Bogdan. Walkowiak

• Lodz University of Technology

The laser surface modification of metallic implants presents a promising alternative to other surface modification techniques. A total of four alloyed metallic biomaterials were used for this study: medical steel (AISI 316L), cobalt–chromium–molybdenum alloy (CoCrMo) and titanium alloys (Ti6Al4V and Ti6Al7Nb). Samples of metallic biomaterials after...

In this article, the properties of thermosensitive chitosan hydrogels (structural and biological) prepared using chitosan chloride and β‐glycerophosphate are presented. The porous structure of the gels was observed with a scanning electron microscopy (SEM). Rheological and other structural and morphological investigations were carried out by infrar...

Objective This study aimed to present a new possibility to create radio-opaque implant material for craniomaxillofacial reconstruction. Materials and methodsThe test disks made of the own compound of polyethylenes with addiction of 2, 4, and 6 % of weight TiO2 was investigated for cytotoxicity [each group 15 disks respectively]. Next, computed tomo...

In this article, properties of thermosensitive chitosan hydrogels prepared with the use of chitosan chloride with β-glycerophosphate disodium salt pentahydrate enriched with calcium glycerophosphate are presented and compared with chitosan hydrogels with β-glycerophosphate disodium salt pentahydrate. The study is focused on the determination of hyd...

The aim of this study was to examine the thrombogenic properties of polyurethane that was surface modified with carbon coatings. Physicochemical properties of manufactured coatings were investigated using transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS), Raman spectroscopy and contact ang...

Most biomaterials at present have sufficient mechanical properties; however compliance with standards for biocompatibility is often not sufficient in clinical practice. This may be due to the complexity of biological systems in general and the diversity of individual responses to these materials by implant recipients. Significant improvement of bio...

This work studied the susceptibility of biofilm produced by E. coli to oxidative stress, and compared the components of free radicals defences: level of glutathione, catalase and dismutase activities in planktonic and biofilm located cells. Results showed the diversity of responses to oxidative stress in bacterial cells in log or stationary phases...

Iron doped titanium dioxide coatings were synthesized with the help of RF plasma enhanced CVD technique. As a source of titanium, titanium chloride (IV) TiCl4 was used while iron pentacarbonyl (0) Fe(CO)5 served as iron supply. The coatings were diagnosed using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Their elemental an...

A simple synthetic α-methylene-δ-lactone, 1-isopropyl-2-methylene-1,2-dihydrobenzochromen-3-one, designated DL-3, was shown previously to induce apoptosis and significantly suppress cell metastatic potential in MDA-MB-231 breast cancer cells. The mechanisms through which DL-3 exerts its effects are poorly understood. The purpose of this study was t...

Introduction: The authors have been using patient-specific implants since 2006 and are constantly looking for new reconstructive materials, in order to create precise implants for orbital reconstruction. Such materials should be biocompatible and stable in the human body, as well as easy to machine and form into complex 3D shapes. Biocompatible ul...

The aim of the present research was to assess the differences in blood platelet and plasma proteome profiles of patients with uremia in comparison with healthy participants. It was found that 23 peptides in the platelet proteome profiles of hemodialyzed patients and only 6 peptides in nondialyzed patients were upregulated. On the other hand, 18 pep...

The blood platelet proteome of hemodialyzed patients with uremia exhibits significant difference in comparison with the blood platelet proteome of healthy individuals. This alteration is manifested by the presence of high concentrations of low-molecular peptides within the whole range of isoelectric points. Increased platelet apoptosis has been put...

Titanium alloys are still on the top list of fundamental materials intended for dental, orthopedics, neurological, and cardiovascular implantations. Recently, a special attention has been paid to vanadium-free titanium alloy, Ti6Al7Nb, that seems to represent higher biocompatibility than traditional Ti6Al4V alloy. Surprisingly, these data are not t...

For Abstract see ChemInform Abstract in Full Text.

We demonstrate here for the first time the relationship between electron work function of metallic substrate material, used for coating with thin dielectric carbon (DC) film, and surface thrombocompatybility of this structure. Thin dielectric layers of DC, with thickness below 1 microm, were deposited on medical steel 316L, titanium alloy Ti6Al4V a...

Endogenous mu-opioid receptor (MOR) selective peptides, endomorphin-1 (EM-1) and endomorphin-2 (EM-2), unlike so called 'typical opioids', are characterized by the presence of Pro(2) residue, which is a spacer connecting aromatic pharmacophoric residues. In order to investigate structural requirements for position 2, we synthesized endomorphin anal...

