Biomechanical CT for Assessment of Osteoporotic Vertebral Fracture Risk / 医用生物力学

Osteoporosis is characterized by decreased bone strength and increased fracture risk. The most serious consequence of osteoporosis is fracture, which commonly occurs in vertebrae. Accurate assessment of fracture risk at an earlier stage is the key to identify high-risk population and further prevent osteoporotic fracture. Currently, clinical assessment of vertebral fracture risk mainly relies on measurement of bone mineral density (BMD) based on dual energy X-ray absorptiometry ( DXA) or quantitative computed tomography ( QCT). However, they cannot fully reflect bone strength and resistance to fracture, and it is hard to achieve an accurate assessment. Biomechanical CT (BCT) technology, based on CT digital modeling and finite element analysis, aims at non-invasive calculation of individual bone strength, bridging the gap between biomechanics and clinical evaluation of fracture risk. In vitro mechanical experiment of vertebrae has proved that BCT is more accurate than BMD in evaluating vertebral fracture strength. Clinical studies have also shown that BCT is superior to DXA inidentifying existing fractures and predicting new fractures. In this article, the implementation process of the BCT technology was introduced, as well as critical parameters during each step affecting its result . The research progress of the BCT technique for in vitro validation and in vivo assessment of vertebral fracture risk was also summarized, with the aim to promote the application of BCT technology in clinical assessment of vertebral fracture risk for the Chinese people.

Effects of rosin diglucoside on bone metabolism in young rats / 中国药理学通报

Aim To research the effect of PDG on bone metabolism in young rats. Methods The experimental rats were randomly divided into contro group, PDG-25 group and PDG-50 group. PDG-25 group and PDG-50 group were given PDG at the dose of 25 mg·kg

Relationship between exercise and bone strength, body composition, sex hormones in postmenopausal women / 解剖学报

Objective To investigate the effects of exercise on bone strength, body composition, sex hormones and their relationship in postmenopausal women of Han nationality in Lanzhou. Methods From Jan. 2018 to Jun. 2019, 233 cases postmenopausal women of Han nationality in Lanzhou (110 cases in exercise group and 123 cases in non exercise group) were selected by stratified random sampling method, whose bone strength, body composition indexes and sex hormone were measured by ultrasonic bone mineral density meter, body composition analyzer and electrochemiluminescence automatic immune analyzer, respectively. Results There were lower body weight, body mass index and fat tissue composition of postmenopausal women of Lanzhou Han nationality (P<0.05), and there was higher bone strength, estradiol and muscle tissue composition in the exercise group (P< 0.01). The prevalence of osteoporosis and obesity was lower in the exercise group (P< 0.01). Pearson correlation analysis showed that estradiol and muscle tissue composition were positively correlated with the bone strength (P< 0.05), and it was negatively correlated with fat tissue composition in postmenopausal women (P<0.01). Logistic regression analysis showed that limb muscle mass and estradiol were protective factors for bone, and visceral fat content was the risk factor of bone abnormality in postmenopausal non-exercise women. Estrogen was the protective factor of bone in postmenopausal exercise women. Conclusion The bone strength of postmenopausal women is determined by muscle and fat tissue, and the relationship between the both is affected by exercise. Exercise could effectively prevent and control osteoporosis in postmenopausal women of Lanzhou Han nationality by promoting estrogen production, increasing limb muscle and reducing visceral fat mass.

Effect of advanced glycation end products on metabolism of bone tissue cells / 中国组织工程研究

BACKGROUND: With the research and development of bone tissue engineering, it has been found that advanced glycation end products can accumulate in bone tissue and affect the structure and biomechanical properties of bone. At present, many researchers have discovered that advanced glycation end products/receptor for advanced glycation end products can induce pathological changes of osteoblasts, osteoclasts and osteocytes through special mechanisms, thereby leading to imbalance of bone reconstruction, decrease of bone strength and increase of fracture incidence. OBJECTIVE: To review the effects of advanced glycation end products on bone biomechanics and the mechanism of advanced glycation end products/receptor for advanced glycation end products on bone tissue cells. METHODS: The first author searched the relevant articles regarding the effect of advanced glycation end products/receptor for advanced glycation end products on metabolism of bone tissue cells published in PubMed, Web of Science and Medline database from January 2005 to July 2019. The results were limited to English literatures. RESULTS AND CONCLUSION: Finally, 54 representative literatures were selected for summary. The effects of advanced glycation end products on collagen cross-linking can significantly reduce bone strength. Advanced glycation end products/receptor for advanced glycation end products affects bone metabolism through pathological mechanism changes of bone tissue cells, which results in essential changes of bone tissue cells. Finally, it will lead to imbalance of bone metabolism and increase of bone fragility. The osteoporosis is directly related to the activity change of bone tissue cells, but the specific mechanism needs further study. The change of this special mechanism may provide a unique pathological mechanism, diagnosis methods, treatment and prevention strategies for osteoporosis in the future.

