A Promising Antifungal and Antiamoebic Effect of Silver Nanorings, a Novel Type of AgNP.

Silver nanoparticles (AgNPs) play an important role in the medical field due to their potent antimicrobial activity. This, together with the constant emergence of resistance to antimicrobial drugs, means AgNPs are often investigated as an alternative to solve this problem. In this article, we analyzed the antifungal and antiamoebic effects of a recently described type of AgNP, silver nanorings (AgNRs), and compared them with other types of AgNPs. Tests of the activity of AgNPs against various fungal and amoebic species were carried out. In all cases, AgNPs showed a high biocidal effect, although with fungi this depended on the species involved. Antifungal activity was detected by the conditioning of culture media or water but this effect was not dependent on the release of Ag ions. On the other hand, the proliferation of Acanthamoeba castellanii trophozoites was reduced by silver nanorings (AgNRs) and silver nanowires (AgNWs), with AgNWs being capable of totally inhibiting the germination of A. castellanii cysts. AgNRs constitute a new type of AgNP with an antifungal and antiacanthamoebic activity. These results open the door to new and effective antimicrobial therapies as an alternative to the use of antifungals or antiamoebic drugs, thus avoiding the constant appearance of resistance and the difficulty of eradicating infections.

Bacteria associated with acne use glycosaminoglycans as cell adhesion receptors and promote changes in the expression of the genes involved in their biosynthesis.

BACKGROUND: Cell surface glycosaminoglycans (GAGs) participate in many physiological and pathological processes, including infections and inflammatory response. Acne is a common chronic inflammatory skin disorder that affects the pilosebaceous unit and has a multifactorial etiology, including bacterial colonization of the hair follicle. This study aimed to investigate the participation of GAG in the adhesion of Propionibacterium acnes, Staphylococcus aureus and Staphylococcus epidermidis to keratinocytes and fibroblasts of the skin by competition experiments and cell surface removal using specific liases. The alteration in the transcription of the genes responsible for the synthesis of GAG induced by the adhesion of these bacteria was also analyzed by qRT-PCR. RESULTS: GAGs are involved in bacterial adherence to skin cells, especially fibroblasts, where chondroitin sulfate displayed the higher effect. Bacterial adherence produced different alterations in the transcription of the genes responsible for GAG structures. P. acnes induced mostly changes in keratinocytes, while S. epidermidis was the main cause of alterations in fibroblasts. These variations in gene expression affected all the stages in the biosynthesis of the main species of GAGs, heparan and chondroitin sulphate. CONCLUSIONS: GAGs species are involved in the adhesion of acne-related bacteria to skin cells in a differential manner depending on each microorganism and cellular type, although other receptors seem to exist. Bacterial adherence led to variations on gene expression in skin cells affecting GAG chains structure what, consequently, should alter their interactions with different ligands, affecting the development of acne disease.

The Genes Encoding Small Leucine-Rich Proteoglycans Undergo Differential Expression Alterations in Colorectal Cancer, Depending on Tumor Location.

Small leucine-rich proteoglycans (SLRPs) regulate different processes and undergo significant alterations in various diseases. Colon carcinomas (CCs) are heterogeneous pathologies with important clinical and molecular differences depending on their location, which makes it interesting to analyze the alterations in SLRPs in right- and left-sided tumors (RS- and LSCCs). SLRP transcription levels were studied in 32 CCs using qPCR compared to healthy colon mucosae samples from the same patients, 20 of them from LSCCs and the remaining 12 from RSCCs. Protein expression of genes with significant differences in their transcriptions was analyzed by immunohistochemistry. The alterations observed were related to survival data. The arrangement of transcription of SLRPs was quite similar in ascending and descending colon, but RS- and LSCCs displayed different patterns of alteration, with a greater number of deregulations occurring in the latter. The analysis of protein expression also indicated changes in the location of these molecules, largely moving to the cell interior. While podocan underexpression showed a trend toward better outcomes, no differences were observed in terms of overall survival. In vitro studies using the HT29 tumor cell line suggest that deregulation of SLRPs could affect cell proliferation. SLRPs constitute new differential markers of RS- and LSCCs, showing differences dependent on the anatomical location of the tumor.

