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Aims: To determine whether paediatric congenital heart disease (CHD) patients with epicardial cardiac implantable electronic devices (CIEDs) receive high cumulative effective doses (CEDs) of ionizing radiation from medical imaging tests. Methods and results: We compared 28 paediatric CHD patients with epicardial CIEDs (cases) against 40 patients with no CIED matched by age at operation, sex, surgical era, and CHD diagnosis (controls). We performed a retrospective review of radiation exposure from medical imaging exams between 2006 and 2022. Radiation dose from computed tomography (CT) and X-ray radiography was calculated using the National Cancer Institute Radiation Dosimetry Tool. We performed univariate analysis to compare the CED between the two groups. In the case subgroup, we convened experts' review to adjudicate the prevalence of CT exams that should have been performed with magnetic resonance imaging (MRI) in the absence of a CIED. Children (median age 2.5 years at implant) with CIEDs received significantly higher median CED compared with matched controls (6.90 vs. 1.72 mSv, P = 0.0018). In cases, expert adjudication showed that 80% of the CT exams would have been performed with MRI in the absence of a CIED. This resulted, on average, a five-fold increase in the effective dose (ED) from post-lead implant CTs. Conclusion: Paediatric CHD patients with CIED received four times higher CED than matched controls. Improved access to medical imaging tests without ionizing radiation, such as MRI, could potentially reduce the ED in CIED patients by up to five times.
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As part of a study to investigate the use of the scuticociliate Orchitophrya stellarum as a biological control for the invasive seastar Asterias amurensis in Australia, we collected prevalence data for O. stellarum from 3 seastar species (A. amurensis, A. rubens, Pisaster ochraceus) between 1996 and 1999 from the Pacific (Australia, Japan, Korea, Canada) and Atlantic (France, Netherlands, Canada) oceans. In the Pacific Ocean, for the first time, we found O. stellarum in male A. amurensis in Korea and female A. amurensis in Japan. The parasite was not detected in the invasive A. amurensis from Australia. There was no significant difference between size of infected and uninfected male seastars, nor a correlation between biased sex ratio and parasite prevalence in populations in the Pacific or Atlantic oceans. Therefore, unlike other studies, we found size and sex ratio in seastar populations in the field are unreliable indicators of parasite impacts. Regular monitoring of infected seastar populations in the field would be useful to better understand how sex ratio varies with parasite prevalence. We recommend laboratory studies under controlled conditions to determine the effect of O. stellarum on seastar populations.
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Oligohimenóforos , Estrellas de Mar , Masculino , Femenino , Animales , Estrellas de Mar/parasitología , Prevalencia , Océanos y Mares , Océano Atlántico , Océano PacíficoRESUMEN
Reject rate analysis is considered an integral part of a diagnostic radiography quality control (QC) program. A rejected image is a patient radiograph that was not presented to a radiologist for diagnosis and that contributes unnecessary radiation dose to the patient. Reject rates that are either too high or too low may suggest systemic department shortcomings in QC mechanisms. Due to the lack of standardization, reject data often cannot be easily compared between radiography systems from different vendors. The purpose of this report is to provide guidance to help standardize data elements that are required for comprehensive reject analysis and to propose data reporting and workflows to enable an effective and comprehensive reject rate monitoring program. Essential data elements, a proposed schema for classifying reject reasons, and workflow implementation options are recommended in this task group report.
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Radiografía , Humanos , Control de Calidad , Estándares de ReferenciaRESUMEN
There is limited research examining the inclusion of autistic people in their local communities. This paper reports on two Australian studies which explored this gap, focusing on both autistic people's experiences and non-autistic people's attitudes towards autistic individuals. Study One was conducted with primarily non-autistic people (n = 2,383), and Study Two with primarily parents and carers of autistic people (n = 1,297 people). The majority of non-autistic adults perceived discrimination against autistic people in the community; consistent with the experiences of autistic people and their carers. Of particular concern was more negative attitudes towards, and experiences of, autistic adults. There is an urgent need to improve society's acceptance and inclusion of autistic people of all ages.
