bluuebunny/crossref_metadata_2025 huggingface dataset:
Endothelial function and vascular oxidative stress in long-lived GH/IGF-deficient Ames dwarf mice
Authors: Csiszar Anna , Labinskyy Nazar , Perez Viviana , Recchia Fabio A. , Podlutsky Andrej , Mukhopadhyay Partha , Losonczy Gyorgy , Pacher Pal , Austad Steven N. , Bartke Andrzej , Ungvari Zoltan
Published: August 2008

Hypopituitary Ames dwarf mice have low circulating growth hormone (GH)/IGF-I levels, and they have extended longevity and exhibit many symptoms of delayed aging. To elucidate the vascular consequences of Ames dwarfism we compared endothelial O2•−and H2O2production, mitochondrial reactive oxygen species (ROS) generation, expression of antioxidant enzymes, and nitric oxide (NO) production in aortas of Ames dwarf and wild-type control mice. In Ames dwarf aortas endothelial O2•−and H2O2production and ROS generation by mitochondria were enhanced compared with those in vessels of wild-type mice. In Ames dwarf aortas there was a less abundant expression of Mn-SOD, Cu,Zn-SOD, glutathione peroxidase (GPx)-1, and endothelial nitric oxide synthase (eNOS). NO production and acetylcholine-induced relaxation were also decreased in aortas of Ames dwarf mice. In cultured wild-type mouse aortas and in human coronary arterial endothelial cells treatment with GH and IGF significantly reduced cellular O2•−and H2O2production and ROS generation by mitochondria and upregulated expression of Mn-SOD, Cu,Zn-SOD, GPx-1, and eNOS. Thus GH and IGF-I promote antioxidant phenotypic changes in the endothelial cells, whereas Ames dwarfism leads to vascular oxidative stress.
Modeling of the adrenergic response of the human IKs current (hKCNQ1/hKCNE1) stably expressed in HEK-293 cells
Authors: Imredy John P. , Penniman Jacob R. , Dech Spencer J. , Irving Winston D. , Salata Joseph J.
Published: August 2008

Stable coexpression of human (h)KCNQ1 and hKCNE1 in human embryonic kidney (HEK)-293 cells reconstitutes a nativelike slowly activating delayed rectifier K+ current (HEK- IKs), allowing β-adrenergic modulation of the current by stimulation of endogenous receptors in the host cell line. HEK- IKs was enhanced two- to fourfold by isoproterenol (EC50 = 13 nM), forskolin (10 μM), or 8-(4-chlorophenylthio)adenosine 3′,5′-cyclic monophosphate (50 μM), indicating an intact cAMP-dependent ion channel-regulating pathway analogous to the PKA-dependent regulation observed in native cardiac myocytes. Activation kinetics of HEK- IKs were accurately fit with a novel modified second-order Hodgkin-Huxley (H-H) gating model incorporating a fast and a slow gate, each independent of each other in scale and adrenergic response, or a “heterodimer” model. Macroscopically, β-adrenergic enhancement shifted the current activation threshold to more negative potentials and accelerated activation kinetics while leaving deactivation kinetics relatively unaffected. Modeling of the current response using the H-H model indicated that observed changes in gating could be explained by modulation of the opening rate of the fast gate. Under control conditions at nearly physiological temperatures (35°C), rate-dependent accumulation of HEK- IKs was observed only at pulse frequencies exceeding 3 Hz. Rate-dependent accumulation of IKs at high pulsing rate had two phases, an initial staircaselike effect followed by a slower, incremental accumulation phase. These phases are readily interpreted in the context of a heterodimeric H-H model with two independent gates with differing closing rates. In the presence of isoproterenol after normalizing for its tonic effects, rate-dependent accumulation of HEK- IKs appeared at lower pulse frequencies and was slightly enhanced (∼25%) over control.
Adenosine A2Areceptor activation reduces infarct size in the isolated, perfused mouse heart by inhibiting resident cardiac mast cell degranulation
Authors: Rork Tyler H. , Wallace Kori L. , Kennedy Dylan P. , Marshall Melissa A. , Lankford Amy R. , Linden Joel
Published: August 2008

Mast cells are found in the heart and contribute to reperfusion injury following myocardial ischemia. Since the activation of A2Aadenosine receptors (A2AARs) inhibits reperfusion injury, we hypothesized that ATL146e (a selective A2AAR agonist) might protect hearts in part by reducing cardiac mast cell degranulation. Hearts were isolated from five groups of congenic mice: A2AAR+/+mice, A2AAR−/−mice, mast cell-deficient (KitW-sh/W-sh) mice, and chimeric mice prepared by transplanting bone marrow from A2AAR−/−or A2AAR+/+mice to radiation-ablated A2AAR+/+mice. Six weeks after bone marrow transplantation, cardiac mast cells were repopulated with >90% donor cells. In isolated, perfused hearts subjected to ischemia-reperfusion injury, ATL146e or CGS-21680 (100 nmol/l) decreased infarct size (IS; percent area at risk) from 38 ± 2% to 24 ± 2% and 22 ± 2% in ATL146e- and CGS-21680-treated hearts, respectively ( P < 0.05) and significantly reduced mast cell degranulation, measured as tryptase release into reperfusion buffer. These changes were absent in A2AAR−/−hearts and in hearts from chimeric mice with A2AAR−/−bone marrow. Vehicle-treated KitW-sh/W-shmice had lower IS (11 ± 3%) than WT mice, and ATL146e had no significant protective effect (16 ± 3%). These data suggest that in ex vivo, buffer-perfused hearts, mast cell degranulation contributes to ischemia-reperfusion injury. In addition, our data suggest that A2AAR activation is cardioprotective in the isolated heart, at least in part by attenuating resident mast cell degranulation.
Insufficient flow reduction during LBNP in both splanchnic and lower limb areas is associated with orthostatic intolerance after bedrest
Authors: Arbeille P. , Kerbeci P. , Mattar L. , Shoemaker J. K. , Hughson R.
Published: August 2008

