bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantification of lesion size, depth, and uptake using a dual‐head molecular breast imaging system
Authors: Hruska Carrie B. , O'Connor Michael K.
Published: April 2008

A method to perform quantitative lesion analysis in molecular breast imaging (MBI) was developed using the opposing views from a novel dual‐head dedicated gamma camera. Monte Carlo simulations and phantom models were used to simulate MBI images with known lesion parameters. A relationship between the full widths at 25%, 35%, and of the maximum of intensity profiles through lesions and the true lesion diameter as a function of compressed breast thickness was developed in order to measure lesion diameter. Using knowledge of compressed breast thickness and the attenuation of gamma rays in soft tissue, a method was developed to measure the depth of the lesion to the collimator face. Using the measured lesion diameter and measurements of counts in the lesion and background breast region, relative radiotracer uptake or tumor to background ratio ( ratio) was calculated. Validation of the methods showed that the size, depth, and ratio can be accurately measured for a range of small breast lesions with ratios between 10:1 and 40:1 in breasts with compressed thicknesses between 4 and 10 cm. Future applications of this work include providing information about lesion location in patients for performing a biopsy of site and the development of a threshold for the ratio that can distinguish benign from malignant disease.
Technical Note: Dose‐volume histogram analysis in radiotherapy using the Gaussian error function
Authors: Chow James C. L. , Markel Daniel , Jiang Runqing
Published: April 2008

A mathematical model based on the Gaussian error and complementary error functions was proposed to describe the cumulative dose‐volume histogram (cDVH) for a region of interest in a radiotherapy plan. Parameters in the model (a, b, c) are related to different characteristics of the shape of a cDVH curve such as the maximum relative volume, slope and position of a curve drop off, respectively. A prostate phantom model containing a prostate, the seminal vesicle, bladder and rectum with cylindrical organ geometries was used to demonstrate the effect of interfraction prostate motion on the cDVH based on this error function model. The prostate phantom model was planned using a five‐beam intensity modulated radiotherapy (IMRT), and a four‐field box (4FB), technique with the clinical target volume (CTV) shifted in different directions from the center. In the case of the CTV moving out of the planning target volume (PTV), that is, the margin between the CTV and PTV is underestimated, parameter c (related to position of curve drop off) in the 4FB plan and parameters b (related to the slope of curve) and c in the IMRT plan vary significantly with CTV displacement. This shows that variation of the cDVH is present in the 4FB plan and such variation is more serious in the IMRT plan. These variations of cDVHs for 4FB and IMRT are due to the different dose gradients at the CTV edges in the anterior and posterior directions for the 4FB and IMRT plan. It is believed that a mathematical representation of the dose‐volume relationship provides another viewpoint from which to illustrate problems with radiotherapy delivery such as internal organ motion that affect the dose distribution in a treatment plan.
Adaptive diffusion smoothing: A diffusion‐based method to reduce IMRT field complexity
Authors: Matuszak Martha M. , Larsen Edward W. , Jee Kyung‐Wook , McShan Daniel L. , Fraass Benedick A.
Published: April 2008

Inverse‐planned intensity modulated radiation therapy (IMRT) is often able to achieve complex treatment planning goals that are unattainable with forward three‐dimensional (3D) conformal planning. However, the common use of IMRT has introduced several new challenges. The potentially high degree of modulation in IMRT beams risks the loss of some advantages of 3D planning, such as excellent target coverage and high delivery efficiency. Previous attempts to reduce beam complexity by smoothing often result in plan degradation because the smoothing algorithm cannot distinguish between areas of desirable and undesirable modulation. The purpose of this work is to introduce and evaluate adaptive diffusion smoothing (ADS), a novel procedure designed to preferentially reduce IMRT beam complexity. In this method, a discrete diffusion equation is used to smooth IMRT beams using diffusion coefficients, automatically defined for each beamlet, that dictate the degree of smoothing allowed for each beamlet. This yields a method that can distinguish between areas of desirable and undesirable modulation. The ADS method has been incorporated into our optimization system as a weighted cost function penalty, with two diffusion coefficient definitions designed to promote: (1) uniform smoothing everywhere or (2) smoothing based on cost function gradients with respect to the plan beamlet intensities. The ADS method (with both coefficient types) has been tested in a phantom and in two clinical examples (prostate and head/neck). Both types of diffusion coefficients produce plans with reduced modulation and minimal dosimetric impact, but the cost function gradient‐based coefficients show more potential for reducing beam modulation without affecting dosimetric plan quality. In summary, adaptive diffusion smoothing is a promising tool for ensuring that only the necessary amount of beam modulation is used, promoting more efficient and accurate IMRT planning, QA, and delivery.
Radiobiological Modelling in Radiation Oncology
Authors: Warkentin Brad
Published: April 2008

Radiobiological Modelling in Radiation Oncology Dale Roger and Jones Bleddyn The British Institute of Radiology, London, UK, 2007. publications@bir.org.uk, £60.0. ISBN: 9780905749600.
Bats Limit Insects in a Neotropical Agroforestry System
Authors: Williams-Guillén Kimberly , Perfecto Ivette , Vandermeer John
Published: April 2008

