Simultaneous membrane interaction of amphipathic peptide monomers, self-aggregates and cargo complexes detected by fluorescence correlation spectroscopy.

Peptides able to translocate cell membranes while carrying macromolecular cargo, as cell-penetrating peptides (CPPs), can contribute to the field of drug delivery by enabling the transport of otherwise membrane impermeable molecules. Formation of non-covalent complexes between amphipathic peptides and oligonucleotides is driven by electrostatic and hydrophobic interactions. Here we investigate and quantify the coexistence of distinct molecular species in multiple equilibria, namely peptide monomer, peptide self-aggregates and peptide/oligonucleotide complexes. As a model for the complexes, we used a stearylated peptide from the PepFect family, PF14 and siRNA. PF14 has a cationic part and a lipid part, resembling some characteristics of cationic lipids. Fluorescence correlation spectroscopy (FCS) and fluorescence cross-correlation spectroscopy (FCCS) were used to detect distinct molecular entities in solution and at the plasma membrane of live cells. For that, we labeled the peptide with carboxyrhodamine 6G and the siRNA with Cyanine 5. We were able to detect fluorescent entities with diffusional properties characteristic of the peptide monomer as well as of peptide aggregates and peptide/oligonucleotide complexes. Strategies to avoid peptide adsorption to solid surfaces and self-aggregation were developed and allowed successful FCS measurements in solution and at the plasma membrane. The ratio between the detected molecular species was found to vary with pH, peptide concentration and the proximity to the plasma membrane. The present results suggest that the diverse cellular uptake mechanisms, often reported for amphipathic CPPs, might result from the synergistic effect of peptide monomers, self-aggregates and cargo complexes, distributed unevenly at the plasma membrane.

Saturated Fatty Acid Analogues of Cell-Penetrating Peptide PepFect14: Role of Fatty Acid Modification in Complexation and Delivery of Splice-Correcting Oligonucleotides.

Modifying cell-penetrating peptides (CPPs) with fatty acids has long been used to improve peptide-mediated nucleic acid delivery. In this study we have revisited this phenomenon with a systematic approach where we developed a structure-activity relationship to describe the role of the acyl chain length in the transfection process. For that we took a well-studied CPP, PepFect14, as the basis and varied its N-terminal acyl chain length from 2 to 22 carbons. To evaluate the delivery efficiency, the peptides were noncovalently complexed with a splice-correcting oligonucleotide (SCO) and tested in HeLa pLuc705 reporter cell line. Our results demonstrate that biological splice-correction activity emerges from acyl chain of 12 carbons and increases linearly with each additional carbon. To assess the underlying factors regarding how the transfection efficacy of these complexes is dependent on hydrophobicity, we used an array of different methods. For the functionally active peptides (C12-22) there was no apparent difference in their physicochemical properties, including complex formation efficiency, hydrodynamic size, and zeta potential. Moreover, membrane activity studies with peptides and their complexes with SCOs confirmed that the toxicity of the complexes at higher molar ratios is mainly caused by the free fraction of the peptide which is not incorporated into the peptide/oligonucleotide complexes. Finally, we show that the increase in splice-correcting activity correlates with the ability of the complexes to associate with the cells. Collectively these studies lay the ground work for how to design highly efficient CPPs and how to optimize their oligonucleotide complexes for lowest toxicity without losing efficiency.

Effects of cargo molecules on membrane perturbation caused by transportan10 based cell-penetrating peptides.

