253 research outputs found

    An in vitro system to study drug sensitivity of Mycobacterium leprae using infected human tissue

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    A reliable screening technique for assessing the sensitivity of Mycobacterium leprae to drugs has been developed. The method is based on the susceptibility or otherwise of M. leprae- infected tissues from lepromatous leprosy patients to the action of diaminodiphenyl sulphone (dapsone) or rifampicin on the incorporation of [14C]-acetate into lipids. The extent of inhibition or lack of inhibition correlated very well with the drug sensitivity or resistance of the bacteria isolated from the patients to the above drugs. A similar trend was observed when the incorporation into individual fractions of neutral lipids was measured. There was no incorporation by heat-killed tissues. This method correlates well with the 3,4-dihydroxyphenylalanine uptake studies

    Microscopic Analysis For Water Stressed By High Electric Fields In The Prebreakdown Regime

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    Analysis of the electrical double layer at the electrode-water interface for voltages close to the breakdown point has been carried out based on a static, Monte Carlo approach. It is shown that strong dipole realignment, ion-ion correlation, and finite-size effects can greatly modify the electric fields and local permittivity (hence, leading to optical structure) at the electrode interface. Dramatic enhancements of Schottky injection, providing a source for electronic controlled breakdown, are possible. It is also shown that large pressures associated with the Maxwell stress tensor would be created at the electrode boundaries. Our results depend on the ionic density, and are in keeping with recent observations. A simple, perturbative analysis shows that high field regions with a sharp variation in permittivity can potentially be critical spots for instability initiation. This suggests that the use of polished electrodes, or composite materials, or alternative nonpolar liquids might help enhance high-voltage operation

    Associations Between Brain Structure and Connectivity in Infants and Exposure to Selective Serotonin Reuptake Inhibitors During Pregnancy

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    Importance Selective serotonin reuptake inhibitor (SSRI) use among pregnant women is increasing, yet the association between prenatal SSRI exposure and fetal neurodevelopment is poorly understood. Animal studies show that perinatal SSRI exposure alters limbic circuitry and produces anxiety and depressive-like behaviors after adolescence, but literature on prenatal SSRI exposure in humans is limited and mixed. Objective To examine associations between prenatal SSRI exposure and brain development using structural and diffusion magnetic resonance imaging (MRI). Design, Setting, and Participants A cohort study conducted at Columbia University Medical Center and New York State Psychiatric Institute included 98 infants: 16 with in utero SSRI exposure, 21 with in utero untreated maternal depression exposure, and 61 healthy controls. Data were collected between January 6, 2011, and October 25, 2016. Exposures Selective serotonin reuptake inhibitors and untreated maternal depression. Main Outcomes and Measures Gray matter volume estimates using structural MRI with voxel-based morphometry and white matter structural connectivity (connectome) using diffusion MRI with probabilistic tractography. Results The sample included 98 mother (31 [32%] white, 26 [27%] Hispanic/Latina, 26 [27%] black/African American, 15 [15%] other) and infant (46 [47%] boys, 52 [53%] girls) dyads. Mean (SD) age of the infants at the time of the scan was 3.43 (1.50) weeks. Voxel-based morphometry showed significant gray matter volume expansion in the right amygdala (Cohen d = 0.65; 95% CI, 0.06-1.23) and right insula (Cohen d = 0.86; 95% CI, 0.26-1.14) in SSRI-exposed infants compared with both healthy controls and infants exposed to untreated maternal depression (P < .05; whole-brain correction). In connectome-level analysis of white matter structural connectivity, the SSRI group showed a significant increase in connectivity between the right amygdala and the right insula with a large effect size (Cohen d = 0.99; 95% CI, 0.40-1.57) compared with healthy controls and untreated depression (P < .05; whole connectome correction). Conclusions and Relevance Our findings suggest that prenatal SSRI exposure has an association with fetal brain development, particularly in brain regions critical to emotional processing. The study highlights the need for further research on the potential long-term behavioral and psychological outcomes of these neurodevelopmental changes

