bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exogenous cytokines enhance survival of macrophages from organ cultured embryonic rat tissues
Authors: Sorokin Sergei P. , McNelly Nancy A. , Hoyt Richard F. 
Published: February 2005

AbstractBackground: Macrophage precursors are present in embryonic rats shortly after the onset of hematopoiesis. During organogenesis they soon establish residency in many parts of the body and become convertible into phagocytes, at first gaining morphological characteristics of macrophages and later a range of surface antigens used to characterize subpopulations in adults. Nonetheless, it is uncertain whether representatives of this fetal lineage continue to exist past birth. We investigated the question indirectly by seeing if such cells can be made to survive in vitro to an age equivalent to adulthood and by examining underlying conditions that favor this outcome.Methods: Fourteen‐day embryonic lungs, hearts, and limb buds were organ cultured on a firm serum‐containing medium. Fetal macrophages developed within all explants and then migrated out to form a corona of cells surrounding each explant. The lung cultures were selected for subsequent work which mainly used coronal area as the measure of macrophage population size in experimental and control groups. Baseline growth and survival of macrophages were established for cultures grown on standard medium, then effects of the following were examined: indomethacin (10−6M) as it influences initial production of macrophages from precursors and later survival of differentiated cells; and macrophage colony‐stimulating factor (M‐CSF), used alone at moderate dosage (50–100 U), and combined with granulocyte‐macrophage CSF (both 200 U), for its importance to long‐term survival of the population. Mitogenic influence of M‐CSF on differentiated macrophages was demonstrated by uptake of 5‐bromo‐2′‐deoxyuridine.Results: Indomethacin inhibited the formation of macrophages from precursors but enhanced the survival of differentiated cells. M‐CSF increased BrdU uptake of differentiated macrophages and permitted coronal growth to continue long past the ∼30 day limit of controls. Beyond this interval, M‐CSF was essential for macrophage survival, since coronas quickly shrank after the cytokine was withdrawn. Administration of the M‐CSF/GM‐CSF mixture to the 2 oldest M‐CSF‐exposed cultures between 98 and 127 days in vitro resulted in an increase in the number of coronal macrophages (P < 0.001); withdrawal between 129 and 140 days led to a decrease (P < 0.005). Ultimately a few cells were still surviving at 183 days.Conclusions: Intrinsic factors promote early formation of macrophages within the explants, but the availability of factors is lessened by the anti‐inflammatory action of indomethacin. Its later promotion of macrophage survival may be based on suppression of autogenous prostaglandin (PGE2) synthesis. M‐CSF greatly promotes macrophage survival; in context this is sufficient to show that the fetal macrophage line has a clear potential to survive well into adulthood. © 1994 Wiley‐Liss, Inc.
Morphological and kinematic study of the tongue and buccal cavity in the lizard Anguis fragilis (Reptilia: Anguidae)
Authors: Toubeau Gerard , Cotman Christophe , Bels Vincent 
Published: February 2005

AbstractBackground. The ability to detect chemical cues is highly developed in Scleroglossa, and particularly in anguid lizards. This ability was predicted because anguids possess a well‐developed vomeronasal organ (VNO) (or Jacobson's organ) and rely largely on chemical cues in various behaviours as other active foragers. In this work, we have investigated the possible functional association between tongue flicking and the VNO in the lizard Anguis fragilis.Methods. The morphology of the tongue and the buccal cavity was investigated by light and scanning electron microscopy. The kinematics of tongue and jaw movements was studied by high speed cinematography.Results. The epithelial cells of the ventral aspect of the tongue tips show microstructures (microridges, microfacets, micropores) which are not present on other areas of the mouth. Beneath the tongue, the floor of the buccal cavity shows two concave‐like elevations suggesting a structural analogy with the anterior processes described in snakes. The apex and the internal margin of these processes bear parallel oblique ridges. Taste buds occur anteriorly on the buccal floor and on the palate and are abundant on the internal side and on the edge on the anterior processes. The tongue showed three modes of tongue flicking: simple downward extension, single oscillation, and multiple oscillations. At each tongue flick, the ventral surface of the tips was observed contacting the substratum. Immediately after the tongue retraction, the buccal floor moved slightly upward. The observation of tongue flicking with the mouth open showed that the anterior processes moved upward when the tongue was retracted.Conclusions. These observations suggest the following: (1) during tongue flicking the ventral surface of the tongue tips invariably makes contact with the substratum; (2) the microstructures of the tongue tips and the ridges of the anterior processes might be helpful for collecting and receiving, respectively, chemicals during tongue flicking; (3) the anterior processes may be apposed on the roof of the mouth next to the ducts of VNOs when the buccal floor is fully elevated; (4) due to their localization, the taste buds could be equally stimulated by the molecules transferred during tongue flicking. © 1994 Wiley‐Liss, Inc.
Differentiation of periodontal ligament fibroblasts into osteoblasts during socket healing after tooth extraction in the rat
Authors: Lin Wen‐Lang , McCulloch Christopher A. G. , Cho Moon‐Il 
Published: February 2005

