N-acetyl cysteine enhances imatinib-induced apoptosis of Bcr-Abl+ cells by endothelial nitric oxide synthase-mediated production of nitric oxide

Introduction  Imatinib, a small-molecule inhibitor of the Bcr-Abl kinase, is a successful drug for treating chronic myeloid leukemia (CML). Bcr-Abl kinase stimulates the production of H₂O₂, which in turn activates Abl kinase. We therefore evaluated whether N-acetyl cysteine (NAC), a ROS scavenger improves imatinib efficacy. Materials and methods  Effects of imatinib and NAC either alone or in combination were assessed on Bcr-Abl⁺ cells to measure apoptosis. Role of nitric oxide (NO) in NAC-induced enhanced cytotoxicity was assessed using pharmacological inhibitors and siRNAs of nitric oxide synthase isoforms. We report that imatinib-induced apoptosis of imatinib-resistant and imatinib-sensitive Bcr-Abl⁺ CML cell lines and primary cells from CML patients is significantly enhanced by co-treatment with NAC compared to imatinib treatment alone. In contrast, another ROS scavenger glutathione reversed imatinib-mediated killing. NAC-mediated enhanced killing correlated with cleavage of caspases, PARP and up-regulation and down regulation of pro- and anti-apoptotic family of proteins, respectively. Co-treatment with NAC leads to enhanced production of nitric oxide (NO) by endothelial nitric oxide synthase (eNOS). Involvement of eNOS dependent NO in NAC-mediated enhancement of imatinib-induced cell death was confirmed by nitric oxide synthase (NOS) specific pharmacological inhibitors and siRNAs. Indeed, NO donor sodium nitroprusside (SNP) also enhanced imatinib-mediated apoptosis of Bcr-Abl⁺ cells. Conclusion  NAC enhances imatinib-induced apoptosis of Bcr-Abl⁺ cells by endothelial nitric oxide synthase-mediated production of nitric oxide.     

A framework for feature extraction from hospital medical data with applications in risk prediction

Background

Feature engineering is a time consuming component of predictive modeling. We propose a versatile platform to automatically extract features for risk prediction, based on a pre-defined and extensible entity schema. The extraction is independent of disease type or risk prediction task. We contrast auto-extracted features to baselines generated from the Elixhauser comorbidities.

Results

Hospital medical records was transformed to event sequences, to which filters were applied to extract feature sets capturing diversity in temporal scales and data types. The features were evaluated on a readmission prediction task, comparing with baseline feature sets generated from the Elixhauser comorbidities. The prediction model was through logistic regression with elastic net regularization. Predictions horizons of 1, 2, 3, 6, 12 months were considered for four diverse diseases: diabetes, COPD, mental disorders and pneumonia, with derivation and validation cohorts defined on non-overlapping data-collection periods.For unplanned readmissions, auto-extracted feature set using socio-demographic information and medical records, outperformed baselines derived from the socio-demographic information and Elixhauser comorbidities, over 20 settings (5 prediction horizons over 4 diseases). In particular over 30-day prediction, the AUCs are: COPD—baseline: 0.60 (95% CI: 0.57, 0.63), auto-extracted: 0.67 (0.64, 0.70); diabetes—baseline: 0.60 (0.58, 0.63), auto-extracted: 0.67 (0.64, 0.69); mental disorders—baseline: 0.57 (0.54, 0.60), auto-extracted: 0.69 (0.64,0.70); pneumonia—baseline: 0.61 (0.59, 0.63), auto-extracted: 0.70 (0.67, 0.72).

Conclusions

The advantages of auto-extracted standard features from complex medical records, in a disease and task agnostic manner were demonstrated. Auto-extracted features have good predictive power over multiple time horizons. Such feature sets have potential to form the foundation of complex automated analytic tasks.

Electronic supplementary material

The online version of this article (doi:10.1186/s12859-014-0425-8) contains supplementary material, which is available to authorized users.     

