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Histological Serial Sections (histological + serial_section)
Selected AbstractsCryptic female exaggeration: The asymmetric female internal genitalia of Kaliana yuruani (Araneae: Pholcidae)JOURNAL OF MORPHOLOGY, Issue 6 2006Bernhard A. Huber Abstract Males of the Venezuelan pholcid spider Kaliana yuruani have unique genitalia, with the procursi about six times as long as usual in the family. The present article describes the previously unknown female, searching for a morphological correlate in the female genitalia to the male's exaggeration. Reconstruction of histological serial sections reveals an internal female complexity that is unequalled in pholcid spiders. An intricate system of ducts and folds is arranged in an asymmetric way, making this the third known case of genital asymmetry in spiders. The term "cryptic female exaggeration" is used in analogy to cryptic female choice, pointing to the fact that from the outside, the female genitalia do not appear unusual. I propose that cryptic female exaggeration may be relatively common in copulatory structures if male exaggerations need to be evaluated according to the female choice by mechanical fit model. Finally, the evolution of genital asymmetry in spiders is contrasted with that in insects. J. Morphol. © 2006 Wiley-Liss, Inc. [source] Three-dimensional reconstruction of the remodeling of the systemic vasculature in early pig embryosMICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2008Pieter Cornillie Abstract Current research on angiogenesis and vascular regression is mainly focused on pathological conditions such as tumor growth and diabetic retinopathy, while a suitable physiological model to study the controlling factors in these processes is still lacking. The remodeling pattern of the embryonic vasculature into the adult configuration, such as the branchial arch arterial system developing into the aorta or the early embryonic veins building the caudal vena cava can potentially serve as a model. However, practical applications of the embryonic vascular patterning are impeded by the current controversy over the exact development of the caudal vena cava in mammals. To elucidate these ambiguities, specific developmental stages of vascular development in pig embryos were mapped by means of computer-assisted 3D reconstructions starting from histological serial sections of Bouin's fixed embryos. Special attention was given to venous segments in the lumbar region, as their origin and fate are equivocally described in literature. Here we demonstrate that these venous segments originate from the caudal cardinal veins which are forced to migrate during development into a more dorsal position due to the expansion of the developing metanephroi and the more dorsal relocation of the umbilical arteries. These findings are in contrast with the generally accepted theory that the venous segments in the lumbar region arise from newly formed veins that are located dorsal to the early caudal cardinal system. Microsc. Res. Tech., 2008. © 2007 Wiley-Liss, Inc. [source] Development of the dentition: four-dimensional visualization and open questions concerning the morphogenesis of tooth form and occlusionORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 2003RJ Radlanski Structured Abstract Author, Radlanski RJ Objectives , The formation of the dental primordial should be visualized with special reference to characteristic differences for each single primordium. Until today, it has not been clear how traffic of the ameloblasts is controlled, how the folding pattern of the occlusal relief is generated or how the enamel production is terminated at the enamel surface. Design , Using computer-aided reconstructions from histological serial sections, the dental primordial were visualized and, using fractured enamel specimens, the traces of each single ameloblast were followed by means of scanning electron microscopy. In this way, the developmental movements of the inner enamel epithelium can be reconstructed. Results , Gathering morphological knowledge, three-dimensional polygon sets of shape data were input into a computer workstation and animated by means of the software Soft Image (Microsoft). Conclusions , The development of the human primary and permanent dentition was animated to simulate growth. [source] Prenatal craniofacial morphogenesis: four-dimensional visualization of morphogenetic processesORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 2003RJ Radlanski Structured Abstract Author , Radlanski RJ Objectives , Basic research concerning craniofacial development presently runs along two pathways, namely the molecular and the morphometric. This gap needs to be bridged. Design , Using histological serial sections of human fetuses computer-aided three-dimensional reconstructions were made (Software Analysis, SIS) with special focus given to all anatomical structures of the orofacial region of the growing head. Results , All reconstructions can be viewed from any rotation and they are available for virtual dissection according to anatomical rules. As an example, the prenatal development of the human mandible with the formation of the mental foramen therein is described. Furthermore, the spatial arrangement of bone, cartilage and nerves is presented in three dimensions in different developmental stages. The interaction of tissues with possible morphogenetic interaction is discussed. Conclusions , This work serves as a reference system for prenatal development in comparison with pathological development. [source] | ||||||||||