bluuebunny/crossref_metadata_2025_split huggingface dataset:
Permeability to lanthanum of blood testis barrier in human germinal aplasia
Authors: Camatini Marina , Franchi Emilia , Decurtis Ivan 
Published: February 2005

AbstractThe permeability of Sertoli tight junctions to lanthanum administrated during fixation is demonstrated in biopsies of patients with partial germinal aplasia. In freeze‐fracture replicas the number of fibrils is not significantly different from the data obtained in normal testis. Thus, in these pathological conditions junctional permeability is not related solely to the complexity of the network revealed by freeze‐fracture.
Innervation of rat antral gastrin‐producing cells
Authors: Lechago Juan , Barajas Luciano 
Published: February 2005

AbstractThe innervation of rat antral gastrin‐producing cells (G‐cells) was studied by light and electron microscopy. Combination of histochemistry for acetylcholinesterase and immunofluorescence for gastrin in the same tissue section showed apparent contact between some of the G‐cells and acetylcholinesterase‐positive nerves. Electron microscopic observation, however, revealed gaps of 200–500 nm or more between the G‐cells and the closest nerve axons which often contained large dense‐cored vesicles. The latter may represent the storage sites for neuropeptides previously localized by immunohistochemistry in gastric nerves.
Hypertrophic and hyperplastic effects of thyroxine on the submandibular gland of the mouse
Authors: Gresik E. W. , van der Noen H. , Barka T. 
Published: February 2005

AbstractThe nature of the trophic response of the mouse submandibular gland to thyroxine (T4) was examined. Adult female Swiss‐ Webster mice were given daily subcutaneous injections of T4 (1 μg/gm body weight) for two or four days; two injections of tritiated thymidine (3H‐ TdR) were given 24 and 29 hours after the last injection of hormone, and the mice were killed one hour after the last injection of 3H‐ TdR. One gland was analyzed chemically for DNA content and for incorporation of 3H‐ TdR, while the other was used to prepare autoradiograms. The cellular composition of each gland was analyzed by counting 1000 nuclei, and the frequency and labelling index (LI) of six cell types were established. A rise in specific activity of DNA and a fall in its concentration were seen in response to T4. The LI for the entire gland more than doubled. The LIs and frequencies of granular convoluted tubule and granular intercalated duct cells were increased more than those of acinar and nongranular intercalated duct cells; striated and excretory duct cells were not affected. It is concluded that the enlargement of the submandibular gland of the mouse caused by T4 is due to both hyperplastic and hypertrophic effects.
Organization of collagen in the human pulmonary alveolar wall
Authors: Rosenquist Thomas H. 
Published: February 2005

AbstractThe purpose of this study was to determine the organization of collagen in the wall of the human pulmonary alveolus. Samples of human lung obtained at surgery were processed for light and electron microscopy. Light microscopy confirmed the general findings of Orsos ('36): there were 3 common fibers called primary, secondary, tertiary in this study in order of their increasing size. Primary fibers (called “pericapillary” by Orsos) formed a continuous mesh in the alveolar wall and were often confluent within the intercapillary regions of the wall (“knötenpunkten,” or nodes, Orsos). The tortuous secondary fibers (“circulatory fibers,” Orsos) passed frequently across the thickness of the alveolar wall and were closely applied to capillary walls. Tertiary fibers (“respiratory fibers,” Orsos) were continuous with the alveolar ostia and formed the supportive struts of the alveolar wall as they crossed the wall in a more direct course than the serpiginous secondary fibers.Electron microscopy (serial sections and stereo pairs) showed that the primary fibers inserted near the edge of an intercapillary region, where they were attached to the endothelial or epithelial basal lamina directly or by a smaller fiber or microfibril resembling the fibrous component of elastin or oxytalan. Primary fibers passed through a typical intercapillary region while describing a helix or a portion thereof. Secondary fibers were more coarse than primary, and both secondary and tertiary fibers resembled woven ropes.
Uptake of radioiodine in follicles of dog C‐cell complexes studied by autoradiograph and immunoperoxidase staining
Authors: Kameda Yoko , Ikeda Kazuo , Ikeda Akira 
Published: February 2005

