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M Bertero

Publications and source records attributed to M Bertero.

11 recordsLinked to original sources
PubMed2003

Super-resolution in computational imaging.

Super-resolution is a word used in different contexts but mainly in the case of methods aimed at improving the resolution of an optical instrument beyond the diffraction limit. Such a result may be achieved by means of specific instrumental techniques (such as, for instance, interferometry) or by means of a suitable processing of a digital image; in the latter case we will use the expression computational super-resolution (CSR). In this paper we describe the basic concepts underlying CSR without using the mathematics required for establishing its theoretical validity. The aim is to introduce a wide audience to this topic, to specify the situations where CSR is feasible and to emphasize the point that unlimited CSR is not possible.

Algorithms↗
PubMed2002

Experimental validation of a linear model for data reduction in chirp-pulse microwave CT.

Chirp-pulse microwave computerized tomography (CP-MCT) is an imaging modality developed at the Department of Biocybernetics, University of Niigata (Niigata, Japan), which intends to reduce the microwave-tomography problem to an X-ray-like situation. We have recently shown that data acquisition in CP-MCT can be described in terms of a linear model derived from scattering theory. In this paper, we validate this model by showing that the theoretically computed response function is in good agreement with the one obtained from a regularized multiple deconvolution of three data sets measured with the prototype of CP-MCT. Furthermore, the reliability of the model as far as image restoration in concerned, is tested in the case of space-invariant conditions by considering the reconstruction of simple on-axis cylindrical phantoms.

Computer Simulation↗
PubMed2000

Image restoration in chirp-pulse microwave CT (CP-MCT).

Chirp-pulse microwave computed tomography (CP-MCT) is a technique for imaging the distribution of temperature variations inside biological tissues. Even if resolution and contrast are adequate to this purpose, a further improvement of image quality is desirable. In this paper, we discuss the blur of CP-MCT images and we propose a method for estimating the corresponding point spread function (PSF). To this purpose we use both a measured and a computed projection of a cylindrical phantom. We find a good agreement between the two cases. Finally the estimated PSF is used for deconvolving data corresponding to various kinds of cylindrical phantoms. We use an iterative nonlinear deconvolution method which assures nonnegative solutions and we demonstrate the improvement of image quality which can be obtained in such a way.

Algorithms↗
PubMed1996

Low-dose integrated chemoimmuno-hormonotherapy with cisplatin, subcutaneous interleukin-2, alpha-interferon and tamoxifen for advanced metastatic melanoma--a pilot study.

Recently, Khayat et al. reported that high-dose recombinant interleukin-2 (rIL-2) i.v. may induce tumour regressions in metastatic melanoma patients through an association with cisplatin (CDDP) and alpha-interferon (alpha-IFN). Treatment-related toxicities are, however, important. Previous studies have demonstrated that rIL-2 toxicity may be reduced through a subcutaneous injection. In order to evaluate the effectiveness of low subcutaneous rIL-2 doses in a chemoimmuno-hormonotherapeutic combination, 36 metastatic melanoma patients were treated with CDDP, rIL-2, alpha-IFN and tamoxifen (TAM). The overall response rate was 47.2%: five patients had complete response (14%), 12 partial response (33%) and 13 stable disease (36%). Median response duration was 6.4 months (range: 2-29+). Median overall survival was 10 months (range: 3-36+). The CDDP/rIL-2/alpha-IFN/TAM regimen was effective both on soft tissue and visceral metastases. Toxicity was low and patient management did not require an intensive care unit. A statistically significant increase in both percentage and absolute values of lymphocytes, eosinophils, CD3+/CD4+, CD25+, CD16/56+ and HLA-DR+ cells was found in all patients after two treatment courses. This study shows that lower doses of subcutaneous rIL-2, as well as CDDP and alpha-IFN, associated with TAM, may have similar anticancer efficacy with respect to Khayat's schedule but lower toxicity.

Adult↗
PubMed1995

Adjuvant therapy of stage IIIb melanoma with interferon alfa-2b: clinical and immunological relevance.

BACKGROUND: The poor prognosis of stage IIIb melanoma (5-year survival: 36%) shows the need for effective adjuvant therapy to prolong disease-free survival. OBJECTIVE: The feasibility and efficacy of interferon alfa-2b (IFN-alpha) therapy in stage IIIb melanoma patients was investigated. METHODS: alpha-IFN was given at a dose of 3 MU i.m. three times a week to 50 patients. Clinical and immunological controls were carried out. RESULTS: The median follow-up was 43 months (range 5-84). Median survival was 43 months and median disease-free survival 39 months. Overall 5-year survival (62%) was higher than that reported in the literature to date. A significant increase of circulating CD56+ and DR+ lymphocytes after therapy was more evident in disease-free patients than in those with progressing disease. CONCLUSIONS: Adjuvant IFN-alpha therapy in stage IIIb melanoma patients is well tolerated and seems to increase survival. However, multicenter randomized trials are needed to confirm these preliminary findings.

Adult↗
PubMed1994

Mantle zone lymphoma: an immunohistologic study of skin lesions.

