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1.
Med Probl Perform Art ; 37(3): 151-164, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-36053493

RESUMEN

OBJECTIVE: Pole dancing is a challenging physical activity. Prospective injury studies in pole dancing are lacking. The aim of this study was to describe the incidence, mechanisms, and characteristics of injuries in pole dancers. METHODS: A total of 66 pole dancers from 41 studios across Australia were prospectively followed over 12 months. An intake questionnaire was administered including items on pole dancers' demographics and training characteristics. Exposure was assessed using a daily online training diary. Self-reported injury data were collected via an incident report form and subsequently coded using the Orchard Sports Injury Classification System. Injuries occurring during pole-specific and pole-related activities were included in the analyses. RESULTS: The sample included 63 females and 3 males, mean age 32.3 ± 8.9 years and mean pole training experience 3.5 ± 2.8 years. 25 of 66 participants completed the full study. The 1-year incidence of all new injuries was 8.95/1,000 exposure hours (95% CI 6.94 - 10.96), 7.65/1,000 hrs (95% CI 5.79 - 9.51) for pole-specific injuries and 1.29/1,000 hrs (95% CI 0.53 - 2.06) for pole-related injuries. A total of 103 injuries occurred, 62.1% of which were sudden onset and 37.9% gradual onset. Mechanism of onset included 54.4% acute and 45.6% repetitive in nature. Shoulder (20.4%) and thigh (11.7%, majority ham¬string) were the most reported anatomic injury sites. Non-contact mechanisms accounted for the majority of injuries (57.3%). The most reported primary contributor to injury onset at the shoulder were manoeuvres characterised by loaded internal humeral rotation (33.3%), and at the hamstring were manoeuvres and postures involving front splits (100.0%). CONCLUSION: The findings indicate that pole dancers are at high risk for injuries. Future research is needed to understand the biomechani¬cal demand of manoeuvres and training characteristics of pole dancing (e.g., workload and recovery) to guide the development of preventative interventions, particularly targeted toward the shoulder and hamstring.


Asunto(s)
Traumatismos en Atletas , Baile , Músculos Isquiosurales , Adulto , Traumatismos en Atletas/epidemiología , Baile/lesiones , Femenino , Humanos , Incidencia , Masculino , Estudios Prospectivos , Factores de Riesgo , Adulto Joven
2.
Med Probl Perform Art ; 35(3): 121-129, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32870963

RESUMEN

AIMS: This study investigated the extent and characteristics of mental health issues in contemporary dance students, as clear insight into these health problems is lacking. METHODS: During one academic year, 134 dance and dance-teacher students were monitored on a monthly basis using the Performing artist and Athlete Health Monitor (PAHM). RESULTS: In total, 130 students were included in the analyses, comprising 81 dance students and 49 dance-teacher students. The response rate of the monthly questionnaires was 79.7%. Overall, 96.9% of the students reported at least one physical/mental health problem. The incidence proportion (IP) of all reported mental health issues for one academic year was 44.6% (n=58). Furthermore, 29.2% of the students reported a mental health issue as their most severe health problem, of whom 39.4% indicated a substantial mental health issue (i.e., problems leading to moderate, severe, or complete reductions in training volume or performance). The monthly IP of mental health issues ranged from 2.9 to 8.9% and 0 to 5.3% for substantial mental health issues. The most reported types of mental health issues were general anxiety (20.0%), stress due to external factors (18.3%), and constant tiredness (16.7%). Dance-teacher students of all study years and second-year students from both educational programs indicated significantly more mental health issues, while sex showed no significant differences. CONCLUSIONS: Contemporary dance students are at risk of mental health issues. Dance schools should pay special attention to stress, anxiety, and (constant) tiredness of their students. More research is needed to gain insight into specific characteristics and risk factors of mental health issues in dance students.


