bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructural architecture of pulmonary small‐granule cell clusters in adult syrian golden hamster
Authors: Pearsall Allan Dorland 
Published: February 2005

AbstractThroughout the epithelial lining of the respiratory system is a class of cells with characteristics similar to Amine Precursor Uptake and Decarboxylation (APUD) polypeptide hormone‐producing cells. In the intrapulmonary airways, these small‐granule cells (SGCs) occur either singly or in organized clusters. Although no specific peptide has yet been identified, subclasses have been postulated based on granule geometry or light microscopic staining. The present study characterizes the architectonic and cellular organization of clustered SGCs in the adult Syrian golden hamster. Two morphologically distinct cells can be defined in such clusters, “light” and “dark.” This distinction was based primarily on differences in the electron density of the cytoplasmic matrix rather than on the remarkable variations in cellular organelles or dense‐core secretory vesicles. Both cell types were normal as judged by uniform spherical nuclei, chromatin organization, and distribution of cellular organelles. The “dark” cells, however, presented the profile of a cell actively involved in synthesis with a markedly dilated perinuclear cisterna and endoplasmic reticulum. Additionally, the “dark” cells contained membrane‐delimited structures containing concentric membranous whorls, clear vacuoles, and lipofuscin granules. Occasionally, cells were observed to contain features of both cell types, suggesting that they may represent a continuum of common cell lineage. Accordingly, in the absence of additional morphologic or biochemical data, the “light” and “dark” cells most probably correspond to different stages of functional activity or age‐related changes of a single type of cell. Unmyelinated nerve endings were occasionally interposed between cells, but synaptic specializations were not observed. Beneath the clusters, nerve fibers were also present, but they were never observed to penetrate the basal lamina or contact any of the SGCs. Of equal occurrence were elements of the vascular system and smooth muscle, suggesting that some SGCs in the adult hamster may function in a paracrine or endocrine manner. Such knowledge is essential to any study attempting to delineate the functional role or roles of these enigmatic organoids.
Morphology of the lingual apparatus of the domestic chicken, Gallus gallus, with special attention to the structure of the fasciae
Authors: Homberger Dominique G. , Meyers Ron A. 
Published: February 2005

AbstractA detailed redescription of the mechanically interacting structural elements of the lingual apparatus of the domestic chicken, Gallus gallus, revealed the functional and constructional role of organized connective tissue (i.e., ligaments and fasciae) as structural elements that ensure the proper biomechanical interactions among the various structures within the lingual apparatus (e.g., cartilaginous and bony skeletal elements, muscles, salivary glands, epithelial structures). Fasciae, together with extrinsic muscles, also connect the lingual apparatus to the other components of the feeding apparatus, such as the skull, jaw apparatus, and larynx. For example, the hyoid apparatus is attached to the skull by a sheath‐like fascia (F. vaginalis), the internal structure of which is described here for the first time. Thus, the hyoid suspension in birds differs fundamentally from that in mammals.This study is the first to examine all biomechanically functioning structural elements that are part of the galliform lingual apparatus in a systematic and comprehensive manner. It also provides a set of novel characters that may be useful for future comparative studies in evolutionary and functional morphology.
Post natal development of the neck system in the chicken (Gallus domesticus)
Authors: Heidweiller Jan 
Published: February 2005

AbstractThe lengths of several neck muscles and tendons and the length, width, and height of the cervical vertebrae and some additional distances were measured in the chicken in six post‐hatching ontogenetic stages and adults. Each vertebra is characterized by a unique combination of growth rates. All increase most in length. Cranial and caudal width as well as height decreases relative to length during ontogeny. When the long dorsal neck muscles are assumed to provide the support for the weight of the head and half of the weight of the neck, the neck system evidently develops according to McMahon's elastic similarity theory. The assumption is justified also because the weights of head and neck together appeared to scale as predicted by elastic similarity. Short neck muscles show negative and tendons positive allometric growth, and long neck muscles grow isometrically relative to neck length. This growth pattern of the muscles and tendons is a direct consequence of the geometric relations of the different growth rates of the vertebrae.
Development of arteriovenous anastomoses in the skin of the chicken and the influence of environmental temperature
Authors: Midtgård Uffe 
Published: February 2005

