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Tibia
Kinds of Tibia Terms modified by Tibia Selected AbstractsPostpubertal Architectural Developmental Patterns Differ Between the L3 Vertebra and Proximal Tibia in Three Inbred Strains of Mice,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 12 2008Helen R Buie Abstract An understanding of normal microarchitectural bone development patterns of common murine models is needed. Longitudinal, structural, and mineralization trends were evaluated by in vivo ,CT over 12 time points from 6,48 wk of age at the vertebra and tibia of C3H/HeN, C57BL/6, and BALB/C mice. Longitudinal growth occurred rapidly until 8,10 wk, slowed as the growth plate bridged, and fused at 8,10 mo. Structural augmentation occurred through formation of trabeculae at the growth plate and thickening of existing ones. In the vertebrae, BV/TV increased rapidly until 12 wk in all strains. Between 12 and 32 wk, the architecture was stable with BV/TV deviating <1.1%, 1.6%, and 3.4% for the C57BL/6, BALB/C, and C3H/HeN mice. In contrast, the tibial architecture changed continuously but more moderately for BV/TV and TbTh compared with the vertebra and with comparable or larger changes for TbN and TbSp. Age-related trabecular deterioration (decreased BV/TV and TbN; increased TbSp and structure model index) was evident at both sites at 32 wk. In all strains, the cortex continued to develop after trabecular values peaked. The temporal plateau of BMD was variable across mouse strains and site, whereas tissue mineral density was attained at ,6 mo for all sites and strains. Geometric changes at the tibial diaphysis occurred rapidly until 8,10 wk, providing the C57BL/6 mice and C3H/HeN mice with the highest torsional and compressive rigidity, respectively. In summary, key skeletal development milestones were identified, and architectural topology at the vertebra was found to be more stable than at the tibia. [source] Regional Alterations of Type I Collagen in Rat Tibia Induced by Skeletal Unloading,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2002Masashi Shiiba Abstract Skeletal unloading induces loss of mineral density in weight-bearing bones that leads to inferior bone mechanical strength. This appears to be caused by a failure of bone formation; however, its mechanisms still are not well understood. The objective of this study was to characterize collagen, the predominant matrix protein in bone, in various regions of tibia of rats that were subjected to skeletal unloading by 4 weeks tail suspension. Sixteen male Sprague-Dawley rats (4 months old) were divided into tail suspension and ambulatory controls (eight rats each). After the tail suspension, tibias from each animal were collected and divided into five regions and collagen was analyzed. The collagen cross-linking and the extent of lysine (Lys) hydroxylation in unloaded bones were significantly altered in proximal epiphysis, diaphysis, and, in particular, proximal metaphysis but not in distal regions. The pool of immature/nonmineralized collagen measured by its extractability with a chaotropic solvent was significantly increased in proximal metaphysis. These results suggest that skeletal unloading induced an accumulation of post-translationally altered nonmineralized collagen and that these changes are bone region specific. These alterations might be caused by impaired osteoblastic function/differentiation resulting in a mineralization defect. [source] Development of Galanin-Containing Nerve Fibres in Rat TibiaANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2009M. Gajda Summary Galanin exerts tonic inhibition of nociceptive input to the central nervous system. Recently, this peptide was demonstrated in several neuronal and non-neuronal structures in bones and joints. In this study, the time of appearance and topographic localization of galanin-containing nerve fibres in bone were studied in rats from gestational day 16 (GD16) to postnatal day 21 (PD21). The tibia was chosen as a model of developing long bone and indirect immunofluorescence combined with confocal laser scanning microscopy was used to identify galanin-immunoreactive (GAL-IR) nerve fibres. The earliest, sparse GAL-IR fibres were observed on GD21 in the perichondrium of both epiphyses and in the periosteum of the diaphysis. From PD1 onwards, GAL-IR fibres were also seen in the bone marrow cavity and in the region of the inter-condylar eminence of the knee joint. Intramedullary GAL-IR fibres in proximal and distal metaphyses appeared around PD1. Some of them accompanied blood vessels, although free fibres were also seen. GAL-IR fibres located in the cartilage canals of both epiphyses were observed from PD7, in the secondary ossification centres from PD10 and in the bone marrow of both epiphyses from PD14. The time course and localization of galanin-containing nerve fibres resemble the development of substance P- and CGRP-expressing nerve fibres, thus suggesting their sensory origin. [source] The impact of nicotine on bone healing and osseointegrationCLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2005An experimental study in rabbits Abstract Objectives: To examine the short-term effect of nicotine on bone healing and osseointegration. Material and methods: Sixteen female rabbits were divided into two groups. The test group was exposed to nicotine tartrate for 8 weeks and the control group was exposed to placebo. Nicotine or placebo was administered via a miniosmotic pump and plasma cotinine levels were measured weekly. The pump delivered 15 mg of nicotine/day for the animals in the test group. All rabbits had three tibial bone preparations. In the proximal and distal bone bed, implants were placed after 4 weeks (right tibia) and after 6 weeks (left tibia). Thus, 2- and 4-week healing groups were created. Removal torque test (RMT) was performed at the distal implants. Ground sections were made from the proximal and the central bone beds. The fraction of mineralized bone in contact to the implant (BIC) and the bone density within the implant threads (BD-i) were determined for the bone,implant specimens. For the central bone beds without implants the bone density (BD-c) in the bone defects was determined. Results: No significant difference in RMT values was found between the test and the control group. Histomorphometric measurements of the BIC and the peri-implant BD-i showed no significant differences between the test and the control group after 2 or 4 weeks. Significant differences were, however, found between the 2- and 4-week samples. In the central bone beds, there was no significant difference in BD-c between the test and the control group. Conclusion: Nicotine exposure in a short period of time did not have a significant impact on bone healing or implant osseointegration in rabbits. Résumé Le but de l'étude a été d'examiner l'effet à court terme de la nicotine sur la guérison osseuse et l'ostéoïntégration. Seize lapines ont été réparties en deux groupes. Le groupe test était exposé au tartrate de nicotine durant huit semaines et le groupe contrôle était exposé au placebo. La nicotine et le placebo étaient administrés par une pompe miniosmotique et les teneurs de cotinine plasmatique étaient mesurées chaque semaine. La pompe distillait 15 mg de nicotine par jour pour les animaux du groupe test. Toutes les lapines avaient trois préparations osseuses. Dans le lit osseux proximal et distal, les implants étaient placés après