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1.
Front Sports Act Living ; 4: 1060851, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36685066

RESUMEN

Athlete health and wellbeing requires a holistic, multidimensional approach to understanding, supporting, and treating individual athletes. Building more supportive, inclusive, and equitable environments for the health and wellbeing of women and gender expansive people further requires gender-responsive approaches that promote broader cultural change. Feminist sport and exercise medicine practitioners, sports scientists, and social science researchers are increasingly coming together in their efforts to do this work. However, working across disciplines inevitably includes an array of ontological, epistemological, and political challenges. In this paper, we offer a curated 'dialogue' with a group of feminist scholars engaged in research and practice across disciplines, bringing them together to discuss some of the most pressing gendered issues in sport today (i.e., ACL injury, concussion, menstruation in sport, mental health, gender categories). In so doing, we amplify the voices of those working (empirically and clinically) at the disciplinary intersections of gender, sport and health, and learn about some of the current and future possibilities for transdisciplinary innovations and strategies for building (responsiveness to) cultural change.

2.
Br Dent J ; 228(3): 137-138, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-32060431
3.
Br Dent J ; 226(2): 85-86, 2019 01 25.
Artículo en Inglés | MEDLINE | ID: mdl-30679849
4.
Br J Oral Maxillofac Surg ; 57(2): 125-134, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30658870

RESUMEN

The ability of patients to participate in recreational activities is an important facet of health-related quality of life (HRQoL) after treatment for cancer of the head and neck. The aim of this study was to analyse patients' responses to the activity and recreation domains of the University of Washington quality of life questionnaire (UW-QoL), and to relate them to clinical characteristics, the intensity of leisure-time exercise/week, perceived barriers that interfere with exercise, and feeling able to participate in an exercise programme. Other questionnaires used were the Godin Leisure-Time Exercise questionnaire, the Perceived Exercise Barriers questionnaire, and the Exercise Preferences questionnaire. The survey sample comprised 1021 patients of whom 437 responded (43%). Of them, 9% reported a serious problem with activity and 8% with recreation. The main influencing factors were site (oropharynx), advanced stage, radiotherapy and chemotherapy, composite flap, gastrostomy tube, and coexisting conditions. Low (worse) scores in the UW-QoL activity and recreation domains were associated with little time spent exercising, low-intensity exercise, more barriers to exercising, and a lack of preference. The use of the UW-QoL in follow-up assessments can help to identify patients who are having difficulties in these two domains, as well as those who feel able to participate in an exercise programme. Further research is required to optimise the interventions that will promote exercise and improve recovery and wellbeing.


Asunto(s)
Neoplasias de Cabeza y Cuello , Calidad de Vida , Gastrostomía , Humanos , Recreación , Encuestas y Cuestionarios
5.
CJEM ; 18(3): 213-22, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26832320

RESUMEN

OBJECTIVE: Two major processes underlie human decision-making: experiential (intuitive) and rational (conscious) thinking. The predominant thinking process used by working paramedics and student paramedics to make clinical decisions is unknown. METHODS: A survey was administered to ground ambulance paramedics and to primary care paramedic students. The survey included demographic questions and the Rational Experiential Inventory-40, a validated psychometric tool involving 40 questions. Twenty questions evaluated each thinking style: 10 assessed preference and 10 assessed ability to use that style. Responses were provided on a five-point Likert scale, with higher scores indicating higher affinity for the style in question. Analysis included both descriptive statistics and t tests to evaluate differences in thinking style. RESULTS: The response rate was 88.4% (1172/1326). Paramedics (n=904) had a median age of 36 years (IQR 29-42) and most were male (69.5%) and primary or advanced care paramedics (PCP=55.5%; ACP=32.5%). Paramedic students (n=268) had a median age of 23 years (IQR 21-26), most were male (63.1%) and had completed high school (31.7%) or an undergraduate degree (25.4%) prior to paramedic training. Both groups scored their ability to use and favourability toward rational thinking significantly higher than experiential thinking. The mean score for rational thinking was 3.86/5 among paramedics and 3.97/5 among paramedic students (p<0.001). The mean score for experiential thinking was 3.41/5 among paramedics and 3.35/5 among paramedic students (p=0.06). CONCLUSION: Working paramedics and student paramedics prefer and perceive that they have the ability to use rational over experiential thinking. This information adds to our current knowledge on paramedic decision-making and is potentially important for developing continuing education and clinical support tools.


