bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuroepithelial bodies and growth of the airway epithelium in developing hamster lung
Authors: Hoyt Richard F. , Sorokin Sergei P. , McDowell Elizabeth M. , McNelly Nancy A.
Published: February 2005

Clusters of small‐granule endocrine cells, neuroepithelial bodies (NEBs), appear in the airway lining of pseudoglandular lungs, but their prenatal function has remained obscure. Transplacental labeling of S‐phase cells in Syrian golden hamsters has allowed us to relate NEBs to patterns of replication in the surrounding endoderm. Two methods were used: (1) continuous exposure to 3H‐thymidine for the last 25% (4 days) of gestation, and 2) 2‐hr exposure to 5‐bromo‐2′‐deoxyuridine (BrdU) on fetal day 15. 3H‐thymidine incorporation was assessed in autoradiographs of neonatal lung by grain counting from 923 nonendocrine and 251 endocrine cells in 28 airway epithelial terrains, each centered on a NEB: 12 in the perihilar, 8 in the middle, and 8 in the distal third of the left axial bronchus. Grain densities for 10–25 nonendocrine cells on either side of the NEB were plotted vs. position relative to the endocrine cell cluster and analyzed by rank‐order correlation and linear regression. Label was highest in cells closest to NEBs in all 12 terrains (P < 0.05–0.001) in the perihilar airway, in 3 of 8 terrains (P < 0.025–0.001) in the middle third of the bronchus, and in respective, pooled populations (P < 0.001). The effect was not demonstrable in the distal third of the airway. In the 15‐day fetus 243 mm of airway perimeter were measured and 3,218 BrdU‐labeled epithelial cells counted from sections through the entire length of the left axial airway and the lobar bronchus, intermediate, and terminal bronchioles of the infracardiac (IC) lobe. Overall, 43% of BrdU‐labeled cells and only 24% of epithelium lay within 20 μm of NEBs. Preferential concentration of S‐phase cells around NEBs was significant (P < 0.001) by X2 test at all airway levels. Net density of NEB‐associated BrdU + cells was 10/mm of basal lamina in the trachea, rose distally along the left axial airway to 22/mm at the end of the undivided bronchus, and fell to 15/mm in the terminal channels. It was 9 cells/mm in terminal bronchioles of the infracardiac lobe. Regional differences in 3H‐thymidine and BrdU labeling patterns can be correlated with differences in the age of NEBs. We conclude that NEBs regulate local cell proliferation in developing hamster airway, probably activated in a proximal‐to‐distal wave reflecting maturational changes in the NEBs along the same gradient. © 1993 Wiley‐Liss, Inc.
Anti‐bombesin monoclonal antibodies modulate fetal mouse lung growth and maturation in utero and in organ cultures
Authors: Sunday Mary E. , Hua Ji , Reyes Bernadette , Masui Hideo , Torday John S.
Published: February 2005

Fetal pulmonary neuroendocrine cells (PNECs) contain abundant gastrin‐releasing peptide (GRP, mammalian bombesin‐like peptide [BLP]). Previously, addition of bombesin resulted in increased fetal lung growth and maturation in utero and in organ cultures. A monoclonal antibody (mAb) to bombesin (2A11) blocked baseline automaturation of lung organ cultures in serum‐free medium. In the present study, we analyze lung development following daily in utero administration of 2A11 from gestational days 15–18. Fetal lung treated with 2A11 and then harvested on day 18 demonstrated a dose‐dependent decrease in surfactant phospholipid synthesis compared to controls treated with MOPC, an unreactive mAb. However, 2A11‐treated fetal lung harvested on day 17 showed paradoxical increases in 3H‐choline incorporation into saturated phosphatidylcholine, 3H‐thymidine incorporation into DNA, and relative numbers of differentiated type II pneumocytes. In serum‐containing day 17 lung organ cultures, 2A11 stimulated choline and thymidine incorporation. Since epidermal growth factor (EGF) is the only agent besides bombesin known to stimulate both fetal lung growth and maturation, we added EGF to serum‐free cultures and reconstituted the stimulatory effects. A murine EGF receptor mAb (ERA) blocked 2A11‐induced lung growth and maturation in serum‐containing cultures, and this effect was overcome by adding EGF. In vivo, ERA also blocked stimulatory effects of 2A11 in fetal lung on day 17. These observations suggest that EGF receptor up‐regulation may maintain lung growth and maturation if BLP levels are diminished on day 17. Nonetheless, BLPs appear to be involved in lung maturation on day 18, supporting a role for PNECs in normal lung development. © 1993 Wiley‐Liss, Inc.
Paracrine effects of bombesin/gastrin‐releasing peptide and other growth factors on pulmonary neuroendocrine cells in vitro
Authors: Speirs Valerie , Bienkowski Elizabeth , Wong Veronica , Cutz Ernest
Published: February 2005

