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1.
Eur Spine J ; 28(5): 1156-1179, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30879185

RESUMEN

PURPOSE: To determine the reliability and validity of self-reported questionnaires to measure pain and disability in adults with grades I-IV neck pain and its associated disorders (NAD). METHODS: We updated the systematic review of the 2000-2010 Bone and Joint Decade Task Force on Neck Pain and its Associated Disorders and systematically searched databases from 2005 to 2017. Independent reviewers screened and critically appraised studies using standardized tools. Evidence from low-risk-of-bias studies was synthesized according to best evidence synthesis principles. Validity studies were ranked according to the Sackett and Haynes classification. RESULTS: We screened 2823 articles, and 26 were eligible for critical appraisal; 18 were low risk of bias. Preliminary evidence suggests that the Neck Disability Index (original and short versions), Whiplash Disability Questionnaire, Neck Pain Driving Index, and ProFitMap-Neck may be valid and reliable to measure disability in patients with NAD. We found preliminary evidence for the validity and reliability of pain measurements including the Body Pain Diagram, Visual Analogue Scale, the Numeric Rating Scale and the Pain-DETECT Questionnaire. CONCLUSION: The evidence supporting the validity and reliability of instruments used to measure pain and disability is preliminary. Further validity studies are needed to confirm the clinical utility of self-reported questionnaires to assess pain and disability in patients with NAD. These slides can be retrieved under Electronic Supplementary Material.


Asunto(s)
Evaluación de la Discapacidad , Dolor de Cuello/complicaciones , Dimensión del Dolor , Humanos , Reproducibilidad de los Resultados , Autoinforme , Encuestas y Cuestionarios
2.
Spine J ; 23(7): 1028-1036, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-36958668

RESUMEN

BACKGROUND CONTEXT: Five out of 10 injured in a motor vehicle collision (MVC) will develop persistent pain and disability. It is unclear if prolonged symptoms are related to peritraumatic pain/disability, psychological distress, muscle fat, lower extremity weakness. PURPOSE: To test if widespread muscle fat infiltration (MFI) was (1) unique to those with poor recovery, (2) present in the peritraumatic stage, (3) related to known risk factors. STUDY DESIGN/SETTING: A cohort study, single-center academic hospital. PATIENT SAMPLES: A total of 97 men and women (age 18-65) presenting to an urban academic emergency medicine department following MVC, but not requiring inpatient hospitalization. PRIMARY OUTCOME MEASURE: Neck disability at 12-months. METHODS: Participants underwent magnetic resonance imaging (MRI) to quantify neck and lower extremity MFI, completed questionnaires on pain/disability and psychological distress (< 1-week, 2-weeks, 3-, and 12-months) and underwent maximum volitional torque testing of their lower extremities (2-weeks, 3-, and 12-months). Percentage score on the Neck Disability Index at 12-months was used for a model of (1) Recovered (0%-8%), (2) Mild (10%-28%), and (3) Moderate/Severe (≥ 30%). This model was adjusted for BMI and age. RESULTS: Significant differences for neck MFI were revealed, with the Recovered group having significantly lower neck MFI than the Mild and Moderate/Severe groups at all time points. The Mild group had significantly more leg MFI at 12-months (p=.02) than the Recovered group. There were no other significant differences at any other time point. Lower extremity torques revealed no group differences. The Traumatic Injury Distress Scale (TIDS) and MFI of the neck at 1-week postinjury significantly predicted NDI score at 12-months. CONCLUSIONS: Higher neck MFI and distress may represent a risk factor though it is unclear whether this is a pre-existing phenotype or result of the trauma. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02157038.


Asunto(s)
Lesiones por Latigazo Cervical , Femenino , Humanos , Lesiones por Latigazo Cervical/complicaciones , Lesiones por Latigazo Cervical/diagnóstico por imagen , Lesiones por Latigazo Cervical/patología , Estudios de Cohortes , Cuello , Dolor , Progresión de la Enfermedad , Vehículos a Motor
3.
Inj Prev ; 15(5): 334-40, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19805603

RESUMEN

There is growing recognition that different research approaches are necessary to understand the complex interaction between individual and social processes that contribute to risk-taking and injuries. Therefore, qualitative studies have an important role in injury prevention research. This article describes qualitative research in general and outlines some of the ways qualitative research can add to our understanding of injury. It also describes the role, format and methods of interviews (person-to-person and focus groups) commonly performed in qualitative studies, and proposes a novel approach to interviewing that has special relevance and value in injury research with indigenous populations. This methodology adapts focus group methods to be consistent with the goals and procedures of the traditional First Nations communities' Sharing Circles. This adaptation provides a culturally appropriate and sensitive method of developing a deep and broad understanding of indigenous participants' verbal descriptions of their feelings, their experiences and their modes of reasoning. After detailing of this adaptation of the Sharing Circle as a vibrant and vital interview and analysis method, the use of Sharing Circle interview methodology will be illustrated in a study investigating how an Alberta First Nations community experiences and deals with disproportionate levels of injuries arising from impaired driving, outlining important findings uncovered using this novel interviewing method. These findings have been informative to First Nations communities themselves, have informed policy makers provincially and nationally, and have instigated culturally appropriate intervention techniques for Canadian First Nations communities.


