Incidence, Mechanisms, and Characteristics of Injuries in Pole Dancers: A Prospective Cohort Study.

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.

Tamoxifen-independent Cre-activity in SMMHC-CreER T2 mice.

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.

Basement membrane collagen IV deficiency promotes abdominal aortic aneurysm formation.

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.

Dance Movement Therapy for Clients With a Personality Disorder: A Systematic Review and Thematic Synthesis.

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.

Do hip and groin muscle strength and symptoms change throughout a football season in professional male football players? A prospective cohort study with repeated measures.

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.

Characteristics and Extent of Mental Health Issues in Contemporary Dance Students.

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.

High prevalence of self-reported injuries and illnesses in talented female athletes.

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.

Incidence and risk factors of injuries and their impact on academic success: A prospective study in PETE students.

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.

The water channel AQP1 is expressed in human atherosclerotic vascular lesions and AQP1 deficiency augments angiotensin II-induced atherosclerosis in mice.

AIM: The water channel aquaporin 1 (AQP1) promotes endothelial cell migration. It was hypothesized that AQP1 promotes neovascularization and growth of atherosclerotic plaques. METHODS: AQP1 immunoreactivity and protein abundance was examined in human and murine atherosclerotic lesions and aortic aneurysms. Apolipoprotein E (ApoE) knockout (-/-) and AQP1-/-ApoE-/- mice were developed and fed Western diet (WD) for 8 and 16 weeks to accelerate the atherosclerosis process. In ApoE-/- and AQP1-/-ApoE-/- mice abdominal aortic aneurysms (AAA) were induced by angiotensin II (ANGII) infusion by osmotic minipumps for 4 weeks. RESULTS: In human atherosclerotic lesions and AAA, AQP1 immunoreactive protein was associated with intralesional small vessels. In ApoE-/- mouse aorta, APQ1 mRNA levels were increased with time on WD (n = 7-9, P < 0.003). Both in murine lesions at the aortic root and in the abdominal aortic aneurysmal wall, AQP1 immunoreactivity was associated with microvascular structures. The atherosclerotic lesion burden was enhanced significantly in ANGII-infused AQP1-/-ApoE-/- mice compared with ApoE-/- mice, but neither incidence nor progression of AAA was different. The aortic lesion burden increased with time on WD but was not different between ApoE-/- and AQP1-/-ApoE-/- mice at either 8 or 16 weeks (n = 13-15). Baseline blood pressure and ANGII-induced hypertension were not different between genotypes. CONCLUSION: AQP1 is expressed in atherosclerotic lesion neovasculature in human and mouse arteries and AQP1 deficiency augments lesion development in ANGII-promoted atherosclerosis in mice. Normal function of AQP1 affords cardiovascular protection.

P/Q-type and T-type voltage-gated calcium channels are involved in the contraction of mammary and brain blood vessels from hypertensive patients.

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.

A new clinical test for measurement of lower limb specific range of motion in football players: Design, reliability and reference findings in non-injured players and those with long-standing adductor-related groin pain.

OBJECTIVE: The association between groin pain and range of motion is poorly understood. The aim of this study was to develop a test to measure sport specific range of motion (SSROM) of the lower limb, to evaluate its reliability and describe findings in non-injured (NI) and injured football players. DESIGN: Case-controlled. SETTING: 6 Dutch elite clubs, 6 amateur clubs and a sports medicine practice. PARTICIPANTS: 103 NI elite and 83 NI amateurs and 57 football players with unilateral adductor-related groin pain. MAIN OUTCOME MEASURES: Sport specific hip extension, adduction, abduction, internal and external rotation of both legs were examined with inclinometers. Test-retest reliability (ICC), standard error of measurement (SEM) and minimal detectable change (MDC) were calculated. Non-injured players were compared with the injured group. RESULTS: Intra and inter tester ICCs were acceptable and ranged from 0.90 to 0.98 and 0.50-0.88. SEM ranged from 1.3 to 9.2° and MDC from 3.7 to 25.6° for single directions and total SSROM. Both non-injured elite and amateur players had very similar total SSROM in non-dominant and dominant legs (188-190, SD ± 25). Injured players had significant (p < 0.05) total SSROM deficits with 187(SD ± 31)° on the healthy and 135(SD ± 29)° on the injured side. CONCLUSION: The SSROM test shows acceptable reliability. Loss of SSROM is found on the injured side in football players with unilateral adductor-related groin pain. Whether this is the cause or effect of groin pain cannot be stated due to the study design. Whether restoration of SSROM in injured players leads to improved outcomes should be investigated in new studies.