quatre semaines (tibia droit) et six semaines (tibia gauche) Des groupes de guérison de deux et de quatre semaines ont ainsi été créés. Des tests de torsion à l'enlèvement ont été effectués au niveau des implants distaux. Des coupes ont été effectuées pour les lits osseux centraux et proximaux. La fraction d'os minéralisé en contact avec l'implant et la densité osseuse à l'intérieur des filetages ont été déterminées pour les spécimens os/implants. Pour les lits osseux centraux sans implant la quantité osseuse dans les lésions osseuses a été déterminée. Aucune différence significative dans les valeurs de torsion à l'enlèvement n'a été trouvée entre les deux groupes. Les mesures histomorphométriques du contact os/implant et la densité osseuse à l'intérieur des filetages paroïmplantaires ne montraient aucune différence entre les deux groupes ni après deux ni après quatre semaines. Cependant des différences significatives ont été trouvées entre les échantillons à deux et quatre semaines. Dans les lits osseux centraux il n'y avait pas de différence significative de densité osseuse entre le groupe test et le contrôle. L'exposition à la nicotine durant une brève période n'avait pas d'impact significatif sur la guérison osseuse ni sur l'ostéoïntégration d'implants chez les lapines. Zusammenfassung Ziele: Den frühen Einfluss von Nikotin auf die Knochenheilung und Osseointegration zu untersuchen. Material und Methoden: 16 weibliche Kaninchen wurden in zwei Gruppe eingeteilt. Der Testgruppe wurde während 8 Wochen Nikotintartrat gegeben und die Kontrollgruppe bekam ein Placebo. Das Nikotin oder das Placebo wurde mittels einer miniosmotischen Pumpe verabreicht und man bestimmte wöchentlich die Kotininspiegel im Plasma. Bei den Tieren der Testgruppe lieferte die Pumpe 15 mg Nikotin pro Tag. Bei allen Tieren wurden 3 Stellen des Tibiaknochens bearbeitet. In das proximale und distale Knochenbett wurden nach 4 Wochen (rechte Tibia) und nach 6 Wochen (linke Tibia) Implantate eingesetzt. So wurden Gruppen mit einer Heilungszeit von 2 und 4 Wochen kreiert. Bei den distalen Implantaten wurden Ausdrehmoment-Tests (RMT) durchgeführt. Von den zentralen und proximalen Knochenbetten wurden Schliffpräparate angefertigt. Bei den Präparaten mit Implantaten und Knochen bestimmte man den Anteil an mineralisiertem Knochen in Kontakt mit dem Implantat (BIC) und die Knochendichte innerhalb der Gewindegänge (BD-i). Bei den zentralen Knochenbetten ohne Implantate bestimmte man die Knochendichte (BD-c) innerhalb der Knochendefekte. Resutate: Bei den RMT-Werten konnten zwischen der Test- und Kontrollgruppe keine signifikanten Unterschiede gefunden werden. Die histomorphometrischen Messungen des BIC und der periimplantären BD-i zeigten nach 2 oder 4 Wochen keine signifikanten Unterschiede zwischen der Test- und Kontrollgruppe. Jedoch konnten signifikante Unterschiede zwischen den Präparaten nach 2 und 4 Wochen gefunden werden. Bei den zentralen Knochenbetten bestand kein signifikanter Unterschied im BD-c zwischen der Test- und Kontrollgruppe. Schlussfolgerung: Die Verabreichung von Nikotin über einen kurzen Zeitraum hatte keinen signifikanten Einfluss auf die Knochenheilung und Osseointegration bei Kaninchen. Resumen Objetivos: Examinar los efectos a corto plazo de la nicotina en la cicatrización ósea y la osteointegración. Material y Métodos: Se dividieron 16 conejos hembras en dos grupos. El grupo de prueba fue expuesto a tartrato de nicotina durante 8 semanas y el grupo de control fue expuesto a un placebo. La nicotina o el placebo se administraron por medio de una bomba miniosmótica y se midieron e los niveles de nicotina semanalmente. La bomba suministró 15 mg de nicotina/día a los animales del grupo de prueba. Todos los conejos se sometieron a 3 preparaciones tibiales. En los lechos óseos proximales y distales, se colocaron implantes tras 4 semanas (tibia derecha) y 6 semanas (tibia izquierda). Creándose por lo tanto, dos grupos de cicatrización de 2 y 4 semanas. Se llevó a cabo un test de torque de remoción (RMT) en los implantes distales. Se realizaron cortes histológicos de los lechos óseos proximales y centrales. Se determinó la fracción de hueso mineralizado en contacto con el implante (BIC) y la densidad ósea entre las roscas (BD-i) para los especímenes de hueso-implante. Se determinó la densidad ósea (BD-c) en los defectos para los lechos óseos centrales sin implantes. Resultados: No se encontraron diferencias significativas en los valores RMT entre los grupos de prueba y de control. Las mediciones histomorfométricas del BIC y del BD-i periimplantario no mostraron diferencias significativas entre los grupos de prueba y de control tras 2 o tras 4 semanas. De todos modos se encontraron diferencias significativas entre las muestras de 2 y 4 semanas. En los lechos óseos centrales no hubo diferencias significativas en BD-c entre los grupos de prueba y de control. Conclusión: La exposición a la nicotina durante un corto periodo de tiempo no tuvo un impacto significativo en la cicatrización ósea o en la osteointegración implantaria en los conejos. [source] Influence of implant taper on the primary and secondary stability of osseointegrated titanium implantsCLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2004Dominic O'Sullivan Abstract Objectives: The study presented was designed to analyse the mechanical performance and the primary and secondary stability characteristics of endosseous titanium implants with 1° (EXP1) and 2° (EXP2) of taper when compared with the standard Brånemark design (Nobel Biocare AB, Gothenburg, Sweden). Materials and methods: One pair of 10 mm EXP1 and control implants were placed in the femoral condyles of six rabbits. Paired 6 mm EXP1 and control implants and 6 mm EXP2 and control implants were placed in the tibial metaphysis. The control implants used were 4 mm diameter standard Brånemark implants, the same length as the test implants. At placement, insertion torque (IT) and resonance frequency analysis (RFA) measurements were performed. Six weeks postoperatively when the animals were killed, RFA and removal torque (RT) measurements were made. Results: At placement, significantly higher IT was needed to insert the EXP implants compared with the controls. RFA values were significantly higher for EXP1 implants placed in the tibia but not in the femur. In pooling data from the femur and tibia there was a significant difference. The EXP2 implants failed to insert fully and demonstrated a lower RFA value than may have been expected due to the exposed threads, although this difference was not statistically significant. Conclusions: The results from the present study showed that 1° of taper results in a better primary stability compared with the standard Brånemark design. There was no evidence that the tapered design caused negative bone tissue reactions. All the implants gained in stability during the healing period. Résumé L'étude présente a été effectuée pour analyser la performance mécanique et les caractéristiques de stabilité primaire et secondaire d'implants endoosseux en titane avec un taper (fuselé) 1° (EXP1) et 2 (EXP 2) comparés au modèle ad modum Branemark® standard. Une paire d'implants contrôles et un EXP1 de 10 mm ont été placés dans les condyles fémoraux de six lapins. Des paires d'implants contrôles et EXP1 de 6 mm et des implants contrôles et EXP2 de 6 mm ont été placés dans les métaphyses tibiales. Les implants contrôles utilisés avaient un diamètre standard de 4 mm, la