bluuebunny/crossref_metadata_2025_split huggingface dataset:
The tracheobronchial epithelium of the bonnet monkey (Macaca radiata): A quantitative ultrastructural study
Authors: Wilson Dennis W. , Plopper Charles G. , Hyde Dallas M. 
Published: February 2005

AbstractSince there are major differences between the airway epithelium of man and that of common laboratory species, the tracheobronchial epithelium of the bonnet macaque was characterized to evaluate its usefulness as a model for study of human conducting airways. This study compared the light microscopic, scanning electron microscopic, and ultrastructural appearance of epithelium from the posterior membranous and anterior cartilaginous trachea and mainstem bronchus. Population densities, epithelial volumetric densities, and frequency distributions of cross‐sectional areas of nuclei were determined for cell types present on electron micrographs. Four epithelial cell types were distinguished by ultrastructural criteria. Basal cells were 31% of the population and were similar to those described in other species. Ciliated cells were also similar to those of other species and composed 41% of the population; their nuclei were larger than those of other cell types. Mucous goblet cells had large numbers of secretory granules with electron‐dense cores and a lucent periphery. They were only 8% of the population by nuclear count but composed 20% of the epithelial volume. The fourth cell type had multiple small vesicles containing small amounts of granular material and was termed a “small mucous granule cell.” Small mucous granule cells (16% of the population) were present in greater numbers than mucous goblet cells but were a smaller proportion of the epithelial volume (8%). While population densities of cell types determined from transmission electron micrographs did not vary between sample sites, scanning electron microscopy demonstrated longitudinal streaks of secretory cells in the posterior trachea suggesting that regional differences in epithelial organization exist. We conclude that the macaque extrapulmonary airway epithelium differs from published descriptions of laboratory rodents in both cell types present and relative abundance of those cell types. Although detailed quantitative studies of human extrapulmonary airways are not available, the primate airways resemble those of man in both the types of cells present and the complexity of pseudostratification.
Endocytosis in nonciliated epithelial cells of the ductuli efferentes in the rat
Authors: Hermo L. , Morales C. 
Published: February 2005

AbstractThe nonciliated cells lining the ductuli efferentes presented three distinct cytoplasmic regions. The apical region contained, in addition to cisternae of endoplasmic reticulum and mitochondria, two distinct membranous elements. The tubulovesicular system consisted of dilated tubules connected to the apical plasma membrane and subjacent distended vesicular profiles. The apical tubules, not connected to the cell surface, consisted of numerous densely stained tubules of small size which contain a compact, finely granulated material. The supranuclear region, in addition to a Golgi apparatus and ER cisternae, contained dilated vacuoles, pale and dense multivesicular bodies, as well as numerous dense granules identified cytochemically as lysosomes. The basal region contained the nucleus and many lipid droplets. The endocytic activity of these cells was investigated using cationic ferritin (CF) and concanavalin‐A‐ferritin (Con‐A‐ferritin) as markers of adsorptive endocytosis; and native ferritin (NF), concanavalin‐A‐ferritin in the presence of α‐methyl mannoside, and horseradish peroxidase or albumin bound to colloidal gold for demonstrating fluid‐phase endocytosis. These tracers were injected separately into the rete testis, and animals were sacrificed at various time intervals after injection. At 1 min, CF or Con‐A‐ferritin were seen bound to the apical plasma membrane, to the membrane of microvilli, and to the membrane delimiting elements of the tubulovesicular system. Between 2 and 5 min, these tracers accumulated in the densely stained apical tubules and at 15 in min the dilated vacuoles. Between 30 min and 1 hr, the tracers appeared in multivesicular bodies of progressively increasing density, whereas at 2 hr and later time intervals, many dense lysosomal elements became labeled. The tracers for fluid‐phase endocytosis showed a distribution similar to that for CF or Con‐A‐ferritin except that they did not bind to the apical plasma membrane, microvilli, or membrane delimiting the tubulovesicular system. At no time interval were any of the tracers observed in the abluminal spaces. Thus, the nonciliated epithelial cells of the ductuli efferentes are actively involved in fluid‐phase and adsorptive endocytosis, both of which result in the sequestration of endocytosed material within the lysosomal apparatus of the cell.
Muscle fiber termination at the tendon in the frog's sartorius: A stereological study
Authors: Eisenberg Brenda R. , Milton Richard L. 
Published: February 2005