Animal Models Used to Explore Abdominal Aortic Aneurysms: A Systematic Review.

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.

Sports injuries and illnesses during the European Youth Olympic Festival 2013.

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.

Differences in injury risk and characteristics between Dutch amateur and professional soccer players.

OBJECTIVES: To compare the incidence and characteristics of injuries between Dutch amateur and professional male soccer players during one entire competition season. DESIGN: A prospective two-cohort design. METHODS: During the 2009-2010 season, 456 Dutch male amateur soccer players and 217 professional players were prospectively followed. Information on injuries and individual exposure to all soccer activities were recorded in both cohorts. Injuries were recorded using the time-loss definition. RESULTS: In total, 424 injuries were recorded among 274 of the amateur players (60.1% injured players) and 286 injuries were sustained by 136 (62.7% injured players) of the professional players (p=0.52). Compared to the professionals, the injury incidence during training sessions was higher among amateurs (p=0.01), but the injury incidence among professionals was higher during matches (p<0.001). Professional players also had a higher incidence of minimal injuries (p<0.001), whereas the incidence of moderate and severe injuries was higher for amateurs (all p<0.001). Lastly, professional players sustained more overuse injuries (p=0.02), whereas amateurs reported more recurrent injuries (p<0.001). CONCLUSIONS: The above-mentioned differences in injury rates between amateur and professional players in the Netherlands might be explained by the difference in the level at which they play, since factors like the availability of medical support and/or the team size may influence the injury risk and characteristics.

Salt sensitivity of renin secretion, glomerular filtration rate and blood pressure in conscious Sprague-Dawley rats.

AIM: We hypothesized that in normal rats in metabolic steady state, (i) the plasma renin concentration (PRC) is log-linearly related to Na(+) intake (NaI), (ii) the concurrent changes in mean arterial pressure (MABP) and glomerular filtration rate (GFR) are negligible and (iii) the function PRC = f(NaI) is altered by ß1-adrenoceptor blockade (metoprolol) and surgical renal denervation (DNX). METHODS: In catheterized, conscious rats on low-Na(+) diet (0.004% Na(+)), NaI was increased by up to 120-fold, in four 3-day steps, by intravenous saline infusion. MABP was recorded continuously, PRC measured in arterial blood, and GFR estimated by inulin clearance. RESULTS: Steady states were achieved within 3 days. PRC [mIU L(-1)] was log-linearly related to NaI [mmol kg(-1) day(-1)]: PRC = -9.9 log (NaI) + 22. Set point (22 mIU L(-1) at NaI = 1) and slope (9.9 mIU per decade NaI) were independent of metoprolol administration and DNX. MABP and GFR were markedly salt-sensitive: MABP [mmHg] = 4.9 log (NaI) + 99 (P < 0.01), and GFR [mL min(-1)] = 1.4 log (NaI) + 8.3 (P < 0.01). MABP increased similarly (approx. 10%, P < 0.001) irrespective of pre-treatment. Metoprolol, but not DNX, reduced MABP, HR, and GFR (all P < 0.01). Salt sensitivity of GFR was not observed in DNX rats. CONCLUSION: Log-linear relations to sodium intake exist not only for PRC, but also for MABP and GFR, which per 10-fold increase in sodium intake rose by 5 mmHg and 1.4 mL min(-1) respectively. Steady-state levels of PRC appear independent of renal nerves. MABP and GFR seem markedly salt sensitive in normal rats.