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Trastorno del Espectro Autista , Trastorno Autístico , Adulto , Actitud , Australia , Humanos , PadresRESUMEN
This paper presents two studies that explored community attitudes to autism in Australia; and autistic people and their families' perspectives of community attitudes. In Study One 2424 (primarily non-autistic) people completed a survey on autism-related knowledge and attitudes; identifying a number of misperceptions and knowledge gaps in the general community. In Study Two 1353 people (primarily parents and carers of autistic people) completed a survey on autism-related experiences; identifying that the community's awareness of autism does not appear to extend to understanding how to support autistic people. There is a need for more research which integrates the perspectives of both autistic people and the broader community; and the development of communication and education interventions, with rather than about autistic people.
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Trastorno del Espectro Autista , Trastorno Autístico , Actitud , Trastorno Autístico/epidemiología , Humanos , Padres , Encuestas y CuestionariosRESUMEN
An orphaned black bear (Ursus americanus) cub, estimated to be 9 months-of-age was presented to a wildlife rehabilitation facility in December of 2016. The cub was afebrile, under-weight (6.8 kg) and had a cough condition. Centrifugal sugar fecal flotation examination failed to detect any gastrointestinal helminth or protozoan parasites, but revealed the presence of first-stage nematode larvae (L1). Large numbers of L1 (>8000 L1/g) identified as Crenosoma sp. based on morphology were recovered using the Baermann technique. Three species (Crenosoma petrowi, Crenosoma potos, Crenosoma vulpis) have been reported from black bears. Based on larval length measurements (range = 253-277 µm; mean = 263 µm; n = 8), the L1 were tentatively identified as C. petrowi. Further molecular characterization using Polymerase Chain Reaction (PCR) and DNA sequencing of the small subunit (SSU) RNA gene and two regions of the large subunit (LSU) rRNA gene did not match any submissions in GenBank, but were most similar to Crenosoma mephiditis. There is a paucity of molecular data for members of the genus Crenosoma, with only information for Crenosoma vulpis (red fox), C. mephitidis (skunks), Crenosoma striatum (hedgehog) and Crenosoma sp. (red panda) in GenBank. Molecular analysis eliminates C. vulpis as a possibility in this case but due to the lack of submissions in GenBank, the identification of the L1 as C. petrowi based on length measurements could not be confirmed. Receiving in total, three separate courses of treatment with fenbendazole (50 mg/kg, oral, once a day for 3 days), fecal larval shedding ceased and clinical signs resolved. The black bear cub was released into the wild in June 2017. This is the first report of clinical chronic respiratory disease due to Crenosoma sp. infection in a black bear.
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Antinematodos/uso terapéutico , Fenbendazol/uso terapéutico , Enfermedades Pulmonares Parasitarias/veterinaria , Metastrongyloidea/aislamiento & purificación , Infecciones por Strongylida/veterinaria , Ursidae , Animales , Femenino , Enfermedades Pulmonares Parasitarias/diagnóstico , Enfermedades Pulmonares Parasitarias/tratamiento farmacológico , Enfermedades Pulmonares Parasitarias/parasitología , Metastrongyloidea/clasificación , Nuevo Brunswick , Infecciones por Strongylida/diagnóstico , Infecciones por Strongylida/tratamiento farmacológico , Infecciones por Strongylida/parasitologíaRESUMEN
BACKGROUND: Diabetes is a major health concern in the U.S. with increasing prevalence. There are limited data on nurse practitioner (NP) roles in diabetes management and clinical patient outcomes in relation to national standards of care. This project aimed to identify rates of American Diabetes Association (ADA) guideline adherence of two NP-owned and operated practices during an ongoing four-year quality improvement project. METHODS: Methods: Electronic health records of 83 - 112 patients (depending on the year) ages > 18 years with type 2 diabetes were reviewed. Mean A1C and rates of adherence to ADA standards were compared from 2013 to 2017 and to national and state data. CONCLUSIONS: Findings demonstrated that diabetes management provided by NPs consistently adhered to national ADA standards of care and met or exceeded national data. This four-year ongoing quality improvement project has led to the implementation of practice modifications that continue to improve patient outcomes through increased adherence to ADA guidelines. IMPLICATIONS FOR PRACTICE: Strategies which improve adherence to ADA standards of care by NPs are essential. Identifying rates of adherence and implementing quality improvement strategies can significantly improve the quality of care provided to patients with diabetes.