Alterations in the Expression of the Genes Responsible for the Synthesis of Heparan Sulfate in Brains With Alzheimer Disease.

The saccharide chains of heparan sulfate appear to be involved in several aspects Alzheimer disease (AD) pathogenesis. Their structural complexity is due to the expression of different isoenzymes. We studied the differential transcription of heparan sulfate chain biosynthesis in AD brains, analyzing different brain regions in patients with different extents of AD pathology. The transcriptomic study was performed by RT-PCR using samples of amygdala, anterior hippocampus, posterior hippocampus, claustrum, calcarine fissure, globus pallidus and cerebellum from patients with mild, moderate, or severe AD, as well as healthy individuals. Certain heparan sulfate epitopes were also detected by immunohistochemistry. Several genes, across all stages of heparan sulfate synthesis, showed altered transcription in different brain regions of AD patients. The numbers of alterations were greater in in moderate versus mild AD patients. In severe patients, there were fewer alterations in genes related to early stages of biosynthesis, and overexpression of genes involved in late stages. The alterations correlated with progressive brain atrophy, although alterations were more common in the cerebellum. Detection of some heparan sulfate epitopes by immunohistochemistry was consistent with previous studies. In conclusion, transcriptional alterations in the biosynthetic genes of heparan sulfate depend on the brain region and the degree of AD pathology.

Use of autologous plasma rich in growth factors fibrin membrane in the surgical management of ocular surface diseases.

PURPOSE: To evaluate the safety and efficacy of the surgical use of autologous plasma rich in growth factors fibrin membrane (mPRGF) in improving corneal wound healing and regeneration in a variety of complex ocular surface defects. METHODS: Chart review on 15 eyes of 14 included patients undergoing ocular surface intervention using intraoperative mPRGF at the Bascom Palmer Eye Institute and at the Instituto Oftalmológico Fernández-Vega was performed. Patients were grouped based on type of intervention or condition (penetrating keratoplasty, superficial keratectomy, neurotrophic or persistent corneal ulcers, and corneal perforation). Patients were followed for an average of 11 ± 5 months. Main outcomes measured were mPRGF dissolving time, best-corrected visual acuity, and evidence of any persistent epithelial defects, rejections, or complications. RESULTS: All 15 eyes underwent successful placement of mPRGF. Average dissolving time for fibrin membrane was 21 ± 3 days. mPRGF resulted in total healing of the corneal defects in 13/15 (86.7%) of the treated eyes and partial healing in 2/15 (13.3%) eyes in which persistent epithelial defects were noted on follow-up. Visual acuity improvement was seen in 9/15 (60%) of the cases. CONCLUSION: The use of autologous mPRGF in the healing and regeneration of the ocular surface is a secure and efficacious surgical option. Our data demonstrate that PRGF fibrin membrane should be contemplated as an important tool to optimize ocular surface regeneration in complex cases.

Plasma Rich in Growth Factors for the Treatment of Ocular Surface Diseases.

PURPOSE: The purpose of this work is to describe and review the technology of plasma rich in growth factors (PRGF), a novel blood derivative product, in the treatment of ocular surface disorders. METHODS: To demonstrate the importance of this technology in the treatment of ocular pathologies, a thorough review of the preclinical and clinical literature results obtained following use of the different therapeutic formulations of PRGF was carried out. A literature search for applications of PGRF plasma in the ophthalmology field was carried out using the PubMed database. RESULTS: PRGF involves the use of patient's own biologically active proteins, growth factors, and biomaterial scaffolds for therapeutic purposes. This procedural technology is gaining interest in regenerative medicine due to its potential to stimulate and accelerate the tissue healing processes. The versatility and biocompatibility of this technology opens the door to a personalized medicine on ocular tissue regeneration. This review discusses the state of the art of the new treatments and technologies developed to promote ocular surface tissue regeneration. The standardized protocol that has been developed to source eye drops from PRGF technology is also described. The preclinical research, together with the most relevant clinical applications are summarized and discussed. CONCLUSIONS: The preliminary results suggest that the use of PRGF to enhance ocular tissue regeneration is safe and efficient.

