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Bone Histology (bone + histology)
Selected AbstractsLYSTROSAURUS MURRAYI (THERAPSIDA, DICYNODONTIA): BONE HISTOLOGY, GROWTH AND LIFESTYLE ADAPTATIONSPALAEONTOLOGY, Issue 6 2005SANGHAMITRA RAY Abstract:, Examination of the bone microstructure of Lystrosaurus murrayi from India and South Africa reveals a predominance of fibrolamellar bone tissue, which suggests rapid periosteal osteogenesis and an overall fast growth. Four distinct ontogenetic stages have been identified based on tissue type, organization of the primary osteons, incidence of growth rings, secondary reconstruction and endosteal bone deposition. An indeterminate growth strategy is proposed for Lystrosaurus. Inter-elemental histovariability suggests differential growth rate of the skeletal elements within the same individual, and among different individuals. The high cortical thickness of the dorsal ribs, an extensive secondary reconstruction in the cortical region of different skeletal elements that resulted in erosionally enlarged channels from the perimedullary to the midcortical region, and trabecular infilling of the medullary region even in the diaphyseal sections of the limb bones suggest at least a semi-aquatic lifestyle for L. murrayi. [source] The bone histology of osteoderms in temnospondyl amphibians and in the chroniosuchian BystrowiellaACTA ZOOLOGICA, Issue 1 2010Florian Witzmann Abstract Witzmann, F. and Soler-Gijón, R. 2010. The bone histology of osteoderms in temnospondyl amphibians and in the chroniosuchian Bystrowiella. ,Acta Zoologica (Stockholm) 91: 96,114 Bone histology of osteoderms in the armoured temnospondyl Peltobatrachus, plagiosaurids (Gerrothorax, Plagiosuchus) and dissorophids (Aspidosaurus, Cacops, Platyhystrix), as well as in the chroniosuchian Bystrowiella, is studied. The massive osteoderms of Peltobatrachus and Gerrothorax consist of homogeneous parallel-fibred bone, whereas in dissorophids, a lightly built, trabecular middle region is mantled by a thin cortex that is composed of a plywood-type structure. In Bystrowiella and Plagiosuchus, the osteoderms consist to a large degree of interwoven primary fibres and have cell lacunae that bear stumpy canaliculi. The differences in the histological structure of dissorophids and plagiosaurids suggest an iterative evolution of osteoderms. Furthermore, histology in Plagiosuchus indicates a metaplastic development of the osteoderms, whereas the osteoderms of Gerrothorax represent periosteal ossifications as in dissorophids. This suggests a convergent origin of osteoderms also within plagiosaurids. The extensive armour in Gerrothorax probably constituted a calcium reservoir, indicated by cyclical resorption events preserved in the external cortex and interpreted as a physiological response to periodic changes in salinity of the aquatic environment. In contrast, the unique osteoderm structure of dissorophids provides maximum stability and minimum bone mass, and is coherent with the interpretation that the osteoderms served to strengthen the vertebral column during terrestrial locomotion. [source] Bone histology of Silesaurus opolensisDzik, 2003 from the Late Triassic of PolandLETHAIA, Issue 2 2010UCJA FOSTOWICZ-FRELIK Fostowicz-Frelik, ,. & Sulej, T. 2009: Bone histology of Silesaurus opolensisDzik, 2003 from the Late Triassic of Poland. Lethaia, Vol. 43, pp. 137,148. The phylogenetic relationships of Silesaurus opolensis have been the subject of intense debate since its discovery. Silesaurus possesses some features characteristic of ornithischian dinosaurs, such as the presence of a beak at the front of the lower jaw, yet it lacks a number of important femoral and dental synapomorphies of Dinosauria. The microstructure of the long bones (femur, tibia and metatarsal) and ribs of this species reveals a relatively intensive rate of growth, comparable with that seen in small dinosaurs and the gracile crocodylomorph Terrestrisuchus. Cortical bone formed mainly by periosteal tissue with fibro-lamellar matrix (in older specimens parallel fibred) shows very little secondary remodelling and only in one specimen (large