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At least 811 records · Page 45Linked to original sources
PubMed1977

[Studies on the halfside comparison of heterotopic transplantation of mucosa with and without epithelium].

In patients with symmetric recessions in their canine and premolar regions, one side was supplied with an epithelium-containing and the other with an epithelium-free graft from the hard palate. Both sides were studied and compared. After six months, the size of the connective tissue transplants was reduced by 50% (that of the epithelium transplants by 0%). Within half a year, the width of the attached gingiva had decreased by 36% in the case of connective tissue transplants (epithelium transplants by 15%) and the vertical graft width by 60% (epithelium transpltnas 17%). Our clinical and histological findings suggest that grafting of heterotopic connective tissue transplants is not equal to epithelium-containing transplants.

Adolescent↗
PubMed1989

[Reaction of the respiratory tract epithelium to bronchoalveolar lavage].

The authors investigated experimentally the reaction of the airway epithelium to the bronchoalveolar lavage. The epithelium of the rabbit trachea was examined immediately after rinsing with saline and 2, 24, 48 and 72 hours after rinsing. Lavage causes excessive stimulation of goblet cells. Immediately after lavage we find in the epithelium 99% goblet cells which after releasing the secretion degenerate and are gradually expelled from the epithelium. Regeneration of goblet cells begins 24 hours after lavage and is associated with massive differentiation of new goblet cells which leads to hyperplasia of mucus secreting elements and the formation of endoepithelial mucous glands. Signs of pathological alteration of ciliated cells are most marked 2 hours after impairs subsequently the degree of alteration of these cells declines gradually. Bronchoalveolar lavage reduces markedly the ciliary border above the epithelium, the number of kinocilia declines on average to 1.5/microns 2. In the subsequent stages the number of kinocilia increases again to 7.5/microns 2. This value is still significantly lower (p less than 0.005) than in controls. In the impaired ciliary border as a morphological sign of the impaired self-cleaning ability of the airway epithelium, numerous bacteria and condensed mucus are founded. Signs of local disorders of mucus flow are apparent still three days after bronchoalveolar lavage.

Animals↗
PubMed1986

Immunohistochemical identification of Langerhans cells in normal epithelium and in epithelial lesions of the uterine cervix.

Using the double label indirect immunofluorescence technique we have studied vimentin-positive cells present in normal ecto- and endocervical epithelium, subcolumnar reserve cell hyperplasia, and squamous metaplastic and dysplastic epithelium of the uterine cervix. Monoclonal antibodies to Ia- and T6-antigens were applied in the examination of the expression of these membrane markers by such cells. Our studies reveal the presence of a relatively large number of vimentin-positive and T6-positive (Langerhans) cells in normal ectocervical stratified squamous epithelium, a small number in endocervical columnar epithelium, and a larger number in subcolumnar reserve cell hyperplasia and in immature squamous metaplasia. In this respect, mature squamous metaplastic epithelium shows a great resemblance to normal ectocervical stratified squamous epithelium. In contrast with previous reports in the literature we could only demonstrate small numbers of Langerhans cells in cases of dysplasia. The clinicopathological significance of these findings is discussed.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1988

[Architectural ultrastructure of the urinary bladder epithelium. I. The influence of the contracted and distended state].

The luminal surface and three dimensional architecture during contraction and distension of the normal rat and human urinary bladder mucosa were observed by scanning electron microscopy (SEM) after cryofracture of specimen and by transmission electron microscopy (TEM). The bladder epithelium consists of three distinct types of cells, superficial, intermediate and basal cells. SEM and TEM shows that the epithelium is stratified in various states. Some of the intermediate cells reach the basal lamina by fine cytoplasmic processes, but most of them and superficial cells never directly reach the basal lamina. In the rat bladder, the contracted epithelium consists of three to five cell layers and becomes three cell layers in the distended state. Since neighbouring cells are joined by desmosomes, the contact relations between each cell do not change in contracted and distended states. SEM shows an irregular luminal surface of the superficial cells in contracted state. Under TEM this luminal surface showed a scalloped contour, and most of the cell membranes intruding into the cytoplasm gave the appearance of discoidal vesicles. Between superficial cells there are numerous interdigitations in the distended state which show an accordion-like appearance. Between neighbouring cell layers the interdigitations are deep in the contracted state and shallow in the distended state. In the human bladder, the contracted epithelium consists of six to eight cell layers and becomes three to six cell layers on the distended state. Ultrastructural features of the human bladder epithelium during contraction and distension are basically similar to those of the rat bladder epithelium. In contrast, during contraction and distension mainly cellular shape changes from protruded to flattened, but the microvilli-like membrane junctions between intermediate and basal cell layers demonstrate little change.

