El peroné: mal alumno, pero buen profesor. (¿Qué tiene prioridad biológica: la integridad, o la supervivencia?) / Fibula: a bad pupil but a good profesor. (What comes first, integrity or survival?)

La concepción original del mecanostato como un regulador de la rigidez estructural ósea orientado a mantener un determinado 'factor de seguridad' en todos los esqueletos parece no corresponder por igual a cualquier hueso y para cualquier tipo de estímulo. Hemos descubierto que la estructura cortical diafisaria del peroné humano manifiesta un comportamiento ambiguo del sistema, referido al uso del pie. La diáfisis peronea, además de ser insensible al desuso, se rigidiza, como sería de esperar, por entrenamientos en disciplinas deportivas que rotan o revierten el pie (hockey, fútbol, rugby); pero, llamativamente, se flexibiliza en su mitad proximal por entrenamiento en carrera larga, que optimiza el rendimiento del salto que acompaña a cada paso. La referida rigidización robustecería la región peronea de inserción de los músculos que rotan o revierten el pie, favoreciendo la locomoción sobre terrenos irregulares o 'gambeteando', propia de especies predadoras como los leopardos. La 'inesperada' flexibilización proximal, pese a reducir la resistencia a la fractura por flexión lateral (poco frecuente en el hombre), favorecería la absorción elástica de la energía contráctil de la musculatura inserta, optimizando el rendimiento del salto al correr, condición vital para especies presas como las gacelas. La falta de analogía de estas respuestas de la estructura peronea a distintos entrenamientos, incompatible con el mantenimiento de un factor de seguridad, sugiere su vinculación preferencial con la optimización de aptitudes esqueléticas con valor selectivo. Esto ampliaría el espectro regulatorio del mecanostato a propiedades esqueléticas 'vitales', más allá del control de la integridad ósea. Su manifestación en el hombre, ajena a connotaciones selectivas (quizá resultante del mantenimiento de genes ancestrales), permitiría proponer la indicación de ejercicios orientados en direcciones preferenciales a este respecto, especialmente cuando estas coincidieran con las de las fuerzas que podrían fracturar al hueso. (AU)

The original notion of the mechanostat as a regulator of bone structural rigidity oriented to maintain a certain 'safety factor' in all skeletons does not seem to correspond equally to every bone and for any type of stimulus. We have discovered that the diaphyseal cortical structure of the human fibula shows an ambiguous behavior of the system, with reference to the use of the foot. The peroneal shaft, in addition to being insensitive to disuse, becomes stiffened, as might be expected, by training in sport disciplines that involve rotating or reversing the foot (hockey, soccer, rugby); but, remarkably, it becomes more flexible in its proximal half by long-distance running training, which optimizes the performance of the jump that accompanies each step. The stiffening would strengthen the peroneal region of insertion of the muscles that rotate or reverse the foot, favoring locomotion on uneven terrain or 'dribbling', typical of predatory species such as leopards. The 'unexpected' proximal flexibilization, despite reducing the resistance to lateral flexion fracture (rare in human), would favor the elastic absorption of contractile energy from the inserted muscles, optimizing jumping performance when running, a vital condition for prey species such as gazelles. The lack of analogy of these responses of the peroneal structure to different training, incompatible with the maintenance of a safety factor, suggests its preferential link with the optimization of skeletal aptitudes with selective value. This would expand the regulatory spectrum of the mechanostat to 'vital' skeletal properties, beyond the control of bone integrity. Its manifestation in humans, oblivious to selective connotations (perhaps resulting from the maintenance of ancestral genes), would make it possible to propose the indication of exercises oriented in preferential directions, especially when they coincide with the direction of the forces that could fracture the bone. (AU)

Demostración original de la interferencia de los efectos modeladores corticales expansivos de un entrenamiento sobre los de otro ulterior: (la modelación 'marca el terreno' para la remodelación) / Original demonstration of the interference of the expansive cortical modeling effects of one training on those of another further training: (modeling "sets limits" for remodeling)

