¿A qué pregunta responde "el hueso"?: una cuestión de direccionalidad estructural y organización biológica (hueso y huesos, del big-bang a la osteoporosis) / To which question is 'bone' the answer?: a matter of structural directionality and biological organization (bone and bones, from the big bang to osteoporosis)

La "razón de ser" de nuestros huesos y esqueletos constituye un dilema centralizado en los conceptos biológicos de "estructura" y "organización", cuya solución necesitamos comprender para interpretar, diagnosticar, tratar y monitorear correctamente las osteopatías fragilizantes. Últimamente se ha reunido conocimiento suficiente para proponer aproximaciones razonables a ese objetivo. La que exponemos aquí requiere la aplicación de no menos de 6 criterios congruentes: 1) Un criterio cosmológico, que propone un origen común para todas las cosas; 2) Un criterio biológico, que explica el origen común de todos los huesos; 3) Un enfoque epistemológico, que desafía nuestra capacidad de comprensión del concepto concreto de estructura y del concepto abstracto de organización, focalizada en la noción rectora de direccionalidad espacial; 4) Una visión ecológica, que destaca la importancia del entorno mecánico de cada organismo para la adecuación de la calidad mecánica de sus huesos a las "funciones de sostén" que les adjudicamos; 5) Una correlación entre todo ese conocimiento y el necesario para optimizar nuestra aptitud para resolver los problemas clínicos implicados y 6) Una jerarquización del papel celular en el manejo de las interacciones genético-ambientales necesario para asimilar todo el problema a una simple cuestión de organización direccional de la estructura de cada hueso. Solo aplicando estos 6 criterios estaríamos en condiciones de responder a la incógnita planteada por el título. La conclusión de esta interpretación de la conducta y función de los huesos debería afectar el fundamento de la mayoría de las indicaciones farmacológicas destinadas al tratamiento de la fragilidad ósea. (AU)

The nature of the general behavior of our bones as weight-bearing structures is a matter of two biological concepts, namely, structure and organization, which are relevant to properly interpret, diagnose, treat, and monitor all boneweakening diseases. Different approaches can be proposed to trace the corresponding relationships. The one we present here involves six congruent criteria, namely, 1) a cosmological proposal of a common origin for everything; 2) a biological acknowledgement of a common origin for all bones; 3) the epistemological questioning of our understanding of the concrete concept of structure and the abstract notion of organization, focused on the lead idea of directionality; 4) the ecological insight that emphasizes the relevance of the mechanical environment of every organism to the naturally-selected adjustment of the mechanical properties of their mobile bones to act as struts or levers; 5) The clinical aspects of all the alluded associations; 6) The central role of bone cells to control the genetics/ environment interactions of any individual as needed to optimize the directionality of the structure of each of his/her bones to keep their mechanical ability within physiological limits. From our point of view, we could only solve the riddle posed by the title by addressing all of these six criteria. The striking conclusion of our analysis suggests that the structure (not the mass) of every bone would be controlled not only to take care of its mechanical ability, but also to cope with other properties which show a higher priority concerning natural selection. The matter would be that this interpretation of bone behavior and 'function' should affect the rationales for most pharmacological indications currently made to take care of bone fragility. (AU)

Bone healing after biodegradable mini-plate fixation

ABSTRACT PURPOSE: To compare bone healing in mandibular vertical body osteotomies (MVBO) after fixation with a resorbable 2.0mm-profile fixation system in the first and third postoperative months in rabbits. METHODS: Twenty hemimandibles of ten rabbits were divided into two groups according to duration of resorbable fixation-one or three months. The MVBOs were performed and one four-hole, resorbable, 2.0mm mini-plate fixation system was used on each side. The computed tomography (CT) scans, scanning electron microscopy (SEM), and histomorphometric outcomes of groups I and II were compared. RESULTS: Significant differences were found between the one- and three- month assessments in terms of newly formed bone ratio values (p<0.05). There was more new bone formation at the third month on both the CT and histomorphometric examinations. A better adaptation of the bone tissues to the resorbable mini-plate and screws was observed on SEM at three months. CONCLUSION: The resorbable mini-plates provided a fixation stable enough to allow immediate oral alimentation and callus formation in both groups.

