Similar Mode Of Action Research Articles

Tratamento do bagaço de cana-de-açúcar para alimentação de ruminantes

Objetivou-se revisar o conhecimento sobre o tratamento do bagaço de cana-de-açúcar para a alimentação de ruminantes. A produção de bagaço in natura de cana-de-açúcar no Brasil é de aproximadamente 192,63 milhões de toneladas, representando uma fonte de alimento abundante para a alimentação animal. Este alimento é caracterizado como uma fonte de fibra íntegra, composto basicamente pelos componentes da parede celular (hemicelulose, celulose e lignina), sendo de baixo aproveitamento pelos ruminantes. Apesar disso, o bagaço in natura pode ser amplamente utilizado em dietas com elevada proporção de concentrado para ruminantes, compondo entre 10 e 20 % da matéria seca das dietas, sem grandes prejuízos sobre o desempenho animal. O tratamento por vapor e pressão reduz componentes da parede celular, aumentando a digestibilidade do bagaço da cana-de-açúcar. No entanto, este tratamento reduz o pH do bagaço, o que exige a utilização de tamponantes nas dietas para impedir a redução da digestibilidade da fibra. Em virtude do baixo estímulo à ruminação, o bagaço tratado por pressão e vapor deve ser utilizado juntamente com uma fonte de fibra integra o que possibilita o aumento da utilização do bagaço da cana-de-açúcar na dieta. Os tratamentos químicos com hidróxido de sódio, óxido de cálcio ou hidróxido de cálcio apresenta similar modo de ação, que culmina na redução da fibra em detergente neutro do bagaço da cana-de-açúcar. Apesar de mais eficiente, o tratamento com hidróxido de sódio é de difícil manipulação e pode gerar danos ao meio ambiente. A utilização de cales microprocessadas é de mais fácil manipulação e menos danosas ao meio ambiente. O tratamento com produtos alcalinos reduz o custo em relação ao tratamento com pressão e vapor. O tratamento com amônia anidra e uréia melhora o valor nutritivo pelo enriquecimento do bagaço com nitrogênio não proteico. Os tratamentos biológicos possibilitam a deslignificação do bagaço da cana-de-açúcar, aumentando a digestibilidade e o conteúdo proteico. Apesar disso, estes tratamentos não foram adaptados às condições de campo, o que dificulta sua utilização. O uso do bagaço da cana-de-açúcar na alimentação de ruminantes, independente do tratamento utilizado antes de seu fornecimento (físico, químico ou biológico), deve estar associado à quantidade de concentrado que possibilite a complementação dos nutrientes da dieta e o atendimento das exigências nutricionais dos animais.

Comparative Genome Analysis Provides Insights into the Pathogenicity of Flavobacterium psychrophilum.

Flavobacterium psychrophilum is a fish pathogen in salmonid aquaculture worldwide that causes cold water disease (CWD) and rainbow trout fry syndrome (RTFS). Comparative genome analyses of 11 F. psychrophilum isolates representing temporally and geographically distant populations were used to describe the F. psychrophilum pan-genome and to examine virulence factors, prophages, CRISPR arrays, and genomic islands present in the genomes. Analysis of the genomic DNA sequences were complemented with selected phenotypic characteristics of the strains. The pan genome analysis showed that F. psychrophilum could hold at least 3373 genes, while the core genome contained 1743 genes. On average, 67 new genes were detected for every new genome added to the analysis, indicating that F. psychrophilum possesses an open pan genome. The putative virulence factors were equally distributed among isolates, independent of geographic location, year of isolation and source of isolates. Only one prophage-related sequence was found which corresponded to the previously described prophage 6H, and appeared in 5 out of 11 isolates. CRISPR array analysis revealed two different loci with dissimilar spacer content, which only matched one sequence in the database, the temperate bacteriophage 6H. Genomic Islands (GIs) were identified in F. psychrophilum isolates 950106-1/1 and CSF 259–93, associated with toxins and antibiotic resistance. Finally, phenotypic characterization revealed a high degree of similarity among the strains with respect to biofilm formation and secretion of extracellular enzymes. Global scale dispersion of virulence factors in the genomes and the abilities for biofilm formation, hemolytic activity and secretion of extracellular enzymes among the strains suggested that F. psychrophilum isolates have a similar mode of action on adhesion, colonization and destruction of fish tissues across large spatial and temporal scales of occurrence. Overall, the genomic characterization and phenotypic properties may provide new insights to the mechanisms of pathogenicity in F. psychrophilum.