Exclosure experiments have demonstrated the effects of bird predation on arthropods. In a Mexican coffee plantation, we excluded foliage-gleaning bird and bat predators from coffee plants. Effects of bats and birds were additive. In the dry season, birds reduced arthropods in coffee plants by 30%; birds and bats together reduced arthropods by 46%. In the wet season, bats reduced arthropods by 84%, whereas birds reduced them by only 58%. We conclude that previous "bird" exclosure experiments may have systematically underestimated the effects of bats.
Aztec Arithmetic Revisited: Land-Area Algorithms and Acolhua Congruence Arithmetic
Authors: Williams Barbara J. , Jorge y Jorge María del Carmen
Published: April 2008

Acolhua-Aztec land records depicting areas and side dimensions of agricultural fields provide insight into Aztec arithmetic. Hypothesizing that recorded areas resulted from indigenous calculation, in a study of sample quadrilateral fields we found that 60% of the area values could be reproduced exactly by computation. In remaining cases, discrepancies between computed and recorded areas were consistently small, suggesting use of an unknown indigenous arithmetic. In revisiting the research, we discovered evidence for the use of congruence principles, based on proportions between the standard linear Acolhua measure and their units of shorter length. This procedure substitutes for computation with fractions and is labeled “Acolhua congruence arithmetic.” The findings also clarify variance between Acolhua and Tenochca linear units, long an issue in understanding Aztec metrology.
The Electrical Conductivity of Post-Perovskite in Earth's D'' Layer
Authors: Ohta Kenji , Onoda Suzue , Hirose Kei , Sinmyo Ryosuke , Shimizu Katsuya , Sata Nagayoshi , Ohishi Yasuo , Yasuhara Akira
Published: April 2008

Recent discovery of a phase transition from perovskite to post-perovskite suggests that the physical properties of Earth's lowermost mantle, called the D″ layer, may be different from those of the overlying mantle. We report that the electrical conductivity of (Mg
0.9
Fe
0.1
)SiO
3
post-perovskite is >10
2
siemens per meter and does not vary greatly with temperature at the conditions of the D″ layer. A post-perovskite layer above the core-mantle boundary would, by electromagnetic coupling, enhance the exchange of angular momentum between the fluid core and the solid mantle, which can explain the observed changes in the length of a day on decadal time scales. Heterogeneity in the conductivity of the lowermost mantle is likely to depend on changes in chemistry of the boundary region, not fluctuations in temperature.
Bacteria Subsisting on Antibiotics
Authors: Dantas Gautam , Sommer Morten O. A. , Oluwasegun Rantimi D. , Church George M.
Published: April 2008

Antibiotics are a crucial line of defense against bacterial infections. Nevertheless, several antibiotics are natural products of microorganisms that have as yet poorly appreciated ecological roles in the wider environment. We isolated hundreds of soil bacteria with the capacity to grow on antibiotics as a sole carbon source. Of 18 antibiotics tested, representing eight major classes of natural and synthetic origin, 13 to 17 supported the growth of clonal bacteria from each of 11 diverse soils. Bacteria subsisting on antibiotics are surprisingly phylogenetically diverse, and many are closely related to human pathogens. Furthermore, each antibiotic-consuming isolate was resistant to multiple antibiotics at clinically relevant concentrations. This phenomenon suggests that this unappreciated reservoir of antibiotic-resistance determinants can contribute to the increasing levels of multiple antibiotic resistance in pathogenic bacteria.
Comparison of Nasal Swabs with Nose Blowing for Community-Based Pneumococcal Surveillance of Healthy Children
Authors: Leach Amanda Jane , Stubbs Elizabeth , Hare Kim , Beissbarth Jemima , Morris Peter Stanley
Published: April 2008

The nasopharynx (NP) is the preferred site for detection of
Streptococcus pneumoniae
in young children, but NP sampling is not well tolerated. We compared nose blowing with paired nasal swabs. The sensitivity of nose blowing was 46% (95% confidence interval [CI] 38 to 56%), which increased to 94% (95% CI, 85 to 98%) for children with visible secretions.
Evaluation of Novel Broad-Range Real-Time PCR Assay for Rapid Detection of Human Pathogenic Fungi in Various Clinical Specimens
Authors: Vollmer Tanja , Störmer Melanie , Kleesiek Knut , Dreier Jens
Published: April 2008

In the present study, a novel broad-range real-time PCR was developed for the rapid detection of human pathogenic fungi. The assay targets a part of the 28S large-subunit ribosomal RNA (rDNA) gene. We investigated its application for the most important human pathogenic fungal genera, including
Aspergillus, Candida, Cryptococcus, Mucor, Penicillium, Pichia, Microsporum, Trichophyton
, and
Scopulariopsis
. Species were identified in PCR-positive reactions by direct DNA sequencing. A noncompetitive internal control was applied to prevent false-negative results due to PCR inhibition. The minimum detection limit for the PCR was determined to be one 28S rDNA copy per PCR, and the 95% detection limit was calculated to 15 copies per PCR. To assess the clinical applicability of the PCR method, intensive-care patients with artificial respiration and patients with infective endocarditis were investigated. For this purpose, 76 tracheal secretion samples and 70 heart valve tissues were analyzed in parallel by real-time PCR and cultivation. No discrepancies in results were observed between PCR analysis and cultivation methods. Furthermore, the application of the PCR method was investigated for other clinical specimens, including cervical swabs, nail and horny skin scrapings, and serum, blood, and urine samples. The combination of a broad-range real-time PCR and direct sequencing facilitates rapid screening for fungal infection in various clinical specimens.
Is the Sequenced
Bordetella pertussis
Strain Tohama I Representative of the Species?
Authors: Caro Valérie , Bouchez Valérie , Guiso Nicole
Published: April 2008

