bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of DNA Binding Sites of the ComE Response Regulator from Streptococcus mutans
Authors: Hung David C. I. , Downey Jennifer S. , Ayala Eduardo A. , Kreth Jens , Mair Richard , Senadheera Dilani B. , Qi Fengxia , Cvitkovitch Dennis G. , Shi Wenyuan , Goodman Steven D.
Published: May 2011

In
Streptococcus mutans
, both competence and bacteriocin production are controlled by ComC and the ComED two-component signal transduction system. Recent studies of
S. mutans
suggested that purified ComE binds to two 11-bp direct repeats in the
nlmC-comC
promoter region, where ComE activates
nlmC
and represses
comC
. In this work, quantitative binding studies and DNase I footprinting analysis were performed to calculate the equilibrium dissociation constant and further characterize the binding site of ComE. We found that ComE protects sequences inclusive of both direct repeats, has an equilibrium dissociation constant in the nanomolar range, and binds to these two direct repeats cooperatively. Furthermore, similar direct repeats were found upstream of
cslAB
,
comED
,
comX
,
ftf
,
vicRKX
,
gtfD
,
gtfB
,
gtfC
, and
gbpB.
Quantitative binding studies were performed on each of these sequences and showed that only
cslAB
has a similar specificity and high affinity for ComE as that seen with the upstream region of
comC
. A mutational analysis of the binding sequences showed that ComE does not require both repeats to bind DNA with high affinity, suggesting that single site sequences in the genome may be targets for ComE-mediated regulation. Based on the mutational analysis and DNase I footprinting analysis, we propose a consensus ComE binding site, TCBTAAAYSGT.
Characterization of Peptide Chain Length and Constituency Requirements for YejABEF-Mediated Uptake of Microcin C Analogues
Authors: Vondenhoff Gaston H. M. , Blanchaert Bart , Geboers Sophie , Kazakov Teymur , Datsenko Kirill A. , Wanner Barry L. , Rozenski Jef , Severinov Konstantin , Van Aerschot Arthur
Published: May 2011

Microcin C (McC), a natural antibacterial compound consisting of a heptapeptide attached to a modified adenosine, is actively taken up by the YejABEF transporter, after which it is processed by cellular aminopeptidases, releasing the nonhydrolyzable aminoacyl adenylate, an inhibitor of aspartyl-tRNA synthetase. McC analogues with variable length of the peptide moiety were synthesized and evaluated in order to characterize the substrate preferences of the YejABEF transporter. It was shown that a minimal peptide chain length of 6 amino acids and the presence of an N-terminal formyl-methionyl-arginyl sequence are required for transport.
Comparative Genomics of the Dormancy Regulons in Mycobacteria
Authors: Gerasimova Anna , Kazakov Alexey E. , Arkin Adam P. , Dubchak Inna , Gelfand Mikhail S.
Published: May 2011

In response to stresses,
Mycobacterium
cells become dormant. This process is regulated by the DosR transcription factor. In
Mycobacterium tuberculosis
, the dormancy regulon is well characterized and contains the
dosR
gene itself and
dosS
and
dosT
genes encoding DosR kinases, nitroreductases (
acg
;
Rv3131
), diacylglycerol acyltransferase (DGAT) (
Rv3130c
), and many universal stress proteins (USPs). In this study, we apply comparative genomic analysis to characterize the DosR regulons in nine
Mycobacterium
genomes,
Rhodococcus
sp. RHA1,
Nocardia farcinica
, and
Saccharopolyspora erythraea.
The regulons are highly labile, containing eight core gene groups (regulators, kinases, USPs, DGATs, nitroreductases, ferredoxins, heat shock proteins, and the orthologs of the predicted kinase [Rv2004c] from
M. tuberculosis
) and 10 additional genes with more restricted taxonomic distribution that are mostly involved in anaerobic respiration. The largest regulon is observed in
M. marinum
and the smallest in
M. abscessus
. Analysis of large gene families encoding USPs, nitroreductases, and DGATs demonstrates a mosaic distribution of regulated and nonregulated members, suggesting frequent acquisition and loss of DosR-binding sites.
Deciphering the Electron Transport Pathway for Graphene Oxide Reduction by Shewanella oneidensis MR-1
Authors: Jiao Yongqin , Qian Fang , Li Yat , Wang Gongming , Saltikov Chad W. , Gralnick Jeffrey A.
Published: May 2011

We determined that graphene oxide reduction byShewanella oneidensisMR-1 requires the Mtr respiratory pathway by analyzing a range of mutants lacking these proteins. Electron shuttling compounds increased the graphene oxide reduction rate 3- to 5-fold. These results may help facilitate the use of bacteria for large-scale graphene production.
Broad-Spectrum Biofilm Inhibition by Kingella kingae Exopolysaccharide
Authors: Bendaoud Meriem , Vinogradov Evgeny , Balashova Nataliya V. , Kadouri Daniel E. , Kachlany Scott C. , Kaplan Jeffrey B.
Published: May 2011

