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T Lettini

Publications and source records attributed to T Lettini.

At least 19 recordsLinked to original sources
PubMed2000

[Atypical meningioma: morphometric analysis of nuclear pleomorphism].

The revised edition of the WHO classification of brain tumours now includes the "atypical" meningioma (grade II) which should be placed between the common type (grade I) and anaplastic type (grade III) according to histomorphological features and prognosis. However, diagnostic criteria for atypical meningioma are vague and the significance of brain invasion in the determination of malignancy is controversial. Nuclear pleomorphism and mitoses are usually considered the most important parameters to distinguish atypical and malignant meningiomas. According to WHO classification we selected eight cases of meningioma diagnosed as atypical (3 cases) and malignant (5 cases). All the tumours were supratentorially located. Nine cases of benign meningiomas were also studied as a control group. Morphometrical analysis was carried out by S.A.M. (Shape Analytical Morphometry) system. S.A.M. logical architecture assumes that each irregular shape contains elements of two distinct logical domains: gross distortions that interest the contour and its local perturbations. These features were investigated separately by analytical procedures to acquire independent parameters both on the logical and the numerical level. The results, statistically evaluated, show that nuclear pleomorphism is not a satisfactory criterion, if used alone, to distinguish atypical from malignant meningioma (Discriminant Analysis: 19% of minimum error).

Brain Neoplasms↗
PubMed2000

Real-time quantification of the proliferative state in astrocytomas.

OBJECTIVE: To evaluate proliferative activity in a set of gliomas and to compare the quantitative data obtained by a real-time processor with the labelling index (LI) and mitotic index (MI). STUDY DESIGN: Ki-67 immunostaining was performed on paraffin-embedded specimens from 42 cases of glioblastomas, 17 cases of anaplastic astrocytomas and 14 cases of low grade astrocytomas. Nuclear positivity was calculated as LI and by a real-time image processor for quantitative evaluation. MI was also calculated at 10 high-power fields. The data obtained from glioblastomas were compared with those from anaplastic and low grade astrocytomas. To all the data was applied the Pearson test to verify the correlation between counting and quantitative values and between proliferative markers and survival. RESULTS: A positive trend from low grade astrocytomas to glioblastomas was found for Ki-67 (LI and quantitative values) and MI, with highly significant differences between the three grades of gliomas considered. A good correlation between LI and quantitative values of Ki-67 was found. Very little relationship resulted between survival and Ki-67 LI. No relationship was found between survival and quantitative values of Ki-67. CONCLUSION: Ki-67 allowed effective separation of astrocytic tumors with different grades of malignancy. Quantitative evaluation of color information by means of a real-time processor proved to be a useful, objective and fast way to obtain readings, useful for grading purposes but not for prognostic evaluation.

Astrocytoma↗
PubMed1998

Somatostatin expression in TS16 mouse brain cultures.

Somatostatin expression in trisomy 16 mouse neuronal cultures has been studied to investigate the effects of the presence of an extra copy of the pre-pro-somatostatin (ppSS) gene on mouse chromosome 16. The immunoreactivity for somatostatin (SS) was considered in mixed cultures of neurons and glia cells and in neuron-enriched cultures as well as that for neuropeptide Y, glutamic acid decarboxylase, and gamma-enolase immunoreactivity the genes of which are not present on mouse chromosome 16. ppSS and pre-pro-neuropeptide Y (ppNPY) mRNA expression was evaluated and SS immunoreactivity in neurons analyzed by a morphometrical study. The extra copy of the ppSS gene resulted in a significantly increased level of the transcript in trisomic cultures, whereas the expression of the other neuropeptides did not differ. The absence of glial cells in these cultures reduced the number of SS-positive neurons making their number comparable in the trisomic and control cultures. Thus, in spite of higher expression of the ppSS mRNA in trisomic cultures, the determination of this peptidergic phenotype was influenced by the presence of neuroglial cells.

Animals↗
PubMed1997

[Malignant mesothelioma of the pleura. Morphometric study].

Malignant mesothelioma is difficult to distinguish from other pleural malignancies and also from benign mesothelial lesions. A morphometric study has been performed to distinguish between them using quantitative size and shape parameters. Seven cases of malignant mesothelioma, 5 cases of pleural metastatic adenocarcinoma and 4 cases of benign mesothelial lesions were selected and subjected to S.A.M. (Shape Analytical Morphometry). The results, statistically evaluated, showed that morphometric parameters can be proposed for diagnostic purposes being useful in the discrimination among the three populations. In fact, multivariate discriminant analysis (MDA) of the quantitative parameters obtained by morphometrical study distinguished the three groups of lesions with only 2% of error between BML/MM, 7% of error between BML/MA and 25% between MM/MA.

Adenocarcinoma↗
PubMed1996

Nuclear morphometry in squamous cell carcinoma (SCC) of the tongue.

