Thiadiazole Functionalized Salicylaldehyde-Schiff Base as a pH-responsive and chemo-reversible "Turn-Off" fluorescent probe for selective cu (II) detection: Logic Gate Behaviour and Molecular Docking Studies.

A novel thiadiazole functionalized schiff base chemoreceptor (E)-2,4-dichloro-6-(((5-mercapto-1,3,4-thiadiazol-2-yl)imino)methyl)phenol (SB-1) has been synthesized and characterized spectroscopically by using various techniques. Its photophysical behaviour was scanned towards a variety of metal ions in mixed aqueous media. The chemosensor (SB-1) displayed excellent selectivity towards Cu2+ ion through fluorescent diminishment (turn-off phenomenon). Colorimetric analyses showed a rapid colour change from yellow to dark red under visible light upon addition of Cu2+ ions. Interestingly, the original yellow colour reappeared back instantly after the addition of EDTA2- anions, thus confirming the reversible nature of SB-1. Competitive experiments validated no interference from the other co-existing metal ions in the recognition process of SB-1 towards Cu2+ ion. Job's plot confirmed 1:1 binding stoichiometry between SB-1 and Cu2+ ion with the binding constant value of 3.87 × 104 M- 1. The limit of detection was determined to be 1.01 × 10- 7 M suggesting good sensitivity of SB-1 towards Cu2+ ions. Furthermore, pH-dependent UV-Vis spectral behaviour of SB-1 confirmed that it could act as an effective optical pH-sensor for highly acidic environment as well. Portable nature of probe SB-1 was explored by fabricating "easy-to-use" paper test strips, which allow robust and rapid detection of Cu2+ ions. Based on the multi-responsive properties of SB-1, a 'NOR' logic gate was constructed by applying Cu2+ and EDTA2- as chemical inputs (ln1: Cu2+, ln2: EDTA2-) while emission intensity observed at 560 nm was considered as output signal (O1). DFT optimized geometries confirmed that chemosensor SB-1 exists in Azo form (Enol form) in its ground state. Molecular docking of the SB-1 and its copper complex, into the binding site of TRK protein tyrosine kinase (PDB: 1t46) was also carried out to explore their biological activity and their potential use as TRK inhibitors.

Novel Unsymmetric 3,5-Bis(benzylidene)-4-piperidones That Display Tumor-Selective Toxicity.

Two series of novel unsymmetrical 3,5-bis(benzylidene)-4 piperidones 2a-f and 3a-e were designed as candidate antineoplastic agents. These compounds display potent cytotoxicity towards two colon cancers, as well as several oral squamous cell carcinomas. These compounds are less toxic to various non-malignant cells giving rise to large selectivity index (SI) figures. Many of the compounds are also cytotoxic towards CEM lymphoma and HL-60 leukemia cells. Representative compounds induced apoptotic cell death characterized by caspase-3 activation and subG1 accumulation in some OSCC cells, as well as the depolarization of the mitochondrial membrane potential in CEM cells. A further line of inquiry was directed to finding if the SI values are correlated with the atomic charges on the olefinic carbon atoms. The potential of these compounds as antineoplastic agents was enhanced by an ADME (absorption, distribution, metabolism, and excretion) evaluation of five lead molecules, which revealed no violations.

Co-delivery of Vorinostat and Etoposide Via Disulfide Cross-Linked Biodegradable Polymeric Nanogels: Synthesis, Characterization, Biodegradation, and Anticancer Activity.

Treatment regimens for cancer patients using single chemotherapeutic agents often lead to undesirable toxicity, drug resistance, reduced uptake etc. Combination of two or more drugs is therefore becoming an imperative strategy to overcome these limitations. A step forward can be taken through delivery of the drugs used in combination via nanoparticles. Co-administration of chemotherapeutic drugs encapsulated in nanoparticles has been shown to result in synergistic effects and enhanced therapeutic efficacy. In present study, we explored the combination treatment of histone deacetylase inhibitor vorinostat (VOR) and topoisomerase II inhibitor etoposide (ETOP). The concurrent combination treatment of VOR and ETOP resulted in synergistic effect on human cervical HeLa cancer cells. VOR and ETOP were encapsulated into poly(ethylene glycol) monomethacrylate (POEOMA)-based disulfide cross-linked nanogels. The nanogels were synthesized using atom transfer radical polymerization (ATRP) via cyclohexane/water inverse mini-emulsion and were degradable in presence of intracellular glutathione (GSH) concentration. Both the drugs were loaded into the nanogels by physical encapsulation method and characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD), dynamic light scattering (DLS), and differential scanning calorimetry (DSC). Both VOR- and ETOP-loaded nanogels showed sustained release profile. Furthermore, combination treatment drugs encapsulated of POEOMA nanogel demonstrated enhanced synergistic cytotoxic effect compared with combination of free drugs. Enhanced synergistic cell killing efficiency of drug-loaded POEOMA nanogels was due to increased apoptosis via caspase 3/7 activation. Therefore, combination of VOR- and ETOP-loaded PEG-based biodegradable nanogels may provide a promising therapy with enhanced anticancer effect.