Comparing the Natural and Anthropogenic Sodium Channel Blockers Tetrodotoxin and Indoxacarb in Garter Snakes.

Synthetic chemicals, such as pesticides, are used in a variety of ways in the agricultural industry. Anthropogenic chemicals pose a unique challenge to organisms because of the lack of evolutionary history between the chemical and the organism. However, research has shown that some organisms have a resistance to these synthetic chemicals due to their evolved resistance to a natural compound with a similar structure or mode of action. Indoxacarb (INDOX) is a relatively new pesticide with a similar mode of action to that of tetrodotoxin (TTX). Tetrodotoxin is a naturally occurring toxin that is used as an antipredator defense in the rough-skinned newt (Taricha granulosa). Some populations of the common garter snake (Thamnophis sirtalis) have developed a resistance to tetrodotoxin. Here, we investigated the correlation between TTX and INDOX resistance in snakes. We hypothesized that INDOX would induce a much higher stress response than the naturally occurring TTX. We injected each snake with tetrodotoxin (1 mass-adjusted mouse unit). We did the same with mass-adjusted units of INDOX. We measured corticosterone, testosterone, and bactericidal ability. Our results show an acute stress response to INDOX, but not TTX through an elevate corticosterone and innate immune response, although there was no difference in testosterone concentration. These results suggest that, although INDOX may have a similar mechanism of action, garter snakes do not react in a similar manner as to TTX. This research gives a physiological perspective on the differences between naturally occurring compounds and synthetic compounds.

Abstract C158: A chemoproteomics strategy for target identification and lead compound optimization using chloroalkane derivatized compounds

Abstract The Identification and validation of drug targets is an industry wide challenge. There is a very clear and urgent need for technologies that can identify the interaction partners of small molecules. Chemical proteomics is one technology that has attracted attention as a solution to the drug target identification problem. Here we present a new approach utilizing a chloroalkane (CA) moiety capture handle, which can be chemically attached to small molecules to isolate their respective protein partners. In general derivatization of small molecules with the CA moiety does not impact their cell permeability and has limited impact on potency, allowing for phenotypic assays of the derivatized compound to be performed. The retention of cell permeability also allows for the capture process to be performed from live cells treated with the CA-compound. This process is also compatible with competition assays, which can be used to evaluate and compare other compounds exhibiting a similar mode of action. Here we present a study using Dasatinib-CA, a modified kinase inhibitor and potent anti-cancer drug which binds to a broad range of kinases. First we performed target enrichment experiments by incubating K562 cells with the modified Dasatinib (Dasatinib-CA). Cells were lysed and the Dasatinib-CA, together with the bound targets, was rapidly captured onto magnetic resin coated with HaloTag. Unmodified compound was used to competitively elute putative interacting proteins. Secondly using the same assay format we evaluated the relative target affinities of Dasatinib-CA versus competing molecules. Competition assays were performed by incubating multiple mixtures of Dasatinib analogues and Dasatinib-CA at varying relative concentrations. Eluted proteins were processed using SDS-PAGE and in-gel digestion. For target identification experiments peptides were analyzed using label free mass spectrometry. For the competition assays digested material was labeled with Tandem Mass Tags (TMT) 10plex reagents. Peptides were analyzed using nanoscale LC-MS/MS coupled with a Q Exactive mass spectrometer (Thermo). Protein identification and quantitation was performed with MaxQuant (MaxQuant.org) and data validation and visualization was performed using Perseus (Perseus-framework.org). Using this approach we identified over 30 kinases, including known membrane associated and membrane protein targets. This work presented here highlights a new method for chemical proteomics and demonstrates utility of the platform to enable target identification and to evaluate competitor molecules. Citation Format: Michael Ford, Richard Jones, Ravi Amunugama, Danette Daniels, Rachel Ohana, Sergiy Levin, Thomas Kirkland, Marjeta Urh, Keith Wood. A chemoproteomics strategy for target identification and lead compound optimization using chloroalkane derivatized compounds. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C158.