Pulmonary neuroendocrine cells (PNEC) are numerous in the fetus where they have been implicated to have a role in fetal lung development. We assessed the effects of putative growth factors, gastrin releasing peptide (GRP), cholecystokinin (CCK), gastrin (GN), serotonin (5‐HT), and epidermal growth factor (EGF), some of which are produced by PNEC, either alone or in combination, on cultured fetal rabbit PNEC from 20, 24, and 28 day fetuses. GRP increased the total protein of the cultures over a 7 day period in an age‐dependent manner, with greatest effect in cultures from the 24 day fetus, no effect with the 28 day fetus, and an inhibitory effect on 20 day cultures. This was accompanied by an increase in PNEC, which could be blocked by treatment of the cultures with a monoclonal antibody to GRP (2A11). There was no increase in 3H‐thymidine labeling of PNEC in GRP treated cultures but an increase in numbers of cells partially stained for 5‐HT, suggesting the induction of a precursor cell. Other growth factors had neither an inhibitory nor a stimulatory effect either alone or in combination with GRP. Preliminary studies with 125I‐GRP receptor localization suggests that the GRP receptor is mostly expressed on pulmonary fibroblasts, and less on epithelial cells, so that the role for GRP in fetal lung development, at least in the rabbit, is probably indirect, acting via a paracrine mechanism. © 1993 Wiley‐Liss, Inc.
Immunocytochemical expression of protein gene product (PGP) 9.5 in the cat bronchopulmonary neuroendocrine cells and nerves
Authors: Lauweryns Joseph M. , Seldeslagh Kristine A.
Published: February 2005

Variously fixed, wax‐embedded lung and gastrointestinal serial tissue sections from newborn to adult cats were stained with hematoxylin‐eosin (H&E), Grimelius' silver, and immunohistochemical techniques using antisera to protein gene product (PGP) 9.5, a neuron‐specific protein under strong evolutionary constraints. PGP 9.5 is revealed as a pan‐neuroendocrine marker useful for tracing the pulmonary diffuse neuroendocrine system (PDNES) and studying the relationships between neuronal and neuroendocrine elements at various stages of life. Its occurrence is also compared in the pulmonary and the gastrointestinal tract. In spite of a close resemblance to already described neuroepithelial bodies (NEB) of other mammals, cat NEB feature typical constitutional and distributional difference, illustrating interspecies differences.

The number of PGP 9.5 immunopositive pulmonary neuroendocrine cells declines gradually after 3 weeks and throughout adult life. Immunoreactivity in neuronal elements is lost after 1 week of age. In gastrointestinal tissues, only neuronal lelements immunostain, suggesting functional variations or a separate embryological origin for enteroendocrine cells. © 1993 Wiley‐Liss, Inc.
Localization of cholecystokinin‐like peptide in neuroendocrine cells of mammalian lungs: A light and electron microscopic immunohistochemical study
Authors: Wang Yi‐Yao , Cutz Ernest
Published: February 2005

We report immunohistochemical localization of cholescystokinin (CCK)‐like immunoreactivity at the light and electron microscopy (EM) level in pulmonary neuroendocrine (NE) cells of human and other mammals (monkey, rabbit, rat, hamster, pig, dog and lamb). In addition, immunolocalization of CCK‐like peptide was compared with that of bombesin (predominant peptide in human lung) and serotonin (an amine found in NE cells of most species). While CCK‐like and serotonin‐like immunoreactivity were identified in both solitary NE cells and NE cell clusters (neuroepithelial bodies, NEB) of all species studied, bombesin‐like immunoreactive NE cells were found in human and monkey lungs only. The distribution and intensity of immunostaining for CCK‐like peptide varied between species with some showing relatively high levels of expression (e.g., monkey, piglet, dog and lamb), others intermediate (human, rabbit) or weak immunostaining (rat, hamster). At the EM level, CCK‐like immunoreactivity was localized in dense‐core vesicles (DCV), the expected site of peptide storage. Using a double immunolabeling techniques, CCK and serotonin were colocalized in some, but not all DCV.

The potential role of CCK in the lung (or for other pulmonary peptides) may include a variety of functions such as modulation of bronchial or vascular tone, growth factor‐like and/or hormonal effects. © 1993 Wiley‐Liss, Inc.
Heterogeneity studies of hamster calcitonin following acute exposure to cigarette smoke: Evidence for monomeric secretion
Authors: Tabassian Ali R. , Snider Richard H. , Nylen Eric S. , Cassidy Marie , Becker Kenneth L.
Published: February 2005

Various acute stimuli, including cigarette smoke, induce hypercalcitonemia in man and hamsters. We have shown that this occurs also in thyroidectomized subjects. In the present study we have further explored this phenomenon of secretion from the lungs by studying, simultaneously, the HPLC characteristics of pulmonary tissue and serum in control hamsters and in animals immediately following short‐term exposure to cigarette smoke. In addition, we have studied the immunoheterogeneity of lung calcitonin 24 hours following the acute exposure. Control lungs contained monomeric immunoreactive calcitonin (M‐iCT), high molecular mass iCT (H‐iCT), and CT fragments. Immediately following smoke exposure, there was an acute decrease of lung iCT by radioimmunoassay (RIA) which consisted primarily of a decrease in M‐iCT by HPLC. Simultaneously, the iCT increase in the serum by RIA was shown by HPLC to involve M‐iCT. Twenty‐four hours after smoke inhalation, the lung iCT by RIA and M‐iCT by HPLC had returned towards control levels. These findings document the molecular characteristics of lung iCT following acute cigarette smoke stimulation, and suggest that under certain circumstances M‐iCT may be actively secreted by the lung. It remains to be determined whether this type of secretion reflects hemocrine or paracrine release and what the physiological role for such a secretion may be. © 1993 Wiley‐Liss, Inc.
Ultrastructure and morphometry of the urethral glands in normal, castrated, and testosterone‐treated castrated male mice
Authors: Parr Margaret B. , Ren Hong Ping , Kepple Larry , Parr Earl L. , Russell Lonnie D.
Published: February 2005

