Evolution of the regulation of developmental gene expression in blind Mexican cavefish.

Developmental evolution and diversification of morphology can arise through changes in the regulation of gene expression or protein-coding sequence. To unravel mechanisms underlying early developmental evolution in cavefish of the species Astyanax mexicanus, we compared transcriptomes of surface-dwelling and blind cave-adapted morphs at the end of gastrulation. Twenty percent of the transcriptome was differentially expressed. Allelic expression ratios in cave X surface hybrids showed that cis-regulatory changes are the quasi-exclusive contributors to inter-morph variations in gene expression. Among a list of 108 genes with change at the cis-regulatory level, we explored the control of expression of rx3, a master eye gene. We discovered that cellular rx3 levels are cis-regulated in a cell-autonomous manner, whereas rx3 domain size depends on non-autonomous Wnt and Bmp signalling. These results highlight how uncoupled mechanisms and regulatory modules control developmental gene expression and shape morphological changes. Finally, a transcriptome-wide search for fixed coding mutations and differential exon usage suggested that variations in coding sequence have a minor contribution. Thus, during early embryogenesis, changes in gene expression regulation are the main drivers of cavefish developmental evolution.

Apomixis beyond trees in the Brazilian savanna: new insights from the orchid Zygopetalum mackayi.

n the Neotropics, the focus of apomictic studies predominantly centres on trees within the Brazilian savanna, characterized, mostly as sporophytic and facultative, associated with polyploidy and polyembryony. To enhance our understanding of the mechanisms governing apomixis and sexual reproduction in tropical herbaceous plants, we clarify the relationship between apomixis, chromosome counts, and polyembryony in the epiphytic orchid Zygopetalum mackayi, which forms a polyploid complex within rocky outcrops in both the Brazilian savanna and the Atlantic forest. To define embryo origins and describe megasporogenesis and megagametogenesis, we performed manual self-pollinations in first-day flowers of cultivated plants, considering all three cytotypes (2x, 3x, 4x) of this species. Flowers and fruits at different stages were collected to describe the development and morphology of ovules and seeds considering sexual and apomictic processes. As self-pollination treatments resulted in high fruit abortion in diploids, we also examined pollen tube development in aborted flowers and fruits to search for putative anomalies. Megasporogenesis and megagametogenesis occur regularly in all cytotypes. Apomixis is facultative and sporophytic, and associated with polyploid cytotypes, while diploid individuals exclusively engage in sexual reproduction. Polyembryony is caused mainly by the production of adventitious embryos from nucellar cells of triploids and tetraploids, but also by the development of multiple archesporia in all cytotypes. Like other apomictic angiosperms within the Brazilian savanna, our findings demonstrate that apomixis in Z. mackayi relies on pollinators for seed production. We also consider the ecological implications of these apomictic patterns in Z. mackayi within the context of habitat loss and its dependence on pollinators.

Fluid-Dynamic Modeling of Flow in Embryonic Tissue Indicates That Lymphatic Valve Location Is Not Consistently Determined by the Local Fluid Shear or Its Gradient.

OBJECTIVE: Intravascular lymphatic valves often occur in proximity to vessel junctions. It is commonly held that disturbed flow at junctions is responsible for accumulation of valve-forming cells (VFCs) at these locations as the initial step in valve creation, and the one which explains the association with these sites. However, evidence in favor is largely limited to cell culture experiments. METHODS: We acquired images of embryonic lymphatic vascular networks from day E16.5, when VFC accumulation has started but the developing valve has not yet altered the local vessel geometry, stained for Prox1, which co-localizes with Foxc2. Using finite-element computational fluid mechanics, we simulated the flow through the networks, under conditions appropriate to this early development stage. Then we correlated the Prox1 distributions with the distributions of simulated fluid shear and shear stress gradient. RESULTS: Across a total of 16 image sets, no consistent correlation was found between Prox1 distribution and the local magnitude of fluid shear, or its positive or negative gradient. CONCLUSIONS: This, the first direct semi-empirical test of the localization hypothesis to interrogate the tissue from in vivo at the critical moment of development, does not support the idea that a feature of the local flow determines valve localization.

scRNA-seq reveals the diversity of the developing cardiac cell lineage and molecular players in heart rhythm regulation.

