Anatomical Science International最新文献

Morphological analysis of organelles is one of the important clues for understanding the cellular conditions and mechanisms occurring in cells. In particular, nanoscale information within crowded intracellular organelles of tissues provide more direct implications when compared to analyses of cells in culture or isolation. However, there are some difficulties in detecting individual shape using light microscopy, including super-resolution microscopy. Transmission electron microscopy (TEM), wherein the ultrastructure can be imaged at the membrane level, cannot determine the whole structure, and analyze it quantitatively. Volume EM, such as focused ion beam/scanning electron microscopy (FIB/SEM), can be a powerful tool to explore the details of three-dimensional ultrastructures even within a certain volume, and to measure several parameters from them. In this review, the advantages of FIB/SEM analysis in organelle studies are highlighted along with the introduction of mitochondrial analysis in injured motor neurons. This would aid in understanding the morphological details of mitochondria, especially those distributed in the cell bodies as well as in the axon initial segment (AIS) in mouse tissues. These regions have not been explored thus far due to the difficulties encountered in accessing their images by conditional microscopies. Some mechanisms of nerve regeneration have also been discussed with reference to the obtained findings. Finally, future perspectives on FIB/SEM are introduced. The combination of biochemical and genetic understanding of organelle structures and a nanoscale understanding of their three-dimensional distribution and morphology will help to match achievements in genomics and structural biology.

Variations appearing in biceps brachii muscle are common with accessory head, different origins, variant insertion, and different pattern of nerve innervation. However, variations appearing in both origin and insertion, and with other anomalous morphology at the same time are seldom. Here we report a complex variational case on the right arm of a 91-year-old Japanese female cadaver. The complex variations included (1) the biceps brachii muscle bifurcated at its distal ending; (2) the long head had its own tendon, which divided into two parts, i.e., a lateral part fused into the fascia between the brachioradialis and extensor carpi brevis, and a medial part attached to the radius about one centimeter ahead of the radial tuberosity; (3) the short head had an accessory origin from the shoulder capsule; (4) the bicipital aponeurosis was of two parts with an anterior superior layer formed by the long head and a posterior deep one formed by the short head; (5) the musculocutaneous nerve was especially underdeveloped that only innervated the coracobrachialis; (6) the existence of communicating branch between the musculocutaneous and median nerves, and the median nerve issued muscular branches to the biceps brachii and brachialis muscles, and (7) the brachioradial muscle had two accessory muscular bundles that originated from the fascia of the brachial muscle (proximal one) and from the bicipital aponeurosis (distal one).

This study investigated differences in the fibular diaphyseal curvature between prehistoric Jomon hunter–gatherers and modern Japanese people. A total of 115 skeletal remains of 40 individuals from the Late/Final Jomon period (approximately 4300–2500 years BP) and 75 modern Japanese individuals were included in the analysis. The degree of anteroposterior and mediolateral diaphyseal curvature was measured based on digital photographs taken from the frontal and sagittal planes at every 5% diaphyseal region between the range of 20–80% of the fibular length. Fibular diaphyseal curvature was compared between both populations and sexes, and the correlation between fibular diaphyseal curvature with diaphyseal cross-sectional morphology and body size variables were confirmed. The results showed significant differences in the anteroposterior diaphyseal curvature between the Jomon and modern Japanese populations, and a significantly curved anterior direction was noted for Jomon males and females, compared with modern Japanese males and females. On the contrary, little populational difference was noted in terms of mediolateral diaphyseal curvature. The curvature of the fibular diaphysis showed less correlation with body size variables. Moreover, anteroposterior diaphyseal curvatures were correlated with diaphyseal robustness and had low correlation with diaphyseal shape. A relationship between anteroposterior curvature and diaphyseal cross-sectional morphology, an indicator of habitual activity, was confirmed. This suggests that the fibular curvature is possibly influenced by mechanical loading from daily activities as well.

Osteoblasts alignment and migration are involved in the directional formation of bone matrix and bone remodeling. Many studies have demonstrated that mechanical stretching controls osteoblast morphology and alignment. However, little is known about its effects on osteoblast migration. Here, we investigated changes in the morphology and migration of preosteoblastic MC3T3-E1 cells after the removal of continuous or cyclic stretching. Actin staining and time-lapse recording were performed after stretching removal. The continuous and cyclic groups showed parallel and perpendicular alignment to the stretch direction, respectively. A more elongated cell morphology was observed in the cyclic group than in the continuous group. In both stretch groups, the cells migrated in a direction roughly consistent with the cell alignment. Compared to the other groups, the cells in the cyclic group showed an increased migration velocity and were almost divided in the same direction as the alignment. To summarize, our study showed that mechanical stretching changed cell alignment and morphology in osteoblasts, which affected the direction of migration and cell division, and velocity of migration. These results suggest that mechanical stimulation may modulate the direction of bone tissue formation by inducing the directional migration and cell division of osteoblasts.

