bluuebunny/crossref_metadata_2025_split huggingface dataset:
Light cells within the limiting membrane of rat seminiferous tubules
Authors: Hermo L. , Clermont Y. 
Published: February 2005

AbstractLight‐staining cells, distinct from myoid cells, were identified in electron micrographs of the limiting membrane of rat seminiferous tubules. While these cells were also found free in the interstitial space, they were observed mostly in the myoid cell layer of the limiting membrane but were never seen within the seminiferous epithelium itself. The light cells were characterized by a pale‐stained cytoplasm containing a spheroidal Golgi apparatus next to a polymorphous often kidney‐shaped nucleus, a few cisternae of rough endoplasmic reticulum and some granules of various types including multivesicular bodies.In hematoxylin‐stained whole mounts of dissected tubules, these light cells were readily identified under the light microscope by nuclear morphology and light‐staining juxtanuclear Golgi apparatus. The incidence of these cells, per unit surface area of tubular wall, was calculated, taking into consideration the stages of the cycle of the seminiferous epithelium with which they were associated. Distributed along the entire length of seminiferous tubules, their number varied significantly during the cycle. Low numbers were found in stages II–IV and XIII of the cycle, while high numbers were found in stages IX to XII and XIV–I of the cycle. These observations indicate that the seminiferous epithelium may exert an influence on the population of light cells present in the tubular limiting membrane.
The paraganglia, a persisting endocrine systen in man
Authors: Hervonen Antti , Vaalasti Annikki , Partanen Matti , Kanerva Lasse , Vaalasti Tapio 
Published: February 2005

AbstractThe paraganglia have been traced in surgical samples of para‐aortic and pelvic retroperitoneal tissues using the formaldehyde‐induced fluorescence method for catecholamines. Clusters of catecholamine‐storing cells were found in all (12) patients studied. Microspectrofluorometric recordings showed high amounts of catecholamine in the well‐vascularized cell groups. A large proportion of the paraganglia, which are most prominent during the fetal period, also persist during postnatal life.
Fine structure of the testis and epididymis of rats treated with cyproterone acetate
Authors: Flickinger C. J. , Loving C. K. 
Published: February 2005

AbstractAdult male rats were administered the antiandrogen, cyproterone acetate, for 4, 8 or 12 weeks, and the histology and fine structure of the testis and several parts of the epididymis were studied. After treatment for 8 or 12 weeks, the testes of treated animals displayed a great reduction in the abundance of late spermatids. Necrotic cells, many of which were identified as cap‐phase spermatids, were present in the seminiferous epithelium. Sertoli cells contained many large lipid droplets and lysosome‐like structures with a content of cellular debris, including parts of spermatids. Leydig cells of treated rats were smaller than those of control animals at all the intervals studied. Sperm were absent from the lumen of the middle segment, or caput epididymidis, of severely affected specimens. In the terminal segment, or cauda epididymidis, the microscopic appearance varied in different regions. In the proximal part of the cauda epididymidis, the lumen was usually clear of sperm. The epithelium was tall and the light cells were very large and distended with many dense bodies resembling lysosomes. In contrast, in the distal part of the cauda epididymidis, the lumen was filled with sperm and debris, which appeared to be derived from germ cells. It is suggested that the light cells of the epididymal epithelium may have a role in clearing the lumen in the proximal part of the cauda epididymidis, in which they are particularly large and numerous. The results suggest that in the presence of cyproterone acetate, germ cells develop up to cap‐phase spermatids and then begin to undergo degeneration and death. This alteration may have an important role in the antifertility effect of the drug, but changes in the epididymis may contribute also.
Observations on the microcirculatory bed in rat mesocecum using differential interference contrast microscopy in vivo and electron microscopy
Authors: Beacham W. S. , Konishi A. , Hunt C. C. 
Published: February 2005

