bluuebunny/crossref_metadata_2025 huggingface dataset:
Meal patterns, satiety, and food choice in a rat model of Roux-en-Y gastric bypass surgery
Authors: Zheng Huiyuan , Shin Andrew C. , Lenard Natalie R. , Townsend R. Leigh , Patterson Laurel M. , Sigalet David L. , Berthoud Hans-Rudolf
Published: September 2009

Gastric bypass surgery efficiently and lastingly reduces excess body weight and reverses type 2 diabetes in obese patients. Although increased energy expenditure may also play a role, decreased energy intake is thought to be the main reason for weight loss, but the mechanisms involved are poorly understood. Therefore, the aim of this study was to characterize the changes in ingestive behavior in a rat model of Roux-en-Y gastric bypass surgery (RYGB). Obese (24% body fat compared with 18% in chow-fed controls), male Sprague-Dawley rats maintained for 15 wk before and 4 mo after RYGB or sham-surgery on a two-choice low-fat/high-fat diet, were subjected to a series of tests assessing energy intake, meal patterning, and food choice. Although sham-operated rats gained an additional 100 g body wt during the postoperative period, RYGB rats lost ∼100 g. Intake of a nutritionally complete and palatable liquid diet (Ensure) was significantly reduced by ∼50% during the first 2 wk after RYGB compared with sham surgery. Decreased intake was the result of greatly reduced meal size with only partial compensation by meal frequency, and a corresponding increase in the satiety ratio. Similar results were obtained with solid food (regular or high-fat chow) 6 wk after surgery. In 12- to 24-h two-choice liquid or solid diet paradigms with nutritionally complete low- and high-fat diets, RYGB rats preferred the low-fat choice (solid) or showed decreased acceptance for the high-fat choice (liquid), whereas sham-operated rats preferred the high-fat choices. A separate group of rats offered chow only before surgery completely avoided the solid high-fat diet in a choice paradigm. The results confirm anecdotal reports of “nibbling” behavior and fat avoidance in RYGB patients and provide a basis for more mechanistic studies in this rat model.
Increased cerebral output of free radicals during hypoxia: implications for acute mountain sickness?
Authors: Bailey Damian M. , Taudorf Sarah , Berg Ronan M. G. , Lundby Carsten , McEneny Jane , Young Ian S. , Evans Kevin A. , James Philip E. , Shore Angharad , Hullin David A. , McCord Joe M. , Pedersen Bente K. , Möller Kirsten
Published: September 2009

This study examined whether hypoxia causes free radical-mediated disruption of the blood-brain barrier (BBB) and impaired cerebral oxidative metabolism and whether this has any bearing on neurological symptoms ascribed to acute mountain sickness (AMS). Ten men provided internal jugular vein and radial artery blood samples during normoxia and 9-h passive exposure to hypoxia (12.9% O2). Cerebral blood flow was determined by the Kety-Schmidt technique with net exchange calculated by the Fick principle. AMS and headache were determined with clinically validated questionnaires. Electron paramagnetic resonance spectroscopy and ozone-based chemiluminescence were employed for direct detection of spin-trapped free radicals and nitric oxide metabolites. Neuron-specific enolase (NSE), S100β, and 3-nitrotyrosine (3-NT) were determined by ELISA. Hypoxia increased the arterio-jugular venous concentration difference (a-vD) and net cerebral output of lipid-derived alkoxyl-alkyl free radicals and lipid hydroperoxides ( P < 0.05 vs. normoxia) that correlated with the increase in AMS/headache scores ( r = −0.50 to −0.90, P < 0.05). This was associated with a reduction in a-vDand hence net cerebral uptake of plasma nitrite and increased cerebral output of 3-NT ( P < 0.05 vs. normoxia) that also correlated against AMS/headache scores ( r = 0.74–0.87, P < 0.05). In contrast, hypoxia did not alter the cerebral exchange of S100β and both global cerebral oxidative metabolism (cerebral metabolic rate of oxygen) and neuronal integrity (NSE) were preserved ( P > 0.05 vs. normoxia). These findings indicate that hypoxia stimulates cerebral oxidative-nitrative stress, which has broader implications for other clinical models of human disease characterized by hypoxemia. This may prove a risk factor for AMS by a mechanism that appears independent of impaired BBB function and cerebral oxidative metabolism.
The instructive role of metanephric mesenchyme in ureteric bud patterning, sculpting, and maturation and its potential ability to buffer ureteric bud branching defects
Authors: Shah Mita M. , Tee James B. , Meyer Tobias , Meyer-Schwesinger Catherine , Choi Yohan , Sweeney Derina E. , Gallegos Thomas F. , Johkura Kohei , Rosines Eran , Kouznetsova Valentina , Rose David W. , Bush Kevin T. , Sakurai Hiroyuki , Nigam Sanjay K.
Published: September 2009

