Probabilistic hazard assessment for skin sensitization potency by dose–response modeling using feature elimination instead of quantitative structure–activity relationships

PubMed Central

McKim, James M.; Hartung, Thomas; Kleensang, Andre; Sá-Rocha, Vanessa

2016-01-01

Supervised learning methods promise to improve integrated testing strategies (ITS), but must be adjusted to handle high dimensionality and dose–response data. ITS approaches are currently fueled by the increasing mechanistic understanding of adverse outcome pathways (AOP) and the development of tests reflecting these mechanisms. Simple approaches to combine skin sensitization data sets, such as weight of evidence, fail due to problems in information redundancy and high dimension-ality. The problem is further amplified when potency information (dose/response) of hazards would be estimated. Skin sensitization currently serves as the foster child for AOP and ITS development, as legislative pressures combined with a very good mechanistic understanding of contact dermatitis have led to test development and relatively large high-quality data sets. We curated such a data set and combined a recursive variable selection algorithm to evaluate the information available through in silico, in chemico and in vitro assays. Chemical similarity alone could not cluster chemicals’ potency, and in vitro models consistently ranked high in recursive feature elimination. This allows reducing the number of tests included in an ITS. Next, we analyzed with a hidden Markov model that takes advantage of an intrinsic inter-relationship among the local lymph node assay classes, i.e. the monotonous connection between local lymph node assay and dose. The dose-informed random forest/hidden Markov model was superior to the dose-naive random forest model on all data sets. Although balanced accuracy improvement may seem small, this obscures the actual improvement in misclassifications as the dose-informed hidden Markov model strongly reduced "false-negatives" (i.e. extreme sensitizers as non-sensitizer) on all data sets. PMID:26046447

Probabilistic hazard assessment for skin sensitization potency by dose-response modeling using feature elimination instead of quantitative structure-activity relationships.

PubMed

Luechtefeld, Thomas; Maertens, Alexandra; McKim, James M; Hartung, Thomas; Kleensang, Andre; Sá-Rocha, Vanessa

2015-11-01

Supervised learning methods promise to improve integrated testing strategies (ITS), but must be adjusted to handle high dimensionality and dose-response data. ITS approaches are currently fueled by the increasing mechanistic understanding of adverse outcome pathways (AOP) and the development of tests reflecting these mechanisms. Simple approaches to combine skin sensitization data sets, such as weight of evidence, fail due to problems in information redundancy and high dimensionality. The problem is further amplified when potency information (dose/response) of hazards would be estimated. Skin sensitization currently serves as the foster child for AOP and ITS development, as legislative pressures combined with a very good mechanistic understanding of contact dermatitis have led to test development and relatively large high-quality data sets. We curated such a data set and combined a recursive variable selection algorithm to evaluate the information available through in silico, in chemico and in vitro assays. Chemical similarity alone could not cluster chemicals' potency, and in vitro models consistently ranked high in recursive feature elimination. This allows reducing the number of tests included in an ITS. Next, we analyzed with a hidden Markov model that takes advantage of an intrinsic inter-relationship among the local lymph node assay classes, i.e. the monotonous connection between local lymph node assay and dose. The dose-informed random forest/hidden Markov model was superior to the dose-naive random forest model on all data sets. Although balanced accuracy improvement may seem small, this obscures the actual improvement in misclassifications as the dose-informed hidden Markov model strongly reduced " false-negatives" (i.e. extreme sensitizers as non-sensitizer) on all data sets. Copyright © 2015 John Wiley & Sons, Ltd.

PRELIMINARY ASSESSMENTS OF IN VITRO PHARMACOKINETIC DATA AND EXPOSURE INFORMATION FOR THE TOXCAST PHASE II CHEMICALS

EPA Science Inventory

Momentum has been growing in Toxicology to assess the utility of high-throughput screening (HTS) assays in the determination of chemical testing priorities. However, in vitro potencies determined in these assays do not consider in vivo bioavailability, clearance or exposure estim...

The second international standard for polymyxin B.

PubMed

Lightbown, J W; Thomas, A H; Grab, B; Outschoorn, A S

1973-01-01

Since supplies of the first International Standard for Polymyxin B were exhausted, it was replaced by a second international standard the potency of which was estimated from the results of a collaborative assay carried out by 5 laboratories in 4 countries. The wide variations in the results probably resulted from difficulties experienced in handling the first international standard. The potency finally agreed upon by the collaborating laboratories, on the basis of the overall mean values obtained after rejection of the most discrepant assays, was 8 403 IU/mg. That value was accepted by the WHO Expert Committee on Biological Standardization (1970), which consequently defined the International Unit of polymyxin B as the activity contained in 0.000119 mg of the second international standard.

The second international standard for polymyxin B*

PubMed Central

Lightbown, J. W.; Thomas, A. H.; Grab, B.; Outschoorn, A. S.

1973-01-01

Since supplies of the first International Standard for Polymyxin B were exhausted, it was replaced by a second international standard the potency of which was estimated from the results of a collaborative assay carried out by 5 laboratories in 4 countries. The wide variations in the results probably resulted from difficulties experienced in handling the first international standard. The potency finally agreed upon by the collaborating laboratories, on the basis of the overall mean values obtained after rejection of the most discrepant assays, was 8 403 IU/mg. That value was accepted by the WHO Expert Committee on Biological Standardization (1970), which consequently defined the International Unit of polymyxin B as the activity contained in 0.000119 mg of the second international standard. PMID:4350877

Collaborative study for the establishment of the 4(th) International Standard for Streptomycin.

PubMed

Jorajuria, S; Raphalen, C; Dujardin, V; Daas, A

2015-01-01

An international collaborative study was organised to establish the 4(th) World Health Organization (WHO) International Standard (IS) for Streptomycin. Fourteen laboratories from different countries participated. Potencies of the candidate material were estimated by microbiological assays with sensitive micro-organisms. To ensure continuity between consecutive batches, the 3(rd) IS for Streptomycin was used as a reference. Based on the results of the study, the 4(th) IS for Streptomycin was adopted at the meeting of the WHO Expert Committee for Biological Standardization (ECBS) in 2015 with an assigned potency of 76 000 International Units (IU) per vial. The 4(th) IS for Streptomycin is available from the European Directorate for the Quality of Medicines & HealthCare (EDQM).

A tool for rapid screening of direct DNA agents using reaction rates and relative interaction potency: towards screening environmental contaminants for hazard.

PubMed

Gavina, Jennilee M A; Rubab, Mamoona; Zhang, Huijuan; Zhu, Jiping; Nong, Andy; Feng, Yong-Lai

2011-11-01

DNA damage represents a potential biomarker for determining the exposure risk to chemicals and may provide early warning data for identifying chemical hazards to human health. Here, we have demonstrated a simple chromatography-based method that can be used to rapidly screen for the presence of chemical hazards as well as to determine parameters relevant to hazard assessment. In this proof-of-principle study, a simple in vitro system was used to determine the interaction of pollutants and probable carcinogens, phenyl glycidyl ether (PGE), tetrachlorohydroquinone (Cl(4)HQ), methylmethane sulfonate (MMS), styrene-7,8-oxide (SO), and benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE), a metabolite of benzo[a]pyrene (B[a]P), with single- and double-stranded DNA probes. Differences in potency and reaction kinetics were studied for chemical and DNA type. A relative interaction potency equivalency (PEQ) of a chemical was determined by ratio of interaction potency of a chemical to BPDE as the reference chemical in the reaction with single- and double-stranded oligodeoxynucleotides. PEQs were found to be BPDE > PGE > SO > MMS > Cl(4)HQ for single-stranded oligodeoxynucleotides while they were found to be BPDE > PGE > Cl(4)HQ > MMS > SO for double-stranded oligodeoxynucleotides. Kinetics evaluation revealed that BPDE reacted with both DNA probes at a significantly faster rate, as compared to the remaining test chemicals. Equilibrium was reached within an hour for BPDE, but required a minimum of 48 h for the remaining chemicals. First-order rate constants were (1.61 ± 0.2) × 10(-3) s(-1) and (3.18 ± 0.4) × 10(-4) s(-1) for reaction of BPDE with double- and single-stranded DNA, respectively. The remaining chemicals possessed rate constants from 2 to 13 × 10(-6) s(-1) with a relative kinetic order for reaction with DNA of BPDE ≫ MMS > SO > PGE > Cl(4)HQ for ds-DNA and BPDE ≫ SO ≈ Cl(4)HQ ≈ MMS > PGE for ss-DNA. We further found that the reaction potency, defined by dose-response between chemical pollutants and DNA, depends on the form of DNA present for reaction. Noteworthy, we found that relative PEQ did not follow the same kinetic trends. However, our preliminary findings suggest that reaction kinetics, in combination with relative interaction potency, may be a significant parameter that can be used to evaluate the hazard level of environmental pollutants.

Advances in neglected tropical disease vaccines: Developing relative potency and functional assays for the Na-GST-1/Alhydrogel hookworm vaccine.

PubMed

Brelsford, Jill B; Plieskatt, Jordan L; Yakovleva, Anna; Jariwala, Amar; Keegan, Brian P; Peng, Jin; Xia, Pengjun; Li, Guangzhao; Campbell, Doreen; Periago, Maria Victoria; Correa-Oliveira, Rodrigo; Bottazzi, Maria Elena; Hotez, Peter J; Diemert, David; Bethony, Jeffrey M

2017-02-01

A new generation of vaccines for the neglected tropical diseases (NTDs) have now advanced into clinical development, with the Na-GST-1/Alhydrogel Hookworm Vaccine already being tested in Phase 1 studies in healthy adults. The current manuscript focuses on the often overlooked critical aspects of NTD vaccine product development, more specifically, vaccine stability testing programs. A key measure of vaccine stability testing is "relative potency" or the immunogenicity of the vaccine during storage. As with most NTD vaccines, the Na-GST-1/Alhydrogel Hookworm Vaccine was not developed by attenuation or inactivation of the pathogen (Necator americanus), so conventional methods for measuring relative potency are not relevant for this investigational product. Herein, we describe a novel relative potency testing program and report for the first time on the clinical lot of this NTD vaccine during its first 60 months of storage at 2-8°C. We also describe the development of a complementary functional assay that measures the ability of IgG from animals or humans immunized with Na-GST-1/Alhydrogel to neutralize this important hookworm enzyme. While 90% inhibition of the catalytic activity of Na-GST-1 was achieved in animals immunized with Na-GST-1/Alhydrogel, lower levels of inhibition were observed in immunized humans. Moreover, anti-Na-GST-1 antibodies from volunteers in non-hookworm endemic areas were better able to inhibit catalytic activity than anti-Na-GST-1 antibodies from volunteers resident in hookworm endemic areas. The results described herein provide the critical tools for the product development of NTD vaccines.

Quantitative relationship between the local lymph node assay and human skin sensitization assays.

PubMed

Schneider, K; Akkan, Z

2004-06-01

The local lymph node assay (LLNA) is a new test method which allows for the quantitative assessment of sensitizing potency in the mouse. Here, we investigate the quantitative correlation between results from the LLNA and two human sensitization tests--specifically, human repeat insult patch tests (HRIPTs) and human maximization tests (HMTs). Data for 57 substances were evaluated, of which 46 showed skin sensitizing properties in human tests, whereas 11 yielded negative results in humans. For better comparability data from mouse and human tests were transformed to applied doses per skin area, which ranged over four orders of magnitude for the substances considered. Regression analysis for the 46 human sensitizing substances revealed a significant positive correlation between the LLNA and human tests. The correlation was better between LLNA and HRIPT data (n=23; r=0.77) than between LLNA and HMT data (n=38; r=0.65). The observed scattering of data points is related to various uncertainties, in part associated with insufficiencies of data from older HMT studies. Predominantly negative results in the LLNA for another 11 substances which showed no skin sensitizing activity in human maximization tests further corroborate the correspondence between LLNA and human tests. Based on this analysis, the LLNA can be considered a reliable basis for relative potency assessments for skin sensitizers. Proposals are made for the regulatory exploitation of the LLNA: four potency groups can be established, and assignment of substances to these groups according to the outcome of the LLNA can be used to characterize skin sensitizing potency in substance-specific assessments. Moreover, based on these potency groups, a more adequate consideration of sensitizing substances in preparations becomes possible. It is proposed to replace the current single concentration limit for skin sensitizers in preparations, which leads to an all or nothing classification of a preparation as sensitizing to skin ("R43") in the European Union, by differentiated concentration limits derived from the limits for the four potency groups.

Collective efficacy, group potency, and group performance: meta-analyses of their relationships, and test of a mediation model.

PubMed

Stajkovic, Alexander D; Lee, Dongseop; Nyberg, Anthony J

2009-05-01

The authors examined relationships among collective efficacy, group potency, and group performance. Meta-analytic results (based on 6,128 groups, 31,019 individuals, 118 correlations adjusted for dependence, and 96 studies) reveal that collective efficacy was significantly related to group performance (.35). In the proposed nested 2-level model, collective efficacy assessment (aggregation and group discussion) was tested as the 1st-level moderator. It showed significantly different average correlations with group performance (.32 vs. .45), but the group discussion assessment was homogeneous, whereas the aggregation assessment was heterogeneous. Consequently, there was no 2nd-level moderation for the group discussion, and heterogeneity in the aggregation group was accounted for by the 2nd-level moderator, task interdependence (high, moderate, and low levels were significant; the higher the level, the stronger the relationship). The 2nd and 3rd meta-analyses indicated that group potency was related to group performance (.29) and to collective efficacy (.65). When tested in a structural equation modeling analysis based on meta-analytic findings, collective efficacy fully mediated the relationship between group potency and group performance. The authors suggest future research and convert their findings to a probability of success index to help facilitate practice. (c) 2009 APA, all rights reserved.

Dioxin-like toxic potency in Forster's tern eggs from Green Bay, Lake Michigan, North America

USGS Publications Warehouse

Tillitt, D. E.; Kubiak, T.J.; Ankley, G.T.; Giesy, J.P.

1993-01-01

The endangered Forster's tern (Sternaforsteri) population on Green Bay, Wisconsin has exhibited symptoms of embryotoxicity, congenital deformities, and poor hatching success. The putative causal agents are planar halogenated hydrocarbons (PHH). The objectives of this study were: 1) to evaluate the toxic potency of PHHs in extracts of Forster's tern eggs taken from Green Bay, Lake Michigan and a reference site, Lake Poygan, WI; and 2) to compare the toxic potencies of the egg extracts with the reproductive data available from the same water bird colonies. The relative toxic potency of the egg extracts was assessed with the H4IIE bioassay system to obtain 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQ). The average concentrations of TCDD-EQ in Forster's tern eggs were 214.5 pg/g and 23.4 pg/g from Green Bay and Lake Poygan, respectively. The bioassay results presented here concur with the biological effects and chemical analyses information from other studies on the same Forster's tern colonies.

Time dependent inhibition of xanthine oxidase in irradiated solutions of folic acid, aminopterin and methotrexate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robinson, K.; Pilot, T.F.; Meany, J.E.

1990-01-01

The xanthine oxidase catalyzed oxidation of hypoxanthine was followed by monitoring the formation of uric acid at 290 nm. Inhibition of xanthine oxidase occurs in aqueous solutions of folic acid methotrexate and aminopterin. These compounds are known to dissociate upon exposure to ultraviolet light resulting in the formation of their respective 6-formylpteridine derivatives. The relative rates of dissociation were monitored spectrophotometrically by determining the absorbance of their 2,4-dinitrophenylhydrazine derivatives at 500 nm. When aqueous solutions of folic acid, aminopterin and methotrexate were exposed to uv light, a direct correlation was observed between the concentrations of the 6-formylpteridine derivatives existing inmore » solution and the ability of these solutions to inhibit xanthine oxidase. The relative potency of the respective photolysis products were estimated.« less

Actions of Agonists, Fipronil and Ivermectin on the Predominant In Vivo Splice and Edit Variant (RDLbd, I/V) of the Drosophila GABA Receptor Expressed in Xenopus laevis Oocytes

PubMed Central

Suwanmanee, Siros; Buckingham, Steven David; Biggin, Philip; Sattelle, David

2014-01-01

Ionotropic GABA receptors are the targets for several classes of insecticides. One of the most widely-studied insect GABA receptors is RDL (resistance to dieldrin), originally isolated from Drosophila melanogaster. RDL undergoes alternative splicing and RNA editing, which influence the potency of GABA. Most work has focussed on minority isoforms. Here, we report the first characterisation of the predominant native splice variant and RNA edit, combining functional characterisation with molecular modelling of the agonist-binding region. The relative order of agonist potency is GABA> muscimol> TACA> β-alanine. The I/V edit does not alter the potency of GABA compared to RDLbd. Docking calculations suggest that these agonists bind and activate RDLbdI/V through a similar binding mode. TACA and β-alanine are predicted to bind with lower affinity than GABA, potentially explaining their lower potency, whereas the lower potency of muscimol and isoguvacine cannot be explained structurally from the docking calculations. The A301S (resistance to dieldrin) mutation reduced the potency of antagonists picrotoxin, fipronil and pyrafluprole but the I/V edit had no measurable effect. Ivermectin suppressed responses to GABA of RDLbdI/V, RDLbd and RDLbdI/VA301S. The dieldrin resistant variant also showed reduced sensitivity to Ivermectin. This study of a highly abundant insect GABA receptor isoform will help the design of new insecticides. PMID:24823815

Pre-clinical development of a hydrogen peroxide-inactivated West Nile virus vaccine.

PubMed

Poore, Elizabeth A; Slifka, Dawn K; Raué, Hans-Peter; Thomas, Archana; Hammarlund, Erika; Quintel, Benjamin K; Torrey, Lindsay L; Slifka, Ariel M; Richner, Justin M; Dubois, Melissa E; Johnson, Lawrence P; Diamond, Michael S; Slifka, Mark K; Amanna, Ian J

2017-01-05

West Nile virus (WNV) is a mosquito-transmitted pathogen with a wide geographical range that can lead to long-term disability and death in some cases. Despite the public health risk posed by WNV, including an estimated 3 million infections in the United States alone, no vaccine is available for use in humans. Here, we present a scaled manufacturing approach for production of a hydrogen peroxide-inactivated whole virion WNV vaccine, termed HydroVax-001WNV. Vaccination resulted in robust virus-specific neutralizing antibody responses and protection against WNV-associated mortality in mice or viremia in rhesus macaques (RM). A GLP-compliant toxicology study performed in rats demonstrated an excellent safety profile with clinical findings limited to minor and transient irritation at the injection site. An in vitro relative potency (IVRP) assay was developed and shown to correlate with in vivo responses following forced degradation studies. Long-term in vivo potency comparisons between the intended storage condition (2-8°C) and a thermally stressed condition (40±2°C) demonstrated no loss in vaccine efficacy or protective immunity over a 6-month span of time. Together, the positive pre-clinical findings regarding immunogenicity, safety, and stability indicate that HydroVax-001WNV is a promising vaccine candidate. Copyright © 2016 Elsevier Ltd. All rights reserved.

Potencies of red seabream AHR1- and AHR2-mediated transactivation by dioxins: implication of both AHRs in dioxin toxicity.

PubMed

Bak, Su-Min; Iida, Midori; Hirano, Masashi; Iwata, Hisato; Kim, Eun-Young

2013-03-19

To evaluate species- and isoform-specific responses to dioxins and related compounds (DRCs) via aryl hydrocarbon receptor (AHR) in the red seabream ( Pagrus major ), we constructed a reporter gene assay system. Each expression plasmid of red seabream AHR1 (rsAHR1) and AHR2 (rsAHR2) together with a reporter plasmid containing red seabream CYP1A 5'-flanking region were transfected into COS-7 cells. The cells were treated with graded concentrations of seven DRC congeners including 2,3,7,8-TCDD, 1,2,3,7,8-PeCDD, 1,2,3,4,7,8-HxCDD, 2,3,7,8-TCDF, 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF, and PCB126. Both rsAHR1 and rsAHR2 exhibited dose-dependent responses for all the tested congeners. The rsAHR isoform-specific TCDD induction equivalency factors (rsAHR1- and rsAHR2-IEFs) were calculated on the basis of 2,3,7,8-TCDD relative potency derived from the dose-response of each congener. The rsAHR1-IEFs of PeCDD, HxCDD, TCDF, PeCDF, and HxCDF were estimated as 0.17, 0.29, 2.5, 1.5, and 0.27, respectively. For PCB126, no rsAHR1-IEF was given because of less than 10% 2,3,7,8-TCDD maximum response. The rsAHR2-IEFs of PeCDD, HxCDD, TCDF, PeCDF, HxCDF, and PCB126 were estimated as 0.38, 0.13, 1.5, 0.93, 0.20, and 0.0085, respectively. The rsAHR1/2-IEF profiles were different from WHO toxic equivalency factors for fish. In silico docking simulations supported that both rsAHRs have potentials to bind to these congeners. These results suggest that dioxin toxicities may be mediated by both rsAHRs in red seabreams.

ASSESSMENT OF STANDARD REFERENCE COMPOUNDS FOR COMPARATIVE STUDIES USING THE SALMONELLA TYPHIMURIUM MUTAGENICITY ASSAY: I. WITHOUT EXOGENOUS ACTIVATION

EPA Science Inventory

Finney (1978) described a bioassay as an experiment for estimating the nature, constitution, or potency of a material by means of the eaction that follows its application to living matter. n this paper, two independent laboratories tested 10 known Salmonella mutagens in order to ...

[Cytotoxicity of chemicals used in household products: estimation of eye irritating potency of 25 chemicals tested during 1991-1996].

PubMed

Ikarashi, Y; Tsuchiya, T; Nakamura, A

1997-01-01

Cytotoxicity potential of chemicals was evaluated by determining the concentrations inducing 50% reduction of neutral red (NR) uptake into Chinese hamster fibroblast V79 cells compared with control culture (IC50). The results of cytotoxicity test for surfactants with the data produced by the in vivo Draize eye and skin irritation test were compared. There was a good correlation between cytotoxicity and eye irritation score obtained from the Draize test. In contrast, no correlation was observed between Draize skin irritation score and cytotoxic potential of chemicals. Therefore, the NR cytotoxicity test was regarded as a possible in vitro model for predicting eye irritation. Based on the IC50 values in the NR cytotoxicity test, the eye irritation classification (weak, moderate and strong) for each chemical used in household products has been established. We evaluated the cytotoxicity of 25 chemicals used for antimicrobial, rubber accelerator, rubber antioxidant, ultraviolet absorber etc. in household products, and estimated the eye irritating potency of these test chemicals according to the criterion.

International collaborative studies on potency assays of diphtheria and tetanus toxoids.

PubMed

Van Ramshorst, J D; Sundaresan, T K; Outschoorn, A S

1972-01-01

Collaborative studies showed that relative potency assays for a particular type of diphtheria toxoid (adsorbed) and for tetanus toxoid (plain and adsorbed) gave very similar results, whether the assays were carried out by toxin challenge or by antitoxin titration after immunization of experimental animals with graded doses of toxoid. The same numerical results were obtained with a scoring system as with a system based on survivals only. Although skin tests were used on a very limited scale in these studies, it seems likely that they could replace lethal tests for the diphtheria challenge assays.For both tetanus and diphtheria, the adsorbed toxoid gave a higher relative potency when combined with other antigens than as a single toxoid. Both mice and guinea-pigs were used for the lethal challenge test of adsorbed tetanus toxoid. For the single tetanus toxoid the results were the same, but for the combined toxoid (DPT vaccine) the mouse assay results were about twice those of guinea-pig assays.

International collaborative studies on potency assays of diphtheria and tetanus toxoids

PubMed Central

van Ramshorst, J. D.; Sundaresan, T. K.; Outschoorn, A. S.

1972-01-01

Collaborative studies showed that relative potency assays for a particular type of diphtheria toxoid (adsorbed) and for tetanus toxoid (plain and adsorbed) gave very similar results, whether the assays were carried out by toxin challenge or by antitoxin titration after immunization of experimental animals with graded doses of toxoid. The same numerical results were obtained with a scoring system as with a system based on survivals only. Although skin tests were used on a very limited scale in these studies, it seems likely that they could replace lethal tests for the diphtheria challenge assays. For both tetanus and diphtheria, the adsorbed toxoid gave a higher relative potency when combined with other antigens than as a single toxoid. Both mice and guinea-pigs were used for the lethal challenge test of adsorbed tetanus toxoid. For the single tetanus toxoid the results were the same, but for the combined toxoid (DPT vaccine) the mouse assay results were about twice those of guinea-pig assays. PMID:4537488

Evaluating the Effect of Peptoid Lipophilicity on Antimicrobial Potency, Cytotoxicity, and Combinatorial Library Design.

PubMed

Turkett, Jeremy A; Bicker, Kevin L

2017-04-10

Growing prevalence of antibiotic resistant bacterial infections necessitates novel antimicrobials, which could be rapidly identified from combinatorial libraries. We report the use of the peptoid library agar diffusion (PLAD) assay to screen peptoid libraries against the ESKAPE pathogens, including the optimization of assay conditions for each pathogen. Work presented here focuses on the tailoring of combinatorial peptoid library design through a detailed study of how peptoid lipophilicity relates to antibacterial potency and mammalian cell toxicity. The information gleaned from this optimization was then applied using the aforementioned screening method to examine the relative potency of peptoid libraries against Staphylococcus aureus, Acinetobacter baumannii, and Enterococcus faecalis prior to and following functionalization with long alkyl tails. The data indicate that overall peptoid hydrophobicity and not simply alkyl tail length is strongly correlated with mammalian cell toxicity. Furthermore, this work demonstrates the utility of the PLAD assay in rapidly evaluating the effect of molecular property changes in similar libraries.

Collective autonomy and absenteeism within work teams: a team motivation approach.

PubMed

Rousseau, Vincent; Aubé, Caroline

2013-01-01

This study investigates the role of collective autonomy in regard to team absenteeism by considering team potency as a motivational mediator and task routineness as a moderator. The sample consists of 90 work teams (327 members and 90 immediate superiors) drawn from a public safety organization. Results of structural equation modeling indicate that the relationships between collective autonomy and two indicators of team absenteeism (i.e., absence frequency and time lost) are mediated by team potency. Specifically, collective autonomy is positively related to team potency which in turn is negatively related to team absenteeism. Furthermore, results of hierarchical regression analyses show that task routineness moderates the relationships between collective autonomy and the two indicators of team absenteeism such that these relationships are stronger when the level of task routineness is low. On the whole, this study points out that collective autonomy may exercise a motivational effect on attendance at work within teams, but this effect is contingent on task routineness.

[Toxicity study of cefmatilen hydrochloride hydrate (S-1090) (2)--Single oral dose toxicity study in dogs].

PubMed

Kato, I; Nishimura, K; Ueno, M; Inoue, S; Harihara, A; Yabuuchi, K; Sato, K; Miyauchi, H; Hirata, M; Kimura, Y; Furukawa, H

2001-05-01

Cefmatilen hydrochloride hydrate (S-1090) was administered at 500 and 1000 mg potency/kg once orally to beagle dogs. No deaths occurred. Vomiting, diarrhea or mucous feces occurred on the dosing day, and reddish-brown feces (due to chelated products of S-1090 and its decomposition products with Fe3+ in the diet) were also observed on the dosing and next day. Increases of plasma urea nitrogen and iron were observed on the next day after dosing. No remarkable changes were noted in other examination items. The animals in both groups were considered to be exposed to a similar level of S-1090 based on the toxicokinetic data. The oral lethal dose of S-1090 in dogs was estimated to be more than 1000 mg potency/kg.

Collaborative study for the establishment of the 2(nd) International Standard for Bleomycin Complex A2/B2.

PubMed

Jorajuria, S; Raphalen, C; Dujardin, V; Daas, A

2015-01-01

Organization (WHO) International Standard (IS) for bleomycin complex A2/B2. Eight laboratories from different countries participated. Potencies of the candidate material were estimated by microbiological assays with sensitive micro-organisms. To ensure continuity between consecutive batches, the 1(st) IS for bleomycin complex A2/B2 was used as a reference. Based on the results of the study, the 2(nd) IS for bleomycin complex A2/B2 was adopted at the meeting of the WHO Expert Committee for Biological Standardization (ECBS) in 2014 with an assigned potency of 12 500 International Units (IU) per vial. The 2(nd) IS for bleomycin complex A2/B2 is available from the European Directorate for the Quality of Medicines & HealthCare (EDQM).

Human exposure and risk assessment to airborne pesticides in a rural French community.

PubMed

Coscollà, Clara; López, Antonio; Yahyaoui, Abderrazak; Colin, Patrice; Robin, Corine; Poinsignon, Quentin; Yusà, Vicent

2017-04-15

Outdoor air samples collected during the pesticide agricultural application period (spring and summer) from a rural community in the Centre Region (France) were analyzed to investigate temporal variation of atmospheric pesticide levels (2006-2013) and human inhalation exposure in adults, children and infants. The most frequently detected pesticides were herbicides (trifluralin, pendimethalin), fungicides (chlorothalonil) and insecticides (lindane and α-endosulfan). The three currently-used pesticides most frequently detected presented concentrations ranging from 0.18 to 1128.38ngm -3 ; 0.13 to 117.32ngm -3 and 0.16 to 25.80ngm -3 for chlorothalonil, pendimethalin and trifluralin, respectively. The estimated chronic inhalation risk, expressed as Hazard Quotient (HQ), for adults, children and infants, was <1 for all measured pesticides. Likewise, the cumulative exposure for detected organophosphorus and chloroacetamide pesticides, was estimated using the Relative Potency Factor (RPF) and Hazard Index (HI) as metrics, which was indicated that no risk was observed. The cancer risk classified as likely or possibly carcinogen was estimated to be <8.93 E-05 in infants, for the detected pesticides. Copyright © 2017 Elsevier B.V. All rights reserved.

A functional and thromboelastometric-based micromethod for assessing crotoxin anticoagulant activity and antiserum relative potency against Crotalus durissus terrificus venom.

PubMed

Prezoto, B C; Tanaka-Azevedo, A M; Marcelino, J R; Tashima, A K; Nishiduka, E S; Kapronezai, J; Mota, J O; Rocha, M M T; Serino-Silva, C; Oguiura, N

2018-06-15

The assessment of the capacity of antivenoms to neutralize the lethal activity of snake venoms still relies on traditional rodent in vivo lethality assay. ED 50 and LD 50 assays require large quantities of venoms and antivenoms, and besides leading to animal suffering. Therefore, in vitro tests should be introduced for assessing antivenom neutralizing capacity in intermediary steps of antivenom production. This task is facilitated when one key lethal toxin is identified. A good example is crotoxin, a β-neurotoxin phospholipase A 2 -like toxin that presents anticoagulant activity in vitro and is responsible for the lethality of venoms of Crotalus durissus snakes. By using rotational thromboelastometry, we reported recently one sensitive coagulation assay for assessing relative potency of the anti-bothropic serum in neutralizing procoagulant activity of Bothrops jararaca venom upon recalcified factor-XII-deficient chicken plasma samples (CPS). In this study, we stablished conditions for determining relative potency of four batches of the anti-crotalic serum (ACS) (antagonist) in inactivating crotoxin anticoagulant activity in CPS (target) simultaneously treated with one classical activator of coagulation (agonists). The correlation coefficient (r) between values related the ACS potency in inactivating both in vitro crotoxin anticoagulant activity and the in vivo lethality of whole venom (ED 50 ) was 0.94 (p value < 0.05). In conclusion, slowness in spontaneous thrombin/fibrin generation even after recalcification elicit time lapse sufficient for elaboration of one dose-response curve to pro- or anti-coagulant agonists in CPS. We propose this methodology as an alternative and sensitive assay for assessing antivenom neutralizing ability in plasma of immunized horses as well as for in-process quality control. Copyright © 2018 Elsevier Ltd. All rights reserved.

Maintenance dosing for sublingual immunotherapy by prominent European allergen manufacturers expressed in bioequivalent allergy units.

PubMed

Larenas-Linnemann, Désirée; Esch, Robert; Plunkett, Greg; Brown, Shannon; Maddox, Daniel; Barnes, Charles; Constable, Derek

2011-11-01

Sublingual immunotherapy (SLIT) has become established in Europe, and its efficacy is being evaluated in the United States. The doses used for SLIT in Europe today are difficult to evaluate, because each manufacturer expresses the potency of its extracts differently. To compare in vitro European SLIT maintenance solutions against US licensed standardized allergenic extract concentrates and to determine the monthly SLIT doses delivered expressed in bioequivalent allergy units ([B]AU). We studied Dermatophagoides pteronyssinus, timothy grass pollen, cat (hair) and short ragweed pollen allergen extracts. The SLIT maintenance solutions of 4 leading European manufacturers and standardized concentrate extracts of 3 US manufacturers were analyzed with the following assays: protein content, relative potency (immunoglobulin E [IgE]-binding enzyme-linked immunosorbent assay [ELISA] inhibition) and major allergen content. The relative monthly allergen dose in (B)AU was calculated for each recommended SLIT schedule. Relative potency was approximately 10 times higher for US concentrate standardized extracts-which are meant to be diluted-than for European SLIT maintenance solutions of D pteronyssinus and timothy grass pollen. For cat (hair) and short ragweed pollen, the difference was less. Measurements of relative potency and major allergen content correlated well. In our assays, European mite extracts contain a very low quantity of Der p 2 compared with US mites. Recommended SLIT doses in Europe vary widely among the manufacturers, but are consistently lower (Eur1) or higher (Eur4) over all four allergens tested. SLIT efficacy probably depends on additional factors apart from the exact dose. SLIT dose finding studies should be done for each product. Copyright © 2011 American College of Allergy. Published by Elsevier Inc. All rights reserved.

Advances in neglected tropical disease vaccines: Developing relative potency and functional assays for the Na-GST-1/Alhydrogel hookworm vaccine

PubMed Central

Brelsford, Jill B.; Plieskatt, Jordan L.; Yakovleva, Anna; Jariwala, Amar; Keegan, Brian P.; Peng, Jin; Xia, Pengjun; Li, Guangzhao; Campbell, Doreen; Periago, Maria Victoria; Correa-Oliveira, Rodrigo; Bottazzi, Maria Elena; Hotez, Peter J.

2017-01-01

A new generation of vaccines for the neglected tropical diseases (NTDs) have now advanced into clinical development, with the Na-GST-1/Alhydrogel Hookworm Vaccine already being tested in Phase 1 studies in healthy adults. The current manuscript focuses on the often overlooked critical aspects of NTD vaccine product development, more specifically, vaccine stability testing programs. A key measure of vaccine stability testing is "relative potency" or the immunogenicity of the vaccine during storage. As with most NTD vaccines, the Na-GST-1/Alhydrogel Hookworm Vaccine was not developed by attenuation or inactivation of the pathogen (Necator americanus), so conventional methods for measuring relative potency are not relevant for this investigational product. Herein, we describe a novel relative potency testing program and report for the first time on the clinical lot of this NTD vaccine during its first 60 months of storage at 2–8°C. We also describe the development of a complementary functional assay that measures the ability of IgG from animals or humans immunized with Na-GST-1/Alhydrogel to neutralize this important hookworm enzyme. While 90% inhibition of the catalytic activity of Na-GST-1 was achieved in animals immunized with Na-GST-1/Alhydrogel, lower levels of inhibition were observed in immunized humans. Moreover, anti-Na-GST-1 antibodies from volunteers in non-hookworm endemic areas were better able to inhibit catalytic activity than anti-Na-GST-1 antibodies from volunteers resident in hookworm endemic areas. The results described herein provide the critical tools for the product development of NTD vaccines. PMID:28192438

Hemolysis by surfactants--A review.

PubMed

Manaargadoo-Catin, Magalie; Ali-Cherif, Anaïs; Pougnas, Jean-Luc; Perrin, Catherine

2016-02-01

An overview of the use of surfactants for erythrocyte lysis and their cell membrane action mechanisms is given. Erythrocyte membrane characteristics and its association with the cell cytoskeleton are presented in order to complete understanding of the erythrocyte membrane distortion. Cell homeostasis disturbances caused by surfactants might induce changes starting from shape modification to cell lysis. Two main mechanisms are hypothesized in literature which are osmotic lysis and lysis by solubilization even if the boundary between them is not clearly defined. Another specific mechanism based on the formation of membrane pores is suggested in the particular case of saponins. The lytic potency of a surfactant is related to its affinity for the membrane and the modification of the lipid membrane curvature. This is to be related to the surfactant shape defined by its hydrophobic and hydrophilic moieties but also by experimental conditions. As a consequence, prediction of the hemolytic potency of a given surfactant is challenging. Several studies are focused on the relation between surfactant erythrolytic potency and their physico-chemical parameters such as the critical micellar concentration (CMC), the hydrophile-lipophile balance (HLB), the surfactant membrane/water partition coefficient (K) or the packing parameter (P). The CMC is one of the most important factors considered even if a lytic activity cut-off effect points out that the only consideration of CMC not enough predictive. The relation K.CMC must be considered in addition to the CMC to predict the surfactant lytic capacity within the same family of non ionic surfactant. Those surfactant structure/lytic activity studies demonstrate the requirement to take into account a combination of physico-chemical parameters to understand and foresee surfactant lytic potency. Copyright © 2015 Elsevier B.V. All rights reserved.

Structure-function analysis of amino acid 74 of human RAMP1 and RAMP3 and its role in peptide interactions with adrenomedullin and calcitonin gene-related peptide receptors.

PubMed

Qi, Tao; Ly, Kien; Poyner, David R; Christopoulos, George; Sexton, Patrick M; Hay, Debbie L

2011-05-01

The receptors for calcitonin gene-related peptide (CGRP) and adrenomedullin (AM) are complexes of the calcitonin receptor-like receptor (CLR) and receptor activity-modifying proteins (RAMP). The CGRP receptor is a CLR/RAMP1 pairing whereas CLR/RAMP2 and CLR/RAMP3 constitute two subtypes of AM receptor: AM(1) and AM(2), respectively. Previous studies identified Glu74 in RAMP3 to be important for AM binding and potency. To further understand the importance of this residue and its equivalent in RAMP1 (Trp74) we substituted the native amino acids with several others. In RAMP3, these were Trp, Phe, Tyr, Ala, Ser, Thr, Arg and Asn; in RAMP1, Glu, Phe, Tyr, Ala and Asn substitutions were made. The mutant RAMPs were co-expressed with CLR in Cos7 cells; receptor function in response to AM, AM(2)/intermedin and CGRP was measured in a cAMP assay and cell surface expression was determined by ELISA. Phe reduced AM potency in RAMP3 but had no effect in RAMP1. In contrast, Tyr had no effect in RAMP3 but enhanced AM potency in RAMP1. Most other substitutions had a small effect on AM potency in both receptors whereas there was little impact on CGRP or AM(2) potency. Overall, these data suggest that the geometry and charge of the residue at position 74 contribute to how AM interacts with the AM(2) and CGRP receptors and confirms the role of this position in dictating differential AM pharmacology at the AM(2) and CGRP receptors. Copyright © 2011. Published by Elsevier Inc.

Evaluation of relative potencies for in vitro transactivation of the baikal seal aryl hydrocarbon receptor by dioxin-like compounds.

PubMed

Kim, Eun-Young; Suda, Tomoko; Tanabe, Shinsuke; Batoev, Valeriy B; Petrov, Evgeny A; Iwata, Hisato

2011-02-15

To evaluate the sensitivity and responses to dioxins and related compounds (DRCs) via aryl hydrocarbon receptor (AHR) in Baikal seals (Pusa sibirica), we constructed an in vitro reporter gene assay system. Baikal seal AHR (BS AHR) expression plasmid and a reporter plasmid containing CYP1A1 promoter were transfected in COS-7 cells. The cells were treated with six representative congeners, and dose-dependent responses were obtained for all the congeners. EC50 values of 2,3,7,8-TCDD, 1,2,3,7,8-PeCDD, 2,3,7,8-TCDF, 2,3,4,7,8-PeCDF, and PCB126 were found to be 0.021, 1.8, 0.16, 2.4, and 2.5 nM, respectively. As the response did not reach the maximal plateau, EC50 value for PCB118 could not be obtained. The TCDD-EC50 for BS AHR was as high as that for dioxin sensitive C57BL/6 mouse AHR. The in vitro dose responses were further analyzed following an established systematic framework and multiple (20, 50, and 80%) relative potencies (REPs) to the maximum TCDD response. The estimates revealed lower REP ranges (20-80%) of PeCDD and PeCDF for BS AHR than for mouse AHR. Average of the 20, 50, and 80% REPs was designated as Baikal seal specific TCDD induction equivalency factor (BS IEF). The BS IEFs of PeCDD, TCDF, PeCDF, PCB126, and PCB118 were estimated as 0.010, 0.018, 0.0078, 0.0059, and 0.00010, respectively. Total TCDD induction equivalents (IEQs) that were calculated using BS IEFs and hepatic concentrations in wild Baikal seals corresponded to only 12-31% of 2005 WHO TEF-derived TEQs. Nevertheless, about 50% of Baikal seals accumulated IEQs over the TCDD-EC50 obtained in this study. This assessment was supported by the enhanced CYP1A1 mRNA expression found in 50% of the specimens contaminated over the TCDD-EC50. These findings suggest that the IEFs proposed from this in vitro assay could be used to predict AHR-mediated responses in wild seals.

Design, synthesis and nootropic activity of new analogues of sunifiram and sapunifiram, two potent cognition-enhancers.

PubMed

Martini, Elisabetta; Salvicchi, Alberto; Ghelardini, Carla; Manetti, Dina; Dei, Silvia; Guandalini, Luca; Martelli, Cecilia; Melchiorre, Michele; Cellai, Cristina; Scapecchi, Serena; Teodori, Elisabetta; Romanelli, Maria Novella

2009-11-01

A series of amides and sulfonamides, structurally related to DM235 (sunifiram) and MN19 (sapunifiram), derived by ring expansion or contraction, or by inversion of the exocyclic amide function, have been synthesized and tested for cognition-enhancing activity in the mouse passive-avoidance test. Some of the compounds display good antiamnesic and procognitive activity, with higher potency than piracetam, and with a potency similar to the parent compounds.

Structure-function relations of heparin-mimetic sulfated xylan oligosaccharides: inhibition of human immunodeficiency virus-1 infectivity in vitro.

PubMed

Stone, A L; Melton, D J; Lewis, M S

1998-07-01

Heparins/heparan sulfates modulate the function of proteins and cell membranes in numerous biological systems including normal and disease processes in humans. Heparin has been used for many years as an anticoagulant, and anticoagulant heparin-mimetics were developed several decades ago by chemical sulfation of non-mammalian polysaccharides, e.g., an antithrombotic sulfated xylan. This pharmaceutical, which comprises a mixture of sulfated oligoxylans, also mimics most other biological actions of natural heparins in vitro, including inhibition of the human immunodeficiency virus, but the molecular basis for these actions has been unclear. Here, numerous Components of the sulfated oligoxylan mixture were isolated and when bioassayed in the case of anti-HIV-1 infectivity revealed that a structural specificity underlines the capacity of sulfated xylan to inhibit HIV-1, rather than a non-specific mechanism. Components were isolated by chromatographic fractionation through Bio-Gel P10 in 0.5 M ammonium bicarbonate. This fractionation revealed an elution range associated with apparent molecular weights of approximately 22000 to <1500 relative to standard heparin and heparan sulfates and newly prepared sulfated oligosaccharide standards. Components were characterized by metachromatic absorption spectroscopy, ultracentrifugation, GlcA analysis, and potency against HIV-1 infectivity, both in the tetrazolium cytotoxicity assay and in syncytium-forming assays, in CD4-lymphocytes. Structural specificity was indicated by the differential potencies exhibited by the Components: Highest activity (cytotoxicity) was exhibited by Components in the chromatographic region > or = approximately 5500 in mass (50% effective (inhibitory) concentration = 0.5-0.7 microg ml(-1) in the first fractionation series, and 0.1-0.5 microg ml(-1) in a second series). The potency declined sharply below approximately 5400 in mass, but with an exception; a second structure exhibiting relatively high potency eluted among low-mass oligosaccharides which had an average size of approximately a nonomer. Components displayed differential potencies also against the syncytium-forming infectivity of HIV-1. The high potency against syncytium-formation was retained by Components down to a minimum size of about 4500 in mass, smaller than the > or = approximately 5400 required above. One in ten of the beta1,4-linked xyloses in the native xylan are substituted with a monomeric alpha1,2 DGlcA branch. We have speculated that pharmaceutical actions of sulfated xylan might be related to structures involving the alpha-D linked substituents and this was examined using a space-filling model of a sulfated octaxylan and by analyses of Components for GlcA content. Understanding structure/function relations in the heparin-like actions of these agents would be of general significance for the careful examination of their potential clinical usefulness in many human processes modulated by heparins, including AIDS.

Copper-induced peroxidation of phosphatidylserine-containing liposomes is inhibited by nanomolar concentrations of specific antioxidants.

PubMed

Gal, S; Lichtenberg, D; Bor, A; Pinchuk, I

2007-12-01

Copper-induced peroxidation of liposomal palmitoyllinoleoyl-phosphatidylcholine (PLPC) is inhibited by alpha-tocopherol at micromolar concentrations. In our previous study we found that when the liposomes contain phosphatidylserine (PS), nanomolar concentrations of Toc were sufficient to inhibit peroxidation. In an attempt to gain understanding of the origin of this extreme antioxidative potency, we tested the antioxidative potency of 36 additional antioxidants and the dependence of their potency on the presence of PS in the liposomes. The results of these studies reveal that only 11 of the tested antioxidants possess similar antioxidative potency to that of Toc. These include trolox, butylated hydroxytoluene (BHT), curcumin, nordihydroguaiaretic acid (NDGA), diethylstilbestrol (DES), 2 of the 13 tested flavonoids (luteolin and 7,3',4'-trihydroxyflavone; T-414), alpha-naphthol, 1,5-, 1,6- and 1,7-dihydroxynaphthalenes (DHNs). Propyl gallate (PG), methyl syringate, rosmarinic acid, resveratrol, other flavonoids, as well as beta-naphthol, 1,2-, 1,3-, 1,4-, 2,3-, 2,6-, and 2,7-DHNs were either moderately antioxidative or pro-oxidative. For liposomes made of PLPC (250 microM) and PS (25 microM) the "lag" preceding copper-induced peroxidation (5 microM copper) was doubled upon addition of 30-130nM of the "super-active" antioxidants. We propose that the mechanism responsible for the extreme antioxidative potency against copper-induced peroxidation in PS-containing liposomes involves replenishment of the antioxidant in a ternary PS-copper-antioxidant complex. Based on structure-activity relationship of the 37 tested antioxidants, the "super-antioxidative potency" is attributed to the recycling of relatively stable semiquinone or semiquinone-like radicals.

Do 16 Polycyclic Aromatic Hydrocarbons Represent PAH Air Toxicity?

PubMed Central

Samburova, Vera; Zielinska, Barbara; Khlystov, Andrey

2017-01-01

Estimation of carcinogenic potency based on analysis of 16 polycyclic aromatic hydrocarbons (PAHs) ranked by U.S. Environmental Protection Agency (EPA) is the most popular approach within scientific and environmental air quality management communities. The majority of PAH monitoring projects have been focused on particle-bound PAHs, ignoring the contribution of gas-phase PAHs to the toxicity of PAH mixtures in air samples. In this study, we analyzed the results of 13 projects in which 88 PAHs in both gas and particle phases were collected from different sources (biomass burning, mining operation, and vehicle emissions), as well as in urban air. The aim was to investigate whether 16 particle-bound U.S. EPA priority PAHs adequately represented health risks of inhalation exposure to atmospheric PAH mixtures. PAH concentrations were converted to benzo(a)pyrene-equivalent (BaPeq) toxicity using the toxic equivalency factor (TEF) approach. TEFs of PAH compounds for which such data is not available were estimated using TEFs of close isomers. Total BaPeq toxicities (∑88BaPeq) of gas- and particle-phase PAHs were compared with BaPeq toxicities calculated for the 16 particle-phase EPA PAH (∑16EPABaPeq). The results showed that 16 EPA particle-bound PAHs underrepresented the carcinogenic potency on average by 85.6% relative to the total (gas and particle) BaPeq toxicity of 88 PAHs. Gas-phase PAHs, like methylnaphthalenes, may contribute up to 30% of ∑88BaPeq. Accounting for other individual non-EPA PAHs (i.e., benzo(e)pyrene) and gas-phase PAHs (i.e., naphthalene, 1- and 2-methylnaphthalene) will make the risk assessment of PAH-containing air samples significantly more accurate. PMID:29051449

A pharmacological study of NK1 and NK2 tachykinin receptor characteristics in the rat isolated urinary bladder.

PubMed Central

Hall, J. M.; Flowers, J. M.; Morton, I. K.

1992-01-01

1. We have estimated potencies of tachykinin receptor agonist and antagonist analogues in order to determine the recognition characteristics of tachykinin receptors mediating phasic contractile responses of the rat isolated urinary bladder in vitro. 2. The NK1-selective synthetic agonists, substance P methyl ester and GR73632, the synthetic NK2-selective agonists [beta-Ala8]-NKA(4-10) and GR64349, and the mammalian tachykinins, neurokinin A and neurokinin B, were assayed relative to substance P and were found to be approximately equipotent. The NK3-selective agonist, senktide, was inactive (10 microM). 3. Potencies of all these agonists were not significantly different (P > 0.05) when experiments were carried out in the presence of the neutral endopeptidase inhibitor, phosphoramidon, and the kininase II inhibitor, enalaprilat (both 1 microM). 4. The NK1-selective antagonist, GR82334, inhibited responses to substance P methyl ester in a competitive manner in the rat urinary bladder and the rat ileum, and also in the guinea-pig ileum. Markedly different pKB estimates were obtained in the rat bladder (6.38) and rat ileum (6.56) compared to the guinea-pig ileum (7.42). GR82334 (3 microM) was inactive against responses of the rat bladder to [beta-Ala8]-NKA(4-10). 5. The NK1-selective antagonist (+/-)-CP-96,345 also inhibited responses of the rat bladder and guinea-pig ileum to substance P methyl ester; however, in the rat bladder at 1 microM, this antagonist reversibly inhibited responses both to the NK2-selective agonist [beta-Ala8]-NKA(4-10) and to the muscarinic agonist carbachol (P < or = 0.01), thus showing evidence of some non-selective depressant actions.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1282072

Do 16 Polycyclic Aromatic Hydrocarbons Represent PAH Air Toxicity?

PubMed

Samburova, Vera; Zielinska, Barbara; Khlystov, Andrey

2017-08-15

Estimation of carcinogenic potency based on analysis of 16 polycyclic aromatic hydrocarbons (PAHs) ranked by U.S. Environmental Protection Agency (EPA) is the most popular approach within scientific and environmental air quality management communities. The majority of PAH monitoring projects have been focused on particle-bound PAHs, ignoring the contribution of gas-phase PAHs to the toxicity of PAH mixtures in air samples. In this study, we analyzed the results of 13 projects in which 88 PAHs in both gas and particle phases were collected from different sources (biomass burning, mining operation, and vehicle emissions), as well as in urban air. The aim was to investigate whether 16 particle-bound U.S. EPA priority PAHs adequately represented health risks of inhalation exposure to atmospheric PAH mixtures. PAH concentrations were converted to benzo(a)pyrene-equivalent (BaPeq) toxicity using the toxic equivalency factor (TEF) approach. TEFs of PAH compounds for which such data is not available were estimated using TEFs of close isomers. Total BaPeq toxicities (∑ 88 BaPeq) of gas- and particle-phase PAHs were compared with BaPeq toxicities calculated for the 16 particle-phase EPA PAH (∑ 16EPA BaPeq). The results showed that 16 EPA particle-bound PAHs underrepresented the carcinogenic potency on average by 85.6% relative to the total (gas and particle) BaPeq toxicity of 88 PAHs. Gas-phase PAHs, like methylnaphthalenes, may contribute up to 30% of ∑ 88 BaPeq. Accounting for other individual non-EPA PAHs (i.e., benzo(e)pyrene) and gas-phase PAHs (i.e., naphthalene, 1- and 2-methylnaphthalene) will make the risk assessment of PAH-containing air samples significantly more accurate.

Relationship between potency and boiling point of general anesthetics: a thermodynamic consideration.

PubMed

Dastmalchi, S; Barzegar-Jalali, M

2000-07-20

The most important group of nonspecific drugs is that of the general anesthetics. These nonspecific compounds vary greatly in structure, from noble gases such as Ar or Xe to complex steroids. Since the development of clinical anesthesia over a century ago, there has been a vast amount of research and speculation concerning the mechanism of action of general anesthetics. Despite these efforts, the exact mechanism remains unknown. Many theories of narcosis do not explain how unconsciousness is produced at a molecular level, but instead relate some physicochemical property of anesthetic agents to their anesthetic potencies. In this paper, we address some of those physicochemical properties, with more emphasis on correlating the anesthetic potency of volatile anesthetics to their boiling points based on thermodynamic principles.

Synthetic risks, risk potency, and carcinogen regulation.

PubMed

Viscusi, W K; Hakes, J K

1998-01-01

This article analyzes a comprehensive sample of over 350 chemicals tested for carcinogenicity to assess the determinants of the probability of regulation. Controlling for differences in the risk potency and noncancer risks, synthetic chemicals have a significantly higher probability of regulation overall: this is due to the greater likelihood of U.S. Food and Drug Administration (FDA) regulation. Measures of risk potency increase the probability of regulation by the U.S. Environmental Protection Agency (EPA), have a somewhat weaker positive effect on regulation by the U.S. Occupational Safety and Health Administration (OSHA), and decrease the likelihood of regulation by the FDA. The overall regulatory pattern is one in which the FDA targets synthetic chemicals and chemicals that pose relatively minor cancer risk. The EPA particularly performed more sensibly than many critics have suggested.

Isosteric replacements of the carboxylic acid of drug candidate VX-787: Effect of charge on antiviral potency and kinase activity of azaindole-based influenza PB2 inhibitors.

PubMed

Boyd, Michael J; Bandarage, Upul K; Bennett, Hamilton; Byrn, Randal R; Davies, Ioana; Gu, Wenxin; Jacobs, Marc; Ledeboer, Mark W; Ledford, Brian; Leeman, Joshua R; Perola, Emanuele; Wang, Tiansheng; Bennani, Youssef; Clark, Michael P; Charifson, Paul S

2015-05-01

VX-787 is a first in class, orally bioavailable compound that offers unparalleled potential for the treatment of pandemic and seasonal influenza. As a part of our routine SAR exploration, carboxylic acid isosteres of VX-787 were prepared and tested against influenza A. It was found that the negative charge is important for maintaining potency and selectivity relative to kinase targets. Neutral carboxylic acid replacements generally resulted in compounds that were significantly less potent and less selective relative to the charged species. Copyright © 2015 Elsevier Ltd. All rights reserved.

Leader-team complementarity: Exploring the interactive effects of leader personality traits and team power distance values on team processes and performance.

PubMed

Hu, Jia; Judge, Timothy A

2017-06-01

Integrating the leader trait perspective with dominance complementarity theory, we propose team power distance as an important boundary condition for the indirect impact of leader extraversion, agreeableness, and conscientiousness on team performance through a team's potency beliefs and through relational identification with the leader. Using time-lagged, 3-source data from 71 teams, we found that leader extraversion had a positive indirect impact on team in-role and extrarole performance through relational identification, but only for high power distance teams; leader conscientiousness had a positive influence on team in-role performance through team potency, but only for high power distance teams; and leader agreeableness had a positive effect on team in-role and extrarole performance via relational identification and on team in-role performance via team potency, but only for low power distance teams. The findings address prior inconsistencies regarding the relationships between leader traits and team effectiveness, identify an important boundary condition and key team processes that bridge the links, and provide a deeper understanding of the role of leader traits in teams. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Comprehensive analysis of sexual function outcome in prostate cancer patients after robot-assisted radical prostatectomy.

PubMed

Woo, Seung Hyo; Kang, Dong Il; Ha, Yun-Sok; Salmasi, Amirali Hassanzadeh; Kim, Jeong Hyun; Lee, Dong-Hyeon; Kim, Wun-Jae; Kim, Isaac Yi

2014-02-01

The recovery of potency following radical prostatectomy is complex and has a very wide range. In this study, we analyzed in detail the precise pattern of recovery of potency following robot-assisted radical prostatectomy (RARP). Prospectively collected database of patients with a minimum follow-up of 1 year after RARP were evaluated retrospectively. Of 503 patients identified, 483 patients completed the sexual health inventory for men (SHIM) preoperatively and postoperatively every 3 months for the first 12 months. Overall potency, usage of phosphodiesterase type-5 (PDE-5) inhibitors, and return to baseline erectile function were evaluated. Potency was defined as having erection that is sufficient for sexual intercourse more than 50% of attempts, while quality potency was defined as being potent without the use of PDE-5 inhibitors. Preoperatively, the overall potency and quality potency rate were 67.1% and 48.1%, respectively. Postoperatively, the overall potency rate was 61.4%, while the quality potency rate was 37.2%. In multivariate regression analysis, independent predictors of potency recovery were young age (<60), preoperative potency status, and bilateral preservation of neurovascular bundles (NVBs). In men with SHIM>21, the overall potency and quality potency rate were 79.7% and 41.2%, respectively. More importantly, only 21.4% of the men with normal erection preoperatively (SHIM>21) returned to baseline erectile function (SHIM>21) 12 months after surgery. This study indicates that young age (<60), preoperative potency, and bilateral preservation of NVBs were positive predictors of potency recovery following RARP. However, an overwhelming majority of men experience a deterioration in the overall quality of erection after RARP.

Developmental control of transcriptional and proliferative potency during the evolutionary emergence of animals

PubMed Central

Arenas-Mena, Cesar; Coffman, James A.

2016-01-01

Summary It is proposed that the evolution of complex animals required repressive genetic mechanisms for controlling the transcriptional and proliferative potency of cells. Unicellular organisms are transcriptionally potent, able to express their full genetic complement as the need arises through their life cycle, whereas differentiated cells of multicellular organisms can only express a fraction of their genomic potential. Likewise, whereas cell proliferation in unicellular organisms is primarily limited by nutrient availability, cell proliferation in multicellular organisms is developmentally regulated. Repressive genetic controls limiting the potency of cells at the end of ontogeny would have stabilized the gene expression states of differentiated cells and prevented disruptive proliferation, allowing the emergence of diverse cell types and functional shapes. We propose that distal cis-regulatory elements represent the primary innovations that set the stage for the evolution of developmental gene regulatory networks and the repressive control of key multipotency and cell-cycle control genes. The testable prediction of this model is that the genomes of extant animals, unlike those of our unicellular relatives, encode gene regulatory circuits dedicated to the developmental control of transcriptional and proliferative potency. PMID:26173445

The role of peer respect in linking abusive supervision to follower outcomes: Dual moderation of group potency.

PubMed

Schaubroeck, John M; Peng, Ann C; Hannah, Sean T

2016-02-01

We develop a model in which abusive supervision undermines individuals' perceptions of the level of respect they are accorded by their group peers, which in turn reduces their performance and disconnects them psychologically from the organization. High group potency strengthens each of these connections. We studied the theorized relationships across 3 periods during a 10-week residential organizational entry program. Group potency, representing shared group perceptions, moderated relationships at the individual level. These included the negative relationship between abusive supervision (Time 1) and perceived peer respect (Time 2) and the relationship between perceived peer respect and organizational commitment, organizational identification, and turnover intention (Time 3). We found stronger relationships between abusive supervision and perceived peer respect--and between peer respect and the attitudinal outcomes and turnover intention--among groups with higher potency. Perceived peer respect was also positively related to followers' task performance. We discuss implications of the conceptual framework and findings for future research and theory development concerning how groups and individuals respond to abusive supervision and to treatment by their peers. (c) 2016 APA, all rights reserved).

ANALYSIS OF 2,3,7,8-TCDD TUMOR PROMOTION ACTIVITY AND ITS RELATIONSHIP TO CANCER

EPA Science Inventory

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has a high estimated cancer potency in animals which has been reasoned to imply that TCDD might be carcinogenic to man. The animal cancer data show that TCDD can act in a solitary manner causing tumors without the participation of other ...

[Estimation of the number of minimum salaries attributed to professions in function of their prestige].