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Diabetes Mellitus Tipo 2/terapia , Enfermeras Practicantes/normas , Indicadores de Calidad de la Atención de Salud/estadística & datos numéricos , Calidad de la Atención de Salud/normas , Adolescente , Adulto , Anciano , Femenino , Hemoglobina Glucada/análisis , Adhesión a Directriz/normas , Adhesión a Directriz/estadística & datos numéricos , Humanos , Masculino , Persona de Mediana Edad , Enfermeras Practicantes/estadística & datos numéricos , Pautas de la Práctica en Enfermería/organización & administración , Pautas de la Práctica en Enfermería/normas , Pautas de la Práctica en Enfermería/estadística & datos numéricos , Calidad de la Atención de Salud/estadística & datos numéricosRESUMEN
Following the largest Ebola virus disease outbreak from 2013 to 2016, viral RNA has been detected in survivors from semen and breast milk long after disease recovery. However, as there have been few cases of sexual transmission, it is unclear whether every RNA positive fluid sample contains infectious virus. Virus isolation, typically using cell culture or animal models, can serve as a tool to determine the infectivity of patient samples. However, the sensitivity of these methods has not been assessed for the Ebola virus isolate, Makona. Described here is an efficiency comparison of Ebola virus Makona isolation using Vero E6, Huh-7, monocyte-derived macrophage cells, and suckling laboratory mice. Isolation sensitivity was similar in all methods tested. Laboratory mice and Huh-7 cells were less affected by toxicity from breast milk than Vero E6 and MDM cells. However, the advantages associated with isolation in Huh-7 cells over laboratory mice, including cost effectiveness, sample volume preservation, and a reduction in animal use, make Huh-7 cells the preferred substrate tested for Ebola virus Makona isolation.
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Ebolavirus/aislamiento & purificación , Virología/métodos , Animales , Animales Lactantes , Línea Celular , Línea Celular Tumoral , Chlorocebus aethiops , Fiebre Hemorrágica Ebola/virología , Humanos , Macrófagos/virología , Ratones , Ratones Endogámicos BALB C , Leche Humana/virología , Semen/virología , Sensibilidad y Especificidad , Células VeroRESUMEN
BACKGROUND: Currently, no FDA-approved vaccines or treatments are available for Ebola virus disease (EVD), and therapy remains largely supportive. Ebola virus (EBOV) has broad tissue tropism and can infect a variety of cells including epithelial cells. Epithelial cells differ from most other cell types by their polarized phenotype and barrier function. In polarized cells, the apical and basolateral membrane domains are demarcated by tight junctions, and specialized sorting machinery, which results in a difference in composition between the two membrane domains. These specialized sorting functions can have important consequences for viral infections. Differential localization of a viral receptor can restrict virus entry to a particular membrane while polarized sorting can lead to a vectorial virus release. The present study investigated the impact of cell polarity on EBOV infection. METHODS: Characteristics of EBOV infection in polarized cells were evaluated in the polarized Caco-2 model grown on semipermeable transwells. Transepithelial resistance (TEER), which is a function of tight junctions, was used to assess epithelial cell polarization. EBOV infection was assessed with immunofluorescence microscopy and qPCR. Statistical significance was calculated using one-way ANOVA and significance was set at p < 0.05. RESULTS: Our data indicate that EBOV preferentially infects cells from the basolateral route, and this preference may be influenced by the resistance across the Caco-2 monolayer. Infection occurs without changes in cellular permeability. Further, our data show that basolateral infection bias may be dependent on polarized distribution of heparan sulfate, a known viral attachment factor. Treatment with iota-carrageenan, or heparin lyase, which interrupts viral interaction with cellular heparan sulfate, significantly reduced cell susceptibility to basolateral infection, likely by inhibiting virus attachment. CONCLUSIONS: Our results show cell polarity has an impact on EBOV infection. EBOV preferentially infects polarized cells through the basolateral route. Access to heparan sulfate is an important factor during basolateral infection and blocking interaction of cellular heparan sulfate with virus leads to significant inhibition of basolateral infection in the polarized Caco-2 cell model.
