Abstract Objective: This study analyzed the effect of ionizing radiation on bone microarchitecture and biomechanical properties in the bone tissue surrounding a dental implant. Methodology: Twenty rabbits received three dental morse taper junction implants: one in the left tibia and two in the right tibia. The animals were randomized into two groups: the nonirradiated group (control group) and the irradiated group, which received 30 Gy in a single dose 2 weeks after the implant procedure. Four weeks after the implant procedure, the animals were sacrificed, and the implant/bone specimens were used for each experiment. The specimens (n=10) of the right tibia were examined by microcomputed tomography to measure the cortical volume (CtV, mm3), cortical thickness (CtTh, mm) and porosity (CtPo, %). The other specimens (n=10) were examined by dynamic indentation to measure the elastic modulus (E, GPa) and Vickers hardness (VHN, N/mm2) in the bone. The specimens of the left tibia (n=10) were subjected to pull-out tests to calculate the failure load (N), displacement (mm) up to the failure point and interface stiffness (N/mm). In the irradiated group, two measurements were performed: close, at 1 mm surrounding the implant surface, and distant, at 2.5 mm from the external limit of the first measurement. Data were analyzed using one-way ANOVA, Tukey’s test and Student’s t-test (α=0.05). Results: The irradiated bone closer to the implant surface had lower elastic modulus (E), Vickers hardness (VHN), Ct.Th, and Ct.V values and a higher Ct.Po value than the bone distant to the implant (P<0.04). The irradiated bone that was distant from the implant surface had lower E, VHN, and Ct.Th values and a higher Ct.Po value than the nonirradiated bone (P<0.04). The nonirradiated bone had higher failure loads, displacements and stiffness values than the irradiated bone (P<0.02). Conclusion: Ionizing radiation in dental implants resulted in negative effects on the microarchitecture and biomechanical properties of bone tissue, mainly near the surface of the implant.

Abstract Radiation-related caries are one the most undesired reactions manifested during or after head and neck radiotherapy. Fluoride application is an important strategy to reduce demineralization and enhance remineralizaton. Objective: To evaluate the effect of the topical application of fluoride during irradiation on dental enamel demineralization. Material and Methods: Thirty molars were randomly divided into three groups: Non-irradiated (NI), Irradiated (I), Irradiated with fluoride (IF). Each group was subdivided according to the presence or absence of pH-cycling (n=5). In the irradiated groups, the teeth received 70 Gy. The enamel's chemical composition was measured using Fourier Transform Infrared Spectrometry (organic matrix/mineral ratio - M/M and relative carbonate content - RCC). Vickers microhardness (VHN) and elastic modulus (E) were evaluated at three depths (surface, middle and deep enamel). Scanning electron microscopy (SEM) was used to assess the enamel's morphology. Results: The FTIR analysis (M/M and RCC) showed significant differences for irradiation, pH-cycling and the interaction between factors (p<0.001). Without pH-cycling, IF had the lowest organic matrix/mineral ratio and relative carbonate content. With pH-cycling, the organic matrix/mineral ratio increased and the relative carbonate content decreased, except for IF. VHN was influenced only by pH-cycling (p<0.001), which generated higher VHN values. ANOVA detected significant differences in E for irradiation (p<0.001), pH-cycling (p<0.001) and for the interaction between irradiation and pH-cycling (p<0.001). Increased E was found for group I without pH-cycling. With pH-cycling, groups I and IF were similar, and showed higher values than NI. The SEM images showed no morphological changes without pH-cycling. With pH-cycling, fluoride helped to maintain the outer enamel's morphology. Conclusions: Fluoride reduced mineral loss and maintained the outer morphology of irradiated and cycled enamel. However, it was not as effective in preserving the mechanical properties of enamel. Radiotherapy altered the enamel's elastic modulus and its chemical composition.

O objetivo deste trabalho foi comparar a ingestão alimentar habitual e a freqüência de retardo do crescimento de crianças com reação intradérmica positiva para leishmaniose (Montenegro-positivas), com um grupo Montenegro-negativo. A ingestão alimentar habitual foi avaliada pelo recordatório de 24 horas e o retardo do crescimento definido segundo critérios da OMS. Crianças Montenegro-positivo (n = 9) e Montenegro-negativo (n = 17) ingeriam, respectivamente, quantidades similares de energia (1456,8 ± 314,8 vs 1316,2 ± 223,8kcal/dia) e proteínas (50,4 ± 16,7 vs 49,9 ± 13,9g/dia). Déficit de altura foi mais comum em crianças Montenegro-positivas (44,4 vs 5,9). Estes dados sugerem que a infecção prévia pela Leishmania sp afeta desfavoravelmente o estado nutricional de crianças vivendo em área endêmica.