Cell-penetrating peptides with the ability to escape endosomes and reach the target are of great value as delivery vectors for different bioactive cargoes and future treatment of human diseases. We have studied two such peptides, NickFect1 and NickFect51, both originated from stearylated transportan10 (PF3). To obtain more insight into the mechanism(s) of peptide delivery and the biophysical properties of an efficient vector system, we investigated the effect of different bioactive oligonucleotide cargoes on peptide-membrane perturbation and peptide structural induction. We studied the membrane interactions of the peptides with large unilamellar vesicles and compared their effects with parent peptides transportan10 and PF3. In addition, cellular uptake and peptide-mediated oligonucleotide delivery were analyzed. Calcein leakage experiments showed that similar to transportan10, NickFect51 caused a significant degree of membrane leakage, whereas NickFect1, similar to PF3, was less membrane perturbing. The results are in agreement with previously published results indicating that NickFect51 is a more efficient endosomal escaper. However, the presence of a large cargo like plasmid DNA inhibited NickFect's membrane perturbation and cellular uptake efficiency of the peptide was reduced. We conclude that the pathway for cellular uptake of peptide complexes is cargo dependent, whereas the endosomal escape efficacy depends on peptide hydrophobicity and chemical structure. For small interfering RNA delivery, NickFect51 appears to be optimal. The biophysical signature shows that the peptide alone causes membrane perturbation, but the cargo complex does not. These two biophysical characteristics of the peptide and its cargo complex may be the signature of an efficient delivery vector system.

Differential endosomal pathways for radically modified peptide vectors.

In the current work we characterize the uptake mechanism of two NickFect family members, NF51 and NF1, related to the biological activity of transfected plasmid DNA (pDNA). Both vectors condense pDNA into small negatively charged nanoparticles that transfect HeLa cells with equally high efficacy and the delivery is mediated by SCARA3 and SCARA5 receptors. NF1 condenses DNA into less homogeneous and less stable nanoparticles than NF51. NF51/pDNA nanoparticles enter the cells via macropinocytosis, while NF1/pDNA complexes use clathrin- or caveolae-mediated endocytosis and macropinocytosis. Analysis of separated endosomal compartments uncovered lysomotropic properties of NF51 that was also proven by cotransfection with chloroquine. In summary we characterize how radical modifications in peptides, such as introducing a kink in the structure of NF51 or including extra negative charge by phospho-tyrosine substitution in NF1, resulted in equally high efficacy for gene delivery, although this efficacy is achieved by using differential transfection pathways.

Intranasal Insulin for the Treatment of Persistent Post-COVID-19 Olfactory Dysfunction.

OBJECTIVE: To investigate if intranasal insulin could be a treatment option for those suffering from recalcitrant olfactory dysfunction due to COVID-19. STUDY DESIGN: Prospective interventional cohort with a single group. SETTING: Sixteen volunteers with anosmia, severe hyposmia, or moderate hyposmia for more than 60 days as sequelae of severe acute respiratory syndrome coronavirus 2 infections were selected for the study. All volunteers reported that standard therapies, such as corticosteroids, have failed to improve their olfactory function. METHODS: Olfactory function was assessed by the Chemosensory Clinical Research Center test of olfaction (COT) before and after the intervention. Changes in qualitative, quantitative, and global COT scores were investigated. The insulin therapy session consisted of placing into each olfactory cleft 2 pieces of gelatin sponge soaked with neutral protamine Hagedorn (NPH) insulin, 40 IU on each side. The procedure was repeated twice a week for 1 month. Glycaemic blood level was measured before and after each session. RESULTS: The qualitative COT score rose 1.53 points, p = .0001, 95% confidence interval (CI) (-2.12 to -0.94). The quantitative COT score increased by 2.00 points, p = .0002, 95% CI (-3.59 to -1.41). Global COT score had an improvement of 2.01 points, p = .00003, 95% CI (-2.7 to -1.3). Glycaemic blood level dropped on average 10.4 mg/dL, p < .00003, 95% CI (8.1-12.8). CONCLUSION: Our results suggest that the administration of NPH insulin into the olfactory cleft yields a rapid improvement in the sense of smell of patients suffering from persistent post-COVID-19 olfactory dysfunction. Moreover, the procedure seems to be safe and tolerable.

Prevalence of respiratory epithelial adenomatoid hamartomas (REAH) associated with nasal polyposis: an epidemiological study - how to diagnose.

