Properties Of Long Bones Research Articles

Comprehensively characterizing heterogeneous and transversely isotropic properties of femur cortical bones

Comprehensive characterization of the transversely isotropic mechanical properties of long bones along both the longitudinal and circumferential gradients is crucial for developing accurate mathematical models and studying bone biomechanics. In addition, mechanical testing to derive elastic, plastic, and failure properties of bones is essential for modeling plastic deformation and failure of bones. To achieve these, we machined a total of 336 cortical specimens, including 168 transverse and 168 longitudinal specimens, from four different quadrants of seven different sections of 3 bovine femurs. We conducted three-point bending tests of these specimens at a loading rate of 0.02 mm/s. Young’s modulus, yield stress, tangential modulus, and effective plastic strain for each specimen were derived from correction equations based on classical beam theory. Our statistical analysis reveals that the longitudinal gradient has a significant effect on the Young’s modulus, yield stress, and tangential modulus of both longitudinal and transverse specimens, whereas the circumferential gradient significantly influences the Young’s modulus, yield stress, and tangential modulus of transverse specimens only. The differences in Young’s modulus and yield stress between longitudinal specimens from different sections are greater than 40%, whereas those between transverse specimens are approximately 30%. The Young’s modulus and yield stress of transverse specimens in the anterior quadrant were 18.81%/15.46% and 18.34%/14.88% higher than those in the posterior and lateral quadrants, respectively. There is no significant interaction between the longitudinal gradient and the circumferential gradient. Considering the transverse isotropy, it is crucial to consider loading direction when investigating the impact of circumferential gradients in the anterior, lateral, medial, and posterior directions. Our findings indicate that the conventional assumption of homogeneity in simulating the cortical bone of long bones may have limitations, and researchers should consider the anatomical position and loading direction of femur specimens for precise prediction of mechanical responses.

Treatment with PB125® Increases Femoral Long Bone Strength in 15-Month-Old Female Hartley Guinea Pigs.

Nuclear factor-erythroid 2-related factor-2 (Nrf2) is a transcription factor that serves as a master regulator of anti-inflammatory agents, phase I xenobiotic, and phase II antioxidant enzymes, all of which provide a cytoprotective role during disease progression. We hypothesized that oral administration of a purported phytochemical Nrf2-activator, PB125®, would increase long bone strength in aging Hartley guinea pigs, a model prone to musculoskeletal decline. Male (N = 56) and female (N = 56) guinea pigs were randomly assigned to receive daily oral treatment with either PB125® or vehicle control. Animals were treated for a consecutive 3-months (starting at 2-months of age) or 10-months (starting at 5-months of age) and sacrificed at 5-months or 15-months of age, respectively. Outcome measures included: (1) ANY-maze™ enclosure monitoring, (2) quantitative microcomputed tomography, and (3) biomechanical testing. Treatment with PB125® for 10months resulted in increased long bone strength as determined by ultimate bending stress in female Hartley guinea pigs. In control groups, increasing age resulted in significant effects on geometric and structural properties of long bones, as well as a trending increase in ultimate bending stress. Furthermore, both age and sex had a significant effect on the geometric properties of both cortical and trabecular bone. Collectively, this work suggests that this nutraceutical may serve as a promising target and preventive measure in managing the decline in bone mass and quality documented in aging patients. Auxiliary to this main goal, this work also capitalized upon 5 and 15-month-old male and female animals in the control group to characterize age- and sex-specific differences on long bone geometric, structural, and material properties in this animal model.

Dietary supplementation with nacre reduces cortical bone loss in aged female mice

