Age-Dependent changes of mineral contents in men and women’s calcanei

To elucidate age-related change of mineral contents in human bones, the mineral content and density of human calcanei were determined by inductively coupled plasma atomic emission spectrometry and dual-energy X-ray absorptiometry. Calcanei were removed from 27 subjects (17 men and 10 women) who died in the age range from 40–98 yr old. Both the inductively coupled plasma emission spectrometry and dual-energy X-ray absorptiometry indicated that there were agedependent decreases of the mineral contents and density in the men’s calcaneus in the age range from 40–98 yr, but not in the women’s calcaneus in the age range from 42–87 yr. It was also found that the calcanean masses of the men and women remained constant within the same age range until 98 yr.     

High accumulations of calcium and phosphorus in women’s pubic symphysis

To elucidate compositional changes of the pubic symphysis (PS) by aging, elements of pubic symphyses (PSs) removed from 26 cadavers were determined by inductively coupled plasma atomic-emission spectrometry. It was found that the relative contents (RCs) of calcium and phosphorus in women’s PSs were about three-and five-fold amounts as compared with those in men’s PSs, respectively. In contrast, the RCs of sulfur, magnesium, sodium, and iron in women’s PSs were somewhat lower than those in men’s PSs. The accumulations of calcium (Ca) and phosphorus (P) in women’s PSs occurred mainly beyond the age of 70-yr-old, but did not occur in men’s PSs.     

Identification of sex from tarsal bones.

Bone weight as a discriminative factor for identification of sex was studied in tarsal bones (172 calcanei and 164 tali) from the Varanasi region. The DPs for the weight of these bones identified sex correctly in a good percentage of cases, especially from the male bones. The findings suggest weight of tarsal bones as a useful metrical feature for discriminating sexual dimorphism.     

Kinship,Family, and Gender Effects in the Ultimatum Game

Kinship and reciprocity are two main predictors of altruism. The ultimatum game has been used to study altruism in many small-scale societies. We used the ultimatum game to examine effects of individuals’ family and kin relations on altruistic behavior in a kin-based horticultural community in rural Dominica. Results show sex-specific effects of kin on ultimatum game play. Average coefficient of relatedness to the village was negatively associated with women’s ultimatum game proposals and had little effect on men’s proposals. Number of brothers in the village was positively associated with men’s ultimatum game proposals and negatively associated with women’s proposals. Similarly, presence of father in the village was associated with higher proposals by men and lower proposals by women. We interpret the effect of brothers on men’s proposals as a consequence of local competition among brothers. We speculate that daughter-biased parental care in this community creates a sense of entitlement among women with brothers, which may explain the inverse relation between number of brothers and women’s ultimatum game proposals. The pattern of results may be consistent with how matrifocality affects cultural models of fairness differently along gender and family lines.     

Willingness to engage in casual sex

Sexually dimorphic mate selection strategies were examined in 200 university students reporting their willingness to engage in casual sexual encounters with hypothetical individuals of the opposite sex. Using a questionnaire format, the possibility of forming a long-term relationship was manipulated, while risk of disease, pregnancy, and detection was eliminated across all conditions. In addition, potential partners varied in level of attractiveness, and in personality and behavioral characteristics. As expected, men reported a greater anticipated willingness to engage in sexual intercourse across all conditions compared with women. The possibility of forming a long-term relationship elevated women’s, but not men’s, willingness for sexual intercourse. While a potential partner’s attractiveness had a significant positive overall effect on responses, reducing their relative attractiveness had a greater negative impact on men’s responses. Reference to the parental qualities of a potential partner significantly increased women’s, but not men’s, anticipated willingness for sexual intercourse. Describing a hypothetical partner as non-aggressive (safe) marginally increased women’s willingness (p<.09) and did not affect men’s responses. The wording of items relevant to this condition may have resulted in the potential partner sounding "wimpy" rather than nonaggressive, and this may have reduced the expected effect of this manipulation. The possibility that women may trade off personality and behavioral characteristics with attractiveness to a greater degree than men when assessing potential mates is considered.     