The phenomenon of micron-sized diamond particle uptake by human endothelial cells was demonstrated using microscopic methods including optical microscopy and both scanning and transmission electron microscopy techniques. The study was performed with monocrystalline synthetic diamond powder, ca. 1 μm, and the EA.hy 926 cell line. It was established...

Microscopic methods usable for sample surface imaging and subsequent qualitative and quantitative evaluation of platelet adhesion to the surface of the biomaterial studied were compared. It was shown, making use of the samples of medical steel (AISI 316L), that such tools as surface imaging with scanning electron microscopy (SEM), glutaraldehyde in...

The aim of the present work was to examine the interactions of parylene C with such selected biological objects as: blood plasma proteins, platelets, endothelial cells, and bacterial biofilm produced by E. coli cells. The results obtained strongly support the thesis that parylene C is a material worth considering for biomedical use. Parylene C coat...

Titanium dioxide (TiO2) can be used as protective and biocompatible coatings. Properties of these coatings strongly depend on a method and conditions of the deposition process. The aim of this study was to investigate the contact of whole blood with sol-gel TiO2 films deposited on stainless steel (316L) substrates by the dip–coating method and trea...

Hydroxyapatite (HAp – Ca10(PO4)6(OH)2) and tricalcium phosphate (TCP – Ca3(PO4)2) are bioceramic materials of special interest with regards to bone surgery, in particular the repair of bone tissue defects. These materials are highly biocompatible with bone and soft tissue; they are bioactive, osteoconductive and resistant to sterilisation processes...

Silicone-urethanes, polymers combining the characteristics of two widely used biomaterials, i.e. polyurethanes and silicones, are highly valued in many applications, including medical implants. To assess properties of these materials in contact with living cells, a set of different silicone-urethane materials, candidates for tissue engineering scaf...

Comparative analysis of the protein profile of blood platelets isolated from nondialyzed and hemodialyzed uremic patients and healthy controls has been performed. These preliminary results indicate markedly changed expression of several proteins in blood platelets from both groups of patients compared with controls, with dramatic changes in hemodia...

The experimental procedures were undertaken in order to characterize of surface-modified metallic substrates. Results revealed that carbon layers coating the substrates made metallic surface generally more biocompatible and more resistant to biofilm formation. Titanium-nitride or titanium carbo-nitride layers on the titanium alloy (Ti6Al4V) allow f...

The unique properties of thin diamond layers make them perspective candidates for producing advanced micro-electronic devices, coatings for cutting tools and optics. However, due to the highest biocompatibility of carbon resulting from the presence of this element in the human body, it appears to be a potential biomaterial.Carbon, especially in the...

The stainless steel (AISI 316L) and nanocrystalline diamond (NCD) deposited on stainless steel substrates by Radio Frequency Plasma Chemical Vapour Deposition (RF PCVD), predicted for use as coatings for medical applications, were studied by a meaning of blood platelet adhesion. After 12 h contact with platelet poor plasma (PPP) and additional 1 h...

We attempted to construct a new recombinant protein characterized by fibrin-specific properties of plasminogen activation combined with antithrombin and antiplatelet activities. To the C-terminal part of recombinant staphylokinase (r-SAK), which is a promising profibrinolytic agent, we assembled: (i) the Kringle 2 domain (K2) of tissue-type plasmin...

Susceptibility of medical steel, titanium and medical steel coated with nanocrystalline diamond (NCD) to bacterial colonization was investigated. Number of bacteria at the surface was estimated with fluorescence microscopy inspection. It was found that efficiency of bacterial settlement depends on the presence of proteins in the surrounding media a...

Heat shock proteins (hsp) are known to facilitate the generation of specific immune responses by chaperoning proteins and peptides involved in T cell activation. Hsp have been shown to be strikingly elevated in multiple sclerosis (MS) lesions. The unique chaperonin properties of hsp70 have allowed identification of immunogenic proteins bound to it...

The synthesis and biological evaluation of new diadenosine polyphosphate analogues on blood platelet aggregation are reported. The most active are compounds with a sulfur atom replacing one or both non-bridging oxygens at phosphorus bound to adenosyl residues and hydroxymethyl groups of bis(hydroxymethyl)phosphinic acid.

The plasma membrane Ca(2+)-ATPase in neuronal tissue plays an important role in fine tuning of the intracellular Ca(2+) concentration. The enzyme exhibits a high degree of tissue specificity and is regulated by several mechanisms. Here we analysed the relationship between separate modes of Ca(2+)-ATPase regulation, i.e., reversible phosphorylation...

