiac glucose and long-chain fatty acid (LCFA) uptake via translocation of the substrate transporters GLUT4 and CD36, respectively, from intracellular compartments to the sarcolemma. Little is known about the role of vesicular trafficking elements in insulin- and contraction-stimulated glucose and LCFA uptake in the heart, especially whether certain trafficking elements are specifically involved in GLUT4 versus CD36 translocation. Therefore, we studied the role of coat proteins, actin- and microtubule-filaments and endosomal pH on glucose and LCFA uptake into primary cardiomyocytes under basal conditions and during stimulation with insulin or oligomycin (contraction-like AMP-activated protein kinase activator). Inhibition of coat protein targeting to Golgi/endosomes decreased insulin/oligomycin-stimulated glucose (−42%/−51%) and LCFA (−39%/−68%) uptake. Actin disruption decreased insulin/oligomycin-stimulated glucose uptake (−41%/−75%), while not affecting LCFA uptake. Microtubule disruption did not affect substrate uptake under any condition. Endosomal alkalinization increased basal sarcolemmal CD36 (2-fold), but not GLUT4, content, and concomitantly decreased basal intracellular membrane GLUT4 and CD36 content (−60% and −62%, respectively), indicating successful CD36 translocation and incomplete GLUT4 translocation. Additionally, endosomal alkalinization elevated basal LCFA uptake (1.4-fold) in a nonadditive manner to insulin/oligomycin, and decreased insulin/oligomycin-stimulated glucose uptake (−32%/−68%). In conclusion, 1) CD36 translocation, just like GLUT4 translocation, is a vesicle-mediated process depending on coat proteins, and 2) GLUT4 and CD36 trafficking are differentially dependent on endosomal pH and actin filaments. The latter conclusion suggests novel strategies to alter cardiac substrate preference as part of metabolic modulation therapy.
Lovastatin induces VSMC differentiation through inhibition of Rheb and mTOR
Authors: Wagner Robert J. , Martin Kathleen A. , Powell Richard J. , Rzucidlo Eva M.
Published: April 2010

It is becoming increasingly clear that cholesterol-independent effects of statins also contribute to the cardioprotective effects, but these mechanisms remain poorly understood. We investigated the effects of lovastatin on vascular smooth muscle phenotype. We have previously shown that mammalian target of rapamycin complex 1 (mTORC1) inhibition with rapamycin induces vascular smooth muscle cell (VSMC) differentiation. We found that lovastatin also inhibits mTORC1 signaling and that this inhibition is required for VSMC differentiation. Lovastatin inhibition of mTORC1 was farnesylation dependent, suggesting the farnesylated G protein Rheb (Ras homologue enriched in brain), a known upstream activator of mTORC1. Rheb overexpression induced mTORC1 activity and repressed contractile protein expression, but a farnesylation-deficient mutant (C18S) elicited the opposite effect. Rheb knockdown with small interfering RNA was also sufficient to inhibit mTORC1 and induce contractile protein expression, and it prevented statin-induced VSMC differentiation. Notably, mTORC1 activity was elevated in VSMC isolated from an intimal hyperplastic patient lesion compared with normal media, and lovastatin treatment inhibited mTORC1 activity in these cultures. Furthermore, lovastatin inhibited mTORC1 activity and prevented the downregulation of contractile protein expression in an ex vivo angioplasty model. In conclusion, these findings illustrate a mechanism for the cardioprotective effects of lovastatin through inhibition of Rheb and mTORC1 and promotion of a differentiated VSMC phenotype.
Effect of chronic contractile activity on mRNA stability in skeletal muscle
Authors: Lai Ruanne Y. J. , Ljubicic Vladimir , D'souza Donna , Hood David A.
Published: April 2010

Repeated bouts of exercise promote the biogenesis of mitochondria by multiple steps in the gene expression patterning. The role of mRNA stability in controlling the expression of mitochondrial proteins is relatively unexplored. To induce mitochondrial biogenesis, we chronically stimulated (10 Hz; 3 or 6 h/day) rat muscle for 7 days. Chronic contractile activity (CCA) increased the protein expression of PGC-1α, c-myc, and mitochondrial transcription factor A (Tfam) by 1.6-, 1.7- and 2.0-fold, respectively. To determine mRNA stability, we incubated total RNA with cytosolic extracts using an in vitro cell-free system. We found that the intrinsic mRNA half-lives ( t1/2) were variable within control muscle. Peroxisome proliferator-activated receptor-γ, coactivator-1α (PGC-1α) and Tfam mRNAs decayed more rapidly ( t1/2 = 22.7 and 31.4 min) than c-myc mRNA ( t1/2 = 99.7 min). Furthermore, CCA resulted in a differential response in degradation kinetics. After CCA, PGC-1α and Tfam mRNA half-lives decreased by 48% and 44%, respectively, whereas c-myc mRNA half-life was unchanged. CCA induced an elevation of both the cytosolic RNA-stabilizing human antigen R (HuR) and destabilizing AUF1 (total) by 2.4- and 1.8-fold, respectively. Increases in the p37AUF1, p40AUF1, and p45AUF1 isoforms were most evident. Thus these data indicate that CCA results in accelerated turnover rates of mRNAs encoding important mitochondrial biogenesis regulators in skeletal muscle. This adaptation is likely beneficial in permitting more rapid phenotypic plasticity in response to subsequent contractile activity.
Colonic inflammation alters Src kinase-dependent gating properties of single Ca2+ channels via tyrosine nitration
Authors: Ross Gracious R. , Kang Minho , Akbarali Hamid I.
Published: April 2010

