Relative Neurotoxicity of Ivermectin and Moxidectin in Mdr1ab (?/?) Mice and Effects on Mammalian GABA(A) Channel Activity

The anthelmintics ivermectin (IVM) and moxidectin (MOX) display differences in toxicity in several host species. Entrance into the brain is restricted by the P-glycoprotein (P-gp) efflux transporter, while toxicity is mediated through the brain GABA(A) receptors. This study compared the toxicity of IVM and MOX in vivo and their interaction with GABA(A) receptors in vitro. Drug toxicity was assessed in Mdr1ab(−/−) mice P-gp-deficient after subcutaneous administration of increasing doses (0.11–2.0 and 0.23–12.9 µmol/kg for IVM and MOX in P-gp-deficient mice and half lethal doses (LD₅₀) in wild-type mice). Survival was evaluated over 14-days. In Mdr1ab(−/−) mice, LD₅₀ was 0.46 and 2.3 µmol/kg for IVM and MOX, respectively, demonstrating that MOX was less toxic than IVM. In P-gp-deficient mice, MOX had a lower brain-to-plasma concentration ratio and entered into the brain more slowly than IVM. The brain sublethal drug concentrations determined after administration of doses close to LD₅₀ were, in Mdr1ab(−/−) and wild-type mice, respectively, 270 and 210 pmol/g for IVM and 830 and 740–1380 pmol/g for MOX, indicating that higher brain concentrations are required for MOX toxicity than IVM. In rat α1β2γ2 GABA channels expressed in Xenopus oocytes, IVM and MOX were both allosteric activators of the GABA-induced response. The Hill coefficient was 1.52±0.45 for IVM and 0.34±0.56 for MOX (p<0.001), while the maximum potentiation caused by IVM and MOX relative to GABA alone was 413.7±66.1 and 257.4±40.6%, respectively (p<0.05), showing that IVM causes a greater potentiation of GABA action on this receptor. Differences in the accumulation of IVM and MOX in the brain and in the interaction of IVM and MOX with GABA(A) receptors account for differences in neurotoxicity seen in intact and Mdr1-deficient animals. These differences in neurotoxicity of IVM and MOX are important in considering their use in humans.     

Stability,Vigor, and Inherent Versatility of Novel Amino Linker and Spacer Phosphoramidites

Abstract

Novel amino linker and spacer phosphoramidites were synthesized from methoxyoxalamido (MOX) percursors possessing a secondary hydroxyl, which when phosphitylated endowed stability to the corresponding phosphoramidites. The synthetic strategy is robust, and the chemistry is reactive towards a variety of primary aliphatic diamines and amino alcohols to produce distinctly unique phosphoramidites. The selection of building blocks determines the length and physico-chemical properties of the phosphoramidite tethering arms, and the synthesis can be specifically tailored to suit individual requirement.     

Selection for anthelmintic resistance by macrocyclic lactones in Haemonchus contortus.