Histological study on the effect of nicotine administration on the bone of adult male albino rat and the possible protective role of vitamin E

Cigarette smoking is one of the major problems affecting the health of humans. Many studies have been conducted on different organs of the body, but only a few have been conducted on the effect of cigarette smoking on bone. Vitamin E is a potent antioxidant supplement that might alleviate these hazardous effects on bone. The aim of our study was to evaluate the effect of nicotine on bone and whether the addition of vitamin E could protect the bone against nicotine-induced effects. Forty-five animals were used and divided into three groups comprising 15 animals each. Group I served as the control group. Animals in group II received nicotine. Animals in group III received nicotine in addition to vitamin E. At the end of the experiment the animals were sacrificed and the femur bone specimens were dissected and processed. The specimens were subjected to histological study: H and E and scanning electron microscopy. Evaluation of bone mineral density using energy dispersive X-ray was also carried out. Statistical analysis was carried out for all data recorded. Animals of group II showed thinning out of compact bone and trabeculae of cancellous bone of the proximal end of the femur. An increase in adipocytes in adjacent bone marrow was also detected. Cracking and microfracture of bone were apparent, as well as irregular endosteal pores. There was decrease in calcium content in the bone. Group III showed improvement in the morphology of bone and mineral content. Statistical analysis confirmed these results. We concluded that nicotine has hazardous effects on bone, and vitamin E has a protective role against nicotine

Effect of atorvastatin on phenytoin-induced osteoporosis in adult albino rats: a pharmacological and light and electron microscopic study

Phenytoin, an antiepileptic drug [AED], might affect bone structure and mineralization. Epileptic patients who take AEDs are at increased risk for falls and fractures. Therefore, there is a need for a new approach to increase bone health in these patients. This study was conducted to assess the efficacy of statins in preventing bone loss associated with AEDs. Thirty male adult albino rats were divided into five equal groups. The animals, which received daily treatment by gastric gavage for 5 weeks, were classified into: group I [the control group]; group II, in which the rats were given phenytoin 20 mg/kg bw; group III, in which rats received phenytoin as in group II with atorvastatin 5 mg/kg bw; group IV, in which rats were given phenytoin along with atorvastatin 10 mg/kg bw; and group V, in which they were given phenytoin along with atorvastatin 20 mg/kg bw. Biochemical assays, assessment of bone mineral density, light [LM] and scanning electron microscopic studies [SME], as well as morphometric and statistical studies were carried out. The present work demonstrated that atorvastatin in a dose-dependent manner significantly [P<0.001] prevented the decrease in serum and bone calcium and phosphorus and bone-specific alkaline phosphatase due to phenytoin administration. There was also a graded improvement in osteocalcin [a marker for osteoblastic activity] and TRAP [a marker for osteoclastic activity] levels. Moreover, atorvastatin significantly inhibited the loss in bone weight, volume, and density. On LM and SEM examination, atorvastatin showed a gradual improvement of the tibia bone with higher doses as there was a significant increase [P<0.05] in trabecular and cortical bone thickness and a significant decrease [P<0.05] in osteoclast numbers per area of bone surface in the metaphysis; compared with the phenytoin-only-treated group, an improvement was seen in the growth of the epiphyseal plate. Atorvastatin could be considered a beneficial drug for treatment of osteoporosis in epileptic patients on phenytoin

Early osseous tissue formation associated to submerged and non-submerged dental implants: a histomorphometric animal study / Formación temprana de tejido óseo asociado a implantes dentales sumergidos y no sumergidos. Un estudio histomorfométrico animal

