bluuebunny/crossref_metadata_2025_split huggingface dataset:
Latino and Latina Adolescents' Help‐seeking Behaviors and Attitudes Regarding Suicide Compared to Peers with Recent Suicidal Ideation
Authors: De Luca Susan , Schmeelk‐Cone Karen , Wyman Peter 
Published: January 2015

Although Latinas have consistently reported higher rates of suicidal behavior for the past 20 years (CDC, 1996), there is a dearth of information regarding their help‐seeking attitudes and behaviors when dealing with distress and suicide. Associations between adolescents' ideation and help‐seeking from adults were different for non‐Hispanic Whites and Latinos from 14 high schools (N = 4,983). Among females, ideators and Latinas reported lower levels of help‐seeking attitudes than nonideators and non‐Hispanic Whites. Males showed interaction effects of ideation by race/ethnicity on help‐seeking. Within sex by race/ethnicity, differences showed that while non‐Hispanic White students reported consistent differences between suicidal ideation and no reported suicidal ideation, Latinos were more similar between these groups, particularly with having support from friends and family to seek help from adults. Research should clarify how culture contributes to decreased help‐seeking norms among those with suicidal ideation.
Risk factors for pre‐ and post‐engraftment bloodstream infections after allogeneic hematopoietic stem cell transplantation
Authors: Kikuchi M. , Akahoshi Y. , Nakano H. , Ugai T. , Wada H. , Yamasaki R. , Sakamoto K. , Kawamura K. , Ishihara Y. , Sato M. , Ashizawa M. , Terasako‐Saito K. , Kimura S. , Yamazaki R. , Kanda J. , Kako S. , Nishida J. , Kanda Y. 
Published: January 2015

AbstractBackgroundBloodstream infections (BSI) are frequently observed after allogeneic hematopoietic stem cell transplant (HSCT), and could cause morbidity and mortality.MethodsWe retrospectively evaluated the incidence, characteristics of, and risk factors for BSI at both pre‐ and post‐engraftment in 209 adult HSCT patients at our institute between June 2006 and December 2013. The median age at transplantation was 45 years (range, 15–65). A total of 122 patients received bone marrow, 68 received peripheral blood stem cells, and 19 received umbilical cord blood.ResultsThe cumulative incidences of pre‐ and post‐engraftment BSI were 38.9% and 17.2%, respectively. Nine patients had both pre‐ and post‐engraftment BSI. In the pre‐ and post‐engraftment periods, respectively, 67.4% and 84.1% of isolates were gram‐positive bacteria (GPB), 28.3% and 11.4% were gram‐negative bacteria (GNB), and 4.3% and 4.5% were fungi. Coagulase‐negative staphylococci were the most commonly isolated GPB, while Stenotrophomonas maltophilia and Pseudomonas aeruginosa were the most commonly isolated GNB. Pre‐engraftment BSI was associated with an increased risk of death. Overall survival at day 180 for patients with or without pre‐engraftment BSI was 70.0% and 82.7%, respectively (P = 0.02).ConclusionsRisk factors for BSI in the pre‐engraftment period were the interval between diagnosis and transplantation (261 days or more), engraftment failure, and high‐risk disease status at HSCT in a multivariate analysis. No significant risk factor for BSI in the post‐engraftment period was identified by a univariate analysis. These findings may be useful for deciding upon empiric antibacterial treatment for HSCT recipients.
Foreign Market Entry Under Incomplete Contracts
Authors: Seidel Tobias 
Published: January 2015

AbstractThis paper shows that incomplete contracts serve as a determinant of the mode of foreign market entry – that is exports versus foreign direct investment (FDI). When contracts between two agents within a firm are too costly to be written, the share of multinational firms may be higher or lower compared with a world without contractual frictions. The direction of change depends on the technologically required relative contribution of headquarter services in the joint production process. For example, in industries that use more inputs from the management unit as compared to inputs from a component supplier, the share of firms engaging in foreign direct investment is higher than under complete contracts. This effect may be so strong that the share of multinational firms increases in trade freeness.
Angiotensin II can directly induce mitochondrial dysfunction, decrease oxidative fibre number and induce atrophy in mouse hindlimb skeletal muscle
Authors: Kadoguchi Tomoyasu , Kinugawa Shintaro , Takada Shingo , Fukushima Arata , Furihata Takaaki , Homma Tsuneaki , Masaki Yoshihiro , Mizushima Wataru , Nishikawa Mikito , Takahashi Masashige , Yokota Takashi , Matsushima Shouji , Okita Koichi , Tsutsui Hiroyuki 
Published: January 2015

New findings

What is the central question of this study?
Does angiotensin II directly induce skeletal muscle abnormalities?

