[Problems in hospital preparation of acute poisoning antagonist (methylene blue injection)].

Since some antagonists or antidotes in cases of acute poisoning are not commercially available in Japan, in many hospitals they are prepared on their premises for clinical use. However, no specific legislation for the procedures of quality assurance and informed consent of these hospital-prepared products as yet exists. Further, the standard procedures for clinical use of the hospital-prepared products have yet to be established. For the treatment of patients with methemoglobinemia, we prepared methylene blue for injectable use in our hospital. In this paper, we describe our procedures ranging from its preparation to clinical use of this product. Methylene blue injection was prepared by using reagent-grade chemicals. The quality of hospital-prepared methylene blue injection was examined in accordance with the United States Pharmacopoeia. The contents of methylene blue injection remained constant at room temperature during storage for 12-month. The sterility testing also gave negative results during the same period. In order to obtain approval for its clinical use by the in-hospital ethical committee, relevant documents such as instructions for the preparation method, product information on safety usage and consent form were created. After these procedures, clinical applications of methylene blue injection were finally initiated.

Structures of two new "minimalist" modified nucleosides from archaeal tRNA.

The wyeosine (or wye) family of tricyclic ribonucleosides from archaeal and eukaryal tRNA(Phe) constitutes one of the most complex and interesting series of posttranscriptional RNA modifications, and has been the object of numerous studies of their chemical and biological synthesis and distribution. We report the structures of two minimally elaborated wye derivatives from archaea, raising the known number of wye nucleosides to eight: 3,4-dihydro-6-methyl-3-beta-d-ribofuranosyl-9H-imidazo[1,2-a]purine-9-one (symbol imG-14), and 3,4-dihydro-6,7-dimethyl-3-beta-d-ribofuranosyl-9H-imidazo[1,2-a]purine-9-one (symbol imG2). Structures were determined primarily by mass spectrometry, and confirmed by comparison of physicochemical properties with those of chemically synthesized nucleosides. The nucleosides contain no amino acid side chains at C-7 (1H-imidazo[1,2-a]purine nomenclature) and are the only wye derivatives not methylated at N-4. These features suggest a minimal role for wye methyl groups and side chains in maintenance of anticodon stem-loop structures, and support the concept that archaeal tRNA nucleoside modification motifs are generally simpler than those of their counterparts in eukarya and bacteria.