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Results for “Pharmacology and Toxicology”

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At least 19 recordsLinked to original sources

bioRxiv2015

AOP: An R Package For Sufficient Causal Analysis in Pathway-based Screening of Drugs and Chemicals for Adversity

SummaryHow can I quickly find the key events in a pathway that I need to monitor to predict that a/an beneficial/adverse event/outcome will occur? This is a key question when using signaling pathways for drug/chemical screening in pharmacology, toxicology and risk assessment. By identifying these sufficient causal key events, we have fewer events to monitor for a pathway, thereby decreasing assay costs and time, while maximizing the value of the information. I have developed the \"aop\" package which uses back-door analysis of causal networks to identify these minimal sets of key events that are sufficient for making causal predictions.\n\nAvailability and ImplementationThe source for the aop package is available online at Github at https://github.com/DataSciBurgoon/aop and can be installed using the R devtools package. The aop package runs within the R statistical environment. The package has functions that can take pathways (as directed graphs) formatted as a Cytoscape JSON file as input, or pathways can be represented as directed graphs using the R/Bioconductor \"graph\" package. The \"aop\" package has functions that can perform backdoor analysis to identify the minimal set of key events for making causal predictions.\n\nContactlyle.d.burgoon@usace.army.mil

Bioinformatics↗

bioRxiv2017

Chronic intermittent nicotine delivery with lung alveolar region-targeted aerosol technology produces circadian blood pharmacokinetics in rats resembling human smokers

IntroductionCigarette smoke is an aerosol containing microparticles that carry nicotine into lung alveolar region where nicotine is rapidly absorbed into circulation. Nicotine exposure in smokers is a chronic intermittent process, with intake during wakefulness and abstinence during sleep resulting in circadian fluctuation of blood nicotine levels. Here we present a smoking-relevant nicotine exposure device and rodent model.\n\nMethodsWe developed a computer controlled integrated platform where freely moving rodents can be exposed to episodic nicotine aerosol on an investigator-designed schedule. Rats were exposed to nicotine aerosol once every half hr in the dark phase of 12/12-hr dark/light cycles for 10 days. Plasma nicotine and its metabolite cotinine levels were determined with a LC-MS/MS method.\n\nResultsWe characterized the aerosol in the breathing zone of the rodent exposure chamber. The droplet size distribution was within the respirable diameter range. The system can generate a wide range of nicotine concentrations in air that meet a variety of experimental needs. We optimized the parameters of aerosol generation and exposure: plasma nicotine and cotinine concentrations reached 30-35 ng/ml and 190-240 ng/ml, respectively. The nicotine levels and circadian patterns resembled the pharmacokinetic pattern of human smokers.\n\nConclusionsWe developed an aerosol system that can produce chronic intermittent nicotine exposure in unanesthetized and unrestrained rodents with route of administration and circadian blood pharmacokinetics resembling human smokers. This methodology is a novel tool for studies of behavior, pharmacology and toxicology of chronic nicotine exposure, nicotine addiction, tobacco-related diseases, teratogenicity, and for discovery of therapeutics.\n\nImplicationsWe developed a method and an alveolar region-targeted aerosol system that provides chronic intermittent nicotine exposure in rodents. The method produces clinically relevant animal models with the route of administration and circadian pharmacokinetics resembling human smokers. This method is a novel tool for understanding the health effects of chronic nicotine exposures such as with tobacco cigarettes, E-cigarettes and other tobacco products, for studies of pharmacology, toxicology, nicotine addiction, tobacco-related diseases, and for discovery of medications.

pharmacology and toxicology↗

bioRxiv2018

Empirical Models for Anatomical and Physiological Changes in a Human Mother and Fetus During Pregnancy and Gestation