Asunto(s)
Baile , Salud Mental , Baile/psicología , Humanos , Instituciones Académicas , Estudiantes , Encuestas y Cuestionarios
3.
Scand J Med Sci Sports ; 27(12): 1978-1985, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28139042

RESUMEN

Injuries can have a major impact on the physical performance and academic career of physical education teacher education (PETE) students. To investigate the injury problem, risk factors, and the impact of injuries on academic success, 252 PETE students were followed during their first semester. Risk factor analysis was conducted by means of logistic regression analysis with a differentiation for upper body, lower body, acute, overuse, and severe injuries. An incidence of 1.26 injuries/student/semester was found. Most injuries involved the lower body (61%), were new injuries (76%), occurred acutely (66%), and were sustained during curricular gymnastics (25%) or extracurricular soccer (28%). Significant risk factors for lower body acute injuries were age (OR=2.14; P=.01), previous injury (OR=2.23; P=.01), and an injury at the start of the year (OR=2.56; P=.02). For lower body overuse injuries, gender (OR=2.85; P=.02) and the interval shuttle run test score (OR=2.44; P=.04) were significant risk factors. Previous injury (OR=2.59; P=.04) and injury at the start of the year (upper body: OR=4.57; P=.02; lower body: OR=3.75; P<.01) were risk factors for severe injuries. Injury-related time loss was positively related to total academic success (r=.20; P=.02) and success in theoretical courses (r=.24; P=<.01). No association was found between time loss and academic success for sport courses.


Asunto(s)
Éxito Académico , Traumatismos en Atletas/epidemiología , Educación y Entrenamiento Físico , Estudiantes , Adolescente , Trastornos de Traumas Acumulados/epidemiología , Femenino , Gimnasia/lesiones , Humanos , Incidencia , Masculino , Estudios Prospectivos , Factores de Riesgo , Fútbol/lesiones , Universidades , Adulto Joven
4.
Eur J Vasc Endovasc Surg ; 52(4): 487-499, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27543385

RESUMEN

OBJECTIVE: Experimental animal models have been used to investigate the formation, development, and progression of abdominal aortic aneurysms (AAAs) for decades. New models are constantly being developed to imitate the mechanisms of human AAAs and to identify treatments that are less risky than those used today. However, to the authors' knowledge, there is no model identical to the human AAA. The objective of this systematic review was to assess the different types of animal models used to investigate the development, progression, and treatment of AAA and to highlight their advantages and limitations. METHODS: A search protocol was used to perform a systematic literature search of PubMed and Embase. A total of 2,830 records were identified. After selection of the relevant articles, 564 papers on animal AAA models were included. RESULTS: The most common models in rodents, including elastase, calcium chloride, angiotensin II, xenograft, and transgenic models, and the most common models in non-rodents, including chemically induced, graft models, and patch models, all have limitations with regard to the pathological interpretation of human AAA. CONCLUSION: Although findings from animal models of AAAs cannot be directly translated to human AAAs, the identification and awareness of animal models of AAA will provide knowledge for further investigation and insight into human AAA disease.


Asunto(s)
Aneurisma de la Aorta Abdominal/fisiopatología , Aneurisma de la Aorta Abdominal/terapia , Modelos Animales de Enfermedad , Animales , Aorta Abdominal/patología , Aorta Abdominal/fisiopatología , Aneurisma de la Aorta Abdominal/patología , Estudios de Factibilidad , Humanos , Especificidad de la Especie
5.
Br J Sports Med ; 49(7): 448-52, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25573616

RESUMEN

BACKGROUND: The European Youth Olympic Festival (EYOF) is a biennial sporting event of nine Olympic Summer Sports for talented athletes, aged 13-18 years, from all over Europe. OBJECTIVE: To analyse the injuries and illnesses that occurred during the multisport event (14-19 July 2013), with the long-term aim of enabling international sports federations, the National Olympic Committees, and the European Olympic Committee to improve protection of athletes' health in youth. METHODS: Daily occurrence or non-occurrence of injuries and illnesses was recorded by using the IOC injury and illness surveillance system for multisport events. All National Olympic Committee physicians and healthcare providers and physicians of the Local Organizing Committee were invited to participate. RESULTS: In total, 2272 athletes from 49 countries took part in the EYOF 2013. During the five competition days of EYOF, 207 injuries and 46 illnesses were reported, resulting in an incidence of 91.1 injuries and 20.2 illnesses per 1000 athletes. Almost 10% of the athletes sustained at least one injury or illness. CONCLUSIONS: This study is the first multisport surveillance study on injuries and illnesses during the EYOF or any other summer Games organised for youth elite athletes. The data form the basis for further research on risk factors and injury mechanisms for this cohort. This research is needed to gain more knowledge and finally to implement effective injury and illness prevention measures.