Influência do sistema de criação em piso sobre cama e gaiola sobre as características ósseas e a qualidade físico-química e microbiológica de ovos de galinhas / Influence of the floor and cage creation system on the bony characteristics and the physical-chemical and microbiological quality of hen eggs

O experimento foi realizado no setor de avicultura/UFRRJ, utilizando 348 galinhas semipesadas (linhagem Dekalb Brown), com 52 semanas de idade, criadas sob dois sistemas de produção: cage-free e em gaiolas. Os dados obtidos pela análise físico-química e microbiológica dos ovos e a resistência óssea à quebra foram submetidos à análise de variância. No caso de ocorrerem efeitos dos diferentes sistemas de produção, foi aplicado o teste de Tukey a 5% de probabilidade para comparação das médias. A qualidade físico-química foi igualmente favorecida pelos dois sistemas de produção, indicando que as circunstâncias experimentais propiciaram condições adequadas para a formação de ovos de boa qualidade. O sistema de gaiola não desfavoreceu as características ósseas das galinhas, apontando que, em densidades adequadas, a gaiola pode não exercer um fator prejudicial para a qualidade óssea. O sistema de produção cage-free piorou a contaminação da casca, comprovando que ovos postos em ninhos são mais contaminados em comparação aos produzidos em gaiolas.(AU)

The experiment was carried out in the poultry sector / UFRRJ, using 348 semi-heavy hens (Dekalb Brown line), 52 weeks old, raised under two cage-free production systems and cages. The data obtained by the physical-chemical and microbiological analysis of the eggs and the bone resistance to the break were submitted to analysis of variance, in case of effects of the different production systems, the Tukey's test was applied at 5% of probability for comparison of the means. The physical-chemical quality was also favored by the two production systems, indicating that the experimental circumstances provided adequate conditions for the formation of good quality eggs. The cage system did not disfavor the bony characteristics of the hens, indicating that at suitable densities, the cage may not exert a detrimental factor to bone quality. The cage-free production system worsened shell contamination by proving that nesting eggs are more contaminated compared to those produced in cages.(AU)

Efficacy and safety of denosumab compared to bisphosphonates in improving bone strength in postmenopausal osteoporosis: a systematic review

INTRODUCTION@#Osteoporosis is the main cause of fractures among women after menopause. This study aimed to evaluate the efficacy and safety of denosumab compared to bisphosphonates in treating postmenopausal osteoporosis.@*METHODS@#Databases including PubMed and the Cochrane Central Register of Controlled Trials were systematically searched for randomised controlled trials (RCTs) that directly compared denosumab and bisphosphonates. RCTs that studied both denosumab and bisphosphonates in postmenopausal women with osteoporosis and had a Jadad score ≥ 3 were included.@*RESULTS@#Nine studies were eligible for inclusion. They were further categorised into six cohort groups. All studies had denosumab with oral bisphosphonates as the active comparator. Four out of six cohort studies showed significant improvements in bone strength (p < 0.001) at the distal radius, tibia, total hip, femoral neck, lumbar spine and trochanter at 12 months for patients on denosumab compared to the bisphosphonate group. Serum C-telopeptide of cross-linked collagen, a bone turnover marker, was consistently lower in the denosumab group in all studies. There were no significant differences in hypocalcaemia, atypical fractures, fragility fractures, osteonecrosis of the jaw, all infections (including fever or influenza-like symptoms), gastrointestinal side effects or dermatological conditions in all studies, except for one that did not document side effects.@*CONCLUSION@#Denosumab can be used both as a first-line agent and an alternative to bisphosphonate in the treatment of postmenopausal osteoporosis. There is currently insufficient data to show that denosumab is not inferior to bisphosphonates in fracture prevention.

Characteristics and relationship of bone strength and body composition in pre- And post- menopausal Dongxiang women / 解剖学报

Objective To analyze the changes of bone strength and body composition in pre- and postmenopausal Dongxiang women and explore the impact of body composition change on bone strength. Methods From Sep. 2016 to Jul. 2018, 203 cases Dongxiang 41-50 year old women (102 cases of premenopause and 101 cases of postmenopause) of Gansu Province were selected by stratified random sampling method, whose bone strength and body composition indexes were measured by ultrasonic bone mineral density meter and body composition analyzer respectively. Results There were lower bone strength and muscle tissue composition in the postmenopausal Dongxiang women (P< 0.05), and there was higher fat tissue composition (P < 0.01). The prevalence of osteoporosis was higher in postmenopausal women (P < 0. 01). Pearson correlation analysis showed that muscle tissue composition was positively correlated with the bone strength (P<0. 01), and it was negatively correlated with fat tissue composition in the pre- and postmenopausal Dongxiang women (P < 0. 0 1). Multivariate linear stepwise regression analysis showed that limb muscle mass and subcutaneous fat mass were a protective factor and a risk factor for bone strength in pre- and post-menopausal Dongxiang women, respectively. Conclusion The bone strength of Dongxiang women was determined by muscle and fat tissue, and associated with the distribution of body composition. The relationship between bone strength and body composition was not affected by menopause. Menopause was an important factor that increased the incidence of osteoporosis in Dongxiang women, and we should reinforce osteoporosis prevention in postmenopausal Dongxiang women. Strengthen physical exercise, increase limb muscle mass and reduce subcutaneous fat could contribute to increase bone strength and prevent osteoporosis in in the pre- and post-menopausal Dongxiang women.