Many parameters treated as constants in traditional physiologically based pharmacokinetic models must be formulated as time-varying quantities when modeling pregnancy and gestation due to the dramatic physiological and anatomical changes that occur during this period. While several collections of empirical models for such parameters have been published, each has shortcomings. We sought to create a repository of empirical models for tissue volumes, blood flow rates, and other quantities that undergo substantial changes in a human mother and her fetus during the time between conception and birth, and to address deficiencies with similar, previously published repositories. We used maximum likelihood estimation to calibrate various models for the time-varying quantities of interest, and then used the Akaike information criterion to select an optimal model for each quantity. For quantities of interest for which time-course data were not available, we constructed composite models using percentages and/or models describing related quantities. In this way, we developed a comprehensive collection of formulae describing parameters essential for constructing a PBPK model of a human mother and her fetus throughout the approximately 40 weeks of pregnancy and gestation. We included models describing blood flow rates through various fetal blood routes that have no counterparts in adults. Our repository of mathematical models for anatomical and physiological quantities of interest provides a basis for PBPK models of human pregnancy and gestation, and as such, it can ultimately be used to support decision-making with respect to optimal pharmacological dosing and risk assessment for pregnant women and their developing fetuses. The views expressed in this article are those of the authors and do not necessarily represent the views or policies of the U.S. Environmental Protection Agency.\n\nAUTHOR SUMMARYPhysiologically based pharmacokinetic modeling is a well-known technique for making predictions about internal time-course concentrations of a substance that has entered an organism. This tool is widely used in both pharmaceutical research and human health risk assessment because it harnesses one of the fundamental tenets of both pharmacology and toxicology: it is the concentrations of an active chemical that reach internal target tissues, rather than externally applied \"doses\", that govern the extent of the response (whether beneficial or adverse). Constructing physiologically based pharmacokinetic models for pregnancy and gestation presents a considerable challenge because many of the required parameters (such as blood flow rates or tissue volumes) that are typically assumed to be constant in adult models or short-duration simulations cannot be assumed to be constant when modeling pregnancy. Here we present models, stated as functions of gestational age, for anatomical and physiological changes that occur in a human mother and fetus during pregnancy and gestation. We evaluated and selected models by applying a consistent statistical technique, and where possible, we compared results produced by our models to those produced by previously-published models. The collection of pregnancy parameter models presented here represents the most comprehensive such collection to date.

developmental biology↗

bioRxiv2018

The QNOAEL vs. BMD for Point of Departure

Quantile bootstrap (QB) methods can be applied to the problem of estimating the No Observed Adverse Effect Level (NOAEL) of a New Molecular Entity (NME) to anticipate a safe starting dose for beginning clinical trials. An estimate of the NOAEL from the extended QB method (called the QNOAEL) can be calculated using multiple disparate studies in the literature and/or from laboratory experiments. The QNOAEL is similar in some ways to the Benchmark Dose (BMD) and is superior to the BMD in others. The Benchmark Dose method is currently widely used in toxicological research.\n\nResults are used in a simulation based on nonparametric cluster analysis methods to calculate confidence levels on the difference between the Effect and the No Effect studies. The QNOAEL simulation generates an intuitive curve that is comparable to the dose-response curve.\n\nThe QNOAEL of ellagic acid (EA) will be calculated for clinical trials of its use as a component therapeutic agent (in BSN476) for treating Chikungunya infections. This will be the first application of QB to the problem of NOAEL estimation for a drug. The specific aims of the proposed study are to evaluate the accuracy and precision of the QB Simulation and QNOAEL compared to the Benchmark Dose Method, and to calculate the QNOAEL of EA for BSN476 Drug Development.

pharmacology and toxicology↗

bioRxiv2018

The AOPOntology: A Semantic Artificial Intelligence Tool for Predictive Toxicology