Asunto(s)
Traumatismos en Atletas/epidemiología , Medicina Deportiva/estadística & datos numéricos , Adolescente , Aniversarios y Eventos Especiales , Europa (Continente)/epidemiología , Femenino , Enfermedades Gastrointestinales/epidemiología , Humanos , Infecciones/epidemiología , Masculino , Países Bajos/epidemiología , Estudios Prospectivos , Enfermedades Respiratorias/epidemiología
6.
Atheroscler Plus ; 48: 8-11, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36644559

RESUMEN

Background and aims: Recent technological advances have established vascular smooth muscle cells (SMCs) as central players in atherosclerosis. Increasingly complex genetic mouse models have unveiled that 30-70% of cells in experimentally induced atherosclerotic lesions derive from a handful of medial SMCs, and that these can adopt a broad range of plaque cell phenotypes. Most of these models are based on the SMMHC-CreER T2 mouse line as Cre-driver. Importantly, Cre-activation can be controlled in time (by administration of tamoxifen, TAM), which is critical to avoid unwanted effects of premature recombination events. The aim of this study was to scrutinize an unexpected observation of TAM-independent Cre-activity in this mouse line. Methods: Cre-activity was assessed by PCR in tissues from SMMHC-CreER T2 mice crossed with mice homozygous for loxP-flanked (floxed) exon 4 of Ccn2 (our gene-of-interest), and Ccn2 protein was measured in aortas by targeted mass spectrometry. Results: We observed spontaneous near-complete excision of floxed Ccn2 in aortas from adult mice that were not treated with TAM. As a result, Ccn2 protein was significantly reduced in aortas from these mice, but not to the same extent as TAM-treated littermates. Remarkably, most of the excision was completed in 4-week-old mice. Excision was Cre-dependent, as knockout bands were negligible in heart and liver (dominated by non-SMCs) of these mice, and undetectable in the aorta in the absence of Cre. Conclusion: Our observations warrant caution, and we advocate inclusion of appropriate controls (i.e., TAM-untreated mice) in future studies.

7.
Front Psychol ; 12: 581578, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33868071

RESUMEN

Background: People with a personality disorder (PD) suffer from enduring inflexible patterns in cognitions and emotions, leading to significant subjective distress, affecting both self and interpersonal functioning. In clinical practice, Dance Movement Therapy (DMT) is provided to clients with a PD, and although research continuously confirms the value of DMT for many populations, to date, there is very limited information available on DMT and PD. For this study, a systematic literature review on DMT and PD was conducted to identify the content of the described DMT interventions and the main treatment themes to focus upon in DMT for PD. Methods: A systematic search was conducted across the following databases: EMBASE, MEDLINE, PubMed, WEB OF SCIENCE, PsycINFO/OVID, and SCOPUS following the PRISMA guidelines. The Critical Appraisal Skills Programme for qualitative studies was used to rank the quality of the articles. The Oxford Center for Evidence-based Medicine standards were applied to determine the hierarchical level of best evidence. Quantitative content analysis was used to identify the intervention components: intended therapeutic goals, therapeutic activities leading to these goals, and suggested therapeutic effects following from these activities. A thematic synthesis approach was applied to analyze and formulate overarching themes. Results: Among 421 extracted articles, four expert opinions met the inclusion criteria. Six overarching themes were found for DMT interventions for PD: self-regulation, interpersonal relationships, integration of self, processing experiences, cognition, and expression and symbolization in movement/dance. No systematic descriptions of DMT interventions for PD were identified. A full series of intervention components could be synthesized for the themes of self-regulation, interpersonal relationships, and cognition. The use of body-oriented approaches and cognitive strategies was in favor of dance-informed approaches. Conclusions: Dance movement therapists working with PD clients focus in their interventions on body-related experiences, non-verbal interpersonal relationships, and to a lesser extent, cognitive functioning. A methodological line for all intervention components was synthesized for the themes of self-regulation, interpersonal relationships, and cognition, of importance for developing systematic intervention descriptions. Future research could focus on practitioners' expertise in applying DMT interventions for PD to develop systematic intervention descriptions and explore the suitability of the identified themes for clinical application. Clients' experiences could offer essential insights on how DMT interventions could address PD pathology and specific PD categories.

