bluuebunny/crossref_metadata_2025 huggingface dataset:
Indication for a Radical Intermediate Preceding the Signaling State in the LOV Domain Photocycle†
Authors: Bauer Christian , Rabl Carl‐Roland , Heberle Joachim , Kottke Tilman
Published: January 2011

The blue light photoreceptor phototropin mediates crucial processes in plants leading to optimization of photosynthesis. Phototropin comprises two flavin mononucleotide‐binding LOV (light‐, oxygen‐, or voltage‐sensitive) domains. The LOV domains undergo a photocycle upon illumination, in which two intermediates have been detected by UV/Vis spectroscopy. The triplet excited state of flavin is formed and decays within a few microseconds into a photoadduct with an adjacent cysteine, which represents the signaling state of the LOV domain. For bond formation of the photoadduct, several reaction pathways have been proposed, but evidence for an intermediate at ambient conditions has not been found. Here, we performed nanosecond time‐resolved UV/Vis spectroscopy on the phototropin‐LOV1 domain from Chlamydomonas reinhardtii. We designed a flow cell which was used to efficiently replace the sample after each photoexcitation because the cycling time is in the order of hundreds of seconds. The comparison of difference spectra of the wild type with those of the C57S mutant that produces only the triplet excited state revealed the existence of an additional intermediate between the triplet and the adduct state. This intermediate exhibits spectral properties similar to a neutral flavin radical. This finding supports a reaction mechanism involving a neutral radical pair.
General Suppression of
Escherichia coli
O157:H7 in Sand-Based Dairy Livestock Bedding
Authors: Westphal Andreas , Williams Michele L. , Baysal-Gurel Fulya , LeJeune Jeffrey T. , McSpadden Gardener Brian B.
Published: January 2011

Sand bedding material is frequently used in dairy operations to reduce the occurrence of mastitis and enhance cow comfort. One objective of this work was to determine if sand-based bedding also supported the microbiologically based suppression of an introduced bacterial pathogen. Bedding samples were collected in summer, fall, and winter from various locations within a dairy operation and tested for their ability to suppress introduced populations of
Escherichia coli
O157:H7. All sources of bedding displayed a heat-sensitive suppressiveness to the pathogen. Differences in suppressiveness were also noted between different samples at room temperature. At just 1 day postinoculation (dpi), the recycled sand bedding catalyzed up to a 1,000-fold reduction in
E. coli
counts, typically 10-fold greater than the reduction achieved with other substrates, depending on the sampling date. All bedding substrates were able to reduce
E. coli
populations by over 10,000-fold within 7 to 15 dpi, regardless of sampling date. Terminal restriction fragment length polymorphism (T-RFLP) analysis was used to identify bacterial populations potentially associated with the noted suppression of
E. coli
O157:H7 in sand bedding. Eleven terminal restriction fragments (TRFs) were overrepresented in paired comparisons of suppressive and nonsuppressive specimens at multiple sampling points, indicating that they may represent environmentally stable populations of pathogen-suppressing bacteria. Cloning and sequencing of these TRFs indicated that they represent a diverse subset of bacteria, belonging to the
Cytophaga-Flexibacter-Bacteroidetes
,
Gammaproteobacteria
, and
Firmicutes
, only a few of which have previously been identified in livestock manure. Such data indicate that microbial suppression may be harnessed to develop new options for mitigating the risk and dispersal of zoonotic bacterial pathogens on dairy farms.
Diverse
Borrelia burgdorferi
Strains in a Bird-Tick Cryptic Cycle
Authors: Hamer Sarah A. , Hickling Graham J. , Sidge Jennifer L. , Rosen Michelle E. , Walker Edward D. , Tsao Jean I.
Published: January 2011

The blacklegged tick
Ixodes scapularis
is the primary vector of the most prevalent vector-borne zoonosis in North America, Lyme disease (LD). Enzootic maintenance of the pathogen
Borrelia burgdorferi
by
I. scapularis
and small mammals is well documented, whereas its “cryptic” maintenance by other specialist ticks and wildlife hosts remains largely unexplored because these ticks rarely bite humans. We quantified
B. burgdorferi
infection in a cryptic bird-rabbit-tick cycle. Furthermore, we explored the role of birds in maintaining and moving
B. burgdorferi
strains by comparing their genetic diversity in this cryptic cycle to that found in cycles vectored by
I. scapularis.
We examined birds, rabbits, and small mammals for ticks and infection over a 4-year period at a focal site in Michigan, 90 km east of a zone of
I. scapularis
invasion. We mist netted 19,631 birds that yielded 12,301 ticks, of which 86% were
I. dentatus
, a bird-rabbit specialist. No resident wildlife harbored
I. scapularis
, and yet 3.5% of bird-derived ticks, 3.6% of rabbit-derived ticks, and 20% of rabbit ear biopsy specimens were infected with
B. burgdorferi
. We identified 25 closely related
B. burgdorferi
strains using an rRNA gene intergenic spacer marker, the majority (68%) of which had not been reported previously. The presence of strains common to both cryptic and endemic cycles strongly implies bird-mediated dispersal. Given continued large-scale expansion of
I. scapularis
populations, we predict that its invasion into zones of cryptic transmission will allow for bridging of novel pathogen strains to humans and animals.
Prevalence and Characterization of Non-O157 Shiga Toxin-ProducingEscherichia coliIsolates from Commercial Ground Beef in the United States
Authors: Bosilevac Joseph M. , Koohmaraie Mohammad
Published: January 2011

