The Double Burden of COVID-19 and Dengue in Nepal: The challenges ahead.

Coronavirus disease 2019 (COVID-19) pandemic has caused significant impact on the health care system. As a consequence, diagnosis and treatment of vector borne diseases including dengue has been equally affected. Nepal is no exception to this, where COVID-19 cases is exponentially increased and all resources are concentrated on its prevention, control and management. Dengue, one of the major vector-borne diseases in Nepal, is apparently overlooked despite approaching the peak season of the disease. The aim of this paper is to describe the double burden of COVID-19 and dengue in Nepal, particularly highlighting the co-circulation and possible coinfections. This has posed higher risk of increased severity, more severe cases and deaths in Nepal. Moreover, potential misdiagnosis of these viral diseases may lead to delayed or, inappropriate treatment and poor allocation of resources.

Detection and analysis of mycovirus-related RNA viruses from grape powdery mildew fungus Erysiphe necator.

The fungus, Erysiphe necator Schw., is an important plant pathogen causing powdery mildew disease in grapevines worldwide. In this study, high-throughput sequencing of double-stranded RNA extracted from the fungal tissue combined with bioinformatics was used to examine mycovirus-related sequences associated with E. necator. The results showed the presence of eight mycovirus-related sequences. Five of these sequences representing three new mycoviruses showed alignment with sequences of viruses classified in the genus Alphapartitivirus in the family Partitiviridae. Another three sequences representing three new mycoviruses showed similarity to classifiable members of the genus Mitovirus in the family Narnaviridae. These mycovirus isolates were named Erysiphe necator partitivirus 1, 2, and 3 (EnPV 1-3) and Erysiphe necator mitovirus 1, 2, and 3 (EnMV 1-3) reflecting their E. necator origin and their phylogenetic affiliation with other mycoviruses.

Evaluation of Anterolateral Plating of Distal Third Tibial Fractures.

Background Distal one-third tibial fractures with or without articular involvement can be difficult to manage. Variety of treatment methods have been suggested for these injuries, including conservative treatment, external fixation with or without limited internal fixation, intramedullary nailing, plate fixation (medial or anterolateral) and more recently minimally invasive plate osteosynthesis (MIPO). All of these techniques have advantages and disadvantages. None of these techniques can be considered the "gold standard" for these injuries. Objective The objective of this prospective study was to evaluate the results of anterolateral plating of these fractures. Method Forty-five fractures of distal third of tibia were treated with open reduction and internal fixation with anterolateral tibial plate from December 2011 to December 2016. All the patients were followed up at least for nine months for the study. Radiological union was finally assessed in nine months. Result All the fractures united within nine months of plating without angulation in sagittal or coronal plane. One patient (2%) had limb length shortening of more than one cm. Full range of motion of ankle and knee joint was achieved compared to the normal side by nine months follow up. 17 (38%) patients developed marginal skin necrosis. Three (7%) patients developed superficial wound infection. These complications were seen more in patients in whom posterior below knee slab was used for pre-operative splintage (as compared to calcaneal traction). Conclusion Hence distal one-third tibial fractures with or without articular involvement can be treated with anterolateral tibial plate.

Acetylamine derivative of diospyrin, a plant-derived binaphthylquinonoid, inhibits human colon cancer growth in Nod-Scid mice.

