bluuebunny/crossref_metadata_2025 huggingface dataset:
In Situ Analysis of Sulfur Species in Sulfur Globules Produced from Thiosulfate by
Thermoanaerobacter sulfurigignens
and
Thermoanaerobacterium thermosulfurigenes
Authors: Lee Yong-Jin , Prange Alexander , Lichtenberg Henning , Rohde Manfred , Dashti Mona , Wiegel Juergen
Published: July 2007

The
Firmicutes Thermoanaerobacter sulfurigignens
and
Thermoanaerobacterium thermosulfurigenes
convert thiosulfate, forming sulfur globules inside and outside cells. X-ray absorption near-edge structure analysis revealed that the sulfur consisted mainly of sulfur chains with organic end groups similar to sulfur formed in purple sulfur bacteria, suggesting the possibility that the process of sulfur globule formation by bacteria is an ancient feature.
A Novel Indole Compound That Inhibits
Pseudomonas aeruginosa
Growth by Targeting MreB Is a Substrate for MexAB-OprM
Authors: Robertson Gregory T. , Doyle Timothy B. , Du Qun , Duncan Leonard , Mdluli Khisimuzi E. , Lynch A. Simon
Published: July 2007

Drug efflux systems contribute to the intrinsic resistance of
Pseudomonas aeruginosa
to many antibiotics and biocides and hamper research focused on the discovery and development of new antimicrobial agents targeted against this important opportunistic pathogen. Using a
P. aeruginosa
PAO1 derivative bearing deletions of
opmH
, encoding an outer membrane channel for efflux substrates, and four efflux pumps belonging to the resistance nodulation/cell division class including
mexAB-oprM
, we identified a small-molecule indole-class compound (CBR-4830) that is inhibitory to growth of this efflux-compromised strain. Genetic studies established MexAB-OprM as the principal pump for CBR-4830 and revealed MreB, a prokaryotic actin homolog, as the proximal cellular target of CBR-4830. Additional studies establish MreB as an essential protein in
P. aeruginosa
, and efflux-compromised strains treated with CBR-4830 transition to coccoid shape, consistent with MreB inhibition or depletion. Resistance genetics further suggest that CBR-4830 interacts with the putative ATP-binding pocket in MreB and demonstrate significant cross-resistance with A22, a structurally unrelated compound that has been shown to promote rapid dispersion of MreB filaments in vivo. Interestingly, however, ATP-dependent polymerization of purified recombinant
P. aeruginosa
MreB is blocked in vitro in a dose-dependent manner by CBR-4830 but not by A22. Neither compound exhibits significant inhibitory activity against mutant forms of MreB protein that bear mutations identified in CBR-4830-resistant strains. Finally, employing the strains and reagents prepared and characterized during the course of these studies, we have begun to investigate the ability of analogues of CBR-4830 to inhibit the growth of both efflux-proficient and efflux-compromised
P. aeruginosa
through specific inhibition of MreB function.
The Unusual 23S rRNA Gene of
Coxiella burnetii
: Two Self-Splicing Group I Introns Flank a 34-Base-Pair Exon, and One Element Lacks the Canonical ΩG
Authors: Raghavan Rahul , Miller Scott R. , Hicks Linda D. , Minnick Michael F.
Published: July 2007

We describe the presence and characteristics of two self-splicing group I introns in the sole 23S rRNA gene of
Coxiella burnetii
. The two group I introns, Cbu.L1917 and Cbu.L1951, are inserted at sites 1917 and 1951 (
Escherichia coli
numbering), respectively, in the 23S rRNA gene of
C. burnetii
. Both introns were found to be self-splicing in vivo and in vitro even though the terminal nucleotide of Cbu.L1917 is adenine and not the canonical conserved guanine, termed ΩG, found in Cbu.L1951 and all other group I introns described to date. Predicted secondary structures for both introns were constructed and revealed that Cbu.L1917 and Cbu.L1951 were group IB2 and group IA3 introns, respectively. We analyzed strains belonging to eight genomic groups of
C. burnetii
to determine sequence variation and the presence or absence of the elements and found both introns to be highly conserved (≥99%) among them. Although phylogenetic analysis did not identify the specific identities of donors, it indicates that the introns were likely acquired independently; Cbu.L1917 was acquired from other bacteria like
Thermotoga subterranea
and Cbu.L1951 from lower eukaryotes like
Acanthamoeba castellanii
. We also confirmed the fragmented nature of mature 23S rRNA in
C. burnetii
due to the presence of an intervening sequence. The presence of three selfish elements in
C. burnetii
's 23S rRNA gene is very unusual for an obligate intracellular bacterium and suggests a recent shift to its current lifestyle from a previous niche with greater opportunities for lateral gene transfer.
Characterization of the
Erwinia chrysanthemi gan
Locus, Involved in Galactan Catabolism
Authors: Delangle Aurélie , Prouvost Anne-France , Cogez Virginie , Bohin Jean-Pierre , Lacroix Jean-Marie , Cotte-Pattat Nicole Hugouvieux
Published: July 2007