Synthesis, X-ray crystal structure and magnetic study of the 1D {[Cu2(N,N,N′,N′-tetramethyl-ethylenediamine)2(μ-1,5-dca)2(dca)2]}n complex

Reaction of Cu(NO₃)₂ · 3H₂O, N,N,N′,N′-tetramethyl-ethylenediamine (L) and sodium dicyanamide (Nadca) in aqueous medium yields a complex the {[Cu₂L₂(μ-1,5-dca)₂(dca)₂]}_n complex, 1. Single crystal X-ray analysis reveals that complex 1 has a 1D infinite chain structure in which copper(II) ions are bridged by single dicyanamide anions in an end-to-end fashion. The coordination environment around copper(II) is distorted square pyramidal. Two among the four coordination sites of the basal plane are occupied by the nitrogen atoms of the diamine and two remaining sites are occupied by the terminal nitrogen atom of a bridging and of a monodentate dca anions. The fifth coordination site (apical) is occupied by a nitrogen atom from a bridging dca anion of an adjacent CuL(dca)₂ moiety, yielding the [Cu₂L₂(μ-1,5-dca)₂(dca)₂] dinuclear unit. Dimeric units are connected to each other by single μ-1,5-dicyanamido group to form infinite 1D chains which propagate parallel to the crystallographic c-axis. The variable temperature magnetic susceptibility measurements evidenced weakly antiferromagnetic interactions (J = −0.26 cm⁻¹) in {[Cu₂L₂(μ-1,5-dca)₂(dca)₂]}_n, 1.     

Can Currently Available Advanced Combustion Biomass Cook-Stoves Provide Health Relevant Exposure Reductions? Results from Initial Assessment of Select Commercial Models in India

EcoHealth - Household air pollution from use of solid fuels is a major contributor to the national burden of disease in India. Currently available models of advanced combustion biomass cook-stoves...     

Cellular therapy by allogeneic macrophages against visceral leishmaniasis: Role of TNF-α

Tumor necrosis factor α (TNF-α) is an essential player in infection with Leishmania, controlling inflammatory lesion and parasite killing. We recently have shown the leishmanicidal activity of transmembrane form of TNF (mTNF) derived from allogeneic natural killer (NK) cells in experimental visceral leishmaniasis. Allogeneic macrophages and human monocytes derived mTNF has significantly higher antileishmanial activity compared to allogeneic NK cells. Unlike NK cells, syngeneic macrophages also possess antileishmanial activity, although degree of activity is significantly less compared to allogeneic macrophages. Cellular therapy by intravenous transfer of allogeneic macrophages enhances leishmanicidal effect against the established infection in susceptible animal by reducing the splenic parasite burden to 28.3 ± 4.71 × 10⁵ compared to 256.00 ± 17.36 × 10⁵ in control group. In vivo treatment with anti-mouse TNF-α reduces the therapeutic efficacy of the allogeneic macrophages by increasing the parasite load in spleen of infected mice. These results demonstrated that allogeneic and xenogeneic macrophages induce cytokine mediated protective mechanism against infected macrophages via TNF-α in vitro and, possibly in vivo. The macrophage mediated protective role in absence of T cell help demonstrate an unique property of the mononuclear phagocytes in controlling infection and inflammation in visceral leishmaniasis, despite being acts as a host cell for the same parasite.     

Dihydrobetulinic acid induces apoptosis in Leishmania donovani by targeting DNA topoisomerase I and II: implications in antileishmanial therapy

