RESUMEN
BACKGROUND: Meta-analyses have reported associations between perseverative cognition (both worry and brooding) and increased engagement in health-risk behaviors, poorer sleep, and poorer physiological health outcomes. METHOD: Using a daily diary design, this study investigated the within- and between-person relationships between state and trait perseverative cognition and health behaviors (eating behavior, physical activity, alcohol consumption, and sleep) both cross-sectionally and prospectively. Participants (n = 273, 93% students, Mage = 20.2, SD = 4.11, 93% female) completed morning and evening diaries across 7 consecutive days. RESULTS: Multilevel modeling analyses revealed that, cross-sectionally, higher levels of state worry were associated with more time spent sitting and higher levels of state brooding predicted less daily walking. CONCLUSION: Worry and brooding may represent useful intervention targets for improving inactivity and walking levels, respectively.
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Ansiedad , Conductas Relacionadas con la Salud , Cognición , Femenino , Humanos , Masculino , Sueño , Encuestas y CuestionariosRESUMEN
Associations have been found between perseverative cognition (PC: worry and rumination) and somatic markers of ill-health. Further studies have reported associations between sleep and both PC and poorer health. As such, sleep disturbance may represent a pathway between PC and ill-health. Therefore, studies assessing the relationship between PC and sleep in non-clinical populations were synthesised. Meta-analyses (k = 55) revealed small- to medium-sized associations between higher PC and poorer sleep quality (SQ, r = -0.28), shorter total sleep time (TST, r = -0.15) and longer sleep onset latency (SOL, r = -0.16). Variations included associations between SQ and rumination (r = -.33) and worry (r = -.23). Associations were stronger in studies measuring SQ via self-report rather than actigraphy, and where SOL and TST outcomes were cross-sectional. Associations with SOL were stronger when outcomes were from non-diary studies and when trait, rather than state PC, was measured, but weaker where studies incorporated more measures of PC. Effect sizes were generally larger where studies were higher quality and being female may act as a protective factor between PC and longer SOL. Therefore, there is a consistent association between PC and sleep which may partially explain the link between PC and ill-health.
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Ansiedad/fisiopatología , Rumiación Cognitiva/fisiología , Trastornos del Sueño-Vigilia/psicología , Sueño/fisiología , Estrés Psicológico/fisiopatología , Ansiedad/psicología , Humanos , Estrés Psicológico/psicologíaRESUMEN
Two leading theories within the field of suicide prevention are the interpersonal psychological theory of suicidal behaviour (IPT) and the integrated motivational-volitional (IMV) model. The IPT posits that suicidal thoughts emerge from high levels of perceived burdensomeness and thwarted belongingness. The IMV model is a multivariate framework that conceptualizes defeat and entrapment as key drivers of suicide ideation. We applied network analysis to cross-sectional data collected as part of the Scottish Wellbeing Study, in which a nationally representative sample of 3508 young adults (18-34 years) completed a battery of psychological measures. Network analysis can help us to understand how the different theoretical components interact and how they relate to suicide ideation. Within a network that included only the core factors from both models, internal entrapment and perceived burdensomeness were most strongly related to suicide ideation. The core constructs defeat, external entrapment and thwarted belonginess were mainly related to other factors than suicide ideation. Within the network of all available psychological factors, 12 of the 20 factors were uniquely related to suicide ideation, with perceived burdensomeness, internal entrapment, depressive symptoms and history of suicide ideation explaining the most variance. None of the factors was isolated, and we identified four larger clusters: mental wellbeing, interpersonal needs, personality, and suicide-related factors. Overall, the results suggest that relationships between suicide ideation and psychological risk factors are complex, with some factors contributing direct risk, and others having indirect impact.
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Depresión/psicología , Relaciones Interpersonales , Motivación , Distancia Psicológica , Estrés Psicológico/psicología , Ideación Suicida , Intento de Suicidio/psicología , Adolescente , Adulto , Femenino , Humanos , Masculino , Teoría Psicológica , Factores de Riesgo , Escocia , Volición , Adulto JovenRESUMEN
This cohort study investigated the influence of psychological factors, including perception of illness, anxiety and depression on recovery and functional outcome after total knee replacement surgery. A total of 100 patients (55 male; 45 female) with a mean age of 71 (42 to 92) who underwent a primary total knee replacement for osteoarthritis were recruited into this study. In all 97 participants completed the six week and 87 the one year follow-up questionnaires. Pre-operatively patients completed the revised Illness Perception Questionnaire, Hospital Anxiety and Depression Scale and Recovery Locus of Control Scale. Function was assessed pre-operatively, at six weeks and one year using Oxford Knee Score (OKS) and the goniometer-measured range of movement (ROM). The results showed that pre-operative function had the biggest impact on post-operative outcome for ROM and OKS. In addition questionnaire variables and depression had an impact on the OKS at six weeks. Depression and anxiety were also associated with a higher (worse) knee score at one year but did not influence the ROM at either six weeks or one year. Recovery from total knee replacement can be difficult to predict. This study has identified psychological factors that play an important role in recovery from surgery and functional outcome. These should be taken into account when considering patients for total knee replacement.
