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B Dvoránková

Publications and source records attributed to B Dvoránková.

At least 19 recordsLinked to original sources
PubMed2006

Porcine epidermal stem cells as a biomedical model for wound healing and normal/malignant epithelial cell propagation.

This article summarizes research using cells derived from epidermis of the miniature pigs for use as a cell therapy for skin repair and as a model for squamous carcinoma of the head and neck. Stem cells are an important "tool" for biomedical research. Adult stem cells are defined functionally, as cells that have the capacity to self-renew as well as the ability to generate differentiated cells. They are present in defined tissue microenvironments called niches. Asymmetric mitosis allows them to produce one daughter cell with the properties of stem cells (self-renewal) and a second cell with characteristics of progenitor cells, or transit amplifying cells, which proliferate quickly but with a limited number of mitotic divisions. Porcine epidermal stem cells, located in the bulge region of the outer root sheath of hair follicles, migrate in vitro from hair sheaths and because they are resistant to anoikis (detachment induced apoptosis), survive in non-adhesive conditions to form spheroids. These cells express keratins, galectin-1 and their nuclei are rich in DeltaNp63alpha. Interestingly, the multiple phenotype analysis of the human tumor cells in squamous carcinoma of head and neck revealed similarities with epidermal stem cells. These cancer stem cells are usually located on the periphery of the tumor where the invasive front of the tumor responsible for its aggressive behavior is located. In contrast, extensive expression of markers of terminal differentiation such as expression of glycoligands reactive for the endogenous lectin, galectin-3, indicates better tumor prognosis.

Animals↗
PubMed2006

Structural, chemical and biological properties of carbon layers sputtered on polyethyleneterephtalate.

Carbon layers on polyethyleneterephtalate (PET) backing were prepared by sputtering from graphite target. UV-VIS, Raman spectroscopy, RBS (Rutherford backscattering) and ERDA (Elastic Recoil Detection Analysis) techniques were used for the characterization of the layers. Surface morphology of the layers was determined by AFM technique and the adhesion of 3T3 mouse fibroblasts on the layers was studied in vitro. It was found that the properties of the deposited carbon layer depend on the sputtering time. The concentration of conjugated double bonds, fraction of amorphous hydrogenated carbon (a-C:H) containing oxygen and surface roughness are increasing functions of the sputtering time. The changes of the layer surface morphology with increasing sputtering time were also observed. For the sputtering times up to 30' the number of adhering 3T3 cells increases with increasing sputtering time. For longer sputtering times, however, the cell adhesion becomes lower probably due to unfavorable changes in roughness and morphology of the layer.

3T3 Cells↗
PubMed2005

Detection of new diagnostic markers in pathology by focus on growth-regulatory endogenous lectins. The case study of galectin-7 in squamous epithelia.

Lectins represent one of pivotal regulators of the cell proliferation The potential of galectin-7 as a new prognostic marker was studied in normal and transformed squamous epithelia of both ectodermal (epidermis, cornea vs. trichoepithelioma, basal and squamous cell carcinoma) and endodermal (vocal fold epithelium vs. carcinoma) origin. Studies on the cultured cells were also performed. Expression of galectin-7 seems to be connected to the process of stratification, no matter of origin of epithelium. Its expression is significantly reduced in malignant cells, thus galectin-7 might be a differentiation marker of epithelial malignancies.

Biomarkers, Tumor↗
PubMed2004

Decrease of nuclear reactivity to growth-regulatory galectin-1 in senescent human keratinocytes and detection of non-uniform staining profile alterations upon prolonged culture for galectin-1 and -3.