Comparison of the hindfoot axes of a multi-segment foot model to the underlying bony anatomy

Musculoskeletal models used in gait analysis require coordinate systems to be identified for the body segments of interest. It is not obvious how hindfoot (or rearfoot) axes defined by skin-mounted markers relate to the anatomy of the underlying bones. The aim of this study was to compare the marker-based axes of the hindfoot in a multi-segment foot model to the orientations of the talus and calcaneus as characterized by their principal axes of inertia. Twenty adult females with no known foot deformities had radio-opaque markers placed on their feet and ankles at the foot model marker locations. CT images of the feet were acquired as the participants lay supine with their feet in a semi-weight bearing posture. The spatial coordinates of the markers were obtained from the images and used to define the foot model axes. Segmented masks of the tali and calcanei were used to create 3D bone models, from which the principal axes of the bones were obtained. The orientations of the principal axes were either within the range of typical values reported in the imaging literature or differed in ways that could be explained by variations in how the angles were defined. The model hindfoot axis orientations relative to the principal axes of the bones had little bias but were highly variable. Consideration of coronal plane hindfoot alignment as measured clinically and radiographically suggested that the model hindfoot coordinate system represents the posterior calcaneal tuberosity, rather than the calcaneus as a whole.     

Age-independent constancy of mineral contents in human vertebra and auditory ossicle

To elucidate age-related changes of mineral contents in human bones, element contents of human vertebrae and auditory ossicles were determined by inductively coupled plasma atomic-emission spectrometry. The cervical, thoracic, and lumbar vertebrae were removed from 12 vertebral columns. The mallei of auditory ossicle were removed from 27 cadavers. It was found that average relative contents (RCs) of calcium and phosphorus in cervical, thoracic, and lumbar vertebrae remained almost constant within ages ranging from 46 to 99 y. In addition, it was found that the RCs of calcium and phosphorus in men’s and women’s mallei remained constant within ages ranging from 40 to 98 yr. These results support the view that there is no significant agedependent change of mineral contents in human bones.     

Comparison of mandibular bone mineral density in osteoporotic, osteopenic and normal elderly edentulous subjects measured by the dual-energy X-ray absorptiometry technique

doi: 10.1111/j.1741‐2358.2012.00625.x Comparison of mandibular bone mineral density in osteoporotic, osteopenic and normal elderly edentulous subjects measured by the dual‐energy X‐ray absorptiometry technique Objective: The aim of this study was to compare the mandibular body bone mineral density according to bone mineral density status of spine and femur measured by dual‐energy X‐ray absorptiometry (DXA) technique in elderly edentulous individuals. Background: One of the factors that affect the survival rate of implants is bone mineral density (BMD) of the jaws. Materials and methods: Fifty edentulous elderly patients’ (27 women and 23 men) spine, femur and the mandibular body BMDs were measured using DXA technique. BMD scans of the AP lumbar spine (L2–L3) and femur were classified using World Health Organisation criteria for bone mass. Results: There was a statistically significant difference between the normal femur group’s–osteoporosis group’s mandibular body BMD (p = 0.001) and femoral osteopaenia group’s–osteoporosis group’s mandibular body BMD (p < 0.001). The femoral osteoporosis group’s mandibular body BMDs were lower than those of both the normal femoral and the femoral osteopaenia group subjects’. Conclusion: Classification of edentulous mandibles according to low and high bone mineral densities is a problem in implant dentistry. The results of this study demonstrated that femoral bone mineral density status may be used to provide preliminary information about the bone mineral density of the mandibular body region in elderly edentulous subjects.     

A possible balance of magnesium accumulations among bone, cartilage, artery, and vein in single human individuals

It is known that a large quantity of magnesium contains bones, and the magnesium contents in spongy bones decrease gradually with advancing age. To elucidate the relationships between a decrease of mineral contents in human bones and an accumulation of minerals in the other human tissues, the content of magnesium was analyzed by inductively coupled plasma-atomic emission spectrometry among human bones, arteries, veins, and cartilages in 27 subjects (17 men and 10 women). These were resected from the subjects who died in the age range 40–98 yr. Calcanei were chosen for analysis of magnesium contents in contrast with femoral, popliteal, and common carotid arteries, internal jugular and femoral veins, superior and inferior venae cavae, and pubic symphyses. The magnesium contents in the calcanei decreased gradually with aging, whereas they increased progressively in the arteries, veins, and pubic symphyses with aging. It was found that as the magnesium contents decreased in the calcanei, they increased in the arteries, such as the femoral, popliteal, and common carotid arteries, whereas they decreased inversely in the veins, such as the internal jugular and femoral veins and superior and inferior venae cavae. Furthermore, as the magnesium contents decreased in the calcanei, they hardly changed in the pubic symphyses. These suggest that magnesium released from bones is accompanied by accumulation of magnesium in the arteries.     

