Resistencia a fratura de pre-molares restaurados com compositos odontologicos em diferentes configurações cavitarias

Orientador : Luis Roberto M. MartinsDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O objetivo deste trabalho foi avaliar a resistência à compressão e o padrão de fratura de pré-molares humanos em função do tipo de configuração cavitária (inlay e onlay), restaurados com dois tipos de compósitos odontológicos. Assim, foram utilizados compósito microhíbrido indicado para uso laboratorial (Solidex, Shofu) e compósito de uso universal (Filtek Z250, 3M/ESPE). Foram utilizados 84 dentes pré-molares superiores humanos, divididos em sete grupos com doze amostras cada. Os grupos ficaram assim definidos: Gl: dentes que não receberam preparos cavitários (controle); G2: preparos inlays restaurados com Filtek Z250 fotoativada com dupla intensidade de, luz (Degulux/Degussa); G3: preparos inlays restaurados com Filtek 2250 fotoativada indiretamente com aparelho de alta intensidade de luz (EDG-IuxlEDG); G4: preparos inlays restaurados com Solidex fotoativada com aparelho de alta intensidade de luz; G5: preparos onlays restaurados com Filtek 2250 fotoativada com dupla intensidade de luz; G6: preparos onlays restaurados com Filtek 2250 fotoativada com alta intensidade de luz e G7: preparos onlays restaurados com Solidex fotoativada com alta intensidade de luz. A resistência à fratura foi determinada para cada amostra, através de carregamento vertical com esfera de 6mm de diâmetro, à velocidade de 0,5 mmlmin em máquina de ensaio universal (Instron). As amostras foram analisadas, classificando-se o padrão de fratura em quatro níveis: I - fratura apenas do dente (GR 1) ou da restauração, envolvendo simplesmente a substituição da restauração sem necessidade de extensão do preparo; II - fratura da restauração envolvendo pequena porção do dente, caracterizando-se pela necessidade de ligeira extensão do preparo; lU - fratura com envolvimento periodontal, mas com possibilidade de restauração com recobrimento de cúspides ou aumento de coroa; IV -fratura com envolvimento periodontal com necessidade de exodontia do elemento dental. As médias do carregamento necessárias para fraturar as amostras em cada grupo foram (em kgf): G1= 124,00 (B); G2= 113,52 (B); G3= 117,08 (B); G4= 119,80 (B); G5= 160,33 (AB); G6= 197,81 (A); G7= 131,22 (B). Os valores de resistência à fratura foram submetidos à análise de variância e, em seguida, foi aplicado o teste de Tukey (p<0,05) que revelou diferenças entre os grupos. Assim, pode-se concluir que os dentes com preparos tipo onlay restaurados com compósito Filtek 2250 apresentaram média de resistência à fratura média estatisticamente superior aos dentes restaurados com compósito Solidex ou dentes íntegros. Além disso, não houve diferença estatística significativa entre os dentes com preparos inlays restaurados com Filtek 2250 ou Solidex e dentes íntegros. Em relação ao padrão de fratura, as médias do teste de Kruskal-Wallis apresentaram diferença estatística significativa segundo os grupos: G1: C; G2: AB; G3: AB; G4: AB; G5: A; G6: AB; G7: B. Os dentes com restaurações inlays (Filtek 2250 e Solidex) e onlays de Filtek 2250 apresentaram padrões de fratura mais destrutivos, não sendo possível observar diferença estatística significativa entre esses grupos. Os dentes com restaurações onlay em Solidex apresentaram padrão de fratura menos destrutivo em relação aos demais grupos, com exceção do grupo controleAbstract: The aim of this study was to evaluate the fracture strength and the fracture pattem of human pre-molars with inlay and onlay cavity preparations restored with two hybrid composite resins and light cured in a direct and indirect technique. Eighty-four premolars were selected and divided into seven experimental groups of twelve specimens each: G1 = teeth without cavity preparation (control); G2 = inlay/Z250 (directly light cured with Soft - start technique); G3 = inlay/Z250 (indirectly light cured with a high intensity light curing unit); G4 = inlay/indirect Solidex (indirectly light cured with a high intensity light curing unit); G5 = onlay/Z250 direct (directly light cured with Soft - start technique); G6 = onlay/ Z250 (indirectly light cured with a high intensity light curing unit); G7 = onlay / Solidex (indirectly light cured with a high intensity light curing unit). All specimens were submitted to an axial compression loading in an Instron Machine, with a 6.0mm diameter sphere, at a speed of O.5mm/min. The fractured teeth were analyzed and classified according to four levels offracture pattem: 1- fracture only in the tooth (Gl) or only in the restoration, which could be simply solved by the substitution of the restoration, without extending the preparation; II - fracture of the restoration and of a small portion of the tooth, with necessity of a preparation extend; III - fracture with periodontal involvement, with restoration possibility with cuspid protection; IV - fracture with periodontal involvement, with tooth removal needing. The mean values of fracture strength were (kgf): Gl=124.00(B); G2=113.52(B); G3=117.08(B); G4=119.80(B); G5=160.33(AB); G6=197.81(A); G7=131.22(B). According to ANOV A (p<O,O5) there was statistical significant difference among the groups, that were identified by the Tukey test. According to the results, it could be concluded that teeth with onlay preparation restored with Z250 composite resin showed statistically higher mean values of fracture strength than teeth with the same preparation restored with SoIidex resin and teeth of the controI group. There was no statisticaI difference in the fracture resistance values among the teeth with inIay preparations restored with Z250, SoIidex and the controI group. In order to verify the differences of fracture pattem, the KruskaI- Wallis test was applied, and the following statistical significant differences were observed: G1: C; G2:AB; G3: AB; G4: AB; G5: A; G6: AB; G7: B. Teeth with inIay preparations restored with both resins and teeth with onlay preparations restored with Z250 showed more catastrophic ttacture pattems. However, a statisticaI significant difference among was not observed among these groups. Teeth with onIay preparations restored with SoIidex resin presented a less destructive fracture pattern when compared to the other groups, excepting the controI grouMestradoDentísticaMestre em Clínica Odontológic