Two morphologically marked strains of Haemonchus contortus, CAVRS (smooth-macrocyclic lactone resistant) and McMaster (linguiform-macrocyclic lactone susceptible), were used to investigate the selection for anthelmintic resistance following exposure to ivermectin (IVM), a non-persistent anthelmintic. and a more persistent anthelmintic, oral moxidectin (MOX). Three types of selection were investigated: (1) selection of resident worms at the time of treatment (Head selection); (2) selection of incoming-larvae post-treatment (Tail selection); and (3) selection of both resident population and incoming larvae (Head + Tail selection). The experimental animals were adult sheep and lambs. In the controls where there was no anthelmintic selection, the proportion of CAVRS in the adult worm population was the same as the proportion in larvae given to both adults and lambs indicating that CAVRS and McMaster H. contortus were equally infective. There was a significant effect of anthelmintic on total worm numbers in adult sheep with MOX treated adults having less worms, but selection type was non-significant. Anthelmintic type had a significant effect on numbers of resistant worms in adult sheep with less resistant worms in the MOX treated groups, but selection type had no effect. Analysis of variance of arcsine-transformed proportions of resistant worms found that the type of anthelmintic had a highly significant effect, with MOX treated adults having a higher proportion of resistant worms, while type of selection was not significant. In the lambs, nil treated controls and IVM Head + Tail and Tail selected groups had similar geometric mean total worm burdens while Head selected had less total worms. In the MOX treated lamb groups the worm burdens were similar within selection type but less than the IVM treated groups. In the lambs, the types of selection that resulted in more resistant worms were IVM Tail, MOX Head + Tail and MOX Tail. Resistant worm numbers were similar in both adult and lamb groups with Head selection by either MOX or IVM. Moxidectin selected out higher proportions of resistant worms than did IVM in the lambs, with Tail and Head + Tail being stronger selectors than Head. Computer simulations were used to estimate the rate at which resistance developed in the field using the information generated in the present study. The anthelmintic treatments used in the simulation followed a strategic parasite control program for H. contortus in which all sheep receive three Closantel (CLS) treatments in summer. all sheep receive a broad-spectrum (BS) drench or capsule at weaning and lambs receive an additional two BS drenches insummer or no further treatment in the case of the capsule. Moxidectin, IVM-capsule and IVM were the broad spectrum anthelmintics simulated. All simulations were run four times assuming high or low efficacy against resident resistant worms and in the presence or absence of CLS resistance. The simulations indicated that the presence of CLS resistance hastened selection for macrocyclic lactone (ML) resistance. While the IVM-capsule will select most rapidly for ML resistance, IVM oral is expected to be least selective. Moxidectin treatment is intermediate, except in simulations with no CLS resistance and when MOX is assumed to be highly effective against resident ML-resistant worms, in which case MOX can be expected to select more slowly than IVM oral treatments.     

Chemiluminescence determination of moxifloxacin in pharmaceutical and biological samples based on its enhancing effect of the luminol–ferricyanide system using a microfluidic chip

A sensitive determination of a synthetic fluoroquinolone antibacterial agent, moxifloxacin (MOX), by an enhanced chemiluminescence (CL) method using a microfluidic chip is described. The microfluidic chip was fabricated by a soft‐lithographic procedure using polydimethyl siloxane (PDMS). The fabricated PDMS microfluidic chip had three‐inlet microchannels for introducing the sample, chemiluminescent reagent and oxidant, and a 500 µm wide, 250 µm deep and 82 mm long microchannel. An enhanced CL system, luminol–ferricyanide, was adopted to analyze the MOX concentration in a sample solution. CL light was emitted continuously after mixing luminol and ferricyanide in the presence of MOX on the PDMS microfluidic chip. The amount of MOX in the luminol–ferricyanide system influenced the intensity of the CL light. The linear range of MOX concentration was 0.14–55.0 ng/mL with a correlation coefficient of 0.9992. The limit of detection (LOD) and limit of quantification (LOQ) were 0.06 and 0.2 ng/mL respectively. The presented method afforded good reproducibility, with a relative standard deviation (RSD) of 1.05% for 10 ng/mL of MOX, and has been successfully applied for the determination of MOX in pharmaceutical and biological samples. Copyright © 2013 John Wiley & Sons, Ltd.     

Associations between oral hygiene habits,diet, tobacco and alcohol and risk of oral cancer: A case–control study from India

ObjectiveThis study examines the association between the incidence of oral cancer in India and oral hygiene habits, diet, chewing and smoking tobacco, and drinking alcohol. We also assessed the effects of oral hygiene habits with oral cancer risk among chewers versus never chewers.MethodsA hospital-based case–control study was conducted in Pune, India, based on face-to-face interviews, anthropometry, and intra-oral examinations conducted for 187 oral cancer cases and 240 controls.ResultsPoor oral hygiene score was associated with a significant risk of oral cancer (adjusted OR = 6.98; 95%CI 3.72–13.05). When stratified by tobacco-chewing habit, the poor oral hygiene score was a significant risk factor only among ever tobacco chewers (adjusted OR = 14.74; 95%CI 6.49–33.46) compared with never chewers (adjusted OR = 0.71; 95%CI 0.14–3.63). Dental check-ups only at the time of pain by ever-chewers with poor oral hygiene was associated with an elevated risk (adjusted OR = 4.22; 95%CI 2.44–7.29), while consumption of green, yellow, and cruciferous vegetables and citrus fruits was protective. A linear dose–response association was observed between oral cancer and chewing tobacco in terms of age at initiation, duration, and frequency of chewing per day (P < 0.001). Smoking more than 10 bidis/cigarettes per day (adjusted OR = 2.74; 95%CI 1.28–5.89) and for a duration >25 years (adjusted OR = 2.31; 95%CI 1.14–4.71) elevated the risk of oral cancer.ConclusionGood oral hygiene habits – as characterized by healthy gums, brushing more than once daily, use of toothpaste, annual dental check-ups, and a minimal number of missing teeth – can reduce the risk of oral cancer significantly. In addition to refraining from chewing/smoking tobacco, a diet adequate in fruits and vegetables may protect against the disease.     