What is the main finding and its importance?
Angiotensin II induces skeletal muscle abnormalities and reduced exercise capacity. Mitochondrial dysfunction and a decreased number of oxidative fibres are manifest early, while muscle atrophy is seen later. Thus, angiotensin II may play an important role in the skeletal muscle abnormalities observed in a wide variety of diseases.

Skeletal muscle abnormalities, such as mitochondrial dysfunction, a decreased percentage of oxidative fibres and atrophy, are the main cause of reduced exercise capacity observed in ageing and various diseases, including heart failure. The renin–angiotensin system, particularly angiotensin II (Ang II), is activated in the skeletal muscle in these conditions. Here, we examined whether Ang II could directly induce these skeletal muscle abnormalities and investigated their time course. Angiotensin II (1000 ng kg−1 min−1) or vehicle was administered to male C57BL/6J mice (10–12 weeks of age) via subcutaneously implanted osmotic minipumps for 1 or 4 weeks. Angiotensin II significantly decreased body and hindlimb skeletal muscle weights compared with vehicle at 4 weeks. In parallel, muscle cross‐sectional area was also decreased in the skeletal muscle at 4 weeks. Muscle RING finger‐1 and atrogin‐1 were significantly increased in the skeletal muscle from mice treated with Ang II. In addition, cleaved caspase‐3 and terminal deoxynucleotidyl trasferase‐mediated dUTP nick‐positive nuclei were significantly increased in mice treated with Ang II at 1 and 4 weeks, respectively. Mitochondrial oxidative enzymes, such as citrate synthase, complex I and complex III activities were significantly decreased in the skeletal muscle from mice treated Ang II at 1 and 4 weeks. NAD(P)H oxidase‐derived superoxide production was increased. NADH staining revealed that type I fibres were decreased and type IIb fibres increased in mice treated with Ang II at 1 week. The work and running distance evaluated by a treadmill test were significantly decreased in mice treated with Ang II at 4 weeks. Thus, Ang II could directly induce the abnormalities in skeletal muscle function and structure.
Interactions between mitochondria and the transcription factor myocyte enhancer factor 2 (MEF2) regulate neuronal structural and functional plasticity and metaplasticity
Authors: Brusco Janaina , Haas Kurt 
Published: January 2015

AbstractThe classical view of mitochondria as housekeeping organelles acting in the background to simply maintain cellular energy demands has been challenged by mounting evidence of their direct and active participation in synaptic plasticity in neurons. Time‐lapse imaging has revealed that mitochondria are motile in dendrites, with their localization and fusion and fission events regulated by synaptic activity. The positioning of mitochondria directly influences function of nearby synapses through multiple pathways including control over local concentrations of ATP, Ca2+ and reactive oxygen species. Recent studies have also shown that mitochondrial protein cascades, classically associated with apoptosis, are involved in neural plasticity in healthy cells. These findings link mitochondria to the plasticity‐ and metaplasticity‐associated activity‐dependent transcription factor myocyte enhancer factor 2 (MEF2), further repositioning mitochondria as potential command centres for regulation of synaptic plasticity. Intriguingly, MEF2 and mitochondrial functions appear to be intricately intertwined, as MEF2 is a target of mitochondrial apoptotic caspases and, in turn, MEF2 regulates mitochondrial genome transcription essential for production of superoxidase and hydrogen peroxidase. Here, we review evidence supporting mitochondria as central organelles controlling the spatiotemporal expression of neuronal plasticity, and attempt to disentangle the MEF2–mitochondria relationship mediating these functions.
Protease‐activated receptors modulate excitability of murine colonic smooth muscles by differential effects on interstitial cells
Authors: Sung Tae Sik , Kim Heung Up , Kim Jeong Hwan , Lu Hongli , Sanders Kenton M. , Koh Sang Don 
Published: January 2015

