Comprometimento da pálpebra e via lacrimal excretora em portador de leishmaniose cutâneo-mucosa: relato de caso

Objetivo: Apresentar um portador de leishmaniose com lesão palpebral e dilatação de via lacrimal excretora. Relato de caso: O paciente em questão foi portador de leishmaniose do tipo cutâneo-mucosa, tendo apresentado múltiplas lesões de pele, ectrópio da pálpebra inferior, lesões na mucosa nasal e alterações na drenagem lacrimal. Discussão: O acometimento da pálpebra e da via lacrimal raramente ocorre em portadores de leishmaniose. Os autores chamam atenção para o diagnóstico e para a necessidade de se adotar medidas preventivas contra os vetores e a rápida instituição do tratamento.

Histological and immunohistochemical study of the expression of p53 and ki-67 proteins in the mucosa of the tongue, pharynx and larynx of rats exposed to cigarette smoke

Introduction: Head and neck cancers are linked to smoking. The most affected sites are the oral cavity, pharynx and larynx. Experimental studies show epithelial lesions caused by cigarette smoke. Objectives: To investigate in rats the effects of acute cigarette smoke exposure on the mucosa of the tongue, pharynx and larynx.Material and method: Wistar rats were allocated into two groups of 20 animals: CG (control) receiving food and water ad libitum and TG (Tobacco) exposed to the smoke of 40 cigarettes/day for 60 days. Biopsy of their tongues, pharynxes and larynxes were subjected to histopathological, histomorphometric and immunohistochemical studies of protein p53 and ki-67.Result: The histological analysis of tongue from the Tobacco group revealed epithelial hyperplasia (90%), basal cell hyperplasia (95%) and mild to moderate dysplasia (85%). In pharynx showed basal cell hyperplasia (85%), dysplasia (25%) and vascular congestion (95%). In larynx showed basal cell hyperplasia (70%), epithelial hyperplasia (55%), congestion (100%) and inflammatory infiltrate (25%). Morphometric analysis revealed that keratin layer thickness was greater in the tobacco group. P53 immunoexpression was negative in both groups. Ki-67 immunoexpression was positive in basal cell nuclei but in parabasal cell nuclei it was positive only in the Tobacco group.Conclusions: The exposure of animals to cigarette smoke for 60 days resulted in benign lesions. The duration of exposure was not enough to cause the development cancer, as confirmed by the negative expression of p53 protein in all slides examined. Analysis of ki-67 expression showed intense epithelial proliferation in response to damage.

Consequences of Chronic Nasal Obstruction on the Laryngeal Mucosa and Voice Quality of 4- to 12-Year-Old Children

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

Effects of uracil calculi on cell growth and apoptosis in the BBN-initiated Wistar rat urinary bladder mucosa

The different potential of initiated and non-initiated urinary bladder mucosa (UBM) to develop neoplasia was quantitatively evaluated in the male Wistar rat. Initiation of carcinogenesis was accomplished with N-butyl-N- (4-hydroxybutyl) -nitrosamine (BBN). Stimuli for cell proliferation and apoptosis were obtained by exposure followed by withdrawal of 3% Uracil in the diet. The proliferation index (PI) was estimated in UBM immunostained for the proliferating nuclear cell antigen (PCNA). The apoptotic index (AI) and the density of papillary/nodular hyperplasia (PNH) were estimated in hematoxilin-eosin stained sections. PNH was the main proliferative response to the mechanical irritation by uracil, irrespective of previous initiation with BBN. Uracil exposure induced higher PI and PNH density in the initiated rats. After uracil withdrawal, there was a significant increase of the AI in both uracil-treated groups, which correlated well to the respective PNH density. However, at the end of the experiment, PNH incidence and density were significantly higher in the BBN-initiated mucosa, which also presented 18% incidence of papillomas and 27% of carcinomas. Therefore, under prolonged uracil calculi trauma, the UBM of BBN-initiated Wistar rats gives rise to epithelial proliferative lesions that progress to neoplasia through acquired resistance to apoptosis. (C) 1999 Wiley-Liss, Inc.