The purpose of this research was to compare the bone formation around submerged and non-submerged implants installed in a mandible of dog. Seven beagle dogs were used in this protocol; initially, was performed extraction of posterior teeth of mandible and after 3 month healing were installed two dental implants with surface treatment (subtraction of titanium via acidification) in each hemimandible. A transmucosal healing screw of 7 mm without oclusal contact was installed at the anterior implant as a model of non-submerged implant; in the posterior implant were installed a cover screw, using the submerged technique. After six weeks of healing, histomorphometric analysis of osseous tissue between the threads was performed. Was analyzed the implant unit as well as the cervical, meddle and apical region of implant. Student t test with 5 percent significance was used. The non-submerged implant model showed more bone formation than submerged implant without statistically significance (p=0.106); for regional analyses, cervical area shows more osseous formation than middle and apical areas. The regional analyses did not present statistical difference between areas for comparative analysis of submerged and non-submerged implant model. Non-submerged implant model it's not an obstacle for osseous formation.

El objetivo de esta investigación fue comparar la formación ósea alrededor de implantes dentales sumergidos y no sumergidos instalados en mandíbula de perro. Siete perros Beagle fueron utilizados en este protocolo; inicialmente fueron realizadas las exodoncias de dientes posteriores de mandíbula y luego de 3 meses de recuperación fueron instalados dos implantes dentales con tratamiento de superficie en cada hemimandíbula (substracción de titanio vía acidificación). En el implante anterior fue instalado también un conector transmucoso de 7 mm sin contacto oclusal y en el implante posterior fue instalado el tornillo de cierre. Luego de 6 semanas de recuperación, se realizó un análisis histomorfométrico del tejido óseo presente entre las roscas. Se analizó el implante como unidad así como también sus sectores cervical, medio y apical. Se utilizó la prueba estadística t de student con 5 por ciento de significancia estadística. El implante no sumergido presentó mayor formación ósea sin diferencias estadísticamente significativa (p=0.106); en los análisis regionales, el área cervical presentó mayor formación ósea que las áreas medianas y apicales. El análisis regional no presentó diferencias estadísticamente significativas entre ambos tipos de implante. El modelo de implante no sumergido no es un obstáculo para la formación ósea.

Bone histomorphometry: a concise review for endocrinologists and clinicians / Histomorfometria óssea: uma revisão concisa para endocrinologistas e clínicos

Bone histomorphometry is a quantitative histological examination of an undecalcified bone biopsy performed to obtain quantitative information on bone remodeling and structure. Labeling agents taken before the procedure deposit at sites of bone formation allowing a dynamic analysis. Biopsy is indicated to make the diagnosis of subclinical osteomalacia, to characterize the different forms of renal osteodystrophy and to elucidate cases of unexplained skeletal fragility. Bone histomorphometric parameters are divided into structural and remodeling subgroups, with the latter being subdivided into static and dynamic categories. Metabolic bone disorders such as osteomalacia, hyperparathyroidism, hypothyroidism, osteoporosis and renal osteodystrophy display different histomorphometric profiles. Antiresorptive and anabolic drugs used for the treatment of osteoporosis also induce characteristic changes in the bone biopsy. Bone histomorphometry is an important research tool in the field of bone metabolism and provides information that is not available by any other investigative approach.

Histomorfometria óssea é uma avaliação histológica quantitativa de uma biópsia óssea calcificada realizada para obter informação sobre a remodelação e a estrutura óssea. Uma análise dinâmica é possível quando substâncias que fazem a marcação do osso são tomadas antes do procedimento e se depositam no local de formação óssea. A biópsia é indicada para diagnóstico de osteomalácia, diferentes formas de osteodistrofia renal e nos casos não explicados de fragilidade esquelética. O preparo e a análise das amostras necessitam de um laboratório especializado. A histomorfometria avalia parâmetros estruturais e de remodelação óssea, sendo o último subdividido em estático e dinâmico. Doenças osteometabólicas como osteomalácia, hiperparatireoidismo, hipoparatireoidismo, osteoporose e osteodistrofia renal apresentam parâmetros histomorfométricos distintos. Medicações antirreabsortivas e anabólicas usadas no tratamento da osteoporose também induzem alterações características na biópsia óssea. A histomorfometria óssea é uma ferramenta importante no metabolismo ósseo e oferece informação que não é possível por nenhum outro método diagnóstico.