Zoledronic acid effect on bone of growing rats / Efecto del ácido zoledrónico en el hueso de ratas en crecimiento

Zoledronic acid (ZA) is an antiresorptive drug used in children with bone diseases like osteogenesis imperfecta, juvenil osteoporosis, fibrous dysplasia and primary bone tumors. The aim of the present study was to evaluate the effects of ZA dose accumulation on growing bone during different periods of treatment in normal rats. Methods: A 4x2 factorial design was used to study the effect of the dose of ZA (D: 0-2.5-12.5-25 µg Z/kg body weight/s.c. weekly) and the length of treatment (T: 15-30 days) in normal female Sprague Dawley rats. Bone morphometric, histomorphometric, densitometric and biomechanical studies were performed. Results: Femoral length and cross-sectional area were affected by both D and T. A significant interaction between D and T was observed in length with a lower value at higher dose and 30 days of treatment. Growth plate of the tibia showed a decrease in total thickness with D and T. Histomorphometric and connectivity parameters of trabecular bone were significantly increased with D and several parameters were also affected by T. Cortical bone strength was increased only with T. Biomechanical parameters of trabecular bone showed significant interaction with greater effect at higher D and T. Conclusion: Even though a mild negative effect of the highest dose of ZA on linear and appositional growth was observed, the other bone parameters evaluated were improved. A careful risk/benefit analysis would lead us to conclude that the mild deleterious effects of ZA during growth are outweighed by the benefit obtained with treatment. (AU)

El ácido zoledrónico (AZ) es un fármaco antirresortivo utilizado en niños con enfermedades óseas como osteogénesis imperfecta, osteoporosis juvenil, displasia fibrosa y tumores óseos primarios. El objetivo del presente estudio fue evaluar los efectos de las dosis acumuladas de AZ en el hueso en crecimiento de ratas hembras normales durante diferentes períodos de tratamiento. Métodos: se utilizó un diseño factorial de 4x2 para estudiar el efecto de la dosis de AZ (D: 0-2,5-12,5-25 µg Z / kg de peso corporal /sc semanalmente) y el período de tratamiento (T: 15-30 días) en ratas Sprague Dawley. Se realizaron estudios óseos morfométricos, histomorfométricos, densitométricos y biomecánicos. Resultados: la longitud y el área de sección transversal del fémur se vieron afectadas tanto por D como por T. Se observó una interacción significativa entre D y T en la longitud obteniéndose un valor más bajo a la dosis más alta y a 30 días de tratamiento. El cartílago de crecimiento de la tibia mostró una disminución en el espesor total con D y T. Los parámetros histomorfométricos y de conectividad del hueso trabecular aumentaron significativamente con D y varios parámetros también se vieron afectados por T. La fortaleza ósea cortical aumentó solo con T. Los parámetros biomecánicos del hueso trabecular mostraron una interacción significativa con un mayor efecto a mayor D y T. Conclusión: a pesar que se observó un leve efecto negativo de la dosis más alta de AZ sobre el crecimiento lineal y aposicional, el resto de los parámetros óseos evaluados mejoraron. Un análisis cuidadoso del riesgo /beneficio permite concluir que los efectos negativos leves del AZ durante el crecimiento son superados por el beneficio obtenido con el tratamiento. (AU)

Decreased levels of vitamin D3 and supplementation with 1,25-dihydroxyvitamin D3-glycoside on performance, carcass yield and bone quality in broilers / Diminuição dos níveis de vitamina D3 e suplementação com 1,25-dihidroxivitamina D3 glicosídeo sobre o desempenho, o rendimento da carcaça e a qualidade dos ossos em frangos de corte

ABSTRACT: An experiment was performed to evaluate the effect of decreased levels of vitamin D3 in the premix and 1,25-dyhydroxyvitamin D3-glycoside (1,25(OH)2D3-glycoside) supplementation on performance, carcass yield and bone quality in 42d old broilers. Seven-d-old male chickens Cobb500® were distributed in a randomized design with six treatments: a control diet with inclusion of vitamin D3 in the premix, without supplementation of 1,25(OH)2D3-glycoside, and five diets with decreased levels of vitamin D3 (100%, 75%, 50%, 25% and 0% about the control) plus the addition of 1,25(OH)2D3-glycoside, 50g ton-1 of diet. The main results were to reduce the tenor of Vitamin D3 in the premix when the addition of 1,25(OH)2D3-glycoside did not affect (P>0.05) the performance, carcass yield and bone quality variables. However, performance (feed intake, gain weight, feed conversion), yield (warm carcass weight) and bone quality (dry weight, length, mineral matter and breaking strength) of broilers fed with diets without vitamin D3 in the premix and with addition of 1,25(OH)2D3-glycoside, which was the single source of vitamin D, had as a result very low (P<0.05) values comparing to the control. For the purposes of the present research, it was concluded that is possible the reduction of vitamin D3 tenor in the premix up to 75% when the diet of male broilers is supplemented with 1,25(OH)2D3-glycoside. However, the use of 1,25(OH)2D3-glycoside as a single source of vitamin D, as tested here, is not recommended for broilers diets.