We utilized scRNA-seq to delineate the diversity of cell types in the zebrafish heart. Transcriptome profiling of over 50,000 cells at 48 and 72 hpf defined at least 18 discrete cell lineages of the developing heart. Utilizing well-established gene signatures, we identified a population of cells likely to be the primary pacemaker and characterized the transcriptome profile defining this critical cell type. Two previously uncharacterized genes, atp1b3b and colec10, were found to be enriched in the sinoatrial cardiomyocytes. CRISPR/Cas9-mediated knockout of these two genes significantly reduced heart rate, implicating their role in cardiac development and conduction. Additionally, we describe other cardiac cell lineages, including the endothelial and neural cells, providing their expression profiles as a resource. Our results established a detailed atlas of the developing heart, providing valuable insights into cellular and molecular mechanisms, and pinpointed potential new players in heart rhythm regulation.

Atypical telencephalic reflux pattern in a cavernous sinus dural AV fistula related to an anatomical variation of the basal vein of Rosenthal.

Cavernous sinus dural arteriovenous fistula can cause cerebral edema and hemorrhage due to cortical venous reflux and congestion. Understanding complex venous reflux and drainage routes is crucial for treatment planning. Here, we present a case of a cavernous sinus dural arteriovenous fistula with cortical venous reflux via two separate terminations of the telencephalic veins caused by an aplastic basal vein of Rosenthal. The patient presented with diplopia and eye redness and was diagnosed with a Cognard type IIa + b cavernous sinus dural arteriovenous fistula. The shunt was supplied by the dural branches of the internal and external carotid arteries. Multiple shunt points involving the intercavernous sinus and the medial aspect of the left cavernous sinus were identified, with drainage into the supraorbital and intracranial veins, including two separate terminations of the telencephalic veins, one leading to the laterocavernous sinus via the superficial middle cerebral vein and the other to the cavernous sinus via the uncal vein, resulting in basal ganglia venous congestion in the absence of the basal vein of Rosenthal. During transvenous embolization, the intracranial veins, cavernous sinus, and intercavernous sinus were obliterated using a double-catheter technique with a combination of coils and liquid embolics. Telencephalic venous variations can lead to cavernous sinus drainage into the basal ganglia and orbitofrontal brain. This unique drainage pattern underscores the importance of recognizing anatomical variations when managing cavernous sinus dural arteriovenous fistula.

Embryo sac cellularization defects lead to supernumerary egg cells and twin embryos in Arabidopsis thaliana.

Arabidopsis lines with loss-of-function mutation in Embryo sac-specific Pectin MethylEsterase Inhibitor (Atepmei) gene showed seed sterility with embryo sac cellularization defects. Examination of tissue-cleared mature ovules revealed irregularly positioned nuclei/embryos within the embryo sacs. Egg cell-specific marker (DD45) expression analysis confirmed the presence of multiple egg cells in the mutant embryo sacs. These supernumerary egg cells were functional as evident from the production of twin embryos when supernumerary sperm cells were provided. The results of ruthenium red and tannic acid-ferric chloride staining of developing Atepmei mutant ovules showed that cell wall formation and maintenance were altered around embryo sac nuclei, which also coincided with change in the gamete specification. This report implicates the role of cell walls in gamete cell fate determination by altering cell-cell communication. Our analysis of the twin-embryo phenotype of epmei mutants also sheds light on the boundary conditions for double fertilization in plant reproduction.

Fetal development of the urinary tract of Cuniculus paca.

The species Cuniculus paca is highly subject to predation, whether natural or anthropogenic, and the ability of species to withstand different levels of depredation depends directly on their reproductive dynamics. However, there is little literature on the developmental biology of this species, and so the aim of this paper was to describe the fetal development of the urinary tract of C. paca through morphological analysis. Twelve specimens with estimated gestational ages of between 75 and 157 days were used, divided into 3 groups. We found the urinary tract in pelvic-abdominal topography with macroscopic differentiation between the organs already present in the first ages studied; in addition, the microscopic structural pattern changed little between the groups. This evidence reinforces the precocial development of these individuals. RESEARCH HIGHLIGHTS: With the results obtained for development of urinary tract in Cuniculus paca reinforces the precocial development of these individuals. The urinary tract had pelvic-abdominal topography with macroscopic differentiation between the organs already present in the first ages studied. The microscopic structural pattern changed little between the groups. At all analyzed fetal ages, the cortical region of kidney was characterized by the presence of glomeruli arranged throughout the region, formed by capillary plexuses surrounded by a glomerular capsule. In addition, the cortical region also presented convoluted tubules with cubic epithelial tissue cells and a brush border. The presence of a developed macula densa was observed next to the glomeruli, suggesting the initial formation of the fetal juxtaglomerular apparatus.

