How Survey Design Affects Inference Regarding Health Perceptions and Outcomes

This paper considers the role of survey design and question phrasing in evaluating the subjective health assessment responses using the Survey of Health, Ageing and Retirement in Europe (SHARE) dataset. A unique feature of this dataset is that respondents were twice asked during the survey to evaluate their health on a five-point scale, using two different sets of descriptors to define the five points, with the ordering of which set was first given determined randomly. We find no evidence to refute the assertion that the order was determined by random assignment. Yet we document differences in the response distributions between the two questions, as well as differences in inference in comparing the two populations (those that were asked one question first versus those that were asked the other). We then consider determinants of the degree of concordance between the two questions, as well as the determinants of individuals that provide conflicting responses. There appears to be evidence to suggest that individuals’ assessments of their health in response to the second question may be influenced by the battery of health questions that were asked following the first assessment. We find that information in self-assessed health responses is useful in examining health outcomes. Our results suggest that adjusting such responses to take into account framing and sequencing of questions may improve inference. In addition, we show that accounting for survey design may be important in models for predicting outcomes of interest, such as the probability of a major health event.

A versatile method to separate complex lipid mixtures using 1-butanol as eluent in a reverse-phase UHPLC-ESI-MS system

Simple, robust and versatile LC-MS based methods add to the rapid assessment of the lipidome of biological cells. Here we present a versatile RP-UHPLC-MS method using 1-butanol as the eluent, specifically designed to separate different highly hydrophobic lipids. This method is capable of separating different lipid classes of glycerophospholipid standards, in addition to phospholipids of the same class with a different acyl chain composition. The versatility of this method was demonstrated through analysis of lipid extracts of the bacterium Escherichia coli and the archaeon Sulfolobus acidocaldarius. In contrast to 2-propanol-based methods, the 1-butanol-based mobile phase is capable of eluting highly hydrophobic analytes such as cardiolipins, tetraether lipids and mycolic acids during the gradient instead of the isocratic purge phase, resulting in an enhanced separation of cardiolipins and extending the analytical range for RPLC

A promiscuous archaeal cardiolipin synthase enables construction of diverse natural and unnatural phospholipids

Cardiolipins (CL) are a class of lipids involved in the structural organization of membranes, enzyme functioning, and osmoregulation. Biosynthesis of CLs has been studied in eukaryotes and bacteria, but has been barely explored in archaea. Unlike the common fatty acyl chain-based ester phospholipids, archaeal membranes are made up of the structurally different isoprenoid-based ether phospholipids, possibly involving a different cardiolipin biosynthesis mechanism. Here, we identified a phospholipase D motif-containing cardiolipin synthase (MhCls) from the methanogen Methanospirillum hungatei. The enzyme was overexpressed in Escherichia coli, purified, and its activity was characterized by LC-MS analysis of substrates/products. MhCls utilizes two archaetidylglycerol (AG) molecules in a transesterification reaction to synthesize glycerol-di-archaetidyl-cardiolipin (Gro-DACL) and glycerol. The enzyme is non-selective to the stereochemistry of the glycerol-backbone and the nature of the lipid tail, as it also accepts phosphatidylglycerol (PG) to generate glycerol-di-phosphatidyl-cardiolipin (Gro-DPCL). Remarkably, in the presence of AG and PG, MhCls formed glycerol-archaetidyl-phosphatidyl-cardiolipin (Gro-APCL), an archaeal-bacterial hybrid cardiolipin species that so far has not been observed in nature. Due to the reversibility of the transesterification, in the presence of glycerol, Gro-DPCL can be converted back into two PG molecules. In the presence of other compounds that contain primary hydroxyl groups (e.g., alcohols, water, sugars), various natural and unique unnatural phospholipid species could be synthesized, including multiple di-phosphatidyl-cardiolipin species. Moreover, MhCls can utilize a glycolipid in the presence of phosphatidylglycerol to form a glycosyl-mono-phosphatidyl-cardiolipin species, emphasizing the promiscuity of this cardiolipin synthase, that could be of interest for bio-catalytic purposes

Synthetic Mimic of Antimicrobial Peptide with Nonmembrane-Disrupting Antibacterial Properties

Proteolysis in dairy lactic acid bacteria has been studied in great detail by genetic, biochemical and ultrastructural methods. From these studies the picture emerges that the proteolytic systems of lactococci and lactobacilli are remarkably similar in their components and mode of action. The proteolytic system consists of an extracellularly located serine-proteinase, transport systems specific for di-tripeptides and oligopeptides (> 3 residues), and a multitude of intracellular peptidases. This review describes the properties and regulation of individual components as well as studies that have led to identification of their cellular localization. Targeted mutational techniques developed in recent years have made it possible to investigate the role of individual and combinations of enzymes in vivo. Based on these results as well as in vitro studies of the enzymes and transporters, a model for the proteolytic pathway is proposed. The main features are: (i) proteinases have a broad specificity and are capable of releasing a large number of different oligopeptides, of which a large fraction falls in the range of 4 to 8 amino acid residues; (ii) oligopeptide transport is the main route for nitrogen entry into the cell; (iii) all peptidases are located intracellularly and concerted action of peptidases is required for complete degradation of accumulated peptides.

