Photocatalytic degradation of ibuprofen using titanium oxide: insights into the mechanism and preferential attack of radicals

The present work studied ibuprofen degradation using titanium dioxide as a photocatalyst. Mechanistic aspects were presented and the preferred attack sites by the OH˙ radical on the ibuprofen molecule were detailed, based on experimental and simple theoretical-computational results. Although some previous studies show mechanistic proposals, some aspects still need to be investigated, such as the participation of 4-isobutylacetophenone in the ibuprofen degradation and the preferred regions of attack by OH˙ radicals. The photodegradation was satisfactory using 0.03 g of TiO₂ and pH = 5.0, reaching 100% decontamination in 5 min. The zeta potential curve showed the regions of attraction and repulsion between TiO₂ and ibuprofen, depending on the pH range and charge of the species, influencing the amount of by-products formed. Different by-products have been identified by GC-MS, such as 4-isobutylacetophenone. Ibuprofen conversion to 4-isobutylacetophenone takes place through decarboxylation reaction followed by oxidation. The proposed mechanism indicates that the degradation of ibuprofen undergoes a series of elementary reactions in solution and on the surface. Three different radicals (OH˙, O₂⁻˙ and OOH˙) are produced in the reaction sequence and contribute strongly to the oxidation and mineralization of ibuprofen and by-products, but the hydroxyl radical has a greater oxidation capacity. The simple study using the DFT approach demonstrated that the OH˙ radical attacks preferentially in the region of the ibuprofen molecule with high electronic density, which is located close to the aromatic ring (C C bond). The presence of the OH˙ radical was confirmed through a model reaction using salicylic acid as a probe molecule.

The degradation of ibuprofen undergoes a series of elementary reactions, generating different radicals which attack preferentially in the region of the ibuprofen with high electron density.     

Distress levels in patients undergoing chemotherapy in Brazil

Objective: The objective of this study was to measure distress at three points during the course of chemotherapy: beginning, middle, and the last day of therapy in a private cancer center in Brazil. Methods: One hundred patients were assessed at three points during chemotherapy using the Distress Thermometer (DT) and the Hospital Anxiety and Depression Scale (HADS). The data were analyzed with the support of SPSS 15.0 software. Results: At the beginning of chemotherapy, patients mean scores were distress (82%), anxiety (78%) and depression (55%). In the middle of treatment, the percentages of distress, anxiety and depression decreased to 36.4, 25 and 25.3%, respectively. On the last day, the levels were 18.2% for distress and 14.3% for both anxiety and depression. Conclusion: Distress is highest in these patients at the beginning of chemotherapy, suggesting that evaluation of patients for psychosocial needs is important. Screening with a simple rapid instrument such as the DT is feasible and useful. Copyright © 2010 John Wiley & Sons, Ltd.     

Adequacy and Diagnostic Accuracy of Aspiration vs. Capillary Fine Needle Thyroid Biopsies

Thyroid nodules can be biopsied by fine needle aspiration (FNA) or fine needle capillary (FNC) biopsies. However, there is controversy on whether one technique is superior to another. In a randomized cytopathologist-blinded cross-sectional study, 260 patients (238 females, age 43.2 ± 12.6) with nodular (82.7%) and diffuse goiter (17.3%) underwent 520 FNAs and 520 FNCs (not guided by ultrasound). Smears were scored for sample adequacy, and diagnosed as malignant, benign, suspicious, or nondiagnostic. Diagnostic accuracy was calculated based on the histological findings of 58 patients submitted to surgery. Intra-technique diagnostic accuracy and sample adequacy was seen in all samples. FNA and FNC provided similar cytological diagnosis, respectively (benign: 75.8% vs. 74.2%, p = 0.600; malignant: 3.8% vs. 3.8%, p = 0.871; suspicious: 10.4% vs. 10.8%, p = 0.913; and nondiagnostic: 10.0% vs. 11.2%, p = 0.598). Adequacy scores were similar by FNA (7.94 ± 2.84) and FNC (7.96 ± 2.81, p = 0.909). The same proportion of adequate or superior samples was seen in both techniques (91.6%). Sensitivity was equal to 85.7% for FNA and 100% for FNC. Similarly, specificity was 100% for both techniques. FNA and FNC provide the similar sample adequacy and diagnostic accuracy. The choice of technique should be based on the operator’s personal preferences and experience.     

Pressure-suit combined with pelvic stop-flow: a feasibility study in a bovine model.