Kidney organogenesis depends on reciprocal interactions between the ureteric bud (UB) and the metanephric mesenchyme (MM) to form the UB-derived collecting system and MM-derived nephron. With the advent of in vitro systems, it is clear that UB branching can occur independently of MM contact; however, little has been done to detail the role of MM cellular contact in this process. Here, a model system in which the cultured isolated UB is recombined with uninduced MM is used to isolate the effects of the MM progenitor tissue on the development and maturation of the collecting system. By morphometrics, we demonstrate that cellular contact with the MM is required for vectorial elongation of stalks and tapering of luminal caliber of UB-derived tubules. Expression analysis of developmentally significant genes indicates the cocultured tissue is most similar to an embryonic day 19 ( E19) kidney. The likely major contributor to this is the functional maturation of the collecting duct and proximal nephron segments in the UB-induced MM, as measured by quantitative PCR, of the collecting duct-specific arginine vasopressin receptor and the nephron tubule segment-specific organic anion transporter OAT1, Na-Pitype 2 cotransporter, and Tamm-Horsfall protein gene expressions. However, expression of aquaporin-2 is upregulated similarly in isolated UB and cocultured tissue, suggesting that some aspects of functional maturation can occur independently of MM cellular contact. In addition to its sculpting effects, the MM normalized a “branchless” UB morphology induced by FGF7 or heregulin in isolated UB culture. The morphological changes induced by the MM were accompanied by a reassignment of GFRα1 (a receptor for GDNF) to tips. Such “quality control” by the MM of UB morphology may provide resiliency to the branching program. This may help to explain a number of knockout phenotypes in which branching and/or cystic defects are less impressive than expected. A second hit in the MM may thus be necessary to make these defects fully apparent.
Morg1 heterozygous mice are protected from acute renal ischemia-reperfusion injury
Authors: Hammerschmidt Elke , Loeffler Ivone , Wolf Gunter
Published: September 2009

Renal ischemia and reperfusion injury leads to acute renal failure when proinflammatory and apoptotic processes in the kidney are activated. The increase in hypoxia-inducible transcription factor-α (HIF-α), an important transcription factor for several genes, can attenuate ischemic renal injury. We recently identified a novel WD-repeat protein designated Morg1 (MAPK organizer 1) that interacts with prolyl hydroxylase 3 (PHD3), an important enzyme involved in the regulation of HIF-1α and HIF-2α expression. While homozygous Morg1 −/− mice are embryonic lethal, heterozygous Morg1 +/− mice have a normal phenotype. We show here that Morg1 +/− were partially protected from renal ischemia-reperfusion injury compared with wild-type Morg1 +/+ animals. Morg1 +/− mice compared with wild-type animals revealed a stronger increase in HIF-1α and HIF-2α expression in the ischemic-reperfused kidney associated with enhanced serum erythropoietin levels. However, no significant expression of HIF-1α and HIF-2α was found in nonischemic kidneys without any difference between Morg1 +/− and Morg1 +/+ mice. Ischemic kidneys of Morg1 +/− mice expressed more erythropoietin mRNA than ischemic kidneys from wild-type animals. Renal ischemia in Morg1 +/− mice resulted in a decrease in renal inflammation and reduction of proinflammatory cytokines (MCP-1, IP-10, MIP-2) compared with wild-type mice. Furthermore, there was significantly less apoptosis and tubular damage in Morg1 +/− kidneys after ischemia-reperfusion, and this was also reflected in significantly improved renal function compared with wild-type. Thus Morg1 may be a novel therapeutic target to limit renal injury after ischemia-reperfusion.
Early monitoring of acute tubular necrosis in the rat kidney by23Na-MRI
Authors: Atthe Bharath K. , Babsky Andriy M. , Hopewell Paige N. , Phillips Carrie L. , Molitoris Bruce A. , Bansal Navin
Published: September 2009

Reabsorption of water and other molecules is dependent on the corticomedullary sodium concentration gradient in the kidney. During the early course of acute tubular necrosis (ATN), this gradient is altered. Therefore,23Na magnetic resonance imaging (MRI) was used to study the alterations in renal sodium distribution in the rat kidney during ischemia and reperfusion (IR) injury, which induces ATN. In-magnet ischemia was induced for 0 (control), 10, 20, 30 or 50 min in Wistar rats.23Na images were collected every 10 min during baseline, ischemia, and 60-min reperfusion periods. T1and T2relaxation times were measured by both23Na-MRI and -MRS on a separate cohort of animals during ischemia and reperfusion for correction of relaxation-related tissue sodium concentration (TSC). A marked decrease was observed in the medulla and cortex23Na-MRI signal intensity (SI) during the early evolution of ATN caused by IR injury, with the sodium reabsorption function of the kidney being irreversibly damaged after 50 min of ischemia. Sodium relaxation time characteristics were similar in the medulla and cortex of normal kidney, but significantly decreased with IR. The changes in relaxation times in both compartments were identical; thus the medulla-to-cortex sodium SI ratio represents the TSC ratio of both compartments. The extent of IR damage observed with histological examination correlated with the23Na-MRI data.23Na-MRI has great potential for noninvasive, clinical diagnosis of evolving ATN in the setup of acute renal failure and in differentiating ATN from other causes of renal failure where tubular function is maintained.
Decreased renal perfusion rapidly increases plasma membrane Na-K-ATPase in rat cortex by an angiotensin II-dependent mechanism
Authors: Yingst Douglas R. , Araghi Ali , Doci Tabitha M. , Mattingly Raymond , Beierwaltes William H.
Published: September 2009

To understand how rapid changes in blood pressure can regulate Na-K-ATPase in the kidney cortex, we tested the hypothesis that a short-term (5 min) decrease in renal perfusion pressure will increase the amount of Na-K-ATPase in the plasma membranes by an angiotensin II-dependent mechanism. The abdominal aorta of anesthetized Sprague-Dawley rats was constricted with a ligature between the renal arteries, and pressure was monitored on either side during acute constriction. Left renal perfusion pressure was reduced to 70 ± 1 mmHg ( n = 6), whereas right renal perfusion pressure was 112 ± 4 mmHg. In control (nonconstricted) rats ( n = 5), pressure to both kidneys was similar at 119 ± 6 mmHg. After 5 min of reduced perfusion, femoral venous samples were taken for plasma renin activity (PRA) and the kidneys excised. The cortex was dissected, minced, sieved, and biotinylated. Lower perfusion left kidneys showed a 41% increase ( P < 0.003) in the amount of Na-K-ATPase in the plasma membrane compared with right kidneys. In controls, there was no difference in cell surface Na-K-ATPase between left and right kidneys ( P = 0.47 ). PRA was 57% higher in experimental animals compared with controls. To test the role of angiotensin II in mediating the increase in Na-K-ATPase, we repeated the experiments ( n = 6) in rats treated with ramiprilat. When angiotensin-converting enzyme was inhibited, the cell surface Na-K-ATPase of the two kidneys was equal ( P =0.46 ). These results confirm our hypothesis: rapid changes in blood pressure regulate trafficking of Na-K-ATPase in the kidney cortex.
AT1receptor-mediated uptake of angiotensin II and NHE-3 expression in proximal tubule cells through a microtubule-dependent endocytic pathway
Authors: Li Xiao C. , Hopfer Ulrich , Zhuo Jia L.
Published: September 2009