Asunto(s)
Actitud Frente a la Salud , Indígenas Norteamericanos/psicología , Entrevistas como Asunto/métodos , Investigación Cualitativa , Adolescente , Adulto , Alberta , Consumo de Bebidas Alcohólicas/etnología , Conducción de Automóvil/psicología , Comunicación , Características Culturales , Femenino , Grupos Focales , Humanos , Masculino , Asunción de Riesgos , Heridas y Lesiones/etnología , Heridas y Lesiones/etiología , Heridas y Lesiones/prevención & control , Adulto Joven
4.
Sci Adv ; 4(11): eaao6051, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-30456300

RESUMEN

The structural hierarchy exhibited by materials on more than one length scale can play a major part in determining bulk material properties. Understanding the hierarchical structure can lead to new materials with physical properties tailored for specific applications. We have used a combined experimental and phase-field modeling approach to explore such a hierarchical structure at nanoscale for enhanced coarsening resistance of ordered γ' precipitates in an experimental, multicomponent, high-refractory nickel-base superalloy. The hierarchical microstructure formed experimentally in this alloy is composed of a γ matrix with γ' precipitates that contain embedded, spherical γ precipitates, which do not directionally coarsen during high-temperature annealing but do delay coarsening of the larger γ' precipitates. Chemical mapping via atom probe tomography suggests that the supersaturation of Co, Ru, and Re in the γ' phase is the driving force for the phase separation, leading to the formation of this hierarchical microstructure. Representative phase-field modeling highlights the importance of larger γ' precipitates to promote stability of the embedded γ phase and to delay coarsening of the encompassing γ' precipitates. Our results suggest that the hierarchical material design has the potential to influence the high-temperature stability of precipitate strengthened metallic materials.

5.
Eur J Pain ; 21(2): 201-216, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27712027

RESUMEN

We conducted a systematic review of guidelines on the management of low back pain (LBP) to assess their methodological quality and guide care. We synthesized guidelines on the management of LBP published from 2005 to 2014 following best evidence synthesis principles. We searched MEDLINE, EMBASE, CINAHL, PsycINFO, Cochrane, DARE, National Health Services Economic Evaluation Database, Health Technology Assessment Database, Index to Chiropractic Literature and grey literature. Independent reviewers critically appraised eligible guidelines using AGREE II criteria. We screened 2504 citations; 13 guidelines were eligible for critical appraisal, and 10 had a low risk of bias. According to high-quality guidelines: (1) all patients with acute or chronic LBP should receive education, reassurance and instruction on self-management options; (2) patients with acute LBP should be encouraged to return to activity and may benefit from paracetamol, nonsteroidal anti-inflammatory drugs (NSAIDs), or spinal manipulation; (3) the management of chronic LBP may include exercise, paracetamol or NSAIDs, manual therapy, acupuncture, and multimodal rehabilitation (combined physical and psychological treatment); and (4) patients with lumbar disc herniation with radiculopathy may benefit from spinal manipulation. Ten guidelines were of high methodological quality, but updating and some methodological improvements are needed. Overall, most guidelines target nonspecific LBP and recommend education, staying active/exercise, manual therapy, and paracetamol or NSAIDs as first-line treatments. The recommendation to use paracetamol for acute LBP is challenged by recent evidence and needs to be revisited. SIGNIFICANCE: Most high-quality guidelines recommend education, staying active/exercise, manual therapy and paracetamol/NSAIDs as first-line treatments for LBP. Recommendation of paracetamol for acute LBP is challenged by recent evidence and needs updating.