Production of catalase-free alcohol oxidase by Hansenula polymorpha

Summary Many of the potential technical applications of alcohol oxidase (MOX; EC 1.1.3.13) are limited by the presence of high activities of catalase in the enzyme preparations. In order to circumvent laborious and costly purification or inactivation procedures, the induction of MOX in a catalase-negative mutant of Hansenula polymorpha has been studied. Emphasis was laid on the induction of activities of MOX and the dissimilatory enzymes in continuous cultures grown on various mixtures of formate/glucose and formaldehyde/glucose. In continuous cultures of the catalase-negative mutant grown on these mixtures, MOX can be induced efficiently. To obtain a stable and productive process, the ratio of the substrates is of critical importance. The optimal ratios of the mixtures for the catalase-negative strain for formate/glucose and formaldehyde/glucose were 3:1 and 1–2:1, respectively. Under identical cultivation conditions the wild-type strain showed similar induction patterns for MOX and the dissimilatory enzymes formaldehyde dehydrogenase (FaDH) and formate dehydrogenase (FoDH). The MOX levels in the catalase-negative strain were approx. 50% of those in the wild-type strain.     

Genetic relationships between two homologous goat breeds from Portugal and Brazil assessed by microsatellite markers

Twenty microsatellite markers were used to investigate genetic diversity and relationships in the Portuguese Serpentina (SERP) and the Brazilian Moxotó (MOX) goat breeds, which present a striking resemblance and are believed to have a common origin. A total of 46 animals of the SERP breed were sampled in southern Portugal, and 233 MOX goats were sampled in five different regions of Northeast Brazil. Genetic diversity was high, with a mean number of alleles of nearly 8.7 in both breeds, but expected heterozygosity and allelic richness were higher in SERP. The genetic distance between the two breeds resulted in a global F_ST of 0.16, and a strong deficit in within-breed heterozygosity was observed in MOX, mostly because of population substructuring. The estimated inbreeding was about 0.05 in SERP and ranged from 0.02 to 0.08 in the different MOX subpopulations. These subpopulations showed considerable genetic differentiation from each other, and those sampled in Paraíba and Rio Grande do Norte are the ones with a closer relationship with SERP. The analysis with STRUCTURE confirmed that some MOX subpopulations may share a common, but distant, ancestry with SERP, both having contributions from the same potential ancestral population. Other MOX subpopulations, however, are identified with ancestral populations distinct from SERP. These analyses further confirmed that, with the exception of goats from Rio Grande do Norte, the other MOX subpopulations show very little evidence of admixture among them, which may reflect the typical goat raising system in Northeast Brazil, where herds are usually kept closed and isolated, with little opportunity for gene flow among subpopulations. Our results indicate that SERP is likely a distant ancestor of MOX, but founder effects, genetic drift, selection for different environmental constraints and the possible influence of other breeds in the more recent past, probably lead to a differentiation of MOX subpopulations from their distant ancestor, as well as from each other.     

