Chromosome damage induced by 5-azacytidine under the influence of caffeine or cytosine arabinoside in CHO-K1 (wild-type) and XRS-5 (mutant) cell lines

5-azacytidine (5-azaC) treatment combined with cytosine arabinoside (ara-C) or caffeine were performed in vitro in Chinese hamster cells, CHO-K1 (wild-type) and xrs-5 (mutant) cell lines, in order to compare the cell response to the induction of chromosomal aberrations. Exponentially growing cells were treated with 5-azaC (4-16 uM) for 1 h, the cells were washed and incubated for 7 h, and 500 uM caffeine or 5 uM ara-C were added to the cultures for the last 2 h. In both cell lines, 5-azaC induced a significantly increase (P<0.01) in the frequencies of aberrations; in the combined treatments (5-azaC + Ara-C), a significant reduction (P<0.05) was observed for the aberrations which were randomly distributed. Caffeine had no influence at the same conditions. 5-azaC induced-DNA lesions were probably processed at S/G2 phase in a common pathway in both cell lines, but alternatively, 5-azaC may cause xrs-5 cells to revert to the wild-type.

Fluoride does not induce DNA breakage in Chinese hamster ovary cells in vitro.

Fluoride has been widely used in dentistry because it is a specific and effective caries prophylactic agent. However, excess fluoride may represent a hazard to human health, especially by causing injury to genetic material. Genotoxicity tests represent an important part of cancer research to assess the risk of potential carcinogens. In the current study, the potential DNA damage associated with exposure to fluoride was assessed by the single cell gel (comet) assay in vitro. Chinese hamster ovary cells were exposed to sodium fluoride (NaF) at final concentration ranging from 7 to 100 micro/ml for 3 h, at 37 dgrees C. The results pointed out that NaF in all concentrations tested did not contribute to DNA damage as depicted by the mean tail moment and tail intensity. These findings are clinically important since they represent an important contribution to a correct evaluation of the potential health risk associated with the exposure to dental agents.

Tamoxifen down-regulates CaMKII messenger RNA levels in normal human breast tissue

Tamoxifen was proven to reduce the incidence of breast cancer by 49% in women at increased risk of the disease in the Breast Cancer Prevention Trial. In order to identify potential candidates to explain the preventive effect induced by tamoxifen on breast cancer, normal breast tissue obtained from 42 fibroadenoma patients, randomly assigned to receive placebo or tamoxifen, was analyzed by the reverse Northern blot and RT-PCR techniques. The cDNA fragments used on Northern blot membranes were generated by the Human Cancer Genome Project funded by the Ludwig Institute for Cancer Research and FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo, Brazil). Total RNA was obtained from normal breast tissue from patients with clinical, cytological and ultrasound diagnosis of fibroadenoma. After a 50-day treatment with tamoxifen (10 or 20 mg/day) or placebo, normal breast tissue adjacent to the tumor was collected during lumpectomy with local anesthesia. One differentially expressed gene, Calcium/calmodulin-dependent protein kinase II (CaMKII), was found to be down-regulated during TAM treatment. CaMKII is an ubiquitous serine/threonine protein kinase that has been implicated in the diverse effects of hormones utilizing Ca2+ as a second messenger as well as in c-fos activation. These results indicate that the down-regulation of CaMKII induced by TAM might represent alternative or additional mechanisms of the action of this drug on cell cycle control and response to hormones in normal human breast tissue.

Testes de biocompatibilidade in vitro de duas formas comerciais do agregado de trióxido mineral

Recently, regular and white mineral trioxide aggregate (MTA) are being used in Dentistry as retrofilling materials. Genotoxicity and cytotoxicity tests form an important part of cancer research and risk assessment of potential carcinogens. Thus, the goal of this study was to examine the genotoxicity and cytotoxicity of regular and white MTA in vitro by the single cell gel (comet) assay and trypan blue exclusion test, respectively. Mouse lymphoma cells were exposed to two presentation forms of MTA at final concentrations ranging from 1 to 1,000 μg/mL for 3 h at 37°C. The results showed that both compounds tested did not produce genotoxic effects at all concentrations evaluated. Likewise, no statistically significant differences (p > 0.05) were observed in cytotoxicity. Taken together, our results suggest that regular and white MTA are not genotoxins and are not able to interfere in cellular viability as assessed by single cell gel (comet) assay and trypan blue assay, respectively.

