bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of the UDP-
N
-Acetylglucosamine 4-Epimerase Involved in Exosporium Protein Glycosylation in
Bacillus anthracis
Authors: Dong Shengli , Chesnokova Olga N. , Turnbough Charles L. , Pritchard David G.
Published: September 2009

Spores of
Bacillus anthracis
, the causative agent of anthrax, are enclosed by a loosely fitting exosporium composed of a basal layer and an external hair-like nap. The filaments of the nap are formed by trimers of the collagen-like glycoprotein BclA. The side chains of BclA include multiple copies of two linear rhamnose-containing oligosaccharides, a trisaccharide and a pentasaccharide. The pentasaccharide terminates with the unusual deoxyamino sugar anthrose. Both oligosaccharide side chains are linked to the BclA protein backbone through an
N
-acetylgalactosamine (GalNAc) residue. To identify the gene encoding the epimerase required to produce GalNAc for BclA oligosaccharide biosynthesis, three annotated UDP-glucose 4-epimerase genes of
B. anthracis
were cloned and expressed in
Escherichia coli
. The candidate proteins were purified, and their enzymatic activities were assessed. Only two proteins, encoded by the BAS5114 and BAS5304 genes (
B. anthracis
Sterne designations), exhibited epimerase activity. Both proteins were able to convert UDP-glucose (Glc) to UDP-Gal, but only the BAS5304-encoded protein could convert UDP-GlcNAc to UDP-GalNAc, indicating that BAS5304 was the gene sought. Surprisingly, spores produced by a mutant strain lacking the BAS5304-encoded enzyme still contained normal levels of BclA-attached oligosaccharides. However, monosaccharide analysis of the oligosaccharides revealed that GlcNAc had replaced GalNAc. Thus, while GalNAc appears to be the preferred amino sugar for the linkage of oligosaccharides to the BclA protein backbone, in its absence, GlcNAc can serve as a substitute linker. Finally, we demonstrated that the expression of the BAS5304 gene occurred in a biphasic manner during both the early and late stages of sporulation.
Assessment of sentinel lymph node in cervical cancer: review of literature: Figure 1
Authors: Rasty G , Hauspy J , Bandarchi B
Published: September 2009

Sentinel lymph node biopsy is a novel method for the surgical management of patients with cervical cancer. Sentinel nodes have a higher chance of harbouring metastases than non-sentinel nodes. Assessment of sentinel nodes provides an opportunity to stage patients intraoperatively and avoid complete pelvic lymph node dissection and hence its morbidities. The aim of this article is to review the diagnostic performance of sentinel node detection, to determine which technique (blue dye, Tc or both) has the highest detection rate and sensitivity, and also to illustrate different approaches of histological assessment of the sentinel lymph node biopsy.
Achieving fire-safe cigarette legislation through coalition-based legislative advocacy: Figure 1
Authors: Goldstein Adam O , Grant Ernest , McCullough Anna , Cairns Bruce , Kurian Ann
Published: September 2009

Advocates who work for tobacco control legislation through coalition-based policy advocacy have access to a broad base of support and resources that are critical to overcoming the tobacco industry lobby. This article provides an example of how a coalition-based advocacy strategy that engaged a diverse group of stakeholders and was supported by a national coordinating movement achieved state level fire-safe cigarette legislation in a tobacco-producing and manufacturing state.
Adverse effects of a social contract smoking prevention program among children in Québec, Canada
Authors: Kairouz S , O’Loughlin J , Laguë J
Published: September 2009

Objective:

To evaluate the impact of a smoke-free class competition in elementary schools in Québec, Canada before widespread dissemination of the program across the province.

Methods:

In a quasiexperimental study design, 843 students in 27 schools exposed to “Mission TNT.06” were compared to 1213 students in 57 matched comparison schools. Baseline data were collected in grade 6 prior to implementation of the program. Follow-up data were collected in grade 7 after students had transitioned to secondary school.

Results:

The program improved knowledge about the harmful effects of second-hand smoke, but had no impact on knowledge about the harmful effects of smoking, attitudes about the acceptability of cigarettes, beliefs about the tobacco industry, or self-efficacy to resist peer pressure to smoke. After exposure to the program, intervention students were more likely to misreport their smoking status and to report unfavourable attitudes about classmates who smoke.

Conclusion:

Mission TNT.06 may encourage young smokers to misreport their smoking status and to marginalise classmates who smoke. These findings prompted recommendations to conduct more in-depth evaluation of the smoke-free class competition before widespread dissemination of the program across the province.
Smoking-attributable deaths and potential years of life lost from a large, representative study in China
Authors: Jiang Jingmei , Liu Boqi , Sitas Freddy , Li Junyao , Zeng Xianjia , Han Wei , Zou Xiaonong , Wu Yanping , Zhao Ping
Published: September 2009

Objectives

To provide a more accurate estimate of early smoking-attributable mortality and potential years of life lost using data from a representative study of 103 study areas in China.

Methods

Two datasets were employed as follows. Firstly, retrospective national mortality survey data, which included a population of 67 million in 103 study areas, and about 1 million adults who died in 1986–1988; secondly, nationally representative case-control comparative data was extracted from the survey data to measure the effect of smoking on age trends in smoking-attributable mortality. Potential years of life lost, and sex differences in life expectancy in smokers and non-smokers in the total population aged 35 and over were also estimated.

