Age-related nitration/dysfunction of myogenic stem cell activator HGF.

Mechanical perturbation triggers activation of resident myogenic stem cells to enter the cell cycle through a cascade of events including hepatocyte growth factor (HGF) release from its extracellular tethering and the subsequent presentation to signaling-receptor c-met. Here, we show that with aging, extracellular HGF undergoes tyrosine-residue (Y) nitration and loses c-met binding, thereby disturbing muscle homeostasis. Biochemical studies demonstrated that nitration/dysfunction is specific to HGF among other major growth factors and is characterized by its locations at Y198 and Y250 in c-met-binding domains. Direct-immunofluorescence microscopy of lower hind limb muscles from three age groups of rat, provided direct in vivo evidence for age-related increases in nitration of ECM-bound HGF, preferentially stained for anti-nitrated Y198 and Y250-HGF mAbs (raised in-house) in fast IIa and IIx myofibers. Overall, findings highlight inhibitory impacts of HGF nitration on myogenic stem cell dynamics, pioneering a cogent discussion for better understanding age-related muscle atrophy and impaired regeneration with fibrosis (including sarcopenia and frailty).

Cross-sectional geometry of the femoral diaphyseal cortical bones: analysis of central mass distribution.

A detailed analysis of differences in skeletal shape among many individuals is expected to reveal the mechanical significance behind various morphological features. To confirm the distribution of the cortical bone region in cross sections, the relative position of the central mass distribution (CMD) of the cortical bone region to the CMD of the entire cross section was examined. A total of 90 right human femoral skeletons were examined using clinical multi-slice computed tomography. For nine cross sections of each femur, we determined the CMD of the whole area, including both cortical bone and medullary areas, as CMD-W, and that of the cortical bone region in the same cross section as CMD-C, and they were compared. The medial and anterior portion of the cortex was relatively thick just below the lesser trochanter. The posterior cortical bone tended to be relatively thick in the region from the center to the distal part of the diaphysis. Females had a significantly more medially deviated CMD than males throughout the entire diaphysis. These results suggest that femurs with advanced cortical bone thinning tend to have a concentration of cortical bone in their medial portion. CMD-C was located farther from the diaphysis axis as the degree of medial bending increased. Conversely, the greater the lateral bending of the diaphysis, the closer CMD-C was to the diaphysis axis. As the amount of bone decreases with age, self-adjustment could occur so that the cortical bone's critical area remains to prevent a decrease in mechanical strength.

Similarities and Differences in Bone Mineral Density between Multiple Sites in the Same Individual: An Elderly Cadaveric Study.

Bone mineral density (BMD) is known to vary based on various factors, and the degree of variation is site-specific. However, few studies have investigated the relationship between bone density at trabecular bone-rich and cortical bone-rich sites in the same individual. In this study, we attempted to measure BMD at multiple sites using whole-body computed tomography images taken immediately after death and to clarify the similarities and differences between skeletal sites. Additionally, we aimed to examine the factors that influence changes in BMD, such as the loading environment, bone microstructure, and the ossification process of each skeletal region. A 3D model containing BMD data of the skull, clavicle, lumbar vertebrae, and femur (neck and diaphysis) was created using computed tomography images taken immediately after the death of 60 individuals (28 men and 32 women, average age: 84.0 years) who consented to participate in the study before death. Arbitrary measurement sites were defined, and bone density was measured at each site. We found that the BMDs of all regions were negatively correlated with age, but this correlation was weaker in the skull than in other regions. The negative correlation was especially pronounced in areas with more trabecular bones in men and in areas with more cortical bones in women. Furthermore, these findings suggest that factors, such as the loading environment, bone microstructure, and the ossification process of the skeletal sites, affect the BMD. Furthermore, our results suggest that it is important to assess the BMD of cortical bone in older women.

Morphological divergence in the curvature of human femoral diaphyses: Tracing the central mass distributions of cross-sections.