Multiple exposures to indoor contaminants: Derivation of benchmark doses and relative potency factors based on male reprotoxic effects

Semi-Volatile Organic Compounds (SVOCs) are commonly present in dwellings and several are suspected of having effects on male reproductive function mediated by an endocrine disruption mode of action. To improve knowledge of the health impact of these compounds, cumulative toxicity indicators are needed. This work derives Benchmark Doses (BMD) and Relative Potency Factors (RPF) for SVOCs acting on the male reproductive system through the same mode of action.We included SVOCs fulfilling the following conditions: detection frequency (>10%) in French dwellings, availability of data on the mechanism/mode of action for male reproductive toxicity, and availability of comparable dose-response relationships.Of 58 SVOCs selected, 18 induce a decrease in serum testosterone levels. Six have sufficient and comparable data to derive BMDs based on 10 or 50% of the response. The SVOCs inducing the largest decrease in serum testosterone concentration are: for 10%, bisphenol A (BMD10 = 7.72E-07 mg/kg bw/d; RPF10 = 7,033,679); for 50%, benzo[a]pyrene (BMD50 = 0.030 mg/kg bw/d; RPF50 = 1630), and the one inducing the smallest one is benzyl butyl phthalate (RPF10 and RPF50 = 0.095).This approach encompasses contaminants from diverse chemical families acting through similar modes of action, and makes possible a cumulative risk assessment in indoor environments. The main limitation remains the lack of comparable toxicological data.

Abstract 751: In vitro activity of dianhydrogalactitol alone or with platinum drugs in the treatment of non-small cell lung cancer