Asunto(s)
Técnicos Medios en Salud/psicología , Toma de Decisiones , Medicina de Emergencia/educación , Adulto , Estudios Transversales , Femenino , Humanos , Masculino , Nueva Escocia , Psicometría , Encuestas y Cuestionarios , Pensamiento
6.
CJEM ; 17(5): 484-90, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26062819

RESUMEN

BACKGROUND: A recent mixed-methods study on the state of emergency medical services (EMS) research in Canada led to the generation of nineteen actionable recommendations. As part of the dissemination plan, a survey was distributed to EMS stakeholders to determine the anticipated impact and feasibility of implementing these recommendations in Canadian systems. METHODS: An online survey explored both the implementation impact and feasibility for each recommendation using a five-point scale. The sample consisted of participants from the Canadian National EMS Research Agenda study (published in 2013) and additional EMS research stakeholders identified through snowball sampling. Responses were analysed descriptively using median and plotted on a matrix. Participants reported any planned or ongoing initiatives related to the recommendations, and required or anticipated resources. Free text responses were analysed with simple content analysis, collated by recommendation. RESULTS: The survey was sent to 131 people, 94 (71.8%) of whom responded: 30 EMS managers/regulators (31.9%), 22 researchers (23.4%), 15 physicians (16.0%), 13 educators (13.8%), and 5 EMS providers (5.3%). Two recommendations (11%) had a median impact score of 4 (of 5) and feasibility score of 4 (of 5). Eight recommendations (42%) had an impact score of 5, with a feasibility score of 3. Nine recommendations (47%) had an impact score of 4 and a feasibility score of 3. CONCLUSIONS: For most recommendations, participants scored the anticipated impact higher than the feasibility to implement. Ongoing or planned initiatives exist pertaining to all recommendations except one. All of the recommendations will require additional resources to implement.


Asunto(s)
Servicios Médicos de Urgencia/organización & administración , Política de Salud , Investigación sobre Servicios de Salud/métodos , Guías de Práctica Clínica como Asunto , Canadá , Estudios Transversales , Estudios de Factibilidad , Humanos , Estudios Retrospectivos , Encuestas y Cuestionarios
7.
Andrology ; 1(1): 57-66, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23258631

RESUMEN

Human normal spermatozoa present a specific chromatin organization, illustrated particularly by the non-random chromosome positioning. Spermatozoa with large vacuoles, described using motile sperm organelle morphology organization (MSOME), are associated with nuclear alterations, such as abnormal chromatin condensation and aneuploidy. To question a probable association between large nuclear vacuoles and chromatin disorganization, we evaluated chromosomes X, Y and 18 topography in normal spermatozoa (NS) compared with spermatozoa with large vacuoles (SLV). After centrifugation on a gradient density system, 229 NS (spermatozoa presenting a normal nuclear shape and a vacuole area <6.5% of head area) from 10 normal semen samples and 221 SLV (spermatozoa presenting a vacuole area >13% of head area) from 10 semen samples with teratozoospermia were selected using MSOME. A three-colour FISH was carried out using α-satellite centromeric probes for chromosomes X, Y and 18. For each chromosome, longitudinal and spatial positioning of centromeres was analysed. Distribution of each chromosome was non-random in NS and in SLV, whatever the methodology used. Using longitudinal positioning, distribution of chromosome 18 and chromosome Y centromeres did not differ significantly between SLV and NS. On the contrary, chromosome X centromeres were more frequently positioned in the posterior region of sperm nucleus in SLV (p = 0.01). Considering spatial positioning, distributions differed significantly between SN and SLV for chromosome Y (p = 0.02) and chromosome 18 (p < 10(-4) ) and marginally for chromosome X (p = 0.08). Our study concluded to a modification in chromosomes X, Y and 18 centromere topography between NS and SLV, representing a novel and supplementary evidence to argue chromatin disorganization in SLV.