Animals↗
PubMed1986

Con A- and WGA-binding glycoproteins of stationary and migratory corneal epithelium.

When stratified corneal rat epithelium becomes migratory in response to a wound, an increase in binding by the lectins concanavalin A (Con A) and wheat germ agglutinin (WGA) is seen. These lectins bind the membranes of the cells of the leading edge of the migrating sheet more intensely than normal epithelium and epithelium behind the leading edge, suggesting a change in cell surface properties during migration. In the present study, analysis of cell surface proteins using lactoperoxidase-catalyzed iodination followed by SDS-PAGE indicates the appearance of a 70 K protein in epithelium migrating to cover a wound. Con A-affinity chromatography shows that two bands, 70 K and 155 K, increase 4.0- and 2.9-fold, respectively, in epithelium that is migrating. WGA-binding glycoproteins increased 1.61-fold following wounding with the major band present at 155 K in SDS-PAGE. The data suggest that these glycoproteins are responsible for the increase in Con A and WGA binding to cell membranes in migratory corneal epithelium.

Animals↗
PubMed1978

[Differentiation of the endodermal epithelium associated with the splanchnic mesoderm].

Allantoic epithelium and epithelium from different levels of the digestive tube of the guail embryo were grafted into chick embryo splanchnopleure so that these epitheliums would come into contact with the mesoderm of the developing host digestive tube at a variety of levels. Under these conditions, the allantoic epithelium develops into an epithelium corresponding to the level of the digestive tube at which it was grafted. By contrast, the presumptive fate of epithelium from the small intestine is not modified by the mesenchyme with which it becomes associated. Mesenchyme from the small intestine, on the other hand, always dictates the type of differentiation in epithelial grafts from other levels of the digestive tube.

Allantois↗
PubMed1983

Androgens and estrogens: their interaction with stroma and epithelium of human benign prostatic hyperplasia and normal prostate.

Growth and integrity of human prostatic epithelium is strongly dependent upon the adjacent stroma. Furthermore, the human prostate is under the control of sex hormones. Both facts prompted us to compare epithelium with stroma of human benign prostatic hyperplasia (BPH) and normal prostate (NPR) concerning their metabolism, binding and tissue concentrations of androgens and estrogens. In vitro metabolism was analyzed by t.l.c., androgen and estrogen binding sites were determined by a charcoal adsorption technique, androgen and estrogen tissue concentrations were measured by RIA. The main results are--(1) Metabolism: BPH stroma shows 2-3 times higher 5 alpha-reductase activity than epithelium. This high 5 alpha-reductase activity in BPH stroma dictates the differences between unseparated BPH and NPR, in the former the 5 alpha-reductase activity being 2 times higher. The 3 alpha(beta)-hydroxysteroid dehydrogenase (HSDH) activity is more evenly distributed between stroma and epithelium of BPH and NPR. The ratios of 5 alpha-reductase to HSDH activity in the various tissue fractions indicate that the highest enzymatically regulated 5 alpha-dihydrotestosterone (DHT) enrichment must occur in BPH stroma. (2) Tissue concentrations: unseparated BPH contains 2.2 times more DHT than NPR. About 70% of the total DHT content is found in nuclear fractions, whereby the nuclear DHT content of BPH stroma is significantly higher than that of BPH epithelium. In addition, nuclei of BPH stroma contain significantly more estradiol than epithelial nuclei. (3) Binding: the androgen receptor is evenly distributed between epithelium and stroma of BPH, while the estrogen receptor is preferably assayed in BPH stroma. These studies indicate that the BPH stroma is not only a preferential tissue for 5 alpha-reductase activity and DHT enrichment but also for nuclear estradiol accumulation.

