Molecular Characterization of Vancomycin-Resistant Enterococci from Hospitalized Patients and Poultry Products in The Netherlands

Vancomycin-resistant enterococci (VRE) pose an emerging health risk, but little is known about the precise epidemiology of the genes coding for vancomycin resistance. To determine whether the bacterial flora of consumer poultry serves as a gene reservoir, the level of contamination of poultry products with VRE was determined. VRE were genotyped by pulsed-field gel electrophoresis (PFGE), and transposon structure mapping was done by PCR. The vanX-vanY intergenic regions of several strains were further analyzed by sequencing. A total of 242 of 305 (79%) poultry products were found to be contaminated with VRE. Of these VRE, 142 (59%) were high-level-vancomycin-resistant Enterococcus faecium strains (VREF). PFGE revealed extensive VREF heterogeneity. Two genotypes were found nationwide on multiple occasions: type A (22 of 142 VREF [15%]) and type B (14 of 142 VREF [10%]). No PFGE-deduced genetic overlap was found when VREF from humans were compared with VREF from poultry. Two vanA transposon types were identified among poultry strains. In 59 of 142 (42%) of the poultry VREF, the size of the intergenic region between vanX and vanY was ~1,300 bp. This transposon type was not found in human VREF. In contrast, all human strains and 83 of 142 (58%) of the poultry VREF contained an intergenic region 543 bp in size. Sequencing of this 543-bp intergenic vanX-vanY region demonstrated full sequence conservation. Though preliminary, these data suggest that dissemination of the resistance genes carried on transposable elements may be of greater importance than clonal dissemination of resistant strains. This observation is important for developing strategies to control the spread of glycopeptide resistance.     

Immunogenic properties of octasaccharide-protein conjugates derived from Klebsiella serotype 11 capsular polysaccharide.

The tetrasaccharide repeating unit of the capsular polysaccharide of Klebsiella serotype 11, K11PS, comprises the following sequence: [----3)-beta-D-GlcpA-(1----3)-alpha-D-Galp-(1----3)-beta-D-Glcp-(1 ----] with a 4,6-O-(1-carboxyethylidene)-alpha-D-galactopyranosyl residue linked to O-4 of the glucuronic acid residue. Octasaccharide (OS) derived from K11PS by bacteriophage phi 11-associated glycanase, was coupled to bovine serum albumin and to keyhole limpet hemocyanin. The immunogenicity of various antigens after intraperitoneal immunization was studied by measuring the levels of circulating antibodies. Injection of BALB/c mice with K11PS resulted in induction of 2-mercaptoethanol-sensitive immunoglobulin M antibodies. The responses observed in BALB/c nu/nu mice and in male (CBA/N X C3H/HeN)F1 mice indicate that K11PS is a thymus-independent type 2 antigen. Immunization of BALB/c mice with either OS-bovine serum albumin or OS-keyhole limpet hemocyanin resulted in the induction of circulating 2-mercaptoethanol-resistant immunoglobulin G antibodies. Results in BALB/c nu/nu mice indicate that the OS-protein conjugates are thymus-dependent antigens. Since the OS-keyhole limpet hemocyanin conjugate induced antibodies in both (CBA/N X C3H/HeN)F1 females and males, we propose to refer to this kind of antigen as a thymus-dependent type 1 antigen, whereas OS-bovine serum albumin, which evoked immunoglobulins in (CBA/N X C3H/HeN)F1 females only, can be referred to as a thymus-dependent type 2 antigen.     

Imaging the myocardial ischemic cascade

Non-invasive imaging plays a growing role in the diagnosis and management of ischemic heart disease from its earliest manifestations of endothelial dysfunction to myocardial infarction along the myocardial ischemic cascade. Experts representing the North American Society for Cardiovascular Imaging and the European Society of Cardiac Radiology have worked together to organize the role of non-invasive imaging along the framework of the ischemic cascade. The current status of non-invasive imaging for ischemic heart disease is reviewed along with the role of imaging for guiding surgical planning. The issue of cost effectiveness is also considered. Preclinical disease is primarily assessed through the coronary artery calcium score and used for risk assessment. Once the patient becomes symptomatic, other imaging tests including echocardiography, CCTA, SPECT, PET and CMR may be useful. CCTA appears to be a cost-effective gatekeeper. Post infarction CMR and PET are the preferred modalities. Imaging is increasingly used for surgical planning of patients who may require coronary artery bypass.     

