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1.
Nature ; 563(7731): 365-368, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-30429552

RESUMEN

Barnard's star is a red dwarf, and has the largest proper motion (apparent motion across the sky) of all known stars. At a distance of 1.8 parsecs1, it is the closest single star to the Sun; only the three stars in the α Centauri system are closer. Barnard's star is also among the least magnetically active red dwarfs known2,3 and has an estimated age older than the Solar System. Its properties make it a prime target for planetary searches; various techniques with different sensitivity limits have been used previously, including radial-velocity imaging4-6, astrometry7,8 and direct imaging9, but all ultimately led to negative or null results. Here we combine numerous measurements from high-precision radial-velocity instruments, revealing the presence of a low-amplitude periodic signal with a period of 233 days. Independent photometric and spectroscopic monitoring, as well as an analysis of instrumental systematic effects, suggest that this signal is best explained as arising from a planetary companion. The candidate planet around Barnard's star is a cold super-Earth, with a minimum mass of 3.2 times that of Earth, orbiting near its snow line (the minimum distance from the star at which volatile compounds could condense). The combination of all radial-velocity datasets spanning 20 years of measurements additionally reveals a long-term modulation that could arise from a stellar magnetic-activity cycle or from a more distant planetary object. Because of its proximity to the Sun, the candidate planet has a maximum angular separation of 220 milliarcseconds from Barnard's star, making it an excellent target for direct imaging and astrometric observations in the future.

2.
Med Vet Entomol ; 37(2): 195-208, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36695750

RESUMEN

There is an urgent need for continued research on the ecology of tick-borne diseases in Africa. Our objective was to provide a preliminary description of the ecology and epidemiology of tick species, tick-borne pathogens, and animal hosts in Zimbabwe, focusing efforts at Victoria Falls National Park, for a single season. We tested the hypothesis that tick surveillance and pathogen screening data can be used to model associations among ticks, hosts, and pathogens. We collected ticks from domesticated animals and wildlife in Zimbabwe and screened the ticks for the presence of Anaplasma and Ehrlichia bacteria. Nearly 30% of the screened ticks were PCR-positive; 89% of tick species were PCR-positive, and 88% of animal species carried at least one PCR-positive tick. We sequenced a subset of amplicons that were similar to three Anaplasma species and three Ehrlichia species. The odds of a tick being PCR-positive increased when many ticks were collected from the host or the tick was collected from a cow (domesticated animal). Tick species shared host species more often than expected. We demonstrate that ticks in northwestern Zimbabwe present a One Health problem for nearby wildlife and humans.


Asunto(s)
Rickettsia , Enfermedades por Picaduras de Garrapatas , Garrapatas , Bovinos , Femenino , Animales , Humanos , Anaplasma , Zimbabwe/epidemiología , Parques Recreativos , Estaciones del Año , Ehrlichia , Animales Salvajes , Enfermedades por Picaduras de Garrapatas/microbiología , Enfermedades por Picaduras de Garrapatas/veterinaria
3.
Nature ; 536(7617): 437-40, 2016 08 25.
Artículo en Inglés | MEDLINE | ID: mdl-27558064

RESUMEN

At a distance of 1.295 parsecs, the red dwarf Proxima Centauri (α Centauri C, GL 551, HIP 70890 or simply Proxima) is the Sun's closest stellar neighbour and one of the best-studied low-mass stars. It has an effective temperature of only around 3,050 kelvin, a luminosity of 0.15 per cent of that of the Sun, a measured radius of 14 per cent of the radius of the Sun and a mass of about 12 per cent of the mass of the Sun. Although Proxima is considered a moderately active star, its rotation period is about 83 days (ref. 3) and its quiescent activity levels and X-ray luminosity are comparable to those of the Sun. Here we report observations that reveal the presence of a small planet with a minimum mass of about 1.3 Earth masses orbiting Proxima with a period of approximately 11.2 days at a semi-major-axis distance of around 0.05 astronomical units. Its equilibrium temperature is within the range where water could be liquid on its surface.


