Phosphoethanolamine Transferase LptA in Haemophilus ducreyi Modifies Lipid A and Contributes to Human Defensin Resistance In Vitro

Haemophilus ducreyi resists the cytotoxic effects of human antimicrobial peptides (APs), including α-defensins, β-defensins, and the cathelicidin LL-37. Resistance to LL-37, mediated by the sensitive to antimicrobial peptide (Sap) transporter, is required for H. ducreyi virulence in humans. Cationic APs are attracted to the negatively charged bacterial cell surface. In other gram-negative bacteria, modification of lipopolysaccharide or lipooligosaccharide (LOS) by the addition of positively charged moieties, such as phosphoethanolamine (PEA), confers AP resistance by means of electrostatic repulsion. H. ducreyi LOS has PEA modifications at two sites, and we identified three genes (lptA, ptdA, and ptdB) in H. ducreyi with homology to a family of bacterial PEA transferases. We generated non-polar, unmarked mutants with deletions in one, two, or all three putative PEA transferase genes. The triple mutant was significantly more susceptible to both α- and β-defensins; complementation of all three genes restored parental levels of AP resistance. Deletion of all three PEA transferase genes also resulted in a significant increase in the negativity of the mutant cell surface. Mass spectrometric analysis revealed that LptA was required for PEA modification of lipid A; PtdA and PtdB did not affect PEA modification of LOS. In human inoculation experiments, the triple mutant was as virulent as its parent strain. While this is the first identified mechanism of resistance to α-defensins in H. ducreyi, our in vivo data suggest that resistance to cathelicidin LL-37 may be more important than defensin resistance to H. ducreyi pathogenesis

A Mechanism for Chronic Filarial Hydrocele with Implications for Its Surgical Repair

Chronic hydrocele is the accumulation of fluid around the testis leading to an increase in the volume of the scrotal contents. Depending on the volume of fluid, hydrocele can be disfiguring and even incapacitating. Chronic hydrocele has multiple etiologies, but irrespective of the cause, surgery is the standard form of treatment and this can be done using different surgical techniques. The prevalence of chronic hydrocele in bancroftian filariasis endemic areas—a parasitic disease transmitted by mosquito—is very high and represents the most common clinical manifestation of bancroftosis, following by swollen legs of lower limbs or lymphedema among women. In Greater Recife, northeastern, Brazil, a bancroftian filariasis endemic area, a pioneering, prospective surgical study proposes a new mechanism for filarial-induced hydrocele and presents evidence that the filarial hydrocele fluid may damage the testis. Thus, based on the findings presented, the authors propose that in bancroftian filariasis endemic areas hydrocele patients should be operated on using a specific surgical technique in order to avoid recurrence of the disease, and consequently, additional damage to the testicle

EM-21 Retrieval Knowledge Center: Waste Retrieval Challenges

EM-21 is the Waste Processing Division of the Office of Engineering and Technology, within the U.S. Department of Energy’s (DOE) Office of Environmental Management (EM). In August of 2008, EM-21 began an initiative to develop a Retrieval Knowledge Center (RKC) to provide the DOE, high level waste retrieval operators, and technology developers with centralized and focused location to share knowledge and expertise that will be used to address retrieval challenges across the DOE complex. The RKC is also designed to facilitate information sharing across the DOE Waste Site Complex through workshops, and a searchable database of waste retrieval technology information. The database may be used to research effective technology approaches for specific retrieval tasks and to take advantage of the lessons learned from previous operations. It is also expected to be effective for remaining current with state-of-the-art of retrieval technologies and ongoing development within the DOE Complex. To encourage collaboration of DOE sites with waste retrieval issues, the RKC team is co-led by the Savannah River National Laboratory (SRNL) and the Pacific Northwest National Laboratory (PNNL). Two RKC workshops were held in the Fall of 2008. The purpose of these workshops was to define top level waste retrieval functional areas, exchange lessons learned, and develop a path forward to support a strategic business plan focused on technology needs for retrieval. The primary participants involved in these workshops included retrieval personnel and laboratory staff that are associated with Hanford and Savannah River Sites since the majority of remaining DOE waste tanks are located at these sites. This report summarizes and documents the results of the initial RKC workshops. Technology challenges identified from these workshops and presented here are expected to be a key component to defining future RKC-directed tasks designed to facilitate tank waste retrieval solutions

EFS shows biallelic methylation in uveal melanoma with poor prognosis as well as tissue-specific methylation