Assessing Lung Cancer Screening Programs under Uncertainty in a Heterogeneous Population

Background

Lung cancer screening can reduce cancer mortality. Most implementation studies focus only on low-dose computed tomography (LDCT) and clinical attributes of screening and do not include preferences of potential participants. In this study we evaluated the perceived value of screening programs based on LDCT, breath analysis (BA), or blood biomarkers (BB) according to the perspective of the target population.

Oxygenated metabolites of anandamide and 2-arachidonoylglycerol: conformational analysis and interaction with cannabinoid receptors,membrane transporter,and fatty acid amide hydrolase

This study was aimed at finding structural requirements for the interaction of the acyl chain of endocannabinoids with cannabinoid receptors, membrane transporter protein, and fatty acid amide hydrolase (FAAH). To this end, the flexibility of the acyl chain was restricted by introduction of an 1-hydroxy-2Z,4E-pentadiene system in anandamide (N-arachidonoylethanolamine, AEA) and 2-arachidonoylglycerol (2-AG) at various positions using different lipoxygenases. This brought about selectivity and attenuated the binding potency of AEA and 2-AG. Although the displacement constants were modest, 15(S)-hydroxy-eicosa-5Z,8Z,11Z,13E-tetraenoyl-N-(2-hydroxyethyl)amine was found to bind selectively to the CB(1) receptor, whereas its 1-arachidonoyl-sn-glycerol analogue and 13(S)-hydroxy-octadeca-9Z,11E-dienoyl-N-(2-hydroxyethyl)amine could selectively bind to the CB(2) receptor. 11(S)-Hydroxy-eicosa-5Z,8Z,12E,14Z-tetraenoyl-N-(2-hydroxyethyl)amine did not bind to either receptor, whereas 12(S)-hydroxy-eicosa-5Z,8Z,10E,14Z-tetraenoyl-N-(2-hydroxyethyl)amine did bind to both CB receptors with an affinity similar to that of AEA. All oxygenated anandamide derivatives were good inhibitors of FAAH (low micromolar K(i)) but were ineffective on the AEA transporter. 2-AG rapidly isomerizes into 1(3)-arachidonoyl-sn-glycerol. Both 1- and 3-arachidonoyl-sn-glycerol did not bind to either CB receptor and did not interfere with AEA transport. Thus, after it is isomerized, 2-AG is inactivated, thereby decreasing effective concentrations of 2-AG. Analysis of (1)H NMR spectra revealed that chloroform did not induce notably different conformations in the acyl chain of 15(S)-hydroxy-eicosa-5Z,8Z,11Z,13E-tetraenoic acid as compared with water. Molecular dynamics (MD) simulations of AEA and its analogues in the presence of explicit water molecules revealed that a tightly folded conformation of the acyl chain is not the only requirement for CB(1) binding. Structural details of the C(2)-C(15) loop, such as an sp(2) carbon at position 11, are necessary for receptor binding. The MD simulations may suggest that the average orientations of the pentyl tail of AEA and 12(S)-hydroxy-eicosa-5Z,8Z,10E,14Z-tetraenoyl-N-(2-hydroxyethyl)amine are different from that of the low-affinity, inactive ligands.     

Estimating Non-Response Bias in Family Studies: Application to Mental Health and Lifestyle

Non-response to mailed surveys reduces the effective sample size and may introduce bias. Non-response has been studied by (1) comparison to available data in population based registers, (2) directly contacting non-respondents by telephone or single-item reply cards, and (3) longitudinal repetition of the survey. The goal of this paper was to propose an additional method to study non-response bias: when the variable of interest has a familial component, data from respondents can be used as proxy for the data from their non-responding family members. This approach was used with data on smoking, alcohol consumption, physical activity, coffee- and tea-use, education, body mass index, religion, burnout, life events, personality and mental health in large number of siblings and DZ twins registered with the Netherlands Twin Register. In addition, for smoking behavior, we also used the second strategy by sending a reply card. Results show that scores of members from less cooperative families or incomplete twin pairs tended to be more unfavorable than the scores from highly cooperative families or complete twin pairs. For example, family members from less cooperative families cycled less often and scored higher on anxious depression and neuroticism. For smoking, both the results of the reply card and the results of the additional method suggested a higher percentage smokers among the non-respondents but this was only significant with reply card method. In general, differences between highly/less cooperative families and complete/incomplete DZ twins were small. Results suggest that, even for studies with moderate response rates, data collected on health, personality and lifestyle are relatively unbiased.