bluuebunny/crossref_metadata_2025 huggingface dataset:
Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions†
Authors: Cadet Jean , Mouret Stéphane , Ravanat Jean‐Luc , Douki Thierry
Published: July 2012

The survey focuses on recent aspects of photochemical reactions to cellular DNA that are implicated through the predominant formation of mostly bipyrimidine photoproducts in deleterious effects of human exposure to sunlight. Recent developments in analytical methods have allowed accurate and quantitative measurements of the main DNA photoproducts in cells and human skin. Highly mutagenic CC and CT bipyrimidine photoproducts, including cyclobutane pyrimidine dimers and pyrimidine (6‐4) pyrimidone photoproducts (6‐4PPs) are generated in low yields with respect to TT and TC photoproducts. Another striking finding deals with the formation of Dewar valence isomers, the third class of bipyrimidine photoproducts that is accounted for by UVA‐mediated isomerization of initially UVB generated 6‐4PPs. Cyclobutadithymine (T<>T) has been unambiguously shown to be involved in the genotoxicity of UVA radiation. Thus, T<>T is formed in UVA‐irradiated cellular DNA according to a direct excitation mechanism with a higher efficiency than oxidatively generated DNA damage that arises mostly through the Type II photosensitization mechanism. C<>C and C<>T are repaired at rates intermediate between those of T<>T and 6‐4TT. Evidence has been also provided for the occurrence of photosensitized reactions mediated by exogenous agents that act either in an independent way or through photodynamic effects.
Xbox or SeXbox? An Examination of Sexualized Content in Video Games
Authors: Paul Stermer S. , Burkley Melissa
Published: July 2012

Video games often offer players a chance to visit fantastical places that could never exist in reality. However, these interactions are related to and can influence how one perceives the real world. Research has primarily focused on the relationship between violent video games and aggression, but there is another aspect of video games that could influence players: sexualized content. In this article we review the prevalence of sexualized content in video games and discuss the relationship this content has with players’ attitudes toward women. This burgeoning body of work indicates that sexualized content is both highly prevalent in video games and is linked to increased sexist attitudes and perceptions of the real world. We conclude by highlighting important questions that remain unanswered regarding the role that sexualized content has on video game players.
When does goal discrepancy induce compensatory effort? An application of self‐completion theory to social issues
Authors: Matschke Christina , Fehr Jennifer , Sassenberg Kai
Published: July 2012

The authors review research that applies self‐completion theory to goals targeting other people (as in the case of stereotyping and prejudice), goals that aim at the achievement of a certain social identity and goals based on the social identity. It is demonstrated that goal discrepancies lead to compensation for social as well as for non‐social goals. Based on self‐completion theory it is proposed that the identity‐relevance of the respective goal as well as the goal relevance of the subsequent task are of major importance considering the individuals’ compensation. The authors argue that the consideration of these factors advance our understanding of social phenomena.
Behavioral Responses to Threatening Social Comparisons: From Dastardly Deeds to Rising Above
Authors: Johnson Camille
Published: July 2012

We know that being around more successful others can threaten positive self‐views and self‐esteem. We also know that people are motivated to maintain high self‐esteem. The present article outlines how threats to self‐views, created by upward comparisons to more successful others, motivate and influence behavioral responses. In particular, it suggests that the degree to which subsequent performance situations provide an opportunity to repair threatened self‐views determine whether responses are positive or negative. When performance tasks provide an opportunity to repair self‐views, and repair seems likely, positive responses such as increased performance are likely to occur. When performance tasks do not provide an opportunity and repair seems unlikely, negative responses such as undermining others and withdrawing effort are likely to occur. Theoretical and practical implications, as well as future directions are discussed.
Lycorine hydrochloride inhibits metastatic melanoma cell‐dominant vasculogenic mimicry
Authors: Liu Ruifang , Cao Zhifei , Tu Jian , Pan Yanyan , Shang Bingxue , Zhang Gaochuan , Bao Meimei , Zhang Shasha , Yang Ping , Zhou Quansheng
Published: July 2012

Melanoma cells actively participate in tumor angiogenesis and vasculogenic mimicry. However, anti‐angiogenic therapy in patients with melanoma has not shown a significant survival gain. Thus, new anti‐melanoma angiogenic and vasculogenic drugs are highly desired. Using the metastatic melanoma cell line C8161 as a model, we explored melanoma vasculogenic inhibitors and found that lycorine hydrochloride (LH) effectively suppressed C8161 cell‐dominant formation of capillary‐like tubes in vitro and generation of tumor blood vessels in vivo with low toxicity. Mechanistic studies revealed that LH markedly hindered expression of VE‐cadherin in C8161 cells, but did not affect expression of six other important angiogenic and vasculogenic genes. Luciferase assays showed that LH significantly impeded promoter activity of the VE‐cadherin gene in a dose‐dependent manner. Together, these data suggest that LH inhibits melanoma C8161 cell‐dominant vasculogenic mimicry by reducing VE‐cadherin gene expression and diminishing cell surface exposure of the protein.
Erosive potential of sports beverages
Authors: Cochrane NJ , Yuan Y , Walker GD , Shen P , Chang CH , Reynolds C , Reynolds EC
Published: July 2012

Background:  Dental erosion is an increasingly prevalent problem in Australia, with the consumption of sports beverages suggested as a risk factor. The aim of this study was to compare the erosive potential of Australian sports beverages.

