New Amino Naphthoquinone Derivatives as Anti-Trypanosoma cruzi Agents Targeting Trypanothione Reductase.

To develop novel chemotherapeutic alternatives for the treatment of Chagas disease, in this study, a set of new amino naphthoquinone derivatives were synthesised and evaluated in vitro on the epimastigote and trypomastigote forms of Trypanosoma cruzi strains (NINOA and INC-5) and on J774 murine macrophages. The design of the new naphthoquinone derivatives considered the incorporation of nitrogenous fragments with different substitution patterns present in compounds with activity on T. cruzi, and, thus, 19 compounds were synthesised in a simple manner. Compounds 2e and 7j showed the lowest IC50 values (0.43 µM against both strains for 2e and 0.19 µM and 0.92 µM for 7j). Likewise, 7j was more potent than the reference drug, benznidazole, and was more selective on epimastigotes. To postulate a possible mechanism of action, molecular docking studies were performed on T. cruzi trypanothione reductase (TcTR), specifically at a site in the dimer interface, which is a binding site for this type of naphthoquinone. Interestingly, 7j was one of the compounds that showed the best interaction profile on the enzyme; therefore, 7j was evaluated on TR, which behaved as a non-competitive inhibitor. Finally, 7j was predicted to have a good pharmacokinetic profile for oral administration. Thus, the naphthoquinone nucleus should be considered in the search for new trypanocidal agents based on our hit 7j.

A New Smoothened Antagonist Bearing the Purine Scaffold Shows Antitumour Activity In Vitro and In Vivo.

The Smoothened (SMO) receptor is the most druggable target in the Hedgehog (HH) pathway for anticancer compounds. However, SMO antagonists such as vismodegib rapidly develop drug resistance. In this study, new SMO antagonists having the versatile purine ring as a scaffold were designed, synthesised, and biologically tested to provide an insight to their mechanism of action. Compound 4s was the most active and the best inhibitor of cell growth and selectively cytotoxic to cancer cells. 4s induced cell cycle arrest, apoptosis, a reduction in colony formation and downregulation of PTCH and GLI1 expression. BODIPY-cyclopamine displacement assays confirmed 4s is a SMO antagonist. In vivo, 4s strongly inhibited tumour relapse and metastasis of melanoma cells in mice. In vitro, 4s was more efficient than vismodegib to induce apoptosis in human cancer cells and that might be attributed to its dual ability to function as a SMO antagonist and apoptosis inducer.

DNA repair, NFKß, and TP53 polymorphisms associated with potentially malignant disorders and oral squamous cell carcinoma in Argentine patients.

OBJECTIVE: An important strategy in cancer prevention is to identify individual susceptibilities for cancer development through the genomic profile. Developing countries such as Argentina have no data on genetic composition. The aim of this study was to evaluate the single nucleotide polymorphisms of genes related to DNA repair (XCCR3, XPD), cell cycle arrest/apoptosis (TP53), and inflammation (NFKß) of patients with precancer and oral cancer and to contribute to recognizing potential risk of developing these pathologies, and incorporate the risk patients into a clinical follow-up program in Córdoba, Argentina. STUDY DESIGN: A cross-sectional study was performed on 140 patients with oral squamous cell carcinoma (OSCC), oral potentially malignant disorders (OPMDs), and controls. Genotyping of single nucleotide polymorphisms was performed using allele-specific polymerase chain reaction or restriction fragment length polymorphism techniques. The variables were evaluated by bivariate and multivariate statistical methods, with P < .05 statistically significant. RESULTS: The multiple correspondence analyses showed that patients with OSCC are clustered with the T allele of XRCC3 T241 M and the C allele of TP53 R72 P, and patients with OPMDs are clustered with the T allele of NFKß-519. CONCLUSION: Our preliminary results showed that the C allele of the Pro72 variant of TP53 was related to OSSC and OPMD, and the T allele of NFKß-519 is related to OPMDs in Argentine patients.

Protein quantification by bicinchoninic acid (BCA) assay follows complex kinetics and can be performed at short incubation times.

