Layer Of Squamous Cells Research Articles

Autoradiographic study on the regenerative capability of the epithelium lining the center of the cornea after multiple debridements of its peripheral region

The epithelium lining the center of the cornea is assumed to lack stem cells.The purpose is to investigate by autoradiography the regenerative capability of the epithelium lining the central region of the rabbit cornea following seven scrapings of its peripheral lining, during several months. After marking the center of the cornea with a 6 mm-diameter trephine, the epithelium outside this area was scraped until reaching the corneoscleral zone. This procedure was repeated seven times on the same eye at intervals of 20 days. One day after the last scraping, (3)H-thymidine was injected intravitreally and the corneas processed for autoradiography. At 2 days after injection, the corneal surface was entirely lined by an epithelium made up by two layers of squamous cells, most of them being labeled with the DNA precursor. A multilayered epithelium was visualized at the center with most of its basal cells also labeled. The limbal epithelium had at least two of its layers labeled with the precursor. At 9 days, the multilayered central unscraped epithelium exhibited labeled cells not only in the basal but also in its suprabasal layers. The labeling index (labeled nuclei/100 cells) for its basal stratum was very close to 100%. A similar feature was observed at 16 days, except that the mutilayered central epithelium was seen lining a larger area when compared to the precedent interval and that it exhibited evidences for vertical renewal. The epithelium lining the central region of the cornea--where it was assumed that stem cells do not exist--exhibited capability for regeneration and self-renewal in spite of seven consecutive debridements of its periphery. No evidence was found for transposition of limbal epithelial cells to the center of the cornea during the early merger of the epithelial sliding fronts.

Experimental lamellar keratoplasty in rabbits using microfibrilar cellulose membrane: clinical, morphological and immunohistochemical findings

The clinical, histopathological and immunohistochemical features of the cornea were investigated in adult male New Zealand rabbits submitted to lamellar keratoplasty with microfibrillar cellulose membrane. Thirty animals were divided into five groups (n=6) and evaluated up to 60 days after surgery. Clinical examination revealed moderate manifestations of edema, blepharospasm and photophobia on the second day, which became mild or disappeared after the seventh day. This period was characterized clinically by repair of the corneal defect. Histopathological analysis showed the presence of a thin layer of squamous cells covering the damaged area as early as 7th day, accompanied by a mild infiltrate of polymorphonuclear cells. Blood vessels were observed in the epithelium after the 15th day, which had regressed by day 48. Ki67 antibody labeling showed an increase of proliferating cells in the epithelium by the 15th day and in the stroma by day 30. Remodeling and epithelial adhesion were observed during this period. Microfibrillar cellulose membrane (Bionext®) used for lamellar keratoplasty was found to yield good results considering the good integration of the implant.