OBJECTIVES: To highlight the prevalence of respiratory epithelial adenomatoid hamartomas in the olfactory cleft of patients with nasal polyposis. To demonstrate characteristics indicative of hamartoma on the CT scans of paranasal sinuses during surgery and in histopathological exams. METHODS: Cross-sectional study carried out in Hospital das Clínicas da UFMG and Núcleo de Otorrino BH. We performed 114 nasal endoscopic surgeries for polyposis, between February 2015 and November 2019. We assessed the olfactory cleft width in all preoperative CT scans. Upon seeing an indication of hamartoma on the CT scan, we took a tissue sample from the olfactory cleft during the surgery and sent for histopathological exam. We referred the samples to a pathologist experienced in the anatomopathological diagnosis of respiratory epithelial adenomatoid hamartomas. RESULTS: Of the 114 patients with polyposis, 54 (47.4%) had olfactory cleft enlargement and, 100% of them had tissue with a dense and hardened polypoid aspect, with a slight cerebriform appearance in this region during the surgery. Histology confirmed a respiratory epithelial adenomatoid hamartoma. CONCLUSION: This observation suggests that the presence of hamartomas in polyposis is common, but underdiagnosed. LEVEL OF EVIDENCE: Step 3 (Level 3).

The role of soybean extracts and isoflavones in hormone-dependent breast cancer: aromatase activity and biological effects.

Estrogen receptor-positive (ER+) breast cancer is the most common cause of cancer death in women worldwide. Nowadays, the relationship between soya diet and breast cancer is controversial due to the unknown role of its isoflavones, genistein (G) and daidzein (D). In this work, we investigated not only the anti-tumor properties of a soybean extract (NBSE) but also whether the biotransformation of extract (BSE) by the fungus Aspergillus awamori increased its effectiveness. The BSE showed a stronger anti-aromatase activity and anti-proliferative efficacy in ER+ aromatase-overexpressing breast cancer cells. D and G were weak aromatase inhibitors, but inhibited cancer cell growth, being G the isoflavone that contributed to the BSE-induced effects. This work demonstrated that the biotransformation increased the anti-aromatase activity and the anti-tumoral efficacy of soybean extract in breast cancer cells. Moreover, it elucidated the potential use of soya in the prevention and/or treatment of ER+ breast cancer.

Prevalence of respiratory epithelial adenomatoid hamartomas (REAH) associated with nasal polyposis: an epidemiological study - how to diagnose

Abstract Objectives: To highlight the prevalence of respiratory epithelial adenomatoid hamartomas in the olfactory cleft of patients with nasal polyposis. To demonstrate characteristics indicative of hamartoma on the CT scans of paranasal sinuses during surgery and in histopathological exams. Methods: Cross-sectional study carried out in Hospital das Clínicas da UFMG and Núcleo de Otorrino BH. We performed 114 nasal endoscopic surgeries for polyposis, between February 2015 and November 2019. We assessed the olfactory cleft width in all preoperative CT scans. Upon seeing an indication of hamartoma on the CT scan, we took a tissue sample from the olfactory cleft during the surgery and sent for histopathological exam. We referred the samples to a pathologist experienced in the anatomopathological diagnosis of respiratory epithelial adenomatoid hamartomas. Results: Of the 114 patients with polyposis, 54 (47.4%) had olfactory cleft enlargement and, 100% of them had tissue with a dense and hardened polypoid aspect, with a slight cerebri-form appearance in this region during the surgery. Histology confirmed a respiratory epithelial adenomatoid hamartoma. Conclusion: This observation suggests that the presence of hamartomas in polyposis is common, but underdiagnosed. Level of evidence: Step 3 (Level 3).

pH-responsive PepFect cell-penetrating peptides.

A series of cell-penetrating PepFect peptide analogues was developed by substitutions of the galanin-derived N-terminal sequence. Histidine modifications were incorporated in order to make the peptides pH-responsive. The peptides were all able to form non-covalent complexes with an oligonucleotide cargo by co-incubation in buffer. The complexes were characterized by dynamic light scattering and circular dichroism, and an assay to evaluate the peptide-cargo affinity was developed. Cellular bioactivity was studied in HeLa cells using a luciferase-based splice correction assay. In addition, the membrane interactions of the peptides in large unilammelar vesicles was studied using a calcein leakage assay. The effects of substitutions were found to be dependent of the non-modified, C-terminal sequence of the peptides; for analogues of PepFect 3 we observed an increase in membrane activity and bioactivity for histidine-containing analogues, whereas the same modifications introduced to PepFect 14 lead to a decreased bioactivity. Peptides modified with a leucine/histidine sequence were found to be pH responsive, complexes formed from these peptides were small at pH 7 and grew under acidic conditions. The most promising of the novel PepFect 3 analogues, PepFect 132 has a significantly higher bioactivity and membrane activity than the parent peptide PepFect 3.