Escherichia coliO157:H7 is a Shiga toxin (stx)-producingE. coli(STEC) strain that has been classified as an adulterant in U.S. beef. However, numerous other non-O157 STEC strains are associated with diseases of various severities and have become an increasing concern to the beef industry, regulatory officials, and the public. This study reports on the prevalence and characterization of non-O157 STEC in commercial ground beef samples (n= 4,133) obtained from numerous manufacturers across the United States over a period of 24 months. All samples were screened by DNA amplification for the presence of Shiga toxin genes, which were present in 1,006 (24.3%) of the samples. Then, culture isolation of an STEC isolate from all samples that containedstx1and/orstx2was attempted. Of the 1,006 positive ground beef samples screened forstx, 300 (7.3% of the total of 4,133) were confirmed to have at least one strain of STEC present by culture isolation. In total, 338 unique STEC isolates were recovered from the 300 samples that yielded an STEC isolate. All unique STEC isolates were serotyped and were characterized for the presence of known virulence factors. These included Shiga toxin subtypes, intimin subtypes, and accessory virulence factors related to adherence (saa,iha,lifA), toxicity (cnf,subA,astA), iron acquisition (chuA), and the presence of the large 60-MDa virulence plasmid (espP,etpD,toxB,katP,toxB). The isolates were also characterized by use of a pathogenicity molecular risk assessment (MRA; based on the presence of various O-islandnlegenes). Results of this characterization identified 10 STEC isolates (0.24% of the 4,133 total) that may be considered a significant food safety threat, defined by the presence ofeae,subA, andnlegenes.
A Novel Sterol Desaturase-Like Protein Promoting Dealkylation of Phytosterols in Tetrahymena thermophila
Authors: Tomazic Mariela L. , Najle Sebastián R. , Nusblat Alejandro D. , Uttaro Antonio D. , Nudel Clara B.
Published: January 2011

The gene TTHERM_00438800 (
DES24
) from the ciliate
Tetrahymena thermophila
encodes a protein with three conserved histidine clusters, typical of the fatty acid hydroxylase superfamily. Despite its high similarity to sterol desaturase-like enzymes, the phylogenetic analysis groups Des24p in a separate cluster more related to bacterial than to eukaryotic proteins, suggesting a possible horizontal gene transfer event. A somatic knockout of
DES24
revealed that the gene encodes a protein, Des24p, which is involved in the dealkylation of phytosterols. Knocked-out mutants were unable to eliminate the C-24 ethyl group from C
29
sterols, whereas the ability to introduce other modifications, such as desaturations at positions C-5(6), C-7(8), and C-22(23), were not altered. Although C-24 dealkylations have been described in other organisms, such as insects, neither the enzymes nor the corresponding genes have been identified to date. Therefore, this is the first identification of a gene involved in sterol dealkylation. Moreover, the knockout mutant and wild-type strain differed significantly in growth and morphology only when cultivated with C
29
sterols; under this culture condition, a change from the typical pear-like shape to a round shape and an alteration in the regulation of tetrahymanol biosynthesis were observed. Sterol analysis upon culture with various substrates and inhibitors indicate that the removal of the C-24 ethyl group in
Tetrahymena
may proceed by a mechanism different from the one currently known.
Corynebacterium glutamicum
as a Host for Synthesis and Export of
d
-Amino Acids
Authors: Stäbler Norma , Oikawa Tadao , Bott Michael , Eggeling Lothar
Published: January 2011

A number of
d
-amino acids occur in nature, and there is growing interest in their function and metabolism, as well as in their production and use. Here we use the well-established
l
-amino-acid-producing bacterium
Corynebacterium glutamicum
to study whether
d
-amino acid synthesis is possible and whether mechanisms for the export of these amino acids exist. In contrast to
Escherichia coli
,
C. glutamicum
tolerates
d
-amino acids added extracellularly. Expression of
argR
(encoding the broad-substrate-specific racemase of
Pseudomonas taetrolens
) with its signal sequence deleted results in cytosolic localization of ArgR in
C. glutamicum
. The isolated enzyme has the highest activity with lysine (100%) but also exhibits activity with serine (2%). Upon overexpression of
argR
in an
l
-arginine,
l
-ornithine, or
l
-lysine producer, equimolar mixtures of the
d
- and
l
-enantiomers accumulated extracellularly. Unexpectedly,
argR
overexpression in an
l
-serine producer resulted in extracellular accumulation of a surplus of
d
-serine (81 mM
d
-serine and 37 mM
l
-serine) at intracellular concentrations of 125 mM
d
-serine plus 125 mM
l
-serine. This points to a nonlimiting ArgR activity for intracellular serine racemization and to the existence of a specific export carrier for
d
-serine. Export of
d
-lysine relies fully on the presence of
lysE
, encoding the exporter for
l
-lysine, which is apparently promiscuous with respect to the chirality of lysine. These data show that
d
-amino acids can also be produced with
C. glutamicum
and that in special cases, due to specific carriers, even a preferential extracellular accumulation of this enantiomer is possible.
The ColR/ColS Two-Component System Plays Multiple Roles in the Pathogenicity of the Citrus Canker Pathogen
Xanthomonas citri
subsp.
citri
Authors: Yan Qing , Wang Nian
Published: January 2011