Results

Tobacco caused 11.2% (16.0% of men and 3.7% of women) of total deaths in 1987, and more than two-thirds of these excess deaths occurred between the ages of 50 and 74 years, but only less than 5% excess deaths occurred at ages under 50. Although life expectancies varied with region or sex differences, the years of life lost attributable to smoking was almost the same. Smokers at age 35 lost about 3 years of life expectancy in comparison with never smokers. The study also confirmed that more than 50% of the sex difference in life expectancy was accounted for by smoking.

Conclusion

Fully understanding the consequences of smoking in relation to mortality can clarify its effects on the health and longevity of the entire population.
Smoke-free homes in England: prevalence, trends and validation by cotinine in children
Authors: Jarvis M J , Mindell J , Gilmore A , Feyerabend C , West R
Published: September 2009

Objective:

To examine the prevalence of smoke-free homes in England between 1996 and 2007 and their impact on children’s exposure to second-hand smoke via a series of annual cross-sectional surveys: the Health Survey for England. These comprised nationally representative samples of non-smoking children aged 4–15 (n = 13 365) and their parents interviewed in the home. Main outcome measures were cotinine measured in saliva, smoke-free homes defined by “no” response to “Does anyone smoke inside this house/flat on most days?”, self-reported smoking status of parents and self-reported and cotinine validated smoking status in children.

Results:

The proportion of homes where one parent was a smoker that were smoke free increased from 21% in 1996 to 37% in 2007, and where both parents were smokers from 6% to 21%. The overwhelming majority of homes with non-smoking parents were smoke free (95% in 1996; 99% in 2007). For children with non-smoking parents and living in a smoke-free home the geometric mean cotinine across all years was 0.22 ng/ml. For children with one smoking parent geometric mean cotinine levels were 0.37 ng/ml when the home was smoke free and 1.67 ng/ml when there was smoking in the home; and for those with two smoking parents, 0.71 ng/ml and 2.46 ng/ml. There were strong trends across years for declines in cotinine concentrations in children in smoke-free homes for the children of smokers and non-smokers.

Conclusions:

There has been a marked secular trend towards smoke-free homes, even when parents themselves are smokers. Living in a smoke-free home offers children a considerable, but not complete, degree of protection against exposure to parental smoking.
Regulating the tobacco retail environment: beyond reducing sales to minors: Table 1
Authors: Chapman S , Freeman B
Published: September 2009

The World Health Organization Framework Convention on Tobacco Control (FCTC) has little to say about the regulation of tobacco retailing, with most research and policy debate having been restricted to confining sales to adults and removing advertising displays, including packs. Tobacco retailing is largely unregulated, reflecting the historical regulatory trivialisation of tobacco products, now demonstrably anachronistic with the advent of near global support for the FCTC. This situation contrasts markedly with the regulation of pharmaceuticals, and many other goods and services subject to a wide variety of restrictions. This review proposes that the international tobacco control community should open up debate on retail regulation to examine the suitability of principles long accepted in pharmaceutical regulation. These include: restrictions on the number and location of tobacco retail outlets, the banning of tobacco retail displays, floor (minimum) price controls, restricting the amount of tobacco smokers could purchase over a given time and loss of retail licensure following breaches of any of the conditions of license. It proposes that retail licenses should be heavily restricted and tradable, becoming valuable commercial assets, where the threat of loss or revocation would act as an incentive for strict adherence to the measures proposed.
A cross-sectional study on levels of secondhand smoke in restaurants and bars in five cities in China
Authors: Liu R L , Yang Y , Travers M J , Fong G T , O'Connor R J , Hyland A , Li L , Nan Y , Feng G Z , Li Q , Jiang Y
Published: September 2009

Objectives

To assess indoor secondhand smoke (SHS) exposure in restaurants and bars via PM2.5level measurements in five cities in China.

Methods

The study was conducted from July to September in 2007 in Beijing, Xi'an, Wuhan, Kunming and Guiyang. PM2.5concentrations were measured in 404 restaurants and bars using portable aerosol monitors. The occupant density and the active smoker density were calculated for each venue sampled.

Results

Among the 404 surveyed venues, 23 had complete smoking bans, nine had partial smoking bans and 313 (77.5%) had smoking observed during sampling. The geometric mean of indoor PM2.5levels in venues with smoking observed was 208 μg/m3and 99 μg/m3in venues without smoking observed. When outdoor PM2.5levels were adjusted, indoor PM2.5levels in venues with smoking observed were consistently significantly higher than those in venues without smoking observed (F=80.49, p<0.001). Indoor PM2.5levels were positively correlated with outdoor PM2.5levels (partial ρ=0.37 p<0.001) and active smoker density (partial ρ=0.34, p<0.001).

Conclusions

Consistent with findings in other countries, PM2.5levels in smoking places are significantly higher than those in smoke-free places and are strongly related to the number and density of active smokers. These findings document the high levels of SHS in hospitality venues in China and point to the urgent need for comprehensive smoke-free laws in China to protect the public from SHS hazards, as called for in Article 8 of the Framework Convention on Tobacco Control, which was ratified by China in 2005.
Phytoplankton productivity across prairie saline lakes of the Great Plains (USA): a step toward deciphering patterns through lake classification models
Authors: Salm Courtney R. , Saros Jasmine E. , Fritz Sherilyn C. , Osburn Christopher L. , Reineke David M.
Published: September 2009