même longueur que les implants tests. Lors du placement, des mesures de force d'insertion (IT) et d'analyse de fréquence de résonnance (RFA) ont été effectuées. Six semaines après l'opération lorsque les animaux ont été euthanasiés, les mesures RFA et les forces d'enlèvement (RT) ont été relevées. Lors du placement un IT significativement plus important a été nécessaire pour insérer les implants EXP1 comparé au contrôle. Les valeurs RFA étaient significativement plus importantes pour les implants EXP1 placés dans le tibia mais pas dans le fémur. En rassemblant les données du fémur et du tibia il y avait une différence significative. Les implants EXP2 ne parvenaient pas àêtre insérés à fond et ont montré une valeur RFA inférieure qui n'était pas inattendue vu les filetages exposés bien que ces différences n'étaient pas statistiquement significatives. Les résultats de l'étude présente ont montré que le taper 1 résultait en une stabilité primaire supérieure comparé au modèle ad modum Branemark® standard. Il n'y avait aucun signe que ce nouveau modèle causait des réactions tissulaires osseuses négatives. Tous les implants ont gagné en stabilité durant leur période de guérison. Zusammenfassung Ziele: Die hier vorgestellte Studie hatte zum Ziel, das mechanische Verhalten und die Charakteristika von Primär- und Sekundärstabilität bei enossalen Implantaten mit einer Gewindeneigung von 1° (EXP1) und von 2° (EXP2) zu untersuchen. Man verglich die Daten mit dem Standarddesign von Brånemark (Nobel Biocare AB, Gothenburg, Schweden). Material und Methode: Man implantierte ein Päärchen von 10mm-Implantaten (EXP1 und Kontrollimplantat) in die Femurkondylen von 6 Kaninchen. Zwei weitere Päärchen von 6mm-Implantaten (EXP1 und Kontrollimplantat, sowie EXP2 und Kontrollimplantat) implantierte man in die Metaphyse der Tibia. Bei den Kontrollimplantaten handelte es sich um Standardtypen von Brånemark mit einem Durchmesser von 4 Millimetern und derselben Länge wie die Testimplantate. Bei der Implantation mass man die Kraft, die es zu Eindrehen der Implantate brauchte (IT) und führte Messungen mit der Resonanzfrequenzanalyse (RFA) durch. Sechs Wochen nach der Operation wurden die Tiere geopfert, die RFA erneut durchgeführt und anschliessend der Ausdrehwiderstand (RT) bestimmt. Resultate: Bei der Implantation brauchte es signifikant grössere IT um die EXP-Implantate einzusetzen, als bei den Kontrollimplantaten. Die RFA-Werte waren bei den EXP1-Implantaten, die in die Tibia geschraubt worden waren, signifikant höher. Dies gilt aber nicht für die in den Femur geschraubten Implantate. Wurden die Daten vom Femur mit denen der Tibia verglichen, so erkannte man signifikante Unterschiede. Die EXP2-Implantate konnten nicht vollständig inseriert werden und zeigten auch tiefere RFA-Werte, als man den freiliegenden Schraubenwindungen entsprechend erwarten könnte. Diese Unterschiede waren aber nicht statistisch signifikant. Zusammenfassung: Die Resultate dieser Studie zeigten, das Schraubenwindungen mit 1° Steigung verglichen mit dem Standarddesign von Brånemark eine bessere Primärstabilität erzielten. Man fand andererseits keine Beweise, dass sich dieses neue Design der Schraubenwindungen negativ auf die Reaktion des Knochengewebes auswirkt. Alle Implantate gewannen während in der Heilphase an Stabilität dazu. Resumen Objetivos: El estudio presentado se diseñó para analizar el rendimiento mecánico y las características de estabilidad primaria y secundaria de implantes endoóseos de titanio con 1o (EXP1) y 2o (EXP 2) de autoroscado al compararlos con el diseño estándar de Brånemark (Nobel Biocare AB, Gothenburg, Suecia). Material y Métodos: Se colocó una pareja de implantes de 10 mm EXP1 y de control en los cóndilos femorales de 6 conejos. Se colocaron pareja de implantes de 6 mm EXP1 y de control y de 6 mm EXP2 y de control en la metáfisis tibial. Los implantes de control utilizados fueron Brånemark estándar de 4 mm de diámetro. A la colocación, se llevaron a cabo mediciones del torque de inserción (IT) y del análisis de la frecuencia de resonancia (RFA). Los animales se sacrificaron a las seis semanas de la operación, y se tomaron medidas del torque de remoción (RT). Resultados: Al colocarse, se necesitó un IT significativamente mas alto para insertar los implantes EXP en comparación con los de control. Los valores RFA fueron significativamente mas altos para implantes EXP1 colocados en la tibia pero no en el fémur. Confrontando los datos del fémur y de la tibia apareció una diferencia significativa. Los implantes EXP2 fracasaron en insertarse completamente y demostraron un menor valor de RFA del que se podía esperar debido a la exposición de las roscas, aunque esta diferencia no fue estadísticamente significativa. Conclusiones: Los resultados del presente estudio mostraron que 1o de autoroscado resultan en una mejor estabilidad primaria comparada con el diseño estándar de Brånemark. No hubo evidencia de que el diseño de autoroscado causara reacciones negativas en el tejido óseo. Todos los implantes ganaron estabilidad durante el periodo de cicatrización. [source] Androgen replacement therapy improves function in male rat muscles independently of hypertrophy and activation of the Akt/mTOR pathwayACTA PHYSIOLOGICA, Issue 4 2009C. Hourdé Abstract Aim:, We analysed the effect of physiological doses of androgens following orchidectomy on skeletal muscle and bone of male rats, as well as the relationships between muscle performance, hypertrophy and the Akt/mammalian target of rapamycin (mTOR) signalling pathway involved in the control of anabolic and catabolic muscle metabolism. Methods:, We studied the soleus muscle and tibia from intact rats (SHAM), orchidectomized rats treated for 3 months with vehicle (ORX), nandrolone decanoate (NAN) or dihydrotestosterone (DHT). Results:, Orchidectomy had very little effect on the soleus muscle. However, maximal force production by soleus muscle (+69%) and fatigue resistance (+35%) in NAN rats were both increased when compared with ORX rats. In contrast, DHT treatment did not improve muscle function. The relative number of muscle fibres expressing slow myosin heavy chain and citrate synthase activity were not different in NAN and ORX rats. Moreover, NAN and DHT treatments did not modify muscle weights and cross-sectional area of muscle fibres. Furthermore, phosphorylation levels of downstream targets of the Akt/mTOR signalling pathway, Akt, ribosomal protein S6 and eukaryotic initiation factor 4E-binding protein 1 were similar in muscles of NAN, DHT and ORX rats. In addition, trabecular tibia from NAN and DHT rats displayed higher bone mineral density and bone volume when compared with ORX rats. Only in NAN rats was this associated with increased bone resistance to fracture. Conclusion:, Physiological doses of androgens are beneficial to muscle performance in orchidectomized rats without relationship to muscle and fibre hypertrophy and activation of the Akt/mTOR signalling pathway. Taken together our data clearly indicate that the activity of androgens on muscle and bone could participate in the global improvement of musculoskeletal status in the context of androgen deprivation induced by ageing. [source] Studies on dentin grafts to bone defects in rabbit tibia and mandible; development of an experimental modelDENTAL TRAUMATOLOGY, Issue 1 2009Lars Andersson This property may possibly be used as an alternative or supplement to bone grafting to defective areas after trauma prior