Angiotensin II (ANG II) is taken up by proximal tubule (PT) cells via AT1(AT1a) receptor-mediated endocytosis, but the underlying cellular mechanisms remain poorly understood. The present study tested the hypothesis that the microtubule- rather than the clathrin-dependent endocytic pathway regulates AT1-mediated uptake of ANG II and ANG II-induced sodium and hydrogen exchanger-3 (NHE-3) expression in PT cells. The expression of AT1receptors, clathrin light (LC) and heavy chain (HC) proteins, and type 1 microtubule-associated proteins (MAPs; MAP-1A and MAP-1B) in PT cells were knocked down by their respective small interfering (si) RNAs before AT1-mediated FITC-ANG II uptake and ANG II-induced NHE-3 expression were studied. AT1siRNAs inhibited AT1expression and blocked ANG II-induced NHE-3 expression in PT cells, as expected ( P < 0.01). Clathrin LC or HC siRNAs knocked down their respective proteins by ∼90% with a peak response at 24 h, and blocked the clathrin-dependent uptake of Alexa Fluor 594-transferrin ( P < 0.01). However, neither LC nor HC siRNAs inhibited AT1-mediated uptake of FITC-ANG II or affected ANG II-induced NHE-3 expression. MAP-1A or MAP-1B siRNAs markedly knocked down MAP-1A or MAP-1B proteins in a time-dependent manner with peak inhibitions at 48 h (>76.8%, P < 0.01). MAP protein knockdown resulted in ∼52% decreases in AT1-mediated FITC-ANG II uptake and ∼66% decreases in ANG II-induced NHE-3 expression ( P < 0.01). These effects were associated with threefold decreases in ANG II-induced MAP kinases ERK 1/2 activation ( P < 0.01), but not with altered AT1expression or clathrin-dependent transferrin uptake. Both losartan and AT1areceptor deletion in mouse PT cells completely abolished the effects of MAP-1A knockdown on ANG II-induced NHE-3 expression and activation of MAP kinases ERK1/2. Our findings suggest that the alternative microtubule-dependent endocytic pathway, rather than the canonical clathrin-dependent pathway, plays an important role in AT1(AT1a)-mediated uptake of extracellular ANG II and ANG II-induced NHE-3 expression in PT cells.
Context-Dependent Effects of NMDA Receptors on Precise Timing Information at the Endbulb of Held in the Cochlear Nucleus
Authors: Pliss Lioudmila , Yang Hua , Xu-Friedman Matthew A.
Published: September 2009

Many synapses contain both AMPA receptors (AMPAR) and N-methyl-d-aspartate receptors (NMDAR), but their different roles in synaptic computation are not clear. We address this issue at the auditory nerve fiber synapse (called the endbulb of Held), which is formed on bushy cells of the cochlear nucleus. The endbulb refines and relays precise temporal information to nuclei responsible for sound localization. The endbulb has a number of specializations that aid precise timing, including AMPAR-mediated excitatory postsynaptic currents (EPSCs) with fast kinetics. Voltage-clamp experiments in mouse brain slices revealed that slow NMDAR EPSCs are maintained at mature endbulbs, contributing a peak conductance of around 10% of the AMPAR-mediated EPSC. During repetitive synaptic activity, AMPAR EPSCs depressed and NMDAR EPSCs summated, thereby increasing the relative importance of NMDARs. This could impact temporal precision of bushy cells because of the slow kinetics of NMDARs. We tested this by blocking NMDARs and quantifying bushy cell spike timing in current clamp when single endbulbs were activated. These experiments showed that NMDARs contribute to an increased probability of firing, shorter latency, and reduced jitter. Dynamic-clamp experiments confirmed this effect and showed it was dose-dependent. Bushy cells can receive inputs from multiple endbulbs. When we applied multiple synaptic inputs in dynamic clamp, NMDARs had less impact on spike timing. NMDAR conductances much higher than mature levels could disrupt spiking, which may explain its downregulation during development. Thus mature NMDAR expression can support the conveying of precise temporal information at the endbulb, depending on the stimulus conditions.
Age-Related Declines in Visuospatial Working Memory Correlate With Deficits in Explicit Motor Sequence Learning
Authors: Bo J. , Borza V. , Seidler R. D.
Published: September 2009

Numerous studies have shown that older adults exhibit deficits in motor sequence learning, but the mechanisms underlying this effect remain unclear. Our recent work has shown that visuospatial working-memory capacity predicts the rate of motor sequence learning and the length of motor chunks formed during explicit sequence learning in young adults. In the current study, we evaluate whether age-related deficits in working memory explain the reduced rate of motor sequence learning in older adults. We found that older adults exhibited a correlation between visuospatial working-memory capacity and motor sequence chunk length, as we observed previously in young adults. In addition, older adults exhibited an overall reduction in both working-memory capacity and motor chunk length compared with that of young adults. However, individual variations in visuospatial working-memory capacity did not correlate with the rate of learning in older adults. These results indicate that working memory declines with age at least partially explain age-related differences in explicit motor sequence learning.
Asymmetric Changes in Cutaneous Reflexes After a Partial Spinal Lesion and Retention Following Spinalization During Locomotion in the Cat
Authors: Frigon Alain , Barrière Grégory , Leblond Hugues , Rossignol Serge
Published: September 2009

