bluuebunny/crossref_metadata_2025 huggingface dataset:
Architectural design, fiber‐type composition, and innervation of the rat rectus abdominis muscle
Authors: Hijikata Takao , Wakisaka Hitoshi , Yohro Takeshi
Published: February 2005

The rectus abdominis muscle is architecturally compartmentalized by tendinous intersections and is supplied by multiple thoracic nerves. In this study, the rectus abdominis of the rat has been qualitatively and quantitatively examined with regard to muscle dimensions, fiber organization, fiber‐type composition, and innervation. The muscle exhibits architectural heterogeneity and different patterns of innervation among its thoracic, epigastric, and hypogastric parts. The epigastric part, adherent to the rectus sheath via tendinous intersections, represents relatively simple design. It is formed by serially arranged compartments with shorter fibers, compared with the other parts. These compartments are segmentally supplied by thoracic nerves. The hypogastric part is more complex, forms an interdigitation of muscular slips, and has segmental distribution of thoracic nerves in mediolateral direction. The thoracic part much differs from the other parts. It has smaller cross‐sectional areas, compartments composed of abundant nonspanning fibers with intrafascicular termination, and non‐segmental distribution of thoracic nerves. In addition to these craniocaudal specializations among the three parts, the muscle exhibits mediolateral differences in fiber‐type composition. Slow‐twitch oxidative fibers are more densely distributed in the medial half region than the lateral, whereas fast‐twitch glycolytic fibers follow an inverse pattern. The mediolateral differences in fiber‐type composition as well as the craniocaudal specializations in architectural design and innervation imply regionally differentiated recruitments of the muscle in various behaviors.© Willey‐Liss, Inc.
Development of the liver in the chicken embryo. I. Hepatic cords and sinusoids
Authors: Wong Gene K. , Cavey Michael J.
Published: February 2005

Hemopoiesis in the liver of the chicken embryo begins on day 7 of incubation (Hamburger and Hamilton Stage 30) and peaks on day 14 (Stage 40). During this time frame, the differentiation of hepatic cells was examined by light microscopy, transmission and scanning electron microscopy, and morphometry. The avian liver is a closely packed mass of dendriform cords and discontinuous sinusoids. Hepatocytes are pyramidal in shape, and they ring the bile canaliculi which run through the centers of the cords. Semithin sections, made possible by infiltration and embedding in glycol methacrylate, were stained with hematoxylin and eosin to assess the general architecture of the organ and the lipid content of the hepatocytes and by the periodic acid‐Schiff reaction and hematoxylin to visualize the cytoplasmic stores of glycogen. The number of hepatocytes with demonstrable glycogen fluctuates erratically in early hemopoiesis, and the proportion of glycogen‐containing cells progressively increases as hemopoiesis climbs to a peak. Most differentiating hepatocytes are devoid of lipid droplets until Stages 39 and 40. From Stage 30 to 35, hepatocyte volume falls to its lowest value. Subsequently (Stages 36 to 40), cell volume increases and hepatocytes achieve a relatively uniform size. Ultrastructural changes in the differentiating hepatocytes, including alterations to the mitochondria, endoplasmic reticulum, and Golgi apparatus, are documented. These morphological and morphometric findings on the prehepatocyte population and hepatic vasculature cover 2 of the 3 elements deemed critical to hepatic hemopoiesis in many vertebrates.© Willey‐Liss, Inc.
Quantitative morphological analysis of the pituitary gland in protein‐calorie malnourished rats
Authors: Herbert Damon C. , Yashiro Takashi , Muraki Takeshi , Okano Toshiaki , Hattori Atsuhiko , Suzuki Takuro
Published: February 2005

A quantitative analysis of the pituitary gland was conducted to ascertain the effects of protein‐calorie malnutrition on the morphology of the somatotrophs, gonadotrophs, thyrotrophs, and corticotrophs. Male rats were fed a low, 8% protein diet from 20 to 50 days of age, while their age‐matched controls were given a diet containing 27% protein. The hypophyses were then processed for light microscopic immunocytochemical staining using antibodies to growth hormone, the β subunits of luteinizing hormone and thyroid stimulating hormone, and adrenal corticotrophic hormone. The number of each cell type along with an evaluation of the cell, cytoplasmic, and nuclear areas was conducted using a computerized image analyzer. All of these parameters were reduced significantly in the somatotrophs as a result of the low protein diet, while in the gonadotrophs, the cell, cytoplasmic, and nuclear areas were similarly affected. Smaller cell number, cell area, and nuclear area were noted in the corticotrophs of the malnourished animals, while in the thyrotrophs, only the cell and nuclear areas were reduced. The data demonstrate that each pituitary cell type responds in a unique manner to undernutrition. © 1993 Wiley‐Liss, Inc.
Star volume in bone research. A histomorphometric analysis of trabecular bone structure using vertical sections
Authors: Vesterby Annie
Published: February 2005

