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.

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.

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.

Comparing the Efficacy of Monopolar and Bipolar Radiofrequency Treatment on Facial Skin in Women.

Objective: The present research compared the effectiveness of the monopolar radiofrequency method with that of bipolar method in the facial skin of women in selected age groups. Methods: The study included 150 women with good general health and healthy skin. The first group comprised 75 female participants who received monopolar radiofrequency electromagnetic field treatment (RFM) and 75 women who were treated using the bipolar method (RFB). In both the RFM and RFB groups, five age groups were distinguished: Group I (20-29 years), Group II (30-39 years), Group III (40-49 years), Group IV (50-59 years), and Group V (60-69 years). Transepidermal water loss (TEWL) was measured using tewametry to determine stratum corneum barrier function and corneometry was used to measure epidermal hydration. Tewametric and corneometric measurements of the facial skin were performed to determine its condition following radiofrequency electromagnetic field therapy and to assess the sustainability of the obtained results after four months of therapy. The follow-up measurement was performed prior to the first treatment session and the subsequent ones after one month, and four months following the first measurement. Results: The best results, indicating an improvement in epidermal hydration were observed for bipolar radiofrequency method in the age group 40-49 years and group 50-59 years.

Venous leg ulcers treated with fish collagen gel in a 12-week randomized single-centre study.

Introduction: Venous ulcers are difficult to heal chronic wounds. Most challenging are the non-healing and recurrent ulcers, because of which we are seeking for therapies that stimulate and support their healing. Aim: To assess the efficacy of fish collagen and its impact on the process of healing of venous leg ulcers. Material and methods: This 12-week randomized single-centre study included a total of 97 adults with venous leg ulcer, randomized into two groups: the study group (n = 48) and the control group (n = 49). All patients received specialist medical care including skin and limb care, wound development according to the TIME scheme (tissue debridement, infection and inflammation control, moisture balance, edge) and short-stretch bandage compression (compression class II). In addition, the study group received tropocollagen gel applied to the skin around the wound. Every 2 weeks we evaluated the wound surface and temperature distribution on the shin (average temperature, median, minimum and maximum) - symmetrically on the sick and healthy limb. Results: We observed a greater number of complete ulcer healing in the study group (week 12: 29.2% vs. 22.4%; week 24: 52.1% vs. 36.7%). Faster healing time in the study group was observed in both big and small ulcers. The thermographic analysis showed statistically significant reduction in periwound inflammation among patients from the study group (p < 0.05). Statistically significant reduction in mean as well as maximum values of limb temperature occurred only in the study group (Tx: R = 0.37, p < 0.001; Tmax: R = 0.40, p < 0.001). Conclusions: Thermographic analysis showed better wound healing effects in the group using tropocollagen. Significant impact of collagen on the healing process was observed only after 8 weeks of application.

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.

Instrumental diagnosis of facial skin-A necessity or a pretreatment recommendation in esthetic medicine.

BACKGROUND: This paper presents the possibilities of pretreatment instrumental diagnosis for assessing the condition of various facial skin areas. AIM: Tests which aimed at determining the firmness and elasticity of facial skin were conducted. METHODS: Analysis of skin parameters in selected facial areas in adults over a wide age range was performed using the Cutometer Dual MPA 580 probe. Parameters R0, R2, R5, R7, R8, and R9 were analyzed. RESULTS: The following results were obtained: R0 (0.20-0.33) mm; R2 (0.66-0.82) a.u.; R5 (0.60-0.92) a.u.; R7 (0.37-0.52) a.u.; R8 (0.10-0.27) mm; and R9 (0.03-0.05) mm. The R0 parameter showed no statistically significant correlation between skin firmness and age. On the basis of the other parameters, it can be concluded that skin elasticity and an ability to return to its original shape around the eyes, on the cheeks and around the lips, are greater in younger patients than in older groups. There were no statistically significant differences within each age group between the right and left sides of the face. CONCLUSION: Skin firmness described by the R0 parameter is constant in the studied groups and independent of age. Skin elasticity, and an ability to return to its original shape around the eyes, on the cheeks and around the lips, is greater in younger patients. The aging process simultaneously affects the entire facial skin.

The electrical properties and glass transition of some dental materials after temperature exposure.

