bluuebunny/crossref_metadata_2025 huggingface dataset:
Physical models, cross sections, and numerical approximations used inMCNPandGEANT4Monte Carlo codes for photon and electron absorbed fraction calculation
Authors: Yoriyaz Hélio , Moralles Maurício , de Tarso Dalledone Siqueira Paulo , da Costa Guimarães Carla , Belonsi Cintra Felipe , dos Santos Adimir
Published: October 2009

Purpose:

Radiopharmaceutical applications in nuclear medicine require a detailed dosimetry estimate of the radiation energy delivered to the human tissues. Over the past years, several publications addressed the problem of internal dose estimate in volumes of several sizes considering photon and electron sources. Most of them used Monte Carlo radiation transport codes. Despite the widespread use of these codes due to the variety of resources and potentials they offered to carry out dose calculations, several aspects like physical models, cross sections, and numerical approximations used in the simulations still remain an object of study. Accurate dose estimate depends on the correct selection of a set of simulation options that should be carefully chosen. This article presents an analysis of several simulation options provided by two of the most used codes worldwide:MCNPandGEANT4.

Methods:

For this purpose, comparisons of absorbed fraction estimates obtained with different physical models, cross sections, and numerical approximations are presented for spheres of several sizes and composed as five different biological tissues.

Results:

Considerable discrepancies have been found in some cases not only between the different codes but also between different cross sections and algorithms in the same code. Maximum differences found between the two codes are 5.0% and 10%, respectively, for photons and electrons.

Conclusion:

Even for simple problems as spheres and uniform radiation sources, the set of parameters chosen by any Monte Carlo code significantly affects the final results of a simulation, demonstrating the importance of the correct choice of parameters in the simulation.
Three‐dimensional ultrasound system for guided breast brachytherapy
Authors: De Jean Paul , Beaulieu Luc , Fenster Aaron
Published: October 2009

Breast‐conserving surgery combined with subsequent radiation therapy is a standard procedure in breast cancer treatment. The disadvantage of whole‐breast beam irradiation is that it requires 20–25 treatment days, which is inconvenient for patients with limited mobility or who reside far from the treatment center. However, interstitial high‐dose‐rate (HDR) brachytherapy is an irradiation method requiring only 5 treatment days and that delivers a lower radiation dose to the surrounding healthy tissue. It involves delivering radiation through seeds placed inside the catheters, which are inserted into the breast. The catheters are attached to a HDR afterloader, which controls the seed placement within the catheters and irradiation times to deliver the proper radiation dose. One disadvantage of using HDR brachytherapy is that it requires performing at least one CT scan during treatment planning. The procedure at our institution involves the use of two CT scans. Performing CT scans requires moving the patient from the brachytherapy suite with catheters inserted in their breasts. One alternative is using three‐dimensional ultrasound (3DUS) to image the patient. In this study, the authors developed a 3DUS translation scanning system for use in breast brachytherapy. The new system was validated using CT, the current clinical standard, to image catheters in a breast phantom. Once the CT and 3DUS images were registered, the catheter trajectories were then compared. The results showed that the average angular separation between catheter trajectories was 2.4°, the average maximum trajectory separation was , and the average mean trajectory separation was found to be . In this article, the authors present the 3DUS translation scanning system's capabilities as well as its potential to be used as the primary treatment planning imaging modality in breast brachytherapy.
More than 10 years experience of beam monitoring with the Gantry 1 spot scanning proton therapy facility at PSI
Authors: Lin Shixiong , Boehringer Terence , Coray Adolf , Grossmann Martin , Pedroni Eros
Published: October 2009

Purpose:

The beam monitoring equipments developed for the first PSI spot scanning proton therapy facility, Gantry 1, have been successfully used for more than 10 years. The purpose of this article is to summarize the author's experience in the beam monitoring technique for dynamic proton scanning.

Methods:

The spot dose delivery and verification use two independent beam monitoring and computer systems. In this article, the detector construction, electronic system, dosimetry, and quality assurance results are described in detail. The beam flux monitor is calibrated with a Faraday cup. The beam position monitoring is realized by measuring the magnetic fields of deflection magnets with Hall probes before applying the spot and by checking the beam position and width with an ionization strip chamber after the spot delivery.

Results:

The results of thimble ionization chamber dosimetry measurements are reproducible (with a mean deviation of less than 1% and a standard deviation of 1%). The resolution in the beam position measurement is of the order of a tenth of a millimeter. The tolerance of the beam position delivery and monitoring during scanning is less than 1.5 mm.

Conclusions:

The experiences gained with the successful operation of Gantry 1 represent a unique and solid background for the development of a new system, Gantry 2, in order to perform new advanced scanning techniques.
Photon counting multienergy x‐ray imaging: Effect of the characteristic x rays on detector performance
Authors: Shikhaliev Polad M. , Fritz Shannon G. , Chapman John W.
Published: October 2009

Purpose:

The purpose of this work was to investigate the effect of characteristic x rays on the performance of photon counting detectors for multienergy x‐ray imaging. X‐ray and CT systems with photon counting detectors have compelling advantages compared to energy integrating detectors, and cadmium zinc telluride (CZT) detector is the detector of choice. However, current CZT detectors exhibit several limitations that hamper their practical applications. These limitations include hole trapping, high leakage current, and charge sharing between detector pixels. Charge sharing occurs due to the diffusion of charge when it drifts toward the pixel electrodes. It also occurs due to nonlocal reabsorption of characteristic and scattered x rays created in the detector volume. Hole trapping, leakage current, and charge diffusion may potentially have technical solutions. Characteristic x‐ray escape and scatter, however, are fundamental in nature and cannot be easily addressed. The x‐ray scatter in the CZT material is small at photon energies used in x‐ray imaging. Therefore, the remaining major factor is characteristic x ray.

