Biomedical subjects
Uta-Christina Hipler
Publications and source records attributed to Uta-Christina Hipler.
Antimycotic influence of beta-cyclodextrin complexes--in vitro measurements using laser nephelometry in microtiter plates.
To determine the in vitro susceptibility of fungal organisms to beta-cyclodextrin (CD) complexes with the antifungal agents econazole-nitrate (EC) and ciclopirox-olamine (CI), a fast, rapid and simple method using laser nephelometry in 96-microtiter plate is used. The antimycotic influence of the complexes against Candida albicans DSM 11225 and Candida krusei ATCC 6258 species was determined using this method. A rapid inhibition and even killing of both fungi was observed only above certain concentrations of complex ranged between 12.5 and 100 microg/ml for beta-CD-econazole complex (CD-EC), while for the complex with ciclopirox-olamine (CD-CI) the range was between 150 and 400 microg/ml. The stability constants of the CD complexes with the two antimycotic derivatives are given. In addition, the nephelometric method allows the determination of solubilities of active agents. Thus, the improvement of solubility of both antimycotic agents in PBS buffer solution was observed by complexation with CD.
Antifungal and antibacterial properties of a silver-loaded cellulosic fiber.
The skin is the interface between the body and the environment. Each skin type has a specific skin physiology and is more or less adapted for protection against multiple stress factors. Textiles on the other hand are the tissues with the longest contact to the human skin. They play a critical role especially in skin conditions with an increased rate of bacterial and fungal infections like atopic dermatitis and hyperhidrosis, and in diabetic patients and aged skin. The present study demonstrates the antifungal and antibacterial effects of SeaCell Active in an in vitro test system against Candida albicans (DSM 11225), Candida tropicalis (ATCC 1169), and Candida krusei (ATCC 6258). Furthermore, the antibacterial activity of fibers with different amounts of SeaCell Active fibers in a dose-dependent manner against Staphylococcus aureus (ATCC 22923) and Escherichia coli (ATCC 35218) could be demonstrated. If this fiber seems to be suited for bioactive textiles in specific anatomical regions and skin conditions with a susceptibility for fungal and bacterial infections due to Candida species, namely Staphylococcus aureus and Escherichia coli, must be examined by means of further investigations, especially in vivo tests in human, considering allergic and toxic effects of the fiber.
Cyclodextrin-induced apoptosis in human keratinocytes is caspase-8 dependent and accompanied by mitochondrial cytochrome c release.
Cyclodextrins (CDs) are cyclic oligosaccharides that are able to form inclusion complexes with a variety of substances. For pharmaceutical applications, CD-based drug formulations offer important advantages compared with uncomplexed drugs. These include improved water solubility of lipophilic drug molecules, increased chemical stability, as well as enhanced bioavailability and absorption rate. Also, a number of topical formulations for dermal and transdermal drug delivery contain CDs. However, the most frequently used CDs - beta-CD and MbetaCD - are known to extract cholesterol from plasma membranes and thus to cause cellular damage and cell death. In the present study, the influence of various CDs and CD derivatives on the human keratinocyte cell line HaCaT was assessed. We found that beta-CD and MbetaCD induce apoptosis via the activator caspase-8, which subsequently activates the effector caspases-3/-7. Furthermore, beta-CD-induced apoptosis is accompanied by mitochondrial cytochrome c release. A significant shift from mitochondria into the cytosol was found. These findings may provide further rationale to the use of CDs in topical formulations for dermal and transdermal drug delivery or as raw material in order to functionalize textiles for medical applications.
A new silver-loaded cellulosic fiber with antifungal and antibacterial properties.
The skin is the interface between the body and the environment. Each skin type has a specific skin physiology and is more or less adapted for protection against multiple stress factors. Textiles on the other hand are the tissues with the longest contact with the human skin. They play a critical role especially in skin conditions with an increased rate of bacterial and fungal infections like atopic dermatitis or hyperhidrosis, diabetic patients and aged skin. The present study demonstrates the antifungal and antibacterial effect of Sea Cell(R) Active in an in vitro test system against Candida albicans (DSM 11225), Candida tropicalis (ATCC 1169) and Candida krusei (ATCC 6258). Furthermore, the antibacterial activity of fibers with different amounts of Sea Cell Active fibers could be demonstrated in a dose-dependent manner against Staphylococcus aureus (ATCC 22923) and Escherichia coli (ATCC 35218). Whether this fiber seems to be suited for bioactive textiles in specific anatomical body regions and skin conditions with a susceptibility to fungal and bacterial infections, namely Candida species, S. aureus and E. coli, must be examined by means of further investigations, especially human in vivo tests considering allergic and toxic effects of the fiber.