8.
J Sci Med Sport ; 24(11): 1123-1129, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33888428

RESUMEN

OBJECTIVES: Groin injuries are common in professional male football and result in significant complaints, time-loss and cost. We aimed to study: 1. Normal values of hip muscle strength and self-reported hip and groin function (Hip And Groin Outcome Score (HAGOS)). 2. Changes in these values throughout the season. 3. If previous (groin) injuries, leg dominance or league were associated with these outcome measures. DESIGN: Prospective cohort study. METHODS: 313 professional male football players (11 clubs) participated. Player characteristics and previous injuries were registered. Hip muscle strength (hand-held dynamometer) and HAGOS measurements were done at the start, middle and end of the season. RESULTS: Data from 217 players were analysed. Adduction strength (mean±standard deviation, Nm/Kg) was 3.40±0.72 (start), 3.30±0.65 (mid) and 3.39±0.74 (end) (p=0.186). Abduction strength was 3.45±0.67, 3.14±0.57 and 3.28±0.61 (p<0.001). Adduction/abduction ratio was 1.00±0.21, 1.07±0.22 and 1.05±0.23 (p<0.001). Statistically, the HAGOS-subscale 'Pain' (median [interquartile range]) deteriorated slightly during the season (p=0.005), especially from mid-season (97.5 [90.6-100.0]) to end-of-season (95.0 [87.5-100.0]) (p=0.003). Other subscale scores remained unchanged between time points; 85.7 (symptoms), 100.0 (daily living), 96.9 (sports and recreation) 100.0, (physical activities) and 90.0 (quality of life). Previous injuries were associated with lower HAGOS-scores. Dominant legs had higher abduction strength (p<0.001) and lower adduction/abduction ratio (p<0.001). No differences between leagues were found for hip muscle strength and HAGOS-scores. CONCLUSIONS: In Dutch male professional football players, hip muscle strength and HAGOS-scores remained relatively stable throughout the season. Pain increased slightly, which while statistically significant, was not clinically relevant.


Asunto(s)
Ingle/fisiología , Cadera/fisiología , Fuerza Muscular , Fútbol/fisiología , Adolescente , Adulto , Ingle/lesiones , Lesiones de la Cadera/fisiopatología , Humanos , Masculino , Países Bajos , Dolor/etiología , Dolor/fisiopatología , Estudios Prospectivos , Valores de Referencia , Autoinforme , Fútbol/lesiones , Adulto Joven
9.
Sci Rep ; 11(1): 12903, 2021 06 18.
Artículo en Inglés | MEDLINE | ID: mdl-34145342

RESUMEN

Abdominal aortic aneurysm (AAA) is a complex disease which is incompletely accounted for. Basement membrane (BM) Collagen IV (COL4A1/A2) is abundant in the artery wall, and several lines of evidence indicate a protective role of baseline COL4A1/A2 in AAA development. Using Col4a1/a2 hemizygous knockout mice (Col4a1/a2+/-, 129Svj background) we show that partial Col4a1/a2 deficiency augmented AAA formation. Although unchallenged aortas were morphometrically and biomechanically unaffected by genotype, explorative proteomic analyses of aortas revealed a clear reduction in BM components and contractile vascular smooth muscle cell (VSMC) proteins, suggesting a central effect of the BM in maintaining VSMCs in the contractile phenotype. These findings were translated to human arteries by showing that COL4A1/A2 correlated to BM proteins and VSMC markers in non-lesioned internal mammary arteries obtained from coronary artery bypass procedures. Moreover, in human AAA tissue, MYH11 (VSMC marker) was depleted in areas of reduced COL4 as assessed by immunohistochemistry. Finally, circulating COL4A1 degradation fragments correlated with AAA progression in the largest Danish AAA cohort, suggesting COL4A1/A2 proteolysis to be an important feature of AAA formation. In sum, we identify COL4A1/A2 as a critical regulator of VSMC phenotype and a protective factor in AAA formation.


