| 1. |
- Diaz, Sandra, et al.
(författare)
-
Hyperpolarized (3)He apparent diffusion coefficient MRI of the lung: Reproducibility and volume dependency in healthy volunteers and patients with emphysema.
- 2008
-
Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1522-2586 .- 1053-1807. ; 27, s. 763-770
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To measure the apparent diffusion coefficient (ADC) of hyperpolarized (HP) (3)He gas using diffusion weighted MRI in healthy volunteers and patients with emphysema and examine the reproducibility and volume dependency. MATERIALS AND METHODS: A total of eight healthy volunteers and 16 patients with emphysema were examined after inhalation of HP (3)He gas mixed with nitrogen (N(2)) during breathhold starting from functional residual capacity (FRC) in supine position. Coronal diffusion-sensitized MR images were acquired. Each subject was imaged on three separate days over a seven-day period and received two different volumes (6% and 15% of total lung capacity [TLC]) of HP (3)He each day. ADC maps and histograms were calculated. The mean and standard deviation (SD) of the ADC at different days and volumes were compared. RESULTS: The reproducibility of the mean ADC and SD over several days was good in both healthy volunteers and patients (SD range of 0.003-0.013 cm(2)/second and 0.001-0.009 cm(2)/second at 6% and 15% of TLC for healthy volunteers, and a SD range of 0.001-0.041 cm(2)/second and 0.001-0.011 cm(2)/second, respectively, for patients). A minor but significant increase in mean ADC with increased inhaled gas volume was observed in both groups. CONCLUSION: Mean ADC and SD of HP (3)He MRI is reproducible and discriminates well between healthy controls and patients with emphysema at the higher gas volume. This method is robust and may be useful to gain new insights into the pathophysiology and course of emphysema. J. Magn. Reson. Imaging 2008. (c) 2008 Wiley-Liss, Inc.
|
|
| 2. |
- Diaz, Sandra, et al.
(författare)
-
Validity of apparent diffusion coefficient hyperpolarized He-3-MRI using MSCT and pulmonary function tests as references
- 2009
-
Ingår i: European Journal of Radiology. - : Elsevier BV. - 1872-7727 .- 0720-048X. ; 71:2, s. 257-263
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: To compare apparent diffusion coefficient (ADC) measurements from hyperpolarized (HP) helium (He-3)-magnetic resonance imaging (MRI) with quantitative data from multislice Computed Tomography (CT) (MSCT) of the whole lungs and pulmonary function tests (PFT). Materials and methods: Twenty-seven subjects, 22 with established emphysema and 5 with preclinical emphysema defined by PFT criteria, were examined with Hp He-3-MRI and MSCT. Mean age was 55 (+/- 12) years, 18 female and 9 male. Mean ADC from He-3-MRI was compared with emphysema index (EI), 15th percentile and mean lung density (MLD) values from MSCT. Both mean ADC and MSCT data were compared to PFT, especially percent of predicted diffusing capacity of carbon monoxide (%predicted DLCO), using Pearson's correlation test. Results: Mean ADC and standard deviation values were 0.392 +/- 0.119 cm(2)/s for the established emphysema group and 0.216 +/- 0.046 for the pre-clinical emphysema group. MSCT values for the established emphysema group and pre-clinical emphysema group were: EI (%) 11 +/- 12 and 0.4 +/- 0.6, respectively; 15th percentile (Hounsfield Units (HU)), -956 +/- 25 and -933 +/- 13, respectively and MLD (HU) -877 +/- 20 and -863 +/- 15, respectively. Correlations between mean ADC and El and 15th percentile were both r=0.90 and for MLD r=0.59. There was higher correlation between mean ADC and %predicted DLCO (r=0.90) than between El and %predicted DLCO (r=0.76). Conclusion: Hp He-3-MRI correlates well with density measurements from MSCT and agrees better than MSCT with %predicted DLCO which is the PFT most related to emphysema. (C) 2008 Elsevier Ireland Ltd. All rights reserved.
|
|
| 3. |
- Funk, Eva, 1953-, et al.
