bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genesis, ultrastructure and cytochemical study of the cat eosinophil
Authors: Presentey B. , Jerushalmy Z. , Ben‐Bassat M. , Perk K. 
Published: February 2005

AbstractEosinophils from cat bone marrow and peripheral blood were studied by electron microscopy and cytochemical procedures. The maturation of eosinophils and formation of typical granules were described. Contrary to the accepted opinion that the core of animal's eosinophilic specific granules have a crystal‐like structure, our observations revealed that the core has a myelin‐like cylindrical appearance, whose layered formation proceeds from the inside outwards.Electron microscopic observations revealed that localization of reaction product to potassium pyroantimonate and phosphotungstic acid and to acid phosphatase activity was similar to that of eosinophils of man and other animals. Antimonate deposits and acid phosphatase activity were detected between the layers of the myelin‐like structure of the core. Eosinophil granules failed to yield a positive reaction for peroxidase activity. The secretory activity of the eosinophil is discussed.
A freeze‐fracture study of intercellular junctions between various kinds of epithelial cells surrounding common endolymphatic space in the hearing organ of the chick
Authors: Hirokawa Nobutaka 
Published: February 2005

AbstractIntercellular junctions between various epithelial cells in the hearing organ (basilar papilla) of the chick were studied with the freeze‐fracture technique. The effects of hypertonic solutions on the intercellular junctions were also examined.The basilar papilla of the chick is primarily composed of hair cells and supporting cells in the neuroepithelium, specialized columnar cells (TMC) which attach to the tectorial membrane, and light cells (LC) and dark cells (DC) in the tegmentum vasculosum. All of these epithelial cells surround a common endolymphatic space. The tight junctions between hair and supporting cells, and those between adjacent supporting cells in the neuroepithelium are 0.1–0.3 μm in depth and display the usual network of branching and anastomosing strands of shared intramembrane proteins. The tight junctions in the tegmentum vasculosum have the same structure as in the neuroepithelium. In contrast, the tight junctions between the TMCs are extremely well developed: They are 1–2 μm in depth. In freeze‐fracture replicas, they appear as a fingerprint pattern of unbranched parallel particulate strands, running both parallel and perpendicular to the cell surface. After exposure to hypertonic solutions, all the epithelial cells are shrunken and intercellular spaces are expanded; all tight junctions, however, are intact.Thus, tight junctions in the basilar papillae are resistant to dissociation by hypertonic solutions. The usual zonulae occuludentes in the neuropithelium and tegmentum vasculosum are thought to prevent diffusion of endolymph through the intercellular spaces of epithelial cells. However, the tight junctions on the TMCs may function not only as a diffusion barrier, but also provide structural support to the cells anchoring the tectorial membrane which receives mechanical forces induced by the vibration of the basilar membrane.Extensive gap junctions are found between all the supporting cells (supporting cells in the neuroepithelium, TMCs, and LCs in the tegmentum vasculosum) surrounding the endolymphatic space.
Effects of age and dietary restriction on the kidney glomeruli of mice: Observations by scanning electron microscopy
Authors: Johnson J. E. , Barrows C. H. 
Published: February 2005

AbstractA study was undertaken to examine, by scanning electron microscopy (SEM), the kidney glomeruli of control mice 1 mo, 10 mo, and 24 mo of age, as well as dietarily restricted mice 10 mo and 24 mo of age. One month old female C57BL/6J mice were offered one of the following: (1) a control diet containing 24% protein fed ad lib; (2) the control diet fed on alternate days (intermittently fed); or (3) a diet containing 4% protein fed ad lib. Animals were sacrificed, by aldehyde perfusion at 1 mo, 10 mo, and 24 mo of age. The kidneys were sliced and prepared for SEM.There was a significant age‐related increase in glomerular diameter and amount of microvilli on the podocyte surface (microvillus index). Although the diameters of the podocytes increased approximately 20% with age, these differences were not statistically significant. Feeding a 4% protein diet resulted in smaller diameters of glomeruli and podocytes as well as smaller microvilli indices as compared to those of control animals. Although similar differences were observed in the kidneys of intermittently fed animals, only the microvillus index was statistically significant. Therefore, dietary manipulations, which have been shown to increase life span, result in marked morphological differences when compared to control animals.
Modification of mitochondria‐rich cells in different ionic conditions: Changes in cell morphology and cell number in the skin of xenopus laevis
Authors: Ilic Vesna , Brown Dennis 
Published: February 2005