Asunto(s)
Planetas , Estrellas Celestiales , Medio Ambiente Extraterrestre/química , Rotación , Temperatura , Agua/análisis , Agua/química
4.
J Appl Microbiol ; 130(2): 464-477, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32687650

RESUMEN

AIMS: To understand the genetics involved in surface attachment and biofilm formation of Listeria monocytogenes. METHODS AND RESULTS: An in vitro screen of a Himar1 transposon library of L. monocytogenes strain 15G01 identified three transposants that produced significantly different biofilm levels when compared to the wild-type strain; two mutants exhibited enhanced biofilm formation and one produced less biofilm biomass than the wild-type. The mutant 15G01 mprF::Himar1, which had a transposon insertion in the mprF gene, was selected for further analysis. The mutant produced a more densely populated biofilm on solid surfaces such as stainless steel and polystyrene, as determined using scanning electron and light microscopy. The 15G01 mprF::Himar1 mutant remained viable in biofilms, but showed an increase in sensitivity to the cationic antimicrobial gallidermin. The mutant also displayed reduced invasiveness in CaCo-2 intestinal cells, suggesting virulence properties are compromised by the inactivation of mprF. CONCLUSIONS: Biofilm formation and gallidermin resistance of L. monocytogenes is influenced by mprF, but this trait is associated with a compromise in invasiveness. SIGNIFICANCE AND IMPACT OF THE STUDY: The presence of pathogenic microorganisms in the food processing environment can cause a significant problem, especially when these microorganisms are established as biofilms. This study shows that the inactivation of the mprF gene results in enhanced biofilm formation and abiotic surface attachment of L. monocytogenes.


Asunto(s)
Péptidos Catiónicos Antimicrobianos/farmacología , Proteínas Bacterianas/metabolismo , Biopelículas/crecimiento & desarrollo , Farmacorresistencia Bacteriana/genética , Listeria monocytogenes/fisiología , Proteínas Bacterianas/genética , Células CACO-2 , Humanos , Listeria monocytogenes/efectos de los fármacos , Listeria monocytogenes/genética , Listeria monocytogenes/patogenicidad , Mutación , Virulencia/genética
5.
Nature ; 523(7562): 568-71, 2015 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-26223623

RESUMEN

Aurorae are detected from all the magnetized planets in our Solar System, including Earth. They are powered by magnetospheric current systems that lead to the precipitation of energetic electrons into the high-latitude regions of the upper atmosphere. In the case of the gas-giant planets, these aurorae include highly polarized radio emission at kilohertz and megahertz frequencies produced by the precipitating electrons, as well as continuum and line emission in the infrared, optical, ultraviolet and X-ray parts of the spectrum, associated with the collisional excitation and heating of the hydrogen-dominated atmosphere. Here we report simultaneous radio and optical spectroscopic observations of an object at the end of the stellar main sequence, located right at the boundary between stars and brown dwarfs, from which we have detected radio and optical auroral emissions both powered by magnetospheric currents. Whereas the magnetic activity of stars like our Sun is powered by processes that occur in their lower atmospheres, these aurorae are powered by processes originating much further out in the magnetosphere of the dwarf star that couple energy into the lower atmosphere. The dissipated power is at least four orders of magnitude larger than what is produced in the Jovian magnetosphere, revealing aurorae to be a potentially ubiquitous signature of large-scale magnetospheres that can scale to luminosities far greater than those observed in our Solar System. These magnetospheric current systems may also play a part in powering some of the weather phenomena reported on brown dwarfs.