Nitration of L-type calcium channels during colonic inflammation impairs phosphorylation by the tyrosine kinase, Src kinase. This results in decreased calcium currents. The purpose of this study was to determine the mechanism of the downregulation of Ca2+ currents in colonic inflammation. In whole cell voltage clamp of mouse single smooth muscle cells, long-duration depolarization produced noninactivating calcium currents that were significantly reduced by the Src kinase inhibitor, protein phosphatase 2 (PP2). Unitary Ba2+ currents were recorded upon repolarization from positive potentials in cell-attached patches of smooth muscle and hCav1.2b-transfected cells to assess the properties of the single channels attributed to the noninactivating open state. Repolarization to −40 mV from 0 mV resulted in single-channel events with conductance of ∼23 pS. The ensemble average of the tail currents from 1,000 sweeps was 337 ± 27 fA in control and 218 ± 49 fA ( P < 0.05) in inflamed cells. Neither open-probability nor open-time constants were significantly different between control and inflamed cells. However, the transition to the open state measured as channel availability was significantly reduced from 19 ± 3% to 6.4 ± 1%. Similarly, peak ensemble average current and channel availability were significantly reduced by PP2 and treatment with peroxynitrite in control cells. Mutation of COOH-terminal tyrosine residues in hCav1.2b Chinese hamster ovarian cells also decreased peak ensemble average tail currents and availability. The present findings suggest that the transition of Ca2+ channels to the noninactivating open state is Src kinase dependent. Tyrosine nitration prevents Src-mediated transitions, leading to decreased calcium currents.
Late chronic catechin antioxidant treatment is deleterious to the endothelial function in aging mice with established atherosclerosis
Authors: Gendron Marie-Ève , Théorêt Jean-François , Mamarbachi Aida M. , Drouin Annick , Nguyen Albert , Bolduc Virginie , Thorin-Trescases Nathalie , Merhi Yahye , Thorin Eric
Published: April 2010

Various antioxidants, including polyphenols, prevent the development of atherosclerosis in animal models, contrasting with the failure of antioxidants to provide benefits in patients with established atherosclerosis. We therefore tested in a mouse model the hypothesis that although catechin is atheroprotective in prevention, catechin brings no global vascular protection when initiated after established atherosclerosis, because aging associated with dyslipidemia has induced irreversible dysfunctions. To this end, LDLr−/−; hApoB+/+atherosclerotic (ATX, 9 mo old) and pre-ATX (3 mo old) male mice were treated with catechin (30 mg·kg−1·day−1) up to 12 mo of age. Vascular function and endothelium/leukocyte interactions were studied at 12 mo old. The renal artery endothelium-dependent dilations were impaired with age whereas adhesion of leukocytes onto the native aortic endothelium was increased ( P < 0.05). Aortic oxidative stress [reactive oxygen species (ROS)] increased ( P < 0.05) at 3 mo in ATX and at 12 mo in wild-type mice. Aorta mRNA expression of NADPH oxidase increased, whereas that of manganese superoxide dismutase decreased in 12-mo-old ATX mice only. In mice with established ATX, catechin (from 9 to 12 mo) reduced ( P < 0.05) by ∼60% ROS without affecting plaque burden. Notably, catechin worsened endothelial dysfunction and further increased leukocyte adhesion ( P < 0.05) in ATX mice. In contrast, the same catechin treatment reversed all age-related dysfunctions in wild-type mice. On the other hand, in pre-ATX mice treated for 9 mo with catechin, plaque burden was reduced by 64% ( P < 0.05) and all vascular markers were normalized to the 3-mo-old values. These results demonstrate that an antioxidant treatment is deleterious in mice with established atherosclerosis.
Regulation of reactive oxygen species by p53: implications for nitric oxide-mediated apoptosis
Authors: Popowich Daniel A. , Vavra Ashley K. , Walsh Christopher P. , Bhikhapurwala Hussein A. , Rossi Nicholas B. , Jiang Qun , Aalami Oliver O. , Kibbe Melina R.
Published: April 2010