β-1,4-Galactan is a major component of the ramified regions of pectin. Analysis of the genome of the plant pathogenic bacteria
Erwinia chrysanthemi
revealed the presence of a cluster of eight genes encoding proteins potentially involved in galactan utilization. The predicted transport system would comprise a specific porin GanL and an ABC transporter made of four proteins, GanFGK
2
. Degradation of galactans would be catalyzed by the periplasmic 1,4-β-endogalactanase GanA, which released oligogalactans from trimer to hexamer. After their transport through the inner membrane, oligogalactans would be degraded into galactose by the cytoplasmic 1,4-β-exogalactanase GanB. Mutants affected for the porin or endogalactanase were unable to grow on galactans, but they grew on galactose and on a mixture of galactotriose, galactotetraose, galactopentaose, and galactohexaose. Mutants affected for the periplasmic galactan binding protein, the transporter ATPase, or the exogalactanase were only able to grow on galactose. Thus, the phenotypes of these mutants confirmed the functionality of the
gan
locus in transport and catabolism of galactans. These mutations did not affect the virulence of
E. chrysanthemi
on chicory leaves, potato tubers, or
Saintpaulia ionantha
, suggesting an accessory role of galactan utilization in the bacterial pathogeny.
Flavobacterium johnsoniae
SprA Is a Cell Surface Protein Involved in Gliding Motility
Authors: Nelson Shawn S. , Glocka Padden P. , Agarwal Sarika , Grimm David P. , McBride Mark J.
Published: July 2007

Flavobacterium johnsoniae
cells glide rapidly over surfaces by an unknown mechanism. Transposon-induced
sprA
mutants formed nonspreading colonies on agar, and the cells examined in wet mounts were deficient in attachment to surfaces and were almost completely nonmotile. Exposure of intact cells to proteinase K cleaved the 270-kDa SprA into several large peptides, suggesting that it is partially exposed on the cell surface.
Injuries in female football players in top-level international tournaments
Authors: Junge Astrid , Dvorak Jiri
Published: July 2007

Background:Despite the growing popularity of women’s football and the increasing number of female players, there has been little research on injuries sustained by female football players.

Purpose:Analysis of the incidence, characteristics and circumstances of injury in elite female football players in top-level international tournaments.

Study design:Prospective survey.

Methods:Injuries incurred in seven international football tournaments were analysed using an established injury report system. Doctors of all participating teams reported all injuries after each match on a standardised injury reporting form. The mean response rate was 95%.

Results:387 injuries were reported from 174 matches, equivalent to an incidence of 67.4 injuries/1000 player hours (95% CI 60.7 to 74.1) or 2.2 injuries/match (95% CI 2.0 to 2.4). Most injuries (84%; 317/378) were caused by contact with another player. The injuries most commonly involved the lower extremity (n = 248; 65%), followed by injuries of the head and neck (n = 67, 18%), trunk (n = 33, 9%) and upper extremity (n = 32, 8%). Contusions (n = 166; 45%) were the most frequent type of injury, followed by sprains or ligament rupture (n = 96; 26%) and strains or muscle fibre ruptures (n = 31; 8%). The most common diagnosis was an ankle sprain. There were 7 ligament ruptures and 15 sprains of the knee. On average 1 injury/match (95% CI 0.8 to 1.2) was expected to result in absence from a match or training.

Conclusion:The injury rate in women’s top-level tournaments was within the range reported previously for match injuries in elite male and female players. However, the diagnoses and mechanisms of injury among the female players differed substantially from those previously reported in male football players.
SQUEEZING EFFECTS IN THE SUM AND DIFFERENCE OF THE FIELD AMPLITUDE IN THE RAMAN PROCESS
Authors: SEN BISWAJIT , MANDAL SWAPAN
Published: July 2007

Under the short-time approximation, Giri and Gupta1 investigated the sum and difference squeezing of the field amplitude in the Raman process. The relations between the normal squeezing and the sum and difference squeezing of the field amplitude are explicitly exhibited. They argued that the sum and difference squeezing of the field amplitude are essentially the squeezing in higher-order sense. Upon verification of the results of Giri and Gupta, we observe that the entire calculations and the conclusions thereof are misleading and baseless. To substantiate our claim, we give the correct expressions for the useful variances. Interestingly, there is no possibility of getting normal squeezing, sum squeezing and difference squeezing of the input state prepared in coherent state.
THEORETICAL STUDIES ON LINEAR AND NONLINEAR OPTICAL CHARACTERIZATION AND OPTICAL LIMITING PROPERTY OF Pb(II), In(III) CHLORIDE, Ni(II) METALLATED 1,4,8,11,15,18,22,25-OCTAALKYLPHTHALOCYANINES
Authors: KARAKAS ASLI , ELMALI AYHAN
Published: July 2007

To provide an insight into the optical limiting (OL) behavior of a series of 3 metallated 1,4,8,11,15,18,22,25-octaalkylphthalocyanines; the third-order nonlinear optical (NLO) properties, one-photon absorption (OPA) and two-photon absorption (TPA) characterizations have been theoretically investigated by means of AM1, ZINDO and configuration interaction (CI) methods. The highest values for the TPA cross-section (δ(ω)) are exhibited by derivatives metallated with indium and lead. It is also seen that the nickel-metallated compound might be a passive optical limiter of the series, indicating the weakest δ(ω) and second hyperpolarizability (γ). Our calculated results are in good agreement with the previous experimental observations on the examined molecules.
HYBRID SOL-GEL ELECTRO-OPTIC POLYMER MODULATORS: BEATING THE DRIVE VOLTAGE/LOSS TRADEOFF
Authors: NORWOOD R. A. , DEROSE C. , ENAMI Y. , GAN H. , GREENLEE C. , HIMMELHUBER R. , KROPACHEV O. , LOYCHIK C. , MATHINE D. , MERZYLAK Y. , FALLAHI M. , PEYGHAMBARIAN N.
Published: July 2007