Subtractive hybridization was carried out to identify differences between the sequenced genome of
Bordetella pertussis
Tohama I and those of two recently collected isolates. We identified genetic regions specific to recent isolates, old isolates, and isolates of
B. parapertussis
and
B. bronchiseptica
species. We conclude that Tohama I strain is not representative of the
B. pertussis
species.
West Nile Virus Entry Requires Cholesterol-Rich Membrane Microdomains and Is Independent of αvβ3 Integrin
Authors: Medigeshi Guruprasad R. , Hirsch Alec J. , Streblow Daniel N. , Nikolich-Zugich Janko , Nelson Jay A.
Published: April 2008

West Nile virus (WNV) has been the leading cause of viral encephalitis in the United States since 1999. The endocytic processes involved in the internalization of infectious WNV by various cell types are not well characterized, and the involvement of cholesterol-rich membrane microdomains, or lipid rafts, in the life cycle of WNV has not been investigated previously. In this study, we found that the depletion of cellular cholesterol levels by brief treatment with methyl-β-cyclodextrin resulted in a 100-fold reduction of the titers of infectious WNV released into the culture supernatant, as well as a reduction in the number of WNV genome copies in the cholesterol-depleted cells. The addition of exogenous cholesterol to cholesterol-depleted cells reversed this effect. Cholesterol depletion postinfection did not affect WNV growth, suggesting that the effect occurs at the level of WNV entry. We also showed that while WNV entry did not require αvβ3 integrin and focal adhesion kinase, WNV particles failed to be internalized by cholesterol-depleted cells. Finally, we showed the colocalization of the WNV envelope protein and cholera toxin B, which is internalized in a lipid raft-dependent pathway, in microdomain clusters at the plasma membrane. These data suggest that WNV utilizes lipid rafts during initial stages of internalization and that the lipid rafts may contain a factor(s) that may enhance WNV endocytosis.
Characterization of a Rhesus Monkey Calicivirus Representing a New Genus of
Caliciviridae
Authors: Farkas Tibor , Sestak Karol , Wei Chao , Jiang Xi
Published: April 2008

In this study, we report the characterization of a novel calicivirus (CV), the Tulane virus (TV), which was isolated from stool samples of captive juvenile rhesus macaques (
Macaca mulatta
) of the Tulane National Primate Research Center. The complete genome of TV contains 6,714 nucleotides plus a poly(A) tail and is organized into three open reading frames (ORFs) that encode the nonstructural (NS) polyprotein (ORF1); the capsid protein (ORF2), with an estimated molecular mass of 57.9 kDa; and a possible minor structural protein (ORF3), with an isoelectric point (pI) of 10.0 and a calculated molecular mass of 22.8 kDa. The NS polyprotein revealed all typical CV amino acid motifs, including GXXGXGKT (NTPase), EYXEX (Vpg), GDCG (protease), and GLPSG and YGDD (polymerase). Phylogenetic trees constructed for the NS polyprotein, NTPase, protease, polymerase, and capsid protein sequences consistently placed the TV on a branch rooted with
Norovirus
, but with distances equal to those between other genera. The TV can be cultured in a monkey kidney cell line (LLC-MK2) with the appearance of typical cytopathic effect. TV exhibits a typical CV morphology, with a diameter of 36 nm, and has a buoyant density of 1.37 g/ml. According to these physicochemical and genetic characteristics, TV represents a new CV genus for which we propose the name “Recovirus” (rhesus enteric CV). Although the pathogenicity of TV in rhesus macaques remains to be elucidated, the likelihood of TV causing intestinal infection and the availability of a tissue culture system make this virus a valuable surrogate for human CVs.
Characterization of the Follicular Dendritic Cell Reservoir of Human Immunodeficiency Virus Type 1
Authors: Keele Brandon F. , Tazi Loubna , Gartner Suzanne , Liu Yiling , Burgon Trever B. , Estes Jacob D. , Thacker Tyler C. , Crandall Keith A. , McArthur Justin C. , Burton Gregory F.
Published: April 2008

Throughout the natural course of human immunodeficiency virus (HIV) infection, follicular dendritic cells (FDCs) trap and retain large quantities of particle-associated HIV RNA in the follicles of secondary lymphoid tissue. We have previously found that murine FDCs in vivo could maintain trapped virus particles in an infectious state for at least 9 months. Here we sought to determine whether human FDCs serve as an HIV reservoir, based on the criteria that virus therein must be replication competent, genetically diverse, and archival in nature. We tested our hypothesis using postmortem cells and tissues obtained from three HIV-infected subjects and antemortem blood samples obtained from one of these subjects. Replication competence was determined using coculture, while genetic diversity and the archival nature of virus were established using phylogenetic and population genetics methods. We found that FDC-trapped virus was replication competent and demonstrated greater genetic diversity than that of virus found in most other tissues and cells. Antiretrovirus-resistant variants that were not present elsewhere were also detected on FDCs. Furthermore, genetic similarity was observed between FDC-trapped HIV and viral species recovered from peripheral blood mononuclear cells obtained 21 and 22 months antemortem, but was not present in samples obtained 4 and 18 months prior to the patient's death, indicating that FDCs can archive HIV. These data indicate that FDCs represent a significant reservoir of infectious and diverse HIV, thereby providing a mechanism for viral persistence for months to years.
Demyelinating and Nondemyelinating Strains of Mouse Hepatitis Virus Differ in Their Neural Cell Tropism
Authors: Das Sarma Jayasri , Iacono Kathryn , Gard Lilli , Marek Ryan , Kenyon Lawrence C. , Koval Michael , Weiss Susan R.
Published: April 2008

