Orientador: Morgana Rodrigues Guimarães Stabili / Resumo: As chalconas são um grupo de compostos fenólicos derivados de plantas, com diversas propriedades biológicas. Em função dos seus efeitos farmacológicos, diferentes derivados chalcônicos sintéticos, baseados em seus análogos naturais, têm sido investigados como agentes terapêuticos. Estudos clínicos e pré-clínicos têm demonstrado sua efetividade no tratamento de doenças inflamatórias como câncer e artrite, e em patologias ósseas como osteoporose e tumores ósseos. Considerando suas propriedades biológicas e com objetivo de identificar compostos que possam atuar no tratamento de doenças ósseo inflamatórias, avaliamos a habilidade de um novo composto chalcônico, a Chalcona T4, de suprimir a inflamação e osteoclastogênese em um modelo de doença periodontal. No estudo in vivo, um ensaio de toxicidade em camundongos demonstrou que a administração de diferentes doses da chalcona T4 (5, 50, 100 e 200 mg/kg) por um período de 15 dias, via intragástrica, diariamente, não causou alterações físicas ou comportamentais. Análise histopatológica do rim, fígado e estômago destes animais também indicaram ausência de toxicidade em todas as doses avaliadas. Determinada a ausência de toxicidade, periodontite foi experimentalmente induzida em ratos pela colocação de ligaduras ao redor dos primeiros molares inferiores. Chalcona T4 foi administrada diariamente por gavagem intragástrica em duas doses (5 e 50 mg/kg) durante 15 dias. Ao final do período experimental, as amostras contendo tecido gengival ... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

No description available.

Orientador: / Resumo: O objetivo deste estudo foi avaliar o aumento ósseo vertical em seios maxilares preenchidos com o β-TCP em duas granulações de diferentes dimensões e comparar o seu comportamento biológico ao do osso autógeno. Três grupos de 06 seios maxilares: (G1) correspondente ao osso autógeno, (G2) β-TCP com partículas de 0,5 mm a 0,7 mm e (G3) β-TCP com 0,1 mm a 0,5 mm foram avaliados por meio de análise histomorfométrica e imunoistoquímica após 6 meses do preenchimento sinusal. A neoformação óssea em G1, G2 e G3 foi de respectivamente 78,442 µm2, 71,283 µm2 e 64,508 µm2, sem diferença estatisticamente significante (p=0,314). A maior área de tecido conjuntivo foi observada em G3, com 124,265 µm2, seguido por G2, 112,993 µm2 e G1, 112,652 µm2 com ausência de diferença estatística na comparação dos grupos (p=0,366). A área de biomaterial remanescente foi observada em G2 com 9,268 µm2, seguido por G3, 6,021 µm2, e G1, 1,195 µm2, sendo ausente a diferença estatística entre os grupos (p=0,120). A imunomarcação para RUNX2 apresentou-se leve em G1 e G2 e moderada a intensa em G3, enquanto para VEGF foi moderada em G1 e G2 e pouco mais intensa em G3. Conclui-se que o β-TCP nas diferentes granulações mostrou-se osteocondutor e pode ser utilizado com critérios, em pequenos defeitos, em substituição ao osso autógeno. / Mestre

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21147号 / 農博第2273号 / 新制||農||1058(附属図書館) / 学位論文||H30||N5121(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 北山 兼弘, 教授 小杉 緑子, 教授 北島 薫 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Bovine bone grafts (BBX) require protein removal as part of the manufacturing process to reduce antigenicity and, in consequence, to be safely used in humans. Deproteinisation may have direct effects on the characteristics of the bone material and on in vivo material performance. This research aimed to comprehensively study the physicochemical and mechanical properties of BBX processed at low deproteinisation processing temperatures. Cubes of bovine bone (8 mm3) were treated with temperatures between 100 °C and 220 °C at 30 °C intervals and with pressures ranging from 1.01 to 24.58 Bar. The samples were characterised topographically and mechanically using scanning electron microscopy (SEM), atomic force microscopy (AFM), and uniaxial bending tests. The organic content and the chemical composition were determined using thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR). X-ray diffraction (XRD) and FTIR were also used to quantitatively determine the specimen crystallinity. Increasing temperature/pressure was associated with decreasing protein levels and compressive strength and increasing surface irregularities and crystallinity. The findings suggest that low-temperature processed bone is likely to exhibit a rapid in vivo degradation rate. The deproteinisation temperature can be adjusted to tailor the graft properties for specific applications.