Methods:

Monte Carlo simulations were used for this study. An experimental photon counting multienergy x‐ray imaging system was used to compare simulations to experimental results. An x‐ray spectrum at 120 kVp tube voltage was used. The x‐ray energy range was split into five subregions (energy bins) and Monte Carlo simulations were performed at average x‐ray energies corresponding to these energy bins. The detector pixel size was changed within the 0.1–1 mm range, which covered all possible applications including radiography and CT imaging. The pixel shapes included square and strip pixels. For strip pixels, tilted angle irradiation of the CZT detector was also investigated.

Results:

The characteristic x rays escaped the pixels in approximately 70% of all x‐ray interactions for the smallest pixel size of 0.1 mm. The escape fraction decreased to 20% for the largest pixel size of 1 mm. All escape fractions, for all pixel sizes, at five energies, for square and strip pixels, and at three tilt angles were calculated and presented in tables. Simulated and measured spectra at 120 kVp were compared.

Conclusions:

Characteristic x‐ray escape deteriorates energy and spatial resolution, particularly for small pixel sizes. Correction methods should be developed based on the results of the simulations and experimental study.
Compact x‐ray sources for mammographic applications: Monte Carlo simulations of image quality
Authors: Oliva P. , Golosio B. , Stumbo S. , Bravin A. , Tomassini P.
Published: October 2009

Thomson scattering x‐ray sources can provide spectral distributions that are ideally suited for mammography with sufficient fluence rates. In this article, the authors investigate the effects of different spectral distributions on the image quality in simulated images of a breast mammographic phantom containing details of different compositions and thicknesses. They simulated monochromatic, quasimonochromatic, and polychromatic x‐ray sources in order to define the energy for maximum figure of merit (signal‐difference‐to‐noise ratio squared/mean glandular dose), the effect of an energy spread, and the effect of the presence of higher‐order harmonics. The advantages of these sources with respect to conventional polychromatic sources as a function of phantom and detail thickness were also investigated. The results show that the energy for the figure of merit peak is between 16 and 27.4 keV, depending on the phantom thickness and detail composition and thickness. An energy spread of about 1 keV standard deviation, easily achievable with compact x‐ray sources, does not appreciably affect the image quality.
Investigation of the dosimetric accuracy of the isocenter shifting method in prostate cancer patients with and without hip prostheses
Authors: Hwang Andrew B. , Kinsey Erica , Xia Ping
Published: October 2009

Purpose:

The use of image guided radiation therapy (IGRT) enables compensation for prostate movement by shifting the treatment isocenter to track the prostate on a daily basis. Although shifting the isocenter can alter the source to skin distances (SSDs) and the effective depth of the target volume, it is commonly assumed that these changes have a negligible dosimetric effect, and therefore, the number of monitor units delivered is usually not adjusted. However, it is unknown whether or not this assumption is valid for patient with hip prostheses, which frequently contain high density materials.

Methods:

The authors conducted a retrospective study to investigate dosimetric effect of the isocenter shifting method for prostate patients with and without hip prostheses. For each patient, copies of the prostate volume were shifted by up to 1.5 cm from the original position to simulate prostate movement in 0.5 cm increments. Subsequently, 12 plans were created for each patient by creating a copy of the original plan for each prostate position with the isocenter shifted to track the position of the shifted prostate. The dose to the prostate was then recalculated for each plan. For patients with hip prostheses, plans were created both with and without lateral beam angles entering through the prostheses.

Results:

Without isocenter shifting to compensate for prostate motion of 1.5 cm, the dose to the 95% of the prostate changed by an average of 30% and by up to 64%. This was reduced to less than 3% with the isocenter shifting method. It was found that for patients with hip prostheses, this technique worked best for treatment plans that avoided beam angles passing through the prostheses.

Conclusions:

The results demonstrated that the isocenter shifting method can accurately deliver dose to the prostate even in patients with hip prostheses.
Quorum Sensing Negatively Regulates Hemolysin Transcriptionally and Posttranslationally in
Vibrio cholerae
Authors: Tsou Amy M. , Zhu Jun
Published: October 2009

Recent work has shown that in addition to cholera toxin (CT) and the toxin-coregulated pilus (TCP), other cytotoxic proteins in
Vibrio cholerae
also cause disease symptoms, and this is particularly evident in strains lacking CT. One such protein is the hemolysin encoded by
hlyA
. Here we show that, like CT and TCP, HlyA is repressed by the quorum-sensing-regulated transcription factor HapR. This repression occurs on two levels: one at the transcriptional level that is independent of the metalloprotease HapA and one at the posttranslational level that is mediated by HapA. The transcriptional regulation is significantly more apparent on solid media than in liquid cultures. This is the first time that hemolysis has been shown to be directly regulated by quorum sensing in
V. cholerae
, and it is interesting that, like other virulence factors, HlyA is also repressed by HapR, which is expressed late in infection.
Functional Characterization ofBorrelia spielmaniiOuter Surface Proteins That Interact with Distinct Members of the Human Factor H Protein Family and with Plasminogen
Authors: Seling Annekatrin , Siegel Corinna , Fingerle Volker , Jutras Brandon L. , Brissette Catherine A. , Skerka Christine , Wallich Reinhard , Zipfel Peter F. , Stevenson Brian , Kraiczy Peter
Published: October 2009