La expansión modeladora de la geometría cortical de un hueso inducida por su entorno mecánico podría ser difícil de modificar por estímulos ulteriores con diferente direccionalidad. Este estudio, que por primera vez combina datos tomográficos del peroné (pQCT) y dinamométricos de la musculatura peronea lateral, intenta demostrar que, en individuos jóvenes no entrenados, el entrenamiento en fútbol produce cambios geométricos peroneos expansivos, similares a los del rugby, que podrían interferir en los efectos de un entrenamiento ulterior direccionalmente diferente (carrera larga). Confirmando la hipótesis, los resultados indican, con evidencias originales, 1) la relevancia creciente del uso del pie (rotación externa y eversión provocadas por los peroneos laterales) para la determinación de la geometría peronea (incremento del desarrollo de los indicadores de masa y de diseño óseos), evidenciada por la secuencia creciente de efectos: carrera < fútbol < rugby; 2) la predominancia de esos efectos sobre el desarrollo centro-proximal del peroné para resistir a la flexión lateral, y en la región distal para resistir el buckling (principal sitio y causa de fractura del hueso) y 3.) la relevancia de la anticipación de esos efectos para interferir en la manifestación de los cambios producidos por un entrenamiento ulterior (carrera), cuando los del primero (fútbol) afectan la modelación cortical de modo expansivo. Esta última deducción demuestra, en forma inédita, que un cambio modelatorio expansivo tempranamente inducido sobre la estructura cortical ósea 'delimitaría el terreno'para la manifestación de cualquier otro efecto ulterior por estímulos de distinta direccionalidad. (AU)

The modeling-dependent, geometrical expansion of cortical bone induced by the mechanical environment could be hard to modify by subsequent stimulations with a different directionality. The current study aimed to demonstrate that in young, untrained individuals, training in soccer or rugby enhances the geometric properties of the fibula cortical shell in such a way that the geometrical changes could interfere on the effects of a second training in which the loads are induced in a different direction, e.g. long-distance running. The original findings reported herein confirm our hypothesis and support 1) The relevance of the use of the foot (external rotation and eversion produced by peroneus muscles) to determine fibula geometry (improved development of indicators of bone mass and design) as evidenced by the increasing nature of the effects induced by running < soccer < rugby trainings; 2) The predominance of those effects on the ability of the fibula to resist lateral bending in the centralproximal region (insertion of peroneus muscles), and to resist buckling in the distal region (the main cause and site of the most frequent bone fractures), and 3) The interaction of the effects of a previous training with those of a subsequent training with a different orientation of the loads when the former induced a modeling-dependent expansion of the cortex. Our results support the proposed hypothesis with original arguments by showing that a first, expansive effect induced on cortical bone modeling would set the stage the manifestation of any subsequent effect derived from mechanical stimuli. (AU)

¿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)

Study progressing on the effect of bone structural abnormalities on the distal radioulnar joint stability / 中国骨伤

The distal radioulnar joint is not only the main load-bearing joint in the wrist, but also the pivot of the rotation of the forearm. It is one of the most important and unique joints in the body. Maintaining the stability of the distal radioulnar joint is very important for our daily life. The tissue to stabilize the distal radioulnar joint includes bone structures and soft tissue structures. Although the contribution of soft tissue structures to its stability is far exceeding that of bone structures, the influence of abnormal bone structure on the distal radioulnar joint cannot be ignored. By reviewing the relevant literatures, this article divides the bone structural abnormalities into congenital and acquired bone structural abnormalities. The effects of congenital and acquiredbone structural abnormalities on the distal radioulnar joint stability are analysized and collated in this article, and its clinical symptoms, clinical grading, clinical treatments are also summerized. The problems of distal radioulnar joint instability in clinical practicing and its future researching directions are briefly described in order to provide some suggestions for future clinical applications.