Nitric oxide (NO) induces vascular smooth muscle cell (VSMC) apoptosis in part through activation of p53. Traditionally, p53 has been thought of as the gatekeeper, determining if a cell should undergo arrest and repair or apoptosis following exposure to DNA-damaging agents, depending on the severity of the damage. However, our laboratory previously demonstrated that NO induces apoptosis to a much greater extent in p53−/−compared with p53+/+VSMC. Increased reactive oxygen species (ROS) within VSMC has been shown to induce VSMC apoptosis, and recently it was found that the absence of, or lack of, functional p53 leads to increased ROS and oxidative stress within different cell types. This study investigated the differences in intracellular ROS levels between p53−/−and p53+/+VSMC and examined if these differences were responsible for the increased susceptibility to NO-induced apoptosis observed in p53−/−VSMC. We found that p53 actually protects VSMC from NO-induced apoptosis by increasing antioxidant protein expression [i.e., peroxiredoxin-3 (PRx-3)], thereby reducing ROS levels and cellular oxidative stress. We also observed that the NO-induced apoptosis in p53−/−VSMC was largely abrogated by pretreatment with catalase. Furthermore, when the antioxidant protein PRx-3 and its specific electron acceptor thioredoxin-2 were silenced within p53+/+VSMC with small-interfering RNA, not only did these cells exhibit greater ROS production, but they also exhibited increased NO-induced apoptosis similar to that observed in p53−/−VSMC. These findings suggest that ROS mediate NO-induced VSMC apoptosis and that p53 protects VSMC from NO-induced apoptosis by decreasing intracellular ROS. This research demonstrates that p53 has antioxidant functions in stressed cells and also suggests that p53 has antiapoptotic properties.
The bHLH transcription factor CHF1/Hey2 regulates susceptibility to apoptosis and heart failure after pressure overload
Authors: Liu Yonggang , Yu Man , Wu Ling , Chin Michael T.
Published: April 2010

Cardiac hypertrophy is a common response to hemodynamic stress in the heart and can progress to heart failure. To investigate whether the transcription factor cardiovascular basic helix-loop-helix factor 1/hairy/enhancer of split related with YRPW motif 2 (CHF1/Hey2) influences the development of cardiac hypertrophy and progression to heart failure under conditions of pressure overload, we performed aortic constriction on 12-wk-old male wild-type (WT) and heterozygous (HET) mice globally underexpressing CHF1/Hey2. After aortic banding, WT and HET mice showed increased cardiac hypertrophy as measured by gravimetric analysis, as expected. CHF1/Hey2 HET mice, however, demonstrated a greater increase in the ventricular weight-to-body weight ratio compared with WT mice ( P < 0.05). Echocardiographic measurements showed a significantly decreased ejection fraction compared with WT mice ( P < 0.05). Histological examination of Masson trichrome-stained heart tissue demonstrated extensive fibrosis in HET mice compared with WT mice. TUNEL staining demonstrated increased apoptosis in HET hearts ( P < 0.05). Exposure of cultured neonatal myocytes from WT and HET mice to H2O2 and tunicamycin, known inducers of apoptosis that work through different mechanisms, demonstrated significantly increased apoptosis in HET cells compared with WT cells ( P < 0.05). Expression of Bid, a downstream activator of the mitochondrial death pathway, was expressed in HET hearts at increased levels after aortic banding. Expression of GATA4, a transcriptional activator of cardiac hypertrophy, was also increased in HET hearts, as was phosphorylation of GATA4 at Ser105. Our findings demonstrate that CHF1/Hey2 expression levels influence hypertrophy and the progression to heart failure in response to pressure overload through modulation of apoptosis and GATA4 activity.
Luminal Ca2+content regulates intracellular Ca2+release in subepicardial myocytes of intact beating mouse hearts: effect of exogenous buffers
Authors: Kornyeyev Dmytro , Reyes Mariano , Escobar Ariel L.
Published: April 2010

Ca+-induced Ca2+release tightly controls the function of ventricular cardiac myocytes under normal and pathological conditions. Two major factors contributing to the regulation of Ca2+release are the cytosolic free Ca2+concentration and sarcoplasmic reticulum (SR) Ca2+content. We hypothesized that the amount of Ca2+released from the SR during each heart beat strongly defines the refractoriness of Ca2+release. To test this hypothesis, EGTA AM, a high-affinity, slow-association rate Ca2+chelator, was used as a tool to modify luminal SR Ca2+content. An analysis of the cytosolic and luminal SR Ca2+dynamics recorded from the epicardial layer of intact mouse hearts indicated that the presence of EGTA reduced the diastolic SR free Ca2+concentration and fraction of SR Ca2+depletion during each beat. In addition, this maneuver shortened the refractory period and accelerated the restitution of Ca2+release. As a consequence of the accelerated restitution, the frequency dependence of Ca2+alternans was significantly shifted toward higher heart rates, suggesting a role of luminal SR Ca2+in the genesis of this highly arrhythmogenic phenomenon. Thus, intra-SR Ca2+dynamics set the refractoriness and frequency dependence of Ca2+transients in subepicardial ventricular myocytes.
Therapeutic hypothermia cardioprotection via Akt- and nitric oxide-mediated attenuation of mitochondrial oxidants
Authors: Shao Zuo-Hui , Sharp Willard W. , Wojcik Kimberly R. , Li Chang-Qing , Han Mei , Chang Wei-Tien , Ramachandran Srinivasan , Li Jing , Hamann Kimm J. , Vanden Hoek Terry L.
Published: April 2010