Asunto(s)
Terapia por Acupuntura , Antiinflamatorios no Esteroideos/uso terapéutico , Terapia por Ejercicio/métodos , Dolor de la Región Lumbar/terapia , Manipulaciones Musculoesqueléticas/métodos , Humanos , Dolor de la Región Lumbar/tratamiento farmacológico , Ontario , Revisiones Sistemáticas como Asunto
6.
FEBS Lett ; 274(1-2): 178-80, 1990 Nov 12.
Artículo en Inglés | MEDLINE | ID: mdl-2174800

RESUMEN

The mechanism of the maize pyruvate, phosphate dikinase-catalyzed conversion of adenosine 5'-triphosphate, orthophosphate and pyruvate to adenosine 5'-monophosphate, inorganic pyrophosphate and phosphoenolpyruvate, respectively, was determined by using transient kinetic techniques. The data obtained demonstrate that catalysis in the maize pyruvate, phosphate dikinase active site involves initial transfer of the P beta P-unit from adenosine 5'-trisphosphate to the enzyme to form a pyrophosphorylenzyme intermediate, followed by sequential phosphoryl group transfer to orthophosphate (to form pyrophosphate and a phosphoenzyme intermediate) and pyruvate (to form phosphoenolpyruvate and free enzyme).


Asunto(s)
Piruvato Ortofosfato Diquinasa/metabolismo , Zea mays/enzimología , Cinética , Modelos Teóricos , Unión Proteica
7.
Health Psychol ; 19(4): 333-8, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10907651

RESUMEN

This study had 2 objectives: (a) to assess the psychometric properties of the Pain Management Inventory (PMI; G. K. Brown & P. M. Nicassio, 1987) with individuals in the general population with neck or low back pain, and (b) to assess the relationship between pain severity and coping. Data were taken from a mailed survey of a random sample of adults residing in Saskatchewan, Canada. Results validated the 2-factor structure of the PMI and provided evidence for the internal consistency of the coping subscales. Regression analyses revealed that passive coping was associated with being married, greater pain severity, depression, and poor health. Active coping was associated with female gender, higher education, less depression, good health, and frequent exercise. This study provides psychometric data to support the use of the PMI and information about factors associated with use of active and passive coping strategies in pain sufferers.


Asunto(s)
Adaptación Psicológica , Dolor de la Región Lumbar/psicología , Dolor de Cuello/psicología , Dimensión del Dolor/estadística & datos numéricos , Adulto , Anciano , Demografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Psicometría
8.
Spine (Phila Pa 1976) ; 23(17): 1860-6; discussion 1867, 1998 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-9762743

RESUMEN

STUDY DESIGN: Population-based, cross-sectional, mailed survey. OBJECTIVES: To determine the lifetime, 6-month period, and point prevalence of low back pain and its related disability among Saskatchewan adults and to investigate the presence and strength of selective response bias. SUMMARY OF BACKGROUND DATA: There have been many reports of the prevalence of low back pain in different populations, and the estimates vary widely depending on case definition. However, most studies fail to differentiate between trivial and disabling back pain, which raises the issue of the usefulness of these estimates. No studies have yet documented the prevalence of graded low back pain severity and its related disability in a North American, general, population-based survey. METHODS: The Saskatchewan Health and Back Pain Survey was mailed to a probability sample of 2184 Saskatchewan adults between 20 and 69 years of age. Fifty-five percent of the eligible population responded to the survey. Respondents were compared with nonrespondents, and the presence of selective response bias by back pain status was investigated by wave analysis. The point and lifetime prevalence of low back pain was determined by simple questions, and the 6-month period prevalence of low back pain was determined by the Chronic Pain Questionnaire. All estimates were age standardized to the Saskatchewan population. RESULTS: The authors estimate that at the time of the survey 28.4% (95% confidence interval, 25.6-31.1) of the Saskatchewan adult population were experiencing low back pain, and 84.1% (95% confidence interval, 81.9-86.3) had experienced it during their lifetime. Overall, 48.9% (95% confidence interval, 45.9-52.0) of the population had experienced low intensity/low-disability low back pain in the previous 6 months, 12.3% (95% confidence interval, 10.3-14.4) had experienced high-intensity/low-disability low back pain, and an additional 10.7% (95% confidence interval, 8.8-12.5) had experienced high-disability low back pain in the previous 6 months. There was little variation in the estimates over age groups, but women experienced more high-disability back pain than men. There was no evidence of selective response bias by low back pain status in the survey. CONCLUSION: Low-intensity/low-disability low back pain is a common problem in the general population. Approximately 11% of the adult population studied had been disabled by low back pain in the previous 6 months.