Recent studies of the urethral glands in the male mouse and rat have suggested that they are testosterone‐dependent glands that may be potential sites for secretory immunity in the male genital tract. In the present study we describe the ultrastructural features of these glands in normal mice and provide quantitative data on the sizes of the acinar cells and their organelles in sham‐, oil‐, and testosterone‐treated castrated mice. Acinar cells in urethral glands from normal mice contain numerous secretory granules, prominent Golgi complexes, elongated mitochondria, and an abundance of rough endoplasmic reticulum (RER) with large and dilated cisternae, all of which are features characteristic of secretory cells. In some acinar cells the cisternae of the RER were filled with closely packed, unbranched, straight, tubular structures that were oriented parallel to one another, that radiated from aggregates of dense material, or that were randomly attanged. In other acinar cells the cisternae of the RER showed a network of branching and anastomosing vesicular‐like structures whose limiting membranes were occasionally seen in continuity with the membranes of the RER. Secretory acini showed large, unbranched tubules in the acinar lumen. When cut at right angles the large tubules exhibited a distinct fuzzy outer coat with fine projections radiating outwards. The ultrastructure of the acinar cells and the presence of tubules in the lumen suggests that they are engaged in secretion of a tubular protein.

Morphometric analysis of acinar cells in the urethral glands showed that the mean volumes of nuclei, cytoplasm, secretory granules, vacuoles, and mitochondria were significantly reduced in castrated mice in comparison to either normal or testosterone‐treated castrated mice. This confirms earlier observations that the urethral glands are targets of testosterone. © 1993 Wiley‐Liss, Inc.
Why do spermatozoa of American marsupials form pairs? A clue from the analysis of sperm‐pairing in the epididymis of the grey short‐tailed opossum, Monodelphis domestica
Authors: Taggart D. A. , Johnson J. L. , O'Brien H. P. , Moore H. D. M.
Published: February 2005

In order to understand the evolutionary significance of sperm‐pairing in American marsupials, an ultrastructural investigation was made of this process in the South American grey short‐tailed opossum, Monodelphis domestica. One epididymis from each animal (5) was fixed for light and electron microscopy and divided into 18 segments. The contralateral tract was divided into similar segments and assessments made of the total number of spermatozoa and the proportion of sperm‐pairs. The mean total sperm number was 4.20 ± 0.62 × 106/epididymis. Sperm‐pairing commenced around segment 9 in the proximal corpus epididymidis and reached a maximum of 80% in the caudal sperm storage region of the duct. The sperm‐pairing process was characterised by four stages. Spermatozoa exhibited parallel alignment as indicated by the positioning of identical cross‐sections of sperm heads. This was followed by close apposition with acrosomal faces parallel rather than opposite. Rotation of the sperm heads around each other then apparently occurred as indicated by the morphological alignment of sections of paired sperm heads. Sperm‐pairing was complete when the acrosomal faces were precisely aligned and joined. Misalignment and failure to pair was observed in about 20% of spermatozoa in the cauda epididymis. Such a complex sperm‐pairing process may ensure that conjugated spermatozoa are precisely aligned so that flagella movement can be accurately coordinated for maximal progressive motility. © 1993 Wiley‐Liss, Inc.
Apical excrescences in the gallbladder epithelium of the female Syrian hamster in response to medroxyprogesterone
Authors: Gilloteaux J. , Karkare S. , Kelly T. R.
Published: February 2005

All the intact female Syrian hamsters treated with medroxyprogesterone (MP) for a one‐month period, without dietary manipulation, display gallbladder surface epithelial changes, and intraluminal deposits. These changes include excrescences in various stages, bulging, and extrusion of material from the epithelial cells. The most striking scanning electron microscopic observations are the dramatic events, comparable to apocrine‐like secretory events observed in another related study using oophorectomized hamsters. Since the hamster gallbladder does not possess mucous goblet cells, it appears that this phenomenon could be a response to the MP treatment, thus providing a larger amount of mucous product than usual with cellular material, in addition to the possible alteration in the quality of the bile following this treatment. As a result of MP treatment, intraluminal deposits were also confirmed by using light and transmission electron microscopy. In control hamsters these events were not observed, however, small blebs outlining surface epithelial cells are seen. The results in this report complement the previous studies using the male and oophorectomized Syrian hamster model subjected to similar experimental conditions. © 1993 Wiley‐Liss, Inc.
Histogenetic potential of rat hind‐limb interdigital tissues prior to and during the onset of programmed cell death
Authors: Lee K. K. H. , Chan W. Y. , Sze L. Y.
Published: February 2005