PubMed

Sousa, F A; da Silva, J A

2000-04-01

The purpose of this study was to verify the relationship between professional prestige scaled through estimations and the professional prestige scaled through estimation of the number of minimum salaries attributed to professions in function of their prestige in society. Results showed: 1--the relationship between the estimation of magnitudes and the estimation of the number of minimum salaries attributed to the professions in function of their prestige is characterized by a function of potence with an exponent lower than 1,0,2--the orders of degrees of prestige of the professions resultant from different experiments involving different samples of subjects are highly concordant (W = 0.85; p < 0.001), considering the modality used as a number (estimation of magnitudes of minimum salaries).

Structure-Activity Relationships of Substituted Cathinones, with Transporter Binding, Uptake, and Release

PubMed Central

Wolfrum, Katherine M.; Reed, John F.; Kim, Sunyoung O.; Swanson, Tracy; Johnson, Robert A.; Janowsky, Aaron

2017-01-01

Synthetic cathinones are components of “bath salts” and have physical and psychologic side effects, including hypertension, paranoia, and hallucinations. Here, we report interactions of 20 “bath salt” components with human dopamine, serotonin, and norepinephrine transporters [human dopamine transporter (hDAT), human serotonin transporter (hSERT), and human norepinephrine transporter (hNET), respectively] heterologously expressed in human embryonic kidney 293 cells. Transporter inhibitors had nanomolar to micromolar affinities (Ki values) at radioligand binding sites, with relative affinities of hDAT>hNET>hSERT for α-pyrrolidinopropiophenone (α-PPP), α-pyrrolidinobutiophenone, α-pyrrolidinohexiophenone, 1-phenyl-2-(1-pyrrolidinyl)-1-heptanone, 3,4-methylenedioxy-α-pyrrolidinopropiophenone, 3,4-methylenedioxy-α-pyrrolidinobutiophenone, 4-methyl-α-pyrrolidinopropiophenone, α-pyrrolidinovalerophenone, 4-methoxy-α-pyrrolidinovalerophenone, α-pyrrolidinopentiothiophenone (alpha-PVT), and α-methylaminovalerophenone, and hDAT>hSERT>hNET for methylenedioxypentedrone. Increasing the α-carbon chain length increased the affinity and potency of the α-pyrrolidinophenones. Uptake inhibitors had relative potencies of hDAT>hNET>hSERT except α-PPP and α-PVT, which had highest potencies at hNET. They did not induce [3H]neurotransmitter release. Substrates can enter presynaptic neurons via transporters, and the substrates methamphetamine and 3,4-methylenedioxymethylamphetamine are neurotoxic. We determined that 3-fluoro-, 4-bromo-, 4-chloro-methcathinone, and 4-fluoroamphetamine were substrates at all three transporters; 5,6-methylenedioxy-2-aminoindane (MDAI) and 4-methylethcathinone (4-MEC) were substrates primarily at hSERT and hNET; and 3,4-methylenedioxy-N-ethylcathinone (ethylone) and 5-methoxy-methylone were substrates only at hSERT and induced [3H]neurotransmitter release. Significant correlations between potencies for inhibition of uptake and for inducing release were observed for these and additional substrates. The excellent correlation of efficacy at stimulating release versus Ki/IC50 ratios suggested thresholds of binding/uptake ratios above which compounds were likely to be substrates. Based on their potencies at hDAT, most of these compounds have potential for abuse and addiction. 4-Bromomethcathinone, 4-MEC, 5-methoxy-methylone, ethylone, and MDAI, which have higher potencies at hSERT than hDAT, may have empathogen psychoactivity. PMID:27799294

Sacrifice of accessory pudendal arteries in normally potent men during robot-assisted radical prostatectomy does not impact potency.

PubMed

Box, Geoffrey N; Kaplan, Adam G; Rodriguez, Esequiel; Skarecky, Douglas W; Osann, Kathryn E; Finley, David S; Ahlering, Thomas E

2010-01-01

Whether or not sacrificing accessory pudendal arteries (APAs) during radical prostatectomy affects potency has been an ongoing source of concern. Herein, we present our potency results relative to sacrificing APAs in normally pre-potent men following robot-assisted radical prostatectomy (RARP). The distribution of APAs and clinical characteristics were prospectively recorded in 200 consecutive patients undergoing RARP with a cautery-free technique. Sexual function was assessed using the International Index of Erectile Function 5-item questionnaire (IIEF-5). All APAs were sacrificed due to stapling the dorsal vein complex. Postoperatively, potency was defined by an affirmative answer to the following two questions: "Were erections adequate for penetration?" and "were the erections satisfactory?" Postoperative IIEF-5 scores and quality of erections (% of preoperative firmness: 0%, 25%, 50%, 75%, 100%) were also obtained. Subgroup analysis of patients age < or =65 years with IIEF-5 score of 22-25 was performed. Eighty patients (40%) had APAs. Preoperatively, there was no association with having an APA and normal/abnormal sexual function. Preoperatively, 58/200 were < or =65 years with self-administered IIEF-5 scores of 22-25. Postoperatively, 53/58 (91%) were potent at 24 months follow-up. Nineteen of 58 patients had a sacrificed APA; 39 patients had no APA. Eighteen of 19 (95%) patients with sacrificed APAs were potent vs. 35/39 (90%) with no APA present (P = 0.53). Multivariate analysis showed no significant correlation between sacrificing an APA and time of potency recovery, quality of postoperative erections (94% vs. 90% P = 0.80) or mean IIEF-5 score (22.4 vs. 20.8, P = 0.13). We found no correlation between the presence or absence of APAs and preoperative sexual function. Furthermore, after sacrificing all APAs, we found no correlation with potency return, time to return of potency, quality of erections, or mean IIEF-5 scores at 24 months.

High-pressure liquid chromatography analysis of antibiotic susceptibility disks.

PubMed Central

Hagel, R B; Waysek, E H; Cort, W M

1979-01-01

The analysis of antibiotic susceptibility disks by high-pressure liquid chromatography (HPLC) was investigated. Methods are presented for the potency determination of mecillinam, ampicillin, carbenicillin, and cephalothin alone and in various combinations. Good agreement between HPLC and microbiological data is observed for potency determinations with recoveries of greater than 95%. Relative standard deviations of lower than 2% are recorded for each HPLC method. HPLC methods offer improved accuracy and greater precision when compared to the standard microbiological methods of analysis for susceptibility disks. PMID:507793

Relative cancer risks of chemical contaminants in the great lakes

NASA Astrophysics Data System (ADS)

Bro, Kenneth M.; Sonzogni, William C.; Hanson, Mark E.

1987-08-01

Anyone who drinks water or eats fish from the Great Lakes consumes potentially carcinogenic chemicals. In choosing how to respond to such pollution, it is important to put the risks these contaminants pose in perspective. Based on recent measurements of carcinogens in Great Lakes fish and water, calculations of lifetime risks of cancer indicate that consumers of sport fish face cancer risks from Great Lakes contaminants that are several orders of magnitude higher than the risks posed by drinking Great Lakes water. But drinking urban groundwater and breathing urban air may be as hazardous as frequent consumption of sport fish from the Great Lakes. Making such comparisons is difficult because of variation in types and quality of information available and in the methods for estimating risk. Much uncertainty pervades the risk assessment process in such areas as estimating carcinogenic potency and human exposure to contaminants. If risk assessment is to be made more useful, it is important to quantify this uncertainty.

Effect-directed analysis to explore the polar bear exposome: identification of thyroid hormone disrupting compounds in plasma.

PubMed

Simon, Eszter; van Velzen, Martin; Brandsma, Sicco H; Lie, Elisabeth; Løken, Katharina; de Boer, Jacob; Bytingsvik, Jenny; Jenssen, Bjørn M; Aars, Jon; Hamers, Timo; Lamoree, Marja H

2013-08-06

Compounds with transthyretin (TTR)-binding potency in the blood plasma of polar bear cubs were identified with effect-directed analysis (EDA). This approach contributes to the understanding of the thyroid disrupting exposome of polar bears. The selection of these samples for in-depth EDA was based on the difference between the observed TTR-binding potency on the one hand and the calculated potency (based on known concentrations of TTR-binding compounds and their relative potencies) on the other. A library-based identification was applied to the liquid chromatography-time-of-flight-mass spectrometry (LC-ToF-MS) data by screening for matches between compound lists and the LC-ToF-MS data regarding accurate mass and isotope pattern. Then, isotope cluster analysis (ICA) was applied to the LC-ToF-MS data allowing specific screening for halogen isotope patterns. The presence of linear and branched nonylphenol (NP) was observed for the first time in polar bears. Furthermore, the presence of one di- and two monohydroxylated octachlorinated biphenyls (octaCBs) was revealed in the extracts. Linear and branched NP, 4'-OH-CB201 and 4,4'-OH-CB202 could be successfully confirmed with respect to their retention time in the analytical system. In addition, branched NP, mono- and dihydroxylated-octaCBs showed TTR-binding potencies and could explain another 32 ± 2% of the total measured activities in the extracts.

CRISPR/Cas9-mediated gene knockout is insensitive to target copy number but is dependent on guide RNA potency and Cas9/sgRNA threshold expression level

PubMed Central

Yuen, Garmen; Khan, Fehad J.; Gao, Shaojian; Stommel, Jayne M.; Batchelor, Eric; Wu, Xiaolin

2017-01-01

Abstract CRISPR/Cas9 is a powerful gene editing tool for gene knockout studies and functional genomic screens. Successful implementation of CRISPR often requires Cas9 to elicit efficient target knockout in a population of cells. In this study, we investigated the role of several key factors, including variation in target copy number, inherent potency of sgRNA guides, and expression level of Cas9 and sgRNA, in determining CRISPR knockout efficiency. Using isogenic, clonal cell lines with variable copy numbers of an EGFP transgene, we discovered that CRISPR knockout is relatively insensitive to target copy number, but is highly dependent on the potency of the sgRNA guide sequence. Kinetic analysis revealed that most target mutation occurs between 5 and 10 days following Cas9/sgRNA transduction, while sgRNAs with different potencies differ by their knockout time course and by their terminal-phase knockout efficiency. We showed that prolonged, low level expression of Cas9 and sgRNA often fails to elicit target mutation, particularly if the potency of the sgRNA is also low. Our findings provide new insights into the behavior of CRISPR/Cas9 in mammalian cells that could be used for future improvement of this platform. PMID:29036671

CRISPR/Cas9-mediated gene knockout is insensitive to target copy number but is dependent on guide RNA potency and Cas9/sgRNA threshold expression level.

PubMed

Yuen, Garmen; Khan, Fehad J; Gao, Shaojian; Stommel, Jayne M; Batchelor, Eric; Wu, Xiaolin; Luo, Ji

2017-11-16

CRISPR/Cas9 is a powerful gene editing tool for gene knockout studies and functional genomic screens. Successful implementation of CRISPR often requires Cas9 to elicit efficient target knockout in a population of cells. In this study, we investigated the role of several key factors, including variation in target copy number, inherent potency of sgRNA guides, and expression level of Cas9 and sgRNA, in determining CRISPR knockout efficiency. Using isogenic, clonal cell lines with variable copy numbers of an EGFP transgene, we discovered that CRISPR knockout is relatively insensitive to target copy number, but is highly dependent on the potency of the sgRNA guide sequence. Kinetic analysis revealed that most target mutation occurs between 5 and 10 days following Cas9/sgRNA transduction, while sgRNAs with different potencies differ by their knockout time course and by their terminal-phase knockout efficiency. We showed that prolonged, low level expression of Cas9 and sgRNA often fails to elicit target mutation, particularly if the potency of the sgRNA is also low. Our findings provide new insights into the behavior of CRISPR/Cas9 in mammalian cells that could be used for future improvement of this platform. Published by Oxford University Press on behalf of Nucleic Acids Research 2017.

Intermittent Cocaine Self-Administration Produces Sensitization of Stimulant Effects at the Dopamine Transporter

PubMed Central

Calipari, Erin S.; Ferris, Mark J.; Siciliano, Cody A.; Zimmer, Benjamin A.

2014-01-01

Previous literature investigating neurobiological adaptations following cocaine self-administration has shown that high, continuous levels of cocaine intake (long access; LgA) results in reduced potency of cocaine at the dopamine transporter (DAT), whereas an intermittent pattern of cocaine administration (intermittent access; IntA) results in sensitization of cocaine potency at the DAT. Here, we aimed to determine whether these changes are specific to cocaine or translate to other psychostimulants. Psychostimulant potency was assessed by fast-scan cyclic voltammetry in brain slices containing the nucleus accumbens following IntA, short access, and LgA cocaine self-administration, as well as in brain slices from naive animals. We assessed the potency of amphetamine (a releaser), and methylphenidate (a DAT blocker, MPH). MPH was selected because it is functionally similar to cocaine and structurally related to amphetamine. We found that MPH and amphetamine potencies were increased following IntA, whereas neither was changed following LgA or short access cocaine self-administration. Therefore, whereas LgA-induced tolerance at the DAT is specific to cocaine as shown in previous work, the sensitizing effects of IntA apply to cocaine, MPH, and amphetamine. This demonstrates that the pattern with which cocaine is administered is important in determining the neurochemical consequences of not only cocaine effects but potential cross-sensitization/cross-tolerance effects of other psychostimulants as well. PMID:24566123

Comparative In Vitro Toxicity Evaluation of Heavy Metals (Lead, Cadmium, Arsenic, and Methylmercury) on HT-22 Hippocampal Cell Line.

PubMed

Karri, Venkatanaidu; Kumar, Vikas; Ramos, David; Oliveira, Eliandre; Schuhmacher, Marta

2018-07-01

Heavy metals are considered some of the most toxic environmental pollutants. Exposure to heavy metals including lead (Pb), cadmium (Cd), arsenic (As), and methyl mercury (MeHg) has long been known to cause damage to human health. Many recent studies have supported the hippocampus as the major target for these four metals for inflicting cognitive dysfunction. In the present study, we proposed hippocampal relevant in vitro toxicity of Pb, Cd, As, and MeHg in HT-22 cell line. This study reports, initially, cytotoxic effects in acute, subchronic, chronic exposures. We further investigated the mechanistic potency of DNA damage and apoptosis damage with the observed cytotoxicity. The genotoxicity and apoptosis were measured by using the comet assay, annexin-V FTIC / propidium iodide (PI) assay, respectively. The results of cytotoxicity assay clearly demonstrated significant concentration and time-dependent effects on HT-22 cell line. The genotoxic and apoptosis effects also concentration-dependent fashion with respect to their potency in the range of IC 10 -IC 30, maximal level of damage observed in MeHg. In conclusion, the obtained result suggests concentration and potency-dependent response; the maximal level of toxicity was observed in MeHg. These novel findings support that Pb, Cd, As, and MeHg induce cytotoxic, genotoxic, and apoptotic effects on HT-22 cells in potency-dependent manner; MeHg> As> Cd> Pb. Therefore, the toxicity of Pb, Cd, As, and MeHg could be useful for knowing the common underlying molecular mechanism, and also for estimating the mixture impacts on HT-22 cell line.

Apples to apples: the origin and magnitude of differences in asbestos cancer risk estimates derived using varying protocols.

PubMed

Berman, D Wayne

2011-08-01

Given that new protocols for assessing asbestos-related cancer risk have recently been published, questions arise concerning how they compare to the "IRIS" protocol currently used by regulators. The newest protocols incorporate findings from 20 additional years of literature. Thus, differences between the IRIS and newer Berman and Crump protocols are examined to evaluate whether these protocols can be reconciled. Risks estimated by applying these protocols to real exposure data from both laboratory and field studies are also compared to assess the relative health protectiveness of each protocol. The reliability of risks estimated using the two protocols are compared by evaluating the degree with which each potentially reproduces the known epidemiology study risks. Results indicate that the IRIS and Berman and Crump protocols can be reconciled; while environment-specific variation within fiber type is apparently due primarily to size effects (not addressed by IRIS), the 10-fold (average) difference between amphibole asbestos risks estimated using each protocol is attributable to an arbitrary selection of the lowest of available mesothelioma potency factors in the IRIS protocol. Thus, the IRIS protocol may substantially underestimate risk when exposure is primarily to amphibole asbestos. Moreover, while the Berman and Crump protocol is more reliable than the IRIS protocol overall (especially for predicting amphibole risk), evidence is presented suggesting a new fiber-size-related adjustment to the Berman and Crump protocol may ultimately succeed in reconciling the entire epidemiology database. However, additional data need to be developed before the performance of the adjusted protocol can be fully validated. © 2011 Society for Risk Analysis.

Local lymph node assay (LLNA): comparison of different protocols by testing skin-sensitizing epoxy resin system components.

PubMed

Gamer, Armin O; Nies, Eberhard; Vohr, Hans-Werner

2008-12-01

Thirteen epoxy resin system components were tested in the LLNA with regard to their sensitizing potency. Lymph node stimulation was quantified not only by measuring the incorporation of [3H]-thymidine into the ear lymph nodes but also the counts of cells recovered from these organs. Equivalent figures were obtained with both endpoints used for the evaluation of lymph node cell proliferation if the reference stimulation indices were adjusted. When dissolved in acetone, all test substances showed skin-sensitizing potential, mainly on the boundary between "strong" and "moderate" according to common potency evaluation schemes. Replacing acetone with acetone/olive oil (4:1) as a vehicle for four selected test items, resulted in considerably lower estimated concentrations for sensitization induction. The challenges in comparing the results obtained by different LLNA variations are discussed.

Sensory irritating potency of some microbial volatile organic compounds (MVOCs) and a mixture of five MVOCs.

PubMed

Korpi, A; Kasanen, J P; Alarie, Y; Kosma, V M; Pasanen, A L

1999-01-01

The authors investigated the ability/potencies of 3 microbial volatile organic compounds and a mixture of 5 microbial volatile organic compounds to cause eye and upper respiratory tract irritation (i.e., sensory irritation), with an animal bioassay. The authors estimated potencies by determining the concentration capable of decreasing the respiratory frequency of mice by 50% (i.e., the RD50 value). The RD50 values for 1-octen-3-ol, 3-octanol, and 3-octanone were 182 mg/m3 (35 ppm), 1359 mg/m3 (256 ppm), and 17586 mg/m3 (3360 ppm), respectively. Recommended indoor air levels calculated from the individual RD50 values for 1-octen-3-ol, 3-octanol, and 3-octanone were 100, 1000, and 13000 microg/m3, respectively-values considerably higher than the reported measured indoor air levels for these compounds. The RD50 value for a mixture of 5 microbial volatile organic compounds was also determined and found to be 3.6 times lower than estimated from the fractional concentrations and the respective RD50s of the individual components. The data support the conclusion that a variety of microbial volatile organic compounds may have some synergistic effects for the sensory irritation response, which constrains the interpretation and application of recommended indoor air levels of individual microbial volatile organic compounds. The results also showed that if a particular component of a mixture was much more potent than the other components, it may dominate the sensory irritation effect. With respect to irritation symptoms reported in moldy houses, the results of this study indicate that the contribution of microbial volatile organic compounds to these symptoms seems less than previously supposed.

Assessment of pepper spray product potency in Asian and Caucasian forearm skin using transepidermal water loss, skin temperature and reflectance colorimetry.

PubMed

Pershing, Lynn K; Reilly, Christopher A; Corlett, Judy L; Crouch, Dennis J

2006-01-01

Historically, pepper spray product potency has been established using a taste test evaluation. A taste test is subjective and may not be appropriate for assessing pepper potency in skin. The current study evaluated chemically diverse pepper sprays in human forearm skin using three objective, noninvasive parameters: transepidermal water loss, skin surface temperature and erythema, as a means for assessing dermal pharmacology, toxicology and product potency. Five commercial pepper spray products containing various capsaicinoid analogs at various concentrations were evaluated in duplicate on volar forearms of six Caucasians and six Asians using a 10 min exposure. Mean surface skin temperature, transepidermal water loss results were highly variable and therefore did not demonstrate dose responsive behavior to increasing capsaicinoid concentrations. Erythema, as measured by increases in a* (reflected light in the red-to-green color spectrum) of the L*a*b* uniform color scale, was superior among parameters evaluated in discriminating pepper spray potency and correlated well with the relative and total capsaicinoid concentration in the products. Products containing greater than 16 mg ml(-1) capsaicinoid concentration produced greater erythema responses in Caucasians than Asians. Asians responded greater to the synthetic analog, nonivamide, than to mixtures of capsaicinoids, while Caucasians responded equally to both capsaicinoid analogs. Thus, pepper spray product potency in human skin reflects the total capsaicinoid concentration, the specific capsaicin analog(s) present, and the race of the individual exposed. The finding that the reflectance colorimeter a* scale can differentiate these parameters in skin will have a significant impact on evaluating the use and efficacy of pepper spray products in humans. 2005 John Wiley & Sons, Ltd.

Evaluation of Cannabinoid and Terpenoid Content: Cannabis Flower Compared to Supercritical CO2 Concentrate.

PubMed

Sexton, Michelle; Shelton, Kyle; Haley, Pam; West, Mike

2018-03-01

A recent cannabis use survey revealed that 60% of cannabis users rely on smelling the flower to select their cannabis. Olfactory indicators in plants include volatile compounds, principally represented by the terpenoid fraction. Currently, medicinal- and adult-use cannabis is marketed in the United States with relatively little differentiation between products other than by a common name, association with a species type, and Δ-9 tetrahydrocannabinol/cannabidiol potency. Because of this practice, how terpenoid compositions may change during an extraction process is widely overlooked. Here we report on a comparative study of terpenoid and cannabinoid potencies of flower and supercritical fluid CO 2 (SC-CO 2 ) extract from six cannabis chemovars grown in Washington State. To enable this comparison, we employed a validated high-performance liquid chromatography/diode array detector methodology for quantification of seven cannabinoids and developed an internal gas chromatography-mass spectrometry method for quantification of 42 terpenes. The relative potencies of terpenoids and cannabinoids in flower versus concentrate were significantly different. Cannabinoid potency increased by factors of 3.2 for Δ-9 tetrahydrocannabinol and 4.0 for cannabidiol in concentrates compared to flower. Monoterpenes were lost in the extraction process; a ketone increased by 2.2; an ether by 2.7; monoterpene alcohols by 5.3, 7 and 9.4; and sesquiterpenes by 5.1, 4.2, 7.7, and 8.9. Our results demonstrate that the product of SC-CO 2 extraction may have a significantly different chemotypic fingerprint from that of cannabis flower. These results highlight the need for more complete characterization of cannabis and associated products, beyond cannabinoid content, in order to further understand health-related consequences of inhaling or ingesting concentrated forms. Georg Thieme Verlag KG Stuttgart · New York.

Skin sensitization potency and cross-reactivity of p-phenylenediamine and its derivatives evaluated by non-radioactive murine local lymph node assay and guinea-pig maximization test.

PubMed

Yamano, Tetsuo; Shimizu, Mitsuru

2009-04-01

p-Phenylenediamine (PPD)-related chemicals have been used as antioxidants in rubber products, and many cases of contact dermatitis caused by these chemicals have been reported. The aim of this study was to investigate relative sensitizing potency and cross-reactivity among PPD derivatives. Five PPD derivatives, p-aminodiphenylamine (PADPA), N,N'-diphenyl-p-phenylenediamine (DPPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (DMBPPD), N-(1-methylheptyl)-N'-phenyl-p-phenylenediamine (MHPPD), and the core chemical PPD were evaluated for their sensitizing potency and cross-reactivity using the non-radioactive murine local lymph node assay (LLNA) and the guinea-pig maximization test (GPMT). PPD and all the derivatives were identified as primary sensitizers in both tests. The order of potency in the LLNA was as follows: IPPD and PADPA > PPD > DMBPPD and MHPPD > DPPD. In the GPMT, all six groups of animals sensitized with one of these chemicals cross-reacted to four other derivatives. Specifically, the five groups that have a common basic PADPA structure, that is PADPA, DPPD, IPPD, DMBPPD, and MHPPD, all reacted to each other at almost the same scores, while none of them reacted to PPD. The cross-reactivity profile found in the study was to some extent different from that in previous human data, where distinction between cross-reaction and concomitant primary sensitization is not always clear.

Effects of Guideline and Formulary Changes on Statin Prescribing in the Veterans Affairs.

PubMed

Markovitz, Adam A; Holleman, Rob G; Hofer, Timothy P; Kerr, Eve A; Klamerus, Mandi L; Sussman, Jeremy B

2017-12-01

To compare the effects of two sequential policy changes-the addition of a high-potency statin to the Department of Veterans Affairs (VA) formulary and the release of the American College of Cardiology/American Heart Association (ACC/AHA) cholesterol guidelines-on VA provider prescribing. Retrospective analysis of 1,100,682 VA patients, 2011-2016. Interrupted time-series analysis of changes in prescribing of moderate-to-high-intensity statins among high-risk patients and across high-risk subgroups. We also assessed changes in prescribing of atorvastatin and other statin drugs. We estimated marginal effects (ME) of formulary and guideline changes by comparing predicted and observed statin use. Data from VA Corporate Data Warehouse. The use of moderate-to-high-intensity statins increased by 2 percentage points following the formulary change (ME, 2.4, 95% confidence interval [CI], 2.2 to 2.6) and less than 1 percentage point following the guideline change (ME, 0.8, 95% CI, 0.6 to 0.9). The formulary change led to approximately a 12 percentage-point increase in the use of moderate-to-high-intensity atorvastatin (ME, 11.5, 95% CI, 11.3 to 11.6). The relatively greater provider response to the formulary change occurred across all patient subgroups. Addition of a high-potency statin to formulary affected provider prescribing more than the ACC/AHA guidelines. © Health Research and Educational Trust.

Interaction of N-benzoyl-D-phenylalanine and related compounds with the sulphonylurea receptor of beta-cells.

PubMed

Schwanstecher, C; Meyer, M; Schwanstecher, M; Panten, U

1998-03-01

1. The structure activity relationships for the insulin secretagogues N-benzoyl-D-phenylalanine (NBDP) and related compounds were examined at the sulphonylurea receptor level by use of cultured HIT-T15 and mouse pancreatic beta-cells. The affinities of these compounds for the sulphonylurea receptor were compared with their potencies for K(ATP)-channel inhibition. In addition, the effects of cytosolic nucleotides on K(ATP)-channel inhibition by NBDP were investigated. 2. NBDP displayed a dissociation constant for binding to the sulphonylurea receptor (K(D) value) of 11 microM and half-maximally effective concentrations of K(ATP)-channel inhibition (EC50 values) between 2 and 4 microM (in the absence of cytosolic nucleotides or presence of 0.1 mM GDP or 1 mM ADP). 3. In the absence of cytosolic nucleotides or presence of GDP (0.1 mM) maximally effective concentrations of NBDP (0.1-1 mM) reduced K(ATP)-channel activity to 47% and 44% of control, respectively. In the presence of ADP (1 mM), K(ATP)-channel activity was completely suppressed by 0.1 mM NBDP. 4. The L-isomer of N-benzoyl-phenylalanine displayed a 20 fold lower affinity and an 80 fold lower potency than the D-isomer. 5. Introduction of a p-nitro substituent in the D-phenylalanine moiety of NBDP did not decrease lipophilicity but lowered affinity and potency by more than 30 fold. 6. Introduction of a p-amino substituent in the D-phenylalanine moiety of NBDP (N-benzoyl-p-amino-D-phenylalanine, NBADP) reduced lipophilicity and lowered affinity and potency by about 10 fold. This loss of affinity and potency was compensated for by formation of the phenylpropionic acid derivative of NBADP. A similar difference in affinity was observed for the sulphonylurea carbutamide and its phenylpropionic acid derivative. 7. Replacing the benzene ring in the D-phenylalanine moiety of NBDP by a cyclohexyl ring increased lipophilicity, and the K(D) and EC50 values were slightly lower than for NBDP. Exchange of both benzene rings in NBDP by cyclohexyl rings further increased lipophilicity without altering affinity and potency. 8. This study shows that N-acylphenylalanines interact with the sulphonylurea receptor of pancreatic beta-cells in a stereospecific manner. Their potency depends on lipophilic but not aromatic properties of their benzene rings. As observed for sulphonylureas, interaction of N-acylphenylalanines with the sulphonylurea receptor does not induce complete inhibition of K(ATP)-channel activity in the absence of inhibitory cytosolic nucleotides.

Interaction of N-benzoyl-D-phenylalanine and related compounds with the sulphonylurea receptor of β-cells

PubMed Central

Schwanstecher, Christina; Meyer, Miriam; Schwanstecher, Mathias; Panten, Uwe

1998-01-01

The structure activity relationships for the insulin secretagogues N-benzoyl-D-phenylalanine (NBDP) and related compounds were examined at the sulphonylurea receptor level by use of cultured HIT-T15 and mouse pancreatic β-cells. The affinities of these compounds for the sulphonylurea receptor were compared with their potencies for KATP-channel inhibition. In addition, the effects of cytosolic nucleotides on KATP-channel inhibition by NBDP were investigated.NBDP displayed a dissociation constant for binding to the sulphonylurea receptor (KD value) of 11 μM and half-maximally effective concentrations of KATP-channel inhibition (EC50 values) between 2 and 4 μM (in the absence of cytosolic nucleotides or presence of 0.1 mM GDP or 1 mM ADP).In the absence of cytosolic nucleotides or presence of GDP (0.1 mM) maximally effective concentrations of NBDP (0.1–1 mM) reduced KATP-channel activity to 47% and 44% of control, respectively. In the presence of ADP (1 mM), KATP-channel activity was completely suppressed by 0.1 mM NBDP.The L-isomer of N-benzoyl-phenylalanine displayed a 20 fold lower affinity and an 80 fold lower potency than the D-isomer.Introduction of a p-nitro substituent in the D-phenylalanine moiety of NBDP did not decrease lipophilicity but lowered affinity and potency by more than 30 fold.Introduction of a p-amino substituent in the D-phenylalanine moiety of NBDP (N-benzoyl-p-amino-D-phenylalanine, NBADP) reduced lipophilicity and lowered affinity and potency by about 10 fold. This loss of affinity and potency was compensated for by formation of the phenylpropionic acid derivative of NBADP. A similar difference in affinity was observed for the sulphonylurea carbutamide and its phenylpropionic acid derivative.Replacing the benzene ring in the D-phenylalanine moiety of NBDP by a cyclohexyl ring increased lipophilicity, and the KD and EC50 values were slightly lower than for NBDP. Exchange of both benzene rings in NBDP by cyclohexyl rings further increased lipophilicity without altering affinity and potency.This study shows that N-acylphenylalanines interact with the sulphonylurea receptor of pancreatic β-cells in a stereospecific manner. Their potency depends on lipophilic but not aromatic properties of their benzene rings. As observed for sulphonylureas, interaction of N-acylphenylalanines with the sulphonylurea receptor does not induce complete inhibition of KATP-channel activity in the absence of inhibitory cytosolic nucleotides. PMID:9559882

On cancer risk estimation of urban air pollution.

PubMed Central

Törnqvist, M; Ehrenberg, L

1994-01-01

The usefulness of data from various sources for a cancer risk estimation of urban air pollution is discussed. Considering the irreversibility of initiations, a multiplicative model is preferred for solid tumors. As has been concluded for exposure to ionizing radiation, the multiplicative model, in comparison with the additive model, predicts a relatively larger number of cases at high ages, with enhanced underestimation of risks by short follow-up times in disease-epidemiological studies. For related reasons, the extrapolation of risk from animal tests on the basis of daily absorbed dose per kilogram body weight or per square meter surface area without considering differences in life span may lead to an underestimation, and agreements with epidemiologically determined values may be fortuitous. Considering these possibilities, the most likely lifetime risks of cancer death at the average exposure levels in Sweden were estimated for certain pollution fractions or indicator compounds in urban air. The risks amount to approximately 50 deaths per 100,000 for inhaled particulate organic material (POM), with a contribution from ingested POM about three times larger, and alkenes, and butadiene cause 20 deaths, respectively, per 100,000 individuals. Also, benzene and formaldehyde are expected to be associated with considerable risk increments. Comparative potency methods were applied for POM and alkenes. Due to incompleteness of the list of compounds considered and the uncertainties of the above estimates, the total risk calculation from urban air has not been attempted here. PMID:7821292

Cytochrome P4501A induction in avian hepatocyte cultures exposed to polychlorinated biphenyls: Comparisons with AHR1-mediated reporter gene activity and in ovo toxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manning, Gillian E., E-mail: gmann017@uottawa.ca; Environment Canada, National Wildlife Research Centre, Ottawa, ON, Canada K1A 0H3; Mundy, Lukas J., E-mail: lukas.mundy@ec.gc.ca

2013-01-01

Avian-specific toxic equivalency factors (TEFs) were developed by the World Health Organization to simplify environmental risk assessments of dioxin-like compounds (DLCs), but TEFs do not account for differences in the toxic and biochemical potencies of DLCs among species of birds. Such variability may be due to differences in species sensitivity to individual DLCs. The sensitivity of avian species to DLCs was recently associated with the identity of amino acids 324 and 380 in the aryl hydrocarbon receptor 1 (AHR1) ligand binding domain. A luciferase reporter gene (LRG) assay, measuring AHR1-mediated induction of a cytochrome P450 1A5 (CYP1A5) reporter gene, inmore » combination with a species' AHR1 ligand binding domain sequence, were also shown to predict avian species sensitivity to polychlorinated biphenyls (PCBs) and PCB relative potency in a given species. The goals of the present study were to (1) characterize the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and PCBs 126, 77, 105 and 118 on induction of ethoxyresorufin O-deethylase (EROD) activity and CYP1A4/5 mRNA in chicken, ring-necked pheasant and Japanese quail embryo hepatocytes and (2) compare these in vitro results to those previously generated by the LRG assay and in ovo toxicity studies. EROD activity and CYP1A4/5 mRNA expression data support and complement the findings of the LRG assay. CYP1A enzyme activity and mRNA expression were significantly correlated both with luciferase activity and in ovo toxicity induced by PCBs. Relative potency values were generally similar between the LRG and EROD assays and indicate that the relative potency of some PCBs may differ among species. -- Highlights: ► The chicken isn't the most sensitive species to CYP1A induction by PCB 105 and 118. ► The relative potency of PCBs differs between avian species. ► EROD activity was correlated with luciferase activity from the LRG assay. ► EROD activity was a better predictor of toxicity than CYP1A4/5 mRNA expression.« less

Degree of Response to Homeopathic Potencies Correlates with Dipole Moment Size in Molecular Detectors: Implications for Understanding the Fundamental Nature of Serially Diluted and Succussed Solutions.

PubMed

Cartwright, Steven J

2018-02-01

 The use of solvatochromic dyes to investigate homeopathic potencies holds out the promise of understanding the nature of serially succussed and diluted solutions at a fundamental physicochemical level. Recent studies have shown that a range of different dyes interact with potencies and, moreover, the nature of the interaction is beginning to allow certain specific characteristics of potencies to be delineated.  The study reported in this article takes previous investigations further and aims to understand more about the nature of the interaction between potencies and solvatochromic dyes. To this end, the UV-visible spectra of a wide range of potential detectors of potencies have been examined using methodologies previously described.  Results presented demonstrate that solvatochromic dyes are a sub-group of a larger class of compounds capable of demonstrating interactions with potencies. In particular, amino acids containing an aromatic bridge also show marked optical changes in the presence of potencies. Several specific features of molecular detectors can now be shown to be necessary for significant interactions with homeopathic potencies. These include systems with a large dipole moment, electron delocalisation, polarizability and molecular rigidity.  Analysis of the optical changes occurring on interaction with potencies suggests that in all cases potencies increase the polarity of molecular detectors to a degree that correlates with the size of the compound's permanent or ground dipole moment. These results can be explained by inferring that potencies themselves have polarity. Possible candidates for the identity of potencies, based on these and previously reported results, are discussed. The Faculty of Homeopathy.

Progestin and estrogen potency of combination oral contraceptives and endometrial cancer risk.

PubMed

Maxwell, G L; Schildkraut, J M; Calingaert, B; Risinger, J I; Dainty, L; Marchbanks, P A; Berchuck, A; Barrett, J C; Rodriguez, G C

2006-11-01

Using data from a case-control study of endometrial cancer, we investigated the relationship between the progestin and estrogen potency in combination oral contraceptives (OCs) and the risk of developing endometrial cancer. Subjects included 434 endometrial cancer cases and 2,557 controls identified from the Cancer and Steroid Hormone (CASH) study. OCs were classified into four categories according to the individual potencies of each hormonal constituent (high versus low estrogen or progestin potency). Logistic regression was used to evaluate associations between endometrial cancer risk and combination OC formulations. With non-users as the referent group, use of OCs with either high potency progestin [odds ratio for endometrial cancer (OR)=0.21, 95% confidence interval (CI)=0.10 to 0.43] or with low potency progestin (OR=0.39, 95% CI=0.25 to 0.60) were both associated with a decreased risk of endometrial cancer. Overall high progestin potency OCs did not confer significantly more protection than low progestin potency OCs (OR=0.52, 95% CI=0.24 to 1.14). However, among women with a body mass index of 22.1 kg/m2 or higher, those who used high progestin potency oral contraceptives had a lower risk of endometrial cancer than those who used low progestin potency oral contraceptives (OR=0.31, 95% CI=0.11 to 0.92) while those with a BMI below 22.1 kg/m2 did not (OR=1.36, 95% CI=0.39 to 4.70). The potency of the progestin in most OCs appears adequate to provide a protective effect against endometrial cancer. Higher progestin-potency OCs may be more protective than lower progestin potency OCs among women with a larger body habitus.

Prediction of cyclin-dependent kinase 2 inhibitor potency using the fragment molecular orbital method

PubMed Central

2011-01-01

Background The reliable and robust estimation of ligand binding affinity continues to be a challenge in drug design. Many current methods rely on molecular mechanics (MM) calculations which do not fully explain complex molecular interactions. Full quantum mechanical (QM) computation of the electronic state of protein-ligand complexes has recently become possible by the latest advances in the development of linear-scaling QM methods such as the ab initio fragment molecular orbital (FMO) method. This approximate molecular orbital method is sufficiently fast that it can be incorporated into the development cycle during structure-based drug design for the reliable estimation of ligand binding affinity. Additionally, the FMO method can be combined with approximations for entropy and solvation to make it applicable for binding affinity prediction for a broad range of target and chemotypes. Results We applied this method to examine the binding affinity for a series of published cyclin-dependent kinase 2 (CDK2) inhibitors. We calculated the binding affinity for 28 CDK2 inhibitors using the ab initio FMO method based on a number of X-ray crystal structures. The sum of the pair interaction energies (PIE) was calculated and used to explain the gas-phase enthalpic contribution to binding. The correlation of the ligand potencies to the protein-ligand interaction energies gained from FMO was examined and was seen to give a good correlation which outperformed three MM force field based scoring functions used to appoximate the free energy of binding. Although the FMO calculation allows for the enthalpic component of binding interactions to be understood at the quantum level, as it is an in vacuo single point calculation, the entropic component and solvation terms are neglected. For this reason a more accurate and predictive estimate for binding free energy was desired. Therefore, additional terms used to describe the protein-ligand interactions were then calculated to improve the correlation of the FMO derived values to experimental free energies of binding. These terms were used to account for the polar and non-polar solvation of the molecule estimated by the Poisson-Boltzmann equation and the solvent accessible surface area (SASA), respectively, as well as a correction term for ligand entropy. A quantitative structure-activity relationship (QSAR) model obtained by Partial Least Squares projection to latent structures (PLS) analysis of the ligand potencies and the calculated terms showed a strong correlation (r2 = 0.939, q2 = 0.896) for the 14 molecule test set which had a Pearson rank order correlation of 0.97. A training set of a further 14 molecules was well predicted (r2 = 0.842), and could be used to obtain meaningful estimations of the binding free energy. Conclusions Our results show that binding energies calculated with the FMO method correlate well with published data. Analysis of the terms used to derive the FMO energies adds greater understanding to the binding interactions than can be gained by MM methods. Combining this information with additional terms and creating a scaled model to describe the data results in more accurate predictions of ligand potencies than the absolute values obtained by FMO alone. PMID:21219630

Chemical applicability domain of the local lymph node assay (LLNA) for skin sensitisation potency. Part 4. Quantitative correlation of LLNA potency with human potency.

PubMed

Roberts, David W; Api, Anne Marie

2018-07-01

Prediction of skin sensitisation potential and potency by non-animal methods is the target of many active research programmes. Although the aim is to predict sensitisation potential and potency in humans, data from the murine local lymph node assay (LLNA) constitute much the largest source of quantitative data on in vivo skin sensitisation. The LLNA has been the preferred in vivo method for identification of skin sensitising chemicals and as such is potentially valuable as a benchmark for assessment of non-animal approaches. However, in common with all predictive test methods, the LLNA is subject to false positives and false negatives with an overall level of accuracy said variously to be approximately 80% or 90%. It is also necessary to consider the extent to which, for true positives, LLNA potency correlates with human potency. In this paper LLNA potency and human potency are compared so as to express quantitatively the correlation between them, and reasons for non-agreement between LLNA and human potency are analysed. This leads to a better definition of the applicability domain of the LLNA, within which LLNA data can be used confidently to predict human potency and as a benchmark to assess the performance of non-animal approaches. Copyright © 2018. Published by Elsevier Inc.

The murine local lymph node assay: regulatory and potency considerations under REACH.

PubMed

McGarry, Helen F

2007-09-05

From June 2007, new chemicals legislation on the registration, evaluation, authorization and restriction of chemicals (REACH) will come into force across the European Union. This will require the submission of data on human health effects of chemicals, including chemical safety assessments which will require measurements of potency. For skin sensitization hazard identification, REACH states that the first-choice in vivo assay is the local lymph node assay (LLNA). This test has also been the UK competent authority's preferred test for skin sensitization since 2002, and has now replaced guinea pig tests in dossiers submitted to it under the Notification of New Substances Regulations. Advantages of the LLNA over guinea pig tests include improvements in animal welfare, a more scientific approach to hazard identification, and the inclusion of a dose-response element in the endpoint, which enables an estimation of potency. However, notifiers to the UK competent authority have sometimes been reluctant to use the assay because of concerns over false-positive reactions. Across Europe, these concerns have been heightened in the lead-up to the introduction of REACH, since the use of in vivo alternatives to the LLNA will require scientific justification. This review will address some of these concerns from a regulatory perspective.

Cytostatic versus Cytocidal Activities of Chloroquine Analogues and Inhibition of Hemozoin Crystal Growth

PubMed Central

Gorka, Alexander P.; Alumasa, John N.; Sherlach, Katy S.; Jacobs, Lauren M.; Nickley, Katherine B.; Brower, Jonathan P.; de Dios, Angel C.

2013-01-01

We report an improved, nonhazardous, high-throughput assay for in vitro quantification of antimalarial drug inhibition of β-hematin (hemozoin) crystallization performed under conditions that are more physiological relative to previous assays. The assay uses the differential detergent solubility of crystalline and noncrystalline forms of heme and is optimized via the use of lipid catalyst. Using this assay, we quantify the effect of pH on the crystal growth-inhibitory activities of current quinoline antimalarials, evaluate the catalytic efficiencies of different lipids, and test for a possible correlation between hemozoin inhibition by drugs versus their antiplasmodial activity. Consistent with several previous reports, we found a good correlation between hemozoin inhibition potency versus cytostatic antiplasmodial potency (50% inhibitory concentration) for a series of chloroquine (CQ) analogues. However, we found no correlation between hemozoin inhibition potency and cytocidal antiplasmodial potency (50% lethal dose) for the same drugs, suggesting that cellular targets for these two layers of 4-aminoquinoline drug activity differ. This important concept is also explored further for QN and its stereoisomers in the accompanying paper (A. P. Gorka, K. S. Sherlach, A. C. de Dios, and P. D. Roepe, Antimicrob. Agents Chemother. 57:365–374, 2013). PMID:23114783

Cytostatic versus cytocidal activities of chloroquine analogues and inhibition of hemozoin crystal growth.

PubMed

Gorka, Alexander P; Alumasa, John N; Sherlach, Katy S; Jacobs, Lauren M; Nickley, Katherine B; Brower, Jonathan P; de Dios, Angel C; Roepe, Paul D

2013-01-01

We report an improved, nonhazardous, high-throughput assay for in vitro quantification of antimalarial drug inhibition of β-hematin (hemozoin) crystallization performed under conditions that are more physiological relative to previous assays. The assay uses the differential detergent solubility of crystalline and noncrystalline forms of heme and is optimized via the use of lipid catalyst. Using this assay, we quantify the effect of pH on the crystal growth-inhibitory activities of current quinoline antimalarials, evaluate the catalytic efficiencies of different lipids, and test for a possible correlation between hemozoin inhibition by drugs versus their antiplasmodial activity. Consistent with several previous reports, we found a good correlation between hemozoin inhibition potency versus cytostatic antiplasmodial potency (50% inhibitory concentration) for a series of chloroquine (CQ) analogues. However, we found no correlation between hemozoin inhibition potency and cytocidal antiplasmodial potency (50% lethal dose) for the same drugs, suggesting that cellular targets for these two layers of 4-aminoquinoline drug activity differ. This important concept is also explored further for QN and its stereoisomers in the accompanying paper (A. P. Gorka, K. S. Sherlach, A. C. de Dios, and P. D. Roepe, Antimicrob. Agents Chemother. 57:365-374, 2013).

A dimensional approach to understanding severity estimates and risk correlates of marijuana abuse and dependence in adults

PubMed Central

WU, LI-TZY; WOODY, GEORGE E.; YANG, CHONGMING; PAN, JENG-JONG; REEVE, BRYCE B.; BLAZER, DAN G.

2012-01-01

While item response theory (IRT) research shows a latent severity trait underlying response patterns of substance abuse and dependence symptoms, little is known about IRT-based severity estimates in relation to clinically relevant measures. In response to increased prevalences of marijuana-related treatment admissions, an elevated level of marijuana potency, and the debate on medical marijuana use, we applied dimensional approaches to understand IRT-based severity estimates for marijuana use disorders (MUDs) and their correlates while simultaneously considering gender- and race/ethnicity-related differential item functioning (DIF). Using adult data from the 2008 National Survey on Drug Use and Health (N=37,897), DSM-IV criteria for MUDs among past-year marijuana users were examined by IRT, logistic regression, and multiple indicators–multiple causes (MIMIC) approaches. Among 6,917 marijuana users, 15% met criteria for a MUD; another 24% exhibited subthreshold dependence. Abuse criteria were highly correlated with dependence criteria (correlation=0.90), indicating unidimensionality; item information curves revealed redundancy in multiple criteria. MIMIC analyses showed that MUD criteria were positively associated with weekly marijuana use, early marijuana use, other substance use disorders, substance abuse treatment, and serious psychological distress. African Americans and Hispanics showed higher levels of MUDs than whites, even after adjusting for race/ethnicity-related DIF. The redundancy in multiple criteria suggests an opportunity to improve efficiency in measuring symptom-level manifestations by removing low-informative criteria. Elevated rates of MUDs among African Americans and Hispanics require research to elucidate risk factors and improve assessments of MUDs for different racial/ethnic groups. PMID:22351489

Short-term effects of repeated olfactory administration of homeopathic sulphur or pulsatilla on electroencephalographic alpha power in healthy young adults.

PubMed

Bell, Iris R; Brooks, Audrey J; Howerter, Amy; Jackson, Nicholas; Schwartz, Gary E

2011-10-01

Homeopathic pathogenetic trials usually rely on symptom self report measures. Adding objective biomarkers could enhance detection of subtle initial remedy effects. The present feasibility study examined electroencephalographic (EEG) effects of repeated olfactory administration of two polycrest remedies. College student volunteers (ages 18-30, both sexes) from an introductory psychology course were screened for good health and relatively elevated Sulphur or Pulsatilla symptom scores on the Homeopathic Constitutional Type Questionnaire (CTQ). Subjects underwent a series of 3 once-weekly double-blind sessions during which they repeatedly sniffed the remedy matched to their CTQ type and solvent controls. Each remedy was given in a 6c, 12c, and 30c potency, one potency per week, in randomly assigned order. Solvent controls included both plain distilled water and a water-ethanol (95%) solution. All sniff test solutions were further diluted just prior to laboratory sessions (0.5 ml test solution in 150 ml distilled water). Within a session, remedies and control solvents were administered via 2-s sniffs (8 sniffs of each of 4 different succussion levels for the potency in randomized order). Primary outcome variable was relative EEG power (alpha 1 8-10 Hz; alpha 2 10-12 Hz) averaged over 19 electrode sites, including all succussions for a given potency. Mixed-effect models revealed significant main effects for remedy type (Sulphur >Pulsatilla) in both alpha bands, controlling for gender, baseline resting EEG alpha, and solvent control responses. Additional analyses showed significant nonlinear interactions between dilution and time (weekly session) in alpha 2 for both remedies and alpha 1 for Sulphur. EEG alpha offers an objective biomarker of remedy effects for future studies and potential method for distinguishing time-dependent effects of specific remedies and remedy potencies from one another. Copyright © 2011 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

Short-Term Effects of Repeated Olfactory Administration of Homeopathic Sulphur or Pulsatilla on Electroencephalographic Alpha Power in Healthy Young Adults

PubMed Central

Bell, Iris R.; Brooks, Audrey J.; Howerter, Amy; Jackson, Nicholas; Schwartz, Gary E.

2011-01-01

Introduction Homeopathic pathogenetic trials usually rely on symptom self report measures. Adding objective biomarkers could enhance detection of subtle initial remedy effects. The present feasibility study examined electroencephalographic (EEG) effects of repeated olfactory administration of two polycrest remedies. Methods College student volunteers (ages 18–30, both sexes) from an introductory psychology course were screened for good health and relatively elevated Sulphur OR Pulsatilla symptom scores on the Homeopathic Constitutional Type Questionnaire. Subjects underwent a series of 3 once-weekly double-blind sessions during which they repeatedly sniffed the remedy matched to their CTQ type and solvent controls. Each remedy was given in a 6c, 12c, and 30c potency, one potency per week, in randomly assigned order. Solvent controls included both plain distilled water and a water-ethanol (95%) solution. All sniff test solutions were further diluted just prior to laboratory sessions (0.5 ml test solution in 150 ml distilled water). Within a session, remedies and control solvents were administered via 2-second sniffs (8 sniffs of each of 4 different succussion levels for the potency in randomized order). Primary outcome variable was relative EEG power (alpha 1 8–10 hertz; alpha 2 10–12 hertz) averaged over 19 electrode sites, including all succussions for a given potency. Results Mixed-effect models revealed significant main effects for remedy type (Sulphur>Pulsatilla) in both alpha bands, controlling for gender, baseline resting EEG alpha, and solvent control responses. Additional analyses showed significant non-linear interactions between dilution and time (weekly session) in alpha 2 for both remedies and alpha 1 for Sulphur. Conclusion EEG alpha offers an objective biomarker of remedy effects for future studies and potential method for distinguishing time-dependent effects of specific remedies and remedy potencies from one another. PMID:21962194

Diverse amide analogs of sulindac for cancer treatment and prevention.

PubMed

Mathew, Bini; Hobrath, Judith V; Connelly, Michele C; Kiplin Guy, R; Reynolds, Robert C

2017-10-15

Sulindac is a non-steroidal anti-inflammatory drug (NSAID) that has shown significant anticancer activity. Sulindac sulfide amide (1) possessing greatly reduced COX-related inhibition relative to sulindac displayed in vivo antitumor activity that was comparable to sulindac in a human colon tumor xenograft model. Inspired by these observations, a panel of diverse sulindac amide derivatives have been synthesized and their activity probed against three cancer cell lines (prostate, colon and breast). A neutral analog, compound 79 was identified with comparable potency relative to lead 1 and activity against a panel of lymphoblastic leukemia cell lines. Several new series also show good activity relative to the parent (1), including five analogs that also possess nanomolar inhibitory potencies against acute lymphoblastic leukemia cells. Several new analogs identified may serve as anticancer lead candidates for further development. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Potency assay development for cellular therapy products: an ISCT review of the requirements and experiences in the industry.

PubMed

Bravery, Christopher A; Carmen, Jessica; Fong, Timothy; Oprea, Wanda; Hoogendoorn, Karin H; Woda, Juliana; Burger, Scott R; Rowley, Jon A; Bonyhadi, Mark L; Van't Hof, Wouter

2013-01-01

The evaluation of potency plays a key role in defining the quality of cellular therapy products (CTPs). Potency can be defined as a quantitative measure of relevant biologic function based on the attributes that are linked to relevant biologic properties. To achieve an adequate assessment of CTP potency, appropriate in vitro or in vivo laboratory assays and properly controlled clinical data need to be created. The primary objective of a potency assay is to provide a mechanism by which the manufacturing process and the final product for batch release are scrutinized for quality, consistency and stability. A potency assay also provides the basis for comparability assessment after process changes, such as scale-up, site transfer and new starting materials (e.g., a new donor). Potency assays should be in place for early clinical development, and validated assays are required for pivotal clinical trials. Potency is based on the individual characteristics of each individual CTP, and the adequacy of potency assays will be evaluated on a case-by-case basis by regulatory agencies. We provide an overview of the expectations and challenges in development of potency assays specific for CTPs; several real-life experiences from the cellular therapy industry are presented as illustrations. The key observation and message is that aggressive early investment in a solid potency evaluation strategy can greatly enhance eventual CTP deployment because it can mitigate the risk of costly product failure in late-stage development. Copyright © 2013. Published by Elsevier Inc.

Supplement to the Carcinogenic Potency Database (CPDB): Results ofanimal bioassays published in the general literature through 1997 and bythe National Toxicology Program in 1997-1998

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gold, Lois Swirsky; Manley, Neela B.; Slone, Thomas H.

2005-04-08

The Carcinogenic Potency Database (CPDB) is a systematic and unifying resource that standardizes the results of chronic, long-term animal cancer tests which have been conducted since the 1950s. The analyses include sufficient information on each experiment to permit research into many areas of carcinogenesis. Both qualitative and quantitative information is reported on positive and negative experiments that meet a set of inclusion criteria. A measure of carcinogenic potency, TD50 (daily dose rate in mg/kg body weight/day to induce tumors in half of test animals that would have remained tumor-free at zero dose), is estimated for each tissue-tumor combination reported. Thismore » article is the ninth publication of a chronological plot of the CPDB; it presents results on 560 experiments of 188 chemicals in mice, rats, and hamsters from 185 publications in the general literature updated through 1997, and from 15 Reports of the National Toxicology Program in 1997-1998. The test agents cover a wide variety of uses and chemical classes. The CPDB Web Site(http://potency.berkeley.edu/) presents the combined database of all published plots in a variety of formats as well as summary tables by chemical and by target organ, supplemental materials on dosing and survival, a detailed guide to using the plot formats, and documentation of methods and publications. The overall CPDB, including the results in this article, presents easily accessible results of 6153 experiments on 1485 chemicals from 1426 papers and 429 NCI/NTP (National Cancer Institute/National Toxicology program) Technical Reports. A tab-separated format of the full CPDB for reading the data into spreadsheets or database applications is available on the Web Site.« less

Development of Special Biological Products

DTIC Science & Technology

1981-01-01

Rocky Mountain Spotted Fever (RMSF) 20. Continued B. Tissue Culture / ?Two production lots of FRhL-2 dnd three of MRC-5 were stabilized...104) was potency tested. J. Q Fever Vaccine Storage Stability Potency Testing Q fever vaccine (NDBR 105) was put on potency test. K. Rocky Mountain Spotted Fever (RMSF...Fever Vaccine Storage Stability Potency Testing Two lots of Q fever vaccine (NDBR 105) were put on potency test. K. Rocky Mountain Spotted Fever

Collaborative study to assess the suitability of a candidate International Standard for yellow fever vaccine.

PubMed

Ferguson, Morag; Heath, Alan

2004-12-01

Yellow fever vaccines are routinely assayed by plaque assay. However, the results of these assays are then converted into mouse LD(50) using correlations/conversion factors which, in many cases, were established many years ago. The minimum required potency in WHO Recommendations is 10(3) LD(50)/dose. Thirteen participants from 8 countries participated in a collaborative study whose aim was to assess the suitability of two candidate preparations to serve as an International Standard for yellow fever vaccine. In addition, the study investigated the relationship between the mouse LD(50) test and plaque forming units with a view to updating the WHO recommendations. Plaque assays were more reproducible than mouse assays, as expected. Differences in sensitivities of plaque assays were observed between laboratories but these differences appear to be consistent within a laboratory for all samples and the expression of potency relative to the candidate standard vaccine improved the reproducibility of assays between laboratories. However, the use of potencies had little effect on the between laboratory variability in mouse LD(50) assays. There appears to be a consistent relationship between overall mean LD(50) and plaques titre for all study preparations other than sample E. The slope of the correlation curve is >1 and it would appear that 10(3) LD(50) is approximately equivalent to 10(4) plaque forming units (PFU), based on the overall means of all laboratory results. The First International Standard for yellow fever vaccine, NIBSC Code 99/616, has been established as the First International Standard for yellow fever vaccine by the Expert Committee of Biological Standards of the World Health Organisation. The International Standard has been arbitrarily assigned a potency of 10(4.5) International Units (IU) per ampoule. Manufacturers and National Control Laboratories are including the First International Standard for yellow fever vaccine in routine assays so that the minimum potency in IU of vaccines released for use and which meet the current minimum potency of 10(3) LD(50) in mouse assays, can be determined. These data will be analysed before a review of the WHO requirements, including the minimum potency per dose, is undertaken.

Relative effect potency estimates of dioxin-like activity for dioxins, furans, and dioxin-like PCBs in adults based on cytochrome P450 1A1 and 1B1 gene expression in blood.

PubMed

Wimmerová, Soňa; van den Berg, Martin; Chovancová, Jana; Patayová, Henrieta; Jusko, Todd A; van Duursen, Majorie B M; Palkovičová Murínová, Ľubica; Canton, Rocio F; van Ede, Karin I; Trnovec, Tomáš

2016-11-01

In the risk assessment of PCDDs, PCDFs, and dioxin-like (DL) PCBs, regulatory authorities support the use of the toxic equivalency factor (TEF)-scheme derived from a heterogeneous data set of the relative effect potency (REPs) estimates. We sought to determine REPs for dioxin-like compounds (DLCs) using expression of cytochrome P450 (CYP) 1A1 and 1B1 mRNA in human peripheral blood mononuclear cells representing two different pathways. We used a sex and age adjusted regression-based approach comparing the strength of association between each DLC and the cytochrome P450 (CYP) 1A1 and 1B1 mRNA expression in 320 adults residing in an organochlorine-polluted area of eastern Slovakia. We calculated REPs based on CYP1A1 expression for 4 PCDDs, 8 PCDFs, and 1 PCB congener, and based on CYP1B1 expression for 5 PCDFs and 11 PCB congeners. REPs from CYP1A1 correlated with REPs previously derived from thyroid volume (ρ=0.85; p<0.001) and serum FT4 (ρ=0.77; p=0.009). The 13 log REPs from CYP1A1 correlated with log WHO-TEFs (r=0.63; p=0.015) and 11 log PCB REPs with PCB consensus toxicity factors (CTFs) for compounds with WHO-TEFs (r=0.80; p=0.003). The complete set of derived 56 log REPs correlated with the log CTFs (r=0.77; p=0.001) and log WHO-TEFs (r=0.81; p<0.001). REPs calculated from thyroid and cytochrome P450 endpoints realistically reflect human exposure scenarios because they are based on human chronic and low-dose exposures. While the CYP 1A1 seems more suitable for toxicity evaluation of PCDD/Fs, the CYP 1B1 is more apt for PCDFs and PCBs and reflects different pathways. Copyright © 2016 Elsevier Ltd. All rights reserved.

Structure-Activity Relationship Studies on a Macrocyclic Agouti-Related Protein (AGRP) Scaffold Reveal Agouti Signaling Protein (ASP) Residue Substitutions Maintain Melanocortin-4 Receptor Antagonist Potency and Result in Inverse Agonist Pharmacology at the Melanocortin-5 Receptor.

