Removal of 241Am from aqueous nitrate solutions by liquid surfactant membrane containing 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester as ion carrier.

A liquid surfactant membrane (LSMs) containing 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (H(2)A(2)) was tested for the extraction of americium(III) from aqueous nitrate solutions of different compositions. Span 80 a surface-active agent and 0.5M HNO(3) were used as emulsion stabilizer and internal phase respectively in the LSM system. Influence of some important experimental parameters such as pH of the exterior phase, ionic impurities in the exterior phase, concentration of H(2)A(2) and Span80 in liquid membrane phase on the LSM permeation process was systematically studied. The maximum efficiency of Am(III) extraction among group of experiments was 93+/-2% with modified permeability coefficient=1.21+/-0.02min(-1) and the corresponding concentration factor of Am(III) in the receiving phase was 10.5+/-0.2. Extraction of commonly associated fission product elements such as (137)Cs, (152,154)Eu, (90)Sr, (95)Zr, (144)Ce, (95)Nb and (103)Ru was also investigated from feed solution in the exterior phase adjusted at different pH. In a single batch of extraction, more than 90% removal and about 10 times concentration of Am(III) was obtained from uranium and plutonium depleted (process of Plutonium Uranium Recovery by Extraction) waste solution. A complete demulsification of metal loaded emulsion was obtained by chemical using 2-ethylhexanol and physical using freeze thaw method.

Topical antibiotics in the high-risk biliary surgical patient. A prospective, randomized study.

This randomized, prospective study has evaluated the efficacy of topical antibiotics in preventing infective complications in patients undergoing high-risk biliary surgery. Sixty-nine patients who underwent bile duct exploration, choledochoenteric anastomosis, or cholecystectomy, either for acute cholecystitis or because they were older than 65 years of age, were randomized to the following three groups: Group I, topical antibiotics alone (22 patients); Group II, cefoxitin and topical antibiotics (24 patients); and Group III, penicillin, tobramycin, clindamycin, and topical antibiotics (23 patients). The incidence of infective complications was no different among the groups. There was one wound infection in each group, one episode of bacteremia in Group II, and no intraabdominal abscesses. This study has demonstrated that parenteral antibiotics administered prophylactically in the perioperative period offer no additional benefit over the use of effective topical antibiotics used intraoperatively in patients undergoing high-risk biliary surgery.

Closed-suction versus Penrose drainage after cholecystectomy. A prospective, randomized evaluation.

Closed-suction drainage was compared prospectively to open, passive drainage (Penrose drains) in 128 patients undergoing cholecystectomy. Patients were randomized at the time of operation to receive either closed-suction drains (Group I, 67 patients) or Penrose drains (Group II, 61 patients). The preoperative clinical parameters of the two groups were similar. The patients in Group I when compared with those in Group II had a shorter duration of drainage (3.3 days and 4.1 days, respectively, p less than 0.01), a lesser volume of drainage in the first 48 hours postoperatively (78 ml and 132 ml, respectively, p less than 0.001), a decreased incidence of fever on the night of operation (24 of 67 patients and 39 of 61 patients, respectively, p less than 0.05) and on the first postoperative day (26 of 67 patients and 32 of 61 patients, respectively, p less than 0.05), and a lower leukocyte count on the first postoperative day (12,000 cells/mm3 and 14,100 cells/mm3, respectively, 0.05 less than p less than 0.1). Patients in Group I tended to have a lower rate of wound infection (1 of 67 patients versus 5 of 61 patients in Group II, 0.05 less than p less than 0.1) and had a much lower incidence of drain site tenderness (8 of 67 patients in Group I versus 24 of 61 patients in Group II, p less than 0.05). This study demonstrates the superiority of closed-suction drains over open, passive drains after cholecystectomy.

Mesenteric cysts.

Mesenteric cysts continue to be of special interest because of their diverse presentation and the lack of definitive diagnostic tests. Nine patients with mesenteric cysts were treated at St. Agnes Hospital between 1973 and 1984. The most common location was in small bowel mesentery (67%) followed by the mesocolon (33%). The mesenteric cysts were incidental findings in four of the nine patients (45%). Enucleation was the treatment of choice in eight patients (88%), followed by right hemicolectomy in one patient. Two patients had complications, one wound infection and one urinary tract infection. Simple enucleation has proven to be adequate treatment in most instances. Large bowel resection may be necessary when mesenteric cysts are located in the mesocolon and enucleation is not feasible without compromising the blood supply to the adjacent bowel.