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Long-chain omega-3 polyunsaturated fatty acid (LC n -3 PUFA) supplements, rich in eicosapentaenoic acid and/or docosahexaenoic acid, are increasingly being recommended within athletic institutions. However, the wide range of doses, durations and study designs implemented across trials makes it difficult to provide clear recommendations. The importance of study design characteristics in LC n -3 PUFA trials has been detailed in cardiovascular disease research, and these considerations may guide LC n -3 PUFA study design in healthy cohorts. This systematic review examined the quality of studies and study design considerations used in evaluating the evidence for LC n -3 PUFA improving performance in physically trained adults. SCOPUS, PubMed and Web of Science electronic databases were searched to identify studies that supplemented LC n -3 PUFA in physically trained participants. Forty-six (n = 46) studies met inclusion. Most studies used a randomised control design. Risk of bias, assessed using the design-appropriate Cochrane Collaboration tool, revealed that studies had a predominant judgment of 'some concerns', 'high risk' or 'moderate risk' in randomised controlled, randomised crossover or non-randomised studies, respectively. A custom five-point quality assessment scale demonstrated that no study satisfied all recommendations for LC n -3 PUFA study design. This review has highlighted that the disparate range of study designs is likely contributing to the inconclusive state of outcomes pertaining to LC n -3 PUFA as a potential ergogenic aid. Further research must adequately account for the specific LC n -3 PUFA study design considerations, underpinned by a clear hypothesis, to achieve evidence-based dose, duration and composition recommendations for physically trained individuals. [ABSTRACT FROM AUTHOR]

Research skills are fundamental to the building of the evidence basis of professional practice, are at the core of lifelong professional learning and are the keys to discovery, innovation and knowledge transfer. Research competency is thus increasingly recognised as an important educational goal for graduates in many professions. This paper describes a flexible program, adaptable to any professional course of study that allows students to engage in meaningful, scholarly and authentic research. Students are supported to undertake a research activity that spans the research continuum from development of a research question through to dissemination of findings, and strategic points in-between.

Research is increasingly recognised as a key component of medical curricula, offering a range of benefits including development of skills in evidence-based medicine. The literature indicates that experienced academic supervision or mentoring is important in any research activity and positively influences research output. The aim of this project was to investigate the human research ethics experiences and knowledge of three groups: medical students, and university academic staff and clinicians eligible to supervise medical student research projects; at two Australian universities. Training in research ethics was low amongst academic staff and clinicians eligible to supervise medical student research. Only two-thirds of academic staff (67.9 %) and students (65.7 %) and less than half of clinicians surveyed (47.1 %; p = 0.014) indicated that specific patient consent was required for a doctor to include patient medical records within a research publication. There was limited awareness of requirements for participant information and consent forms amongst all groups. In the case of clinical trials, fewer clinicians (88.4 %) and students (83.3 %) than academics (100 %) indicated there was a requirement to obtain consent (p = 0.009). Awareness of the ethics committee focus on respect was low across all groups. This project has identified significant gaps in human research ethics understanding among medical students, and university academic staff and clinicians. The incorporation of research within medical curricula provides the impetus for medical schools and their institutions to ensure that academic staff and clinicians who are eligible and qualified to supervise students' research projects are appropriately trained in human research ethics.

Clinically and experimentally, a case for omega-3 polyunsaturated fatty acid (PUFA) cardioprotection in females has not been clearly established. The goal of this study was to investigate whether dietary omega-3 PUFA supplementation could provide ischemic protection in female mice with an underlying genetic predisposition to cardiac hypertrophy. Mature female transgenic mice (TG) with cardiac-specific overexpression of angiotensinogen that develop normotensive cardiac hypertrophy and littermate wild-type (WT) mice were fed a fish oil-derived diet (FO) or PUFA-matched control diet (CTR) for 4 wk. Myocardial membrane lipids, ex vivo cardiac performance (intraventricular balloon) after global no-flow ischemia and reperfusion (15/30 min), and reperfusion arrhythmia incidence were assessed. FO diet suppressed cardiac growth by 5% and 10% in WT and TG, respectively (P < 0.001). The extent of mechanical recovery [rate-pressure product (RPP) = beats/min x mmHg] of FO-fed WT and TG hearts was similar (50 [+ or -] 7% vs. 45 [+ or -] 12%, 30 min reperfusion), and this was not significantly different from CTR-fed WT or TG. To evaluate whether systemic estrogen was masking a protective effect of the FO diet, the responses of ovariectomized (OVX) WT and TG mice to FO dietary intervention were assessed. The extent of mechanical recovery of FO-fed OVX WT and TG (RPP, 50 [+ or -] 4% vs. 64 [+ or -] 8%) was not enhanced compared with CTR-fed mice (RPP, 60 [+ or -] 11% vs. 80 [+ or -] 8%, P = 0.335). Dietary FO did not suppress the incidence of reperfusion arrhythmias in WT or TG hearts (ovary-intact mice or OVX). Our findings indicate a lack of cardioprotective effect of dietary FO in females, determined by assessment of mechanical and arrhythmic activity postischemia in a murine ex vivo heart model. polyunsaturated fatty acids; ischemia-reperfusion; Langendorff perfused hearts

