Structures and dynamics of peptide and peptidomimetic inhibitors bound to the NS2B-NS3 protease of the ZIKA virus.

Infections caused by the Zika virus (ZIKV) have detrimental effects on human health, in particular on infants. As no potent drug or vaccine is available to date to contain this viral disease, it is necessary to design inhibitors that can target the NS2B-NS3 protease of the ZIKV, which is mainly responsible for the proliferation of the virus inside the host cells . Here, molecular dynamics (MD) simulation and molecular mechanics energies combined with the generalized Born and surface area continuum solvation model (MM/GBSA) are used to understand the binding modes and stabilities of R, KR, KKR, WKR, WKKR, YKKR, and FKKR peptide inhibitors bound to the NS3-NS2B protease. The results are compared with the corresponding results obtained for covalent (compound 1) and non-covalent (compound 4*) peptidomimetic inhibitors . It is revealed that peptide inhibitors can bind strongly with the ZIKV protease with the ΔGbind ranging from -12 kcal/mol to -73 kcal/mol. Among these peptides, YKKR is found to make the most stable complex with the protease and fully occupy the electrostatically active substrate binding site. Hence, it would inhibit the protease activities of ZIKV strongly. The residue-wise decomposition of ΔGbind indicates that Asp75, Asp129, Tyr130, Ser135, Gly151, Asn152, Glys153, and Tyr161 of NS3 and Ser81, Asp83, and Phe84 of NS2B play a prominent role in the inhibitor binding. Therefore, any future design of inhibitors should be aimed to target these residues.

Probing the effect of a room temperature ionic liquid on phospholipid membranes in multilamellar vesicles.

The large number of potential applications of ionic liquids (ILs) requires an understanding of their environmental impacts including their adverse effects on microorganisms living in soil and water. The molecular mechanism of toxic activities of these liquids is yet to be understood in detail. Any foreign molecules, interacting with an organism, have to encounter first the cellular membrane, which is predominantly composed of the lipid bilayer. In this work, multilamellar vesicles (MLV) of phospholipids have been used to shed light on the effect of an IL on the structure of a cellular membrane. The MLVs formed by the zwitterionic lipid, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) are found to shrink as a consequence of interaction with an imidazolium-based IL, 1-decyl-3-methylimidazolium tetrafluoroborate ([DMIM] [BF4]). The absorbed ILs significantly modify the surface charge of the MLVs. While these observations indicate a strong membrane-IL interaction, synchrotron-based small angle X-ray diffraction (SAXD) measurements provide a structural description of the interaction. SAXD and Fourier transform infrared spectroscopy studies clearly reveal a disordering effect of the IL on the conformational organization of the lipid chains. The presence of the negatively charged lipid 1,2-dipalmitoyl-sn-glycero-3-phospho-L-serine sodium salt (DPPS) in MLVs plays an important role in disordering the chains in the membrane and inter-bilayer interactions.

Structural changes in cellular membranes induced by ionic liquids: From model to bacterial membranes.

Ionic liquids (ILs) have generated considerable attention recently because of their cytotoxicity and application as antibiotics. However, the mechanism of how they damage cell membranes is not currently well understood. In this paper, the antibacterial activities of two imidazolium-based ILs, namely 1-butyl- 3-methylimidazolium tetrafluroborate ([BMIM][BF4]) and 1-ethyl- 3-methylimidazolium tetrafluroborate ([EMIM][BF4]) have been investigated. The activity of [BMIM][BF4] on gram negative bacteria E. coli is observed to be stronger compared with the short chained [EMIM][BF4]. To explain this observation, the effects of these ILs on the self-assembled structures of model cellular membranes have been investigated. The in-plane elasticity of a monolayer formed at air-water interface by 1,2-dipalmitoyl- sn-glycero- 3-phosphocholine (DPPC) lipids was reduced in the presence of the ILs. The x-ray reflectivity studies on polymer supported lipid bilayer have shown the bilayer to shrink and correspondingly exhibit an increase in electron density. The presence of a certain mol% of negatively charged lipid, 1,2-dipalmitoyl-rac-glycero-3-phospho-L-serine (DPPS), in DPPC mono- and bi-layers enhances the effect considerably.

