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PubMed1981

Secretory component of IgA: a marker for differentiation of ocular epithelium.

Secretory component (SC) was studied by indirect immunofluorescence of the ocular surface epithelium. We find that conjunctival epithelium produces this component, and that it is absent in the corneal epithelium. Conjunctival epithelium loses its SC staining within 1 to 2 days as it grows over a denuded corneal stroma. This implies a very rapid turn-off of the SC gene and rapid export of the gene product previously formed. However, conjunctival flap epithelium does not change its characteristic structure or functions. Vascularization of corneas resurfaced by conjunctival epithelium usually leads to a rapid reversal of both morphological and biochemical characteristics in the surface epithelium, as judged by the reappearance of goblet cells and positive staining for SC. Vascularization of normal corneas leaves the epithelium unchanged, so that neither goblet cells nor SC appear. Thus metaplasia of conjunctival to corneal epithelium is incomplete, permitting reversion to type under certain conditions.

Animals↗
PubMed2005

Early results of penetrating keratoplasty after cultivated limbal epithelium transplantation.

OBJECTIVE: To describe the early results of penetrating keratoplasty (PKP) in patients who had previously undergone cultivated limbal epithelium transplantation. METHODS: Medical records of patients with limbal stem cell deficiency due to chemical burns who underwent PKP after cultivated limbal epithelium transplantation were reviewed for demographics, primary etiology, type of limbal transplantation, ocular surface stability, visual acuity, graft clarity, and complications. Histopathologic features of the recipient corneal buttons were studied with special attention to epithelial status. RESULTS: Of the 125 patients with limbal stem cell deficiency treated with cultivated limbal epithelium transplantation, 15 underwent PKP at a mean interval of 7 months (range, 2-12 months) following cultivated limbal epithelium transplantation (autologous, n = 11; allogenic, n = 4). All 4 patients treated with allogenic cultivated limbal epithelium transplantation were undergoing immunosuppressive therapy. Fourteen (93%) of the 15 eyes had a successful corneal graft with a stable corneal epithelium. Preoperative best-corrected visual acuity was less than 20/200 in 14 of the 15 eyes. At a mean +/- SD follow-up of 8.3 +/- 5.0 months after PKP, the best-corrected visual acuity was more than 20/60 in 8 eyes, 20/200 to 20/60 in 5 eyes, and less than 20/200 in 2 eyes. Three of the 15 eyes experienced corneal allograft rejection, which was managed successfully. One eye with graft rejection also had glaucoma. None of the limbal epithelial allografts showed signs of rejection. CONCLUSIONS: Early results of PKP following cultivated limbal epithelium transplantation are favorable when performed after stabilizing the ocular surface. Adequate immunosuppression is essential for allogenic cultivated limbal epithelium transplantation to avoid rejection. Corneal allografts can separately reject the limbal allografts.

Adolescent↗
PubMed1999

Role of Bcl-xL protein in differentiation and apoptosis of human middle ear cholesteatoma epithelium.

OBJECTIVE: To compare the mechanisms of proliferation, differentiation, and apoptosis in middle ear cholesteatoma epithelium with those of normal external ear canal epithelium. DESIGN: The localizations of the expression of Bcl-xL protein and involucrin and the presence of apoptotic cells were determined for tissue slices of middle ear cholesteatoma epithelium and compared with the findings for normal external ear canal epithelium. In addition, SCC-25/bcl-xL transfectants showing the overexpression of Bcl-xL were used to investigate the effect of this protein on the expression of involucrin, which is a marker of epithelial cell differentiation. MATERIALS: Cholesteatoma tissue specimens were surgically excised from 10 patients. Normal skin specimens collected from the external ear canal of the 10 patients were used as control specimens. RESULTS: The expression of Bcl-xL was detected in the vicinity of the basal cell layer of both the cholesteatoma epithelium and the normal external ear canal epithelium. Conversely, the expression of involucrin (ie, a marker of epithelial cell differentiation) increased in proportion to the shallowness of the epithelial layer. In situ labeling detected apoptotic cells in the spinous and granular cell layers of cholesteatoma tissue sections and similar findings in the normal external skin specimens. Western blot analysis confirmed that the expression of involucrin protein was the same in both wild-type SCC-25 cells and the SCC-25/bcl-xL transfectants. CONCLUSIONS: In both the cholesteatoma epithelium and the normal external ear canal epithelium, differentiation and apoptosis begin when the epithelial cells separate from the basal cells. The mechanisms behind these changes, at least in apoptosis, appear to be controlled by the expression of the Bcl-xL protein.