Asunto(s)
Dolor de la Región Lumbar/epidemiología , Dolor de la Región Lumbar/rehabilitación , Adulto , Distribución por Edad , Anciano , Recolección de Datos , Evaluación de la Discapacidad , Femenino , Humanos , Masculino , Maniquíes , Persona de Mediana Edad , Prevalencia , Saskatchewan/epidemiología , Distribución por Sexo
9.
Can J Public Health ; 91(6): 459-64, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11200740

RESUMEN

OBJECTIVES: To determine the one-week period prevalence of depressive symptomatology among Saskatchewan adults and to identify sociodemographic and health factors associated with depressive symptomatology. METHODS: The Saskatchewan Health and Back Pain Survey was mailed to an age-stratified random sample of adults. Of the 2,184 eligible subjects, 55% (n = 1131) responded to the survey. We report age-standardized prevalence estimates stratified by age, gender and spinal pain severity. Logistic regression was used to measure the presence and strength of association between various factors and depressive symptomatology. RESULTS: 22.2% (95% CI 19.6-24.9) of adults experienced depressive symptomatology during the previous week, with higher rates in younger adults, in females, and in those with disabling spinal pain. Depressive symptomatology was associated with age, income, smoking, health status, gastro-intestinal problems, headaches and spinal pain. CONCLUSIONS: Depressive symptomatology is common in the Saskatchewan adult population, and is related to age, pain severity and general health.


Asunto(s)
Depresión/epidemiología , Encuestas Epidemiológicas , Dolor de la Región Lumbar/clasificación , Adulto , Anciano , Enfermedad Crónica , Depresión/etiología , Depresión/fisiopatología , Femenino , Estado de Salud , Humanos , Modelos Logísticos , Dolor de la Región Lumbar/complicaciones , Masculino , Persona de Mediana Edad , Dimensión del Dolor , Servicios Postales , Prevalencia , Factores de Riesgo , Saskatchewan/epidemiología , Encuestas y Cuestionarios
10.
Disabil Rehabil ; 26(11): 649-54, 2004 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-15204503

RESUMEN

PURPOSE: In recent years, researchers have noted that catastrophizing predicts both self-reported and objective measures of disability in a variety of chronic pain conditions. The present study sought to examine this in a working-age amputee population experiencing phantom pain. METHOD: Participants completed a postal questionnaire incorporating measures of pain, disability and coping. A response rate of 62% resulted in 315 completed data sets being incorporated into the study. RESULTS: Utilizing the three subscales of the Sickness Impact Profile, catastrophizing uniquely predicted 11% of the variance in overall level of disability, 6% in physical disability and 13% in psychosocial disability after accounting for demographic, amputation and pain-related variables. CONCLUSION: The findings suggest that catastrophizing is a significant predictor of self-reported disability in an amputee population. This population have lifetime rehabilitation needs in that prostheses have to be remade on a regular basis. The service provided tends to focus on physical rehabilitation with the goal of providing amputees with limbs that most closely resemble the appearance and function of the intact limb. This study provides tentative support for development of an intervention that specifically targets catastrophizing.


Asunto(s)
Amputados/psicología , Miembro Fantasma/psicología , Adaptación Psicológica , Adulto , Amputados/rehabilitación , Femenino , Humanos , Masculino , Persona de Mediana Edad , Perfil de Impacto de Enfermedad , Encuestas y Cuestionarios
11.
Disabil Rehabil ; 24(9): 462-70, 2002 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-12097215

RESUMEN

PURPOSE: To examine amputees' use of health, social and voluntary services and to assess the perceived benefit of such use. Additionally, to examine the degree and type of changes made in occupational status in relation to both pain and prosthetic limb use following amputation. METHOD: A survey methodology was employed to examine the services used by amputees and their experiences of occupational change. A response rate of 62% resulted in 315 amputees completing the study. The study sample was drawn from patient records at three artificial limb and appliance centres in the central belt of Scotland. RESULTS: Overall the data suggest that few amputees make use of the available services for general amputation-related problems. Even fewer services were utilized for phantom limb pain or for other pain problems. Moreover, of those services that were used, very few were reported as being helpful. Amputation had severe consequences in terms of employment with 75% of the sample in employment prior to the amputation and only 43.5% remaining following amputation. Additionally, of those who did remain in employment there were a number of changes from pre- to post-amputation occupational classification. Employment status was related to the intensity of phantom limb pain, and daily prosthetic limb use with unemployed amputees reporting higher levels of pain and lower levels of prosthesis use. CONCLUSIONS: The study demonstrates the need for further research to determine whether the results obtained regarding occupational changes following amputation result pain, disability, amputees' attitudes towards themselves in relation to work, or to employers' attitudes and beliefs about their capabilities. Further research is also required to determine why so few amputees make use of available services and why, even when they are used, such services are not perceived as being helpful. Finally, there is a need to clarify the relationship between the extent of daily prostheses use, the experience of phantom limb pain and employment status.