AbstractThe force produced within skeletal muscle fibers is transmitted to the bone via a myotendinous junction. This junctional region was examined by light and electron microscopy in the sartorius muscles of three Rana temporaria. The muscle fibers tapered and inserted at an angle of about 25° with the connective tissue fascia near the bone. The composition of the structures within the last 100 μm of the fiber was analyzed morphometrically. The T‐system, terminal cisternae, and caveolae were the same as in the central region of the muscle fiber. However, the mitochondrial content was higher and the volume of longitudinal sarcoplasmic reticulum was lower than elsewhere in the fiber. The membrane at the end of the fiber had extensive villiform processes interdigitating with the tendon. The surface area of the membrane around the villiform processes was estimated with point‐counting techniques and calculated from the stereological equations appropriate for partially anisotropic structures. The extra membrane involved in the myotendinous junction was about 32 times that of the cross‐sectional area of the fiber. Part of this additional membrane contained specialized adherens junctions through which the contractile proteins of the muscle are anchored to collagen. The increased area at the myotendinous junction presumably provides greater mechanical strength than a flat termination. The high values of membrane capacitance and specific resistance measured electrophysiologically at the end of the fiber also can be attributed to the characteristics of the terminal membrane structure.
Architectural design and fiber‐type distribution of the major elbow flexors and extensors of the monkey (cynomolgus)
Authors: Roy Roland R. , Bello Maureen A. , Powell Perry L. , Simpson Don R. 
Published: February 2005

AbstractBecause the architectural and biochemical properties of a skeletal muscle dictate its force, velocity, and displacement properties, the major extensors (triceps brachii) and flexors (biceps brachii, brachialis, and brachioradialis) of the elbow in a primate (cynomolgus, monkey) were studied. Functional cross‐sectional areas (CSA) were calculated from muscle mass, mean fiber length (normalized to a 2.20 μm sarcomere length), and angle of fiber pinnation measurements from each muscle. Fiber‐type distributions were determined and used as a gross index of the biochemical capacities of the muscle. The extensor group had a shorter mean fiber length (31 vs. 47 mm), a larger CSA (13 vs. 8 cm2), and a higher overall percentage of slow‐twitch fibers (47 vs. 26%). Consequently, the elbow extensors had a relatively greater potential for force production and force maintenance than the flexors. In contrast, the flexors were designed to optimize their length‐velocity potentials; i.e., they had relatively long fibers and a higher fast‐twitch fiber composition than the extensors. These morphologic differences between antagonistic muscle groups should be considered when evaluating the motor control mechanisms regulating reciprocal movements about the elbow.
Mitochondrial reorganization during resumption of arrested meiosis in the mouse oocyte
Authors: Van Blerkom Jonathan , Runner Meredith N. 
Published: February 2005

AbstractCorrelated nuclear and cytoplasmic reorganizations during the 14 hr of reactivated meiosis in vivo and in vitro were examined in the laboratory mouse. Observations of living oocytes by differential interference contrast microscopy, and by fluorescent microscopy with nontoxic mitochondrial and DNA‐specific probes, enabled us to determine that the major cytoplasmic reorganization involved two mitochondrial translocations associated with two stages of nuclear maturation. These observations were confirmed at the fine structural level by parallel transmission electron microscopy. Mitochondria translocate to the perinuclear region during formation of the first metaphase spindle and subsequently disperse during abstriction of the first polar body. Determinations of frequency of maturation in more than 2,900 normal oocytes, and in more than 1,100 oocytes in which germinal vesicle breakdown was reversibly inhibited, indicated that mitochondrial redistributions are a normal and probably necessary feature of reactivated meiosis in the laboratory mouse. We suggest that these two rapid translocations serve to concentrate mitochondria for localized activities that require elevated levels of adenosine triphosphate.
Morphometric analysis of the pineal complex of the golden hamster over a 24‐hour light: Dark cycle: I. The superficial pineal in untreated and optically enucleated animals
Authors: Dombrowski Teresa A. , McNulty John A. 
Published: February 2005

