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T Megha

Publications and source records attributed to T Megha.

33 records · Page 2Linked to original sources
PubMed1995

Presence of the bcl-2 protein and apoptosis in non-Hodgkin lymphomas with diffuse growth pattern.

In an attempt to further clarify the role of the apoptosis-counteracting protein bcl-2, non-Hodgkin lymphomas (NHL, n = 170) were examined immunohistochemically, across the boundaries of histologic classification, for the presence of this oncoprotein, in comparison with apoptotic indices (AI) and percentages of Ki-67+ cells (growth fraction). The results of this retrospective study revealed a highly significant inverse relationship ("mirror image") between the proportion of bcl-2+ cells and the AI per case. Both these parameters, although variable, clearly distinguished low- from high-grade-malignancy lymphomas according to the Kiel classification. Cluster analysis detected 2 separate groups of high-grade NHL, one with rather high AI and low percentages of bcl-2+ cells, comprising most anaplastic large-cell lymphomas, the other group with reverse characteristics. We found no correlation between the percentage of bcl-2+ cells per case and overall survival.

Apoptosis↗
PubMed1995

Low versus high cell turnover in diffusely growing non-Hodgkin's lymphomas.

Cell loss, perhaps as important as cell production in determining the size of an expanding cell population, has not usually been registered in quantitative cellular kinetic analyses of neoplastic disorders. The present retrospective study on various types and subtypes of non-Hodgkin's lymphomas (NHLs; n = 170) was designed to test the usefulness of a novel additional parameter, the 'turnover index' (TI), which is the sum per case of the mitotic index and the apoptotic index. Results document that TIs clearly distinguished between categories and subtypes of NHLs according to the Kiel classification. Cluster analysis of TIs plotted against the percentage of Ki-67-positive cells per case revealed that about one-third of the high-grade malignancy lymphomas actually belonged to the low-turnover lymphomas. Overall survival was longer in the low- than in the high-turnover group of lymphomas. Assessment of TIs can, for practical diagnostic purposes, be replaced by counting mitotic figures and apoptotic cells in several high-power fields. The TI concept may help to interpret the kinetics of NHLs in terms of accumulation vs. proliferation of cells.

Adolescent↗
PubMed1994

Spatial distribution of mitosis, apoptosis and small blood vessels in malignant diffuse follicular-center-cell lymphomas: a nearest-neighbor analysis.

To better comprehend the relationships between cell birth and cell death in neoplastic disorders, the topography of these events needs to be considered. We applied a computerized nearest-neighbor analysis to malignant, diffuse follicular-center-cell lymphomas in order to examine the spatial distribution of pyknotic (apoptotic) cells/bodies (A) and mitotic figures (M) in relation to capillaries (C) and venules (V). The results revealed a complex dispersion pattern, with significant aggregations of A and M, in addition to an even greater random distribution component. The greatest clustering displayed by A was around capillaries (A-C, 42% reduction of object frequency between the first and second distance class), followed by A-A (33%), A-V (24%) and A-M (12%). Additional values for mitotic figures were: M-M (45%), M-V (33%) and M-C (22%). These findings may reflect the relative importance of inherent properties of the neoplastic and host factors, respectively, in the regulation of cell birth and cell death rates.

Adult↗
PubMed1993

Epstein-Barr virus and gastric cancer: data and unanswered questions.

Sixty-five unselected cases of gastric cancer have been analysed for EBV DNA by polymerase chain reaction, in situ hybridization and immunohistochemistry for CD21 antigen expression. Four cases were found EBV-positive by PCR, while ISH yielded positive results in 3 of these cases, demonstrating EBV in the nuclei of cancerous cells. CD21 antigen was expressed in cancerous cells in all 3 ISH-positive cases. All the EBV-positive cancers of the present series were poorly to moderately differentiated adenocarcinomas with prominent lymphoid infiltration. These results are discussed also on the basis of the literature.