Cell-free extracts prepared from
Kingella kingae
colony biofilms were found to inhibit biofilm formation by
Aggregatibacter actinomycetemcomitans
,
Klebsiella pneumoniae
,
Staphylococcus aureus
,
Staphylococcus epidermidis
,
Candida albicans
, and
K. kingae
. The extracts evidently inhibited biofilm formation by modifying the physicochemical properties of the cell surface, the biofilm matrix, and the substrate. Chemical and biochemical analyses indicated that the biofilm inhibition activity in the
K. kingae
extract was due to polysaccharide. Structural analyses showed that the extract contained two major polysaccharides. One was a linear polysaccharide with the structure →6)-α-
d
-GlcNAc
p
-(1→5)-β-
d
-OclA
p
-(2→, which was identical to a capsular polysaccharide produced by
Actinobacillus pleuropneumoniae
serotype 5. The second was a novel linear polysaccharide, designated PAM galactan, with the structure →3)-β-
d
-Gal
f
-(1→6)-β-
d
-Gal
f
-(1→. Purified PAM galactan exhibited broad-spectrum biofilm inhibition activity. A cluster of three
K. kingae
genes encoding UDP-galactopyranose mutase (
ugm
) and two putative galactofuranosyl transferases was sufficient for the synthesis of PAM galactan in
Escherichia coli
. PAM galactan is one of a growing number of bacterial polysaccharides that exhibit antibiofilm activity. The biological roles and potential technological applications of these molecules remain unknown.
Phenazine-1-Carboxylic Acid Promotes Bacterial Biofilm Development via Ferrous Iron Acquisition
Authors: Wang Yun , Wilks Jessica C. , Danhorn Thomas , Ramos Itzel , Croal Laura , Newman Dianne K.
Published: May 2011

The opportunistic pathogen
Pseudomonas aeruginosa
forms biofilms, which render it more resistant to antimicrobial agents. Levels of iron in excess of what is required for planktonic growth have been shown to promote biofilm formation, and therapies that interfere with ferric iron [Fe(III)] uptake combined with antibiotics may help treat
P. aeruginosa
infections. However, use of these therapies presumes that iron is in the Fe(III) state in the context of infection. Here we report the ability of phenazine-1-carboxylic acid (PCA), a common phenazine made by all phenazine-producing pseudomonads, to help
P. aeruginosa
alleviate Fe(III) limitation by reducing Fe(III) to ferrous iron [Fe(II)]. In the presence of PCA, a
P. aeruginosa
mutant lacking the ability to produce the siderophores pyoverdine and pyochelin can still develop into a biofilm. As has been previously reported (P. K. Singh, M. R. Parsek, E. P. Greenberg, and M. J. Welsh, Nature 417:552-555, 2002), biofilm formation by the wild type is blocked by subinhibitory concentrations of the Fe(III)-binding innate-immunity protein conalbumin, but here we show that this blockage can be rescued by PCA. FeoB, an Fe(II) uptake protein, is required for PCA to enable this rescue. Unlike PCA, the phenazine pyocyanin (PYO) can facilitate biofilm formation via an iron-independent pathway. While siderophore-mediated Fe(III) uptake is undoubtedly important at early stages of infection, these results suggest that at later stages of infection, PCA present in infected tissues may shift the redox equilibrium between Fe(III) and Fe(II), thereby making iron more bioavailable.
Structure of Burkholderia cepacia UDP-Glucose Dehydrogenase (UGD) BceC and Role of Tyr10 in Final Hydrolysis of UGD Thioester Intermediate
Authors: Rocha Joana , Popescu Alma O. , Borges Patrícia , Mil-Homens Dalila , Moreira Leonilde M. , Sá-Correia Isabel , Fialho Arsénio M. , Frazão Carlos
Published: May 2011

Members of the
Burkholderia cepacia
complex (BCC) are serious respiratory pathogens in immunocompromised individuals and in patients with cystic fibrosis (CF). They are exceptionally resistant to many antimicrobial agents and have the capacity to spread between patients, leading to a decline in lung function and necrotizing pneumonia. BCC members often express a mucoid phenotype associated with the secretion of the exopolysaccharide (EPS) cepacian. There is much evidence supporting the fact that cepacian is a major virulence factor of BCC. UDP-glucose dehydrogenase (UGD) is responsible for the NAD-dependent 2-fold oxidation of UDP-glucose (UDP-Glc) to UDP-glucuronic acid (UDP-GlcA), which is a key step in cepacian biosynthesis. Here, we report the structure of BceC, determined at 1.75-Å resolution. Mutagenic studies were performed on the active sites of UGDs, and together with the crystallographic structures, they elucidate the molecular mechanism of this family of sugar nucleotide-modifying enzymes. Superposition with the structures of human and other bacterial UGDs showed an active site with high structural homology. This family contains a strictly conserved tyrosine residue (Y10 in BceC; shown in italics) within the glycine-rich motif (GXG
Y
XG) of its N-terminal Rossmann-like domain. We constructed several BceC Y10 mutants, revealing only residual dehydrogenase activity and thus highlighting the importance of this conserved residue in the catalytic activity of BceC. Based on the literature of the UGD/GMD nucleotide sugar 6-dehydrogenase family and the kinetic and structural data we obtained for BceC, we determined Y10 as a key catalytic residue in a UGD rate-determining step, the final hydrolysis of the enzymatic thioester intermediate.
Characterization of a Novel Heat Shock Protein (Hsp22.5) Involved in the Pathogenesis of Mycobacterium tuberculosis
Authors: Abomoelak Bassam , Marcus Sarah A. , Ward Sarah K. , Karakousis Petros C. , Steinberg Howard , Talaat Adel M.
Published: May 2011

Tuberculosis is a worldwide health problem, given that one-third of the world's population is currently infected with
Mycobacterium tuberculosis
. Understanding the regulation of virulence on the molecular level will provide a better understanding of how
M. tuberculosis
can establish chronic infection. Using
in vivo
microarray analysis (IVMA), we previously identified a group of genes that are activated in BALB/c mouse lungs compared to
in vitro
cultures, including the
rv0990c
gene. Our analysis indicated that this gene is a member of the heat shock regulon and was activated under other stress conditions, including survival in macrophages or during the late phase of chronic tuberculosis in the murine lungs. Deletion of
rv0990c
from the genome of
M. tuberculosis
strain H37Rv affected the transcriptional profiles of many genes (
n
= 382) and operons involved in mycobacterial survival, including the dormancy regulon, ATP synthesis, respiration, protein synthesis, and lipid metabolism. Comparison of the proteomes of the mutant to those of the wild-type strain further confirmed the differential expression of 15 proteins, especially those involved in the heat shock response (e.g., DnaK and GrpE). Finally, the
rv0990c
mutant strain showed survival equivalent to that of the isogenic wild-type strain during active tuberculosis in guinea pigs, despite showing significant attenuation in BALB/c mice during the chronic phase of the disease. Overall, we suggest that
rv0990c
encodes a heat shock protein that plays an important role in mycobacterial virulence. Hence, we renamed
rv0990c
heat shock protein 22.5 (
hsp22.5
), reflecting its molecular mass.
S
-Adenosylmethionine-Binding Properties of a Bacterial Phospholipid
N
-Methyltransferase
Authors: Aktas Meriyem , Gleichenhagen Jan , Stoll Raphael , Narberhaus Franz
Published: May 2011