Therapeutic hypothermia (TH) is a promising cardioprotective treatment for cardiac arrest and acute myocardial infarction, but its cytoprotective mechanisms remain unknown. In this study, we developed a murine cardiomyocyte model of ischemia-reperfusion injury to better determine the mechanisms of TH cardioprotection. We hypothesized that TH manipulates Akt, a survival kinase that mediates mitochondrial protection by modulating reactive oxygen species (ROS) and nitric oxide (NO) generation. Cardiomyocytes, isolated from 1- to 2-day-old C57BL6/J mice, were exposed to 90 min simulated ischemia and 3 h reperfusion. For TH, cells were cooled to 32°C during the last 20 min of ischemia and the first hour of reperfusion. Cell viability was evaluated by propidium iodide and lactate dehydrogenase release. ROS production was measured by 6-carboxy-2′,7′-dichlorodihydrofluorescein diacetate and mitochondrial membrane potential (ΔΨm) by 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazoly-carbocyanine iodide (JC-1). Phospho (p)-Akt (Thr308), p-Akt (Ser473), and phosphorylated heat shock protein 27 (p-HSP27) (Ser82) were analyzed by Western blot analysis. TH attenuated reperfusion ROS generation, increased NO, maintained ΔΨm, and decreased cell death [19.3 ± 3.3% ( n = 11) vs. 44.7 ± 2.7% ( n = 10), P < 0.001]. TH also increased p-Akt during ischemia before reperfusion. TH protection and attenuation of ROS were blocked by the inhibition of Akt and NO synthase but not by a cGMP inhibitor. HSP27, a regulator of Akt, also exhibited increased phosphorylation (Ser82) during ischemia with TH. We conclude that TH cardioprotection is mediated by enhanced Akt/HSP27 phosphorylation and enhanced NO generation, resulting in the attenuation of ROS generation and the maintenance of ΔΨm following ischemia-reperfusion.
Sympathetic nerves and the endothelium influence the vasoconstrictor effect of low concentrations of ouabain in pressurized small arteries
Authors: Raina Hema , Zhang Qingli , Rhee Albert Y. , Pallone Thomas L. , Wier W. Gil
Published: April 2010

We hypothesized that in salt-dependent forms of hypertension, endogenous ouabain acts on arterial smooth muscle to cause enhanced vasoconstriction. Here, we tested for the involvement of the arterial endothelium and perivascular sympathetic nerve terminals in ouabain-induced vasoconstriction. Segments of rat mesenteric or renal interlobar arteries were pressurized to 70 mmHg at 37°C and exposed to ouabain (10−11–10−7 M). Removal of the endothelium enhanced ouabain-induced vasoconstriction by as much as twofold (at an ouabain concentration of 10−9 M). A component of the ouabain-induced vasoconstriction is due to the enhanced spontaneous release of norepinephrine (NE) from nerve terminals in the arterial wall. The α1-adrenoceptor blocker prazosin (10−6 M) decreased ouabain-induced vasoconstrictions by as much as 50%. However, neither the contraction induced by sympathetic nerve activity (SNA) nor the NE release evoked by SNA (measured directly by carbon fiber amperometry) was increased by ouabain (<10−7 M). Nevertheless, the converse case was true: after brief bursts of SNA, vasoconstrictor responses to ouabain were transiently increased (1.75-fold). This effect may be mediated by neuropeptide Y and Y1 receptors on smooth muscle. In arteries lacking the endothelium and exposed to prazosin, ouabain (10−11 M and greater) caused vasoconstriction, indicating a direct effect of very “low” concentrations of ouabain on arterial smooth muscle. In conclusion, in intact arteries, the endothelium opposes ouabain (10−11–10−7M)-induced vasoconstriction, which is caused by both enhanced spontaneous NE release and direct effects on smooth muscle. Ouabain (<10−7M) does not enhance SNA-mediated contractions, but SNA enhances ouabain-induced contractions. The effects of endogenous ouabain may be accentuated in forms of hypertension that involve sympathetic nerve hyperactivity and/or endothelial dysfunction.
Cardiomyocyte contractile status is associated with differences in fibronectin and integrin interactions
Authors: Wu Xin , Sun Zhe , Foskett Andrea , Trzeciakowski Jerome P. , Meininger Gerald A. , Muthuchamy Mariappan
Published: April 2010

Integrins link the extracellular matrix (ECM) with the intracellular cytoskeleton and other cell adhesion-associated signaling proteins to function as mechanotransducers. However, direct quantitative measurements of the cardiomyocyte mechanical state and its relationship to the interactions between specific ECM proteins and integrins are lacking. The purpose of this study was to characterize the interactions between the ECM protein fibronectin (FN) and integrins in cardiomyocytes and to test the hypothesis that these interactions would vary during contraction and relaxation states in cardiomyocytes. Using atomic force microscopy, we quantified the unbinding force (adhesion force) and adhesion probability between integrins and FN and correlated these measurements with the contractile state as indexed by cell stiffness on freshly isolated mouse cardiomyocytes. Experiments were performed in normal physiological (control), high-K+ (tonically contracted), or low-Ca2+ (fully relaxed) solutions. Under control conditions, the initial peak of adhesion force between FN and myocyte α3β1- and/or α5β1-integrins was 39.6 ± 1.3 pN. The binding specificity between FN and α3β1- and α5β1-integrins was verified by using monoclonal antibodies against α3-, α5-, α3 + α5-, or β1-integrin subunits, which inhibited binding by 48%, 65%, 70%, or 75%, respectively. Cytochalasin D or 2,3-butanedione monoxime (BDM), to disrupt the actin cytoskeleton or block myofilament function, respectively, significantly decreased the cell stiffness; however, the adhesion force and binding probability were not altered. Tonic contraction with high-K+ solution increased total cell adhesion (1.2-fold) and cell stiffness (27.5-fold) compared with fully relaxed cells with low-Ca2+ solution. However, it could be partially prevented by high-K+ bath solution containing BDM, which suppresses contraction by inhibiting the actin-myosin interactions. Thus, our results demonstrate that integrin binding to FN is modulated by the contractile state of cardiac myocytes.
Direct inhibition of arginase attenuated airway allergic reactions and inflammation in a Dermatophagoides farinae-induced NC/Nga mouse model
Authors: Takahashi Noriko , Ogino Keiki , Takemoto Kei , Hamanishi Seiji , Wang Da-Hong , Takigawa Tomoko , Shibamori Masafumi , Ishiyama Hironobu , Fujikura Yoshihisa
Published: April 2010

