Search

Bile exerts multiple functions in the liver and gut and is involved in multiple disease processes. It is secreted continuously from the liver and stored in the gallbladder until needed, and closely reflects the available bile acid pool. The study objective was therefore to develop a reliable MRS protocol and to assess variability of bile acid determination in human gallbladder. MRS measurements were performed on a 3 T MR scanner with 20 subjects to optimize protocols (26 measurements) and conduct a prospective reproducibility study (18 measurements). Measurements were carried out with subjects lying in either supine (23 scans) or prone positions (21 scans) to compare results from the two positions. For reproducibility determination, six of the 20 volunteers (three males, three females, age = 34.9 ± 10.9 years, BMI = 23.4 ± 2.1 kg/m2) were measured three times: back to back to assess technical variability and once again after three weeks to assess total variability, including additional physiological variability. A single voxel was measured in the gallbladder with respiratory triggering. For quantification, apparent T2 times were determined and a non‐water‐suppressed spectrum was acquired. Total bile acids, glycine and taurine conjugated bile acids, and lipids including choline‐containing phospholipids were determined. Higher quality and reliability of gallbladder spectra were obtained with subjects measured in prone compared with supine position. All measurements of the reproducibility sub‐study were of sufficient quality to be included in the analysis. Average coefficients of variation within subjects for the main compounds were 37% for total variation (including physiological and technical variation) and 24% for technical variation alone. These values were much smaller than those between subjects, which were >54% for both back‐to‐back and three weeks separated measurements. These results suggest diagnostic applicability of the method, especially for longitudinal studies aiming at non‐invasive characterization of bile composition in humans with various diseases and/or interventional maneuvers. [ABSTRACT FROM AUTHOR]

The aim of the present study was to establish the developmental profile of metabolic changes of 3D aggregating brain cell cultures by 1H high-resolution magic angle spinning (HR-MAS) NMR spectroscopy. The histotypic 3D brain aggregate, containing all brain cell types, is an excellent model for mechanistic studies including OMICS analysis; however, their metabolic profile has not been yet fully investigated. Chemometric analysis revealed a clear separation of samples from the different maturation time points. Metabolite concentration evolutions could be followed and revealed strong and various metabolic alterations. The strong metabolite evolution emphasizes the brain modeling complexity during maturation, possibly reflecting physiological processes of brain tissue development. The small observed intra- and inter-experimental variabilities show the robustness of the combination of 1H-HR-MAS NMR and 3D brain aggregates, making it useful to investigate mechanisms of toxicity that will ultimately contribute to improve predictive neurotoxicology.ᅟ [ABSTRACT FROM AUTHOR]

The study aim was to unambiguously assign nucleotide sugars, mainly UDP-X that are known to be important in glycosylation processes as sugar donors, and glucose-phosphates that are important intermediate metabolites for storage and transfer of energy directly in spectra of intact cells, as well as in skeletal muscle biopsies by H high-resolution magic-angle-spinning (HR-MAS) NMR. The results demonstrate that sugar phosphates can be determined quickly and non-destructively in cells and biopsies by HR-MAS, which may prove valuable considering the importance of phosphate sugars in cell metabolism for nucleic acid synthesis. As proof of principle, an example of phosphate-sugar reaction and degradation kinetics after unfreezing the sample is shown for a cardiac muscle, suggesting the possibility to follow by HR-MAS NMR some metabolic pathways. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Background and Purpose: In clinical diagnosis, medical image segmentation plays a key role in the analysis of pathological regions. Despite advances in automatic and semi-automatic segmentation techniques, time-effective correction tools are commonly needed to improve segmentation results. Therefore, these tools must provide faster corrections with a lower number of interactions, and a user-independent solution to reduce the time frame between image acquisition and diagnosis. Methods: We present a new interactive method for correcting image segmentations. Our method provides 3D shape corrections through 2D interactions. This approach enables an intuitive and natural corrections of 3D segmentation results. The developed method has been implemented into a software tool and has been evaluated for the task of lumbar muscle and knee joint segmentations from MR images. Results: Experimental results show that full segmentation corrections could be performed within an average correction time of 5.5±3.3 minutes and an average of 56.5±33.1 user interactions, while maintaining the quality of the final segmentation result within an average Dice coefficient of 0.92±0.02 for both anatomies. In addition, for users with different levels of expertise, our method yields a correction time and number of interaction decrease from 38±19.2 minutes to 6.4±4.3 minutes, and 339±157.1 to 67.7±39.6 interactions, respectively. [ABSTRACT FROM AUTHOR]

1H high resolution magic angle spinning (HR-MAS) NMR spectroscopy was applied in combination with multivariate statistical analyses to study the metabolic response of whole cells to the treatment with a hexacationic ruthenium metallaprism [1]6+ as potential anticancer drug. Human ovarian cancer cells (A2780), the corresponding cisplatin resistant cells (A2780cisR), and human embryonic kidney cells (HEK-293) were each incubated for 24 h and 72 h with [1]6+ and compared to untreated cells. Different responses were obtained depending on the cell type and incubation time. Most pronounced changes were found for lipids, choline containing compounds, glutamate and glutathione, nucleotide sugars, lactate, and some amino acids. Possible contributions of these metabolites to physiologic processes are discussed. The time-dependent metabolic response patterns suggest that A2780 cells on one hand and HEK-293 cells and A2780cisR cells on the other hand may follow different cell death pathways and exist in different temporal stages thereof. [ABSTRACT FROM AUTHOR]

