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PubMed2002

Comparison of the level of mitochondrial DNA A3243G mutation in esophageal epithelium and myocardium from individuals of very advanced age.

The A3243G mutation, one of the changes of human mitochondrial DNA (mtDNA) that accumulates in cells during aging, is a useful marker for investigating the aging of cells. We measured the mutation level of the mtDNA A3243G mutation using DNAs from two different tissues (esophageal epithelium and myocardium) from advanced elderly individuals. The mean level of the A3243G mutation for the esophageal epithelium was 0.0063+/-0.0019, and that for the myocardium was 0.0098+/-0.0031. The mutation level in the myocardium was significantly higher than that in the esophageal epithelium, indicating that more mtDNA A3243G mutations accumulated in the myocardium than in the esophageal epithelium. Since the myocardium is static with respect to cell turnover, but in the esophageal epithelium renewal is very rapid, it is possible that the mtDNA A3243G mutation in the myocardium accumulates more rapidly than in the esophageal epithelium. This phenomenon may reflect the difference in the longevity of cells in each of these tissues and their different levels of oxidative stress.

Aged↗
PubMed1992

Fine structure of the dorsal lingual epithelium of the domestic, newborn kitten, Felis catus.

The tip and the body of the tongue of the domestic kitten, Felis catus, were examined by light and transmission electron microscopy. On the tip of the tongue, no filiform papillae were observed, but the connective tissue papillae of the lamina propria were recognized. On the lingual body, there were filiform papillae composed of an anterior, a posterior and interpapillar epithelium. Under the transmission electron microscope, the epithelium on the tip of the kitten tongue was found to be of the stratified squamous type. The epithelium contained no cells filled with keratin fibers. In the lingual body, the interpapillar epithelium contained very few keratohyalin granules, and no cells with keratin fibers. In the epithelium on the anterior side of the filiform papillae, numerous keratohyalin granules appeared in the intermediate layer. In the surface layer, a thin layer of typical keratinized cells was visible. In the epithelium on the posterior side of the filiform papillae, a thick layer of keratinized cells was located on the surface layer.

Animals↗
PubMed1996

Ultrastructural study of the dorsal lingual epithelium of the Asian snail-eating turtle, Malayemys subtrijuga.

The Asian snail-eating turtle, Malayemys subtrijuga, is classified phylogenetically as a member of the family Emydinae. Members of this family usually live in small rivers or ponds. However, this species is relatively well-adapted to terrestrial life. We describe here the light, scanning electron and transmission electron microscopic appearance of the dorsal lingual epithelium of the snail-eating turtle and we compare the results to those obtained from other freshwater turtles in an attempt to clarify the relationship between the histological and ultrastructural differences in the lingual epithelium and the living circumstances of the turtles. The tongue is triangular with a rounded apex when viewed dorsally but it appears flattened when viewed laterally. Under the scanning electron microscope, no lingual papillae were visible on the dorsal surface of the tongue. Instead, plicae were seen all over the dorsal surface. On the surface of the epithelium of the outermost side, dome-shaped bulges, each of which was coincident with an individual cell, were compactly distributed. At higher magnification, scanning electron microscopy revealed numerous microvilli and microridges on the surface of these cells, and the thickening of cell-margins was clearly seen. Light microscopy revealed that the mucosal epithelium of the tongue was of the non-keratinized, stratified squamous type. Under the transmission electron microscope, the cells of the basal and deep intermediate layers of the epithelium appeared irregularly elliptical in shape. The nucleus was large and also irregularly elliptical, lying in the central region of each epithelial cell. The cytoplasm of these cells contained mitochondria, free ribosomes, rough endoplasmic reticulum and bundles of tonofibrils. Cell membranes formed processes around individual cells. Desmosomes were intercalated between the processes of adjacent cells. In the shallow intermediate layer, the cells were also elliptical, and the elliptical nucleus was located in the central area of each cell. A large part of the cytoplasm was occupied by electron-dense, discoid granules. Filamentous structures filled the spaces between these granules. Small numbers of free ribosomes, mitochondria and rough endoplasmic reticulum were scattered in the cytoplasm. Cell membranes still formed processes around cells. Desmosomes were intercalated between the processes of adjacent cells. The cells of the surface layer were still elliptical, as were their nuclei. Most of the cytoplasm was filled with electron-dense, discoid granules. Fine filamentous structures were dispersed between these granules. Cell membranes formed processes around cells which were coincident with microvilli and microridges. Intercalated desmosomes were also seen. In some cells, many of the electron-dense, discoid granules were secreted into the oral cavity. In conclusion, the histology of the lingual epithelium of the snail-eating turtle is very similar to that of the freshwater turtle, reflecting similarities in the gross morphology of the tongues of these species, in spite of the differences in their life styles.

