bluuebunny/crossref_metadata_2025_split huggingface dataset:
WE‐B‐204C‐01: Postron Emission Mammography
Authors: MacDonald L 
Published: August 2010

Specialized positron emission tomography (PET) systems dedicated to imaging breast cancer have been proposed and developed since the mid‐1990s. The term positron emission mammography (PEM) has been applied to this specialized area of PET scanners and scanning.While progress has been made in reversing a long increasing trend of breast cancer deaths in the U.S. and elsewhere, there is still a relatively high incidence of breast cancer diagnosis and mortality: an estimated 192,000 cases, and 40,000 deaths in the U.S. in 2009. This is the second leading cause of cancer deaths in women in the U.S. Screening X‐ray mammography has played an important role in reversing the trend of increasing deaths, and is the primary imaging modality for breast cancer screening. A limitation of screening and diagnostic mammography is its lack of specificity to malignant disease, resulting in many false positives. A number of imaging methods are used to further investigate equivocal mammography findings, including ultrasound, magnetic resonance imaging (MRI), scintigraphy, and PEM.PET is a functional imaging modality used routinely in oncology to image hyper‐metabolic lesions, including breast cancers. However, the spatial resolution of whole‐body PET (WB‐PET) scanners limits their usefulness in early breast cancer because lesion sizes at diagnosis tend to be smaller than can be reliably imaged with WB‐PET. Dedicated PEM systems focus on improved spatial resolution for imaging early breast cancer, and its functional nature is seen to complement the morphological information provided by mammography. One proposed use of PEM is to improve specificity in diagnosing suspicious but equivocal findings in mammography. PEM has also been suggested for identifying multi‐focal, multi‐centric, or bilateral disease for purposes of planning surgical treatment, for guiding and monitoring therapies, and for better identification of ductal carcinoma in situ.This lecture will provide a brief history of PEM development, give the current status of PEM, compare PEM to WB‐PET and mammography, and discuss clinical applications and operations.Learning Objectives:1. At the end of this lecture, attendees should be able to2. Understand the differences between whole‐body PET and PEM3. Understand the differences between mammography and PEM4. List possible clinical applications/indications for PEM5. Describe clinical operation and requirements of PEM scanning
TH‐A‐204C‐01: Cone‐Beam CT: Principles Practicalities and Applications
Authors: Siewerdsen J 
Published: August 2010

The topic of C‐arm cone‐beam CT (CBCT) including principles of 3D reconstruction image quality radiation dose quality assurance and clinical applications. The availability of such systems has grown over the past several years particularly in light of performance enhancements gained through the incorporation of a flat‐panel detector (FPD) in the imaging chain in place of conventional x‐ray image intensifiers. Such FPD‐based systems demonstrate increased field of view higher 3D spatial resolution improved noise characteristics and the capability to visualize soft‐tissue structures. Applications include neurovascular and cardiovascular image‐guided interventions as well as a growing spectrum of nonvascular and tumor surgeries. The basic principles of cone‐beam CT image reconstruction are reviewed (focusing on prevalent implementations of the Feldkmp algorithm) in comparison to conventional fan‐beam filtered backprojection. The influence of image artifacts most relevant to C‐arm cone‐beam CT are reviewed — in particular x‐ray scatter object truncation and the “cone‐beam” artifact. The factors governing 3D image quality are explained with emphasis on the ability to image soft‐tissue structures and issues of radiation dose characterization and quality assurance are discussed. An ever‐increasing spectrum of C‐arm or C‐arm‐like cone‐beam CT systems is discussed in relation to various applications. Emphasis throughout is in regard to factors most relevant to the practicing medical physicists.Learning Objectives:1. Basic principles of 3D cone‐beam CT reconstruction2. Image quality and artifacts most relevant to cone‐beam CT3. Essential factors pertinent to C‐arm cone‐beam CT quality assurance4. Spectrum of systems and applications of C‐arm cone‐beam CT
TH‐C‐BRB‐09: Design and Initial Performance of a Large Cross‐Section Multi‐Element Ionization Chamber System for Water Equivalent Range Measurements of Pristine Proton Fields
Authors: Farr J , Mertens T , Bäumer C , Mukherjee B , Marchand B , Stuschke M 
Published: August 2010