Anatomy of the human corneal innervation

The anatomy of the human corneal innervation has been the subject of much investigation; however, a comprehensive description remains elusive. The purpose of the present study was to provide a detailed description of the human corneal innervation using a novel approach involving immunohistochemically stained anterior-cornea whole mounts. Sixteen donor corneas aged 19–78 years were cut with a 6.0 mm trephine into a central plug and two peripheral rims. Each specimen was sectioned serially on a cryostat to produce several 100 μm-thick stromal sections and a 100–140 μm-thick anterior-cornea whole mount that contained the entire corneal epithelium and much of the anterior stroma. The corneal innervation was stained with a primary antibody against beta neurotubulin and subjected to rigorous quantitative and qualitative analyses. The results showed that a mean of 71.3 ± 14.3, uniformly spaced, main stromal nerve bundles entered the cornea at the corneoscleral limbus. The bundles averaged 20.3 ± 7.0 μm in diameter, were separated by a mean spacing of 0.49 ± 0.40 mm, and entered the cornea at a mean distance of 293 ± 106 μm from the ocular surface. Each stromal bundle gave rise through repetitive branching to a moderately dense midstromal plexus and a dense subepithelial plexus (SEP). The SEP was comprised of modest numbers of straight and curvilinear nerves, most of which penetrated Bowman's membrane to supply the corneal epithelium, and a more abundant and anatomically complex population of tortuous, highly anastomotic nerves that remained largely confined in their distribution to the SEP. SEP density and anatomical complexity varied considerably among corneas and was less dense and patchier in the central cornea. A mean of 204 ± 58.5 stromal nerves penetrated Bowman's membrane to supply the central 10 mm of corneal epithelium (2.60 nerves/mm 2). The density of Bowman's membrane penetrations was greater peripherally than centrally. After entering the epithelium, stromal nerves branched into groups of up to twenty subbasal nerve fibers known as epithelial leashes. Leashes in the central and intermediate cornea anastomosed extensively to form a dense, continuous subbasal nerve plexus, while leashes in the peripheral cornea demonstrated fewer anastomoses and were less complex anatomically. Viewed in its entirety, the subbasal nerve plexus formed a gentle, whorl-like assemblage of long curvilinear subbasal fibers, 1.0–8.0 mm in length, that converged on an imaginary seam or gentle spiral (vortex) approximately 2.51 ± 0.23 mm inferonasal to the corneal apex. Mean subbasal nerve fiber density near the corneal apex was 45.94 ± 5.20 mm/mm 2 and mean subbasal and interconnecting nerve fiber diameters in the same region were 1.51 ± 0.74 μm and 0.69 ± 0.26 μm, respectively. Intraepithelial terminals originated exclusively as branches of subbasal nerves and terminated in all epithelial layers. Nerve terminals in the wing and squamous cell layers were morphologically diverse and ranged in total length from 9 to 780 μm. The suprabasal layers of the central corneal epithelium contained approximately 605.8 terminals/mm 2. The results of this study provide a detailed, comprehensive description of human corneal nerve architecture and density that extends and refines existing accounts. An accurate, detailed model of the normal human corneal innervation may predict or help to understand the consequences of corneal nerve damage during refractive, cataract and other ocular surgeries.

Age-Related Morphologic and Microscopic Variations in Syrian Hamster Ovaries and Oocytes.

Factors contributing to age-related decline in fertility rate include quantity and quality of follicles and their associated oocytes and their responsiveness to reproductive hormones. Mitochondria and smooth endoplasmic reticulum are purportedly components of oocyte cytoplasmic senility. We have evaluated ovarian follicle number and egg production and the microscopic variations in mitochondria and smooth endoplasmic reticulum (SER) between young (2-4 mos.) and old (12-18 mos.) Syrian hamster oocytes. Experimental animals were superovulated by intraperitoneal injections of pregnant mare serum gonadotropin followed at 54 hrs by human chorionic gonadotropin 8-14 hrs prior to the collection of ovaries and oocytes. At eight hrs, ovaries were collected for primordial/primary follicle counts. At 14 hrs oocyte masses were collected for microscopic analysis. Hematoxylin and eosin staining of ovarian tissue from two animals evaluated through serial sections established a 67% decrease in primordial/primary oocytes in old versus young hamster ovaries. Primordial/primary follicles contained a germinal vesicle and either a single layer of squamous epithelial cells or one to three layers of cuboidal epithelial (granulosa) cells without follicular antra. A 30% reduction in oocyte number was collected from superovulated old (avg. 20.9, n=45) versus young (avg. 29.8, n=42) hamsters. Comparing the ultra structural components of oocytes superovulated from young and old hamsters showed young hamsters having more mitochondria and smooth endoplasmic reticulum (SER) than old hamsters as seen in other species. All oocyte mitochondria had large amounts of electron dense areas, also seen in other species, but old ova had reduced number of distinct cristae and an increased electron dense mitochondrial area. Young ova had no collapsed SER while old ova were replete with areas of collapsed, non-luminal SER. The non-luminal stretches of SER were adjoined to and contiguous with the normal-looking SER strands in the old oocytes. Evaluating ova from 3 young and 4 old females under 32x magnification, 89% of young ova were predominantly expanded against the zona pellucida (no perivitelline space) with a clear indentation at the polar body while 48% of old ova could be described in this way. The remaining old ova had increased perivitelline space with no indentation from the polar body. In conclusion the results not only support the theory of oocytes depletion as aging occurs, but also suggest morphological changes of mitochondria and SER in oocytes may be attributing factors in the age-related decline in fertility rate. This research was supported by The Jones Institute Foundation and the Department of Obstetrics and Gynecology of the Eastern Virginia Medical School. (poster)