The histogenetic potential of interdigital tissues isolated from the autopod of rat embryonic hind‐limbs between 14.5 and 16.5 days was investigated. A wedge of tissue containing ectoderm and mesoderm was excised from between the developing digits and grafted beneath the kidney capsule of adult rats for two weeks. We have previously demonstrated that the renal capsule is an excellent site for permitting limb tissues to proliferate and differentiate (Chan et al.: J. Exp. Zool., 260:74–83, 1991). At 14.5 days, when cell death (revealed with neutral red stains) within the interdigital zone was limited to the apical ectodermal ridge (AER), the interdigital mesoderm was capable of developing into bone, cartilage, and loose connective tissue in the kidney. It was estimated that the skeletal elements occupied approximately 38% of the overall area of the grafts. In addition, the ectoderm was able to produce keratinized epithelium, hair follicles, and sebaceous glands. In 15.5 day autopod, necrosis was present both in the AER and the mesoderm between the AER and marginal sinus. Interdigital mesoderm obtained from this stage of development formed cartilage but not as extensively as that derived from 14.5 day autopod (4% as compared with 38%). Necrotic cells were present in all of the interdigital zones at 16.5 days. Ten explants were introduced into the kidney at this stage, but only 4 grafts were recovered after 2 weeks. In all cases, the explants did not produce cartilage. Only a small amount of keratinized epithelium and loose connective tissue was found. In summary the interdigital mesoderm has the potential to develop bone, cartilage, and loose connective tissue, but this ability is progressively lost during morphogenesis. © 1993 Wiley‐Liss, Inc.
Lymphatic endothelium isolation, characterization and long term culture
Authors: Leak Lee V. , Jones Michael
Published: February 2005

Using a collagenase trypsin‐EDTA treatment, we have been able to successfully isolate and grow primary cultures of the lymphatic endothelium (LEC) that were subcultured, frozen for storage, subsequently thawed with good recovery and growth, and serially subcultured. The morphological features of cultured LEC were consistent with that observed for the endothelium of intact lymphatic vessels. A prominent feature of growing cultures was the appearance of large vacuoles in the perinuclear region of the cytoplasm, which became filled with fluid and cell debris engulfed from the culture medium. The basal cell surface lacked a well defined basal lamina and anchoring filaments were observed extending from the basal plasmalemmal surface into the underlying substratum. LEC in cultures were also positive for Factor VIII‐related antigen. However, specific granules, characteristic of Weibel‐Palade bodies were not observed in ultrathin sections of confluent cultures. F‐actin was identified in LEC cultures using fluorescein phalloidin, and in confluent cultures actin filaments were located at the periphery of the cell as a continuous circumferential thin band and short filamentous bundles in the central part of the cell. By using heparin and endothelial cell growth supplement in the culture medium we have been able to grow stable cultures of lymphatic endothelial cells that could be maintained when serially subcultured for over two years. These LEC cultures provide an in vitro model for investigating the function and biochemical properties of the lymphatic endothelium. © 1993 Wiley‐Liss, Inc.
Transport pathways for macromolecules in the aortic endothelium: I. Transendothelial channels revealed by three‐dimensional reconstruction using serial sections
Authors: Ogawa Kazushige , Watabe Tomoyoshi , Taniguchi Kazuyuki
Published: February 2005

Three‐dimensional organization of structures labeled by horseradish peroxidase as a tracer molecule in rat aortic endothelium was examined to elucidate the transport pathways for macromolecules. Aortic endothelium was divisible morphologically into four distinct parts, i.e., the parajunctional region (JR), peripheral region (PR), organelle region (OR), and nuclear region (NR). Almost all vesicles, intercellular clefts, and phagosomes were labeled by horseradish peroxidase. Peroxidase‐positive vesicles tended to gather in the PR, occasional JR, and the upper part of the NR. Ultrathin serial micrographs revealed the transcellular channels composed of vesicles in the PR and JR, and the paracellular channels composed of the intercellular cleft without constrictions of tight and gap junctions. Transcellular channels were subdivided into three morphologically different types, where not only vesicles but invagination of abluminal membrane and intercellular cleft occasionally participated in their formation. Three‐dimensional reconstructions from three series of consecutive electron micrographs revealed that almost all peroxidase‐positive vesicles were connected directly or indirectly with the cell surface. These results indicate that the transcellular and paracellular channels are the transport pathways for macromolecules in the aortic endothelium and may suggest that the “shuttle” hypothesis is unsuitable to explain transport system for macromolecules because it postulates the existence of many free vesicles in the cytoplasm. © 1993 Wiley‐Liss, Inc.
Structure of the Golgi apparatus in stimulated and nonstimulated acinar cells of mammary glands of the rat
Authors: Clermont Y. , Xia L. , Rambourg A. , Turner J. D. , Hermo L.
Published: February 2005

The structural features of the Golgi apparatus of acinar cells of mammary glands were examined with the electron microscope in 3 groups of rats: (1) in lactating female animals at 8 days postpartum, which served as controls; (2) in female rats sacrificed at various intervals from 2 to 30 hours following separation from their 8‐day old pups; and (3) in females separated from their 8‐day‐old pups for a period of 12 hours and returned to their litters for durations of 1, 2, 4, and 8 horus. In animals of group 2, the Golgi stacks remained identical to that of controls between 2 and 8 hours. At 12 hours and later, the Golgi stacks decreased progressively in size, but the number of elements composing the stacks remained similar to that of lactating females and all contained casein submicelles. At 24 and 30 hours, typical secretory granules containing casein micelles disappeared from the trans aspect of the stacks. The earliest and most striking changes observed in the Golgi apparatus of the rats of group 2 took place at 12 hours. At this time, the prosecretory and secretory granules decreased considerably in volume and lost most of their electron‐lucent content. This indicated that the delivery of small molecules, i.e., lactose and H2O, to these structures was soon altered following arrest of the sucking stimulus. In animals of group 3, the size of prosecretory and secretory granules and the amount of their electron‐lucent content reverted to normal at 4 hours. Thus the influx of lactose and H2O into these structures appears to be rapidly restored after returning the pups to their mothers. The decrease in size of the Golgi stacks noted at 12, 18, and 24 hours following arrest of lactation (group 2), was accompanied by an increase in number of small vesicles that formed clusters next to the Golgi stacks and in “wells.” Thus in these regressing Golgi stacks, many of the associated small vesicles appear to arise by vesiculation of the saccules. © 1993 Wiley‐Liss, Inc.
Glucocorticoid regulation of surfactant‐associated proteins in rabbit fetal lung in vivo
Authors: Durham Paul L. , Wohlford‐Lenane Christine L. , Snyder Jeanne M.
Published: February 2005

