Validation of cardiovascular magnetic resonance assessment of pericardial adipose tissue volume

© 2009 Nelson et al; licensee BioMed Central Ltd.Background Pericardial adipose tissue (PAT) has been shown to be an independent predictor of coronary artery disease. To date its assessment has been restricted to the use of surrogate echocardiographic indices such as measurement of epicardial fat thickness over the right ventricular free wall, which have limitations. Cardiovascular magnetic resonance (CMR) offers the potential to non-invasively assess total PAT, however like other imaging modalities, CMR has not yet been validated for this purpose. Thus, we sought to describe a novel technique for assessing total PAT with validation in an ovine model. Methods 11 merino sheep were studied. A standard clinical series of ventricular short axis CMR images (1.5T Siemens Sonata) were obtained during mechanical ventilation breath-holds. Beginning at the mitral annulus, consecutive end-diastolic ventricular images were used to determine the area and volume of epicardial, paracardial and pericardial adipose tissue. In addition adipose thickness was measured at the right ventricular free wall. Following euthanasia, the paracardial adipose tissue was removed from the ventricle and weighed to allow comparison with corresponding CMR measurements. Results There was a strong correlation between CMR-derived paracardial adipose tissue volume and ex vivo paracardial mass (R2 = 0.89, p < 0.001). In contrast, CMR measurements of corresponding RV free wall paracardial adipose thickness did not correlate with ex vivo paracardial mass (R2 = 0.003, p = 0.878). Conclusion In this ovine model, CMR-derived paracardial adipose tissue volume, but not the corresponding and conventional measure of paracardial adipose thickness over the RV free wall, accurately reflected paracardial adipose tissue mass. This study validates for the first time, the use of clinically utilised CMR sequences for the accurate and reproducible assessment of pericardial adiposity. Furthermore this non-invasive modality does not use ionising radiation and therefore is ideally suited for future studies of PAT and its role in cardiovascular risk prediction and disease in clinical practiceAdam J Nelson, Matthew I Worthley, Peter J Psaltis, Angelo Carbone, Benjamin K Dundon, Rae F Duncan, Cynthia Piantadosi, Dennis H Lau, Prashanthan Sanders, Gary A Wittert and Stephen G Worthle

The effect of testosterone and a nutritional supplement on hospital admissions in under-nourished, older people

Extent: 8p.Background: Weight loss and under-nutrition are relatively common in older people, and are associated with poor outcomes including increased rates of hospital admissions and death. In a pilot study of 49 undernourished older, community dwelling people we found that daily treatment for one year with a combination of testosterone tablets and a nutritional supplement produced a significant reduction in hospitalizations. We propose a larger, multicentre study to explore and hopefully confirm this exciting, potentially important finding (NHMRC project grant number 627178). Methods/Design: One year randomized control trial where subjects are allocated to either oral testosterone undecanoate and high calorie oral nutritional supplement or placebo medication and low calorie oral nutritional supplementation. 200 older community-dwelling, undernourished people [Mini Nutritional Assessment score 7.5% over 3 months)]. Hospital admissions, quality-adjusted life years, functional status, nutritional health, muscle strength, body composition and other variables will be assessed. Discussion: The pilot study showed that combined treatment with an oral testosterone and a supplement drink was well tolerated and safe, and reduced the number of people hospitalised and duration of hospital admissions in undernourished, community dwelling older people. This is an exciting finding, as it identifies a treatment which may be of substantial benefit to many older people in our community. We now propose to conduct a multi-centre study to test these findings in a substantially larger subject group, and to determine the cost effectiveness of this treatment. Trial registration: Australian Clinical Trial Registry: ACTRN 12610000356066Cynthia Piantadosi, Renuka Visvanathan, Vasi Naganathan, Peter Hunter, Ian D. Cameron, Kylie Lange, Jonathan Karnon and Ian M. Chapma