PubMed

Ericson, Mark D; Freeman, Katie T; Schnell, Sathya M; Fleming, Katlyn A; Haskell-Luevano, Carrie

2017-10-12

The melanocortin system consists of five reported receptors, agonists from the proopiomelanocortin gene transcript, and two antagonists, agouti-signaling protein (ASP) and agouti-related protein (AGRP). For both ASP and AGRP, the hypothesized Arg-Phe-Phe pharmacophores are on exposed β-hairpin loops. In this study, the Asn and Ala positions of a reported AGRP macrocyclic scaffold (c[Pro-Arg-Phe-Phe-Asn-Ala-Phe-DPro]) were explored with 14-compound and 8-compound libraries, respectively, to generate more potent, selective melanocortin receptor antagonists. Substituting diaminopropionic acid (Dap), DDap, and His at the Asn position yielded potent MC4R ligands, while replacing Ala with Ser maintained MC4R potency. Since these substitutions correlate to ASP loop residues, an additional Phe to Ala substitution was synthesized and observed to maintain MC4R potency. Seventeen compounds also possessed inverse agonist activity at the MC5R, the first report of this pharmacology. These findings are useful in developing molecular probes to study negative energy balance conditions and unidentified functions of the MC5R.

Chemical Tuning Enhances Both Potency Toward Nrf2 and In Vitro Therapeutic Index of Triterpenoids

PubMed Central

Copple, Ian M.; Shelton, Luke M.; Walsh, Joanne; Kratschmar, Denise V.; Lister, Adam; Odermatt, Alex; Goldring, Christopher E.; Dinkova-Kostova, Albena T.; Honda, Tadashi; Park, B. Kevin

2014-01-01

The transcription factor Nrf2 protects against a number of experimental pathologies, and is a promising therapeutic target. The clinical investigation of a potent Nrf2-inducing agent, the triterpenoid (TP) bardoxolone methyl (BARD), was recently halted due to adverse cardiovascular events in chronic kidney disease patients, although the underlying mechanisms are yet to be resolved. The majority of small molecule Nrf2 inducers are electrophilic and trigger Nrf2 accumulation via the chemical modification of its redox-sensitive repressor Keap1. Therefore, it is pertinent to question whether the therapeutic targeting of Nrf2 could be hindered in many cases by the inherent reactivity of a small molecule inducer toward unintended cellular targets, a key mechanism of drug toxicity. Using H4IIE-ARE8L hepatoma cells, we have examined the relationship between (a) Nrf2 induction potency, (b) toxicity and (c) in vitro therapeutic index (ratio of b:a) for BARD and a number of other small molecule activators of Nrf2. We show that BARD exhibits the highest potency toward Nrf2 and the largest in vitro therapeutic index among compounds that have been investigated clinically (namely BARD, sulforaphane and dimethylfumarate). Through further examination of structurally related TPs, we demonstrate that an increase in potency toward Nrf2 is associated with a relatively smaller increase in toxicity, indicating that medicinal chemistry can be used to enhance the specificity of a compound as an inducer of Nrf2 signaling whilst simultaneously increasing its therapeutic index. These findings will inform the continuing design and development of drugs targeting Nrf2. PMID:24798383

Potency values from the local lymph node assay: application to classification, labelling and risk assessment.

PubMed

Loveless, S E; Api, A-M; Crevel, R W R; Debruyne, E; Gamer, A; Jowsey, I R; Kern, P; Kimber, I; Lea, L; Lloyd, P; Mehmood, Z; Steiling, W; Veenstra, G; Woolhiser, M; Hennes, C

2010-02-01

Hundreds of chemicals are contact allergens but there remains a need to identify and characterise accurately skin sensitising hazards. The purpose of this review was fourfold. First, when using the local lymph node assay (LLNA), consider whether an exposure concentration (EC3 value) lower than 100% can be defined and used as a threshold criterion for classification and labelling. Second, is there any reason to revise the recommendation of a previous ECETOC Task Force regarding specific EC3 values used for sub-categorisation of substances based upon potency? Third, what recommendations can be made regarding classification and labelling of preparations under GHS? Finally, consider how to integrate LLNA data into risk assessment and provide a rationale for using concentration responses and corresponding no-effect concentrations. Although skin sensitising chemicals having high EC3 values may represent only relatively low risks to humans, it is not possible currently to define an EC3 value below 100% that would serve as an appropriate threshold for classification and labelling. The conclusion drawn from reviewing the use of distinct categories for characterising contact allergens was that the most appropriate, science-based classification of contact allergens according to potency is one in which four sub-categories are identified: 'extreme', 'strong', 'moderate' and 'weak'. Since draining lymph node cell proliferation is related causally and quantitatively to potency, LLNA EC3 values are recommended for determination of a no expected sensitisation induction level that represents the first step in quantitative risk assessment. 2009 Elsevier Inc. All rights reserved.

Transactivation potencies of the Baikal seal (Pusa sibirica) peroxisome proliferator-activated receptor α by perfluoroalkyl carboxylates and sulfonates: estimation of PFOA induction equivalency factors.

PubMed

Ishibashi, Hiroshi; Kim, Eun-Young; Iwata, Hisato

2011-04-01

The present study assessed the transactivation potencies of the Baikal seal (Pusa sibirica) peroxisome proliferator-activated receptor α (BS PPARα) by perfluorochemicals (PFCs) having various carbon chain lengths (C4-C12) using an in vitro reporter gene assay. Among the twelve PFCs treated with a range of 7.8-250 μM concentration, eight perfluoroalkyl carboxylates (PFCAs) and two perfluoroalkyl sulfonates (PFSAs) induced BS PPARα-mediated transcriptional activities in a dose-dependent manner. To compare the BS PPARα transactivation potencies of PFCs, the present study estimated the PFOA induction equivalency factors (IEFs), a ratio of the 50% effective concentration of PFOA to the concentration of each compound that can induce the response corresponding to 50% of the maximal response of PFOA. The order of IEFs for the PFCs was as follows: PFOA (IEF: 1)>PFHpA (0.89)>PFNA (0.61)>PFPeA (0.50)>PFHxS (0.41)>PFHxA (0.38)≈PFDA (0.37)>PFBA (0.26)=PFOS (0.26)>PFUnDA (0.15)≫PFDoDA and PFBuS (not activated). The structure-activity relationship analysis showed that PFCAs having more than seven perfluorinated carbons had a negative correlation (r=-1.0, p=0.017) between the number of perfluorinated carbons and the IEF of PFCAs, indicating that the number of perfluorinated carbon of PFCAs is one of the factors determining the transactivation potencies of the BS PPARα. The analysis also indicated that PFCAs were more potent than PFSAs with the same number of perfluorinated carbons. Treatment with a mixture of ten PFCs showed an additive action on the BS PPARα activation. Using IEFs of individual PFCs and hepatic concentrations of PFCs in the liver of wild Baikal seals, the PFOA induction equivalents (IEQs, 5.3-58 ng IEQ/g wet weight) were calculated. The correlation analysis revealed that the hepatic total IEQs showed a significant positive correlation with the hepatic expression levels of cytochrome P450 4A-like protein (r=0.53, p=0.036). This suggests that our approach may be useful for assessing the potential PPARα-mediated biological effects of complex mixtures of PFCs in wild Baikal seal population.

Relative effect potency estimates of dioxin-like activity for dioxins, furans, and dioxin-like PCBs in adults based on two thyroid outcomes.

PubMed

Trnovec, Tomáš; Jusko, Todd A; Šovčíková, Eva; Lancz, Kinga; Chovancová, Jana; Patayová, Henrieta; Palkovičová, L'ubica; Drobná, Beata; Langer, Pavel; Van den Berg, Martin; Dedik, Ladislav; Wimmerová, Soňa

2013-08-01

Toxic equivalency factors (TEFs) are an important component in the risk assessment of dioxin-like human exposures. At present, this concept is based mainly on in vivo animal experiments using oral dosage. Consequently, the current human TEFs derived from mammalian experiments are applicable only for exposure situations in which oral ingestion occurs. Nevertheless, these "intake" TEFs are commonly-but incorrectly-used by regulatory authorities to calculate "systemic" toxic equivalents (TEQs) based on human blood and tissue concentrations, which are used as biomarkers for either exposure or effect. We sought to determine relative effect potencies (REPs) for systemic human concentrations of dioxin-like mixture components using thyroid volume or serum free thyroxine (FT4) concentration as the outcomes of interest. We used a benchmark concentration and a regression-based approach to compare the strength of association between each dioxin-like compound and the thyroid end points in 320 adults residing in an organochlorine-polluted area of eastern Slovakia. REPs calculated from thyroid volume and FT4 were similar. The regression coefficient (β)-derived REP data from thyroid volume and FT4 level were correlated with the World Health Organization (WHO) TEF values (Spearman r = 0.69, p = 0.01 and r = 0.62, p = 0.03, respectively). The calculated REPs were mostly within the minimum and maximum values for in vivo REPs derived by other investigators. Our REPs calculated from thyroid end points realistically reflect human exposure scenarios because they are based on chronic, low-dose human exposures and on biomarkers reflecting body burden. Compared with previous results, our REPs suggest higher sensitivity to the effects of dioxin-like compounds.

LLNA variability: An essential ingredient for a comprehensive assessment of non-animal skin sensitization test methods and strategies.

PubMed

Hoffmann, Sebastian

2015-01-01

The development of non-animal skin sensitization test methods and strategies is quickly progressing. Either individually or in combination, the predictive capacity is usually described in comparison to local lymph node assay (LLNA) results. In this process the important lesson from other endpoints, such as skin or eye irritation, to account for variability reference test results - here the LLNA - has not yet been fully acknowledged. In order to provide assessors as well as method and strategy developers with appropriate estimates, we investigated the variability of EC3 values from repeated substance testing using the publicly available NICEATM (NTP Interagency Center for the Evaluation of Alternative Toxicological Methods) LLNA database. Repeat experiments for more than 60 substances were analyzed - once taking the vehicle into account and once combining data over all vehicles. In general, variability was higher when different vehicles were used. In terms of skin sensitization potential, i.e., discriminating sensitizer from non-sensitizers, the false positive rate ranged from 14-20%, while the false negative rate was 4-5%. In terms of skin sensitization potency, the rate to assign a substance to the next higher or next lower potency class was approx.10-15%. In addition, general estimates for EC3 variability are provided that can be used for modelling purposes. With our analysis we stress the importance of considering the LLNA variability in the assessment of skin sensitization test methods and strategies and provide estimates thereof.

New Equilibrium Models of Drug-Receptor Interactions Derived from Target-Mediated Drug Disposition.

PubMed

Peletier, Lambertus A; Gabrielsson, Johan

2018-05-14

In vivo analyses of pharmacological data are traditionally based on a closed system approach not incorporating turnover of target and ligand-target kinetics, but mainly focussing on ligand-target binding properties. This study incorporates information about target and ligand-target kinetics parallel to binding. In a previous paper, steady-state relationships between target- and ligand-target complex versus ligand exposure were derived and a new expression of in vivo potency was derived for a circulating target. This communication is extending the equilibrium relationships and in vivo potency expression for (i) two separate targets competing for one ligand, (ii) two different ligands competing for a single target and (iii) a single ligand-target interaction located in tissue. The derived expressions of the in vivo potencies will be useful both in drug-related discovery projects and mechanistic studies. The equilibrium states of two targets and one ligand may have implications in safety assessment, whilst the equilibrium states of two competing ligands for one target may cast light on when pharmacodynamic drug-drug interactions are important. The proposed equilibrium expressions for a peripherally located target may also be useful for small molecule interactions with extravascularly located targets. Including target turnover, ligand-target complex kinetics and binding properties in expressions of potency and efficacy will improve our understanding of within and between-individual (and across species) variability. The new expressions of potencies highlight the fact that the level of drug-induced target suppression is very much governed by target turnover properties rather than by the target expression level as such.

9 CFR 113.9 - New potency test.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false New potency test. 113.9 Section 113.9 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES... New potency test. A potency test written into the filed Outline of Production for a product shall be...

Contributions of different modes of TRPV1 activation to TRPV1 antagonist-induced hyperthermia.

PubMed

Garami, Andras; Shimansky, Yury P; Pakai, Eszter; Oliveira, Daniela L; Gavva, Narender R; Romanovsky, Andrej A

2010-01-27

Transient receptor potential vanilloid-1 (TRPV1) antagonists are widely viewed as next-generation pain therapeutics. However, these compounds cause hyperthermia, a serious side effect. TRPV1 antagonists differentially block three modes of TRPV1 activation: by heat, protons, and chemical ligands (e.g., capsaicin). We asked what combination of potencies in these three modes of TRPV1 activation corresponds to the lowest potency of a TRPV1 antagonist to cause hyperthermia. We studied hyperthermic responses of rats, mice, and guinea pigs to eight TRPV1 antagonists with different pharmacological profiles and used mathematical modeling to find a relative contribution of the blockade of each activation mode to the development of hyperthermia. We found that the hyperthermic effect has the highest sensitivity to the extent of TRPV1 blockade in the proton mode (0.43 to 0.65) with no to moderate sensitivity in the capsaicin mode (-0.01 to 0.34) and no sensitivity in the heat mode (0.00 to 0.01). We conclude that hyperthermia-free TRPV1 antagonists do not block TRPV1 activation by protons, even if they are potent blockers of the heat mode, and that decreasing the potency to block the capsaicin mode may further decrease the potency to cause hyperthermia.

Contributions of different modes of TRPV1 activation to TRPV1 antagonist-induced hyperthermia

PubMed Central

Garami, Andras; Shimansky, Yury P.; Pakai, Eszter; Oliveira, Daniela L.; Gavva, Narender R.; Romanovsky, Andrej A.

2010-01-01

Transient receptor potential vanilloid-1 (TRPV1) antagonists are widely viewed as next-generation pain therapeutics. However, these compounds cause hyperthermia, a serious side effect. TRPV1 antagonists differentially block three modes of TRPV1 activation: by heat, protons, and chemical ligands (e.g., capsaicin). We asked what combination of potencies in these three modes of TRPV1 activation corresponds to the lowest potency of a TRPV1 antagonist to cause hyperthermia. We studied hyperthermic responses of rats, mice, and guinea pigs to eight TRPV1 antagonists with different pharmacological profiles and used mathematical modeling to find a relative contribution of the blockade of each activation mode to the development of hyperthermia. We have found that the hyperthermic effect has the highest sensitivity to the extent of TRPV1 blockade in the proton mode (0.43 to 0.65) with no to moderate sensitivity in the capsaicin mode (-0.01 to 0.34) and no sensitivity in the heat mode (0.00 to 0.01). We conclude that hyperthermia-free TRPV1 antagonists do not block TRPV1 activation by protons, even if they are potent blockers of the heat mode, and that decreasing the potency to block the capsaicin mode may further decrease the potency to cause hyperthermia. PMID:20107070

Cumulative high doses of inhaled formoterol have less systemic effects in asthmatic children 6–11 years-old than cumulative high doses of inhaled terbutaline

PubMed Central

Kaae, Rikke; Agertoft, Lone; Pedersen, Sören; Nordvall, S Lennart; Pedroletti, Christophe; Bengtsson, Thomas; Johannes-Hellberg, Ingegerd; Rosenborg, Johan

2004-01-01

Objectives To evaluate high dose tolerability and relative systemic dose potency between inhaled clinically equipotent dose increments of formoterol and terbutaline in children. Methods Twenty boys and girls (6–11 years-old) with asthma and normal ECGs were studied. Ten doses of formoterol (Oxis®) 4.5 µg (F4.5) or terbutaline (Bricanyl®) 500 µg (T500) were inhaled cumulatively via a dry powder inhaler (Turbuhaler®) over 1 h (three patients) or 2.5 h (17 patients) and compared to a day of no treatment, in a randomised, double-blind (active treatments only), crossover trial. Blood pressure (BP), ECG, plasma potassium, glucose, lactate, and adverse events were monitored up to 10 h to assess tolerability and relative systemic dose potency. Results Formoterol and terbutaline had significant β2-adrenergic effects on most outcomes. Apart from the effect on systolic BP, QRS duration and PR interval, the systemic effects were significantly more pronounced with terbutaline than with formoterol. Thus, mean minimum plasma potassium, was suppressed from 3.56 (95% confidence interval, CI: 3.48–3.65) mmol l−1 on the day of no treatment to 2.98 (CI: 2.90–3.08) after 10 × F4.5 and 2.70 (CI: 2.61–2.78) mmol l−1 after 10 × T500, and maximum Q-Tc (heart rate corrected Q-T interval [Bazett's formula]) was prolonged from 429 (CI: 422–435) ms on the day of no treatment, to 455 (CI: 448–462) ms after 10 × F4.5 and 470 (CI: 463–476) ms after 10 × T500. Estimates of relative dose potency indicated that F4.5 µg had the same systemic activity as the clinically less effective dose of 250 µg terbutaline. The duration of systemic effects differed marginally between treatments. Spontaneously reported adverse events (most frequently tremor) were fewer with formoterol (78% of the children) than with terbutaline (95%). A serious adverse event occurred after inhalation of 45 µg formoterol over the 1 h dosing time, that prompted the extension of dosing time to 2.5 h. Conclusions Multiple inhalations over 2.5 h of formoterol (4.5 µg) via Turbuhaler® are at least as safe as and associated with less systemic effects than multiple inhalations of the clinically equipotent dose of terbutaline (500 µg) in children with asthma. PMID:15373934

Cumulative high doses of inhaled formoterol have less systemic effects in asthmatic children 6-11 years-old than cumulative high doses of inhaled terbutaline.

PubMed

Kaae, Rikke; Agertoft, Lone; Pedersen, Sören; Nordvall, S Lennart; Pedroletti, Christophe; Bengtsson, Thomas; Johannes-Hellberg, Ingegerd; Rosenborg, Johan

2004-10-01

To evaluate high dose tolerability and relative systemic dose potency between inhaled clinically equipotent dose increments of formoterol and terbutaline in children. Twenty boys and girls (6-11 years-old) with asthma and normal ECGs were studied. Ten doses of formoterol (Oxis) 4.5 microg (F4.5) or terbutaline (Bricanyl) 500 microg (T500) were inhaled cumulatively via a dry powder inhaler (Turbuhaler) over 1 h (three patients) or 2.5 h (17 patients) and compared to a day of no treatment, in a randomised, double-blind (active treatments only), crossover trial. Blood pressure (BP), ECG, plasma potassium, glucose, lactate, and adverse events were monitored up to 10 h to assess tolerability and relative systemic dose potency. Formoterol and terbutaline had significant beta2-adrenergic effects on most outcomes. Apart from the effect on systolic BP, QRS duration and PR interval, the systemic effects were significantly more pronounced with terbutaline than with formoterol. Thus, mean minimum plasma potassium, was suppressed from 3.56 (95% confidence interval, CI: 3.48-3.65) mmol l(-1) on the day of no treatment to 2.98 (CI: 2.90-3.08) after 10 x F4.5 and 2.70 (CI: 2.61-2.78) mmol l(-1) after 10 x T500, and maximum Q-Tc (heart rate corrected Q-T interval [Bazett's formula]) was prolonged from 429 (CI: 422-435) ms on the day of no treatment, to 455 (CI: 448-462) ms after 10 x F4.5 and 470 (CI: 463-476) ms after 10 x T500. Estimates of relative dose potency indicated that F4.5 microg had the same systemic activity as the clinically less effective dose of 250 microg terbutaline. The duration of systemic effects differed marginally between treatments. Spontaneously reported adverse events (most frequently tremor) were fewer with formoterol (78% of the children) than with terbutaline (95%). A serious adverse event occurred after inhalation of 45 microg formoterol over the 1 h dosing time, that prompted the extension of dosing time to 2.5 h. Multiple inhalations over 2.5 h of formoterol (4.5 microg) via Turbuhaler) are at least as safe as and associated with less systemic effects than multiple inhalations of the clinically equipotent dose of terbutaline (500 microg) in children with asthma. Copyright 2004 Blackwell Publishing Ltd

Effect of high-potency cannabis on corpus callosum microstructure.

PubMed

Rigucci, S; Marques, T R; Di Forti, M; Taylor, H; Dell'Acqua, F; Mondelli, V; Bonaccorso, S; Simmons, A; David, A S; Girardi, P; Pariante, C M; Murray, R M; Dazzan, P

2016-03-01

The use of cannabis with higher Δ9-tetrahydrocannabinol content has been associated with greater risk, and earlier onset, of psychosis. However, the effect of cannabis potency on brain morphology has never been explored. Here, we investigated whether cannabis potency and pattern of use are associated with changes in corpus callosum (CC) microstructural organization, in patients with first-episode psychosis (FEP) and individuals without psychosis, cannabis users and non-users. The CC of 56 FEP (37 cannabis users) and 43 individuals without psychosis (22 cannabis users) was virtually dissected and segmented using diffusion tensor imaging tractography. The diffusion index of fractional anisotropy, mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity was calculated for each segment. Across the whole sample, users of high-potency cannabis had higher total CC MD and higher total CC AD than both low-potency users and those who never used (p = 0.005 and p = 0.004, respectively). Daily users also had higher total CC MD and higher total CC AD than both occasional users and those who never used (p = 0.001 and p < 0.001, respectively). However, there was no effect of group (patient/individuals without psychosis) or group x potency interaction for either potency or frequency of use. The within-group analysis showed in fact that the effects of potency and frequency were similar in FEP users and in users without psychosis. Frequent use of high-potency cannabis is associated with disturbed callosal microstructural organization in individuals with and without psychosis. Since high-potency preparations are now replacing traditional herbal drugs in many European countries, raising awareness about the risks of high-potency cannabis is crucial.

Study of polycyclic aromatic hydrocarbons in atmospheric particulate matter of an urban area with iron and steel mills.

PubMed

Menezes, Helvécio C; Cardeal, Zenilda L

2012-07-01

Polycyclic aromatic hydrocarbons (PAHs) were analyzed from ambient air particulate matter <10 µm (PM(10) ) and the total suspended particulate (TSP) phase continuously for a period of six months (May-October 2010) at five sampling sites located in the urban area of Divinópolis (Minas Gerais), southeastern Brazil, near iron and steel mills. The carcinogenic potency of priority PAHs relative to benzo[a]pyrene was estimated for a period of six months. Benzo[a]pyrene equivalents were 7.52 ng/m(3) for the study period. The estimated risk of lifetime lung cancer was 6.5 × 10(-4) . A model based on the diagnostic ratio and principal component analysis was applied for source apportionment. Considering the entire study period, the burning of biomass and fuel oil accounted for about 70% of the PAH profile. An inventory was performed during the monitoring period, with 37 companies representing major industries located in the urban area. The observations were consistent with the distribution of sources and indicated that the iron and steel sector was the largest contributor. Copyright © 2012 SETAC.

Further evaluation of quantitative structure--activity relationship models for the prediction of the skin sensitization potency of selected fragrance allergens.

PubMed

Patlewicz, Grace Y; Basketter, David A; Pease, Camilla K Smith; Wilson, Karen; Wright, Zoe M; Roberts, David W; Bernard, Guillaume; Arnau, Elena Giménez; Lepoittevin, Jean-Pierre

2004-02-01

Fragrance substances represent a very diverse group of chemicals; a proportion of them are associated with the ability to cause allergic reactions in the skin. Efforts to find substitute materials are hindered by the need to undertake animal testing for determining both skin sensitization hazard and potency. One strategy to avoid such testing is through an understanding of the relationships between chemical structure and skin sensitization, so-called structure-activity relationships. In recent work, we evaluated 2 groups of fragrance chemicals -- saturated aldehydes and alpha,beta-unsaturated aldehydes. Simple quantitative structure-activity relationship (QSAR) models relating the EC3 values [derived from the local lymph node assay (LLNA)] to physicochemical properties were developed for both sets of aldehydes. In the current study, we evaluated an additional group of carbonyl-containing compounds to test the predictive power of the developed QSARs and to extend their scope. The QSAR models were used to predict EC3 values of 10 newly selected compounds. Local lymph node assay data generated for these compounds demonstrated that the original QSARs were fairly accurate, but still required improvement. Development of these QSAR models has provided us with a better understanding of the potential mechanisms of action for aldehydes, and hence how to avoid or limit allergy. Knowledge generated from this work is being incorporated into new/improved rules for sensitization in the expert toxicity prediction system, deductive estimation of risk from existing knowledge (DEREK).

The lethality test used for estimating the potency of antivenoms against Bothrops asper snake venom: pathophysiological mechanisms, prophylactic analgesia, and a surrogate in vitro assay.

PubMed

Chacón, Francisco; Oviedo, Andrea; Escalante, Teresa; Solano, Gabriela; Rucavado, Alexandra; Gutiérrez, José María

2015-01-01

The potency of antivenoms is assessed by analyzing the neutralization of venom-induced lethality, and is expressed as the Median Effective Dose (ED50). The present study was designed to investigate the pathophysiological mechanisms responsible for lethality induced by the venom of Bothrops asper, in the experimental conditions used for the evaluation of the neutralizing potency of antivenoms. Mice injected with 4 LD50s of venom by the intraperitoneal route died within ∼25 min with drastic alterations in the abdominal organs, characterized by hemorrhage, increment in plasma extravasation, and hemoconcentration, thus leading to hypovolemia and cardiovascular collapse. Snake venom metalloproteinases (SVMPs) play a predominat role in lethality, as judged by partial inhibition by the chelating agent CaNa2EDTA. When venom was mixed with antivenom, there was a venom/antivenom ratio at which hemorrhage was significantly reduced, but mice died at later time intervals with evident hemoconcentration, indicating that other components in addition to SVMPs also contribute to plasma extravasation and lethality. Pretreatment with the analgesic tramadol did not affect the outcome of the neutralization test, thus suggesting that prophylactic (precautionary) analgesia can be introduced in this assay. Neutralization of lethality in mice correlated with neutralization of in vitro coagulant activity in human plasma. Copyright © 2014 Elsevier Ltd. All rights reserved.

Activation of peripheral blood mononuclear cells by dengue virus infection depotentiates balapiravir.

PubMed

Chen, Yen-Liang; Abdul Ghafar, Nahdiyah; Karuna, Ratna; Fu, Yilong; Lim, Siew Pheng; Schul, Wouter; Gu, Feng; Herve, Maxime; Yokohama, Fumiaki; Wang, Gang; Cerny, Daniela; Fink, Katja; Blasco, Francesca; Shi, Pei-Yong

2014-02-01

In a recent clinical trial, balapiravir, a prodrug of a cytidine analog (R1479), failed to achieve efficacy (reducing viremia after treatment) in dengue patients, although the plasma trough concentration of R1479 remained above the 50% effective concentration (EC(50)). Here, we report experimental evidence to explain the discrepancy between the in vitro and in vivo results and its implication for drug development. R1479 lost its potency by 125-fold when balapiravir was used to treat primary human peripheral blood mononuclear cells (PBMCs; one of the major cells targeted for viral replication) that were preinfected with dengue virus. The elevated EC(50) was greater than the plasma trough concentration of R1479 observed in dengue patients treated with balapiravir and could possibly explain the efficacy failure. Mechanistically, dengue virus infection triggered PBMCs to generate cytokines, which decreased their efficiency of conversion of R1479 to its triphosphate form (the active antiviral ingredient), resulting in decreased antiviral potency. In contrast to the cytidine-based compound R1479, the potency of an adenosine-based inhibitor of dengue virus (NITD008) was much less affected. Taken together, our results demonstrate that viral infection in patients before treatment could significantly affect the conversion of the prodrug to its active form; such an effect should be calculated when estimating the dose efficacious for humans.

Tuberculin purified protein derivative (PPD) immunoassay as an in vitro alternative assay for identity and confirmation of potency.

PubMed

Ho, Mei M; Kairo, Satnam K; Corbel, Michael J

2006-01-01

Tuberculin purified protein derivative (PPD) currently can only be standardised by delayed hypersensitivity skin reactions in sensitised guinea pigs. An in vitro dot blot immunoassay was developed for both identity and confirmation of potency estimation of PPD. Polyclonal antibodies (mainly IgG) were generated and immunoreacted with human, bovine and, to lesser extent, avian PPD preparations. Combining size exclusion chromatography (FPLC-SEC) and dot blot immunoassay, the results showed that PPD preparations were mixtures of very heterogeneous tuberculoproteins ranging in size from very large aggregates to very small degraded molecules. All individual fractions of PPD separated by size were immunoreactive, although those of the largest molecular sizes appeared the most immunoreactive in this in vitro dot blot immunoassay. This method is very sensitive and specific to tuberculoproteins and can be an in vitro alternative for the in vivo intradermal skin assay which uses guinea pigs for identity of PPD preparations. Although the capacity of PPD to elicit cell-mediated immune responses on intradermal testing has to be confirmed by in vivo assay, the dot blot immunoassay offers a rapid, sensitive and animal-free alternative to in vivo testing for confirming the identity of PPD preparations with appropriate potencies. This alternative assay would be particularly useful for national regulatory laboratories for confirming the data of manufacturers and thus reducing the use of animals.

Geohydrology, geochemistry, geothermal potency of Rianiate Toba Lake North Sumatera

NASA Astrophysics Data System (ADS)

Nainggolan, Juliper; Sitepu, Cristin; Pardede, Sanggam; Diantoro, Markus

2017-09-01

This research was performed to determine the potency of Rianiate’s geothermal an alternative of energy source and determine the types of geothermal that was begun with the position’s measurement by using GPS (Global Position System), and then the direct observation of chemical and physical properties such as pH, surface’s temperature, color etc. The following steps were taking sample in four different springs indicated by spring 1, spring 2, spring 3, and spring 4. The chemical nature was measured by titrimetry method by using AAS, XRD, and gas Chromathology. The calculating of temperature of subsurface has done by using geothermometer and sequentially followed by geothermal potency’s calculation. The position of four springs are located about N: 02° 31,852’ and E: 098° 44. 021’ where were average height from sea’s level is 958 m. The highest surface’s temperature is 80 °C and the temperature under soil is about 130.5 °C described the average of geothermal. The calculation of content of chloride, sulfate, bicarbonations revealed that the water can be categorized as chloride type. The trilateral diagram Na/1000 - K/100 - √Mg of hot water is in the regime of immature water. From the calculation of Indonesia’s Standardized Geotherm, it was obtained that the estimated reservoir potency of Rianiate geotherm is 2,68 MWe.

Assessment of the skin sensitization potency of eugenol and its dimers using a non-radioisotopic modification of the local lymph node assay.

PubMed

Takeyoshi, Masahiro; Noda, Shuji; Yamazaki, Shunsuke; Kakishima, Hiroshi; Yamasaki, Kanji; Kimber, Ian

2004-01-01

Allergic contact dermatitis is a serious health problem. There is a need to identify and characterize skin sensitization hazards, particularly with respect to relative potency, so that accurate risk assessments can be developed. For these purposes the murine local lymph node assay (LLNA) was developed. Here, we have investigated further a modi fi cation of this assay, non-radioisotopic LLNA, which in place of tritiated thymidine to measure lymph node cell proliferation employs incorporation of 5-bromo-2'-deoxyuridine. Using this method we have examined the skin sensitizing activity of eugenol, a known human contact allergen, and its dimers 2,2'-dihydroxyl-3,3'-dimethoxy-5,5'-diallyl-biphenyl (DHEA) and 4,5'-diallyl-2'-hydroxy-2,3'-dimethoxy phenyl ether (DHEB). Activity in the guinea pig maximization test (GPMT) also measured. On the basis of GPMT assays, eugenol was classified as a mild skin sensitizer, DHEA as a weak skin sensitizer and DHEB as an extreme skin sensitizer. In the non-radioisotopic LLNA all chemicals were found to give positive responses insofar as each was able to provoke a stimulation index (SI) of >or=3 at one or more test concentrations. The relative skin sensitizing potency of these chemicals was evaluated in the non-radioisotopic LLNA by derivation of an ec(3) value (the concentration of chemical required to provoke an SI of 3). The ec(3) values calculated were 25.1% for eugenol, >30% for DHEA and 2.3% for DHEB. Collectively these data suggest that assessments of relative potency deriving from non-radioisotopic LLNA responses correlate well with evaluations based on GPMT results. These investigations provide support for the proposal that the non-radioisotopic LLNA may serve as an effective alternative to the GPMT where there is a need to avoid the use of radioisotopes. Copyright 2004 John Wiley & Sons, Ltd.

Pharmacological characterization of receptor-activity-modifying proteins (RAMPs) and the human calcitonin receptor.

PubMed

Armour, S L; Foord, S; Kenakin, T; Chen, W J

1999-12-01

Receptor-activity-modifying proteins (RAMPs) are a family of single transmembrane domain proteins shown to be important for the transport and ligand specificity of the calcitonin gene-related peptide (CGRP) receptor. In this report, we describe the analysis of pharmacological properties of the human calcitonin receptor (hCTR) coexpressed with different RAMPs with the use of the Xenopus laevis melanophore expression system. We show that coexpression of RAMP3 with human calcitonin receptor changed the relative potency of hCTR to human calcitonin (hCAL) and rat amylin. RAMP1 and RAMP2, in contrast, had little effect on the change of hCTR potency to hCAL or rat amylin. When coexpressed with RAMP3, hCTR reversed the relative potency by a 3.5-fold loss in sensitivity to hCAL and a 19-fold increase in sensitivity to rat amylin. AC66, an inverse agonist, produced apparent simple competitive antagonism of hCAL and rat amylin, as indicated by linear Schild regressions. The potency of AC66 was changed in the blockade of rat amylin but not hCAL responses with RAMP3 coexpression. The mean pK(B) for AC66 to hCAL was 9.4 +/- 0.3 without RAMP3 and 9.45 +/- 0.07 with RAMP3. For the antagonism of AC66 to rat amylin, the pK(B) was 9.25 +/- 0.15 without RAMP3 and 8.2 +/- 0.35 with RAMP3. The finding suggests that RAMP3 might modify the active states of calcitonin receptor in such a way as to create a new receptor phenotype that is "amylin-like." Irrespective of the physiological association of the new receptor species, the finding that a coexpressed membrane protein can completely change agonist and antagonist affinities for a receptor raises implications for screening in recombinant receptor systems.

The actions of two sensory neuropeptides, substance P and calcitonin gene-related peptide, on the canine hepatic arterial and portal vascular beds.

PubMed Central

Withrington, P. G.

1992-01-01

1. The two peptides, calcitonin gene-related peptide (CGRP) and substance P (SP) were administered individually as bolus injections into the separately perfused hepatic arterial and portal vascular beds of the anaesthetized dog to assess their actions and relative molar potencies at these sites. 2. CGRP caused an immediate dose-related increase in hepatic arterial flow when injected close-arterially, reflecting a fall in resistance. This vasodilator effect was slightly increased by the prior administration of the selective beta 2-adrenoceptor antagonist, ICI 118,551. 3. On a molar basis, CGRP was more potent as an hepatic arterial vasodilator than the non-selective beta-adrenoceptor agonist, isoprenaline (Iso). 4. Intra-portal injection of CGRP also evoked hepatic arterial vasodilatation unaccompanied by other cardiovascular changes. 5. CGRP in doses up to 10 nmol had no effect on portal vascular resistance when administered intra-portally. 6. SP evoked a rapid, dose-related increase in hepatic arterial flow when injected intra-arterially. The molar ED50 for this hepatic vasodilatation was 40.2 fmol, significantly less than the ED50 for either CGRP or Iso. SP was the most potent hepatic arterial vasodilator yet examined. The vasodilator effect of SP was slightly potentiated by prior beta 2-adrenoceptor blockade. 7. SP caused hepatic arterial vasodilatation when administered by intra-portal injection; its absolute and relative potency was much reduced. 8. SP when injected intra-portally caused a graded increase in hepatic portal inflow resistance. The molar potency for this portal vasoconstriction was significantly greater than that for noradrenaline (NA); however, the maximum increase in portal resistance was significantly less to SP than to NA.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1384909

Associations between butane hash oil use and cannabis-related problems.

PubMed

Meier, Madeline H

2017-10-01

High-potency cannabis concentrates are increasingly popular in the United States, and there is concern that use of high-potency cannabis might increase risk for cannabis-related problems. However, little is known about the potential negative consequences of concentrate use. This study reports on associations between past-year use of a high-potency cannabis concentrate, known as butane hash oil (BHO), and cannabis-related problems. A sample of 821 college students were recruited to complete a survey about their health and behavior. Participants who had used cannabis in the past year (33%, n=273) completed questions about their cannabis use, including their use of BHO and cannabis-related problems in eight domains: physical dependence, impaired control, academic-occupational problems, social-interpersonal problems, self-care problems, self-perception, risk behavior, and blackouts. Approximately 44% (n=121) of past-year cannabis users had used BHO in the past year. More frequent BHO use was associated with higher levels of physical dependence (RR=1.8, p<0.001), impaired control (RR=1.3, p<0.001), cannabis-related academic/occupational problems (RR=1.5, p=0.004), poor self-care (RR=1.3, p=0.002), and cannabis-related risk behavior (RR=1.2, p=0.001). After accounting for sociodemographic factors, age of onset of cannabis use, sensation seeking, overall frequency of cannabis use, and frequency of other substance use, BHO use was still associated with higher levels of physical dependence (RR=1.2, p=0.014). BHO use is associated with greater physiological dependence on cannabis, even after accounting for potential confounders. Longitudinal research is needed to determine if cannabis users with higher levels of physiological dependence seek out BHO and/or if BHO use increases risk for physiological dependence. Copyright © 2017 Elsevier B.V. All rights reserved.

Prediction of preservative sensitization potential using surface marker CD86 and/or CD54 expression on human cell line, THP-1.

PubMed

Sakaguchi, Hitoshi; Miyazawa, Masaaki; Yoshida, Yukiko; Ito, Yuichi; Suzuki, Hiroyuki

2007-02-01

Preservatives are important components in many products, but have a history of purported allergy. Several assays [e.g., guinea pig maximization test (GPMT), local lymph node assay (LLNA)] are used to evaluate allergy potential of preservatives. We recently developed the human Cell Line Activation Test (h-CLAT), an in vitro skin sensitization test using human THP-1 cells. This test evaluates the augmentation of CD86 and CD54 expression, which are key events in the sensitization process, as an indicator of allergy following treatment with test chemical. Earlier, we found that a sub-toxic concentration was needed for the up-regulation of surface marker expression. In this study, we further evaluate the capability of h-CLAT to predict allergy potential using eight preservatives. Cytotoxicity was determined using propidium iodide with flow cytometry analysis and five doses that produce a 95, 85, 75, 65, and 50% cell viability were selected. If a material did not have any cytotoxicity at the highest technical dose (HTD), five doses are set using serial 1.3 dilutions of the HTD. The test materials used were six known allergic preservatives (e.g., methylchloroisothiazolinone/methylisothiazolinone, formaldehyde), and two non-allergic preservatives (methylparaben and 4-hydroxybenzoic acid). All allergic preservatives augmented CD86 and/or CD54 expression, indicating h-CLAT correctly identified the allergens. No augmentation was observed with the non-allergic preservatives; also correctly identified by h-CLAT. In addition, we report two threshold concentrations that may be used to categorize skin sensitization potency like the LLNA estimated concentration that yield a three-fold stimulation (EC3) value. These corresponding values are the estimated concentration which gives a relative fluorescence intensity (RFI) = 150 for CD86 and an RFI = 200 for CD54. These data suggest that h-CLAT, using THP-1 cells, may be able to predict the allergy potential of preservatives and possibility classify the potency of an allergen.

Environmental contamination and human exposure to dioxin-related compounds in e-waste recycling sites of developing countries.

PubMed

Tue, Nguyen Minh; Takahashi, Shin; Subramanian, Annamalai; Sakai, Shinichi; Tanabe, Shinsuke

2013-07-01

E-waste recycling using uncontrolled processes is a major source of dioxin-related compounds (DRCs), including not only the regulated polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) but also non-regulated brominated and mixed halogenated compounds (PBDD/Fs and PXDD/Fs). Various studies at informal e-waste recycling sites (EWRSs) in Asian developing countries found the soil contamination levels of PCDD/Fs from tens to ten thousand picogram TCDD-equivalents (TEQ) per gram and those of DL-PCBs up to hundreds of picogram TEQ per gram. The air concentration of PCDD/Fs was reported as high as 50 pg TEQ per m(3) in Guiyu, the largest Chinese EWRS. Non-regulated compounds also contributed substantially to the total DL toxicity of the DRC mixtures from e-waste, as evidenced by the high TEQ levels estimated for the currently identifiable PBDD/Fs as well as the large portion of unexplained bioassay-derived TEQ levels in soils/dusts from EWRSs. Considering the high exposure levels estimated for EWRS residents, especially children, comprehensive emission inventories of DRCs from informal e-waste recycling, the identities and toxic potencies of unidentified DRCs released, and their impacts on human health need to be investigated in future studies.

Aminomethyl-Derived Beta Secretase (BACE1) Inhibitors: Engaging Gly230 without an Anilide Functionality

PubMed Central

2016-01-01

A growing subset of β-secretase (BACE1) inhibitors for the treatment of Alzheimer’s disease (AD) utilizes an anilide chemotype that engages a key residue (Gly230) in the BACE1 binding site. Although the anilide moiety affords excellent potency, it simultaneously introduces a third hydrogen bond donor that limits brain availability and provides a potential metabolic site leading to the formation of an aniline, a structural motif of prospective safety concern. We report herein an alternative aminomethyl linker that delivers similar potency and improved brain penetration relative to the amide moiety. Optimization of this series identified analogues with an excellent balance of ADME properties and potency; however, potential drug–drug interactions (DDI) were predicted based on CYP 2D6 affinities. Generation and analysis of key BACE1 and CYP 2D6 crystal structures identified strategies to obviate the DDI liability, leading to compound 16, which exhibits robust in vivo efficacy as a BACE1 inhibitor. PMID:27997172

Glucose-responsive insulin by molecular and physical design

NASA Astrophysics Data System (ADS)

Bakh, Naveed A.; Cortinas, Abel B.; Weiss, Michael A.; Langer, Robert S.; Anderson, Daniel G.; Gu, Zhen; Dutta, Sanjoy; Strano, Michael S.

2017-10-01

The concept of a glucose-responsive insulin (GRI) has been a recent objective of diabetes technology. The idea behind the GRI is to create a therapeutic that modulates its potency, concentration or dosing relative to a patient's dynamic glucose concentration, thereby approximating aspects of a normally functioning pancreas. From the perspective of the medicinal chemist, the GRI is also important as a generalized model of a potentially new generation of therapeutics that adjust potency in response to a critical therapeutic marker. The aim of this Perspective is to highlight emerging concepts, including mathematical modelling and the molecular engineering of insulin itself and its potency, towards a viable GRI. We briefly outline some of the most important recent progress toward this goal and also provide a forward-looking viewpoint, which asks if there are new approaches that could spur innovation in this area as well as to encourage synthetic chemists and chemical engineers to address the challenges and promises offered by this therapeutic approach.

Beta-endorphin. Biological activity of synthetic analogs with analgesia inhibiting property in rat vas deferens and guinea pig ileum assays.

PubMed

Ho, C L; Li, C H

1985-03-01

Three synthetic analogs of human beta-endorphin (beta h-EP) (I, [Gln8, Gly31]-beta h-EP-Gly-Gly-NH2; II, [Arg9,12,24,28,29]-beta h-EP and III, [Cys11,26, Phe27, Gly31]-beta h-EP), which have been shown to possess potent inhibiting activity to beta h-EP-induced analgesia, were assayed in rat vas deferens and guinea pig ileum bioassay systems. In the rat vas deferens assay, relative potencies of these analogs were beta h-EP, 100; I, 30; II, 40; III, 1, whereas in the guinea pig ileum assay: beta h-EP, 100; I, 184; II, 81; III, 163. From previous studies on their analgesia potency in mice and opiate receptor-binding activity in rat brain membranes, their activity in rat vas deferens correlates well with the analgesic potency and the activity from guinea pig ileum assay shows good correlations with that from the opiate receptor-binding assay.

Glucose-responsive insulin by molecular and physical design.

PubMed

Bakh, Naveed A; Cortinas, Abel B; Weiss, Michael A; Langer, Robert S; Anderson, Daniel G; Gu, Zhen; Dutta, Sanjoy; Strano, Michael S

2017-09-22

The concept of a glucose-responsive insulin (GRI) has been a recent objective of diabetes technology. The idea behind the GRI is to create a therapeutic that modulates its potency, concentration or dosing relative to a patient's dynamic glucose concentration, thereby approximating aspects of a normally functioning pancreas. From the perspective of the medicinal chemist, the GRI is also important as a generalized model of a potentially new generation of therapeutics that adjust potency in response to a critical therapeutic marker. The aim of this Perspective is to highlight emerging concepts, including mathematical modelling and the molecular engineering of insulin itself and its potency, towards a viable GRI. We briefly outline some of the most important recent progress toward this goal and also provide a forward-looking viewpoint, which asks if there are new approaches that could spur innovation in this area as well as to encourage synthetic chemists and chemical engineers to address the challenges and promises offered by this therapeutic approach.

Characterizing Class‐Specific Exposure‐Viral Load Suppression Response of HIV Antiretrovirals Using A Model‐Based Meta‐Analysis

PubMed Central

Xu, Y; Li, YF; Zhang, D; Dockendorf, M; Tetteh, E; Rizk, ML; Grobler, JA; Lai, M‐T; Gobburu, J

2016-01-01

We applied model‐based meta‐analysis of viral suppression as a function of drug exposure and in vitro potency for short‐term monotherapy in human immunodeficiency virus type 1 (HIV‐1)‐infected treatment‐naïve patients to set pharmacokinetic targets for development of nonnucleoside reverse transcriptase inhibitors (NNRTIs) and integrase strand transfer inhibitors (InSTIs). We developed class‐specific models relating viral load kinetics from monotherapy studies to potency normalized steady‐state trough plasma concentrations. These models were integrated with a literature assessment of doses which demonstrated to have long‐term efficacy in combination therapy, in order to set steady‐state trough concentration targets of 6.17‐ and 2.15‐fold above potency for NNRTIs and InSTIs, respectively. Both the models developed and the pharmacokinetic targets derived can be used to guide compound selection during preclinical development and to predict the dose–response of new antiretrovirals to inform early clinical trial design. PMID:27171172

AFIR: A Dimensionless Potency Metric for Characterizing the Activity of Monoclonal Antibodies

PubMed Central

Ramakrishna, R

2017-01-01

For monoclonal antibody (mAb) drugs, soluble targets may accumulate several thousand fold after binding to the drug. Time course data of mAb and total target is often collected and, although free target is more closely related to clinical effect, it is difficult to measure. Therefore, mathematical models of this data are used to predict target engagement. In this article, a “potency factor” is introduced as an approximation for the model‐predicted target inhibition. This potency factor is defined to be the time‐Averaged Free target concentration to Initial target concentration Ratio (AFIR), and it depends on three key quantities: the average drug concentration at steady state; the binding affinity; and the degree of target accumulation. AFIR provides the intuition for how changes in dosing regimen and binding affinity affect target capture and AFIR can be used to predict the druggability of new targets and the expected benefits of more potent, second‐generation mAbs. PMID:28375563

Resorcinol-, catechol- and saligenin-based bronchodilating β2-agonists as inhibitors of human cholinesterase activity.

PubMed

Bosak, Anita; Knežević, Anamarija; Gazić Smilović, Ivana; Šinko, Goran; Kovarik, Zrinka

2017-12-01

We investigated the influence of bronchodilating β2-agonists on the activity of human acetylcholinesterase (AChE) and usual, atypical and fluoride-resistant butyrylcholinesterase (BChE). We determined the inhibition potency of racemate and enantiomers of fenoterol as a resorcinol derivative, isoetharine and epinephrine as catechol derivatives and salbutamol and salmeterol as saligenin derivatives. All of the tested compounds reversibly inhibited cholinesterases with K i constants ranging from 9.4 μM to 6.4 mM and had the highest inhibition potency towards usual BChE, but generally none of the cholinesterases displayed any stereoselectivity. Kinetic and docking results revealed that the inhibition potency of the studied compounds could be related to the size of the hydroxyaminoethyl chain on the benzene ring. The additional π-π interaction of salmeterol's benzene ring and Trp286 and hydrogen bond with His447 probably enhanced inhibition by salmeterol which was singled out as the most potent inhibitor of all the cholinesterases.

Characterization of species-related differences in the pharmacology of tachykinin NK receptors 1, 2 and 3.

PubMed

Leffler, Agnes; Ahlstedt, Ingela; Engberg, Susanna; Svensson, Arne; Billger, Martin; Oberg, Lisa; Bjursell, Magnus K; Lindström, Erik; von Mentzer, Bengt

2009-05-01

Tachykinin NK receptors (NKRs) differ to a large degree among species with respect to their affinities for small molecule antagonists. The aims of the present study were to clone NKRs from gerbil (NK2R and NK3R) and dog (NK1R, NK2R and NK3R) in which the sequence was previously unknown and to investigate the potency of several NKR antagonists at all known human, dog, gerbil and rat NKRs. The NKR protein coding sequences were cloned and expressed in CHO cells. The inhibitory concentrations of selective and non-selective NKR antagonists were determined by inhibition of agonist-induced mobilization of intracellular Ca2+. Receptor homology models were constructed based on the rhodopsin crystal structure to investigate and identify the antagonist binding sites and interaction points in the transmembrane (TM) regions of the NKRs. Data collected using the cloned dog NK1R confirmed that the dog NK1R displays similar pharmacology as the human and the gerbil NK1R, but differs greatly from the mouse and the rat NK1R. Despite species-related amino acid (AA) differences located close to the antagonist binding pocket of the NK2R, they did not affect the potency of the antagonists ZD6021 and saredutant. Two AA differences located close to the antagonist binding site of NK3R likely influence the NK3R antagonist potency, explaining the 3-10-fold decrease in potency observed for the rat NK3R. For the first time, detailed pharmacological experiments in vitro with cloned NKRs demonstrate that not only human, but also dog and gerbil NKR displays similar antagonist pharmacology while rat diverges significantly with respect to NK1R and NK3R.

Cocaine-like discriminative stimulus effects of "norepinephrine-preferring" monoamine releasers: time course and interaction studies in rhesus monkeys.

PubMed

Kohut, Stephen J; Jacobs, David S; Rothman, Richard B; Partilla, John S; Bergman, Jack; Blough, Bruce E

2017-12-01

The therapeutic potential of monoamine releasers with prominent dopaminergic effects is hindered by their high abuse liability. The present study examined the effects of several novel "norepinephrine (NE)-preferring" monoamine releasers relative to non-selective monoamine releasers, d-amphetamine and d-methamphetamine, in rhesus monkeys trained to discriminate cocaine. NE-preferring releasers were approximately 13-fold more potent for NE compared to dopamine release and ranged in potency for serotonin release (PAL-329 < l-methamphetamine < PAL-169). Adult rhesus macaques were trained to discriminate 0.4 mg/kg, IM cocaine on a 30-response fixed ratio schedule of food reinforcement. Substitution studies determined the extent to which test drugs produced cocaine-like discriminative stimulus effects and their time course. Drug interaction studies determined whether pretreatment with test drugs altered the discriminable effects of cocaine. Results show that cocaine, d-amphetamine, and d-methamphetamine dose-dependently substituted for cocaine with similar potencies. Among the "NE-preferring" releasers, PAL-329 and l-methamphetamine also dose-dependently substituted for cocaine but differed in potency. PAL-169 failed to substitute for cocaine up to a dose that disrupted responding. When administered prior to cocaine, only d-amphetamine and PAL-329 significantly shifted the cocaine dose-effect function leftward indicating enhancement of cocaine's discriminative stimulus effects. These data suggest that greater potency for NE relative to dopamine release (up to 13-fold) does not interfere with the ability of a monoamine releaser to produce cocaine-like discriminative effects but that increased serotonin release may have an inhibitory effect. Further characterization of these and other "NE-preferring" monoamine releasers should provide insight into their potential for the management of cocaine addiction.

Antigen Potency and Maximal Efficacy Reveal a Mechanism of Efficient T Cell Activation

PubMed Central

Wheeler, Richard J.; Zhang, Hao; Cordoba, Shaun-Paul; Peng, Yan-Chun; Chen, Ji-Li; Cerundolo, Vincenzo; Dong, Tao; Coombs, Daniel; van der Merwe, P. Anton

2014-01-01

T cell activation, a critical event in adaptive immune responses, follows productive interactions between T cell receptors (TCRs) and antigens, in the form of peptide-bound major histocompatibility complexes (pMHCs) on the surfaces of antigen-presenting-cells. Upon activation, T cells can lyse infected cells, secrete cytokines, such as interferon-γ (IFN-γ), and perform other effector functions with various efficiencies that directly depend on the binding parameters of the TCR-pMHC complex. The mechanism that relates binding parameters to the efficiency of activation of the T cell remains controversial; some studies suggest that the dissociation constant (KD) determines the response (the “affinity model”), whereas others suggest that the off-rate (koff) is critical (the “productive hit rate model”). Here, we used mathematical modeling to show that antigen potency, as determined by the EC50, the functional correlate that is used to support KD-based models, could not be used to discriminate between the affinity and productive hit rate models. Our theoretical work showed that both models predicted a correlation between antigen potency and KD, but only the productive hit rate model predicted a correlation between maximal efficacy (Emax) and koff. We confirmed the predictions made by the productive hit rate model in experiments with cytotoxic T cell clones and a panel of pMHC variants. Therefore, we suggest that the activity of an antigen is determined by both its potency and maximal efficacy. We discuss the implications of our findings to the practical evaluation of T cell activation, for example in adoptive immunotherapies, and relate our work to the pharmacological theory of dose-response. PMID:21653229

Estimating the impact of grouping misclassification on risk ...

EPA Pesticide Factsheets

Environmental health risk assessments of chemical mixtures that rely on component approaches often begin by grouping the chemicals of concern according to toxicological similarity. Approaches that assume dose addition typically are used for groups of similarly-acting chemicals and those that assume response addition are used for groups of independently acting chemicals. Grouping criteria for similarity can include a common adverse outcome pathway (AOP) and similarly shaped dose-response curves, with the latter used in the relative potency factor (RPF) method for estimating mixture response. Independence of toxic action is generally assumed if there is evidence that the chemicals act by different mechanisms. Several questions arise about the potential for misclassification error in the mixture risk prediction. If a common AOP has been established, how much error could there be if the same dose-response curve shape is assumed for all chemicals, when the shapes truly differ and, conversely, what is the error potential if different shapes are assumed when they are not? In particular, how do those concerns impact the choice of index chemical and uncertainty of the RPF-estimated mixture response? What is the quantitative impact if dose additivity is assumed when complete or partial independence actually holds and vice versa? These concepts and implications will be presented with numerical examples in the context of uncertainty of the RPF-estimated mixture response,

A luciferase reporter gene assay and aryl hydrocarbon receptor 1 genotype predict the LD{sub 50} of polychlorinated biphenyls in avian species

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manning, Gillian E., E-mail: gmann017@uottawa.ca; Environment Canada, National Wildlife Research Centre, Ottawa, ON, Canada K1A 0H3; Farmahin, Reza, E-mail: mfarm070@uottawa.ca

2012-09-15

Birds differ in sensitivity to the embryotoxic effects of polychlorinated biphenyls (PCBs), which complicates environmental risk assessments for these chemicals. Recent research has shown that the identities of amino acid residues 324 and 380 in the avian aryl hydrocarbon receptor 1 (AHR1) ligand binding domain (LBD) are primarily responsible for differences in avian species sensitivity to selected dibenzo-p-dioxins and furans. A luciferase reporter gene (LRG) assay was developed in our laboratory to measure AHR1-mediated induction of a cytochrome P450 1A5 reporter gene in COS-7 cells transfected with different avian AHR1 constructs. In the present study, the LRG assay was usedmore » to measure the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and PCBs 126, 77, 105 and 118 on luciferase activity in COS-7 cells transfected with AHR1 constructs representative of 86 avian species in order to predict their sensitivity to PCB-induced embryolethality and the relative potency of PCBs in these species. The results of the LRG assay indicate that the identity of amino acid residues 324 and 380 in the AHR1 LBD are the major determinants of avian species sensitivity to PCBs. The relative potency of PCBs did not differ greatly among AHR1 constructs. Luciferase activity was significantly correlated with embryolethality data obtained from the literature (R{sup 2} ≥ 0.87, p < 0.0001). Thus, the LRG assay in combination with the knowledge of a species' AHR1 LBD sequence can be used to predict PCB-induced embryolethality in potentially any avian species of interest without the use of lethal methods on a large number of individuals. -- Highlights: ► PCB embryolethality in birds can be predicted from a species' AHR1 genotype. ► The reporter gene assay is useful for predicting species sensitivity to PCBs. ► The relative potency of PCBs does not appear to differ between AHR1 genotypes. ► Contamination of PCB 105 and PCB 118 did not affect their relative potency values.« less

Potency control of modified live viral vaccines for veterinary use.

PubMed

Terpstra, C; Kroese, A H

1996-04-01

This paper reviews various aspects of efficacy, and methods for assaying the potency of modified live viral vaccines. The pros and cons of parametric versus non-parametric methods for analysis of potency assays are discussed and critical levels of protection, as determined by the target(s) of vaccination, are exemplified. Recommendations are presented for designing potency assays on master virus seeds and vaccine batches.

Potency control of modified live viral vaccines for veterinary use.

PubMed

Terpstra, C; Kroese, A H

1996-01-01

This paper reviews various aspects of efficacy, and methods for assaying the potency of modified live viral vaccines. The pros and cons of parametric versus non-parametric methods for analysis of potency assays are discussed and critical levels of protection, as determined by the target(s) of vaccination, are exemplified. Recommendations are presented for designing potency assays on master virus seeds and vaccine batches.

Comparative analysis of skin sensitization potency of acrylates (methyl acrylate, ethyl acrylate, butyl acrylate, and ethylhexyl acrylate) using the local lymph node assay.

PubMed

Dearman, Rebecca J; Betts, Catherine J; Farr, Craig; McLaughlin, James; Berdasco, Nancy; Wiench, Karin; Kimber, Ian

2007-10-01

There are currently available no systematic experimental data on the skin sensitizing properties of acrylates that are of relevance in occupational settings. Limited information from previous guinea-pig tests or from the local lymph node assay (LLNA) is available; however, these data are incomplete and somewhat contradictory. For those reasons, we have examined in the LLNA 4 acrylates: butyl acrylate (BA), ethyl acrylate (EA), methyl acrylate (MA), and ethylhexyl acrylate (EHA). The LLNA data indicated that all 4 compounds have some potential to cause skin sensitization. In addition, the relative potencies of these acrylates were measured by derivation from LLNA dose-response analyses of EC3 values (the effective concentration of chemical required to induce a threefold increase in proliferation of draining lymph node cells compared with control values). On the basis of 1 scheme for the categorization of skin sensitization potency, BA, EA, and MA were each classified as weak sensitizers. Using the same scheme, EHA was considered a moderate sensitizer. However, it must be emphasized that the EC3 value for this chemical of 9.7% is on the borderline between moderate (<10%) and weak (>10%) categories. Thus, the judicious view is that all 4 chemicals possess relatively weak skin sensitizing potential.

The role of non-covalent protein binding in skin sensitisation potency of chemicals.

PubMed

Aleksic, Maja; Thain, Emma; Gutsell, Stephen J; Pease, Camilla K; Basketter, David A

2007-01-01

Skin sensitisation is a delayed hypersensitivity reaction caused by repeated exposure to common natural and synthetic chemical allergens. It is thought that small chemical sensitisers (haptens) are required to form a strong irreversible bond with a self protein/peptide and generate an immunogenic hapten-protein complex in order to be recognised by the immune system and stimulate T cell proliferation. The sensitisers are usually electrophilic chemicals that are directly reactive with proteins or reactive intermediates (metabolites) of chemically inert compounds (prohaptens). Sensitising chemicals are also capable of weak, non-covalent association with proteins and there is an ongoing debate about the role of weak interactions of chemicals and proteins in the chemistry of allergy. The non-covalent interactions are reversible and thus have a major impact on skin/epidermal bioavailability of chemical/reactive metabolites. We investigated the relationship between the relative level of non-covalent association to a model protein and their relative potencies as determined by the EC3 values in the murine local lymph node assay (LLNA) for a number of chemicals. Using human serum albumin as a model protein, we determined that no observable relationship exists between the two parameters for the chemicals tested. Therefore, at least for this model protein, non-covalent interactions appear not to be a key determinant of allergen potency.

