Who is at low risk for cardiovascular disease? An assessment of different definitions.

BACKGROUND: There is little information regarding the determinants and trends of the prevalence of low cardiovascular risk factor (RF) profile in the general population. The aim of this study was to assess the prevalence and trends of low RF profile in the Swiss population according to different definitions. METHODS: Population-based cross-sectional studies conducted in 1984-1986 (N=3300), 1988-1989 (N=3331), 1992-1993 (N=3133) and 2003-2006 (N=6170) and restricted to age group 35-75 years. Seven different definitions of low RF profile were used to assess determinants, while two definitions were used to assess trends. RESULTS: Prevalence of low RF profile varied between 6.5% (95% confidence interval: 5.9-7.1) and 9.7% (9.0-10.5) depending on the definition used. This prevalence was higher than in other countries. Irrespective of the definition used, the prevalence of low RF profile was higher in women and in physically active participants, and decreased with increasing age or in the presence of a family history of cardiovascular disease. Using one definition, the prevalence of low RF profile increased from 3.8% (3.1-4.5) in 1984-1986 to 6.7% (6.1-7.3) in 2003-2006; using another definition, the results were 5.9% (5.1-6.8) and 9.7% (9.0-10.5), respectively. CONCLUSION: Switzerland is characterized by a high and increasing prevalence of low RF profile within the age group 35 to 75, irrespective of the criteria used. This high prevalence might partly explain the low and decreasing trend in cardiovascular mortality rates.

Simultaneous EEG-fMRI at ultra-high field: Artifact prevention and safety assessment.

The simultaneous recording of scalp electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) can provide unique insights into the dynamics of human brain function, and the increased functional sensitivity offered by ultra-high field fMRI opens exciting perspectives for the future of this multimodal approach. However, simultaneous recordings are susceptible to various types of artifacts, many of which scale with magnetic field strength and can seriously compromise both EEG and fMRI data quality in recordings above 3T. The aim of the present study was to implement and characterize an optimized setup for simultaneous EEG-fMRI in humans at 7T. The effects of EEG cable length and geometry for signal transmission between the cap and amplifiers were assessed in a phantom model, with specific attention to noise contributions from the MR scanner coldheads. Cable shortening (down to 12cm from cap to amplifiers) and bundling effectively reduced environment noise by up to 84% in average power and 91% in inter-channel power variability. Subject safety was assessed and confirmed via numerical simulations of RF power distribution and temperature measurements on a phantom model, building on the limited existing literature at ultra-high field. MRI data degradation effects due to the EEG system were characterized via B0 and B1(+) field mapping on a human volunteer, demonstrating important, although not prohibitive, B1 disruption effects. With the optimized setup, simultaneous EEG-fMRI acquisitions were performed on 5 healthy volunteers undergoing two visual paradigms: an eyes-open/eyes-closed task, and a visual evoked potential (VEP) paradigm using reversing-checkerboard stimulation. EEG data exhibited clear occipital alpha modulation and average VEPs, respectively, with concomitant BOLD signal changes. On a single-trial level, alpha power variations could be observed with relative confidence on all trials; VEP detection was more limited, although statistically significant responses could be detected in more than 50% of trials for every subject. Overall, we conclude that the proposed setup is well suited for simultaneous EEG-fMRI at 7T.

New trends in the kitchen: propellants assessment of edible food aerosol sprays used on food.

New products available for food creations include a wide variety of "supposed" food grade aerosol sprays. However, the gas propellants used cannot be considered as safe. The different legislations available did not rule any maximum residue limits, even though these compounds have some limits when used for other food purposes. This study shows a preliminary monitoring of propane, butane and dimethyl ether residues, in cakes and chocolate after spraying, when these gases are used as propellants in food aerosol sprays. Release kinetics of propane, butane and dimethyl ether were measured over one day with sprayed food, left at room temperature or in the fridge after spraying. The alkanes and dimethyl ether analyses were performed by headspace-gas chromatography-mass spectrometry/thermal conductivity detection, using monodeuterated propane and butane generated in situ as internal standards. According to the obtained results and regardingthe extrapolations of the maximum residue limits existing for these substances, different delays should be respected according to the storage conditions and the gas propellant to consume safely the sprayed food.

Diffusion-weighted magnetic resonance imaging in metastatic gastrointestinal stromal tumor (GIST): a pilot study on the assessment of treatment response in comparison with 18F-FDG PET/CT.

BACKGROUND: Diffusion-weighted magnetic resonance imaging (MRI) is increasingly being used for assessing the treatment succes in oncology, but the real clinical value needs to evaluated by comparison with other, already established, metabolic imaging techniques. PURPOSE: To prospectively evaluate the clinical potential of diffusion-weighted MRI with apparent diffusion coefficient (ADC) mapping for gastrointestinal stromal tumor (GIST) response to targeted therapy compared with 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT). MATERIAL AND METHODS: Eight patients (mean age, 56 ± 11 years) known to have metastatic GIST underwent 18F-FDG PET/CT and MRI (T1Gd, DWI [b = 50,300,600], ADC mapping) simultaneously, before and after change in targeted therapy. MR and PET/CT examinations were first analyzed blindly. Second, PET/CT images were co-registered with T1Gd-MR images for lesion detection. Only 18F-FDG avid lesions were considered. Maximum standardized uptake value (SUVmax) and the corresponding minimum ADCmin were measured for the six largest lesions per patient, if any, on baseline and follow-up examinations. The relationship between changes in SUVmax and ADCmin was analyzed (Spearman's correlation). RESULTS: Twenty-four metastases (12 hepatic, 12 extra-hepatic) were compared on PET/CT and MR images. SUVmax decreased from 7.7 ± 8.1 g/mL to 5.5 ± 5.4 g/mL (P = 0.20), while ADCmin increased from 1.2 ± 0.3 × 10(-3)mm(2)/s to 1.5 ± 0.3 × 10(-3)mm(2)/s (P = 0.0002). There was a significant association between changes in SUVmax and ADCmin (rho = - 0.62, P = 0.0014), but not between changes in lesions size (P = 0.40). CONCLUSION: Changes in ADCmin correlated with the response of 18F-FDG avid GIST to targeted therapy. Thus, diffusion-weighted MRI may represent a radiation-free alternative for follow-up treatment for metastatic GIST patients.

