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H Post-treatment (h + post-treatment)
Selected AbstractsBioefficacy and mode of action of rocaglamide from Aglaia elaeagnoidea (syn. A. roxburghiana) against gram pod borer, Helicoverpa armigera (Hübner)JOURNAL OF APPLIED ENTOMOLOGY, Issue 3 2004O. Koul Abstract:, Rocaglamide, a highly substituted benzofuran, was isolated and identified as the main biologically active component in Aglaia elaeagnoidea (syn. A. roxburghiana) for gram pod borer Helicoverpa armigera (Hübner). Addition of rocaglamide to an artificial diet retarded the growth of neonate larvae in a dose-dependent manner with EC50 values of 0.76 p.p.m. These values compared favourably with azadirachtin (EC50 = 0.23 p.p.m.). However, azadirachtin was apparently more potent than rocaglamide in inducing growth inhibition via oral administration to these first stadium larvae. The candidate compound was found to have LD50 and LD95 values of 0.40 and 1.02 ,g per larva, respectively, in topical application against third instar larvae 96 h post-treatment. However, these values for azadirachtin were 8.16 and 25.8 ,g per larva for the same period. This shows that azadirachtin was less effective against third instar H. armigera larvae in inducing acute toxicity via topical treatment in comparison with rocaglamide. However, severe morphological larval deformities were observed in such azadirachtin-treated larvae during the process of ecdysis. The cytotoxic nature of rocaglamide was established by evaluating dietary utilization and the results did not implicate any antifeedant effect but the toxicity-mediated effect due to reduced efficiency of conversion of ingested food. It was obvious that feeding deterrence is not the primary mode of action but a centrally mediated effect, which could be due to the induced cytotoxicity at non-specific cellular levels. [source] Acute treatment of paediatric migraine: A meta-analysis of efficacyJOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 1-2 2008Shawna Silver Aim: To undertake a meta-analysis of all randomised controlled trials (RCTs) on the acute pharmacologic treatment of children and adolescents with migraine headache. Methods: In total, 139 abstracts of clinical trials specific to the acute treatment of paediatric migraine were appraised. Inclusion criteria required clinical trials to be randomised, blinded, placebo-controlled studies with comparable endpoints. Non- English language publications were excluded. 11 clinical trials qualified for inclusion in the final meta-analysis. Two endpoints were analysed: the proportion of patients with (1) headache relief, and (2) complete pain relief, 2 h post-treatment. Results: The following medications were included in the analysis: acetaminophen (n = 1), ibuprofen (n = 2), sumatriptan (n = 5), zolmitriptan (n = 1), rizatriptan (n = 2) and dihydroergotamine (n = 1). Results are expressed as a relative benefit (RB) conferred over placebo and the number needed to treat (NNT). Only ibuprofen and sumatriptan provided a statistically significant relative efficacy in comparison with placebo. Two hours post-treatment, ibuprofen was associated with an RB 1.50 (95% CI 1.15,1.95) in the generation of headache relief (NNT 2.4) and RB 1.92 (95% CI 1.28,2.86) in the production of complete pain relief (NNT 4.9). Sumatriptan rendered an RB 1.26 (95% CI 1.13,1.41) in headache relief (NNT 7.4) and an RB 1.56 (95% CI 1.26,1.93) in the production of complete pain relief (NNT 6.9). Conclusion: Despite the pharmacological options for the management of acute migraine, few RCTs in the paediatric population exist. Composite data demonstrate that only ibuprofen and sumatriptan are significantly more effective than placebo in the generation of headache relief in children and adolescents. [source] Pharmacokinetic comparison of orally-disintegrating metoclopramide with conventional metoclopramide tablet formulation in healthy volunteersALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 3 2009R. FASS Summary Background, Oral tablet formulations of metoclopramide are effective therapies for gastroparesis and gastro-oesophageal reflux disease; however, difficulty swallowing tablets or nausea/vomiting may reduce patient adherence to therapy. Because of this, a metoclopramide orally-disintegrating tablet (ODT) has been developed. Aim, To evaluate the bioequivalence of a single administration of a 10-mg metoclopramide ODT and a conventional 10-mg oral metoclopramide tablet in healthy