Thermodynamics of interaction of ionic liquids with lipid monolayer.

Understanding the interaction of ionic liquids with cellular membrane becomes utterly important to comprehend the activities of these liquids in living organisms. Lipid monolayer formed at the air-water interface is employed as a model system to follow this interaction by investigating important thermodynamic parameters. The penetration kinetics of the imidazolium-based ionic liquid 1-decyl-3-methylimidazolium tetrafluoroborate ([DMIM][BF4]) into the zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid layer is found to follow the Boltzmann-like equation that reveals the characteristic time constant which is observed to be the function of initial surface pressure. The enthalpy and entropy calculated from temperature-dependent pressure-area isotherms of the monolayer show that the added ionic liquids bring about a disordering effect in the lipid film. The change in Gibbs free energy indicates that an ionic liquid with longer chain has a far greater disordering effect compared to an ionic liquid with shorter chain. The differential scanning calorimetric measurement on a multilamellar vesicle system shows the main phase transition temperature to shift to a lower value, which, again, indicates the disordering effect of the ionic liquid on lipid membrane. All these studies fundamentally point out that, when ionic liquids interact with lipid molecules, the self-assembled structure of a cellular membrane gets perturbed, which may be the mechanism of these molecules having adverse effects on living organisms.

X-ray Reflectivity Study of the Interaction of an Imidazolium-Based Ionic Liquid with a Soft Supported Lipid Membrane.

Ionic liquids (ILs) are important for their antimicrobial activity and are found to be toxic to some microorganisms. To shed light on the mechanism of their activities, the interaction of an imidazolium-based IL 1-butyl-3-methylimidazolium tetrfluoroborate ([BMIM][BF4]) with E. coli bacteria and cell-membrane-mimicking lipid mono- and bilayers has been studied. The survival of the bacteria and corresponding growth inhibition are observed to be functions of the concentration of the IL. The IL alters the pressure-area isotherm of the monolayer formed at an air-water interface by the 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid. The in-plane elasticity of the lipid layer is reduced as a consequence of the insertion of this IL. The X-ray reflectivity study from a polymer-supported lipid bilayer shows strong perturbation in the self-assembled structure of the bilayer due to the interaction. As a consequence, there is a considerable decrease in bilayer thickness and a corresponding increase in electron density. These results, however, depend on the chain configurations of the lipid molecules.

Oncology Gold Standard® practical consensus recommendations for the use of monoclonal antibodies in the management of squamous cell carcinoma of head and neck.

We present the 2017 Oncology Gold Standard Practical Consensus Recommendation for use of monoclonal antibodies in the management of advanced squamous cell carcinoma of head neck region.

Isolation and study of insulin activated nitric oxide synthase inhibitory protein in acute myocardial infarction subjects.

Insulin inhibits platelet aggregation through nitric oxide synthesis by stimulating platelet insulin activated nitric oxide synthase. Impaired platelet insulin activated nitric oxide synthase in acute myocardial infarction (AMI) patients had been reported and thus our aim was to identify and isolate the factors impairing insulin activated nitric oxide in acute myocardial infarction patients' plasma and study its effect on platelets aggregation in vitro. The insulin activated nitric oxide synthase inhibitor was identified as a protein and was purified from the plasma of AMI subjects using DEAE cellulose and Sephadex G-50 column, molecular weight determined by SDS-PAGE, nitric oxide quantified by methaemoglobin method, inhibitor protein quantified in plasma by immunoblot and ELISA, platelet aggregation studies done using an aggregometer, thromboxane-A2 in the platelets determined by radioimmunoassay, (125)I-insulin radioligand binding studies done using normal subject platelets. The purified nitric oxide synthase inhibitor protein was ~66 kDa, concentration in AMI subjects' plasma varied from 114 to 9,090 µM and was undetected in normal subjects' plasma. The inhibitor protein competes with insulin for insulin receptor binding sites. The Incubation of the normal subject PRP with 5.0 µM inhibitor for 30 min followed by 0.4 µM ADP addition caused platelet aggregation in vitro, 130 µM aspirin or 400 µU insulin/ml addition was able to abrogate 0.4 µM ADP induced platelet aggregation even in the presence of 5.0 µM inhibitor. A potent inhibitory protein against insulin activated nitric oxide synthase in platelets appears in circulation of AMI subjects impairing nitric oxide production, potentiating ADP induced platelet aggregation and increasing the thromboxane-A2 level in platelets.