The presence of the membrane lipid phosphatidylcholine (PC) in the bacterial membrane is critically important for many host-microbe interactions. The phospholipid
N
-methyltransferase PmtA from the plant pathogen
Agrobacterium tumefaciens
catalyzes the formation of PC by a three-step methylation of phosphatidylethanolamine via monomethylphosphatidylethanolamine and dimethylphosphatidylethanolamine. The methyl group is provided by
S
-adenosylmethionine (SAM), which is converted to
S
-adenosylhomocysteine (SAH) during transmethylation. Despite the biological importance of bacterial phospholipid
N
-methyltransferases, little is known about amino acids critical for binding to SAM or phospholipids and catalysis. Alanine substitutions in the predicted SAM-binding residues E58, G60, G62, and E84 in
A. tumefaciens
PmtA dramatically reduced SAM-binding and enzyme activity. Homology modeling of PmtA satisfactorily explained the mutational results. The enzyme is predicted to exhibit a consensus topology of the SAM-binding fold consistent with cofactor interaction as seen with most structurally characterized SAM-methyltransferases. Nuclear magnetic resonance (NMR) titration experiments and
14
C-SAM-binding studies revealed binding constants for SAM and SAH in the low micromolar range. Our study provides first insights into structural features and SAM binding of a bacterial phospholipid
N
-methyltransferase.
Identification of Ten Anabaena sp. Genes That under Aerobic Conditions Are Required for Growth on Dinitrogen but Not for Growth on Fixed Nitrogen
Authors: Lechno-Yossef Sigal , Fan Qing , Wojciuch Elizabeth , Wolk C. Peter
Published: May 2011

Heterocysts are specialized cells required for aerobic fixation of dinitrogen by certain filamentous cyanobacteria. Numerous genes involved in the differentiation and function of heterocysts in
Anabaena
sp. strain PCC 7120 have been identified by mutagenizing and screening for mutants that require fixed nitrogen for growth in the presence of oxygen. We have verified that 10
Anabaena
sp. genes,
all1338
,
all1591
,
alr1728
,
all3278
,
all3520
,
all3582
,
all3850
,
all4019
,
alr4311
, and
all4388
, identified initially by transposon mutagenesis, are such genes by complementing or reconstructing the original mutation and by determining whether the mutant phenotype might be due to a polar effect of the transposon. Elucidation of the roles of these genes should enhance understanding of heterocyst biology.
Redesigning Introductory Biology: A Proposal
Authors: Gregory Eileen , Lending Craig , Orenstein Amanda N. , Ellis Jane P.
Published: May 2011

With the increasing complexity and expansion of the biological sciences, there has been a corresponding increase in content in the first-year introductory biology course sequence for majors. In general this has resulted in courses that introduce students to large amounts of material and leave little time for practicing investigative science or skill development. Based on our analysis of data compiled from 742 biology faculty at a variety of institutions across the United States, we verified that there is strong agreement on the content appropriate for introductory biology courses for majors. Therefore, we propose that faculty teaching these courses focus primarily on the topics identified in this study, and redesign their courses to incorporate active learning strategies that emphasize the investigative nature of biology and provide opportunities for skill development.
Non-steroidal anti-inflammatory drug (NSAID) related inhibition of aldosterone glucuronidation and arterial dysfunction in patients with rheumatoid arthritis: a cross-sectional clinical study
Authors: Crilly Michael A , Mangoni Arduino A
Published: May 2011

Objective

Patients with rheumatoid arthritis (RA) are at increased risk of cardiovascular (CV) disease and are also commonly prescribed non-selective non-steroidal anti-inflammatory drugs (ns-NSAIDs). New in vitro evidence suggests that this increased CV risk may be mediated through aldosterone glucuronidation inhibition (AGI), which differs between NSAIDs (diclofenac>naproxen>indomethacin>ibuprofen). Our aim was to explore the association between ns-NSAID-related AGI and arterial dysfunction.

Methods

The extent (augmentation index, AIX%) and timing (reflected wave transit time, RWT, ms) of aortic wave reflection (measured using radial applanation pulse wave analysis, PWA, SphygmoCor device) were assessed on a single occasion in 114 consecutive RA patients without overt CV disease aged 40–65 years. A higher AIX% and lower RWT indicate arterial dysfunction. Assessment included a fasting blood sample, patient questionnaire and medical record review. Multivariate analysis was used to adjust for age, sex, mean blood pressure, smoking, cumulative erythrocyte sedimentation rate (ESR-years) and Stanford disability score.

Results

We identified 60 patients taking ns-NSAIDs and 25 non-users. Using a ns-NSAID with the highest AGI was associated with a higher AIX% (and lower RWT) versus treatment with a ns-NSAID with the lowest AGI (diclofenac AIX% 32.3, RWT 132.7 ms vs ibuprofen AIX% 23.8, RWT 150.9 ms): adjusted mean differences AIX% 6.5 (95% CI 1.0 to 11.9; p=0.02); RWT −14.2 ms (95% CI −22.2 to −6.3; p=0.001). Indomethacin demonstrated an intermediate level of arterial dysfunction. In relation to arterial dysfunction, both indomethacin and naproxen were more similar to diclofenac than to ibuprofen.

