50 resultados para Ischemia and reperfusion injury


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 This thesis explored the relationship between attributions of responsibility for motor vehicle accidents and post-injury outcomes among a large sample of TAC clients. Results demonstrated that, despite similar levels of physical injury, people who attribute responsibility for accidents to other persons or circumstances experience poorer physical and mental health recovery in comparison to those who attribute responsibility to themselves.

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BackgroundMajor depressive disorder (MDD) is an independent risk factor for coronary heart disease (CHD), and influences the occurrence and prognosis of cardiovascular events. Although there is evidence that antidepressants may be cardioprotective after acute myocardial infarction (AMI) comorbid with MDD, the operative pathophysiological mechanisms remain unclear. Our aim was therefore to explore the molecular mechanisms of escitalopram on myocardial apoptosis and the expression of Bax and Bcl-2 in a rat model of depression during myocardial ischemia/reperfusion (I/R).MethodsRats were divided randomly into 3 groups (n = 8): D group (depression), DI/R group (depression with myocardial I/R) and escitalopram + DI/R group. The rats in all three groups underwent the same chronic mild stress and separation for 21 days, at the same time, in the escitalopram + DI/R group, rats were administered escitalopram by gavage (10 mg/kg/day). Ligation of the rat¿s left anterior descending branch was done in the myocardial I/R model. Following which behavioral tests were done. The size of the myocardial infarction was detected using 1.5% TTC dye. The Tunel method was used to detect apoptotic myocardial cells, and both the Rt-PCR method and immunohistochemical techniques were used to detect the expression of Bcl¿2 and Bax.ResultsCompared with the D and DI/R groups, rats in Escitalopram + DI/R group showed significantly increased movements and sucrose consumption (P < .01). Compared with the DI/R group, the myocardial infarct size in the escitalopram + DI/R group was significantly decreased (P < .01). Compared with the D group, there were significantly increased apoptotic myocardial cells in the DI/R and escitalopram + DI/R groups (P < .01); however compared with the DI/R group, apoptotic myocardial cell numbers in the escitalopram + DI/R group were significantly decreased (P < .01). Compared with the DI/R group, there was a down-regulated Bax:Bcl-2 ratio in the escitalopram + DI/R group (P < .01).ConclusionsThese results suggest that in patients with AMI comorbid with MDD, there is an increase in pro-apoptotic pathways that is reversed by escitalopram. This suggests that clinically escitalopram may have a direct cardioprotective after acute myocardial infarction.

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BACKGROUND AND PURPOSE : Annexin-A1 (ANX-A1) is an endogenous, glucocorticoid-regulated anti-inflammatory protein. The N-terminal-derived peptide Ac-ANX-A12–26 preserves cardiomyocyte viability, but the impact of ANX-A1-peptides on cardiac contractility is unknown. We now test the hypothesis that ANX-A1 preserves post-ischaemic recovery of left ventricular (LV) function.

EXPERIMENTAL APPROACH : Ac-ANX-A12–26 was administered on reperfusion, to adult rat cardiomyocytes as well as hearts isolated from rats, wild-type mice and mice deficient in endogenous ANX-A1 (ANX-A1–/–). Myocardial viability and recovery of LV function were determined.

KEY RESULTS: Ischaemia–reperfusion markedly impaired both cardiomyocyte viability and recovery of LV function by 60%. Treatment with exogenous Ac-ANX-A12–26 at the onset of reperfusion prevented cardiomyocyte injury and significantly improved recovery of LV function, in both intact rat and wild-type mouse hearts. Ac-ANX-A12–26 cardioprotection was abolished by either formyl peptide receptor (FPR)-nonselective or FPR1-selective antagonists, Boc2 and cyclosporin H, but was relatively insensitive to the FPR2-selective antagonist QuinC7. ANX-A1-induced cardioprotection was associated with increased phosphorylation of the cell survival kinase Akt. ANX-A1−/− exaggerated impairment of post-ischaemic recovery of LV function, in addition to selective LV FPR1 down-regulation.

CONCLUSIONS AND IMPLICATIONS : These data represent the first evidence that ANX-A1 affects myocardial function. Our findings suggest ANX-A1 is an endogenous regulator of post-ischaemic recovery of LV function. Furthermore, the ANX-A1-derived peptide Ac-ANX-A12–26 on reperfusion rescues LV function, probably via activation of FPR1. ANX-A1-based therapies may thus represent a novel clinical approach for the prevention and treatment of myocardial reperfusion injury.