AbstractXenopus laevis were kept in salt water (1.25% NaCl), distilled water, or tapwater for a month. Compared to the animals kept in tap water, the number of mitochondria‐rich (MR) cells in the NaCl‐adapted animals was significantly reduced, while it was increased in those maintained in distilled water. In addition, the MR‐cells of NaCl‐adapted animals lost their slender flask shape and developed large deposits of glycogen. The alteration of this cell type in conditions of high or low salinity may reflect a role of MR‐cells in adaptation to different ionic environments.
Distribution and morphometric quantitation of pancreatic endocrine cell types in the frog, rana pipiens
Authors: Kaung Hue‐Lee Cheng , Elde Robert P. 
Published: February 2005

AbstractCells reactive to anti‐anglerfish insulin, anti‐porcine glucagon, anti‐synthetic somatostatin, and anti‐bovine pancreatic polypeptide were identified in adult Rana pipiens male pancreases using peroxidase anti‐peroxidase immunohistochemistry. Insulin positive cells are columnar shaped and arranged in cords. Glucagon positive and somatostatin positive cells are located around the core of insulin positive cells. Isolated cells and clusters of cells of only one cell type are also found. Adjacent sections stained with anti‐glucagon and anti‐bovine pancreatic polypeptide showed that glucagon positivity and pancreatic polypeptide positivity are found in the same cells. Comparison of double stained adjacent sections confirmed the presence of these two antigens in the same cells, and further showed the occasional presence of cells which are positive to only glucagon or pancreatic polypeptide. Staining of rat pancreas with these two antisera showed that glucagon and pancreatic polypeptide are present in two distinct cell populations.Morphometric quantitation of immunohistochemically stained sections of Rana pipiens pancreases showed that about 2% of the pancreas is endocrine tissue. Of this, 43% is compared of insulin positive cells, and 43% is occupied by glucagon‐pancreatic polypeptide positive cells. Somatostatin positive cells occupy about 14% of the total islet volume.The presence of glucagon and pancreatic polypeptide in the same cell population in the frog, but in different cell populations in mammals, may reflect special functional adaptation in this species, or a close relation of these two hormones and their cells of production during evolution.
Ultrastructural effects of riboflavin deficiency on rat hepatic mitochondria
Authors: Tandler Bernard , Hoppel Charles L. 
Published: February 2005

AbstractThe hepatic mitochondria of rats fed a riboflavin‐deficient diet were examined by electron microscopy. Discoidal mitochondria with elongated cristae increased in frequency from day 4 to day 12 of the test diet. At day 22, sheaves of closely packed cristae were present in many otherwise typical mitochondria. At day 53, numerous cupshaped mitochondria appeared; these often nested one inside the other. From this day onward, the mitochondria showed a tendency towards increasing size. By day 82, some had a diameter greater than 8 μm. These and other, smaller mitochondria often contained extremely prominent matrix granules. The production by riboflavin‐deficiency of giant mitochondria in the rat liver appears to be unrelated to their capacity to carry out oxidative metabolism.
Dynamic histomorphometry of alveolar bone remodeling in the adult rat
Authors: Vignery Agnes , Baron Roland 
Published: February 2005

AbstractAlveolar bone normally undergoes remodeling on one side of the socket and modeling on the opposite side as the tooth migrates at a rate of 6.7 μm per day. Periodontal ligament width, however, remains constant. Because of this very high turnover rate, this bone is a good model to study bone modeling and remodeling activities. This study was undertaken in order to measure the different cellular events occurring during tooth migration along the alveolar bone of the rat. The histomorphometric measurements performed on this model permitted us to calculate the duration of each phase of the remodeling cycle, i.e., resorption lasts about 1.5 days and reversal about 3.5 days. Since the duration of the forming phase is about 1 day (Guyomard and Baron, ′74), the total duration of each remodeling cycle is about 6 days. This time is very short compared to 60–120 days in adult human trabecular bone. Additionally, in this model each osteoclast resorbs 2–4 times its own volume of bone per day. Based on this knowledge, it will be possible to measure accurately the effects of experimental conditions on bone cells and bone remodeling in this rat alveolar bone model.
Deformities in the head region of late spermatids of hypophysectomized‐hormone‐treated rats
Authors: Russell Lonnie D. 
Published: February 2005