Integrative analysis of Lunatic Fringe variants associated with spondylocostal dysostosis type-III.

Lunatic Fringe (LFNG) is required for spinal development. Biallelic pathogenic variants cause spondylocostal dysostosis type-III (SCD3), a rare disease generally characterized by malformed, asymmetrical, and attenuated development of the vertebral column and ribs. However, a variety of SCD3 cases reported have presented with additional features such as auditory alterations and digit abnormalities. There has yet to be a single, comprehensive, functional evaluation of causative LFNG variants and such analyses could unveil molecular mechanisms for phenotypic variability in SCD3. Therefore, nine LFNG missense variants associated with SCD3, c.564C>A, c.583T>C, c.842C>A, c.467T>G, c.856C>T, c.601G>A, c.446C>T, c.521G>A, and c.766G>A, were assessed in vitro for subcellular localization and protein processing. Glycosyltransferase activity was quantified for the first time in the c.583T>C, c.842C>A, and c.446C>T variants. Primarily, our results are the first to satisfy American College of Medical Genetics and Genomics PS3 criteria (functional evidence via well-established assay) for the pathogenicity of c.583T>C, c.842C>A, and c.446C>T, and replicate this evidence for the remaining six variants. Secondly, this work indicates that all variants that prevent Golgi localization also lead to impaired protein processing. It appears that the FRINGE domain is responsible for this phenomenon. Thirdly, our data suggests that variant proximity to the catalytic residue may influence whether LFNG is improperly trafficked and/or enzymatically dysfunctional. Finally, the phenotype of the axial skeleton, but not elsewhere, may be modulated in a variant-specific fashion. More reports are needed to continue testing this hypothesis. We anticipate our data will be used as a basis for discussion of genotype-phenotype correlations in SCD3.

Integrated Case-Based Learning Session for Breast and Upper Limb Anatomy.

Introduction: Medical students are frequently introduced to medical school curricula through anatomy coursework, which often includes histology and embryology content. As medical education has increasingly emphasized integration of content areas, use of activities such as case-based learning (CBL) sessions has grown. Little published work has demonstrated the effectiveness of CBL sessions in integrating anatomy, embryology, and histology on first-year medical students' ability to improve content mastery and adapt their study techniques. Methods: We developed a CBL session that included anatomy, embryology, and histology content covering the upper extremity and breast pathology that was taught to incoming first-year medical students (N = 51) during a prematriculation program in the summers of 2022 and 2023. The session involved completion of an individual pre- and postsession quiz; group completion of clinical cases involving image interpretation, matching exercises, and construction of diagrams, flowcharts, or tables; and a postsession survey with Likert-style and free-response questions about preparation and session effectiveness. Results: Postsession quiz scores significantly improved (p < .001). On the postsession survey (response rate: 59%), students commented that they enjoyed the real-life application and integration of the cases and that the sessions improved their understanding of the connections between content areas. Other comments demonstrated that students were evaluating and adapting their study approach in preparation for the sessions, often using techniques introduced and practiced in the sessions. Discussion: CBL sessions can provide opportunities to incoming first-year medical students to practice, adapt, and evaluate study techniques while delivering integrated content.

Introducing AnatomyGPT: A customized artificial intelligence application for anatomical sciences education.