Accumulation of calcium and phosphorus in the mitral valve in comparison with the abdominal aorta and the scaphoid bone

To clarify why calcification of the mitral valve occurred, the authors chose the abdominal aorta and the scaphoid bone among many arteries and bones, and they studied both relationships in element contents between the mitral valve and the abdominal aorta and between the mitral valve and the scaphoid bone. The subjects consisted of 11 men and 8 women, ranging in age from 52 to 96 yr. The accumulation of calcium and phosphorus occurred progressively with aging in the mitral valve, whereas it became the highest in the sixties in the abdominal aorta and did not increase thereafter. The accumulation of calcium and phosphorus occurred in the abdominal aorta earlier than the thoracic aorta, in which it became remarkable in the seventies. It should be noted that in regard to the accumulation of calcium and phosphorus, no significant correlations were found between the mitral valve and the abdominal aorta. It is suggested that calcification of the abdominal aorta is not essentially accompanied by calcification of the mitral valve. The scaphoid bone was chosen among many bones consisting mainly of spongy bone and the relationship was examined between the calcium content in the mitral valve and the bone mineral density of the scaphoid bone. It was found that there was a low relationship between them. Therefore, it is suggested that a part of the surplus calcium released from bones is deposited in the mitral valve.     

A comparative study of the trabecular bony architecture of the talus in humans, non-human primates, and Australopithecus

This study tested the hypothesis that talar trabecular microarchitecture reflects the loading patterns in the primate ankle joint, to determine whether talar trabecular morphology might be useful for inferring locomotor behavior in fossil hominins. Trabecular microarchitecture was quantified in the anteromedial, anterolateral, posteromedial, and posterolateral quadrants of the talar body in humans and non-human primates using micro-computed tomography. Trabecular bone parameters, including bone volume fraction, trabecular number and thickness, and degree of anisotropy differed between primates, but not in a manner entirely consistent with hypotheses derived from locomotor kinematics. Humans have highly organized trabecular struts across the entirety of the talus, consistent with the compressive loads incurred during bipedal walking. Chimpanzees possess a high bone volume fraction, consisting of plate-like trabecular struts. Orangutan tali are filled with a high number of thin, connected trabeculae, particularly in the anterior portion of the talus. Gorillas and baboons have strikingly similar internal architecture of the talus. Intraspecific analyses revealed no regional differences in trabecular architecture unique to bipedal humans. Of the 22 statistically significant regional differences in the human talus, all can also be found in other primates. Trabecular thickness, number, spacing, and connectivity density had the same regional relationship in the talus of humans, chimpanzees, gorillas, and baboons, suggesting a deeply conserved architecture in the primate talus. Australopithecus tali are human-like in most respects, differing most notably in having more oriented struts in the posteromedial quadrant of the body compared with the posterolateral quadrant. Though this result could mean that australopiths loaded their ankles in a unique manner during bipedal gait, the regional variation in degree of anisotropy was similar in humans, chimpanzees, and gorillas. These results collectively suggest that the microarchitecture of the talus does not simply reflect the loading environment, limiting its utility in reconstructing locomotion in fossil primates.     

A MR imaging procedure to measure tarsal bone rotations

Magnetic resonance imaging offers unique insights into three-dimensional foot bone motion. Thereby, adequate devices enabling defined loading and positioning of the foot are needed to profit from this noninvasive procedure. Tarsal bone positions of three healthy subjects were repeatedly measured in a pronated and a supinated foot excursion under bodyweight with a newly developed MR imaging procedure. The quantification of the transferred motion from the loading and positioning device to the calcaneus and an estimation of the required degrees to distinguish between tarsal joint rotations were used to evaluate the applicability of the procedure to investigate tarsal joint motion. It was found that 45-70% (75-95%) of the externally applied 15 deg foot pronation (supination) were transferred to the calcaneus. Furthermore, the talonavicular joint showed the largest amount of rotation up to 20 deg eversion-inversion and abadduction, followed by the subtalar joint showing nearly half of that motion. Considerably less motion was found between the cuboid and calcaneus (about 2-6 deg) and the cuboid nearly did not rotate relative to the navicular (on average 1 deg). The estimated necessary differences between tarsal joint movements to identify individual kinematic behavior were in the order of 2 deg (4 deg related to the talonavicular joint). Since the results were in agreement with the literature, it is concluded that the applicability of the presented procedure to investigate tarsal bone mechanics is warranted. The possibility to evaluate 3D tarsal joint motion in combination with bone morphology (e.g., joint curvature) may provide new insights in the still uncertain relationship between foot function and foot morphology.     

