bluuebunny/crossref_metadata_2025 huggingface dataset:
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

Intramedullary 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

Epithelial 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

The 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

An 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

Thyrotropin‐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.
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

The 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

The 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

Studies 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

The 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

The 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

Epithelial‐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

The 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

The 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

In 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

Infant 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

Skull 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

Rats 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

Postcastrational 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

The 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.
Characterization of endosteal bone‐lining cells from fatty marrow bone sites in adult beagles
Authors: Miller Scott C. , Bowman Beth M. , Smith James M. , Jee Webster S. S.
Published: February 2005

Bone‐lining cells cover the majority of trabecular bone surfaces in adult long‐lived mammals. The morphology, ultrastructure, and population density of bone‐lining cells was investigated in several fatty marrow trabecular bone sites in adult beagles of different ages. Although there is a low population density of bone‐lining cells on bone surfaces, their total numbers greatly exceed the numbers of osteoblasts and osteoclasts found on these bone surfaces. In one of the bone sites studied, there are significantly fewer bone‐lining cells in very old beagles (12–16 years old) when compared to young adult beagles (1.5–3 years old), otherwise there are no differences in the cell population that could be attributed to aging. Bone‐lining cells are flattened against bone surfaces and have flat or sometimes ovoid‐shaped nuclei which are often located adjacent to areas in the fatty marrow where capillaries are found. When viewed in the electron microscope, bone‐lining cells contain few organelles, and the attenuated cytoplasm of these cells is well extended over bone surfaces. The bone‐lining cell cytoplasm does not appear to form a continuous layer over the bone surface, as numerous gaps and spaces are seen. Bone‐lining cell processes are frequently joined by junctions morphologically similar to gap junctions. Between the lamina limitans of the bone matrix and the bone‐lining cell, as well as between the bone‐lining cell and the adjacent fat cells, there are layers of connective tissue containing collagenous fibers and other amorphous material. These findings are discussed in relation to the possible role of bone‐lining cells in the regulation of mineral homeostasis.
Ultrastructural classification of paracrystalline inclusions in untreated and estrogen treated human Leydig cells
Authors: Payer Andrew F.
Published: February 2005

Ultrastructural examination of untreated and estrogen‐treated human testes revealed for the first time five types of paracrystalline inclusions in the cytoplasm of Leydig cells. The distinctions between each type of inclusion were based on longitudinal and cross‐sectional ultrastructure. The inclusions were not found in Leydig cells containing Reinke crystals, nor were different types of inclusions found in the cytoplasm of the same cell. One form of inclusion or Reinke crystals were occasionally found in the nucleus. Some Leydig cells with intranuclear inclusions contained the same or a different type of inclusion in the cytoplasm. The present study revealed five types of paracrystalline inclusion in contrast to the one or two types described in previous reports. A possible explanation for this difference is that earlier investigators based their observations on small pieces of tissue obtained from biopsy, while the present data were obtained by studying many regions of each testis. All five types of paracrystalline inclusions were found in relatively normal as well as azoospermic (estrogen‐treated) testes.
Heterogeneity of tight junction morphology in extrapulmonary and intrapulmonary airways of the rat
Authors: Schneeberger Eveline E.
Published: February 2005

In the present study morphology of tight junctions was related to the various cell types lining extrapulmonary and intrapulmonary airways of the rat. Freeze fracture replicas were prepared from extrapulmonary airway epithelium derived from the cartilagenous and membranous sides of upper, middle, and lower thirds of the trachea. Intrapulmonary airway epithelium was obtained from airways < 1 mm in diameter. Tight junction fibrils on the P fracture face were organized into three types of patterns. Type 1: parallel, sparsely interconnected lumenal fibrils with large ablumenal fibril loops. Type 2: richly interconnected lumenal fibrils with large ablumenal fibril loops. Type 3: narrow network of interconnected fibrils. On the E fracture face complementary grooves were organized in a similar pattern. Ciliated cells on both sides and all levels of the trachea were associated with type 1 junctions. In intrapulmonary airways, however, the junctional pattern of ciliated cells changed to type 2. Brush cells at all levels of the airways were bounded by type 2 and occasionally by type 1 junctions. Secretory cell junctions displayed the following patterns: Mucous cells were bounded solely by type 3, serous cells by either types 2 or 3, and Clara cells predominantly by type 2. Cells tentatively identified as intermediate cells displayed all three junctional patterns. The number of parallel fibrils comprising tight junctions was higher in extrapulmonary as compared to intrapulmonary airways. No difference was seen in the various locations sampled in the trachea. Gap junctions were observed between secretory cells of extrapulmonary but not intrapulmonary airways. These observations are discussed in relation to current physiologic data.
Connective tissue arrangement in respiratory airways
Authors: Young Christine D. , Moore G. William , Hutchins Grover M.
Published: February 2005

