Biomedical subjects
Publications and source records attributed to P Calza.
In the comparison of formamide and urea photocatalytic degradation, despite their similar structures, the final fate of bound nitrogen under illumination with TiO2 has shown a different behaviour; both the rate and the ratio of NH4+ and NO3- ion evolution seem not to be linked to the initial nitrogen oxidation state, but to the carbon oxidation state.
A zeolitic material containing Ti chains activated by light allows a shape-selective transformation of organic compounds; the molecules that can enter into the zeolitic cavities are protected from the light-induced processes, while the other are degraded.
The photocatalytic transformation of dexamethasone and the formation of its intermediate compounds have been studied using titanium dioxide as a photocatalyst. The degradation of dexamethasone occurs easily through the formation of several hydroxy derivatives whose characterization has been made by HPLC/MS/MS. Even if both oxidative and reductive processes can be operating, only oxidative products have been identified in air saturated aqueous suspensions. A pattern of reaction pathways accounting for the observed intermediates is proposed. The obtained experimental evidence may be rationalized postulating the existence of a double initial mechanism. A single oxidation step resulting from the attack by one *OH radical leading to the formation of five hydroxy-derivatives and a concomitant attack involving two *OH radicals leading to the hydroxylation of the quinoid moiety of the molecule.
INTRODUCTION: Axillary lymph node dissection (ALND) represents an important staging procedure in the surgical treatment of breast cancer. However, it may result necessary in tumors of little dimensions because of low percentage of metastatic axillary lymph node (ALN). If a non invasive technique predicted the status of ALN, ALND procedures could be avoided. We carried out this study i) to establish the best technique to perform the lymphoscintigraphy for detecting the sentinel node in breast cancer and ii) to determine whether a clear sentinel node reliably predicts a disease free axilla. METHODS: 215 patients were submitted to the lymphoscintigraphy before surgery. Three different colloidal radiotracers with particle size ranging between < 50 and 1000 nm were injected sudermically or peritumorally. Early and late images were recorded in anterior and oblique projections and the SN was marked on the skin and biopsied using a gamma detection probe (GDP) during surgery. RESULTS: The SN was identified in 210/215 cases (97.6%). The SN accurately predicted axillary ALN status in 204/210 (97.1%) patients in whom a sentinel node was identified and in all the cases (45 patients) with tumor < 1.5 cm in diameter. In 38/101 cases with metastatic axillary nodes (37.7%) the only positive node was the SN. CONCLUSIONS: Lymphoscintigraphy can easily locate the SN in breast cancer. SN detection resulted easier when large size microcolloids were used. Subdermally administration appeared the best way of injection for palpable lesions. Breast cancer patients without clinical involvement of the axilla should undergo SN biopsy routinely and this may allow sparing complete axillary dissection when the SN is free of disease.
UNLABELLED: Lymphoscintigraphy associated with radioguided biopsy of the sentinel node (SN) is well established in clinical practice for melanoma. In breast cancer, the SN concept is similarly valid, and lymphoscintigraphy is a useful method for localizing the axillary SN. The aim of this study was to optimize the lymphoscintigraphy technique in association with a gamma ray detecting probe (GDP) for identifying and removing the SN in breast cancer patients. METHODS: Two-hundred fifty patients with operable breast tumor underwent lymphoscintigraphy before surgery. Three different size ranges of 99mTc-labeled colloid particles (<50, <80 and 200-1000 nm) were used, with either subdermal (above tumor) or peritumoral injection. Early and late scintigraphic images were obtained in anterior and oblique projections, and the skin projection of the detected SN was marked. Sentinel nodes were identified and removed with the aid of the GDP during breast surgery; they were tagged separately. Complete axillary dissection followed. In 40 patients, a blue dye was also administered in addition to subdermal radiolabeled colloid to compare blue dye mapping with lymphoscintigraphy localization. RESULTS: Lymphoscintigraphy successfully revealed lymphatic drainage in 245 of 250 patients (98%). The axillary SN was identified in 240 patients (96%). SN biopsy correctly predicted axillary node status in 234 of 240 patients (97.5%). Lymphoscintigraphy and GDP detected the SN most easily and consistently when 200-1000 nm colloid was administered subdermally in an injection volume of 0.4 ml. Blue dye mapping was successful in 30 of 40 patients (75%). In 26 of these patients, the dye and lymphoscintigraphy identified the same node; in 4 cases different nodes were identified. None of these four patients had axillary disease. CONCLUSION: Lymphoscintigraphy is a simple procedure that is well tolerated by patients. Sentinel node identification is more reliable when large-size radiolabeled colloids are injected in a relatively small injection volume (0.4 ml). Use of a GDP greatly facilitates precise pinpointing and rapid removal of the SN.