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鈴木さんの修士論文がPLoS ONEに掲載

大腿骨の形態形成

鈴木さんの修士論文がPLoS ONEに受諾されました。

軟骨形成から軟骨内骨化の進む時期の大腿骨の形態形成について外観、内部の変化を位相CT, MRIを用いて解析しました。

  • 軟骨性大腿骨は、CS 18 で初めて観察される
  • 主要な解剖学的ランドマークは、骨化が開始する前(CRL<40mm)に形成
  • 信号強度が高い骨化の開始部位は、しだいに骨幹端軟骨板になる可能性がある骨幹端に限定される
  • 骨化部位の長さ /大腿骨の全長はCRL 40 -75 mmで急速に増加し、CRL が 75 mm で中程度に増加。
  • 軟骨管は、遠位骨端(CRL、75 mm)よりも近位骨端(CRL、62 mm)で早期に発生
  • 骨化後の大腿骨形状の変化は、初期骨化時とその前後に限定的
  • ただし、大腿骨頸部の前傾および大腿骨頭のねじれは、胎児期に連続的に変化

<修士論文の概要>

Suzuki Y, Matsubayashi J, Ji X, Yamada S, Yoneyama A, Imai H, Matsuda T, Aoyama T, Takakuwa T Morphogenesis of the femur at different stages of normal human development, PLoS ONE, 14(8): e0221569. https://doi.org/10.1371/journal. pone.0221569

Abstract

The present study aimed to better characterize the morphogenesis of the femur from the embryonic to the early fetal periods. Sixty-two human fetal specimens (crown–rump length [CRL] range: 11.4–185 mm) from the Kyoto Collection were used for this study. The morphogenesis and internal differentiation process of the femur were analyzed in 3D using phase-contrast X-ray computed tomography and magnetic resonance imaging. The cartilaginous femur was first observed at Carnegie stage 18. Major anatomical landmarks were formed prior to the initiation of ossification at the center of the diaphysis (CRL, 40 mm), as described by Bardeen. The region with very high signal intensity (phase 5 according to Streeter’s classification; i.e., area described as cartilage disintegration) emerged at the center of the diaphysis, which split the region with slightly low signal intensity (phase 4; i.e., cartilage cells of maximum size) in fetuses with a CRL of 40.0 mm. The phase 4 and phase 5 regions became confined to the metaphysis, which might become the epiphyseal cartilage plate. Femur length and ossified shaft length (OSL) showed a strong positive correlation with CRL. The OSL-to-femur length ratio rapidly increased in fetuses with CRL between 40 and 75 mm, which became moderately increased in fetuses with a CRL of ≥75 mm. Cartilage canal invasion occurred earlier at the proximal epiphysis (CRL, 62 mm) than at the distal epiphysis (CRL, 75 mm). Morphometry and Procrustes analysis indicated that changes in the femur shape after ossification were limited, which were mainly detected at the time of initial ossification and shortly after that. In contrast, femoral neck anteversion and torsion of the femoral head continuously changed during the fetal period. Our data could aid in understanding the morphogenesis of the femur and in differentiating normal and abnormal development during the early fetal period.

長田さん、八田くんの卒研がCongenital Anomaliesに受諾(2)

長田さん、八田くんの卒研の一部がCongenital Anomaliesに受諾されました。

胎児期に消化管が臍帯から腹腔に還納されるときに、回盲部がどのように移動するかを3D座標をとり検討しました。

腹腔に戻った回盲部は右下腹部にまっすぐ進んでいく

右上腹部に還納し下腹部に移動するという説も、以前は信じられていましたが、正しくないようです。

42. Nagata A, Hatta S, Imai H, Yamada S, Takakuwa T. Position of the cecum in the extraembryonic and abdominal coelom in the early fetal period. Congenit Anom 2020, 60 (3) 87-88. doi: 10.1111/cga.12348.