volunteers. Methods, In a randomized, single-dose, crossover study, healthy volunteers received single administration of 10-mg metoclopramide ODT and 10-mg conventional metoclopramide tablet, with a 7-day interval between treatments. Serial blood samples were collected before dosing and during 24 h post-treatment. Results, Forty-one volunteers completed both treatment arms. Metoclopramide ODT was bioequivalent to conventional tablets; 90% CIs for geometric mean treatment ratios of Cmax [91.6% (90% CI, 87.7,95.8%)], AUClast [97.3% (90% CI, 94.5,100.2%)] and AUCinf [97.6% (90% CI, 94.5,100.8%)] were within the predefined range. Of the 44 volunteers included in the safety analysis, 9 (20%) reported AEs after ODT, compared with 13 (30%) after conventional tablets. Conclusion, In healthy volunteers, single administration of 10-mg metoclopramide ODT was well tolerated and bioequivalent to single administration of a conventional 10-mg metoclopramide tablet. [source] Pharmacokinetics of ivermectin after maternal or fetal intravenous administration in sheepJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 5 2008R. PÉREZ In pregnant sheep at 120,130 days of gestational age, a study was undertaken in order to characterize the pharmacokinetics and transplacental exchange of Ivermectin after maternal or fetal intravenous administration. Eight pregnant Suffolk Down sheep of 73.2 ± 3.7 kg body weight (bw) were surgically prepared in order to insert polyvinyl catheters in the fetal femoral artery and vein and amniotic sac. Following 48 h of recovery, the ewes were randomly assigned to two experimental groups. In group 1, (maternal injection) five ewes were treated with an intravenous bolus of 0.2 mg ivermectin/kg bw. In group 2, (fetal injection) three ewes were injected with an intravenous bolus of 1 mg of ivermectin to the fetus through a fetal femoral vein catheter. Maternal and fetal blood and amniotic fluid samples were taken before and after ivermectin administration for a period of 144 h post-treatment. Samples were analyzed by liquid chromatography (HPLC). A computerized non-compartmental pharmacokinetic analysis was performed and the results were compared by means of the Student t-test. The main pharmacokinetic changes observed in the maternal compartment were increases in the volume of distribution and in the half-life of elimination (t½,). A limited maternal-fetal transfer of ivermectin was evidenced by a low fetal Cmax (1.72 ± 0.6 ng/mL) and AUC (89.1 ± 11.4 ng·h/mL). While the fetal administration of ivermectin resulted in higher values of clearance (554.1 ± 177.9 mL/kg) and lower values of t½, (8.0 ± 1.4 h) and mean residence time (8.0 ± 2.9 h) indicating that fetal-placental unit is highly efficient in eliminating the drug as well as limiting the transfer of ivermectin from the maternal to fetal compartment. [source] The neurokinin-1 antagonist activity of maropitant, an antiemetic drug for dogs, in a gerbil modelJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 4 2007V. DE LA PUENTE-REDONDO Maropitant is a novel synthetic nonpeptide neurokinin type 1 (NK1) selective receptor antagonist, recently developed for use in the dog as an antiemetic. The in vivo functional activity of maropitant was investigated in the gerbil foot-tapping model, to determine the ability of maropitant to penetrate the central nervous system and inhibit foot-tapping induced by the selective NK1 agonist GR73632. In comparison with CP-122,721, a previously characterized NK1 receptor antagonist, maropitant (1 mg/kg by s.c. injection) was found to inhibit foot-tapping for significantly longer (P < 0.01). Inhibition of foot-tapping by maropitant was 100% at 2 h and approximately 50% at 8 h postdosing. The mean brain:plasma concentration ratio at 8 h post-treatment was 3.59. These data demonstrate the central functional action of maropitant as a selective and potent NK1 receptor antagonist and help to support and explain its clinical potential as a broad-spectrum antiemetic agent. [source] Plasma achiral and chiral pharmacokinetic behaviour of intravenous oxfendazole co-administered with piperonyl butoxide in sheepJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 1 2002S. SÁNCHEZ Co-administration of piperonyl butoxide (PB) potentiates fenbendazole (FBZ) in small ruminants. The resultant increase in bioavailability of FBZ and its metabolite oxfendazole (OFZ) has important implications for the efficacy of these drugs against benzimidazole (BZD)-resistant strains