bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunocytochemical analysis of prolactin production by monolayer cultures of GH3 rat anterior pituitary tumor cells: II. Variation in prolactin content of individual cell colonies, and dynamics of stimulation with thyrotropin‐releasing hormone (TRH)
Authors: Hoyt Richard F. , Tashjian Armen H. 
Published: February 2005

AbstractThe preceeding report (Hoyt and Tashjian, '80) correlates immunocytochemical localizations and mean prolactin concentrations in GH3 monolayers maximally stimulated with TRH; the present does so over the duration of TRH treatment. Low density seeding produced numerous discrete GH3 cell colonies. Cultures were harvested ½, 4, 12, 24, 72, and 144 hr after administration of TRH (50 ng/ml) or saline (control). All cells (42,658 total) in at least 10 microscopic fields/monolayer, 1 cell colony/field, were classed as unstained, heavily (H), moderately (M), or weakly (W) stained for prolactin. In controls, colonies contained 51‐91 prolactin‐positive cells/100 of population. Colonies with few positive cells had many more W than M cells, and the reverse was true in those with many positive cells. In all colonies, the effect of TRH was biphasic. Initial (0‐4 hr) release of prolactin was overlapped, beginning at 3‐4 hr, by a progressive increase of intracellular hormone. After 144 hr, the prolactin content of treated cultures had increased to 190% of control, and prolactin‐positive cells were more numerous (114% of control). These increases were lower than those reported in the preceeding paper after 48 hr of TRH treatment, when intracellular prolactin equalled 450% of control and positive cells equalled 129% of control. These inconsistencies reflect differences in the control level of prolactin production rather than in the absolute effects of TRH, which were virtually identical in the successive experiments. We conclude that: (1) TRH acts to alter hormone production in cells already making prolactin; (2) TRH increases somewhat the number of prolactin‐containing cells; (3) the relative contribution of such “new” cells to increased hormone output depends on the basal level of prolactin production, which differs among individual GH3 cell colonies and varies over time in culture. This diversity does not diminish the usefulness of GH3 cells as biochemical models of hormone biosynthesis. It does hinder their valid morphological evaluation, which apparently must be controlled as carefully as biochemical experiments and should include immunocytochemical localizations, at least for the hormone at issue.
A random arrangement of albumin‐containing hepatocytes seen with histo‐immunologic methods. I. Verification of the artifact
Authors: Lebouton A. V. , Peters Masse J. 
Published: February 2005

AbstractThe cellular and subcellular localization of albumin in hepatocytes of adult male rats was established with immunofluorescence and immunoperoxidase techniques. Livers were fixed while either filled or devoid of blood. In some rats, prior treatment with cycloheximide was used to deplete the albumin content of hepatocytes. Immunofluorescence of blood‐free livers from untreated rats showed that all hepatocytes contained albumin. However, using the peroxidase method, the amount of immunoprecipitate in cisternae of the rough endoplasmic reticulum was so slight that specific localization of albumin was impossible. Yet in all cases, a positive reaction for the presence of albumin was seen on ribosomes attached to the endoplasmic reticulum. In contrast, immunofluorescence of blood‐filled livers from untreated rats and those previously injected with cycloheximide showed that only a few scattered hepatocytes were positive for albumin. In these cases, subcellular localization of albumin was obvious because the immunoprecipitate was found in heavy concentration, but only in the cytosol compartment.
Effects of serum components on the morphology of sertoli cells in culture
Authors: Hutson James C. , Garner Charles W. , Stocco Douglas M. 
Published: February 2005