There has been great progress in the development of electro-optic (EO) polymers with exceptionally high r33 coefficients, with values ranging from 100–400 pm/V now being reported for single layer electro-optic polymer films. While this enables the fabrication of EO modulators with sub-volt operation, it is also necessary to make devices with acceptably low insertion loss (< 6 dB) in order to compete with existing technology. We have developed a solution to the voltage/insertion loss tradeoff in EO polymer modulators by adopting a hybrid geometry that provides for low optical coupling loss, electro-optic polymer limited propagation loss, highly efficient poling, and low cost fabrication. This combination of properties has allowed us to achieve r 33 = 170 pm/V in an EO phase modulator. In addition to this proven approach to optimizing the figure of merit, there are several other approaches that can have high impact. The development of low loss EO polymer and cladding materials and waveguides can greatly reduce the insertion loss of EO polymer modulators, through chemical substitution techniques such as selective halogenation, as well as through improved processing to reduce roughness, stress and poling induced losses. Halogenation can be used to reduce the number of C – H bonds, which have well-known stretch and bend vibrational modes whose overtones extend into the optical communications bands at 1550 nm and 1310 nm. While roughness and stress effects are well-understood from work on passive waveguides, the poling process can produce inhomogeneities that lead to increased scattering loss; molecular design can be used to reduce poling induced loss. Another approach is to adopt non-waveguide device formats that are more tolerant of material losses, such as Fabry-Perot etalons. While etalons may not be viable for very high speed applications (i.e., GHz regime), they present entirely new application areas for electro-optic polymers.
Transport of Sequence-Specific RNA Interference Information Between Cells
Authors: Jose Antony M. , Hunter Craig P.
Published: July 2007

When eukaryotic cells encounter double-stranded RNA, genes of matching sequence are silenced through RNA interference. Surprisingly, in some animals and plants, the same gene is specifically silenced even in cells that did not encounter the double-stranded RNA, due to the transport of a gene-specific silencing signal between cells. This silencing signal likely has an RNA component that gives it sequence-specificity, however its precise identity remains unknown. Studies in the worm Caenorhabditis elegans and in plants have revealed parts of a complex protein machinery that transports this silencing signal. Some of these proteins are conserved in vertebrates, including mammals, raising the possibility that higher animals can communicate gene-specific silencing information between cells. Such communication provides antiviral immunity in plants and perhaps in C. elegans. Identifying the transported silencing signal and deciphering the evolutionarily selected role of the transport machinery are some of the key challenges for the future.
The Death of Socialist Law?
Authors: Markovits Inga
Published: July 2007

Before the collapse of socialism, Western comparative lawyers more or less agreed that socialist law was different from the law of capitalist legal systems. But was it different enough no longer to have a place in the new democracies of Eastern Europe? This review looks at the socialist features of pre-1989 East European law and suggests that Marxist law never existed in the first place; that the Stalinist aspects of socialist law, while not extinct, were not confined to the law of Eastern Europe and thus not necessarily socialist; and that the parental qualities of law in the former Soviet Bloc correspond well not only with the needs of unsettled and impoverished populations in Eastern Europe, but with the modern welfare state in general.
Estrogen increases smooth muscle expression of α2C-adrenoceptors and cold-induced constriction of cutaneous arteries
Authors: Eid A. H. , Maiti K. , Mitra S. , Chotani M. A. , Flavahan S. , Bailey S. R. , Thompson-Torgerson C. S. , Flavahan N. A.
Published: July 2007

Raynaud's phenomenon, which is characterized by intense cold-induced constriction of cutaneous arteries, is more common in women compared with men. Cold-induced constriction is mediated in part by enhanced activity of α2C-adrenoceptors (α2C-ARs) located on vascular smooth muscle cells (VSMs). Experiments were therefore performed to determine whether 17β-estradiol regulates α2C-AR expression and function in cutaneous VSMs. 17β-Estradiol (0.01–10 nmol/l) increased expression of the α2C-AR protein and the activity of the α2C-AR gene promoter in human cultured dermal VSMs, which was assessed following transient transfection of the cells with a promoter-reporter construct. The effect of 17β-estradiol was associated with increased accumulation of cAMP and activation of the cAMP-responsive Rap2 GTP-binding protein. Transient transfection of VSMs with a dominant-negative mutant of Rap2 inhibited the 17β-estradiol-induced activation of the α2C-AR gene promoter, whereas a constitutively active mutant of Rap2 increased α2C-AR promoter activity. The effects of 17β-estradiol were inhibited by the estrogen receptor (ER) antagonist, ICI-182780 (1 μmol/l), and were mimicked by a cell-impermeable form of the hormone (estrogen:BSA) or by the selective ER-α receptor agonist 4,4′,4‴-(4-propyl-[1H]-pyrazole-1,3,5-triyl)tris-phenol (PPT; 10 nmol/l) or the selective ER-β receptor agonist 2,3-bis(4-hydroxyphenyl)-propionitrile (DPN; 10 nmol/l). Therefore, 17β-estradiol increased expression of α2C-ARs by interacting with cell surface receptors to cause a cAMP/Rap2-dependent increase in α2C-AR transcription. In mouse tail arteries, 17β-estradiol (10 nmol/l) increased α2C-AR expression and selectively increased the cold-induced amplification of α2-AR constriction, which is mediated by α2C-ARs. An estrogen-dependent increase in expression of cold-sensitive α2C-ARs may contribute to the increased activity of cold-induced vasoconstriction under estrogen-replete conditions.
Mesenchymal stem cells from ischemic heart disease patients improve left ventricular function after acute myocardial infarction
Authors: Grauss Robert W. , Winter Elizabeth M. , van Tuyn John , Pijnappels Daniël A. , Steijn Rebecca Vicente , Hogers Bianca , van der Geest Rob J. , de Vries Antoine A. F. , Steendijk Paul , van der Laarse Arnoud , Gittenberger-de Groot Adriana C. , Schalij Martin J. , Atsma Douwe E.
Published: July 2007