of Teladorsagia circumcincta. This study evaluated the racemic (achiral) and enantiomeric (chiral) plasma disposition kinetics of OFZ and its metabolites after the co-administration of PB and OFZ in sheep. Six 6,8-month-old, parasite-free, female Dorset sheep (30,40 kg) were used in a two-phase crossover experiment. In phase I, three sheep received 30 mg/kg PB orally, followed by a single intravenous (i.v.) injection of OFZ at 5 mg/kg. The other three animals were treated similarly except that 5 mL of water replaced PB. In phase 2, treatments for the two groups were reversed and were given 14 days after the initiation of phase I. Three analytes OFZ, FBZ and fenbendazole sulphone (FBZSO2) were recovered in plasma up to 48 h post-treatment in both experimental groups. Achiral and chiral pharmacokinetic (PK) profiles for OFZ, after the co-administration of PB, were characterized by a significantly greater area under the concentration,time curve (AUC) and a longer mean residence time (MRT). Chiral OFZ distribution ratios were comparable in both treatment groups. Piperonyl butoxide treatment markedly influenced the plasma PK profiles for FBZ and FBZSO2 following OFZ administration. Production of FBZ was enhanced as reflected by increased (> 60%) AUC, delayed Tmax and a significantly delayed (> 45%) elimination (t½el). Although AUC values for FBZSO2 were not significantly different between groups, this metabolite was depleted more slowly from plasma (t½el > 60% and MRT > 42%) following PB treatment. This study demonstrated that PB co-administration is associated with an inhibition of OFZ biotransformation, as evidenced by the significantly higher plasma concentrations of OFZ and FBZ, and this could have important implications in terms of antiparasite therapy against BZD-resistant parasite strains. [source] Permethrin resistance ratios compared by two methods of testing nymphs of the German cockroach, Blattella germanicaMEDICAL AND VETERINARY ENTOMOLOGY, Issue 2 2000H. Ladonni Summary For the German cockroach, Blattella germanica L. (Dictyoptera: Blattellidae), the permethrin resistance ratio (RR) was assessed by topical application and by tarsal contact tests, using first-instar nymphs of five strains from Tehran, Iran. Each test was replicated three or four times with 10 nymphs aged 2,3 days; mortality was scored 24 h post-treatment. The reference susceptible strain showed LD50 permethrin 0.0175 ,l/nymph from topical application, KT50 of 8.41 min and LT50 of 12.82 following tarsal contact with permethrin 15 mg/m2. In four wild strains (F1 generation) the RR varied from 4.14 to 4.7 for mortality after topical application, from 4.2 to 6.45 for mortality and 17,27 for knockdown following tarsal contact tests. Hence, overall knockdown results gave much higher RRs than for mortality data. Resistance ratios based on both methods of treatment were very similar: one strain showed a slightly higher value by topical application (RR 4.6 vs. 4.2, i.e. 1.1-fold difference) whereas the other three strains gave slightly greater RR (1.2,1.4 fold) by tarsal contact. Resistance was abolished by cotreatment with the synergist piperonyl butoxide plus permethrin (ratio 3 : 1 required for full efficacy), indicating that mixed-function oxidases were inhibited as a major metabolic pathway in all four resistant strains. [source] Impact of spray application methodology on the development of resistance to cypermethrin and spinosad by fall armyworm Spodoptera frugiperda (JE Smith)PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 11 2006Ali Al-Sarar Abstract The development of resistance to an insecticide under various types of application method has yet to be reported in the literature. Five fall armyworm Spodoptera armigera (JE Smith) colonies were reared in a chamber for ten generations before starting topical application bioassays. From each colony, 200,500 third,fourth-instar larvae were fed for 72 h on corn plants sprayed with cypermethrin or spinosad at minimum application rate (20 g ha,1) using a small droplet size nozzle XR8001VS (volume median diameter Dv0.5 = 163 µm) or a large droplet size nozzle XR8008VS (Dv0.5 = 519 µm). Surviving larvae were transferred to untreated corn leaves to complete their life cycle. Next-generation third-instar larvae of each colony were topically dosed with technical cypermethrin or spinosad at 1 µL per larva, and mortality was recorded 24 h post-treatment. The results indicated that cypermethrin demonstrated an insecticidal