AbstractPosthatching differentiation of arteriovenous anastomoses (AVAs) and the effect of heat exposure (38°C) and cold acclimation (2–3°C) on AVA density were studied in naked skin areas (eyelids, comb, wattles) of chickens. The AVAs were identifiable in the newly hatched chick, but they were extremely simple. The number of cell layers in the wall of the AVAs increased from two at hatching to four to five in the 5‐month‐old chickens. The density of the AVAs increased significantly during posthatching maturation. Cold acclimation of the chickens increased the density of AVAs by a factor of 2.1–3.2. Daily heat exposure also increased the density of AVAs significantly in the eyelids but had no effect in the other skin areas. Heat and cold had only minor effect on the vascularity of the skin; the only significant change recorded was a slight increase in the number of blood vessels in the wattles of the cold‐acclimated chickens.
Comparative morphology and morphometry of the nasal fossae of four species of North American shrews (Soricinae)
Authors: Larochelle Renée , Baron Georg 
Published: February 2005

AbstractThe present study compares the morphology of the nasal conchae and the relative development (i.e., surface area and neurosensory cell number) of the olfactory epithelium between four species of shrews occupying different ecotopes (Blarina brevicauda, Sorex cinereus, S. fumeus, S. palustris). The number of olfactory cells was corrected for split cell error. Data were analyzed by using size indices based on the allometric method. The convoluted shape of the maxilloturbinal in Blarina, with large respiratory epithelial surface area, could not be related with certainty to the subterranean ecotope. From the comparison between Soricinae and Crocidurinae, one major difference concerned the shape and attachment of ectoturbinal 3.Differences in the relative development of the olfactory organ are discussed with regard to differences in the use of chemical signals. The semi‐fossorial B. brevicauda, with the more developed olfactory organ, is reported to possess more scent‐glands and to manifest active scent‐marking behaviors and fecal deposits associated with territoriality. The two terrestrial species, S. cinereus and S. fumeus, have olfactory epithelia showing an intermediate development. Published accounts of fewer scent‐glands and a lack of active scent‐marking behavior indicate a lesser use of olfactory communication in these two species where mutual avoidance seems the rule. Indication of an even more reduced use of olfactory signals in social interactions by the semiaquatic S. palustris is suggested by its least‐developed olfactory epithelium. The comparison between Soricinae and Crocidurinae supports a relationship between the development of the olfactory organ and the relative use of olfactory communication known to occur in social interactions.
Scales in young Polypterus senegalus are elasmoid: New phylogenetic implications
Authors: Sire Jean‐Yves 
Published: February 2005

AbstractA component of the basal plate which has a plywood‐like organization similar to that of the elasmoid scales of teleosts is described in the scales of Polypterus senegalus for the first time. The origin and development of this structure is studied in young (50–117 mm, standard length) and adult (225 and 240 mm) specimens using light and electron microscopy. In 50 mm fish, the scales are imbricated and composed mainly of a succession of orthogonal collagen layers forming a plywood‐like structure, the isopedin. The outer surface of the scale is ornamented locally by irregular patches of collagenous material. The layers are not mineralized, whereas the superficial patches are well calcified. The isopedin thickens until it has 12–15 layers and then stops growing (88 mm fish). It mineralizes irregularly from its upper part, and two vascular regions, surrounded by woven‐fibered osseous material, form on the outer and deeper surfaces of the isopedin. These regions thicken while the vascular canals close by centripetal deposition of parallel‐fibered osseous tissue. The outer region is the superficial part of the mature scale (called here osteodentin), which is covered by the ganoine deposited by the epidermal cells. The deeper part constitutes the definitive basal plate, composed of parallel‐fibered osseous tissue. The results show (1) that the young ganoid scales of Polypterus senegalus have a structure similar to that of typical elasmoid scales; and (2) that the isopedin structure does not change during ontogeny and so represents a permanent record of the first ontogenetic stages. The phylogenetic implication of these results is that the elasmoid scales of teleosts arose by a process of paedomorphosis.
Osteoclast biology in the osteopetrotic (op) rat
Authors: Marks Sandy C. , Popoff Steven N. 
Published: February 2005