tibia ZPAL Ab III/1885) few lines of arrested growth are present in the outermost cortex. The vascularization is relatively dense, mainly longitudinal and ceases towards the periphery, forming almost avascular parallel fibred bone at the bone surface. This indicates maturation and significant decrease in the growth ratio in mature specimens of S. opolensis. The delicate trabeculae exhibit cores formed by the primary cancellous tissue lined with lamellar endosteal bone. The rather intense growth of S. opolensis implies a relatively high metabolic rate. Moreover, evidence from the fibro-lamellar tissue, predominant in the cortex, suggests that this kind of rapid bone deposition could be more typical of Archosauria than previously assumed, a prerequisite for the evolution of the very fast growth rates observed in large ornithischians, sauropods and large theropods. ,Archosauria, Bone histology, Dinosauriformes, Late Triassic, Silesaurus opolensis. [source] Fate of monocortical bone blocks grafted in the human maxilla: a histological and histomorphometric studyCLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2003Ilara R. Zerbo Abstract: Local bone defects in the anterior maxilla are commonly grafted with monocortical blocks of autologous bone in order to restore the defect site prior to the placement of dental implants. Increasing evidence suggests that osteocytes are involved in the control of bone remodelling and thus may be important for optimalisation of bone structure around implants, and thus for implant osseointegration. However, it is not well known whether osteocytes will survive when bone blocks are grafted into defects. We grafted 19 patients with monocortical bone blocks derived from the symphysis, to the defect site in the maxillary alveolar process. The bone grafts were left to heal for times varying from 2.5 to 7 months. During implant installation, bone biopsies were removed using a trephine burr, and processed for hard tissue histology. Bone histology and histomorphometry were then carried out in order to gain insight into the density, viability and remodelling of the graft. Clinically, all the bone grafts were successful, with no implant failures, and little resorption was seen. Histologically, bone volume expressed as percentage of tissue volume at the implant site varied from 27% to 57% with an overall average of 41%. Bone fields with empty osteocyte lacunae were observed and measured. The amount of this so-called nonvital bone (NVB) varied between 1% and 34% of the total tissue volume. The amount of NVB decreased significantly with the time of healing. The data suggest that the majority of the osteocytes of the monocortical bone do not survive grafting. The results indicate that the NVB is progressively remodelled into new vital bone 7 months after grafting. Résumé Les lésions osseuses locales dans le maxillaire antérieur sont souvent greffées avec des blocs monocorticaux d'os autogène afin de restaurer le site avant le placement d'implants. Il semble de plus en plus évident que les ostéocytes sont induits dans le contrôle du remodelage osseux et pourraient donc être importants pour optimiser la structure osseuse autour des implants et donc l'ostéoïntégration implantaire. Cependant le taux de survie des ostéocytes lorsque les blocs osseux sont greffés dans les lésions n'est pas suffisament connu. Dix-neuf patients ont été greffés avec des blocs osseux monocorticaux provenant de la symphyse dans le site de la lésion au niveau des alvéoles maxillaires. Les greffons osseux sont restés in situ durant des périodes de 2,5 à 7 mois. Pendant l'insertion des implants des biopsies osseuses ont été prélevées avec un trépan et analysées par histologie. L'histologie osseuse et l'histomorphométrie ont été effectuées afin d'analyser la densité, la viabilité et le remodelage osseux. Cliniquement tous les greffons osseux ont été effectués avec succès sans aucun échec implantaire et peu de résorption. Histologiquement, le volume osseux exprimé en tant que pourcentage du volume tissulaire au site implantaire variait de 27 à 57 % avec une moyenne totale de 41 %. Les champs osseux avec une