AbstractThe microvascular bed of the rat mesocecum has been examined in vivo using differential interference (Nomarski) optics and subsequently by electron microscopy. The preferential channel, from terminal arteriole to collecting venule, has been examined.In the terminal arteriolar segment the endothelial layer is covered by a continuous layer of smooth muscle cells which, in turn, are surrounded by adventitia. In the metarteriolar segment the periendothelial cells still resemble smooth muscle cells but the tunica media is discontinuous. In the distal segment periendothelial cells are more scattered and have the appearance of pericytes. There appears to be a continuous transition of the periendothelial cell layer from terminal arteriole to distal segment.Nerve endings were seen in both the terminal arteriolar and metarteriolar segments.During contraction smooth muscle cells, oriented circumferentially, shorten and thicken. Endothelial cells appear anchored by myoendothelial junctions.Endothelial cells have filaments which show increased banding during vasoconstriction, suggesting that such cells may contract.Capillary offshoots leave the preferential channel, usually at right angles. Smooth muscle cells are oriented to form a sphincter and there are many myoendothelial junctions at the branch point. Within a short distance the capillary branch loses its periendothelial coat.
Selection of operating wavelength‐pair for two‐wavelength microspectrophotometry
Authors: Black‐Schaffer W. Stephen , Floyd Alton D. 
Published: February 2005

AbstractThe two‐wavelength method is the microspectrophotometric method of choice for thick specimens. Its accuracy is dependent on the accuracy of selection of the operating wavelength‐pair. The “slope zero test,” offered as a check upon the accuracy of this selection (Garcia and Iorio, ′66) is shown to be invalid by analysis of experimental data, by computer model and by mathematical derivation. A means of checking the accuracy of selection of the operating wavelength‐pair via scanning measurements is suggested. A new formulation of the two‐wavelength method, permitting use of different operating wavelength‐pairs, is also given.
The autonomic innervation of the interstitial gland of the rat ovary during pregnancy
Authors: Lawrence Irvin E. , Burden Hubert W. 
Published: February 2005

AbstractThe autonomic innvervation of the interstitial gland of the rat ovary was studied on days 4, 6, 10, 14 and 18 of pregnancy with the acetylcholinesterase procedure, the Falck‐Hillarp technique and electron microscopy after 5‐hydroxydopamine treatment. Acetylcholinesterase‐positive nerves were present as perivascular plexuses at all stages studied. Adrenergic nerves were present in the interstitial gland in all stages studied. The number and intensity of interstitial fluorescent adrenergic nerves increased as pregnancy progressed. Measurement of norepinephrine with the fluorometric procedure showed a highly significant (p < 0.05) increase in the neurotransmitter in the ovary on days 14 and 18 as compared to day 4. Fine‐structural studies after administration of the false transmitter, 5‐hydroxydopamine, showed that the innervation of the steroidogenic cells of the interstitial gland is adrenergic.
Functional differentiation of the chick endocrine pancreas. II. The alpha cells and glucagon
Authors: Benzo Camillo A. , Stearns Susan B. 
Published: February 2005

AbstractA radioimmunoassay for glucagon, together with electron microscopic observations of early embryonic alpha cells were utilized to examine developmental aspects of glucagon accumulation and release in the chick embryo. Immunoreactive glucagon was detected in both the pancreas and blood plasma from the fifth embryonic day onwards. In addition, emiocytotic events were observed in alpha cells as early as the fifth embryonic day. The early appearance of glucagon and its subsequent developmental profile correlate well with major events in carbohydrate metabolism occurring in the embryonic chick, and are discussed in relation to a functionally responding system, the developing liver. The present data show that glucagon is secreted at earlier embryonic stages than hitherto demonstrated, and suggest a developmental role for glucagon in hepatic glycogen metabolism.
Stereo high‐voltage electron microscopy of whole cells of the human diploid line, WI‐38
Authors: Wolosewick John J. , Porter Keith R. 
Published: February 2005