Anticancer activity of diospyrin and its derivatives (1-5) was evaluated against thirteen human cell lines. Compared to diospyrin (1), the acetylamine derivative (4) exhibited increase in cytotoxicity, particularly in HT-29 colon cancer cells, showing GI50 values of 33.90 and 1.96 µM, respectively. Also, enhanced toxicity was observed when cells, pre-treated with compound 4, were exposed to radiation. In vivo assessment of 4 was undertaken on tumour-bearing Nod-Scid mice treated at 4 mg/kg/day. Significant reduction in relative tumour volume (~86-91 %) was observed during the 12th-37th days after drug treatment. Increased caspase-3 activity and DNA ladder formation was observed in HT-29 cells after treatment with 4, suggesting induction of apoptotic death after drug treatment. Moreover, flow cytometric determination of Annexin V- FITC positive and PI negative cells demonstrated 17.4, 26.4, and 27.9 % of early apoptosis, respectively, upon treatment with 5, 10 and 25 µM of 4. HT-29 cells after treatment with 4 (1-25 µM) revealed ~2.5- 3- folds generation of ROS. Furthermore, concentration dependent decrease of mitochondrial trans-membrane potential (∆ψm), and expression of Bcl-2/Bax and other marker proteins suggested involvement of mitochondrial pathway of cell death. Overall, our results demonstrated the underlying cell-death mechanism of the plant-derived naphthoquinonoid (4), and established it as a prospective chemotherapeutic 'lead' molecule against colon cancer.

Microbial Variants from Iron Ore Slimes: Mineral Specificity and pH Tolerance.

This paper describes the isolation of the native bacterial strains from the iron ore mines slime pond and its extremophilic characteristics. The two microbial isolates designated as CNIOS-1 and CNIOS-2 were grown in selective silicate broth at pH 7.0 and the organisms were tested for their selective adhesion on silicate and alumina minerals. The silicate bacteria with their exopolymers are very potent to grow over aluminosilicates. It was established that CNIOS-1 grew preferentially in the presence of silicate mineral compared to CNIOS-2 which grew in the presence of alumina. The organisms were tested for growth at various pH and trials were carried to define their efficacy for eventual applications to remove gangue minerals of silica and alumina from the raw material.

Enhanced thorium decorporation and mitigation of toxicity through combined use of Liv52® and diethylenetriamine pentaacetate.

Thorium-232 (Th-232) is a promising fuel for advanced nuclear reactors. However, in case of internal human exposure to Th, there is currently no effective modality for its removal from liver and skeleton or for mitigating its effect. The FDA-approved agent, diethylenetriaminepentaacetate (DTPA), can remove Th and other actinides from blood circulation only. For the first time, a rationally-selected polyherbal hepatoprotective i.e. Liv52® (L52S), was evaluated in-combination with DTPA for its Th decorporation ability in Swiss mice. Inductively-coupled plasma mass spectroscopic analysis showed that oral administration of L52S in conjunction with DTPA significantly decreased Th burden from liver (20 %) and skeleton (33 %) as well as enhanced Th excretion (∼2.5 folds) through urine in comparison to DTPA or L52S alone. The combinatorial therapy was found to be complementary in-action, ameliorating Th-induced tissue damage in liver, spleen, and bone more effectively than monotherapy. Furthermore, markers of liver function (alanine transaminase) and liver inflammation and fibrosis (NF-κB & keratin) further validated the beneficial effect of L52S. The human consumption of L52S for various liver disorders further supports its clinical application for Th decorporation and mitigation of its health effects.

Cytokine profile of conditioned medium from human tumor cell lines after acute and fractionated doses of gamma radiation and its effect on survival of bystander tumor cells.