AbstractC‐cell complexes are special cell groups consisting of a mass of C‐cells associated with other epithelial elements and cysts. They are remnants of ultimobranchial bodies retaining fetal characteristics. In the C‐cell complexes there are follicular cells in various stages of differentiation, i.e., the cell clusters not yet organized into follicles, primordial follicles with small lumens and comparatively enlarged follicles storing plentiful amounts of colloid. They have a morphology similar to follicular cells of fetal thyroid glands and react to antiserum to 19S thyroglobulin. In order to determine whether or not the follicles in these complexes have the ability to incorporate radioiodine, autoradiography after a single injection of 125I was combined with immunoperoxidase staining using specific anti‐calcitonin, anti‐C‐thyroglobulin, and anti‐19S thyroglobulin antisera. The 19S‐positive cells not yet organized into follicles did not take up radioiodine. Primordial follicles showed a heavy accumulation of silver grains over their follicular lumens storing new 19S thyroglobulin as colloid. Comparatively enlarged follicles revealed a strong autoradiographic reaction and their labeling patterns were identical with those of typical thyroid follicles. These results confirm that the follicles in C‐cell complexes, as well as thyroid follicles, can incorporate radioiodine and are related to thyroid hormone synthesis. That is, functional thyroid follicles can arise from the ultimobranchial bodies.
A quantitative morphological analysis of interatrial muscle cells in the ferret heart
Authors: Marino Thomas A. , Biberstein Denise , Nong Cook P. , Cook Larry , Dwyer Samuel J. 
Published: February 2005

AbstractCells located in the interatrial septum of the ferret heart were examined and mean cell volume, surface area, length, width, as well as cell length/width and surface area/volume ratios were obtained. The muscle cells were from two different regions. One region was the area of the middle internodal tract while the other was from the area where the anterior and middle internodal tracts intermingled. Based on the data obtained, at least two different subpopulations of interatrial muscle cells could be defined. The larger cells had a mean cell length of 109.7 μm, a mean cell width of 13.1 μm, a length/width ratio of 8.61, a mean cell surface area of 5,057.6 μm2, a mean cell volume of 5960.8 μm3, and a surface area/volume ratio of 0.87. The smaller cells had a mean cell length of 58.0 μm, a mean cell width of 12.2 μm, a length/width ratio of 4.85, a mean cell surface area of 2494.1 μm2, a mean cell volume of 2553.6 μm3, and a surface area/volume ratio of 1.00. The large cell population had cells that were myofibril rich and also others that were myofibril poor. These quantitative data indicate that the regions of internodal pathways are not composed of a single specialized cell type, but rather are composed of at least two, if not more, cell types that intermingle with each other.
Some effects of protein‐calorie undernutrition on the developing central nervous system of the rat
Authors: Noback Charles R. , Eisenman Leonard M. 
Published: February 2005

AbstractSome effects of undernutrition were noted in the brains of 21‐day‐old rat pups undernourished from birth by being reared by nursing dams fed on a low protein diet. As compared to the normally fed control pups, the body weight, brain weight, and thickness of the parietal neocortex and paravermal cerebellar cortex were significantly lower in the undernourished pups (p < 0.001), while the thickness of the cortices of the dentate gyrus and hippocampus CA3 only reached significance at the 5% level. Again, as compared to the control pups, the number of spines per unit length on the distal dendritic segments of the pyramidal cells of lamina III of the parietal neocortex and of the hippocampus CA3 reached significance at the 5% level whereas that of the granule cells of dentate gyrus and Purkinje cells of the paravermis did not reach significance at the 5% level. The myelination of the pyramidal tract and spinal trigeminal tract in the lower medulla was less advanced in the undernourished pups.To date, the demonstration of precise functional correlates for the observed changes of morphological and physiological parameters in animals subjected to undernutrition has been elusive. An approach that may lead to unraveling this problem is suggested in a discussion of relating sources of input to the specific dendritic segments where the spine counts were made.
Central connections of the olfactory bulb in the american opossum (didelphys virginiana): A light microscopic degeneration study
Authors: Meyer R. Peter 
Published: February 2005