Locomotion involves dynamic interactions between the spinal cord, supraspinal signals, and peripheral sensory inputs. After incomplete spinal cord injury (SCI), interactions are disrupted, and remnant structures must optimize function to maximize locomotion. We investigated if cutaneous reflexes are altered following a unilateral partial spinal lesion and whether changes are retained within spinal circuits after complete spinal transection (i.e., spinalization). Four cats were chronically implanted with recording and stimulating electrodes. Cutaneous reflexes were evoked with cuff electrodes placed around left and right superficial peroneal nerves. Control data, consisting of hindlimb kinematics and electromyography (bursts of muscular activity and cutaneous reflexes), were recorded during treadmill locomotion. After stable control data were achieved (53–67 days), a partial spinal lesion was made at the 10th or 11th thoracic segment (T10–T11) on the left side. Cats were trained to walk after the partial lesion, and following a recovery period (64–80 days), a spinalization was made at T13. After the partial lesion, changes in short-latency excitatory (P1) homologous responses between hindlimbs, evoked during swing, were largely asymmetric in direction relative to control values, whereas changes in longer-latency excitatory (P2) and crossed responses were largely symmetric in direction. After spinalization, cats could display hindlimb locomotion within 1 day. Early after spinalization, reflex changes persisted a few days, but over time homologous P1 responses increased symmetrically toward or above control levels. Therefore changes in cutaneous reflexes after the partial lesion and retention following spinalization indicate an important spinal plasticity after incomplete SCI.
Loss of Responses to Visual But Not Electrical Stimulation in Ganglion Cells of Rats With Severe Photoreceptor Degeneration
Authors: Sekirnjak Chris , Hulse Clare , Jepson Lauren H. , Hottowy Pawel , Sher Alexander , Dabrowski Wladyslaw , Litke A. M. , Chichilnisky E. J.
Published: September 2009

Retinal implants are intended to help patients with degenerative conditions by electrically stimulating surviving cells to produce artificial vision. However, little is known about how individual retinal ganglion cells respond to direct electrical stimulation in degenerating retina. Here we used a transgenic rat model to characterize ganglion cell responses to light and electrical stimulation during photoreceptor degeneration. Retinas from pigmented P23H-1 rats were compared with wild-type retinas between ages P37 and P752. During degeneration, retinal thickness declined by 50%, largely as a consequence of photoreceptor loss. Spontaneous electrical activity in retinal ganglion cells initially increased two- to threefold, but returned to nearly normal levels around P600. A profound decrease in the number of light-responsive ganglion cells was observed during degeneration, culminating in retinas without detectable light responses by P550. Ganglion cells from transgenic and wild-type animals were targeted for focal electrical stimulation using multielectrode arrays with electrode diameters of ∼10 microns. Ganglion cells were stimulated directly and the success rate of stimulation in both groups was 60–70% at all ages. Surprisingly, thresholds (∼0.05 mC/cm2) and latencies (∼0.25 ms) in P23H rat ganglion cells were comparable to those in wild-type ganglion cells at all ages and showed no change over time. Thus ganglion cells in P23H rats respond normally to direct electrical stimulation despite severe photoreceptor degeneration and complete loss of light responses. These findings suggest that high-resolution epiretinal prosthetic devices may be effective in treating vision loss resulting from photoreceptor degeneration.
Inhibition of Glutathione and Thioredoxin Metabolism Enhances Sensitivity to Perifosine in Head and Neck Cancer Cells
Authors: Simons Andrean L. , Parsons Arlene D. , Foster Katherine A. , Orcutt Kevin P. , Fath Melissa A. , Spitz Douglas R.
Published: September 2009

The hypothesis that the Akt inhibitor, perifosine (PER), combined with inhibitors of glutathione (GSH) and thioredoxin (Trx) metabolism will induce cytotoxicity via metabolic oxidative stress in human head and neck cancer (HNSCC) cells was tested. PER induced increases in glutathione disulfide (%GSSG) in FaDu, Cal-27, and SCC-25 HNSCCs as well as causing significant clonogenic cell killing in FaDu and Cal-27, which was suppressed by simultaneous treatment with N-acetylcysteine (NAC). An inhibitor of GSH synthesis, buthionine sulfoximine (BSO), sensitized Cal-27 and SCC-25 cells to PER-induced clonogenic killing as well as decreased total GSH and increased %GSSG. Additionally, inhibition of thioredoxin reductase activity (TrxRed) with auranofin (AUR) was able to induce PER sensitization in SCC-25 cells that were initially refractory to PER. These results support the conclusion that PER induces oxidative stress and clonogenic killing in HNSCC cells that is enhanced with inhibitors of GSH and Trx metabolism.
The Incidence and Management of Pleural Injuries Occurring during Open Nephrectomy
Authors: Atmaca Ali Fuat , Canda Abdullah Erdem , Serefoglu Ege Can , Altinova Serkan , Ozdemir Ahmet Tunc , Balbay M. Derya
Published: September 2009