Aging is associated with detrimental bone loss leading to fragility fractures in both men and women. Notably, a majority of bone loss with aging is cortical, as well as a large number of fractures are non-vertebral and at the non-hip sites. Nacre is a product of mollusks composed of calcium carbonate embedded in organic components. As our previous study demonstrated the protective effect of nacre supplementation on trabecular bone loss in ovariectomized rats, we sought to evaluate the effect of dietary nacre on bone loss related to aging in female mice which do not suffer true menopause as observed in women. The current study compared the effect of a 90-day long nacre-supplemented diet to that of Standard or CaCO3 diets on both bone mass and strength in 16-month-old C57BL/6 female mice. Multiple approaches were performed to assess the microarchitecture and mechanical properties of long bones, analyze trabecular histomorphometry, and measure bone cell-related gene expressions, and bone turnover markers. In the cortex, dietary nacre improved cortical bone strength in line with lower expression levels of genes reflecting osteoclasts activity compared to Standard or CaCO3 diets (p < 0.05). In the trabeculae, nacre-fed mice were characterized by a bone remodeling process more active than the other groups as shown by greater histomorphometric parameters and osteoblast-related gene expressions (p < 0.05). But these differences were not exhibited at the level of the trabecular microarchitecture at this age. Collectively, these data suggest that dietary nacre should be a potential candidate for reducing aging-associated cortical bone loss in the elderly.

Hind limb muscles influence the architectural properties of long bones in frogs.

The Mechanostat Theory states that osteocytes sense both the intensity and directionality of the strains induced by mechanical usage and modulate the bone design accordingly. In long bones, this process may adapt anterior-posterior and lateral-medial strength to their mechanical environment showing regional specificity. Anuran species are ideal for analyzing the muscle-bone relationships related to the different mechanical stresses induced by their many locomotor modes and habitat uses. This work aimed to explore the relationships between indicators of the force of the most relevant muscles to locomotion and the mechanical properties of femur and tibia fibula in preserved samples of three anuran species with different habitat use (aquatic, arboreal) and locomotion modes (swimmer, jumper, walker/climber). For that purpose, we measured the anatomical cross-sectional area of each dissected muscle and correlated it with the moments of inertia and bone strength indices. Significant, species-specific covariations between muscle and bone parameters were observed. Pseudis platensis, the aquatic swimmer, showed the largest muscles, followed by Boana faber, the jumper and Phyllomedusa sauvagii, the walker/climber. As we expected, bigger muscles correlate with bone parameters in all the species. Nevertheless, smaller muscles also play an important role in bone design. In aquatic species, muscle interaction enhances mostly lateral bending strength throughout the femur and lateral and antero-posterior bending strength in the tibia fibula. In the jumper species, muscles affected the femur and tibia fibula mostly in anterior-posterior bending. In the walker/climber species, responses involving both antero-posterior and lateral bending strengths were observed in the femur and tibia fibula. These results show that bones will be more or less resistant to lateral and antero-posterior bending according to the different mechanical challenges of locomotion in aquatic vs. arboreal habitats. This study provides new evidence of the muscle-bone relationships in three frog species associated with their different locomotion and habitat uses, highlighting the crucial role of muscle in determining the architectural properties of bones.

Age-Related Study and Collision Response of Material Properties of Long Bones in Chinese Pedestrian Lower Limbs

In forensic examination cases, lower limb injuries are common, and pedestrians of different ages suffer different injuries when they are hit by vehicles, especially the injuries to the long bones of the lower limbs. Aging remains a challenging issue for the material properties and injury biomechanical properties of pedestrian lower limb long bones. We analyzed the regression relationship between the age of 50 Chinese pedestrians and the material properties of the lower limb long bones (femur, tibia). We compared them with previous studies to propose a regression model suitable for Chinese human long bone material properties. Through the established Human Active Lower Limb (HALL) model that conforms to the Chinese human anatomy, seven pedestrians’ (20/30/40/50/60/70/80 years old (YO)) lower limbs were parameterized to assign long bone material properties. In the finite element analysis, the Hall model was side-impacted by a family car (FCR) at speeds of 30/40/50/60/70 km/h, respectively. The results showed that an increase in age was negatively correlated with a decrease in the material properties of each long bone. Moreover, with an increase in age, the tolerance limit of long bones gradually decreases, but there will be a limit, and there is no obvious positive correlation with age. During a standing side impact, the stress change in the femur was significantly smaller than that of the tibia, and the stress of the femur and tibia decreased with age. Age is a more significant influencing factor for lower limb injuries. Older pedestrians have a higher risk of lower limb injuries. Forensic experts should pay attention to the critical factor of age when encountering lower limb traffic accident injuries in forensic identification work.