RESUMO: Um experimento foi realizado para avaliar o efeito da diminuição dos níveis de vitamina D3 no premix e a suplementação de 1,25-dihidroxivitamina D3-glicosídeo (1,25(OH)2D3-glicosídeo) sobre o desempenho, rendimento de carcaça e qualidade óssea em frangos de corte de 42 dias. Machos Cobb500® de sete dias de idade foram distribuídos em delineamento inteiramente casualizado com seis tratamentos: uma dieta controle com inclusão de vitamina D3 no premix, sem suplementação de 1,25(OH)2D3-glicosídeo, e cinco dietas com níveis decrescentes de vitamina D3 (100%, 75%, 50%, 25% e 0% em relação ao controle) mais a adição de 1,25(OH)2D3-glicosídeo (50g ton-1 de dieta). Entre os principais resultados, foi observado que a redução do teor de vitamina D3 no premix quando adicionado 1,25(OH)2D3-glicosídeo não afetou (P>0,05) o desempenho, o rendimento da carcaça e as variáveis da qualidade óssea. No entanto, as variáveis do desempenho e o rendimento (consumo de ração, ganho de peso, conversão alimentar, peso da carcaça quente) e da qualidade dos ossos (peso seco, comprimento, matéria mineral e resistência à ruptura) de frangos alimentados com dietas sem vitamina D3 no premix, com a adição de 1,25(OH)2D3-glicosídeo como a única fonte de vitamina D, teve como resultado valores muito baixos (P<0,05) em comparação ao controle. Para os propósitos da presente pesquisa, concluiu-se que é possível a redução do teor de vitamina D3 no premix até 75% quando a dieta de frangos de corte machos é suplementada com 1,25(OH)2D3-glicosídeo. No entanto, o uso de 1,25(OH)2D3-glicosídeo como única fonte de vitamina D, conforme testado aqui, não é recomendado para dietas de frangos de corte.

Review of high-resolution peripheral quantitative computed tomography for the assessment of bone microstructure and strength / 生物医学工程学杂志

Trabecular microstructure is an important factor in determining bone strength and physiological function. Normal X-ray and computed tomography (CT) cannot accurately reflect the microstructure of trabecular bone. High-resolution peripheral quantitative computed tomography (HR-pQCT) is a new imaging technique in recent years. It can qualitatively and quantitatively measure the three-dimensional microstructure and volume bone mineral density of trabecular bone . It has high precision and relative low dose of radiation. This new imaging tool is helpful for us to understand the trabecular microstructure more deeply. The finite element analysis of HR-pQCT data can be used to predict the bone strength accurately. We can assess the risk of osteoporosis and fracture with three-dimensional reconstructed images and trabecular microstructure parameters. In this review, we summarize the technical flow, data parameters and clinical application of HR-pQCT in order to provide some reference for the popularization and extensive application of HR-pQCT.

Bone characteristics of pigs fed different sources of phosphorus / Características óseas de cerdos alimentados con diferentes fuentes de fósforo / Características ósseas de suínos alimentados com diferentes fontes de fósforo

Summary Background: phosphorus supplementation should help to keep bone integrity and prevent fractures during the development and slaughter of animals. Objective: to evaluate the effect of different phosphorus sources on one characteristics of pigs. Methods: one-hundred and twelve piglets (28.65 ± 2.82 Kg body weight) were distributed into an 8×2 factorial arrangement (eight sources of phosphorus × two sexes) in blocks in a completely randomized design. The diets were formulated on a total-phosphorus basis, with 0.32 and 0.31% of P for the control diet and 0.56 and 0.42% of P for the other treatments in the growth and finishing phases, respectively. Phosphorus was supplemented as dicalcium phosphate (DCP); mono-dicalcium phosphate (MDCP); triple superphosphate (TSP); single superphosphate (SSP); Catalão-rock phosphate (ROCK); a mixture of sources (MIX); phosphoric acid (PPA); and the control diet (CTR). Results: there was no interaction between phosphorus sources and sex in any of the parameters. Thickness of the compact tissue was the lowest in the CTR, differing from the diets containing DCP, MDCP, and PPA, followed by diets SSP, TSP, and ROCK, with the greatest value for MDCP. Porosity of the compact tissue was higher for the CTR and SSP diets. Conclusion: the use of less elaborate sources of phosphorus, such as rock phosphate and single superphosphate, was less effective than the other sources to improve bone integrity of pigs.