Abstract The median overall survival time for patients with stage IV non-small cell lung cancer (NSCLC) is 4 months, and 1- and 5-year survival is less than 16% and 2%, respectively. NSCLC is usually treated with surgery followed by treatment with either Tyrosine Kinase Inhibitors (TKIs) or platinum-based regimens. Unfortunately, TKI resistance has emerged as a significant unmet medical need, and long-term prognosis with platinum-based therapies is poor. Dianhydrogalactitol (VAL-083) is a structurally unique bi-functional alkylating agent mediating interstrand DNA crosslinks at N7 of guanine. It has previously demonstrated activity against NSCLC in preclinical and clinical trials, and is approved for treatment of lung cancer in China, suggesting that it may be a therapeutic option for drug-resistant NSCLC. However, the underlying basis for its activity remains unclear. We thus aimed to investigate in vitro i) the role of p53 status in the activity of VAL-083, ii) VAL-083 activity in comparison to cisplatin and oxaliplatin, and iii) the combination of VAL-083 with cisplatin or oxaliplatin. The dependence on p53 status was investigated in isogenic models with (HCT-116p53-/-) or without (HCT-116p53+/+) p53 knockout. The cytotoxic activity of VAL-083 was tested in a panel of 9 human NSCLC cell lines, of which 4 were wild-type (wt) p53, 4 were mutant p53 and 1 was null for p53. The potential for combination was investigated by determining superadditivity and assessing synergy using the criteria of combination index (CI) of <1, obtained by following the Compusyn constant-dose ratio protocol. Cytotoxicty in all cases was monitored on day 5 with the MTT assay. Studies in HCT-116 models demonstrated that loss of p53 increased resistance to cisplatin and oxaliplatin by 3- and 6-fold, respectively, whereas resistance to VAL-083 was <2-fold. As single agents, VAL-083, cisplatin and oxaliplatin displayed cytotoxic activity in all 9 NSCLC cell lines to varying degrees, with H460 being the most sensitive to the three agents (IC50 < 0.5 uM). The IC50 in the other cell lines ranged from 0.9 to 6.1 μM, 0.5 to 2.2 μM and 0.6 to 2.6 μM for VAL-083, cisplatin and oxaliplatin, respectively, and there was no overt difference in drug sensitivity between the wt and mutant/null p53 group. This suggests that either wt p53 is not activated and/or other genetic alterations attenuate cytotoxic activities. If the agents have similar mode of action, then combinations may only demonstrate cytotoxic additivity. However, the combination of VAL-083 with cisplatin or oxaliplatin in the A549 NSCLC model, demonstrated significant superadditivity (p<0.05) and synergism (CI < 1) for both combinations. This strongly favors non-overlapping mechanism of action between the platinum drugs and VAL-083. In conclusion, VAL-083 is less dependent on p53 for its activity, and demonstrates superadditivity/synergy against NSCLC cells when combined with either cisplatin or oxaliplatin. Citation Format: Anne Steino, Guangan He, Jeffrey A. Bacha, Sarath Kanekal, Dennis M. Brown, Zahid H. Siddik. In vitro activity of dianhydrogalactitol alone or with platinum drugs in the treatment of non-small cell lung cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 751. doi:10.1158/1538-7445.AM2015-751

Detoxification mechanisms of honey bees (Apis mellifera) resulting in tolerance of dietary nicotine.

Insecticides are thought to be among the major factors contributing to current declines in bee populations. However, detoxification mechanisms in healthy, unstressed honey bees are poorly characterised. Alkaloids are naturally encountered in pollen and nectar, and we used nicotine as a model compound to identify the mechanisms involved in detoxification processes in honey bees. Nicotine and neonicotinoids have similar modes of action in insects. Our metabolomic and proteomic analyses show active detoxification of nicotine in bees, associated with increased energetic investment and also antioxidant and heat shock responses. The increased energetic investment is significant in view of the interactions of pesticides with diseases such as Nosema spp which cause energetic stress and possible malnutrition. Understanding how healthy honey bees process dietary toxins under unstressed conditions will help clarify how pesticides, alone or in synergy with other stress factors, lead to declines in bee vitality.

A Defensin from the Model Beetle Tribolium castaneum Acts Synergistically with Telavancin and Daptomycin against Multidrug Resistant Staphylococcus aureus.

The red flour beetle Tribolium castaneum is a common insect pest and has been established as a model beetle to study insect development and immunity. This study demonstrates that defensin 1 from T. castaneum displays in vitro and in vivo antimicrobial activity against drug resistant Staphylococcus aureus strains. The minimum inhibitory concentration (MIC) of defensin 1 against 11 reference and clinical staphylococcal isolates was between 16–64 μg/ml. The putative mode of action of the defensin peptide is disruption of the bacterial cell membrane. The antibacterial activity of defensin 1 was attenuated by salt concentrations of 1.56 mM and 25 mM for NaCl and CaCl2 respectively. Treatment of defensin 1 with the reducing agent dithiothreitol (DTT) at concentrations 1.56 to 3.13 mM abolished the antimicrobial activity of the peptide. In the presence of subinhibitory concentrations of antibiotics that also target the bacterial cell envelope such as telavancin and daptomycin, the MIC of the peptide was as low as 1 μg/ml. Moreover, when tested against an S. aureus strain that was defective in D-alanylation of the cell wall, the MIC of the peptide was 0.5 μg/ml. Defensin 1 exhibited no toxicity against human erythrocytes even at 400 μg/ml. The in vivo activity of the peptide was validated in a Caenorhabditis elegans-MRSA liquid infection assay. These results suggest that defensin 1 behaves similarly to other cationic AMPs in its mode of action against S. aureus and that the activity of the peptide can be enhanced in combination with other antibiotics with similar modes of action or with compounds that have the ability to decrease D-alanylation of the bacterial cell wall.