Adult↗
PubMed1996

Mouse embryonic submandibular gland epithelium loses its tissue integrity during early branching morphogenesis.

During the development of the mouse submandibular gland, the epithelium undergoes not only shape changes to produce extensively branched lobules and stalk, but also changes in cell arrangement from a cell mass to a cavitated cell sheet. The present study examined the organization in the developing epithelium of intercellular adhesion systems and of actin-containing microfilaments. E-cadherin and beta-catenin, which are components of cell-to-cell adherens junctions in epithelial cells, were distributed along the cell periphery of almost the entire epithelium of the submandibular gland at all stages examined and were mainly localized at the apical region of the oral epithelium. Actin-containing microfilaments, which are associated with cell-to-cell adherens junctions, showed a distribution similar to that of those molecules. In contrast, although the distributions of desmoplakins I/II, major desmosomal proteins, and ZO-1 (a tight junction protein) were seen in the oral epithelium and proximal stalk of the submandibular gland epithelium, signals representing these molecules were absent from or much reduced in the submandibular gland epithelium of the cell mass at the 12- and 13-day stages. In the 14-day gland, they strongly appeared in the cells facing the appearing lumens, whereas they were weakly scattered within the terminal lobules that were still a part of the cell mass. These findings suggest that cell-to-cell adhesion systems are differentially regulated during the epithelial morphogenesis of the submandibular gland and that the integrity of the submandibular gland epithelium is lost during the early stages of development, indicating the tissue to be a rather plastic structure.

Actins↗
PubMed1998

Odontogenic epithelium induces similar molecular responses in chick and mouse mandibular mesenchyme.

Previous observations have shown that, during the initiation phase of odontogenesis, signals from mouse odontogenic epithelium can elicit teeth in non-odontogenic but neural crest-derived mesenchyme isolated from ectopic sites including chick mandibular mesenchyme. In the present study the formation of ectopic tooth buds and dental mesenchyme in chick mandibular mesenchyme was examined using heterospecific recombinations between E11 mouse odontogenic epithelium and stage 23 chick lateral mandibular mesenchyme. Both morphological criteria and chick-specific probes for Msx-1, Msx-2, and Bmp-4 mRNAs were used as markers for early dental mesenchyme. Our results demonstrated that interactions of mouse odontogenic epithelium with chick mandibular mesenchyme induce early changes in the chick mandibular mesenchyme including the appearance of a translucent zone, cell proliferation, and induction of expression of Msx-1, Msx-2, and Bmp-4, which have been shown to be associated with the formation of dental mesenchyme. In addition, tooth bud-like structures that resemble E13 tooth buds in vivo both morphologically and in their patterns of gene expression formed after 6 days in the heterospecific recombinations. The tooth bud-like structures consist of invaginated mouse mandibular epithelium and condensed chick mandibular mesenchyme expressing high levels of Msx-1 and Bmp-4, but undetectable levels of Msx-2. Unlike the induction of Msx-1, Msx-2, and Bmp-4 in the underlying mesenchyme, which is specific for signals derived from odontogenic epithelium, the induction of a translucent zone and cellular proliferation in the underlying mesenchyme may be related to the growth-promoting potential of embryonic epithelia and not be specific to signals derived from the odontogenic epithelium. Similar to mouse odontogenic epithelium, agarose beads soaked in recombinant BMP-4 induced a translucent zone, cellular proliferation, and expression of Msx-1, Msx-2, and Bmp-4 in chick mandibular mesenchyme after 24 hours. These observations together showed that avian mandibular mesenchyme has odontogenic potential that is expressed upon interactions with inductive signals from mouse odontogenic epithelium. Similar to odontogenesis in vivo, formation of dental mesenchyme in chick mandibular mesenchyme is mediated by the activation of Msx-1, Msx-2, and Bmp-4.