Resumen Antecedentes: la suplementación dietaria con fósforo ayuda a mantener la integridad del hueso y prevenir fracturas durante el desarrollo y sacrificio de los animales. Objetivo: evaluar el efecto de diferentes fuentes de fósforo sobre las características óseas de los cerdos. Métodos: ciento doce lechones (peso corporal: 28,65 ± 2,82 Kg) se distribuyeron en un arreglo factorial 8×2 (ocho fuentes de fósforo × dos sexos) en bloques al azar. Las dietas se formularon con base en fósforo total, con 0,32 y 0,31% de P para la dieta control y 0,56 y 0,42% de P para los otros tratamientos en las fases de crecimiento y finalización, respectivamente. El fósforo se suplementó como fosfato dicálcico (DCP), monofosfato dicálcico (MDCP), superfosfato triple (TSP), superfosfato simple (SSP), fosfato de roca Catalão (ROCK), mezcla de fuentes (MIX), ácido fosfórico (PPA) y dieta control (CTR). Resultados: no se observó interacción entre las fuentes de fósforo y el sexo en ninguno de los parámetros estudiados. El espesor del tejido compacto fue más bajo en el CTR, y diferente a las dietas que contenían DCP, MDCP y PPA, seguido por las dietas SSP, TSP y ROCK; con el mayor valor para MDCP. La porosidad del tejido compacto fue mayor para las dietas CTR y SSP. Conclusión: el uso de fuentes menos elaboradas de fósforo, tales como el fosfato de roca y superfosfato simple, fue menos efectivo que las otras fuentes en mejorar la integridad ósea de los cerdos.

Resumo Antecedentes: a suplementação de fósforo deve manter a integridade do tecido ósseo e prevenir fraturas durante o desenvolvimento e abate dos animais. Objetivo: avaliar o efeito de diferentes fontes de fósforo sobre as características ósseas dos suínos. Métodos: cento e doze leitões com peso médio inicial de 28,65 ± 2,82 Kg foram distribuídos em esquema fatorial 8×2 (oito fontes de fósforo × dois sexos) em blocos casualizados. As dietas foram formuladas baseadas em fósforo total com 0,32 e 0,31% de P para a dieta controle e com 0,56 e 0,42% de P para os outros tratamentos nas fases de crescimento e terminação, respectivamente. O fósforo nas dietas foi suplementado com fosfato bicálcico (DCP); mono-fosfato bicálcico (MDCP); superfosfato triplo (TSP); superfosfato simples (SSP); fosfato de rocha Catalão (ROCK); uma mistura de fontes (MIX); ácido fosfórico (PPA); e a dieta controle (CTR). Resultados: não houve interação entre as fontes de fósforo e sexo dos animais para qualquer um dos parâmetros estudados. A espessura do tecido compacto é menor na CTR, diferenciando-se das dietas DCP, MDCP e PPA, seguido pelas dietas SSP, TSP e ROCK, sendo que o maior valor foi observado na dieta com MDCP. A porosidade do tecido compacto foi maior com as dietas CTR e SSP. Conclusão: o uso de fontes menos elaboradas de fósforo como superfosfato simples e fosfato de rocha foram menos eficientes do que os outros tratamentos para melhorar a integridade óssea de suínos.

Biomecánica de las fracturas por stress / Biomechanical features of stress fractures

Se define como estrés (stress) tanto la fuerza que una carga externa ejerce sobre un cuerpo sólido como la fuerza reactiva que acompaña a la primera (Ley de Newton), por unidad de área imaginaria transversal a su dirección. Las cargas internas reactivas inducen deformaciones proporcionales del cuerpo. La resistencia del cuerpo a deformarse se llama rigidez. La deformación puede resquebrajar el cuerpo y, eventualmente, producir una fractura por confluencia de trazos. La resistencia del cuerpo a separarse en fragmentos por esa causa se llama tenacidad. La resistencia del cuerpo a la fractura es proporcional al stress que puede soportar sin separarse en fragmentos por deformación (no hay fractura sin deformación y sin stress previo). El stress máximo que un cuerpo puede soportar sin fracturarse resulta de una combinación de ambas propiedades: rigidez y tenacidad, cada una con distintos determinantes biológicos. Una o varias deformaciones del cuerpo pueden provocarle resquebrajaduras sin fracturarlo. La acumulación de resquebrajaduras determina la "fatiga" del material constitutivo del cuerpo, que reduce su rigidez, tenacidad y resistencia a la fractura para la próxima ocasión ("fragilidad por fatiga"). En el caso de los huesos, en general, los términos stress y fatiga tienen las connotaciones amplias referidas, respecto de todas las fracturas posibles. La fatiga predispone a fracturas a cargas bajas, que se denominan (correctamente) "fracturas por fatiga" y también (incorrectamente) "fracturas por stress", para distinguirlas de las que ocurren corrientemente, sin resquebrajaduras previas al trauma, que se denominan (incorrectamente) "fracturas por fragilidad, o por insuficiencia". En realidad, todas las fracturas se producen por stress y por fragilidad o insuficiencia (en conjunto); pero la distinción grosera entre fracturas "por fatiga, o por stress", por un lado, y "por fragilidad" o "por insuficiencia", por otro, aceptando las amplias connotaciones referidas antes, tiene valor en la práctica clínica. Este artículo intenta explicar esas particularidades biomecánicas y describir las distintas condiciones que predisponen a las fracturas "por fatiga o por stress" en la clínica, distinguiéndolas de las fracturas "por fragilidad o por insuficiencia" (manteniendo estas denominaciones) y detallando las características de interés directo para su diagnóstico y tratamiento. (AU)

