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Embryology
Kinds of Embryology Selected AbstractsDual Origin Extracranial Vertebral Artery: Case Report and EmbryologyJOURNAL OF NEUROIMAGING, Issue 2 2008Ajith J. Thomas MD ABSTRACT Duplication of the vertebral artery origin is a rare vascular anomaly. The authors describe this finding in a patient who underwent neurointerventional treatment for a midbasilar aneurysm. The embryology and clinical significance is also presented. [source] Book review: From Embryology to Evo-Devo: A History of Developmental EvolutionAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 2 2008Neil W. Blackstone No abstract is available for this article. [source] OTTO ZIETZSCHMANN PRIZE for the Promotion of Research in Veterinary Embryology , donated by Zietzschmann's Pupil Fritz Preuß,ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2008Article first published online: 10 MAR 200 No abstract is available for this article. [source] Enhancing bioethics, enhancing bioscience: Bioethics and the New Embryology: Springboards for Debate by Scott F. Gilbert, Anna L. Tyler, and Emily J. Zackin. (2005).BIOESSAYS, Issue 10 2006Sunderland MA: Sinauer Associates. No abstract is available for this article. [source] Boris Balinsky: transition from embryology to developmental biologyBIOESSAYS, Issue 9 2005Vladimir Korzh This is the story of a textbook that students of developmental biology have used for 45 years. "An Introduction to Embryology" was released soon after a role for genes in the control of development became finally recognized but not yet well documented. Thus this book manifested the transition from embryology to developmental biology. The story of its author, Boris Balinsky, who against all odds survived to write this book, is remarkable on its own. He started his scientific career in the USSR, but due to 20th century social and political upheavals, ended it in South Africa. This article will shed light on the life of Boris Balinsky, a scientist and writer and will explore the origins of his book. BioEssays 27:970,977, 2005. © 2005 Wiley Periodicals, Inc. [source] Embryology of Hortonioideae and Monimioideae (Monimiaceae, Laurales): characteristics of the ,lower' monimioidsBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2008YUKITOSHI KIMOTO We investigated the embryology of the ,lower' monimioids, i.e. Monimioideae (Monimia, Palmeria and Peumus) and Hortonioideae (Hortonia), which are poorly described embryologically. Our results show that, contrary to what has been reported in the literature, ,lower' monimioids show very little variation in their embryological characters. Comparisons with Mollinedioideae (a large derived subfamily in Monimiaceae) and other families in Laurales show that the ,lower' monimioids are relatively consistent in sharing predominantly isobilateral tetrads of microspores and megaspores, a non-specialized chalaza, and a mesotestal,endotestal seed coat (with tracheoidal cells of the meso- and endotesta). It is likely that, while the shared successive cytokinesis during meiosis of microspore mother cells supports the Monimiaceae,Hernandiaceae,Lauraceae clade obtained by molecular evidence, no synapomorphies exist to support a sister-group relationship of Monimiaceae with Hernandiaceae or Lauraceae. Instead, the lack of hypostase in ovules and/or young seeds, the lack of endosperm in mature seeds and the amoeboid tapetum in the anther are likely synapomorphies of Hernandiaceae and Lauraceae. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 228,241. [source] Traditions and peculiarities of clinical anatomy education in RussiaCLINICAL ANATOMY, Issue 2 2002Ilia I. Kagan Abstract The Russian experience in clinical anatomy education is described in this article. Such training is provided by the Department of Operative Surgery and Topographical Anatomy both during the pregraduate (undergraduate) period for medical students and in the postgraduate period for interns, residents, physicians, and surgeons of different specialties. The teaching of clinical anatomy in the pregraduate period occurs in combination with the study of operative surgery and follows the study of gross anatomy in the Department of Human Anatomy and microscopic anatomy in the Department of Histology, Cytology and Embryology. Clin. Anat. 15:152,156, 2002. © 2002 Wiley-Liss, Inc. [source] The cause and prevention of human birth defects: What have we learned in the past 50 years?CONGENITAL ANOMALIES, Issue 1 2001Robert L. Brent ABSTRACT This review article dealig with the subject of "The Cause and Prevention of Human Birth Defects" was prepared in celebration of the 40th anniversary of the Japanese Teratology Society. It begins with recollections of some of the important contributions