6.
Neuroimage ; 206: 116323, 2020 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-31678228

RESUMEN

Recent work in early visual cortex of humans has shown that the BOLD signal exhibits contrast dependent orientation tuning, with an inverse oblique effect (oblique > cardinal) at high contrast and a horizontal effect (vertical > horizontal) at low contrast. This finding is at odds with decades of neurophysiological research demonstrating contrast invariant orientation tuning in primate visual cortex, yet the source of this discrepancy is unclear. We hypothesized that contrast dependent BOLD orientation tuning may arise due to contrast dependent influences of feedforward (FF) and feedback (FB) synaptic activity, indexed through gamma and alpha rhythms, respectively. To quantify this, we acquired EEG and BOLD in healthy humans to generate and compare orientation tuning curves across all neural frequency bands with BOLD. As expected, BOLD orientation selectivity in V1 was contrast dependent, preferring oblique orientations at high contrast and vertical at low contrast. On the other hand, EEG orientation tuning was contrast invariant, though frequency-specific, with an inverse-oblique effect in the gamma band (FF) and a horizontal effect in the alpha band (FB). Therefore, high-contrast BOLD orientation tuning closely matched FF activity, while at low contrast, BOLD best resembled FB orientation tuning. These results suggest that contrast dependent BOLD orientation tuning arises due to the reduced contribution of FF input to overall neurophysiological activity at low contrast, shifting BOLD orientation tuning towards the orientation preferences of FB at low contrast.


Asunto(s)
Sensibilidad de Contraste , Orientación Espacial/fisiología , Corteza Visual/diagnóstico por imagen , Percepción Visual/fisiología , Adulto , Ritmo alfa , Electroencefalografía , Retroalimentación , Femenino , Neuroimagen Funcional , Ritmo Gamma , Humanos , Imagen por Resonancia Magnética , Masculino , Oxígeno , Corteza Visual/fisiología , Vías Visuales/diagnóstico por imagen , Vías Visuales/fisiología , Adulto Joven
7.
BMC Cancer ; 20(1): 1125, 2020 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-33218337

RESUMEN

An amendment to this paper has been published and can be accessed via the original article.

8.
BMC Cancer ; 20(1): 899, 2020 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-32962660

RESUMEN

BACKGROUND: Art therapy may improve the physical, mental, and emotional wellbeing of individuals for a variety of purposes. It remains understudied and underutilized in cancer care. We sought to determine the ability of a pilot art therapy program to improve the physical, mental, and emotional well-being of cancer patients. METHODS: Chemotherapy-recipients, age 18 years and older, diagnosed with any type or stage of cancer, were considered eligible to participate in this single arm, pilot study, using four visual analog scales (VAS) with visually-similar, 0-10 scale (10 being worst) thermometers assessing: 1) pain, 2) emotional distress, 3) depression, and 4) anxiety. Participants were asked to complete all 4 metrics, pre-treatment, post-treatment, and at 48-72 h follow-up, after an hour-long art therapy session. Primary endpoints included post-intervention changes from baseline in the 4 VAS metrics. RESULTS: Through a reasonable pilot sample (n = 50), 44% had breast cancer, 22% gastrointestinal cancers, 18% hematological malignancies, and 20% had other malignancies. A decrease in all VAS measures was noted immediately post-treatment but remained low only for pain and depression, not for emotional distress and anxiety upon follow up. There was a significant difference between the depression VAS scores of Hispanics (32%) compared to non-Hispanics (56%) (p = 0.009) at baseline. However, compared to non-Hispanics, Hispanics exhibited higher levels of depression after art therapy (P = 0.03) and during the follow-up intervals (p = 0.047). CONCLUSION: Art therapy improved the emotional distress, depression, anxiety and pain among all cancer patients, at all time points. While depression scores were higher pre-intervention for Hispanic patients, Hispanic patients were noted to derive a greater improvement in depression scores from art therapy over time, compared to non-Hispanics patients. Discovering simple, effective, therapeutic interventions, to aid in distress relief in cancer patients, is important for ensuring clinical efficacy of treatment and improved quality of life.


Asunto(s)
Arteterapia/métodos , Neoplasias/psicología , Distrés Psicológico , Adolescente , Adulto , Anciano , Ansiedad/etiología , Ansiedad/psicología , Ansiedad/terapia , Dolor en Cáncer/terapia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neoplasias/tratamiento farmacológico , Proyectos Piloto , Estudios Prospectivos , Adulto Joven
9.
Public Health ; 171: 97-105, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31121558