Asunto(s)
Amputados , Empleo , Miembro Fantasma , Adulto , Amputados/psicología , Amputados/rehabilitación , Miembros Artificiales , Actitud Frente a la Salud , Femenino , Humanos , Masculino , Persona de Mediana Edad , Miembro Fantasma/prevención & control
12.
Mult Scler ; 13(8): 1038-45, 2007 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-17895295

RESUMEN

Baseline data from a population-based study examining the health-related quality of life (HRQL) of MS patients about to begin disease modifying therapy was used to determine the factors associated with the HRQL of Saskatchewan adults with relapsing-remitting MS. Participants completed a self-report questionnaire regarding demographic and socioeconomic status, fatigue, comorbid medical conditions, disability level (EDSS), number of attacks in past 6 months, illness intrusiveness (Illness Intrusiveness Ratings Scale), depression (Beck Depression Inventory), and HRQL (SF-36 Health Status Survey). Multiple linear regression models were used to identify the factors associated with the physical and mental health summary scores of the SF-36. We found poorer physical HRQL in those who are female; older; not working; have musculoskeletal or respiratory problems; greater fatigue, higher disability scores, and more MS attacks. High illness intrusiveness; digestive system problems; genitourinary problems; and headaches were associated with poorer mental HRQL. Interestingly, we found an interaction between sex and age in mental HRQL, with worse mental health in older men but better mental health in older women. These findings may assist health care providers in identifying patients who may be at risk for decline in their HRQL, permitting appropriate and timely interventions.


Asunto(s)
Fatiga/fisiopatología , Estado de Salud , Esclerosis Múltiple/fisiopatología , Esclerosis Múltiple/psicología , Calidad de Vida , Adulto , Anciano , Actitud Frente a la Salud , Depresión/epidemiología , Empleo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Saskatchewan , Índice de Severidad de la Enfermedad , Factores Socioeconómicos , Medicina Estatal
13.
Ann Rheum Dis ; 64(9): 1337-42, 2005 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-15731286

RESUMEN

OBJECTIVE: To describe the systemic nature of the illness reported after motor vehicle collisions using data from a large, population based cohort of individuals making an injury insurance claim. METHODS: All subjects who submitted a claim or were treated for whiplash injury following a motor vehicle collision in Saskatchewan, Canada during an 18 month period were examined. Demographics of claimants, collision related data, pre-collision health data, symptom prevalence, and scores on the short form 36 item general health survey (SF-36) were obtained on average within one month post-collision. RESULTS: Of 9006 potentially eligible claimants, 7462 (83%) met criteria for whiplash injury and provided information regarding demographics and injury related symptoms; 45% of these consented to complete the SF-36 at baseline. For most subjects, neck pain was only one of many diffuse and intense symptoms, including, often, low back pain. The range of symptoms, including fatigue, dizziness, paraesthesiae, headache, spinal pain, nausea, and jaw pain, could be interpreted as a systemic disorder. SF-36 scores showed low physical and mental functioning one month post-collision. CONCLUSIONS: What is commonly referred to as whiplash associated disorders (WAD) is best appreciated as a syndrome extending well beyond what can be labelled as a neck injury. More research is needed for a better understanding of the underlying mechanisms involved so that treatment can be directed at the broad spectrum of the illness rather than focusing on finding a focal neck injury.


Asunto(s)
Lesiones por Latigazo Cervical/epidemiología , Accidentes de Tránsito , Adulto , Estudios de Cohortes , Femenino , Cefalea/epidemiología , Cefalea/etiología , Indicadores de Salud , Humanos , Formulario de Reclamación de Seguro , Seguro por Accidentes , Dolor de la Región Lumbar/epidemiología , Dolor de la Región Lumbar/etiología , Masculino , Persona de Mediana Edad , Dolor de Cuello/epidemiología , Dolor de Cuello/etiología , Saskatchewan/epidemiología , Factores Socioeconómicos , Síndrome , Lesiones por Latigazo Cervical/complicaciones , Lesiones por Latigazo Cervical/diagnóstico
14.
Biochemistry ; 32(7): 1803-9, 1993 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-8382522