AbstractStudies of Sertoli cell structure, maturation, and function have been aided by the use of in vitro systems. Although numerous papers have appeared that utilize the Sertoli cell culture model, few papers have dealt with the characterization of these cells under various culture environments. Recently, it has been reported that the addition of serum to the culture medium prevents induction of long cytoplasmic appendages in cultured Sertoli cells that have been treated with FSH, TSH, or c‐AMP. The purpose of this investigation was to determine which serum components, obtained by gel filtration, are capable of inhibiting the morphological response induced by FSH, TSH, or c‐AMP. Sertoli cell‐enriched cultures were prepared using collagenase and trypsin digestion, each followed by gravity sedimentation. Untreated cells grown on plastic or glass substrates assumed an epithelioid appearance after several days. Cells treated with FSH, TSH, or c‐AMP formed long cytoplasmic appendages after 1‐2 days. This response was prevented or reversed by the addition of fetal calf serum (10%), crystallized bovine serum albumin (0.25%‐2%), or purified albumin obtained by gel filtration of whole serum (0.25%). It was also found that fractions that elute between the void volume and the initial albumin fractions (molecular weights of approximately 50,000 and greater) mimic the hormone‐induced response after only 10‐12 hours. The results of this investigation indicate that albumin is the primary serum component responsible for inhibiting morphological alterations induced by FSH, TSH, and c‐AMP. Furthermore, it is apparent that the production of long filamentous cytoplasmic appendages in Sertoli cells can be induced by a wide variety of substances.
Serous cysts of the aging guinea pig ovary. III. Permeability of the cyst epithelium to lanthanum and horseradish peroxidase
Authors: Quattropani Steven L. 
Published: February 2005

AbstractThe permeability of the epithelium lining serous cysts of the guinea pig ovary was examined using lanthanum and horseradish peroxidase (HRP). Both lanthanum and HRP introduced at the luminal surface of the cyst penetrated to the basal region filling caveolae in both lateral and basal cell surfaces. Within three minutes of vascular infusion of HRP, the tracer was detected between epithelial cells and in caveolae on their lateral and basal surfaces but not associated with intracellular organelles. There was no change in the intracellular distribution of HRP after ten minutes. It was concluded that the epithelium was permeable to the tracers within this time period but that pinocytosis and transport of these tracers through the epithelial cell were not demonstrated.
Placental permeability during early gestation in the hamster. Electron microscopic observations using horseradish peroxidase as a macromolecular tracer
Authors: Carpenter Stanley J. 
Published: February 2005

AbstractThe permeabilities of the parietal yolk sac placenta and the preplacental region of the hamster conceptus during early postimplantation (day 8) were compared by means of electron microscopy and a macromolecular protein tracer, horseradish peroxidase (HRP). HRP was administered by injection into the maternal venous system; samples of the two placental tissues were obtained for examination at intervals between 4 minutes and 1 hour later. The three layers of the parietal yolk sac wall (from outer to inner: capsular trophoblast, Reichert's membrane, parietal endoderm) appeared to provide little impediment to the passage of HRP from perivitelline maternal blood spaces to the yolk sac cavity. HRP passed through the outer trophoblast layer, both by way of intracellular fenestrae (60‐200 nm diameter) and narrower intercellular channels, and completely permeated the meshwork of Reichert's membrane within minutes after injection. The inner parietal endoderm cell layer was widely discontinuous and clearly presented no barrier to HRP movement. HRP reaching the yolk sac cavity was avidly endocytosed by the visceral yolk sac epithelium. In contrast to the parietal yolk sac, the preplacental region of the conceptus was impermeable to HRP. Zonular occluding junctions located between contiguous cells of the chorionic ectoderm layer of the preplacenta were the obvious barrier to the HRP molecules. These results suggest that in this rodent species, during the early postimplantation period of gestation, the parietal yolk sac placenta potentially plays a more important role in the maternal‐embryonic transfer of macromolecular substances than does the preplacenta.
Isolation, culture and characterization of epithelial cells derived from rat ventral prostate
Authors: Douglas William H. J. , Terracio Louis , Glass Howard 
Published: February 2005

AbstractEpithelial‐cell enriched primary cultures have been established from rat ventral prostate (RVP). Minced ventral prostates were dissociated with 0.5% collagenase in F12K tissue culture medium containing 1% fetal bovine serum. This treatment resulted in the gradual removal of stromal elements from the base of the epithelial cells. After 60 minutes of digestion the aggregates of epithelial cells were washed and plated at high density in F12K plus 10% horse serum. After 48 hours in vitro the unattached cells were removed from the culture dishes, washed, and reinoculated into new culture vessels containing fresh medium. After 96 hours in vitro, the aggregates had attached to the culture vessels and spread out to yield discrete patches of epithelial cells. By 144 hours in vitro the patches of cells had grown and coalesced to form a semi‐confluent monolayer of epithelial cells. Ultrastructural examination of these cultures indicated that adjacent cells were joined by desmosomes and tight junctions and had formed “lumen‐like structures” into which projected microvilli. In addition, the cells contained secretory granules and tonofilaments, giving them a morphological appearance similar to prostate epithelial cells in the intact organ. The primary cultures also retained histochemical activities for acid phosphatase, β‐glucuronidase, and succinic dehydrogenase that were similar to the intact organ.
Surface ultrastructure of the isolated avian notochord in vitro: The effect of the perinotochordal sheath
Authors: Carlson Edward C. , Cristina Kenney M. 
Published: February 2005

