SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
The publications of fifty years (1925-1974) of the histroy of biology and embryology are surveyed. In America, the earliest background for work during this period was provided by the collectors, mainly physicians, of books into extensive private libraries. The collectors, for instance Osler, Cushing, and Fulton in this country and Geoffrey Keynes abroad, became expert technical bibliographers during the early part of the half-century under consideration. High standards for medical, thus biological history, insofar as these fields overlap, were also set earlier by Sudhoff's Institut für Geschichte der Medizin in Leipzig, and American historical studies benefited when Sigerist came from Leipzig to Baltimore in the early 1930's. Textbooks of medical history are omitted from discussion here, but a number of more or less general histories of biology published within the specified period are briefly evaluated. The discussion next turns to histories of embryology, general and special. Recent monographs on the classical embryologists, Wolff and von Baer, are enumerated, as are a number of biographies and autobiographies of important embryologists published here or abroad during our half-century. Then general histories of embryology are discussed, and finally some specialized ones. Needham, Roger, and Adelmann are singled out as the most important contributors to the history of embryology, in the West, during the period covered. Few of the contributors to the history of biology and medicine during the years of 1925 through 1974 were trained as historians while students. It is concluded that the History of Science Society has performed an important contribution in professionalizing the history of biology and embryology, but it is pointed out that a great new challenge faces it in the necessity to counteract anti-historical and anti-intellectual moods and movements of today.
Various congenital anomalies of branchial origin are found in the neck region. Understanding the varied radiologic appearances of these anomalies is greatly aided by familiarity with their embryologic origins. By considering the anatomic location and radiologic appearance, the precise embryologic origin can be accurately predicted. Defects of the branchial apparatus include branchial, thymic, and parathyroid anomalies, which may manifest as cysts, sinuses, fistulas, and ectopic glands. The embryologic model is used to explain the origins of all branchial apparatus anomalies. The most accepted theory proposes that vestigial remnants result from incomplete obliteration of the branchial apparatus or buried cell rests, and, thus, if cells are trapped in the branchial apparatus during the embryologic stage, they can form branchial cysts later in life. By understanding the embryologic basis for these defects, the radiologist is better able to interpret the findings encountered with the various imaging modalities used in the evaluation of these anomalies.
The Alsatian medieval chronicles report numerous examples of monstrous births; with the development of printing, fly sheets appear in order to relate exceptional phenomena. In 1652, a chair of anatomy was created; embryology and teratology, at that time solely morphological sciences, depended on anatomy. In 1670, the first anatomical theatre was built, and as early as 1672, a meticulous dissection, exceptional at that time, was performed on a thoracodymus double monster born in Strasbourg. In 1919, when the Faculty of Medicine was reorganized after Alsace was restored to France, for the first time in France, a specific chair and an institute of embryology and teratology were created. This is the beginning of the famous experimental embryology. In 1945, a chair of zoology and experimental embryology was created at the Faculty of Sciences. F. Keibel (1861-1929), P. Ancel (1873-1961), P. Vintemberger (1891-1983), J. Benoit (1896-1982), and E. Wolff, were among the famous embryologists who worked in Strasbourg.
The embryology of the genital tract and urinary system is described, and the hypothesis is advanced that the vagina is an organ embryologically derived from the mesonephric or Wolffian ducts in addition to the Müllerian tubercle. This is based on experimental studies and case reports in the literature and our own cases of genital malformations, especially in patients with unilateral renal agenesis and an ipsilateral blind vagina. The importance of the mesonephric ducts as guides or 'inductor' elements for adequate Müllerian development is emphasized. A new embryological classification of female genital malformations is proposed, based on these embryological concepts.
