bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of a powered bone marrow biopsy device with a manual system: results of a prospective randomised controlled trial
Authors: Bucher Christoph Marcus , Lehmann Thomas , Tichelli André , Tzankov Alexander , Dirnhofer Stephan , Passweg Jakob , Rovó Alicia
Published: October 2012

The diagnostic and clinical usefulness of a powered bone marrow biopsy device (OnControl()) versus a standard manual device (TRAP Hospital System) was studied. Primary endpoints were biopsy quality and patient pain during the procedure. Fifty patients underwent a total of 60 procedures by three expert operators in a randomised stratified fashion. Baseline demographic and clinical parameters were similar in both groups. The usage of conscious sedation, dosage of lidocaine/pethidin was similar between groups. Biopsy quality was rated ‘sufficient for diagnosis’ in 24/30 in the control group and 25/30 in the powered group (p=0.74). Biopsy cylinder length, procedure time (from skin contact of the biopsy needle to placement of the biopsy cylinder in the formalin container) and patient reported pain during the procedure (T1), 15 min after the procedure (T2) and 3–5 days after the procedure (T3) there were comparable between groups. In the small subgroup of patients that did not receive conscious sedation (n=15; manual 6, powered 9) significantly lower median pain scores were observed with the powered system (median pain score 3 vs 7; p=0.015). Patients were satisfied with either device whether sedation was used (sedation: median 9 for both groups, range 3–10 (manual) and 0–10 (powered)) no sedation (median 8 (manual) vs 9 (powered)). In summary bone marrow biopsies taken with the manual or powered device produce similar technical and clinical results. If no conscious sedation is used, pain during the procedure appears to be lower with the powered system. The use of a powered system seems to be justified in selected patients.
Presence of Torque teno sus virus in porcine circovirus type 2‐associated disease in Croatia
Authors: Novosel D. , Lipej Z. , Cubric‐Curik V. , Jungic A.
Published: October 2012

Torque teno virus (TTV) is ubiquitous and species‐specific, and two different TTV species, Torque teno sus virus 1 (TTSuV1) and Torque teno sus virus 2 (TTSuV2), have been described in domestic pigs and wild boars. Whether these two species are involved in clinical cases of porcine circovirus type 2‐associated disease (PCVDs) remains unknown. This study investigates the presence of TTSuV in 85 fetuses, pigs and wild boars infected by PCV2 and affected by PCVDs other than postweaning multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome. It also explores the genetic diversity of identified strains using phylogenetic analysis. The presence or absence of TTSuV was determined in 85 samples of PCV2‐containing organs from 85 infected animals using a specific, one‐step PCR method. A nucleotide distance matrix between sequences was computed to infer phylogeny based on a median‐joining (MJ) network. TTSuV2 showed high prevalence in animals affected by nephropathy and proliferative and necrotising pneumonia (PNP), and both TTSuV1 and TTSuV2 showed high prevalence in wild boars affected by PMWS. TTSuV1 showed low prevalence in animals affected by nephropathy and PNP, and both TTSuV1 and TTSuV2 showed low prevalence in animals with reproductive disorders. MJ network analysis revealed significant genetic diversity among Croatian isolates.
Genetic analysis of Washington State harbor seals (Phoca vitulina richardii) using microsatellites
Authors: Huber H.R. , Dickerson B.R. , Jeffries S.J. , Lambourn D.M.
Published: October 2012

Washington harbor seals ( Phoca vitulina richardii (Gray, 1864)) are currently managed as two stocks: Washington Coastal Stock and Washington Inland Waters Stock. Previous analysis of mitochondrial DNA (mtDNA) in Washington harbor seals showed four geographically and genetically distinct populations. In this study of biparentally inherited nuclear DNA, we analyzed nine microsatellite loci on 482 samples of unweaned pups from nine locations in Washington State and the US–Canadian transboundary waters to determine if there were differences in gene flow between males and females. We found the same four genetically and geographically distinct populations as the analysis of maternally inherited mtDNA: Washington Coast, north Inland Waters, Hood Canal, and south Puget Sound. We recommend that the coastal stock remain as is, but the harbor seals in the Washington Inland Waters should be managed as three distinct populations rather than one.
INFLUENCE OF La2O3 ADDITIONS ON CHEMICAL DURABILITY AND DIELECTRIC PROPERTIES OF BOROALUMINOSILICATE GLASSES
Authors: ZHANG X. H. , YUE Y. L. , WU H. T.
Published: October 2012

Boroaluminosilicate glasses containing La2O3 were prepared by the normal quenching method. The glass transition temperatures (Tg) were measured by differential scanning calorimetry (DSC). The structural role of RO was investigated by nuclear magnetic resonance (NMR). Chemical durability was evaluated by weight losses of glass samples after immersion in HC1 solution. High resolution scanning electron microscopy (HR-SEM) was used to examine the surface micrographs of corroded glass samples. The dielectric constant and tangent loss were measured in the frequency range 10–106 Hz. The results revealed that chemical durability and dielectric properties increased with increasing La2O3 content.
ENTANGLEMENT DYNAMICS IN FINITE QUDIT CHAIN IN CONSISTENT MAGNETIC FIELD
Authors: IVANCHENKO E. A.
Published: October 2012

Based on the Liouville–von Neumann equation, we obtain a closed system of equations for the description of a qutrit or coupled qutrits in an arbitrary, time-dependent, external magnetic field. The dependence of the dynamics on the initial states and the magnetic field modulation is studied analytically and numerically. We compare the relative entanglement measure's dynamics in bi-qudits with permutation particle symmetry. We find the magnetic field modulation which retains the entanglement in the system of two coupled qutrits. Analytical formulae for the entanglement measures in finite chains from two to six qutrits or three quartits are presented.
Hepatocyte-specific deletion of hepatocyte nuclear factor-4α in adult mice results in increased hepatocyte proliferation
Authors: Walesky Chad , Gunewardena Sumedha , Terwilliger Ernest F. , Edwards Genea , Borude Prachi , Apte Udayan
Published: October 2012