Amongst the available methodologies for protein determination, the bicinchoninic acid (BCA) assay highlights for its simplicity, sensitivity, repeatability and reproducibility. Nevertheless, in spite that the general principle behind this methodology is known, there are still unanswered questions regarding the chemistry behind the assay and the experimental conditions commonly employed. The present work explored the kinetics, and the analytical response of the assay to free amino acids, peptides (containing tryptophan and tyrosine), and proteins. Results revealed kinetic profiles characterized by the absence of plateaus, with behaviors depending on the type of the sample. The latter, along with contribution to the BCA index elicited by oxidation products generated at the side chain of tryptophan and tyrosine, as well as pre-oxidized ß-casein, evidenced the presence of complex reaction mechanisms. In spite of such complexity, our results showed that the BCA index is not modulated by the incubation time. This applies for responses producing absorbance intensities (at 562 nm) higher than 0.1. Therefore, we propose that the assay can be applied at shorter incubation times (15 min) than those indicated in manufactures specifications, and usually used by researches and industry (30 min at 37 °C).

Formation and characterization of crosslinks, including Tyr-Trp species, on one electron oxidation of free Tyr and Trp residues by carbonate radical anion.

Dityrosine and ditryptophan bonds have been implied in protein crosslinking. This is associated with oxidative stress conditions including those involved in neurodegenerative pathologies and age-related processes. Formation of dityrosine and ditryptophan derives from radical-radical reactions involving Tyr˙ and Trp˙ radicals. However, cross reactions of Tyr˙ and Trp˙ leading to Tyr-Trp crosslinks and their biological consequences have been less explored. In the present work we hypothesized that exposure of free Tyr and Trp to a high concentration of carbonate anion radicals (CO3˙-), under anaerobic conditions, would result in the formation of Tyr-Trp species, as well as dityrosine and ditryptophan crosslinks. Here we report a simple experimental procedure, employing CO3˙- generated photochemically by illumination of a Co(iii) complex at 254 nm, that produces micromolar concentrations of Tyr-Trp crosslinks. Analysis by mass spectrometry of solutions containing only the individual amino acids, and the Co(iii) complex, provided evidence for the formation of o,o'-dityrosine and isodityrosine from Tyr, and three ditryptophan dimers from Trp. When mixtures of Tyr and Trp were illuminated in an identical manner, Tyr-Trp crosslinks were detected together with dityrosine and ditryptophan dimers. These results indicate that there is a balance between the formation of these three classes of crosslinks, which is dependent on the Tyr and Trp concentrations. The methods reported here allow the generation of significant yields of isolated Tyr-Trp adducts and their characterization. This technology should facilitate the detection, and examination of the biological consequences of Tyr-Trp crosslink formation in complex systems in future investigations.

Promising 2,6,9-Trisubstituted Purine Derivatives for Anticancer Compounds: Synthesis, 3D-QSAR, and Preliminary Biological Assays.

We designed, synthesized, and evaluated novel 2,6,9-trisubstituted purine derivatives for their prospective role as antitumor compounds. Using simple and efficient methodologies, 31 compounds were obtained. We tested these compounds in vitro to draw conclusions about their cell toxicity on seven cancer cells lines and one non-neoplastic cell line. Structural requirements for antitumor activity on two different cancer cell lines were analyzed with SAR and 3D-QSAR. The 3D-QSAR models showed that steric properties could better explain the cytotoxicity of compounds than electronic properties (70% and 30% of contribution, respectively). From this analysis, we concluded that an arylpiperazinyl system connected at position 6 of the purine ring is beneficial for cytotoxic activity, while the use of bulky systems at position C-2 of the purine is not favorable. Compound 7h was found to be an effective potential agent when compared with a currently marketed drug, cisplatin, in four out of the seven cancer cell lines tested. Compound 7h showed the highest potency, unprecedented selectivity, and complied with all the Lipinski rules. Finally, it was demonstrated that 7h induced apoptosis and caused cell cycle arrest at the S-phase on HL-60 cells. Our study suggests that substitution in the purine core by arylpiperidine moiety is essential to obtain derivatives with potential anticancer activity.

Study of the TP53 codon 72 polymorphism in oral cancer and oral potentially malignant disorders in Argentine patients.