Kelulut honey ameliorates glucocorticoid induced osteoporosis via its antioxidant activity in rats

Objective: To explore the effects of kelulut honey on bone structure and histomorphometry against glucocorticoid-induced osteoporosis. Methods: Thirty-five male rats were used (n = 7). Twenty-eight adrenalectomized rats were divided into four groups; each group was given normal saline 0.9% (negative control), calcium water (positive control), kelulut honey (200 mg/kg/day and 400 mg/kg/day, respectively) treatment, respectively. All of them were administered with intramuscular injection of dexamethasone (120 μg/kg/day) to induce osteoporosis. Seven sham operated rats were given vehicle palm olein 0.05 mL/100 g/day by intramuscular injection and 0.1 mL/kg/day orally. All the treatments were given daily for 2 month. Lipid peroxidation and oxidative stress enzymes were measured. In addition, bone structural and histomorphometry analyses were also conducted. Results: Two-month glucocorticoid treatment increased the level of malondialdehyde and decreased superoxide dismutase significantly. No significant changes were found in the activities of catalase and glutathion peroxidase. Bone volume/tissue volume and trabecular number were significantly reduced while trabecular separation of the femoral bones was increased which corresponded to the decreased number of osteoblast surface after two months of receiving glucocorticoid treatment. Kelulut honey treatment restored the level of superoxide dismutase and reduced malondialdehyde significantly (P<0.05). Moreover, kelulut honey increased bone volume/tissue volume, trabecular number and decreased trabecular separation significantly (P<0.05), which were further confirmed by increased osteoblast surface and decreased osteoclast surface number (P<0.05). Conclusions: Kelulut honey may have potential bone protective effect, and may be a prophylaxis against glucocorticoid-induced osteoporosis.

Kelulut honey ameliorates glucocorticoid induced osteoporosis via its antioxidant activity in rats

Objective: To explore the effects of kelulut honey on bone structure and histomorphometry against glucocorticoid-induced osteoporosis. Methods: Thirty-five male rats were used (n = 7). Twenty-eight adrenalectomized rats were divided into four groups; each group was given normal saline 0.9％ (negative control), calcium water (positive control), kelulut honey (200 mg/kg/day and 400 mg/kg/day, respectively) treatment, respectively. All of them were administered with intramuscular injection of dexamethasone (120 μg/kg/day) to induce osteoporosis. Seven sham operated rats were given vehicle palm olein 0.05 mL/100 g/day by intramuscular injection and 0.1 mL/kg/day orally. All the treatments were given daily for 2 month. Lipid peroxidation and oxidative stress enzymes were measured. In addition, bone structural and histomorphometry analyses were also conducted. Results: Two-month glucocorticoid treatment increased the level of malondialdehyde and decreased superoxide dismutase significantly. No significant changes were found in the activities of catalase and glutathion peroxidase. Bone volume/tissue volume and trabecular number were significantly reduced while trabecular separation of the femoral bones was increased which corresponded to the decreased number of osteoblast surface after two months of receiving glucocorticoid treatment. Kelulut honey treatment restored the level of superoxide dismutase and reduced malondialdehyde significantly (P<0.05). Moreover, kelulut honey increased bone volume/tissue volume, trabecular number and decreased trabecular separation significantly (P<0.05), which were further confirmed by increased osteoblast surface and decreased osteoclast surface number (P<0.05). Conclusions: Kelulut honey may have potential bone protective effect, and may be a prophylaxis against glucocorticoid-induced osteoporosis.

Role of bone status in anterolateral portion of femoral head in the progression of osteonecrosis of the femoral head / 中国组织工程研究

