In the present study electro-rheology (Contraves LS30 viscometer-based system) and optical shearing microscopy (Lincam CSS450 system and image analysis) techniques have been utilized in order to provide quantitative data on the behaviour of the micro

Time variation of whole human blood conductivity and shear stresses were investigated at rectangular and trapezium-shaped Couette viscometric flow under electric field of 2 kHz. The kinetics of conductivity signals were recorded both under transient flow and after the complete stoppage of shearing at shear rates from 0.94 to 94.5 s ⁻¹ and temperatures T=25°C and 37°C. Contraves Low Shear 30 rotational viscometer as a base unit and a concurrent measuring system, including a device, developed by the conductometric method with a software for measurement of conductivity of biological fluids (data acquisition system), previously described (IFMBE Proceedings Series, Vol. 11, 2005, pp. 4247–4252; Clin. Hemorheol. Microcirc. 35(1/2) (2006), 19–29), were used for the experiments. The obtained experimental relationships show that the human blood conductivity is time, shear rate, hematocrit and temperature dependent under transient flow. It is also dependent on the regime of the applied shear rates. Non-linear curve approximation of the growth and relaxation curves is done. The results show that valuable information could be received about the kinetics of “rouleaux formation” and the time dependences of the blood conductivity follow the structural transformations of RBC aggregates during the aggregation–disaggregation processes. The results suggest that this technique may be used to clarify the mechanism of dynamics of RBC aggregates.

Hemorheological abnormalities such as elevated whole blood viscosity, plasma viscosity, erythrocyte deformability and platelet aggregation, hematocrit and fibrinogen levels, are frequently examined as diagnostic tool and prognostic relevance in socially important hemorheological disorders. Distinct biological – morphological and functional platelet alterations, have been described in different addictions (heroin-, cocaine-, nicotine-, alcohol-, etc.). Chronic addictions could cause biochemical and conformational changes in platelets and their membranes, thus modulating platelet receptor expression, morphology (anisocytosis, giant platelets) and activation (alpha-granule release), platelet aggregation and hemorheological properties. Some of these alterations in chronic addicts – documented at cellular- and molecular level, could be easily used as a precise diagnostic tool with regard to thromboembolic complications and microcirulation injuries attributable to addictions. The present review focuses on some changes in platelet morphological, functional and rheological properties induced by chronic opiate/opioid abuse. Hypothesis is accumulated that free fatty acids (FFAs) and especially oleic acid (OA) could cause positive molecular and conformational changes in platelets of addicts with hemorheological disorders.

The study aimed to investigate the hemorheological parameters in patients with diabetes mellitus type 2 and to estimate their relationship with the cerebral and cutaneous blood flow and their responses to postural changes. The basic hemorheological constituents: hematocrit (Ht), fibrinogen (Fib), whole blood (WBV) and plasma viscosity (PV) were examined in 20 patients with diabetes mellitus type 2 and in 10 healthy age and sex matched controls. Blood flow velocity in the middle cerebral artery (MCA) was measured by transcranial Doppler monitoring at rest and during 5-min head-up tilt. Also laser Doppler-recorded tiptoe skin blood flow was investigated and venoarteriolar reflex perfusion responses to postural impact was monitored. Significant increase of Fib and WBV at shear rates of 0.0237 s ⁻¹ to 128.5 s ⁻¹ in the patients in comparison to controls was found. The postural challenge caused decrease of the cerebral blood flow velocity and increase of the resistance index (RI) in the diabetic patients. The initial mean skin perfusion values of the tiptoes and the venoarteriolar constriction response indices were significantly higher in the diabetes group. In the patients with diabetes mellitus type 2 the increased blood viscosity values were associated with impaired cerebrovascular and peripheral vascular responces.

The aim of the study is to investigate the changes of the skin blood flow responses to cold stress in patients with diabetes mellitus type 2 through wavelet analysis of the peripheral skin temperature oscillations and to estimate their relationship w