Regular fish consumption, a rich source of long-chain omega-3 (ω-3) docosahexaenoic acid (DHA), modifies cardiac electrophysiology. However, human studies investigating fish oil and cardiac electrophysiology have predominantly supplemented therapeutic (high) doses of fish oil (often ω-3 eicosapentaenoic acid (EPA) rich sources). This study examined whether non-therapeutic doses of DHA-rich fish oil modulate cardiac electrophysiology at rest and during cardiovascular reflex challenges to the same extent, if at all, in young healthy adults. Participants (N = 20) were supplemented (double-blinded) with (2x1g.day−1) soy oil (Control n = 9) or DHA-rich tuna fish oil (FO n = 11) providing DHA: 560 mg and EPA: 140 mg. The Omega-3 Index (O3I; erythrocyte membrane % EPA + DHA), heart rate (HR) and HR variability (HRV) were analyzed during rest, maximal isometric handgrip and cold diving reflex challenges at baseline and following 8 weeks. The baseline O3I (Control: 5.1 ± 1.0; FO: 5.4 ± 0.9; P > 0.05), resting HR (Control: 65 ± 12bpm; FO: 66 ± 8bpm; P > 0.05) and HRV metrics did not significantly differ between the groups prior to supplementation. Relative to the control group, the O3I was increased (Control: 5.0 ± 1.1; FO: 7.8 ± 1.2; P < 0.001), and resting HR was slowed in the FO group following supplementation (Control: 66 ± 9bpm; FO: 61 ± 6bpm; P = 0.046). However, no significant (P > 0.05) between-group differences were observed in HR responsiveness or any indices of HRV during reflex challenges. In young healthy adults, dietary achievable doses of ω-3 DHA-rich fish oil exerted a direct slowing effect on resting HR, without compromising the HR response to either dominant sympathetic or parasympathetic modulation. [ABSTRACT FROM AUTHOR]

Dietary fish oil, providing docosahexaenoic acid (DHA) modulates oxygen consumption and fatigue in animal models. However, in humans predominately supplemented with high eicosapentaenoic acid (EPA), there is no evidence of endurance performance enhancement. Therefore, this study examined if DHA-rich fish oil could improve repeated bouts of physiologically stressful cycling and a subsequent time trial in a state of fatigue. Twenty-six trained males took part in a double-blind study and were supplemented with either 2 x 1g/day soy oil, Control) or DHA-rich tuna fish oil (Nu-Mega) (FO) (560mg DHA / 140mg eicosapentaenoic acid (EPA), for 8 weeks. Maximal cycling power (3 X 6s), isometric quadriceps strength (MVC), Wingate cycling protocol (6 x 30s) and a 5min cycling time-trial were assessed at baseline and eight weeks. The Omega-3 Index was not different at baseline (Control: 4.2 ± 0.2; FO: 4.7 ± 0.2%) and increased in the FO group after eight weeks (Control: 3.9 ± 0.2; FO: 6.3 ± 0.3%, p < .01). There was no effect of DHA-rich fish oil on power output of maximal 6s cycle sprinting (Control: pTe 1100 ± 49 Post 1067 ± 51; FO: Pre 1070 ± 46 Post 1042 ± 46W), during 5min time trail (Control: Pre 267 ± 19 Post 278 ± 20; FO: Pre 253 ± 16 Post 265 ± 16 W) or maximal voluntary contraction force (Control: Pre 273 ± 19 Post 251 ± 19; FO: Pre 287 ± 17 Post 283 ± 16 Nm). Nevertheless, relative oxygen consumption was reduced the FO group during the cycling time trial (Control: -23 ± 26; FO: -154 ± 59ml O2/min/100W p < .05) suggesting improved economy of cycling. We conclude that DHA-rich fish oil, successful at elevating the Omega-3 Index, and reflective of skeletal muscle membrane incorporation, can modulate oxygen consumption during intense exercise. [ABSTRACT FROM AUTHOR]

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This study tested the hypothesis that in vivo antiarrhythmic effects of dietary fish oil can be attributed directly to changes in myocardial properties. Sixty adult male rats were fed a fish oil diet (FO), an isoenergetic saturated fat diet (SAT) or a low fat reference diet (REF) for 16 wk. hearts isolated from these rats were perfused with washed porcine erythrocytes (0.4 hematocrit) in working heart mode. Dietary fish oil prevented reperfusion-induced ventricular fibrillation (VF) (% of rats with VF: REF 50%, SAT 80% P = 0.35, FO 0% P < 0.05 n = 10) and reduced arrhythmias in ischemia. In a separate set of hearts from rats fed the three diets, FO increased while SAT reduced the stimulation threshold for programmed electrical induction of VF during control perfusion compared with REF (mean [+ or -] SD: REF 7.1 [+ or -] 0.2 mA; SAT 5.8 [+ or -] 0.2 mA, P < 0.001; FO 15.1 [+ or -] 1.0 mA, P < 0.001, n = 10) and during subsequent ischemia (REF 5.9 [+ or -] 0.2 mA; SAT 3.8 [+ or -] 0.3 mA, P < 0.001; FO 8.9 [+ or -] 0.2 mA, P < 0.001, n = 10). The isolated working heart model used physiological workload and oxygenation but excluded extracardiac influences. Dietary fish oil prevented the initiation and reduced the severity of arrhythmias in the isolated hearts in response to a variety of stimuli. These results establish that irrespective of any effects on blood pressure or platelet function in vivo, dietary fish oil directly affects myocardial properties which may contribute to observed clinical reductions in cardiac mortality associated with fish consumption. INDEXING KEY WORDS: dietary fats (n-3) fatty acids; myocardial ischemia; arrhythmia; rats