Biohydrogenation of 22:6n-3 by Butyrivibrio proteoclasticus P18

Background: Rumen microbes metabolize 22:6n-3. However, pathways of 22:6n-3 biohydrogenation and ruminal microbes involved in this process are not known. In this study, we examine the ability of the well-known rumen biohydrogenating bacteria, Butyrivibrio fibrisolvens D1 and Butyrivibrio proteoclasticus P18, to hydrogenate 22:6n-3. Results: Butyrivibrio fibrisolvens D1 failed to hydrogenate 22:6n-3 (0.5 to 32 mu g/mL) in growth medium containing autoclaved ruminal fluid that either had or had not been centrifuged. Growth of B. fibrisolvens was delayed at the higher 22:6n-3 concentrations; however, total volatile fatty acid production was not affected. Butyrivibrio proteoclasticus P18 hydrogenated 22:6n-3 in growth medium containing autoclaved ruminal fluid that either had or had not been centrifuged. Biohydrogenation only started when volatile fatty acid production or growth of B. proteoclasticus P18 had been initiated, which might suggest that growth or metabolic activity is a prerequisite for the metabolism of 22:6n-3. The amount of 22:6n-3 hydrogenated was quantitatively recovered in several intermediate products eluting on the gas chromatogram between 22:6n-3 and 22:0. Formation of neither 22:0 nor 22:6 conjugated fatty acids was observed during 22:6n-3 metabolism. Extensive metabolism was observed at lower initial concentrations of 22:6n-3 (5, 10 and 20 mu g/mL) whereas increasing concentrations of 22:6n-3 (40 and 80 mu g/mL) inhibited its metabolism. Stearic acid formation (18:0) from 18:2n-6 by B. proteoclasticus P18 was retarded, but not completely inhibited, in the presence of 22:6n-3 and this effect was dependent on 22:6n-3 concentration. Conclusions: For the first time, our study identified ruminal bacteria with the ability to hydrogenate 22:6n-3. The gradual appearance of intermediates indicates that biohydrogenation of 22:6n-3 by B. proteoclasticus P18 occurs by pathways of isomerization and hydrogenation resulting in a variety of unsaturated 22 carbon fatty acids. During the simultaneous presence of 18:2n-6 and 22:6n-3, B. proteoclasticus P18 initiated 22:6n-3 metabolism before converting 18:1 isomers into 18:0

Prenatal origin of childhood AML occurs less frequently than in childhood ALL

Background While there is enough convincing evidence in childhood acute lymphoblastic leukemia (ALL), the data on the pre-natal origin in childhood acute myeloid leukemia (AML) are less comprehensive. Our study aimed to screen Guthrie cards (neonatal blood spots) of non-infant childhood AML and ALL patients for the presence of their respective leukemic markers. Methods We analysed Guthrie cards of 12 ALL patients aged 2–6 years using immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements (n = 15) and/or intronic breakpoints of TEL/AML1 fusion gene (n = 3). In AML patients (n = 13, age 1–14 years) PML/RARalpha (n = 4), CBFbeta/MYH11 (n = 3), AML1/ETO (n = 2), MLL/AF6 (n = 1), MLL/AF9 (n = 1) and MLL/AF10 (n = 1) fusion genes and/or internal tandem duplication of FLT3 gene (FLT3/ITD) (n = 2) were used as clonotypic markers. Assay sensitivity determined using serial dilutions of patient DNA into the DNA of a healthy donor allowed us to detect the pre-leukemic clone in Guthrie card providing 1–3 positive cells were present in the neonatal blood spot. Results In 3 patients with ALL (25%) we reproducibly detected their leukemic markers (Ig/TCR n = 2; TEL/AML1 n = 1) in the Guthrie card. We did not find patient-specific molecular markers in any patient with AML. Conclusion In the largest cohort examined so far we used identical approach for the backtracking of non-infant childhood ALL and AML. Our data suggest that either the prenatal origin of AML is less frequent or the load of pre-leukemic cells is significantly lower at birth in AML compared to ALL cases