Management of primary and metastatic triple negative breast cancer: perceptions of oncologists from India.

BACKGROUND: In order to document the understanding of current evidence for the management of triple negative breast cancer and application of this knowledge in daily practice, we conducted an interactive survey of practicing Indian oncologists. MATERIALS AND METHODS: A core group of academic oncologists devised two hypothetical triple negative cases (metastatic and early breast cancer, respectively) and multiple choice options under different clinical circumstances. The respondents were practicing oncologists in different Indian cities who participated in either an online survey or a meeting. The participants electronically chose their preferred option based on their everyday practice. RESULTS: A total of 152 oncologists participated. Just over half (53.8%) preferred taxane based chemotherapy as first-line chemotherapy in the metastatic setting. In the adjuvant setting, a taxane regimen was chosen by 61%. Over half of respondents (52.6%) underestimated the baseline survival of a patient with node positive triple-negative tumor and 18.9% overestimated this survival compared to the estimate of the Adjuvant! program. DISCUSSION: This data offers insight into the perceptions and practice of a diverse cross-section of practicing oncologists in India with respect to their therapeutic choices in metastatic and adjuvant settings in triple negative breast cancer.

Restoration by aspirin of impaired plasma maspin level in human breast cancer.

Maspin, an anti breast cancer protein, is produced in the normal mammary cells but not in malignant cells in breast cancer. We investigated the effect of aspirin induced increase of plasma nitric oxide (NO) on plasma maspin production in breast cancer patients. Fifteen breast cancer patients (35-65 years), who had not yet undergone any cancer therapy, and an equal number of age matched normal female volunteers participated in the study. They were asked not to take any medication for two weeks. All participants then ingested 150 mg of aspirin. Plasma NO and maspin levels were determined before and at 60 min after the ingestion of aspirin. It was found that the maspin level in plasma increased to 4.63+/-0.02 nM from the basal 0.95+/-0.012 nM (p<0.001) with increase of plasma NO from 0.60+/-0.03 microM to 2.08+/-0.030 microM (p<0.001) in breast cancer patients. In normal volunteers the basal maspin increased from 4.76+/-0.041 to 9.36+/-0.036 nM (p<0.001) with increase of NO from 2.15+/-0.08 to 3.36+/-0.04 microM (p<0.001) at the same period. These results indicated that the ingestion of aspirin might be beneficial for breast cancer through increased maspin production.

The role of insulin dependent NO synthesis in the impaired production of maspin in human breast cancer.

PURPOSE: The synthesis of maspin, a protein with various anti-breast cancer properties has been reported to be produced in normal breast tissue but not in breast cancer cells. We investigated the role of insulin receptors and their upregulation by prostaglandin E(1) in vitro for the stimulation of NO synthesis by the hormone, and its consequence on maspin production in normal neutrophils and malignant cells in breast cancer. METHODS: Maspin and NO were determined by ELISA and methemoglobin method, respectively. RESULTS: The treatment of neutrophils and malignant breast cancer cells with prostaglandin E(1) resulted in partial restoration of the impaired receptor numbers, and resulted in partial normalization of NO and maspin production in these cells compared to normal counterparts. It was not feasible to stimulate NO synthesis to normal ranges by the upregulation of receptor number due to intrinsic decrease of insulin receptors in breast cancer cells. However, aspirin, which was found to stimulate NO synthesis to normal ranges, normalized maspin production in these cells in breast cancer. CONCLUSION: The impaired maspin production was found to be the consequence of impaired insulin induced NO production in breast cancer due to the decrease of insulin receptor binding. Restoration of NO production by aspirin can be useful for the restoration of maspin production in breast cancer.

Synthesis and autoxidation of new tetracyclic 9H,10H-indolizino[1,2-b]indole-1-ones.