Conclusions

ns-NSAID-related AGI is associated with arterial dysfunction in patients with RA. These findings provide a potentially novel insight into the CV toxicity of commonly used ns-NSAIDs. However, the findings are limited by the small number of patients involved and require further replication in a much larger study.
Evaluation of adjunct immunohistochemistry on reporting patterns of non-small cell lung carcinoma diagnosed histologically in a regional pathology centre
Authors: McLean E C , Monaghan H , Salter D M , Wallace W A
Published: May 2011

Morphological sub-classification of non-small cell carcinoma in small biopsy specimens presents difficulties for pathologists and recent advances in chemotherapy have resulted in increased pressure to more robustly differentiate between squamous carcinoma and adenocarcinoma. The results of audits examining classification of non-small cell lung carcinoma by pathologists working in a specialist team within a regional centre and the effect of introducing adjunct immunohistochemistry into the reporting pathway are presented. It is concluded that the use of a limited immunohistochemical panel substantially reduces the number of cases when a specific cell type cannot be identified or ‘favoured’ (34% to 6%) and that the classification obtained correlates well with that found in subsequent resection specimens. In addition the introduction of immunohistochemistry substantially reduces the variability in reporting practice between pathologists.
The effectiveness of two active interventions compared to self-care advice in employees with non-acute low back symptoms: a randomised, controlled trial with a 4-year follow-up in the occupational health setting
Authors: Rantonen J , Luoto S , Vehtari A , Hupli M , Karppinen J , Malmivaara A , Taimela S
Published: May 2011

Objective

Evaluate the effectiveness of two active interventions, aimed at secondary prevention of low back pain (LBP), in occupational health.

Methods

We performed a survey of LBP (n=2480; response rate 71%) and randomized 143 employees (66% males, 45 years) with LBP over 34 mm on VAS into Rehabilitation (n=43), Exercise (n=43) or self-care (n=40) groups. Primary outcomes were LBP, physical impairment (PI) and health-related quality of life (HRQoL) for two years and sickness absence (SA) days during four years (LBP specific, total).

Results

Compared to self-care, exercise reduced LBP at 12 months (mean difference (MD) −12 mm; 95% CI −21 to −2) and improved HRQoL at 12 and 24 months (0.03; 0.00 to 0.05), but did not reduce PI. The MDs of SA days in four years were −17 (−70 to 35, total) and −15 (−47 to 13, LBP specific). Exercise reduced the probability of LBP specific SA during the third and fourth year. Compared to self-care, Rehabilitation reduced LBP at 3 months (−10 mm; −19 to −1) and 6 months (−10 mm; −20 to − 1), but was not effective in HRQoL or PI. The MDs of SA days in four years were −41 (−93 to 8; total) and 5 (−30 to 47; LBP specific). Rehabilitation reduced the probability of total SA during first and second year and amount of total SA days in the fourth year.

Conclusions

Among employees with relatively mild LBP, both interventions reduced pain, but the effects on SA and PI were minor. Exercise improved HRQoL. The effect sizes were rather small.

Trial registration

Number ClinicalTrials.govNCT00908102.
Association between cleaning-related chemicals and work-related asthma and asthma symptoms among healthcare professionals
Authors: Arif Ahmed A , Delclos George L
Published: May 2011

Objectives

Work-related asthma (WRA) is an important public health problem affecting one quarter of adults with asthma. Although cleaning substances are routinely used in hospitals, few studies have addressed their potential adverse respiratory health effects on healthcare professionals (HCPs). This study attempts to identify relationship between work-related exposure to cleaning-related chemicals and development of WRA among HCPs.

Methods

Of 5600 HCPs surveyed, 3650 responded to a validated questionnaire about their occupation, asthma diagnosis, variability of asthma symptoms at and away from work, and exposure to individual cleaning substances. Workplace asthma was defined as a categorical variable with four mutually exclusive categories: work-related asthma symptoms (WRAS), work-exacerbated asthma (WEA), occupational asthma (OA) and none. Multivariable logistic regression analysis was used to evaluate the association between self-reported use of cleaning substances and asthma outcomes among HCPs.

Results

Prevalences of WRAS, WEA and OA were 3.3%, 1.1% and 0.8%, respectively. The prevalence estimates were generally higher among female than male HCPs. The odds of WRAS and WEA increased in a dose-dependent manner for exposure in the longest job to cleaning agents and disinfectants/sterilants, respectively. For exposure in any job, the odds of WRAS were significantly elevated for both factor 1 (bleach, cleaners/abrasives, toilet cleaners, detergents and ammonia) and factor 2 (glutaraldehyde/ortho-phtaldehyde, chloramines and ethylene oxide). Significantly elevated odds of WEA were observed for exposure to bleach, factor 2 and formalin/formaldehyde. Exposure to chloramines was significantly associated with an almost fivefold elevated odds of OA.

Conclusions

HCPs are at risk of developing WRA from exposure to cleaning substances.
Reduction in hospital admissions for acute coronary syndrome after the successful implementation of 100% smoke-free legislation in Argentina: a comparison with partial smoking restrictions
Authors: Ferrante D , Linetzky B , Virgolini M , Schoj V , Apelberg B
Published: May 2011

Background

Several studies have shown a decrease in acute coronary syndrome (ACS) admissions after the implementation of 100% smoke-free legislation. However, no studies have been conducted in developing countries.

Methods

We conducted a time series analysis of ACS hospital admissions in Santa Fe province and Buenos Aires city, Argentina. In 2006, Santa Fe implemented a 100% smoke-free law and Buenos Aires implemented a partial law with designated smoking areas and exceptions. Age-standardised ACS admissions rates were compared before and after the implementation of the laws in each district. Smoking prevalence, compliance with legislation and exposure to secondhand smoke (SHS) was also assessed in both districts.