The expression of arginase I has been a focus of research into the pathogenesis of experimental asthma, because arginase deprives nitric oxide synthase (NOS) of arginine and therefore participates in the attenuation of bronchodilators such as nitric oxide (NO). The present study used an intranasal mite-induced NC/Nga mouse model of asthma to investigate the contribution of arginase to the asthma pathogenesis, using an arginase inhibitor, Nω-hydroxy-nor-l-arginine (nor-NOHA). The treatment with nor-NOHA inhibited the increase in airway hyperresponsiveness (AHR) and the number of eosinophils in bronchoalveolar lavage fluid. NOx levels in the lung were elevated despite suppressed NOS2 mRNA expression. Accompanied by the attenuated activity of arginase, the expression of arginase I at both the mRNA and protein level was downregulated. The levels of mRNA for T helper 2 cytokines such as IL-4, IL-5, and IL-13, and for chemotactants such as eotaxin-1 and eotaxin-2, were reduced. Moreover, the accumulation of inflammatory cells and the ratio of goblet cells in the bronchiole were decreased. The study concluded that the depletion of NO caused by arginase contributes to AHR and inflammation, and direct administration of an arginase inhibitor to the airway may be beneficial and could be of use in treating asthma due to its anti-inflammatory and airway-relaxing effects, although it is not clear whether the anti-inflammatory effect is direct or indirect.
Regulated gene expression in cultured type II cells of adult human lung
Authors: Ballard Philip L. , Lee Jae W. , Fang Xiaohui , Chapin Cheryl , Allen Lennell , Segal Mark R. , Fischer Horst , Illek Beate , Gonzales Linda W. , Kolla Venkatadri , Matthay Michael A.
Published: April 2010

Alveolar type II cells have multiple functions, including surfactant production and fluid clearance, which are critical for lung function. Differentiation of type II cells occurs in cultured fetal lung epithelial cells treated with dexamethasone plus cAMP and isobutylmethylxanthine (DCI) and involves increased expression of 388 genes. In this study, type II cells of human adult lung were isolated at ∼95% purity, and gene expression was determined (Affymetrix) before and after culturing 5 days on collagen-coated dishes with or without DCI for the final 3 days. In freshly isolated cells, highly expressed genes included SFTPA/B/C, SCGB1A, IL8, CXCL2, and SFN in addition to ubiquitously expressed genes. Transcript abundance was correlated between fetal and adult cells ( r = 0.88), with a subset of 187 genes primarily related to inflammation and immunity that were expressed >10-fold higher in adult cells. During control culture, expression increased for 8.1% of expressed genes and decreased for ∼4% including 118 immune response and 10 surfactant-related genes. DCI treatment promoted lamellar body production and increased expression of ∼3% of probed genes by ≥1.5-fold; 40% of these were also induced in fetal cells. Highly induced genes (≥10-fold) included PGC, ZBTB16, DUOX1, PLUNC, CIT, and CRTAC1. Twenty-five induced genes, including six genes related to surfactant (SFTPA/B/C, PGC, CEBPD, and ADFP), also had decreased expression during control culture and thus are candidates for hormonal regulation in vivo. Our results further define the adult human type II cell molecular phenotype and demonstrate that a subset of genes remains hormone responsive in cultured adult cells.
Delayed neonatal lung macrophage differentiation in a mouse model of in utero ethanol exposure
Authors: Gauthier Theresa W. , Ping Xiao-Du , Gabelaia Levan , Brown Lou Ann S.
Published: April 2010