3-Hydroxysteroid Dehydrogenases↗
PubMed1983

Regeneration of cervical epithelium after laser vaporization.

The process of reepithelialization after laser vaporization of normal cervical squamous epithelium was examined using light and electron microscopy. Tissue specimens were obtained from seven patients at time intervals ranging from seven to 16 days after laser vaporization. Immature squamous epithelium appeared at the edge of the laser crater between seven and 14 days, and by 14 to 16 days, the immature epithelium covered the entire crater area. The observations made in this study concur with those of other studies of the healing process of squamous epithelium, whereby immature cells from the surrounding undamaged epithelium migrate into the damaged area, eventually differentiating into a full thickness of epithelium.

Biopsy↗
PubMedDate not supplied

[Potentials for crystalline lens development in the corneal epithelium of Rana temporaria tadpoles].

The lens-forming potencies of the corneal epithelium were studied in the Rana temporaria tadpoles. The corneal epithelium isolated from the tadpoles at the 31st-39th developmental stages was implanted in the vitreous body cavity of lens-less eyes of the tadpoles of the same species. At the 31st-32nd stages the corneal epithelium is in direct contact with the lens which was separated by means of dissociating agents. The corneal epithelium has lens-forming potencies and preserves them till stage 39 when such potencies are rapidly lost. The data obtained allow to suggest the relative autonomy of the loss of lens-forming potencies by the corneal epithelium. The causes of wide distribution of lens-forming potencies in the corneal epithelium of different animal species are discussed.

Animals↗
PubMed1982

[Effects of X-irradiation on cell kinetics of oral epithelium in mice (author's transl)].

The acute radiation effects on the tongue and lip mucosa epithelium were cytokinetically investigated after the local irradiation at the head part of C3Hf/He mice with single dose of 516 mC/kg (2000R) of X rays. The microautoradiographic study was performed for these two kinds of oral epithelium at various times after the pulse-labeling with 3H-thymidine, which followed immediately after the irradiation. The cell kinetics of irradiated as well as unirradiated basal cells were investigated by observing the changes in frequencies of the labeled cells and the labeled mitoses in the epithelium along the time course after irradiation. The results of the analysis of the percent frequencies of mitotic cells as a function of time after the labeling and the irradiation showed that the movement of the labeled cells were blocked at G2 phase for about 6 hr and that the cell cycle time after the 1st post irradiation mitoses became shorter than that of the unirradiated cells. However, no change was found in the migration rate of the tongue epithelium, i.e., the time required for labeled cells to migrate from basal cell layer to prickle-granular cell layer. On the other hand, only 25% of labeled cells in the lip mucosa epithelium migrated into prickle-granular cell layer until 40 hr after irradiation, and it was hardly observed that the labeled cells moved into mitotic phase. These results suggest that basal cell of the lip mucosa is more radiosensitive than that of the tongue epithelium.

Animals↗
PubMed1980

Ultrastructure of terminal respiratory epithelium and prognosis in chronic interstitial pneumonia.

Following acute damage, proliferation of granular pneumocytes with subsequent transformation into membranous cells is the basic pattern of repair of the alveolar epithelium. Regarding chronic interstitial pneumonias little is known about the ultrastructural changes of terminal respiratory epithelium and their clinical significance. We studied open lung biopsies from 10 patients showing clinical and light microscopic changes consistent with chronic idiopathic interstitial pneumonia (UIP). We studied the ultrastructure and correlated it with the clinical course of the patients. Only alveolar type epithelium was seen in two cases with a short duration of disease and good response to therapy. Bronchiolar-type epithelium was present in the terminal respiratory units of all other patients with longer duration of disease and less favourable prognosis. Four patients died: all of them showed signs of mucus secretion and keratinization in the terminal respiratory epithelium. Thus in chronic interstitial pneumonia the presence of the alveolar type of epithelium seems to indicate reversibility and that of the bronchiolar type irreversibility of the lesions, while mucous and keratinizing metaplasias apparently occur at a late stage of the disease.

Adult↗
PubMedDate not supplied

[An analysis of keratin expression in the cells of the retinal pigment epithelium during transdifferentiation in newts].

