The role of epigenetic transcription repression and DNA methyltransferases in cancer

Epigenetic alterations such as DNA methylation have been implicated in the development and progression of various cancers. DNA methylation consists of the reversible addition of a methyl group to the carbon 5 position of cytosine in CpG dinucleotides and is considered essential for normal embryonic development. However, global genomic hypomethylation and aberrant hypermethylation of regulatory regions of tumor suppressor genes have been associated with chromosomal instability and transcription repression, respectively, providing neoplastic cells with a selective advantage. DNA methyltransferases are the enzymes responsible for the addition of methyl groups to CpG dinucleotides, which, together with histone modifiers, initiate the events necessary for transcription repression to occur. It has been demonstrated that increased expression of DNA methyltransferases may contribute to tumor progression through methylation-mediated gene inactivation in various human cancers. Given their importance, this article reviews the main epigenetic mechanisms for regulating transcription and its implications in cancer development.

Study of intussusceptive angiogenesis in inflammatory regional lymph nodes by scanning electron microscopy

The aim of the present study was to verify the occurrence of intussusceptive angiogenesis in blood vessels from submandibular lymph nodes responsible for lymphatic drainage of the tongue. A surgical wound inflicted on the ventral tongue of male Wistar rats and submandibular regional lymph nodes were evaluated at different postoperative periods. Scanning electron microscopy (SEM) was used to observe 123 lymph nodes at times 2, 3, 7, 10, 14, and 21 postoperative days. During the analysis of the vascular models with SEM, intussusceptive angiogenesis was observed in all groups evaluated. This was more extensive on the second and third postoperative days (83.33% and 80%, respectively), representing in these groups the expansion of the vascular chain of lymph nodes. At 21 postoperative days, intussusceptive angiogenesis (42.85%) was suggestive of vascular remodeling.

Oral Erythroplakia and Speckled Leukoplakia: retrospective analysis of 13 cases

Erythroplakia and speckled leukoplakia are oral precancerous lesions that have a high potential for malignant transformation.

Aim

A retrospective analysis was conducted to investigate the clinicopathologic features of 13 cases of oral erythroplakia and speckled leukoplakia in patients who were seen at a center specialized in stomatology and Histopathological diagnosis of oral diseases.

Materials and Methods

All cases diagnosed with erythroplakia and speckled leukoplakia between 1978 and 2006 were retrieved from the service archives.

Results

The lesions exhibited a predilection for males with a female-to-male ratio of 1:3.3. Mean age was 57 years old and soft palate was the site affected in 77% of the cases. Pain symptoms were reported by 61.5% of the patients and association with risk factors such as smoking and excessive alcohol intake was seen in 100% and in 46% of the cases, respectively. The lesions showed epithelial dysplasia, where more than 50% were diagnosed as in situ or invasive carcinoma.

Conclusions

Despite low prevalence, oral homogeneous erythroplakia and speckled leukoplakia show Histopathological alterations vary from epithelial dysplasia to invasive carcinoma. These lesions must be included among those oral lesions with the highest potential for malignant tranformation.

Angioarchitecture of the ventral surface of the tongue from Wistar rats

The goal of this study was to describe the angioarchitecture of the ventral surface of the tongue from Wistar rats using a vascular corrosion casting technique associated with scanning electron microscopy (SEM). Six Wistar rats were used for the vascular casting method with Mercox resin. Following the resin polymerization, the tongue of each animal was dissected and corroded in a 5% sodium hydroxide solution. Once the corrosion and drying of the specimens were completed, the specimens were mounted on aluminum stubs, coated with carbon and gold and analyzed under SEM. The results showed that the ventral surface of the tongue presents simple, even and abundant vasculature constituted by a vascular plexus consisting of a superficial vascular network and by the ranine veins. The superficial vascular network, made up of the ascending and descending branches, presents as a loose network, with little morphological variation between the capillary loops.

Pyogenic granuloma, peripheral giant cell granuloma and peripheral ossifying fibroma: retrospective analysis of 138 cases

AIM

The present study examined retrospectively the clinical and radiographic characteristics of pyogenic granuloma (PG), peripheral giant cell granuloma (PGCG) and peripheral ossifying fibroma (POF), located in the gingiva and alveolar ridge.

METHODS

Biopsy records of the Stomatology Service of São Lucas Hospital-PUCRS were reviewed between 1980 and 2006. The medical charts of patients with histopathologic diagnosis of PG, PGCG and POF were selected. The data obtained were evaluated by means of descriptive statistics, analysis of variance (ANOVA), and the chi-squared test (chi-squared), considering the 5% level of significance.