Differential expression and localization of transient receptor potential vanilloid 1 in rabbit and human eyes.

INTRODUCTION: The superfamily of transient receptor potential (TRP) cation channels is involved in nociception. Members of this family, such as the vanilloid receptor type 1 (TRPV1) channel, are activated by a wide range of stimuli including heat (⟩43°C), low pH (⟨6.5), hypoxia, and hypertonicity. Here we report TRPV1 expression in rabbit and human eyes. MATERIAL AND METHODS: We analyzed the expression of TRPV1 mRNA by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and protein by immunohistochemistry in eyes of New Zealand White rabbits and humans. RESULTS: In rabbit and human eyes, TRPV1 protein was present in all layers of the corneal epithelium, but only in the basal layer of the conjunctiva. It was also in the ciliary and lens epithelia of both species as well as in the secretory cells of the rabbit lacrimal gland. The retinal pigment epithelium was positive for this protein in both species. TRPV1 was also present in rabbit Müller cells, where it had a similar pattern of expression to vimentin intermediate filaments. Analysis by qRT-PCR showed that TRPV1 mRNA was found in all of the structures where the protein was present. The highest level was in the lens and the lowest in the retina. CONCLUSION: TRPV1 is expressed in cells that are particularly active in Ca²âº exchange as well as in cells with significant water transport activity. Because TRPV1 is a Ca²âº channel, it probably functions in the regulation of both water and Ca²âº movements in ocular tissues.

Human adipose-derived stem cells for the treatment of chemically burned rat cornea: preliminary results.

PURPOSE: Adipose-derived stem cells (ADSC) are multipotent, safe, non-immunogenic and can differentiate into functional keratocytes in situ. The topical use of ADSC derived from human processed lipoaspirate was investigated for treating injured rat cornea. METHODS: A total of 19 rats were used. Six animals initially underwent corneal lesion experiments with 0.5 N NaOH (right eye) and 0.2 N (left). The 0.2 NaOH protocol was then used in 13 rats. All 26 eyes of 13 rats eyes received topical azythromycin bid for 3 d and divided into five treatment groups (n = 5 eyes/group), which included: control, stem cells, serum, stem + serum and adipose (raw human lipoaspirate). The four treatment groups received topical treatment three times daily for 3 d. Stem cells were isolated and harvested from human lipoaspirate. Topical eye drops were prepared daily with 1 × 10(5) cells/treatment. Fluorescein positive defect area and light microscope assessment was performed at 20, 28, 45, 50 and 74 h. Animals were sacrificed at 74 h for histological evaluation. Data were statistically analyzed for differences amongst groups. RESULTS: The stem cell-treated eyes had significantly smaller epithelial defects at each time point compared to control- and adipose-treated eyes (p < 0.05). This group showed slightly better epithelium healing than the serum and combined group, yet not significantly different. Histology showed that stem cell-treated corneas had complete re-epithelization, with less inflammatory cells and limited fibroblast activation structure compared with the control eyes. CONCLUSIONS: Our preliminary results show that topical treatment with ADSC seems to improve corneal wound healing.

Epidemiology of refractive errors in an adult European population: the Segovia study.

PURPOSE: To determine the prevalence of refractive errors in Segovia, Spain. METHODS: A cohort of 569 subjects was randomly selected in a stratified manner according to gender and age in a cross-sectional, population-based epidemiologic study, the target population of which was urban residents aged 40 to 79 years. All participants underwent an ophthalmic examination that included measurement of visual acuity (VA) and refraction, tonometry, anterior segment biomicroscopy, funduscopy, optic nerve head photography, and visual field testing. Of those, 417 subjects were enrolled who met the inclusion criteria of a phakic right eye and VA over 20/40. The prevalence of spherical errors was assessed after calculating the spherical equivalent and defining myopia as -0.5 diopters (D) or less and hyperopia as +0.50 D or more. The prevalence of astigmatism over 0.50 D was evaluated in minus cylinder form. RESULTS: The estimated prevalences (95% confidence interval) of myopia, hyperopia, and astigmatism, in the population were 25.4% (21.5-29.8%) 43.6% (39-48.4%), and 53.5% (48.7-58.2%), respectively. No significant gender difference was found in the prevalence of any refractive errors. The prevalence of myopia or the mean value did not change significantly with age. The mean hyperopia and the mean astigmatism (p < 0.01 for both) and the prevalence increased with increasing age (p < 0.01 for both). Anisometropia of 1 D or more was present in 12.3% (49/396 subjects). CONCLUSION: More than 60% of the Segovia population over 40 years of age has a refractive error, with 25.4% myopic and 43.6% hyperopic. Astigmatism is present in over half of the population and the types change with age.

