bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prenatal and postnatal development of the small intestine in the insectivore Suncus murinus
Authors: Kiso Yasuo , Oku Kazuomi , Yamauchi Shoji 
Published: February 2005

AbstractThe development of the small intestine in the insectivore Suncus murinus was noted during the period from 21 days' gestation to 20 clays after birth. At 21 days of gestation, the proximal small intestine exhibited the beginning of villus formation, whereas the distal small intestine preserved the stratified epithelium. Stratified epithelium in the distal small intestine changed into a single layer by 24 days' gestation. At 26 day's gestation, each epithelial cell was immature; but by 28 days mature‐looking epithelial colls were found. The shape of the villi changed from cuboid to columnar during the same period. The connective‐tissue cores of the villi began to develop at 7 days after birth in the proximal small intestine and at 15 days after birth in the distal small intestine. Crypts appeared at 15 days after birth.Endocytosis of epithelial cells took place at 28 days of gestation. In the proximal small intestine, supranuclear vesicle clusters were observed first at birth; they began to decrease both in number and size at 10 days' gestation and then disappeared completely by 20 days after birth. In the distal small intestine, large supra‐nuclear vacuoles were observed first at 28 days of gestation. Although these vacuoles invariably were found up to 15 days after birth, they also disappeared completely by 20 days. Epithelial cells showed a structure similar to those of the adult after weaning.
Formation of secretion granules in the Golgi apparatus of pancreatic acinar cells of the rat
Authors: Rambourg A. , Clermont Y. , Hermo L. 
Published: February 2005

AbstractThe three‐dimensional structure of the Golgi apparatus and its components has been analyzed in sections of pancreatic acinar cells by using stereopairs of electron microscope photographs. Pancreatic tissue fixed in glutaraldehyde was postfixed in reduced osmium, and the sections were stained with lead citrate. Tissues were also treated to demonstrate phosphatase activity (i.e., nicotinamide adenine dinucleotide phosphatase, NADPase; thiarnine pyrophosphatase, TPPase; cytidine monophosphatase, CMPase). The following stacked components were observed along the branching, anastomotic, continuous, ribbon like Golgi apparatus. (1) On the cis‐face of the Golgi stack there was a tubular membranous network known to be osmiophilic and referred to as the cis‐osmiophilic tubular network or cis‐element. (2) A first, poorly fenes‐trated saccule, unreactive for the phosphatases tested, was slightly distended in places and contained a fluffy granulofilamentous material. (3) The subjacent three or four saccules, reactive for NADPase and/or TPPase, showed dilated portions containing a granulofilamentous secretory material similar to that filling the rest of the saccule. They also showed nondilated portions perforated with large fenestrations, some of which were in register and formed wells containing 80‐nm vesicles. The dilated portions of these saccules were present at random along the length of the saccules and were not located exclusively at their edges. (4) The remaining one or two elements of the stack, CMPase positive, showed dilated spheroidal portions or prosecretory granules containing a homogeneous secretory material and flattened fenestrated regions free of secretory material and having the appearance of networks of narrow membranous tubules. (5) Lastly on the trans‐aspect of the stack there were detached prosecretory granules reactive for CMPase and surrounded by a corona of small vesicles, and smooth‐surfaced spherical CMPase‐negative granules having a denser content that were identified as fully formed secretion granules; there were also occasional free trans‐tubular networks strongly reactive for CMPase that appeared to undergo fragmentation and numerous small vesicles free from acid‐phosphatase activity. These various images were interpreted as indicating that prosecretory granules formed in relation to two or three fenestrated saccules on the trans‐side of the stack. Such granules, following their detachment from the trans‐face of the stack, their separation from trans‐tubular networks, and condensation of their content, yielded mature secretion granules.
Histology and functional morphology of the female reproductive tract of the tortoise Gopherus polyphemus
Authors: Palmer B. D. , Guillette L. J. 
Published: February 2005