The effects of a maternally administered synthetic glucocorticoid, betamethasone, on the levels of mRNA for the surfactant proteins SP‐A, SP‐B, and SP‐C and on the levels of SP‐A protein were investigated in day 27 gestational age rabbit fetal lung tissue. Betamethasone administration to the pregnant rabbit caused approximately a twofold increase in the fetal lung level of SP‐A protein and a threefold increase in fetal lung SP‐A mRNA levels when compared to levels in fetuses obtained from saline‐treated or uninjected animals. SP‐B mRNA was increased fourfold in fetal lung tissue obtained from glucocorticoid‐treated pregnant does when compared to levels in fetuses of uninjected pregnant does. However, SP‐B mRNA levels in fetal lung tissue from saline‐injected controls were also significantly elevated, ∼twofold, when compared to fetal lung SP‐B mRNA levels in the uninjected control condition. SP‐C mRNA levels in lung tissue of fetuses from both saline‐injected and betamethasone‐injected pregnant does were increased similarly, ∼twofold, over SP‐C mRNA levels in fetal lung tissue obtained from uninjected control does. These data are suggestive that betamethasone treatment increases fetal lung SP‐A and SP‐B mRNA levels and that maternal stress alone can increase the expression of SP‐B and SP‐C mRNA in rabbit fetal lung tissue. Using in situ hybridization, SP‐A mRNA was shown to be present primarily in alveolar type II cells in fetuses of control and saline‐injected does. However, SP‐A mRNA was easily detected in both alveolar type II cells and bronchiolar epithelial cells of rabbit fetal lung tissue following maternal betamethasone treatment. In contrast, SP‐B and SP‐C mRNA were present only in alveolar type II cells of lung tissue obtained from fetuses of control, saline, or betamethasone‐treated does. Thus maternal administration of glucocorticoids increased SP‐A protein as well as SP‐A and SP‐B mRNA levels in rabbit fetal lung tissue. SP‐A mRNA was localized to both alveolar type II cells and in smaller amounts in bronchiolar epithelial cells of rabbit fetal lung tissue. However, SP‐B and SP‐C mRNA were detected only in alveolar type II cells. © 1993 Wiley‐Liss, Inc.
Cardiac neural crest contribution to the pulmonary artery and sixth aortic arch artery complex in chick embryos aged 6 to 18 days
Authors: Waldo Karen L. , Kirby Margaret L.
Published: February 2005

Previous studies of cardiac neural crest (CNC) migration in early chick embryos demonstrated CNC cells in the media of pharyngeal arch arteries three, four, and six, and in the most proximal part of the developing pulmonary arteries. The objectives of this study were to learn (1) to what extent the CNC is involved in the later development of the pulmonary arteries, (2) how the CNC cells are distributed in the sixth aortic arch artery including the wall of the ductus arteriosus in the older embryo, and (3) what happens to the CNC as the pulmonary artery/sixth arch complex grows into its adult configuration. Quail‐to‐chick chimeras were used to study CNC distribution in embryos aged 6 to 18 days. Controls (undisturbed chick embryos) were collected with chimeras. Each was fixed, processed, sectioned, stained with Feulgen‐Rossenbeck stain, and analyzed. The results demonstrated that CNC disappeared from the proximal pulmonary arteries by embryonic day 9 and played no further role in pulmonary artery development. With the exception of the endothelium, CNC completely filled the wall of the sixth aortic arch artery as far distally as its junction with the dorsal aorta in younger embryos and with the aorta in older embryos, thus suggesting the possibility of proximodistal migration of CNC along the sixth aortic arch. The ductus wall, filled with CNC, was intimately associated with the recurrent laryngeal nerve, also filled with CNC, thereby strongly suggesting a role for CNC in ductal closure. © 1993 Wiley‐Liss, Inc.
Cytologic structures unique to deiters cells of the cochlea
Authors: Spicer Samuel S. , Schulte Bradley A.
Published: February 2005

Deiters cells in the gerbil cochlea disclosed unusual ultrastructural features. A sharp transition zone separated the cell body underlying outer hair cells into an upper compartment with numerous organelles and a lower part devoid of structures other than the microtubule stalk. Deiters cells exhibited a unique structure, the rosette complex, which consisted of a core of densely fibrillar trabeculae, enclosed in a filamentous meshwork and surrounded by tubulocisternal endoplasmic reticulum. The dense trabeculae radiated in columns downward from an apical translucent area toward a lucent zone around the nucleus. They also spread to the medial plasmalemma enveloping nerves and upward into the base of the phalanx. Frequent, small Golgi complexes bordered the tubular reticulum. The distinctive mitochondria of Deiters cells frequently paralleled the plasmalemma, revealed an elongated, often arched profile, and contained sparse, longitudinally aligned cristae. The stalk, composed of characteristic microtubule bundles resembling those in pillar cells, ascended from basal to apical plasmalemma of the cell body and into the phalanx and reticular lamina as previously described. The stalk appeared also to ramify into smaller microtubule bundles in apical cytosol penetrating the rosette complex. Nuclei in Deiters cells differed from those in hair cells in their location high in the cell and in showing chromatin dispersion indicative of more active protein synthesis. © 1993 Wiley‐Liss, Inc.
The name cranial ovarian suspensory ligaments in mammalian anatomy should be used only to indicate the structures derived from the foetal cranial mesonephric and gonadal ligaments
Authors: van der Schoot P.
Published: February 2005