Conventional bone histomorphometry performed on iliac crest biopsies does not generally provide unbiased stereological estimates of parameters related to bone structure due to the anisotropy of trabecular bone; this, however, can be obtained with vertical sections, which are anisotropic sections, in combination with an anisotropic test system. A practical procedure for obtaining vertical sections from bone is described. The new stereological parameter, the star volume, can provide an unbiased estimation of the absolute mean size of the marrow space and thus give an indirect estimate of the connectivity of trabecular bone structure. The marrow space star volume of vertebral bodies and iliac crest increases with age in both sexes demonstrating that the structural bone changes which occur with age is a topological one with changes in trabecular connectivity. The practical procedure including sampling efficiency for marrow space star volume is described. © 1993 Wiley‐Liss, Inc.
Observations by scanning electron microscopy of oviductal epithelial cells from cows at follicular and luteal phases
Authors: Abe Hiroyuki , Oikawa Taneaki
Published: February 2005

The luminal surfaces of epithelial cells in various regions of the bovine oviduct from cows, at the follicular and luteal phases of the estrous cycle, were examined by scanning electron microscopy. Marked cyclic changes were observed on the surface of the epithelium in the fimbriae and ampulla, but few changes were found in the isthmus and uterotubal junction. The epithelium of the fimbriae and ampulla of oviducts in the follicular phase were densely ciliated, and the cilia concealed the apical processes of the nonciliated cells. In the luteal phase, the nonciliated cells predominated in the epithelium and most of the ciliated cells were hidden by the bulbous processes of the nonciliated cells. The epithelium of the ampullar‐isthmic junction showed similar changes, but to a lesser extent. In the isthmus and at the utero‐tubal junction, the apical surfaces of the nonciliated cells were flat or gently rounded during the estrous cycle. Quantitative examinations by light microscopy showed that the mean percentage of ciliated cells significantly decreased in the fimbriae and ampulla at the luteal phase, but not in the other regions. The height of ciliated cells decreased dramatically in the fimbriae, ampulla, and ampullar‐isthmic junction at the luteal phase. By contrast, the height of nonciliated cells decreased significantly in the ampullar‐isthmic junction, isthmus, and utero‐tubal junction at the luteal phase, but not in the fimbriae and ampullae. The results demonstrate that there are regional variations and cellular differences in the cyclic changes associated with the oviductal epithelial cells in the cow. © 1993 Wiley‐Liss, Inc.
Immunolocalization of basal lamina components during development of chick otic and optic primordia
Authors: Hilfer S. Robert , Randolph Gwendalyn J.
Published: February 2005

Immunolocalization of laminin, fibronectin, and type IV collagen was examined during early morphogenetic shape changes of the avian inner ear and eye. The ear was studied from formation of the otic placode to invagination of the otic pit and the eye from the optic vesicle stage to formation of an optic cup. Distribution and intensity of immunoreactivity were compared in the two organ primordia and in adjacent epithelial layers. Laminin formed a continuous layer at the basal surface of the otic ectoderm and adjacent neural tube at all stages. The basal surfaces of the optic and lens epithelia also were continuously covered with laminin throughout development. The otic placode became attached to the neural ectoderm through a single layer of fibronectin and collagen IV between the layers of laminin. The ring‐like attachment between the edges of the optic cup and lens primordium had the same structure. In addition, the central regions of the optic and lens primordia were attached by fibrils containing type IV collagen, whereas finer strands containing fibronectin and laminin also connected the otic epithelium and neural tube. The results are discussed in terms of models of invagination for the two primordia. © 1993 Wiley‐Liss, Inc.
Renal tubule of dogfish, Scyliorhinus caniculus: A comprehensive study of structure with emphasis on intramembrane particles and immunoreactivity for H+‐K+‐adenosine triphosphatase
Authors: Hentschel H. , Mähler S. , Herter P. , Elger M.
Published: February 2005

The ultrastructure of renal tubule cells was studied in the European lesser spotted dogfish by the evaluation of thin sections and freeze fracture replicas. Computer‐assisted three‐dimensional reconstruction of entire nephrons was performed. The distinction of nephron segments and collecting tubule was made using results of previous histological work. The first proximal tubule segment (PI) consists of two subsequent portions, PIa and PIb. PIa is a component of the lateral countercurrent bundle, and PIb, which displays an apical tubulovesicular apparatus and an extended lysosomal compartment, is located in the vicinity of the glomeruli. Rod‐shaped intramembrane particles were detected in PIa. The second proximal tubule segment (PII) is a special segment in elasmobranch and teleost fish. PII differs largely from PI in cell morphology and function. The apical cytoplasm was filled with small clear vesicles, and an apical endocytic apparatus was lacking. In the apical cell membrane, rod‐shaped particles were revealed by freeze fracture. The apical tight junctions of PI and PII consisted of seven to ten meandering strands. The distal nephron was subdivided into two major segments: early distal tubule (EDT) in the lateral countercurrent bundles and late distal tubule (LDT) in the mesial tissue. The EDT showed marked amplification of basolateral cell membranes. The tight junctions displayed a low number of continuous parallel strands, which is also characteristically found in the diluting segments of other vertebrates. LDT cells showed cytoplasmic studs and rod‐shaped intramembraneous particles at the apical cell membrane, thereby resembling type A intercalated cells of collecting duct. The collecting tubule (CT) emerged from the LDT and was part of the countercurrent arrangement inside the lateral bundles. Tight junctions of LDT and CT consisted of many meandering strands in a honeycomb pattern. With immunohistochemistry, binding sites of a polyclonal antibody against an extraplasmic portion of rat gastric H+‐K+‐adenosine triphosphatase (ATPase) were observed at the apical cell membrane of PIa, PII, and LDT. From the colocalization of binding sites for the antibody against the transport enzyme with rod‐shaped intramembrane particles, we assume that these might be the morphological correlate of gastric H+‐K+‐ATPase‐like enzyme in the renal tubule. © 1993 Wiley‐Liss, Inc.
Basement membrane formation and re‐distribution of the β1 integrins in a human intestinal co‐culture system
Authors: Vachon Pierre H. , Durand Josée , Beaulieu Jean‐Francois
Published: February 2005