The physicochemical properties of dental materials will remain stable only when these materials in question are resistant to the changes in the oral cavity. The oral environment is subject to large temperature variations. The aim of the study was the assessment of electrical properties and glass transition of some dental materials after temperature exposure. Composite materials, compomers, materials for temporary prosthetic replacement and resin-based pit and fissure sealants were used in the study. The method used was electric conductivity of materials under changing temperature. The order of materials presenting the best characteristics for insulators was as follows: materials for temporary prosthetic replacement, resin-based pit and fissure sealants, composites, and compomers. Thanks to comparisons made between graphs during I and II heating run, the method could be used to observe changes in the heated material and determine whether the changes observed are reversible or permanent. The graphs also provided temperature values which contain information on glass transition during heating. In the oral cavity the effect of the constant temperature stimulus influences maturity of dental materials and improves their properties. But high temperatures over glass transition temperature can cause irreversible deformation and changes of the materials properties, even in a short time.

Comparison of thermal properties of fish collagen and bovine collagen in the temperature range 298-670K.

The increased interest in fish collagen is a consequence of the risk of exposure to Creutzfeld-Jacob disease (CJD) and the bovine spongiform encephalopathy (BSE), whose occurrence is associated with prions carried by bovine collagen. Collagen is the main biopolymer in living organisms and the main component of the skin and bones. Until the discovery of the BSE, bovine collagen had been widely used. The BSE epidemic increased the interest in new sources of collagen such as fish skin collagen (FSC) and its properties. Although the thermal properties of collagen originating from mammals have been well described, less attention has been paid to the thermal properties of FSC. Denaturation temperature is a particularly important parameter, depending on the collagen origin and hydration level. In the reported experiment, the free water and bound water release processes along with thermal denaturation process were studied by means of the differential scanning calorimetry (DSC). Measurements were carried out using a DSC 7 instrument (Elmer-Perkin), in the temperature range 298-670K. The study material was FSC derived by acidic hydration method. The bovine Achilles tendon (BAT) collagen type I was used as the control material. The thermograms recorded revealed both, exothermic and endothermic peaks. For both materials, the peaks in the temperature range of 330-360K were assigned to the release of free water and bound water. The denaturation temperatures of FSC and BAT collagen were determined as 420K and 493K, respectively. Thermal decomposition process was observed at about 500K for FSC and at about 510K for BAT collagen. These results show that FSC is less resistant to high temperature than BAT collagen.

The influence of the acoustic stimulus on postural stability.

PURPOSE: The purpose of this study was to assess if 65 dB and 4000 Hz stimuli affect postural stability of young normally hearing people. METHODS: Posturography examinations belong to clinical tests which evaluate the motor skills. Posturography can be divided into static posturography and dynamic posturography. In both static and dynamic posturography patient stays on the platform with opened and closed eyes, but in the case of dynamic one, platform is unstable. In this study the Multitest Equilibre platform produced by FRAMIRAL was used. Patients took part in tests with opened and closed eyes, on stable and unstable platform. Additionally, patients were exposed to 65 dB and 4000 Hz acoustic stimuli. The sound pressure level, and frequency was belonging to the best audibly frequency range. RESULTS: Parameters such as velocity and surface were examined. The difference between velocity measured with acoustic stimuli and without acoustic stimuli was observed. On the other hand there was no difference in surface results. CONCLUSIONS: The statistically significant difference between velocity of patients center of gravity movements, measured on unstable platform, in the presence of 4000 Hz, 65 dB acoustic stimulus and without additional disturbances was observed.

Amino acid composition in determination of collagen origin and assessment of physical factors effects.

The amino acid composition of collagen is a characteristic feature of this protein. Collagen, irrespective of its origin, contains 19 amino acids, including hydroxyproline which does not occur in other proteins. Its atypical amino acid composition is characterized by high content of proline and glycine, as well as the absence of cysteine. This paper shows the comparison of qualitative composition of amino acids of fish skin (FS) collagen, bovine Achilles tendon (BAT) collagen, and bone collagen. Results demonstrate that FS collagen as well as BAT collagen contains no cysteine and significantly different amount of hydroxyproline. In BAT collagen hydroxyproline content is 30% higher than hydroxyproline content of FS collagen. In bone collagen the amount of hydroxyproline is two times more than in FS collagen. Furthermore, it is shown that sensitivity to radiation of individual amino acids varies and depends on the absorbed dose of ionizing radiation. The changes observed in the amino acid composition become very intense for the doses of 500kGy and 1000kGy.

Time-dependent changes in dynamic mechanical properties of irradiated bone.

The increased use of allograft tissue for musculoskeletal repair has brought more focus to the safety of allogenic tissue and the efficacy of various sterilization techniques. The currently available literature contains few examples of studies on long-lasting strains of bones but no example for irradiated bones. In this study the bovine femurs from a 2-year-old animal were machine cut and irradiated with the doses of 10, 15, 25, 35, 45 and 50 kGy. The dynamic mechanical analysis was performed at 1 Hz at the room temperature in a 3-point bending configuration for 2880 minutes. The final values of E' and E″ were dose independent but they were reached at different periods. For this reason, so called "critical point" was introduced for the further analysis. All the examined sample groups were characterized by statistically significant lower values of the critical point in comparison with the control samples (p<0.05) but the biggest differences were observed between the control samples and the samples irradiated with the doses of 10, 15 and 25 kGy. Current results and literature review suggest that the dose of 35 kGy is the optimal dose for ionizing radiation sterilization.