Methods:  Ten beverages were selected and analysed to determine their pH, titratable acidity and apparent degree of saturation with respect to apatite. The erosive potential of the beverages was measured by human enamel surface loss and surface softening following a 30‐minute exposure. A taste testing panel was established to determine the palatability of the sports beverages.

Results:  All sports beverages except Sukkie and Endura produced substantial surface loss and surface softening. Compared with the other sports beverages, Sukkie and Endura had a higher pH, lower titratable acidity and higher calcium content. However, Sukkie and Endura were deemed to be less palatable than the other more acidic sports beverages.

Conclusions:  The majority of the sports beverages tested produced dental erosion in this in vitro model. However, two new products Sukkie and Endura have lower erosive potential but also lower palatability.
White‐Tailed Deer (Odocoileus virginianus) as a Potential Sentinel for Human Lyme Disease in Indiana
Authors: Raizman E. A. , Holland J. D. , Shukle J. T.
Published: July 2012

We assessed the potential of white‐tailed deer (WTD) (Odocoileus virginianus) to be a sentinel for human cases of Lyme disease (LD) in Indiana using location data from a 3‐year survey of approximately 3400 hunted deer with associated tick Ixodes scapularis and Borrelia burgdorferi (Bb) data. Data on human LD cases at the county level were obtained from the Indiana Department of Health. All data were assigned to county centroids to match the resolution of the LD data before creating optimized trend surfaces for LD incidence, hunted deer count, Ixodes scapularis and Bb prevalence. To determine whether LD was spatially associated with the areas of high densities of deer, deer with Ixodes scapularis and deer with ticks infected with Bb, we used spatial analysis with distance indices (SADIE). The SADIE analysis found significant spatial association between LD and the distribution of three organismal predictor variables, that is, WTD, Ixodes ticks and Bb. Lyme disease incident rate varied between 0.08 cases per 10 000 habitants (Johnson county) and 5.9 cases per 10 000 habitants (Warren county). In conclusion, WTD can be used as an accurate and cost‐effective sentinel for human LD. This method will permit public health workers to identify potentially endemic areas independently of human case reports.
VALUING A TIMBER HARVEST CONTRACT AS A HIGH‐DIMENSIONAL AMERICAN CALL OPTION VIA LEAST‐SQUARES MONTE CARLO SIMULATION
Authors: MEI BIN , CLUTTER MICHAEL L.
Published: July 2012

Abstract Industrial timberland ownership in the United States has shifted substantially in the last 20 years. Having sold their fee‐owned timberlands, forest products companies relied heavily on the open market for raw timber. To reduce their exposure to market risks, however, forest products companies have been using a number of supply chain instruments, such as timber harvest contracts. As these vehicles become increasingly important to the forest industry, it is necessary and important to determine their economic values. In this study, we treated a 3‐year timber harvest contract on a 30‐year‐old loblolly pine plantation as a high‐dimensional American call option and calculated its value by the least‐squares Monte Carlo simulation technique. The estimated values of such a contract ranged from $1,693/ac to $1,984/ac under two timber price assumptions. With reasonable starting timber prices and strike price in the simulation, random timber prices led to higher contract values. Results from this study can help private landowners, timber brokers, and forest products companies better manage their business risks.
The effect of palatal dysfunction on measures of ventilation and gas exchange in Thoroughbred racehorses during high intensity exercise
Authors: Allen K. , Franklin S.
Published: July 2012

Reason for performing study:The effect of palatal instability (PI) on measures of ventilation and gas exchange is not well understood.

Objectives:To assess to what degree different severities of naturally occurring palatal dysfunction affect ventilation and gas exchange during strenuous exercise.

Methods:A retrospective study was performed using data collected from 40 Thoroughbred racehorses diagnosed with naturally occurring dynamic palatal dysfunction during high speed treadmill exercise. Upper airway videoendoscopic recordings were made concurrently with measurements of ventilation and gas exchange. Three categories of soft palate dysfunction were formed: mild palatal instability; moderate to severe palatal instability; and dorsal displacement of the soft palate (DDSP). Minute ventilation, tidal volume, breathing frequency, end‐tidal carbon dioxide and oxygen concentrations, oxygen consumption and carbon dioxide production were calculated during the last 10 s of the exercise test, when airway obstruction was at its worst.

Results:There was a trend for minute ventilation, tidal volume, oxygen consumption and carbon dioxide production to decrease with increasing degree of palatal dysfunction, although statistically significant differences were only seen with DDSP. End‐tidal carbon dioxide increased and end‐tidal oxygen decreased with increasing obstruction, with both parameters showing significant differences between mild PI and moderate to severe PI.

Conclusions:The results suggest that PI has a negative effect on certain respiratory parameters, although this is not as great as that associated with DDSP.