Pseudoglandular (Adenoid, Acantholytic) Penile Squamous Cell Carcinoma

Almost half of penile squamous cell carcinomas (SCCs) are of the usual type but there is a variegated spectrum of morphologically distinctive subtypes. In a pathologic review of 375 uniformly diagnosed and treated patients with penile SCC, we found 7 tumors with predominant pseudoglandular or adenoid features. The aim of the study was to delineate clinicopathologic features and outcome of an unusual variant of penile SCC. Clinical charts and pathologic materials were reviewed. The following informations were obtained: patient's age, tumor site, size, histologic grade (1, 2, and 3), thickness in millimeters, anatomic level of invasion [corpus spongiosum, corpus cavernosum (CC)], vascular and perineural invasion, groin nodal status, and follow-up in months. These features were compared with those of 224 cases of usual SCCs. Median age of the patients was 54 years. Tumors were large (average 4.6 cm) and involved multiple sites in 4 cases; exclusively the glans in 2 and site was unknown in 1. Microscopically, tumors were SCC with acantholytic areas ranging from solid nests with early necrosis or empty pseudoluminal spaces lined by 1 layer of squamous cells or cylindrical cells strikingly simulating glands. Tumors were deeply infiltrating (4 invaded CC, 2 corpus spongiosum, and 1 invaded preputial dermis) and were of high histologic grade (6 cases). Vascular invasion was present in 4 cases and perineural invasion in 2. The differential diagnosis was with gland forming penile tumors (surface adenosquamous, mucoepidermoid, and urethral adenocarcinomas) and the angiosarcomatoid variant of sarcomatoid carcinomas. There was regional nodal metastasis in 3 patients, 2 of which died from disease. The other 5 were either alive with no evidence of disease (12 and 21 y after diagnosis) or died from causes other than penile cancer (3, 4, and 7 y after diagnosis). Comparing with usual SCCs, pseudoglandular SCCs were of higher grade (88% vs. 44%), invaded deeper into CC (71% vs. 52%), and showed a higher incidence of regional metastasis (42% vs. 25%) and higher mortality (29% vs. 19%).

Gestational morphogenesis of the uterine epithelium of the gummy shark (Mustelus antarcticus)

Developing embryos of the non-placental, viviparous gummy shark (Mustelus antarcticus) are supplied with yolk from external and internal yolk sacs throughout the initial stages of gestation. Yolk supplies are exhausted by the 7th month of an 11-12 month gestation. During embryonic development, there is an approximate 800% gain in dry mass. These factors suggest nutrients are transferred from the mother to the young. The results of the present study provide some insights into how this is occurring. The uteri are paired and both are functional. Using both light and transmission electron microscopy, regions of the uterus were examined throughout maturation and gestation. The layers of the uterine wall throughout the entire length are similar to the uteri of other chondrichthyans previously examined. The uterine epithelium of the body of the uterus is smooth contoured, does not form villi, and undergoes cyclical and secretory changes throughout maturity and gestation. In immature uteri, the epithelium is simple columnar with minimal periodic acid-Schiff-positive and Alcian blue-positive secretory vesicles. In mature uteri, the epithelium is highly stratified with cuboidal cells containing numerous Alcian blue-positive and periodic acid-Schiff-positive vesicles. With pregnancy, prominent changes include a reduction in the number of cell layers, a reduction in cell size, a reduction in the connective tissue intervening between epithelium and blood vessel endothelium, and an increase in blood vessel number and size, so that at term, the uterine compartment consists of a single layer of squamous cells immediately underlain by sinusoidal-like blood vessels. These features along with a small number of secretory vesicles, dilated intercellular spaces, and clear transport vesicles suggest the transepithelial transfer of water and minerals from the maternal to embryonic environment, supplemented by minimal uterine secretions. This is defined as minimal histotrophy and this article represents the first detailed description of this reproductive mode.

