A Toolbox for Tuberculosis Diagnosis: An Indian Multicentric Study (2006-2008): Microbiological Results

BACKGROUND: The aim of this multicentric prospective study in India was to assess the value of several microbiological tools that contribute to the diagnosis of tuberculosis (TB) according to HIV status. METHODS: Standard microbiological tools on individual specimens were analyzed. RESULTS: Among the 807 patients with active TB, 131 were HIV-infected, 316 HIV-uninfected and 360 had HIV-unknown status. Among the 980 non-active TB subjects, 559 were at low risk and 421 were at high risk of M. tuberculosis (Mtb) exposure. Sensitivity of smear microscopy (SM) was significantly lower in HIV-infected (42.2%) than HIV-uninfected (75.9%) (p = 0.0001) and HIV-unknown pulmonary TB patients (61.4%) (p = 0.004). Specificity was 94.5% in non-TB patients and 100% in health care workers (HCW) and healthy family contacts. Automated liquid culture has significantly higher diagnostic performances than solid culture, measured by sensitivity (74.7% vs. 55.9%) (p = 0.0001) and shorter median time to detection (TTD) (12.0 vs. 34.0 days) (p = 0.0001). Specificity was 100% in HCW and cured-TB patients, but was lower in non-TB patients (89%) due to isolation of Mycobacteria other than tuberculosis (MOTT). TTD by both methods was related to AFB score. Contamination rate was low (1.4%). AccuProbe hybridization technique detected Mtb in almost all culture-positive specimens, but MOTT were found in 4.7% with a significantly higher frequency in HIV-infected (15%) than HIV-uninfected TB patients (0.5%) (p = 0.0007). Pre-test classification significantly increased the diagnostic value of all microbiological tests in pulmonary TB patients (p<0.0001) but to a lesser degree in extrapulmonary TB patients. CONCLUSIONS: Conventional microbiological tools led to results similar to those already described in India special features for HIV-infected TB patients included lower detection by SM and culture. New microbiological assays, such as the automated liquid culture system, showed increased accuracy and speed of detection

Dielectric disorder in two-dimensional materials

Understanding and controlling disorder is key to nanotechnology and materials science. Traditionally, disorder is attributed to local fluctuations of inherent material properties such as chemical and structural composition, doping or strain. Here, we present a fundamentally new source of disorder in nanoscale systems that is based entirely on the local changes of the Coulomb interaction due to fluctuations of the external dielectric environment. Using two-dimensional semiconductors as prototypes, we experimentally monitor dielectric disorder by probing the statistics and correlations of the exciton resonances, and theoretically analyse the influence of external screening and phonon scattering. Even moderate fluctuations of the dielectric environment are shown to induce large variations of the bandgap and exciton binding energies up to the 100 meV range, often making it a dominant source of inhomogeneities. As a consequence, dielectric disorder has strong implications for both the optical and transport properties of nanoscale materials and their heterostructures

Spatial regulation of the glycocalyx component podocalyxin is a switch for prometastatic function

The glycocalyx component and sialomucin podocalyxin (PODXL) is required for normal tissue development by promoting apical membranes to form between cells, triggering lumen formation. Elevated PODXL expression is also associated with metastasis and poor clinical outcome in multiple tumor types. How PODXL presents this duality in effect remains unknown. We identify an unexpected function of PODXL as a decoy receptor for galectin-3 (GAL3), whereby the PODXL-GAL3 interaction releases GAL3 repression of integrin-based invasion. Differential cortical targeting of PODXL, regulated by ubiquitination, is the molecular mechanism controlling alternate fates. Both PODXL high and low surface levels occur in parallel subpopulations within cancer cells. Orthotopic intraprostatic xenograft of PODXL-manipulated cells or those with different surface levels of PODXL define that this axis controls metastasis in vivo. Clinically, interplay between PODXL-GAL3 stratifies prostate cancer patients with poor outcome. Our studies define the molecular mechanisms and context in which PODXL promotes invasion and metastasis

Synthesis, antibacterial and antifungal activity of 2-amino-1,4-naphthoquinones using silica-supported perchloric acid (HClO₄-SiO₂) as a mild, recyclable and highly efficient heterogeneous catalyst^{<span style="mso-ansi-language:FR" lang="FR">†</span>}