Variation in cross-sectional indicator of femoral robusticity in Homo sapiens and Neandertals

Variations in the cross-sectional properties of long bones are used to reconstruct the activity of human groups and differences in their respective habitual behaviors. Knowledge of what factors influence bone structure in Homo sapiens and Neandertals is still insufficient thus, this study investigated which biological and environmental variables influence variations in the femoral robusticity indicator of these two species. The sample consisted of 13 adult Neandertals from the Middle Paleolithic and 1959 adult individuals of H. sapiens ranging chronologically from the Upper Paleolithic to recent times. The femoral biomechanical properties were derived from the European data set, the subject literature, and new CT scans. The material was tested using a Mantel test and statistical models. In the models, the polar moment of area (J) was the dependent variable; sex, age, chronological period, type of lifestyle, percentage of the cortical area (%CA), the ratio of second moment areas of inertia about the X and Y axes (Ix/Iy), and maximum slope of the terrain were independent covariates. The Mantel tests revealed spatial autocorrelation of the femoral index in H. sapiens but not in Neandertals. A generalized additive mixed model showed that sex, %CA, Ix/Iy, chronological period, and terrain significantly influenced variation in the robusticity indicator of H. sapiens femora. A linear mixed model revealed that none of the analyzed variables correlated with the femoral robusticity indicator of Neandertals. We did not confirm that the gradual decline in the femoral robusticity indicator of H. sapiens from the Middle Paleolithic to recent times is related to the type of lifestyle; however, it may be associated with lower levels of mechanical loading during adolescence. The lack of correlation between the analysed variables and the indicator of femoral robusticity in Neandertals may suggest that they needed a different level of mechanical stimulus to produce a morphological response in the long bone than H. sapiens.

Biomechanical properties of anuran long bones: correlations with locomotor modes and habitat use

Long bones are subjected to mechanical loads during locomotion that will influence their biomechanical properties through a feedback mechanism (the bone mechanostat). This mechanism adapts the spatial distribution of the mineralized tissue to resist compression, bending and torsion. Among vertebrates, anurans represent an excellent group to study long bone properties because they vary widely in locomotor modes and habitat use, which enforce different skeletal loadings. In this study, we hypothesized that (a) the cortical bone mass, density and design of anuran femur and tibiofibula would reflect the mechanical influences of the different locomotor modes and habitat use, and (b) the relationships between the architectural efficiency of cortical design (cross-sectional moments of inertia) and the intrinsic stiffness of cortical tissue [cortical mineral density; the 'distribution/quality' (d/q) relationship] would describe some inter-specific differences in the efficiency of the bone mechanostat to improve bone design under different mechanical loads. To test this hypothesis, we determined tomographic (peripheral quantitative computed tomography) indicators of bone mass, mineralization, and design along the femur and tibiofibula of four anuran species with different modes of locomotion and use of habitat. We found inter-specific differences in all measures between the distal and proximal ends and mid-diaphysis of the bones. In general, terrestrial-hopper species had the highest values. Arboreal-walker species had the lowest values for all variables except for cortical bone mineral density, which was lowest in aquatic-swimmer species. The d/q relationships showed similar responses of bone modeling as a function of cortical stiffness for aquatic and arboreal species, whereas terrestrial-hoppers had higher values for moments of inertia regardless of the tissue compliance to be deformed. These results provide new evidence regarding the significant role of movement and habitat use in addition to the biomechanical properties of long bones within a morpho-functional and comparative context in anuran species.

Study of surface wave vibration in rotating human long bones of cylindrical shape under the magnetic field influence

ABSTRACT Internal remodeling of Bone models describes the process by which bone adapts its histological structure to change in the long duration of mechanical load areas. In orthopedics, wave propagation over bone is used in monitoring the rate of fracture healing. The present problem studies the effect of initial stress, rotation and magnetic field on wave propagation in long dry bones. A dry long bone has been considered as an orthotropic hollow cylinder. The equation of motion is solved in terms of displacements. Bisection method has been used to calculate the phase velocity of harmonic wave and frequencies of vibration in anisotropic long bone. Peculiar effects of rotation, initial stress, surface span and magnetic field on vibrations in long bone medium have been investigated and presented through graphs. The present study finds its applications in wave propagation and vibration test to determine the vivo properties of long bones. As an outcome, there is a significant effect of initial stress on long bone structure as compared to rotation and magnetic parameter. Findings may also be useful for theoretical development of orthopedic studies related to cylindrical poroelastic long bones.