AbstractDestructive lesions were made in the right olfactory bulb of 16 adult opossums. Following postoperative survival periods of 4 to 31 days, the animals were sacrificed and perfused with 10% Formalin. Frozen sections of the brain were cut in either the coronal, horizontal, or sagittal plane and processed by the Fink‐Heimer II method. Degenerating axons of olfactory bulb neurons were traced caudally in the ipsilateral lateral olfactory tract (LOT). Small lesions revealed a topographic representation of the olfactory bulb within the LOT. The dorsal, lateral, and ventral parts of the bulb were, respectively, represented in the dorsal, intermediate, and ventral parts of the LOT. Terminal degeneration was observed in the superficial half of the molecular layer ipsilaterally in the following structures: anterior olfactory nucleus, anterior hippocampal rudiment, olfactory tubercle, piriform cortex, ventrolateral frontal neocortex, lateral entorhinal cortex, nucleus of the LOT, and the lateral aspect of the cortical amygdaloid nucleus. No degeneration was observed in the anterior limb of the anterior commissure. Dorsal and lateral parts of the olfactory bulb projected to the anterolateral aspect of the olfactory tubercle, whereas the ventral part projected heavily to the entire tubercle. There was no evidence of topographic projections to other olfactory structures. The observations of the present investigation indicated that the olfactory bulb projections in the opossum, a primitive mammal, are essentially comparable with those of placental mammals.
Changes in the surface morphologies of the cells in the bursa cloacalis (bursa of Fabricius) and thymus during ontogeny of the chick embryo
Authors: Schoenwolf Gary C. , Singh Upendra 
Published: February 2005

AbstractSlices or sections through the bursa cloacalis and thymus of chick embryos at 7–21 days of incubation were observed by light and electron microscopy to determine whether major differences existed in the surface morphologies of lymphoid cells in these organs, and whether the surface morphologies of these cells changed during ontogeny. These organs were fixed concurrently and identically at each stage.The thymus was packed at all stages with spherical cells having fine structures characteristic of those of lymphoid cells. Many irregularly shaped, epithelial cell processes were present between lymphoid cells.The bursa contained many irregularly shaped stromal cells as well as spherical cells. The latter were few in number during early development, but became the predominant type of cell near the end of incubation. Spherical cells in the bursa consisted of three types based on fine structure: lymphoid cells, granulocytic cells, and cells which were probably precursors of granulocytic cells. Spherical cells in the bursa could not be classified into these three types by their surface morphologies, however, because the latter at any one stage of development were similar. At 7–8 days of incubation, spherical cells in the bursa could not be differentiated consistently from neighboring stromal cells by scanning electron microscopy alone, but by 9 days, spherical cells could be identified routinely by this method.At 9–10 days of incubation, only minor differences existed in the surface morphologies of the spherical cells in the bursa and thymus: Bursal cells displayed long, ridgelike processes, whereas thymic cells exhibited fine surface undulations and large blebs. At 11 days, the surfaces of the spherical cells in the bursa were covered by numerous short microvilli, but the surfaces of thymic cells were unchanged. Bursal cells retained their microvilli through 14 days of incubation, but between 15 and 21 days progressively lost their microvilli, becoming essentially bald near the end of this period. Likewise, thymic cells gradually lost their surface wrinkles and blebs. Near the time of hatching, both types of cells were smoothsurfaced and tightly packed, with individual cells assuming polyhedral configurations.
Satellite cell distribution within the soleus muscle of the adult mouse
Authors: Snow Mikel H. 
Published: February 2005