Bacterial citrus canker disease, which is caused by
Xanthomonas citri
subsp.
citri
, is one of the most devastating diseases of citrus plants. In this study, we characterized the role of the two-component regulatory system ColR/ColS in the pathogenicity of
X. citri
subsp.
citri. colS
mutants (256A10 and 421E7),
colR
mutants (386C6 and 417E10), and a
colR colS
double mutant (306DSR) all lost pathogenicity and produced no symptoms on grapefruit leaves inoculated by either pressure infiltration or the spray method. The pathogenicity defect of the
colS
,
colR
, and
colR colS
mutants could be complemented using the wild-type
colS
,
colR
, and
colR colS
genes, respectively. Mutation of
colS
or
colR
significantly reduced
X. citri
subsp.
citri
growth
in planta
. The ColR/ColS system also played important roles in bacterial biofilm formation in glass tubes and on leaf surfaces, lipopolysaccharide (LPS) production, catalase activity, and tolerance of environmental stress, including phenol, copper, and hydrogen peroxide. Furthermore, quantitative reverse transcription-PCR assays demonstrated that the ColR/ColS system positively regulated the expression of important virulence genes, including
hrpD
6,
hpaF
, the O-antigen LPS synthesis gene
rfbC
, and the catalase gene
katE
. Overall, our data indicate that the two-component regulatory system ColR/ColS is critical for
X. citri
subsp.
citri
virulence, growth
in planta
, biofilm formation, catalase activity, LPS production, and resistance to environmental stress.
The influence of game scheduling on medical encounters at the USA Cup soccer tournament
Authors: Waibel Nathan G , Roberts William O , Lunos Scott
Published: January 2011

Objective

To investigate the influence of playing multiple games on multiple days on youth soccer medical encounter rates.

Design

Prospective cohort survey study.

Setting

Medical facility at the 2008 Schwan's USA Cup soccer tournament.

Participants

Players presenting to the medical facility for game-related medical evaluation.

Assessment of risk factors

Date, game and half of game for each medical encounter.

Main outcome measures

Game play-related medical encounters per 1000 match hours (MH).

Results

211 players surveyed with 195 eligible and completed questionnaires. There were 4.06, 5.14 and 3.92 medical encounters/1000 MH on 11, 12 and 13 July, respectively, with no significant difference in injury incidence. There was no difference in medical encounter rates of second games compared with first games of the day (p=0.126). Daily medical encounter rates were 5.65, 8.95, 7.83, 6.94 and 4.62/1000 MH on 15, 16, 17, 18 and 19 July, respectively, with statistically significant differences on 16 July (p<0.001) and 17 July (p=0.022) compared with 15 July. Encounter rates of second games compared with first games of the day showed no difference (p=0.385). A linear test for trend from 15 to 19 July was not significant (p=0.092).

Conclusions

The USA Cup format did not show either increased medical encounter rates from the cumulative total of games played or a consistently increased rate in the second game of the day compared with the first. Players, coaches, parents and administrators can feel confident that this tournament format does not pose an additional risk of injury.
Non-fatal conductive energy device-related injuries treated in US emergency departments, 2005–2008
Authors: Haileyesus Tadesse , Annest Joseph L , Mercy James A
Published: January 2011

This paper provides the first US estimates and rates of non-fatal conductive energy device (CED)-related (eg, Taser) injuries relative to other types of legal intervention injuries treated in hospital emergency departments (EDs). The data used for this study were from the National Electronic Injury Surveillance System (NEISS), including the Firearm Injury Surveillance Study (NEISS–FISS) and the All Injury Program (NEISS–AIP). Of an average annual 75 000 suspects treated for non-fatal legal intervention injuries, 11% had injuries that were associated with the use of a CED or Taser. Of the suspects with non-fatal CED-related injuries, 90.1% were males, 72.6% were 20–44 years of age, and 55.2% were injured to the trunk. Most suspects with CED-related injuries (93.6%) were treated and released from the hospital ED. The authors conclude that NEISS is a useful data source for CED-related injuries in the US; estimates from NEISS emphasise the importance of implementing CED safety guidelines by law enforcement officers and training of medical personnel to help reduce the risk of severe injury and potential adverse health consequences.
Clinical risk scores to guide perioperative management
Authors: Barnett Sarah , Moonesinghe Suneetha Ramani
Published: January 2011

Perioperative morbidity is associated with reduced long term survival. Comorbid disease, cardiovascular illness, and functional capacity can predispose patients to adverse surgical outcomes. Accurate risk stratification would facilitate informed patient consent and identify those individuals who may benefit from specific perioperative interventions. The ideal clinical risk scoring system would be objective, accurate, economical, simple to perform, based entirely on information available preoperatively, and suitable for patients undergoing both elective and emergency surgery. The POSSUM (Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity) scoring systems are the most widely validated perioperative risk predictors currently utilised; however, their inclusion of intra- and postoperative variables precludes validation for preoperative risk prediction. The Charlson Index has the advantage of consisting exclusively of preoperative variables; however, its validity varies in different patient cohorts. Risk models predicting cardiac morbidity have been extensively studied, despite the relatively uncommon occurrence of postoperative cardiac events. Probably the most widely used cardiac risk score is the Lee Revised Cardiac Risk Index, although it has limited validity in some patient populations and for non-cardiac outcomes. Bespoke clinical scoring systems responding to dynamic changes in population characteristics over time, such as those developed by the American College of Surgeons National Surgical Quality Improvement Program, are more precise, but require considerable resources to implement. The combination of objective clinical variables with information from novel techniques such as cardiopulmonary exercise testing and biomarker assays, may improve the predictive precision of clinical risk scores used to guide perioperative management.
Acute presentations of HIV are still missed in low prevalence areas
Authors: Ratcliffe L , Thomas S , Beeching N J , Phillips-Howard P A , Taegtmeyer M
Published: January 2011

Objectives

To evaluate missed opportunities and delays in the diagnosis of HIV in a low prevalence setting over a 24 year period.

Methods

Patients with acute presentations of HIV were included in a retrospective note based review. Data were compared from acute presentations in 1985–2001 (88/241 new patients) with 2005–2007 (99/136 new patients). The number of recorded clinical and laboratory clues to infection and subsequent time delays to diagnosis of HIV were evaluated.

