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The subject of whether fluorine (F) is detrimental to human health has been controversial for many years. Much of the discussion focusses on the known benefits and known detriments to dental care and problems that fluorine causes in bone structure at high doses. It is therefore desirable to have the means to monitor fluorine concentrations in the human body as a means to directly assess exposure. A monitoring tool could be applied in studies of human health and perhaps answer some of the questions regarding levels at which fluorine has protective effects and negative health consequences. This thesis presents work in the further development of a low risk non-invasive method for the monitoring of fluorine in human bone. The work was based on the technique of neutron activation analysis (NAA). Fluorine accumulates in bone as a long term storage site following exposure. In this thesis, the McMaster Tandem accelerator was used to produce neutrons through the 7Li(p,n)7Be reaction, measuring F levels in the human hand bone using IVNAA. The gamma rays emitted through the 19F(n,γ )20F reaction are measured using nine NaI(Tl) detectors with 4π geometry. Four published papers are presented in this thesis. The main outcome of the first publication was the development of a new phantom. This was needed to reduce the aluminum contamination. The main outcome of the second publication was a series of improvements to the method for the in vivo measurement of bone fluorine using NAA of the new phantoms. In the third publication the best hand position and neutron flux map in the irradiation cavity were determined through both Monte Carlo simulation (FLUKA) and experimental methods. Finally, the fourth publication describes the utility of the improved technique in a pilot study of environmentally exposed people. The overall conclusion from this thesis work is that a low risk monitoring tool, based on an NAA technique, has been developed which is capable of monitoring fluorine in urban Canadians. The technique can now be applied in studies of human health. / Thesis / Doctor of Philosophy (PhD)

Aluminum is a neurotoxin and has been recognized as a causative agent for dialysis encephalopathy and renal osteodystrophy, as well as possibly being related to Alzheimer's disease. General public exposures to aluminum have increased in the modern, industrial age stimulating scientists to inquire into the degree of risk associated with such widespread use of aluminum. Aluminum is thought to be stored in bone, therefore, development of an in vivo method for the determination of aluminum a in human bone, suitable for routine monitoring of patients and population is the goal of this study. Using neutron activation analysis, low-energy neutrons are produced on the KN accelerator inducing the 27Al(n,y)28AI reaction in an irradiated site. Two different shapes (cylindrical and flat) of aluminum doped tissue equivalent phantoms, simulating both bone and soft tissue, have been built. Calibration lines, detection limits and doses delivered with the different shapes of phantom have been discussed, and compared to the previously published results. Two detection systems. an assembly of two large Nal{Tl) detectors and a hyperpure germani Jm detector, have been compared as well. The results achieved suggest that this technique may provide an alternative choice to painful bone biopsy for the in vivo monitoring of aluminum intoxication from long-term exposure. / Thesis / Master of Science (MS)

This paper presents research on isolated human remains from Grasshopper Pueblo and analyzes the processes by which bone becomes displaced from burials. Isolated human bone has never been systematically examined, which represents a significant gap in the study of the prehistoric American Southwest. This research is important because it is the first determination of the pattern of isolated bone found at an archaeological site and the formation processes that are responsible. It is also relevant for the creation of a standard isolated bone methodology and because it enables a better understanding of burial assemblages and anomalous assemblages of culturally modified bone.Subadults dominate the assemblage and larger elements are better represented than smaller elements. Most of the modifications present are postmortem but perimortem breakage and toolmarks are also present. This research produced a baseline of detailed data on isolated human bone in which patterns and anomalies can be inferred; the results suggest multiple causes of the isolation of the specimens, including prehistoric cultural disturbance, rodent disturbance, and the process of excavation.

