Acinetobacter baumannii invades epithelial cells and outer membrane protein A mediates interactions with epithelial cells

<p>Abstract</p> <p>Background</p> <p><it>Acinetobacter baumannii </it>is a nosocomial pathogen of increasing importance, but the pathogenic mechanism of this microorganism has not been fully explored. This study investigated the potential of <it>A. baumannii </it>to invade epithelial cells and determined the role of <it>A. baumannii </it>outer membrane protein A (AbOmpA) in interactions with epithelial cells.</p> <p>Results</p> <p><it>A. baumannii </it>invaded epithelial cells by a zipper-like mechanism, which is associated with microfilament- and microtubule-dependent uptake mechanisms. Internalized bacteria were located in the membrane-bound vacuoles. Pretreatment of recombinant AbOmpA significantly inhibited the adherence to and invasion of <it>A. baumannii </it>in epithelial cells. Cell invasion of isogenic AbOmpA^-mutant significantly decreased as compared with wild-type bacteria. In a murine pneumonia model, wild-type bacteria exhibited a severe lung pathology and induced a high bacterial burden in blood, whereas AbOmpA^-mutant was rarely detected in blood.</p> <p>Conclusion</p> <p><it>A. baumannii </it>adheres to and invades epithelial cells. AbOmpA plays a major role in the interactions with epithelial cells. These findings contribute to the understanding of <it>A. baumannii </it>pathogenesis in the early stage of bacterial infection.</p

The effects of pre-pregnancy body mass index and gestational weight gain on perinatal outcomes in Korean women: a retrospective cohort study

<p>Abstract</p> <p>Background</p> <p>The purpose of the study was to evaluate the effects of maternal pre-pregnancy body mass index (BMI) and gestational weight gain on perinatal outcomes in a population of Korean women.</p> <p>Methods</p> <p>We retrospectively reviewed the medical records of 2,454 women who had received antenatal care at Seoul St. Mary's Hospital from January 2007 to December 2009. We used World Health Organization definitions for Asian populations of underweight (BMI < 18.5), normal (BMI equal or higher 18.5 and < 23), overweight (BMI equal or higher 23 and < 25), and obese (BMI equal or higher 25). We analyzed perinatal outcomes according to the pre-pregnancy BMI and weight gain during pregnancy, and calculated the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) from multiple logistic regression models by considering maternal age, parity, number of fetuses, length of gestation, and medical history.</p> <p>Results</p> <p>Among obese women, the adjusted ORs for gestational diabetes, hypertensive disorder, and incompetent internal os of cervix were 4.46, 2.53, and 3.70 (95% CI = 2.63-7.59, 1.26-5.07, and 1.50-9.12), respectively, and the adjusted ORs for neonatal complications such as macrosomia and low Apgar score were 2.08 and 1.98 (95% CI = 1.34-3.22 and 1.19-3.29), respectively, compared with normal weight women. However, there was no positive linear association between gestational weight gain and obstetric outcomes. In normal weight women, maternal and neonatal complications were significantly increased with inadequate weight gain during pregnancy (p < 0.0001 and = 0.0180, respectively), and we observed similar results in underweight women (p = 0.0136 and 0.0004, respectively).</p> <p>Conclusions</p> <p>This study shows that pre-pregnancy overweight and obesity are more closely related to the adverse obstetric outcomes than excess weight gain during pregnancy. In addition, inadequate weight gain during pregnancy can result in significant complications.</p

Optical Spectroscopy of Supernova Remnants in M81 and M82

We present spectroscopy of 28 SNR candidates as well as one H II region in M81, and two SNR candidates in M82. Twenty six out of the M81 candidates turn out to be genuine SNRs, and two in M82 may be shocked condensations in the galactic outflow or SNRs. The distribution of [N II]/H{\alpha} ratios of M81 SNRs is bimodal. M81 SNRs are divided into two groups in the spectral line ratio diagrams: an [O III]-strong group and an [O III]-weak group. The latter have larger sizes, and may have faster shock velocity. [N II]/H{\alpha} ratios of the SNRs show a strong correlation with [S II]/H{\alpha} ratios. They show a clear radial gradient in [N II]/H{\alpha} and [S II]/H{\alpha} ratios: dLog ([N II]/H{\alpha})/dLog R = -0.018 {\pm} 0.008 dex/kpc and dLog ([S II]/H{\alpha})/dLog R = -0.016 {\pm} 0.008 dex/kpc where R is a deprojected galactocentric distance. We estimate the nitrogen and oxygen abundance of the SNRs from the comparison with shock-ionization models. We obtain a value for the nitrogen radial gradient, dLog(N/H)/dLogR = -0.023 {\pm} 0.009 dex/kpc, and little evidence for the gradient in oxygen. This nitrogen abundance shows a few times flatter gradient than those of the planetary nebulae and H II regions. We find that five SNRs are matched with X-ray sources. Their X-ray hardness colors are consistent with thermal SNRs.Comment: 19 pages, 24 figures, 5 tables, ApJ accepte