We investigated patterns of primary production across prairie saline lakes in the central and northern Great Plains of the United States. Based on comparative lake sampling in 2004, seasonal predictors of algal primary productivity were identified within subsets of similar lakes using a combination of Akaike’s information criterion (AIC) and classification and regression trees (CART). These models indicated complex patterns of nutrient limitation by nitrogen (N), phosphorus (P), and iron (Fe) within different lake groups. Nutrient enrichment assays (control, + Fe, + N, + P, + N + P) were performed in spring and summer of 2006 to determine if phytoplankton in selected lakes followed predicted patterns of nutrient limitation. Both the comparative lake sampling and experimental results indicated that N limitation was widespread in these prairie lakes, with evidence for secondary P limitation in certain lakes. In the experiments, iron did not stimulate primary production. Our results suggest that given the diverse geochemical nature of these lakes, classification models that separate saline lakes into subsets may be an effective method for improving predictions of algal production.
Rainbow trout (Oncorhynchus mykiss) invasion in Hokkaido streams, northern Japan, in relation to flow variability and biotic interactions
Authors: Inoue Mikio , Miyata Hiroshi , Tange Yousuke , Taniguchi Yoshinori
Published: September 2009

Factors controlling invasion success of rainbow trout ( Oncorhynchus mykiss ) and interactions with native masu salmon ( Oncorhynchus masou ) were examined by field investigations. The results suggested that flow regime has a major role in controlling rainbow trout invasion success. Although competitive relationships were found between the two species, masu salmon were not likely to prevent trout invasion. Analyses on the distributions and abundances of the two species indicated that the occurrence of rainbow trout was limited to streams with stable flows, and the density of each species was negatively related with that of the other. Habitat use and diet analyses revealed a pattern of their resource partitioning; rainbow trout occupy positions near the bottom or cover, foraging benthic prey, while masu salmon feed drifting prey at the middle layers of the water column. This resource partitioning was suggested to reflect a diet shift by rainbow trout. Our results also have a management implication that dams, which control flow regime, can be a key factor in managing rainbow trout invasion and its effects.
Striking the right balance in right whale conservation
Authors: Schick Robert S. , Halpin Patrick N. , Read Andrew J. , Slay Christopher K. , Kraus Scott D. , Mate Bruce R. , Baumgartner Mark F. , Roberts Jason J. , Best Benjamin D. , Good Caroline P. , Loarie Scott R. , Clark James S.
Published: September 2009

Despite many years of study and protection, the North Atlantic right whale ( Eubalaena glacialis ) remains on the brink of extinction. There is a crucial gap in our understanding of their habitat use in the migratory corridor along the eastern seaboard of the United States. Here, we characterize habitat suitability in migrating right whales in relation to depth, distance to shore, and the recently enacted ship speed regulations near major ports. We find that the range of suitable habitat exceeds previous estimates and that, as compared with the enacted 20 nautical mile buffer, the originally proposed 30 nautical mile buffer would protect more habitat for this critically endangered species.
Theoretical and experimental study of infrared spectra of He2-CO2This article is part of a Special Issue on Spectroscopy at the University of New Brunswick in honour of Colan Linton and Ron Lees.
Authors: Tang Jian , McKellar A. R.W. , Wang Xiao-Gang , Carrington Tucker
Published: September 2009

Additional high-resolution lines in the ν3 CO2 fundamental band of the rovibrational spectrum of He2-CO2 have been observed using a tunable infrared laser to probe a pulsed supersonic jet expansion. The ro-vibrational spectrum was calculated using Euler angles and five vibrational coordinates that specify the positions of the He atoms with respect to the CO2 molecule, a product basis, and a Lanczos eigensolver. Rotational states with J = 0, 1, 2, and 3 associated with the vibrational ground state and different states (νt) of the torsional motion of the two He atoms about the CO2 axis are identified and assigned. The assignment is consistent with having different principle axis orientiations in νt = 0 and νt = 1 states. Δνt = 1 infrared transistions are forbidden due to the symmetry of CO2, but Δνt = 1 microwave transistions are possible. Theoretical line positions and intensities are predicted. Good agreement between experiment and theory was obtained. The calculated energy levels and intensities were crucial in assigning some of the weaker observed transitions.
Fourier transform spectra of the ν16, 2ν16, and 2ν16–ν16 bands of pyrrole taken with synchrotron radiationThis article is part of a Special Issue on Spectroscopy at the University of New Brunswick in honour of Colan Linton and Ron Lees.
Authors: Tokaryk D. W. , van Wijngaarden J. A.
Published: September 2009

Rotationally-resolved vibrational spectra of three bands related to the lowest frequency vibration of the five-membered heterocycle pyrrole (c-C4H4NH) have been recorded using infrared light from the Canadian Light Source synchrotron as the source. The N-H out-of-plane wagging fundamental band ν16 (474.6 cm–1) was recorded with 0.001 cm–1 resolution along with the first hot band 2ν16–ν16 (488.1 cm–1). Both are governed by c-type selection rules. The first overtone 2ν16 (962.7 cm–1) was recorded with 0.0013 cm–1 resolution and has a-type rotational structure. A total of 9103 lines were assigned and included in a simultaneous fit of all three bands. The band origins and excited state rotational parameters were well-determined using Watson’s S-reduced Hamiltonian, Ir representation as seen by the low rms error of the global fit: 0.000 172 cm–1.
Sensitivity analyses in snow avalanche dynamics modeling and implications when modeling extreme events
Authors: Borstad Christopher P. , McClung D. M.
Published: September 2009

