Ulcerated skin evaluation by electrical impedance measurements.

In the presented study, the transdermal results from the areas surrounding the ulcerated skin areas were compared with those obtained from healthy skin tissue. The analysis of electrical parameters, such as the slope of the Nyquist plot, min. IM, min. RE, min. f, Imagine part index, Phase index, Real part index, and Magnitude index were conducted. Electrical parameters have been measured in the group without lower leg ulceration and in the group with lower leg ulcers. On the basis of the statistical analysis, it was determined that these parameters may be effective in the evaluation of the skin. In fact, the skin surrounding the ulceration was characterised by different values of electrical parameters as compared with healthy skin tissue. A statistically significant difference was found in the electrical parameters obtained for the healthy leg skin and the skin surrounding the ulceration. This study was to investigate the applicability of electrical parameters in the evaluation of the skin in lower leg ulcers. The electrical parameters can be used as an effective tool in assessing the condition of the skin, both healthy and surrounding the ulcerations. The most useful parameters in assessing skin condition using electrical parameters include min. IM, min. RE, min. f, Imagine part index, Phase index, and Magnitude index.

Influence of magnetostimulation therapy on rheological properties of blood in neurological patients.

The aim of the study is to test the influence of in vivo magnetostimulation on the rheological properties of blood in neurological patients. Blood circulation in the body depends both on the mechanical properties of the circulatory system and on the physical and physicochemical properties of blood. The main factors influencing the rheological properties of blood are as follows: hematocrit, plasma viscosity, whole-blood viscosity, red cells aggregability, deformability, and the ability of red cells to orient in the flow. The blood samples were collected from neurological patients with pain. Blood samples were collected twice from each patient, that is, before the magnetostimulation and immediately after the therapy. For each blood sample, the hematocrit value was measured using the standard method. Plasma viscosity and whole-blood viscosity were measured by means of a rotary-oscillating rheometer Contraves LS40. Magnetic field was generated by the instrument Viofor JPS® and the magnetostimulation treatments were performed using M1P2 and M1P3 programs. The analysis of the results included estimation of the hematocrit value (Hct), plasma viscosity (ηp), whole-blood viscosity and rheological parameters of Quemada's model: k0, k∞, γ'c. Plasma viscosity values were obtained from the shear rate dependence of shear stress using the linear regression method. The results obtained in the study suggest that the blood rheological properties change in accord with applied magnetostimulation program.

Interdependence of Rheological and Biochemical Parameters of Blood in a Group of Patients with Clinically Silent Multifocal Vascular Cerebral Lesions.

BACKGROUND: Hemorheology is a field of science which often becomes interesting to researchers studying impairments related to blood flow disturbances. Clinically silent vascular cerebral lesions (CSVCLs) are considered a problem of great importance in neurology. OBJECTIVE: This work aimed to analyze the interdependencies of the rheological and biochemical parameters of the blood. METHODS: The group of patients included persons with clinically silent multifocal vascular cerebral lesions diagnosed using neuroimaging. The control group had no symptoms in the central nervous system (CNS). We analyzed hemorheological profiles in 69 patients with CSVCLs diagnosed via magnetic resonance imaging (MR) or 64-row computer tomography measurements. Rheological data were acquired using a rotary-oscillating rheometer, the Contraves LS-40, an instrument dedicated to blood viscosity measurements. For each sample, the hematocrit value was measured using the standard method. Analysis of erythrocytes' aggregability and deformability was performed using the rheological model of Quemada. Biochemical tests of blood were also performed. RESULTS: The results of rheological and biochemical studies were compared with those obtained in the control group. Special attention was paid to the correlation analysis of rheological and biochemical parameters. CONCLUSIONS: Such correlations were found, e.g., between the red cells' deformability and the fibrinogen level. The results improve our understanding of blood flow hemodynamics by analyzing the shear-dependent behavior of the aggregation and deformability of red blood cells.

Can Assessment of Rheological Properties of Whole Blood and Plasma Be Useful in the Diagnosis of Tinnitus? A Pilot Study.