Some strains of mouse hepatitis virus (MHV) can induce chronic inflammatory demyelination in mice that mimics certain pathological features of multiple sclerosis. We have examined neural cell tropism of demyelinating and nondemyelinating strains of MHV in order to determine whether central nervous system (CNS) cell tropism plays a role in demyelination. Previous studies demonstrated that recombinant MHV strains, isogenic other than for the spike gene, differ in the extent of neurovirulence and the ability to induce demyelination. Here we demonstrate that these strains also differ in their abilities to infect a particular cell type(s) in the brain. Furthermore, there is a correlation between the differential localization of viral antigen in spinal cord gray matter and that in white matter during acute infection and the ability to induce demyelination later on. Viral antigen from demyelinating strains is detected initially in both gray and white matter, with subsequent localization to white matter of the spinal cord, whereas viral antigen localization of nondemyelinating strains is restricted mainly to gray matter. This observation suggests that the localization of viral antigen to white matter during the acute stage of infection is essential for the induction of chronic demyelination. Overall, these observations suggest that isogenic demyelinating and nondemyelinating strains of MHV, differing in the spike protein expressed, infect neurons and glial cells in different proportions and that differential tropism to a particular CNS cell type may play a significant role in mediating the onset and mechanisms of demyelination.
Multimerization of Tegument Protein pp28 within the Assembly Compartment Is Required for Cytoplasmic Envelopment of Human Cytomegalovirus
Authors: Seo Jun-Young , Britt William J.
Published: April 2008

Human cytomegalovirus (HCMV) UL99-encoded pp28 is an essential tegument protein required for envelopment and production of infectious virus. Nonenveloped virions accumulate in the cytoplasm of cells infected with recombinant viruses with the UL99 gene deleted. Previous results have suggested that a key function of pp28 in the envelopment of infectious HCMV is expressed after the protein localizes in the assembly compartment (AC). In this study, we investigated the potential role of pp28 multimerization in the envelopment of the infectious virion. Our results indicated that pp28 multimerized during viral infection and that interacting domains responsible for self-interaction were localized in the amino terminus of the protein (amino acids [aa] 1 to 43). The results from transient-expression and/or infection assays indicated that the self-interaction took place in the AC. A mutant pp28 molecule containing only the first 35 aa failed to accumulate in the AC, did not interact with pp28 in the AC, and could not support virus replication. In contrast, the first 50 aa of pp28 was sufficient for the self-interaction within the AC and the assembly of infectious virus. Recombinant viruses encoding an in-frame deletion of aa 26 to 33 of pp28 were replication competent, whereas infectious virus was not recovered from HCMV BACs lacking aa 26 to 43. These findings suggested that the accumulation of pp28 was a prerequisite for multimerization of pp28 within the AC and that pp28 multimerization in the AC represented an essential step in the envelopment and production of infectious virions.
Plasmacytoid Dendritic Cell Dynamics and Alpha Interferon Production during Simian Immunodeficiency Virus Infection with a Nonpathogenic Outcome
Authors: Diop Ousmane M. , Ploquin Mickaël J.-Y. , Mortara Lorenzo , Faye Abdourahmane , Jacquelin Béatrice , Kunkel Désirée , Lebon Pierre , Butor Cécile , Hosmalin Anne , Barré-Sinoussi Françoise , Müller-Trutwin Michaela C.
Published: April 2008

We addressed the role of plasmacytoid dendritic cells (PDC) in protection against AIDS in nonpathogenic simian immunodeficiency virus (SIVagm) infection in African green monkeys (AGMs). PDC were monitored in blood and lymph nodes (LNs) starting from day 1 postinfection. We observed significant declines in blood during acute infection. However, PDC then returned to normal levels, and chronically infected AGMs showed no decrease of PDC in blood. There was a significant increase of PDC in LNs during acute infection. Blood PDC displayed only weak alpha interferon (IFN-α) responses to TLR9 agonist stimulation before infection. However, during acute infection, both blood and LN PDC showed a transiently increased propensity for IFN-α production. Bioactive IFN-α was detected in plasma concomitant with the peak of viremia, though levels were only low to moderate in some animals. Plasma interleukin 6 (IL-6) and IL-12 were not increased. In conclusion, PDC were recruited to the LNs and displayed increased IFN-α production during acute infection. However, increases in IFN-α were transient. Together with the lack of inflammatory cytokine responses, these events might play an important role in the low level of T-cell activation which is associated with protection against AIDS in nonpathogenic SIVagm infection.
Paucity of CD4
+
CCR5
+
T Cells May Prevent Transmission of Simian Immunodeficiency Virus in Natural Nonhuman Primate Hosts by Breast-Feeding
Authors: Pandrea Ivona , Onanga Richard , Souquiere Sandrine , Mouinga-Ondéme Augustin , Bourry Olivier , Makuwa Maria , Rouquet Pierre , Silvestri Guido , Simon François , Roques Pierre , Apetrei Cristian
Published: April 2008

