Choosing sides

Intraperitoneal injection, a common method for parenteral drug administration in rodents, sometimes causes lesions in vital organs, such as the cecum. Reports do not provide a consensus as to the location of the cecum on either side of the lower abdominal cavity. Moreover, some texts give conflicting recommendations as to the preferred side for intraperitoneal injection. Here, Coria-Avila et al. investigate the location of the cecum in adult male and female albino and pigmented rat strains. They report that 71.8% of the rats examined had ceca on the left side of the abdomen, and that injections on the left side were more likely to result in a punctured cecum. See page 25

An alternative decontamination strategy

When endemic viral and parasitic infections surfaced among mice in a facility at Johannes Gutenberg University, the facility managers were hesitant to completely depopulate and restock it with SPF animals because such measures would have required shutting down the entire housing area. Instead, Wiese et al. found an alternative solution: subdividing the facility into two distinct units, then independently depopulating and restocking each unit. To compensate for a suboptimal barrier between the two units, the authors replaced the open-top caging and open-servicing system with filter-top cages and cage changing stations. Despite the high infection pressure and the barrier deficits, the authors had only a single case of recontamination. See page 31

Good for girl rats, too

Tribromoethanol (TBE), though a convenient anesthetic for rodents, has been known to cause adverse effects. Having previously reported that combining TBE with medetomidine can reduce its effective dose in male Sprague-Dawley rats, Gopalan et al. tested the effects of this anesthetic combination on female Sprague-Dawley rats. Their results suggest that the combination is effective in females as well—even when hormone levels are low—and does not influence the rats' estrous cycles. See page 36