bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulmonary neuroendocrine cells in pediatric lung disease: Alterations in airway structure in infants with bronchopulmonary dysplasia
Authors: Johnson Dana E. , Anderson W. Robert , Burke Barbara A. 
Published: February 2005

AbstractDespite four decades of investigation, the function of pulmonary neuroendocrine cells (NEC) remains unclear. Since NEC secretory products may influence airway growth or differentiation or alter airway smooth muscle tone, increased numbers of NEC seen in bronchopulmonary dysplasia (BPD) may be partially responsible for the genesis of the structural and pathophysiological alterations seen in this disease state. Changes in airway structure were studied in six infants dying with BPD and six conceptional age‐matched control infants dying of noncardiopulmonary disease. Changes in bombesin‐, calcitonin‐, and serotonin‐immunoreactive NEC were quantified in lung specimens from three infants who died at 2 months of age with severe BPD and three conceptional age‐matched controls. There were no differences in either bronchiolar or bronchial airway epithelial areas, but significant increases in bronchiolar (1.8‐fold) (P < 0.001) and especially bronchial smooth muscle (2.5‐fold) (P < 0.001) were documented in infants with BPD. Few bombesin‐, calcitonin‐, and serotonin‐immunoreactive cells were identified in cartilaginous airways; however, there was a clear increase in the total number of bronchiolar immunoreactive cells in infants with severe BPD (28.5 ± 11.2 cells/mm airway epithelium) compared to control infants (4.5 ± 4.9) (P < 0.05). Our results confirm that airway wall composition does change in BPD, but there is either no or an inverse correlation between NEC number and airway epithelial and smooth muscle areas and cell numbers. The role of NEC secretory products in airway smooth muscle growth and function requires further investigation. © 1993 Wiley‐Liss, Inc.
Cholinergic‐nicotinic control of growth and secretion of cultured pulmonary neuroendocrine cells
Authors: Nylen Eric S. , Becker Kenneth L. , Snider Richard H. , Tabassian Ali R. , Cassidy Marie M. , Linnoila R. Ilona 
Published: February 2005

AbstractDispersed newborn hamster lung cells were established in vitro in a defined, low‐serum growth medium. Neuroendocrine markers (immunohistochemistry for bombesin/gastrin‐releasing peptide and calcitonin) revealed a cellular predominance of pulmonary neuroendocrine (PNE) cells. While the supernatant concentration remained stable, the concentration of PNE cell immunoreactive calcitonin (iCT) gradually declined over 4 weeks. Supplementation of the medium with nicotine for 3 weeks prevented this decline in cellular iCT. Concurrently, the number of cells and [3H]thymidine incorporation were significantly increased. The stimulatory effect of chronic nicotine was reversed by the coadministration of the nicotinic antagonist hexamethonium. In another set of experiments, prior multiple transplacental nicotine pretreatments resulted in a significant increase in iCT in the lungs of newborns; when these lungs were subsequently placed in cell culture without nicotine, despite the higher concentration of iCT, there was a drop in iCT similar to that observed in the control culture. In contrast, in vivo, the lung iCT remained significantly elevated at 1 week postparturition. Cell culture supernatants were analyzed at week 4 for the evoked release of iCT; cholinergic‐nicotinic agonists promptly increased the supernatant iCT, which was blocked by nicotinic but not by muscarinic antagonists. We suggest that this in vitro system provides a useful tool to study directly the PNE cell. The acute and chronic effects of nicotine are most likely related to stimulation of cholinergic‐nicotinic receptors on iCT‐containing PNE cells. © 1993 Wiley‐Liss, Inc.
Colocalization of peptide hormones in neuroendocrine cells of human fetal and newborn lungs: An electron microscopic study
Authors: Stahlman Mildred T. , Gray Mary E. 
Published: February 2005