Morphology of the facets of the proximal Tarsi bones from an ancient population

The analysis of morphological variation of tali and calcanei articular surfaces from “S'Illot des Porros” (Majorca, 2430±200 BP) has been made. It indicates the high frequency of extensions of the talocrural and subtalar surfaces, which are shown to be produced not only by a high level of stress on the bones. The presence of the sulcus tali facet in most cases could indicate, however, a greater degree of lateral movement of the foot.     

Foot bones from Omo: implications for hominid evolution

We reanalyze a hominid talus and calcaneus from Omo dating to 2.2 mya and 2.36 mya, respectively. Although both specimens occur at different localities and times, both tarsals articulate well together, suggesting a single taxon on the basis of size and function. We attribute these foot bones to early Homo on the basis of their morphology. The more modern-like tarsal morphology of these Omo foot bones makes them very similar to a talus from Koobi Fora (KNM-ER 813), a specimen attributed to Homo rudolfensis or Homo erectus. Although the Omo tarsals are a million years younger than the oldest known foot bones from Hadar, both localities demonstrate anatomical differences representing two distinct morphological patterns. Although all known hominid tarsals demonstrate clear bipedal features, the tarsal features noted below suggest that biomechanical changes did occur over time, and that certain features are associated with different hominid lineages (especially the robust australopithecines).     

Age-related changes of elements in human anterior cruciate ligaments and ligamenta capitum femorum

To elucidate compositional changes of human ligaments by aging, the content of elements in anterior cruciate ligaments (ACLs) and ligamenta capitum femorum (LCFs) was analyzed by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of 11 men and 7 women, ranging from 59 to 91 yr of age. With regard to the content of elements, the content of sulfur and iron was significantly higher in the LCFs than in the ACLs. It was found in the ACLs that the content of sulfur decreased gradually with aging, whereas the content of calcium, phosphorus, and magnesium increased progressively with aging. On the other hand, it was found in the LCFs that the content of magnesium decreased gradually with aging, whereas the content of phosphorus increased progressively with aging. The common finding that the content of phosphorus increased with aging, but the content of iron decreased, was obtained in the ACL and LCF. Regarding sexual difference, it was found in both the ACLs and LCFs that the content of phosphorus was higher in women’s ligaments than in men’s.     

How Willing Are You to Accept Sexual Requests from Slightly Unattractive to Exceptionally Attractive Imagined Requestors?

In their classic study of differences in mating strategies, Clark and Hatfield (1989, Journal of Psychology and Human Sexuality, 2, 39–54) found that men and women demonstrated a striking difference in interest in casual sex. The current study examined the role of an imagined requestor’s physical attractiveness (slightly unattractive, moderately attractive, and exceptionally attractive) on men’s and women’s willingness to accept three different requests (go out, come to apartment, go to bed) as reflected in answers to a questionnaire. We tested two hypotheses with a sample of 427 men and 443 women from three countries. Hypothesis 1 states that men, relative to women, will demonstrate a greater willingness to accept the “come to apartment” and “go to bed” requests but not the “go out” request for all three levels of requestor attractiveness. This hypothesis reflects Clark and Hatfield’s main findings. Hypothesis 2 states that the physical attractiveness of a potential partner will have a greater effect on women’s than on men’s willingness to accept all three requests, and particularly for the explicit request for casual sex. The results partially supported Hypothesis 1 and fully supported Hypothesis 2. The discussion highlights limitations of the current research and presents directions for future research.     