Cell wall strength of Hansenula polymorpha in continuous cultures in relation to the recovery of methanol oxidase (MOX)

Summary The changes in cell wall strength of Hansenula polymorpha have been investigated in continuous cultures with respect to the recovery of methanol oxidase (MOX). Cultures grown on several substrate mixtures that enable induction of MOX have been compared with cultures grown on methanol as the sole inducer. The effects of dilution rate (D) on lysis properties have been studied. The cell wall strength was consistently influenced by growth media and D. Media containing glycerol/methanol showed the slowest lysis kinetics, with a large fraction of non-degradable cell wall material. In continuous cultures grown on a mixture of glucose and methanol both the resistance to zymolyase and the mean cell wall thickness increased at D<0.1 h^–1. The yield of MOX by zymolyase lysis is reproducible and up to 100% higher than that of the standard ultrasonic treatment. The lysis kinetics indicated that zymolyase punctures the cell wall; since the release rate of MOX is lower than that of protein, the cell contents will leak through. At D-values>0.2 h^–1, both protein and MOX release rates increase, reflecting a change in lysis mechanism due to the increased fraction of thin daughter cells. Kinetic analysis of zymolyase lysis using both physical and enzymatic methods provides information for achieving optimal recovery of MOX.Abbreviations and symbols C _MOX MOX activity [MOX units·g X^–1] - D dilution rate [h^–1] - MOX methanol oxidase - k_c decay rate constant of A 610 nm [min^–1] - k_d decay constant of MOX activity [min^–1] - k_dis dissociation rate constant [min^–1] - k_MOX release rate constant of MOX activity [min^–1] - k_p release rate constant of protein [min^–1] - R recovery efficiency of enzyme [-] - St stability of enzyme [-]     

Novel Biotin Phosphoramidites with Super-long Tethering Arms

Abstract

A number of novel biotin phosphoramidites, possessing exceptionally long and uncharged tethering arms, were synthesized from methoxyoxalamido (MOX) and succinimido (SUC) precursors. Included among these monomers is a uridine derivative with the biotin moiety attached through the 2′-position. Some of these phosphoramidites were used to make 5′-biotinylated primers, which were applied in direct sequencing of genomic DNA and capture of Sanger fragment pools.     

Isolation of the human MOX2 homeobox gene and localization to chromosome 7p22.1–p21.3

We have isolated and characterized cDNA clones encoding a novel human homeobox gene, MOX2, the homologue of the murine mox-2 gene. The MOX2 protein contains all of the characteristic features of Mox-2 proteins of other vertebrate species, namely the homeobox, the polyhistidine stretch, and a number of potential serine/threonine phosphorylation sites. The homeodomain of MOX2 protein is identical to all other vertebrate species reported so far (rodents and amphibians). Outside the homeodomain, Mox-2 proteins share a high degree of identity, except for a few amino acid differences encountered between the human and the rodent polypeptides. A polyhistidine stretch of 12 amino acids in the N terminal region of the protein is also conserved among humans, rodents, and (only partly) amphibians. The chromosomal position of MOX2 was assigned to 7p22.1–p21.3.     

Bioconversion of methanol to formaldehyde. II. By purified methanol oxidase from modified yeast, Hansenula polymorpha

Modified methylotrophic yeast Hansenula polymorpha (HP A16) that was obtained by repressing leucine oxotrophic yeast; a wild type of Hansenula polymorpha CB4732 was used in this study. The yeast is grown with methanol, which is used as a sole carbon source, using various methanol concentrations and temperatures, and methanol oxidase (MOX) which is a key enzyme of methanol metabolism; production is maximized. Whole yeast cells were cultivated under optimized inoculation conditions; they were separated into two portions. One portion of these cells was directly used in bioconversion of methanol to formaldehyde. The second portion of the free cells was broken into pieces and a crude enzyme extract was obtained. The MOX enzyme in this extract was purified via salt precipitation, dialysis, and chromatographic methods. The purified MOX enzyme of yeast (HP A16) oxidized the methanol to formaldehyde. Optimization of bioconversion conditions was studied to reach maximum activity of enzyme. The optimum temperature and pH were found to be 35 degrees C and pH 8.0 in boric acid/NaOH buffer, and it was stable over the pH range of 6-9, at the 20 degrees C 15 min. A suitable reaction period was found as 50 min. The enzyme indicated low carbon primary alcohols (C2 to C4), as well as methanol. Initially, MOX activity increased with the increase of methanol concentration, but enzyme activity decreased. The apparent Km and Vmax values for methanol substrate of HP A16 MOX were 0.25 mM and 30 U/mg, respectively. The purified MOX enzyme was applied onto sodium dodecyl sulphate-polyacrylamide gel electrophoresis; molecular weight of the enzyme was calculated to be about 670 kDa. Each MOX enzyme is composed of eight identical subunits, each of whose molecular weight is around 82 kDa and which contain eight moles of FAD as the prosthetic group, and the pI of the natural enzyme is found to be 6.4. The purified MOX enzyme was used in the bioconversion of methanol to formaldehyde as a catalyst; this conversion was compared to the conversion percentages of whole cells in our previous article in terms of catalytic performances.     

