bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concanavalin a binding to the epithelial surface of the developing mouse olfactory placode
Authors: Smuts Marybeth S. 
Published: February 2005

AbstractConcanavalin A (Con A), a lectin binding to mannosyl and glucosyl residues of glycoproteins and glycolipids, was used to study the appearance of carbohydrate‐rich cell surface material on the olfactory placode and nasal processes which contribute to formation of the primary palate. In vivo incorporation of 3H‐thymidine was also used in an attempt to correlate changes in labeling index with formation of the olfactory placode and nasal processes.The cell surface of the early frontonasal epithelium binds Con A very little, if at all, but Con A binding was observed when the olfactory placode could be identified as a plate of cuboidal cells that exhibited a reduced labeling index. During the period of formation of the nasal processes, Con A binding was observed on the facial epithelium including the presumptive contact region. There was also a decline in the labeling index throughout primary palate formation.This study provides three criteria by which the olfactory placode can be identified: a morphological change of placode cells to a cuboidal shape, a synthesis or rearrangement of surface coat material that binds Con A, and a reduced labeling index.
The ultrastructural histochemistry of the basement membranes of the exocrine pancreas
Authors: Katsuyama T. , Poon K‐c , Spicer S. S. 
Published: February 2005

AbstractThe basement membranes in the exocrine pancreas were examined by routine electron microscopy, by fixation for electron microscopy with a glutaraldehyde‐tannic acid solution and by staining for ultrastructural demonstration of mucosubstances with the dialyzed iron, high iron diamine, ruthenium red and Concanavalin A‐horseradish peroxidase procedures. The basement membranes are considered from morphologic and histochemical observations to consist of an inner lamina lucida, an intermediate lamina densa and an outer lamina diffusa. Sulfated mucosubstance was found in the lamina diffusa of the basement membrane of all epithelial cells and capillary endothelial cells but was encountered in the lamina lucida of the duct cells exclusively. Bridging structures, presumably polypeptides, were also seen connecting the lamina densa and the basal plasma membrane in specimens fixed with the glutaraldehyde‐tannic acid solution. The findings demonstrated that the histochemical and morphological qualities of the basement membrane are uniform for a given cell type but differ considerably among the several cell types in the pancreas.
Fine structure of an end organ in the periodontal ligament of the mouse incisor
Authors: Everts V. , Beertsen W. , van den Hooff A. 
Published: February 2005

AbstractNerve endings were observed between collagen fiber bundles in the alveolar compartment of the periodontal ligament. In close relation to these endings, cells were observed with a rounded cell body from which cytoplasmic extensions protruded, each forming part of a sheath around the terminal region of a small nerve fiber. The nuclei of these cells occupied an eccentric position in the cytoplasm and were characterized by a typical kidney shape. In the cell's center a prominent Golgi complex was present. In the peripheral cytoplasm ladder‐like structures with a periodicity of 160 nm were occasionally observed. The cell bodies were surrounded by a basal lamina, while the cytoplasmic extensions investing the nerve endings were surrounded by an envelope consisting of alternating electron dense and electron translucent layers containing material that stained with PAS and Alcian Blue. Where these envelopes bordered on the connective tissue, areas of filamentous material with a periodicity of 100–150 nm were occasionally found. The end organs may be considered to form part of a receptor system.
Regional specialization of the hair cell plasmalemma in the organ of corti
Authors: Gulley R. L. , Reese T. S. 
Published: February 2005