Tumor microenvironment responsive nanogels as a smart triggered release platform for enhanced intracellular delivery of doxorubicin.

The fabrication of novel and intelligent delivery systems that can effectively deliver therapeutics to the targeted site and release payload in enhanced/controlled manner is highly desired to overcome the multiple challenges in chemotherapy. The present article demonstrates the potential application of dual stimuli responsive nanogels as tumor microenvironment targeted drug delivery carrier. Disulfide cross-linked pH and redox responsive PEG-PDMAEMA nanogels were synthesized by atom transfer radical polymerization (ATRP). The nanogels were characterized by nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The PEG-PDMAEMA nanogels exhibited dual stimuli-responsive release of the encapsulated model anticancer drug (doxorubicin, DOX) due to the acidic pH-response of dimethyl amine group in PDMAEMA and reductive cleavage of the disulfide linkages. A relatively higher release of DOX was observed from the nanogels at pH 5.0 than at pH 7.4. DOX release was further accelerated in tumor simulated environment of pH 5.0 and 10 mM glutathione (GSH). Confocal microscopy images revealed that DOX-loaded PEG-PDMAEMA nanogels can rapidly internalize and effectively deliver the drug into the cells. The nanogels exhibited higher cytotoxicity in GSH-OEt pretreated HeLa cells than untreated cells. The dual stimuli responsive nanogels synthesized in this study exhibited many favorable traits, such as pH and redox dependent controlled release of drug, biodegradability, biocompatibility, and enhanced cytotoxicity, which endow them as a promising candidate for anticancer drug delivery.

Critical analysis of two cases of major crossmatch incompatibility in tertiary care hospital in Delhi.

Rh blood group is one of the most complexes of the human blood groups system. RHD gene encodes the D antigen, and the RHCE encodes the C, c, E, and e antigens. Out of these, Rh D antigen is the most immunogenic while e antigen is the least immunogenic. Rh antibodies are produced in Rh-negative individuals following sensitization which occurs either through pregnancy or during blood transfusion. We hereby report two cases of anti-e antibody, both presenting as major crossmatch incompatibility.

Critical evaluation of donor direct antiglobulin test positivity: Implications in cross-matching and lessons learnt.

Direct Antiglobulin Test is a method of demonstrating the presence of antibody/ complement bound to red cell membrane by using AHG to form a visible agglutination reaction. DAT positivity is seen in immune mediated haemolytic anaemias, however rarely non immune mediate haemolytic anaemias also show DAT positivity. DAT positivity predictive of 83% of autoimmune haemolytic anaemia and 1.4% cases without haemolytic anaemia. Screening of blood donors for DAT is usually not recommended traditionally by any guidelines. However DAT positivity is reported in 0.008% of donors. On extensive search of literature we could find only very few studies on DAT positivity in donors. We report two cases of DAT positive donors with no clinical or laboratory evidence of hemolysis.

PEG-coumarin nanoaggregates as π-π stacking derived small molecule lipophile containing self-assemblies for anti-tumour drug delivery.