Summary Multipotent stem cells (source for interfollicular epidermis, hairs and sebaceous glands) are localized in the bulge region of the outer root sheath of hair follicles, while stem cells giving rise to interfollicular epidermis reside in its basal. Using the multifunctional lectin galectin-1 as a marker to localize accessible binding sites in situ as a step to figure out galectin functionality in stem cells, we studied hair follicle-derived keratinocytes. Specific nuclear binding of galectin-1 associated with expression of DeltaNp63alpha, a potential marker of epidermal stem cells, was detected. Binding of chimera-type galectin-3 to a nuclear site was not found in parallel assays. During the process of ageing in culture when cells acquire properties of senescence, disappearance of the nuclear signal for galectin-1 binding was accompanied by a similar decrease of nuclear DeltaNp63alpha expression and increased binding of galectin-3 to the cell membrane, namely in regions of intercellular contacts. Expression of cytokeratin 10, a marker of the terminal differentiation was seen only in a small fraction of the cell population. These data extend the evidence for nuclear sites with galectin-1 reactivity in squamous epithelial cells, the expression of which is modulated upon senescence. Moreover, the results document the divergence of galectin-1 and -3 on the level of ligand selection in this cell type, underscoring the importance of the technical aspect to employ tissue lectins as probe and to perform a fingerprinting with several markers of the galectin family in parallel.

Aging↗
PubMed2004

The role of skin bank in the treatment of severely burnt patients.

The accessibility of suitable temporary covers plays the key role in the treatment of severe skin losses. Biological covers have got the longest tradition in the wound healing. Skin banks are engaged in their production and distribution. Already in 1973 J. Moserová developed the methodology of harvesting pig xenografts. Later on, the short-term and the long-term method of storage were verified (Böhm, Konícková, Vogtová). In 1986, the Skin Bank in the Prague Burn Centre was established. In Prague Burn Centre the allografts are used very rarely, usually from the living donors, family members of the patients. Therefore, in our bank, we specialized in harvesting porcine xenografts. They are produced in three different forms--fresh, deep frozen in vapours of liquid nitrogen, and glycerolized. Porcine xenografts serve as a biological cover; they make barrier against infection and evaporation and protect the wound against desiccation. They are used namely for the treatment of superficial burn wounds, as a temporary coverage of excised wounds and as a dressing on release incision. Every year more than 10,000 strips have been used in our Burn Centre, it represents the area 200 m2. Since 1991 cultivation laboratory has been a part of our Skin Bank. We are interested in cultivation of human epidermal cells--keratinocytes. Cultured epidermal grafts became the first human in vitro prepared tissue, which was successfully transplanted to the patient. For the treatment of deep dermal skin losses we use either autologous keratinocytes, which can create permanent cover, or allogeneic cells, which stimulate spontaneous healing. Cultured keratinocytes are used in the treatment of burnt patients as well as in the trophic defects.

Animals↗
PubMed2003

Cell adhesion on polytetrafluoroethylene modified by UV-irradiation in an ammonia atmosphere.

We report on the modification of polytetrafluoroethylene (PTFE) by exposure to the ultraviolet (UV) light of a Xe(2)*-excimer lamp at a wavelength of 172 nm in an ammonia atmosphere. Typical treatment times were up to 30 min. Subsequently, the samples were grafted with the amino acid alanine from an aqueous solution. The samples were characterized by means of optical transmission spectroscopy, laser-induced fluorescence and contact-angle measurements. We studied the adhesion of rat aortic smooth muscle cells (SMC) and mouse fibroblasts (3T3 cells) to the modified polymer samples using an in vitro technique, where the population density and spread of adhering cells is determined 24 h after seeding by image analysis. For both cell types the exposure of PTFE to UV-light in an ammonia atmosphere resulted in a significant increase in the number of adhering cells and in the size of their spreading area. The grafting with alanine enhanced this effect. Additional experiments with human endothelial cells (HEC) also demonstrated improved adhesion to modified PTFE. Thus, PTFE modified by our method appears to be a promising material for fabrication of artificial vascular prostheses and implants or for cultivation of skin substitutes.

3T3 Cells↗
PubMed2003

Functional consequences of the glycophenotype of squamous epithelia--practical employment.

Squamous epithelia represent a morphologically and differentiation-dependent stratified tissue. The stem cells are located in the bulge region of hair follicles or in the basal layer of interfollicular epidermis and in the limbus of the cornea. This article summarizes the data about the glycobiological aspects of squamous epithelia cell differentiation under physiological as well as pathological conditions in relation to the function of this epithelial tissue. The entries about the LC, Merkel cells and melanocytes are also mentioned. The employment of the described data in the diagnostics of carcinomas derived from this type of epithelium as well as in the cell therapy of skin defects are shown.