Key points
Activation of protease‐activated receptors (PAR) regulates gastrointestinal (GI) motility but little is known about the cells and mechanisms in GI muscles responsible for PAR responses.
Using mouse cells, we found high levels of F2r and F2rl1 PAR‐encoding genes expressed in purified platelet‐derived growth factor α‐positive (PDGFRα+) cells in comparison to other cells in colonic muscles.
PAR1 and PAR2 agonists caused transient hyperpolarization and relaxation of colonic muscles, with relaxation responses followed by excitation.
The inhibitory phase was inhibited by apamin and mediated by activation of small conductance calcium‐activated potassium channels in PDGFRα+ cells.
The excitatory response resulted largely from activation of a chloride conductance in interstitial cells of Cajal; small amplitude inward currents were generated in smooth muscle cells by PAR activation, but these responses were too small to be resolved in intact muscles.
PAR receptor responses are integrated responses generated by cells of the smooth muscle, interstitial cells of Cajal and PDGFRα+ cells (SIP syncytium).
AbstractProtease‐activated receptors (PARs) are G protein‐coupled receptors activated by proteolytic cleavage at their amino termini by serine proteases. PAR activation contributes to the inflammatory response in the gastrointestinal (GI) tract and alters GI motility, but little is known about the specific cells within the tunica muscularis that express PARs and the mechanisms leading to contractile responses. Using real time PCR, we found PARs to be expressed in smooth muscle cells (SMCs), interstitial cells of Cajal (ICC) and platelet‐derived growth factor receptor α positive (PDGFRα+) cells. The latter cell‐type showed dominant expression of F2r (encodes PAR1) and F2rl1 (encodes PAR2). Contractile and intracellular electrical activities were measured to characterize the integrated responses to PAR activation in whole muscles. Cells were isolated and ICC and PDGFRα+ cells were identified by constitutive expression of fluorescent reporters. Thrombin (PAR1 agonist) and trypsin (PAR2 agonist) caused biphasic responses in colonic muscles: transient hyperpolarization and relaxation followed by repolarization and excitation. The inhibitory phase was blocked by apamin, revealing a distinct excitatory component. Patch clamp studies showed that the inhibitory response was mediated by activation of small conductance calcium‐activated K+ channels in PDGFRα+ cells, and the excitatory response was mediated by activation of a Cl− conductance in ICC. SMCs contributed little to PAR responses in colonic muscles. In summary, PARs regulate the excitability of colonic muscles; different conductances are activated in each cell type of the SMC–ICC–PDGFRα+ cell (SIP) syncytium. Motor responses to PAR agonists are integrated responses of the SIP syncytium.
The influence of sensory afferent input on local motor cortical excitatory circuitry in humans
Authors: Cash Robin F. H. , Isayama Reina , Gunraj Carolyn A. , Ni Zhen , Chen Robert 
Published: January 2015

Key points
In the human, sensorimotor integration can be investigated using combined sensory and transcranial magnetic stimulation (TMS).
Short latency afferent inhibition (SAI) refers to motor cortical inhibition 20–25ms after median nerve stimulation.
We investigated the influence of SAI on a local excitatory interneuronal motor cortical circuit known as short‐interval intracortical facilitation (SICF) and found that, contrary to expectations, SICF was facilitated in the presence of SAI (SICFSAI); this effect is specific to SICF since there was no effect in control conditions in which SICF was not elicited, and the facilitatory SICFSAI interaction increased with increasing strength of SICF or SAI.
The influence of sensory input on excitatory motor cortical circuitry was similar across different bodily regions, different circuits within motor cortex and across functional states, suggesting that this interaction may have general applicability in sensorimotor integration and motor control.
SAI and SICF were found to correlate between individuals in that those with high SAI were found to have high SICF, and this relationship was maintained when SICF was delivered in the presence of SAI, suggesting an intrinsic relationship between SAI and SICF; these findings are compatible with brain‐slice studies of sensorimotor circuitry and add to our understanding of sensorimotor integration.
AbstractIn human, sensorimotor integration can be investigated by combining sensory input and transcranial magnetic stimulation (TMS). Short latency afferent inhibition (SAI) refers to motor cortical inhibition 20–25 ms after median nerve stimulation. We investigated the interaction between SAI and short‐interval intracortical facilitation (SICF), an excitatory motor cortical circuit. Seven experiments were performed. Contrary to expectations, SICF was facilitated in the presence of SAI (SICFSAI). This effect is specific to SICF since there was no effect at SICF trough 1 when SICF was absent. Furthermore, the facilitatory SICFSAI interaction increased with stronger SICF or SAI. SAI and SICF correlated between individuals, and this relationship was maintained when SICF was delivered in the presence of SAI, suggesting an intrinsic relationship between SAI and SICF in sensorimotor integration. The interaction was present at rest and during muscle contraction, had a broad degree of somatotopic influence and was present in different interneuronal SICF circuits induced by posterior–anterior and anterior–posterior current directions. Our results are compatible with the finding that projections from sensory to motor cortex terminate in both superficial layers where late indirect (I‐) waves are thought to originate, as well as deeper layers with more direct effect on pyramidal output. This interaction is likely to be relevant to sensorimotor integration and motor control.
Ultralow dose computed tomography attenuation correction for pediatric PET CT using adaptive statistical iterative reconstruction
Authors: Brady Samuel L. , Shulkin Barry L. 
Published: January 2015