Talar articular facets (facies articulares talares) in human calcanei

The variations of the talar articular facets in 176 calcanei were studied and classified. Three types were considered: type A = calcanei with two articular facets for the talar head, with four subtypes; type B = calcanei with one articular facet for the talar head, and two subtypes, and type C = unique articular facies in the superior surface of the calcaneus for the talus. We found 53% (94 cases) type B calcanei and 46% (82 cases) type A calcanei. No calcanei of type C were seen.     

Relationships of loading history and structural and material characteristics of bone: development of the mule deer calcaneus

If a bone's morphologic organization exhibits the accumulated effects of its strain history, then the relative contributions of a given strain stimulus to a bone's development may be inferred from a bone's hierarchical organization. The artiodactyl calcaneus is a short cantilever, loaded habitually in bending, with prevalent compression in the cranial (Cr) cortex, tension in the caudal (Cd) cortex, and shear in the medial and lateral cortices (i.e., neutral axis). Artiodactyl calcanei demonstrate unusually heterogeneous structural and material organization between these cortices. This study examines potential relationships between developmental morphologic variations and the functional strain distribution of the deer calcaneus. One calcaneus was obtained from each of 36 (fetus to adult) wild deer. Predominant collagen fiber orientation (CFO), microstructural characteristics, mineral content (% ash), and geometric parameters were determined from transversely cut segments. Radiographs were examined for arched trabeculae, which may reflect tension/compression stress trajectories. Results showed that cross-sectional shape changes with age from quasi-circular to quasi-elliptical, with the long axis in the cranial-caudal direction of habitual bending. Cranial ("compression") cortical thickness increased at a greater rate than the Cd ("tension") cortex. Fetal bones exhibited arched trabeculae. Percent ash was not uniform (Cr > Cd), and this disparity increased with age (absolute differences: 2.5% fetuses, 4.3% adults). Subadult bones showed progressively more secondary osteons and osteocyte lacunae in the Cr cortex, but the Cd cortex tended to have more active remodeling in the subadult and adult bones. Nonuniform Cr:Cd CFO patterns first consistently appear in the subadults, and are correlated with secondary bone formation and habitual strain mode. Medial and lateral cortices in these groups exhibited elongated secondary osteons. These variations may represent "strain-mode-specific" (i.e., tension, compression, shear) adaptations. The heterogeneous organization may also be influenced by variations in longitudinal strain magnitude (highest in the Cr cortex) and principal strain direction-oblique in medial-lateral cortices (where shear strains also predominate). Other factors such as local reductions in longitudinal strain may influence the increased remodeling activity of the Cd cortex. Some structural variations, such as arched trabeculae, that are established early in ontogeny may be strongly influenced by genetic- or epigenetic-derived processes. Material variations, such as secondary osteon population densities and CFO, which appear later, may be products of extragenetic factors, including microdamage.     

Early Eocene lagomorph (Mammalia) from Western India and the early diversification of Lagomorpha

We report the oldest known record of Lagomorpha, based on distinctive, small ankle bones (calcaneus and talus) from Early Eocene deposits (Middle Ypresian equivalent, ca 53 Myr ago) of Gujarat, west-central India. The fossils predate the oldest previously known crown lagomorphs by several million years and extend the record of lagomorphs on the Indian subcontinent by 35 Myr. The bones show a mosaic of derived cursorial adaptations found in gracile Leporidae (rabbits and hares) and primitive traits characteristic of extant Ochotonidae (pikas) and more robust leporids. Together with gracile and robust calcanei from the Middle Eocene of Shanghuang, China, also reported here, the Indian fossils suggest that diversification within crown Lagomorpha and possibly divergence of the family Leporidae were already underway in the Early Eocene.     

Partner Status Influences Women’s Interest in the Opposite Sex

Previous research has demonstrated that hormones, relationship goals, and social context influence interest in the opposite sex. It has not been previously reported, however, whether having a current sexual partner also influences interest in members of the opposite sex. To test this, we obtained explicit and implicit measures of interest by measuring men’s and women’s subjective ratings and response times while they evaluated photos of opposite-sex faces. Fifty-nine men and 56 women rated 510 photos of opposite-sex faces for realism, masculinity, attractiveness, or affect. We found that these subjective ratings were not influenced by partner status in either men or women. However, women who did not report having a current sexual partner spent more time evaluating the photos than women who did have partners, demonstrating greater interest in the photos. Sexual partner status did not predict men’s response times. These findings may reveal that relationship commitment in women suppresses interest in alternative partners.