Acquisition of complement regulator factor H (CFH) and factor H-like protein 1 (CFHL1) from human serum enablesBorrelia spielmanii, one of the etiological agents of Lyme disease, to evade complement-mediated killing by the human host. Up to three distinct complement regulator-acquiring surface proteins (CRASPs) may be expressed by serum-resistantB. spielmanii, each exhibiting an affinity for CFH and/or CFHL1. Here, we describe the functional characterization of the 15-kDa CRASPs ofB. spielmanii, members of the polymorphic Erp (OspE/F-related) protein family, that bind two distinct host complement regulators, CFH and factor H-related protein 1 (CFHR1), but not CFHL1. CFH bound to theB. spielmaniiCRASPs maintained cofactor activity for factor I-mediated C3b inactivation. Three naturally occurring alleles of this protein bound CFH and CFHR1 while a fourth natural allele could not. Comparative sequence analysis of these protein alleles identified a single amino acid, histidine-79, as playing a significant role in CFH/CFHR1 binding, with substitution by an arginine completely abrogating ligand binding. The mutation of His-79 to Arg did not inhibit binding of plasminogen, another known ligand of this group of borrelial outer-surface proteins.
Production of Reactive Oxygen Species Is Turned On and Rapidly Shut Down in Epithelial Cells Infected with
Chlamydia trachomatis
Authors: Boncompain Gaëlle , Schneider Benoît , Delevoye Cédric , Kellermann Odile , Dautry-Varsat Alice , Subtil Agathe
Published: October 2009

Reactive oxygen species (ROS) are many-faceted compounds involved in cell defense against pathogens, as well as in cell signaling. Their involvement in the response to infection in epithelial cells remains poorly documented. Here, we investigated the production of ROS during infection with
Chlamydia trachomatis
, a strict intracellular pathogen, in HeLa cells.
C. trachomatis
induced a transient increase in the ROS level within a few hours, followed by a return to basal level 9 hours after infection. At this time point, the host enzyme dedicated to ROS production, NADPH oxidase, could no longer be activated by external stimuli, such as interleukin-1β. In addition, Rac, a regulatory subunit of the NADPH oxidase complex, was relocated to the membrane of the compartment in which the bacteria develop, the inclusion, while other subunits were not. Altogether, these results indicate that
C. trachomatis
infection elicits the production of ROS and that the bacteria rapidly target the activity of NADPH oxidase to shut it down. Prevention of ROS production at the onset of the bacterial developmental cycle might delay the host response to infection.
Prime-Boost Immunization with Adenoviral and Modified Vaccinia Virus Ankara Vectors Enhances the Durability and Polyfunctionality of Protective Malaria CD8
+
T-Cell Responses
Authors: Reyes-Sandoval Arturo , Berthoud Tamara , Alder Nicola , Siani Loredana , Gilbert Sarah C. , Nicosia Alfredo , Colloca Stefano , Cortese Riccardo , Hill Adrian V. S.
Published: October 2009

Protection against liver-stage malaria relies on the induction of high frequencies of antigen-specific CD8
+
T cells. We have previously reported high protective levels against mouse malaria, albeit short-lived, by a single vaccination with adenoviral vectors coding for a liver-stage antigen (ME.TRAP). Here, we report that prime-boost regimens using modified vaccinia virus Ankara (MVA) and adenoviral vectors encoding ME.TRAP can enhance both short- and long-term sterile protection against malaria. Protection persisted for at least 6 months when simian adenoviruses AdCh63 and AdC9 were used as priming vectors. Kinetic analysis showed that the MVA boost made the adenoviral-primed T cells markedly more polyfunctional, with the number of gamma interferon (INF-γ), tumor necrosis factor alpha (TNF-α), and interleukin-2 (IL-2) triple-positive and INF-γ and TNF-α double-positive cells increasing over time, while INF-γ single-positive cells declined with time. However, IFN-γ production prevailed as the main immune correlate of protection, while neither an increase of polyfunctionality nor a high integrated mean fluorescence intensity (iMFI) correlated with protection. These data highlight the ability of optimized viral vector prime-boost regimens to generate more protective and sustained CD8
+
T-cell responses, and our results encourage a more nuanced assessment of the importance of inducing polyfunctional CD8
+
T cells by vaccination.
Characterization of Virulence Plasmid Diversity among
Clostridium perfringens
Type B Isolates
Authors: Sayeed Sameera , Li Jihong , McClane Bruce A.
Published: October 2009

The important veterinary pathogen
Clostridium perfringens
type B is unique for producing the two most lethal
C
.
perfringens
toxins, i.e., epsilon-toxin and beta-toxin. Our recent study (K. Miyamoto, J. Li, S. Sayeed, S. Akimoto, and B. A. McClane, J. Bacteriol. 190:7178-7188, 2008) showed that most, if not all, type B isolates carry a 65-kb epsilon-toxin-encoding plasmid. However, this epsilon-toxin plasmid did not possess the
cpb
gene encoding beta-toxin, suggesting that type B isolates carry at least one additional virulence plasmid. Therefore, the current study used Southern blotting of pulsed-field gels to localize the
cpb
gene to ∼90-kb plasmids in most type B isolates, although a few isolates carried a ∼65-kb
cpb
plasmid distinct from their
etx
plasmid. Overlapping PCR analysis then showed that the gene encoding the recently discovered TpeL toxin is located ∼3 kb downstream of the plasmid-borne
cpb
gene. As shown earlier for their epsilon-toxin-encoding plasmids, the beta-toxin-encoding plasmids of type B isolates were found to carry a
tcp
locus, suggesting that they are conjugative. Additionally, IS
1151
-like sequences were identified upstream of the
cpb
gene in type B isolates. These IS
1151
-like sequences may mobilize the
cpb
gene based upon detection of possible
cpb-
containing circular transposition intermediates. Most type B isolates also possessed a third virulence plasmid that carries genes encoding urease and lambda-toxin. Collectively, these findings suggest that type B isolates are among the most plasmid dependent of all
C. perfringens
isolates for virulence, as they usually carry three potential virulence plasmids.
Systematic Analysis of the SsrAB Virulon of
Salmonella enterica
Authors: Xu Xin , Hensel Michael
Published: October 2009