We quantified the impact of a 60-day head-down tilt bed rest (HDBR) with countermeasures on the arterial response to supine lower body negative pressure (LBNP). Twenty-four women [8 control (Con), 8 exercise + LBNP (Ex-LBNP), and 8 nutrition (Nut) subjects] were studied during LBNP (0 to −45 mmHg) before (pre) and on HDBR day 55 (HDBR-55). Left ventricle diastolic volume (LVDV) and mass, flow velocities in the middle cerebral artery (MCA flow) and femoral artery (femoral flow), portal vein cross-sectional area (portal flow), and lower limb resistance (femoral resistance index) were measured. Muscle sympathetic nerve activity (MSNA) was measured in the fibular nerve. Subjects were identified as finishers or nonfinishers of the 10-min post-HDBR tilt test. At HDBR-55, LVDV, mass, and portal flow were decreased from pre-HDBR ( P < 0.05) in the Con and Nut groups only. During LBNP at HDBR-55, femoral and portal flow decreased less, whereas leg MSNA increased similarly, compared with pre-HDBR in the Con, Nut, and NF groups; 11 of 13 nonfinishers showed smaller LBNP-induced reductions in both femoral and portal flow (less vasoconstriction), whereas 10 of 11 finishers maintained vasoconstriction in either one or both regions. The relative distribution of blood flow in the cerebral versus portal and femoral beds during LBNP [MCA flow/(femoral + portal flow)] increased or reduced <15% from pre-HDBR in 10 of 11 finishers but decreased >15% from pre-HDBR in 11 of 13 nonfinishers. Abnormal vasoconstriction in both the portal and femoral vascular areas was associated with orthostatic intolerance. The vascular deconditioning was partially prevented by Ex-LBNP.
Soluble guanylyl cyclase activation by HMR-1766 (ataciguat) in cells exposed to oxidative stress
Authors: Zhou Zongmin , Pyriochou Anastasia , Kotanidou Anastasia , Dalkas Georgios , van Eickels Martin , Spyroulias Georgios , Roussos Charis , Papapetropoulos Andreas
Published: August 2008

Many vascular diseases are characterized by increased levels of ROS that destroy the biological activity of nitric oxide and limit cGMP formation. In the present study, we investigated the cGMP-forming ability of HMR-1766 in cells exposed to oxidative stress. Pretreatment of smooth muscle cells with H2O2reduced cGMP production stimulated by sodium nitroprusside (SNP) or BAY 41-2272. However, pretreatment with H2O2significantly increased HMR-1766 responses. Similar results were obtained with SIN-1, menadione, and rotenone. In addition, HMR-1766 was more effective in stimulating heme-free sGC compared with the wild-type enzyme. Interestingly, in cells expressing heme-free sGC, H2O2inhibited instead of potentiated HMR-1766 responses, suggesting that the ROS-induced enhancement of cGMP formation was heme dependent. Moreover, using truncated forms of sGC, we observed that the NH2-terminus of the β1-subunit is required for the action of HMR-1766. Finally, to study tolerance development to HMR-1766, cells were pretreated with this sGC activator and reexposed to HMR-1766 or SNP. Results from these experiments demonstrated lack of tolerance development to HMR-1766 as well as lack of cross-tolerance with SNP. We conclude that HMR-1766 is an improved sGC activator as it has the ability to activate oxidized/heme-free sGC and is resistant to the development of tolerance; these observations make HMR-1766 a promising agent for treating diseases associated with increased vascular tone combined with enhanced ROS production.
Cardiac glycogen accumulation after dexamethasone is regulated by AMPK
Authors: Puthanveetil Prasanth , Wang Fang , Kewalramani Girish , Kim Min Suk , Hosseini-Beheshti Elham , Ng Natalie , Lau William , Pulinilkunnil Thomas , Allard Michael , Abrahani Ashraf , Rodrigues Brian
Published: August 2008

Glycogen is an immediate source of glucose for cardiac tissue to maintain its metabolic homeostasis. However, its excess brings about cardiac structural and physiological impairments. Previously, we have demonstrated that in hearts from dexamethasone (Dex)-treated animals, glycogen accumulation was enhanced. We examined the influence of 5′-AMP-activated protein kinase (AMPK) on glucose entry and glycogen synthase as a means of regulating the accumulation of this stored polysaccharide. After Dex, cardiac tissue had a limited contribution toward the development of whole body insulin resistance. Measurement of glucose transporter 4 (GLUT4) at the plasma membrane revealed an excess presence of this transporter protein at this location. Interestingly, this was accompanied by an increase in GLUT4 in the intracellular membrane fraction, an effect that was well correlated with increased GLUT4 mRNA. Both total and phosphorylated AMPK increased after Dex. Immunoprecipitation of Akt substrate of 160 kDa (AS160) followed by Western blot analysis demonstrated no change in Akt phosphorylation at Ser473and Thr308in Dex-treated hearts. However, there was a significant increase in AMPK phosphorylation at Thr172, which correlated well with AS160 phosphorylation. In Dex-treated hearts, there was a considerable reduction in the phosphorylation of glycogen synthase, whereas glycogen synthase kinase-3-β phosphorylation was augmented. Our data suggest that AMPK-mediated glucose entry combined with the activation of glycogen synthase and a reduction in glucose oxidation (Qi et al., Diabetes 53: 1790–1797, 2004) act together to promote glycogen storage. Should these effects persist chronically in the heart, they may explain the increased morbidity and mortality observed with long-term excesses in endogenous or exogenous glucocorticoids.
Contrasting effects of presynaptic α2-adrenergic autoinhibition and pharmacologic augmentation of presynaptic inhibition on sympathetic heart rate control
Authors: Miyamoto Tadayoshi , Kawada Toru , Yanagiya Yusuke , Akiyama Tsuyoshi , Kamiya Atsunori , Mizuno Masaki , Takaki Hiroshi , Sunagawa Kenji , Sugimachi Masaru
Published: August 2008