Previous research showed that dietary fish oil was potently antiarrhythmic in rats but olive oil was not. This study was designed to test the hypothesis that canola oil, another major dietary source of oleic acid additionally containing the (n-3) polyunsaturated fatty acid [Alpha]-linolenic acid [18:3(n-3)], can reduce vulnerability to cardiac arrhythmia in rats. Rats were randomly assigned to one of four experimental diet groups for 12 wk. The fat source in the diets was 12% olive (63% oleic acid), canola (55% oleic, 8% [Alpha]-linolenic acid), soybean [50% linoleic 18:2(n-6), 7% [Alpha]-linolenic acid] or sunflower seed oil (64% linoleic acid). Arrhythmias were induced by coronary artery occlusion and reperfusion. Incidence of ventricular fibrillation, mortality and arrhythmia score during reperfusion were significantly lower in rats fed the diet containing canola oil than in those fed the olive oil diet. No difference in the severity of arrhythmias was seen in groups fed diets containing soybean or sunflower seed oils. Analysis of myocardial phospholipid fatty acids showed that consumption of canola oil decreased the ratio of (n-6)/(n-3) polyunsaturated fatty acids relative to the other diets, as does dietary fish oil. These results suggest that regular substitution of canola oil for other dietary lipid sources may assist in reducing the likelihood of a transient ischemic event leading to life-threatening cardiac arrhythmias, but the effectiveness of [Alpha]-linolenic acid is reduced by high levels of linoleic acid. INDEXING KEY WORDS: reperfusion; (n-3) fatty acids; canola; arrhythmia; [Alpha]-linolenic acid; rats

This pilot study sought to determine whether a low, supplemental intake of fish oil would raise the Omega‐3 Index (O3I) and improve physical fitness in healthy older adults. Participants (70 ± 3 years) were randomised to 2 g/day of either sunola oil (control; n = 8, 62.5% female) (1700 mg/day oleic acid) or docosahexaenoic acid (DHA)‐rich fish oil (FO; n = 9, 55.6% female) [delivering 560 mg/day DHA and 140 mg/day eicosapentaenoic acid (EPA)] for 16 weeks. The O3I, physical fitness, 400 m walking speed and heart rate (HR) parameters were assessed. O3I was increased after FO (mean ± SD, control: pre 6.1 ± 0.8, post 5.9 ± 0.6; FO: pre 6.0 ± 0.6, post 8.3 ± 1.2 p < 0.05). Mean lowest overnight HR (control: pre 58 ± 6, post 58 ± 6; FO: pre 55 ± 6, post 52 ± 6 bpm, p < 0.05) and mean HR during fast walking (control: pre 120 ± 6, post 124 ± 7; FO: pre 122 ± 6, post 115 ± 6 bpm, p < 0.01) were reduced in the FO group without a change in walking speed (control: pre 1.55 ± 0.17, post 1.58 ± 0.20; FO: pre 1.59 ± 0.15, post 1.59 ± 0.18 m/s), HR variability or physical fitness. The changes in lowest resting HR and fast walking HR significantly correlated (inversely) with the changes in O3I. This nutritional approach of providing dietary achievable DHA offers a potential opportunity to reduce cardiovascular strain during physical activity in the older adult. [ABSTRACT FROM AUTHOR]

Heart rate variability (HRV) is often measured during clinical and experimental cardiovascular reflex tests (CRT), as a reflection of cardiac autonomic modulation, despite limited characterization of the rapid responses that occur. Therefore, we evaluated the responsiveness of HRV indices in 20 healthy young adults (age, 27 ± 6 y; mass, 76.9 ± 16.8 kg; height, 1.79 ± 0.12 m) during four separate established CRT. These included the [I] orthostatic challenge, [II] isometric handgrip, [III] cold pressor and [IV] cold diving reflex tests. Electrocardiogram was recorded throughout, with HRV derived from RR intervals at rest and from each CRT. On a separate day, a subgroup of participants (n=9) completed the same protocol for a second time. The maximal slope of heart rate change (dTdt) was significantly different between all CRT, with the orthostatic challenge producing the fastest increase (2.56 ± 0.48) and the cold pressor the fastest reduction (−1.93 ± 0.68) in heart rate. Overall HRV, reflected by Poincaré plot ratio (SD1:SD2), was significantly reduced during all CRT ([I], −0.41 ± 0.12; [II], −0.19 ± 0.05; [III], −0.36 ± 0.12; [IV], −0.44 ± 0.11; p<0.05) relative to baseline and this was reproducible in time-series. However, when HRV indices were correlated to mean-RR an exponential growth-like relationship was evident (R2 ranging from: 0.52–0.62). These unique outcomes demonstrate that short-term alterations in HRV are evident during CRT, while indicating the importance of adjusting for, or at least reporting, underlying heart rate when interpreting such measures. [ABSTRACT FROM AUTHOR]

A study was conducted to evaluate the effects of different protein sources like whey, soy, red meat and milk protein on energy intake and body weight maintenance in chronic diet-induced obese mice. Results indicated that though dietary fat remained a major factor in weight management, the type and amount of protein intake also affected weight.