AbstractOsteopetrosis is a metabolic bone disease characterized by reduced bone resorption. From experimental studies of various osteopetrotic mutations has emerged the hypothesis that each is unique with respect to mechanisms whereby osteoclast development and/or function are reduced. The osteopetrotic (op) mutation in the rat was discovered in Fatty/ORL stock over a decade ago. The paucity of data about osteoclast biology in this mutation prompted this study of cytological, cytochemical, and ultrastructural features of osteoclasts. In op rats, osteoclasts are significantly reduced in number, but are larger and more vacuolated than in normal littermates. Mutant osteoclasts can form ruffled borders and clear zones, but their ability to fragment and excavate bone surfaces is greatly impaired. Cytoplasmic vacuoles in op osteoclasts are randomly distributed and greatly enlarged, and they stain weakly for two cytochemical characteristics of osteoclasts, tartrate‐resistant acid phosphatase and acid ATPase. These findings suggest that an abnormality in the lysosomal/vacuolar system, an important component of the resorptive mechanism, may be involved in the interception of osteoclast function in this mutation.
Eosinophils and mast cell homogeneity of the guinea pig eyelid skin, conjunctiva, and ileum
Authors: Stock E. Lee , Hill Richard A. , Boyle‐Vavra Susan , Roth Sanford I. 
Published: February 2005

AbstractMast cell heterogeneity has been described on the basis of differential staining reactions, light microscopic morphology, anatomic location, degranulation after polyamines, biochemical contents, growth requirements, and reactions to lymphokines. We have demonstrated typical “connective‐tissue mast cells” by using anatomic criteria, histological staining reactions, electron microscopy, and reaction to compound 48/80 in the guinea pig conjunctiva, eyelid skin, and ileum. A second, much larger population of cells in the ileal mucosa and the conjunctiva, and rarely in the eyelid skin stained reddish‐blue with acid toluidine blue in tissue fixed in ethanol‐acetate‐lead subacetate (BLA) and with alkaline Giemsa in formaldehyde‐fixed tissue, did not stain with ethanolic or acid toluidine blue in formaldehyde‐fixed tissue or with alkaline Giemsa in BLA‐fixed tissue, and did not degranulate after 48/80 treatment. These are features of the rat intestinal “mucosal mast cells”; however, ultrastructural and light microscopic studies with the orcein Giemsa stain demonstrated these cells in the guinea pig to be eosinophils. Tissue culture, biochemical, and immunological studies indicate the existence of a second type of mast cell (bone‐marrow‐derived mast cell), ultrastructurally almost indistinguishable from the connective tissue mast cell. Our studies demonstrate only one mast cell type in the guinea pig and support the contention that other forms of mast cells are immature forms or variants of the connective‐tissue mast cell.
Postnatal development of vascularity in the inferior colliculus of the young rat
Authors: Andrew D. L. E. , Paterson J. A. 
Published: February 2005

AbstractThe inferior colliculus in the rat midbrain is an auditory relay center whose functional maturation occurs postnatally. We examined by morphometry the vascularity and the nuclear profile density of the inferior colliculus in normal young rats at different ages (before and after the onset of auditory input). We also compared this region with a frontal region of the cerebral cortex in 24‐day‐old rats. The inferior colliculus from aldehyde‐perfused Sprague‐Dawley rats aged 5, 9, 14, and 24 days was analyzed by light microscopy of semithin plastic sections. The central region (mostly the central nucleus) was sampled at 5 levels representing its entire rostrocaudal extent. Patent‐blood‐vessel profiles were counted and classified according to their size and profile orientation. Counts of nuclear profiles in the same sections were also made. In the inferior colliculus of rats between 5 and 24 days of age, the small (>10‐μm diameter) cross‐sectioned vessel profiles increased over 6‐fold in number per unit area. Correspondingly the vascular volume density, estimated by differential point counting, increased between these ages. However, there was a decrease in the number of neuronal and glial nuclear profiles per unit area, probably because of growth in the volume of the neuronal perikarya and processes, along with cell emigration reported to occur at early postnatal ages. This study has shown that an increase in vascularity in the central region of the rat inferior colliculus continues for up to 2 weeks after the onset of hearing. The numerical density of small vessels in the rat inferior colliculus had reached the adult level of vascularity by 24 days of age. Also, by 24 days and possibly earlier, regional differences in capillary density in the brain were evident; the frontal cortex was found to have fewer small vessel profiles per unit area and a lesser vascular volume density than the inferior colliculus. Thus, such micro‐regional differences in vascularity must have arisen earlier during brain and capillary growth.
Distribution of endogenous albumin across the rat aortic wall as revealed by quantitative immunocytochemistry
Authors: Londoño Irene , Bendayan Moise 
Published: February 2005