Cytokines are known to play pivotal roles in cancer initiation, progression and pathogenesis. Accumulating evidences suggest differences in basal and stress-induced cytokine profiles of cancers with diverse origin. However, a comprehensive investigation characterising the cytokine profile of various tumor types after acute and fractionated doses of gamma-irradiation, and its effect on survival of bystander cells is not well known in literature. In the present study, we have evaluated the cytokine secretion profile of human tumor cell lines (HT1080, U373MG, HT29, A549 and MCF-7) either before (basal) or after acute (2, 6 Gy) and fractionated doses (3×2 Gy) of gamma-irradiation in culture medium obtained from these cells by multiplex bead array/ELISA. Moreover, clonogenic assays were performed to evaluate the effect of conditioned medium (CM) on the survival and growth of respective cells. Based on the screening of 28 analytes, our results showed that the basal profiles of these cell lines varied considerably in terms of the number and magnitude of secreted factors, which was minimum in MCF-7. Interestingly, TNF-α, IL-1ß, PDGF-AA, TGF-ß1, fractalkine, IL-8, VEGF and GCSF were found in CM of all the cell lines. However, secretion of certain cytokines was cell line-specific. Moreover, CM caused increase in clonogenic survival of respective tumor cells (in the order HT1080>U373MG>HT29>A549>MCF-7), which was correlated with the levels of IL-1ß, IL-6, IL-8, GMCSF and VEGF in their CM. After irradiation, the levels of most of the cytokines increased markedly in a dose dependent manner. The fold change in cytokine levels was lower in irradiated conditioned medium (ICM) of tumor cells collected after fractionated than respective acute dose, except in MCF-7. Interestingly, amongst these cell lines, the radiation-induced fold increase in cytokine levels was maximum in ICM of A549 cells. Moreover, bystander A549 cells treated with respective ICM showed dose dependent decrease in clonogenic survival. In conclusion, present study revealed the similarities and subtle differences in basal and radiation-induced cytokine profile of different tumor cell lines, and its influence on growth and survival of respective bystander cells. These findings may add a new dimension to our current understanding about role of cytokines in cancer biology.

In silico comparative analysis and expression profile of antioxidant proteins in plants.

The antioxidant system in plants is a very important defensive mechanism to overcome stress conditions. We examined the expression profile of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) using a bioinformatics approach. We explored secondary structure prediction and made detailed studies of signature pattern of antioxidant proteins in four plant species (Triticum aestivum, Arabidopsis thaliana, Oryza sativa, and Brassica juncea). Fingerprinting analysis was done with ScanProsite, which includes a large collection of biologically meaningful signatures. Multiple sequence alignment of antioxidant proteins of the different plant species revealed a conserved secondary structure region, indicating homology at the sequence and structural levels. The secondary structure prediction showed that these proteins have maximum tendency for α helical structure. The sequence level similarities were also analyzed with a phylogenetic tree using neighbor-joining method. In the antioxidant enzymes SOD, CAT and APX, three major families of signature were predominant and common; these were PKC_PHOSPHO_SITE, CK2_PHOSPHO_SITE and N-myristoylation site, which are functionally related to various plant signaling pathways. This study provides new strategies for screening of biomodulators involved in plant stress metabolism that will be useful for designing degenerate primers or probes specific for antioxidant. These enzymes could be the first line of defence in the cellular antioxidant defence pathway, activated due to exposure to abiotic stresses.

Comparative study of microscopy and polymerase chain reaction for the diagnosis of suspected visceral leishmaniasis patients in Nepal.

BACKGROUND: Visceral leishmaniasis is potentially fatal protozoan diseases caused by Leishmania donovani. Nepal is an endemic region in which visceral leishmaniasis causes a major public health problem in the lowland areas that border the endemic areas of Bihar state in India. Accurate diagnosis to inform treatment is a first step in achieving the goal of visceral leishmaniasis elimination from South East Asian regions by 2020. OBJECTIVE: The objective of the present study was to compare between the Microcopy and polymerase chain reaction for diagnosis of visceral leishmaniasis. METHODS: In the present study, 236 bone marrow aspirations were collected from suspected visceral leishmaniasis patients in Janakpur Zonal Hospital, Dhanusa district, Terai region of Nepal in between 2003-2007. We evaluated bone marrow samples by microscopic examination with subsequent testing of the same sample by polymerase chain reaction and sequence analysis. RESULTS: Giemsa's solution stained bone marrow slides stored for over five years were used for polymerase chain reaction amplification. The result showed that 71% were polymerase chain reaction positive and 56% were microscopic positive. Out of 104 microscopic negative bone marrow samples, 15% of samples were positive by polymerase chain reaction. CONCLUSION: Polymerase chain reaction could make a very good option for diagnosis by using less or non-invasive material from visceral leishmaniasis patients in endemic areas of Nepal.

Prognostic value of rapid test for diagnosis of dengue in Nepalese patients during 2010 epidemic.