Purpose: To describe the design and initial testing of a large diameter multilayer ionization chamber (MLIC) system for water equivalent range measurements of pristine proton fields. Method and Materials: The MLIC uses a large 120 mm physical diameter collecting cross‐section in a stacked vented parallel plate geometry of 180 layers spaced 0.8 mm apart. The plates are fabricated from printed circuit board material where copper traces have been etched to form the conductive elements for the ionization chambers. In addition a dedicated software package was developed to assist with device calibration data acquisition and analysis.Computer modeling of the MLIC was performed with the Monte Carlo (MC) code FLUKA. Radiological testing was performed in a dedicated proton pencil beam scanning (PBS) therapeutic delivery system. The energies tested varied from 100–230 MeV. A series of 10 pristine depth profiles were first acquired for reference within this energy range by longitudinally scanning a discrete parallel plate ionization chamber of 84 mm diameter in a water phantom. After a calibration routine was applied to the MLIC the same energies were tested with the MLIC and the results compared. Additional tests were performed at different fluence rates to evaluate changes in response to detector bias and charge quantum (QC) settings. Results: The analyzed data from the MC simulation and MLIC physical data compared within one mm to the water phantom reference data under the conditions tested. The MLIC results were not sensitive to bias setting but depended with fluence rate on the QC setting. Conclusion: The initial test of the new MLIC prototype provided satisfactory results with regard to water equivalent range accuracy in comparison to reference measurements from the PBS system. Some flexibility is provided with different fluence rates by adjusting the QC. The detailed results will be presented and discussed.
Simple Model for Testing Drugs against Nonreplicating
Mycobacterium tuberculosis
Authors: Sala Claudia , Dhar Neeraj , Hartkoorn Ruben C. , Zhang Ming , Ha Young Hwan , Schneider Patricia , Cole Stewart T. 
Published: August 2010

ABSTRACT

Nonreplicating or dormant cells of
Mycobacterium tuberculosis
constitute a challenge to tuberculosis (TB) therapy because of their tolerance or phenotypic resistance to most drugs. Here, we propose a simple model for testing drugs against nongrowing cells that exploits the 18b strain of
M. tuberculosis
, a streptomycin (STR)-dependent mutant. Optimal conditions were established that allowed 18b cells to replicate in the presence of STR and to survive, but not multiply, following withdrawal of STR. In the presence of the antibiotic,
M. tuberculosis
18b was susceptible to the currently approved TB drugs, isoniazid (INH) and rifampin (RIF), and to the experimental drugs TMC207, PA-824, meropenem (MER), benzothiazinone (BTZ), and moxifloxacin (MOXI). After STR depletion, the strain displayed greatly reduced susceptibility to the cell wall inhibitors INH and BTZ but showed increased susceptibility to RIF and PA-824, while MOXI and MER appeared equipotent under both conditions. The same potency ranking was found against nonreplicating
M. tuberculosis
18b after
in vivo
treatment of chronically infected mice with five of these drugs. Despite the growth arrest, strain 18b retains significant metabolic activity
in vitro
, remaining positive in the resazurin reduction assay. Upon adaption to a 96-well format, this assay was shown to be suitable for high-throughput screening with strain 18b to find new inhibitors of dormant
M. tuberculosis
.
Three
Yersinia pestis
Adhesins Facilitate Yop Delivery to Eukaryotic Cells and Contribute to Plague Virulence
Authors: Felek Suleyman , Tsang Tiffany M. , Krukonis Eric S. 
Published: August 2010