Orientador: Sergio de Toledo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-04T01:47:57Z (GMT). No. of bitstreams: 1 Cruz_GabrielaAlessandrada_M.pdf: 15668447 bytes, checksum: 48a5ee54985687b46e68567ad7b84fbb (MD5) Previous issue date: 2004 / Resumo: Os substitutos ósseos são materiais utilizados em procedimentos periodontais regenerativos como uma alternativa para tratamento de defeitos ósseos. Neste estudo foram avaliados a morfologia, o tamanho e a composição química das seguintes partículas: osso bovino orgânico cortical e esponjoso com partículas microgranular medindo entre 0,25 e 1,0 mm e macrogranular medindo entre 1,0 e 2,0 mm, osso bovino cortical inorgânico com partículas medindo entre 0,25 e 1,0 mm, hidroxiapatita com partículas medindo entre 0,75 e 1,0 mm e osso humano descalcificado, congelado e seco medindo entre 0,25 a 0,5 mm. Para a analise da morfologia e do tamanho das partículas, as amostras foram preparadas em portaespécime, metalizadas em ouro e analisadas a vácuo em microscópio eletrônico de varredura (SEM). Para a análise da composição química, as partículas não foram metalizadas e foram analisadas por microanálise de raio X, por espectroscopia por dispersão de energia (EDS). A análise visual realizada por SEM, demonstrou que as partículas de osso bovino orgânico e inorgânico, osso humano e hidroxiapatita apresentaram formato irregular e tamanho variável, maior do que o mencionado no rótulo pelo fabricante. A análise da composição química realizada por microanálise (EDS) detectou a presença de elementos como: sódio, cálcio e fósforo, que são comuns à composição do tecido ósseo, porém revelaram a presença de elementos químicos nas partículas de osso bovino orgânico. Esses resultados sugerem que o osso bovino orgânico não é composto puramente por colágeno e proteína / Abstract: This article evaluates the morphologic and chemical composition of the following bone substitutes: cancellous and cortical organic bovine bone with micro and macro particles size ranging from 0,25 to 1,0 mm and 1,0 to 2,0 mm respectively, inorganic bovine bone with particles size ranging from 0,25 to 1,0 mm, hydroxyapatite with particles size ranging from 0,75 to 1,0 mm and demineralized freeze-dried bone allograft with particles size raging from 0,25 to 0,5 mm. The samples were coated with gold in an ion coater, the morphology was observed and the measurements of particle size were performed on vacuum condition by scanning electron microscopy (SEM). The chemical composition was evaluated by microanalysis EDS using samples without covering. The SEM analyses provided visual evidence that all materials analyzed have irregular shape and the particle size values were larger than the values mentioned by the manufacturer. The microanalysis EDS detected the presence of sodium, calcium and phosphorus that are common elements of the bone tissue. However, mineral elements were detected in all analyzed particles of organic bovine bone excepting for macro cancellous organic bovine bone. These results suggest that the evaluated organic bovine bone could not be considered a pure organic material / Mestrado / Periodontia / Mestre em Clínica Odontológica