The new tetracyclic 9H,10H-indolizino[1,2-b]indole-1-one derivatives (7a-d, 7ea, 7eb) have been synthesized by modified Fischer indole synthesis from the enol ether of 2,5-dihydroxy-7-methyl-6-cyano-indolizine (3) and arylhydrazines (4a-g). Attempted N-methylation of 7a-d produced a series of autoxidized products including 10-hydroperoxy-1-methoxyindolizino[1,2-b]indole (9a-d) as the major product accompanied with methylperoxides (10a-d and 11a-d) and 2-formyl-3-(pyridine-2-yl)indole (12a, 12c) derivatives as the minor products. A plausible mechanism of the autoxidation is postulated based on the isolation of some intermediates. The reaction is thought to proceed through azaenolate/enamine intermediates following a novel type of autoxidation.

The school adjustment of South Asian immigrant children in the United States.

This study examined the school adjustment process among South Asian children who had immigrated to the United States with their parents, and who had below-average grades. Both risk and protective factors for dropping out of school were explored in the context of the traditions, familial values, and social norms of South Asians. Data were collected from 75 parents and 75 children in separate semistructured interviews. Content analysis revealed three major themes: congruence of the parents' and school's views on the value of education, congruence of the parents' and children's beliefs that education is the tool to achieve goals, and determination of the children to achieve goals. The low level of proficiency in English was found to be a critical factor in low achievement and school failure. It was concluded that parental encouragement to succeed, in conjunction with teachers' efforts, can be used to facilitate children's school adjustment. Strategies for assisting immigrant children are discussed.

Knowledge about HIV/AIDS, the perceived risks of infection and sources of information of Asian-Indian adolescents born in the USA.

This study examined the extent and specificity of knowledge about HIV/AIDS, the most used sources of information and the usefulness of these sources among Asian-Indian adolescents who were born in the USA and whose parents emigrated from India. Although 86% knew that having unsafe sex with a person infected with HIV could transmit HIV, 47% did not know that sharing a razor with an HIV-positive person could do so, and a significant proportion believed that donating blood (27%) and taking blood tests (14%) could transmit HIV. Television was the most used source of information, but school programmes on HIV/AIDS were considered the most useful source. The results indicated that to be effective, HIV/AIDS prevention programmes must assess the gap in scientific knowledge and beliefs, and clarify misconceptions, reinforce school programmes to present clear messages about the transmission of HIV/AIDS and utilize television to reach adolescents.

A study of lupus anticoagulant in unexplained fetal wastage.

Lupus Anticoagulant, first discovered in patients of SLE, is now known to be associated with a wide spectrum of diseases. The presence of LA is associated with adverse fetal outcome in an obstetric population. In the present series the incidence of LA was found to be 16.6% and 80% of LA positive subgroup had an unsuccessful outcome.

Peer networks, parental attributes, and drug use among Asian-Indian adolescents born in the United States.

This study examined the interrelationships among peer networks, parental attributes, and drug use among Asian-Indian adolescents born in the United States whose parents emigrated from India. The sample consisted of 200 Asian-Indian adolescents, 116 males and 84 females, aged 13 to 18, who were born in the United States and resided in the greater New York metropolitan area. The subjects were interviewed using a semistructured instrument adapted from relevant validated scales and items from other researchers. Adolescent-reported data were analyzed using descriptive and univariable techniques. Of the 200 subjects, 32.5% had tried some form of tobacco, alcohol, or other drug, and 67.5% did not report drug use of any kind. The adolescents stated whether they had ever (at least one time) smoked cigarettes (16.5%), drank beer (18%), drank wine (20.5%), or smoked marijuana (2.5%). The parents' communication of the harmful consequences of drug use and approval of the adolescents' peer networks correlated (p < .05) independently with less drug use by the adolescents. The parents' concern for education was positively correlated (p < .05) with the adolescents' academic performance. The prevalence of drug use among Asian-Indian adolescents is low. Parents' awareness of their children's school performance, peer networks, and concerns related to the consequences of drug use can be used as an effective mechanism to communicate the prevention of drug use among adolescents.

Drug use among Asian-Indian adolescents: identifying protective/risk factors.