BACKGROUND:Mechanical stress plays an important role in the progressive collapse in osteonecrosis of the femoral head.Therefore,the bone structure of weight-bearing area may be the risk factor for collapse.OBJECTIVE:To investigate the relationship between the bone preservation of weight-bearing area and collapse progression in necrotic femoral head.METHODS:Eighty-seven patients (102 hips) with ARCO stage Ⅱ osteonecrosis of the femoral head,diagnosed by MRI,were enrolled.All patients underwent a natural progression.Collapse and bone involvement of the weight-bearing area were viewed by anteroposterior and frog-leg lateral radiographs.According to the location of the necrotic lesion on the anterolateral portion of the femoral head,the necrosis was divided into three types:type 1,the posteromedial and central portions;type 2,part of the anterolateral portion;type 3,the entire anterolateral portion.The collapse rate and the time to collapse in different types were assessed.RESULTS AND CONCLUSION:(1) All patients were followed up for 3-58 months.(2) Of the 60 hips with collapse,46 (76.7％) hip collapse was identified on anteroposterior radiograph.On frog-leg lateral radiograph showing collapsed femoral head could be identified in 57 (95.0％) hips,which was significantly different (P ＜ 0.01).(3) In all 102 hips,the collapse rate in type 3 osteonecrosis of the femoral head was significantly higher than that of type 2 osteonecrosis of the femoral head (P ＜ 0.001),and the time to collapse was markedly shortened.None collapse occurred in all six hips with type Ⅰ osteonecrosis of the femoral head during follow-up.(4) In summary,preservation of anterolateral portion is associated with potential collapse progression in necrotic femoral head.

The optimal element size, material property distributions and modeling methods for finite element modeling of lumbar vertebra / 医用生物力学

Objective To investigate the effects of element size and type, material property distributions of vertebral cancellous bone and simulation methods of cortical bone structure on the finite element (FE) results during the finite element modeling of lumbar vertebral body. Methods Based on QCT images of lumbar spine, 22 FE models of L2 without posterior structure were built by 6 element sizes (0.5, 1.0, 1.5, 2.0, 2.5, 3.0 mm), 2 heterogeneous material distribution methods of cancellous bone (300, 150) and 2 cortical bone modeling methods. The maximum displacement, strain energy, average stress and axial stiffness of these models were obtained to analyze and verify the results. Results When the element size was 0.5 mm, the axial stiffness of models with 10, 150 and 300 kinds of heterogeneous materials showed obvious differences; for the vertebral cancellous bone with 150 kinds of materials, the variation of average stress was not distinct under different element sizes; the average stress of the model using the outermost hexahedral elements to simulate the cortical bone structure was larger than that appending the skin to the outmost of the model. Conclusions It is more reasonable and effective to build the FE model of lumbar vertebral body with the method by 0.5 mm element size, 8-noded hexahedral elements, 150 kinds of heterogeneous materials, and using the outermost hexahedral elements to simulate the cortical bone structure. The research findings will lay a foundation for building subject-specific FE models of lumbar vertebral body on a large scale in future.

Three-dimensional structure and morphology of the mandible in type 1 diabetes mellitus mice / 中国组织工程研究

BACKGROUND: Diabetes mel itus is one of the most common systemic diseases, which often leads to the changes of the jaw and other bone structure, as wel as the abnormal changes of mineral metabolism. OBJECTIVE: To observe the three-dimensional structure and histopathological changes of the mandible in type 1 diabetes mel itus mice. METHODS: The mice were randomly divided into control group and diabetes mel itus group. The diabetes mel itus group received intraperitoneal injection of 50 mg/kg streptozotocin for 5 days to establish a type 1 diabetes mel itus model, and the control group received intraperitoneal injection of citrate buffer. RESULTS AND CONCLUSION: At 3 weeks after modeling, the micro-CT technique was used to observe the three-dimensional structure of the mandibles in the two groups. The quantitative analysis on the microstructure of cancel ous bone and cortical bone showed that the bone mineral density, bone volume fraction, trabecular number and trabecular thickness of cancel ous bone in the interest region in the mandible of type 1 diabetes mel itus mice were significantly decreased when compared with that in the control group (P < 0.01, P < 0.05), while the structure model index was increased significantly (P < 0.05); the mineral density and area of cortical bone were decreased in the diabetes mel itus group (P < 0.05). Hematoxylin-eosin staining showed that the number and volume of mandibular trabeculae of type 1 diabetes mel itus mice were decreased. The results suggest that the three-dimensional structure of the cancel ous bone and cortical bone in the streptozotocin-induced type 1 diabetes mel itus mice are changed significantly, and the microstructure change of the cancel ous bone is more obvious.