長田さん、八田くんの卒業論文がJ Anat に掲載

長田さん、八田くんの卒業論文がJournal of Anatomy に掲載されました。

ヒトの消化管は一時的に臍帯内に脱出しCRL40 mmころ、突然還納します(生理的ヘルニア)。生理的ヘルニアの脱出については論文がある程度ありますが、還納過程については研究がほとんどなく、不明な点が多くありました。今回の解析では、還納途中の3体を含む25体について形態計測的な検討をし以下の知見をえました。

  • 腹腔内での占拠割合は徐々に消化管が上昇、肝臓が減少し急激な変化はみられない
  • 消化管還納終了時、腹腔内で使用可能な消化管体積は200mm3で、臍帯内の最大容積25.8mmに比べ十分に大きい
  • ヘルニア期の腸管の最大の高さよりも、還納後の腹壁(臍帯輪)の高さは高い
  • 消化管還納時には、腹腔内へ張力が働く(loop model)という古典的な説に対して、
  • 腹壁がもちあがり消化管を包むことが起きている可能性を提唱(wrapping model)

35. Nagata A, Hatta S, Ji X, Ishikawa A, Sakamoto R, Yamada S, Imai H, Matsuda T, Takakuwa T. Return of the intestinal loop to the abdominal coelom after physiological umbilical herniation in the early fetal period. J Anat, 2019, 234, 456-464.doi: 10.1111/joa.12940.

Abstract

The intestine elongates during the early fetal period, herniates into the extraembryonic coelom, and subsequently returns to the abdominal coelom. The manner of herniation is well-known; however, the process by which the intestinal loop returns to the abdomen is not clear. Thus, the present study was designed to document and measure intestinal movements in the early fetal period in three dimensions to elucidate the intestinal loop return process. Magnetic resonance images from human fetuses whose intestinal loops herniated (herniated phase; n = 5) while returning to the abdominal coelom [transition phase; n = 3, crown–rump length (CRL)] 37, 41, and 43 mm] and those whose intestinal loops returned to the abdominal coelom normally (return phase; n = 12) were selected from the Kyoto Collection. Intestinal return began from proximal to distal in samples with CRL of 37 mm. Only the ileum ends were observed in the extraembryonic coelom in samples with CRLs of 41 and 43 mm, whereas the ceca were already located in the abdominal coeloms. The entire intestinal tract had returned to the abdominal coelom in samples with CRL > 43 mm. The intestinal length increased almost linearly with fetal growth irrespective of the phase (R2 = 0.90). The ratio of the intestinal length in the extraembryonic coelom to the entire intestinal length was maximal in samples with CRLs of 32 mm (77%). This ratio rapidly decreased in three of the samples that were in the transition phase. The abdominal volumes increased exponentially (to the third power) during development. The intestinal volumes accounted for 33–41% of the abdominal volumes among samples in the herniated phase. The proportion of the intestine in the abdominal cavity increased, whereas that in the liver decreased, both without any break or plateau. The amount of space available for the intestine by the end of the transition phase was approximately 200 mm3. The amount of space available for the intestine in the abdominal coelom appeared to be sufficient at the beginning of the return phase in samples with CRLs of approximately 43 mm compared with the maximum intestinal volume available for the extraembryonic coelom in the herniated phase, which was 25.8 mm3 in samples with CRLs of 32 mm. A rapid increase in the space available for the intestine in the abdominal coelom that exceeded the intestinal volume in the extraembryonic coelom generated an inward force, leading to a ‘sucked back’ mechanism acting as the driving force. The height of the hernia tip increased to 8.9 mm at a maximum fetal CRL of 37 mm. The height of the umbilical ring increased in a stepwise manner between the transition and return phases and its height in the return phase was comparable to or higher than that of the hernia tip during the herniation phase. We surmised that the space was generated in the aforementioned manner to accommodate the herniated portion of the intestine, much like the intestine wrapping into the abdominal coelom as the height of the umbilical ring increased.