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O termo estrutura cristalina entende-se como um conjunto de átomos periodicamente distribuídos no espaço, formando uma rede. O material composto, osso, contém uma parte orgânica formada por colágeno e uma parte inorgânica formada predominantemente por cristais de hidroxiapatita, que possui fórmula molecular Ca10(PO4)6(OH)2 em sua célula unitária. A estrutura cristalina da hidroxiapatita pode indicar a qualidade de ossos trabeculares, pela identificação do tamanho de cristalito, da microdeformação e da proporção de cálcio e fósforo nos três tipos de ossos: normal, osteopênico e osteoporótico. A osteoporose é definida pelo National Institutes of Health como uma desordem esquelética caracterizada pelo comprometimento da resistência óssea e aumento do risco de fratura. Objetiva-se avaliar e caracterizar a estrutura cristalina da matriz inorgânica de ossos secos trabeculares de vértebras de colunas de cadáveres humanos normais, osteopênicos e osteoporóticos por microscopia ótica, microscopia eletrônica de varredura e espectometria de energia dispersiva e difratometria de raios-X, utilizando o método de refinamento de Rietveld, balizando os resultados com os valores de microdureza. Foram utilizados ossos secos trabeculares de vértebras L1 de colunas de nove cadáveres humanos provenientes do Serviço de Verificação de Óbito da capital. Antes da coleta do material, elas foram pré-divididas em três grupos: normal, osteopênico e osteoporótico, através de ultrassonometria de calcâneo. A caracterização dos três tipos de ossos foi feita pelas técnicas de microscopia ótica, microscopia eletrônica de varredura, microanálise por espectrometria de energia dispersiva, microdureza e difratometria de raios-X pelo método de pó com aplicação do método de Rietveld. Os resultados mostraram uma diminuição dos valores de tamanho do cristalito (de 670 para 213 nanômetros), microdureza (de 30,27 para 21,22 knoop), proporção de cálcio e fósforo (de 2,02 para 1,73), número de trabéculas e densidade óssea e um aumento nos valores de microdeformação (de 5,4 para 16,8), sugerindo uma maior desorganização e fragilidade na estrutura cristalina da hidroxiapatita em ossos osteopênicos e osteoporóticos em relação aos normais. A caracterização microestrutural dos cristais de hidroxiapatita em ossos secos trabeculares permitiu diferenciar os três tipos de ossos (normal, osteopênico e osteoporótico) e complementar a avaliação da osteoporose, com ênfase na qualidade óssea. / The term crystal structure is understood as a set of atoms periodically distributed in space, forming a lattice The composite material, bone, contains a organic part that consists of collagen and a inorganic part that consists predominantly of hydroxyapatite crystals, having molecular formula Ca10(PO4)6(OH)2 in its unit cell. The crystal structure of hydroxyapatite can indicate the trabecular bone quality, by the identification of crystallite size, microstrain and ratio of calcium and phosphorus in bones of three types: normal, osteopenic or osteoporotic. Osteoporosis is defined by the National Institutes of Health as a skeletal disorder characterized by compromised bone strength and increased risk of fracture. The objective is to evaluate and characterize the crystalline structure of the inorganic matrix of dry trabecular bones of vertebral column of normal, osteopenic and osteoporotic human cadavers by optical microscopy, scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, using the Rietveld refinement method and microhardness. Dried trabecular bone of vertebrae L1 columns of nine human cadavers from the Serviço de Verificação de Óbito of the capital were used. Before sample collection, they were pre-divided into three groups: normal, osteopenic or osteoporotic, through Quantitative ultrasound of the calcaneus. The characterization of the three types of bones were made by optical microscopy, scanning electron microscopy, microanalysis by energy dispersive spectrometry, microhardness and powder X-ray diffraction with application of the Rietveld method. The results showed a decrease of the crystallite size (from 670 to 213 nanometers), hardness (from 30,27 to 21,22 knoop), ratio of calcium and phosphorus (from 2,02 to 1,73), trabecular number and bone density and an increase in microstrain values (from 5,4 to 16,8) suggesting greater fragility and disruption in the crystalline structure of hydroxyapatite in osteopenic and osteoporotic bone compared to normal. Microstructural characterization of hydroxyapatite crystals in dry trabecular bone could differentiate the three types of bones (normal, osteopenic and osteoporotic) and supplement assessment of osteoporosis, with an emphasis on bone quality.