Keratins of the cytoskeletal intermediate filaments have been identified immunohistochemically in pigment epithelium cells of the adult newt retina. We studied the expression of keratins in transdifferentiating and redifferentiating cells of the retinal pigment epithelium at different periods after removal of the retina. We have shown that the expression of keratins decreases. This appears as the decreased intensity of the immunospecific reaction soon after the operation. The latter observation has also been made immediately after artificial dissociation of the pigment epithelium cells of the retina isolated from nonoperated newt eyes. We found that the immunostaining of keratins was absent in the cells of normal and regenerating retina, as well as in retinal pigment epithelium cells before restoration of their structural and functional relationship with the retinal regenerate. The results obtained provide evidence for the inhibition of keratins expression during the transformation of retinal pigment epithelium into the retina. We proposed that there exists a mechanism responsible for gradual replacement of keratins by proteins of neurofilaments that have earlier been identified at the beginning of transdifferentiation of the retinal pigment epithelium.

Animals↗
PubMed1994

Influence of epithelium removal on allergic contraction of isolated tracheal smooth muscle.

Sensitized guinea pig tracheal preparations with epithelium removed were more sensitive to acetylcholine, histamine substance P, and barium chloride than those with epithelium intact. EC50 of them obtained in the preparations with epithelium removed dramatically decreased to 1/6-1/30 vs that obtained in epithelium intact ones. The amplitudes of contractions of epithelium-removed preparations induced by antigen-antibody reaction or electric field stimulation increased by 50%-100% vs the control. These results indicated that the epithelium had important modulative effects on the airway, especially on its allergic contractions.

Acetylcholine↗
PubMed1995

Expression and localization of CFTR in the rhesus monkey surface airway epithelium.

The Rhesus monkey has been used as a model for evaluating the possibility of introducing the CFTR gene into the airway epithelium in vivo. We addressed the question of whether the simian airway surface epithelium exhibits a CFTR distribution and functional activity (ciliary beating frequency) similar to that of human airway surface epithelium. Expression of CFTR mRNA was demonstrated on Rhesus monkey tracheobronchial tissue by reverse transcription polymerase chain reaction (RT-PCR) analysis. By immunofluorescent light microscopy, CFTR was localized on the apical plasma membrane of ciliated cells as we previously described for human tracheobronchial surface epithelium. The ciliary beat frequency (CBF) measured on the explant of Rhesus monkey tracheobronchial tissue appeared to be similar to that of the CBF of human tracheobronchial ciliated cells. To compare the Rhesus monkey CFTR gene with that of the human, we sequenced parts of exon 13 (encoding the R domain) and exon 24 (encoding the C terminal part of the protein) of the Rhesus monkey CFTR gene. The nucleotide sequence identity with the human counterpart was found to be 98% and 94% respectively, although restriction enzyme differences allow discrimination between Rhesus monkey and human CFTR cDNA. Taken together, these results suggest that the airway epithelium of the Rhesus monkey is a suitable model of human respiratory epithelium for analyzing the effect of human CFTR gene transfer.

Amino Acid Sequence↗
PubMed1995

Cellular localization of thrombomodulin in human epithelium and squamous malignancies.

Thrombomodulin is a cell surface glycoprotein that functions as an anticoagulant. Although initially identified on endothelial cells, thrombomodulin is also expressed by other vascular cells, by mesothelial cells, and by epidermal keratinocytes. To determine whether thrombomodulin is expressed by epithelial cells in locations other than skin, we conducted a survey of thrombomodulin protein and mRNA in human epithelium. Thrombomodulin protein was detected by immunohistochemistry in all samples containing stratified squamous epithelium, including oral mucosa, larynx, esophagus, uterine ectocervix, and vagina. In these tissues, thrombomodulin staining localized to the suprabasal layer, with minimal staining observed in the basal or superficial layers of epithelium. Thrombomodulin was not detected in cuboidal, simple columnar, or pseudostratified columnar epithelium and was detected variably in transitional epithelium. Thrombomodulin staining was also observed in 21 of 26 cases of invasive squamous cell carcinoma and in several examples of squamous carcinoma-in-situ and squamous metaplasia. Expression of thrombomodulin mRNA was confirmed by in situ hybridization in both normal and malignant squamous epithelium. Full-length, functionally active thrombomodulin was demonstrated in cultured squamous epithelial cells. These data demonstrate that thrombomodulin expression correlates with the squamous phenotype and suggest that hemostasis is regulated by compartmentalization of procoagulant and anti-coagulant epithelial proteins.