Simian immunodeficiency virus (SIV) persistence in wild populations of African nonhuman primates (NHPs) may occur through horizontal and vertical transmission. However, the mechanism(s) and timing of the latter type of transmission have not been investigated to date. Here we present the first study of SIV transmissibility by breast-feeding in an African NHP host. Six mandrill dames were infected with plasma containing 300 50% tissue culture infective doses of SIVmnd-1 on the day after delivery. All female mandrills became infected, as demonstrated by both plasma viral loads (VLs) and anti-SIVmnd-1 seroconversion. Neither fever nor lymphadenopathy was observed. At the peak of SIVmnd-1 viral replication (days 7 to 10 postinoculation), plasma VLs were high (8 × 10
6
to 8 × 10
8
RNA copies/ml) and paralleled the high VLs in milk (4.7 × 10
4
to 5.6 × 10
5
RNA/ml). However, at the end of the breast-feeding period, after 6 months of follow-up, no sign of infection was observed for the offspring. Later on, during a 4-year follow-up examination, two of the offspring showed virological evidence of SIVmnd-1 infection. Both animals seroconverted at least 6 months after the interruption of lactation. In conclusion, despite extensive viral replication in mandrill mothers and high levels of free virus in milk, no SIVmnd-1 transmission was detectable at the time of breast-feeding or during the following months. Since we observed a markedly lower expression of CCR5 on the CD4
+
T cells of young mandrills and African green monkeys than on those of adults, we propose that low levels of this viral coreceptor on CD4
+
T cells may be involved in the lack of breast-feeding transmission in natural hosts of SIVs.
Natural Resistance of Human Immunodeficiency Virus Type 1 to the CD4bs Antibody b12 Conferred by a Glycan and an Arginine Residue Close to the CD4 Binding Loop
Authors: Duenas-Decamp Maria José , Peters Paul , Burton Dennis , Clapham Paul R.
Published: April 2008

The human monoclonal antibody b12 recognizes a conserved epitope on gp120 that overlaps the CD4 binding site. b12 has neutralizing activity against diverse human immunodeficiency virus type 1 (HIV-1) strains. However, we recently reported that b12 sensitivity of HIV-1 envelopes amplified from patient tissues without culture varied considerably. For two subjects, there was clear modulation of b12 sensitivity, with lymph node-derived envelopes being essentially resistant while those from brain tissue were sensitive. Here, we have mapped envelope determinants of b12 resistance by constructing chimeric envelopes from resistant and sensitive envelopes derived from lymph node and brain tissue, respectively. Residues on the N-terminal flank of the CD4 binding loop conferred partial resistance. However, a potential glycosylation site at residue N386 completely modulated b12 resistance but required the presence of an arginine at residue 373. Moreover, the introduction of R373 into b12-sensitive NL4.3 and AD8 envelopes, which carry N386, also conferred b12 resistance. Molecular modeling suggests that R373 and the glycan at N386 may combine to sterically exclude the benzene ring of b12 W100 from entering a proximal pocket. In summary, we identify residues on either side of the CD4 binding loop that contribute to b12 resistance in immune tissue in vivo. Our data have relevance for the design of vaccines that aim to elicit neutralizing antibodies.
Transformation by Bovine Papillomavirus Type 1 E6 Requires Paxillin
Authors: Wade Ramon , Brimer Nicole , Vande Pol Scott
Published: April 2008

Papillomavirus E6 proteins are adapters that change the function of cellular regulatory proteins. The bovine papillomavirus type 1 E6 (BE6) binds to LXXLL peptide sequences termed LD motifs (consensus sequence LDXLLXXL) on the cellular protein paxillin that is a substrate of Src and focal adhesion kinases. Anchorage-independent transformation induced by BE6 required both paxillin and BE6-binding LD motifs on paxillin but was independent of the major tyrosine phosphorylation sites of paxillin. The essential role of paxillin in transformation by BE6 highlights the role of paxillin in the transduction of cellular signals that result in anchorage-independent cell proliferation.
Are the take-off and landing phase dynamics of the volleyball spike jump related to patellar tendinopathy?
Authors: Bisseling R W , Hof A L , Bredeweg S W , Zwerver J , Mulder T
Published: April 2008

Objective:

The causal mechanism of the chronic sports injury patellar tendinopathy is not well understood. The aim of the present study was to compare ankle and knee joint dynamics during the performance of the volleyball spike jump between healthy volleyball players (n = 8) and asymptomatic volleyball players with previous patellar tendinopathy (n = 7).

Design:

Cross-sectional.

Methods:

Inverse dynamics were used to estimate ankle and knee joint dynamics. From these multiple biomechanical variables, a logistic regression was performed to estimate the probability of the presence or absence of previous patellar tendinopathy among the volleyball players studied.

