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Challenges in the Development of an Immunochromatographic Interferon-Gamma Test for Diagnosis of Pleural Tuberculosis
Claudia M. Denkinger, Yatiraj Kalantri, Samuel G. Schumacher, Joy S. Michael, Deepa Shankar, Arvind Saxena, Natarajan Sriram, Thangakunam Balamugesh, Robert Luo, Nira R. Pollock, Madhukar Pai, Devasahayam J. Christopher
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0085447
Abstract: Existing diagnostic tests for pleural tuberculosis (TB) have inadequate accuracy and/or turnaround time. Interferon-gamma (IFNg) has been identified in many studies as a biomarker for pleural TB. Our objective was to develop a lateral flow, immunochromatographic test (ICT) based on this biomarker and to evaluate the test in a clinical cohort. Because IFNg is commonly present in non-TB pleural effusions in low amounts, a diagnostic IFNg-threshold was first defined with an enzyme-linked immunosorbent assay (ELISA) for IFNg in samples from 38 patients with a confirmed clinical diagnosis (cut-off of 300pg/ml; 94% sensitivity and 93% specificity). The ICT was then designed; however, its achievable limit of detection (5000pg/ml) was over 10-fold higher than that of the ELISA. After several iterations in development, the prototype ICT assay for IFNg had a sensitivity of 69% (95% confidence interval (CI): 50-83) and a specificity of 94% (95% CI: 81-99%) compared to ELISA on frozen samples. Evaluation of the prototype in a prospective clinical cohort (72 patients) on fresh pleural fluid samples, in comparison to a composite reference standard (including histopathological and microbiologic test results), showed that the prototype had 65% sensitivity (95% CI: 44-83) and 89% specificity (95% CI: 74-97). Discordant results were observed in 15% of samples if testing was repeated after one freezing and thawing step. Inter-rater variability was limited (3%; 1out of 32). In conclusion, despite an iterative development and optimization process, the performance of the IFNg ICT remained lower than what could be expected from the published literature on IFNg as a biomarker in pleural fluid. Further improvements in the limit of detection of an ICT for IFNg, and possibly combination of IFNg with other biomarkers such as adenosine deaminase, are necessary for such a test to be of value in the evaluation of pleural tuberculosis.
MediaFLO - The Ultimate Mobile Broadcast Experience
Kalantri Sachin
IETE Technical Review , 2008,
Abstract: The exponential growth in wireless penetration and advancement in technology has accelerated the development of new and exciting wireless services. Given the mass appeal for video and multimedia content, technology providers have debated the feasibility and economical viability of large scale delivery of high-quality multimedia content to a wide range of wireless subscribers. Although delivery of this type of content is technically feasible over today′s existing unicast networks such as 3G, these networks cannot support the volume and type of traffic required for a fully realized multimedia delivery service (many channels delivered on a mass market scale). Offloading multicast (one-to-many) multimedia traffic to a dedicated broadcast network is more efficient and less costly than deploying similar services over 3G networks. Multicast services, such as the FLO mobile broadcast platform, are built ground up to address the market demand for mobile media and provide the critical link between technical feasibility and economic viability. Designed to work in concert with existing cellular data networks, FLO effectively addresses the issues in delivering multimedia content to a mass consumer audience. Unencumbered by legacy terrestrial or satellite delivery formats, this technology offers better performance for mobility and spectral efficiency than other mobile broadcast technologies, offering twice the channel capacity. FLO is a globally-recognized, open technology standard with a broad-based licensing program. The FLO Forum, with 90+ active members, including Huawei, LG Electronics, Motorola, Samsung and Sony Sharp, is driving the global standardization of MediaFLO Technology.