BACKGROUND: Isolated pelvic perfusion exposes tissue to high drug doses and may benefit patients with advanced malignancy. However, leakage is a limit to this technique. AIMS: The aim of the study is to increase the perfusion ratio between local and systemic compartments on isolated pelvic perfusion. We hypothesised that an inflated pressure-suit placed above the level of aortic and caval stop flow could decrease leakage from the regional to the systemic blood compartment in a bovine model. METHOD: As the size of the pressure-suit was adapted for use in humans, we performed our experimental study on 6 calves which are big enough to fit into the suit. We used an inflated pressure-suit placed at low (40mmHg) and high pressures (125mmHg) above the level of aortic and caval stop-flow. A pharmacokinetic study with cisplatinum was performed in both compartments. RESULTS: After injection of the drug, the mean ratio of drug concentration in the locoregional/systemic compartment was 43.1. After 30min, this mean ratio was 4 and 9.7 for a pressure-suit pressure of 40mmHg and 125mmHg, respectively. At pressure-suit pressures of 40mmHg and 125mmHg, pelvic perfusion achieved pelvic/systemic exposure ratios of 5.9 and 14.9 at 30min, respectively. Leakage at 30min was higher when the pressure-suit was inflated at low pressure (40mmHg, mean 18%). When the pressure-suit was inflated at high pressure, leakage was lower (125mmHg, mean 7%). CONCLUSIONS: The pressure-suit increased the perfusion ratio between pelvic and systemic compartments in a bovine model.     

Genotoxic effects of aluminum chloride in cultured human lymphocytes treated in different phases of cell cycle.

Aluminum (Al) is the most abundant metal and the third common chemical element on earth. It is known that Al is toxic, especially its trivalent form (Al(3+)), that represents the its most soluble form. Al intoxication is related to some pathogenic disorders, principally neurodegeneratives ones as Parkinson and Alzheimer diseases. The present study aimed to evaluate the mutagenic potential of aluminum chloride (AlCl(3)). Comet assay and chromosome aberrations analysis were applied to evaluate the DNA-damaging and clastogenic effects of AlCl(3), respectively, in different phases of the cell cycle. Cultured human lymphocytes were treated with 5, 10, 15 and 25 microM aluminum chloride during the G1, G1/S, S (pulses of 1 and 6h), and G2 phases of the cell cycle. All tested concentrations were cytotoxic and reduced significantly the mitotic index in all phases of cell cycle. They also induced DNA damage and were clastogenic in all phases of cell cycle, specially in S phase. AlCl(3) also induced endoreduplication and polyploidy in treatments performed during G1 phase. The presence of genotoxicity and polyploidy on interphase and mitosis, respectively, suggests that aluminum chloride is clastogenic and indirectly affects the construction of mitotic fuse in all tested concentrations.     

Epidemiological aspects of human papillomavirus infection and cervical cancer in Brazil

OBJECTIVES: A study was conducted to determine the prevalence of HPV infection in cervical lesions of Brazilian women and to search for specific risk factors associated to progression to malignancy. METHODS: Five hundred and fourteen paraffin-embedded biopsies obtained from female cervical lesions were classified according to the Bethesda System in low grade squamous intraepithelial lesion (LSIL), high grade SIL (HSIL) and squamous cell carcinoma (SCC). Specimens were tested for the presence of human papillomavirus (HPV) types 6/11,16/18 and 31/33/35 DNA using non-isotopic in situ hybridization. RESULTS: HPV prevalence ranged from 85.6% in LSIL to 55.2% in SCC. Patients were analysed through an 8 year period: 27. 1% of the lesions spontaneously regressed while 43.6% persisted and 29.3% progressed to carcinoma. High risk types were present in 80.5% (Crude OR 13.8, P=0.0003) of the progressive lesions. Possible co-factors have also been evaluated: history of other sexually transmitted diseases, mainly syphilis, showed to be positively related to progression (Adjusted OR 13.0, P=0.0003) while oral contraceptive use and tobacco smoking were not significantly related to it (P>O.1). Association of two or more co-factors also proved to be related to progression. CONCLUSIONS: Oncogenic HPV types 16 and 18 and history of other concurrent sexually transmitted diseases were found to be significantly associated with progression to cancer. Smoking and the use of oral contraceptives did not show a relation to cancer establishment, but when they were associated a significant co-operative role in progression was demonstrated. Our study indicated that HPV and other risk factors for cancer can act together, corroborating the observation of a poor prognosis for Brazilian women presenting SILs.