摘要:

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

ISSN:0003-276X    

DOI:10.1002/ar.1092410112

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: A previous study of piglet lung growth (Mansell et. al. 1989. J. Appl. Physiol., 67:1422–1427) showed transient stiffness to changes in shape and volume immediately after birth. Later, elastic recoil was found to increase as the lung grew in weight and volume. The present study uses morphometry to test possible structural correlates of these two mechanical changes.Methods: Piglet lungs were fixed near full inflation via the airways during the immediate newborn period (6–12 hours, n=3), at 3–5 days (n=6), 25–30 days (n=5), and 80–85 days (n=3). Morphometry comprised arithmetic and harmonic mean thicknesses of alveolar septae and average mean surface curvature. Measurements of curvature and airspace volume were combined to differentiate alveolar expansion from septal proliferation as mechanisms for volumetric growth.Results: The unique mechanical behavior of the newborn lungs was associated with relatively thick alveolar septae. Marked thinning of the septae and resolution of the stiffness to shape and volume change had occurred by 3–5 days. An increase in elastic recoil during the first postnatal month was found to be associated with simple airspace expansion. The second and third months were characterized by septal proliferation and increase in arithmetic mean septal thickness but elastic recoil did not increase further. Harmonic mean septal thickness and airspace volume per gram of lung tissue did not change over the course of the study.Conclusions: 1) A relative stiffness to shape and volume change in freshly newborn piglet lung is associated with relatively thick alveolar septal walls; 2) postnatal development of piglet lung parenchyma involves septal lengthening and thinning followed by septal proliferation; 3) the initial phase of septal lengthening, rather than the later phase of septal proliferation, is associated with increase in parenchymal recoil. © 1995 Wil

ISSN:0003-276X    

DOI:10.1002/ar.1092410113

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: The objective of the present study is to investigate the migration pattern of the splenic dendritic cell of the chicken named the ellipsoid‐associated cell (EAC) from the site of initial location at the periphery of the ellipsoid to the splenic T‐ and B‐dependent areas.Methods: Bovine serum albumin bound to biotin and conjugated to gold particles was used as a histochemically identifiable antigen detected as a peroxidase reaction. The antigen was intravenously injected, and subsequently its pattern of distribution in a time sequence and within the tissue was examined at the light and electron microsocopy levels. In addition, an hour prior to sacrifice, the chickens received a single injection of the thymidine analogue 5‐bromo‐2′‐deoxyuridine, in order to quantify the number of DNA synthesizing cells and to establish a relationship between the migrating EAC and the rate of mitosis in the white pulp.Results: The observations showed that between 12 hours and 3 days after the second antigen administration the labeled EAC, which was first located around the ellipsoid, progressively reached further areas with time towards the periarteriolar lymphoid sheaths, where newly formed germinal centers appeared. Furthermore, the rate of cell proliferation within the white pulp was associated with the arrival of the antigen‐transporting EAC.Conclusions: The results suggest that migrating EAC have a role as both antigen‐transporting cell and antigen‐presenting cell in the T‐ and B‐dependent areas, as a result of which migrating EAC is transiently found in periellipsoidal white pulp, then periarteriolar lymphoid sheaths, and finally germinal centers, where it may function as an interdigitating cell or as a follicular dendritic cell, depending on its location. Thus, we conclude that the EACs are precursors of both interdigitating and follicular dendritic cells.