1431-1440Perchloric acid adsorbed on silica gel (1 mol%) has been found to be an efficient and recyclable heterogeneous catalyst for rapid conjugate addition of primary and secondary amines with 1,4-naphthoquinone to afford 2-amino-1,4-naphthoquinones under ultrasonication in moderate to high yields without using any solvent. The compounds tested for in vitro antimicrobial activity have shown high antibacterial activity against Gram positive bacteria Bacillus subtilis, <i style="mso-bidi-font-style: normal">Micrococcus luteus, Staphylococcus aureus as compared to Gram negative bacteria <i style="mso-bidi-font-style: normal">Burkholderia cepacia, Escherichia coli, Enterobacter cloacae, Klebseilla pneumoniae and Pseudomonas aeruginosa. High antifungal activity has been observed against Candida albicans and Issatchenkia orientalis for all the compounds.<span style="mso-bidi-font-weight:bold; mso-bidi-font-style:italic" lang="EN-GB"> </span

Overlapping targets exist between the Par-4 and miR-200c axis which regulate EMT and proliferation of pancreatic cancer cells

The last decade has witnessed a substantial expansion in the field of microRNA (miRNA) biology, providing crucial insights into the role of miRNAs in disease pathology, predominantly in cancer progression and its metastatic spread. The discovery of tumor-suppressing miRNAs represents a potential approach for developing novel therapeutics. In this context, through miRNA microarray analysis, we examined the consequences of Prostate apoptosis response-4 (Par-4), a well-established tumor-suppressor, stimulation on expression of different miRNAs in Panc-1 cells. The results strikingly indicated elevated miR-200c levels in these cells upon Par-4 overexpression. Intriguingly, the Reverse Phase Protein Array (RPPA) analysis revealed differentially expressed proteins (DEPs), which overlap between miR200c- and Par-4-transfected cells, highlighting the cross-talks between these pathways. Notably, Phospho-p44/42 MAPK; Bim; Bcl-xL; Rb Phospho-Ser807, Ser811; Akt Phospho-Ser473; Smad1/5 Phospho-Ser463/Ser465 and Zyxin scored the most significant DEPs among the two data sets. Furthermore, the GFP-Par-4-transfected cells depicted an impeded expression of critical mesenchymal markers viz. TGF-β1, TGF-β2, ZEB-1, and Twist-1, concomitant with augmented miR-200c and E-cadherin levels. Strikingly, while Par-4 overexpression halted ZEB-1 at the transcriptional level; contrarily, silencing of endogenous Par-4 by siRNA robustly augmented the Epithelial-mesenchymal transition (EMT) markers, along with declining miR-200c levels. The pharmacological Par-4-inducer, NGD16, triggered Par-4 expression which corresponded with increased miR-200c resulting in the ZEB-1 downregulation. Noteworthily, tumor samples obtained from the syngenic mouse pancreatic cancer model revealed elevated miR-200c levels in the NGD16-treated mice that positively correlated with the Par-4 and E-cadherin levels in vivo; while a negative correlation was evident with ZEB-1 and Vimentin

Natural podophyllotoxin analog 4DPG attenuates EMT and colorectal cancer progression via activation of checkpoint kinase 2

Epithelial–mesenchymal transition (EMT) is critical for the metastatic dissemination of cancer cells and contributes to drug resistance. In this study, we observed that epithelial colorectal cancer (CRC) cells transiently exposed to 5-fluorouracil (5-FU) (a chemotherapeutic drug for CRC) as well as 5-FU-resistant cells (5-FU-R) develop EMT characters as evidenced by activation of Vimentin and augmented invasive properties. On the other hand, 4DPG (4′-demethyl-deoxypodophyllotoxin glucoside), a natural podophyllotoxin analog attenuates EMT and invadopodia formation abilities of HCT-116/5-FU-R and SW-620/5-FU-R cells. Treatment with 4DPG restrains Vimentin phosphorylation (Ser38) in 5-FU-R cells, along with downregulation of mesenchymal markers Twist1 and MMP-2 while augmenting the expression of epithelial markers E-cadherin and TIMP-1. Moreover, 4DPG boosts the tumor-suppressor protein, checkpoint kinase 2 (Chk2) via phosphorylation at Thr68 in a dose-dependent manner in 5-FU-R cells. Mechanistically, SiRNA-mediated silencing of Chk2, as well as treatment with Chk2-specific small-molecule inhibitor (PV1019), divulges that 4DPG represses Vimentin activation in a Chk2-dependent manner. Furthermore, immunoprecipitation analysis unveiled that 4DPG prevents complex formation between Vimentin and p53 resulting in the rescue of p53 and its nuclear localization in aggressive 5-FU-R cells. In addition, 4DPG confers suitable pharmacokinetic properties and strongly abrogates tumor growth, polyps formation, and lung metastasis in an orthotopic rat colorectal carcinoma model. In conclusion, our findings demonstrate 4DPG as a targeted antitumor/anti-metastatic pharmacological lead compound to circumvent EMT-associated drug resistance and suggest its clinical benefits for the treatment of aggressive cancers