RESUMEN

OBJECTIVES: National vaccination coverage in Sweden is high. Recurrent outbreaks of measles and rubella however highlight some immunity gaps in the population. Current knowledge about immunization status of undocumented migrant children is scant. The World Health Organization/Europe has developed the Guide to Tailoring Immunization Programmes (TIP) to assist countries in diagnosing barriers and motivators to vaccination in communities with low vaccination coverage. Based on the TIP guide, the objective of this study was to explore determinants to vaccination among undocumented immigrants, using qualitative approach. STUDY DESIGN: The study consisted of three steps: (i) an initial workshop for problem statement; (ii) qualitative research for increased understanding of the vaccination practices of children in the undocumented community; and (iii) a second workshop to incorporate the qualitative interview findings together with data from key stakeholders into a conceptual framework. METHODS: This was a qualitative study featuring interviews of seven undocumented parents recruited at non-governmental clinics, three nurses at Child Health Centers, and information from key stakeholders retrieved at workshops as part of the TIP process. RESULTS: The content analysis revealed two main themes: parental fear of being questioned and parental acceptance of child immunization. Undocumented parents had a positive view and attitude toward childhood immunization but expressed strong fear of being asked for identification papers at healthcare facilities. Owing to lack of knowledge on entitlements of the undocumented among health personnel, parents were incorrectly rejected when seeking care for their children. Frequent mobility among undocumented may limit access to complete the immunization schedule. Undocumented parents mistrust healthcare providers and avoid health facilities, further delaying childrens' access to health care, including immunization services. CONCLUSIONS: The findings of this study confirm the complexity of barriers that undocumented parents face regarding childhood immunization. The TIP guide offers a valuable process for a deeper understanding of the determinants of immunization challenges among undocumented migrants.


Asunto(s)
Padres/psicología , Inmigrantes Indocumentados/psicología , Inmigrantes Indocumentados/estadística & datos numéricos , Vacunación/estadística & datos numéricos , Niño , Miedo , Humanos , Programas de Inmunización/organización & administración , Guías de Práctica Clínica como Asunto , Investigación Cualitativa , Suecia , Organización Mundial de la Salud
10.
Occup Med (Lond) ; 68(3): 177-183, 2018 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-29788506

RESUMEN

Background: Most studies of the psychological impact of military deployment focus on the negative and traumatic aspects. Less is known about the full range of deployment experiences nor how these may impact on career intentions. Aims: To examine subjective operational experiences and career intentions in deployed UK military personnel using data gathered toward the end of an operational deployment. Methods: Data were gathered during deployment in Iraq and Afghanistan. A self-report survey collected data on sociodemographic, operational and military factors. Respondents provided their strength of agreement or disagreement with six potentially positive deployment experiences and their endorsement or rejection of six possible career intentions. Two mental health measures assessed symptoms of common mental disorder and post-traumatic stress disorder. Results: Responses were 681 in Iran 2009 (100% response rate); 1421 in Afghanistan in 2010 (100%), 1362 in 2011 (96%) and 860 in 2015 (91%). Five of the potentially positive outcomes were endorsed by >50% of the sample: confidence about remaining healthy after returning home, pride in accomplishments, increased confidence in abilities, improved unit cohesion and experiencing a positive life effect. Ninety per cent of respondents planned to continue in service after returning home. Fewer positive deployment experiences, poorer mental health, lesser unit cohesion and more negative impressions of leadership were significantly associated with intention to leave service. Conclusions: Contrary to the popular belief that UK military personnel deployed to Iraq or Afghanistan experience negative outcomes, this paper shows that deployment can be a positive experience for a substantial majority of deployed personnel.


Asunto(s)
Movilidad Laboral , Trastornos de Combate/complicaciones , Intención , Personal Militar/psicología , Adulto , Campaña Afgana 2001- , Trastornos de Combate/psicología , Femenino , Humanos , Guerra de Irak 2003-2011 , Acontecimientos que Cambian la Vida , Masculino , Personal Militar/estadística & datos numéricos , Factores de Riesgo , Autoinforme , Encuestas y Cuestionarios , Reino Unido , Guerra
11.
Clin Genet ; 89(3): 328-31, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25920394