Results

In Santa Fe an immediate decrease in ACS admissions was observed after implementation (−2.5 admissions per 100 000, p=0.03; 13% reduction), compared with no change in Buenos Aires city (rate ratio Santa Fe vs Buenos Aires: 0.74, 95% CI 0.63 to 0.86, p≤0.001). In Santa Fe, the immediate effect was followed by a persistent decrease in admissions due to ACS (−0.26 admissions per 100 000 per month). Smoking prevalence did not change significantly in either district during the same period. In both districts, there was a reduction in self-reported SHS exposure, with a trend towards lower exposure in Santa Fe province. No other comprehensive tobacco control interventions were implemented during the study period.

Conclusions

A 100% smoke-free law was more effective than a partial restriction law in reducing ACS admissions. An immediate effect was followed by a sustained decrease in ACS admissions. Smoke-free initiatives can be also effective in decreasing acute coronary events in developing countries.
LINEAR GENERALIZED SYNCHRONIZATION OF SPATIAL JULIA SETS
Authors: LIU PING , LIU CHANGAN
Published: May 2011

In this paper, the generalized synchronization of spatial Julia sets is investigated by applying linear coupling. We achieve the generalized synchronization of two different spatial Julia sets and also obtain the stable domain of the coupling strength based on the stable domains given of the spatial Julia sets. The relationship between the complex fixed plane and the synchronization of the spatial Julia sets is also analyzed and shows that the anticipative objective is accomplished. Finally, simulations are presented to demonstrate the effectiveness and feasibility of linear coupling.
Inducible nitric oxide synthase provides protection against injury-induced thrombosis in female mice
Authors: Upmacis Rita K. , Shen Hao , Benguigui Lea Esther S. , Lamon Brian D. , Deeb Ruba S. , Hajjar Katherine A. , Hajjar David P.
Published: May 2011

Nitric oxide (NO) is an important vasoactive molecule produced by three NO synthase (NOS) enzymes: neuronal (nNOS), inducible (iNOS), and endothelial NOS (eNOS). While eNOS contributes to blood vessel dilation that protects against the development of hypertension, iNOS has been primarily implicated as a disease-promoting isoform during atherogenesis. Despite this, iNOS may play a physiological role via the modulation of cyclooxygenase and thromboregulatory eicosanoid production. Herein, we examined the role of iNOS in a murine model of thrombosis. Blood flow was measured in carotid arteries of male and female wild-type (WT) and iNOS-deficient mice following ferric chloride-induced thrombosis. Female WT mice were more resistant to thrombotic occlusion than male counterparts but became more susceptible upon iNOS deletion. In contrast, male mice (with and without iNOS deletion) were equally susceptible to thrombosis. Deletion of iNOS was not associated with a change in the balance of thromboxane A2(TxA2) or antithrombotic prostacyclin (PGI2). Compared with male counterparts, female WT mice exhibited increased urinary nitrite and nitrate levels and enhanced ex vivo induction of iNOS in hearts and aortas. Our findings suggest that iNOS-derived NO in female WT mice may attenuate the effects of vascular injury. Thus, although iNOS is detrimental during atherogenesis, physiological iNOS levels may contribute to providing protection against thrombotic occlusion, a phenomenon that may be enhanced in female mice.
SPARC mediates early extracellular matrix remodeling following myocardial infarction
Authors: McCurdy Sarah M. , Dai Qiuxia , Zhang Jianhua , Zamilpa Rogelio , Ramirez Trevi A. , Dayah Tariq , Nguyen Nguyen , Jin Yu-Fang , Bradshaw Amy D. , Lindsey Merry L.
Published: May 2011

Secreted protein, acidic, and rich in cysteine (SPARC) is a matricellular protein that functions in the extracellular processing of newly synthesized collagen. Collagen deposition to form a scar is a key event following a myocardial infarction (MI). Because the roles of SPARC in the early post-MI setting have not been defined, we examined age-matched wild-type (WT; n=22) and SPARC-deficient (null; n=25) mice at day 3 post-MI. Day 0 WT ( n=28) and null ( n=20) mice served as controls. Infarct size was 52 ± 2% for WT and 47 ± 2% for SPARC null ( P=NS), indicating that the MI injury was comparable in the two groups. By echocardiography, WT mice increased end-diastolic volumes from 45 ± 2 to 83 ± 5 μl ( P < 0.05). SPARC null mice also increased end-diastolic volumes but to a lesser extent than WT (39 ± 3 to 63 ± 5 μl; P < 0.05 vs. day 0 controls and vs. WT day 3 MI). Ejection fraction fell post-MI in WT mice from 57 ± 2 to 19 ± 1%. The decrease in ejection fraction was attenuated in the absence of SPARC (65 ± 2 to 28 ± 2%). Fibroblasts isolated from SPARC null left ventricle (LV) showed differences in the expression of 22 genes encoding extracellular matrix and adhesion molecule genes, including fibronectin, connective tissue growth factor (CTGF; CCN2), matrix metalloproteinase-3 (MMP-3), and tissue inhibitor of metalloproteinase-2 (TIMP-2). The change in fibroblast gene expression levels was mirrored in tissue protein extracts for fibronectin, CTGF, and MMP-3 but not TIMP-2. Combined, the results of this study indicate that SPARC deletion preserves LV function at day 3 post-MI but may be detrimental for the long-term response due to impaired fibroblast activation.
Vascular oxidative stress in aging: a homeostatic failure due to dysregulation of NRF2-mediated antioxidant response
Authors: Ungvari Zoltan , Bailey-Downs Lora , Sosnowska Danuta , Gautam Tripti , Koncz Peter , Losonczy Gyorgy , Ballabh Praveen , de Cabo Rafael , Sonntag William E. , Csiszar Anna
Published: May 2011