The diaphysis of the human femoral bone has a physiological anterior curvature; additionally, there is a curvature to the medial side or lateral side. In addition to compression stress from gravity during standing, walking, and running, these bones are continuously exposed to complex stresses from the traction forces of the various strong muscles attached to them. The femoral diaphysis is subjected to these mechanical stresses, and the direction and size of its curvature are defined according to Wolff's law and the mechanostat theory of Frost. The purpose of this study was to quantitatively evaluate the curvature of the femoral diaphysis in Japanese skeletons by determining the curve connecting the central mass distributions (CMD) of cross-sectional images. A total of 90 right femora (46 males and 44 females) were randomly selected from modern Japanese skeletal specimens. Full-length images of these bones were acquired using a clinical computed tomography scanner. The range between the lower end of the lesser trochanter and the adductor tubercle of each femur was divided at regular intervals to obtain ten planes, and nine levels were analyzed. The CMD curve was determined by connecting the CMDs of each of the nine cross-sections. First, the CMD of a cross-section in each of the nine slices was calculated, and the nine trajectories were superimposed from above. Then, by converting the shape of the entire CMD curve to superimpose the coordinates of the endpoint on the starting point, a closed arc representing the curvature of the femur was determined. For both males and females, the patterns varied from mostly medial to largely lateral curvature. The size of the curvature also varied for individuals. By analyzing only the coordinates of the vertex of the CMD curve of each femoral bone, the outlines of the diaphyseal curvatures could be recognized. The femora were thereby divided into two groups: medial bending and lateral bending. Considering males and females together, the number in the lateral-curvature group (n = 51) was larger than that in the medial-curvature group (n = 39). Moreover, the average age of the lateral-curvature group was significantly higher than that of the medial-curvature group (p < 0.05). In males, with an increase in the cortical bone proportion of the cross-sectional area, the anterior vertex of diaphyseal bending tended to be more prominent. This cortical proportion was significantly higher in the medial-curvature groups than in the lateral-curvature group (p < 0.01). The phenomena observed in this study may be related to pathophysiologies such as atypical fractures of the femur and osteoarthritis of the knee joints.

Course of the thoracic nerves around the umbilicus within the posterior layer of the rectus sheath: a cadaver study.

Rectus sheath block is used to anesthetize thoracic nerves around the umbilicus. However, the appropriate point for anesthetic injection during rectus sheath block has not been determined anatomically. Here, we examined the course of thoracic nerve T10 at the posterior layer of the rectus sheath and the anatomical relationship between the nerve and the rectus abdominis and transversus abdominis muscles in formalin-fixed adult cadavers. The cranio-caudal distance from a horizontal line running through the umbilicus to where the thoracic nerve T10 passes through the posterior layer of the rectus sheath was 33.8 ± 14.4 (mean ± standard deviation) mm, while that from the horizontal line running through the umbilicus to the position where the lateral edge of the rectus abdominis muscle and the medial border of the transversus abdominis muscle cross was 33.1 ± 17.1 mm. The position where the lateral edge of the rectus abdominis muscle and the medial border of the transversus abdominis muscle cross approximates the position where thoracic nerves T10 passes through the posterior layer of the rectus sheath. Our results identify effective landmarks to guide the performance of rectus sheath block.

Sex-based differences in human sacroiliac joint shape: a three-dimensional morphological analysis of the iliac auricular surface of modern Japanese macerated bones.

The human pelvis is one of the skeletons where sex differences are expressed, but few detailed studies have been conducted on sex-related differences in the sacroiliac joint morphology. Therefore, we conducted a three-dimensional morphological analysis evaluation of the sacroiliac joints to clarify the sex-related difference of the joint's morphology. Right-side macerated innominate bones of Japanese males (n = 100) and females (n = 70) whose ages at death were recorded were included in the study. Three-dimensional images were created from the subjects' iliac auricular surface images, and 16 measurement parameters were acquired on the basis of 11 defined measurement points. All measurement parameters were compared between the male and female groups. The values of the measurement parameters indicating the size of the iliac auricular surface were significantly larger in the male group than in the female group. In addition, the angle between the short and long arms of the auricular surface was larger in the male group. Furthermore, on the basis of the corrected values of the physical disparity, the long arm dimension of the iliac auricular surface was larger in the male group, while the short arm dimension was larger in the female group. The sex-based differences in the iliac auricular surface morphology that were confirmed in this study may reflect the sex-based differences in the sacroiliac joint function. The findings of this study may contribute to the elucidation of the pathophysiology of the sacroiliac joint dysfunction that frequently occurs in women.