Objective. To evaluate the incidence, management, and risk factors of pleural injuries occurring during open nephrectomy.Methods. Between June 2004/and June 2008, 165 patients (167 renal units) underwent open simple (n=37,22.2%), partial (n=39,23.4%) or radical (n=91,54.5%) nephrectomy in our institution.Results. Flank, Chevron, and abdominal midline incisions were used in 148(88.6%), 17(10.2%), and in 2(1.2%) surgical procedures, respectively. Ribs were excised in 109(65.3%) procedures (11th rib, 10th-11th ribs, and 11th-12th ribs). Intraoperative pleural injuries were detected in 20(12%) procedures, 16(80%) were treated successfully with simple evacuation technique, and 4 required chest tube insertion. Age, sex, surgery type, incision type, and surgery site were not associated with pleural injury occurrence (P>.05). Rib resection was the only parameter associated with pleural injury occurrence.Conclusion. Pleural injuries occur in 12% of open nephrectomy procedures, and 80% can be repaired successfully. Few of them (2.4%) need chest tube insertion. Performing rib resection is a significant risk factor for pleural injury occurrence during nephrectomies.
Virtual Screening as a Technique for PPAR Modulator Discovery
Authors: Lewis Stephanie N. , Bassaganya-Riera Josep , Bevan David R.
Published: September 2009

Virtual screening (VS) is a discovery technique to identify novel compounds with therapeutic and preventive efficacy against disease. Our current focus is on the in silico screening and discovery of novel peroxisome proliferator-activated receptor-gamma (PPARγ) agonists. It is well recognized that PPARγagonists have therapeutic applications as insulin sensitizers in type 2 diabetes or as anti-inflammatories. VS is a cost- and time-effective means for identifying small molecules that have therapeutic potential. Our long-term goal is to devise computational approaches for testing the PPARγ-binding activity of extensive naturally occurring compound libraries prior to testing agonist activity using ligand-binding and reporter assays. This review summarizes the high potential for obtaining further fundamental understanding of PPARγbiology and development of novel therapies for treating chronic inflammatory diseases through evolution and implementation of computational screening processes for immunotherapeutics in conjunction with experimental methods for calibration and validation of results.
Cardiovascular risk factors in idiopathic compared to riskassociated venous thromboembolism: A focus on fibrinogen, factor VIII, and high-sensitivity C-reactive protein (hs-CRP)
Authors: Schmitt Joern , Humpich Marek , Glowatzki Matthias , Dressler Dejan , Seifried Erhard , Lindhoff-Last Edelgard , Luxembourg Beate
Published: September 2009

There have recently been reports of an increased incidence of arterial cardiovascular events in patients with idiopathic venous thromboembolism (VTE) compared to patients with risk-associated VTE. The aim of our study was to evaluate whether elevated clotting factors, which have been linked to chronic subclinical inflammation and arterial thromboembolic disease, have a higher prevalence in idiopathic VTE compared to secondary VTE.Plasma fibrinogen,factor VIII,and high-sensitivity C-reactive protein (hs-CRP) levels were determined in a cohort of sex and age-matched patients with unprovoked VTE (n=101), patients with secondary VTE (n=101), and controls (n=202). Fibrinogen and hs-CRP levels were higher in patients with idiopathic VTE (fibrinogen: median/range: 331/214-524 mg/dl; hs-CRP: median/interquartile range: 1.8/0.8-3.7 mg/l) than in those with risk-associated VTE (299/162-458 mg/dl, p=0.004; 1.5/0.8-2.2 mg/l, p=0.05) and controls (302/185-644 mg/dl, p=0.001; 1.2/0.5-2.2
The A6936G polymorphism of the endothelial protein C receptor gene is associated with the risk of unexplained foetal loss in Mediterranean European couples
Authors: Fabbro-Peray Pascale , Marès Pierre , Mismetti Patrick , Lissalde-Lavigne Géraldine , Cochery-Nouvellon Éva , Chauleur Céline , Demattei Christophe , Mercier Éric , Gris Jean-Christophe
Published: September 2009

The endothelial protein C receptor (EPCR) is expressed by trophoblast cells. Mid-gestation pregnancy loss is described in animals with a haemochorial placenta lacking EPCR. The A6936G allele of the EPCR gene (PROCR) may be associated with lower EPCR densities on trophoblasts, but data are lacking for its effect on the risk of pregnancy loss in humans. A 1:2 case-control study on unexplained pregnancy loss was nested in the NOHA First cohort: 3,218 case couples and 6,436 control couples were studied for PROCR A6936G, coagulation factor V gene (F5) G1691A and coagulation factor II gene (F2) G20210A polymorphisms. Ethnicity and time of pregnancy loss defined through biometry-based gestational ages (embryonic loss < 10th week ≥ foetal loss) were analysed. The PROCR A6936G allele, in mothers and fathers, was associated only with foetal loss in both Europeans and non-Europeans. Increasing probability levels of carrying a homozygous child were increasingly associated with the risk of foetal demise. The F5 G1691A and F2 G20210A alleles, only in mothers, were only and independently associated with foetal loss in Europeans. In our population, the PROCR A6936G allele describes women, but also men and thus couples, at risk for first unexplained foetal loss. This risk is independent of the foetal loss risk conferred to our local Mediterranean European women by the F5 G1691A and F2 G20210A alleles. Data confirm that the relationship between thrombophilias and pregnancy loss varies according to ethnicity and loss type.
The tumour necrosis factor superfamily ligand APRIL (TNFSF13) is released upon platelet activation and expressed in atherosclerosis
Authors: Sandberg Wiggo J. , Otterdal Kari , Gullestad Lars , Halvorsen Bente , Ragnarsson Asgrimur , Frøland Stig S. , Damås Jan K. , Øie Erik , Hansson Göran K. , Yndestad Arne , Aukrust Pål
Published: September 2009