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The purpose of the current study is to evaluate the cardioprotective effects of purified Salvia miltiorrhiza extract (PSME) on myocardial ischemia/reperfusion injury in isolated rat hearts. Hearts were excised and perfused at constant flow (7 – 9 ml · min−1) via the aorta. Non-recirculating perfusion with Krebs-Henseleit (KH) solution was maintained at 37°C and continuously gassed with 95% O2 and 5% CO2. KH solution with or without PSME (100 mg per liter solution) was used after 30-min zero-flow ischemia for the PSME and control group, respectively. Left ventricular (LV) developed pressure; its derivatives, diastolic pressure, and so on were continuously recorded via a pressure transducer attached to a polyvinylchloride balloon that was placed in the left ventricle through an incision in the left atrium. PSME treated hearts showed significant postischemic contractile function recovery (developed pressure recovered to 44.2 ± 4.9% versus 17.1 ± 5.7%, P<0.05; maximum contraction recovered to 57.2 ± 5.9% versus 15.1 ± 6.3%, P<0.001; maximum relaxation restored to 69.3 ± 7.3% versus 15.4 ± 6.3%, P<0.001 in the PSME and control group, respectively). Significant elevation in end-diastolic pressure, which indicated LV stiffening in PSME hearts might have resulted from the excess high dose of PSME used. Further study will be conducted on the potential therapeutic value with lower dose of PSME on prevention of ischemic heart disease.

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Objective:
To quantify the burden of disease and injury for the Aboriginal and non-Aboriginal populations in the Northern Territory.

Design and setting:
Analysis of Northern Territory data for 1 January 1994 to 30 December 1998 from multiple sources.

Main outcome measures:
Disability-adjusted life-years (DALYs), by age, sex, cause and Aboriginality.

Results:
Cardiovascular disease was the leading contributor (14.9%) to the total burden of disease and injury in the NT, followed by mental disorders (14.5%) and malignant neoplasms (11.2%). There was also a substantial contribution from unintentional injury (10.4%) and intentional injury (4.9%). Overall, the NT Aboriginal population had a rate of burden of disease 2.5 times higher than the non-Aboriginal population; in the 35-54-year age group their DALY rate was 4.1 times higher. The leading causes of disease burden were cardiovascular disease for both Aboriginal men (19.1%) and women (15.7%) and mental disorders for both non-Aboriginal men (16.7%) and women (22.3%).

Conclusions:
A comprehensive assessment of fatal and non-fatal conditions is important in describing differentials in health status of the NT population. Our study provides comparative data to identify health priorities and facilitate a more equitable distribution of health funding.


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Oxidative stress plays a central role in neuronal injury and cell death in acute and chronic pathological conditions. The cellular responses to oxidative stress embrace changes in mitochondria and other organelles, notably endoplasmic reticulum, and can lead to a number of cell death paradigms, which cover a spectrum from apoptosis to necrosis and include autophagy. In Alzheimer's disease, and other pathologies including Parkinson's disease, protein aggregation provides further cellular stresses that can initiate or feed into the pathways to cell death engendered by oxidative stress. Specific attention is paid here to mitochondrial dysfunction and programmed cell death, and the diverse modes of cell death mediated by mitochondria under oxidative stress. Novel insights into cellular responses to neuronal oxidative stress from a range of different stressors can be gained by detailed transcriptomics analyses. Such studies at the cellular level provide the key for understanding the molecular and cellular pathways whereby neurons respond to oxidative stress and undergo injury and death. These considerations underpin the development of detailed knowledge in more complex integrated systems, up to the intact human bearing the neuropathology, facilitating therapeutic advances.

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Objective To see whether concerns about injury risk relate to children's physical activity (PA).
Methods Two cohorts were recruited from 19 Australian schools and assessed in 2001 (T1), 2004 (T2) and 2006 (T3). The younger (n=162) was assessed at 6, 9 and 11years old, and the older (n=259) at 11, 14 and 16 years old. At T1 and T2, parents of the younger cohort reported on fear of child being injured, and whether child would be at risk of injury if they played organised sport; the older cohort self-reported injury fear. Accelerometers assessed PA at each time point. Linear regression models examined cross-sectional associations, and also associations between T1 injury fear and risk and T2 PA, and T2 injury fear and risk and T3 PA.
Results In the younger cohort at T2 (9 years), fear and risk were both negatively associated with moderate to vigorous PA (MVPA) (β=−0.17, 95% CI −0.30 to −0.03 and β=−0.26, 95% CI −0.41 to −0.10) and also vigorous PA (VPA). Fear was also associated with moderate PA (MPA). For the older cohort at T1, injury fear was negatively associated with MVPA (β=−0.21, 95% CI −0.35 to −0.07) and also MPA and VPA. Parental perception of risk at T1 (6 years) was negatively associated with children's MPA at T2 (9 years) (β=−0.17, 95% CI −0.32 to −0.02). Sex did not moderate any association.
Conclusions Younger children and their parents need to know which sports have low injury risks. Some children may need increased confidence to participate.