Asunto(s)
Aneurisma de la Aorta Abdominal/etiología , Membrana Basal/metabolismo , Colágeno Tipo IV/deficiencia , Predisposición Genética a la Enfermedad , Alelos , Animales , Aneurisma de la Aorta Abdominal/metabolismo , Aneurisma de la Aorta Abdominal/patología , Biomarcadores , Biopsia , Colágeno Tipo IV/genética , Modelos Animales de Enfermedad , Ensayo de Inmunoadsorción Enzimática , Estudios de Asociación Genética , Genotipo , Inmunohistoquímica , Masculino , Ratones , Ratones Noqueados , Músculo Liso Vascular/metabolismo , Miocitos del Músculo Liso/metabolismo , Proteolisis , Proteoma , Proteómica/métodos
10.
J Am Chem Soc ; 131(22): 7496-7, 2009 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-19489635

RESUMEN

Ribonucleotide reductase (RNR) catalyzes the reduction of ribonucleotides to deoxyribonucleotides. Class I RNRs are composed of two homodimeric proteins, alpha2 and beta2. The class Ia E. coli beta2 contains dinuclear, antiferromagnetically coupled iron centers and one tyrosyl free radical, Y122*/beta2. Y122* acts as a radical initiator in catalysis. Redox-linked conformational changes may accompany Y122 oxidation and provide local control of proton-coupled electron transfer reactions. To test for such redox-linked structural changes, FT-IR spectroscopy was employed in this work. Reaction-induced difference spectra, associated with the reduction of Y122* by hydroxyurea, were acquired from natural abundance, (2)H(4) tyrosine, and (15)N tyrosine labeled beta2 samples. Isotopic labeling led to the assignment of a 1514 cm(-1) band to the upsilon19a ring stretching vibration of Y122 and of a 1498 cm(-1) band to the upsilon7a CO stretching vibration of Y122*. The reaction-induced spectra also exhibited amide I bands, at 1661 and 1652 cm(-1). A similar set of amide I bands, with frequencies of 1675 and 1651 cm(-1), was observed when Y* was generated by photolysis in a pentapeptide, which matched the primary sequence surrounding Y122. This result suggests that reduction of Y122* is linked with structural changes at nearby amide bonds and that this perturbation is mediated by the primary sequence. To explain these data, we propose that a structural perturbation of the amide bond is driven by redox-linked electrostatic changes in the tyrosyl radical aromatic ring.


Asunto(s)
Ribonucleótido Reductasas/química , Hidroxiurea/química , Modelos Moleculares , Oxidación-Reducción , Conformación Proteica , Ribonucleótido Reductasas/metabolismo , Espectroscopía Infrarroja por Transformada de Fourier , Electricidad Estática , Tirosina/análogos & derivados , Tirosina/química
11.
Science ; 271(5248): 477-81, 1996 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-8560260

RESUMEN

The ribonucleoside triphosphate reductase (RTPR) from Lactobacillus leichmannii catalyzes adenosylcobalamin (AdoCbl)-dependent nucleotide reduction, as well as exchange of the 5' hydrogens of AdoCbl with solvent. A protein-based thiyl radical is proposed as an intermediate in both of these processes. In the presence of RTPR containing specifically deuterated cysteine residues, the electron paramagnetic resonance (EPR) spectrum of an intermediate in the exchange reaction and the reduction reaction, trapped by rapid freeze quench techniques, exhibits narrowed hyperfine features relative to the corresponding unlabeled RTPR. The spectrum was interpreted to represent a thiyl radical coupled to cob(II)alamin. Another proposed intermediate, 5'-deoxyadenosine, was detected by rapid acid quench techniques. Similarities in mechanism between RTPR and the Escherichia coli ribonucleotide reductase suggest that both enzymes require a thiyl radical for catalysis.


Asunto(s)
Radicales Libres , Ribonucleótido Reductasas/metabolismo , Compuestos de Sulfhidrilo/metabolismo , Adenosina Trifosfato/metabolismo , Secuencia de Aminoácidos , Catálisis , Cobamidas/metabolismo , Desoxiadenosinas/metabolismo , Espectroscopía de Resonancia por Spin del Electrón , Cinética , Lactobacillus/enzimología , Ligandos , Modelos Químicos , Datos de Secuencia Molecular , Oxidación-Reducción , Ribonucleótido Reductasas/química , Solventes , Vitamina B 12/análogos & derivados , Vitamina B 12/metabolismo
12.
Science ; 245(4924): 1396-9, 1989 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-2476851

RESUMEN

Bleomycin is a metal- and oxygen-dependent DNA cleaver. The chemistry of DNA damage has been proposed to involve rate-limiting abstraction of the 4'-hydrogen. A DNA fragment has been prepared that contains [4'-2H]thymidine residues of high isotopic content. Primary kinetic isotope effects have been directly observed at individual thymidine residues with DNA sequencing technology.