AbstractEndogenous albumin was revealed over thin sections of rat aortic wall, with high resolution and specificity, by applying the protein A–gold immunocytochemical technique. Gold particles, revealing albumin antigenic sites, were observed over plasmalemmal vesicles in endothelial cells and over the interstitial space throughout the thickness of the aortic wall. The distribution of the labeling in the interstitial space varied from region to region and was associated with the collagen fibers, following the orientation of the bundles. The morphometric evaluation of this labeling demonstrated a first peak in labeling intensity in the intima followed by a steep decrease with low levels in the media, and an increasing gradient towards the adventitia. In the subendothelium, a moderate labeling was observed at the base of the endothelial cells of both aortic and capillary endothelia, followed by a decreasing gradient. Ratios between the labeling density in the intima as well as in the adventitia and that in the capillary lumen (plasma albumin) revealed different concentrations of albumin in these compartments. Endogenous albumin, under steady‐state conditions, is thus unevenly distributed over the interstitial spaces across the rat aortic wall, and appears associated along the collagen fibers.
Diameter increase of collagen fibrils of the mouse endometrium during decidualization
Authors: Alberto‐Rincon Maria C. , Zorn Telma M. T. , Abrahamsohn P. A. 
Published: February 2005

AbstractThe diameter of collagen fibrils was measured in different regions of the antimesometrial endometrium of mice on days 5, 6, and 7 of pregnancy as well as in the endometrium of virgin mice. The average diameter of fibrils of virgin mice was 39.18 nm (range: 20–80). In the region of fully decidualized cells, the averages and ranges were 45.32 nm (30–170), 89.39 nm (30–270), and 125.88 nm (20–370), respectively, on days 5, 6, and 7 of pregnancy. Thick fibrils larger than 70 nm had irregular profiles. Our results show that the increase in diameter is associated with the decidualization of the mouse endometrium.
Differentiation of cyclophosphamide‐treated hamster secondary palate: Ultrastructural and biochemical observations
Authors: Shah Ravindra M. 
Published: February 2005

AbstractA study was undertaken to analyze the ultrastructural aspects and the enzyme acid phosphatase cytochemistry and biochemistry of the pathogenesis of cyclophosphamide (CP)‐induced cleft palate in hamster fetuses. The initial CP‐induced alterations were the appearance of lysosomes in the mesenchymal cells of the vertically developing palatal primordia within 8 hr of drug administration. The mesenchymal lysosomal activity, which increased during the next 16 hr, was abnormal and interpreted as a sub‐lethal response to CP treatment. Subsequently, the lysosomal activity in the mesenchyme diminished gradually and, 48 hr after CP treatment, was absent. At this time, lysosomes were seen in the epithelial cells of the vertical palate. Fifty‐six hours after CP treatment, unlike controls where palatal shelves were already fused, lysosomal activity subsided in the epithelial cells. Changes, however, continued to be seen at the epithelial‐mesenchymal interface. These changes were characterized by discontinuity in the basal lamina, and by epithelial‐mesenchymal contacts. They persisted for 8 hr but were absent thereafter. Sixty‐four hours after CP administration, the vertical shelves became horizontal and remained so until term. Following analysis of data, both from the literature and from the present study, it was suggested that CP first affected mesenchymal cell proliferation, and then its cytodifferentiation, during the critical phase of early vertical development; consequently the reorientation of the shelves to a horizontal plane was delayed, inducing celft palate.
Prenatal development of “synaptic” ribbons in the guinea pig pineal gland
Authors: Luo Z. R. , Schultz R. L. , Whitter E. F. , Vollrath L. 
Published: February 2005