Morphological profile of atypical femoral fractures: age-related changes to the cross-sectional geometry of the diaphysis.

The use of bisphosphonates for osteoporosis patients has markedly decreased the incidence of femoral neck or trochanteric fractures. However, anti-osteoporosis drugs have been reported to increase the incidence of atypical femoral fractures, which involve stress fractures in the subtrochanteric region or the proximal diaphysis. In this study, the morphological characteristics of the cortical bone in human femoral diaphysis samples were analyzed from individuals who lived before bisphosphonate drugs were available in Japan. A total of 90 right femoral bones were arbitrarily selected (46 males and 44 females) from modern Japanese skeletal specimens. Full-length images of these femurs were acquired using a computed tomography scanner. An image processing method for binarization was used to calculate the threshold values of individual bones for determining their contours. The range between the lower end of the lesser trochanter and the adductor tubercle of each femur was divided at regular intervals to obtain 10 planes. The mean value of cortical bone thickness, periosteal border length, and the cortical cross-sectional area was evaluated for all planes. Moreover, the ratio of the area of the cortical bone to the total area of cross-section at the mid-diaphysis was calculated. A comparison between males and females demonstrated that most females had lower cortical bone area ratios at the mid-diaphysis. The femoral outer shape did not differ markedly according to age or sex; however, substantial individual differences were observed in the shape of the inner surface of the cortical bone. The cortical bone thickness and the cross-sectional area decreased with age in the femoral diaphysis; furthermore, in females, the decrease was higher for the former than for the latter. This may be due to a compensatory increase in the circumference of the femoral diaphysis. In addition, in about half of the subjects there was a discrepancy between the region with maximal value of the cortical bone thickness and that of the total cross-sectional area. Biological responses to mechanical stresses to the femoral diaphysis are thought not to be uniform. Bisphosphonates inhibit bone resorption and may promote non-physiological bone remodeling. Thus, a nonhomogeneous decrease in cortical thickness may be related to the fracture occurrence in the femoral diaphysis in some cases. Thus, long-term administration of bisphosphonates in patients with morphological vulnerability in the femoral cortical bones may increase the occurrence of atypical femoral fractures.

Anatomical study of the articular branches innervated the hip and knee joint with reference to mechanism of referral pain in hip joint disease patients.

INTRODUCTION: Referred pain in the anterior knee joint is the most common symptom in hip disease patients. The development of referred pain is considered to be related to dichotomizing peripheral sensory fibers. However, no gross anatomical findings identify any dichotomizing fibers innervating both the hip and knee joints. We dissected the femoral and obturator nerves in human cadavers to investigate the distribution of the articular branches in the hip and knee joints. Fourteen embalmed left lower limbs from 14 Japanese adult cadavers (five from females, nine from males, average age 73.8 ± 14.1 years) were observed macroscopically. The articular branches of the femoral and obturator nerves were dissected at the anterior margin of the groin toward the thigh region. After dissections of the articular nerves of the hip joints, the femoral and obturator nerves were exposed from proximally to distally to identify the articular nerves of the knee joints. The branching pattern of the articular branches in the hip and knee joints was recorded. In six of 14 limbs (42.9%), the femoral nerve supplied articular branches to the anteromedial aspect of both the hip and knee joints. These articular branches were derived from the same bundle of femoral nerve. These gross anatomical findings suggested that dichotomizing peripheral sensory fibers innervate the hip and knee joints and these could relate to the referred pain confirmed in the anterior knee joints of patients with hip disease. Clin. Anat. 31:705-709, 2018. © 2018 Wiley Periodicals, Inc.

Three-dimensional morphological analysis of the human sacroiliac joint: influences on the degenerative changes of the auricular surfaces.