Presynaptic α2-adrenergic receptors are known to exert feedback inhibition on norepinephrine release from the sympathetic nerve terminals. To elucidate the dynamic characteristics of the inhibition, we stimulated the right cardiac sympathetic nerve according to a binary white noise signal while measuring heart rate (HR) in anesthetized rabbits ( n = 6). We estimated the transfer function from cardiac sympathetic nerve stimulation to HR and the corresponding step response of HR, with and without the blockade of presynaptic inhibition by yohimbine (1 mg/kg followed by 0.1 mg·kg−1·h−1iv). We also examined the effect of the α2-adrenergic receptor agonist clonidine (0.3 and 1.5 mg·kg−1·h−1iv) in different rabbits ( n = 5). Yohimbine increased the maximum step response (from 7.2 ± 0.8 to 12.2 ± 1.7 beats/min, means ± SE, P < 0.05) without significantly affecting the initial slope (0.93 ± 0.23 vs. 0.94 ± 0.22 beats·min−1·s−1). Higher dose but not lower dose clonidine significantly decreased the maximum step response (from 6.3 ± 0.8 to 6.8 ± 1.0 and 2.8 ± 0.5 beats/min, P < 0.05) and also reduced the initial slope (from 0.56 ± 0.07 to 0.51 ± 0.04 and 0.22 ± 0.06 beats·min−1·s−1, P < 0.05). Our findings indicate that presynaptic α2-adrenergic autoinhibition limits the maximum response without significantly compromising the rapidity of effector response. In contrast, pharmacologic augmentation of the presynaptic inhibition not only attenuates the maximum response but also results in a sluggish effector response.
Decreased connexin43 expression in the mouse heart potentiates pacing-induced remodeling of repolarizing currents
Authors: Kontogeorgis Andrianos , Li Xiaodong , Kang Eunice Y. , Feig Jonathan E. , Ponzio Marc , Kang Guoxin , Kaba Riyaz A. , Wit Andrew L. , Fisher Edward A. , Morley Gregory E. , Peters Nicholas S. , Coetzee William A. , Gutstein David E.
Published: August 2008

Gap junction redistribution and reduced expression, a phenomenon termed gap junction remodeling (GJR), is often seen in diseased hearts and may predispose toward arrhythmias. We have recently shown that short-term pacing in the mouse is associated with changes in connexin43 (Cx43) expression and localization but not with increased inducibility into sustained arrhythmias. We hypothesized that short-term pacing, if imposed on murine hearts with decreased Cx43 abundance, could serve as a model for evaluating the electrophysiological effects of GJR. We paced wild-type (normal Cx43 abundance) and heterozygous Cx43 knockout (Cx43+/−; 66% mean reduction in Cx43) mice for 6 h at 10–15% above their average sinus rate. We investigated the electrophysiological effects of pacing on the whole animal using programmed electrical stimulation and in isolated ventricular myocytes with patch-clamp studies. Cx43+/− myocytes had significantly shorter action potential durations (APD) and increased steady-state ( Iss) and inward rectifier ( IK1) potassium currents compared with those of wild-type littermate cells. In Cx43+/− hearts, pacing resulted in a significant prolongation of ventricular effective refractory period and APD and significant diminution of Iss compared with unpaced Cx43+/− hearts. However, these changes were not seen in paced wild-type mice. These data suggest that Cx43 abundance plays a critical role in regulating currents involved in myocardial repolarization and their response to pacing. Our study may aid in understanding how dyssynchronous activation of diseased, Cx43-deficient myocardial tissue can lead to electrophysiological changes, which may contribute to the worsened prognosis often associated with pacing in the failing heart.
Cold pressor test in the rat: medullary and spinal pathways and neurotransmitters
Authors: Nakamura Takeshi , Kawabe Kazumi , Sapru Hreday N.
Published: August 2008

This study was designed to delineate the medullary and spinal pathways mediating the cardiovascular responses to cold pressor test (CPT) and to identify neurotransmitters in these pathways. Experiments were done in barodenervated, urethane-anesthetized, male Wistar rats. The CPT was performed by immersing the limbs and ventral half of the body of the rat in ice-cold water (0.5°C) for 2 min. CPT elicited an immediate increase in mean arterial pressure (MAP), heart rate (HR), and greater splanchnic nerve activity (GSNA). Bilateral blockade of ionotropic glutamate receptors (iGLURs) in the rostral ventrolateral medullary pressor area (RVLM) significantly attenuated the CPT-induced responses. Bilateral blockade of γ-aminobutyric acid (GABA) receptors, but not iGLURs, in the nucleus ambiguus (nAmb) significantly reduced the CPT-induced increases in HR, but not MAP. Blockade of spinal iGLURs caused a significant reduction in CPT-induced increases in MAP and GSNA, whereas the increases in HR were reduced to a lesser extent. Combination of the blockade of spinal iGLURs and bilateral vagotomy or intravenous atropine almost completely blocked CPT-induced tachycardia. Midcollicular decerebration significantly reduced CPT-induced increases in MAP and HR. These results indicated that: 1) CPT-induced increases in MAP, HR, and GSNA were mediated by activation of iGLURs in the RVLM and spinal cord, 2) activation of GABA receptors in the nAmb also contributed to the CPT-induced tachycardic responses, and 3) brain areas rostral to the brain stem also participated in the CPT-induced pressor and tachycardic responses.
Role of oxidative stress in multiparity-induced endothelial dysfunction
Authors: Tawfik Huda E. , Cena Jonathan , Schulz Richard , Kaufman Susan
Published: August 2008

