A lineshape fitting model was constructed for classifying the overlapping information in the 1H NMR spectrum of human blood plasma. A reliable assignment of the overlapping fatty acid (-CH2-)n and -CH3 resonances of the various lipoproteins (VLDL, very low density lipoprotein; LDL, low density lipoprotein; HDL high density lipoprotein) is introduced, and for the first time detailed characteristics (chemical shifts, half linewidths, and relative intensities) of the individual lipoprotein components were obtained directly from the whole plasma spectrum. This was achieved by combining the constructed lineshape fitting model and the proper 400 MHz proton NMR measurements from blood plasma of a healthy donor, from fractions of the different lipoproteins, and from plasma samples in which the lipoprotein fractions were separately added. The results suggest fair promise of future applications of the rapid and easy NMR analysis of lipoprotein distribution in various research and clinical situations.
To establish which constituents of blood influence the NMR relaxation time T1 of water protons in malignant blood diseases, 55 blood samples were studied (20 from healthy donors and 35 from patients with leukaemia, myelofibrosis and multiple myeloma). Relaxation time measurements were performed at 19.8 MHz resonance frequency and at a temperature of 33 +/- 1 degree C. There is a significant elevation of T1 over the normal level in whole blood, packed cells, and plasma of patients with blood disease. The relaxation rate R1 (= 1/T1) depends very strongly on the ratio of dry solids to water, which is in accordance with the three-state fast-exchange relaxation model.
The purpose of this work was two-fold. In the first instance, 1H NMR spectra of the ultracentrifuged lipoprotein fractions (VLDL, LDL and HDL) from six volunteers with different clinical conditions were measured. The methylene regions of the experimental spectra were modelled in the frequency domain using non-linear lineshape fitting analyses. In this way the resolvable Lorentzian component structures of the methylene regions of these lipoprotein fraction spectra could be determined. Second, the lipoprotein fraction analyses were used to construct simplified component structures, which interpreted the lipoprotein fraction spectra well, and were feasible to use in the total plasma spectra analyses. The considerable overlap problem of the resonances was properly handled in this way. The NMR-based relative amounts of the lipoproteins (relative integrated intensities of the lipoprotein model signals) obtained were compared to the biochemically resolved relative molar percentages of the lipoprotein fractions and also of the lipid contents between the lipoprotein complexes. It was noticed that nearly all correlations were extremely good. Thus, it is suggested that the developed methodology could be used as a fast method to predict the relative amounts of the lipoproteins and also possibly the relative lipid contents between the major lipoprotein categories directly from the proton NMR spectrum of a total blood plasma sample. Furthermore, if internal or external reference for the integrated intensities of the proton NMR resonances were used, it should also be possible to obtain the absolute amounts of these quantities.
The MTFs of three different gamma camera systems have been measured using two methods. In one method a step function was used as the object and the calculations were made by means of a pocket calculator. This method has been compared with a conventional line source method, where a computer is needed in performing the calculations. The methods give the same results with a fairly good accuracy. Both of the methods are well suited to a regular control of the condition and functioning of a gamma camera, provided that the camera is connected to a data-processing system so that the profile curves measured can be converted into the digital form.
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