Hypoparathyroidism: clinical features, skeletal microstructure and parathyroid hormone replacement / Hipoparatiroidismo: aspectos clínicos, microestrutura esquelética e reposição do paratormônio

OBJECTIVE: Hypoparathyroidism is a disorder in which parathyroid hormone is deficient in the circulation due most often to immunological destruction of the parathyroids or to their surgical removal. The objective of this work was to define the abnormalities in skeletal microstructure as well as to establish the potential efficacy of PTH(1-84) replacement in this disorder. SUBJECTS AND METHODS: Standard histomorphometric and µCT analyses were performed on iliac crest bone biopsies obtained from patients with hypoparathyroidism. Participants were treated with PTH(1-84) for two years. RESULTS: Bone density was increased and skeletal features reflected the low turnover state with greater BV/TV, Tb. Wi and Ct. Wi as well as suppressed MS and BFR/BS as compared to controls. With PTH(1-84), bone turnover and bone mineral density increased in the lumbar spine. Requirements for calcium and vitamin D fell while serum and urinary calcium concentrations did not change. CONCLUSION: Abnormal microstructure of the skeleton in hypoparathyroidism reflects the absence of PTH. Replacement therapy with PTH has the potential to correct these abnormalities as well as to reduce the requirements for calcium and vitamin D.

OBJETIVO: O hipoparatiroidismo é uma doença em que há diminuição dos níveis circulantes do paratormônio, em geral, causada por destruição autoimune ou exerese cirúrgica. O objetivo deste estudo foi descrever as anormalidades microestrutrurais esqueléticas, como também o potencial terapêutico do uso do PTH(1-84). SUJEITOS E MÉTODOS: Histomorfometria padrão e análise de micro-CT foram realizadas em biópsias de crista ilíaca de indivíduos com hipoparatiroidismo. Os participantes foram tratados com PTH(1-84) por dois anos. RESULTADOS: A densidade óssea aumentou e os achados esqueléticos refletiram o estado de baixa remodelação óssea com maior BV/TV, Tb Wi e CT Wi, como também supressão de MS e BFR/BS quando comparado com o grupo controle. Com o uso de PTH(1-84), a remodelação óssea aumentou e a densidade óssea aumentou na coluna lombar. As necessidades de cálcio e vitamina D diminuíram e a calciúria não mudou. CONCLUSÃO: A microestrutura esquelética anormal no hipoparatiroidismo reflete a ausência do PTH. A terapia de reposição com PTH tem o potencial de reverter essas anormalidades, como também reduzir as necessidades de cálcio e vitamina D.

Efecto de la terapia láser de baja potencia sobre el hueso alveolar dañado / The low level laser therapy effect on alveolar bone damaged

La terapia con láser de baja potencia ha demostrado tener propiedades analgésicas antiinflamatorias, bioestimulantes y promotoras de la respuesta tisular al daño. El propósito de este estudio fue determinar el efecto que el láser de baja potencia tiene sobre el hueso alveolar dañado. Se utilizaros 13 ratas Sprage Dawley, en las cuales se realizó una lesión estandarizada del hueso alveolar, posterior a lo cual una muestra aleatoria de 7 ratas fue sometida a un protocolo de irradiación de 6 J/cm2, tres veces por semana durante cuatro semanas. Las muestras obtenidas del sitio lesionado en ratas expuestas y no expuestas a la terapia fueron procesadas para hematoxilina eosina, contabilizándose el número de osteonas al microscopio óptico con aumento de 40x. Los resultados muestran un aumento en el número de osteonas en el grupo irradiado, diferencia que resultó estadísticamente significativa (p<0,01), con una alta fuerza de asociación estadística (O.R=5,6 ). Estos resultados sugieren que la terapia láser de baja potencia favorece la respuesta del hueso alveolar dañado.

