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Antonio Cavallo

Publications and source records attributed to Antonio Cavallo.

5 recordsLinked to original sources
PubMed2002

Subwavelength size determination by spatially modulated illumination virtual microscopy.

A new approach for determining the sizes of individual, small fluorescent objects with diameters considerably below the optical resolution limit is described in which spatially modulated illumination (SMI) microscopy and 360-647-nm excitation wavelengths are used. The results of SMI virtual microscopy computer simulations indicate that, in this wavelength range, reliable measurements of sizes as small as approximately 20 nm are feasible if the low numbers of fluorescence photons that are usually detected from such small objects are taken into account. This method is based on the well-known fact that the modulation of the diffraction image in a SMI microscope is disturbed by the size of the object. Using appropriately calculated calibration functions, one can use this disturbance of the modulation to determine the size of the original object.

Journal Article↗
PubMed2002

Spatial preservation of nuclear chromatin architecture during three-dimensional fluorescence in situ hybridization (3D-FISH).

3D-FISH has become a major tool for studying the higher order chromatin organization in the cell nucleus. It is not clear, however, to what extent chromatin arrangement in the nucleus after fixation and 3D-FISH still reflects the order in living cells. To study this question, we compared higher order chromatin arrangements in living cells with those found after the 3D-FISH procedure. For in vivo studies we employed replication labeling of DNA with Cy3-conjugated nucleotides and/or chromatin labeling by GFP-tagged histone 2B. At the light microscope level, we compared the intranuclear distribution of H2B-GFP-tagged chromatin and the positions of replication-labeled chromatin domains in the same individual cells in vivo, after fixation with 4% paraformaldehyde, and after 3D-FISH. Light microscope data demonstrate a high degree of preservation of the spatial arrangement of approximately 1-Mb chromatin domains. Subsequent electron microscope investigations of chromatin structure showed strong alterations in the ultrastructure of the nucleus caused mainly by the heat denaturation step. Through this step chromatin acquires the appearance of a net with mesh size of 50-200 nm roughly corresponding to the average displacement of the chromatin domains observed at light microscope level. We conclude that 3D-FISH is a useful tool to study chromosome territory structure and arrangements down to the level of approximately 1-Mb chromatin domain positions. However, important ultrastructural details of the chromatin architecture are destroyed by the heat denaturation step, thus putting a limit to the usefulness of 3D-FISH analyses at nanometer scales.

Carbocyanines↗
PubMed2002

Stage I non-small cell lung carcinoma: really an early stage?

OBJECTIVE: We review our results on surgical treatment of patients with stage I non-small cell lung carcinoma and we attempted to clarify the prognostic significance of some surgical--pathologic variables. METHODS: From 1993 to 1999, 667 patients received curative lung resection and complete hilar and mediastinal lymphadenectomy for non-small cell lung cancer. Of these, there were 436 Stage I disease (65%), of whom 144 T1N0 and 292 T2N0. No patients had pre- or postoperative radio- or chemotherapy. Prognostic significance of the following independent variables was tested using univariate (log-rank) and multivariate (Cox proportional-hazards) analysis: type of resection (sublobar vs lobectomy vs pneumonectomy), histology (squamous cell vs adenocarcinoma), tumour size ( 3cm), histologic vascular invasion, visceral pleura involvement, positive bronchial resection margin, general T status. RESULTS: Overall 5-year survival was 63%. In both univariate and multivariate survival analysis, significant prognostic factors were histology (adenocarcinoma 65% vs squamous cell carcinoma 51%), tumour size ( 3cm 46%), and the presence of negative resection margin. Five-year survival by general T status was 66% in T1N0 vs 55% in T2N0 disease (P=0.19). CONCLUSIONS: Despite advances in early diagnosis and surgical technique, 5-year survival of stage I non-small cell lung carcinoma remains low as compared to survival of other solid organ neoplasm. Tumour size <or=3cm, adenocarcinoma histologic type and negative bronchial resection margins were associated with a more favourable outcome in our patient population. More effective multimodality treatments are needed to increase survival rates.

Carcinoma, Non-Small-Cell Lung↗