Hepatocyte nuclear factor-4α (HNF4α) is known as the master regulator of hepatocyte differentiation. Recent studies indicate that HNF4α may inhibit hepatocyte proliferation via mechanisms that have yet to be identified. Using a HNF4α knockdown mouse model based on delivery of inducible Cre recombinase via an adeno-associated virus 8 viral vector, we investigated the role of HNF4α in the regulation of hepatocyte proliferation. Hepatocyte-specific deletion of HNF4α resulted in increased hepatocyte proliferation. Global gene expression analysis showed that a majority of the downregulated genes were previously known HNF4α target genes involved in hepatic differentiation. Interestingly, ≥500 upregulated genes were associated with cell proliferation and cancer. Furthermore, we identified potential negative target genes of HNF4α, many of which are involved in the stimulation of proliferation. Using chromatin immunoprecipitation analysis, we confirmed binding of HNF4α at three of these genes. Furthermore, overexpression of HNF4α in mouse hepatocellular carcinoma cells resulted in a decrease in promitogenic gene expression and cell cycle arrest. Taken together, these data indicate that, apart from its role in hepatocyte differentiation, HNF4α actively inhibits hepatocyte proliferation by repression of specific promitogenic genes.
Mechanosensitive Cl− secretion in biliary epithelium mediated through TMEM16A
Authors: Dutta Amal K. , Woo Kangmee , Khimji Al-karim , Kresge Charles , Feranchak Andrew P.
Published: October 2012

Bile formation by the liver is initiated by canalicular transport at the hepatocyte membrane, leading to an increase in ductular bile flow. Thus, bile duct epithelial cells (cholangiocytes), which contribute to the volume and dilution of bile through regulated Cl− transport, are exposed to changes in flow and shear force at the apical membrane. The aim of the present study was to determine if fluid flow, or shear stress, is a signal regulating cholangiocyte transport. The results demonstrate that, in human and mouse biliary cells, fluid flow, or shear, increases Cl− currents and identify TMEM16A, a Ca2+-activated Cl− channel, as the operative channel. Furthermore, activation of TMEM16A by flow is dependent on PKCα through a process involving extracellular ATP, binding purinergic P2 receptors, and increases in intracellular Ca2+ concentration. These studies represent the initial characterization of mechanosensitive Cl− currents mediated by TMEM16A. Identification of this novel mechanosensitive secretory pathway provides new insight into bile formation and suggests new therapeutic targets to enhance bile formation in the treatment of cholestatic liver disorders.
Conditional knockout of the Slc5a6 gene in mouse intestine impairs biotin absorption
Authors: Ghosal Abhisek , Lambrecht Nils , Subramanya Sandeep B. , Kapadia Rubina , Said Hamid M.
Published: October 2012

The Slc5a6 gene expresses a plasma membrane protein involved in the transport of the water-soluble vitamin biotin; the transporter is commonly referred to as the sodium-dependent multivitamin transporter (SMVT) because it also transports pantothenic acid and lipoic acid. The relative contribution of the SMVT system toward carrier-mediated biotin uptake in the native intestine in vivo has not been established. We used a Cre/lox technology to generate an intestine-specific (conditional) SMVT knockout (KO) mouse model to address this issue. The KO mice exhibited absence of expression of SMVT in the intestine compared with sex-matched littermates as well as the expected normal SMVT expression in other tissues. About two-thirds of the KO mice died prematurely between the age of 6 and 10 wk. Growth retardation, decreased bone density, decreased bone length, and decreased biotin status were observed in the KO mice. Microscopic analysis showed histological abnormalities in the small bowel (shortened villi, dysplasia) and cecum (chronic active inflammation, dysplasia) of the KO mice. In vivo (and in vitro) transport studies showed complete inhibition in carrier-mediated biotin uptake in the intestine of the KO mice compared with their control littermates. These studies provide the first in vivo confirmation in native intestine that SMVT is solely responsible for intestinal biotin uptake. These studies also provide evidence for a casual association between SMVT function and normal intestinal health.
Identification of L- and T-type Ca2+channels in rat cerebral arteries: role in myogenic tone development
Authors: El-Rahman Rasha R. Abd , Harraz Osama F. , Brett Suzanne E. , Anfinogenova Yana , Mufti Rania E. , Goldman Daniel , Welsh Donald G.
Published: October 2012

L-type Ca2+channels are broadly expressed in arterial smooth muscle cells, and their voltage-dependent properties are important in tone development. Recent studies have noted that these Ca2+channels are not singularly expressed in vascular tissue and that other subtypes are likely present. In this study, we ascertained which voltage-gated Ca2+channels are expressed in rat cerebral arterial smooth muscle and determined their contribution to the myogenic response. mRNA analysis revealed that the α1-subunit of L-type (Cav1.2) and T-type (Cav3.1 and Cav3.2) Ca2+channels are present in isolated smooth muscle cells. Western blot analysis subsequently confirmed protein expression in whole arteries. With the use of patch clamp electrophysiology, nifedipine-sensitive and -insensitive Ba2+currents were isolated and each were shown to retain electrical characteristics consistent with L- and T-type Ca2+channels. The nifedipine-insensitive Ba2+current was blocked by mibefradil, kurtoxin, and efonidpine, T-type Ca2+channel inhibitors. Pressure myography revealed that L-type Ca2+channel inhibition reduced tone at 20 and 80 mmHg, with the greatest effect at high pressure when the vessel is depolarized. In comparison, the effect of T-type Ca2+channel blockade on myogenic tone was more limited, with their greatest effect at low pressure where vessels are hyperpolarized. Blood flow modeling revealed that the vasomotor responses induced by T-type Ca2+blockade could alter arterial flow by ∼20–50%. Overall, our findings indicate that L- and T-type Ca2+channels are expressed in cerebral arterial smooth muscle and can be electrically isolated from one another. Both conductances contribute to myogenic tone, although their overall contribution is unequal.
High-throughput screening of drug-binding dynamics to HERG improves early drug safety assessment
Authors: Di Veroli Giovanni Y. , Davies Mark R. , Zhang Henggui , Abi-Gerges Najah , Boyett Mark R.
Published: October 2012