(författare)
-
Patient-initiated breath-holds in MRI : an alternative for reducing respiratory artifacts and improving image quality
- 2015
-
Ingår i: Clinical imaging. - : Elsevier. - 0899-7071 .- 1873-4499. ; 39:4, s. 619-622
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: To investigate MRI image quality using two different breath-hold techniques.Materials and methods: Thirty patients remitted for MRI, 2D-dual gradient echo acquisition of the liver conducted two separate breath-hold acquisitions in randomized order, operator-instructed and patient-initiated. The images were reviewed by two radiologists.Results: There were no significant differences in image quality between the two breath-hold techniques either in overall image quality or respiratory motion artifacts. This assessment was equal and concordant for both radiologists.Conclusion: In terms of image quality, the patient self-initiated breath-hold was shown to be an equal alternative to conventional breath-hold imaging.
|
|
| 4. |
- Locke, Adam E, et al.
(författare)
-
Genetic studies of body mass index yield new insights for obesity biology.
- 2015
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 518:7538, s. 197-401
-
Tidskriftsartikel (refereegranskat)abstract
- Obesity is heritable and predisposes to many diseases. To understand the genetic basis of obesity better, here we conduct a genome-wide association study and Metabochip meta-analysis of body mass index (BMI), a measure commonly used to define obesity and assess adiposity, in up to 339,224 individuals. This analysis identifies 97 BMI-associated loci (P < 5 × 10(-8)), 56 of which are novel. Five loci demonstrate clear evidence of several independent association signals, and many loci have significant effects on other metabolic phenotypes. The 97 loci account for ∼2.7% of BMI variation, and genome-wide estimates suggest that common variation accounts for >20% of BMI variation. Pathway analyses provide strong support for a role of the central nervous system in obesity susceptibility and implicate new genes and pathways, including those related to synaptic function, glutamate signalling, insulin secretion/action, energy metabolism, lipid biology and adipogenesis.
|
|
| 5. |
- Sundström, Johan, Professor, 1971-, et al.
(författare)
-
Risk factors for subarachnoid haemorrhage : a nationwide cohort of 950 000 adults
- 2019
-
Ingår i: International Journal of Epidemiology. - : Oxford University Press. - 0300-5771 .- 1464-3685. ; 48:6, s. 2018-2025
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Subarachnoid haemorrhage (SAH) is a devastating disease, with high mortality rate and substantial disability among survivors. Its causes are poorly understood. We aimed to investigate risk factors for SAH using a novel nationwide cohort consortium.METHODS: We obtained individual participant data of 949 683 persons (330 334 women) between 25 and 90 years old, with no history of SAH at baseline, from 21 population-based cohorts. Outcomes were obtained from the Swedish Patient and Causes of Death Registries.RESULTS: During 13 704 959 person-years of follow-up, 2659 cases of first-ever fatal or non-fatal SAH occurred, with an age-standardized incidence rate of 9.0 [95% confidence interval (CI) (7.4-10.6)/100 000 person-years] in men and 13.8 [(11.4-16.2)/100 000 person-years] in women. The incidence rate increased exponentially with higher age. In multivariable-adjusted Poisson models, marked sex interactions for current smoking and body mass index (BMI) were observed. Current smoking conferred a rate ratio (RR) of 2.24 (95% CI 1.95-2.57) in women and 1.62 (1.47-1.79) in men. One standard deviation higher BMI was associated with an RR of 0.86 (0.81-0.92) in women and 1.02 (0.96-1.08) in men. Higher blood pressure and lower education level were also associated with higher risk of SAH.CONCLUSIONS: The risk of SAH is 45% higher in women than in men, with substantial sex differences in risk factor strengths. In particular, a markedly stronger adverse effect of smoking in women may motivate targeted public health initiatives.
|
|
| 6. |
|
|
| 7. |
- Alsharari, Zayed, et al.