BACKGROUND: Dengue is an emerging vector borne disease in Nepal and rapid diagnostic test is important for early diagnosis of the disease. OBJECTIVES: The aim of the study was to evaluate the diagnostic accuracy of commonly used rapid immunochromatographic test kit in Nepal during 2010 dengue epidemic and to assess disease burden of dengue. METHODS: A total of 131 acute and nonacute serum samples were collected during recent epidemic of dengue in 2010 from clinically suspected Nepalese patients of different hospitals. Rapid immunochromatographic test kit was used for early diagnosis and enzyme immunosorbent was chosen as a reference assay. RESULTS: The sensitivity and specificity of rapid test was 70% and 76.54% respectively whereas the prevalence of the disease was 38.17%. The odds ratio for males was 1.8 however; the association with the disease was statistically not significant. CONCLUSION: The diagnostic accuracy of rapid immunochromatographic test for dengue diagnosis was low (k=0.46). So, it should be substituted by highly sensitive test device for prompt diagnosis and health personnel should consider appropriate timing of sample collection for better performance of rapid test.

Interaction of glucosamine with uracil and thymine: a computational study.

The present study delves into the interaction of the monomer of glucosamine with uracil and thymine in vacuum and in different phases by density functional theory (DFT). Both the molecular geometries were optimized at B3LYP with a 6-31G(d,p) basis set. The binding energy, interaction energy, and solubility were calculated from the optimized molecular geometry. The dipole moment and the electronic energies were found of the optimized product in different solvents (water, ethanol, methanol, heptane, cyclohexane, and CCl4) which describes the solubility of the interactive molecule in polar and non-polar solvents. The electronic energies are nearly the same for all the solvents. Observed theoretical results are expected to guide future relevant experimental research on gene delivery by glucosamine. This will also help in enhancing pharmaceutical research as carrier drug delivery, tissue repair, gene delivery, spermicidal activity, anti-tumor, and anti-microbial resistance.

The occurrence of amino acid substitutions D96N and S242N in VP7 of emergent G2P[4] rotaviruses in Nepal in 2004-2005: a global and evolutionary perspective.

Rotavirus is the leading cause of severe diarrhea among children worldwide. Strains with G2P[4] have captured recent attention because of its abrupt increase or re-emergence in many locations in the world. In Nepal, G2P[4] strains were detected at a rate of 1% in 2003-2004, but increased to 33% in 2004-2005. Thus, the VP7 genes of 45 emergent G2 strains from Nepal were sequenced and analyzed together with a total of 339 G2VP7 sequences detected over the last 34 years that were compiled from the DNA database. We found that all Nepalese VP7 sequences had a substitution from aspartic acid to asparagine at residue 96 (D96N) that was the hallmark of the lineage termed sublineage IVa, which replaced virtually all globally circulating G2 strains during the last decade. Within sublineage IVa, further sublineages emerged, of which a sublineage termed IVa-3 was identified to have another amino acid substitution from serine to asparagine at 242 (S242N). This sublineage, to which all Nepalese sequences belonged, now became the most frequent G2 sequence globally. In conclusion, the G2VP7 gene evolved in a dynamic fashion such that new lineages emerged within the previously dominant lineage, one of which became subsequently dominant.

Trends of rotavirus in Nepal.

BACKGROUND: Rotavirus gastroenteritis is the major cause of morbidity and mortality in infants and young children worldwide. Safe and effective rotavirus vaccine is needed to have significant impact on severe rotavirus gastroenteritis. Currently, two live oral rotavirus vaccines have been licensed in many countries. Knowledge on distribution of human rotavirus of G and P types are essential before rotavirus vaccines are introduced in the target populations. OBJECTIVE: To observe the trends of rotavirus strains in children below five years of age, during the years, 2003-2005 in Nepal. METHODS: Stool specimen collected from children with acute diarrhea who were referred to observation unit or hospitalized in Kanti Children Hospital between 2003 and 2005 were examined. Meteorological data was obtained from Ministry of Environment, Nepal to examine the possibility on the impact of weather on rotavirus infection. RESULTS: Of 1250 stool specimens, 271(22%) were positive for rotavirus by Rotaclone ELISA. G1 was the most common serotype in the first year of study, and G2 in the following year. G12 serotype emerged and remained predominant in two consecutive years. In addition, G9 and G3 emerged in the second year of the study. Children less than three years of age were commonly affected. The records reveal that rotavirus infection is related to the climate, and is commonly seen in the dry season, peaking in January. CONCLUSIONS: Continued surveillance of different regions is needed to monitor the trend of rotavirus strains and to establish rotavirus disease burden, which will help policy makers to make a decision in introducing rotavirus vaccine in Nepal.