Animals↗
PubMed1996

Ultrastructural study of the dorsal lingual epithelium of the soft-shell turtle, Trionyx cartilagineus (Chelonia, Trionychidae).

BACKGROUND: The soft-shell turtle, Trionyx cartilagineus, is classified phylogenetically to the family Trionychidae, whose members live in small rivers or ponds. The purpose of the present study was to examine the ultrastructure of the dorsal epithelium of the tongue of the soft-shell turtle and to compare the results of the observations with those reported for the tongue of other freshwater turtles. METHODS: Light microscopy, transmission electron microscopy, and scanning electron microscopy were used to examine the dorsal epithelium of the tongue of the soft-shell turtle. RESULTS: The tongue is triangular with a slightly round apex when viewed dorsally but it appears flattened when viewed laterally. Lingual papillae were visible on the dorsal surface of the tongue with some localized variations. Irregular, dome-shaped or ridge-like papillae were observed on the anterior part of the dorsal lingual surface. Large, cylindrical papillae were located along the midline of the posterior part of the tongue. Low, disk-like papillae were located on both sides of the dorsal surface of the posterior part of the tongue. Taste pores were recognizable in the center of the disk-like papillae. At higher magnification, scanning electron microscopy revealed microridges on the surface of cells located on the outermost side of the anterior part of the tongue, and the thickenings of cell margins were clearly seen. Microvilli were distributed compactly over the entire posterior part of the tongue. Light microscopy revealed that the mucosal epithelium of the anterior part of the tongue was of the keratinized, stratified squamous type, while the mucosal epithelium of the posterior part of the tongue was of the nonkeratinized, stratified cuboidal type. In the latero-posterior part of the tongue, taste buds were recognized. Transmission electron microscopy revealed that the epithelium of the anterior part of the tongue was of a typical keratinized type. Small numbers of keratohyalin granules and membrane-coating granules appeared in the cytoplasm of the shallow intermediate layer. On the apical side of the lingual papillae located on the posterior side of the tongue, cells from the intermediate layer to the surface layer of the non-keratinized epithelium contained many fine, discoidal granules. A large part of the epithelium consisted of mucous cells in the concave area on the posterior side. CONCLUSIONS: The dorsal surface and epithelium of the tongue of the soft-shell turtle differed significantly from those of other freshwater turtles, in spite of the similarity in terms of gross morphology among the tongues of such turtles.

Animals↗
PubMed2001

Development of the follicle-associated epithelium and the secretory dendritic cell in the bursa of fabricius of the guinea fowl (Numida meleagris) studied by novel monoclonal antibodies.