(författare)
-
Association between carbohydrate intake and fatty acids in the de novo lipogenic pathway in serum phospholipids and adipose tissue in a population of Swedish men
- 2020
-
Ingår i: European Journal of Nutrition. - : Springer Science and Business Media LLC. - 1436-6207 .- 1436-6215. ; 59:5, s. 2089-2097
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose Fatty acid composition in blood and adipose tissue (AT) is a useful biomarker of dietary fat quality. However, circulating saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) have been proposed to also reflect carbohydrate-induced de novo lipogenesis (DNL) and stearoyl-CoA desaturase (SCD) activity. We aimed to test the hypothesis that high carbohydrate intake is related to SFA and MUFA in serum or AT in a Swedish population. Methods Fatty acid composition was measured in serum phospholipids (PL) and AT by gas chromatography in 63-year-old men (n = 299). Carbohydrate and alcohol intake was assessed (validated 7-day food records) in relation to total SFA, 16:0 (palmitate), 16:1 (palmitoleate), and estimated SCD activity (16:1n-7/16:0-ratio) in serum PL and in AT, respectively. Results Total carbohydrate intake was inversely associated with 16:0 in PL (P = 0.005), independently of BMI. Disaccharides were non-linearly (restricted cubic splines) and weakly associated with 16:1 and SCD activity in PL (nonlinear trend,P <= 0.02) but not AT. Carbohydrate intake and SCD expression were not associated (P >= 0.08,n = 81). Alcohol intake was, however, linearly associated with 16:0 in PL (P < 0.001), and with 16:1 (P < 0.001) and SCD activity (P <= 0.005) in both PL and AT. Conclusions Higher carbohydrate intake from sugar-rich foods or beverages was not clearly reflected by higher SFA or SCD activity in serum PL or AT. Alcohol was, however, associated with higher SFA and MUFA.
|
|
| 8. |
- Alsharari, Zayed, et al.
(författare)
-
Association between carbohydrate intake and fatty acids in the de novo lipogenic pathwayin serum phospholipids and adipose tissue among 63-year old men
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- AbstractBackground: Fatty acid composition in blood and adipose tissue is useful to reflect dietary fatquality, although the utility of even-chain saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) has been debated. Since SFA also can be produced via de novo lipogenesis (DNL), and desaturated to MUFA, it has been proposed that these fatty acids may reflect carbohydrate-induced DNL. We aimed to test the hypothesis that high carbohydrate intake, especially sugars, is related to SFA and MUFA in serum and adipose tissue.Methods: Validated 7-day food records were collected and fatty acid composition in serum phospholipids (PL) and adipose tissue (AT) were measured in 63-year-old men (n=299). Stearoyl-CoA desaturate (SCD) activities in AT and PL were estimated by the palmitoleic acid (16:1) to palmitic acid (16:0) ratio. Associations of dietary carbohydrate, disaccharides, monosaccharides, carbohydrate-to-fiber ratio, and alcohol with the sum of even-chain SFA, 16:0, 16:1, and SCD activity were assessed using linear regression models with and without adjustment for BMI. Non-linear trends were evaluated using restricted cubic splines. In a subsample (n=81) with RNA measured in AT biopsies, associations of dietary carbohydrate and alcohol with SCD gene expression were assessed using linear regression models.Results: In BMI-adjusted models, intake of carbohydrates was inversely associated with palmitic acid in PL (P=0.005). Disaccharide intake was non-linearly associated with 16:1 and SCD activity in PL (P for nonlinear trend ≤0.02), with the lowest values observed in the mid tertile. Alcohol intake was linearly associated with 16:0 in PL (P<0.001) and with 16:1 (P<0.001) and SCD activity (P ≤0.005) in AT. Alcohol intake was non-linear associated (P≤0.02) with 16:1 and SCD activity in PL; with initially stable levels at lower intakes that rapidly increased at intakes above median. In the subsample, we found no associations between carbohydrate intake and SCD gene expression (P ≥0.08).Conclusion: In this Swedish population, we found no evidence to suggest that higher carbohydrate intake or sugar-rich foods or beverages is reflected by higher SFA in PL and AT.Instead, alcohol was consistently associated with higher SFA and MUFA.
|
|
| 9. |
- Alsharari, Zayed, et al.