RESUMEN

The intermediacy of a pyrophosphorylenzyme (E-PP) and phosphorylenzyme (E-P) in the Clostridium symbiosum pyruvate phosphate dikinase catalyzed interconversion of adenosine 5'-triphosphate (ATP), orthophosphate (Pi), and pyruvate with adenosine 5'-monophosphate (AMP), inorganic pyrophosphate (PPi), and phosphoenolpyruvate (PEP) was examined using transient kinetic techniques. Single-turnover experiments with [gamma-32P]ATP or [14C]ATP and PPDK were carried out in the presence and absence of Pi to test for pyrophosphorylenzyme and AMP formation, respectively. Formation of the E-PP.AMP complex was found to be followed by Pi binding and the formation of the E-P.AMP.PPi complex. The level of pyrophosphorylenzyme accumulated during a single turnover was found to be dependent on the divalent metal cofactor used (Mn2+ > Co2+ > Mg2+). Single-turnover experiments with [32P]PEP and PPDK were carried out in the presence and absence of PPi and pyruvate to test for phosphorylenzyme formation in the reverse, ATP-forming direction of the reaction. Phosphorylenzyme formed from the reaction of the E.PEP complex was converted in the presence of AMP and PPi to free enzyme at a rate exceeding the steady-state turnover rate. The reaction sequence for pyruvate phosphate dikinase was determined to be [formula see text] 31P NMR analysis of the phosphorylenzyme in the native (-4.0 ppm) and denatured form (-3.9 ppm) revealed a 3-N-phosphohistidine residue. Complexation of Mg2+ resulted in a 0.3 ppm upfield shift of the phosphorus resonance from native phosphorylenzyme while Mn2+ complexation lead to extensive line broadening, indicative of metal cofactor binding in close vicinity to the phosphoryl group.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Piruvato Ortofosfato Diquinasa/metabolismo , Adenosina Monofosfato/metabolismo , Adenosina Trifosfato/metabolismo , Catálisis , Cationes Bivalentes , Clostridium/enzimología , Cobalto/farmacología , Escherichia coli/enzimología , Cinética , Magnesio/farmacología , Espectroscopía de Resonancia Magnética , Manganeso/farmacología , Fosfatos/metabolismo , Fosfoenolpiruvato/metabolismo , Desnaturalización Proteica , Piruvatos/metabolismo , Ácido Pirúvico , Proteínas Recombinantes/metabolismo
15.
Biochemistry ; 33(5): 1134-42, 1994 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-8110745

RESUMEN

Proteolysis of Clostridium symbiosum pyruvate phosphate dikinase (PPDK) in its free or phosphorylated state with subtilisin Carlsberg followed two different cleavage pathways. The major pathway involved initial cleavage of the holoenzyme (93 kDa) into a stable 25-kDa N-terminal fragment and transiently stable 67-kDa C-terminal fragment. The 67-kDa fragment was cleaved to generate a stable 35-kDa fragment and an unstable 30-kDa fragment (containing the catalytic histidine). Proteolytic cleavage via the minor pathway divided the holoenzyme into an unstable 37-kDa N-terminal piece (which was further cleaved to the stable 25-kDa fragment produced in the major pathway) and a transiently stable 55-kDa C-terminal fragment. The 55-kDa fragment was then cleaved to produce the stable 35-kDa fragment produced by the major pathway. The cleavage pattern of PPDK complexed with the ATP analog adenyl imidodiphosphate was identical to that of the free enzyme, only the rate of cleavage as slower. In contrast, proteolysis of the phosphorylenzyme-oxalate complex generated the 55-kDa fragment indicating that oxalate binding induces a change in protein conformation. Treatment of PPDK with [1-14C]bromopyruvate followed by proteolysis revealed selective radiolabeling of the stable 35-kDa fragment while similar experiments with [14C]2',3'-dialdehyde adenosine 5'-monophosphate resulted in selective radiolabeling of the stable 25-kDa fragment. These results were interpreted to suggest that PPDK contains several structural domains and that the catalytic histidine, the pyruvate binding site, and the ATP binding site may be located on different domains.


Asunto(s)
Piruvato Ortofosfato Diquinasa/metabolismo , Adenosina Trifosfato/metabolismo , Secuencia de Aminoácidos , Sitios de Unión , Catálisis , Clostridium/enzimología , Hidrólisis , Ligandos , Datos de Secuencia Molecular , Fosforilación , Conformación Proteica , Piruvatos/metabolismo , Ácido Pirúvico , Especificidad por Sustrato , Subtilisinas/metabolismo
16.
N Engl J Med ; 342(16): 1179-86, 2000 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-10770984

