Hearing preservation surgery in acoustic neuroma. Slow progress and new strategies.

Quality and rate of preserved hearing are crucial to make hearing preservation surgery a viable treatment. A long-term experience with hearing preservation surgery, with tumour size and hearing as admission criteria, was evaluated to assess which size and hearing allowed a high rate of success. The hearing outcome in relation to size of tumour and pre-operative hearing was retrospectively reviewed in a consecutive series of 115 cases of sporadic acoustic neuroma which were operated on with hearing preservation surgery. Inclusion criteria were hearing with ≤ 30 dB pure tone average and ≥ 70% Speech Discrimination Score. The size was ≤ 15 mm in the first series of 51 cases, and ≤ 10 mm in the second series of 64 cases. Pre-operative and post-operative pure tone average were measured at 0.5 to 4.0 KHz, and speech discrimination score at ≤ 40 dB above perception. Post-operative hearing within 30 dB pure tone average and 70% speech discrimination score was considered socially useful hearing and successful outcome. The change to 40 dB pure tone average and 60% speech discrimination score from a pre-operative 30 pure tone average/70% speech discrimination score was considered an acceptable outcome. Patients with a tumour of ≤ 10 mm size in the cerebello-pontine-angle and hearing within 20 dB pure tone average/80% speech discrimination score had a success rate of 76%. Patients with hearing between the 20 dB pure tone average/80% speech discrimination score and 30 dB pure tone average/ 70% speech discrimination score had a success rate of 41%, which increased to 53% if the limit to success was set at 40 dB pure tone average/60% speech discrimination score. Patients with a tumour larger than 10 mm or hearing worse than 30 dB pure tone average/70% speech discrimination score had a poor preservation rate. In conclusion, hearing preservation surgery on a ≤ 10 mm acoustic neuroma with good hearing had a high rate of success and appeared to be a realistic treatment option which could be integrated with observation and radiotherapy in updated guidelines of treatment.

Separation and determination of denatured caseins by hydrophobic interaction chromatography Part II. Method validation and applications.

A method recently described for the separation of denatured alpha-, beta- and kappa-caseins by hydrophobic interaction chromatography was validated by the analysis of reference skim milk powder (BCR-063R) certificated for total nitrogen content. The method is based on fast and easy solubilization of commercial and real samples by 4.0 M guanidine thiocyanate and elution on a TSK-Gel Phenyl-5PW column (TosoHaas) in the presence of 8.0 M urea in the mobile phase. No preliminary precipitation or separation of the casein fraction is required. A linear relationship between the concentration of casein and peak area (UV absorbance detector at 280 nm) was obtained over the concentration range 0.5-60 microM. The detection limits for alpha-, beta- and kappa-caseins ranged between 0.30 and 0.65 microM. The precision of the method was evaluated; the relative standard deviation for alpha-, beta- and kappa-casein determination ranged between 2.2 and 2.7% for standard solutions and between 3.5 and 6.2% for real sample solutions. The mean casein content found in 10 aliquots of BCR-063R calculated with respect to the total protein content (estimated on the basis of certified total nitrogen content) was 79.1+/-2.7%. Results of linear fitting of standard additions data for alpha-, beta- and kappa-caseins to BCR-063R were compared with linear fitting of alpha-, beta- and kappa-casein calibration data. The method was applied to commercial caseins and to 31 real, raw samples [processed cow's milk (pasteurised, UHT-treated), follow-up milk powders, cream, cheeses, casein-free infant formulae, cookies for babies containing milk proteins] with the aim of showing the wide applicability of the method in order to determine alpha-, beta- and kappa-caseins.

Triterpenes from Licania licaniaeflora.

Nine triterpenoids with lupane, oleanane, and ursane skeleton have been isolated and characterized from the leaves of Licania licaniaeflora. The structural identification was based on (1)H and (13)C-NMR spectral data.