We have developed a co‐culture system suited for the study of epithelial‐mesenchymal interactions in the human fetal small intestine. As the epithelial component of this model, we used the human intestinal cell line Caco‐2 that is unique in its property to differentiate in vitro into a mature fetal enterocyte‐like cell type. A sheet of human intestinal mesenchymal cells, which we derived from an 18‐week‐old fetus, was used as mesenchymal element. Expression and distribution of cell‐specific markers (cytokeratin 18 and dipeptidyl peptidase IV), major basement membrane components, and β1 integrins were analyzed. In 14‐day co‐cultures, Caco‐2 cells formed a cytokeratin 18‐positive epithelial‐like sheet covering the vimentin‐positive HIM cell layers. As assessed by brush border dipeptidyl peptidase IV expression, co‐cultured Caco‐2 cells achieved cytodifferentiation as when cultured on plastic. A complete deposition of all known major human fetal intestinal basement membrane components occurred at the Caco‐2/HIM interface. Type IV collagen and tenascin were produced from the mesenchymal compartment, whereas laminin and fibronectin were contributed by both cell types. Interestingly, synthesis and deposition of basement membrane heparan sulfate proteoglycan were exclusively observed in co‐cultures, suggesting modulation of epithelial expression of this molecule by HIM cells. Finally, we observed that epithelial integrin‐β1 chains redistributed at the basal domain of co‐cultured Caco‐2 cells. Taken to gether, these observations indicate that the Caco‐2/HIM co‐culture model is a valuable system to study in vitro human basement membrane formation in the context of intestinal epithelial‐mesenchymal interactions. © 1993 Wiley‐Liss, Inc.
Monoclonal antibodies identifying subsets of ectodermal, mesodermal, and endodermal cells in gastrulating and neurulating avian embryos
Authors: Ellis Linda C. , Smith Alan M. , Alvarez Ignacio S. , Schoenwolf Gary C.
Published: February 2005

The goal of our laboratory research is to elucidate the mechanisms underlying gastrulation and neurulation, using the avian embryo as a model system. In previous studies, we used two approaches to map the morphogenetic movements involved in these processes: (1) we constructed quail/chick transplantation chimeras in which grafted quail cells could be identified within chick host embryos by the presence of nucleolarassociated heterochromatin, and (2) we microinjected exogenous cell markers. However, it would be advantageous to be able to detect endogenous markers to demarcate various subsets of cells within the unmanipulated embryo. To elucidate such a series of natural markers, we have used monoclonal antibodies to identify epitopes found on subsets of ectodermal, mesodermal, and endodermal cells. Antibodies were made by immunizing mice against either homogenized ectoderm (i. e., Prospective neural plate and surface ectoderm) or primitive streak, which had been microdissected from stage 3 chick embryos. Additionally, we screened a panel of antibodies made against soluble protein obtained from isolates of cell nuclei from late embryonic chick brain. Here, we describe the labeling patterns of three monoclonal antibodies, called MAb‐GL1, GL2, and GL3 (GL, germ layer), during avian gastrulation and neurulation. Our results show that labeling early avian embryos with monoclonal antibodies can reveal previously undetected distributions of cells bearing shared epitopes, providing new labels for subsets of cells in each of the three primary germ layers. © 1993 Wiley‐Liss, Inc.
Chronology of peroxidase activity in the developing rat parotid gland
Authors: Redman Robert S. , Field Ruth B.
Published: February 2005

The course of development of salivary peroxidase, an enzyme that has an important role in oral defense mechanisms, has been well documented in rat submandibular glands. However, the only report on salivary peroxidase activity in the other major salivary glands of the rat has been a cytochemical study of the adult parotid gland. In the present investigation, the accumulation of salivary peroxidase activity in developing parotid glands of rats was followed both biochemically and cytochemically. Specific activity (units per mg protein) attributable to salivary peroxidase began at 1 day after birth, then rose rapidly but unevenly, with peaks at 21 and 70 days, and no difference between the sexes at any age. Activity per gland increased progressively to 42 days in both sexes and was significantly higher in males at 70 days. The cytochemical observations on peroxidase activity localized to the rough endoplasmic reticulum and secretory granules of the developing acini were well correlated with the biochemical findings. Peroxidase‐negative cells occurred in immature acini at 1 and 7 days, but only in the intercalated ducts thereafter. This observation suggests that the acini are a source of some of the ductal cells, at least during early postnatal development. The developmental pattern of specific activity differed from those of other rat parotid secretory enzymes, indicating that control of their synthesis during development is noncoordinate. The patterns of specific activity of the parotid and submandibular glands were complementary, suggesting that their combined secretions may supply biologically significant peroxidase activity to the oral cavities of rats throughout postnatal development. © 1993 Wiley‐Liss, Inc.
Foveal topography in the optic nerve and primary visual centers in Falconiforms
Authors: Inzunza Oscar , Bravo Hermes
Published: February 2005

The topography of the retinal nasal and temporal foveal projections upon the optic nerve and primary visual centers was studied in diurnal bifoveate birds of prey by means of restricted tritiated proline intraocular injection.