IntroductionToxicology needs artificial intelligence tools that can automate the prediction of toxicity. Today we are at an interesting nexus. We have thousands of chemicals in the environment that lack regulatory thresholds for determining risk. New high throughput in vitro testing methods are becoming available to test these chemicals. Causal Adverse Outcome Pathway Networks (CAOPN) are emerging that will allow us to make predictions based on perturbations of specific key events within the network. The AOPOntology was developed as infrastructure for this nexus, providing the ability to model and marry the data from the in vitro tests for the thousands of chemicals and place them within the CAOPN framework to facilitate adverse outcome predictions.\n\nMaterials and MethodsThe AOPN is a functional specialized ontology that creates classes that model biological pathways and CAOPNs. Adverse outcome predictions are based on mathematical determinations of key events that are sufficient to infer adverse outcomes will occur, or biological information. These sufficiency relationships are captured in the AOPOntology and used by the semantic reasoners to make predictions.\n\nResultsThe AOPOntology version 1.0 architecture is in place, and a CAOPN for steatosis demonstrates how causal network theory is used to make predictions. The AOPOntology is available at https://github.com/DataSciBurgoon/aop-ontology.\n\nDiscussionThe AOPOntology is a knowledge base for CAOPNs that one can use to make predictions about a chemicals potential toxicity using in vitro high throughput and other assays.\n\nConclusionsUsing CAOPNs and causal network theory one is able to predict potential toxicity for chemicals using in vitro high throughput and various high content screens.

pharmacology and toxicology↗

bioRxiv2017

Early afterdepolarisation tendency as a simulated pro-arrhythmic risk indicator

Drug-induced Torsades de Pointes (TdP) arrhythmia is of major interest in predictive toxicology. Drugs which cause TdP block the hERG cardiac potassium channel. However, not all drugs that block hERG cause TdP. As such, further understanding of the mechanistic route to TdP is needed. Early afterde-polarisations (EADs) are a cell-level phenomenon in which the membrane of a cardiac cell depolarises a second time before repolarisation, and EADs are seen in hearts during TdP. Therefore, we propose a method of predicting TdP using induced EADs combined with multiple ion channel block in simulations using biophysically-based mathematical models of human ventricular cell electrophysiology. EADs were induced in cardiac action potential models using interventions based on diseases that are known to cause EADs, including: increasing the conduction of the L-type calcium channel, decreasing the conduction of the hERG channel, and shifting the inactivation curve of the fast sodium channel. The threshold of intervention that was required to cause an EAD was used to classify drugs into clinical risk categories. The metric that used L-type calcium induced EADs was the most accurate of the EAD metrics at classifying drugs into the correct risk categories, and increased in accuracy when combined with action potential duration measurements. The EAD metrics were all more accurate than hERG block alone, but not as predictive as simpler measures such as simulated action potential duration. This may be because different routes to EADs represent risk well for different patient subgroups, something that is difficult to assess at present.