The use of computational models to predict drug-induced changes in the action potential (AP) is a promising approach to reduce drug safety attrition but requires a better representation of more complex drug-target interactions to improve the quantitative prediction. The blockade of the human ether-a-go-go-related gene (HERG) channel is a major concern for QT prolongation and Torsade de Pointes risk. We aim to develop quantitative in-silico AP predictions based on a new electrophysiological protocol (suitable for high-throughput HERG screening) and mathematical modeling of ionic currents. Electrophysiological recordings using the IonWorks device were made from HERG channels stably expressed in Chinese hamster ovary cells. A new protocol that delineates inhibition over time was applied to assess dofetilide, cisapride, and almokalant effects. Dynamic effects displayed distinct profiles for these drugs compared with concentration-effects curves. Binding kinetics to specific states were identified using a new HERG Markov model. The model was then modified to represent the canine rapid delayed rectifier K+ current at 37°C and carry out AP predictions. Predictions were compared with a simpler model based on conductance reduction and were found to be much closer to experimental data. Improved sensitivity to concentration and pacing frequency variables was obtained when including binding kinetics. Our new electrophysiological protocol is suitable for high-throughput screening and is able to distinguish drug-binding kinetics. The association of this protocol with our modeling approach indicates that quantitative predictions of AP modulation can be obtained, which is a significant improvement compared with traditional conductance reduction methods.
Taming the “sleeping giant”: the role of endothelin-1 in the regulation of skeletal muscle blood flow and arterial blood pressure during exercise
Authors: Barrett-O'Keefe Zachary , Ives Stephen J. , Trinity Joel D. , Morgan Garrett , Rossman Matthew J. , Donato Anthony J. , Runnels Sean , Morgan David E. , Gmelch Benjamin S. , Bledsoe Amber D. , Richardson Russell S. , Wray D. Walter
Published: October 2012

The cardiovascular response to exercise is governed by a combination of vasodilating and vasoconstricting influences that optimize exercising muscle perfusion while protecting mean arterial pressure (MAP). The degree to which endogenous endothelin (ET)-1, the body's most potent vasoconstrictor, participates in this response is unknown. Thus, in eight young (24 ± 2 yr), healthy volunteers, we examined leg blood flow, MAP, tissue oxygenation, heart rate, leg arterial-venous O2 difference, leg O2 consumption, pH, and net ET-1 and lactate release at rest and during knee extensor exercise (0, 5, 10, 15, 20, and 30 W) before and after an intra-arterial infusion of BQ-123 [ET subtype A (ETA) receptor antagonist]. At rest, BQ-123 did not evoke a change in leg blood flow or MAP. During exercise, net ET-1 release across the exercising leg increased approximately threefold. BQ-123 increased leg blood flow by ∼20% across all work rates (changes of 113 ± 76, 176 ± 83, 304 ± 108, 364 ± 130, 502 ± 117, and 570 ± 178 ml/min at 0, 5, 10, 15, 20, and 30 W, respectively) and attenuated the exercise-induced increase in MAP by ∼6%. The increase in leg blood flow was accompanied by a ∼9% increase in leg O2 consumption with an unchanged arterial-venous O2 difference and deoxyhemoglobin, suggesting a decline in intramuscular efficiency after ETA receptor blockade. Together, these findings identify a significant role of the ET-1 pathway in the cardiovascular response to exercise, implicating vasoconstriction via the ETA receptor as an important mechanism for both the restraint of blood flow in the exercising limb and maintenance of MAP in healthy, young adults.
Pkd2 mesenteric vessels exhibit a primary defect in endothelium-dependent vasodilatation restored by rosiglitazone
Authors: Brookes Zoë L. S. , Ruff Lewis , Upadhyay Viralkumar S. , Huang Linghong , Prasad Sony , Solanky Tirupa , Nauli Surya M. , Ong Albert C. M.
Published: October 2012

Patients with autosomal dominant polycystic kidney disease have a high prevalence of hypertension and structural vascular abnormalities, such as intracranial aneurysms. Hypertension can develop in childhood and often precedes a significant reduction in the glomerular filtration rate. The major aim of this study was to investigate whether a primary endothelial defect or a vascular smooth muscle (VSM) defect was present in murine polycystic kidney disease (Pkd)2 heterozygous mesenteric vessels before the development of renal failure or hypertension. Using pressure myography, we observed a marked defect in ACh-stimulated endothelium-dependent vasodilatation in Pkd2 arterioles. In contrast, Pkd2 vessels responded normally to sodium nitroprusside, phenylephrine, KCl, and pressure, indicating unaltered VSM-dependent responses. Pretreatment with the peroxisome proliferator-activated receptor-γ agonist rosiglitazone significantly restored ACh-dependent vasodilation in Pkd2 mice. Isolated heterozygous Pkd2 endothelial cells displayed normal ACh-stimulated Ca2+and nitric oxide production. However, isolated Pkd2 heterozygous VSM cells displayed basal increases in superoxide and sodium nitroprusside-stimulated peroxynitrite formation, which were both suppressed by rosiglitazone. Furthermore, we observed a defective response of Pkd2 mesenteric venules to ACh in vivo, which was more marked after ischemia-reperfusion injury. In conclusion, the results of our study suggest that the defect in vasodilatation in Pkd2 heterozygous vessels is primarily due to a reduction in nitric bioavailability secondary to increased vascular oxidative stress. The ability of rosiglitazone to correct this phenotype suggests that this defect is potentially reversible in patients with autosomal dominant polycystic kidney disease.
AMP kinase activation improves angiogenesis in pulmonary artery endothelial cells with in utero pulmonary hypertension
Authors: Teng Ru-Jeng , Du Jianhai , Afolayan Adeleye J. , Eis Annie , Shi Yang , Konduri Girija G.
Published: October 2012