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Artroplastia de Reemplazo de Rodilla/psicología , Conducta de Enfermedad , Osteoartritis de la Rodilla/cirugía , Percepción/fisiología , Rango del Movimiento Articular/fisiología , Recuperación de la Función , Estrés Psicológico/fisiopatología , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Osteoartritis de la Rodilla/psicología , Periodo Posoperatorio , Pronóstico , Estudios Prospectivos , Estrés Psicológico/etiología , Encuestas y CuestionariosRESUMEN
AIMS: Internationally, surgical training is facing the challenge of balancing research and clinical experience in the context of reduced working hours. This study aimed to investigate trainees and trainers' views on surgeons participating in full-time research during surgical training. METHODS: An anonymous voluntary survey was conducted of surgical trainers and trainees in two training systems. To examine surgeons' views across two different training schemes, surgeons were surveyed in Ireland (Royal College of Surgeons in Ireland) and in a Canadian centre (University of Toronto) between January 2009 and September 2010 (n = 397 respondents). RESULTS: The majority of respondents felt that time spent in research by trainees was important for surgery as a specialty, while 65 % felt that research was important for surgical trainees (trainers 79 %, trainees 60 %, p = 0.001). A higher proportion of Canadian surgeons reported that they enjoyed their time spent in research, compared to Irish surgeons (84 vs. 66 %, p = 0.05). Financial worries and loss of clinical time were common demotivating factors. Full-time research was more popular than part-time options to obtain a post-graduate degree. CONCLUSIONS: Most agree that research remains an important component of surgical training. However, there are significant differences in opinion among surgeons in different countries on the precise role and structure of research in surgical training.
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Actitud del Personal de Salud , Investigación Biomédica/educación , Especialidades Quirúrgicas/educación , Canadá , Recolección de Datos , Educación de Postgrado en Medicina , Irlanda , MédicosRESUMEN
The role of thyroid hormones in the control of erectile functioning has been only superficially investigated. The aim of the present study was to investigate the association between thyroid and erectile function in two different cohorts of subjects. The first one derives from the European Male Ageing Study (EMAS study), a multicentre survey performed on a sample of 3369 community-dwelling men aged 40-79 years (mean 60 ± 11 years). The second cohort is a consecutive series of 3203 heterosexual male patients (mean age 51.8 ± 13.0 years) attending our Andrology and Sexual Medicine Outpatient Clinic for sexual dysfunction at the University of Florence (UNIFI study). In the EMAS study all subjects were tested for thyroid-stimulating hormone (TSH) and free thyroxine (FT4). Similarly, TSH levels were checked in all patients in the UNIFI study, while FT4 only when TSH resulted outside the reference range. Overt primary hyperthyroidism (reduced TSH and elevated FT4, according to the reference range) was found in 0.3 and 0.2% of EMAS and UNIFI study respectively. In both study cohorts, suppressed TSH levels were associated with erectile dysfunction (ED). Overt hyperthyroidism was associated with an increased risk of severe erectile dysfunction (ED, hazard ratio = 14 and 16 in the EMAS and UNIFI study, respectively; both p < 0.05), after adjusting for confounding factors. These associations were confirmed in nested case-control analyses, comparing subjects with overt hyperthyroidism to age, BMI, smoking status and testosterone-matched controls. Conversely, no association between primary hypothyroidism and ED was observed. In conclusion, erectile function should be evaluated in all individuals with hyperthyroidism. Conversely, assessment of thyroid function cannot be recommended as routine practice in all ED patients.