Asunto(s)
Azoospermia/patología , Ensamble y Desensamble de Cromatina , Posicionamiento de Cromosoma , Cromosomas Humanos Par 18 , Cromosomas Humanos X , Cromosomas Humanos Y , Espermatozoides/patología , Vacuolas/patología , Adulto , Azoospermia/genética , Estudios de Casos y Controles , Forma del Núcleo Celular , Centrifugación por Gradiente de Densidad , Centrómero/patología , Distribución de Chi-Cuadrado , Humanos , Hibridación Fluorescente in Situ , Masculino , Ploidias , Motilidad Espermática
8.
Gynecol Obstet Fertil ; 40(11): 671-4, 2012 Nov.
Artículo en Francés | MEDLINE | ID: mdl-23102576

RESUMEN

Normal spermatogenesis results from a balance between process of cell proliferation, cell differentiation and apoptosis that concern somatic cells and germ cells. Dysfunction of spermatogenesis may be the result of constitutional or acquired abnormalities of spermatogonia stem cells or somatic cells. To overcome these problems, it seems necessary to implement preventive measures for germ stem cell preservation or substitute measures to replace them, the objective being to replicate in vivo or in vitro the process of spermatozoa production. This article will discuss the different experimental strategies for considering the in vivo or in vitro production of spermatozoa, outside the physiological process.


Asunto(s)
Espermátides/fisiología , Espermatogénesis/fisiología , Espermatozoides/fisiología , Animales , Apoptosis , Diferenciación Celular , Proliferación Celular , Humanos , Infertilidad Masculina , Masculino , Células de Sertoli/fisiología , Espermatozoides/anomalías , Células Madre/fisiología
9.
Philos Trans A Math Phys Eng Sci ; 370(1969): 2960-86, 2012 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-22615471

RESUMEN

The digital linear coding carried by the base pairs in the DNA double helix is now known to have an important component that acts by altering, along its length, the natural shape and stiffness of the molecule. In this way, one region of DNA is structurally distinguished from another, constituting an additional form of encoded information manifest in three-dimensional space. These shape and stiffness variations help in guiding and facilitating the DNA during its three-dimensional spatial interactions. Such interactions with itself allow communication between genes and enhanced wrapping and histone-octamer binding within the nucleosome core particle. Meanwhile, interactions with proteins can have a reduced entropic binding penalty owing to advantageous sequence-dependent bending anisotropy. Sequence periodicity within the DNA, giving a corresponding structural periodicity of shape and stiffness, also influences the supercoiling of the molecule, which, in turn, plays an important facilitating role. In effect, the super-helical density acts as an analogue regulatory mode in contrast to the more commonly acknowledged purely digital mode. Many of these ideas are still poorly understood, and represent a fundamental and outstanding biological question. This review gives an overview of very recent developments, and hopefully identifies promising future lines of enquiry.


Asunto(s)
Computadores Moleculares , Cristalización/métodos , ADN/química , ADN/ultraestructura , Modelos Químicos , Modelos Genéticos , Modelos Moleculares , Procesamiento de Señales Asistido por Computador , Relación Estructura-Actividad
10.
Theriogenology ; 76(6): 981-90, 2011 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-21664672

RESUMEN

Fertility preservation has been included in the management of childhood cancer treatment. Cryopreservation of immature testicular tissue is the only available solution for pre-pubertal boys. Different freezing protocols have been developed in several species but without a clearly identified procedure. We tried to evaluate several protocols for cryopreservation of rat immature testicular tissue. Twelve different freezing protocols using different (i) cryoprotectant (dimethylsulphoxide [DMSO] or 1,2-propanediol [PROH]), (ii) cryoprotectant concentration (1.5M or 3M), (iii) equilibration time (30 or 60 min), (iv) equilibration temperature (4 °C or room temperature), (v) size of testicular fragment (7.5mg or 15 mg), (vi) package (straws or cryovials), were compared using cord morphological damage evaluation. A testicular tissue piece of 7.5mg cryopreserved in cryovial using 1.5M DMSO, an equilibration time of 30 min at 4 °C showed fewer morphological alterations than the other protocols tested. The selected freezing protocol was able to maintain rat immature testicular tissue architecture, functionality after testicular pieces organotypic culture, and could be proposed in a human application.