The aim of this work was to evaluate the prevalence of TP53Arg72Pro mutations and their possible relationship with oral carcinoma and oral potentially malignant disorders in Argentine patients. A cross-sectional study was performed on 111 exfoliated cytologies from patients with oral cancer (OC), oral potentially malignant disorders (OPMD) and controls. The TP53Arg72Pro mutations were determined using conventional PCR. We evaluated univariate and multivariate study variables, setting p < 0.05. We found: (a) a low frequency of Pro72 variant in control group and a high frequency in OC and OPMD, as well in OC and oral leukoplakia (OL) diagnosis; (b) multivariate association among the TP53CC genotype and females over 45 years with no tobacco nor alcohol habits with oral lichen planus pathology; (c) multivariate association between the TP53GC genotype and males with alcohol and tobacco habits and OC and OL pathologies. Our results showed that the wild-type Arg72variant was related to control patients and Pro72variant was related to OC and OPMD, in Argentine patients.

Hipoglucemia severa secundaria a pentamidina intravenosa en mujer receptora de un trasplante alogénico de progenitores hematopoyéticos / Severe hypoglycaemia secondary to IV pentamidine in a woman receiving an allogeneic stem cell transplant

Las personas tratadas mediante trasplante de progenitores hematopoyéticos (TPH) presentan una predisposición especial a desarrollar infecciones. Los patógenos más frecuentes son la Candida y el Aspergillus, los cuales comportan una elevada morbimortalidad. El tratamiento de elección para la infección por Pneumocystis Jiroveci es trimetoprim-sulfametoxazole (TMP-SMX). La intolerancia a TMP-SMZ o una situación de mielosupresión, situación habitual en el paciente receptor de TPH, precisan en ocasiones del uso de pentamidina. Durante su administración, intravenosa o inhalada, debe ser monitorizada la glucosa, puesto que han sido reportadas alteraciones de los niveles de glucosa en sangre. Son escasos los pacientes que precisan prescripción de pentamidina intravenosa, pero debido al alto riesgo de hipoglucemia severa, su administración requiere de un protocolo de cuidado específico. El objetivo del presente caso clínico es dar a conocer el protocolo de dieta hiperfraccionada en el paciente sometido a trasplante hematopoyético durante el tratamiento con dicho fármaco

Those patients receiving a stem cell transplant (SCT) as treatment will present a particular tendency to develop infections. The most frequent pathogens are Candida and Aspergillus, which entail a high morbimortality rate. The treatment of choice for infection by Pneumocystis Jiroveci is Trimethoprim/sulfamethoxazole (TMP/SMX).Lack of tolerability to TMP-SMX or myelosuppression, which is a common situation among patients receiving a SCT, will sometimes require the use of pentamidine. During its administration, either intravenous or inhaled, glucose levels must be monitored, because there have been reports about alterations of the levels of glucose in blood. There are few patients who require a prescription of intravenous pentamidine, but due to the high risk of severe hypoglycaemia, its administration requires a specific protocol of care. The objective of the present clinical case is to create awareness about the protocol for hyperfractionated diet in patients undergoing stem cell transplant, during treatment with said drug

Monitoreo bacteriológico del instrumental utilizado en la clínica de ortodoncia

Objetivo: Monitorear bacteriológicamente instrumental metálico y no metálico utilizado en Ortodoncia. Materiales y métodos: El trabajo fue realizado en área Ortodoncia, Facultad de Odontología, UNC. Se estudiaron 15 protocolos de limpieza, descontaminación y esterilización aplicados a 10 juegos de instrumental metálico (alicates de uso intraoral tipo Weingart y How recto) y 10 de elementos acrílicos (retractores de mejillas intraorales). Para el instrumental metálico: la limpieza se realizó utilizando detergente bi o trienzimático; la desinfección con ortoftalaldehído 0,55% o glutaraldehído 2,5% y se esterilizó en autoclave, estufa o esterilizador a bolitas de cuarzo. En un protocolo se limpió el instrumental con alcohol y se llevó a esterilizador de bolitas de cuarzo. Para instrumental no metálico: se realizó limpieza con detergentes bi o trienzimáticos, desinfección con ortoftalaldehído 0,55% o glutaraldehído 2,5%. En un protocolo se aerolizó con glutaraldehído al 2,5% y se enjuagó; y en otro protocolo la desinfección se realizó con hipoclorito de sodio al 1%...