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Disfunción Eréctil/etiología , Hipertiroidismo/complicaciones , Tirotropina/sangre , Tiroxina/sangre , Adulto , Anciano , Estudios de Casos y Controles , Estudios de Cohortes , Estudios Transversales , Humanos , Hipotiroidismo/complicaciones , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Fumar/efectos adversosRESUMEN
INTRODUCTION: Small bowel obstruction secondary to intussusception is a rare but important consequence of Roux-en-Y gastric bypass (RYGB). CASE REPORT: A 37-year old female presented to the emergency department with abdominal pain. She had undergone RYGB 5-years previously for obesity. CT revealed a retrograde jejuno-jejunal intussusception. The intussusceptum was the common jejunal channel and the intussuscepiens was the jejunojejunostomy resulting in obstruction of both the alimentary and biliary limbs. The patient underwent laparotomy, small bowel resection and refashioning of the jejunojejunal anastamosis. CONCLUSION: We report this case as it highlights both how a delay in diagnosis can occur and the importance of including this complication early in the differential diagnoses of any patient presenting with acute or chronic abdominal pain with a history of bariatric surgery. Retrograde intussusception is more common than previously thought and the incidence may increase as bariatric surgery is performed more frequently worldwide.
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Derivación Gástrica/efectos adversos , Intususcepción/etiología , Enfermedades del Yeyuno/etiología , Adulto , Femenino , Humanos , Intususcepción/cirugía , Enfermedades del Yeyuno/cirugía , Obesidad Mórbida/cirugíaRESUMEN
BACKGROUND: Patients undergoing major vascular surgery (MVS) require extensive anaesthetic assessment. This can require extended pre-operative stays. AIMS: We investigated whether a newly established anaesthetic pre-operative assessment clinic (PAC) would reduce the pre-operative inpatient stay, avoid unnecessary investigations and facilitate day before surgery (DBS) admissions for patients undergoing MVS. PATIENT AND METHODS: One year following and preceding the establishment of the PAC the records of patients undergoing open or endovascular aortic aneurysm repair, carotid endarterectomy and infra-inguinal bypass were reviewed to measure pre-operative length of stay (LoS). RESULTS: Pre-operative LoS was significantly reduced in the study period (1.85 vs. 4.2 days, respectively, P < 0.0001). Only 12 out of 61 patients in 2007 were admitted on the DBS and this increased to 33 out of 63 patients (P = 0.0002). No procedure was cancelled for medical reasons. CONCLUSION: The PAC has facilitated accurate outpatient anaesthetic assessment for patients requiring MVS. The pre-operative in-patient stay has been significantly reduced.
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Anestesiología/organización & administración , Tiempo de Internación , Servicio Ambulatorio en Hospital/organización & administración , Procedimientos Quirúrgicos Vasculares , Aneurisma de la Aorta/cirugía , Endarterectomía Carotidea , Hospitales Urbanos/organización & administración , Humanos , Irlanda , Cuidados Preoperatorios/métodos , Derivación y Consulta/organización & administraciónRESUMEN
Evidence from clinic-based studies suggests that the fibromyalgia syndrome (FMS) is associated with impairment in cognitive function though the mechanism is unclear. The aim of this analysis was to determine whether there is a similar association between chronic widespread pain (CWP), a cardinal feature of FMS, and impaired cognition in a community setting. Men (n=3369, 40-79 years) were recruited from population registers in eight centres for participation in the European Male Ageing Study (EMAS). The subjects completed a pain questionnaire and pain manikin, with the presence of CWP defined using the American College of Rheumatology criteria. The cognitive functions measured were visuospatial-constructional ability and visual memory (Rey-Osterrieth Complex Figure [ROCF]); visual recognition (Camden Topographical Recognition Memory test [CTRM]); and psychomotor processing speed (Digit-Symbol Substitution test [DSST]). We restricted our analysis to those subjects reporting pain that satisfied the criteria for CWP and those who were pain free. Of these 1539 men [mean (SD) age 60 (11) years], 266 had CWP. All cognitive test scores declined cross-sectionally with age (P<0.05). In age-adjusted linear regressions men with CWP had a lower DSST score (ß=-2.4, P<0.001) compared to pain-free subjects. After adjustment for lifestyle and health factors the association between pain status and the DSST score was attenuated but remained significant (ß=-1.02, P=0.04). There was no association between CWP and the ROCF-copy, ROCF-recall or CTRM scores. CWP is associated with slower psychomotor processing speed among community-dwelling European men. Prospective studies are required to confirm this observation and explore possible mechanisms for the association.