AbstractThis study investigated the colocalization of the peptide hormones bombesin or calcitonin with calcitonin gene related peptide (CGRP) in neuroendocrine cells (NE) in the lungs of human fetuses of varying gestational ages and in the lungs of newborn infants who died with acute or chronic lung disease in the first weeks or months after birth. Double immunolabeling of dense core granules for these peptides was also studied in this same patient population. On‐grid double gold immunolabeling was carried out on 29 subjects using anti‐bombesin and anti‐CGRP and on 22 subjects using anti‐calcitonin and anti‐CGRP as primary antibodies, the secondary antibodies being labeled with different‐size gold spheres. Colocalization of both bombesin and calcitonin with CGRP was demonstrated, not only in the same NE cell, but also on the same dense core granule. Colocalization was rarely found in normal fetuses, and most frequently found in newborn infants with acute lung disease, usually hyaline membrane disease (HMD), or with the development of chronic lung disease in the first weeks or months after birth. Double labeling of the same dense core granules might imply action of peptides in concert, or perhaps one peptide acting in a paracrine role (e.g., on bronchial or bronchiolar smooth muscle) and the second peptide acting in an autocrine fashion on the parent cell (e.g., in the regulation of granule production or release). © 1993 Wiley‐Liss, Inc.
BMPs induce direct bone formation in ectopic sites independent of the endochondral ossification in vivo
Authors: Sasano Yasuyuki , Ohtani Eriko , Narita Kenji , Kagayama Manabu , Murata Masaru , Saito Takashi , Shigenobu Keiichi , Takita Hiroko , Mizuno Morimichi , Kuboki Yoshinori 
Published: February 2005

AbstractBone formation in vivo occurs via two major processes, one of which depends on pre‐existing cartilage, and the other does not. Bone morphogenetic proteins (BMPs) have been suggested to induce cartilage formation from non‐skeletogenic mesenchymal cell population, which results in osteogenesis through the endochondral sequence. In the present study we examined if BMPs could cause direct bone formation independent of pre‐existing cartilage using bovine fibrous collagen membrane (FCM) as a carrier for BMPs. Bovine metatarsal bone was extracted in 4 M guanidine HCl and BMPs were partially purified through the hydroxyapatite chromatography and the Heparin‐Sepharose CL6B chromatography. The carrier was loaded with BMPs and then implanted in Wistar rats subcutaneously. The implants were fixed together with surrounding tissue every week after implantation and processed for von Kossa stain, immunohistochemistry, and electron microscopy. The phenotypes of bone and cartilage were identified histologically and immunohistochemically using antibodies against type I and type II collagen. Cartilage and bone were independently induced by 2 weeks. The bone formed directly on the collagen substrate of FCM without pre‐existing cartilage. Calcification occurred in the carrier as well as the cartilage and bone matrix. The present study suggests that the BMPs induce osteogenesis in vivo independent of the endochondral sequence. © 1993 Wiley‐Liss, Inc.
Perinatal development of gubernacular cones in rats and rabbits: Effect of exposure to anti‐androgens
Authors: Van Der Schoot P. , Elger W. 
Published: February 2005

AbstractIn male rats gubernacular cones develop during the latter half of prenatal life. Inversion of these papilla‐like organs after birth is the first step to postnatal growth of the muscular cremaster sacs. The factors regulating prenatal growth and differentiation or postnatal inversion of these gubernacular cones are unknown. The lack of a detailed and unequivocal description of the normal gubernacular cone growth is judged at least partially responsible for this ignorance. The present study therefore describes the normal development of the gubernacular cones in male and female rats from day 14 of fetal life.Androgens are hypothesized to control male gubernacular cone development but recent evidence throws doubt upon this proposal. Therefore, the second part of this study describes perinatal development of gubernacular cones in male rat foetuses exposed to the anti‐androgen flutamide from day 10 after conception. Quantitatively normal growth occurred prior to birth, indicating no role of androgen in this process. Excessive growth in length was noticed during the neonatal period together with delay of gubernacular cone inversion. These developmental alterations did not represent direct anti‐androgen–induced modifications of gubernacular cones development as the alterations were not observed in flutamide‐exposed neonatally castrated animals.Failure of androgens to affect directly perinatal gubernacular cone growth could represent a rat‐specific feature. Fetal rabbits show the development of similar structures during the second half of fetal life. The third part of this study examined the effect on the development of these structures of exposure of male and female foetuses to the anti‐androgen cyproterone acetate. The latter compound inhibited male internal and external genital development but allowed unaltered gubernacular cone growth.The observations in this report thus present the normal pattern of perinatal gubernacular cone growth in rats together with evidence that these organs show male‐specific growth independent of androgen. Further work should reveal the testicular or other factors responsible for this part of male bodily sexual differentiation processes. © 1993 Wiley‐Liss, Inc.
Seasonal changes of the blood‐testis barrier in viscacha (Lagostomus maximus maximus): A freeze‐fracture and lanthanum tracer study
Authors: Morales Alfonsina , Cavicchia Juan C. 
Published: February 2005