Introduction: Remote communities across Australia lack the ready access to medical care generally afforded to metropolitan populations. The Royal Flying Doctor Service (RFDS) medical chest program provides medical resources to these communities allowing medications to be dispensed in conjunction with a telehealth consulting service. More than 3000 medical chests are located throughout Australia and each year the Queensland RFDS conducts approximately 20 000 telehealth consultations. The aim of this study was to review the use of the medical chest model within the state of Queensland and to analyse changes in the medical chest program from 10 years earlier to evaluate the changing healthcare needs of remote Australian populations. Methods: All telehealth consultations and items dispensed from the medical chests were reviewed over a 1-year period from 1 July 2013 and 30 June 2014. Items dispensed were categorised and compared to those in 2005-06 in absolute terms by one-way ANOVA and proportionately by χ² with Fisher's exact test. Consultations using the medical chest were categorised and compared to those in 2005-06 by χ² with Fisher's exact test. Results: The number of telehealth consultations conducted in 2013-14 (N=20 707) was not different to the number conducted in 2005-06 (N=21 470). Fewer items were dispensed from the medical chests in 2013-14 (3936 total items) than in 2005-06 (8607 total items; p<0.0001). In the specific categories of 'burns and other dressings' and 'antihistamines', the number of individual items dispensed increased. Resources from the medical chest were used more for genitourinary system consultations and less for consultations involving specific infectious diseases; the circulation, respiratory and abdominal systems; skin diseases; injury; symptoms without a diagnosis; and following other contact with a health service. Conclusions: The medical chests remain a vital tool for medical care of remote populations and the need for telehealth medical advice remains unchanged, although fewer items are being dispensed. The use of the medical chest for each diagnostic category of consultation has shown some variation over the past 10 years, reflective of changing patterns of accident, injury and disease. [ABSTRACT FROM AUTHOR]

Oxygen efficiency influences skeletal muscle contractile function during physiological hypoxia. Dietary fish oil, providing docosahexaenoic acid (DHA), reduces the oxygen cost of muscle contraction. This study used an autologous perfused rat hindlimb model to examine the effects of a fish oil diet on skeletal muscle fatigue during an acute hypoxic challenge. Male Wistar rats were fed a diet rich in saturated fat (SF), long-chain (LC) n-6 polyunsaturated fatty acids (n-6 PUFA), or LC n-3 PUFA DHA from fish oil (FO) (8 weeks). During anaesthetised and ventilated conditions (normoxia 21% O2 (SaO2-98%) and hypoxia 14% O2 (SaO2-89%)) the hindlimb was perfused at a constant flow and the gastrocnemius-plantaris-soleus muscle bundle was stimulated via sciatic nerve (2 Hz, 6-12V, 0.05 ms) to established fatigue. Caffeine (2.5, 5, 10 mM) was supplied to the contracting muscle bundle via the arterial cannula to assess force recovery. Hypoxia, independent of diet, attenuated maximal twitch tension (normoxia: 82 ± 8; hypoxia: 41 ± 2 g·g−1 tissue w.w.). However, rats fed FO sustained higher peak twitch tension compared with the SF and n-6 PUFA groups ( P < 0.05), and the time to decline to 50% of maximum twitch tension was extended (SF: 546 ± 58; n-6 PUFA: 522 ± 58; FO: 792 ± 96 s; P < 0.05). In addition, caffeine-stimulated skeletal muscle contractile recovery was enhanced in the FO-fed animals (SF: 41 ± 3; n-6 PUFA: 40 ± 4; FO: 52 ± 7% recovery; P < 0.05). These results support a physiological role of DHA in skeletal muscle membranes when exposed to low-oxygen stress that is consistent with the attenuation of muscle fatigue under physiologically normoxic conditions. [ABSTRACT FROM AUTHOR]

A definitive understanding of the role of dietary lipids in determining cardioprotection (or cardiodetriment) has been elusive. Randomized trial findings have been variable and sex specificity of dietary interventions has not been determined. In this investigation the sex-selective cardiac functional effects of three diets enriched by omega-3 or omega-6 polyunsaturated fatty acids (PUFA) or enriched to an equivalent extent in saturated fatty acid components were examined in rats after an 8-wk treatment period. In females the myocardial membrane omega-6:omega-3 PUFA ratio was twofold higher than males in the omega-6 diet replacement group. In diets specified to be high in omega-3 PUFA or in saturated fat, this sex difference was not apparent. Isolated cardiomyocyte and heart Langendorff perfusion experiments were performed, and molecular measures of cell viability were assessed. Under basal conditions the contractile performance of omega-6 fed female cardiomyocytes and hearts was reduced compared with males. Omega-6 fed females exhibited impaired systolic resilience after ischemic insult. This response was associated with increased postischemia necrotic cell damage evaluated by coronary lactate dehydrogenase during reperfusion in omega-6 fed females. Cardiac and myocyte functional parameters were not different between omega-3 and saturated fat dietary groups and within these groups there were no discernible sex differences. Our data provide evidence at both the cardiac and cardiomyocyte levels that dietary saturated fatty acid intake replacement with an omega-6 (but not omega-3) enriched diet has selective adverse cardiac effect in females. This finding has potential relevance in relation to women, cardiac risk, and dietary management. [ABSTRACT FROM AUTHOR]