Tinnitus is a sensation of ringing in the ears in the absence of any physical source in the environment. Between 9-35% of adults experience some form of tinnitus. Common causes of tinnitus include noise, head injury, ototoxic substances, as well as disorders of blood and blood vessels. Vascular causes include: head-neck tumours, turbulent blood flow, problems with blood supply and inner ear cell damage. The aspect of rheology in terms of tinnitus has not been described yet. In the present study, which comprised 12 patients aged 30 to 74 years presenting with tinnitus, rheological properties of whole blood and plasma were assessed. All the subjects underwent audiological and neurological evaluation. The Quemada model was used to describe the variability of red blood cell shape, as well as their tendency to form aggregates. On the basis of the experimental study, statistically different results of haemorheological measurements were observed in the evaluated group in comparison to a reference group.

Body Balance Analysis in the Visually Impaired Individuals Aged 18-24 Years.

BACKGROUND: Proper body balance is maintained by both sensory, i.e., vision, hearing, vestibular, and proprioception, and motor nervous systems. Visual control facilitates balance both in a static position, as well as during movement. Visual dysfunctions can adversely affect balance and stability control. METHODS: The study comprised a group of 30 individuals visually impaired from birth aged 18-24 years. The control group consisted of 50 persons in the same age range as the study group. The trial was performed as four separate tests: two on a stable surface platform, and two on an unstable surface platform. RESULTS: No statistically significant differences were found in the posturography test on the stable platform between the study groups. When tested on an unstable ground surface, the visually impaired subjects obtained showed worse performance than the sighted persons. Statistically significant differences were observed in the majority of the analyzed results. CONCLUSIONS: Visually impaired individuals present a poorer ability to maintain balance under dynamic conditions. Tests conducted on the unstable surface platform seem to be more relevant and applicable in the diagnosis of the subjects with visual impairment, as they differentiate the subjects to a greater extent.

The effects of acoustic and optokinetic stimulus on the postural stability.

Objectives: This article addresses the question of whether the simultaneous auditory and optokinetic stimulation affects the postural stability differently than only the stimulation with a single auditory or optokinetic stimulus. Methods: The study involved 30 volunteers. The postural stability was evaluated by means of the posturography platform, which allows for both stable and dynamic posturography tests as well as for applying optokinetic stimulus. Three series of measurements were performed in each patient: measurements on an only with the optokinetic stimulus, measurements using only the acoustic stimulus, and finally measurements with both stimuli applied simultaneously. Results: The results indicate that there are statistically significant differences in the findings obtained with the simultaneous auditory and visual stimulation and the observed results with only one of the stimuli on the dynamic platform. Hence, on the basis of the results obtained, it is possible to conclude that the acoustic stimulus has the potential to help maintain a stable posture. However, this process is not sufficiently compensated with the optokinetic stimulation alone. Conclusion: The sense of sight may be essential for the maintenance of a stable posture. The presence of a sound stimulus improves the postural stability, although this improvement does not compensate for the disturbance caused by the optokinetic stimulus. Hence, functioning of auditory and visual system can influence patients posture. Level of Evidence: 4.

Comparative analysis of chosen hemorheological methods in a group of stroke patients.

Blood viscosity is one of the most important factors determining the blood flow. In this report we describe changes in whole blood viscosity in a group of patients after stroke measured as a function of the shear rate (flow curve) and also blood visco-elastic properties measured using oscillatory methods (dynamical mechanical analysis). The principle of the latter method is based on the measurement of the amplitude and phase of the sample oscillations driven by controlled harmonic strain. All measurements were performed by means of a rotary-oscillatory rheometer Contraves LS-40.

Rheological parameters of saliva in comparison with taste examination.