AbstractAdult male viscachas (Lagostomus maximus maximus) were gathered from their natural habitat during the period of complete spermatogenesis (June) and during the month of maximum testicular regression (August). The testes were processed by conventional electron microscopic technique using lanthanum nitrate (electron‐dense intercellular tracer) to define the intercellular spaces below the inter‐Sertoli tight junctions and by freeze‐fracture techniques.During complete spermatogenesis the tracer surrounds spermatogonia, preleptotene, and leptotene spermatocytes and stops at the level of the inter‐Sertoli tight junctions below all germ cells displaying synaptonemal complexes (zygotene‐pachytene spermatocytes) and germ cells in more advanced stages of differentiation. Conversely, during testicular regression the tracer percolates all intercellular spaces between Sertoli cells and the remaining germ cells (spermatogonia and few preleptotene and leptotene spermatocytes.) During complete spermatogenesis, freeze‐fracture replicas exhibit numerous inter‐Sertoli tight junction strands parallel to each other and to the basal lamina. During spermatogenesis decay, the inter‐Sertoli tight junctions are found to be short, tortuous, frequently interrupted, and often associated with extented membranous areas of gap junctions. © 1993 Wiley‐Liss, Inc.
Expression and accumulation of interstitial collagen in the neonatal rat heart
Authors: Carver Wayne , Terracio Louis , Borg Thomas K. 
Published: February 2005

AbstractSignificant physiological changes occur in the heart following birth including increased arterial blood pressure and heart rate. Concurrently, biochemical and structural alterations are evident in the neonatal heart in response to these dynamic physiological properties. Prominent among these is the elaborate development of the cardiac extracellular matrix, composed primarily of interstitial collagen. The collagenous fibers, together with other matrix components, form and elastic, stress‐tolerant network which functions in the dissipation of force throughout the heart wall. The present studies have used biochemical and molecular techniques to show the temporal and spatial patterns of interstitial collagen accumulation expression during late fetal and neonatal development of the rat heart. The use of biochemical and particularly molecular methodologies allows the analysis of the expression of matrix components at a resolution previously not attained by structural studies alone. These data show relative increases in interstitial collagen immediately following birth as well as spatial differences in collagen mRNAs within the heart. The data presented provide further evidence for a role of mechanical stimulation in the regulation of collagen gene expression during this period of heart development. © 1993 Wiley‐Liss, Inc.
Quantitative ultrastructural analysis of the periaqueductal gray in the rabbit
Authors: Meller S. T. , Dennis B. J. 
Published: February 2005

AbstractThe fine structure of the periaqueductal gray (PAG) of the rabbit was examined using the transmission electron microscope. On the basis of synaptic polarity, vesicle size, and the nature of the pre‐ and postsynaptic elements, 10 essentially different synaptic types could be discerned (6 axo‐dendritic, 2 axo‐somatic, 1 axo‐axonic, and 1 dendro‐dendritic). Synaptic contact on the soma of PAG neurons were small and covered, on average, only 1.6% of the soma surface. The most striking feature of the synaptic structure of the PAG was that more than 94.1% of all synapses were axo‐dendritic. Of these, 83.5% were of the symmetrical type. Most of these contacts occurred on buttons of small to medium size, and contained either round vesicles of medium size or pleomorphic vesicles of medium size. Boutons containing only flattened vesicles were quite rare. Boutons contacting larger dendrites were generally small‐to‐medium in size, made asymmetric‐type synaptic contacts, and contained pleomorphic vesicles of medium‐to‐large size. Medium‐sized dendrites were contacted principally by small boutons exhibiting either symmetrical or asymmetrical junctions containing medium‐sized pleomorphic vesicles, and in addition a few of these boutons contained both large, and small, round vesicles. Dendritic spines were generally provided with only one synaptic contact, stretching the entire width of the spinous process. Boutons and the spines on dendrites were approximately the same size. Synapses between two vesicle‐containing structures (axo‐axonic or dendro‐dendritic synapses) were rare (1.4%). They were generally asymmetric and contained round vesicles of medium size. Complex synapses, where a glial sheet enclosed the synapse, were occasionally observed. Also seen were multiple synapses, with up to 11 contacts on a single dendritic profile. Large dense‐core vesicle were seen in approximately 40% of all synapses, whereas small dense‐core vesicles were only found in about 3%. Data is provided on how different synaptic features relate to ventral, lateral, dorsal, and medial PAG. Principally this is in relation to neuron size, glia cell content, axonal characterization, and vesicular type. © 1993 Wiley‐Liss, Inc.
Incidence and histology of human accessory parotid glands
Authors: Toh Hidetoshi , Kodama Jun , Fukuda Jinichi , Rittman Barry , Mackenzie Ian 
Published: February 2005