Multiparity is associated with increased risk of cardiovascular disease. We tested whether multiparity induces oxidative stress in rat vascular tissue. Coronary arteries and thoracic aorta were isolated from multiparous and age-matched virgin rats. Relaxation to ACh and sodium nitroprusside (SNP) was measured by wire myography. We also tested the effect of the superoxide dismutase mimetic MnTE2PyP (30 μM), the NADPH oxidase inhibitor apocynin (10 μM), and the peroxynitrite scavenger FeTPPs (10 μM) on ACh-mediated relaxation in coronary arteries. Vascular superoxide anion was measured using the luminol derivative L-012 and nitric oxide (NO) generation by the Griess reaction. Multiparity reduced maximal response and sensitivity to ACh in coronary arteries [maximal relaxation (Emax): multiparous 49 ± 3% vs. virgins 95% ± 3%; EC50: multiparous 135 ± 1 nM vs. virgins 60 ± 1 nM], and in aortic rings (Emax: multiparous 38 ± 3% vs. virgins 79 ± 4%; EC50: multiparous 160 ± 2 nM vs. virgins 90 ± 3 nM). Coronary arteries from the two groups relaxed similarly to SNP. Superoxide anions formation was significantly higher in both coronary arteries (2.8-fold increase) and aorta (4.1-fold increase) from multiparous rats compared with virgins. In multiparous rats, incubation with MnTE2PyP, apocynin, and FeTPPs improved maximal relaxation to ACh (MnTE2PyP: 74 ± 5%; vehicle: 41 ± 5%; apocynin: 73 ± 3% vs. vehicle: 41 ± 3%; FeTPPs: 72 ± 3% vs. vehicle: 46 ± 3%) and increased sensitivity (EC50: MnTE2PyP: 61 ± 0.5 nM vs. vehicle: 91 ± 1 nM; apocynin: 45 ± 3 nM vs. vehicle: 91 ± 6 nM; FeTPP: 131 ± 2 nM vs. vehicle: 185 ± 1 nM). Multiparity also reduced total nitrate/nitrite levels (multiparous: 2.5 ± 2 μmol/mg protein vs. virgins: 7 ± 1 μmol/mg protein) and endothelial nitric oxide synthase protein levels (multiparous: 0.53 ± 0.1 protein/actin vs. virgins: 1.0 ± 0.14 protein/actin). These data suggest that multiparity induces endothelial dysfunction through decreased NO bioavailability and increased reactive oxygen species formation.
Reactive oxygen species from NADPH oxidase contribute to altered pulmonary vascular responses in piglets with chronic hypoxia-induced pulmonary hypertension
Authors: Fike Candice D. , Slaughter James C. , Kaplowitz Mark R. , Zhang Yongmei , Aschner Judy L.
Published: August 2008

Our main objective was to determine whether reactive oxygen species (ROS), such as superoxide (O2−) and hydrogen peroxide (H2O2), contribute to altered pulmonary vascular responses in piglets with chronic hypoxia-induced pulmonary hypertension. Piglets were raised in either room air (control) or hypoxia for 3 days. The effect of the cell-permeable superoxide dismutase mimetic (SOD; M40403) and/or PEG-catalase (PEG-CAT) on responses to acetylcholine (ACh) was measured in endothelium-intact and denuded pulmonary resistance arteries (PRAs; 90-to-300-μm diameter). To determine whether NADPH oxidase is an enzymatic source of ROS, PRA responses to ACh were measured in the presence and absence of a NADPH oxidase inhibitor, apocynin (APO). A Western blot technique was used to assess expression of the NADPH oxidase subunit, p67phox. A lucigenin-derived chemiluminescence technique was used to measure ROS production stimulated by the NADPH oxidase substrate, NADPH. ACh responses, which were dilation in intact control arteries but constriction in both intact and denuded hypoxic arteries, were diminished by M40403, PEG-CAT, the combination of M40403 plus PEG-CAT, as well as by APO. Although total amounts were not different, membrane-associated p67phox was greater in PRAs from hypoxic compared with control piglets. NADPH-stimulated lucigenin luminescence was nearly doubled in PRAs from hypoxic vs. control piglets. We conclude that ROS generated by NADPH oxidase contribute to the aberrant pulmonary arterial responses in piglets exposed to 3 days of hypoxia.
Progressive dysfunction of nitric oxide synthase in a lamb model of chronically increased pulmonary blood flow: a role for oxidative stress
Authors: Oishi Peter E. , Wiseman Dean A. , Sharma Shruti , Kumar Sanjiv , Hou Yali , Datar Sanjeev A. , Azakie Anthony , Johengen Michael J. , Harmon Cynthia , Fratz Sohrab , Fineman Jeffrey R. , Black Stephen M.
Published: August 2008

Cardiac defects associated with increased pulmonary blood flow result in pulmonary vascular dysfunction that may relate to a decrease in bioavailable nitric oxide (NO). An 8-mm graft (shunt) was placed between the aorta and pulmonary artery in 30 late gestation fetal lambs; 27 fetal lambs underwent a sham procedure. Hemodynamic responses to ACh (1 μg/kg) and inhaled NO (40 ppm) were assessed at 2, 4, and 8 wk of age. Lung tissue nitric oxide synthase (NOS) activity, endothelial NOS (eNOS), neuronal NOS (nNOS), inducible NOS (iNOS), and heat shock protein 90 (HSP90), lung tissue and plasma nitrate and nitrite (NOx), and lung tissue superoxide anion and nitrated eNOS levels were determined. In shunted lambs, ACh decreased pulmonary artery pressure at 2 wk ( P < 0.05) but not at 4 and 8 wk. Inhaled NO decreased pulmonary artery pressure at each age ( P < 0.05). In control lambs, ACh and inhaled NO decreased pulmonary artery pressure at each age ( P < 0.05). Total NOS activity did not change from 2 to 8 wk in control lambs but increased in shunted lambs (ANOVA, P < 0.05). Conversely, NOxlevels relative to NOS activity were lower in shunted lambs than controls at 4 and 8 wk ( P < 0.05). eNOS protein levels were greater in shunted lambs than controls at 4 wk of age ( P < 0.05). Superoxide levels increased from 2 to 8 wk in control and shunted lambs (ANOVA, P < 0.05) and were greater in shunted lambs than controls at all ages ( P < 0.05). Nitrated eNOS levels were greater in shunted lambs than controls at each age ( P < 0.05). We conclude that increased pulmonary blood flow results in progressive impairment of basal and agonist-induced NOS function, in part secondary to oxidative stress that decreases bioavailable NO.
Preservation of cGMP-induced relaxation of pulmonary veins of fetal lambs exposed to chronic high altitude hypoxia: role of PKG and Rho kinase
Authors: Gao Yuansheng , Portugal Ada D. , Liu Jie , Negash Sewite , Zhou Weilin , Tian Jia , Xiang Ruolan , Longo Lawrence D. , Raj J. Usha
Published: August 2008