Animals↗
PubMed1996

Ultrastructural study on the epithelium of ligated fallopian tubes in women of reproductive age.

The epithelium of normal and ligated Fallopian tubes in nine women of reproductive age was studied by using scanning electron microscopy (SEM). The results were as follows: at a distance of 0.5 cm from the ligated scar, numerous cilia of the epithelium were twisted and adhered, the shape of the epithelial cells was irregular, and even many microvilli and cilia lost from the local epithelium. However, the microvilli and cilia of the epithelium were normal on the mucosa at 1.0 cm from the ligated scar. This may account for the continued infertility following re-anastomosis of the ligated Fallopian tubes, due to the ultrastructural changes of oviducts and inability to convey the ova. Thus, at the Fallopian tube re-anastomosis, it is recommended that the removal of the mucosa should be at least 0.5 cm away from the ligated scar so as to increase the success rate of the fertilization. On the epithelium of the hydrosalpinx, Fallopian tube stomata located among the secretory cells were found for the first time. These stomata are small openings of lymphatic capillaries with a diameter of 3.25 microns to 4.25 microns. They are likely to be connected between the lumen of the Fallopian tube and subserous lymphatic vessels, and also involved in the drainage of the hydrosalpinx. Most or all cilia were lost from the ciliated cell surface on the epithelium of the hydrosalpinx, whereas the microvilli were flourishing. Therefore, many ciliated cells turned into secretory cells. In addition, a new pathogenesis of the hydrosapinx is discussed.

Adult↗
PubMed1999

Expression of ICAM-1 on conjunctival epithelium and ECP in tears and serum from children with allergic conjunctivitis.

BACKGROUND: Conjunctival eosinophilia may be considered to be an indicator of conjunctival allergic disease. The absence of eosinophils on conjunctival scraping, however, cannot rule out the diagnosis of allergic conjunctivitis because eosinophil infiltration may be deeper in conjunctival tissue. Eosinophil cationic protein (ECP) is a toxic product secreted by activated eosinophil as a marker of eosinophil activation. Eosinophil cationic protein concentrations in body fluids correlate with the severity of some allergic diseases. ICAM-1 promotes adhesion of leukocytes to epithelium, endothelium, and upregulates inflammation. Expression of adhesion can be modified by many extracellular and intracellular variables such as proinflammatory cytokines, extracellular matrix proteins, and viral infection. OBJECTIVE: We investigated whether local eosinophils are only activated in conjunctival epithelium or circulating activated eosinophils are involved in peripheral blood during allergic reaction of the eye. We also demonstrated the possible expression of ICAM-1 on epithelial cells from conjunctival scraping and compared them with soluble ICAM-1 values of serum and tears in children with allergic conjunctivitis and healthy children. METHODS: Seventeen subjects were selected on the basis of clinical manifestations, history, skin prick test, and total serum IgE. A microcapillary tube was used to collect the tears from the inner canthus. Conjunctival epithelia were obtained by scraping the upper tarsal conjunctiva. The level of ECP was measured by the CAP system, soluble ICAM-1 was measured by ELISA, and ICAM-1 on conjunctival epithelial cells were expressed by the avidine-biotin peroxide complex procedure. RESULTS: Serum IgE and the eosinophil count were increased in 10 out of 17 patients, positive skin prick tests were positive in 11 patients (Dermatophagoides pternyssinus; 9, Dermatophagoides farinae: 8), and eosinophilia in conjunctival epithelium was in 11 patients (4 patients: >3/HPF, 7 patients: 1-3/HPF). The ECP levels in tears were significantly increased in the patient group (12.0+/-8.0 versus 3.9+/-3.8 microg/mL, P = .01), but not in serum (52.5+/-43.1 versus 28.3+/-25.9 microg/mL). There is significant correlation between the eosinophil count in peripheral blood and on conjunctival epithelium (P = .007, r = .62; n = 25). The ICAM-1 expression score on conjunctival epithelial cells was significantly different between the patient group and controls (patient group: 1.77+/-1.25 versus control: 0.13+/-0.35 ng/mL, P = .002). There was a significant correlation between ICAM-1 expression on conjunctival epithelial cells and the ECP levels of tears (P = .01, r = .58; n = 25). Soluble ICAM-1 levels in serum and tears showed no significant difference between the patient group and controls, and also, there was no correlation between sICAM-1 levels in the serum and tears. CONCLUSION: Eosinophil cationic protein in tears and ICAM-1 expression scores on conjunctival epithelium showed a significant difference between children with allergic conjunctivitis and the healthy controls, but circulating ECP and sICAM-1 in serum were not significantly different between the two groups. These results may suggest that ICAM-1 is locally upregulated in inflammation, mediating eosinophil activation and migration to conjunctival epithelium, but is not involved as inflammatory mediators in peripheral blood during allergic response in children with allergic conjunctivitis.