We present the first snow avalanche dynamics model simulations to start in the middle of the avalanche path at the maximum expected speed for an extreme event. We first present a sensitivity analysis of the dynamics model to the various model inputs. A single-parameter Coulomb-type friction formulation is used in the model. This formulation is supported by various experiments and full-scale observations of avalanche flow that demonstrate a coupling between the shear and normal forces in flowing snow. The dynamics model is shown to be most sensitive to changes in the friction coefficient. We suggest that the precision in the friction coefficient necessary to confidently use a dynamics model to predict runout distances is higher than the current state of knowledge about avalanche resistance mechanisms. This result leads to the new modeling technique that starts numerical simulations at the midpoint of the length of the avalanche path at maximum speed. The Coulomb friction coefficient is chosen to produce a unique speed profile from this new starting point at maximum speed to a state of rest at an empirically pre-determined runout position. The technique reproduces the observed sharp deceleration of avalanche flow in the runout zone.
HIDDEN SCALE IN QUANTUM MECHANICS
Authors: GIRI PULAK RANJAN
Published: September 2009

We show that the intriguing localization of a free particle wave-packet is possible due to a hidden scale present in the system. Self-adjoint extensions (SAE) is responsible for introducing this scale in quantum mechanical models through the nontrivial boundary conditions. We discuss a couple of classically scale invariant free particle systems to illustrate the issue. In this context it has been shown that a free quantum particle moving on a full line may have localized wave-packet around the origin. As a generalization, it has also been shown that particles moving on a portion of a plane or on a portion of a three-dimensional space can have unusual localized wave-packet.
SUSTAINABILITY OF MULTI-FIELD INFLATION AND BOUND ON STRING SCALE
Authors: GONG JINN-OUK
Published: September 2009

We study the effects of the interaction terms between the inflaton fields on the inflationary dynamics in multi-field models. With power law type potential and interactions, the total number of e-folds may get considerably reduced and can lead to unacceptably short period of inflation. Also we point out that this can place a bound on the characteristic scale of the underlying theory such as string theory. Using a simple multi-field chaotic inflation model from string theory, the string scale is constrained to be larger than the scale of grand unified theory. Allowing post-inflationary generation of perturbation can greatly alleviate this constrain.
APPARENT HORIZON AND EVENT HORIZON OF A VAIDYA BLACK HOLE
Authors: ZHOU SHIWEI , LIU WENBIAO
Published: September 2009

Hawking radiation on the apparent horizon of a Vaidya black hole is investigated using Parikh's tunneling method. When back-reaction of particles is neglected, precisely thermal spectrum can be obtained. Then the black hole thermodynamics can be built successfully on the apparent horizon. When a relativistic perturbation is given to the apparent horizon, similar calculation can also lead to a purely thermal spectrum, which is corresponding to a modified temperature from the former. The first law of thermodynamics can also be constructed successfully at a new supersurface which has a small deviation from the apparent horizon. When the event horizon is thought as such a deviation from the apparent horizon, the expressions of the characteristic position and temperature are consistent with the previous viewpoint which asserts that the thermodynamics should be built on the event horizon. It is concluded that the thermodynamics should be constructed on the apparent horizon exactly while the event horizon thermodynamics is just one of the perturbations near the apparent horizon.
FERMIONS' TUNNELS FROM THE SLOWLY VARYING NONSTATIONARY REISSNER–NORDSTRÖM BLACK HOLE
Authors: YANG SHU-ZHENG , LIN KAI , YANG JUAN
Published: September 2009

In this paper, the Hawking radiation from the slowly varying nonstationary Reissner–Nordström black hole is discussed through the fermions tunnelling theory, assuming a reasonable form of gamma matrix, and even researching on the issues with following coordinate transformation, which is a new method to study fermions' Hawking tunnelling radiation from slowly varying nonstationary Reissner–Nordström black hole.
Myocardial ischemia and reperfusion injury is dependent on both IgM and mannose-binding lectin
Authors: Busche Marc N. , Pavlov Vasile , Takahashi Kazue , Stahl Gregory L.
Published: September 2009

Complement activation has been shown to play an important role in the inflammation and tissue injury following myocardial ischemia and reperfusion (MI/R). Several recent studies from our laboratory demonstrated the importance of mannose-binding lectin (MBL) as the initiation pathway for complement activation and the resulting pathological effects following MI/R. However, other studies from the past suggest an important role of the classical pathway and perhaps natural antibodies. In the present study, we used newly generated genetically modified mice that lack secreted IgM (sIgM), MBL-A, and MBL-C (sIgM/MBL null) in a plasma reconstitution mouse model of MI/R. Following 30 min of ischemia and 4 h of reperfusion, left ventricular ejection fractions were significantly higher in sIgM/MBL null mice reconstituted with MBL null or sIgM/MBL null plasma compared with reconstitution with wild-type (WT) plasma or WT mice reconstituted with WT plasma following MI/R. Serum troponin I concentration, myocardial polymorphonuclear leukocyte infiltration, and C3 deposition were dependent on the combined presence of sIgM and MBL. These results demonstrate that MI/R-induced complement activation, inflammation, and subsequent tissue injury require both IgM and MBL. Thus MBL-dependent activation of the lectin pathway may not be completely antibody independent in I/R models.
Extraction of morphometry and branching angles of porcine coronary arterial tree from CT images
Authors: Wischgoll Thomas , Choy Jenny S. , Kassab Ghassan S.
Published: September 2009