Results

The findings reflect the shifting demographics of HIV in the UK over the past two decades, exemplified by an eightfold increase in tuberculosis at presentation. Despite recording clinical stigmata of HIV (clues) in the notes, the number of missed clues increased, and many clinicians failed to request HIV testing. The median delay between presentation and diagnosis reduced from 5 to 1 day (p<0.001), and mortality dropped from 14% to 4% among patients presenting with acute symptoms. However, there was still a delay of more than 30 days before diagnosis for almost one in five patients.

Conclusions

Despite some improvement and better awareness, there are still significant delays before hospital doctors consider the diagnosis of HIV for patients in low prevalence areas, even among some patient groups with high risk. Hospitals should consider moving to opt-out routine HIV testing of all medical admissions.
What makes a Salmonella strain epidemic? An expert opinion workshop
Authors: Brouwer A. , Hill A. , Woodward M. J.
Published: January 2011

An expert opinion workshop was held on the subject of the cause, identification and control of new and emerging Salmonella strains. Experts were invited to complete questionnaires, contribute to structured discussions and take part in cluster group tasks. Outputs of the workshop included that, with current surveillance methods, it might take up to 2.5 years from the first introduction of a new strain into the UK livestock population to its identification as a human epidemic strain. In order to reduce the time to detection and provide more effective control options, several recommendations were made, including better back‐tracing of human cases to their source, which would require more effective communication between those responsible for human and veterinary surveillance.
Image segmentation and classification of Landsat Thematic Mapper data using a sampling approach for forest cover assessmentThis article is one of a selection of papers from Extending Forest Inventory and Monitoring over Space and Time.
Authors: Hirata Yasumasa , Takahashi Tomoaki
Published: January 2011

Remote sensing surveys for estimating forest cover may be divided into two approaches: wall-to-wall and sampling. Sampling approaches offer a practical alternative to wall-to-wall mapping, but estimates of forest cover may be affected by the sampling rate of the estimation area. This study aimed to obtain stable estimates of forest cover from satellite data using object-oriented classification at the national level. We investigated a suitable value for the scale parameter in object-oriented classification using eCognition software to identify land cover types, and we evaluated the sampling rate for estimating forest cover at the national level. We used eight different scale parameters when applying object-oriented classification to Landsat data for a set of forty-six 10 km × 10 km sampling tiles centered at each degree of latitude and longitude in Japan. The scale parameter of 10 or less was found suitable for obtaining objects with areas of about 5 ha. Overall accuracy in classification was greater than 75% and greatest when the scale parameter was between 6 and 10. We then analyzed the entire land area of Japan using 10 km × 10 km tiles to evaluate the optimum sampling rate for estimating forest cover. A sampling rate greater than 20% was required to stably estimate forest cover in Japan.
Differences in forest area classification based on tree tally from variable- and fixed-radius plots
Authors: Azuma David , Monleon Vicente J.
Published: January 2011

In forest inventory, it is not enough to formulate a definition; it is also necessary to define the “measurement procedure.” In the classification of forestland by dominant cover type, the measurement design (the plot) can affect the outcome of the classification. We present results of a simulation study comparing classification of the dominant cover type between fixed- and variable-radius plot designs. We also show the effect of species distribution and partially sampled plots on these classifications. Plot type, area sampled, and the way in which the species are distributed influence the outcome of the classification. Thus, estimated changes in forest area may be an artifact of plot design changes, rather than actual population change.
The extracellular calcium-sensing receptor is required for cholecystokinin secretion in response to l-phenylalanine in acutely isolated intestinal I cells
Authors: Liou Alice P. , Sei Yoshitatsu , Zhao Xilin , Feng Jianying , Lu Xinping , Thomas Craig , Pechhold Susanne , Raybould Helen E. , Wank Stephen A.
Published: January 2011

The extracellular calcium-sensing receptor (CaSR) has recently been recognized as an l-amino acid sensor and has been implicated in mediating cholecystokinin (CCK) secretion in response to aromatic amino acids. We investigated whether direct detection of l-phenylalanine (l-Phe) by CaSR results in CCK secretion in the native I cell. Fluorescence-activated cell sorting of duodenal I cells from CCK-enhanced green fluorescent protein (eGFP) transgenic mice demonstrated CaSR gene expression. Immunostaining of fixed and fresh duodenal tissue sections confirmed CaSR protein expression. Intracellular calcium fluxes were CaSR dependent, stereoselective for l-Phe over d-Phe, and responsive to type II calcimimetic cinacalcet in CCK-eGFP cells. Additionally, CCK secretion by an isolated I cell population was increased by 30 and 62% in response to l-Phe in the presence of physiological (1.26 mM) and superphysiological (2.5 mM) extracellular calcium concentrations, respectively. While the deletion of CaSR from CCK-eGFP cells did not affect basal CCK secretion, the effect of l-Phe or cinacalcet on intracellular calcium flux was lost. In fact, both secretagogues, as well as superphysiological Ca2+, evoked an unexpected 20–30% decrease in CCK secretion compared with basal secretion in CaSR−/− CCK-eGFP cells. CCK secretion in response to KCl or tryptone was unaffected by the absence of CaSR. The present data suggest that CaSR is required for hormone secretion in the specific response to l-Phe by the native I cell, and that a receptor-mediated mechanism may inhibit hormone secretion in the absence of a fully functional CaSR.
Skeletal muscle blood flow and oxygen uptake at rest and during exercise in humans: a pet study with nitric oxide and cyclooxygenase inhibition
Authors: Ilkka Heinonen , Bengt Saltin , Jukka Kemppainen , Sipilä Hannu T. , Vesa Oikonen , Pirjo Nuutila , Juhani Knuuti , Kari Kalliokoski , Ylva Hellsten
Published: January 2011