AbstractThe perinotochordal sheath (PNS) is a “tube” of extracellular matrix (ECM) that surrounds the avian notochord beginning in the second day of development. Somites, like the notochord, derive from chordamesoblast but are encased by a less substantial perisomitic matrix (PSM). Initially both tissue types exhibit epithelioid characteristics. Somitic cells subsequently disperse, however, while notochordal histoarchitecture is maintained until much later. To test the possible shape‐preserving role of the PNS, notochords were isolated from chick embryos by homogenization (which retains the sheath) or by trypsinization (which removes the sheath). Somites were similarly isolated. Tissues were cultured 12‐72 hours and studied by LM, SEM and TEM. Mechanically isolated notochords are initially rigid with smooth surfaces. During the culture period a few cells grow outward from cut ends of the notochord, but its overall rod shape and intact PNS are maintained. In contrast, uncultured trypsinized notochords are flaccid, denuded cylinders with numerous cytoplasmic blebs. They adhere to the substratum within 12 hours of culture when a few cells break away from the central tissue rod, migrate laterally, and appear mesenchymal. This cellular dispersion is directional (perpendicular to the long notochordal axis) and continuous (up to 72 hours). At this time a flattened ovoid growth area is formed. Cultured somites form flat circular growth areas within 12 hours of culture irrespective of the isolation method. These data suggest that the maintenance of an epithelial configuration by notochords in vivo may be due in part to physical restraints of the PNS. It seems possible that notochordal secretions (manifested by the formation of a PNS) could result in its compartmentation and axial confinement while its unrestrained somitic relatives are free to disperse.
Lung development and the pulmonary surfactant system: Hormonal influences
Authors: Hitchcock Karen R. 
Published: February 2005

AbstractThe effect of hormones on developmental events is not a new area of scientific investigation. However, in the last decade, the developing lung has been the focus of an increasing amount of basic and applied research. Inadequate development of the newborn's respiratory system precludes extrauterine existence; indeed, such respiratory inadequacy has been a leading cause of death in premature infants. Tremendous strides have been made in understanding the basic cell biology of the developing lung. Much has been learned about the source, composition, and function of pulmonary surfactant, a surface‐active material produced by the lung and essential to alveolar stability. Deficient stores of this material is a major etiologic factor in the respiratory distress syndrome of the newborn (RDS). This fact, coupled with observations that certain hormones can accelerate lung development and the consequent availability of adequate stores of pulmonary surfactant, has led to a large body of literature dealing with the effects of hormones (and other agents) on lung development. It is the purpose of this literature review (1) to discuss the various kinds of investigations which have linked surfactant synthesis to the type II pulmonary epithelial cell; and (2) to review the current status of research dealing with the effects of glucocorticoids and thyroid hormons on lung maturation.
Presence and location of adrenergic nerve endings in the dental pulps of mouse molars
Authors: Avery James K. , Cox Charles F. , Chiego Jr. Daniel J. 
Published: February 2005