The morphometry (diameters, length, and angles) of coronary arteries is related to their function. A simple, easy, and accurate image-based method to seamlessly extract the morphometry for coronary arteries is of significant value for understanding the structure-function relation. Here, the morphometry of large (≥1 mm in diameter) coronary arteries was extracted from computed tomography (CT) images using a recently validated segmentation algorithm. The coronary arteries of seven pigs were filled with Microfil, and the cast hearts were imaged with CT. The centerlines of the extracted vessels, the vessel radii, and the vessel lengths were identified for over 700 vessel segments. The extraction algorithm was based on a topological analysis of a vector field generated by normal vectors of the extracted vessel wall. The diameters, lengths, and angles of the right coronary artery, left anterior descending coronary artery, and left circumflex artery of all vessels ≥1 mm in diameter were tabulated for the respective orders. It was found that bifurcations at orders 9–11 are planar (∼90%). The relations between volume and length and area and length were also examined and found to scale as power laws. Furthermore, the bifurcation angles follow the minimum energy hypothesis but with significant scatter. Some of the applications of the semiautomated extraction of morphometric data in applications to coronary physiology and pathophysiology are highlighted.
Pharmacological modifications of the stretch-induced effects on ventricular fibrillation in perfused rabbit hearts
Authors: Chorro Francisco J. , Trapero Isabel , Such-Miquel Luis , Pelechano Francisca , Mainar Luis , Cánoves Joaquín , Tormos Álvaro , Alberola Antonio , Hove-Madsen Leif , Cinca Juan , Such Luis
Published: September 2009

Stretch induces modifications in myocardial electrical and mechanical activity. Besides the effects of substances that block the stretch-activated channels, other substances could modulate the effects of stretch through different mechanisms that affect Ca2+handling by myocytes. Thirty-six Langendorff-perfused rabbit hearts were used to analyze the effects of the Na+/Ca2+exchanger blocker KB-R7943, propranolol, and the adenosine A2receptor antagonist SCH-58261 on the acceleration of ventricular fibrillation (VF) produced by acute myocardial stretching. VF recordings were obtained with two epicardial multiple electrodes before, during, and after local stretching in four experimental series: control ( n = 9), KB-R7943 (1 μM, n = 9), propranolol (1 μM, n = 9), and SCH-58261 (1 μM, n = 9). Both the Na+/Ca2+exchanger blocker KB-R7943 and propranolol induced a significant reduction ( P < 0.001 and P < 0.05, respectively) in the dominant frequency increments produced by stretching with respect to the control and SCH-58261 series (control = 49.9%, SCH-58261 = 52.1%, KB-R7943 = 9.5%, and propranolol = 12.5%). The median of the activation intervals, the functional refractory period, and the wavelength of the activation process during VF decreased significantly under stretch in the control and SCH-58261 series, whereas no significant variations were observed in the propranolol and KB-R7943 series, with the exception of a slight but significant decrease in the median of the fibrillation intervals in the KB-R7943 series. KB-R7943 and propranolol induced a significant reduction in the activation maps complexity increment produced by stretch with respect to the control and SCH-58261 series. In conclusion, the electrophysiological effects responsible for stretch-induced VF acceleration in the rabbit heart are reduced by the Na+/Ca2+exchanger blocker KB-R7943 and by propranolol but not by the adenosine A2receptor antagonist SCH-58261.
Absence of adenosine-mediated aortic relaxation in A2Aadenosine receptor knockout mice
Authors: Ponnoth Dovenia S. , Sanjani Maryam Sharifi , Ledent Catherine , Roush Kevin , Krahn Thomas , Mustafa S. Jamal
Published: September 2009

Adenosine mediates vascular responses through four receptor subtypes: A1, A2A, A2B, and A3. The role of A2Areceptors in aortic vascular tone was investigated using A2Aadenosine receptor (AR) knockout (A2AKO) and corresponding wild-type (A2AWT) mice. Isolated aortic rings from A2AWT and A2AKO mice were precontracted with phenylephrine (10−7M), and concentration responses for adenosine analogs and selective agonists/antagonists were obtained. Nonselective adenosine analog (NECA; EC50= 6.78 μM) and CGS-21680 (A2AAR selective agonist; EC50= 0.013 μM) produced concentration-dependent relaxation (maximum of 25% and 28% relaxation at 10−5M NECA and CGS-21680, respectively) in A2AWT aorta. In A2AKO aorta, NECA (EC50= 0.075 μM) induced concentration-dependent contraction (maximum contraction of 47% at 10−6M; P < 0.05 compared with A2AWT), whereas CGS-21680 produced no response. SCH-58261 (10−6M; A2AAR selective antagonist) abolished both NECA- and CGS-21680-mediated vasorelaxation in A2AWT ( P < 0.05), whereas no change was observed in A2AKO. When DPCPX (10−5M; A1selective antagonist) was used in NECA concentration response, greater vasorelaxation was observed in A2AWT (50% vs. 25% in controls at 10−5M; P < 0.05), whereas lower contraction was seen in A2AKO tissues (5% vs. 47% in controls at 10−6M; P < 0.05). Aortic endothelial function, determined by response to acetylcholine, was significantly higher in WT compared with KO (66% vs. 51%; P < 0.05). BAY 60–6583 (A2Bselective agonist) produced similar relaxation in both KO and WT tissues. In conclusion, A2AAR KO mice had significantly lower aortic relaxation and endothelial function, suggesting that the A2AAR plays an important role in vasorelaxation, probably through an endothelium-dependent mechanism.
Angiotensin II enhances GABABreceptor-mediated responses and expression in nucleus tractus solitarii of rats
Authors: Zhang Qi , Yao Fanrong , O'Rourke Stephen T. , Qian Steven Y. , Sun Chengwen
Published: September 2009