lacune d'ostéocytes vides ont été observés et mesurés. La quantité d'os non-vivant variait de 1 à 34 % du volume tissulaire total. La quantité d'os non-vivant diminuait significativement avec le temps de guérison. Ces données suggèrent que la majorité des ostéocytes de l'os monocortical ne survivent pas au greffage. Les résultats indiquent que l'os non-vivant est progressivement remodelé en nouvel os vivant en sept mois après le greffage. Zusammenfassung Das Schicksal von monokortikalen Knochenblöcken, welche in die menschliche Maxilla transplantiert werden: eine histologische und histomorphometrische Studie Lokale Knochendefekte in der anterioren Maxilla werden normalerweise mit monokortikalen Blöcken aus autologem Knochen aufgebaut, um den Defekt vor der Eingliederung von dentalen Implantaten aufzufüllen. Aufgrund zunehmender Evidenz wird vermutet, dass Osteozyten an der Kontrolle der Knochenremodellierung beteiligt und daher wichtig für die Optimierung der Knochenstrukturen um Implantate und für die Osseointegration der Implantate sind. Es ist jedoch nicht ausreichend bekannt, ob Osteozyten überleben, wenn Knochenblöcke in Defekte transplantiert werden. Bei 19 Patienten wurden monokortikale Knochenblöcke von der Symphyse in den Defektbereich des Alveolarfortsatzes im Oberkiefer transplantiert. Die Knochentransplantate heilten in einer Zeit zwischen 2.5 und 7 Monaten ein. Während der Implantation wurden mit einer Hohlfräse Knochenbiopsien entnommen und für die Hartgewebshistologie aufgearbeitet. Der Knochen wurde histologisch und histomorphometrisch untersucht, um Einsicht in die Dichte, Vitalität und Remodellierung des Transplantats zu erlangen. Klinisch waren alle Knochentransplantate erfolgreich eingeheilt. Es konnten keine Implantatmisserfolge gesehen werden und es traten nur geringe Resorptionen auf. Histologisch variierte das Knochenvolumen, ausgedrückt als Prozentsatz Gewebevolumen an der Implantatstelle, von 27% bis 57% mit einem Durchschnitt von 41%. Knochenfelder mit leeren Osteozytenlakunen konnten beobachtet und ausgemessen werden. Die Menge dieses sogenannten nicht-vitalen Knochens variierte zwischen 1% und 34% des totalen Gewebevolumens. Die Menge des nicht-vitalen Knochens nahm signifikant mit der Länge der Einheilzeit ab. Die Daten lassen vermuten, dass die Mehrzahl der Osteozyten des monokortikalen Knochens die Transplantation nicht überleben. Die Resultate zeigen, dass der nicht-vitale Knochen innert 7 Monaten nach der Transplantation progressiv in neuen vitalen Knochen umgebaut wird. Resumen Los defectos óseos locales en el maxilar anterior se injertan comúnmente con bloques monocorticales de hueso autólogo en orden a restaurar el lugar del defecto antes de la colocación de implantes dentales. Una creciente evidencia sugiere que los osteocitos están involucrados en el control del remodelado óseo y de este modo ser importantes para la optimalización de la estructura ósea alrededor de los implantes y así para la osteointegración de los implantes. Sin embargo, no se conoce bien si los osteocitos sobrevivirán cuando los bloques óseos sean injertados en los defectos. Hemos injertado a 19 pacientes con bloques de hueso monocortical derivados de la sínfisis al lugar del defecto en el proceso alveolar maxilar. Los injertos óseos se dejaron cicatrizar por un periodo de tiempo que varió entre 2.5 a 7 meses. Durante la implantación se tomaron biopsias óseas usando una fresa de trépano y se procesaron para histología de tejidos duros. Se llevaron a cabo entonces histología ósea e histomorfometría en orden a hacerse una idea acerca de la densidad, viabilidad y remodelado del injerto. Clínicamente, todos los injertos óseos tuvieron éxito sin fracasos de implantes y se observó poca reabsorción ósea. Histológicamente, el volumen óseo expresado como porcentaje de volumen tisular en el lugar del implante varió del 27% al 57% con una media general del 41%. Se observaron y midieron campos óseos con lagunas óseas vacías. La cantidad de hueso no vital disminuyó significativamente durante el tiempo de cicatrización. [source] Development of renal bone diseaseEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 