Mesenchymal stem cells (MSCs) from healthy donors improve cardiac function in experimental acute myocardial infarction (AMI) models. However, little is known about the therapeutic capacity of human MSCs (hMSCs) from patients with ischemic heart disease (IHD). Therefore, the behavior of hMSCs from IHD patients in an immune-compromised mouse AMI model was studied. Enhanced green fluorescent protein-labeled hMSCs from IHD patients (hMSC group: 2 × 105cells in 20 μl, n = 12) or vehicle only (medium group: n = 14) were injected into infarcted myocardium of NOD/ scid mice. Sham-operated mice were used as the control ( n = 10). Cardiac anatomy and function were serially assessed using 9.4-T magnetic resonance imaging (MRI); 2 wk after cell transplantation, immunohistological analysis was performed. At day 2, delayed-enhancement MRI showed no difference in myocardial infarction (MI) size between the hMSC and medium groups (33 ± 2% vs. 36 ± 2%; P = not significant). A comparable increase in left ventricular (LV) volume and decrease in ejection fraction (EF) was observed in both MI groups. However, at day 14, EF was higher in the hMSC than in the medium group (24 ± 3% vs. 16 ± 2%; P < 0.05). This was accompanied by increased vascularity and reduced thinning of the infarct scar. Engrafted hMSCs (4.1 ± 0.3% of injected cells) expressed von Willebrand factor (16.9 ± 2.7%) but no stringent cardiac or smooth muscle markers. hMSCs from patients with IHD engraft in infarcted mouse myocardium and preserve LV function 2 wk after AMI, potentially through an enhancement of scar vascularity and a reduction of wall thinning.
Optical mapping system with real-time control capability
Authors: Iravanian Shahriar , Christini David J.
Published: July 2007

Real-time, closed-loop intervention is an emerging experiment-control method that promises to provide invaluable new insight into cardiac electrophysiology. One example is the investigation of closed-loop feedback control of cardiac activity (e.g., alternans) as a possible method of preventing arrhythmia onset. To date, such methods have been investigated only in vitro using microelectrode systems, which are hindered by poor spatial resolution and are not well suited for atrial or ventricular tissue preparations. We have developed a system that uses optical mapping techniques and an electrical stimulator as the sensory and effector arms, respectively, of a closed-loop, real-time control system. The system consists of a 2,048 × 1 pixel line-scan charge-coupled device camera that records optical signals from the tissue. Custom-image processing and control software, which is implemented on top of a hard real-time operation system (RTAI Linux), process the data and make control decisions with a deterministic delay of <1 ms. The system is tested in two ways: 1) it is used to control, in real time, simulated optical signals of electrical alternans; and 2) it uses precisely timed, feedback-controlled initiation of antitachycardia pacing to terminate reentrant arrhythmias in an arterially perfused swine right ventricle stained with voltage-sensitive fluorescent dye 4{β-[2-(di- n-butylamino)-6-napathy]vinyl}pyridinium (di-4-ANEPPS). Thus real-time control of cardiac activity using optical mapping techniques is feasible. Such a system is attractive because it offers greater measurement resolution than the electrode-based systems with which real-time control has been used previously.
Progression of myocardial injury during coronary occlusion in the collateral-deficient heart: a non-wavefront phenomenon
Authors: Leshnower Bradley G. , Sakamoto Hiroaki , Hamamoto Hirotsugu , Zeeshan Ahmad , Gorman Joseph H. , Gorman Robert C.
Published: July 2007

It is widely accepted that, during acute coronary occlusion, ischemic cell death progresses from the subendocardium to the subepicardium in a wavefront fashion. This concept, which implies that the subendocardium is the most susceptible myocardial region to ischemic injury, was established using a canine model with an extensive system of subepicardial coronary collaterals. In humans, particularly in those with coronary artery disease, there is a wide range in the distribution and functional capacity of the collateral circulation, which may affect the pattern of infarct evolution. Using an ovine model with a limited system of preformed subendocardial coronary collaterals, we characterized the effect of increasing lengths of ischemia on regional blood flow and infarct size in three regions of the ventricular wall: subendocardium, midmyocardium, and subepicardium. Our results demonstrate that the myocardium and microvasculature in these three regions are equally susceptible to injury after 45 min of ischemia. When ischemic time is increased to 1 h, infarct size in the midmyocardium (90 ± 2%) is greater than in the subendocardium (76 ± 4%, P = 0.004) and subepicardium (84 ± 3%, P = 0.13). Microvascular dysfunction as assessed as a percentage of baseline flow is also greater in the midmyocardium (14 ± 5%) compared with the subendocardium (20 ± 3%, P = 0.23) and subepicardium (51 ± 9%, P = 0.007). These findings suggest that, in subjects with a limited system of coronary collateral circulation, the midmyocardium is the most susceptible myocardial region to ischemia and the subendocardium is the most resistant. Myocardial viability during coronary occlusion appears to be primarily determined by the distribution and functional capacity of the collateral circulation.
Smooth muscle cell rigidity and extracellular matrix organization influence endothelial cell spreading and adhesion formation in coculture
Authors: Wallace Charles S. , Strike Sophie A. , Truskey George A.
Published: July 2007