AbstractThe oviducts of 25 tortoises (Gopherus polyphemus) were examined by using histology and scanning electron microscopy to determine oviduc‐tal functional morphology. Oviductal formation of albumen and eggshell was of particular interest.The oviduct is composed of 5 morphologically distinct regions; infundibulum, uterine tube, isthmus, uterus, and vagina. The epithelium consists of ciliated cells and microvillous secretory cells throughout the oviduct, whereas bleb secretory cells are unique to the infundibulum. The epithelium and endometrial glands of the uterine tube histologically resemble those of the avian magnum which produce egg albumen and may be functionally homologous. The isthmus is a short, nonglan‐dular region of the oviduct and appears to contribute little to either albumen or eggshell formation.The uterus retains the eggs until oviposition and may form both the fibrous and calcareous eggshell. The endometrial glands are histologically similar to the endometrial glands of the isthmus of birds, which are known to secrete the fibers of the eggshell. These glands hypertrophy during vitellogenesis bin, become depleted during gravidity. The uterine epithelium may supply “plumping water” to the egg albumen as well as transport calcium ions for eggshell formation. The vagina is extremely muscular and serves as a sphincter to retain the eggs until oviposition.Sperm are found within the oviductal lumen and endometrial glands from the posterior tube to the anterior uterus throughout the reproductive cycle. This indicates sperm storage within the female tract, although the viability and reproductive significance of these sperm are unknown.
Roots and calibers of the human coronary arteries
Authors: Zamir M. , Sinclair P. 
Published: February 2005

AbstractThe anatomical structure of the coronary‐aortic junctions in humans is studied by using corrosion casts of the coronary network. A model is proposed for the specification of these junctions in terms of vessel diameters and branching angles, and the model is used to produce morphological data on these junctions which hitherto have not been available. This anatomical model correlates poorly with the accepted theoretical model of arterial bifurcations in the cardiovascular system. The results suggest that the structure of the coronary‐aortic junctions is very different from the structure of typical arterial bifurcations and, by implication, that the flow conditions under which they function are very different. A good understanding of these junctions is important in coronary bypass surgery, where the coronary‐aortic junctions are emulated by creating a new anastomosis for the graft at the base of the ascending aorta, and in coronary artery disease, where atherosclerotic lesions occur not far from the coronaiy‐aortic junctions.
Ultrastructural features of chloride cells in the gill epithelium of the atlantic salmon, Salmo salar, and their modifications during smoltification
Authors: Pisam M. , Prunet P. , Boeuf G. , Jrambourg A. 
Published: February 2005

AbstractTo elucidate the ultrastructural modifications of the gill epithelium during smoltification, gills of the Atlantic salmon (Salmo solar) were examined by electron microscopy at three stages of this process, which were defined as follows: “parrs” were freshwater fish that had not yet started their transformation; “freshwater smolts” were freshwater fish that were ready to enter seawater; and “seawater smolts” were smolts that had been transferred from fresh water and maintained for 4 days in seawater (35%).In the gill epithelium of parrs, there were two types of chloride cells. The large chloride cells contained deeply stained mitochondria and numerous apical, irregular, dense, membrane‐bound bodies that formed 77% of the chloride cell population and were distinguished easily from small chloride cells that have distinctly paler mitochondria and no dense bodies in their apical cytoplasm. In freshwater smolts, the large chloride cells formed 95% of the chloride‐cell population. In contrast to the small chloride cells that were not modified, they almost doubled in size. Their tubular system developed extensively to form a tight network with regular meshes significantly smaller than those observed in parr chloride cells. Forty percent of the large chloride cells were associated with a new type of cell, the accessory cell, to which they were bound by shallow apical junctions. Half of these accessory cells were not seen to be in contact with the external medium, In seawater smolts, 80% of the large chloride cells were associated with accessory cells. Most accessory cells reached the external medium and sent numerous cytoplasmic interdigitations within the apical portion of the adjacent chloride cells. As a result, a section through the apical portion of the chloride cells and their associated accessory cells revealed a mosaic of interlocked cell processes bound together by an extended, shallow apical junction.It was concluded that the Atlantic salmon develops in fresh water most of the ultrastructural modifications of the gill epithelium which in most euryhaline fish are triggered by exposure to seawater. The effective transfer into seawater would act only as a final stimulus to achieve some adequacy between the freshwater smolt and its new environment.
Morphology and morphometry of the normal lung of the adult vervet monkey (Cercopithecus aethiops)
Authors: Maina J. N. 
Published: February 2005