AbstractNonjunctional and nonsynaptic membranes of hair cells in the chinchilla organ of Corti were examined using the freeze‐fracture technique. Cy‐toplasmic leaflets of the apical membranes of hair cells have particles, 6–12 nm in diameter, but many more particles are found on apical membranes of outer hair cells than on inner hair cells. Cytoplasmic leaflets of the lateral membranes of outer hair cells are covered with large particles, but the corresponding regions of the inner hair cell membrane have fewer particles and these are small or medium‐sized. Two types of particle aggregate also distinguish this region of the inner hair cell. The first consists of patches of particles closely spaced in rec tilinear arrays. The second consists of parallel strands of widely spaced large particles similar in size, but not in distribution, to the large particles on the lateral membranes of the outer hair cells. The basal membrane of outer hair cells is distinguished from that of inner hair cells by plaques consisting of cross‐hatched in‐cisures in the external membrane leaflet. While the significance of these anatomical features is not yet apparent, they give the hair cell plasmalemma a richness of regional specialization found in few other cells and suggest that there are important functional differences between inner and outer hair cells.
Differentiation of olfactory receptor cells in organ culture
Authors: Farbman Albert I. 
Published: February 2005

AbstractPresumptive olfactory mucosa was excised from the heads of rat fetuses in the eleventh and twelfth days of gestation and explanted in organ cultures. At the time of explantation, the presumptive olfactory cells were recognizable by their long narrow apical processes and basally located nuclei. However at this stage they were in an early phase of differentiation as indicated by the large numbers of free ribosomes and virtual absence of microtubules and cilia in the apical cytoplasm. After three to eight days in culture, there was a progressive increase in the total number of cells in the epithelium. Differentiation in olfactory receptor cells was detectable by the appearance in the apical processes of axially oriented microtubules and centrioles or basal bodies. Some of which generated cilia. At their basal ends, the cytoplasm narrowed into axons and bundles of these axons, arranged in the unique manner of olfactory nerve axons, entered the connective tissue. Olfactory receptor cells, as defined by morphological criteria, differentiated under suitable organ culture conditions in the absence of any tissue from the central nervous system.
Ultrastructural observations on cytoplasmic lamellar inclusions in oocytes of the rodent, Thomomys
Authors: King Barry F. , Tibbitts F. Donald 
Published: February 2005

AbstractThe object of the present study was to examine ovarian oocytes of the sciuromorph rodent. Thomomys townsendii, to determine if they contained cytoplasmic inclusions similar to those reported in myomorph rodents. Our observations indicated the presence of cytoplasmic lamellar inclusions of oocytes of primary, secondary and large vesicular follicles of Thomomys. Small primary oocytes contained numerous cytoplasmic lamellae which appeared as spirals or concentric rings in cross‐section. Longitudinal sections suggested the inclusions were arranged as concentric cylindrical sheets of material. Secondary and vesicular oocytes had morphologically similar inclusions, but, in addition, often had a tubular element of the endoplasmic reticulum associated with the core of the lamellae. Tangential sections through the lamellae revealed a crystalline substructure, regardless of the age of the oocyte. Our results indicate that cytoplasmic lamellar inclusions are not restricted to myomorph rodents, but may well be present in other species. The lamellar inclusions are three‐dimensionally most similar in structure to those described in the hamster, but several fine structural differences exist even between these species. Thomomys is the only species to date in which a close topographical association develops between the lamellar inclusions and elements of the endoplasmic reticulum. Since the lamellae‐endoplasmic reticulum association was not observed in the youngest oocytes examined, it is unlikely the endoplasmic reticulum is involved in synthesis of the lamellae, but it may, nonetheless, be metabolically related to the lamellae.
The dorsal motor nucleus of the vagus nerve of the cat: Localization of preganglionic neurons by quantitative histological methods
Authors: Smolen Arnold J. , Truex Raymond C. 
Published: February 2005