Polymeric self-assemblies formed by non-covalent interactions such as hydrophobic interactions, hydrogen bonding, π-π stacking, host-guest and electrostatic interactions have been utilised widely and exhibit controlled release of encapsulated drug. Beside carrier-carrier interactions, small molecule amphiphiles exhibiting carrier-drug interactions have recently been an area of interest for cancer drug delivery, as most of the hydrophobic anti-tumour drugs are aromatic and exhibit π-π conjugated structure. In the present study PEG-coumarin (PC) conjugates forming self-assembled nanoaggregates were synthesised with PEG (polyethylene glycol) as hydrophilic block and coumarin as small molecule lipophilic segment. Curcumin (CUR) as model conjugated aromatic drug was loaded in to the nanoaggregates via dual hydrophobic and π-π stacking interactions. The interactions between the conjugates and CUR, drug release profile and in vitro anti-tumour efficacy were investigated in detail. CUR-loaded nanoaggregate self-assembly was driven by π-π interactions and a maximum loading level of about 18 wt.% (~60 % encapsulation efficiency) was achieved. The average hydrodynamic diameter (Dav) was in the range of 120-160 nm and a spherical morphology was observed by transmission electron microscopy (TEM). A sustained release of CUR was observed for 90 h. Cytotoxicity evaluation of CUR-loaded nanoaggregates on pancreatic cancer cell lines indicated higher efficacy, IC50 ~11 and ~15 µM as compared to free CUR, IC50 ~14 and ~20 µM on human pancreatic carcinoma (MIA PaCa-2) and human pancreatic duct epithelioid carcinoma (PANC-1) cell lines respectively. PC conjugates provided a new strategy of fabricating nanoparticles for drug delivery and may form the basis for the development of advanced biomaterials in near future.

Development of 1,3,4-oxadiazole thione based novel anticancer agents: Design, synthesis and in-vitro studies.

A series of new 1,3,4-oxadiazole-2(3H)-thione analogues (3a to 3o) have been designed, synthesized and evaluated for their anticancer activity. Four different cancerous cell lines viz. HeLa (cervical), U-87 (glioblastoma), Panc (pancreatic) and MCF-7 (breast) were used to assess the potency of the synthesized compounds as anticancer agents. Among them 3i and 3j showed promising cytotoxicity against HeLa cell line. Further, 3i and 3j successfully inhibited cell cycle progression and displayed cell death in HeLa cells via apoptosis as visualized by Annexin V APC and DNA fragmentation assay. 3i and 3j induced caspase-3 activation, PARP cleavage, increase in expression of proapoptotic protein Bax and decrease in the expression of antiapoptotic protein Bcl-2. Also, 3i and 3j induced overexpression of p21 and decreased expression of cyclin B1 indicating the arrest of cells in G2-M phase of the cell cycle. Therefore, new lead compounds are being suggested having anticancer activity through cell cycle inhibition and apoptosis.

Thrombin Activable Fibrinolysis Inhibitor in Beta Thalassemia.

OBJECTIVES: To study plasma levels of Thrombin activable fibrinolysis inhibitor (TAFI) in children with ß-thalassemia major. METHODS: Fifty ß-thalassemia major patients, 1.4 to 17 y of age, with number of transfusions received varying from 21 to 162 were selected at random and complete blood count (CBC), coagulation parameters [Prothrombin time (PT), Activated partial thromboplastin time (aPTT), fibrinogen, D-dimer, protein C, protein S, antithrombin, Tissue plasminogen activator (t-PA), Plasminogen activator inhibitor (PAI-1)] and TAFI were performed. RESULTS: PT and aPTT were prolonged in 18 % and 30 % of cases respectively. Reduced activity of Protein C (PC) was observed in 50 % of cases and Protein S (PS) was reduced in 54 % of cases. t-PA levels were significantly higher in cases. TAFI levels were 17.24 ± 4.05 ng/ml which were significantly higher than the control group (15.01 ± 3.28; p = 0.003) No significant correlation of TAFI was observed with Hb, platelet counts, liver enzymes, serum ferritin, PC, PS, D-dimer, t-PA or PAI-1. CONCLUSIONS: There is an ongoing subclinical activation of coagulation cascade and fibrinolytic system in thalassemia major (TM) patients. Higher levels of TAFI in the present study with no significant correlation with other parameters were noted, thus pointing out to its independent role in contribution to hypercoagulable state in thalassemia. TAFI serves as a link between two limbs of hemostasis, with its higher levels promoting inhibition of fibrinolytic system and thus promoting a hypercoagulable state. Performing TAFI levels in thalassemic patients could help to detect the early coagulopathy in these patients and hence these patients can be closely monitored for any evidence of thrombosis.

Poly(ethylene glycol)-co-methacrylamide-co-acrylic acid based nanogels for delivery of doxorubicin.