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Envejecimiento , Trastornos del Conocimiento/fisiopatología , Dolor/fisiopatología , Dolor/psicología , Adulto , Anciano , Enfermedad Crónica , Trastornos del Conocimiento/epidemiología , Estudios de Cohortes , Europa (Continente)/epidemiología , Humanos , Aprendizaje/fisiología , Estilo de Vida , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Dolor/epidemiología , Estimulación Luminosa/métodos , Desempeño Psicomotor/fisiología , Tiempo de Reacción , Valores de Referencia , Características de la Residencia , Estadísticas no Paramétricas , Encuestas y Cuestionarios , Percepción Visual/fisiología , Población BlancaRESUMEN
OBJECTIVES: The cortisol awakening rise (CAR) is defined as cortisol secretory activity in the first 45-60 min immediately post-awakening. It has been suggested that psychological factors may disrupt the normal awakening rise. Recent research has shown that psychological stress may influence the magnitude of the CAR, however the findings have been mixed. This study examined the impact of stress on the CAR and the diurnal mean in a sample of middle-aged women. METHOD: One hundred and eighteen healthy female participants who reported experiencing high or low stress were recruited. Salivary cortisol levels were measured immediately upon awakening (at 0, 15, 30, and 45 min) and at 3, 6, 9 and 12 h on two consecutive days. A number of metabolic and inflammatory biomarkers were also assessed together with measures of mood disturbance and health behaviour. RESULTS: The magnitude of the CAR, assessed by the area under the response curve (AURC) estimate, was significantly lower in the high stress group compared to the low stress group indicating that participants who experienced high stress secreted lower levels of cortisol. The effect was largely accounted for by differences 30 min after waking. The diurnal mean was also lower for the high stress group. Although participants in the high stress group had a slightly worse inflammatory profile, only low-density lipoprotein levels were found to be significantly higher, compared to the low stress group. Lifestyle indicators and mood were also found to be significantly poorer in the high stress group. CONCLUSIONS: The results suggest that psychological stress may be associated with a smaller cortisol awakening rise, a lower diurnal mean, poor lifestyle choices and high levels of psychological distress. These findings may have broader implications for future health risk and for an individual's ability to cope with imminent daily stressors and demands.
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Hidrocortisona/metabolismo , Mediadores de Inflamación/sangre , Estrés Psicológico/metabolismo , Adulto , Afecto/fisiología , Biomarcadores/metabolismo , Proteína C-Reactiva/metabolismo , Colesterol/sangre , Ritmo Circadiano/fisiología , Dinoprost/análogos & derivados , Dinoprost/sangre , Femenino , Conductas Relacionadas con la Salud , Humanos , Interleucina-6/sangre , Persona de Mediana Edad , Factores de Riesgo , Saliva/metabolismo , Factores de Tiempo , Triglicéridos/sangre , Vigilia/fisiologíaRESUMEN
This study investigated the effect of transdermal T and oral desogestrel on the reproductive axis of healthy men. Twenty-three men were randomized to 1 of 3 treatment groups and received a daily transdermal T patch plus oral desogestrel at a dose of 75, 150, or 300 microg/d for 24 wk. Baseline blood and semen samples were obtained and then every 4 wk thereafter for 32 wk. The outcome measures were sperm density and plasma levels of FSH, LH, total and free T. The results show a dose-dependent suppression of spermatogenesis and gonadotropins. Seven of the 17 subjects became azoospermic. Desogestrel (300 microg daily) in combination with 5 mg daily transdermal T was the most effective (57% azoospermic), whereas a dose of 75 microg was ineffective (0% azoospermic). Total and free plasma T were reduced by approximately 30%. High density lipoprotein cholesterol was significantly reduced. No serious side-effects were encountered. We conclude that daily self-administered desogestrel with transdermal T is capable of suppressing the male reproductive axis, although the efficacy was less marked and less consistent than injectable regimens. The lower efficacy is likely to be due to failure of the transdermal T system to maintain circulating T levels consistently in the required range.