The Low Level Laser Therapy (LLLT) has demostrated to have analgesic, antiinflamatory, bioestimulant and promoters from the tissues responses properties to the damage. The purpose of this study was determinate the Low Level Laser Therapy effect in the damaged alveolar bone. Thirteen Sprage Dawley rats were used. Total number of animals alveolar bones a standarized lesion was made, later an aleatory sample of seven rats was subjected to the irradiation protocol 6 J/cm², three times per week during four weeks. The obtained samples of the injured area, of exposed and not exposed rats to the laser therapy were processed for hematoxilin & eosin, being the osteon number count by optic microscope with increase of 40x. The result show an increase in the osteon number in the irradiated group, this differentiated was statistically significant (p<0.01), whit a high strength of statistical association (OR=5.6). These result suggest that the therapy laser of low power favors the answer of the damaged alveolar bone.

Effects of fibrin sealer and resorbable gelatin on the repair of osseous defects in rat tibia

Gelfoam® - a biologically resorbable gelatin sponge - has the function of restricting hemorrhage, providing platelet rupture, and supporting fibrin threads. Beriplast® - a fibrinogen-thrombin compound - is used to adhere tissues, to consolidate sutures and in hemostasis. The objective of this study was to perform a histological analysis of the effects of haemostatic agents on osseous repair. These materials were inserted into surgical sites in young rat right and left tibiae. After the observation periods of 7, 14, 30 and 45 days, according to the bioethic protocol, the animals were killed, the tibiae were removed and fixed in 10 percent formalin and decalcified in equal parts of formic acid and sodium citrate solutions. After routine processing, the specimens were embedded in paraffin for microtomy. Analysis of the results demonstrated that the haemostatic agents are effective in controlling hemorrhage; they stimulate osteogenesis, featuring a pattern of osseous tissue formation similar to the control pattern, although the amount of osseous trabeculae was superior, especially in the Gelfoam group in the periods of 7 and 14 days; 30 days after surgery, the delay in tissue healing in the control group in relation to the experimental groups started to decrease, and the control and experimental groups exhibited similar tissue repair after 45 days, when all the groups exhibited secondary osseous tissue.

Gelfoam® - uma esponja de gelatina biologicamente reabsorvível - tem por função coibir as hemorragias, promover o rompimento de plaquetas e sustentar a rede de fibrina. Beriplast P® - um composto de fibrinogênio-trombina - é usado na adesão de tecidos, consolidação de suturas e hemostasia. O objetivo deste estudo foi verificar histologicamente os efeitos de agentes hemostáticos na reparação óssea, os quais foram colocados em lojas cirúrgicas nas tíbias direita e esquerda de ratos jovens. Após os períodos de observação de 7, 14, 30 e 45 dias, segundo o protocolo bioético, os animais foram sacrificados, as tíbias foram removidas e fixadas em formalina a 10 por cento e descalcificadas em partes iguais de soluções de ácido fórmico e citrato de sódio, para inclusão em parafina e microtomia. A análise dos resultados demonstrou que os agentes hemostáticos têm eficácia no controle hemorrágico; eles estimulam a osteogênese, provocando um padrão de formação de tecido ósseo semelhante ao padrão do grupo controle, embora a quantidade de trabéculas ósseas tenha sido superior principalmente no grupo do Gelfoam, nos períodos de 7 e 14 dias; após os 30 dias da cirurgia, o retardo na reparação tecidual do grupo controle em relação aos grupos experimentais começou a decrescer, tornando-se a reparação tecidual daquele semelhante à destes aos 45 dias, quando todos os grupos apresentaram tecido ósseo secundário.