ABSTRACT: Objective: To monitor bacteriologically metallic and non metallic instrument used in clinical care of Orthodontic. Methods: The study was carried out on area Orthodontics, Faculty of Dentistry, National University of Córdoba; 15 protocols for cleaning, decontamination and sterilization were studied ; they were applied to 10 sets of metal instrumental (pliers ) and 10 sets of acrylic elements (intraoral cheek retractors). For the metal instrumental: cleanup was performed using bi or trienzimatic detergent; disinfection was performed with 0.55% ortho-phthalaldehyde or 2.5% glutaraldehyde; sterilization was made by autoclaved, stove or quartz beads sterilizer. In one protocol instrumental was cleaned with alcohol and then took sterilizer quartz beads. For nonmetallic instrumental: we used bi or trienzimatics detergent for cleaning; disinfection with 0.55% ortho-phthalaldehyde or 2.5%. glutaraldehyde ; in one protocol instrumental was aerosolized with 2.5% glutaraldehyde and then rinsed; in one protocol the disinfection was performed with sodium hypochlorite 1%...

Malignancy risk models for oral lesions

OBJECTIVES: The aim of this work was to assess risk habits, clinical and cellular phenotypes and TP53 DNA changes in oral mucosa samples from patients with Oral Potentially Malignant Disorders (OPMD), in order to create models that enable genotypic and phenotypic patterns to be obtained that determine the risk of lesions becoming malignant. STUDY DESIGN: Clinical phenotypes, family history of cancer and risk habits were collected in clinical histories. TP53 gene mutation and morphometric-morphological features were studied, and multivariate models were applied. Three groups were estabished: a) oral cancer (OC) group (n=10), b) oral potentially malignant disorders group (n=10), and c) control group (n=8).RESULTS: An average of 50% of patients with malignancy were found to have smoking and drinking habits. A high percentage of TP53 mutations were observed in OC (30%) and OPMD (average 20%) lesions (p=0.000). The majority of these mutations were GC TA transversion mutations (60%). However, patients with OC presented mutations in all the exons and introns studied. Highest diagnostic accuracy (p=0.0001) was observed when incorporating alcohol and tobacco habits variables with TP3 mutations. CONCLUSIONS: Our results prove to be statistically reliable, with parameter estimates that are nearly unbiased even for small sample sizes. Models 2 and 3 were the most accurate for assessing the risk of an OPMD becoming cancerous. However, in a public health context, model 3 is the most recommended because the characteristics considered are easier and less costly to evaluate (AU)

Malignancy risk models for oral lesions.

OBJECTIVES: The aim of this work was to assess risk habits, clinical and cellular phenotypes and TP53 DNA changes in oral mucosa samples from patients with Oral Potentially Malignant Disorders (OPMD), in order to create models that enable genotypic and phenotypic patterns to be obtained that determine the risk of lesions becoming malignant. STUDY DESIGN: Clinical phenotypes, family history of cancer and risk habits were collected in clinical histories. TP53 gene mutation and morphometric-morphological features were studied, and multivariate models were applied. Three groups were estabished: a) oral cancer (OC) group (n=10), b) oral potentially malignant disorders group (n=10), and c) control group (n=8). RESULTS: An average of 50% of patients with malignancy were found to have smoking and drinking habits. A high percentage of TP53 mutations were observed in OC (30%) and OPMD (average 20%) lesions (p=0.000). The majority of these mutations were GC TA transversion mutations (60%). However, patients with OC presented mutations in all the exons and introns studied. Highest diagnostic accuracy (p=0.0001) was observed when incorporating alcohol and tobacco habits variables with TP3 mutations. CONCLUSIONS: Our results prove to be statistically reliable, with parameter estimates that are nearly unbiased even for small sample sizes. Models 2 and 3 were the most accurate for assessing the risk of an OPMD becoming cancerous. However, in a public health context, model 3 is the most recommended because the characteristics considered are easier and less costly to evaluate.

[Predictive models for complex diseases]. / Modelo predictivo para enfermedades complejas.