AbstractBackground: The entire socket after tooth extraction is filled with new bone formed by osteoblasts (Obs), but the origin of these Obs remains unknown. Thus, the proliferation and migration of paravascular and endosteal fibroblastic cells and periodontal ligament (PDL) fibroblasts (Fbs) and their differentiation into Obs during socket healing after extraction of the first maxillary molars of the rat were investigated.Methods: The proliferative activity and migration of these cells in the sockets after tooth extraction were studied using radioautography and immunohistochemistry after injection of 3H‐thymidine and 5‐bromo‐2′‐deoxy‐uridine (BrdU), respectively. Their morphological changes during differentiation was investigated by transmission electron microscopy.Results: One day after tooth extraction, PDL Fbs were the major cell type in the PDL remnant of the socket. Proliferation was low (labeling index (LI) = approximately 2%) until 16 h after tooth extraction but dramatically increased to a maximum level 1 day postextraction (LI = 23%). Between 1 and 2 days, numerous PDL Fbs in the PDL remnant actively migrated into the coagulum and continued to proliferate. On the basis of the high proliferative activity and small number of cellular organelles responsible for procollagen synthesis, these cells appear immature. At 3 days, Fbs contained more cellular organelles and deposited more collagen fibers as they replaced the coagulum with dense connective tissue and the LI declined. At 4 and 5 days, some of the Fbs began to differentiate into Obs, and the proliferation of Fbs dramatically decreased to baseline values. The migration of PDL Fbs and their differentiation into Obs were investigated by labeling with 3H‐thymidine or BrdU 1 day after tooth extraction. Heavily labeled Fbs were observed in the PDL remnant at 1 day, in the coagulum at 2 days, and in the dense connective tissue at 3 days. Labeled Obs associated with new bone were seen 4 days after injection. Endosteal and paravascular Fbs also proliferated, but at a lower level and at later time periods than the PDL Fbs. Surprisingly, endosteal and paravascular Fbs contributed only a small population of Fbs to socket healing.Conclusions: These results indicate that PDL Fbs after tooth extraction actively proliferate, migrate into the coagulum, form dense connective tissue, and differentiate into Obs which form new bone during socket healing. © 1994 Wiley‐Liss, Inc.
Apical structures of “mitochondria‐rich” α and β cells in euryhaline fish gill: Their behaviour in various living conditions
Authors: Pisam M. , Le Moal C. , Auperin B. , Prunet P. , Rambourg A. 
Published: February 2005

