Antibacterial and anti-biofilm activity, and mechanism of action of pleurocidin against drug resistant Staphylococcus aureus.

The abuse of antibiotics has resulted in the emergence of multi-drug-resistant bacteria. Staphylococcus aureus is a frequent cause of infections, and antibiotic-resistant S. aureus has become a serious problem. Antimicrobial peptides play an important role in innate immunity and are attracting increasing attention as alternative antibiotics. In a previous study, pleurocidin, derived from winter flounder, was identified as a 25-amino acid antimicrobial peptide with no cytotoxicity toward mammalian cells and low hemolytic activity. In the present study, pleurocidin was observed to exhibit antimicrobial activity against gram-positive and gram-negative bacteria, especially against drug resistant S. aureus. Pleurocidin retained its antibacterial activity against drug resistant S. aureus in the presence of a physiological salt concentration. Membrane depolarization assays and propidium iodide uptake indicated that pleurocidin kills bacteria by damaging the integrity of the bacterial membrane. DNA binding assays revealed that pleurocidin binds to DNA. Thus, pleurocidin targets not only the bacterial membrane, but also their DNA. S. aureus biofilms have become a serious problem because of increased resistance to antibiotics. Therefore, we investigated the effect of pleurocidin on biofilm inhibition and eradication using crystal violet staining and microscopic observation. Pleurocidin inhibited and eradicated biofilms at low concentrations. Taken together, the results suggested that pleurocidin is a promising candidate therapeutic agent to treat drug-resistant bacteria and biofilm-related infections.

Comparison of epitheliotrophic factors in autologous serum eyedrops from sera of chronic renal failure patients vs. normal controls.

PURPOSE: To investigate the composition and biological activity of serum epitheliotrophic factors from chronic renal failure (CRF) patients vs. healthy controls. METHODS: Twenty, 50 and 100 % autologous serum eyedrops (ASEs) were prepared from 16 CRF patients and 16 normal subjects. Serum epithelial growth factor (EGF), platelet-derived growth factor-AB (PDGF-AB), transforming growth factor-ß1 (TGF-ß1) and fibronectin levels were quantified using enzyme-linked immunosorbent assay kits. A 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazoliumbromide (MTT) assay was used to compare the proliferative effects of serum from CRF patients and healthy donors in a human corneal epithelial cell (HCEC) culture model. Migration assays were conducted via manual scraping of HCECs for migratory potential of ASEs. Morphologic changes were studied with transmission electron microscopy (TEM). RESULTS: EGF, PDGF-AB and TGF-ß1 levels in ASEs from healthy donors were significantly higher than in serum of CRF patients. Cellular proliferation was similar in the CRF patient and normal control groups. ASEs from the normal group had a significantly higher effect on cell migration. ASEs in both groups facilitated better proliferation and migration than the negative control. Furthermore, we observed an enhancement after incubation with diluted serum vs. undiluted serum. In TEM analysis, HCECs incubated with CRF patients' 50 % ASEs showed some loss of microvilli without alterations of cytoplasmic organelles. CONCLUSIONS: Epitheliotrophic factors concentrations and biologic activities from CRF patient sera differed from healthy controls. ASEs in CRF patients are also helpful in the corneal healing process, especially when applied at a 50 % concentration.

Clinical features and glaucoma according to optic disc size in a South Korean population: the Namil study.

PURPOSE: To assess the proportion of glaucomatous eyes based on the association between optic disc (OD) size and its clinical determinants in the resident population of Namil-myon, Central South Korea. METHODS: Of the 1,532 participants in the Namil study, we included 1,410 Koreans (2,734 eyes) with legible fundus photographs in this study. Following the estimation of OD size on the photographs using Image J software, we corrected for image magnification. Associations between the clinical features, such as age, sex, axial length (AL), spherical equivalent (SE), and central corneal thickness, and the estimated OD size were assessed for individual eyes. After adjusting for the influencing factors, the proportion of glaucoma was compared among three categories of measured OD size (small, medium, and large OD groups). RESULTS: After adjusting for the potential confounders using a linear mixed model, age, sex, AL, and SE were correlated with the OD size estimates (P = 0.003, P = 0.029, P < 0.001, and P < 0.001, respectively). The percentage of glaucomatous eyes was 3.77 % in the small disc group, which was higher than in the other groups (P = 0.054). In particular, normal tension glaucoma (NTG) was statistically significantly more frequent in this group (odds ratio = 1.86, P = 0.042). CONCLUSIONS: These results suggest that clinical features such as age, sex, AL, and SE might need to be considered for an accurate evaluation of the OD. In addition, in individuals with a small OD, the presence of NTG must be carefully investigated in the South Korea population.

Horner's syndrome with abducens nerve palsy.

A 68-year-old male patient presented with a week of sudden diplopia. He had been diagnosed with nasopharyngeal cancer 8 months prior and had undergone chemotherapy with radiotherapy. Eight-prism diopter right esotropia in the primary position and a remarkable limitation in abduction in his right eye were observed. Other pupillary disorders and lid drooping were not found. After three weeks, the marginal reflex distance 1 was 3 mm in the right eye and 5 mm in the left eye. The pupil diameter was 2.5 mm in the right eye, and 3 mm in the left eye under room illumination. Under darkened conditions, the pupil diameter was 3.5 mm in the right eye, and 5 mm in the left eye. After topical application of 0.5% apraclonidine, improvement in the right ptosis and reversal pupillary dilatation were observed. On brain magnetic resonance imaging, enhanced lesions on the right cavernous sinus, both sphenoidal sinuses, and skull base suggested the invasion of nasopharyngeal cancer. Lesions on the cavernous sinus need to be considered in cases of abducens nerve palsy and ipsilateral Horner's syndrome.