Traumatic axonal damage disrupts connections between neurons, leading to the loss of motor and sensory functions. Although damaged peripheral nerves can regenerate, recovery depends on the variety and severity of nerve damage. Thus, many phytochemicals have been studied for their ability to reduce peripheral nerve degeneration, and among them, Parthenolide (PTL), which is extracted from Feverfew has effects against production of free radicals, inflammation, and apoptosis. Thus, we conducted a study to investigate whether PTL has an inhibitory effect on peripheral nerve degeneration during peripheral nerve damage. To verify the effect of PTL on peripheral nerve degeneration process, a morphological comparison of peripheral nerves with and without PTL was performed. PTL significantly reduced the quantity of fragmented ovoid formations at 3DIV (days in vitro). Immunostaining for MBP revealed that the ratio of intact myelin sheaths increased significantly in sciatic nerve with PTL compared with absence of PTL at 3DIV. Furthermore, nerve fibers in the presence of PTL maintained the continuity of Neurofilament (NF) compared to those without at 3DIV. Immunostaining for LAMP1 and p75 NTR showed that the expression of LAMP1 and p75 NTR decreased in the nerve after PTL addition at 3DIV. Lastly, immunostaining for anti-Ki67 revealed that PTL inhibited Ki67 expression at 3DIV compared to without PTL. These results confirm that PTL inhibits peripheral nerve degenerative processes. PTL may be a good applicant to inhibit peripheral nerve degeneration. Our study examined the effect of Parthenolide in preventing degeneration of peripheral nerves by inhibiting the breakdown of peripheral axons and myelin, also inhibiting Schwann cell trans-dedifferentiation and proliferation.

White matter bundle segmentation using diffusion magnetic resonance imaging fiber tractography enables detailed evaluation of individual white matter tracts three-dimensionally, and plays a crucial role in studying human brain anatomy, function, development, and diseases. Manual extraction of streamlines utilizing a combination of the inclusion and exclusion of regions of interest can be considered the current gold standard for extracting white matter bundles from whole-brain tractograms. However, this is a time-consuming and operator-dependent process with limited reproducibility. Several automated approaches using different strategies to reconstruct the white matter tracts have been proposed to address the issues of time, labor, and reproducibility. In this review, we discuss few of the most well-validated approaches that automate white matter bundle segmentation with an end-to-end pipeline, including TRActs Constrained by UnderLying Anatomy (TRACULA), Automated Fiber Quantification, and TractSeg.

This study aimed to elucidate the origin, course, and distribution of the branches of the posterior femoral cutaneous nerve, considering the segmental and dorsoventral compositions of the sacral plexus, including the pudendal nerve. The buttocks and thighs of five cadavers were analyzed bilaterally. The branches emerged from the sacral plexus, which was divided dorsally to ventrally into the superior gluteal, inferior gluteal, common peroneal, tibial, and pudendal nerves. It descended lateral to the ischial tuberosity and comprised the thigh, gluteal, and perineal branches. As for the thigh and gluteal branches, the dorsoventral order of those originating from the sacral plexus corresponded to the lateromedial order of their distribution. However, the dorsoventral boundary was displaced at the inferior margin of the gluteus maximus between the thigh and gluteal branches. The perineal branch originated from the ventral branch of the nerve roots. In addition, the pudendal nerve branches, which ran medially to the ischial tuberosity, were distributed in the medial part of the inferior gluteal region. These branches should be distinguished from the gluteal branches; the former should be classified as the medial inferior cluneal nerves and the latter as the lateral ones. Finally, the medial part of the inferior gluteal region was distributed by branches of the dorsal sacral rami, which may correspond to the medial cluneal nerves. Thus, the composition of the posterior femoral cutaneous nerve is considered necessary when considering the dorsoventral relationships of the sacral plexus and boundaries of the dorsal and ventral rami.

Talus is a pivotal bone that assists in easy and correct locomotion and transfers body weight from the shin to the foot. Despite its small size, it is implicated in many clinical disorders. Familiarity with the anatomy of the talus and its anatomical variations is essential for the diagnosis of any disorder related to these variations. Furthermore, orthopedic surgeons must be fully aware by this anatomy during podiatry procedures. In this review, we attempt to present its anatomy in a simple, updated and comprehensive manner. We have also added the anatomical variations and some clinical points relevant to the unique and complex anatomy of talus. The talus has no muscle attachment. However, it does have many ligaments attached to it and others around it to keep it in place. Moreover, the bone plays a pig role in movements due to its involvement in many joints. Most of its surface is covered with articular cartilage. Therefore, its blood supply is relatively poor. This puts the talus at greater risk for poor healing as well as more complications in the event of injury than any other bone. We hope this review will make it easier for clinicians to pursue and understand the updated essential knowledge of one of the most complex bone anatomies that they need in their clinical practice.

The purpose of this review is to present our researches on the pelvic outlet muscles, including the pelvic floor and perineal muscles, which are responsible for urinary function, defecation, sexual function, and core stability, and to discuss the insights into the mechanism of pelvic floor stabilization based on the findings. Our studies are conducted using a combination of macroscopic examination, immunohistological analysis, 3D reconstruction, and imaging. Unlike most previous reports, this article describes not only on skeletal muscle but also on smooth muscle structures in the pelvic floor and perineum to encourage new understanding. The skeletal muscles of the pelvic outlet are continuous, which means that they share muscle bundles. They form three muscle slings that pass anterior and posterior to the anal canal, thus serving as the foundation of pelvic floor support. The smooth muscle of the pelvic outlet, in addition to forming the walls of the viscera, also extends in three dimensions. This continuous smooth muscle occupies the central region of the pelvic floor and perineum, thus revising the conventional understanding of the perineal body. At the interface between the levator ani and pelvic viscera, smooth muscle forms characteristic structures that transfer the lifting power of the levator ani to the pelvic viscera. The findings suggest new concepts of pelvic floor stabilization mechanisms, such as dynamic coordination between skeletal and smooth muscles. These two types of muscles possibly coordinate the direction and force of muscle contraction with each other.