RESUMEN

BACKGROUND AND METHODS: The incidence and prognosis of whiplash injury from motor vehicle collisions may be related to eligibility for compensation for pain and suffering. On January 1, 1995, the tort-compensation system for traffic injuries, which included payments for pain and suffering, in Saskatchewan, Canada, was changed to a no-fault system, which did not include such payments. To determine whether this change was associated with a decrease in claims and improved recovery after whiplash injury, we studied a population-based cohort of persons who filed insurance claims for traffic injuries between July 1, 1994, and December 31, 1995. RESULTS: Of 9006 potentially eligible claimants, 7462 (83 percent) met our criteria for whiplash injury. The six-month cumulative incidence of claims was 417 per 100,000 persons in the last six months of the tort system, as compared with 302 and 296 per 100,000, respectively, in the first and second six-month periods of the no-fault system. The incidence of claims was higher for women than for men in each period; the incidence decreased by 43 percent for men and by 15 percent for women between the tort period and the two no-fault periods combined. The median time from the date of injury to the closure of a claim decreased from 433 days (95 percent confidence interval, 409 to 457) to 194 days (95 percent confidence interval, 182 to 206) and 203 days (95 percent confidence interval, 193 to 213), respectively. The intensity of neck pain, the level of physical functioning, and the presence or absence of depressive symptoms were strongly associated with the time to claim closure in both systems. CONCLUSIONS: The elimination of compensation for pain and suffering is associated with a decreased incidence and improved prognosis of whiplash injury.


Asunto(s)
Seguro por Accidentes/estadística & datos numéricos , Seguro de Responsabilidad Civil/estadística & datos numéricos , Dolor de Cuello/economía , Lesiones por Latigazo Cervical/economía , Accidentes de Tránsito/economía , Adulto , Femenino , Humanos , Incidencia , Formulario de Reclamación de Seguro/estadística & datos numéricos , Revisión de Utilización de Seguros/estadística & datos numéricos , Seguro por Accidentes/economía , Seguro por Accidentes/legislación & jurisprudencia , Masculino , Dolor de Cuello/etiología , Pronóstico , Saskatchewan , Factores de Tiempo , Lesiones por Latigazo Cervical/complicaciones , Lesiones por Latigazo Cervical/epidemiología
17.
J Virol ; 70(11): 7669-77, 1996 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8892887

RESUMEN

Vaccinia virus early transcription factor (VETF) is a heterodimeric protein that is packaged in virus particles for expression of early genes during the next round of infection. To investigate additional roles of VETF, we constructed a conditionally lethal recombinant vaccinia virus in which the D6R gene, encoding the 70-kDa subunit of VETF, is under stringent Escherichia coli lac operator control. When cells were infected with the recombinant virus in the absence of an inducer, synthesis of the 70-kDa protein was undetectable and the yield of infectious virus was severely reduced. Under these nonpermissive conditions, DNA replication and synthesis of viral proteins other than the one encoded by D6R occurred, suggesting that de novo synthesis of VETF is not required for expression of early or late genes during the virus growth cycle. Electron microscopy, however, revealed that immature virus particles and masses of electron-dense material accumulated in the absence of an inducer. We concluded that VETF has a direct role in virion morphogenesis or is required for expression of a novel subset of genes that have such a role.


Asunto(s)
Factores de Transcripción/metabolismo , Virus Vaccinia/fisiología , Proteínas Virales/metabolismo , Animales , Línea Celular , Chlorocebus aethiops , Clonación Molecular , ADN Viral/biosíntesis , Células HeLa , Humanos , Isopropil Tiogalactósido/farmacología , Operón Lac , Morfogénesis , Recombinación Genética , Factores de Transcripción/biosíntesis , Factores de Transcripción/genética , Virus Vaccinia/efectos de los fármacos , Virus Vaccinia/genética , Virus Vaccinia/ultraestructura , Proteínas Virales/biosíntesis , Proteínas Virales/genética , Virión/ultraestructura , Ensamble de Virus
18.
J Virol ; 72(1): 104-12, 1998 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9420205

RESUMEN

The vaccinia virus early transcription factor (VETF) is a DNA binding protein comprised of 70- and 82-kDa subunits encoded by the D6R and A8L genes, respectively. A previous investigation suggested a novel role for the 70-kDa subunit in the morphogenesis of vaccinia virus particles. The principal objectives of the present study were to determine if the 82-kDa subunit of VETF is also required for morphogenesis and, if so, whether the block occurs before or after the incorporation of the genome into the assembling virus particle. To address these and other questions, we constructed and characterized a conditionally lethal recombinant vaccinia virus in which the A8L gene is stringently repressed by the Escherichia coli lac operator system. The amount of 82-kDa protein synthesized could be regulated by the amount of inducer: from undetectable to higher than normal levels. Virus replication, as determined by plaque formation or virus yield upon synchronous infection, was dependent on inducer. Nevertheless, de novo synthesis of the 82-kDa subunit was not required for viral early, intermediate, and late gene expression or DNA replication. Overexpression of the A8L gene alone, produced by high concentrations of inducer, inhibited viral late protein synthesis, whereas overexpression of the D6R gene alone or both VETF genes simultaneously had little inhibitory effect. Laser confocal fluorescence and quantitative electron microscopic analyses revealed that immature and DNA-containing intermediate stage particles accumulated in the absence of inducer, indicating that the A8L protein has a role in morphogenesis of the core and subsequent events.