Asunto(s)
Criopreservación/veterinaria , Ratas , Testículo/anatomía & histología , Conservación de Tejido/veterinaria , Animales , Proliferación Celular , Criopreservación/métodos , Crioprotectores , Dimetilsulfóxido , Masculino , Técnicas de Cultivo de Tejidos/veterinaria , Conservación de Tejido/métodos
11.
Hum Reprod ; 26(1): 47-58, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21088015

RESUMEN

BACKGROUND: Spermatozoa with large vacuoles (SLV) may have a negative impact on embryo development. The origin of these vacuoles is unknown. We evaluated acrosome and nucleus alterations in isolated SLV, versus unselected spermatozoa. METHODS: We studied 20 patients with teratozoospermia. Spermatozoa from the native semen sample and spermatozoa presenting a vacuole occupying >13.0% total head area, isolated under high magnification (×6600), were assessed. Confocal and transmission electron microscope evaluations were performed on SLV and native sperm, respectively. Acrosome morphology and DNA fragmentation were analysed using proacrosin immunolabelling (monoclonal antibody 4D4) and terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling assay. Chromatin condensation was evaluated with aniline blue staining. Sperm aneuploidy was assessed using fluorescence in situ hybridization. RESULTS: SLV represented 38.0 ± 5.10% of motile spermatozoa obtained after gradient density centrifugation. Vacuoles were mainly in the anterior and median sperm head (45.7 ± 2.90 and 46.1 ± 3.00%, respectively). Abnormal acrosomes were increased in SLV compared with unselected spermatozoa (77.8 ± 2.49 versus 70.6 ± 2.62%; P = 0.014). Microscopic observations showed an exclusively nuclear localization of large vacuoles. Complete DNA fragmentation was higher in native spermatozoa (P < 0.0001) than SLV, while chromatin condensation was altered in SLV (P < 0.0001). Aneuploidy and diploidy rates were increased in SLV (P < 0.0001). CONCLUSIONS: Sperm vacuoles were exclusively nuclear. In our selected teratozoospermic population, aneuploidy and chromatin condensation defects were the main alterations observed in SLV. Based on results from this small sample of spermatozoa, we propose a global impairment of the spermatogenesis process as a common origin of the morphological alterations.


Asunto(s)
Acrosoma/ultraestructura , Infertilidad Masculina/patología , Análisis de Semen/métodos , Espermatozoides/ultraestructura , Vacuolas/ultraestructura , Adulto , Aneuploidia , Núcleo Celular/ultraestructura , Cromatina/ultraestructura , Fragmentación del ADN , Desarrollo Embrionario , Humanos , Hibridación Fluorescente in Situ , Etiquetado Corte-Fin in Situ , Masculino , Microscopía Electrónica de Transmisión , Persona de Mediana Edad
12.
J Androl ; 31(6): 617-30, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20203335

RESUMEN

Numerous parameters have to be tested to identify optimal conditions for prepubertal testicular tissue banking. Our study evaluated 19 different cryopreservation conditions for immature testicular tissue using a rapid screening method. Immature mice testes were cryopreserved using either 1,2-propanediol (PROH) or dimethyl sulfoxide (DMSO) at a concentration of 0.75 or 1.5 M using a controlled slow-cooling rate protocol with (S+) or without seeding (S+). Equilibration was performed either at room temperature or at 4°C for 15 or 30 minutes. Seminiferous cord cryodamage was determined by scoring morphologic alterations. Cell proliferation ability was evaluated using a proliferating cell nuclear antigen (PCNA) antibody. Testes cryopreserved with optimal conditions were grafted into immunodeficient mice. The highest proportions of PCNA-positive nuclei and lowest morphologic alterations were observed with 1.5 M DMSO. Tissues were more altered with 0.75 M DMSO or PROH. Complete germ cell maturation was observed after allografting of testicular pieces previously frozen with 1.5 M DMSO, S+, 30 minutes. The 1.5 M DMSO, S+ or S+ protocol preserved prepubertal mice testicular tissue architecture and germ cell and Sertoli cell proliferation potential. Allografting of thawed testis fragments into immunodeficient mice confirmed that the 1.5 M DMSO, S+, 30 minutes protocol maintained testicular somatic and germ cell functions. Postthaw histologic evaluation and PCNA immunostaining are useful to rapidly test numerous freeze-thaw parameters. They may also be efficient tools to control human prepubertal frozen testis quality, within the context of a clinical application.