Activated platelets release a wide range of inflammatory mediators, including members of the tumour necrosis factor (TNF) superfamily (e.g. CD40 ligand [CD40L] and LIGHT). Such platelet-mediated inflammation could be involved in atherogenesis and plaque destabilisation. In the present study we investigated whether APRIL, another member of the TNF superfamily that has been detected in megakaryocytes, could be released from platelets upon activation. The release of APRIL was studied in thrombin receptor (SFLLRN) activated platelets, and the expression of APRIL was examined in plasma and within the atherosclerotic lesion in patients with carotid and coronary atherosclerosis. Upon SFLLRN activation, there was a gradual release of APRIL, reaching maximum after 90 minutes. While this pattern is similar to that of CD40L and LIGHT, the release of APRIL was quite differently regulated. Thus, prostaglandin E1,but not inhibitors of metal-dependent proteases and actin polymerisation or the lack of GP IIb/IIIa, blocks APRIL release in activated platelets. With relevance to atherogenesis, we found that patients with coronary artery disease (n=80) had raised plasma levels of APRIL as compared with controls (n=20), and APRIL immunoreactivity was detected in aggregated platelets within the ruptured plaque in patients with myocardial infarction and within macrophages in symptomatic carotid plaques. In conclusion, activated platelets release significant amounts of APRIL in a longlasting manner, differently regulated than the gradual release of other platelet-derived TNF superfamily ligands. The enhanced expression of APRIL in atherosclerotic disorders, both systemically and within the lesion, may suggest a potential involvement of APRIL in atherogenesis.
Proliferative stimulation of the vascular endothelin-1 axis in vitro and ex vivo by infection with Chlamydia pneumoniae
Authors: Kern Jan , Maass Viola , Rupp Jan , Maass Matthias
Published: September 2009

Endothelin-1 (ET-1) is a vasoactive peptide that modifies vascular function via the G-protein coupled transmembrane receptors, Endothelin-A receptor (ETAR) and Endothelin-B receptor (ETBR). Dysregulation of the ET-1 axis plays a role in atherosclerotic development as it triggers cell proliferation, inflammation, and vasoconstriction.The respiratory pathogen Chlamydia pneumoniae (Cp) has been recovered from atherosclerotic lesions, and related to atherogenesis, via activation of vascular small GTPases and leukocyte recruitment. Cp effectively reprograms host cell signalling and is able to enter an intracellular persistent state in vascular cells that is refractory to antibiotics. Upon chlamydial infection, vascular smooth muscle cells, which do not produce significant ET-1 under physiological conditions were switched into a fundamental source of ET-1 mRNA and protein in a p38-MAP-kinase-dependent pathway. Endothelial cells did not overproduce ET-1 but showed upregulation of mitogenic ETAR mRNA and protein while the counterbalancing ETBR, which regulates ET-1 clearance, remained unaffected.This disruption of the ET-1 axis was confirmed in an ex vivo mouse aortic ring model, and resulted in endothelial cell proliferation that could be abrogated by ETAR-siRNA and the selective ETAR-antagonist BQ-123. Chronic chlamydial infection of the vascular wall might represent a permanent noxious stimulus linked to the endothelial cell proliferation characteristic of early atherosclerosis. Suppression of this deleterious paracrine loop by ETAR antagonism opens up a new option of preventing possible vascular sequelae of otherwise untreatable chronic chlamydial infection. In conclusion, this is the first study to demonstrate infection to dysregulate the ET-1 axis towards inducing a proatherogenic proliferative phenotype.
Is perioperative point-of-care prothrombin time testing accurate compared to the standard laboratory test?
Authors: Urwyler Natalie , Staub Lukas P. , Beran Dominik , Deplazes Marcus , Lord Sarah J. , Alberio Lorenzo , Greif Robert , Theiler Lorenz
Published: September 2009

There is no accepted way of measuring prothrombin time without time loss for patients undergoing major surgery who are at risk of intraoperative dilution and consumption coagulopathy due to bleeding and volume replacement with crystalloids or colloids. Decisions to transfuse fresh frozen plasma and procoagulatory drugs have to rely on clinical judgment in these situations. Point-of-care devices are considerably faster than the standard laboratory methods. In this study we assessed the accuracy of a Point-of-care (PoC) device measuring prothrombin time compared to the standard laboratory method. Patients undergoing major surgery and intensive care unit patients were included. PoC prothrombin time was measured by CoaguChek® XS Plus (Roche Diagnostics, Switzerland). PoC and reference tests were performed independently and interpreted under blinded conditions. Using a cut-off prothrombin time of 50%, we calculated diagnostic accuracy measures, plotted a receiver operating characteristic (ROC) curve and tested for equivalence between the two methods. PoC sensitivity and specificity were 95% (95% CI 77%, 100%) and 95% (95% CI 91%, 98%) respectively. The negative likelihood ratio was 0.05 (95% CI 0.01, 0.32). The positive likelihood ratio was 19.57 (95% CI 10.62, 36.06). The area under the ROC curve was 0.988. Equivalence between the two methods was confirmed. CoaguChek® XS Plus is a rapid and highly accurate test compared with the reference test. These findings suggest that PoC testing will be useful for monitoring intraoperative prothrombin time when coagulopathy is suspected. It could lead to a more rational use of expensive and limited blood bank resources.
Real-life anticoagulation treatment of atrial fibrillation after catheter ablation: Possible overtreatment of low-risk patients
Authors: Hindricks Gerhard , Kottkamp Hans , Sommer Philipp , Gaspar Thomas , Bode Kerstin , Arya Arash , Rallidis Loukianos S. , Kremastinos Dimitrios Th. , Piorkowski Christopher , Dagres Nikolaos
Published: September 2009