Genome sequencing reveals Zika virus diversity and spread in the Americas

Although the recent Zika virus (ZIKV) epidemic in the Americas and its link to birth defects have attracted a great deal of attention, much remains unknown about ZIKV disease epidemiology and ZIKV evolution, in part owing to a lack of genomic data. Here we address this gap in knowledge by using multiple sequencing approaches to generate 110 ZIKV genomes from clinical and mosquito samples from 10 countries and territories, greatly expanding the observed viral genetic diversity from this outbreak. We analysed the timing and patterns of introductions into distinct geographic regions; our phylogenetic evidence suggests rapid expansion of the outbreak in Brazil and multiple introductions of outbreak strains into Puerto Rico, Honduras, Colombia, other Caribbean islands, and the continental United States. We find that ZIKV circulated undetected in multiple regions for many months before the first locally transmitted cases were confirmed, highlighting the importance of surveillance of viral infections. We identify mutations with possible functional implications for ZIKV biology and pathogenesis, as well as those that might be relevant to the effectiveness of diagnostic tests

Effects of obesity and diet induced weight loss on cardiovascular risk factors, vascular and ventricular structure and function, prostate symptoms and sexual function in obese men.

Obesity is a major epidemic and is increasing in prevalence worldwide. The health problems and consequences of obesity include cardiovascular disease (CVD) risk factors, such as hypertension, hyperlipidemia, glucose intolerance and diabetes mellitus. Each of these abnormalities directly promotes atherosclerosis. More recently, visceral obesity has been shown to be independently associated with abnormalities of both the ventricular and vascular structure and function. The mechanisms by which they occur remain incompletely defined. Cardiovascular magnetic resonance imaging (CMR) offers several advantages for evaluation of cardiac structure and function in the obese. The high accuracy and reproducibility of the technique allows for detection of very small changes in ventricular volumes, mass, ejection fraction, and cardiac output with a relatively small sample size, as compared with echocardiography. In this thesis we investigated whether cardiovascular magnetic resonance imaging can better characterize possible cardiac abnormalities associated with obesity, in the absence of other confounding comorbidities. Obesity is associated with myocardial and vascular function, the extent of reversibility of these abnormalities with rapid acute weight loss remains uncertain. Therefore the first aim of the study was to (i) determine the relationship between obesity and left ventricular structure and function using magnetic resonance imaging, and (ii) the acute effects of rapid diet-induced weight loss on cardiac and vascular function in normal obese and obese diabetic men. Erectile dysfunction is related to cardiovascular risk factors such as obesity by an impairment of endothelial function. Therefore, symptoms of erectile dysfunction are probably to precede cardiovascular disease and events. The second aim of this study was to (i) determine the relationship between obesity and erectile function (EF), sexual desire (SD), lower urinary tract symptoms (LUTS) and quality of life (QOL) measures in obese males, and (ii) determine the effects of rapid diet-induced weight loss on EF, SD, LUTS and QOL measures in normal obese and obese diabetic men. In this group of men, obesity was associated with mild/moderate erectile dysfunction, and significant LUTS, which together with sexual desire improved following rapid diet induced weight loss, but was not directly related to the amount of weight loss or changes in measured metabolic state. Pericardial adipose tissue (PAT) covers 80% of the heart and constitutes 20% of its weight. PAT mass is related to the amount of abdominal fat and the risk of coronary atherosclerosis. Epicardial fat mass may be a sensitive indicator of cardiovascular risk. The third aim of this study was to (i) determine the relationship between obesity and PAT volume and (ii) effectively evaluate the impact of caloric restriction and associated weight reduction on epicardical fat volume via cardiac magnetic resonance imaging (CMR). This is the first study to show a reduction in PAT volume is associated with caloric restriction.Thesis (Ph.D.) - University of Adelaide, School of Medicine, 200

The outcome of patients (pts) with metastatic colorectal cancer (mCRC) based on site of metastases (mets) and the impact of molecular markers and site of primary cancer on metastatic pattern

Abstract No.: 356