pharmacology and toxicology↗

bioRxiv2014

Evidences of a cytotoxic activity of S-adenosylmethionine on OCI-AML3 cells

BackgroundThe acute myeloid leukemia (AML) cell line OCI-AML3, carrying both NPM1 mutation A and the heterozygous DNMT3A R882C mutation, represents the model for in vitro studies on AML with mutated NPM11. AML with mutated NPM1 harbours a hypo-methylated profile distinct from those of the other AML subtypes2. This characteristic is probably related to the inhibitory effect of the mutant DNMT3A on the wild type protein3. S-adenosylmethionine (SAM) is a universal methyl donor acting as a coenzyme of DNMT3A. There are growing evidences of the antineoplastic effect of SAM in vitro and in murine models of gastric cancer, colon cancer and hepatocellular carcinoma, where SAM induces the downregulation of several oncogenes4-10. Moreover SAM upregulates the expression of DNMT enzymes in lung cancer cells11. In our knowledge there are no published data exploring the effect of SAM on the growth of OCI-AML3 cells and its ability to modulate DNMT3A activity in this cell line. Study design and methodsThe present data have been generated between August 2013 and April 2014 at the VITROSCREEN facilities in Milan-ITALY. We used a 3-(4,5-dimethylthiazol-2-yl)-2,5-dephenyl tetrazolium bromide (MTT) assay to assess the cytotoxic effect of SAM iodide (Sigma-Aldrich) on OCI-AML3 cells (DSMZ Leibniz Institut). We analyzed then the ability of SAM to induce apoptosis by Tali Image-Based Cytometer (green Annexin V - Alexa Fluor 488 for apoptotic cells, red propidium and green Annexin V-Alexa Fluor 488 for necrotic cells). ResultsThe MTT assays were performed after having treated the OCI-AML3 cells with various concentrations of the indicated drug for 24 hours. We observed no significant effects on cells viability using 0.5M, 10 M and 100 M of SAM (data not shown). In contrast, a dose dependent cytotoxic effect of SAM on OCI-AML3 cells was evident for concentrations equal or superior to 500 M, with an IC50 of 500 M (Figure 1). Since a Cmax of 211(SD 94)M after single intravenous infusion of SAM was previously reported in healthy voluntarees12, we decided to investigate the cytotoxic effect of SAM for concentrations close to 211 M using the MTT test. A significant dose dependent reduction of the cells viability was observed with SAM 200M (62,74% viable cells) and SAM 300M (53.32% viable cells), (Figure 2). The Apoptosis assay after 24 hours of treatment with SAM showed no differences in the percentages of apoptotic cells between the OCI-AML3 cells treated with SAM 300-500-2500 M and the untreated cells (data not shown). After 72 hours, only a minimal effect on the amount of apoptotic cells was obtained, while a clear dose dependent increase in the proportion of dead cells was noted (Figure 3), confirming the results of the aforementioned MTT tests. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/004978v1_fig1.gif" ALT="Figure 1"> View larger version (12K): org.highwire.dtl.DTLVardef@5e4195org.highwire.dtl.DTLVardef@23bd30org.highwire.dtl.DTLVardef@59a9c5org.highwire.dtl.DTLVardef@98e377_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 1.C_FLOATNO MTT assay after 24 h exposure of OCI-AML3 cells to SAM at 0.5 mM, 2.5 mM and 10 mM. CN= negative control, untreated cells. SAM=S-Adenosylmethionine. Percentages of viable cells are reported. Both SAM treated cells and CN were tested in triplicate samples. C_FIG O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=111 SRC="FIGDIR/small/004978v1_fig2.gif" ALT="Figure 2"> View larger version (16K): org.highwire.dtl.DTLVardef@17dab5forg.highwire.dtl.DTLVardef@17e1d00org.highwire.dtl.DTLVardef@a213c5org.highwire.dtl.DTLVardef@c01c13_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 2.C_FLOATNO MTT assay after 24 h exposure of OCI-AML3 cells to SAM at 200 M (0.2mM), 300 M, 400 M, 500 M, 1000 M, 2500M. CN=negative control, untreated cells. SAM=S-Adenosylmethionine. Percentages of viable cells are reported. Both SAM treated cells and CN were tested in triplicate samples. C_FIG O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/004978v1_fig3.gif" ALT="Figure 3"> View larger version (31K): org.highwire.dtl.DTLVardef@733c66org.highwire.dtl.DTLVardef@1825707org.highwire.dtl.DTLVardef@1f99a6org.highwire.dtl.DTLVardef@a08020_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 3.C_FLOATNO Percentages of Living, Dead and Apoptotic OCI-AML3 cells assessed by Tali image based cytometer after 72 hours treatment with different concentrations of SAM, and after 72 hours in medium (CN=negative control). Both SAM treated cells and CN were tested in duplicate samples. C_FIG ConclusionsSAM showed remarkable in vitro cytotoxic activity on OCI-AML3 cells at concentrations similar to those achievable in humans after intravenous administration. SAM is not able to induce apoptosis of OCI-AML3 cells in vitro after 72 hours of treatment. However, the increase in the amount of dead cells after SAM treatment may be due to mechanisms other than apoptosis. In order to verify if the observed cytotoxicity was mediated by the enzymatic activity of DNMT3A, we planned to repeat the cytotoxicity assays after DNMT3A silencing. The in vivo antineoplastic effect of SAM could be assessed in NOD/SCID mice engrafted with OCI-AML3 cells. Authors contributionKAvH wrote the study rationale, designed the study, interpreted the data and wrote the article; IP revised the article, MM and BDS planned and interpreted the experiments and BDS performed the experiments.

