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.

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.

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.

The effects of acoustic and optokinetic stimulus on the postural stability

Objectives

Methods

Results

Conclusion

Level of Evidence

Vibrational heat capacity of silver carp collagen

The study of the experimental and calculated heat capacity, C_p of fish collagen (silver carp) with contents of several additive components was presented. The experimental low-temperature heat capacity was measured in the temperature range of 1.85 to 302.8 K using a Quantum Design Physical Property Measurement System (PPMS) and the higher temperature C_p from 223.15 K to 382.15 K by Differential Scanning Calorimetry (DSC) method. For an interpretation of the experimental, low-temperature data, the vibrational heat capacity of the pure silver carp collagen was calculated based on the contribution of a sum of the vibrational heat capacity of 4248 amino acids. The vibrational heat capacity for each amino acids was taken from Advanced Thermal Analysis System (ATHAS) Data Bank for individual poly (amino acid) residues based on their group and skeletal vibrational spectra. Comparing of the experimental heat capacity of the collagen with additive components and the calculated vibrational heat capacity of the pure silver carp collagen shows that the differences range from around 10% at 100 K to 14% at 300 K temperature. Such thermal analysis can provide information about the contribution to C_p of unknown components or impurities in the investigated system.

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.

In vivo electrical impedance measurement in human skin assessment

Structural and chemical alterations in living tissue are reflected in electrical impedance changes. However, due to the complexity of skin structure, the relation between electrical parameters and physiological/pathological conditions is difficult to establish. The impedance dispersion reflects the clinical status of the examined skin tissue and, therefore, it is frequently used in a non-invasive evaluation of exposing skin to various factors. The method has been used to assess the effect of the fish collagen on the skin of patients suffering from the leg ulcer. Therefore, from a number of different approaches to skin electrical impedance dispersion, the one considered to be safe was selected and applied. This paper presents a short review of different technical approaches to in vivo electrical impedance measurements, as well as an analysis of the results and the effect of fish collagen locally administered on human skin.

Minimally invasive treatments revitalizing facial skin - a case study

The increasing longevity of today’s societies has created a considerable need for the revitalization of facial skin undergoing the ageing processes. It is important to undertake preventive measures and start therapy when the first signs of ageing appear. This makes it possible to achieve a satisfactory effect while using minimally invasive procedures. Among them, treatments based on autologous preparations occupy a significant place, such as those using stem cells and concentrated growth factors (CGF), which have recently been introduced on the Polish market. Such a procedure was used on the patient described in this paper. In a series of instrumental studies, after three administrations of CGF-Harmony, improved values for the measurements reflecting skin elasticity were obtained, which was confirmed by instrumental examination of the skin using a Cutometer Dual MPA 580. Instrumental analysis of the mechanical parameters of facial skin makes it possible to demonstrate the effectiveness of treatment in the field of facial aesthetic medicine.

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.

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.

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.

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.

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.

The effect of temperature on the electric conductivity of poly(dimethyl siloxane) ferromagnetic gel

In this paper the influence of temperature on the electrical conductivity of a ferromagnetic gel is investigated. The material used was poly(dimethyl siloxane) (PDMS) gel which contained randomly distributed magnetite nanosized particles. The electrical conductivity was measured by means of the two-point dc method. During the heating of the PDMS in the temperature range of 295-460 K the electrical conductivity increased from about 2 × 10(-12) to 2 × 10(-8) S m(-1). A study of the current-temperature dependence obtained during subsequent heating runs revealed two subranges of temperature characterized by different activation energies. The presence of these subranges could be explained either by the liberation of two different types of charge carrier or by the increase in the degree of polymer cross-linking. In the upper temperature subrange (420-460 K) both types of charge carrier probably contribute to the electrical conductivity of PDMS ferromagnetic gel.

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 γ-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.