Adolescent↗
PubMed1989

Spiral prominence epithelium.

Recent studies have shown neuroendocrine-type cells in human spiral prominence epithelium. A light microscopic and ultrastructural study was made on the guinea pig spiral prominence epithelium to try and identify neuroendocrine cells. The study showed that such cells were not present in the guinea pig spiral prominence epithelium. The spiral prominence epithelium was characterized by uniformity of cellular staining with Toluidine blue and the ultrastructural appearance. The morphology of the spiral prominence epithelium was similar to that previously described. The absence of neuroendocrine cells in spiral prominence epithelium in the guinea pig is discussed in relation to species differences.

Animals↗
PubMed2000

The distribution of carbonic anhydrase II in human, pig and rat oesophageal epithelium.

Carbonic anhydrase II (CA II) is present in human oesophageal epithelial cells and probably involved in protecting the mucosa against acidic gastric refluxate. If this is the case, then it is likely that the enzyme will be more concentrated at or near the gastro-oesophageal junction. To answer this question, and determine whether CA II is present and similarly distributed in other species, we also examined the oesophageal epithelium of the rat and pig. In the rat, CA II was largely absent from the oesophageal epithelium, but present in the stratified squamous epithelium of the gastric forestomach as an approximately 2 mm-long collar around the entrance to the corpus, a site that roughly corresponds to the gastro-oesophageal junction in other animals. The enzyme was present mainly in basal and prickle cells. In upper and middle pig oesophagus, CA II was largely confined to basal cells and isolated groups of stratified superficial prickle cells. CA II-containing epithelial cells were highly concentrated in the thickened epithelium at the gastro-oesophageal junction (about four-times thicker than upper or middle). Reactive cells were present throughout the depth of the epithelium, but noticeably more concentrated in the basal and superficial prickle cell layers. CA II was also prominent in the most superficial cell layers in islands of the oesophageal mucosa within the gastric cardia. In man, CA II was confined largely to the basal half of the epithelium in the upper and middle regions of oesophagus. The distribution of CA II at the gastro-oesophageal junction took different forms. In general, there were more CA II-reactive cells at or closer to the lumen. The superficial prickle cell layers tended to exhibit more CA II than the deeper layers, with basal and epibasal cells containing little or no enzyme. In other regions of the same specimens, CA II-containing cells were present from the basal to the most luminal layers. If CA II in oesophageal epithelial cells in the region of the gastro-oesophageal junction (or in the case of the rat the forestomach/corpus junction) is important in the defence against refluxate, then it is in a vulnerable site, since bile salts are potent inhibitors of the enzyme. The action of bile salts on CA II may be an important factor in the initiation of oesophageal disease.

Animals↗
PubMed1997

Changes in the distribution of integrins and their basement membrane ligands during development of human thyroid follicular epithelium.