AbstractMorphometric analysis of the superficial pineal gland of intact and blinded golden hamsters was conducted at both the light and electron microscopic level. The volume of the superficial gland was estimated to be 151 × 106 μm3, comprising 90–94% of the total pineal parenchymal tissue. Analysis of structural rhythms in animals maintained under a 14:10 L:D cycle showed significant 24‐hr variations in values for pinealocyte nuclei, nucleoli, rough and smooth endoplasmic reticulum, Golgi bodies, dense bodies, and dense‐cored vesicles. Peak values for these structures generally occurred at the light:dark interface. These results provide morphological correlates for known rhythmic variations in the synthesis of pineal‐gland products. Superficial pineals examined 8 weeks following optic enucleation exhibited a decrease in the volume of pinealocyte nuclei and cytoplasm, while nucleolar size and the amounts of smooth and rough endoplasmic reticulum, Golgi bodies, dense bodies and dense‐cored vesicles were enhanced. The latter changes are interpreted as indications of increased synthetic activity by the superficial pineal gland in response to light deprivation.
Morphometric analysis of the pineal complex of the golden hamster over a 24‐hour light: Dark cycle: II. The deep pineal in untreated and optically enucleated animals
Authors: Dombrowski Teresa A. , McNulty John A. 
Published: February 2005

AbstractThe deep pineal gland of golden hamsters was morphometrically analyzed and quantitatively compared with the superficial pineal under a 14:10 lighting regime and following blinding. The deep pineal comprised 6–10% of the total pineal parenchymal tissue. Pinealocytes of the deep gland were smaller than the cells of the superficial pineal and showed a greater percent volume of Golgi bodies, rough endoplasmic reticulum, and dense‐cored vesicles. Twenty‐four‐hour rhythms in nucleoli and Golgi bodies were found in deep pinealocytes. These rhythms were out of phase with comparable rhythms in the superficial pineal gland, suggesting that distinct subpopulations of pinealocytes are present within the respective parts. Blinding resulted in decreased nuclear and nucleolar volume, while the amount of smooth endoplasmic reticulum, Golgi bodies, dense bodies, and dense‐cored vesicles increased significantly. Marginal increases were seen in mitochondria and lipid droplets. The greater abundance of those organelles involved in synthesis and secretion suggests enhanced cellular activity after blinding. Many of the morphological responses are similar to alterations in the pinealocytes of the superficial pineal following optic enucleation.
A light and fluorescence cytochemical and electron microscopic study of granule‐containing cells in the intrapulmonary ganglia of Pseudemys scripta elegans
Authors: Scheuermann D. W. , De Groodt‐Lasseel M. H. A. , Stilman C. 
Published: February 2005

