bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlation between structure and glycogen content of livers from rats on a controlled feeding schedule
Authors: Cardell Robert R. , Larner Joseph , Babcock Muriel B. 
Published: February 2005

AbstractMale rats were maintained on a controlled feeding schedule and groups of animals sacrificed at 2, 15, 21, 36, 48 and 72 hours of fasting. Chemical determinations of glycogen showed that livers of rats fasted two hours contained 8.7% glycogen; 15 hours, 6.2%; 21 hours, 0.7%; 36 hours, 0.7%; 48 hours, 0.8%; and 72 hours, 0.4%. After PA/S procedures, glycogen appeared in hepatocytes of rats fasted 2 and 15 hours as large masses intensely stained. At these time‐periods, almost all cells contained significant quantities of glycogen but hepatocytes located toward portal tracts showed larger and more intensely stained masses of glycogen than found in cells near central veins. After longer periods of fasting, glycogen masses decreased in size, number, and staining intensity. The fine structure of hepatocytes from rats fasted 2 or 15 hours showed abundant α and β particles of glycogen in the form of large masses throughout the cytosome. These correlated in position and shape to the masses of glycogen seen in the light microscope. As glycogen depletion occurred (fasted 21 hours and longer) the number of glycogen particles decreased in hepatocytes. It is concluded from this study that a good correlation exists between chemical determinations of hepatic glycogen, cytochemistry of glycogen in hepatocytes, fine structure of liver cells, and the fasting state of the animal.
Adrenergic innervation of the rat submandibular and parotid glands. An electron microscopic autoradiographic study of the uptake of tritiated norepinephrine
Authors: Bogart Bruce Ian , De Lemos Carmen L. 
Published: February 2005

AbstractThe adrenergic innervation of the rat submandibular and parotid glands was investigated by monitoring the uptake of H3‐NE by nerve terminals with electron microscopic autoradiographic techniques. Both glands contained nerve bundles in the stroma encompassed by a Schwann cell sheath. Silver grains due to H3‐NE were observed overlying several nerve terminals found in these nerve bundles, while other nerve terminals in the same bundle were devoid of silver grains. In the submandibular gland, adrenergic nerve terminals characterized by silver grains due to H3‐NE were observed in the stroma in close relationship to, but not in direct apposition to parenchymal cells. In the parotid gland, silver grains due to H3‐NE were observed overlying nerve terminals contained within the basement lamina and in close contact with acinar cells.
Rat renal capsule: Presence of layers of unique squamous cells
Authors: Bulger Ruth Ellen 
Published: February 2005

AbstractUnique squamous cells forming one or more layers are invariably present at the inner border of the rat kidney capsule. The cells frequently surround a space or lumen of irregular contour. The cells appear to be supported by collagenous bundles which run between adjacent cells within groove‐like indentations in a single cell, but the connective tissue components are separated from the squamous cells by a thick basal lamina. The fibrous capsule is bound to the renal parenchyma by loose connective tissue containing fibrocytes, small collagen bundles, and abundant mononuclear cells which are partially surrounded by processes of the fibrocytes.
Fine structure of the ultimobranchial body of the chick
Authors: Isler H. 
Published: February 2005

AbstractThe ultimobranchial bodies of the chick consisted of follicles and cell cords. The follicles were of various sizes and shapes. Their epithelium was simple or stratified, squamous to cuboidal, and contained two cell types. The lumen‐bordering cells had microvilli at their apex, a few long, flat ergastoplasmic sacs, a prominent Golgi, an extensive system of smooth membrane tubules and microvesicles, abundant free ribosomes, no granules and indented nuclei. Their lateral membranes followed a sinuous path and their membrane at the base showed occasional intense pinocytotic activity. Thus these cells appear well differentiated and functionally active, whatever their function may be. The second cell type, never in contact with the lumen, also differed by its abundant granules, the smooth path of its plasma membrane, the smooth outline of its nucleus and the occasional presence of intranuclear vesicles. The cell cords were made essentially of these same granular cells. It was shown histoimmunologically that numerous calcitonin‐containing cells were present in the cell cords; those few present within the wall of the vesicles never bordered on the lumen. It is concluded that the granular cells are producing calcitonin, while the lumen‐bordering cells contribute the holocrine secretion of the vesicle.
Peristaltic contractions of the murine urogenital sinus
Authors: Cunha Gerald R. 
Published: February 2005

