40 research outputs found
Study the usefulness of cartridge based NUCLEIC acid amplification test in bronchoalveolar lavage samples in the diagnosis of smear-negative/non sputum producing patients with suspected tuberculosis
Background: The aim of study is to evaluate the diagnostic value of the CBNAAT in BAL samples of smear negative for AFB or who could not produce an expectorated sputum sample.Methods: A prospective and observational study of in patient and out patient department in Department of Pulmonary Medicine of Chalmeda Anand Rao Institute of Medical Sciences, Karimnagar during the period November 2017 to November 2018.Results: Bronchoalveolar lavage cartridge based nucleic acid amplification test in bronchoalveolar lavage was done for 60 samples of patients who were having history and chest x-ray suggestive of pulmonary tuberculosis with sputum AFB negative. Out of these sputum negative samples 25 were BAL CBNAAT positive and rest were negative.Conclusions: CBNAAT adds significantly to the diagnostic yield of PTB in comparison to sputum smear microscopy. It has additional advantage of identifying rifampicin resistance with high sensitivity and specificity
A novel Plasmodium falciparum rhoptry associated adhesin mediates erythrocyte invasion through the sialic-acid dependent pathway
Erythrocyte invasion by Plasmodium falciparum merozoites is
central to blood-stage infection and malaria pathogenesis. This
intricate process is coordinated by multiple parasite adhesins
that bind erythrocyte receptors and mediate invasion through
several alternate pathways. P. falciparum expresses 2700 genes
during the blood-stages, of which the identity and function of
many remains unknown. Here, we have identified and characterized
a novel P. falciparum rhoptry associated adhesin (PfRA) that
mediates erythrocyte invasion through the sialic-acid dependent
pathway. PfRA appears to play a significant functional role as
it is conserved across different Plasmodium species. It is
localized in the rhoptries and further translocated to the
merozoite surface. Both native and recombinant PfRA specifically
bound erythrocytes in a sialic-acid dependent, chymotrypsin and
trypsin resistant manner, which was abrogated by PfRA antibodies
confirming a role in erythrocyte invasion. PfRA antibodies
inhibited erythrocyte invasion and in combination with
antibodies against other parasite ligands produced an additive
inhibitory effect, thus validating its important role in
erythrocyte invasion. We have thus identified a novel P.
falciparum adhesin that binds with a sialic acid containing
erythrocyte receptor. Our observations substantiate the strategy
to block P. falciparum erythrocyte invasion by simultaneously
targeting multiple conserved merozoite antigens involved in
alternate invasion pathways
Identifying Immune Correlates of Protection Against Plasmodium falciparum Through a Novel Approach to Account for Heterogeneity in Malaria Exposure
Background: A main criterion to identify malaria vaccine
candidates is the proof that acquired immunity against them is
associated with protection from disease. The age of the studied
individuals, heterogeneous malaria exposure, and assumption of
the maintenance of a baseline immune response can confound these
associations. Methods: Immunoglobulin G/immunoglobulin M (IgG/
IgM) levels were measured by Luminex(R) in Mozambican children
monitored for clinical malaria from birth until 3 years of age,
together with functional antibodies. Studied candidates were
pre-erythrocytic and erythrocytic antigens, including
EBAs/PfRhs, MSPs, DBLs, and novel antigens merely or not
previously studied in malaria-exposed populations. Cox
regression models were estimated at 9 and 24 months of age,
accounting for heterogeneous malaria exposure or limiting
follow-up according to the antibody's decay. Results:
Associations of antibody responses with higher clinical malaria
risk were avoided when accounting for heterogeneous malaria
exposure or when limiting the follow-up time in the analyses.