Dietary fish consumption contributes to a reduced risk of cardiac mortality. In the present study, the effect of low-dose fish oil (FO) supplementation on heart rate (HR) response to intense exercise and recovery was investigated in physically fit males. The subjects (n 26) were supplemented (double-blind, parallel design) with (2 × 1 g/d) soya bean oil (control) or tuna FO providing the long-chain n-3 PUFA DHA (560 mg) and EPA (140 mg). Erythrocyte omega-3 index (%EPA+DHA), HR, HR variability and HR recovery were analysed during rest, intense exercise and recovery at baseline and after 8 weeks of supplementation. The mean erythrocyte omega-3 index, which did not differ between the groups at baseline (control 4·2 (sem 0·2), n 13; FO 4·7 (sem 0·2), n 13), remained unchanged in the control group (3·9 (sem 0·2)), but increased in the FO group (6·3 (sem 0·3); P< 0·01). The mean HR during supine resting conditions (control 56 (sem 10); FO 59 (sem 9)) was not affected by FO supplementation. Poincaré analysis of HR variability at rest exhibited a decreasing trend in parasympathetic activity in the FO group (SD1 (standard deviation of points perpendicular to the axis of line of identity)/SD2 (standard deviation of points along the axis of line of identity): control 0·02 (sem 0·01); FO − 0·05 (sem 0·02); P= 0·18). Peak HR was not affected by supplementation. However, during submaximal exercise over 5 min, fewer total heart beats were recorded in the FO group ( − 22 (sem 6) ( = − 4·5 beats/min)), but not in the control group (+1 (sem 4)) (P< 0·05). Supine HR recovery (half-time) after cycling was significantly faster after FO supplementation (control − 0·4 (sem 1·2) s; FO − 8·0 (sem 1·7) s; P< 0·05). A low intake of FO increased the omega-3 index and reduced the mean exercise HR and improved HR recovery without compromising the peak HR. A direct influence of DHA via reductions in the cardiac intrinsic beat rate was balanced by a reciprocal decrease in vagal tone. [ABSTRACT FROM PUBLISHER]

Background: To build research capacity among graduating medical students, the teaching of research and critical analysis was integrated into the University of Wollongong (UoW) new, graduate-entry medical curriculum. This studyexamined whether the self-perceived research experiences of medical students, and consequent research capability, were influenced by exposure to this innovative research and critical analysis curriculum, which incorporated a 12-month community-based research project, and associated assessment tasks. Methods: The first three medical students cohorts (N = 221) completed a self-assessment of their research experiences in ten areas of research activity. Their responses were collected: before and after they undertook an individual community-based research project within a 12-month regional/rural clinical placement. The research areas investigated by the self-assessment tool were: (i) defining a research question/idea; (ii) writing a research protocol; (iii) finding relevant literature; (iv) critically reviewing the literature; (v) using quantitative research methods; (vi) using qualitative research methods; (vii) analysing and interpreting results; (viii) writing and presenting a research report; (ix) publishing results; and (x) applying for research funding. Results: Participation rates of 94% (207/221) pre-placement and 99% (219/221) post-placement were achieved from the three student cohorts. Following the successful completion of the research projects and their assessment tasks, the median responses were significantly higher (p < 0.05) in nine of the ten research areas. The only area of research for which there was no increase recorded for any one of the three cohorts, or overall, was (x) applying for research funding. This activity was not a component of the UoW research and critical analysis curriculum and the item was included as a test of internal validity. Significant gains were also seen between cohorts in some key research areas. Conclusions: Improved research capability among medical students was evidenced by increased scores in various areas of research experience in the context of successful completion of relevant assessment tasks. The results suggest that research capability of medical students can be positively influenced by the provision of a research-based integrated medical curriculum and further consolidated by authentic learning experiences, gained through conducting 'hands-on' research projects, under the supervision and mentoring of research-qualified academics. [ABSTRACT FROM AUTHOR]

Dietary fish oil modifies skeletal muscle membrane fatty acid composition and oxygen efficiency similar to changes in the myocardium. Oxygen efficiency is a key determinant of sustained force in mammalian skeletal muscle. Therefore, in the present study, we tested the effects of a fish-oil diet on skeletal muscle fatigue under the stress of contraction using the rat in vivo autologous perfused hindlimb model. For 8 weeks, male Wistar rats were fed a diet rich in saturated fat (SF), a diet rich in n-6 PUFA or a diet rich in long-chain (LC) n-3 PUFA DHA derived from fish oil. In anaesthetised, mechanically ventilated rats, with their hindlimbs perfused with arterial blood at a constant flow, the gastrocnemius–plantaris–soleus muscle bundle was stimulated via sciatic nerve (2 Hz, 6–12 V, 0·05 ms) to contract repetitively for 30 min. Rats fed the n-3 PUFA diet developed higher maximum twitch tension than those fed the SF and n-6 PUFA diets (P< 0·05) and sustained twitch tension through more repetitions before the tension declined to 50 % of the maximum twitch tension (P< 0·05). The n-3 PUFA group used less oxygen for tension developed and produced higher venous lactate concentrations with no difference in glycogen utilisation compared with the SF and n-6 PUFA groups. These results further support that incorporation of DHA into skeletal muscle membranes increases the efficiency of oxygen use over a range of contractile force and this is expressed as a higher sustained force and prolonged time to fatigue. [ABSTRACT FROM PUBLISHER]

