Consumption of low doses of fat prevents the postprandial rise in chylomicron particle concentration and remnant accumulation in healthy normolipidaemic males

Chylomicron particles are continually synthesised and secreted from the intestine even in the absence of ingested fat. It is possible that following consumption of low doses of fat the basal level of chylomicron secretion and subsequent metabolism are sufficient to metabolise this fat without an increase in postprandial chylomicron concentrations. To test this hypothesis, healthy male subjects were randomised to receive, on three separate occasions, meals containing a range of doses of fat (average 8.1–19 g) and effects on postprandial lipaemia and chylomicron concentration were determined. Furthermore, to delineate the effect on lipid-rich v. lipid-poor (remnant) forms lipid levels were also determined in a density <1.006 g/ml fraction. Following consumption of the very low dose of fat the postprandial concentration of chylomicrons was unaltered, whereas following the medium dose postprandial chylomicron concentrations were significantly increased. Interestingly, this increase was only detected in the lipid-rich chylomicron fraction, with postprandial levels of chylomicron remnants remaining unchanged. In conclusion, it appears that consumption of what would be considered low to medium doses of fat are not associated with transient postprandial increases in chylomicron remnants in healthy male subjects

The chronic effects of fish oil with exercise on postprandial lipaemia and chylomicron homeostasis in insulin resistant viscerally obese men

Background: Visceral obesity and insulin resistance are associated with a postprandial accumulation of atherogenic chylomicron remnants that is difficult to modulate with lipid-lowering therapies. Dietary fish oil and exercise are cardioprotective interventions that can significantly modify the metabolism of TAG-rich lipoproteins. In this study, we investigated whether chronic exercise and fish oil act in combination to affect chylomicron metabolism in obese men with moderate insulin resistance. Methods: The single blind study tested the effect of fish oil, exercise and the combined treatments on fasting and postprandial chylomicron metabolism. Twenty nine men with metabolic syndrome were randomly assigned to take fish oil or placebo for four weeks, before undertaking an additional 12 week walking program. At baseline and at the end of each treatment, subjects were tested for concentrations of fasting apo B48, plasma lipids and insulin. Postprandial apo B48 and TAG kinetics were also determined following ingestion of a fat enriched meal. Results: Combining fish oil and exercise resulted in a significant reduction in the fasting apo B48 concentration, concomitant with attenuation of fasting TAG concentrations and the postprandial TAGIAUC response (p < 0.05). Fish oil by itself reduced the postprandial TAG response (p < 0.05) but not postprandial apo B48 kinetics. Individual treatments of fish oil and exercise did not correspond with improvements in fasting plasma TAG and apo B48. Conclusion: Fish oil was shown to independently improve plasma TAG homeostasis but did not resolve hyper-chylomicronaemia. Instead, combining fish oil with chronic exercise reduced the plasma concentration of pro-atherogenic chylomicron remnants; in addition it reduced the fasting and postprandial TAG response in viscerally obese insulin resistant subjects

Speech-evoked ABR: Effects of age and simulated neural temporal jitter

The speech-evoked auditory brainstem response (sABR) provides a measure of encoding complex stimuli in the brainstem, and this study employed the sABR to better understand the role of neural temporal jitter in the response patterns from older adults. In experiment 1, sABR recordings were used to investigate age-related differences in periodicity encoding of the temporal envelope and fine structure components of the response to a /da/speech token. A group of younger and a group of older adults (n = 22 per group) participated. The results demonstrated reduced amplitude of the fundamental frequency and harmonic components in the spectral domain of the recorded response of the older listeners. In experiment 2, a model of neural temporal jitter was employed to simulate in a group of young adults (n = 22) the response patterns measured from older adults. A small group of older adults (n = 7) were also tested under the jitter simulation conditions. In the young adults, the results showed a systematic reduction in the response amplitude of the most robust response components as the degree of applied jitter increased. In contrast, the older adults did not demonstrate significant response reduction when tested under jitter conditions. The overall pattern of results suggests that older adults have reduced neural synchrony for encoding periodic, complex signals at the level of the brainstem, and that this reduced synchrony can be modeled by simulating neural jitter via disruption of the temporal waveform of the stimulus

Transfusion-related acute lung injury : case report and literature review

Blood transfusion is a common procedure that usually goes without complications. However, adverse transfusion reactions should not be overlooked. Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related fatalities and is characterized by the onset of acute respiratory distress in the form of noncardiogenic pulmonary oedema. We hereby report the case of a 28 year old Jamaican lady who developed acute onset dyspnoea, tachycardia and hypoxaemia following transfusion of fresh frozen plasma and red cell concentrates.peer-reviewe

Prior exercise does not affect chylomicron particle number following a mixed meal of moderate fat content