Distribution and morphology of the ampullary organs of the estuarine long-tailed catfish, Euristhmus lepturus (Plotosidae, Siluriformes)

Ampullary organs of Euristhmus lepturus occur in high densities along the head and in four parallel pathways along the trunk of the body. Large ampullary pores (125–130 μm) are easily distinguishable from other sensory epithelial pores due to the differences in size and the presence of a collar-like structure. Simple, singular ampullary organs of the head region consist of an ampullary pore connected to a long canal with a diameter of 115–175 μm before terminating as a simple ampulla with an external diameter of 390–480 μm. The ampullary canal is composed of 1–2 layers of flattened squamous epithelial cells, the basement membrane and an interlocking collagen sheath. The innermost cells lining the canal wall are adjoined via tight junctions and numerous desmosomes, as are those of the receptor and supportive cells. Canal wall tissue gives rise to a sensory epithelium containing between 242 and 285 total receptor cells, with an average diameter of 11.7 ± 5.3 μm, intermixed with medially nucleated supportive cells. Each receptor cell (21.38 ± 4.41 μm, height) has an apically positioned nucleus and a luminal surface covered with numerous microvilli. Neural terminals abut the basal region of receptor cells opposite multiple presynaptic bodies and dense mitochondria. Supportive cells extend from the ampullary lumen to the basement membrane, which is adjacent to the complex system of collagen fibres.

Differential expression and localization of connexins 26 and 43 in the rat gingival epithelium

We investigated the expression and localization of connexins (CX) 26 and 43 in the rat gingival epithelium. RT-PCR analysis revealed CX26 gene expression in both the upper and lower layers of the gingival epithelium and in the total epithelial layer, whereas CX43 gene expression was limited to the lower layer and the total epithelial layer. Immunoreactivity for CX43 was observed in the membranes of adjacent cells from the basal layer to the middle of the prickle cell layer, while immunoreactivity for CX26 was observed in the granular cell layer and lower part of the squamous cell layer. Merged images revealed the co-localization of CX26 and CX43 in the middle of the prickle cell layer. By immuno-electron microscopy, gap junctions appeared curved, hemi-circular, or annular within the cytoplasm, and gold particles indicating the presence of CX43 were localized at the outer edges of these cytoplasmic formations. These results suggest that CX43 is associated with the regulation of cell proliferation and that increased CX26 expression is associated with differentiation of keratinocytes. Thus, degradation of CX43 is considered to play an essential role in differentiation of the rat gingival epithelium.

Ultrastructural changes in the follicular epithelium ofCeratophrys cranwelliprevitellogenic oocytes

In this work we carried out ultrastructural, autoradiographic and biochemical analyses of the follicular epithelium during C. cranwelli previtellogenesis. This study revealed that the follicular epithelium in early previtellogenesis is constituted of a single layer of squamous homogeneous cells. During mid-previtellogenesis two types of cells develop: dark cells and clear cells. The follicular dark cells are actively involved in the synthesis of RNA, which is transferred to the oocyte through the interface. In late previtellogenesis the dark cells show apoptotic characteristics such as chromatin condensation, DNA fragmentation and cytoplasm shrinkage. This process forms apoptotic bodies that seem to be engulfed by the oocyte. Our results show evidence that, during mid- and late C. cranwelli previtellogenesis, the follicular epithelium undergoes remodelling processes interacting with the oocyte.

Expression of apoptosis regulatory proteins p53 and Bcl‐2 in skin of patients with chronic renal failure on maintenance haemodialysis