Radiation sterilized bone response to dynamic loading.

Allogeneic bone grafts are used on a large scale in surgeries. To avoid the risk of infectious diseases, allografts should be radiation-sterilized. So far, no international consensus has been achieved regarding the optimal radiation dose. Many authors suggest that bone sterilization deteriorates bone mechanical properties. However, no data on the influence of ionizing radiation on bone dynamic mechanical properties are available. Bovine femurs from 2-year old animal were machine cut and irradiated with the doses 10, 15, 25, 35, 45 and 50 kGy. Dynamic mechanical analysis was performed at 1-10 Hz at the temperature range of 0-350 °C in 3-point bending configuration. No statistically significant differences in storage modulus were observed. However, there were significant decreased values of loss modulus between the samples irradiated with doses of 10 (↓14.3%), 15, 45 and 50 kGy (↓33.2%) and controls. It was stated that increased irradiation dose decreases the temperature where collagen denaturation process starts and increases the temperature where the collagen denaturation process finishes. It was shown that activation energy of denaturation process is significantly higher for the samples irradiated with the dose of 50 kGy (615 kJ/mol) in comparison with control samples and irradiation with other doses (100-135 kJ/mol).

The sun--our friend or foe?

INTRODUCTION AND OBJECTIVE: Sunlight is the major source of the energy on Earth. Visible light, ultraviolet and infrared radiation are necessary to sustain life on our planet. However, besides the range of positive effects, such as photosynthesis in plants, warmth, vision, and synthesis of vitamin D, sunlight may also be responsible for negative biologic effects - sunburn, induction of photodermatoses or carcinogenesis. Ultraviolet is regarded as the major environmental, physical hazard to the human skin. ABBREVIATED DESCRIPTION OF THE STATE OF KNOWLEDGE: The acute clinical effect of ultraviolet involves melanogenesis, i.e. tanning, which protects from sunburn if exposure is overdosed. A single exposure, as well as acute suberythemal irradiation, suppresses sensitization of the contact hypersensitivity. The chronic biological effects are photoageing and skin cancer, especially squamous cell carcinoma (SCC). Vitamin D synthesis is regarded as a benefit of natural acute and chronic exposure to ultraviolet. Ultraviolet also plays an important role in aetiology of the group of disorders characterized by photosensitivity. On the other hand ultraviolet is a known inducer of immunosuppression in the skin; therefore, phototherapy is a therapeutic option for patients with activation of dermal immunity. SUMMARY: Without sunlight, the existence of life on Earth is not possible. On the other hand, UVR radiation is regarded as representing one of the most important environmental hazards for human skin. For a better understanding of the mechanisms related to the influence of UVR on human skin, and the most dangerous chronic effects of carcinogenesis, it is necessary to undertake some protective activities. Moreover, UVR may become our ally in the treatment of selected skin disorders.

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.

FT NIR Raman studies on gamma-irradiated bone.

Exciting with the Nd:YAG laser line at 1064 nm allows to receive high-quality, fluorescence-free Raman spectra of biomaterials. The paper presents investigations of Raman scattering from the bone irradiated with gamma radiation up to the dose of 1000 kGy. Results of Raman spectra studies of gamma-irradiated bone allowed to show that inorganic component of the animal bone are more sensitive to gamma radiation than the organic component. The changes in the irradiated bone were evaluated on the basis of the changes in the intensities of line, changes in their position and changes in some important ratios. Independent determination of the protein content and the content of some important amino acids were compared with the data obtain in the Raman studies. The majority of the bands assigned to organic component of bone were affected by doses higher than 100 kGy.

Changes in thermal and electrical properties of bone as a result of 1 MGy-dose gamma-irradiation.

Determination of temperature dependencies of electric conductivity and thermal properties by differential scanning calorimetry (DSC) allow to analyse the processes of charge and heat transport in the bone being a complex collagen-hydroxyapatite (HAP)-water system. Modification of the bone structure by high doses of gamma-radiation changes the electrical and thermal properties of the bone. Electrical conductivity (sigma) of the bone decreases with consecutive heating runs. The decrease in sigma observed for irradiated samples was explained by the scission of the main chain of collagen macromolecule. Irradiation decreased the hydration level in the bone, its denaturation temperature and increased both enthalpy and entropy of the denaturation process.