The aim of the present study was to determine the effect of nitric oxide and prostanoids on microcirculation and oxygen uptake, specifically in the active skeletal muscle by use of positron emission tomography (PET). Healthy males performed three 5-min bouts of light knee-extensor exercise. Skeletal muscle blood flow and oxygen uptake were measured at rest and during the exercise using PET with H2O15 and 15O2 during: 1) control conditions; 2) nitric oxide synthase (NOS) inhibition by arterial infusion of NG-monomethyl-l-arginine (l-NMMA), and 3) combined NOS and cyclooxygenase (COX) inhibition by arterial infusion of l-NMMA and indomethacin. At rest, inhibition of NOS alone and in combination with indomethacin reduced ( P < 0.05) muscle blood flow. NOS inhibition increased ( P < 0.05) limb oxygen extraction fraction (OEF) more than the reduction in muscle blood flow, resulting in an ∼20% increase ( P < 0.05) in resting muscle oxygen consumption. During exercise, muscle blood flow and oxygen uptake were not altered with NOS inhibition, whereas muscle OEF was increased ( P < 0.05). NOS and COX inhibition reduced ( P < 0.05) blood flow in working quadriceps femoris muscle by 13%, whereas muscle OEF and oxygen uptake were enhanced by 51 and 30%, respectively. In conclusion, by specifically measuring blood flow and oxygen uptake by the use of PET instead of whole limb measurements, the present study shows for the first time in humans that inhibition of NO formation enhances resting muscle oxygen uptake and that combined inhibition of NOS and COX during exercise increases muscle oxygen uptake.
Narrowing a region on rat chromosome 13 that protects against hypertension in Dahl SS-13BNcongenic strains
Authors: Moreno Carol , Williams Jan M. , Lu Limin , Liang Mingyu , Lazar Jozef , Jacob Howard J. , Cowley Allen W. , Roman Richard J.
Published: January 2011

Transfer of chromosome 13 from the Brown Norway (BN) rat onto the Dahl salt-sensitive (SS) genetic background attenuates the development of hypertension, but the genes involved remain to be identified. The purpose of the present study was to confirm by telemetry that a congenic strain [SS.BN-(D13Hmgc37-D13Got22)/Mcwi, line 5], carrying a 13.4-Mb segment of BN chromosome 13 from position 32.4 to 45.8 Mb, is protected from the development of hypertension and then to narrow the region of interest by creating and phenotyping 11 additional subcongenic strains. Mean arterial pressure (MAP) rose from 118 ± 1 to 186 ± 5 mmHg in SS rats fed a high-salt diet (8.0% NaCl) for 3 wk. Protein excretion increased from 56 ± 11 to 365 ± 37 mg/day. In contrast, MAP only increased to 152 ± 9 mmHg in the line 5 congenic strain. Six subcongenic strains carrying segments of BN chromosome 13 from 32.4 and 38.2 Mb and from 39.9 to 45.8 Mb were not protected from the development of hypertension. In contrast, MAP was reduced by ∼30 mmHg in five strains, carrying a 1.9-Mb common segment of BN chromosome 13 from 38.5 to 40.4 Mb. Proteinuria was reduced by ∼50% in these strains. Sequencing studies did not identify any nonsynonymous single nucleotide polymorphisms in the coding region of the genes in this region. RT-PCR studies indicated that 4 of the 13 genes in this region were differentially expressed in the kidney of two subcongenic strains that were partially protected from hypertension vs. those that were not. These results narrow the region of interest on chromosome 13 from 13.4 Mb (159 genes) to a 1.9-Mb segment containing only 13 genes, of which 4 are differentially expressed in strains partially protected from the development of hypertension.
Relation between QT interval variability and cardiac sympathetic activity in hypertension
Authors: Baumert Mathias , Schlaich Markus P. , Nalivaiko Eugene , Lambert Elisabeth , Sari Carolina Ika , Kaye David M. , Elser Murray D. , Sanders Prashanthan , Lambert Gavin
Published: January 2011

Elevated QT interval variability is a predictor of malignant ventricular arrhythmia, but the underlying mechanisms are incompletely understood. A recent study in dogs with pacing-induced heart failure suggests that QT variability is linked to cardiac sympathetic nerve activity. The aim of this study was to determine whether increased cardiac sympathetic activity is associated with increased beat-to-beat QT interval variability in patients with essential hypertension. We recorded resting norepinephrine (NE) spillover into the coronary sinus and single-lead, short-term, high-resolution, body-surface ECG in 23 patients with essential hypertension and 9 normotensive control subjects. To assess beat-to-beat QT interval variability, we calculated the overall QT variability (QTVN) as well as the QT variability index (QTVi). Cardiac NE spillover (12.2 ± 6.5 vs. 20.7 ± 14.7, P = 0.03) and QTVi (−1.75 ± 0.36 vs. −1.42 ± 0.50, P = 0.05) were significantly increased in hypertensive patients compared with normotensive subjects. QTVN was significantly correlated with cardiac NE spillover ( r2 = 0.31, P = 0.001), with RR variability ( r2 = 0.20, P = 0.008), and with systolic blood pressure ( r2 = 0.16, P = 0.02). Linear regression analysis identified the former two as independent predictors of QTVN. In conclusion, elevated repolarization lability is directly associated with sympathetic cardiac activation in patients with essential hypertension.
Novel Role for STAT3 in Transcriptional Regulation of NK Immune Cell Targeting Receptor MICA on Cancer Cells
Authors: Bedel Romain , Thiery-Vuillemin Antoine , Grandclement Camille , Balland Jeremy , Remy-Martin Jean-Paul , Kantelip Bernadette , Pallandre Jean-René , Pivot Xavier , Ferrand Christophe , Tiberghien Pierre , Borg Christophe
Published: January 2011