Two stromal elements, follicle-associated epithelium and secretory dendritic cells of the bursa of Fabricius were studied by light microscopy and two novel MAbs, that were produced against splenic cell suspensions of guinea fowls. Both antigens recognized by these MAbs, designated GIIF3 and NIC2, are localized in the cytoplasm of the stromal cells, and their molecular weights are 50 and 30 kD, respectively. During embryogenesis the GIIF3 and NIC2 cells emerge in the mesenchyme of the folds before follicle formation. The GIIF3 and the NIC2-positive cells accumulate under the surface epithelium of the plicae and migrate into the epithelium, that precedes the bud-formation. From the bud, the GIIF3-positive cells migrate up to the luminal surface, and they transform to distinct, highly polarized follicle-associated epithelial cells. Single GIIF3-positive cells are also present in the interfollicular epithelium. The NIC2 MAb recognized mesenchymal cells harbor in the lymphoepithelial compartment of the folliculus, and they elaborate cytoplasmic granules. Around Day 20 of embryogenesis large amount of NIC2-positive substance appear extracellularly in the medulla and around it. This period well correlates with the starting up of the bursal functions; clonal expansion of B cells, and generation of immune repertoire. After hatching the NIC2 stainability diminishes, and it is restricted to the medullary bursal secretory dendritic cells. The NIC2-positive, possibly elderly bursal secretory dendritic cells, are capable for migration into the follicle-associated epithelium. In eight-day old birds some cells of the follicle-associated epithelium reveals temporary NIC2 positivity, that may prove the transport of the follicle-associated epithelial cells into luminal direction. By 12 weeks of age the presence of NIC2-positive substance in the intercellular space of the FAE, rather than in the cells of FAE may indicate the termination of the transport of secretory substance. In conclusion, two types of mesenchymal cells enter the surface epithelium of the bursal folds. The GIIF3-positive cells appear on the luminal surface of the follicles and occupy the place of the follicle-associated epithelial cells. The NIC2-positive cells become secretory in nature and differentiate to bursal secretory dendritic cells. The follicle formation possibly, requires the joint presence of both GIIF3 and NIC2 cells in the epithelium.

Animals↗
PubMed1982

The pelvic epithelium of the rat kidney: a scanning and transmission electron microscopic study.

The renal pelvis of the rat is characterized by extensions called specialized fornices that penetrate into the outer zone of the outer medulla (a type II as classified by Pfeiffer, 1968, 1970). The renal pelvic epithelium, therefore, covers areas of the kidney from the inner medulla, the inner and outer stripe of the outer medulla, and the cortex. The renal pelves of seven rats were studied by transmission and scanning electron microscopy. The transitional epithelium on the nonparenchymal surface of the pelvis was three to four cell layers thick (zone 0-1). This epithelium became thinner where it covered the renal cortex (zone 1-2) or the outer medulla. Although the apical cells of the epithelium retained the asymmetric luminal unit-membrane plaques, the number of cytoplasmic fusiform vesicles decreased as one studied the epithelium progressing over the zones from cortex toward papilla. Scanning electron microscopy demonstrated a small number of surface cells of a different morphology that were characterized by apical microvilli. The number of these microvillous lining cells increased as the epithelium covering the outer (zone 2-3) and inner (zone 3-4) stripe regions of the outer medulla was viewed, until the inner medulla was entirely covered by this cell type. In a reciprocal manner, the cells with the asymmetric apical plaques decreased in numbers and in their morphologic specialization in each successive region. The epithelium surrounding the inner medulla (zone 6-7) was completely devoid of this transitional cell type. Judging from the morphologic characteristics of the epithelia, one could surmise that little exchange of urea, water, and salts would occur with the extrarenal connective tissue or the cortical parenchyma. Recycling of urea might become more important physiologically with the outer stripe parenchyma, and even more so with the increased surfaces of the inner stripe parenchyma that lined the secondary pyramid, as well as with the epithelium lining the medulla.

Animals↗
PubMed1986

Stereological analysis of peroxisomes and mitochondria in intestinal epithelium of patients with peroxisomal deficiency disorders: Zellweger's syndrome and neonatal-onset adrenoleukodystrophy.

