Metabolites of ephedrines in human urine after administration of a single therapeutic dose

Ephedrine (EPH), pseudoephedrine (PEPH), phenylpropanolamine (PPA), methylephedrine (MEPH) and cathine are sympathomimetic amines. These drugs are commonly found in over-the-counter (OTC) cold medicines and some dietary supplements. In Taiwan, the misuse of these drugs has resulted in an increase in athletic violations. Excretion studies of the ephedrine-related drugs have been performed to better understand the metabolic yields of ephedrines in urine. After consuming a single clinical dose of each of these drugs, urine samples from volunteers (n=3 for each drug) were subjected to tert-butyl-methyl-ether (TBME) extraction and trifluoroacetic acid (TFAA) derivatization before gas chromatography-mass spectrometry (GC-MS) analysis. Most ephedrines were excreted unchanged in urine, including EPH (40.9%), PEPH (72.2%), and PPA (59.3%). However, only a relatively small amount of MEPH (15.5%) was excreted unchanged in urine. In addition, a trace amount of PPA (1.6%) and cathine (0.7%) was found to be the metabolites of EPH and PEPH, respectively. Urinary EPH, PEPH, and PPA reached peaks at 2-6h and disappeared in urine at approximately 24-48 h post-administration. For MEPH, the peaks of excretion extended from 4 to 12h post-administration and were undetectable at approximately 48 h. A single clinical dose of EPH (25 mg) may exceed threshold level (10 microg/mL) in sport drug testing if the urine samples are tested within approximately 8h post-administration. However, a single dose of MEPH (20 mg) never reached the threshold value (10 microg/mL).     

Release of tissue paraquat into formalin solution during fixation

Formalin-fixed tissues and formalin solutions are among the most frequently found materials in pathology and forensic science laboratories. However, these materials are seldom used for the identification of poisons for forensic toxicology purposes. In this study, the possibility that paraquat may be released from formalin-fixed tissues during the fixation process was investigated. However, because of the interference of formaldehyde on the reduction of paraquat with dithionite reagent, paraquat in formalin solutions was treated with ion-pair column chromatography and then determined by measuring the derivative spectrum of reduced paraquat. The results show that the interference of formalin on paraquat determination has been eliminated by the proposed method. Furthermore, a study on the formalin solutions of fixed organs in cases with suspected paraquat intoxication revealed that portions of tissue paraquat had been released into formalin during the fixation process. Moreover, the paraquat levels in formalin increased with increased storage time. Therefore, these data suggest that the combined concentrations of paraquat in the formalin-fixed tissues and formalin solutions might reflect more reliably the total paraquat in the postmortem tissues. This investigation could be of value to the forensic toxicologist, especially in cases in which no fresh tissue samples are available for analysis.     

全球化背景下我国青少年德育之对策研究

全球化对我国青少年德育提出了更高的要求,同时也赋予了我国青少年德育崭新的理念和丰富的德育资源。美国、新加坡、日本等几个有代表性的国家青少年德育理念、模式对我国青少年德育具有很大的启发,对研究全球化时代我国青少年德育工作的定位和对策具有一定的借鉴意义。     

Perceived Discrimination and Mexican-Origin Young Adults’ Sleep Duration and Variability: The Moderating Role of Cultural Orientations

Perceived ethnic discrimination is central to the experiences of Latino young adults, yet we know little about the ways in which and the conditions under which ethnic discrimination relates to Latino young adults’ sleep patterns. Using a sample of 246 Mexican-origin young adults (M _age  = 21.11, SD = 1.54; 50 % female), the current study investigated the longitudinal links between perceived ethnic discrimination and both sleep duration and night-to-night variability in duration, while also examining the moderating roles of Anglo and Mexican orientations in the associations. The results revealed that perceived discrimination predicted greater sleep variability, and this link was not moderated by cultural orientations. The relation between perceived discrimination and hours of sleep, however, was moderated by Anglo and Mexican orientations. Individuals with high Anglo and Mexican orientations (bicultural) and those with only high Mexican orientations (enculturated), showed no association between discrimination and hours of sleep. Individuals with low Anglo and Mexican orientations (marginalized) displayed a positive association, whereas those with high Anglo and low Mexican orientations (acculturated) displayed a negative association. The results suggest that discrimination has long term effects on sleep variability of Mexican-origin young adults, regardless of cultural orientations; however, for sleep duration, bicultural and enculturated orientations are protective.