The role of natural killer group 2, member D receptor (NKG2D)–expressing natural killer (NK) cells in tumor immunosurveillance is now well established. Nevertheless, tumor progression occurs despite tumor immunosurveillance, leading to cancer persistence in immunocompetent hosts. STAT3 plays a pivotal role both in oncogenic functions and in immunosuppression. In this study, we investigated the role of STAT3 in suppressing NK cell–mediated immunosurveillance. Using a colorectal cancer cell line (HT29) that can poorly activate NK, we neutralized STAT3 with pharmacologic inhibitors or siRNA and found that this led to an increase in NK degranulation and IFN-γ production in a TGF-β1–independent manner. Exposure to NKG2D-neutralizing antibodies partially restored STAT3 activity, suggesting that it prevented NKG2D-mediated NK cell activation. On this basis, we investigated the expression of NKG2D ligands after STAT3 activation in HT29, mesenchymal stem cells, and activated lymphocytes. The NK cell recognition receptor MHC class I chain–related protein A (MICA) was upregulated following STAT3 neutralization, and a direct interaction between STAT3 and the MICA promoter was identified. Because cross-talk between DNA damage repair and NKG2D ligand expression has been shown, we assessed the influence of STAT3 on MICA expression under conditions of genotoxic stress. We found that STAT3 negatively regulated MICA expression after irradiation or heat shock, including in lymphocytes activated by CD3/CD28 ligation. Together, our findings reveal a novel role for STAT3 in NK cell immunosurveillance by modulating the MICA expression in cancer cells. Cancer Res; 71(5); 1615–26. ©2011 AACR.
Enhancement of T-cell–Mediated Antitumor Response: Angiostatic Adjuvant to Immunotherapy against Cancer
Authors: Dings Ruud P.M. , Vang Kieng B. , Castermans Karolien , Popescu Flavia , Zhang Yan , oude Egbrink Mirjam G.A. , Mescher Matthew F. , Farrar Michael A. , Griffioen Arjan W. , Mayo Kevin H.
Published: January 2011

Purpose: Tumor-released proangiogenic factors suppress endothelial adhesion molecule (EAM) expression and prevent leukocyte extravasation into the tumor. This is one reason why immunotherapy has met with limited success in the clinic. We hypothesized that overcoming EAM suppression with angiogenesis inhibitors would increase leukocyte extravasation and subsequently enhance the effectiveness of cellular immunotherapy.

Experimental Design: Intravital microscopy, multiple color flow cytometry, immunohistochemistry, and various tumor mouse (normal and T-cell deficient) models were used to investigate the temporal dynamics of cellular and molecular events that occur in the tumor microenvironment during tumor progression and angiostatic intervention.

Results: We report that while EAM levels and T-cell infiltration are highly attenuated early on in tumor growth, angiostatic therapy modulates these effects. In tumor models with normal and T-cell–deficient mice, we show the active involvement of the adaptive immune system in cancer and differentiate antiangiogenic effects from antiangiogenic mediated enhancement of immunoextravasation. Our results indicate that a compromised immune response in tumors can be obviated by the use of antiangiogenic agents. Finally, with adoptive transfer studies in mice, we show that a phased combination of angiostatic therapy and T-cell transfer significantly (P < 0.0013) improves tumor growth inhibition.

Conclusions: This research contributes to understand the cellular mechanism of action of angiostatic agents and the immune response within the tumor microenvironment, in particular as a consequence of the temporal dynamics of EAM levels. Moreover, our results suggest that adjuvant therapy with angiogenesis inhibitors holds promise for cellular immunotherapy in the clinic. Clin Cancer Res; 17(10); 3134–45. ©2011 AACR.
sFLT01: A Novel Fusion Protein with Antiangiogenic Activity
Authors: Bagley Rebecca G. , Kurtzberg Leslie , Weber William , Nguyen Tri-Hung , Roth Stephanie , Krumbholz Roy , Yao Min , Richards Brenda , Zhang Mindy , Pechan Peter , Schmid Steve , Scaria Abraham , Kaplan Johanne , Teicher Beverly A.
Published: January 2011

sFLT01 is a novel fusion protein that consists of the VEGF/PlGF (placental growth factor) binding domain of human VEGFR1/Flt-1 (hVEGFR1) fused to the Fc portion of human IgG1 through a polyglycine linker. It binds to both human VEGF (hVEGF) and human PlGF (hPlGF) and to mouse VEGF (mVEGF) and mouse PlGF (mPlGF). In vitro, sFLT01 inhibited the proliferation of human umbilical vein endothelial cells and pericytes stimulated by either hVEGF or hPlGF. In vivo, sFLT01 had robust and significant antitumor activity in numerous preclinical subcutaneous tumor models including H460 non–small cell lung carcinoma, HT29 colon carcinoma, Karpas 299 lymphoma, MOLM-13 AML (acute myeloid leukemia), 786-O, and RENCA renal cell carcinoma (RCC). sFLT01 also increased median survival in the orthotopic RENCA RCC model. sFLT01 had strong antiangiogenic activity and altered intratumoral microvessel density, blood vessel lumen size and perimeter, and vascular and vessel areas in RCC models. sFLT01 treatment resulted in fewer endothelial cells and pericytes within the tumor microenvironment. sFLT01 in combination with cyclophosphamide resulted in greater inhibition of tumor growth than either agent used alone as a monotherapy in the A673 Ewing's sarcoma model. Gene expression profiling indicated that the molecular changes in the A673 sarcoma tumors are similar to changes observed under hypoxic conditions. sFLT01 is an innovative fusion protein that possessed robust antitumor and antiangiogenic activities in preclinical cancer models. It is a dual targeting agent that neutralizes both VEGF and PlGF and, therefore, has potential as a next generation antiangiogenic therapeutic for oncology. Mol Cancer Ther; 10(3); 404–15. ©2011 AACR.
Encephalitis-Associated Pandemic A (H1N1) 2009 in a Kuwaiti Girl
Authors: Al-Baghli Fawaz , Al-Ateeqi Wafaa
Published: January 2011