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Ebolavirus/fisiología , Células Epiteliales/virología , Heparitina Sulfato/metabolismo , Acoplamiento Viral , Células CACO-2 , Humanos , Microscopía Fluorescente , Reacción en Cadena en Tiempo Real de la PolimerasaRESUMEN
Oligodendrocyte progenitor cells (OPC) undergo asymmetric cell division (ACD) to generate one OPC and one differentiating oligodendrocyte (OL) progeny. Loss of pro-mitotic proteoglycan and OPC marker NG2 in the OL progeny is the earliest immunophenotypic change of unknown mechanism that indicates differentiation commitment. Here, we report that expression of the mouse homolog of Drosophila tumor suppressor Lethal giant larvae 1 (Lgl1) is induced during OL differentiation. Lgl1 conditional knockout OPC progeny retain NG2 and show reduced OL differentiation, while undergoing more symmetric self-renewing divisions at the expense of asymmetric divisions. Moreover, Lgl1 and hemizygous Ink4a/Arf knockouts in OPC synergistically induce gliomagenesis. Time lapse and total internal reflection microscopy reveals a critical role for Lgl1 in NG2 endocytic routing and links aberrant NG2 recycling to failed differentiation. These data establish Lgl1 as a suppressor of gliomagenesis and positive regulator of asymmetric division and differentiation in the healthy and demyelinated murine brain.
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Glicoproteínas/metabolismo , Oligodendroglía/citología , Oligodendroglía/metabolismo , Proteoglicanos/metabolismo , Animales , División Celular Asimétrica/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Células Cultivadas , Técnica del Anticuerpo Fluorescente , Glicoproteínas/genética , Immunoblotting , Ratones , Monensina/farmacología , Oligodendroglía/efectos de los fármacos , Transducción de Señal/efectos de los fármacosRESUMEN
AIM: The aim of the present study was to develop a parent-reported tool that will measure health-related quality of life (HRQoL) in children following ketogenic diet (KD) therapies for refractory epilepsy once it has been pilot tested and analysed. METHODS: Parents of children following KD therapies for epilepsy were recruited through a public hospital in Queensland, Australia, in 2012 and 2014. Qualitative semistructured interviews were conducted in 2012 with 13 parents who described changes seen in their child's HRQoL while on the KD. A quality of life tool (QoL) was developed by adapting the Quality of Life in Childhood Epilepsy tool based on results and themes analysed from the interviews. The KetoQoL was pilot tested with 18 parents recruited in 2014. Interrelationships between variables and questions were explored with exploratory factor analysis (EFA) to determine which questions had the greatest effect on QoL. RESULTS: The first iteration of the KetoQoL consisted of five main domains: physical, cognitive, social, intrapersonal and effects on the family. The domains were subdivided into 18 variables, totalling 54 items. EFA demonstrated that items from the physical and effects on the family domains had the greatest effect on QoL. CONCLUSIONS: KetoQoL is an HRQoL tool developed using a range of methods and assessed for both face and content validity. Further testing of KetoQoL is required to refine and confirm the factors. This work will enhance the evaluation of treatment effectiveness in children with epilepsy following the KD.