Profiling of the effects of antifungal agents on yeast cells based on morphometric analysis.

The incidence of fungal infection and evolution of multidrug resistance have increased the need for new antifungal agents. To gain further insight into the development of antifungal drugs, the phenotypic profiles of currently available antifungal agents of three classes-ergosterol, cell wall and nucleic acid biosynthesis inhibitors-were investigated using yeast morphology as a chemogenomic signature. The comparison of drug-induced morphological changes with the deletion of 4718 non-essential genes not only confirmed the mode of action of the drugs but also revealed an unexpected connection among ergosterol, vacuolar proton-transporting V-type ATPase and cell-wall-targeting drugs. To improve, simplify and accelerate drug development, we developed a systematic classifier that sorts a newly discovered compound into a class with a similar mode of action without any mutant information. Using well-characterized agents as target unknown compounds, this method successfully categorized these compounds into their respective classes. Based on our data, we suggest that morphological profiling can be used to develop novel antifungal drugs.

140 Towards the clinical application of anti-pseudomonal bacteriophages: Activity is retained following nebulisation with a range of commercially available nebuliser systems

Objectives We have recently established efficacy of nasally-inhaled phage against P. aeruginosa in a murine model with reduced infective burden and inflammatory response (2013 ECFC Abstract 17.3). The aim of this study was to assess phage activity and titre after exposure to nebuliser systems more applicable to clinical use. Methods Four different phage (1–4) were nebulised through Pari LC Plus (LCP), Aeroeclipse II (AE) and eFlow Rapid for up to 15 min. Phage were collected downstream and titres quantified by assessing efficacy on standard plaque assay. Results were compared with phage exposed to non-functioning nebuliser chambers. Results All phage retained efficacy post-nebulisation. Nebuliser type affected recovered titres: •LCP caused significant decrease in titres of phage 1 and 2 within 5 min and phage 3 within 15 min (p •AE, despite similar mode of action to LCP, was not as detrimental to titres. Decrease in phage 1 titre was seen within 15 min, phage 2 within 10 min (p 0.05). •eFlow does not continuously nebulise and recirculate phage, hence changes in titre over time were not recorded. No titre decreases were observed at end of nebulisation (p> 0.05). •Morphology may play a role in maintenance of phage titre post-nebulisation (1 and 2 myoviridae, 3 and 4 podoviridae). Conclusions Phage efficacy was retained after nebulisation though titres dropped, greatest for LCP and least for eFlow (which fell within variability of the methodology (0.5 log)). We confirm that phage can survive nebulisation and that this mode of administration may therefore be appropriate for future clinical trials.

Improving environmental risk assessment of human pharmaceuticals.

This paper presents 10 recommendations for improving the European Medicines Agency's guidance for environmental risk assessment of human pharmaceutical products. The recommendations are based on up-to-date, available science in combination with experiences from other chemical frameworks such as the REACH-legislation for industrial chemicals. The recommendations concern: expanding the scope of the current guideline; requirements to assess the risk for development of antibiotic resistance; jointly performed assessments; refinement of the test proposal; mixture toxicity assessments on active pharmaceutical ingredients with similar modes of action; use of all available ecotoxicity studies; mandatory reviews; increased transparency; inclusion of emission data from production; and a risk management option. We believe that implementation of our recommendations would strengthen the protection of the environment and be beneficial to society. Legislation and guidance documents need to be updated at regular intervals in order to incorporate new knowledge from the scientific community. This is particularly important for regulatory documents concerning pharmaceuticals in the environment since this is a research field that has been growing substantially in the last decades.

