Magnetic susceptibility anisotropy of myocardium imaged by cardiovascular magnetic resonance reflects the anisotropy of myocardial filament α-helix polypeptide bonds

BACKGROUND: A key component of evaluating myocardial tissue function is the assessment of myofiber organization and structure. Studies suggest that striated muscle fibers are magnetically anisotropic, which, if measurable in the heart, may provide a tool to assess myocardial microstructure and function. METHODS: To determine whether this weak anisotropy is observable and spatially quantifiable with cardiovascular magnetic resonance (CMR), both gradient-echo and diffusion-weighted data were collected from intact mouse heart specimens at 9.4 Tesla. Susceptibility anisotropy was experimentally calculated using a voxelwise analysis of myocardial tissue susceptibility as a function of myofiber angle. A myocardial tissue simulation was developed to evaluate the role of the known diamagnetic anisotropy of the peptide bond in the observed susceptibility contrast. RESULTS: The CMR data revealed that myocardial tissue fibers that were parallel and perpendicular to the magnetic field direction appeared relatively paramagnetic and diamagnetic, respectively. A linear relationship was found between the magnetic susceptibility of the myocardial tissue and the squared sine of the myofiber angle with respect to the field direction. The multi-filament model simulation yielded susceptibility anisotropy values that reflected those found in the experimental data, and were consistent that this anisotropy decreased as the echo time increased. CONCLUSIONS: Though other sources of susceptibility anisotropy in myocardium may exist, the arrangement of peptide bonds in the myofilaments is a significant, and likely the most dominant source of susceptibility anisotropy. This anisotropy can be further exploited to probe the integrity and organization of myofibers in both healthy and diseased heart tissue

Antioxidant, free radical scavenging and anti-inflammatory effects of aloesin derivatives in Aloe vera.

The chemical analysis of flesh and pit of two varieties of date palm fruit (Deglet nour and Alig) as well as the radical scavenging activity of their extracts was undertaken. The fruits were grown in Djerid region (Oasis of Tozeur, Tunisia). Total sugars was measured by HPLC method or with Fehling reagent, crude lipid content was obtained by Soxhlet’s extraction, mineral elements were measured by atomic absorption photometer. The antioxidant activity of extracts from the flesh and pit of the date fruit was measured on the basis of the scavenging activity of the stable 1, 1-diphenyl-2-picrylhy-drazyl (DPPH) free radical. Our results showed that the total sugars could present over 60% of the dry weight of date flesh in two studied varieties. The content of reducing sugars was higher in Alig variety than Deglet nour. For the minerals content, dates flesh were a very good source of several minerals and could be an important