Connective tissue provides dynamic stability to the architecture and mechanical function of the lungs. This study examines the parenchymal connective tissue components of the alveolar ducts, their associated respiratory bronchioles and respective alveoli. Thick sections 100μ and 200μ, and serial sections at 8μ of lungs of different ages were examined histologically after fixation in distention. The varying proportions and spatial architecture of the collagen and elastic fibers and the packing and spatial interrelationships of alveoli were studied using graphic serial reconstruction. Alveolar mouths typically have a polygonal configuration as they arise from the airways. Denser connective tissue passes through the polygonal array and forms a helix encircling the airway. Polygonal packing of alveolar mouths provides a mechanically stable ductular structure with conservation of materials. A helical modification of the polygonal arrangement permits reversible changes in linear and circumferential airway dimensions.
A simultaneous comparison of the cells of blood, renal hilar and thoracic duct lymph in the dog
Authors: Garber S. L. , O'Morchoe P. J. , O'Morchoe C. C. C.
Published: February 2005

A simultaneous morphological and quantitative profile was obtained of the cells of blood, thoracic duct, and renal hilar lymph in the dog. Monolayer cytocentrifuged preparations were used to determine the number, type, and size of cells in the three compartments. The cell count of renal lymph was not related to that of blood or thoracic duct lymph. There was a greater percentage of lymphoid cells in the afferent lymph than could be accounted for by the random movement of cells from the blood to the lymph. Thus, there appeared to be a selective transit of cells from blood to lymph. Monocytes and neutrophils were largely absent from the thoracic duct lymph; however, eosinophils were present. Cells were observed in hilar lymph that were characteristic of cells subjected to antigenic stimulation. It was concluded that lymphocytes have a preferential pathway from blood to lymphatic and in the course of this pathway they undergo a change which is consistent with an active immunological role.
Further studies on catecholamine‐containing specific endothelial granules in carp cerebral veins. A fluorescence histochemical and electron microscopy study
Authors: Iijima Tadahiko , Wasano Takeo
Published: February 2005

The effects of noradrenaline (NA), L‐3, 4‐dihydroxyphenylalanine (L‐DOPA), 5‐hydroxydopamine (5‐OHDA), 6‐hydroxydopamine (6‐OHDA), and reserpine (RES) on the uptake, accumulation, and release of amines in cate‐cholamine‐containing specific endothelial granules (SEG) of carp cerebral veins and their mode of formation were examined by fluorescence histochemistry and electron microscopy. The intramuscular injection of NA (4 mg/kg) or L‐DOPA (200 mg/kg) resulted in an increase in both the fluorescence and electron density of SEG. After the administration of false neurotransmitters, 5‐OHDA (190 mg/kg) or 6‐OHDA (200 mg/kg), the venous endothelia fluorescence almost completely disappeared but the SEG electron density increased. Following the injection of RES (15 mg/kg), the fluorescence intensity and SEG electron density showed no sign of decrease, as was expected, but in fact increased. It is suggested that the SEG are able to take up and accumulate exogeneous amines and that these mechanisms are RES‐resistant. The electron density of SEG increased in proportion to the amount of amines in the SEG. The swelling and fragmentation of rough endoplasmic reticulum cisternae and the accumulation of dense material within the cisternae suggests the possible participation of these organelles in SEG formation.
The autonomic innervation of the human urinary bladder, bladder neck and urethra: A histochemical study
Authors: Klück P.
Published: February 2005

The autonomic innervation of smooth muscle in fresh biopsy specimens of the human urinary bladder, bladder neck and urethra has been examined using specific neurohistochemical techniques. Acetylcholinesterase‐containing nerve fibers have been demonstrated amongst the smooth muscle cells in all the biopsy samples. Enzyme‐positive fibers formed a plexus, the density of which varied dependent upon the region from which the biopsy material was obtained. Catecholamine (noradrenaline)‐containing autonomic nerve fibers were observed amongst smooth muscle cells of the vesico‐urethra junction; other than for perivascular nerve plexuses. Noradrenergic fibers were absent from biopsy samples of other regions. Juxtamural, acetylcholinesterase‐positive neurones were present in some samples, and a proportion of these cell bodies were closely related to noradrenergic nerve terminal regions. These findings are discussed in relation to those of other workers who have examined the innervation of the mammalian lower urinary tract.
Fine structure of the spermatic granuloma of the rat vas deferens following vasectomy
Authors: Kennedy Samuel W. , Heidger Paul M.
Published: February 2005