Axial strain dependence of all-fiber acousto-optic tunable filters

We report the axial strain dependence of two types of all-fiber acousto-optic tunable filters based on flexural and torsional acoustic waves. Experimental observation of the resonant wavelength shift under applied axial strain could be explained by theoretical consideration of the combination of acoustic and optical effects. We discuss the possibility of suppressing the strain effect in the filters, or conversely, the possibility of using the strain dependence for wavelength tuning or strain sensors

Discovery of Novel Sources of Vitamin B12 in Traditional Korean Foods from Nutritional Surveys of Centenarians

Human longevity can be explained by a variety of factors, among them, nutritional factor would play an important role. In our study of Korean centenarians for their longevity, the apparent nutritional imbalance in the traditional semi-vegetarian diet raised a special attention, especially on vitamin B12 status, supplied by animal foods. Interestingly, we found that the prevalence of vitamin B12 deficient Korean centenarians was not higher compared with those from Western nations with animal-oriented traditional foods. We assumed that there might be some unveiled sources for vitamin B12 in the Korean traditional foods. Screening of vitamin B12 contents has revealed that some traditional soybean-fermented foods, such as Doenjang and Chunggukjang, and seaweeds contain considerable amounts of vitamin B12. Taken together, it can be summarized that the traditional foods, especially of fermentation, might be evaluated for compensation of the nutritional imbalance in the vegetable-oriented dietary pattern by supplying vitamin B12, resulting in maintenance of health status

GaAs droplet quantum dots with nanometer-thin capping layer for plasmonic applications

We report on the growth and optical characterisation of droplet GaAs quantum dots with extremely-thin (11 nm) capping layers. To achieve such result, an internal thermal heating step is introduced during the growth and its role in the morphological properties of the quantum dots obtained is investigated via scanning electron and atomic force microscopy. Photoluminescence measurements at cryogenic temperatures show optically stable, sharp and bright emission from single quantum dots, at near-infrared wavelengths. Given the quality of their optical properties and the proximity to the surface, such emitters are ideal candidates for the investigation of near field effects, like the coupling to plasmonic modes, in order to strongly control the directionality of the emission and/or the spontaneous emission rate, crucial parameters for quantum photonic applications.Comment: 1 pages, 3 figure

Effects of fibrin-binding oligopeptide on osteopromotion in rabbit calvarial defects

Purpose: Fibronectin (FN) has been shown to stimulate bone regeneration in animal models. The aim of this study was to evaluate the capacity of bovine bone mineral coated with synthetic oligopeptides to enhance bone regeneration in rabbit calvarial defects. Methods: Oligopeptides including fibrin-binding sequences of FN repeats were synthesized on the basis of primary and tertiary human plasma FN structures. Peptide coated and uncoated bone minerals were implanted into 10 mm calvarial defects in New Zealand white rabbits, and the animals were sacrificed at 4 or 8 weeks after surgery. After specimens were prepared, histologic examination and histomorphometric analysis were performed. Results: At 4 weeks after surgery, the uncoated groups showed a limited amount of osteoid formation at the periphery of the defect and the oligopeptide coated groups showed more osteoid formation and new bone formation in the center of the defect as well as at the periphery. At 8 weeks, both sites showed increased new bone formation. However, the difference between the two sites had reduced. Conclusions: Fibrin-binding synthetic oligopeptide derived from FN on deproteinized bovine bone enhanced new bone formation in rabbit calvarial defects at the early healing stage. This result suggests that these oligopeptides can be beneficial in reconstructing oral and maxillofacial deformities or in regenerating osseous bone defects. ⓒ 2010 Korean Academy of Periodontology.