AbstractUrogenital sinuses from 14‐ to 17‐day old embryonic mice were grown in vitro for six days. Fourteen‐day old urogenital sinuses exhibited weak, irregular peristaltic contractions, while in explants from 15‐ to 17‐day old embryos peristaltic contractions were forceful and regular in rhythm. Neither testosterone dipropionate nor Cyproterone acetate substantially influenced contractile activity whereas estradiol was slightly inhibitory. Exposure to cytochalasin‐B resulted in a complete, but reversible inhibition of peristalsis. The initiation of peristaltic contractions correlated well in time with the presumed onset of urine production by the developing kidneys, and it is suggested that these peristaltic contractions may facilitate urine transport from the kndneys to the amnionic cavity.
Stimulation of acinar cell proliferation by isoproterenol in the postnatal rat submandibular gland
Authors: Chang W. W. L. , Barka T. 
Published: February 2005

AbstractDuring the postnatal development of the submandibular gland, the stimulation of DNA synthesis and mitosis by a single injection of isoproterenol, measured as the percentage of labeled cells in radioautographs, was dependent on the age of the rat. The drug had no effect on the proliferative activity in two day old rats, but stimulated DNA synthesis in older (7–42 day old) animals. In general, the degree of stimulation was directly related to the proportion of acinar cells and inversely related to the proliferative activity in the gland of control rats. An analysis of various cell types revealed that the stimulation of DNA synthesis in the gland was essentially restricted to the acinar cells in rats older than 14 days of age. In seven day old rats, the acinar cells were not stimulated, but their precursors, the proacinar cells, the terminal tubule cells and the intercalated duct cells were stimulated to synthesize DNA by isoproterenol. This suggested that isoproterenol had an effect on the transformation of precursor cells to acinar cells.
Enhanced mineralization of the tibial epiphyseal plate in the rat following propylthiouracil treatment: A histochemical, light, and electron microscopic study
Authors: Dearden Lyle C. 
Published: February 2005

AbstractFollowing treatment with propylthiouracil, most chondrocytes in the reserve and upper proliferation zones in the tibial epiphyseal plate exhibit degenerate ultrastructural morphology. In the extracellular matrix, sulfated mucopolysaccharide is reduced, matrix vesicles are increased both in number and in size, apatite crystals are present in all zones, and mineralization is enhanced.In post‐treatment recovery, chondrocyte degeneration decreases; however, the extracellular matrix is considerably delayed in returning to conditions comparable to those in corresponding controls and this is indicated by the continued presence of apatite crystals in abnormal locations.Chondrocyte degeneration, sulfated mucopolysaccharide, and matrix vesicles, are discussed as they relate to the mineralization process.
Lactic dehydrogenase activity in the hair follicles of the stump‐tailed macaque (Macaca speciosa)
Authors: Sasai Yoichiro 
Published: February 2005

AbstractLactic dehydrogenase activity was studied in hair follicles from both the bald and hairy regions of the scalp of the stump‐tailed macaque by the application of the method of Lineweaver‐Burk to the histochemistry. There was no difference between terminal and vellus follicles in total lactic dehydrogenase activity. During anagen, the activity was higher in the lower part of the external sheath and was similar to that in the bulbar sac. The activity of the heart‐type lactic dehydrogenase (H‐LDH) was high in the matrix, whereas that of the muscle‐type lactic dehydrogenase (M‐LDH) was high in the external sheath of the lower and upper bulb portions. The activity of M‐LDH in the matrix of terminal hair follicles was extremely low compared with that in vellus follicles. In telogen, however, there was no difference between the two types of follicles.
Cytochemical studies of the maternal surface of the syncytiotrophoblast of human early and term placenta
Authors: Martin B. J. , Spicer S. S. , Smythe N. M. 
Published: February 2005