AbstractTestosterone capsules implanted in hypophysectomized rats prevented tubulobulbar complexes from forming in many late spermatids. These spermatids also displayed an accumulation of cytoplasm (swelling) in the perinuclear region of the head. Other spermatids with normal or near‐normal numbers of tubulobulbar complexes showed a typical perinuclear space. The results indicate, but do not prove, that development of tubulobulbar complexes (and their subsequent phagocytosis) is essential for the normal elimination of cytoplasm that takes place prior to sperm release.
Three‐dimensional electron microscopy of mitochondria and endoplasmic reticulum in the red muscle fiber of the rat diaphragm
Authors: Rambourg A. , Segretain D. 
Published: February 2005

AbstractThe three‐dimensional arrangement of mitochondria and endoplasmic reticulum in the red muscle fiber was studied both in thick sections of the rat diaphragm fixed in glutaraldehyde and impregnated with uranyl acetate followed by lead and copper citrate, and in thin sections of glutaraldehyde fixed tissue treated with ferrocyanide‐reduced osmium. The mitochondria were located either at the periphery of the fiber, where they were spherical, or between the myofibrils, where they formed longitudinal columns of rectangular, slightly flattened elements. From both types of mitochondria, thin, elongated branches arose at right angles that formed transversely oriented mitochondrial pairs at the I band level. At the periphery of the fiber, the endoplasmic reticulum took the appearance of a subsarcolemmal network of tubular cisternae oriented parallel to the cell surface. In the juxtanuclear region, it was made up of spherical masses composed of tightly knitted tubules that were interconnected by more loosely anastomosed tubules. In between the myofibrils, it was composed of longitudinally oriented repetitive units whose structure varied according to their position in front of the A or I bands of the myofibrils. In front of the A band, the endoplasmic reticulum appeared as a single sheet of anastomotic tubules compressed between the adjacent myofibrils, whereas at the I band level, its tubular elements passed in front and behind the transverse expansions of the mitochondria to form an intricate multilayered network in front of the Z line.
The stereoscanning electron microscopy and ultrastructural histochemistry of the avian and reptilian surfactant systems: Indian dove, desert spiny and taiwan golden skink lizards
Authors: Wetzstein H. Y. , Stratton C. J. , Olson N. 
Published: February 2005

AbstractLung tissues from the Indian dove, Scardafella inca, desert spiny lizard, Sceloporus magister, and the Taiwan golden skink lizard, Mabuya aurates, were studied by transmission electron microscopy utilizing ruthenium red as a carbohydrate stain and with the so‐called lipid‐carbohydrate retention procedures to elucidate the morphology of the surfactant systems. Stereoscopic scanning electron microscopic procedures were utilized for a comparative anatomical study of these three species, and the results were compared with the rat and frog in the companion article. The avian lung tissues demonstrated several peculiarities. The ciliated epithelial cells of the bronchus had cytoplasmic ciliated projections between the boundaries of mucus secreting cells. The discrete morphology of the main bronchus, secondary bronchi, parabronchi, and the air capillaries, and their three‐dimensional morphologic perspective were elucidated. The skink illustrated an arrangement of primary, secondary, and tertiary septa, with elaborate tertiary septal pits, similar to the amphibian. All septa contained a solid connective tissue core. The desert lizard was similar to the skink except the tertiary septal pits were rudimentary. All three species had a modified great alveolar pneumocyte and a laminated surfactant which included a carbohydrate matrix material between layered phospholipid‐based membranes. The ruthenium red additionally stained the homogeneous surface‐lining material. A comparative analysis of the surfactant systems of these three species with each other, and with the rodent and amphibian in the companion article, were discussed in terms of phylogenetic origin.
Intraepithelial asymmetric‐unit‐membrane plaques in mammalian urinary bladder
Authors: Alroy Joseph , Weinstein Ronald S. 
Published: February 2005