There is strong evidence showing that aging is associated with vascular oxidative stress, which has been causally linked to the development of cardiovascular diseases. NF-E2-related factor-2 (Nrf2) is a transcription factor, which is activated by reactive oxygen species in the vasculature of young animals leading to the upregulation of various antioxidant genes. The present study was designed to elucidate age-related changes in the homeostatic role of Nrf2-driven free radical detoxification mechanisms in the vasculature. We found that in the aorta of Fischer 344 × Brown Norway rats, aging results in a progressive increase in O2·−production, and downregulates protein and mRNA expression of Nrf2, which is associated with a decreased nuclear Nrf2 activity and a decrease in the Nrf2 target genes NAD(P)H:quinone oxidoreductase 1, γ-glutamylcysteine synthetase, and heme oxygenase-1. There was an inverse relationship between vascular expression of Nrf2 target genes and age-related increases in the expression of the NF-κB target genes ICAM-1 and IL-6, which was significant by regression analysis. In cultured aorta segments of young (3 mo old) rats treatment with H2O2and high glucose significantly increases nuclear translocation of Nrf2 and upregulates the expression of Nrf2 target genes. In contrast, in cultured aorta segments of aged (24 mo old) rats, the induction of Nrf2-dependent responses by H2O2and high glucose are blunted. High glucose-induced vascular oxidative stress was more severe in aortas of aged rats, as shown by the significantly increased H2O2production in these vessels, compared with responses obtained in aortas from young rats. Moreover, we found that aging progressively increases vascular sensitivity to the proapoptotic effects of H2O2and high glucose treatments. Taken together, aging is associated with Nrf2 dysfunction in the vasculature, which likely exacerbates age-related cellular oxidative stress and increases sensitivity of aged vessels to oxidative stress-induced cellular damage.
Working towards Usable Forms on the Worldwide Web: Optimizing Multiple Selection Interface Elements
Authors: Bargas-Avila Javier A. , Brenzikofer Olivia , Tuch Alexandre N. , Roth Sandra P. , Opwis Klaus
Published: May 2011

If an interactive form in the worldwide web requires users to select multiple answers from a given list, this can be implemented in several ways. This paper discusses an empirical study with participants, where two interface elements for choosing multiple answers (checkboxes and list boxes) were compared. Results showed that participants chose the same amount of options in both conditions but were faster and more satisfied using checkboxes. The time differences disappeared after several trials, revealing a learning effect for the list box element. As a conclusion, it can be recommended that website developers and online researchers should use checkboxes instead of list boxes for their online forms and questionnaires to enhance usability and user satisfaction—at least for a smaller number of options.
CD8+ T Cells Regulate Bone Tumor Burden Independent of Osteoclast Resorption
Authors: Zhang Kaihua , Kim Seokho , Cremasco Viviana , Hirbe Angela C. , Novack Deborah V. , Weilbaecher Katherine , Faccio Roberta
Published: May 2011

Blockade of osteoclast (OC) activity efficiently decreases tumor burden as well as associated bone erosion in immune-compromised animals bearing human osteolytic cancers. In this study, we showed that modulation of antitumor T-cell responses alters tumor growth in bone, regardless of OC status, by using genetic and pharmacologic models. PLCγ2−/− mice, with dysfunctional OCs and impaired dendritic cell (DC)–mediated T-cell activation, had increased bone tumor burden despite protection from bone loss. In contrast, Lyn−/− mice, with more numerous OCs and a hyperactive myeloid population leading to increased T-cell responses, had reduced tumor growth in bone despite enhanced osteolysis. The unexpected tumor/bone phenotype observed in PLCγ2−/− and Lyn−/− mice was transplantable, suggesting the involvement of an immune component. Consistent with this hypothesis, T-cell activation diminished skeletal metastasis whereas T-cell depletion enhanced it, even in the presence of zoledronic acid, a potent antiresorptive agent. Importantly, injection of antigen-specific wild-type cytotoxic CD8+ T cells in PLCγ2−/− mice or CD8+ T-cell depletion in Lyn−/− mice normalized tumor growth in bone. Our findings show the important contribution of CD8+ T cells in the regulation of bone metastases regardless of OC status, thus including T cells as critical regulators of tumor growth in bone. Cancer Res; 71(14); 4799–808. ©2011 AACR.
Human Tumor Cells Killed by Anthracyclines Induce a Tumor-Specific Immune Response
Authors: Fucikova Jitka , Kralikova Petra , Fialova Anna , Brtnicky Tomas , Rob Lukas , Bartunkova Jirina , Špíšek Radek
Published: May 2011

Immunogenic cell death is characterized by the early surface exposure of chaperones including calreticulin and HSPs, which affect dendritic cell (DC) maturation and the uptake and presentation of tumor antigens. It has also been shown that it is characterized by the late release of high mobility group box 1 (HMGB1), which acts through Toll-like receptor 4 (TLR4) and augments the presentation of antigens from dying tumor cells to DCs. Most of the data on immunogenic tumor cell death were obtained using mouse models. In this study, we investigated the capacity of clinically used chemotherapeutics to induce immunogenic cell death in human tumor cell lines and primary tumor cells. We found that only anthracyclines induced a rapid translocation of calreticulin, HSP70, and HSP90 to the cell surface and the release of HMGB1 12 hours after the treatment. The interaction of immature DCs with immunogenic tumor cells led to an increased tumor cell uptake and induces moderate phenotypic maturation of DCs. Killed tumor cell–loaded DCs efficiently stimulated tumor-specific IFN-γ–producing T cells. DCs pulsed with killed immunogenic tumor cells also induced significantly lower numbers of regulatory T cells than those pulsed with nonimmunogenic tumor cells. These data indicate that human prostate cancer, ovarian cancer, and acute lymphoblastic leukemia cells share the key features of immunogenic cell death with mice tumor cells. These data also identify anthracyclines as anticancer drugs capable of inducing immunogenic cell death in sensitive human tumor cells. Cancer Res; 71(14); 4821–33. ©2011 AACR.
Relationship Between Supranormal Oxygen Tension and Outcome After Resuscitation From Cardiac Arrest
Authors: Kilgannon J. Hope , Jones Alan E. , Parrillo Joseph E. , Dellinger R. Phillip , Milcarek Barry , Hunter Krystal , Shapiro Nathan I. , Trzeciak Stephen
Published: May 2011

