bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of nonselective cation channels and PI3K on endothelin-1-induced PYK2 tyrosine phosphorylation in C6 glioma cells
Authors: Kawanabe Yoshifumi , Hashimoto Nobuo , Masaki Tomoh
Published: May 2013

We recently demonstrated that endothelin-1 (ET-1) activates two types of Ca2+-permeable nonselective cation channels (designated NSCC-1 and NSCC-2) in C6 glioma cells. In the present study, we investigated the effects of NSCCs on the ET-1-induced proline-rich tyrosine kinase 2 (PYK2) phosphorylation in C6 glioma cells. In addition, we examined the effects of phosphoinositide 3-kinase (PI3K) on the ET-1-induced NSCCs activation and PYK2 phosphorylation. The PI3K inhibitors wortmannin and LY-294002 inhibited ET-1-induced Ca2+ influx through NSCC-2 but not NSCC-1. On the other hand, addition of these inhibitors after stimulation with ET-1 failed to suppress Ca2+ influx through NSCC-2. PYK2 phosphorylation was abolished by blocking Ca2+ influx through NSCCs. The PI3K inhibitors blocked the NSCC-2-dependent part of ET-1-induced PYK2 phosphorylation. These results indicate that 1) NSCC-2 is stimulated by ET-1 via a PI3K-dependent cascade, whereas NSCC-1 is stimulated via a PI3K-independent cascade; 2) PI3K seems to be required for the activation of the Ca2+ entry, but not for its maintenance; 3) Ca2+ influx through NSCC-1 and NSCC-2 plays an essential role in ET-1-induced PYK2 phosphorylation; and 4) PI3K is involved in the ET-1-induced PYK2 phosphorylation that depends on the Ca2+ influx through NSCC-2.
Inhibition of sarcoplasmic reticulum Ca2+-ATPase by miconazole
Authors: Lax Antonio , Soler Fernando , Fernandez-Belda Francisco
Published: May 2013

The inhibition of sarcoplasmic reticulum Ca2+-ATPase activity by miconazole was dependent on the concentration of ATP and membrane protein. Half-maximal inhibition was observed at 12 μM miconazole when the ATP concentration was 50 μM and the membrane protein was 0.05 mg/ml. When ATP was 1 mM, a low micromolar concentration of miconazole activated the enzyme, whereas higher concentrations inhibited it. A qualitatively similar response was observed when Ca2+ transport was measured. Likewise, the half-maximal inhibition value was higher when the membrane concentration was raised. Phosphorylation studies carried out after sample preequilibration in different experimental settings shed light on key partial reactions such as Ca2+ binding and ATP phosphorylation. The miconazole effect on Ca2+-ATPase activity can be attributed to stabilization of the Ca2+-free enzyme conformation giving rise to a decrease in the rate of the Ca2+ binding transition. The phosphoryl transfer reaction was not affected by miconazole.
Na+/H+ exchangers in the human eccrine sweat duct
Authors: Granger D. , Marsolais M. , Burry J. , Laprade R.
Published: May 2013

Using an anti-NHE1 antibody, we demonstrate the presence of a Na+/H+ exchanger of isoform 1 (NHE1) in the human eccrine sweat duct. A strong staining was observed at the basolateral membrane of the outer cell layer (NHE1basal), at the junction between inner and outer cells layers (NHE1inter), and along the lateral membranes (NHE1later) of all cells of the duct. At the luminal membrane, no staining was demonstrated either for NHE1 or NHE3. To investigate Na+/H+ mediated proton transport, straight sweat duct portions were isolated and perfused in vitro under HCO3--free conditions. In the presence of basolateral 5-ethyl- N-isopropyl amiloride (EIPA), an acidification of 0.29 ± 0.03 pH units was observed, whereas no effect was observed with luminal EIPA. Bath sodium removal generated a stronger acidification (0.41 ± 0.09 pH units). Removal of luminal sodium (in the absence or presence of basolateral EIPA), or low luminal chloride, led to an alkalinization, presumably due to a decrease in intracellular sodium, strongly suggesting functional activity of NHE1inter. We therefore conclude that in the sweat duct, NHE1 plays a major role in intracellular pH regulation.
An ancient prevertebrate Na+-nucleoside cotransporter (hfCNT) from the Pacific hagfish (Eptatretus stouti)
Authors: Yao Sylvia Y. , Ng Amy M. , Loewen Shaun K. , Cass Carol E. , Baldwin Stephen A. , Young James D.
Published: May 2013

The human concentrative (Na+-linked) plasma membrane transport proteins hCNT1, hCNT2, and hCNT3 are pyrimidine nucleoside-selective (system cit), purine nucleoside-selective (system cif), or broadly selective for both pyrimidine and purine nucleosides (system cib), respectively. All have orthologs in other mammalian species and belong to a gene family (CNT) that has members in insects, nematodes, pathogenic yeast, and bacteria. Here, we report the cDNA cloning and functional characterization of a CNT family member from an ancient marine prevertebrate, the Pacific hagfish ( Eptatretus stouti). This Na+-nucleoside symporter, designated hfCNT, is the first transport protein to be characterized in detail in hagfish and is a 683-amino acid residue protein with 13 predicted transmembrane helical segments (TMs). hfCNT was 52, 50, and 57% identical in sequence to hCNT1, hCNT2, and hCNT3, respectively. Similarity to hCNT3 was particularly marked in the TM 4–13 region. When produced in Xenopus oocytes, hfCNT exhibited the transport properties of system cib, with uridine, thymidine, and inosine apparent K m values of 10–45 μM. The antiviral nucleoside drugs 3′-azido-3′-deoxythymidine, 2′,3′-dideoxycytidine, and 2′,3′-dideoxyinosine were also transported. Simultaneous measurement of uridine-evoked currents and radiolabeled uridine uptake under voltage-clamp conditions gave a Na+-to-uridine coupling ratio of 2:1 (cf. 2:1 for hCNT3 and 1:1 for hCNT1/2). The apparent K 50 value for Na+ activation was >100 mM. A 50:50 chimera between hfCNT and hCNT1 (TMs 7–13 of hfCNT replaced by those of hCNT1) exhibited hCNT1-like cation interactions, establishing that the structural determinants of cation stoichiometry and binding affinity were located within the carboxy-terminal half of the protein. The high degree of sequence similarity between hfCNT and hCNT3 may indicate functional constraints on the primary structure of the transporter and suggests that cib-type CNTs fulfill important physiological functions.
Functional characterization of human NBC4 as an electrogenic Na+-HCO 3 − cotransporter (NBCe2)
Authors: Virkki Leila V. , Wilson Darren A. , Vaughan-Jones Richard D. , Boron Walter F.
Published: May 2013