Peroxisomes, participants in lipid metabolism, have been shown to be altered in liver in two metabolic diseases in which long-chain fatty acids accumulate in tissues: Zellweger's syndrome and neonatal adrenoleukodystrophy (ALD). The intestine also plays a role in lipid metabolism, and we have had the opportunity to compare peroxisomes in normal intestinal epithelium with those from patients with Zellweger's syndrome and neonatal ALD at the electron microscopic level by using the combined techniques of cytochemistry and stereological analysis. Peroxisomes were numerous in intestinal epithelium of the normal individuals. They were ellipsoidal in shape with average diameters of 0.37 by 0.56 micron and filled with coarsely granular, DAB+ content. Peroxisomes in the intestinal epithelium of the ALD patient were similar in appearance and number but smaller in size (0.28 by 0.44 micron). Peroxisomes of normal appearance were absent from the intestinal epithelium of patients with Zellweger's syndrome; DAB+ content, however, was observed in rare, membrane-bound structures of much smaller size (0.12 by 0.19 micron). In liver of patients with Zellweger's syndrome, peroxisomes are lacking; in neonatal ALD they are abnormal in appearance and greatly reduced in number. The presence of rare minute peroxisomes in the intestinal epithelium in Zellweger's syndrome and of small peroxisomes in this epithelium in neonatal ALD indicate that peroxisomes in the intestinal epithelium are affected in these diseases, but to a lesser extent than in the liver. In the ALD intestinal epithelium, DAB+ material was also seen in long, sinuous, tubular or cisternal elements intermingled and occasionally in continuity with peroxisomes. It is suggested that these represent the early stages of peroxisome formation, the peroxisomal reticulum as originally envisioned by Lazarow, while the rare structures seen in Zellweger's represent rudiments of such a reticulum. Lamellar inclusions and clear spaces occurred in the cytoplasm adjacent to these structures indicating either that material accumulated there had been extracted during fixation or that these regions are more susceptible to autolysis. Mitochondria are also involved in lipid metabolism and have been reported to be abnormal in Zellweger's tissue. No qualitative differences were observed in the mitochondria of the intestinal epithelia examined in this study. Although quantitation revealed a greater mean volume, number, and surface density of mitochondria in the intestinal epithelia of neonatal ALD, it was not a statistically significant difference in all cases.

Adrenoleukodystrophy↗
PubMed1986

Crypt production in normal and diseased human colonic epithelium.

New crypts are added continuously to the adult mouse intestinal epithelium by a process of crypt replication. Branching crypts found in the epithelium represent a stage in the process of crypt replication. In "normal" human colonic epithelium we found a small but definite percentage of branching crypts, 0.44 +/- 0.16, indicating that new crypts are being produced at a low rate in this epithelium. Significantly higher (P less than .001) percentages of branching crypts, 30.4 +/- 5.75, 15.1 +/- 1.08, and 13.2 +/- 1.05, were found in diseased colonic epithelium from patients with ulcerative colitis, Crohn's disease, and multiple polyposis, respectively. These results may be interpreted as suggesting that the rate of crypt production in human colonic epithelium is increased in a number of disease states. We concluded that, as in the mouse intestinal epithelium, the rate of the crypt replication process in human colonic epithelium is plastic and may respond to a variety of conditions.

Aged↗
PubMed1995

An immunochemical, ultrastructural, and developmental characterization of the horizontal basal cells of rat olfactory epithelium.

The olfactory epithelium, which retains a capacity for neurogenesis throughout life, contains two categories of basal cells, dark/horizontal and light/globose, neither of which is fully characterized with respect to their function during the processes of neurogenesis and epithelial reconstitution after injury. The aim of this study was to define the potential biological role(s) of dark/horizontal basal cells (D/HBCs) in the epithelium by performing immunochemical, electron microscopic, and developmental analyses of this cell population. The D/HBCs express several specific immunochemical characteristics, which include the rat homologues of human cytokeratins 5 and 14, which were identified on the basis of staining with subunit-specific monoclonal antibodies and two-dimensional immunoblot analysis of the immunoreactive proteins. Indeed, the D/HBCs are the only cells in the olfactory mucosa that express these specific cytokeratins. The D/HBCs also express an alpha-galactose or alpha-N-acetyl galactosamine moiety to which the I beta 4 isolectin from Bandeiraea simplicifolia binds. Moreover, the D/HBCs are heavily labeled by two different antibodies against the EGF receptor and by a monoclonal antibody that binds to phosphotyrosine. These characteristics are also common to the basal cells of respiratory epithelium. The electron microscopic analysis of the basal region of the olfactory epithelium and the light microscopic immunofluorescence observations demonstrate that the D/HBCs provide a bridge between the basal processes of some sustentacular cells and the basal lamina. The most striking ultrastructural feature of the D/HBCs is their enfolding of virtually all bundles of olfactory axons within tunnels formed where D/HBCs arch over the basal lamina. The intimacy of the arrangement between D/HBCs and olfactory axons suggests that signals may pass from axons to D/HBCs or vice-versa. With respect to the development of D/HBCs, cells that express cytokeratins 5 and 14 and the EGF receptor first appear near the boundary with respiratory epithelium late in development, but do not extend throughout the olfactory epithelium until the middle of the first postnatal week. Taken together, the present findings and previously published data suggest that D/HBCs help to maintain the structural integrity of the olfactory epithelium, participate in its recovery from injury, and may also function to signal the status of the neuronal population of the epithelium.

