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Objectives: Tinnitus is a sensation of ringing in the ears in the absence of any physical source in the environment. 15-25% of adults experience some form of tinnitus. A common cause of tinnitus is 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. Participants: Twelve patients with tinnitus, aged 30 to 74 years. Main outcome measures: The subjects all underwent audiological and neurological evaluation. Rheological properties of whole blood and plasma were assessed as well. The Quemada model was used to describe the variability of red blood cells shape, as well as their tendency to form aggregates. Results: Reduced whole blood viscosity in the low shear rate range is observed in the studied patient group. Conclusion: On the basis of the experimental study, statistically different results of hemorheological measurements were observed in the evaluated group in comparison to a reference group

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.

Hemoreologia jest nauką zajmującą się badaniem przepływu krwi w naczyniach krwionośnych. Parametry reologiczne mają znaczenie w patogenezie wielu chorób, w tym także w chorobach nowotworowych. Determinantami przepływu krwi są wartość hematokrytu, lepkość osocza, lepkość krwi pełnej oraz zdolność erytrocytów do deformacji i agregacji. Zmiany wartości lepkości krwi pełnej, lepkości osocza jak podwyższoną skłonność erytrocytów do agregacji i obniżoną zdolność do deformacji obserwuje się w przypadku wielu zmian nowotworowych. Wielu autorów wskazuje na możliwość wykorzystania badań reologicznych w prognozowaniu stopnia zawansowania choroby jak również wyboru metody terapeutycznej. Postulowane jest również modyfikowanie nadmiernej lepkości jako jednej z koncepcji leczenia chorób nowotworowych.

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.