AbstractLight microscopic studies using a battery of basic dye stains combined with sialidase and hyaluronidase digestions indicated that the extensive basophilia of the maternal surface of the placental syncytium largely results from the presence of a non‐sulfated mucosubstance specifically identified as hyaluronic acid. Ultrastructural examination of dialyzed iron (DI) stained specimens revealed that DI‐positive filaments observed along the syncytial surface were removed by hyaluronidase digestion. Staining with the lectins, Concanavalin A or lentil bean hemagglutinin produced an intense and periodic pattern of staining that was not enzyme labile. Incubation of tissue sections in the enzyme solutions or control buffers allowed the lectins to penetrate the syncytial plasma membrane and stain material within the endoplasmic reticulum presumed to be human chorionic gonadotropin. The maternal surface exhibited essentially no reactivity for acid phosphatase but showed strong alkaline phosphatase activity with a periodic staining pattern. With each of the techniques used there was variability in the intensity of staining in different regions along the maternal surface, suggesting that functionally different zones may be identified cytochemically. Only minor differences were observed in the cytochemical reactivity of early compared with term placenta.
Fine structure of myogenesis and elastogenesis in the developing rat lung
Authors: Collet A. J. , Biens G. Des 
Published: February 2005

AbstractThe processes of myogenesis and elastogenesis are studied under the electron microscope in developing rat lungs, throughout the 15th to the 21st days of the gestation period. Myogenesis follows bronchial development and stops at the beginning of the alveolar zone, at the primitive respiratory bronchiole level. Elastogenesis appears at the periphery of the myoblasts during their differentiation. Thin myofilaments only are observed within myoblasts and their formation precedes that of dense bodies.Primitive respiratory bronchioles are visible on the 19th day and are characterized by an early elastogenesis carried out by fibroblasts. At this stage there are no elastic fibers around the alveolar tubules. Then (20th and 21st days) elastogenesis spreads throughout the alveolar zone, accompanying the alveolization process. Peculiar morphological characteristics of the pulmonary fibroblast are underlined. In relation to both muscular cells and fibroblasts the fine structural features of the rat pulmonary elastogenesis are identical to those previously described in other organs. Myoblasts and fibroblasts probably originate from the same primitive mesenchymal cell. Their differentiation depends on the zone where they are located. The relations between connective tissue and epithelial cell differentiation suggest a control of lung development by means of reciprocal induction processes.
An electron microscopic investigation of the surface coat of visceral yolk sac endoderm cells in the guinea pig
Authors: King Barry F. 
Published: February 2005

AbstractGuinea pig visceral yolk sac endoderm cells are known to absorb proteins from the uterine lumen by the process of pinocytosis. Since previous studies have shown that the first step in protein absorption is the binding of the protein to an extracellular material on the surface of pinocytotic invaginations, it was thought that the surface coat might possess receptor sites for molecules which are subsequently absorbed. This study investigates the nature of the surface coat of the endoderm cells using ruthenium red, alcian blue/cetylpyridynium chloride‐lanthanum and concanavalin A‐peroxidase procedures. Results using these methods showed the presence of a surface coat on both the microvilli and pinocytotic invaginations. The coat on the pinocytotic invaginations was thicker than that on the microvilli. Concanavalin A receptor sites were separated from one another on the cell surface. Since only those pinocytotic invaginations which were open to the surface at the time of fixation would be “stained” by these methods, the procedures also show that the numerous tubules and vesicles in the apical cytoplasm do not all form an intercommunicating labyrinth open to the surface, even though most of them are part of a related functional system. The results indicate that the surface coat contains mucopolysaccharide components. In addition, concanavalin A receptor sites are present which are probably oligosaccharides associated with a glycoprotein component of the apical cell membrane.
A new fixation technique for the electron microscopic study of pulmonary surfactant
Authors: Callas Gerald 
Published: February 2005