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Anticonceptivos Masculinos/farmacología , Anticonceptivos Sintéticos Orales/farmacología , Desogestrel/farmacología , Espermatogénesis/efectos de los fármacos , Testosterona/uso terapéutico , Administración Cutánea , Adulto , Anticonceptivos Masculinos/administración & dosificación , Anticonceptivos Masculinos/efectos adversos , Anticonceptivos Sintéticos Orales/administración & dosificación , Anticonceptivos Sintéticos Orales/efectos adversos , Desogestrel/administración & dosificación , Desogestrel/efectos adversos , Método Doble Ciego , Femenino , Hormona Folículo Estimulante/sangre , Hormonas/sangre , Humanos , Hormona Luteinizante/sangre , Masculino , Semen/citología , Recuento de Espermatozoides , Testosterona/administración & dosificación , Testosterona/efectos adversosRESUMEN
OBJECTIVES: The effect of testosterone (T) on sexual function in men is well established. However, less is known about its effects on cognitive function. The aim of this study is to investigate the relationship between T levels and sex-typed cognitive abilities in both eugonadal and hypogonadal men. DESIGN: A single-blind placebo-controlled design was employed in this study. METHODS: Thirty healthy eugonadal men and seven hypogonadal men participated in the study. Eugonadal men were randomised into one of two treatment regimens: (1) active group--receiving 200 mg of T enanthate i.m. weekly for 8 weeks (raising T levels into the supraphysiological range) or (2) placebo group--receiving 200 mg of sodium chloride i.m. weekly for 8 weeks. The hypogonadal group received the physiological replacement dose of 200 mg T enanthate i.m. bi-weekly for 8 weeks. All groups underwent a battery of neuropsychological tests and had circulating T measured at baseline, and at weeks 4 and 8 during treatment. RESULTS: A significant time by group interaction effect was found in the measure of spatial ability (i.e., block design test) indicating that the active group's performance declined significantly at week 4, compared to placebo group (F(4,64)=3.78, P<0.01). Conversely, the active group performed significantly better than the placebo group in the measure of verbal fluency (i.e., the Controlled Oral Word Association Test) at week 4 (F(4,64)=2.54, P<0.05). No significant changes were found on any of the other tests. Generally, the hypogonadal group performed less well than the eugonadal groups on all tests. CONCLUSIONS: These results offer support to the notion that increased T has a differential effect on cognitive function, inhibiting spatial abilities while improving verbal fluency in eugonadal men.
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Cognición/efectos de los fármacos , Hormonas Esteroides Gonadales/farmacología , Hipogonadismo/tratamiento farmacológico , Hipogonadismo/psicología , Testosterona/análogos & derivados , Testosterona/farmacología , Adulto , Análisis de Varianza , Hormonas Esteroides Gonadales/administración & dosificación , Humanos , Inyecciones Intravenosas , Masculino , Pruebas Neuropsicológicas , Método Simple Ciego , Percepción Espacial , Testosterona/administración & dosificación , Testosterona/sangre , Aprendizaje Verbal/efectos de los fármacosRESUMEN
BACKGROUND: Occupational stress has been implicated as an independent risk factor in the aetiology of coronary heart disease and increased hypertensive risk in a number of occupations. Despite the large number of studies into GP stress, none have employed an objective physiological stress correlate. OBJECTIVES: We conducted an exploratory study to investigate whether self-reported occupational stress levels as measured by the General Practitioner Stress Index (GPSI) were predictive of ambulatory blood pressure (ABP) using a Spacelabs 90207 in a sample of British GPs. METHOD: Twenty-seven GPs (17 males, 10 females) participated in the study. Each GP wore an ABP monitor on a normal workday and non-workday. All GPs completed the GPSI before returning the ABP monitors. Demographic data were also collected. RESULTS: Stress associated with 'interpersonal and organizational change' emerged from the stepwise multiple regression analysis as the only significant predictor of ABP, explaining 21% of the variance in workday systolic blood pressure, 26% during the workday evening and 19% during the non-workday. For diastolic blood pressure, the same variable explained 29% of the variability during the workday and 17% during the non-workday. No significant gender differences were found on any of the ABP measures. CONCLUSIONS: For the first time in GP stress research, our findings established that higher levels of self-reported occupational stress are predictive of greater ABP in British GPs. More detailed psychophysiological research and stress management interventions are required to isolate the effects of occupational stress in British GPs.
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Presión Sanguínea/fisiología , Salud Laboral , Médicos de Familia/psicología , Estrés Psicológico/complicaciones , Adulto , Monitoreo Ambulatorio de la Presión Arterial , Femenino , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Innovación Organizacional , Estrés Psicológico/fisiopatología , Encuestas y CuestionariosRESUMEN
The analysis of suicide notes is an integral part of understanding suicidal behaviour. To this end, Leenaars (1996, 1992) has developed the Thematic Guide to Suicide Prediction (TGSP) for profiling the psychological correlates of suicide. The utility of this tool in suicide prevention, however, is not known. This study applied the TGSP to suicide notes (n = 45), interpreted in the light of coroner's inquest papers, drawn from a Northern Irish population. The results yielded support for the existence of psychological suicidal correlates. Moreover, qualitative differences between depressed and not depressed notewriters and those with and without a previous suicidal attempt were identified. For example, depressed suicides were more likely to communicate difficulties in developing attachments, or to exhibit cognitive constriction than nondepressed notewriters. Analysis of age differences was limited because of the paucity of suicide notes (in this sample, written by individuals aged 65 years or older). This research has further helped to identify psychological differences that should be beneficial in the prevention of suicide. Such differences should be integrated into existing risk assessment schedules. It is also argued that the analysis of suicide notes should form one strand in an integrated research framework.