Morphological and chemical analysis of bone substitutes by scanning electron microscopy and microanalysis by spectroscopy of dispersion energy

This study evaluated the morphological and chemical composition of the following bone substitutes: cancellous and cortical organic bovine bone with macro and microparticle size ranging from 1.0 to 2.0 mm and 0.25 to 1.0 mm, respectively; inorganic bovine bone with particle size ranging from 0.25 to 1.0 mm; hydroxyapatite with particle size ranging from 0.75 to 1.0 mm; and demineralized freeze-dried bone allograft with particle size ranging from 0.25 to 0.5 mm. The samples were sputter-coated with gold in an ion coater, the morphology was observed and particle size was measured under vacuum by scanning electron microscopy (SEM). The chemical composition was evaluated by spectroscopy of dispersion energy (EDS) microanalysis using samples without coating. SEM analysis provided visual evidence that all examined materials have irregular shape and particle sizes larger than those informed by the manufacturer. EDS microanalysis detected the presence of sodium, calcium and phosphorus that are usual elements of the bone tissue. However, mineral elements were detected in all analyzed particles of organic bovine bone except for macro cancellous organic bovine bone. These results suggest that the examined organic bovine bone cannot be considered as a pure organic material.

Neste estudo foram avaliados a morfologia, o tamanho e a composição química dos seguintes substitutos ósseos: osso bovino orgânico cortical e esponjoso com micropartículas medindo entre 0,25 e 1,0 mm e macropartículas 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 tamanho das partículas, as amostras foram preparadas em porta-espécime, metalizadas em ouro e analisadas a vácuo em microscopia eletrônico de varredura (MEV). Para a análise da composição química, as partículas não foram metalizadas e foram analisadas por microanálise por espectroscopia por dispersão de energia (EDS). A análise em MEV, demonstrou que as partículas substitutos ossos apresentaram formato irregular e tamanho variável, maior do que o mencionado pelo fabricante. A microanálise por 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, exceto para a macropartícula de osso bovino orgânico esponjoso. Esses resultados sugerem que o osso bovino orgânico não pode ser considerado um material orgânico puro.

Microwave-induced fast decalcification of rat bone for electron microscopic analysis: an ultrastructural and cytochemical study

Bone decalcification is a time-consuming process. It takes weeks and preservation of the tissue structure depends on the quality and velocity of the demineralization process. In the present study, a decalcification methodology was adapted using microwaving to accelerate the decalcification of rat bone for electron microscopic analysis. The ultrastructure of the bone decalcified by microwave energy was observed. Wistar rats were perfused with paraformaldehyde and maxillary segments were removed and fixed in glutaraldehyde. Half of specimens were decalcified by conventional treatment with immersion in Warshawsky solution at 4ºC during 45 days, and the other half of specimens were placed into the beaker with 20 mL of the Warshawsky solution in ice bath and thereafter submitted to irradiation in a domestic microwave oven (700 maximum power) during 20 s/350 W/±37ºC. In the first day, the specimens were irradiated 9 times and stored at 40ºC overnight. In the second day, the specimens were irradiated 20 times changing the solution and the ice after each bath. After decalcification, some specimens were postfixed in osmium tetroxide and others in osmium tetroxide and potassium pyroantimonate. The specimens were observed under transmission electron microscopy. The results showed an increase in the decalcification rate in the specimens activated by microwaving and a reduction of total experiment time from 45 days in the conventional method to 48 hours in the microwave-aided method.

A preservação da estrutura de ossos é dependente da qualidade e da velocidade em que ocorre o processo de desmineralização. Neste estudo foi observada a ultraestrutura de maxila de rato descalcificada utilizando microondas. Ratos Wistar sofreram perfusão com paraformaldeído e o segmento de maxila retirado e fixado em glutaraldeído. Após esta etapa algumas amostras foram descalcificadas por imersão em solução de Warshawsky durante 45 dias a 4(0)C. Outras amostras foram submetidas a irradiação por microondas (forno de microondas doméstico 700 Watts de potência), durante 20 s/350 W/ ± 37ºC. No primeiro dia foram realizadas um total de 9 irradiações e os espécimes foram deixadas posteriormente a 4ºC por 12 h na solução descalcificadora sem agitação. No segundo dia, os fragmentos foram submetidos à nova irradiação totalizando 20 banhos, trocando-se a solução e o gelo a cada banho. A seguir algumas amostras foram pós-fixadas com tetróxido de ósmio e outras com tetróxido de ósmio e piroantimonato de potássio. As amostras foram observadas em microscópio eletrônico de transmissão. Os resultados mostraram que o processo de descalcificação ativado por microondas reduziu para 48 h o período de descalcificação, o qual pelo método tradicional ocorre em 45 dias.