Efforts to develop functional tissue-engineered blood vessels have focused on improving the strength and mechanical properties of the vessel wall, while the functional status of the endothelium within these vessels has received less attention. Endothelial cell (EC) function is influenced by interactions between its basal surface and the underlying extracellular matrix. In this study, we utilized a coculture model of a tissue-engineered blood vessel to evaluate EC attachment, spreading, and adhesion formation to the extracellular matrix on the surface of quiescent smooth muscle cells (SMCs). ECs attached to and spread on SMCs primarily through the α5β1-integrin complex, whereas ECs used either α5β1- or αvβ3-integrin to spread on fibronectin (FN) adsorbed to plastic. ECs in coculture lacked focal adhesions, but EC α5β1-integrin bound to fibrillar FN on the SMC surface, promoting rapid fibrillar adhesion formation. As assessed by both Western blot analysis and quantitative real-time RT-PCR, coculture suppressed the expression of focal adhesion proteins and mRNA, whereas tensin protein and mRNA expression were elevated. When attached to polyacrylamide gels with similar elastic moduli as SMCs, focal adhesion formation and the rate of cell spreading increased relative to ECs in coculture. Thus, the elastic properties are only one factor contributing to EC spreading and focal adhesion formation in coculture. The results suggest that the softness of the SMCs and the fibrillar organization of FN inhibit focal adhesions and reduce cell spreading while promoting fibrillar adhesion formation. These changes in the type of adhesions may alter EC signaling pathways in tissue-engineered blood vessels.
Hydrogen peroxide mediates a transient vasorelaxation with tempol during oxidative stress
Authors: Chen Yifan , Pearlman Adam , Luo Zaiming , Wilcox Christopher S.
Published: July 2007

Tempol catalyzes the formation of H2O2from superoxide and relaxes blood vessels. We tested the hypothesis that the generation of H2O2by tempol in vascular smooth muscle cells during oxidative stress contributes to the vasorelaxation. Tempol and nitroblue tetrazolium (NBT) both metabolize superoxide in vascular smooth muscle cells, but only tempol generates H2O2. Rat pressurized mesenteric arteries were exposed for 20 min to the thromboxane-prostanoid receptor agonist, U-46619, or norepinephrine. During U-46619, tempol caused a transient dilation (22 ± 2%), whereas NBT was ineffective (2 ± 1%), and neither dilated vessels constricted with norepinephrine, which does not cause vascular oxidative stress. Neither endothelium removal nor blockade of K+channels with 40 mM KCl affected the tempol-induced dilation, but catalase blunted the tempol dilation by 53 ± 7%. Tempol, but not NBT, increased H2O2in rat mesenteric vessels detected with dichlorofluorescein. To test physiological relevance in vivo, topical application of tempol caused a transient dilation (184 ± 20%) of mouse cremaster arterioles exposed to angiotensin II for 30 min, which was not seen with NBT (9 ± 4%). The vasodilation to tempol was reduced by 68 ± 6% by catalase. We conclude that the transient relaxation of blood vessels by tempol after prolonged exposure to U-46619 or angiotensin II is mediated in part via production of H2O2and is largely independent of the endothelium and potassium channels.
Influence of plasma osmolality on baroreflex control of sympathetic activity
Authors: Wenner Megan M. , Rose William C. , Delaney Erin P. , Stillabower Michael E. , Farquhar William B.
Published: July 2007

The purpose of this study was to determine if plasma osmolality alters baroreflex control of sympathetic activity when controlling for a change in intravascular volume; we hypothesized that baroreflex control of sympathetic activity would be greater during a hyperosmotic stimulus compared with an isoosmotic stimulus when intravascular volume expansion was matched. Seven healthy subjects (25 ± 2 yr) completed two intravenous infusions: a hypertonic saline infusion (HSI; 3% NaCl) and, on a separate occasion, an isotonic saline infusion (ISO; 0.9% NaCl), both at a rate of 0.15 ml·kg−1·min−1. To isolate the effect of osmolality, comparisons between HSI and ISO conditions were retrospectively matched based on hematocrit; therefore, baroreflex control of sympathetic outflow was determined at 20 min of a HSI and 40 min of an ISO. Muscle sympathetic outflow (MSNA) was directly measured using the technique of peroneal microneurography; osmolality and blood pressure (Finometer) were assessed. The baroreflex control of sympathetic outflow was estimated by calculating the slope of the relationship between MSNA and diastolic blood pressure during controlled breathing. Plasma osmolality was greater during the HSI compared with the ISO (HSI: 292 ± 0.9 mosmol/kg and ISO: 289 ± 0.8 mosmol/kg, P < 0.05). Hematocrits were matched (HSI: 39.1 ± 1% and ISO: 39.1 ± 1%, P > 0.40); thus, we were successful in isolating osmolality. The baroreflex control of sympathetic outflow was greater during the HSI compared with the ISO (HSI: −8.3 ± 1.2 arbitrary units·beat−1·mmHg−1vs. ISO: −4.0 ± 0.8 arbitrary units·beat−1·mmHg−1, P = 0.01). In conclusion, when controlling for intravascular volume, increased plasma osmolality enhances baroreflex control of sympathetic activity in humans.
Aldosterone modulatesIfcurrent through gene expression in cultured neonatal rat ventricular myocytes
Authors: Muto Takao , Ueda Norihiro , Opthof Tobias , Ohkusa Tomoko , Nagata Kohzo , Suzuki Shinsuke , Tsuji Yukiomi , Horiba Mitsuru , Lee Jong-Kook , Honjo Haruo , Kamiya Kaichiro , Kodama Itsuo , Yasui Kenji
Published: July 2007