In the histological grading of oral squamous cell carcinoma (OSCC) nuclear features are very important. Nevertheless evaluation is usually performed in a subjective and not highly reproducible way. The aim of this work was to investigate the relationship between nuclear shape and survival in 30 cases of carcinoma of the tongue. All the patients were divided into two groups: short-term survival and long-term survival. Twenty nuclei for each tumour were submitted to a morphometrical study by the shape analytical morphometry (SAM) software system. It was thus possible to evaluate not only nuclear dimensions but also nuclear contour irregularities and nuclear shape asymmetries. Multivariate discriminant analysis (MDA) of the quantitative parameters obtained by the morphometrical study distinguished the patients of the two groups with only a 10% error; moreover successful cluster analysis was performed by using Fourier parameters. Both these sets of results were achieved mainly owing to the parameters for contour irregularities.

Adult↗
PubMed1996

Nuclear morphometry in node-negative breast carcinoma.

OBJECTIVE: To determine whether nuclear morphometry can confirm or add useful information to classic clinicopathological prognosticators to identify the subpopulation of breast carcinoma patients with node-negative (N-) disease, at high risk of disease relapse. STUDY DESIGN: On the basis of results obtained by clinicopathologic evaluation of a group of patients with N- breast cancer, on a test group of 56 cases (32 patients disease free and 24 with relapse), we performed a morphometric analytical study of nuclei using the Shape Analytical Morphometry (SAM) software system; 20 nuclei for each case and 17 morphometric parameters for each nucleus were analyzed. RESULTS: The SAM system allowed us to quantify shape differences in nuclei in terms of contour irregularities and asymmetries along with evaluation of nuclear dimensions. Dimensional and analytic parameters were subjected to univariate (Student's t test) and multivariate (Hotelling's test) analysis. Multivariate discriminant analysis showed that an exact forecast of disease relapse could be made in 77% of patients with N- breast cancer by using a set of six both analytic and dimensional parameters. CONCLUSION: These results confirm that nuclear pleomorphism is the result of both contour irregularities and shape asymmetries and that even though they should be considered preliminary results, they stress the importance of quantitative shape evaluation.

Breast Neoplasms↗
PubMed1994

Size and shape evaluation of astrocytoma nuclei with the shape analytical morphometry software system.

Eighteen cases of astrocytomas diagnosed as grades 1-3 of malignancy were studied with analytical morphometry to determine if different grades can be discriminated by size and shape parameters related to the nuclei. The shape analytical morphometry system was used to calculate dimensional measurements and express shape irregularities through quantitative parameters. With the shape asymmetry evaluator procedure, nuclear symmetry was evaluated. All parameters subjected to univariate and multivariate strategies were the same in easily distinguishing grade 1 from the others. Grades 2 and 3 could not be discriminated completely by either dimensional or with analytical parameters revealing strong similarities of nuclear shape and dimensions.

Astrocytoma↗
PubMed1992

Morphometrical investigation of medulloblastoma nuclei by S.A.M. (Shape Analytical Morphometry) software system.

In order to characterize medulloblastomas and to get over the difficulties sometimes encountered in differential diagnosis, a double morphometric procedure has been applied to its nuclei. The first consisted of size measurements (maximum diameter, area and perimeter), the latter is represented by S.A.M. (Shape Analytical Morphometry) software-system specifically implemented to describe shape of biological structure by analytical parameters. Analytical and dimensional parameters submitted to Hotelling's multivariate discriminant analysis gave the best results when used together in convenient discriminant subsets, thereby allowing a good distinction between medulloblastoma in comparison with neuroblastoma, Ewing's tumor, lymphoblastic and lymphocytic lymphoma. These results underline the usefulness of morphometric characterization also for practical diagnostic purposes.

Cell Nucleus↗
PubMed1992

Biological image analysis for microscopical diagnosis: the work-station S.A.M. (Shape Analytical Morphometry).

The S.A.M. (Shape Analytical Morphometry) software system and its related work-station give a generalized and easy-to-handle tool to face a classic and intriguing problem in biomedical morphological diagnosis. What is the shape of an object in a microscopic image? How can we understand the relationship between size and shape? According to Holloway: "Measurements such as length, width, height, whether in chords or arcs only describe space, ... and further run into the abyss of allometric correction ... if additional information (shape?) to size is expected, some method of allometric correction must be used." The S.A.M. software system assumes a logic architecture able to separate and to parametrize independently shape characteristics in terms of allometry and local pertubation by analytical procedures (polynomials, parabolic fitting, Fourier analysis) in addition to the classic evaluations of size and density carried out by image analyzers for microscopical diagnosis.

Diagnosis, Computer-Assisted↗
PubMed1990

[Quantitative evaluation of the allometric transformation of of biological structures].

Detection and quantification of allometry is a crucial problem in understanding morphological changes, both for systematic and morphogenetic purposes. A section of S.A.M. (Shape Analytical Morphometry) software system was used for this attempt. It consists of the following steps: a) boundary detection; b) starting point detection; c) size normalization; d) extraction of the fundamental shape by Kth order polynomials; e) finding of symmetry evaluator (S.A.E.) by means of a second degree equation. This last procedure gives an arc-chord complex that expresses a vector for allometry where intercept value was for application point, first degree coefficient was for direction and second degree coefficient was for modulus and versus. The main parameters, isometry fraction and allometry fraction may be understood referring them to morphogenetic models.