AbstractThe lungs of four adult specimens of the vervet monkey (Cercopithecus aethiops) have been examined by transmission and scanning electron microscopy. A morphometric evaluation of the structural components directly involved in gas exchange has been carried out and the data have been modelled to estimate the anatomical diffusing capacity of the lung. The upper air‐conducting airways of the lung were lined by an epithelium characterized by ciliated cells among which were dispersed goblet cells. The alveolar surface was lined by squamous type I pneumocytes and cuboidal type II granular pneumocytes. The blood‐gas (tissue) barrier consisted of an epithelial cell, a common basal lamina, and an endothelial cell in the thin parts of the interalveolar septum. In the thicker parts of the septum, an interstitial space interposed between the basal laminae of the epithelial and endothelial cells contained supportive elements such as collagen, elastic tissue, and fibrocytes. The alveoli, the blood capillaries, and septal tissue composed 73%, 16%, and 11%, respectively, of the parenchyma. The harmonic and arithmetic mean thicknesses of the blood‐gas (tissue) barrier were 0.311 μm and 1.048 μm the surface area of the blood‐gas (tissue) barrier per unit body weight was 50 cm2g−1, and the surface density was 117 mm2‐mm3−1.The weight‐specific total morphometric diffusing capacity was 0.11 mlO2 (sec·mbar·kg)−1. In comparison, the pulmonary morphometric characteristics of vervet monkey lung were superior to those of the other primates (Macaca irus, M. mulatta, and Homo sapiens) for which equivalent data are available. The gas‐exchange potential of the lungs of the nonhuman primates as revealed by morphometric studies surpasses that of man, a feature that can be attributed to the relatively less energetic human lifestyle.
Occurrence of lymphohaemopoietic tissue in the meninges of the stingray Dasyatis akajei (Elasmobranchii, Chondricthyes)
Authors: Chiba A. , Torroba M. , Honma Y. , Zapata A. G. 
Published: February 2005

AbstractThe cytoarchitecture of the lymphohaemopoietic masses occurring in the “meninx primitiva” of the stingray Dasyatis akajei (Elasmobranchii, Chondricthyes) has been analyzed by light and scanning and transmission electron microscopy. Lymphohaemopoietic aggregates showing similar morphologies occurred along all the central nervous system, but they were more frequent in the telencephalon, diencephalon, and mesencephalon. In each aggregate, the granulopoietic tissue appeared in a fibroblastic stroma surrounding the large blood vessels, and the lymphoid components were present in a reticular network. Developing and mature eosinophils and heterophils–as well as lymphocytes, monocytes, macrophages, and plasma cells–are the main free cells present in these meningeal aggregates. The remarkable intimate association between macrophages and lymphoid cells to form close cell clusters suggests some immunological capacity for the meningeal lymphohaemopoietic tissue. According to their capacities, presence of lymphoid tissue, and histological organization, the meningeal lymphuhemopoietic aggregates of Dasyatis akajei resemble other lymphomyeloid aggregates associated with cranium and choroid plexuses in Holocephali and Ganoidei. The phylogenetical relationships of these aggregates with mammalian bone marrow are discussed.
Ontogeny of architectural complexity in embryonic quail visceral arch muscles
Authors: McClearn Deedra , Noden Drew M. 
Published: February 2005