The potential anti-androgenic effect of agricultural pesticides used in the Western Cape: In vitro investigation of mixture effects

Although it is known that environmental chemicals can affect the oestrogenic system, far less attention has been paid to chemicals interacting with the androgen receptor (AR). Pesticides, particularly fungicides, have been shown to competitively bind or affect expression of the AR in an inhibiting manner. Few studies have addressed anti-androgenic effects of agrochemical use in South Africa. The aim of this study was to screen for the ability of commonly-used pesticides (mostly fungicides) in Western Cape agricultural areas to alter the binding of an androgen (DHT) to the human AR (hAR) using a recombinant yeast androgen screen (YAS), and also to test the additivity mixture interaction hypothesis when commonly-used pesticides with similar modes of action (MOAs) are exposed in mixture. Fungicides vinclozolin, folpet, procymidone, dimethomorph, fenarimol, mancozeb, and the insecticide chlorpyrifos, all independently antagonised the binding of the androgen dihydrotestosterone (DHT) to the AR in a dose-dependent manner. The fungicide mancozeb was found to be the most potent anti-androgen in the assay. Binary, equimolar mixtures of the pesticides also antagonised the binding of DHT to the AR, but at lower IC 50 concentration potencies relative to their individual counterparts. The mixtures of the majority of the selected pesticides did not conform to the expected additive mixture interaction. Only the mixture between dimethomorph and mancozeb showed an additive mixture response at IC 50 concentrations, and, therefore, revealed a more severe AR antagonistic effect compared to their individual counterparts. This study confirmed that pesticides regularly used in agriculture inhibit the binding of androgens to the AR, but when in mixture do not always conform to the predictive addition mixture response model. Also, high relative potencies of individual chemicals in the assay were suppressed when combined with less potent chemicals, showing that the potent chemicals may not be granted access to bind with the AR when exposed in mixture. Keywords : androgen receptor, anti-androgen, fungicides, mixtures

Basic principles of toxicological evaluation of mixtures

The vast majority of toxicity studies and risk assessments deals with single chemicals. In reality, however, humans are exposed simultaneously to a large number of chemicals, indicating that exposure assessment and safety evaluation should focus on mixtures rather than on single chemicals. This review on the toxicology of chemical mixtures covers widely varying issues, ranging from the basic concepts and terminology of joint action and interaction of chemicals to different designs for studying the toxicity of mixtures. Literature data indicate that exposure to mixtures which contain low levels of chemicals, levels lower than their no observed adverse effect levels (NOAELs), can exert toxic effects whether their components have similar modes of action or not. Different approaches and examples of studies on priority real-life mixtures, strategy and guidelines for mixture risk assessment as well as challenges ahead are also presented.

In Vivo Antidiabetic Activity of the Aqueous Leaf Extract of Croton macrostachyus in Alloxan Induced Diabetic Mice

The folklore reports from traditional medical practitioners that Croton macrostachyus has bioactivity against several diseases including diabetes mellitus have not been scientifically evaluated. The aim of this study was to determine the in vivo hypoglycemic activity of aqueous leaf extracts of this plant in male swiss white albino mice. Aqueous leaf extract of Croton macrostachyus was intraperitoneally and orally administered to alloxan (180.9 mg/ kg; intraperitoneally)-induced diabetic mice at different doses of 25 mg/kgbwt, 48.4 mg/kgbwt, 93.5 mg/kgbwt, 180.9 mg/kgbwt and 350 mg/kgbwt and the effects on blood glucose levels investigated. The treatments effects were compared with three controls (normal, diabetic and diabetic treated with a standard antidiabetic drugs (insulin administered intraperitoneally at 1 IU/kg body weight in 0.1 ml physiological saline or glibenclamide administered orally at 3 mg/kg body weight in 0.1 ml physiological saline). Phytochemical composition of the leaf extracts were qualitatively assessed using standard procedures.The diabetic control mice showed significantly (p<0.05) higher fasting blood glucose when compared with normal control mice. Treatment of diabetic mice with doses of the leaf extract resulted in significantly (p<0.05) lower levels of fasting blood glucose. The effects of the leaf extract were comparable with the conventional drugs. However, the glucose lowering potency of this plant extract was dose independent. The aqueous leaf extracts contained tannins, flavonoids, saponins, sterols, anthraquinones and alkaloids. The observed hypoglycemic activity could be associated with the phytochemicals present in this plant extract. Therefore, the results suggest that Croton macrostachyus leaf extract is a potent hypoglycemic agent and this validates their folkloric usage. Further studies to investigate the mechanism of action for hypoglycemic activity for these plant species should be done in order to explore possibilities of developing a drug that can function by similar mode of action as the plant extract.