Influence of selected wound dressings on PMN elastase in chronic wound fluid and their antioxidative potential in vitro.
Exudates from non-healing wounds contain elevated levels of proteolytic enzymes, like elastase from polymorphonuclear granulocytes (PMN elastase), reactive oxygen species (ROS) and reactive nitrogen species (RNS). The overproduction of proteolytic enzymes leads to reduced concentrations of growth factors and proteinase inhibitors, resulting in an imbalance between degradation and remodelling processes. Thus, the reduction of protein-degrading enzymes and scavenging of ROS and RNS seem to be suitable ways to support the healing process of chronic stagnating wounds. The aim of this study was to test selected wound dressings from different biomaterials (collagen, oxidized regenerated cellulose (ORC) and ORC/collagen mixture), regarding their antioxidative potential in vitro and their influence on the concentration and activity of PMN elastase in chronic wound fluid. Antioxidant capacity of the investigated wound dressing was determined by a pholasin-based chemiluminescent assay. PMN elastase concentration was determined by means of ELISA. Enzyme activities could be measured by a fluorescence assay. As the presented data demonstrates, all tested materials showed antioxidant capacity. In addition, the investigated materials were able to reduce the concentration and activity of PMN elastase. Beside other aspects, such as biocompatibility, biodegradability, fluid absorption and clinical effects (e.g. angiogenesis and microcirculation), the understanding of these properties may help to support the further refinement of wound dressings for improved wound healing.
Melatonin suppresses reactive oxygen species induced by UV irradiation in leukocytes.
An investigation of the antioxidative UV protective effect of melatonin was performed in an in vitro irradiation model with leukocytes. Leukocytes were isolated from EDTA-treated whole blood and taken up in phosphate-buffered saline (PBS). Five of 10 aliquots were incubated with 2 mmol/L melatonin and 5 with PBS as a control. The samples were irradiated by UV light (280-360 nm, max: 310 nm) at doses between 75 and 300 mJ/cm(2) or left unirradiated. Radical formation was measured using the chemiluminescence technique. Staining with trypan blue was performed to assess cell viability. Melatonin significantly suppressed radical formation in cell solutions irradiated from 75 to 300 mJ/cm(2) (P </= 0.001). Controls showed an increase of reactive oxygen species (ROS) formation as a sign of oxidative stress when irradiated with increasing UV doses and a maximum ROS formation under 300 mJ/cm(2) UV light. The cytotoxicity of UV light was reduced by melatonin up to a UV dose of 1.5 J/cm(2). Leukocytes were suitable cells for the evaluation of the efficacy of melatonin as a radical scavenger under UV light. The results confirm that the clinically observed UV protective effects of melatonin may be at least partially based on its radical scavenging properties.
Case report. Monascus purpureus--a new fungus of allergologic relevance.
Anaphylactic reactions to food containing allergens in the consumption or preparation of food are well known. However, allergy in the preparation of sausages has rarely been described. In the present study a 26-year-old-butcher was investigated who had a severe anaphylactic reaction developing sneezing, rhinitis, conjunctivitis, generalised pruritus, followed by widespread urticaria, Quincke's oedema and dyspnoe after starting to prepare sausages containing red yield rice. Red yield rice is produced by the fungus Monascus purpureus. It was the first time that Monascus purpureus could be shown as allergic agent by means of prick-to-prick test, Cellular Antigen Stimulation Test (CAST) and different immunoblots.
Melatonin suppresses reactive oxygen species in UV-irradiated leukocytes more than vitamin C and trolox.
To prove the relative potency of melatonin as a radical scavenger in UV-irradiated leukocytes, it was compared to other antioxidative substances such as trolox and vitamin C. Human leukocytes were isolated from EDTA whole blood and incubated with melatonin, trolox and vitamin C. The experiments were performed in a wide concentration range from 0.1 nM to 1 mM and in a small concentration range from 0.5 to 2 mM (mel), 5 mM (trolox) and 10 mM (vit. C). Irradiation was performed with UV-light (280-360 nm) at a dose of 750 mJ/cm(2). Radical formation was measured by the chemiluminescence technique. The maximum effect of radical suppression was seen at a concentration of 10 nM (p = 0.003) and 1 mM melatonin (p < 0.001) and vitamin C (p = 0.002; p < 0.001), respectively. ROS suppression by trolox was only significant at 1 mM (p < 0.001). In the small concentration range, a linear dose-response relationship was found and melatonin showed the strongest radical suppression (IC(50) = 0.21 mM) followed by vitamin C (IC(50) = 0.26 mM) and trolox (IC(50) = 1.03 mM).