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D Sladowski

Publications and source records attributed to D Sladowski.

13 recordsLinked to original sources
PubMed2005

Culture of the primary corneal epithelium as a potential component of test batteries for eye irritancy testing.

One of the main goals for toxicologists working on the development of in vitro tests is to replace the animal-based eye irritation test. Inflammation is one of the mechanisms which have not been covered sufficiently by the existing in vitro ocular irritancy test systems. As there are major species differences between the human and rabbit eye inflammation mechanisms, the most relevant test system is the human eye itself. The current study focused on an evaluation of the practical availability of human corneal epithelial cells for routine eye irritancy testing. Human corneal epithelium cell cultures were used to assess the effects of lipopolysaccharide on IL-1 beta release. The findings indicated that cytokine release can be augmented by the presence of the complement system, which is normally found in tears. However, the corneal cells were found to be highly resistant to the complement system, which can be attributed to the very high expression of CD59, a powerful complement regulatory protein found in the corneal epithelium. It is estimated that discarded corneas from tissue banks could provide enough material for routine testing by this method.

Animal Testing Alternatives↗
PubMed2001

Preserved tissue allografts in reconstructive surgery.

Results of treatment with three various kinds of allografts: lyophilized bone, deep frozen bone and cartilage preserved in physiological solution, all of them radiation-sterilized are presented. We believe that this presentation may be helpful in estimating the tissue bank's allografts and in establishing indications and contraindications in the application of allografts in surgery.The 'indices of coincidence' were compared in a group of 1014 patients after bone (lyophilized and radiation-sterilized) transplantation. It seems that such a variable as 'rebuilding of graft' may be of prognostic value in analysing the results of treatment in this group.The application of frozen and radiation-sterilized allogenic bone grafts for reconstructions is also described. An analysis of the results of treatment in 1125 patients reveals that the use of preserved bone reduces the extent and duration of surgery. Almost total substitution of grafts may be seen in 3-8 months after surgery.Allogenic, preserved cartilage is often used in facial reconstructions of face. Human costal cartilage, preserved in 0.9% NaCl and radiation-sterilized, was used for reconstruction. The patients were examined 24-190 months after surgery (in several clinical units) and results were collected in a special questionnaire by the team that performed surgery. In an analysed group of 437 patients after cartilage transplantation, 42.2% were operated because of posttraumatical changes, 29.0% because of congenital malformations and in 16.7% non-specific inflammations were the cause of reconstructive operations. Malformations were located mainly in the nose (59%), the ear concha (16.5%) and 10.9% were mandible.The results of treatment were compared with ages of patients, diagnosis and the locations of the changes. Very good results were achieved in 33.5% of the patients, and satisfactory in 41.8% of the patients. However, in 19.9% of the patients the result of treatment was unsatisfactory. Correlation between some clinical and biological characteristics and the result of treatment is under discussion.

Journal Article↗
PubMed2001

In vitro reconstruction of full thickness human skin on a composite collagen material.

Rapid progress of in vitro techniques in the last years enabled the creation of organotypic skin cultures offering new possibilities in wound treatment. Rebuilding of graft is one of the key elements of successful outcome of the procedure. In search for the best scaffold for organotypic skin culture, the novel composite xenogenic collagen based material with unique properties has been created and used to reconstitute full thickness human skin in vitro. Based on our long established technology used for the production of collagen dressings for the treatment of burns, this novel, composite material offers excellent growth support of highly biodegradable spongy layer, combined with mechanical strength of collagen membrane. The modulation of collagen properties was accomplished by consecutive treatment with high temperature and gamma irradiation. The use of the substrate enabled to obtain organotypic culture that resembles full thickness skin with fibroblasts layer and well-developed multilayer epithelium. Our new material offers easy handling of obtained graft during surgery along with accelerated cell growth and controlled biodegradation of the culture support.

Journal Article↗
PubMed2001

Modification of collagen film by certain chemical agents.

Morphological changes and the content of free carboxyl groups in bovine collagen (type I) film under the influence of trypsin, hydrochloric acid (HCl) and ethylenediaminetetraacetic acid (EDTA) were studied. Incubation with trypsin and HCl was found to cause some delamination of the film and the appearance of some low-density spots. Incubation with EDTA did not cause any morphological changes. A high concentration of free carboxyl groups (10-fold higher than in control) was seen after incubation with trypsin.

Animals↗
PubMed2001

In vitro culture of human epithelial cells on a modified xenogenic collagen support.

Human epithelial cells (HeLa, HaCaT, NHK) were cultured in vitro on chemically modified collagen membranes. Adhesion to the support was measured by estimation of the percentage of adhering 51Cr-labeled cells. Proliferation was estimated with the XTT test. Morphological observations of cells growing on HCl-treated collagen were performed using histological and electron microscopic techniques. HCl and trypsin-modified xenogenic collagen was found to be a good support for human cells in vitro. EDTA-incubated collagen enhanced neither adhesion nor proliferation. The best adhesion and proliferation were found on HCl-treated collagen, depending, however, on the kind of cells.