of Japanese scientists in the fields of teratology and embryology and a summary of the many scientific and medical accomplishments of the past 50 years in the fields of teratology, genetics, developmental biology, epidemiology and genetics. The review includes a summary of the drugs, chemicals and physical agents that have been documented to result in congenital malformations and reproductive effects when pregnant women are exposed during pregnancy. The principles of teratology were also summarized and emphasize that 1) no teratogenic agent can be described qualitatively as a teratogen, since a teratogenic exposure must include not only the agent, but also the dose and the time in pregnancy when the exposure occurs. 2) Even agents that have been demonstrated to result in malformatins cannot produce every type of malformation. 3) Known teratogens can be presumptively identified by the spectrum of malformations they produce. 4) It is easier to exclude an agent as a cause of birth defects than to definitively conclude that it was responsible for birth defects. 5) When evaluating the risk of exposures, the dose is a crucial component in determining the risk. 6) Teratogenic agents follow a toxicological dose response curve. This means that each teratogen has a threshold dose, below which, there is no risk of teratogenensis, no matter when in pregnancy the exposure occurred. 7) The evaluation of a child with congenital malformations connot be adequately performed unless it is approached with the same scholarship and detail, as is any other complicated medical problem. 8) Each physician must recognize the consequences of providing erroneous reproductive risks to pregnant women exposed to drugs and chemicals during pregnancy or alleging that a child's malformations are due to an environmental agent without performing a complete and scholarly evaluation. [source] Gene transfer into chicken embryos as an effective system of analysis in developmental biologyDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 3 2000Sadao Yasugi Chicken embryos have been used as a model animal in developmental biology since the time of comparative and experimental embryology. Recent application of gene transfer techniques to the chicken embryo increases their value as an experimental animal. Today, gene transfer into chicken cells is performed by three major systems, lipofection, electroporation and the virus-mediated method. Each system has its own features and applicability. In this overview and the associated four minireviews, the methods and application of each system will be presented. [source] Graphic and movie illustrations of human prenatal development and their application to embryological education based on the human embryo specimens in the Kyoto collectionDEVELOPMENTAL DYNAMICS, Issue 2 2006Shigehito Yamada Abstract Morphogenesis in the developing embryo takes place in three dimensions, and in addition, the dimension of time is another important factor in development. Therefore, the presentation of sequential morphological changes occurring in the embryo (4D visualization) is essential for understanding the complex morphogenetic events and the underlying mechanisms. Until recently, 3D visualization of embryonic structures was possible only by reconstruction from serial histological sections, which was tedious and time-consuming. During the past two decades, 3D imaging techniques have made significant advances thanks to the progress in imaging and computer technologies, computer graphics, and other related techniques. Such novel tools have enabled precise visualization of the 3D topology of embryonic structures and to demonstrate spatiotemporal 4D sequences of organogenesis. Here, we describe a project in which staged human embryos are imaged by the magnetic resonance (MR) microscope, and 3D images of embryos and their organs at each developmental stage were reconstructed based on the MR data, with the aid of computer graphics techniques. On the basis of the 3D models of staged human embryos, we constructed a data set of 3D images of human embryos and made movies to illustrate the sequential process of human morphogenesis. Furthermore, a computer-based self-learning program of human embryology is being developed for educational purposes, using the photographs, histological sections, MR images, and 3D models of staged human embryos. Developmental Dynamics 235:468,477, 2006. © 2005 Wiley-Liss, Inc. [source] Rethinking axial patterning in amphibiansDEVELOPMENTAL DYNAMICS, Issue 4 2002Mary Constance Lane Abstract Recent revisions in the Xenopus laevis fate map led to the designation of the rostral/caudal axis and reassignment of the dorsal/ventral axis (Lane and Smith [1999] Development 126:423,434; Lane and Sheets [2000] Dev. Biol. 