We have previously demonstrated that fetal ethanol exposure deranges the function and viability of the neonatal alveolar macrophage. Although altered differentiation of the alveolar macrophage contributes to pulmonary disease states within the adult lung, the effects of fetal ethanol exposure on the normal differentiation of interstitial to alveolar macrophage in the newborn lung are unknown. In the current study, using a mouse model of fetal ethanol exposure, we hypothesized that altered terminal differentiation of the neonatal interstitial to alveolar macrophage contributes to the observed cellular dysfunction in the ethanol-exposed newborn mouse. Control alveolar macrophage differentiation was characterized by increased expression of CD32/CD11b ( P ≤ 0.05) and increased in vitro phagocytosis of Staphylococcus aureus ( P ≤ 0.05) compared with interstitial macrophage. After in utero ethanol exposure, both alveolar and interstitial macrophage lacked the acquisition of CD32/CD11b ( P ≤ 0.05) and displayed impaired in vitro phagocytosis ( P ≤ 0.05). Ethanol significantly increased transforming growth factor-β1(TGF-β1) in the bronchoalveolar lavage fluid ( P ≤ 0.05), as well as in both interstitial and alveolar macrophages ( P ≤ 0.05). Oxidant stress contributed to the ethanol-induced changes on the interstitial and alveolar cells, since maternal supplementation with the glutathione precursor S-adenosylmethionine during ethanol ingestion normalized CD32/CD11b ( P ≤ 0.05), phagocytosis ( P ≤ 0.05), and TGF-β1in the bronchoalveolar lavage fluid and macrophages ( P ≤ 0.05). Contrary to our hypothesis, fetal ethanol exposure did not solely impair interstitial to alveolar macrophage differentiation. Rather, fetal ethanol exposure impaired both neonatal interstitial and alveolar macrophage phagocytic function and differentiation. Increased oxidant stress and elevated TGF-β1contributed to the impaired differentiation of both interstitial and alveolar macrophage.
Food demand and meal size in mice with single or combined disruption of melanocortin type 3 and 4 receptors
Authors: Atalayer Deniz , Robertson Kimberly L. , Haskell-Luevano Carrie , Andreasen Amy , Rowland Neil E.
Published: April 2010

Mice with homozygous genetic disruption of the melanocortin-4 receptor gene (MC4R−/−) are known to be hyperphagic and become obese, while those with disruption of the melanocortin-3 receptor gene (MC3R−/−) do not become markedly obese. The contribution of MC3R signaling in energy homeostasis remains little studied. In the present work, we compare MC3R−/− mice with wild-type (WT), MC4R−/−, and mice bearing disruption of both genes (double knockout, DKO) on select feeding and neuroanatomical dimensions. DKO mice were significantly more obese than MC4R−/−, whereas MC3R−/− weighed the same as WT. In a food demand protocol, DKO and MC4R−/− were hyperphagic at low unit costs for food, due primarily to increased meal size. However, at higher costs, their intake dropped below that of WT and MC3R−/−, indicating increased elasticity of food demand. To determine whether this higher elasticity was due to either the genotype or to the obese phenotype, the same food demand protocol was conducted in dietary obese C57BL6 mice. They showed similar elasticity to lean mice, suggesting that the effect is of genotypic origin. To assess whether the increased meal size in MC4R−/− and DKO might be due to reduced CCK signaling, we examined the acute anorectic effect of peripherally administered CCK and subsequently the induction of c-Fos immunoreactivity in select brain regions. The anorectic effect of CCK was comparable in MC4R−/− , DKO, and WT, but it was unexpectedly absent in MC3R−/−. CCK-induced c-Fos was lower in the paraventricular nucleus in MC3R−/− than the other genotypes. These data are discussed in terms of demand functions for food intake, MC receptors involved in feeding, and their relation to actions of gut hormones, such as CCK, and to obesity.
Transgenic overexpression of GLUT1 in mouse glomeruli produces renal disease resembling diabetic glomerulosclerosis
Authors: Wang Youli , Heilig Kathleen , Saunders Thomas , Minto Andrew , Deb Dilip K. , Chang Anthony , Brosius Frank , Monteiro Carmela , Heilig Charles W.
Published: April 2010

Previous work identified an important role for hyperglycemia in diabetic nephropathy (The Diabetes Control and Complications Trial Research Group. N Engl J Med 329: 977–986, 1993; UK Prospective Diabetes Study Group. Lancet 352: 837–853, 1998), and increased glomerular GLUT1 has been implicated. However, the roles of GLUT1 and intracellular glucose have not been determined. Here, we developed transgenic GLUT1-overexpressing mice (GT1S) to characterize the roles of GLUT1 and intracellular glucose in the development of glomerular disease without diabetes. GLUT1 was overexpressed in glomerular mesangial cells (MC) of C57BL6 mice, a line relatively resistant to diabetic nephropathy. Blood pressure, blood glucose, glomerular morphometry, matrix proteins, cell signaling, transcription factors, and selected growth factors were examined. Kidneys of GT1S mice overexpressed GLUT1 in glomerular MCs and small vessels, rather than renal tubules. GT1S mice were neither diabetic nor hypertensive. Glomerular GLUT1, glucose uptake, mean capillary diameter, and mean glomerular volume were all increased in the GT1S mice. Moderately severe glomerulosclerosis (GS) was established by 26 wk of age in GT1S mice, with increased glomerular type IV collagen and fibronectin. Modest increases in glomerular basement membrane thickness and albuminuria were detected with podocyte foot processes largely preserved, in the absence of podocyte GLUT1 overexpression. Activation of glomerular PKC, along with increased transforming growth factor-β1, VEGFR1, VEGFR2, and VEGF were all detected in glomeruli of GT1S mice, likely contributing to GS. The transcription factor NF-κB was also activated. Overexpression of glomerular GLUT1, mimicking the diabetic GLUT1 response, produced numerous features typical of diabetic glomerular disease, without diabetes or hypertension. This suggested GLUT1 may play an important role in the development of diabetic GS.
The effects of loading and estrogen on rat bone growth
Authors: Leppänen Olli V. , Sievänen Harri , Jokihaara Jarkko , Pajamäki Ilari , Kannus Pekka , Cooper David M. , Järvinen Teppo L. N.
Published: April 2010