Agglutinins↗
PubMed2001

Biological properties of copolymer of 2-hydroxyethyl methacrylate with sulfopropyl methacrylate.

Interaction of organism with non-toxic implanted polymers depends on the physicochemical properties of the implant surface, which influence the adsorption of bioactive proteins and subsequently adhesion and growth of cells. The synthetic hydrogels are known as poorly adhesive surfaces. In this study we demonstrated the adsorption of albumin, fibrinogen, fibronectin, basic fibroblast growth factor, heparin-binding epidermal growth factor-like growth factor and epidermal growth factor to poly(2-hydroxyethyl methacrylate) (pHEMA) and copolymer of 2-hydroxyethyl methacrylate (HEMA) and potassium salt of 3-sulfopropyl methacrylate (SPMAK). The adhesion and growth of 3T3 cells and human keratinocytes on surface of these polymers was tested without and with pretreatment of polymers with heparin-binding epidermal growth factor-like growth factor. The adhesion of mixture of human granulocytes and monocytes to these surfaces was also tested. The strips of both polymers were subcutaneously and intracerebrally implanted into the rat and the extent of foreign body reaction and brain biocompatibility was evaluated. The results showed the extensive adsorption of basic fibroblast growth factor and heparin-binding epidermal growth factor-like growth factor to copolymer containing SPMAK. However the adhesion (and growth) of cells to this type of copolymers was very low. Preadsorption of human plasma to pHEMA clearly stimulated the leukocyte adhesion in contrary to copolymer containing SPMAK. The extent of foreign-body reaction was significantly higher against the pHEMA compared to tested copolymer p(HEMA-co-SPMAK). In conclusion, the tested copolymer was a poorly adhesive substrate that is only poorly recognized by the non-specific immunity, although the adsorption of basic growth factors to this substrate is highly significant. Both polymers were well tolerated by the brain tissue. The phenotype of surrounding neurons was more close to the control neurons in the brain tissue surrounding the p(HEMA-co-SPMAK) implants.

Journal Article↗
PubMed2001

Postmitotic basal cells in squamous cell epithelia are identified with Dolichos biflorus agglutinin--functional consequences.

Dolichos biflorus agglutinin (DBA) is a plant lectin specifically recognizing alpha-N-acetylgalactosamine. Controversial reports regarding the binding of DBA to the epidermis have been published. Using a double labeling procedure at the single-cell level, we studied the expression of DBA-reactive binding sites in conjunction with markers of cell proliferation and differentiation in normal human epidermis, cornea, and malignant tumors as well as in cultured keratinocytes. The results characterize the cells recognized by DBA as postmitotic early differentiating cells, identifiable by their lack of expression of the proliferation marker (Ki-67). The Golgi complex of a limited number of cultured keratinocytes was recognized by DBA and some of these cells show the accumulation of beta1 integrin chain in the Golgi complex. This process seems to be important for the migration of postmitotic cells from the basal to the suprabasal layers.

3T3 Cells↗
PubMed2001

Cells of porcine epidermis and corneal epithelium are not recognized by human natural anti-alpha-galactoside IgG.