Artificial intelligence (AI) technologies are poised to become an increasingly important part of education in the anatomical sciences. OpenAI has also introduced generative pretrained transformers (GPTs), which are customizable versions of the standard ChatGPT application. There is little research that has explored the potential of GPTs to serve as intelligent tutoring systems for learning the anatomical sciences. The objective of this study was to describe the design and explore the performance of AnatomyGPT, a customized artificial intelligence application intended for anatomical sciences education. The AnatomyGPT application was configured with GPT Builder by uploading open-source textbooks as knowledge sources and by providing pedagogical instructions for how to interact with users. The performance of AnatomyGPT was compared with ChatGPT by evaluating the responses of both applications to prompts of the National Board of Medical Examiners (NBME) sample items with respect to accuracy, rationales, and citations. AnatomyGPT achieved high scores on the NBME sample items for Gross Anatomy, Embryology, Histology, and Neuroscience and scored comparably to ChatGPT. In addition, AnatomyGPT provided several citations in the responses that it generated, while ChatGPT provided none. Both GPTs provided rationales for all sample items. The customized AnatomyGPT application demonstrated preliminary potential as an intelligent tutoring system by generating responses with increased citations as compared with the standard ChatGPT application. The findings of this study suggest that instructors and students may wish to create their own custom GPTs for teaching and learning anatomy. Future research is needed to further develop and characterize the potential of GPTs for anatomy education.

An Extensive Study Regarding the Microscopic Anatomy of the Early Fetal Human Optic Nerve.

The development of the optic nerve and its surrounding tissues during the early fetal period is a convoluted period because it spans both the organogenesis period and the fetal period. This study details the microscopic anatomy and histoembryology of the optic nerve in embryos during the early fetal period, including the second half of the first trimester of pregnancy. Serial sections through the orbit of variously aged embryos allowed us to analyze the nerve in both longitudinal and transverse aspects. A histological assessment and description of the structures surrounding and inside the nerve were performed, highlighting the cellular subtypes involved. By employing immunohistochemical techniques, we could characterize the presence and distribution of astrocytes within the optic nerve. Our findings suggest that by the 8th gestational week (WG) the structures are homologs to all the adult ones but with an early appearance so that maturation processes take place afterward. By this age, the axons forming the nerve are definitive adult axons. The glial cells do not yet exhibit adult phenotype, but their aspect becomes adult toward the 13th week. During its development the optic nerve increases in size then, at 14 weeks, it shrinks considerably, possibly through its neural maturation process. The morphological primordium of the blood-nerve barrier can be first noted at 10 WG and at 13 WG the morphological blood-nerve barrier is definitive. The meningeal primordium can be first noted as a layer of agglomerated fibroblasts, later toward 13 WG splitting in pachymeninx and leptomeninges and leaving space for intrinsic blood vessels.

Human Malformed Perinatal Anthropological Crania Contribute to New Insight in the Extension of Bone Malformations in Cranial Development.

INTRODUCTION: We describe five abnormal crania which may provide more diagnostic data for assessment of abnormal crania in newborns. METHODS: Five malformed perinatal crania from the Saxtorphian Collection are described using published prenatal abnormal cranial development criteria. These malformations were compared to normal cranial development arising from the migration of neural crest cells. Visual and photographic investigations were performed. RESULTS: The malformed crania were occipital encephalocele, holoprosencephaly, anencephaly, and two without a recognizable diagnosis. The anthropological crania were malformed in the same regions as formerly observed in fetal pathology. These regions were comparable to fields formed during normal cell migration from the neural crest. This has seemingly not previously been demonstrated. One undiagnosed cranium may represent a Treacher Collins syndrome (Case 3). The other undiagnosed cranium (Case 4) could be from a scaphocephalic specimen. DISCUSSION: Sharp borderlines between malformed and non-malformed regions in cranial syndromes may enable improvement in diagnostics.

Discovery of an Anteriorly Deviated, Partially Ossified Xiphoid Process With a Large, Teardrop-Shaped Foramen in a Male Cadaver.

The sternum, or "breastbone," is a principal bony component of the anterior thoracic wall and comprises the manubrium of the sternum, the body of the sternum, and the xiphoid process. The xiphoid process is the most inferior of these elements and commonly presents as a small, solid bone shaped like an inverted triangle. However, clinical literature has reported numerous variations in its size, shape, and presentation, likely the result of its lengthy embryological development from cartilage into fully ossified bone. In this case report, a rare, anteriorly deviated, partially ossified xiphoid process with a large, teardrop-shaped foramen is presented that was discovered during a routine cadaveric dissection of a 75-year-old male within an undergraduate anatomy course. Although anatomical variations in the xiphoid process are often asymptomatic and often only found incidentally through CT or X-ray scans, healthcare professionals should be aware of such variations to avoid both misdiagnoses as well as iatrogenic complications.