RESUMEN

Population-based testing for BRCA1/2 mutations detects a high proportion of carriers not identified by cancer family history-based testing. We sought to determine whether population-based testing is an effective approach to genetic testing in the Bahamas, where 23% of women with breast cancer carry one of seven founder mutations in the BRCA1 or BRCA2 gene. We determined the prevalence of founder BRCA mutations in 1847 Bahamian women without a personal history of breast or ovarian cancer, unselected for age or family history. We found that 2.8% (20/705) of unaffected women with a family history of breast/ovarian cancer and 0.09% (1/1089) of unaffected women without a family history carry a BRCA mutation. A total of 38% of unaffected women with a known mutation in the family were found to carry the familial mutation. We previously suggested that all Bahamian women with breast or ovarian cancer be offered genetic testing. These current data suggest that additionally all unaffected Bahamian women with a family history of breast/ovarian cancer should be offered genetic testing for the founder BRCA mutations.


Asunto(s)
Proteína BRCA1/genética , Proteína BRCA2/genética , Efecto Fundador , Frecuencia de los Genes , Mutación , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Bahamas , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Femenino , Predisposición Genética a la Enfermedad , Pruebas Genéticas , Humanos , Persona de Mediana Edad , Neoplasias Ováricas/genética , Neoplasias Ováricas/metabolismo , Adulto Joven
12.
Haemophilia ; 22(1): e11-7, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26517156

RESUMEN

AIM: The National Hemophilia Program Coordinating Center, with the U.S. Regional Hemophilia Network conducted a national needs assessment of U.S. Hemophilia Treatment Center (HTC) patients. The objectives were to determine: (i) To what extent do patients report that they receive needed services and education; (ii) How well do the services provided meet their needs; and (iii) What are the patients' perspectives about their care. METHODS: A survey was mailed to active patients of 129 HTCs. Respondents completed the anonymous surveys on line or returned them by mail. Questions focused on management and information, access and barriers to care, coping, resources, and transition. RESULTS: Of 24 308 questionnaires mailed, 4004 (16.5%) were returned. Most respondents reported very few gaps in needed services or information and reported that services and information met their needs. Over 90% agreed or strongly agreed that care was patient-centred and rated HTC care as important or very important. Identified gaps included dietary advice, genetic testing, information on ageing, sexual health and basic needs resources. Minority respondents reported more barriers. CONCLUSION: This survey is the largest assessment of the HTC population. Respondents reported that the services and information provided by the HTCs met their needs. Quality improvement opportunities include transition and services related to ageing and sexual health. Further investigation of barriers to care for minorities is underway. Results will help develop national priorities to better serve all patients in the US. HTCs.


Asunto(s)
Hemofilia A/terapia , Evaluación de Necesidades , Atención al Paciente/economía , Encuestas y Cuestionarios , Adolescente , Adulto , Niño , Preescolar , Atención a la Salud , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Estados Unidos , Adulto Joven
13.
J Shoulder Elbow Surg ; 25(4): 614-8, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26652697

RESUMEN

BACKGROUND: Tranexamic acid (TXA) significantly decreases blood loss and transfusion rates after total hip and total knee arthroplasty. The purpose of this study was to determine the effects of intravenous TXA on blood loss and patient outcomes after total shoulder arthroplasty (TSA). METHODS: TXA was used in 106 consecutive patients undergoing primary anatomic and reverse TSA with a dose of 20 mg/kg intravenously (TXA group) and compared with the previous consecutive 88 patients without TXA (non-TXA group). All patients had a blood sample drawn for a hemoglobin and hematocrit determination the morning after surgery. Analysis of variance and χ(2) techniques were used to analyze study hypotheses. RESULTS: Statistically significant differences in both hemoglobin loss (TXA group Δ = 2.13 vs. non-TXA group Δ = 2.63; P = .01) and hematocrit loss (TXA group Δ = 6.4 vs. non-TXA group Δ = 8.14; P < .01) were seen in the TXA group compared with the non-TXA group. In patients receiving TXA, there were statistically significant decreases in the time spent in the recovery room (mean, TXA group 69 minutes vs. non-TXA group 87 minutes; P < .02) and total length of hospitalization (mean, TXA group 1.18 days vs. non-TXA group 1.4 days; P = .01). Two patients in the TXA group received a blood transfusion, whereas 6 patients in the non-TXA group did. CONCLUSIONS: TXA 20 mg/kg intravenously given just before primary anatomic and reverse TSA results in statistically significant reductions in blood loss. Patients spent 21% less time in the recovery room and had a 16% shorter hospitalization, resulting in financial savings for the hospital.