The term ovarian suspensory ligament appears ambiguous when human adult anatomy textbooks are compared with human embryology or with general mammalian anatomy textbooks. The term ovarian suspensory ligament in laboratory rodents and domestic animals indicates homologous structures during foetal (the cranial mesonephric and gonadal ligaments) and later life (the cranial mesonephric ligament derivatives). In human foetal anatomy textbooks ovarian suspensory ligament is generally applied to this same ligament. However, in human adult anatomy textbooks ovarian suspensory ligament is widely applied to the part of the (uterine) broad ligament which contains the uterine and ovarian blood and lymphatic vessels and nerves. This inconsistency in human anatomy books raises confusion on the nature of the foetal and adult ovarian suspensory ligaments and inconsistencies in the description of the normal anatomical relationships of the ovaries between humans and other mammals. For the proper understanding of normal gonadal growth and development within the abdomen, it is important to maintain a consistent nomenclature of the cranial ovarian structures. The current practice in veterinary and other mammalian textbooks offers a solid point of departure. © 1993 Wiley‐Liss, Inc.
Vagal nerve maturation in the fetal lamb: An ultrastructural and morphometric study
Authors: Hasan Shabih U. , Sarnat Harvey B. , Auer Roland N.
Published: February 2005

The maturation of the left vagal nerve was studied in the fetal lamb by transmission electron microscopy and by computer‐assisted morphometry of sections of the entire nerve at seven gestational ages between 79 and 145 days (term is 147 days) and in the adult ewe. The number of unmyelinated axons per Schwann cell progressively decreased from 25 to 55 at 79 days to 1 to 5 at near‐term. Unmyelinated axons of various sizes were enclosed within a single Schwann cell at all ages, but the mean axonal diameter increased in inverse relation to the number of unmyelinated axons. A few Schwann cells enclosed two myelinated axons, but in most instances myelination did not begin until a 1:1 ratio was achieved; some single axons with a Schwann cell remained unmyelinated in the adult. Myelinated fibers were rare at 79 days but myelination progressed rapidly thereafter until the adult ratio of myelinated: unmyelinated fibers was reached at about 100 days; myelinated axons were not uniformly distributed. The myelin sheaths and axons of small fibers progressively increased in diameter in late gestation, but new large fibers were not added. Early myelinating fibers and immature unmyelinated axons contained more microtubules than neurofilaments; neurofilaments predominated in mature axons with or without myelin. Cross‐linkages between neurofilaments were already evident by 79 days. Maturation of the vagal nerve thus occurs first by an increase in number of myelinated fibers and then by an increase in the size of each fiber in this fixed population. The bimodal distribution in the size histogram of myelinated fibers is not achieved until 134 days gestation and correlates well with physiological maturation of respiratory patterns. © 1993 Wiley‐Liss, Inc.
Functional morphology of the vascular plexuses associated with the cetacean uterus
Authors: Rommel Sentiel A. , Ann Pabst D. , McLellan William A.
Published: February 2005

The cetacean reproductive system is surrounded by thermogenic locomotory muscle and insulating blubber. This arrangement suggests elevated temperatures at the uterus that could induce detrimental effects on fetal development. We present anatomical evidence for a complex countercurrent heat exchange system that could function to regulate the thermal environment of the uterus and a developing fetus. Cooled venous blood from the surfaces of the dorsal fin and flukes enters the abdominal cavity via the lumbo‐caudal venous plexus. This plexus is juxtaposed to the arterial and venous plexuses associated with the uterus. The morphology of the lumbo‐caudal venous plexus suggests that it acts as a “heat sink” for the adjacent tissues. Heat may be transferred to the cool, lumbo‐caudal venous plexus from the warm blood in the arterial and venous plexuses supplying the uterus. Heat may also be transferred from adjacent locomotory muscles to the cool lumbo‐caudal venous plexus. The countercurrent heat exchanger created by the juxtaposition of the lumbo‐caudal venous plexus with the uterovarian arterial plexus is similar in design to that of the countercurrent heat exchanger described for male cetaceans. The functional implications of introducing cool superficial blood into the abdominal cavity of a diving, and locomoting female cetacean are discussed. © 1993 Wiley‐Liss, Inc.
Differentiation of clara cells and pneumocytes of the rat by means of enzyme‐ and immunohistochemistry
Authors: Kudo Shigeharu
Published: February 2005