AbstractThe frequency of satellite cells was quantitated by electron microscopy in five proximal to distal regions of the soleus muscle of adult mice. In all, 236 satellite cell nuclei and 4,475 myonuclei were counted on 51 transverse thin sections. The mean percentage of satellite cells, as a ratio of satellite cells to myonuclei, per region was found to be 5.4%, 5.3%, 5.0%, 5.2% and 4.9% for the most proximal to distal areas, respectively. Analysis of variance revealed no significant differences between either the regions or the animals studied. The number of satellite cell nuclei per cross‐sectional area of muscle was also calculated for each of the five regions, and these values did not vary significantly from the proximal to distal ends of the muscle. Despite the fact that satellite cells were frequently noted in close association with cross‐sectional profiles of myoneural junctions, this study establishes that the number of such perisynaptic satellite cells was not large enough to affect significantly the mean percentages of all satellite cells counted within the motor endplate regions (areas 3 and 4) of the soleus muscle. It is concluded from this study that satellite cells are uniformly distributed throughout the whole muscle.
The structure of bursae ovaricae surrounding the ovaries of the golden hamster
Authors: Martin Gary G. , Sack Marty , Talbot Prudence 
Published: February 2005

AbstractThe ovaries of many mammals lie within membranous sacs called bursae ovaricae. In this study, we have examined the morphology of the bursa surrounding the hamster ovary using light and electron microscopy. The bursa is composed of three layers: (1) an inner, discontinuous bursal epithelium that faces the ovary; (2) a middle layer of connective tissue that contains fibroblasts, bundles of smooth muscle cells, and blood vessels; and (3) an outer, continuous epithelium that faces the peritoneal cavity. One side of the bursa has a thin layer of connective tissue, and because the ovary may be seen through it, we refer to this region of the bursa as the “window”. Elsewhere a thick layer of fat joins the connective tissue and blocks visualization of the ovary. Tracers (Evans blue and lanthanum) applied to the peritoneal surface do not penetrate beyond the peritoneal epithelium. Tracers injected into the bursal cavity penetrate all layers of the bursa, but do not pass through the peritoneal epithelium. Therefore, the bursa prevents tracer exchange between the bursal and peritoneal cavities, but exchange does take place between the bursal cavity and blood vessels within the bursa. We suggest that bundles of smooth muscle cells within the bursa may serve to regulate fluid volume and pressure within the bursal cavity. Possible functions of the complete bursa in the hamster are discussed.
The effects of castration on size and appearance of Sharpey's fibers of rat femurs: A scanning electron microscopic and microradiographic study
Authors: Wink Carole S. 
Published: February 2005

AbstractAreas of Sharpey fiber bone from the proximal posterior diaphyseal surfaces of anorganic control and castrate osteopenic rat femurs were examined with the scanning electron microscope (SEM). The diameter of Sharpey fiber bundle insertion sites from castrate bone was significantly greater (P ≤0.001) than that from control bone. The fiber bundle insertions appeared as small pits and projections in control bone and as large pits in castrate bones. Microradiographs of cross sections of the Sharpey fiber bone revealed a greater (P ≤ 0.05) area of outer, lamellated periosteal bone in the castrates than in the controls, suggesting an accelerated bone apposition rate along castrate osteopenic femoral periosteal surfaces.
The histology and fine structure of glands in the rat respiratory tract
Authors: Spicer S. S. , Setser M. E. , Mochizuki I. , Simson J. A. V. 
Published: February 2005

AbstractThe structure of rat respiratory glands has been investigated by light and electron microscopy. The glands exhibited a tubulo‐acinar organization. Individual secretory units were composed of serous tubules or serous demilunes and mucous tubules with narrow lumens at the blind end (proximally), and of mucous ducts with wide lumens which opened to the tracheal lumen distally. Near the junction of the duct with the trachea, mitochondria‐rich cells and a few ciliated cells were interspersed with mucous cells. It was found that the histology as well as the ultrastructure of the secretory product of these gland cells varied depending upon the location of the glands in the airway. For this reason, the glands of the epiglottis, larynx and trachea have been described separately. Epiglottal glands consisted of many mucous tubules, a few serous elements and an occasional mucous duct. Laryngeal glands contained many serous and mucous tubules and a few mucous ducts. Tracheal glands were composed of serous tubules, a few mucous tubules and prominent mucous ducts. Serous tubule cell granules formed a uniform population within a cell profile but varied in cells of the epiglottis, compared with those of the larynx and trachea. Granules in mucous tubule cells differed from those of serous cells. Mucous cell granules also appeared uniform within a single cell but differed from cell to cell and at different levels of the respiratory tract. A particular granule type was predominant at each level. Cells of mucous ducts differed somewhat from those of mucous tubules and comprised two general secretory cell populations. Proximal mucous duct cells contained abundant granules that generally resembled those of mucous tubule cells but were localized in two areas of the cytoplasm. Dilated cisternae of rough endoplasmic reticulum with a bizonal content similar in density to zones seen in mature granules further characterized proximal mucous duct cells. The distal mucous duct cell generally contained sparse apical granules and lacked dilated rough endoplasmic reticulum.
A freeze‐fracture study of the guinea pig yolk sac epithelium
Authors: King Barry F. 
Published: February 2005