Objective Oxygen delivery, underpinned by vascular tone, is the principle limiting factor in the study of skeletal muscle physiology, particularly during muscle contraction. The aim of this study was to develop an autologous perfused rat hind limb preparation for the study of skeletal muscle contractile function. Methods Adult Wistar rats were surgically prepared using a by-pass system for pump-controlled arterial blood flow to, and venous return from the hind limb during periods of quiescence and twitch contraction of the gastrocnemius-plantaris-soleus muscle bundle. Results During rest, hind limb perfusion pressure (102 ± 5 mmHg) was not different to systemic arterial pressure (99 ± 4 mmHg). Hind limb pressure was responsive to vasoconstrictors and vasodilators (±50 mmHg). The arterial PO2 (100 ± 3 mmHg), O2 saturation, and acid-base balance (pH: 7.42 ± 0.01) contributed to resting hind limb ( a-v)O2 difference (4.8 ± 0.5 mL/100 mL) and VO2 (0.31 ± 0.03 μmol/g/min wet weight). Repetitive isometric twitch tension (1 Hz, 0.05 ms, 10 minutes) was best maintained at a flow rate of 2 mL/min ( VO2 increased fivefold during muscle contraction) and efficiency of oxygen use increased from 0.27 ± 0.08-0.52 ± 0.07 N/μmol/min. Conclusion The autologous rat hind limb provided resting vascular tone allowing maintenance of perfusion pressure at flows within the physiological range. Oxygen delivery supported repetitive twitch contractions and facilitated measurement of active metabolism. [ABSTRACT FROM AUTHOR]

Regular fish or fish oil intake is associated with a low incidence of heart failure clinically, and fish oil-induced reduction in cardiac remodelling seen in hypertrophy models may contribute. We investigated whether improved cardiac energy efficiency in non-hypertrophied hearts translates into attenuation of cardiac dysfunction in hypertrophied hearts. Male Wistar rats (n 33) at 8 weeks of age were sham-operated or subjected to abdominal aortic stenosis to produce pressure-overload cardiac hypertrophy. Starting 3 weeks post-operatively to follow initiation of hypertrophy, rats were fed a diet containing 10 % olive oil (control) or 5 % fish oil (ROPUFA® 30 (17 % EPA, 10 % DHA))+5 % olive oil (FO diet). At 15 weeks post-operatively, ventricular haemodynamics and oxygen consumption were evaluated in the blood-perfused, isolated working heart. Resting and maximally stimulated cardiac output and external work were >60 % depressed in hypertrophied control hearts but this was prevented by FO feeding, without attenuating hypertrophy. Cardiac energy efficiency was lower in hypertrophy, but greater in FO hearts for any given cardiac mass. Coronary blood flow, restricted in hypertrophied control hearts, increased with increasing work in hypertrophied FO hearts, revealing a significant coronary vasodilator reserve. Pronounced cardiac dysfunction in hypertrophied hearts across low and high workloads, indicative of heart failure, was attenuated by FO feeding in association with membrane incorporation of n-3 PUFA, principally DHA. Dietary fish oil may offer a new approach to balancing the high oxygen demand and haemodynamic requirements of the failing hypertrophied heart independently of attenuating hypertrophy. [ABSTRACT FROM PUBLISHER]

The article reports on the effect of parallel consulting on the quality of consultations in regional general practice. It is stated that there is no loss in consultation quality, as experienced by the patient, when using the parallel consulting model. The recent rise in the number of Australian medical students, combined with the Federal Government rural bonded scholarship programme, has provided impetus to increasing the delivery of medical training to students.

lschemic preconditioning (IPC) and (n-3) PUFA are both cardioprotective. This study compared effects of dietary fish oil, IPC, and their interactions on heart function and injury during myocardial ischemia and reperfusion. Male Wistar rats were fed diets containing 10% wt:wt fat comprising either 7% high-docosahexaenoic acid (DHA( [22:6(n-3)1 tuna fish oil + 3% olive oil L(n-3) PUFA]; 5% sunflower seed oil + 5% olive oil [(n-6) PUFA]; or 7% beef tallow + 3% olive oil [saturated fat (SF)] for 6 wk. In control experiments, isolated perfused hearts were subjected to 30-mm regional ischemia and reperfused for 120 mm. The (PC hearts were subjected to 3 cycles of 5-mm global ischemia before the ischemia and reperfusion. Control (n-3) PUFA hearts had significantly lower heart rate, coronary flow, end diastolic pressure, maximum relaxation rate, and ischemic and reperfusion arrhythmias. In reperfusion, they had greater developed pressure and maximum relaxation rate and smaller infarct 110.9 ± 0.6% ischemic zone, n= 61 than (n-6) PUFA (47.4 ± 0.3%, n= 61 orSF (50.3 ± 0.3%, n= 6). Compared with control, IPC significantly improved heart function and reduced infarct in (n-6( PUFA (11.8 ± 0.4%, n = 6) and SF hearts (13.1 ± 0.1 0/s, n = 61. Heart function and infarct ](n-3) PUFA 9.6 ± 0.1%, n = 6] did not differ among dietary PC groups. Arrhythmias, significantly reduced by IPC in (n-6) PUFA and SF hearts, were significantly lower in (n-3) PUFA (PC hearts. Dietary fish oil induces a form of preconditioning, nutritional preconditioning, limiting ischemic cardiac injury, and myocar- dial infarction and endows cardioprotection as powerful as PC, which provides no additional protection in (n-3) PUFA hearts. [ABSTRACT FROM AUTHOR]