Localization of non‐specific esterases, Cu‐Zn superoxide dismutase and dehydropeptidase‐I, in rat lung was investigated enzymecytochemically or immunohistochemically. Esterase was demonstrated in Clara cells, type II pneumocytes, and septal cells (or vitamin A‐storing lung cells), to a somewhat lesser extent in type I pneumocytes and ciliated epithelial cells of the bronchioles, and to a minor extent in interstitial fibroblasts of the alveolar septum. Large amounts of esterase reaction product were deposited in the rough endoplasmic reticulum and the nuclear envelope in Clara cells, type II pneumocytes, and septal cells, in addition to smaller amounts in other organelles. No reaction product was found in macrophages (histiocytes) in alveolar septi and alveolar macrophages, except for the primary lysosomes or phagolysosomes and trace amounts in the Golgi vesicles, and none in endothelial cells of alveolar blood capillaries, except for primary lysosomes. Immunolocalization of Cu‐Zn superoxide dismutase was generally limited to a particular area of Clara cells. A constriction occurred in the apical cytoplasm of Clara cells between an immunoreactive dome‐like protrusion and the non‐immunoreactive cytoplasm of the supranuclear area, and the dome‐like protrusion appereared to be pinched off in a ball‐like or oval from. Immunolocalization of dehydropeptidase‐I was demonstrated in a dome‐like protrusion or supranuclear area of Clara cells or throughout the cytoplasm and in the surface plasma membrane of mesothelial cells. The presence of these enzymes in Clara cells suggests a contribution to the detoxification system of the lung, together with cytochrome p‐450‐dependent monooxygenase systems. © 1994 Wiley‐Liss, Inc.
Neoformation of blood vessels in association with rat lung fibrosis induced by bleomycin
Authors: Peão Mário N. D. , Águas Artur P. , de Sá Carlos M. , Grande Nuno R.
Published: February 2005

We have used intratracheal instillation of bleomycin in rats to study the microanatomical changes of blood vessels associated with lung fibrosis. Bleomycin is a toxic cytostatic drug employed in classical models of lung fibrosis. Wistar rats were submitted to intratracheal injection of 1.5 units of bleomycin and sacrificed 2.5 months later, a timing when marked fibrosis of the lung is observed. We casted the vascular tree of the rat lungs by perfusion with a methacrylate resin. These caste were studied by scanning electron microscopy. Lung tissue was also studied by light microscopy and thin section electron microscopy. The major vascular modifications observed in the bleomycin‐treated rats were: (1) neoformation of an elaborate network of vessels located in the peribronchial domains of the lung, and (2) distortion of the architecture of alveolar capillaries. By light microscopy, it was clear that the newly formed vascular network was located in regions of fibrosis (which in the resin casts were digested away). These neoformed vessels appeared to originate from bronchial arteries. Thin section electron microscopy revealed that endothelial cells of the neoformed vessels were plump, presented large nuclei, and showed numerous pinocytotic vesicles that were also observed in subendothelial pericytes. The alveoli of the bleomycin‐treated rats were heterogeneous in size and shape in contrast with the homogeneity of alveoli of control animals. The alveolar capillaries of fibrotic lungs appeared to occupy a larger volume of the alveolar wall than alveolar capillaries of control rats. Our findings indicate that lung fibrosis encompasses marked changes of the vascular system, namely, the neoformation of vessels and the rearrangement of alveolar capillaries. These structural changes suggest that fibrotic transformation of the lung is associated with the local generation of angiogenic stimuli. © 1994 Wiley‐Liss, Inc.
Septation of the respiratory and digestive tracts in human embryos: Crucial role of the tracheoesophageal sulcus
Authors: Sutliff Katharine S. , Hutchins Grover M.
Published: February 2005

Esophageal atresia and tracheoesophageal fistula, common malformations of the respiratory and digestive tracts, are of unsettled pathogenesis. Part of the difficulty in understanding these abnormalities arises from the uncertainties about the normal developmental processes in the region. This study examined the development and fate of the tracheoesophageal septum. Normal human embryos from the Carnegie Embryological Collection and fetuses from the Hopkins Pathology Collection were examined, and reconstructions of selected specimens were made from photomicrographs of serial histologic sections. The results show that the lung bud appears in Carnegie stage 12, rapidly enlarges, and bend caudally, thereby producing a sulcus between the foregut and the respiratory system on its caudal aspect. The cranial aspect of this tracheoesophageal sulcus remains fixed at the levels of the first cervical vertebra throughout subsequent embryonic and fetal development. At the same time the trachea and esophagus elongate to bring those parts of the respiratory and digestive systems into their definitive anatomic positions. Examination of the tracheoesophageal sulcus shows that its growth‐limiting properties may be explained by its catenoidal configuration. Catenoidal, or saddle‐shape, sulci have been shown to have similar regional growth‐limiting properties in the embryonic heart. These regions contrast with outwardly convex regions in both the developing heart and lung where growth of the tissues occurs. The observations made here suggest that the origin of the tracheoesophageal malformations must be sought in a configurational abnormality in the area of the developing lung bud in Carnegie stage 12. © 1994 Wiley‐Liss, Inc.
High field magnetic resonance imaging of normal and pathologic human medulla oblongata
Authors: Vandersteen M. , Beuls E. , Gelan J. , Adriaensens P. , Vanormelingen L. , Palmers Y. , Freling G.
Published: February 2005

High field proton magnetic resonance (MR) imaging has been applied to depict the MR appearaance of the normal excised human cervicomedullary junction, based on which neuropathologic specimens can be described. More specifically, two normal cases and one case of Chiari deformity were imaged in the transverse, sagittal, and coronal dimensions using a 9.4 Tesla vertical bore magnet. The MR images of the normal specimens reveal most of the neuroanatomical microstructures described in literature. An accurate description of the Chiari deformity could be made by comparing the MR reference images with those of the pathologic specimen. All MR detected abnormalities were confirmed by histopathology, by which no additional lesions could be found. © 1994 Wiley‐Liss, Inc.
Characterization of a testis specific protein localized to endoplasmic reticulum of spermatogenic cells
Authors: Ohsako Seiichiroh , Bunick David , Hess Rex A , Nishida Takao , Kurohmaru Masamichi , Hayashi Yoshihiro
Published: February 2005

