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This paper describes highly sensitive HPLC methods for the determination of amphetamine (AP) and methamphetamine (MP) in abusers' plasma and hair samples. AP and MP were derivatized with the fluorescent reagent, DIB-Cl, to yield a highly fluorescent DIB-derivatives of AP and MP, which were then analyzed by HPLC with fluorescence detection at excitation and emission wavelengths of 325 and 430 nm, respectively. The separation was achieved on an ODS column with isocratic mobile phases composed of acetoniltrile and citrate buffer (55:45, v/v) for plasma samples and of acetonitrile-methanol-citrate buffer (45:20:37.5, v/v/v) for hair samples. The limits of detection were less than 0.87 ng/mL and 0.12 ng/mg in plasma and hair samples, respectively, for both AP and MP. The methods were then applied to the determination of MP and its metabolite AP in plasma obtained from two cases of illegally ingested MP and in one of the cases' hair received later. Case I was treated with dialysis; samples before and after dialysis were analyzed by the described method. After dialysis for 5 h, the total plasma levels of AP and MP decreased from 720 to 190 ng/mL. For case II, MP and AP levels were monitored for 3 days after digestion. Total plasma levels decreased from 57 ng/mL in the day of digestion to 11 ng/mL after 3 days. In hair samples, AP and MP could also be detected in very low concentrations.

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In this study, the feasibility of identification and abundance estimation of isada krill, Euphausia pacifica, was examined using a two‐frequency (38 and 120 kHz) method. The acoustic survey and midwater trawling were conducted off the Sanriku coast, northern part of Honshu, Japan. In one pattern, the SV difference between the two frequencies was large, and in the other, the SV difference was small. These results were interpreted by scattering models, and showed that discrimination between isada krill and walleye pollock was possible.

The abundance, spawning, growth pattern and life span of Euphausia pacifica were examined using widely collected samples off the Japanese coast of the North Pacific. Adults were widely distributed in the Oyashio area [OW; temperature at 100-m depth (T 100 ) £ 5°C] and the transitional area (5°C < T 100 £ 15°C) throughout the year, but the occurrence of large adults (>15 mm) was limited to OW and the cold waters of the transitional area (CW; 5°C < T 100 £ 10°C). Spawning occurred in OW and the transitional area throughout the year, especially in CW in spring but rarely in winter. Two modal cohorts of adults were consistently recognized in OW and CW. Cohorts of small males and females (10-11 mm length), which newly appeared in spring, grew remarkably to about 17 mm from the following spring to early summer, followed by a long period of little growth during spring-winter. Then, both male and female cohorts grew slowly and steadily after summer to a maximum of 18-19 mm by the following spring. The cohort of males disappeared after spring, but the females (about 20 mm length) were still being observed up until late summer. If the cohort of small adults is assumed to develop mainly from the spring hatching, the life span of male and female E. pacifica can be estimated to be 24 and 28 months, respectively, off northeastern Japan.