Asunto(s)
Bleomicina , Daño del ADN , Secuencia de Bases , Deuterio , Hierro , Oxígeno , Relación Estructura-Actividad , Timidina
13.
Science ; 253(5017): 292-8, 1991 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-1650033

RESUMEN

Incubation of the apoB2 subunit of Escherichia coli ribonucleotide reductase with Fe2+ and O2 produces native B2, which contains the tyrosyl radical-dinuclear iron cluster cofactor required for nucleotide reduction. The chemical mechanism of this reconstitution reaction was investigated by stopped-flow absorption spectroscopy and by rapid freeze-quench EPR (electron paramagnetic resonance) spectroscopy. Two novel intermediates have been detected in the reaction. The first exhibits a broad absorption band centered at 565 nanometers. Based on known model chemistry, this intermediate is proposed to be a mu-peroxodiferric complex. The second intermediate exhibits a broad absorption band centered at 360 nanometers and a sharp, isotropic EPR signal with g = 2.00. When the reaction is carried out with 57Fe2+, this EPR signal is broadened, demonstrating that the intermediate is an iron-coupled radical. Variation of the ratio of Fe2+ to B2 in the reaction and comparison of the rates of formation and decay of the intermediates to the rate of formation of the tyrosyl radical (.Y122) suggest that both intermediates can generate .Y122. This conclusion is supported by the fact that both intermediates exhibit an increased lifetime in a mutant B2 subunit (B2-Y122F) lacking the oxidizable Y122. Based on these kinetic and spectroscopic data, a mechanism for the reaction is proposed. Unlike reactions catalyzed by heme-iron peroxidases, oxygenases, and model complexes, the reconstitution reaction appears not to involve high-valent iron intermediates.


Asunto(s)
Hierro/metabolismo , Oxígeno/metabolismo , Ribonucleótido Reductasas/metabolismo , Tirosina/metabolismo , Sitios de Unión , Espectroscopía de Resonancia por Spin del Electrón , Escherichia coli/enzimología , Cinética , Sustancias Macromoleculares , Modelos Teóricos , Espectrofotometría Ultravioleta , Factores de Tiempo
14.
Trends Biochem Sci ; 23(11): 438-43, 1998 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-9852763

RESUMEN

Ribonucleotide reductases (RNRs) are uniquely responsible for converting nucleotides to deoxynucleotides in all organisms. The cofactor of class-I RNRs comprises a di-iron cluster and a tyrosyl radical, and is essential for initiation of radical-dependent nucleotide reduction. Recently, much progress has been made in understanding the mechanism by which this cofactor is generated in vitro and in vivo, as well as the function of the tyrosyl radical in nucleotide reduction. The Escherichia coli RNR cofactor provides a paradigm for cofactors in other di-iron requiring or tyrosyl-radical-requiring proteins.


Asunto(s)
Radicales Libres , Ribonucleótido Reductasas/metabolismo , Tirosina/análogos & derivados , Escherichia coli/enzimología , Hierro/metabolismo , Modelos Químicos , Tirosina/metabolismo
15.
Trends Biochem Sci ; 26(2): 93-9, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11166566

RESUMEN

Ribonucleotide reductases (RNRs) catalyze the conversion of both purine and pyrimidine nucleotides to deoxynucleotides in all organisms and provide all the monomeric precursors essential for both DNA replication and repair. RNRs have been divided into three classes on the basis of their unique metallo-cofactors. The exquisitely controlled free radical chemistry used by all RNRs, and the commonality of the structures of the subunits where the nucleotide reduction process occurs, together provide compelling evidence for the importance of chemistry in the divergent evolution of RNRs from a common progenitor.


Asunto(s)
Evolución Molecular , Ribonucleótido Reductasas/química , Ribonucleótido Reductasas/clasificación , Ribonucleótido Reductasas/genética , Sitio Alostérico , Sitios de Unión , Catálisis , Escherichia coli/enzimología , Lactobacillus/enzimología , Modelos Químicos , Modelos Moleculares , Conformación Proteica , Estructura Terciaria de Proteína , Piruvato Quinasa/química
16.
Curr Opin Struct Biol ; 10(6): 731-6, 2000 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11114511

RESUMEN

The structures of a class III ribonucleotide reductase (RNR) and pyruvate formate lyase exhibit striking homology within their active site domains with respect to each other and to the previously published structure of a class I RNR. The common structures and the common complex-radical-based chemistry of these systems, as well as of the class II RNRs, suggest that RNRs evolved by divergent evolution and provide an essential link between the RNA and DNA world.