Obec­ny tom to „o­krą­gła” dzie­siąt­ka. Tak jak po­przed­nie, po­wstał przede wszyst­kim dzię­ki au­to­rom, któ­rzy pod­ję­li wy­si­łek przy­go­to­wa­nia tek­stów i zde­cy­do­wa­li o ich pu­bli­ka­cji w po­szcze­gól­nych mo­no­gra­fiach wy­da­wa­nych w ra­mach se­rii „Bio­fi­zy­ka a Me­dy­cy­na”. Za­tem jest to oka­zja, aby po­dzię­ko­wać im wszyst­kim, a tak­że re­cen­zen­tom, Se­nac­kiej Ko­mi­sji ds. Wy­daw­nictw Uczel­ni oraz sa­me­mu Wy­daw­nictwu Nau­ko­we­mu Uni­wer­sy­te­tu Me­dycz­ne­go w Po­zna­niu. Ta ostat­nia in­sty­tu­cja to kon­kret­ni lu­dzie: kie­row­nic­two, re­dak­to­rzy. Dzię­ku­ję im ser­decz­nie za cier­pli­wość, za­an­ga­żo­wa­nie i pro­fe­sjo­na­lizm. Dzię­ku­ję też ko­le­żan­kom i ko­le­gom z Re­dak­cji Nau­ko­wej. Tom ten, wzo­rem lat ubie­głych, po­dzie­lo­ny jest na trzy czę­ści. Pierw­sza po­świę­co­na jest ko­la­ge­no­wi i bio­po­li­me­rom. Czy­tel­nik znaj­dzie tu pra­cę do­ty­czą­cą po­lok­sa­me­rów, ich po­ten­cja­łu bio­me­dycz­ne­go i prak­tycz­ne­go za­sto­so­wa­nia. Dla osób za­in­te­re­so­wa­nych te­ma­tem, któ­re chcia­ły­by zgłę­bić tę pro­ble­ma­ty­kę, umiesz­czo­no ade­kwat­ny wy­kaz pi­śmien­nic­twa. Nie­od­mien­nie tom za­wie­ra pra­ce do­ty­czą­ce ba­dań pod­sta­wo­wych. Tym ra­zem są to wy­ni­ki ba­dań ko­la­ge­nu róż­ne­go ty­pu pod­da­ne­go dzia­ła­niu bodź­ca ter­micz­ne­go prze­pro­wa­dzo­nych me­to­dą róż­ni­co­wej ka­lo­ry­me­trii ska­nin­go­wej. Wą­tek bio­po­li­me­rów zo­stał pod­ję­ty przez au­to­rów pra­cy po­świę­co­nej wy­ko­rzy­sta­niu chi­to­za­nu z do­dat­kiem hy­drok­sy­kwa­sów. Ma­ją­ce zba­wien­ne wła­ści­wo­ści że­le na ba­zie chi­to­za­nu z do­dat­kiem hy­drok­sy­kwa­sów mo­gą być wy­ko­rzy­sty­wa­ne do wy­twa­rza­nia ma­te­ria­łów opa­trun­ko­wych. Wła­ści­wo­ści me­cha­nicz­ne ko­la­ge­nu ma­ni­fe­sto­wa­ne są po­przez wła­ści­wo­ści me­cha­nicz­ne skó­ry. Czy­tel­nik w tej czę­ści znaj­dzie rów­nież roz­dział oma­wia­ją­cy moż­li­wo­ści ba­da­nia wła­ści­wo­ści bio­me­cha­nicz­nych skó­ry i róż­no­rod­ne aspek­ty ich za­sto­so­wań kli­nicz­nych. Wą­tek opa­trun­ków kon­ty­nu­owa­ny jest w pra­cy do­ty­czą­cej sto­ma­to­lo­gicz­nych ma­te­ria­łów kom­po­zy­to­wych i pro­ble­ma­ty­ki utrzy­ma­nia ich bar­wy. Jest to pra­ca sta­no­wią­ca nie­ja­ko po­most do ko­lej­nej czę­ści to­mu, do­ty­czą­cej pól elek­tro­ma­gne­tycz­nych. Część dru­gą otwie­ra pra­ca, w któ­rej przed­sta­wio­no wy­ni­ki za­sto­so­wa­nia me­dycz­ne­go urzą­dze­nia do ma­gne­to­sty­mu­la­cji wy­ko­rzy­sta­ne­go w sty­mu­la­cji na­sion. Mo­że to być po­czą­tek no­wej przy­go­dy z po­la­mi ma­gne­tycz­ny­mi. W czę­ści tej znaj­dzie­my też ar­ty­kuł opi­su­ją­cy spek­trum za­sto­so­wań fo­to­po­wie­la­czy w róż­nych dzie­dzi­nach me­dy­cy­ny. Część tę za­my­ka roz­dział po­świę­co­ny efek­tom bio­lo­gicz­nym fa­li ude­rze­nio­wej oraz te­ra­pii fa­lą ude­rze­nio­wą, w któ­rym zna­la­zły się m.in. roz­wa­ża­nia do­ty­czą­ce moż­li­wych me­cha­ni­zmów od­dzia­ły­wa­nia. Na­job­szer­niej­sza część po­świę­co­na jest bio­me­cha­ni­ce. Moż­na tu wy­róż­nić gru­pę prac do­ty­czą­cych po­stu­ro­gra­fii i gru­pę prac na te­mat he­mo­re­olo­gii. Na tre­ści tej czę­ści wy­raź­ne pięt­no od­ci­ska za­ra­za na­szych cza­sów – COVID-19. Czy­tel­nik znaj­dzie tu aż trzy pra­ce na ten te­mat. Jed­nych za­in­te­re­su­je wpływ le­ków sto­so­wa­nych w te­ra­pii COVID-19 na lep­kość kr­wi, in­nych – zmia­ny pa­ra­me­trów he­mo­re­olo­gicz­nych kr­wi. Z nie do koń­ca ja­snym w COVID-19 wpły­wem he­ma­to­kry­tu na lep­kość kr­wi, cięż­kość cho­ro­by, jak wska­zu­ją au­to­rzy, mo­że ko­re­lo­wać lep­kość oso­cza i wzrost ESR (ang. ery­th­ro­cy­te se­di­men­ta­tion ra­te). Ko­ro­na­wi­rus wy­wo­łu­je sze­reg spe­cy­ficz­nych re­ak­cji or­ga­ni­zmu, w tym za­bu­rze­nia czyn­no­ści ukła­du rów­no­wa­gi czło­wie­ka, któ­re­go stan mo­że być ana­li­zo­wa­ny za po­mo­cą po­stu­ro­gra­fii. Uwa­gę przy­ku­wa pra­ca wska­zu­jąca na przy­dat­ność tej me­to­dy w oce­nie za­bu­rzeń ukła­du rów­no­wa­gi bę­dą­cych na­stęp­stwem COVID-19. Pre­zen­tu­je ona pro­to­kół ba­da­nia or­ga­ni­za­cji zmy­sło­wej i kon­tro­li mo­to­rycz­nej. Ro­sną­ce za­in­te­re­so­wa­nie po­stu­ro­gra­fią ma­ni­fe­stu­je się m.in. w jej wy­ko­rzy­sta­niu w za­kre­sie oce­ny pa­ra­me­trów sta­nu od­ży­wie­nia pa­cjen­ta. Cie­ka­wa wy­da­je się oce­na wpły­wu tech­nik oste­opa­tycz­nych czasz­ko­wo­‑krzy­żo­wych na po­stu­ral­ność cia­ła i pra­cę ukła­du au­to­no­micz­ne­go.