This study evaluated the contributions of locomotive loading and estrogen to the development of diaphysis of rat femur. A randomized 2 × 2 study design was used. Altogether, 70 female Sprague-Dawley rats were used, of which 10 were euthanized at entry. Of the remaining rats, 16 served as controls, and the rest, 44, underwent a unilateral sciatic neurectomy. The effect of estrogen was removed by ovariectomizing one-half of the neurectomized rats. After 27 wk, the animals were euthanized, and the femora were excised. Irrespective of loading or estrogen, the femur length and mineral mass increased by 142 and 687%, respectively. Axial growth was not modulated either by locomotive loading or estrogen, but the loading resulted in direction-specific changes in the cross-sectional geometry. The estrogen-related gains were evident on the endocortical surface, while the loading-related gains occurred on the periosteal surface. The loading and estrogen were significantly associated with increased bone strength (21 and 15%, respectively) in the mediolateral direction, but not in the anteroposterior direction. Axial growth and accrual of bone mineral mass of the rat femur are largely independent of locomotive loading or estrogen, whereas these factors specifically account for the femur function, as either a mechanical lever or a mineral reservoir for reproduction, respectively.
An Approximation to Solution of Space and Time Fractional Telegraph Equations by He′s Variational Iteration Method
Authors: Sevimlican Ali
Published: April 2010

He′s variational iteration method (VIM) is used for solving space and time fractional telegraph equations. Numerical examples are presented in this paper. The obtained results show that VIM is effective and convenient.
UnusualMethylobacterium fujisawaenseInfection in a Patient withAcute LeukaemiaUndergoing Hematopoietic Stem Cell Transplantation: First Case Report
Authors: Fanci Rosa , Corti Giampaolo , Bartoloni Alessandro , Tortoli Enrico , Mariottini Alessandro , Pecile Patrizia
Published: April 2010

Microorganisms of the genusMethylobacteriumare facultative methylotrophic, gram-negative rods that are ubiquitous in nature and rarely cause human disease, mostly in subjects with preexisting causes of immune depression.Methylobacterium fujisawaense, first proposed as a new species in 1988, has never been reported as a bacterial agent of human infections so far. Here we describe a case ofM. fujisawaenseinfection in a relapsed acute leukaemia undergoing unrelated allogeneic hematopoietic stem cell transplantation. Molecular identification of anM. fujisawaensestrain was obtained from multiple mycobacterial blood cultures.
Study of Sweep and Induced Dihedral Effects in Subsonic Axial Flow Compressor Passages—Part II: Detailed Study of the Effects on Tip Leakage Phenomena
Authors: Ramakrishna P. V. , Govardhan M.
Published: April 2010

This article presents the detailed study of rotor tip leakage related phenomena in a low speed axial compressor rotor passages for three sweep configurations [Unswept (UNS), Tip Chordline Swept (TCS) and Axially Swept (AXS)]. Fifteen domains are numerically studied with 5 sweep configurations (0°, 20°TCS, 30°TCS, 20°AXS, and 30°AXS) and for 3 tip clearances (0.0%, 0.7% and 2.7% of the blade chord). Results were well validated with experimental data. Observations near the tip reveal that UNS rotor shows high sensitivity than the swept rotors in the blade pressure distribution with change in tip clearance. AXS rotor has high loading capability and less tip clearance effect on blade loading at the near stall mass flow. Downstream shift of the vortex rollup along the chord is observed with increased flow coefficient and increment in the tip gap height. In particular, the effect of flow coefficient is more predominant on this effect. Tip vortex-related flow blockage is less with the swept rotors. Among the rotors, the AXS rotor is found to incur low total pressure losses attributable to tip leakage. Effect of incidence is observed on the flow leakage direction.
There Goes the Neighborhood: Pathological Alterations in T-Tubule Morphology and Consequences for Cardiomyocyte Handling
Authors: Louch William E. , Sejersted Ole M. , Swift Fredrik
Published: April 2010

T-tubules are invaginations of the cardiomyocyte membrane into the cell interior which form a tortuous network. T-tubules provide proximity between the electrically excitable cell membrane and the sarcoplasmic reticulum, the main intracellular store. Tight coupling between the rapidly spreading action potential and release units in the SR membrane ensures synchronous release throughout the cardiomyocyte. This is a requirement for rapid and powerful contraction. In recent years, it has become clear that T-tubule structure and composition are altered in several pathological states which may importantly contribute to contractile defects in these conditions. In this review, we describe the “neighborhood” of proteins in the dyadic cleft which locally controls cardiomyocyte homeostasis and how alterations in T-tubule structure and composition may alter this neighborhood during heart failure, atrial fibrillation, and diabetic cardiomyopathy. Based on this evidence, we propose that T-tubules have the potential to serve as novel therapeutic targets.
Myosin Binding Protein-C Slow: An Intricate Subfamily of Proteins
Authors: Ackermann Maegen A. , Kontrogianni-Konstantopoulos Aikaterini
Published: April 2010