BACKGROUND: A single session of exercise has been reported to reduce fasting and postprandial triacylglycerol concentrations on the subsequent day. It is possible that exercise also reduces chylomicron particle number, which may underlie the observed reduction in postprandial triacylglycerol concentration. In the present study we aimed to determine whether a single session of exercise reduces fasting and postprandial chylomicron particle number on the subsequent day. In a randomised crossover design eight lean and healthy male and female subjects attended two postprandial testing days. On the previous day the subjects either performed 90 minutes of moderate intensity exercise or did not perform any exercise. Fasting blood samples were then collected prior to ingestion of a moderate fat mixed meal (0.44 g fat, 0.94 g carbohydrate, 0.27 g protein/kg body weight), blood was then collected after 1 h, 2 h, 4 h, 6 h, and 8 h. RESULTS: The fasting and postprandial apolipoprotein B48 concentration (marker of chylomicron particle number) was not affected by prior exercise. However exercise reduced fasting triacylglycerol concentration by 16% (P < 0.05) and there was a trend towards a reduction in the total area under the postprandial triacylglycerol curve (23%; P = 0.053). However when corrected for baseline concentration postprandial triacylglycerol concentration was not affected by prior exercise. CONCLUSION: A single session of exercise of moderate intensity and 90 minutes duration reduces fasting triacylglycerol levels, however fasting and postprandial chylomicron particle number was unaffected. Furthermore it appears that previously observed reductions in postprandial triacylglycerol levels following exercise are only mediated following consumption of high, non-physiologically relevant doses of fat

ARDS and systemic sepsis from Actinomycosis related IUCD infection

Six weeks following a reinsertion of a levonorgestrel intrauterine device, this 43 year old lady was admitted with severe abdominal pain. Radiological investigations indicated fluid collection in the rectovaginal area. The differential diagnosis included pelvic inflammatory disease with a possible pyosalpinx. The condition of the patient deteriorated with the patient developing pleural effusions and other pulmonary complications and adult respiratory distress syndrome, despite treatment with antibiotics directed for systemic sepsis. Patient started improving after CT guided aspiration of the pelvic abscess. Further management with antibiotics was administered after blood cultures showed an Actinomycosis infection. This patient presenting with a non-pulmonary cause of sepsis deteriorated rapidly and developed Adult Respiratory Distress syndrome. Although Actinomycosis is detected incidentally on cervical cytology in asymptomatic patients with an intrauterine device, it may present with tiredness, pyrexia and rigors. Removal of intrauterine device should be carried out after a course of antibiotics and followed by an interval of six weeks before reinsertion.peer-reviewe

Aging-Related Changes in Blood-Brain Barrier Integrity and the Effect of Dietary Fat

Background: Disturbances in blood-brain barrier (BBB) integrity contribute to the onset and progression of neurodegenerative diseases including Alzheimer’s disease (AD) and vascular dementia (VaD). Aging is positively associated with AD and VaD risk, but this may reflect comorbidities or the effects of other chronic modulators of vascular function such as diet. Objective: To explore putative synergistic effects of aging with diet, in this study genetically unmanipulated mice were maintained on diets enriched in saturated fatty acids (SFA) or cholesterol and compared to mice provided with low-fat (LF) feed formula. Methods: The functional integrity of the BBB was assessed following 3, 6 and 12 months of dietary intervention commenced at 6 weeks of age, by determining the brain parenchymal extravasation of immunoglobulin G (IgG). Results: Mice maintained on the SFA- or cholesterol-enriched diet showed significant parenchymal IgG abundance following 3 months of feeding, concomitant with diminished expression of the tight junction protein occludin. LF control mice had essentially no evidence of BBB disturbances. Six months of SFA feeding exacerbated the difference in IgG abundance compared to the LF mice. At 12 months of feeding, the control LF mice also had significant parenchymal IgG that was comparable to mice fed the SFA- or cholesterol-enriched diet for 3 months. However, there may have been an adaptation to the fat-enriched diets because SFA and cholesterol did not exacerbate IgG parenchymal accumulation beyond 6 months of feeding. Conclusion: Collectively, the study suggests that diets enriched in SFA or cholesterol accelerate the onset of BBB dysfunction that otherwise occurs with aging

Long-term probucol therapy continues to suppress markers of neurovascular inflammation in a dietary induced model of cerebral capillary dysfunction

Background: Probucol has been shown to prevent cerebral capillary disturbances characterized by blood-to-brain extravasation of plasma derived proteins and neurovascular inflammation in mice maintained on western-styled diets for 12 weeks. However the effect of probucol on capillary integrity in aging models with capillary dysfunction is not known. Methods: Wild-type C57BL6 mice were randomized to a low-fat (LF); saturated-fat (SFA); or SFA + Probucol diet for up to12 months of intervention. Results: Mice fed the LF diet had substantially greater parenchymal abundance of plasma derived IgG and apo B lipoproteins at 12 months, compared to LF mice at 3 months of intervention. Markers of neurovascular inflammation were also greater at 12 months in LF fed mice compared to LF mice at 3 months. The SFA diet exacerbated the aging induced parenchymal abundance of IgG and of apo B lipoproteins and neurovascular inflammation at 12 months. The SFA effects were associated with increased production of intestinal lipoprotein amyloid-ß (Aß). The co-provision of probucol with the SFA completely abolished heightened inflammation at 12 months. Probucol attenuated SFA-induced capillary permeability but had only a modest inhibitory effect on parenchymal retention of apoB lipoproteins. The improvements in markers of inflammation and capillary integrity because of probucol correlated with enterocytic genesis of chylomicron Aß. Conclusion: In this long-term feeding study, probucol profoundly suppressed dietary SFA induced disturbances in capillary integrity but had a more modest effect on age-associated changes

Tailored, iterative, printed dietary feedback is as effective as group education in improving dietary behaviours: results from a randomised control trial in middle-aged adults with cardiovascular risk factors

<p>Abstract</p> <p>Background</p> <p>Tailored nutrition interventions have been shown to be more effective than non-tailored materials in changing dietary behaviours, particularly fat intake and fruit and vegetable intake. But further research examining efficacy of tailored nutrition education in comparison to other nutrition education methods and across a wider range of dietary behaviours is needed. The Stages to Healthy Eating Patterns Study (STEPs) was an intervention study, in middle-aged adults with cardiovascular risk factors, to examine the effectiveness of printed, tailored, iterative dietary feedback delivered by mail in improving short-term dietary behaviour in the areas of saturated fat, fruit, vegetable and grain and cereal intake.</p> <p>Methods</p> <p>STEPs was a 3-month randomised controlled trial with a pre and post-test design. There were three experimental conditions: 1) tailored, iterative, printed dietary feedback (TF) with three instalments mail-delivered over a 3-month period that were re-tailored to most recent assessment of dietary intake, intention to change and assessment of self-adequacy of dietary intake. Tailoring for dietary intake was performed on data from a validated 63-item combination FFQ designed for the purpose 2) small group nutrition education sessions (GE): consisting of two 90-minute dietitian-led small group nutrition education sessions and 3) and a wait-listed control (C) group who completed the dietary measures and socio-demographic questionnaires at baseline and 3-months later. Dietary outcome measures in the areas of saturated fat intake (g), and the intake of fruit (serves), vegetables (serves), grain and cereals as total and wholegrain (serves) were collected using 7-day estimated dietary records. Descriptive statistics, paired t-tests and general linear models adjusted for baseline dietary intake, age and gender were used to examine the effectiveness of different nutrition interventions.</p> <p>Results</p> <p>The TF group reported a significantly greater increase in fruit intake (0.3 serves/d P = 0.031) in comparison to GE and the C group. All three intervention groups showed a reduction in total saturated fat intake. GE also had a within-group increase in mean vegetable intake after 3 months, but this increase was not different from changes in the other groups.</p> <p>Conclusions</p> <p>In this study, printed, tailored, iterative dietary feedback was more effective than small group nutrition education in improving the short-term fruit intake behaviour, and as effective in improving saturated fat intake of middle-aged adults with cardiovascular risk factors. This showed that a low-level dietary intervention could achieve modest dietary behaviour changes that are of public health significance.</p

Electrophysiological Measurement of Binaural Beats: Effects of Primary Tone Frequency and Observer Age

OBJECTIVE: The purpose of this study was to determine the reliability of the electrophysiological binaural beat steady state response as a gauge of temporal fine structure coding, particularly as it relates to the aging auditory system. The hypothesis was that the response would be more robust in a lower, than in a higher, frequency region and in younger, than in older, adults. DESIGN: Two experiments were undertaken. The first measured the 40 Hz binaural beat steady state response elicited by tone pairs in two frequency regions: lower (390 and 430 Hz tone pair) and higher (810 and 850 Hz tone pair). Frequency following responses (FFRs) evoked by the tones were also recorded. Ten young adults with normal hearing participated. The second experiment measured the binaural beat and FFRs in older adults but only in the lower frequency region. Fourteen older adults with relatively normal hearing participated. Response metrics in both experiments included response component signal-to-noise ratio (F statistic) and magnitude-squared coherence. RESULTS: Experiment 1 showed that FFRs were elicited in both frequency regions but were more robust in the lower frequency region. Binaural beat responses elicited by the lower frequency pair of tones showed greater amplitude fluctuation within a participant than the respective FFRs. Experiment 2 showed that older adults exhibited similar FFRs to younger adults, but proportionally fewer older participants showed binaural beat responses. Age differences in onset responses were also observed. CONCLUSIONS: The lower prevalence of the binaural beat response in older adults, despite the presence of FFRs, provides tentative support for the sensitivity of this measure to age-related deficits in temporal processing. However, the lability of the binaural beat response advocates caution in its use as an objective measure of fine structure coding