Constitutive expression of SMAR1 confers susceptibility to Mycobacterium tuberculosis infection in a transgenic mouse model

Background & objectives: Studies involving animal models of experimental tuberculosis have elucidated the predominant role of cytokines secreted by T cells and macrophages to be an essential component of the immune response against Mycobacterium tuberculosis infection. The immune activities of CD4+ T cells are mediated in part by Th1 cytokine interferon gamma (IFN-γ) which is produced primarily by T cells and natural killer (NK) cells and critical for initiating the immune response against intracellular pathogen such as M. tuberculosis. Nuclear matrix protein SMAR1 plays an important role in V(D)J recombination, T helper cell differentiation and inflammatory diseases. In this study a transgenic mouse model was used to study the role of SMAR1 in M. tuberculosis infection. Methods: Wild type BALB/c, C57BL/6, BALB/c-EGFP-SMAR1 and C57BL/6-SMAR1 transgenic mice were infected with M. tuberculosis (H37Rv). A dose of 100 bacilli was used for infection via respiratory route. Bacterial load in lung and spleen of infected mice was determined at 2, 4, 6 and 8 wk post-infection. Gene expression analysis for Th1 cytokines and inducible nitric oxide synthase (iNOS) was performed in infected lung tissues by quantitative reverse transcription (RT)-PCR. Results: SMAR1 transgenic mice from both BALB/c and C57BL/6 genetic background displayed higher bacillary load and susceptibility to M. tuberculosis infection compared to wild type mice. This susceptibility was attributed due to compromised of Th1 response exhibited by transgenic mice. Interpretation & conclusions: SMAR1 transgenic mice exhibited susceptibility to M. tuberculosis infection in vivo irrespective of genetic background. This susceptibility was attributed to downregulation of Th1 response and its hallmark cytokine IFN-γ. Hence, SMAR1 plays an important role in modulating host immune response after M. tuberculosis infection

Dual role of Par-4 in abrogation of EMT and switching on mesenchymal to epithelial transition (MET) in metastatic pancreatic cancer cells

Epithelial-mesenchymal transition (EMT) is a critical event that occurs during the invasion and metastatic spread of cancer cells. Here, we conceive a dual mechanism of Par-4-mediated inhibition of EMT and induction of MET in metastatic pancreatic cancer cells. First, we demonstrate that 1,1′-β-D-glucopyranosyl-3,3′-bis(5-bromoindolyl)-octyl methane (NGD16), an N-glycosylated derivative of medicinally important phytochemical 3,3′-diindolylmethane (DIM) abrogates EMT by inducing pro-apoptotic protein Par-4. Induction of Par-4 (by NGD16 or ectopic overexpression) strongly impedes invasion with inhibition of major mesenchymal markers viz. Vimentin and Twist-1 epithelial marker- E-cadherin. Further, NGD16 triggers MET phenotypes in pancreatic cancer cells by augmenting ALK2/Smad4 signaling in a Par-4-dependent manner. Conversely, siRNA-mediated silencing of endogenous Par-4 unveil reversal of MET with diminished E-cadherin expression and invasive phenotypes. Additionally, we demonstrate that intact Smad4 is essential for Par-4-mediated maintenance of E-cadherin level in MET induced cells. Notably, we imply that Par-4 induction regulates E-cadherin levels in the pancreatic cancer cells via modulating Twist-1 promoter activity. Finally, in vivo studies with syngenic mouse metastatic pancreatic cancer model reveal that NGD16 strongly suppresses metastatic burden, ascites formation, and prolongs the overall survival of animals effectively