Angiotensin II (ANG II) increases GABABreceptor expression in neuronal cultures from the nucleus tractus solitarii (NTS). In the present study, the chronic effects of ANG II on GABABreceptor expression and activity were examined in the NTS of Sprague-Dawley rats. Intracerebroventricular infusion of ANG II caused a significant elevation in blood pressure (BP) and an increase in GABABreceptor expression in the NTS. Conversely, chronic NG-nitro-l-arginine methyl ester (l-NAME) treatment also increased BP, but had no effect on GABABreceptor expression in the NTS. Next, we examined the BP response to the GABABreceptor agonist baclofen microinjected into the NTS of ANG II- or artificial cerebrospinal fluid (aCSF)-infused rats. NTS microinjection of baclofen increased BP in both groups of rats. However, the pressor response to baclofen was enhanced in ANG II-infused rats compared with aCSF-infused rats. In addition, bilateral microinjection of the GABABreceptor antagonist CGP-35348 into the NTS evoked a decrease in BP in both group of rats, and the depressor responses to CGP-35348 were enhanced in the ANG II-infused rats. In contrast, the pressor responses to the GABAAreceptor agonist muscimol and the depressor responses to the GABAAreceptor antagonist bicuculline were comparable between aCSF- and ANG II-infused rats. These results indicate that chronic ANG II infusion stimulates GABABreceptor expression and augments GABABreceptor-mediated responses in the NTS. This effect could contribute to the central nervous system actions of ANG II that result in dampening of baroreflexes and elevation in arterial BP.
Vasopressin is a major vasoconstrictor involved in hindlimb vascular responses to stimulation of adenosine A1receptors in the nucleus of the solitary tract
Authors: McClure Joseph M. , Rossi Noreen F. , Chen Haiping , O'Leary Donal S. , Scislo Tadeusz J.
Published: September 2009

Our previous study showed that stimulation of adenosine A1receptors located in the nucleus of the solitary tract (NTS) exerts counteracting effects on the iliac vascular bed: activation of the adrenal medulla and β-adrenergic vasodilation versus vasoconstriction mediated by neural and unknown humoral factors. In the present study we investigated the relative contribution of three major potential humoral vasoconstrictors: vasopressin, angiotensin II, and norepinephrine in this response. In urethane-chloralose anesthetized rats we compared the integral changes in iliac vascular conductance evoked by microinjections into the NTS of the selective A1receptor agonist N6-cyclopentyladenosine (CPA; 330 pmol in 50 nl) in intact (Int) animals and following: V1vasopressin receptor blockade (VX), angiotensin II AT1receptor blockade (ATX), bilateral adrenalectomy + ganglionic blockade (ADX + GX; which eliminated the potential increases in circulating norepinephrine and epinephrine), ADX + GX + VX and ADX + GX + VX + ATX. In Int animals, stimulation of NTS A1adenosine receptors evoked typical variable responses with prevailing pressor and vasoconstrictor effects. VX reversed the responses to depressor ones. ATX did not significantly alter the responses. ADX + GX accentuated pressor and vasoconstrictor responses, whereas ADX + GX + VX and ADX + GX + VX + ATX virtually abolished the responses. Stimulation of NTS A1adenosine receptors increased circulating vasopressin over fourfold (26.4 ± 10.4 vs. 117.0 ± 19 pg/ml). These data strongly suggest that vasopressin is a major vasoconstrictor factor opposing β-adrenergic vasodilation in iliac vascular responses triggered by stimulation of NTS A1adenosine receptors, whereas angiotensin II and norepinephrine do not contribute significantly to the vasoconstrictor responses.
Replicative senescence of vascular smooth muscle cells enhances the calcification through initiating the osteoblastic transition
Authors: Nakano-Kurimoto Ritsuko , Ikeda Koji , Uraoka Maki , Nakagawa Yusuke , Yutaka Kotaro , Koide Masahiro , Takahashi Tomosaburo , Matoba Satoaki , Yamada Hiroyuki , Okigaki Mitsuhiko , Matsubara Hiroaki
Published: September 2009

Medial artery calcification, which does not accompany lipid or cholesterol deposit, preferentially occurs in elderly population, but its underlying mechanisms remain unclear. In the present study, we investigated the potential role of senescent vascular smooth muscle cells (VSMCs) in the formation of senescence-associated medial calcification. Replicative senescence was induced by the extended passages (until passages 11–13) in human primary VSMCs, and cells in early passage ( passage 6) were used as control young cells. VSMC calcification was markedly enhanced in the senescent cells compared with that in the control young cells. We identified that genes highly expressed in osteoblasts, such as alkaline phosphatase (ALP) and type I collagen, were significantly upregulated in the senescent VSMCs, suggesting their osteoblastic transition during the senescence. Knockdown of either ALP or type I collagen significantly reduced the calcification in the senescent VSMCs. Of note, runt-related transcription factor-2 (RUNX-2), a core transcriptional factor that initiates the osteoblastic differentiation, was also upregulated in the senescent VSMCs. Knockdown of RUNX-2 significantly reduced the ALP expression and calcification in the senescent VSMCs, suggesting that RUNX-2 is involved in the senescence-mediated osteoblastic transition. Furthermore, immunohistochemistry of aorta from the klotho−/− aging mouse model demonstrated in vivo emergence of osteoblast-like cells expressing RUNX-2 exclusively in the calcified media. We also found that statin and Rho-kinase inhibitor effectively reduced the VSMC calcification by inhibiting Pi-induced apoptosis and potentially enhancing matrix Gla protein expression in the senescent VSMCs. These findings strongly suggest an important role of senescent VSMCs in the pathophysiology of senescence-associated medial calcification, and the inhibition of osteoblastic transition could be a new therapeutic approach for the prevention of senescence-associated medial calcification.
Impaired function of coronary BKCachannels in metabolic syndrome
Authors: Borbouse Léna , Dick Gregory M. , Asano Shinichi , Bender Shawn B. , Dincer U. Deniz , Payne Gregory A. , Neeb Zachary P. , Bratz Ian N. , Sturek Michael , Tune Johnathan D.
Published: September 2009