Interactions between cells and basement membrane components are crucial for the regulation of epithelial cell differentiation and polarization. We have studied by immunohistochemical methods the distribution of integrin adhesion proteins and some of their basement membrane ligands in foetal (16-19 weeks) and adult thyroid follicular epithelia. A diffuse immunoreactivity for only alpha 3, alpha v and beta 1 integrins was found in foetal follicular epithelium, whereas in adult follicular epithelium these integrins were expressed basally in a polarized manner. Additionally, beta 3 integrin was seen in a more basolaterally confined manner in adult follicular epithelium. Among basement membrane components, laminin alpha 1, beta 1, gamma 1 and beta 2 chains were found in epithelial basement membranes of the foetal thyroid gland, suggestive of the presence of laminins-1 and -3. In contrast, the basement membranes of adult follicular epithelium presented a much weaker immunoreactivity for the laminin beta 2 chain. Furthermore, immunoreactivity for the laminin alpha 2 chain was occasionally seen in adult thyroid glands, apparently confined to myofibroblasts. Immunoreactivity for type IV collagen alpha 1 and alpha 2 (IV) chains was found in follicular basement membranes of foetal as well as adult thyroid gland. The results suggest that during maturation of foetal thyroid follicular epithelium a distinct polarization of integrins takes place. In mature thyroid follicular epithelium, the presumable adhesion-mediating integrin complexes are alpha 3 beta 1, alpha v beta 1 and/or alpha v beta 3 mediating adhesion to laminin-1 (alpha 1-beta 1-gamma 1) and type IV collagen trimer alpha 1(2) alpha 2 (IV).

Adult↗
PubMed2001

Immunohistochemical analysis of cell-cycle- and apoptosis-related factors in lining epithelium of odontogenic keratocysts.

We examined the immunohistochemical expressions of cell-cycle- and apoptosis-related factors to investigate the possible role of these factors in odontogenic keratocyst (OKC). Expression of cyclin D1 and p16 protein was detected in the basal and parabasal cells in lining epithelium of OKCs and was found more frequently in basal cell nevus syndrome (BCNS)-associated OKCs than in primary or recurrent OKCs. Positivity for p21 protein was detected in basal to superficial cells, whereas that for p27 protein was detected in parabasal to superficial cells in lining epithelium of OKCs. DNA topoisomerase IIalpha reacted with nuclei in basal and parabasal cells of the lining epithelium of OKCs, and positive cells were observed in BCNS-associated OKCs significantly more frequently than in primary or recurrent OKCs. Expression of Fas in suprabasal to superficial cells and expression of Fas-L in basal and parabasal cells were detected in lining epithelium of OKCs. Immunoreactivity for caspase-3 was detected in basal to suprabasal or superficial cells in lining epithelium of OKCs. Single stranded (ss)DNA-positive nuclei were detected in superficial cells in lining epithelium of OKCs. Fas was more broadly distributed in BCNS-associated OKCs than in primary OKCs, and ssDNA-positive cells were observed in BCNS-associated OKCs significantly more frequently than in primary or recurrent OKCs. These results suggest that BCNS-associated OKCs might be a distinguishable entity from solitary OKCs.

Adult↗
PubMed2001

The polarity of the retinal pigment epithelium.

The diversity of epithelia in the body permits a multitude of organ-specific functions. One of the foremost examples of this is the retinal pigment epithelium. Located between the photoreceptors of the retina and their principal blood supply, the choriocapillaris, the retinal pigment epithelium is critical for the survival and function of retinal photoreceptors. To serve this purpose, the retinal pigment epithelium cell has adapted the classic Golgi-to-cell-surface targeting pathways first described in such prototypic epithelial cell models as the Madin-Darby canine kidney cell, to arrive at a unique distribution of membrane and secreted proteins. More recent data suggest that the retinal pigment epithelium also takes advantage of its inherent asymmetry to augment the classical pathways of Golgi-to-cell-surface traffic. As retinal pigment epithelium transplants and gene therapy represent potential cures for retinal degenerative diseases, understanding the basis of the unique polarity properties of retinal pigment epithelium cells will be a critical issue for the development of future therapies.

Animals↗
PubMed1982

Altered glomerular permeability as a result of focal detachment of the visceral epithelium.