According to the degree of retinotopy, this study reveals that a single injection of tracer in the nasal or temporal fovea produces a well‐defined and complementary pattern of projections in the following contralateral nuclei: lateral anterior thalamus, lateroventral geniculate nucleus (glv), superficial synencephalic (ss), tectal grey (gt), and optic tectum. In the thalamic nucleus dorsolateral anterior, the nasal foveal projections are seen mainly in the lateral and rostrolateral subdivision, while temproal projections are seen mainly in the magnocellular subdivision. In the external and ectomammillary nuclei there is some evidence of retinotopic innervation. Finally, a discrete field of projection from the nasal or temporal fovea is detected in lateral hypothalamus, ventrolateral thalamus, lateral geniculate intercalated nucleus, and pretectal optic area.

The nasotemporal axis of the retina is ventrodorsally oriented in the optic nerve with ganglion cell axons of the temporal fovea more dorsally placed than the nasal ones. In the primary visual centers this retinal axis is mediolaterally rpresented in the nuclei glv, ss, and gt, and dorsoventrally oriented in the optic tectum. © 1993 Wiley‐Liss, Inc.
Ultrastructure and innervation of neuroepithelial bodies in the lungs of newborn cats
Authors: Van Lommel Alfons T. L. , Lauweryns Joseph M.
Published: February 2005

Neuroepithelial bodies (NEB) occur throughout the airway mucosa and alveolar parenchyma of kitten lungs. In the bronchi, they are often situated on top of a cartilage plate. They form compact corpuscles containing 10–20 corpuscular cells and appear covered with a layer of flattened Claracells. Kitten NEB are occasionally observed to display mitosis of the corpuscular epithelial cells. A prominent blood capillary lies at their basal pole. The corpuscular cells contain numerous dense core vesicles (DCV), whose number and diameter remain unchanged with age. Kitten NEB are innervated by nerve fibres that “loop” through the corpuscle and form morphologically afferent as well as efferent nerve endings. The nerve endings display afferent synaptic junctions with the corpuscular cells and sometimes run in clusters, so that they contact each other. Many nerve endings undergo spontaneous degeneration.

We conclude that kitten NEB are well adapted to function as chemoreceptors and as endocrine or paracrine organs. Their chemoreceptor activity could be modulated by axon reflexes since their afferent nerve endings are often continuous with the efferent ones, as well as by interneural modulation since nerve endings often form clusters. In addition, kitten NEB innervation appears to involute rapidly soon after birth. This may indicate that their chemoreceptor function is only of primary importance during gestation and at birth. However, the secretory function of kitten NEB, as evidenced by the unchanged numbers and dimensions of their DCV, seems to remain steady throughout life.© 1993 Wiley‐Liss, Inc.
Chronic hyperoxia and hamster pulmonary neuroendocrine cell bombesin and calcitonin
Authors: Nylen Eric S. , Becker Kenneth L.
Published: February 2005

Hamsters were exposed to 60% hyperoxia for 1 week, 3 weeks, or 3 months. The exposed animals gradually failed to gain body weight as controls. The pulmonary neuroendocrine (PNE) cell peptides, mammalian bombesin (MB) and immunoreactive calcitonin (iCT), were determined in the lung and the serum. At 1 week and 3 weeks, lung MB was unchanged while the iCT levels were markedly depleted. In contrast, the lung levels of both MB and iCT were significantly elevated at 3 months. Serum levels of MB showed an initial decline at 1 week, which was followed by augmented levels at 3 weeks and at 3 months. In contrast, serum iCT showed considerable depletion at 1 week, and also at 3 weeks, followed by increased levels at 3 months.

Thus, chronic exposure to hyperoxia causes profound perturbation of PNE cell peptides. In particular, the early depletion of lung and serum iCT appears to be a unique feature of the response to hyperoxia. The principal difference between the MB and the iCT responses was the lack of an initial depletion of lung MB, and the earlier rise of serum MB to supranormal levels. It seems likely that the early peptide effects of hyperoxia are related to oxygen toxicity upon the PNE cells, while the changes noted at 3 months reflect a hyperplastic accommodation of PNE cells to the prolonged oxygen exposure with resultant increases in MB and iCT. This response is distinctly different from that we have seen previously in hamsters exposed to hyperoxia combined with a nitrosamine, or a nitrosamine alone. © 1993 Wiley‐Liss, Inc.
Spatial distribution of muscle fibers in a lumbrical muscle of the rat
Authors: Gates H.‐J. , Betz W. J.
Published: February 2005