The roles of Rho kinase (ROCK) and cGMP-dependent protein kinase (PKG) in cGMP-mediated relaxation of fetal pulmonary veins exposed to chronic hypoxia (CH) were investigated. Fourth generation pulmonary veins were dissected from near-term fetuses (∼140 days of gestation) delivered from ewes exposed to chronic high altitude hypoxia for ∼110 days (CH) and from control ewes. After constriction with endothelin-1, 8-bromoguanosine 3′,5′-cyclic monophosphate (8-Br-cGMP) caused a similar relaxation of both control and CH vessels. Rp-8-Br-PET-cGMPS (a PKG inhibitor) inhibited whereas Y-27632 (a ROCK inhibitor) augmented relaxation of control veins to 8-Br-cGMP. These effects were significantly diminished in CH veins. PKG protein expression and activity were greater whereas ROCK protein expression and activity were less in CH vessels compared with controls. Phosphorylation of threonine 696 (ROCK substrate) and serine 695 (PKG substrate) of the regulatory myosin phosphatase targeting subunit MYPT1 of myosin light chain (MLC) phosphatase was stimulated to a lesser extent in CH than in control veins by endothelin-1 (ROCK stimulant) and 8-Br-cGMP (PKG stimulant), respectively. The phosphorylation and dephosphorylation of MLC caused by endothelin-1 and 8-Br-cGMP, respectively, were less in CH veins than in controls. These results suggest that CH in utero upregulates PKG activity but attenuates PKG action in fetal pulmonary veins. These effects are offset by the diminished ROCK action on MYPT1 and MLC and thus lead to an unaltered response to cGMP.
EGF and K+channel activity control normal and cystic fibrosis bronchial epithelia repair
Authors: Trinh Nguyen Thu Ngan , Privé Anik , Maillé Emilie , Noël Josette , Brochiero Emmanuelle
Published: August 2008

Severe lesions of airway epithelia are observed in cystic fibrosis (CF) patients. The regulatory mechanisms of cell migration and proliferation processes, involved in the repair of injured epithelia, then need to be better understood. A model of mechanical wounding of non-CF (NuLi) and CF (CuFi) bronchial monolayers was employed to study the repair mechanisms. We first observed that wound repair, under paracrine and autocrine EGF control, was slower (up to 33%) in CuFi than in NuLi. Furthermore, EGF receptor (EGFR) activation, following wounding, was lower in CuFi than in NuLi monolayers. Cell proliferation and migration assays indicated a similar rate of proliferation in both cell lines but with reduced (by 25%) CuFi cell migration. In addition, cell migration experiments performed in the presence of conditioned medium, collected from NuLi and CuFi wounded bronchial monolayers, suggested a defect in EGF/EGFR signaling in CF cells. We ( 49 ) recently demonstrated coupling between the EGF response and K+channel function, which is crucial for EGF-stimulated alveolar repair. In CuFi cells, lower EGF/EGFR signaling was accompanied by a 40–70% reduction in K+currents and KvLQT1, ATP-sensitive potassium (KATP), and Ca2+-activated K+(KCa3.1) channel expression. In addition, EGF-stimulated bronchial wound healing, cell migration, and proliferation were severely decreased by K+channel inhibitors. Finally, acute CFTR inhibition failed to reduce wound healing, EGF secretion, and K+channel expression in NuLi. In summary, the delay in CuFi wound healing could be due to diminished EGFR signaling coupled with lower K+channel function, which play a crucial role in bronchial repair.
X-ray diffraction characterization of the microstructure of close-packed hexagonal nanomaterials
Authors: Pu Zhao-hui , Yang Chuan-zheng , Qin Pei , Lou Yu-wan , Cheng Li-fang
Published: August 2008

A general least-squares technique for X-ray diffraction line broadening analysis has been developed. The technique can be used to determine single, double, and triple line broadening effects caused by small particle sizes, microstrain, stacking faults, or all three presented in a closed-packed hexagonal nanomaterial. The technique was applied to characterize the microstructure of β-Ni(OH)2, a negative electrode material in nickel-metal hydride (NiMH) batteries. Double line broadening effects caused by both small crystallite sizes and stacking faults in β-Ni(OH)2were detected and analyzed. Triple line broadening effects caused simultaneously by small crystallite sizes, microstrain, and stacking faults were detected in β-Ni(OH)2after activation and charge-discharge cycle tests. The triple line broadening effects were found to be selective and most pronounced for diffraction lines withh−k=3n±1. The broadening effects were larger whenl=even, but smaller whenl=odd. The shape and the average size of the crystallites, microstrain, and stacking fault probability in β-Ni(OH)2changed dramatically after activation and charge-discharge cycles. The method was also applied to characterize and investigate the microstructure of nano ZnO materials. Results indicate that no selective broadening appears in the XRD patterns of the nano ZnO materials. The average crystallite sizes were different slightly, and the stacking fault probabilities differed significantly with different dopants.
Powder X-ray diffraction data of new bismuth yttrium gadolinium oxides
Authors: Alizadeh M. , Ahmadi K. , Maghsudipour A. , Moztarzadeh F.
Published: August 2008