Pulmonary artery endothelial cells (PAEC) isolated from fetal lambs with in utero pulmonary hypertension (IPH) have phenotypical changes that lead to increased reactive oxygen species (ROS) formation and impaired angiogenesis. AMP-activated protein kinase (AMPK) is known to be activated by ROS, which is expected to help angiogenesis in IPH-PAEC. The objectives of this study were to investigate AMPK responses in IPH and its role in angiogenesis. We observed that, compared with control PAEC, IPH-PAEC have decreased phosphorylation of AMPKα catalytic subunit and AMPK downstream enzymes, indicating a decrease in AMPK activity. In addition, the expression of AMPK kinases is decreased, and protein phosphatase 2 is increased in IPH-PAEC, potentially contributing to the decreased AMPK activation. Metformin, an AMPK activator, improved IPH-PAEC angiogenesis while increasing endothelial NO synthase (eNOS) serine1179 phosphorylation and decreasing the eNOS-caveolin-1 association. Metformin also increased MnSOD activity and the expression of both eNOS and MnSOD. The increase in angiogenesis by Metformin is abolished by pretreatment with AMPK inhibitor, Compound C. Expression of vascular endothelial growth factor (VEGF) and platelet-derived growth factor β (PDGFβ) are decreased in IPH-PAEC compared with control PAEC and were not altered by Metformin. These data indicate that Metformin improves angiogenesis through mechanisms independent of these angiogenic factors. In conclusion, activation of AMPK restores angiogenesis and increases the bioavailability of nitric oxide in IPH. Whether Metformin is beneficial in the management of pulmonary hypertension requires further investigation.
Pretreatment with brain natriuretic peptide reduces skeletal muscle mitochondrial dysfunction and oxidative stress after ischemia-reperfusion
Authors: Talha Samy , Bouitbir Jamal , Charles Anne-Laure , Zoll Joffrey , Goette-Di Marco Paola , Meziani Ferhat , Piquard François , Geny Bernard
Published: October 2012

Brain natriuretic peptide (BNP) reduces the extent of myocardial infarction. We aimed to determine whether BNP may reduce skeletal muscle mitochondrial dysfunctions and oxidative stress through mitochondrial KATP(mKATP) channel opening after ischemia-reperfusion (IR). Wistar rats were assigned to four groups: sham, 3-h leg ischemia followed by 2-h reperfusion (IR), pretreatment with BNP, and pretreatment with 5-hydroxydecanoic acid, an mKATPchannel blocker, before BNP. Mitochondrial respiratory chain complex activities of gastrocnemius muscles were determined using glutamate-malate (V̇max), succinate (V̇succ), and N, N, N′, N′-tetramethyl- p-phenylenediamine dihydrochloride ascorbate (V̇TMPD/asc). Apoptosis (Bax-to-Bcl2 mRNA ratio and caspase-3 activity) and oxidative stress (dihydroethidium staining) were also assessed. Compared with the sham group, IR significantly decreased V̇max, reflecting complex I, II, and IV activities (−36%, 3.7 ± 0.3 vs. 5.8 ± 0.2 μmol O2·min−1·g dry wt−1, P < 0.01), and V̇TMPD/asc, reflecting complex IV activity (−37%, 8.6 ± 0.8 vs. 13.7 ± 0.9 μmol O2·min−1·g dry wt−1, P < 0.01). IR increased Bax-to-Bcl2 ratio (+57%, 1.1 ± 0.1 vs. 0.7 ± 0.1, P < 0.05) and oxidative stress (+45%, 9,067 ± 935 vs. 6,249 ± 723 pixels, P > 0.05). BNP pretreatment reduced the above alterations, increasing V̇max(+38%, P < 0.05) and reducing Bax-to-Bcl2 ratio (−55%, P < 0.01) and oxidative stress (−58%, P < 0.01). BNP protection against deleterious IR effects on skeletal muscles was abolished by 5-hydroxydecanoic acid. Caspase-3 activities did not change significantly. Conversely, BNP injected during ischemia failed to protect against muscle injury. In addition to maintaining the activity of mitochondrial respiratory chain complexes and possibly decreasing apoptosis, pretreatment with BNP protects skeletal muscle against IR-induced lesions, most likely by decreasing excessive production of radical oxygen species and opening mKATPchannels.
Heart failure with preserved ejection fraction: chronic low-intensity interval exercise training preserves myocardial O2 balance and diastolic function
Authors: Marshall Kurt D. , Muller Brittany N. , Krenz Maike , Hanft Laurin M. , McDonald Kerry S. , Dellsperger Kevin C. , Emter Craig A.
Published: October 2012

