Onset of resistance to fenvalerate, a pyrethroid insecticide in Argentine horn flies (Diptera: Muscidae).

Haematobia irritans (L.) horn flies recently have immigrated into Argentina from Brazil or Paraguay. Bioassays were conducted with fenvalerate to develop baseline information on pyrethroid susceptibility. Four populations tested in 1994 and 1995 were more susceptible than a laboratory strain of horn fly not exposed to insecticides since 1970, but 3 populations from Corrientes Province tested in 1996 were moderately resistant to fenvalerate, with resistance ratios ranging from 3 to 26. Argentine horn fly populations were exposed to pyrethroid treatments of pour-on, spray, and dip formulations for 4 yr before developing resistance. Horn flies in the United States developed pyrethroid resistance after 2 yr of treatment with pyrethroid ear tags.

Proximal gastric vagotomy in the emergency treatment of bleeding duodenal ulcer.

Proximal gastric vagotomy for bleeding duodenal ulcer was performed in 52 low-risk patients between 1973 and 1986. Duodenotomy without violation of the pylorus was done in all patients to allow inspection and control of the bleeding site. The median duration of operation was 3 hours and 20 minutes, although 25% of the procedures required 4 or more hours. There was no postoperative mortality and no early reoperations. Among the six patients with postoperative complications, one rebled from the ulcer and two developed prolonged gastric atony. At the time of follow-up (median, 2.9 years), 48 of the patients were alive and 4 had died of non-ulcer causes. No patient had significant postvagotomy sequelae. Ulcer recurrence was documented in six patients, and three required reoperation. Proximal gastric vagotomy is a safe, effective therapy for bleeding duodenal ulcer. Because of the length of the operation, it should be restricted to low-risk patients who are hemodynamically stable at the time of operation.