2006A. Ferreira Abstract Renal osteodystrophy (ROD) develops as the early stages of chronic renal failure (CRF) and covers a spectrum of bone changes observed in the uraemic patient, which extend from high remodelling bone disease (frequently known as osteitis fibrosa) to low turnover, or adynamic disease. Between these two extremes there are also cases of bone mineralization compromised in variable degrees, as is the case of ,mixed bone disease' and osteomalacia. The dynamic process of bone remodelling is compromised in CRF, and a positive or negative bone balance can be observed in uraemic patients. In addition to the classic modulators of bone remodelling, like parathyroid hormone, calcitriol and calcitonin, other factors were recently identified as significant modulators of osteoblast and osteoclast activation in uraemic patients. In fact, different cytokines and growth factors, acting at an autocrine or paracrine level, seem to play a relevant role in the bone and mineral changes observed in uraemia. Recently, observations have been made of the development of more sensitive and specific techniques to assay different biochemical markers of bone turnover and mineral metabolism. Analogously, new contributions of conventional bone histology, bone immunocytochemistry and molecular biology, which enabled the understanding of some etiopathogenic mechanisms of ROD, were observed. [source] Treatment of Idiopathic Hyperphosphatasia With Intensive Bisphosphonate TherapyJOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2004Tim Cundy MD Abstract In a family with IH, a rare high turnover bone disease, two older siblings were wheelchair-bound with severe skeletal deformity by age 15. Their youngest affected sibling was treated intensively with intravenous bisphosphonates for 3 years. The treatment was well tolerated and prevented the development of deformity and disability. Introduction: Idiopathic hyperphosphatasia (IH, also known as juvenile Paget's disease) is a rare genetic bone disease characterized by very high bone turnover and progressive bony deformity. Inhibitors of bone resorption have been used to suppress bone turnover in the short term, but there is no published data on long-term efficacy. Materials and Methods: An 11-year-old girl with IH, who had two severely affected older siblings, presented with progressive deformity and deafness and long bone fractures. Conventional pediatric doses of pamidronate had failed to prevent clinical deterioration or suppress bone turnover completely. Intensive bisphosphonate therapy (frequent 5-mg ibandronate infusions) was given to try and arrest progression of the skeletal disease. Growth and development, pure tone audiometry, biochemistry, radiology, densitometry (DXA), and bone histology were monitored. Results: A total of 45 mg ibandronate was given over 3 years until skeletal maturity was reached (20, 15, and 10 mg for years 1,3, respectively). Ibandronate treatment was well tolerated, and biochemical markers of bone turnover suppressed to within the age-appropriate normal range There was some progression of her thoracic kyphosis, but she had no further fractures and remained mobile and active at an age when her siblings had become wheelchair-bound. A significant recovery of hearing (p < 0.01) was documented, particularly at low frequencies. Radiographs showed improvement in spinal osteoporosis and cortical bone dimensions and arrest of progressive acetabular protrusion. Areal bone density increased substantially (lumbar spine z-score from ,2.2 to + 1.8). Tetracycline-labeled bone biopsy specimens were taken before and after 18 months of intensive treatment. The second biopsy showed suppression of bone turnover and a doubling of trabecular thickness, with no mineralization defect, and no osteopetrosis. Conclusions: Intensive bisphosphonate treatment prevented the development of deformity and disability and improved hearing in this child with IH. The dose of bisphosphonate, which is substantially greater than is usually used in pediatric bone disease, had no adverse effects, in particular on bone mineralization. [source] | |||||||||||||