ABSTRACT

To establish a successful infection,
Yersinia pestis
requires the delivery of cytotoxic Yops to host cells. Yops inhibit phagocytosis, block cytokine responses, and induce apoptosis of macrophages. The
Y. pestis
adhesin Ail facilitates Yop translocation and is required for full virulence in mice. To determine the contributions of other adhesins to Yop delivery, we deleted five known adhesins of
Y. pestis
. In addition to Ail, plasminogen activator (Pla) and pH 6 antigen (Psa) could mediate Yop translocation to host cells. The contribution of each adhesin to binding and Yop delivery was dependent upon the growth conditions. When cells were pregrown at 28°C and pH 7, the order of importance for adhesins in cell binding and cytotoxicity was Ail > Pla > Psa.
Y. pestis
grown at 37°C and pH 7 had equal contributions from Ail and Pla but an undetectable role for Psa. At 37°C and pH 6, both Ail and Psa contributed to binding and Yop delivery, while Pla contributed minimally. Pla-mediated Yop translocation was independent of protease activity. Of the three single mutants, the Δ
ail
mutant was the most defective in mouse virulence. The expression level of
ail
was also the highest of the three adhesins in infected mouse tissues. Compared to an
ail
mutant, additional deletion of
psaA
(encoding Psa) led to a 130,000-fold increase in the 50% lethal dose for mice relative to that of the KIM5 parental strain. Our results indicate that in addition to Ail, Pla and Psa can serve as environmentally specific adhesins to facilitate Yop secretion, a critical virulence function of
Y. pestis
.
Mucosal Immunization withVibrio choleraeOuter Membrane Vesicles Provides Maternal Protection Mediated by Antilipopolysaccharide Antibodies That Inhibit Bacterial Motility
Authors: Bishop Anne L. , Schild Stefan , Patimalla Bharathi , Klein Brian , Camilli Andrew 
Published: August 2010

ABSTRACTVibrio choleraeis the causative agent of cholera, a severe diarrheal disease that remains endemic in many parts of the world and can cause outbreaks wherever sanitation and clean water systems break down. Prevention of disease could be achieved through improved sanitation and clean water provision supported by vaccination.V. choleraeserogroup O1 is the major cause of cholera; O1 serotypes Inaba and Ogawa have similar disease burdens, while O139 is the only non-O1 serogroup to cause epidemics. We showed previously that immunization of adult female mice with purifiedV. choleraeouter membrane vesicles (OMVs) elicits an antibody response that protect neonates from oralV. choleraechallenge and that suckling from an immunized dam accounts for the majority of protection fromV. choleraecolonization. Here we report that lipopolysaccharide (LPS) is the major OMV protective antigen. Mucosal immunization with OMVs from Inaba or Ogawa provides significant cross-serotype protection fromV. choleraecolonization, although serotype-specific antigens are dominant. OMVs from O1 or O139 do not provide cross-serogroup protection, but by immunization with a mixture of O1 and O139 OMVs, cross-serogroup protection was achieved. Neonatal protection is not associated with significant bacterial death but may involve inhibition of motility, as antibodies from OMV-immunized mice inhibitV. choleraemotilityin vitro, with trends that parallelin vivoprotection. Motility assays also reveal that a higher antibody titer is required to immobilize O139 compared to O1, a phenotype that is O139 capsule dependent.
Impaired Immune Tolerance toPorphyromonas gingivalisLipopolysaccharide Promotes Neutrophil Migration and Decreased Apoptosis
Authors: Zaric Svetislav , Shelburne Charles , Darveau Richard , Quinn Derek J. , Weldon Sinéad , Taggart Clifford C. , Coulter Wilson A. 
Published: August 2010

ABSTRACTPeriodontitis, a chronic inflammatory disease of the tissues supporting the teeth, is characterized by an exaggerated host immune and inflammatory response to periopathogenic bacteria. Toll-like receptor activation, cytokine network induction, and accumulation of neutrophils at the site of inflammation are important in the host defense against infection. At the same time, induction of immune tolerance and the clearance of neutrophils from the site of infection are essential in the control of the immune response, resolution of inflammation, and prevention of tissue destruction. Using a human monocytic cell line, we demonstrate thatPorphyromonas gingivalislipopolysaccharide (LPS), which is a major etiological factor in periodontal disease, induces only partial immune tolerance, with continued high production of interleukin-8 (IL-8) but diminished secretion of tumor necrosis factor alpha (TNF-α) after repeated challenge. This cytokine response has functional consequences for other immune cells involved in the response to infection. Primary human neutrophils incubated withP. gingivalisLPS-treated naïve monocyte supernatant displayed a high migration index and increased apoptosis. In contrast, neutrophils treated withP. gingivalisLPS-tolerized monocyte supernatant showed a high migration index but significantly decreased apoptosis. Overall, these findings suggest that induction of an imbalanced immune tolerance in monocytes byP. gingivalisLPS, which favors continued secretion of IL-8 but decreased TNF-α production, may be associated with enhanced migration of neutrophils to the site of infection but also with decreased apoptosis and may play a role in the chronic inflammatory state seen in periodontal disease.
Pathogenic Role of Macrophages in Intradermal Infection of Methicillin-Resistant
Staphylococcus aureus
in Thermally Injured Mice
Authors: Asai Akira , Tsuda Yasuhiro , Kobayashi Makiko , Hanafusa Toshiaki , Herndon David N. , Suzuki Fujio 
Published: August 2010