    Electrical Network-Based Time-Dependent Model of Electrical Breakdown in Water

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    A time-dependent, two-dimensional, percolative approach to model dielectric breakdown based on a network of parallel resistor–capacitor elements having random values, has been developed. The breakdown criteria rely on a threshold electric field and on energy dissipation exceeding the heat of vaporization. By carrying out this time-dependent analysis, the development and propagation of streamers and prebreakdown dynamical evolution have been obtained directly. These model simulations also provide the streamer shape, characteristics such as streamer velocity, the prebreakdown delay time, time-dependent current, and relationship between breakdown times, and applied electric fields for a given geometry. The results agree well with experimental data and reports in literature. The time to breakdown (tbr) for a 100 μm water gap has been shown to be strong function of the applied bias, with a 15–185 ns range. It is also shown that the current is fashioned not only by dynamic changes in local resistance, but that capacitive modifications arising from vaporization and streamer development also affect the transient behavior

    Evidence-Based Guideline on Laparoscopy in Pregnancy: Commissioned by the British Society for Gynaecological Endoscopy (BSGE) Endorsed by the Royal College of Obstetricians & Gynaecologists (RCOG).

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    Laparoscopy is widely utilised to diagnose and treat acute and chronic, gynaecological and general surgical conditions. It has only been in recent years that laparoscopy has become an acceptable surgical alternative to open surgery in pregnancy. To date there is little clinical guidance pertaining to laparoscopic surgery in pregnancy. This is why the BSGE commissioned this guideline. MEDLINE, EMBASE, CINAHL and the Cochrane library were searched up to February 2017 and evidence was collated and graded following the NICE-approved process. The conditions included in this guideline are laparoscopic management of acute appendicitis, acute gall bladder disease and symptomatic benign adnexal tumours in pregnancy. The intended audience for this guideline is obstetricians and gynaecologists in secondary and tertiary care, general surgeons and anaesthetists. However, only laparoscopists who have adequate laparoscopic skills and who perform complex laparoscopic surgery regularly should undertake laparoscopy in pregnant women, since much of the evidence stems from specialised centres

    Decoding Unattended Fearful Faces with Whole-Brain Correlations: An Approach to Identify Condition-Dependent Large-Scale Functional Connectivity

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    Processing of unattended threat-related stimuli, such as fearful faces, has been previously examined using group functional magnetic resonance (fMRI) approaches. However, the identification of features of brain activity containing sufficient information to decode, or “brain-read”, unattended (implicit) fear perception remains an active research goal. Here we test the hypothesis that patterns of large-scale functional connectivity (FC) decode the emotional expression of implicitly perceived faces within single individuals using training data from separate subjects. fMRI and a blocked design were used to acquire BOLD signals during implicit (task-unrelated) presentation of fearful and neutral faces. A pattern classifier (linear kernel Support Vector Machine, or SVM) with linear filter feature selection used pair-wise FC as features to predict the emotional expression of implicitly presented faces. We plotted classification accuracy vs. number of top N selected features and observed that significantly higher than chance accuracies (between 90–100%) were achieved with 15–40 features. During fearful face presentation, the most informative and positively modulated FC was between angular gyrus and hippocampus, while the greatest overall contributing region was the thalamus, with positively modulated connections to bilateral middle temporal gyrus and insula. Other FCs that predicted fear included superior-occipital and parietal regions, cerebellum and prefrontal cortex. By comparison, patterns of spatial activity (as opposed to interactivity) were relatively uninformative in decoding implicit fear. These findings indicate that whole-brain patterns of interactivity are a sensitive and informative signature of unattended fearful emotion processing. At the same time, we demonstrate and propose a sensitive and exploratory approach for the identification of large-scale, condition-dependent FC. In contrast to model-based, group approaches, the current approach does not discount the multivariate, joint responses of multiple functional connections and is not hampered by signal loss and the need for multiple comparisons correction

    A molecular assay for sensitive detection of pathogen-specific T-cells.