We have functionally characterized Na+-driven bicarbonate transporter (NBC)4, originally cloned from human heart by Pushkin et al. (Pushkin A, Abuladze N, Newman D, Lee I, Xu G, and Kurtz I. Biochem Biophys Acta 1493: 215–218, 2000). Of the four NBC4 variants currently present in GenBank, our own cloning efforts yielded only variant c. We expressed NBC4c (GenBank accession no. AF293337 ) in Xenopus laevis oocytes and assayed membrane potential ( V m) and pH regulatory function with microelectrodes. Exposing an NBC4c-expressing oocyte to a solution containing 5% CO2 and 33 mM HCO[Formula: see text]elicited a large hyperpolarization, indicating that the transporter is electrogenic. The initial CO2-induced decrease in intracellular pH (pHi) was followed by a slow recovery that was reversed by removing external Na+. Two-electrode voltage clamp of NBC4c-expressing oocytes revealed large HCO[Formula: see text]- and Na+-dependent currents. When we voltage clamped V m far from NBC4c's estimated reversal potential ( E rev), the pHirecovery rate increased substantially. Both the currents and pHi recovery were blocked by 200 μM 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS). We estimated the transporter's HCO[Formula: see text]:Na+ stoichiometry by measuring E rev at different extracellular Na+ concentration ([Na+]o) values. A plot of E rev against log[Na+]o was linear, with a slope of 54.8 mV/log[Na+]o. This observation, as well as the absolute E rev values, are consistent with a 2:1 stoichiometry. In conclusion, the behavior of NBC4c, which we propose to call NBCe2-c, is similar to that of NBCe1, the first electrogenic NBC.
Apical NHE isoforms differentially regulate butyrate-stimulated Na absorption in rat distal colon
Authors: Krishnan Selvi , Rajendran Vazhaikkurichi M. , Binder Henry J.
Published: May 2013

Bicarbonate and butyrate stimulate electroneutral Na absorption via apical membrane Na-H exchange (NHE) in rat distal colon. cAMP downregulates NHE-3 isoform and inhibits HCO3-dependent, but not butyrate-dependent, Na absorption. This study sought to determine whether 1) the apical membrane NHE-2 and NHE-3 isoforms differentially mediated HCO3- and butyrate-dependent Na absorption, and 2) cAMP had different effects on NHE-2 and NHE-3 isoforms. The effect of specific inhibitors of NHE-2 and NHE-3 isoforms (50 μM HOE 694 and 2 μM S3226, respectively) on unidirectional 22Na transepithelial fluxes performed across isolated mucosa from rat distal colon under voltage-clamp conditions was examined. HCO3 stimulation of Na absorption was inhibited by EIPA, a nonspecific inhibitor of all NHE isoforms, by S3226 and dibutyryl cAMP but not by HOE 694. In contrast, butyrate stimulation of Na absorption was not altered by dibutyryl cAMP and was not inhibited by HOE 694 in the absence of dibutyryl cAMP, but in the presence of dibutyryl cAMP was HOE694 sensitive. In contrast, S3226 inhibited butyrate-stimulated Na absorption in the absence of dibutyryl cAMP, but not in its presence. We conclude that 1) HCO3-stimulated Na absorption is mediated solely by NHE-3 isoform, whereas butyrate-stimulated Na absorption is mediated by either NHE-3 or NHE-2 isoform, and 2) dibutyryl cAMP selectively inhibits NHE-3 isoform but stimulates NHE-2 isoform. Dibutyryl cAMP does not inhibit butyrate-stimulated Na absorption as a result of its differential effects on NHE-2 and NHE-3 isoforms.
ET-1 stimulates ERK signaling pathway through sequential activation of PKC and Src in rat myometrial cells
Authors: Robin Philippe , Boulven Isaline , Desmyter Christine , Harbon Simone , Leiber Denis
Published: May 2013

In this study, we analyzed in rat myometrial cells the signaling pathways involved in the endothelin (ET)-1-induced extracellular signal-regulated kinase (ERK) activation required for the induction of DNA synthesis. We found that inhibition of protein kinase C (PKC) by Ro-31–8220 abolished ERK activation. Inhibition of phospholipase C (PLC) by U-73122 or of phosphoinositide (PI) 3-kinase by wortmannin partially reduced ERK activation. A similar partial inhibition was observed after treatment with pertussis toxin or PKC downregulation by phorbol ester treatment. The effect of wortmannin was additive with that produced by PKC downregulation but not with that due to pertussis toxin. These results suggest that both diacylglycerol-sensitive PKC, activated by PLC products, and diacylglycerol-insensitive PKC, possibly activated by a Gi-PI 3-kinase-dependent process, are involved in ET-1-induced ERK activation. These two pathways were found to be activated mainly through the ETA receptor subtype. ET-1 and phorbol ester stimulated Src activity in a PKC-dependent manner, both responses being abolished in the presence of Ro-31–8220. Inhibition of Src kinases by PP1 abrogated phorbol ester- and ET-1-induced ERK activation. Finally, ET-1 activated Ras in a PP1- and Ro-31–8220-sensitive manner. Altogether, our results indicate that ET-1 induces ERK activation in rat myometrial cells through the sequential stimulation of PKC, Src, and Ras.
Functional properties of four splice variants of a human pancreatic tandem-pore K+ channel, TALK-1
Authors: Han Jaehee , Kang Dawon , Kim Donghee
Published: May 2013