Adenocarcinoma↗
PubMed1993

Correlations between apoptotic and proliferative indices in malignant non-Hodgkin's lymphomas.

Cell production versus cell loss rates were estimated, across the boundaries of histological classification, in 50 cases of malignant non-Hodgkin's lymphomas by use of mitotic indices, percentage of Ki-67+ cells and percentage of PC10+ cells as proliferative indices, and the relative number of apoptotic bodies (apoptotic indices, AIs) as parameters. Regression analysis revealed significant (P < 0.01) positive correlations between the AIs and the proliferative indices; among the immunohistochemically assessed proliferative indices; and between these, the mitotic indices and the AIs on the one hand and histological malignancy grades on the other hand. The cellular protein BCL-2, which counteracts apoptosis, was significantly (P < 0.01) more often expressed in lymphomas with low than in those with high AIs. Multivariate analysis of data showed that of all parameters tested in this series, only the AIs correlated significantly (P < 0.05) with overall lethality. The correlation between BCL-2 positivity of lymphoma cells and overall survival did not quite attain significance (P = 0.08). Results of the present study suggest that high AIs and lack of BCL-2 expression may be adverse prognostic factors, independent of histological grade.

Apoptosis↗
PubMed1992

Pleural malignant mesothelioma in Tuscany, Italy (1970-1988): I. Anatomo-pathologic aspects.

Our investigation did not confirm the general experience that significant numbers of cases initially considered malignant mesothelioma or metastatic carcinoma are actually found to be metastatic carcinoma or malignant mesothelioma, respectively, upon deeper investigation using ancillary techniques (e.g., histochemistry, immunohistochemistry, electron microscopy). Well-trained pathologists, expert in thoraco-pulmonary pathology, have a high inter- and intra-rater agreement and significantly better results than standard hospital pathologists in correctly differentiating malignant mesothelioma from metastatic carcinoma. Therefore, epidemiologic investigations which exclude an accurate and rigorous reevaluation of the histologic slides have to be considered unreliable, unless the data come from a specialized medical center experienced in this type of pathology.

Adult↗
PubMed1991

Diffuse centrocytic and/or centroblastic malignant non-Hodgkin's lymphomas: comparison of mitotic and pyknotic (apoptotic) indices.

Mitotic indices (MIs) and pyknotic (apoptotic) indices (PIs) were assessed in diffuse centrocytic (CC, n = 10), centroblastic/centrocytic (CB/CC, n = 18) and centroblastic (CB, n = 20) malignant non-Hodgkin's lymphomas (NHL). Significant differences were observed. MIs were lowest in CC (median: 0.07%), intermediate in CB/CC (0.18%) and highest in CB (0.43%) NHLs. The PIs exhibited a similar pattern. The PIs of CC (0.11%) and CB/CC (0.17%) NHLs were significantly different from those of CB lymphoma (0.62%). The ratios MI/PI per case, as well as MIs and PIs per case, varied greatly and showed considerable overlapping, thus documenting a marked inter-case and inter-group heterogeneity. MIs tended to loosely correlate with PIs in a non-linear fashion, which raises the question of feedback mechanisms. More information is needed on mitotic time (TM) and apoptotic time (TA), in order to estimate cell doubling time from data on MIs and PIs.

Adult↗
PubMed1990

Morphometric definition and grading of gastric intestinal metaplasia.

Type I and type III intestinal metaplasia in gastric mucosa have been examined using morphometric methods. Tissue (volume per cent gland, lumen, epithelium, goblet cell vacuoles) and nuclear parameters (area, with related standard deviation, and form factors) were used as indicators of gland crowding, nuclear-cytoplasmic ratio, nuclear atypia, and pleomorphism. In type III intestinal metaplasia, there is significantly (i) greater nuclear pleomorphism, (ii) a higher nuclear-cytoplasmic ratio, and (iii) smaller and less numerous goblet cell vacuoles in both the upper and the lower parts of the crypts. These two parameters have significantly higher values in the lower than in the upper part of individual crypts. No cell population with large pleomorphic nuclei characterized type III metaplasia, though there was more variation in nuclear size.