Asunto(s)
Criopreservación/métodos , Antígeno Nuclear de Célula en Proliferación/metabolismo , Testículo/citología , Animales , Supervivencia Celular , Crioprotectores/farmacología , Dimetilsulfóxido/administración & dosificación , Masculino , Ratones , Ratones Desnudos , Antígeno Nuclear de Célula en Proliferación/análisis , Propilenglicol/farmacología , Testículo/efectos de los fármacos , Testículo/fisiología
13.
Philos Trans A Math Phys Eng Sci ; 362(1820): 1265-79, 2004 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-15306450

RESUMEN

This article gives an overview of recent research on the mechanical properties and spatial deformations of the DNA molecule. Globally the molecule behaves like a uniform elastic rod, and its twisting and writhing govern its compaction and packaging within a cell. Meanwhile high mechanical stresses can induce structural transitions of DNA giving, for example, a phase diagram in the space of the applied tension and torque. Locally, the mechanical properties vary according to the local sequence organization. These variations play a vital role in the biological functioning of the molecule.


Asunto(s)
Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/ultraestructura , ADN/química , ADN/ultraestructura , Modelos Moleculares , Secuencia de Bases , Elasticidad , Datos de Secuencia Molecular , Movimiento (Física) , Conformación de Ácido Nucleico , Desnaturalización de Ácido Nucleico , Estrés Mecánico , Relación Estructura-Actividad , Torque
14.
Philos Trans A Math Phys Eng Sci ; 362(1820): 1423-38, 2004 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-15306459

RESUMEN

Although the average physico-chemical properties of a long DNA molecule may approximate to those of a thin isotropic homogeneous rod, DNA behaves more locally as an anisotropic heterogeneous rod. This bending anisotropy is sequence dependent and to a first approximation reflects both the geometry and stability of individual base steps. The biological manipulation and packaging of the molecule often depend crucially on local variations in both bending and torsional flexibility. However, whereas the probability of DNA untwisting can be strongly correlated with a high bending flexibility, DNA bending, especially when the molecule is tightly wrapped on a protein surface, may be energetically favoured by a less flexible sequence whose preferred configuration conforms more closely to that of the complementary protein surface. In the latter situation the lower bending flexibility may be more than compensated for on binding by a reduced required deformation energy relative to a fully isotropic DNA molecule.


Asunto(s)
Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/ultraestructura , ADN/química , ADN/ultraestructura , Modelos Moleculares , Secuencia de Bases , Elasticidad , Datos de Secuencia Molecular , Movimiento (Física) , Conformación de Ácido Nucleico , Desnaturalización de Ácido Nucleico , Estrés Mecánico , Relación Estructura-Actividad , Torque
15.
N Engl J Med ; 351(7): 637-46, 2004 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-15306665

RESUMEN

BACKGROUND: The rate of survival after out-of-hospital cardiac arrest is low. It is not known whether this rate will increase if laypersons are trained to attempt defibrillation with the use of automated external defibrillators (AEDs). METHODS: We conducted a prospective, community-based, multicenter clinical trial in which we randomly assigned community units (e.g., shopping malls and apartment complexes) to a structured and monitored emergency-response system involving lay volunteers trained in cardiopulmonary resuscitation (CPR) alone or in CPR and the use of AEDs. The primary outcome was survival to hospital discharge. RESULTS: More than 19,000 volunteer responders from 993 community units in 24 North American regions participated. The two study groups had similar unit and volunteer characteristics. Patients with treated out-of-hospital cardiac arrest in the two groups were similar in age (mean, 69.8 years), proportion of men (67 percent), rate of cardiac arrest in a public location (70 percent), and rate of witnessed cardiac arrest (72 percent). No inappropriate shocks were delivered. There were more survivors to hospital discharge in the units assigned to have volunteers trained in CPR plus the use of AEDs (30 survivors among 128 arrests) than there were in the units assigned to have volunteers trained only in CPR (15 among 107; P=0.03; relative risk, 2.0; 95 percent confidence interval, 1.07 to 3.77); there were only 2 survivors in residential complexes. Functional status at hospital discharge did not differ between the two groups. CONCLUSIONS: Training and equipping volunteers to attempt early defibrillation within a structured response system can increase the number of survivors to hospital discharge after out-of-hospital cardiac arrest in public locations. Trained laypersons can use AEDs safely and effectively.