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Dieta Cetogénica/psicología , Epilepsia Refractaria/dietoterapia , Epilepsia Refractaria/psicología , Padres , Calidad de Vida , Encuestas y Cuestionarios , Adulto , Cuidadores , Niño , Conducta Infantil , Cognición , Relaciones Familiares , Femenino , Humanos , Relaciones Interpersonales , Masculino , Proyectos Piloto , Reproducibilidad de los Resultados , Convulsiones/dietoterapia , Conducta SocialRESUMEN
A dog from western Newfoundland was presented with paradoxical vestibular syndrome. First-stage larvae of Angiostrongylus vasorum were detected on fecal examination. Treatment with milbemycin oxime resulted in resolution of signs. This is the first report of the spread of this parasite to western Newfoundland and of paradoxical vestibular syndrome in a dog infected with A. vasorum.
Syndrome vestibulaire paradoxal chez un chien de l'ouest de Terre-Neuve infecté par des vers du cÅur(Angiostrongylus vasorum). Un chien de l'ouest de Terre-Neuve a été présenté avec un syndrome vestibulaire paradoxal. Des larves de premier stade d'Angiostrongylus vasorum ont été détectées à l'examen fécal. Le traitement à l'aide d'oxime de milbémycine a produit une disparition des symptômes. Il s'agit du premier rapport de la propagation de ce parasite dans l'ouest de Terre-Neuve et du syndrome vestibulaire paradoxal chez un chien infecté par A. vasorum.(Traduit par Isabelle Vallières).
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Angiostrongylus/aislamiento & purificación , Enfermedades de los Perros/parasitología , Infecciones por Strongylida/veterinaria , Enfermedades Vestibulares/veterinaria , Aminas/administración & dosificación , Aminas/uso terapéutico , Analgésicos/administración & dosificación , Analgésicos/uso terapéutico , Animales , Antihelmínticos/administración & dosificación , Antihelmínticos/uso terapéutico , Ácidos Ciclohexanocarboxílicos/administración & dosificación , Ácidos Ciclohexanocarboxílicos/uso terapéutico , Dexametasona/administración & dosificación , Dexametasona/uso terapéutico , Difenhidramina/administración & dosificación , Difenhidramina/uso terapéutico , Enfermedades de los Perros/epidemiología , Perros , Gabapentina , Antagonistas de los Receptores Histamínicos/administración & dosificación , Antagonistas de los Receptores Histamínicos/uso terapéutico , Inmunosupresores/administración & dosificación , Inmunosupresores/uso terapéutico , Macrólidos/administración & dosificación , Macrólidos/uso terapéutico , Masculino , Terranova y Labrador/epidemiología , Infecciones por Strongylida/tratamiento farmacológico , Infecciones por Strongylida/epidemiología , Infecciones por Strongylida/parasitología , Enfermedades Vestibulares/tratamiento farmacológico , Enfermedades Vestibulares/etiología , Ácido gamma-Aminobutírico/administración & dosificación , Ácido gamma-Aminobutírico/uso terapéuticoRESUMEN
Inhibitors of BRAFV600E kinase are currently under investigations in preclinical and clinical studies involving BRAFV600E glioma. Studies demonstrated clinical response to such individualized therapy in the majority of patients whereas in some patients tumors continue to grow despite treatment. To study resistance mechanisms, which include feedback activation of mitogen-activated protein kinase (MAPK) signaling in melanoma, we developed a luciferase-modified cell line (2341luc) from a BrafV600E mutant and Cdkn2a- deficient murine high-grade glioma, and analyzed its molecular responses to BRAFV600E- and MAPK kinase (MEK)-targeted inhibition. Immunocompetent, syngeneic FVB/N mice with intracranial grafts of 2341luc were tested for effects of BRAFV600E and MEK inhibitor treatments, with bioluminescence imaging up to 14-days after start of treatment and survival analysis as primary indicators of inhibitor activity. Intracranial injected tumor cells consistently generated high-grade glioma-like tumors in syngeneic mice. Intraperitoneal daily delivery of BRAFV600E inhibitor dabrafenib only transiently suppressed MAPK signaling, and rather increased Akt signaling and failed to extend survival for mice with intracranial 2341luc tumor. MEK inhibitor trametinib delivered by oral gavage daily suppressed MAPK pathway more effectively and had a more durable anti-growth effect than dabrafenib as well as a significant survival benefit. Compared with either agent alone, combined BRAFV600E and MEK inhibitor treatment was more effective in reducing tumor growth and extending animal subject survival, as corresponding to sustained MAPK pathway inhibition. Results derived from the 2341luc engraftment model application have clinical implications for the management of BRAFV600E glioma.