RESULTS

Of the 138 cases analyzed, 57.2% corresponded to PG, 22.5% to PGCG and 20.3% to POF. PG and POF exhibited a predilection for females and PGCG for males. PG occurred in younger individuals and showed a greater tendency for bleeding (P=0.018). PG showed a greater frequency of reddish color (P<0.001), PGCG purplish (P<0.001) and POF pinkish (P<0.001). In the radiographic examination, the presence of radiopaque foci was greater in POF (P<0.001), and resorption of the subjacent alveolar bone was found more often in PGCG (P<0.001). POF exhibited a longer evolution. There was no difference in lesions with respect to local irritating factors, ulceration, size, site and recurrence. Pregnancy was a factor linked to PG.

CONCLUSION

Despite the lesions investigated exhibit similar clinical characteristics, the present study demonstrated that aspects such as age of the patient and evolution, color, bleeding and radiographic characteristics can help in the differential diagnosis of these lesions.

Extensive myiasis infestation over a squamous cell carcinoma in the face. Case report

Human myiasis is a parasitosis found in tropical and underdeveloped countries. It usually affects the elderly, unhealthy and mentally disabled individuals. It is caused by dipterous that lay their eggs in necrotic or infected tissues, although areas of the body that are apparently healthy can also be affected. Frequently the fly deposits several eggs on the peripheral parts of scratches and wounds. The treatment of myiasis involves mechanical removal of the larvae with hemostatic pincers. Larvae rupture must be avoided. Application of topical ether or similar volatile substance is useful. Preventive approach measures, including basic health care, hygiene, access to primary health service, and safe water and drainage, are fundamental to prevent human myiasis. The authors present a case report of myiasis infestation over an extensive head and neck squamous cell carcinoma from a 72-year-old patient living in a rural area. Approximately 200 larvae were removed and the patient was taken to the hospital's head and neck surgery service.

Vascular corrosion casting technique steps

The vascular corrosion casting technique produces a replica of vascular beds of normal or pathological tissues. Once associated with scanning electron microscopy (SEM), this technique provides details of the three-dimensional anatomic arrangement of the vascular replica, which is the main advantage of this method. The present study is intended to describe the steps of the vascular corrosion casting technique and the different ways to perform them. them.

Highly aggressive brown tumor in the jaw associated with tertiary hyperparathyroidism

The purpose of this paper is to describe the case of a 12-year-old patient with end-stage chronic renal failure. The patient presented with an osteolytic lesion in the mandible with expansion of the buccal, lingual, and occlusal cortical bone, as well as dislocation of the teeth in the area. The calcium, creatinine, and parathormone (PTH) contents of the blood were elevated. A histopathological examination of the jaw lesion revealed the presence of a brown tumor lesion, which is associated with hyperparathyroidism (HPT). An adenoma was found in the upper left parathyroid, a finding compatible with the diagnosis of tertiary HPT. In spite of the continuous ambulatory peritoneal dialysis instituted, the osteolytic lesion kept on growing. A conservative treatment employing an association of intralesional corticosteroid and salmon calcitonin (inhaled) was carried out. After 14 months of therapy, a reduction in size and complete calcification of the lesion were achieved. Aesthetic osteoplasty of the jaw was then performed.

Histologic evaluation of effect of thiocyanate topical application on hamster cheek pouch

The present study was conducted to investigate the effect of topical thiocyanate (SCN(-)) application on hamster cheek pouch mucosa. Sixty-six hamsters were divided into two groups. The test substance containing potassium thiocyanate was applied on the hamsters' cheek pouches at 55 mg/kg dosages. Cheek pouches were grossly examined after 12 weeks. Histometric evaluation included height measurements from the epithelium without stratum corneum, stratum corneum, and full epithelium. Clear cells frequency was compared between groups. Results were analyzed using Student's t test. The experimental group showed a lower height of the stratum corneum (p=0.035) and higher frequency of clear cells (p<0.001). There was no height difference for the epithelium without stratum corneum (p=0.677) and full epithelium (p=0.904) between groups. SCN(-) promotes no gross alterations on hamsters' cheek pouch and does not induce dysplastic features at the epithelium or inflammation at the connective tissue. The ion promotes histologic alterations on mucosa that need to be investigated in further studies.

Bisfosfonatos e osteonecrose maxilar: revisão da literatura e relato de dois casos

Os bisfosfonatos são medicamentos amplamente administrados a pacientes portadores de metástases tumorais em tecido ósseo e a pacientes com osteoporose. A droga reduz a reabsorção óssea, estimula a atividade osteoblástica, assim como inibe o recrutamento e promove a apoptose de osteoclastos. A associação entre o uso dos bisfosfonatos e uma forma peculiar de osteonecrose dos maxilares tem sido relatada, principalmente, em pacientes submetidos a exodontias. No presente estudo, são apresentados dois casos de pacientes em uso de bisfosfonatos para tratamento de metástases ósseas, que desenvolveram osteonecrose maxilar. Na literatura, não há relatos de um tratamento eficaz para a enfermidade, porém o uso de antibióticos por um longo período parece apresentar os melhores resultados. Ainda, a possibilidade de substituição do medicamento deve ser considerada dentro de uma equipe multidisciplinar. Tendo em vista a dificuldade de tratamento e o risco representado pelas intervenções cirúrgicas dos maxilares, pacientes que serão submetidos ao uso de bisfosfonatos devem passar por um criterioso exame odontológico, e todos os procedimentos cirúrgicos necessários devem ser realizados previamente ao início da terapia com o medicamento.