A theoretical basis for the embryology of conjoined twins was formulated from clinical experience with ten cases and extensive review of pertinent embryologic and clinical literature, including over 500 cases. Regarding the age old question of fusion or fission, it is concluded that there is no known embryologic process by which conjoined twins can be formed by fission but firm evidence to support fusion in all cases. Whether the fusion occurs between embryos on one embryonic disc or on two is of no consequence since they are all monovular. Intact ectoderm will not fuse to intact ectoderm, and all seven types of conjoined twins are explained by seven possible sites of union in the early embryo. One new term is proposed: parapagus, from the Greek para, meaning "side," combined with pagus, meaning "fixed"; this is the group formerly called dicephalus or diprosopos. These anterolaterally united parapagus twins must result from two nearly parallel notochords in close proximity; craniopagi and pygopagi from fusion at the cranial and caudal neuropores, respectively; cephalopagi and ischiopagi from union at the pharyngeal and cloacal membranes, respectively; thoracopagi from merging of the cardiac anlage; and omphalopagi from fusion of the umbilicus or of the edges of two embryonic discs in any area not including the above sites. Parasitic twins result from embryonic death of one twin, leaving various portions of the body vascularized by the surviving autosite. The rarity of cases (2) not easily explained by the above theories, and the nearly 6% of twins with two umbilical cords arising from the placenta would seem to support these conclusions. Should one wish to learn the methods of a conjurer, he might vainly watch the latter's customary repertoire, and, so long as everything went smoothly, might never obtain a clue to the mysterious performance, baffled by the precision of the manipulations and the complexity of the apparatus; if, however, a single error were made in any part or if a single deviation from the customary method should force the manipulator along an unaccustomed path, it would give the investigator an opportunity to obtain a part or the whole of the secret.(ABSTRACT TRUNCATED AT 400 WORDS)
It has long been held that embryologic fusion planes influence the spread of skin cancer. Embryologic fusion planes have been implicated in the depth of invasion, horizontal spread, and recurrence of cutaneous carcinoma. However, these structures have never been studied in detail. A review of the surgical literature reveals considerable confusion regarding the exact nature, location, and tumor interactions of these fusion planes. We review the gross and microscopic development of sites of embryologic fusion. We examine histologic sections through fusion sites in normally developed adult and fetal fresh cadaver specimens. Our studies, supported by our review of developmental anatomy, indicate that fusion planes do not persist as identifiable anatomic structures that would influence tumor spread.
The paper analyzes the clinical aspects of medical embryology, emphasizes the topical problems of progenesis, fertilization, cleavage, gastrulation, implantation, and histo-, organo-, and systemogenesis. The current status of the studies into the mother-fetus system is explored. The new organizational patterns of the connection between theory and practice, which enables medical embryology to substantially affect the health care system are also discussed.
The life and work of Prof. MUDr. Zdenek Frankenberger is presented with the main focus on the 16-year period of his activities in Slovakia. His contribution to the history of the Bratislava School of Medicine is great both with regard to his activities both as its founder and excellent teacher of generations of Slovak doctors. He was striving hard to establish the Institute of Histology and Embryology whose first head he became. He participated in the establishment and development also of other institutes of the School of Medicine. An analysis of his remarkable and voluminous scientific work displays the extent of his education, knowledge and interests. His studies covered a broad range of scientific problems in the field of histology, microscopic anatomy, embryology, comparative anatomy and anthropology. Yet he was engaged also in faunal studies and became a reknown expert in entomology. Prof. Frankenberger contributed considerably to the executive work of the Medical School and was its vice-dean and dean.
Under consideration are principle conceptions of G. A. Shmidt on the ecological method in embryology: succession between the compared species, difference in the ecology and organization of adult individuals, distinctions in the course of embryogenesis. Difficulties in a strict observation of all these principles are analyzed in comparative embryological investigations. Possible use of the above principles for studying the intrespecies variability of ontogenetical processes is shown.
The possibility that cartilages of differing embryological origins behave as separate types with respect to cell-to-cell associations was tested by placing the cut ends of transversely sectioned embryonic chick tibial cartilages (of mesodermal origin) in apposition to transversely sectioned Meckel's cartilages (neural crest (ectodermal) cartilage) on the surface of a semi-solid organ culture medium and maintaining the combinations in vitro for five to ten days. Tibia-tibia and Meckel's cartilage-Meckel's cartilage (homotypic) combinations, which served as controls, became united by a common extracellular matrix and by the proliferation of chondroblasts. Analysis of combinations where one partner had been prelabelled with 3H-thymidine indicated that chondroblasts intermingled at the contact zone. In contrast, tibia-Meckel's cartilage (heterotypic) combinations became separated by a layer of fibrous tissue. The chondroblasts at the contact zone failed to intermingle. We conclude that avian embryonic chondrocytes are not all equivalent and that part of their nonequivalence could be related to their embryological origin either from the mesoderm or from the ectodermal neural crest.