We have previously reported chronic low-intensity interval exercise training attenuates fibrosis, impaired cardiac mitochondrial function, and coronary vascular dysfunction in miniature swine with left ventricular (LV) hypertrophy (Emter CA, Baines CP. Am J Physiol Heart Circ Physiol 299: H1348–H1356, 2010; Emter CA, et al. Am J Physiol Heart Circ Physiol 301: H1687–H1694, 2011). The purpose of this study was to test two hypotheses: 1) chronic low-intensity interval training preserves normal myocardial oxygen supply/demand balance; and 2) training-dependent attenuation of LV fibrotic remodeling improves diastolic function in aortic-banded sedentary, exercise-trained (HF-TR), and control sedentary male Yucatan miniature swine displaying symptoms of heart failure with preserved ejection fraction. Pressure-volume loops, coronary blood flow, and two-dimensional speckle tracking ultrasound were utilized in vivo under conditions of increasing peripheral mean arterial pressure and β-adrenergic stimulation 6 mo postsurgery to evaluate cardiac function. Normal diastolic function in HF-TR animals was characterized by prevention of increased time constant of isovolumic relaxation, normal LV untwisting rate, and enhanced apical circumferential and radial strain rate. Reduced fibrosis, normal matrix metalloproteinase-2 and tissue inhibitors of metalloproteinase-4 mRNA expression, and increased collagen III isoform mRNA levels ( P < 0.05) accompanied improved diastolic function following chronic training. Exercise-dependent improvements in coronary blood flow for a given myocardial oxygen consumption ( P < 0.05) and cardiac efficiency (stroke work to myocardial oxygen consumption, P < 0.05) were associated with preserved contractile reserve. LV hypertrophy in HF-TR animals was associated with increased activation of Akt and preservation of activated JNK/SAPK. In conclusion, chronic low-intensity interval exercise training attenuates diastolic impairment by promoting compliant extracellular matrix fibrotic components and preserving extracellular matrix regulatory mechanisms, preserves myocardial oxygen balance, and promotes a physiological molecular hypertrophic signaling phenotype in a large animal model resembling heart failure with preserved ejection fraction.
Separating in vivo mechanical stimuli for postpneumonectomy compensation: physiological assessment
Authors: Dane D. Merrill , Yilmaz Cuneyt , Estrera Aaron S. , Hsia Connie C. W.
Published: October 2012

Following right pneumonectomy (PNX), the remaining lung expands and its perfusion doubles. Tissue and microvascular mechanical stresses are putative stimuli for initiating compensatory lung growth and remodeling, but their relative contributions to overall compensation remain uncertain. To temporally isolate the stimuli related to post-PNX lung expansion (parenchyma deformation) from those related to the sustained increase in perfusion (microvascular distention and shear), we replaced the right lung of adult dogs with a custom-shaped inflated prosthesis. Following stabilization of perfusion and wound healing 4 mo later, the prosthesis was either acutely deflated (DEF group) or kept inflated (INF group). Physiological studies were performed pre-PNX, 4 mo post-PNX (inflated prosthesis, INF1), and again 4 mo postdeflation (DEF) compared with controls with simultaneous INF prosthesis (INF2). Perfusion to the remaining lung increased ∼76–113% post-PNX (INF1 and INF2) and did not change postdeflation. Post-PNX (INF prosthesis) end-expiratory lung volume (EELV) and lung and membrane diffusing capacities (DlCOand DmCO) at a given perfusion were 25–40% below pre-PNX baseline. In the INF group EELV, DlCOand DmCOremained stable or declined slightly with time. In contrast, all of these parameters increased significantly after deflation and were 157%, 26%, and 47%, respectively, above the corresponding control values (INF2). Following delayed deflation, lung expansion accounted for 44%-48% of total post-PNX compensatory increase in exercise DlCOand peak O2uptake; the remainder fraction is likely attributable to the increase in perfusion. Results suggest that expansion-related parenchyma mechanical stress and perfusion-related microvascular stress contribute in equal proportions to post-PNX alveolar growth and remodeling.
Loss of 53BP1 Causes PARP Inhibitor Resistance in Brca1-Mutated Mouse Mammary Tumors
Authors: Jaspers Janneke E. , Kersbergen Ariena , Boon Ute , Sol Wendy , van Deemter Liesbeth , Zander Serge A. , Drost Rinske , Wientjens Ellen , Ji Jiuping , Aly Amal , Doroshow James H. , Cranston Aaron , Martin Niall M.B. , Lau Alan , O'Connor Mark J. , Ganesan Shridar , Borst Piet , Jonkers Jos , Rottenberg Sven
Published: October 2012

Inhibition of PARP is a promising therapeutic strategy for homologous recombination–deficient tumors, such as BRCA1-associated cancers. We previously reported that BRCA1-deficient mouse mammary tumors may acquire resistance to the clinical PARP inhibitor (PARPi) olaparib through activation of the P-glycoprotein drug efflux transporter. Here, we show that tumor-specific genetic inactivation of P-glycoprotein increases the long-term response of BRCA1-deficient mouse mammary tumors to olaparib, but these tumors eventually developed PARPi resistance. In a fraction of cases, this resistance is caused by partial restoration of homologous recombination due to somatic loss of 53BP1. Importantly, PARPi resistance was minimized by long-term treatment with the novel PARP inhibitor AZD2461, which is a poor P-glycoprotein substrate. Together, our data suggest that restoration of homologous recombination is an important mechanism for PARPi resistance in BRCA1-deficient mammary tumors and that the risk of relapse of BRCA1-deficient tumors can be effectively minimized by using optimized PARP inhibitors.

Significance: In this study, we show that loss of 53BP1 causes resistance to PARP inhibition in mouse mammary tumors that are deficient in BRCA1. We hypothesize that low expression or absence of 53BP1 also reduces the response of patients with BRCA1-deficient tumors to PARP inhibitors. Cancer Discov; 3(1); 68–81. ©2012 AACR.

