Model ecosystem evaluation of the environmental impacts of the veterinary drugs phenothiazine, sulfamethazine, clopidol, and diethylstilbestrol. (1/5)

Four veterinary drugs of dissimilar chemical structures were evaluated for environmental stability and penchant for bioaccumulation. The techniques used were (1) a model aquatic ecosystem (3 days) and (2) a model feedlot ecosystem (33 days) in which the drugs were introduced via the excreta of chicks or mice. The model feedlot ecosystem was supported by metabolism cage studies to determine the amount and the form of the drug excreted by the chicks or mice. Considerable quantities of all the drugs were excreted intact or as environmentally short-lived conjugates. Diethylstilbestrol (DES) and Clopidol were the most persistent molecules, but only DES bioaccumulated to any appreciable degree. Phenothiazine was very biodegradable; sulfamethazine was relatively biodegradable and only accumulated in the organisms to very low levels. Data from the aquatic model ecosystem demonstrated a good correlation between the partition coefficients of the drugs and their accumulation in the fish.  (+info)

Efficacy of selected oral chemotherapeutants against Ichthyophthirius multifiliis (Ciliophora: Ophyroglenidae) infecting rainbow trout Oncorhynchus mykiss. (2/5)

The chemotherapeutic efficacy of 6 in-feed compounds against Ichthyophthirius multifiliis Fouquet, 1876 was assessed using experimental infections of rainbow trout Oncorhynchus mykiss (Walbaum) fingerlings. Trial doses of 104 ppm amprolium hydrochloride or 65 ppm clopidol fed to fish for 10 d prior to infection significantly reduced the number of trophonts establishing in trout fingerlings by 62.0 and 35.2% respectively. In-feed treatments of infected trout with either 63 or 75 ppm amprolium hydrochloride, 92 ppm clopidol, or 38, 43 or 47 ppm salinomycin sodium for 10 d also significantly reduced the number of surviving trophonts by 77.6 and 32.2% for amprolium, 20.1% for clopidol and 80.2, 71.9 and 93.3% respectively for salinomycin sodium.  (+info)

Antimalarial quinolones: synthesis, potency, and mechanistic studies. (3/5)

In the present article we examine the antiplasmodial activities of novel quinolone derivatives bearing extended alkyl or alkoxy side chains terminated by a trifluoromethyl group. In the series under investigation, the IC50 values ranged from 1.2 to approximately 30 nM against chloroquine-sensitive and multidrug-resistant Plasmodium falciparum strains. Modest to significant cross-resistance was noted in evaluation of these haloalkyl- and haloalkoxyquinolones for activity against the atovaquone-resistant clinical isolate Tm90-C2B, indicating that a primary target for some of these compounds is the parasite cytochrome bc1 complex. Additional evidence to support this biochemical mechanism includes the use of oxygen biosensor plate technology to show that the quinolone derivatives block oxygen consumption by parasitized red blood cells in a fashion similar to atovaquone in side-by-side experiments. Atovaquone is extremely potent and is the only drug in clinical use that targets the Plasmodium bc1 complex, but rapid emergence of resistance to it in both mono- and combination therapy is evident and therefore additional drugs are needed to target the cytochrome bc1 complex which are active against atovaquone-resistant parasites. Our study of a number of halogenated alkyl and alkoxy 4(1H)-quinolones highlights the potential for development of "endochin-like quinolones" (ELQ), bearing an extended trifluoroalkyl moiety at the 3-position, that exhibit selective antiplasmodial effects in the low nanomolar range and inhibitory activity against chloroquine and atovaquone-resistant parasites. Further studies of halogenated alkyl- and alkoxy-quinolones may lead to the development of safe and effective therapeutics for use in treatment or prevention of malaria and other parasitic diseases.  (+info)

Determination of residual clopidol in chicken muscle by capillary gas chromatography-negative chemical ionization-mass spectrometry. (4/5)

A selective, sensitive gas chromatography-mass spectrometry (GC-MS) method with negative chemical ionization (NCI) was developed for the detection and quantification of clopidol in chicken muscle. Chicken muscle samples were extracted with acetonitrile and concentrated to dryness; the residue was redissolved in ethyl acetate and applied to an Alumina B cartridge for cleanup. The residue was derivatized with Sylon BFT and analyzed by GC-NCI-MS. The selected-ion monitoring mode was performed at m/z values of 156, 158, 191, and 193. The differences in the ratios for the standards and spikes in chicken muscle were within the acceptability criteria. All recoveries of the drug from chicken muscle spiked at 0.5, 5.0 and 50.0 microg/kg were 74.5-95.6% intra-day, and 71.6-94.8% inter-day, respectively, with relative standard deviations being lower than 15%. The limits of detection and quantitation were 0.1 and 0.5 microg/kg, respectively. The NCI mode had better selectivity and sensitivity than the electron impact (EI) mode for clopidol.  (+info)

Incidence, predictors and outcome of drug-eluting stent thrombosis in real-world practice. (5/5)

BACKGROUND: Traditionally, stent thrombosis (STH) has been regarded as a complication of percutaneous coronary interventions during the first 30 post-procedural days. However, delayed endothelialization associated with the implantation of drug-eluting stents (DES) may extend the risk of thrombosis beyond 30 days. Data are limited regarding the risks and the impact of this phenomenon outside clinical trials. OBJECTIVES: To evaluate the incidence, predictors and clinical outcomes of STH and premature discontinuation of thienopyridines after implantation of DES in real-world practice. METHODS: We prospectively collected data from consecutive unselected patients who underwent at least 1 DES implantation at our center from February 2006 until January 2007. The patients were followed by a phone interview or by collecting data from admission files over the course of 2 years after the implantation. Confirmed and suspected STH was defined as accepted in the medical literature. RESULTS: Three hundred fourteen patients were successfully treated with DES (436 lesions). At 20 +/- 6.7 months' follow up (median 22 months), 14 patients (4.4%) had STH (incidence density 2.7 cases/100 patients-years). Five patients had early thrombosis (0-30 days), 5 patients had late STH (31-360 days from the procedure) and 4 patients had very late STH (> 360 days). Five of the 14 patients with STH died (case fatality rate, 36%). In multivariant logistic regression analysis, history of a non-cardiac thrombotic event was a risk factor for STH (p = 0.006, odds ratio [OR] 7.7, confidence interval [CI] 1.8-32.9). Clopidogrel therapy lasting less than 3 months was an independent predictor of late and very late STH (p = 0.001, OR 10.8, CI 2.7-42.9). Independent predictors of early discontinuation of thienopyridines (+info)