Bone marrow (BM) mesenchymal stem cells (MSC) support proliferation and differentiation of hematopoietic progenitor cells (HPC) in vitro. Since they represent a rare subset of BM cells, MSC preparations for clinical purposes involves a preparative step of ex vivo multiplication. The aim of our study was to analyze the influence of culture duration on MSC supportive activity. MSC were expanded for up to 10 passages. MSC and CD34+ cells were seeded in cytokinefree co-cultures after which the phenotype, clonogenic capacity and in vivo repopulating activity of harvested hematopoietic cells were assessed. Early passage MSC supported HPC expansion and differentiation toward both B lymphoid and myeloid lineages. Late passage MSC did not support HPC and myeloid cell outgrowth but maintained B cell supportive ability. In vitro maintenance of NOD/SCID mouse repopulating cells cultured for one week in contact with MSC was effective until the fourth MSC passage and declined afterwards. CD34+ cells achieved higher levels of engraftment in NOD/SCID mice when co-injected with early passage MSC; however MSC expanded beyond 9 passages were ineffective in promoting CD34+ cell engraftment. Non-contact cultures indicated that MSC supportive activity involved diffusible factors. Among these, interleukin (IL)-6 and IL-8 contributed to the supportive activity of early passage MSC but not of late passage MSC. MSC phenotype as well as fat, bone and cartilage differentiation capacity did not change during MSC culture. Extended MSC culture alters their supportive ability toward HPC without concomitant changes in phenotype and differentiation capacity.

Dental implants are an effective alternative for the replacement of missing teeth. The success of the implant depends on how well a bone heals around the implant, a process known as osseointegration. However, excessive heat generated during the bone drilling will cause cell death and may prevent osseointegration of the implant, resulting in early failure. There are many factors which contribute to the heat generation during drilling. Experiments were carried out to investigate the affect of variable drilling factors on heat generation during drilling operation. Natural bone is not an ideal material for such research, as it varies widely in density and other parameters of interest.. It would be desirable to have a more uniform and consistent material to use in such studies. However, such a material must be similar to bone to allow the results to be extrapolated to the clinical situation. The current study describes and validates a model for use in such studies. Polymethylmethacrylate (PMMA) is the material chosen for our studies. A theoretical model was developed to study the effect of different drilling parameters on temperature rise during drilling operations. Comparison of observed results obtained from experiments was made with the results from theoretical study. Comparison of results for PMMA and human bone are also shown explaining how PMMA material can be substituted for human bone. The results suggest that the PMMA model is an acceptable surrogate for bone in such studies.

Low back pain is a common cause of disability and work inability, often associated with intervertebral disc degeneration. The current understanding of disc degeneration is limited and none of the available treatments is entirely effective. The work described herein investigates potential strategies for the biological herapeutic restoration of disc degeneration. Firstly, an in vitro study to investigate the effects of BMP-7 on human discal cellular viability was performed. Cultured cells were treated with TNF-a or H202 to induce apoptosis, resulting in the down regulation of extracellular matrix proteins, decreased cell viability, morphological changes and activation of caspase-3; however, addition of BMP-7 alone prevented the observed effects, demonstrating the ability of BMP-7 to prevent apoptosis of human disc cells in vitro. Secondly, the differentiation potential of stem cells towards disc-like cells was studied. Rodent mesenchymal stem cells (rMSCs) were cultured alone or co-cultured with rat disc tissue. Differentiation potential of rMSCs was evaluated by mRNA and protein expression, cellular function and morphological studies. The co-culture conditions led to the expression of chondrocytic markers in rMSCs, whereas rMSCs cultured alone did not express the chondrocytic markers. Cellular contact between the co-cultured rMSCs and the discal tissue were observed. This study demonstrated that rMSCs can differentiate into functional disc-like cells in a tissue influenced co-culture environment. Finally, the survival and differentiation of CD34+ or CD34?? bone marrow (hBM) cells, in an intra-discal xenogeneic transplantation rat model was investigated. Human CD34+ or CD34?? cells were isolated, fluorescent-labelled and injected into rat coccygeal discs. The survival of transplanted cells was confirmed by fluorescent positive cells as well as a human nuclear specific marker. Interestingly, CD34?? cells survived until day 42 in the injected discs, and differentiated into cells ex:pressing a chondrocytic phenotype. In contrast, CD34+ cells could not be detected by day 21. This data suggests that transplanted hBM CD34?? cells, in contrast to CD34+ cells, were able to survive and differentiate within the intervertebral disc. Together, the results of these studies can both encourage and contribute to the basis of potential biological therapies in the restoration of intervertebral disc degeneration.