Changes in the permeability of the glomerular capillary wall (GCW) to native ferritin (NF), following detachment of the visceral epithelium from the glomerular basement membrane (GBM) were investigated. Detachment was induced by either perfusing kidneys with highly purified neuraminidase or by the induction of nephrosis through administration of puromycin aminonucleoside (PAN). Both experimental treatments resulted in marked glomerular ultrastructural changes which were characterized by focal detachment of the visceral epithelium from the GBM, replacement of the normal pattern of interdigitating foot processes with flattened expanses of continuous epithelium at certain areas of the GCW, and a generalized loss of sialic acid-rich epithelial cell cost in areas where the epithelium was detached as well as where it remained adherent. These changes were more frequent and prominent in the paramesangial regions of the glomeruli. When experimentally treated kidneys were perfused with NF, the tracer leaked into the urinary spaces in those areas of the GBM where the epithelium was detached. By contrast, in those areas of the GCW where the epithelium remained adherent, the tracer localized within the GBM mainly at the level of the lamina rara interna (LRI), and none of it appeared in the urinary spaces. Nephrotic and neuraminidase control kidneys were ultrastructurally normal, NF localizing mainly in the inner layers of the GBM. These data are consistent with the idea that the firm attachment of the epithelial foot processes to the GBM plays a vital role in determining the permselectivity properties of the GCW to plasma macromolecules.

Animals↗
PubMed1993

Histochemical markers reveal an unexpected heterogeneous composition of the renal embryonic collecting duct epithelium.

The ampullary collecting duct epithelium acts as an inductor in the embryonic and neonatal kidney. It induces the formation of all nephron generations and thus determines the whole architecture of the kidney. As the organ matures, the collecting duct epithelium itself transdifferentiates. The ampullary inductor epithelium, which appears homogeneous as revealed by light microscopy, develops into the well-known heterogeneous epithelium of the mature collecting duct consisting of light principal and dark intercalated cells. Up to now the mechanisms initiating and regulating this transdifferentiation step are unknown. Only very few data are available concerning functional characteristics of the ampullary epithelial cells of neonatal rabbit kidney. Therefore, a characterization of the collecting duct ampullary cells was carried out by means of immunohistological techniques using a set of different monoclonal antibodies and the lectin peanut agglutinin. All epithelial cells within the ampullary tip and neck were positive for cytokeratin 19, an intermediate filament protein. On the other hand, the monoclonal antibody CD 7 revealed a clear cut boundary between the ampullary neck and the ampullary tip region. Furthermore, after incubation with the monoclonal antibody BO-7 specifically reacting with intercalated cells of the mature collecting duct, both labeled and unlabeled cells were observed within the whole ampullary epithelium. These results were confirmed by scanning electron microscopical investigations which revealed two distinct epithelial cell populations. Thus, an unexpected heterogeneity of the ampullary epithelium could be demonstrated.

Amino Acid Sequence↗
PubMed1999

Modulation of ET-1-induced contraction of human bronchi by airway epithelium-dependent nitric oxide release via ET(A) receptor activation.

1. The purpose of this work was to investigate whether endothelin-1 (ET-1) was able to induce the release of an inhibitory factor from the airway epithelium in isolated human bronchi and to identify this mediator as well as the endothelin receptor involved in this phenomenon. 2. In intact bronchi, ET-1 induced a concentration-dependent contraction (-logEC50 = 7.92+/-0.09, n = 18) which was potentiated by epithelium removal (-logEC50 = 8.65+/-0.11, n = 17). BQ-123 , an ET(A) receptor antagonist, induced a significant leftward shift of the ET-1 concentration-response curve (CRC). This leftward shift was abolished after epithelium removal. 3. L-NAME (3 x 10(-3) M), an inhibitor of nitric oxide (NO) synthase, induced a significant leftward shift of the ET-1 CRC, and abolished the potentiation by BQ-123 (10(-8) M) of ET-1-induced contraction. 4. In intact preparations, the ET(B) receptor antagonist BQ-788 induced only at 10(-5) M a slight rightward shift of the ET-1 CRC. In contrast, in epithelium-denuded bronchi or in intact preparations in the presence of L-NAME, BQ-788 displayed a non-competitive antagonism toward ET-1-induced contraction. 5. IRL 1620, a selective ET(B) receptor agonist, induced a contraction of the isolated bronchus (-logEC50=7.94+/-0.11, n= 19). This effect was not modified by epithelium removal or by BQ-123. BQ-788 exerted a competitive antagonism against IRL 1620 which was similar in the presence or absence of epithelium. 6. These results show that ET-1 exerts two opposite effects on the human airway smooth muscle. One is contractile via ETB-receptor activation, the other is inhibitory and responsible of NO release which counteracts via ETA-receptor activation the contraction.

Antihypertensive Agents↗
PubMed2004

Optisol vs Dexsol as storage media for preservation of human corneal epithelium.