Viable human buccal mucosa cells do not yield typical nucleoids: Impacts on the single-cell gel electrophoresis/comet assay

Buccal mucosa (BM) cells have been used in human biomonitoring studies for detecting DNA adducts and chromosomal damage in an epithelial cell population. In the present study, we have investigated if human BM cells are suitable for use in the single-cell gel electrophoresis (SCGE)/Comet assay as an approach for estimating the exposure of epithelial cells to DNA-damaging agents. Our results indicate that only a few cells from BM cell samples yield comets that can be analyzed by current methods, and that the yield of cells with comets is independent of the percentage of viable BM cells in the sample. Data generated after enzymatic enrichment of viable cells and immunomagnetic separation of epithelial cells suggest that most of the BM cells that do form comets are probably leukocytes. Moreover, by reevaluating specific cells after running the Comet assay, we found that viable epithelial BM cells give rise to atypical comets that are not included in the analysis. Comparing DNA migration patterns between small groups of smokers and nonsmokers indicated that long-term smoking had no effect on the subpopulation of cells that yield typical comets. Our results indicate that the SCGE assay, as it is commonly performed, may not be useful for genotoxicity monitoring in human epithelial BM cells.

DNA damage and aberrant crypt foci as putative biomarkers to evaluate the chemopreventive effect of annatto (Bixa orellana L.) in rat colon carcinogenesis

Chemoprevention opens new perspectives in the prevention of cancer and other degenerative diseases. Use of target-organ biological models at the histological and genetic levels can markedly facilitate the identification of such potential chemopreventive agents. Colon cancer is one of the highest incidence rates throughout the world and some evidences have indicated carotenoids as possible agents that decrease the risk of colorectal cancer. In the present study, we evaluate the activity of annatto (Bixa orellaria L.), a natural food colorant rich in carotenoid, on the formation of aberrant crypt foci (ACF) induced by dimethy1hydrazine (DMH) in rat colon. Further, we investigate, the effect of annatto on DMH-induced DNA damage, by the comet assay. Male Wistar rats were given s.c. injections of DMH (40 mg/kg body wt.) twice a week for 2 weeks to induce ACE They also received experimental diets containing annatto at 20, 200 or 1000 ppm for five 5 weeks before (pre-treatment), or 10 weeks after (post-treatment) DMH treatment. In both protocols the rats were sacrificed on week 15th. For the comet assay, the animals were fed with the same experimental diets for 2 weeks. Four hours before the sacrifice, the animals received an s.c. injection of DMH (40 mg/kg body wt.). Under such conditions, dietary administration of 1000 ppm annatto neither induce DNA damage in blood and colon cells nor aberrant crypt foci in rat distal colon. Conversely, annatto was successful in inhibiting the number of crypts/colon (animal), but not in the incidence of DMH-induced ACF, mainly when administered after DMH. However, no antigenotoxic effect was observed in colon cells. These findings suggest possible chemopreventive effects of annatto through their modulation of the cryptal cell proliferation but not at the initiation stage of colon carcinogenesis. (c) 2005 Elsevier B.V. All rights reserved.

Protective action of propolis on the rat colon carcinogenesis

Propolis is a honeybee product with several biological and therapeutical properties. Its effect on the process of colon carcinogenesis and DNA damage were evaluated in the male Wistar rats using the aberrant crypt foci (ACF) assay and the comet assay, respectively. For both tests, animals were treated with the colon carcinogen 1,2 dimethylhydrazine (DMH, 40 mg/kg, s.c.) for 2 weeks (two injections/week) in order to induce both DNA damage and ACF. The animals were divided into groups that received propolis (ethanolic extract) at three different doses (10, 30, and 90 mg/kg b.w., by gavage), either simultaneously or after DMH treatment. For the comet assay, peripheral blood samples were collected 4 h after the last DMH treatment. All animals were sacrificed at the 5th week for evaluation of ACF. The results show that only the intermediate dose (30 mg/kg) of propolis, administered after DMH initiation, is significantly associated to a smaller number of aberrant crypts in the distal colon. No effect on DNA damage in peripheral blood cells, however, was verified by the comet assay. These data suggest that propolis has a protective influence on the process of colon carcinogenesis, suppressing the development of preneoplastic lesions, and probably exerts no protection against the initiation of carcinogenesis.

Cytogenetic damage in circulating lymphocytes and buccal mucosa cells of head-and-neck cancer patients undergoing radiotherapy

This study evaluated cytogenetic damage by measuring the frequency of micronucleated cells (MNC) in peripheral blood and buccal mucosa of head-and-neck cancer patients undergoing radiotherapy.MNC frequencies were assessed in 31 patients before, during, and after radiotherapy, and in 17 C, healthy controls matched for gender, age, and smoking habits. Results showed no statistically significant difference between patients and controls prior to radiotherapy in cytokinesis-blocked lymphocytes or buccal mucosa cells. During treatment, increased MNC frequencies were observed in both cell types. Micronucleated lymphocyte levels remained high in samples collected 30 to 140 days after the end of treatment, while MNC frequency in buccal mucosa decreased to values statistically similar to baseline values. There is controversy over the effects of age, smoking habit, tumor stage, and/or metastasis on MNC frequency. However, increased frequency of micronucleated buccal mucosa cells was seen in patients under 60 years old and in those with tumors >4cm.In conclusion, the data show that radiotherapy has a potent clastogenic effect in Circulating lymphocytes and buccal mucosa cells of head-and-neck cancer patients, and that the baseline MNC frequency in these two tissues is not a sensitive marker for head-and neck neoplasm.