Intracellular
Salmonella enterica
serovar Typhimurium deploys the
Salmonella
pathogenicity island 2 (SPI2)-encoded type III secretion system (T3SS) to modify host cell functions and accomplish intracellular replication. This virulence function is controlled by the two-component system SsrAB that regulates the expression of several operons in SPI2 and, in addition, a large number of genes for non-SPI2-encoded effector proteins. Here, we analyzed the relative expression levels of members of the SsrAB virulon. We used a novel reporter fusion strategy for single-copy chromosomal fusions, all done in an identical manner in order to enable direct quantitative comparison. We observed very high expression levels for
sseJ
and
sifA
; high expression levels for
ssaG
,
steC
,
sseL
, and
sopD2
; moderate expression levels for
ssaB
,
sseA
,
sseG
,
sifB
,
pipB2
, and
sspH1
; and low expression levels for
sspH2
,
sseI
,
slrP
,
sseK1
,
sseK2
,
pipB
, and
gogB
. The expression of the SsrAB virulon was highly dependent on the function of SsrB but also required EnvR/OmpZ. Deletion of PhoP, part of the global regulatory system PhoPQ, resulted in highly delayed expression of the SsrAB virulon under in vitro conditions; however, maximal expression was similar to that in a wild-type background. The expression levels of SsrAB-dependent genes in intracellular bacteria were in good agreement with in vitro analyses. We provide here a comprehensive and fully comparable analysis of the expression of genes in the SsrAB virulon. This information will be of interest for the selection of in vivo-activated promoters, for example, for rational design of recombinant vaccines.
Acid Phosphatases Do Not Contribute to the Pathogenesis of Type A
Francisella tularensis
Authors: Child Robert , Wehrly Tara D. , Rockx-Brouwer Dedeke , Dorward David W. , Celli Jean
Published: October 2009

The intracellular pathogen
Francisella tularensis
is the causative agent of tularemia, a zoonosis that can affect humans with potentially lethal consequences. Essential to
Francisella
virulence is its ability to survive and proliferate within phagocytes through phagosomal escape and cytosolic replication.
Francisella
spp. encode a variety of acid phosphatases, whose roles in phagosomal escape and virulence have been documented yet remain controversial. Here we have examined in the highly virulent (type A)
F
.
tularensis
strain Schu S4 the pathogenic roles of three distinct acid phosphatases, AcpA, AcpB, and AcpC, that are most conserved between
Francisella
subspecies. Neither the deletion of
acpA
nor the combination of
acpA
,
acpB
, and
acpC
deletions affected the phagosomal escape or cytosolic growth of Schu S4 in murine and human macrophages, despite decreases in acid phosphatase activities by as much as 95%. Furthermore, none of these mutants were affected in their ability to cause lethality in mice upon intranasal inoculation. Hence, the acid phosphatases AcpA, AcpB, and AcpC do not contribute to intracellular pathogenesis and do not play a major role in the virulence of type A
Francisella
strains.
Impairment of Gamma Interferon Signaling in Human Neutrophils Infected withAnaplasma phagocytophilum
Authors: Bussmeyer Uta , Sarkar Arup , Broszat Kirsten , Lüdemann Tanja , Möller Sonja , van Zandbergen Ger , Bogdan Christian , Behnen Martina , Dumler J. Stephen , von Loewenich Friederike D. , Solbach Werner , Laskay Tamás
Published: October 2009

Anaplasma phagocytophilum, the causative agent of tick-borne human granulocytic anaplasmosis (HGA), is an intracellular bacterium which survives and multiplies inside polymorphonuclear neutrophil granulocytes (PMN). Increased bacterial burden in gamma interferon (IFN-γ)-deficient mice suggested a major role of IFN-γ in the control ofA. phagocytophilum. Here we investigated whether infection of human PMN withA. phagocytophilumimpairs IFN-γ signaling thus facilitating intracellular survival of the bacterium. The secretion of the IFN-γ-inducible chemokines IP-10/CXCL10 and MIG/CXCL9 was markedly inhibited in infected neutrophils. Molecular analyses revealed that, compared to uninfected PMN,A. phagocytophilumdecreased the expression of the IFN-γ receptor α-chain CD119, diminished the IFN-γ-induced phosphorylation of STAT1, and enhanced the expression of SOCS1 and SOCS3 in PMN. Since IFN-γ activates various antibacterial effector mechanisms of PMN, the impaired IFN-γ signaling in infected cells likely contributes to the survival ofA. phagocytophiluminside PMN and to HGA disease development.
Characterization of a ConditionalbosRMutant inBorrelia burgdorferi
Authors: Hyde Jenny A. , Shaw Dana K. , Smith Roger , Trzeciakowski Jerome P. , Skare Jon T.
Published: October 2009

