Developmental and behavioral effects of toe clipping on neonatal and preweanling mice with and without vapocoolant anesthesia.

Toe clipping is used to identify and genotype preweanling mice, but the procedure generates concerns relevant to pain and distress. The few pertinent studies available evaluated mice between postnatal days (PND) 3 and 7, advocate the use of toe clipping in mice PND 7 or younger, and identify handling as the most distressing aspect of the procedure. Because both toe and tail clipping may be necessary in older mice to obtain sufficient DNA for genotyping, we surmised that performing these procedures concurrently to minimize handling would be beneficial.

Efficacy and safety of stored and newly prepared tribromoethanol in ICR mice.

This study, performed in conjunction with an in vitro evaluation of tribromoethanol (TBE), consisted of three trials with three objectives. The first objective was to compare anesthetic efficacy and short-term pathologic findings of TBE, ketamine-xylazine (K-X), and sodium pentobarbital (NaP). The second objective was to evaluate how changes of TBE that occur during the perceived most favorable and least favorable storage conditions (8 weeks at 5 degrees C in the dark [5D] and 25 degrees C with exposure to light [25L], respectively) affect anesthetic efficacy and short-term pathology when compared to newly prepared TBE.

An evaluation of preparation methods and storage conditions of tribromoethanol.

This reports the in vitro portion of a study designed to establish guidelines for the preparation, storage, and use of tribromoethanol (TBE). We evaluated: 1) the purity of TBE powder from three suppliers; 2) nine methods of preparation of a 25-mg/ml (working) solution for formation of particulates and breakdown products; 3) formation of particulates and breakdown products and pH change in 1-g/ml (stock) solutions and working solutions stored under four conditions (25 degrees C and 5 degrees C in light and in dark); and 4) stock and working solutions of TBE that caused lethal effects in mice. These objectives were met by using nuclear magnetic resonance spectroscopy, gas chromatography-mass spectroscopy, particle-size and turbidity analyses, and pH strips.