The spatial distributions of two differnt populations of muscle fibers were measured in cross‐sections taken from the mid‐belly of adult 4DL muscles. Muscle fibers belonging to a single motor unit (identified by glycogen depletion) were distributed randomly in most muscles. Muscle fibers which contained slow myosin (identified immunohistochemically) were distributed nonrandomly, being evenly distributed throughout most of the muscle cross‐section, but excluded from the edge of the muscle. Interpreted from a developmental perspective, the results are consistent with the proposals that slow myosin‐containing fibers in the adult represent the original population of primary myotubes, and that the adult pattern of motor unit fiber type is achieved by synapse elimination from mismatched fibers rather than by conversion of fiber type. © 1993 Wiley‐Liss, Inc.
Prolactin alters the expression of integumental glycoconjugates in the red‐spotted newt, Notophthalmus viridescens
Authors: Singhas Charles A. , Ward Demetrice L.
Published: February 2005

Prolactin (PRL)‐mediated changes in the texture and secretory activity of the skin in adult red‐spotted newts may involve alterations in the distribution and/or expression of structural and secretory epidermal glycoconjugates. To explore this possibility, skin samples were obtained from groups of conditioned animals that had received injections of either ovine prolactin or amphibian saline over a 14‐day period. Glycoconjugates within the epidermis and cutaneous glands were examined by means of lectin hitochemistry using a panel of eight HRP‐labelled lectins. PRL increased levels of sialic acid and n‐acetylglucosamine in the stratum corneum. In contrast, glycoconjugates containing fucose, galactose, n‐acetylgalactosamine, and galactose‐(1,3)‐n‐acetylgalactosamine were decreased by PRL within both glands and epidermis. These results suggest that the intergumental effects associated with prolactin in the red‐spotted newt are mediated, at least in part, through the alteration of epidermal and glandular glycoconjugates. © 1993 Wiley‐Liss, Inc.
Stretch induces non‐uniform isomyosin expression in the quail anterior latissimus dorsi muscle
Authors: Alway Stephen E.
Published: February 2005

Stretch‐overload has been shown to elevate muscle mass in the avian anterior latissimus dorsi (ALD) by increasing both fiber size and fiber number; however, it is not known if these adaptations result in uniform regulation of myosin isoform expression along the length of the fibers in this slow tonic muscle. When a weight was added to the left wing of 20 adult quail for 30 days, ALD mass was increased by 161%. ALDs were divided into proximal, middle, and distal portions. Tissue cross‐sections from each muscle portion were reacted against monoclonal antibodies for either fast (FM) or slow myosin (SM), or processed for identification of native myosin isoforms. The number of fibers expressing FM increased by 190% in the distal region after stretch; however, most of these were small fibers. Electrophoretic analyses of stretched muscles demonstrated an upregulation of SM2 in all regions of the ALD. SM1 was only down‐regulated in the proximal region of the ALD. FM isoforms had greater increases in the proximal region than other regions of the overloaded ALD. These data indicate that stretch‐induced hypertrophy induces a non‐uniform increase in fast myosin isoforms and SM1 along the length of the fibers of the ALD. © 1993 Wiley‐Liss, Inc.
Morphometric analysis of fetal rat lung development
Authors: Moschopulos Michael , Burri Peter H.
Published: February 2005

Applying the zone concept described previously, we quantitatively analyzed fetal rat lung development. The zone concept allowed us to coherently define reference spaces in the developing lung, a prerequisite for morphometric analysis.

The peripheral zone I corresponds to a zone of growth of yet undifferentiated tissues; zone II arises from zone I and represents a region of structural and cellular differentiation; zones III and IV comprise the conducting airways and vessels.

Lungs of fetal rats aged 17–23 days and 20 hours postnatal were fixed with OsO4 and glutaraldehyde and processed for light and electron microscopic morphometry implemented by point and intersection counting.

Fetal lung volume grew in proportion to body weight. Zone II being the largest compartment, its volume changes largely determined lung growth rates. Zone II increased in mass owing to differentiation processes at the interface to zone I where the proximal portions of zone I were continuously shifted into zone II by differentiation. New tissue was generated within zone I. Due to these combined processes zone I changed little in volume until it disappeared at the end of the canalicular stage. The presence in the pseudoglandular stage of half of the parenchymal epithelial mass available around birth indicated that parenchymal development started earlier than assumed so far.

While the endothelial surface increased most at birth, the epithelial surface grew by more than 600% at day 21, reflecting the onset of canalisation.

The study confirmed the usefulness of the zone concept for morphometry and provided some new insights into lung development. © 1993 Wiley‐Liss, Inc.
Acetylcholinesterase activity is associated with efferent endings in the sensory epithelia of the utricle and semicircular canals of the rainbow trout inner ear
Authors: Khan Khalid M. , Drescher Marian J. , Hatfield James S. , Drescher Dennis G.
Published: February 2005

The mechanosensory hair cells of the utricle and semicircular canals of the trout inner ear are morphologically similar to type II hair cells of the avain and mammalian vestibular end organs. These cells are innervated by two types of nerve terminals. The nonvesiculated terminals are considered to be afferent, and the vesiculated endings are presumed to be efferent. The presumptive efferent endings contain numerous clear, round vesicles and a few that are dense‐cored. Histocytochemical, electron microscopic analysis has localized acetylcholinesterase activity to plasma membranes of vesiculated, presumptive efferent nerve terminals in sensory epithelia of the utricle and semicircular canals. No reaction product was observed at the receptoneural synapse or found in nonvesiculated, presumptive afferent endings. Control specimens incubated in the presence of eserine sulfate, an inhibitor of acetylcholinesterase, were devoid of reaction product. These results support the tenet that vesiculated nerve endings in the sensory epithelia of the utricle and semicircular canals of the trout are cholinergic. © 1993 Wiley‐Liss, Inc.
Ribosomes in the skeletal muscle filament lattice
Authors: Gauthier Geraldine F. , Mason‐Savas April
Published: February 2005

