Preoperative anxiety and postoperative pain in patients undergoing septoplasty.

OBJECTIVE: The aim of the study was to determine whether psychological variables such as preoperative anxiety could serve as predictors of the postoperative pain response. METHODS: Sixty consecutive patients with deviated nasal septum were evaluated in the pre- and postoperative periods. A questionnaire that included sociodemographic features was administered to patients. Preoperative anxiety was assessed by the Spielberger State-Trait Anxiety Index. The severity of pain was recorded with a ten-point Visual Analog Scale at the immediate postoperative period (baseline) and at postoperative hours 2, 4, 6, 12, and 24. RESULTS: Sixty patients met the eligibility criteria for the study. Of the 60 patients (39 men and 21 women) whose charts were reviewed, the mean age was 30.9 ± 12.6 years for men and 32.8 ± 10.4 years for women. The mean State-Trait Anxiety Index score was 44.3 ± 7.5 (range 29-67). No significant relationship was found between the patients' self-reports of postoperative pain and sociodemographic variables such as age and educational status. Men and women showed significant differences with respect to pain in the immediate and late postoperative periods. Correlation tests identified a significant relationship between patients' preoperative anxiety and postoperative pain in both the immediate and late periods. CONCLUSIONS: The results of this study suggest that early interventions to minimize the preoperative anxiety stress response may affect the postoperative pain response.

Determination of Vitamin B12 in food products and in premixes by reversed-phase high performance liquid chromatography and immunoaffinity extraction.

A new, faster and simple method to quantify Vitamin B12, both in foods and in premixes, by reversed-phase liquid chromatography with UV detection has been developed. Vitamin B12 was extracted from food products with 50 mM sodium acetate buffer pH 4.0 (at 100 degrees C for 35 min) in the presence of sodium cyanide, followed by a purification step on an immunoaffinity column prior to the LC analysis. An enzymatic hydrolysis (pepsin at 37 degrees C and pH 4 for 3 h) prior to the purification step efficiently released the bound Vitamin B12, and thus, allowed obtaining total Vitamin B12 content in food products. Vitamin B12 was monitored by UV at 361 nm after its separation on a reversed-phase narrow-bore column with a gradient of mobile phase made of water/acetonitrile and trifluoroacetic acid (TFA) 0.025%. The specificity of the method was demonstrated by the retention characteristics, UV spectra and by comparing the peak purity with the Vitamin B12 standard. The calibration graphs plotted with six concentrations of Vitamin B12 was linear with a regression coefficient R2 > 0.9997. The repeatability of the method was evaluated at different levels of concentration on six fortified products and the relative standard deviation (RSDr) was below 3.2%. The value of the relative standard deviation of the intermediate precision was below 5.6% (n = 4). The method was successfully applied to several food products and consistent results were obtained in comparison with microbiological assay (MBA). Our data demonstrate that the immunoaffinity columns are highly efficient for the purification of Vitamin B12 and that our HPLC could be used as an alternative method to the microbiological assay for the determination of Vitamin B12 in food products.