Evaluation of textile dye degradation due to the combined action of enzyme horseradish peroxidase and hydrogen peroxide.

The kinetic parameters of the oxidant action of the combination of enzyme horseradish peroxidase (HRP) with hydrogen peroxide in the degradation of methylene blue dye were investigated. Twenty-one percent of color removal was obtained at pH 5.0 and temperature of 30 °C. Under these conditions, the kinetic parameters K m and V max of enzymatic reactions were determined for hydrogen peroxide in the absence of methylene blue dye (K m = 17.3 mM; V max = 1.97 mM/min) and in the presence of methylene blue dye (K m = 0.27 mM, V max = 0.29 µM/min). By means of analysis of phosphorescence, the presence of reactive oxygen species was detected in the form of singlet oxygen through the redox reaction between HRP and hydrogen peroxide. The existence of this reactive species is directly dependent on the concentration of hydrogen peroxide in the aqueous solution.

The ONSTEP inguinal hernia repair technique: initial clinical experience of 693 patients, in two institutions.

PURPOSE: Experience with a novel hernioplasty procedure--the ONSTEP approach--for inguinal hernia repair in a large series of patients performed by two surgeons at two institutions is described, focusing in particular on the duration of surgery, the time taken to return to normal activities, chronic pain, complication and recurrence rates. METHODS: Adult patients underwent inguinal hernia repair using the ONSTEP approach. The hernia defect was repaired using a PolySoft™ hernia patch. Patients were followed up for 1 year for pain, complications and recurrences. RESULTS: A total of 693 patients underwent ONSTEP inguinal hernia repair. The mean duration of surgery (± SD) was 17 ± 6 min; the time to discharge from hospital was less than 24 h in all patients; and the mean time to return to normal daily activities was 6.1 ± 3.0 days. The overall complication rate was 1.0 % and the overall recurrence rate was 0.6 %. Residual pain was present in 4 patients at 6 months and was cured by removal of the memory ring in 3 patients and disappeared spontaneously in one case, so that there was no case of chronic pain at 1 year. CONCLUSIONS: The ONSTEP inguinal hernia repair technique described is simple, quick to perform, produces consistent results and is associated with very low overall complication, chronic pain and recurrence rates. It may offer an alternative to both Lichtenstein and laparoscopic inguinal hernia repair.