The compartmentalization of myosin isoforms within a muscle cell (Gauthier: J. Cell Biol. 110:693–701, 1990) suggests that myosin might be assembled directly into thick filaments at sites where it is synthesized. We therefore examined myofibrils by immunoelectron microscopy to determine whether ribosomes are associated with thick filaments under conditions in which new myosin can be identified. We used the embryonic chick anterior latissimus dorsi (ALD), a slow muscle that is induced, by curare, to synthesize a fast myosin isoform that is not normally present. Myosin was localized in situ, using a gold‐labeled monoclonal antibody that recognizes the new isoform. The gold marker, as expected, was localized preferentially to the A band. There was an overall increase of fivefold in the number of gold particles per μm2 of A band in the curare‐treated compared to the normal ALD, indicating that the labeled isoform was largely newly formed. There was a corresponding preferential distribution of ribosomes at the A band, especially in the H‐band region, and the number of ribosomes per μm2 of A band was nearly twice as high in the curare‐treated as in the normal muscle. Ribosomes were located between thick filaments, often aligned in rows. We conclude that ribosomes are located within the filament lattice, and therefore that they are available for local myosin synthesis. © 1993 Wiley‐Liss Inc.
Sertoli cell cycle: A re‐examination of the structural changes during the cycle of the seminiferous epithelium of the rat
Authors: Ye Shi‐Jun , Ying Li , Ghosh Sushmita , De França Luiz Renato , Russell Lonnie D.
Published: February 2005

Seminiferous tubules in mammals are composed of cell associations that show a cyclic pattern of renewal and development. The cyclic nature of germ cell development suggests that the cells supporting the spermatogenic process, the Sertoli cells, might also differ structurally during the spermatogenic cycle in terms of the quantity of their constituents. In the present study, cyclic differences in volumes, and surface areas were determined using a sampling technique at the electron microscope level that proportionally samples the Sertoli cell within the seminiferous tubule. Among the many parameters studied, only the surface area of the cell, the volume of lipid, and the volume and surface area of the rough endoplasm reticulum were shown by statistical analysis to vary cyclically. Regarding rough endoplasm reticulum, the volume and surface area of this organelle peaked at mid‐cycle and its low was recorded near the end of the cycle, exhibiting an approximate 15‐fold difference between extremes. The rough endoplasm reticulum parameters generally correlated with known patterns of protein secretion within the tubule and with the secretion of specific proteins as well as the factors important in controlling protein secretion. Many Sertoli cell structural parameters suggested to be influenced cyclically in the rat in other studies could not be confirmed by the present study. Methodological differences in the present study and past studies are discussed as potential sources of error for these discrepancies. © 1993 Wiley‐Liss Inc.
Ultra‐high‐resolution scanning electron microscopic studies on the membrane system of the parietal cells of the rat in the resting state and shortly after stimulation
Authors: Ogata Takuro , Yamasaki Yuichi
Published: February 2005

The three‐dimensional organization of the membrane system of the rat parietal cells in the resting state and during early stimulation with tetragastrin (gastrin) was determined by ultra‐high‐resolution scanning electron microscopy. Specimens were prepared by cytoplasmic matrix removal using the aldehyde‐osmium‐DMSO‐osmium procedure. The intracellular canaliculus was lined with numerous microvilli. Viewed from the cytoplasmic side, the intracellular canaliculi appeared as an arborized system of cactus‐like structures with numerous round holes about 100 nm in diameter corresponding to the basal openings of the microvilli. The intracellular canaliculi were more developed after gastrin stimulation than in the resting state. In resting cells, most of the tubulovesicles were isolated, 100–200 nm in diameter, spherical or tubular in shape, and had a smooth surface. After gastrin stimulation, these structures were interconnected by slender tubules of about 30 nm in diameter forming together tubulovesicular network. Occasionally, swollen and shrunken profiles were observed. The tubulovesicular network was connected with the intracellular canaliculus only at a few sites by the slender connecting tubules. Fusion of the tubulovesicular network with the intracellular canaliculus is observed at such sites. In the fasted rat, the microvilli were slender and their interior was packed with some kind of ill‐defined material, probably microfilaments. However, after gastrin stimulation, the microvilli were swollen and their interior was almost empty. These morphological changes seem to indicate the accumulation of fluid in the microvilli after gastrin stimulation, with subsequent swelling. © 1993 Wiley‐Liss Inc.
Endothelin‐1 localization in bone cells and vascular endothelial cells in rat bone marrow
Authors: Sasaki Takahisa , Hong Mei‐Hua
Published: February 2005