AbstractIn the lung of the red‐eared turtle, large numbers of intramural ganglia located in the intraparenchymal connective tissue are demonstrated. Numerous cells in close proximity to the principal ganglionic neurons displayed a bright blue‐white formaldehyde‐induced fluorescence. Microspectrofluorometric analysis revealed the presence of dopamine (DA) in all cells measured. Subsequent light histochemcial staining of the fluorescent sections showed the DA‐containing cells to display argentaffinity. Electron microscopy of serial sections revealed cells characterized by dense‐cored vesicles corresponding to the intensely formaldehyde‐induced fluorescent cells. The argentaffin technique performed directly on ultrathin sections selectively stained the dense‐cored vesicles. After fixation with glutaraldehyde followed by dichromate, x‐ray microanalysis showed the chromium to be incorporated into the dense granules. Cholinergic‐type nerve endings formed axosomatic synaptic contacts with the DA‐containing cells, which can therefore be considered as intrinsic postganglionic elements. No efferent synapses from the granule containing cells to the principal ganglionic neurons could be observed. The granule‐containing cells occurred solitarily and in clusters, partially invested with satellite cells, and usually located near fenestrated capillaries; they displayed cytoplasmic processes and indicated emiocytotic granule release. Adjacent granule‐containing cells were separated by spaces about 20 nm wide, gradually widening to form intercellular channels with apically projecting microvilli and primary cilia. It is concluded that the intrapulmonary granule‐containing cells of the red‐eared turtle belong to the APUD system. Furthermore, morphologically these cells appeared to possess a special sensory apparatus which designates them as paraneurons. The possible physiological significance of these intrapulmonary granule‐containing cells is discussed.
The three‐dimensional architecture of the elastic‐fiber network in canine hepatic portal system
Authors: Crissman Robert S. , Guilford William 
Published: February 2005

AbstractThe architectural arrangement of the elastic‐fiber network in the wall of canine hepatic portal veins was observed with the scanning electron microscope (SEM). Selective NaOH sonication digestion and autoclaving were used to expose and isolate the networks of elastic fibers from six selected regions of the hepatic portal vessels from seven healthy dogs. Elastic stains of adjacent segments prepared for light microscopy demonstrated that the elastic fibers were concentrated in two areas within the intact portal wall. The innermost area corresponded to the internal elastic lamina (IEL) of the tunica intima, the internal muscular layer, and the connective tissue layer of the tunica media. The second area was in the tunica adventitia. SEM specimens revealed two sleeves of elastic fiber networks which corresponded to the above regions. Small scattered bundles of radially oriented elastic fibers spanned the gap between the two sleeves. Each tunica had a different architectural arrangement of elastic fibers. The IEL had circumferentially oriented fibers which branched and anastomosed to form a continuous network on the innermost surface. The architecture of the IEL was the most variable between the different regions. The network of the IEL was the most “open” in the caudal region (splenic vein) and became “denser” toward the liver. The large elastic fibers inthe tunica media were oriented at approximately right angles to the primary fibers of the IEL. These longitudinally oriented fibers anastomosed with adjacent longitudinal fibers to form a continuous network. In the tunica adventitia, thick, longitudinally oriented fibers of the continuous network fused together to form incomplete layers of fibers. The architecture of the elastic‐fiber network in the canine hepatic portal vein was compared to that previously described in the systemic canine saphenous vein.
Validation of cell volume determination for stereological studies of adrenocortical cells: Comparison of values from semifine sections with those of dissociated zona fasciculata cells
Authors: Taki Taki M. , Nickerson Peter A. 
Published: February 2005

AbstractThe average cell volume of rat adrenocortical zona fasciculata cells, determined using three different stains on semifine sections, was compared to that of dissociated, unfixed zona fasciculata cells. The maximum number of nuclei per area (NA) was obtained by counting nuclear profiles in semifine sections from nonosmicated adrenocortical tissue stained with toluidine blue. In osmicated adrenocortical tissue on the other hand, fewer nuclear profiles were seen and more of the small size classes were missing from the distribution of profiles. The skewness of the nuclear‐profile distribution was much greater in osmicated than in nonosmicated tissue, reflecting the missing small profiles. Although the average diameter of nuclei (D) in nonosmicated tissue was smaller than that for osmicated tissue, profiles were in all likelihood more readily identified because they stained quite intensely. Three different methods for correcting nuclear‐size profile distribution and determining nuclei per volume (NV) (Giger‐Riedwyl, Cruz‐Orive, and Weibel‐Gomez) were generally in agreement for nonsmicated tissue. Considerable shrinkage occurred during preparation for electron microscopy, with the greater change occurring in nonosmicated tissue. Cell volume in osmicated tissue corrected for shrinkage varied considerably among the different methods, producing significantly greater values for cell volume than those in nonosmicated tissue. The cell volume of nonosmicated tissue, corrected for shrinkage during processing and for missing small nuclear profiles, did not differ significantly from that of freshly dissociated zona fasciculata cells. The one exception was nonosmicated tissue stained by Feulgen‐methylene blue and corrected for missing small nuclear profiles by the method of Cruz‐Orive. Use of nonosmicated adrenocortical tissue in stereological studies with an appropriate correction for shrinkage for each experiment is recommended for determining cell volume, although osmicated tissue should also be included to facilitate identification of intracellular membranes when electron microscopy is required.
Reduction of density and anisotropic distribution of intermediate filaments occur during avian skeletal myogenesis
Authors: Price Maureen G. , Sanger Joseph W. 
Published: February 2005