AbstractThe dorsal motor nucleus of the vagus nerve (DMX) of adult cats and young kittens was studied by quantitative light microscopic methods. In normal animals, the DMX was found to contain no distinct subgroupings of neurons, based on somatic volume or Nissl pattern. Retrograde perikaryal responses to axotomy of neurons in the DMX were found to be of a more subtle nature than those seen in other types of neurons. Quantitative methodology applied to the DMX after cervical vagotomy permitted a better understanding of the results of axotomy than could be obtained by routine microscopic observations. Changes which occurred included a slight chromatolytic reaction, and a decrease in the volume of the nucleus followed by an increase in somatic volume. These morphological alterations were affected by the factors of age of the animal, time after axotomy, and length of the intact proximal axon stump. More pronounced perikaryal changes occurred when the vagus nerve was recut at a more proximal level five days after the first vagotomy. Interpretation of the data yielded the conclusion that most if not all neurons of the ipsilateral DMX contribute axons to the cervical vagus nerge. In addition, at least 10% of the neurons on the side contralateral to vagotomy showed signs of retrograde reaction. It was therefore concluded that there exists in the vagus nerve a population of axons with cell bodies located in the contralateral DMX.
Autoradiographic demonstration of the pattern of 3H‐estradiol concentrating cells in the brain of a carnivore, the mink, Mustela vison
Authors: Morrell J. I. , Ballin A. , Pfaff D. W. 
Published: February 2005

AbstractThe purpose of this study was to examine the neuroanatomical pattern of cells which concentrate 3H‐estradiol in the brain and pituitary of a carnivore, the mink, Mustela vison. In addition, since the mink has one breeding season a year it was possible to compare the pattern and number of estradiol concentrating cells in the brains of estrous versus anestrous animals. Five female mink (three estrous; two anestrous) were ovariectomized, and one week later administered 3H‐estradiol. The animals were sacrificed, and autoradiograms were prepared with the method for steroid autoradiography used routinely in this laboratory (Pfaff and Keiner, '73). The entire brain was sampled and subsequently analyzed with the aid of a light microscope.The majority of estradiol concentrating cells were found in the hypothalamus and limbic system, although a small number were seen in other structures. Specifically, structures containing a large number of estradiol concentrating cells were: the ventral lateral septum, the bed nucleus of the stria terminalis, the medial preoptic area, medial anterior hypothalamus, the ventromedial and arcuate nuclei of the hypothalamus, the medial and cortical nuclei of the amygdala, and the anterior pituitary. Structures containing a small number of estradiol concentrating cells were also seen in the telencephalon and diencephalon. The most posterior population of estradiol concentrating cells was in the central grey of the mesencephalon. No difference in the neuroanatomical pattern or number of estradiol concentrating cells was seen when the autoradiograms from estrous animals were compared to those from anestrous animals.
Ultrastructural study of the nerve plexus accompanying the ovarian artery and vein in the rat
Authors: Payer Andrew F. 
Published: February 2005

AbstractThe ultrastructural characteristics of the nerve plexus that accompanies the ovarian vessels of the rat were studied. The nerve fibers were primarily unmyelinated with less than 5% myelinated. Two types of neuronal cell bodies were found along these nerves. They were located at variable distances along the nerve bundle. The first and more numerous was a larger cell type similar to the autonomic postganglionic neuron. The second and smaller cell type had granulated vesicles throughout the cytoplasm. Synapses of the axodendritic type and synapses between the neuronal cell bodies were found. Most of the synapses possessed agranular vesicles. The presence of neuronal cell bodies is an important characteristic to consider in evaluating denervation of the ovary by interruption of this nerve plexus.
Immunocytochemical and histochemical studies on intestinal epithelial cells producing both lysozyme and mucosubstance
Authors: Montero Claudio , Erlandsen Stanley L. 
Published: February 2005

AbstractThe simultaneous demonstration of lysozyme using the unlabelled antibody enzyme method and mucosubstances by staining with the periodic acid‐Schiff (PAS) and Alcian Blue pH 2.5 techniques has led to the identification of a new subpopulation of mucus‐producing cells containing lysozyme in small intestinal specimens from normal rats and from patients with inflammatory bowel diseases. These cells, containing both mucosubstances and lysozyme, are located in the lateral walls of the crypts of Lieberkuhn, but can occasionally be found also in or near the tips of the villi. The specific staining for lysozyme was observed in the apical and/or basal cytoplasm of these mucus‐producing cells and was readily detected in sections counterstained for mucosub‐stances with Alcian Blue. The localization of these mucus‐producing cells was similar both in the normal rat and in the pathological human specimens. Absorption controls and controls where a non‐immune serum was substituted for the specific antilysozyme serum confirmed the specificity of the lysozyme localization.
Fenestrae in the rough endoplasmic reticulum of Xenopus laevis hepatocytes
Authors: Brown Dennis 
Published: February 2005