AbstractBackground: One of the characteristic features of the two types (α and β) of “mitochondria‐rich” (chloride) cells in the gill epithelium of freshwater fishes is the presence in their apical region of tubulovesicular structures. A further analysis of the ultrastructural features of these apical elements as well as that of their modifications under various living conditions should help to understand better the respective rǒle of both α and β cells in these conditions.Methods: Atlantic salmon (Salmo salar) maintained in fresh water as well as tilapia (Oreochromis niloticus) maintained either in fresh water or in deionized water or in 20% saltwater were examined. Measurements of surface areas of apical structures in the various living conditions were also performed.Results: In the α cells of freshwater fishes, the apical structures consisted of isolated vesicles containing a filamentous material resembling that coating the apical surface. They were closely related to the apical plasma membrane and did not penetrate the region containing the tubular system. When fishes were transferred to deionized water, the number of the apical membrane folds increased significantly, as did the number and size of apical structures which became elongated. In saltwater‐adapted fishes, the apical structures showed a tendency to collapse and took the appearance of flattened and slightly curved elements. These observations tended to indicate that in α cells the apical structures were extensions of the apical plasma membrane and thereby might be implicated in sodium uptake when fishes are placed in fresh or deionized water and in chloride excretion when they are transferred to salt water. In β cells, the apical structures were usually separated from the apical plasma membrane by a zone rich in cytoskeleton elements. They penetrated deeply into the supranuclear region, where they intermingled with the elements of the tubular system. They consisted mainly of tubular elements that contained a material resembling that present in the trans tubular Golgi network from which they might originate. The apical structures remained unaltered in β cells whatever the medium (fresh or deionized water) in which the fish was placed.Conclusions: The α cells which are usually thought to be mainly involved in chloride excretion when fishes are transferred into seawater might also be implicated in sodium uptake in freshwater living conditions. The rǒle of β cells, in contrast, still remains to be established. © 1995 Wiley‐Liss, Inc.
Expression of cytokeratin mRNAs in normal human esophageal epithelium
Authors: Viaene A. I. , Baert J. H. 
Published: February 2005

AbstractBackground: The cytokeratin (CK) pattern is accepted to be characteristic of a given epithelial cell or tissue. Specific changes in the CK pattern or in the expression of individual CKs may be characteristic in the early development of particular epithelial pathologies. Up to now no systematic hybridohistochemical study on the expression of CKs in normal human esophageal epithelium has been performed. Nevertheless, this knowledge may be of great importance for further research concerning the understanding of the structure and differentiation of normal esophageal epithelium and of the development of non‐neoplastic and neoplastic esophageal malignancies. Therefore, we investigated the expression and distribution of nine different CK mRNAs throughout the normal human esophageal mucosa.Methods: A non‐radioactive in sity hydridization protocol was used to study the expression of CK mRNAs in fixed and paraffin‐embedded human esophageal mucosa. Digoxigenin‐labelled cRNA probes were produced by in vitro transcription of cDNA clones, coding for human CKs.Results: In situ hybridization and immunodetection of the hybrids revealed a distinct but different distribution pattern for each specific CK mRNA. The described signal pattern was consistently found at all levels of the esophagus. We observed differences in the expression of some CK mRNAs between the interpapillar and papillar compartment of the esophageal epithelium. Mainly in the papillar regions some mRNAs are already expressed in more basally located cells in comparison with the interpapillar regions. Our results substantiate the hypothesis concerning the formation of papillae in the esophageal mucosa. We have also described some observations on the expression of CK mRNAs in fortuitous sections through excretory ducts of esophageal submucosal glands.Conclusions: The distinct, characteristic, and reproducible distribution pattern observed for each specific CK mRNA indicates that the expression of the genes encoding CKs in the esophageal epithelium as well depends on the cell proliferation, on vertical cell migration and differentiation, and on detachment from the basal lamina. The results presented should be considered as complementary to the already existing immunohistochemical results concerning the distribution of esophageal CK proteins. © 1995 Wiley‐Liss, Inc.
Serotonin‐containing projections to the mesencephalic trigeminal nucleus of the cat
Authors: Lazarov Nikolai E. , Chouchkov Christo N. 
Published: February 2005