ABSTRACT

Intradermal infection of methicillin-resistant
Staphylococcus aureus
(MRSA) in burned mice was pathogenically analyzed. An abscess was formed in normal mice intradermally infected with 10
8
CFU/mouse of MRSA, and all of these mice survived after the infection; however, abscess formation was not demonstrated to occur in burned mice similarly exposed to the pathogen, and all of these mice died within 5 days of infection. In burned mice, MRSA infected at the burn site intradermal tissues spread quickly throughout the whole body, while in normal mice, the pathogen remained localized at the infection site. Macrophages (Mφ) isolated from the infection site tissues of normal mice produced interleukin-12 (IL-12) but not IL-10 and were characterized as M1Mφ. These M1Mφ were not isolated from the infection site tissues of burned mice. When normal-mouse infection site tissue Mφ were adoptively transferred to burned mice at the MRSA infection site, an abscess formed, and the infection did not develop into sepsis. In contrast, an abscess did not form and sepsis developed in normal mice that were inoculated with burned-mouse infection site tissue Mφ. These Mφ produced IL-10 but not IL-12 and were characterized as M2Mφ. These results indicate that abscess formation is a major mechanism of host resistance against intradermal MRSA infection. M1Mφ in the tissues surrounding the infection site play a pivotal role in abscess formation; however, the abscess is not formed in burned mice where M2Mφ predominate. M2Mφ have been described as inhibitor cells for Mφ conversion from resident Mφ to M1Mφ.
Strong Convergence Theorems for a Generalized Equilibrium Problem with a Relaxed Monotone Mapping and a Countable Family of Nonexpansive Mappings in a Hilbert Space
Authors: Wang Shenghua , Marino Giuseppe , Wang Fuhai 
Published: August 2010

AbstractWe introduce a new iterative method for finding a common element of the set of solutions of a generalized equilibrium problem with a relaxed monotone mapping and the set of common fixed points of a countable family of nonexpansive mappings in a Hilbert space and then prove that the sequence converges strongly to a common element of the two sets. Using this result, we prove several new strong convergence theorems in fixed point problems, variational inequalities, and equilibrium problems.
Distance measurements via the morphogen gradient of Bicoid in Drosophila embryos
Authors: He Feng , Wen Ying , Cheung David , Deng Jingyuan , Lu Long J , Jiao Renjie , Ma Jun 
Published: August 2010

AbstractBackgroundPatterning along the anterior-posterior (A-P) axis inDrosophilaembryos is instructed by the morphogen gradient of Bicoid (Bcd). Despite extensive studies of this morphogen, how embryo geometry may affect gradient formation and target responses has not been investigated experimentally.ResultsIn this report, we systematically compare the Bcd gradient profiles and its target expression patterns on the dorsal and ventral sides of the embryo. Our results support a hypothesis that proper distance measurement and the encoded positional information of the Bcd gradient are along the perimeter of the embryo. Our results also reveal that the dorsal and ventral sides of the embryo have a fundamentally similar relationship between Bcd and its target Hunchback (Hb), suggesting that Hb expression properties on the two sides of the embryo can be directly traced to Bcd gradient properties. Our 3-D simulation studies show that a curvature difference between the two sides of an embryo is sufficient to generate Bcd gradient properties that are consistent with experimental observations.ConclusionsThe findings described in this report provide a first quantitative, experimental evaluation of embryo geometry on Bcd gradient formation and target responses. They demonstrate that the physical features of an embryo, such as its shape, are integral to how pattern is formed.
Growth-related quantitative trait loci in domestic and wild rainbow trout (Oncorhynchus mykiss)
Authors: Wringe Brendan F , Devlin Robert H , Ferguson Moira M , Moghadam Hooman K , Sakhrani Dionne , Danzmann Roy G 
Published: August 2010