Chronic renal failure results in multi-organ system derangement including cardiovascular, gastrointestinal, neurological, endocrinal, blood and dermatological abnormalities. Maintenance of skin homeostasis requires a delicate balance between proliferation, differentiation and apoptosis. p53 and Bcl-2 proteins play a central role in the regulation of apoptosis. Evaluation of the expression of apoptosis regulatory proteins p53 and Bcl-2 in apparently normal skin of patients, with chronic renal failure on maintenance haemodialysis, with respect to their role in the apoptotic process. Biopsy specimens were obtained from 10 patients with chronic renal failure on maintenance haemodialysis, as well as seven age-matched control subjects. Computer-assisted image analysis was employed to measure epidermal thickness in H&E-stained sections. Immunoperoxidase technique was also used to demonstrate p53 and Bcl-2 proteins and the TUNEL technique for detection of apoptotic cells in these specimens. The mean epidermal thickness was significantly higher (P < 0.0001) in patients than controls. Meanwhile, no apoptotic cells were detected in the epidermis of patients. On the other hand, a statistically significant difference was observed in both p53 (P = 0.0001) and Bcl-2 expression (P = 0.0003) when comparing patients and controls. Expression of p53 (2.74 +/- 0.84) and Bcl-2 (3.45 +/- 1.35) proteins was higher in skin samples obtained from patients with chronic renal failure and on maintenance haemodialysis than those from control cases (0.5 +/- 0.96 and 0.8 +/- 0.6, respectively). Moreover, Bcl-2 expression in patients was observed in basal as well as squamous cell layers of skin, whereas in control subjects it was confined to the basal cell layer only. These findings suggest that an alteration in the proliferation/apoptosis balance may be present in the skin of such patients.

Role of Neurotrophins and Neurotrophin Receptors in Rat Conjunctival Goblet Cell Secretion and Proliferation

To determine which neurotrophins (NTs)-nerve growth factor (NGF), brain-derived neurotrophin (BDNF), neurotrophin-3 (NT3), and neurotrophin-4 (NT4)-and their receptors (NTrs) TrkA, TrkB, TrkC, and p75 are present in rat conjunctiva and cultured rat goblet cells (CGCs) and whether NTs stimulate glycoconjugate secretion or cell proliferation. Western blot analysis and immunofluorescence microscopy determined presence and location of NTs and NTrs. CGCs were incubated with NTs (10(-12)-10(-8) M) for 2 or 24 hours to measure secretion or proliferation, respectively. An enzyme-linked lectin assay analyzed glycoconjugate secretion. WST-8 determined cell proliferation. Western blot analysis showed all NTs and NTrs in both conjunctiva and CGCs. The cytoplasm of conjunctival stratified squamous cells and goblet cell lateral membranes contained NGF, BDNF, and NT4. Stratified squamous cell membranes contained NT3. In CGCs, NGF and BDNF had punctuate perinuclear staining. The nucleus contained NT3 and cytosol contained NT4. TrkA, TrkB, and p75 immunoreactivity was on conjunctival goblet cell lateral membranes. Plasma membranes of the basal layer of stratified squamous cells contained TrkA. Stratified squamous cell and goblet cell nuclei contained TrkC. In CGCs, all NTrs were present in the nucleus. NGF and BDNF, but not NT3 and NT4, induced a concentration-dependent stimulation of secretion from CGCs with a maximum increase of 10(-9) M each. No effect on cell proliferation was detected with any NTs. Rat conjunctival goblet cells and CGCs contain all NTs and NTrs. Only NGF and BDNF stimulated goblet cell glycoconjugate secretion, and none induced CGC proliferation.

ADP-Ribosylation Factor-Like 3 Is Involved in Kidney and Photoreceptor Development

ADP-ribosylation factor-like 3 (Arl3) is a member of a small subfamily of G-proteins involved in membrane-associated vesicular and intracellular trafficking processes. Genetic studies in Leishmania have shown that the Arl3 homolog is essential for flagellum biogenesis. Mutations in a related human family member, Arl6, result in Bardet-Biedl syndrome in humans, which is characterized by genital, renal, and retinal abnormalities, obesity, and learning deficits. As part of our large-scale phenotypic screen, mice deficient for the Arl3 gene were generated and analyzed. Arl3 (-/-) mice were born at a sub-Mendelian ratio, were small and sickly, and had markedly swollen abdomens. These mutants failed to thrive, and all died by 3 weeks of age. The (-/-) mice exhibited abnormal development of renal, hepatic, and pancreatic epithelial tubule structures, which is characteristic of the renal-hepatic-pancreatic dysplasia found in autosomal recessive polycystic kidney disease. Absence of Arl3 was associated with abnormal epithelial cell proliferation and cyst formation. Moreover, mice lacking Arl3 exhibited photoreceptor degeneration as early as postnatal day 14. These results are the first to implicate Arl3 in a ciliary disease affecting the kidney, biliary tract, pancreas, and retina.