AbstractThe human diploid cell line, WI‐38, has proven to be an especially good object for high‐voltage electron microscopy using whole cells. Cells of intermediate passages were grown on plastic‐coated, carbon‐shadowed gold grids, fixed with glutaraldehyde, post‐fixed with osmium tetroxide, stained with uranyl salts and critical‐point dried. The absence of an embedding matrix produces images of increased contrast and resolution.The approach combined with stereo‐microscopy has extended our knowledge of cellular ultrastructure. Stereo‐images of whole cells reveal nuclei, mitochondria, microtubules, microfilaments, the endoplasmic reticulum and ribosomes in their expected forms. At high magnifications a continuity of microtubules, microfilaments and membranous elements with thin (3–6 nm) strands of the ground substance has been observed. These strands form a three‐dimensional lattice or mesh that pervades all parts of the cytoplasm. The entire structure is referred to as a microtrabecular lattice or mesh, the strands being the trabeculae. The inclusion of microtubules, microfilaments, ribosomes and vesicles of the endoplasmic reticulum within the material of the lattice makes them all part of a totally organized cytoplast.
Dissociation of epithelial cells from rabbit trachea and small intestine with demonstration of APUD endocrine cells
Authors: Sonstegard K. S. , Cutz E. , Wong V. 
Published: February 2005

AbstractIn this study the entire epithelial lining of tracheas and a 15‐cm segments of small intestine were dissociated into individual cell components after 45‐minute incubation with 1% pronase. Light and electron microscopy of isolated cells confirmed good morphologic preservation of various epithelial cell types dissociated from the trachea and small intestinal mucosa.Of particular interest was the recovery and preservation of APUD endocrine cells, which are known to be widely dispersed amongst various non‐endocrine epithelial cells in both the trachea and small intestine. The APUD cells were demonstrated in dissociated cell preparations by a formaldehyde‐induced fluorescence method, Grimelius' silver nitrate stain, and electron microscopy. The isolated APUD cells retained their characteristic features, e.g., amine‐handling properties, argyrophilia and cytoplasmic dense‐core vesicles.The cell dissociation method described in this report provides high yields of viable epithelial cells in single cell suspensions which are suitable for further cell separation into homogeneous populations of single kinds of cells, including the APUD endocrine cells. Availability of methods for isolation of tracheal and intestinal APUD cells will facilitate further studies, in vitro, on secretory, metabolic and functional aspects of these cells.
Age‐related change in the neuronal microenvironment: Penetration of ruthenium red into extracellular space of brain in young adult and senescent rats
Authors: Bondareff W. , Lin‐Liu S. 
Published: February 2005

AbstractThe volume of the extracellular space, which contributes to the microenvironment of neurons, is diminished in the brains of senescent (as compared to adult) rats and an age‐related change in its composition has been hypothesized. To test this hypothesis we have compared the penetration of ruthenium red, a polyanion selectively distributed in the extracellular space, into the dentate gyri of young adult and senescent Fischer 344 rats.Slices of hippocampal formation were fixed by immersion, first in a glutaraldehyde solution containing ruthenium red, then in a solution ofosmium tetroxide containing ruthenium red. A specific area of the dentate gyrus was identified, sectioned and examined by electron microscopy. Dense particles of ruthenium red reaction product were readily localized in intercellular channels and synaptic clefts and the depth of penetration was measured in a standardized manner so as to derive a mean depth of penetration for each of the 11 animals studied. A 28% decrease in the mean depth of penetration of ruthenium red in 25‐month‐old rats, as compared with 3‐month‐old animals, was found.These data indicate an age‐related change in the charge density of the intercellular channels in the dentate gyrus of 25‐month‐old rats. They suggest a primary age‐related change in the charge density of extracellular macromolecules, presumed to be primarily glycosaminoglycans, with a consequent change in water binding capacity and volume of the extracellular space.
Electron microscopic studies of the parathyroid gland of senile dogs
Authors: Setoguti Takao 
Published: February 2005

AbstractThe parathyroid gland of healthy senile dogs aged 8.5 to 15 years was compared with that of mature control dogs by examination with the electron microscope. Preparations fixed by perfusion with glutaraldehyde showed the cytoplasmic matrix of most parenchymal cells to be uniformly dense. None of the cells were of the extremely light type and dark cells were much less frequently noted than in preparations fixed by immersion in glutaraldehyde or osmium tetroxide. Syncytial cells and so‐called colloid follicles were more frequent in senile dogs than in control dogs. It was suggested that the content of the latter structures is not colloid but necrotic substance having origin from the parenchymal cells and that perhaps the occasional cells containing large, membrane‐bound inclusions may be degenerating cells which ultimately produce this necrotic substance. Oxyphil cells and mitochondria‐rich cells of another type were found in all senile dogs, but not in the controls. These cells, especially the mitochondria‐rich cells, frequently contained bizarre mitochondria that were modified in shape, size and arrangement. The most striking feature of these mitochondria was the concentric arrangement of elongated mitochondria which seemed to consist of densely layered cup‐shaped mitochondria. Such mitochondria were noted in all senile dogs aged ten years and over. The significance of mitochondrial pleomorphism in the parathyroid gland of senile dogs was discussed.
Freeze‐fracture study of the carotid body
Authors: Hansen John T. 
Published: February 2005