Three cases of severe costovertebral deformities together with embryologically related cardiac malformations (Fallots Tetralogy and Truncus arteriosus communis) are presented. Two patients died because of their thoracic deformities and limited respiratory function. Relationships to similar bizarre veretebral anomalies are discussed. The cause is probably a teratogenic agent, acting between the fifth to eight embryologic week.
Based on findings on the molecular mechanisms of differentiation in drosophila, developmental genes have been identified in mammals similar to those in drosophila. Moreover, sequence similarities between drosophila developmental genes and mammalian growth factors provide evidence for common ancestors of such genes and suggest a complex link between growth and differentiation. As numerous oncogenes display their action as growth factors and are expressed during embryogenesis, differentiation and oncogenesis seem to be two sides of the same coin. Therefore, the aim of molecular embryology is twofold; elucidating differentiation processes and disclosing oncogenesis by studying the physiological function of oncogenes during development. Recent progress in molecular genetic technology now allows gene function to be studied by modification or disruption of genes. Models of clinical diseases have already evolved from such work and it is anticipated that progress in molecular embryology will further stimulate work on the diagnosis and therapy of genetic diseases as well as clinical oncology.
Among 34 patients with vascular rings, symptoms of tracheal and esophageal compression or both occurred during the first six months of life in 24 (71%). Diagnosis was made in all cases on either plain x-ray film or esophagogram, and was confirmed by operation or angiogram. Associated defects were numerous, with ventricular septal defect (5) and Down's syndrome (3) most common. Operative intervention was required in 18 cases (53%), including 12 of the 14 double arches. Only one of the ten patients with symptomatic recurrent subclavian artery underwent operation. Fourteen of the 18 patients operated upon had early total relief of symptoms, and 17 had excellent late results. A simple system for describing the embryology of vascular rings is presented, and the embryologic relationship between vascular rings and interrupted aortic arches is described. Because of frequent delay in recognition of vascular rings and other surgically correctable lesions, the work-up of every child with two or more episodes of pneumonia should include barium swallow.
An embryologic teratogenic mechanism is reconstructed by utilizing the distribution of anomalous ribs in children with lumbosacral myelomeningocele. This methodology may help to coalesce information from experimental models of teratogenesis and from descriptive human embryology. It provides an approach to deductive reasoning about human structural anomalies based on dynamic embryonic models of teratogenesis. Availability of a developmental time scale, based for example on the distribution of defective ribs, may be useful in the study of other teratogenic and developmental processes.
A review of 150 cases of mid-face skin cancers treated by the fresh tissue technique of microscopic controlled excision has revealed local epithelial cancer spread to be markedly influenced by embryological fusion planes. Knowledge of facial embryology which is reviewed in this article should allow the surgeon to better predict and treat mid-facial skin cancer.
This paper emphasises the need to understand the fundamentals of embryology in relation to in vitro fertilisation (IVF) and associated assisted reproductive technologies (ART). It introduces the reproductive technologist and others involved in such programmes to the events that occur during early embryogenesis, which have led to recent developments in IVF/ART. It also covers some of the contributions made by IVF/ART in understanding early events of development, particularly during the first week of human life. The reader is referred to some of the widely used embryology texts and audio-visual aids and also to selected reviews and papers published recently that would help toward a better understanding of early development and ART.
Twenty seven human embryos from stages 15 to 23 (postsomitic period), belonging to the collection of the "UFR Biomédicale des Saints-Pères, Université René Descartes Paris V", were studied. Details of the aorticopulmonary cleavage were analysed specially aortic valve development and origin of the coronary artery. At stage 18 the aortic valve was clearly distinguished (cup-shaped) presenting semilunar valves and aortic sinus (Valsalvae); at this stage the left coronary artery was detected in 66.7 per cent of the cases as an endothelial epicardial invagination. At stage 19, the left and right coronary arteries were detected simultaneously in 100 per cent of the cases. At stage 20, the coronary arteries showed greater structural complexity with a coat of mesenchymal cells. These results agree with previous data from different embryological collections. These findings suggest that the left coronary artery has a tendency to develop earlier than the right. We found no evidence of the coronary origin from the aortic lumen. This work provides additional information about the embryological development of the heart, obtained from the analyses of a French collection of human embryos.