石山さんの修論がPLoS Oneに掲載

石山さんの修論がPLOS ONEに受諾、掲載されました。ヒト腎臓(後腎)における尿集合管系の形成過程を明らかにし実験動物(マウス)との差異を論じました。

  • 最初の 尿路樹の分岐は CS16 で発生、CS23の最大分岐次数は12に達する、
  • 二分分岐が急速に発生し、その後ネフロンの形成が続き、CS23において末端枝数あたりの糸球体数は1.34
  • 腎盂拡張はCS23内でみられる
  • 分岐次数は極部で高い

34. Ishiyama H, Ishikawa A, Kitazawa H, Fujii S, Matsubayashi J, Yamada S, Takakuwa T, Branching morphogenesis of the urinary collecting system in the human embryonic metanephros, PLoS ONE 13(9): e0203623. https://doi.org/10.1371/journal.pone.0203623

Abstract

An elaborate system of ducts collects urine from all nephrons, and this structure is known as the urinary collecting system (UCS). This study focused on how the UCS is formed during human embryogenesis. Fifty human embryos between the Carnegie stage (CS) 14 and CS23 were selected from the Kyoto Collection at the Congenital Anomaly Research Center of Kyoto University, Japan. Metanephroses, including the UCS, were segmented on serial digital virtual histological sections. Three-dimensional images were computationally reconstructed for morphological and quantitative analyses. A CS timeline was plotted. It consisted of the 3-D structural morphogenesis of UCS and quantification of the total amount of end-branching, average and maximum numbers of generations, deviation in the metanephros, differentiation of the urothelial epithelium in the renal pelvis, and timing of the rapid expansion of the renal pelvis. The first UCS branching generation occurred by CS16. The average branching generation reached a maximum of 8.74 ± 1.60 and was already the twelfth in CS23. The total end-branching number squared between the start and the end of the embryonic period. UCS would reach the fifteenth branching generation soon after CS23. The number of nephrons per UCS end-branch was low (0.21 ± 0.14 at CS19, 1.34 ± 0.49 at CS23), indicating that the bifid branching occurred rapidly and that the formation of nephrons followed after. The renal pelvis expanded mainly in CS23, which was earlier than that reported in a previous study. The number of nephrons connected to the UCS in the expanded group (246.0 ± 13.2) was significantly larger than that of the pre-expanded group (130.8 ± 80.1) (P < 0.05). The urothelial epithelium differentiated from the zeroth to the third generations at CS23. Differentiation may have continued up until the tenth generation to allow for renal pelvis expansion. The branching speed was not uniform. There were significantly more branching generations in the polar- than in the interpolar regions (P < 0.05). Branching speed reflects the growth orientation required to form the metanephros. Further study will be necessary to understand the renal pelvis expansion mechanism in CS23. Our CS-based timeline enabled us to map UCS formation and predict functional renal capacity after differentiation and growth.

Blechschmidt collection デジタルアトラス作成の論文がCongenit Anomに掲載

Blechschmidt collectionスキャンプロジェクトについての論文がCongenital anomaliesに掲載されました。先天異常標本解析センター、ドイツ・ゲッティンゲン大学解剖学教室との共同プロジェクトです。

(ゲッティンゲン大学ヒト胚子コレクションの組織学的解析およびデジタルアトラス作成;基盤(B)(海外 )2015-2017)

  • Blechschmidt コレクションの組織標本を、市販のフラットベッド スキャナーを使用して4800 dpiの解像度画像にデジタル化
  • CRL64mm, CRL17.5mm (CS20) の2 つの標本について、最新の技術を使用して、立体再構成

⑦ Miyazaki R, Makishima H, Männer J, Sydow HG, Uwabe C, Takakuwa T, Viebahn C, Yamada S. The Blechschmidt Collection: revisiting specimens from a historical collection of serially sectioned human embryos and fetuses using modern imaging techniques, Congenit Anom, 2018, 58, 152-157, doi: 10.1111/cga.12261