activity greater than that of spinosad, and the cypermethrin regression lines moved to the right faster than those for spinosad, indicating an increased tolerance of cypermethrin. Generally, larvae from all generations (F1,F7) under the XR8008VS treatments were less susceptible to cypermethrin and developed resistance faster and to higher levels than larvae from the XR8001VS treatments. The confidence limits (95%) of LD50 for all spinosad treatments indicated that there was no significant difference from the LD50 value of the susceptible reference strain. The results are a first indication that application technology/insecticide reaction may affect the rapidity of resistance development in certain pest/plant scenarios, but field studies are needed to confirm this conclusion. Copyright © 2006 Society of Chemical Industry [source] The role of glutathione S -transferases in the detoxification of some organophosphorus insecticides in larvae and pupae of the yellow mealworm, Tenebrio molitor (Coleoptera: Tenebrionidae)PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 6 2001Iason Kostaropoulos Abstract The correlation between the natural levels of glutathione S -transferase (GST) and the tolerance to the organophosphorus insecticides parathion-methyl and paraoxon-methyl, as well as the interaction of affinity-purified enzyme and the insecticides were investigated in order to collect further information on the role of the glutathione S -transferase system as a mechanism of defence against insecticides in insects. The studies were carried out on the larvae and pupae of the coleopteran Tenebrio molitor L, which exhibit varying natural levels of GST activity. Stage-dependent susceptibility of the insect against insecticides was observed during the first 24,h. However, 48,h after treatment, the KD50 value increased significantly due to the recovery of some individuals. Simultaneous injection of insecticide with compounds which inhibit GST activity in vitro caused an alteration in susceptibility of insects 24 or 48,h post-treatment, depending on stage and insecticide used. Inhibition studies combined with competitive fluorescence spectroscopy revealed that the insecticides probably bind to the active site of the enzyme, thus inhibiting its activity towards 1-chloro-2,4-dinitrobenzene in a competitive manner. High-performance liquid chromatography and gas chromatography revealed that T molitor GST catalyses the conjugation of the insecticides studied to a reduced form of glutathione (GSH). From the above experimental results, it is considered that GST offers a protection against the organophosphorus insecticides studied by active site binding and subsequent conjugation with GSH. © 2001 Society of Chemical Industry [source] Leaf expansion in Phaseolus: transient auxin-induced growth increasePHYSIOLOGIA PLANTARUM, Issue 4 2007Christopher P. Keller Control of leaf expansion by auxin is not well understood. Evidence from short-term exogenous applications and from treatment of excised tissues suggests auxin positively influences growth. Manipulations of endogenous leaf auxin content, however, suggest that long-term auxin suppresses leaf expansion. This study attempts to clarify the growth effects of auxin on unifoliate (primary) leaves of the common bean (Phaseolus vulgaris) by reexamining the response to auxin treatment of both excised leaf strips and attached leaves. Leaf strips, incubated in culture conditions that promoted steady elongation for up to 48 h, treated with 10 ,M,-naphthalene acetic acid (NAA) responded with an initial surge of elongation growth complete within 10 h, followed by insensitivity. A range of NAA concentrations from 0.1 to 300 ,M induced increased strip elongation after 24 and 48 h. Increased elongation and epinastic curvature of leaf strips was found specific to active auxins. Expanding attached unifoliates treated once with aqueous auxin NAA at 1.0 mM showed both an initial surge in growth lasting 4,6 h followed by growth inhibition sustained at least as long as 24 h post-treatment. Auxin-induced inhibition of leaf expansion was associated with smaller epidermal cell area. Together, the results suggest increasing leaf auxin first increases growth and then slows growth through inhibition of cell expansion. Excised leaf strips retain only the initial increased growth response to auxin and not the subsequent growth inhibition, either as a consequence of wounding or as a consequence of isolation from the plant. [source] | |||||||||||||