1.Site-dependent differences and common features of lymph node architecture, with special reference to the distribution of nodal dendritic cells and macrophages: a cadaveric study
Eri MIYAMOTO ; Masaya AOKI ; Kei KITAMURA ; Ryo SEKIYA ; Kazuma MORITA ; Gen MURAKAMI ; Shinichi ABE
Anatomy & Cell Biology 2025;58(4):528-543
Although human lymph node architecture varies by site, the intranodal distribution of interdigitating dendritic cells (DCs) remains poorly understood. To address this, we compared the morphology of submandibular, paratracheal, mesenteric, and inguinal nodes obtained from 24 donated cadavers. Immunoreactivity was evaluated by comparing these cadaveric nodes with surgically resected lymph nodes obtained from five old-aged patients with nonmetastatic cancer.Despite the limited number of dendritic cell-specific ICAM-3–grabbing nonintegrin (DC-SIGN)–positive cells (candidate DCs) in cadaveric specimens, these tissues were deemed suitable for analysis. The submandibular and paratracheal nodes exhibited a belt-like cortex, with paracortical lymph sinus extending from the subcapsular sinus and surrounding the follicle.In contrast, the mesenteric and inguinal nodes contained multiple island-like cortices separated by thick paracortical lymph sinuses. Endothelial cells lining all lymph sinuses showed reactivity for smooth muscle actin and DC-SIGN. Macrophages and candidate DCs were abundant in the paratracheal and mesenteric node sinuses but scarce in the submandibular and inguinal nodes. Notably, the medullary sinus in the submandibular and inguinal nodes was filled with fibrous tissue, and the surrounding paracortical sinuses formed a “sea” around the island-like cortices, often resulting in loss of nodal polarization.Although the proportional area occupied by candidate DCs per nodal section was almost the same at the four sites, the overlap between DCs and macrophage clusters was small in paratracheal and inguinal nodes. The amount of afferent lymph and the retention of efferent lymph might determine the site-dependent architecture. Therefore, in aged nodes, DCs were preferentially localized in the paracortical sinus.
2.Junction between membranous and endochondral bones in the developing occipital squamosa
Kotoko IMAI ; Kei KITAMURA ; Ryo SEKIYA ; Kazuma MORITA ; Sakiko TAKAHASHI ; Gen MURAKAMI ; Jose Francisco RODRÍGUEZ-VÁZQUEZ ; Shinichi ABE
Anatomy & Cell Biology 2025;58(4):570-580
The occipital bone squamosa (OCS) is unique because of its double origin from both endochondral and membranous bones. The present study attempted to demonstrate the process of connection between these two bone types. We examined sagittal and frontal histological sections from 29 human fetuses with a crown-rump length ranging from 38 to 328 mm (approximately 7–39 weeks of gestational age [GA]). An initial cartilage plate appeared in the posterior side of the fourth ventricle at GA 7–8 weeks and extended inferiorly to connect with the cartilaginous basioccipital and condyle. At GA 9–10 weeks, on the superior side of the cartilage plate, membranous bone fragments appeared and adopted an arrangement resembling a chain of irregularly-shaped beads.They did not form a complete plate-like bone until late-term. At GA 11–12 weeks, endochondral ossification centers appeared at the upper and lower ends of the cartilage plate. At GA 12–15 weeks, a bar-like periosteal bone developed near and superior to the upper ossification center. Notably, sinusoidal structures, which were surrounded by growing periosteal bones, contained islandlike clusters of calcified cartilage fragments. Therefore, the upper ossification center appeared likely to “migrate” downward and become distant from membranous bones. The extending periosteal bone reached and joined the membranous bone fragments.Consequently, the periosteal bones connected between the endochondral and membranous bones in the OCS. This connection was quite different from the other components of the calvaria, where membranous bones overlap the skull base cartilages at the margin.
