bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution of type IV collagen, laminin, and fibronectin during maxillary process formation in the chick embryo
Authors: Xu Zenglu , Parker Susan B. , Minkoff Robert 
Published: February 2005

AbstractThe presence and distribution of laminin, type IV collagen, and fibronectin were analyzed in the facial primordia and developing primary palates of chick embryos from stages of development corresponding to maxillary process formation and primary palate closure. Frozen sections through the maxillary process and roof of the stomodeum were prepared for indirect immunofluorescence employing a biotin‐avidin system using monoclonal antibodies against laminin, type IV collagen, and fibronectin. Light microscopic examination of sections stained with antibodies against type IV collagen revealed a much stronger fluorescent signal in the roof of the stomodeum than in the maxillary process at all stages examined. Regional differences in signal intensity and staining patterns were noted within the maxillary process; for example, the lateral surface of the maxillary process displayed a much less intense signal at most stages examined than the inferior and medial surfaces. The signal from sections of the maxillary process stained with laminin was much stronger than the signal from the same tissues stained with collagen. Regional differences in signal intensity within the maxillary process were minimal in sections stained with antibodies to laminin, in contrast to the differences seen in sections stained with antibodies to type IV collagen. Differences in signal intensity between the maxillary process and the roof of the stomodeum with laminin were slight. Sections stained with antibody to fibronectin displayed intense staining throughout the mesenchyme in both the maxillary process and the roof of the stomodeum.From comparison of the data of type IV collagen and laminin, the following hypothesis is proposed. In structures which undergo rapid change in form, such as the facial primordia, collagen distribution and/or organization is altered to a much greater extent than laminin, which is more uniformly distributed and which may be required for structural support of other developmentally regulated macromolecules. Where tissue morphology must be maintained, such as the roof of the stomodeum, the concentration and organization of type IV collagen is maintained in a manner that confers stability to these regions.
The role of the mesenchyme in mouse neural fold elevation. I. Patterns of mesenchymal cell distribution and proliferation in embryos developing in vitro
Authors: Morris‐Wiman Joyce , Brinkley Linda L. 
Published: February 2005

AbstractUsing the computer‐assisted method of smoothed spatial averaging, spatial and temporal patterns of cell distribution and mitotic activity were analyzed in the cranial mesenchyme underlying the mesencephalic neural folds of mouse embryos maintained in roller tube culture. Total cell density increased in central and medial mesenchymal regions after 12 hr in culture, decreased after 18 hr, and showed a further decrease after 2 hr when the neural folds of the embryos had elevated, converged, and were fusing or fused. Mitotic activity, as measured by the ratio of 3H‐thymidine‐labeled cells to unlabeled cells, was highest in the central mesenchyme at all culture times.Embryos were also cultured in the presence of diazo‐oxo‐norleucine (DON), which inhibits glycosaminoglycan and glycoprotein synthesis. After 24 hr in culture, neural folds of DON‐treated embryos had failed to elevate. Total cell density increased in central and medial regions of the mesenchyme of DON‐treated folds at 12 hr but showed no significant decrease in these regions with further culture. Mitotic activity was highest in the central mesenchyme of these treated embryos.These results suggest that cell distribution patterns observed in the cranial mesenchyme during neural fold elevation in normal cultured embryos are not produced by regional differences in mitotic activity. Rather, we propose that cell distribution patterns in the central and medial regions of the mesenchyme result from expansion of a glycosaminoglycan‐rich extracellular matrix that disperses cells from these regions and decreases their density. In DON‐treated embryos, in which expansion of the mesenchyme is prohibited by the decreased glycosaminoglycan and glycoprotein content of the extracellular matrix, mitotic activity apparently determines these patterns.
Neuropeptide Y localization in telencephalic and diencephalic structures of the ground squirrel brain
Authors: Reuss Stefan , Hurlbut Edward C. , Speh Joan C. , Moore Robert Y. 
Published: February 2005