Results:

Several biomechanical variables improved the prediction of the presence or absence of previous patellar tendinopathy. For landing, ankle plantar flexion at the time of touch-down, and knee range of motion during the first part of impact, and for take-off, loading rate of the knee extensor moment during the eccentric countermovement phase of take-off were predictive. As interaction effects, the presence or absence of previous patellar tendinopathy were correctly predicted by ankle and knee range of motion during the first part of impact, by loading rate of the knee extensor moment during the eccentric phases of take-off and landing, and by knee angular velocity during the eccentric phases of take-off and landing.

Conclusion:

Smaller joint flexion during the first part of landing impact , and higher rate of knee moment development during the eccentric phases of the spike-jump landing sequence, together with higher knee angular velocities, might be risk factors in the development of patellar tendinopathy in volleyball players.
MRI evaluation of body composition changes in wrestlers undergoing rapid weight loss
Authors: Kukidome T , Shirai K , Kubo J , Matsushima Y , Yanagisawa O , Homma T , Aizawa K
Published: April 2008

Purpose:

Changes in body composition of college wrestlers undergoing rapid weight reduction were evaluated over time using magnetic resonance imaging (MRI).

Methods:

This study evaluated 12 wrestlers (male, 18–22 years of age) who participated in Japan’s 2005 intercollegiate wrestling tournament. For this study, MRI (of the right femoral region and the trunk), as well as measurements of body weight, body fat percentage and body water content, were performed 1 month and 1 week prior to the weigh-in, on the day of the weigh-in, on the day of the match (after the match), and 1 week after the weigh-in. A survey of food and fluid intake was also conducted.

Results:

Several variables were significantly lower on the day of the weigh-in than one month prior: body weight (p<0.01, −7.3% (SD 1.6%)); body fat (p<0.05, −9.3 (5.8)%); body water content (p<0.01, −5.9 (1.6)%); trunk cross-section (p<0.01, −13.2 (4.4)%), including separate measurements of trunk viscera, trunk muscle, and trunk fat; quadriceps muscle; lower subcutaneous; and food intake (p<0.01, 122 (20)). At 1 week after the match, all metrics had recovered to their levels measured 1 month before the weigh-in. Certain variables that were highly sensitive to hydration recovered more rapidly: they had reached their initial levels when measured immediately after the match.

Conclusion:

Rapid weight reduction reduced the wrestlers’ cross-sectional areas of muscle and fat tissues, which tended to recover through rehydration after the weigh-in. These results suggest that rapid weight reduction of wrestlers induced changes in different regions of the body.
Epidemiology of cervical spine abnormalities in asymptomatic adult professional rugby union players using static and dynamic MRI protocols: 2002 to 2006
Authors: Castinel B H , Adam P , Milburn P D , Castinel A , Quarrie K L , Peyrin J-C , Yeo J D
Published: April 2008

Objective

In this study, the prevalence of abnormalities in the cervical spine of asymptomatic professional rugby players using both static and dynamic magnetic resonance imaging (MRI) in order to improve the detection of abnormalities and prevention of related injuries was investigated.

Design

Prospective observational study.

Setting

French professional rugby union clubs, between 2002 and 2006.

Participants

206 elite male adult players.

Intervention

Static sagittal T2 and axial T2* fast spin echo (FSE), and dynamic sagittal single-shot FSE weighted MRI scans of the C2–C7 region were examined for the presence of abnormalities. Participants’ spines were in supine neutral position for the static protocol but were allowed complete flexibility in a sagittal plane for the dynamic protocol.

Main outcome measurements

The medulla-to-canal ratio (MCR) was measured at every vertebral disc level for both MRI methods. When observed, anatomical abnormalities were categorised.

Results

Anatomical abnormalities mainly consisted of degenerative discopathy and were most frequently observed in players aged>21 years, as well as in players whose MCR was abnormally high based on medical expertise. Most MCRs that were initially assessed as intermediate with static MRI were subsequently assessed as abnormal with dynamic MRI assessment.

Conclusions

Since dynamic MRI is more accurate than static techniques in examining the cervical spine, it contributes substantially to identifying the risk of spinal injuries in professional rugby players, and when used in association with clinical assessment, it can assist in preventing spinal injury.
National study of physical and sexual assault among women with disabilities
Authors: Casteel C , Martin S L , Smith J B , Gurka K K , Kupper L L
Published: April 2008

Objective:

To examine the association between the level of disability impairment and physical and sexual assault in a sample of US women at least 18 years of age.

Design, setting and participants:

Retrospective longitudinal study of 6273 non-institutionalized US women from 8000 women participating in the 1995–1996 National Violence Against Women (NVAW) Survey.

Main outcome measure:

Women’s experiences of physical and sexual assault in the 12 months before the NVAW interview.

Results:

Most women reported having no disability (n = 5008, 79.8%) and/or not experiencing an assault in the year before their interview (n = 6018, 95.9%). Less than 5% (n = 280) reported having a disability that severely limited daily activities, and 15.7% (n = 985) reported having a disability that moderately limited activities. Less than 4% (n = 218) of the women reported a physical-only assault, and less than 1% (n = 37) reported being sexually assaulted. Women with severe disability impairments were four times more likely to be sexually assaulted than women with no reported disabilities (RR = 4.0, 95% CI 1.5 to 10.6). Little difference in the risk of sexual assault was found between women with moderate disability impairments and those reporting no disabilities (RR = 1.0, 95% CI 0.3 to 2.8). Women with severe (RR = 1.6, 95% CI 0.9 to 3.0) and moderate (RR = 1.2, 95% CI 0.8 to 1.9) disability impairments were at greater risk, although not quite significantly so, of physical-only assault than were women without a disability.