Effect of an iodophor-silicate disinfecting and cleaning agent on liver function tests, the structure of the small intestine, and bone parameters in a rat model study

The aim of the study was to assess the risk of using an iodophor disinfecting and cleaning agent based on clinoptilolite intended for dry disinfection in the presence of non-ruminants. In a rat model study, a suspension containing 103.3 mg/kg b. w. of the disinfectant (a dose of 0.1 of LD50) was administrated per os for a period of 21 days. Its toxicity was assessed on the basis of liver function tests. The effects of the disinfectant on the histological parameters of the duodenum and jejunum and on the properties of long bones were determined. Although the agent showed no toxicity, at the end of the experiment the experimental animals had lower body weights than the control group animals (P &lt; 0.01). The disinfectant exerted an adverse effect on the histological parameters of the jejunum, reducing the length of the intestinal villi (P &lt; 0.01) and the absorption area (P &lt; 0.05) and increasing the crypt depth (P &lt; 0.05). On the other hand, the presence of clinoptilolite positively influenced the parameters of long bones, increasing their mass (P &lt; 0.001), length (P &lt; 0.001), density (P &lt; 0.01), and ash content (P &lt; 0.01). In the bone metaphysis and epiphysis root, a significant increase was found in the trabecular bone volume (P &lt; 0.001) and the trabecular number (P &lt; 0.05). Bone fracture strength was also increased (P &lt; 0.05) in the experimental animals. The results obtained show that iodophores and clinoptilolite can be used in veterinary practice as components of low-toxic disinfecting and absorbing agents. However, the reduced body mass of the experimental animals suggests the need for further comprehensive tests aimed at determining the amount of the iodophor disinfecting and cleaning agent that does not impair performance parameters.

Metformin Alleviates the Bone Loss Induced by Ketogenic Diet: An In Vivo Study in Mice.

Metformin (Met), an anti-diabetes drug, has also shown therapeutic effects for ovariectomy-induced (OVX) osteoporosis. However, similar effects against bone loss induced by a ketogenic diet (KD) have not been tested. This study was aimed to evaluate the microarchitectures and biomechanics of KD-induced osteoporosis with and without administration of Met, and compare the effect of Met on bone loss induced by KD with OVX. Forty female C57BL/6J mice were randomly divided into Sham, OVX, OVX + Met (100mg/kg/day), KD (3:1 ratio of fat to carbohydrate and protein), and KD + Met (100mg/kg/day) groups. After 12 weeks, the bone mass and biomechanics were measured in distal cancellous bone and in mid-shaft cortical bone of the femur. The activities of serum alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP), together with immunohistochemistry staining of osteocalcin (OCN) and TRAP, were evaluated. Both OVX and KDinduced significant bone loss and compromised biomechanical properties in the cancellous bone, but no effect was found in cortical bone. The administration of Met increased the cancellous bone volume fraction (BV/TV) from 3.78 to 5.23% following the OVX and from 4.04 to 6.33% following the KD, it also enhanced the compressive stiffness from 47 to 160N/mm following the OVX and from 35 to 340N/mm with the KD. Met effectively increased serum ALP in the KD group while decreased serum TRAP in the OVX group, but up-regulated expression of OCN and down-regulated expression of TRAP in both OVX and KD groups. The present study demonstrated that Met effectively attenuated the cancellous bone loss induced by KD and maintained the biomechanical properties of long bones, providing evidence for Met as a treatment of by KD-induced osteoporosis in teenage skeleton.

Predicting the bending properties of long bones: Insights from an experimental mouse model.