Background—

Laboratory and recent clinical data suggest that hyperoxemia after resuscitation from cardiac arrest is harmful; however, it remains unclear if the risk of adverse outcome is a threshold effect at a specific supranormal oxygen tension, or is a dose-dependent association. We aimed to define the relationship between supranormal oxygen tension and outcome in postresuscitation patients.

Methods and Results—

This was a multicenter cohort study using the Project IMPACT database (intensive care units at 120 US hospitals). Inclusion criteria were age >17 years, nontrauma, cardiopulmonary resuscitation preceding intensive care unit arrival, and postresuscitation arterial blood gas obtained. We excluded patients with hypoxia or severe oxygenation impairment. We defined the exposure by the highest partial pressure of arterial oxygen (PaO
2
) over the first 24 hours in the ICU. The primary outcome measure was in-hospital mortality. We tested the association between PaO
2
(continuous variable) and mortality using multivariable logistic regression adjusted for patient-oriented covariates and potential hospital effects. Of 4459 patients, 54% died. The median postresuscitation PaO
2
was 231 (interquartile range 149 to 349) mm Hg. Over ascending ranges of oxygen tension, we found significant linear trends of increasing in-hospital mortality and decreasing survival as functionally independent. On multivariable analysis, a 100 mm Hg increase in PaO
2
was associated with a 24% increase in mortality risk (odds ratio 1.24 [95% confidence interval 1.18 to 1.31]. We observed no evidence supporting a single threshold for harm from supranormal oxygen tension.

Conclusion—

In this large sample of postresuscitation patients, we found a dose-dependent association between supranormal oxygen tension and risk of in-hospital death.
Relationship Between Plasma Inflammatory Markers and Platelet Aggregation in Patients With Clopidogrel Resistance After Angioplasty
Authors: Ge Hailong , Zhou Yujie , Liu Xiaoli , Nie Xiaomin , Wang Zhijian , Guo Yonghe , Chen Wangjun , Yang Qing
Published: May 2011

We evaluated the relationship between plasma inflammation markers and clopidogrel resistance in patients after stent implantation. The plasma levels of C-reactive protein (CRP), P-selectin, platelet soluble CD40 ligand (sCD40L), interleukin 6 (IL-6) and platelet aggregation were measured in 352 patients undergoing percutaneous coronary intervention (PCI) at baseline and after 6 months. The plasma levels of CRP, P-selectin, sCD40L, IL-6 was higher in 65 (18.5%) patients with clopidogrel resistance than in those with normal responsiveness at 6 months after PCI. There was a significant positive correlation between soluble CD40L levels and platelet aggregation ( r = .28, P < .05). Diabetes (DM) and sCD40L level were independent predictors for unresponsiveness after stent implantation according to stepwise multivariate analyses. The hazard ratio (HR) for sCD40L level was 3.02 (95% CI = 1.28 to 3.25; P = .036) and for DM 2.53 (95% CI = 1.28 to 6.55, P = .03). We conclude that sCD40L and DM may influence clopidogrel resistance.
The Changes in Plasma Retinol-Binding Protein 4 Levels are Associated With Those of the Apolipoprotein B-Containing Lipoproteins During Dietary and Drug Treatment
Authors: Christou Georgios A. , Tellis Constantinos C. , Elisaf Moses S. , Tselepis Alexandros D. , Kiortsis Dimitrios N.
Published: May 2011

We investigated the association between retinol-binding protein 4 (RBP4) and apolipoprotein B (ApoB)-containing lipoproteins. Obese or overweight, hypertriglyceridemic patients underwent the following interventions for 3 months: (1) Diet (n = 20), (2) Diet + fenofibrate (n = 18), (3) Diet + rimonabant (n = 8). Circulating RBP4 decreased during dietary treatment. The percentage change in RBP4 was positively correlated with the percentage changes in very-low density lipoprotein cholesterol ( r = .570, P = .02), low-density lipoprotein cholesterol ([LDL-C]; r = .605, P = .01), ApoB ( r = .705, P = .007), and small dense LDL-C ([sdLDL-C]; r = .872, P < .001). The percentage change in RBP4 was the best predictor of the percentage changes in sdLDL-C and ApoB. Rimonabant treatment reduced RBP4, whereas fenofibrate increased RBP4 during the first month of therapy followed by a subsequent decrease. In conclusion, RBP4 may significantly influence the metabolic pathways responsible for changes in ApoB lipoprotein subspecies, thus RBP4 may be associated with cardiovascular disease risk.
Adiponectin and sE-selectin Concentrations in Relation to Inflammation in Obese Type 2 Diabetic Patients With Coronary Heart Disease
Authors: El-Mesallamy Hala O. , Hamdy Nadia M. , Salman Tarek M. , Ibrahim Sherine M.
Published: May 2011