AbstractBackground: It is well known that the mesencephalic trigeminal nucleus (MTN) neurons transmit somatosensory information from proprioceptors in the oral‐facial region. Several mechanisms of sensory transduction in these specialized receptors have been proposed, but the neurotransmitters which are responsible for mediating proprioceptive information are still unknown. The current study concentrates on the distribution of one putative neurotransmitter system, serotonin (SER), in the cat MTN. A second objective was to clarify the location and sources of serotoninergic projections on the MTN neurons.Methods: To determine whether SER was localized in the MTN, the peroxidase‐antiperoxidase (PAP) immunocytochemical technique was applied at light and electron microscopic levels in colchicine‐treated animals. The origin of SER‐containing fibers in the MTN was studied using a doublelabeling method combining retrograde transport with wheat germ agglutinin conjugated to horseradish peroxidase (WGA‐HRP) and SER immunocytochemistry.Results: There were no SER‐containing neurons in the MTN. The cell bodies of immunonegative MTN neurons were closely surrounded by fine SER‐positive fibers and terminals. The labeled fibers were in most cases very thin and sometimes varicose. Ultrastructurally, direct synaptic contacts between SER‐containing terminals and perikarya of MTN neurons of all sizes could be seen. The majority of SER‐labeled structures were synaptic terminals in which the immunoreactive material was located within the small round clear as well as the small granular vesicles (diameter 50–80 nm) and a few large dense‐cored vesicles (up to 150 nm). Retrograde tracing demonstrated that most of cells in the nuclei raphe dorsalis, pontis and magnus were WGA‐HRP‐labeled.Conclusions: These results indicated that MTN neurons received serotoninergic projections from the raphe nuclei of the brainstem. In light of these morphological data, it is concluded that the MTN of the cat is under the influence of SER‐containing axons and this serotoninergic input may modulate MTN neuronal activity at the first synaptic relay. © 1995 Wiley‐Liss, Inc.
Cellular composition of milky spots in the human greater omentum: An immunochemical and ultrastructural study
Authors: Krist Lambert F. G. , Eestermans Inge L. , Steenbergen Joke J. E. , Hoefsmit Elisabeth C. M. , Cuesta Mihuel A. , Meyer Sybren , Beelen Robert H. J. 
Published: February 2005

AbstractBackground: Milky spots in the greater omentum of some animals are well organized perivascular infiltrated of leucocytes, and are considered to have characteristics of secondary lymphoid tissue. To determine whether milky spots in the human greater omentum can also be regarded as secondary lymphoid tissue, we studied milky spots in an unstimulated state.Methods: Patients were selected on the basis of absence of disease in the peritoneal cavity that might influence the state of the milky spots. Using monoclonel antibodies aganist macrophages, B‐lymphocytes and T‐lymphocytes, and immunoperoxidase labeling, the number of these cells and their location in milky spots were studied by light microscopy. However, the stromal components of the greater omentum, especially those within the milky spots, were studied by electron microscopy.Results: Milky spots in the human greater omentum are relatively uniform vascularized accumulations of mononuclear cells comprising macrophages (67.9% ± 9.4, mean ± standard deviation), B‐cells (10.1% ± 3.4), T‐cells (10.2% ± 3.7), and mast cells. However, no special B‐cells and T‐cell areas could be distinguished. On the ultrastructural level it was demonstrated that macrophages are present in different stages of maturation and can enter or leave the milky spots. Furthermore, no cells characteristic of secondary lymphoid organs, such as interdigitating cells or follicular dendritic cells, were seen.Conclusions: These data indicate that unstimulated milky spots in the human greater omentum are to a great extent just a preformed specific accumulation of primarily macrophages within the stroma of the greater omentum, and therefore, cannot be regarded as true secondary lymphoid tissue. Milky spots could serve as a gateway for, as well as a provider of pertioneal macrophages when the intra‐abdominal status so requires.Finally, the data from this study are compard with the data of other studies of human milky spots and those in animals. © 1995 Wiley‐Liss, Inc.
Distribution of colloidal gold tracer within rat parasternal lymph nodes after intrapleural injection
Authors: Glazyrin A. L. , Kolesnikov S. I. , Dragun G. N. , Zelentsov E. L. , Zolotarev K. V. , Zorin Yu A , Kulipanov G. N. , Gorchakov V. N. , Dolbnya I. P. 
Published: February 2005

