Effects of Platelet Lysate Preparations on the Proliferation of HaCaT Cells

BACKGROUND: Standard protocols are lacking for the preparation of platelet lysates (PL) as an alternative to using fetal bovine serum as a cell culture supplement. This study aimed to establish optimum conditions for preparing PL for use in cell cultures. METHODS: Cell density in three pooled platelet concentrates (PC) were adjusted to 1x10(12)/L and 2x10(12)/L. PL was prepared from PC by 1 to 3 freeze-thaw (FT) cycles. HaCaT cells were cultured in media supplemented with 5% or 10% PL. Cell numbers were estimated using a Cell Counting Kit-8 (CCK-8; Dojindo Laboratories, Japan). Growth factors were quantified by using the Luminex 200 system (Luminex Corporation, USA). RESULTS: Cell proliferation rates in the presence of PLs were similar when prepared from PCs of both cell densities. The rates were higher in media containing 5% PL than 10% PL when prepared by two FT cycles. Concentrations of vascular endothelial growth factor (VEGF), platelet-derived growth factor-AB/BB (PDGF-AB/BB), PDGF-AA, and epidermal growth factor (EGF) were significantly higher in PL prepared from PC with a cell density of 2x10(12)/L than 1x10(12)/L PC. However, only VEGF and PDGF-AA concentrations in PLs were correlated with HaCaT cell counts. CONCLUSIONS: The 5% PL from PC with a cell density of 1x10(12)/L prepared by two FT cycles treatment was the most effective condition that supported steady HaCaT cell proliferation. Our finding may be useful for preparing PL-supplemented cell culture media.

Characterization of a Vancomycin-resistant Enterococcus faecium Outbreak Caused by 2 Genetically Different Clones at a Neonatal Intensive Care Unit

In July 2010, we identified an outbreak of vancomycin-resistant enterococci (VRE) in our 26-bed neonatal intensive care unit. We performed an epidemiological investigation after clinical cultures of 2 neonates were positive for VRE. Identification, susceptibility testing, and molecular characterization were performed. Cultures of 3 surveillance stool samples of inpatients and 5 environmental samples were positive for VRE. All isolates were identified as Enterococcus faecium containing the vanA gene. Two distinct clones were identified by performing pulsed-field gel electrophoresis. The 2 clones exhibited different pulsotypes, but they represented identical Tn1546 types. Two sequence types, ST18 and ST192, were identified among all of the isolates with multilocus sequence typing. Our investigation determined that the outbreak in the neonatal intensive care unit was caused by 2 genetically different clones. The outbreak may have occurred through clonal spread and horizontal transfer of the van gene.

HRCT Findings of Otosclerosis / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: With advances in techniques in the field of otology, we can now offer better treatment to patients with the conductive hearing loss. Otosclerosis is rare in the mongoloids so the diagnosis and treatment modality are not well established yet. In this study, we reviewed high resolution computerized tomography (HRCT) of patients with otsclerosis who were confirmed through explotympanotomy and found that there were specific radiological finding relevant to otsclerosis. The purpose of this study was to understand the HRCT findings of otosclerosis in order to provide more information about the disease. MATERIALS AND METHODS: We selected 42 HRCT available patients of 126 patients who were operated in the Seoul National university hospital from January 1981 to December 2000. We used GE HIGH SPEED ADVANTAGE (scan thickness 1 mm, scan interval 1 mm) CT scanner. RESULTS: There were radiolucent lesions in 48 ears(62%). The lesions were found in the fissula ante fenestram, cochlea, and the semicircular canal. CONCLUSIONS: HRCT could be used as an adjunctive diagnostic tool for the detection of otosclerotic lesion, stapedial or cochlear. We could find positive findings in 62% of the patients who showed progressive and conductive hearing loss.