Polymeric nanogels have been widely explored for their potential application as delivery carriers for cancer therapeutics. The ability of nanogels to encapsulate therapeutics by simple diffusion mechanism and the ease of their fabrication to impart target specificity in addition to their ability to get internalized into target cells make them good candidates for drug delivery. The present study aims to investigate the applicability of poly(ethylene glycol)-co-methacrylamide-co-acrylic acid (PMA)-based nanogels as a viable option for the delivery of doxorubicin (DOX). The nanogels were synthesized by free radical polymerization in an inverse mini-emulsion and characterized by nuclear magnetic resonance spectroscopy ((1)H NMR), Fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy (TEM), X-ray diffraction and differential scanning calorimetry. DOX was physically incorporated into the nanogels (PMA-DOX) and the mechanism of its in vitro release was studied. TEM experiment revealed spherical morphology of nanogels and the hydrodynamic diameter of the neat nanogels was in the range of 160 ± 46.95 nm. The size of the nanogels increased from 235.1 ± 28.46 to 403.7 ± 89.89 nm with the increase in drug loading capacity from 4.68 ± 0.03 to 13.71 ± 0.01%. The sustained release of DOX was observed upto 80 h and the release rate decreased with increased loading capacity following anomalous release mechanism as indicated by the value of diffusion exponent (n = 0.64-0.75) obtained from Korsmeyer-Peppas equation. Further, cytotoxicity evaluation of PMA-DOX nanogels on HeLa cells resulted in relatively higher efficacy (IC50~5.88 µg/mL) as compared to free DOX (IC50~7.24 µg/mL) thus demonstrating that the preparation is potentially a promising drug delivery carrier.

PEG-coumarin based biocompatible self-assembled fluorescent nanoaggregates synthesized via click reactions and studies of aggregation behavior.

HYPOTHESIS: Click chemistry has found wide application in drug discovery, bioconjugation reactions, polymer chemistry and synthesis of amphiphilic materials with pharmaceutical and biomedical applications. Triazole substitution via a click reaction alters photophysical properties of coumarin. Both coumarin and triazole moieties participate in π-π stacking interactions. Hence it should be possible to prepare fluorescent self-assembly systems by conjugation of coumarin to poly (ethylene glycol) (PEG) via click reactions exhibiting hydrophilic, hydrophobic and π-π stacking interactions. Moreover, the materials can be suitable platforms to assess fluorescence modulation effect of triazole substitution on coumarins. EXPERIMENTS: PEG supported coumarin conjugates were synthesized and the fluorescence modulation effect of the formation of triazole on coumarin was assessed. Their aggregation properties were studied by surface tension measurements, dynamic light scattering (DLS), transmission electron microscopy (TEM), fluorescence and (1)H NMR spectroscopy. FINDINGS: The conjugates were found to form nanoaggregates in the size range of 100-120 nm with a negative free energy of micellization (~-27 kJ mol(-1)) confirming aggregation and self-assembly. The Quantum yield of 4-methyl-7-propargylcoumarin (7P4MC) was enhanced after triazole formation with azide functionalized PEG (methoxy-PEG350 azide). The conjugates were found to exhibit π-π stacking interactions in addition to hydrophilic and hydrophobic interactions. They were found to be biocompatible with human pancreatic cancer cells.

Gallic acid loaded disulfide cross-linked biocompatible polymeric nanogels as controlled release system: synthesis, characterization, and antioxidant activity.

In this article, a sustained release formulation of the antioxidant gallic acid (GA) is presented in the form of glutathione responsive disulfide cross-linked poly(ethylene glycol)-based nanogels synthesized via aqueous inverse miniemulsion using atom transfer radical polymerization. The particle size was found to be in the range from 227 ± 51.78 to 573.3 ± 207.2 nm at three drug loading levels achieved i.e. 6.6, 14.26, and 18.29 wt.% of the nanogels with loading efficiency in the range of 60-70%. The release profile of the GA studied at three drug loading levels suggested a controlled release and the nanogels were capable of scavenging radicals and retained the antioxidant activity. The GA-loaded nanogels were found to be biocompatible on human cervical cancer cell lines (HeLa). DCFH-DA (2,7-dichlorofluorescin diacetate) assay evidenced that the nanogels were capable of scavenging the reactive oxygen species in cellular environment.