Animals↗
PubMed1993

Differential expression of the cellular retinaldehyde-binding protein in bovine ciliary epithelium.

Differential expression of the cellular retinaldehyde-binding protein (CRALBP), a likely component of the visual cycle, has been observed in the ocular ciliary epithelium, a bilayer of neurepithelial cells involved in the active transport of aqueous humor. Antibody probes raised to bovine ciliary epithelium were used to isolate a cDNA encoding CRALBP from a bovine ciliary epithelium cDNA expression library. Northern analysis of poly A+RNA isolated from three different regions of the neonate ciliary epithelium revealed a three-fold higher level of CRALBP expression in the most anterior portion of the pars plicata region relative to the posterior pars plana region. Western blot analysis using CRALBP-specific antibodies also demonstrated that the level of CRALBP expression was higher in the most anterior portion of the ciliary epithelium and gradually decreases toward the posterior region in both neonate and adult bovine eyes. Using indirect immunofluorescence and frozen-sectioned bovine ciliary epithelium, CRALBP was localized to the pigmented ciliary epithelial cell layer along the entire ciliary epithelium. In the nonpigmented ciliary epithelial cell layer, CRALBP was only detected in the pars plana region. Pigmented ciliary epithelial cells have also been cultured and CRALBP expression demonstrated for several continuous passages by Northern and Western analysis. These results raise questions regarding the physiological role of CRALBP in the ciliary epithelium and the involvement of the protein in the defining regional and functional boundaries with this tissue.

Animals↗
PubMed1988

Epithelium selectively controls hypersensitization of the response of smooth muscle to leukotriene D4 by endogenous prostanoid(s) in guinea-pig trachea.

The effect of epithelium removal on the sensitivity of smooth muscle to carbachol and leukotriene D4 (LTD4) was investigated in guinea-pig isolated tracheal preparations untreated and treated with a cyclooxygenase inhibitor, flurbiprofen (1 mumol/l). The pD2 value of carbachol was not changed by epithelium removal or by flurbiprofen-treatment, alone or in combination. On the other hand, the pD2 of LTD4 was higher in the tracheal strips without epithelium than in the intact preparations. In preparations devoid of epithelium, the pD2 value of LTD4 was decreased by treatment with flurbiprofen, suggesting that the sensitivity of the smooth muscle (namely, epithelium-free preparations) to LTD4 is enhanced by intramurally produced excitatory prostaglandin(s) [PG(s)]. However, in intact preparations with epithelium, no such sensitized response to LTD4 was observed. After flurbiprofen-treatment, in the continued presence of prostaglandin F2 alpha (PGF2 alpha, 200 nmol/l), the sensitivity to LTD4 was partially recovered in the epithelium-free preparations, but not in the intact ones. These results suggest that epithelium diminishes the sensitizing effect of intramural excitatory PG(s) on responsiveness of tracheal smooth muscle to LTD4, possible via a non-prostanoid substance(s).

Animals↗
PubMed1992

Comparative study of the olfactory epithelium of the three-spined stickleback (Gasterosteus aculeatus) and the nine-spined stickleback (Pungitius pungitius).

