Calibrating saturated conductivity and soil cohesion in rainfall-triggered landslides in the Langhe area (1994)

In this work we have analyzed a “cold case”, i.e., the prolonged rainfall and flood event occurred in the Piedmont region (Northern Italy) in November 1994, causing several hundred of shallow landslides. The research aim is to put some focus on the possibility to calibrate soil parameters by means of the combined use of a simple hydrological model (Rosso et al. 2006) and post-event geotechnical surveys. For this purpose, a database of geometries and soil characteristics for 238 observed landslides has been used. To address the calibration of the cohesion and hydraulic conductivity parameters, the safety factor expression from the Limit Equilibrium Analysis has been targeted to assume a maximum value of 1 for all the slopes made unstable by the actual (measured) rainfall. Significant reduction of the cohesion parameter was observed after calibration, suggesting caution in the use of literature values, typically obtained on mechanically undisturbed soil sample

Estimating diagnostic accuracy of tests for latent tuberculosis infection without a gold standard among healthcare workers

Binary file ES_Abstracts_Final_ECDC.txt matche

Methylated HBHA Produced in M. smegmatis Discriminates between Active and Non-Active Tuberculosis Disease among RD1-Responders

A challenge in tuberculosis (TB) research is to develop a new immunological test that can help distinguish, among subjects responsive to QuantiFERON TB Gold In tube (QFT-IT), those who are able to control Mtb replication (remote LTBI, recent infection and past TB) from those who cannot (active TB disease). IFN-\u3b3 response to the Heparin-binding-hemagglutinin (HBHA) of Mtb has been associated with LTBI, but the cumbersome procedures of purifying the methylated and immunological active form of the protein from Mtb or M. bovis Bacillus Calmette et Guerin (BCG) have prevented its implementation in a diagnostic test. Therefore, the aim of the present study was to evaluate the IFN-\u3b3 response to methylated HBHA of Mtb produced in M. smegmatis (rHBHAms) in individuals at different stages of TB who scored positive to QFT-IT

Methylated HBHA produced in <i>M. smegmatis</i> discriminates between active and non-active tuberculosis disease among RD1-responders

Background. A challenge in tuberculosis (TB) research is to develop a new immunological test that can help distinguish, among subjects responsive to QuantiFERON TB Gold In tube (QFT-IT), those who are able to control Mtb replication (remote LTBI, recent infection and past TB) from those who cannot (active TB disease). IFN-γ; response to the Heparin-binding-hemagglutinin (HBHA) of Mtb has been associated with LTBI, but the cumbersome procedures of purifying the methylated and immunological active form of the protein from Mtb or M. bovis Bacillus Calmette et Guerin (BCG) have prevented its implementation in a diagnostic test. Therefore, the aim of the present study was to evaluate the IFN-γ response to methylated HBHA of Mtb produced in M. smegmatis (rHBHAms) in individuals at different stages of TB who scored positive to QFT-IT. Methodology/Principal Findings. 87 individuals at different stages of TB who scored positive to QFT-IT were selected. IFN-γ response to in vitro whole blood stimulation with rHBHAms was evaluated by short-term and long-term tests and detected by ELISA or flow cytometry. We demonstrated that the IFN-γ response to rHBHAms is mediated by CD4+ T-cells with an effector-memory phenotype. This response, evaluated by short-term-tests, is significantly lower in active TB than in remote LTBI (p = 0.0010) and past TB (p = 0.0152). These results were confirmed by long-term tests. The qualitative data confirmed that IFN-γ responses higher than the cut-off point identified by ROC analysis are associated with the status of non-active disease. Conclusions. In this study we show that the T-cell response to a recombinant and methylated HBHA of Mtb produced in M. smegmatis is useful to discriminate between active and non-active TB disease among those responsive to QFT-IT in a whole blood system. Further studies are needed to improve the accuracy of the assay

New tools for detecting latent tuberculosis infection: evaluation of RD1-specific long-term response

<p>Abstract</p> <p>Background</p> <p>Interferon-gamma (IFN-γ) release assays (IGRAs) were designed to detect latent tuberculosis infection (LTBI). However, discrepancies were found between the tuberculin skin test (TST) and IGRAs results that cannot be attributed to prior Bacille Calmètte Guerin vaccinations. The aim of this study was to evaluate tools for improving LTBI diagnosis by analyzing the IFN-γ response to RD1 proteins in prolonged (long-term response) whole blood tests in those subjects resulting negative to assays such as QuantiFERON-TB Gold In tube (QFT-IT).</p> <p>Methods</p> <p>The study population included 106 healthy TST⁺individuals with suspected LTBI (recent contact of smear-positive TB and homeless) consecutively enrolled. As controls, 13 healthy subjects unexposed to <it>M. tuberculosis </it>(TST^-, QFT-IT^-) and 29 subjects with cured pulmonary TB were enrolled. IFN-γ whole blood response to RD1 proteins and QFT-IT were evaluated at day 1 post-culture. A prolonged test evaluating long-term IFN-γ response (7-day) to RD1 proteins in diluted whole blood was performed.</p> <p>Results</p> <p>Among the enrolled TST⁺subjects with suspected LTBI, 70/106 (66.0%) responded to QFT-IT and 64/106 (60.3%) to RD1 proteins at day 1. To evaluate whether a prolonged test could improve the detection of LTBI, we set up the test using cured TB patients (with a microbiologically diagnosed past pulmonary disease) who resulted QFT-IT-negative and healthy controls as comparator groups. Using this assay, a statistically significant difference was found between IFN-γ levels in cured TB patients compared to healthy controls (p < 0.006). Based on these data, we constructed a receiver operating characteristic (ROC) curve and we calculated a cut-off. Based on the cut-off value, we found that among the 36 enrolled TST+ subjects with suspected LTBI not responding to QFT-IT, a long term response to RD1 proteins was detected in 11 subjects (30.6%).</p> <p>Conclusion</p> <p>These results indicate that IFN-γ long-term response to <it>M. tuberculosis </it>RD1 antigens may be used to detect past infection with <it>M. tuberculosis </it>and may help to identify additional individuals with LTBI who resulted negative in the short-term tests. These data may provide useful information for improving immunodiagnostic tests for tuberculosis infection, especially in individuals at high risk for active TB.</p