See related commentary by Fojo and Bates, p. 20

This article is highlighted in the In This Issue feature, p. 1
Oncogenic and Wild-type Ras Play Divergent Roles in the Regulation of Mitogen-Activated Protein Kinase Signaling
Authors: Young Amy , Lou David , McCormick Frank
Published: October 2012

H-Ras, K-Ras, and N-Ras regulate cellular growth and survival and are often activated by somatic mutation in human tumors. Although oncogenic lesions occur in a single Ras isoform within individual tumors, it is unclear whether the remaining wild-type isoforms play supporting roles in tumor growth. Here, we show that oncogenic and wild-type Ras isoforms play independent and nonredundant roles within the cell. Oncogenic Ras regulates basal effector pathway signaling, whereas wild-type Ras mediates signaling downstream of activated receptor tyrosine kinases (RTK). We show that both are necessary for exponential growth of Ras-mutant cell lines. Furthermore, we show that oncogenic Ras desensitizes signaling from EGF receptor (EGFR). Depletion of oncogenic Ras with siRNA oligonucleotides relieves this negative feedback, leading to the hyperactivation of EGFR and wild-type Ras signaling. Consistent with this model, combining oncogenic Ras depletion with EGFR inhibition potently increases cell death.

Significance: The results of this study highlight a novel role for wild-type Ras signaling in cancer cells harboring oncogenic RAS mutations. Furthermore, these findings reveal that therapeutically targeting oncogenic Ras signaling alone may be ineffective owing to feedback activation of RTKs, and suggest that blocking upstream RTKs in combination with downstream effector pathways may be beneficial in the treatment of Ras-mutant tumors. Cancer Discov; 3(1); 112–23. ©2012 AACR.

See related commentary by Hayes and Der, p. 24

This article is highlighted in the In This Issue feature, p. 1
Endothelial Lipase Activity Predicts High-Density Lipoprotein Catabolism in Hemodialysis
Authors: Miksztowicz Veronica , McCoy Mary G. , Schreier Laura , Cacciagiú Leonardo , Elbert Alicia , Gonzalez Ana Inés , Billheimer Jeffrey , Eacho Patrick , Rader Daniel J. , Berg Gabriela
Published: October 2012

Objective—

A novel phospholipase assay was used to measure for the first time the behavior of endothelial and hepatic phospholipase activities in postheparin human plasma of hemodialyzed patients and its relationship with atherogenic and antiatherogenic lipoprotein levels.

Methods and Results—

Endothelial and hepatic phospholipase activity was assessed in a total SN1-specific phospholipase assay, using (1-decanoylthio-1-deoxy-2-decanoyl-sn-glycero-3-phosphoryl) ethylene glycol as the substrate. Hemodialyzed patients presented lower values of total and hepatic phospholipase activity than controls: 4.4 (1.9–9.0) versus 7.5 (3.6–18.0) and 2.6 (0.7–6.2) versus 6.6 (1.3–15.2) μmol of fatty acid released per milliliter of postheparin plasma per hour, respectively (
P
<0.001); however, endothelial lipase (EL) phospholipase activity was increased in patients: 1.7 (0.8–3.0) versus 1.1 (0.1–2.7) μmol of fatty acid released per milliliter of postheparin plasma per hour (
P
=0.008). EL was negatively associated with high-density lipoprotein (HDL)-cholesterol (
r
=–0.427;
P
=0.001), and apolipoprotein A-I levels, total phospholipase, and hepatic lipase activity were directly associated with low-density lipoprotein-cholesterol and apolipoprotein B. The association of EL and HDL-cholesterol remained significant when adjusting for waist circumference (β=–0.26;
P
=0.05), and the effect of hepatic lipase on low-density lipoprotein-cholesterol continued after adjusting for age (β=0.46;
P
= 0.001).

Conclusion—

Our results support the hypothesis that EL is the predominant enzyme responsible for lipolytic catabolism of HDLs in hemodialyzed patients and resolve the apparent paradox observed between low hepatic lipase activity and decreased HDL-cholesterol levels observed in these patients. In addition, the ability to assess total hepatic lipase and EL phospholipase activity in plasma will increase our knowledge of the mechanisms involved in controlling HDL levels and cardiovascular risk in hemodialyzed patients, as well as other populations with low levels of HDL-cholesterol.
Inflammatory Cytokines Promote Mesenchymal Transformation in Embryonic and Adult Valve Endothelial Cells
Authors: Mahler Gretchen J. , Farrar Emily J. , Butcher Jonathan T.
Published: October 2012

Objective—

Inflammatory activation of valve endothelium is an early phase of aortic valve disease pathogenesis, but subsequent mechanisms are poorly understood. Adult valve endothelial cells retain the developmental ability to undergo endothelial-to-mesenchymal transformation (EndMT), but a biological role has not been established. Here, we test whether and how inflammatory cytokines (tumor necrosis factor-α and interleukin-6) regulate EndMT in embryonic and adult valve endothelium.

Methods and Results—

Using in vitro 3-dimensional collagen gel culture assays with primary cells, we determined that interleukin-6 and tumor necrosis factor-α induce EndMT and cell invasion in dose-dependent manners. Inflammatory-EndMT occurred through an Akt/nuclear factor-κB–dependent pathway in both adult and embryonic stages. In embryonic valves, inflammatory-EndMT required canonical transforming growth factor-β signaling through activin receptor-like kinases 2 and 5 to drive EndMT. In adult valve endothelium, however, inflammatory-induced EndMT still occurred when activin receptor-like kinases 2 and 5 signaling was blocked. Inflammatory receptor gene expression was significantly upregulated in vivo during embryonic valve maturation. Endothelial-derived mesenchymal cells expressing activated nuclear factor-κB were found distal to calcific lesions in diseased human aortic valves.