Adult↗
PubMed1990

Hodgkin's disease and CD30-positive anaplastic large cell lymphomas--a continuous spectrum of malignant disorders. A quantitative morphometric and immunohistologic study.

The authors have examined cellular areas of lymphoma tissue in 28 cases of Hodgkin's disease (HD) or anaplastic large cell lymphoma (ALCL, 'Ki-1 cell lymphoma') to evaluate the boundaries between the two entities. Methods applied included conventional histology; test point analysis; semiautomated morphometry of nuclear profile features of Reed-Sternberg and other atypical large cells (RSALCs); and immunohistochemistry of these elements on all paraffin sections and, in 15 cases, on frozen sections. Mean nuclear profile morphotypes of RSALCs per case varied independently of immunophenotype and histologic diagnosis. Conversely, immunohistochemistry demonstrated significant, although not consistent, preferential positivities of these CD30+ elements for CD15 in HD, and for epithelial membrane antigen (EMA) and CD43 in ALCLs. In the latter, RSALCs also exhibited a tendency for CD45 and CD45RO positivity and for the expression of T-cell-associated antigens. However, there were considerable overlaps. This continuous spectrum of RSALC nuclear profile morphotypes and immunophenotypes, ranging from HD over questionable cases, intermediate between HD and ALCL, to ALCLs, was paralleled by differences in the reactive component of lymphomas. Lymphocytes and granulocytes were significantly deficient in ALCLs.

Adolescent↗
PubMedDate not supplied

Lack of association of insulin resistance and carotid intimal medial thickness in non-diabetic Asian Indian subjects.

OBJECTIVE: Atherosclerosis is associated with insulin resistance (IR) and dyslipidaemia. Impaired glucose tolerance (IGT) is characterised by IR and is associated with a higher risk of atherosclerosis. The objective of the present study was to test whether early atherosclerosis indicated by intimal medial thickness (IMT) of common carotid artery (CCA) and internal carotid artery (ICA) is higher in IGT than in normoglycaemic subjects (NGT) and to look for an association of IMT with IR and dyslipidaemia. STUDY DESIGN AND METHODS: Ninety-nine randomly selected non-diabetic subjects aged >or=35 years (48 NGT and 51 IGT) were studied. Measurements of body mass index (BMI), waist/hip ratio (WHR), blood pressure, cholesterol-total, HDL, LDL, VLDL, triglycerides (TG), lipoprotein (a), apolipoprotein-A1 (Apo A1) and apolipoprotein-B (Apo B) and ratio of Apo A1/Apo B were estimated. Insulin resistance (HOMA-IR) was calculated using the fasting plasma insulin and glucose values. IMT of CCA and ICA were measured using high-resolution beta-mode ultrasonography. RESULTS: Subjects with IGT and NGT were matched for BMI and WHR; HOMA-IR was higher in IGT vs NGT (7.92+/-4.2 vs 6.07+/-3.76, p = 0.028). Age-adjusted IMT values were similar in NGT and IGT (CCA 0.59+/-0.17 and 0.63+/-0.22 mm and ICA 0.44+/-0.10 and 0.45+/-0.10 mm, respectively). Further analyses were done in the total group. Multiple linear regression analyses showed that CCA-IMT was significantly associated with age and negatively associated with Apo A1/Apo B ratio. ICA-IMT was associated with age only. IMT was significantly correlated with cholesterol-total and LDL-cholesterol and apolipoproteins. It was not associated with IR. CONCLUSION: In southern Indians, IGT did not influence the IMT. Although insulin resistance was higher in IGT, it was not associated with higher IMT. Conventional risk factors such as cholesterol, LDL-cholesterol and apolipoproteins showed association with IMT in the insulin-resistant population.