Antitussive effect of a fixed combination of Justicia adhatoda,Echinacea purpurea and Eleutherococcus senticosus extracts in patients with acute upper respiratory tract infection: A comparative,randomized, double-blind,placebo-controlled study

BackgroundKan Jang® oral solution (KJ) is a fixed combination of aqueous ethanolic extracts of Justicia adhatoda L. leaf, Echinacea purpurea (L.) Moench root, and Eleutherococcus senticosus (Rupr. & Maxim.) Harms root. It is approved in Scandinavia as an herbal medicinal product for respiratory tract infection treatment.PurposeThe present clinical trial aimed to compare the antitussive effect of KJ with placebo (PL) and bromhexine (BH) among patients of 18–65 years old with non-complicated upper respiratory infections (URI; i.e., common cold).Study designWe performed a parallel-group, randomized, double-blinded, placebo-controlled trial in in 177 patients with acute URI over a 5 day period.MethodsWe investigated the antitussive effects of a KJ (30 ml/day; 762 mg genuine extracts with standardized contents of 0.2 mg/ml vasicine, 0.8 mg/ml chicoric acid, and 0.03 mg/ml eleutherosides B and E), bromhexine hydrochloride (24 mg/30 ml/day) and PL on cough and blood markers. The primary outcome was cough relief, which was assessed as the change of cough frequency from baseline (cough index). Secondary outcomes were safety with regards to reported adverse events (AEs) and hematological data.ResultsBoth KJ and BH relieved cough more effectively than placebo. On the third and fourth days of treatment, we observed faster improvement in the group receiving KJ compared to in the groups receiving BH (100%) or PL (100%), indicating a slightly shorter recovery time in the KJ group. KJ showed a good tolerability and safety profile.ConclusionKJ exerted significant antitussive effects in URI. The present data further support the therapeutic use of KJ in upper respiratory tract infections.     

A standardized polyphenol mixture extracted from poplar-type propolis for remission of symptoms of uncomplicated upper respiratory tract infection (URTI): A monocentric,randomized, double-blind,placebo-controlled clinical trial

BackgroundThe most common symptoms of mild upper respiratory tract infections (URTIs) are sore throat, muffled dysphonia, and swelling and redness of the throat, which result from the inflammation process following acute bacterial or viral infection.Hypothesis/purposeAs propolis is a natural resinous substance traditionally used to maintain oral cavity and upper respiratory tract health due to its antimicrobial and anti-inflammatory properties, the aim of this study is to evaluate the efficacy of an oral spray based on poplar-type propolis extract with a known and standardized polyphenol content, on the remission of the symptoms associated with mild uncomplicated URTIs.Study designA monocentric, randomized, double-blind, placebo-controlled clinical trial was performed.MethodsThis study was conducted in 122 healthy adults who had perceived mild upper respiratory tract infections. Participants, randomly assigned to receive either propolis oral spray (N = 58) or placebo (N = 64), underwent four visits (baseline = t0, after 3 days = t1 and after 5 days = t2 and after a follow-up of 15 days = t3) in an outpatient setting. Propolis oral spray total polyphenol content was 15 mg/ml. The dosage was 2-4 sprays three times/day (corresponding to 12-24 mg of polyphenols/day), for five days. The duration of the study was 8 weeks.ResultsAfter 3 days of treatment, 83% of subjects treated with propolis oral spray had remission of symptoms, while 72% of subjects in the placebo group had at least one remaining symptom. After five days, all subjects had recovered from all symptoms. This means that resolution from mild uncomplicated URTIs took place two days earlier, instead of taking place in five days as recorded in the control group. There was no relationship between the ingestion of propolis oral spray or placebo and adverse reactions.ConclusionPropolis oral spray can be used to improve both bacterial and viral uncomplicated URTI symptoms in a smaller number of days without the use of pharmacological treatment, leading to a prompt symptom resolution.     