to treatment with osseointegrated implants. Hence, the objective of this study was to investigate if dentin can be used as a graft in bone defects in an experimental rabbit model. Materials and Methods:, Eight New Zealand White Rabbits were used to prepare bone cavities either in the angle of the mandible or tibia. Six of the eight tibial and six of the eight mandibular bone defects were filled with dentin blocks from human premolars which were extracted for orthodontic treatment. Two mandibular and two tibial bone cavities were used as controls and all the rabbits were sacrificed after 3 months. Radiographic and histological examinations were performed. Results:, There was a difference in healing pattern between the mandibular and tibial defects. In the mandible, the dentin blocks were resorbed to a larger extent and more often surrounded by fibrous tissue, probably due to the fact that the dentin blocks were mobile because of the thin mandibles and muscular activity in that area. Only some dentin blocks were ankylosed with the mandibular bone. In the tibia however, all dentin blocks were fused to bone over a large area. Osseous replacement resorption was seen. In control cavities, bone formation was seen but was never complete. No signs of inflammatory changes were seen in any fused grafts. Conclusions:, Dentin grafts have a potential to be incorporated in bone without inflammation and can be used as bone inducer and later replaced by bone. Thus, rabbit tibia served as a better model for further studies of this phenomenon when compared to the mandible. [source] Involvement of canonical Wnt/Wingless signaling in the determination of the positional values within the leg segment of the cricket Gryllus bimaculatusDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 2 2007Taro Nakamura The cricket Gryllus bimaculatus is a hemimetabolous insect whose nymphs posses the ability to regenerate amputated legs. Previously, we showed that Gryllus orthologues of Drosophila hedgehog (Gb'hh), wingless (Gb'wg) and decapentaplegic (Gb'dpp) are expressed during leg regeneration and play essential roles in the establishment of the proximal-distal axis. Here, we examined their roles during intercalary regeneration: when a distally amputated tibia with disparate positional values is placed next to a proximally amputated host, intercalary growth occurs in order to regenerate the missing part. In this process, we examined expression patterns of Gb'hh and Gb'wg. We found that expressions of Gb'hh and Gb'wg were induced in a regenerate and the host proximal to the amputated region, but not in the grafted donor distal to the regenerate. This directional induction occurs even in the reversed intercalation. Because these results are consistent with a distal-to-proximal respecification of the regenerate, Gb'wg may be involved in the re-establishment of the positional values in the regenerate. Furthermore, we found that no regeneration occurs when Gb'armadillo (the orthologue of beta-catenin) was knocked down by RNA interference. These results indicate that the canonical Wnt/Wingless signaling pathway is involved in the process of leg regeneration and determination of positional information in the leg segment. [source] Vibration signals from the FT joint can induce phase transitions in both directions in motoneuron pools of the stick insect walking systemDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2003Ulrich Bässler Abstract The influence of vibratory signals from the femoral chordotonal organ fCO on the activities of muscles and motoneurons in the three main leg joints of the stick insect leg, i.e., the thoraco,coxal (TC) joint, the coxa,trochanteral (CT) joint, and the femur,tibia (FT) joint, was investigated when the animal was in the active behavioral state. Vibration stimuli induced a switch in motor activity (phase transition), for example, in the FT joint motor activity switched from flexor tibiae to extensor tibiae or vice versa. Similarly, fCO vibration induced phase transitions in both directions between the motoneuron pools of the TC joint and the CT joint. There was no correlation between the directions of phase transition in different joints. Vibration stimuli presented during simultaneous fCO elongation terminated the reflex reversal motor pattern in the FT joint prematurely by activating extensor and inactivating flexor tibiae motoneurons. In legs with freely moving tibia, fCO vibration promoted phase transitions in tibial movement. Furthermore, ground vibration promoted stance,swing transitions as long as the leg was not close to its anterior extreme position during stepping. Our results provide evidence that, in the active behavioral state of the stick insect, vibration signals can access the rhythm generating or bistable networks of the three main leg joints and can promote phase transitions in motor activity in both directions. The results substantiate earlier findings on the modular structure of the single-leg walking pattern generator and indicate a new mechanism of how sensory influence can contribute to the synchronization of phase transitions in adjacent leg joints independent of the walking direction. © 2003 Wiley Periodicals, Inc. J Neurobiol 56: 125,138, 2003 [source] Appendicular skeleton in Bachia bicolor (Squamata: Gymnophthalmidae): osteology, limb reduction and postnatal skeletal ontogenyACTA ZOOLOGICA, Issue 1 2009Adriana Jerez Abstract The osteology of the appendicular skeleton and its postnatal development are described in Bachia bicolor, a serpentiform lizard with reduced limbs. The pectoral girdle is well developed and the forelimb consists of a humerus, ulna, radius, five carpal elements (ulnare, radiale, distal carpals 4,3, centrale), four metacarpals (II, III, IV, V) and phalanges (phalangeal formula X-2-2-2-2). In the hindlimb, the femur is small and slender, and articulates distally with a series of ossified amorphous and extremely reduced elements that correspond to a fibula, tibia and proximal and distal tarsals 4 and 3. The pelvic girdle consists of ischium, pubis and ilium, but its two halves are widely separated; the ilium is the least reduced element. We describe the ossification and development during postnatal skeletal ontogeny, especially of epiphyseal secondary centres, ossifications of carpal elements, apophyseal ossifications and sesamoids. Compared to other squamates, B. bicolor shows an overall reduction in limb size, an absence of skeletal elements, a fusion of carpal elements, an early differentiation of apophyseal centres, and a low number of sesamoids and apophyseal centres. These observations suggest that the reductions are produced by heterochronic changes during postnatal development and probably during embryonic development; therefore the appendicular skeleton exhibits a pattern of paedomorphic features. [source] Cardiac arrhythmia during propofol sedationEMERGENCY MEDICINE AUSTRALASIA, Issue 5 2008Robert J Douglas Abstract Recent articles have described the increasing frequency of use of propofol as a sedating agent in the ED, and praise the safety profile of propofol when used in this manner. We describe a patient who developed torsade de pointes followed by ventricular fibrillation while undergoing propofol sedation for closed reduction of a mid-shaft fracture of the tibia and fibula. Possible reasons for the event are discussed, and suggestions are made for areas of further research. [source] The application of a scintigraphic