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Background Hospitalised sport and active recreation injuries can have serious long-term consequences. Despite this, few studies have examined the long-term outcomes of these injuries. The purpose of this study was to establish whether patients hospitalised with orthopaedic sport and active recreation injuries, have returned to their pre-injury levels of health status and function, 12 months post injury and identify factors associated with poor outcomes. The present work was a cohort study with retrospective assessment of pre-injury status and prospective assessment of outcome at 12 months post injury.

Methods Adults with orthopaedic sport and active recreation injuries, captured by the Victorian Orthopaedic Trauma Outcomes Registry were recruited to the study. Pre-injury and 12-month outcomes were assessed using the 36-item Short Form Health Survey (SF-36) and the extended Glasgow Outcome Scale. Differences in pre-injury and post-injury SF-36 scores were examined and demographic, injury, hospital and physical activity variables were assessed for associations with outcome using multivariate linear regression.

Results Of the 324 participants 98% were followed-up at 12 months post injury. At 12 months, participants reported a mean 7.0-point reduction in physical health (95% CI 5.8 to 7.8) and a 2.5-point reduction in mental health (95% CI 1.2 to 3.0), with 58% (95% CI 52.6% to 63.4%) reporting reduced function. Sporting group (p=0.001), Injury Severity Score >15 (p=0.007) and high pre-injury vigorous activity levels (p=0.04), were related to poorer physical health outcomes.

Conclusions At 12 months post injury, most participants reported large reductions in physical health and reduced function. This information is important for furthering our understanding of the burden of sport and active recreation injury and setting priorities for treatment and rehabilitation.

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Background—To minimise injury risk and maximise gymnastics performance, coaches, parents, and health professionals working with young gymnasts need to understand and practise safe gymnastics.

Aims—To (a) identify the various injury counter measures specific to gymnastics, (b) critically review the literature describing each injury prevention measure, and (c) assess, using available risk factor and injury data, the weight of evidence to support each of these counter measures. Specific recommendations for further research and implementation strategies to prevent injury and improve safety are also given.

Methods—The relevant literature was identified through the use of Medline (1966 to May 1998) and SPORT Discus (1975 to May 1998) searches, hand searching of journals and reference lists, and discussions with key Australian gymnastics organisations.

Results—The key gymnastics injury counter measures identified in this review include coaching (physical preparation, education, spotting, and performance technique), equipment, and the health support system (medical screening, treatment, and rehabilitation). Categorisation of the type of evidence for the effectiveness of each of these counter measures in preventing injury showed that most of it is based on informal opinion/anecdotal evidence, uncontrolled data based studies, and several prospective epidemiological studies. There is no evidence from formally controlled trials or specific evaluation studies of counter measures for gymnastics.

Conclusions—Although gymnastics is a sport associated with young participants and frequent high volume, high impact training, there is a paucity of information on injury risk factors and the effectiveness of injury practices. Further controlled trials are needed to examine the extent to which injury prevention counter measures can prevent or reduce the occurrence of injury and re-injury. Particular attention should be devoted to improving training facilities, the design and testing of apparatus and personal equipment used by gymnasts, and coaching and the role of spotting in preventing injury.

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The study aim was to address healthcare workers’ and patients’ questions about the likely level of recovery at 6 months of patients admitted to an Australian intensive care unit (ICU). Ninety-three consecutive, eligible adults were identified and followed prospectively. Severity of illness on admission was assessed using Acute Physiological and Chronic Health Evaluation (APACHE II), while functional status at 6 months was evaluated using the Sickness Impact Profile (SIP). Cumulative mortality was 25%. Admission severity of illness was associated with survival at 6 months (P≤0.001). Fifty-one (78%) of the 70 survivors were interviewed. Admission severity of illness scores correlated with functional status at 6 months (r=0.34, P=0.01), a finding reported in only one other study. More than half of those interviewed had returned to near pre-admission functional status. Those with poor functional status included high proportions of people with chronic illness and head injury. Overall, physical recovery was more complete than psychosocial recovery. The findings provide useful information for addressing questions relating to physical and psychosocial recovery, appetite, sleep patterns and return to work post discharge.

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Objective: To evaluate the effectiveness of a preseason physical training programme that taught landing and falling skills in improving landing skills technique and preventing injury in junior elite Australian football players.

Methods: 723 male players who participated in an under 18 elite competition were studied prospectively in a non-randomised controlled trial over two consecutive football seasons. There were 114 players in the intervention group and 609 control players. The eight session intervention programme taught players six landing, falling, and recovery skills, which were considered fundamental for safe landing in Australian football. Landing skills taught in these sessions were rated for competence by independent and blinded assessors at baseline and mid-season.

