Use of preoperative computed tomography for surgical treatment of recurrent draining tracts.

OBJECTIVES: To evaluate a rational decision-making approach based on preoperative computed tomography for surgical planning in dogs and cats with recurrent draining tracts. METHODS: Retrospective evaluation of case records of animals that underwent preoperative computed tomography for surgical treatment of thoracic/abdominal recurrent draining tracts. Cases were classified according to whether a source of inflammation and/or infection, in particular foreign bodies, was identified (group 1), suspected (group 2) or neither identified nor suspected (group 3) at computed tomography. Surgery consisted of removal of the source of inflammation and/or infection (group 1), debridement or abscess drainage (group 2) or en bloc resection of diseased tissues (group 3). Clinical outcome was evaluated at least 12 months after surgery. RESULTS: A source of inflammation and/or infection was found in 100% (8 of 8), 41% (7 of 17) and 25% (3 of 12) of cases in groups 1, 2 and 3, respectively. Recurrent draining tracts resolved in 100% (8 of 8), 94% (16 of 17) and 92% (11 of 12) of cases in groups 1, 2 and 3, respectively. CLINICAL SIGNIFICANCE: The proposed strategy provided a 95% (35 of 37) cure rate, after a single procedure in 81% (30 of 37) of cases. Recovery of a foreign body at surgery was not a prerequisite for the resolution of the recurrent draining tracts.

Influence of Nitrate and Perchlorate Anions on the Kinetics of the Goethite Formation.

The synthesis of goethite by oxidation of ferrous iron solutions in the presence of metallic iron has been carried out at temperatures ranging from 20 to 70 degreesC and initial pH form 1 to 4; air flow rate is kept constant at 1 L/min. The influence of nitrate and perchlorate anions has been studied for salt concentrations ranging from 0 to 1 mol/L. The rates of iron oxidation and goethite precipitation are significantly enhanced. As expected, the nitrate anion presents many more marked oxidative properties than perchlorate. Domains of precipitation of goethite have been determined and presented in diagrams based on the factors cited above. In the presence of nitrate, magnetite precipitates in large domains corresponding to an increase in either temperature or pH. Ferrous iron concentrations are very low during magnetite precipitation, below 2 x 10(-3) g/L. They remain constant during the precipitation of goethite, in the range 12-18 x 10(-3) g/L. Copyright 1998 Academic Press.