225:37,58). It is unprecedented to reassign primary embryonic axes after many years of research in a model system. In this review, we use insights about vertebrate development from anatomy and comparative embryology, as well as knowledge about gastrulation in frogs, to reexamine several traditional amphibian fate maps. We show that four extant maps contain information on the missing rostral/caudal axis. These maps support the revised map as well as the designation of the rostral/caudal axis and reassignment of the dorsal/ventral axes. To illustrate why it is important for researchers to use the revised map and nomenclature when thinking about frog and fish embryos, we present an example of alternative interpretations of "dorsalized" zebrafish mutations. © 2002 Wiley-Liss, Inc. [source] Integration and differentiation of human embryonic stem cells transplanted to the chick embryoDEVELOPMENTAL DYNAMICS, Issue 1 2002Ronald S. Goldstein Abstract Human embryonic stem (ES) cells are pluripotent cells that can differentiate into a large array of cell types and, thus, hold promise for advancing our understanding of human embryology and for contributing to transplantation medicine. In this study, differentiation of human ES cells was examined in vivo by in ovo transplantation to organogenesis-stage embryos. Colonies of human ES cells were grafted into or in place of epithelial-stage somites of chick embryos of 1.5 to 2 days of development. The grafted human ES cells survived in the chick host and were identified by vital staining with carboxyfluorescein diacetate or use of a green fluorescent protein,expressing cells. Histologic analysis showed that human ES cells are easily distinguished from host cells by their larger, more intensely staining nuclei. Some grafted cells differentiated en masse into epithelia, whereas others migrated and mingled with host tissues, including the dorsal root ganglion. Colonies grafted directly adjacent to the host neural tube produced primarily structures with the morphology and molecular characteristics of neural rosettes. These structures contain differentiated neurons as shown by ,-3-tubulin and neurofilament expression in axons and cell bodies. Axons derived from the grafted cells penetrate the host nervous system, and host axons enter the structures derived from the graft. Our results show that human ES cells transplanted in ovo survive, divide, differentiate, and integrate with host tissues and that the host embryonic environment may modulate their differentiation. The chick embryo, therefore, may serve as an accessible and unique experimental system for the study of in vivo development of human ES cells. © 2002 Wiley-Liss, Inc. [source] The dynamics of development and evolution: Insights from behavioral embryologyDEVELOPMENTAL PSYCHOBIOLOGY, Issue 8 2007Robert Lickliter Abstract The perspective that features of species-typical behavior could be traced to experience that occurred prenatally was raised by Zing-Yang Kuo [1921 Journal of Philosophy 18: 645,664] early in the last century and Gilbert Gottlieb subsequently elaborated on and provided empirical support for this idea over the course of more than four decades of innovative psychobiological research. Although we are still a long way from fully understanding the specific pathways and processes by which prenatal experience can influence postnatal development, Gottlieb's research with precocial birds provided significant insights into the conditions and experiences of prenatal development involved in the achievement of species-typical perception and behavior. In particular, his elegant series of studies on the development of species identification in ducklings documented how the features and patterns of recurring prenatal sensory experience (including self-stimulation) guide and constrain the young individual's selective attention, perception, learning, and memory during both prenatal and postnatal periods. I review how this body of research supports the view that the structure and functions of the developing organism and its developmental ecology together form a relationship of mutual influence on the emergence, maintenance, and transformation of species-typical behavior. I also explore how Gottlieb's empirical demonstrations of the prenatal roots of so-called "instinctive" behavior provided a foundation for his conceptual efforts to define the links between developmental and evolutionary change. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 749,757, 2007. [source] Phylogenetic analysis of developmental and postnatal mouse cell lineagesEVOLUTION AND DEVELOPMENT, Issue 1 2010Stephen J. Salipante SUMMARY Fate maps depict how cells relate together through past lineage relationships, and are useful tools for studying developmental and somatic processes. However, with existing technologies, it has not been possible to generate detailed fate maps of complex organisms such as the mouse. We and others have therefore proposed a novel approach, "phylogenetic fate mapping," where patterns of somatic mutation carried by the individual cells of an animal are used to retrospectively deduce lineage relationships through phylogenetic inference. Here, we have cataloged genomic polymorphisms at 324 mutation-prone polyguanine tracts for nearly 300 cells isolated from a single mouse, and have explored the cells' lineage relationships both phylogenetically and through a network-based approach. We present a model of mouse embryogenesis, where an early period of substantial cell mixing is followed by more coherent growth of clones later. We find that cells from certain tissues have greater numbers of close relatives in other specific tissues than expected from chance, suggesting that those populations arise from a similar pool of ancestral lineages. Finally, we have investigated the dynamics of cell turnover (the frequency of cell loss and replacement) in postnatal tissues. This work offers a longitudinal study of developmental lineages, from conception to adulthood, and provides insight into basic questions of mouse embryology as well as the somatic processes that occur after birth. [source] Mitogenomics and phylogenomics reveal priapulid worms as extant models of the ancestral EcdysozoanEVOLUTION AND DEVELOPMENT, Issue 6 2006Bonnie L. Webster SUMMARY Research into arthropod evolution is hampered by the derived nature and rapid evolution of the best-studied out-group: the nematodes. We consider priapulids as an alternative out-group. Priapulids are a small phylum of bottom-dwelling marine worms; their tubular body with spiny proboscis or introvert has changed little over 520 million years and recognizable priapulids are common among exceptionally preserved Cambrian fossils. Using the complete mitochondrial genome and 42 nuclear genes from Priapulus caudatus, we show that priapulids are slowly evolving ecdysozoans; almost all these priapulid genes have evolved more slowly than nematode orthologs and the priapulid mitochondrial gene order may be unchanged since the Cambrian. Considering their primitive bodyplan and embryology and the great conservation of both nuclear and mitochondrial genomes, priapulids may deserve the popular epithet of "living fossil." Their study is likely to yield significant new insights into the early evolution of the Ecdysozoa and the origins of the arthropods and their kin as well as aiding inference of the morphology of ancestral Ecdysozoa and Bilateria and their genomes. [source] The evolution of gnathostome development: Insight from chondrichthyan embryologyGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 12 2009J. Andrew Gillis Alcian blue skeletal preparations of wild-type (front) and retinoic acid-treated (back) embryos of the little skate, Leucoraja erinacea. As in paired fins, the cartilaginous gill rays of L. erinacea are patterned by a retinoic acid-regulated Sonic hedghog (Shh)-Fibroblast growth factor 8 (Fgf8) feedback loop, and exposure to exogenous retinoic acid induces ectopic Shh expression and mirror-image gill ray duplications. (Cover design by Kalliopi Monoyios and Randy Dahn). See the review by Gillis and Shubin in this issue. [source] New school in liver development: Lessons from zebrafish,HEPATOLOGY, Issue 5 2009Jaime Chu There is significant overlap in the genes and pathways that control liver development and those that regulate liver regeneration, hepatic progenitor cell expansion, response to injury, and cancer. Additionally, defects in liver development may underlie some congenital and perinatal liver diseases. Thus, studying hepatogenesis is important for understanding not only how the liver forms, but also how it functions. Elegant work in mice has uncovered a host of transcription factors and signaling molecules that govern the early steps of hepatic specification; however, the inherent difficulty of studying embryogenesis in utero has driven developmental biologists to seek new systems. The rapidly developing vertebrate zebrafish is a favorite model for embryology. The power of forward genetic screens combined with live real-time imaging of development in transparent zebrafish embryos has highlighted conserved processes essential for hepatogenesis and has uncovered some exciting new players. This review presents the advantages of zebrafish for studying liver development, underscoring how studies in zebrafish and mice complement each other. In addition to their value for studying development, zebrafish models of hepatic and biliary diseases are expanding, and using these