Analyses of bone cross-sectional geometry are frequently used by anthropologists and paleontologists to infer the loading histories of past populations. To address some underlying assumptions, we investigated the relative roles of genetics and exercise on bone cross-sectional geometry and bending mechanics in three mouse strains: high bone density (C3H/He), low bone density (C57BL/6), and a high-runner strain homozygous for the Myh4Minimsc allele (MM). Weanlings of each strain were divided into exercise (wheel) or control (sedentary) treatment groups for a 7-week experimental period. Morphometrics of the femoral mid-diaphysis and mechanical testing were used to assess both theoretical and ex vivo bending mechanics. Across all measured morphological and bending traits, we found relatively small effects of exercise treatment compared to larger and more frequent interstrain differences. In the exercised group, total distance run over the experimental period was not a predictor of any morphological or bending traits. Cross-sectional geometry did not accurately predict bone response to loading. Results from this experimental model do not support hypothesized associations among extreme exercise, cross-sectional geometry, and bending mechanics. Our results suggest that analysis of cross-sectional geometry alone is insufficient to predict loading response, and questions the common assumption that cross-sectional geometry differences are indicative of differential loading history.

Marcadores de estrés ocupacional en poblaciones históricas del norte de Mendoza (S. XVI-XVII): primeros resultados exploratorios

Las modificaciones producidas en restos óseos y dentales humanos son capaces de informarnos acerca de algunas de las demandas mecánicas ejercidas sobre el individuo a lo largo de su vida. El objetivo de este trabajo es presentar los primeros resultados exploratorios de un proyecto más amplio que busca conocer la forma y el grado de participación que tuvieron los miembros de la sociedad estamental en el sistema productivo colonial de la ciudad de Mendoza (s. XVI-XIX). El mismo será abordado a partir del análisis de Marcadores de Estrés Ocupacional en muestras bioarqueológicas procedentes de templos católicos coloniales del Área Fundacional (Ciudad de Mendoza). Se analizan dos individuos adultos de ambos sexos recuperados durante un rescate arqueológico en el punto arqueológico Santo Domingo (Ciudad de Mendoza). La metodología consiste en el análisis de MEO a partir del relevamiento de un conjunto de líneas analíticas: cambios entésicos, enfermedad degenerativa articular, marcadores de estrés mecánico postural, fracturas, propiedades geométricas en sección externa de huesos largos y patrones de desgaste dental. Se discuten patrones generales en el uso del cuerpo, ampliando el conocimiento que disponemos sobre la salud y estilos de vida de estas poblaciones.

Long-bone properties and development are affected by caponisation and breed in Polish fowls

ABSTRACT1. The aim of the study was to investigate the effects of caponisation on bone development of males of two native breeds in Poland.2. The weight, length and cross-sectional area of tibiae and femora were measured, densitometric measurements and tests of strength were determined and dimensions were calculated.3. Breed and caponisation did not influence bone weight and length. Higher mechanical strength of the femur was found in entire males, mainly in the Polbar breed. Tibial strength was reduced in capons of the Green Partridge breed. Maximum elastic strength was greater in the Polbar, irrespective of caponisation. Bone cross-sectional area was influenced by breed, while caponisation reduced femoral bone mineral density in both breeds.4. Caponisation thus increased growth rate but had adverse effects on bone development.5. Caponisation had fewer negative effects in the Polbar than in the Greenleg Partridge.

Dose-dependent effects of probiotic supplementation on bone characteristics and mineralisation in meat-type female turkeys

To evaluate the influence of the probiotic on bone tissue in female turkeys, bone mineral density and geometrical and mechanical properties of the tibia and femur were determined in a dose-dependent manner (107 colony-forming units (cfu)/g, 108 cfu/g, 109 cfu/g). No effect of the treatments on bone mass and wall thickness of femur was observed, but the administration of the probiotic resulted in the elongation and the reduction of both strengths. The increase in the cross-sectional area of the femur was dose-dependent. Probiotic supplementation at a concentration of 108 cfu/g resulted in a reduction in ultimate strength, but at a concentration of 107 cfu/g, it resulted in the enhancement of the maximum elastic strength of the tibia compared with other groups. The influence of the probiotic administration on tibia geometry was dose-dependent. No effect of the treatments on the relative bone weight and the ratio of mass to length was observed. In general, the influence of the probiotic administration on bone mineral density, bone mineral concentration, bone tissue density, and bone ash, calcium and phosphorus concentrations was dose-dependent. The investigated properties of long bones in female turkeys are affected through probiotic-supplemented diets in a dose-dependent manner. However, on the basis of densitometry, it seems that the administration of the probiotic at a higher concentration of cells is more beneficial for bone development in turkeys.