AbstractAsymmetric‐unit‐membrane (AUM) plaques are major components of the luminal surface of superficial cells in mammalian urinary bladder. We have now demonstrated ultrastructurally identical AUM plaques in intraepithelial locations, at the lateral and basal surfaces of superficial cells and at the apical surfaces of intermediate epithelial cells in the urinary bladder. Typically, luminal apposing AUM plaques are present in clusters. Similar plaque clusters are present on apposing surfaces of cell pairs within the epithelium. These intraepithelial plaque clusters are in register, although often separated by a wide interspace. In areas where they come into closer apposition, they form membrane complexes resembling but distinctly different from certain types of cell‐to‐cell junctions. Both luminal and intraepithelial AUM plaques serve as membrane attachment sites for cytoplasmic microfilaments. Their intraepithelial location and association with microfilaments support the hypothesis that AUM plaques serve a mechanical function and modulate cell surface area during the urinary bladder distention‐contraction cycle.
Intramedullary schwann cell development following x‐irradiation of mid‐thoracic and lumbosacral spinal cord levels in immature rats
Authors: Heard Jeanne K. , Gilmore Shirley Ann 
Published: February 2005

AbstractIntramedullary Schwann cells have been observed following x‐irradiation of lumbosacral spinal cords in immature rats. The present investigation was designed to determine whether or not the development of intramedullary Schwann cells within the spinal cord could be influenced by the portion of the spinal cord exposed to radiation. Three groups of rats were irradiated when three days of age. In one group the irradiated zone was limited to a 5 mm length of mid‐thoracic spinal cord (T only), in another group the irradiation was limited to a 5 mm length of lumbosacral spinal cord (L only), and in a third group 5 mm lengths of both mid‐thoracic and lumbosacral spinal cord (T/L) were irradiated. All of these animals received a single exposure to 4000 R of soft x‐rays (HVL 0.16 mm Al). Sham‐irradiated littermates served as control animals. Groups of rats were killed at intervals from 9 through 60 days following irradiation, and the spinal cords were prepared for light microscopic examination. Schwann cells appeared in the lateral portion of the lumbosacral dorsal funiculi of L only and T/L irradiated spinal cords as early as 9 days post‐irradiation. By 19 days post‐irradiation Schwann cells occupied the lateral, medial, and deep medial portions of the dorsal funiculi in the lumbosacral areas. By 25 days post‐irradiation Schwann cells were also observed in the dorsal gray horns. In contrast, Schwann cells were not observed in the midthoracic regions of T only and T/L irradiated rats until 11 days post‐irradiation. The accumulation of these cells was not extensive, and, in general, the Schwann cells were confined to the lateral portion of the dorsal funiculi in all animals. These findings indicate that intramedullary Schwann cell development is influenced by the region of spinal cord irradiated in immature rats.
Effects of estrogen and androgen on the ultrastructure of secretory granules and intercellular junctions in regressed canine prostate
Authors: Merk Frederick B. , Leav Irwin , Kwan Paul W. L. , Ofner Peter 
Published: February 2005

AbstractEpithelial cells in the prostate of the castrated or hypophysectomized dog were studied by thin‐section and freeze‐fracture electron microscopy to determine in vivo responses to estradiol‐17β 17‐cyclopentylpropionate (ECP) and testosterone cyclopentylpropionate (TCP). Particular attention was given to changes in specific organelles and intercellular junctions that might reflect hormone action. The few secretory granules that remain in the regressed epithelium (vestigial granules) serve as markers of prior androgen responsiveness. Pharmacologic doses of ECP caused regressed glandular cells to acquire a novel phenotype. Characteristic features of these estrogen‐modified glandular (EMG) cells are newly formed secretory granules and tonofilament bundles that coexist with vestigial granules, thus demonstrating bipotentiality of response. Glandular cell‐tight junctions appear unaltered by the endocrine manipulations. Although EMG cells have squamous cell features, tight junctions remain intact. Desmosomes in the canine prostate are dimorphic and are classified 70F and 100F according to the width of the filaments that converge on the dense plaques. In intact dogs, 100F desmosomes are associated with basal‐reserve cells, whereas only the 70F variety is found between glandular cells. TCP treatment does not alter this distribution. Following ECP administration, both 70F and 100F desmosomes are present between EMG cells. The coexistence of newly formed secretory granules and tonofilaments of 100F desmosomes in the same EMG cell represents estrogen‐induced bidirectional differentiation. Our findings indicate that androgens and estrogens are individually capable of controlling the expression of secretory granules and desmosomes. In intact animals, male and female sex hormones may act in concert to direct epithelial cell differentiation of the prostate.
Electron microscopy of terminal buds on the barbels of the silurid fish, Corydoras paleatus
Authors: Fujimoto Sunao , Yamamoto Koji 
Published: February 2005