Squamous cell carcinoma of the tongue after bone marrow transplantation in a patient with Fanconi anemia

Fanconi anemia (FA) is an autosomal recessive disorder that might cause a variety of congenital and developmental abnormalities. The most important features of FA are progressive bone marrow failure and development of malignancies, particularly acute myeloid leukemia and solid tumors. This paper reports the case of a 12-year-old patient with FA assisted at the Stomatology and Bucomaxillofacial Cancer Prevention Service of São Lucas Hospital, Brazil, who had been submitted to bone marrow transplantation (BMT) at the age of 5 and exhibited oral lesions characteristic of chronic graft versus host disease (GVHD). The patient was treated and followed-up for the oral lesions. Eleven years after the BMT, he developed squamous cell carcinoma of the tongue with an aggressive behavior, which was considered an untreatable condition. The patient died few months later from asphyxia at the age of 16. The reasons for development of these malignant conditions are unknown. However, chromosomal instability typically observed in FA cases, BMT factors and GVHD have been considered. Systematic follow-up of these patients allows early and less invasive therapeutic approaches.

Association between recurrent aphthous stomatitis and salivary thiocyanate levels

The aim of this work was to investigate the association between recurrent aphthous stomatitis (RAS) and salivary thiocyanate levels. The sample comprised men and women of age ranging from 15 to 55 years, who were allocated to four groups: 28 patients in RAS active phase (group 1); 28 patients in RAS remission phase (group 2); 29 smokers (group 3); 26 non-smokers without RAS (group 4). Samples of whole saliva mechanically stimulated were collected, and thiocyanate levels were measured. The results were analyzed by ANOVA and paired t-test. Mean salivary thiocyanate values were 0.55 mM, 0.64 mM, 2.36 mM and 0.96 mM in groups 1 (active RAS), 2 (remission RAS), 3 (smokers) and 4 (control), respectively. There was no significant difference in thiocyanate levels when groups 1 and 2 were compared with group 4. Group 3 showed a significantly higher thiocyanate concentration when compared with groups 1, 2 and 4 (P < 0.05). There was no significant difference in thiocyanate levels between groups 1 and 2 (P > 0.05). It is therefore suggested that there is no association between RAS and salivary thiocyanate levels.

Análise microscópica do efeito da radioterapia fracionada em glândula submandibular de rato

OBJETIVO: O estudo teve por objetivo avaliar, quantitativamente, as alterações histológicas induzidas pela radioterapia sobre o parênquima e o estroma da glândula submandibular. MATERIAIS E MÉTODOS: A amostra foi constituída por 30 ratos Wistar, distribuídos em dois grupos: teste e controle. Os 15 animais do grupo-teste foram submetidos a radioterapia da região de cabeça e pescoço, na modalidade fracionada rotacional por cobalto-60, na dose de 60 Gy, realizada em frações de 2 Gy diários, por seis semanas. Decorridas 60 horas da conclusão da radioterapia, as glândulas submandibulares dos animais de ambos os grupos foram excisadas, processadas pela técnica da parafina, coradas com hematoxilina e eosina e analisadas à microscopia óptica. O volume proporcional médio correspondente ao parênquima e ao estroma glandulares foi obtido pelo método estereológico de contagem manual de pontos. RESULTADOS: O volume proporcional de ácinos no grupo irradiado (60,67% ± 6,43) foi significativamente menor que no grupo-controle (67,42% ± 10,90) (p = 0,048), entretanto, não houve diferença estatisticamente significativa entre os grupos para as variáveis parênquima, ductos e estroma (teste t de Student, p > 0,05). CONCLUSÃO: O esquema radioterápico empregado provocou atrofia acinar da glândula submandibular, sem, no entanto, ocorrer alteração quantitativa total do estroma ou do parênquima.

Viral coinfection in the oral cavity of HIV-infected children: relation among HIV viral load, CD4+T lymphocyte count and detection of EBV, CMV and HSV

Viral coinfection in the oral cavity associated to HIV infection was evaluated in 180 children from birth to 13 years of age of both sexes. The oral examinations were performed at the Pediatric AIDS Outpatient Clinic, São Lucas Hospital and Clinic Hospital, both in Porto Alegre, Brazil and at the School of Dental Medicine, University Hospital Center, State University of New York at Stony Brook, USA. The aim of this study was to identify the presence of viral infections in the oral cavity. PCR technique was used to determine opportunistic viral infections caused by CMV, EBV, and HSV in mucosal swabs. A high frequency of viral infection was detected in the oral cavity of HIV-infected children determined by the PCR technique. HIV-infected children with viruses had a favorable CD4+T lymphocyte count and unfavorable viral load.