Objective: To report an 11-year-old girl with encephalitis-associated pandemic influenza A (H1N1) 2009 virus infection. Clinical Presentation and Intervention: An 11-year-old girl presented with a 6-day history of influenza-like illness followed by an altered mental status for 1 day. She tested positive for pandemic influenza A (H1N1) 2009 virus by PCR of her nasal swab. Her CSF analysis was completely normal, including PCR for pandemic influenza A virus. Her brain MRI and EEG showed evidence suggestive of encephalitis. She was treated with oral Oseltamivir with good recovery. Conclusion: This case report shows that neurological complications can occur after respiratory tract infection with pandemic influenza A (H1N1) 2009 virus.
Left Ventricular Hypertrophy in Incident Dialysis Patients Randomized to Treatment with Hemofiltration or Hemodialysis: Results from the ProFil Study
Authors: Alvestrand Anders , Ledebo Ingrid , Hagerman Inger , Wingren Kerstin , Mattsson Eva , Qureshi Abdul Rashid , Gutierrez Alberto ,   for the ProFil Study Investigators
Published: January 2011

Introduction: Left ventricular hypertrophy (LVH) is present in a majority of hemodialysis (HD) patients and is among the strongest risk factors for cardiovascular events and mortality. Hemofiltration (HF), a purely convective dialysis treatment, has been associated with enhanced hemodynamic stability compared with HD, possibly as a result of a more physiologic removal of fluid and solutes. Methods: In a randomized controlled study conducted at ten dialysis centers in Sweden and Denmark, incident patients (HD <3 months) without clinical signs or history of cardiovascular disease were randomized to treatment with either online, predilution HF or low-flux HD. The primary endpoint was change in left ventricular mass index (LVMI), as measured by two-dimensional M-mode and Doppler echocardiography. Results: The analyses included 34 patients (18 HF, 16 HD) followed for up to 2 years. At baseline, 65% of the patients had LVH, but LVMI did not differ between the study groups. In the HF group, LVMI decreased by 22 ± 48 g/m2 during a mean treatment time of 19 ± 7 months, while in the HD group the decrease was 15 ± 57 g/m2 during 16 ± 7 months. As analyzed by MANOVA (mixed model), the difference in LVMI over the whole period was statistically significant (p = 0.03) with a more favorable outcome in HF. Blood pressure and other study variables did not differ between the groups, but at baseline and throughout the study, HF patients required heavier antihypertensive treatment. Conclusions: In incident dialysis patients, long-term predilution HF, a purely convective dialysis treatment, is associated with a significantly more favorable development of LVMI compared with regular low-flux HD. Considering the predictive strength of LVMI as a risk factor, the quantitative difference between the treatments is of clinical importance.
QT/RR Coherence Is Associated with Testosterone Levels in Men with Chronic Spinal Cord Injury
Authors: La Fountaine Michael F. , Wecht Jill M. , Cirnigliaro Christopher M. , Kirshblum Steven C. , Spungen Ann M. , Bauman William A.
Published: January 2011

Aim: To evaluate the effect of hypogonadism on temporal characteristics of ventricular repolarization (VR) and QT/RR coherence in men with spinal cord injury (SCI). Methods: Thirty-four men with SCI (>1 year postinjury) were studied. After clinical evaluation, 20 subjects were diagnosed as hypogonadal and 14 as eugonadal. QT and RT time, heart rate (HR), and Bazett QTc were determined from a digital electrocardiogram during quiet rest and a cold pressor test (CPT). QT/RR coherence was calculated across three spectral frequencies including mean (Mean Coh; 0–0.2 Hz), low (LF Coh; 0.04–0.15 Hz) and high (HF Coh; 0.15–0.40 Hz). Respiration was collected via impedance pneumography. Results: No statistical differences were observed among demographics. Pairwise comparisons demonstrated a significantly reduced Mean Coh at rest in the hypogonadal group compared to the eugonadal; during the CPT, the hypogonadal group had significantly elevated Mean and HF Coh. No group main effects were observed with analysis of variance. Condition main effects were observed in QT, Mean, LF and HF Coh. Significant group-condition interactions were present in Mean and HF Coh, while trends toward significance were observed on LF Coh, HR, QT and RT. Post-hoc pairwise comparisons revealed that the change from rest to CPT in Mean, LF and HF Coh was significant in the eugonadal group, but not the hypogonadal. Conclusion: Hypogonadism in SCI appears to adversely affect temporal VR characteristics independently of QTc. QT/RR coherence suggests an autonomic synergism with testosterone. These findings may represent a pathologic sequelae that precedes the well-documented hypogonadic effects on QTc.
Worsening of Diet-Induced Atherosclerosis in a New Model of Transgenic Rabbit Expressing the Human Plasma Phospholipid Transfer Protein
Authors: Masson David , Deckert Valérie , Gautier Thomas , Klein Alexis , Desrumaux Catherine , Viglietta Céline , Pais de Barros Jean-Paul , Le Guern Naig , Grober Jacques , Labbé Jérôme , Ménétrier Franck , Ripoll Pierre-Jean , Leroux-Coyau Mathieu , Jolivet Geneviève , Houdebine Louis-Marie , Lagrost Laurent
Published: January 2011