This study examined the effects of different food sources of protein on energy intake, body weight maintenance, and on the responses of plasma leptin, insulin and adiponectin in chronic high-fat diet-induced obese mice. Obesity was induced in 47 mice with a high-fat diet for 20 weeks. They were divided into five diet groups to test the effects of a higher protein proportion (30% energy), achieved at the expense of carbohydrate. For the next eight weeks, four of the groups were fed diets of chow formulated with whey, soy, red meat or milk while the control group continued on their high-fat diet. The results showed that: (i) increasing the protein : carbohydrate ratio (both at 30% energy) in a high-fat diet did not reduce the level of obesity; (ii) the type of protein added, however, did have a significant effect on the level of obesity attained; (iii) whey protein stabilised weight gain the most, had the strongest satiety effects and also stimulated the highest production of adiponectin; and (iv) whey protein also was associated with the lowest insulin values among all proteins tested. Plasma leptin levels were not affected by any of the diets. Dietary fat remains a potent factor in weight management, but the type and amount of protein may also be important through its effects on food intake. In particular, the apparent decreased appetite associated with increased adiponectin in the whey-based high-protein diet may contribute to stabilised body mass in chronic high-fat diet-induced obesity. [ABSTRACT FROM AUTHOR]

Programmed electrical stimulation in anesthetized marmoset monkeys was used to examine relative antiarrhythmic efficacies of dietary n-3 and n-6 polyunsaturated fatty acids (PUFAs) from fish and plant oils. Diets contained 31% of energy (en%) as fat, comprising 15 en% saturated fat and 7 en% PUFAs, obtained by blending sheep fat with sunflower seed (SF/ 550) on fish oil (SF/FO) and a base diet. After 16-wk feeding, ventricular fibrillation (VF) was inducible in 6 of 10 animals on each diet under control conditions. The VF threshold (VFT) was significantly elevated in the SF/FO group (33.3 ± 3.1 mA; n = 6) compared with the SF/SSO group (14.3 ± 4.9 mA; n = 6). VFT, reduced during acute myocardial ischemia with 10 of 10 animals inducible per diet, remained significantly higher with SF/ FO feeding. The SF/FO diet contained 3.8 en% as n-3 PUFAs, which was incorporated as 31% of myocardial membrane fatty acids. Dietary n-3 PUFA reduced vulnerability of normal or ischemic myocardium to anrhythmias in a nonhuman primate. [ABSTRACT FROM AUTHOR]

This study compared monounsaturated oleic acid with n-6 and n-3 polyunsaturated fatty acids (PUFAs) for their ability to modify the vulnerability to cardiac arrhythmias during ischemia or reperfusion in rats. Replacement of saturated animal fat in the diet with oleic acid-rich olive oil did not significantly alter the incidence of ventricular fibrillation or other cardiac arrhythmias. Replacement with either n-6-rich sunflower seed oil or n-3-rich fish oil reduced the incidence and severity of arrhythmias occurring in ischemia. The fish oil significantly reduced reperfusion arrhythmias independently of antecedent ischemic arrhythmias. Fatal ventricular fibrillation was significantly reduced by n-6 (8%: n 25) and n-3 (0%; n = 24) FUFA but not by monounsaturates (36%; n = 25) compared with saturated fat (42%; n = 24). The results suggest that dietary replacement of saturated fats by n-6 and especially n-3 FUFA but not monounsaturated fatty acids can reduce the likelihood of an ischemic event leading to sudden cardiac death. [ABSTRACT FROM AUTHOR]

Objective: The aim was to investigate (1) the relationship between atrial natriuretic factor (ANF) release and the extent of ischaemia-hypoxia, and (2) the potential role of eicosanoids in ANF release during global ischaemia, particularly the cyclo-oxygenase derivatives (prostaglandins) and the lipoxygenase derivatives (leukotrienes). Methods: Using an isolated perfused, spontaneously beating rat heart, global ischaemia was achieved by the reduction of perfusion flow rate relative to basal flow rate. ANF was measured by radioimmunoassay. Results: A decrease in perfusion flow rate by 75-80% to a final value of 2-2.5 ml·min−1·g−1 heart (n=6) caused a gradual but sustained increase of ANF release which reached a plateau after 12 min, attaining a peak value of 89.9(SEM 26.6)% over baseline. A decrease in perfusion flow rate by 55-60% (n=5) also resulted in an increased ANF secretion, with a peak of 125.6(23.2)% over baseline at 14 min. A decrease in perfusion flow rate by 25-30% to a final value of 5-6.75 ml·min−1·g−1 heart (n=4) showed no change in ANF release. The mean basal value of ANF release was 8.23(2.39) ng·min−1·g−1 heart (n=26). In a separate series of experiments using a reduction of 55-60% in perfusion flow rate but with the addition to the perfusion medium of the specific cyclo-oxygenase inhibitor meclofenamate 10 μM (n=5) or the lipoxygenase inhibitor nordihydroguaiaretic acid 10 μM (n=5), no increase in ANF release occurred during the period of global ischaemia. Neither inhibitor affected ANF release during basal perfusion rates (7-9 ml·min−1·g−1 heart). Conclusions: ANF released in response to global ischaemia is likely to be mediated by prostanoids generated via the cyclo-oxygenase pathway and leukotrienes generated via the lipoxygenase pathway. Both pathways may provide important paracrine/autacoid regulatory roles for the protection of the heart during ischaemia by stimulating ANF release, with the subsequent beneficial effects of the peptide on peripheral tissues, ultimately leading to a reduction in load on the heart.Cardiovascular Research 1993;27:000-000 [ABSTRACT FROM PUBLISHER]

