Confirmatory Factor Analysis of the WHO Violence Against Women Instrument in Pregnant Women: Results from the BRISA Prenatal Cohort

Background

Screening for violence during pregnancy is one of the strategies for the prevention of abuse against women. Since violence is difficult to measure, it is necessary to validate questionnaires that can provide a good measure of the phenomenon. The present study analyzed the psychometric properties of the World Health Organization Violence Against Women (WHO VAW) instrument for the measurement of violence against pregnant women.

Methods

Data from the Brazilian Ribeirão Preto and São Luís birth cohort studies (BRISA) were used. The sample consisted of 1,446 pregnant women from São Luís and 1,378 from Ribeirão Preto, interviewed in 2010 and 2011. Thirteen variables were selected from a self-applied questionnaire. Confirmatory factor analysis was used to investigate whether violence is a uni-or-multidimensional construct consisting of psychological, physical and sexual dimensions. The mean-and-variance-adjusted weighted least squares estimator was used. Models were fitted separately for each city and a third model combining data from the two settings was also tested. Models suggested from modification indices were tested to determine whether changes in the WHO VAW model would produce a better fit.

Results

The unidimensional model did not show good fit (Root mean square error of approximation [RMSEA]  = 0.060, p<0.001 for the combined model). The multidimensional WHO VAW model showed good fit (RMSEA = 0.036, p = 0.999 for the combined model) and standardized factor loadings higher than 0.70, except for the sexual dimension for SL (0.65). The models suggested by the modification indices with cross loadings measuring simultaneously physical and psychological violence showed a significantly better fit compared to the original WHO model (p<0.001 for the difference between the model chi-squares).

Conclusions

Violence is a multidimensional second-order construct consisting of psychological, physical and sexual dimensions. The WHO VAW model and the modified models are suitable for measuring violence against pregnant women.     

Unique biological properties of Mycobacterium tuberculosis L-form variants: impact for survival under stress

Bacteria can, under certain conditions, enter into a cell-less state known as L-form conversion. This phenomenon is universal, but also recognized with difficultly by microbiologists. The current study addresses several aspects concerning the ability of tubercle bacilli to use L-form conversion as a unique adaptive strategy to survive and reproduce under unfavorable conditions. Nutrient starvation of M. tuberculosis in vitro followed by passages in Middlebrook 7H9 semisolid medium was used for stress induction and the selective isolation of mycobacterial L-form variants. Light and electron microscopy images evidence the peculiar characteristics of mycobacterial L-forms. For example, mycobacterial L-forms were observed to lose their acid-fastness and change their morphology. In addition, wide morphological variability, the presence of large and elementary bodies, coccoids and small granular forms, as well as the appearance of unusual modes of irregular cell division were observed. Unlike classical tubercle bacilli, L-form variants grew and developed typical "fried-egg" colonies faster. L-forms were verified as M. tuberculosis by spoligotyping. The results provide insights into the nature of L-form phenomena in M. tuberculosis and link them to the mechanisms allowing mycobacterial survival under stress.     

GHOST: global hepatitis outbreak and surveillance technology

Background

Hepatitis C is a major public health problem in the United States and worldwide. Outbreaks of hepatitis C virus (HCV) infections associated with unsafe injection practices, drug diversion, and other exposures to blood are difficult to detect and investigate. Effective HCV outbreak investigation requires comprehensive surveillance and robust case investigation. We previously developed and validated a methodology for the rapid and cost-effective identification of HCV transmission clusters. Global Hepatitis Outbreak and Surveillance Technology (GHOST) is a cloud-based system enabling users, regardless of computational expertise, to analyze and visualize transmission clusters in an independent, accurate and reproducible way.