The metabolic profiling of tissue biopsies using high-resolution–magic angle spinning (HR-MAS) 1H nuclear magnetic resonance (NMR) spectroscopy may be influenced by experimental factors such as the sampling method. Therefore, we compared the effects of two different sampling methods on the metabolome of brain tissue obtained from the brainstem and thalamus of healthy goats by 1H HR-MAS NMR spectroscopy—in vivo-harvested biopsy by a minimally invasive stereotactic approach compared with postmortem-harvested sample by dissection with a scalpel. Lactate and creatine were elevated, and choline-containing compounds were altered in the postmortem compared to the in vivo-harvested samples, demonstrating rapid changes most likely due to sample ischemia. In addition, in the brainstem samples acetate and inositols, and in the thalamus samples ƴ-aminobutyric acid, were relatively increased postmortem, demonstrating regional differences in tissue degradation. In conclusion, in vivo-harvested brain biopsies show different metabolic alterations compared to postmortem-harvested samples, reflecting less tissue degradation. Sampling method and brain region should be taken into account in the analysis of metabolic profiles. To be as close as possible to the actual situation in the living individual, it is desirable to use brain samples obtained by stereotactic biopsy whenever possible. [ABSTRACT FROM AUTHOR]

The trithiolato bridged diruthenium complex DiRu-1 [(p-MeC6H4iPr)2Ru2(SC6H4-p-But)3]+ is highly cytotoxic against various cancer cell lines, but its exact mode of action remains unknown. The present 1H HR-MAS NMR-based metabolomic study was performed on ovarian cancer cell line A2780, on its cis-Pt resistant variant A2780cisR, and on the cell line HEK-293 treated with 0.03 µM and 0.015 µM of DiRu-1 corresponding to full and half IC50 doses, respectively, to investigate the mode of action of this ruthenium complex. The resulting changes in the metabolic profile of the cell lines were studied using HR-MAS NMR of cell lysates and a subsequent statistical analysis. We show that DiRu-1 in a 0.03 µM dose has significant impact on the levels of a number of metabolites, such as glutamine, glutamate, glutathione, cysteine, lipid, creatine, lactate, and acetate, especially pronounced in the A2780cisR cell line. The IC50/2 dose shows some significant changes, but full IC50 appears to be necessary to observe the full effect. Overall, the metabolic changes observed suggest that redox homeostasis, the Warburg effect, and the lipid metabolism are affected by DiRu-1. [ABSTRACT FROM AUTHOR]

Listeria rhombencephalitis is caused by infection with Listeria monocytogenes and is associated with a high mortality rate in humans and ruminants. Little is known about the metabolic changes associated with neurolisteriosis in particular and infectious central nervous system (CNS) diseases in general. The purpose of our study was to investigate the metabolic changes associated with listeria rhombencephalitis in small ruminants (goats and sheep) as a model for inflammatory CNS disease by 1H high‐resolution magic angle spinning nuclear magnetic resonance (1H HR‐MAS NMR) spectroscopy of brain biopsies obtained from the brainstem and thalamus. Statistical analysis revealed distinct differences in the metabolic profile of brainstem biopsies, the primary location of listeria rhombencephalitis with moderate or severe inflammatory changes. N‐Acetylaspartate (NAA), N‐acetylaspartylglutamate, choline, myo‐inositol and scyllo‐inositol were decreased, and glycine, phosphocholine, taurine and lactate were increased, in the diseased group (n = 13) in comparison with the control group (n = 12). In the thalamus, which showed no or only mild inflammatory changes in the majority of animals, no statistically significant metabolic changes were observed. However, trends for metabolic alterations were partly the same as those found in the brainstem, including NAA, choline and lactate. This may be an indicator of metabolic changes occurring in the early stages of the disease. Therefore, further research with a larger number of animals is needed to evaluate the presence of subtle metabolic changes associated with mild inflammatory changes in the thalamus. In conclusion, 1H HR‐MAS NMR investigation of listeria rhombencephalitis identified brain metabolite changes, offering new insights into the disease pathophysiology. In this metabolomics study, neurolisteriosis was investigated using brain biopsies of goats and sheep, a natural animal model. The partial least squares‐discriminant analysis (PLS‐DA) model discriminated between control and diseased cases in the brainstem, the primary location of the disease. Metabolite alterations are compatible with neuronal necrosis, membrane breakdown and brain edema. In the morphologically unaffected or mildly affected thalamus, no discrimination between control and diseased cases was found, but a trend involving partly the same metabolites as in the brainstem was seen. [ABSTRACT FROM AUTHOR]

Determination of metabolic alterations in apples induced by such processes as different crop protection strategies or storage, are of interest to assess correlations with fruit quality or fruit disorders. Preliminary results proposed the metabolic discrimination of apples from organic (BIO), integrated (IP) and low-input (LI) production. To determine contributions of temporal metabolic developments and to define the type of metabolic changes during storage, 1 H high resolution-magic angle spinning (HR-MAS) NMR spectroscopy of apple pulp was performed before and after two time points of controlled atmosphere storage. Statistical analysis revealed similar metabolic changes over time for IP-, LI- and BIO-samples, mainly decreasing lipid and sucrose, and increasing fructose, glucose and acetaldehyde levels, which are potential contributors to fruit aroma. Across the production systems, BIO apples had consistently higher levels of fructose and monomeric phenolic compounds but lower levels of condensed polyphenols than LI and IP apples, while the remaining metabolites assimilated. [ABSTRACT FROM AUTHOR]