AbstractPineal “synaptic” ribbons are a heterogeneous population of organelles. “Synaptic” ribbons (SR) sensu stricto, “synaptic” spherules (SS), and intermediate forms (IMF) are present. Their function and origin are unknown, and a knowledge of their prenatal development is lacking. Thus the pineal glands of prenatal, neonatal, and adult guinea pigs were prepared for electron microscopy. “Synaptic” ribbons were studied morphologically and quantitatively. The three categories of “synaptic” ribbons reported in adult pineal glands were also present in prenatal pineal glands. Their structural features, distribution, grouping, and composition patterns are similar to those in adults. “Synaptic” ribbons were first detected in pinealocytes of the distal region of a 42‐day postcoitus (PC) pineal gland and were comparable with those in adults. They increased in number with age and reached a peak at 63 days PC, followed by a steep decline at 66 and 67 days PC. By day 69 PC, the numbers increased again and showed a dramatic increase after birth. Several true ribbon synapses were seen at day 63 PC between pinealocyte cell processes or between pinealocyte cell process and pinealocyte cell body. Since true ribbon synapses have not been found in adult guinea pig pinealocytes, their synaptic nature could have been lost during development. No precursors for the “synaptic” ribbons were found. The endoplasmic reticulum cisternae may be the origin for the ribbon vesicles because of their close association with the “synaptic” ribbons.
Peripheral development of avian trigeminal nerves
Authors: Kuratani Shigeru , Tanaka Shigenori 
Published: February 2005

AbstractDevelopment of the trigeminal nerve branches was studied in stage ‐17 to ‐27 chick embryos stained with an antibody to neurofilament protein. The following findings were obtained. (1) Ectopic ganglia transiently appeared in the ectoderm of the supraorbital region and were considered as remnant ophthalmic‐placode‐derived ganglia. (2) Most of the cutaneous sensory branches of the maxillomandibular nerve arose from a loosely arborized mass of neurites, provisionally termed the maxillomandibular reticulum, in which the fibers intermingled in a seemingly random fashion. (3) The growth of the trigeminal branches was mainly correlated with the development of the facial processes; however, irregular communications between different groups of branches were observed, suggesting that topographical organization of the peripheral branches is not rigid in early stages. (4) From the ophthalmic nerve around stage 23, transient dorsal rami developed and were distributed in the mesenchymal space, the cavum epiptericum, and passed near the ectoderm. Their homology with the rr. tentorii in human anatomy is suggested.
Ontogenetic development of the ophthalmic rete in relation to brain cooling in chickens and pigeons
Authors: Arad Zeev , Midtgard Uffe 
Published: February 2005

AbstractThe brain cooling capacity of the altricial pigeon increases during posthatching growth at a higher rate than that of the precocial duck and chicken. To determine if this difference between the altricial and the precocial modes of development can be related to growth rates of the vascular heat exchanger involved in brain cooling (the ophthalmic rete), we performed a morphometric analysis of this structure during the posthatching maturation of the three species. The number of vascular units in the rete did not change during development but differed significantly among species. The retia continued to grow in length and diameter in an exponential relation with body mass at similar rates in all species. The surface area of the retial arteries, which reflects the area available for countercurrent heat exchange, also increased exponentially with body mass, but without significant differences among the three species. However, the effectiveness of the rete in brain cooling, as indicated by the degree of brain cooling per unit of heat‐exchange area in the rete, was higher in the altricial pigeon than in the precocial chicken and duck. It is concluded that the posthatching morphometric changes in the ophthalmic rete (rete ophthalmicum) are important for the development of brain cooling capacity, but cannot solely explain differences in brain cooling between growing altricial and precocial birds. These differences are most likely related to differences in the maturation of the central thermoregulatory control system and the peripheral effector mechanisms among the two groups of birds.