AbstractThe rough endoplasmic reticulum (RER) of Xenopus laevis hepatocytes was examined by freeze‐fracture and by conventional thin section electron microscopy. Much of the RER was present as stacks of cisternae at the cell periphery but, in addition, large whorls of cisternae were seen in the cytoplasm in most sections. Freeze‐fracture replicas revealed fenestrae in both stacked and whorled cisternae, although the fenestrae were more numerous in the whorls. The role of these fenestrae is unknown, but such structures would facilitate access of precursors to the protein synthetic machinery in this highly metabolically active cell type. This would be particularly important in RER whorls, where the innermost cisternae would otherwise be isolated from the rest of the cytoplasm.
Arteriovenous anastomoses in the skin of seals. I. The Weddell seal Leptonychotes weddelli and the elephant seal Mirounga leonina (Pinnipedia: Phocidae)
Authors: Molyneux G. S. , Bryden M. M. 
Published: February 2005

AbstractThe structure, distribution, density and innervation of arteri‐ovenous anastomoses (AVAs) have been compared in the skin of Weddell and elephant seals, as part of a study of the structure and function of arteriovenous anastomoses in mammals.In both genera AVAs were coiled vessels with the segmental structure typical of “epithelioid” anastomoses and possessed a dense peripheral adrenergic innervation.In both Weddell and elephant seals there was no statistically significant difference between the mean density of AVAs in body skin and flipper skin. The majority, approximately 71% of AVAs occurred superficially in the dermis, fewer (23%) occurred in the deeper dermis, and 6% were present in the thick hypodermis (blubber). The density of AVAs in Weddell and elephant seals is approximately eight times greater than that reported in other animals and the superficial position of anastomoses over the whole of the body surface is characteristic of phocid seals.When open, AVAs in Weddell and elephant seals allow maximal heat loss from the skin surface by passing large volumes of blood into the superficial veins. AVAs in seals are important in dissipation of body heat, particularly when the animals are out of the water, and the entire surface area is thermo‐regulatory rather than specific regions such as the flippers.
Spermiogenesis in Nautilus pompilius. II. Sertoli cell‐spermatid junctional complexes
Authors: Arnold John M. 
Published: February 2005

AbstractA “ball and socket‐like” junction between branches of the Sertoli cells and the developing spermatids is described. A cytoplasmic extension of the Sertoli cell fits into a pocket in the spermatid and has a constricted neck region. Frequently there are large multivesiculate bodies in the Sertoli cell extension and small vesicles frequently appear in the spermatid cytoplasm, in the area of the “ball and socket‐like” junction. This suggests the possibility that there may be communication of materials between the two cells. The possible function of the junctions is discussed and it is concluded that they more likely have a role in nutrition than in coordination.
Pelvic and perineal anatomy of the male Gorilla: Selected observations
Authors: Oelrich Thomas M. 
Published: February 2005

AbstractThe anatomy of parts of the pelvic outlet and perineum is described in an adult male gorilla. Two previously undescribed muscles are presented: (1) The puborectalis muscle, completely separated from the levator ani, arises from the region of the symphysis and forms a sling for the rectum while it also substitutes for the perineal membrane. (2) The puboampullaris muscle, a paired smooth muscle, arises from the pubis and inserts into the rectum to elevate the rectum while additionally providing support for the urogenital viscera. The levator ani muscle is recounted to point out its lack of attachment to the pelvic viscera while allowing a hiatus in which the rectum is exposed within the perineum. The sphincter urethrae muscle is presented emphasizing its true sphincteric characteristics, its absence of lateral attachments and its similarity to man. Other muscles of the pelvis and perineum as well as urogenital viscera are described or modified where necessary. The manner in which these structures enter into the support of the pelvic viscera is considered.
Development of the embryonic chick otic placode. II. Electron microscopic analysis
Authors: Meier Stephen 
Published: February 2005