Influence of polyethylene glycol plasticizer on the structural and electronic properties of PEO-NaI complex: a density functional study.

Ab initio study has been carried out to investigate the influence of low molecular weight polyethylene glycol (PEG) plasticizer on structural and electronic properties of the polyethylene oxide-sodium iodide (PEO-NaI) polymer-metal complex. DOS and PDOS analysis provided a quantitative explanation of the electronic bandgap of the PEO-NaI and PEO-PEG-NaI system. Hirshfeld population charge analysis (HPA) explains better dissociation of NaI in presence of polyethylene glycol, based on the Hard Soft Acid Base Principle. Also, an increase in amorphic content of polymer system is observed with the addition of PEG, evident from the increment in the strength of anti-bonding orbitals in COOP plot. Bond strength of the polymeric system is also found to be affected with the addition of plasticizer. The findings provide an avenue that the present polymer system [PEO-PEG-NaI] is a potential candidate to be used as an electrolyte for next-generation energy storage technology.

TRAF6-IRF5 kinetics, TRIF, and biophysical factors drive synergistic innate responses to particle-mediated MPLA-CpG co-presentation.

Innate immune responses to pathogens are driven by co-presentation of multiple pathogen-associated molecular patterns (PAMPs). Combinations of PAMPs can trigger synergistic immune responses, but the underlying molecular mechanisms of synergy are poorly understood. Here, we used synthetic particulate carriers co-loaded with monophosphoryl lipid A (MPLA) and CpG as pathogen-like particles (PLPs) to dissect the signaling pathways responsible for dual adjuvant immune responses. PLP-based co-delivery of MPLA and CpG to GM-CSF-driven mouse bone marrow-derived antigen-presenting cells (BM-APCs) elicited synergistic interferon-ß (IFN-ß) and interleukin-12p70 (IL-12p70) responses, which were strongly influenced by the biophysical properties of PLPs. Mechanistically, we found that MyD88 and interferon regulatory factor 5 (IRF5) were necessary for IFN-ß and IL-12p70 production, while TRIF signaling was required for the synergistic response. Both the kinetics and magnitude of downstream TRAF6 and IRF5 signaling drove the synergy. These results identify the key mechanisms of synergistic Toll-like receptor 4 (TLR4)-TLR9 co-signaling in mouse BM-APCs and underscore the critical role of signaling kinetics and biophysical properties on the integrated response to combination adjuvants.

Functional outcome of operatively treated displaced intra-articular calcaneal fractures using two parallel contoured reconstruction plates.