The sacroiliac joint (SIJ) is responsible for weight transmission between the spine and lower extremity. However, details of the structure and function of the SIJ remain unclear. In a previous study, we devised a method of quantitatively evaluating the level of degeneration of the SIJ using an age estimation procedure for the auricular surface of the ilium. Our results in that study suggested that the degree of degeneration of the joint surface may be associated with the morphology of the auricular surface of the ilium. In that study, however, the morphology of the auricular surface of the ilium was simplified for analysis, meaning that more detailed investigations were required in future. In the present study, we focused on individual differences in the shape of SIJ and carried out three-dimensional quantitative evaluation of the morphology of the auricular surface of the ilium to ascertain its association with joint degeneration. We produced three-dimensional images of the right auricular surfaces of the ilium of 100 modern Japanese men (age 19-83), and obtained the three-dimensional rectangular coordinates of 11 defined measurement points. We then calculated 16 parameters indicating the morphological characteristics of the auricular surfaces of the ilium from the three-dimensional rectangular coordinates of these measurement points, and used these to perform principal component analysis to investigate trends in the morphology of the auricular surface of the ilium. We found that the morphology of the auricular surface of the ilium could be characterized in terms of (i) size, (ii) concavity of the posterior border and (iii) amount of undulation. An investigation of the correlation between these parameters and age suggested that the amount of undulation of the auricular surface of the ilium tends to diminish with advancing age. In an investigation of the association between morphology of the auricular surface of the ilium and degeneration of the articular surface when the subjects were divided into a high-degeneration group (n = 55) and a low-degeneration group (n = 45) and the 16 parameters were compared, there was a significant difference in the amount of undulation of the auricular surface of the ilium. In an investigation limited to older subjects aged ≥ 60 (n = 47) at the time of death, there were significant differences between the high-degeneration group (n = 27) and low-degeneration group (n = 20) in terms not only of the parameters indicating the amount of undulation of the auricular surface of the ilium but also of those indicating the amount of the concavity of the posterior border. These results suggested that the amount of undulation of the auricular surface of the ilium may affect the degree of degeneration of the articular surface. In addition, in older subjects, the degree of concavity of the posterior border of the SIJ may also affect the degree of degeneration of the articular surface. It is thus likely that differences in the morphology of the auricular surface of the ilium may affect degenerative changes in the SIJ.

A case of anomalous horizontal fissure and hypoplastic middle lobe of the right lung / Un caso de fisura horizontal anómala y lóbulo medio hipoplásico del pulmón derecho

During dissection practice for medical students at Nagasaki University, a horizontal fissure and hypoplastic middle lobe were encountered in the right lung of an 81-year-old Japanese female. In a normal right lung, the horizontal fissure is situated anterior to the oblique fissure. On the contrary, in the present case, the horizontal fissure was situated posterior to the oblique fissure. We identified a small, additional lobe on the medial surface of this lung. It was situated in the medial part of the oblique fissure, and was determined to be a small hypoplastic middle lobe. As a result of the hypoplasia of the middle lobe, the original horizontal fissure may have disappeared from the anterior surface. The horizontal fissure, in this case, may be a compensatory additional fissure that developed within the inferior lobe. This horizontal fissure was incomplete, both in length and depth. The left lung was normal. This case might be very rare; however, it may aid in the understanding of normal lung development. Therefore, we report this case, including its bronchial branching and vascular distribution.

Durante la práctica de disección para estudiantes de medicina en la Universidad de Nagasaki, se encontró una fisura horizontal y un lóbulo medio hipoplásico en el pulmón derecho de una mujer japonesa de 81 años de edad. En un pulmón derecho normal, la fisura horizontal está situada anterior a la fisura oblicua. Por el contrario, en el presente caso, la fisura horizontal estaba situada posterior a la fisura oblicua. Se identificó un pequeño lóbulo adicional en la superficie medial de este pulmón. Estaba situado en la parte medial de la fisura oblicua, y se determinó que era un pequeño lóbulo medio hipoplásico. Como resultado de la hipoplasia del lóbulo medio, la fisura horizontal original puede haber desaparecido de la superficie anterior. La fisura horizontal, en este caso, puede ser una fisura adicional compensatoria que se desarrolla dentro del lóbulo inferior. Esta fisura horizontal era incompleta, tanto en longitud como en profundidad. El pulmón izquierdo era normal. Este caso podría ser muy raro; Sin embargo, puede ayudar en la comprensión del desarrollo pulmonar normal. Por lo tanto, informamos este variación, incluyendo su ramificación bronquial y la distribución vascular.