AbstractBackgroundSomatic growth is a complex process that involves the action and interaction of genes and environment. A number of quantitative trait loci (QTL) previously identified for body weight and condition factor in rainbow trout (Oncorhynchus mykiss), and two other salmonid species, were used to further investigate the genetic architecture of growth-influencing genes in this species. Relationships among previously mapped candidate genes for growth and their co-localization to identified QTL regions are reported. Furthermore, using a comparative genomic analysis of syntenic rainbow trout linkage group clusters to their homologous regions within model teleost species such as zebrafish, stickleback and medaka, inferences were made regarding additional possible candidate genes underlying identified QTL regions.ResultsBody weight (BW) QTL were detected on the majority of rainbow trout linkage groups across 10 parents from 3 strains. However, only 10 linkage groups (i.e., RT-3, -6, -8, -9, -10, -12, -13, -22, -24, -27) possessed QTL regions with chromosome-wide or genome-wide effects across multiple parents. Fewer QTL for condition factor (K) were identified and only six instances of co-localization across families were detected (i.e. RT-9, -15, -16, -23, -27, -31 and RT-2/9 homeologs). Of note, both BW and K QTL co-localize on RT-9 and RT-27. The incidence of epistatic interaction across genomic regions within different female backgrounds was also examined, and although evidence for interaction effects within certain QTL regions were evident, these interactions were few in number and statistically weak. Of interest, however, was the fact that these predominantly occurred within K QTL regions. Currently mapped growth candidate genes are largely congruent with the identified QTL regions. More QTL were detected in male, compared to female parents, with the greatest number evident in an F1male parent derived from an intercross between domesticated and wild strain of rainbow trout which differed strongly in growth rate.ConclusionsStrain background influences the degree to which QTL effects are evident for growth-related genes. The process of domestication (which primarily selects faster growing fish) may largely reduce the genetic influences on growth-specific phenotypic variation. Although heritabilities have been reported to be relatively high for both BW and K growth traits, the genetic architecture of K phenotypic variation appears less defined (i.e., fewer major contributing QTL regions were identified compared with BW QTL regions).
The common rs9939609 variant of the fat mass and obesity-associated gene is associated with obesity risk in children and adolescents of Beijing, China
Authors: Xi Bo , Shen Yue , Zhang Meixian , Liu Xin , Zhao Xiaoyuan , Wu Lijun , Cheng Hong , Hou Dongqing , Lindpaintner Klaus , Liu Lisheng , Mi Jie , Wang Xingyu 
Published: August 2010

AbstractBackgroundPrevious genome-wide association studies for type 2 diabetes susceptibility genes have confirmed that a common variant, rs9939609, in the fat mass and obesity associated (FTO) gene region is associated with body mass index (BMI) in European children and adults. A significant association of the same risk allele has been described in Asian adult populations, but the results are conflicting. In addition, no replication studies have been conducted in children and adolescents of Asian ancestry.MethodsA population-based survey was carried out among 3503 children and adolescents (6-18 years of age) in Beijing, China, including 1229 obese and 2274 non-obese subjects. We investigated the association of rs9939609 with BMI and the risk of obesity. In addition, we tested the association of rs9939609 with weight, height, waist circumference, waist-to-height ratio, fat mass percentage, birth weight, blood pressure and related metabolic traits.ResultsWe found significant associations of rs9939609 variant with weight, BMI, BMI standard deviation score (BMI-SDS), waist circumference, waist-to-height ratio, and fat mass percentage in children and adolescents (pfor trend = 3.29 × 10-5, 1.39 × 10-6, 3.76 × 10-6, 2.26 × 10-5, 1.94 × 10-5, and 9.75 × 10-5, respectively). No significant associations were detected with height, birth weight, systolic and diastolic blood pressure and related metabolic traits such as total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol and fasting plasma glucose (allp> 0.05). Each additional copy of the rs9939609 A allele was associated with a BMI increase of 0.79 [95% Confidence interval (CI) 0.47 to 1.10] kg/m2, equivalent to 0.25 (95%CI 0.14 to 0.35) BMI-SDS units. This rs9939609 variant is significantly associated with the risk of obesity under an additive model [Odds ratio (OR) = 1.29, 95% CI 1.11 to 1.50] after adjusting for age and gender. Moreover, an interaction between theFTOrs9939609 genotype and physical activity (p< 0.001) was detected on BMI levels, the effect of rs9939609-A allele on BMI being (0.95 ± 0.10), (0.77 ± 0.08) and (0.67 ± 0.05) kg/m2, for subjects who performed low, moderate and severe intensity physical activity.ConclusionTheFTOrs9939609 variant is strongly associated with BMI and the risk of obesity in a population of children and adolescents in Beijing, China.