Effects of Sitagliptin on Insulin and Glucagon Levels in Type 2 Diabetes Mellitus.

Effects of Sitagliptin on Insulin and Glucagon Levels in Type 2 Diabetes Mellitus.

The Effects of a GLP-1 Analog on Glucose Homeostasis in Type 2 Diabetes Mellitus Quantified by an Integrated Glucose Insulin Model.

In recent years, several glucagon-like peptide-1 (GLP-1)-based therapies for the treatment of type 2 diabetes mellitus (T2DM) have been developed. The aim of this work was to extend the semimechanistic integrated glucose-insulin model to include the effects of a GLP-1 analog on glucose homeostasis in T2DM patients. Data from two trials comparing the effect of steady-state liraglutide vs. placebo on the responses of postprandial glucose and insulin in T2DM patients were used for model development. The effect of liraglutide was incorporated in the model by including a stimulatory effect on insulin secretion. Furthermore, for one of the trials an inhibitory effect on glucose absorption was included to account for a delay in gastric emptying. As other GLP-1 receptor agonists have similar modes of action, it is believed that the model can also be used to describe the effect of other receptor agonists on glucose homeostasis.

Killing of staphylococci by θ-defensins involves membrane impairment and activation of autolytic enzymes.

θ-Defensins are cyclic antimicrobial peptides expressed in leukocytes of Old world monkeys. To get insight into their antibacterial mode of action, we studied the activity of RTDs (rhesus macaque θ-defensins) against staphylococci. We found that in contrast to other defensins, RTDs do not interfere with peptidoglycan biosynthesis, but rather induce bacterial lysis in staphylococci by interaction with the bacterial membrane and/or release of cell wall lytic enzymes. Potassium efflux experiments and membrane potential measurements revealed that the membrane impairment by RTDs strongly depends on the energization of the membrane. In addition, RTD treatment caused the release of Atl-derived cell wall lytic enzymes probably by interaction with membrane-bound lipoteichoic acid. Thus, the premature and uncontrolled activity of these enzymes contributes strongly to the overall killing by θ-defensins. Interestingly, a similar mode of action has been described for Pep5, an antimicrobial peptide of bacterial origin.

KATP-channels play a minor role in the protective hypoxic shut-down of cerebellar activity in eider ducks (Somateria mollissima)

Eider duck (Somateria mollissima) cerebellar neurons are highly tolerant toward hypoxia in vitro, which in part is due to a hypoxia-induced depression of their spontaneous activity. We have studied whether this response involves ATP-sensitive potassium (KATP) channels, which are known to be involved in the hypoxic/ischemic defense of mammalian neural and muscular tissues, by causing hyperpolarization and reduced ATP demand. Extracellular recordings in the Purkinje layer of isolated normoxic eider duck cerebellar slices showed that their spontaneous neuronal activity decreased significantly compared to in control slices when the KATP channel opener diazoxide (600μM) was added (F1,70=92.781, p<0.001). Adding the KATP channel blocker tolbutamide (400μM) 5min prior to diazoxide completely abolished its effect (F1,55=39.639, p<0.001), strongly suggesting that these drugs have a similar mode of action in this avian species as in mammals. The spontaneous activity of slices treated with tolbutamide in combined hypoxia/chemical anoxia (95% N2–5% CO2 and 2mM NaCN) was not significantly different from that of control slices (F1,203=0.071, p=0.791). Recovery from hypoxia/anoxia was, however, slightly but significantly weaker in tolbutamide-treated slices than in control slices (F1,137=15.539, p<0.001). We conclude that KATP channels are present in eider duck cerebellar neurons and are activated in hypoxia/anoxia, but that they do not play a key role in the protective shut-down response to hypoxia/anoxia.