‘In-Format’ screening of a novel bispecific antibody format reveals significant potency improvements relative to unformatted molecules

PubMed Central

Scott, Martin J.; Lee, Jennifer A.; Wake, Matthew S.; Batt, Kelly V.; Wattam, Trevor A.; Hiles, Ian D.; Batuwangala, Thil D.; Ashman, Claire I.; Steward, Michael

2017-01-01

ABSTRACT Bispecific antibodies (BsAbs) are emerging as an important class of biopharmaceutical. The majority of BsAbs are created from conventional antibodies or fragments engineered into more complex configurations. A recurring challenge in their development, however, is the identification of components that are optimised for inclusion in the final format in order to deliver both efficacy and robust biophysical properties. Using a modular BsAb format, the mAb-dAb, we assessed whether an ‘in-format’ screening approach, designed to select format-compatible domain antibodies, could expedite lead discovery. Human nerve growth factor (NGF) was selected as an antigen to validate the approach; domain antibody (dAb) libraries were screened, panels of binders identified, and binding affinities and potencies compared for selected dAbs and corresponding mAb-dAbs. A number of dAbs that exhibited high potency (IC50) when assessed in-format were identified. In contrast, the corresponding dAb monomers had ∼1000-fold lower potency than the formatted dAbs; such dAb monomers would therefore have been omitted from further characterization. Subsequent stoichiometric analyses of mAb-dAbs bound to NGF, or an additional target antigen (vascular endothelial growth factor), suggested different target binding modes; this indicates that the observed potency improvements cannot be attributed simply to an avidity effect offered by the mAb-dAb format. We conclude that, for certain antigens, screening naïve selection outputs directly in-format enables the identification of a subset of format-compatible dAbs, and that this offers substantial benefits in terms of molecular properties and development time. PMID:27786601

Critical elements in the development of cell therapy potency assays for ischemic conditions.

PubMed

Porat, Yael; Abraham, Eytan; Karnieli, Ohad; Nahum, Sagi; Woda, Juliana; Zylberberg, Claudia

2015-07-01

A successful potency assay for a cell therapy product (CTP) used in the treatment of ischemic conditions should quantitatively measure relevant biological properties that predict therapeutic activity. This is especially challenging because of numerous degrees of complexity stemming from factors that include a multifactorial complex mechanism of action, cell source, inherent cell characteristics, culture method, administration mode and the in vivo conditions to which the cells are exposed. The expected biological function of a CTP encompasses complex interactions that range from a biochemical, metabolic or immunological activity to structural replacement of damaged tissue or organ. Therefore, the requirements for full characterization of the active substance with respect to biological function could be taxing. Moreover, the specific mechanism of action is often difficult to pinpoint to a specific molecular entity; rather, it is more dependent on the functionality of the cellular components acting in a in a multifactorial fashion. In the case of ischemic conditions, the cell therapy mechanism of action can vary from angiogenesis, vasculogenesis and arteriogenesis that may activate different pathways and clinical outcomes. The CTP cellular attributes with relation to the suggested mechanism of action can be used for the development of quantitative and reproducible analytical potency assays. CTPs selected and released on the basis of such potency assays should have the highest probability of providing meaningful clinical benefit for patients. This White Paper will discuss and give examples for key elements in the development of a potency assay for treatment of ischemic disorders treated by the use of CTPs. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Steroid-like compounds in Chinese medicines promote blood circulation via inhibition of Na+/K+-ATPase

PubMed Central

Chen, Ronald JY; Chung, Tse-yu; Li, Feng-yin; Yang, Wei-hung; Jinn, Tzyy-rong; Tzen, Jason TC

2010-01-01

Aim: To examine if steroid-like compounds found in many Chinese medicinal products conventionally used for the promotion of blood circulation may act as active components via the same molecular mechanism triggered by cardiac glycosides, such as ouabain. Methods: The inhibitory potency of ouabain and the identified steroid-like compounds on Na+/K+-ATPase activity was examined and compared. Molecular modeling was exhibited for the docking of these compounds to Na+/K+-ATPase. Results: All the examined steroid-like compounds displayed more or less inhibition on Na+/K+-ATPase, with bufalin (structurally almost equivalent to ouabain) exhibiting significantly higher inhibitory potency than the others. In the pentacyclic triterpenoids examined, ursolic acid and oleanolic acid were moderate inhibitors of Na+/K+-ATPase, and their inhibitory potency was comparable to that of ginsenoside Rh2. The relatively high inhibitory potency of ursolic acid or oleanolic acid was due to the formation of a hydrogen bond between its carboxyl group and the Ile322 residue in the deep cavity close to two K+ binding sites of Na+/K+-ATPase. Moreover, the drastic difference observed in the inhibitory potency of ouabain, bufalin, ginsenoside Rh2, and pentacyclic triterpenoids is ascribed mainly to the number of hydrogen bonds and partially to the strength of hydrophobic interaction between the compounds and residues around the deep cavity of Na+/K+-ATPase. Conclusion: Steroid-like compounds seem to contribute to therapeutic effects of many cardioactive Chinese medicinal products. Chinese herbs, such as Prunella vulgaris L, rich in ursolic acid, oleanolic acid and their glycoside derivatives may be adequate sources for cardiac therapy via effective inhibition on Na+/K+-ATPase. PMID:20523340

Highly purified hexachlorobenzene induces cytochrome P4501A in primary cultures of chicken embryo hepatocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mundy, Lukas J.; Environment Canada, National Wildlife Research Centre, Ottawa, Ontario; Jones, Stephanie P.

Some uncertainty exists regarding the purity of hexachlorobenzene (HCB) used in past toxicity studies. It has been suggested that reported toxic and biochemical effects initially attributed to HCB exposure may have actually been elicited by contamination of HCB by polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Herein, primary cultures of chicken embryo hepatocytes (CEH) were used to compare the potencies of two lots of reagent-grade hexachlorobenzene (HCB-old [HCB-O] and HCB-new [HCB-N]), highly purified HCB (HCB-P) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as inducers of ethoxyresorufin O-deethylase (EROD) activity, cytochrome P4501A4 (CYP1A4) messenger ribonucleic acid (mRNA) and CYP1A5 mRNA. The study also compared themore » EROD- and CYP1A4/5 mRNA-inducing potencies of HCB to the potencies of two mono-ortho substituted polychlorinated biphenyls (PCBs), 2,3,3',4,4'-pentachlorobiphenyl (PCB 105) and 2,3'4,4',5-pentachlorobiphenyl (PCB 118). HCB-O, HCB-N and HCB-P all induced EROD activity and up-regulated CYP1A4 and CYP1A5 mRNAs. Induction was not caused by contamination of HCB with PCDDs or PCDFs. Based upon a comparison of the EC{sub 50} and EC{sub threshold} values for EROD and CYP1A4/5 mRNA concentration-response curves, the potency of HCB relative to the potency of TCDD was 0.0001, and was similar to that of PCB 105 and PCB 118. The maximal EROD activity and CYP1A4/5 mRNA expression differed greatly between HCB and TCDD, and may contribute to an overestimation of the ReP value calculated for highly purified HCB.« less

Reproducibility of effects of homeopathically potentised gibberellic acid on the growth of Lemna gibba L. in a randomised and blinded bioassay.

PubMed

Majewsky, Vera; Scherr, Claudia; Arlt, Sebastian Patrick; Kiener, Jonas; Frrokaj, Kristina; Schindler, Tobias; Klocke, Peter; Baumgartner, Stephan

2014-04-01

Reproducibility of basic research investigations in homeopathy is challenging. This study investigated if formerly observed effects of homeopathically potentised gibberellic acid (GA3) on growth of duckweed (Lemna gibba L.) were reproducible. Duckweed was grown in potencies (14x-30x) of GA3 and one time succussed and unsuccussed water controls. Outcome parameter area-related growth rate was determined by a computerised image analysis system. Three series including five independent blinded and randomised potency experiments (PE) each were carried out. System stability was controlled by three series of five systematic negative control (SNC) experiments. Gibbosity (a specific growth state of L. gibba) was investigated as possibly essential factor for reactivity of L. gibba towards potentised GA3 in one series of potency and SNC experiments, respectively. Only in the third series with gibbous L. gibba L. we observed a significant effect (p = 0.009, F-test) of the homeopathic treatment. However, growth rate increased in contrast to the former study, and most biologically active potency levels differed. Variability in PE was lower than in SNC experiments. The stability of the experimental system was verified by the SNC experiments. Gibbosity seems to be a necessary condition for reactivity of L. gibba to potentised GA3. Further still unknown conditions seem to govern effect direction and the pattern of active and inactive potency levels. When designing new reproducibility studies, the physiological state of the test organism must be considered. Variability might be an interesting parameter to investigate effects of homeopathic remedies in basic research. Copyright © 2014 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

Potency under pressure: the impact of hydrostatic pressure on antigenic properties of influenza virus hemagglutinin.

PubMed

Eichelberger, Schafer L; Sultana, Ishrat; Gao, Jin; Getie-Kebtie, Melkamu; Alterman, Michail; Eichelberger, Maryna C

2013-11-01

Influenza vaccines are effective in protecting against illness and death caused by this seasonal pathogen. The potency of influenza vaccines is measured by single radial immunodiffusion (SRID) assay that quantifies antigenic forms of hemagglutinin (HA). Hydrostatic pressure results in loss of binding of influenza virus to red blood cells, but it is not known whether this infers loss of potency. Our goal was to determine the impact of pressure on HA antigenic structure. Viruses included in the 2010-2011 trivalent influenza vaccine were subjected to increasing number of cycles at 35,000 psi in a barocycler, and the impact of this treatment measured by determining hemagglutination units (HAU) and potency. Potency was assessed by SRID and immunogenicity in mice. After 25 cycles of pressure, the potency measured by SRID assay was below the limit of quantification for the H1N1 and B viruses used in our study, while the H3N2 component retained some potency that was lost after 50 pressure cycles. Pressure treatment also resulted in loss of HAU, but this did not strictly correlate with the potency value. Curiously, loss of potency was abrogated when influenza A, but not B, antigens were exposed to pressure in chicken egg allantoic fluid. Protection against pressure appeared to be mediated by specific interactions because addition of bovine serum albumin did not have the same effect. Our results show that pressure-induced loss of potency is strain dependent and suggests that pressure treatment may be useful for identifying vaccine formulations that improve HA stability. Published 2013. This article is U.S. Government work and in the public domain in the USA.

The comparative performance of the single intradermal test and the single intradermal comparative tuberculin test in Irish cattle, using tuberculin PPD combinations of differing potencies.

PubMed

Good, M; Clegg, T A; Costello, E; More, S J

2011-11-01

In national bovine tuberculosis (BTB) control programmes, testing is generally conducted using a single source of bovine purified protein derivative (PPD) tuberculin. Alternative tuberculin sources should be identified as part of a broad risk management strategy as problems of supply or quality cannot be discounted. This study was conducted to compare the impact of different potencies of a single bovine PPD tuberculin on the field performance of the single intradermal comparative tuberculin test (SICTT) and single intradermal test (SIT). Three trial potencies of bovine PPD tuberculin, as assayed in naturally infected bovines, namely, low (1192IU/dose), normal (6184IU/dose) and high (12,554IU/dose) were used. Three SICTTs (using) were conducted on 2102 animals. Test results were compared based on reactor-status and changes in skin-thickness at the bovine tuberculin injection site. There was a significant difference in the number of reactors detected using the high and low potency tuberculins. In the SICTT, high and low potency tuberculin detected 40% more and 50% fewer reactors, respectively, than normal potency tuberculin. Furthermore, use of the low potency tuberculin in the SICTT failed to detect 20% of 35 animals with visible lesions, and in the SIT 11% of the visible lesion animals would have been classified as negative. Tuberculin potency is critical to the performance of both the SICTT and SIT. Tuberculin of different potencies will affect reactor disclosure rates, confounding between-year or between-country comparisons. Independent checks of tuberculin potency are an important aspect of quality control in national BTB control programmes. Copyright © 2011 Elsevier Ltd. All rights reserved.

Theoretical study of the thermodynamics of the mechanisms underlying antiradical activity of cinnamic acid derivatives.

PubMed

Amić, Ana; Marković, Zoran; Klein, Erik; Dimitrić Marković, Jasmina M; Milenković, Dejan

2018-04-25

The role of antiradical moieties (catechol, guaiacyl and carboxyl group) and molecular conformation in antioxidative potency of dihydrocaffeic acid (DHCA) and dihydroferulic acid (DHFA) was investigated by density functional theory (DFT) method. The thermodynamic preference of different reaction paths of double (2H + /2e - ) free radical scavenging mechanisms was estimated. Antiradical potency of DHCA and DHFA was compared with that exerted by their unsaturated analogs - caffeic acid (CA) and ferulic acid (FA). Cis/trans and anti-isomers of studied cinnamic acid derivatives may scavenge free radicals via double processes by involvement of catechol or guaiacyl moiety. Carboxyl group of syn-isomers may also participate in the inactivation of free radicals. Gibbs free energies of reactions with various free radicals indicate that syn-DHCA and syn-DHFA, colon catabolites that could be present in systemic circulation in low μM concentrations, have a potential to contribute to health benefits by direct free radical scavenging. Copyright © 2017 Elsevier Ltd. All rights reserved.

Response surface methodology to simplify calculation of wood energy potency from tropical short rotation coppice species

NASA Astrophysics Data System (ADS)

Haqiqi, M. T.; Yuliansyah; Suwinarti, W.; Amirta, R.

2018-04-01

Short Rotation Coppice (SRC) system is an option to provide renewable and sustainable feedstock in generating electricity for rural area. Here in this study, we focussed on application of Response Surface Methodology (RSM) to simplify calculation protocols to point out wood chip production and energy potency from some tropical SRC species identified as Bauhinia purpurea, Bridelia tomentosa, Calliandra calothyrsus, Fagraea racemosa, Gliricidia sepium, Melastoma malabathricum, Piper aduncum, Vernonia amygdalina, Vernonia arborea and Vitex pinnata. The result showed that the highest calorific value was obtained from V. pinnata wood (19.97 MJ kg-1) due to its high lignin content (29.84 %, w/w). Our findings also indicated that the use of RSM for estimating energy-electricity of SRC wood had significant term regarding to the quadratic model (R2 = 0.953), whereas the solid-chip ratio prediction was accurate (R2 = 1.000). In the near future, the simple formula will be promising to calculate energy production easily from woody biomass, especially from SRC species.

Cannabis-induced psychosis associated with high potency "wax dabs".

PubMed

Pierre, Joseph M; Gandal, Michael; Son, Maya

2016-04-01

With mounting evidence that the risk of cannabis-induced psychosis may be related to both dose and potency of tetrahydrocannbinol (THC), increasing reports of psychosis associated with cannabinoids containing greater amounts of THC are anticipated. We report two cases of emergent psychosis after using a concentrated THC extract known as cannabis "wax," "oil," or "dabs" raising serious concerns about its psychotic liability. Although "dabbing" with cannabis wax is becoming increasingly popular in the US for both recreational and "medicinal" intentions, our cases raise serious concerns about its psychotic liability and highlight the importance of understanding this risk by physicians recommending cannabinoids for purported medicinal purposes. Published by Elsevier B.V.

Methods for the Quality Control of Inactivated Poliovirus Vaccines.

PubMed

Wilton, Thomas

2016-01-01

Inactivated poliovirus vaccine (IPV) plays an instrumental role in the Global Poliovirus Eradication Initiative (GPEI). The quality of IPV is controlled by assessment of the potency of vaccine batches. The potency of IPV can be assessed by both in vivo and in vitro methods. In vitro potency assessment is based upon the assessment of the quantity of the D-Antigen (D-Ag) units in an IPV. The D-Ag unit is used as a measure of potency as it is largely expressed on native infectious virions and is the protective immunogen. The most commonly used in vitro test is the indirect ELISA which is used to ensure consistency throughout production.A range of in vivo assays have been developed in monkeys, chicks, guinea pigs, mice, and rats to assess the potency of IPV. All are based on assessment of the neutralizing antibody titer within the sera of the respective animal model. The rat potency test has become the favored in vivo potency test as it shows minimal variation between laboratories and the antibody patterns of rats and humans are similar. With the development of transgenic mice expressing the human poliovirus receptor, immunization-challenge tests have been developed to assess the potency of IPVs. This chapter describes in detail the methodology of these three laboratory tests to assess the quality of IPVs.

Genetic differences in osteogenic differentiation potency in the thoracic ossification of the ligamentum flavum under cyclic mechanical stress.

PubMed

Ning, Shanglong; Chen, Zhongqiang; Fan, Dongwei; Sun, Chuiguo; Zhang, Chi; Zeng, Yan; Li, Weishi; Hou, Xiaofei; Qu, Xiaochen; Ma, Yunlong; Yu, Huilei

2017-01-01

Mechanical stress and genetic factors play important roles in the occurrence of thoracic ossification of ligament flavum (TOLF), which can occur at one, two, or multiple levels of the spine. It is unclear whether single- and multiple-level TOLF differ in terms of osteogenic differentiation potency and osteogenesis-related gene expression under cyclic mechanical stress. This was addressed in the present study using patients with non‑TOLF and single‑ and multiple‑level TOLF (n=8 per group). Primary ligament cells were cultured and osteogenesis was induced by application of cyclic mechanical stress. Osteogenic differentiation was assessed by evaluating alkaline phosphatase (ALP) activity and the mRNA and protein expression of osteogenesis‑related genes, including ALP, bone morphogenetic protein 2 (BMP2), Runt‑related transcription factor‑2 (Runx‑2), osterix, osteopontin (OPN) and osteocalcin. The application of cyclic mechanical stress resulted in higher ALP activity in the multiple‑level than in the single‑level TOLF group, whereas no changes were observed in the non‑TOLF group. The ALP, BMP2, OPN and osterix mRNA levels were higher in the multiple‑level as compared to the single‑level TOLF group, and the levels of all osteogenesis-related genes, apart from Runx2, were higher in the multiple‑level as compared to the non‑TOLF group. The osterix and ALP protein levels were higher in the multiple‑level TOLF group than in the other 2 groups, and were increased with the longer duration of stress. These results highlight the differences in osteogenic differentiation potency between single‑ and multiple‑level TOLF that may be related to the different pathogenesis and genetic background.

U.S. EPA health assessment for diesel engine exhaust: a review.

PubMed

Ris, Charles

2007-01-01

In 2002 the U.S. Environmental Protection Agency (EPA) released a Health assessment Document for Diesel Engine Exhaust. The objective of this assessment was to examine the possible health hazards associated with exposure to diesel engine exhaust (DE). The assessment concludes that long-term inhalation exposure is likely to pose a lung cancer hazard to humans as inferred from epidemiologic and certain animal studies. Estimation of cancer potency from available epidemiology studies was not attempted because of the absence of a confident cancer dose-response and animal studies were not judged appropriate for cancer potency estimation. A noncancer chronic human health hazard is inferred from rodent studies which show dose-dependent inflammation and histopathology in the rat lung. For these noncancer effects a safe exposure concentration for humans was estimated. Short-term exposures were noted to cause irritation and inflammatory symptoms of a transient nature, these being highly variable across an exposed population. The assessment also indicates that there is emerging evidence for the exacerbation of existing allergies and asthma symptoms; however, as of 2002 the data were inadequate for quantitative dose-response analysis. The assessment conclusions are based on studies that used exposures from engines built prior to the mid 1990s. More recent engines without high-efficiency particle traps would be expected to have exhaust emissions with similar characteristics. With additional cancer epidemiology studies expected in 2007-2008, and a growing body of evidence for allergenicity and cardiovascular effects, future health assessments will have an expanded health effects data base to evaluate.

Discovery of a Prefusion Respiratory Syncytial Virus F-Specific Monoclonal Antibody That Provides Greater In Vivo Protection than the Murine Precursor of Palivizumab.

PubMed

Zhao, Min; Zheng, Zi-Zheng; Chen, Man; Modjarrad, Kayvon; Zhang, Wei; Zhan, Lu-Ting; Cao, Jian-Li; Sun, Yong-Peng; McLellan, Jason S; Graham, Barney S; Xia, Ning-Shao

2017-08-01

Palivizumab, a humanized murine monoclonal antibody that recognizes antigenic site II on both the prefusion (pre-F) and postfusion (post-F) conformations of the respiratory syncytial virus (RSV) F glycoprotein, is the only prophylactic agent approved for use for the treatment of RSV infection. However, its relatively low neutralizing potency and high cost have limited its use to a restricted population of infants at high risk of severe disease. Previously, we isolated a high-potency neutralizing antibody, 5C4, that specifically recognizes antigenic site Ø at the apex of the pre-F protein trimer. We compared in vitro and in vivo the potency and protective efficacy of 5C4 and the murine precursor of palivizumab, antibody 1129. Both antibodies were synthesized on identical murine backbones as either an IgG1 or IgG2a subclass and evaluated for binding to multiple F protein conformations, in vitro inhibition of RSV infection and propagation, and protective efficacy in mice. Although 1129 and 5C4 had similar pre-F protein binding affinities, the 5C4 neutralizing activity was nearly 50-fold greater than that of 1129 in vitro In BALB/c mice, 5C4 reduced the peak titers of RSV 1,000-fold more than 1129 did in both the upper and lower respiratory tracts. These data indicate that antibodies specific for antigenic site Ø are more efficacious at preventing RSV infection than antibodies specific for antigenic site II. Our data also suggest that site Ø-specific antibodies may be useful for the prevention or treatment of RSV infection and support the use of the pre-F protein as a vaccine antigen. IMPORTANCE There is no vaccine yet available to prevent RSV infection. The use of the licensed antibody palivizumab, which recognizes site II on both the pre-F and post-F proteins, is restricted to prophylaxis in neonates at high risk of severe RSV disease. Recommendations for using passive immunization in the general population or for therapy in immunocompromised persons with persistent infection is limited because of cost, determined from the high doses needed to compensate for its relatively low neutralizing potency. Prior efforts to improve the in vitro potency of site II-specific antibodies did not translate to significant in vivo dose sparing. We isolated a pre-F protein-specific, high-potency neutralizing antibody (5C4) that recognizes antigenic site Ø and compared its efficacy to that of the murine precursor of palivizumab (antibody 1129) matched for isotype and pre-F protein binding affinities. Our findings demonstrate that epitope specificity is an important determinant of antibody neutralizing potency, and defining the mechanisms of neutralization has the potential to identify improved products for the prevention and treatment of RSV infection. Copyright © 2017 American Society for Microbiology.

Förster resonance energy transfer competitive displacement assay for human soluble epoxide hydrolase

PubMed Central

Lee, Kin Sing Stephen; Morisseau, Christophe; Yang, Jun; Wang, Peng; Hwang, Sung Hee; Hammock, Bruce D.

2013-01-01

The soluble epoxide hydrolase (sEH), responsible for the hydrolysis of various fatty acid epoxides to their corresponding 1,2-diols, is becoming an attractive pharmaceutical target. These fatty acid epoxides, particularly epoxyeicosatrienoic acids (EETs), play an important role in human homeostatic and inflammation processes. Therefore, inhibition of human sEH, which stabilizes EETs in vivo, brings several beneficial effects to human health. Although there are several catalytic assays available to determine the potency of sEH inhibitors, measuring the in vitro inhibition constant (Ki) for these inhibitors using catalytic assay is laborious. In addition, koff, which has been recently suggested to correlate better with the in vivo potency of inhibitors, has never been measured for sEH inhibitors. To better measure the potency of sEH inhibitors, a reporting ligand, 1-(adamantan-1-yl)-3-(1-(2-(7-hydroxy-2-oxo-2H-chromen-4-yl)acetyl) piperidin-4-yl)urea (ACPU), was designed and synthesized. With ACPU, we have developed a Förster resonance energy transfer (FRET)-based competitive displacement assay using intrinsic tryptophan fluorescence from sEH. In addition, the resulting assay allows us to measure the Ki values of very potent compounds to the picomolar level and to obtain relative koff values of the inhibitors. This assay provides additional data to evaluate the potency of sEH inhibitors. PMID:23219719

In vitro versus in vivo concordance: a case study of the replacement of an animal potency test with an immunochemical assay.

PubMed

Schofield, T

2002-01-01

Early in its development, the potency of Merck's recombinant hepatitis B vaccine, RECOMBIVAX HB, was monitored using an assay performed in mice. A specification was determined to be the lowest potency which induced acceptable response in clinical trials. As a post-licensing commitment, Merck was asked to replace its mouse potency assay with an in vitro procedure for product release in the US market. Early studies with a commercial enzyme immunoassay (EIA) yielded highly variable results. That assay, combined with a sample pretreatment step, proved more dependable and predictive of potency in the mouse assay. Based on measurements made on manufactured materials, combined with experiments contrived to yield a wide range of reactivity in the two assays, concordance was established between the EIA and the mouse potency assay. This concordance was used to calibrate a specification for the in vitro assay that is predictive of a satisfactory response in vivo. Data from clinical trials established a correspondence between human immunogenicity and these potency markers.

Planning of dairy farm and dairy plant based ecotourism

NASA Astrophysics Data System (ADS)

Sarnyoto, A. S.; Tama, I. P.; Tantrika, C. F. M.

2017-06-01

One of a dairy production company producing pasteurized milk and yoghurt drink, whose brand has widely known in East Java, has a factory plant in Batu City, one of tourism destinations in Indonesia. Behind the factory plant, there is a vacant land with an estimated total area of 2.3 ha and a vacant cowshed which had not been used for cattle ranching. Because of that, the company planned to develop the vacant land as a dairy farm and plant based ecotourism. In addition, dairy farm and dairy plant based tourism attractions are still rarely found in Batu. Thus, the first aim of this study was to analyse the potencies of the company that related to future plans of ecotourism built. The second aim was to set up the strategies that can be done in order to actualize the ecotourism project. The next aim was to plan the ecotourism, especially the facilities planning and the facilities arrangement on the vacant land. Strategic management approach was used to analyse the potencies and to determine the strategies. To select the proper facilities, tourists were asked to give appraisal by using questionnaire. Appraisal result was mapped onto four quadrants spatial map to see advantages and shortcomings of each facility along with choosing the right facilities to be built. Those facilities and tourist activities were compared with ecotourism criteria to make sure that the facilities were appropriate to provide not only entertainment but also ecotourism function. To arrange the chosen facilities, the step in Systematic Layout Planning were conducted to generate a propose layout of facilities arrangement. Based on potencies analysis, in Internal-External matrix, the company current position was on quadrant 2 (grow and build), with the most appropriate strategy was intensive or integrative. The proposed strategies were to build the new infrastructure, to renovate cowshed, and to add new tourism facilities on the land. There were 11 selected facilities based on MDS. Moreover, based on SLP, a facility layout had been designed and been proposed to be built on the vacant land behind the factory as the new ecotourism destination.

Evaluation of sensory irritation of delta3-carene and turpentine, and acceptable levels of monoterpenes in occupational and indoor environment.

PubMed

Kasanen, J P; Pasanen, A L; Pasanen, P; Liesivuori, J; Kosma, V M; Alarie, Y

1999-05-28

The standard mouse bioassay was used for obtaining the RD50 (i.e., the concentration that causes a 50% decrease in respiratory frequency) and for estimating the irritation properties of d-delta3-carene (i.e., (+)-delta3-carene) and commercial turpentine. The chemicals studied possess mainly sensory irritation properties similar to the previously studied monoterpenes, pinenes. The irritation potency of d-delta3-carene (RD50 = 1345 ppm) was almost equal to that of d-pinenes. Thus, d-delta3-carene was about four times more potent as a sensory irritant than I-beta-pinene, whereas the difference with I-alpha-pinene was more marked; as a sensory irritant, I-alpha-pinene is almost inactive. Based on sensory irritation potency and physicochemical and structural properties of pinenes and delta3-carene, the potency of a closely related monoterpene, limonene, is discussed. For commercial turpentine, a mixture of monoterpenes (mainly d-delta3-carene, I-beta-pinene, alpha-pinenes, and limonenes), the RD50 (1173 ppm) was the same order of magnitude as those of d-pinenes and d-delta3-carene. Apparently, d-monoterpenes are responsible for the sensory irritation caused by turpentine. In the wood industry and in the indoor air of nonindustrial environments, monoterpenes are thought to be one of the causative agents for irritation symptoms. The occupational exposure limit (OEL) of turpentine (100 ppm in Finland and the United States) is also used for individual monoterpenes, excluding limonene. Using results from this and our previous study, proposed OELs and recommended indoor levels (RILs) for selected monoterpenes and turpentine were determined based on their RD50 values. According to our studies, the present OEL of turpentine (100 ppm; 560 mg/m3) in Finland and in the United States seems to be suitable only for I-pinenes. For d-monoterpenes and turpentine, an OEL about three times lower is suggested. Our results show that recommended indoor levels (RILs) for monoterpenes are high compared to the concentrations measured indoors in nonindustrial environments. Thus, it is very unlikely that monoterpenes alone can cause irritation symptoms in homes or offices under normal conditions.

Supplement to the Carcinogenic Potency Database (CPDB): results of animal bioassays published in the general literature in 1993 to 1994 and by the National Toxicology Program in 1995 to 1996.

PubMed Central

Gold, L S; Manley, N B; Slone, T H; Rohrbach, L

1999-01-01

The Carcinogenic Potency Database (CPDB) is a systematic and unifying analysis of results of chronic, long-term cancer tests. This paper presents a supplemental plot of the CPDB, including 513 experiments on 157 test compounds published in the general literature in 1993 and 1994 and in Technical Reports of the National Toxicology Program in 1995 and 1996. The plot standardizes the experimental results (whether positive or negative for carcinogenicity), including qualitative data on strain, sex, route of compound administration, target organ, histopathology, and author's opinion and reference to the published paper, as well as quantitative data on carcinogenic potency, statistical significance, tumor incidence, dose-response curve shape, length of experiment, duration of dosing, and dose rate. A numerical description of carcinogenic potency, the TD(subscript)50(/subscript), is estimated for each set of tumor incidence data reported. When added to the data published earlier, the CPDB now includes results of 5,620 experiments on 1,372 chemicals that have been reported in 1,250 published papers and 414 National Cancer Institute/National Toxicology Program Technical Reports. The plot presented here includes detailed analyses of 25 chemicals tested in monkeys for up to 32 years by the National Cancer Institute. Half the rodent carcinogens that were tested in monkeys were not carcinogenic, despite usually strong evidence of carcinogenicity in rodents and/or humans. Our analysis of possible explanatory factors indicates that this result is due in part to the fact that the monkey studies lacked power to detect an effect compared to standard rodent bioassays. Factors that contributed to the lack of power are the small number of animals on test; a stop-exposure protocol for model rodent carcinogens; in a few cases, toxic doses that resulted in stoppage of dosing or termination of the experiment; and in a few cases, low doses administered to monkeys or early termination of the experiment even though the doses were not toxic. Among chemicals carcinogenic in both monkeys and rodents, there is some support for target site concordance, but it is primarily restricted to liver tumors. Potency values are highly correlated between rodents and monkeys. The plot in this paper can be used in conjunction with the earlier results published in the CRC Handbook of Carcinogenic Potency and Genotoxicity Databases [Gold LS, Zeiger E, eds. Boca Raton FL:CRC Press, 1997] and with our web site (http://potency.berkeley.edu), which includes a guide to the plot of the database, a complete description of the numerical index of carcinogenic potency (TD50), and a discussion of the sources of data, the rationale for the inclusion of particular experiments and particular target sites, and the conventions adopted in summarizing the literature. Two summary tables permit easy access to the literature of animal cancer tests by target organ and by chemical. For readers using the CPDB extensively, a combined plot on diskette or other format is available from the first author. It includes all results published earlier and in this paper, ordered alphabetically by chemical. A SAS database is also available. PMID:10421768

The Relative Importance of Waterborne and Dietborne Arsenic Exposure on Survival and Growth of Juvenile Rainbow Trout

EPA Science Inventory

Previous work in our laboratory demonstrated toxicity to rainbow trout fed oligochaetes contaminated with arsenic via waterborne exposure. While this demonstrated the potential hazard of dietborne exposure, it did not address the relative and combined potency of waterborne and d...

Update of potency factors for asbestos-related lung cancer and mesothelioma.

PubMed

Berman, D Wayne; Crump, Kenny S

2008-01-01

The most recent update of the U.S. Environmental Protection Agency (EPA) health assessment document for asbestos (Nicholson, 1986, referred to as "the EPA 1986 update") is now 20 years old. That document contains estimates of "potency factors" for asbestos in causing lung cancer (K(L)'s) and mesothelioma (K(M)'s) derived by fitting mathematical models to data from studies of occupational cohorts. The present paper provides a parallel analysis that incorporates data from studies published since the EPA 1986 update. The EPA lung cancer model assumes that the relative risk varies linearly with cumulative exposure lagged 10 years. This implies that the relative risk remains constant after 10 years from last exposure. The EPA mesothelioma model predicts that the mortality rate from mesothelioma increases linearly with the intensity of exposure and, for a given intensity, increases indefinitely after exposure ceases, approximately as the square of time since first exposure lagged 10 years. These assumptions were evaluated using raw data from cohorts where exposures were principally to chrysotile (South Carolina textile workers, Hein et al., 2007; mesothelioma only data from Quebec miners and millers, Liddell et al., 1997) and crocidolite (Wittenoom Gorge, Australia miners and millers, Berry et al., 2004) and using published data from a cohort exposed to amosite (Paterson, NJ, insulation manufacturers, Seidman et al., 1986). Although the linear EPA model generally provided a good description of exposure response for lung cancer, in some cases it did so only by estimating a large background risk relative to the comparison population. Some of these relative risks seem too large to be due to differences in smoking rates and are probably due at least in part to errors in exposure estimates. There was some equivocal evidence that the relative risk decreased with increasing time since last exposure in the Wittenoom cohort, but none either in the South Carolina cohort up to 50 years from last exposure or in the New Jersey cohort up to 35 years from last exposure. The mesothelioma model provided good descriptions of the observed patterns of mortality after exposure ends, with no evidence that risk increases with long times since last exposure at rates that vary from that predicted by the model (i.e., with the square of time). In particular, the model adequately described the mortality rate in Quebec chrysotile miners and millers up through >50 years from last exposure. There was statistically significant evidence in both the Wittenoom and Quebec cohorts that the exposure intensity-response is supralinear(1) rather than linear. The best-fitting models predicted that the mortality rate varies as [intensity](0.47) for Wittenoom and as [intensity](0.19) for Quebec and, in both cases, the exponent was significantly less than 1 (p< .0001). Using the EPA models, K(L)'s and K(M)'s were estimated from the three sets of raw data and also from published data covering a broader range of environments than those originally addressed in the EPA 1986 update. Uncertainty in these estimates was quantified using "uncertainty bounds" that reflect both statistical and nonstatistical uncertainties. Lung cancer potency factors (K(L)'s) were developed from 20 studies from 18 locations, compared to 13 locations covered in the EPA 1986 update. Mesothelioma potency factors (K(M)'s) were developed for 12 locations compared to four locations in the EPA 1986 update. Although the 4 locations used to calculate K(M) in the EPA 1986 update include one location with exposures to amosite and three with exposures to mixed fiber types, the 14 K(M)'s derived in the present analysis also include 6 locations in which exposures were predominantly to chrysotile and 1 where exposures were only to crocidolite. The K(M)'s showed evidence of a trend, with lowest K(M)'s obtained from cohorts exposed predominantly to chrysotile and highest K(M)'s from cohorts exposed only to amphibole asbestos, with K(M)'s from cohorts exposed to mixed fiber types being intermediate between the K(M)'s obtained from chrysotile and amphibole environments. Despite the considerable uncertainty in the K(M) estimates, the K(M) from the Quebec mines and mills was clearly smaller than those from several cohorts exposed to amphibole asbestos or a mixture of amphibole asbestos and chrysotile. For lung cancer, although there is some evidence of larger K(L)'s from amphibole asbestos exposure, there is a good deal of dispersion in the data, and one of the largest K(L)'s is from the South Carolina textile mill where exposures were almost exclusively to chrysotile. This K(L) is clearly inconsistent with the K(L) obtained from the cohort of Quebec chrysotile miners and millers. The K(L)'s and K(M)'s derived herein are defined in terms of concentrations of airborne fibers measured by phase-contrast microscopy (PCM), which only counts all structures longer than 5 microm, thicker than about 0.25 microm, and with an aspect ratio > or =3:1. Moreover, PCM does not distinguish between asbestos and nonasbestos particles. One possible reason for the discrepancies between the K(L)'s and K(M)'s from different studies is that the category of structures included in PCM counts does not correspond closely to biological activity. In the accompanying article (Berman and Crump, 2008) the K(L)'s and K(M)'s and related uncertainty bounds obtained in this article are paired with fiber size distributions from the literature obtained using transmission electron microscopy (TEM). The resulting database is used to define K(L)'s and K(M)'s that depend on both the size (e.g., length and width) and mineralogical type (e.g., chrysotile or crocidolite) of an asbestos structure. An analysis is conducted to determine how well different K(L) and K(M) definitions are able to reconcile the discrepancies observed herein among values obtained from different environments.

Straight-chain alcohols exhibit a cutoff in potency for the inhibition of recombinant glutamate receptor subunits

PubMed Central

Akinshola, B Emmanuel

2001-01-01

The effects of n-alcohols (methanol to 1-decanol) on kainate-activated AMPA receptor subunit GluR1 and GluR3 ion currents were studied in Xenopus oocytes using the two-electrode voltage-clamp recording technique. For short-chain alcohols from methanol to 1-hexanol, potency for inhibition of GluR1 and GluR3 receptor-mediated current increased in proportion to the chain length or hydrophobicity of the alcohol. The IC50 values of these alcohols for GluR1 were: methanol, 702 mM; ethanol, 170 mM; 1-propanol, 69 mM; 1-butanol, 20 mM; 1-pentanol, 17 mM; and 1-hexanol, 10 mM. For GluR3, IC50 values were: methanol, 712 mM; ethanol, 238 mM; 1-propanol, 50 mM; 1-butanol, 32 mM; 1-pentanol, 13 mM; and 1-hexanol, 7 mM. For long-chain alcohols, 1-heptanol was less potent than 1-hexanol (estimated IC50: 19 mM for GluR1 and 18 mM for GluR3), 1-octanol had little effect only on GluR3, and 1-nonanol and 1-decanol did not significantly inhibit both GluR1 and GluR3 responses. The observations indicate that straight-chain n-alcohols exhibit a cutoff in their potency for inhibition of the function of non-NMDA glutamate receptor subunits, GluR1 and GluR3. The cutoff in potency of n-alcohols for inhibition of non-NMDA glutamate receptor function is consistent with the interpretation that alcohols affect the function of these receptor-channels by interacting with an alcohol binding site of specific dimensions on the receptor protein. PMID:11429388

The pilosebaceous unit—a phthalate-induced pathway to skin sensitization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simonsson, Carl, E-mail: carl.simonsson@chem.gu.se; Stenfeldt, Anna-Lena; Karlberg, Ann-Therese

2012-10-01

Allergic contact dermatitis (ACD) is caused by low-molecular weight compounds called haptens. It has been shown that the potency of haptens can depend on the formulation in which they are applied on the skin. Specifically the sensitization potency of isothiocyanates, a group of haptens which can be released from e.g. adhesive tapes and neoprene materials, increases with the presence of phthalates; however, the underlying mechanisms are not clear. A better understanding of the mechanisms governing the potency of haptens is important, e.g. to improve the risk assessment and the formulation of chemicals in consumer products. In this study we havemore » explored phthalate-induced effects on the sensitization potency, skin distribution, and reactivity of fluorescent model isothiocyanate haptens using non-invasive two-photon microscopy to provide new insights regarding vehicle effects in ACD. The data presented in this paper indicate that the sensitization potency of isothiocyanates increases when applied in combination with dibutylphthalate due to a specific uptake via the pilosebaceous units. The results highlight the importance of shunt pathways when evaluating the bioavailability of skin sensitizers. The findings also indicate that vehicle-dependent hapten reactivity towards stratum corneum proteins regulates the bioavailability, and thus the potency, of skin sensitizers. -- Highlights: ► Vehicle effects on sensitization potency were investigated in the LLNA. ► In vivo cutaneous absorption of contact sensitizers was visualized using TPM. ► Sensitizing potency of isothiocyanates depends on the presence of a phthalate. ► Phthalate induced cutaneous absorption via the pilosebaceous units. ► Vehicle-dependent reactivity regulates sensitization potency.« less

Proportion of patients in south London with first-episode psychosis attributable to use of high potency cannabis: a case-control study.

PubMed

Di Forti, Marta; Marconi, Arianna; Carra, Elena; Fraietta, Sara; Trotta, Antonella; Bonomo, Matteo; Bianconi, Francesca; Gardner-Sood, Poonam; O'Connor, Jennifer; Russo, Manuela; Stilo, Simona A; Marques, Tiago Reis; Mondelli, Valeria; Dazzan, Paola; Pariante, Carmine; David, Anthony S; Gaughran, Fiona; Atakan, Zerrin; Iyegbe, Conrad; Powell, John; Morgan, Craig; Lynskey, Michael; Murray, Robin M

2015-03-01

The risk of individuals having adverse effects from drug use (eg, alcohol) generally depends on the frequency of use and potency of the drug used. We aimed to investigate how frequent use of skunk-like (high-potency) cannabis in south London affected the association between cannabis and psychotic disorders. We applied adjusted logistic regression models to data from patients aged 18-65 years presenting to South London and Maudsley NHS Foundation Trust with first-episode psychosis and population controls recruited from the same area of south London (UK) to estimate the effect of the frequency of use, and type of cannabis used on the risk of psychotic disorders. We then calculated the proportion of new cases of psychosis attributable to different types of cannabis use in south London. Between May 1, 2005, and May 31, 2011, we obtained data from 410 patients with first-episode psychosis and 370 population controls. The risk of individuals having a psychotic disorder showed a roughly three-times increase in users of skunk-like cannabis compared with those who never used cannabis (adjusted odds ratio [OR] 2·92, 95% CI 1·52-3·45, p=0·001). Use of skunk-like cannabis every day conferred the highest risk of psychotic disorders compared with no use of cannabis (adjusted OR 5·4, 95% CI 2·81-11·31, p=0·002). The population attributable fraction of first-episode psychosis for skunk use for our geographical area was 24% (95% CI 17-31), possibly because of the high prevalence of use of high-potency cannabis (218 [53%] of 410 patients) in our study. The ready availability of high potency cannabis in south London might have resulted in a greater proportion of first onset psychosis cases being attributed to cannabis use than in previous studies. UK National Institute of Health Research (NIHR) Specialist Biomedical Research Centre for Mental Health, SLaM and the Institute of Psychiatry at King's College London, Psychiatry Research Trust, Maudsley Charity Research Fund, and th European Community's Seventh Framework Program grant (agreement No. HEALTH-F2-2009-241909 [Project EU-GEI]). Copyright © 2015 Di Forti et al. Open Access article distributed under the terms of CC BY. Published by Elsevier Ltd.. All rights reserved.

Glossary of ALS-Related Medical and Scientific Terms

MedlinePlus

... and the amount of that substance. 2. The biological or pharmacological potency of a drug. ataxia Loss ... chemical or physical properties. biochemistry The chemistry of biology; the application of the tools and concepts of ...

International standards for monoclonal antibodies to support pre- and post-marketing product consistency: Evaluation of a candidate international standard for the bioactivities of rituximab.

PubMed

Prior, Sandra; Hufton, Simon E; Fox, Bernard; Dougall, Thomas; Rigsby, Peter; Bristow, Adrian

2018-01-01

The intrinsic complexity and heterogeneity of therapeutic monoclonal antibodies is built into the biosimilarity paradigm where critical quality attributes are controlled in exhaustive comparability studies with the reference medicinal product. The long-term success of biosimilars will depend on reassuring healthcare professionals and patients of consistent product quality, safety and efficacy. With this aim, the World Health Organization has endorsed the need for public bioactivity standards for therapeutic monoclonal antibodies in support of current controls. We have developed a candidate international potency standard for rituximab that was evaluated in a multi-center collaborative study using participants' own qualified Fc-effector function and cell-based binding bioassays. Dose-response curve model parameters were shown to reflect similar behavior amongst rituximab preparations, albeit with some differences in potency. In the absence of a common reference standard, potency estimates were in poor agreement amongst laboratories, but the use of the candidate preparation significantly reduced this variability. Our results suggest that the candidate rituximab standard can support bioassay performance and improve data harmonization, which when implemented will promote consistency of rituximab products over their life-cycles. This data provides the first scientific evidence that a classical standardization exercise allowing traceability of bioassay data to an international standard is also applicable to rituximab. However, we submit that this new type of international standard needs to be used appropriately and its role not to be mistaken with that of the reference medicinal product.

Potency of marbofloxacin for pig pneumonia pathogens Actinobacillus pleuropneumoniae and Pasteurella multocida: Comparison of growth media.

PubMed

Dorey, L; Hobson, S; Lees, P

2017-04-01

Pharmacodynamic properties of marbofloxacin were established for six isolates each of the pig respiratory tract pathogens, Actinobacillus pleuropneumoniae and Pasteurella multocida. Three in vitro indices of potency were determined; Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Mutant Prevention Concentration (MPC). For MIC determination Clinical Laboratory Standards Institute guidelines were modified in three respects: (1) comparison was made between two growth media, an artificial broth and pig serum; (2) a high inoculum count was used to simulate heavy clinical bacteriological loads; and (3) five overlapping sets of two-fold dilutions were used to improve accuracy of determinations. Similar methods were used for MBC and MPC estimations. MIC and MPC serum:broth ratios for A. pleuropneumoniae were 0.79:1 and 0.99:1, respectively, and corresponding values for P. multocida were 1.12:1 and 1.32:1. Serum protein binding of marbofloxacin was 49%, so that fraction unbound (fu) serum MIC values were significantly lower than those predicted by correction for protein binding; fu serum:broth MIC ratios were 0.40:1 (A. pleuropneumoniae) and 0.50:1 (P. multocida). For broth, MPC:MIC ratios were 13.7:1 (A. pleuropneumoniae) and 14.2:1 (P. multocida). Corresponding ratios for serum were similar, 17.2:1 and 18.8:1, respectively. It is suggested that, for dose prediction purposes, serum data might be preferable to potency indices measured in broths. Copyright © 2016 Elsevier Ltd. All rights reserved.

Opioid analgesics: does potency matter?

PubMed

Passik, Steven D; Webster, Lynn

2014-01-01

Prescription opioid analgesics with a wide range of potencies are currently used for the treatment of chronic pain. Yet understanding the clinical relevance and therapeutic consequences of opioid potency remains ill defined. Both patients and clinicians alike have misperceptions about opioid potency, expecting that less-potent opioids will be less effective or fearing that more-potent opioids are more dangerous or more likely to be abused. In this review, common myths about the potency of opioid analgesics will be discussed. Clinicians should understand that pharmacologic potency per se does not necessarily imply more effective analgesia or higher abuse liability. Published dose conversion tables may not accurately calculate the dose for effective and safe rotation from one opioid to another in patients receiving long-term opioid therapy because they are based on limited data that may not apply to chronic pain. Differences in pharmacologic potency are largely accounted for by the actual doses prescribed, according to individualized patient need. Factors for achieving effective analgesia and reducing the risks involved with opioid use include careful medication selection based on patient characteristics, appropriate dosing titration and opioid rotation practices, knowledge of product formulation characteristics (eg, extended release, immediate release, and tamper-resistant features), and an awareness of differences in opioid pharmacokinetics and metabolism. Clinicians should remain vigilant in monitoring patients on any opioid medication, regardless of classification along the opioid potency continuum.

Using a mass balance to determine the potency loss during the production of a pharmaceutical blend.

PubMed

Mackaplow, Michael B

2010-09-01

The manufacture of a blend containing the active pharmaceutical ingredient (API) and inert excipients is a precursor for the production of most pharmaceutical capsules and tablets. However, if there is a net water gain or preferential loss of API during production, the potency of the final drug product may be less than the target value. We use a mass balance to predict the mean potency loss during the production of a blend via wet granulation and fluidized bed drying. The result is an explicit analytical equation for the change in blend potency a function of net water gain, solids losses (both regular and high-potency), and the fraction of excipients added extragranularly. This model predicts that each 1% gain in moisture content (as determined by a loss on drying test) will decrease the API concentration of the final blend at least 1% LC. The effect of pre-blend solid losses increases with their degree of superpotency. This work supports Quality by Design by providing a rational method to set the process design space to minimize blend potency losses. When an overage is necessary, the model can help justify it by providing a quantitative, first-principles understanding of the sources of potency loss. The analysis is applicable to other manufacturing processes where the primary sources of potency loss are net water gain and/or mass losses.

A new ELISA for determination of potency in snake antivenoms.

PubMed

Rial, A; Morais, V; Rossi, S; Massaldi, H

2006-09-15

A competitive ELISA for potency determination of bothropic equine antivenom was developed and compared to the conventional in vivo ED(50) assay, with the aim of partially substituting the in vivo assay in the monitoring of antivenom immunoglobulin levels. On this purpose, blood samples were taken at different times during and after the immunization protocol of the lot of horses used for production of snake antivenom at the Instituto de Higiene, Uruguay. Both the competitive ELISA and the ED(50) assay were performed on those samples. In addition, a group of five commercial pepsin-digested antivenoms were tested by both methods. A significant (P<0.001) correlation (Pearson's r=0.957) was found between the ELISA titres and the corresponding ED(50) values, indicating that the in vitro test can estimate the neutralizing antibody capacity of the sera as well as the in vivo assay. By means of this new ELISA, it was found that the immunized animals maintained good venom antibody titres, in the order of 20-50% of the maximum achieved, even 10 month after the end of the immunization schedule. The main advantage of our ELISA design is its ability to correctly estimate the neutralization capacity of crude hyperimmune plasma and antivenom sera independently of their antibody composition in terms of whole IgG or F(ab')(2) fragment.

21 CFR 610.10 - Potency.

Code of Federal Regulations, 2010 CFR

2010-04-01

... in vitro or in vivo tests, or both, which have been specifically designed for each product so as to indicate its potency in a manner adequate to satisfy the interpretation of potency given by the definition in § 600.3(s) of this chapter. ...

21 CFR 610.10 - Potency.

Code of Federal Regulations, 2011 CFR

2011-04-01

... in vitro or in vivo tests, or both, which have been specifically designed for each product so as to indicate its potency in a manner adequate to satisfy the interpretation of potency given by the definition in § 600.3(s) of this chapter. ...

Exposure reconstruction for the TCDD-exposed NIOSH cohort using a concentration- and age-dependent model of elimination.

PubMed

Aylward, Lesa L; Brunet, Robert C; Starr, Thomas B; Carrier, Gaétan; Delzell, Elizabeth; Cheng, Hong; Beall, Colleen

2005-08-01

Recent studies demonstrating a concentration dependence of elimination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suggest that previous estimates of exposure for occupationally exposed cohorts may have underestimated actual exposure, resulting in a potential overestimate of the carcinogenic potency of TCDD in humans based on the mortality data for these cohorts. Using a database on U.S. chemical manufacturing workers potentially exposed to TCDD compiled by the National Institute for Occupational Safety and Health (NIOSH), we evaluated the impact of using a concentration- and age-dependent elimination model (CADM) (Aylward et al., 2005) on estimates of serum lipid area under the curve (AUC) for the NIOSH cohort. These data were used previously by Steenland et al. (2001) in combination with a first-order elimination model with an 8.7-year half-life to estimate cumulative serum lipid concentration (equivalent to AUC) for these workers for use in cancer dose-response assessment. Serum lipid TCDD measurements taken in 1988 for a subset of the cohort were combined with the NIOSH job exposure matrix and work histories to estimate dose rates per unit of exposure score. We evaluated the effect of choices in regression model (regression on untransformed vs. ln-transformed data and inclusion of a nonzero regression intercept) as well as the impact of choices of elimination models and parameters on estimated AUCs for the cohort. Central estimates for dose rate parameters derived from the serum-sampled subcohort were applied with the elimination models to time-specific exposure scores for the entire cohort to generate AUC estimates for all cohort members. Use of the CADM resulted in improved model fits to the serum sampling data compared to the first-order models. Dose rates varied by a factor of 50 among different combinations of elimination model, parameter sets, and regression models. Use of a CADM results in increases of up to five-fold in AUC estimates for the more highly exposed members of the cohort compared to estimates obtained using the first-order model with 8.7-year half-life. This degree of variation in the AUC estimates for this cohort would affect substantially the cancer potency estimates derived from the mortality data from this cohort. Such variability and uncertainty in the reconstructed serum lipid AUC estimates for this cohort, depending on elimination model, parameter set, and regression model, have not been described previously and are critical components in evaluating the dose-response data from the occupationally exposed populations.

Emamectin is a non-selective allosteric activator of nicotinic acetylcholine receptors and GABAA/C receptors

PubMed Central

Xu, Xiaojun; Sepich, Caraline; Lukas, Ronald J; Zhu, Guonian; Chang, Yongchang

2016-01-01

Avermectins are a group of compounds isolated from a soil-dwelling bacterium. They have been widely used as parasiticides and insecticides, acting by relatively irreversible activation of invertebrate chloride channels. Emamectin is a soluble derivative of an avermectin. It is an insecticide, which persistently activates glutamate-gated chloride channels. However, its effects on mammalian ligand-gated ion channels are unknown. To this end, we tested the effect of emamectin on two cation selective nicotinic receptors and two GABA-gated chloride channels expressed in Xenopus oocytes using two-electrode voltage clamp. Our results demonstrate that emamectin could directly activate α7 nAChR, α4β2 nAChR, α1β2γ2 GABAA receptor and ρ1 GABAC receptor concentration dependently, with similar potencies for each channel. However, the potencies for it to activate these channels were at least two orders of magnitude lower than its potency of activating invertebrate glutamate-gated chloride channel. In contrast, ivermectin only activated the α1β2γ2 GABAA receptor. PMID:27049309

Multidrug Efflux Transporters Limit Accumulation of Inorganic, but Not Organic, Mercury in Sea Urchin Embryos

PubMed Central

Bošnjak, Ivana; Uhlinger, Kevin R.; Heim, Wesley; Smital, Tvrtko; Franekić-Čolić, Jasna; Coale, Kenneth; Epel, David; Hamdoun, Amro

2011-01-01

Mercuric compounds are persistent global pollutants that accumulate in marine organisms and in humans who consume them. While the chemical cycles and speciation of mercury in the oceans are relatively well described, the cellular mechanisms that govern which forms of mercury accumulate in cells and why they persist are less understood. In this study we examined the role of multidrug efflux transport in the differential accumulation of inorganic (HgCl2) and organic (CH3HgCl) mercury in sea urchin (Strongylocentrotus purpuratus) embryos. We found that inhibition of MRP/ABCC-type transporters increases intracellular accumulation of inorganic mercury but had no effect on accumulation of organic mercury. Similarly, pharmacological inhibition of metal conjugating enzymes by ligands GST/GSH significantly increases this antimitotic potency of inorganic mercury, but had no effect on the potency of organic mercury. Our results point to MRP-mediated elimination of inorganic mercury conjugates as a cellular basis for differences in the accumulation and potency of the two major forms of mercury found in marine environments. PMID:19924972

Testing of veterinary clostridial vaccines: from mouse to microtitre plate.

PubMed

Redhead, K; Wood, K; Jackson, K

2012-01-01

Vaccines to protect against clostridial diseases are among the most common veterinary biologicals. Each batch of these materials is subjected to a variety of toxicity and antigenicity tests. The potency of the final vaccine is then assessed by Toxin Neutralisation Test (TNT). All of these tests use mice and have lethal endpoints. Development of alternatives for potency testing was based on ELISAs able to measure antibody levels to the specific toxins relative to a standard serum with a defined unitage. These alternative assays were shown to correlate with the relevant TNTs and have been accepted by European Regulatory Authorities as batch release potency tests. Recently we have developed in vitro cell line alternatives for the toxicity and antigenicity tests for Cl. septicum using the VERO cell line. With this cell line it has been possible to develop in vitro assays which, when compared with the in vivo tests, gave correlations of 87% to 100%. Having shown proof of principle, similar cell line assays have been developed for Cl. novyi and Cl. perfringens types C and D.

Characterizing Class-Specific Exposure-Viral Load Suppression Response of HIV Antiretrovirals Using A Model-Based Meta-Analysis.

PubMed

Xu, Y; Li, Y F; Zhang, D; Dockendorf, M; Tetteh, E; Rizk, M L; Grobler, J A; Lai, M-T; Gobburu, J; Ankrom, W

2016-08-01

We applied model-based meta-analysis of viral suppression as a function of drug exposure and in vitro potency for short-term monotherapy in human immunodeficiency virus type 1 (HIV-1)-infected treatment-naïve patients to set pharmacokinetic targets for development of nonnucleoside reverse transcriptase inhibitors (NNRTIs) and integrase strand transfer inhibitors (InSTIs). We developed class-specific models relating viral load kinetics from monotherapy studies to potency normalized steady-state trough plasma concentrations. These models were integrated with a literature assessment of doses which demonstrated to have long-term efficacy in combination therapy, in order to set steady-state trough concentration targets of 6.17- and 2.15-fold above potency for NNRTIs and InSTIs, respectively. Both the models developed and the pharmacokinetic targets derived can be used to guide compound selection during preclinical development and to predict the dose-response of new antiretrovirals to inform early clinical trial design. © 2016 The Authors. Clinical and Translational Science published by Wiley Periodicals, Inc. on behalf of American Society for Clinical Pharmacology and Therapeutics.

Emamectin is a non-selective allosteric activator of nicotinic acetylcholine receptors and GABAA/C receptors.

PubMed

Xu, Xiaojun; Sepich, Caraline; Lukas, Ronald J; Zhu, Guonian; Chang, Yongchang

2016-05-13

Avermectins are a group of compounds isolated from a soil-dwelling bacterium. They have been widely used as parasiticides and insecticides, acting by relatively irreversible activation of invertebrate chloride channels. Emamectin is a soluble derivative of an avermectin. It is an insecticide, which persistently activates glutamate-gated chloride channels. However, its effects on mammalian ligand-gated ion channels are unknown. To this end, we tested the effect of emamectin on two cation selective nicotinic receptors and two GABA-gated chloride channels expressed in Xenopus oocytes using two-electrode voltage clamp. Our results demonstrate that emamectin could directly activate α7 nAChR, α4β2 nAChR, α1β2γ2 GABAA receptor and ρ1 GABAC receptor concentration dependently, with similar potencies for each channel. However, the potencies for it to activate these channels were at least two orders of magnitude lower than its potency of activating invertebrate glutamate-gated chloride channel. In contrast, ivermectin only activated the α1β2γ2 GABAA receptor. Copyright © 2016 Elsevier Inc. All rights reserved.

Neuromedin N: high affinity interaction with brain neurotensin receptors and rapid inactivation by brain synaptic peptidases.

PubMed

Checler, F; Vincent, J P; Kitabgi, P

1986-07-31

Neuromedin N (NN) is a novel neurotensin (NT)-like hexapeptide recently isolated from porcine spinal cord. NN competitively inhibited the binding of monoiodinated [Trp11]NT to rat brain synaptic membranes with a 19-fold lower potency than NT. In the presence of 1 mM 1,10-phenanthroline or 10 microM bestatin, the potency of NN relative to NT was increased about 5-fold. NN was readily degraded by rat brain synaptic membranes, and NN-(2-6) was the major degradation product. NN-(2-6) did not bind to NT receptors at concentrations up to 1 microM whether or not peptidase inhibitors were present in the binding assay. The rate of degradation by synaptic membranes was nearly 2.5 times higher for NN than for NT. NN degradation by membranes was totally prevented by 1,10-phenanthroline and markedly inhibited by bestatin. The presence of NN in the central nervous system, its high potency to interact with brain NT receptors and its rapid inactivation by brain synaptic peptidases make it a potential neurotransmitter candidate acting at the NT receptor.

Comparative carcinogenic potencies of particulates from diesel engine exhausts, coke oven emissions, roofing tar aerosols and cigarette smoke.