Myosin binding protein C (MyBP-C) consists of a family of thick filament associated proteins. Three isoforms of MyBP-C exist in striated muscles: cardiac, slow skeletal, and fast skeletal. To date, most studies have focused on the cardiac form, due to its direct involvement in the development of hypertrophic cardiomyopathy. Here we focus on the slow skeletal form, discuss past and current literature, and present evidence to support that: (i) MyBP-C slow comprises a subfamily of four proteins, resulting from complex alternative shuffling of the single MyBP-C slow gene, (ii) the four MyBP-C slow isoforms are expressed in variable amounts in different skeletal muscles, (iii) at least one MyBP-C slow isoform is preferentially found at the periphery ofM-bands and (iv) the MyBP-C slow subfamily may play important roles in the assembly and stabilization of sarcomericM- andA-bands and regulate the contractile properties of the actomyosin filaments.
Mediators of Inflammation in Polycystic Ovary Syndrome in Relation to Adiposity
Authors: Sathyapalan Thozhukat , Atkin Stephen L.
Published: April 2010

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of reproductive age group and is associated with a higher cardiovascular risk. Obesity, mainly visceral adiposity, is prevalent in patients with PCOS. Obesity is associated with low-grade inflammation and raised inflammatory cytokines, both of which are also described in patients with PCOS. In this paper, the potential relationships between fat distribution, adipocyte dysfunction and, altered inflammatory markers in patients with PCOS have been discussed.
Phase II Study of Biweekly Pemetrexed Plus Irinotecan as Second-Line Therapy for Metastatic Colorectal Cancer
Authors: Louvet C. , André T. , Gamelin E. , Hebbar M. , Mabro M. , Bennamoun M. , Rassam H. , de Gramont A.
Published: April 2010

Background. This open-label, single-arm, two-stage, Phase II study investigated the efficacy and safety of bi-weekly pemetrexed combined with irinotecan, in patients with metastatic colorectal cancer (mCRC), after first-line chemotherapy using FOLFOX regimen.Patients and methods. Patients received pemetrexed 400 mg/m²as a 10-minute intravenous infusion (with vitamin supplementation) followed by irinotecan 180 mg/m²as a 90-minute infusion on day 1 of a 14-day cycle, for a maximum of 12 cycles. The primary endpoint was response rate (RR;H0≤5%,Ha≥20%,α=0.05, power = 90%). Secondary endpoints were duration of response, progression-free survival (PFS), overall survival (OS), and toxicities.Results. Partial response was observed in six out of 44 patients enrolled in the study (RR = 13.6%). The median PFS and OS were 4.0 and 13.9 months, respectively. The most common grade 3-4 toxicities were fatigue: 20.5% of patients, neutropenia: 18.6%, diarrhea: 13.6%, elevated transaminases: 9.5%, anemia: 9.3%, and vomiting: 6.8%.Conclusion. Pemetrexed plus irinotecan administered every two weeks is an active and well-tolerated regimen in mCRC patients pretreated with FOLFOX regimen. However, this regimen does not seem to provide clinically relevant advantage over historical data of a classical FOLFIRI regimen.
Manganese Superoxide Dismutase Polymorphism and Risk of Gastric Lesions, and Its Effects on Chemoprevention in a Chinese Population
Authors: Tu Hua-kang , Pan Kai-feng , Zhang Yang , Li Wen-qing , Zhang Lian , Ma Jun-ling , Li Ji-you , You Wei-cheng
Published: April 2010

Background: Manganese superoxide dismutase is the primary antioxidant enzyme in the mitochondria and is involved in carcinogenesis. To investigate the association between MnSOD Val16Ala polymorphism and risk of advanced gastric lesions, and its effects on chemoprevention, a population-based study was conducted in Linqu, a high-risk area of gastric cancer in China.

Methods: Genotypes were determined by PCR-RFLP analysis in 3,355 subjects with the baseline histopathologic diagnosis in 1994, and 2,758 of these subjects received subsequent three interventions including vitamin supplementation for 7.3 years. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by unconditional logistic regression model.

Results: We found an increased risk of dysplasia in subjects with the Val/Ala+Ala/Ala genotype (OR, 1.31; 95% CI, 1.02-1.68) compared with the Val/Val genotype. Stratified analysis indicated that a significantly elevated risk of intestinal metaplasia (OR, 3.40; 95% CI, 2.64-4.38) or dysplasia (OR, 4.01; 95% CI, 2.79-5.74) was found in subjects carrying the Val/Ala+Ala/Ala genotype and Helicobacter pylori infection, and an interaction between this genotype and a high serum H. pylori IgG titer (>2.94) on the risk of dysplasia was observed (Pinteraction = 0.01). Furthermore, an elevated chance for regression of gastric lesions was observed in subjects with the Val/Ala+Ala/Ala genotype and high IgG titer in an intervention trial with vitamin supplementation (OR, 2.45; 95% CI, 1.37-4.38).

Conclusions: These findings suggest that Val16Ala polymorphism may play an important role in development of advanced gastric lesions and modify the effect of vitamin supplementation on the evolution of gastric lesions.

Impact: Val16Ala polymorphism is related to gastric cancer development. Cancer Epidemiol Biomarkers Prev; 19(4); 1089–97. ©2010 AACR.