Background: In order to understand the mechanism of spermiogenesis, it is important to characterize germ cell specific genes and proteins expressed during spermatogenesis. We previously reported that a mouse monoclonal antibody, 1C9, raised against golden hamster testis homogenate, recognized a 103 kDa protein in hamster spermatogenic cells (Ohsako et al.; J. Vet. Med. Sci., 53:969–974, 1991). In the present study, we have determined the precise stage and intracellular localization of this protein.

Materials and Methods: Hamster, mouse, and rat tissues were used for immunocytochemistry, SDS‐PAGE, and immunoblotting. Immunoelectron microscopy was performed using Lowicryl K4M embedded hamster testis and colloidal gold conjugated second antibody. Furthermore, immuno‐affinity purification was carried out using a 1C9‐Sepharose column.

Results: In immunoblot analysis, 1C9 also recognized a 103 kDa protein and a 101 kDa protein in the rat and the mouse testes, respectively. Ten different hamster tissues other than testis did not show reactivity against 1C9. In immunostained paraffin sections of hamster testis, the initial staining appeared in middle pachytene spermatocytes and persisted until maturation phase spermatids (step 15). However, it was no longer detectable in the subsequent steps of spermatids. In addition, strong staining was observed in the post‐nuclear region of elongated spermatids. Immunoelectron microscopic analysis showed that the protein was localized to the endoplasmic reticulum (ER) and nuclear envelope of spermatogenic cells, but not in the other organelles, such as Golgi apparatus and acrosome of the spermatids. This protein appears to be associated with ER membrane. Furthermore, this protein is found exclusively in the testicular microsomal fraction, not in the cytosol. By affinity purification, approximately 320 μg of the 103 kDa protein was obtained from 10 hamster testes. The purified 103 kDa protein was unaffected by N‐glycanase, indicating it does not have asparagine‐linked glycoconjugates.

Conclusions: These results indicate that the protein recognized by 1C9 appears to be a unique protein that is localized in the ER and nuclear envelope of spermatogenic cells. © 1994 Wiley‐Liss, Inc.
Development of the high endothelial venule in rat lymph node autografts
Authors: Sasaki Katsunori , Pabst Reinhard , Rothkötter Hermann‐Josef
Published: February 2005

Vascular reconstruction during rat lymph node regeneration was investigated in autotransplanted mesenteric lymph node fragments, which had been implanted in the renal parenchyma. In addition to light microscopy, vascular casting and transmission electron microscopy were used. From day 3 onwards capillaries grew into the autografts together with lymphatic vessels. The capillaries showed obvious signs of proliferation by day 5. The surviving interstitial cell at the outer border of the transplant produced extracellular substance. High endothelial venules (HEV) differentiated from capillaries from about day 7. A first sign of their development was a vessel with a narrow, branching luminal space and with endothelial cells containing rich cytoplasm and small Golgi complexes. As the Golgi complexes grew and the cisternae and vesicles increased, the lumen dilated, the cell coat on the luminal surface became prominent, and, finally, lymphocytes emigrated through these venules from around day 10. The typical lymph node structure was complete by day 28. These results suggest that the interaction among the remaining interstitial cells, invading capilaries, and lymphatic penetration results in differentiation and maturation of HEV in lymph node regeneration. The development of Golgi complexes is strongly associated with lymphocyte emigration from the blood. © 1994 Wiley‐Liss, Inc.
Fine structure of taste buds located on the lamb epiglottis
Authors: Sweazey Robert D. , Edwards Chris A. , Kapp Beth M.
Published: February 2005

Background: Taste buds located on the aryepiglottal folds and laryngeal surface of the epiglottis are the principal receptors responsible for the initiation of the laryngeal chemoreflex. In contrast to the wealth of information available concerning the ultrastructure of oral taste buds, little comparable data exists for taste buds located at the entrance to the larynx. Therefore, the present study was designed to investigate the fine structure of taste buds located on the lamb epiglottis.

Materials: Stained thick and semi‐serial thin sections from taste buds located on the lamb epiglottis were examined with light and electron microscopy.

Results: Based on morphological criteria, three types of cells could be identified in the taste bud: Type I, Type II, and basal cells. Both Type I and Type II cells extended into the apical taste pore, but there were differences between these two cell types with regard to nuclear profiles, electron density, and the relative density of ribosomes, apical mitochondria, and rough and smooth endoplasmic reticulum. Basal cells did not extend a process into the taste pore. Nerve processes were observed throughout the taste bud. Synapses were observed between both Type I and Type II cells and nerve fibers. These synapses exhibited membrane thickenings and accumulations of clear and dense‐cored vesicles of varying proportions in the taste cell cytoplasm adjacent to membrane specializations.

Conclusions: The taste buds located on the lamb epiglottis share several structural similarities to taste buds located in the oral cavity and other regions of the pharynx and larynx of many mammalian species. The presence of synapses on both Type I and Type II cells of the lamb epiglottal taste bud suggests that both cell types are involved in laryngeal chemorecption. © 1994 Wiley‐Liss, Inc.