Blotting, Northern↗
PubMedDate not supplied

[A comparison of the differentiation of tumor cells and of the epithelium of the gastric mucosa in cancer].

The correlation between differentiation of tumor cells in different directions (toward the foveolate epithelium or glandular epithelium in stomach, or small and large intestine epithelium, or endocrine cells) and the state of gastric mucosa (differentiation of its cells in direction of foveolate epithelium or glandular epithelium (hypoplasia of corresponding epithelium), or appearance of focals of metaplasia in small or large intestines, or pronounced hyperplasia of endocrine cells) was revealed in most cases of gastric cancer. The other of the disease did not reveal such correlation.

Adenocarcinoma↗
PubMed1994

Transdifferentiation of pigmented multipotent epithelium during morphallactic development of budding tunicates.

In the budding tunicate, Polyandrocarpa misakiensis, the atrial epithelium is the major formative tissue giving rise to the pharynx, digestive tract, brain and endostyle of a bud. We show here that this multipotent epithelium carries several differentiation markers that are lost in the process of bud development. In both adult animals and growing buds, the atrial epithelium contained orange-pigmented granules in the cytoplasm. In developing buds, on the other hand, the cells committed to organ primordia have lost the granules, taken a cuboidal shape and have a large nucleus with a prominent nucleolus, like undifferentiated cells. The atrial epithelium was also characterized by ALP expressed on the apical surface of the cell. During budding the enzyme activity disappeared from the atrial epithelium and reappeared in the primordial digestive tract. Immunohistochemical studies suggested strongly that during gut formation, ALP antigens has been switched from the epithelial isoform to the intestinal isoform. These results have shown that in P. misakiensis budding involves transdifferentiation of multipotent, but differentiated epithelium, confirming our previous results (Fujiwara and Kawamura, Dev. Growth Differ. 34:463-472, 1992).

Alkaline Phosphatase↗
PubMed1996

Class II MHC antigen (Ia)-bearing dendritic cells in the epithelium of the rat intestine.

Many tissues are found to contain populations of cells with an unusual dendritic shape, high levels of surface expression of MHC class II (Ia) gene products, and strong accessory function for the stimulation of specific clones of quiescent T lymphocytes. Dendritic cells (DC) represent major population of "professional" APC in various lymphoid and nonlymphoid tissues, distinct from cells of the monocyte/macrophage lineage. Among the best characterized nonlymphoid dendritic cells are epidermal Langerhans cells, but it has been shown that interstitium and epithelium of other organs also contain irregularly shaped, strongly MHC class II positive cells. In recent years, DC have been localized to alveolar septa in the lung, as well as within and just beneath airway epithelium, comprising a tightly meshed network that is reminiscent of epidermal Langerhans cells. In the gastrointestinal tract, conventional immunohistochemical analysis of mucosal class II MHC (Ia) staining reveals a morphologically heterogeneous pattern of staining in the lamina propria. DC that exhibit strong Ag-presenting activity in vitro have been extracted from enzymatic digests of colonic mucosa, but no previous reports of MHC class II-positive cells with pleiomorphic morphology have been recorded within the epithelium of the intestine. Employing a novel combination of nonconventional section planes, pre-embedding fixation, and immunohistochemical techniques, we now demonstrate Ia staining of cells with classical DC morphology within the epithelium of the intestine in normal specific pathogen-free rats. Our investigation suggests that cells with the morphologic and phenotypical characteristics of DC are present within the mucosal epithelium of the rat jejunum and colon, comprising a significant organized network. The number of DC within epithelium of the colon was 117 +/- 20 per 10-microns-thick cross-section. These findings have important theoretical implications for research on Ag processing and T cell activation in the context of allergic and infectious diseases in the gastrointestinal tract.

Animals↗