Therapy with Zoledronic Acid, 5 Mg,for a Patient with Paget Disease of Bone

ObjectiveTo describe the effects of an infusion of zoledronic acid in a patient with Paget disease of bone (PD) who had been treated unsuccessfully with several other bisphosphonates.MethodsThe patient’s treatment history is described, and his response to various bisphosphonates, including zoledronic acid, is discussed.ResultsThe patient was a 61-year-old man when a diagnosis of PD was made on the basis of an elevated serum alkaline phosphatase (ALP) level of 391 U/L (reference range, 45 to 135). Pagetic bone changes were noted on bone scan and x-ray examinations. Treatment with etidronate had no effect on ALP levels. This intervention was followed by 2 courses of intravenous therapy with pamidronate, which decreased ALP levels by 57% and 55% without inducing a remission. Subsequent oral treatment with alendronate and then risedronate yielded unsustained biochemical remissions of 6 months each. Most recently, therapy with an infusion of 5 mg of zoledronic acid induced a remission that is thus far 20 months in duration. With this therapy, the patient has experienced no side effects, and he has noted a decrease in bone pain.ConclusionThis case study shows that a patient with PD who received successive treatments with several bisphosphonates with inadequate responses or only brief remissions was more effectively treated with a single 5-mg infusion of zoledronic acid. This patient’s therapeutic responses illustrate the relative efficacy of available bisphosphonates and the potential for longer-lasting remissions with zoledronic acid in patients with PD. (Endocr Pract. 2008;14:607-610)     

Development of a Novel Selective and Differential Medium for the Isolation of Listeria monocytogenes

A new medium (lecithin and levofloxacin [LL] medium) is described for the isolation of Listeria monocytogenes from food samples. LL medium includes lecithin from soybeans for the detection of phosphatidylinositol-specific phospholipase C (PI-PLC) and phosphatidylcholine-specific phospholipase C (PC-PLC) produced by L. monocytogenes. Levofloxacin is incorporated to inhibit the growth of microorganisms other than L. monocytogenes, especially Bacillus cereus, shown to possess PI-PLC and PC-PLC activities. L. monocyogenes produced white colonies with a halo on LL medium, whereas Listeria innocua appeared as white colonies without a halo. Levofloxacin at 0.20 mg/liter completely inhibited the growth of B. cereus, while the growth of L. monocytogenes was unaffected. In the second phase of the study, the sensitivity and the specificity of LL medium were compared to those of modified Oxford agar (MOX) and two chromogenic media (Brilliance Listeria agar and CHROMagar Listeria), using a total of 250 food samples. From 200 unspiked food samples, the specificity of LL medium (96.0%) was superior to that of MOX (72.0%) and similar to the specificities of Brilliance Listeria agar (96.5%) and CHROMagar Listeria (94.5%). From 50 spiked food samples, LL medium and CHROMagar Listeria represented the highest sensitivities (96.0%), followed by Brilliance Listeria agar (92.0%) and MOX (54.0%). Also, LL medium showed the highest confirmation rate (98.8%), followed by Brilliance Listeria agar (98.7%), CHROMagar Listeria (98.3%), and MOX (52.0%). On the basis of its good specificity and cost effectiveness, LL medium is useful for the isolation of L. monocytogenes from food samples.     

Gesture-Controlled Image Management for Operating Room: A Randomized Crossover Study to Compare Interaction Using Gestures,Mouse, and Third Person Relaying