Cell Adhesion↗
PubMed2000

The quality of heart valve tissue for homograft transplantation.

BACKGROUND AND AIM OF THE STUDY: The results of heart valve replacement surgery may be improved by refining surgical techniques and/or developing new heart valve transplants. The aim of this study was to examine the effect of age on the presence of cholesterol clefts and lipid deposits in the cusp base and sinus wall of aortic homografts. METHODS: Seventy-one valves were obtained at autopsy from donors (aged 15- 40 years) with no history of illness or evidence of serious illness. Trauma was the predominant cause of death among patients. The valves were examined using an osmium-vaporization technique. RESULTS: Osmiophilic deposits were detected in the cusp base in 28 cases (42%), and in the sinus wall in 49 cases (69%). Cholesterol crystals in the cusp base were found in 16 cases (24%), and sinus wall cholesterol clefts in 26 cases (38%). The model-predicted probability of cusp base lipid deposits existing was 76% in 40-year-old donors, 36% in 30-years-olds, and 11% in 20-year-olds; the probability of cusp base cholesterol clefts existing was 45%, 21% and 8% in these age groups, respectively. The influences of immunological reactions, biochemical changes (centers of calcification) and acceleration of atherosclerotic processes are discussed. CONCLUSION: The microscopic study of heart valves demonstrated the presence of lipid deposits in subjects of an unexpectedly young age. Among our study material, 58% of valves obtained from donors aged 11-40 years were unsuitable for transplantation. Our results confirmed the need for macroscopic inspection of heart valves before their being transplanted.

Adolescent↗
PubMed1997

Allogenic preserved costal cartilage in reconstructive surgery.

Allogenic, preserved cartilage is often used for reconstruction of face. This study was undertaken to analyze the effects of cartilage transplantation. In analyzed group of 437 patients after cartilage transplantation, 42.2% were operated because of posttraumatical changes, 29.0% because of congenital malformations. In 16.7% nonspecific inflammations were the cause of reconstructive operations. Malformations were mainly localised in nose 59%, ear concha 16.5% and mandible 10.9%. Human costal cartilage, preserved in 0.9% NaCl and radiation-sterilized was used for reconstruction. 24-190 months after surgery (in several clinical units) patients were examined and results were collected in special questionnaire by the team who performed surgery. The results of treatment were compared with age, diagnosis and localisation of changes. It was found that very good result of treatment was achieved in 33.5% of patients, in 41.8% result was satisfactory. In 19.9% of operated patients result of treatment was unsatisfactory. Correlation of some clinical and biological characteristics with the result of treatment is discussed.

Adolescent↗
PubMed1993

An improved MTT assay.

The MTT assay for cell viability and cell proliferation has been modified to improve its reproducibility and accuracy. The modified test is performed on MultiScreen filtration plates, which permits the removal of the culture medium prior to formazan solubilisation, without loss of cells or formazan crystals. A 1:1 mix of DMSO and ethanol is used as the solvent, since this has the same optical refraction index as the filters, making it possible to measure the optical densities directly on the MultiScreen plate. Data obtained in the assay method using the MultiScreen plate were compared with data from studies employing the normal flat-bottomed plate, by using cells which grow in suspension. Two cell lines were used in the study. CTLL-2, which are IL-2 dependent cells of murine T cell origin, and Jurkat E.6.1 which are IL-2 producing cells of human lymphoma origin. CTLL-2 cells and the modified MTT assay were also used for evaluating the effects of different IL-2 concentrations on cell proliferation.

Animals↗
PubMedDate not supplied

Activation of the complement system as an indicator of pyrogenic reaction to lipopolysaccharide (LPS).

The generation of biologically active complement split products through the direct reaction of microorganisms with complement proteins is one of the earliest events of the defence reaction in humans. Complement activation develops within minutes, which highly corresponds with the onset of a febrile reaction after exposure to pyrogens. The possibility of the use of complement activation in human plasma as an indicator of pyrogen contamination has been tested. Additionally, the co-stimulatory effect of complement activation on tumor necrosis factor-alpha (TNF-alpha) production by blood-separated macrophages exposed to lipopolysaccharide (LPS) has been demonstrated. As an indicator of complement activation in test samples, the concentration of the iC3b fragment was measured by using an ELISA system based on neoantigen formation. The 3-h exposure time has been identified as optimal for the test. The variability between iC3b concentrations in untreated control samples obtained from seven unrelated healthy donors was less than 10%, while after activation by 100 ng/ml LPS, it increased to 13%. The lower detection limit has been identified as 10 pg/ml LPS. As the complement test is not affected by drug-cell interactions or cell viability, the test can be used in situations where tested formulations contain active substances, which interfere with a cell-based test. We conclude that a test based on the detection of complement activation in human plasma should be considered as a valuable element of an in vitro pyrogenicity testing battery along with a cell-based assay.

Animal Testing Alternatives↗