grading system to equine tibial stress fractures: 42 casesEQUINE VETERINARY JOURNAL, Issue 4 2003P. H. L. RAMZAN Summary Reasons for performing study: Tibial stress fractures are an important cause of lameness in the Thoroughbred racehorse. While it is recognised that these injuries can vary in clinical presentation and radiographic or scintigraphic appearance, little has been done to quantify lesion severity. By contrast the scintigraphic grading of tibial stress fractures in human athletes is widely reported and assists in the selection of appropriate management regimes. Objectives: To determine the relationship between scintigraphic grade, clinical severity and radiographic appearance of tibial stress fractures. Methods: The current study involved the retrospective analysis of records from 42 Thoroughbreds with abnormal tibial scintigraphic activity. Results: There was a significant association between lesion site and scintigraphic grade and good correlation of scintigraphic scoring between investigators. No significant association was found between scintigraphic grade and either radiographic grade or degree of lameness. Conclusions: The study confirmed that radiographic appearance is an unreliable measure of clinical severity or stage of progression of lesions. The scintigraphic grading system used in the study was not of use in defining stress fracture severity in the equine tibia. Potential relevance: Despite this finding, there is clearly a need for prospective investigations to explore the potential for targeted management regimes for tibial injuries based on lesion site or clinical criteria. [source] Multicentric giant cell tumours in an adolescent with haemophiliaHAEMOPHILIA, Issue 2 2007C.-C. CHANG Summary., ,,Multicentric giant cell tumour (GCTs) of the extremity is prone to be distributed over the age range of 20,40 years, but is rare in haemophilia and in the age before 20. We report a case of a 15-year-old haemophilia boy who presented initially with two radiolucent loci in the right femur and tibia revealed from the X-ray films and then another lesion in the posterior femoral shaft shown from MRI by one year. Differential diagnosis of GCTs should be appraised in various aspects. Radiological diagnostic pitfall was avoided by the pathology disclosed GCTs without malignancy. The early diagnosis of GCTs in haemophilia may be delayed unless appearance of symptoms of pathologic fracture. Coincident multicentric GCTs do occur in haemophilic patients and their incidence might be underestimated, as it might not be judged because immediate symptoms of pain would resolve with appropriate factor replacement." [source] Donor site morbidity after harvesting of proximal tibia boneHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 6 2006Yuan-Chien Chen DDS Abstract Background. Bone-grafting procedures are common in head and neck surgery. Donor site morbidity is an important factor in deciding the site for harvest of cancellous bone. The tibia has been recommended as a harvest site. Use of the proximal tibia as a donor site is associated with few complications. Our present study used proximal tibia bone grafts to reconstruct maxillofacial defects and augment bone volume for implantation. Methods. A retrospective study was undertaken to analyze 40 proximal tibia bone grafts in maxillofacial reconstruction. Minimal follow-up was 6 months. Results. There were no major complications during the follow-up period. Early minor complications (15%) included temporary sensory loss and ecchymosis. Late minor complication (2.5%) was gait disturbance for 2 months. Long-term minor complication (2.5%) was an unsightly scar. Conclusion. The procedure for proximal tibia bone graft is easy, has less operative risk, and results in a lower postoperative morbidity rate. Based on our findings, we believe the proximal tibia offers a reliable site for harvest of sufficient quantities of good-quality cancellous bone. © 2006 Wiley Periodicals, Inc. Head Neck 28:496,500, 2006 [source] TWO NEW SPECIES OF MICROGASTER LATREILLE (HYMENOPTERA: BRACONIDAE) FROM CHINA,INSECT SCIENCE, Issue 3 2000XU Wei-an Abstract The present paper describes two new species of Microgaster Latreille, 1804, viz: M. longiterebra sp. nov. (,) and M. longicaudatus sp. nov. (,). M. longiterebra sp. nov. is described from Kunming, Yunnan Prov. in China closely related to M. subcompletus, but differs from the latter in the combination of the following features: 1) APOL as long as OD; 2) Mesonotum strongly punctate on anterior 2/ 3) r shorter than width of stigma; 4) cu-a of hind wing medially curved; 5) Apex of hypopygium ending far beyond apex of abdomen. M. longicaudatus sp. nov. is described from Tianmushan, Zhejiang Prov. in China closely related to M. ductilis, but differs from the latter in the combination of the following features: 1) middle and hind femora reddish yellow only with apical 1/4 blackish; 2) 1-SR 0.5 times as long as 1-M; 3) the hairy part of ovipositor sheath 0.5 times as long as hind tibia; 4) tergite 3 with slightly weaker rugosity. The type specimens are deposited in Zhejiang University, Hangzhou, China. [source] Morphological changes in the shape of the non-pathological bony knee joint with age: a morphometric analysis of the distal femur and proximal tibia in three populations of known age at deathINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 4 2008S. D. Stevens Abstract This study examines possible morphological variation in the knee joint of Homo sapiens with increasing age in ostensively healthy and non-pathological distal femora and proximal tibiae. Throughout the lifetime of each individual, the hard tissue of the knee undergoes considerable remodelling as a response to biomechanical stresses, changes in bone microarchitecture and reduction of bone mineral content as a concomitant of ageing. The knee is also subject to greater levels of degenerative joint disease than any other joint. If death occurs whilst such diseases are in the earliest stages, initial bone changes may not be visually obvious in museum specimens. If such specimens are used for comparative analyses, it is hypothesised that changes might render it problematic if all ages are conglomerated into discrete samples. This study therefore investigates the degree to which the distal femur and proximal tibia change shape during ageing and, if changes are present, whether they are expressed similarly in males and females. It also examines whether changes are of greater magnitude than those morphological differences which might exist between populations. In an example population of African-Americans, results indicate that there is a statistically significant difference in shape between age groups and those differences become progressively greater between the youngest and oldest adults. Results also show that although morphological variation caused by ageing is apparent, those shape differences attributable to sexual dimorphism are more powerful. When two additional populations are analysed jointly with the African-Americans (Caucasian Americans and the European Spitalfields sample), results indicate that inter-population shape differences are considerably greater than differences caused by increasing age. Results imply that it is justifiable to combine specimens of all ages into discrete samples for comparative purposes. Copyright © 2007 John Wiley & Sons, Ltd. [source] Sexual dimorphism in limb bones of ibex (Capra ibex L.): mixture