Mechanical and material properties of cortical and trabecular bone from cannabinoid receptor-1-null (Cnr1−/−) mice

The endocannabinoid system is known for its regulatory effects on bone metabolism through the cannabinoid receptors, Cnr1 and Cnr2. In this study we analysed the mechanical and material properties of long bones from Cnr1−/− mice on a C57BL/6 background. Tibiae and femora from 5- and 12-week-old mice were subjected to three-point bending to measure bending stiffness and yield strength. Elastic modulus, density and mineral content were measured in the diaphysis. Second moment of area (MOA2), inner and outer perimeters of the cortical shaft and trabecular fractional bone volume (BV/TV) were measured using micro-CT. In Cnr1−/− males and females at both ages the bending stiffness was reduced due to a smaller MOA2. Bone from Cnr1−/− females had a greater modulus than wild-type controls, although no differences were observed in males. BV/TV of 12-week-old Cnr1−/− females was greater than controls, although no difference was seen at 5-weeks. On the contrary, Cnr1−/− males had the same BV/TV as controls at 12-weeks while they had significantly lower values at 5-weeks. This study shows that deleting Cnr1 decreases the amount of cortical bone in both males and females at 12-weeks, but increases the amount of trabecular bone only in females.

Scaling effect on the mid-diaphysis properties of long bones-the case of the Cervidae (deer).

How skeletal elements scale to size is a fundamental question in biology. While the external shape of long bones was intensively studied, an important component of their organization is also found in their less accessible inner structure. Here, we studied mid-diaphyseal properties of limb long bones, characterizing notably the thickness of their cortices (bone walls), in order to test whether body size directly influences bone inner organization. Previous examinations of scaling in long bones used broad samplings to encompass a wide range of body sizes. To account for the effect of confounding factors related to different lifestyles, we focused our comprehensive sampling on a mammalian clade that comprises various body sizes but a relatively uniform lifestyle, the Cervidae. Positive allometry was found in femoral cross-sectional shape, indicating greater directional bending rigidity in large-sized taxa. None of the compactness parameters scaled allometrically in any of their bones. The cortices of sampled zeugopodial bones (tibia and radius) were found as significantly thicker than those of stylopodial bones (femur and humerus). Furthermore, while the mean relative cortical thickness values for both stylopodial and zeugopodial bones are close to mass-saving optima, the variance for the stylopodial bones is significantly lower. This suggests that mass saving is less intensively selected in zeugopodial bones. Finally, the long-legged Elk (Alces) and the short-legged dwarf Cretan deer (Candiacervus) featured rather thin and thick cortices, respectively, suggesting that the acquisition of a different limb proportion is accompanied by a modification of the relative mid-diaphyseal cortical thickness.

Imaging Internal Structure of Long Bones Using Wave Scattering Theory.

An ultrasonic wavefield imaging method is developed to reconstruct the internal geometric properties of long bones using zero-offset data acquired axially on the bone surface. The imaging algorithm based on Born scattering theory is implemented with the conjugate gradient iterative method to reconstruct an optimal image. In the case of a multilayered velocity model, ray tracing through a smooth medium is used to calculate the traveled distance and traveling time. The method has been applied to simulated and real data. The results indicate that the interfaces of the top cortex are accurately imaged and correspond favorably to the original model. The reconstructed bottom cortex below the marrow is less accurate mainly because of the low signal-to-noise ratio. The current imaging method has successfully recovered the top cortical layer, providing a potential tool to investigate the internal structures of long bone cortex for osteoporosis assessment.

Cortical structure of hallucal metatarsals and locomotor adaptations in hominoids.