Inflammatory response to contact lenses in patients with keratoconus compared with myopic subjects.

PURPOSE: To determine the levels of inflammatory molecules in the tears of patients who wore rigid gas permeable (RGP) contact lenses (CLs) and who had either keratoconus or myopia. METHODS: A prospective, case-control study with 4 groups enrolled 20 RGP CL keratoconus wearers and 28 keratoconus non-lens wearers, 20 myopic CL wearers, and 20 subjects with myopia that were non-lens wearers (1 eye per patient). Fifteen microliters of tears were collected by capillary flow. The concentration of cytokines (interleukin-6 [IL-6], IL-10, and tumor necrosis factor [TNF]-alpha), cell adhesion molecules (intercellular adhesion molecule 1 [ICAM-1] and vascular cell adhesion molecule 1 [VCAM-1]), and matrix metalloproteinase (MMP-9) was measured by enzyme-linked immunosorbent assay. RESULTS: The most significant differences associated with the wearing of RGP CLs in patients with keratoconus were seen in increased levels of proinflammatory cytokines (IL-6, 23.7 vs. 6.4 pg/mL, P = 0.001; TNF-alpha, 21.3 vs. 3.8 pg/mL, P = 0.028) and cell adhesion molecules (ICAM-1, 32.8 vs. 7.7 ng/mL, P < 0.0001; VCAM-1, 57.4 vs. 29.3 ng/mL, P < 0.0001). In patients with myopia, increased levels of TNF-alpha (4.2 vs. 1.8 pg/mL, P < 0.0001) and MMP-9 (12.9 vs. 6.1 ng/mL, P < 0.0001) were associated with the wearing of RGP CLs. CONCLUSIONS: Wearing RGP CLs induces overexpression of IL-6, TNF-alpha, ICAM-1, and VCAM-1 in the tears of patients with keratoconus. These increased levels are higher in cases with severe keratoconus.

Corneal lamellar dissection by using suture threads in porcine eyes.

PURPOSE: Lamellar dissection is one of the most delicate maneuvers in corneal surgery. We describe a new method that uses Ferrara ring instrumentation. METHODS: A 360 degrees tunnel is created at half of the stromal depth in porcine corneas. A suture (nylon 6-0 or Vicryl 6-0) was passed through the tunnel by using the Ferrara spatula. By means of alternate traction on the end of the suture thread, complete lamellar dissection was achieved. RESULTS: Light microscopy examination of the cornea confirmed that the dissection had a constant thickness and dissection depth. Scanning electron microscopy showed a homogeneous stromal surface without irregularities. CONCLUSIONS: This technique permits a homogeneous and safe lamellar dissection, which may prove useful in specific surgical procedures of the cornea.

Hyperopic LASIK retreatments with the Technolas laser.