Foetal programming in sheep: Reproductive and productive implications.

The aim of this study was to evaluate the effects of pregnant ewe nutrition on the performance of offspring in terms of meat, wool production, and reproduction. Foetal programming in sheep has focused on several aspects related to foetal growth, postnatal production, behaviour, and immunological performance. Currently, significant efforts are being made to understand the endocrine, metabolic, and epigenetic mechanisms involved in offspring development. Current studies have not only evaluated the foetal period, despite the pre-conception parental nutrition has demonstrated an effect on the foetal, embryonic, and pre-implantation periods and can generate permanent effects in the foetal and postnatal phases. The performance of offspring is the result of interactions between the genome, epigenome, and environmental interventions during conception. Several factors influence the expression of phenotypic characteristics in progenies; however, this study focused on presenting data on the effect of pregnant ewe nutrition alone on foetal growth and the productive aspects of their offspring.

Duplicate Radial Artery Variation: A Comprehensive Analysis With Case Report, Literature Review, Embryological Insights and Clinical Significance.

Thorough knowledge of the anatomical variations of the arterial pattern of the upper limb is of high clinical importance in many medical fields, from surgery to nursery and anesthesiologic practice. During a routine dissection at the Anatomy Department of the Medical University of Plovdiv, a rare variation of the vascular system in the upper limb of a study cadaver was observed. The exhibited variation was the occurrence of a brachioradial artery (BRA) that ran along the main axis of the arm, superficially to the median nerve. After dissection of the cubital fossa, an unusually underdeveloped radial artery was also spotted. Per our knowledge, such a type of duplicate radial artery, the coexistence of a BRA and an underdeveloped radial artery has not been reported in the relevant literature on the topic. The underdeveloped radial artery gave a major branch, the recurrent radial artery, a branch usually given by the brachial artery or the BRA in case of a BRA variation. Variations in the arterial pattern could potentially give insight into the features of the embryological development of the vascular system.

Single-cell transcriptional landscapes of bovine peri-implantation development.

Supporting healthy pregnancy outcomes requires a comprehensive understanding of the molecular and cellular programs of peri-implantation development, when most pregnancy failure occurs. Here, we present single-cell transcriptomes of bovine peri-implantation embryo development at day 12, 14, 16, and 18 post-fertilization. We defined the cellular composition and gene expression of embryonic disc, hypoblast, and trophoblast lineages in bovine peri-implantation embryos, and identified markers and pathway signaling that represent distinct stages of bovine peri-implantation lineages; the expression of selected markers was validated in peri-implantation embryos. Using detailed time-course transcriptomic analyses, we revealed a previously unrecognized primitive trophoblast cell lineage. We also characterized conserved and divergence peri-implantation lineage programs between bovine and other mammalian species. Finally, we established cell-cell communication signaling underlies embryonic and extraembryonic cell interaction to ensure proper early development. These data provide foundational information to discover essential biological signaling underpinning bovine peri-implantation development.

CT and MR Appearance of Teeth: Analysis of Anatomy and Embryology and Implications for Disease.

Abnormalities of dental development and anatomy may suggest the presence of congenital or acquired anomalies. The detection of abnormalities, therefore, is an important skill for radiologists to achieve. Knowledge of dental embryology and an understanding of the radiologic appearances of teeth at various stages of maturation are required for the appreciation of abnormal dental development. While many tooth abnormalities are well-depicted on dedicated dental radiographs, the first encounter with a dental anomaly may be by a radiologist on a computed tomographic (CT) or magnetic resonance (MR) exam performed for other reasons. This article depicts normal dental anatomy and development, describing the appearance of the neonatal dentition on CT and MRI, the modalities most often encountered by clinical radiologists. The radiology and dental literature are reviewed, and key concepts are illustrated with supplemental cases from our institution. The value of knowledge of dental development is investigated using the analysis of consecutive MR brain examinations. Finally, the anatomical principles are applied to the diagnosis of odontogenic infection on CT. Through analysis of the literature and case data, the contrast of dental pathology with normal anatomy and development facilitates the detection and characterization of both congenital and acquired dental disease.