Bacteriophage-based Tests for Tuberculosis
Pai M,Kalantri S
Indian Journal of Medical Microbiology , 2005,
Accuracy and Reliability of Pallor for Detecting Anaemia: A Hospital-Based Diagnostic Accuracy Study
Ashwini Kalantri,Mandar Karambelkar,Rajnish Joshi,Shriprakash Kalantri,Ulhas Jajoo
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0008545
Abstract: Anaemia is a common disorder. Most health providers in resource poor settings rely on physical signs to diagnose anaemia. We aimed to determine the diagnostic accuracy of pallor for anaemia by using haemoglobin as the reference standard.
Factor Analysis of Paddy-Field Consolidation: Case Study of Iran
Ebrahimi Mohammad Sadegh,Kalantri Khalil,Asadi Ali
Sustainable Agriculture Research , 2012, DOI: 10.5539/sar.v1n2p108
Abstract: Land consolidation is a strategy for the development of Iranian rice-growing regions. The most important targets of the program are reducing rice farmers' expenses and increasing their income. The object of this article is to conduct a factor analysis of Iranian paddy-field consolidation. The research was conducted in the form of a survey study. The data was collected from188 farmers participating in a farm-development program in Guilan province, sampled using a stratified random sampling method. The reliability of the questionnaire was calculated using a Cronbach alpha coefficient (alpha >0.78) for different sections after conducting a pilot study. Factor analysis for farmers with rice fields in projects showed that five factors explained 63.92% of total variance. These factors were: 1) social, 2) instructional, 3) environmental, 4) economic and 5) institutional effects. Social effects alone, the factor with the greatest effect, explained 34.84% of total variance.
A commercial line probe assay for the rapid detection of rifampicin resistance in Mycobacterium tuberculosis: a systematic review and meta-analysis
Maureen Morgan, Shriprakash Kalantri, Laura Flores, Madhukar Pai
BMC Infectious Diseases , 2005, DOI: 10.1186/1471-2334-5-62
Abstract: We did a systematic review and meta-analysis to evaluate the accuracy of LiPA for the detection of rifampicin-resistant tuberculosis among culture isolates and clinical specimens. We searched Medline, Embase, Web of Science, BIOSIS, and Google Scholar, and contacted authors, experts and the manufacturer. Fifteen studies met our inclusion criteria. Of these, 11 studies used culture isolates, one used clinical specimens, and three used both. We used a summary receiver operating characteristic (SROC) curve and Q* index to perform meta-analysis and summarize diagnostic accuracy.Twelve of 14 studies that applied LiPA to isolates had sensitivity greater than 95%, and 12 of 14 had specificity of 100%. The four studies that applied LiPA directly to clinical specimens had 100% specificity, and sensitivity that ranged between 80% and 100%. The SROC curve had an area of 0.99 and Q* of 0.97.LiPA is a highly sensitive and specific test for the detection of rifampicin resistance in culture isolates. The test appears to have relatively lower sensitivity when used directly on clinical specimens. More evidence is needed before LiPA can be used to detect MDR-TB among populations at risk in clinical practice.Tuberculosis (TB) continues to be a major public health problem, particularly in developing countries. The WHO estimates that one third of the world's population is infected with Mycobacterium tuberculosis, the causative agent of TB. There were an estimated 8.3 million new active cases and 1.8 million deaths from TB in the year 2000, making it the second greatest killer among infectious diseases worldwide [1].The prevalence of multidrug-resistant TB (MDR-TB), defined as resistance to at least rifampicin (RIF) and isoniazid (INH), is rising in a number of geographic regions. According to a recent WHO report [1], the median prevalence of MDR-TB is 1% (range 0%–14.1%) among new cases and 9.3% (range 0%–48%) among previously treated cases. Rapid identification is essential for effecti
Bacteriophage- based tests for the detection of Mycobacterium tuberculosis in clinical specimens: a systematic review and meta- analysis