Optimization of in vivo DNA delivery with NickFect peptide vectors.

As the field of gene therapy progresses, an increasingly urgent need has arisen for efficient and non-toxic vectors for the in vivo delivery of nucleic acids. Cell-penetrating peptides (CPP) are very efficient transfection reagents in vitro, however, their application in vivo needs improvement. To enhance in vivo transfection we designed various CPPs based on previous knowledge of internalization studies and physiochemical properties of NickFect (NF) nanoparticles. We show that increment of the helicity of these Transportan10 analogues improves the transfection efficiency. We rationally design by modifying the net charge and the helicity of the CPP a novel amphipathic α-helical peptide NF55 for in vivo application. NF55 condenses DNA into stable nanoparticles that are resistant to protease degradation, promotes endosomal escape, and transfects the majority of cells in a large cell population. We demonstrate that NF55 mediates DNA delivery in vivo with gene induction efficiency that is comparable to commercial transfection reagents. In addition to gene induction in healthy mice, NF55/DNA nanoparticles showed promising tumor transfection in various mouse tumor models, including an intracranial glioblastoma model. The efficiency of NF55 to convey DNA specifically into tumor tissue increased even further after coupling a PEG2000 to the peptide via a disulphide-bond. Furthermore, a solid formulation of NF55/DNA displayed an excellent stability profile without additives or special storage conditions. Together, its high transfection efficacy and stability profile make NF55 an excellent vector for the delivery of DNA in vivo.

Therapeutic potential of cell-penetrating peptides.

The ability of cell-penetrating peptides to cross plasma membranes has been used for various applications, including the delivery of bioactive molecules to inhibit disease-producing cellular mechanisms. Selective drug delivery into target cells improves drug distribution and decreases dosing and toxicity. In this review, the authors outline the main challenges in the field, namely clarification of mechanisms of entry into cells, as well as current and future perspectives regarding cell-penetrating peptides application for human therapeutics. Here, the authors discuss some of the factors that influence efficacy of delivery and review the current status of preclinical studies and clinical trials involving the use of cell-penetrating peptide-mediated delivery of therapeutics.

Adolescent idiopathic scoliosis and similar conditions: three-dimensional classification / Escoliose idiopática do adolescente e similares: classificação tridimensional / Escoliosis idiopática del adolescente y afecciones similares: clasificación tridimensional

ABSTRACT Objective: To create a new comprehensive, three-dimensional, applicable classification for Adolescent Idiopathic Scoliosis and similar conditions. Methods: The Three-Dimensional Classification was created with three components: the first, the quantitative factor, divides into three types according to the number of curves; the second, the locator factor defines the most structured point of the curve; and the third, the sagittal factor, evaluates the overall sagittal plane. To test the new classification, we studied the images of 99 patients comparing the intra- and interobserver agreement and reproducibility index of the Three-Dimensional Classification with that of Lenke. Results: It can be stated that, overall, the agreement between the three evaluators in relation to the Three-Dimensional Classification and that of Lenke in this series was considered very good. Conclusions: The case study showed a significant difference in the percentages between the two Classifications. In the evaluation of thoracic kyphosis, the Three-Dimensional Classification defined 26.6% of the cases as hyperkyphosis and 61.6% as normal, whereas the Lenke Classification defined 6.06% as hyperkyphosis and 84.18% as normal. However, in the global comparative analysis of the methods, the Three-Dimensional and Lenke systems presented statistically the same levels of agreement, since the values of the confidence intervals overlap. Level of Evidence II; Retrospective study.