3.Distally-extending muscle fibers across involved joints: study of long muscles and tendons of wrist and ankle in late-term fetuses and adult cadavers
Shaohe WANG ; Shogo HAYASHI ; Zhe-Wu JIN ; Ji Hyun KIM ; Masahito YAMAMOTO ; Gen MURAKAMI ; Shinichi ABE
Anatomy & Cell Biology 2023;56(1):46-53
It is unclear whether forearm and crural muscle fibers extend distally across the wrist and ankle joints, respectively.We hypothesized, in late-term fetuses, an over-production of muscle bellies extending over the joint. Muscle fibers in histological sections from unilateral wrists and ankles of 16 late-term fetuses (30–40 weeks) were examined and compared with 15 adult cadavers. Muscle fibers of the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) in fetuses, especially muscle bellies to the third and fourth fingers, were found to extend far distally beyond the radiocarpal joint.The extensor digitorum and extensor pollicis longus on the extensor side of the wrist were found to carry distally-extending muscle fibers, but these fibers did not extend beyond the distal end of the radius. In the ankle, most muscle bundles in the flexor hallucis longus (FHL), fibularis brevis (FB) and extensor digitorum longus extended distally beyond the talocrural joint, with most FB muscle fibers reaching the level of the talocalcaneal joint. In adult cadavers, muscle fibers of the FDP and FHL did not reach the levels of the radiocarpal and talocrural joints, respectively, whereas the FB muscle belly always reached the talocalcaneal joint. Similarly, some of the FDS reached the level of the radiocarpal joint. Generally, infants’ movements at the wrist and ankle could result in friction injury to over-extended muscle. However, the calcaneal and FDP tendons might protect the FB and FDS tendons, respectively, from friction stress.
4.A Case Report of a Patient who Achieved Recovery of Walking Independence with the Adjustment of the Prosthesis after Bilateral Leg Amputation and Spinal Cord Injury.
Masamune EBARA ; Rina ABE ; Dai FUJIWARA ; Kentaro KANARI ; Tsuyoshi MIZUSHIRI ; Shinichi IZUMI
The Japanese Journal of Rehabilitation Medicine 2023;():23025-
This report describes a case of an amputee with a lumber spinal cord injury who successfully recovered ambulation with the use of prosthesis.A 30-year-old man with schizophrenia underwent amputation of the lower legs and concurrently developed lumbar spinal cord injury from of a suicide attempt. After the treatment of stump plasty and posterior fusion, the patient was transferred to our facility. Lower-extremity prostheses for both legs were fitted, and orthostatic training was commenced following admission. During the initial evaluation, the patient could not maintain a stable standing position because of weakness in the hip extensor muscle. An inflexion angle of the prosthesis was set to 0° to extend the knee joint and achieve standing stability. Appropriate adjustments of the prosthesis were made as required, specifically addressing the paraplegia caused by his lumbar spinal cord injury. Thus, the patient successfully regained ambulation with the treatment.Recovering walking independence after bilateral lower leg amputations or paraplegia caused by lumber spinal cord injury is not uncommon. However, this case is unique in that the muscle weakness caused by lumbar spinal cord injury presented unforeseen difficulties for the patient to achieve ambulation, which is not ordinarily observed in amputation rehabilitation cases. No similar cases have been reported in which patients concurrently suffered from both these conditions in Japan;therefore, this case is extremely rare.
5.A Case Report of a Patient who Achieved Recovery of Walking Independence with the Adjustment of the Prosthesis after Bilateral Leg Amputation and Spinal Cord Injury.
Masamune EBARA ; Rina ABE ; Dai FUJIWARA ; Kentaro KANARI ; Tsuyoshi MIZUSHIRI ; Shinichi IZUMI
The Japanese Journal of Rehabilitation Medicine 2023;60(9):799-804
This report describes a case of an amputee with a lumber spinal cord injury who successfully recovered ambulation with the use of prosthesis.A 30-year-old man with schizophrenia underwent amputation of the lower legs and concurrently developed lumbar spinal cord injury from of a suicide attempt. After the treatment of stump plasty and posterior fusion, the patient was transferred to our facility. Lower-extremity prostheses for both legs were fitted, and orthostatic training was commenced following admission. During the initial evaluation, the patient could not maintain a stable standing position because of weakness in the hip extensor muscle. An inflexion angle of the prosthesis was set to 0° to extend the knee joint and achieve standing stability. Appropriate adjustments of the prosthesis were made as required, specifically addressing the paraplegia caused by his lumbar spinal cord injury. Thus, the patient successfully regained ambulation with the treatment.Recovering walking independence after bilateral lower leg amputations or paraplegia caused by lumber spinal cord injury is not uncommon. However, this case is unique in that the muscle weakness caused by lumbar spinal cord injury presented unforeseen difficulties for the patient to achieve ambulation, which is not ordinarily observed in amputation rehabilitation cases. No similar cases have been reported in which patients concurrently suffered from both these conditions in Japan;therefore, this case is extremely rare.
