Effects of a 5-week intake of erythritol and xylitol on vascular function, abdominal fat and glucose tolerance in humans with obesity: a pilot trial.

Introduction: Previous studies in humans and rats suggest that erythritol might positively affect vascular function, xylitol decrease visceral fat mass and both substances improve glycaemic control. The objective of this study was to investigate the impact of a 5-week intake of erythritol and xylitol on vascular function, abdominal fat and blood lipids, glucose tolerance, uric acid, hepatic enzymes, creatinine, gastrointestinal tolerance and dietary patterns in humans with obesity. Methods: Forty-two participants were randomised to consume either 36 g erythritol, 24 g xylitol, or no substance daily for 5 weeks. Before and after the intervention, arterial stiffness (pulse wave velocity, arteriolar-to-venular diameter ratio), abdominal fat (liver volume, liver fat percentage, visceral and subcutaneous adipose tissue, blood lipids), glucose tolerance (glucose and insulin concentrations), uric acid, hepatic enzymes, creatinine, gastrointestinal tolerance and dietary patterns were assessed. Data were analysed by linear mixed effect model. Results: The 5-week intake of erythritol and xylitol showed no statistically significant effect on vascular function. Neither the time nor the treatment effects were significantly different for pulse wave velocity (time effect: p=0.079, Cohen's D (95% CI) -0.14 (-0.54-0.25); treatment effect: p=0.792, Cohen's D (95% CI) control versus xylitol: -0.11 (-0.61-0.35), control versus erythritol: 0.05 (0.44-0.54), erythritol versus xylitol: 0.07 (-0.41-0.54)). There was no statistically significant effect on abdominal fat, glucose tolerance, uric acid, hepatic enzymes and creatinine. Gastrointestinal tolerance was good except for a few diarrhoea-related symptoms. Participants of all groups reduced their consumption of sweetened beverages and sweets compared with preintervention. Conclusions: The 5-week intake of erythritol and xylitol showed no statistically significant effects on vascular function, abdominal fat, or glucose tolerance in people with obesity. Clinical trial registration: NCT02821923.

Suitability of Magnetic Resonance Imaging for Guided Endodontics: Proof of Principle.

INTRODUCTION: This proof-of-principle study aimed to demonstrate that magnetic resonance imaging (MRI) is sufficiently accurate for the detection of root canals using guided endodontics. METHODS: One hundred extracted human teeth (anterior and premolar) were mounted onto 5 mandibular and 5 maxillary models, fitted with splints designed to accommodate a thin layer of aqueous gel for indirect imaging, and scanned by MRI. After MRI and intraoral scans were aligned using planning software, access cavities were planned virtually, and templates were manufactured with computer-aided design/computer-aided manufacturing, the access cavities were prepared. Cone-beam computed tomographic scans were performed and matched with the virtual preoperative planning data to determine the accuracy of access cavity preparation in terms of deviation between planned and prepared cavities in the mesiodistal and buccolingual dimensions and angle. Descriptive statistical analysis was performed, and the mean values were compared using the t test. RESULTS: Ninety-one of 100 root canals were successfully scouted after MRI-guided access cavity preparation. The mean angle deviation was 1.82°. The mean deviation ranged from 0.21-0.31 mm at the base of the bur and from 0.28-0.44 mm at the tip of the bur. Preparation in the buccolingual dimension was significantly more precise in mandibular compared with maxillary teeth, and accuracy in the mesiodistal dimension was more precise in anterior teeth compared with premolars. CONCLUSIONS: This in vitro study demonstrated the suitability of MRI for guided endodontic access cavity preparation.

Quantification of Liver, Subcutaneous, and Visceral Adipose Tissues by MRI Before and After Bariatric Surgery.

BACKGROUND: Morbid obesity is a worldwide epidemic and is increasingly treated by bariatric surgery. Fatty liver is a common finding; almost half of all patients with non-alcoholic steatohepatitis develop steatohepatitis. Bariatric surgery improves steatohepatitis documented by liver biopsy and single voxel magnetic resonance imaging (MRI) techniques. OBJECTIVE: To investigate changes before and after bariatric surgery using whole organ MRI quantification of liver, visceral, and subcutaneous fat. SETTING: University of Basel Hospital and St. Clara Research Ltd, Basel, Switzerland. METHODS: Sixteen morbidly obese patients were evaluated by abdominal MRI-scanning before and 3, 6, 12, and 24 months after bariatric surgery to measure percentage liver fat (%-LF), total liver volume (TLV) and visceral and subcutaneous adipose tissues (VAT and SAT). Fasting plasma samples were taken for measurement of glucose, insulin, blood lipids, and liver biomarkers. In a control group of 12 healthy lean volunteers, the liver biomarker was also measured. RESULTS: The reproducibility of fat quantification by use of MRI was excellent. LF decreased significantly faster than VAT and SAT (%-LF vs. VAT p < 0.001 and %-LF vs. SAT p < 0.001). At certain time points, %-LF, VAT, and SAT were associated with changes in blood lipids and insulin. CONCLUSIONS: MRI quantification offers excellently reproducible results in measurement of liver fat and visceral and subcutaneous adipose tissues. Liver fat decreased significantly faster than visceral or subcutaneous adipose tissue. Decrease in %-LF and VAT is associated with decrease in total cholesterol, LDL, and plasma insulin.

Assessment of muscle oxygenation with balanced SSFP: a quantitative signal analysis.

PURPOSE: To investigate the feasibility of balanced steady-state free precession (b-SSFP) for blood oxygenation level-dependent (BOLD) MRI during a short-term ischemia/reactive hyperemia (RH) experiment on human calf muscles. MATERIALS AND METHODS: To investigate contributions to the b-SSFP signal during an RH experiment, the relaxation times T(1), T(2), and T(2) (*) were quantified in an interleaved fashion. Data from soleus, gastrocnemius, and tibialis muscle groups of five healthy subjects were evaluated. RESULTS: During ischemia a decreased b-SSFP signal amplitude as well as a decrease in T(2), T(2) (*), and the initial intensity I(0) was observed. RH provoked an overshoot of T(2), T(2) (*), and the b-SSFP signal. No paradigm-related changes in T(1) were observed. Comparing the evolution of transverse relaxation times, initial intensity, and b-SSFP signal amplitude, we concluded that the measured b-SSFP signal in muscle tissue is not only determined by T(2) variations but also significantly influenced by I(0) changes. These I(0) changes are attributed to spin density variations since inflow effects were suppressed by saturation bands. CONCLUSION: b-SSFP signal changes during a RH paradigm cannot unambiguously be assigned to oxygenation changes. Therefore, care has to be taken with their interpretation.