Diaphyseal morphology of long bones, in part, reflects in vivo loads experienced during the lifetime of an individual. The first metatarsal, as a cornerstone structure of the foot, presumably expresses diaphyseal morphology that reflects loading history of the foot during stance phase of gait. Human feet differ substantially from those of other apes in terms of loading histories when comparing the path of the center of pressure during stance phase, which reflects different weight transfer mechanisms. Here we use a novel approach for quantifying continuous thickness and cross-sectional geometric properties of long bones in order to test explicit hypotheses about loading histories and diaphyseal structure of adult chimpanzee, gorilla, and human first metatarsals. For each hallucal metatarsal, 17 cross sections were extracted at regularly-spaced intervals (2.5% length) between 25% and 65% length. Cortical thickness in cross sections was measured in one degree radially-arranged increments, while second moments of area were measured about neutral axes also in one degree radially-arranged increments. Standardized thicknesses and second moments of area were visualized using false color maps, while penalized discriminant analyses were used to evaluate quantitative species differences. Humans systematically exhibit the thinnest diaphyseal cortices, yet the greatest diaphyseal rigidities, particularly in dorsoplantar regions. Shifts in orientation of maximum second moments of area along the diaphysis also distinguish human hallucal metatarsals from those of chimpanzees and gorillas. Diaphyseal structure reflects different loading regimes, often in predictable ways, with human versus non-human differences probably resulting both from the use of arboreal substrates by non-human apes and by differing spatial relationships between hallux position and orientation of the substrate reaction resultant during stance. The novel morphological approach employed in this study offers the potential for transformative insights into form-function relationships in additional long bones, including those of extinct organisms (e.g., fossils).

The influence of electromagnetic radiation generated by a mobile phone on the skeletal system of rats.

The study was focused on the influence of electromagnetic field generated by mobile phone on the skeletal system of rats, assessed by measuring the macrometric parameters of bones, mechanical properties of long bones, calcium and phosphorus content in bones, and the concentration of osteogenesis (osteocalcin) and bone resorption (NTX, pyridinoline) markers in blood serum. The study was carried out on male rats divided into two groups: experimental group subjected to 28-day cycle of exposures in electromagnetic field of 900 MHz frequency generated by mobile phone and a control, sham-exposed one. The mobile phone-generated electromagnetic field did not influence the macrometric parameters of long bones and L4 vertebra, it altered mechanical properties of bones (stress and energy at maximum bending force, stress at fracture), it decreased the content of calcium in long bones and L4 vertebra, and it altered the concentration of osteogenesis and bone resorption markers in rats. On the basis of obtained results, it was concluded that electromagnetic field generated by 900 MHz mobile phone does not have a direct impact on macrometric parameters of bones; however, it alters the processes of bone mineralization and the intensity of bone turnover processes and thus influences the mechanical strength of bones.

Energy-restricted diet benefits body composition but degrades bone integrity in middle-aged obese female rats

This study investigates the effects of a restricted diet (RD) on body composition and musculoskeletal health along with endocrines and molecular mechanism in established mature obese rats. Twenty female rats were fed with a high-fat diet (HFD) ad libitum for 4 months and then assigned to either HFD or RD group for another 4 months. Another 10 rats were on a low-fat diet for 8 months. Outcome measures included body composition, bone mineral density, microarchitecrure, and strength; serum leptin, adiponectin, insulin-like growth factor I, and liver glutathione peroxidase activity; and protein expression and spleen tumor necrosis factor α messenger RNA expression. We hypothesized that mature obese rats on a 35% energy restriction diet for 4 months would improve body composition but degrade microstructural and mechanical properties of long bones, and such changes in musculoskeletal integrity are related to the modulation of obesity-related endocrines and proinflammation. Relative to HFD, RD benefited body composition (decreased body weight and %fat mass and increased %fat-free mass); decreased insulin-like growth factor I and leptin; elevated adiponectin, glutathione peroxidase activity and protein expression and tumor necrosis factor α messenger RNA expression; and suppressed bone formation and increased bone resorption, resulting in decreased trabecular and cortical bone volume, bone mineral density, and bone strength. Relative to low-fat diet, RD had a similar effect on body composition and serum markers but increased bone turnover rate and decreased bone mineral density and strength. Our data suggest that long-term RD has a negative impact on bone remodeling in obese female rats, probably through modification of endocrines and elevation of proinflammation.