RESUMO Objetivo: Criar uma nova Classificação para escoliose idiopática do adolescente e similares, abrangente, tridimensional e aplicativa. Métodos: Criou-se a Classificação Tridimensional com três componentes: o primeiro denominado de fator quantitativo, que divide-se em três tipos de acordo com o número de curvas; o segundo, o fator localizador evidencia o ponto mais estruturado da curva e o terceiro é o fator sagital que avalia globalmente o plano sagital. Para testar a nova Classificação, estudou-se as imagens de 99 pacientes, comparando o índice de concordância e reprodutibilidade intra e interobservador da Classificação Tridimensional com a de Lenke. Resultados: Pode-se afirmar que, no geral, o índice de concordância dos três avaliadores em relação a Classificação Tridimensional e a de Lenke nessa casuística foi considerada muito boa. Conclusões: O estudo da casuística evidenciou diferenças significativas dos percentuais entre as duas Classificações, referente a avaliação da cifose torácica, a Classificação Tridimensional apresentou 26,6% de hipercifose e normal 61,6%, ao passo que a Classificação Lenke evidenciou 6,06% de hipercifose e 84,18% normal. Contudo, na análise comparativa global, com os métodos Tridimensional e Lenke, apresentou-se estatisticamente os mesmos níveis de concordância, uma vez que os valores dos intervalos de confiança se sobrepõem. Nível de Evidência II; Estudo retrospectivo.

RESUMEN Objetivo: Crear una nueva clasificación abarcadora, tridimensional y de aplicación para escoliosis idiopática del adolescente y afecciones similares. Métodos: La Clasificación Tridimensional se creó con tres componentes: el primero, el factor cuantitativo, se divide en tres tipos según el número de curvas; el segundo, el factor de localización, define el punto más estructurado de la curva, y el tercero, el factor sagital, evalúa el plano sagital general. Para probar la nueva clasificación, estudiamos las imágenes de 99 pacientes comparando el índice de concordancia y reproducibilidad intra e interobservador de la Clasificación Tridimensional con la de Lenke. Resultados: Es posible afirmar que, en general, el índice de concordancia de los tres evaluadores en relación a la Clasificación Tridimensional y la de Lenke en esa casuística fue considerada muy buena. Conclusiones: El estudio de la casuística mostró una diferencia significativa de los porcentuales entre las dos clasificaciones. En la evaluación de la cifosis torácica, la clasificación tridimensional definió 26,6% como hipercifosis y 61,6% como normal, mientras que la Clasificación de Lenke definió el 6,06% como hipercifosis y el 84,18% como normal. Sin embargo, en el análisis comparativo global de los sistemas Tridimensional y Lenke presentaron estadísticamente los mismos niveles de concordancia, ya que los valores de los intervalos de confianza se superponen. Nivel de evidencia II; Estudio retrospectivo.

Differential reactivity of serum immunoglobulins from Brazilian wild mammals to staphylococcal A and streptococcal G proteins.

Human pathogens have evolved to infect vertebrate hosts other than human beings without causing symptoms of the disease, thus permitting them to complete their life cycle and to develop into infectious forms. The identification and management of infected animals are alternatives to control dissemination of the disease and to prevent human illness. In the current study, the potential use of staphylococcal A or streptococcal G proteins was evaluated with enzyme-linked immunosorbent assays (ELISAs) for seroepidemiological studies. Sera were collected from animals that were representative of 23 different Brazilian wild mammals. A high protein A binding rate was observed in all animals, except for the orders Didelphimorphia, Artiodactyla, and Rodentia, in which affinity was medium or low. Affinity for streptococcal G protein was higher in animals of the order Artiodactyla, whereas no streptococcal G protein binding was observed in samples obtained from felines (order Carnivora). Bacterial protein binding to mammalian immunoglobulins was confirmed by immunoblotting. The results suggest that secondary detection systems should be better investigated in ELISA protocols before their implementation in seroepidemiological studies involving wild mammals.