The problem of meeting the normative demands of two cultures (host country and country of origin) has been linked to adolescent substance use as a way to cope with conflicts with parents. This paper examines intergenerational conflict as a precursor to alcohol, tobacco, and other drug use among second-generation Asian-Indian adolescents (Asian Americans whose parents emigrated from India). Based on systems theory, a structural model depicting the linkage and temporal sequelae of mediating factors is presented. Risk and protective factors unique to Asian-Indian adolescents--sociodemographic, family relationship, peer bonding, psychological, cultural, and ecological--are identified. Further, the impact of gender differences on family relationships is examined. Implications of the findings for drug use prevention policies, with special emphasis on developing comprehensive primary prevention strategies, are discussed.

In vitro and in vivo induction of heat shock (stress) protein (Hsp) gene expression by selected pesticides.

The chloroacetamide insecticide alachlor, polyhalogenated cyclic hydrocarbons endrin and chlordane and the organophosphate pesticides chlorpyrifos and fenthion induce oxidative tissue damaging effects including lipid peroxidation and nuclear DNA-single strand breaks. The mechanism involved in the induction of oxidative stress by these xenobiotics is unknown. No information is available regarding whether these pesticides can induce the expression of heat shock (stress) protein (Hsp) genes as a common protective mechanism against tissue damage. The pesticides were administered p.o. individually to female Sprague-Dawley rats in two 0.25 LD50 doses at 0 h and 21 h. The animals were killed at 24 h, and liver, brain, heart and lung tissues were removed to examine the induction of Hsps by Western and Northern blot analysis. In a separate series of experiments, cultured neuroactive PC-12 cells were treated 24 h with 50, 100 or 200 nM concentrations of these pesticides. Alachlor, endrin, chlorpyrifos and fenthion induced Hsp89 alpha and Hsp89 beta in hepatic and brain tissues, as well as in cultured PC-12 cells. Chlordane induced some expression of Hsp89 alpha but not Hsp89 beta in the hepatic and brain tissues of treated rats. Some expression of Hsp89 beta was observed in lung tissues of endrin and alachlor treated animals. These findings were substantiated by Western blot analysis using Hsp90 antibody. Except chlordane all these pesticides induced enhanced synthesis of Hsp90 in cultured PC-12 cells. The results indicate striking tissue differences in the patterns of the Hsps induced by the pesticides which were used, and demonstrate that these pesticides can induce the expression of Hsp89 alpha and Hsp89 beta genes in various target organs of rats. The results support the hypothesis that these genes may be mechanistically involved in protecting tissues against oxidative stress induced by structurally diverse pesticides.

Production of reactive oxygen species by gastric cells in association with Helicobacter pylori.

Reactive oxygen species (ROS) and Helicobacter pylori have been identified as pathogenic factors in several gastrointestinal disorders. Since little information is available regarding the mechanistic pathways of H. pylori-induced gastric injury, the potential role of ROS was investigated. The induction of ROS in gastric cells (GC) by H. pylori was assessed using chemiluminescence, cytochrome c reduction, nitrobluetetrazolium (NBT) reduction and lactate dehydrogenase (LDH) leakage. The dose-dependent protective abilities of selected ROS scavengers on LDH leakage were determined. Following incubation of GC with three strains of H. pylori (1:1), approximately 5.7-8.0 and 3.8-4.3 fold increases were observed in cytochrome c and NBT reduction, respectively, demonstrating production of ROS. Enhanced chemiluminescence responses of 2.1- and 3.7-fold were observed following incubation of GC with H. pylori (ATCC 43504) at ratios of 1:1 and 1:10, respectively. Approximately 2.2- and 3.5-fold increases in LDH leakage were observed at GC:H. pylori (ATCC 43504) ratios of 1:1 and 1:10, respectively. Substantial inhibition of LDH leakage from GC in the presence of H. pylori was observed following co-incubations with selected ROS scavengers with cimetidine serving as the best chemoprotectant. The antioxidants and H2-receptor antagonists had no effect on growth of H. pylori cells. This study demonstrates that H. pylori induces enhanced production of ROS in GC, and enhances membrane damage.