ABSTRACT

Along with the Carnegie Collection in the United States and the Kyoto Collection in Japan, the Blechschmidt Collection (Georg-August-University of Göttingen, Germany) is a major historical human embryo and fetus collection. These collections are of enormous value to human embryology; however, due to the nature of the historical histological specimens, some stains are fading in color, and some glass slides are deteriorating over time. To protect these specimens against such degradation and ensure their future usefulness, we tried to apply modern image scanning and computational reconstruction. Samples of histological specimens of the Blechschmidt Collection were digitized into images using commercial flatbed scanners with a resolution of 4800 pixels per inch. Two specimens were reconstructed into three-dimensional (3D) images by using modern techniques to vertically stack two-dimensional images of the slices into 3D blocks. The larger specimen of crown-rump length (CRL) 64.0 mm, a series of very large histological sections in human embryology, was reconstructed clearly, with its central nervous system segmented before stacking. The smaller specimen of CRL 17.5 mm was also reconstructed into 3D images. The outer surface of the embryo was intact, and its development was classified according to the widely used Carnegie stages (CSs). The CS of the specimen was identified as the later half of CS 20. The invaluable Blechschmidt Collection can be revisited for further research with modern techniques such as digital image scanning and computational 3D reconstruction.

古市さんの卒論がAnat Recに掲載

古市さんの卒論がAnat Recに掲載されました。

連続組織切片の 3-D 再構成を行い、胚子期末のWillis 輪( CW )の形成を検討しました。

  • CW は胚子期末のすべての標本で閉鎖、
  • CWは単一の平面でなく、複数の階段状の平面で構成
  • 中脳と間脳の屈曲を反映してCW は尾部で急激に湾曲
  • 85%(17/20)でvariation観察
  • (anterior partのみ10例、anterior+posterior 6例、posteriorのみ1例)
  • 観察されたvariationは、胎児、新生児、成人で報告されているものと同様
  • CWのvariationが開始時期から存在することを示唆

33. Furuichi K, Ishikawa A, Uwabe C, Makishima H, Yamada S, Takakuwa T,
Variations of the circle of Willis at the end of the human embryonic period,  2018, 301, 1312-1319, doi:10.1002/ar.23794

ABSTRACT

Variations of the circle of Willis (CW) influence blood supply to the brain and adjacent structures in adults. We examined the formation of the CW in 20 human embryo samples at the end of the embryonic period using 3-D reconstructions of serial histological sections. The CW was closed in all samples, and did not form in a single plane, but was composed of multiple stair-like planes. The artery acutely curved at the caudal part of the CW, namely, at the inlet of the basilar artery and bifurcation of the P1 segment of the posterior cerebral artery (PCA), reflecting flexure of the mesencephalon and diencephalon at this stage. Variations were observed in 17 of 20 samples—only anterior parts (anterior communicating artery [Acom] and anterior cerebral artery [ACA]) in 10 samples, only posterior parts (posterior communicating artery [Pcom]) in one sample, and both anterior and posterior parts in six samples. Variations included the Acom formed as partially duplicated in three samples, duplicated in four, plexiform in three, and no channel as a result of a single azygos ACA in one. The ACA formed as duplicated in two, median ACA in two, and right hypoplasia in one. The Pcom formed in hypoplasia of either side in six samples. Variations observed in this study are similar to those observed in fetuses, neonates, and adults. The P1 segment of PCA was very large in all samples. The present observations indicate that variations in the CW are present from the initiation of CW formation.

先天研開設40周年記念号がAnat Recから発刊

先天研開設40周年記念号がAnatomical Recに掲載されました。

先天研開設40周年記念号;ヒト胚子・胎児研究についての総説 Anat Rec 2018, 301,960-969 (クリックで拡大されます)

金橋君が日本先天異常学会奨励賞を受賞しました

金橋君が2018年度日本先天異常学会奨励賞を受賞しました。おめでとうございます。

Kanahashi T, Yamada S, Tanaka M, Hirose A, Uwabe C, Kose K, Yoneyama A, Takeda T, Takakuwa T, A novel strategy to reveal the latent abnormalities in human embryonic stages from a large embryo collection, Anatomical Record, 299,8-24,2016  10.1002/ar.23281(概要), *299(1),2016の表紙に採用されました。DOI: 10.1002/ar.23206 (cover page)