AbstractThe distribution of neuropeptide Y‐immunoreactive (NPY‐IR) perikarya, fibers, and terminals was investigated in the brain of two species of hibernatory ground squirrels, Spermophilus tridecemlineatus and S. Richardsonii, by means of immunohistochemistry. In the telencephalic and diencephalic structures studied, distinct patterns of NPY‐IR were observed which were essentially identical in male and female animals of both species. No differences in amount or distribution of NPY‐IR structures were observed between animals which had been in induced hibernation for several months before sacrifice in March/April and those sacrificed one week after their capture in May. In some brain structures (e.g., the hypothalamic arcuate nucleus), IR cell bodies were observed only after pretreatment with colchicine.NPY‐IR perikarya and fibers were found in the cerebral cortex, caudate nucleus‐putamen, and dorsal part of the lateral septal nucleus. Dense fiber plexuses were seen in the lateral and medial parts of the bed nucleus of the stria terminalis. The numbers of IR perikarya observed in the medial part of the nucleus increased following intraventricular colchicine injections. The accumbens nucleus exhibited few IR cells and many fibers. Claustrum and endopiriform nuclei showed a considerable number of stained cells and fibers that increased in number and staining intensity in colchicine‐treated ground squirrels. The induseum griseum showed a small band of IR cell bodies and varicose fibers. Bipolar of multipolar IR cells and varicose fibers were found in the basal nucleus of the amygdala.Dense fiber plexuses as well as IR terminals were seen in the median, medial, and lateral preoptic areas of the hypothalamus. Terminals and relatively few fibers were located in the periventricular, paraventricular, and supraoptic nuclei. The anterior, lateral, dorsomedial, and ventromedial hypothalamic nuclei contained relatively large numbers of terminals and fibers. In the suprachiasmatic nuclei, dense terminals were distributed mainly in the ventromedial subdivision. In the median eminence, immunoreactive terminals were concentrated in the external layer, with fibers predominant in the internal layer. NPY‐IR perikarya were observed only in the arcuate nucleus of the hypothalamus and only following colchicine treatment. In the epithalamus (superficial part of the pineal gland and habenular nuclei), varicose fibers appeared mainly in perivascular locations (pineal) or as a dense plexus (habenular nuclei). These results from ground squirrels are discussed in comparison to those obtained in other species and with regard to considerations of the physiological role of NPY.
Occurrence of colloid‐containing follicles and ciliated cysts in the hypophysial pars tuberalis from guinea pigs of various ages
Authors: Kameda Yoko 
Published: February 2005

AbstractColloid‐containing follicles and ciliated cysts in the hypophysial pars tuberalis of guinea pigs at various ages ranging from 5 days to 36 months were examined by periodic acid‐Schiff (PAS) reaction, immunohistochemistry, and electron microscopy. The follicles storning PAS‐positive colloid were encountered in the pars tuberalis of all guinea pigs examined, although only a few were present in young animals. The follicles gradually increased in number with age. The largest number of follicles was found in the senile male group: 141.3 ± 11.9, about 10 times the number in the 5‐day‐old male group. The follicles were scattered throughout the entire length of the pars tuberalis. Follicles with enlarged luminal cavities were concentrated in the ventral caudal region surrounding the infundibular stem and merges with the pars distalis. Three different types of follicles were found by electron microscopy:(1) those surrounded by nongranulated follicular cells that may correspond to the stellate‐follicular cells in the pars distalis, (2) those surrounded by specific cells that were packed with vesicular inclusions, and (3) those surrounded by granulated cells that may be gonadotropes. In the follicles lined by nongranulated follicular cells, long, prominent microvilli and cytoplasmic processes protruding into the lumen and invaginations of colloid were often observed at the apical cell region. The follicles lined by the specific cells having numerous vesicles were localized only in the ventral caudal portion. The vesicles ranged from 200 to 700 nm in diameter, and the outer surface of their limiting membrane was partly studded with ribosomes. Gonadotropes immunoreactive to the luteinizing hormone (LH) and follicle‐stimulating hormone (FSH) antisera were distributed in the guinea pig pars tuberalis. As well as the typical follicles described above, the follicles composed solely of granulated cells showed microvilli protruding into the cavities and junctional complexes at the apical lateral surface. They stored heterogeneous materials in the lumina. Some secretory granules gave the appearance of being discharged into the lumen. Ciliated cysts were frequently observed in the pars tuberalis; their incidence was 71.7%. The ciliated cysts were much larger than colloid‐containing follicles. Cystic cavities were only partly filled with heterogeneous materials showing colloid‐like, flocculent, and granular features.
Localization of pigment cells in cultured frog skin
Authors: Denefle Jean‐Pierre , Lechaire Jean‐Pierre 
Published: February 2005