Pharmacology and Toxicology↗

bioRxiv2014

Novel Natural Product Discovery from Marine Sponges and their Obligate Symbiotic Organisms

Discovery of novel natural products is an accepted method for the elucidation of pharmacologically active molecules and drug leads. Best known sources for such discovery have been terrestrial plants and microbes, accounting for about 85% of the approved natural products in pharmaceutical use (1), and about 60% of approved pharmaceuticals and new drug applications annually (2). Discovery in the marine environment has lagged due to the difficulty of exploration in this ecological niche. Exploration began in earnest in the 1950s, after technological advances such as scuba diving allowed collection of marine organisms, primarily at a depth to about 15m.\n\nNatural products from filter feeding marine invertebrates and in particular, sponges, have proven to be a rich source of structurally unique pharmacologically active compounds, with over 16,000 molecules isolated thus far (3, 1) and a continuing pace of discovery at hundreds of novel bioactive molecules per year. All classes of pharmaceuticals have been represented in this discovery process, including antiprotazoals, pesticides, TGF-beta inhibitors, cationic channel blockers, anticancer, cytotoxic, antiviral, anti-inflammatory and antibacterial compounds. Important biosynthetic pathways found in sponges which give rise to these compounds include the terpenoid (4), fatty acid, polyketoid, quinone reductase, alkaloid, isoprenoid (5), and non-ribosomal protein synthase pathways.

Pharmacology and Toxicology↗

bioRxiv2015

Rapid quantitative pharmacodynamic imaging with Bayesian estimation

We recently described rapid quantitative pharmacodynamic imaging, a novel method for estimating sensitivity of a biological system to a drug. We tested its accuracy in simulated biological signals with varying receptor sensitivity and varying levels of random noise, and presented initial proof-of-concept data from functional MRI (fMRI) studies in primate brain. However, the initial simulation testing used a simple iterative approach to estimate pharmacokinetic-pharmacodynamic (PKPD) parameters, an approach that was computationally efficient but returned parameters only from a small, discrete set of values chosen a priori.\n\nHere we revisit the simulation testing using a Bayesian method to estimate the PKPD parameters. This improved accuracy compared to our previous method, and noise without intentional signal was never interpreted as signal. We also reanalyze the fMRI proof-of-concept data. The success with the simulated data, and with the limited fMRI data, is a necessary first step toward further testing of rapid quantitative pharmacodynamic imaging.

Pharmacology and Toxicology↗

bioRxiv2015

MDMA impairs response to water intake in healthy volunteers

Hyponatremia is a serious complication of 3,4-methylenedioxymethamphetamine (MDMA) use. We investigated potential mechanisms in two double-blind, placebo-controlled studies. In study 1, healthy drug-experienced volunteers received MDMA or placebo alone and in combination with the alpha-1 adrenergic inverse agonist prazosin, used as a positive control to release antidiuretic hormone (ADH). In study 2, volunteers received MDMA or placebo followed by standardized water intake. MDMA lowered serum sodium, but did not increase ADH or copeptin, although the control prazosin did increase ADH. Water loading reduced serum sodium more after MDMA than after placebo. There was a trend for women to have lower baseline serum sodium than men, but there were no significant interactions with drug condition. Combining studies, MDMA potentiated the ability of water to lower serum sodium. Thus, hyponatremia appears to be a significant risk when hypotonic fluids are consumed during MDMA use. Clinical trials and events where MDMA use is common should anticipate and mitigate this risk.

Pharmacology and Toxicology↗

bioRxiv2015

Effects of MDMA on socioemotional feelings, authenticity, and autobiographical disclosure in healthy volunteers in a controlled setting

The drug 3,4-methylenedioxymethamphetamine (MDMA, \"ecstasy\", \"molly\") is a widely used illicit drug and experimental adjunct to psychotherapy. MDMA has unusual, poorly understood socioemotional effects, including feelings of interpersonal closeness and sociability. To better understand these effects, we conducted a within-subjects double-blind placebo controlled study of the effects of 1.5 mg/kg oral MDMA on social emotions and autobiographical disclosure in a controlled setting. MDMA displayed both sedative- and stimulant-like effects, including increased self-report anxiety. At the same time, MDMA positively altered evaluation of the self (i.e., increasing feelings of authenticity) while decreasing concerns about negative evaluation by others (i.e., decreasing social anxiety). Consistent with these feelings, MDMA increased how comfortable participants felt describing emotional memories. Overall, MDMA produced a prosocial syndrome that seemed to facilitate emotional disclosure and that appears consistent with the suggestion that it represents a novel pharmacological class.