analysis applied to modern and fossil dataINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 5 2007H. Fernández Abstract Estimating sex ratios of fossil bone assemblages is an important step in the determination of demographic profiles, which are essential for understanding the palaeobiology and palaeoethology of any particular species, as well as its exploitation patterns by humans. This is especially true for ibex (Capra ibex), which was a main source of food for hominids during Pleistocene times. Classical methods for determining sexual dimorphism and sex ratio, such as analyses using uni- and bivariate plots, are based on an arbitrary fixing of limits between sexes. Here we use a more robust statistical method termed mixture analysis (MA) to determine the sex of postcranial remains (long bones, metapodials and tarsals) from ibex. For the first time, we apply MA to both a modern and a fossil sample of one species, by using metric data taken from (i) a collection of present-day ibex skeletons and (ii) a Palaeolithic sample of the same species. Our results clearly show that the forelimb (humerus and radius) is more dimorphic than the hindlimb (femur and tibia) and is therefore better suited for sexing ibex. It also appears that metapodials should be used carefully for estimating sex ratios. On the basis of these results, we propose a classification of bone measurements that are more or less reliable for sexing ibex. The results of MA applied to the ibex fossil bones from the Upper Palaeolithic site of the Observatoire (Monaco) lead us to the conclusion that this assemblage consists of a majority of males. The quantitative estimations calculated by the MA make it possible to compare the size of Pleistocene and modern ibex for the whole set of variables used in this study. Copyright © 2006 John Wiley & Sons, Ltd. [source] A pre-Columbian case of congenital syphilis from Anatolia (Nicaea, 13th century AD)INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 1 2006Y. S. ErdalArticle first published online: 16 AUG 200 Abstract In this study, the skeleton of an approximately 15-year-old child, dating back to the Late Byzantine period (13th century AD) is examined with the aim of determining where this specimen fits in the continuing arguments on the origins of syphilis. It was unearthed during an excavation at an amphitheatre in Nicaea dating to the Roman period. The Nicaea specimen displays common symptoms found in the majority of people with congenital syphilis such as Hutchinson's incisor, mulberry molar, darkened enamel, radial scar on frontal bone, sabre tibia, syphilitic dactylitis, and gummatous and non-gummatous osteomyelitis on almost every post-cranial bone. Because of the sub-periosteal new bone formation, the medullary spaces in some long bones are narrowed or completely obliterated. These lesions, which were observed via macroscopic and radiological examination, reflect the late stages of congenital syphilis. The specimen, when examined together with increasing numbers of other finds from the Old World, contributes to the argument that venereal syphilis did exist in the Old World before 1493, and brings forward the need to revise the Columbian hypothesis, which maintains that syphilis is a new disease carried to the Old World from the New World by Columbus' crew. Copyright © 2005 John Wiley & Sons, Ltd. [source] A foot deformity from a Romano-British cemetery at Gloucester, England, and the current evidence for talipes in palaeopathologyINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 5 2004C. A. Roberts Abstract A male skeleton from the Romano-British site at Kingsholm, Gloucester, is described with abnormalities in the humerus, femur, tibia, fibula and foot. Computed tomography of the femora to enable cross-sectional analysis suggested altered normal gait to compensate for the deformity. Differential diagnoses are considered and a diagnosis of clubfoot deformity is suggested. Palaeopathological evidence for clubfoot is rare in the literature but the cases reported to date are reviewed. Copyright © 2004 John Wiley & Sons, Ltd. [source] Bone remodelling following a lower leg fracture in the 11,000-year-old hunter-gatherer from Vado all' Arancio (Italy)INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 6 2002B. M. Holt Abstract The Upper Palaeolithic skeleton from Vado all'Arancio (Italy), dated to about 11,330 BP, exhibits a severe ankle fracture healed with residual deformation. Following recovery, this young hunter-gatherer continued to walk for an extended period of time, albeit in a mechanically altered manner. While right-left differences in external lower limb bone measurements are relatively low, biomechanical analysis of femur and tibia indicates unusually pronounced asymmetry in all cross-sectional measures of diaphyseal strength. Asymmetry results primarily from normal side endosteal hypertrophy, and not from hypotrophy of the injured limb, suggesting that this individual resumed active life following recovery. This pattern of asymmetry underscores the role of physical activity in maintaining bone mass. Copyright © 2002 John Wiley & Sons, Ltd. [source] Two ,Medical' Cases from Medieval OsloINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 3 2002Per Holck Abstract An Erratum has been published for this article in International Journal of Osteoarchaeology 15(2) 2005, 153,154. More than one century of archaeological excavations in Oslo has brought several thousand medieval skeletons to light. Many of these are silent witnesses of the health conditions in the Norwegian capital during the 12th,16th centuries. This paper presents a description of two cases of special interest. One is a tibia that shows traces of cut marks due to a severe osteomyelitis; the other one has a depression in the bregma area which has perforated the skull roof and led to an inflammation of the bone surface. Both cases are probably proofs of deliberate medical care and skill of a high professional standard at that time. Copyright © 2002 John Wiley & Sons, Ltd. [source] A method to establish the relationship between chronological age and stage of union from radiographic assessment of epiphyseal fusion at the knee: an Irish population studyJOURNAL OF ANATOMY, Issue 2 2008J. E. O'Connor Abstract Characteristic changes during epiphyseal union provide a skeletal age, which when compared with age-based standards provides an estimation of chronological age. Currently there are no data on epiphyseal union for the purposes of age estimation specific to an Irish population. This cross-sectional study aims to investigate the relationship between stage of epiphyseal union at the knee joint and chronological age in a modern Irish population. A novel radiographic method that sub-divides the continuum of development into five specific stages of union is presented. Anteroposterior and lateral knee radiographs of 148 males and 86 females, aged 9,19 years, were examined. Fusion was scored as Stage 0, non-union; Stage 1, beginning union; Stage 2, active union; Stage 3, recent union; or Stage 4, complete union. Stage of epiphyseal union is correlated with chronological age in both males and females. Mean age gradually increases with each stage of union and also varies between male and female subjects. A statistically significant difference in mean age was recorded between stages when compared to the previous stage, for the three epiphyses. Irish children are comparable to those from