Catheter ablation provides curative treatment for atrial fibrillation (AF). Data on anticoagulation after the procedure are sparse. We investigated real-life antithrombotic treatment after AF ablation and examined its adherence to current recommendations. Eight hundred forty-four patients (age 58 ±10 years) underwent AF ablation. Most patients had a CHADS2 score of 0 (46%) or 1 (45%). Seven-day Holter was performed at three, six and 12 months after ablation. Decision on anticoagulation treatment was made by general practitioners and referring cardiologists in consultation with the patients. At discharge, anticoagulants were prescribed for the vast majority (94–96%) of patients. This percentage remained high at three and six months (80–90%) without differences between stroke risk groups. At 12 months, the use of anticoagulants was mainly influenced by the detection of recurrence; usage exceeded 90% in all stroke risk groups in patients with recurrences. In patients without recurrences, differences between risk groups were significant but small, ranging from 42% (CHADS2=0) to 62% (CHADS2≥2) (p=0.033). In multivariate analysis, the only factor independently associated with oral anticoagulation at 12 months was the detection of recurrences (odds ratio=16.2, p<0.001), whereas the effect of the CHADS2 score was not significant (p=0.080).The effect of all other examined factors was also not significant. Contrary to current recommendations, anticoagulation after AF ablation is hardly guided by the stroke risk profile and remains high even in low-risk patients. The most important factor influencing the use of anticoagulants is the detection of recurrences during follow-up. This results in possible overtreatment of low-risk patients.
Genetic fusion to albumin improves the pharmacokinetic properties of factor IX
Authors: Weimer Thomas , Kronthaler Ulrich , Lang Wiegand , Schulte Stefan , Metzner Hubert J.
Published: September 2009

Haemophilia B is a X-chromosome linked disease characterised by a deficiency of functionally active coagulation Factor IX (FIX). Patients with severe haemophilia B at risk of recurrent bleeding are treated approximately twice a week in a prophylactic setting by application of FIX concentrates.To increase convenience and compliance of the therapy it is desirable to reduce the dosing frequency by improving the pharmacokinetic properties of FIX. Here a concept of rFIX (recombinant factor IX) albumin fusion proteins (rIX-FPs) with cleavable linker peptides derived from the FIX activation sequence is presented. Constructs of the genetic fusion of FIX to albumin via cleavable linkers were expressed in mammalian cells and characterised after purification. In vitro activation studies with FXIa demonstrated that cleavage of the linker and the activation peptide proceeded comparably well. In a clotting assay the rIX-FPs with cleavable linker showed a 10- to 30-fold increase in the molar specific clotting activity compared to fusion proteins with non-cleavable linkers. Furthermore, in-vivo recovery, terminal half-life and the AUC of rIX-FPs in rats and rabbits as determined by FIX antigen measurements were significantly increased compared to rFIX (BeneFIX®). In FIX deficient (FIX−/−) mice the in-vivo recovery and the AUC were also significantly increased.The efficacy in reducing bleeding time was shown in FIX−/−mice by a tail tip bleeding model. The results suggest that rIX-FPs with a cleavable linker between FIX and albumin are a promising concept that may support the use of the albumin fusion technology to extend the half-life of FIX.
Association of fatigue and psychological distress with quality of life in patients with a previous venous thromboembolic event
Authors: Lukas Paul , Krummenacher René , Biasiutti Franziska , Begré Stefan , Znoj Hansjörg , von Känel Roland
Published: September 2009

Health-related quality of life (QoL) has been associated with several social and medical conditions in patients with deep vein thrombosis (DVT) and pulmonary embolism (PE).To the best of our knowledge,there is no study investigating the relationship of QoL with psychological variables in this patient population.We assumed as a hypothesis an association between heightened levels of fatigue and psychological distress, as well as decreased QoL in patients with an objectively diagnosed venous thromboembolic event. Study participants were 205 consecutively enrolled out-patients (47.4 years, 54.6% men) with DVT and/or PE. Approximately 10 days before blood collection for thrombophilia work-up, QoL, fatigue, and psychological distress were assessed using the Short Form Health Survey (SF-12), the Multidimensional Fatigue Symptom Inventory Short Form (MFSI-SF) as well as the Hospitality Anxiety and Depression scale (HADS). After controlling for demographic and medical factors, fatigue (p<0.01) but not psychological distress (p>0.05) was negatively associated with physical QoL, explaining 11.0% of the variance. Fatigue (p<0.001) and psychological distress (p<0.001) were significant predictors of mental QoL,explaining an additional 36.2% and 3.6% of the variance. Further analyses revealed that all subscales of the HADS (e.g. anxiety and depression) and of the MFSI-SF (e.g. general fatigue, physical fatigue, emotional fatigue, mental fatigue and vigor) were significant predictors of mental QoL. MFSI-SF subscales also predicted physical QoL. The findings suggest that fatigue and psychological distress substantially predict QoL in patients with a previous venous thromboembolic event above and beyond demographic factors.
Risk factors for cerebral venous thrombosis and deep venous thrombosis in patients aged between 15 and 50 years
Authors: Uyttenboogaart Maarten , Vroomen Patrick C. A. J. , De Keyser Jacques , Luijckx Gert-Jan , Koopman Karen , van der Meer Jan
Published: September 2009

