Phosphorus NMR analysis of human white matter in mixed non-ionic detergent micelles.

In order to study the lipid composition of human white matter, we have developed a 31P NMR spectroscopy method, which allows the determination and quantitation of the main phospholipids found in biological membranes. The technique is based upon the use of a non-ionic detergent (Triton X-100) which induces, in aqueous media, the formation of mixed micelles that are magnetically isotropic. The linewidths and chemical shifts depend on both the molar ratio detergent/phospholipid and the pH of the suspension. After determination of the optimum values for these two parameters, 31P NMR spectra were recorded, in which all phospholipid resonances were resolved. After determining precise chemical shifts for each phospholipid, concentrations were measured by comparing the peak areas with that of an internal standard. Analysis of the complex phospholipid composition of human white matter using this method gave values very close to that found in the literature for such tissue. Moreover this nondestructive method proved to be very sensitive since less than 1 mg of a mixture of phospholipids was needed.

[Perspectives in the use of NMR for the biochemical study of the white matter of the brain]. / Perspectives d'emploi de la RMN pour l'étude biochimique de la substance blanche cérébrale.

This paper presents a survey of the function and the biochemical composition of the myelin sheath. Proton nuclear magnetic resonance spectroscopy of extracts of human white matter tissue is a major method for the identification of myelin constituants. We present results of some experiments obtained with normal brain material at 80 MHz and 400 MHz.

Estimating meconium (fetal feces) concentration in human amniotic fluid by nuclear magnetic resonance.

Measurements are reported of NMR relaxation times (T2) on hydrogen in water of isotonic NaCl solutions and of normal human amniotic fluid in which known concentrations of meconium (fetal feces) were dissolved. Magnetic fields for resonance of 23.5 X 10(3) and 0.6 oersteds were used. From the measured T2 values, reliable estimates of meconium concentrations could be obtained that might be considered estimates of fetal distress. Observed minor variation of T2 values was probably due to the mucopolysaccharides comprising 80% of the meconium weight. Advantages of this technique for possible clinical use in obstetrics include small volume of sample required (0.1 ml), lack of necessity for sample filtration or centrifugation, and shortness of time required for analysis (less than 30 min).