6.Current Status of Cardiovascular Surgery in Japan : A Report Based on the Japan Cardiovascular Surgery Database in 2017, 2018 3. Valvular Heart Surgery
Tomonobu ABE ; Hiraku KUMAMARU ; Kiyoharu NAKANO ; Noboru MOTOMURA ; Hiroaki MIYATA ; Shinichi TAKAMOTO
Japanese Journal of Cardiovascular Surgery 2020;49(4):160-168
Objectives : We sought to present data relative to valvular heart surgeries from the Japan Cardiovascular Surgery Database in 2017 and 2018 to show current status and trend in Japan. Methods : We extracted data relative to cardiac valve surgeries performed in 2017 and 2018 from the Japan Cardiovascular Surgery Database. We obtained total number of aortic valve replacement procedures and showed trend for these 6 years from 2013 to 2018. The operative mortality rates were shown for representative valve procedures stratified by age group with the aim of showing a bench mark of Japan. Data regarding minimally invasive procedures and transcatheter aortic valve implantation which the Japan Cardiovascular Surgery Database can provide were also presented. Results : Despite dramatic increase of number of transcatheter aortic valve implantation in 2017 and 2018 compared to in 2015 and 2016, surgical aortic valve replacement also increased from 26,054 to 28,202. Regarding the operative mortality of first time valve procedures, it was 1.8% in isolated aortic valve replacement, 0.9% in isolated mitral valve repair, 8.2% in mitral valve replacement with biological prostheses, and 4.6% with mechanical prostheses. For first time valve procedures with concomitant coronary artery bypass, the operative mortality was 5.2% in aortic valve replacement, 4.9% in mitral valve repair. Regarding prosthetic valve selection, 72.6% of patients had biological prosthesis for aortic valve replacement procedures in their 60's, showing trend of increasing percentages of biological valve choice. Regarding minimally invasive procedure, 31.8% of first time isolated mitral valve plasty were performed via right thoracotomy. Though patients who underwent surgery via right thoracotomy had better clinical outcomes, it was also apparent that the patients who underwent surgery via right thoracotomy had lower operative risk profile. Aortic clamp time and cardiopulmonary bypass time were longer in the right thoracotomy patients. 6.3% of the patients who had isolated aortic valve replacement underwent surgery via right thoracotomy. The right thoracotomy aortic valve replacement patients had better clinical outcomes and had more percentage of lower risk profile. The overall mortality of transcatheter aortic valve implantation and surgical aortic valve replacement were 1.5% and 1.8%, respectively. Conclusion : We reported data related to heart valve surgery in 2017 and 2018 from the Japan Cardiovascular Surgery Database.
7.Analgesic effects and distribution of cutaneous sensory blockade of quadratus lumborum block type 2 and posterior transversus abdominis plane block: an observational comparative study
Yuki AOYAMA ; Shinichi SAKURA ; Shoko ABE ; Minori WADA ; Yoji SAITO
Korean Journal of Anesthesiology 2020;73(4):326-333
Background:
The posterior transversus abdominis plane block (TAPB) and quadratus lumborum block (QLB) were developed for postoperative pain control after lower abdominal surgery. However, there is little data regarding their effects. Their analgesic effects and the distribution of the cutaneous sensory blockade were observed in patients undergoing laparoscopic gynecologic surgery.
Methods:
After an induction of general anesthesia, patients alternately received bilateral ultrasound-guided QLB type 2 (QLB2) or posterior TAPB using 20 ml of 0.375% levobupivacaine on each side. The measurements included visual analogue pain scores (VAS), cutaneous sensory blockade in each dermatome, demands for postoperative analgesics, and complications for up to 48 h after the block. Our primary endpoint was VAS at 24 h after the block.
Results:
Forty patients completed the study. The VAS at rest was significantly lower after QLB2 than that after TAPB at 48 h, but not at 24 h. Neither group differed in VAS when coughing at any point in time. Postoperative demands for fentanyl and other analgesics also did not differ for either block. The majority of injections produced a cutaneous sensory blockade in the T11 and T12 dermatomes in both groups. The median number of dermatomes blocked was limited to three dermatomes after either block. No severe complication related to either block was observed.
Conclusions
The analgesic effects of QLB2 and posterior TAPB did not differ in patients undergoing laparoscopic gynecologic surgery. The cutaneous sensory blockade produced was limited to three dermatomal levels in the majority of patients. However, these findings need to be confirmed through a larger comparative study.