AbstractThe pigmentation pattern of ventral skin of the frog Rana esculenta consists mainly of melanophores and iridophores, rather than the three pigment cells (xanthophores, iridophores, and melanophores) which form typical dermal chromatophore units in dorsal skin. The present study deals with the precise localization and identification of the types of pigment cells in relation to their position in the dermal tracts of uncultured or cultured frog skins. Iridophores were observed by dark‐field microscopy; both melanophores and iridophores were observed by transmission electron microscopy.In uncultured skins, three levels were distinguished in the dermal tracts connecting the subcutaneous tissue to the upper dermis. Melanophores and iridophores were localized in the upper openings of the tracts directed towards the superficial dermis (level 1). The tracts themselves formed level 2 and contained melanophores and a few iridophores. The inner openings of the tracts made up level 3 in which mainly iridophores were present. These latter openings faced the subcutaneous tissue.In cultured skins, such pigment‐cell distribution remained unchanged, except at level 2 of the tracts, where pigment cells were statistically more numerous; among these, mosaic pigment cells were sometimes observed.
Immunocytochemical localization of growth hormone and growth hormone‐releasing hormone immunoreactivity in the brain and pituitary of the little brown bat
Authors: Anthony Edythe L. P. , Bruhn Thomas O. , Weston Paula J. 
Published: February 2005

AbstractAnterior pituitary cells exhibiting growth hormone (GH) immunoreactivity and forebrain neurons containing growth hormonereleasing hormone (GHRH) immunoreactivity were identified in little brown bats (Myotis lucifugus) using light microscopic immunocytochemistry. Pituitary somatotropes appeared as ovoid or polyhedral cells that were distributed throughout most of the pars distalis, with the exception of its most rostral region where this cell type was scarce. GH‐immunoreactive cells occupied approximately one‐third of the total volume of the pars distalis; this proportion did not differ significantly between males and females or in bats collected at different times of year. Neuronal perikarya containing immunoreactive GHRH were observed in the hypothalamic arcuate and suprachiasmatic nuclei, as well as in the cortical and subcortical telencephalon. Fibers were most evident in the median eminence, paraventricular and periventricular nuclei, and molecular layer of the cerebral cortex. Fine fibers were also accumulated in the bed nucleus of the stria terminalis and in the amygdala.
Changes in cells' secretory organelles and extracellular matrix during endochondral ossification in the mandibular condyle of the growing rat
Authors: Marchi Fausto , Luder Hans U. , Leblond Charles‐Philippe 
Published: February 2005