In the United States, osteoporosis results in about 1.5 million annual fractures, costing approximately $15 billion. Calcitonin is safe and effective in slowing osteoporotic bone loss, but its effect is transient. The current studies were designed to explore the dose-dependent effects of salmon calcitonin on bone turnover in ovariectomized rats and to determine if the decrease in therapeutic effectiveness of calcitonin demonstrated over time with higher doses is due to oversuppression of bone turnover. Doses of 5, 15, & 50 IU/kg BW/day of calcitonin were compared to placebo in 12-week-old ovariectomized and sham-ovariectomized Sprague-Dawley rats for 24 weeks. The spinal bone mineral content (BMC) as measured by DXA in ovariectomized subjects receiving 5 & 15 IU/kg of calcitonin was not significantly different from sham-ovariectomized subjects, while spinal BMC of subjects receiving 50 IU/kg was significantly lower than shamovariectomized subjects (p<0.05). Femoral BMC of ovariectomized subjects was significantly lower than sham-ovariectomized subjects (p<0.05), but no significant differences were noted between treatment groups. Scanning electron microscopy (SEM) demonstrated a decrease in number and density of trabeculae and in cortical thickness when comparing femurs from ovariectomized with sham-ovariectomized subjects. SEM of subjects receiving 50 IU/kg displayed greater bone loss than other groups. No significant differences were noted between groups for levels of urinary helical peptides or serum pyridinoline [ELISA], indicators of bone resorption. Urinary calcium excretion [capillary ion electrophoresis] was significantly higher in subjects receiving 50 IU/kg of calcitonin than other ovariectomized subjects (p<0.05). Serum levels of osteocalcin [RIA], an indicator of bone formation, were significantly higher in subjects receiving 5 IU/kg of calcitonin than control subjects and those receiving 50 IU/kg (p<0.05). Production of antibodies to calcitonin [ELISA] by subjects in this study did not correlate with changes in bone turnover or bone density. The results of this study do not provide evidence higher doses of calcitonin result in oversuppression of bone turnover. However, urinary calcium excretion affected bone resorption in a reverse dose-dependent manner, suggesting the calciuric effect may be responsible for less effective outcomes seen with higher doses of calcitonin.

Indiana University-Purdue University Indianapolis (IUPUI) / External apical root resorption (EARR) is a common complication of orthodontic treatment. Genetic factors account for approximately 50% of the variation in EARR. Data have indicated variation in histological root resorption associated with orthodontic force (RRAOF) among different inbred strains of mice. Differences in expression of RANKL and OPG were investigated in two strains of mice with different susceptibility to RRAOF using irnmunohistochemistry. Increased localization of RANKL was detected in the tissues surrounding the root of the susceptible strain compared to the resistant strain and the controls. In contrast, increased localization of OPG was found in the tissues surrounding the roots in the resistant A/J strain compared to the susceptible DBA/2J strain. We conclude that differences in the expression of these key bone resorption mediators play a role in determining RRAOF susceptibility. Changes in serum TRAP 5b level in response to orthodontic force were investigated among female A/J, DBA/2J and BALB/cJ mice. The three strains differed in their TRAP positive cell numbers as well as their serum TRAP 5b level at baseline and when treated. A significant increase in the serum TRAP 5b level with treatment was only detected in the RRAOF susceptible DBA/2J strain, and not in RRAOF resistant strains. Our analysis indicates that differences in osteoclast/odontoclast activity play a role in susceptibility to RRAOF that is genetically determined. Serum TRAP 5b levels have a potential role in screening for individuals with greater susceptibility to root resorption. RRAOF was determined for male and female mice of the A/J, DBA/2J and BALB/cJ strains, as well as A/J x DBA/2J and A/J x BALB/cJ crosses. Sex differences were observed among the BALB/cJ strain only, with females more resistant to RRAOF when compared to males. Fis from the A/J x BALB/cJ cross were resistant suggesting that the A/J have dominant resistance alleles, while Fis from the A/J x DBA/2J cross had RRAOF intermediate between their parental A/J and DBA/2J mice, suggesting a polygenic trait. We concluded that the mode of inheritance of RRAOF in mice was polygenic in nature.