AbstractPreviously reported methods for the electron microscopic visualization of the surface layer (surfactant) of the alveolar lining cells have proved less than ideal and further development in this area is needed. Two percent agar in glutaraldehyde injected into the respiratory tree concurrently with vascular perfusion seems to offer some real advantage over techniques described by others. The combination of glutaraldehyde and agar acts both as an obstruction that holds surfactant against the alveolar surface and as a fixative due to the buffered glutaraldehyde component. This technique offers more consistent results and more extensive demonstration of the surfactant layer over the alveolar surface.
The fine structure and innervation of the cushion veins of the human nasal respiratory mucosa
Authors: Cauna Nikolajs , Cauna Dzidra 
Published: February 2005

AbstractCushion veins of the human nasal lining were studied in eight patients of both sexes ranging in age from 11 to 59 years. It was found that the subendothelial cushions were part of the tunica media and consisted of smooth muscle cells, collagen and elastic fibers and occasional fibrocytes. The muscle fibers of the cushion nearest to the endothelium were circular. They extended processes towards the endothelium through gaps in the endothelial basement membrane and formed appositional junctions with the endothelial cells. The rest of the cushion consisted of longitudinal muscle fibers. The sarcoplasm of the muscle cells was characterized by large areas filled with vesicles of various sizes. In addition, these cells possessed cytoplasmic processes which were devoid of a basement membrane and which did not show the regular structure of sarcoplasm. The subendothelial cushion possessed a rich, intrinsic nerve supply of adrenergic and cholinergic axons. It is suggested that the cushion veins regulate the drainage of the cavernous tissue and are under nervous and humoral control. The increase in girth of the subendothelial cushion is effected by contraction of the longitudinal muscle cells and probably by uptake of extracellular fluid by means of the specialized cytoplasmic processes. The single layer of circular muscle cells situated between the endothelial lining and the longitudinal musculature, may provide protection to the endothelium against distension when the cushion expands.
Junctional complexes in the preimplantation rabbit embryo
Authors: Hastings Richard A. , Enders Allen C. 
Published: February 2005

AbstractThe morphology and development of junctional complexes between blastomeres of the preimplantation rabbit embryo were investigated using several approaches. Electron microscopic examination of embryos stained en bloc with uranyl acetate, and the study of junction permeability using horseradish peroxidase and lanthanum nitrate provided information on structure, intermembrane spacing and permeability of the junctional complexes. In addition, the freeze fracture technique was used with day 5 and day 6 blastocysts, since the large size of these embryos facilitated use of this method. These experiments showed that although rudimentary junctions were present between blastomeres of the early cleavage stages, effective tight junctions were not present until the blastocyst stage. Electron microscopic examination of thin sections revealed apical foci of membrane approximation or “fusion” between trophoblast cells by day 4. Freeze fracturing revealed a lattice of interconnecting ridges (on the A face) and grooves (on the B face) in the apical region between trophoblast cells of the day 5 blastocyst. This lattice formed a continuous band along the apical margin of each cell, and therefore constituted a zonula occludens. The zonula occludens of the day 5 blastocyst averaged 2–3 ridges per lattice, while day 6 blastocysts had lattices that averaged 5–6 ridges. Also seen in the freeze fracture replicas from the day 5 and day 6 blastocysts were local accumulations of intramembranous particles on the A face. These particles were often observed in aggregates similar to those of previously described gap junctions. It could not be determined whether these small regions of particles were true gap junctions or a possible primitive form of gap junction because the complementary pitted surfaces (B face pits) were not demonstrated.
Alterations in the fine structure of hepatocytes in hyperthyroid rats
Authors: Callas Gerald , Cannon M. Samuel 
Published: February 2005