BACKGROUND: It is generally unknown if taste sensitivity is dependent upon saliva viscosity. The rheological properties of saliva result from many factors and it has been shown to behave as a non-Newtonian fluid whose viscosity decreases with increasing shear rate. Taste sensitivity may be quantitatively assayed by electro-gustometry. OBJECTIVES: The aim of this work was to compare saliva rheological properties, obtained with a rotary-oscillating rheometer, to quantitative measures of taste sensitivity, using electro-gustometry. METHODS: Saliva samples were taken from 27 healthy non-smoking donors - 7 men and 20 women aged 18-65 years (mean age - 37 years). After thresholds of taste sensation were measured, the saliva samples were taken and characterized in terms of their rheological properties and pH. Saliva viscosity was measured in the order of decreasing shear rate in the range 100-0.01 s-1. Viscoelastic properties were examined under constant frequency oscillations (with f = 0.5 Hz) and with decreasing shear effective amplitude γeff'. RESULTS AND CONCLUSIONS: Saliva viscosity was found to decrease with increasing shear rate and varied with time. Analysis of the dependence of the viscosity values of saliva and components of complex viscosity did not show a significant correlation with taste sensation. A dependency of taste sensation on pH could not be discerned due to the narrow range of naturally occurring pH.

Hemorheological changes dependent on the time from the onset of ischemic stroke.

This work aimed at estimation and comparison of chosen rheological parameters of blood in two group of patients in acute and remote stroke phase. The analysis included the values of shear stress, plasma viscosity, relative blood viscosity, hematocrit value and the parameters of rheological Quemada model of blood flow. The main two groups (30 persons each) consisted of patients after cerebral ischemic episode, remaining under permanent medical control, the first one in the acute and the second in the remote phase. The reference group (20 persons) included the patients who never suffered from any circulatory system disorders and who did not take any drugs affecting the hemorheological parameters. The results suggest that after a distinct increase of most of the hemorheological parameters in the acute stroke phase, a gradual improvement was observed in the remote phase. Since in the latter group the plasma viscosity remained on elevated level, we suggest a creation of a specific feedback mechanism leading to a decrease of the blood viscosity and thus better perfusion of brain. The analysis of Quemada model parameters indicates that the decrease of blood viscosity may result from the increased red cell deformability.

Comparison of three rheological models of shear flow behavior studied on blood samples from post-infarction patients.

Quantitative analysis of blood viscosity was performed on the basis of mathematical models of non-Newtonian fluid shear flow behavior (Casson, Ree-Eyring and Quemada). A total of 100 blood samples were drawn from clinically stable survivors of myocardial infarction, treated with aspirin or acenocoumarol and controls to these drugs. Whole blood and plasma viscosity were measured at a broad range of shear rates using a rotary-oscillating viscometer Contraves LS40. Numerical analysis of the experimental data was carried out by means of linear (for Casson) and non-linear regression for the remaining models. In the evaluation of the results, both the fit quality and physical interpretation of the models' parameters were considered. The Quemada model fitted most precisely with the experimental findings and, despite the controversies concerning the relationship between in vivo tissue perfusion and in vitro rheological measurements, seemed to be a valuable method enhancing investigation possibilities of cardiovascular patients. Our results suggest that aspirin does not affect blood rheological properties, while acenocoumarol may slightly alter red cell deformability and rouleaux formation.

Blood fluidity and thermography in patients with diabetes mellitus and coronary artery disease in comparison to healthy subjects.

The study aimed at initial determination and analysis of selected rheological parameters of blood in the group of diabetics and patients after myocardial infarction and compare the results to the symptoms observed in thermographical studies. The parameters studied were: whole blood viscosity, plasma viscosity, relative blood viscosity and hematocrit value. A group of 60 subjects took part in the study. The control group (20 persons) included the healthy subjects who had never suffered from any circulatory system disorders and who did not receive any drugs affecting the hemorheological parameters. The group of diabetics included 18 patients and the group after myocardial infarction included 20 patients. Blood viscosity measurements were performed by means of a rotary-oscillatory reometer Contraves LS 40 at the decreasing shear rate ranging from 100-0.01 s(-1) during a period of 5 minutes. For each blood sample the hematocrit value was measured using the standard method. The plasma viscosity was calculated from the linear regression of the shear rate dependence of the shear stress measured by means of the Contraves LS 40 reometer.

The changes of low-shear-rate hemorheological properties depending on the fluid used for transfusion.