The olfactory epithelium of the three-spined stickleback (Gasterosteus aculeatus) and the nine-spined stickleback (Pungitius pungitius) has been studied with a conventional histochemical and a novel immunological staining technique. In both species, the sensory epithelium is arranged in folds separated by non-sensory epithelial tissue. In the nine-spined stickleback, intrinsic folds consisting of non-sensory cells are found in the apical part of the sensory epithelium where they divide the surface of the sensory epithelium into small islets. These non-sensory cells are non-ciliated, flattened and piled on top of each other; they contain numerous electron-translucent vesicles. The intrinsic folds are absent from the sensory epithelium of the three-spined stickleback. In both species, axons of receptor cells form a layer of fibers in the sensory epithelium immediately above the basal cells. In the three-spined stickleback, thick branches of the olfactory nerve are frequently found in this layer. These branches are only occasionally observed in the sensory epithelium of the nine-spined stickleback. Thus, the three-spined stickleback and the nine-spined stickleback show considerable differences in the organization of the sensory regions of the olfactory epithelium.

Animals↗
PubMed1993

Detection by scanning electron microscopy of a distinctive esophageal surface cell at the junction of squamous and Barrett's epithelium.

Metaplastic columnar epithelium replaces the normal squamous epithelium in Barrett's esophagus. We characterized the surface epithelial cells of the junction between squamous and Barrett's epithelium using scanning electron microscopy and light microscopy. In four biopsy specimens from the squamous-Barrett's junction in three patients, we found a distinctive cell type having features intermediate between those of squamous and columnar epithelium. Its distinguishing characteristic is the presence on its surface of two disparate structures not normally present on the same cell in the gastrointestinal tract: microvilli (a scanning electron microscopy feature of glandular epithelium) and intercellular ridges (a scanning electron microscopy feature of squamous mucosa). The surface characteristics of this newly recognized cell were strikingly similar to those of cells found in the transformation zone of the uterine cervix, an area in which squamous epithelium physiologically replaces columnar epithelium. We also examined 28 biopsies of the gastroesophageal junction area from 14 patients with and without a history of heartburn but with no evidence of Barrett's esophagus. None of these biopsies showed the distinctive cell. We hypothesize that this distinctive cell represents an intermediate step in either the development or the healing of Barrett's epithelium, during which surface characteristics of two different cell types, columnar and squamous, coexist on the same cell.

Aged↗
PubMed1987

Expression of HLA-DR antigens on colonic epithelium in ulcerative colitis.

Although the expression of HLA-DR antigens on colonic epithelium in ulcerative colitis has been observed by several groups, the results of the expression in remission have been conflicting and there has been virtually no study concerning the expression in non-inflamed area in active ulcerative colitis. We studied systematically HLA-DR expression on colonic epithelium in 37 patients with ulcerative colitis chronologically, namely in remission as well as in the active stage and inflamed and non-inflamed areas simultaneously in the active stage. HLA-DR antigens were detected by indirect peroxidase staining using anti-HLA-DR monoclonal antibody. We confirmed the previous observation that epithelium from control colon does not express HLA-DR antigens, while epithelium from ulcerative colitis expresses the antigens with high frequency (83.3 percent). In addition, we demonstrated that HLA-DR expression on colonic epithelium in active ulcerative colitis disappeared in remission. Our new finding was that there is no HLA-DR expression on colonic epithelium in non-inflamed mucosa in active ulcerative colitis. Namely HLA-DR antigens were expressed only on inflamed epithelium of ulcerative colitis. These results lead to the conclusion that the expression of HLA-DR antigens on colonic epithelium in ulcerative colitis is closely related to the inflammation of mucosa.

Colitis, Ulcerative↗
PubMed1992

Vitamin A deficiency and inflammation: the pivotal role of secretory cells in the development of atrophic, hyperplastic and metaplastic change in the tracheal epithelium in vivo.