AbstractIn all, 30 adult (45‐day‐old) Swiss Webster mice were used for light and electron microscopic examination of the presence, number, and location of adrenergic endings in the first molar teeth. Prior to sacrifice, 10 animals received i.p. injections at 8, 6, 4, and 2 hours of 0.5 cc of 20 mg/kg solution of 5‐hydroxydopamine (5‐OH‐DA) as a label for adrenergic endings. The animals were then anesthetized, perfused with Karnovsky's fixative, and the teeth were postfixed in Osmic acid, decalcified, embedded in methacrylate, and serial‐sectioned. The sections were surveyed by light microscopy, and the number and location of nerve endings containing the reduced 5‐OH‐DA were recorded. Ten control mice were injected with the vehicle solution and prepared in the same manner. A third series of mice were given a single injection of 5‐OH‐DA, sacrificed, and prepared for ultrastructural study. The molar pulps were divided into four areas to facilitate examination: pulp horns, coronal pulp, bifurcation area, and root pulp. These four areas were further divided into three zones: odontogenic, vascular‐related, and nonvascular‐associated. The location and number of endings were evaluated, and an average of approximately 70 endings containing the 5‐OH‐DA were found in each tooth using light microscopy. These represented 35.5 ± 5.2 in the pulp horns; 26.1 ± 2.4 in the central coronal; 5.4 ± 0.7 in the bifurcation, and 5.6 ± 0.9 in the root pulp per tooth. Vascular related endings were found in greatest number, the odontogenic zone next, and free endings least. Verification of location of 5‐OH‐DA by ultrastructural analysis revealed the false transmitter in vesiculated endings in the four areas and zones of the pulp.
Aspartame administration to the infant monkey: Hypothalamic morphology and plasma amino acid levels
Authors: Reynolds W. Ann , Stegink Lewis D. , Filer L. J. , Renn Eleanor 
Published: February 2005

AbstractInfant monkeys received 2 gm/kg body weight of aspartame (APM) or 2 gm/kg body weight APM plus 1 gm/kg body weight monosodium glutamate (MSG) by gastric tube. Blood samples were obtained at intervals over the ensuing 4 hours and analyzed for amino acid levels. At this time, each infant was perfused with glutaraldehyde. The hypothalamus was embedded in plastic and then serially sectioned at 1 μ.Hypothalamic morphology was normal in all eight infants given 2 gm/kg body weight APM and in the six infants given 2 gm/kg body weight APM plus 1 gm/kg body weight MSG. By light microscopy, no pycnotic nuclei, neuronal degeneration, or dendritic swelling was noted. In both experimental and control brains, localized areas of poor perfusion exhibited abnormal morphology. Elevated plasma levels of aspartate, glutamate, and phenylalanine indicated that the test compounds were administered and absorbed. Variable rates of absorption were evident, probably due to the necessity of administering APM as a slurry, due to its low solubility. On the basis of blood absorption curves, it appears that infant monkeys metabolize aspartate and glutamate and phenylalanine somewhat more rapidly than man.It is concluded that APM given alone or with MSG, in large acute doses, does not result in hypothalamic damage in the newborn monkey.
Craniofacial, occlusal, and masticatory anatomy in bats
Authors: Czarnecki Roger T. , Kallen Frank C. 
Published: February 2005

AbstractSkull measurements from ten anatomically and behaviorally diverse genera of bats show marked variation in positioning of the face upon the cranium but a relative stability of the site of the mandibular fossa. Factors associated with maintaining occlusion in bats which exhibit dorsally‐inclined maxillary toothrows include dorsally angulated mandibular bodies and elevated condyles. Detailed comparisons are made between the generalized morphology of Myotis lucifugus and anatomical extremes represented by Rhinolophus lepidus, Mormoops megalophylla, and Pteropus giganteus. In these four bats, masticatory movements of the teeth and temporomandibular joints, despite marked interspecific variation, appear to relate to a common pattern. The beginning of jaw opening is important for maximal occlusal shear, particularly in Pteropus. Observed differences in the histology of the temporomandibular joints reflect postulated differences of pressure patterns within them. Differences in skeletal and dental morphology, together with variations in size and orientation of masticatory muscles, could account for known and postulated differences in the four respective chewing patterns, with no major variation from the known muscle firing sequences of Myotis lucifugus. Basic patterns of interaction between central nervous system and masticatory musculature would therefore appear to have undergone minimal modification. This accords with the concept that neural control of mastication is a relatively conservative mechanism; as such, it would appear to have imposed significant limitation upon adaptive change in bats.
Fine structural and biochemical effects of aminoglutethimide and o,p′‐DDD on rat adrenocortical carcinoma 494 and adrenals
Authors: Moore Robert N. , Penney David P. , Averill Kathy T. 
Published: February 2005