Purpose:To develop ultralow dose computed tomography (CT) attenuation correction (CTAC) acquisition protocols for pediatric positron emission tomography CT (PET CT).Methods:A GE Discovery 690 PET CT hybrid scanner was used to investigate the change to quantitative PET and CT measurements when operated at ultralow doses (10–35 mA s). CT quantitation: noise, low‐contrast resolution, and CT numbers for 11 tissue substitutes were analyzed in‐phantom. CT quantitation was analyzed to a reduction of 90% volume computed tomography dose index (0.39/3.64; mGy) from baseline. To minimize noise infiltration, 100% adaptive statistical iterative reconstruction (ASiR) was used for CT reconstruction. PET images were reconstructed with the lower‐dose CTAC iterations and analyzed for: maximum body weight standardized uptake value (SUVbw) of various diameter targets (range 8–37 mm), background uniformity, and spatial resolution. Radiation dose and CTAC noise magnitude were compared for 140 patient examinations (76 post‐ASiR implementation) to determine relative dose reduction and noise control.Results:CT numbers were constant to within 10% from the nondose reduced CTAC image for 90% dose reduction. No change in SUVbw, background percent uniformity, or spatial resolution for PET images reconstructed with CTAC protocols was found down to 90% dose reduction. Patient population effective dose analysis demonstrated relative CTAC dose reductions between 62% and 86% (3.2/8.3–0.9/6.2). Noise magnitude in dose‐reduced patient images increased but was not statistically different from predose‐reduced patient images.Conclusions:Using ASiR allowed for aggressive reduction in CT dose with no change in PET reconstructed images while maintaining sufficient image quality for colocalization of hybrid CT anatomy and PET radioisotope uptake.
Ionoacoustic characterization of the proton Bragg peak with submillimeter accuracy
Authors: Assmann W. , Kellnberger S. , Reinhardt S. , Lehrack S. , Edlich A. , Thirolf P. G. , Moser M. , Dollinger G. , Omar M. , Ntziachristos V. , Parodi K. 
Published: January 2015

Purpose:Range verification in ion beam therapy relies to date on nuclear imaging techniques which require complex and costly detector systems. A different approach is the detection of thermoacoustic signals that are generated due to localized energy loss of ion beams in tissue (ionoacoustics). Aim of this work was to study experimentally the achievable position resolution of ionoacoustics under idealized conditions using high frequency ultrasonic transducers and a specifically selected probing beam.Methods:A water phantom was irradiated by a pulsed 20 MeV proton beam with varying pulse intensity and length. The acoustic signal of single proton pulses was measured by different PZT‐based ultrasound detectors (3.5 and 10 MHz central frequencies). The proton dose distribution in water was calculated by Geant4 and used as input for simulation of the generated acoustic wave by the matlab toolbox k‐WAVE.Results:In measurements from this study, a clear signal of the Bragg peak was observed for an energy deposition as low as 1012 eV. The signal amplitude showed a linear increase with particle number per pulse and thus, dose. Bragg peak position measurements were reproducible within ±30 μm and agreed with Geant4 simulations to better than 100 μm. The ionoacoustic signal pattern allowed for a detailed analysis of the Bragg peak and could be well reproduced by k‐WAVE simulations.Conclusions:The authors have studied the ionoacoustic signal of the Bragg peak in experiments using a 20 MeV proton beam with its correspondingly localized energy deposition, demonstrating submillimeter position resolution and providing a deep insight in the correlation between the acoustic signal and Bragg peak shape. These results, together with earlier experiments and new simulations (including the results in this study) at higher energies, suggest ionoacoustics as a technique for range verification in particle therapy at locations, where the tumor can be localized by ultrasound imaging. This acoustic range verification approach could offer the possibility of combining anatomical ultrasound and Bragg peak imaging, but further studies are required for translation of these findings to clinical application.
Characterization of a double‐sided silicon strip detector autoradiography system
Authors: Örbom Anders , Ahlstedt Jonas , Serén Tom , Auterinen Iiro , Kotiluoto Petri , Hauge Håvard , Östlund Karl , Olafsen Tove , Wu Anna M. , Dahlbom Magnus , Strand Sven‐Erik 
Published: January 2015