Mineralocorticoid receptor (MR) antagonists decrease the incidence of sudden cardiac death in patients with heart failure, as has been reported in two clinical trials (Randomized Aldactone Evaluation Study and Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study). Aldosterone has been shown to increase the propensity to arrhythmias by changing the expression or function of various ion channels. In this study, we investigate the effect of aldosterone on the expression of hyperpolarization-activated current ( If) channels in cultured neonatal rat ventricular myocytes, using the whole cell patch-clamp technique, real-time PCR, and Western blotting. Incubation with 10 nM aldosterone for 17–24 h significantly accelerates the rate of spontaneous beating by increasing diastolic depolarization. Ifcurrent elicited by hyperpolarization from −50 to −130 mV significantly increases aldosterone by 10 nM (by 1.9-fold). Exposure to aldosterone for 1.5 h increases hyperpolarization-activated cyclic nucleotide-gated (HCN) 2 mRNA by 26.3% and HCN4 mRNA by 47.2%, whereas HCN1 mRNA expression remains unaffected. Aldosterone (24-h incubation) increases the expression of HCN2 protein (by 60.0%) and HCN4 protein (by 84.8%), but not HCN1 protein. MR antagonists (1 μM eplerenone or 0.1 μM spironolactone) abolish the increase of Ifchannel expression (currents, mRNA, and protein levels) by 10 nM aldosterone. In contrast, 1 μM aldosterone downregulated Ifchannel gene expression. Glucocorticoid receptor antagonist (100 nM RU-38486) did not affect the increase of Ifcurrent by 10 nM aldosterone. These findings suggest that aldosterone in physiological concentrations upregulates Ifchannel gene expression by MR activation in cardiac myocytes and may increase excitability, which may have a potential proarrhythmic bearing under pathophysiological conditions.
CAT-2 amplifies the agonist-evoked force of airway smooth muscle by enhancing spermine-mediated phosphatidylinositol-(4)-phosphate-5-kinase-γ activity
Authors: Chen Hang , MacLeod Carol , Deng Bijia , Mason Lawrence , Kasaian Marion , Goldman Samuel , Wolf Stan , Williams Cara , Bowman Michael R.
Published: July 2007

We investigated the effect the loss of the CAT-2 gene (CAT-2−/−) has on lung resistance (RL) and tracheal isometric tension. The RLof CAT-2−/− mice at a maximal dose of acetylcholine (ACh) was decreased by 33.66% ( P = 0.05, n = 8) compared with that of C57BL/6 (B6) mice. The isometric tension of tracheal rings from CAT-2−/− mice showed a significant decrease in carbachol (CCh)-induced force generation (33.01%, P < 0.05, n = 8) compared with controls. The isoproterenol- or the sodium nitroprusside-induced relaxation was not affected in tracheal rings from CAT-2−/− mice. The activity of iNOS and arginase in lung tissue lysates of CAT-2−/− mice was indistinguishable from that of B6 mice. Furthermore, the expression of phospholipase-Cβ (PLC-β) and phosphatidylinositol-( 4 )-phosphate-5-kinase-γ (PIP-5K-γ) was examined in the lung tissue of CAT-2−/− and B6 mice. The expression of PIP-5K-γ but not PLC-β was significantly reduced in CAT-2−/− compared with B6 mice. The reduced airway smooth muscle (ASM) contractility to CCh seen in the CAT-2−/− tracheal rings was completely reversed by pretreating the rings with 100 μM spermine. This increase in the CAT-2−/− tracheal ring contraction upon spermine pretreatment correlated with a recovery of the expression of PIP-5K-γ. Our data indicates that CAT-2 exerts control over ASM force development through a spermine-dependent pathway that directly correlates with the expression level of PIP-5K-γ in the lung.
Characterization of slowly inactivating KVα current in rabbit pulmonary neuroepithelial bodies: effects of hypoxia and nicotine
Authors: Fu Xiao Wen , Nurse Colin , Cutz Ernest
Published: July 2007

Pulmonary neuroepithelial bodies (NEB) form innervated cell clusters that express voltage-activated currents and function as airway O2sensors. We investigated A-type K+currents in NEB cells using neonatal rabbit lung slice preparation. The whole cell K+current was slowly inactivating with activation threshold of ∼−30 mV. This current was blocked ∼27% by blood-depressing substance I (BDS-I; 3 μM), a selective blocker of Kv3.4 subunit, and reduced ∼20% by tetraethylammonium (TEA; 100 μM). The BDS-I-sensitive component had an average peak value of 189 ± 14 pA and showed fast inactivation kinetics that could be fitted by one-component exponential function with a time constant of (τ1) 77 ± 10 ms. This Kv slowly inactivating current was also blocked by heteropodatoxin-2 (HpTx-2; 0.2 μM), a blocker of Kv4 subunit. The HpTx-2-sensitive current had an average peak value of 234 ± 23 pA with a time constant (τ) 82 ± 11 ms. Hypoxia (Po2= 15–20 mmHg) inhibited the slowly inactivating K+current by ∼47%, during voltage steps from −30 to +30 mV, and no further inhibition occurred when TEA was combined with hypoxia. Nicotine at concentrations of 50 and 100 μM suppressed the slowly inactivating K+current by ∼24 and ∼40%, respectively. This suppression was not reversed by mecamylamine suggesting a direct effect of nicotine on these K+channels. In situ hybridization experiments detected expression of mRNAs for Kv3.4 and Kv4.3 subunits, while double-label immunofluorescence confirmed membrane localization of respective channel proteins in NEB cells. These studies suggest that the hypoxia-sensitive current in NEB cells is carried by slowly inactivating A-type K+channels, which underlie their oxygen-sensitive potassium currents, and that exposure to nicotine may directly affect their function, contributing to smoking-related lung disease.
Molecular determinants of endothelial transcytosis and their role in endothelial permeability
Authors: Predescu Sanda A. , Predescu Dan N. , Malik Asrar B.
Published: July 2007