Shriprakash Kalantri, Madhukar Pai, Lisa Pascopella, Lee Riley, Arthur Reingold
BMC Infectious Diseases , 2005, DOI: 10.1186/1471-2334-5-59
Abstract: We did a systematic review and meta-analysis of published studies to evaluate the accuracy of phage-based tests for the direct detection of M. tuberculosis in clinical specimens. To identify studies, we searched Medline, EMBASE, Web of science and BIOSIS, and contacted authors, experts and test manufacturers. Thirteen studies, all based on phage amplification method, met our inclusion criteria. Overall accuracy was evaluated using forest plots, summary receiver operating (SROC) curves, and subgroup analyses.The data suggest that phage-based assays have high specificity (range 0.83 to 1.00), but modest and variable sensitivity (range 0.21 to 0.88). The sensitivity ranged between 0.29 and 0.87 among smear-positive, and 0.13 to 0.78 among smear-negative specimens. The specificity ranged between 0.60 and 0.88 among smear-positive and 0.89 to 0.99 among smear-negative specimens. SROC analyses suggest that overall accuracy of phage-based assays is slightly higher than smear microscopy in direct head-to-head comparisons.Phage-based assays have high specificity but lower and variable sensitivity. Their performance characteristics are similar to sputum microscopy. Phage assays cannot replace conventional diagnostic tests such as microscopy and culture at this time. Further research is required to identify methods that can enhance the sensitivity of phage-based assays without compromising the high specificity.Tuberculosis (TB) is a leading cause of morbidity and mortality worldwide. According to the World Health Organization, about one-third of the world's population is infected with Mycobacterium tuberculosis, and about 8 million new cases of TB occur each year. Despite this large burden and intensive control efforts, only about 46% of the new infectious TB cases are detected each year [1].Conventional TB diagnostics include sputum microscopy and culture of M. tuberculosis. Although microscopy is simple, specific and rapid, it suffers from low sensitivity (30–70%) [2]. Micro
Elisa kit evaluation for IGG and IGM antibodies to A-60 tubercular protein antigen
Kalantri Y,Hemvani N,Bhatia G,Chitnis D
Indian Journal of Medical Sciences , 2005,
Abstract: AIMS: The purpose of this study is to evaluate the A-60 antigen-based enzyme-linked immuno sorbent assay (ELISA) test for its sensitivity, specificity, and other related statistical parameters. SETTINGS AND DESIGN: Sera from 114 healthy volunteers, 105 bacteriologically confirmed cases of pulmonary tuberculosis (PTB), 59 sera from family contacts of PTB, and 40 sera from cases of lung infections other than tuberculosis collected from September to December 2003 were used for the kit evaluation. METHODS AND MATERIALS: Enzyme-linked immuno sorbent assay test using tuberculosis A-60 antigen-based kit manufactured by Anda Biologicals, France was used for the evaluation. STATISTICAL ANALYSIS: Differences in the optical density (OD) values for immunoglobulins G (IgG), and immunoglobulins M (IgM) antibodies in various groups were studied using t-test. RESULTS: On the basis of the findings the threshold value was setup as 400 U for IgG and mean OD for sera from healthy volunteers +2SD as the threshold for IgM. The sensitivity was 80% and specificity 95.8% for the IgG antibody test. The efficiency and predictive values were also high. The sensitivity for IgM was low (28.5%) but the specificity was high (95.7%). None of the 40 nontubercular lung infection cases were positive for the IgG and IgM antibody test for A-60, whereas five and three cases of 59 family contacts of PTB were positive for IgG and IgM antibody test. The test reproducibility was good for both IgG and IgM. CONCLUSION: IgG antibody test using A-60 antigen has good sensitivity and specificity, whereas IgM antibody test had high specificity but low sensitivity. Multicentric trials suggested evaluation of the diagnostic utility of the test for the extra-PTB.