Cross-validation of bioelectrical impedance analysis for the assessment of body composition in a representative sample of 6- to 13-year-old children.

BACKGROUND/OBJECTIVES: (1) To cross-validate tetra- (4-BIA) and octopolar (8-BIA) bioelectrical impedance analysis vs dual-energy X-ray absorptiometry (DXA) for the assessment of total and appendicular body composition and (2) to evaluate the accuracy of external 4-BIA algorithms for the prediction of total body composition, in a representative sample of Swiss children. SUBJECTS/METHODS: A representative sample of 333 Swiss children aged 6-13 years from the Kinder-Sportstudie (KISS) (ISRCTN15360785). Whole-body fat-free mass (FFM) and appendicular lean tissue mass were measured with DXA. Body resistance (R) was measured at 50 kHz with 4-BIA and segmental body resistance at 5, 50, 250 and 500 kHz with 8-BIA. The resistance index (RI) was calculated as height(2)/R. Selection of predictors (gender, age, weight, RI4 and RI8) for BIA algorithms was performed using bootstrapped stepwise linear regression on 1000 samples. We calculated 95% confidence intervals (CI) of regression coefficients and measures of model fit using bootstrap analysis. Limits of agreement were used as measures of interchangeability of BIA with DXA. RESULTS: 8-BIA was more accurate than 4-BIA for the assessment of FFM (root mean square error (RMSE)=0.90 (95% CI 0.82-0.98) vs 1.12 kg (1.01-1.24); limits of agreement 1.80 to -1.80 kg vs 2.24 to -2.24 kg). 8-BIA also gave accurate estimates of appendicular body composition, with RMSE < or = 0.10 kg for arms and < or = 0.24 kg for legs. All external 4-BIA algorithms performed poorly with substantial negative proportional bias (r> or = 0.48, P<0.001). CONCLUSIONS: In a representative sample of young Swiss children (1) 8-BIA was superior to 4-BIA for the prediction of FFM, (2) external 4-BIA algorithms gave biased predictions of FFM and (3) 8-BIA was an accurate predictor of segmental body composition.

Assessment of adipose tissue metabolism by means of subcutaneous mircrodialysis in patients with sepsis of circulatory failure

Summary: To evaluate the role of adipose tissue in the metabolic stress response of critically ill patients, the release of glycerol and lactate by subcutaneous adipose tissue was assessed by means of microdialysis in patients with sepsis or circulatory failure and in healthy subjects. Patients with sepsis had lower plasma free fatty acid concentrations and non-significant elevations of plasma glycerol concentrations, but higher adipose-systemic glycerol concentrations gradients than healthy subjects or patients with circulatory failure, indicating a stimulation of subcutaneous adipose lipolysis. They also had a higher lipid oxidation. Lipid metabolism (adipose-systemic glycerol gradients, lipid oxidation) was not altered in patients with circulatory failure. These observations highlight major differences in lipolysis and lipid utilization between patients with sepsis and circulatory failure. Hyperlactataemia was present in both groups of patients, but the adipose-systemic lactate concentration gradient was not increased, indicating that lactate production by adipose tissue was not involved. This speaks against a role of adipose tissue in the development of hyperlactataemia in critically ill patients.

Reproducibility of straylight measurement by C-Quant for assessment of retinal straylight using the compensation comparison method.

BACKGROUND: Straylight gives the appearance of a veil of light thrown over a person's retinal image when there is a strong light source present. We examined the reproducibility of the measurements by C-Quant, and assessed its correlation to characteristics of the eye and subjects' age. PARTICIPANTS AND METHODS: Five repeated straylight measurements were taken using the dominant eye of 45 healthy subjects (age 21-59) with a BCVA of 20/20: 14 emmetropic, 16 myopic, eight hyperopic and seven with astigmatism. We assessed the extent of reproducibility of straylight measures using the intraclass correlation coefficient. RESULTS: The mean straylight value of all measurements was 1.01 (SD 0.23, median 0.97, interquartile range 0.85-1.1). Per 10 years of age, straylight increased in average by 0.10 (95%CI 0.04 to 0.16, p < 0.01]. We found no independent association of refraction (range -5.25 dpt to +2 dpt) on straylight values (0.001; 95%CI -0.022 to 0.024, p = 0.92). Compared to emmetropic subjects, myopia reduced straylight (-.011; -0.024 to 0.02, p = 0.11), whereas higher straylight values (0.09; -0.01 to 0.20, p = 0.09) were observed in subjects with blue irises as compared to dark-colored irises when correcting for age. The intraclass correlation coefficient (ICC) of repeated measurements was 0.83 (95%CI 0.76 to 0.90). CONCLUSIONS: Our study showed that straylight measurements with the C-Quant had a high reproducibility, i.e. a lack of large intra-observer variability, making it appropriate to be applied in long-term follow-up studies assessing the long-term effect of surgical procedures on the quality of vision.