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Antineoplásicos/farmacología , Glioma/genética , Glioma/metabolismo , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Proteínas Proto-Oncogénicas B-raf/genética , Animales , Apoptosis/efectos de los fármacos , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Codón , Modelos Animales de Enfermedad , Activación Enzimática/efectos de los fármacos , Expresión Génica , Técnicas de Inactivación de Genes , Genotipo , Glioma/tratamiento farmacológico , Glioma/patología , Humanos , Ratones , Terapia Molecular Dirigida , Mutación , Clasificación del Tumor , Trasplante IsogénicoRESUMEN
Rotational harvesting is one of the oldest management strategies applied to terrestrial and marine natural resources, with crop rotations dating back to the time of the Roman Empire. The efficacy of this strategy for sessile marine species is of considerable interest given that these resources are vital to underpin food security and maintain the social and economic wellbeing of small-scale and commercial fishers globally. We modeled the rotational zone strategy applied to the multispecies sea cucumber fishery in Australia's Great Barrier Reef Marine Park and show a substantial reduction in the risk of localized depletion, higher long-term yields, and improved economic performance. We evaluated the performance of rotation cycles of different length and show an improvement in biological and economic performance with increasing time between harvests up to 6 y. As sea cucumber fisheries throughout the world succumb to overexploitation driven by rising demand, there has been an increasing demand for robust assessments of fishery sustainability and a need to address local depletion concerns. Our results provide motivation for increased use of relatively low-information, low-cost, comanagement rotational harvest approaches in coastal and reef systems globally.
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Acuicultura/métodos , Conservación de los Recursos Naturales/métodos , Explotaciones Pesqueras , Pepinos de Mar , Animales , Acuicultura/economía , Biomasa , Técnicas de Apoyo para la Decisión , Explotaciones Pesqueras/economía , Modelos Teóricos , Océano Pacífico , Queensland , Conducta de Reducción del RiesgoRESUMEN
Diffusion MRI has become an invaluable tool for studying white matter microstructure and brain connectivity. The emergence of quantitative susceptibility mapping and susceptibility tensor imaging (STI) has provided another unique tool for assessing the structure of white matter. In the highly ordered white matter structure, diffusion MRI measures hindered water mobility induced by various tissue and cell membranes, while susceptibility sensitizes to the molecular composition and axonal arrangement. Integrating these two methods may produce new insights into the complex physiology of white matter. In this study, we investigated the relationship between diffusion and magnetic susceptibility in the white matter. Experiments were conducted on phantoms and human brains in vivo. Diffusion properties were quantified with the diffusion tensor model and also with the higher order tensor model based on the cumulant expansion. Frequency shift and susceptibility tensor were measured with quantitative susceptibility mapping and susceptibility tensor imaging. These diffusion and susceptibility quantities were compared and correlated in regions of single fiber bundles and regions of multiple fiber orientations. Relationships were established with similarities and differences identified. It is believed that diffusion MRI and susceptibility MRI provide complementary information of the microstructure of white matter. Together, they allow a more complete assessment of healthy and diseased brains.
