Glucocorticoid and calcitonin receptor expression in central giant cell lesions: implications for therapy.

Central giant cell lesion is an uncommon benign jaw lesion, with uncertain aetiology, and variable clinical behaviour. Studies of molecular markers may help to understand the nature and behaviour of this lesion, and eventually may represent a target for pharmacological approaches to treatment. The aim of this study was to analyse the expression of glucocorticoid and calcitonin receptors in central giant cell lesions before and after treatment with intralesional steroid. Paraffin-embedded blocks from patients who underwent treatment with intralesional triamcinolone hexacetonide injections were stained immunohistochemically. Biological material from patients who underwent a surgical procedure after treatment were tested immunohistochemically. 18 cases (9 aggressive and 9 non-aggressive) were included. The difference in calcitonin receptor expression was not statistically significant between the aggressive and non-aggressive lesions and between the patients with a good response and those with a moderate/negative response to treatment. Glucocorticoid receptor expression in the multinucleated giant cells was higher in patients with a good response. It can be postulated that immunohistochemical staining for glucocorticoid receptors may provide a tool for selecting the therapeutic strategy. An H-score greater than 48 for glucocorticoid receptors in multinucleated giant cells predicted a good response in this study.

Phenotypical and molecular characterization of Microsporum canis strains in north-east Brazil.

AIMS: This study investigated the possible correlation between the phenotypical and genotypical characteristics of Microsporum canis isolated from cats and dogs in north-east Brazil. METHODS AND RESULTS: The mycological study was conducted by direct microscopic examination and by fungal culture. Polymerase chain reaction-restriction enzyme analysis and random amplification of polymorphic DNA techniques were used for the genotypical analysis. The morphological analysis showed a considerable diversity of colonies as well as different morphologies of conidia, despite the M. canis strains having been isolated under the same conditions. However, the molecular analysis showed that all analysed strains are genetically similar. CONCLUSIONS: This study, based on phenotypical and molecular analysis, evidences the wide spectrum of phenotypical variations in M. canis in contrast to the stable genotypes of such dermatophytes. SIGNIFICANCE AND IMPACT OF THE STUDY: The findings of this study indicate that M. canis isolated from cats and dogs with dermatophytosis in north-east Brazil may be clones, well adapted to the conditions of this region, despite M. canis showing different morphological features.

Genotoxic effects of rotenone on cultured lymphocytes

Rotenone is a heterocyclic compound widely used as an insecticide, acaricide and piscicide. Its toxicity is mainly caused by the inhibition of mitochondrial respiratory processes and ATP production, resulting in the generation of reactive oxygen species. Reactive oxygen species can interact with DNA, RNA and proteins, leading to cell damage, followed by death. We used the Comet assay, and we analyzed chromosome aberrations, in order to evaluate the genotoxic and clastogenic effects of rotenone on the different phases of the cell cycle. Cultured human lymphocytes were treated with 1.0, 1.5 and 2.0 microg/mL rotenone during the G1, G1/S, S (pulses of 1 and 6 h), and G2 phases of the cell cycle. Rotenone induced DNA damage and was clastogenic, but the clastogenicity was detected only with treatments conducted during the G1/S and S phases of the cell cycle. Rotenone also induced endoreduplication and polyploidy in treatments made during G1, while it significantly reduced the mitotic index in all phases of the cell cycle.

Oncocalyxone A from Auxemma oncocalyx lacks genotoxic activity in phytohemagglutinin-stimulated lymphocytes.

Inadequate doses or prolonged chemotherapy can be cytotoxic or genotoxic to cancer patients, increasing the risk for the development of a second cancer, particularly acute leukemia. The association between therapeutic and genotoxic properties of oncocalyxone A (Onco A), make cytotoxic tests (mitotic index and chromosomal aberrations) fundamental in the accompaniment of the effects of this active compound. Therefore, the aim of the present study was to determine the genotoxic action of Onco A in vitro, during different phases of the cell cycle, utilizing primary cultures of lymphocytes of healthy individuals. The results showed that Onco A is cytotoxic during the cell cycle phases G1, G1/S, and S, however, not in G2. Onco A did not demonstrate a genotoxic effect in any of the cell cycle phases at the concentration studied. It is concluded that during the period of exposure, this active substance inhibits DNA synthesis and consequently cell division. Therefore, the absence of such genotoxicity for Onco A in the tests performed in this study provides important information in regard to the therapeutic use of this agent. Further studies are necessary to better understand the molecular mechanism of action of Onco A.