AbstractReplicas of freeze‐fractured rat carotid body chief (Type I) cells reveal the normal complement of cytoplasmic organelles. En face fractures of the chief cell plasmalemma exhibit occasional sites of fusion of the amine‐containing vesicles which characterize the carotid body. The endothelial cells lining the capillary network of the carotid body display numerous pinocytotic vesicles often oriented in linear arrays, and occasional fenestrae. The endothelial cells are joined together by tight junctions which appear as grooves (B face) forming a continuous network over the membrane.
The ultrastructure of endocrine cells in the corpus of the stomach of human fetuses
Authors: De Lemos Carmen 
Published: February 2005

AbstractThe ultrastructural development of endocrine cells from the corpus of fetal human stomachs is described. Samples were taken from fetuses ranging in fertilization age from 6–8 to 22 weeks.The identifying features used for the classification of the various types of endocrine cells were their basal location in the epithelium, the presence and morphology of their characteristic granules and the sizes of the mitochondria. Five types of endocrine cells with specific granules were found: D, EC, ECL, AL and D1. The type and number of endocrine cells increased as development proceeded. The endocrine cells were confined to the epithelium, they did not reach the lumen and they appeared to develop in situ. The D, EC and ECL cells were the most numerous. The fetal endocrine cells resembled morphologically those found in the stomachs of various adult animals. The EC, ECL and D1 cells contained small slender mitochondria with few cristae. Intramitochondrial granules were absent in all the cell types. Agranular electron‐lucent cells with small mitochondria were considered to be immature endocrine cells.The advanced stage of differentiation observed in these cells suggests that they may be capable of producing and storing biogenic amines and polypeptide hormones. Their possible involvement in the synthesis of serotonin, enteroglucagon and intrinsic factor is discussed.
The surface characteristics of the plasma membrane of the exocrine pancreas
Authors: Katsuyama T. , Spicer S. S. 
Published: February 2005

AbstractRegional differentiation of the plasma membrane and related structures of the exocrine pancreas has been studied ultrastructurally and cytochemically. Fixation with an osmium tetroxide‐silver acetate solution produced abundant fine precipitates on the luminal and basal surface of the centroacinar but not the acinar cells. Staining with dialyzed iron (DI) revealed the heaviest concentration of anionic sites on the luminal plasma membrane of the acinar cells, including the surface of both the intercellular canaliculi and the main lumen. The reactive sites on the apical acinar plasmalemma appeared to consist of discrete globules. DI‐reactivity of the lateral basal membranes was most prominent in the centroacinar cells and essentially absent in the acinar cells but was weak relative to that of the acinar‐cell apical plasmalemma. The lamina lucida of the basement membrane of the duct stained with DI, but that of basement membrane under acinar cells did not. Sialidase digestion prior to DI staining abolished the staining of plasma membranes. These results indicate that duct epithelial cells, including most prominently the centroacinar cells, are chiefly responsible for electrolyte and fluid transport.
The caudal luminous organs of lanternfishes: General innervation and ultrastructure
Authors: Anctil Michel , Case James F. 
Published: February 2005