Results

We present and explore performance of several GHOST implemented algorithms using next-generation sequencing data experimentally obtained from hypervariable region 1 of genetically related and unrelated HCV strains. GHOST processes data from an entire MiSeq run in approximately 3 h. A panel of seven specimens was used for preparation of six repeats of MiSeq libraries. Testing sequence data from these libraries by GHOST showed a consistent transmission linkage detection, testifying to high reproducibility of the system. Lack of linkage among genetically unrelated HCV strains and constant detection of genetic linkage between HCV strains from known transmission pairs and from follow-up specimens at different levels of MiSeq-read sampling indicate high specificity and sensitivity of GHOST in accurate detection of HCV transmission.

Conclusions

GHOST enables automatic extraction of timely and relevant public health information suitable for guiding effective intervention measures. It is designed as a virtual diagnostic system intended for use in molecular surveillance and outbreak investigations rather than in research. The system produces accurate and reproducible information on HCV transmission clusters for all users, irrespective of their level of bioinformatics expertise. Improvement in molecular detection capacity will contribute to increasing the rate of transmission detection, thus providing opportunity for rapid, accurate and effective response to outbreaks of hepatitis C. Although GHOST was originally developed for hepatitis C surveillance, its modular structure is readily applicable to other infectious diseases. Worldwide availability of GHOST for the detection of HCV transmissions will foster deeper involvement of public health researchers and practitioners in hepatitis C outbreak investigation.

     

Combining data sharing with the master–worker paradigm in the common component architecture

Software component technologies are being accepted as an adequate solution for handling the complexity of applications. However, existing software component models tend to be specialized to some types of resource architectures (e.g. in-process, distributed environments, etc.) and/or do not provide a very high level of abstraction. This paper focuses on handling data sharing on operation invocations between components as a solution allowing applications to be efficiently executed on all kinds of resources. In particular, the data sharing pattern appears in master–worker applications, when workers need to access only a part of a large piece of data, either in read or write mode. This approach is applied to the Common Component Architecture model. Its benefits are discussed using an image rendering application.

Identification, synthesis and properties of a consensus peptide recognized by a monoclonal antibody directed to various type I cytokine receptors

Previous works demonstrated that the monoclonal antibody (MAb) called R7B4 is directed to an epitope shared by receptors for lactogenic and somatogenic hormones as well as interleukins 2 and 6 (IL-2 and IL-6). The MAb inhibited the biological effects of those hormones and cytokines by impairing their binding to receptors. It is known that the receptors for growth hormones (GH), prolactins (PRL), IL-2, and IL-6 pertain to the type I cytokine receptor family, sharing the common motif WSXWS or the homologous F(Y)GEFS. Thus, a set of 34 decapeptides corresponding to diverse receptors containing those sequences were synthesized by the PEPSCAN method and their reactions with MAb R7B4 were measured by ELISA. The MAb significantly recognized 21 peptides, allowing us to establish the consensus sequence HGYWSEWSPE as a portion of the R7B4 epitope. The consensus peptide was synthesized and purified by conventional methods, and its capacity to bind to MAb R7B4 paratope confirmed. Moreover, polyclonal Ab to the peptide elicited in mice were able to inhibit the hGH binding to lactogenic, somatogenic and human specific liver receptors. This fact suggests that the consensus peptide could be used as an immunogen to produce anti-hGH receptor Ab behaving as hormone or cytokine antagonists in certain pathological conditions.     

Phase separation liquid-liquid extraction for the quantification of 8-iso-Prostaglandin F2 Alpha in human plasma by LC-MS/MS

BackgroundReactive oxygen species (ROS) are produced in the body during normal metabolism by means of enzymes and non-enzymatic chemical reduction of molecular oxygen. In case of the prevalence of ROS formation over their elimination, highly reactive free radicals can be accumulated and can cause multiple damages to the biomolecules and cells. Determination of isoprostanes in biological matrices is most often used to register free radical damage and requires selective, sensitive and specific techniques.MethodsThis study presents the development and validation of the LC-MS/MS method for the determination of 8-iso-Prostaglandin F2α in human plasma utilising a modified liquid-liquid extraction procedure with phase separation.ResultsModified sample preparation procedure assured higher extraction yield, clear separation of organic layer from the plasma water phase and protein precipitates, and better-purified product for instrumental analysis. Linearity was validated in the range 0.1-5.0 µg/L with R2 > 0.996; normalised matrix varied between 86.0% and 108.3%, accuracy ranged from 90.4 % to 113.9% and precision both within runs and between runs was less than 7%. With a run time of 10 min, a throughput of over 50 samples per working day could be performed.ConclusionsThe method meets all the current industrial validation criteria and allows the accurate and precise determination of 8-iso-PGF2α in human plasma at diagnostically significant concentration range.     

