56 research outputs found
Effects of a short-term overfeeding with fructose or glucose in healthy young males
Consumption of simple carbohydrates has markedly increased over the past decades, and may be involved in the increased prevalence in metabolic diseases. Whether an increased intake of fructose is specifically related to a dysregulation of glucose and lipid metabolism remains controversial. We therefore compared the effects of hypercaloric diets enriched with fructose (HFrD) or glucose (HGlcD) in healthy men. Eleven subjects were studied in a randomised order after 7d of the following diets: (1) weight maintenance, control diet; (2) HFrD (3·5g fructose/kg fat-free mass (ffm) per d, +35% energy intake); (3) HGlcD (3·5g glucose/kg ffm per d, +35% energy intake). Fasting hepatic glucose output (HGO) was measured with 6,6-2H2-glucose. Intrahepatocellular lipids (IHCL) and intramyocellular lipids (IMCL) were measured by 1H magnetic resonance spectroscopy. Both fructose and glucose increased fasting VLDL-TAG (HFrD: +59%, P<0·05; HGlcD: +31%, P=0·11) and IHCL (HFrD: +52%, P<0·05; HGlcD: +58%, P=0·06). HGO increased after both diets (HFrD: +5%, P<0·05; HGlcD: +5%, P=0·05). No change was observed in fasting glycaemia, insulin and alanine aminotransferase concentrations. IMCL increased significantly only after the HGlcD (HFrD: +24%, NS; HGlcD: +59%, P<0·05). IHCL and VLDL-TAG were not different between hypercaloric HFrD and HGlcD, but were increased compared to values observed with a weight maintenance diet. However, glucose led to a higher increase in IMCL than fructos
Standards of practice in forensic age estimation with CT of the medial clavicular epiphysis-a systematic review.
The AGFAD (Arbeitsgemeinschaft für Forensische Alterdiagnostik, Study Group on Forensic Age Diagnostics) has published several recommendations regarding both technical aspects of computed tomography (CT) of the medial clavicular epiphysis (MCE) and the process of reading and interpreting the CT images for forensic age estimations (FAE). There are, however, no published recommendations regarding CT scan protocols and no dose reference values for CT of the MCE. The objective of this analysis was to assess adherence to AGFAD recommendations among practitioners of FAE and analyse reported dose-relevant CT scan parameters with the objective of helping to establish evidence-based dose reference values for FAE. A systematic literature search was conducted in PubMed and in Google Scholar with specific MeSH terms to identify original research articles on FAE with CT of the MCE from 1997 to 2022. A total of 48 studies were included. Adherence to AGFAD recommendations among practitioners of FAE is high regarding the use of Schmeling main stages (93%), bone window (79%), ≤ 1 mm CT slices (67%), axial/coronal CT images (65%), and Kellinghaus sub-stages (59%). The reporting of CT technique and CT dose-relevant scan parameters is heterogeneous and often incomplete in the current literature. Considering the success achieved by the AGFAD in creating standards of practice of FAE in living subjects, there is potential for the AGFAD to establish standards for radiation protection in FAE as well
The effect of a single 2h bout of aerobic exercise on ectopic lipids in skeletal muscle, liver and the myocardium
Aims/hypothesis: Ectopic lipids are fuel stores in non-adipose tissues (skeletal muscle [intramyocellular lipids; IMCL], liver [intrahepatocellular lipids; IHCL] and heart [intracardiomyocellular lipids; ICCL]). IMCL can be depleted by physical activity. Preliminary data suggest that aerobic exercise increases IHCL. Data on exercise-induced changes on ICCL is scarce. Increased IMCL and IHCL have been related to insulin resistance in skeletal muscles and liver, whereas this has not been documented in the heart. The aim of this study was to assess the acute effect of aerobic exercise on the flexibility of IMCL, IHCL and ICCL in insulin-sensitive participants in relation to fat availability, insulin sensitivity and exercise capacity. Methods: Healthy physically active men were included. V ⋅ O 2 max was assessed by spiroergometry and insulin sensitivity was calculated using the HOMA index. Visceral and subcutaneous fat were separately quantified by MRI. Following a standardised dietary fat load over 3days, IMCL, IHCL and