INTRODUCTION: The treatment of displaced intra-articular calcaneal fracture is controversial. Conventionally, they were treated non-operatively. However, some surgeons are now operatively treating these fractures because of continuing dissatisfaction with the outcome of conservative treatment of these fractures and improvements that have occurred in surgical techniques and complication rates. OBJECTIVE: The aim of this study was to determine the functional outcome of operatively treated displaced intra-articular calcaneal fractures using two parallel contoured reconstruction plates. MATERIALS AND METHODS: 12 patients with 14 displaced intra-articular calcaneal fractures involving the subtalar joint were included in the study conducted between July 2005 and December 2008. The fracture site was exposed using extended lateral approach. Internal fixation was done by two nearly parallel 3.5mm reconstruction plates and screws contoured to form a gentle curve in all cases with the fi rst plate fixed just below the articular surface. At the end of follow up, the patients' foot function was assessed by Calcaneal Fracture Scoring System of Kerr et al. Patients were also inquired about their satisfaction with their treatment outcome. RESULTS: The patients were followed up for duration of 12 to 24 months (mean 15.64 months). The outcome score as measured by Calcaneal Fracture Scoring System ranged from 48 to 94 (mean 83.64). 11 of 12 patients (91.6 %) were satisfied with the treatment. CONCLUSION: Displaced intra-articular fractures treated by open reduction and internal fixation, using two nearly parallel, contoured reconstruction plates through an extensile lateral approach and following the principles of treatment of intraarticular fractures, have good functional results with high patient satisfaction rate.

Osteosynthesis of intercondylar humerus fracture using Bryan and Morrey approach.

BACKGROUND: The olecranon approach has been the gold standard for surgical approaches to fracture fixation of distal articular surface of humerus. Although it provides a good exposure, it also has disadvantages of delayed union, nonunion and implant related complications at the osteotomy site. OBJECTIVE: The aim of this study was to determine the functional outcome of displaced intra-articular distal humerus fracture fixation using an alternative approach: the Bryan and Morrey approach. MATERIALS AND METHODS: Twenty patients with twenty AO type C1 and C2 intercondylar fractures of the distal humerus had bicolumnar fixation of the distal humerus with two contoured reconstruction plates and screws on the dorsal surface or various combinations of a single reconstruction plate, screws and K-wires using a Bryan and Morrey approach. Twelve of the patients were male and eight were female. The average age of the patients was 44.8 years. Eleven patients had sustained the injury as result of fall and nine of the patients had sustained it in road traffic accidents. Right elbow was involved in fifteen patients and left in five. All patients were followed up for 12 months post operatively. RESULTS: All twenty fractures had united at 4 months follow-up. The mean fixed flexion deformity was 9.0º (range 0º-15º) and the mean arc of motion was 115.0 º (range 85 º- 130º). All patients had grade 4 triceps strength and stable elbows at the end of 12 months follow up. One patient had deep seated wound infection resulting in necrosis of the triceps tendon requiring a second operative procedure. CONCLUSIONS: Bryan and Morrey approach is a simpler, easier and better approach as compared to the other posterior approaches to the elbow joint, and therefore, can be used as the approach of choice for fixation of fractures of the distal articular surface of humerus.

Development of surface functionalized hydroxyapatite nanoparticles for enhanced specificity towards tumor cells.

Nanoparticles coupled with targeting moieties have attracted a great deal of attention for cancer therapy since they can facilitate site-specific delivery of drug and significantly limit the side effects of systemic chemotherapy. In this study, our aim is to develop surface functionalized hydroxyapatite nanoparticles, which could provide binding sites for a cancer cell targeting ligand, folic acid (FA) as well as an anticancer drug, doxorubicin hydrochloride (DOX). In order to attain dual functionalities, hydroxyapatite nanoparticles were functionalized with gelatin molecules. Gelatin, being a protein has both carboxyl and amine moieties, which makes it suitable for binding of DOX and FA. FA was chemically conjugated to the nanoparticles through an EDCNHS coupling reaction. The formation of single-phase hydroxyapatite nanostructure was ascertained by X-ray diffraction studies and the presence of organic moieties on the surface of nanoparticles was evident from Fourier transform infrared spectroscopy, thermogravimetric analysis and U.V.-visible spectroscopy. The FA-conjugated nanoparticles (FA-Gel-HANPs) showed high affinity towards DOX and pH-responsive sustained release of drug with higher release rate under acidic pH conditions, desired for cancer therapy. The FA-Gel-HANPs showed negligible cytotoxicity towards different cell lines (HepG2, WEHI-164, KB, WI-26 VA4 and WRL-68). However, DOX loaded nanoparticles (DOX-FA-Gel-HANPs) exhibited significant toxicity towards these cells, which was however highest in folate receptor (FR)-overexpressing, KB cells. These results were correlated with enhanced cellular uptake of DOX-FA-Gel-HANPs in KB cells in comparison to FR-deficient, WRL-68 cells studied by confocal laser scanning microscopy and flow cytometry. Moreover, cell cycle analysis in KB cells, showed higher sub-G1 population, indicating apoptosis as one of the cell death mechanisms. Overall, this study suggests that DOX-FA-Gel-HANPs could serve as a promising tumor-targeted drug delivery system.