Caveolae transcytosis with its diverse mechanisms–fluid phase, adsorptive, and receptor-mediated–plays an important role in the continuous exchange of molecules across the endothelium. We will discuss key features of endothelial transcytosis and caveolae that have been studied recently and have increased our understanding of caveolae function in transcytosis at the molecular level. During transcytosis, caveolae “pinch off” from the plasma membrane to form discrete vesicular carriers that shuttle to the opposite front of endothelial cells, fuse with the plasma membrane, and discharge their cargo into the perivascular space. Endothelial transcytosis exhibits distinct properties, the most important being rapid and efficient coupling of endocytosis to exocytosis on opposite plasma membrane. We address herein the membrane fusion-fission reactions that underlie transcytosis. Caveolae move across the endothelial cells with their cargo predominantly in the fluid phase through an active process that bypasses the lysosomes. Endothelial transcytosis is a constitutive process of vesicular transport. Recent studies show that transcytosis can be upregulated in response to pathological stimuli. Transcytosis via caveolae is an important route for the regulation of endothelial barrier function and may participate in different vascular diseases.
Expression of Autophagy-Associated Genes in Skeletal Muscle: An Experimental Model of Chloroquine-Induced Myopathy
Authors: Kimura Noriyuki , Kumamoto Toshihide , Kawamura Yosuke , Himeno Takahiro , Nakamura Ken-ichro , Ueyama Hidetsugu , Arakawa Ryuki
Published: July 2007

Objective: Chloroquine modulates autophagocytic protein degradation in the lysosome system, thereby inducing the formation of rimmed vacuoles consisting of autophagosomes and autolysosomes in skeletal muscle. The goal of this study was to investigate the contribution of the lysosomal system, particularly autophagosome formation (an autophagic process) at the molecular level, to the abnormal accumulation of vacuoles in an experimental model of chloroquine-induced myopathy. Methods: Histological, immunohistochemical and semiquantitative reverse transcriptase-polymerase chain reaction studies were performed on innervated and denervated rat soleus muscles after treatment with either saline or chloroquine. Results: Accumulation of rimmed vacuoles was observed only in chloroquine-treated denervated muscles. Microtubule-associated protein-1 light chain-3 (LC3) protein and mRNA levels were significantly increased exclusively in denervated muscles from chloroquine-treated rats, whereas Apg5 and Apg12 mRNA levels did not change significantly. Further, the mRNA levels of UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE), which are associated with distal myopathy with rimmed vacuoles showing numerous rimmed vacuoles in its skeletal muscle, were not decreased in denervatedmuscles treated with chloroquine. Conclusions: LC3 mRNA may increase in association with rimmed vacuole formation in denervated muscles from chloroquine-treated rats, suggesting an increase in autophagy at the molecular level. Abnormal accumulation of rimmed vacuoles in this myopathy does not appear to be mediated by inhibition of autophagosome-related genes or GNE gene.
Level of Physical Activity in the Week Preceding an Ischemic Stroke
Authors: Krarup Lars-Henrik , Truelsen Thomas , Pedersen Anders , Lerke Hanne , Lindahl Marianne , Hansen Lotte , Schnohr Peter , Boysen Gudrun
Published: July 2007

Background: Most observational studies investigating physical activity as a risk factor for stroke have concentrated on the years preceding a stroke event. In the present case control study we compared the reported level of physical activity performed during the week preceding an ischemic stroke with that of community controls. Furthermore we calculated the odds ratio for stroke based on the level of physical activity. Subjects and Methods: Patients with an ischemic stroke were recruited consecutively from hospitals covering Copenhagen City. Community controls were recruited among participants of the Copenhagen City Heart Study and matched according to age and gender. The level of physical activity was assessed using The Physical Activity Scale for the Elderly (PASE), which quantifies the amount of physical activity done in the last 7 days. Results: A total of 127 cases and 301 control subjects were included in the study. Mean (±SD) PASE scores for cases were 76.0 ± 46.2 and 119.7 ± 69.4 for controls (p < 0.001). For each 1-point increase in PASE score the odds ratio for ischemic stroke was 0.98 (0.98–0.99), equivalent to an odds ratio of 0.86 (95% CI: 0.82–0.90) for each 10-point increase. Conclusion: Stroke patients are less physically active in the week preceding an ischemic stroke when compared to age- and sex-matched controls. Increasing PASE score was inversely, log-linearly and significantly associated with odds ratio for ischemic stroke.
Subarachnoid Hemorrhage as a Complication of Systemic Lupus Erythematosus
Authors: Baizabal Carvallo J.F. , Cantú Brito C. , Estañol B. , García Ramos G.S.
Published: July 2007

Background: Subarachnoid hemorrhage (SAH) is a rare complication of systemic lupus erythematosus (SLE). Methods: We made a retrospective search for patients with SLE and nontraumatic SAH from 1990 to 2006. Results: We found 10 patients with SLE and primary SAH of a total of 1,077 patients with SLE (0.93%); mean age of onset was 37.4 ± 15.25 years and the mean duration of SLE at the onset of SAH was 98.3 ± 50.32 months. SLEDAI and chronic damage scores were 3.67 ± 5.20 (n = 9) and 2.90 ± 1.45 (n = 10), respectively; 60% of patients had high Hunt-Hess scores and in only 50% of cases a saccular aneurysm was identified. Conclusions: SAH presents in about 1% of SLE patients. Long duration of SLE and chronic damage scores might be associated risk factors.
The Psychobiology of Burnout: Are There Two Different Syndromes?
Authors: Tops Mattie , Boksem Maarten A.S. , Wijers Albertus A. , van Duinen Hiske , Den Boer Johan A. , Meijman Theo F. , Korf Jakob
Published: July 2007

Background: Plasma prolactin levels are sensitive to dopamine and serotonin function, and fatigue. Low cortisol, dopamine and/or serotonin may be involved in burnout and detachment. Methods: In this double-blind within-subject study, we treated 9 female burnout subjects and 9 controls with 35 mg cortisol and placebo orally. We measured state affect and plasma prolactin, oxytocin, cortisol and adrenocorticotropic hormone levels, and administered an attachment questionnaire. Results: The burnout subjects displayed an extreme distribution of basal prolactin levels, displaying higher or lower levels compared to the controls. The low prolactin burnouts had profoundly low attachment scores and tended to have low oxytocin levels. The high prolactin burnout subjects tended to show cortisol-induced decreased prolactin and fatigue, and increased vigor. Conclusion: Results are consistent with the hypothesis that burnout subjects are either characterized by low serotonergic function or by low dopaminergic function, and that the latter group benefits from cortisol replacement. These preliminary results suggest that differentiating between two syndromes may resolve inconsistencies in research on burnout, and be necessary for selecting the right treatment strategy.
A Dose-Escalation Study of Pegylated Liposomal Doxorubicin and Oxaliplatin in Patients with Advanced Solid Tumors
Authors: Kotsakis A. , Kouroussis Ch. , Androulakis N. , Agelaki S. , Kalbakis K. , Vamvakas L. , Vardakis N. , Kalykaki A. , Polyzos A. , Georgoulias V. , Mavroudis D.
Published: July 2007