Effect of water soluble soybean fiber [WSSF] on bone changes induced by ovariectomy in female albino rat. a light and scanning electron microscopic study

Ovarian hormone deficiency impairs Ca absorption and decreases bone mineral density. Osteoporosis and other modern diseases like cancer and coronary heart disease are thought to be associated with consumption of westernized food that is deficient in fiber. Soybean and soybean products are popular foods in Japan. The lower incidence of osteoporosis in Japanese women is attributed to the high intake of soybean products. Thirty five adult female albino rats were used in the current study to evaluate the role of water soluble soybean fiber [WSSF] in amelioration of bone changes that might result from ovariectomy [artificial menopause]. Animals were divided into 3 groups. Group I, served as a control group. Group II, comprised the Sham operated rats. Group III, was firmed of ovariectomized rats, and was further divided into 2 subgroups. Subgroup IIIa, comprised the ovariectomized rats that received ordinary standard diet. Subgroup IIIb, was composed of ovariectomized rats that received diet supplemented with WSSE. Ovariectomy in the present study resulted in a statistically highly significant reduction in the mean cortical and trabecular bone thickness. The periosteum shoved decreased cellularity. The mean number of osteoclasts was increased per high power field. Cortical bone demomostated few Haversian canals amid there was osteolysis in the core of bone trabeculae. The mean serum levels of osteocalcin and alkaline phosphatase enzyme were decreased. Diet enriched with WSSF ameliorated the structural and biochemical osteoporotic changes induced by ovariectomy. Dietary consumption of' WSSF was very effective in ameliorating the bone mineral loss that resulted from ovariectomy. So, it is recommended that WSSF is advised to be added to the diet in order to achieve a satisfactory bone quality after menopause

Assessment of bovine biomaterials containing bone morphogenetic proteins bound to absorbable hydroxyapatite in rabbit segmental bone defects

PURPOSE: To evaluate the osteo-regenerative capacity of two proprietary bone grafting materials, using a segmental defect model in both radial diaphyses of rabbits. METHODS: The right defect was filled with pooled bone morphogenetic proteins (pBMPs) bound to absorbable ultrathin powdered hydroxyapatite (HA) mixed with inorganic and demineralized bone matrix and bone-derived collagen, derived from bovine bone (Group A). The left defect was filled with bovine demineralized bone matrix and pBMPs bound to absorbable ultrathin powdered HA (Group B). In both groups, an absorbable membrane of demineralized bovine cortical was used to retain the biomaterials in the bone defects, and to guide the tissue regeneration. The rabbits were euthanized 30, 90 and 150 days after surgery. Radiographic, tomographic and histologic evaluations were carried out on all specimens. RESULTS: At 30 days, the demineralized cortical bone cover was totally resorbed in both groups. HA was totally resorbed from Group A defects, whereas HA persisted in Group B defects. A prominent foreign body reaction was evident with both products, more pronounced in sections from Group B. At 90 days, the defects in Group B exhibited more new bone than Group A. However, at 150 days after surgery, neither treatment had stimulated complete repair of the defect. CONCLUSION: The partial bone healing of the segmental defect occurred with low or none performance of the biomaterials tested.