Asunto(s)
Antifibrinolíticos/uso terapéutico , Artroplastia de Reemplazo , Pérdida de Sangre Quirúrgica/prevención & control , Hemorragia Posoperatoria/prevención & control , Articulación del Hombro/cirugía , Ácido Tranexámico/uso terapéutico , Antifibrinolíticos/administración & dosificación , Transfusión Sanguínea , Femenino , Humanos , Infusiones Intravenosas , Tiempo de Internación , Masculino , Hemorragia Posoperatoria/etiología , Estudios Retrospectivos , Ácido Tranexámico/administración & dosificación
14.
Clin Genet ; 88(2): 182-6, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25060751

RESUMEN

The prevalence of BRCA1 and BRCA2 mutations among unselected breast cancer patients in the Bahamas is 23%. It is beneficial to advise relatives of mutation carriers that they are candidates for genetic testing. Women who test positive are then eligible for preventive interventions, such as oophorectomy. It is not clear how often relatives of women with a mutation in the Bahamas wish to undergo genetic testing for the family mutation. Furthermore, it is not clear how best to communicate this sensitive information to relatives in order to maximize patient compliance. We offered genetic testing to 202 first-degree relatives of 58 mutation carriers. Of 159 women who were contacted by the proband or other family member, only 14 made an appointment for genetic testing (9%). In contrast, among 32 relatives who were contacted directly by the genetic counselor, 27 came for an appointment (84%). This study suggests that for recruitment of relatives in the Bahamas, direct contact by counselor is preferable to using the proband as an intermediary.


Asunto(s)
Proteína BRCA1/genética , Proteína BRCA2/genética , Tamización de Portadores Genéticos , Pruebas Genéticas , Difusión de la Información/métodos , Adulto , Anciano , Anciano de 80 o más Años , Bahamas , Neoplasias de la Mama/genética , Femenino , Asesoramiento Genético , Humanos , Persona de Mediana Edad , Neoplasias Ováricas/genética , Ovariectomía , Prevalencia , Adulto Joven
15.
Phys Rev Lett ; 114(10): 101301, 2015 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-25815919

RESUMEN

We report the results of a joint analysis of data from BICEP2/Keck Array and Planck. BICEP2 and Keck Array have observed the same approximately 400 deg^{2} patch of sky centered on RA 0 h, Dec. -57.5°. The combined maps reach a depth of 57 nK deg in Stokes Q and U in a band centered at 150 GHz. Planck has observed the full sky in polarization at seven frequencies from 30 to 353 GHz, but much less deeply in any given region (1.2 µK deg in Q and U at 143 GHz). We detect 150×353 cross-correlation in B modes at high significance. We fit the single- and cross-frequency power spectra at frequencies ≥150 GHz to a lensed-ΛCDM model that includes dust and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio r), using a prior on the frequency spectral behavior of polarized dust emission from previous Planck analysis of other regions of the sky. We find strong evidence for dust and no statistically significant evidence for tensor modes. We probe various model variations and extensions, including adding a synchrotron component in combination with lower frequency data, and find that these make little difference to the r constraint. Finally, we present an alternative analysis which is similar to a map-based cleaning of the dust contribution, and show that this gives similar constraints. The final result is expressed as a likelihood curve for r, and yields an upper limit r_{0.05}<0.12 at 95% confidence. Marginalizing over dust and r, lensing B modes are detected at 7.0σ significance.