TALK-1a, originally isolated from human pancreas, is a member of the tandem-pore K+ channel family. We identified and characterized three novel splice variants of TALK-1 from human pancreas. The cDNAs of TALK-1b, TALK-1c, and TALK-1d encode putative proteins of 294, 322, and 262 amino acids, respectively. TALK-1a and TALK-1b possessed all four transmembrane segments, whereas TALK-1c and TALK-1d lacked the fourth transmembrane domain because of deletion of exon 5. Northern blot analysis showed that among the 15 tissues examined, TALK-1 was expressed mainly in the pancreas. TALK-1a and TALK-1b, but not TALK-1c and TALK-1d, could be functionally expressed in COS-7 cells. Like TALK-1a, TALK-1b was a K+-selective channel that was active at rest. Single-channel openings of TALK-1a and TALK-1b were extremely brief such that the mean open time was <0.2 ms. In symmetrical 150 mM KCl, the apparent single-channel conductances of TALK-1a and TALK-1b were 23 ± 3 and 21 ± 2 pS at –60 mV and 11 ± 2 and 10 ± 2 pS at +60 mV, respectively. TALK-1b whole cell current was inhibited 31% by 1 mM Ba2+ and 71% by 1 mM quinidine but was not affected by 1 mM tetraethylammonium, 1 mM Cs+, and 100 μM 4-aminopyridine. Similar to TALK-1a, TALK-1b was sensitive to changes in external pH. Acid conditions inhibited and alkaline conditions activated TALK-1a and TALK-1b, with a K1/2 at pH 7.16 and 7.21, respectively. These results indicate that at least two functional TALK-1 variants are present and may serve as background K+ currents in certain cells of the human pancreas.
Contribution of chloride channels to volume regulation of cortical astrocytes
Authors: Parkerson Kimberly A. , Sontheimer Harald
Published: May 2013

The objective of this study was to determine the relative contribution of Cl− channels to volume regulation of cultured rat cortical astrocytes after hypotonic cell swelling. Using a Coulter counter, we showed that cortical astrocytes regulate their cell volume by ∼60% within 45 min after hypotonic challenge. This volume regulation was supported when Cl− was replaced with Br−, NO[Formula: see text], methanesulfonate−, or acetate− but was inhibited when Cl− was replaced with isethionate− or gluconate−. Additionally, substitution of Cl− with I−completely blocked volume regulation. Volume regulation was unaffected by furosemide or bumetanide, blockers of KCl transport, but was inhibited by Cl− channel blockers, including 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB), 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS), and niflumic acid. Surprisingly, the combination of Cd2+ with NPPB, DIDS, or niflumic acid inhibited regulation to a greater extent than any of these drugs alone. Volume regulation did not differ among astrocytes cultured from different brain regions, as cerebellar and hippocampal astrocytes exhibited behavior identical to that of cortical astrocytes. These data suggest that Cl− flux through ion channels rather than transporters is essential for volume regulation of cultured astrocytes in response to hypotonic challenge.
Rac1, but not RhoA, signaling protects epithelial adherens junction assembly during ATP depletion
Authors: Gopalakrishnan Shobha , Dunn Kenneth W. , Marrs James A.
Published: May 2013

Rho family GTPase signaling regulates actin cytoskeleton and junctional complex assembly. Our previous work showed that RhoA signaling protects tight junctions from damage during ATP depletion. Here, we examined whether RhoA GTPase signaling protects adherens junction assembly during ATP depletion. Despite specific RhoA signaling- and ATP depletion-induced effects on adherens junction assembly, RhoA signaling did not alter adherens junction disassembly rates during ATP depletion. This shows that RhoA signaling specifically protects tight junctions from damage during ATP depletion. Rac1 GTPase signaling also regulates adherens junction assembly and therefore may regulate adherens junction assembly during ATP depletion. Indeed, we found that Rac1 signaling protects adherens junctions from damage during ATP depletion. Adherens junctions are regulated by various GTPases, including RhoA and Rac1, but adherens junctions are specifically protected by Rac1 signaling.
Presence of the M-type sPLA2 receptor on neutrophils and its role in elastase release and adhesion
Authors: Silliman Christopher C. , Moore Ernest E. , Zallen Garret , Gonzalez Ricardo , Johnson Jeffrey L. , Elzi David J. , Meng Xianzhong , Hanasaki Kohji , Ishizaki Jun , Arita Hitoshi , Ao Lihua , England Kelly M. , Banerjee Anirban
Published: May 2013