Adult↗
PubMedDate not supplied

Hepatoid gastric carcinoma. A case report.

Alpha-fetoprotein (AFP) is normally produced by primary hepatic neoplasms and germ cell tumors. There have, however, been reports of its production in cases of gastrointestinal tract adenocarcinoma. Gastric hepatoid carcinomas constitute a clinicopathological entity of recent acquisition and have certain common characteristics, which include the presence of hepatoid foci and frequent liver metastases, even in cases of early gastric cancer, and increasing serum AFP levels. In this study the case of one patient who underwent gastric resection and presented clinical, humoral, histological and immunohistochemical characteristics typical of hepatoid gastric carcinoma is reported. More biological studies, as well as precise criteria for pathological definition and therapy, are still necessary for a better understanding of this pathology.

Adenocarcinoma↗
PubMedDate not supplied

Cellular kinetics and expression of bcl-2 and p53 in ductal carcinoma of the breast.

In this study, the expression of p53 (wild-type and mutated form) and bcl-2 in ductal carcinoma in situ (DCIS) and infiltrating ductal carcinoma (IDC) of the breast was evaluated by immunohistochemistry and PCR-SSCP and correlated with cellular kinetic parameters, i.e., mitotic index (MI) and apoptotic index (AI). The results showed a significant inverse correlation between p53 and bcl-2 expression in all cases of DCIS and IDC. In the DCIS group, two subgroups with different kinetic characteristics were identified. The first group was characterized by p53 positivity, bcl-2 negativity and high values of MI and AI; the other group was characterized by p53 negativity, bcl-2 positivity and low values of MI and AI. Conversely, in IDC some cases were p53 negative, bcl-2 positive and with high values of AI and MI, other cases were p53 positive, bcl-2 negative and with low AI and MI. Molecular biological analysis showed that p53 was wild-type in DCIS, while it was in the mutated form in IDC. These results suggest that in IDC mutated p53 contributes to a change in cellular kinetics and the selection of genetically aberrant cells, thereby favouring neoplastic progression. The coexistence of bcl-2 positivity and high AI could be explained by the presence of of apoptosis that work independently of bcl-2.

Adult↗
PubMedDate not supplied

Expression of the G2-M checkpoint regulators cyclin B1 and P34CDC2 in breast cancer: a correlation with cellular kinetics.

In this study, the expression of cyclin B1 and p34cdc2 in neoplastic and non-neoplastic breast lesions was evaluated by immunohistochemistry and quantitative analysis in relation to cellular kinetic parameters such as Mitotic Index (MI), Anatelophase Index (ATI), and Apoptotic Index (AI). The percentage of cyclin B1 and p34cdc2-positive cells was significantly higher in neoplastic glands than in their normal counterparts. This finding was paralleled by significantly higher values of MI, ATI, and AI in breast cancer than in normal glands. Furthermore, two groups with different cytokinetic characteristics were identified among infiltrating ductal carcinomas by an unsupervised learning technique of cluster analysis using the percentages of cyclin B1 and p34cdc2 positive cells and the cellular kinetic parameters (MI, ATI and AI) as variables. The final clusters, groups I and II, consisted of 42 and 13 cases respectively. The first cluster (group I) was characterized by a significantly linear correlation between the percentages of cyclin B1 and p34cdc2-positive cells. On the contrary, the second cluster (group II) revealed no correlation between these two proteins and was characterized by values of p34cdc2 largely exceeding those of cyclin B1. A positive correlation between the expression of these two proteins and the cellular kinetic parameters (MI, ATI and AI) was also found in group I but not in group II. These observations suggest that a disturbed nuclear translocation of Mitosis Promoting Factor (MPF) components is present in group II cases, resulting in a defective cellular division cycle. In fact, group I cases showed lymph node metastasis more frequently than group II cases. Our results suggest that the analysis of the cell cycle "machinery" components, such as the cyclins and their dependent kinases, can identify tumors with different levels of aggressiveness.

Adult↗