Organization, teamwork, and advocacy: Important skills needed by hospice family caregivers who manage medications.

121 Background: In the home hospice setting, family caregivers (CGs) often assume medication administration responsibilities traditionally performed by licensed nurses. Little is known about how to assess and support CG medication management skills. As part of an ongoing study of nurse-caregiver interactions in home hospice, we gathered data on CG medication management needs. Methods: A longitudinal, multicenter study of home hospice nurse visits captured audiorecorded communication between nurses and CGs. Participants included patients with cancer and their self-identified CGs who were recruited upon home hospice enrollment. The current sub-study included participants aged ≥65 and their family CGs from 7 hospice agencies. Two investigators independently coded transcriptions of the first audio recorded nurse home visit using a directive content analytic approach to map conversations to a previously published, interview-derived, framework for hospice medication management by CGs. Results: A total of 18 patients (mean age 76.5 [SD 10.7], 56% female) and their CGs (mean age 59.6 [SD13.4], 78% female) were included. Content analysis revealed that CG skills needed for medication management are not limited to drug knowledge. Complicated organizational skills are needed to track medication acquisition and dosing, record the use of short- and long-acting drugs with similar modes of action, and coordinate medication administration by multiple CGs. Teamwork skills are needed to help coordinate medication prescribing between specialist, primary, and hospice physicians. CGs also need symptom management skills regarding the proper selection of medications, as well as skills to manage side effects, inadvertent errors, and possible medication related-emergencies. CGs play a vital role in patient advocacy, alerting providers to the burden and quality of life issues related to medication use, including whether medications have intended or unintended effects, or are potentially unnecessary or causing harm. Conclusions: CGs must have multiple skills to effectively manage medications in home hospice. A systematic approach and intervention is needed to support CGs’ medication management skills.

Anti-vascular endothelial growth factor therapies in ophthalmology: current use, controversies and the future.

Use of anti-vascular endothelial growth factor (VEGF) therapies was introduced for the treatment of ocular disorders in 2005. In the UK, the current licensed and NICE approved indications are for the treatment of neovascular age-related macular degeneration (nAMD), diabetic macular oedema (DMO), macular oedema secondary to a retinal vein occlusion (RVO) and choroidal neovascularization in pathological myopia. These diagnoses alone account for two-thirds of the main causes of legally registrable visual impairment and blindness. Ranibizumab (Lucentis®; Genentech/Novartis), a drug specifically designed for intraocular use, is the primary licensed medication. Controversially however, clinicians have been using an unlicensed cheaper drug, bevacizumab (Avastin®; Genentech/Roche), originally designed for systemic administration, with a similar mode of action and shown to have a similar efficacy. However, there are fears of greater side effects with bevacizumab though studies have not been sufficiently powered to show statistical difference. In the current global economic climate, anti-VEGF treatment places huge financial and logistical pressure on already strained health care systems. Bevacizumab is considerably more cost effective than ranibizumab, and thus using bevacizumab would widen access to treatment particularly in developing countries. This licensing issue also places clinicians in a difficult medico-legal position especially in Europe, where doctors are duty bound to use a licensed drug for a particular indication if this is available. As the indications of anti-VEGF therapies expand and the cost of health care provision becomes more expensive, the controversies surrounding their use will inevitably become more important.