Algorithms↗
PubMed1989

Relation between primary tumor shape and biological behavior in breast cancer.

The aim of this study was to investigate the biological significance of tumor shape in breast cancer by considering the shape not as a casual event but as an expression of the behavior and natural history of the tumor. The shape was studied by an analytical morphometry procedure and was related to axillary metastases, which up to now are the most meaningful prognostic factors in this disease. Fifty cases of infiltrating breast carcinoma (25 N+ and 25 N-) were investigated. The shape, studied on subgross sections of the tumor, was considered as the result of two components: the subtle contour irregularities and the main distortions of the figure. The procedures used allowed us to distinguish and to parametrize these two components in order to submit them to univariate analysis (Student's t test), a principal components analysis and, finally, a multivariate discriminant analysis (Hotelling test). The utilized analytical procedures by work-station S.A.M. (S.A.M. work station is a product of "Metamorphosis") consisted of three steps: 1) Extraction of tumor function curve obtained by Kth order polynominals which gives a smoothing effect to the original curve; 2) Evaluation of contour irregularities by Fourier harmonic analysis; 3) Evaluation of shape asymmetry by SAE (shape asymmetry evaluator). We considered also the roundness factors of the original and function curves and finally the maximum tumor diameter. Three parameters relating to contour irregularities (sum and mean value of Fourier harmonic amplitude and percentage of superimposed points) and parameters relating to main distortions of the figure (mean value of SAE) were highly significant (p less than 0.001). The roundness factor of the original curve was more significant (p less than 0.001) than that of the function curve (p less than 0.01) whereas maximum tumor diameter was not significant when tested by Student's t test. Multivariate discriminant analysis allowed 20% of error to be reached by using 3 parameters relating to the shape analysis and the two roundness factors. By using 8 parameters, including maximum tumor diameter, the percentage error was 16%. The results obtained, while they stress the usefulness of the employed procedure, reveal that shape of the tumor, together with its dimensions, is an important expression of the biological behavior relating to metastatic spread.

Analysis of Variance↗
PubMed1989

Hand-mirror (HM) cells in acute lymphoblastic leukaemia (A.L.L.). An attempt at cellular classification by morphometric analytical parameters using the S.A.M. (Shape Analytical Morphometry) system.

A morphometric study of the nuclear and cytoplasmic shape of a blastic population in a case of HM-A.L.L. was performed by comparing the two differently shaped populations with and without HM configuration. The results obtained using analytical size-independent parameters created by the S.A.M. work-station enable us to characterize the shape of both blastic cell populations quantitatively, and strongly suggest the existence of shape modulation from one cellular type toward the other. Thus a possible sequence from blastic cells (having regular, rather round nuclei) to HM cells (characterized by high distortion of both nucleus and cytoplasm) was proposed.

Cell Nucleus↗
PubMed1989

Non-Hodgkin's lymphoma diagnosis aided by the S.A.M. system.

In the attempt to discriminate between centroblasts and immunoblasts, an analytical morphometrical procedure was adopted, considering the nuclei of a randomly selected centroblastic and immunoblastic population from non-Hodgkin's lymphomas and the nucleoli of a more restricted number of the same neoplastic population. All the size-independent shape-descriptor parameters extracted for each step of the mathematical analyses used were submitted to Hotelling's multivariate discriminant analysis that enabled us to achieve a good distinction (3% error) between centroblasts and immunoblasts when nuclear and nucleolar parameters were used together.

Cell Nucleus↗
PubMed1985

[Parameters of analytic morphometry: proposal for a symmetry evaluator].

A morphometrical analytical evaluator of asymmetries of biological structures bonded by a closed curve was suggested. A second degree equation couple was found in order to detect, respectively according X and Y axis, first main asymmetry whereas third degree equation revealed first and second asymmetry for both abscissa and ordinate values. Final evaluator, named S.A.E. (Shape Analytical Evaluator), was computed as arch/cord ratio between function curve and its cord, it was equal to 1 for circles and any ellipse and symmetrical shapes whereas it was of different value for asymmetrical shapes.

Anthropometry↗
PubMed1984

[Fourier harmonic analysis of the sagittal profile of the Plesianthropus transvaalensis (STS5) skull].

An analytical morphometrical investigation of fronto facial profile of Plesianthropus transvaalensis was carried out by means of Fourier spectral series. Amplitude of contributors was evaluated in comparison with harmonic sets of a modern skull and two "mosaics" obtained by a convenient merging of segments of modern and hominid skull profiles. Patterns are distinctly different in Plesianthropus and modern profile because amplitude of second harmonic is greater than first in the former and viceversa in the latter; moreover while in Plesianthropus first and second harmonic give the same phase, it does not occur for modern skull. Fourier series of "mosaic" obtained by frontal profile of Plesianthropus and facial profile of modern resembles the set of modern skull while "mosaic" of modern frontal profile and hominid facial one resembles closely pattern of Plesianthropus.

Animals↗