The Enzymatic Activity of Type 1 Iodothyronine Deiodinase (D1) is Low in Liver Hemangioma: A Preliminary Study

Type 1 iodothyronine deiodinase (D1) is a crucial enzyme which converts the prohormone thyroxine (T4) into active tri-iodothyronine (T3). There has been strong evidence that the metabolism of thyroid hormones is disturbed in some neoplastic tissues such as thyroid, renal, and breast cancer. However, there are few available data about D1 enzyme activity in benign tumors such as hemangioma, which is the most common primary liver tumor. Hence this study aimed to determine the enzymatic activity of D1 in hemangiomas in relation to healthy liver tissue. Seven tumors and healthy control tissues were obtained from patients who had liver resection due to hemangioma. The activity was assessed by measurement of radioactive iodine released by deiodination catalyzed by D1. It was found that D1 activity was significantly lower in the hemagiomas than in the healthy surrounding tissue (p = 0.0017). The results indicated that thyroid hormones play important roles not only in the regulation of cell metabolism, but also in cell growth, division, and apoptosis. The active form T3 acts through its nuclear receptors and influences the up- and down-regulation of target genes. Healthy liver tissue expresses a high level of D1, but disturbed D1 activity may result in changes in the local concentration of T3 which may impair gene transcription. These finding demonstrate a low enzymatic activity of D1 in liver hemangioma and suggest an as yet unknown role of thyroid hormones in this type of benign liver tumor

GM2-gangliosidosis B1 variant: analysis of beta-hexosaminidase alpha gene mutations in 11 patients from a defined region in Portugal.

The GM2-gangliosidosis B1 variant occurs at an exceptionally high frequency in the northern part of Portugal. In most patients, the disease manifests itself as a juvenile form, as opposed to the late-infantile form described for many patients from other parts of the world. We have analyzed the beta-hexosaminidase alpha gene in 11 patients, as well as in some relatives, in order to characterize the underlying abnormalities. They were screened for the two previously identified mutations responsible for the B1 variant phenotype (G533----A, also designated as the "DN allele," and C532---T) by PCR amplification of an 800-bp DNA fragment and subsequent dot-blot hybridization with allele-specific oligonucleotides. The fragment amplified from one patient was also subcloned and sequenced. Ten patients, constituting a clinically and biochemically homogeneous group, were found to be homozygous for the DN allele. The other, whose clinical profile more resembled the late-infantile phenotype often described in the literature, was a compound heterozygote carrying the DN allele and another, as yet unidentified, abnormal allele. Our results, corroborated by previously published data, suggest that homozygotes and compound heterozygotes for the DN allele may be distinguishable at the phenotypic level, depending on the nature of the abnormality in the other allele. A common ancestral origin for the DN allele can also be postulated

A Technique for Measuring Petal Gloss, with Examples from the Namaqualand Flora

The degree of floral gloss varies between species. However, little is known about this distinctive floral trait, even though it could be a key feature of floral biotic and abiotic interactions. One reason for the absence of knowledge is the lack of a simple, repeatable method of gloss measurement that can be used in the field to study floral gloss. A protocol is described for measuring gloss in petal samples collected in the field, using a glossmeter. Repeatability of the technique is assessed. We demonstrate a simple yet highly accurate and repeatable method that can easily be implemented in the field. We also highlight the huge variety of glossiness found within flowers and between species in a sample of spring-blooming flowers collected in Namaqualand, South Africa. We discuss the potential uses of this method and its applications for furthering studies in plant-pollinator interactions. We also discuss the potential functions of gloss in flowers

Caracterização dos Solos do Entorno das Jazidas do Parque Eólico do Município de Casa Nova, Estado da Bahia.

Este trabalho teve como objetivo contribuir para um melhor conhecimento dos solos da margem esquerda do Rio São Francisco, no entorno do Parque Eólico do município de Casa Nova, BA, principalmente quanto à sua classificação taxonômica e variação de seus atributos físicos e químicos na paisagem, suas limitações e potencialidades agrícolas, além disso, visa contribuir para a realização do zoneamento edáfi co de culturas de interesse local e de orientar o uso e manejo sustentável das terras da área de estudo.bitstream/item/207873/1/SDC292.pd