Oncocalyxone a from auxemma oncocalyx lacks genotoxic activity in phytohemagglutinin-stimulated lymphocytes

Inadequate doses or prolonged chemotherapy can be cytotoxic or genotoxic to cancer patients, increasing the risk for the development of a second cancer, particularly acute leukemia. The association between therapeutic and genotoxic properties of oncocalyxone A (Onco A), make cytotoxic tests (mitotic index and chromosomal aberrations) fundamental in the accompaniment of the effects of this active compound. Therefore, the aim of the present study was to determine the genotoxic action of Onco A in vitro, during different phases of the cell cycle, utilizing primary cultures of lymphocytes of healthy individuals. The resultsshowed that Onco A is cytotoxic during the cell cycle phases G1, G1/S, and S,however, not in G2. Onco A did not demonstrate a genotoxic effect in any of the cell cycle phases at the concentration studied. It is concluded that during the period of exposure, this active substance inhibits DNA synthesis and consequently cell division. Therefore, the absence of such genotoxicity for Onco A in the tests performed in this study provides important information in regard tothe therapeutic use of this agent. Further studies are necessary to betterunderstand the molecular mechanism of action of Onco A.

Chromosomal duplication accompanies allelic loss in non-small cell lung carcinoma.

Hemizygous deletion in the short (p) arm of chromosome 3 is a common finding in non-small cell lung carcinoma (NSCLC) and is postulated to be a crucial early change in lung tumorigenesis. Yet one of the most frequent nuclear abnormalities in both NSCLC and premalignant bronchial epithelium is increase in chromosomal copy number. Deletion and duplication have not been assessed in the same tumor set by both molecular and cytogenetic methods to determine whether allelic loss correlates with chromosomal duplication in the same tumor cell populations. It is also not established what biological mechanisms might lead to allelic deletion and chromosomal duplication. We have investigated changes in the copy number of chromosome 3 in touch preparations of 38 NSCLCs (19 adenocarcinomas and 19 squamous cell carcinomas) using dual-target, dual-color fluorescence in situ hybridization (FISH) assays. Chromosome 3 centromere probe was matched with a 3p14.2 probe [intron 4 of the fragile histidine triad (FHIT) gene] and a 3p21.31 probe (HSemaIV gene). We then correlated FISH results with results of molecular analyses for allelic losses at loci in the regions to which the FISH probes mapped in 20 of these cases. Although various combinations of FISH abnormalities were sometimes detected within the same specimens, individual cases could be classified according to the predominant FISH pattern, usually with one abnormality present in >60% of tumor cells. Chromosomal duplication, indicated by the presence of more than two centromeric signals, was the most frequent abnormality observed by FISH and was accompanied by loss of specific sequences on 3p in approximately one-half of the specimens in which it was observed. The most frequent abnormality observed by molecular analysis was loss of heterozygosity (LOH) in both of the chromosomal regions tested and was demonstrated in 83% of cases with chromosomal duplication. We conclude that LOH may occur in the presence of chromosomal duplication, suggesting that the duplicated chromosome is homozygous. Our findings imply that LOH occurs before chromosomal duplication during lung carcinogenesis.

Estimation of growth fraction in fine needle aspirates from non-Hodgkin's lymphoma using anti-proliferating cell nuclear antigen: correlation with the Kiel classification.

OBJECTIVE: This study was undertaken to assess whether fine needle aspirates from non-Hodgkin's lymphoma (NHL) could be used for growth fraction analysis with proliferating cell nuclear antigen (PCNA) staining and if there was a relationship between the growth fraction and cytomorphologic classification according to the Kiel classification. STUDY DESIGN: The study group consisted of 40 patients with NHL diagnosed by fine needle aspiration (FNA) cytology. The cytologic classification of the lymphomas was made by two cytopathologists on May-Grünwald-Giemsa-stained slides using the Kiel classification. There were 27 cases of low and 13 of high grade lymphoma. The estimation of the growth fraction was made by PCNA immunoreactivity. The PCNA index was quantitated in smears by counting an average of 1,000 cells, and the count was correlated with the cytomorphologic classification. RESULTS: There was a strong correlation between the PCNA index and lymphoma grading. High grade lymphomas exhibited a mean PCNA positivity of 74.0%, which was significantly higher (P < .001) than that of low grade lymphomas (17.6%). CONCLUSION: Our study showed that PCNA evaluation is suitable for smears obtained by FNA on NHL, correlates with increasing grades of lymphoma according to the Kiel classification and may offer a method of monitoring treatment of lymphoma.