Potential relevance:Palatal instability may be detrimental to athletic performance even when progression to DDSP does not occur.
Asymptotic representations and Drinfeld rational fractions
Authors: Hernandez David , Jimbo Michio
Published: July 2012

We introduce and study a category of representations of the Borel algebra associated with a quantum loop algebra of non-twisted type. We construct fundamental representations for this category as a limit of the Kirillov–Reshetikhin modules over the quantum loop algebra and establish explicit formulas for their characters. We prove that general simple modules in this category are classified by n-tuples of rational functions in one variable which are regular and non-zero at the origin but may have a zero or a pole at infinity.
Derived splinters in positive characteristic
Authors: Bhatt Bhargav
Published: July 2012

This paper introduces the notion of a derived splinter. Roughly speaking, a scheme is a derived splinter if it splits off from the coherent cohomology of any proper cover. Over a field of characteristic 0, this condition characterises rational singularities, as suggested by the work of Kovács. Our main theorem asserts that over a field of characteristic p, derived splinters are the same as (underived) splinters, i.e. schemes that split off from any finite cover. Using this result, we answer some questions of Karen Smith concerning the extension of Serre/Kodaira-type vanishing results beyond the class of ample line bundles in positive characteristic; these are purely projective geometric statements independent of singularity considerations. In fact, we can prove ‘up to finite cover’ analogues in characteristic p of many vanishing theorems known in characteristic 0. All these results fit naturally in the study of F-singularities, and are motivated by a desire to understand the direct summand conjecture.
Preinspiratory calcium rise in putative pre‐Bötzinger complex astrocytes
Authors: Okada Yasumasa , Sasaki Takuya , Oku Yoshitaka , Takahashi Naoya , Seki Megumi , Ujita Sakiko , Tanaka Kenji F. , Matsuki Norio , Ikegaya Yuji
Published: July 2012

Key points

Autonomic respiratory rhythm is essential to maintain lives and is generated in the lower brainstem. The ventrolateral medullary region, called the pre‐Bötzinger complex (preBötC), is the kernel for respiratory rhythm generation. Despite previous extensive studies focusing on neurons, the mechanism of how respiratory rhythm is generated has not been fully understood.

Here we show that non‐neuronal glial cells (a subset of putative astrocytes) in the preBötC are periodically activated preceding inspiratory neuronal activity, periodic activity of putative astrocytes persists during blockade of neuronal activity, and stimulation of astrocytes in the preBötC induces inspiratory neuronal firings.

These findings together with the previous report that blockade of astrocytic metabolism abolishes inspiratory neural output suggest that astrocytes are functionally involved in respiratory rhythm generation.

These results will help us better understand how respiratory rhythm is generated and how respiratory output is disturbed in various pathological conditions.

Abstract  The neural inspiratory activity originates from a ventrolateral medullary region called the pre‐Bötzinger complex (preBötC), yet the mechanism underlying respiratory rhythmogenesis is not completely understood. Recently, the role of not only neurons but astrocytes in the central respiratory control has attracted considerable attention. Here we report our discovery that an intracellular calcium rise in a subset of putative astrocytes precedes inspiratory neuronal firing in rhythmically active slices. Functional calcium imaging from hundreds of preBötC cells revealed that a subset of putative astrocytes exhibited rhythmic calcium elevations preceding inspiratory neuronal activity with a time lag of approximately 2 s. These preinspiratory putative astrocytes maintained their rhythmic activities even during the blockade of neuronal activity with tetrodotoxin, whereas the rhythm frequency was lowered and the intercellular phases of these rhythms were decoupled. In addition, optogenetic stimulation of preBötC putative astrocytes induced firing of inspiratory neurons. These findings raise the possibility that astrocytes in the preBötC are actively involved in respiratory rhythm generation in rhythmically active slices.
Regulation of hippocampus‐dependent memory by the zinc finger protein Zbtb20 in mature CA1 neurons
Authors: Ren Anjing , Zhang Huan , Xie Zhifang , Ma Xianhua , Ji Wenli , He David Z.Z. , Yuan Wenjun , Ding Yu‐Qiang , Zhang Xiao‐Hui , Zhang Weiping J.
Published: July 2012

Key points

Zinc finger and BTB domain‐containing protein 20 (Zbtb20) plays a critical role in hippocampal development.

In the present study, we generated mutant mice in which Zbtb20 knockout was restricted to mature CA1 pyramidal cells of the hippocampus.

Conditionally deleting Zbtb20 specifically in mature CA1 pyramidal neurons impaired LTP and memory.

We found that Zbtb20 controls memory formation and synaptic plasticity by regulating NMDAR activity, and activation of ERK and CREB.

Abstract  The mammalian hippocampus harbours neural circuitry that is crucial for associative learning and memory. The mechanisms that underlie the development and regulation of this complex circuitry are not fully understood. Our previous study established an essential role for the zinc finger protein Zbtb20 in the specification of CA1 field identity in the developing hippocampus. Here, we show that conditionally deleting Zbtb20 specifically in mature CA1 pyramidal neurons impaired hippocampus‐dependent memory formation, without affecting hippocampal architecture or the survival, identity and basal excitatory synaptic activity of CA1 pyramidal neurons. We demonstrate that mature CA1‐specific Zbtb20 knockout mice exhibited reductions in long‐term potentiation (LTP) and NMDA receptor (NMDAR)‐mediated excitatory post‐synaptic currents. Furthermore, we show that activity‐induced phosphorylation of ERK and CREB is impaired in the hippocampal CA1 of Zbtb20 mutant mice. Collectively, these results indicate that Zbtb20 in mature CA1 plays an important role in LTP and memory by regulating NMDAR activity, and activation of ERK and CREB.
Production and Enhancement of Hydrogen From Water: A Review
Authors: Shahid M. , Bidin Noriah , Mat Yacoob , ullah M. Inayat
Published: July 2012

