bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histological organization of the right and left atrioventricular valves of the chicken heart and their relationship to the atrioventricular purkinje ring and the middle bundle branch
Authors: Lu Ying , James Thomas N. , Bootsma Marianne , Terasaki Fumio 
Published: February 2005

AbstractIn the avian heart the right and left atrioventricular (AV) valves not only exhibit their own special anatomical characteristics, but they also are in close proximity to the conduction system. The right AV valve is a single, spiral plane of myocardium, in remarkable contrast to the fibrous structure characteristic of the mammalian tricuspid valve. A ring of Purkinje tissue encircles the avian right AV orifice and connects to the muscular valve. The chicken has no crista supraventricularis, its right AV valve serving that function as well as opening and closing the right AV orifice. The left AV valve consists of three leaflets instead of the two typical of mammalian hearts. Its anterior and posterior leaflets are small; its large aortic (medial) leaflet merges with the bases of both the left and noncoronary cusps of the aortic valve by fibrous tissue, resembling that of the mammalian heart. However, unlike in mammals, there is a slim cylinder of continuous myocardium coursing parallel to this fibrous junction. This unusual arc of myocardium in the chicken serves to complete an entire subaortic ring of myocardium and is thus potentially capable of constricting the outflow tract of the chicken's left ventricle. The middle bundle branch connects with both the muscle arch and the AV Purkinje ring. Thus the myocardium in or near both AV valves (and the left ventricular outflow tract) in the chicken heart is so arranged that it may receive direct early activation from the conduction system. ©1993 Wiley‐Liss, Inc.
Effects of prolactin on α and β chloride cells in the gill epithelium of the saltwater adapted tilapia “Oreochromis niloticus”
Authors: Pisam M. , Auperin B. , Prunet P. , Rentier‐Delrue F. , Martial J. , Rambourg A. 
Published: February 2005

AbstractTilapia (Oreochromis niloticus), 21 g average body weight, were divided into two groups. A group was maintained in fresh water, whereas another group was adapted for 2 weeks to 20% salt water. Among the latter, fishes were injected every 2 days for a week with tilapia prolactin (ti‐PRL I). Gills were prepared for electron microscopy in order to determine the types and surface areas of chloride cells in each experimental condition. Two types of chloride cells, the α and β cells were easily distinguished on the basis of their location and ultrastructural features in the gills of freshwater fishes, while only one type of cell, the saltwater α cells presumably derived from the transformation of the freshwater α cells, were encountered in saltwater adapted animals. After PRL injection ofsaltwater adapted fishes, small chloride cells, which displayed ultrastructural features similar to those of β cells in freshwater tilapia, reappeared in interlamellar regions of the gills. In the same experimental conditions, the voluminous saltwater α cells showed a tendency to resume ultrastructural features more characteristic of the freshwater α cells from which they were derived. These observations tend to indicate that prolactin behaves as a “freshwater adapting hormone” and that β cells are specifically involved in fish adaptation to freshwater living conditions. © 1993 Wiley‐Liss, Inc.
Immunohistochemical analysis of rat liver using a monoclonal antibody (HAM8) against gap junction
Authors: Fujikura Yoshihisa , Ohta Hidehiko , Hirai Toshio , Fukumoto Tetsuo 
Published: February 2005

AbstractFour monoclonal antibodies were raised against crude gap junction fractions of rat liver to clarify the distribution of gap junctions during animal development and to analyze gap junction expression in vivo and the polarity of hepatocytes in vitro. Among the monoclonal antibodies obtained, HAM8 antibody recognized the 27‐kDa rat liver gap junction protein connexin 32. This antibody recognized gap junctions at the contiguous faces of hepatocytes, and the antigen was also observed in exocrine pancreas and salivary gland but not in kidney, heart, esophagus, or thymus. HAM8 did not react with amphibian or fish liver, heart, esophagus, stomach, or intestine as assessed via the immunofluorescence method on frozen sections. A few hepatocytes and many hemopoietic cells were seen in rat fetal liver at 15 days of gestation. HAM8 antigen was expressed on some hepatocytes but not on any hemopoietic cells. As the fetus grew, the number of hepatocytes in the liver increased gradually, together with the amount of HAM8 antigen. The distribution of HAM8 antigen at 25 days after birth was similar to that in adult liver. When the expression of HAM8 antigen was examined in primary cultured hepatocytes using the immunofluorescence method, the antigen was observed clearly between the hepatocytes. However, most of the HAM8 antigen on the free surface of hepatocytes disappeared within 4 hr. HAM8 antigen was not expressed on AH7974 rat hepatoma cells when they formed small islets in the rat peritoneal cavity or within the liver. When HAM8 IgG antibody was injected intravenously, the HAM8 signal was expressed in the liver. © 1993 Wiley‐Liss, Inc.
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

AbstractClusters 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

AbstractFetal 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

AbstractPulmonary 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

AbstractVariously 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

AbstractWe 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

AbstractVarious 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

AbstractRecent 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

AbstractIn 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

AbstractAll 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

AbstractThe 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.