X-ray powder diffraction data for five new bismuth yttrium gadolinium oxide compounds synthesized by solid state reaction method are reported. The unit cell dimensions were determined from X-ray diffraction methods, using CuKα radiation, and evaluated by indexing programs. The cubic phase was the sole crystalline phase detected by X-ray diffraction analysis in Bi0.88Y0.06Gd0.06O1.5, Bi0.88Y0.08Gd0.04O1.5, Bi0.82Y0.09Gd0.09O1.5, Bi0.82Y0.12Gd0.06O1.5, and Bi0.82Y0.06Gd0.12O1.5 samples with lattice constants of a=5.5371(1) Å, a=5.5368(1) Å, a=5.5303(2) Å, a=5.53487(8) Å, and a=5.5279(1) Å, respectively. The results are in good agreement with those reported for bismuth yttrium oxide (Bi0.75Y0.25)O1.5 (PDF 01-084-1450).
Nonlinear thermal expansion in Li2NiMn3O8
Authors: Zeng Lingmin , Chen Yeqing , He Wei , Nong Liangqin
Published: August 2008

A lattice thermal expansion study on Li2NiMn3O8, a high-voltage cathode material for lithium-ion batteries, was carried out by high-temperature X-ray diffraction from room temperature to 973 K. Rietveld refinement of a high-quality room-temperature diffraction pattern confirmed that Li2NiMn3O8 has the cubic Al2MgO4 spinel type of crystal structure. The analysis of the high-temperature X-ray diffraction patterns showed that the Li2NiMn3O8 structure remained stable and no phase transition was detected over the temperature range from 298 to 973 K. As expected, the value of lattice parameter a or unit cell volume V increases with increasing temperature. The increase in a or V is linear only in the low-temperature region and nonlinear over the entire temperature range from 298 to 973 K. Least-squares analysis of the data for a or V showed the thermal expansion of a or V for Li2NiMn3O8 can best be fitted by a 3-degree polynomial function of temperature. The linear thermal expansion coefficients for a and V averaged over the entire temperature range from 298 to 973 K were also calculated, and αTa=1.10×10−5 K−1; αTV=3.29×10−5 K−1.
Brochantite-2M2from Pierre Plate Mine, Vizille
Authors: Crichton Wilson A. , Müller Harald
Published: August 2008

Evidence for the recently described 2M2polytype of brochantite from X-ray powder diffraction investigation of secondary alteration products of ore material from the Pierre Plate Mine, Vizille, Isère, France is presented. This report is the first to describe the 2M2polytype from locations outside of Italy and through the use of powder XRD methods. In the procedure used herein, developed in a study by Merlinoet al.[Eur. J. Mineral15, 267–275 (2003)], we have used family reflections, common to both main types of brochantite, as the source of approximate cell parameters from which we obtain positions of characteristic reflections to demonstrate the unique choice of polytype, before final refinement stage. This method demonstrates that the determination of polytype is possible from powder data, for samples typical of both geological and urban environments. Least-squares refined cell parameters for the 2M2polytype from Pierre Plate area=12.7409(8) Å,b=9.8371(6) Å,c=6.0109(3) Å, anda=90.135(9)°, constrained in space groupP21/n11.
Loss of homologous recombination or non-homologous end-joining leads to radial formation following DNA interstrand crosslink damage
Authors: Hanlon Newell A.E. , Hemphill A. , Akkari Y.M.N. , Hejna J. , Moses R.E. , Olson S.B.
Published: September 2008

High levels of interstrand cross-link damage in mammalian cells cause chromatid breaks and radial formations recognizable by cytogenetic examination. The mechanism of radial formation observed following DNA damage has yet to be determined. Due to recent findings linking homologous recombination and non-homologous end-joining to the action of the Fanconi anemia pathway, we speculated that radials might be the result of defects in either of the pathways of DNA repair. To test this hypothesis, we have investigated the role of homologous recombination proteins RAD51 and RAD52, non-homologous end-joining proteins Ku70 and LIG4, and protein MRE11 in radial formation and cell survival following interstrand crosslink damage with mitomycin C. For the studies we used small inhibitory RNA to deplete the proteins from cells, allowing for evaluation of radial formation and cell survival. In transformed normal human fibroblasts, depletion of these proteins increased interstrand crosslink sensitivity as manifested by decreased cell survival and increased radial formation. These results demonstrate that inactivation of proteins from either of the two separate DNA repair pathways increases cellular sensitivity to interstrand crosslinks, indicating each pathway plays a role in the normal response to interstrand crosslink damage. We can also conclude that homologous recombination or non-homologous end-joining are not required for radial formation, since radials occur with depletion of these pathways.
Differential loss of expression of common fragile site genes between oral tongue and oropharyngeal squamous cell carcinomas
Authors: Soderberg C. , Perez D.S. , Ukpo O.C. , Liang X. , O’Reilly A.G. , Moore E.J. , Kademani D. , Smith D.I.
Published: September 2008

The common fragile sites (CFSs) are large regions of profound genomic instability found in all individuals. A number of the CFSs have been found to span genes that extend over large genomic regions (>700 kb). The expression of these genes is frequently abrogated in a number of different cancers and several of them have already been shown to function as tumor suppressor genes, both in vitro and in vivo. We analyzed the expression of 14 large CFS genes in two distinct groups of head and neck cancers using real-time RT-PCR. The first were oral tongue squamous cell carcinomas (SCCs) and the second were base of tongue/tonsillar (oropharyngeal) SCCs. These two groups were previously examined for the presence of human papillomavirus (HPV) and while 46% of the oropharyngeal cancers were positive for HPV16 only one of 52 oral cancers contained HPV16 sequences. We observed a distinct pattern of loss of expression of the large CFS genes in the two groups of head and neck cancers. In addition, there was no correlation between the relative instability in different CFS regions and which genes were inactivated. Thus, this report demonstrates another distinction between these two groups of head and neck cancer. In addition, it suggests that there is selection for loss of expression of specific CFS genes in these cancers.
Localization of sense and antisense transcripts of Prdx2 gene in mouse tissues
Authors: Chiba M. , Kubo M. , Miura T. , Sato T. , Rezaeian A.H. , Kiyosawa H. , Ohkohchi N. , Yasue H.
Published: September 2008