The role of large-conductance Ca2+-activated K+(BKCa) channels in regulation of coronary microvascular function is widely appreciated, but molecular and functional changes underlying the deleterious influence of metabolic syndrome (MetS) have not been determined. Male Ossabaw miniature swine consumed for 3–6 mo a normal diet (11% kcal from fat) or an excess-calorie atherogenic diet that induces MetS (45% kcal from fat, 2% cholesterol, 20% kcal from fructose). MetS significantly impaired coronary vasodilation to the BKCaopener NS-1619 in vivo (30–100 μg) and reduced the contribution of these channels to adenosine-induced microvascular vasodilation in vitro (1–100 μM). MetS reduced whole cell penitrem A (1 μM)-sensitive K+current and NS-1619-activated (10 μM) current in isolated coronary vascular smooth muscle cells. MetS increased the concentration of free intracellular Ca2+and augmented coronary vasoconstriction to the L-type Ca2+channel agonist BAY K 8644 (10 pM–10 nM). BKCachannel α and β1protein expression was increased in coronary arteries from MetS swine. Coronary vascular dysfunction in MetS is related to impaired BKCachannel function and is accompanied by significant increases in L-type Ca2+channel-mediated coronary vasoconstriction.
Maturation and the role of PKC-mediated contractility in ovine cerebral arteries
Authors: Goyal Ravi , Mittal Ashwani , Chu Nina , Shi Lijun , Zhang Lubo , Longo Lawrence D.
Published: September 2009

Ca2+-independent pathways such as protein kinase C (PKC), extracellular-regulated kinases 1 and 2 (ERK1/2), and Rho kinase 1 and 2 (ROCK1/2) play important roles in modulating cerebral vascular tone. Because the roles of these kinases vary with maturational age, we tested the hypothesis that PKC differentially regulates the Ca2+-independent pathways and their effects on cerebral arterial contractility with development. We simultaneously examined the responses of arterial tension and intracellular Ca2+concentration and used Western immunoblot analysis to measure ERK1/2, RhoA, 20 kDa regulatory myosin light chain (MLC20), PKC-potentiated inhibitory protein of 17 kDa (CPI-17), and caldesmon. Phorbol 12,13-dibutyrate (PDBu)-mediated PKC activation produced a robust contractile response, which was increased a further 20 to 30% by U-0126 (MEK inhibitor) in cerebral arteries of both age groups. Of interest, in the fetal cerebral arteries, PDBu leads to an increased phosphorylation of ERK2 compared with ERK1, whereas in adult arteries, we observed an increased phosphorylation of ERK1 compared with ERK2. Also, in the present study, RhoA/ROCK played a significant role in the PDBu-mediated contractility of fetal cerebral arteries, whereas in adult cerebral arteries, CPI-17 and caldesmon had a significantly greater role compared with the fetus. PDBu also led to an increased MLC20phosphorylation, a response blunted by the inhibition of myosin light chain kinase only in the fetus. Overall, the present study demonstrates an important maturational shift from RhoA/ROCK-mediated to CPI-17/caldesmon-mediated PKC-induced contractile response in ovine cerebral arteries.
Lack of cardiac fibrosis in a new model of high prorenin hyperaldosteronism
Authors: Peters Jörg , Schlüter Torsten , Riegel Thomas , Peters Barbara S. , Beineke Andreas , Maschke Ulrike , Hosten Norbert , Mullins John J. , Rettig Rainer
Published: September 2009

The aim of the present study was to test the hypothesis that elevation of prorenin in plasma is sufficient to induce cardiac fibrosis. Normotensive cyp1a1 ren-2 transgenic rats with normal plasma prorenin and aldosterone levels were given 0.125% indole-3-carbinol (I3C) orally for a period of 12 wk. Plasma prorenin and aldosterone levels were determined in 4-wk intervals, and cardiac marker enzymes for hypertrophy, fibrosis, and oxidative stress as well as cardiac pathology were investigated. In I3C-treated cyp1a1 ren-2 transgenic rats, plasma prorenin concentrations were >100-fold elevated (≥7.1 ± 2.6 μg ANG I·ml−1·h−1 vs. ≤0.07 ± 0.1; P < 0.001), whereas active renin levels were suppressed (0.09 ± 0.02 vs. 0.2 ± 0.1; P < 0.05). Aldosterone concentrations were elevated three- to fourfold for a period of >4 wk (574 ± 51 vs. 160 ± 68 pg/ml; P < 0.01). After 12 wk of I3C, rats exhibited moderate cardiac hypertrophy (heart weight/body weight 2.5 ± 0.04 vs. 3.1 ± 0.1 mg/g; P < 0.01). There was a slight increase in mRNA contents of endothelin 1 (1.21 ± 0.08 vs. 0.75 ± 0.007; P < 0.001), NADP oxidase-2 (1.03 ± 0.006 vs. 0.76 ± 0.04; P < 0.001), transforming growth factor-β (0.99 ± 0.06 vs. 0.84 ± 0.04; P < 0.05), collagen type I (1.32 ± 0.32 vs. 0.94 ± 0.18; P < 0.05), and intercellular adhesion molecule-1 (1.12 ± 0.12 vs. 0.84 ± 0.08; P < 0.05). These genes are known to be stimulated by the renin-angiotensin system. There were no histological signs of fibrosis in the heart. We found that prorenin and aldosterone alone are not sufficient to induce considerable cardiac fibrosis in the absence of sodium load.
A random cycle length approach for assessment of myocardial contraction in isolated rabbit myocardium
Authors: Varian Kenneth D. , Xu Ying , Torres Carlos A. A. , Monasky Michelle M. , Janssen Paul M. L.
Published: September 2009

