A portal vein cannulation technique for drug discovery in mice.

One approach to understanding how orally administered drugs are absorbed and metabolized involves measuring compound concentrations in portal vein blood and in systemic circulation at various time points. In mice, blood samples are generally collected through terminal bleeding, a process that requires a large number of mice and is susceptible to variation between individuals. The authors developed a portal vein cannulation procedure for serial bleeding in the mouse, using a modified catheter containing a stainless steel stylet that is implanted directly in the portal vein. To demonstrate the technique, they orally administered two different compounds to mice and obtained blood samples from the tail vein and portal vein at different time points. They analyzed compound concentrations using liquid chromatography-tandem mass spectrometry. The technique refines existing methods for pharmacokinetic studies in the mouse and reduces the number of mice required.

Infection of Aotus and Saimiri monkeys with Plasmodium gonderi.

Attempts were made to infect 4 species of New World monkeys (Saimiri boliviensis, Aotus nancymai, A. vociferans, A. azarae boliviensis) with Plasmodium gonderi, a malaria parasite of African monkeys. Sporozoites were obtained from Anopheles dirus or A. stephensi mosquitoes that fed on an infected rhesus monkey (Macaca mulatta). Inoculation of sporozoites was by injection of dissected sporozoites by either the intravenous or intrahepatic routes, or by mosquito bite. Liver biopsies done 7 or 8 days after sporozoite inoculation showed that hepatocytes of all 4 species of these New World monkeys supported exoerythrocytic stages of P. gonderi, but daily blood film examination during a 60-day observation period failed to detect blood stages of the parasite.