AbstractNeuroanatomical, light and electron microscopic investigations of the caudal luminous organs of two lanternfish species, Stenobrachius leucopsarus and Parvilux ingens, were coducted in a search for morphological correlates underlying their luminescent behavior and control mechanisms. Complex neural pathways involving the spinal nerves and the sympathetic nerve chain of the caudal peduncle are associated with profuse segmental innervation to both the supracaudal and infracaudal organs. Neural composition of these segmental subunits indicates that pre‐ganglionic (spinal) as well as post‐ganglionic (sympathetic) fibers are involved in the neural control of luminescence of these organs. Neuro‐photocyte units, in which multiple nerve branches are sandwiched between two lamellar photocytes and establish large surface areas of close apposition, as well as gap junctions apparently interconnecting all photocytes throughout the luminous organs, may account for the very rapid and simultaneous displays of spontaneous or electrically driven luminescence. The organization of the caudal luminous organs is compared with that of lanternfish photophores. Relatively few granular and agranular synaptic vesicles are present in some nerve processes of the photocyte units, suggesting that adrenergic neurotransmission as well as electrotonic spread of excitation may be involved at the neuro‐photocyte junctions.
Innervation of myocardial microcirculation; terminal autonomic axons associated with capillaries and postcapillary venules in mouse heart
Authors: Forbes M. S. , Rennels M. L. , Nelson E. 
Published: February 2005

AbstractEfferent terminal axons are associated with numerous capillaries and postcapillary venules in both the atria and ventricles of mouse heart. These axons possess ultrastructurai characteristics which are typical of peripheral autonomic fibers in other tissues. Many are found near pericytes, in a relationship closely resembling that between terminal axons and smooth muscle cells of larger vessels. To demonstrate adrenergic terminals, mice were pretreated with 5‐ or 6‐hydroxydopamine; examination of these animals' hearts revealed that both adrenergic and cholinergic axons terminate near pericytes and endothelial cells. The results of this study are consistent with the view that there may be a functional innervation of capillaries and postcapillary venules of the mouse heart.
The fenestrated collar of mammalian cardiac sarcoplasmic reticulum: A freeze‐fracture study
Authors: Van Winkle W. B. 
Published: February 2005

AbstractFreeze‐fracture studies of papillary muscles from cat, rabbit and dog reveal the presence of a fenestrated collar of the sarcoplasmic reticulum (SR) in the region of the M band. This membrane specialization is structurally similar to that observed previously in skeletal muscle. This report includes mammalian cardiac muscle on the list of those muscles containing this SR membrane structure.
Immunocytochemical localization of a gastric inhibitory polypeptide‐like material within A‐cells of the endocrine pancreas
Authors: Smith Phillip H. , Merchant Frederick W. , Johnson David G. , Fujimoto Wilfred Y. , Williams Robert H. 
Published: February 2005

AbstractIn rat pancreatic islets, the glucagon‐producing A‐cells also contain a GIP‐like material as revealed by the peroxidaseantiperoxidase immunocytochemical technique. Control studies showed that this dual staining was not due to the cross‐reactivity of anti‐GIP with glucagon. It is concluded either that the A‐cells synthesize a GIP‐like peptide or that it is taken up from the circulation.
Glial cells in the earthworm ventral nerve cord make an A‐type nexus
Authors: Kensler Robert W. , Brink Peter , Dewey Maynard M. 
Published: February 2005

AbstractNexuses have been demonstrated between glial cell processes in the earthworm ventral nerve cord. The nexuses have been demonstrated by freeze‐cleavage to be A‐type nexuses, thus demonstrating for the first time the type of nexus present in the Annelida. If the nexal cleavage pattern has physiological significance then the results suggest that physiologically the nexuses of the earthworm may be similar to those of vertebrates.
The perineural sheath in the urodele amphibian
Authors: Krishnan N. , Singer Jon F. , Singer Marcus 
Published: February 2005

AbstractThe perineural epithelial cells of the peripheral nerve sheath in Triturus are elongated flat cells with long and thin cytoplasmic processes. Structural characteristics of the processes include a relative absence of common cytoplasmic organelles of the periniuclear cytoplasm but an abundance of vesicular profiles similar to fully formed pinocytotic vesicles. Unlike pinocytotic vesicles, vesicles of the processes often contain an 8‐nm thick filament attached to their cytoplasmic face. Vesicles are also interconnected by similar filaments or by tubules. In addition, almost all vesicles appear to have openings at the cell surface, a feature not seen for pinocytotic vesicles. The concentration of exogenous peroxidase in the vesicles, and the subsequent appearance of peroxidase in the endoneural fluid, myelin sheath and axon, support the notion that the vesicles function in the exchange of substances between extraneural and endoneural fluids.