Temporary Changes in the dc ElectricalConductivity of MX (3-Chloro-4(Dichloromethyl)-5-Hydroxy-2(5H)-Furanone) Treated Collagen

The influence of MX(3-Chloro-4(Dichloromethyl)-5-Hydroxy-2(5H)- Furanone), a stronglymutagenic compound, on the temperature dependence of the dcelectrical conductivity of collagen as a function of time was studied.Collagen was immersed in MX solution, next dried and pressed intotablets. The MX concentration was measured by HPLC analysis.The reduction of MX concentration to 10% of the initial value wasobserved in the presence of collagen in the solution, whereas in thecontrol solution concentration of MX decreased to 70% of the initialvalue. Measurements of electrical conductivity were performed for thetemperature range 295-453K and activation energies for the chargeconduction process were calculated. Within the temperature range295-340K, the presence of MX decreased electrical conductivity ofcollagen. Calculated activation energies were typical for dry proteins.Within the temperature range 295-320K activation energy decreasedwith time, probably due to the stronger interactions in thecollagen-water-MX system. For temperatures between 320-410 and430-450K the activation energy was not time dependent and theapplication of MX did not change the structure of the collagenmacromolecule. The temporary changes occurring at the lowertemperatures being due solely to changes in the collagen-waterinteractions.

The influence of storage time on the temperature dependence of the dc electrical conductivity of horn keratin

The direct current electrical conductivity of horn keratin was measured as a function of temperature, in the temperature range 290-480 K, with a constant heating rate, for samples stored for periods of 2-3 weeks and 5 months. The activation energy of charge conducting process was calculated. The longer storage time reduced the water content, and the electrical conductivity, but increased the activation energy at 290-320 K.

The effect of gamma-irradiation on the temperature dependence of D.C. electrical conductivity of dry bone

The effect of gamma-irradiation with doses from 10 to 500 kGy on the electrical conductivity (g) of dry bone was studied. Temperature measurement of electrical conductivity were made from 393 to 533 K. The dependence obtained indicates the increase in g with temperature. An increase in irradiation dose resulted in a decreased g value for each dose up to temperature 462 K. Temperature 462 K was interpreted as the temperature of collagen melting point in dry bone. Above 462 K, g values were dose independent. A dose of 500 kGy shifted the melting point to lower temperature. In addition, the activation energy for the charge conduction process was calculated. Obtained values for electrical conductivity and activation energy were typical for dielectrics and indicated degradation of the organic component of bone.

Dielectric relaxation of air-dried horn keratin

Dielectric measurements as a function of temperature and frequency are reported for horn keratin. The measurements of dielectric constant epsilon' and loss factor epsilon", in keratin, were made in an electric field. This was done in the frequency range 10(1)-10(5) Hz and at temperatures from 22 to 220 degrees C. The samples contained 8% water by mass at room temperature at a relative humidity of 40%. A remarkable dispersion observed in the range of lower frequencies was attributed to interfacial polarization. The temperature dependences of the dielectric constants of horn keratin revealed the occurrence of two main molecular processes. The first process corresponded to the removal of water in the temperature range 22-170 degrees C. The activation energy associated with the release of loosely and strongly bound water, was about 35 and 7 kcal/mol, respectively. The second process, above 170 degrees C, was related to the denaturation of the alpha-helical phase in keratin.

Dielectric studies of proton transport in air-dried fully calcified and decalcified bone

Measurements of dielectric properties of calcified and decalcified bone were made in the electric field frequency range of 10(1)-10(5) Hz and at temperatures from 22 to 250 degrees C. The temperature dependencies of the complex dielectric constant of bone revealed two main molecular processes. The first process corresponds to the loss of water in the temperature ranges 22-160 degrees C and 22-210 degrees C for calcified and decalcified bone, respectively. The second is associated with the decomposition of collagen in bone, but this occurs only for decalcified bone above 210 degrees C. Analysis of polarization and conduction mechanisms for bone in the alpha-dispersion region was explained in terms of dielectric relaxation time and activation energy.

Studies of ferroelectric properties of collagen

Dielectric hysteresis loop and differential thermal analysis (DTA) studies of collagen were performed for temperatures ranging from a room temperature to 393 K. The material studied was collagen from Achilles tendon of a bullock, which contained 10% of water. The DTA curve for collagen with 10% of water showed a clear minimum at 353 K. The character of the curve proved that around 353 K an endothermic transformation of collagen took place which could be connected with the transition spiral-ball. A hypothetical dielectric hysteresis loop shows a maximum shift along the direction of the electric field applied in the vicinity of 375 K. Low frequencies of the applied electric field are connected with a great dielectric loss influencing the interpretation of collagen ferroelectricity.