(författare)
-
CarbohydrateIntake and Abdominal Obesity in Swedish Men
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- ABSTRACTBackground/Objectives: Associations between carbohydrates, particularly simple sugar and starch, and abdominal anthropometric measures appears controversial. However, the role of dietary carbohydrate intake in obesity and abdominal obesity has been debated, and few studies have been conducted in Nordic populations. We aim to examine the associations between carbohydrate quantity and quality, and anthropometric measures in Swedish men.Subjects/Methods: A cross-sectional investigation of 301 63-year-old men was conducted. Six men were excluded due to missing data on dietary intake and anthropometric measures, leaving 295 men for the present study. Healthy men were recruited from the Swedish 60YO cohort of men and women who had a health screening between 1997 to 1999. Carbohydrate and alcohol intake were assessed by a 7-days food record. The examination included anthropometric measurements (e. g., weight, BMI, WC, WHR, and SAD), fasting blood samples, and a comprehensive questionnaire. Spearman rank correlation and linear regression models were performed to assess relations between dietary intakes and anthropometric measures. Intakes of macronutrients were energy-adjusted according to the residual method. Logistic regression models were used to calculate odds ratios (OR) and 95% CI for abdominal obesity per intake tertiles.Results: Intakes of carbohydrate, monosaccharide, fibers, and fruits and vegetables correlated negatively with anthropometric measures of overall obesity (BMI) and AO (WC, WHR, and SAD). Total carbohydrate intake was significantly inversely associated with WHR and SAD. Likewise, monosaccharide intake was significantly associated with lower BMI, WC, WHR, and SAD. In contrast, alcohol intake was significantly associated with weight, BMI, WC, and SAD (Table 4). Alcohol intake was associated with AO (P for linear trend 0.002). Men in the highest tertile of alcohol intake were almost three times as likely to have AO compared to the men in the lowest tertile of intake, OR (95% CI): 2.93 (1.40-6.16). There was no evidence of non-linear association between the macronutrients and AO.Conclusion: In this Swedish population of older men, higher intakes of total carbohydrates and monosaccharides were associated a more favorable body fat distribution and lower abdominal adiposity. Men with higher alcohol intake were more likely to have AO as compared with a lower intake.
|
|
| 10. |
- Alsharari, Zayed, et al.
(författare)
-
Comparison of a 21-item food questionnaire with a 7-day dietary registration andbiomarkers of fat intake in a Swedish cohort of 60-year-old adults.
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- AbstractPurpose. To evaluate a 21-item food frequency questionnaire (FFQ) in men participating in alarge cohort of Swedish 60-year-old adults (60YO).Methods. A self-reported FFQ (including 21 qualitative and semi-quantitative questions) was completed by >2000 men as part of a detailed baseline examination. A subsample of 301 men was included in a subsequent study in which detailed dietary habits were determined by a 7-day food record. Spearman rank correlations (r) and weighted Kappa (Kw) statistics were used to compare food intake categories in FFQ and 7-day food record. Furthermore, fatty acid (FA) composition in serum cholesteryl esters, assessed concurrent with the FFQ completion, was used to evaluate intakes of specific fat-rich foods from the FFQ.Results. We found good agreement between FFQ and food records for the reported intake ofalcohol (r=0.72, Kw=0.51), margarine (r=0.60, Kw=0.33), and fruit (r=0.49, Kw=0.31), reasonably good agreement for total fish (r=0.25, Kw=0.23), and egg (r=0.35, Kw=0.28), but poor agreement for other food groups such as bread, cheese, vegetables and cookies. In addition, serum proportions of long-chain n-3 polyunsaturated FAs and pentadecanoic acid were significantly higher in men with greater intakes of fish and cheese, respectively.Conclusion. In this evaluation of a short FFQ against 7-d food records and serum biomarkers of fat intake we found that the FFQ reasonably well reflected the intake of certain food groups (e.g. alcohol, fish, and margarine), but performed less accurate for other food groups. Firm and overallconclusions on validity are confined by the time-lag between the test and the reference method.
|
|