small, inexpensive embryos for drug screening has become de rigueur. Zebrafish provide a shared platform for developmental biology and translational research, offering innovative methods for studying liver development and disease. The story of hepatogenesis has something for everyone. It involves transcriptional regulation, cell-cell interaction, signaling pathways, control of cell proliferation and apoptosis, plus morphogenic processes that sculpt vasculature, parenchymal cells, and mesenchyme to form the multifaceted liver. Decades of research on liver development in mice and other vertebrates offer valuable lessons in how the multipotent endoderm is programmed to form a functional liver. Of equal importance are insights that have illuminated the mechanisms by which hepatic progenitors are activated in a damaged liver, how the adult liver regenerates, and, possibly, the basis for engineering liver cells in vitro for cell transplantation to sustain patients with liver failure. Moreover, processes that are key to liver development are often co-opted during pathogenesis. Therefore, reviewing hepatogenesis is informative for both basic and translational researchers. In this review, we bring to light the many advantages offered by the tropical freshwater vertebrate zebrafish (Danio rerio) in studying hepatogenesis. By comparing zebrafish and mice, we highlight how work in each system complements the other and emphasize novel paradigms that have been uncovered using zebrafish. Finally, we highlight exciting efforts using zebrafish to model hepatobiliary diseases. (HEPATOLOGY 2009.) [source] The amazing universe of hepatic microstructure,HEPATOLOGY, Issue 2 2009Valeer J. Desmet An informal review is presented by the author of his 50 years of involvement in practice and research in hepatopathology. Some background for the author's attitude and meandering pathway into his professional career serves as introduction to a short discussion of the main topics of his interest and expertise. Histogenesis of liver cancer was the theme of early work for a Ph.D. thesis, the results of which were lost into oblivion due to local rules and circumstances, but were rescued three decades later. His conclusions about the cells of origin of liver cancer remain concordant with the newer concepts in the field after nearly half a century. Studies in the field of chronic hepatitis became a long saga, involving the first classification of this syndrome by "the Gnomes" in 1968, histochemical investigations of viral antigens, lymphocyte subsets and adhesion molecules, and a quarter century later, the creation of a new classification presently in use. Cholestasis was a broadening field in diagnostic entities and involved the study of liver lesions, comprising pathways of bile regurgitation (including reversed secretory polarity of hepatocytes) and so-called ductular reaction. The latter topic has a high importance for the various roles it plays in modulating liver tissue of chronic cholestasis into biliary cirrhosis, and as the territory of hepatic progenitor cells, crucial for liver regeneration in adverse conditions and in development of liver cancer. Study of the embryology of intrahepatic bile ducts helped to clarify the strange appearance of the ducts in "ductal plate configuration" in several conditions, including some forms of biliary atresia with poor prognosis and all varieties of fibrocystic bile duct diseases with "ductal plate malformation" as the basic morphologic lesion. (HEPATOLOGY 2009;50:333,344.) [source] Comparison of developmental trajectories in the starlet sea anemone Nematostella vectensis: embryogenesis, regeneration, and two forms of asexual fissionINVERTEBRATE BIOLOGY, Issue 2 2007Adam M. Reitzel Abstract. The starlet sea anemone, Nematostella vectensis, is a small burrowing estuarine animal, native to the Atlantic coast of North America. In recent years, this anemone has emerged as a model system in cnidarian developmental biology. Molecular studies of embryology and larval development in N. vectensis have provided important insights into the evolution of key metazoan traits. However, the adult body plan of N. vectensis may arise via four distinct developmental trajectories: (1) embryogenesis following sexual reproduction, (2) asexual reproduction via physal pinching, (3) asexual reproduction via polarity reversal, and (4) regeneration following bisection through the body column. Here, we compare the ontogenetic sequences underlying alternate developmental trajectories. Additionally, we describe the predictable generation of anomalous phenotypes that can occur following localized injuries to the body column. These studies suggest testable hypotheses on the molecular mechanisms underlying alternate developmental trajectories, and