Secretory phospholipase A2 (sPLA2) produces lipids that stimulate polymorphonuclear neutrophils (PMNs). With the discovery of sPLA2 receptors (sPLA2-R), we hypothesize that sPLA2 stimulates PMNs through a receptor. Scatchard analysis was used to determine the presence of a sPLA2ligand. Lysates were probed with an antibody to the M-type sPLA2-R, and the immunoreactivity was localized. PMNs were treated with active and inactive (+EGTA) sPLA2 (1–100 units of enzyme activity/ml, types IA, IB, and IIA), and elastase release and PMN adhesion were measured. PMNs incubated with inactive, FITC-linked sPLA2-IB, but not sPLA2-IA, demonstrated the presence of a sPLA2-R with saturation at 2.77 fM and a K d of 167 pM. sPLA2-R immunoreactivity was present at 185 kDa and localized to the membrane. Inactive sPLA2-IB activated p38 MAPK, and p38 MAPK inhibition attenuated elastase release. Active sPLA2-IA caused elastase release, but inactive type IA did not. sPLA2-IB stimulated elastase release independent of activity; inactive sPLA2-IIA partially stimulated PMNs. sPLA2-IB and sPLA2-IIA caused PMN adhesion. We conclude that PMNs contain a membrane M-type sPLA2-R that activates p38 MAPK.
Induction of cyclooxygenase-2 by heat shock protein 60 in macrophages and endothelial cells
Authors: Billack Blase , Heck Diane E. , Mariano Thomas M. , Gardner Carol R. , Sur Runa , Laskin Debra L. , Laskin Jeffrey D.
Published: May 2013

The 60-kDa heat shock protein (HSP60), an endogenous ligand for the toll-like 4 receptor, is generated in response to inflammation, tissue injury, and/or stress and stimulates macrophages to produce cytotoxic and proinflammatory mediators including nitric oxide, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-12. In the present studies we report that HSP60 is an effective inducer of cyclooxygenase-2 (COX-2) in macrophages, as well as endothelial cells. In both cell types, the synthesis of COX-2 was coordinate with induction of nitric oxide synthase (NOS)-2 and with nitric oxide production. With the use of promoter constructs in transient transfection assays, optimal expression of COX-2 in macrophages was found to require nuclear factor (NF)-κB, the cAMP-response element (CRE), and NF-IL-6, but not the E-box. Mobility shift assays revealed that HSP60 induced NF-κB and CRE binding activity, while CCAAT/enhancer binding protein (C/EBP), which binds to NF-IL-6, was constitutively active in the cells. Both c-Jun and CRE binding protein (CREB) bound to the CRE, while C/EBP-β bound to NF-IL-6. These data indicate that NF-κB, C/EBP-β, c-Jun, and CREB are important in HSP60-induced expression of COX-2. The c-Jun-NH2-terminal kinase (JNK), p44/42 mitogen-activated protein (MAP) kinase [extracellular signal-regulated kinase 1/2 (ERK1/2)], and p38 MAP kinase were rapidly activated by HSP60 in the macrophages. PD-98059, an inhibitor of phosphorylation of ERK1/2, caused a marked inhibition of HSP60-induced COX-2 and NOS-2 expression. Unexpectedly, SB-203580, a p38 kinase antagonist, was found to block HSP60-induced expression of COX-2, but not NOS-2. These data indicate that both ERK1/2 kinase and p38 kinase play a role in regulating HSP60-induced expression of COX-2.
Na+/H+ exchanger 3 is in large complexes in the center of the apical surface of proximal tubule-derived OK cells
Authors: Akhter S. , Kovbasnjuk O. , Li X. , Cavet M. , Noel J. , Arpin M. , Hubbard A. L. , Donowitz M.
Published: May 2013

Cell biological approaches were used to examine the location and function of the brush border (BB) Na+/H+ exchanger NHE3 in the opossum kidney (OK) polarized renal proximal tubule cell line. NHE3 epitope tagged with the vesicular stomatitis virus glycoprotein epitope (NHE3V) was stably expressed and called OK-E3V cells. On the basis of cell surface biotinylation studies, these cells had 10–15% of total NHE3 on the BB. Intracellular NHE3V largely colocalized with Rab11 and to a lesser extent with EEA1. The BB location of NHE3V was examined by confocal microscopy relative to the lectins wheat germ aggluttinin (WGA) and phytohemagluttin E (PHA-E), as well as the B subunit of cholera toxin (CTB). The cells were pyramidal, and NHE3 was located in microvilli in the center of the apical surface. In contrast, PHA-E, WGA, and CTB were diffusely distributed on the BB. Detergent extraction showed that total NHE3V was largely soluble in Triton X-100, whereas virtually all surface NHE3V was insoluble. Sucrose density gradient centrifugation demonstrated that total NHE3V migrated at the same size as ∼400- and ∼900-kDa standards, whereas surface NHE3V was enriched in the ∼900-kDa form. Under basal conditions, NHE3 cycled between the cell surface and the recycling pathway through a phosphatidylinositol (PI) 3-kinase-dependent mechanism. Measurements of surface and intracellular pH were obtained by using FITC-WGA. Internalization of FITC-WGA occurred largely into the juxtanuclear compartment that contained Rab11 and NHE3V. pH values on the apical surface and in endosomes in the presence of the NHE3 blocker, S3226, were elevated, showing that NHE3 functioned to acidify both compartments. In conclusion, NHE3V in OK cells exists in distinct domains both in the center of the apical surface and in a juxtanuclear compartment. In the BB fraction, NHE3 is largely in the detergent-insoluble fraction in lipid rafts and/or in large heterogenous complexes ranging from ∼400 to ∼900 kDa.
Fish oil slows S phase progression and may cause upstream shift of DHFR replication origin ori-β in CHO cells
Authors: Istfan Nawfal W. , Chen Zhi-Yi , Rex Sybille
Published: May 2013