Objective—

Plasma phospholipid transfer protein (PLTP) is involved in intravascular lipoprotein metabolism. PLTP is known to act through 2 main mechanisms: by remodeling high-density lipoproteins (HDL) and by increasing apolipoprotein (apo) B–containing lipoproteins. The aim of this study was to generate a new model of human PLTP transgenic (HuPLTPTg) rabbit and to determine whether PLTP expression modulates atherosclerosis in this species that, unlike humans and mice, displays naturally very low PLTP activity.

Methods and Results—

In HuPLTPTg rabbits, the human PLTP cDNA was placed under the control of the human eF1-α gene promoter, resulting in a widespread tissue expression pattern and in increased plasma PLTP. The HuPLTPTg rabbits showed a significant increase in the cholesterol content of the plasma apoB-containing lipoprotein fractions, with a more severe trait when animals were fed a cholesterol-rich diet. In contrast, HDL cholesterol level was not modified in HuPLTPTg rabbits. Formation of aortic fatty streaks was increased in hypercholesterolemic HuPLTPTg animals as compared with nontransgenic littermates.

Conclusion—

Human PLTP expression in HuPLTPTg rabbit worsens atherosclerosis as a result of increased levels of atherogenic apoB-containing lipoproteins but not of alterations in their antioxidative protection or in cholesterol content of plasma HDL.
Race and Gender Differences in 1-Year Outcomes for Community-Dwelling Stroke Survivors With Family Caregivers
Authors: Roth David L. , Haley William E. , Clay Olivio J. , Perkins Martinique , Grant Joan S. , Rhodes J. David , Wadley Virginia G. , Kissela Brett , Howard George
Published: January 2011

Background and Purpose—

Previous research has reported worse outcomes after stroke for women and for African Americans, but few prospective population-based studies have systematically examined demographic differences on long-term stroke outcomes. Race and gender differences in 1-year stroke outcomes were examined using an epidemiologically derived sample of first-time stroke survivors from the national REasons for Geographic and Racial Differences in Stroke (REGARDS) study.

Methods—

Participants of REGARDS who reported a first-time stroke event during regular surveillance calls were interviewed by telephone and then completed an in-home evaluation approximately 1 year after the verified first-time stroke event (N=112). A primary family caregiver was also enrolled and interviewed for each stroke survivor. Measures from the in-home evaluation included previously validated stroke outcomes assessments of neurological deficits, functional impairments, and patient-reported effects of stroke in multiple domains.

Results–

African American stroke survivors were less likely to be living with their primary family caregivers than white participants. Analyses that controlled for age, education, and whether the stroke survivors lived with their primary family caregivers indicated that African Americans and women showed significantly greater deficits on multiple 1-year outcome measures compared to whites and men, respectively.

Conclusions—

Among community-dwelling stroke survivors with family caregivers, women and African Americans are at heightened risk for poor long-term outcomes 1 year after first-time stroke events. Rehabilitation services and public health policies aimed at enhancing stroke recovery rates should address these disparities in poststroke outcomes.
Stromal-Derived Factor-1α Correlates With Circulating Endothelial Progenitor Cells and With Acute Lesion Volume in Stroke Patients
Authors: Bogoslovsky Tanya , Spatz Maria , Chaudhry Aneeka , Maric Dragan , Luby Marie , Frank Joseph , Warach Steven
Published: January 2011

Background and Purpose—

Endothelial progenitor cells (EPC) are important participants of neovascularization and are mobilized through signaling with stromal-derived factor (SDF-1α), vascular endothelial growth factor (VEGF), granulocyte colony-stimulating factor, and stem cell factor. The association between EPC levels and these growth factors (GF) in acute stroke has not been previously established. We aimed to determine the association between EPC and these GF, and to elucidate a relationship between these GF and stroke severity in acute stroke patients.

Methods—

Seventeen patients were selected from 175 patients with imaging-confirmed acute ischemic stroke. EPC were quantified using CD34, CD133, and VEGF-R2 markers. Plasma VEGF, SDF-1α, granulocyte colony-stimulating factor, and stem cell factor were determined by enzyme-linked immunosorbent assay on days 1 and 3, and brain MRI was performed at baseline and on days 1 and 5 after the stroke onset.

Results—

Levels of SDF-1α strongly (
r
=0.6) correlated with the numbers of EPC subsets CD133
+
VEFG-R2
+
(
P
<0.004), CD34
+
VEGF-R2
+
(
P
<0.01), and CD34
+
CD133
+
VEGF-R2
+
(
P
<0.01) on day 1. Stem cell factor strongly (
r
=0.5) correlated with CD133
+
VEGF-R2
+
(
P
<0.05). SDF-1α moderately inversely (
r
=−0.49) correlated with baseline diffusion-weighted imaging lesion volumes (
P
<0.04). Median levels of SDF-1α (1561 pg/mL) increased (
P
<0.04) on day 3 compared to day 1 (1379 pg/mL). Similarly, VEGF at day 3 (95 pg/mL) increased (
P
<0.03) compared to day 1 (64 pg/mL).

Conclusions—

These results indicate that SDF-1α and stem cell factor correlate with an increase in EPC early in ischemic stroke patients.