Conclusion—

Inflammatory cytokine–induced EndMT in valve endothelium is present in both embryonic and adult stages, acting through Akt/nuclear factor-κB, but differently using transforming growth factor-β signaling. Molecular signatures of valve EndMT may be important diagnostic and therapeutic targets in early valve disease.
Lipid Phosphate Phosphatase 3 Negatively Regulates Smooth Muscle Cell Phenotypic Modulation to Limit Intimal Hyperplasia
Authors: Panchatcharam Manikandan , Miriyala Sumitra , Salous Abdelghaffar , Wheeler Jessica , Dong Anping , Mueller Paul , Sunkara Manjula , Escalante-Alcalde Diana , Morris Andrew J. , Smyth Susan S.
Published: October 2012

Objective—

The lipid phosphate phosphatase 3 (LPP3) degrades bioactive lysophospholipids, including lysophosphatidic acid and sphingosine-1-phosphate, and thereby terminates their signaling effects. Although emerging evidence links lysophosphatidic acid to atherosclerosis and vascular injury responses, little is known about the role of vascular LPP3. The goal of this study was to determine the role of LPP3 in the development of vascular neointima formation and smooth muscle cells (SMC) responses.

Methods and Results—

We report that LPP3 is expressed in vascular SMC after experimental arterial injury. Using gain- and loss-of-function approaches, we establish that a major function of LPP3 in isolated SMC cells is to attenuate proliferation (extracellular signal-regulated kinases) activity, Rho activation, and migration in response to serum and lysophosphatidic acid. These effects are at least partially a consequence of LPP3-catalyzed lysophosphatidic acid hydrolysis. Mice with selective inactivation of LPP3 in SMC display an exaggerated neointimal response to injury.

Conclusion—

Our observations suggest that LPP3 serves as an intrinsic negative regulator of SMC phenotypic modulation and inflammation after vascular injury, in part, by regulating lysophospholipid signaling. These findings may provide a mechanistic link to explain the association between a
PPAP2B
polymorphism and coronary artery disease risk.
Cardiotoxic and Cardioprotective Features of Chronic β-Adrenergic Signaling
Authors: Zhang Xiaoying , Szeto Christopher , Gao Erhe , Tang Mingxin , Jin Jianguo , Fu Qin , Makarewich Catherine , Ai Xiaojie , Li Ying , Tang Allen , Wang Jenny , Gao Hui , Wang Fang , Ge Xinyi Joy , Kunapuli Satya P. , Zhou Lin , Zeng Chunyu , Xiang Kevin Yang , Chen Xiongwen
Published: October 2012

Rationale:

In the failing heart, persistent β-adrenergic receptor activation is thought to induce myocyte death by protein kinase A (PKA)-dependent and PKA-independent activation of calcium/calmodulin-dependent kinase II. β-adrenergic signaling pathways also are capable of activating cardioprotective mechanisms.

Objective:

This study used a novel PKA inhibitor peptide to inhibit PKA activity to test the hypothesis that β-adrenergic receptor signaling causes cell death through PKA-dependent pathways and cardioprotection through PKA-independent pathways.

Methods and Results:

In PKA inhibitor peptide transgenic mice, chronic isoproterenol failed to induce cardiac hypertrophy, fibrosis, and myocyte apoptosis, and decreased cardiac function. In cultured adult feline ventricular myocytes, PKA inhibition protected myocytes from death induced by β1-adrenergic receptor agonists by preventing cytosolic and sarcoplasmic reticulum Ca
2+
overload and calcium/calmodulin-dependent kinase II activation. PKA inhibition revealed a cardioprotective role of β-adrenergic signaling via cAMP/exchange protein directly activated by cAMP/Rap1/Rac/extracellular signal-regulated kinase pathway. Selective PKA inhibition causes protection in the heart after myocardial infarction that was superior to β-blocker therapy.

Conclusions:

These results suggest that selective block of PKA could be a novel heart failure therapy.
Interobserver Agreement of ASPECT Score Distribution for Noncontrast CT, CT Angiography, and CT Perfusion in Acute Stroke
Authors: Finlayson Olga , John Verity , Yeung Robert , Dowlatshahi Dar , Howard Peter , Zhang Liying , Swartz Rick , Aviv Richard I.
Published: October 2012

Background and Purpose—

The Alberta Stroke program early CT score (ASPECTS) is a semiquantative scale for estimating extent and distribution of early ischemic changes within the MCA territory in the acute stroke setting. Good interobserver agreement of total ASPECTS is demonstrated for noncontrast CT (NCCT) and other imaging modalities. Our purpose is to assess interobserver agreement for individual ASPECTS regions for different imaging modalities.

Methods—

One hundred and eighty-one consecutive patients presenting with acute stroke symptoms within 4.5 hours of onset were included. Four readers assigned total and individual ASPECTS for NCCT, CT angiography source images (CTA-SI), and CTP maps of cerebral blood volume (CTP-CBV). Interobserver agreement was assessed by measuring internal consistency and concordance of total and individual ASPECTS using Cronbach’s α and intraclass correlation coefficient, respectively.

Results—

Total ASPECTS demonstrated very good concordance and internal consistency for all 3 modalities. Intraclass correlation coefficient and Cronbach’s α were 0.834 and 0.859 for NCCT, 0.876 and 0.894 for CTA, and 0.903 and 0.911 for CTP-CBV, respectively. Performance for individual ASPECTS regions was inferior to total ASPECTS, but incremental improvement in interobserver reliability was demonstrated for NCCT, CTA-SI, and CTP-CBV, respectively. Highest concordance was shown for caudate, lentiform, and M1–M3, whereas performance for internal capsule and M4–M6 was poorer.

