[Possible causes of temperature-dependent disorders of regional circulation in cryoglobulinemia].

We studied effects of changed blood theology in cryoglobulinemia on temperature-dependent disorders of peripheral circulation. The rheological status was assessed by aggregation characteristics of blood at temperature 37 degrees C and 4 degrees C at nephelometry of reverse light diffusion. Blood cryoglobulins concentration was determined spectrophotometrically. Turbidimetry estimated the size of cryocomplexes at different temperatures and energetic characteristics of their formation. It was found that blood of healthy donors in cooling does not change its rheological properties significantly. Blood of patients with cryoglobulinemia cooled to 4 degrees accelerated formation of linear erythrocyte aggregates and increased their strength. The results agreed with estimated values of molecular connection energy in cryocomplexes. The greatest difference between the patients' and donors' blood was in strength of the largest aggregates. Sharp strengthening of both large and small aggregates in blood cooling makes vascular red cell desaggregation impossible. This may entail microcirculatory arrest.

The influence of cryoglobulins on the temperature-dependent erythrocyte aggregation in vitro by backscattering nephelometry.

Nephelometry technique was used to register the alterations of the scattering signal from a whole blood sample due to erythrocyte aggregates in stasis and under controlled shear stress. The measured parameters were: the characteristic times of linear and three-dimensional aggregates formation, and the strength of aggregates of different types. These parameters depend on the sample temperature in the range of 2/50 degrees C. Temporal parameters of the aggregation process strongly increase (by 3 times) at temperature 45 degrees C. For samples of normal blood the aggregates strength parameters do not significantly depend on the sample temperature, whereas for blood samples from patients with cryoglobulinemia high increase of the strength of both three-dimensional and linear aggregates and decrease of time of linear aggregates formation at low temperature of the sample (4 degrees C) was observed. The difference of these parameters of the pathological blood from that of the normal at room temperature was quite opposite. Possible reasons of such behavior of aggregation state of blood and explanation of the observed effects are suggested.

Aggregation and disaggregation of erythrocytes in whole blood: study by backscattering technique.

The aggregation phenomenon is of great importance for the evaluation of performance of the microcirculation system because of its influence on the blood viscosity at low shear stresses. Some important features and consequences of this phenomenon in vivo can be predicted in the in vitro experiments using optical methods. These methods are considered to be the most informative and applicable not only for the basic study of the aggregation phenomenon, but also for the diagnosis of a number of diseases and for the monitoring of therapeutic treatment in clinics. Results presented in this paper prove that the backscattering technique allows one to detect different changes of aggregational ability and deformability of erythrocytes and to get reliable and reproducible results distinguishing normal blood and blood with different pathologies. © 1999 Society of Photo-Optical Instrumentation Engineers.