Pharmacology and Toxicology↗

bioRxiv2015

Efficient Generation and Selection of Virtual Populations in Quantitative Systems Pharmacology Models

Quantitative systems pharmacology models mechanistically describe a biological system and the effect of drug treatment on system behavior. Because these models rarely are identifiable from the available data, the uncertainty in physiological parameters may be sampled to create alternative parameterizations of the model, sometimes termed Virtual Patients. In order to reproduce the statistics of a clinical population, Virtual Patients are often weighted to form a Virtual Population that reflects the baseline characteristics of the clinical cohort. Here we introduce a novel technique to efficiently generate Virtual Patients and, from this ensemble, demonstrate how to select a Virtual Population that matches the observed data without the need for weighting. This approach improves confidence in model predictions by mitigating the risk that spurious Virtual Patients become over-represented in Virtual Populations.

Pharmacology and Toxicology↗

bioRxiv2015

Evaluation of antimalarial properties from Azores deep-sea invertebrate extracts: a first contribution

Several deep-sea marine invertebrates were collected from hydrothermal vents, seamounts and cold coral assemblages in the North Atlantic Ocean, near the Azores islands. The effect of their lipid crude extracts against two strains of malaria parasite P. falciparum (Dd2 and 3D7) was measured in vitro in order to establish the potential of these invertebrates as new sources for antimalarial compounds. Extracts that presented higher antimalarial activity potential were gorgonian Callogorgia verticillata and the hydrothermal vent shrimp Mirocaris fortunata, presenting the lowest value of IC50 and the highest selectivity index for both evaluated stains. To our knowledge this is the first report on the antimalarial activity of crude lipid extracts considering species collected at depths higher then 100 m.

Pharmacology and Toxicology↗

bioRxiv2016

Best Practices in Docking and Activity Prediction

During the last decade we witnessed how computational docking methods became a crucial tool in the search for new drug candidates. The central dogma of small molecule docking is that compounds that dock correctly into the receptor are more likely to display biological activity than those that do not dock. This dogma, however, possesses multiple twists and turns that may not be obvious to novice dockers. The first premise is that the compounds must dock; this implies: (i) availability of data, (ii) realistic representation of the chemical entities in a form that can be understood by the computer and the software, and, (iii) exhaustive sampling of the protein-ligand conformational space. The second premise is that, after the sampling, all docking solutions must be ranked correctly with a score representing the physico-chemical foundations of binding. The third premise is that correctness must be defined unambiguously, usually by comparison with static experimental data (or lack thereof). Each of these premises involves some degree of simplification of reality, and overall loss in the accuracy of the docking predictions.\n\nIn this chapter we will revise our latest experiences in receptor-based docking when dealing with all three above-mentioned issues. First, we will explain the theoretical foundation of ICM docking, along with a brief explanation on how we measure performance. Second, we will contextualize ICM by showing its performance in single and multiple receptor conformation schemes with the Directory of Useful Decoys (DUD) and the Pocketome. Third, we will describe which strategies we are using to represent protein plasticity, like using multiple crystallographic structures or Monte Carlo (MC) and Normal Mode Analysis (NMA) sampling methods, emphasizing how to overcome the associated pitfalls (e.g., increased number of false positives). In the last section, we will describe ALiBERO, a new tool that is helping us to improve the discriminative power of X-ray structures and homology models in screening campaigns.

Pharmacology and Toxicology↗

bioRxiv2016

Compound biological signatures facilitate phenotypic screening and target elucidation

We developed a statistical method, BIOSEA, able to identify molecules that are capable of reproducing a desired cellular phenotype, by scanning a large compound collection based on biological similarity. Our method leverages highly incomplete and noisy compound bioactivity signatures from historical high-throughput screening campaigns. We applied our approach in a phenotypic screening workflow and found novel nanomolar inhibitors of cell division that reproduce the mode of action of reference natural products. In a drug discovery setting, our biological hit expansion protocol revealed new inhibitors of the NKCC1 co-transporter for autism spectrum disorders. Furthermore, we demonstrate BIOSEAs capabilities to predict novel targets for old compounds. We report new activities for the drugs nimedipine, fluspirilene and pimozide applicable for compound repurposing and rationalizing drug side effects. Our results highlight the opportunities of reusing public bioactivity data for prospective drug discovery applications where the target or mode of action is not known.