Redox-linked structural changes in ribonucleotide reductase.

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.

Patients' experiences with quality of hospital care: the Consumer Quality Index Cataract Questionnaire.

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.

Exercise participation and self-rated health: do common genes explain the association?

The purpose of this study is to investigate whether there is an association between exercise participation and self-rated health and whether this association can be explained by common genes and/or common environmental influences. In a sample of 5,140 Dutch adult twins and their non-twin siblings from 2,831 families, exercise participation (sedentaries, light or moderate, vigorous exercisers) and self-rated health were assessed by survey. To investigate the etiology of the association, bivariate genetic models using structural equation modeling were applied to the data. The correlation between exercise participation and self-rated health is significant but modest (r = 0.20). Exercise participation and self-rated health are both heritable (around 50% of the variance of both phenotypes is explained by genetic factors). The genetic factors influencing exercise participation and self-rated health partially overlap (r = 0.36) and this overlap fully explains their phenotypic correlation. We conclude that the association between exercise and self-rated health can be explained by genes predisposing to both exercise participation and self-rated health. These genes may directly influence both phenotypes (pleiotropy). Alternatively, genes that affect exercise or self-rated health may indirectly influence the other phenotype through a causal relationship. We propose that identification of the genes that cause differences in exercise behavior will help resolve the issue of causality.

The association between exercise participation and well-being: a co-twin study.

OBJECTIVE: We investigated the association between leisure time exercise participation and well-being (i.e., life satisfaction and happiness) and examined the causality underlying this association. METHOD: The association between exercise participation and well-being was assessed in around 8000 subjects, (age range 18-65 years) from The Netherlands Twin Registry (NTR). Causality was tested with the co-twin control method in 162 monozygotic (MZ) twin pairs, 174 dizygotic (DZ) twin and sibling pairs, and 2842 unrelated individuals. RESULTS: Exercisers were more satisfied with their life and happier than non-exercisers at all ages. The odds ratio for life satisfaction given exercise participation was significantly higher than unity in unrelated pairs, and a trend was visible in DZ pairs. In MZ pairs, the odds ratio was close to unity. The pattern of odds ratios for happiness given exercise participation was similar. CONCLUSION: Exercise participation is associated with higher levels of life satisfaction and happiness. This association is non-causal and appears to be mediated by genetic factors that influence both exercise behavior and well-being.

High-field pulsed electron-electron double resonance spectroscopy to determine the orientation of the tyrosyl radicals in ribonucleotide reductase.

Class I ribonucleotide reductases (RNRs) are composed of two subunits, R1 and R2. The R2 subunit contains the essential diferric cluster-tyrosyl radical (Y.) cofactor, and R1 is the site of the conversion of nucleoside diphosphates to 2'-deoxynucleoside diphosphates. It has been proposed that the function of the tyrosyl radical in R2 is to generate a transient thiyl radical (C439.) in R1 over a distance of 35 A, which in turn initiates the reduction process. EPR distance measurements provide a tool with which to study the mechanism of radical initiation in class I RNRs. These types of experiments at low magnetic fields and frequencies (0.3 T, 9 GHz) give insight into interradical distances and populations. We present a pulsed electron-electron double resonance (PELDOR) experiment at high EPR frequency (180-GHz electron Larmor frequency) that detects the dipolar interaction between the Y.s in each protomer of RNR R2 from Escherichia coli. We observe a correlation between the orientation-dependent dipolar interaction and their resolved g-tensors. This information has allowed us to define the relative orientation of two radicals embedded in the active homodimeric protein in solution. This experiment demonstrates that high-field PELDOR spectroscopy is a powerful tool with which to study the assembly of proteins that contain multiple paramagnetic centers.