Purpose: A phase I study was conducted to determine the maximum tolerated doses (MTDs) and dose-limiting toxicities (DLTs) of the pegylated liposomal doxorubicin (PLD) and oxaliplatin combination in patients with advanced solid tumors. Patients and Methods: Forty-five patients with advanced-stage solid tumors received escalating doses of PLD 25–50 mg/m2 as 60-min intravenous (i.v.) infusion and oxaliplatin 80–130 mg/m2 as 2- to 4-hour i.v. infusion on day 1 every 3 weeks without growth factors. Results: MTD was defined at PLD 45 mg/m2 and oxaliplatin 130 mg/m2. Eleven dose levels were evaluated and DLTs were grade 2–3 neutropenia resulting in treatment delays, grade 3 neurotoxicity and nausea/vomiting. A total of 187 cycles were administered with two episodes of febrile neutropenia and one toxic death due to sepsis. Two (4%) and 6 (13%) patients developed grade 4 and 3 neutropenia, respectively, 2 (4%) and 1 (2%) grade 4 and 3 thrombocytopenia, and 1 (2%) grade 4 anemia. The most common nonhematological toxicities were grade 2–3 nausea/vomiting and asthenia observed in 27 (60%) and 16 (36%) of patients, respectively. One complete and eight partial responses were observed. Conclusion: The combination of PLD and oxaliplatin has an acceptable toxicity profile with promising activity and merits further evaluation in phase II studies.
Prognostic Value of Carcinoembryonic Antigen and Vascular Endothelial Growth Factor Tumor Tissue Content in Colorectal Cancer
Authors: Ferroni Patrizia , Palmirotta Raffaele , Spila Antonella , Martini Francesca , Formica Vincenzo , Portarena Ilaria , Del Monte Girolamo , Buonomo Oreste , Roselli Mario , Guadagni Fiorella
Published: July 2007

Aim: This study was designed to assess the prognostic significance of the combined measurement of vascular endothelial growth factor (VEGF) and carcinoembryonic antigen (CEA) tissue content with respect to relapse-free and overall survival of patients with colorectal cancer (CRC). Methods: Quantitative evaluation of VEGF and CEA content was performed on protein extracts obtained from tissue biopsies from 69 CRC patients and 15 healthy donors. Results: VEGF significantly correlated with CEA content of either tumor tissues (rho = 0.55, p < 0.0001) or corresponding normal mucosa (rho = 0.34, p < 0.005). General regression analyses demonstrated that CEA was an independent predictor of VEGF tissue content either in CRC biopsies (regression coefficient = 0.57, p < 0.0001) or normal mucosa (regression coefficient = 0.25, p < 0.05). Cox proportional hazards survival analysis showed that tumor tissue content of both VEGF and CEA had an independent prognostic value in predicting both relapse-free (hazards ratio = 5.98, p = 0.002) and overall (hazards ratio = 4.73, p = 0.007) survival, irrespective of Dukes’ stage. Kaplan-Meier analysis demonstrated that an elevated tumor content of both CEA and VEGF had a negative prognostic value in respect to either relapse-free (log-rank test: 10.4, p = 0.001) or overall survival (log-rank test: 7.33, p = 0.007). Conclusion: Tumor tissue VEGF and CEA content determination might add useful prognostic information in the management of patients with CRC.
The Role of NGX6 and Its Deletion Mutants in the Proliferation, Adhesion and Migration of Nasopharyngeal Carcinoma 5-8F Cells
Authors: Peng Shu-Ping , Li Xiao-Ling , Wang Li , Ou-yang Jue , Ma Jian , Wang Li-Li , Liu Hua-Ying , Zhou Ming , Tang Yun-Lian , Li Wei-Song , Luo Xiao-Min , Cao Li , Tang Ke , Shen Shou-Rong , Li Gui-Yuan
Published: July 2007

Objective: To demonstrate the subcellular localization of nasopharyngeal carcinoma (NPC)-associated gene 6 (NGX6) and its basic structure and function. Methods: The deletion mutants of NGX6 were constructed by one-step PCR and transfected into NPC cell line 5-8F. The subcellular location of NGX6 or its mutants was detected by immunofluorescence staining of cytoplasm (CYTO) and nuclear protein, and immunoelectron-microscopic analysis. The role of NGX6 and its mutants in the proliferation, adhesion and migration of NPC 5-8F cells was detected using the following assays: growth curve, colony formation in soft agar, cell adhesion, in vitro Matrigel invasion, and in vitro scratch wound healing. Results and Conclusions: NGX6 and its mutants were distributed on the plasma membrane, nuclear membrane, endoplasmic reticulum membrane, and other membrane structures in the cytosol. The deleted domains did not affect its distribution in 5-8F cells. NGX6 could increase the adhesion but inhibited the proliferation, growth and migration of 5-8F cells. The epidermal growth factor-like domain and CYTO region were found to be important for NGX6 to modulate cell adhesion, and CYTO was found to be essential for NGX6 involved in the regulation of growth, proliferation, and migration of 5-8F cells.