Purpose:The most commonly used technology currently used for autoradiography is storage phosphor screens, which has many benefits such as a large field of view but lacks particle‐counting detection of the time and energy of each detected radionuclide decay. A number of alternative designs, using either solid state or scintillator detectors, have been developed to address these issues. The aim of this study is to characterize the imaging performance of one such instrument, a double‐sided silicon strip detector (DSSD) system for digital autoradiography. A novel aspect of this work is that the instrument, in contrast to previous prototype systems using the same detector type, provides the ability for user accessible imaging with higher throughput. Studies were performed to compare its spatial resolution to that of storage phosphor screens and test the implementation of multiradionuclide ex vivo imaging in a mouse preclinical animal study.Methods:Detector background counts were determined by measuring a nonradioactive sample slide for 52 h. Energy spectra and detection efficiency were measured for seven commonly used radionuclides under representative conditions for tissue imaging. System dead time was measured by imaging 18F samples of at least 5 kBq and studying the changes in count rate over time. A line source of 58Co was manufactured by irradiating a 10 μm nickel wire with fast neutrons in a research reactor. Samples of this wire were imaged in both the DSSD and storage phosphor screen systems and the full width at half maximum (FWHM) measured for the line profiles. Multiradionuclide imaging was employed in a two animal study to examine the intratumoral distribution of a 125I‐labeled monoclonal antibody and a 131I‐labeled engineered fragment (diabody) injected in the same mouse, both targeting carcinoembryonic antigen.Results:Detector background was 1.81 × 10−6 counts per second per 50 × 50 μm pixel. Energy spectra and detection efficiency were successfully measured for seven radionuclides. The system dead time was measured to be 59 μs, and FWHM for a 58Co line source was 154 ± 14 μm for the DSSD system and 343 ± 15 μm for the storage phosphor system. Separation of the contributions from 125I and 131I was performed on autoradiography images of tumor sections.Conclusions:This study has shown that a DSSD system can be beneficially applied for digital autoradiography with simultaneous multiradionuclide imaging capability. The system has a low background signal, ability to image both low and high activity samples, and a good energy resolution.
Arsenite Oxidase Also Functions as an Antimonite Oxidase
Authors: Wang Qian , Warelow Thomas P. , Kang Yoon-Suk , Romano Christine , Osborne Thomas H. , Lehr Corinne R. , Bothner Brian , McDermott Timothy R. , Santini Joanne M. , Wang Gejiao 
Published: January 2015

ABSTRACT

Arsenic and antimony are toxic metalloids and are considered priority environmental pollutants by the U.S. Environmental Protection Agency. Significant advances have been made in understanding microbe-arsenic interactions and how they influence arsenic redox speciation in the environment. However, even the most basic features of how and why a microorganism detects and reacts to antimony remain poorly understood. Previous work with
Agrobacterium tumefaciens
strain 5A concluded that oxidation of antimonite [Sb(III)] and arsenite [As(III)] required different biochemical pathways. Here, we show with
in vivo
experiments that a mutation in
aioA
[encoding the large subunit of As(III) oxidase] reduces the ability to oxidize Sb(III) by approximately one-third relative to the ability of the wild type. Further,
in vitro
studies with the purified As(III) oxidase from
Rhizobium
sp. strain NT-26 (AioA shares 94% amino acid sequence identity with AioA of
A. tumefaciens
) provide direct evidence of Sb(III) oxidation but also show a significantly decreased
V
max
compared to that of As(III) oxidation. The
aioBA
genes encoding As(III) oxidase are induced by As(III) but not by Sb(III), whereas
arsR
gene expression is induced by both As(III) and Sb(III), suggesting that detection and transcriptional responses for As(III) and Sb(III) differ. While Sb(III) and As(III) are similar with respect to cellular extrusion (ArsB or Acr3) and interaction with ArsR, they differ in the regulatory mechanisms that control the expression of genes encoding the different Ars or Aio activities. In summary, this study documents an enzymatic basis for microbial Sb(III) oxidation, although additional Sb(III) oxidation activity also is apparent in this bacterium.