PURPOSE: To evaluate the safety, efficacy, and predictability of hyperopic LASIK retreatments. METHODS: This retrospective, consecutive, non-comparative, observational study included 85 eyes that underwent hyperopic LASIK retreatment with 1-year follow-up. Complete ophthalmic examination included distance uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA), cycloplegic refraction, and pachymetry. Patients were divided into two groups according to the preoperative spherical equivalent refraction: group 1, < or = +3.9 diopters (D) and group 2, > or = +4.0 D. RESULTS: The UCVA improved from 0.31 +/- 0.2 to 0.7 +/- 0.2 in group 1 and from 0.2 +/- 0.2 to 0.6 +/- 0.2 in group 2 following retreatment. Mean spherical equivalent refraction improved from +2.8 +/- 0.85 to +0.2 +/- 0.9 in group 1 and from +5.3 +/- 0.9 to +0.3 +/- 1.3 in group 2 after retreatment. In group 1, 32 (72.7%) of 44 eyes had BSCVA > or = 20/25, and in group 2, 24 (58.5%) of 41 eyes had BSCVA > or = 20/25. After primary hyperopic LASIK, 25 (56.8%) of 44 eyes in group 1 and 19 (46.3%) of 41 eyes in group 2 maintained BSCVA or gained > or = 1 lines postoperatively in contrast to 21 (47.7%) of 44 eyes in group 1 and 22 (53.9%) of 41 eyes in group 2 after retreatment. In group 1, 11 (25%) of 44 eyes lost > or = 2 lines of BSCVA after initial hyperopic LASIK compared to 14 (31.8%) of 44 eyes after retreatment. In group 2, 10 (24.4%) of 41 eyes lost > or = 2 lines of BSCVA after initial hyperopic LASIK compared to 12 (29.2%) of 41 eyes after retreatment. After hyperopic LASIK retreatment, 31 (70.5%) of 44 eyes in group 1 and 19 (46.4%) of 41 eyes in group 2 were within +/- 0.5 D of emmetropia. Safety was 0.9 in both groups and efficacy was 0.8 and 0.7 in groups 1 and 2, respectively. Complications included epithelial ingrowth of 1 to 3 mm (30%) and flap edge melting (2%). CONCLUSIONS: Hyperopic LASIK retreatment improved the refractive results of initial hyperopic LASIK surgery with 20% to 30% of eyes gaining > or = 1 lines of BSCVA. The loss of BSCVA was greater after primary hyperopic LASIK than after retreatment.

Interface corneal edema secondary to steroid-induced elevation of intraocular pressure simulating diffuse lamellar keratitis.

PURPOSE: To describe interface corneal edema secondary to steroid-induced elevation of intraocular pressure (IOP) following LASIK. METHODS: Retrospective observational case series. Diffuse interface edema secondary to steroid-induced elevation of IOP was observed after LASIK simulating diffuse lamellar keratitis (DLK) in 13 eyes. Mean patient age was 31.4 +/- 5.3 years. Patients were divided into two groups according to provisional misdiagnosis: DLK group (group 1) comprised 11 eyes and infection group (group 2) comprised 2 eyes (microbial keratitis). Mean follow-up was 8.1 +/- 0.5 weeks. RESULTS: In the DLK group, typical diffuse haze was confined to the interface and extended to the visual axis, impairing vision in all eyes. Provisional diagnosis was late-onset DLK and topical steroids were started. Repeat examination showed elevated IOP as measured at the corneal center and periphery using applanation tonometry (mean 19.1 mmHg and 39.5 mmHg, respectively), causing interface edema with evident interface fluid pockets. Steroids were stopped and topical anti-glaucoma therapy was started. The interface edema decreased and at the end of follow-up the corneal transparency was restored and IOP dropped to normal values. The infection group demonstrated a microbial keratitis-like reaction and underwent flap lifting and interface wound debridement and biopsy with administration of fortified antibiotics and steroids. After elevated IOP was detected, steroids and antibiotics were stopped and topical anti-glaucoma therapy was started, resulting in the resolution of the interface edema. CONCLUSIONS: Interface fluid syndrome secondary to steroid-induced elevation of IOP might develop in steroid responders after LASIK with a misleading clinical picture simulating DLK or infectious keratitis. Management includes stopping topical steroids and starting topical antiglaucoma therapy.

Intracorneal hydrogel lenses and corneal aberrations.