Asunto(s)
ADN/metabolismo , ARN/metabolismo , Ribonucleótido Reductasas/metabolismo , Acetiltransferasas/química , Acetiltransferasas/metabolismo , Catálisis , Ribonucleótido Reductasas/química , Relación Estructura-Actividad
17.
Nat Biotechnol ; 15(1): 63-7, 1997 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9035108

RESUMEN

A synthetic operon for polyhydroxyalkanoate (PHA) biosynthesis designed to yield high levels of PHA synthase activity in vivo was constructed by positioning a genetic fragment encoding beta-ketothiolase and acetoacetyl-CoA reductase behind a modified synthase gene containing an Escherichia coli promoter and ribosome binding site. Plasmids containing the synthetic operon and the native Alcaligenes eutrophus PHA operon were transformed into E. coli DH5 alpha and analyzed for polyhydroxybutyrate production. The molecular weight of polymer isolated from recombinant E. coli containing the modified synthase construct, determined by multiangle light scattering, was lower than that of the polymer from E. coli containing the native A. eutrophus operon. A further decrease in polyester molecular weight was observed with increased induction of the PHA biosynthetic genes in the synthetic operon. Comparison of the enzyme activity levels of PHA biosynthetic enzymes in a strain encoding the native operon with a strain possessing the synthetic operon indicates that the amount of polyhydroxyalkanoate synthase in a host organism plays a key role in controlling the molecular weight and the polydispersity of polymer.


Asunto(s)
Aciltransferasas/genética , Aciltransferasas/metabolismo , Escherichia coli/genética , Poliésteres/química , Poliésteres/metabolismo , Alcaligenes/genética , Alcaligenes/metabolismo , Sitios de Unión , Escherichia coli/crecimiento & desarrollo , Escherichia coli/metabolismo , Fermentación , Hidroxibutiratos/química , Hidroxibutiratos/metabolismo , Peso Molecular , Operón/genética , Regiones Promotoras Genéticas , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Ribosomas/genética , Ribosomas/metabolismo , Transcripción Genética , Transformación Bacteriana
18.
BMC Ophthalmol ; 7: 14, 2007 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-17877840

RESUMEN

BACKGROUND: Patients' feedback is of great importance in health care policy decisions. The Consumer Quality Index Cataract Questionnaire (CQI Cataract) was used to measure patients' experiences with quality of care after a cataract operation. This study aims to evaluate the reliability and the dimensional structure of this questionnaire and assesses its ability to measure differences between hospitals in patients' experiences with quality of care. METHODS: Survey data of 4,635 respondents were available. An exploratory factor analysis was performed to evaluate the construct validity of the questionnaire and item-correlations and inter-factor correlations were calculated. Secondly, Cronbach's alpha coefficients were calculated to assess the internal consistency of the scales. Thirdly, to evaluate the ability of the questionnaire to discriminate between hospitals, multilevel analyses were performed with patients hierarchically nested within hospitals. RESULTS: Exploratory factor analysis resulted in 14 quality of care items subdivided over three factors (i.e. communication with ophthalmologist, communication with nurses, and communication about medication). Cronbach's alpha coefficients of 0.89, 0.76 and 0.79 indicated good internal consistency. Multilevel analyses showed that the questionnaire was able to measure differences in patients' experiences with hospital care regarding communication with ophthalmologist and communication about medication. In addition, there was variation between hospitals regarding ophthalmologist ratings, hospital ratings and one dichotomous information item. CONCLUSION: These findings suggest that the CQI Cataract is a reliable and valid instrument. This instrument can be used to measure patients' experiences with three domains of hospital care after a cataract operation and is able to assess differences in evaluated care between hospitals.