Leishmaniasis is the second-most dreaded parasitic disease in the modern world, behind malaria. The lack of effective vaccines demand improved chemotherapy along with the development of lead compounds and newer targets. We report here that the pentacyclic triterpenoid, dihydrobetulinic acid (DHBA), is a novel lead compound for antileishmanial therapy. It acts by targeting DNA topoisomerases. DNA topoisomerase I and II activity was studied using relaxation and decatenation assays. Mechanistic studies were based on the decreased mobility of enzyme-bound DNA compared with free DNA and the differential mobility of nicked and supercoiled monomers in 1% agarose gel. Pulsed field gradient gel electrophoresis, confocal microscopy, and transmission electron microscopy were performed to assess cytotoxicity of the compound and ultrastructural damage of the parasite. Apoptosis was studied by the isolation of DNA from DHBA-treated parasites and subsequent electrophoresis in 1% agarose gel. DHBA inhibits growth of Leishmania donovani promastigotes and amastigotes with an IC50 of 2.6 and 4.1 microM respectively. The compound is a dual inhibitor of DNA topoisomerases that fails to induce DNA cleavage and acts by preventing the formation of enzyme-DNA binary complex, ultimately inducing apoptosis. Treatment of infected golden hamsters with the compound markedly reduces (> 92%) parasitic burden, both in spleen and liver. Interestingly, the 17-decarboxylated analogue, dihydrolupeol, does not inhibit DNA topoisomerase I and II, has no effect on parasitic growth, and also fails to induce apoptosis. DHBA is a potent antileishmanial agent that induces apoptosis by primarily targeting DNA topoisomerases. Therefore it is a strong candidate for use in designing new antileishmanial drugs.     

Dendritic cell-based immunotherapy combined with antimony-based chemotherapy cures established murine visceral leishmaniasis

Dendritic cells (DCs) have been proposed to play a critical role as adjuvants in vaccination and immunotherapy. In this study we evaluated the combined effect of soluble Leishmania donovani Ag (SLDA)-pulsed syngeneic bone marrow-derived DC-based immunotherapy and antimony-based chemotherapy for the treatment of established murine visceral leishmaniasis. Three weekly injections of SLDA-pulsed DCs into L. donovani-infected mice reduced liver and splenic parasite burden significantly, but could not clear parasite load from these organs completely. Strikingly, the conventional antileishmanial chemotherapy (sodium antimony gluconate) along with injections of SLDA-pulsed DCs resulted in complete clearance of parasites from both these organs. Repetitive in vitro stimulation of splenocytes from uninfected or L. donovani-infected mice with SLDA-pulsed DCs led to the emergence of CD4(+) T cells with characteristics of Th1 cells. Our data indicate that DC-based immunotherapy enhances the in vivo antileishmanial potential of antimony or vice versa.     

Cadmium bioaccumulation in Lamellidens marginalis and human health risk assessment: A case study in India

Abstract

Lamellidens marginalis is an easily available food with high nutritive value. The present study is based on the East Kolkata Wetlands (EKW), India that produces mussels, consumed by human. Thus, the study of heavy metal pollution in the wastewater and mussel, and its transport to human is considered to be need of the hour to assess the health risk to human. The present study focuses on the cadmium accumulation in the outer exposed organs and the internal organs of L. marginalis. The mussel, sediment, and water were collected from the field and analyzed in the laboratory. The environmental factors were analyzed in situ. The survey work was conducted among the consumers of mussel around the EKW to predict the effect of cadmium on human. The result showed that the cadmium concentration of water was relatively important for the bioaccumulation process in L. marginalis. People having low level of income and age above forty, living adjoining the EKW were at high risk of cadmium pollution. The hazard quotient value of the above group was highest among all the groups across age and income. A ‘biofilter’ technique was suggested to mitigate the biomagnification of cadmium at the EKW.     

Antitumor activity with nontoxic doses of protein A

Summary This report confirms our previous observation that IV inoculation of purified protein A causes regression of rat mammary adenocarcinomas. In treated tumors, we have obtained histological evidence of changes indicating tumor cell destruction. Protein A treatment does not cause reduction in the body weight or organ weights of rats; nor does it cause any decrease in activity of the enzymes of the microsomal mixed function oxidase system in the liver. Protein A stimulates peripheral white cell counts in normal rats, but not in tumor-bearing rats. We found that protein A infusion reduced (P<0.0005) the level of circulating plasma immune complex concentration. A homing study with ¹²⁵I-labeled protein A indicated that liver, spleen, and kidney tissues are the major sites of protein A accumulation. Therefore, protein A seemed to exert its antitumor effects without causing any generalized toxicity to the system. It is postulated that the action of protein A may be related to its ability to cause a drastic reduction in circulating plasma immune complex concentration, thus potentiating the immune reactivity of the host observed earlier.