PURPOSE: To investigate the optical performance of the cornea based on corneal aberrometry following intracorneal hydrogel lens implantation. METHODS: A retrospective, nonconsecutive, observational study of the anterior corneal surface aberration profile of four hyperopic eyes previously implanted with an intracorneal hydrogel lens were studied by videokeratographic elevation maps before and 6 months after surgery. RESULTS: Intracorneal hydrogel lenses reduced the optical performance in all four eyes by increasing the spherical aberrations by a mean factor of 1.87 and 1.95, coma aberrations by a mean factor of 2.98 and 3.01, and total higher order aberrations by a mean factor of 2.6 and 2.17 at 3.0-mm and 6.5-mm pupils, respectively (P<.005). CONCLUSIONS: Intracorneal hydrogel lenses decreased the optical performance of the cornea by significantly increasing spherical, coma, and total higher order aberrations.

Total and corneal optical aberrations induced by laser in situ keratomileusis for hyperopia.

PURPOSE: To evaluate changes induced by standard laser in situ keratomileusis (LASIK) for hyperopia on total and corneal optical quality. METHODS: Total and corneal aberrations were measured before and after standard hyperopic LASIK in 13 eyes (preoperative spherical equivalent refractive error +3.17 +/- 1.10 D). The Chiron Technolas 217C laser with PlanoScan was used. Total aberrations (measured using laser ray tracing) and corneal aberrations (estimated from a videokeratoscope) were described using Zernike terms. Root-mean-square wavefront error for both total and corneal aberrations, and through-focus Strehl ratio for the point spread function of the whole eye were used to assess optical changes induced by surgery. RESULTS: Third and higher order aberrations increased significantly after hyperopic LASIK (by a factor of 2.20 for total and 1.78 for corneal aberrations, for a 6.5-mm pupil). Spherical aberration changed to negative values (corneal average decreased by -0.85 +/- 0.48 microm and total average by -0.70 +/- 0.30 microm). Best Strehl ratio for the whole eye decreased by a factor of 1.84. Hyperopic LASIK induced larger changes than myopic LASIK, compared to an equivalent group of myopic eyes from a previous study. Induced corneal spherical aberration was six times larger after hyperopic LASIK, for a similar range of correction, and of opposite sign. As with myopic LASIK, changes in internal spherical aberration are of opposite sign to those induced on the corneal anterior surface. CONCLUSIONS: Hyperopic LASIK induced significant amounts of aberrations. The largest increase occurred in spherical aberration, which showed a shift (toward negative values) of opposite sign; increase was greater than for myopic LASIK.

Visual outcome in herpes simplex virus and varicella zoster virus uveitis: a clinical evaluation and comparison.

PURPOSE: To compare clinical characteristics and outcomes in patients with uveitis caused by herpes simplex virus (HSV) and varicella zoster virus (VZV). DESIGN: Retrospective comparative study. PARTICIPANTS: Forty patients with HSV uveitis and 24 patients with VZV uveitis. METHODS: A retrospective study of 40 patients with HSV and 24 patients with VZV uveitis was performed. The patients were followed between May 1987 and September 1999 (median follow-up time, 46 months). The diagnosis of HSV uveitis was made clinically and serologically, and the diagnosis of VZV uveitis was made clinically. MAIN OUTCOME MEASURES: Clinical presentation of the disease, ocular complications, visual acuity, surgical and medical treatments needed. RESULTS: Both populations were comparable for gender and age at disease onset. The course of the disease tended to be remitting and recurrent in HSV patients and chronic in VZV patients (P = 0.046). The most frequent ocular complication in both groups was secondary glaucoma (54% HSV, 38% VZV). Twenty-five percent of VZV patients developed posterior pole complications (cystoid macular edema, epiretinal membrane, papillitis, retinal fibrosis, and detachment) compared with 8% of HSV patients (P = 0.069). Treatment modalities selected were generally similar in the two groups, although periocular and systemic steroids were required more frequently in HSV patients (60% versus 25%; P = 0.01). Surgical procedures were required with similar frequency in both populations. The percentage of eyes that were legally blind at end of follow-up was also comparable (HSV, 20%; VZV, 21%). The visual outcome was similar in the studied populations. CONCLUSIONS: This study represents the only direct comparison of HSV and VZV uveitis patients reported in the literature. HSV patients were more likely to be treated with periocular and systemic steroids, and VZV patients were more likely to develop posterior pole complications (a finding of borderline significance). Other parameters evaluated in this study were not statistically different in the two patient groups.