Effect of genomic rearrangement on heavy metal tolerance in the plant-growth-promoting rhizobacterium <Emphasis Type="Italic">Azospirillum brasilense</Emphasis> Sp245

A derivative of Azospirillum brasilense Sp245, Sp245.5, which spontaneously lost 85 and 120 MDa replicons upon the formation of a new megaplasmid, has been shown to produce a novel lipopolysaccharide and to lose Calcofluor-binding polysaccharides. As compared to Sp245, the derivative displays notably increased heavy metal tolerance. The phenotypes of Sp245 and Sp245.5 are characterized by the following minimal inhibitory concentrations (MICs) of heavy metals: 0.5 and 0.9 μmol l⁻¹ of Ag⁺, 0.4 and 0.7 mmol l⁻¹ of Co²⁺, 0.9 and 4.7 mmol l⁻¹ of Cu²⁺, and 3.1 and 11.5 mmol l⁻¹ of Zn²⁺, respectively. In Sp245, in the presence of a nonlethal concentration (0.625 μmol l⁻¹) of the efflux pump inhibitor carbonyl cyanide m-chlorophenylhydrazone (CCCP), the MIC of cobalt, copper, and zinc drop 1.3- to 1.6-fold, but the low tolerance to silver is unaffected. In Sp245.5, CCCP does not affect cobalt tolerance, suppresses tolerance to copper and silver to the wild-type levels, and causes a 1.4-fold decrease in resistance to zinc. Therefore, significant elevation of heavy metal tolerance in Sp245.5 seems caused by the induction/overexpression of the proton-dependent efflux of certain metal ions. The novel cell surface and other unknown factors could also be responsible for the increased tolerance of A. brasilense Sp245.5 to heavy metals.     

An ultraviolet spectrophotometric assay for the screening of sn-2-specific lipases using 1,3-O-dioleoyl-2-O-α-eleostearoyl-sn-glycerol as substrate

In the present study, we propose a continuous assay for the screening of sn-2 lipases by using triacylglycerols (TAGs) from Aleurites fordii seed (tung oil) and a synthetic TAG containing the α-eleostearic acid at the sn-2 position and the oleic acid (OA) at the sn-1 and sn-3 positions [1,3-O-dioleoyl-2-O-α-eleostearoyl-sn-glycerol (sn-OEO)]. Each TAG was coated into a microplate well, and the lipase activity was measured by optical density increase at 272 nm due to transition of α-eleostearic acid from the adsorbed to the soluble state. The sn-1,3-regioselective lipases human pancreatic lipase (HPL), LIP2 lipase from Yarrowia lipolytica (YLLIP2), and a known sn-2 lipase, Candida antarctica lipase A (CALA) were used to validate this method. TLC analysis of lipolysis products showed that the lipases tested were able to hydrolyze the sn-OEO and the tung oil TAGs, but only CALA hydrolyzed the sn-2 position. The ratio of initial velocities on sn-OEO and tung oil TAGs was used to estimate the sn-2 preference of lipases. CALA was the enzyme with the highest ratio (0.22 ± 0.015), whereas HPL and YLLIP2 showed much lower ratios (0.072 ± 0.026 and 0.038 ± 0.016, respectively). This continuous sn-2 lipase assay is compatible with a high sample throughput and thus can be applied to the screening of sn-2 lipases.