The production and escalation of hydrogen on a large scale is a goal toward the upheaval of green and cheap energy. During the last decades, many methods have been espoused to produce more hydrogen fuel. Right now hydrogen is hauled out from different sources, such as oil, coal, natural gas, water, etc. In case of water, the hydrogen is produced by different methods such as electrolysis, photosplitting, photoionization, photocatalysis, product analysis methods, etc. This review paper thrashes out the assessment of these assorted methods of hydrogen production from water.
Nonlinear Train-Bridge Lateral Interaction Using a Simplified Wheel-Rail Contact Method Within a Finite Element Framework
Authors: Antolín Pablo , Goicolea Jose M. , Oliva Javier , Astiz Miguel A.
Published: July 2012

The evaluation of running safety of railway vehicles on viaducts requires the study of lateral dynamics for the coupled vehicle-bridge system. This includes the structural deformation of the bridge, the vehicle multibody dynamics, and the consideration of wheel to rail contact. In this work, a fully nonlinear coupled method for such study is presented. The model is developed in a modular way using finite element models for the structure and multibody dynamics models for the vehicles in an absolute reference, and implemented within an existing finite element commercial code. A key feature is the consideration of the kinematics and dynamics of nonlinear wheel to rail interface, considering elastic-frictional contact. This contact is based on a global geometric constraint between wheelset and track and tangential forces at local level of each contact point. Some elementary applications are presented for the behavior of the model for stable and unstable hunting motion when subjected to transient lateral loads such as a wind gust. These results show the relevance of considering nonlinear effects and in particular wheel to flange contact.
Numerical Procedure for Dynamic Simulation of Two-Point Wheel/Rail Contact and Flange Climb Derailment of Railroad Vehicles
Authors: Yamashita Shunpei , Sugiyama Hiroyuki
Published: July 2012

In this investigation, a numerical procedure for wheel/rail contact problems in the analysis of curve negotiation of railroad vehicles is developed using constraint/elastic contact approach. In particular, this work focuses on the flange contact detection algorithm using the two-point look-up contact table and the switching algorithm from the elastic to constraint contact for the flange climb simulation. The two-point look-up contact table is used for the contact search of the second point of contact modeled using the elastic contact, while the constraint contact is used for the first point of contact on the wheel tread. Furthermore, in the flange climb simulation using the constraint contact formulation, loss of a tread contact modeled using the constraint contact occurs. Therefore, the elastic contact used for modeling the flange contact in the two-point contact state needs to be switched to the constraint contact as soon as loss of the tread contact occurs. For this reason, if the Lagrange multiplier associated with the contact constraint becomes greater than or equal to zero, the elastic contact used for the flange is switched to the constraint contact. The computational algorithm for the proposed switching algorithm is also presented. Several numerical examples are presented in order to demonstrate the use of the numerical procedure developed in this investigation for modeling the two-point tread/flange contact as well as the flange climb behavior. Numerical results are in good agreement with those of the existing fully elastic contact formulation. Furthermore, it is shown that significant reduction in CPU time is achieved using the numerical procedure developed in this investigation.
Acoustic communication in deep water exploiting multiple beams with a horizontal array
Authors: Song H. C.
Published: July 2012

A recent experiment showed that coherent long-range acoustic communication (200–300 Hz) is feasible in deep water over a ∼550-km range between a source and a horizontal towed array (∼100 m aperture). The low input signal-to-noise ratio (SNR) (e.g., −10 dB) at an element level required conventional beamforming to enhance the SNR of the communication signals for subsequent channel equalization and decoding. This paper demonstrates that with a larger aperture (∼200 m), multiple adjacent beams can be exploited to further improve the communication performance, achieving an almost error-free data rate of 100 bits/s for QPSK modulation at ∼550 km range.
Ambient habitat noise and vibration at the Georgia Aquarium
Authors: Scheifele P. M. , Johnson M. T. , Kretschmer L. , Clark J. G. , Kemper D. , Potty G.
Published: July 2012

Underwater and in-air noise evaluations were completed in performance pool systems at Georgia Aquarium under normal operating conditions and with performance sound tracks playing. Ambient sound pressure levels at in-pool locations, with corresponding vibration measures from life support system (LSS) pumps, were measured in operating configurations, from shut down to full operation. Results indicate noise levels in the low frequency ranges below 100 Hz were the highest produced by the LSS relative to species hearing thresholds. The LSS had an acoustic impact of about 10 dB at frequencies up to 700 Hz, with a 20 dB re 1 μPa impact above 1000 Hz.
Differential cue weighting in perception and production of consonant voicing
Authors: Shultz Amanda A. , Francis Alexander L. , Llanos Fernando
Published: July 2012

This study examines English speakers’ relative weighting of two voicing cues in production and perception. Participants repeated words differing in initial consonant voicing ([b] or [p]) and labeled synthesized tokens ranging between [ba] and [pa] orthogonally according to voice onset time (VOT) and onset f0. Discriminant function analysis and logistic regression were used to calculate individuals’ relative weighting of each cue. Production results showed a significant negative correlation of VOT and onset f0, while perception results showed a trend toward a positive correlation. No significant correlations were found across perception and production, suggesting a complex relationship between the two domains.
A follow-up investigation into the mechanisms that underlie improved recognition of dysarthric speech
Authors: Borrie Stephanie A. , McAuliffe Megan J. , Liss Julie M. , O’Beirne Greg A. , Anderson Tim J.
Published: July 2012