they provoke new questions about the evolution of novel developmental trajectories and their initiation via environmental cues. [source] Evolution of the vertebrate jaw: comparative embryology and molecular developmental biology reveal the factors behind evolutionary noveltyJOURNAL OF ANATOMY, Issue 5 2004Shigeru Kuratani Abstract It is generally believed that the jaw arose through the simple transformation of an ancestral rostral gill arch. The gnathostome jaw differentiates from Hox -free crest cells in the mandibular arch, and this is also apparent in the lamprey. The basic Hox code, including the Hox -free default state in the mandibular arch, may have been present in the common ancestor, and jaw patterning appears to have been secondarily constructed in the gnathostomes. The distribution of the cephalic neural crest cells is similar in the early pharyngula of gnathostomes and lampreys, but different cell subsets form the oral apparatus in each group through epithelial,mesenchymal interactions: and this heterotopy is likely to have been an important evolutionary change that permitted jaw differentiation. This theory implies that the premandibular crest cells differentiate into the upper lip, or the dorsal subdivision of the oral apparatus in the lamprey, whereas the equivalent cell population forms the trabecula of the skull base in gnathostomes. Because the gnathostome oral apparatus is derived exclusively from the mandibular arch, the concepts ,oral' and ,mandibular' must be dissociated. The ,lamprey trabecula' develops from mandibular mesoderm, and is not homologous with the gnathostome trabecula, which develops from premandibular crest cells. Thus the jaw evolved as an evolutionary novelty through tissue rearrangements and topographical changes in tissue interactions. [source] Charles Darwin, embryology, evolution and skeletal plasticityJOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2010B. K. Hall Summary Darwin provided us with the theory of evolutionary change through natural selection. Just as important to the science of biology was Darwin's recognition that all organisms could be classified and were related to one another because they arose from a single common universal ancestor , what we know as the universal tree of life (UtoL). All the features of the skeletal biology of fish therefore can be explained, both in an evolutionary framework (ultimate causation) and in the framework of development, growth and physiology (proximate causation). Neither approach is complete without the other. I will outline the elements of Darwin's theories on evolution and classification and, as importantly, discuss what was missing from Darwin's theories. An important class of evidence for evolution used by Darwin came from embryology, both comparative embryology and the existence of vestiges and atavisms. After discussing this evidence I examine some fundamental features of skeletal development and evolution These include: the presence of four skeletal systems in all vertebrates; the existence of two skeletons, one based on cartilage, the other on bone and dentine; the modular nature of skeletal development and evolution; and the plasticity of the skeleton in response to either genetic or environmental changes. [source] The molecular metamorphosis of embryology: implications for medical educationMEDICAL EDUCATION, Issue 5 2004Isaura Tavares No abstract is available for this article. [source] Normal and abnormal fetal cardiac anatomyPRENATAL DIAGNOSIS, Issue 13 2004Andrew C. Cook Abstract The heart is often perceived as a difficult organ to understand by ultrasound during fetal life. This is undoubtedly reflected in the low detection rate of cardiac abnormalities as compared to those of most other organ systems in the fetus. In this article we start by updating classical concepts of cardiac embryology, many of which were previously difficult to understand since they were overly simplistic or purely observational. We then lead on to the structure and growth of the fully formed fetal heart where we review the anatomy and ultrasound appearances in detail and provide comparisons with major abnormalities. We emphasise the fact that a solid understanding of cardiac anatomy can enable those involved in fetal medicine to make full use of the views of the heart that are obtained by ultrasound and which are often only transient. Copyright © 2004 John Wiley & Sons, Ltd. [source] Normal and abnormal development of the urogenital tractPRENATAL DIAGNOSIS, Issue 11 2001Peter M. Cuckow Abstract An understanding of the normal development of the urogenital tract, at both the structural and molecular level, gives an insight into the mechanisms involved in renal pathology. In this review we will outline embryology of