α1-Acid glycoprotein, one of the major acute phase proteins, was found to interact with plasminogen activator inhibitor type 1 (PAI-1) and to stabilize its inhibitory activity toward plasminogen activators. This conclusion is based on the following observations: (a) α1-acid glycoprotein was identified to bind PAI-1 by a yeast two-hybrid system. Thr...

The use of medical implants allows one to improve patients lives, and quite often it can return patients back to normal activity in their personal and professional lives. One of the most difficult problems, which is necessary to solve, is a proper selection of the materials to be used for implant construction and/or implant coating. The surface of...

Development in thin-layer diamond-like coatings is a very crucial advance in the field of improvement of biomaterial biocompatibility. Owing to their already investigated properties, diamond-like carbon (DLC) and nanocrystalline diamond (NCD) coatings deposited on implants, which are made of materials that can cause undesirable reactions in the org...

Three methods commonly used for isolation of blood platelets from plasma were compared. Platelets were isolated by: 1) a washing method; 2) a method of metrizamide-gradient centrifugation; 3) a modified method of gel-filtration. The last method employed BSA-Sepharose gel instead of routinely used Sepharose gel saturated with BSA. BSA-Sepharose gel...

It has been demonstrated previously that the cardiodepressant activity is present in the bovine hypothalamic extract and in the medium incubating the rat's posterior pituitary lobe "in situ". In this study medium incubating the posterior pituitary lobe was fractionated by a low pressure gel filtration procedure and the cardiodepressant fractions we...

Preliminary results of verapamil uptake into human blood platelets are presented. Fluorescence labeled verapamil (BODIPY-verapamil) was incorporated into blood platelets, and saturation of uptake was observed within 30 minutes. The uptake of BODIPY-verapamil was inhibited by unlabeled one. The number of binding sites is about 2.5 x 105 per platelet...

The inhibition of platelets by some local anaesthetics has been related to the modulation of platelet membrane lipid fluidity, and one of these compounds, procaine, has been proven to be particularly effective inhibitor. In the present study, we examined the effect of procaine on the mobilization of intracellular granule contents in isolated washed...

The aim of the present study was to relate the impairments in calcium mobilization and/or release to the altered membrane dynamics in platelets from patients with type 2 diabetes mellitus. Higher expression of P-selectin (1.4-fold, NS) and the reduction in GPIb alpha expression (by 27.8+/-16.7%, p < 0.0002), as well as the increased fractions of pl...

The aim of the present study was to relate the impairments in calcium mobilization and/or release to the altered membrane dynamics in platelets from patients with type 2 diabetes mellitus. Higher expression of P-selectin (1.4-fold, NS) and the reduction in GPIbα expression (by 27.8 ± 16.7%, p < 0.0002), as well as the increased fractions of platele...

Results of platelet aggregation measured with a dual channel aggregometer and with a microplate reader are compared. Platelets in plasma were activated by ADP and by collagen, and thrombin was used for the aggregation study of gel filtered platelets. The results obtained with both instruments were quantitatively and qualitatively similar. A micropl...

In present investigations, platelet membrane fluidity and intraplatelet Ca2+ mobilization were analysed in uraemic platelets by fluorescence techniques. Thirteen non-dialyzed uraemic patients and 16 control subjects were examined. Anisotropy of DPH-probe, measured at 37 degrees C, was significantly higher in control (0.2236 +/- 0.0050) than in urae...

A new variant of viral haemorrhagic disease of rabbits (VHD) virus, recently detected in Poland and called Blaszki (BLA), gives positive results in enzyme-linked immunosorbent assay (ELISA) and exhibits viral protein of 60 kilodaltons (VP 60), as detected by Western blot analysis. This BLA variant of VHD virus has caused high morbidity and mortalit...

Recently we have described a dependence of platelet disability in thrombosis upon the progression in renal failure and an elevated level of RGDS-containing degradation products in uremic plasma, which is also correlated with progression in renal failure. Based on fluorescence techniques, our present investigations concerned possible changes in plat...

Verapamil is widely used in the treatment of patients with coronary artery disease. The effect of verapamil on vascular smooth muscle cells is well documented. This effect is mediated by the inhibition of calcium fluxes across plasma membranes. Some data suggest that verapamil may affect platelet functions in thrombosis, but those observations were...