16.
Heredity (Edinb) ; 114(5): 441-9, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25182222

RESUMEN

Fungal species play extremely important roles in ecosystems. Clustered at the base of the fungal kingdom are Microsporidia, a group of obligate intracellular eukaryotes infecting multiple animal lineages. Because of their large host spectrum and their implications in host population regulation, they influence food webs, and accordingly, ecosystem structure and function. Unfortunately, their ecological role is not well understood. Present also as highly resistant spores in the environment, their characterisation requires special attention. Different techniques based on direct isolation and/or molecular approaches can be considered to elucidate their role in the ecosystems, but integrating environmental and genomic data (for example, genome architecture, core genome, transcriptional and translational signals) is crucial to better understand the diversity and adaptive capacities of Microsporidia. Here, we review the current status of Microsporidia in trophic networks; the various genomics tools that could be used to ensure identification and evaluate diversity and abundance of these organisms; and how these tools could be used to explore the microsporidian life cycle in different environments. Our understanding of the evolution of these widespread parasites is currently impaired by limited sampling, and we have no doubt witnessed but a small subset of their diversity.


Asunto(s)
Biodiversidad , Genoma Fúngico , Microsporidios/genética , Animales , Elementos Transponibles de ADN , Ecosistema , Genómica , Insectos/microbiología
17.
Br J Cancer ; 110(9): 2178-86, 2014 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-24743706

RESUMEN

BACKGROUND: Molecular characteristics of cancer vary between individuals. In future, most trials will require assessment of biomarkers to allocate patients into enriched populations in which targeted therapies are more likely to be effective. The MRC FOCUS3 trial is a feasibility study to assess key elements in the planning of such studies. PATIENTS AND METHODS: Patients with advanced colorectal cancer were registered from 24 centres between February 2010 and April 2011. With their consent, patients' tumour samples were analysed for KRAS/BRAF oncogene mutation status and topoisomerase 1 (topo-1) immunohistochemistry. Patients were then classified into one of four molecular strata; within each strata patients were randomised to one of two hypothesis-driven experimental therapies or a common control arm (FOLFIRI chemotherapy). A 4-stage suite of patient information sheets (PISs) was developed to avoid patient overload. RESULTS: A total of 332 patients were registered, 244 randomised. Among randomised patients, biomarker results were provided within 10 working days (w.d.) in 71%, 15 w.d. in 91% and 20 w.d. in 99%. DNA mutation analysis was 100% concordant between two laboratories. Over 90% of participants reported excellent understanding of all aspects of the trial. In this randomised phase II setting, omission of irinotecan in the low topo-1 group was associated with increased response rate and addition of cetuximab in the KRAS, BRAF wild-type cohort was associated with longer progression-free survival. CONCLUSIONS: Patient samples can be collected and analysed within workable time frames and with reproducible mutation results. Complex multi-arm designs are acceptable to patients with good PIS. Randomisation within each cohort provides outcome data that can inform clinical practice.


Asunto(s)
Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/genética , Medicina de Precisión , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas/genética , Proteínas ras/genética , Anciano , Anciano de 80 o más Años , Biomarcadores de Tumor/análisis , Neoplasias Colorrectales/mortalidad , Análisis Mutacional de ADN , Supervivencia sin Enfermedad , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proteínas Proto-Oncogénicas p21(ras) , Resultado del Tratamiento
18.
Am J Transplant ; 14(1): 156-62, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24369024

RESUMEN

Cytomegalovirus (CMV) infection remains a major source of morbidity and mortality in solid organ transplant recipients. Killer immunoglobulin-like receptors(KIR) are genetically polymorphic natural killer(NK) cell receptors important in antiviral responses. A retrospective, single-center cohort study was performed to study the interaction of KIR genotype and primary control of CMV infection after transplantation.Time to first CMV viremia was determined for a cohort of 531 CMV serology donor positive/recipient negative solid organ transplant recipients. Of the KIR genes,KIR2DL3 and KIR2DS2 were most strongly associated with time to CMV viremia in random survival forest analysis. As KIR2DL3 and KIR2DS2 both interact with HLA-C1, these interactions were evaluated. Seventy six recipients were found to be positive for both KIR2DL3 and KIR2DS2 and expressed only HLA-C1 antigens in both recipient and donor. These patients had a substantially reduced hazard of CMV viremia in the first year after solid organ transplantation (hazard ratio 0.44, 95% CI 0.27­0.72, p=0.0012). In KIR2DL3+/KIR2DS2+/HLA-C1/1 recipients who received an organ from a non-C1/1 donor, this protective effect was not observed. These results improve our understanding of human NK cell function in primary CMV infection after transplant.