Endothelin‐1 (ET‐1) localization in bone cells and associated vascular endothelial cells in metaphyseal bone marrow of the rat femur was examined by a biotin‐streptoavidin‐horseradish peroxidase method in paraffin sections and by indirect immunogold techniques in post‐embedded ultrathin sections. Mouse anti‐ET‐1 monoclonal antibody was used as the primary antibody. In metaphyseal bone marrow, intense immunostaining was observed over osteoclasts, osteoblasts, young osteocytes, and vascular endothelial cells. But bone and cartilage matrices and chondrocytes in the proliferating zone were negative for immunoreaction. At the subcellular level, specific immunogold labeling was localized along plasma membranes and in the cytoplasm including those of ruffled borders and clear zones of osteoclasts. Some colloidal gold particles were also detectable within pale vacuoles of osteoclasts. Immunoreactivity was also found along the plasma membranes, cisterns of rough‐surfaced endoplasmic reticulum, mitochondria, and cytoplasmic matrices of osteoblasts, but was less intense than that of osteoclasts. In endothelial cells of blood capillaries in close proximity to bone cells, intense immunolabeling occurred over the cytoplasm. None of the cases examined showed accumulation of immunogold particles in the secretion granules of these cells. © 1993 Wiley‐Liss, Inc.
Three‐dimensional cytoarchitecture of complex branched fibers in soleus muscle from mdx mutant mice
Authors: Tamaki Tetsuro , Sekine Tadashi , Akatsuka Akira , Uchiyama Shuichi , Nakano Shoichi
Published: February 2005

Three‐dimensional cytoarchitecture and types and features of muscle fibers were examined in soleus muscles from mdx mutant mice at different stages of development. In the 2‐week‐old mice, no abnormal muscle fibers were observed light microscopically, whereas in the 4‐week‐old animals, disrupted fibers were frequent in light microscopy and scanning electron microscopy. Muscle fibers fused with several short fiber branches appeared at the sixth week after birth and increased in number until the tenth week. In the 1‐year‐old mice, approximately ten or more muscle fibers were seen fused together. They had many complex branches forming an “anastomosing syncytial reticulum.” Muscle fibers with irregular diameters and aggregations of the same type fibers were also observed.

Our results demonstrated that these complex branched fibers might be formed by long term repetition of the degeneration and regeneration cycle during the development of soleus muscles, indicating that the characteristic features of muscle fibers with irregular diameters and aggregations of the same type fibers are certainly dependent on the existence of the complex branched fibers. © 1993 Wiley‐Liss, Inc.
Computer analysis of the human embryo growth curve: Differences between published ultrasound findings on living embryos in utero and data on fixed specimens
Authors: Dickey Richard P. , Gasser Raymond F.
Published: February 2005

Accurate information on the normal growth rate of the human embryo is fundamental to a better understanding of the embryonic period of pregnancy. Crown‐rump length measured previously in utero (N = 227) with vaginal ultrasound in 107 in vitro fertilization (IVF) or gamete intrafallopian transfer (GIFT) singleton pregnancies was compared to the greatest length of fixed human embryos from the Carnegie collection, of known developmental stage whose postovulatory ages were estimated from menstrual histories. Average crown‐rump length in utero was 60% of the greatest length of the fixed specimens prior to postovulation day 33, but were equal after postovulation day 40. The growth rate of in utero embryos and fixed specimens, analyzed by computer using exponential equations, was compared to linear and polynomial equations used in previously published embryo growth tables. The exponential equation, length = exp(a + b/age), fit in utero measurements best, while the equation length = exp[a + b/exp(age)] fit the fixed specimens best. Differences between length in utero and in fixed specimens may be related to distortion of the fixed embryos resulting from the formalin fixation, to ultrasound distortion, to curling of the embryo, or to incorrectly estimated ages of the fixed specimens. Study of human embryos in utero is now practical with vaginal ultrasound. © 1993 Wiley‐Liss, Inc.
Role for differential cell proliferation in perforation and rupture of chick pharyngeal closing plates
Authors: Miller Sue Ann , Favale Alicia M. , Knohl Stephen J.
Published: February 2005

Patterns of cell proliferation show two distinct domains around avian pharyngeal closing plates as they form, perforate, and rupture. Pouch endoderm and groove ectoderm are in one domain showing 81–86% proliferation, which suggests relatively rapid growth. Cells in epithelia that comprise the pharyngeal closing plates contiguous with pouch and groove epithelia are vital but are dividing at a significantly lower percentage (62–64%). This phenomenon is similar to the lag in growth reported for cells in the oral membrane around the time of rupture (Miller and Olcott, 1989: Anat. Rec., 223:204–208), is consistent with Waterman's suggestion (1985: Anat. Rec., 211:450–457) that cellular reorganization, rather than massive degeneration, is a major mechanism of initial perforation, and suggests that differential growth is a contributor to perforation and rupture of chick pharyngeal closing plates. © 1993 Wiley‐Liss, Inc.
Effect of soft diet and aging on rat masseter muscle and its motoneuron
Authors: Miyata Hirofumi , Sugiura Takao , Kawai Yosuke , Shigenaga Yoshio
Published: February 2005