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    Here we describe the development and validation of a highly sensitive assay of antigen-specific IFN-γ production using real time quantitative PCR (qPCR) for two reporters--monokine-induced by IFN-γ (MIG) and the IFN-γ inducible protein-10 (IP10). We developed and validated the assay and applied it to the detection of CMV, HIV and Mycobacterium tuberculosis (MTB) specific responses, in a cohort of HIV co-infected patients. We compared the sensitivity of this assay to that of the ex vivo RD1 (ESAT-6 and CFP-10)-specific IFN-γ Elispot assay. We observed a clear quantitative correlation between the two assays (P<0.001). Our assay proved to be a sensitive assay for the detection of MTB-specific T cells, could be performed on whole blood samples of fingerprick (50 uL) volumes, and was not affected by HIV-mediated immunosuppression. This assay platform is potentially of utility in diagnosis of infection in this and other clinical settings

    Schizophrenia copy number variants and associative learning

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    Large-scale genomic studies have made major progress in identifying genetic risk variants for schizophrenia. A key finding from these studies is that there is an increased burden of genomic copy number variants (CNVs) in schizophrenia cases compared with controls. The mechanism through which these CNVs confer risk for the symptoms of schizophrenia, however, remains unclear. One possibility is that schizophrenia risk CNVs impact basic associative learning processes, abnormalities of which have long been associated with the disorder. To investigate whether genes in schizophrenia CNVs impact on specific phases of associative learning we combined human genetics with experimental gene expression studies in animals. In a sample of 11 917 schizophrenia cases and 16 416 controls, we investigated whether CNVs from patients with schizophrenia are enriched for genes expressed during the consolidation, retrieval or extinction of associative memories. We show that CNVs from cases are enriched for genes expressed during fear extinction in the hippocampus, but not genes expressed following consolidation or retrieval. These results suggest that CNVs act to impair inhibitory learning in schizophrenia, potentially contributing to the development of core symptoms of the disorder

    Motivational determinants among physicians in Lahore, Pakistan

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    Introduction: Human resource crises in developing countries have been identified as a critical aspect of poor quality and low accessibility in health care. Worker motivation is an important facet of this issue. Specifically, motivation among physicians, who are an important bridge between health systems and patients, should be considered. This study aimed to identify the determinants of job motivation among physicians, a neglected perspective, especially in developing countries. Methods: A stratified random sample of 360 physicians was selected from public primary, public secondary and public and private tertiary health facilities in the Lahore district, Pakistan. Pretested, semi-structured, self-administered questionnaires were used. For the descriptive part of this study, physicians were asked to report their 5 most important work motivators and demotivators within the context of their current jobs and in general. Responses were coded according to emergent themes and frequencies calculated. Of the 30 factors identified, 10 were classified as intrinsic, 16 as organizational and 4 as socio-cultural. Results: Intrinsic and socio-cultural factors like serving people, respect and career growth were important motivators. Conversely, demotivators across setups were mostly organizational, especially in current jobs. Among these, less pay was reported the most frequently. Fewer opportunities for higher qualifications was a demotivator among primary and secondary physicians. Less personal safety and poor working conditions were important in the public sector, particularly among female physicians. Among private tertiary physicians financial incentives other than pay and good working conditions were motivators in current jobs. Socio-cultural and intrinsic factors like less personal and social time and the inability to financially support oneself and family were more important among male physicians. Conclusion: Motivational determinants differed across different levels of care, sectors and genders. Nonetheless, the important motivators across setups in this study were mostly intrinsic and socio-cultural, which are difficult to affect while the demotivators were largely organizational. Many can be addressed even at the facility level such as less personal safety and poor working conditions. Thus, in resource limited settings a good strategic starting point could be small scale changes that may markedly improve physicians' motivation and subsequently the quality of health care
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