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PURPOSE: This study determined injury incidence and examined the association between musculoskeletal injuries and potential intrinsic and extrinsic risk factors. METHODS: This retrospective cohort study involved a survey of 593 volunteers from two battalions of a Stryker Brigade Combat Team upon completion of a 12-mo deployment to Afghanistan. The survey included questions on physical characteristics, work duties, equipment worn, fitness training, and injuries experienced during the deployment. RESULTS: Of the surveyed soldiers, 45% sustained an injury during the deployment. Total injuries resulted in 5049 d of limited duty, an average of 8.5 d per injury. The body regions with the largest numbers of injuries were the low back (17.4%), knee (12.7%), and shoulder (10.0%). The majority (65%) of injuries occurred while working. The most frequent activities soldiers reported as the cause of injury were lifting and carrying (9.8%), dismounted patrolling (9.6%), and physical training (8.0%). Older age, higher enlisted rank, female sex, months deployed, more time spent standing, longer strength training sessions, heaviest load worn, and heavier or more frequent lifting tasks were all associated with injury. DISCUSSION: Tasks requiring physical energy expenditure such as load carriage, lifting, or standing resulted in an increased risk of musculoskeletal injury in this study. Lifting/carrying, dismounted patrols, and physical training were associated with 26% of musculoskeletal injuries. The weight of loads carried and lifting may be exceeding the work capacity of the soldiers, resulting in injury. These injuries in turn limit available work days for military units, reducing combat power.
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Contusiones/epidemiología , Personal Militar , Síndromes de Compresión Nerviosa/epidemiología , Traumatismos Ocupacionales/epidemiología , Esguinces y Distensiones/epidemiología , Adulto , Campaña Afgana 2001- , Factores de Edad , Estudios de Cohortes , Femenino , Humanos , Articulaciones/lesiones , Elevación , Masculino , Músculo Esquelético/lesiones , Postura , Entrenamiento de Fuerza , Estudios Retrospectivos , Factores de Riesgo , Factores Sexuales , Factores de Tiempo , Estados Unidos/epidemiología , Soporte de PesoRESUMEN
The encounter/compatibility paradigm of host specificity provides three qualitative pathways to the success or failure of a potential host-parasite interaction. It is usually impossible to distinguish between two of these (encounter and compatibility filters closed versus encounter filter open and compatibility filter closed) because unsuccessful infection attempts are difficult to observe in nature. We were able to open the encounter filter under experimental laboratory conditions. Our analytical system used the rhizocephalan barnacle, Sacculina carcini, a parasitic castrator of the European green crab, Carcinus maenas, and Pachygrapsus marmoratus, a native European crab that occurs with C. maenas but is not parasitized by S. carcini in nature. Penetration followed by unsuccessful infection of P. marmoratus crabs by parasitic barnacle larvae leaves a uniquely permanent record in the thoracic ganglion of the crabs. This provided us with a novel tool to quantify the encounter filter in a host-parasite system in nature. We demonstrated, in the laboratory, that the compatibility filter was closed and that, in nature, even where barnacle larvae were present, the encounter filter was also effectively closed. The closure of both filters in nature explains the failure of this potential host-parasite interaction, an outcome favored by selection in both host and parasite.
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Braquiuros/parasitología , Thoracica/fisiología , Animales , Femenino , Ganglios/parasitología , Interacciones Huésped-Parásitos/fisiología , Larva/fisiología , MasculinoRESUMEN
The invasive green alga Caulerpa taxifolia has gained a high profile due to 'outbreaks' in the Mediterranean and California. During the year 2000 three new discrete locations colonised by abundant C. taxifolia were discovered in New South Wales (NSW), Australia. Sequencing of the internal transcribed spacer (ITS) region of the ribosomal DNA was used to explore the source(s) of these new records, which is an important prerequisite for subsequent environmental management responses. Our results indicate that the NSW C. taxifolia originated from several sources and, hence, through different invasion events. For two of the new records (Port Hacking, Careel Bay) it can be excluded that they are derived from the so-called "aquarium strain" of C. taxifolia, closely related to the invasive Mediterranean populations. Port Hacking is likely to have originated from tropical native populations. However, samples from Lake Conjola cannot be sufficiently distinguished with the applied technique from native C. taxifolia in Moreton Bay and the Mediterranean/"aquarium strain".