UNLABELLED: The Non Communicable Complex Disease (NCCD) are the leading causes of death in the world, causing more deaths each year than all other combined causes. The approximately 80% of deaths were caused by NCCD and occured in low and middle income countries. However, NCCD deaths could be avoided by prevention programs and early diagnosis. The challenge of the multifactorial phenotypes is to achieve a valid strategy for identifying risk individuals at the population. These strategies may be addressed to screening population or generating causal predictive models for early detection, interpreting the root causes that create the condition. The aim of this paper is to describe the characteristic of complex chronic diseases and some of the current methods of study of these in the health area . CONCLUSIONS: Interdisciplinary work, a team of health professionals belonging to different areas allows for an adequate management of complex diseases. The application of graph models, such as DAG's, is a valuable tool for a better adjustment of the statistical model, which allows an appropriate correspondence with the actual health model of these illnesses. And the best methodological strategy for complex diseases is the early diagnosis and the monitoring of risk groups and therapy monitoring of patients diagnosed.

Monitoreo bacteriológico del instrumental utilizado en la práctica clínica de ortodoncia / Bacteriologic monitoring of the instruments used in orthodontic clinical practice

El objetivo del trabajo fue verificar la efectividad de procedimientos de esterilización en el instrumental de ortodoncia el objetivo del trabajo fue verificar la efectividad de procedimientos de esterilización en instrumental de ortodoncia. Seesterilizaron 10 juegos de instrumentos compuestos por alicates How recto, alicates Weingart, alicates de corte, retractores acrílicos, bastones de ligaduras elastoméricas y rollos decadenas elastoméricas. esterilización previa al trabajo: en autoclavelos alicates, en óxido de etileno los elementos plásticos y elastoméricos. Post esterilización in situ: alicates enesterilizador a bolitas de cuarzo; elementos elastoméricos y plásticos aerolizados en glutaraldehido al 2 por ciento. Se tomaron muestras con tubos de hisopos estériles, en dos momentos, 1: previo a la atención al paciente y 2: después de esterilización in situ. los tubos con turbidez macroscópica se colorearon con gram y cultivaron en medios de maC ConKey y Clde. Para cuantificar la carga microbiana, se realizaron tres siembras por estrías con ansa calibrada. momento 1: se encontrócontaminación con Corynebacterium en alicates Weingart y con Staphylococcus coagulasa negativo en los rollosde cadena.momento 2: contaminación con Corynebacterium en retractores; con Staphylococcus coagulasa negativo en alicates de corte, en retractores acrílicos, en bastones de ligadura;con Micrococcus en alicates How rectos. La presencia de cargas bacterianas no satisfactorias sugiere que los procedimientos habituales de esterilización no fueron eficaces.

Monitoreo bacteriológico del instrumental utilizado en la práctica clínica de ortodoncia / Bacteriologic monitoring of the instruments used in orthodontic clinical practice

El objetivo del trabajo fue verificar la efectividad de procedimientos de esterilización en el instrumental de ortodoncia el objetivo del trabajo fue verificar la efectividad de procedimientos de esterilización en instrumental de ortodoncia. Seesterilizaron 10 juegos de instrumentos compuestos por alicates How recto, alicates Weingart, alicates de corte, retractores acrílicos, bastones de ligaduras elastoméricas y rollos decadenas elastoméricas. esterilización previa al trabajo: en autoclavelos alicates, en óxido de etileno los elementos plásticos y elastoméricos. Post esterilización in situ: alicates enesterilizador a bolitas de cuarzo; elementos elastoméricos y plásticos aerolizados en glutaraldehido al 2 por ciento. Se tomaron muestras con tubos de hisopos estériles, en dos momentos, 1: previo a la atención al paciente y 2: después de esterilización in situ. los tubos con turbidez macroscópica se colorearon con gram y cultivaron en medios de maC ConKey y Clde. Para cuantificar la carga microbiana, se realizaron tres siembras por estrías con ansa calibrada. momento 1: se encontrócontaminación con Corynebacterium en alicates Weingart y con Staphylococcus coagulasa negativo en los rollosde cadena.momento 2: contaminación con Corynebacterium en retractores; con Staphylococcus coagulasa negativo en alicates de corte, en retractores acrílicos, en bastones de ligadura;con Micrococcus en alicates How rectos. La presencia de cargas bacterianas no satisfactorias sugiere que los procedimientos habituales de esterilización no fueron eficaces.(AU)

Estudio citomorfométrico de pacientes con cáncer y desórdenes potencialmente malignos de la cavidad bucal / Citomorphometric study of patients with cancer and potentially malignant disorders of the oral cavity