Borrelia burgdorferi, the etiological agent of Lyme disease, adapts to unique host environments as a consequence of its complex life cycle that spans both arthropod and mammalian species. In this regard,B. burgdorferimust adapt to various environmental signals, pHs, temperatures, and O2and CO2levels to establish infectious foci. We hypothesize that the BosR protein functions as a global regulator that is required for both borrelial oxidative homeostasis and pathogenesis. To assess the role of BosR inB. burgdorferi, we constructed an IPTG (isopropyl-β-d-thiogalactopyranoside)-regulatedbosRstrain. The selective decrease ofbosRresulted in a change in growth when cells were cultured either anaerobically or microaerobically; however, a distinct growth defect was observed for anaerobically grownB. burgdorferirelative to the growth attenuation observed for microaerobically grownB. burgdorferi.B. burgdorfericells in which BosR levels were reduced were more sensitive to hydrogen peroxide and produced lower levels of NapA (Dps) and SodA, proteins involved in the oxidative stress response. In addition, the levels of OspC and DbpA were also induced coincident with increased BosR levels, suggesting that BosR interfaces with the RpoS regulatory cascade, which is known to modulate virulence gene expression inB. burgdorferi. Taken together, these results indicate that BosR is involved in the resistance ofB. burgdorferito oxidative stressors and affects the expression of genes, either directly or indirectly, whose products are important in borrelial pathogenesis.
An Orally Applicable Shiga Toxin Neutralizer Functions in the Intestine To Inhibit the Intracellular Transport of the Toxin
Authors: Watanabe-Takahashi Miho , Sato Toshio , Dohi Taeko , Noguchi Noriko , Kano Fumi , Murata Masayuki , Hamabata Takashi , Natori Yasuhiro , Nishikawa Kiyotaka
Published: October 2009

Shiga toxin 2 (Stx2) is a major virulence factor in infections with Stx-producing
Escherichia coli
(STEC), which causes gastrointestinal diseases and sometimes fatal systemic complications. Recently, we developed an oral Stx2 inhibitor known as Ac-PPP-tet that exhibits remarkable therapeutic potency in an STEC infection model. However, the precise mechanism underlying the in vivo therapeutic effects of Ac-PPP-tet is unknown. Here, we found that Ac-PPP-tet completely inhibited fluid accumulation in the rabbit ileum caused by the direct injection of Stx2. Interestingly, Ac-PPP-tet accumulated in the ileal epithelial cells only through its formation of a complex with Stx2. The formation of Ac-PPP-tet-Stx2 complexes in cultured epithelial cells blocked the intracellular transport of Stx2 from the Golgi apparatus to the endoplasmic reticulum, a process that is essential for Stx2 cytotoxicity. Thus, Ac-PPP-tet is the first Stx neutralizer that functions in the intestine by altering the intracellular transport of Stx2 in epithelial cells.
Sex differences in force attenuation: a clinical assessment of single-leg hop performance on a portable force plate
Authors: Harrison A D , Ford K R , Myer G D , Hewett T E
Published: October 2009

Objective

Impaired biomechanics and neuromuscular control have been suggested as probable links to female sex bias in the onset of patellofemoral pain syndrome. There are limited objective, clinical measures for assessment of impaired biomechanics and neuromuscular control. The primary objective of this investigation was to examine sex differences in vertical ground reaction force (vGRF) and force loading rate in young athletes performing maximum, repeated vertical single-leg hops (RVSHs). The authors hypothesised that females would demonstrate greater vGRF and force loading rate than males and show interlimb differences in force attenuation.

Design

Cross-sectional study.

Setting

Paediatric sports medicine clinic.

Participants

109 Healthy high school, soccer and basketball athletes.

Assessment of risk factors

Participants performed RVSHs for 15 seconds on a portable force plate with a sampling rate of 400 Hz (Accupower; AMTI, Watertown, Massachusetts, USA).

Main outcome measurements

Raw vGRF was filtered with a generalised cross-validation spline using a 50-Hz cutoff frequency and then normalised to potential energy. Force loading rate was calculated by dividing normalised vGRF by time-to-peak force. Group means were compared using analysis of variance.

Results

The females demonstrated significantly greater normalised vGRF (p<0.001) and force loading rate (p<0.001) during landing than their male counterparts. Neither sex demonstrated significant interlimb differences in force attenuation (p>0.05).

Conclusions

The female athletes may have altered force attenuation capability during RVSHs as identified by increased vGRF and force loading rate compared with the male athletes. Portable force plates may be potential tools to identify altered force attenuation in clinical settings.
Medical complications of an aquatic innovation
Authors: Mountjoy M , Gordon I , McKeown J , Constantini N
Published: October 2009

The sport of swimming has been affected by the innovations of technology with the evolution of the swimsuit. The health benefits of swimming are numerous and are well documented in the scientific literature. As swimming is a low-impact sport, injuries are relatively uncommon. As a direct result of the new swimsuits, team physicians have identified the emergence of a new trend in injury in the aquatic athlete. Extensive blistering and ulceration of the finger tips and distal interphalangeal joints in addition to ecchymoses of the lower limb are now common in the aquatic athlete wearing the new swimsuits. Team physicians working with elite swimmers should be aware of this phenomenon and institute preventive measures.
Violence in youth sports: hazing, brawling and foul play
Authors: Fields S K , Collins C L , Comstock R D
Published: October 2009