BACKGROUND: Mantle zone lymphoma (MZL) is a B-cell proliferation regarded as the follicular variant of intermediate lymphocytic lymphoma (ILL). Neoplastic small lymphoid cells proliferate as wide mantles around atrophic centers of benign appearance. OBJECTIVE: The clinical, histologic, and immunohistochemical features of four cases of MZL, heralded by cutaneous lesions, are described and correlated with the lymph node pattern. RESULTS: All specimens showed extensive nodules in the reticular dermis invading the subcutaneous tissue. They were mainly composed of a proliferation of small lymphocytes with slightly irregular nuclear contours and clumped chromatin, forming wide mantles around small atrophic germinal centers. Serial biopsy specimens in case 1 revealed evolution of the skin lesions from pseudolymphoma into MZL. Their immunohistochemistry was similar to that of lymph nodes and showed that the neoplastic cells were CD5+, CD20+, CD22+, CD25+, CD74+, Leu-8+, HLA-DR+, IgM+, IgD+ with restriction for the lambda light chain, CD10-, and CD71-, whereas the germinal center cells were polyclonal. In three cases many CD38+, PCA-1+ plasma cells were present both in the grenz zone and in bordering neoplastic nodules. The clinical course was chronic. The only death occurred from unrelated causes; one patient is still alive 17 years after onset. CONCLUSION: Skin lesions may be the only manifestation of MZL for an extended period. The differentiation between pseudolymphoma and other lymphoma subtypes is based not only on the histologic and cytologic features but also on the architecture, followed by immunohistochemical confirmation.

Adult↗
PubMed1994

Adhesion molecules in lymphomatoid granulomatosis.

The expression of some adhesion molecules of the integrin family and their ligands was investigated in skin biopsies from a patient with lymphomatoid granulomatosis (LG), who at onset presented cutaneous lesions followed by lung and brain involvement. The angiocentric and angiodestructive skin infiltrate consisted mainly of T helper 'memory' cells (CD2+, CD3+, CD4+, CD5+, CD7+, CD45RO+) with a variable expression of activation antigens (CD25-, CD38+, CD71+, HLA-DR+) and 20% Ki67+ (nearly all atypical cells). T cells highly expressed alpha 3 beta 1 and alpha 5 beta 1 integrins, along with integrins of the beta 2 family. A modification of the expression pattern in laminin and collagen IV and an increased expression of tenascin and fibronectin were also observed.

Cell Adhesion Molecules↗
PubMed1993

Therapy for metastatic melanoma: effective combination of dacarbazine, carmustine, cisplatin and tamoxifen.

Thirty-two patients with metastatic melanoma received combination chemotherapy and hormonal therapy. Treatment included Carmustine, Cisplatin, Dacarbazine and Tamoxifen (BCDT). The overall response rate was 47%: five patients had a complete response (16%), 10 patients had a partial response (31%) and two had no response (6%). The median survival for responders was 10 months (range 2-20). The BCDT regimen was equally effective against soft tissue and visceral metastases. Neither survival or response rate was modified by pretreatment with alpha-interferon (alpha-IFN). In agreement with the results of a recent randomized trial comparing the efficacy of Dacarbazine with that of Dacarbazine plus Tamoxifen, a better survival was found in women than in men: although the response rate was identical (47%), the median duration of response was higher for women. A fall in serum soluble IL-2 receptor (sIL-2R) levels after therapy was seen in responding patients, confirming the usefulness of this parameter in monitoring disease evolution.

Adult↗
PubMed1992

Thymopentin in Sézary syndrome.

BACKGROUND: Response to the treatment of Sézary syndrome (a cutaneous T-cell lymphoma) is poor. Since patients with this syndrome are elderly, aggressive chemotherapy is poorly tolerated and deep immunodepression may result in fatal opportunistic infections. Immunomodulating therapy seems important in the management of Sézary syndrome. PURPOSE: In a pilot study, we assessed the efficacy of thymopentin (TP-5), a synthetic pentapeptide, correlating clinical responses to the histologic and immunologic effects of the drug. METHODS: Twenty Sézary syndrome patients received 50 mg TP-5 intravenously three times a week for a mean time of 16.3 months. Skin and lymph node histology and immunohistochemistry, circulating lymphoid cell subpopulations, and soluble interleukin-2 receptors were evaluated before treatment and during follow-up. RESULTS: Eight complete remissions and seven partial remissions were obtained (75%). No change was observed in three patients, and disease progression was observed in two patients. The median duration of response was 22 months (complete remission, 25.5 months; partial remission, 14 months). Four-year survival probability was 53.9%. The responses were obtained when circulating Sézary cells were less than 2600/mm3. A significant reduction of CD4+ cells paralleled a CD8+ cell increase. An increase in NK cells (CD16+ and CD56+) was accompanied by significantly longer survival. Serum soluble interleukin-2 receptor values were a useful monitor of the clinical course and treatment. Loss of epidermotropism, reduction of Langherhans' cells, and HLA-DR+ keratinocytes were found. CONCLUSIONS: TP-5 is a potentially useful agent in the treatment of a subgroup of patients with Sézary syndrome; its activity seems to be mediated by an effect on a normal NK cell-like subpopulation. IMPLICATIONS: The biological and clinical role of this therapy in combination with conventional treatments will be the subject of future investigations.

Aged↗
PubMed1992

Soluble interleukin-2 receptor, CD4 and CD8 levels in melanoma: a longitudinal study.

Serum levels of soluble(s) interleukin-2 receptor (IL-2R), sCD4 and SCD8 were analysed in 227 melanoma patients, using a sandwich enzyme immunoassay. Different stages of the disease were considered, and a longitudinal study with a 2-year follow-up was performed. Mean values of sIL-2R were significantly higher than in normal controls in all stages and correlated with the disease progression. sCD8 increases with stage progression were less striking, while sCD4 values were always in the normal range. We conclude that sIL-2R measurement is a useful clinical parameter in monitoring disease evolution in melanoma.

Adult↗