AbstractUnderstanding the mechanisms of muscle pattern formation requires that the complete sequence of ontogenetic events be defined, particularly in the emergence of architectural complexity and in the spatial relations between muscles and skeletal elements. This analysis of visceral arch myogenesis in quail (Coturnix coturnix japonica) embryos identifies the location of premuscle condensations and subsequent segregation of individual muscles, documents the initial orientation of myofibers and changes in alignment associated with maturation, and describes the spatial and temporal relations between muscle development and the formation of connective tissues.Premuscle condensations form within the visceral arches on embryonic days 2–4, before skeletal elements make their appearance. Discrete muscles may form from the subdivision of a muscle mass after fiber orientations have been established (e.g., jaw adductor and hyobranchial muscles) or by the segregation of a mesenchymal cluster from the condensation prior to the appearance of oriented fibers (e.g., protractor, muscle of the columella).The rate and pattern of subsequent muscle maturation are closely associated with the development of the hard tissues. Myogenesis in 4–9‐day embryos centers around the quadrate cartilage, the retroarticular process of the mandibular (Meckel's) cartilage, and the epibranchial cartilage. Muscles form attachments on these elements and remain without additional attachments until the appropriate elements (e.g., otic capsule, pterygoid bone) develop. No single description of myogenic events applies to all visceral arch muscles, nor is there an arch‐specific pattern of ontogeny. Rather, each muscle has distinctive characteristics based on its spatial relations within the developing head.
Application of glial fibrillary acidic protein immunohistochemistry in the quantification of astrocytes in the rat brain
Authors: Faddis Brian T. , Vijayan Vijaya K. 
Published: February 2005

AbstractImmunohistochemical staining for glial fibrillary acidic protein (GFAP) was employed as a tool for quantification of astrocytes in the rat brain. One‐micron‐methacrylate sections were prepared from 70‐μm slices stained for GFAP by using a preembedding staining procedure. Numbers/unit area of astrocytes and nonastrocytes were determined for cortex, corpus callosum, and hippocampal neuropil. In each, counts from GFAP‐stained, toluidine‐blue‐counterstained sections were compared with counts obtained from sections stained with toluidine blue alone. Numbers of nonastrocytes and total glia in all three regions were comparable in both groups of sections. Astrocyte counts in the cortex and hippocampus also showed no significant differences between the two groups. In contrast, the number of astrocytes in the corpus callosum was significantly lower in GFAP‐stained, toluidine‐blue‐counterstained sections than in sections stained with toluidine blue alone. GFAP immunohistochemistry is a useful tool for the quantification of astrocytes in semithin plastic sections of rat brain.
Orthogonal arrays of intramembrane particles in the supporting cells of the guinea‐pig vestibular sensory epithelium
Authors: Saito Kogaku 
Published: February 2005

AbstractMembrane specializations of the contact region between afferent nerve endings and supporting cells of the sensory epithelia of guinea‐pig vestibular endorgans were examined by thin‐section and freeze‐fracture electron microscopy. The calyx‐type nerve endings (C‐endings) are separated from supporting cells (SC) by a 25–30 nm space. At irregular intervals along the upper lateral surface of supporting cells, the intercellular space narrows markedly to form special close contacts between the C‐ending and SC plasma membranes. Freeze‐fracture replicas reveal membrane specializations—orthogonal arrays of particulate units—in the region where the close intercellular contacts were found in sections. Orthogonal arrays consisting of from 5 to 20 units were observed on the cytoplasmic (P) fracture face of the lateral SC plasma membrane. These particulate units form a 12 × 12‐nm square, and each unit is composed of four 6‐nm subunits. Possible roles of the orthogonal arrays are discussed.
Early stages of spinal ganglion formation during tail regeneration in the newt, Notophthalmus viridescens
Authors: Géraudie J. , Nordlander R. , Singer M. , Singer J. 
Published: February 2005