Human natural antibodies against Galalphal,3Gal-R are mainly responsible for hyperacute rejection of xenografts transplanted to the human host. In addition to the anti-alpha-Gal activity, human serum also contains anti-beta-Gal IgG fractions. Employing biotinylated IgG subfractions with anti-alpha- and anti-beta-Gal activity purified from human natural IgG, we have studied expression of reactive epitopes in porcine and human skin, porcine cultured keratinocytes and porcine and human cornea, porcine liver and human lacrimal gland, tear fluid and capillaries. No reactivity of porcine and human epidermis as well as anterior corneal epithelium was observed for human anti-alpha-Gal IgG. Serving as positive control, porcine capillaries gave the expected signal with the anti-alpha-Gal antibody. The anti-beta-Gal subfraction recognized cell nuclei in the epidermis of both these species. The pig liver cells interacted with antibodies against alpha- and beta-galactosides like cells of the human lacrimal gland. alpha-galactoside-reactive glycoproteins were also detected in the human tear fluid. The carbohydrate specificity of the reaction was ascertained by using melibiose as competitive sugar for alpha-galactoside-mediated binding. These results reveal the presentation of Galalpha1,3Gal in epithelial cells of human lacrimal gland, its biosynthetic origin being unclear. With respect to a potential clinical perspective, the given results facilitate consideration of the use of porcine epidermal cells in engineering of non-permanent wound covers to improve treatment.

Animals↗
PubMed2000

Adhesion and proliferation of keratinocytes on ion beam modified polyethylene.

Polyethylene (PE) foils were modified by irradiation with Ar+ and Xe+ ions to different fluences and different physico-chemical properties of the irradiated PE were studied in relation to adhesion and proliferation of keratinocytes on the modified surface. Changes in the PE surface roughness were examined using the AFM technique, the production of conjugated double bonds and oxidized structures by UV-VIS and FTIR techniques respectively. The surface polarity was determined by measuring surface contact angle and two-point technique was used for the determination of PE sheet resistance. Adhesion and proliferation of keratinocytes was characterized using the MTT-test. The ion irradiation leads to creation of conjugated double bonds which, together with progressive carbonization, contribute to the observed decrease of sheet resistance. Oxidation of the irradiated PE surface layer during the ion implantation is observed. Besides oxidation, the PE surface polarity is affected by other factors. The observed increase of the PE surface roughness due to the ion irradiation is inversely proportional to the ion size. The adhesion and proliferation of keratinocytes on the ion irradiated PE is significantly higher than on the pristine PE. Distribution of results in keratinocyte cultivation and the number of cells is related to the ion fluence applied and to ion species as well.

Journal Article↗
PubMed2000

Human epidermal Langerhans cells are selectively recognized by galectin-3 but not by galectin-1.

Langerhans cells are dendritic antigen-presenting cells residing predominantly in the epidermis. Since endogenous galactoside-binding lectins with the jelly-roll motif (galectins) are known to trigger cellular responses, including mediator release, we investigated by lectin histochemistry the cells' capacity to bind two common members of this family, i.e. galectin-1 and -3. Actually, surrounding keratinocytes express a high level of galectin-3, and these cells can be considered as donors of this lectin to Langerhans cells. Employing biotinylated galectin-1 and -3, and concomitantly an antibody against CD1a as a second marker, to visualize the position of Langerhans cells in the human epidermis, the expression of galectin-3-reactive glycoligands in contrast to the lack of binding of galectin-1 was observed. Although the functional consequences of this selectivity are unclear, these results reveal an example for differential cellular reactivity towards two related endogenous lectins.

Adult↗
PubMed1999

Coexpression of binding sites for A(B) histo-blood group trisaccharides with galectin-3 and Lag antigen in human Langerhans cells.

Galectin-3 is an immunomodulatory protein with binding capacity for various glycoconjugates including IgE. It has been shown to be produced by epidermal keratinocytes and is present on the surfaces of skin Langerhans cells (LC). Therefore, it may have a role in the pathogenesis of various skin diseases, such as atopic dermatitis. To study the expression of galectin-3 in LC, we used, in addition to specific antibodies, a panel of synthetic, carrier-immobilized, specific oligosaccharides of the A- and B-histo-blood group, which are recognized by this lectin. In the mean time, Birbeck granules were visualized with an anti-Lag antibody. The double labeling experiments showed a remarkable colocalization of signals for Lag antigen (Birbeck granules) and galectin-3, as well as the binding sites for A- and B-histo-blood group trisaccharides. The specificity of the oligosaccharide binding was demonstrated by the lack of binding by Le(c), Le(d) (H blood group antigen), and sLe(x), which are not recognized by galectin-3. These results suggest that galectin-3 is present in Birbeck granules, where it retains reactivity for its glycoligands.