Pharmacology and Toxicology↗

bioRxiv2016

CHITOSAN FROM Portunus Pelagicus IN THE SYNTHESIS OF REDUCED GOLD NANOPARTICLE AS POTENTIAL CARRIER FOR THE DELIVERY OF ERYTHROPOIETIN

Nanotechnology and its promises for clinical translation to targeted drug delivery with limited accompanying toxicity provide exciting research opportunities that demands multidisciplinary approaches. The colloidal metallic systems have been recently investigated in the area of nanomedicine. Gold nanoparticles have found themselves useful for diagnostics and drug delivery applications. In this study, we have reported a novel method for the synthesis of gold nanoparticles using natural, biocompatible and biodegradable chitosan which came from deacetylating chitin from Portunus Pelagicus. It serves many purposes, as a reducing agent, stabilizer and absorption and penetration enhancer.\n\nErythropoietin would have high loading efficiency with chitosan reduced gold nanoparticles; the binding is predominantly through hydrogen bonding. Chitosan reduced gold nanoparticles improve the pharmacodynamics and cellular uptake of Erythropoietin across mucosal sites and have immunoadjuvant properties.\n\nThere is almost 50 % shell waste in crustacean industry. It is resourceful if it would be bioconverted. The process of bioconversion is deproteination, demineralization and deacetylation to obtain chitosan. In synthesizing gold nanoparticles, 1.48 x 10-2 M chloroauric acid will be reduced by heating for 15 minutes in 100mL chitosan solution prepared in 1% acetic acid to yield a ruby-red solution. Erythropoietin would be loaded into it and will undergo 13,000rpm of centrifuge followed by calculating the loading efficiency.

Pharmacology and Toxicology↗

bioRxiv2016

FREEZE DRIED EXTRACTS OF Bidens biternata (Lour.) Merr. And Sheriff. SHOW SIGNIFICANT ANTIDIARRHEAL ACTIVITY IN -VIVO MODELS OF DIARRHEA