PubMed Central

Albert, R E

1983-01-01

Mammalian cell mutagenesis, transformation and skin tumorigenesis assays show similar results in comparing the potencies of diesel, coke oven, roofing tar and cigarette smoke particulates. These assay results are reasonably consistent with the comparative carcinogenic potencies of coke oven and roofing tar emissions as determined by epidemiological studies. The bacterial mutagenesis assay tends to show disproportionately high potencies, particularly with diesel particulates. Results to date encourage the approach to the assessment for carcinogenic risks from diesel emissions based on the use of epidemiological data on cancer induced by coke oven emissions, roofing tar particulates and cigarette smoke with the comparative potencies of these materials determined by in vivo and in vitro bioassays. PMID:6186481

Bodacious Berry, Potency Wood and the Aging Monster: Gender and Age Relations in Anti-Aging Ads

ERIC Educational Resources Information Center

Calasanti, Toni

2007-01-01

This paper situates age discrimination within a broader system of age relations that intersects with other inequalities, and then uses that framework to analyze internet advertisements for the anti-aging industry. Such ads reinforce age and gender relations by positing old people as worthwhile only to the extent that they look and act like those…

[Comparative studies on purgative potency among three spieces of certified rhubarb].

PubMed

Wang, Jia-kui; Li, Ao; Wang, Hui; Xu, Xiao-yu

2006-12-01

To investigate the difference and causes of purgative activity in three species of certified rhubarb, so as to lay steady foundations of further research on assessing purgative activity impersonally by using measurable indexes. The potencies of three species were comparied with purgative ED, of mice as quantitative index which were calculated, and activities of Na+ K + -ATP ase in mouse colonic epithelial cell membrane were also investigated . The related purgative contents (conjunct and free rhein, chrysophanol, chrysophanic acid, sennoside A) were detected by HPLC and contents (total anthraquinones, anthraglucosennin; conjunct and free anthraquinones) were detected by UV. There were different purgative activities among three spieces of certified rhubarb. Each purgative ED, of mice was Rheum tanguticum ( ED50 = 0. 37 g x kg (-1)) , R. officinale ( ED50 = 0. 99 g x kg(-1) ) and R. palrnatum from Gansu (ED50 = 1. 83 g x kg(-1)) , the ratio of potency of those was 4. 94: 1. 85: 1. In the meanwhile, the difference of the inhibitory effect on Na+ -K + -ATP ase in mouse colonic epithelial cell membrane and relative purgative components also existed in the three species of certified rhubarb. It disclosed that there was notable diference of purgative activity and components among three spieces of certified Rhubarb, which probably resulted in the ultimate diference in clinical prescription and the production of Chinese patent medicines.

Potency Determination of Antidandruff Shampoos in Nystatin International Unit Equivalents

PubMed Central

Anusha Hewage, D. B. G.; Pathirana, W.; Pinnawela, Amara

2008-01-01

A convenient standard microbiological potency determination test for the antidandruff shampoos was developed by adopting the pharmacopoeial microbiological assay procedure of the drug nystatin. A standard curve was drawn consisting of the inhibition zone diameters vs. logarithm of nystatin concentrations in international units using the fungus Saccharomyces cerevisiae (yeast) strain National Collection of Type Culture (NCTC) 1071606 as the test organism. From the standard curve the yeast inhibitory potencies of the shampoos in nystatin international unit equivalents were determined from the respective inhibition zones of the test samples of the shampoos. Under test conditions four shampoo samples showed remarkable fungal inhibitory potencies of 10227, 10731, 12396 and 18211 nystatin international unit equivalents/ml while two shampoo samples had extremely feeble inhibitory potencies 4.07 and 4.37 nystatin international unit equivalents/ml although the latter two products claimed antifungal activity. The potency determination method could be applied to any antidandruff shampoo with any one or a combination of active ingredients. PMID:21394271

Measuring the potency labelling of onabotulinumtoxinA (Botox(®)) and incobotulinumtoxinA (Xeomin (®)) in an LD50 assay.

PubMed

Dressler, Dirk; Mander, Gerd; Fink, Klaus

2012-01-01

The biological potency of botulinum toxin (BT) drugs is determined by a standardised LD50 assay. However, the potency labelling varies vary amongst different BT drugs. One reason for this may be differences in the LD50 assays applied. When five unexpired batches of onabotulinumtoxinA (Botox(®)) and incobotulinumtoxinA (Xeomin(®)) are compared in the Xeomin(®) batch release assay, the potency variability of both BT drugs fell within the range allowed by the European Pharmacopoiea. Statistical analyses failed to detect differences in the potency labelling of both products. Although the existence of a conversion ratio has been questioned recently, our experimental data are in line with previous clinical experience showing that Botox(®) and Xeomin(®) can be compared using a 1:1 conversion ratio. Identical potency labelling allows easy exchange of both BT drugs in a therapeutic setting, and direct comparison of efficacy, adverse effects and costs.

Measurement of Elongated Particle Dissolution Rates and Consequent Size/Shape Distribution Alterations in Support of Relative Potency Determinations and Human Dosimetry Model Development

EPA Science Inventory

Clearance of inhaled bio-persistent elongated particles (EPs) from the lungs and their associated translocation to pleural and other extra-pulmonary tissues involves a number of inter-related and coincidental physicochemical and physiological processes. These can result in EP dis...

Genomic biomarkers of phthalate-induced male reproductive developmental toxicity: A targeted rtPCR array approach for defining relative potency

EPA Science Inventory

Male rat fetuses exposed to certain phthalate esters (PEs) during sexual differentiation display reproductive tract malformations due to reductions in testosterone (T) production and the expression of steroidogenesis-and INSL3-related genes. In the current study} we used a 96well...

Evaluation of genomic biomarkers and relative potency of phthalate-induced male reproductive developmental toxicity using a targeted rtPCR array approach**

EPA Science Inventory

Exposure to certain phthalate esters (PEs) during sexual differentiation induces reproductive tract malformations in male rats due to reductions in fetal testicular testosterone (T) production and expression of steroidogenesis-and insl3-related genes. In the current study, we use...

Cutoff in Potency Implicates Alcohol Inhibition of N-Methyl-D-Aspartate Receptors in Alcohol Intoxication

NASA Astrophysics Data System (ADS)

Peoples, Robert W.; Weight, Forrest F.

1995-03-01

As the number of carbon atoms in an aliphatic n-alcohol is increased from one to five, intoxicating potency, lipid solubility, and membrane lipid disordering potency all increase in a similar exponential manner. However, the potency of aliphatic n-alcohols for producing intoxication reaches a maximum at six to eight carbon atoms and then decreases. The molecular basis of this "cutoff" effect is not understood, as it is not correlated with either the lipid solubility or the membrane disordering potency of the alcohols, which continue to increase exponentially. Since it has been suggested that inhibition of N-methyl-D-aspartate (NMDA) receptors by alcohols may play a role in alcohol intoxication, we investigated whether a series of aliphatic n-alcohols would exhibit a cutoff in potency for inhibition of NMDA receptors. We found that although potency for inhibition of NMDA receptors increased exponentially for alcohols with one to five carbon atoms, potency for inhibition of NMDA receptors reached a maximum at six to eight carbon atoms and then abruptly disappeared. This cutoff for alcohol inhibition of NMDA receptors is consistent with an interaction of the alcohols with a hydrophobic pocket on the receptor protein. In addition, the similarity of the cutoffs for alcohol inhibition of NMDA receptors and alcohol intoxication suggests that the cutoff for NMDA receptor inhibition may contribute to the cutoff for alcohol intoxication, which is consistent with an important role of NMDA receptors in alcohol intoxication.

Antagonism of the morphine-induced locomotor activation of mice by fructose: comparison with other opiates and sugars, and sugar effects on brain morphine.

PubMed

Brase, D A; Ward, C R; Bey, P S; Dewey, W L

1991-01-01

The mouse locomotor activation test of opiate action in a 2+2 dose parallel line assay was used in a repeated testing paradigm to determine the test, opiate and hexose specificities of a previously reported antagonism of morphine-induced antinocociception by hyperglycemia. In opiate specificity studies, fructose (5 g/kg, i.p.) significantly reduced the potency ratio for morphine and methadone, but not for levorphanol, meperidine or phenazocine when intragroup comparisons were made. In intergroup comparisons, fructose significantly reduced the potencies of levorphanol and phenazocine, but not methadone or meperidine. In hexose/polyol specificity studies, tagatose and fructose significantly reduced the potency ratio for morphine, whereas glucose, galactose, mannose and the polyols, sorbitol and xylitol, caused no significant decrease in potency. Fructose, tagatose, glucose and mannose (5 g/kg, i.p.) were tested for effects on brain morphine levels 30 min after morphine (60 min after sugar), and all four sugars significantly increased brain morphine relative to saline-pretreated controls. It is concluded that the antagonism of morphine by acute sugar administration shows specificity for certain sugars and occurs despite sugar-induced increases in the distribution of morphine to the brain. Furthermore, the effects of fructose show an opiate specificity similar to that of glucose on antinociception observed previously in our laboratory, except that methadone was also significantly inhibited in the present study, when a repeated-testing experimental design was used.

Comparison of elicitation potential of chloroatranol and atranol--2 allergens in oak moss absolute.

PubMed

Johansen, Jeanne D; Bernard, Guillaume; Giménez-Arnau, Elena; Lepoittevin, Jean-Pierre; Bruze, Magnus; Andersen, Klaus E

2006-04-01

Chloroatranol and atranol are degradation products of chloroatranorin and atranorin, respectively, and have recently been identified as important contact allergens in the natural fragrance extract, oak moss absolute. Oak moss absolute is widely used in perfumery and is the cause of many cases of fragrance allergic contact dermatitis. Chloroatranol elicits reactions at very low levels of exposure. In oak moss absolute, chloroatranol and atranol are present together and both may contribute to the allergenicity and eliciting capacity of the natural extract. In this study, 10 eczema patients with known sensitization to chloroatranol and oak moss absolute were tested simultaneously to a serial dilution of chloroatranol and atranol in ethanol, in equimolar concentrations (0.0034-1072 microM). Dose-response curves were estimated and analysed by logistic regression. The estimated difference in elicitation potency of chloroatranol relative to atranol based on testing with equimolar concentrations was 217% (95% confidence interval 116-409%). Both substances elicited reactions at very low levels of exposure. It is concluded that the differences in elicitation capacity between the 2 substances are counterbalanced by exposure being greater to atranol than to chloroatranol and that both substances contribute to the clinical problems seen in oak moss absolute-sensitized individuals.

9 CFR 114.9 - Outline of Production guidelines.

Code of Federal Regulations, 2010 CFR

2010-01-01

... each satisfactory test. A. Purity. B. Safety. C. Potency. D. Other tests. VI. Post preparatory steps. A... test. A. Purity. B. Safety. C. Potency. D. Moisture, if desiccated. E. Any other tests. VI. Post.... Potency. D. Any other tests. E. Include any additional pertinent information. IV. Post preparatory steps...

9 CFR 114.9 - Outline of Production guidelines.

Code of Federal Regulations, 2012 CFR

2012-01-01

... each satisfactory test. A. Purity. B. Safety. C. Potency. D. Other tests. VI. Post preparatory steps. A... test. A. Purity. B. Safety. C. Potency. D. Moisture, if desiccated. E. Any other tests. VI. Post.... Potency. D. Any other tests. E. Include any additional pertinent information. IV. Post preparatory steps...

9 CFR 114.9 - Outline of Production guidelines.

Code of Federal Regulations, 2013 CFR

2013-01-01

... each satisfactory test. A. Purity. B. Safety. C. Potency. D. Other tests. VI. Post preparatory steps. A... test. A. Purity. B. Safety. C. Potency. D. Moisture, if desiccated. E. Any other tests. VI. Post.... Potency. D. Any other tests. E. Include any additional pertinent information. IV. Post preparatory steps...

9 CFR 114.9 - Outline of Production guidelines.

Code of Federal Regulations, 2011 CFR

2011-01-01

... each satisfactory test. A. Purity. B. Safety. C. Potency. D. Other tests. VI. Post preparatory steps. A... test. A. Purity. B. Safety. C. Potency. D. Moisture, if desiccated. E. Any other tests. VI. Post.... Potency. D. Any other tests. E. Include any additional pertinent information. IV. Post preparatory steps...

9 CFR 114.9 - Outline of Production guidelines.

Code of Federal Regulations, 2014 CFR

2014-01-01

... each satisfactory test. A. Purity. B. Safety. C. Potency. D. Other tests. VI. Post preparatory steps. A... test. A. Purity. B. Safety. C. Potency. D. Moisture, if desiccated. E. Any other tests. VI. Post.... Potency. D. Any other tests. E. Include any additional pertinent information. IV. Post preparatory steps...

76 FR 9028 - Guidance for Industry: Potency Tests for Cellular and Gene Therapy Products; Availability

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-16

...] Guidance for Industry: Potency Tests for Cellular and Gene Therapy Products; Availability AGENCY: Food and... the availability of a document entitled ``Guidance for Industry: Potency Tests for Cellular and Gene Therapy Products'' dated January 2011. The guidance document provides manufacturers of cellular and gene...

21 CFR 660.22 - Potency requirements with reference preparations.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 7 2011-04-01 2010-04-01 true Potency requirements with reference preparations. 660.22 Section 660.22 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN.... Products for which reference Blood Grouping Reagents are available shall have a potency titer value at...

21 CFR 660.22 - Potency requirements with reference preparations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Potency requirements with reference preparations. 660.22 Section 660.22 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN.... Products for which reference Blood Grouping Reagents are available shall have a potency titer value at...

21 CFR 640.56 - Quality control test for potency.

Code of Federal Regulations, 2011 CFR

2011-04-01

..., Center for Biologics Evaluation and Research, Food and Drug Administration. Such testing shall not be... Evaluation and Research, Food and Drug Administration. (d) If the average potency level of antihemophilic... 21 Food and Drugs 7 2011-04-01 2010-04-01 true Quality control test for potency. 640.56 Section...

Antecedents of team potency and team effectiveness: an examination of goal and process clarity and servant leadership.

PubMed

Hu, Jia; Liden, Robert C

2011-07-01

Integrating theories of self-regulation with team and leadership literatures, this study investigated goal and process clarity and servant leadership as 3 antecedents of team potency and subsequent team effectiveness, operationalized as team performance and organizational citizenship behavior. Our sample of 304 employees represented 71 teams in 5 banks. Results showed that team-level goal and process clarity as well as team servant leadership served as 3 antecedents of team potency and subsequent team performance and team organizational citizenship behavior. Furthermore, we found that servant leadership moderated the relationships between both goal and process clarity and team potency, such that the positive relationships between both goal and process clarity and team potency were stronger in the presence of servant leadership.

Effects of simultaneous immunization of Haemophilus influenzae type b conjugate vaccine and diphtheria-tetanus-acellular pertussis vaccine on anti-tetanus potencies in mice, guinea pigs, and rats.

PubMed

Fukuda, Tadashi; Iwaki, Masaaki; Komiya, Takako; Shibayama, Keigo; Takahashi, Motohide; Nakashima, Hideki

2013-01-01

Haemophilus influenzae type b vaccine conjugated with tetanus toxoid (HibT) was licensed for use in childhood immunization in Japan in 2007. As adsorbed diphtheria-tetanus-acellular pertussis (DTaP) combined with HibT vaccine has not been introduced in Japan, DTaP and HibT vaccines are injected at separate sites with a similar immunization schedule. There are various interfering or stimulatory effects between components of combined vaccines contained in DTaP and HibT vaccines. In this study, we investigated the effect of HibT containing combination vaccines on anti-tetanus potencies by using animal models (mouse, guinea pig, and rat). HibT vaccine and HibT components of imported DTaP-HibT vaccine alone showed comparable or higher anti-tetanus potency than DTaP vaccine and DTaP-containing components of combination vaccines. Mixing these components before injection resulted in potencies greater than the sum of individual potencies. Injecting individual components at separate sites in animals resulted in potency roughly equivalent to the sum of the individual potencies. These results provide useful information regarding the use of HibT-containing multivalent vaccines in childhood immunization.

ENVIRONMENTAL COMPARISON METRICS FOR LIFE CYCLE IMPACT ASSESSMENT AND PROCESS DESIGN

EPA Science Inventory

Metrics (potentials, potency factors, equivalency factors or characterization factors) are available to support the environmental comparison of alternatives in application domains like proces design and product life-cycle assessment (LCA). These metrics typically provide relative...

Are styrene oligomers in coastal sediments of an industrial area aryl hydrocarbon-receptor agonists?

PubMed

Hong, Seongjin; Lee, Junghyun; Lee, Changkeun; Yoon, Seo Joon; Jeon, Seungyeon; Kwon, Bong-Oh; Lee, Jong-Hyeon; Giesy, John P; Khim, Jong Seong

2016-06-01

Effect-directed analysis (EDA) was performed to identify the major aryl hydrocarbon receptor (AhR) agonists in sediments collected from a highly industrialized area (Lake Shihwa, Korea). Great AhR-mediated potencies were found in fractions containing aromatic compounds with log Kow values of 5-8, and relatively great concentrations of styrene oligomers (SOs) and polycyclic aromatic hydrocarbons (PAHs) were detected in those fractions. Until now, there was little information on occurrences and toxic relative potencies (RePs) of SOs in coastal environments. In the present study; i) distributions and compositions, ii) AhR binding affinities, and iii) contributions of SOs to total AhR-mediated potencies were determined in coastal sediments. Elevated concentrations of 10 SOs were detected in sediments of inland creeks ranging from 61 to 740 ng g(-1) dry mass (dm), while lesser concentrations were found in inner (mean = 33 ng g(-1) dm) and outer regions (mean = 25 ng g(-1) dm) of the lake. Concentrations of PAHs in sediments were comparable to those of SOs. 2,4-diphenyl-1-butene (SD3) was the predominant SO analogue in sediments. SOs and PAHs were accumulated in sediments near sources, and could not be transported to remote regions due to their hydrophobicity. RePs of 3 SOs could be derived, which were 1000- to 10,000-fold less than that of one representative potent AhR active PAH, benzo[a]pyrene. Although concentrations of SOs in sediments were comparable to those of PAHs, the collective contribution of SOs to total AhR-mediated potencies were rather small (<1%), primarily due to their smaller RePs. Overall, the present study provides information on distributions and AhR binding affinities for SOs as baseline data for degradation products of polystyrene plastic in the coastal environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cholecystokinin receptors on gallbladder muscle and pancreatic acinar cells: a comparative study

DOE Office of Scientific and Technical Information (OSTI.GOV)

von Schrenck, T.; Moran, T.H.; Heinz-Erian, P.

1988-10-01

To compare receptors for cholecystokinin (CCK) in pancreas and gallbladder, we measured binding of 125I-Bolton-Hunter-labeled CCK-8 (125I-BH-CCK-8) to tissue sections from guinea pig gallbladder and pancreas under identical conditions. In both tissues, binding had similar time-, temperature-, and pH dependence, was reversible, saturable and inhibited only by CCK related peptides or CCK receptor antagonists. Autoradiography localized 125I-BH-CCK-8 binding to the smooth muscle layer in the gallbladder. Binding of 125I-BH-CCK-8 to gallbladder sections was inhibited by various agonists with the following potencies (IC50):CCK-8 (0.4 nM) greater than des(SO3)CCK-8 (0.07 microM) greater than gastrin-17-I (1.7 +/- 0.3 microM) and by various receptormore » antagonists with the following potencies: L364,718 (1.5 nM) greater than CR 1409 (0.19 microM) greater than asperlicin = CBZ-CCK-(27-32)-NH2 (1 microM) greater than Bt2cGMP (120 microM). Similar potencies were found for the agonists and antagonists for pancreas sections. Inhibition of binding of 125I-BH-CCK-8 by 11 different analogues of proglumide gave similar potencies for both pancreas and gallbladder. The potencies of agonists in stimulating and antagonists in inhibiting CCK-stimulated contraction or amylase release correlated closely with their abilities to inhibit 125I-BH-CCK-8 binding to gallbladder or pancreas sections or acini, respectively. The present results demonstrate and characterize a method that can be used to compare the CCK receptors in guinea pig gallbladder and pancreas under identical conditions. Moreover, this study demonstrates that gallbladder and pancreatic CCK receptors have similar affinities for the various agonists and antagonists tested and, therefore, provides no evidence that they represent different subtypes of CCK receptors that can be distinguished pharmacologically.« less

Stress Induces AMP-Dependent Loss of Potency Factors Id2 and Cdx2 in Early Embryos and Stem Cells

PubMed Central

Xie, Yufen; Awonuga, Awoniyi; Liu, Jian; Rings, Edmond; Puscheck, Elizabeth Ella

2013-01-01

The AMP-activated protein kinase (AMPK) mediates rapid, stress-induced loss of the inhibitor of differentiation (Id)2 in blastocysts and trophoblast stem cells (TSC), and a lasting differentiation in TSC. However, it is not known if AMPK regulates other potency factors or regulates them before the blastocyst stage. The caudal-related homeodomain protein (Cdx)2 is a regulatory gene for determining TSC, the earliest placental lineage in the preimplantation mouse embryo, but is expressed in the oocyte and in early cleavage stage embryos before TSC arise. We assayed the expression of putative potency-maintaining phosphorylated Cdx2 ser60 in the oocyte, two-cell stage embryo, blastocyst, and in TSC. We studied the loss of Cdx2 phospho ser60 expression induced by hyperosmolar stress and its underlying mechanisms. Hyperosmolar stress caused rapid loss of nuclear Cdx2 phospho ser60 and Id2 in the two-cell stage embryo by 0.5 h. Stress-induced Cdx2 phospho ser60 and Id2 loss is reversed by the AMPK inhibitor compound C and is induced by the AMPK agonist 5-amino-1-β-d-ribofuranosyl-imidazole-4-carboxamide in the absence of stress. In the two-cell stage embryo and TSC hyperosmolar, stress caused AMPK-mediated loss of Cdx2 phospho ser60 as detected by immunofluorescence and immunoblot. We propose that AMPK may be the master regulatory enzyme for mediating stress-induced loss of potency as AMPK is also required for stress-induced loss of Id2 in blastocysts and TSC. Since AMPK mediates potency loss in embryos and stem cells it will be important to measure, test mechanisms for, and manage the AMPK function to optimize the stem cell and embryo quality in vitro and in vivo. PMID:23316940

Investigating the prevalence, predictors, and prognosis of suboptimal statin use early after a non-ST elevation acute coronary syndrome.

PubMed

Turner, Richard M; Yin, Peng; Hanson, Anita; FitzGerald, Richard; Morris, Andrew P; Stables, Rod H; Jorgensen, Andrea L; Pirmohamed, Munir

High-potency statin therapy is recommended in the secondary prevention of cardiovascular disease but discontinuation, dose reduction, statin switching, and/or nonadherence occur in practice. To determine the prevalence and predictors of deviation from high-potency statin use early after a non-ST elevation acute coronary syndrome (NSTE-ACS) and its association with subsequent major adverse cardiovascular events (MACE) and all-cause mortality (ACM). A total of 1005 patients from a UK-based prospective NSTE-ACS cohort study discharged on high-potency statin therapy (atorvastatin 80 mg, rosuvastatin 20 mg, or 40 mg daily) were included. At 1 month, patients were divided into constant high-potency statin users, and suboptimal users incorporating statin discontinuation, dose reduction, switching statin to a lower equivalent potency, and/or statin nonadherence. Follow-up was a median of 16 months. There were 156 suboptimal (∼15.5%) and 849 constant statin users. Factors associated in multivariable analysis with suboptimal statin occurrence included female sex (odds ratio 1.75, 95% confidence interval [CI] 1.14-2.68) and muscular symptoms (odds ratio 4.28, 95% CI 1.30-14.08). Suboptimal statin use was associated with increased adjusted risks of time to MACE (hazard ratio 2.10, 95% CI 1.25-3.53, P = .005) and ACM (hazard ratio 2.46, 95% CI 1.38-4.39, P = .003). Subgroup analysis confirmed that the increased MACE/ACM risks were principally attributable to statin discontinuation or nonadherence. Conversion to suboptimal statin use is common early after NSTE-ACS and is partly related to muscular symptoms. Statin discontinuation or non-adherence carries an adverse prognosis. Interventions that preserve and enhance statin utilization could improve post NSTE-ACS outcomes. Copyright © 2017 National Lipid Association. Published by Elsevier Inc. All rights reserved.

Radiant power determination of low-level laser therapy equipment and characterization of its clinical use procedures.

PubMed

Guirro, Rinaldo Roberto de Jesus; Weis, Luciana Cezimbra

2009-08-01

The main objectives of this study were to characterize low-level laser therapy (LLLT) and the physical therapy clinical procedures for its use. There are few scientific studies that characterize the calibration of LLLT equipment. Forty lasers at 36 physical therapy clinics were selected. The equipment was characterized through data collected from the owner manuals, direct consultation with the manufacturers, and a questionnaire answered by the users. A digital potency analyzer was used to calibrate released mean potency. Qualitative data were presented throughout the descriptive statistics and quantitative data were analyzed by the Wilcoxon/Kruskal-Wallis and Fisher tests (significance, p < 0.05). The laser equipment was either AsGa (70.5%) or HeNe (23.5%), and 60% was analog and acquired over 5 years ago. The majority of the equipment was used 10-15 times per week and the most frequent density level used was 2 to 4 J/cm(2). Protective goggles were available in only 19.4% of the clinics evaluated. The association between the analyzed categories demonstrated that a lower mean potency was correlated both with equipment acquired over 5 years ago and analog technology. The determined mean potency was lower than the one claimed by the manufacturer (p < 0.05). In 30 cases, the analyzed equipment presented a potency between 3 microW and 5.6 mW; in three cases, the potency was >25 mW; and in seven cases, potency was nonexistent. The analyzed equipment was out-dated and periodical maintenance was not conducted, which was reflected in the low irradiated potency.

21 CFR 640.56 - Quality control test for potency.

Code of Federal Regulations, 2010 CFR

2010-04-01

... quality control test for potency may be performed by a clinical laboratory which meets the standards of... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Quality control test for potency. 640.56 Section...) BIOLOGICS ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Cryoprecipitate § 640.56 Quality control...

21 CFR 660.4 - Potency test.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 7 2013-04-01 2013-04-01 false Potency test. 660.4 Section 660.4 Food and Drugs... STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Antibody to Hepatitis B Surface Antigen § 660.4 Potency test. To be satisfactory for release, each filling of Antibody to Hepatitis B Surface Antigen...

21 CFR 660.43 - Potency test.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 7 2013-04-01 2013-04-01 false Potency test. 660.43 Section 660.43 Food and Drugs... STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Hepatitis B Surface Antigen § 660.43 Potency test... antibody in the appropriate sera of the reference panel by all test methods recommended by the manufacturer...

Natural occurrence of genotoxic and carcinogenic alkenylbenzenes in Indonesian jamu and evaluation of consumer risks.

PubMed

Suparmi, Suparmi; Widiastuti, Diana; Wesseling, Sebastiaan; Rietjens, Ivonne M C M

2018-05-01

The consumer risks of jamu, Indonesian traditional herbal medicines, was assessed focussing on the presence of alkenylbenzene containing botanical ingredients. Twenty-three out of 25 samples contained alkenylbenzenes at levels ranging from 3.8 to 440 μg/kg, with methyleugenol being the most frequently encountered alkenylbenzene. The estimated daily intake (EDI) resulting from jamu consumption was estimated to amount to 0.2-171 μg/kg bw/day for individual alkenylbenzenes, to 0.9-203 μg/kg bw/day when adding up all alkenylbenzenes detected, and to 0.9-551 μg/kg bw/day when expressed in methyleugenol equivalents using interim relative potency (REP) factors. The margin of exposure (MOE) values obtained were generally <10,000 indicating a priority for risk management when assuming daily consumption during a lifetime. Using Haber's rule it was estimated that two weeks consumption of these jamu only once would not raise a concern (MOE >10,000). However, when considering use for two weeks every year during a lifetime, 5 samples still raise a concern. It is concluded that the consumption of alkenylbenzene containing jamu can be of concern especially when consumed on a daily basis for longer periods of time on a regular basis. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Free radical scavenging potency of quercetin catecholic colonic metabolites: Thermodynamics of 2H+/2e- processes.

PubMed

Amić, Ana; Lučić, Bono; Stepanić, Višnja; Marković, Zoran; Marković, Svetlana; Dimitrić Marković, Jasmina M; Amić, Dragan

2017-03-01

Reaction energetics of the double (2H + /2e - ), i.e., the first 1H + /1e - (catechol→ phenoxyl radical) and the second 1H + /1e - (phenoxyl radical→ quinone) free radical scavenging mechanisms of quercetin and its six colonic catecholic metabolites (caffeic acid, hydrocaffeic acid, homoprotocatechuic acid, protocatechuic acid, 4-methylcatechol, and catechol) were computationally studied using density functional theory, with the aim to estimate the antiradical potency of these molecules. We found that second hydrogen atom transfer (HAT) and second sequential proton loss electron transfer (SPLET) mechanisms are less energy demanding than the first ones indicating 2H + /2e - processes as inherent to catechol moiety. The Gibbs free energy change for reactions of inactivation of selected free radicals indicate that catecholic colonic metabolites constitute an efficient group of more potent scavengers than quercetin itself, able to deactivate various free radicals, under different biological conditions. They could be responsible for the health benefits associated with regular intake of flavonoid-rich diet. Copyright © 2016 Elsevier Ltd. All rights reserved.

Recombinant to modified factor VIII and factor IX - chromogenic and one-stage assays issues.

PubMed

Kitchen, S; Kershaw, G; Tiefenbacher, S

2016-07-01

The recent development of modified recombinant factor VIII (FVIII) and factor IX (FIX) therapeutic products with extended half-lives will create challenges for the haemostasis laboratory in obtaining recovery estimates of these products in clinical samples using existing assays. The new long-acting therapeutic concentrates contain molecular modifications of Fc fusion, site-specific of polyethylene glycol or albumin fusion. The optimum methods for monitoring each new product will need to be assessed individually and laboratories should select an assay which gives similar results to the assay used to assign potency to the product in question. For some extended half-life FVIII and FIX products some one stage assays are entirely unsuitable for monitoring purposes. For most products and assay reagents studied so far, and reviewed in this manuscript, chromogenic FVIII or FIX assays can be safely used with conventional plasma standards. If one stage assays are used then they should be performed using carefully selected reagents/methods which have been shown to recover activity close to the labelled potency for the specific product being monitored. © 2016 John Wiley & Sons Ltd.

Homeopathy for Depression - DEP-HOM: study protocol for a randomized, partially double-blind, placebo controlled, four armed study

PubMed Central

2011-01-01

Background Homeopathy is often sought by patients with depression. In classical homeopathy, the treatment consists of two main elements: the case history and the prescription of an individually selected homeopathic remedy. Previous data suggest that individualized homeopathic Q-potencies were not inferior to the antidepressant fluoxetine in a sample of patients with moderate to severe depression. However, the question remains whether individualized homeopathic Q-potencies and/or the type of the homeopathic case history have a specific therapeutical effect in acute depression as this has not yet been investigated. The study aims to assess the two components of individualized homeopathic treatment for acute depression, i.e., to investigate the specific effect of individualized Q-potencies versus placebo and to investigate the effect of different approaches to the homeopathic case history. Methods/Design A randomized, partially double-blind, placebo-controlled, four-armed trial using a 2 × 2 factorial design with a six-week study duration per patient will be performed. 228 patients diagnosed with major depression (moderate episode) by a psychiatrist will be included. The primary endpoint is the total score on the 17-item Hamilton Depression Rating Scale after six weeks. Secondary end points are: Hamilton Depression Rating Scale total score after two and four weeks; response and remission rates, Beck Depression inventory total score, quality of life and safety at two, four and six weeks. Statistical analyses will be by intention-to-treat. The main endpoint will be analysed by a two-factorial analysis of covariance. Within this model generalized estimation equations will be used to estimate differences between verum and placebo, and between both types of case history. Discussion For the first time this study evaluates both the specific effect of homeopathic medicines and of a homeopathic case taking in patients with depression. It is an attempt to deal with the challenges of homeopathic research and the results might be useful information in the current discussion about the evidence on homeopathy Trial registration ClinicalTrials.gov: NCT01178255 PMID:21320338

TETRAMETHRIN AND DDT INHIBIT SPONTANEOUS FIRING IN CORTICAL NEURONAL NETWORKS

EPA Science Inventory

The insecticidal and neurotoxic effects of pyrethroids result from prolonged sodium channel inactivation, which causes alterations in neuronal firing and communication. Previously, we determined the relative potencies of 11 type I and type II pyrethroid insecticides using microel...

INDUCTION OF TRISOMICS BY PLATINUM DIAMINODINITRODICHLORIDE

EPA Science Inventory

Trisomics were produced in the pollen mother cells of Pennisetum americanum (L) K. Schum plants resulting from seeds treated with M to the minus 6th power platinum diaminodinitrodichloride. On the basis of the preliminary study the relative potency of cis-Platinum diaminodinitrod...

Solid State Stability of Extemporaneously Prepared Levothyroxine Aliquots and Capsules.

PubMed

Fortner, Jeff; Salton, Jason; Carlson, Christie; Wheeler, Rich; Cote, Brianna; Rao, Deepa

2015-01-01

The purpose of this research was to collect, analyze, and compare stability data for levothyroxine (T4) powder in the anhydrous and pentahydrate form when prepared as an aliquot and in capsules. Two different compounding pharmacies, Central Iowa Compounding and Gateway Medical Pharmacy, used different forms of T4 and aliquot formulations, which were studied to determine the beyond-use date at ±5% or ±10% of labeled strength. T4 was extracted from aliquot and capsule formulations and assessed using reverse-phase high- performance liquid chromatography validated to differentiate between the degraded and original forms of T4. The results indicate that T4 1:100 aliquot formulation prepared with silica gel or Avicel as filler are stable for 120 days at ±10% labeled potency, but at ±5% labeled potency, the silica gel and Avicel aliquot formulations are stable for 45 and 30 days, respectively. The silica gel capsules prepared from fresh aliquot were stable for 120 days at ±10% labeled potency and 90 days at ±5% labeled potency, while the Avicel capsules prepared from fresh aliquot were stable for 180 days at both ±10% and ±5% labeled potency. Avicel capsules prepared from old aliquot (120 days) and fresh aliquot (1 day) were also compared for stability. The old aliquot Avicel capsules were stable for 14 days at ±5% labeled potency and 150 days at ±10% labeled potency, while new aliquot Avicel capsules were stable for 180 days at both ±10% and ±5% labeled potency. Based on our data, there can be significant variation in the beyond-use dates assigned to T4 capsules based on the diluents used for aliquots, the final capsule formulations, and the potency standards applied. These results also indicate that pharmacists must exercise caution when using older aliquots and may have to assign shorter beyond-use dates.

International standards for monoclonal antibodies to support pre- and post-marketing product consistency: Evaluation of a candidate international standard for the bioactivities of rituximab

PubMed Central

Prior, Sandra; Hufton, Simon E.; Dougall, Thomas; Rigsby, Peter; Bristow, Adrian

2018-01-01

ABSTRACT The intrinsic complexity and heterogeneity of therapeutic monoclonal antibodies is built into the biosimilarity paradigm where critical quality attributes are controlled in exhaustive comparability studies with the reference medicinal product. The long-term success of biosimilars will depend on reassuring healthcare professionals and patients of consistent product quality, safety and efficacy. With this aim, the World Health Organization has endorsed the need for public bioactivity standards for therapeutic monoclonal antibodies in support of current controls. We have developed a candidate international potency standard for rituximab that was evaluated in a multi-center collaborative study using participants' own qualified Fc-effector function and cell-based binding bioassays. Dose-response curve model parameters were shown to reflect similar behavior amongst rituximab preparations, albeit with some differences in potency. In the absence of a common reference standard, potency estimates were in poor agreement amongst laboratories, but the use of the candidate preparation significantly reduced this variability. Our results suggest that the candidate rituximab standard can support bioassay performance and improve data harmonization, which when implemented will promote consistency of rituximab products over their life-cycles. This data provides the first scientific evidence that a classical standardization exercise allowing traceability of bioassay data to an international standard is also applicable to rituximab. However, we submit that this new type of international standard needs to be used appropriately and its role not to be mistaken with that of the reference medicinal product. PMID:28985159

The local lymph node assay compared with the human maximization test as an indicator of allergic potency in humans using patch test clinic populations.

PubMed

Zaghi, Danny; Maibach, Howard I

2009-01-01

The human maximization test (HMT) is a method to evaluate potency in humans, while the local lymph node assay (LLNA) is a test method that allows for the measuring of the allergic potency of a substance in a rodent. It has been proposed that an EC3 value (the value obtained by the LLNA test, ie, the concentration of an allergen leading to a 3-fold increase of baseline proliferation rate) would be a reliable indicator for a compound's allergic potency in humans. This paper compares the correlation between the EC3 value of a compound and its allergic occurrence in the general population with the correlation between the HMT of the compound and its allergic occurrence in the general population, to determine the relationship to potency. The correlation values when outliers were removed from the sample were -0.56 and -0.71 for LLNA and HMT, respectively, suggesting that there is a possible 20% error margin in LLNA's ability to predict potency. The data also suggest that other factors (such as exposure) could play up to a 30% role in the determination of allergic occurrence in the general population. The potency assays might be made more clinically relevant for predicting allergic frequencies by including a frequency factor and other factors in its dermatotoxicological interpretation.

Escape from neutralization by the respiratory syncytial virus-specific neutralizing monoclonal antibody palivizumab is driven by changes in on-rate of binding to the fusion protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bates, John T.; Keefer, Christopher J.; Slaughter, James C.

2014-04-15

The role of binding kinetics in determining neutralizing potency for antiviral antibodies is poorly understood. While it is believed that increased steady-state affinity correlates positively with increased virus-neutralizing activity, the relationship between association or dissociation rate and neutralization potency is unclear. We investigated the effect of naturally-occurring antibody resistance mutations in the RSV F protein on the kinetics of binding to palivizumab. Escape from palivizumab-mediated neutralization of RSV occurred with reduced association rate (K{sub on}) for binding to RSV F protein, while alteration of dissociation rate (K{sub off}) did not significantly affect neutralizing activity. Interestingly, linkage of reduced K{sub on}more » with reduced potency mirrored the effect of increased K{sub on} found in a high-affinity enhanced potency palivizumab variant (motavizumab). These data suggest that association rate is the dominant factor driving neutralization potency for antibodies to RSV F protein antigenic site A and determines the potency of antibody somatic variants or efficiency of escape of viral glycoprotein variants. - Highlights: • The relationship of affinity to neutralization for virus antibodies is uncertain. • Palivizumab binds to RSV escape mutant fusion proteins, but with reduced affinity. • Association rate (K{sub on}) correlated well with the potency of neutralization.« less

Improvement of Parameter Estimations in Tumor Growth Inhibition Models on Xenografted Animals: Handling Sacrifice Censoring and Error Caused by Experimental Measurement on Larger Tumor Sizes.

PubMed

Pierrillas, Philippe B; Tod, Michel; Amiel, Magali; Chenel, Marylore; Henin, Emilie

2016-09-01

The purpose of this study was to explore the impact of censoring due to animal sacrifice on parameter estimates and tumor volume calculated from two diameters in larger tumors during tumor growth experiments in preclinical studies. The type of measurement error that can be expected was also investigated. Different scenarios were challenged using the stochastic simulation and estimation process. One thousand datasets were simulated under the design of a typical tumor growth study in xenografted mice, and then, eight approaches were used for parameter estimation with the simulated datasets. The distribution of estimates and simulation-based diagnostics were computed for comparison. The different approaches were robust regarding the choice of residual error and gave equivalent results. However, by not considering missing data induced by sacrificing the animal, parameter estimates were biased and led to false inferences in terms of compound potency; the threshold concentration for tumor eradication when ignoring censoring was 581 ng.ml(-1), but the true value was 240 ng.ml(-1).

Biological and chemical analysis of the toxic potency of pesticides in rainwater.

PubMed

Hamers, T; Smit, M G; Murk, A J; Koeman, J H

2001-11-01

A newly developed method for measuring the integrated esterase inhibiting potency of rainwater samples was applied in practice, and the results are compared to the toxic potency calculated from concentrations of 31 organophosphate (OP) and carbamate pesticides, out of a total of 66 chemically analyzed pesticides. In addition, the general toxic potency of the rainwater samples was evaluated in a microtiter luminescence assay with Vibrio fischeri bacteria. Rainwater samples were collected over four consecutive 14-day periods in both open and wet-only samplers. The esterase inhibiting potency of the open rainwater samples (expressed as ng dichlorvos-equivalents/l) corresponded well with the chemical analyses of the rainwater samples collected by both types of samplers (r = 0.83-0.86). By far, the highest esterase inhibiting potency was found in a sample collected in an area with intense horticultural activities in June, and was attributed to high concentrations of dichlorvos, mevinphos, pirimiphos-methyl and methiocarb. The esterase inhibiting potency of this sample was equivalent to a dichlorvos concentration of 1380 ng/l in the rainwater, which is almost 2000 times higher than the maximum permissible concentration (MPC) of dichlorvos set for surface water in Netherlands. Maximum individual concentrations of dichlorvos and pirimiphos-methyl even exceeded the EC50 for Daphnia, suggesting that pesticides in rainwater pose a risk for aquatic organisms. Not all responses of the luminescence-assay for general toxicity could be explained by the analyzed pesticide concentrations. The bio-assays enable a direct assessment the toxic potency of all individual compounds present in the complex mixture of rainwater pollutants, even if they are unknown or present at concentrations below the detection limit. Therefore, they are valuable tools for prescreening and hazard characterization purposes.

HEALTH CONSEQUENCES OF DIOXIN EXPOSURE

EPA Science Inventory

Abstract TCDD is often called the most toxic man-made chemical because of its potency to cause health effects in a wide variety of vertebrates. Structurally related persistent compounds, known as 'dioxins', have the same plethora of responses. Dioxins have effects in mu...

RELATIVE POTENCIES FOR ACUTE EFFECTS OF PYRETHROIDS ON MOTOR FUNCTION IN RATS.

EPA Science Inventory

A proposed common mode-of-action for pyrethroid insecticides, includes alterations in sodium channel dynamics in nervous system tissues, consequent disturbance of neuronal membrane polarization, abnormal discharge in targeted neurons, and changes in nervous system function. The p...

Relative Mesothelioma Potencies for Unregulated Respirable Elongated Mineral and Synthetic Particles

EPA Science Inventory

For decades uncertainties and contradictions have surrounded the issue of whether exposures to respirable elongated mineral and synthetic particles (REMPs and RESPs) present health risks such as those recognized for exposures to elongated asbestiform mineral particles from the fi...

Specific Stereoisomeric Conformations Determine the Drug Potency of Cladosporin Scaffold against Malarial Parasite.

PubMed

Das, Pronay; Babbar, Palak; Malhotra, Nipun; Sharma, Manmohan; Jachak, Gorakhnath R; Gonnade, Rajesh G; Shanmugam, Dhanasekaran; Harlos, Karl; Yogavel, Manickam; Sharma, Amit; Reddy, D Srinivasa

2018-05-21

The dependence of drug potency on diastereomeric configurations is a key facet. Using a novel general divergent synthetic route for a three-chiral centre anti-malarial natural product cladosporin, we built its complete library of stereoisomers (cladologs) and assessed their inhibitory potential using parasite-, enzyme- and structure-based assays. We show that potency is manifest via tetrahyropyran ring conformations that are housed in the ribose binding pocket of parasite lysyl tRNA synthetase (KRS). Strikingly, drug potency between top and worst enantiomers varied 500-fold, and structures of KRS-cladolog complexes reveal that alterations at C3 and C10 are detrimental to drug potency where changes at C3 are sensed by rotameric flipping of Glutamate332. Given that scores of anti-malarial and anti-infective drugs contain chiral centers, this work provides a new foundation for focusing on inhibitor stereochemistry as a facet of anti-microbial drug development.

Zscan4 restores the developmental potency of embryonic stem cells

PubMed Central

Amano, Tomokazu; Hirata, Tetsuya; Falco, Geppino; Monti, Manuela; Sharova, Lioudmila V.; Amano, Misa; Sheer, Sarah; Hoang, Hien G.; Piao, Yulan; Stagg, Carole A.; Yamamizu, Kohei; Akiyama, Tomohiko; Ko, Minoru S.H.

2013-01-01

The developmental potency of mouse embryonic stem (ES) cells, which is the ability to contribute to a whole embryo is known to deteriorate during long-term cell culture. Previously we have shown that ES cells oscillate between Zscan4- and Zscan4+ states, and the transient activation of Zscan4 is required for the maintenance of telomeres and genome stability of ES cells. Here we show that increasing the frequency of Zscan4 activation in mouse ES cells restores and maintains their developmental potency in long-term cell culture. Injection of a single ES cell with such increased potency into a tetraploid blastocyst gives rise to an entire embryo with a higher success rate. These results not only provide a means to rejuvenate ES cells by manipulating Zscan4 expression, but also indicate the active roles of Zscan4 in the long-term maintenance of ES cell potency. PMID:23739662

A novel human-based receptor antagonist of sustained action reveals body weight control by endogenous GLP-1.

PubMed

Patterson, James T; Ottaway, Nickki; Gelfanov, Vasily M; Smiley, David L; Perez-Tilve, Diego; Pfluger, Paul T; Tschöp, Matthias H; Dimarchi, Richard D

2011-02-18

Ex-4 (9-39)a is a well characterized GLP-1 receptor antagonist that suffers from two notable limitations, its nonhuman amino acid sequence and its relatively short in vivo duration of action. Comparable N-terminal shortening of human GLP-1 lessens agonism but does not provide a high potency antagonist. Through a series of GLP-1/Ex-4 hybrid peptides, the minimal structural changes required to generate a pure GLP-1-based antagonist were identified as Glu16, Val19, and Arg20, yielding an antagonist of approximately 3-fold greater in vitro potency compared with Ex-4 (9-39)a. The structural basis of antagonism appears to result from stabilization of the α helix combined with enhanced electrostatic and hydrophobic interactions with the extracellular domain of the receptor. Site-specific acylation of the human-based antagonist yielded a peptide of increased potency as a GLP-1 receptor antagonist and 10-fold greater selectivity relative to the GIP receptor. The acylated antagonist demonstrated sufficient duration of action to maintain inhibitory activity when administered as a daily subcutaneous injection. The sustained pharmacokinetics and enhanced human sequence combine to form an antagonist optimized for clinical study. Daily administration of this antagonist by subcutaneous injection to diet-induced obese mice for 1 week caused a significant increase in food intake, body weight, and glucose intolerance, demonstrating endogenous GLP-1 as a relevant hormone in mammalian energy balance in the obese state.

A human induced pluripotent stem cell-based in vitro assay predicts developmental toxicity through a retinoic acid receptor-mediated pathway for a series of related retinoid analogues.

PubMed

Palmer, Jessica A; Smith, Alan M; Egnash, Laura A; Colwell, Michael R; Donley, Elizabeth L R; Kirchner, Fred R; Burrier, Robert E

2017-10-01

The relative developmental toxicity potency of a series of retinoid analogues was evaluated using a human induced pluripotent stem (iPS) cell assay that measures changes in the biomarkers ornithine and cystine. Analogue potency was predicted, based on the assay endpoint of the ornithine/cystine (o/c) ratio, to be all-trans-retinoic acid>TTNPB>13-cis-retinoic acid≈9-cis-retinoic acid>acitretin>etretinate>retinol. These rankings correlate with in vivo data and demonstrate successful application of the assay to rank a series of related toxic and non-toxic compounds. The retinoic acid receptor α (RARα)-selective antagonist Ro 41-5253 inhibited the cystine perturbation caused by all-trans-retinoic acid, TTNPB, 13-cis-retinoic acid, 9-cis-retinoic acid, and acitretin. Ornithine was altered independent of RARα in all retinoids except acitretin. These results suggest a role for an RARα-mediated mechanism in retinoid-induced developmental toxicity through altered cystine metabolism. Copyright © 2017 Elsevier Inc. All rights reserved.

The Nucleation Potency of In Situ-Formed Oxides in Liquid Iron

NASA Astrophysics Data System (ADS)

Xu, Mingqin; Wang, Lu; Lu, Wenquan; Zeng, Long; Nadendla, Hari-Babu; Wang, Yun; Li, Jun; Hu, Qiaodan; Xia, Mingxu; Li, Jianguo

2018-03-01

The nucleation potency of iron oxides was verified experimentally through nucleation undercooling of liquid iron using aerodynamic levitation technology for minimized container contaminations. Steady undercooling values were subsequently obtained from multiple melting and freezing thermal cycles, with the average undercooling values of 223 K ± 3 K and 75 K ± 6 K (223 °C ± 3 °C and 75 °C ± 6 °C) for FeO-contained liquid and Fe3O4-contained liquid, respectively. The statistical results showed a negligible difference in the sizes and numbers of particles between FeO and Fe3O4 particles, indicating that the nucleation potency difference is attributed to the nature of nucleants rather than particle size or numbers. Furthermore, high-resolution transmission electron microscopy analysis showed that the potential nucleation interfaces can be assumed as { 1 1 0}_{{δ {{-Fe}}}} //( 0 0\\bar{2})_{FeO} and { 1 1 2}_{{δ {{-Fe}}}} //(\\bar{2} 0 2 )_{{{Fe}3 {O}4 }} , based on the detected exposed crystal planes of the oxide particles. Both the interfaces have relatively large values of lattice misfit, consistent with the experimentally measured undercooling based on Turnbull's lattice matching theory.

Transmembrane domain I contributes to the permeation pathway for serotonin and ions in the serotonin transporter.

PubMed

Barker, E L; Moore, K R; Rakhshan, F; Blakely, R D

1999-06-15

Mutation of a conserved Asp (D98) in the rat serotonin (5HT) transporter (rSERT) to Glu (D98E) led to decreased 5HT transport capacity, diminished coupling to extracellular Na+ and Cl-, and a selective loss of antagonist potencies (cocaine, imipramine, and citalopram but not paroxetine or mazindol) with no change in 5HT Km value. D98E, which extends the acidic side chain by one carbon, affected the rank-order potency of substrate analogs for inhibition of 5HT transport, selectively increasing the potency of two analogs with shorter alkylamine side chains, gramine, and dihydroxybenzylamine. D98E also increased the efficacy of gramine relative to 5HT for inducing substrate-activated currents in Xenopus laevis oocytes, but these currents were noticeably dependent on extracellular medium acidification. I-V profiles for substrate-independent and -dependent currents indicated that the mutation selectively impacts ion permeation coupled to 5HT occupancy. The ability of the D98E mutant to modulate selective aspects of substrate recognition, to perturb ion dependence as well as modify substrate-induced currents, suggests that transmembrane domain I plays a critical role in defining the permeation pathway of biogenic amine transporters.

Enterocin A Mutants Identified by Saturation Mutagenesis Enhance Potency Towards Vancomycin-Resistant Enterococci

PubMed Central

McClintock, Maria K.; Kaznessis, Yiannis N.; Hackel, Benjamin J.

2016-01-01

Vancomycin-resistant Enterococci infections are a significant clinical problem. One proposed solution is to use probiotics, such as lactic acid bacteria, to produce antimicrobial peptides at the site of infection. Enterocin A, a class 2a bacteriocin, exhibits inhibitory activity against E. faecium and E. faecalis, which account for 86% of vancomycin-resistant Enterococci infections. In this study, we aimed to engineer enterocin A mutants with enhanced potency within a lactic acid bacterial production system. Peptide mutants resulting from saturation mutagenesis at sites A24 and T27 were efficiently screened in a 96-well plate assay for inhibition of pathogen growth. Several mutants exhibit increased potency relative to wild-type enterocin A in both liquid- and solid-medium growth assays. In particular, A24P and T27G exhibit enhanced inhibition of multiple strains of E. faecium and E. faecalis, including clinically isolated vancomycin-resistant strains. A24P and T27G enhance killing of E. faecium 8 by 13±3- and 18±4-fold, respectively. The engineered enterocin A/lactic acid bacteria systems offer significant potential to combat antibiotic-resistant infections. PMID:26191783

Enterocin A mutants identified by saturation mutagenesis enhance potency towards vancomycin-resistant Enterococci.

PubMed

McClintock, Maria K; Kaznessis, Yiannis N; Hackel, Benjamin J

2016-02-01

Vancomycin-resistant Enterococci infections are a significant clinical problem. One proposed solution is to use probiotics, such as lactic acid bacteria, to produce antimicrobial peptides at the site of infection. Enterocin A, a class 2a bacteriocin, exhibits inhibitory activity against E. faecium and E. faecalis, which account for 86% of vancomycin-resistant Enterococci infections. In this study, we aimed to engineer enterocin A mutants with enhanced potency within a lactic acid bacterial production system. Peptide mutants resulting from saturation mutagenesis at sites A24 and T27 were efficiently screened in a 96-well plate assay for inhibition of pathogen growth. Several mutants exhibit increased potency relative to wild-type enterocin A in both liquid- and solid-medium growth assays. In particular, A24P and T27G exhibit enhanced inhibition of multiple strains of E. faecium and E. faecalis, including clinically isolated vancomycin-resistant strains. A24P and T27G enhance killing of E. faecium 8 by 13 ± 3- and 18 ± 4-fold, respectively. The engineered enterocin A/lactic acid bacteria systems offer significant potential to combat antibiotic-resistant infections. © 2015 Wiley Periodicals, Inc.

Monoclonal Antibody Combinations that Present Synergistic Neutralizing Activity: A Platform for Next-Generation Anti-Toxin Drugs

PubMed Central

Diamant, Eran; Torgeman, Amram; Ozeri, Eyal; Zichel, Ran

2015-01-01

Monoclonal antibodies (MAbs) are among the fastest-growing therapeutics and are being developed for a broad range of indications, including the neutralization of toxins, bacteria and viruses. Nevertheless, MAbs potency is still relatively low when compared to conventional polyclonal Ab preparations. Moreover, the efficacy of an individual neutralizing MAb may significantly be hampered by the potential absence or modification of its target epitope in a mutant or subtype of the infectious agent. These limitations of individual neutralizing MAbs can be overcome by using oligoclonal combinations of several MAbs with different specificities to the target antigen. Studies conducted in our lab and by others show that such combined MAb preparation may present substantial synergy in its potency over the calculated additive potency of its individual MAb components. Moreover, oligoclonal preparation is expected to be better suited to compensating for reduced efficacy due to epitope variation. In this review, the synergistic neutralization properties of combined oligoclonal Ab preparations are described. The effect of Ab affinity, autologous Fc fraction, and targeting a critical number of epitopes, as well as the unexpected contribution of non-neutralizing clones to the synergistic neutralizing effect are presented and discussed. PMID:26035486

Steric parameters, molecular modeling and hydropathic interaction analysis of the pharmacology of para-substituted methcathinone analogues

PubMed Central

Sakloth, F; Kolanos, R; Mosier, P D; Bonano, J S; Banks, M L; Partilla, J S; Baumann, M H; Negus, S S; Glennon, R A

2015-01-01

Background and Purpose There is growing concern over the abuse of certain psychostimulant methcathinone (MCAT) analogues. This study extends an initial quantitative structure–activity relationship (QSAR) investigation that demonstrated important steric considerations of seven 4- (or para-)substituted analogues of MCAT. Specifically, the steric character (Taft's steric ES) of the 4-position substituent affected in vitro potency to induce monoamine release via dopamine and 5-HT transporters (DAT and SERT) and in vivo modulation of intracranial self-stimulation (ICSS). Here, we have assessed the effects of other steric properties of the 4-position substituents. Experimental Approach Definitive steric parameters that more explicitly focus on the volume, width and length of the MCAT 4-position substituents were assessed. In addition, homology models of human DAT and human SERT based upon the crystallized Drosophila DAT were constructed and docking studies were performed, followed by hydropathic interaction (HINT) analysis of the docking results. Key Results The potency of seven MCAT analogues at DAT was negatively correlated with the volume and maximal width of their 4-position substituents, whereas potency at SERT increased as substituent volume and length increased. SERT/DAT selectivity, as well as abuse-related drug effects in the ICSS procedure, also correlated with the same parameters. Docking solutions offered a means of visualizing these findings. Conclusions and Implications These results suggest that steric aspects of the 4-position substituents of MCAT analogues are key determinants of their action and selectivity, and that the hydrophobic nature of these substituents is involved in their potency at SERT. PMID:25522019

Urinary and sexual function outcomes among different age groups after robot-assisted laparoscopic prostatectomy.

PubMed

Mendiola, Frederick P; Zorn, Kevin C; Mikhail, Albert A; Lin, Shang; Orvieto, Marcelo A; Zagaja, Gregory P; Shalhav, Arieh L

2008-03-01

We present an age-stratified prospective assessment of urinary and sexual function of 300 patients after robot-assisted laparoscopic prostatectomy (RALP). Subjective assessment data of continence and potency were collected for different age groups (<50, 50-59, and > or =60 years old) preoperatively, and at 1, 3, 6, and 12 months after RALP. Health-related quality of life questionnaires evaluated return of baseline urinary and sexual function at the same time intervals. The three age groups included 21, 129, and 150 patients (aged <50, 50-59, and >60 years old, respectively). Using Kaplan-Meier curves, younger men achieved subjective continence significantly earlier than older age groups when age groups were compared using a 60-year-old cut-off point (P = 0.02). However, subjective continence was noted to be equal among all age groups after 1 year of follow-up. Time to recovery of subjective potency among age groups shows a significant difference in favor of the younger age group (P = 0.01) Objective urinary function is equal between age groups at all time points, while objective sexual function assessment showed a trend toward better results in the younger age group. Younger men will likely have an earlier return of continence and potency compared to older men after RALP. However, continence outcomes were noted to be equal among age groups after I year of follow-up, while younger men continue to report superior potency outcomes compared to older men over the first postoperative year. Such findings are valuable in counseling older men undergoing this procedure.

Comparison of Emetic Potencies of the 8-Ketotrichothecenes Deoxynivalenol, 15-Acetyldeoxynivalenol, 3-Acetyldeoxynivalenol, Fusarenon X, and Nivalenol

PubMed Central

Pestka, James J.

2013-01-01

Although the acute toxic effects of trichothecene mycotoxin deoxynivalenol (DON or vomitoxin), a known cause of human food poisoning, have been well characterized in several animal species, much less is known about closely related 8-ketotrichothecenes that similarly occur in cereal grains colonized by toxigenic fusaria. To address this, we compared potencies of DON, 15-acetyldeoxynivalenol (15-ADON), 3-acetyldeoxynivalenol (3-ADON), fusarenon X (FX), and nivalenol (NIV) in the mink emesis model following intraperitoneal (ip) and oral administration. All five congeners dose-dependently induced emesis by both administration methods. With increasing doses, there were marked decreases in latency to emesis with corresponding increases in emesis duration and number of emetic events. The effective doses resulting in emetic events in 50% of the animals for ip exposure to DON, 15-ADON, 3-ADON, FX, and NIV were 80, 170, 180, 70, and 60 µg/kg bw, respectively, and for oral exposure, they were 30, 40, 290, 30, and 250 µg/kg bw, respectively. The emetic potency of DON determined here was comparable to that reported in analogous studies conducted in pigs and dogs, suggesting that the mink is a suitable small animal model for investigating acute trichothecene toxicity. The use of a mouse pica model, based on the consumption of kaolin, was also evaluated as a possible surrogate for studying emesis but was found unsuitable. From a public health perspective, comparative emetic potency data derived from small animal models such as the mink should be useful for establishing toxic equivalency factors for DON and other trichothecenes. PMID:22997060

Targeted delivery of antisense oligonucleotides to hepatocytes using triantennary N-acetyl galactosamine improves potency 10-fold in mice.