The objective of this study was to compare growth retardation frequency, and 24-h food intake data of children with or without positive Montenegro (leishmanin) test, examined in Porteirinha town, Brazil. Daily nutrient intake was determined by 24-h food intake recall and the anthropometric data were compared to the standard values from WHO. Montenegro-positive (n = 9) and Montenegro-negative (n = 17) groups showed similar age (5.5 ± 1.9 vs 6.7 ± 2.3y), and energy (1,456.8 ± 314.8 vs 1,316.2 ± 223.8kcal) and protein (50.4 ± 16.7 vs 49.9 ± 13.9g) daily consumption, respectively. Montenegro-positive children had higher percentage of stunting than their Montenegro-negative counterparts (44.4 vs 5.9), suggesting that previous Leishmania sp infection had negative impact on children's nutritional status.

OBJETIVOS: Analisar a complexa relação entre as células mononucleares associadas ao tumor (TAMs) e as células neoplásicas, sendo resumidos sua competência imunológica, perfil da produção de citocinas e de óxido nítrico (NO) no microambiente tumoral, com aspectos atuais de como a produção desses mediadores poderia afetar o crescimento tumoral. ORIGEM DOS DADOS: Os dados foram obtidos de artigos indexados através da rede Medline durante os últimos 10 anos. As palavras-chave utilizadas na pesquisa foram basicamente: câncer, carcinoma ovariano, citocina, óxido nítrico, células mononucleares, linfócito, macrófago. SELEÇÃO DOS ESTUDOS E COLETA DOS DADOS: Foram revistos 30 trabalhos contendo dados relacionados à produção de citocinas e NO por TAMs e/ou células neoplásicas e que tentaram estabelecer uma correlação entre a produção desses mediadores e o crescimento tumoral, particularmente no carcinoma ovariano. RESUMO DOS DADOS: As TAMs consistem principalmente de macrófagos e linfócitos T que apresentam baixo índice proliferativo e baixa citotoxicidade comparada aos monócitos autólogos do sangue, embora sejam capazes de liberar várias citocinas. O perfil da expressão de citocinas poderia ajudar a explicar tanto a deficiência imunológica observada em pacientes com carcinoma em fase avançada como também o potencial das TAMs em exercer atividade antitumoral, o que torna essas células um alvo para intervenção terapêutica. Além das citocinas, o NO também é produzido no microambiente tumoral. Várias observações em animais sugerem um papel tumoricida para o NO, mas em tumores humanos seu papel não foi estabelecido podendo ser alterado durante a progressão do tumor.

AIMS: This brief review focuses on the current understanding of the complex relationship of tumor-associated mononuclear cells (TAMs) with neoplastic cells, summarizing their immunological efficiency, cytokine profile and production of nitric oxide (NO) in the tumor microenvironment, with current insights on how this might affect tumor growth. DATA SOURCE: Data was obtained through Medline from articles indexed during the last 10 years. The main key words used in the research were: cancer, ovarian cancer, cytokine, nitric oxide (NO), mononuclear cell, lymphocyte, macrophage. SELECTION OF STUDIES AND DATA COLLECTION: 30 studies were reviewed, which contained data regarding the production of cytokines and NO by TAMs or malignant cells, and tried to establish a correlation between these mediators and tumor growth, especially in ovarian carcinoma. DATA SUMMARY: TAMs consist mainly of macrophages and T lymphocytes which present lower proliferative indices and cytotoxicity compared to autologous blood monocytes, although they are able to release various cytokines. The profile of cytokine expression could help to explain both the immunological impairment observed in patients with advanced carcinoma diseases and the potential of TAMs to exert antitumor activity, which makes these cells an attractive target for therapeutic intervention. NO is also produced in the tumor microenvironment. Several reports in animals suggest a tumoricidal role for NO, but in human tumors its role has not been well-established and may change during tumor progression.