No abstract

The viscosity evaluation in Plasma is extremely useful in the clinical evaluation of different diseases. A procedure is presented, based on Protonic Magnetic Resonance, for the evaluation of the dynamic viscosity in Blood Plasma and in hemoglobin solution from the determination of the transverse relaxation time (T 2). To experimentally determine the T 2 value, the impulse series Carr-Purcell-Meiboon-Gill was used in a MARAN DRX console (OXFORD INSTRUMENTS) and a homogeneous magnetic system (B 0 = 0.095T). Values were obtained for the viscosity of the blood plasma and hemoglobin of 1.68 ± 0.12 mPas and 12.78 ± 3.55 mPas respectively, which agreed with the determined, in the same samples, using an Ostwald viscometer (1, 45 ± 0.06 mPas for the plasma and 12.82 ± 3.35 mPas for the dissolution of hemoglobin). The dynamic viscosity of the blood plasma was determined in 236 patients with Multiple Myeloma (2.19 ± 0.58 mPas), 142 with Drepanocytic Anemia (2.20 ± 0.79 mPas) showing statistically significant increases with respect to the characteristic values of the controls (1.68 ± 0.12mPas). Magnetic Relaxation is an option to evaluate plasma viscosity because it minimizes the volume of sample needed and eliminates the need to wash the viscometer between determinations. Magnetic Relaxation can compensate its relative high cost, compared with other Viscosimetry methods, facilitating other determinations of utility in several diseases.

The water transport through Red Blood Cells (RBC) membrane has been previously studied in Sickle Cell Disease (SCD) using oxygenated RBC or under complete deoxygenation. In this work, the water efflux in RBC of sickle cell patients was studied under spontaneous deoxygenation conditions. With that purpose, a magnetic resonance method was used to evaluate the water exchange time (τ e) and the permeability through the erythrocyte membrane (P) measuring the spin-spin relaxation time (T 2) in doped and non-doped RBC. Carr-Purcell-Meiboon-Gill (CPMG) pulse sequence was used to measure T 2 in a magnetic resonance console coupled to one homogeneous magnet system (0.095 T). An increase of the water transport in RBC from sickle cell patients was observed and characterized with a τ e value of 15.2 ± 0.8 ms. The abnormal activation of the P sickle , Gardos, and potassium chloride cotransporter channels starting from deoxygenation, as well as, the possible appearance of new pores due to the increase of the hemoglobin-membrane interaction, are suggested to explain this abnormal transport phenotype. The change of the water volume to surface ratio (V/S) in the sickle cells is also suggested to be considered in P calculation under deoxygenation. The results obtained in this work increase the fundamental knowledge about molecular mechanism involved in SCD and could be useful in the development of new methods for diagnostic and treatment evaluation.