BACKGROUND: Icaridin and DEET are common insect repellents widely used on human skin and clothing (skin-insect repellents [skin-IR]) to repel common pests, such as mosquitoes and biting flies. Novel analytical methods for urinary skin-IR exposure biomarkers that can be effectively applied in epidemiological studies and provide strong evidence related to risk assessment associated with daily exposure are required. In this study, we aimed to develop a method for analyzing the concentrations of icaridin, DEET, and two DEET metabolites N,N-diethyl-3-(hydroxymethyl) benzamide and 3-(diethylcarbamoyl) benzoic acid in human urine. METHODS: In this analysis, after formic acid-induced acidification of the urine sample, exposure biomarkers were extracted using solid-phase extraction composed of a modified polystyrenedivinylbenzene polymer for reversed phase (hydrophobic) retention. Subsequently, high-performance liquid chromatography-tandem mass spectrometry was performed within 10 min for a separation analysis. The present method was applied to five Japanese adults (aged 20-43 years) who used icaridin or DEET-containing products within a week. RESULTS: Limits of detection were 0.06-0.11 µg/L. Extraction recoveries were 74%-88%. The intraday and interday variations were 1.5-17.5 and 0.9-15.8% relative standard deviation, respectively. All exposure biomarkers were successfully detected in all five adults. Urinary concentrations of exposure biomarkers reached their maximum values within 15 h after starting to use skin-IR. CONCLUSIONS This method was successful in measuring urinary exposure biomarkers of skin-IR, including icaridin and DEET. Moreover, this study presents the first application of biomonitoring of urinary icaridin concentrations after using a commercial product.
Humans ; Solid Phase Extraction/methods* ; Tandem Mass Spectrometry/methods* ; Adult ; Insect Repellents/urine* ; DEET/urine* ; Young Adult ; Male ; Japan ; Female ; Chromatography, Liquid ; Biomarkers/urine* ; Chromatography, High Pressure Liquid ; East Asian People

Background and Purpose : Many cases of amnesia caused by thalamic hemorrhage involve anterior nucleus hemorrhage, dorsomedial nucleus hemorrhage, and intraventricular rupture. In the present study, intraventricular rupture was studied with a focus on cases with hematoma compression at the fornix. Methods : Of 116 patients with thalamic hemorrhage admitted to our hospital, 50 patients aged <70 years who had hemorrhage during their first stroke confined to the thalamus, internal capsule, and corona radiata, and who neither developed hydrocephalus nor showed dementia prior to onset were investigated. Thalamic hemorrhages were classified by CT findings and the extent of intraventricular rupture. Memory was studied by the FIM memory scores on admission and discharge. Results and Conclusion : Patients with dorsomedial nucleus hemorrhage showed no tendency toward amnesia and were equivalent to patients with posterolateral nucleus hemorrhage, which does not usually result in amnesia on its own. Of the 30 patients with posterolateral nucleus hemorrhage, a high degree of amnesia was observed in the 18 with intraventricular rupture. A high proportion of patients with dorsomedial nucleus hemorrhage experienced intraventricular rupture (5 of 6 patients). Equivalent degrees of amnesia were observed in patients with intraventricular rupture with dorsomedial nucleus hemorrhage and those with posterolateral nucleus hemorrhage. The present findings in conjunction with the fact that amnesia in thalamic hemorrhage involves episodic memory impairment suggest that amnesia in patients with dorsomedial or posterolateral nucleus hemorrhage or with intraventricular rupture does not stem from damage to the dorsomedial nucleus, which is part of the Yakovlev circuit involved in emotional memory. Instead, the primary cause appears to be the effects of intraventricular rupture on the Papez circuit surrounding the lateral ventricle and foramen of Monro.