AbstractThe parotid glands of 228 Japanese human cadavers were examined to determine the incidence and histological features of accessory parotid glands. The incidence was found to be 56% with no differences between right and left sides or between sexes. Thirty parotid glands and their associated accessory glands were examined histologically: eight of these accessory glands were found to be mixed secretory glands (i.e., containing both serous and mucous acini). Thus, the pattern of differentiation of a significant fraction of accessory glands differs from that of the main parotid gland: it appears that mixed acini, present in the early stages of development, persist into later life, and their presence may be related to tumors developing at these sites. © 1993 Wiley‐Liss, Inc.
Immunocytochemistry of ambiguous cells in adult and embryonic dwarf (dw) mouse pituitaries
Authors: Wilson Doris B. , Wyatt Darlene P. 
Published: February 2005

AbstractIn the pars distalis of the pituitary gland in adult and embryonic dwarf (dw/dw) mutant mice, ambiguous cells exhibiting ultrastructural features common to growth hormone (GH) cells and prolactin (Prl) cells were analyzed by means of colloidal gold ultrastructural immunocytochemistry in order to define the functional nature of these peculiar cells. Adult and 18‐day embryonic pituitaries from normal (+/+; dw/+) and dwarf (dw/dw) mice were processed with antibodies to GH, Prl, TSH (thyroid‐stimulating hormone), ACTH (adrenocorticotropic hormone), LH (luteinizing hormone), FSH (follicle‐stimulating hormone), and HCG (chorionic gonadotropic hormone). In the adult and embryonic dwarf pituitaries, the ambiguous cells reacted negatively to all of the antibodies except for anti‐ACTH, which labeled them well. In addition, the ACTH‐positive cells showed a much wider variety of shapes and granule size and distribution, as compared with normal adults. In the embryos, this variability in ACTH cell morphology occurred not only in dwarf embryos, but in their normal counterparts as well. The results thus suggest that adult dwarf pituitaries may retain an embryonic or incompletely differentiated form of ACTH cells. © 1993 Wiley‐Liss, Inc.
Aging and the Meynert cells in rhesus monkey primary visual cortex
Authors: Peters Alan , Sethares Claire 
Published: February 2005

AbstractWe have assessed the effects of aging on the cell bodies of the large Meynert cells in layers V and VI of the rhesus monkey primary visual cortex by comparing the frequency, size, and cytology of these neurons in three young (5–6 years of age), one middle‐aged (12 years of age), and four old monkeys (25–35 years of age). In the young monkeys there is an average of 20.8 Meynert cells beneath 1 mm2 of cortical surface, and in the old monkeys the value is 22.3 cells. The cell bodies of these large pyramidal cells do not become smaller with age, and surprisingly they accumulate only small amounts of lipofuscin. The conclusion is that in the rhesus monkey there is no loss of Meynert cells with age and that aging has little effect on the morphology of the cell bodies of these neurons. © 1993 Wiley‐Liss, Inc.
Ultrastructural characteristics of in vivo and in vitro fertilization in the grey short‐tailed opossum, Monodelphis domestica
Authors: Taggart D. A. , O'Brien H. P. , Moore H. D. M. 
Published: February 2005