Associations with reduced risk of clinical malaria were found
only at 24 months old, but not younger children, for IgG breadth
and levels of IgG targeting EBA140III-V, CyRPA, DBL5epsilon and
DBL3x, together with C1q-fixation activity by antibodies
targeting MSP119. Conclusions: Malaria protection correlates
were identified, only in children aged 24 months old when
accounting for heterogeneous malaria exposure. These results
highlight the relevance of considering age and malaria exposure,
as well as the importance of not assuming the maintenance of a
baseline immune response throughout the follow-up. Results may
be misleading if these factors are not considered
Plasmodium falciparum Reticulocyte Binding-Like Homologue Protein 2 (PfRH2) Is a Key Adhesive Molecule Involved in Erythrocyte Invasion
Erythrocyte invasion by Plasmodium merozoites is a complex, multistep process that is mediated by a number of parasite ligand-erythrocyte receptor interactions. One such family of parasite ligands includes the P. falciparum reticulocyte binding homologue (PfRH) proteins that are homologous with the P. vivax reticulocyte binding proteins and have been shown to play a role in erythrocyte invasion. There are five functional PfRH proteins of which only PfRH2a/2b have not yet been demonstrated to bind erythrocytes. In this study, we demonstrated that native PfRH2a/2b is processed near the N-terminus yielding fragments of 220 kDa and 80 kDa that exhibit differential erythrocyte binding specificities. The erythrocyte binding specificity of the 220 kDa processed fragment of native PfRH2a/2b was sialic acid-independent, trypsin resistant and chymotrypsin sensitive. This specific binding phenotype is consistent with previous studies that disrupted the PfRH2a/2b genes and demonstrated that PfRH2b is involved in a sialic acid independent, trypsin resistant, chymotrypsin sensitive invasion pathway. Interestingly, we found that the smaller 80 kDa PfRH2a/2b fragment is processed from the larger 220 kDa fragment and binds erythrocytes in a sialic acid dependent, trypsin resistant and chymotrypsin sensitive manner. Thus, the two processed fragments of PfRH2a/2b differed with respect to their dependence on sialic acids for erythrocyte binding. Further, we mapped the erythrocyte binding domain of PfRH2a/2b to a conserved 40 kDa N-terminal region (rPfRH240) in the ectodomain that is common to both PfRH2a and PfRH2b. We demonstrated that recombinant rPfRH240 bound human erythrocytes with the same specificity as the native 220 kDa processed protein. Moreover, antibodies generated against rPfRH240 blocked erythrocyte invasion by P. falciparum through a sialic acid independent pathway. PfRH2a/2b thus plays a key role in erythrocyte invasion and its conserved receptor-binding domain deserves attention as a promising candidate for inclusion in a blood-stage malaria vaccine
Fostering the unleashing potential of nanocarriers-mediated delivery of ocular therapeutics
Ocular delivery is the most challenging aspect in the field of pharmaceutical research. The major hurdle for the controlled delivery of drugs to the eye includes the physiological static barriers such as the complex layers of the cornea, sclera and retina which restrict the drug from permeating into the anterior and posterior segments of the eye. Recent years have witnessed inventions in the field of conventional and nanocarrier drug delivery which have shown considerable enhancement in delivering small to large molecules across the eye. The dynamic challenges associated with conventional systems include limited drug contact time and inadequate ocular bioavailability resulting from solution drainage, tear turnover, and dilution or lacrimation. To this end, various bioactive-based nanosized carriers including liposomes, ethosomes, niosomes, dendrimer, nanogel, nanofibers, contact lenses, nanoprobes, selenium nanobells, nanosponge, polymeric micelles, silver nanoparticles, and gold nanoparticles among others have been developed to circumvent the limitations associated with the conventional dosage forms. These nanocarriers have been shown to achieve enhanced drug permeation or retention and prolong drug release in the ocular tissue due to their better tissue adherence. The surface charge and the size of nanocarriers (10–1000 nm) are the important key factors to overcome ocular barriers. Various nanocarriers have been shown to deliver active therapeutic molecules including timolol maleate, ampicillin, natamycin, voriconazole, cyclosporine A, dexamethasone, moxifloxacin, and fluconazole among others for the treatment of anterior and posterior eye diseases. Taken together, in a nutshell, this extensive review provides a comprehensive perspective on the numerous facets of ocular drug delivery with a special focus on bioactive nanocarrier-based approaches, including the difficulties and constraints involved in the fabrication of nanocarriers. This also provides the detailed invention, applications, biodistribution and safety-toxicity of nanocarriers-based therapeutcis for the ophthalmic delivery.</p