AIDS-related lymphoma in Brazil. Histopathology, immunophenotype, and association with Epstein-Barr virus.

The occurrence of malignant lymphoma is an increasingly important cause of morbidity and mortality in AIDS patients. The incidence of AIDS-related lymphoma in some developing countries such as Brazil is increasing as the survival of HIV infection has improved. Although there is a clear association between several types of immunodeficiency-related lymphomas and Epstein-Barr virus (EBV), the association of EBV infection in AIDS-related lymphoma in Brazil, where the incidence of AIDS is high, is unknown. Formalin-fixed, paraffin-embedded tissue from 24 cases of AIDS-related lymphoma in Brazil were analyzed for morphologic classification, immunophenotype, and EBV association using in situ hybridization studies with an EBV-EBER1 biotinylated probe. Twenty cases of AIDS-related lymphoma were classified as non-Hodgkin's lymphoma and four cases were Hodgkin's disease. Eleven non-Hodgkin's lymphomas were classified as diffuse large cell type, five cases were small non-cleaved cell, Burkitt-type, and four cases were large cell immunoblastic non-Hodgkin's lymphoma. Eighteen cases were of B-cell phenotype; one was a T-cell lymphoma, and one was classified as null. Epstein-Barr virus (EBV) was demonstrated in the majority of tumor cells of 11 of 20 (55%) of the cases non-Hodgkin's lymphomas and in 3 of 4 (75%) cases of Hodgkin's disease. AIDS-related lymphomas in Brazil are usually of large cell/immunoblastic type, but Hodgkin's disease is also seen. Both non-Hodgkin's lymphoma and Hodgkin's disease are often associated with EBV infection. The non-Hodgkin's lymphoma is predominantly of B-cell phenotype.

PIP: While there is a clear association between several types of immunodeficiency-related lymphomas and Epstein-Barr virus (EBV), the association of EBV infection in AIDS-related lymphoma in Brazil, where the incidence of AIDS is high, has remained unknown. The authors report their findings from an analysis of tissue samples from 24 cases of AIDS-related lymphoma in Brazil. The samples were analyzed for morphologic classification, immunophenotype, and EBV association. 20 cases were classified as non-Hodgkin's lymphoma, while 4 were Hodgkin's disease. 11 non-Hodgkin's lymphomas were classified as diffuse large cell type, 5 as small, non-cleaved cell, Burkitt-type, and 4 as large cell immunoblastic non-Hodgkin's lymphoma. 18 cases were of B-cell phenotype; one was a T-cell lymphoma and one was classified as null. EBV was demonstrated in the tumor cells of 11 of the 20 non-Hodgkin's lymphoma cases and in 3 of the 4 cases of non-Hodgkin's disease.

Proliferating cell nuclear antigen (PCNA) in non-Hodgkin's lymphomas: correlation with working formulation and Kiel classification in formalin-fixed paraffin-embedded material.

PCNA is a 36-KD proliferating cell nuclear antigen associated with the cell cycle. The immunocytochemical detection of PCNA represents a useful tool for the study of tumor proliferation activity. This study documents the detection of PCNA, using antibody PC 10 in formalin-fixed, paraffin-embedded tissue, and correlates the proliferative activity of the non-Hodgkin's lymphomas (NHL) with histological grading assessed by the International Working Formulation (WF) and Kiel classification. In 92 cases of NHLs we found a strong correlation between the PCNA index and lymphoma grading. Statistically significant differences were also found between the proliferative index (PI) in low and high grade lymphomas according to the Kiel classification (t = 9.519; p < 0.001) and between low, intermediate and high grade lymphomas according to the WF classification (F = 79.01; p < 0.001). In the Kiel classification the mean of low grade lymphomas was 39.5% and of high grade 75.7%. In the WF the average of low grade lymphomas was 29.7%, intermediate 53.1% and high 75.1%. Although the differences among the groups had been significant, we found variations inside each histological subgroup in both classifications. The intermediate lymphomas were the most heterogeneous group, with PI inside the same histologic subtypes coincident with low and high grade lymphomas. Since PCNA may be used as a marker of cell proliferation in clinical studies to estimate the biological aggressiveness of lymphomas, its determination in intermediate grade NHL could be very useful to evaluate individual cases in this group and determine prognosis and probably the appropriate therapy.