AbstractThe mandibular condyle from 20‐day‐old rats was examined in the electron microscope with particular attention to intracellular secretory granules and extracellular matrix. Moreover, type II collagen was localized by an immunoperoxidase method.The condyle has been divided into five layers: (1) the most superficial, articular layer, (2) polymorphic cell layer, (3) flattened cell layer, (4) upper hypertrophic, and (5) lower hypertrophic cell layers. In the articular layer, the cells seldom divide, but in the polymorphic layer and upper part of the flattened cell layer, mitosis gives rise to new cells. In these layers, cells produce two types of secretory granules, usually in distinct stacks of the Golgi apparatus: type a, cylindrical granules, in which 300‐nm‐long threads are packed in bundles which appear “lucent” after formaldehyde fixation; and type b, spherical granules loaded with short, dotted filaments. The matrix is composed of thick banded “lucent” fibrils in a loose feltwork of short, dotted filaments.The cells arising from mitosis undergo endochondral differentiation, which begins in the lower part of the flattened cell layer and is completed in the upper hypertrophic cell layer; it is followed by gradual cell degeneration in the lower hypertrophic cell layer. The cells produce two main types of secretory granules: type b as above; and type c, ovoid granules containing 300‐nm‐long threads associated with short, dotted filaments. A possibly different secretory granule, type d, dense and cigar‐shaped, is also produced. The matrix is composed of thin banded fibrils in a dense feltwork.In the matrix of the superficial layers, the “lucency” of the fibrils indicated that they were composed of collagen I, whereas the “lucency” of the cylindrical secretory granules suggested that they transported collagen I precursors to the matrix. Moreover, the use of ruthenium red indicated that the feltwork was composed of proteoglycan; the dotted filaments packed in spherical granules were similar to, and presumably the source of, the matrix feltwork. The superficial layers did not contain collagen II and were collectively referred to as perichondrium. In the deep layers, the ovoid secretory granules displayed collagen II antigenicity and were likely to transport precursors of this collagen to the matrix, where it appeared in the thin banded fibrils. That these granules also carried proteoglycan to the matrix was suggested by their content of short dotted filaments. Thus the deep layers contained collagen II and proteoglycan as in cartilage; they were collectively referred to as the hyaline cartilage region.
Light and electron microscopic observations on ciliated vacuoles and cysts in the oviductal and endocervical epithelia of the rabbit
Authors: Odor D. Louise 
Published: February 2005

AbstractCiliated vacuoles and intraepithelial cysts have been observed in oviductal and endocervical epithelia of rabbits. In this study, rabbits under various hormonal conditions were studied by light and transmission electron microscopy and tissue culture in an attempt to determine their distribution and origin. Ciliated vacuoles most frequently lay in the basal cytoplasm, below or beside the nucleus, and very close to the basal lamina. A few were apically located. Their average diameter was 8.8 by 5.1 μm. Cilia and microvilli projected into the vacuolar lumen. These vacuoles were located intracellularly as evidenced first by the degeneration of both their cilia and microvilli and the moderately dense matrix that often filled the vacuolar lumen, as observed by electron microscopy. Secondly, phase microscopy of the living endocervical epithelium allowed us to observe the beating of the cilia within the vacuoles, not on the surface of such cells. Thirdly, ruthenium red stained the surface glycocalyx of the ciliated and secretory cells, but not that of the cilia and microvilli within the vacuoles.The intraepithelial cysts were not observed in all tissue blocks. The largest numbers were found in ovariectomized animals treated for 3 and 5 days with estradiol. More were seen in the isthmus and cervix than in the fimbria and ampulla. The cysts were located most often within the epithelium along the sides of, and at the bases of, the mucosal folds. They were lined by flattened epithelium of various combinations of secretory and ciliated cells.An unusual cell type was associated with some of the cysts and ciliated vacuoles. Its cytoplasm contained aggregates of mitochondria and vesicles whose contents varied in density. Although the genesis of the ciliated vacuoles is not certain, our results indicate that they may arise from aberrant positioning of proliferating procentrioles or from a defect in targeting or transporting the centrioles to the apical plasma membrane to serve as basal bodies. Fusion of adjacent ciliated vacuoles with lumina lined by secretory cells having deep apical invaginations appeared to contribute to the formation of cysts.
Morphological innervation pattern of the developing rabbit heart
Authors: Roberts L. A. 
Published: February 2005