Conclusion:

The findings suggest that women with disabilities that severely limit activities of daily living are at increased risk of sexual assault.
Unintentional pediatric submersion-injury-related hospitalizations in the United States, 2003
Authors: Cohen R H , Matter K C , Sinclair S A , Smith G A , Xiang H
Published: April 2008

The objective of this study was to examine the demographic characteristics and hospital resource utilization of submersion-injury-related hospitalizations among persons ⩽20 years of age in the USA in 2003. All 1475 pediatric submersion-injury-related hospital discharges in the Kids’ Inpatient Database were identified by ICD-9-CM diagnosis code or external cause of injury code. These cases represent an estimated 2490 pediatric submersion-injury-related hospitalizations nationwide. Inpatient costs for these estimated hospitalizations were ∼$10 million. The overall pediatric submersion-injury-related rate of hospitalization was 3.0 per 100 000 persons. Children aged 0–4 years had the highest rate of hospitalization (7.7 per 100 000 persons). Children with permanent submersion-injury-related morbidity accounted for 5.8% of hospital admissions and 37.3% of hospital costs in our study, and children with submersion-injury-related in-hospital death accounted for 11.6% of hospital admissions and 20.0% of hospital costs in our study. Prevention of submersion injury using focused, proven strategies deserves increased attention.
Clustered and missing data in the US National Trauma Data Bank: implications for analysis
Authors: Roudsari B , Field C , Caetano R
Published: April 2008

Background:

Injury researchers are increasingly using the US National Trauma Data Bank (NTDB). However, there are some methodological issues that might threaten the validity of studies that use this database for injury research.

Methods:

Two methodological issues were evaluated: clustering of patients within trauma centers and missing data. To illustrate how these issues might affect the results of a study, the following four analytical approaches that evaluated the association between patients’ blood alcohol concentration (BAC) in the emergency department (ED), patients’ resource utilization, and ED or hospital disposition were compared: (A) deleting subjects with missing BAC and ignoring clustering of patients within trauma centers; (B) deleting subjects with missing BAC while taking into account clustering; (C) using imputed values for patients’ BAC and ignoring the clustering issue; (D) using the imputed data while taking into account clustering.

Results:

Adjustment for clustering of patients within trauma centers increased the CIs in models B and D. The results of the analyses based on imputed data showed that estimates based on complete case analysis were biased. For example, the odds ratio for the use of a head CT scan fell from 1.84 (95% CI 1.49 to 2.28) in approach B to 1.26 (95% CI 0.98 to 1.64) in approach D.

Conclusions:

Excluding patients with missing values for BAC in studies that evaluate the association between this variable and patients’ resource utilization and ED or hospital disposition, using the NTDB, led to biased estimates. Furthermore, ignoring the clustering design led to artificially narrow CIs.
Using online databases to find journal articles on injury prevention and safety promotion research: key journals and the databases that index them
Authors: Lawrence D W , Laflamme L
Published: April 2008

Objectives:

(1) To determine the trends of the number of journals that publish injury prevention and safety promotion (IPSP) articles and the number of articles published each year from 1900 through 2006; (2) to determine the coverage of key IPSP journals in widely used literature databases.

Methods:

Journals were identified through a structured procedure that included hand-searching selected classification categories of two major listings of periodicals that publish four or more IPSP-relevant articles per year. Article relevance was assessed using the inclusion criteria for SafetyLit (a database of scholarly literature selected for its relevance to the IPSP field). Each identified journal was hand-searched from its first issue, and IPSP-relevant articles were added to the SafetyLit archive database. A MySQL database was used to perform basic queries and statistical summary analyses for journals published 1900–2006. The number of IPSP journals and journal articles was plotted for these years to identify publication trends. The publication year range of each IPSP journal was compared with the coverage, if any, of the journals in each of the five databases.

Results:

Of the 17 839 journals assessed, 597 met the threshold for inclusion in this study. This amounts to thousands of IPSP-related articles published each year: 6100 in 2006. Only 160 (26.8%) of the journals are included in all five databases, and none have all publication years included in all of the databases.

Conclusions:

Some key IPSP journals are completely excluded from some of the databases. Thus, a search in a single database may miss key information from one of the many disciplines that publish IPSP-relevant information.
Xenotypa Petrak and Graphostroma gen. nov., segregates from Diatrypaceae
Authors: Pirozynski K. A.
Published: April 2008

A common North American fungus resembling Diatrype stigma (Hoffm. ex Fr.) Fr. and previously described under several epithets in the Diatrypaceae is placed in Graphostroma, a new monotypic genus of Xylariaceae, as G. platystoma (Schw.) comb. nov. It is compared with the European Xenotypa aterrima (Fr.) Petrak, representing another monotypic genus segregated from the Diatrypaceae and belonging in the Diaporthaceae.
Evidence for silicon as a prevalent elemental component in pollen wall structure
Authors: Crang Richard E. , May Georgiana
Published: April 2008