Effectiveness of a self-management training for patients with chronic and treatment resistant anxiety or depressive disorders on quality of life, symptoms, and empowerment : results of a randomized controlled trial

Background: Anxiety and depressive disorders are common mental disorders. A substantial part of patients does not achieve symptomatic remission after treatment in specialized services. Current care as usual (CAU) for these patients consists of long-term supportive contacts. Termination of CAU is often not considered to be an option due to persistent symptoms, a low level of functioning, and the absence of further treatment options. A new intervention, ZemCAD, offers a program focused on rehabilitation and self-management, followed by referral back to primary care. Methods: This multicenter randomized controlled trial was carried out in twelve specialized outpatient mental health care services in the Netherlands. Consenting and eligible patients were invited for the MINI interview and the baseline questionnaire. Assessments were done at 6 (T1), 12 (T2) and 18 (T3) months post baseline. We used linear mixed model analysis (LMM) to ascertain the effectiveness of the ZemCAD group relative to the CAU group on quality of life, symptom severity and empowerment. Results: In total 141 patients were included. The results at 18-month follow-up regarding to quality of life and symptom severity, showed no significant differences between the ZemCAD group and the CAU group, except on the 'social relationships'-domain (d = 0.37). With regard to empowerment a significant difference between both groups was observed in the total empowerment score and one empowerment dimension (d = 0.45 and d = 0.39, respectively). After the ZemCAD intervention, more patients went from specialized outpatient mental health services back to a less specialized health care setting with less intensive treatment, such as primary care. Conclusion: The findings in this study suggest that patients with chronic and treatment-resistant anxiety and depression using the ZemCAD intervention improve on empowerment but not on symptom severity or quality of life. Since little is known about the effects of rehabilitation and self-management in patients with chronic and treatment resistant anxiety and depressive disorders, this is a first attempt to provide a proof-of-concept study in this under-researched but important field. Trial registration: Netherlands Trial Register: NTR3335, registered 7 March 2012

Effect of Galla chinensis on growth and metabolism of microcosm biofilms

Galla chinensis extract (GCE) interferes with de- and remineralization of dental enamel and the growth and metabolism in planktonic bacteria. However, no information is available on GCE effects on biofilms formed with saliva as inoculum. The aim of the current experiments was to investigate the effects of GCE at different stages of salivary microcosm biofilm formation. Biofilms formed on glass or enamel surfaces were treated with GCE solutions at different concentrations and at different time points. Effects were assessed by lactic acid formation and colony-forming unit (CFU) counts of the biofilms. The results showed that GCE treatments inhibited growth and acid metabolism of both nascent and mature microcosm biofilms. Pretreatment of the substratum with GCE solutions inhibited growth and lactic acid production of biofilms grown on enamel, but had little effects on biofilms formed on glass surfaces. A maximum GCE effect was found when biofilms, on either surface type, were treated after 8 h of formation with 40 h of subsequent growth. In medium with sucrose-fermenting biofilms, low concentrations of GCE (0.2 and 0.1 mg/ml) inhibited acid production without killing bacteria of the biofilm. Differences were found in GCE effects on biofilms formed with saliva from different donors, with reductions in acid formation and CFU values ranging between 0 and 78%. In conclusion, bioactive components in GCE reduce or inhibit both growth and lactic acid formation in biofilms

Manipulation of saliva-derived microcosm biofilms to resemble dysbiotic subgingival microbiota

Periodontitis is a highly prevalent oral inflammatory disease triggered by dysbiotic subgingival microbiota. For the development of microbiome modulators that can reverse the dysbiotic state and reestablish a health-associated microbiota, a high-throughput in vitro multispecies biofilm model is needed. Our aim is to establish a model that resembles a dysbiotic subgingival microbial biofilm by incorporating the major periodontal pathogen Porphyromonas gingivalis into microcosm biofilms cultured from pooled saliva of healthy volunteers. The biofilms were grown for 3, 7, and 10 days and analyzed for their microbial composition by 16S rRNA gene amplicon sequencing as well as measurement of dipeptidyl peptidase IV (DPP4) activity and butyric acid production. The addition of P. gingivalis increased its abundance in saliva-derived microcosm biofilms from 2.7% on day 3 to >50% on day 10, which significantly reduced the Shannon diversity but did not affect the total number of operational taxonomic units (OTUs). The P. gingivalis-enriched biofilms displayed altered microbial composition as revealed by principal-component analysis and reduced interactions among microbial species. Moreover, these biofilms exhibited enhanced DPP4 activity and butyric acid production. In conclusion, by adding P. gingivalis to saliva-derived microcosm biofilms, we established an in vitro pathogenenriched dysbiotic microbiota which resembles periodontitis-associated subgingival microbiota in terms of increased P. gingivalis abundance and higher DPP4 activity and butyric acid production. This model may allow for investigating factors that accelerate or hinder a microbial shift from symbiosis to dysbiosis and for developing microbiome modulation strategies