Lack of DNA damage induced by fluoride on mouse lymphoma and human fibroblast cells by single cell gel (comet) assay

Fluoride has widely been used in Dentistry because it is a specific and effective caries prophylactic agent. However, excess fluoride may represent a hazard to human health, especially by causing injury on genetic apparatus. Genotoxicity tests constitute an important part of cancer research for risk assessment of potential carcinogens. In this study, the potential DNA damage associated with exposure to fluoride was assessed by the single cell gel (comet) assay in vitro. Mouse lymphoma and human fibroblast cells were exposed to sodium fluoride (NaF) at final concentration ranging from 7 to 100 μg/mL for 3 h at 37μC. The results pointed out that NaF in all tested concentrations did not contribute to DNA damage as depicted by the mean tail moment and tail intensity for both cellular types assessed. These findings are clinically important because they represent a valuable contribution for evaluation of the potential health risk associated with exposure to agents usually used in dental practice.

Medium-term tongue carcinogenesis assays: A comparative study between 4-nitroquinoline 1-oxide (4NQO)-induced rat and dimethylbenzanthracene (DMBA)-induced hamster carcinogenesis

The most used animal models in oral cancer research are the hamster treated by dimethylbenzanthracene (DMBA), and the rat treated by 4-nitroquinoline 1-oxide (4NQO). The purpose of this study was to compare the DMBA-induced hamster tongue carcinogenesis and 4NQO-induced rat tongue carcinogenesis by means of morphological analysis. Male Wistar rats were distributed into three groups of ten animals each and treated with 50 ppm 4NQO solution by drinking water for 4, 12 or 20 weeks. A total of 18 Syrian golden hamsters were submitted to 0.5% DMBA (dissolved in acetone) topical application three times/week for 4, 12 and 20 weeks. The primary histopathological change i.e., hyperplasia and hyperkeratosis, was evidenced after 4 weeks treatment with DMBA. Regarding 12 weeks treatment, 4NQO and DMBA were able to induce morphological changes as depicted by hyperplasia and dysplasia. At 20 weeks, squamous cell carcinoma was found in the majority of animals for both carcinogens used. Taken together, our results suggest that the hamster experimental model disclosed aspects related with tongue carcinogenesis in lesser time than rats. Probably, such discrepancies depend strongly on route of administration and the susceptibility with respect to animal species. © 2006 Elsevier GmbH. All rights reserved.

Baseline and stress-induced plasma corticosterone concentrations of mice selectively bred for high voluntary wheel running

The hypothalamic-pituitary-adrenal (HPA) axis is important in regulating energy metabolism and in mediating responses to stressors, including increasing energy availability during physical exercise. In addition, glucocorticoids act directly on the central nervous system and influence behavior, including locomotor activity. To explore potential changes in the HPA axis as animals evolve higher voluntary activity levels, we characterized plasma corticosterone (CORT) concentrations and adrenal mass in four replicate lines of house mice that had been selectively bred for high voluntary wheel running (HR lines) for 34 generations and in four nonselected control (C) lines. We determined CORT concentrations under baseline conditions and immediately after exposure to a novel stressor (40 min of physical restraint) in mice that were housed without access to wheels. Resting daytime CORT concentrations were approximately twice as high in HR as in C mice for both sexes. Physical restraint increased CORT to similar concentrations in HR and C mice; consequently, the proportional response to restraint was smaller in HR than in C animals. Adrenal mass did not significantly differ between HR and C mice. Females had significantly higher baseline and postrestraint CORT concentrations and significantly larger adrenal glands than males in both HR and C lines. Replicate lines showed significant variation in body mass, length, baseline CORT concentrations, and postrestraint CORT concentrations in one or both sexes. Among lines, both body mass and length were significantly negatively correlated with baseline CORT concentrations, suggesting that CORT suppresses growth. Our results suggest that selection for increased locomotor activity has caused correlated changes in the HPA axis, resulting in higher baseline CORT concentrations and, possibly, reduced stress responsiveness and a lower growth rate. © 2007 by The University of Chicago. All rights reserved.