La detección temprana de lesiones bucales promete aumentar sobrevivencia y reducir la morbilidad de los pacientes que sufren esta condición. Un método alternativo para el examen de lesiones en la cavidad bucal, es la citología. Objetivo: valorar las relaciones del tamaño núcleo/citoplasma de células de mucosa bucal sana, de lesiones bucales potencialmente malignas y de cáncer bucal, obtenidas con citología exfoliativa utilizando citomorfometría. Material y método: Se realizó citología a 22 pacientes, de ambos sexos, con edades entre 23 y 81 años utilizando cytobrush. Las muestras se dividieron en tres grupos: 1) citologías de pacientes con lesiones de cáncer bucal (n=7); 2) citologías de pacientes con desórdenes bucales potencialmente malignos (leucoplasia y líquen) (n=15); 3) citologías del lado sano de pacientes con lesiones de cáncer y desórdenes bucales potencialmente malignos (grupo control) (n=15). Se seleccionaron 30 células de cada paciente y se midió el área nuclear (AN), la citoplasmática (AC) y se calculó la relación AN/AN. Se utilizó el Test de Kruskal Wallis y el Sofware estadístico Infostat. Resultados: No se encontraron diferencias significativas entre los tres grupos estudiados al valorar la relación AN/AC. Teniendo en cuenta el género, se observó que en las mujeres se diferenciaron significativamente las células del grupo control de las de los grupos de lesiones. En el género masculino se observaron diferencias significativas entre los tres grupos celulares. No hubo diferencias significativas entre los diferentes grupos etarios .Discusión: A pesar de las diferencias significativas entre los géneros, no es posible hacer una buena separación de los tres grupos de estudio, utilizando solamente citología exfoliativa.

Early detection of bucal lesions promises to increase survival and to reduce morbidity in patients suffering from this condition. An alternative method for examining lesions in the bucal cavity is cytology. Objective: To assess by cytomorphometry the relationship of size nucleus / cytoplasm of superficial cells from healthy bucal mucosa, from potentially malignant bucal disordes lesions and bucal cancer using exfoliative cytology. Material and methods: PAP smear was performed in 22 patients of both gender, aged between 23 and 81. Cytobrush was used. The samples were divided into three study groups: 1) smears of patients with bucal cancer lesions (n = 7), 2) smears of patients with potentially malignant bucal disordes lesions (n = 15), lesions considered were leukoplakia and lichens ; 3) (control group) (n=15): smears of the healthy side of patients with cancer and potentially malignant bucal disordes lesions.Thirty cells were selected for each patient and the nuclear area (NA), cytoplasmic area (CA) were measured and the ratio NA / CA was calculated. We used Kruskal Wallis and Statistical Software InfoStat. Results: No significant differences were found between the three groups studied the relationship NA / CA was assesed . When comparing cells from each of the three groups considering the gender of the patients separately, we found that in women differ significantly from the control group cells and groups of injuries, we could not discriminate between cells obtained from potentially malignant bucal disordes lesions and cancer lesions . In the male gender differences were significant among the three cell groups. Discusion: Despite the significant gender differences, we could not difference the three study groups using only exfoliative cytology.

Efectos de un blanqueamiento dental con ozono y otro con peróxido de carbamida al 22% sobre la fuerza de adhesión al esmalte en diferentes intervalos de tiempo

El objetivo del presente estudio fue demostrar que los efectos del blanqueamiento dental con Ozono sobre el esmalte son de menor duración en comparación con el Peróxido de Carbamida. Veintidós dientes bovinos fueron divididos en tres grupos: Control y dos grupos experimentales (Peróxido de Carbamida- PC y Ozono - Oz). Los dientes del grupo control no fueron blanqueados y se almacenaron en saliva artificial 24 horas antes. Los dientes de los grupos experimentales fueron expuestos a una aplicación diaria del agente blanqueador por una semana. Después de cada aplicación los dientes se almacenaron en saliva artificial, la que se removió cada tres días. En la superficie vestibular se levantó un bloque de resina a los 0, 1, 7, 14, y 21 días después del blanqueamiento, 24 horas después se midió la fuerza de adhesión. Los datos se analizaron con el test de ANOVA y el post test de Tukey (α=0.05) Los resultados mostraron que existe una diferencia estadísticamente significativa en 0 y 1 días después de realizado el blanqueamiento en ambos grupos, luego de una semana la fuerza de adhesión del grupo Oz fue similar a la del control; mientras que los valores del grupo PC fueron bajos incluso después de tres semanas.