AbstractStages in the development of sensory ganglia in the regenerating newt tail after amputation are described by taking advantage of the rostrocaudal developmental gradient of the regenerating tail. A series of ganglia, beginning at the tip of the regenerate and progressing rostrally, were examined. Eight‐week regenerates were used because they showed the most complete array of stages. The first recognizable ganglia appear as small clusters of cells sitting dorsally on the already established ventral roots. The cluster of ganglionic cells steadily expands with the addition of many new cells. Signs of cell differentiation within the ganglion precede the formation of the dorsal root rudiment, which assumes several different configurations but most commonly enters the cord close to the ventral root. Our material suggests that ganglion precursor cells originate in the ventral region of the developing spinal cord and migrate out of the cord by travelling along the ventral root until, at a suitable distance from the cord, they halt, proliferate, and eventually differentiate. In the regenerate, we saw no evidence of neural crest cells—such as those that give rise to ganglia in the trunk region during development—forming at the dorsal region of the regenerated neural tube. Nor was there any morphological evidence of mesenchymal contribution to the ganglion cell clusters.
Myofiber turnover is used to retrofit frog jaw muscles during metamorphosis
Authors: Alley Keith E. 
Published: February 2005

AbstractMetamorphic reorganization of the head in anuran amphibians entails abrupt restructuring of the jaw complex as larval feeding structural lM transformed into their adult configurations, In this morphometric study, light microscopy was used to analyze the larval maturation and metamorphic transfiguration of the adductor jaw muscles in the leopard frog (Rana pipiens). Larval jaw muscles, first established during embryogenesis, continue to grow by fiber addition until prometamorphosis, stage XIL Thereafter, fiber number remains stable but additional muscle growth continues by hypertrophy of the individual fibers until metamorphic climax. During metamorphic stages XIX‐XXIII, a complete involution of all larval myofibers occurs. Simultaneously, within the same muscle beds, a second wave of myogenesis produces myoblasts which are the precursors of adult jaw myofibers. New muscle fibers continue to be added to these muscles well after the completion of metamorphosis; however, the total duration of the postmetamorphic myogenic period has not been defined. These observations provide clear evidence that the entire population of primary myofibers used in larval oral activity disappears from the adductor muscle beds and is replaced by a second wave of myogenesis commencing during climax. These findings indicate that the adductor jaw muscles are prepared for adult feeding by a complicated cellular process that retrofits existing muscle beds with a completely new complement of myofibers.
Tracheobronchial epithelium in the adult rhesus monkey: A quantitative histochemical and ultrastructural study
Authors: Plopper C. G. , Heidsiek J. G. , Weir A. J. , St. George J. A. , Hyde D. M. 
Published: February 2005

AbstractPrevious studies of the intrapulmo‐nary conducting airways of sheep and rabbit have demonstrated marked diversity in the epithelial populations lining them. Because studies of trachea and centriaci‐nar regions of macaque monkeys suggested that primates may be even more diverse, the present study was designed to characterize the epithelial population throughout the airway tree of one primate species, the rhesus monkey. Trachea and intrapulmonary airways of the right cranial and middle lobes of glutaraldehyde/ paraformaldehyde‐infused lungs of five adult rhesus monkeys were microdissected following the axial pathway. Each branch was assigned a binary number indicating its specific location within the tree. The trachea and six generations of intrapulmonary airway from the right cranial lobe were evaluated for ultrastructure and quantitative histology as were those of the right middle lobe for quantitative carbohydrate histochemistry. Four cell types were identified throughout the tree: ciliated, mucous goblet, small mucous granule, and basal. The tallest epithelium lined the trachea; the shortest, the respiratory bronchiole. The most cells per unit length of basement membrane were in proximal intrapulmonary bronchi; the least, in the respiratory bronchiole. The nonciliated bronchiolar epithelial or Clara cell was restricted to respiratory bronchioles. Sulfomucins were present in the vast majority of surface goblet cells in the trachea and proximal bronchi. In proximal bronchi, neutral glycoconjugates predominated in glands and acidic glycoconjugates in surface epithelium. In terminal and respiratory bronchioles the ratio of acidic gly‐coconjugate to neutral glycoconjugate equaled that in proximal bronchi, although glands were not present. Sulfomucins were minimal in terminal airways. We conclude that the characteristics of the epithelial lining of the mammalian tracheobronchial airway tree are very species‐specific. The lining of the rhesus monkey does not have the diversity in cell types in different airway generations observed in sheep and rabbit. Also, the populations lining these airways in the rhesus are very different from either the sheep or rabbit in number, proportions of different cell types, glycoconjugate content, and distribution of specific cell types.