<p>Abstract</p> <p>Background</p> <p>Uveal melanoma (UM) is a rare eye tumor. There are two classes of UM, which can be discriminated by the chromosome 3 status or global mRNA expression profile. Metastatic progression is predominantly originated from class II tumors or from tumors showing loss of an entire chromosome 3 (monosomy 3). We performed detailed <it>EFS </it>(<it>embryonal Fyn-associated substrate</it>) methylation analyses in UM, cultured uveal melanocytes and normal tissues, to explore the role of the differentially methylated <it>EFS </it>promoter region CpG island in tumor classification and metastatic progression.</p> <p>Methods</p> <p><it>EFS </it>methylation was determined by direct sequencing of PCR products from bisulfite-treated DNA or by sequence analysis of individual cloned PCR products. The results were associated with clinical features of tumors and tumor-related death of patients.</p> <p>Results</p> <p>Analysis of 16 UM showed full methylation of the <it>EFS </it>CpG island in 8 (50%), no methylation in 5 (31%) and partial methylation in 3 (19%) tumors. Kaplan-Meier analysis revealed a higher risk of metastatic progression for tumors with <it>EFS </it>methylation (p = 0.02). This correlation was confirmed in an independent set of 24 randomly chosen tumors. Notably, only UM with <it>EFS </it>methylation gave rise to metastases. Real-time quantitative RT-PCR expression analysis revealed a significant inverse correlation of <it>EFS </it>mRNA expression with <it>EFS </it>methylation in UM. We further found that <it>EFS </it>methylation is tissue-specific with full methylation in peripheral blood cells, and no methylation in sperm, cultured primary fibroblasts and fetal muscle, kidney and brain. Adult brain samples, cultured melanocytes from the uveal tract, fetal liver and 3 of 4 buccal swab samples showed partial methylation. <it>EFS </it>methylation always affects both alleles in normal and tumor samples.</p> <p>Conclusions</p> <p>Biallelic <it>EFS </it>methylation is likely to be the result of a site-directed methylation mechanism. Based on partial methylation as observed in cultured melanocytes we hypothesize that there might be methylated and unmethylated precursor cells located in the uveal tract. The <it>EFS </it>methylation of a UM may depend on which type of precursor cell the tumor originated from.</p

Survival after Robotic-assisted Prostatectomy for Localized Prostate Cancer: An Epidemiologic Study

Backgrounds:To determine the potential survival benefit associated with robotic-assisted laparoscopic prostatectomy (RALP) compared to open radical prostatectomy (ORP) for prostate cancer.Summary of Background Data:RALP has become the dominant surgical approach for localized disease in the absence of randomized clinical evidence and despite of the factor that RALP is more expensive than ORP.Methods:We performed a cohort study involving patients who underwent RALP and ORP for localized prostate cancer at the Commission on Cancer- accredited hospitals in the United States. Overall survival was analyzed using the Kaplan-Meier method, log-rank test, Cox proportional hazards models, and propensity score-matched analyses. An interrupted time-series analysis using the surveillance, epidemiology, and end results program database was also performed.Results:From 2010 to 2011, 37,645 patients received RALP and 12,655 patients received ORP. At a median follow-up of 60.7 months, RALP was associated with improved overall survival by both univariate [hazard ratio (HR), 0.69; P \u3c 0.001] and multivariate analysis (HR, 0.76; P \u3c 0.001) compared with ORP. Propensity score-matched analysis demonstrated improved 5-year all-cause mortality (3.9% vs 5.5%, HR, 0.73; P \u3c 0.001) for RALP. The interrupted time-series analysis demonstrated the adoption of robotic surgery coincided with a systematic improvement in the 5-year cancer-specific survival rate of 0.17% (95% confidence interval, 0.06-0.25) per year after 2003 (P = 0.004 for change of trend), as compared to the time before adoption of RALP (1998-2003, annual percentage change, 0.01%; 95% confidence interval, -0.06 to 0.08). Sensitivity analysis suggested that the results from the interrupted time-series analysis were consistent with the improvement in the all-cause mortality demonstrated in the survival analysis (P = 0.87).Conclusions:In this epidemiologic analysis, RALP was associated with a small but statistically significant improvement in 5-year all-cause mortality compared to ORP for localized prostate cancer. This is the first time in the literature to report a survival benefit with RALP. Our findings have significant quality and cost implications, and provide assurance regarding a dominant adoption of more expensive technology in the absence of randomized controlled trials

LptA contributes to modification of lipid A with PEA.

<p>Negative-ion MALDI-MS spectra of <i>O</i>-LOS from (A) 35000HP<i>ΔptdB</i>, (B) 35000HP<i>ΔptdA</i>, (C) 35000HP<i>ΔlptA</i>, and (D) 35000HP. The Fig shows zoomed images from representative spectra for each strain. The <i>O</i>-deacylated monophosphorylated lipid A (MPLA) was observed at <i>m/z</i> 951.46 or 951.45, this structure plus the addition of PEA was observed at <i>m/z</i> 1074.46 or 1074.47. The MPLA plus PEA was not observed in the 35000HP<i>ΔlptA</i> samples.</p

35000HPΔPEAT is fully virulent in vivo.

<p>^a Volunteers 441 and 442 were inoculated in the first iteration. Volunteers 444, 445, and 446 were inoculated in the second iteration. Volunteer 447 was inoculated in the third iteration. Volunteers 451 and 453 were inoculated in the fourth iteration.</p><p>^b M, Male; F, Female</p><p>^c P, 35000HP (parent); M, 35000HPΔPEAT (mutant)</p><p>^d Mutant-inoculated sites received estimated delivered doses of 56, 112, or 224 CFU.</p><p>^e Mutant-inoculated sites received estimated delivered doses of 40, 80, or 159 CFU.</p><p>35000HPΔPEAT is fully virulent in vivo.</p

Bacterial strains and plasmids used in study.

<p>^a StrepR, resistance to streptomycin; Cm^R, resistance to chloramphenicol; AmpR, resistance to ampicillin; KanR, resistance to kanamycin; SpecR, resistance to spectinomycin.</p><p>Bacterial strains and plasmids used in study.</p