Deep and superficial circumflex iliac arteries and their relationship to the ultrasound-guided femoral nerve block procedure: A cadaver study.

The in-plane lateral to medial approach is a standard technique for ultrasound-guided femoral nerve block (USG-FNB). The first bifurcation of the femoral artery, which consists of the deep artery of the thigh (DAT) or occasionally the lateral circumflex femoral artery (LCFA), is regarded as the distal border for this procedure. We sometimes detect arteries along the estimated needle trajectory for USG-FNB. The superficial (SCIA) and deep (DCIA) circumflex iliac arteries run laterally parallel to the inguinal ligament from the femoral or external iliac artery. The relationship between the SCIA and DCIA and other anatomical structures related to USG-FNB around the femoral triangle region was studied by gross anatomical examination of 100 formalin-fixed adult cadavers. At least one SCIA and one DCIA were identified around each femoral triangle; 81.8% of SCIA and 58% of DCIA originated from the femoral artery. All DCIA coursed between the fascia lata and fascia iliaca and 80% of SCIA penetrated the fascia lata. In 94% of femoral triangles, at least one arterial branch heading towards the lateral part of the thigh originated from the femoral artery from the level of the inguinal ligament to the first bifurcation of the femoral artery. The presence of SCIA and DCIA should be considered during USG-FNB using the in-plane lateral to medial approach to avoid inadvertently injuring them, as they are occasionally located along the presumed needle trajectory superficial to the fascia iliaca. Clin. Anat. 30:413-420, 2017. © 2017 Wiley Periodicals, Inc.

Degenerative changes of the sacroiliac auricular joint surface-validation of influential factors.

The purpose of this study was to clarify the relevance of degenerative changes in the sacroiliac joint (SIJ) and the joints in the lower limb and lumbar spine using age estimation methods. We also examined the shape of the auricular surface to determine the effect of degenerative changes on each joint. A total of 200 iliac auricular surfaces from 100 Japanese male skeletons were examined macroscopically in accordance with conventional methods of age estimation. From the obtained estimated age, we calculated the deflection values, which represented the degree of degenerative changes of the joints. For comparison, we used osteophyte score data of the hip, knee, and zygapophyseal joints in lumbar spines from previous studies which had used the same bone specimens. As a quantitative indicator of auricular surface morphology, we defined the constriction ratio (CR) of the auricular surface and compared the CR values obtained with various measured values. Degenerative changes in the SIJ were positively correlated with those in both the hip joint and zygapophyseal joint, but a correlation with knee joints was found only on the left side. In skeletons from individuals aged ≥60 years as time of death, the CR was significantly different between the group with high scores and those with low scores in both the hip and sacroiliac joints. It has been suggested that degenerative changes in SIJs interact with those in the hip joint and zygapophyseal joint. In addition, the shape of the auricular surface may also be a relevant factor for degenerative changes in these joints.

Sex differences of dental pathology in early modern samurai and commoners at Kokura in Japan.

So-called "Ohaguro", teeth blackening, in the married females was a general custom regardless of class in the early modern period. As a result, Ohaguro was thought to have enhanced the acid resistance of tooth substance and tightened gingiva and prevented tooth morbidity due to periodontal disease. For investigation into the influence of Ohaguro, the skeletal remains of early modern samurai and commoners at Kokura were examined for differences in the dental pathology based on sex. Though females from archeological sites have significantly more carious teeth and antemortem tooth loss (AMTL) than males in the previous studies, the prevalence of caries and AMTL in males was higher than in females among the early modern samurai and commoners in Kokura. The efficacies of Ohaguro may influence the good dental health of females. On the other hand, as females were considered inferior to males under the feudal system in Japan, males, including children, might tend to consume more nutritious foods compared to females. However, those foods are certainly not better with regard to dental health, since those foods are more highly cariogenic. These factors may have caused higher caries and AMTL prevalence among males compared to females in early modern Kokura.