ABO Blood-Group System↗
PubMed1997

Silicone rubber-hydrogel composites as polymeric biomaterials. IX. Composites containing powdery polyacrylamide hydrogel.

A composite material has been prepared consisting of a silicone rubber matrix and particulate lightly cross-linked polyacrylamide hydrogel. The material, resembling common silicone rubber, is hydrophilic and swells in water like hydrogels. The polyacrylamide has a high specific surface area, a relatively low content of water-soluble low-molecular-weight compounds and, owing to its non-ionogenic character, a pH-independent swelling degree. For the composite material consisting of the silicone rubber and very fine powdery cross-linked polyacrylamide, we have measured the rate of swelling in water, the mechanical properties (tensile strength, break elongation, hardness, resilience), biological properties (implantation test, cytotoxicity, cell cultivation) and UV absorption of its water extracts. The polyacrylamide and polysiloxane purity, as the composite material starting components, has been determined to be satisfactory. As a result, a high swelling rate of the prepared composite material has been observed, resulting in reaching more than 70% wt of water of the equilibrium swelling. The results show that the composite material is suitable for biological and medical use.

3T3 Cells↗
PubMed1997

Phenotypic characterization of keratinocytes migrated from polymer support - in vitro study.

The keratinocytes are able to migrate from the poly (2- hydroxyethylmethacrylate) disc if it is transferred to the new Petri-dish colonized with irradiated 3T3 mouse fibroblasts, and form a ring-shaped colony around the disc. The phenotypic characterization of human keratinocytes migrated from these discs was studied using a group of monoclonal antibodies. The keratinocytes in the external periphery of the colony of cells which migrated from the disc express the proliferating cell nuclear antigen (PCNA), alpha2, alpha3 chains and alpha5beta1 integrin receptor. A protein of the desmosome complex, desmoplakin-1, was also expressed. Involucrin and cytokeratin-10 were expressed after prolonged cultivation. These results suggest that the migrated keratinocytes are able to proliferate, recognize extracellular matrix molecules important in the process of the re-epitelization of the wound, and terminally differentiate in vitro. They are encouraging for further experiments with respect to the development of a support for keratinocyte cultivation and for grafting in clinical practice.

Journal Article↗
PubMed1996

Cultivation of keratinocytes on poly HEMA and their migration after inversion.

This study demonstrates how the pretreatment of poly HEMA disks with bovine serum influences the adhesion of human keratinocytes in vitro. The ability of these cells to migrate from poly HEMA disks to a polystyrene petri dish surface colonized with irradiated 3T3 cells is also evaluated. The stimulatory effect of 24-h preincubation of the poly HEMA disks with bovine serum on the keratinocyte adhesion and growth was dependent on the concentration of the serum used. The keratinocytes migrated from the poly HEMA disks to polystyrene colonized with irradiated 3T3 cells. The numerous cells which migrated from the poly HEMA were positive for cytokeratin 10 (suprabasal layers) after 3 weeks and for cytokeratin 1 (cornified layer) after 1 month. These results seem to be encouraging for further experiments with respect to clinical application.

Animals↗
PubMed1994

Metabolic activity of cultured skin grafts cryopreserved in different forms.

Cultured epidermal cells in the form of coherent sheets have been used for the treatment of skin defects. Metabolic activity of fresh and in liquid nitrogen cryopreserved keratinocyte suspensions and three forms of coherent cultured skin sheets were compared with the aim to find the most appropriate form of skin cultures for cryopreservation. Keratinocytes cultured from cryopreserved suspensions formed a confluent layer in 8-10 days after thawing, showing 95% activity of the fresh confluent cultures. Cryopreserved cultured epidermal sheets attached to the bottom of the dish as well as recombined human/pig skin (RHPS) reached more than 70% of the metabolic activity of fresh grafts following 24 h regeneration in the incubator after thawing. Cultured epidermal sheets detached from the dish and mounted on tulle grass reached only 28% of the fresh graft metabolic activity under the same conditions.

Animals↗