The term "stress" expresses the force exerted by an external load on a solid body and the accompanying, opposed force (Newton's Law), expressed per unit of an imaginary area perpendicular to the loading direction. The internal loads generated this way deform (strain) proportionally the body's structure. The resistance of the body to strain expresses its stiffness. Critical strain magnitudes may induce micro-fractures (microdamage), the confluence of which may fracture the body. The body's resistance to separation into fragments determines its toughness. Hence, the body's resistance to fracture is proportional to the stress the body can support (or give back) while it is not fractured by the loadinduced strain (no stress, no strain -> no fracture). Therefore, the maximal stress the body can stand prior to fracture is determined by a combination of both, its stiffness and its toughness; and each of those properties is differently determined biologically. One or more deformations of the body may induce some microdamage but not a fracture. Microdamage accumulation determines the fatigue of the material constitutive of the body and reduces body's toughness, leading to a "fatigue-induced fragility". In case of bones, in general, both stress and fatigue have the referred, wide connotations, regarding any kind of fractures. In particular, bone fatigue predisposes to low-stress fractures, which are named (correctly) "fatigue fractures" and also misnamed "stress fractures", to distinguish them from the current fractures that occur without any excess of microdamage, that are named (wrongly) "fragility" or "insufficiency" fractures. In fact, all fractures result from all stress and fragility or insufficiency as a whole; however, the gross distinction between "fatigue or stress fractures", on one side, and "fragility or insufficiency fractures", on the other, accepting the wide connotations of the corresponding terminology, is relevant to clinical practice. This article aims to explain the above biomechanical features and describe the different instances that predispose to "fatigue or stress fractures" in clinical practice, as a different entity from "insufficiency or fragility fractures" (maintaining this nomenclature), and describe their relevant features to their diagnosis and therapy. (AU)

The Association of Higher Plasma Macrophage Migration Inhibitory Factor Levels with Lower Bone Mineral Density and Higher Bone Turnover Rate in Postmenopausal Women

BACKGROUND: Despite evidence from animal and clinical studies showing the detrimental effects of macrophage migration inhibitory factor (MIF) on bone metabolism, there are no clinical studies relating circulating MIF levels to osteoporosis-related phenotypes. This cross-sectional study investigated the association of plasma MIF with bone mineral density (BMD), bone turnover markers (BTMs), and prevalence of osteoporosis in postmenopausal Korean women. METHODS: A total of 246 women not taking any medications or diagnosed with any diseases that could affect bone metabolism were enrolled. BMD values at the lumbar spine, femoral neck, and total femur, and blood levels of MIF and BTMs were measured in all subjects. Osteoporosis was defined by World Health Organization criteria. RESULTS: Before and after adjustment for confounding variables, higher MIF levels were significantly associated with lower BMD values at all measured sites and higher levels of all BTMs. All BMD values and BTMs significantly changed in a dose-dependent fashion across increasing MIF quartile. When participants were divided into two groups according to osteoporosis status, postmenopausal women with osteoporosis demonstrated 24.2% higher plasma MIF levels than those without osteoporosis (P=0.041). The odds ratio per each standard deviation increment of MIF levels for prevalent osteoporosis was 1.32 (95% confidence interval, 1.01 to 1.73). CONCLUSION: This study provides the first epidemiological evidence that higher plasma MIF may be associated with higher risk of osteoporosis resulting from lower bone mass and higher bone turnover rate, and thus it could be a potential biomarker of poor bone health outcomes in postmenopausal women.

Combined treatment with minodronate and vitamin C increases bone mineral density and strength in vitamin C-deficient rats

OBJECTIVES: Reduced bone quality caused by vitamin C deficiency in older persons may lead to incidental fragility fractures during bisphosphonate treatment, although bisphosphonate increases bone mineral density (BMD). This study aimed to evaluate the effects of minodronate and ascorbic acid (Aa) on BMD, bone quality, and bone strength in Aa(-)deficient osteogenic disorder Shionogi (ODS) rats. METHODS: Six-month-old ODS rats were divided into four groups (n = 20 per group): (1) Aa supplementation (Aa(+)); (2) Aa(-)deficient (Aa(-)); (3) Aa supplementation and minodronate administration (Aa(+) + Mino); and (4) Aa(-)deficient and minodronate administration (Aa(-) + Mino). BMD, bone strength, bone histomorphometry, and bone quality determined using Fourier transform infrared spectroscopy imaging (FTIRI) were evaluated after 4 and 8 weeks. RESULTS: BMD was significantly higher in the Aa(+) + Mino group than in the Aa(-) group (p < 0.05). Bone strength was significantly higher in the Aa(+) and Aa(+) + Mino groups than in the Aa(-) group (p < 0.05). Furthermore, bone strength was significantly higher in the Aa(+) + Mino group than in the Aa(-) + Mino group (p < 0.05). Minodronate treatment irrespective of Aa supplementation significantly decreased bone resorption compared with the Aa(+) and Aa(-) groups (p < 0.05). No significant differences in the parameters evaluated by FTIRI were observed between the groups. CONCLUSIONS: Aa supplementation improved bone strength in ODS rats. Combined treatment with minodronate and Aa, but not minodronate alone, improved bone strength and increased BMD. Aa is required for bone health because it is essential for osteoblast differentiation.