AbstractThe terminal buds of the Corydoras paleatus were observed with the electron microscope. Almost all the cells constituting the buds can be classified into two distinct cell types, supporting and receptor cells. In addition, a few cells designated as basal cells exist in the bottom of the buds and appear to be an immature form of each distinct cell type in the course of cell renewal.The receptor cells are characterized by the presence of tubules extending from the apical process. By the application of lanthanum nitrate as an extracellular marker, we demonstrated that the tubular system is in continuity with the extracellular space.The data suggest that the tubular system represents an amplification of the apical cell surface as a particular site of chemoreceptive activities, although we do not rule out a role for active absorptions of ions in a very hypotonic environment.
Acrosomal and nuclear morphogenesis in ram spermatids: An experimental study of hypophysectomized and testosterone‐supplemented animals
Authors: Courtens J. L. , Courot M. 
Published: February 2005

AbstractAn ultrastructural study of spermiogenesis was carried out in adult hypophysectomized rams supplemented with testosterone at a dose which induced a normal or excessive (1 to 3) concentration of the steroid within the rete testis fluid (Monet‐Kuntz et al., '76). Most of the spermatids from 15‐ or 20‐day treated animals displayed a normal nuclear appearance but possessed acrosomes with morphological abnormalities. The process of acrosome formation as well as its binding to the nucleus was severely impaired in young spermatids, whereas only morphological changes of the acrosomes were seen in old spermatids. The suggestion is made that acrosome development is under the control of endocrine‐dependent cellular events occurring before the beginning of spermiogenesis, possibly via Sertoli cell/germ cell interactions. The spermatids from hypophysectomized rams supplemented with testosterone for 40 days were normal in appearance but reduced in number. The Sertoli cell ultrastructure differed for the two durations of treatment.
Immunocytochemical analysis of prolactin production by monolayer cultures of GH3 rat anterior pituitary tumor cells: I. Long‐term effects of stimulation with thyrotropin‐releasing hormone (TRH)
Authors: Hoyt Richard F. , Tashjian Armen H. 
Published: February 2005

AbstractThyrotropin‐releasing hormone (TRH) stimulates prolactin production in cultured GH3 rat anterior pituitary tumor cells. For correlation of cell‐by‐cell prolactin distribution and intracellular hormone concentration, GH3 cells were grown to plateau‐phase density on glass coverslips in plastic dishes. Acetone‐fixed, cell‐bearing coverslips were stained for prolactin by an immunoglobulin‐peroxidase bridge technique (Mason et al., '69); cells on the plastic dishes were assayed for prolactin (microcomplement fixation immunoassay, Tashjian, '73) and protein content. Intracellular prolactin, unaffected quantitatively by acetone fixation and choice of substratum, was localized immunocytochemically by a granular brown precipitate, abolished if anti‐prolactin serum was preabsorbed with rat prolactin or omitted from the protocol. Intracellular prolactin was maximized with colchicine (5.0 × 10−6 M; final 3 hr of incubation) in control and TRH‐treated (10 ng/ml; 48 hr) GH3 cell cultures. A total of 8,500 cells were classified by light microscopy as unstained, heavily (H) or moderately (M) stained for prolactin. In controls, 35% of cells were prolactin‐positive: 6% H and 29% M. After TRH, 45% were positive: 7% H and 38% M. Although prolactin‐positive cells were unevenly distributed, comprising 25% to 46% of cells in individual microscopic fields in controls, TRH increased the proportion of M cells in all areas. TRH treatment raised prolactin levels to 450% of control, but mathematical analysis attributed less than 30% of the increase to new prolactin‐positive cells. We conclude that TRH acts on GH3 cultures principally by raising the mean hormone content of individual positive cells rather than by increasing the proportion of cells committed to prolactin production.