Adipose tissue can release proinflammatory mediators, namely C-reactive protein (CRP), interleukin 1β (IL-1β), and monocyte chemotactic protein 1 (MCP-1), contributing to vascular injury and insulin resistance (IR). Other mediators namely, adiponectin and nitric oxide (NO) are protective. We enrolled type 2 diabetes mellitus (T2DM) obese male patients without coronary heart disease ([CHD] group II, n = 25) and T2DM obese patients with CHD (group III, n = 25). They were compared with 20 age- and body mass index (BMI)-matched nondiabetic control males (group I). Fasting blood glucose (FBG), glycated hemoglobin (HbA1c%), lipids, insulin, malondialdehyde ([MDA]; lipid peroxidation product), NO, high-sensitivity CRP (hsCRP), IL-1β, MCP-1, adiponectin as well as sE-selectin concentration were significantly different in patients with T2DM and CHD compared with patients without CHD and nondiabetic controls ( P = .01). There was a significant negative correlation between adiponectin and E-selectin ( P = .0001). Adipose tissue in T2DM obese patients may contribute to the pathogenesis of CHD.
Prevalence of Abdominal Wall Hernia in Participants With Abdominal Aortic Aneurysm Versus Peripheral Arterial Disease—A Population-Based Study
Authors: Pannu Rajmony , McPhail Ian R.
Published: May 2011

Small studies suggest an association between abdominal aortic aneurysms (AAAs) and hernias, possibly related to connective tissue weakness. We evaluated the association between AAA and abdominal wall hernia (AWH), using peripheral arterial disease (PAD) patients as controls, in Olmsted County, Minnesota. In a retrospective cohort study we queried the electronic medical records for the diagnosis of AAA. The resulting data were then queried for prevalence of AWH. The same set of queries was repeated for PAD. Occurrence of AWH in the 2 groups was compared using the chi-square test. Of the 187 151 patient records queried, 939 had AAA and 3465 had PAD. Abdominal wall hernia occurred in 157 (16.7%) patients with AAA and in 343 (9.9%) patients with PAD. Abdominal wall hernia was 1.7 times more prevalent in those with AAA versus PAD ( P < .0001). A history of hernia may prompt screening for AAA in some patients.
Pharmacomechanical Thrombolysis of Acute and Chronic Symptomatic Deep Vein Thrombosis: A Systematic Review of Literature
Authors: Dasari Tarun W. , Pappy Reji , Hennebry Thomas A.
Published: May 2011

Pharmacomechanical thrombolysis (PMT) is an emerging treatment option for symptomatic deep vein thrombosis (DVT). This may obviate the need for systemic or catheter-directed thrombolysis. PubMed, EMBASE, and Cochrane database search of PMT in acute and chronic symptomatic DVT was undertaken. Baseline demographic and clinical characteristics, procedural details, DVT characteristics, and procedural and clinical outcomes are presented. A total of 8 case series (n = 2528; 1998-2009) qualified for inclusion. Lower extremity symptomatic DVTs constituted the majority of the cases (>80%). Both acute (<14 days) and chronic (>14 days) DVTs were included. Procedural success was 59% to 100% and catheter-directed thrombolysis was used as an adjunct in 16% to 53%. No deaths or major bleeding complications were reported. Pharmacomechanical thrombolysis leads to the immediate resolution of clinical symptoms of DVT in the majority of patients. Pharmacomechanical thrombolysis may be a safe and novel method, when appropriate expertise and resources are available, for the treatment of symptomatic acute and chronic DVT.
Angiogenin and Hemoxygenase in Pregnancy
Authors: Karthikeyan Velore J. , Lip Gregory Y. H. , Baghdadi Sabah , Lane Deirdre A. , Beevers D. Gareth , Blann Andrew D.
Published: May 2011

The pathophysiology of hypertension and preeclampsia involves angiogenesis and endothelial damage/dysfunction, as shown by abnormal growth factors (vascular endothelial growth factor [VEGF], and its receptor sFlt-1) and von Willebrand factor (vWf) in the plasma. Angiogenin and hemoxygenase are abnormal in hypertension and angiogenesis but data on pregnancy are scant. We hypothesized altered angiogenin and hemoxygenase in 38 hypertensive pregnant women (HTPW) compared to 38 normotensive pregnant women (NTPW) and 50 nonpregnant controls (NonPCs). Plasma markers were measured by enzyme-linked immunosorbent assay (ELISA). Hypertensive pregnant women had lower VEGF than NonPCs ( P < .01), vWf was raised in both pregnant groups ( P < .01), but sFlt-1 was no different. Both angiogenin and hemoxygenase were lower in NTPW compared to NonPCs (both p<0.02). In both pregnancy groups, angiogenin correlated with vWf ( r > .33, P < .05), but in NonPCs this was not significant ( r = .13, P = .367). These changes may reflect differences in endothelial cell physiology and pathology in the hypertension in pregnancy.
Cognitive Scope of the Firm: Explaining Stakeholder Orientation From the Inside-Out
Authors: Crilly Donal
Published: May 2011

This dissertation abstract and the reflection commentary present the work of Dr. Donal Crilly. The dissertation addresses stakeholder orientation of the firm through an “inside-out” perspective. The dissertation abstract explains the research questions, setting, and methods. The reflection commentary discusses the author’s views of research process as a junior scholar.
The Effects of Weather on Walking Rates in Nine Cities
Authors: de Montigny Luc , Ling Richard , Zacharias John
Published: May 2011

This study examined whether locally felt weather had a measurable effect on the amount of walking occurring in a given locale, by examining the observed walking rate in relation to air temperature, sunlight, and precipitation. Web-based cameras in nine cities were used to collect 6,255 observations over 7 months. Walking volumes and levels of precipitation and sunlight were captured by visual inspection; air temperature was obtained from local meteorological stations. A quasi-Poisson regression model to test the relationship between counts of pedestrians and weather conditions revealed that all three weather variables had significant associations with fluctuations in volumes of pedestrians, when controlling for city and elapsed time. A 5°C increase in temperature was associated with a 14% increase in pedestrians. A shift from snow to dry conditions was associated with an increase of 23%, and a 5% increase in sunlit area was associated with a 2% increase.