Removal of dimethyl phthalate in water by non-thermal air plasma treatment

In this study, the effect of a non-thermal microplasma array on the degradation of dimethyl phthalate (DMP) solution was investigated using a high pressure liquid chromatograph and mass spectrometer (LC-MS).

Metronidazole and Hydroxymetronidazole Central Nervous System Distribution: 2. Cerebrospinal Fluid Concentration Measurements in Patients with External Ventricular Drain

ABSTRACTThis study explored metronidazole and hydroxymetronidazole distribution in the cerebrospinal fluid (CSF) of brain-injured patients. Four brain-injured patients with external ventricular drain received 500 mg of metronidazole over 0.5 h every 8 h. CSF and blood samples were collected at steady state over 8 h, and the metronidazole and hydroxymetronidazole concentrations were assayed by high-pressure liquid chromatograph. A noncompartmental analysis was performed. Metronidazole is distributed extensively within CSF, with a mean CSF to unbound plasma AUC0–τratio of 86% ± 16%. However, the concentration profiles in CSF were mostly flat compared to the plasma profiles. Hydroxymetronidazole concentrations were much lower than those of metronidazole both in plasma and in CSF, with a corresponding CSF/unbound plasma AUC0–τratio of 79% ± 16%. We describe here for the first time in detail the pharmacokinetics of metronidazole and hydroxymetronidazole in CSF.

Biodegradation of bisphenol A in the aquatic environment

Biodegradation potential of bisphenol A (BPA) in the aquatic environments was investigated using 3 activated sludge and 44 river water microcosms. The biodegradation potential was exhibited by most of the tested microcosms; 3 activated sludge and 40 river water microcosms. However, only 6 river water microcosms could completely mineralize BPA, and the others showed accumulation of common metabolites which were detected as 2 peaks according to a high-pressure liquid chromatograph. In total 19 BPA-degrading bacteria were isolated from activated sludge and river water samples, and their BPA degradation property was also investigated. Although all the BPA-degrading bacteria could grow on BPA and remove about 70–80% of TOC derived from BPA, they accumulated 2 common metabolites, and they could not be removed by the prolonged cultivation up to more than 1 month. These 2 metabolites were identified as 2,3-bis(4-hydroxyphenyl)-1,2-propanediol and p-hydroxyphenacyl alcohol in the culture of a typical BPA-degrading bacterium. The experimental results suggested that BPA-degrading bacteria ubiquitously exist in the aquatic environments, but that they cannot completely degrade BPA, leading to the accumulation of more recalcitrant metabolites. For complete BPA degradation, the presence of microbes which can degrade the metabolites seems necessary together with BPA-degrading bacteria.

Cisternal Cerebrospinal Fluid Concentrations of Morphine following Intrathecal and Epidural Administration in the Baboon

Eleven baboons, anaesthetised with ketamine, had catheters introduced into the cisterna magna. Morphine was injected at lumbar level intrathecally in six and epidurally in five. Cisternal CSF was sampled hourly and the morphine concentration measured using a high pressure liquid chromatograph. In two cases following intrathecal injection peaks of 180 ng/ml at 4 hours, and 2,200 ng/ml at 3 hours were detected. In the latter case there was associated error in sampling therefore this baboon had a repeat injection four weeks later. The maximum level of morphine obtained then was 139 ng/ml at 4 hours. In the epidural group peaks of 113 ng/ml and 53 ng/ml at 1 hour were measured in 2 baboons and 27 ng/ml at 6 hours in a third. In all six other baboons following either procedure no morphine was detected in the cisterna. We conclude that morphine injected either intrathecally or epidurally in primates does migrate centrally in varying quantities. This finding would seem to have some bearing on the unpredictability of reported episodes of respiratory depression following intraspinal morphine.