Differences in perceptual strategies for lexical segmentation of moderate hypokinetic dysarthric speech, apparently related to the conditions of the familiarization procedure, have been previously reported [Borrie et al., Language and Cognitive Processes (2012)]. The current follow-up investigation examined whether this difference was also observed when familiarization stimuli highlighted syllabic strength contrast cues. Forty listeners completed an identical transcription task following familiarization with dysarthric phrases presented under either passive or explicit learning conditions. Lexical boundary error patterns revealed that syllabic strength cues were exploited in both familiarization conditions. Comparisons with data previously reported afford further insight into perceptual learning of dysarthric speech.
Dissecting Wnt/Fz Interaction
Authors: Vinson Valda K.
Published: July 2012

The structure of the morphogen Wnt bound to its receptor provides a basis for understanding Wnt’s functional pleiotropy.
Some Like It Hot
Authors: Wong Wei
Published: July 2012

An anion channel is a heat sensor in nociceptive neurons.
Reconstructing the TCR
Authors: Andrianantoandro Ernesto
Published: July 2012

Engineering nonimmune cells with components of the T cell receptor signaling system enables the interaction with antigen-presenting cells to initiate T cell receptor activation.
Characterization of a Conjugate between Rose Bengal and Chitosan for Targeted Antibiofilm and Tissue Stabilization Effects as a Potential Treatment of Infected Dentin
Authors: Shrestha Annie , Hamblin Michael R. , Kishen Anil
Published: July 2012

Bacterial biofilms and dentin structural changes are some of the major challenges in the management of infected dentin tissue. This study characterized a photosensitizer-conjugated chitosan with enhanced photodynamic efficacy against dental biofilms, as well as the ability to reinforce the postinfected dentin matrix in order to improve its mechanical and chemical stability. Rose Bengal-conjugated chitosan (CSRB) was synthesized using a chemical cross-linking method and characterized for photophysical, photobiological, and cytotoxicity properties. Its potential as an antibacterial and matrix-reinforcing agent on dentin collagen was also evaluated.
Enterococcus faecalis
as planktonic and
in vitro
biofilms was treated with CSRB and photodynamically activated with 5 to 60 J/cm
2
green light. Dentin collagen was used for the CSRB cross-linking experiments and evaluated for chemical changes, resistance to enzymatic degradation, and mechanical properties. CSRB was a photosensitizer with efficient singlet oxygen yield.
In vitro
photoactivation gave higher fibroblast cell survival than did RB alone. CSRB showed significant antibiofilm photoinactivation (
P
< 0.01). The CSRB-cross-linked dentin collagen showed higher resistance to collagenase degradation and superior mechanical properties (
P
< 0.05). In summary, the photoactivated CSRB particles synthesized in this study may be a synergistic multifunctional treatment approach with lower cytotoxicity and effective antibiofilm activity as well as the ability to reinforce the dentin collagen to enhance resistance to degradation and improve mechanical properties. This may be a targeted treatment strategy to deal with infected dentin hard tissues in a clinical scenario, where both disinfection and structural integrity need to be addressed concomitantly.
FimA, FimF, and FimH Are Necessary for Assembly of Type 1 Fimbriae on Salmonella enterica Serovar Typhimurium
Authors: Zeiner Sarah A. , Dwyer Brett E. , Clegg Steven
Published: July 2012

Salmonella enterica
serovar Typhimurium is a Gram-negative member of the family
Enterobacteriaceae
and is a common cause of bacterial food poisoning in humans. The fimbrial appendages are found on the surface of many enteric bacteria and enable the bacteria to bind to eukaryotic cells.
S
. Typhimurium type 1 fimbriae are characterized by mannose-sensitive hemagglutination and are assembled via the chaperone/usher pathway.
S
. Typhimurium type 1 fimbrial proteins are encoded by the
fim
gene cluster (
fimAICDHFZYW
), with
fimAICDHF
expressed as a single transcriptional unit. The structural components of the fimbriae are FimA (major subunit), FimI, FimH (adhesin), and FimF (adaptor). In order to determine which components are required for fimbrial formation in
S
. Typhimurium, mutations in
fimA
,
fimI
,
fimH
, and
fimF
were constructed and examined for their ability to produce surface-assembled fimbriae.
S
. Typhimurium SL1344Δ
fimA
, -Δ
fimH
, and -Δ
fimF
mutants were unable to assemble fimbriae, indicating that these genes are necessary for fimbrial production in
S
. Typhimurium. However, SL1344Δ
fimI
was able to assemble fimbriae. In
Escherichia coli
type 1 and Pap fimbriae, at least two adaptors are expressed in addition to the adhesins. However,
E. coli
type 1 and Pap fimbriae have been reported to be able to assemble fimbriae in the absence of these proteins. These results suggest differences between the
S
. Typhimurium type 1 fimbrial system and the
E. coli
type 1 and Pap fimbrial systems.
Diarrhea and Colitis in Mice Require the Salmonella Pathogenicity Island 2-Encoded Secretion Function but Not SifA or Spv Effectors
Authors: Fierer Joshua , Okamoto Sharon , Banerjee Ananya , Guiney Donald G.
Published: July 2012