Tooth size in Chinese Oroqen ethnic minority of Inner Mongolia Autonomous Region.

The Oroqen are Tungusic hunters of the Amur River basin. We analyzed dental crown measurements from their dental impression models for anthropological characteristics. Sex difference was comparatively larger in the mesiodistal diameters. To examine the Mongoloids' distribution in the Northeast Asia, the data were compared with the results from the previous studies on other Northeast Asian races, using deviation diagrams, cluster analysis, and Multidimensional Scaling from Q-mode correlation coefficients. The Oroqen dentition is classified as Sinodont by the large surface area of their crowns. In the deviation diagram, the Oroqen beared an inverse proportion to the Aleutian Islanders, while showing little difference from the Okhotsk culture people, which suggested a close relation between the two races. The Q-mode correlation coefficients clustered the Oroqen into the Central Asian group with the Buriats and Mongolians. In the analysis of the distances transformed from Q-mode correlation coefficients, the Oroqen was delineated in the neighboring cluster to the Epi-Jomon/Satsumon and the Okhotsk people. It is inferred that the Central Asian group, spreading from Lake Baikal to the Amur basin have gradually mixed with the Baikal group, which later moved into the Amur region from the south. The mixing of the two groups could have been influenced by the geographical features of this area. It would be valuable to gather more data on the groups around the lower Amur region and to evaluate the distribution of the Mongoloids in Eastern Asia.

Characterization of individuals with sacroiliac joint bridging in a skeletal population: analysis of degenerative changes in spinal vertebrae.

The aim of this study was to characterize the individuals with sacroiliac joint bridging (SIB) by analyzing the degenerative changes in their whole vertebral column and comparing them with the controls. A total of 291 modern Japanese male skeletons, with an average age at death of 60.8 years, were examined macroscopically. They were divided into two groups: individuals with SIB and those without bridging (Non-SIB). The degenerative changes in their whole vertebral column were evaluated, and marginal osteophyte scores (MOS) of the vertebral bodies and degenerative joint scores in zygapophyseal joints were calculated. SIB was recognized in 30 individuals from a total of 291 males (10.3%). The average of age at death in SIB group was significantly higher than that in Non-SIB group. The values of MOS in the thoracic spines, particularly in the anterior part of the vertebral bodies, were consecutively higher in SIB group than in Non-SIB group. Incidence of fused vertebral bodies intervertebral levels was obviously higher in SIB group than in Non-SIB group. SIB and marginal osteophyte formation in vertebral bodies could coexist in a skeletal population of men. Some systemic factors might act on these degenerative changes simultaneously both in sacroiliac joint and in vertebral column.

Investigation and macroscopic anatomical study of referred pain in patients with hip disease.

[Purpose] The aim of this study was to examine the incidence and patterns of referred pain in patients with hip disease, as well as the nerve distribution in the hip and knee joints of 2 cadavers. [Subjects and Methods] A total of 113 patients with hip joint disease were included in the investigation. The incidence of regional pain and referred pain patterns were evaluated before and after arthroplasty. Two cadavers were macroscopically observed to verify the nerve innervation of the hip and knee joints. [Results] Anterior knee pain was observed preoperatively in 13.3% (in resting) and 33.6% (in motion) of the patients, which was comparable with the incidence of greater trochanter pain. In addition, the preoperative incidence rates of knee pain in resting and motion markedly decreased postoperatively. Of note is the remarkable incidence of pain radiating to the ventral lower limb. An anteromedial innervation was determined in the cadavers by the articular branches of the obturator and femoral nerve, which supply small branches to the knee joints. [Conclusion] Our results suggest that the distribution of the incidence of pain among the patients with hip disease is diverse owing to the sensory distribution of the femoral and obturator nerves.