AbstractThe morphological innervation pattern of developing fetal and neonatal rabbit hearts was delineated histochemically by a cholinesterase/silver procedure and immunohistochemically with the monoclonal antibody HNK1, an antibody which recognizes some cells derived from neuroectoderm. Cholinesterase‐containing nerves appeared distally on the outflow tract by gestational day 15 (G15). Isolated cells with cholinesterase‐stained fine processes were present near the base of the pulmonary trunk. HNK1 antibody stained the same nerves and ganglia revealed by the cholinesterase reaction and other nerves in the rabbit heart. It was used to confirm that cells with fine neuron‐like processes were present before nerve ingrowth. The G14 heart contained many HNK1 staining cells in the right atrium, outflow, and inflow tracts; cells with fine processes were few but increased at G16. By G17, a plexus of interweaving nerves and associated cells began to form at the base of the pulmonary trunk. Fine nerves encircled the base of the aorta, and others crossed the intercaval region dorsally. At G19, nerves (1) extended downward from a rich “bulbar” plexus along the front ventricular surface, (2) grew near the epicardial surface at the base of the heart along the atrial floor and ventricular roof, (3) traversed the vena cavae and intercaval region to enter the atrial roof, and (4) crossed the coronary sinus to reach the back ventricular walls. By G23, cholinesterase‐staining nerves and ganglia in the atria and, epicardially, in the ventricles formed the general innervation pattern of the newborn and adult rabbit heart.
Fiber type composition of the human female trapezius muscle: Enzyme‐histochemical characteristics
Authors: Lindman R. , Eriksson A. , Thornell L.‐E. 
Published: February 2005

AbstractThe anatomy of the human trapezius muscle is complex, with an extensive origin and fibers running in different directions. The muscle is commonly divided into three different muscle portions according to the fiber direction: the descending, transverse, and ascending portions. In a previous study in males, the structure of the muscle differed between different portions with respect to the enzyme‐histochemical fibertype profile. The lower regions of the descending portion and the transverse and the ascending portions had a predominance of type I fibers. The type II fibers were more frequent in the upper regions of the descending portion, and the cross‐sectional fiber area in this region of the muscle was smaller. In this study, we have investigated the trapezius muscle in females and compared the results with those from males. The different portions of the female muscle had a relatively even fiber‐type composition. However, there tended to be fewer type I fibers and more type IIB fibers in the descending portion of the muscle, and the fibers of the lower regions of the descending portion were somewhat larger. The fiber‐type distribution pattern was similar to that of the male trapezius muscle, but the mean cross‐sectional area of the fibers in the female muscle was considerably smaller. Thus, our conclusion is that the trapezius muscle of females has a similar activity pattern as that of males. The significantly smaller cross‐sectional fiber area, however, may indicate a lower functional capacity which may be of importance in the development of neck and shoulder dysfunction in females.
Diffusion or autocatalysis of retinoic acid cannot explain pattern formation in the chick wing bud
Authors: Papageorgiou S. , Almirantis Y. 
Published: February 2005

AbstractWe have collected several experimental data of pattern duplications due to the ZPA transplantation or application of retinoic acid on the developing chick limb bud. We have compared these data with the predictions of models based on diffusion or autocatalysis of retinoids. It turns out that these models cannot comprehensively explain the data. More specifically, retinoic acid cannot be either diffusing from a ZPA source or participate in an autocatalytic gradient formation. © 1992 Wiley‐Liss, Inc.
Temporal differentiation and migration of substance P, serotonin, and secretin immunoreactive enteroendocrine cells in the mouse proximal small intestine
Authors: Aiken Kimberly D. , Roth Kevin A. 
Published: February 2005

AbstractPrecise spatial interrelationships exist between substance P, serotonin, and secretin containing enteroendocrine cells in the gastrointestinal tract of mice. In the proximal small intestine these products are coexpressed in various combinations in single enteroendocrine cells along the crypt to villus axis in a pattern that suggests the sequential expression of substance P, serotonin, and secretin. In this report we use bromodeoxyuridine (BrdU) and multilabeling immunohistochemistry to define the temporal and spatial interrelationships between substance P, serotonin, and secretin immunoreactive cells in the mouse proximal small intestine. Our findings demonstrate the sequential expression of substance P, serotonin, and secretin in a population of upwardly migrating enteroendocrine cells and, furthermore, identify a population of crypt associated cells coexpressing substance P and serotonin that fails to traverse this pathway. The lack of secretin immunoreactive cells in the crypts suggests that local factors present in the crypts and/or on villi regulate secretin expression. The combined use of BrdU and multilabeling immuno‐histochemistry provides a method for defining enteroendocrine cell differentiation pathways throughout the gastrointestinal tract. © 1992 Wiley‐Liss, Inc.