AbstractBackground: Tracer studies are a important tool to obtain information about the processes involved in the immunological response. Colloidal gold is widely used as a tracer, but its small size of label can cause some difficulty during low‐resolution analysis. To overcome this difficulty, se developed a new method to follow the route of tracer movement within lymph nodes.Methods: We applied conventional X‐ray analysis, X‐ray flurescence analysis (XFA) subtractional microscop using synchrotron radiation (SR) beam, light mycroscopy, and ultrastructural analysis to study the distribution and quantity of colloidal gold coupled with albumin with rat parasternal lymph node 2, 4, 6, 8, and 10 h after intrapleural injection of the tracer.Results: At all the time points XFA‐SR revealed that racer formed a circle with a maximum concentration in the node periphery. XFA‐SR measured colloidal gold concentration in the nodes reached its maximum (0.5−0.75 weight%) in 6–8 h. Substractional microscopy revealed superficially located groups of cells filled with colloidal gold tracer. Light microscopy and ultrastructural analysis confirmed that the tracer was concentrated in the reticular cells, situated in the sinuses of the node. Sinusoidal reticular cells concentrated tracer at much higher rates than sinusoidal macrophages. Four hours after injection, gold appeared in the lysosmes of the follicular reticular cells. At the same time point, evidence of antigen presentation was obtained. Antigen presentation proved to be an extremel sentation was obtained. Antigen presentation proved to be an extremely rare event since only one ultrastructural incident was found in 150 analysed grids.Conclusion: SR is a valuable tool for the analysis of gold tracer passage with in the living organism. © 1995 Wiley‐Liss, Inc.
Cytoskeleton in sertoli cells of the mosquito fish (Gambusia affinis holbrooki)
Authors: Arenas Maria Isabel , Fraile Benito , De Miguel Maria Paz , Paniagua Richardo 
Published: February 2005

AbstractBackground: There is little information about the distrib ution of cytoskeletal components in the testes of teleost fish. The aim of this (tublin, actin, vimentin, desmin, and cytokeratins) in the sertoli cells of Gambusia affinis holbrooki and in their efferent duct epithelial cells which are possibly orginated from the Sertoli cellsMethods: Light and electron microscopic immunocytochemical studies and Western blotting analysis were performed in G. affinis testis.Results: Actin immuncor eaction was observed in the Sertoli cells at all spermatogenic stages, although the intensity of the reaction varied from one state to another. Sertoli cells that support supermatogonia or supermatocytes showd a weak immunoreaction which was uniformly distributed throughout the cytoplasm and somewhat more concentrated at the level of the inter‐Sertoli specialized junctions, Immunoreaction to actin increased during the first states of supermiogenesis and was manly localized beneath the plasma membrane. This immunoreacction was more intense in the basal than in the aical ctoplasm of Sertoli cells. In a more advanced stage of supermiogenesis, actin immunoreaction become stroger in the apical cytoplasm where Sertoli cells displayed cytoplasmic projections around each supermatid. After sperm release, the apical Sertoli cell cytoplasm still showed an intense actin immunoreaction. Intense immuncreation to actin was also observed in the epithelial cells lining the efferent ducts. Immunoreaction to tubulin was diffuse throughout the Sertoli cell cytoplasm. No immunocreation to vimentin or desmn was observed in the Sertoli cells during the spermatogenic process. Immunoreation to both vimentin and desmin was observed in the efferent ducts cells. Desmin immunoreaction was also observed in the seminiferous tubule boundary cells, mainl in the sections showing germ cell cysts at the last stages of spermiogenesis and in the peritubular cells that surrounded the efferent duct epitheium. Immunoreaction to cytokeratins was found in the endothelium of testicular blood vessels but not in the Sertoli cells or in the efferent duct epithelium.Conclusions: Immunoreaction pattern to cytoskeletal proteins in the Sertoli cells of G. afinis: differs from that reported in mammalian Sertoli cells. These differences include the distribution of action filaments and the absence of dectectable vimentin immunoreaction in G. affinis: Sertoli cells. © 1995 Wiley‐Liss, Inc.