Comparative Analysis of Host Metabolic Alterations in Murine Malaria Models with Uncomplicated or Severe Malaria
Malaria
varies in severity, with complications ranging from uncomplicated
to severe malaria. Severe malaria could be attributed to peripheral
hyperparasitemia or cerebral malaria. The metabolic interactions between
the host and Plasmodium species are yet to be understood
during these infections of varied pathology and severity. An untargeted
metabolomics approach utilizing the liquid chromatography–mass
spectrometry platform has been used to identify the affected host
metabolic pathways and associated metabolites in the serum of murine
malaria models with uncomplicated malaria, hyperparasitemia, and experimental
cerebral malaria. We report that mice with malaria share similar metabolic
attributes like higher levels of bile acids, bile pigments, and steroid
hormones that have been reported for human malaria infections. Moreover,
in severe malaria, upregulated levels of metabolites like phenylalanine,
histidine, valine, pipecolate, ornithine, and pantothenate, with decreased
levels of arginine and hippurate, were observed. Metabolites of sphingolipid
metabolism were upregulated in experimental cerebral malaria. Higher
levels of 20-hydroxy-leukotriene B4 and epoxyoctadecamonoenoic
acids were found in uncomplicated malaria, with lower levels observed
for experimental cerebral malaria. Our study provides insights into
host biology during different pathological stages of malaria disease
and would be useful for the selection of animal models for evaluating
diagnostic and therapeutic interventions against malaria. The raw
data files are available via MetaboLights with the identifier MTBLS4387
Evidence for the Nucleo-Apical Shuttling of a Beta-Catenin Like Plasmodium falciparum Armadillo Repeat Containing Protein.
Eukaryotic Armadillo (ARM) repeat proteins are multifaceted with prominent roles in cell-cell adhesion, cytoskeletal regulation and intracellular signaling among many others. One such ARM repeat containing protein, ARM Repeats Only (ARO), has recently been demonstrated in both Toxoplasma (TgARO) and Plasmodium (PfARO) parasites to be targeted to the rhoptries during the late asexual stages. TgARO has been implicated to play an important role in rhoptry positioning i.e. directing the rhoptry towards the apical end of the parasite. Here, we report for the first time that PfARO exhibits a DNA binding property and a dynamic sub-cellular localization between the nucleus (early schizont) and rhoptry (late schizont) during the different stages of the asexual blood-stage life cycle. PfARO possesses a putative nuclear export signal (NES) and the nucleo-apical shuttling was sensitive to Leptomycin B (LMB) suggesting that the nuclear export was mediated by CRM1. Importantly, PfARO specifically bound an A-T rich DNA sequence of the P. falciparum Gyrase A (PfgyrA) gene, suggesting that the DNA binding specificity of PfARO is likely due to the AT-richness of the probe. This is a novel functional characteristic that has not been reported previously for any P. falciparum ARM containing protein and suggests a putative role for PfARO in gene regulation. This study describes for the first time a conserved P. falciparum ARM repeat protein with a high degree of functional versatility
Comparative Analysis of Host Metabolic Alterations in Murine Malaria Models with Uncomplicated or Severe Malaria
Malaria
varies in severity, with complications ranging from uncomplicated
to severe malaria. Severe malaria could be attributed to peripheral
hyperparasitemia or cerebral malaria. The metabolic interactions between
the host and Plasmodium species are yet to be understood
during these infections of varied pathology and severity. An untargeted
metabolomics approach utilizing the liquid chromatography–mass
spectrometry platform has been used to identify the affected host
metabolic pathways and associated metabolites in the serum of murine
malaria models with uncomplicated malaria, hyperparasitemia, and experimental
cerebral malaria. We report that mice with malaria share similar metabolic
attributes like higher levels of bile acids, bile pigments, and steroid
hormones that have been reported for human malaria infections. Moreover,
in severe malaria, upregulated levels of metabolites like phenylalanine,
histidine, valine, pipecolate, ornithine, and pantothenate, with decreased
levels of arginine and hippurate, were observed. Metabolites of sphingolipid
metabolism were upregulated in experimental cerebral malaria. Higher
levels of 20-hydroxy-leukotriene B4 and epoxyoctadecamonoenoic
acids were found in uncomplicated malaria, with lower levels observed
for experimental cerebral malaria. Our study provides insights into
host biology during different pathological stages of malaria disease
and would be useful for the selection of animal models for evaluating
diagnostic and therapeutic interventions against malaria. The raw
data files are available via MetaboLights with the identifier MTBLS4387