ISSN:0003-276X    

DOI:10.1002/ar.1092410114

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: The reticular framework in the lymph node has in the past been studied mainly by light microscopy of silver‐impregnated specimens. The aim of the present study is to understand three‐dimensionally the ultrastructure and organization of the reticular framework better than before.Methods: The mesenteric lymph nodes of the rat were prepared either an alkali‐water maceration method or a conventional method and were observed in a scanning electron microscope (SEM).Results: The SEM study of alkali‐water macerated tissues visualized directly the reticular fiber network in the lymph node. The reticular fibers consisted of thin bundles of collagem fibrils. They were continuous with the collagen fibriliar sheaths of blood vessels and lymphatic sinuses as well as with the fibrous capusule, thus acting as a skeleton of the lymph node. The arrangement of the reticulum was variable, depending on individual compartments. The SEM study of conventionally treated tissues, on the other hand, clarified the shape of reticular cells and their relationship with the reticular fibers. The sinus reticular cells connected with the sinus lining cells but separated from the parenchymal reticular cells, indicating that the former two originate from lymphatic endothelial cells. The parenchymal reticular cells varied in shape depending on their locations but essentially shared features with fibroblasts.Conclusions: The arrangements of the reticular fibers in the parenchyma were closely related to the associated reticular cells, showing the possibility that the reticular cells maintain the shape of the reticular framework suitable for each compartment of the lymph node. © 1995 Wiley

ISSN:0003-276X    

DOI:10.1002/ar.1092410115

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: It is known that while denervated skeletal muscles have the ability to regenerate, maturation of regenerated myofibres does not take place under these conditions. Denervation also causes elevation of “invasive” and satellite cells, but the role of these cells in the regeneration process after injury to the denervated muscle is still unknown. Low energy lasers have recently been found to modulate and accelerate physiological processes in cells. The aim of the present study was to compare regeneration in denervated and innervated amphibian muscles and to investigate whether this process in denervated muscles can be stimulated by low energy laser irradiation prior to injury in these muscles.Methods: Denervated gastrocnemius muscles of toads were irradiated with He‐Ne laser (6.0 mW, 31.2 J/cm2) 7 days postdenervation (control muscle received red light irradiation at the same wavelength). Nine days after denervation cold injury was performed on the site of irradiation of both groups of muscles. At 14 days postinjury all muscles were removed and processed for histology and histomorphometric analysis of mononucleated cells, myotubes, and young myofibres in the regenerated zone.Results: The volume fraction (percent of total injured zone) of the various histological structures in the injured zones 14 days after cold injury in the denervated (9 days prior to injury) muscles did not differ from innervated injured muscles at the same time interval postinjury. The mononucleated cells and myotubes in the laser irradiated muscles comprised 49 ± 4% and 6 plusmn; 1% of the injured area, respectively, which was significantly lower than their volume fraction (67 plusmn; 2% and 11 plusmn; 2%, respectively) in the control muscles. The young myofibres populated 34 plusmn; 4% of the total injured area in the denervated and laser irradiated muscles which was significantly higher than their volume fraction (12 ± 2%) in control denervated muscles.Conclusions: It is concluded that initial stages of regeneration can also take place in skeletal denervated and injured muscles of amphibians. The kinetics of the regeneration process are identical in denervated and innervated muscles. The process of regeneration in denervated muscles can be markedly enhanced if the muscle is irradiated by low energy laser prior to injury, probably by activation (stimulation of proliferation and/or differentiation) cells in the muscles that are “recruited” and participate in the process of regeneration. © 1995 Wil

ISSN:0003-276X    

DOI:10.1002/ar.1092410116

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractAbstract: In this paper we describe the light and electron microscopic appearance of the embryonic type of fat in human infant breast, together with immunocytochemical findings. This fat tissue was composed of numerous capillaries surrounded by a mixed population of undifferentiated mesenchymal cells and preadipocytes at various stages of differentiation. The preadipocytes were characterised by a number of cytoplasmic processes, varying numbers of lipid droplets, and an envelope of electrondense material outside the cell membrane. Immunocytochemistry showed a characteristic distribution of collagen type IV adjacent to and vimentin and S100 protein within the preadipocytes. This is the first report of the ultrastructure of the human mammary embryonic type of fat. The possible role of the embryonic type of fat in the development and growth of the human breast is discussed. © Wiley‐Liss, I

ISSN:0003-276X    

DOI:10.1002/ar.1092410117

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

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 re

ISSN:0003-276X    

DOI:10.1002/ar.1092410118

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1092410119

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1092410101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY