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1.
Environ Monit Assess ; 193(9): 560, 2021 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-34379192

RESUMO

Mining activities in Canada's pristine Arctic (e.g., driving on unpacked roads, blasts, rock grinding, diesel combustion, and garbage incineration) could add local sources of airborne fine particulate matter with a diameter of < 2.5 µm (PM2.5) to their surrounding area. The increase in PM2.5 above the background level around a mine represents a potential disturbance to caribou. To quantify the spatial distribution of the elevated PM2.5, we investigated three different sampling schemes to measure PM2.5 concentration using a portable monitor. We found that the best sampling scheme was to use the regional background PM2.5 as the reference and analyze the anomaly of PM2.5 measured at sites around the mine complex from the background level. The regional background PM2.5 values were measured at the Daring Lake Tundra Research Station during 2018 and 2019. Our results indicated that the background PM2.5 was not a low and constant value but varied with rain events, wind direction, and the impacts of forest fire smoke. After excluding periods affected by forest fires smokes, we found the background PM2.5 was close to 0 µg m-3 for the first few hours after rain, and then increased logistically with the time after rain (tar) to the maximum of 5 (or 10) µg m-3 when the wind came from the north (or south) of the NW-SE axis. The NW-SE axis in western Canada divides the tundra north with few anthropogenic PM2.5 sources from the forested south with many PM2.5 sources from forest fire smokes and human activities. Analyses of PM2.5 anomaly from the background (i.e., PM2.5 measured at a site around the mining complex-the background level at the corresponding tar and wind direction) revealed that the zone of elevated PM2.5 around the mine (Zepm) expanded with tar. In the first few hours after rain, PM2.5 was close to 0 everywhere except within meters of a source (e.g., a truck exhaust) in the downwind direction. During tar = 6 to 96 h, Zepm expanded to 6.3 km in the downwind direction when the wind came from south of the NW-SE axis. A similar result was found in the downwind direction when the wind came from north of the NW-SE axis, with Zepm = 4.4 km. In the upwind direction, the value of Zepm was much smaller, being 0.7 km (or 1.0 km) when the wind came from the north (or south) of the NW-SE axis. For the period of tar between 96 and 192 hours, Zepm further expanded to 21.2 km when the wind from the south of the NW-SE axis. The results from this study indicated that this reference paradigm that uses the regional background PM2.5 as the reference in combination with a portable PM2.5 monitor worked well for quantifying the tempo-spatial patterns of PM2.5 at locations in remote and mostly pristine Arctic. However, their effectiveness for other regions needs further investigation.


Assuntos
Poluentes Atmosféricos , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Humanos , Veículos Automotores , Material Particulado/análise , Emissões de Veículos/análise
2.
Nat Commun ; 12(1): 3442, 2021 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-34117253

RESUMO

Rapid climate warming is altering Arctic and alpine tundra ecosystem structure and function, including shifts in plant phenology. While the advancement of green up and flowering are well-documented, it remains unclear whether all phenophases, particularly those later in the season, will shift in unison or respond divergently to warming. Here, we present the largest synthesis to our knowledge of experimental warming effects on tundra plant phenology from the International Tundra Experiment. We examine the effect of warming on a suite of season-wide plant phenophases. Results challenge the expectation that all phenophases will advance in unison to warming. Instead, we find that experimental warming caused: (1) larger phenological shifts in reproductive versus vegetative phenophases and (2) advanced reproductive phenophases and green up but delayed leaf senescence which translated to a lengthening of the growing season by approximately 3%. Patterns were consistent across sites, plant species and over time. The advancement of reproductive seasons and lengthening of growing seasons may have significant consequences for trophic interactions and ecosystem function across the tundra.


Assuntos
Fenômenos Fisiológicos Vegetais , Plantas , Reprodução/fisiologia , Tundra , Regiões Árticas , Clima , Ecossistema , Flores , Modelos Biológicos , Fenótipo , Plantas/genética , Estações do Ano , Análise Espaço-Temporal , Temperatura
3.
Asia Pac J Clin Nutr ; 29(3): 537-544, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32990613

RESUMO

BACKGROUND AND OBJECTIVES: As the incidence and prevalence of Alzheimer's disease increases, so does the body of epidemiological and clinical research that suggests a relationship between dietary fatty acids, in particular saturates, and cognitive decline. In this study, we investigated the association between serum apolipoprotein B48 (apoB48), saturated fatty acid intake and consumption behaviour, and cognitive performance, in healthy, older aged Australians. METHODS AND STUDY DESIGN: We retrospectively analysed fasted serum apoB48 concentrations, food frequency questionnaire, and cognitive performance data collected from 147 participants (98F|49M) over the age of 50. We used Spearman's correlations and a nested domain model to evaluate the relationship between serum apoB48, dietary behaviour and measures of cognitive performance. RESULTS: Overall, we found that higher fasted apoB48 concentrations, and/or dietary behaviours which led to increased dietary consumption of diets high in saturated fatty acids, were inversely associated with cognition. Interestingly however, dietary behaviour patterns of saturated fatty acid consumption and serum apoB48 were linked with better secondary memory and perceptual speed, respectively. CONCLUSIONS: This is the first time that fasted apoB48 has been implicated as a biomarker for cognitive decline and Alzheimer's disease risk.

4.
Nutr J ; 19(1): 41, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-32398091

RESUMO

BACKGROUND: A diet rich in fruits and vegetables is recommended for cardiovascular health. However, the majority of Australians do not consume the recommended number of vegetable servings each day. Furthermore, intakes of vegetables considered to have the greatest cardiovascular benefit are often very low. Results from prospective observational studies indicate that a higher consumption of cruciferous vegetables (e.g. broccoli, cabbage, cauliflower) is associated with lower cardiovascular disease risk. This may be due to the presence of specific nutrients and bioactive compounds found almost exclusively, or at relatively high levels, in cruciferous vegetables. Therefore, the aim of this randomised controlled crossover trial is to determine whether regular consumption of cruciferous vegetables results in short-term improvement in measures related to cardiovascular disease risk, including ambulatory blood pressure, arterial stiffness, glycaemic control, and circulating biomarkers of oxidative stress and inflammation. METHODS: Twenty-five participants (50-75 years) with mildly elevated blood pressure (systolic blood pressure 120-160 mmHg) will complete two 2-week intervention periods in random order, separated by a 2-week washout period. During the intervention period, participants will consume 4 servings (~ 300 g) of cruciferous vegetables per day as a soup (~ 500-600 mL/day). The 'control' soup will consist of other commonly consumed vegetables (potato, sweet potato, carrot, pumpkin). Both soups will be approximately matched for energy, protein, fat, and carbohydrate content. All measurements will be performed at the beginning and end of each intervention period. DISCUSSION: The findings of this study will provide evidence regarding the potential cardiometabolic health benefits of cruciferous vegetables, which may contribute to the revision of dietary and clinical guidelines. TRIAL REGISTRATION: The trial was registered with the Australian New Zealand Clinical Trial Registry on 19th September 2019 (ACTRN12619001294145).


Assuntos
Brassicaceae , Hipertensão/dietoterapia , Hipertensão/prevenção & controle , Ensaios Clínicos Controlados Aleatórios como Assunto , Verduras , Idoso , Austrália/epidemiologia , Biomarcadores/metabolismo , Pressão Sanguínea , Estudos Cross-Over , Feminino , Controle Glicêmico , Humanos , Masculino , Pessoa de Meia-Idade , Estresse Oxidativo , Rigidez Vascular
5.
Ambio ; 49(3): 786-800, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31332767

RESUMO

Lemmings are a key component of tundra food webs and changes in their dynamics can affect the whole ecosystem. We present a comprehensive overview of lemming monitoring and research activities, and assess recent trends in lemming abundance across the circumpolar Arctic. Since 2000, lemmings have been monitored at 49 sites of which 38 are still active. The sites were not evenly distributed with notably Russia and high Arctic Canada underrepresented. Abundance was monitored at all sites, but methods and levels of precision varied greatly. Other important attributes such as health, genetic diversity and potential drivers of population change, were often not monitored. There was no evidence that lemming populations were decreasing in general, although a negative trend was detected for low arctic populations sympatric with voles. To keep the pace of arctic change, we recommend maintaining long-term programmes while harmonizing methods, improving spatial coverage and integrating an ecosystem perspective.


Assuntos
Arvicolinae , Ecossistema , Animais , Regiões Árticas , Canadá , Dinâmica Populacional , Federação Russa
7.
Med Sci Sports Exerc ; 51(11): 2234-2242, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31145180

RESUMO

INTRODUCTION: Regular exercise can reduce the risk of developing cardiovascular disease through risk factor modification, with high-intensity exercise and more recently small muscle mass training providing alternatives to moderate-intensity exercise. METHODS: This study randomly assigned 53 healthy middle-age adults (age, 62 ± 6 yr) to complete 24 sessions (8 wk; 3 d·wk) of exercise training, using either high-intensity double-leg cycling (n = 17; HITDL), high-intensity single-leg cycling (n = 18; HITSL), or moderate-intensity double-leg cycling (n = 18; MCTDL). Biomarkers of cardiovascular risk (total cholesterol, triglycerides, HDL-c, LDL-c, apo-B48, and glucose), anthropometry measures (body mass, body mass index, waist circumference, and waist-to-hip ratio), resting blood pressure, and aerobic capacity were assessed pre- and postintervention. RESULTS: Total work completed was greater (P < 0.01) in MCTDL (5938 ± 1462 kJ) compared with the HITDL (3462 ± 1063 kJ) and HITSL (4423 ± 1875 kJ). Pre- to posttraining differences were observed for waist-to-hip ratio (0.84 ± 0.09 vs 0.83 ± 0.09; P < 0.01), resting systolic blood pressure (129 ± 11 vs 124 ± 12 mm Hg; P < 0.01), total cholesterol (5.87 ± 1.17 vs 5.55 ± 0.98 mmol·L; P < 0.01), and LDL-c (3.70 ± 1.04 vs 3.44 ± 0.84 mmol·L; P < 0.01), with no differences between conditions. In addition, aerobic capacity increased after training (22.3 ± 6.4 vs 24.9 ± 7.6 mL·kg·min; P < 0.01), with no differences between conditions. CONCLUSION: These findings suggest that all three modes of exercise can be prescribed to achieve cardiovascular risk reduction in an aging population.


Assuntos
Ciclismo/fisiologia , Doenças Cardiovasculares/prevenção & controle , Condicionamento Físico Humano/métodos , Condicionamento Físico Humano/fisiologia , Antropometria , Biomarcadores/sangue , Glicemia/metabolismo , Pressão Sanguínea/fisiologia , Colesterol/sangue , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Receptores de Lipoproteínas/sangue , Fatores de Risco , Triglicerídeos/sangue
9.
Asia Pac J Clin Nutr ; 28(1): 166-176, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30896428

RESUMO

BACKGROUND AND OBJECTIVES: The need for updated competencies for nutrition scientists in Australia was identified. The aim of this paper is to describe the process of revising of these competencies for undergraduate nutrition science degrees in Australia. METHODS AND STUDY DESIGN: An iterative multiple methods approach comprising three stages was undertaken: 1. Scoping study of existing competencies; 2. Exploratory survey; and, 3. Modified Delphi process (2 rounds) involving 128 nutrition experts from industry, community, government and academia. A ≥70% consensus rule was applied to Rounds 1 and 2 of the Delphi process in order to arrive at a final list of competencies. RESULTS: Stage 1: Scoping study resulted in an initial list of 71 competency statements, categorised under six core areas. Stage 2: Exploratory survey-completed by 74 Nutrition Society of Australia (NSA) members; 76% agreed there was a need to update the current competencies. Standards were refined to six core areas and 36 statements. Stage 3: Modified Delphi process-revised competencies comprise five core competency areas, underpinned by fundamental knowledge, skills, attitudes and values: Nutrition Science; Food and the Food System; Nutrition Governance, Sociocultural and Behavioural Factors; Nutrition Research and Critical Analysis; and Communication and Professional Conduct; and three specialist competency areas: Food Science; Public Health Nutrition; and Animal Nutrition. CONCLUSIONS: The revised competencies provide an updated framework of nutrition science knowledge for graduates to effectively practice in Australia. They may be used to benchmark current and future nutrition science degrees and lead to improved employability skills of nutrition science graduates.


Assuntos
Currículo , Ciências da Nutrição/educação , Nutricionistas/educação , Competência Profissional/normas , Austrália , Humanos
10.
Nat Ecol Evol ; 3(1): 45-52, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30532048

RESUMO

Advancing phenology is one of the most visible effects of climate change on plant communities, and has been especially pronounced in temperature-limited tundra ecosystems. However, phenological responses have been shown to differ greatly between species, with some species shifting phenology more than others. We analysed a database of 42,689 tundra plant phenological observations to show that warmer temperatures are leading to a contraction of community-level flowering seasons in tundra ecosystems due to a greater advancement in the flowering times of late-flowering species than early-flowering species. Shorter flowering seasons with a changing climate have the potential to alter trophic interactions in tundra ecosystems. Interestingly, these findings differ from those of warmer ecosystems, where early-flowering species have been found to be more sensitive to temperature change, suggesting that community-level phenological responses to warming can vary greatly between biomes.


Assuntos
Mudança Climática , Flores/crescimento & desenvolvimento , Estações do Ano , Temperatura , Desenvolvimento Vegetal , Tundra
11.
Br J Nutr ; 117(3): 403-412, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-28215212

RESUMO

TAG depleted remnants of postprandial chylomicrons are a risk factor for atherosclerosis. Recent studies have demonstrated that in the fasted state, the majority of chylomicrons are small enough for transcytosis to arterial subendothelial space and accelerate atherogenesis. However, the size distribution of chylomicrons in the absorptive state is unclear. This study explored in normolipidaemic subjects the postprandial distribution of the chylomicron marker, apoB-48, in a TAG-rich lipoprotein plasma fraction (Svedberg flotation rate (Sf>400), in partially hydrolysed remnants (Sf 20-400) and in a TAG-deplete fraction (Sf<20), following ingestion of isoenergetic meals with either palm oil (PO), rice bran or coconut oil. Results from this study show that the majority of fasting chylomicrons are within the potentially pro-atherogenic Sf<20 fraction (70-75 %). Following the ingestion of test meals, chylomicronaemia was also principally distributed within the Sf<20 fraction. However, approximately 40 % of subjects demonstrated exaggerated postprandial lipaemia specifically in response to the SFA-rich PO meal, with a transient shift to more buoyant chylomicron fractions. The latter demonstrates that heterogeneity in the magnitude and duration of hyper-remnantaemia is dependent on both the nature of the meal fatty acids ingested and possible metabolic determinants that influence chylomicron metabolism. The study findings reiterate that fasting plasma TAG is a poor indicator of atherogenic chylomicron remnant homoeostasis and emphasises the merits of considering specifically, chylomicron remnant abundance and kinetics in the context of atherogenic risk. Few studies address the latter, despite the majority of life being spent in the postprandial and absorptive state.


Assuntos
Apolipoproteína B-48/sangue , Aterosclerose/etiologia , Remanescentes de Quilomícrons/sangue , Gorduras na Dieta/administração & dosagem , Metabolismo dos Lipídeos/fisiologia , Período Pós-Prandial , Triglicerídeos/sangue , Adulto , Aterosclerose/sangue , Quilomícrons/sangue , Estudos Cross-Over , Gorduras na Dieta/sangue , Jejum , Feminino , Homeostase , Humanos , Hiperlipidemias/sangue , Hiperlipidemias/etiologia , Masculino , Refeições , Pessoa de Meia-Idade , Óleo de Palmeira , Tamanho da Partícula , Óleos Vegetais/administração & dosagem , Óleos Vegetais/metabolismo , Valores de Referência , Fatores de Risco
12.
Glob Chang Biol ; 23(7): 2660-2671, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28079308

RESUMO

Warmer temperatures are accelerating the phenology of organisms around the world. Temperature sensitivity of phenology might be greater in colder, higher latitude sites than in warmer regions, in part because small changes in temperature constitute greater relative changes in thermal balance at colder sites. To test this hypothesis, we examined up to 20 years of phenology data for 47 tundra plant species at 18 high-latitude sites along a climatic gradient. Across all species, the timing of leaf emergence and flowering was more sensitive to a given increase in summer temperature at colder than warmer high-latitude locations. A similar pattern was seen over time for the flowering phenology of a widespread species, Cassiope tetragona. These are among the first results highlighting differential phenological responses of plants across a climatic gradient and suggest the possibility of convergence in flowering times and therefore an increase in gene flow across latitudes as the climate warms.


Assuntos
Mudança Climática , Desenvolvimento Vegetal , Temperatura , Temperatura Baixa , Estações do Ano , Tundra
13.
Lipids Health Dis ; 15(1): 169, 2016 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-27686975

RESUMO

BACKGROUND: Subjects with metabolic syndrome (MetS) exhibit impaired lipoprotein metabolism and have an increased risk of cardiovascular disease. Although the risk is attributed primarily to the risk associated with individual components, it is also likely affected by other associated metabolic defects. Remnants of postprandial lipoproteins show potent atherogenicity in cell and animal models of insulin resistance and in pre-diabetic subjects with postprandial dyslipidemia. However, few studies have considered regulation of chylomicron remnant homeostasis in MetS per se. This study measured the plasma concentration in Caucasian men and women of small dense chylomicrons following fasting and explored associations with metabolic and anthropometric measures. METHODS: A total of 215 Australian Caucasian participants (median age 62 years) were investigated. Of them, 40 participants were classified as having MetS. Apolipoprotein (apo) B-48, an exclusive marker of chylomicrons, metabolic markers and anthropometric measures were determined following an overnight fast. RESULTS: The fasting apo B-48 concentration was 40 % higher in subjects with MetS than those without MetS. In all subjects, triglyceride (r = 0.445, P < 0.0005), non-HDL cholesterol (r = 0.28, P < 0.0005) and HDL cholesterol concentration (r = -0.272, P < 0.0005) were weakly associated with apo B-48 concentration. In subjects with MetS, the association of apo B-48 with triglyceride and non-HDL cholesterol was enhanced, but neither were robust markers of elevated apo B-48 in MetS (r = 0.618 and r = 0.595 respectively). There was no association between apo B-48 and HDL cholesterol in subjects with MetS. CONCLUSION: This study demonstrates a substantial accumulation of pro-atherogenic remnants in subjects with MetS. We have shown that in a Caucasian cohort, the fasting plasma concentration of triglyceride or HDL/non-HDL cholesterol serves as poor surrogate markers of atherogenic chylomicron remnants. These findings suggest that subjects with MetS exhibit a chronic defect in chylomicron metabolism that is likely to contribute to their increased CV risk.

14.
Atherosclerosis ; 243(1): 236-41, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26407667

RESUMO

AIM: Normocholesterolemic subjects with elevated fasting plasma triglycerides are at increased risk of atherosclerosis through mechanisms that are not yet delineated. We hypothesized that elevated plasma triglyceride is associated with increased vascular exposure to pro-atherogenic lipoprotein remnants. To test this hypothesis, the abundance, and size distribution of chylomicron particles were determined in individuals with and without hypertriglyceridemia. METHODS: Twelve hypertriglyceridemic subjects (HTG group, triglyceride concentration ≥1.7 mmol/L) and twelve normotriglyceridemic subjects (NTG group) matched for age and gender were studied. The distribution of chylomicron particles was assessed by determining the fasting concentration of apo B-48 in serum lipoprotein fractions with Svedberg flotation rates of (Sf) > 400, Sf 20-400 and Sf < 20. RESULTS: The total concentration of apo B-48 in subjects with HTG was almost twice that observed in NTG controls with ∼80% of the increase residing in the Sf < 20 fraction (HTG: 8.7 ± 1.0 µg/mL vs NTG: 5.0 ± 0.6 µg/mL; P = 0.016). Significantly greater concentrations of apo B-48 were also observed in the less dense Sf 20-400 (HTG: 1.1 ± 0.2 µg/mL vs NTG: 0.4 ± 0.07 µg/mL; P < 0.001) and the Sf > 400 (HTG: 1.1 ± 0.3 µg/mL vs NTG: 0.3 ± 0.04 µg/mL; P < 0.001) fractions. An accumulation of triglyceride was also observed across all lipoprotein fractions in HTG subjects compared to NTG (Sf 400 & Sf 20-400: P < 0.001 and Sf < 20: P = 0.013). CONCLUSION: Normocholesterolemic, moderately hypertriglyceridemic subjects are at increased atherogenic risk due to greater apo B-48 concentration in the small, dense lipoprotein fraction.


Assuntos
Quilomícrons/sangue , Hipertrigliceridemia/sangue , Idoso , Antropometria , Apolipoproteína B-100/sangue , Apolipoproteína B-48/sangue , Glicemia/análise , Estudos Transversais , Jejum , Feminino , Humanos , Insulina/sangue , Lipídeos/sangue , Lipoproteínas HDL/sangue , Lipoproteínas VLDL/sangue , Masculino , Pessoa de Meia-Idade , Tamanho da Partícula , Fatores de Risco , Triglicerídeos/sangue
15.
Int J Womens Health ; 6: 259-67, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24648770

RESUMO

PURPOSE: Although elevated cardiovascular disease (CVD) risk factors are associated with a higher risk of developing heart conditions across all ethnic groups, variations exist between groups in the distribution and association of risk factors, and also risk levels. This study assessed the 10-year predicted risk in a multiethnic cohort of women and compared the differences in risk between Asian and Caucasian women. METHODS: Information on demographics, medical conditions and treatment, smoking behavior, dietary behavior, and exercise patterns were collected. Physical measurements were also taken. The 10-year risk was calculated using the Framingham model, SCORE (Systematic COronary Risk Evaluation) risk chart for low risk and high risk regions, the general CVD, and simplified general CVD risk score models in 4,354 females aged 20-69 years with no heart disease, diabetes, or stroke at baseline from the third Australian Risk Factor Prevalence Study. Country of birth was used as a surrogate for ethnicity. Nonparametric statistics were used to compare risk levels between ethnic groups. RESULTS: Asian women generally had lower risk of CVD when compared to Caucasian women. The 10-year predicted risk was, however, similar between Asian and Australian women, for some models. These findings were consistent with Australian CVD prevalence. CONCLUSION: In summary, ethnicity needs to be incorporated into CVD risk assessment. Australian standards used to quantify risk and treat women could be applied to Asians in the interim. The SCORE risk chart for low-risk regions and Framingham risk score model for incidence are recommended. The inclusion of other relevant risk variables such as obesity, poor diet/nutrition, and low levels of physical activity may improve risk estimation.

16.
Lipids Health Dis ; 11: 117, 2012 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-22978403

RESUMO

BACKGROUND: Several studies have identified use of non-steroidal-anti-inflammatory drugs and statins for prevention of dementia, but their efficacy in slowing progression is not well understood. Cerebrovascular disturbances are common pathological feature of Alzheimer's disease. We previously reported chronic ingestion of saturated fatty acids (SFA) compromises blood-brain barrier (BBB) integrity resulting in cerebral extravasation of plasma proteins and inflammation. However, the SFA-induced parenchymal accumulation of plasma proteins could be prevented by co-administration of some cholesterol lowering agents. Restoration of BBB dysfunction is clinically relevant, so the purpose of this study was to explore lipid-lowering agents could reverse BBB disturbances induced by chronic ingestion of SFA's. METHODS: Wild-type mice were fed an SFA diet for 12 weeks to induce BBB dysfunction, and then randomised to receive atorvastatin, pravastatin or ibuprofen in combination with the SFA-rich diet for 2 or 8 weeks. Abundance of plasma-derived immunoglobulin-G (IgG) and amyloid-ß enriched apolipoprotein (apo)-B lipoproteins within brain parenchyme were quantified utilising immunofluorescence microscopy. RESULTS: Atorvastatin treatment for 2 and 8 weeks restored BBB integrity, indicated by a substantial reduction of IgG and apo B, particularly within the hippocampus. Pravastatin, a water-soluble statin was less effective than atorvastatin (lipid-soluble). Statin effects were independent of changes in plasma lipid homeostasis. Ibuprofen, a lipid-soluble cyclooxygenase inhibitor attenuated cerebral accumulation of IgG and apo B as effectively as atorvastatin. Our findings are consistent with the drug effects being independent of plasma lipid homeostasis. CONCLUSION: Our findings suggest that BBB dysfunction induced by chronic ingestion of SFA is reversible with timely introduction and sustained treatment with agents that suppress inflammation.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/fisiopatologia , Dieta Hiperlipídica/efeitos adversos , Hipolipemiantes/farmacologia , Peptídeos beta-Amiloides/sangue , Peptídeos beta-Amiloides/metabolismo , Animais , Apolipoproteínas B/sangue , Apolipoproteínas B/metabolismo , Atorvastatina , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Feminino , Ácidos Heptanoicos/farmacologia , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Ibuprofeno/farmacologia , Imunoglobulina G/sangue , Imunoglobulina G/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Pravastatina/farmacologia , Pirróis/farmacologia
17.
Nutr Metab (Lond) ; 9: 9, 2012 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-22314022

RESUMO

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.

18.
Lipids Health Dis ; 6: 8, 2007 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-17394665

RESUMO

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.


Assuntos
Quilomícrons/sangue , Gorduras na Dieta/administração & dosagem , Exercício Físico/fisiologia , Período Pós-Prandial/fisiologia , Adulto , Apolipoproteína B-48/sangue , Estudos Cross-Over , Carboidratos da Dieta/administração & dosagem , Gorduras na Dieta/sangue , Proteínas na Dieta/administração & dosagem , Jejum/fisiologia , Ácidos Graxos não Esterificados/sangue , Feminino , Homeostase , Humanos , Masculino , Triglicerídeos/sangue
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