AbstractThe otic placode takes its origin from surface ectoderm. Prior to the arrival of neural crest cells, surface epithelial cells adjacent to the neural folds are squamous in shape and synthesize primarily interstitial bodies. However, by 26 hours of development, neural crest cells, using the undersurface of the epithelium as a substratum, migrate away from the neural tube. Cells of surface epithelium above the neural crest cells assume a columnar shape, and the amount of intercellular space between adjacent epithelial cells is consequently reduced. Placode cells show extensive interdigitation apically as they pseudostratify and invaginate, while it appears that many of the basal cells contribute components to the underlying extracellular matrix. This extracellular matrix interface between surface epithelium and neural crest cells is distinctly fibrillar and less granular than that found between ordinary head ectoderm and primary mesenchymal cells. Just prior to complete invagination as an otocyst, otic placode cells in a region near the ventrolateral wall of the hindbrain extend cell processes through discontinuities in the basal lamina and leave the otocyst. These are likely to be the cells which contribute to the formation of the acoustico‐facialis ganglion. These observations support the hypothesis that the development of the otic placode is the result of a tissue interaction between surface epithelium and neural crest cells.
A morphological study of early cellular changes in the closure of the rabbit ductus arteriosus
Authors: Yoder Monroe J. , Baumann F. Gregory , Grover‐Johnson N. M. , Brick Irving , Imparato Anthony M. 
Published: February 2005

AbstractA light and transmission electron microscopic study was performed on 67 ductus arteriosus (DA) specimens from rabbits (31 days normal gestation period) ranging in age from 21 days of gestation to 4 days after birth. Some fetuses were permitted to breath before sampling, while others were not. The aorta and pulmonary trunk served as controls. The objectives of the study were to identify the earliest cellular alterations leading to closure of the DA, to study in detail the sequence of cellular changes in closure of the DA, and to correlate these observations with what is known about the physiological factors involved in closure of the DA. Changes in the architecture of the DA wall were seen as early as on the twenty‐sixth day of gestation and involved the appearance of increased numbers of radially or longitudinally reoriented smooth muscle cells in the intima and fragmentation of the internal elastic lamina. The progress of these changes continued and intensified until the end of gestation. At that stage the inner one‐half of the medial smooth muscle cells was reoriented, and the lumen was significantly reduced by a greatly expanded intima which often contained many intercellular “ghost bodies.” Very few mitoses were seen during DA closure, especially during 29 to 31 days of gestation. It is concluded that cellular changes involved in closure of the DA of the rabbit fetus begin far in advance of birth and breathing. These cellular changes are highly analogous to those which occur in the early pathogenesis of arterial intimal fibromuscular lesions. Closure of the DA, therefore, seems to afford an excellent, natural model for study of key cellular events involved in the production of arterial fibromuscular lesions.
Changes in length of sarcomeres following tenotomy of the rat soleus muscle
Authors: Baker James H. , Hall‐Craggs E. C. B. 
Published: February 2005

AbstractTenotomy of the proximal and distal tendons of the soleus muscle of female Wistar rats was performed and sarcomeric length and muscle fascicle length measured. On the first postoperative day muscle bellies were found shortened and their sarcomeric length considerably reduced. Four weeks following tenotomy, although the muscle bellies remained shortened, sar‐comeric length was comparable with that of control muscles. Measurement of muscle fascicle lengths at this time showed that those of experimental muscles were nearly 50% less than those of control muscles. It was concluded from these experiments that a reduction of the number of sarcomeres in series had occurred, thus compensating for the reduced length of the muscle belly.