We investigated the roles of
Salmonella
pathogenicity island 2 (SPI-2) and two SPI-2 effectors in
Salmonella
colitis and diarrhea in genetically resistant BALB/c.D2

Slc11a1

congenic mice with the wild-type Nramp1 locus. Wild-type
Salmonella enterica
serovar Typhimurium 14028s caused a pan-colitis, and the infected mice developed frank diarrhea with a doubling of the fecal water content. An
ssaV
mutant caused only a 26% increase in fecal water content, without producing the pathological changes of colitis, and it did not cause weight loss over a 1-week period of observation. However, two SPI-2 effector mutants, the
spvB
and
sifA
mutants, and a double
spvB sifA
mutant caused diarrhea and colitis, even though the
sifA
mutant was sensitive to killing by bone marrow-derived macrophages from BALB/c.D2 mice and was severely impaired in extraintestinal growth but not in growth in the cecum. These results demonstrate that systemic
S. enterica
infection and diarrhea/colitis are distinct pathogenic processes and that only the former requires
spvB
and
sifA
.
The Toxoplasma gondii Peptide AS15 Elicits CD4 T Cells That Can Control Parasite Burden
Authors: Grover Harshita Satija , Blanchard Nicolas , Gonzalez Federico , Chan Shiao , Robey Ellen A. , Shastri Nilabh
Published: July 2012

The apicomplexan parasiteToxoplasma gondiican cause severe disease in immunocompromised individuals. Previous studies in mice have focused largely on CD8+T cells, and the role of CD4 T cells is relatively unexplored. Here, we show that immunization of the C57BL/6 strain of mice, in which the immunodominant CD8 T cell response to the parasite dense-granule protein GRA6 cannot be generated, leads to a prominent CD4 T cell response. To identify the CD4 T cell-stimulating antigens, we generated aT. gondii-specific,lacZ-inducible, CD4 T cell hybridoma and used it as a probe to screen aT. gondiicDNA library. We isolated a cDNA encoding a protein of unknown function that we call CD4Ag28m and identified the minimal peptide, AS15, which was presented by major histocompatibility complex (MHC) class II molecules to the CD4 T cells. Immunization of mice with the AS15 peptide provided significant protection against subsequent parasite challenge, resulting in a lower parasite burden in the brain. Our findings identify the first CD4 T cell-stimulating peptide that can confer protection against toxoplasmosis and provide an important tool for the study of CD4 T cell responses and the design of effective vaccines against the parasite.
HcpR of Porphyromonas gingivalis Is Required for Growth under Nitrosative Stress and Survival within Host Cells
Authors: Lewis Janina P. , Yanamandra Sai S. , Anaya-Bergman Cecilia
Published: July 2012

Although the Gram-negative, anaerobic periodontopathogen
Porphyromonas gingivalis
must withstand nitrosative stress, which is particularly high in the oral cavity, the mechanisms allowing for protection against such stress are not known in this organism. In this study, microarray analysis of
P. gingivalis
transcriptional response to nitrite and nitric oxide showed drastic upregulation of the PG0893 gene coding for hybrid cluster protein (Hcp), which is a putative hydroxylamine reductase. Although regulation of
hcp
has been shown to be OxyR dependent in
Escherichia coli
, here we show that in
P. gingivalis
its expression is dependent on the Fnr-like regulator designated HcpR. Growth of the isogenic mutant V2807, containing an
ermF-ermAM
insertion within the
hcpR
(PG1053) gene, was significantly reduced in the presence of nitrite (
P
< 0.002) and nitric oxide-generating nitrosoglutathione (GSNO) (
P
< 0.001), compared to that of the wild-type W83 strain. Furthermore, the upregulation of PG0893 (
hcp
) was abrogated in V2807 exposed to nitrosative stress. In addition, recombinant HcpR bound DNA containing the
hcp
promoter sequence, and the binding was hemin dependent. Finally, V2807 was not able to survive with host cells, demonstrating that HcpR plays an important role in
P. gingivalis
virulence. This work gives insight into the molecular mechanisms of protection against nitrosative stress in
P. gingivalis
and shows that the regulatory mechanisms differ from those in
E. coli
.
Infection with Mycobacterium avium subsp. paratuberculosis Results in Rapid Interleukin-1β Release and Macrophage Transepithelial Migration
Authors: Lamont Elise A. , O'Grady Scott M. , Davis William C. , Eckstein Torsten , Sreevatsan Srinand
Published: July 2012