Asunto(s)
Infecciones por Citomegalovirus/inmunología , Antígenos HLA-C/inmunología , Células Asesinas Naturales/inmunología , Receptores KIR/genética , Trasplantes/virología , Viremia/inmunología , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Receptores de Células Asesinas Naturales , Estudios Retrospectivos
19.
Scand J Med Sci Sports ; 24(1): 129-35, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22515407

RESUMEN

Lower-extremity injury is common in soccer. A number of studies have begun to assess why specific lower-extremity injuries occur. However, currently few studies have examined how footwear affects lower-extremity mechanics. In order to address this question, 14 male (age: 22.1 ± 3.9 years, height: 1.77 ± 0.06 m, and mass: 73.3 ± 11.5 kg) and 14 female (age: 22.8 ± 3.1 years, height: 1.68 ± 0.07 m and mass: 64.4 ± 9.2 kg) competitive soccer players underwent a motion analysis assessment while performing a jump heading task. Each subject performed the task in three different footwear conditions (running shoe, bladed cleat, and turf shoe). Two-way analyses of variance were used to examine statistical differences in landing mechanics between the footwear conditions while controlling for gender differences. These comparisons were made during two different parts (prior to and following) of a soccer-specific jump heading task. A statistically significant interaction for the peak dorsiflexion angle (P = 0.02) and peak knee flexion angle (P = 0.05) was observed. Male soccer players exhibited a degree increase in dorsiflexion in the bladed cleat while female soccer players exhibited a three-degree reduction in peak knee flexion in the bladed cleat condition. Other main effects for gender and footwear were also observed. The results suggest that landing mechanics differ based upon gender, footwear, and the type of landing. Therefore, training interventions aimed at reducing lower-extremity injury should consider utilizing sport-specific footwear when assessing movement patterns.


Asunto(s)
Articulación del Tobillo/fisiología , Articulación de la Cadera/fisiología , Articulación de la Rodilla/fisiología , Zapatos , Fútbol/fisiología , Adolescente , Adulto , Traumatismos del Tobillo/prevención & control , Fenómenos Biomecánicos , Femenino , Humanos , Traumatismos de la Rodilla/prevención & control , Masculino , Factores Sexuales , Adulto Joven
20.
Scand J Med Sci Sports ; 24(6): 974-81, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24118495

RESUMEN

Asymmetries in sagittal plane knee kinetics have been identified as a risk factor for anterior cruciate ligament (ACL) re-injury. Clinical tools are needed to identify the asymmetries. This study examined the relationships between knee kinetic asymmetries and ground reaction force (GRF) asymmetries during athletic tasks in adolescent patients following ACL reconstruction (ACL-R). Kinematic and GRF data were collected during a stop-jump task and a side-cutting task for 23 patients. Asymmetry indices between the surgical and non-surgical limbs were calculated for GRF and knee kinetic variables. For the stop-jump task, knee kinetics asymmetry indices were correlated with all GRF asymmetry indices (P < 0.05), except for loading rate. Vertical GRF impulse asymmetry index predicted peak knee moment, average knee moment, and knee work (R(2) ≥ 0.78, P < 0.01) asymmetry indices. For the side-cutting tasks, knee kinetic asymmetry indices were correlated with the peak propulsion vertical GRF and vertical GRF impulse asymmetry indices (P < 0.05). Vertical GRF impulse asymmetry index predicted peak knee moment, average knee moment, and knee work (R(2) ≥ 0.55, P < 0.01) asymmetry indices. The vertical GRF asymmetries may be a viable surrogate for knee kinetic asymmetries and therefore may assist in optimizing rehabilitation outcomes and minimizing re-injury rates.


Asunto(s)
Lesiones del Ligamento Cruzado Anterior , Reconstrucción del Ligamento Cruzado Anterior , Articulación de la Rodilla/fisiopatología , Movimiento/fisiología , Adolescente , Fenómenos Biomecánicos , Femenino , Humanos , Cinética , Masculino , Valor Predictivo de las Pruebas , Recurrencia , Soporte de Peso
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