Fish oils (FOs) have been noted to reduce growth and proliferation of certain tumor cells, effects usually attributed to the content of polyunsaturated fatty acids of the n–3 family, which are thought to modulate cellular signaling pathways. We investigated the influence of FO on cell cycle kinetics of cultured Chinese hamster ovary cells. Exponentially growing cells were labeled with 5-bromo-2′-deoxyuridine (BrdU) and analyzed by flow cytometry after 5-day treatment with exogenous fat. Bivariate BrdU-DNA analysis indicated slower progression through S phase and thus longer S phase duration time in FO- but not corn oil-treated or control cells. We hypothesize that FO treatment might interfere with spatial/temporal organization of replication origins. Therefore, we mapped the well-characterized replication origin ori-β downstream of the dihydrofolate reductase gene with the nascent strand length assay. Three DNA marker segments with known positions relative to this origin were amplified by PCR. By quantitatively assessing DNA length of the fragments in all fractions containing these markers, the location of ori-β was established. In control or corn oil-treated cells, the location of ori-β was consistent with previous studies. However, in FO-treated cells, DNA replication appears to start from a new site located farther upstream from ori-β, suggesting a different replication initiation pattern. This study suggests novel mechanism(s) by which fats affect cell proliferation and DNA replication in mammalian cells.
Redox states of type 1 ryanodine receptor alter Ca2+ release channel response to modulators
Authors: Oba Toshiharu , Murayama Takashi , Ogawa Yasuo
Published: May 2013

The type 1 ryanodine receptor (RyR1) from rabbit skeletal muscle displayed two distinct degrees of response to cytoplasmic Ca2+ [high- and low-open probability ( P o) channels]. Here, we examined the effects of adenine nucleotides and caffeine on these channels and their modulations by sulfhydryl reagents. High- P o channels showed biphasic Ca2+ dependence and were activated by adenine nucleotides and caffeine. Unexpectedly, low- P o channels did not respond to either modulator. The addition of a reducing reagent, dithiothreitol, to the cis side converted the high- P o channel to a state similar to that of the low- P o channel. Treatment with p-chloromercuriphenylsulfonic acid (pCMPS) transformed low- P o channels to a high- P o channel-like state with stimulation by β,γ-methylene-ATP and caffeine. In experiments under redox control using glutathione buffers, shift of the cis potential toward the oxidative state activated the low- P ochannel, similar to that of the high- P o or the pCMPS-treated channel, whereas reductive changes inactivated the high- P o channel. Changes in transredox potential, in contrast, did not affect channel activity of either channel. In all experiments, channels with higher P o were stimulated to a great extent by modulators, but ones with lower P o were unresponsive. These results suggest that redox states of critical sulfhydryls located on the cytoplasmic side of the RyR1 may alter both gating properties of the channel and responsiveness to channel modulators.
Reduced vasorelaxation to estradiol and G-1 in aged female and adult male rats is associated with GPR30 downregulation
Authors: Lindsey Sarah H. , da Silva Ariel S. , Silva Mauro S. , Chappell Mark C.
Published: May 2013

Previously, we reported that chronic activation of the estrogen receptor GPR30 by its selective agonist G-1 decreases blood pressure in ovariectomized hypertensive mRen2.Lewis (mRen2) rats but not intact male littermates. Furthermore, G-1 relaxes female mesenteric resistance arteries via both endothelium-dependent and -independent mechanisms. Because of the lack of a blood pressure-lowering effect by G-1 in males and the potential influence of aging on estrogen receptor expression, we hypothesized that GPR30-dependent vasodilation and receptor expression are altered in males and aged females. Thus, we assessed the response to 17β-estradiol or G-1 in mesenteric arteries obtained from 15-wk-old normotensive Lewis and hypertensive mRen2 females and males as well as 52-wk-old Lewis females. Vasodilation to 17β-estradiol (E2) and G-1 was significantly attenuated in 15-wk-old Lewis and mRen2 males compared with age-matched females. Pretreatment of male vessels with the nitric oxide synthase inhibitor l-NAME had no significant effect on the estradiol or G-1 response. In aged females, E2 and G-1 vasorelaxation was also significantly blunted; however, l-NAME essentially abolished the response. Associated with the reduced vascular responses, GPR30 expression in mesenteric arteries was approximately 50% lower in males and aged females compared with young females. We conclude that alterations in GPR30 expression and signaling may contribute to vascular dysfunction in aging females and a greater blood pressure in hypertensive males.
Nonviral Gene Targeting at rDNA Locus of Human Mesenchymal Stem Cells
Authors: Hu Youjin , Liu Xionghao , Long Panpan , Xiao Di , Cun Jintao , Li Zhuo , Xue Jinfeng , Wu Yong , Luo Sha , Wu Lingqian , Liang Desheng
Published: May 2013

Background. Genetic modification, such as the addition of exogenous genes to the MSC genome, is crucial to their use as cellular vehicles. Due to the risks associated with viral vectors such as insertional mutagenesis, the safer nonviral vectors have drawn a great deal of attention.Methods. VEGF, bFGF, vitamin C, and insulin-transferrin-selenium-X were supplemented in the MSC culture medium. The cells’ proliferation and survival capacity was measured by MTT, determination of the cumulative number of cells, and a colony-forming efficiency assay. The plasmid pHr2-NL was constructed and nucleofected into MSCs. The recombinants were selected using G418 and characterized using PCR and Southern blotting.Results. BFGF is critical to MSC growth and it acted synergistically with vitamin C, VEGF, and ITS-X, causing the cells to expand significantly. The neomycin gene was targeted to the rDNA locus of human MSCs using a nonviral human ribosomal targeting vector. The recombinant MSCs retained multipotential differentiation capacity, typical levels of hMSC surface marker expression, and a normal karyotype, and none were tumorigenic in nude mice.Conclusions. Exogenous genes can be targeted to the rDNA locus of human MSCs while maintaining the characteristics of MSCs. This is the first nonviral gene targeting of hMSCs.
Dual-Dipole UHF RFID Tag Antenna with Quasi-Isotropic Patterns Based on Four-Axis Reflection Symmetry
Authors: Qin Chunfang , Mo Lingfei , Zhou Hongliang , Zhang Hongjian
Published: May 2013

