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This work was supported by a grant from CONCYTEC. We are very grateful to Holger Valqui and Oscar Moran for their critical comments, and to ClaudiaMachicado and Jose Choufor their comments and help in compiling and analysing part of the DNA sequences that support this work. Thanks also to Arman- do Bernui, Javier Espinoza, Jairzhinho Ramos, Luis Marky and Cristian Orrego, for their contribution to discussions, and especially to Mrs Ellen M. Pragen for her editorial work.
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artículo
Publicado 2019
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Chagas disease is a trypanosomiasis disease inflicted by Trypanosoma cruzi parasite. In Latin America, at least 10 million people are infected and annually, 10,000 casualties are deplored. Macrophage infectivity potentiator protein is one of the major virulence factors secreted by T. cruzi (TcMIP) in order to infect its host but little is known about its mechanism of action. Studies confer TcMIP an important role in the extracellular matrix transmigration and basal lamina penetration. Here, we report the backbone 1H, 13C, and 15N resonance assignment of TcMIP and the comparison of the secondary structure obtained against reported X-ray crystallography data.
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Publicado 2017
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The aim of this work is to design, implement and validate a primary communication system based on a brain-computer interface. There are people who-for various reasons-are affected in their ability to externalize their communication, however, they receive and process information from different sources. This system would allow basic communication-allowing the user to answer closed questions-through thought. The system was implemented by analyzing and interpreting electrical signals from brain activity, collected through electrodes attached to the scalp. The analog electrical signals were received by a data acquisition system and digitized for computer analysis. We implemented different signal processing techniques, pattern analysis, and classification and discrimination methods. By analyzing these signals and interpreting the electrical patterns, was achieved understand answers to simple q...
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This study was funded by CONCYTEC-PROCYT 245-2008 and FINCyT-EQUIP 100-2009. MZ was a grantee of Bill and Melinda Gates Foundation (OPPOPP1140557). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
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Publicado 2020
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Pyrazinamide (PZA) is considered the pivot drug in all tuberculosis treatment regimens due to its particular action on the persistent forms of Mycobacterium tuberculosis. However, no drug susceptibility test (DST) is considered sufficiently reliable for routine application. Although molecular tests are endorsed, their application is limited to known PZA resistance associated mutations. Microbiological DSTs for PZA have been restricted by technical limitations, especially the necessity for an acidic pH. Here, for the first time, MODS culture at neutral pH was evaluated using high PZA concentrations (400 and 800 _g/ml) to determine PZA susceptibility directly from sputum samples. Sputum samples were cultured with PZA for up to 21 days at 37°C. Plate reading was performed at two time points: R1 (mean, 10 days) and R2 (mean, 13 days) for each PZA concentration. A consensus reference test, c...
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Publicado 2021
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This study was funded by a grant from the National Fund for Scientific, Technological Development and Technological Innovation (FONDECYT) of the National Council of Science, Technology and Technological Innovation (CONCYTEC) of Peru, Contract N° 171-2015-FONDECYT.
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Publicado 2017
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Autism spectrum disorder (ASD) currently affects nearly 1 in 160 children worldwide. In over two-thirds of evaluations, no validated diagnostics are used and gold standard diagnostic tools are used in less than 5% of evaluations. Currently, the diagnosis of ASD requires lengthy and expensive tests, in addition to clinical confirmation. Therefore, fast, cheap, portable, and easy-to-administer screening instruments for ASD are required. Several studies have shown that children with ASD have a lower preference for social scenes compared with children without ASD. Based on this, eye-tracking and measurement of gaze preference for social scenes has been used as a screening tool for ASD. Currently available eye-tracking software requires intensive calibration, training, or holding of the head to prevent interference with gaze recognition limiting its use in children with ASD.
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artículo
Publicado 2019
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Although pyrazinamide (PZA) is a key component of first- and second-line tuberculosis treatment regimens, there is no gold standard to determine PZA resistance. Approximately 50% of multidrug-resistant tuberculosis (MDR-TB) and over 90% of extensively drug-resistant tuberculosis (XDR-TB) strains are also PZA resistant. pncA sequencing is the endorsed test to evaluate PZA susceptibility. However, molecular methods have limitations for their wide application. In this study, we standardized and evaluated a new method, MODS-Wayne, to determine PZA resistance. MODS-Wayne is based on the detection of pyrazinoic acid, the hydrolysis product of PZA, directly in the supernatant of sputum cultures by detecting a color change following the addition of 10% ferrous ammonium sulfate. Using a PZA concentration of 800 μg/ml, sensitivity and specificity were evaluated at three different periods of incub...
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Publicado 2019
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The prodrug pyrazinamide (PZA) is metabolized by the mycobacteria to pyrazinoic acid (POA), which is expelled into the extracellular environment. PZA resistance is highly associated to a lack of POA efflux. Thus, by detecting a reduction of the concentration of POA in the extracellular environment, by means of lab-on-a-chip (LoC)-SERS (surface-enhanced Raman spectroscopy), an alternative approach for the discrimination of PZA resistant mycobacteria is introduced. A droplet-based microfluidic SERS device has been employed to illustrate the potential of the LoC-SERS method for the discrimination of PZA resistant mycobacteria. The two analytes were detected discretely in aqueous solution with a limit of detection of 27 ?m for PZA and 21 ?m for POA. The simultaneous detection of PZA and POA in aqueous mixtures could be realized within a concentration range from 20 ?m to 50 ?m for PZA and fro...