ICCL were measured using MR spectroscopy before and after a 2h exercise session at 50-60% of V ⋅ O 2 max . Metabolites were measured during exercise. Results: Ten men (age 28.9 ± 6.4years, mean ± SD; V ⋅ O 2 max 56.3 ± 6.4mlkg−1min−1; BMI 22.75 ± 1.4kg/m2) were recruited. A 2h exercise session resulted in a significant decrease in IMCL (−17 ± 22%, p = 0.008) and ICCL (−17 ± 14%, p = 0.002) and increase in IHCL (42 ± 29%, p = 0.004). No significant correlations were found between the relative changes in ectopic lipids, fat availability, insulin sensitivity, exercise capacity or changes of metabolites during exercise. Conclusions/interpretation: In this group, physical exercise decreased ICCL and IMCL but increased IHCL. Fat availability, insulin sensitivity, exercise capacity and metabolites during exercise are not the only factors affecting ectopic lipids during exercise
A 4-wk high-fructose diet alters lipid metabolism without affecting insulin sensitivity or ectopic lipids in healthy humans
BACKGROUND: High fructose consumption is suspected to be causally linked to the epidemics of obesity and metabolic disorders. In rodents, fructose leads to insulin resistance and ectopic lipid deposition. In humans, the effects of fructose on insulin sensitivity remain debated, whereas its effect on ectopic lipids has never been investigated. OBJECTIVE: We assessed the effect of moderate fructose supplementation on insulin sensitivity (IS) and ectopic lipids in healthy male volunteers (n = 7). DESIGN: IS, intrahepatocellular lipids (IHCL), and intramyocellular lipids (IMCL) were measured before and after 1 and 4 wk of a high-fructose diet containing 1.5 g fructose . kg body wt(-1) . d(-1). Adipose tissue IS was evaluated from nonesterified fatty acid suppression, hepatic IS from suppression of hepatic glucose output (6,6-2H2-glucose), and muscle IS from the whole-body glucose disposal rate during a 2-step hyperinsulinemic euglycemic clamp. IHCL and IMCL were measured by 1H magnetic resonance spectroscopy. RESULTS: Fructose caused significant (P < 0.05) increases in fasting plasma concentrations of triacylglycerol (36%), VLDL-triacylglycerol (72%), lactate (49%), glucose (5.5%), and leptin (48%) without any significant changes in body weight, IHCL, IMCL, or IS. IHCL were negatively correlated with triacylglycerol after 4 wk of the high-fructose diet (r = -0.78, P < 0.05). CONCLUSION: Moderate fructose supplementation over 4 wk increases plasma triacylglycerol and glucose concentrations without causing ectopic lipid deposition or insulin resistance in healthy humans
Cloverleaf Sign in Pelvic Magnetic Resonance Imaging for Deep Infiltrating Endometriosis: Association With Longer Operation Times, Greater Blood Loss, and Higher Rates of Bowel Resection.
OBJECTIVES
The aim of this study was to evaluate the significance of a new imaging sign, the "cloverleaf sign," in diagnosing deep infiltrating endometriosis (DIE) with magnetic resonance imaging (MRI) in concordance to intraoperative findings.
MATERIALS AND METHODS
This retrospective study included 103 patients operated during the January 2016 to June 2018 period with preoperative 1.5 T and 3 T MRI, with or without vaginal and rectal gel filling. Magnetic resonance imaging scans were read blinded to intraoperative findings by a specialized gynecologic radiologist and a junior radiologist, and then compared with intraoperative findings by looking at the operation report, postoperative diagnosis, and intraoperative images and videos by an experienced gynecologist surgeon specialized in endometriosis surgery. All endometriosis lesions were confirmed by pathology. The "cloverleaf sign" was defined as a cloverleaf-like figure in imaging morphology; the "leaves" formed by at least 3 different organs come together in the center of the figure formed by constrictive adhesions including T2-weighted (T2W) hypointense DIE. Operation times, intraoperative blood loss, and the frequency of DIE and bowel resections were analyzed in cloverleaf and noncloverleaf groups. The 2-sample Wilcoxon rank-sum (Mann-Whitney U) test and multivariate analysis of variance were used to calculate the significance of an overall impact of cloverleaf sign on operation time, blood loss, and the amount of the bowel resection rate. P < 0.05 was considered statistically significant.