Jogo compulsivo e festa trance: dinheiro, performance, mercado / Not available

A tese resulta de trabalho etnográfico e reporta a duas práticas ocorridas em Portugal: a) o jogo compulsivo como doença e sua definição continuada através da participação em um grupo de autoajuda denominado Famílias Anónimas e b) a festa trance, lugar onde a dança da música eletrônica aí tocada é considerada como o ápice da participação. Apesar do contraste entre estas duas práticas, em ambos são para ser encontradas formas de construção dos lugares de ocorrência - o das reuniões dos Anónimos e o da festa - e formas de participação que se definem pela intensidade; em ambos, o dinheiro vem a representar um importante papel. A participação nos Anônimos é livre, a que corresponde à festa trance releva de um pagamento. Ainda que ambas devam a sua eficiência à repetição de uma fórmula, é feita uma discussão sobre o uso do dinheiro e a importância do mercado, especialmente na definição ambivalente do que é uma mercadoria, como são os casos de drogas como a ganza - aqui, o uso português deste último termo que designa a canábis apenas realça o facto de o texto resultar de trabalho etnográfico - e o LSD, vulgo ácido

The thesis results from ethnographic work and reports two practices that occurred in Portugal: a) compulsive gambling as a disease and its continued definition through participation in a self-help group called Anonymous Families and b) the trance party, a place where electronic music dance is considered as the apex of participation. In spite of the contrast between these two practices, in both are to be found forms of construction of the places of occurrence - that of the meetings of the Anonymous and of the party - and forms of participation that are defined by intensity; in both, money comes to play an important role. Participation in the Anonymous is free, in the trance party there is a payment. Although both of them owe their efficiency to the repetition of a formula, a discussion is made about the use of money and the importance of the market, especially in the ambivalent definition of what a commodity is - as are the cases of drugs such as ganza - here the Portuguese use of the latter term for cannabis only highlights the fact that the text is the result of ethnographic work - and LSD -, the acid

Seasonal Transport of Fine Particles to the Grand Canyon.

Potential sources of pollutants can be identified by analyzing back trajectories associated with extreme ambient concentrations. Conditional frequency analysis (CFA) was used to identify statistically significant associations of geographical regions and ambient air quality observed at sites near the Grand Canyon. Stratification by season reveals a pattern of association during the fall quarter that is not observed during other seasons. Application of CFA to different source tracers provides additional information on the nature of the associations. Tracer species that were often below detection limits can be studied because the method requires only that the highest concentrations be identified.

The Relationship Between Atmospheric Transport and the Particle Scattering Coefficient at the Grand Canyon.

Air trajectory and particle scattering data (bsp) for the period 1984-1989 are used to determine the relationship between atmospheric transport and visual air quality at the Grand Canyon National Park. Using cluster analysis, 72-hour back-trajectories arriving four times per day were grouped into distinct transport patterns. Northwesterly and southerly/southwesterly flow dominate in the winter and summer seasons, respectively. Comparisons of bsp values accompanying different transport patterns showed a clear relationship between air flow pathway and light scattering due to small particles during the non-summer months only. An index is defined which describes the percentage of annual trajectories belonging to specific transport routes delivering predominantly clear air to the GCNP.

Attribution of Particulate Sulfur in the Grand Canyon to Specific Point Sources Using Tracer-Aerosol Gradient Interpretive Technique (TAGIT).

Since aerosol particulate sulfur is generally a secondary airborne pollutant, most source attribution techniques require many assumptions about the transport and chemistry of sulfur dioxide (SO2) emissions. Uncertainties in our understanding of these processes impair our ability to generate reliable attribution information that is necessary for designing cost-effective pollution control policies. A new attribution technique using artificial tracer is presented in hopes of reducing the uncertainty of secondary aerosol source attribution. The Tracer-Aerosol Gradient Interpretive Technique (TAGIT) uses tracer data from a monitoring network to distinguish sites impacted by a source tagged with tracer from nonimpacted sites. Sites determined not to be influenced by the plume are considered to represent background particulate sulfur concentrations. The particulate sulfur attributable to the source at sites within the plume is calculated as the difference between observed and background particulate sulfur. TAGIT is applied to measurements made in the vicinity of the east and west ends of the Grand Canyon in order to attribute particulate sulfur to the sources within the Eastern Colorado River Valley (ECRV) and the Mohave Power Project (MPP), respectively. TAGIT results indicate that during the winter intensive field sampling experiment (January 15-February 13, 1992), an average of 59 + 12% of the particulate sulfur at Marble Canyon, AZ, was attributable to ECRV sources. Similarly, during the summer field sampling experiment (July 13-August 30, 1992), MPP is estimated to have contributed an average of 7 + 3% of the particulate sulfur at Meadview, AZ. Uncertainties associated with the assumptions of TAGIT are discussed and quantified. The attribution results suggest that SO2-to-sulfate conversion rates are highly variable from day to day in this region.