Flipped online teaching of histology and embryology with design thinking: design, practice and reflection.

BACKGROUND: Flexible hybrid teaching has become the new normal of basic medical education in the postepidemic era. Identifying ways to improve the quality of curriculum teaching and achieve high-level talent training is a complex problem that urgently needs to be solved. Over the course of the past several semesters, the research team has integrated design thinking (DT) into undergraduate teaching to identify, redesign and solve complex problems in achieving curriculum teaching and professional talent training objectives. METHODS: This study is an observational research. A total of 156 undergraduate stomatology students from Jining Medical University in 2021 were selected to participate in two rounds of online flipped teaching using the design thinking EDIPT (empathy, definition, idea, prototype, and test) method. This approach was applied specifically to the chapters on the respiratory system and female reproductive system. Data collection included student questionnaires, teacher-student interviews, and exam scores. GraphPad Prism software was used for data analysis, and the statistical method was conducted by multiple or unpaired t test. RESULTS: According to the questionnaire results, the flipped classroom teaching design developed using design thinking methods received strong support from the majority of students, with nearly 80% of students providing feedback that they developed multiple abilities during the study process. The interview results indicated that teachers generally believed that using design thinking methods to understand students' real needs, define teaching problems, and devise instructional design solutions, along with testing and promptly adjusting the effectiveness through teaching practices, played a highly positive role in improving teaching and student learning outcomes. A comparison of exam scores showed a significant improvement in the exam scores of the class of 2021 stomatology students in the flipped teaching chapters compared to the class of 2020 stomatology students, and this difference was statistically significant. However, due to the limitation of the experimental chapter scope, there was no significant difference in the overall course grades. CONCLUSION: The study explores the application of design thinking in histology and embryology teaching, revealing its positive impact on innovative teaching strategies and students' learning experience in medical education. Online flipped teaching, developed through design thinking, proves to be an effective and flexible method that enhances student engagement and fosters autonomous learning abilities.

External Disruption of Ocular Development in Utero.

The intricate steps of human ocular embryology are impacted by cellular and genetic signaling pathways and a myriad of external elements that can affect pregnancy, such as environmental, metabolic, hormonal factors, medications, and intrauterine infections. This review focuses on presenting some of these factors to recognize the multifactorial nature of ocular development and highlight their clinical significance. This review is based on English-language articles sourced from PubMed, Web of Science, and Google Scholar; keywords searched included "ocular development in pregnancy," "ocular embryology," "maternal nutrition," "ophthalmic change," and "visual system development." While some animal models show the disruption of ocular embryology from these external factors, there are limited post-birth assessments in human studies. Much remains unknown about the precise mechanisms of how these external factors can disrupt normal ocular development in utero, and more significant research is needed to understand the pathophysiology of these disruptive effects further. Findings in this review emphasize the importance of additional research in understanding the dynamic association between factors impacting gestation and neonatal ocular development, particularly in the setting of limited resources.

Gastroschisis: embriology, pathogenesis, risk factors, prognosis, and ultrasonographic markers for adverse neonatal outcomes.

Gastroschisis is the most common congenital defect of the abdominal wall, typically located to the right of the umbilical cord, through which the intestinal loops and viscera exit without being covered by the amniotic membrane. Despite the known risk factors for gastroschisis, there is no consensus on the cause of this malformation. Prenatal ultrasound is useful for diagnosis, prognostic prediction (ultrasonographic markers) and appropriate monitoring of fetal vitality. Survival rate of children with gastroschisis is more than 95% in developed countries; however, complex gastroschisis requires multiple neonatal interventions and is associated with adverse perinatal outcomes. In this article, we conducted a narrative review including embryology, pathogenesis, risk factors, and ultrasonographic markers for adverse neonatal outcomes in fetuses with gastroschisis. Prenatal risk stratification of gastroschisis helps to better counsel parents, predict complications, and prepare the multidisciplinary team to intervene appropriately and improve postnatal outcomes.