PURPOSE: To compare the efficacy of two storage media, Optisol GS and Dexsol, in preservation of donor corneal epithelium. METHODS: A total of 12 pairs of corneas not suitable for transplantation, all with intact epithelium, were used in this study, with one cornea of the pair stored in Optisol GS and its other counterpart in Dexsol. At each of three durations of storage--1, 2, and 4 days--four of these paired corneas were prepared for light microscopy and scanning and transmission electron microscopy. Another four pairs of control cornea were prepared in the same way and placed in universal fixative. MAIN OUTCOME MEASURES: Evaluation of the corneas was made by two observers masked as to the identity of the storage medium and length of storage. Loss of epithelial cells was evaluated by light microscopy. The attachment of the epithelium to the basement membrane,cellular integrity, intercellular junctions, and intracellular organelles were evaluated and compared by electron microscopy. RESULTS: The magnitude of epithelial loss correlated with the length of storage time. Control corneas maintained normal epithelium with preservation of all epithelial cell layers. Corneas stored for 1 day had minimal damage of the epithelium. Corneas stored for 2 days had a slight increase in epithelial damage, and corneas stored for up to 4 days showed a marked increase in epithelial damage. There were no significant differences between the two storage media. The basal cell layer was maintained in both the media at all time points, usually in good condition with mild-to-moderate damage in some cases. CONCLUSIONS: Loss of donor epithelium is related mainly to the length of storage and is similar in both Optisol GS and Dexsol. The storage time should be less than 4 days,especially when performing penetrating keratoplasty on patients with ocular surface disorders.

Aged↗
PubMed2005

Expression and subcellular localization of the AQP8 and AQP1 water channels in the mouse gall-bladder epithelium.

BACKGROUND INFORMATION: Transepithelial transport of water is one of the most distinctive functions by which the gall-bladder rearranges its bile content. Water is reabsorbed from the gall-bladder lumen during fasting, whereas it is secreted into the lumen following meal ingestion. Nevertheless, the molecular mechanism by which water is transported across the gall-bladder epithelium remains mostly unclear. RESULTS: In the present study, we investigate the presence and subcellular localization of AQP (aquaporin) water channels in the mouse gall-bladder epithelium. Considerable AQP8 mRNA was detected in the gall-bladder epithelium of mouse, calf, rabbit, guinea pig and man. Studies of subcellular localization were then addressed to the mouse gall-bladder where the transcript of a second AQP, AQP1, was also detected. Immunoblotting experiments confirmed the presence of AQP8 and AQP1 at a protein level. Immunohistochemistry showed intense expression of AQP8 and AQP1 in the gall-bladder epithelial cells where AQP8 was localized in the apical membrane, whereas AQP1 was seen both in the apical and basolateral membranes, and in vesicles located in the subapical cytoplasm. CONCLUSIONS: The pattern of subcellular distribution of AQP8 and AQP1 strongly corroborates the hypothesis of a transcellular route for the movement of water across the gall-bladder epithelium. Osmotic water would cross the apical membrane through AQP8 and AQP1, although AQP1 would be the facilitated pathway for the movement of water across the basolateral membrane. The presence of two distinct AQPs in the apical membrane is an unusual finding and may relate to the membrane's ability both to absorb and secrete fluid. It is tempting to hypothesize that AQP1 is hormonally translocated to the gall-bladder apical membrane to secrete water as in the bile duct epithelium, a functional homologue of the gall-bladder epithelium, whereas apical AQP8 may account for the absorption of water from gall-bladder bile.

Amino Acid Sequence↗
PubMed1977

Specific protein synthesis in isolated epithelium of guinea-pig seminal vesicle. Effects of castration and androgen replacement.