Recently, it has been reported that antisense RNAs are transcribed from a large number of genes in various species including human and mouse. The Prdx2 gene, which is indicated to be involved in signal transduction related to platelet-derived growth factor as well as to protection from oxidizing agents, has been shown to produce sense and antisense transcripts. To obtain clues for possible roles of Prdx2 antisense transcripts, we have performed Northern blot analysis and in situ hybridization on tissues of 8-week-old C57BL/6J mice. The Northern blot analysis revealed that major parts of sense and antisense transcripts were poly(A–)-RNA. The analysis of the fractionated RNA of fibroblasts indicated that the poly(A–)-RNA would be localized in the cytoplasm of cells. The in situ hybridization demonstrated that the sense and antisense transcripts were localized in almost the same limited areas of brain, testis, and spleen. It also revealed that the sense and antisense transcripts coexisted in Purkinje cells. In thymus and stomach, the antisense transcripts were detected, but sense transcripts were not. When tissues of BALB/c mice were examined by in situ hybridization, the observations were essentially the same as those of C57BL/6J except that it appeared that the amounts of sense and antisense transcripts in testis of BALB/c were greater than those in C57BL/6J, and that the amounts of antisense transcripts in stomach of BALB/c were much smaller than those in C57BL/6J.
PHF5A represents a bridge protein between splicing proteins and ATP-dependent helicases and is differentially expressed during mouse spermatogenesis
Authors: Rzymski T. , Grzmil P. , Meinhardt A. , Wolf S. , Burfeind P.
Published: September 2008

PHF5A is a highly conserved protein from yeast to man, and based on studies in yeast, it was suggested that the homologous protein RDS3P in S. cerevisiae takes part in the organization of U2 snRNP particles. By using the yeast two-hybrid assay we could demonstrate that PHF5A interacted both with ATP-dependent helicases EP400 and DDX1 and with arginine-serine (RS)-rich domains of splicing factors U2AF1 and SFRS5 in mouse. Furthermore, domain interaction studies revealed that PHF5A interaction with EP400 and DDX1 is restricted to the N-terminal part of PHF5A, whereas the C-terminal region of PHF5A was found to be responsible for the association with U2AF1 and SFRS5. By using the yeast three-hybrid assay, we could further show that both EP400 and DDX1 interacted only indirectly with U2AF1 and SFRS5 proteins via the bridge protein PHF5A. The subcellular localization of a PHF5A-GFP fusion protein was predominantly observed in the nucleus and, in addition, PHF5A co-localized with both U2AF1 and SFRS5 proteins in nuclear speckles of NIH3T3 cells. Moreover, expression analyses demonstrated that PHF5A and U2AF1 gene expression coincided in spermatocytes during murine spermatogenesis and interaction between these proteins was also detectable in the spermatocyte-specific cell line GC-4spc by using in vivo co-immunoprecipitation studies. Taken together, our results indicate that PHF5A resembles a protein which interacts with splicing factors U2AF1 and SFRS5 and helicases EP400 and DDX1 and functions as a bridge protein between these proteins.
Identification of a new reciprocal translocation in an AI bull by synaptonemal complex analysis, followed by chromosome painting
Authors: Switonski M. , Andersson M. , Nowacka-Woszuk J. , Szczerbal I. , Sosnowski J. , Kopp C. , Cernohorska H. , Rubes J.
Published: September 2008

An AI Ayrshire bull was subjected to cytogenetic examination due to lowered fertility. Preliminary Giemsa staining revealed a normal chromosome complement (60,XY) and G-banding did not allow us to draw a clear conclusion concerning an occurrence of chromosome rearrangement. Testicles were collected at slaughter and synaptonemal complex (SC) analysis revealed a large cross-shaped tetravalent configuration in pachytene spreads. No association between the tetravalent and XY bivalent was observed. Chromosome painting, with the use of bovine whole chromosome painting probes, conjugated with DAPI staining, facilitated a detailed description of the translocation rcp(2;4)(q45;q34). This study shows that post mortem analysis of synaptonemal complexes is a simple and useful tool for the preliminary detection of reciprocal translocation carriers.
The cutthroat trout Y chromosome is conserved with that of rainbow trout
Authors: Alfaqih M.A. , Phillips R.B. , Wheeler P.A. , Thorgaard G.H.
Published: September 2008

Five genetic markers previously shown to be located on the sex chromosomes of rainbow trout (Oncorhynchus mykiss) were tested for linkage with the sex locus of Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) in a genetic cross created from a rainbow × cutthroat male hybrid. We show that the sex locus of both rainbow and cutthroat trout is on the same homologous linkage group. Fluorescence in situ hybridization (FISH) using a probe for the microsatellite marker Omm1665, which maps close to the sex locus of Yellowstone cutthroat trout, was used to identify the Y chromosome of cutthroat trout in the hybrid. The Y chromosome of cutthroat trout is sub-telocentric and lacks a DAPI band found on the short arm of the Y chromosome of some rainbow trout males.
B chromosomes of Puschkinia libanotica are characterized by a reduced level of euchromatic histone H3 methylation marks
Authors: Kumke K. , Jones R.N. , Houben A.
Published: September 2008

