Biochemistry

Perfusion-related changes in intestinal diffusion detected by NMR-MOUSE® monitoring in minipigs

Objective The aim was to investigate perfusion-related changes in the intestinal diffusion assessed by NMR-MOUSE monitoring in minipigs. This was a follow-up study of previous experiments on landrace pigs demonstrating the feasibility of NMR-MOUSE monitoring in large animals. Methods 5 mature female minipigs (mean body weight 50 ± 2 kg) underwent laparotomy with exposition of several small intestinal loops and their feeding vessels. …

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Multicomponent analysis of T1 relaxation in bovine articular cartilage at low magnetic fields

Purpose The multi‐exponential character of T1 relaxation in bovine articular cartilage was investigated at low magnetic fields below 0.5 T. The ultimate aim was to identify a parameter based on the T1 relaxation time distribution as a biomarker to biochemical features of osteoarthritis. Methods Osteoarthritis conditions were simulated by enzymatic digestion of cartilage with trypsin. Fast‐field cycling …

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Transverse Relaxation Based Magnetic Resonance Techniques for Quantitative Assessment of Biological Tissues

Using transverse relaxation based MRI, this thesis has developed new quantitative approaches to characterise the progression of Osteoarthritis in animal models and has introduced this type of characterisation for the assessment of mammographic density. For the first time, it has identified the collagen architecture in the kangaroo knee cartilages using MRI. The three case studies …

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Evaluation of the NMR-MOUSE as a new method for continuous functional monitoring of the small intestine during different perfusion states in a porcine model

Objective: The study aim was to evaluate a small low-field NMR (nuclear magnetic resonance) scanner, the NMR-MOUSE®, for detecting changes in intestinal diffusion under different (patho-) physiological perfusion states. Methods Laparotomy was performed on 8 female landrace pigs (body weight 70±6 kg) and the feeding vessels of several intestinal loops were dissected. Successively, the intestinal …

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T1-based sensing of mammographic density using single-sided portable NMR

Purpose A single‐sided NMR instrument was used to investigate the ability of the T1 relaxation constant to distinguish between regions of low and high mammographic density in human breast tissue. Methods Measurements were performed on 5 breast slices obtained from 3 women undergoing breast reduction surgery or prophylactic mastectomy. Results T1 values measured in regions of high …

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Bone volume-to-total volume ratio measured in trabecular bone by single-sided NMR devices

Purpose Reduced bone strength is associated with a loss of bone mass, usually evaluated by dual‐energy X‐ray absorptiometry, although it is known that the bone microstructure also affects the bone strength. Here, a method is proposed to measure (in laboratory) the bone volume–to–total volume ratio by single‐sided NMR scanners, which is related to the microstructure …

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Load-dependent NMR low-field profiling and relaxation dispersion study of osteoarthritic articular cartilage

At low magnetic fields, T1 variation within cartilage represents a robust parameter that is employed to quantify the layered structure in the tissue and is sensitive to factors such as enzymatic degradation, external load, and degeneration such as osteoarthritis. Variable-field relaxometry, on the other hand, provides access to the quadrupolar dips, i.e. enhanced relaxation rates of 1H …

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Monitoring of Cellular Changes in the Bone Marrow following PTH(1-34) Treatment of OVX Rats Using a Portable Stray-Field NMR Scanner

Osteoporosis is characterized by reduction in trabecular bone in conjunction with increased marrow cell adiposity. While these changes occur within weeks, monitoring of treatment efficacy as performed by DEXA is sensitive only to long-term changes. MRI is sensitive to bone marrow changes but is less affordable. In a recent study, we have shown that a …

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Detection of bone marrow changes related to estrogen withdrawal in rats with a tabletop stray-field NMR scanner

Purpose Osteoporosis is characterized by a decrease in bone mineral density (BMD). A preliminary stage of the disease is progressive bone marrow adiposity, caused by imbalance between osteogenesis and adipogenesis in the marrow. Detection of osteoporosis relies on the quantification of BMD with techniques such as dual‐energy X‐ray absorptiometry. This work aimed to detect bone …

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