By separating hazing, brawling, and foul play and failing to recognise that their connection to sport binds them together into a cohesive subset of sport injury and youth violence, past research has failed to show how sports-related violence is a broad example of interpersonal violence. The acceptance of violence within the sporting culture may, in part, explain why sports-related violence has not yet been widely recognised as a public health concern. This review shows that sports-related violence, including hazing, brawling and foul play, occurs among youth athletes of all ages and in a variety of different sports. The few studies to address this issue have all acknowledged the dangers of sports-related violence; however, no incident tracking method has been developed. Future research must provide accurate national estimates of the incidence of sports-related violence among youth, identify associated risk factors, evaluate preventive interventions and identify effective methods of distributing and implementing evidence-based interventions. Monitoring the magnitude and distribution of the burden of sports-related violence and building the scientific infrastructure necessary to support the development and widespread application of effective sports-related prevention interventions are essential first steps toward a reduction in the incidence of sports-related violence.
A case ofStaphylococcus aureussepticaemia following platelet transfusion
Authors: Coutinho H , Galloway A , Ajdukiewicz K , Cleeve V
Published: October 2009

Platelet transfusions have the highest incidence of post-transfusion sepsis compared with any other blood products.1 Recent reports suggest that platelet-related bacteraemia occurs at a frequency of approximately 50 times greater than that for red blood cells.2 The source is usually skin contaminants from the donor and several organisms have been implicated, the commonest of which are coagulase-negative staphylococci. This report describes a case of seriousStaphylococcus aureussepsis following platelet transfusion, and discusses relevant methods to detect and prevent bacterial contamination of blood products.
Titrimetric immunohistochemical evaluation of DNA hypomethylation in uterine tumours
Authors: Wolk M , Martin J E
Published: October 2009

Background:

Global DNA hypomethylation is a well established feature of many common cancers.

Aims:

To establish a simple semi-quantitative, titrimetric immunohistochemical method in order to exploit this trait for prognostic purposes, in uterine cancers.

Methods:

A monoclonal antibody against 5-methylcytidine was used for immunohistochemical staining of methylated DNA in tumour cells. The degree of methylated DNA in the tumour tissue was visually compared and matched to that of normal tissues stained by serial decreasing concentrations of antibody to 5-methylcytidine.

Results:

Using this method a significant correlation was found between the histological stage and the reduction in DNA methylation in uterine adenocarcinoma (n = 39) and uterine squamous cell carcinoma (n = 23).

Conclusions:

A simple titrimetric immunohistochemical method has been developed for quantitative evaluation of ligands. This method should be further employed in follow-up studies, in order to establish the prognostic value of DNA hypomethylation in uterine cancer.
The clinicopathological significance of BUBR1 overexpression in hepatocellular carcinoma
Authors: Liu A-W , Cai J , Zhao X-L , Xu A-M , Fu H-q , Nian H , Zhang S-H
Published: October 2009

Background and aims:

BUBR1is a key component of the mitotic spindle checkpoint, and its roles in human cancers are controversial and unclear. The aim of this study was to investigate the clinicopathological significance of BUBR1 expression in hepatocellular carcinoma (HCC).

Methods:

The BUBR1 protein and its mRNA levels were measured in 58 HCCs, nine high-grade dysplastic nodules and their paired non-tumorous liver tissues by quantitative real-time polymerase chain reaction (qPCR) and western blot, respectively. In addition, immunochemical analysis of the BUBR1 protein was performed in 458 HCCs and 46 dysplastic nodules, and the clinicopathological significance of the BUBR1 expression was evaluated.

Results:

The BUBR1 expression at both mRNA and protein levels was elevated in two of nine high-grade dysplastic nodules and in 37 of 58 (64%) HCCs. BUBR1 was overexpressed in 207 of 458 (45%) HCCs by immunohistochemistry. Intriguingly, high expression of the BUBR1 was correlated with larger tumour size, higher histological grade, advanced pathological stage, and poor overall and recurrence-free survival. There was a higher frequency of BUBR1 overexpression in cases with positive serum HBsAg than those with negative HBsAg. Moreover, BUBR1 overexpression was associated with P53 staining and high Ki67 labelling indices in HCC tissues.

Conclusions:

BUBR1was overexpressed in about 45% HCCs, and its overexpression may be a relative lately event in HCC progression. Overexpression of BUBR1 was associated with worse prognosis and is a potential prognostic factor for patients with HCC.
Mucosal prolapse syndrome presenting as rectal polyposis
Authors: Brosens L A A , Montgomery E A , Bhagavan B S , Offerhaus G J A , Giardiello F M
Published: October 2009

Mucosal prolapse syndrome comprises a variety of clinical and histopathological entities, with mucosal prolapse as the underlying pathogenic mechanism. Due to variable clinical, endoscopic and histopathological presentation and rareness of symptomatic mucosal prolapse, misdiagnosis resulting in delayed or inappropriate treatment is frequent. This report describes a patient initially diagnosed with a colorectal polyposis syndrome consisting of multiple rectal hyperplastic and adenomatous polyps. But after careful review of medical history and histopathology, the patient was found to have a rare variant of solitary rectal ulcer syndrome presenting as rectal polyposis. The recognition of rectal polyposis as a manifestation of solitary rectal ulcer syndrome/mucosal prolapse syndrome will improve diagnosis and treatment and prevent inappropriate management of this condition.
Approach to a lung transplant biopsy
Authors: Hwang D M , Yousem S A
Published: October 2009

With increasing numbers of lung transplants being performed worldwide, lung transplant allograft biopsies are becoming increasingly common. The evaluation of lung transplant biopsies typically focuses on the assessment of allograft rejection and infection, but other entities may also be seen in biopsy material. Presented here is an approach to lung transplant biopsies, in which there is an overview major diagnostic entities that may be encountered and discussion of findings that may present interpretive challenges.
Signature sequence validation of human papillomavirus type 16 (HPV-16) in clinical specimens
Authors: Lee Sin Hang , Vigliotti Veronica S , Pappu Suri
Published: October 2009

Aims

Persistent infection indicated by detection of human papillomavirus 16 (HPV-16) on repeat testing over a period of time poses the greatest cervical cancer risk. However, variants of HPV-16, HPV-31 and HPV-33 may share several short sequence homologies in the hypervariable L1 gene commonly targeted for HPV genotyping. The purpose of this study was to introduce a robust laboratory procedure to validate HPV-16 detected in clinical specimens, using the GenBank sequence database as the standard reference for genotyping.