We showed previously that the proliferation of hamster airway secretory cells decreases during vitamin A deficiency (VAD) but later increases when submucosal inflammation develops (Virchows Arch [B] 59:231-242, 1990). This observation has important biological implications since two morphological extremes (atrophy and quiescence versus hyperplasia and hyperproliferation) are reported in the literature for VAD tracheal epithelium in vivo. In the present study, histological slides of tracheal rings from 35-day-old control and VAD hamsters (Virchows Arch [B] 45:197-219, 1984) were reviewed again. Rings from VAD hamsters were selected based on the absence or presence of a florid submucosal inflammation. Quantitative analyses were made on the cartilaginous part of rings from the anterior third of the trachea. When inflammation was absent, a mucociliary pseudostratified epithelium was, for the most part, maintained. The mitotic rate (MR, 6 h colchicine blockade) of secretory cells was markedly reduced (29-fold) but that of basal cells was not changed significantly. Moreover, cell density was not changed by VAD but ciliated cells and secretory cells were decreased and basal cells were increased, proportionally. We call this "minimal morphological change." Thinning (atrophy) of the minimally changed epithelium was associated with focal cell sloughing. Small scattered foci of epidermoid metaplasia (multiple layers of highly keratinized cells which were extremely flat, so that the epithelium was thin and attenuated) were also seen. We call this "atrophic epidermoid metaplasia." When inflammation was present, hyperplastic changes (stratification and epidermoid metaplasia) predominated and cells were in mitosis at all epithelial levels (low, middle, superficial) except in the most superficial (terminally differentiated) squames. The tracheal epithelium was thickened and hypercellular. The cells were piled up at the stratified lesions, and epithelial height, cell density and epithelial MR were significantly increased compared with the non-inflamed VAD epithelium. The effects of VAD and inflammation on cell proliferation were analyzed further by studying 7 h bromodeoxyuridine (BrdU) labelling patterns of cells in VAD tracheal epithelium, with and without submucosal inflammation. In addition, inflammation was induced in "minimally changed epithelium" by mild mechanical injury. The BrdU labelling patterns confirmed that DNA synthesis by secretory cells is reduced markedly by VAD. However, this suppression is overidden by the influx of inflammatory cells (the nature of the stimulus is unknown). The results indicate that the morphological contrasts (atrophy and hyperplasia) seen in the trachea during VAD in vivo are related to extremes in proliferation rates of tracheal secretory cells, regulated by VAD alone (minimal replication) and by inflammation (maximal replication).

Animals↗
PubMed1997

[Effect of diabetes mellitus on anterior central lens epithelium in cataract patients].

UNLABELLED: The relationship between diabetic metabolic disorder and the impairment of lens epithelium in the development of age-related cataract cannot be completely defined yet. In this prospective study, morphological criteria and the phosphorus content of the anterior central lens epithelium in type-II diabetics and nondiabetics are compared. PATIENTS AND METHODS: Fifty-six of the overall 159 patients with age-related cataracts were suffering from type-II diabetes (group I) and 103 are nondiabetics (group II). In each case, a fragment of the anterior central lens epithelium was evaluated morphologically using a scanning electron microscope (S-2400) and examined by EDXA (X-ray spectrometer TN-5500), with regard to phosphorus content. The criteria considered were the degree of damage to the epithelium (score 1-3), the morphologically evaluated cell density and the "peak/background" relationship for phosphorus. RESULTS: The mean degree of damage to the epithelium was 1.48 +/- 0.53 in the type-II diabetic group (I) and 1.55 +/- 0.65 in the nondiabetic group (II), respectively. The median cell density of type-II diabetics (group I) was 4838 +/- 1033 cells/mm2 compared with 5454 +/- 1368 cells/mm2 of the nondiabetics (group II). The mean "peak/background" relationship for phosphorus was 0.46 +/- 0.20 in group I and 0.51 +/- 0.26 in group II, respectively. CONCLUSION: In the younger patients, the significant decrease in cell density and the increased degree of damage to the anterior central lens epithelium in the type-II diabetic group could be attributed to the cataractogenic influence of diabetic metabolic disorder on the lens epithelium. Another possible indication for that was the smaller phosphorus content in this group as evidence of the decrease in the biological activity of the cells (ATP-function). The primary cataractogenic importance of the lens epithelium in type-II diabetics could not be concluded.

Adult↗