[Clinical-epidemiologic profile of paracoccidioidomycosis at the Stomatology Department of São Lucas Hospital, Pontificia Universidade Católica of Rio Grande do Sul]

The aim of the article was to describe clinical and epidemiological features of 61 oral paracoccidioidomycosis cases from the Stomatology Department of São Lucas Hospital, analyzed from July 1976 to June 2004. The State of Rio Grande do Sul is an endemic region due to ecoepidemiologic conditions, that are favorable for the development of the yeast. Men are the most affected gender, with 58 (95%) affected compared to 3 (5%) women. Ii is most prevalent (70.5%) between 40 and 59 years of age. Agricultural labor was the most common occupation with 27/61 (44.3%) patients. Tobacco smoking was prevalent in 52 (85.3%) of the sample, and alcoholism was a frequent finding. All the patients showed stomatologic manifestations, with ulcers and mulberry-like stomatitis the most prevalent, these oral lesions were also observed in many anatomical sites. Alterations were present in 32 (65.3%) of the pulmonary radiographs.

Comparative analyses between the smoking habit frequency and the nucleolar organizer region associated proteins in exfoliative cytology of smokers' normal buccal mucosa

An evaluation of the cellular alterations in the smoker's oral mucosal cells was performed. Exfoliative Citology technique were applied and the cytologic smears stained with silver for quantitative analyses of Argyrophilic nucleolar organizer regions. (AgNORs). Cytologic smears were collected from two anatomic sites, mouth floor and tongue border with the purpose of relating the frequency of smoking with the quantitative analyses of the AgNORs. This study showed that the average number of AgNORs/nucleus is related with the number of cigarettes per day in the mouth floor of smoker's. These results suggest a possible relation between the number of cigarettes per day and an increase rate of cellular proliferation in the oral mucosal cells.

Carcinoma Verrucoso e Leucoplasia em um mesmo paciente: relato de caso clínico

Os autores descrevem o caso clínico de duas lesões presentes há mais de 4 anos, em uma paciente do sexo feminino, 65 anos de idade, que negou hábitos de tabagismo e etilismo. Uma das lesões encontrava-se em mucosa jugal, lado direito, exofítica, com superfície verrucóide e esbranquiçada; outra localizava-se na borda da língua, lado direito, em forma de placa branca. Os diagnósticos clínicos estabelecidos foram de Carcinoma Verrucoso para a lesão de mucosa jugal e de Leucoplasia para a lesão de língua, os quais foram confirmados no exame histopatológico. A paciente foi encaminhada para remoção cirúrgica de ambas as lesões. Decorridos 6 meses da cirurgia, a mesma encontra-se em bom estado de saúde geral, recuperando os movimentos faciais e linguais, através de fisioterapia.

[Oral manifestations, CD4+ T-lymphocytes count and viral load in Brazilian and North-American HIV-infected children]

Oral manifestations related to HIV infection were evaluated in 184 children of both genders, aging 0-13 years. The oral exams were carried out at the Ambulatory of Pediatric AIDS, São Lucas Hospital and at the Clinics Hospital, both in Porto Alegre, RS, Brazil, and at the University Hospital and School of Dentistry, State University of New York, Stony Brook, NY, USA, from January 1999 to May 2000. A high prevalence of oral manifestations was observed both in Brazilian (72.73%) and American (53.66%) children. The most frequent manifestations were cervical lymphadenopathy, swelling of the parotids, erythematous candidiasis, petechia, gingivitis, xerostomia and angular cheilitis. Children with oral manifestations had almost normal counts of CD4+ T lymphocytes and high viral load.

Evaluation of the nucleolar organizer region associated proteins in exfoliative cytology of normal buccal mucosa. Effect of smoking

An evaluation of cellular alterations in the smoker's oral mucosal cells was performed. The Exfoliative Cytology technique was applied and the cytological smears stained with silver for the enumeration of Argyrophilic nucleolar organizer regions (AgNORs). Cytological smears were collected from two anatomic sites: floor of the mouth and tongue border, in both groups, smokers and non smokers, with a purpose of correlating the smoking habit to possible cellular alterations. The enumeration of the AgNORs showed that the average number of AgNORs is higher in smokers. There is a significant difference (P=0.0001) between smears from the floor of the mouth and from tongue border in the smoking group. In this study, no correlation between number of cigarettes, age and gender was found, but the results suggest that there might be a correlation between the smoking habit and an increased rate of cellular proliferation in the oral mucosal cells.