The causative agent of viral haemorrhagic disease (VHD) was purified by CsCl and sucrose density gradient from the liver homogenates of rabbits infected with a strain isolated in Poland. Using SDS-PAGE and a western immunoblotting analysis we characterized domestic isolates of VHDV called the BLA and MAL strains and the laboratory isolates KGM and...

The increased nonenzymatic glycosylation of platelet membrane proteins has been suggested to underlie platelet hypersensitivity in diabetes and the relationship of this to the reduced membrane lipid fluidity has been reported. As the modulation in membrane fluidity may determine the degree of accessibility of membrane receptors, the consequent alte...

In diabetic patients, where the membrane lipid microviscosity of blood platelets is altered, the availability of platelet membrane receptors may change concomitantly. Platelet hypersensitivity in diabetic subjects was previously hypothesized to result from the nonenzymatic glycosylation-induced loss in platelet membrane fluidity. In our present stu...

Pig erythrocyte membrane Mg2+-ATPase activity was stimulated by various glutathione S-conjugates. For alkyl S-conjugates, the Km for the stimulation was lower, the more hydrophobic was the conjugate. 2,4-Dinitrophenyl-S-(N-acetyl)cysteine also stimulated the Mg2+-ATPase activity, suggesting a low specificity of the ¿glutathione S-conjugate pump¿. T...

A concentration of protein degradation products containing the RGDS sequence, which could contribute to a lower reactivity of uremic platelets, has been estimated in both uremic (n = 16) and control (n = 7) plasmas. Degradation products and other small molecules were separated from plasma by filtration through AMICON YM-10 filter. RGDS antigen was...

Platelets of uremic patients, activated with ADP, exposed less fibrinogen receptors than control platelets, i.e. 24612 +/- 5541 and 33400 +/- 4302 receptors per platelet, respectively. However, this difference was not statistically significant. When compared with the total number of GPIIb/IIIa complexes, quantified from platelet glycoprotein IIb (G...

Several methodologies used for the identification and characterization of platelet receptors for antiplatelet monoclonal antibodies are compared. Two antiplatelet monoclonal antibodies, are investigated due to their potent effects on human platelet function. A platelet-activating monoclonal antibody, called M.Ab.F11, is able to induce platelet aggr...

The mean platelet volume, measured optically and by the electrical impedance method, was analysed in the patients with chronic renal failure. All parameters describing the circulating platelet biomass except the platelet volume heterogeneity were decreased in these patients. There is a strong inverse relation between the Ivy bleeding time and the p...

The clinical significance of the interaction of antibodies with circulating platelets is well documented, but the mechanisms underlying these interactions are not fully known. Here we describe the characterization of anti-human platelet membrane protein monoclonal antibody (mAb) termed F11. Interaction of mAb F11 with human platelets resulted in do...

Binding of fibrinogen to platelets washed from blood of migraine patients (n = 30) and control donors (n = 24) was compared. In addition, contents of platelet glycoprotein IIb and platelet fibrinogen were determined in both groups by radioimmunoassay. The receptor capacity for fibrinogen in platelets activated by ADP was significantly higher (p les...

A model describing the transport of low molecular weight solutes across cell membranes is presented. The model accounts for many different systems which may mediate the fluxes of various solutes, for the effect of Na+ ions, and for time dependence of the processes. It generalizes the classical three-parameter equation for transport. Solutions to th...

SYNOPSIS In order to determine the platelet characteristics responsible for aggregation, the number and apparent dissociation constant (K D aPP ) of fibrinogen receptors were determined in 12 women with common migraine. The studies were performed by the use of 125 -fibrinogen. The patients were assessed in headache-fee intervals. The mean number of...

Mathematical model of the beta-thromboglobulin (BTG) release from alpha-granules stimulated with ADP is compared with experimental data. Secretion of BTG was analysed using platelets washed by different procedures in the presence or absence of inhibitors of platelet activation. The release of BTG was monitored in response to 5-100 microM ADP. The r...

Mathematical model of the β-thromboglobulin (BTG) release from α-granules stimulated with ADP is compared with experimental data. Secretion of BTG was analysed using platelets washed by different procedures in the presence or absence of inhibitors of platelet activation. The release of BTG was monitored in response to 5–100 μM ADP. The rate constan...

The transport of L-leucine into human blood platelets was characterized as a function of time and amino acid concentration in the medium. Inhibition analyses showed that L-leucine uptake can be only partially inhibited by other amino acids including those which are believed to be transported by the same L system. When Cu2+, Zn2+, Mg2+, Co2+, Fe2+,...