Conclusions—

CTP-CBV demonstrates the highest interobserver agreement for individual ASPECTS regions.
Baseline Smoking Status and the Long-Term Risk of Death or Nonfatal Vascular Event in People with Stroke
Authors: Kim Joosup , Gall Seana L. , Dewey Helen M. , Macdonell Richard A. L. , Sturm Jonathan W. , Thrift Amanda G.
Published: October 2012

Background and Purpose—

Smoking may exacerbate the risk of death or further vascular events in those with stroke, but data are limited.

Methods—

1589 cases of first-ever and recurrent stroke were recruited between 1996 and 1999 from a defined geographical region in North East Melbourne. Both hospital and nonhospital cases were included. Over a 10-year period, all deaths, recurrent stroke events, and acute myocardial infarctions that were reported at follow-up interviews were validated using medical records. Cox proportional hazards regression was used to assess the association between baseline smoking status (never, ex, and current) and outcome (death, acute myocardial infarction, or recurrent stroke).

Results—

Patients who were current smokers (Hazard Ratio [HR], 1.30; 95% Confidence Interval [CI], 1.06–1.60;
P
=0.012) at the time of their stroke had poorer outcome when compared with those who had never smoked. Among those who survived the first 28 days of stroke, current smokers (HR, 1.42; 95% CI, 1.13–1.78;
P
<0.003) and ex-smokers (HR, 1.18; 95% CI, 1.01–1.39;
P
=0.039) at baseline had poorer outcome than those who had never smoked. Current smokers also had a greater risk of recurrent events than past smokers (HR, 1.23; 95% CI, 1.00–1.50;
P
=0.050).

Conclusions—

Patients who smoked at the time of their stroke or had smoked before their stroke had greater risk of death or recurrent vascular events when compared with patients who were never smokers. There are benefits of smoking cessation, with ex-smokers appearing to have a lesser risk of recurrent vascular events than current smokers.
Decadal Response of the Kuroshio Extension Jet to Rossby Waves: Observation and Thin-Jet Theory*
Authors: Sasaki Yoshi N. , Minobe Shoshiro , Schneider Niklas
Published: October 2012

This study examines interannual to decadal variability of the Kuroshio Extension (KE) jet using satellite altimeter observations from 1993 to 2010. The leading empirical orthogonal function (EOF) mode of sea level variability in the KE region represents the meridional shift of the KE jet, followed by its strength changes with a few month lag. This shift of the KE jet lags atmospheric fluctuations over the eastern North Pacific by about three years. Broad sea level anomalies (SLAs) emerge in the eastern North Pacific 3–4 years before the upstream KE jet shift, and propagate westward along the KE jet axis. In the course of the propagation, the meridional scale of the SLAs gradually narrows, and their amplitude increases. This westward propagation of SLAs with a speed of about 5 cm s−1 is attributed to the westward propagation of the meridional shift of the jet, consistent with the thin-jet theory, whose importance has been suggested by previous numerical studies. In addition, the westward-propagating signals tend to conserve their quasigeostrophic potential vorticity anomaly, which may explain the characteristic changes of SLAs during the propagation. After the westward-propagating signals of positive (negative) SLAs reach at the east coast of Japan, the upstream KE jet strengthens (weakens) associated with the strength changes of the northern and southern recirculation gyres. Interestingly, this strength change of the KE jet propagates eastward with a speed of about 6 cm s−1, suggesting an importance of advection by the current.
The Erotic Transference: Dream or Delusion?
Authors: De Masi Franco
Published: October 2012

The erotic transference can be seen as the Janus face of clinical work in psychoanalysis: it may either arise out of the positive emotions necessary for the building of new shared realities, or be fueled by falsified and distorted constructions. In the former case, the erotic transference expresses the capacity to anticipate, or “dream,” the emotional relationship with the object—which is why Freud valued its transformative aspect as one of the “forces impelling [the patient] to . . . make changes”—whereas in the latter it is equivalent to a flight from psychic reality and may be imperceptibly transformed into an actual delusion.
Gene Expression Dynamics during Diabetic Periodontitis
Authors: Andriankaja O.M. , Galicia J. , Dong G. , Xiao W. , Alawi F. , Graves D.T.
Published: October 2012

Diabetes impairs the resolution of periodontal inflammation. We explored pathways altered by inflammation in the diabetic periodontium by using ligatures to induce periodontitis in type-2 diabetic Goto-Kakizaki rats. Ligatures were removed after 7 days, and rats were then treated with TNF inhibitor (pegsunercept) or vehicle alone and euthanized 4 days later. RNA was extracted from periodontal tissue, examined by mRNA profiling, and further analyzed by functional criteria. We found that 1,754 genes were significantly up-regulated and 1,243 were down-regulated by pegsunercept (p < 0.05). Functional analysis revealed up-regulation of neuron-associated and retina-associated gene clusters as well as those related to cell activity and signaling. Others were down-regulated by TNF inhibition and included genes associated with host defense, apoptosis, cell signaling and activity, and coagulation/hemostasis/complement. For selected genes, findings with microarray and rt-PCR agreed. PPAR-α was investigated further by immunohistochemistry due to its anti-inflammatory function and was found to be up-regulated in the gingiva during the resolution of periodontal inflammation and suppressed by diabetes. The results indicate that diabetes-enhanced inflammation both up- and down-regulates genes involved in cellular activity and cell signaling, while it predominantly up-regulates genes involved in the host response, apoptosis, and coagulation/homeostasis/complement and down-regulates mRNA levels of neuron, retina, and energy/metabolism-associated genes.