PubMed

Prakash, Thazha P; Graham, Mark J; Yu, Jinghua; Carty, Rick; Low, Audrey; Chappell, Alfred; Schmidt, Karsten; Zhao, Chenguang; Aghajan, Mariam; Murray, Heather F; Riney, Stan; Booten, Sheri L; Murray, Susan F; Gaus, Hans; Crosby, Jeff; Lima, Walt F; Guo, Shuling; Monia, Brett P; Swayze, Eric E; Seth, Punit P

2014-07-01

Triantennary N-acetyl galactosamine (GalNAc, GN3: ), a high-affinity ligand for the hepatocyte-specific asialoglycoprotein receptor (ASGPR), enhances the potency of second-generation gapmer antisense oligonucleotides (ASOs) 6-10-fold in mouse liver. When combined with next-generation ASO designs comprised of short S-cEt (S-2'-O-Et-2',4'-bridged nucleic acid) gapmer ASOs, ∼ 60-fold enhancement in potency relative to the parent MOE (2'-O-methoxyethyl RNA) ASO was observed. GN3: -conjugated ASOs showed high affinity for mouse ASGPR, which results in enhanced ASO delivery to hepatocytes versus non-parenchymal cells. After internalization into cells, the GN3: -ASO conjugate is metabolized to liberate the parent ASO in the liver. No metabolism of the GN3: -ASO conjugate was detected in plasma suggesting that GN3: acts as a hepatocyte targeting prodrug that is detached from the ASO by metabolism after internalization into the liver. GalNAc conjugation also enhanced potency and duration of the effect of two ASOs targeting human apolipoprotein C-III and human transthyretin (TTR) in transgenic mice. The unconjugated ASOs are currently in late stage clinical trials for the treatment of familial chylomicronemia and TTR-mediated polyneuropathy. The ability to translate these observations in humans offers the potential to improve therapeutic index, reduce cost of therapy and support a monthly dosing schedule for therapeutic suppression of gene expression in the liver using ASOs. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

Isolation and characterization of iron chelators from turmeric (Curcuma longa): selective metal binding by curcuminoids.

PubMed

Messner, Donald J; Surrago, Christine; Fiordalisi, Celia; Chung, Wing Yin; Kowdley, Kris V

2017-10-01

Iron overload disorders may be treated by chelation therapy. This study describes a novel method for isolating iron chelators from complex mixtures including plant extracts. We demonstrate the one-step isolation of curcuminoids from turmeric, the medicinal food spice derived from Curcuma longa. The method uses iron-nitrilotriacetic acid (NTA)-agarose, to which curcumin binds rapidly, specifically, and reversibly. Curcumin, demethoxycurcumin, and bisdemethoxycurcumin each bound iron-NTA-agarose with comparable affinities and a stoichiometry near 1. Analyses of binding efficiencies and purity demonstrated that curcuminoids comprise the primary iron binding compounds recovered from a crude turmeric extract. Competition of curcuminoid binding to the iron resin was used to characterize the metal binding site on curcumin and to detect iron binding by added chelators. Curcumin-Iron-NTA-agarose binding was inhibited by other metals with relative potency: (>90% inhibition) Cu 2+  ~ Al 3+  > Zn 2+  ≥ Ca 2+  ~ Mg 2+  ~ Mn 2+ (<20% inhibition). Binding was also inhibited by pharmaceutical iron chelators (desferoxamine or EDTA) or by higher concentrations of weak iron chelators (citrate or silibinin). Investigation of the physiological effects of iron binding by curcumin revealed that curcumin uptake by cultured cells was reduced >80% by addition of iron to the media; uptake was completely restored by desferoxamine. Ranking of metals by relative potencies for blocking curcumin uptake agreed with their relative potencies in blocking curcumin binding to iron-NTA-agarose. We conclude that curcumin can selectively bind toxic metals including iron in a physiological setting, and propose inhibition of curcumin binding to iron-NTA-agarose for iron chelator screening.

Impact of chemical proportions on the acute neurotoxicity of a mixture of seven carbamates in preweanling and adult rats.

PubMed

Moser, Virginia C; Padilla, Stephanie; Simmons, Jane Ellen; Haber, Lynne T; Hertzberg, Richard C

2012-09-01

Statistical design and environmental relevance are important aspects of studies of chemical mixtures, such as pesticides. We used a dose-additivity model to test experimentally the default assumptions of dose additivity for two mixtures of seven N-methylcarbamates (carbaryl, carbofuran, formetanate, methomyl, methiocarb, oxamyl, and propoxur). The best-fitting models were selected for the single-chemical dose-response data and used to develop a combined prediction model, which was then compared with the experimental mixture data. We evaluated behavioral (motor activity) and cholinesterase (ChE)-inhibitory (brain, red blood cells) outcomes at the time of peak acute effects following oral gavage in adult and preweanling (17 days old) Long-Evans male rats. The mixtures varied only in their mixing ratios. In the relative potency mixture, proportions of each carbamate were set at equitoxic component doses. A California environmental mixture was based on the 2005 sales of each carbamate in California. In adult rats, the relative potency mixture showed dose additivity for red blood cell ChE and motor activity, and brain ChE inhibition showed a modest greater-than additive (synergistic) response, but only at a middle dose. In rat pups, the relative potency mixture was either dose-additive (brain ChE inhibition, motor activity) or slightly less-than additive (red blood cell ChE inhibition). On the other hand, at both ages, the environmental mixture showed greater-than additive responses on all three endpoints, with significant deviations from predicted at most to all doses tested. Thus, we observed different interactive properties for different mixing ratios of these chemicals. These approaches for studying pesticide mixtures can improve evaluations of potential toxicity under varying experimental conditions that may mimic human exposures.

Tautomerism, Hammett σ, and QSAR

NASA Astrophysics Data System (ADS)

Martin, Yvonne Connolly

2010-06-01

A consideration of equilibrium model-based equations suggests that tautomeric equilibria do not markedly affect observed potency if the tautomer bound represents at least 50% of the compound in solution. Tautomeric equilibria can enhance or attenuate the correlation of potency with Hammett σ. Additionally, tautomeric equilibria can lead to a correlation of potency with σ even in the absence of a correlation of binding with σ.

Quality of original and biosimilar epoetin products.

PubMed

Brinks, Vera; Hawe, Andrea; Basmeleh, Abdul H H; Joachin-Rodriguez, Liliana; Haselberg, Rob; Somsen, Govert W; Jiskoot, Wim; Schellekens, Huub

2011-02-01

To compare the quality of therapeutic erythropoietin (EPO) products, including two biosimilars, with respect to content, aggregation, isoform profile and potency. Two original products, Eprex (epoetin alpha) and Dynepo (epoetin delta), and two biosimilar products, Binocrit (epoetin alpha) and Retacrit (epoetin zeta), were compared using (1) high performance size exclusion chromatography, (2) ELISA, (3) SDS-PAGE, (4) capillary zone electrophoresis and (5) in-vivo potency. Tested EPO products differed in content, isoform composition, and potency. Of the tested products, the biosimilars have the same or even better quality as the originals. Especially, the potency of originals may significantly differ from the value on the label.

An analysis of 72% chromated glycerin used for sclerotherapy: sterility, potency, and cost after extended shelf life.

PubMed

Ghaznavi, Amir M; Nakamura, Mio; Tepper, Donna

2015-01-01

Sclerotherapy is the treatment of reticular veins and telangiectasias of the lower extremities. Sclerosants destroy endothelial tissue and expose subendothelial collagen fibers, which lead to subsequent fibrosis of vessels, thus preventing recanalization. There are several available sclerosants including sodium tetradecyl sulfate (STS), polidocanol (POL), and chromated glycerin (CG) with varying efficacy, potency, side effect profile, and cost. To identify the possible bacterial contamination and potency of CG beyond the current recommended shelf life of 3 months and to prove if CG is as cost effective as other available sclerosants. Samples of 72% CG underwent bacterial endotoxin, sterility, and potency analysis at Days 0, 24, and 183. In addition, cost comparison was performed with other commercially available sclerosants including STS and POL. No samples of CG showed any bacterial contamination. All aliquots of glycerin remained sterile at Day 14. Potency at Day 24 was 99.2%, which was the same at Day 183. Cost comparison with other sclerosants revealed that CG is lower cost per milliliter than STS and POL. Seventy-two percent CG has no contamination and maintains its reported potency up to 6 months while comparable with the cost of other commercially available sclerosants.

The use of dose-response data in a margin of exposure approach to carcinogenic risk assessment for genotoxic chemicals in food.

PubMed

Benford, Diane J

2016-05-01

Genotoxic substances are generally not permitted for deliberate use in food production. However, an appreciable number of known or suspected genotoxic substances occur unavoidably in food, e.g. from natural occurrence, environmental contamination and generation during cooking and processing. Over the past decade a margin of exposure (MOE) approach has increasingly been used in assessing the exposure to substances in food that are genotoxic and carcinogenic. The MOE is defined as a reference point on the dose-response curve (e.g. a benchmark dose lower confidences limit derived from a rodent carcinogenicity study) divided by the estimated human intake. A small MOE indicates a higher concern than a very large MOE. Whilst the MOE cannot be directly equated to risk, it supports prioritisation of substances for further research or for possible regulatory action, and provides a basis for communicating to the public. So far, the MOE approach has been confined to substances for which carcinogenicity data are available. In the absence of carcinogenicity data, evidence of genotoxicity is used only in hazard identification. The challenge to the genetic toxicology community is to develop approaches for characterising risk to human health based on data from genotoxicity studies. In order to achieve wide acceptance, it would be important to further address the issues that have been discussed in the context of dose-response modelling of carcinogenicity data in order to assign levels of concern to particular MOE values, and also whether it is possible to make generic conclusions on how potency in genotoxicity assays relates to carcinogenic potency. © Crown copyright 2015.

Development of an in vitro Bioassay for Recombinant Human Erythropoietin (rHuEPO) Based on Proliferative Stimulation of an Erythroid Cell Line and Analysis of Sialic Acid Dependent Microheterogeneity: UT-7 Cell Bioassay.

PubMed

Metta, Manoj Kumar; Malkhed, Vasavi; Tantravahi, Srinivasan; Vuruputuri, Uma; Kunaparaju, Rajkumar

2017-04-01

Determination of biological activity and its comparison with clinical behavior is important in the quality assessment of therapeutic glycoproteins. In vivo studies are usually employed for evaluating bioactivity of these glycomolecules. However, alternative methods are required to simplify the bioassay and avoid ethical issues associated with in vivo studies. Negatively charged sialic acid residues are known to be critical for in vivo bioactivity of rHuEPO. To address this need, we employed the human acute myeloid leukemia cell line UT-7 for the determination of proliferative stimulation induced by rHuEPO. Relative potencies of various intact and sugar-trimmed rHuEPO preparations were estimated using the International Standard for Human r-DNA derived EPO (87/684) as a reference for bioactivity. The cellular response was measured with a multi-channel photometer using a colorimetric microassay, based on the metabolism of the Resazurin sodium by cell viability. For a resourceful probing of physiological features of rHuEPO with significance, we obtained partly or completely desialylated rHuEPO digested by the neuraminidase enzyme without degradation of carbohydrates. Two-fold higher specific activity was shown by asialoerythropoietin in in vitro analysis compared with the sialoerythropoietin. Further, computational studies were also carried out to construct the 3D model of the erythropoietin (EPO) protein structure using standard comparative modeling methods. The quality of the model was validated using Procheck and protein structure analysis (ProSA) server tools. N-glycan units were constructed; moreover, EPO protein was glycosylated at potential glycosylation amino acid residue sites. The method described should be suitable for potency assessments of pharmaceutical formulations of rHuEPO (European Pharmacopeia, 2016).

Randomised controlled trials define shape of dose-response for Pollinex Quattro Birch allergoid immunotherapy.

PubMed

Worm, Margitta; Higenbottam, Tim; Pfaar, Oliver; Mösges, Ralph; Aberer, Werner; Gunawardena, Kulasiri; Wessiepe, Dorothea; Lee, Denise; Kramer, Matthias F; Skinner, Murray; Lees, Bev; Zielen, Stefan

2018-05-19

The Birch Allergoid, Tyrosine Adsorbate, Monophosphoryl Lipid A (POLLINEX ® Quattro Plus 1.0 ml Birch 100%) is an effective, well-tolerated short course subcutaneous immunotherapy. We performed two phase II studies to determine its optimal cumulative dose. The studies were conducted in Germany, Austria and Poland (EudraCT numbers: 2012-004336-28 PQBirch203 and 2015-000984-15 PQBirch204) using a wide range of cumulative doses. In both studies, subjects were administered 6 therapy injections weekly outside the pollen season. Conjunctival Provocation Tests were performed at screening, baseline and 3-4 weeks after completing treatment, to quantify the reduction of Total Symptom Scores (as the primary endpoint) with each cumulative dose. Multiple Comparison Procedure and Modelling analysis was used to test for the dose-response, shape of the curve, and estimation of the median effective dose (ED 50 ), a measure of potency. Statistically significant dose-responses (p<0.01 & 0.001) were seen respectively. The highest cumulative dose in PQBirch204 (27300 standardised units [SU]) approached a plateau. Potency of the PQ Birch was demonstrated by an ED 50 2723 SU, just over half the current dose. Prevalence of treatment-emergent adverse events was similar for active doses, most being short-lived and mild. Compliance was over 85% in all groups. Increasing the cumulative dose of PQ Birch 5.5-fold from 5100 to 27300 SU achieved an absolute point difference from placebo of 1.91, a relative difference 32.3% and an increase of efficacy of 50%, without compromising safety. The cumulative dose-response was confirmed to be curvilinear in shape. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Social Relationships and Health: The Meaning of Social "Connectedess" and How It Relates to Health Concerns for Rural Scottish Adolescents.

ERIC Educational Resources Information Center

Hendry, Leo B.; Reid, Marylou

2000-01-01

Discusses social belonging as both a health-related goal and an antidote for emotional crises. Examines how social connectedess represents both a content and process variable in Northern Scottish young people's discussion of their health concerns. Analyses reveal both the potency of all these concerns and participants' belief that skills acquired…

QUANTITATIVE CANCER RISK ASSESSMENT METHODOLOGY USING SHORT-TERM GENETIC BIOASSAYS: THE COMPARATIVE POTENCY METHOD

EPA Science Inventory

Quantitative risk assessment is fraught with many uncertainties. The validity of the assumptions underlying the methods employed are often difficult to test or validate. Cancer risk assessment has generally employed either human epidemiological data from relatively high occupatio...

Decoding the Structure of Abuse Potential for New Psychoactive Substances: Structure—Activity Relationships for Abuse-Related Effects of 4-Substituted Methcathinone Analogs

PubMed Central

Banks, Matthew L.

2017-01-01

Many cathinone analogs act as substrates or inhibitors at dopamine, norepinephrine, and serotonin transporters (DAT, NET, SERT, respectively). Drug selectivity at DAT vs. SERT is a key determinant of abuse potential for monoamine transporter substrates and inhibitors, such that potency at DAT > SERT is associated with high abuse potential, whereas potency at DAT < SERT is associated with low abuse potential. Quantitative structure—activity relationship (QSAR) studies with a series of 4-substituted methcathinone analogs identified volume of the 4-position substituent on the methcathinone phenyl ring as one structural determinant of both DAT vs. SERT selectivity and abuse-related behavioral effects in an intracranial self-stimulation procedure in rats. Subsequent modeling studies implicated specific amino acids in DAT and SERT that might interact with 4-substituent volume to determine effects produced by this series of cathinone analogs. These studies illustrate use of QSAR analysis to investigate pharmacology of cathinones and function of monoamine transporters. PMID:27696217

Heat Tolerance and the Peripheral Effects of Anticholinergics. 1. A Non-Invasive Method for Estimating the Cholinergic Sensitivity of the Eccrine Glands in Humans.

DTIC Science & Technology

1985-01-30

exercise history for future data segregation. All tests were performed in an air-conditioned laboratory with subjects in a thermally neutral state. RESULTS ...UNCLASSIIED K K KRANING ET AL 38 AN 85 F/G 6/15 ImmonIIIIlIIfIIIIII wI L_- pu 1 .21. o 136 - MICROCOPY RESOLUTION TEST CHART NAT WOL. BUREAU OF...used as sensitive index of anticholiinergic drug potency. Independently, we developed 1 human sweat gland assayd d+ fftf -ng from theirs in several

New analogues of oxotremorine and oxotremorine-M: estimation of their in vitro affinity and efficacy at muscarinic receptor subtypes.

PubMed

Barocelli, E; Ballabeni, V; Bertoni, S; Dallanoce, C; De Amici, M; De Micheli, C; Impicciatore, M

2000-06-30

Two subsets of tertiary amines (1a-6a) and methiodides (1b-6b) with a structural resemblance to oxotremorine and oxotremorine-M were tested at rabbit vas deferens (M1), guinea pig left atrium (M2), guinea pig ileum and urinary bladder (M3) muscarinic receptor subtypes. The pharmacological profile of the derivatives under study has been discussed by evaluating their potency, affinity and efficacy as well as the regional differences in muscarinic receptor occupancy.

Female rats are less susceptible during puberty to the lethal effects of percutaneous exposure to VX.

PubMed

Wright, Linnzi K M; Lee, Robyn B; Clarkson, Edward D; Lumley, Lucille A

2016-01-01

Nerve agents with low volatility such as VX are primarily absorbed through the skin when released during combat or a terrorist attack. The barrier function of the stratum corneum may be compromised during certain stages of development, allowing VX to more easily penetrate through the skin. However, age-related differences in the lethal potency of VX have yet to be evaluated using the percutaneous (pc) route of exposure. Thus, we estimated the 24 and 48 h median lethal dose for pc exposure to VX in male and female rats during puberty and early adulthood. Pubescent, female rats were less susceptible than both their male and adult counterparts to the lethal effects associated with pc exposure to VX possibly because of hormonal changes during that stage of development. This study emphasizes the need to control for both age and sex when evaluating the toxicological effects associated with nerve agent exposure in the rat model.

Health and Environmental Effects Profile for benzotrichloride

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-07-01

The Health and Environmental Effects Profile for benzotrichloride was prepared to support listings of hazardous constituents of a wide range of waste streams under Section 3001 of the Resource Conservation and Recovery Act (RCRA) and to provide health-related limits for emergency actions under Section 101 of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). Both published literature and information obtained from Agency program office files were evaluated as they pertained to potential human health, aquatic life and environmental effects of hazardous waste constituents. Quantitative estimates are presented provided sufficient data are available. Benzotrichloride has been evaluated as a carcinogen.more » The human carcinogen potency factor for benzotrichloride is 12.63 (mg/kg/day) for oral exposure. The Reportable Quantity (RQ) value of 1, 10, 100, 1000 or 5000 pounds is used to determine the quantity of a hazardous substance for which notification is required in the event of a release as specified by CERCLA based on chronic toxicity. The RQ value for benzotrichloride is 10.« less

Triazines facilitate neurotransmitter release of synaptic terminals located in hearts of frog (Rana ridibunda) and honeybee (Apis mellifera) and in the ventral nerve cord of a beetle (Tenebrio molitor).

PubMed

Papaefthimiou, Chrisovalantis; Zafeiridou, Georgia; Topoglidi, Aglaia; Chaleplis, George; Zografou, Stella; Theophilidis, George

2003-07-01

Three triazine herbicides, atrazine, simazine and metribuzine, and some of their major metabolites (cyanuric acid and 6-azauracil) were investigated for their action on synaptic terminals using three different isolated tissue preparations from the atria of the frog, Rana ridibunda, the heart of the honeybee, Apis mellifera macedonica, and the ventral nerve cord of the beetle, Tenebrio molitor. The results indicate that triazines facilitate the release of neurotransmitters from nerve terminals, as already reported for the mammalian central nervous system. The no observed effect concentration, the maximum concentration of the herbicide diluted in the saline that has no effect on the physiological properties of the isolated tissue, was estimated for each individual preparation. According to their relative potency, the three triazines tested can be ranked as follows: atrazine (cyanuric acid), simazine>metribuzine (6-azauracil). The action of these compounds on the cholinergic (amphibians, insects), adrenergic (amphibian) and octopaminergic (insects) synaptic terminals is discussed.

DEVELOPING RELATIVE POTENCY FACTORS FOR PESTICIDE MIXTURES: BIOSTATISTICAL ANALYSES OF JOINT DOSE-RESPONSE

EPA Science Inventory

The 1996 Food Quality Protection Act (FQPA) and the 1996 Safe Drinking Water Act Amendments (SDWAA) reaffirm previous Acts that mandate the EPA to evaluate risks posed by environmental chemical mixtures. The current report develops biological concepts and statistical procedures f...

Relative potencies of Type I and Type II pyrethroids for inhibition of spontaneous firing in neuronal networks.

EPA Science Inventory

Pyrethroids insecticides commonly used in pest control disrupt the normal function of voltage-sensitive sodium channels. We have previously demonstrated that permethrin (a Type I pyrethroid) and deltamethrin (a Type II pyrethroid) inhibit sodium channel-dependent spontaneous netw...

Shape and Steepness of Toxicological Dose-Response Relationships of Continuous Endpoints

EPA Science Inventory

A re-analysis of a large number of historical dose-response data for continuous endpoints indicates that an exponential or a Hill model with four parameters both adequately describe toxicological dose-responses. The four parameters relate to the background response, the potency o...

RELATIVE POTENCY OF ORAL ANTIGENS IN PROVOKING FOOD ALLERGY IN THE MOUS

EPA Science Inventory

Rationale: An animal model for food allergy is needed to test novel proteins produced through biotechnology for potential allergenicity. While the oral route is the most relevant method of exposure, oral tolerance is an impediment. We demonstrate that mice can distinguish...

Osteogenic potency of a 3-dimensional scaffold-free bonelike sphere of periodontal ligament stem cells in vitro.

PubMed

Singhatanadgit, Weerachai; Varodomrujiranon, Manatsanan

2013-12-01

The present study aimed to investigate the osteogenic potency of scaffold-free 3-dimensional (3D) spheres of periodontal ligament stem cells (PDLSCs). The osteogenic potency of PDLSC spheres was determined by the ability to form mineralization and to express key osteogenesis-associated genes. The alkaline phosphatase (ALP) activity and the protein content of PDLSC spheres were also measured. The 3D sphere developed its osteogenic potency in a time-dependent manner, containing approximately 10-fold higher mineralization, 5-fold higher protein content, and 4-fold greater ALP activity than those in the controls. The expression of key osteogenic genes was also upregulated in the 3D PDLSC spheres. Cellular outgrowth was observed when reintroduced into 2D culture. PDLSCs were able to undergo osteogenic differentiation in a scaffold-free 3D culture, producing bonelike mineralization in vitro. This suggests, at least in vitro, the osteogenic potency of the 3D PDLSC spheres. Copyright © 2013 Elsevier Inc. All rights reserved.

Evaluation of radioisotopic and non-radioisotopic versions of local lymph node assays for subcategorization of skin sensitizers compliant to UN GHS rev 4.

PubMed

Ha, Soojin; Ahn, Il Young; Kim, Da-Eun; Lee, Jong Kwon; Sohn, Soojung; Jung, Mi-Sook; Heo, Yong; Omori, Takashi; Bae, SeungJin; Lim, Kyung-Min

2017-04-01

Recently UN GHS has introduced the sub-categorization of skin sensitizers for which ECt (concentration estimated to induce stimulation index above threshold) of the murine local lymph node assay (LLNA) is used as criteria. Non-radioisotopic variants of LLNA, LLNA: DA, LLNA: BrdU-ELISA, LNCC and LLNA: BrdU-FCM were developed yet their utilities for potency sub-categorization are not established. Here we assessed the agreement of LLNA variants with LLNA or human data in potency sub-categorization for 22 reference substances of OECD TG429. Concordance of sub-categorization with LLNA was highest for LLNA: BrdU-FCM(91%, κ = 0.833, weighted kappa) followed by LLNA: BrdU-ELISA (82%, κ = 0.744) and LLNA: DA (73%, κ = 0.656) whereas LNCC only showed a modest association (64%, κ = 0.441). With human data, LLNA agreed best (77%) followed by LLNA: DA and LLNA: BrdU-FCM(73%), LLNA: BrdU-ELISA (68%) and LNCC(55%). Bland-Altman plot revealed that ECt's of LLNA variants largely agreed with LLNA where most values fell within 95% limit of agreement. Correlation between ECt's of LLNA and LLNA variants were high except for LNCC(pair-wise with LLNA, LLNA: DA, r = 0.848, LLNA: BrdU-ELISA, r = 0.744, LLNA: BrdU-FCM, r=0.786, and LNCC, r = 0.561 by Pearson). Collectively, these results demonstrated that LLNA variants exhibit performance comparable to LLNA in the potency sub-categorization although additional substances shall be analyzed in the future. Copyright © 2017 Elsevier Inc. All rights reserved.

Variability of cannabis potency in the Venice area (Italy): a survey over the period 2010-2012.

PubMed

Zamengo, Luca; Frison, Giampietro; Bettin, Chiara; Sciarrone, Rocco

2014-01-01

Cannabis is the most widely used illicit substance globally, with an estimated annual prevalence in 2010 of 2.6-5.0% of the adult population. Concerns have been expressed about increases in the potency of cannabis products. A high tetrahydrocannabinol (THC) content can increase anxiety, depression, and psychotic symptoms, and can increase the risk of dependence and adverse effects on the respiratory and cardiovascular systems in regular users. The aim of this study was to report statistical data about the potency of cannabis products seized in the north-east of Italy, in a geographical area centred in Venice and extending for more than 10,000  km(2) with a population of more than two million, by investigating the variability observed in THC levels of about 4000 samples of cannabis products analyzed over the period 2010-2012. Overall median THC content showed an increasing trend over the study period from about 6.0% to 8.1% (6.2-8.9% for cannabis resin, 5.1-7.6% for herbal cannabis). The variation in the THC content of individual samples was very large, ranging from 0.3% to 31% for cannabis resin and from 0.1 to 19% for herbal cannabis. Median CBN:THC ratios showed a slightly decreasing trend over the study period, from 0.09 (2010) to 0.03 (2012), suggesting an increasing freshness of submitted materials. Median CBD:THC ratios also showed a decreasing trend over the study from about 0.52 (2010) to 0.18 (2012), likely due to the increase in submissions of materials from indoor and domestic cultivation with improved breeding methods. Copyright © 2013 John Wiley & Sons, Ltd.

Potency determination of factor VIII and factor IX for new product labelling and postinfusion testing: challenges for caregivers and regulators.

PubMed

Dodt, J; Hubbard, A R; Wicks, S J; Gray, E; Neugebauer, B; Charton, E; Silvester, G

2015-07-01

A workshop organized by the European Medicines Agency and the European Directorate for the Quality of Medicines and HealthCare was held in London, UK on November 28-29, 2013, to provide an overview of the current knowledge of the characterization of new factor VIII (FVIII) and factor IX (FIX) concentrates with respect to potency assays and testing of postinfusion material. The objective was to set the basis for regulatory authorities' discussion on the most appropriate potency assay for the individual products, and European Pharmacopoeia (Ph. Eur.) discussion on whether to propose revision of the Ph. Eur. monographs with respect to potency assays in the light of information on new FVIII and FIX concentrates. The workshop showed that for all products valid assays vs. the international concentrate standards were obtained and potency could be expressed in International Units. The Ph. Eur. chromogenic potency assay gave valid assay results which correlate with in vivo functionality of rFVIII products. For some modified rFVIII products and all modified rFIX products, one-stage clotting assay methods result in different potencies depending on the activated partial thromboplastin time reagent. As a consequence, monitoring of patients' postinfusion levels is challenging but it was pointed out that manufacturers are responsible for providing the users with appropriate information for use and laboratory testing of their product. Strategies to avoid misleading determination of patents' plasma levels, e.g. information on suitable assays, laboratory standards or correction factors were discussed. © 2015 John Wiley & Sons Ltd.

Engineering high-potency R-spondin adult stem cell growth factors.

PubMed

Warner, Margaret L; Bell, Tufica; Pioszak, Augen A

2015-01-01

Secreted R-spondin proteins (RSPOs1-4) function as adult stem cell growth factors by potentiating Wnt signaling. Simultaneous binding of distinct regions of the RSPO Fu1-Fu2 domain module to the extracellular domains (ECDs) of the LGR4 G protein-coupled receptor and the ZNRF3 transmembrane E3 ubiquitin ligase regulates Wnt receptor availability. Here, we examine the molecular basis for the differing signaling strengths of RSPOs1-4 using purified RSPO Fu1-Fu2, LGR4 ECD, and ZNRF3 ECD proteins in Wnt signaling and receptor binding assays, and we engineer novel high-potency RSPOs. RSPO2/3/4 had similar signaling potencies that were stronger than that of RSPO1, whereas RSPO1/2/3 had similar efficacies that were greater than that of RSPO4. The RSPOs bound LGR4 with affinity rank order RSPO4 > RSPO2/3 > RSPO1 and ZNRF3 with affinity rank order RSPO2/3 > > RSPO1 > RSPO4. An RSPO2-4 chimera combining RSPO2 ZNRF3 binding with RSPO4 LGR4 binding was a "Superspondin" that exhibited enhanced ternary complex formation and 10-fold stronger signaling potency than RSPO2 and efficacy equivalent to RSPO2. An RSPO4-1 chimera combining RSPO4 ZNRF3 binding with RSPO1 LGR4 binding was a "Poorspondin" that exhibited signaling potency similar to RSPO1 and efficacy equivalent to RSPO4. Conferring increased ZNRF3 binding upon RSPO4 with amino acid substitutions L56F, I58L, and I63M enhanced its signaling potency and efficacy. Our results reveal the molecular basis for RSPOs1-4 activity differences and suggest that signaling potency is determined by ternary complex formation ability, whereas efficacy depends on ZNRF3 recruitment. High-potency RSPOs may be of value for regenerative medicine and/or therapeutic applications. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

Probabilistic dose-response modeling: case study using dichloromethane PBPK model results.

PubMed

Marino, Dale J; Starr, Thomas B

2007-12-01

A revised assessment of dichloromethane (DCM) has recently been reported that examines the influence of human genetic polymorphisms on cancer risks using deterministic PBPK and dose-response modeling in the mouse combined with probabilistic PBPK modeling in humans. This assessment utilized Bayesian techniques to optimize kinetic variables in mice and humans with mean values from posterior distributions used in the deterministic modeling in the mouse. To supplement this research, a case study was undertaken to examine the potential impact of probabilistic rather than deterministic PBPK and dose-response modeling in mice on subsequent unit risk factor (URF) determinations. Four separate PBPK cases were examined based on the exposure regimen of the NTP DCM bioassay. These were (a) Same Mouse (single draw of all PBPK inputs for both treatment groups); (b) Correlated BW-Same Inputs (single draw of all PBPK inputs for both treatment groups except for bodyweights (BWs), which were entered as correlated variables); (c) Correlated BW-Different Inputs (separate draws of all PBPK inputs for both treatment groups except that BWs were entered as correlated variables); and (d) Different Mouse (separate draws of all PBPK inputs for both treatment groups). Monte Carlo PBPK inputs reflect posterior distributions from Bayesian calibration in the mouse that had been previously reported. A minimum of 12,500 PBPK iterations were undertaken, in which dose metrics, i.e., mg DCM metabolized by the GST pathway/L tissue/day for lung and liver were determined. For dose-response modeling, these metrics were combined with NTP tumor incidence data that were randomly selected from binomial distributions. Resultant potency factors (0.1/ED(10)) were coupled with probabilistic PBPK modeling in humans that incorporated genetic polymorphisms to derive URFs. Results show that there was relatively little difference, i.e., <10% in central tendency and upper percentile URFs, regardless of the case evaluated. Independent draws of PBPK inputs resulted in the slightly higher URFs. Results were also comparable to corresponding values from the previously reported deterministic mouse PBPK and dose-response modeling approach that used LED(10)s to derive potency factors. This finding indicated that the adjustment from ED(10) to LED(10) in the deterministic approach for DCM compensated for variability resulting from probabilistic PBPK and dose-response modeling in the mouse. Finally, results show a similar degree of variability in DCM risk estimates from a number of different sources including the current effort even though these estimates were developed using very different techniques. Given the variety of different approaches involved, 95th percentile-to-mean risk estimate ratios of 2.1-4.1 represent reasonable bounds on variability estimates regarding probabilistic assessments of DCM.

An endogenous capsaicin-like substance with high potency at recombinant and native vanilloid VR1 receptors

PubMed Central

Huang, Susan M.; Bisogno, Tiziana; Trevisani, Marcello; Al-Hayani, Abdulmonem; De Petrocellis, Luciano; Fezza, Filomena; Tognetto, Michele; Petros, Timothy J.; Krey, Jocelyn F.; Chu, Constance J.; Miller, Jeffrey D.; Davies, Stephen N.; Geppetti, Pierangelo; Walker, J. Michael; Di Marzo, Vincenzo

2002-01-01

The vanilloid receptor VR1 is a nonselective cation channel that is most abundant in peripheral sensory fibers but also is found in several brain nuclei. VR1 is gated by protons, heat, and the pungent ingredient of “hot” chili peppers, capsaicin. To date, no endogenous compound with potency at this receptor comparable to that of capsaicin has been identified. Here we examined the hypothesis, based on previous structure-activity relationship studies and the availability of biosynthetic precursors, that N-arachidonoyl-dopamine (NADA) is an endogenous “capsaicin-like” substance in mammalian nervous tissues. We found that NADA occurs in nervous tissues, with the highest concentrations being found in the striatum, hippocampus, and cerebellum and the lowest concentrations in the dorsal root ganglion. We also gained evidence for the existence of two possible routes for NADA biosynthesis and mechanisms for its inactivation in rat brain. NADA activates both human and rat VR1 overexpressed in human embryonic kidney (HEK)293 cells, with potency (EC50 ≈ 50 nM) and efficacy similar to those of capsaicin. Furthermore, NADA potently activates native vanilloid receptors in neurons from rat dorsal root ganglion and hippocampus, thereby inducing the release of substance P and calcitonin gene-related peptide (CGRP) from dorsal spinal cord slices and enhancing hippocampal paired-pulse depression, respectively. Intradermal NADA also induces VR1-mediated thermal hyperalgesia (EC50 = 1.5 ± 0.3 μg). Our data demonstrate the existence of a brain substance similar to capsaicin not only with respect to its chemical structure but also to its potency at VR1 receptors. PMID:12060783

Additivity of Pyrethroid Actions on Sodium Influx in Cerebrocortical Neurons in Primary Culture

PubMed Central

Cao, Zhengyu; Shafer, Timothy J.; Crofton, Kevin M.; Gennings, Chris

2011-01-01

Background: Pyrethroid insecticides bind to voltage-gated sodium channels and modify their gating kinetics, thereby disrupting neuronal function. Although previous work has tested the additivity of pyrethroids in vivo, this has not been assessed directly at the primary molecular target using a functional measure. Objectives: We investigated the potency and efficacy of 11 structurally diverse food-use pyrethroids to evoke sodium (Na+) influx in neurons and tested the hypothesis of dose additivity for a mixture of these same 11 compounds. Methods: We determined pyrethroid-induced increases in Na+ influx in primary cultures of cerebrocortical neurons using the Na+-sensitive dye sodium-binding benzofuran isophthalate (SBFI). Concentration-dependent responses for 11 pyrethroids were determined, and the response to dilutions of a mixture of all 11 compounds at an equimolar mixing ratio was assessed. Additivity was tested assuming a dose-additive model. Results: Seven pyrethroids produced concentration-dependent, tetrodotoxin-sensitive Na+ influx. The rank order of potency was deltamethrin > S-bioallethrin > β-cyfluthrin > λ-cyhalothrin > esfenvalerate > tefluthrin > fenpropathrin. Cypermethrin and bifenthrin produced modest increases in Na+ influx, whereas permethrin and resmethrin were inactive. When all 11 pyrethroids were present at an equimolar mixing ratio, their actions on Na+ influx were consistent with a dose-additive model. Conclusions: These data provide in vitro relative potency and efficacy measurements for 7 pyrethroid compounds in intact mammalian neurons. Despite differences in individual compound potencies, we found the action of a mixture of all 11 pyrethroids to be additive when we used an appropriate statistical model. These results are consistent with a previous report of the additivity of pyrethroids in vivo. PMID:21665567

Determination of influenza B identity and potency in quadrivalent inactivated influenza vaccines using lineage-specific monoclonal antibodies

PubMed Central

Verma, Swati; Soto, Jackeline; Vasudevan, Anupama; Schmeisser, Falko; Alvarado-Facundo, Esmeralda; Wang, Wei; Weiss, Carol D.

2017-01-01

Co-circulation of two antigenically and genetically distinct lineages of influenza B virus, represented by prototype viruses B/Victoria/2/1987 and B/Yamagata/16/1988, has led to the development of quadrivalent influenza vaccines that contain two influenza B antigens. The inclusion of two influenza B antigens presents challenges for the production and regulation of inactivated quadrivalent vaccines, including the potential for cross-reactivity of the reagents used in identity and potency assays because of the relative close relatedness of the hemagglutinin (HA) from the two virus lineages. Monoclonal antibodies (mAbs) specific for the two lineages of influenza B HA were generated and characterized and used to set-up simple identity tests that distinguish the influenza B antigens in inactivated trivalent and quadrivalent vaccines. The lineage-specific mAbs bound well to the HA of influenza B strains included in influenza vaccines over a period of more than 10 years, suggesting that identity tests using such lineage-specific mAbs would not necessarily have to be updated with every influenza B vaccine strain change. These lineage-specific mAbs were also used in an antibody capture ELISA format to quantify HA in vaccine samples, including monovalent, trivalent, and quadrivalent vaccine samples from various manufacturers. The results demonstrated correlation with HA values determined by the traditional single radial immunodiffusion (SRID) assay. Further, the antibody-capture ELISA was able to distinguish heat-stressed vaccine from unstressed vaccine, and was similar to the SRID in quantifying the resultant loss of potency. These mAb reagents should be useful for further development of antibody-based alternative influenza B identity and potency assays. PMID:28423025

Determination of influenza B identity and potency in quadrivalent inactivated influenza vaccines using lineage-specific monoclonal antibodies.

PubMed

Verma, Swati; Soto, Jackeline; Vasudevan, Anupama; Schmeisser, Falko; Alvarado-Facundo, Esmeralda; Wang, Wei; Weiss, Carol D; Weir, Jerry P

2017-01-01

Co-circulation of two antigenically and genetically distinct lineages of influenza B virus, represented by prototype viruses B/Victoria/2/1987 and B/Yamagata/16/1988, has led to the development of quadrivalent influenza vaccines that contain two influenza B antigens. The inclusion of two influenza B antigens presents challenges for the production and regulation of inactivated quadrivalent vaccines, including the potential for cross-reactivity of the reagents used in identity and potency assays because of the relative close relatedness of the hemagglutinin (HA) from the two virus lineages. Monoclonal antibodies (mAbs) specific for the two lineages of influenza B HA were generated and characterized and used to set-up simple identity tests that distinguish the influenza B antigens in inactivated trivalent and quadrivalent vaccines. The lineage-specific mAbs bound well to the HA of influenza B strains included in influenza vaccines over a period of more than 10 years, suggesting that identity tests using such lineage-specific mAbs would not necessarily have to be updated with every influenza B vaccine strain change. These lineage-specific mAbs were also used in an antibody capture ELISA format to quantify HA in vaccine samples, including monovalent, trivalent, and quadrivalent vaccine samples from various manufacturers. The results demonstrated correlation with HA values determined by the traditional single radial immunodiffusion (SRID) assay. Further, the antibody-capture ELISA was able to distinguish heat-stressed vaccine from unstressed vaccine, and was similar to the SRID in quantifying the resultant loss of potency. These mAb reagents should be useful for further development of antibody-based alternative influenza B identity and potency assays.

Mechanism of action of a nanomolar potent, allosteric antagonist of the thyroid-stimulating hormone receptor

PubMed Central

van Koppen, Chris J; de Gooyer, Marcel E; Karstens, Willem-Jan; Plate, Ralf; Conti, Paolo GM; van Achterberg, Tanja AE; van Amstel, Monique GA; Brands, Jolanda HGM; Wat, Jesse; Berg, Rob JW; Lane, J Robert D; Miltenburg, Andre MM; Timmers, C Marco

2012-01-01

BACKGROUND AND PURPOSE Graves' disease (GD) is an autoimmune disease in which the thyroid is overactive, producing excessive amounts of thyroid hormones, caused by thyroid-stimulating hormone (TSH) receptor-stimulating immunoglobulins (TSIs). Many GD patients also suffer from thyroid eye disease (Graves' ophthalmopathy or GO), as TSIs also activate TSH receptors in orbital tissue. We recently developed low molecular weight (LMW) TSH receptor antagonists as a novel therapeutic strategy for the treatment of GD and GO. Here, we determined the molecular pharmacology of a prototypic, nanomolar potent LMW TSH receptor antagonist, Org 274179-0. EXPERIMENTAL APPROACH Using CHO cells heterogeneously expressing human TSH receptors and rat FRTL-5 cells endogenously expressing rat TSH receptors, we determined the potency and efficacy of Org 274179-0 at antagonizing TSH- and TSI-induced TSH receptor signalling and its cross-reactivity at related follicle-stimulating hormone and luteinizing hormone receptors. We analysed the allosteric mode of interaction of Org 274179-0 and determined whether it is an inverse agonist at five naturally occurring, constitutively active TSH receptor mutants. KEY RESULTS Nanomolar concentrations of Org 274179-0 completely inhibited TSH (and TSI)-mediated TSH receptor activation with little effect on the potency of TSH, in accordance with an allosteric mechanism of action. Conversely, increasing levels of TSH receptor stimulation only marginally reduced the antagonist potency of Org 274179-0. Org 274179-0 fully blocked the increased basal activity of all the constitutively active TSH receptor mutants tested with nanomolar potencies. CONCLUSIONS AND IMPLICATIONS Nanomolar potent TSH receptor antagonists like Org 274179-0 have therapeutic potential for the treatment of GD and GO. PMID:22014107

Technological Implementation of Renewable Energy in Rural-Isolated Areas and Small-Medium Islands in Indonesia: Problem Mapping And Preliminary Surveys of Total People Participation in a Local Wind Pump Water Supply

NASA Astrophysics Data System (ADS)

Taufik, Ahmad

2007-10-01

This article discusses a formulation of problem mapping and preliminary surveys of total people participation in a local wind pump (LWP) water supply in term of technological implementation of renewable energy (RE) in rural-isolated areas and small-medium islands in Indonesia. The formulation was constructed in order to enhance and to promote the local product of RE across Indonesia. It was also addressed to accommodate local potencies, barriers and opportunities into a priority map. Moreover, it was designed into five aspects such as (1) local technology of the RE: a case of pilot project of the LWP; (2) environmental-cultural aspects related to global issues of energy-renewable energy; (3) potencies and barriers corresponding to local, national, regional and international contents; (4) education and training and (5) gender participation. To focus the formulation, serial preliminary surveys were conducted in five major areas, namely: (1) survey on support and barrier factors of the aspects; (2) strategic planning model, a concept A-B-G which stands for Academician-Business people-Government; (3) survey on background based knowledge on energy conservation; (4) survey on gender participation in energy conservation and (5) survey on local stakeholder involvement. Throughout the surveys, it has been notified that the concept needs to be developed to any level of its component since its elements were identified in tolerance values such as high potency value of the LWP development (95%); a strong potency of rural area application (88%); a medium background of energy, energy conservation (EC) identified in a range of 56%-72%, sufficient support from local stakeholders and gender participation.

Antimicrobial potency of cationic antimicrobial peptides can be predicted from their amino acid composition: Application to the detection of "cryptic" antimicrobial peptides.

PubMed

Pane, Katia; Durante, Lorenzo; Crescenzi, Orlando; Cafaro, Valeria; Pizzo, Elio; Varcamonti, Mario; Zanfardino, Anna; Izzo, Viviana; Di Donato, Alberto; Notomista, Eugenio

2017-04-21

Cationic antimicrobial peptides (CAMPs) are essential components of innate immunity. Here we show that antimicrobial potency of CAMPs is linearly correlated to the product C m H n L where C is the net charge of the peptide, H is a measure of its hydrophobicity and L its length. Exponents m and n define the relative contribution of charge and hydrophobicity to the antimicrobial potency. Very interestingly the values of m and n are strain specific. The ratio n/(m+n) can vary between ca. 0.5 and 1, thus indicating that some strains are sensitive to highly charged peptides, whereas others are particularly susceptible to more hydrophobic peptides. The slope of the regression line describing the correlation "antimicrobial potency"/"C m H n L product" changes from strain to strain indicating that some strains acquired a higher resistance to CAMPs than others. Our analysis provides also an effective computational strategy to identify CAMPs included inside the structure of larger proteins or precursors, which can be defined as "cryptic" CAMPs. We demonstrate that it is not only possible to identify and locate with very good precision the position of cryptic peptides, but also to analyze the internal structure of long CAMPs, thus allowing to draw an accurate map of the molecular determinants of their antimicrobial activity. A spreadsheet, provided in the Supplementary material, allows performing the analysis of protein sequences. Our strategy is also well suited to analyze large pools of sequences, thus significantly improving the identification of new CAMPs and the study of innate immunity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structural implications of hERG K+ channel block by a high-affinity minimally structured blocker

PubMed Central

Helliwell, Matthew V.; Zhang, Yihong; El Harchi, Aziza; Du, Chunyun; Hancox, Jules C.; Dempsey, Christopher E.

2018-01-01

Cardiac potassium channels encoded by human ether-à-go-go–related gene (hERG) are major targets for structurally diverse drugs associated with acquired long QT syndrome. This study characterized hERG channel inhibition by a minimally structured high-affinity hERG inhibitor, Cavalli-2, composed of three phenyl groups linked by polymethylene spacers around a central amino group, chosen to probe the spatial arrangement of side chain groups in the high-affinity drug-binding site of the hERG pore. hERG current (IhERG) recorded at physiological temperature from HEK293 cells was inhibited with an IC50 of 35.6 nm with time and voltage dependence characteristic of blockade contingent upon channel gating. Potency of Cavalli-2 action was markedly reduced for attenuated inactivation mutants located near (S620T; 54-fold) and remote from (N588K; 15-fold) the channel pore. The S6 Y652A and F656A mutations decreased inhibitory potency 17- and 75-fold, respectively, whereas T623A and S624A at the base of the selectivity filter also decreased potency (16- and 7-fold, respectively). The S5 helix F557L mutation decreased potency 10-fold, and both F557L and Y652A mutations eliminated voltage dependence of inhibition. Computational docking using the recent cryo-EM structure of an open channel hERG construct could only partially recapitulate experimental data, and the high dependence of Cavalli-2 block on Phe-656 is not readily explainable in that structure. A small clockwise rotation of the inner (S6) helix of the hERG pore from its configuration in the cryo-EM structure may be required to optimize Phe-656 side chain orientations compatible with high-affinity block. PMID:29545312

Study of the effect of thiols on the vasodilatory potency of S-nitrosothiols by using a modified aortic ring assay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giustarini, Daniela, E-mail: giustarini@unisi.it; Tsikas, Dimitrios, E-mail: tsikas.dimitros@mh-hannover.de; Rossi, Ranieri, E-mail: ranieri@unisi.it

2011-10-15

Both low-molecular-mass thiols (LMM-SH) and protein thiols (P-SH) can modulate the biological activity of S-nitrosothiols (RSNO) via S-transnitrosation reactions. It has been difficult to evaluate the entity of this effect in blood circulation by in vitro assays with isolated aorta rings so far, because media rich in proteins cannot be used due to the foaming as a consequence of the needed gas bubbling. We have modified the original apparatus for organ bioassay in order to minimize foaming and to increase analytical performance. By using this modified bioassay we investigated the vasodilatory potency of various endogenous RSNOs in the presence ofmore » physiologically relevant concentrations of albumin and LMM-SH. Our results show that the sulfhydryl group of the cysteine moiety of albumin and LMM-SH has a dramatic effect on the vasodilatory potency of RSNO. Considering the equilibrium constants for S-transnitrosation reactions and the concentration of P-SH and LMM-SH we measured in healthy humans (aged 18-85 years), we infer that the age-dependency of hematic levels of LMM-SH may have a considerable impact in RSNO-mediated vasodilation. S-Nitrosoproteins such as S-nitrosoalbumin may constitute a relatively silent and constant amount of circulating RSNO. On the other hand, LMM-SH may mediate and control the biological actions of S-nitrosoproteins via S-transnitrosation reactions, by forming more potent nitric oxide-releasing LMM-S-nitrosothiols. Lifestyle habits, status of health and individual age are proven factors that, in turn, may influence the concentration of these compounds. These aspects should be taken into consideration when testing the vasodilatory effects of RSNO in pre-clinical studies. - Highlights: > A modification of the organ chamber apparatus for aortic ring bioassays is proposed. > The new apparatus can work in the presence of albumin at physiological concentrations. > Potency of RSNOs was studied in the presence of albumin and low molecular mass -SH. > Plasma thiol levels decrease with age. > Potency of RSNOs varies in dependence of age and more in general of plasma thiol status.« less

In vitro immunotherapy potency assays using real-time cell analysis

PubMed Central

Cerignoli, Fabio; Abassi, Yama A.; Lamarche, Brandon J.; Guenther, Garret; Santa Ana, David; Guimet, Diana; Zhang, Wen; Zhang, Jing

2018-01-01

A growing understanding of the molecular interactions between immune effector cells and target tumor cells, coupled with refined gene therapy approaches, are giving rise to novel cancer immunotherapeutics with remarkable efficacy in the clinic against both solid and liquid tumors. While immunotherapy holds tremendous promise for treatment of certain cancers, significant challenges remain in the clinical translation to many other types of cancers and also in minimizing adverse effects. Therefore, there is an urgent need for functional potency assays, in vitro and in vivo, that could model the complex interaction of immune cells with tumor cells and can be used to rapidly test the efficacy of different immunotherapy approaches, whether it is small molecule, biologics, cell therapies or combinations thereof. Herein we report the development of an xCELLigence real-time cytolytic in vitro potency assay that uses cellular impedance to continuously monitor the viability of target tumor cells while they are being subjected to different types of treatments. Specialized microtiter plates containing integrated gold microelectrodes enable the number, size, and surface attachment strength of adherent target tumor cells to be selectively monitored within a heterogeneous mixture that includes effector cells, antibodies, small molecules, etc. Through surface-tethering approach, the killing of liquid cancers can also be monitored. Using NK92 effector cells as example, results from RTCA potency assay are very well correlated with end point data from image-based assays as well as flow cytometry. Several effector cells, i.e., PBMC, NK, CAR-T were tested and validated as well as biological molecules such as Bi-specific T cell Engagers (BiTEs) targeting the EpCAM protein expressed on tumor cells and blocking antibodies against the immune checkpoint inhibitor PD-1. Using the specifically designed xCELLigence immunotherapy software, quantitative parameters such as KT50 (the amount of time it takes to kill 50% of the target tumor cells) and % cytolysis are calculated and used for comparing the relative efficacy of different reagents. In summary, our results demonstrate the xCELLigence platform to be well suited for potency assays, providing quantitative assessment with high reproducibility and a greatly simplified work flow. PMID:29499048

Acyl Chain-Dependent Effect of Lysophosphatidylcholine on Endothelium-Dependent Vasorelaxation

PubMed Central

Rao, Shailaja P.; Riederer, Monika; Lechleitner, Margarete; Hermansson, Martin; Desoye, Gernot; Hallström, Seth; Graier, Wolfgang F.; Frank, Saša

2013-01-01

Previously we identified palmitoyl-, oleoyl-, linoleoyl-, and arachidonoyl-lysophosphatidylcholine (LPC 16:0, 18:1, 18:2 and 20:4) as the most prominent LPC species generated by endothelial lipase (EL). In the present study, we examined the impact of those LPC on acetylcholine (ACh)- induced vascular relaxation. All tested LPC attenuated ACh-induced relaxation, measured ex vivo, using mouse aortic rings and wire myography. The rank order of potency was as follows: 18:2>20:4>16:0>18:1. The attenuating effect of LPC 16:0 on relaxation was augmented by indomethacin-mediated cyclooxygenase (COX)-inhibition and CAY10441, a prostacyclin (PGI2)- receptor (IP) antagonist. Relaxation attenuated by LPC 20:4 and 18:2 was improved by indomethacin and SQ29548, a thromboxane A2 (TXA2)- receptor antagonist. The effect of LPC 20:4 could also be improved by TXA2- and PGI2-synthase inhibitors. As determined by EIA assays, the tested LPC promoted secretion of PGI2, TXA2, PGF2α, and PGE2, however, with markedly different potencies. LPC 16:0 was the most potent inducer of superoxide anion production by mouse aortic rings, followed by LPC 18:2, 20:4 and 18:1, respectively. The strong antioxidant tempol recovered relaxation impairment caused by LPC 18:2, 18:1 and 20:4, but not by LPC 16:0. The tested LPC attenuate ACh-induced relaxation through induction of proconstricting prostanoids and superoxide anions. The potency of attenuating relaxation and the relative contribution of underlying mechanisms are strongly related to LPC acyl-chain length and degree of saturation. PMID:23741477

Receptors for substance P. II. Classification by agonist fragments and homologues.

PubMed

Regoli, D; Mizrahi, J; D'Orléans-Juste, P; Escher, E

1984-01-27

Substance P (SP), a series of C-terminal fragments, SP-(2-11), SP-(3-11), SP-(4-11), SP-(5-11), SP-(6-11), SP-(7-11) and the homologues physalaemin, eledoisin and kassinin were used to measure the order of potency of agonists in five pharmacological preparations. These are: the guinea pig ileum, the guinea pig trachea, the rabbit mesenteric vein, the dog common carotid artery and the rabbit aorta. Apparent affinities (pD2) and relative activities of SP-related peptides were measured in the absence and presence of antagonists (a mixture of atropine, indomethacin and diphenhydramine) in the guinea pig ileum and the rabbit mesenteric vein, in the absence and presence of indomethacin in the guinea pig trachea and in tissues with intact endothelium (the dog carotid artery and the rabbit aorta). The orders of potency measured in the absence and presence of antagonists in the guinea pig ileum were different, while no major changes were noted in two other preparations, namely the guinea pig trachea and the rabbit mesenteric vein. The order of potency of agonists determined with homologues revealed the existence of three major patterns namely: kassinin greater than eledoisin greater than physalaemin = SP in the guinea pig trachea and the rabbit mesenteric vein, SP = physalaemin greater than eledoisin greater than kassinin in the arterial smooth muscle of the dog carotid artery and the rabbit aorta and physalaemin greater than kassinin greater than eledoisin greater than SP in the guinea pig ileum treated with antagonists.(ABSTRACT TRUNCATED AT 250 WORDS)

Degradative enzymes modulate airway responses to intravenous neurokinins A and B.

PubMed

Shore, S A; Drazen, J M

1989-12-01

We studied the effects of the neutral endopeptidase (NEP) inhibitor thiorphan (1.7 mg/kg iv) and the angiotensin-converting enzyme (ACE) inhibitor captopril (5.7 mg/kg iv) on airway responses to rapid intravenous infusions of neurokinin A (NKA) and neurokinin B (NKB) in anesthetized, mechanically ventilated guinea pigs. The dose of NKA required to decrease pulmonary conductance to 50% of its base-line value (ED50GL) was fivefold less (P less than 0.0001) in animals treated with thiorphan compared with controls. NKA1-8, a product resulting from cleavage of NKA by NEP, had no bronchoconstrictor activity. Similar results were obtained by using NKB as the bronchoconstricting agent. Captopril had no significant effect on airway responses to NKA or NKB. In contrast, both thiorphan and captopril decrease the ED50GL for substance P (SP). We also compared the relative bronchoconstrictor potency of NKA, NKB, and SP. In control animals, the rank order of ED50GL values was NKA much less than NKB = SP. NKA also caused a more prolonged bronchoconstriction than SP or NKB. Thiorphan had no effect on the rank order of bronchoconstrictor potency, but in animals treated with captopril, the rank order of ED50GL values was altered to NKA less than SP less than NKB. These results suggest that degradation of NKA and NKB by NEP but not by ACE is an important determinant of the bronchoconstriction induced by these peptides. The degradation by ACE of SP but not NKA or NKB influences the observed relative potency of the three tachykinins as bronchoactive agents.

Structure-Activity Relationship Studies Using Natural and Synthetic Okadaic Acid/Dinophysistoxin Toxins.

PubMed

Twiner, Michael J; Doucette, Gregory J; Pang, Yucheng; Fang, Chao; Forsyth, Craig J; Miles, Christopher O

2016-11-04

Okadaic acid (OA) and the closely related dinophysistoxins (DTXs) are algal toxins that accumulate in shellfish and are known serine/threonine protein phosphatase (ser/thr PP) inhibitors. Phosphatases are important modulators of enzyme activity and cell signaling pathways. However, the interactions between the OA/DTX toxins and phosphatases are not fully understood. This study sought to identify phosphatase targets and characterize their structure-activity relationships (SAR) with these algal toxins using a combination of phosphatase activity and cytotoxicity assays. Preliminary screening of 21 human and yeast phosphatases indicated that only three ser/thr PPs (PP2a, PP1, PP5) were inhibited by physiologically saturating concentrations of DTX2 (200 nM). SAR studies employed naturally-isolated OA, DTX1, and DTX2, which vary in degree and/or position of methylation, in addition to synthetic 2- epi -DTX2. OA/DTX analogs induced cytotoxicity and inhibited PP activity with a relatively conserved order of potency: OA = DTX1 ≥ DTX2 > 2- epi -DTX. The PPs were also differentially inhibited with sensitivities of PP2a > PP5 > PP1. These findings demonstrate that small variations in OA/DTX toxin structures, particularly at the head region (i.e., C1/C2), result in significant changes in toxicological potency, whereas changes in methylation at C31 and C35 (tail region) only mildly affect potency. In addition to this being the first study to extensively test OA/DTX analogs' activities towards PP5, these data will be helpful for accurately determining toxic equivalence factors (TEFs), facilitating molecular modeling efforts, and developing highly selective phosphatase inhibitors.

The Intercostal NMJ Assay: a new alternative to the conventional LD50 assay for the determination of the therapeutic potency of botulinum toxin preparations.

PubMed

Huber, Alexander; France, Richard M; Riccalton-Banks, Lisa; McLaren, Jane; Cox, Helen; Quirk, Robin A; Shakesheff, Kevin M; Thompson, David; Panjwani, Naveed; Shipley, Sarah; Pickett, Andy

2008-05-01

Therapeutic botulinum neurotoxin type A preparations have found an increasing number of clinical uses for a large variety of neuromuscular disorders and dermatological conditions. The accurate determination of potency in the clinical application of botulinum toxins is critical to ensuring clinical efficacy and safety, and is currently achieved by using a lethal dose (LD50) assay in mice. Ethical concerns and operational constraints associated with this assay have prompted the development of alternative assay systems that could potentially lead to its replacement. As one such alternative, we describe the development and evaluation of a novel ex vivo assay (the Intercostal Neuromuscular Junction [NMJ] Assay), which uses substantially fewer animals and addresses ethical concerns associated with the LD50 assay. The assay records the decay of force from electrically-stimulated muscle tissue sections in response to the toxin, and thus combines the important mechanisms of receptor binding, translocation, and the enzymatic action of the toxin molecule. Toxin application leads to a time-related and dose-related reduction in contractile force. A regression model describing the relationship between the applied dose and force decay was determined statistically, and was successfully tested as able to correctly predict the potency of an unknown sample. The tissue sections used were found to be highly reproducible, as determined through the innervation pattern and the localisation of NMJs in situ. Furthermore, the efficacy of the assay protocol to successfully deliver the test sample to the cellular target sites, was critically assessed by using molecular tracer molecules.

RELATIVE POTENCIES OF MINERAL FIBERS IN VIVO: FERROACTINOLITE FROM TACONITE

EPA Science Inventory

In the early 1970s EPA provided the scientific basis for the Federal Government's lead in the Reserve Mining Case. This historic case resulted in cessation of the discharge of taconite tailings into Lake Superior and controls on air and water emissions of microscopic amphibole fi...

FACTORS THAT INFLUENCE THE RELATIVE POTENCY OF DIESEL EXHAUST PARTICLES AS ADJUVANTS IN ALLERGIC AIRWAY DISEASE

EPA Science Inventory

Description: Studies have shown that diesel exhaust particles (DEP) worsen respiratory diseases including allergic asthma. The adjuvant effects of DEP in the airways have been widely reported; however, the precise determinants and mechanisms of these effects are ill-defined. S...

Synthesis and biological evaluation of vinylogous combretastatin A-4 derivatives.