Asunto(s)
Reanimación Cardiopulmonar , Cardioversión Eléctrica , Servicios Médicos de Urgencia , Paro Cardíaco/terapia , Voluntarios , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Comercio , Femenino , Paro Cardíaco/mortalidad , Hospitalización , Vivienda , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Método Simple Ciego , Análisis de Supervivencia
16.
Reproduction ; 123(4): 507-15, 2002 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11914113

RESUMEN

Embryo transfer and pregnancy maintenance strategies in pigs were evaluated with reference to situations in which limited numbers of viable embryos or micromanipulated embryos are available, such as pig cloning. Development of embryos with compromised zona pellucida was compared with development of embryos with intact zona pellucida. Micromanipulation had no effect on blastocyst production rates after development in vivo or in vitro, but development in vivo improved the number of embryos reaching the blastocyst stage. Transfer of embryos with compromised zona pellucida resulted in live piglets. Several hormone treatments to maintain pregnancy were tested in a model in which three embryos were transferred into unmated recipient gilts, compared with transfer of three embryos into mated recipients. None of the hormonal treatments resulted in pregnancy rates of more than 25% at term and no more than 9% of transferred embryos survived, in comparison with 50% of the mated recipients successfully carrying 25% of transferred embryos. Lastly, the developmental potential of parthenogenetic embryos was assessed and 62% of transferred embryos resulted in pregnancies, none of which continued beyond day 55 of gestation. After co-transfer of three fertilized embryos with 55-60 parthenogenetic embryos into each of six recipients, two live piglets were delivered. The results from the present study indicate that transfer of zona pellucida compromised embryos can yield litters of normal piglets. In addition, it was demonstrated in a model system involving the transfer of three fertilized embryos into mature gilts that hormonal pregnancy maintenance strategies support a low proportion of embryos to term. Lastly, the present study shows for the first time a comparably effective but novel alternative for pregnancy maintenance in the pig involving the co-transfer of parthenote embryos.


Asunto(s)
Clonación de Organismos , Transferencia de Embrión/veterinaria , Desarrollo Embrionario y Fetal/fisiología , Porcinos , Animales , Técnicas de Cultivo de Célula , Femenino , Embarazo , Zona Pelúcida/fisiología
17.
EMBO Rep ; 2(12): 1089-94, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11743021

RESUMEN

dMi-2, the ATPase subunit of the Drosophila nucleosome remodelling and histone deacetylation (dNuRD) complex, was identified in a two-hybrid screen as an interacting partner of the transcriptional repressor, Tramtrack69 (Ttk69). A short region of Ttk69 is sufficient to mediate this interaction. Ttk69, but not the Ttk88 isoform, co-purifies with the dNuRD complex isolated from embryo extracts. dMi-2 and Ttk69 co-immunoprecipitate from embryonic extracts, indicating that they can associate in vivo. Both dMi-2 and Ttk69 co-localize at a number of discrete sites on polytene chromosomes, showing that they bind common target loci. We also demonstrate that dMi-2 and Ttk interact genetically, indicating a functional interaction in vivo. We propose that Ttk69 represses some target genes by remodelling chromatin structure through the recruitment of the dNuRD complex.


Asunto(s)
Adenosina Trifosfatasas , Autoantígenos/metabolismo , Proteínas Portadoras/metabolismo , Cromatina/metabolismo , Proteínas de Drosophila , Drosophila , Histona Desacetilasas/química , Histona Desacetilasas/metabolismo , Proteínas Represoras/metabolismo , Animales , Autoantígenos/genética , Western Blotting , Proteínas Portadoras/genética , Cromatina/química , Cromatina/genética , Drosophila/genética , Drosophila/metabolismo , Regulación de la Expresión Génica , Complejo Desacetilasa y Remodelación del Nucleosoma Mi-2 , Unión Proteica , Subunidades de Proteína , Proteínas Represoras/genética , Técnicas del Sistema de Dos Híbridos , Levaduras
18.
Ann Emerg Med ; 38(5): 518-26, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11679863