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.

Radiological Morphometric Analysis for the Trabecular Bone Structure of Mandibular Condyle after Ovariectomy in Mature Cynomolgus Monkeys / Oral Science International

To investigate the effects of experimental osteoporosis on the trabecular structure of the mandibular condyle in cynomolgus monkeys by radiological bone morphometry, ovariectomy (OVX) was performed on 10-year-old female cynomolgus monkeys, which were fed a controlled diet for 2 years. Ten sham control groups were fed under the same conditions. Using a microfocus tube and computed radiography, the removed mandibular condyle samples were imaged by standardized magnification radiography. The structural parameters were measured using radiological bone morphometric analysis. The bone mineral density (BMD) was measured by dual energy X-ray absorptiometry. The thickness of the cortical bone was measured using magnified radiographic images. The thickness of the cortical bone and the BMD in the OVX group were significantly lower than in the sham group. In the results of skeletal structure of the mandibular condyle, the trabecular structure of the mandibular condyle was markedly deteriorated in the OVX group. The trabecular structure of the mandibular condyle for the OVX group was significantly decreased, thus it was suggested that osteoporosis is a potential risk factor of osteoarthritis of the temporomandibular joint.

Radiological Morphometric Analysis of the Mandibular Bone Structure after Ovariectomy in Mature Cynomolgus Monkeys / Oral Science International

[Purpose] The effects of experimental osteoporosis on the trabecular bone structure of the mandible in cynomolgus monkeys were examined by radiological bone morphometric analysis. [Methods] Ovariectomy (OVX) was performed on twelve 10-year-old female cynomolgus monkeys, which were fed a controlled diet for 2 years. Twelve monkeys in a sham control group were fed under the same conditions. Using a microfocus tube and computed radiography, the removed mandibular bone samples were imaged by standardized magnification radiography, and two-dimensional digital imaging data were obtained. The structural parameters, such as skeletal area, perimeter, number, complexity, continuity and anisotropy, were measured using radiological bone morphometric analysis. The bone mineral density (BMD) was measured by dual energy X-ray absorptiometry. The width of the cortical bone was measured using magnified radiographic images. [Results] There were no significant differences between the OVX and the sham control groups in the skeletal structure indicated by the skeletal volume, number, width, perimeter, complexity, continuity, separation and spacing. However, there were significant differences between the two groups in the BMD of the mandibular body, cortical bone width, anisotropy and some parameters of the skeletal continuity. Among these parameters, the difference in the thinning of the cortical bone was most significant. [Conclusions] Using two-dimensional digital radiographic image data, this study suggests that the cortical bone width is more useful than the trabecular bone structure as the morphologic parameter for diagnosis of osteoporosis in the mandibular body.

Mandibular differential premolar extraction in growing patients / 대한치과교정학회지

The extraction for orthodontic treatment can be adopted for aligning crowded dentition, improving facial esthetics and solving a skeletal discrepancy as alternative for a surgical option. Mandibular second premolar extraction was often selected as treatment plan when there are very little or no space shortage in lower arch or limited retraction of the lower incisors was required. The primary object of this study was evaluate a pretreatment condition and examine the amount of tooth movement for a mandibular second premolar extraction in growing patients. Pretreatment and posttreatment lateral cephalograms of 14 cases that had their four first premolar extracted (4/4 group), 15 cases with upper first and lower second premolar extraction (4/5 group) were selected. Structural method superimposition was conducted to evaluate a difference of dental change between 4/4 and 4/5 group. The results were as follows, 1. Pretreatment factor for 4/4 extraction or 4/5 extraction choice included maxillary incisor axis to occlusal plane, Class II molar relationship, IMPA and interincisal angle. 2. The amount of molar anterior movement in 4/5 group was greater than that of 4/4 group(p<0.05). 3. There was no significant difference between 4/4 group and 4/5 group in aspects of maxillary tooth movement(p<0.05).