ObjectiveIn this work, we aim at comparing formally three different interaction modes for image manipulation that are usable in a surgery setting: 1) A gesture-controlled approach using Kinect ®; 2) oral instructions to a third part dedicated to manipulate the images; and 3) direct manipulation using a mouse.Results30 physicians and senior medical students participated in the experiment. Efficiency, measured as time used to pass the scenario, was best when using the mouse (M = 109.10s, SD = 25.96), followed by gesture-controlled (M = 214.97s, SD = 46.29) and oral instructions (M = 246.33s, SD = 76.50). Satisfaction, measured by a questionnaire, was rated highest in the condition mouse (M = 6.63, SD = 0.56), followed by gesture-controlled (M = 5.77, SD = 0.93) and oral instructions (M = 4.40, SD = 1.71). Differences in efficiency and satisfaction rating were significant. No significant difference in effectiveness, measured with error rates, was found.DiscussionThe study shows with formal evaluation that the use of gestures is advantageous over instructions to a third person. In particular, the use of gestures is more efficient than verbalizing instructions. The given gestures could be learned easily and reliability of the tested gesture-control system is good.ConclusionUnder the premise that mouse cannot be used directly during surgery, gesture-controlled approaches demonstrate to be superior to oral instructions for image manipulation.     

Selection of different genotype larvae and adult worms for anthelmintic resistance by persistent and short-acting avermectin/milbemycins

To understand the factors that influence selection for anthelmintic resistance, it is necessary to examine the impact of drug treatment, particularly persistent drugs, on all phases of the worm life cycle. The efficacy of various avermectin/milbemycin anthelmintics was determined against resident worms, incoming larvae (L3) and development of eggs in faecal culture. Homozygote-resistant and maternal and paternal F1-heterozygote genotypes of Haemonchus contortus were used to infect sheep before or after treatment with ivermectin (IVM) oral, IVM capsule, moxidectin (MOX) oral or MOX injectable. Total worm count and quantitative larval culture were used to determine efficacy against parasitic and free-living stages, respectively. Selection for resistance by IVM capsules occurred at the adult and L3 stages because of poor efficacy against these stages for all resistant genotypes. However, the selective advantage of these surviving worms was reduced due to the low development of their eggs to L3 in faecal culture. For MOX, selection for resistance predominantly occurred after treatment because of high efficacy against resident adult worms of all resistant genotypes but poor efficacy against resistant L3 ingested after drug administration. The results indicated no evidence of sex-linked inheritance for IVM resistance. Mean IVM efficacies against homozygous and heterozygous resistant adult worms were not different, and IVM capsule efficacy against incoming L3 was approximately 70% for all resistant genotypes, consistent with a dominant trait. MOX was highly effective against adults of all resistant genotypes and approximately 76% effective against incoming L3 regardless of resistance genotype, also consistent with a dominant trait. These results will enable the impact of persistent drugs on worm control and anthelmintic resistance to be estimated. The results indicate that IVM capsules should not be used in populations where avermectin/milbemycin resistance is present.     

DA-1229, a novel and potent DPP4 inhibitor, improves insulin resistance and delays the onset of diabetes

AimTo characterize the pharmacodynamic profile of DA-1229, a novel dipeptidyl peptidase (DPP) 4 inhibitor.Main methodsEnzyme inhibition assays against DPP4, DPP8 and DPP9. Antidiabetic effects of DA-1229 in HF-DIO mice and young db/db mice.Key findingsDA-1229 was shown to potently inhibit the DPP4 enzyme in human and murine soluble forms and the human membrane-bound form with IC₅₀ values of 0.98, 3.59 and 1.26 nM, respectively. As a reversible and competitive inhibitor, DA-1229 was more selective to human DPP4 (6000-fold) than to human DPP8 and DPP9. DA-1229 (0.1–3 mg/kg) dose-dependently inhibited plasma DPP4 activity, leading to increased levels of plasma GLP-1 and insulin, and thereby lowering blood glucose levels in mice. In high fat diet-fed (HF) mice, a single oral dose of 100 mg/kg of DA-1229 reduced plasma DPP4 activity by over 80% during a 24 h period. Long-term treatment with DA-1229 for 8 weeks revealed significant improvements in glucose intolerance and insulin resistance, accompanied by significant body weight reduction. However, it remains unclear whether there is a direct causal relationship between DPP4 inhibition and body weight reduction. In young db/db mice, the DA-1229 treatment significantly reduced blood glucose excursions for the first 2 weeks, resulting in significantly lower levels of HbA1c at the end of the study. Furthermore, the pancreatic insulin content of the treatment group was significantly higher than that of the db/db control.SignificanceDA-1229 as a novel and selective DPP4 inhibitor improves the insulin sensitivity in HF mice and delays the onset of diabetes in young db/db mice.