Efeitos do desuso e da deficiência de estrógeno sobre a microarquitetura óssea e suas propriedades biomecânicas / Effects of disuse and estrogen deficiency on bone microarchitecture and its biomechanical properties

O objetivo desse estudo foi analisar se há diferenças no efeito do desuso e da deficiência de estrógeno sobre o tecido ósseo trabecular e cortical, e se estes efeitos influenciam na qualidade do tecido ósseo aumentando sua fragilidade. Para este estudo, 30 ratas Wistar com 19 semanas de idade foram distribuídas nos grupos: controle (CON), descarregamento dos membros posteriores (HLU) e ovariectomizado (OVX). As análises da densidade óssea in vivo (DXA) dos fêmures e tíbias e as dosagens plasmáticas de cálcio, fósforo, fosfatase alcalina, TRAP (espectrofotometria) e E2 (ELISA) foram realizadas no início e fim do experimento, com 19 e 27 semanas de idade respectivamente. Na 27a semana, os fêmures e as tíbias foram desarticulados e armazenados para avaliar a microestrutura do osso trabecular e cortical (microtomografia computadorizada), além das propriedades biomecânicas do colo femoral e da diáfise femoral e tibial (ensaio mecânico). O grupo HLU apresentou diminuição na concentração plasmática de cálcio e atividade da fosfatase alcalina total, diminuição na DMOa do fêmur com aumento na porosidade cortical e diminuição na resistência óssea, entretanto, não foram observadas estas alterações na tíbia. O grupo OVX apresentou diminuição nas concentrações plasmáticas de cálcio, diminuição da DMOa do fêmur, deterioração trabecular no fêmur e na tíbia, com maior deterioração nas trabéculas ósseas tibiais, sem alteração na resistência óssea em ambos os ossos. Esses resultados demonstram que apesar do grupo HLU e OVX apresentassem alterações na densidade mineral óssea e microarquitetura óssea, podemos concluir que o desuso determinou maior perda no tecido cortical e na resistência óssea em relação à deficiência de estrógeno. Portanto, as análises da estrutura do tecido cortical, como a porosidade cortical, podem ser preponderantes para prever o risco de fratura.

The objective of this study was to analyze whether there are differences in the effect of disuse and estrogen deficiency on trabecular and cortical bone tissue, and whether these effects influence the quality of bone tissue increasing its fragility. For this study, 30 Wistar rats with 19 weeks old, were divided into groups: control (CON), hindlimb unloading (HLU) and ovariectomy (OVX). In vivo analysis of bone density (DXA) from femurs and tibias and plasma levels of calcium, phosphorus, alkaline phosphatase, TRAP (spectrophotometry) and E2 (ELISA) were performed at the beginning and end of the experiment, and 19 age 27 weeks, respectively. In the 27th week, the femur and tibia were disjointed and stored to assess the microstructure of trabecular and cortical bone (microcomputed tomography) and biomechanical properties of the femoral neck and femoral shaft and tibial (mechanical tests). The HLU group showed a decrease in plasma calcium concentration and total alkaline phosphatase activity, decreased femoral BMAD with increased cortical porosity and decrease in bone strength, however, there were no such changes in the tibia. The OVX group showed a decrease in plasma concentrations of calcium, decreased femoral BMAD, trabecular deterioration in the femur and tibia, with further deterioration in the tibial trabecular bone, with no change in bone strength in both bones. These results demonstrate that although the HLU and OVX group showed changes in bone mineral density and bone microarchitecture, we can conclude that the in disuse determined higher cortical tissue loss and bone strength relative to estrogen deficiency. Therefore, the analysis of the cortical tissue structure, such as cortical porosity can be prevalent to predict fracture risk.

Effects of electro-acupuncture on Jiaji acupoints combined with treadmill training on tibia bone mass of rabbit with sciatic nerve injury / 中华物理医学与康复杂志