Results: Evaluation of landing skills found no significant differences between the groups at baseline. Evaluation after the intervention revealed overall improvement in landing skills, but significantly greater improvement in the intervention group (z = –7.92, p = 0.001). Players in the intervention group were significantly less likely (relative rate 0.72, 95% confidence interval 0.52 to 0.98) to sustain an injury during the season than the control group. In particular, the time to sustaining a landing injury was significantly less for the intervention group (relative rate 0.40, 95% confidence interval 0.17 to 0.92) compared with the control group.

Conclusions:
Landing and falling ability can be taught to junior elite Australian football players. Players in the intervention group were protected against injury, particularly injuries related to landing and falls.

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Background: Motorcycle crash victims form a high proportion of those killed or injured in road traffic accidents. Injuries to the head, following motorcycle crashes, are a common cause of severe morbidity and mortality. It seems intuitive that helmets should protect against head injuries but it has been argued that motorcycle helmet use decreases rider vision and increases neck injuries. This review will collate the 'current available evidence on helmets and their impact on mortality, and head, face and neck injuries following motorcycle crashes.

Objectives: To quantify the effectiveness of wearing a motorcycle helmet in reducing mortality and head and neck injury following motorcycle crashes.

Search strategy: Databases including the Cochrane Injuries Group Specialised Register, Cochrane Central Register of Controlled Trials (The Cochrane Library issue 1,2003), MEDLINE (January 1966 to February 2003), EMBASE (January 1985 to February 2003), CINAHL (January 1982 to February 2003), IRRD (International Road Research Documentation), TRANSDOC, TRIS (Transport Research Information Service), ATRI (Australian Transport Index) (1976 to Feb 2003), Science Citation Index were searched for relevant articles. Web sites of traffic and road accident research bodies including government agencies were also searched. Reference lists from topic reviews, identified studies and bibliographies were examined for relevant articles.

Selection criteria: We considered for inclusion studies that investigated a population of motorcycle riders who had crashed, examining helmet use as an intervention and with outcomes that included one or more of the following: death, head, neck or facial injury. Studies included any that compared an intervention and control group and, therefore, included any randomised controlled trials, non-randomised controlled trials, cohort, case-control and cross-sectional studies. Ecological and case series studies were excluded.

Data collection and analysis: Two reviewers independently screened reference lists for eligible articles. Two reviewers independently assessed articles for inclusion criteria. Data were abstracted by two independent reviewers using a standard abstraction form.

Main results: Fifty-three observational studies were identified of varying quality. Despite methodological differences there was a remarkable consistency in results, particularly for mortality and head injury outcomes. Motorcycle helmets appear to reduce the risk of mortality although, due to heterogeneity in study design, an overall estimate of effect was not calculated. There was some evidence that the effect of helmets on mortality is modified by speed. Motorcycle helmets were found to reduce the risk of head injury and from five well-conducted studies the risk reduction is estimated to be 72% (OR 0.28, 95%CI 0.23,0.35). Insufficient evidence was found to estimate the effect of motorcycle helmets compared with no helmet on facial or neck injuries. However, studies of poorer quality suggest that helmets have no effect on the risk of neck injuries and are protective for facial injury. There was insufficient evidence to demonstrate whether differences in helmet type confer more or less advantage in injury reduction.

Conclusions:
Motorcycle helmets reduce the risk of mortality and head injury in motorcycle riders who crash, although the former effect may be modified by other crash factors such as speed. Further well-conducted research is required to determine the effects of helmets and different helmet types on mortalIty, head, neck and facial injuries. However, the findings suggest that global efforts to reduce road traffic injuries may be facilitated by increasing helmet use by motorcyclists.

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Objective To investigate the incidence of falls and explore fall prevention practices at acute care hospitals in Singapore.

Design A retrospective audit to collect baseline data on (1) incidence of falls (patient fall rates and fall injury rates) and (2) fall prevention practices, was conducted in five acute care hospitals in Singapore from December 2004 to March 2005.

Study participants Medical record data (n = 6000) of patients admitted into the medical, surgical and geriatric units in the five hospitals.

Outcome measures Fall incidence was obtained from the hospital's fall databases and incident reports for the period of June 2003 to May 2004. In total, 6000 medical records from five hospitals were randomly selected, retrieved and reviewed to determine whether falls, fall assessments and interventions were being initiated and documented.

Results The number of fallers for all hospitals was 825. Analysis showed that patient fall rates ranged from 0.68 to 1.44 per 1000 patient days, and the proportion of falls associated with injury ranged from 27.4% to 71.7%. The use of a fall risk assessment tool by nurses was recorded in 77% of all the nursing records.

Conclusion This study has laid the foundation for further research for fall prevention in Singapore by describing current fall rates, fall-associated injury rates and the status of fall prevention practices in acute care settings. The results will be used to inform the development of a tailored multifaceted strategy to facilitate the implementation of Fall Prevention Clinical Practice Guidelines to reduce the burden of falls and fall injuries in hospitals in Singapore.