Cerebral venous thrombosis (CVT) and deep vein thrombosis or pulmonary embolism (DVT/PE) are associated with many risk factors. It is unclear why CVT occurs less often than DVT/PE. Age dependent risk factors may play a role. The aim of our study was to compare risk factors in a uniform age group of CVT and DVT/PE patients aged between 15 and 50 years. Thrombophilic markers and clinical risk factors of 79 CVT patients and 173 DVT/PE patients aged 15–50 years were compared. Multivariable logistic regression analysis was performed to investigate if risk factors were independently associated with CVT or DVT/ PE. Cerebral venous thrombosis patients were younger (median age 30 years vs. 42 years; p<0.001) and more often female (82% vs. 52%; p<0.001). There were no differences in thrombophilic markers. Cerebral venous thrombosis was less often associated with trauma, immobilisation or surgery than DVT/PE (6% vs. 21%; adjusted OR 0.29; 95%CI 0.10–0.82). In women, CVT was more frequently associated with oral contraceptive use, pregnancy or puerperium (82% vs. 53%; adjusted OR 2.34; 95%CI 1.03–5.32).This study demonstrated no differences in thrombophilic markers between CVT patients and DVT/PE patients aged between 15 and 50 years, while the frequency of some transient risk factors was different. Cerebral venous thrombosis was relatively more common in women and hormonal factors may predispose to CVT compared to DVT/PE, while trauma, immobilisation and surgery may be less important in the pathophysiology of CVT.
The Humdrum Use of Ultimate Authority: Defining and Analysing Chapter VII Resolutions
Authors: Johansson Patrik
Published: September 2009

Under Chapter VII of the Charter of the United Nations, the Security Council has the unique authority to make decisions that are binding on member states. However, the lack of a standard definition of what makes a Security Council resolution "a Chapter VII resolution" has caused disagreement regarding the status of several resolutions. This is unfortunate as the international community should never have to doubt whether a Security Council resolution is in fact adopted under Chapter VII or not. It is also unnecessary. This article addresses this problem by proposing a definition of Chapter VII resolutions, based on two criteria referred to as "Article 39 determinations" and "Chapter VII decisions". On the basis of the proposed definition, the article describes and analyses a dramatic increase in the use of Chapter VII during the post-Cold War era. It concludes that as Chapter VII has come to constitute the majority of Security Council resolutions in recent years, the resort to Chapter VII no longer signifies exceptional determination and resolve, which it did during the Cold War; instead Chapter VII today implies business as usual. An appendix lists all Chapter VII resolutions from 1946–2008.
The Contribution of the International Court of Justice to the Law on the Use of Force: Missed Opportunities or Unrealistic Expectations?
Authors: McKeever David
Published: September 2009

In recent years, the International Court of Justice has been presented with opportunities to pronounce on important dimensions of the law on the use of force. An assessment of the court's handling of these issues must consider first the role attributed to the Court within the international legal regime for preventing and mitigating the use of force, and thus what exactly would amount to 'success' for the Court in such cases. Notwithstanding the inherent limitations on the Court's capacity in this area, this article argues that the Court has largely failed to provide clear guidance on pressing legal questions. An unwarranted caution in utilising the judicial tools at its disposal is one important factor in this regard. Finally, this article highlights some potential consequences of the Court's recent work for the development of international law on the use of force.
Measuring the Maturity of Developing Cotton Fibers using an Automated Polarized Light Microscopy Technique
Authors: Long Robert L. , Bange Michael P. , Gordon Stuart G. , Constable Greg A.
Published: September 2009

Cotton fibers are trichome cells composed primarily of cellulose. Mature fibers have more cellulose and a greater degree of cell wall thickening, and perform better than less mature fibers during textile processing. An automated polarized light microscope instrument called Siro-Mat that measures cotton fiber cell wall thickening was employed to assess the maturity of developing fibers from single cotton fruit. Fruit were taken from the first fruiting branch and position on glasshouse grown Gossypium hirsutum L. (Upland) and G. barbadense L. (Pima) plants, sequentially harvested from 24 days postanthesis (dpa) at approximately four-day intervals up until approximately 50 dpa. The instrument assessed an average of 13,000 fiber snippets per fruit. Upland fibers matured at a slower rate than Pima fibers up to 35 dpa. However, after 45 dpa Upland fibers had achieved a higher average maturity (i.e. 0.99 birefringence maturity index (BMI), cf. 0.79 for Pima). For both species the uniformity of fiber maturity increased as fibers matured up until 35 dpa for Upland and 29 dpa for Pima (i.e. the BMI coefficient of variation decreased as BMI increased during fruit development). It is envisaged that SiroMat will be a useful tool in helping to understand and manage fiber maturity by characterizing the maturation dynamics of cultivars with different inherent fiber properties, and for cultivars subjected to different environmental and agronomic conditions.
Predictors of Black Students’ Race-Related Reasons for Choosing an HBCU and Intentions to Engage in Racial Identity—Relevant Behaviors
Authors: Van Camp Debbie , Barden Jamie , Sloan Lloyd R.
Published: September 2009

This study explores the antecedents and consequences of race-related reasons for historically Black college and university (HBCU) choice. A total of 109 undergraduate students attending a historically Black university completed questionnaires assessing their race-related reasons for choosing the university and their intention to engage in race-related activities, as well as individual difference measures. Students with less contact with other Blacks growing up or more central racial identities were more likely to cite race-related reasons for HBCU college choice. Furthermore, lack of contact and higher racial centrality predicted greater intention to engage in behaviors to develop racial identity (e.g., race-oriented clubs and personal reading). Critically, race-related reasons for college choice mediated the impact of both contact and centrality on behavioral intentions. Finally, non-race-related reasons for college choice (i.e., academic and financial) were distinct from race-related reasons and failed to predict race-relevant behavioral intentions. Thus, the race-related reasons behind this critical life choice form a bridge between the race-relevant aspects of the past and intentions to engage in racial identity— developing behaviors in the future.