AbstractChicken skeletal muscle taken from embryos in ovo was examined by thin‐section electron microscopy. Measurements of filament diameters reveal three nonoverlapping groups of filaments: thin (actin myofibrillar) filaments with mean diameters of 5.3 ± 0.6 nm (S.D.), thick (myosin myofibrillar) filaments with mean diameters of 15 ± 1.4 nm, and intermediate filaments with mean diameters of 9.3 ± 0.9 nm. During muscle development these diameters do not change. By counting the number of filaments observed in the sarcoplasm at different stages, we find that the spatial density of intermediate filaments decreases during avian myogenesis in ovo, from 91 intermediate filaments/μm2 at 6 days to 43 intermediate filaments/μm2 at 17 days in ovo. Initially randomly arranged, some intermediate filaments become associated with Z discs, sarcoplasmic reticulum, nuclear membrane, and the sarcolemma between 6 and 10 days in ovo. These associated intermediate filaments course both parallel and transverse to myofibrils, forming lateral connections between myofibrillar Z discs and longitudinal connections from Z disc to Z disc within myofibrils. Intermediate filaments also appear to connect Z discs with the nuclear membrane. The intermediate filament associations persist through day 17 of development, after which the presence of cytoskeletal filaments is obscured by the densely packed myofibrils and membranes. Intermediate filament distribution becomes anisotropic during development. A greater proportion of intermediate filaments in the immediate perimyofibrillar area are oriented parallel to myofibrils than in other areas, so that the majority of the intermediate filaments nearest the myofibrils course parallel to them. The longitudinal intramyofibrillar intermediate filaments persist throughout development, as shown by their existence in KI‐extracted adult myofibrils.
Ultrastructural changes in the oviductal epithelium of merino ewes during the estrous cycle
Authors: Hollis D. E. , Frith P. A. , Vaughan J. D. , Chapman R. E. , Nancarrow C. D. 
Published: February 2005

AbstractIsthmic and ampullary oviductal epithelia sampled from Merino ewes at days ‐1, 1, 3, and 10 of the estrous cycle (estrus = day 0) were studied by scanning and transmission electron microscopy after fixation by vascular perfusion. Secretory cells, ciliated cells, and lymphocytelike basal cells were observed in both isthmic and ampullary epithelium at all stages of the estrous cycle studied and their ultrastructural features were analyzed. Synthesis of lamellated secretory granules occurred in the ampullary secretory cells during the follicular and early luteal phases, and their contents were released by exocytosis into the oviductal lumen during the luteal phase. Granule release was associated with nucleated apical protrusion of these cells into the oviductal lumen. No such secretory activity was displayed by isthmic secretory cells even though a few cells contained nonlamellated granules. Apocrine release of apical vesicles and accompanying cytoplasmic material from apical protrusions of ciliated cells occurred in the isthmus around estrus but not in the ampulla. This unexpected feature has not previously been reported in any other mammal. Dendritic basal cells were distinguished in the lower part of the epithelium by their heterochromatic nuclei, electron‐lucent cytoplasm, and lack of attachment zones. No migration of basal cells was observed, and their ultrastructural features were similar in the ampulla and isthmus and at all stages of the estrous cycle examined. The function of these lymphocytelike cells in the epithelium is uncertain, but the presence of phagocytic bodies and lysosomes in 20% of them may indicate a phagocytic role.