Publications by authors named "Shubhankar K Singh"

Unlabelled: This study highlights the potential neurotoxic and impaired behavioral effects associated with high fluoride concentrations in drinking water.

Purpose: Fluoride is known to cause neurotoxicity, evinced by lower I.Q.

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Unlabelled: As an ailment, leishmaniasis is still an incessant challenge in neglected tropical diseases and neglected infections of poverty worldwide. At present, the diagnosis and treatment to combat tropical infections are not substantial remedies and require advanced & specific research. Therefore, there is a need for a potential novel target to overcome established medicament modalities' limitations in pathogenicity.

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Visceral leishmaniasis (VL) is one of the most fatal and neglected tropical diseases caused by donovani (). The applications of currently available chemotherapy (amphotericin B, miltefosine, and others) in VL treatment have been limited due to their poor bioavailability, unfavorable toxicity profile, and prolonged parenteral dosing. Quercetin (QT), a potent natural antioxidant, is a prominent target when conducting investigations on alternative therapies against infections.

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Article Synopsis
  • The study aimed to compare the effectiveness of liposomal amphotericin B and miltefosine in treating post-kala-azar dermal leishmaniasis among 100 patients.
  • The initial cure rates showed a high success of both treatments, with miltefosine achieving a better final cure rate (86.9%) compared to liposomal amphotericin B (74.5%), although both had some cases of relapse.
  • Researchers concluded that miltefosine should be the first-line treatment for this condition, while liposomal amphotericin B remains a viable option for kala-azar elimination in the Indian subcontinent.
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The emergence of increased resistance to the available drugs has created a situation that demands to find out more specific molecular drug targets for Leishmaniasis. The enoyl acyl carrier protein reductase (ENR), a regulatory enzyme in type II fatty acid synthesis, was confirmed as a novel drug target and triclosan as its specific inhibitor in many microorganisms. In this study, the triclosan was tested for the leishmanicidal property against () and the results of and drug assays on promastigotes and amastigotes showed that triclosan possessed antileishmanial activity with a half minimal inhibitory concentration (IC) of 30 µM.

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Visceral leishmaniasis (VL)-related mortality and morbidity imposes a great deal of health concern across the globe. The existing anti-leishmanial drug regimen generally fails to eliminate newly emerging resistant isolates of this dreadful parasite. In such circumstances, the development of a prophylactic strategy to impart protection against the disease is likely to take center stage.

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Background: Amphotericin B (AmB) as a liposomal formulation of AmBisome is the first line of treatment for the disease, visceral leishmaniasis, caused by the parasite . However, nephrotoxicity is very common due to poor water solubility and aggregation of AmB. This study aimed to develop a water-soluble covalent conjugate of gold nanoparticle (GNP) with AmB for improved antileishmanial efficacy and reduced cytotoxicity.

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Background: Surveillance of post-kala-azar dermal leishmaniasis (PKDL) is critical to the elimination of visceral leishmaniasis (VL). In this study we assessed the feasibility of using trained field workers for detecting suspected PKDL cases.

Methods: A cross-sectional study using a multistage sampling technique was conducted in the Araria district of Bihar.

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The shift of macrophage and T-cell repertoires towards proinflammatory cytokine signalling ensures the generation of host-protective machinery that is otherwise compromised in cases of the intracellular Leishmania parasite. Different groups have attempted to restore host protective immunity. These vaccine candidates showed good responses and protective effects in murine models, but they generally failed during human trials.

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This study reports a structural and functional heterogeneity of CD8CD56NKT cells, which usually decrease quantitatively during visceral leishmaniasis. Based on fluorescence intensity of CD8 receptors on CD56NKT cells, two populations of CD8CD56NKT cells have been identified. These cells were recognized as CD8CD56NKT and CD8CD56NKT cells.

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Sterile cure from visceralized Leishmania donovani (L. donovani) needs Th1 cell support along with the assistance from innate immune cells, NK cells and NKT cells. NKT cells play as a connecting link between innate and adaptive immune cell and support T helper cell function.

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Post kala-azar dermal leishmaniasis (PKDL) is often considered to be the anthroponotic reservoir of visceral leishmaniasis (VL) in India. A better understanding of the host immune-response in dermal lesions of PKDL patients is therefore of utmost significance to minimize such patients and to restrict VL transmission. Although the innate immune response is known to play an important role in parasite clearance from dermal lesions, the actual contribution of innate cells to the pathogenicity of PKDL is poorly understood.

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We report here a Leishmania donovani ornithine decarboxylase (Ld-ODC) gene used as a DNA vaccine against visceral leishmaniasis in a murine Balb/c mouse model. This study also evaluated the possible mechanism of action directed by this candidate. We found a Th1 immune response after immunization using an Ld-ODC DNA vaccine, with results based on the rearrangement of TCR-V-α-2, proliferation of Carboxy fluorescein Succinimidyle ester positive T cells, which were able to produce cytokines such as TNF-α, IFN-γ, IL-12 and IL-2, but not IL-4, IL-5, IL-6 and IL-10, and modulations of the STAT-1 and p38 MAP kinase signaling pathways.