Multimodal nanoparticles (NPs) that may be used for therapies and diagnostics is the most promising trend for efficient therapy. We demonstrate that nanocomposite based on self-organizing silver and ultrasmall magnetic iron oxide NPs (MAg) produced in one-step synthesis revealed unique combination of fluorescence, bactericidal, fungicidal properties and have a potential as magnetic resonance imaging (MRI) contrast agent. Using the green chemistry approach, ginger (Zingiber officinale) rhizome extract was applied as capping agent for MAg synthesis, providing also additional fluorescent properties of NPs and inducing hydrocolloids structuring. The MAg were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive microanalysis (EDS), fluorescence microscopy, cryo-SEM, dynamic light scattering (DLS) techniques, Fourier transform infrared (FTIR) and ultraviolet–visible (UV–Vis) spectroscopies. MAg dispersions in water and some biological media are very stable which is important for biomedical application. The existence of microstructure in MAg hydrocolloids was proved. The hierarchical character and high ordering of this microstructure were discovered and its level-by-level building blocks were investigated. The microstructure was found to be responsible for fluorescence emittance of MAg hydrocolloids. The properties as well as potential application of the MAg hydrocolloids is yet to be discovered. Keywords: Ultrasmall, Silver, Ginger, Nanoparticles, Hydrocolloid, Microstructure

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.

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.

Background. Yield shear stress (YSS) well characterizes the thixotropic status of blood, that exemplifies a reversible loss of blood fluidity due to a low shear rate. At the stable haematocrit ratio YSS depends mainly on the fibrinogen level.Aim. Since the role of other biochemical factors in the YSS phenomenon in cerebral ischaemia has not been well known, we have undertaken this problem in a group of stroke patients. Material and Methods. The study was carried out in 36 patients with acute ischaemic stroke and in 12 controls. YSS was estimated by means of microviscometric method. In all subjects the concentration of the following biochemical factors were assayed: albumin, IgG, IgA, IgM, apolipoprotein A, and B, cholesterol, triglycerides, LDL, HDL and fibrinogen. Then the thixotroipic effect of all biochemical factors and their correlations to fibrinogen were estimated by means of mathematical formulas.Results. We found a positive correlation in relation to the following thixotropic effects: for all subjects and separately for patients’ group: Alb(YSS) (p

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.

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.

The influence of magnetic field on whole blood rheological properties remains a weakly known phenomenon. Anin vitroanalysis 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.

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.

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.

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.

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 (p0.001).