Glutamic acid-coated Fe3O4 nanoparticles for tumor-targeted imaging and therapeutics.

We have developed surface functionalised Fe3O4 magnetic nanoparticles (MNPs) based system that can be used for tumor-targeted multimodal therapies and MR imaging. Biocompatible, non-essential amino acid (glutamic acid) was introduced onto the surface of Fe3O4 MNPs to provide functional sites for binding of chemotherapeutic drugs. These glutamic acid-coated Fe3O4 MNPs (GAMNPs) exhibit good water-dispersibility, magnetic responsivity and pH dependent charge conversal feature. The magnetic core as well as organic shell of GAMNPs was characterized by XRD, TEM, DLS, FTIR, PPMS and UV-visible spectroscopy and zeta-potential analyzer etc. The broad spectrum anticancer drugs, doxorubicin hydrochloride (DOX) and methotrexate (MTX) were electrostatically and covalently conjugated to the surface of GAMNPs, respectively for combination chemotherapy. These dual drugs loaded system (DOX-MTX-GAMNPs) shows pH dependent release behaviour of both the drugs and enhanced toxicity towards breast cancer cell line (MCF-7) as compared to their individual treatment. Fluorescence microscopy and flow cytometric analyses confirmed the successful uptake of drug loaded system into MCF-7 cell lines. Further MTX being analogue of folic acid, its co-delivery with DOX would help in internalization of both the drugs into MCF-7 cells. These GAMNPs also show good heating efficiency under AC magnetic field (Intrinsic loss power, ILP = 0.95 and 0.73 and 0.48 nHm2/Kg at Fe concentration of 0.5, 1 and 2 mg/ml, respectively) and transverse relaxivity (r2 = 152 mM-1 s-1) indicating their potential capability for hyperthermia therapy and MRI tracking. Furthermore, it has been observed that the combination of chemotherapeutic drugs and hyperthermia leads to an enhancement of cytotoxicity in MCF-7 cells.

Role of mitochondrial oxidative stress in the apoptosis induced by diospyrin diethylether in human breast carcinoma (MCF-7) cells.

Mitochondria and associated oxidative stress have been shown to play critical roles in apoptotic death induced by various stress agents. Previously, we reported the antitumor property of diospyrin (D1), a plant-derived bisnaphthoquinonoid, and its diethylether derivative (D7), which was found to cause apoptotic death in human cancer cell lines. The present study aims to explore the relevant mechanism of apoptosis involving generation of cellular reactive oxygen species (ROS) by D7 in human breast carcinoma (MCF-7) cells. It was found that while D7 inhibited the proliferation of tumor cells, the associated apoptosis induced by D7 was prevented by treating the cells with N-acetyl-L-cysteine (NAC), an antioxidant, and cyclosporine A (CsA), an inhibitor of mitochondrial permeability transition (MPT). Experiments using suitable inhibitors also demonstrated that D7 could alter the electron flow in mitochondrial electron transport chain by affecting target(s) between complex I and complex III, and indicated the probable site of D7-induced generation of ROS. These results were further supported by confocal microscopic observation on changes in mitochondrial organization and shape in cells treated with D7. Taken together, the results of our study clearly suggested that the apoptosis induced by D7 would involve alteration of MPT, cardiolipin peroxidation, migration of Bax from cytosol to mitochondria, decreased expression of Bcl-2, and release of cytochrome c, indicating oxidative mechanism at the mitochondrial level in the tumor cells.