RESULTS
The prevalence of DIE in the study population was 79.6%. A total of 11.5% of the patients had no endometriosis, 32.6% had rASRM I and II, and 55.9% had rASRM III and IV. Forty-six patients (45%) had received rectal and vaginal gel opacification before scanning, 57 (55%) did not. A cloverleaf sign on MRI was detected in 34 patients (15 in gel filling and 19 in nonfilling group). The interreader agreement was almost perfect 0.91 (κ). The median operation time in the cloverleaf group was 248 minutes (interquartile range [IQR], 165-330) compared with 145 minutes in the noncloverleaf group (IQR, 90-210), that is, significantly higher (P < 0.001). Intraoperative blood loss was also significantly higher in the conglomerate group (125 vs 50 mL; IQR, 100-300 vs 50-100; P < 0.001). Of the bowel resections in our study population, 41% (14/34) were performed on patients with a cloverleaf sign in the MRI, compared with 13% (9/69) in patients without the cloverleaf sign.
CONCLUSIONS
The "cloverleaf" MRI sign was associated with significantly longer operation time, increased intraoperative blood loss, and higher rates of bowel resection in DIE patients
Estimation of the postmortem interval by means of ¹H MRS of decomposing brain tissue: influence of ambient temperature
Standard methods for the estimation of the postmortem interval (PMI, time since death), based on the cooling of the corpse, are limited to about 48 h after death. As an alternative, noninvasive postmortem observation of alterations of brain metabolites by means of (1)H MRS has been suggested for an estimation of the PMI at room temperature, so far without including the effect of other ambient temperatures. In order to study the temperature effect, localized (1)H MRS was used to follow brain decomposition in a sheep brain model at four different temperatures between 4 and 26°C with repeated measurements up to 2100 h postmortem. The simultaneous determination of 25 different biochemical compounds at each measurement allowed the time courses of concentration changes to be followed. A sudden and almost simultaneous change of the concentrations of seven compounds was observed after a time span that decreased exponentially from 700 h at 4°C to 30 h at 26°C ambient temperature. As this represents, most probably, the onset of highly variable bacterial decomposition, and thus defines the upper limit for a reliable PMI estimation, data were analyzed only up to this start of bacterial decomposition. As 13 compounds showed unequivocal, reproducible concentration changes during this period while eight showed a linear increase with a slope that was unambiguously related to ambient temperature. Therefore, a single analytical function with PMI and temperature as variables can describe the time courses of metabolite concentrations. Using the inverse of this function, metabolite concentrations determined from a single MR spectrum can be used, together with known ambient temperatures, to calculate the PMI of a corpse. It is concluded that the effect of ambient temperature can be reliably included in the PMI determination by (1)H MRS
Radial self-navigated native magnetic resonance angiography in comparison to navigator-gated contrast-enhanced MRA of the entire thoracic aorta in an aortic patient collective.
BACKGROUND
The native balanced steady state with free precession (bSSFP) magnetic resonance angiography (MRA) technique has been shown to provide high diagnostic image quality for thoracic aortic disease. This study compares a 3D radial respiratory self-navigated native MRA (native-SN-MRA) based on a bSSFP sequence with conventional Cartesian, 3D, contrast-enhanced MRA (CE-MRA) with navigator-gated respiration control for image quality of the entire thoracic aorta.
METHODS
Thirty-one aortic native-SN-MRA were compared retrospectively (63.9 ± 10.3 years) to 61 CE-MRA (63.1 ± 11.7 years) serving as a reference standard. Image quality was evaluated at the aortic root/ascending aorta, aortic arch and descending aorta. Scan time was recorded. In 10 patients with both MRA sequences, aortic pathologies were evaluated and normal and pathologic aortic diameters were measured. The influence of artifacts on image quality was analyzed.
RESULTS
Compared to the overall image quality of CE-MRA, the overall image quality of native-SN-MRA was superior for all segments analyzed (aortic root/ascending, p < 0.001; arch, p < 0.001, and descending, p = 0.005). Regarding artifacts, the image quality of native-SN-MRA remained superior at the aortic root/ascending aorta and aortic arch before and after correction for confounders of surgical material (i.e., susceptibility-related artifacts) (p = 0.008 both) suggesting a benefit in terms of motion artifacts. Native-SN-MRA showed a trend towards superior intraindividual image quality, but without statistical significance. Intraindividually, the sensitivity and specificity for the detection of aortic disease were 100% for native-SN-MRA. Aortic diameters did not show a significant difference (p = 0.899). The scan time of the native-SN-MRA was significantly reduced, with a mean of 05:56 ± 01:32 min vs. 08:51 ± 02:57 min in the CE-MRA (p < 0.001).