Epigenetic marks in the chromosome complement of the liliaceous plant Puschkinia libanotica were studied using immunofluorescence to detect histone modifications. In particular, a comparison was made between the euchromatic and heterochromatic components of supernumerary B chromosomes (Bs) relative to the A chromosomes of the basic diploid set, in order to provide further insights into the enigmatic properties of these ‘genetically silent’ Bs. No differences were found between A and B chromosomes for the heterochromatic dimethylation marks of histone H3 at lysine positions 9 and 27. However, distinctions between A and B chromosomes were revealed for the euchromatic di- and trimethylation marks of histone H3 at lysine 4. The results indicate that the less-transcriptionally active Bs are not marked by an enriched level of heterochromatic histone marks, but rather by a low level of euchromatin-associated histone modifications.
The centromeric satellite of the wedge sole (Dicologoglossa cuneata, Pleuronectiformes) is composed mainly of a sequence motif conserved in other vertebrate centromeric DNAs
Authors: de la Herrán R. , Robles F. , Navas J.I. , López-Flores I. , Herrera M. , Hachero I. , Garrido-Ramos M.A. , Ruiz Rejón C. , Ruiz Rejón M.
Published: September 2008

Here, a new satellite-DNA family is isolated and characterized from wedge sole, Dicologoglossa cuneata Moreau, 1881 (Pleuronectiformes), a fish having a small genome. This satellite-DNA family of sequences was isolated by conventional cloning after digestion of genomic DNA with the DraI restriction enzyme. Repeat units are 171 bp in length with a high AT content (63%). Several runs of consecutive adenines and thymines were found, and concomitantly computer analyses revealed that these regions are prone to acquire stable sequence-directed curvature. Especially remarkable is that the DraI sequences are composed almost entirely of the repetition of up to fourteen 9-bp motifs (T/C)GTC(A/C)AAAA similar to other vertebrate centromeric satellite-DNA sequences. In fact, we demonstrate the origin of this satellite through duplication of this motif plus the addition of a stretch of cytosines. The centromeric location and the presence in this satellite-DNA sequence of not only different vertebrate motifs (CENP-B box, pJα) but also others such as the CDEIII motif of Saccharomyces cerevisiae reveal a possible role in centromere function. All these characteristics provide important information on the origin, function, and the evolution of the centromeric satellite DNAs in wedge sole.
Characterization of internal structure of the nucleolar organizing region in rice (Oryza sativa L.)
Authors: Mizuno H. , Sasaki T. , Matsumoto T.
Published: September 2008

The genomic sequence of the nucleolar organizing region (NOR) in rice has not been characterized fully because of the difficulty in assembling repetitive sequences in silico. Here, we used a cytogenetic approach to elucidate the internal structure of the NOR. We detected one locus of the 18S rRNA genes on ‘Nipponbare’ chromosome. High-resolution fiber-fluorescence in situ hybridization made it possible to visualize each rRNA gene unit in the array of rRNA genes. Signals of pairs of alternating 18S and 25S rRNA genes were detected uniformly along the DNA fiber. Intergenic spacers were shorter than the transcribed region. The rRNA genes were infrequently interrupted. These and previous results based on the sequencing of genome fragments, PCR analysis and Southern blot hybridization suggest that the internal region of the NOR is filled with a uniform array of canonical rRNA genes separated by spacers carrying three 254-bp sub-repeats.
Progress of Cancer Pain Management in Korea
Authors: Lee Jee Yun , Ahn Jin Seok
Published: September 2008

Cancer pain management had received relatively little attention until the late 1990s, when approximately 100,000 new cancer cases and 60,000 cancer deaths occurred each year in Korea. In 2001, a Cancer Pain Management Guideline was prepared for the first time by the Korean Society of Hospice and Palliative Care. This guideline facilitated cancer pain management by health professionals since then. In addition, cancer pain management has been included in the regular curriculum of all medical schools in Korea. The Korean Cancer Pain Assessment Tool, which was developed in 2003, has been accepted as a reliable and valid instrument for assessing cancer pain in Korea. The Korean version of quality of life assessment tools has also been accepted as a useful method. Oral short-acting opioids became available, along with other effective and convenient opioid drugs. The Korean government first published the Cancer Pain Management Guideline for health care professionals in 2004 and expanded the medical reimbursement criteria for cancer pain management, which reflect the government’s support and interest in cancer pain care. The cancer pain surveys conducted in 2001 and 2006 demonstrated a significantly increased patient satisfaction on pain control (37% in 2001, n = 3,006 vs. 42% in 2006, n = 3,737, p = 0.003). Therefore, cancer pain management has been systematically approached both by health professionals as well as the government and resulted in a vast improvement in cancer pain control.
Oxycodone and the Challenge of Neuropathic Cancer Pain: A Review
Authors: Núñez Olarte Juan M.
Published: September 2008

In order to evaluate the potential role of oxycodone in cancer pain management, neuropathic cancer pain was selected as a model for difficult pain syndromes. A nonsystematic, yet exhaustive, review of the literature provided the relevant evidence for the discussion. Ten randomized controlled trials (RCTs) and 5 open-label studies on oxycodone and cancer pain, 3 RCTs and 1 open-label study on oxycodone and neuropathic pain, and 2 RCTs on oxycodone and visceral pain were identified and reviewed. Additionally, 5 basic research studies that contributed to our knowledge of the specific mechanisms of action of oxycodone were also reviewed. Finally, recent evidence-based reviews of RCTs on neuropathic pain were selected (6 reviews), and specific RCTs on neuropathic cancer pain were also identified (2 trials). The review of the literature shows that the management of neuropathic cancer pain has changed dramatically in the last few years thanks to new approaches and novel drugs. The vast majority of these new drugs have been proven to be useful in ‘benign’ neuropathic pain syndromes. The intrinsic difficulties in performing RCTs in cancer pain have traditionally justified the acceptance of drugs already known to be effective in benign neuropathic pain, in spite of insufficient evidence in malignant neuropathic pain. Therefore, a case is made for the development of specific guidelines for the management of both simple and complex cases of neuropathic cancer pain. An example of one of such clinical guidelines is provided, in which the role of oxycodone is particularly relevant given the existing evidence.