We investigated the influence of kind of fluids used for transfusion - crystalloids and colloids - on the rheological parameters of blood with a special focus on the range of low shear rates. The blood viscosity measurements were performed with the use of a rotary-oscillatory rheometer Contraves LS 40. The investigation includes the measurements of blood viscosity and a hematocrit value at three stages: before, just after and two hours after transfusion. On the basis of results obtained for a group of patients prepared for procedures in epidural anaesthesia we concluded that the dilution effect for colloids (HES and dextran) was maintained longer then for crystalloids (Ringer solution). Measurements of blood viscosity at the shear rate of 1 s(-1) showed that this viscosity had the smallest value in the group of patients with HES 200/0.5 as a transfusion fluid (p<0.001).

[Comparison of whole blood viscosity in vascular diseases]. / Porównanie lepkosci krwi pelnej w wybranych stanach chorobowych ukladu naczyniowego.

The viscosity of whole blood taken from patients suffering from different diseases was studied. The measurements of blood viscosity were performed in the shear rate range 0.01-100 s-1 in three groups of patients. The first group consisted of 60 patients without known cardiovascular disorders referred for a non-vascular minor surgery (patients did not take any drugs influencing vascular system). The second group (30 persons) consisted of patients after cerebral ischemic episode, remaining under permanent medical control. The third group consisted of 100 patients after myocardial infarction. In the group of patients suffering from vascular system disorders (second and third) the blood viscosity has been significantly lower then in the first group. Such results might suggest that in patients with vascular system disorders blood viscosity has been decreased in the way of specific feedback mechanism, whereas the beneficial hemorrheological influence of secondary prevention seems to be questionable.

The effect of pulsed IR-light on the rheological parameters of blood in vitro.

In this study we attempted to assess the effect of light of 855 nm wavelength (IR-light) on the rheological parameters of blood in vitro. As an anticoagulant, heparin was used. The source of IR-light was an applicator connected to the special generator--Viofor JPS®. The blood samples were irradiated for 30 min. During the irradiation the energy density was growing at twelve-second intervals starting from 1.06 J/cm2 to 8.46 J/cm2, then the energy density dropped to the initial value; the process was repeated cyclically. The study of blood viscosity was carried out with a Contraves LS40 oscillatory-rotational rheometer, with a decreasing shearing rate from 100 to 0.01 s⁻¹ over 5 min (flow curve) and applying constant frequency oscillations f=0.5 Hz with decreasing shear amplitude ˙γ0 (viscoelasticity measurements). The analysis of the results of rotational measurements was based on the assessment of hematocrit, plasma viscosity, whole blood viscosity at four selected shear rates and on the basis of the numerical values of parameters from Quemada's rheological model: k0 (indicating red cell aggregability), k∞ (indicating red cell rigidity) and ˙γc (the value of the shear rate for which the rouleaux formation begins). In oscillatory experiments we estimated viscous and elastic components of the complex blood viscosity in the same groups of patients. We observed a decrease of the viscous component of complex viscosity (η') at ˙γ0=0.2 s⁻¹, while other rheological parameters, k0, k∞, and relative blood viscosity at selected shear rates showed only a weak tendency towards smaller values after irradiation. The IR-light effect on the rheological properties of blood in vitro turned out to be rather neutral in the studied group of patients.

Analysis of the magnetic field influence on the rheological properties of healthy persons blood.

The influence of magnetic field on whole blood rheological properties remains a weakly known phenomenon. An in vitro analysis of the magnetic field influence on the rheological properties of healthy persons blood is presented in this work. The study was performed on blood samples taken from 25 healthy nonsmoking persons and included comparative analysis of the results of both the standard rotary method (flow curve measurement) and the oscillatory method known also as the mechanical dynamic analysis, performed before and after exposition of blood samples to magnetic field. The principle of the oscillatory technique lies in determining the amplitude and phase of the oscillations of the studied sample subjected to action of a harmonic force of controlled amplitude and frequency. The flow curve measurement involved determining the shear rate dependence of blood viscosity. The viscoelastic properties of the blood samples were analyzed in terms of complex blood viscosity. All the measurements have been performed by means of the Contraves LS40 rheometer. The data obtained from the flow curve measurements complemented by hematocrit and plasma viscosity measurements have been analyzed using the rheological model of Quemada. No significant changes of the studied rheological parameters have been found.