Ethnopharmacological relevance of the studyDiarrhea remains one of the main killers of children aged below five years. Traditional antidiarrheal remedies form a potentially viable source of novel low cost efficacious antidiarrheal remedies in low resource settings. There is therefore a pressing to scientifically evaluate these remedies.\n\nAim of the studyThis study aimed to investigate the in vivo and in vitro antidiarrheal activity of Bidens biternata a herb species used in traditional Ayurvedic medicine in the management of diarrhea.\n\nMaterials and MethodsIn the castor oil test twenty (20) adult Sprague-Dawley rats were randomized to the negative control (normal saline), positive control (5 mg/kg loperamide), (200 mg/kg Bidens biternata extract) and (400 mg/kg Bidens biternata extract) groups (n=5 in each group). Castor oil (4 ml/kg) was then administered to the animals one hour after administration of the respective treatments after which the total mass of fecal output excreted after four (4) hours was determined.\n\nIn the charcoal meal test fifteen (15) Sprague Dawley rats were randomized to the negative control (normal saline 5 ml/kg orally), the positive control (atropine sulphate 0.1 mg/kg i.p) and test (400 mg/kg Bidens biternata extract) groups (n=5). Charcoal meal was then administered via oral gavage to each rat thirty (30) minutes after the administration of the various treatments. The distance covered by the charcoal meal from the pylorus was then determined after sacrifice of the animals.\n\nIn the enteropooling test twenty (20) Sprague-Dawley rats were randomized to the negative control (5% v/v ethanol in normal saline), positive control (5 mg/kg loperamide) and test (400 mg/kg Bidens biternata extract) groups and prostaglandin E2 (PGE2) (100g/kg) administered immediately after the treatments. The animals were then sacrificed half an hour later and the volume of the small intestine contents determined. The effects of different concentrations of Bidens biternata extract (0.5. 1.0, 2.0, 3.0 and 5.0 mg/ml) on jejunal contraction were investigated and a dose-response curve constructed using the experimental data after which The ED50 dose determined. The effect of tamsulosin (1 adrenergic blocker), yohimbine (2 adrenergic blocker), propranolol ({beta} adrenergic blocker) and naloxone ( opioid blocker) on the contractile activity of the extract were also investigated.\n\nThe experimental data were expressed as mean {+/-} standard error of mean (SEM) and then analyzed using one way ANOVA followed by Tukeys post hoc test in cases of significance (set at p<0.05).\n\nResultsThe freeze dried extracts of Bidens biternata had significant antidiarrhealeffects in the castor oil induced diarrhea model (p=0.0075) with maximal activity being observed at the 400mg/kg dosage level (1.66{+/-} 0.81g vs. 4.54 {+/-} 0.51 g negative control, p=0.01). Bidens biternata extract had significant effects on intestinal motility in the charcoal meal test compared to the control group (43.61 {+/-} 4.42% vs. 60.54 {+/-} 3.33%: p= 0.02). Bidens biternata extract had a significant effect on PGE2 induced enteropooling (3.06 {+/-} 0.07 ml vs. 4.74 {+/-} 0.10 ml; p<0.001).\n\nThe freeze dried extracts of Bidens biternata had a significant negative effect on the contractility of the isolated rabbit jejunum (p<0.001). The effects of the extract were significantly attenuated by tamsulosin (53.94 {+/-} 4.20% vs. 80.57 {+/-} 4.09%; p=0.0067) and naloxone (53.94 {+/-} 4.20% vs. 73.89 {+/-} 7.26 %; p=0.0358). Yohimbine (p=0.4598) and propranolol (p=0.5966) however did not have any significant effect on the contractile activity of the extract.\n\nConclusionsThe freeze dried extract of Bidens biternata possess significant antidiarrhealactivity in both in vitro and in vivo models which appears to be mediated by modulating both the intestinal motility as well as the secretory activity. The results of this study also validate its traditional use as an antidiarrheal remedy.\n\n\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=196 SRC=\"FIGDIR/small/046185_ufig1.gif\" ALT=\"Figure 1000\">\nView larger version (15K):\norg.highwire.dtl.DTLVardef@1251d73org.highwire.dtl.DTLVardef@1b08654org.highwire.dtl.DTLVardef@430f4forg.highwire.dtl.DTLVardef@a210cc_HPS_FORMAT_FIGEXP M_FIG C_FIG

Pharmacology and Toxicology↗

bioRxiv2016

A Possible Link Between Pyriproxyfen and Microcephaly

The Zika virus is the primary suspect in the large increase in microcephaly cases in 2015-6 in Brazil, however its role is unconfirmed despite individual cases of viral infections found in neural tissue. Here we consider the alternative that the insecticide pyriproxyfen, used in Brazilian drinking water for mosquito control, may actually be the cause. Pyriproxifen is an analog of juvenile hormone, which corresponds in mammals to regulatory molecules including retinoic acid, a vitamin A metabolite, with which it has cross-reactivity and whose application during development causes microcephaly. Methoprene, another juvenile hormone analog approved as an insecticide has metabolites that bind to the retinoid X receptor, and causes developmental disorders in mammals. Isotretinoin is another example of a retinoid causing microcephaly in human babies via activation of the retinoid X receptor. Moreover, tests of pyriproxyfen by the manufacturer, Sumitomo, widely quoted as giving no evidence for developmental toxicity, actually found some evidence for such an effect, including low brain mass and arhinencephaly--incomplete formation of the anterior cerebral hemispheres--in rat pups. Finally, the pyriproxyfen use in Brazil is unprecedented--it has never before been applied to a water supply on such a scale. Claims that it is not being used in Recife, the epicenter of microcephaly cases, do not distinguish the metropolitan area of Recife, where it is widely used, and the municipality, where it is not. Given this combination of information we strongly recommend that the use of pyriproxyfen in Brazil be suspended pending further investigation.

Pharmacology and Toxicology↗