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Comunicación , Suicidio/psicología , Adolescente , Adulto , Trastorno Depresivo/psicología , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
The UV-visible absorption and magnetic circular dichroism (MCD) spectra of the ferric, ferrous, CO-ligated forms and kinetic photolysis intermediates of the tetraheme electron-transfer protein cytochrome c3 (Cc3) are reported. Consistent with bis-histidinyl axial coordination of the hemes in this Class III c-type cytochrome, the Soret and visible region MCD spectra of ferric and ferrous Cc3 are very similar to those of other bis-histidine axially coordinated hemeproteins such as cytochrome b5. The MCD spectra indicate low spin state for both the ferric (S = 1/2) and ferrous (S = 0) oxidation states. CO replaces histidine as the axial sixth ligand at each heme site, forming a low-spin complex with an MCD spectrum similar to that of myoglobin-CO. Photodissociation of Cc3-CO (observed photolysis yield = 30%) produces a transient five-coordinate, high-spin (S = 2) species with an MCD spectrum similar to deoxymyoglobin. The recombination kinetics of CO with heme Fe are complex and appear to involve at least five first-order or pseudo first-order rate processes, corresponding to time constants of 5.7 microseconds, 62 microseconds, 425 microseconds, 2.9 ms, and a time constant greater than 1 s. The observed rate constants were insensitive to variation of the actinic photon flux, suggesting noncooperative heme-CO rebinding. The growing in of an MCD signal characteristic of bis-histidine axial ligation within tens of microseconds after photodissociation shows that, although heme-CO binding is thermodynamically favored at 1 atm CO, binding of histidine to the sixth axial site competes kinetically with CO rebinding.
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Grupo Citocromo c/química , Desulfovibrio vulgaris/química , Fenómenos Biofísicos , Biofisica , Monóxido de Carbono/química , Dicroismo Circular , Grupo Citocromo c/efectos de la radiación , Hemo/química , Cinética , Magnetismo , Fotólisis , Espectrofotometría , Espectrofotometría UltravioletaRESUMEN
Near-UV-vis magnetic and natural circular dichroism (MCD and CD) spectra of oxidized, reduced, and carbonmonoxy-complexed cytochrome ba3, a terminal oxidase from the bacterium Thermus thermophilus, and nanosecond time-resolved MCD (TRMCD) and CD (TRCD) spectra of the unligated species formed after photodissociation of the CO complex are presented. The spectral contributions of individual cytochromes b and a3 to the Soret region MCD are identified. TRMCD spectroscopy is used to follow the spin state change (S = 0 to S = 2) in cytochrome a3(2+) following photodissociation of the CO complex. There is prompt appearance of the high-spin state after photolysis, as found previously in mammalian cytochrome oxidase [Goldbeck, R. A., Dawes, T. D., Einarsdóttir, O., Woodruff, W. H., & Kliger, D. S. (1991) Biophys. J. 60, 125-134]. Peak shifts of 1-10 nm appear in the TRMCD, TRCD, and time-resolved UV-vis absorption spectra of the photolyzed enzyme throughout its observable lifetime, indicating that the photolyzed enzyme does not relax to its equilibrium deliganded form before recombination with CO occurs hundreds of milliseconds later. Direct heme-heme interaction is not found in cytochrome ba3, but red-shifts in the MCD and absorption spectra of both cytochromes b and (photolyzed) a3 are correlated with a CO-liganded form of the protein. The long time (tau approximately greater than 1 s) needed for relaxation of the cytochrome b and a3 peaks to their static positions suggests that CO binding to a3 induces a global conformational change in the protein that weakly perturbs the MCD and absorption spectra of b and photolyzed a3. Fea3 binds CO more weakly in cytochrome ba3 than in cytochrome aa3. The MCD spectrum of reduced enzyme solution placed under 1 atm of CO contains a peak at 446 nm that shows approximately 30% of total cytochrome a3 remains pentacoordinate, high-spin.