Lychnis alba pollen possesses 0.73–0.79% elemental silicon (dry weight), and levels at least as high as in pollen exines have been indicated in tapetal orbicules upon maturation. Even higher levels of elemental silicon (1.30–1.37%) were recorded from Impatiens sultanii pollen. This may indicate that silicon is an important elemental component of exine materials characteristic of many types of pollen, in which silicate compounds may aid in the high degree of pollen resistance to geological weathering, microbial decay, and acetolysis treatments. Further, the data for the incorporation of silicon in L. alba pollen in this report support the concept that exine materials are derived from tapetal cell secretions during pollen ontogeny.
Studies on the infection of Norway spruce roots by Heterobasidion annosum
Authors: Asiegbu Frederick , Daniel Geoffrey , Johansson Martin
Published: April 2008

The interaction between the root rot fungus (Heterobasidion annosum) and seedling roots of Norway spruce was studied using scanning and transmission electron microscopy, light microscopy, and immunohistochemistry. Results showed that attachment to root surface and penetration of root epidermal walls were facilitated using pregerminated conidiospores as inocula. High inoculum concentrations (107 spores/mL) were also required for rapid colonization and establishment of the pathogen in the cortex. At lower spore concentrations, fewer hyphae were detected within the cortical region. The induction of hypersensitive response was a function of both time and spore concentration. Formation of infective structures on the root surface was evident 24 h after inoculation. Internal colonization of cortical tissues started 24–48 h postinoculation and reached the endodermis within 72 h. Severe destruction of stelar cells was observed 12 – 15 d postinfection. Cell invasion by the pathogen was correlated with formation of papillae and lignification in cortical cells. Increases in the enzymatic activity of defence-related proteins (chitinase and peroxidase) of infected roots were also evident. When vascular tissues were severely damaged disruption of endodermal cells was also recorded using light microscopy. The presence of H. annosum antigenic materials within cell wall boundaries suggests intercellular penetration by the pathogen. Key words: Norway spruce, Heterobasidion annosum, histochemistry, immunofluorescence, chitinase, peroxidase.
Seed banks of forested and disturbed soils in southwestern British Columbia
Authors: McGee Ann , Feller M. C.
Published: April 2008

The species composition and density of seed banks in the forest floors and mineral soils of several undisturbed (immature, midseral forests) and disturbed (transmission line rights-of-way) ecosystems in southwestern British Columbia were estimated using the seedling-emergence method. The total soil surface area sampled was 9.4 m2. Germination behaviour of seven dominant species in response to depth of burial and substrate was also studied in a greenhouse experiment. A total of 16 289 seedlings germinated, representing 62 native and naturalized vascular plant species and several unidentified grass species. Most seedlings emerged from the forest floor, and the number of germinants generally decreased with increasing sample depth. Drier ecosystems had the lowest number and density of germinants. Burial depth significantly affected germination of all species tested. Mineral soil was equal, or superior, to forest floor as a germination substrate for all species tested. Depth–substrate interactions for several species indicated that the pattern of influence of burial depth in relation to substrate varied with species. Caution is urged extrapolating greenhouse seed-bank studies to potential weed populations in the field. Establishment of species from the seed bank will be a function of the depth to which the soil is disturbed and the kind of disturbance (burning, scarification) imposed. Key words: British Columbia, Coastal Western Hemlock zone, seed bank, seed germination, seed diversity, seed density.
Measurement of heat injury in plant tissue by using electrical impedance analysis
Authors: Zhang M. I. N. , Willison J. H. M. , Cox M. A. , Hall S. A.
Published: April 2008

Electrical impedance spectra (100 Hz to 800 kHz) were measured in pieces of potato (Solanum tuberosum L.) tuber tissue that had been heat stressed. Analysis of the impedance data based on equivalent circuits showed that tissue injury was revealed as decreases in membrane capacitance and extracellular resistance. By using a single piece of tissue, membrane thermostability (in relation to heat stress temperature or time of heat stress) was measured. Nonstressful temperature changes produced changes in tissue parameters that were fully reversible when the direction of temperature change was reversed. Stressful temperature changes produced irreversible changes in parameters. During heat injury, decrease in extracellular resistance always preceded a decrease in tonoplast capacitance. It is suggested that two stages may be involved in heat injury to membranes: functional injury leading to electrolyte leakage to extracellular space, and structural damage leading to membrane disintegration. It is concluded that electrical impedance analysis is useful in plant heat stress physiology. Key words: potato (Solanum tuberosum L.) tuber, electrical impedance, membrane capacitance, heat injury, membrane thermostability.
Effect of light on hormonal regulation of sexual reproduction in Phytophthora parasitica
Authors: Chern L. L. , Ko W. H.
Published: April 2008

A1 and A2 isolates of Phytophthora parasitica were exposed to light at different stages of sexual development to study the mode of action of light on sexual reproduction. Exposure to light during the process of sexual reproduction reduced the number of oospores produced to about 7% of that produced in darkness. Light was inhibitory to production of α hormones but not receptors of these hormones by both A1 and A2 isolates of P. parasitica. However, after being produced, α hormones were stable under light. The number of oospores produced was greatly reduced when A1 and A2 cultures were exposed to light during hormone induction of sexual reproduction but was not affected when the cultures were exposed to light during oospore formation after hormone induction. The results suggest that the effect of light on sexual reproduction in P. parasitica was mainly through inhibition of hormone production and hormone induction of sexual reproduction. Key words: Phytophthora parasitica, light effect, hormonal regulation.