Genomic instability in non-neoplastic oral mucosa cells can predict risk during 4-nitroquinoline 1-oxide-induced rat tongue carcinogenesis

4-Nitroquinotine 1-oxide (4NQO)-induced rat tongue carcinogenesis is a useful model for studying oral squamous cell carcinoma. The aim of this study was to investigate the level of DNA damage induced by 4NQO in oral mucosa cells by the single cell get (comet) assay. Mate Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO solution by drinking water for 4, 12 or 20 weeks. Ten animals were used as negative control. Statistically significant increase of DNA damage was observed in non-neoplastic oral cells at four weeks of 4NQO administration when compared with control (P < 0.05). The level of DNA damage was directly associated with the severity of histological changes. The results suggest that histologically normal tissue is able to harbor genetically unstable cells contributing to the initiation of oral carcinogenesis. Genomic instability appears to be associated with the risk and progression of oral cancer. (C) 2004 Elsevier Ltd. All rights reserved.

Cigarette smoke affects apoptosis in rat tongue mucosa: Role of bcl-2 gene family

While it has been clearly demonstrated that smoking is the most significant exogenous factor involved in oral carcinogenesis, little is known about the global molecular and cellular changes that occur prior to the appearance of clinically detectable symptoms. Thus, the aim of this study was to investigate the expressivity of bcl-2, bax and PCNA in the rat tongue mucosa exposed to cigarette smoke by means of immunohistochemistry. A total of twelve male Wistar rats were distributed into 2 groups: negative control and experimental group exposed to cigarette smoke during 75 days. After experimental period, no histopathological changes in the tongue mucosa were detected in the negative control and the experimental group. on the other hand, an overexpression of bcl-2 was detected (p < 0.01) throughout all layers of the epithelium, whereas bax did not show significant differences (p > 0.05). Also, the labeling index for bcl-2 and bax showed an increase 75 days after cigarette exposure (p < 0.01). PCNA-labeling index did not show remarkable changes between groups. Taken together, our results show that bcl-2 is overexpressed in the rat tongue keratinocytes after cigarette smoke exposure.

Aberrant crypt foci and colon cancer: comparison between a short- and medium-term bioassay for colon carcinogenesis using dimethylhydrazine in Wistar rats

Aberrant crypt foci (ACF) in the colon of carcinogen-treated rodents are considered to be the earliest hallmark of colon carcinogenesis. In the present study the relationship between a short-term (4 weeks) and medium-term (30 weeks) assay was assessed in a model of colon carcinogenesis induced by dimethylhydrazine (DMH) in the rat. Six-week-old male Wistar rats were given subcutaneous injections of DMH (40 mg/kg) twice a week for 2 weeks and killed at the end of the 4th or 30th week. ACF were scored for number, distribution pattern along the colon and crypt multiplicity in 0.1% methylene-blue whole-mount preparations. ACF were distinguished from normal crypts by their larger size and elliptical shape. The incidence, distribution and morphology of colon tumors were recorded. The majority of ACF were present in the middle and distal colon of DMH-treated rats and their number increased with time. By the 4th week, 91.5% ACF were composed of one or two crypts and 8.5% had three or more crypts, while by the 30th week 46.9% ACF had three or more crypts. Thus, a progression of ACF consisting of multiple crypts was observed from the 4th to the 30th week. Nine well-differentiated adenocarcinomas were found in 10 rats by the 30th week. Seven tumors were located in the distal colon and two in the middle colon. No tumor was found in the proximal colon. The present data indicate that induction of ACF by DMH in the short-term (4 weeks) assay was correlated with development of well-differentiated adenocarcinomas in the medium-term (30 weeks) assay.

High prevalence of aggregative adherent Escherichia coli strains in the mucosa-associated microbiota of patients with inflammatory bowel diseases

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

Lack of chemoprevention of dietary Agaricus blazei against rat colonic aberrant crypt foci

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of lycopene, synbiotic and their association on early biomarkers of rat colon carcinogenesis

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