Pharyngocutaneous fistula is the most common complication of total laryngectomy. The management of this problem increases hospitalization time and delays initiation of postoperative radiotherapy, where indicated. To identify factors predisposing to the development of pharyngocutaneous fistula, we reviewed the postoperative courses of 293 patients who underwent total laryngectomy at our clinic. General factors taken into account were concurrent diseases such as diabetes, liver diseases, or chronic anemia; local factors included radiotherapy before and after surgery, preoperative tracheostomy, type of cervical lymph node removal, and method of pharyngeal closure. We then compared our data with those reported in the literature by other authors. Last, we applied the Fisher exact test to a correlation we found between the higher incidence of fistula in patients with diabetes, liver diseases, or anemia. The local factor that turned out to be statistically most significant for the development of fistula was preoperative radiotherapy.

In the analysis of our results, the surgical approach proved to be the principal prognostic factor in the anatomic outcome of myringoplasty. The results obtained suggest that the principal factors influencing the outcome of myringoplasty are technical and not clinical.

The risk posed by complex chemical mixtures in the environment to wildlife and humans is increasingly debated, but has been rarely tested under environmentally relevant scenarios. To address this issue, two mixtures of 14 or 19 substances of concern (pesticides, pharmaceuticals, heavy metals, polyaromatic hydrocarbons, a surfactant, and a plasticizer), each present at its safety limit concentration imposed by the European legislation, were prepared and tested for their toxic effects. The effects of the mixtures were assessed in 35 bioassays, based on 11 organisms representing different trophic levels. A consortium of 16 laboratories was involved in performing the bioassays. The mixtures elicited quantifiable toxic effects on some of the test systems employed, including i) changes in marine microbial composition, ii) microalgae toxicity, iii) immobilization in the crustacean Daphnia magna, iv) fish embryo toxicity, v) impaired frog embryo development, and vi) increased expression on oxidative stress-linked reporter genes. Estrogenic activity close to regulatory safety limit concentrations was uncovered by receptor-binding assays. The results highlight the need of precautionary actions on the assessment of chemical mixtures even in cases where individual toxicants are present at seemingly harmless concentrations.

Site-directed mutagenesis and functionalization of gold surfaces have been combined to obtain a stable immobilization of the heme domain of cytochrome P450 BM3 from Bacillus megaterium. Immobilization experiments were carried out using the wild type protein bearing the surface C62 and C156 and the site-directed mutants C62S, the C156S, and the double mutant C62S/C156S (no exposed cysteines). The gold surface was functionalized using two different spacers: cystamine- N-succinimidyl 3-maleimidopropionate and dithio-bismaleimidoethane, both leading to the formation of maleimide-terminated monolayers capable of covalent linkage to cysteine. Tapping mode atomic force microscopy experiments carried out on cystamine- N-succinimidyl 3-maleimidopropionate derivatized gold led to good images with expected molecular heights (5.5-6.0 nm) for the wild type and the C156S mutant. These samples also gave measurable electrochemical signals with midpoint potentials of -48 and -58 mV for the wild type and C156S, respectively. On the other hand, the dithio-bismaleimidoethane spacer led to variability on the molecular heights measured by tapping mode atomic force microscopy and the electrochemical response. This is interpreted in terms of lack of homogeneous dithio-bismaleimidoethane monolayer on gold. Furthermore, results from tapping mode atomic force microscopy show that the double mutant and the C62S did not lead to stably immobilized P450 protein, confirming the necessity of the solvent exposed C62.

Aromatase (CYP19A1), is a microsomal cytochrome P450 catalysing the conversion of androgens to estrogens. Non-steroidal inhibitors, such as anastrozole, are important drugs in breast cancer therapy. Using hyperfine sublevel correlation (HYSCORE) spectroscopy we provide the first experimental evidence of the binding of anastrozole to the iron heme of human aromatase.