Methods

A nested PCR with two pairs of consensus primers was used to amplify the HPV DNA released in crude proteinase K digest of the cervicovaginal cells in liquid-based Papanicolaou cytology specimens. The positive nested PCR products were used for direct automated DNA sequencing.

Results

A 48-base sequence downstream of the GP5+ priming site, or a 34-base sequence upstream thereof, was needed for unequivocal validation of an HPV-16 isolate. Selection of a 45-base, or shorter, sequence immediately downstream of the GP5+ site for Basic Local Alignment Search Tool sequence analysis invariably led to ambiguous genotyping results.

Conclusions

DNA sequence analysis may be used for differential genotyping of HPV-16, HPV-31 and HPV-33 in clinical specimens. However, selection of the signature sequence for Basic Local Alignment Search Tool algorithms is crucial to distinguish certain HPV-16 variants from other closely related HPV genotypes.
A case of chronic fatigue syndrome triggered by influenza H1N1 (swine influenza)
Authors: Vallings Rosamund
Published: October 2009

This case report describes an adolescent boy who was diagnosed as suffering from chronic fatigue syndrome 5 months after infection with H1N1 influenza.
SMALLEST COLOR-SPANNING OBJECT REVISITED
Authors: DAS SANDIP , GOSWAMI PARTHA P. , NANDY SUBHAS C.
Published: October 2009

Given a set of n colored points in IR2 with a total of m (3 ≤ m ≤ n) colors, the problem of identifying the smallest color-spanning object of some predefined shape is studied in this paper. We shall consider two different shapes: (i) corridor and (ii) rectangle of arbitrary orientation. Our proposed algorithm for identifying the smallest color-spanning corridor is simple and runs in O(n2 log n) time using O(n) space. A dynamic version of the problem is also studied, where new points may be added, and the narrowest color-spanning corridor at any instance can be reported in O(mn(α(n))2 log m) time. Our algorithm for identifying the smallest color-spanning rectangle of arbitrary orientation runs in O(n3 log m) time and O(n) space.
LONG-TERM MONITORING OF BRIGHT BLAZARS WITH A DEDICATED CHERENKOV TELESCOPE
Authors: BACKES M. , BECKER J. K. , CLEVERMANN F. , NEISE D. , RHODE W. , ROLLKE S. , POHL M. , RIBORDY M. , RENKER D. , BRETZ T. , MANNHEIM K. , BILAND A. , BRAUN I. , BRITVICH I. , COMMICHAU S. C. , COMMICHAU V. , DORNER D. , GRIMM O. , VON GUNTEN H. , HILDEBRAND D. , KRANICH D. , KRÄHENBÜHL T. , LORENZ E. , LUSTERMANN W. , PAUSS F. , RISSI M. , RÖSER U. , STARK L. S. , VIERTEL G. , WEITZEL Q. , HUBER B. , STRAUMANN U.
Published: October 2009

Flaring activity of Active Galactic Nuclei (AGN) in VHE γ-ray astronomy is observed on timescales from minutes to years and can be explained either by the interaction of relativistic jets with the surrounding material or by imprints of the central engine, like temporal modulation caused by binary systems of supermassive black holes. The key to answer those questions lies in combining 24/7 monitoring with short high sensitivity exposures as provided by the third generation γ-ray astronomy instruments like MAGIC, VERITAS and H.E.S.S. The long-term observations can be provided by a global network of small robotic Cherenkov telescopes.1 As a first step, we are currently setting up a dedicated Cherenkov telescope, which will carry out joint observations with the Whipple 10 m telescope for AGN monitoring. The new telescope will be designed for low costs but high performance by upgrading one of the former HEGRA telescopes, still located at the MAGIC site on the Canary Island of La Palma (Spain). The main novelties will be its robotic operation and a novel camera type, resulting in a greatly improved sensitivity and a lower energy threshold.
THE 2008 MULTIWAVELENGTH CAMPAIGN OF THE TeV RADIO-GALAXY M 87
Authors:   For the H.E.S.S., MAGIC, VERITAS, Chandra and VLBA Collaborations, COLIN PIERRE , BEILICKE MATTHIAS , DAVIES FREDERICK , HARRIS D. E. , HUI C. M. , MAZIN DANIEL , RAUE MARTIN , WAGNER R. M. , WAGNER STEFAN , WALKER R. C.
Published: October 2009