Asunto(s)
Extracción de Catarata , Hospitalización , Pacientes , Calidad de la Atención de Salud , Encuestas y Cuestionarios , Adulto , Anciano , Análisis Factorial , Retroalimentación , Femenino , Hospitales/normas , Humanos , Masculino , Persona de Mediana Edad , Psicometría , Reproducibilidad de los Resultados , Encuestas y Cuestionarios/normas
19.
BMJ Open Sport Exerc Med ; 3(1): e000199, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28761701

RESUMEN

BACKGROUND: A thorough knowledge of the epidemiology and severity of injuries and illness in youth female elite sports is lacking due to the methodological challenges involved in recording them. In this study, the prevalence and incidence of injuries and illness are assessed among youth female elite athletes. Instead of solely focusing on time-loss injuries, our study included all substantial and non-substantial health problems (ie, injuries, mental problems and illnesses). METHODS: Sixty young elite Dutch female athletes (age: 16.6 years (SD: 2.3), weight: 58.3 kg (SD: 15.1), height: 154.1 cm (SD: 44.2)) participating in soccer (n=23), basketball (n=22) and gymnastic (n=15) talent development programmes were prospectively followed during one season (September 2014 to April 2015). To collect health problem data, all athletes completed the Oslo Sports Trauma Research Center Questionnaire on Health Problems every other week. Main outcome measures were average prevalence of injury and incidence density of injury. RESULTS: At any given time, 47.9% of the athletes reported an injury (95% CI 43.6% to 52.6%) and 9.1% reported an illness (95% CI 5.1 to 19.0). The average injury incidence density was 8.6 per 1000 hours of athlete exposure. The average number of self-reported injuries per athlete per season was significantly higher in soccer athletes (4.3±2.7) than in basketball athletes (2.6±2.0) (p=0.03) and not significantly higher than in the gymnastic squad. The knee and the ankle were two of the most common injury locations for all squads. Knee injuries in basketball and soccer and heel injuries in the gymnastic squad had the highest impact on sports participation. CONCLUSION: High prevalence of self-reported injuries among talented female athletes suggests that future efforts towards their prevention are warranted.

20.
Acta Physiol (Oxf) ; 219(3): 640-651, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-27273014

RESUMEN

AIM: Calcium channel blockers are widely used in cardiovascular diseases. Besides L-type channels, T- and P/Q-type calcium channels are involved in the contraction of human renal blood vessels. It was hypothesized that T- and P/Q-type channels are involved in the contraction of human brain and mammary blood vessels. METHODS: Internal mammary arteries from bypass surgery patients and cerebral arterioles from patients with brain tumours with and without hypertension were tested in a myograph and perfusion set-up. PCR and immunohistochemistry were performed on isolated blood vessels. RESULTS: The P/Q-type antagonist ω-agatoxin IVA (10-8  mol L-1 ) and the T-type calcium blocker mibefradil (10-7  mol L-1 ) inhibited KCl depolarization-induced contraction in mammary arteries from hypertensive patients with no effect on blood vessels from normotensive patients. ω-Agatoxin IVA decreased contraction in cerebral arterioles from hypertensive patients. L-type blocker nifedipine abolished the contraction in mammary arteries. PCR analysis showed expression of P/Q-type (Cav 2.1), T-type (Cav 3.1 and Cav 3.2) and L-type (Cav 1.2) calcium channels in mammary and cerebral arteries. Immunohistochemical labelling of mammary and cerebral arteries revealed the presence of Cav 2.1 in endothelial and smooth muscle cells. Cav 3.1 was also detected in mammary arteries. CONCLUSION: P/Q- and T-type Cav are present in human internal mammary arteries and in cerebral penetrating arterioles. P/Q- and T-type calcium channels are involved in the contraction of mammary arteries from hypertensive patients but not from normotensive patients. Furthermore, in cerebral arterioles P/Q-type channels importance was restricted to hypertensive patients might lead to that T- and P/Q-type channels could be a new target in hypertensive patients.


Asunto(s)
Canales de Calcio/metabolismo , Arterias Cerebrales/metabolismo , Hipertensión/metabolismo , Arterias Mamarias/metabolismo , Vasoconstricción/fisiología , Anciano , Bloqueadores de los Canales de Calcio/farmacología , Canales de Calcio/efectos de los fármacos , Arterias Cerebrales/efectos de los fármacos , Femenino , Humanos , Inmunohistoquímica , Masculino , Arterias Mamarias/efectos de los fármacos , Persona de Mediana Edad , Técnicas de Cultivo de Órganos , Técnicas de Placa-Clamp , Reacción en Cadena de la Polimerasa , Vasoconstricción/efectos de los fármacos
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