AbstractTo establish the mode of fertilization in a marsupial, a morphological investigation was made of the gametes of the South American grey short‐tailed opossum, Monodelphis domestica, at the time of fertilization in vivo and in vitro. Oestrus was induced in females by the introduction of an unfamiliar male. To obtain oocytes recently fertilized in vivo, females were killed 18–24 hours after the first mating and the region of the oviduct containing eggs excised and fixed. Unfertilized mature oocytes were recovered from ovarian follicles 15–18 hours after first mating and fertilized in vitro with cauda epididymal spermatozoa in a modified MEM medium supplemented with bovine serum albumin at 37°C in 5% CO2 in air. Following sperm‐egg binding and fertilization, oocytes were fixed and prepared for light and electron microscopy.Spermatozoa unpaired prior to fertilization in vivo and in vitro and single spermatozoa bound to the zona surface by their plasmalemma overlying the acrosome on the dorsal face of the sperm head. The acrosome reaction was only observed at the zona surface (suggesting that it may be induced by zona components) and involved a vesiculation of sperm plasma and acrosomal membranes over the main body of the acrosome but not over the narrow, marginal region which persisted after the acrosome reaction was complete. Sperm penetration of the zona pellucida caused a large breach in the zona and the dispersal of perivitelline material. The fusion of the spermatozoon with the oolemma occurred first over the marginal acrosomal region and was accompanied by a fertilization cone which protruded through the zona penetration hole. Activation of the egg was characterized by the release of material from vesicles in the peripheral cytoplasm and extrusion of the second polar body.The mode of fertilization in Monodelphis was compared with what is known in other marsupials (New World and Australian) and eutherian (placental) mammals. It was concluded that the general features of the acrosome reaction and sperm‐egg fusion may be essentially similar in both groups and that an evolutionary schism did not occur following the development of the eutherian mode of fertilization. © 1993 Wiley‐Liss, Inc.
Cell behaviors underlying notochord formation and extension in avian embryos: Quantitative and immunocytochemical studies
Authors: Sausedo Roger A. , Schoenwolf Gary C. 
Published: February 2005

AbstractFormation and extension of the notochord is one of the earliest and most obvious events of axis development in vertebrate embryos. In birds, prospective notochord cells arise from Hensen's node and come to lie beneath the midline of the neural plate, where they assist in the process of neurulation and initiate the dorsoventral patterning of the neural tube through sequential inductive interactions. In the present study, we examined notochord development in avian embryos with quantitative and immunological procedures. Extension of the notochord occurs principally through accretion, that is, the addition of cells to its caudal end, a process that involves considerable cell rearrangement at the notochord‐Hensen's node interface. In addition, cell division and cell rearrangement within the notochord proper contribute to notochord extension. Thus, extension of the notochord occurs in a manner that is significantly different from that of the adjacent, overlying, midline region of the neural plate (i.e., the median hinge‐point region or future floor plate of the neural tube), which as shown in one of the previous studies from our laboratory (Schoenwolf and Alvarez: Development 106:427–439, 1989), extends caudally as its cells undergo two rounds of mediolateral cell‐cell intercalation and two‐three rounds of cell division. © 1993 Wiley‐Liss, Inc.
Organization of the extraocular and preganglionic motoneurons supplying the orbit in the lesser galago
Authors: Sun Wensi , May Paul J. 
Published: February 2005

AbstractThe retrograde tracer wheat germ agglutinin‐conjugated horseradish peroxidase was used to establish the organization of the extraocular muscle motoneuron pools in a prosimian, Galago senegalensis, for comparison with the organization in monkeys and non‐primates. Medial rectus motoneurons were distributed in three subgroups in the ipsilateral oculomotor nucleus, a pattern similar to that of the monkey. Furthermore, the other component of the near response system, the preganglionic parasympathetic motoneurons, were confined within the Edinger‐Westphal nucleus, as in the monkey. In contrast, the distribution of the levator palpebrae and superior rectus motoneurons was similar to that of the cat. Specifically, the majority of levator palpebrae motoneurons were located contralaterally, in the caudal central subdivision of the oculomotor nucleus, and the superior rectus motoneurons had a dorsocaudal location in the contralateral oculomotor nucleus. The distributions of motoneurons supplying the superior oblique and lateral rectus muscles were similar to those of other mammals. Unlike previously studied species, the galago was found to have two accessory muscles, that lie beneath the medial and lateral rectus muscles. Motoneurons supplying the accessory rectus muscles were found ventrolateral to the main abducens nucleus, in a position similar to that occupied by the cat accessory abducens nucleus; although others may be present in the main nuclei. Taken together, these results suggest that the organization of extraocular and preganglionic motoneurons in the galago exhibits both monkey and non‐primate features. These observations are consistent with the notion that the galago is a primate species whose oculomotor organization is more similar to the general mammalian scheme. © 1993 Wiley‐Liss, Inc.