RESUMEN

STUDY OBJECTIVE: The objective of this study was to examine the scientific quality of systematic reviews published in 5 leading emergency medicine journals. METHODS: MEDLINE and EMBASE databases were electronically searched to identify published systematic reviews. Searches were only conducted in emergency medicine journals during the past 10 years; 4 of the journals were also hand searched. Potential reviews were assessed independently by 2 reviewers for inclusion. Data regarding methods were extracted from each review independently by 2 reviewers. All systematic reviews were retrieved and rated for quality by using the 10 questions from the overview quality assessment questionnaire. RESULTS: Twenty-nine reviews were identified from more than 100 citations. The overall scientific quality of the systematic reviews was low (mean score, 2.7; 95% confidence interval 2.1 to 3.2; maximum possible score, 7.0). Selection and publication biases were rarely addressed in this collection of reviews. For example, the search strategies were only identified in 9 (31%) reviews, whereas independent study selection (6 [21%]) and quality assessment of included studies (9 [31%]) were infrequently performed. Overall, the majority of reviews had extensive flaws, and only 3 (10%) had minimal flaws. CONCLUSION: The results of the study indicate that many of the systematic reviews published in the emergency medicine literature contain major flaws; reviews with poor methodology may limit the validity of reported results. Further efforts should be made to improve the design, reporting, and publication of systematic reviews in emergency medicine.


Asunto(s)
Medicina de Emergencia , Publicaciones Periódicas como Asunto , Edición/normas , Garantía de la Calidad de Atención de Salud , Literatura de Revisión como Asunto , Humanos , Sistemas de Información , MEDLINE , Control de Calidad , Estados Unidos
19.
J Mol Biol ; 309(1): 79-88, 2001 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-11491303

RESUMEN

DNA minicircles, where the length of DNA is below the persistence length, are highly effective, preferred, ligands for HMG-box proteins. The proteins bind to them "structure-specifically" with affinities in the nanomolar range, presumably to an exposed widened minor groove. To understand better the basis of this preference, we have studied the binding of HMG1 (which has two tandem HMG boxes linked by a basic extension to a long acidic tail) and Drosophila HMG-D (one HMG box linked by a basic region to a short and less acidic tail), and their HMG-box domains, to 88 bp and 75 bp DNA minicircles. In some cases we see cooperative binding of two molecules to the circles. The requirements for strong cooperativity are two HMG boxes and the basic extension; the latter also appears to stabilize and constrain the complex, preventing binding of further protein molecules. HMG-D, with a single HMG box, does not bind cooperatively. In the case of HMG1, the acidic tail is not required for cooperativity and does not affect binding significantly, in contrast to a much greater effect with linear DNA, or even four-way junctions (another distorted DNA substrate). Such effects could be relevant in the hierarchy of binding of HMG-box proteins to DNA distortions in vivo, where both single-box and two-box proteins might co-exist, with or without basic extensions and acidic tails.


Asunto(s)
ADN Circular/química , ADN Circular/metabolismo , Proteínas del Grupo de Alta Movilidad/química , Proteínas del Grupo de Alta Movilidad/metabolismo , Conformación de Ácido Nucleico , Sitio Alostérico , Animales , ADN Circular/genética , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/metabolismo , Drosophila , Unión Proteica , Estructura Terciaria de Proteína , Especificidad por Sustrato , Termodinámica
20.
J Biol Chem ; 276(40): 37569-76, 2001 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-11473125

RESUMEN

HMG-D is an abundant chromosomal protein associated with condensed chromatin during the first nuclear cleavage cycles of the developing Drosophila embryo. We previously suggested that HMG-D might substitute for the linker histone H1 in the preblastoderm embryo and that this substitution might result in the characteristic less compacted chromatin. We have now studied the association of HMG-D with chromatin using a cell-free system for chromatin reconstitution derived from Drosophila embryos. Association of HMG-D with chromatin, like that of histone H1, increases the nucleosome spacing indicative of binding to the linker DNA between nucleosomes. HMG-D interacts with DNA during the early phases of nucleosome assembly but is gradually displaced as chromatin matures. By contrast, purified chromatin can be loaded with stoichiometric amounts of HMG-D, and this can be displaced upon addition of histone H1. A direct physical interaction between HMG-D and histone H1 was observed in a Far Western analysis. The competitive nature of this interaction is reminiscent of the apparent replacement of HMG-D by H1 during mid-blastula transition. These data are consistent with the hypothesis that HMG-D functions as a specialized linker protein prior to appearance of histone H1.


Asunto(s)
Cromatina/metabolismo , ADN/metabolismo , Drosophila/embriología , Proteínas del Grupo de Alta Movilidad/metabolismo , Histonas/metabolismo , Animales , Sistema Libre de Células , Proteínas de Insectos/metabolismo , Nucleosomas/metabolismo
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