Pathogen processing by the intestinal epithelium involves a dynamic innate immune response initiated by pathogen-epithelial cell cross talk. Interactions between epithelium andMycobacterium aviumsubsp.paratuberculosishave not been intensively studied, and it is currently unknown how the bacterium-epithelial cell cross talk contributes to the course of infection. We hypothesized thatM. aviumsubsp.paratuberculosisharnesses host responses to recruit macrophages to the site of infection to ensure its survival and dissemination. We investigated macrophage recruitment in response toM. aviumsubsp.paratuberculosisusing a MAC-T bovine macrophage coculture system. We show thatM. aviumsubsp.paratuberculosisinfection led to phagosome acidification within bovine epithelial (MAC-T) cells as early as 10 min, which resulted in upregulation of interleukin-1β (IL-1β) at transcript and protein levels. Within 10 min of infection, macrophages were recruited to the apical side of MAC-T cells. Inhibition of phagosome acidification or IL-1β abrogated this response, while MCP-1/CCL-2 blocking had no effect. IL-1β processing was dependent upon Ca2+uptake from the extracellular medium and intracellular Ca2+oscillations, as determined by EGTA and BAPTA-AM [1,2-bis(2-aminophenoxy) ethane-N,N,N′,N′-tetraacetic acid tetrakis (acetoxymethyl ester)] treatments. Thus,M. aviumsubsp.paratuberculosisis an opportunist that takes advantage of extracellular Ca2+-dependent phagosome acidification and IL-1β processing in order to efficiently transverse the epithelium and enter its niche—the macrophage.
Gastrointestinal stromal tumour originating from the hepatic falciform ligament
Authors: Abedalthagafi Malak
Published: July 2012

Primary extraluminal gastrointestinal stromal tumours (GISTs) originating from outside of the GI tract are not uncommon. However, none have been reported to arise from the falciform ligament of the liver. The natural history and prognostic indicators for primary GISTs, while still unclear, have been under much investigation, and some promising therapeutic options have surfaced, including surgical removal and adjuvant chemotherapy with imatinib.
High-output heart failure in a newborn
Authors: Mascarenhas Maria Inês , Moniz Marta , Ferreira Sofia , Goulão Augusto , Barroso Rosalina
Published: July 2012

High-output cardiac failure is rare in newborns. Emergent diagnosis and management of this pathology is crucial. We report the case of a child, currently 12-months old; obstetric background is non-contributory. Clinic observation on D1 was normal except for the presence of a systolic cardiac murmur; cardiological evaluation revealed mild ventricular dysfunction of the right ventricle. On the third day of life, she developed cardiac failure with gallop rhythm, hepatomegaly and a murmur in the anterior fontanel; an echocardiogram confirmed clinic aggravation with biventricular dysfunction and right cavities and superior vena cava dilatation. The cranial MRI confirmed the presence of a pial arteriovenous malformation (AVM) involving the anterior and middle cerebral arteries with an associated fronto-parietal ischaemic lesion. The infant underwent embolisations of AVM with successful flow reduction and cardiac failure improvement. The multidisciplinary follow-up showed no cardiac dysfunction or permanent lesions but confirmed a severe psycho-motor delay and left hemiparesia.
Atypical presentation of Boerhaave's syndrome
Authors: Gupta Rakesh Kumar , Sah Panna Lal , Sah Suresh , Sapkota Sudeep
Published: July 2012

Boerhaave's syndrome is the rare and often fatal condition of spontaneous oesophageal rupture. When present with atypical symptoms, diagnosis is frequently late, which contributes to the high morbidity and mortality. The authors describe a unique case of a 50-year-old man presented with atypical Boerhaave's syndrome, in which the diagnosis was made several days following presentation by observing a large pleural effusion that had evolved rapidly on chest radiographs. He was managed without thoracotomy. Although survival has been reported with non-operative management of contained oesophageal perforations, to our knowledge, this is the rare case report of surviving Boerhaave's syndrome with free pleural rupture, without thoracotomy.
Physical activity/fitness peaks during perimenopause and BMI change patterns are not associated with baseline activity/fitness in women: a longitudinal study with a median 7-year follow-up
Authors: Sui Xuemei , Zhang Jiajia , Lee Duck-chul , Church Timothy S , Lu Wenbin , Liu Junxiu , Blair Steven N
Published: July 2012

Objective

To assess the age-associated longitudinal trends in cardiorespiratory fitness (CRF), leisure-time physical activity (PA), and body mass index (BMI) across the lifespan in a cohort of adult women.

Methods

The sample included 1467 women from the Aerobics Center Longitudinal Study who were 30–79 years old at baseline and had 3–22 health examinations between 1971 and 2006. CRF was quantified by maximal Balke treadmill exercise tests. The total metabolic equivalent-minutes/week of self-reported PA and measured BMI (kg/m2) were calculated.

Results

The overall pattern of CRF decreased over time. After age 60 years, fitness level tended to decline rapidly. Women at age 50 had the highest PA level, which decreased after age 50 and plateaued at age 60. The overall pattern of BMI increased with age. However, after age 60 years the rate of increase in BMI became much slower. Adjusting for smoking, health status, and the individual exposures of CRF, PA and BMI did not influence the observed associations. Women who did not meet current PA recommendation or those who were low fit at baseline had a higher BMI throughout adulthood than their more active or fit peers, but the trajectory of BMI was unassociated with baseline activity or fitness levels.

Conclusion

We concluded that the age-related longitudinal patterns in physical activity and fitness are not linear. Baseline activity and fitness levels are associated with BMI status during adulthood, but do not affect BMI change trajectory.
Heat illness surveillance in schoolboys participating in physical education class in tropical climate: an analytical prospective descriptive study
Authors: Somboonwong Juraiporn , Sanguanrungsirikul Sompol , Pitayanon Chatchatchai
Published: July 2012

Objectives

This study aimed to determine thermoregulatory and cardiovascular responses as well as the occurrence of heat illness in children exercising outdoors in physical education class under hot and humid climate. Little information regarding this issue under real-life situation is available, especially in the Southeast Asia.