AbstractThe yolk sac epithelium functions in endocytic absorption of macromolecules from the uterine lumen and in maintaining permeability barriers between the maternal (uterine) compartment and underlying fetal compartments. In this study, cell membranes and intercellular junctions of the guinea pig yolk sac were examined using the freeze‐fracture technique. Intramembranous particle (IMP) distribution and size were examined in microvilli, intermicrovillous membrane, and endocytic pits. IMPs on the P‐fracture face were not evenly distributed within these membrane domains and the IMPs were of several sizes. In addition, short filamentous strands sometimes bridged between the cytoplasm and the E‐face of endocytic pit membranes. These results indicated that the regions of yolk sac cell membrane involved in endocytosis did not have unusual numbers or distributions of IMPs compared to other membrane regions. The intercellular junctions between endoderm cells consisted of zonulae occludentes, gap junctions, and desmosomes. The zonula occludens usually consisted of four or five interconnected strands or ridges, and were elaborately developed where three cells abutted one another. Gap junctions were infrequent, small, and often associated with the zonula occludens. Desmosomes were observed both as typical macular structures and as more extensive, elongated structures. These results confirm previous thinsection studies of yolk sac indicating the presence of tight junctions. However, the extent of development of tight junctions does not correlate with the reported absence of a potential difference across yolk sac epithelium. The presence of gap junctions does not confirm results of previous freeze‐fracture studie sof other yolk sacs.
Morphology and distribution of microtubules in the presecretory and secretory ameloblasts of the rat incisor
Authors: Nishikawa Sumio , Kitamura Hironori 
Published: February 2005

AbstractThe morphology and distribution of microtubules in the ameloblast of the rat incisor were examined. Two types of microtubules distribution were observed: isolated single tubules and multiple tubules. The latter formed bundles of tubules and filaments or sheets of filaments. The thickness of the filament or sheet was almost the same as that of the wall of the microtubule. The filament or sheet as well as the microtubule were negatively stained when treated with tannic acid. The microtubules of the single type were small in number at the undifferentiated stage of the cell. They increased in number in the distal portion of the cell during differentiation, and their number reached a peak in the proximal portion of Tomes' process at the secretory stage of the cell. On the other hand, the multiple microtubules showed a different distribution in the secretory stage of the cell, i.e., they were mostly distributed between the Golgi region and the distal terminal web.
The distribution of satellite cells and their relationship to specific fiber types in soleus and extensor digitorum longus muscles
Authors: Gibson Marcia C. , Schultz Edward 
Published: February 2005

AbstractFiber type classification of p‐phenylene‐diamine‐stained transverse sections of rat skeletal muscle correlated with electron microscopic observations demonstrate that satellite cells are not equally distributed among the various fiber types in either the EDL or soleus at 1 and 12 months of age. Of the three fiber types in the EDL, satellite cells are observed most frequently on Type IIA fibers, and at approximately equal frequencies on Type IIB and Type I fibers. Satellite cells in the soleus, in contrast to the EDL, are not often encountered on Type IIA fibers, but are preferentially associated with Type I fibers in that muscle. The frequency with which satellite cells are found on specific fiber types is distinct for the soleus and EDL and appears to correspond with their growth characteristics. The distribution of satellite cells according to fiber type does not provide an explanation for the differences in the percentage of satellite cell nuclei between the EDL and soleus.