Current knowledge about human development is based on the description of a limited number of embryonic specimens published in original articles and textbooks, often more than 100 years ago. It is exceedingly difficult to verify this knowledge, given the restricted availability of human embryos. We created a three-dimensional digital atlas and database spanning the first 2 months of human development, based on analysis of nearly 15,000 histological sections of the renowned Carnegie Collection of human embryonic specimens. We identified and labeled up to 150 organs and structures per specimen and made three-dimensional models to quantify growth, establish changes in the position of organs, and clarify current ambiguities. The atlas provides an educational and reference resource for studies on early human development, growth, and congenital malformations.
Background: Delayed gastric emptying (DGE) is a major problem after pancreatoduodenectomy (PD). A recent multicentre randomized trial reported no difference in gastric emptying rates between retrocolic and antecolic reconstruction routes. The present study looked at quality of life with these two approaches and the correlation with gastric emptying. Results: There were 38 patients in the retrocolic and 35 in the antecolic group. Baseline characteristics and clinical outcomes were similar in the two groups. Median time to half-emptying of stomach content after surgery was 145 and 64 min in the retrocolic and antecolic group respectively (P = 0⋅189). Median percentages of residual activity after 2 h were 64 and 28 per cent respectively (P = 0⋅213). Quality of life did not differ at any time point between the groups. At 2 weeks after surgery, patients with DGE had significantly worse outcomes on two EQ-5D™ domains, ten QLQ-C30/PAN26 subscales, and two GIQLI subscales and total score. Effect sizes were moderate to large. Conclusion:The route of gastroenteric reconstruction after PD does not influence either gastric emptying at scintigraphy or quality of life. The impact of DGE on quality of life is clinically significant. Registration number NTR1697 (www.trialregister.nl).
The notochord is a major regulator of embryonic patterning in vertebrates and abnormal notochordal development is associated with a variety of birth defects in man. Proper knowledge of the development of the human notochord, therefore, is important to understand the pathogenesis of these birth defects. Textbook descriptions vary significantly and seem to be derived from both human and animal data whereas the lack of references hampers verification of the presented data. Therefore, a verifiable and comprehensive description of the development of the human notochord is needed. Our analysis and three-dimensional (3D) reconstructions of 27 sectioned human embryos ranging from Carnegie Stage 8 to 15 (17–41 days of development), resulted in a comprehensive and verifiable new model of notochordal development. Subsequent to gastrulation, a transient group of cells briefly persists as the notochordal process which is incorporated into the endodermal roof of the gut while its dorsal side attaches to the developing neural tube. Then, the notochordal process embeds entirely into the endoderm, forming the epithelial notochordal plate, which remains intimately associated with the neural tube. Subsequently, the notochordal cells detach from the endoderm to form the definitive notochord, allowing the paired dorsal aortae to fuse between the notochord and the gut. We show that the formation of the notochordal process and plate proceeds in cranio-caudal direction. Moreover, in contrast to descriptions in the modern textbooks, we report that the formation of the definitive notochord in humans starts in the middle of the embryo, and proceeds in both cranial and caudal directions.
Adult hepatoblastoma (AHB) is a rare liver tumor with a poor prognosis in adolescents and adults. This contrasts with hepatoblastoma in children and is not fully understood. Here we describe two adolescents with AHB who were treated in our hospital. Adolescents are likely to receive less intensive chemotherapy protocols and are treated in hospitals with less experience in pediatric oncology, resulting in poor outcome. More research is necessary for optimal treatment of AHB in adolescents. Adolescents with AHB should be referred to hospitals experienced in pediatric oncology and receive intensive chemotherapy, followed by hemihepatectomy.
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