In many RFID practical applications, it is required that reader can effectively read tags which are placed in radiation covering area randomly. In this paper, a passive UHF dual-dipole tag antenna with quasi-isotropic patterns is designed, which can reduce the sensibility of tag read-orientation in a long distance. Two dipoles with four-axis reflection symmetric structure are used, and the two arms of the dipole are bent to fill the space of the antenna. In this way, a quasi-isotropic tag is easier to be obtained. The test results show that the gain deviation of the proposed antenna was less than 3.25 dB, and the maximum reading range in different directions was from 6.9 m to 10.0 m, with better quasi-isotropic performance and reading range than other commercial tags.
A Numerical Method for Delayed Fractional-Order Differential Equations
Authors: Wang Zhen
Published: May 2013

A numerical method for nonlinear fractional-order differential equations with constant or time-varying delay is devised. The order here is an arbitrary positive real number, and the differential operator is with the Caputo definition. The general Adams-Bashforth-Moulton method combined with the linear interpolation method is employed to approximate the delayed fractional-order differential equations. Meanwhile, the detailed error analysis for this algorithm is given. In order to compare with the exact analytical solution, a numerical example is provided to illustrate the effectiveness of the proposed method.
Homoclinic Bifurcation and Chaos in a Noise-InducedΦ6Potential
Authors: Ge Gen , Zhu Zhi Wen , Xu Jia
Published: May 2013

The present paper focuses on the noise-induced chaos in aΦ6oscillator with nonlinear damping. Based on the stochastic Melnikov approach, simple zero points of the stochastic Melnikov integral theoretically mean the necessary condition causing noise-induced chaotic responses in the system. To quantify the noise-induced chaos, the Poincare maps and fractal basin boundaries are constructed to show how the system's motions change from a periodic way to chaos or from random motions to random chaos as the amplitude of the noise increases. Three cases are considered in simulating the system; that is, the system is excited only by the harmonic excitation, by both the harmonic and the Gaussian white noise excitations, or by both the bounded noise and the Gaussian white noise excitations. The results show that chaotic attractor is diffused by the noises. The larger the noise intensity is, the more diffused attractor it results in. And the boundary of the safe basin can also be fractal if the system is excited by the noises. The erosion of the safe basin can be aggravated when the frequency disturbing parameter of the bounded noise or the amplitude of the Gaussian white noise excitation is increased.
Ameliorating Effect of Various Fractions ofRumex hastatusRoots against Hepato- and Testicular Toxicity Caused by CCl4
Authors: Sahreen Sumaira , Khan Muhammad Rashid , Khan Rahmat Ali
Published: May 2013

Effect of methanolic extract ofRumex hastatusroots (MRR) and its derived fractions, n-hexane (HRR), ethyl acetate (ERR), chloroform (CRR), butanol (BRR), and aqueous extract (ARR), was studied against carbon tetrachloride (CCl4) induced hepato and testicular toxicity in rats. Intraperitoneal dose of 20 percent CCl4(0.5 ml/kg bw) was administered twice a week for eight weeks to a group of rats. Other groups were given CCl4and various fractions ofR. hastatusroots (200 mg/kg bw). CCl4treatment depleted glutathione contents and activities of antioxidant enzymes while increased the concentration of lipid peroxides (TBARS) along with corresponding DNA injuries and histopathological damages. Supplementation with various fractions ofR. hastatusroots (200 mg/kg body weight) attenuated the toxicity of CCl4in liver and testis tissues through improvement in the serological, enzymatic, and histological parameters towards the normal. Posttreatment ofR. hastatusroots (200 mg/kg body weight) also reversed the alteration in reproductive hormonal secretions and DNA damages in CCl4treated rats. The results clearly demonstrated thatR. hastatustreatment augments the antioxidants defense mechanism and provides the evidence that it may have a therapeutic role in free radical mediated diseases.
Psychoneuroimmunology-Based Stress Management during Adjuvant Chemotherapy for Early Breast Cancer
Authors: Robins Jo Lynne W. , McCain Nancy L. , Elswick R. K. , Walter Jeanne M. , Gray D. Patricia , Tuck Inez
Published: May 2013

Objective. In a randomized trial of women with early stage breast cancer undergoing adjuvant chemotherapy, two stress management interventions, tai chi training and spiritual growth groups, were compared to a usual care control group, to evaluate psychosocial functioning, quality of life (QOL), and biological markers thought to reflect cancer- and treatment-specific mechanisms.Method. The sample consisted of 145 women aged 27–75 years; 75% were Caucasian and 25% African American. A total of 109 participants completed the study, yielding a 75% retention rate. Grounded in a psychoneuroimmunology framework, the overarching hypothesis was that both interventions would reduce perceived stress, enhance QOL and psychosocial functioning, normalize levels of stress-related neuroendocrine mediators, and attenuate immunosuppression.Results. While interesting patterns were seen across the sample and over time, the interventions had no appreciable effects when delivered during the period of chemotherapy.Conclusions. Findings highlight the complex nature of biobehavioral interventions in relation to treatment trajectories and potential outcomes. Psychosocial interventions like these may lack sufficient power to overcome the psychosocial or physiological stress experiencedduring the chemotherapy treatment period. It may be that interventions requiring less activity and/or group attendance would have enhanced therapeutic effects, and more active interventions need to be tested prior to and following recovery from chemotherapy.
The P25 Ookinete Surface Proteins: Homology Modeling and Phylogenetic Relationships
Authors: Sharma Babita , Jaiswal Manoj Kumar
Published: May 2013

