sodium-dodecyl-sulfate and Corneal-Diseases

Trichosporon asahii is a conditional pathogenic fungus that causes severe and sometimes fatal infections in immunocompromised patients. While calcineurin, an essential component of a calcium-dependent signaling pathway, is known to regulate stress resistance and virulence of some pathogenic fungi, its role in T. asahii has not been investigated. Here, we demonstrated that calcineurin gene-deficient T. asahii mutants are sensitive to high temperature as well as cell-membrane and cell-wall stress, and exhibit decreased hyphal formation and virulence against silkworms. Growth of T. asahii mutants deficient in genes encoding subunits of calcineurin, cna1 and cnb1, was delayed at 40 °C. The cna1 and cnb1 gene-deficient mutants also showed sensitivity to sodium dodecyl sulfate, Congo red, dithiothreitol, and tunicamycin. On the other hand, these mutants exhibited no sensitivity to caffeine, sorbitol, monensin, CaCl

Topics: Amphotericin B; Antifungal Agents; Basidiomycota; Caffeine; Calcineurin; Calcium; Calcium Chloride; Congo Red; Cornea; Corneal Diseases; Dithiothreitol; Eye Diseases, Hereditary; Fluconazole; Monensin; Sodium Chloride; Sodium Dodecyl Sulfate; Sorbitol; Trichosporon; Tunicamycin; Virulence; Voriconazole

Corneal dystrophies are genetic disorders resulting in progressive corneal clouding due to the deposition of amyloid fibrils derived from keratoepithelin, also called transforming growth factor β-induced protein (TGFBI). The formation of amyloid fibrils is often accelerated by surfactants such as sodium dodecyl sulfate (SDS). Most eye drops contain benzalkonium chloride (BAC), a cationic surfactant, as a preservative substance. In the present study, we aimed to reveal the role of BAC in the amyloid fibrillation of keratoepithelin-derived peptides in vitro. We used three types of 22-residue synthetic peptides covering Leu110-Glu131 of the keratoepithelin sequence: an R-type peptide with wild-type R124, a C-type peptide with C124 associated with lattice corneal dystrophy type I, and a H-type peptide with H124 associated with granular corneal dystrophy type II. The time courses of spontaneous amyloid fibrillation and seed-dependent fibril elongation were monitored in the presence of various concentrations of BAC or SDS using thioflavin T fluorescence. BAC and SDS accelerated the fibrillation of all synthetic peptides in the absence and presence of seeds. Optimal acceleration occurred near the CMC, which suggests that the unstable and dynamic interactions of keratoepithelin peptides with amphipathic surfactants led to the formation of fibrils. These results suggest that eye drops containing BAC may deteriorate corneal dystrophies and that those without BAC are preferred especially for patients with corneal dystrophies.

Topics: Amyloid; Benzalkonium Compounds; Corneal Diseases; Detergents; Extracellular Matrix Proteins; Humans; Ophthalmic Solutions; Peptides; Sodium Dodecyl Sulfate; Transforming Growth Factor beta

Calcific band keratopathy (CBK) is a degenerative condition resulting in the deposition of calcium salts in the superficial layers of the cornea and causing significant visual disturbance and pain of the affected eye. Unfortunately, the amount of CBK precipitates recovered from the affected eye is very small therefore; it would be beneficial to prepare a synthetic material mimicking CBK material to further the development of therapeutics. Analyses of biological samples recovered from patients show the presence of silicon in addition to calcium, as well as a distinctive fused spherical morphology. This prompted us to study the reaction of various sources of silicon (fumed silica, silicic acid, and silicone oil) with CaCO(3) under a range of reaction conditions to gain an understanding of the formation of CBK. A silicon source alone was not found to be responsible for the fused spherical morphology, and a third component, a polar surfactant-like molecule such as sodium dodecyl sulfate or tetradecylphosphonic acid, was also required. The effects of silicon:calcium ratio and reaction time have been studied. The reaction of fumed silica with CaCO(3) in presence of sodium dodecyl sulfate results in the formation of spherical shapes resembling the structures and chemical composition observed in the eye samples, while no such structures were observed in the absence of silicon. Samples closely resembling human samples were also formed from the reaction of silicone oil with CaCO(3) in the presence of tetradecylphosphonic acid. Samples were characterized by SEM, XRD, and XPS and Raman spectroscopy.

Topics: Alkanes; Biocompatible Materials; Calcinosis; Calcium Carbonate; Corneal Diseases; Humans; Materials Testing; Molecular Structure; Organophosphonates; Phosphorous Acids; Silicic Acid; Silicon; Silicon Dioxide; Sodium Dodecyl Sulfate; Surface-Active Agents

The aim of this study was to investigate high-molecular-weight hyaluronan (HA-HMW) corneal protection against sodium lauryl sulfate (SLS)-induced toxic effects with in vitro and in vivo experimental approaches.. In vitro experiments consisted of a human corneal epithelial cell line incubated with HA-HMW, rinsed, and incubated with SLS. Cell viability, oxidative stress, chromatin condensation, caspase-3, -8, -9, and P2X7 cell death receptor activation, interleukin-6, and interleukin-8 production were investigated. In vivo experiments consisted of 36 New Zealand white rabbits treated for 3 days, 3 times per day, with HA-HMW or phosphate-buffered salt solution. At day 4, eyes were treated with SLS. Clinical observation and in vivo confocal microscopy using the Rostock Cornea Module of the Heidelberg Retina Tomograph-II were performed to evaluate and to compare SLS-induced toxicity between eyes treated with HA-HMW and eyes treated with phosphate-buffered salt solution.. In vitro data indicate that exposure of human corneal epithelial cells to HA-HMW significantly decreased SLS-induced oxidative stress, apoptosis, and inflammation cytokine production. In vivo data indicate that SLS cornea injuries, characterized by damaged corneal epithelium, damaged anterior stroma, and inflammatory infiltrations, were attenuated with HA-HMW treatment.. A good correlation was seen between in vitro and in vivo findings showing that HA-HMW decreases SLS-induced toxic effects and protects cornea.

Topics: Animals; Apoptosis; Caspases; Cell Line; Cell Survival; Chromatin; Corneal Diseases; Cytoprotection; Epithelium, Corneal; Humans; Hyaluronic Acid; Interleukins; Male; Microscopy, Confocal; Molecular Weight; Oxidative Stress; Rabbits; Receptors, Purinergic P2; Receptors, Purinergic P2X7; Sodium Dodecyl Sulfate; Viscosupplements

An ocular irritation test in the mouse has been developed, in which corneal lesions consecutive to instillation of ophthalmic preparations are assessed by digital image processing. The high sensitivity of this method makes it possible to test very low (i.e. therapeutic) concentrations, which do not produce macroscopic damage to the eye. The relatively low variability of the results allows the determination of irritation potential with a small number of animals. The test permits the establishment of the relationship between instilled concentrations and corneal lesions. The rapidity and simplicity of this approach make the proposed test suitable for the screening of ophthalmic preparations.

Topics: Animals; Benzalkonium Compounds; Corneal Diseases; Image Processing, Computer-Assisted; Mice; Ophthalmic Solutions; Sodium Dodecyl Sulfate; Tetracaine; Video Recording