OBJETIVO: Avaliar a capacidade osteo-regenerativa de dois biomateriais utilizando um modelo de defeito segmentar efetuado nas diáfises do rádio de coelhos. MÉTODOS: O defeito direito foi preenchido com pool de proteínas morfogenéticas ósseas (pBMPs) e hidroxiapatita em pó ultrafina absorvível (HA) combinada com matriz óssea inorgânica desmineralizada e colágeno, derivados do osso bovino (Grupo A). O defeito esquerdo foi preenchido com matriz óssea desmineralizada bovina com pBMPs e hidroxiapatita em pó ultrafina absorvível (Grupo B). Em ambos os defeitos utilizou-se membrana reabsorvível de cortical bovina desmineralizada para reter os biomateriais no defeito ósseo e guiar a regeneração tecidual. Os coelhos foram submetidos à eutanásia aos 30, 90 e 150 dias após a cirurgia. Foram efetuados exames radiográficos, tomográficos e histológicos em todos os espécimes. RESULTADOS: Aos 30 dias de pós-cirúrgico, o osso cortical desmineralizado foi totalmente reabsorvido em ambos os grupos. A HA tinha reabsorvido nos defeitos do Grupo A, mas persistiu nos do Grupo B. Uma reação de corpo estranho foi evidente com ambos os produtos, porém mais pronunciada no Grupo B. Aos 90 dias os defeitos do grupo B tinham mais formação óssea que os do Grupo A. Entretanto, aos 150 dias após a cirurgia, nenhum tratamento havia promovido o completo reparo do defeito. CONCLUSÃO: Os biomateriais testados contribuíram pouco ou quase nada para a reconstituição do defeito segmentar.

Morphogenetic protein rhBMP-2 and new bone formation / Proteína Morfogenética rhBMP-2 y Tejido Ósteoneoformado

Esta revisión de la literatura tiene como objetvo mostrar las principales características morfogenéticas, de la proteína rhBMP-2, de mayor prpiedad osteoinductiva, estudiados desde su descubrimiento hasta la actualidad, señalando las diferentes utilizaciones y aplicaciones de esta proteína.

This work aim to show by literature review the principal characteristics of morphogenetic proteins, in special of the rhBMP-2, with the major osteoinductive properties, presented in the prime works count from it discovery until actually, showing the most varieties and applications of this protein.

Comparation on Haversian system between human and animal bones by imaging analysis / 法医学杂志

OBJECTIVE@#To explore the differences in Haversian system between human and animal bones through imaging analysis and morphology description.@*METHODS@#Thirty-five slices grinding from human being as well as dog, pig, cow and sheep bones were observed to compare their structure, then were analysed with the researchful microscope.@*RESULTS@#Plexiform bone or oeston band was not found in human bones; There were significant differences in the shape, size, location, density of Haversian system, between human and animal bones. The amount of Haversian lamella and diameter of central canal in human were the biggest; Significant differences in the central canal diameter and total area percentage between human and animal bones were shown by imaging analysis.@*CONCLUSION@#(1) Plexiform bone and osteon band could be the exclusive index in human bone; (2) There were significant differences in the structure of Haversian system between human and animal bones; (3) The percentage of central canals total area was valuable in species identification through imaging analysis.

Influência da ovariectomia na movimentaçäo dentária induzida: avaliaçäo microscópica / Influence of the ovariectomy in the induced tooth movement: microscopic evaluation

A ovariectomia promove uma depleçäo na síntese de estrogênio, um hormônio com efeitos sobre o metabolismo ósseo. Com o presente trabalho propôs-se analisar os efeitos desta condiçäo nos tecidos dentários e ósseos envolvidos na movimentaçäo dentária induzida. Foram utilizadas ratas com e sem ovariectomia, que tiveram seus primeiros molares superiores movimentados durante 24 horas, três e cinco dias. A análise por microscopia óptica revelou a näo interferência da depleçäo de estrogênio nos tecidos dentários duros, näo sendo detectadas reabsorçöes dentárias. No tecido ósseo, contatou-se um moderado aumento dos aspectos reabsorvitivos nos animais ovariectomizados em relaçäo aos animais näo ovariectomizados. O presente trabalho mostrou diferenças entre as áreas ósseas inter-radiculares e externas quanto à susceptibilidade à reabsorçäo durante a moviemntaçäo dentária, com as áreas inter-radiculares apresentando aspectos mais proeminentes de reabsorçäo óssea, independente da condiçäo de ovariectomia