normal and abnormal renal development and discuss the function of some of the key regulatory molecules which have been described recently. Copyright © 2001 John Wiley & Sons, Ltd. [source] Embryonic Staging System for the Black Mastiff Bat, Molossus rufus (Molossidae), Correlated With Structure-Function Relationships in the AdultTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 2 2009Mark J. Nolte The helmeted appearance of the black mastiff bat, Molossus rufus, at embryonic stage 21 results from the anterior margins of the ears being progressively situated near the facial midline during development. Comparative bat embryology provides a foundation for understanding unique mammalian and chiropteran (bat) adaptations, such as the marked ability of M. rufus to use its compactly folded wings during terrestrial quadrupedal locomotion. See Nolte et al., on page 155, in this issue. [source] Cervical thymic anomalies,The Texas Children's Hospital experienceTHE LARYNGOSCOPE, Issue 10 2009Angela K. Sturm-O'Brien MD Abstract Objectives/Hypothesis: To review the presentation and management of cervical thymic cysts and ectopic thymic tissue at Texas Children's Hospital over the last 25 years. Study Design: Case report and case series using retrospective chart review. Methods: A case report is presented of a recently diagnosed thymic cyst highlighting diagnostic, management, and treatment strategies available for optimizing management of patients with significant mediastinal extension. We then present a retrospective review of cervical thymic anomalies at a tertiary academic medical center over a 25-year span (1983,present). Data extracted include patients' characteristics, clinical presentation, diagnostic workup, surgical management, and postoperative complications. Results: Fifteen patients were found to have a pathological diagnosis of cervical thymic cyst, and 10 patients had a diagnosis of ectopic thymic tissue in the neck. This is the largest case series of cervical thymic anomalies presented in the literature to date. Patients' characteristics, diagnostic techniques, and treatment strategies are discussed. Conclusions: Cervical thymic anomalies are a rare but necessary part of the differential diagnosis of a cervical mass. Computed tomography scan can both narrow the preoperative differential diagnosis and aid in surgical planning for thymic cyst excision. A full discussion of the embryology, clinical presentation, and management of cervical thymic cysts and a review of the current literature is presented. Laryngoscope, 2009 [source] Tracheal Agenesis in NewbornsTHE LARYNGOSCOPE, Issue 9 2004Timothy A. Lander MD Abstract Objectives/Hypothesis: A series of three newborns with tracheal agenesis is described. The preferred methods of diagnosis, description of the clinical course, and a review of the pertinent embryology, associated anomalies, and clinical management are presented. Study Design: A retrospective study of a clinical series of referred patients from 2002 to 2003 who were seen at a single institution. Methods: Chart review for clinical course and pathological specimens was performed in all cases. Three patients were identified with tracheal agenesis. Results: All three newborns died within 48 hours of birth. All of the children underwent emergency laryngoscopy and neck exploration. Gross and microscopic pathological examination was accomplished on all patients. Conclusion: Although tracheal agenesis is rare, it may be more common than previously thought. The diagnosis is not straightforward, and the prognosis is grim. The embryology of the trachea and other foregut derivatives is closely related, and associated birth defects are common. [source] Factors in the Pathogenesis of Tumors of the Sphenoid and Maxillary Sinuses: A Comparative Study,THE LARYNGOSCOPE, Issue S96 2000Anthony J. Reino MD Abstract Objectives/Hypothesis To explain the processes that lead to the development of tumors in the maxillary and sphenoid sinuses. Study Design A 32-year review of the world's literature on neoplasms of these two sinuses and a randomized case-controlled study comparing the normal mucosal architecture of the maxillary to the sphenoid sinus. Methods Analysis of a 32-year world literature review reporting series of cases of maxillary and sphenoid sinus tumors. Tumors were classified by histological type and separated into subgroups if an individual incidence rate was reported. Histomorphometry of normal maxillary and sphenoid sinus mucosa was performed in 14 randomly selected patients (10 sphenoid and 4 maxillary specimens). Specimens were fixed in 10% formalin, embedded in paraffin, and stained with periodic acid,Schiff (PAS) and hematoxylin. Histomorphometric analysis was performed with a Zeiss Axioscope light