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Abstract: This study aimed at quantifying the residual amount of azoxystrobin in Swiss chard samples grown under greenhouse conditions at two different locations (Gwangju and Naju, Republic of Korea). Samples were extracted with acetonitrile, separated by salting out, and subjected to purification by using solid‐phase extraction. The analyte was identified using liquid chromatography–ultraviolet detection. The linearity of the calibration range was excellent with coefficient of determination 1.00. Recovery at three different spiking levels (0.1, 0.5, and 4 mg/kg) ranged between 82.89 and 109.46% with relative standard deviation <3. The limit of quantification, 0.01 mg/kg, was considerably much lower than the maximum residue limit (50 mg/kg) set by the Korean Ministry of Food and Drug Safety. The developed methodology was successfully used for field‐treated leaves, which were collected randomly at 0–14 days following azoxystrobin application. The rate of disappearance in/on Swiss chard was ascribed to first‐order kinetics with a half‐life of 8 and 5 days, in leaves grown in Gwangju and Naju greenhouses, respectively. Risk assessments revealed that the acceptable daily intake percentage is substantially below the risk level of consumption at day 0 (in both areas), thus encouraging its safe consumption. [ABSTRACT FROM AUTHOR]

Osteopontin (OPN) is involved in the regulation of calcium precipitation in the brain pathology including ischemia. A 3-Nitropropionic acid (3NP) irreversibly inhibits mitochondrial complex II in the electron transport chain, with subsequent loss of transmembrane potential and calcium entry into the mitochondria. The present study examined the 3NP-induced calcium elevation in mitochondria and OPN expression in the 3NP-lesioned striatum. Rats were subcutaneously injected 3NP (15 mg÷kg) every other day for six weeks. Histological analysis, including the Hematoxylin-Eosin, Nissl, and Alizarin Red S stainings, was performed to examine the neurotoxic effects of 3NP. The expression of OPN in the striatum of 3NP-treated rats was investigated with immunohistochemistry and immunoelectron microscopy. In the striatal lesions, extensive loss of neurons and white matter bundles was detected. OPN was mainly detected in the penumbra region of the 3NP lesion. Scattered OPN expression was colocalized in the striatal neurons. After Alizarin Red S staining, the increase of calcium deposition was detected in the striatal lesions. In the electron microscopic analysis, the localization of OPN was clearly observed in the ultrastructure of mitochondria by immunoperoxidase and immunogold-silver staining techniques. Taken together, present findings suggest that calcium-induced mitochondrial swelling is highly associated with OPN expression. Thus, striatal calcium accumulation may be derived from 3NP-induced alteration in mitochondrial calcium homeostasis and pathologically associated with the induction of OPN protein.

The current study was undertaken to validate the performance for the determination of both TBA and beta-trenbolone (beta-TB) residues in porcine muscle at concentrations required to monitor compliance with the maximum residue limit (MRL). The method involves a one phase liquid-liquid extraction, cleanup with low-temperature fat precipitation, separation of the respective compounds by HPLC on a Capcell pak C(18) column, use of a methanol-water isocratic system as an eluent, and measurement by UV absorbance detection at 340 nm. Both compounds were confirmed using LC-MS/MS with electrospray interface (ESI) and a triple quadrupole (QqQ) analyzer. The method was found to be precise and accurate, with a linearity range of 1-10 microg/kg (r(2) >0.973). The intra- and interday precision showed good reproducibility with RSDs < or =13.25%. The LODs were 0.12 and 0.22 microg/kg, and the LOQs were 0.37 and 0.66 microg/kg, for TBA and beta-TB, respectively. The applicability of the method was demonstrated by analyzing real samples collected from major cities in the Republic of Korea. No residues of the selected compounds were detected in any of the samples. The advantages of our method are that it is: selective, sensitive, requires a short time for analysis (13 min), and performs simple sample extraction and clean-up procedure with low-temperature fat precipitation as compared to the previously published methods.

Using the microbial inhibition test, the single-dose pharmacokinetics of pefloxacin mesylate dehydrate were studied in six clinically normal lactating she-camels (Camelus dromedarius) after intravenous (IV) and intramuscular (IM) administration of 10 mg/kg body weight (bwt). Blood and milk samples were collected intermittently for a 48 h period, and the pharmacokinetic variables were calculated using compartmental and non-compartmental analytical methods.The plasma course of pefloxacin was best resolved to a two-compartment open model after IV administration and a two-compartment open model with first-order absorption after IM administration. Pefloxacin exhibits a long elimination-phase disposition half-life (t1/2beta) of 4.89 +/- 1.12 h after IV injection and 5.73 +/- 1.42 h after IM administration. The mean volume of distribution at steady state (Vdss) and total body clearance (Cl(tot)) values after IV dosing were 1.18 +/- 0.45 I/kg and 0.21 +/- 0.10 I/kg/h, respectively. The observed peak plasma level (Cmax) of 3.6 +/- 0.1 microg/ml was rapidly attained at 0.75 h (the time of maximum concentration Tmax) after IM administration. The areas under the concentration versus time curves (AUCs) were 44.18 +/- 9.68 microg x h/ml and 29.42 +/-6.49 microg x h/ml after IV and IM administration, respectively. The absolute bioavailability (F%) obtained after IM administration was 71.59 +/- 12.45%. Milk was penetrated quickly, with a mean peak level of 3.24 +/- 0.17 microg/ml occurring at 1.0 h. The elimination half-life was significantly shorter after IV versus IM administration (4.21 +/- 0.84 h versus 5.32 +/- 0.67 h, respectively). Ultimately, pefloxacin could be useful for treatment of udder infections in she-camels after specific assessment of susceptible microorganisms.