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Article Synopsis
  • The study investigates the effects of a specific protein (rLd-iPGAM) from Leishmania donovani on immune cells from healthy individuals and those treated for visceral leishmaniasis, highlighting its potential to modulate T-cell activity.
  • Stimulation with rLd-iPGAM resulted in increased levels of key immune substances, promoting inflammation and enhancing the body's defensive responses against the parasite, while regulating certain cytokines to balance immune activity.
  • The findings suggest that rLd-iPGAM could be a promising candidate for vaccine development due to its ability to activate and enhance immune responses, including boosting macrophage activity and lymphocyte proliferation.
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The unreliability of most of the existing antibody-based diagnostic kits to discriminate between active and treated VL cases, relapse situation and reinfection are a major hurdle in controlling the cases of Kala-azar in an endemic area. An antigen targeted diagnostic approaches can be an attractive strategy to overcome these problems. Hence, this study was focused on identifying the Leishmania antigens, lies in circulating immune complex (CICs), can be used for diagnostic as well as prognostic purposes.

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Visceral leishmaniasis (VL) is a disease that is associated with compromised immunity and drug un-responsiveness as well as with the emergence of drug resistance in Leishmania donovani (Ld). Ld down-modulates cellular immunity by manipulating signaling agents, including a higher expression of the adhesion molecule CD58. The expression of CD58 and CD2 on natural killer (NK) cells facilitates intercellular adhesion and signaling.

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Diagnosis of visceral leishmaniasis (VL) is often hindered by cross-reactions with antigens from other related parasite infections. This study aimed to develop an immunochromatographic test (ICT) which can detect the antigen present in circulating immune complexes (CICs) of VL patients using B-cell epitope-specific antibodies. MS analysis of six immunoreactive 2DE spots revealed two epitopes i.

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Protein disulphide isomerase (PDI) is one of the key enzymes essential for the survival of Leishmania donovani in the host. Our study suggested that PDI is associated with the generation of Th1-type of cellular responses in treated Visceral leishmaniasis (VL) subjects. The stimulation of Peripheral blood mononuclear cells (PBMCs) with recombinant Protein Disulphide Isomerase upregulated the reactive oxygen species generation, Nitric oxide release, IL12 and IFN-γ production indicating its pivotal role in protective immune response.

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The objective of this study was to understand the categorical function of CD4(+)CD56(+) and CD8(+)CD56(+) NKT cells in human visceral leishmaniasis. These cell populations were significantly deregulated in human peripheral blood during VL. The in vitro experiments showed that CD4(+)NKT cells, but not CD8(+)NKT cells, migrated towards the Leishmania donovani infection site.

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As phospho proteins are reported to be involved in virulence and survival, the ability of Leishmania to inhibit macrophage effector functions may result from a direct interference of leishmanial molecules with macrophage signal transduction pathways. Several such proteins such as pp63, pp41 and pp29 have also been identified as a Th1 stimulatory protein in the Leishmania donovani. In the present study, the immunogenicity of a cocktail of pp63+pp41+pp29 was assessed by estimation of serum antibody titre, nitric oxide(NO) production, estimation of Th1 cytokine(IFN-γ) as well as Th2 cytokines(IL-4), and determination of parasite load in L.

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Objective: Malnutrition may be significant in the modulation of immune responses in visceral leishmaniasis (VL). Data on the relationship between malnutrition and innate immune response in VL are limited. The aim of this study was to examine the effect of malnutrition on the profile of innate immune functions of polymorphonuclear neutrophil granulocytes (PMNs) and monocytes through comparison of well-nourished and malnourished Indian patients with VL.

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Lymphocyte function associated antigen 3 (LFA-3) is known as adhesion molecule with its role in T-cell activation signaling as well as in Foxp3 expression. Its influences on IL-10 production is also available, whose role in pathogenesis is well documented. However, this molecule is not yet directly addressed for its association with visceral leishmaniasis (VL).

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The present study explains a novel method of Leishmania promastigotes culture decontamination. The method is based on motility of Leishmania promastigotes across agar barrier which facilitates decontamination from yeast and other non motile contamination. This is inexpensive, easy, rapid and reliable physical method and is able to save valuable isolates in culture.

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The definitive diagnosis of visceral leishmaniasis (VL) requires invasive procedures for demonstration of parasites in tissue smear or culture. These procedures need expertise and laboratory supports and cannot be performed in the field. The aim of the present study was to evaluate the existing rK-39 immunochromatographic nitrocellulose strips test (ICT) with some modification in human urine for diagnosis of VL.

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