The objective of this study was to demonstrate that effects of ozone bleaching on enamel bond strength have a shorter duration in comparison with carbamide peroxide. Twenty two bovine teeth were divided in three groups: Control and two experimental groups (Carbamide Peroxide-CP and Ozone-OZ). Teeth of control group were not submitted to bleaching and were stored in artificial saliva solution at 37° C for 24 hours. Teeth of experimental groups were exposed to one daily application of the bleaching agent for one week. After each treatment teeth were stored in artificial saliva solution, which was changed every three days. A resin composite block was built-up with Stae and Glacier 0, 1, 7, 14, 21 days post bleaching and microtensile bond strength (µTBS) was carried out 24 hours after adhesive-composite application. Data were analyzed by ANOVA and Tukey post hoc test (α=0.05). Results showed that bond strength were significantly different 0 and 1 day after both bleaching treatments. After one week post-ozone bleaching, bond strength returned to that of the untreated control group. Values for CP group were not suitable even three weeks post-bleaching.

Early phenotypic and genotypic alterations in submandibular gland oncogenesis in rats.

The present study evaluates the phenotypic and genotypic changes that take place during early oncogenesis. The submandibular glands of male rats were injected with a 0.5% solution of 9,10-dimethyl-1,2-benzanthracene (DMBA) in acetone. Gland samples were taken at 0, 7, 30 and 150 days post-injection and submitted to histological, biochemical, immunocytochemical and PCR evaluation. Histopathological analysis was performed on hematoxylin-eosin stained slides. Total protein content was assessed by Lowry's method and the protein profile was analyzed by 12% SDS-PAGE. Bcl-2 was demonstrated by silver-enhanced gold immunolabeling. p53 immunolabeling was performed using the streptavidin-biotin system. All the treated animals developed carcinoma-like lesions at 30 and 150 days. Total protein concentration rose significantly (p < 0.05) above control values at 7, 30 and 150 days. The treated glands exhibited positive immunolabeling for p53 in the nuclei of neoplastic cells at 30 and 150 days. Treated glands also showed positive cytoplasmic immunolabeling for Bcl-2, exhibiting statistically significant differences between 7, 30 and 150 days (p = 0.0015), and with controls (p < 0.0001). No p53 mutations were observed whereas a point mutation, C-to-A, of the Bcl-2 gene was detected at 7, 30 and 150 days by PCR amplification. This mutation led to a single aminoacid change (thre --> asn) in the protein molecule. Our results suggest that the early histopathological changes correspond to quantitative and qualitative protein changes. The histopathological, biochemical, immunocytochemical and genetic alterations observed during the course of experimental carcinogenesis in the submandibular gland of the rat could constitute reproducible indices of malignant transformation applicable to human oncogenesis, given the high degree of homology between the oncogenes of mice, rats and human beings.

Valuation of exfoliative cytology as prediction factor in oral mucosa lesions.

The aim of this study was immunolabeling oncoproteins Ck14, p53, p21 and Bcl-2 in order to evaluate their expression in premalignant and malignant stomatological lesions in oral epithelial, and to compare this expression with exfoliative cytology alterations in the same patients. It was studied biopsies and cytologies of 13 subjects with oral lichen planus, with or without Human Papilloma Virus (HPV), leukoplakia and squamous cell carcinoma clinically diagnosed and confirmed by anatomopathological studies. The oral lichen planus lesion presented binuclei orange cells; and in leukoplakia lesions only orange stained was observed; meanwhile koilocytes, inflammatory cells, enlarge nuclear volume and pathogenic microorganisms were observed in the HPV infections and squamous cells carcinoma (SCC). The Ck14, p53, p21 and Bcl-2 proteins were found modified in the leukoplakia, oral lichen planus and cancer. Cytological alterations and positive immunolabeling or over-expression of Ck14 cytokeratine in the upper epithelial stratus should be indicator of malignant transformations as doing subsequence exams.