Design

Analytical, prospective descriptive study.

Setting

A primary school in Bangkok, Thailand.

Participants

A total of 457 schoolboys (aged 5.5–12 years) were observed while exercising outdoors during their physical education classes throughout the academic year of 2009, including semester 1 (between July and September 2009) and semester 2 (between November 2009 and February 2010).

Primary and secondary outcome measures

Primary outcome measure was tympanic temperature. Secondary outcome measures included blood pressure, heart rate, hydration status and the occurrence of heat-related illness.

Results

Outdoor physical activity consisted of skill practice (duration 24.11±11.04 min, intensity <3 metabolic equivalent of tasks) and playing sports (duration 11.48±5.53 min, intensity 2.6–8.8 metabolic equivalent of tasks). After exercise, tympanic temperature increased by 0.66±0.41°C. There were 20 (4.4%) students whose ear temperature exceeded 38°C, 18 of whom did not consume water. The RR of increasing body temperature up to 38°C in overweight students was 2.1-fold higher than normal-weight students. The per cent change in mean arterial pressure and heart rate increased by 20.16±15.34% and 23.94±19.78%, respectively. Sweat and dehydration rates were 391.16±186.75 ml/h and 0.63±0.26%, respectively. No evidence of heat illness was found. Wet bulb globe temperatures of semesters 1 and 2 were 29.95±1.87°C and 28.32±2.39°C, respectively.

Conclusions

There is an increased risk for heat illness during outdoor activities in physical education class in primary school children, especially those who are overweight and have poor hydration status.
A case–control study on risk factors associated with death in pregnant women with severe pandemic H1N1 infection
Authors: Li Furong , Chen Guoping , Wang Jianjun , Liu Hong , Wu Jiabing
Published: July 2012

Objectives

To describe the risk factors associated with death in pregnant women with severe pandemic H1N1 infection.

Design

Case–control study.

Setting

Anhui, China.

Participants

A total of 46 pregnant women with severe pandemic H1N1 infection were studied during June 2009–April 2011.

Primary and secondary outcome measures

All the cases were confirmed by the clinicians and epidemiologists together based on the positive laboratory result.

Results

Of the seven pregnant women who died of the pandemic H1N1 infection, five (70%) cases were in their third trimester. Twenty-nine (63%) cases from the surviving group were admitted to hospital within 3 days after the onset of symptoms, while only one (2%) case from the death group took the earliest admission 2 days after the onset. There was a significant difference on how soon to be admitted between the death and the surviving groups (OR 0.09, 95% CI 0.01 to 0.68). The median time of administrating corticosteroids was 5 days after the onset in the death group and 3 days in the surviving group showing no significant difference between them (p=0.056).

Conclusions

For the pregnant women with severe p(H1N1) infection, the risk factors associated with death were as follows: the delay of antiviral treatment and being in the third trimester. The corticosteroids therapy appeared to have no effects on preventing the cases from death.
Sedentary behaviour and life expectancy in the USA: a cause-deleted life table analysis
Authors: Katzmarzyk Peter T , Lee I-Min
Published: July 2012

Objectives

To determine the impact of sitting and television viewing on life expectancy in the USA.

Design

Prevalence-based cause-deleted life table analysis.

Setting

Summary RRs of all-cause mortality associated with sitting and television viewing were obtained from a meta-analysis of available prospective cohort studies. Prevalences of sitting and television viewing were obtained from the US National Health and Nutrition Examination Survey.

Primary outcome measure

Life expectancy at birth.

Results

The estimated gains in life expectancy in the US population were 2.00 years for reducing excessive sitting to <3 h/day and a gain of 1.38 years from reducing excessive television viewing to <2 h/day. The lower and upper limits from a sensitivity analysis that involved simultaneously varying the estimates of RR (using the upper and lower bounds of the 95% CI) and the prevalence of television viewing (±20%) were 1.39 and 2.69 years for sitting and 0.48 and 2.51 years for television viewing, respectively.

Conclusion

Reducing sedentary behaviours such as sitting and television viewing may have the potential to increase life expectancy in the USA.
Education-to-job mismatch and the risk of work injury
Authors: Premji Stephanie , Smith Peter M
Published: July 2012

Objectives

To examine the association between education-to-job mismatch and work injury.

Methods

Cross-sectional data from the 2003 and 2005 Canadian Community Health Surveys (n=63 462) were used to examine the relationship between having an educational level that is incongruent with occupational skills requirements and the risk of sustaining a work injury requiring medical attention or a work-related repetitive movement injury (RMI). The effect on injury of the interaction of overeducation with recent immigrant status was also examined. Models were stratified by sex and adjusted for possible confounders. Occupational physical demands were conceptualised as a potential mediating variable.

Results

After adjustment for covariates, over-education was associated with work injury and RMI for both sexes. Adjustment for occupational demands attenuated the impact on work injury but did not eliminate the effect on RMI among men. The interaction of over-education and recent immigrant status resulted among men in a fourfold increase in the odds of work injury compared with non-recent immigrants who were not over-educated. After adjustment for occupational demands, over-educated recent immigrant men still had more than a twofold increase in the odds of injury.

Conclusions

The risk of sustaining a work injury is higher among those whose education exceeds that of job requirements. These findings highlight the need to address barriers to suitable employment, particularly among recent immigrants.