previously published studies with epiphyseal union in females occurring earlier than males. A significant difference was noted between the mean age of union for males and females for each of Stages 1 and 2 for the femur and Stages 0, 1, 2 and 3 for the tibia and the fibula. The results also suggest that the stages of union occur at earlier ages in this Irish population. Implementation of standardized methodology is necessary to investigate if this is due to a secular or population variation in maturation or to a methodology which clearly identifies five stages of union. [source] Anatomics: the intersection of anatomy and bioinformaticsJOURNAL OF ANATOMY, Issue 1 2005Jonathan B. L. Bard Abstract Computational resources are now using the tissue names of the major model organisms so that tissue-associated data can be archived in and retrieved from databases on the basis of developing and adult anatomy. For this to be done, the set of tissues in that organism (its anatome) has to be organized in a way that is computer-comprehensible. Indeed, such formalization is a necessary part of what is becoming known as systems biology, in which explanations of high-level biological phenomena are not only sought in terms of lower-level events, but are articulated within a computational framework. Lists of tissue names alone, however, turn out to be inadequate for this formalization because tissue organization is essentially hierarchical and thus cannot easily be put into tables, the natural format of relational databases. The solution now adopted is to organize the anatomy of each organism as a hierarchy of tissue names and linking relationships (e.g. the tibia is PART OF the leg, the tibia IS-A bone) within what are known as ontologies. In these, a unique ID is assigned to each tissue and this can be used within, for example, gene-expression databases to link data to tissue organization, and also used to query other data sources (interoperability), while inferences about the anatomy can be made within the ontology on the basis of the relationships. There are now about 15 such anatomical ontologies, many of which are linked to organism databases; these ontologies are now publicly available at the Open Biological Ontologies website (http://obo.sourceforge.net) from where they can be freely downloaded and viewed using standard tools. This review considers how anatomy is formalized within ontologies, together with the problems that have had to be solved for this to be done. It is suggested that the appropriate term for the analysis, computer formulation and use of the anatome is anatomics. [source] Dietary phytate (inositol hexaphosphate) regulates the activity of intestinal mucosa phytaseJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 5 2009E. M. Onyango Summary The role of dietary phytate (inositol hexaphosphate) in the regulation of intestinal mucosa phytase was investigated in chicks. Seven-day-old chicks were grouped by weight into six blocks of three cages with six birds per cage. Three purified diets [a chemically defined casein diet, a chemically defined casein diet plus sodium phytate (20 g/kg diet) and a chemically defined casein diet plus sodium phytate (20 g/kg diet) and microbial phytase (1000 units/kg diet)] were randomly assigned to cages within each block. Chicks were fed experimental diets from 8 to 22 days of age then killed, and duodenal mucosa and left tibia removed. Phytase activity in duodenal mucosa, growth performance and bone ash content were determined. Addition of phytate to the chemically defined casein diet reduced (p < 0.05) the Vmax of the duodenal brush border phytase, but the Km of the enzyme was not affected. Addition of phytate also reduced (p < 0.05) weight gain, feed intake, feed efficiency and percentage ash. Addition of microbial phytase fully restored the feed efficiency (p < 0.05), but Vmax and body weight gain were only partially restored (p < 0.05). In conclusion, it would seem that dietary phytates non-competitively inhibit intestinal mucosa phytase. [source] In vivo evaluation of hydroxyapatite foamsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 4 2002P. Sepulveda Abstract Hydroxyapatite (HA) is widely applied as bone graft material due to its osteoconductive potential and well-established biocompatibility. In this work, macroporous hydroxyapatite structures made through foaming of aqueous suspensions and gelcasting were tested for in vivo osteointegration. These foams are composed of a three-dimensional array of spherical pores with diameters of approximately 100,500 ,m, interconnected by windows of smaller size in the range of 30,120 ,m. The HA foams were implanted in the tibia of albino New Zealand rabbits and removed after a period of 8 weeks. Histological analysis revealed that the pores in the foams were partially or completely filled progressively with mature new bone tissue and osteoid after the implanted period. No immune or inflammatory reactions were detected. The high osteoconductive potential of the HA foams provides a potential structure for use as bone substitute in orthopedic, oral, and cranio-maxillofacial reconstructive surgery, and as dento-alveolar implants. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 587,592, 2002 [source] In vitro change in mechanical strength of ,-tricalcium phosphate/copolymerized poly- L -lactide composites and their application for guided bone regenerationJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2002Masanori Kikuchi Abstract Novel composites of bioactive ,-tricalcium phosphate [Ca3(PO4)2] and biodegradable copolymerized poly- L -lactide (CPLA) were prepared by a heat-kneading method. The mechanical and chemical changes of the composites were evaluated in vitro by soaking in physiological saline and Dulbecco's phosphate buffered saline. When soaked in physiological saline, the 3-point mechanical strength decreased rapidly from 60 to 30 MPa in the initial 4 weeks and then gradually reached a plateau; the initial decrease in the mechanical strength was ascribed to the dissolution of ,-tricalcium phosphate from the surface. The mechanical properties evident at 8,12 weeks were sufficient for the composites to be used as a biodegradable material for regeneration of bone because the hydrolysis of CPLA was inhibited in both physiological saline and phosphate-buffered saline as a result of a pH-buffering effect. Composite membranes 250-,m thick were used to regenerate large bone defects in beagle dogs: 10 × 10 × 10 mm3 in volume in the mandible and 20 mm in length in the tibia. The afflicted areas covered with the composite membranes were almost perfectly filled with new bone 12 weeks after the operation, whereas those covered with a CPLA membrane or without any membranes were invaded by soft tissue. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 265,272, 2002 [source] Mechanical implications of estrogen supplementation in early postmenopausal womenJOURNAL OF BONE AND MINERAL RESEARCH, Issue 6 2010Felix W Wehrli Abstract Whereas the structural implications of drug intervention are well established, there are few data on the possible mechanical consequences of treatment. In this work we examined the changes in elastic and shear moduli (EM and SM) in a region of trabecular bone in the distal radius and distal tibia of early postmenopausal women on the basis of MRI-based micro-finite-element (µFE) analysis. Whole-section axial stiffness (AS) encompassing both trabecular and cortical compartments was evaluated as well. The study was conducted on previously acquired high-resolution images at the two anatomic sites. Images were processed to yield a 3D voxel array of bone-volume fraction (BVF), which was converted to a µFE model of hexahedral elements in which tissue modulus was set proportional to voxel BVF. The study comprised 65 early postmenopausal women (age range 45 to 55 years), of whom 32 had chosen estrogen supplementation (estradiol group); the remainder had not (control group). Subjects had been scanned at baseline and 12 and 24 months thereafter. At the distal tibia, EM and SM were reduced by 2.9% to 5.5% in the control group (p,<,.05 to <.005), but there was no change in the estradiol subjects. AS decreased 3.9% (4.0%) in controls (p,<,.005) and increased by 5.8% (6.2%) in estradiol group subjects (p,<,.05) at 12 (24) months. At the distal radius, EM and SM changes from baseline were not significant, but at both time points AS was increased in estradiol group subjects and decreased in controls (p,<,.005 to <.05), albeit by a smaller margin than at the tibia. EM and SM were strongly correlated with BV/TV (r2,=,0.44 to 0.92) as well as with topologic parameters expressing the ratio of plates to rods (r2,=,0.45 to 0.82), jointly explaining up to 96% of the variation in the mechanical parameters. Finally, baseline AS was strongly correlated between the two anatomic sites (r2,=,0.58), suggesting that intersubject variations in the bone's mechanical competence follows similar mechanisms. In conclusion, the results demonstrate that micro-MRI-based µFE models are suited for the study of the mechanical implications of antiresorptive treatment. The data further highlight the anabolic effect of short-term estrogen supplementation. © 2010 American Society for Bone and Mineral Research [source] Bone microstructure at the distal tibia provides a strength advantage to males in late puberty: An HR-pQCT studyJOURNAL OF BONE AND MINERAL RESEARCH, Issue 6 2010Melonie Burrows Abstract Bone is a complex structure with many levels of organization. Advanced imaging tools such as high-resolution (HR) peripheral quantitative computed tomography (pQCT) provide the opportunity to investigate how components of bone microstructure differ between the sexes and across developmental periods. The aim of this study was to quantify the age- and sex-related differences in bone microstructure and bone strength in adolescent males and females. We used HR-pQCT (XtremeCT, Scanco Medical, Geneva, Switzerland) to assess total bone area (ToA), total bone density (ToD), trabecular bone density (TrD), cortical bone density (CoD), cortical thickness (Cort.Th), trabecular bone volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), trabecular spacing standard deviation (Tb.Sp SD), and bone strength index (BSI, mg2/mm4) at the distal tibia in 133 females and 146 males (15 to 20 years of age). We used a general linear model to determine differences by age- and sex-group and age,×,sex interactions (p,<,0.05). Across age categories, ToD, CoD, Cort.Th, and BSI were significantly lower at 15 and 16 years compared with 17 to 18 and 19 to 20 years in males and females. There were no differences in ToA, TrD, and BV/TV across age for either sex. Between sexes, males had significantly greater ToA, TrD, Cort.Th, BV/TV, Tb.N, and BSI compared with females; CoD and Tb.Sp SD were significantly greater for females in every age category. Males' larger and denser bones confer a bone-strength advantage from a young age compared with females. These structural differences could represent bones that are less able to withstand loads in compression in females. © 2010 American Society for Bone and Mineral Research [source] Correlates of trabecular and cortical volumetric bone mineral density of the radius and tibia in older men: The osteoporotic fractures in men studyJOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2010Kamil E Barbour Abstract Quantitative computed tomography (QCT) can estimate volumetric bone mineral density (vBMD) and distinguish trabecular from cortical bone. Few comprehensive studies have examined correlates of vBMD in older men. This study evaluated the impact of demographic, anthropometric, lifestyle, and medical factors on vBMD in 1172 men aged 69 to 97 years and enrolled in the Osteoporotic Fractures in Men Study (MrOS). Peripheral quantitative computed tomography (pQCT) was used to measure vBMD of the radius and tibia. The multivariable linear regression models explained up to 10% of the variance in trabecular vBMD and up to 9% of the variance in cortical vBMD. Age was not correlated with radial trabecular vBMD. Correlates associated with both cortical and trabecular vBMD were age (,), caffeine intake (,), total calcium intake (+), nontrauma fracture (,), and hypertension (+). Higher body weight was related to greater trabecular vBMD and lower cortical vBMD. Height (,), education (+), diabetes with thiazolidinedione (TZD) use (+), rheumatoid arthritis (+), using arms to stand from a chair (,), and antiandrogen use (,) were associated only with trabecular vBMD. Factors associated only with cortical vBMD included clinic site (,), androgen use (+), grip strength (+), past smoker (,), and time to complete five chair stands (,). Certain correlates of trabecular and cortical vBMD differed among older men. An ascertainment of potential risk factors associated with trabecular and cortical vBMD may lead to better understanding and preventive efforts for osteoporosis in men. © 2010 American Society for Bone and Mineral Research [source] Parathyroid hormone (PTH),induced bone gain is blunted in SOST overexpressing and deficient miceJOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2010Ina Kramer Abstract Intermittent parathyroid hormone (PTH) treatment is a potent bone anabolic principle that suppresses expression of the bone formation inhibitor Sost. We addressed the relevance of Sost suppression for PTH-induced bone anabolism in vivo using mice with altered Sost gene dosage. Six-month-old Sost overexpressing and 2-month-old Sost deficient male mice and their wild-type littermates were subjected to daily injections of 100,µg/kg PTH(1,34) or vehicle for a 2-month period. A follow-up study was performed in Sost deficient mice using 40 and 80,µg/kg PTH(1,34). Animals were sacrificed 4 hours after the final PTH administration and Sost expression in long bone diaphyses was determined by qPCR. Bone changes were analyzed in vivo in the distal femur metaphysis by pQCT and ex vivo in the tibia and lumbar spine by DXA. Detailed ex vivo analyses of the femur were performed by pQCT, µCT, and histomorphometry. Overexpression of Sost resulted in osteopenia and Sost deletion in high bone mass. As shown before, PTH suppressed Sost in wild-type mice. PTH treatment induced substantial increases in bone mineral density, content, and cortical thickness and in aging wild-type mice also led to cancellous bone gain owing to amplified bone formation rates. PTH-induced bone gain was blunted at all doses and skeletal sites in Sost overexpressing and deficient mice owing to attenuated bone formation rates, whereas bone resorption was not different from that in PTH-treated wild-type controls. These data suggest that suppression of the bone formation inhibitor Sost by intermittent PTH treatment contributes to PTH bone anabolism. © 2010 American Society for Bone and Mineral Research [source] | |||||||||||||||||||