Efeito da ciclagem térmica sobre a resistência de união entre titânio comercialmente puro e um cerômero / Effect of thermocliccling on the bond strenght between a pure commecially titanium and ceromer

Objetivo: Verificar, por ensaio mecânico de cisalhamento, oefeito da termociclagem na resistência de união entre o titâniocomercialmente puro (Ticp) e um material para revestimentoestético (Resilab Wilcos/Brasil). Método: Vinte cilindrosmetálicos, com 5mm de comprimento e 4mm de diâmetro cada,foram obtidos por meio de usinagem de barras de titânio. Asbases metálicas foram então jateadas com óxido de alumínio(250 μm), com pressão de 20 bar durante 20 segundos a umadistância de 3cm. Em seguida, foi aplicado sobre as basesmetálicas o sistema adesivo Resibond (Wilcos/Brasil), seguidoda resina Resilab opaca e de revestimento estético. Asamostras foram armazenadas em água destilada por 24 horas,a 37C e em seguida divididos aleatoriamente em dois grupos(n=10): o G1 (controle) e o G2 (experimental), sendo estesubmetido a 500 ciclos térmicos (5º/55ºC±1, tempo de imersãode: 30 s). Os dois grupos foram submetidos ao ensaio decisalhamento em máquina de ensaio universal (modelo DL-1000 Equip. e Sist. Ltda., São José dos Pinhais - PR - Brasil)com célula de carga de 500 Kgf e velocidade de 0,5 mm/min. Osvalores numéricos (MPa) foram submetidos ao teste estatísticode Mann-Whitney (p=0,038). Resultados: Após análise dosdados, observou-se que o grupo G1 (7,83-18,72) diferiuestatisticamente de G2 (5,51-15,34). Conclusão: Baseado nosresultados é lícito concluir que houve uma diminuiçãosignificante na resistência adesiva após termociclagem.

Correlação entre espessura gengival nos enxertos gengivais livres na determinação do "creeping attachment" / Correlation between gingival thickness in the free gingival grafts in the determination of the creeping attachment

Foi avaliada a relação da espessura do enxerto gengival livre com o potencial desta margem gengival migrar em direção coronal (Creeping Attachment) em pacientes com indicação para este tipo de cirurgia, fazendo uma correlação com as distâncias biológicas. As cirurgias de enxerto gengival autógeno livre foram realizadas em 34 pacientes da Universidade Federal de Goiás (num total de 65 dentes), sendo onze do sexo masculino e vinte e três do feminino. As cirurgias foram realizadas sem o objetivo de recobrimento radicular. Na avaliação inicial foram tomadas as medidas pré-operatórias relativas à profundidade do sulco gengival, recessão gengival e quantidade e espessura da gengiva queratinizada e nível de inserção. As mesmas medidas realizadas na avaliação inicial foram repetidas após trinta dias, 3 e 6 meses e 1 ano pós-operatórios. Os resultados mostraram correlação estatísticamente significante entre a espessura do enxerto e o "Creeping Attachment". Esses resultados sugerem que houve influência decisiva da espessura gengival na determinação das características da gengiva queratinizada resultante, com redução da recessão gengival e posicionamento coronal da margem gengival. No entanto, a ocorrência e a quantidade exata de "Creeping Attachment" não é previsível e não são conhecidos todos os fatores envolvidos.