Radionuclide angiography was used to examine the influence of dietary fat on cardiac function in the common marmoset monkey (Callithrix jacchus jacchus) under barbiturate anaesthesia. Animals were fed for 6-8 months with a low fat (4.5%) reference diet or the same diet supplemented (12%) with sunflower seed oil or sheep fat. Although there was a tendency towards increased heart rate, left ventricular ejection fraction, peak ejection rate, and peak filling rate in both fat supplemented groups, significant increases in heart rate (+50%), peak ejection rate (+71%), and peak filling rate (+84%) were found with sheep fat supplementation, whereas only the vegetable oil supplement produced a significant improvement in left ventricular ejection fraction (+23%). There were no differences in resting blood pressure, and the main consequence of dietary fat supplementation was a major increase in apparent cardiac oxygen consumption (+58%) with the sheep fat diet, as determined by the pressure-rate index. Infusion of isoprenaline hydrochloride (0.2 μg·kg−1·min−1) increased all indices of cardiac function towards common maxima. There were no differences in either the depth or duration of anaesthesia between dietary groups. It therefore is unlikely that this contributed to any of the observed dietary induced differences in cardiac function. It is suggested that dietary saturated animal fat increased cardiac work and oxygen consumption at rest to the extent that functional reserve to respond to stress was significantly diminished. Feeding a linoleic acid rich polyunsaturated vegetable oil supplement was, however, accompanied by evidence of some improvement in left ventricular ejection fraction. [ABSTRACT FROM PUBLISHER]

We investigated the risk of ischemic stroke and its subtypes when red meat or poultry was substituted with fish. A total of 57,053 participants aged 50–65 years at baseline were included in the Danish Diet, Cancer and Health study. All participants filled in a food-frequency questionnaire at recruitment. Potential ischemic stroke cases were identified by linkage to the Danish National Patient Register, and all cases were validated and subclassified. Substitutions were investigated as 150 g/week of fish for 150 g/week of red meat or of poultry using multivariable Cox proportional hazard regression models. During 13.5 years of follow-up, 1879 participants developed an ischemic stroke. Replacing red meat or poultry with fish was not associated with the rate of total ischemic stroke, but there was a statistically significant lower rate of large artery atherosclerosis when fish replaced processed (hazard ratio (HR): 0.78; 95% confidence interval (CI): 0.67; 0.90) and unprocessed (HR: 0.87; 95% CI: 0.75; 0.99) red meat. A statistically significant higher rate of cardioembolism was found when poultry was replaced by total fish (HR: 1.42; 95% CI: 1.04; 1.93). When fatty fish replaced unprocessed red meat, a statistically significant lower rate of small-vessel occlusion was found (HR: 0.88; 95% CI: 0.77; 0.99). In conclusion, replacing red meat with fish was not associated with risk of total ischemic stroke but was associated with a lower risk of subtypes of ischemic stroke. [ABSTRACT FROM AUTHOR]

Cardio protective actions of n-3 polyunsaturated fatty acids (PUFA) suggest a preconditioning-like effect. We investigated whether modification of membrane composition by dietary fish oil protects the heart during ischemia/reperfusion compared to ischemic preconditioning. Rats were fed diets with fish oil (n-3 PUFA), sunflower seed oil (n-6 PUFA) or saturated fat (beef tallow) (SF) for 6 weeks. Isovolumic isolated perfused hearts were reperfused for 120min after 30min regional ischemia, with or without ischemic preconditioning (3x 5min cycles of global ischemia). The n-3 PUFA hearts had lower coronary flow (CF), heart rate (HR) and end diastolic pressure (EDP) at rest. In reperfusion they had less arrhythmia, better developed pressure recovery, and maximum relaxation rate, and HR, CF and EDP stayed lower. Ischemic preconditioning reduced CF, HR and EDP at rest, reduced EDP rise in ischemia and improved developed pressure recovery and reduced arrhythmia. Preconditioning was effective only in SF and n-6 PUFA hearts. Therefore, prefeeding with n-3PUFA provided cardio protection, improving recovery, reducing stunning and arrhythmia while ischemic preconditioning provided similar but no additional protection.' We conclude that dietary fish oil produces a preconditioning-like effect that is not subject to desensitisation with long-term feeding. DHA rich tuna fish oil was a gift Of NuMega Lipids Australia. [ABSTRACT FROM AUTHOR]