Comparative pharmacokinetics and bile transformation of R-enantiomer and racemic bambuterol after single-dose intravenous, oral administration in rats and beagle dogs.

This study was to compare pharmacokinetics and bile transformation of R-enantiomer bambuterol with its racemate. Pharmacokinetics of R-enantiomer was investigated after single-dose intravenous and three doses of oral administration to rats and beagle dogs. To compare the pharmacokinetics with racemic bambuterol, the same oral doses of racemic bambuterol were also administrated; the blood and bile samples were collected by cannulation. A validated LC-MS/MS method was used to assess the level of bambuterol in plasma and bile. After single intravenous administration, no significant differences were observed between the two drugs in pharmacokinetic data. After oral dosing of R-bambuterol, the AUCs of R-enantiomer presented linear correlation. After same oral dosing of R-enantiomer and its racemate, all the pharmacokinetic parameters were equivalent. However, the clearance and apparent distribution had different results due to species and administration route difference. The bile transformation of these two compounds was similar and implicated that liver transformation accounted for the major metabolism of them. The bioavailability of R-enantiomer and racemate were comparative and relatively high in beagle dogs. Thus, R-enantiomer had a comparative pharmacokinetic profile and bile transformation with racemic bambuterol in rats and beagle dogs. These findings provided references for further clinical study.

Long-term outcome of laparoscopic total mesorectal excision for middle and low rectal cancer.

This study aimed to assess the feasibility and long-term outcome of laparoscopic total mesorectal excision for middle and lower rectal cancer. Retrospective assessment was performed on 612 patients with middle and low rectal cancer in the surgery department of our hospital. Three-hundred and three patients underwent laparoscopic total mesorectal excision (LTME), and 309 patients underwent open TME (OTME). All the data regarding patient details, operative variables and the short- and long-term outcomes were collected and compared. The sphincter-preserving rates of the two groups were similar. The conversion rate in LTME was 2.31% (seven cases). Fourteen cases (6.67%) of protective diverting stoma were fashioned in the LTME group compared with 57 cases (26.64%) in the OTME group. The postoperative morbidity was the same in these two groups, while the postoperative period until bowel movement and hospital discharge was shorter in the LTME group (P < 0.01). The median follow-up period was 34 (6-81) months for the LTME group and 36 (6-81) months for the OTME group. Local recurrence rates, the five-year disease-free survival rate and the five-year overall survival rate showed no difference between the two groups. Laparoscopic surgery is feasible and safe in patients with middle and lower rectal cancer and can provide favorable short-term and long-term outcomes.