Light and electron microscopic studies of the spermatic granuloma of the rat vas deferens which arises post‐vasectomy were undertaken to determine if such granulomata exhibit the morphological features typical of granulomata described in other systems. Vasectomy was performed utilizing a technique of division and fulguration, and tissues for study were fixed in situ by means of vascular perfusion at 2, 4, or 12 weeks post‐operatively. Invariably, a spermatic granuloma formed at the testicular end of the sectioned vas by 2 weeks post‐vasectomy. At the time periods studied, the granulomata exhibited a cellular wall of variable thickness and complexity surrounding a central mass of sperm. This wall consistently was divisible into (1) a loosely arranged interface region populated by neutrophils and other spermiophagic cells, and (2) a more peripheral, compactly arranged region populated primarily by macrophages and epithelioid cells. Multinucleate giant cells were especially prominent in the later stages studied. Peripheral to the wall, but without an intervening basal lamina, lay a loosely organized, highly vascular connective tissue region containing only sparse collagen and few fibrocytes. Here, too, macrophages, epithelioid cells, lymphocytes, and plasma cells were noted in abundance. A well‐developed capsule composed of fibrocytes, collagenous bundles, and smooth muscle cells surrounded the granuloma. Such features conform to those descriptions in the literature of chronic granulomatous inflammation.
Characterization of intensely fluorescent cells in the liver of the rat I. Histochemistry and 48/80‐induced degranulation
Authors: Dimlich Ruth V. W. , Reilly Frank D. , Meineke Howard A. , McCuskey Robert S.
Published: February 2005

The nature of the intensely fluorescent cells (IFC) in the livers of male Sprague‐Dawley rats was evaluated using histochemical and pharmacological techniques. The number and distribution of IFC in portal areas were quantified using some of these techniques. Cells which were metachromatic as well as fluorescent for serotonin, histamine, and heparin were observed in the connective tissue of the portal space, hilus, and capsule of the liver. Cells with the characteristics of chromaffin, enterochromaffin, or enterochromaffin‐like cells were not seen in these locations. Intravenous administration of compound 48/80, a known mast cell degranulator, caused a significant decrease in the number of fluorescent and metachromatic cells in the portal areas of the liver. However, no significant difference was found in the number of cells counted in either the 48/80 or control groups when comparing the data from several histochemical methods. These results provided evidence that: (1) IFC demonstrate both fluorescence and metachromasia and, therefore, are mast cells, (2) compound 48/80 causes a comparable decrease in the number of serotonin and histamine fluorescent as well as metachromatic cells, indicating concomitant rather than differential release of serotonin, histamine, heparin, and/or other metachromatic substances, and (3) each of the three histochemical methods appears of equivalent sensitivity when used to study the effect of various factors (i.e., 48/80) on the release of endogenous substances from IFC. The results of this study indicate that the effects of 48/80 in vivo might be mediated through the release of various vasoactive substances from these IFC (mast cells).
Development of the cornea during fetal life: Comparison of corneal and bulbar diameter
Authors: Harayama Kenji , Amemiya Tsugio , Nishimura Hideo
Published: February 2005

Two hundred twenty undamaged human fetuses without external malformations were supplied by the human embryo and fetus collection at the Department of Anatomy, Kyoto University. The diameters of the cornea and eyeball were measured by slide calipers under a stereomicroscope.

The various diameters of the eyeball showed a parallel, linear increase from the 12th to the 28th week of menstrual age. Corneal diameters appeared to increase in parallel with the eyeball as a whole until the 16th week of menstrual age; later on their rate of growth declined.

The corneal limbus could be recognized macroscopically at the 17th week of menstrual age and was distinctly seen from the 20th week of menstrual age. The corneal curve at the limbus began to be a little convex at the 21st week of menstrual age and became distinctly convex from the 23rd week. The cornea was transparent from the 12th to the 28th week of menstrual age. The sclera lost its transparency from the 21st week.

It is significant that during fetal life the sagittal diameter of the eyeball is shorter than the vertical and transverse diameters.
Freeze‐fracture study of rat ventral prostate: Secretory mechanisms in the epithelial cell
Authors: Kachar Bechara , Da Silva Pedro Pinto
Published: February 2005

Membrane events during apocrine and merocrine secretion of rat ventral prostate epithelial cells were analyzed by freeze‐fracture. Early morpho‐logical manifestation of both secretory modes involves focal clearance of microvilli characterized by their progressive inclination and attenuation over the apical membrane. Merocrine secretion includes invasion of the apical microfilament web by the secretory vesicle and clearance of membrane particles at the site of its interaction with the apical plasmalemma. During apocrine secretion, a portion of the plasma membrane cleared of microvilli projects into the lumen. Growth of this projection is accompanied by a progressive, but partial, clearing of membrane particles and results in the formation of a large bleb containing dilated endoplasmic reticulum cisternae. Completion of the process involves “degeneration” of the bleb and its release by constriction of a neck and, possibly, fusion of vesicular or tubular structures. Swelling and blebbing of microvilli are shown to be preparation artifacts.