Sexual stages of Plasmodium such as zygote, ookinete, and young oocysts express 25 kDa surface protein P25, which along with P28 proteins protect the parasite from harmful environment inside mosquito midgut. Vaccines against these proteins induce antibodies in vertebrate host capable to inhibit parasite development in mosquito midgut and thus preventing the transmission of parasite from mosquito to other human host. Transmission-blocking vaccines help reduce malaria burden. The purpose of this study was in silico structural characterization of P25 family proteins and to predict their phylogenetic relationships with other proteins. Results indicate that members of P25 family have four EGF domains arranged in triangular fashion with major variations lying in the loop regions. All 22 cysteines are conserved forming 11 disulphide bonds. The C-loop of EGF domain IV in P25 proteins is smaller in comparison to P28 proteins. B loop of EGF domain II showed maximum RMSD variations followed by loops of EGF domain III. P25 proteins are tile-like triangular flat proteins that protect the parasite inside mosquito midgut. Obtained structures will help in understanding the biology of the parasite inside the mosquito midgut. These structures may also help in designing transmission-blocking vaccine against malaria in absence of experimentally determined structures.
Endoscopic Management of Nonlifting Colon Polyps
Authors: Friedland Shai , Shelton Andrew , Kothari Shivangi , Kochar Rajan , Chen Ann , Banerjee Subhas
Published: May 2013

Background and Study Aims. The nonlifting polyp sign of invasive colon cancer is considered highly sensitive and specific for cancer extending beyond the mid-submucosa. However, prior interventions can cause adenomas to become nonlifting due to fibrosis. It is unclear whether nonlifting adenomas can be successfully treated endoscopically. The aim of this study was to evaluate outcomes in a referral practice incorporating a standardized protocol of attempted endoscopic resection of nonlifting lesions previously treated by biopsy, polypectomy, surgery, or tattoo placement. Patients and Methods. Retrospective review of patients undergoing colonoscopy by one endoscopist at two hospitals found to have nonlifting lesions from prior interventions. Lesions with biopsy proven invasive cancer or definite endoscopic features of invasive cancer were excluded. Lesions ≥ 8 mm were routinely injected with saline prior to attempted endoscopic resection. Polypectomy was performed using a stiff snare, followed by argon plasma coagulation (APC) if necessary. Results. 26 patients each had a single nonlifting lesion with a history of prior intervention. Endoscopic resection was completed in 25 (96%). 22 required snare resection and APC. 1 patient had invasive cancer and was referred for surgery. The recurrence rate on follow-up colonoscopy was 26%. All of the recurrences were successfully treated endoscopically. There was 1 postprocedure bleed (4%), no perforations, and no other complications. Conclusions. The majority of adenomas that are nonlifting after prior interventions can be treated successfully and safely by a combination of piecemeal polypectomy and ablation. Although recurrence rates are high at 26%, these too can be successfully treated endoscopically.
Asymptomatic and Persistent Elevation of Pancreatic Enzymes in an Ulcerative Colitis Patient
Authors: Liverani Elisa , Leonardi Filippo , Castellani Lucia , Cardamone Carla , Belluzzi Andrea
Published: May 2013

Azathioprine has been extensively used in the management of inflammatory bowel diseases. It might cause pancreatic damage in the form of either asymptomatic elevation in serum amylase/lipase or overt acute pancreatitis. Here we report the case of a 61-year-old patient with ulcerative colitis who had been treated with azathioprine for three years, achieving clinical remission. During treatment he presented an asymptomatic elevation of serum pancreatic enzymes, without any signs of pancreatitis at imaging. This evidence brought us to reassess the drug dosage, without achieving a normalization of biochemical analysis. Autoimmune pancreatitis was excluded. One year after the suspension of azathioprine, we still face persistent high levels of amylase/lipase. Normalization of enzymatic values in patients who develop intolerance to azathioprine, in the form of either asymptomatic elevation in serum amylase/lipase or overt acute pancreatitis, is usually achieved in about two months after stopping drug intake. Asymptomatic elevation in serum pancreatic enzymes in the absence of pancreatic disease is reported in the literature and defined as “Gullo’s syndrome,” but nobody of the subjects studied had been treated in the past with pancreatotoxic drugs. Might this case be defined as “benign pancreatic hyperenzymemia”?
Degradation of Pesticide Chlorothalonil by Visible Light-Responsive Photocatalyst Ferrioxalate and under Solar Irradiation
Authors: Chaudhuri Malay , Zuhali Hafizi , Affam Augustine Chioma
Published: May 2013

Ferrioxalate is a visible light-responsive photocatalyst. The solar ferrioxalate/ process has high degradation efficiency because ferrioxalate is able to absorb light strongly at longer wavelength and generates hydroxyl radical with high quantum yield. Degradation of pesticide chlorothalonil in aqueous solution by ferrioxalate/ under solar irradiation was examined. The optimum operating conditions for treatment of a 300 mg/L chlorothalonil aqueous solution were obtained by using the central composite design of the response surface methodology. Under the optimum operating conditions (/COD molar ratio 2.75, /Fe3+molar ratio 75, /C2H2O4molar ratio 37.5, reaction time 90 min, and pH 3), COD, NH3-N, and TOC removal of 75.71, 47.11, and 54.33%, respectively, was achieved and the biodegradability (BOD5/COD ratio) improved from zero to 0.42. Model prediction and actual removal were in close agreement (<4% error). The solar ferrioxalate/H2O2process is effective in pretreatment of the chlorothalonil aqueous solution for biological treatment.
Precancerous Lesions in Colorectal Cancer
Authors: Sandouk Fayez , Al Jerf Feras , Al-Halabi M. H. D. Bassel
Published: May 2013