Prevalence of Abnormal Radiological Findings in Health Care Workers with Latent Tuberculosis Infection and Correlations with T Cell Immune Response
Rajnish Joshi, Samir Patil, Shriprakash Kalantri, Kevin Schwartzman, Dick Menzies, Madhukar Pai
PLOS ONE , 2007, DOI: 10.1371/journal.pone.0000805
Abstract: Background More than half of all health care workers (HCWs) in high TB-incidence, low and middle income countries are latently infected with tuberculosis (TB). We determined radiological lesions in a cohort of HCWs with latent TB infection (LTBI) in India, and determined their association with demographic, occupational and T-cell immune response variables. Methodology We obtained chest radiographs of HCWs who had undergone tuberculin skin test (TST) and QuantiFERON-TB Gold In Tube (QFT), an interferon-γ release assay, in a previous cross-sectional study, and were diagnosed to have LTBI because they were positive by either TST or QFT, but had no evidence of clinical disease. Two observers independently interpreted these radiographs using a standardized data form and any discordance between them resolved by a third observer. The radiological diagnostic categories (normal, suggestive of inactive TB, and suggestive of active TB) were compared with results of TST, QFT assay, demographic, and occupational covariates. Results A total of 330 HCWs with positive TST or QFT underwent standard chest radiography. Of these 330, 113 radiographs (34.2%) were finally classified as normal, 206 (62.4%) had lesions suggestive of inactive TB, and 11 (3.4%) had features suggestive of active TB. The mean TST indurations and interferon-γ levels in the HCWs in these three categories were not significantly different. None of the demographic or occupational covariates was associated with prevalence of inactive TB lesions on chest radiography. Conclusion/Significance In a high TB incidence setting, nearly two-thirds of HCWs with latent TB infection had abnormal radiographic findings, and these findings had no clear correlation with T cell immune responses. Further studies are needed to verify these findings and to identify the causes and prognosis of radiologic abnormalities in health care workers.
Persistently elevated T cell interferon-γ responses after treatment for latent tuberculosis infection among health care workers in India: a preliminary report
Madhukar Pai, Rajnish Joshi, Sandeep Dogra, Deepak K Mendiratta, Pratibha Narang, Keertan Dheda, Shriprakash Kalantri
Journal of Occupational Medicine and Toxicology , 2006, DOI: 10.1186/1745-6673-1-7
Abstract: In 2004, we established a cohort of HCWs who underwent tuberculin skin testing (TST) and a whole-blood IGRA (QuantiFERON-TB-Gold In-Tube [QFT-G], Cellestis Ltd, Victoria, Australia) at a rural hospital in India. HCWs positive by either test were offered 6 months of isoniazid (INH) preventive therapy. Among the HCWs who underwent therapy, we prospectively followed-up 10 nursing students who were positive by both tests at baseline. The QFT-G assay was repeated 4 and 10 months after INH treatment completion (i.e. approximately 12 months and 18 months after the initial testing). IFN-γ responses to ESAT-6, CFP-10 and TB7.7 peptides were measured using ELISA, and IFN-γ ≥0.35 IU/mL was used to define a positive QFT-G test result.All participants (N = 10) reported direct contact with smear-positive TB patients at baseline, during and after LTBI treatment. All participants except one started treatment with high baseline IFN-γ responses (median 10.0 IU/mL). The second QFT-G was positive in 9 of 10 participants, but IFN-γ responses had declined (median 5.0 IU/mL); however, this difference was not significant (P = 0.10). The third QFT-G assay continued to be positive in 9 of 10 participants, with persistently elevated IFN-γ responses (median 7.9 IU/mL; P = 0.32 for difference against baseline average).In an environment with ongoing, intensive nosocomial exposure, HCWs had strong IFN-γ responses at baseline, and continued to have persistently elevated responses, despite LTBI treatment. It is plausible that persistence of infection and/or re-infection might account for this phenomenon. Our preliminary findings need confirmation in larger studies in high transmission settings. Specifically, research is needed to study T cell kinetics during LTBI treatment, and determine the effect of recurrent exposures on host cellular immune responses.The World Health Organization (WHO) has estimated that approximately one third of the world's population is infected with Mycobacterium tuberculos
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