Four intrinsic soluble secretory proteins are synthesized in vitro by isolated seminal-vesicle mucosa from sexually mature guinea pigs. Newly synthesized specific proteins labelled with [(14)C]glycine and [(14)C]lysine were precipitated by using double-antibody immunoprecipitation techniques and their radioactivity was assessed. Rates of synthesis were determined on each of 5 days after castration. By 5 days after castration the wet weight of the epithelium decreased to 42% of intact control values; the absolute amount of specific protein synthesized in vitro after 60min incubation decreased to 28% and the 27500g cytoplasmic protein content decreased to 31%. Thus androgen deprivation leads to a decrease in general protein synthesis in vivo, as well as to a decrease in specific protein synthesis in vitro. Specific protein synthesis comprised 76% of the total protein formed in isolated tissue from animals 5 days after castration as compared with 99-100% in tissue from intact animals. At 72h after an injection of testosterone or dihydrotestosterone, seminal-vesicle epithelium wet weight, cytoplasmic protein content and capability for synthesizing specific proteins in vitro were restored to approx. 70% of normal values. At 72h after onset of therapy with 3alpha-androstanediol, both epithelium wet weight and cytoplasmic protein content had increased significantly, but without a corresponding increase in the capability of the isolated tissue to synthesize specific proteins. The soluble labelled proteins synthesized in vitro by isolated epithelium from intact animals during 60 or 120min incubation were essentially entirely immunoprecipitable, i.e. specific. In contrast, approx. 29% of all soluble protein newly synthesized by isolated epithelium from animals 5 days after castration was acid-precipitable, but not immunoprecipitable, i.e. ;non-specific'. The injection of testosterone into castrated animals inhibited the synthesis of the non-specific fraction by isolated tissue. The effects of castration on the ultrastructure of guinea-pig seminal-vesicle epithelium are also presented.

Androgens↗
PubMed1996

Conjunctival epithelial cells can resurface denuded cornea, but do not transdifferentiate to express cornea-specific keratin 12 following removal of limbal epithelium in mouse.

Limbal stem cell deficiency contributes to recurrent corneal epithelial defects. We examined whether the conjunctival epithelium can transdifferentiate to corneal epithelium following surgically induced limbal stem cell deficiency. Mice were anesthetized by intraperitoneal injection of sodium pentobarbital. Partial or total epithelial removal was produced with a no. 69 Beaver blade under a dissecting microscope. The wounds were allowed to heal for 0-28 days, and the mice were examined every other day to evaluate re-epithelialization. Corneas were then subjected to histological, immunohistochemical studies and Western blot analysis with epitope-specific anti-keratin 12 antibodies. Partial epithelial defects re-epithelialized within 2 days and were normal in appearance and expressed cornea-specific keratin 12. In eyes with limbal deficiency, re-epithelialization progressed more slowly and was characterized by opacification; epithelial closure usually occurred by the 7th day. This epithelium differed from normal corneal epithelium in basic morphology, cell shape, and the presence of goblet cells at 2 weeks after injury. The epithelium at the center of injured corneas with total defect at 4 weeks had cornealike morphology and was devoid of goblet cells. These epithelial cells derived from conjunctiva did not express the cornea-specific keratin 12 as determined by immunohistochemistry, Western blot analysis and in situ hybridization. As evidenced by differences in morphology and the expression of cornea-specific keratin 12, conjunctival transdifferentiation does not occur in conjunctical overgrowth after the removal of limbal epithelium.

Amino Acid Sequence↗
PubMed1998

Interactions between adult human prostatic epithelium and rat urogenital sinus mesenchyme in a tissue recombination model.

Tissue recombinants composed of adult human prostatic epithelium (hPrE) and rat urogenital sinus mesenchyme (rUGM) were grafted beneath the renal capsule of athymic rodent hosts. The pseudostratified human epithelium initially became multilayered, solid epithelial cords emerged, grew into the surrounding mesenchyme and canalized to regenerate a pseudostratified epithelium. Basal cells expressed cytokeratins 5 and 14, while luminal cells expressed cytokeratins 8 and 18, prostate specific antigen and prostatic acid phosphatase. The rat mesenchymal component differentiated into thick sheets of smooth muscle, characteristic of the human but not the rat prostate. These findings indicate that epithelial-mesenchymal interactions were reciprocal. Rat UGM induced adult hPrE to form new ductal-acinar tissue, involving epithelial proliferation, ductal branching morphogenesis and functional cytodifferentiation. Concurrently the epithelium dictated smooth muscle differentiation and patterning. Species-specific reverse transcriptase polymerase chain reaction SC (RT-PCR) analysis of the tissue recombinants was performed to separately examine the expression of epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), epidermal growth factor receptor (EGFR), TGF-beta 1, and TGF-beta 3 in the epithelium, stroma and host components of the graft. All of these genes, except TGF-beta 1, were expressed in all three tissues. Human TGF-beta 1 was not detected, indicating that this gene was not expressed in human prostatic epithelium but was present in stroma.

Adult↗