To determine the effect of a soft diet and aging on the masticatory motor unit, we investigated the morphologic and metabolic properties of the superficial masseter muscle and its motoneurons in rats. Twenty rats were divided into four groups of five rats: rats fed a hard diet until 4 months after birth (hard, young), rats fed a soft diet until 4 months after birth (soft, young), rats fed a hard diet until 22 months after birth (hard, old), and rats fed a soft diet until 22 months after birth (soft, old). The diameter of the fast‐twitch oxidative glycolytic muscle fiber was significantly smaller in the soft than the hard, and in the old than the young groups. The glycolytic enzyme (phosphofructokinase) activity of the muscle was significantly weaker in the old than the young group. There was no significant difference in soma diameter of the motoneurons between the soft and hard group, while the diameter was significantly larger in the old than in the young group. There was no significant difference in NADH‐diaphorase activity of the motoneurons between the soft and hard group, while significantly less activity was demonstrated in the old than in the young group. The reduction in motor unit activity caused by the soft diet is considered to influence the morphologic and metabolic properties in the superficial masseter muscle but not in its motoneurons. The reduction in the oxidative enzyme activity of motoneurons with aging may occur regardless of the reduction in motor unit activity. © 1993 Wiley‐Liss, Inc.
Three‐dimensional reconstructions of the primary palate region in normal human embryos
Authors: Rudé Frank P. , Anderson Leigh , Conley David , Gasser Raymond F.
Published: February 2005

Our knowledge of the precise spatial relationships of human primary palate morphogenesis remains poorly defined. This is due to intrinsic difficulties that exist in the study of the subject matter and a lack of adequate methodologies. We present a novel new method to allow precise three‐dimensional (3‐D) visualization of developing embryonic structures in previously sectioned embryos. In our study we focus on human primary palate development. Five normal human embryos from the Carnegie collection were used. 3‐D reconstructions appear similar to scanning electron micrographs (SEM); however, unlike in SEM studies, the original specimen has been previously sectioned histologically. 3‐D reconstruction from serial sections involved (1) histological preparation of specimen, 2) projection onto digitizing board, 3) digitization, 4) automated reassembly, and 5) relay to interactive optical disc recorder. Detailed observations of each reconstruction were then made. Data generated in this manner may also be used in the near future for quantitative morphometrics. Thus, 3‐D reconstruction techniques presented in this paper generated precise spatial information on the development of the human primary palate. © 1994 Wiley‐Liss, Inc.
Plasticity of innervation of the medulla of axillary lymph nodes in the rat after antigenic stimulation
Authors: Novotny G. E. K. , Heuer T. , Schöttelndreier A. , Fleisgarten C.
Published: February 2005

The purpose of this investigation was to test the hypothesis that activation of the immune system in rats will lead to changes in the density of innervation in lymph nodes. In order to reduce the variability between animals, the rats were reared under sterile conditions and immunostimulation was effected by subcutaneous application of bovine albumin in a region draining to the axillary lymph nodes of both sides. Control animals received an equivalent application of sterile physiological saline. The animals were sacrificed 10 days and 27 days and 4 months after immunostimulation. The nerves in the axillary lymph nodes were quantified by light microscopy in silver impregnated sections and at the ultrastructural level on ultrathin sections. The survival times were chosen so that the first group was in the ascending phase of antibody production, the second group at the peak, and the third group in the declining phase. Both at the light and ultrastructural levels, there were statistically significant differences in the density of innervation of medulla between the groups, with a particularly pronounced increase in the group 4 months after immunostimulation. At the ultrastructural level, there was also an increase in the density of incompletely ensheathed axonal profiles in the parenchyma of the medulla, while the nerves associated with blood vessels were not increased. We conclude that immunostimulation leads to morphological changes in the innervation of the medulla of axillary lymph nodes, that are consistent with the concept of functional activation of the autonomic nervous system through the immune system. © 1994 Wiley‐Liss, Inc.
Effects of peripheral axotomy on presynaptic axon terminals with GABA‐like immunoreactivity
Authors: Vaughan Deborah Whittaker
Published: February 2005

The facial nerve was unilaterally crushed at its exit from the stylomastoid foramen in three 3‐month old male rats. After 10 days survival, before the regenerating axons had reinnervated their target muscles, the facial nucleus was examined to determine central patterns of response in material prepared to demonstrate the presence of GABA‐like immunoreactivity with postembedding procedures using gold‐labeled secondary antibody. The uninjured nucleus served as a control. In both control and injured nuclei, the GABAergic terminals synapse with all parts of the motor neurons, except the axon, and exhibit diverse morphologies. GABAergic axon terminals vary in their size and in the electron density of their axoplasm and the majority of the terminals contain pleomorphic vesicle profiles that display a range in their packing density and size. In both control and injured facial nuclei, only ∼40% of the axon terminal profiles with pleomorphic vesicles exhibit GABA immunoreactivity. A morphometric analysis of the synaptic vesicle profiles in the GABA‐positive terminals reveals that following axotomy there is no change in the mean number of synaptic vesicle profiles per GABAergic terminal profile. However, the mean size of the synaptic vesicle profiles in these terminals shows an axotomy‐induced 50% increase, without change in the shapes of the enlarged vesicle profiles. Also, the numerical density of gold particles associated with the GABA‐positive terminals is consistently greater in the injured than the control axon terminals. In the control animals quantitative analysis of the relative distribution of all axon terminal profiles in the neuropil categorized by the shape of their vesicle profiles as round, pleomorphic, or flat is 57:37:6. Ten days after axotomy the ratio of these categories in the injured nucleus has shifted to 35:60:5. This study demonstrates that the functional state of a postsynaptic target can influence the morphology of vesicle profiles in presynaptic elements as well as patterns of its afferent input. © 1994 Wiley‐Liss, Inc.