Asunto(s)
Proteínas de Unión al ADN/genética , Genes Virales , Factores de Transcripción/genética , Virus Vaccinia/crecimiento & desarrollo , Virus Vaccinia/genética , Proteínas Virales/genética , Animales , Secuencia de Bases , Línea Celular , Cartilla de ADN/genética , ADN Viral/genética , ADN Viral/metabolismo , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/fisiología , Escherichia coli/genética , Regulación Viral de la Expresión Génica , Células HeLa , Humanos , Isopropil Tiogalactósido/farmacología , Operón Lac , Microscopía Confocal , Microscopía Electrónica , Peso Molecular , Mutación , Conformación Proteica , Recombinación Genética , Factores de Transcripción/química , Factores de Transcripción/fisiología , Virus Vaccinia/fisiología , Proteínas Virales/química , Proteínas Virales/fisiología
19.
Biochemistry ; 29(48): 10757-65, 1990 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-2176881

RESUMEN

In this paper we report the amino acid sequence of pyruvate phosphate dikinase (PPDK) from Bacteroides symbiosus as determined from the nucleotide sequence of the PPDK gene. Comparison of the B. symbiosus PPDK amino acid sequence with that of the maize PPDK [Matsuoka, M., Ozeki, Y., Yamamoto, N., Hirano, H., Kamo-Murakami, Y., & Tanaka, Y. (1988) J. Biol. Chem. 263, 11080] revealed long stretches of homologous sequence (greater than 70% identity), which contributed to an overall sequence identity of 53%. The circular dichrosim spectra, hydropathy profiles, and calculated secondary structural elements of the two dikinases suggest that they may have very similar tertiary structures as well. A comparison made between the amino acid sequence of the maize and B. symbiosus dikinase with other known protein sequences revealed homology, concentrated in three stretches of sequences, to a mechanistically related enzyme, enzyme I of the Escherichia coli PEP: sugar phosphotransferase system [Saffen, D. W., Presper, K. A., Doering, T. L., Roseman, S. (1987) J. Biol. Chem. 262, 16241]. It is proposed that (i) these three stretches of sequence constitute the site for PEP binding and catalysis and a possible site for the regulation of enzymatic activity and (ii) the conserved sequences exist in a third mechanistically related enzyme, PEP synthase.


Asunto(s)
Bacteroides/enzimología , Plantas/enzimología , Piruvato Ortofosfato Diquinasa/genética , Secuencia de Aminoácidos , Secuencia de Bases , Sitios de Unión , Catálisis , Dicroismo Circular , Clonación Molecular , Enzimas de Restricción del ADN , ADN Bacteriano/genética , Escherichia coli/genética , Datos de Secuencia Molecular , Fragmentos de Péptidos/química , Plásmidos , Conformación Proteica , Piruvato Ortofosfato Diquinasa/química , Homología de Secuencia de Ácido Nucleico , Zea mays
20.
Proc Natl Acad Sci U S A ; 93(7): 2652-7, 1996 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-8610096

RESUMEN

The crystal structure of pyruvate phosphate dikinase, a histidyl multiphosphotransfer enzyme that synthesizes adenosine triphosphate, reveals a three-domain molecule in which the phosphohistidine domain is flanked by the nucleotide and the phosphoenolpyruvate/pyruvate domains, with the two substrate binding sites approximately 45 angstroms apart. The modes of substrate binding have been deduced by analogy to D-Ala-D-Ala ligase and to pyruvate kinase. Coupling between the two remote active sites is facilitated by two conformational states of the phosphohistidine domain. While the crystal structure represents the state of interaction with the nucleotide, the second state is achieved by swiveling around two flexible peptide linkers. This dramatic conformational transition brings the phosphocarrier residue in close proximity to phosphoenolpyruvate/pyruvate. The swiveling-domain paradigm provides an effective mechanism for communication in complex multidomain/multiactive site proteins.


Asunto(s)
Pliegue de Proteína , Estructura Secundaria de Proteína , Piruvato Ortofosfato Diquinasa/química , Piruvato Ortofosfato Diquinasa/metabolismo , Secuencia de Aminoácidos , Sitios de Unión , Clostridium/enzimología , Cristalografía por Rayos X , Escherichia coli , Sustancias Macromoleculares , Modelos Moleculares , Modelos Estructurales , Datos de Secuencia Molecular , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Programas Informáticos
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