Colorectal cancer (CRC) is the third most common cause of cancer death in the world. The incidence rate (ASR) and age distribution of this disease differ between most of African-Middle-Eastern (AMAGE) and North America and Europe for many reasons. However, in all areas, “CRC” is considered as one of the most preventable cancers, because it might develop from variant processes like polyps and IBD in addition to the genetic pathogenesis which became very well known in this disease. We tried in this paper to review all the possible reasons of the differences in incidence and age between the west and AMAGE. Also we reviewed all the mutations that lead to the hereditary and familiar clustering of this disease with the correlations with the surrounding food and environment of different areas. Then, we focused on the precancerous pathology of this disease with special focusing on early detection depending on new endoscopy technology and most important genetic studies. We lastly reviewed the evidence of some of the surveillance and put suggestions about future surveillance programs and how important those programs are on the psychological aspect of the patients and their families.
Ecological Observations of NativeGeocoris pallensandG. punctipesPopulations in the Great Basin Desert of Southwestern Utah
Authors: Schuman Meredith C. , Kessler Danny , Baldwin Ian T.
Published: May 2013

Big-eyed bugs (Geocorisspp. Fallén, Hemiptera: Lygaeidae) are ubiquitous, omnivorous insect predators whose plant feeding behavior raises the question of whether they benefit or harm plants. However, several studies have investigated both the potential ofGeocorisspp. to serve as biological control agents in agriculture and their importance as agents of plant indirect defense in nature. These studies have demonstrated thatGeocorisspp. effectively reduce herbivore populations and increase plant yield. Previous work has also indicated thatGeocorisspp. respond to visual and olfactory cues when foraging and choosing their prey and that associative learning of prey and plant cues informs their foraging strategies. For these reasons,Geocorisspp. have become models for the study of tritrophic plant-herbivore-predator interactions. Here, we present detailed images and ecological observations ofG. pallensStål andG. punctipes(Say) native to the Great Basin Desert of southwestern Utah, including observations of their life histories and color morphs, dynamics of their predatory feeding behavior and prey choice over space and time, and novel aspects ofGeocorisspp.’s relationships to their host plants. These observations open up new areas to be explored regarding the behavior ofGeocorisspp. and their interactions with plant and herbivore populations.
Microwave Assisted Synthesis of ZnO Nanoparticles: Effect of Precursor Reagents, Temperature, Irradiation Time, and Additives on Nano-ZnO Morphology Development
Authors: Barreto Gastón P. , Morales Graciela , Quintanilla Ma. Luisa López
Published: May 2013

The effect of different variables (precursor reagents, temperature, irradiation time, microwave radiation power, and additives addition) on the final morphology of nano-ZnO obtained through the microwave assisted technique has been investigated. The characterization of the samples has been carried out by field emission scanning electron microscopy (FE-SEM) in transmission mode, infrared (FTIR), UV-Vis spectroscopy, and powder X-ray diffraction (XRD). The results showed that all the above-mentioned variables influenced to some extent the shape and/or size of the synthetized nanoparticles. In particular, the addition of an anionic surfactant (sodium di-2-ethylhexyl-sulfosuccinate (AOT)) to the reaction mixture allowed the synthesis of smaller hexagonal prismatic particles (100 nm), which show a significant increase in UV absorption.
Numerical Simulation of Failure Behavior of Granular Debris Flows Based on Flume Model Tests
Authors: Zhou Jian , Li Ye-xun , Jia Min-cai , Li Cui-na
Published: May 2013

In this study, the failure behaviors of debris flows were studied by flume model tests with artificial rainfall and numerical simulations (PFC3D). Model tests revealed that grain sizes distribution had profound effects on failure mode, and the failure in slope of medium sand started with cracks at crest and took the form of retrogressive toe sliding failure. With the increase of fine particles in soil, the failure mode of the slopes changed to fluidized flow. The discrete element method PFC3D can overcome the hypothesis of the traditional continuous medium mechanic and consider the simple characteristics of particle. Thus, a numerical simulations model considering liquid‐solid coupled method has been developed to simulate the debris flow. Comparing the experimental results, the numerical simulation result indicated that the failure mode of the failure of medium sand slope was retrogressive toe sliding, and the failure of fine sand slope was fluidized sliding. The simulation result is consistent with the model test and theoretical analysis, and grain sizes distribution caused different failure behavior of granular debris flows. This research should be a guide to explore the theory of debris flow and to improve the prevention and reduction of debris flow.
Segmentation of Brain MRI Using SOM-FCM-Based Method and 3D Statistical Descriptors
Authors: Ortiz Andrés , Palacio Antonio A. , Górriz Juan M. , Ramírez Javier , Salas-González Diego
Published: May 2013

Current medical imaging systems provide excellent spatial resolution, high tissue contrast, and up to 65535 intensity levels. Thus, image processing techniques which aim to exploit the information contained in the images are necessary for using these images in computer-aided diagnosis (CAD) systems. Image segmentation may be defined as the process of parcelling the image to delimit different neuroanatomical tissues present on the brain. In this paper we propose a segmentation technique using 3D statistical features extracted from the volume image. In addition, the presented method is based on unsupervised vector quantization and fuzzy clustering techniques and does not use any a priori information. The resulting fuzzy segmentation method addresses the problem of partial volume effect (PVE) and has been assessed using real brain images from the Internet Brain Image Repository (IBSR).
Modeling of the Cutting Forces in Turning Process Using Various Methods of Cooling and Lubricating: An Artificial Intelligence Approach
Authors: Cica Djordje , Sredanovic Branislav , Lakic-Globocki Gordana , Kramar Davorin
Published: May 2013

Cutting forces are one of the inherent phenomena and a very significant indicator of the metal cutting process. The work presented in this paper is an investigation of the prediction of these parameters in turning using soft computing techniques. During the experimental research focus is placed on the application of various methods of cooling and lubricating of the cutting zone. On this occasion were used the conventional method of cooling and lubricating, high pressure jet assisted machining, and minimal quantity lubrication technique. The data obtained by experiment are used to create two different models, namely, artificial neural network and adaptive networks based fuzzy inference systems for prediction of cutting forces. Furthermore, both models are compared with the experimental data and results are indicated.