Anatomical features of the urethra and urinary bladder catheterization in female mice and rats. An essential translational tool

PURPOSE: To present fundamental anatomical aspects and technical skills necessary to urethra and urinary bladder catheterization in female mice and rats. METHODS: Urethral and bladder catheterization has been widely utilized for carcinogenesis and cancer research and still remains very useful in several applications: from toxicological purposes as well as inflammatory and infectious conditions to functional aspects as bladder dynamics and vesicoureteral reflux, among many others. RESULTS: Animal models are in the center of translational research and those involving rodents are the most important nowadays due to several advantages including human reproducibility, easy handling and low cost. CONCLUSIONS: Although technical and anatomical pearls for rodent urethral and bladder access are presented as tackles to the advancement of lower urinary tract preclinical investigation in a broaden sight, restriction to female animals hampers the male microenvironment, demanding future advances.

Expressão do gene FOXE1 em culturas de osteossarcoma canino

Pós-graduação em Medicina Veterinária - FMVZ

Associação entre fatores epidemiológicos e neoplasias mamárias em cadelas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Prevalence of human T cell leukemia virus-I (HTLV-I) antibody among populations living in the Amazon region of Brazil (preliminary report)

Prevalence of human T cell leukemia virus-I (HTLV-I) antibody among populations living in the Amazon region of Brazil (preliminary report)NakauchiC. M.LinharesA. C.MaruyamaK.KanzakiL. I.MacedoJ. E.AzevedoV. N.CassebJ. S. R. Fundação Serviços de Saúde Pública, Seção de Vírus, Instituto Evandro Chagas Belém Brasil Chiba Cancer Research Institute, Department of Pathology Chiba Japan Universidade Federal do Pará Belém Brasil Instituto Offir Loyola Belém Brasil Faculdade Estadual de Medicina Belém Brasil 0319908512933Forty-tree (31.4%) out of 137 serum samples obtained from two Indian communities living in the Amazon region were found to be positive for HTLV-I antibody, as tested by enzyme-linked immunosorbent assay (Elisa). Eighty-two sera were collected from Mekranoiti Indians, yielding 39% of positivity, whereas 11 (20.0%) or the 55 Tiriyo serum samples had antibody to HTLV-I. In addition, positive results occurred in 10 (23.2%) out of 43 sera obtained from patients living in the Belem area, who were suffering from cancer affecting different organs. Five (16.7%) out of 30 Elisa positive specimens were also shown to be positive by either Western blot analysis (WB) or indirect immunogold electron microscopy (IIG-EM).

Glutathione-s-transferase modified electrodes for detecting anticancer drugs

With the fast growth of cancer research, new analytical methods are needed to measure anticancer drugs. This is usually accomplished by using sophisticated analytical instruments. Biosensors are attractive candidates for measuring anticancer drugs, but currently few biosensors can achieve this goal. In particular, it is challenging to have a general method to monitor various types of anticancer drugs with different structures. In this work, a biosensor was developed to detect anticancer drugs by modifying carbon paste electrodes with glutathione-s-transferase (GST) enzymes. GST is widely studied in the metabolism of xenobiotics and is a major contributing factor in resistance to anticancer drugs. The measurement of anticancer drugs is based on competition between 1-chloro-2,4-dinitrobenzene (CDNB) and the drugs for the GST enzyme in the electrochemical potential at 0.1 V vs. Ag/AgCl by square wave voltammetry (SWV) or using a colorimetric method. The sensor shows a detection limit of 8.8 mu M cisplatin and exhibits relatively long life time in daily measurements. (C) 2014 Elsevier B.V. All rights reserved.

Short interspersed CAN SINE elements as prognostic markers in canine mammary neoplasia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genomic profiling of human penile carcinoma predicts worse prognosis and survival

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)