M 87 is the first and brightest radio galaxy detected in the TeV regime. It is the closest extragalactic object showing variability and the only one that does not have its jet pointing toward the line of sight. The structure of the M 87 jet is spatially resolved in X-ray, optical and radio observations. Time correlation between the TeV flux and emission at other wavelengths provides a unique opportunity to localize the VHE emission process occurring in active galaxy nuclei. For 10 years, M87 has been monitored in the TeV band by imaging air Cherenkov telescopes (IACT) as well as in X-ray, optical and radio bands. In 2008, the three main IACTs, H.E.S.S./MAGIC/VERITAS, coordinated their observations in a joint campaign. In February, high TeV activities with rapid flares have been detected. Contemporaneously, M 87 was observed with high resolution instruments in the X-ray (Chandra) and Radio band (VLBA).
BLAZAR PROPERTIES: AN UPDATE FROM RECENT RESULTS
Authors: COSTAMANTE LUIGI
Published: October 2009

After a brief overview of the main properties of blazars, some significant results from recent multiwavelength observations are summarized, in the context of the jet physics.
ON PARTICLE ACCELERATION IN ROTATING AGN FLOWS
Authors: DEMPSEY PAUL , RIEGER FRANK M.
Published: October 2009

Internally rotating jets are expected to be present in a number of astrophysical sources including AGNs. Here we consider the acceleration of energetic charged particles within such flows and discuss the role of shear and centrifugal effects for efficient particle energization. We show that in the case of significant rotation, centrifugal effects could play an important role and facilitate efficient acceleration near the spine of the jet. We point out that shear acceleration could be particularly interesting in the context of hadronic models.
DETECTION OF GAMMA-RAY INDUCED MUONS WITH ANTARES
Authors:   on behalf of the ANTARES Collaboration, ASSIS JESUS ANA CAROLINA
Published: October 2009

This paper presents a gamma-ray down-going induced muon analysis combining the Gamma-ray bursts Coordinates Network (which announces a possible GRB event) with a blind strategy. The goal of this analysis is to find an astrophysical source through the ability of distinguishing between a real alert (signal) and a fake one (background), through comparisons between the position of an Antares event and the position of the alert, leading us to a better understanding of gamma-ray bursts.
EXTENDED SEARCH FOR POINT SOURCES OF NEUTRINOS BELOW AND ABOVE THE HORIZON: COVERING ENERGIES FROM TeV TO EeV WITH ICECUBE
Authors:   for the IceCube Collaboration (See for a full list of authors), LAUER ROBERT
Published: October 2009

Point source searches with neutrino telescopes like IceCube are normally restricted to one hemisphere, due to the selection of up-going events as a way of rejecting the atmospheric muon background. In this work we show that the down-going region above the horizon can be included in the search by suppressing the background through energy-sensitive selection procedures. This approach increases the reach to the EeV regime of the signal spectrum, which was previously not accessible due to the absorption of neutrinos with energies above a PeV inside the Earth. We present preliminary results of this analysis, which for the first time includes up-going as well as down-going muon events in a combined approach. We used data collected with IceCube in a configuration of 22 strings. No significant excess above the atmospheric background is observed. While other analyses provided results for the Northern hemisphere, this new approach extends the field of view to a large part of the southern sky, which was previously not covered with IceCube.
ON ACCELERATION AND PROPAGATION OF ULTRA-HIGH ENERGY COSMIC RAYS
Authors: LEMOINE MARTIN
Published: October 2009

This paper discusses the correlation reported in 2008 by the Pierre Auger Observatory (PAO) of the arrival directions of the highest energy cosmic rays with active galactic nuclei (AGN). It is argued that these correlating AGN do not have the power required to be the sources of ultra-high energy protons. This current PAO dataset is further shown to disfavor giant radio-galaxies (both Fanaroff–Riley type I and II) as sources of ultra-high energy protons. The current data thus likely point to the local large scale structure, in which the actual sources of ultra-high energy cosmic rays camouflage. Finally, it is shown that the last gamma-ray burst in Centaurus A could explain, through rescattering on the Cen A lobes, the apparent cluster of events in this direction.
FERMI LAT OBSERVATIONS OF GAMMA-RAY BURSTS
Authors:   for the Fermi LAT and GBM Collaborations, LONGO F.
Published: October 2009

We present the observations of Gamma-Ray Bursts (GRB) by the Fermi Large Area Telescope (LAT). In the first six months of the mission four GRB were detected at energies greater than 100 MeV by the LAT. The spectral and temporal properties of the three events detected within the LAT field of view, particulary with respect to the low-energy emission detected by the GBM, will be outlined.
ULTRA-HIGH-ENERGY COSMIC RAYS AND PLANCK-SUPPRESSED LORENTZ INVARIANCE VIOLATION
Authors: MACCIONE LUCA , TAYLOR ANDREA M. , MATTINGLY DAVID M. , LIBERATI STEFANO
Published: October 2009

We investigate the consequences of higher dimension Lorentz violating, CPT even kinetic operators that couple standard model fields to a non-zero vector field in an Effective Field Theory framework. Comparing the ultra-high energy cosmic ray spectrum reconstructed in the presence of such terms with data from the Pierre Auger Observatory allows us to establish stringent bounds on O(E/MPl)2suppressed violations of Lorentz invariance.
THE EXTRAGALACTIC BACKGROUND LIGHT: LOWER VERSUS UPPER LIMITS
Authors: RAUE MARTIN
Published: October 2009

The discovery of distant sources of very high energy (VHE) γ-rays with hard energy spectra enabled to derive strong upper limits on the density of the extragalactic background light (EBL). These limits are close to the lower limits derived from deep source counts. A recent re-dertemination of the EBL contribution from resolved sources at 3.6 μm finds a higher EBL density, which is claimed to be in conflict with the assumptions utilized to derive the EBL upper limits from VHE spectra. Here, it is shown that is possible to recover the canonical Γ ~ 1.5 intrinsic spectra for such a higher EBL density.