8.Fetal development of the human trapezius and sternocleidomastoid muscles
Kwang Ho CHO ; Ichiro MORIMOTO ; Masahito YAMAMOTO ; Shinya HANADA ; Gen MURAKAMI ; Jose Francisco RODRÍGUEZ-VÁZQUEZ ; Shinichi ABE
Anatomy & Cell Biology 2020;53(4):405-410
At present, there is no photographic evidence of splitting of the trapezius and sternocleidomastoid muscles (SCMs), which share a common anlage that extends caudally toward the limb bud in the embryo at a length of 9 mm. Therefore, the aim of the present study was to identify which structures divide the caudal end of the common anlage at the first sign of splitting into two muscles. In 11 mm-long specimens, the SCM and trapezius muscles were identified as a single mesenchymal condensation. In 15 and 18 mm-long specimens, the SCM and trapezius muscles were separated and extended posteriorly and lymphatic tissues appeared in a primitive lateral cervical space surrounded by the SCM (anterior). In 21 mm-long specimens, the lymphatic vessels were dilated and the accompanying afferents were forming connections with the subcutaneous tissue through a space between the SCM and trapezius muscles. In 27 mm-long specimens, cutaneous lymphatic vessels were evident and had entered the deep tissue between the SCM and trapezius muscles. Vascular dilation may be viewed as a result of less mechanical stress or pressure after muscle splitting.
9.Cervical nerve roots and the dural sheath: a histological study using human fetuses near term
Kei KITAMURA ; Masahito YAMAMOTO ; Yoshinosuke HIROTA ; Noriyuki SATO ; Toshimasa MACHIDA ; Noboru ISHIKAWA ; Hitoshi YAMAMOTO ; Gen MURAKAMI ; Shinichi ABE
Anatomy & Cell Biology 2020;53(4):451-459
We have previously reported that the thoracolumbar posterior nerve root shows a tortuous epidural course, based on studies of human fetuses near term. For comparison with the cervical nerve, examinations were conducted using frontal, sagittal and horizontal sections of cervical vertebrae from 22 fetuses at 30–38 weeks of gestation. The cervical nerve root showed a short, straight and lateral course near the zygapophysial joint. Multiple rather than single bundles of the cervical posterior root seemed to account for the majority of sensory nerve fibers innervating the upper extremity. Fasciculation of rootlets was evident near the thoracolumbar spinal cord, whereas it was seen in the dural pocket at the nerve exit from the dural sac although both sites were subdural. As in the thoracolumbar region, the nerve sheath was continuous with the dura mater and independently surrounded each of the anterior and posterior roots. Radicular arteries were few in the cervical region. In 2 of the 22 fetuses (31 weeks and 33 weeks), there was a segmental, unilateral abnormality of nerve rootlet fasciculation where the dorsal root ganglion was located lateral or peripheral to the intervertebral region. Long nerve roots running inferiorly are a necessary adaptation to the delayed and marked growth of the thoracolumbar vertebral column.In children, the cervical nerve roots are likely to be affected by movement or dislocation of the vertebrae. The segmental abnormality of the cervical nerve root may be linked to rare variations in the brachial plexus.
10.Retromandibular vein position and course patterns in relation to mandible: anatomical morphologies requiring particular vigilance during sagittal split ramus osteotomy
Keisuke SUGAHARA ; Satoru MATSUNAGA ; Masahito YAMAMOTO ; Taku NOGUCHI ; Sumiharu MORITA ; Masahide KOYACHI ; Yu KOYAMA ; Takumi KOYAMA ; Norio KASAHARA ; Shinichi ABE ; Akira KATAKURA
Anatomy & Cell Biology 2020;53(4):444-450
Major bleeding associated with sagittal split ramus osteotomy (SSRO) involves vessels such as the inferior alveolar, facial, and maxillary arteries and veins, and the retromandibular vein (RMV). The present study aimed to clarify and classify the three-dimensional variations in RMV position and course direction in relation to the mandible. Specimens comprised a total of 15 scientific cadavers, and the relationship between RMV and the mandible lateral and posterior views was observed.We identified 3 patterns on the lateral view, the mean distance between the RMV and the posterior border of the ramus was 3.9 mm at the height of the lingula. A total of five course patterns were identified on the posterior view. In no course pattern, the RMV inferior to the lingula was lateral to its position superior to the lingual. The present findings suggest that it may be possible to predict correlations with intraoperative bleeding risk. Further study is planned using contrast computed tomography in patients with jaw deformity for skeletal classification.


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