It is well known that the strength of cardiac contraction is dependent on the cycle length, evidenced by the force-frequency relationship (FFR) and the existence of postrest potentiation (PRP). Because the contractile strength of the steady-state FFR and force-interval relationship involve instant intrinsic responses to cycle length as well as slower acting components such as posttranslational modification-based mechanisms, it remains unclear how cycle length intrinsically affects cardiac contraction and relaxation. To dissect the impact of cycle length changes from slower acting signaling components associated with persisting changes in cycle length, we developed a novel technique/protocol to study cycle length-dependent effects on cardiac function; twitch contractions of right ventricular rabbit trabeculae at different cycle lengths were randomized around a steady-state frequency. Patterns of cycle lengths that resulted in changes in force and/or relaxation times can now be identified and analyzed. Using this novel protocol, taking under 10 min to complete, we found that the duration of the cycle length before a twitch contraction (“primary” cycle length) positively correlated with force. In sharp contrast, the cycle length one (“secondary”) or two (“tertiary”) beats before the analyzed twitch correlated negatively with force. Using this protocol, we can quantify the intrinsic effect of cycle length on contractile strength while avoiding rundown and lengthiness that are often complications of FFR and PRP assessments. The data show that the history of up to three cycle lengths before a contraction influences myocardial contractility and that primary cycle length affects cardiac twitch dynamics in the opposite direction from secondary/tertiary cycle lengths.
Therapeutic effects of hypercapnia on chronic lung injury and vascular remodeling in neonatal rats
Authors: Masood Azhar , Yi Man , Lau Mandy , Belcastro Rosetta , Shek Samuel , Pan Jingyi , Kantores Crystal , McNamara Patrick J. , Kavanagh Brian P. , Belik Jaques , Jankov Robert P. , Tanswell A. Keith
Published: September 2009

Permissive hypercapnia, achieved using low tidal volume ventilation, has been an effective protective strategy in patients with acute respiratory distress syndrome. To date, no such protective effect has been demonstrated for the chronic neonatal lung injury, bronchopulmonary dysplasia. The objective of our study was to determine whether evolving chronic neonatal lung injury, using a rat model, is resistant to the beneficial effects of hypercapnia or simply requires a less conservative approach to hypercapnia than that applied clinically to date. Neonatal rats inhaled air or 60% O2 for 14 days with or without 5.5% CO2. Lung parenchymal neutrophil and macrophage numbers were significantly increased by hyperoxia alone, which was associated with interstitial thickening and reduced secondary crest formation. The phagocyte influx, interstitial thickening, and impaired alveolar formation were significantly attenuated by concurrent hypercapnia. Hyperoxic pups that received 5.5% CO2 had a significant increase in alveolar number relative to air-exposed pups. Increased tyrosine nitration, a footprint for peroxynitrite-mediated reactions, arteriolar medial wall thickening, and both reduced small peripheral pulmonary vessel number and VEGF and angiopoietin-1 (Ang-1) expression, which were observed with hyperoxia, was attenuated by concurrent hypercapnia. We conclude that evolving chronic neonatal lung injury in a rat model is responsive to the beneficial effects of hypercapnia. Inhaled 5.5% CO2 provided a significant degree of protection against parenchymal and vascular injury in an animal model of chronic neonatal lung injury likely due, at least in part, to its inhibition of a phagocyte influx.
Elastase- and LPS-exposed mice display altered responses to rhinovirus infection
Authors: Sajjan Umadevi , Ganesan Shyamala , Comstock Adam T. , Shim Jee , Wang Qiong , Nagarkar Deepti R. , Zhao Ying , Goldsmith Adam M. , Sonstein Joanne , Linn Marisa J. , Curtis Jeffrey L. , Hershenson Marc B.
Published: September 2009

Viral infection is associated with approximately one-half of acute exacerbations of chronic obstructive pulmonary disease (COPD), which in turn, accelerate disease progression. In this study, we infected mice exposed to a combination of elastase and LPS, a constituent of cigarette smoke and a risk factor for development of COPD, with rhinovirus serotype 1B, and examined animals for viral persistence, airway resistance, lung volume, and cytokine responses. Mice exposed to elastase and LPS once a week for 4 wk showed features of COPD such as airway inflammation and obstruction, goblet cell metaplasia, reduced lung elastance, increased total lung volume, and increased alveolar chord length. In general, mice exposed to elastase or LPS alone showed intermediate effects. Compared with rhinovirus (RV)-infected PBS-exposed mice, RV-infected elastase/LPS-exposed mice showed persistence of viral RNA, airway hyperresponsiveness, increased lung volume, and sustained increases in expression of TNFα, IL-5, IL-13, and muc5AC (up to 14 days postinfection). Furthermore, virus-induced IFNs, interferon response factor-7, and IL-10 were deficient in elastase/LPS-treated mice. Mice exposed to LPS or elastase alone cleared virus similar to PBS-treated control mice. We conclude that limited exposure of mice to elastase/LPS produces a COPD-like condition including increased persistence of RV, likely due to skewing of the immune response towards a Th2 phenotype. Similar mechanisms may be operative in COPD.