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Publicado 2018
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Tuberculosis (TB) is a significant cause of morbidity and mortality worldwide. The patient compliance with the long treatment regimens is essential for successful eradication. Pyrazinamide (PZA) shortens these regimens from 9 to 6 months, and therefore, improves treatment completion rates. Although PZA is a first-line medication for the treatment of TB, no simple or reliable assay to determine PZA resistance is yet available. In the presence of PZA, only susceptible Mycobacterium tuberculosis strains release pyrazinoic acid (POA). Therefore, the measurement and quantification of released POA is an indicator of PZA resistance.
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Publicado 2013
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The initial development of the algorithm was funded by a Wellcome Trust Career Development Fellowship awarded to DAJM [078067/Z/05] and by the Peruvian FINCYT Proyecto de Interes Nacional [PIN 061] and CONCYTEC PROCYT awarded to MZ. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
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Publicado 2020
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Mycobacterium tuberculosis nicotinamidase-pyrazinamidase (PZAse) is a metalloenzyme that catalyzes conversion of nicotinamide-pyrazinamide to nicotinic acid-pyrazinoic acid. This study investigated whether a metallochaperone is required for optimal PZAse activity. M. tuberculosis and Escherichia coli PZAses (PZAse-MT and PZAse-EC, respectively) were inactivated by metal depletion (giving PZAse-MT–Apo and PZAse-EC–Apo). Reactivation with the E. coli metallochaperone ZnuA or Rv2059 (the M. tuberculosis analog) was measured. This was repeated following proteolytic and thermal treatment of ZnuA and Rv2059. The CDC1551 M. tuberculosis reference strain had the Rv2059 coding gene knocked out, and PZA susceptibility and the pyrazinoic acid (POA) efflux rate were measured. ZnuA (200 M) achieved 65% PZAse-EC–Apo reactivation. Rv2059 (1 M) and ZnuA (1 M) achieved 69% and 34.3% PZAse-MT–Apo ...
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objeto de conferencia
Pneumonia is one of the major causes of child mortality. Unfortunately, in developing countries there is a lack of infrastructure and medical experts in rural areas to provide the required diagnostics opportunely. Lung ultrasound echography has proved to be an important tool to detect lung consolidates as evidence of pneumonia.
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objeto de conferencia
Publicado 2017
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Pneumonia is one of the major causes of child mortality, but it is curable if one can achieves early diagnostics. Unfortunately, in developing countries there is a lack of infrastructure and medical experts in rural areas to provide the required diagnostics opportunely. Lung ultrasound echography has proved to be an important tool to detect lung consolidates as evidence of pneumonia. The use of ultrasound to detect pneumonia is limited by the image analysis for interpretation, which is carried by human experts. Pattern recognition and image analysis is a potential tool to facilitate recognition of pneumonia consolidates in absence of medical experts for automatic diagnostics. To perform an automatic analysis of lung ultrasound images for pneumonia detection, the noise introduced by the image portion of the skin, notably complicates the processing and interpretation. This paper presents a...
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Publicado 2018
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Pneumonia is one of the major causes of child mortality, yet with a timely diagnosis, it is usually curable with antibiotic therapy. In many developing regions, diagnosing pneumonia remains a challenge, due to shortages of medical resources. Lung ultrasound has proved to be a useful tool to detect lung consolidation as evidence of pneumonia. However, diagnosis of pneumonia by ultrasound has limitations: it is operator-dependent, and it needs to be carried out and interpreted by trained personnel. Pattern recognition and image analysis is a potential tool to enable automatic diagnosis of pneumonia consolidation without requiring an expert analyst. This paper presents a method for automatic classification of pneumonia using ultrasound imaging of the lungs and pattern recognition.
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Publicado 2018
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This work was partially supported by the Fogarty International Center/NIH (training grant numbers D43TW001140 and D43TW007393) and by the National Council for Science, Technology and Innovation of Peru (CONCYTEC).
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artículo
Publicado 2020
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The use of L protein coupled magnetic particles for the concentration and purification of immunoglobulin M (mIgM) monoclonal antibodies against Taenia solium was evaluated. Three concentration methods and different elution times were evaluated and the ratio of particles to the ratio of mIgM was optimized. It is demonstrated that: 1) with the use of magnetic particles, a previous concentration of mIgM is not required, which reduces the manipulation of the antibodies and improves the recovery, 2) the use of a binding buffer can be omitted, since the pH of most cell culture supernatants are neutral, and 3) longer elution times (~ 45 minutes) are needed to increase recovery to a level greater than 80%. The study demonstrates that the use of L protein-coupled magnetic particles is a simple and efficient tool for mIgM concentration and purification. © 2020, Instituto Nacional de Salud. All ri...