Indiana University-Purdue University Indianapolis (IUPUI) / According to one theory of root resorption, occlusal trauma during orthodontic tooth movement damages the cementum covering the root dentin. The body detects the exposed dentin and seeks to remove it, and the result is root resorption. This experiment will explore an aspect of this theory by quantifying the amount and location of damage in mechanically fatigued teeth. Nine dog mandibles were sectioned at the mandibular symphysis. Each half was mounted in orthodontic resin with the incisors upright and exposed. The block was inserted into a jig and placed into a servohydraulic mechanical testing machine. The left central incisor was fatigue loaded with a 2Hz, 10-90 N sinusoidal force for 100,000 cycles (approximately 14 hours). The right central incisor served as the control. Both specimens were scanned with a micro-CT unit, stained with basic fuchsin, and then sectioned along the sagittal plane. Because the experimental and control specimens were stained before sectioning, only microdamage due to the loading process would be evident in the sections. Microdamage which occurred during the sectioning process would not be stained. Central sections through the long axes of the samples were examined for the presence of microdamage with a light microscope and a micro-CT unit. Based on preliminary findings, two types of staining patterns were measured and recorded. The first was called "diffuse stain" and consisted of large stained areas in the dentinal tubules. Diffuse stain was not associated with any visible features at the dentinocemental junction. The second type of staining pattern was called "stained defects." Stained defects were stained irregularities at the dentinocemental junction. For statistical analysis, the roots were divided into buccal-cervical, buccal-middle, buccal-apical, lingual-cervical, lingual-middle, and lingual-apical regions. Comparisons between the fatigued and non-fatigued teeth for differences in area, length, and depth were made under the generalized estimating equation (GEE) framework applied to normally-distributed data. Because the measurements were not normally distributed, a rank transformation of the measurements was performed before conducting the analyses. Comparisons between the fatigued and non-fatigued teeth for differences in presence or absence of stain or defects were made using Cochran-Mantel-Haenszel tests. Repeatability of the measurements was assessed using intraclass correlation coefficients (ICCs), paired t-tests, and Bland-Altman plots. The ICC's ranged from 0 .85 to 1.00, thus making the repeatability of the measurements generally very good. The statistical analysis showed there were no significant differences between the experimental and control teeth for stained defects or diffuse staining for length, depth, or area measurements. However, analyses comparing the distribution of stained defects and diffuse stain within the control and experimental specimens showed significant differences in the distribution of stained defects within the experimental specimens. In the experimental specimens, the stained defects were distributed in a gradient, with the most in the apical region and progressing to the least amount in the cervical region. In the control specimens, there was only a difference in the stained defects between the cervical and apical regions. This distribution is consistent with the biomechanical model which shows increasing stress moving from the cervical region towards the apex. These results show that the test and control specimens differed in how the stained defects were distributed throughout the root, even though there were no differences in the amount of staining between the control and experimental specimens. Whole tooth and histologic slides were scanned with the micro-CT unit, but the dentinocemental junction could not be delineated enough to make any measurements. No data could be collected regarding microdamage in this area using the micro-CT unit. It was recommended that future studies use a tomography unit with better resolution, use a larger samples size, employ a contrast agent when trying to visualize microdamage with the micro-CT unit, and incorporate a way to measure the intensity of the staining in addition to the location and size.

No description available.

<p>Giant cell tumour of bone (GCT) is an aggressive primary bone tumour with an unclear etiology that presents with significant local osteolysis due in part to the accumulation of multinucleated osteoclast-like giant cells. However, it is the neoplastic spindle-like stromal cells within GCT that largely direct the pathogenesis of the tumour. I hypothesize that parathyroid hormone-related protein (PTHrP) is a key mediator within GCT that promotes the characteristic osteolytic phenotype by stimulating both bone resorption and giant cell formation. The work presented in this thesis collectively demonstrates that the stromal cells express PTHrP and its receptor, the parathyroid hormone type 1 receptor (PTH1R), and that PTHrP acts in an autocrine/paracrine manner within the tumour to stimulate expression of factors that promote bone resorption. Data are presented that demonstrate that PTHrP stimulates stromal cell expression of the receptor activator of nuclear factor-κB ligand (RANKL), a known essential regulator of osteoclastogenesis, which results in increased formation of multinucleated cells from murine monocytes. Moreover, the GCT stromal cells express matrix metalloproteinase (MMP)-1 and MMP-13. These results suggest that the stromal cells may participate directly in bone resorption through the degradation of type I collagen, the promotion of osteoclast activity, or through a combination of these elements. PTHrP also regulates the expression of MMP-13 by the stromal cells. Experiments with CD40 ligand show that local factors present within the tumour can influence PTHrP expression by the stromal cells and potentiate its catabolic effects by stimulation of RANKL and MMP-13 expression. Together, this thesis presents evidence that suggests PTHrP is an important factor in the pathophysiology of GCT by its actions on promoting catabolism within the tumour. The role of PTHrP in normal physiology and the mechanisms of action presented here suggest that research into the effects of PTHrP within GCT may provide invaluable information that enhances our understanding of the biology of this particularly aggressive bone tumour.</p> / Doctor of Philosophy (PhD)