PubMed

Kaffy, Julia; Pontikis, Renée; Florent, Jean-Claude; Monneret, Claude

2005-07-21

Stereospecific syntheses of the Z-E and E-Z vinylogues of combretastatin A-4, and two B-ring related analogues, were achieved through a Suzuki-Miyaura coupling. As compared to CA4, the derivative with a phenyl moiety has shown increased potency in its ability to inhibit tubulin polymerisation.

Use of NMR-based Metabolite Profiling to Study Responses of Fathead Minnows Exposed to the Potent Androgen 17β-trenbolone

EPA Science Inventory

Exposure of organisms in aquatic ecosystems to chemicals which possess endocrine disrupting properties can produce numerous detrimental effects. Furthermore, due to the potency of these chemicals, even relatively low level exposures can reduce fitness. As a result, classical expo...

PREDICTING REGIONAL ALLERGY HOTSPOTS IN FUTURE CLIMATE SCENARIOS – PUTTING THE WHERE & WHEN ON WHEEZING

EPA Science Inventory

This research addresses both the effects and mechanisms by which current and future climate conditions affect the risk factors related to allergic airway disease in humans. Our intensive sampling of pollen production, output, and potency in ecologically distinct ragweed popul...

African American Daughter-Mother Relations and Teenage Pregnancy: Two Faces of Premarital Teenage Pregnancy.

ERIC Educational Resources Information Center

Scott, Joseph W.

1993-01-01

Examines mother-daughter relationships and teenage pregnancy prevention in 153 school-aged mothers. The consistent finding is that negative daughter-mother relationships foster earlier first pregnancies, whereas positive relationships resulted in later-age pregnancies. Consistently positive relationships are second in potency for delaying or…

AN ALTERNATIVE METHOD FOR ESTABLISHING TEFS FOR DIOXIN-LIKE COMPOUNDS. PART 1. EVALUATION OF DECISION ANALYSIS METHODS FOR USE IN WEIGHTING RELATIVE POTENCY DATA

EPA Science Inventory

A number of investigators have recently examined the utility of applying probabilistic techniques in the derivation of toxic equivalency factors (TEFs) for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (...

Development of a Relative Potency Factor (Rpf) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures (External Review Draft)

EPA Science Inventory

EPA is conducting a peer review and public comment of the scientific basis supporting the human health hazard and dose-response assessment of polycyclic aromatic hydrocarbon (PAH) mixtures that when finalized will appear on the Integrated Risk Information System (IRIS) database. ...

MUTAGENIC AND CARCINOGENIC POTENCY OF EXTRACTS OF DIESEL AND RELATED ENVIRONMENTAL EMISSIONS: SUMMARY AND DISCUSSION OF THE RESULTS

EPA Science Inventory

The proposed conversion from gasoline powered automobiles to diesel powered vehicles has prompted the Environmental Protection Agency to evaluate the potential health effects associated with exposure to diesel emissions. At present, there is no direct epidemiological link between...

Optimizing Dose Characterizations for Measurement of in vivo Relative Potencies of Mineral Fibers

EPA Science Inventory

NHEERL and OSWER representatives were invited to Libby, MT, for meetings on September 26-27, 2007, to discuss research addressing the health effects of asbestos contamination of that community. Vermiculite ore mined for 70 years near the town contained substantial amounts of amp...

Relative Potency of Teacher Attitudes Toward Black and Retarded Children.

ERIC Educational Resources Information Center

Clifford, Miriam

The attitudes of nine teachers in three graded, open classrooms toward their home-base pupils were measured using Schaefer's Classroom Behavior Inventory (CBI). CBI explores teacher perception of the child's behavior in the area of extraversion-introversion, task orientation-distractability, and hostility-considerateness. The total group of 87…

Parental Educational Involvement Conceived as the Arrangement of Contingency Operations

ERIC Educational Resources Information Center

Mellon, Robert C.; Moutavelis, Adrianos G.

2009-01-01

This study explored the utility of a conception of parental educational involvement as the arrangement of contingency operations that normatively change: the frequency of children's school-related behaviour, the reinforcing potency of stimuli produced by studying, and children's tendencies to request parental intervention. A child-report measure…

75 FR 54628 - Science Advisory Board Staff Office; Notification of a Public Teleconference of the Science...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-08

... a Public Teleconference of the Science Advisory Board; Polycyclic Aromatic Hydrocarbon (PAH... Hydrocarbon (PAH) Mixtures Review Panel to discuss its draft report on EPA's Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures. DATES: The SAB PAH Mixtures...

40 CFR 79.68 - Salmonella typhimurium reverse mutation assay.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Potency of Extracts of Diesel and Related Environmental Emissions: Study Design, Sample Generation... the present time, TA1535, TA1537, TA98, and TA100 are designated as tester strains. The fifth strain... this study shall be in accordance with good laboratory practice provisions under § 79.60. (1) Direct...

40 CFR 79.68 - Salmonella typhimurium reverse mutation assay.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Potency of Extracts of Diesel and Related Environmental Emissions: Study Design, Sample Generation... the present time, TA1535, TA1537, TA98, and TA100 are designated as tester strains. The fifth strain... this study shall be in accordance with good laboratory practice provisions under § 79.60. (1) Direct...

40 CFR 79.68 - Salmonella typhimurium reverse mutation assay.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Potency of Extracts of Diesel and Related Environmental Emissions: Study Design, Sample Generation... the present time, TA1535, TA1537, TA98, and TA100 are designated as tester strains. The fifth strain... this study shall be in accordance with good laboratory practice provisions under § 79.60. (1) Direct...

40 CFR 79.68 - Salmonella typhimurium reverse mutation assay.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Potency of Extracts of Diesel and Related Environmental Emissions: Study Design, Sample Generation... the present time, TA1535, TA1537, TA98, and TA100 are designated as tester strains. The fifth strain... this study shall be in accordance with good laboratory practice provisions under § 79.60. (1) Direct...

40 CFR 79.68 - Salmonella typhimurium reverse mutation assay.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Potency of Extracts of Diesel and Related Environmental Emissions: Study Design, Sample Generation... the present time, TA1535, TA1537, TA98, and TA100 are designated as tester strains. The fifth strain... this study shall be in accordance with good laboratory practice provisions under § 79.60. (1) Direct...

Postnatal effects of dipentyl phthalate on male reproductive development

EPA Science Inventory

We conducted several in utero, ex vivo and in vitro studies to characterize the relative potencies of a series of phthalates on fetal rat testis testosterone production and gene expression. Dipentyl phthalate (DPeP) was the most potent of the active chemicals in its effect on fet...

Estimated Reduction in Cancer Risk due to PAH Exposures If Source Control Measures during the 2008 Beijing Olympics Were Sustained

PubMed Central

Jia, Yuling; Stone, Dave; Wang, Wentao; Schrlau, Jill; Tao, Shu; Massey Simonich, Staci L.

2011-01-01

Background The 2008 Beijing Olympic Games provided a unique case study to investigate the effect of source control measures on the reduction in air pollution, and associated inhalation cancer risk, in a Chinese megacity. Objectives We measured 17 carcinogenic polycyclic aromatic hydrocarbons (PAHs) and estimated the lifetime excess inhalation cancer risk during different periods of the Beijing Olympic Games, to assess the effectiveness of source control measures in reducing PAH-induced inhalation cancer risks. Methods PAH concentrations were measured in samples of particulate matter ≤ 2.5 μm in aerodynamic diameter (PM2.5) collected during the Beijing Olympic Games, and the associated inhalation cancer risks were estimated using a point-estimate approach based on relative potency factors. Results We estimated the number of lifetime excess cancer cases due to exposure to the 17 carcinogenic PAHs [12 priority pollutant PAHs and five high-molecular-weight (302 Da) PAHs (MW 302 PAHs)] to range from 6.5 to 518 per million people for the source control period concentrations and from 12.2 to 964 per million people for the nonsource control period concentrations. This would correspond to a 46% reduction in estimated inhalation cancer risk due to source control measures, if these measures were sustained over time. Benzo[b]fluoranthene, dibenz[a,h]anthracene, benzo[a]pyrene, and dibenzo[a,l]pyrene were the most carcinogenic PAH species evaluated. Total excess inhalation cancer risk would be underestimated by 23% if we did not include the five MW 302 PAHs in the risk calculation. Conclusions Source control measures, such as those imposed during the 2008 Beijing Olympics, can significantly reduce the inhalation cancer risk associated with PAH exposure in Chinese megacities similar to Beijing. MW 302 PAHs are a significant contributor to the estimated overall inhalation cancer risk. PMID:21632310

The 2005 World Health Organization Re-evaluation of Human and Mammalian Toxic Equivalency Factors for Dioxins and Dioxin-like Compounds

PubMed Central

van den Berg, Martin; Birnbaum, Linda S.; Denison, Michael; De Vito, Mike; Farland, William; Feeley, Mark; Fiedler, Heidelore; Hakansson, Helen; Hanberg, Annika; Haws, Laurie; Rose, Martin; Safe, Stephen; Schrenk, Dieter; Tohyama, Chiharu; Tritscher, Angelika; Tuomisto, Jouko; Tysklind, Mats; Walker, Nigel; Peterson, Richard E.

2007-01-01

In June 2005 a WHO-IPCS expert meeting was held in Geneva during which the toxic equivalency factors (TEFs) for dioxin like compounds, including some polychlorinated biphenyls (PCBs), were re-evaluated. For this re-evaluation process the refined TEF database recently published by Haws and coworkers (Toxicol. Sci. 2006, 89:4-30) was used as a starting point. Decisions about a TEF value were made based on a combination of unweighted relative effect potency (REP) distributions from this database, expert judgement and point estimates. Previous TEFs were assigned in increments of 0.01, 0.05, 0.1, etc., but for this re-evaluation it was decided to use half order of magnitude increments on a logarithmic scale of 0.03, 0.1, 0.3 etc. Changes were decided by the expert panel for 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) (TEF=0.3), 1,2,3,7,8-pentachlorodibenzofuran (PeCDF) (TEF=0.03), octachlorodibenzo-p-dioxin (OCDD) and octachlorodibenzofuran (OCDF) (TEFs=0.0003), 3,4,4’,5-tetrachlorbiphenyl (PCB 81) (TEF=0.0003), 3,3’,4,4’,5,5’-hexachlorobiphenyl (PCB 169) (TEF=0.03) and a single TEF value (0.00003) for all relevant mono-ortho substituted PCBs. Additivity, an important prerequisite of the TEF concept was again confirmed by results from recent in vivo mixture studies. Some experimental evidence shows that nondioxin-like aryl hydrocarbon receptor (AhR) agonists/antagonists are able to impact the overall toxic potency of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds and this needs to be investigated further. Certain individual and groups of compounds were identified for possible future inclusion in the TEF concept, including 3,4,4’-TCB (PCB 37), polybrominated dibenzo-p-dioxins (PBDDs) and dibenzofurans (PBDFs), mixed polyhalogenated dibenzo-p-dioxins and dibenzofurans, polyhalogenated naphthalenes and polybrominated biphenyls (PBBs). Concern was expressed about direct application of the TEF/TEQ approach to abiotic matrices such as soil, sediment etc., for direct application in human risk assessment. This is problematic, as the present TEF scheme and TEQ methodology is primarily intended for estimating exposure and risks via oral ingestion (e.g., by dietary intake). A number of future approaches to determine alternative or additional TEFs were also identified. These included the use of a probabilistic methodology to determine TEFs that better describe the associated levels of uncertainty and ‘systemic’ TEFs for blood and adipose tissue and total toxic equivalency (TEQ) for body burden. PMID:16829543

The prognostic reliability of intracranial pressure monitoring and MRI data in severe traumatic brain injury.

PubMed

Woischneck, Dieter; Kapapa, Thomas

2017-02-01

The predictive quality of intracranial pressure (ICP) monitoring has for many years been a matter of debate. We correlate ICP data comparing MRI data with the outcome after severe traumatic brain injury to evaluate their prognostic potency. This study compares the results of ICP monitoring, MRI, coma duration and outcome according to Glasgow Outcome Scale obtained in 32 patients having suffered severe TBI. Level of significance was set to p≤0.05 in statistical tests. The MRI results were closely correlated with coma duration and Glasgow Outcome Scale, but the ICP measurements were not. With the exception of severe, bipontine lesions, there is no other region of the brain in which increased evidence of traumatogenic lesions emerges as the intracranial pressure rises. Just bipontine lesions that proof to be infaust correlate with elevated ICP values. ICP monitoring does not allow individual prognostic conclusions to be made. Implantation of an intracranial pressure sensor alone for making a prognostic estimate is not advisable. The use of intracranial pressure measurements in the retrospective appraisal of disease progress is highly problematic. However, MRI diagnostic in patients with severe TBI improves prognostic potency of clinical parameters. Copyright © 2016 Elsevier Inc. All rights reserved.

Predicting the toxicity of metal mixtures

USGS Publications Warehouse

Balistrieri, Laurie S.; Mebane, Christopher A.

2013-01-01

The toxicity of single and multiple metal (Cd, Cu, Pb, and Zn) solutions to trout is predicted using an approach that combines calculations of: (1) solution speciation; (2) competition and accumulation of cations (H, Ca, Mg, Na, Cd, Cu, Pb, and Zn) on low abundance, high affinity and high abundance, low affinity biotic ligand sites; (3) a toxicity function that accounts for accumulation and potency of individual toxicants; and (4) biological response. The approach is evaluated by examining water composition from single metal toxicity tests of trout at 50% mortality, results of theoretical calculations of metal accumulation on fish gills and associated mortality for single, binary, ternary, and quaternary metal solutions, and predictions for a field site impacted by acid rock drainage. These evaluations indicate that toxicity of metal mixtures depends on the relative affinity and potency of toxicants for a given aquatic organism, suites of metals in the mixture, dissolved metal concentrations and ratios, and background solution composition (temperature, pH, and concentrations of major ions and dissolved organic carbon). A composite function that incorporates solution composition, affinity and competition of cations for two types of biotic ligand sites, and potencies of hydrogen and individual metals is proposed as a tool to evaluate potential toxicity of environmental solutions to trout.

The higher barrier of darunavir and tipranavir resistance for HIV-1 protease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yong; Liu, Zhigang; Brunzelle, Joseph S.

2011-11-17

Darunavir and tipranavir are two inhibitors that are active against multi-drug resistant (MDR) HIV-1 protease variants. In this study, the invitro inhibitory efficacy was tested against a MDR HIV-1 protease variant, MDR 769 82T, containing the drug resistance mutations of 46L/54V/82T/84V/90M. Crystallographic and enzymatic studies were performed to examine the mechanism of resistance and the relative maintenance of potency. The key findings are as follows: (i) The MDR protease exhibits decreased susceptibility to all nine HIV-1 protease inhibitors approved by the US Food and Drug Administration (FDA), among which darunavir and tipranavir are the most potent; (ii) the threonine 82more » mutation on the protease greatly enhances drug resistance by altering the hydrophobicity of the binding pocket; (iii) darunavir or tipranavir binding facilitates closure of the wide-open flaps of the MDR protease; and (iv) the remaining potency of tipranavir may be preserved by stabilizing the flaps in the inhibitor-protease complex while darunavir maintains its potency by preserving protein main chain hydrogen bonds with the flexible P2 group. These results could provide new insights into drug design strategies to overcome multi-drug resistance of HIV-1 protease variants.« less

Comparative in vitro study of the antimicrobial activities of different commercial antibiotic products of vancomycin

PubMed Central

2011-01-01

Background One of the most critical problems about antimicrobial therapy is the increasing resistance to antibiotics. Previous studies have shown that there is a direct relation between erroneous prescription, dosage, route, duration of the therapy and the antibiotics resistance. Other important point is the uncertainty about the quality of the prescribed medicines. Some physicians believe that generic drugs are not as effective as innovator ones, so it is very important to have evidence that shows that all commercialized drugs are suitable for therapeutic use. Methods Microbial assays were used to establish the potency, the Minimal Inhibitory Concentrations (MICs), the Minimal Bactericidal Concentration (MBCs), the critical concentrations, and the production of spontaneous mutants that are resistant to vancomycin. Results The microbial assay was validated in order to determine the Vancomycin potency of the tasted samples. All the products showed that have potency values between 90 - 115% (USP requirement). The products behave similarly because the MICs, The MBCs, the critical concentrations, the critical concentrations ratios between standard and samples, and the production of spontaneous mutants don't have significant differences. Conclusions All products analyzed by microbiological tests, show that both trademarks and generics do not have statistical variability and the answer of antimicrobial activity Show also that they are pharmaceutical equivalents. PMID:21777438

Comparative in vitro study of the antimicrobial activities of different commercial antibiotic products of vancomycin.

PubMed

Diaz, Jorge A; Silva, Edelberto; Arias, Maria J; Garzón, María

2011-07-21

One of the most critical problems about antimicrobial therapy is the increasing resistance to antibiotics. Previous studies have shown that there is a direct relation between erroneous prescription, dosage, route, duration of the therapy and the antibiotics resistance. Other important point is the uncertainty about the quality of the prescribed medicines. Some physicians believe that generic drugs are not as effective as innovator ones, so it is very important to have evidence that shows that all commercialized drugs are suitable for therapeutic use. Microbial assays were used to establish the potency, the Minimal Inhibitory Concentrations (MICs), the Minimal Bactericidal Concentration (MBCs), the critical concentrations, and the production of spontaneous mutants that are resistant to vancomycin. The microbial assay was validated in order to determine the Vancomycin potency of the tasted samples. All the products showed that have potency values between 90 - 115% (USP requirement). The products behave similarly because the MICs, The MBCs, the critical concentrations, the critical concentrations ratios between standard and samples, and the production of spontaneous mutants don't have significant differences. All products analyzed by microbiological tests, show that both trademarks and generics do not have statistical variability and the answer of antimicrobial activity Show also that they are pharmaceutical equivalents.

Comparative stability of repackaged metoprolol tartrate tablets.

PubMed

Yang, Yongsheng; Gupta, Abhay; Carlin, Alan S; Faustino, Patrick J; Lyon, Robbe C; Ellison, Christopher D; Rothman, Barry; Khan, Mansoor A

2010-01-29

The stability of metoprolol tartrate tablets packaged in original high density polyethylene containers and repackaged in USP Class A unit-dose blister packs was investigated. Studies were conducted at 25 degrees C/60% relative humidity (RH) for 52 weeks and at 40 degrees C/75% RH for 13 weeks. The potency, dissolution, water content, loss on drying and hardness of the drug products were analyzed. Results indicated no differences in the stability between the tablets in both packages stored under 25 degrees C/60% RH. No difference in potency was found in both packages under either condition. However, a significant weight increase due to moisture uptake was observed for the repackaged tablets stored under 40 degrees C/75% RH. The weight increase was accompanied by a decrease in tablet hardness (6.5-0 kp) and a increase in dissolution rate (51-92%) in 5 min. Near-infrared (NIR) chemical imaging also monitored moisture uptake of the tablet non-invasively through the package. The observed changes in product stability may adversely affect the products bioavailability profile, even though the potency of the active drug remained within USP specification range of 90-110%. Study results suggest product quality can be negatively impacted even when using USP Class A repackaging materials. Published by Elsevier B.V.

Evaluation of the use of various rat strains for immunogenic potency tests of Sabin-derived inactivated polio vaccines.

PubMed

Someya, Yuichi; Ami, Yasushi; Takai-Todaka, Reiko; Fujimoto, Akira; Haga, Kei; Murakami, Kosuke; Fujii, Yoshiki; Shirato, Haruko; Oka, Tomoichiro; Shimoike, Takashi; Katayama, Kazuhiko; Wakita, Takaji

2018-03-01

Slc:Wistar rats have been the only strain used in Japan for purpose of evaluating a national reference vaccine for the Sabin-derived inactivated polio vaccine (sIPV) and the immunogenicity of sIPV-containing products. However, following the discovery that the Slc:Wistar strain was genetically related to the Fischer 344 strain, other "real" Wistar strains, such as Crlj:WI, that are available worldwide were tested in terms of their usefulness in evaluating the immunogenicity of the past and current lots of a national reference vaccine. The response of the Crlj:WI rats against the serotype 1 of sIPV was comparable to that of the Slc:Wistar rats, while the Crlj:WI rats exhibited a higher level of response against the serotypes 2 and 3. The immunogenic potency units of a national reference vaccine determined using the Slc:Wistar rats were reproduced on tests using the Crlj:WI rats. These results indicate that a titer of the neutralizing antibody obtained in response to a given dose of sIPV cannot be directly compared between these two rat strains, but that, more importantly, the potency units are almost equivalent for the two rat strains. Copyright © 2018 International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

Synergistic effects between analogs of DNA and RNA improve the potency of siRNA-mediated gene silencing

PubMed Central

Deleavey, Glen F.; Watts, Jonathan K.; Alain, Tommy; Robert, Francis; Kalota, Anna; Aishwarya, Veenu; Pelletier, Jerry; Gewirtz, Alan M.; Sonenberg, Nahum; Damha, Masad J.

2010-01-01

We report that combining a DNA analog (2′F-ANA) with rigid RNA analogs [2′F-RNA and/or locked nucleic acid (LNA)] in siRNA duplexes can produce gene silencing agents with enhanced potency. The favored conformations of these two analogs are different, and combining them in a 1–1 pattern led to reduced affinity, whereas alternating short continuous regions of individual modifications increased affinity relative to an RNA:RNA duplex. Thus, the binding affinity at key regions of the siRNA duplex could be tuned by changing the pattern of incorporation of DNA-like and RNA-like nucleotides. These heavily or fully modified duplexes are active against a range of mRNA targets. Effective patterns of modification were chosen based on screens using two sequences targeting firefly luciferase. We then applied the most effective duplex designs to the knockdown of the eIF4E binding proteins 4E-BP1 and 4E-BP2. We identified modified duplexes with potency comparable to native siRNA. Modified duplexes showed dramatically enhanced stability to serum nucleases, and were characterized by circular dichroism and thermal denaturation studies. Chemical modification significantly reduced the immunostimulatory properties of these siRNAs in human peripheral blood mononuclear cells. PMID:20413581

Potency and selectivity of carprofen enantiomers for inhibition of bovine cyclooxygenase in whole blood assays.

PubMed

Brentnall, Claire; Cheng, Zhangrui; McKellar, Quintin A; Lees, Peter

2012-12-01

Whole blood in vitro assays were used to determine the potency and selectivity of carprofen enantiomers for inhibition of the isoforms of cyclooxygenase (COX), COX-1 and COX-2, in the calf. S(+)-carprofen possessed preferential activity for COX-2 inhibition but, because the slopes of inhibition curves differed, the COX-1:COX-2 inhibition ratio decreased from 9.04:1 for inhibitory concentration (IC)10 to 1.84:1 for IC95. R(-) carprofen inhibited COX-2 preferentially only for low inhibition of the COX isoforms (IC10 COX-1:COX-2=6.63:1), whereas inhibition was preferential for COX-1 for a high level of inhibition (IC95 COX-1:COX-2=0.20:1). S(+) carprofen was the more potent inhibitor of COX isoforms; potency ratios S(+):R(-) carprofen were 11.6:1 for IC10 and 218:1 for IC90. Based on serum concentrations of carprofen enantiomers obtained after administration of a therapeutic dose of 1.4 mg/kg to calves subcutaneously, S(+)-carprofen concentrations exceeded the in vitro IC80 COX-2 value for 32 h and the IC20 for COX-1 for 33 h. The findings are discussed in relation to efficacy and safety of carprofen in calves. Copyright © 2012 Elsevier Ltd. All rights reserved.

Single-Chain Fv-Based Anti-HIV Proteins: Potential and Limitations

PubMed Central

West, Anthony P.; Galimidi, Rachel P.; Gnanapragasam, Priyanthi N. P.

2012-01-01

The existence of very potent, broadly neutralizing antibodies against human immunodeficiency virus type 1 (HIV-1) offers the potential for prophylaxis against HIV-1 infection by passive immunization or gene therapy. Both routes permit the delivery of modified forms of IgGs. Smaller reagents are favored when considering ease of tissue penetration and the limited capacities of gene therapy vectors. Immunoadhesin (single-chain fragment variable [scFv]-Fc) forms of IgGs are one class of relatively small reagent that has been explored for delivery by adeno-associated virus. Here we investigated the neutralization potencies of immunoadhesins compared to those of their parent IgGs. For the antibodies VRC01, PG9, and PG16, the immunoadhesins showed modestly reduced potencies, likely reflecting reduced affinities compared to those of the parent IgG, and the VRC01 immunoadhesin formed dimers and multimers with reduced neutralization potencies. Although scFv forms of neutralizing antibodies may exhibit affinity reductions, they provide a means of building reagents with multiple activities. Attachment of the VRC01 scFv to PG16 IgG yielded a bispecific reagent whose neutralization activity combined activities from both parent antibodies. Although the neutralization activity due to each component was partially reduced, the combined reagent is attractive since fewer strains escaped neutralization. PMID:22013046

BoNT/AB hybrid maintains similar duration of paresis as BoNT/A wild-type in murine running wheel assay.

PubMed

Kutschenko, Anna; Reinert, Marie-Christine; Krez, Nadja; Liebetanz, David; Rummel, Andreas

2017-03-01

The highly potent Botulinum neurotoxins (BoNT) are successful drugs to treat neuromuscular disorders. Efforts are being made to further reduce the injected BoNT dose and to lengthen the interval between treatments. Detailed knowledge of the BoNT structure-activity relationship (SAR) allows combining the best features of the different BoNT serotypes. Of all seven BoNT serotypes A-G, BoNT/A displays the highest potency despite low neuronal binding affinity, while BoNT/B exhibits much higher affinity. Recently, a new BoNT/AB hybrid (AABB) was constructed comprising the catalytic and translocation domain of BoNT/A and the 50kDa cell binding domain of BoNT/B. Here, we compared BoNT/A wild-type (AAAA) and AABB with regard to ex vivo potency and in vivo potency, efficacy and duration of action using the mouse phrenic nerve hemidiaphragm assay and the murine running wheel assay, respectively. The ex vivo potency of AABB was found to be 8.4-fold higher than that of AAAA. For the latter, two and 5 pg each of AAAA and AABB, respectively, were bilaterally injected into the calf muscles and mouse running wheel performance was automatically monitored during the following weeks to determine potency, efficacy and duration. Mice displayed a dose-dependent impairment of running performance. AABB showed potency, efficacy and duration equal to AAAA demonstrating successful exchange of the cell binding domain. AABB might combine the higher potency and longer duration of BoNT/A with the target specificity for the autonomic nervous system of BoNT/B. AABB might therefore constitute an improved treatment option for acetylcholine-mediated autonomic disorders such as hypersalivation or hyperhidrosis. Copyright © 2016 Elsevier B.V. All rights reserved.

Development and validation of a rapid, aldehyde dehydrogenase bright-based cord blood potency assay.

PubMed

Shoulars, Kevin; Noldner, Pamela; Troy, Jesse D; Cheatham, Lynn; Parrish, Amanda; Page, Kristin; Gentry, Tracy; Balber, Andrew E; Kurtzberg, Joanne

2016-05-12

Banked, unrelated umbilical cord blood provides access to hematopoietic stem cell transplantation for patients lacking matched bone marrow donors, yet 10% to 15% of patients experience graft failure or delayed engraftment. This may be due, at least in part, to inadequate potency of the selected cord blood unit (CBU). CBU potency is typically assessed before cryopreservation, neglecting changes in potency occurring during freezing and thawing. Colony-forming units (CFUs) have been previously shown to predict CBU potency, defined as the ability to engraft in patients by day 42 posttransplant. However, the CFU assay is difficult to standardize and requires 2 weeks to perform. Consequently, we developed a rapid multiparameter flow cytometric CBU potency assay that enumerates cells expressing high levels of the enzyme aldehyde dehydrogenase (ALDH bright [ALDH(br)]), along with viable CD45(+) or CD34(+) cell content. These measurements are made on a segment that was attached to a cryopreserved CBU. We validated the assay with prespecified criteria testing accuracy, specificity, repeatability, intermediate precision, and linearity. We then prospectively examined the correlations among ALDH(br), CD34(+), and CFU content of 3908 segments over a 5-year period. ALDH(br) (r = 0.78; 95% confidence interval [CI], 0.76-0.79), but not CD34(+) (r = 0.25; 95% CI, 0.22-0.28), was strongly correlated with CFU content as well as ALDH(br) content of the CBU. These results suggest that the ALDH(br) segment assay (based on unit characteristics measured before release) is a reliable assessment of potency that allows rapid selection and release of CBUs from the cord blood bank to the transplant center for transplantation. © 2016 by The American Society of Hematology.

Development and validation of a rapid, aldehyde dehydrogenase bright–based cord blood potency assay

PubMed Central

Noldner, Pamela; Troy, Jesse D.; Cheatham, Lynn; Parrish, Amanda; Page, Kristin; Gentry, Tracy; Balber, Andrew E.; Kurtzberg, Joanne

2016-01-01

Banked, unrelated umbilical cord blood provides access to hematopoietic stem cell transplantation for patients lacking matched bone marrow donors, yet 10% to 15% of patients experience graft failure or delayed engraftment. This may be due, at least in part, to inadequate potency of the selected cord blood unit (CBU). CBU potency is typically assessed before cryopreservation, neglecting changes in potency occurring during freezing and thawing. Colony-forming units (CFUs) have been previously shown to predict CBU potency, defined as the ability to engraft in patients by day 42 posttransplant. However, the CFU assay is difficult to standardize and requires 2 weeks to perform. Consequently, we developed a rapid multiparameter flow cytometric CBU potency assay that enumerates cells expressing high levels of the enzyme aldehyde dehydrogenase (ALDH bright [ALDHbr]), along with viable CD45+ or CD34+ cell content. These measurements are made on a segment that was attached to a cryopreserved CBU. We validated the assay with prespecified criteria testing accuracy, specificity, repeatability, intermediate precision, and linearity. We then prospectively examined the correlations among ALDHbr, CD34+, and CFU content of 3908 segments over a 5-year period. ALDHbr (r = 0.78; 95% confidence interval [CI], 0.76-0.79), but not CD34+ (r = 0.25; 95% CI, 0.22-0.28), was strongly correlated with CFU content as well as ALDHbr content of the CBU. These results suggest that the ALDHbr segment assay (based on unit characteristics measured before release) is a reliable assessment of potency that allows rapid selection and release of CBUs from the cord blood bank to the transplant center for transplantation. PMID:26968535

Comparison of the interleukin-1β-inducing potency of allergenic spores from higher fungi (Basidiomycetes) in a cryopreserved human whole blood system

PubMed Central

Rivera-Mariani, Félix E.; Vysyaraju, Kranthi; Negherbon, Jesse; Levetin, Estelle; Horner, W. Elliot; Hartung, Thomas; Breysse, Patrick N.

2014-01-01

Background Spores from basidiomycete fungi (basidiospores) are highly prevalent in the atmosphere of urban and rural settings. Studies have confirmed their potential to affect human health as allergens. Less is known about their potential to serve as stimuli of the innate immune system and induce pro-inflammatory reactions. Methods In this study, we evaluated the pro-inflammatory potential of spores from 11 allergenic gilled (Pleurotus ostreatus, Oudemansiella radicata, Armillaria tabescens, Coprinus micaceus, Pluteus cervinus, Chlorophyllum molybdites) and non-gilled (Pisolithus arhizus, Merulius tremullosus, Calvatia cyathiformis, Lycoperdon pyriforme, Boletus bicolor) basidiomycetes fungi based on their potency to induce the release of the pro-inflammatory cytokine interleukin (IL)-1β in a cryopreserved human whole blood system. In addition, the role of morphological features of the spores (surface area, shape, and pigmentation) were examined for their role in the spores’ interleukin (IL)-1β-including potency. Peripheral blood from healthy volunteers was collected, pooled, and cryopreserved. After stimulating the cryopreserved pooled blood with 106 to 103 basidiospores/ml, the concentration of IL-1β in culture supernatants was determined with ELISA. Results Basidiospores manifested concentration-dependent IL-1β-inducing potency, which was more noteworthy among basidiospores from gilled basidiomycetes. At higher concentrations of basidiospores, the IL-1β-inducing potency was able to be differentiated in the cryopreserved human whole blood system. Morphological features did not correlate with the IL-1β-inducing potency of the basidiospores, suggesting that non-morphological properties modulate the IL-1β-inducing potency. Conclusion Our data provides evidence of the pro-inflammatory potential of basidiospores, and the utility of cryopreserved human whole blood as a human-based in-vitro system to study the immune reactivity of allergenic basidiospores. PMID:24356469

Cannabinoid receptor-dependent and -independent anti-proliferative effects of omega-3 ethanolamides in androgen receptor-positive and -negative prostate cancer cell lines

PubMed Central

Brown, Iain; Cascio, Maria G.; Wahle, Klaus W.J.; Smoum, Reem; Mechoulam, Raphael; Ross, Ruth A.; Pertwee, Roger G.; Heys, Steven D.

2010-01-01

The omega-3 fatty acid ethanolamides, docosahexaenoyl ethanolamide (DHEA) and eicosapentaenoyl ethanolamide (EPEA), displayed greater anti-proliferative potency than their parent omega-3 fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), in LNCaP and PC3 prostate cancer cells. DHEA and EPEA activated cannabinoid CB1 and CB2 receptors in vitro with significant potency, suggesting that they are endocannabinoids. Both LNCaP and PC3 cells expressed CB1 and CB2 receptors, and the CB1- and CB2-selective antagonists, AM281 and AM630, administered separately or together, reduced the anti-proliferative potencies of EPEA and EPA but not of DHEA or DHA in PC3 cells and of EPA but not of EPEA, DHEA or DHA in LNCaP cells. Even so, EPEA and EPA may not have inhibited PC3 or LNCaP cell proliferation via cannabinoid receptors since the anti-proliferative potency of EPEA was well below the potency it displayed as a CB1 or CB2 receptor agonist. Indeed, these receptors may mediate a protective effect because the anti-proliferative potency of DHEA in LNCaP and PC3 cells was increased by separate or combined administration of AM281 and AM630. The anandamide-metabolizing enzyme, fatty acid amide hydrolase (FAAH), was highly expressed in LNCaP but not PC3 cells. Evidence was obtained that FAAH metabolizes EPEA and DHEA and that the anti-proliferative potencies of these ethanolamides in LNCaP cells can be enhanced by inhibiting this enzyme. Our findings suggest that the expression of cannabinoid receptors and of FAAH in some tumour cells could well influence the effectiveness of DHA and EPA or their ethanolamide derivatives as anticancer agents. PMID:20660502

[Toxicity study of cefmatilen hydrochloride hydrate (S-1090) (4)--One- and three-month repeated oral dose toxicity studies in dogs].

PubMed

Yahara, I; Yamagata, H; Ueno, M; Inoue, S; Sato, K; Nishimura, K; Miyauchi, H; Hirata, M; Muraoka, Y; Kimura, Y; Kitamura, T; Kato, I

2001-05-01

One- or three-month repeated oral dose toxicity studies of Cefmatilen hydrochloride hydrate (S-1090) were conducted in beagle dogs. Doses were set at 25, 100 and 400 mg potency/kg/day in both studies. In both studies, no deaths occurred, and reddish-brown feces (due to chelated products of S-1090 and its decomposition products with Fe3+ in the diet) were observed in all treated groups. A transient excretion of reddish urine was observed in the 400 mg potency/kg group and a slight increase in plasma irons was also observed in the 100 and 400 mg potency/kg groups of both studies. However, as no changes suggesting anemia or hepatic injury were noted in these groups, the change of plasma irons was considered to have no toxicological significance. Plasma S-1090 concentrations increased in a manner less than dose-proportional in both studies. In the one-month toxicity study, no toxicologically significant changes, including the above findings, were noted, so the NOAEL was assessed to be 400 mg potency/kg/day. In the three-month toxicity study, urinalysis in the 400 mg potency/kg group revealed a positive reaction to occult blood and erythrocytes in sediments. In the pathological examinations, submucosal edema, hemorrhage, inflammatory cell infiltration and occasionally focal mucosal thickening were observed in the urinary bladder of the 400 mg potency/kg group. The cystisis was considered to result from chronic stimulation with the metabolite(s) of S-1090 in urine, and the reversibility was demonstrable upon one-month drug withdrawal. From these results, the NOAEL of S-1090 in the three-month toxicity study was assessed to be 100 mg potency/kg/day.

Topical corticosteroids in the treatment of acute sunburn: a randomized, double-blind clinical trial.

PubMed

Faurschou, Annesofie; Wulf, Hans C

2008-05-01

To examine the effect of topical corticosteroid treatment on acute sunburn. Randomized, double-blind clinical trial. University dermatology department. Twenty healthy volunteers with Fitzpatrick skin types I (highly sensitive, always burns easily, tans minimally) through III (sun-sensitive skin, sometimes burns, slowly tans to light brown). Seven 34-cm(2) areas were marked on the upper aspect of the back of each participant. An untreated area was tested to determine UV sensitivity. Two areas were treated with excess amounts (2 mg/cm(2)) of either a moderate-potency corticosteroid or a high-potency corticosteroid 30 minutes before UV-B exposure as controls. Six or 23 hours after exposure to radiation, the remaining areas were treated with the 2 corticosteroid preparations. The sunburn improvement factor (SIF) was determined by the following equation: SIF = MED (minimal erythema dose) on treated skin/MED on nontreated skin. An SIF greater than 1 indicated an effect of topical corticosteroids in sunburn relief. The SIFs in the areas treated with either topical corticosteroid 30 minutes before UV-B exposure or high-potency corticosteroid 6 hours after UV-B exposure were significantly different from SIFs in areas that received no treatment (SIF 1.1-1.7; P < .05). Only the median SIF of 1.7 in the areas treated with high-potency corticosteroid 30 minutes before UV-B exposure was clinically relevant. The areas treated 23 hours after UV-B exposure and the areas treated with a moderate-potency corticosteroid 6 hours after UV-B exposure showed no significant reduction in redness. Treatment with topical moderate-potency or high-potency corticosteroids does not provide a clinically useful decrease in the acute sunburn reaction when applied 6 or 23 hours after UV exposure.

Potency assay design for adjuvanted recombinant proteins as malaria vaccines.

PubMed

Giersing, Birgitte K; Dubovsky, Filip; Saul, Allan; Denamur, Francoise; Minor, Philip; Meade, Bruce

2006-05-15

Many licensed vaccines are composed of live, attenuated or inactivated whole-cell microorganisms, or they comprise purified components from whole-cell extracts or culture supernatants. For some diseases, pathology is fairly well understood, and there may be known correlates of protection that provide obvious parameters for assessment of vaccine potency. However, this is not always the case, and some effective vaccines are routinely used even though the mechanisms or correlates of protection are unknown. Some more modern vaccine approaches employ purified recombinant proteins, based on molecules that appear on the surface of the pathogen. This is one of the strategies that has been adopted in the quest to develop a malaria vaccine. Use of these parasite antigens as vaccine candidates is supported by substantial epidemiological data, and some have demonstrated the ability to elicit protective responses in animal models of malaria infection. However, there is as yet no immunological correlate of protection and no functional assays or animal models that have demonstrated the ability to predict efficacy in humans. There is little precedence for the most appropriate and practical method for assessing potency of vaccines based on these recombinant molecules for malaria vaccines. This is likely because the majority of malaria vaccine candidates have only recently entered clinical evaluation. The PATH Malaria Vaccine Initiative (MVI) convened a panel with expertise in potency assay design from industry, governmental institutions, and regulatory bodies to discuss and review the rationale, available methods, and best approaches for assessing the potency of recombinant proteins, specifically for their use as malarial vaccines. The aim of this meeting was to produce a discussion document on the practical potency assessment of recombinant protein malaria vaccines, focusing on early phase potency assay development.

Studying the reducing potencies of antioxidants with the electrochemistry inherently present in electrospray ionization-mass spectrometry.

PubMed

Plattner, Sabine; Erb, Robert; Chervet, Jean-Pierre; Oberacher, Herbert

2014-01-01

In this proof-of-principle study, the applicability of electrospray ionization-mass spectrometry (ESI-MS) to characterize the reducing potencies of natural antioxidants is demonstrated. The ESI source represents a controlled-current electrochemical cell. The interfacial potential at the emitter electrode will be at or near the electrochemical potential of those reactions that sufficiently supply all the required current for the ESI circuit. Indicator molecules prone to oxidation in ESI such as amodiaquine were used to visualize the impact of reducing compounds on the interfacial potential. The extent of inhibition of the oxidation of the indicator molecule was found to be dependent on the kind and amount of antioxidant added. Concentration-inhibition curves were constructed and used to compare reducing potencies and to rank antioxidants. This ranking was found to be dependent on the electrode material-indicator molecule combination applied. For fast and automated characterization of the reducing potencies of electrochemically active molecules, a flow-injection system was combined with ESI-MS. Liquid chromatography was used to process complex biological samples, such as red and white wine. Due to their high content of different polyphenols, red wine fractions were found to exhibit higher reducing potencies than the corresponding white wine fractions. Furthermore, for 14 important natural antioxidants, the results obtained with the controlled-current EC-ESI-MS assay were compared to those obtained with chemical antioxidant assays. Irrespectively of the kind of assay used to test the reducing potency, gallic acid, quercetin, and epicatechin were found to be potent reductants. Other antioxidants performed well in one particular assay only. This observation suggests that different kinds of redox and antioxidant chemistry were assessed with each of the assays applied. Therefore, several assays should be used to comprehensively study antioxidants and their reducing potencies.

Assessment of toxic potency of complex mixtures of PAHs from Lincoln Creek, Milwaukee, WI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Villeneuve, D.; Crunkilton, R.; DeVita, W.

1995-12-31

An assay of cytochrome P4501A catalytic activity in PLHC-1 fish hepatoma cells was used to evaluate the toxic potency of dialysates from triolein filled semipermeable polymeric membrane devices (SPMDS) exposed for variable durations and under various flow regimes to water from Lincoln Creek. Toxic potency was expressed as 2,3,7,8 tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQ) calculated from bioassay results. Dose-dependent responses in measured ethoxyresorufin-o-deethylase (EROD) activity of PLHC-1 cells exposed to SPMD dialysates were shown. Toxic potency of dialysates, expressed as bioassay derived TCDD equivalents, increased with duration of SPMD exposure in Lincoln Creek from 2.0 pg/uL for a 2 day exposure tomore » 19.5 pg/uL for a 30 day exposure. This corresponded to an increase in dialysate polycyclic aromatic hydrocarbon (PAH) concentration from 8.82 ug/g after a 2 day exposure to 24.14 ug/g after 30 days. Dialysates from SPMDs exposed to Lincoln Creek stormflow had higher toxic potencies and total PAH concentrations than those exposed to baseflow only, These results suggest that levels of PAH contamination, particularly those associated with stormflow, in Lincoln Creek have potential to accumulate in fish to levels significant enough to elicit a measurable biological response (cytochrome P4501 A induction) at a potency level approaching 0.08% that of TCDD.« less

Prenatal developmental toxicity testing of petroleum substances: Application of the mouse embryonic stem cell test (EST) to compare in vitro potencies with potencies observed in vivo.

PubMed

Kamelia, Lenny; Louisse, Jochem; de Haan, Laura; Rietjens, Ivonne M C M; Boogaard, Peter J

2017-10-01

Prenatal developmental toxicity (PDT) as observed with some petroleum substances (PS) has been associated with the presence of 3-7 ring polycyclic aromatic hydrocarbons (PAHs). In the present study, the applicability of ES-D3 cell differentiation assay of the EST to evaluate in vitro embryotoxicity potencies of PS and gas-to-liquid (GTL) products as compared to their in vivo potencies was investigated. DMSO-extracts of a range of PS, containing different amounts of PAHs, and GTL-products, which are devoid of PAHs, were tested in the ES-D3 cell proliferation and differentiation assays of the EST. The results show that PS inhibited the differentiation of ES-D3 cells into cardiomyocytes in a concentration-dependent manner at non-cytotoxic concentrations, and that their potency was proportional to their PAH content. In contrast, as expected, GTL-products did not inhibit ES-D3 cell viability or differentiation at all. The in vitro PDT potencies were compared to published in vivo PDT studies, and a good correlation was found between in vitro and in vivo results (R 2 =0.97). To conclude, our results support the hypothesis that PAHs are the primary inducers of the PDT in PS. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Cyclic Peptide-Polymer Nanotubes as Efficient and Highly Potent Drug Delivery Systems for Organometallic Anticancer Complexes.

PubMed

Larnaudie, Sophie C; Brendel, Johannes C; Romero-Canelón, Isolda; Sanchez-Cano, Carlos; Catrouillet, Sylvain; Sanchis, Joaquin; Coverdale, James P C; Song, Ji-Inn; Habtemariam, Abraha; Sadler, Peter J; Jolliffe, Katrina A; Perrier, Sébastien

2018-01-08

Functional drug carrier systems have potential for increasing solubility and potency of drugs while reducing side effects. Complex polymeric materials, particularly anisotropic structures, are especially attractive due to their long circulation times. Here, we have conjugated cyclic peptides to the biocompatible polymer poly(2-hydroxypropyl methacrylamide) (pHPMA). The resulting conjugates were functionalized with organoiridium anticancer complexes. Small angle neutron scattering and static light scattering confirmed their self-assembly and elongated cylindrical shape. Drug-loaded nanotubes exhibited more potent antiproliferative activity toward human cancer cells than either free drug or the drug-loaded polymers, while the nanotubes themselves were nontoxic. Cellular accumulation studies revealed that the increased potency of the conjugate appears to be related to a more efficient mode of action rather than a higher cellular accumulation of iridium.

Nitric Oxide Mediates Glutamate-Linked Enhancement of cGMP Levels in the Cerebellum

NASA Astrophysics Data System (ADS)

Bredt, David S.; Snyder, Solomon H.

1989-11-01

Nitric oxide, which mediates influences of numerous neurotransmitters and modulators on vascular smooth muscle and leukocytes, can be formed in the brain from arginine by an enzymatic activity that stoichiometrically generates citrulline. We show that glutamate and related amino acids, such as N-methyl-D-aspartate, markedly stimulate arginine-citrulline transformation in cerebellar slices stoichiometrically with enhancement of cGMP levels. Nω-monomethyl-L-arginine blocks the augmentation both of citrulline and cGMP with identical potencies. Arginine competitively reverses both effects of Nω-monomethyl-L-arginine with the same potencies. Hemoglobin, which complexes nitric oxide, prevents the stimulation by N-methyl-D-aspartate of cGMP levels, and superoxide dismutase, which elevates nitric oxide levels, increases cGMP formation. These data establish that nitric oxide mediates the stimulation by glutamate of cGMP formation.

The antipyretic effect of indomethacin.

PubMed Central

Clark, W G; Cumby, H R

1975-01-01

1. Several possible mechanisms of the antipyretic action of indomethacin administered cat. 2. Indomethacin did not decrease bacterial endotoxin-induced release of endogenous pyrogen in vivo. 3. Indomethacin (5-40 mug/kg) inhibited the pyrogenic effect of peripherally or centrally administered leucocytic progen. A dose of 10 mug/kg caused a parallel shift to the right of the log dose-response curve for I.V. leucocytic pyrogen and reduced the potency of the pyrogen at least 50%. 4. Incubation of leucocytic pyrogen with indomethacin did not alter its pyrogenic potency. 5. Indomethacin exerted only a slight non-dose-related hypothermic effect in afebrile animals. 6. Indomethacin (up to 1 mg/kg) did not diminish the hyperthermic response to intraventricular administration of prostaglandin E1. 7. This pattern of activity indicates that indomethacin acts centrally to inhibit an effect of leucocytic pyrogen. PMID:1151840

Motivational Hierarchy in the Chinese Brain: Primacy of the Individual Self, Relational Self, or Collective Self?

PubMed

Zhu, Xiangru; Wu, Haiyan; Yang, Suyong; Gu, Ruolei

2016-01-01

According to the three-tier hierarchy of motivational potency in the self system, the self can be divided into individual self, relational self, and collective self, and individual self is at the top of the motivational hierarchy in Western culture. However, the motivational primacy of the individual self is challenged in Chinese culture, which raises the question about whether the three-tier hierarchy of motivational potency in the self system can be differentiated in the collectivist brain. The present study recorded the event-related potentials (ERPs) to evaluate brain responses when participants gambled for individual self, for a close friend (relational self), or for the class (collective self). The ERP results showed that when outcome feedback was positive, gambling for individual self evoked a larger reward positivity compared with gambling for a friend or for the class, while there is no difference between the latter two conditions. In contrast, when outcome feedback was negative, no significant effect was found between conditions. The present findings provide direct electrophysiological evidence that individual self is at the top of the three-tier hierarchy of the motivational system in the collectivist brain, which supports the classical pancultural view that individual self has motivational primacy.

Development of a serology-based assay for efficacy evaluation of a lactococcicosis vaccine in Seriola fish.

PubMed

Nakajima, Nao; Kawanishi, Michiko; Imamura, Saiki; Hirano, Fumiya; Uchiyama, Mariko; Yamamoto, Kinya; Nagai, Hidetaka; Futami, Kunihiko; Katagiri, Takayuki; Maita, Masashi; Kijima, Mayumi

2014-05-01

Lactococcicosis is an infection caused by the bacterium Lactococcus garvieae and creates serious economic damage to cultured marine and fresh water fish industries. The use of the assay currently applied to evaluate the potency of the lactococcicosis vaccine is contingent upon meeting specific parameters after statistical analysis of the percent survival of the vaccinated yellowtail or greater amberjack fish after challenge with a virulent strain of L. garvieae. We found that measuring the serological response with a quantitative agglutinating antibody against the L. garvieae antigen (phenotype KG+) was an effective method of monitoring the potency of lactococcicosis vaccines. Vaccinated fish had significantly higher antibody titers than control fish when the L. garvieae Lg2-S strain was used as an antigen. Furthermore, the titer of the KG + agglutinating antibody was correlated with vaccine potency, and the cut-off titer was determined by comparing the data with those from the challenge test. An advantage of the proposed serology-based potency assay is that it will contribute to reduced numbers of animal deaths during vaccine potency evaluations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Developing tools for risk assessment in protected species: relative potencies inferred from competitive binding of halogenated aromatic hydrocarbons to aryl hydrocarbon receptors from beluga (Delphinapterus leucas) and mouse

PubMed Central

Jensen, Brenda A.; Reddy, Christopher M.; Nelson, Robert K.; Hahn, Mark E.

2011-01-01

Persistent organic pollutants such as halogenated aromatic hydrocarbons (HAHs) biomagnify in food webs and accumulate to high concentrations in top predators like odontocete cetaceans (toothed whales). The most toxic HAHs are the 2,3,7,8-substituted halogenated dibenzo-p-dioxins and furans, and non-ortho-substituted polychlorinated biphenyls (PCBs), which exert their effects via the aryl hydrocarbon receptor (AHR). Understanding the impact of HAHs in wildlife is limited by the lack of taxon-specific information about the relative potencies of toxicologically important congeners. To assess whether Toxic Equivalency Factors (TEFs) determined in rodents are predictive of HAH relative potencies in a cetacean, we used beluga and mouse AHRs expressed in vitro from cloned cDNAs to measure the relative AHR-binding affinities of ten HAHs from five different structural classes. The rank order of mean IC50s for competitive binding to beluga AHR was: TCDD

Developing tools for risk assessment in protected species: Relative potencies inferred from competitive binding of halogenated aromatic hydrocarbons to aryl hydrocarbon receptors from beluga (Delphinapterus leucas) and mouse.

PubMed

Jensen, Brenda A; Reddy, Christopher M; Nelson, Robert K; Hahn, Mark E

2010-11-01

Persistent organic pollutants such as halogenated aromatic hydrocarbons (HAHs) biomagnify in food webs and accumulate to high concentrations in top predators like odontocete cetaceans (toothed whales). The most toxic HAHs are the 2,3,7,8-substituted halogenated dibenzo-p-dioxins and furans, and non-ortho-substituted polychlorinated biphenyls (PCBs), which exert their effects via the aryl hydrocarbon receptor (AHR). Understanding the impact of HAHs in wildlife is limited by the lack of taxon-specific information about the relative potencies of toxicologically important congeners. To assess whether Toxic Equivalency Factors (TEFs) determined in rodents are predictive of HAH relative potencies in a cetacean, we used beluga and mouse AHRs expressed in vitro from cloned cDNAs to measure the relative AHR-binding affinities of ten HAHs from five different structural classes. The rank order of mean IC(50)s for competitive binding to beluga AHR was: TCDD

Work-group characteristics and performance in collectivistic and individualistic cultures.

PubMed

Sosik, John J; Jung, Dong I

2002-02-01

The authors conducted a cross-cultural longitudinal investigation of the effects of culture (individualism-collectivism dichotomy) on group characteristics (functional heterogeneity, preference for teamwork, group potency, outcome expectation) and on performance of 83 work groups performing 2 decision-making tasks over a 15-week period. The individualists (U.S. students) reported higher levels of functional heterogeneity and group potency and attained higher levels of group performance than did the collectivists (Korean students). In addition, culture and time interacted to influence ratings of group potency and outcome expectation. The difference in ratings of group potency between individualists and collectivists increased over time. Outcome expectation was greater among the collectivists in Time 1 and among the individualists in Time 2. The authors discuss implications for future cross-cultural group research and international management.

Application of agonist-receptor modeling to the sweetness synergy between high fructose corn syrup and sucralose, and between high-potency sweeteners.

PubMed

Wolf, P A; Bridges, J R; Wicklund, R

2010-03-01

The agonist-receptor-transducer model of D. Ennis is applied to beverage formulations sweetened with high fructose corn syrup, sucralose, and other high-potency sweeteners, confirming the utility of the model, and supports the growing volume of evidence for multiple binding sites on the sweetness receptor. The model is further simplified to require less parameters for other sweetener blend systems whenever potency information is available for the single sweeteners.

Zoster vaccine (Zostavax): a review of its use in preventing herpes zoster and postherpetic neuralgia in older adults.

PubMed

Sanford, Mark; Keating, Gillian M

2010-02-01

Individuals who have been infected with varicella zoster virus (VZV) are at risk for developing herpes zoster and this risk appears to be related to a decline in VZV-specific cell-mediated immunity (CMI). Zostavax (zoster vaccine) is a one-dose, high-potency, live, attenuated VZV vaccine that boosts VZV-specific CMI and this is its presumed mechanism of action. Zoster vaccine is registered in the EU for use in adults aged >or=50 years for the prevention of herpes zoster and herpes zoster-related postherpetic neuralgia. In the Shingles Prevention Study, a placebo-controlled trial in adults aged >or=60 years (n = 38 546), zoster vaccine led to a sustained boost of VZV-specific CMI. Over a mean herpes zoster surveillance period of 3.1 years, zoster vaccine reduced the herpes zoster-related burden of illness by 61%, reduced the incidence of herpes zoster by 51% and reduced the incidence of postherpetic neuralgia by 67%. Zoster vaccine recipients who developed herpes zoster had a shorter illness duration and severity than placebo recipients who developed herpes zoster. Zoster vaccine had continuing efficacy in a Shingles Prevention Study subpopulation followed for 7 years post-vaccination. Zoster vaccine was generally well tolerated in older adults. While cost-effectiveness estimates in pharmacoeconomic analyses varied widely according to vaccine and herpes zoster parameter cost/benefit estimates, an analysis from a UK perspective found a zoster vaccine immunization programme in adults aged 65 years to be cost effective. In older adults, the zoster vaccine has the potential to significantly reduce the herpes zoster burden of illness by decreasing the incidence of herpes zoster or reducing its severity.

Seborrheic dermatitis: an update.

PubMed

Bukvić Mokos, Zrinka; Kralj, Martina; Basta-Juzbašić, Aleksandra; Lakoš Jukić, Ines

2012-01-01

Seborrheic dermatitis is a chronic relapsing inflammatory skin disorder clinically characterized by scaling and poorly defined erythematous patches. The prevalence of adult seborrheic dermatitis is estimated at 5%. Although the exact cause of seborrheic dermatitis has yet to be understood, Malassezia yeasts, hormones (androgens), sebum levels and immune response are known to play important roles in its development. Additional factors including drugs, winter temperatures and stress may exacerbate seborrheic dermatitis. A variety of treatment modalities are available, including antifungal agents, topical low-potency steroids and calcineurin inhibitors (immunomodulators). This review summarizes current knowledge on the etiopathogenesis and therapy of adult seborrheic dermatitis.

Methadone detoxification of tramadol dependence.

PubMed

Leo, R J; Narendran, R; DeGuiseppe, B

2000-10-01

Tramadol hydrochloride is a centrally acting analgesic with a partial affinity for the opiate receptor (mu), having an analgesic potency estimated to be one tenth that of morphine. While preclinical investigations suggested that abuse liability associated with tramadol use is low, there are increasing numbers of cases reported to the U.S. Food and Drug Administration of abuse, dependence, and withdrawal associated with tramadol use. A case of a patient with tramadol dependence requiring detoxification with methadone is presented. Acute management of significant tramadol dependence has not yet been reported in the literature. Long-term treatment issues are also discussed.

Freeze-thaw stress of Alhydrogel ® alone is sufficient to reduce the immunogenicity of a recombinant hepatitis B vaccine containing native antigen.

PubMed

Clapp, Tanya; Munks, Michael W; Trivedi, Ruchit; Kompella, Uday B; Braun, LaToya Jones

2014-06-24

Preventing losses in vaccine potency due to accidental freezing has recently become a topic of interest for improving vaccines. All vaccines with aluminum-containing adjuvants are susceptible to such potency losses. Recent studies have described excipients that protect the antigen from freeze-induced inactivation, prevent adjuvant agglomeration and retain potency. Although these strategies have demonstrated success, they do not provide a mechanistic understanding of freeze-thaw (FT) induced potency losses. In the current study, we investigated how adjuvant frozen in the absence of antigen affects vaccine immunogenicity and whether preventing damage to the freeze-sensitive recombinant hepatitis B surface antigen (rHBsAg) was sufficient for maintaining vaccine potency. The final vaccine formulation or Alhydrogel(®) alone was subjected to three FT-cycles. The vaccines were characterized for antigen adsorption, rHBsAg tertiary structure, particle size and charge, adjuvant elemental content and in-vivo potency. Particle agglomeration of either vaccine particles or adjuvant was observed following FT-stress. In vivo studies demonstrated no statistical differences in IgG responses between vaccines with FT-stressed adjuvant and no adjuvant. Adsorption of rHBsAg was achieved; regardless of adjuvant treatment, suggesting that the similar responses were not due to soluble antigen in the frozen adjuvant-containing formulations. All vaccines with adjuvant, including the non-frozen controls, yielded similar, blue-shifted fluorescence emission spectra. Immune response differences could not be traced to differences in the tertiary structure of the antigen in the formulations. Zeta potential measurements and elemental content analyses suggest that FT-stress resulted in a significant chemical alteration of the adjuvant surface. This data provides evidence that protecting a freeze-labile antigen from subzero exposure is insufficient to maintain vaccine potency. Future studies should focus on adjuvant protection. To our knowledge, this is the first study to systematically investigate how FT-stress to adjuvant alone affects immunogenicity. It provides definitive evidence that this damage is sufficient to reduce vaccine potency. Copyright © 2014 Elsevier Ltd. All rights reserved.

TWO-WEEK INHALATION EXPOSURE OF RATS TO LIBBY AMPHIBOLE (LA) AND AMOSITE ASBESTOS

EPA Science Inventory

The relative potency of LA compared to UICC amosite was assessed in a subacute inhalation study designed to set exposure levels for a future subchronic study. Male F344 rats (n=7/group) were exposed nose-only to air (control), 3 concentrations of LA, or I concentration of amosite...

Relative potencies of gypsy moth nucleopolyhedrovirus genotypes isolated from Gypchek

Treesearch

J.D. Podgwaite; R.T. Zerillo; J.M. Slavicek; N. Hayes-Plazolles

2011-01-01

Gypchek is a gypsy moth (Lymantria dispar L.) - specific biopesticide whose primary use is for treating areas where environmental concerns outweigh the use of broad-spectrum pesticides for gypsy moth management. Gypchek is a lyophilized powder produced from larvae that have been infected with the gypsy moth nucleopolyhedrovirus (LdMNPV). The product...