CONCLUSIONS
Superior image quality of the entire thoracic aorta, also regarding artifacts, can be achieved with native-SN-MRA, especially in motion prone segments, in addition to a shorter acquisition time
Selection for biopsy of kidney transplant patients by diffusion-weighted MRI.
OBJECTIVES
To assess retrospectively whether diffusion-weighted magnetic resonance imaging (DW-MRI) allows physicians to determine the severity of histopathologic findings in biopsies of renal allograft patients with deteriorating renal function.
METHODS
Forty consecutive kidney transplant patients underwent DW-MRI and biopsy. Patients were assigned to one group with severe and to another group with normal or mild histopathologic findings. These two groups were compared based on a qualitative DW-MRI assessment (homo-/heterogeneity) and the combination of qualitative and quantitative DW-MRI parameters (ADC, and intravoxel incoherent motion, IVIM, parameters: D, f, D*). Sensitivity, specificity, and accuracy were determined for each parameter.
RESULTS
Biopsy findings were severe in 25 patients and normal or mild in 15 patients. Qualitative DW-MRI led to a sensitivity of 44.0% and a specificity of 93.3%. Combined qualitative and quantitative DW-MRI led to an accuracy of 80% for both the minimal ADC (ADCmin) and the minimal perfusion fraction (fmin) with a sensitivity of 84.0% and 92.0% and a specificity of 73.3% and 60.0%, respectively.
CONCLUSION
Combined qualitative and quantitative DW-MRI might allow physicians to determine the severity of histopathologic findings in biopsies of a high number of kidney transplant patients.
KEY POINTS
• Qualitative DW-MRI is highly specific when predicting the severity of kidney transplant biopsy. • Allografts appearing heterogeneous on ADC are associated with severe histopathologic findings. • Combining qualitative and quantitative DW-MRI parameters improves the classification's sensitivity and accuracy. • Kidney transplant biopsies might be spared by combining qualitative and quantitative DW-MRI
Cardiac lipid levels show diurnal changes and long-term variations in healthy human subjects
(1) H-MRS is regularly applied to determine lipid content in ectopic tissue - mostly skeletal muscle and liver - to investigate physiological and/or pathologic conditions, e.g. insulin resistance. Technical developments also allow non-invasive in vivo assessment of cardiac lipids; however, basic data about methodological reliability (repeatability) and physiological variations are scarce. The aim of the presented work was to determine potential diurnal changes of cardiac lipid stores in humans, and to put the results in relation to methodological repeatability and normal physiological day-to-day variations. Optimized cardiac- and respiratory-gated (1) H-MRS was used for non-invasive quantification of intracardiomyocellular lipids (ICCL), creatine, trimethyl-ammonium compounds (TMA), and taurine in nine healthy young men at three time points per day on two days separated by one week. This design allowed determination of (a) diurnal changes, (b) physiological variation over one week and (c) methodological repeatability of the ICCL levels. Comparison of fasted morning to post-absorptive evening measurements revealed a significant 37 ± 19% decrease of ICCL during the day (p = 0.0001). There was a significant linear correlation between ICCL levels in the morning and their decrease during the day (p = 0.015). Methodological repeatability for the ICCL/creatine ratio was excellent, with a coefficient of variance of ~5%, whereas physiological variation was found to be considerably higher (22%) in spite of a standardized physiological preparation protocol. In contrast, TMA levels remained stable over this time period. The proposed (1) H-MRS technique provides a robust way to investigate relevant physiological changes in cardiac metabolites, in particular ICCL. The present results suggest that ICCL reveal a diurnal course, with higher levels in the morning as compared to evening. In addition, a considerable long-term variation of ICCL levels, in both the morning and evening, was documented. Given the high methodological repeatability, these effects should be taken into account in studies investigating the metabolic role of ICCL
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