Objective To observe the effects of electro-acupuncture on Jiaji acupoints combine with treadmill training on tibia bone mass of rabbits with sciatic nerve injury,so as to provide the theoretical support for better project to maintain normal metabolism of bone after peripheral nerve injury.Methods A total of 24 New Zealand rabbits were randomly divided into four groups (n =6),namely a model group,a sham group,a treadmill group and an electro-acupuncture + treadmill group according to a random number table.The sciatic nerve of rabbits in the model,treadmill and electro-acupuncture + treadmill group was clamped using hemostatic forceps to establish the model of sciatic nerve injury,while that of the sham group was not clamped,just cut soft tissue around the sciatic nerve.Three days after modeling,the rabbits in treadmill group and the electro-acupuncture + treadmill group were given treadmill training and electro-acupuncture combine with treadmill training respectively,lasting 4 months,whereas those in the sham and the model groups were not given any intervention.Right after modeling,the behavior of rabbits in four groups was observed.Four weeks after treatment or feeding,their bone mineral density and bone strength of tibia were measured.Results Four weeks after treatment,there was significant reduction in bone density and bone strength of tibia in the model,the treadmill and the electro-acupuncture + treadmill groups compared with those in the sham group(P ＜ 0.05) ; the bone mineral density and bone strength of tibia in the electro-acupuncture + treadmill group were 0.17 ± 0.01 g/cm2 and 161.92 ± 43.27 N respectively,significantly higher than those in both the model and the treadmill groups (P ＜ 0.05).Conclusion Electro-acupuncture combined with treadmill training can improve tibia bone mineral density and bone strength after sciatic nerve injury and facilitate the normal metabolism of the bone and to maintain its normal function.

A study on the compatibility between one-bottle dentin adhesives and composite resins using micro-shear bond strength

OBJECTIVES: This study was performed to determine whether the combined use of one-bottle self-etch adhesives and composite resins from same manufacturers have better bond strengths than combinations of adhesive and resins from different manufacturers. MATERIALS AND METHODS: 25 experimental micro-shear bond test groups were made from combinations of five dentin adhesives and five composite resins with extracted human molars stored in saline for 24 hr. Testing was performed using the wire-loop method and a universal testing machine. Bond strength data was statistically analyzed using two way analysis of variance (ANOVA) and Tukey's post hoc test. RESULTS: Two way ANOVA revealed significant differences for the factors of dentin adhesives and composite resins, and significant interaction effect (p < 0.001). All combinations with Xeno V (Dentsply De Trey) and Clearfil S3 Bond (Kuraray Dental) adhesives showed no significant differences in micro-shear bond strength, but other adhesives showed significant differences depending on the composite resin (p < 0.05). Contrary to the other adhesives, Xeno V and BondForce (Tokuyama Dental) had higher bond strengths with the same manufacturer's composite resin than other manufacturer's composite resin. CONCLUSIONS: Not all combinations of adhesive and composite resin by same manufacturers failed to show significantly higher bond strengths than mixed manufacturer combinations.

Analysis of Trabecular Bone Strength using Finite Element Analysis / 대한골다공증학회지

OBJECTIVES: The purpose of this study is to develop a method of evaluation based on finite element analysis (FEA) using micro-CT images for the measurement of trabecular bone strength. METHODS: The primary compressive trabeculae were obtained from the human femoral head of three cadavers (21 year old male (M/21), 51 year old male (M/51), 51 year old female (F/51). All bone specimens were scanned using micro-CT at 24.9microm of spatial resolution under 70 kV's voltage and current of 141microA. The percent bone volume was calculated from the CTAn (SKYSCAN, Belgium) software, it's represented the bone mineral density (BMD). After scanning, the finite element model was reconstructed based on micro-CT images. All models were applied to be linear elastic, isotropic, and uniform with a tissue modulus of 5.17 GPa and a tissue Poisson's ratio of 0.3. RESULTS: The percent bone volume(%) were 31.819 (+/-0.648), 21.513 (+/-2.489), 20.280 (+/-1.891) and Bone strength (MPa) were 187.741 (+/-13.006), 61.585 (+/-11.094), 61.266 (+/-16.744) in M/20, M/51 and F/51. The trabecular bone strength of the primary compressive trabeculae in M/20 was 3 times more than the trabecular bone strength in M/51 and F/51. The percent bone volume in M/20 was 148% and 157% higher than the percent bone volume in M/51 and F/51. CONCLUSIONS: The finite element analysis is more sensitive than the percent bone volume in reflecting the morphometry index of primary compressive trabeculae. The high resolution FEA reconstructed from high resolution MRI or high resolution CT may improve the evaluation of trabecular bone strength in the medical field.

Bone Strength of the Primary Compression Trabeculae in Human Calcaneus / 대한골다공증학회지

OBJECTIVES: The accuracy of bone strength can be improved for medically treating osteoporosis by diagnosing and predicting fracture risk. In this study, we calculated the material properties of calcaneus bone and evaluated the statistical correlation of the bone mineral density (BMD) with morphometry indices and bone strength. MATERIALS & METHODS: Twelve cored bone samples were obtained from the primary compressive trabeculae of human calcaneus. All samples were scanned with a Lunar PIXImus(R), and two-dimensional serial section images were obtained on a micro-computed tomography system. A mechanical test was performed with an Instron universal testing machine and finite element analysis (FEA) to determine material properties and bone strength. RESULTS: The material property of the samples was 2.97 GPA. BMD was significantly correlated with bone strength and morphometric indices except for Tb.Sp, DA, and Tb.N. The statistical relationship between bone strength and the morphometric indices was significant except for DA. CONCLUSIONS: FEA based on in vivo high resolution serial section images can be used to directly evaluate bone strength and will be a useful tool in clinical practice for diagnosing osteoporosis and predicting fracture risk.