Periarticular osteophytes as an appendicular joint stress marker (JSM): analysis in a contemporary Japanese skeletal collection.

OBJECTIVE: The aim of this study was to investigate the possibility that periarticular osteophytes plays a role as a appendicular joint stress marker (JSM) which reflects the biomechanical stresses on individuals and populations. METHODS: A total of 366 contemporary Japanese skeletons (231 males, 135 females) were examined closely to evaluate the periarticular osteophytes of six major joints, the shoulder, elbow, wrist, hip, knee, and ankle and osteophyte scores (OS) were determined using an original grading system. These scores were aggregated and analyzed statistically from some viewpoints. RESULTS: All of the OS for the respective joints were correlated logarithmically with the age-at-death of the individuals. For 70 individuals, in whom both sides of all six joints were evaluated without missing values, the age-standardized OS were calculated. A right side dominancy was recognized in the joints of the upper extremities, shoulder and wrist joints, and the bilateral correlations were large in the three joints on the lower extremity. For the shoulder joint and the hip joint, it was inferred by some distinctions that systemic factors were relatively large. All of these six joints could be assorted by the extent of systemic and local factors on osteophytes formation. Moreover, when the age-standardized OS of all the joints was summed up, some individuals had significantly high total scores, and others had significantly low total scores; namely, all of the individuals varied greatly in their systemic predisposition for osteophytes formation. CONCLUSIONS: This study demonstrated the significance of periarticular osteophytes; the evaluating system for OS could be used to detect differences among joints and individuals. Periarticular osteophytes could be applied as an appendicular joint stress marker (JSM); by applying OS evaluating system for skeletal populations, intra-skeletal and inter-skeletal variations in biomechanical stresses throughout the lives could be clarified.

Mitochondrial DNA analysis of Yayoi period human skeletal remains from the Doigahama site.

We analyzed the mitochondrial DNA extracted from 14 human skeletal remains from the Doigahama site in Japan to clarify the genetic structure of the Doigahama Yayoi population and the relationship between burial style and kinship among individuals. The sequence types obtained in this study were compared with those of the modern Japanese, northern Kyushu Yayoi and ancient Chinese populations. We found that the northern Kyushu Yayoi populations belonged to the groups that include most of the modern Japanese population. In contrast, most of the Doigahama Yayoi population belonged to the group that includes a small number of the modern Japanese population. These results suggest that the Doigahama Yayoi population might have contributed less to the formation of the modern Japanese population than the northern Kyushu Yayoi populations. Moreover, when we examined the kinship between individuals in the Doigahama site, we found that the vicinal burial of adult skeletons indicated a maternal kinship, although that of juvenile skeletons did not. The vicinal burial style might have been influenced by many factors, such as paternal lineages, periods and geographical regions, as well as maternal lineages. In addition, skeletons considered to be those of shamans or leaders had the same sequence types. Their crucial social roles may have been inherited through maternal lineage.

Dental morphology of the Dawenkou Neolithic population in North China: implications for the origin and distribution of Sinodonty.

We compare the incidence of 25 nonmetric dental traits of the people of the Neolithic Dawenkou culture (6300-4500 BP) sites in Shandong Province, North China with those of other East Asian populations. The Dawenkou teeth had an overwhelmingly greater resemblance to the Sinodont pattern typical of Northeast Asia than to the Sundadont pattern typical of Southeast Asia. Multidimensional scaling using Smith's mean measure of divergence (MMD) statistic place the Dawenkou sample near the Amur and the North China-Mongolia populations in the area of the plot indicating typical Sinodonty. The existence of the Sinodont population in Neolithic North China suggests a possible continuity of Sinodonty from the Upper Cave population at Zhoukoudian (about 34000-10000 BP) to the modern North Chinese. The presence of Sinodonty in Shandong Province shows that the Japan Sea and East China Sea were strong barriers to gene flow for at least 3000 years, because at this time the Jomonese of Japan were fully Sundadont. In addition, we suggest that the descendants of the Dawenkou population cannot be excluded as one of the source populations that contributed to sinodontification in Japan.