AbstractRats bearing adrenocortical carcinoma 494 were injected daily for 7, 14, or 21 days with aminoglutethimide (AG) or o,p′‐DDD. Reversibility of these steroidogenic inhibitors was determined by injecting other animals for either 14 or 21 days and sacrificing them 14 days later. While the drugs had little effect on body or tumor growth, plasma corticosterone levels were reduced a maximum of 88% in normal and 95% in tumor‐bearing rats during AG chemotherapy. These levels were unaltered in normal rats by o,p′‐DDD and reduced a maximum of 64% in tumor‐bearing animals. Relative adrenal weights generally increased during chemotherapy and then returned to control levels. These changes were mainly due to alterations in the lipid and mitochondrial volume fractions. Lipid increased with both drugs while mitochondria increased with o,p′‐DDD and decreased with AG. Cholesterol ester levels paralleled the lipid stereology more closely with AG than o,p′‐DDD. With both drugs the most notable changes in tumor fine structure was a decrease in mitochondrial internal membranous vesicles and matrical density. Adrenal mitochondria had the irregular, elongated forms characteristic of tumor‐bearing animals and were vacuolated (AG) or had internal rings (o,p′‐DDD). The large lipid droplets observed during chemotherapy with both drugs were replaced by numerous small droplets in recovery periods.
Fine structural study of postcastrational adrenocortical carcinomas in female CE‐mice
Authors: Sharawy Mohamed M. , Liebelt Annabel G. , Dirksen Thomas R. , Penney David P. 
Published: February 2005

AbstractPostcastrational adrenocortical carcinomas in the CE/Ki inbred strain of mice and the adrenals of noncastrated CE/Ki mice were studied using light and electron microscopic techniques. Most of the tumors appeared as large nodules of cells separated by septae comprised of collagen and blood sinusoids. The majority of tumor cells (Type 1) showed few or no lipid droplets (sudanophobic), polymorphic hyperchromatic nuclei, lack of SER, abundant RER and free ribosomes, prominent Golgi complexes, and few mitochondria with scant internal membranes. Clusters of Type 1 cells were surrounded by a basal lamina. In contrast, Type 2 cells revealed abundant and dilated tubules of SER, large number of lipid droplets and mitochondria with tubulovesicular cristae. These results suggest that Type 2 cells were probably active in steroid hormone synthesis and secretion while Type 1 cells were highly anaplastic and apparently non‐steroid‐secreting cells.
A freeze‐fracture study of the anterior and posterior latissimus dorsi muscles of the chicken
Authors: Ryan Dennis M. , Shafiq Saiyid A. 
Published: February 2005

AbstractThe sarcolemma, sarcoplasmic reticulum (SR), and T system of the anterior (tonic) and posterior (fast twitch) latissimus dorsi muscles of the chicken have been examined by the freeze‐fracture technique, and quantitative data on the P and E fracture faces have been obtained.The fractured plasma membranes reveal (a) profiles of surface caveolae, (b) randomly distributed intramembranous particles ranging in size from 40–100 Å in diameter, and (c) orthogonal assemblies composed of groups of 60 Å particles in close association, and differences with respect to all three structures are present between the tonic (ALD) and fast twitch (PLD) muscles. In the ALD muscle, the surface caveolae are more uniformly distributed and have smaller openings than in the PLD muscle; the former muscle also has a two‐fold higher caveolae density than the latter muscle. The intramembranous particles are more numerous in the ALD than in the PLD muscle in both fracture faces, but the orthogonal assemblies are fewer. The functional significance of these differences in the two fiber types are discussed.The fractured membranes of the SR have intramembranous particles (IMP's) approximately 80 Å in diameter, with a two‐fold higher packing density in the PLD than in the ALD muscle. This difference is present in both the longitudinal and cisternal components of the SR. In addition, there are collar‐like expansions (CLE's) in the SR of the ALD muscle which are particularly poor in intramembranous particles. These particles are considered to represent Ca2+ transport ATP‐ase, and the reduced density of IMP's could be a significant factor in the low calcium uptake and slow relaxation characteristics of the ALD muscle.