COMPARATIVE POTENCY METHOD FOR CANCER RISK ASSESSMENT: CLARIFICATION OF THE RATIONALE, THEORETICAL BASIS, AND APPLICATION TO DIESEL PARTICULATE EMISSIONS

EPA Science Inventory

The rapid increase in new combustion technologies and new fuels for automobiles, residential and industrial heating, and other energy-related processes poses a particularly unique problem for both the scientific assessment of risk and the regulatory decision-making process that m...

Grape seed and tea extracts and catechin 3-gallates are potent inhibitors of α-amylase and α-glucosidase activity.

PubMed

Yilmazer-Musa, Meltem; Griffith, Anneke M; Michels, Alexander J; Schneider, Erik; Frei, Balz

2012-09-12

This study evaluated the inhibitory effects of plant-based extracts (grape seed, green tea, and white tea) and their constituent flavan-3-ol monomers (catechins) on α-amylase and α-glucosidase activity, two key glucosidases required for starch digestion in humans. To evaluate the relative potency of extracts and catechins, their concentrations required for 50 and 90% inhibition of enzyme activity were determined and compared to the widely used pharmacological glucosidase inhibitor, acarbose. Maximum enzyme inhibition was used to assess relative inhibitory efficacy. Results showed that grape seed extract strongly inhibited both α-amylase and α-glucosidase activity, with equal and much higher potency, respectively, than acarbose. Whereas tea extracts and catechin 3-gallates were less effective inhibitors of α-amylase, they were potent inhibitors of α-glucosidase. Nongallated catechins were ineffective. The data show that plant extracts containing catechin 3-gallates, in particular epigallocatechin gallate, are potent inhibitors of α-glucosidase activity and suggest that procyanidins in grape seed extract strongly inhibit α-amylase activity.

Actions of piperidine alkaloid teratogens at fetal nicotinic acetylcholine receptors.

PubMed

Green, Benedict T; Lee, Stephen T; Panter, Kip E; Welch, Kevin D; Cook, Daniel; Pfister, James A; Kem, William R

2010-01-01

Teratogenic alkaloids are found in many species of plants including Conium maculatum L., Nicotiana glauca, Nicotiana tabaccum, and multiple Lupinus spp. Fetal musculoskeletal defects produced by alkaloids from these plants include arthrogyropisis, scoliosis, torticollis, kyposis, lordosis, and cleft palate. A pharmacodynamic comparison of the alkaloids ammodendrine, anabasine, anabaseine, anagyrine, and coniine in SH-SY5Y cells and TE-671 cells was made. These alkaloids and their enantiomers were more effective in depolarizing TE-671 cells which express the human fetal-muscle type nicotinic acetylcholine receptor (nAChR) relative to SH-SY5Y cells which predominately express autonomic nAChRs. The rank order of potency in TE-671 cells was: anabaseine>(+)-anabasine>(-)-anabasine > (+/-)-anabasine>anagyrine>(-)-coniine > (+/-)-coniine>(+)-coniine>(+/-)-ammodendrine>(+)-ammodendrine. The rank order potency in SH-SY5Y cells was: anabaseine>(+)-anabasine>(-)-coniine>(+)-coniine>(+)-ammodendrine>anagyrine>(-)-anabasine>(+/-)-coniine>(+/-)-anabasine>(-)-ammodendrine. The actions of these alkaloids at nAChRs in both cell lines could be distinguished by their maximum effects in depolarizing cell membrane potential. The teratogenic action of these compounds may be related to their ability to activate and subsequently desensitize nAChRs.

Carcinogenicity and Mutagenicity Data: New Initiatives to ...

EPA Pesticide Factsheets

Currents models for prediction of chemical carcinogenicity and mutagenicity rely upon a relatively small number of publicly available data resources, where the data being modeled are highly summarized and aggregated representations of the actual experimental results. A number of new initiatives are underway to improve access to existing public carcinogenicity and mutagenicity data for use in modeling, as well as to encourage new approaches to the use of data in modeling. Rodent bioassay results from the NIEHS National Toxicology Program (NTP) and the Berkeley Carcinogenic Potency Database (CPDB) have provided the largest public data resources for building carcinogenicity prediction models to date. However, relatively few and limited representations of these data have actually informed existing models. Initiatives, such as EPA's DSSTox Database Network, offer elaborated and quality reviewed presentations of the CPDB and expanded data linkages and coverage of chemical space for carcinogenicity and mutagenicity. In particular the latest published DSSTox CPDBAS structure-data file includes a number of species-specific and summary activity fields, including a species-specific normalized score for carcinogenic potency (TD50) and various weighted summary activities. These data are being incorporated into PubChem to provide broad

Induction of Fetal Hemoglobin by Propionic and Butyric Acid Derivatives: Correlations between Chemical Structure and Potency of Hb F Induction1

PubMed Central

Liakopoulou, Effie; Li, Qiliang; Stamatoyannopoulos, George

2010-01-01

Short-chain fatty acids (C2-C9) induce fetal hemoglobin synthesis in primary cell cultures, primates, and patients. We carried out experiments to test whether relationships exist between chemical structure and the Hb F-inducing potential of several short-chain fatty acid derivatives. BFUe cultures were performed in the presence of propionic and butyric congeners, covering the full spectrum of substitutions of these molecules, including polar and non-polar groups, esters, and double bonds. We found that the fetal hemoglobin inducibility is related to the chemical structure of the inducing compound. This structure–activity relation depends on the length of carbon chain, the nature of the substitutions, and the position of more potent substitutions on the carbon chain. It appears that substitutions enhancing the inducibility of these compounds are (with decreasing potency): methyl > phenyl > hydroxy ≫ amino groups. Placement of these substitutions at a position distal to the carboxyl group enhances γ-globin inducibility. Presence of the carboxyl group is prerequisite for γ-globin inducibility. PMID:12482403

Human blood metabolite timetable indicates internal body time

PubMed Central

Kasukawa, Takeya; Sugimoto, Masahiro; Hida, Akiko; Minami, Yoichi; Mori, Masayo; Honma, Sato; Honma, Ken-ichi; Mishima, Kazuo; Soga, Tomoyoshi; Ueda, Hiroki R.

2012-01-01

A convenient way to estimate internal body time (BT) is essential for chronotherapy and time-restricted feeding, both of which use body-time information to maximize potency and minimize toxicity during drug administration and feeding, respectively. Previously, we proposed a molecular timetable based on circadian-oscillating substances in multiple mouse organs or blood to estimate internal body time from samples taken at only a few time points. Here we applied this molecular-timetable concept to estimate and evaluate internal body time in humans. We constructed a 1.5-d reference timetable of oscillating metabolites in human blood samples with 2-h sampling frequency while simultaneously controlling for the confounding effects of activity level, light, temperature, sleep, and food intake. By using this metabolite timetable as a reference, we accurately determined internal body time within 3 h from just two anti-phase blood samples. Our minimally invasive, molecular-timetable method with human blood enables highly optimized and personalized medicine. PMID:22927403

Hydrophobicity – Shake Flasks, Protein Folding and Drug Discovery

PubMed Central

Sarkar, Aurijit; Kellogg, Glen E.

2009-01-01

Hydrophobic interactions are some of the most important interactions in nature. They are the primary driving force in a number of phenomena. This is mostly an entropic effect and can account for a number of biophysical events such as protein-protein or protein-ligand binding that are of immense importance in drug design. The earliest studies on this phenomenon can be dated back to the end of the 19th century when Meyer and Overton independently correlated the hydrophobic nature of gases to their anesthetic potency. Since then, significant progress has been made in this realm of science. This review briefly traces the history of hydrophobicity research along with the theoretical estimation of partition coefficients. Finally, the application of hydrophobicity estimation methods in the field of drug design and protein folding is discussed. PMID:19929828

Polycyclic aromatic hydrocarbons as skin carcinogens: Comparison of benzo[a]pyrene, dibenzo[def,p]chrysene and three environmental mixtures in the FVB/N mouse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siddens, Lisbeth K.; Larkin, Andrew; Superfund Research Center, Oregon State University

2012-11-01

The polycyclic aromatic hydrocarbon (PAH), benzo[a]pyrene (BaP), was compared to dibenzo[def,p]chrysene (DBC) and combinations of three environmental PAH mixtures (coal tar, diesel particulate and cigarette smoke condensate) using a two stage, FVB/N mouse skin tumor model. DBC (4 nmol) was most potent, reaching 100% tumor incidence with a shorter latency to tumor formation, less than 20 weeks of 12-O-tetradecanoylphorbol-13-acetate (TPA) promotion compared to all other treatments. Multiplicity was 4 times greater than BaP (400 nmol). Both PAHs produced primarily papillomas followed by squamous cell carcinoma and carcinoma in situ. Diesel particulate extract (1 mg SRM 1650b; mix 1) did notmore » differ from toluene controls and failed to elicit a carcinogenic response. Addition of coal tar extract (1 mg SRM 1597a; mix 2) produced a response similar to BaP. Further addition of 2 mg of cigarette smoke condensate (mix 3) did not alter the response with mix 2. PAH-DNA adducts measured in epidermis 12 h post initiation and analyzed by {sup 32}P post‐labeling, did not correlate with tumor incidence. PAH‐dependent alteration in transcriptome of skin 12 h post initiation was assessed by microarray. Principal component analysis (sum of all treatments) of the 922 significantly altered genes (p < 0.05), showed DBC and BaP to cluster distinct from PAH mixtures and each other. BaP and mixtures up-regulated phase 1 and phase 2 metabolizing enzymes while DBC did not. The carcinogenicity with DBC and two of the mixtures was much greater than would be predicted based on published Relative Potency Factors (RPFs). -- Highlights: ► Dibenzo[def,p]chrysene (DBC), 3 PAH mixtures, benzo[a]pyrene (BaP) were compared. ► DBC and 2 PAH mixtures were more potent than Relative Potency Factor estimates. ► Transcriptome profiles 12 hours post initiation were analyzed by microarray. ► Principle components analysis of alterations revealed treatment-based clustering. ► DBC gave a unique pattern of gene alterations compared to BaP and PAH mixtures.« less

Crowdsourcing black market prices for prescription opioids.

PubMed

Dasgupta, Nabarun; Freifeld, Clark; Brownstein, John S; Menone, Christopher Mark; Surratt, Hilary L; Poppish, Luke; Green, Jody L; Lavonas, Eric J; Dart, Richard C

2013-08-16

Prescription opioid diversion and abuse are major public health issues in the United States and internationally. Street prices of diverted prescription opioids can provide an indicator of drug availability, demand, and abuse potential, but these data can be difficult to collect. Crowdsourcing is a rapid and cost-effective way to gather information about sales transactions. We sought to determine whether crowdsourcing can provide accurate measurements of the street price of diverted prescription opioid medications. To assess the possibility of crowdsourcing black market drug price data by cross-validation with law enforcement officer reports. Using a crowdsourcing research website (StreetRx), we solicited data about the price that site visitors paid for diverted prescription opioid analgesics during the first half of 2012. These results were compared with a survey of law enforcement officers in the Researched Abuse, Diversion, and Addiction-Related Surveillance (RADARS) System, and actual transaction prices on a "dark Internet" marketplace (Silk Road). Geometric means and 95% confidence intervals were calculated for comparing prices per milligram of drug in US dollars. In a secondary analysis, we compared prices per milligram of morphine equivalent using standard equianalgesic dosing conversions. A total of 954 price reports were obtained from crowdsourcing, 737 from law enforcement, and 147 from the online marketplace. Correlations between the 3 data sources were highly linear, with Spearman rho of 0.93 (P<.001) between crowdsourced and law enforcement, and 0.98 (P<.001) between crowdsourced and online marketplace. On StreetRx, the mean prices per milligram were US$3.29 hydromorphone, US$2.13 buprenorphine, US$1.57 oxymorphone, US$0.97 oxycodone, US$0.96 methadone, US$0.81 hydrocodone, US$0.52 morphine, and US$0.05 tramadol. The only significant difference between data sources was morphine, with a Drug Diversion price of US$0.67/mg (95% CI 0.59-0.75) and a Silk Road price of US$0.42/mg (95% CI 0.37-0.48). Street prices generally followed clinical equianalgesic potency. Crowdsourced data provide a valid estimate of the street price of diverted prescription opioids. The (ostensibly free) black market was able to accurately predict the relative pharmacologic potency of opioid molecules.

Hydraphiles enhance antimicrobial potency against Escherichia coli, Pseudomonas aeruginosa, and Bacillus subtilis.

PubMed

Patel, Mohit B; Garrad, Evan C; Stavri, Ariel; Gokel, Michael R; Negin, Saeedeh; Meisel, Joseph W; Cusumano, Zachary; Gokel, George W

2016-06-15

Hydraphiles are synthetic amphiphiles that form ion-conducting pores in liposomal membranes. These pores exhibit open-close behavior when studied by planar bilayer conductance techniques. In previous work, we showed that when co-administered with various antibiotics to the DH5α strain of Escherichia coli, they enhanced the drug's potency. We report here potency enhancements at low concentrations of hydraphiles for the structurally and mechanistically unrelated antibiotics erythromycin, kanamycin, rifampicin, and tetracycline against Gram negative E. coli (DH5α and K-12) and Pseudomonas aeruginosa, as well as Gram positive Bacillus subtilis. Earlier work suggested that potency increases correlated to ion transport function. The data presented here comport with the function of hydraphiles to enhance membrane permeability in addition to, or instead of, their known function as ion conductors. Copyright © 2016 Elsevier Ltd. All rights reserved.

Statin-Associated Muscle-Related Adverse Effects: A Case Series of 354 Patients

PubMed Central

Cham, Stephanie; Evans, Marcella A.; Denenberg, Julie O.; Golomb, Beatrice A.

2016-01-01

Study Objective To characterize the properties and natural history of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin)-associated muscle-related adverse effects (MAEs). Design Patient-targeted postmarketing adverse-effect surveillance approach coupling survey design with an open-ended narrative. Setting University-affiliated health care system. Subjects Three hundred fifty-four patients (age range 34–86 yrs) who self-reported muscle-related problems associated with statin therapy. Measurements and Main Results Patients with perceived statin-associated MAEs completed a survey assessing statin drugs and dosages; characteristics of the MAEs; time course of onset, resolution, or recurrence; and impact on quality of life (QOL). Cases were assessed for putative drug adverse-effect causality by using the Naranjo adverse drug reaction probability scale criteria and were evaluated for inclusion in groups for which mortality benefit with statins has been shown. Patients reported muscle pain (93%), fatigue (88%), and weakness (85%). Three hundred patients (85%) met literature criteria for probable or definite drug adverse-effect causality. Ninety-four percent of atorvastatin usages (240/255) generated MAEs versus 61% of lovastatin usages (38/62, p<0.0001). Higher potency statins reproduced MAEs in 100% of 39 rechallenges versus 73% (29/40) with lower potency rechallenges (p<0.01). Time course of onset after statin initiation varied (median 14 wks); some MAEs occurred after long-term symptom-free use. Recurrence with rechallenge had a significantly shorter latency to onset (median 2 wks). The MAEs adversely affected all assessed functional and QOL domains. Most patients with probable or definite MAEs were in categories for which available randomized controlled trial evidence shows no trend to all-cause mortality benefit with statin therapy. Conclusion This study complements available information on the properties and natural history of statin-associated MAEs, affirming dose dependence and strong QOL impact. The data indicating a dose-dependent relationship between MAE risk and recurrence suggest lower potency statins or discontinuation may bear consideration for ameliorating symptoms. PMID:20500044

Statin-associated muscle-related adverse effects: a case series of 354 patients.

PubMed

Cham, Stephanie; Evans, Marcella A; Denenberg, Julie O; Golomb, Beatrice A

2010-06-01

To characterize the properties and natural history of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin)-associated muscle-related adverse effects (MAEs). Patient-targeted postmarketing adverse-effect surveillance approach coupling survey design with an open-ended narrative. University-affiliated health care system. Three hundred fifty-four patients (age range 34-86 yrs) who self-reported muscle-related problems associated with statin therapy. Patients with perceived statin-associated MAEs completed a survey assessing statin drugs and dosages; characteristics of the MAEs; time course of onset, resolution, or recurrence; and impact on quality of life (QOL). Cases were assessed for putative drug adverse-effect causality by using the Naranjo adverse drug reaction probability scale criteria and were evaluated for inclusion in groups for which mortality benefit with statins has been shown. Patients reported muscle pain (93%), fatigue (88%), and weakness (85%). Three hundred patients (85%) met literature criteria for probable or definite drug adverse-effect causality. Ninety-four percent of atorvastatin usages (240/255) generated MAEs versus 61% of lovastatin usages (38/62, p<0.0001). Higher potency statins reproduced MAEs in 100% of 39 rechallenges versus 73% (29/40) with lower potency rechallenges (p<0.01). Time course of onset after statin initiation varied (median 14 wks); some MAEs occurred after long-term symptom-free use. Recurrence with rechallenge had a significantly shorter latency to onset (median 2 wks). The MAEs adversely affected all assessed functional and QOL domains. Most patients with probable or definite MAEs were in categories for which available randomized controlled trial evidence shows no trend to all-cause mortality benefit with statin therapy. This study complements available information on the properties and natural history of statin-associated MAEs, affirming dose dependence and strong QOL impact. The data indicating a dose-dependent relationship between MAE risk and recurrence suggest lower potency statins or discontinuation may bear consideration for ameliorating symptoms.

Speed of onset of bronchodilator response to salbutamol inhaled via different devices in asthmatics: a bioassay based on functional antagonism

PubMed Central

Lavorini, Federico; Geri, Pietro; Mariani, Laura; Marmai, Cecilia; Maluccio, Nazzarena Maria; Pistolesi, Massimo; Fontana, Giovanni A

2006-01-01

Aims To evaluate the speed of onset of bronchodilation following salbutamol administered via a metered-dose inhaler with a spacer (pMDI + Volumatic) and a dry-powder inhaler (Diskus), as well as the relative potencies of these devices in asthmatic patients with methacholine-induced bronchoconstriction. Methods Eighteen patients inhaled methacholine (MCh) until FEV1 decreased by 35% of control. Following administration of placebo, 200 µg salbutamol or 400 µg salbutamol through the pMDI + Volumatic or the Diskus, we calculated the time elapsed from drug administration and the appearance of a 90% increase in post-MCh forced vital capacity (FVC), FEV1 and volume-adjusted mid-expiratory flow (recovery times). The salbutamol doses to be delivered by the two inhalation devices to achieve similar recovery times and the relative potencies of the devices were calculated by using the 2-by-2 Finney parallel regression method. Results For all functional variables, recovery times were significantly (P < 0.01) shorter in pMDI + Volumatic than Diskus trials. The salbutamol doses to be delivered by the Diskus to achieve recovery times for FVC, FEV1 and volume-adjusted mid-expiratory flow similar to those obtained with 200 µg salbutamol administered via the pMDI + Volumatic were 558 (95% CI 537, 579) µg, 395 (95% CI 388, 404) µg and 404 (95% CI 393, 415) µg, respectively, and corresponded to relative potencies of 2.79 (95% CI 2.68, 2.90), 1.98 (95% CI 1.94, 2.02), and 2.02 (95% CI 1.96, 2.07). Conclusions Administration of salbutamol via the pMDI + Volumatic provides faster reversal of induced bronchoconstriction than via the Diskus. The salbutamol dose targeting the lungs with the pMDI + Volumatic is approximately twice that with the Diskus. PMID:16995861

Kinome-wide selectivity profiling of ATP-competitive mammalian target of rapamycin (mTOR) inhibitors and characterization of their binding kinetics.

PubMed

Liu, Qingsong; Kirubakaran, Sivapriya; Hur, Wooyoung; Niepel, Mario; Westover, Kenneth; Thoreen, Carson C; Wang, Jinhua; Ni, Jing; Patricelli, Matthew P; Vogel, Kurt; Riddle, Steve; Waller, David L; Traynor, Ryan; Sanda, Takaomi; Zhao, Zheng; Kang, Seong A; Zhao, Jean; Look, A Thomas; Sorger, Peter K; Sabatini, David M; Gray, Nathanael S

2012-03-23

An intensive recent effort to develop ATP-competitive mTOR inhibitors has resulted in several potent and selective molecules such as Torin1, PP242, KU63794, and WYE354. These inhibitors are being widely used as pharmacological probes of mTOR-dependent biology. To determine the potency and specificity of these agents, we have undertaken a systematic kinome-wide effort to profile their selectivity and potency using chemical proteomics and assays for enzymatic activity, protein binding, and disruption of cellular signaling. Enzymatic and cellular assays revealed that all four compounds are potent inhibitors of mTORC1 and mTORC2, with Torin1 exhibiting ∼20-fold greater potency for inhibition of Thr-389 phosphorylation on S6 kinases (EC(50) = 2 nM) relative to other inhibitors. In vitro biochemical profiling at 10 μM revealed binding of PP242 to numerous kinases, although WYE354 and KU63794 bound only to p38 kinases and PI3K isoforms and Torin1 to ataxia telangiectasia mutated, ATM and Rad3-related protein, and DNA-PK. Analysis of these protein targets in cellular assays did not reveal any off-target activities for Torin1, WYE354, and KU63794 at concentrations below 1 μM but did show that PP242 efficiently inhibited the RET receptor (EC(50), 42 nM) and JAK1/2/3 kinases (EC(50), 780 nM). In addition, Torin1 displayed unusually slow kinetics for inhibition of the mTORC1/2 complex, a property likely to contribute to the pharmacology of this inhibitor. Our results demonstrated that, with the exception of PP242, available ATP-competitive compounds are highly selective mTOR inhibitors when applied to cells at concentrations below 1 μM and that the compounds may represent a starting point for medicinal chemistry efforts aimed at developing inhibitors of other PI3K kinase-related kinases.

Specific binding of (/sup 3/H-Tyr8)physalaemin to rat submaxillary gland substance P receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bahouth, S.W.; Lazaro, D.M.; Brundish, D.E.

1985-01-01

(/sup 3/H)Physalaemin ((/sup 3/H)PHY) binds to a single class of noninteracting sites on rat submaxillary gland membranes suspended in high ionic strength media with a KD of 2.7 nM, a Bmax of 240 fmol/mg of protein, and low nonspecific binding. The relative potencies of substance P (SP) and its fragments in competing with (/sup 3/H)PHY correlate with their relative salivation potencies. This indicates that (/sup 3/H)PHY interacts with a physiologically relevant SP receptor. In low ionic strength media, the KD of (/sup 3/H)PHY does not change, but SP and some of its fragments are more potent than PHY in competingmore » with (/sup 3/H) PHY. Computer-assisted analysis of (/sup 3/H)PHY and (/sup 3/H)SP binding in high and low ionic strength media demonstrated that both peptides are equipotent in high ionic strength but that the affinity of SP increases by 70-fold in low ionic strength. The SP fragments that contain a basic residue in positions 1 and/or 3 also display an increased affinity in low ionic strength. These findings document that (/sup 3/H)PHY binding in high ionic strength (mu . 0.6) accurately reflects the pharmacological potencies of agonists on the SP-P receptor. The binding of (/sup 3/H)PHY, like that of (/sup 3/H)SP, increases by the addition of divalent cations (Mg2+ greater than Ca2+ greater than Mn2+). Guanine nucleotides decrease (/sup 3/H)PHY binding by decreasing the Bmax to the same level (160 fmol/mg of protein), in the presence or absence of Mg2+.« less

Phosphatidylinositol 4-Kinase III Beta Is Essential for Replication of Human Rhinovirus and Its Inhibition Causes a Lethal Phenotype In Vivo

PubMed Central

Spickler, Catherine; Lippens, Julie; Laberge, Marie-Kristine; Desmeules, Sophie; Bellavance, Édith; Garneau, Michel; Guo, Tim; Hucke, Oliver; Leyssen, Pieter; Neyts, Johan; Vaillancourt, Fréderic H.; Décor, Anne; O'Meara, Jeff; Franti, Michael

2013-01-01

Human rhinovirus (HRV) is the predominant cause of the common cold, but more importantly, infection may have serious repercussions in asthmatics and chronic obstructive pulmonary disorder (COPD) patients. A cell-based antiviral screen against HRV was performed with a subset of our proprietary compound collection, and an aminothiazole series with pan-HRV species and enteroviral activity was identified. The series was found to act at the level of replication in the HRV infectious cycle. In vitro selection and sequencing of aminothiazole series-resistant HRV variants revealed a single-nucleotide mutation leading to the amino acid change I42V in the essential HRV 3A protein. This same mutation has been previously implicated in resistance to enviroxime, a former clinical-stage antipicornavirus agent. Enviroxime-like compounds have recently been shown to target the lipid kinase phosphatidylinositol 4-kinase III beta (PI4KIIIβ). A good correlation between PI4KIIIβ activity and HRV antiviral potency was found when analyzing the data over 80 compounds of the aminothiazole series, covering a 750-fold potency range. The mechanism of action through PI4KIIIβ inhibition was further demonstrated by small interfering RNA (siRNA) knockdown of PI4KB, which reduced HRV replication and also increased the potency of the PI4KIIIβ inhibitors. Inhibitors from two different structural classes with promising pharmacokinetic profiles and with very good selectivity for PI4KIIIβ were used to dissociate compound-related toxicity from target-related toxicity. Mortality was seen in all dosing groups of mice treated with either compound, therefore suggesting that short-term inhibition of PI4KIIIβ is deleterious. PMID:23650168

Structure–Activity Relationship Studies Using Natural and Synthetic Okadaic Acid/Dinophysistoxin Toxins

PubMed Central

Twiner, Michael J.; Doucette, Gregory J.; Pang, Yucheng; Fang, Chao; Forsyth, Craig J.; Miles, Christopher O.

2016-01-01

Okadaic acid (OA) and the closely related dinophysistoxins (DTXs) are algal toxins that accumulate in shellfish and are known serine/threonine protein phosphatase (ser/thr PP) inhibitors. Phosphatases are important modulators of enzyme activity and cell signaling pathways. However, the interactions between the OA/DTX toxins and phosphatases are not fully understood. This study sought to identify phosphatase targets and characterize their structure–activity relationships (SAR) with these algal toxins using a combination of phosphatase activity and cytotoxicity assays. Preliminary screening of 21 human and yeast phosphatases indicated that only three ser/thr PPs (PP2a, PP1, PP5) were inhibited by physiologically saturating concentrations of DTX2 (200 nM). SAR studies employed naturally-isolated OA, DTX1, and DTX2, which vary in degree and/or position of methylation, in addition to synthetic 2-epi-DTX2. OA/DTX analogs induced cytotoxicity and inhibited PP activity with a relatively conserved order of potency: OA = DTX1 ≥ DTX2 >> 2-epi-DTX. The PPs were also differentially inhibited with sensitivities of PP2a > PP5 > PP1. These findings demonstrate that small variations in OA/DTX toxin structures, particularly at the head region (i.e., C1/C2), result in significant changes in toxicological potency, whereas changes in methylation at C31 and C35 (tail region) only mildly affect potency. In addition to this being the first study to extensively test OA/DTX analogs’ activities towards PP5, these data will be helpful for accurately determining toxic equivalence factors (TEFs), facilitating molecular modeling efforts, and developing highly selective phosphatase inhibitors. PMID:27827901

Mutagenicity and in vivo toxicity of combined particulate and semivolatile organic fractions of gasoline and diesel engine emissions.

PubMed

Seagrave, JeanClare; McDonald, Jacob D; Gigliotti, Andrew P; Nikula, Kristen J; Seilkop, Steven K; Gurevich, Michael; Mauderly, Joe L

2002-12-01

Exposure to engine emissions is associated with adverse health effects. However, little is known about the relative effects of emissions produced by different operating conditions, fuels, or technologies. Rapid screening techniques are needed to compare the biological effects of emissions with different characteristics. Here, we examined a set of engine emission samples using conventional bioassays. The samples included combined particulate material and semivolatile organic compound fractions of emissions collected from normal- and high-emitter gasoline and diesel vehicles collected at 72 degrees F, and from normal-emitter groups collected at 30 degrees F. The relative potency of the samples was determined by statistical analysis of the dose-response curves. All samples induced bacterial mutagenicity, with a 10-fold range of potency among the samples. Responses to intratracheal instillation in rats indicated generally parallel rankings of the samples by multiple endpoints reflecting cytotoxic, inflammatory, and lung parenchymal changes, allowing selection of a more limited set of parameters for future studies. The parameters selected to assess oxidative stress and macrophage function yielded little useful information. Responses to instillation indicated little difference in potency per unit of combined particulate material and semivolatile organic compound mass between normal-emitter gasoline and diesel vehicles, or between emissions collected at different temperatures. However, equivalent masses of emissions from high-emitter vehicles of both types were more potent than those from normal-emitters. While preliminary in terms of assessing contributions of different emissions to health hazards, the results indicate that a subset of this panel of assays will be useful in providing rapid, cost-effective feedback on the biological impact of modified technology.

Structure-activity studies of bufokinin, substance P and their C-terminal fragments at bufokinin receptors in the small intestine of the cane toad, Bufo marinus.

PubMed

Liu, Lu; Murray, Michael; Burcher, Elizabeth

2002-01-15

Bufokinin is a substance P-related tachykinin peptide with potent spasmogenic actions, isolated from the intestine of the cane toad, Bufo marinus. Bufokinin acts via a tachykinin receptor with similarities to the mammalian NK(1) receptor. In this structure-activity study of bufokinin, substance P (SP) and their C-terminal fragments, we have used isolated segments and homogenates of toad small intestine to compare the contractile potencies and abilities to compete for the binding of [125I]-Bolton-Hunter bufokinin. In general, potency was very similar in both studies (r=0.956) and was primarily related to peptide length, with the natural undecapeptide tachykinins bufokinin - ranakinin>SP- cod SP -trout SP being most potent. The weakest peptides were [Pro(9)]SP, BUF(7-11) and SP(7-11). Bufokinin fragments (BUF) were approximately equipotent to the corresponding SP fragments, with only BUF(5-11) showing unexpectedly low binding affinity. Data obtained with SP, bufokinin and fragments were subjected to quantitative structure--activity (QSAR) analysis which demonstrated that molecular connectivity and shape descriptors yielded significant regression equations (r approximately 0.90). The predictive capacity of the equations was confirmed using ranakinin, trout SP and cod SP, but not using the synthetic analogs [Pro(9)]SP and [Sar(9)]SP. The study suggests that the full undecapeptide sequence of bufokinin is required for optimal activity, with high potency conferred by Lys(1), Pro(2), Gly(9) and probably Tyr(8). The finding that receptor-ligand interactions were correlated with the shape descriptor 2kappa(alpha) and favored by basic and rigid residues at position 1-3 is consistent with an important role of conformation at the N-terminus of bufokinin.

Potencies of agonists acting at tachykinin receptors in the oestrogen-primed rat uterus: effects of peptidase inhibitors.

PubMed

Fisher, L; Pennefather, J N

1997-09-24

The uterotonic potencies of the naturally occurring mammalian tachykinins and the synthetic subtype-selective agonist analogues of these agents [Lys5,MeLeu9,Nlel0]neurokinin A-(4-10) and [Nle10]neurokinin A-(4-10) (tachykinin NK2 receptor-selective), [Sar9,Met(O2)11]substance P (tachykinin NK1 receptor-selective) and senktide (tachykinin NK3 receptor-selective) were determined using preparations from oestradiol-treated rats. The endopeptidase 24.11 inhibitor, N-[N-[1-(S)-carboxyl-3-phenylpropyl]-(S)-phenyl-alanyl-(S)-isoserine+ ++ (SCH 39370), potentiated responses to neurokinin A, neurokinin B and substance P, but not to [Lys5,MeLeu9,Nle10)]neurokinin A-(4-10) or senktide. [Nle10]neurokinin A-(4-10) effects were potentiated by SCH 39370 with amastatin and those to [Sar9,Met(O2)11]substance P were potentiated by SCH 39370 and captopril in combination. In the presence of optimal concentrations of peptidase inhibitors the relative order of agonist potency was: neurokinin A > substance P > neurokinin B for the naturally occurring mammalian tachykinins and [Lys5,MeLeu9,Nle10]neurokinin A-(4-10) > [Nle10]neurokinin A-(4-10) > [Sar9,Met(O2)11]substance P > senktide for the synthetic tachykinin analogues. Thus, while a tachykinin NK2 receptor predominates in the oestrogen-primed uterus, a tachykinin NK1 receptor may also be present. The non-peptide tachykinin NK3 receptor antagonist, SR 142801, did not antagonise the effects of senktide suggesting that tachykinin NK3 receptors do not mediate its relatively minor effect on the uterus of the oestrogen-primed rat.

Structure-activity relationships of phenothiazines and related drugs for inhibition of protein kinase C.

PubMed

Aftab, D T; Ballas, L M; Loomis, C R; Hait, W N

1991-11-01

Phenothiazines are known to inhibit the activity of protein kinase C. To identify structural features that determine inhibitory activity against the enzyme, we utilized a semiautomated assay [Anal. Biochem. 187:84-88 (1990)] to compare the potency of greater than 50 phenothiazines and related compounds. Potency was decreased by trifluoro substitution at position 2 on the phenothiazine nucleus and increased by quinoid structures on the nucleus. An alkyl bridge of at least three carbons connecting the terminal amine to the nucleus was required for activity. Primary amines and unsubstituted piperazines were the most potent amino side chains. We selected 7,8-dihydroxychlorpromazine (DHCP) (IC50 = 8.3 microM) and 2-chloro-9-(3-[1-piperazinyl]propylidene)thioxanthene (N751) (IC50 = 14 microM) for further study because of their potency and distinct structural features. Under standard (vesicle) assay conditions, DHCP was noncompetitive with respect to phosphatidylserine and a mixed-type inhibitor with respect to ATP. N751 was competitive with respect to phosphatidylserine and noncompetitive with respect to ATP. Using the mixed micelle assay, DHCP was a competitive inhibitor with respect to both phosphatidylserine and ATP. DHCP was selective for protein kinase C compared with cAMP-dependent protein kinase, calmodulin-dependent protein kinase type II, and casein kinase. N751 was more potent against protein kinase C compared with cAMP-dependent protein kinase and casein kinase but less potent against protein kinase C compared with calmodulin-dependent protein kinase type II. DHCP was analyzed for its ability to inhibit different isoenzymes of protein kinase C, and no significant isozyme selectivity was detected. These data provide important information for the rational design of more potent and selective inhibitors of protein kinase C.

Principles for identification of High Potency Category Chemicals for which the Dermal Sensitisation Threshold (DST) approach should not be applied.

PubMed

Roberts, David W; Api, Anne Marie; Safford, Robert J; Lalko, Jon F

2015-08-01

An essential step in ensuring the toxicological safety of chemicals used in consumer products is the evaluation of their skin sensitising potential. The sensitising potency, coupled with information on exposure levels, can be used in a Quantitative Risk Assessment (QRA) to determine an acceptable level of a given chemical in a given product. Where consumer skin exposure is low, a risk assessment can be conducted using the Dermal Sensitisation Threshold (DST) approach, avoiding the need to determine potency experimentally. Since skin sensitisation involves chemical reaction with skin proteins, the first step in the DST approach is to assess, on the basis of the chemical structure, whether the chemical is expected to be reactive or not. Our accompanying publication describes the probabilistic derivation of a DST of 64 μg/cm(2) for chemicals assessed as reactive. This would protect against 95% of chemicals assessed as reactive, but the remaining 5% would include chemicals with very high potency. Here we discuss the chemical properties and structural features of high potency sensitisers, and derive an approach whereby they can be identified and consequently excluded from application of the DST. Copyright © 2015 Elsevier Inc. All rights reserved.

Collaborative studies on the development of national reference standards for potency determination of H7N9 influenza vaccine

PubMed Central

Li, Changgui; Xu, Kangwei; Hashem, Anwar; Shao, Ming; Liu, Shuzhen; Zou, Yong; Gao, Qiang; Zhang, Yongchao; Yuan, Liyong; Xu, Miao; Li, Xuguang; Wang, Junzhi

2015-01-01

The outbreak of human infections of a novel avian influenza virus A (H7N9) prompted the development of the vaccines against this virus. Like all types of influenza vaccines, H7N9 vaccine must be tested for its potency prior to being used in humans. However, the unavailability of international reference reagents for the potency determination of H7N9 vaccines substantially hinders the progress in vaccine development. To facilitate clinical development, we enlisted 5 participants in a collaborative study to develop critical reagents used in Single Radial Immunodiffusion (SRID), the currently acceptable assay for potency determination of influenza vaccine. Specifically, the hemagglutinin (HA) content of one vaccine bulk for influenza A (H7N9), herein designated as Primary Liquid Standard (PLS), was determined by SDS-PAGE. In addition, the freeze-dried antigen references derived from PLS were prepared to enhance the stability for long term storage. The final HA content of lyophilized antigen references were calibrated against PLS by SRID assay in a collaborative study. Importantly, application of these national reference standards to potency analyses greatly facilitated the development of H7N9 vaccines in China. PMID:25970793

[Vasodilative effects of indole alkaloids obtained from domestic plants, Uncaria rhynchophylla Miq. and Amsonia elliptica Roem. et Schult].

PubMed

Ozaki, Y

1990-02-01

Vasodilative effects of hirsutine (HS) and hirsuteine (HST) which were isolated from the domestic plant Uncaria rhynchophylla Miq. and beta-yohimbine (beta-Y) which was isolated from the domestic plant Amsonia elliptica Roem. et Schult. were carried out. In the hind-limb artery of anesthetized dogs, intra-arterial administration of HS, HST and beta-Y caused a vasodilatation. The vasodilative potency of HS was somewhat stronger than that of HST, and the potency of both alkaloids was approximately equal to that of papaverine. The vasodilative effect of beta-Y was similar to that of yohimbine, which is considered to be derived from its alpha-adrenoceptor blocking effect, and the potency of both alkaloids was approximately the same, while the effect of beta-Y was stronger than that of papaverine. In the coronary artery, HS showed a vasodilatation and its potency was weaker than that of papaverine. Also, HS showed the same effect in the cerebral artery, and the potency of HS was approximately the same as that of papaverine. These results suggest that the mode of the vasodilative effect induced by HS may partly differ from that of papaverine.

Drug Stability Analysis by Raman Spectroscopy

PubMed Central

Shende, Chetan; Smith, Wayne; Brouillette, Carl; Farquharson, Stuart

2014-01-01

Pharmaceutical drugs are available to astronauts to help them overcome the deleterious effects of weightlessness, sickness and injuries. Unfortunately, recent studies have shown that some of the drugs currently used may degrade more rapidly in space, losing their potency before their expiration dates. To complicate matters, the degradation products of some drugs can be toxic. Here, we present a preliminary investigation of the ability of Raman spectroscopy to quantify mixtures of four drugs; acetaminophen, azithromycin, epinephrine, and lidocaine, with their primary degradation products. The Raman spectra for the mixtures were replicated by adding the pure spectra of the drug and its degradant to determine the relative percent contributions using classical least squares. This multivariate approach allowed determining concentrations in ~10 min with a limit of detection of ~4% of the degradant. These results suggest that a Raman analyzer could be used to assess drug potency, nondestructively, at the time of use to ensure crewmember safety. PMID:25533308

Discovery, structure-activity relationship, and pharmacological evaluation of (5-substituted-pyrrolidinyl-2-carbonyl)-2-cyanopyrrolidines as potent dipeptidyl peptidase IV inhibitors.

PubMed

Pei, Zhonghua; Li, Xiaofeng; Longenecker, Kenton; von Geldern, Thomas W; Wiedeman, Paul E; Lubben, Thomas H; Zinker, Bradley A; Stewart, Kent; Ballaron, Stephen J; Stashko, Michael A; Mika, Amanda K; Beno, David W A; Long, Michelle; Wells, Heidi; Kempf-Grote, Anita J; Madar, David J; McDermott, Todd S; Bhagavatula, Lakshmi; Fickes, Michael G; Pireh, Daisy; Solomon, Larry R; Lake, Marc R; Edalji, Rohinton; Fry, Elizabeth H; Sham, Hing L; Trevillyan, James M

2006-06-15

A series of (5-substituted pyrrolidinyl-2-carbonyl)-2-cyanopyrrolidine (C5-Pro-Pro) analogues was discovered as dipeptidyl peptidase IV (DPPIV) inhibitors as a potential treatment of diabetes and obesity. X-ray crystallography data show that these inhibitors bind to the catalytic site of DPPIV with the cyano group forming a covalent bond with the serine residue of DPPIV. The C5-substituents make various interactions with the enzyme and affect potency, chemical stability, selectivity, and PK properties of the inhibitors. Optimized analogues are extremely potent with subnanomolar K(i)'s, are chemically stable, show very little potency decrease in the presence of plasma, and exhibit more than 1,000-fold selectivity against related peptidases. The best compounds also possess good PK and are efficacious in lowering blood glucose in an oral glucose tolerance test in ZDF rats.

Pharmacokinetic-pharmacodynamic modeling of morphine-6-glucuronide-induced analgesia in healthy volunteers: absence of sex differences.

PubMed

Romberg, Raymonda; Olofsen, Erik; Sarton, Elise; den Hartigh, Jan; Taschner, Peter E M; Dahan, Albert

2004-01-01

Morphine-6-glucuronide (M6G) is a metabolite of morphine and a micro-opioid agonist. To quantify the potency and speed of onset-offset of M6G and explore putative sex dependency, the authors studied the pharmacokinetics and pharmacodynamics of M6G in volunteers using a placebo-controlled, randomized, double-blind study design. Ten men and 10 women received 0.3 mg/kg intravenous M6G and placebo (two thirds of the dose as bolus, one third as a continuous infusion over 1 h) on separate occasions. For 7 h, pain tolerance was measured using gradually increasing transcutaneous electrical stimulation, and blood samples were obtained. A population pharmacokinetic (inhibitory sigmoid Emax)-pharmacodynamic analysis was used to analyze M6G-induced changes in tolerated stimulus intensity. The improvement in model fits by inclusion of covariate sex was tested for significance. P values less than 0.01 were considered significant. Taking into account previous morphine data, a predictive pharmacokinetic-pharmacodynamic model was constructed to determine the contribution of M6G to morphine analgesia. M6G concentrations did not differ between men and women. M6G caused analgesia significantly greater than that observed with placebo (P < 0.01). The M6G analgesia data were well described by the pharmacokinetic-pharmacodynamic model. The M6G effect site concentration causing a 25% increase in current (C25) was 275 +/- 135 nm (population estimate +/- SE), the blood effect site equilibration half-life was 6.2 +/- 3.3 h, and the steepness parameter was 0.71 +/- 0.18. Intersubject variability was 167% for C25 and 218% for the effect half-life. None of the model parameters showed sex dependency. A cumulative dose of 0.3 mg/kg M6G, given over 1 h, produces long-term analgesia greater than that observed with placebo, with equal dynamics (potency and speed of onset-offset) in men and women. Possible causes for the great intersubject response variability, such as genetic polymorphism of the micro-opioid receptor and placebo-related phenomena, are discussed. The predictive pharmacokinetic-pharmacodynamic model was applied successfully and was used to estimate M6G analgesia after morphine in patients with normal and impaired renal function.

Rationale for Further Medical and Health Research on High-Potency Sweeteners

PubMed Central

2012-01-01

High-potency or artificial sweeteners have historically been considered inert compounds without physiological consequences other than taste sensations. However, recent data suggest that some of these sweeteners have biological effects that may impact human health. Furthermore, there are significant gaps in our current knowledge of the pharmacokinetics of these sweeteners, their potential for “sweetener–drug interactions” and their impact on appetite and body weight regulation. Nine research needs are described that address some of the major unknown issues associated with ingestion of high-potency sweeteners. PMID:22539626

Rationale for further medical and health research on high-potency sweeteners.

PubMed

Schiffman, Susan S

2012-10-01

High-potency or artificial sweeteners have historically been considered inert compounds without physiological consequences other than taste sensations. However, recent data suggest that some of these sweeteners have biological effects that may impact human health. Furthermore, there are significant gaps in our current knowledge of the pharmacokinetics of these sweeteners, their potential for "sweetener-drug interactions" and their impact on appetite and body weight regulation. Nine research needs are described that address some of the major unknown issues associated with ingestion of high-potency sweeteners.

Comparison of inhibitory effects of the proton pump-inhibiting drugs omeprazole, esomeprazole, lansoprazole, pantoprazole, and rabeprazole on human cytochrome P450 activities.

PubMed

Li, Xue-Qing; Andersson, Tommy B; Ahlström, Marie; Weidolf, Lars

2004-08-01

The human clearance of proton pump inhibitors (PPIs) of the substituted benzimidazole class is conducted primarily by the hepatic cytochrome P450 (P450) system. To compare the potency and specificity of the currently used PPIs (i.e., omeprazole, esomeprazole, lansoprazole, pantoprazole, and rabeprazole) as inhibitors of four cytochrome P450 enzymes (CYP2C9, 2C19, 2D6, and 3A4), we performed in vitro studies using human liver microsomal preparations and recombinant CYP2C19. Sample analysis was done using selected reaction monitoring liquid chromatography/tandem mass spectometry. With several systems for CYP2C19 activity (two marker reactions, S-mephenytoin 4'-hydroxylation and R-omeprazole 5-hydroxylation, tested in either human liver microsomes or recombinant CYP2C19), the five PPIs showed competitive inhibition of CYP2C19 activity with K(i) of 0.4 to 1.5 microM for lansoprazole, 2 to 6 microM for omeprazole, approximately 8 microM for esomeprazole, 14 to 69 microM for pantoprazole, and 17 to 21 microM for rabeprazole. Pantoprazole was a competitive inhibitor of both CYP2C9-catalyzed diclofenac 4'-hydroxylation and CYP3A4-catalyzed midazolam 1'-hydroxylation (K(i) of 6 and 22 microM, respectively), which were at least 2 times more potent than the other PPIs. All PPIs were poor inhibitors of CYP2D6-mediated bufuralol 1'-hydroxylation with IC(50) > 200 microM. The inhibitory potency of a nonenzymatically formed product of rabeprazole, rabeprazole thioether, was also investigated and showed potent, competitive inhibition with K(i) values of 6 microM for CYP2C9, 2 to 8 microM for CYP2C19, 12 microM for CYP2D6, and 15 microM for CYP3A4. The inhibitory potency of R-omeprazole on the four studied P450 enzymes was also studied and showed higher inhibitory potency than its S-isomer on CYP2C9 and 2C19 activities. Our data suggest that, although the inhibitory profiles of the five studied PPIs were similar, lansoprazole and pantoprazole are the most potent in vitro inhibitors of CYP2C19 and CYP2C9, respectively. Esomeprazole showed less inhibitory potency compared with omeprazole and its R-enantiomer. The inhibitory potency of rabeprazole was relatively lower than the other PPIs, but its thioether analog showed potent inhibition on the P450 enzymes investigated, which may be clinically significant.

Potent and efficacious inhibition of CXCR2 signaling by biparatopic nanobodies combining two distinct modes of action.

PubMed

Bradley, M E; Dombrecht, B; Manini, J; Willis, J; Vlerick, D; De Taeye, S; Van den Heede, K; Roobrouck, A; Grot, E; Kent, T C; Laeremans, T; Steffensen, S; Van Heeke, G; Brown, Z; Charlton, S J; Cromie, K D

2015-02-01

Chemokines and chemokine receptors are key modulators in inflammatory diseases and malignancies. Here, we describe the identification and pharmacologic characterization of nanobodies selectively blocking CXCR2, the most promiscuous of all chemokine receptors. Two classes of selective monovalent nanobodies were identified, and detailed epitope mapping showed that these bind to distinct, nonoverlapping epitopes on the CXCR2 receptor. The N-terminal-binding or class 1 monovalent nanobodies possessed potencies in the single-digit nanomolar range but lacked complete efficacy at high agonist concentrations. In contrast, the extracellular loop-binding or class 2 monovalent nanobodies were of lower potency but were more efficacious and competitively inhibited the CXCR2-mediated functional response in both recombinant and neutrophil in vitro assays. In addition to blocking CXCR2 signaling mediated by CXCL1 (growth-related oncogene α) and CXCL8 (interleukin-8), both classes of nanobodies displayed inverse agonist behavior. Bivalent and biparatopic nanobodies were generated, respectively combining nanobodies from the same or different classes via glycine/serine linkers. Interestingly, receptor mutation and competition studies demonstrated that the biparatopic nanobodies were able to avidly bind epitopes within one or across two CXCR2 receptor molecules. Most importantly, the biparatopic nanobodies were superior over their monovalent and bivalent counterparts in terms of potency and efficacy. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

Improvement of kynurenine aminotransferase-II inhibitors guided by mimicking sulfate esters.

PubMed

Jayawickrama, Gayan S; Nematollahi, Alireza; Sun, Guanchen; Church, William Bret

2018-01-01

The mammalian kynurenine aminotransferase (KAT) enzymes are a family of related isoforms that are pyridoxal 5'-phosphate-dependent, responsible for the irreversible transamination of kynurenine to kynurenic acid. Kynurenic acid is implicated in human diseases such as schizophrenia where it is found in elevated levels and consequently KAT-II, as the isoform predominantly responsible for kynurenic acid production in the brain, has been targeted for the development of specific inhibitors. One class of compounds that have also shown inhibitory activity towards the KAT enzymes are estrogens and their sulfate esters. Estradiol disulfate in particular is very strongly inhibitory and it appears that the 17-sulfate makes a significant contribution to its potency. The work here demonstrates that the effect of this moiety can be mirrored in existing KAT-II inhibitors, from the development of two novel inhibitors, JN-01 and JN-02. Both inhibitors were based on NS-1502 (IC50: 315 μM), but the deliberate placement of a sulfonamide group significantly improved the potency of JN-01 (IC50: 73.8 μM) and JN-02 (IC50: 112.8 μM) in comparison to the parent compound. This 3-4 fold increase in potency shows the potential of these moieties to be accommodated in the KAT-II active site and the effect they can have on improving inhibitors, and the environments in the KAT-II have been suitably modelled using docking calculations.

In silico optimization of a fragment-based hit yields biologically active, high-efficiency inhibitors for glutamate racemase.

PubMed

Whalen, Katie L; Chau, Anthony C; Spies, M Ashley

2013-10-01

A novel lead compound for inhibition of the antibacterial drug target, glutamate racemase (GR), was optimized for both ligand efficiency and lipophilic efficiency. A previously developed hybrid molecular dynamics-docking and scoring scheme, FERM-SMD, was used to predict relative potencies of potential derivatives prior to chemical synthesis. This scheme was successful in distinguishing between high- and low-affinity binders with minimal experimental structural information, saving time and resources in the process. In vitro potency was increased approximately fourfold against GR from the model organism, B. subtilis. Lead derivatives show two- to fourfold increased antimicrobial potency over the parent scaffold. In addition, specificity toward B. subtilis over E. coli and S. aureus depends on the substituent added to the parent scaffold. Finally, insight was gained into the capacity for these compounds to reach the target enzyme in vivo using a bacterial cell wall lysis assay. The outcome of this study is a novel small-molecule inhibitor of GR with the following characteristics: Ki=2.5 μM, LE=0.45 kcal mol(-1) atom(-1), LiPE=6.0, MIC50=260 μg mL(-1) against B. subtilis, EC50, lysis=520 μg mL(-1) against B. subtilis. Copyright © 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of the aqueous extract of the root of Aristolochia indica: evaluation of its traditional use as an antidote for snake bites.

PubMed

Bhattacharjee, Payel; Bhattacharyya, Debasish

2013-01-09

The aqueous extract of the roots of Aristolochia indica is used as a decoction for the ailment of a number of diseases including snake bite treatment. Though the alcoholic extract of the different parts of the plant are well studied, information on the aqueous extract is limited. We have estimated aristolochic acid, different enzymes, enzyme inhibitors and anti-snake venom potency of its root extract. Reverse phase-HPLC was used to quantify aristolochic acid. Zymography, DQ-gelatin assay and atomic force microscopy were done to demonstrate gelatinase and collagenase activities of the extract. SDS-PAGE followed by MS/MS analysis revealed the identity of major protein components. Toxicity of the extract was estimated on animal model. Interaction of the extract with Russell's viper venom components was followed by Rayleigh scattering and enzyme assay. The aristolochic acid content of the root extract is 3.08 ± 1.88 × 10(-3)mg/ml. The extract possesses strong gelatinolytic, collagenase, peroxidase and nuclease activities together with l-amino acid oxidase and protease inhibitory potencies. Partial proteomic studies indicated presence of starch branching enzymes as major protein constituent of the extract. The extract did not show any acute and sub-chronic toxicity in animals at lower doses, but high dose causes liver and kidney damage. The extract elongated duration of survival of animals after application of Russell's viper venom. Considering the low aristolochic acid content of the extract, its consumption for a short time at moderate dose does not appear to cause serious toxicity. Strong inhibition of l-amino acid oxidase may give partial relief from snake bite after topical application of the extract. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Vitamin A and C compounds permitted in supplements differ in their abilities to affect cell viability, DNA and the DNA nucleoside deoxyguanosine.

PubMed

Bergström, Therese; Bergman, Jan; Möller, Lennart

2011-11-01

In accordance with the European Parliament and Council's directive, vitamin A and C supplements can include any of four (vitamin A) or five (vitamin C) specified compounds. This study focuses on these compounds and compares their abilities to affect the DNA and viability of cells in culture, but also their potencies to chemically oxidise the DNA nucleoside deoxyguanosine (dG). To study the vitamins' strict chemical oxidation potencies, dG was exposed to vitamin solution and the amount of the oxidation product 8'-hydroxydeoxyguanosine (8-oxodG) formed was estimated using a high-performance liquid chromatography system with electrochemical and ultraviolet detection. The vitamin's ability to cause DNA damage to promyelocytic leukaemia cells (HL-60), as detected by strand breaks, alkaline labile sites and formamido pyrimidine DNA glycosylase (FPG)-sensitive sites was, after vitamin exposure, measured using the comet assay and cytotoxicity was estimated using trypan blue staining. The results highlight that vitamin A and C compounds found in supplements do have different properties, chemically as well as in a cellular system. Among the vitamin C compounds, ascorbic acid, sodium ascorbate and calcium ascorbate stood out causing both oxidation to dG and cytotoxicity to cells. The vitamin A compounds retinol, retinyl acetate and retinal (a breakdown product found in vivo) caused oxidation of dG, while retinal was the only compound causing cytotoxicity, giving rise to an almost complete cell death. β-carotene caused, as the only vitamin compound, a small increase in FPG-sensitive sites. It is concluded that even though the compounds are found under the same name (vitamin A or C), they do have different properties linked to oxidation, cytotoxicity and DNA damage.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soileau, S.D.

Chlordecone (CHLO, 1-30 uM) and chlordecone alcohol (CHLO ALC, 1-23 uM) altered the permeability of isolated ovine erythrocytes (OE) as evidenced by a concentration- and time-dependent induction of K/sup +/ efflux and hemolysis. Hemolysis, but no K/sup +/ efflux, was markedly delayed when OE were suspended in isotonic sucrose. Low concentrations of both compounds (1-4 uM) protected OE against hypotonic hemolysis. Neither CHLO (30 uM) nor CHLO ALC (23 uM) induced the release of trapped K/sup +/ from KSCN-loaded, OE-lipid, unilamellar liposomes. CHLO- and CHLO ACL-induced hemolysis and K/sup +/ efflux were dependent upon the pH of the external media.more » CHLO ALC-induced K/sup +/ efflux and hemolysis showed a slight pH dependence, with increased potency of the compound detected over the pH range 8.3-9.4 CHLO ALC-induced protection against hypotonic hemolysis was pH independent. The potency of CHLO in all three assays decreased as the pH was raised from 6.4 to 9.4. (/sup 14/C)-CHLO and (/sup 14/C)-CHLO ALC binding to OE and OE membranes was pH independent. However, the binding of (/sup 14/C)-CHLO to polypropylene and glass was pH dependent. (/sup 14/C)-CHLO binding to polypropylene and glass decreased from pH 6.4 to pH 10.4. The pKa of CHLO was estimated to be 8.9. After the CHLO results were corrected for the fraction of CHLO present in the unionized form, it was estimated the ionized CHLO possessed 1/3 to 1/20 of the activity of the unionized species.« less

Subliminal Affect Valence Words Change Conscious Mood Potency but Not Valence: Is This Evidence for Unconscious Valence Affect?

PubMed Central

Shevrin, Howard; Panksepp, Jaak; Brakel, Linda A. W.; Snodgrass, Michael

2012-01-01

Whether or not affect can be unconscious remains controversial. Research claiming to demonstrate unconscious affect fails to establish clearly unconscious stimulus conditions. The few investigations that have established unconscious conditions fail to rule out conscious affect changes. We report two studies in which unconscious stimulus conditions were met and conscious mood changes measured. The subliminal stimuli were positive and negative affect words presented at the objective detection threshold; conscious mood changes were measured with standard manikin valence, potency, and arousal scales. We found and replicated that unconscious emotional stimuli produced conscious mood changes on the potency scale but not on the valence scale. Were positive and negative affects aroused unconsciously, but reflected consciously in potency changes? Or were the valence words unconscious cognitive causes of conscious mood changes being activated without unconscious affect? A thought experiment is offered as a way to resolve this dilemma. PMID:24961258

Study on potency of municipal solid waste conversion into renewable energy by thermal incineration and bioconversion: case study of Medan city

NASA Astrophysics Data System (ADS)

Sarah, Maya; Misran, Erni

2018-03-01

Municipal solid waste (MSW) in Medan City is facing problems either with the quantity and management of MSW. Local authority only dumped approximately 73.9% MSW in the landfill over the years. Spontaneous phenomena of methane formation in dumping site indicates the potency of MSW conversion into energy by biochemical conversion. On the contrary, the presence of plastics, woods, papers, etc. in the MSW show the potency of MSW to be treated by thermal conversion. Both thermal incineration and anaerobic digestion may convert MSW Medan City into energy. This study evaluates potency of MSW conversion into renewable energy using proximate and ultimate analysis. Overall, MSW of Medan City has the opportunities to be converted into energy by both thermal and biochemical conversion with a special requirement such as pre-dry the MSW prior incineration process and degrade organic MSW in a bioreactor.

Unpacking Trauma Exposure Risk Factors and Differential Pathways of Influence: Predicting Postwar Mental Distress in Bosnian Adolescents

ERIC Educational Resources Information Center

Layne, Christopher M.; Olsen, Joseph A.; Baker, Aaron; Legerski, John-Paul; Isakson, Brian; Pasalic, Alma; Durakovic-Belko, Elvira; Dapo, Nermin; Campara, Nihada; Arslanagic, Berina; Saltzman, William R.; Pynoos, Robert S.

2010-01-01

Methods are needed for quantifying the potency and differential effects of risk factors to identify at-risk groups for theory building and intervention. Traditional methods for constructing war exposure measures are poorly suited to "unpack" differential relations between specific types of exposure and specific outcomes. This study of…

New applications in EPA’s ECOTOX Knowledge System: Assimilating relative potencies of metals across chemical and biological species from literature-based toxicity effects data.

EPA Science Inventory

Toxicity of metals in field settings can vary widely among ionic chemical species and across biological receptors. Thus, a challenge often found in developing TRVs for the risk assessment of metals is identifying the most appropriate metal and biological species combinations for...

MOLECULAR STRUCTURAL FACTORS IN COMPETITIVE INHIBITION OF SUGAR TRANSPORT

DOE Office of Scientific and Technical Information (OSTI.GOV)

LeFevre, P.G.

1959-07-10

The high potency of phloretin as a competitive inhibitor of the human red cell's monosaccharide transport system is not shared by any of several molecular fragments of phloretin, but is duplicated in certain artificial estrogens resembling phloretin in respect to the spacing between terminal phenolic---OH groups. Related molecules which are slightly less extendible are comparatively inactive. (auth)

The Metabolites of Fentanyl and its Derivatives

DTIC Science & Technology

1988-09-01

TECHNIQUES ..... ........... 22 4.1 Stable Isotopes .... ............... .... 22 4.2 Radioisotope Tracers ... ............. .... 23 4.3 Radioimmunoassay...50 (relative to morphine).1 These properties have occasioned its popularity in surgical analgesia, especially when combined with a powerful ...studies by Janssen and coworkers, 5 carfentanil is one of the most powerful , achiral fentanyls. In addition to high potency, cis-3-methylfentanyl,5