microscope (Carl Zeiss Inc., Thornwood, NY) mounted with a Hamamatsu (Hamamatsu Photonics, Tokyo, Japan) color-chilled 3 charge coupled device digital camera. The images were captured on a 17-inch Sony (Sony Corp., Tokyo, Japan) multiscan monitor and analyzed with a Samba 4000 Image Analysis Program (Samba Corp., Los Angeles, CA). Five random areas were selected from strips of epithelium removed from each sinus, and goblet and basal cell measurements were made at magnifications ×100 and ×400. Results The literature review revealed that the number and variety of tumors in the maxillary sinus are much greater than those in the sphenoid. The incidence of metastatic lesions to each sinus is approximately equal. No recognized pattern of spread from any particular organ system could be determined. On histomorphometric study there were no statistically significant differences between the sinuses in the concentration of goblet cells, basal cells, or seromucinous glands. Conclusions Factors involved in the pathogenesis of tumors of the maxillary and sphenoid sinuses include differences in nasal physiology, embryology, morphology, and topography. There are no significant histological differences in the epithelium and submucous glands between the two sinuses to explain the dissimilar formation of neoplasms. [source] New Insights in Vascular Development: Vasculogenesis and Endothelial Progenitor CellsANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2009S. Käßmeyer Summary In the course of new blood vessel formation, two different processes , vasculogenesis and angiogenesis , have to be distinguished. The term vasculogenesis describes the de novo emergence of a vascular network by endothelial progenitors, whereas angiogenesis corresponds to the generation of vessels by sprouting from pre-existing capillaries. Until recently, it was thought that vasculogenesis is restricted to the prenatal period. During the last decade, one of the most fascinating innovations in the field of vascular biology was the discovery of endothelial progenitor cells and vasculogenesis in the adult. This review aims at introducing the concept of adult vasculogenesis and discusses the efforts to identify and characterize adult endothelial progenitors. The different sources of adult endothelial progenitors like haematopoietic stem cells, myeloid cells, multipotent progenitors of the bone marrow, side population cells and tissue-residing pluripotent stem cells are considered. Moreover, a survey of cellular and molecular control mechanisms of vasculogenesis is presented. Recent advances in research on endothelial progenitors exert a strong impact on many different disciplines and provide the knowledge for functional concepts in basic fields like anatomy, histology as well as embryology. [source] Bilateral intravesical ureterocele associated with unilateral partial duplication of the ureter and other anomalies: proposal of a new variant to the classification of ureterocles based on a perinatal autopsy, review of the literature and embryologyAPMIS, Issue 10 2010SUNIL JAIMAN Jaiman S, Ulhøj BP. Bilateral intravesical ureterocele associated with unilateral partial duplication of the ureter and other anomalies: proposal of a new variant to the classification of ureterocles based on a perinatal autopsy, review of the literature and embryology. APMIS 2010; 118: 809,14. The aims of this study were to demonstrate a case of bilateral intravesical ureterocele associated with megacystis and mega-ureters, unilateral partial duplication of the ureter and unilateral segmental renal dysplasia of the upper pole and an accessory spleen and to propose an addition of the new variant to the classification of ureteroceles. A perinatal necropsy was conducted on the 21-week fetus by employing the Rokitansky procedure with evisceration performed in blocks. The autopsy revealed the aforementioned abnormalities without cardiac or neural anomalies. The amniocentesis report was normal. Ureterocele is a saccular expansion of the distal ureter. It is most commonly observed in females and children and usually affects the upper moiety of a complete pyeloureteral duplication. Four types of ureteroceles are described: (A) ureterocele with single ureter (10%); (B) ureterocele with total duplication and intravesical development (10%); (C) ureterocele with total duplication and extravesical development (62%); and (D) ureterocele with ectopic ureter (3%). One case in a new born with bilateral intravesical ureterocele associated with hydrouretero-nephrosis and hyperechogenic spots in kidneys has been reported, but bilateral intravesical ureterocele with unilateral incomplete pyeloureteral duplication has never been described in the literature. [source] | |||||||||||||||||||||||||||||||