AbstractUltrastructural investigation of liver from ten radiothyridectomized adult male albino rats, made hyperthyroid by administration of desiccated thyroid for eight to ten weeks, revealed changes in hepatic organelles, but no differences between centrilobular, midzonal and periportal hepatocytes of a single lobule. The mitochondria were enlarged with an increase in matrix density, but no increase in number of mitochondria or alterations in membranes or criste was observed. The smooth endoplasmic reticulum appeared slightly increased and dilated in treated rats, while stacked cisternae of the rough endoplasmic reticulum were seldom seen. Large vacuoles, which often contained follicular material and frequently opened into the spaces of Disse, were observed at the periphery of hepatocytes. The vacuoles may arise from invaginations of the cell membrane along these spaces to increase the surface area and to act as channels for liver metabolites. Moreover, in hyperthyroid rats hepatic glycogen was uniformly depleted. Whether these changes were a primary effect of thyroid hormone or secondary to metabolic alterations is unclear.
The variable fine structure of elastin visualized with verhoeff's iron hematoxylin
Authors: Brissie R. M. , Spicer S. S. , Thompson N. T. 
Published: February 2005

AbstractVerhoeff's iron hematoxylin (VIH) followed by lead citrate (LC) applied to epoxy thin sections stained the dense component of elastic fibers heavily and the peripheral microfibrillar component lightly in guinea pig trachea and mouse testis fixed with a glutaraldehyde‐osmium tetroxide sequence. This method stained large fimbriated fibers beneath tracheal epithelium, small fibers and stacked aggregates thereof in the deep lamina propria, cartilage and adventitia of the trachea and large stacked fibers in the fibroelastic band of the trachea. Fibers of the fetus differed from those of the adult, especially in the subepithelial elastic lamina of the trachea. Elastic fibers were intimately associated with fibroblasts and particularly slender fibroblast processes in tracheal stroma and with chondrocytes in tracheal cartilage. Fibroblasts associated with elastic fibers in the tracheal subepithelial lamina propria were often closely bordered by eosinophils, mast cells, or monocytes. Occasional mast cells extended slender processes around elastic fibers in the subepithelial lamina propria. In mouse testis and in many regions of the trachea, small elastic fibers were identified which were below the limits of resolution for the light microscope and were not apparent at the ultrastructural level in routinely stained thin sections.
Ultrastructural and histochemical study of the adrenal medulla in normal and cold‐stressed syrian hamsters
Authors: Al‐Lami Fadhil , Farman Naziha 
Published: February 2005

AbstractThe effect of 24 and 48 hours' cold stress on the hamsters' adrenomedullary follicles and on the medullary ATPase activity was studied by light and electron microscopy. Only norepinephrine cells were depleted after this stress, and exocytosis seemed to be the mechanism involved in the release of catecholamine. Follicles containing these cells expanded and their lumina became narrow. A few other cellular and follicular changes also occurred and are described.ATPase activity was apparent in control organs along the endothelial linings, in neural elements and macrophages, and in approximately 40% of the linings of follicular lumina. Cold stress did not alter this pattern.These results have been compared with previous findings and the possible functions of the follicular lumina are discussed. It is concluded that they are unlikely sites for catecholamine storage or release.
Localization of cells retaining 3H‐estradiol in the forebrain of rabbits
Authors: Anderson Conwell H. 
Published: February 2005

AbstractOvariectomized rabbits received 3H‐estradiol via an ear vein and were killed one hour later. Autoradiograms were prepared and exposed up to six months. Labeled cells, as indicated by many silver grains over the nucleus of a neuron, were found in many nuclei of the brain. Thus, the bed nucleus of the stria terminalis had labeled cell bodies. The stria terminalis leads into the medial preoptic area where great numbers of cells concentrated the estrogen. Farther into the hypothalamus the labeled cells were numerous in the ventromedial and arcuate nuclei. Other locations with labeled cells were the lateral septal nucleus and nucleus accumbens septi, the periventricular preoptic nucleus, anterior hypothalamic nucleus, nucleus supraopticus diffusus, posterior hypothalamic nucleus, and premammillary nucleus. The labeled cells could be followed into the central gray surrounding the aqueduct of Sylvius. The amygdaloid nuclei, and in particular the medial amygdaloid nucleus, had labeled cells as did the most ventral posterior part of the hippocampal cortex. The results are discussed in comparison with those in the rat, and with reference to physiologic data.