Branchial‐like cysts of the thyroid associated with solid cell nests

Presented herein is the case of a 65-year-old man with a 20 year history of thyroid hypofunction. On sonography a cystic lesion 4 x 4 x 5 cm in largest diameter was found, replacing most of the right lobe of the thyroid gland. Microscopically, the lesion was composed of labyrinth-like cystic structures (LCS) lined by a few layers of benign-appearing squamous cells and filled by mucinous material. Adjacent to the cyst walls were discontinuous patches of a lymphoid tissue, composed of haloed centrocyte-like cells or germinal centers mostly depleted of germinal cells. Additionally, there were numerous squamous cell nests equivalent to solid cell nests (SCN), all of which were surrounded by a similar-looking lymphoid tissue. Rare SCN were thus cystically changed and contained a small amount of mucus. The SCN communicated with the LCS: the former represented the most distal outpouchings of the latter. The epithelial structures were surrounded by a loose collagenous adipocytic stroma with plump fibroblasts, which resembled the stroma often seen in lateral neck cysts associated with structures such as cartilage, accessory salivary gland tissues, cysts and accessory thyroid and thymus. Immunohistochemically, all lesional elements were negative for calcitonin and thyroglobulin. The results of the paper suggest that branchial cleft-like cyst have an origin in the ultimobranchial body.

Signaling interactions between squamous and columnar epithelia of the Drosophila wing disc

Understanding the interactions between distinct epithelial cells would help us to understand the development of tissues. Drosophila imaginal discs, which are made up of two types of epithelial cells, provide good model systems for such studies. The disc proper or the columnar epithelial cells are apposed to a layer of squamous epithelial cells (the peripodial membrane). We have examined organization of peripodial and disc proper cells vis-à-vis their polarity since cell polarity plays an important role in the polarized transport of signaling molecules. With the help of polarity-specific cell markers, we have observed that apical surfaces of peripodial and disc proper cells face each other. This provides the cellular basis for the recently demonstrated signaling interactions between peripodial and disc proper cells during disc patterning. We also report significant similarities as well as differences between peripodial and disc proper cells in Engrailed-dependent wingdisc-patterning events, which make them an appropriate model system for studying the mechanism of diffusion of signal molecules, such as Hedgehog. Results with wild-type and two mutant forms of Hedgehog suggest that direct cell-cell contact is a requirement for the movement of wild-type Hedgehog signal and reconfirm that cholesterol-modification of Hedgehog makes it a short-range signaling molecule by restricting its movement.

Oogenesis in the viviparous matrotrophic lizard Mabuya brachypoda

Oogenesis in the lizard Mabuya brachypoda is seasonal, with oogenesis initiated during May-June and ovulation occurring during July-August. This species ovulates an egg that is microlecithal, having very small yolk stores. The preovulatory oocyte attains a maximum diameter of 0.9-1.3 mm. Two elongated germinal beds, formed by germinal epithelia containing oogonia, early oocytes, and somatic cells, are found on the dorsal surface of each ovary. Although microlecithal eggs are ovulated in this species, oogenesis is characterized by both previtellogenic and vitellogenic stages. During early previtellogenesis, the nucleus of the oocyte contains lampbrush chromosomes, whereas the ooplasm stains lightly with a perinuclear yolk nucleus. During late previtellogenesis the ooplasm displays basophilic staining with fine granular material composed of irregularly distributed bundles of thin fibers. A well-defined zona pellucida is also observed. The granulosa, initially composed of a single layer of squamous cells during early previtellogenesis, becomes multilayered and polymorphic. As with other squamate reptiles, the granulosa at this stage is formed by three cell types: small, intermediate, and large or pyriform cells. As vitellogenesis progresses the oocyte displays abundant vacuoles and small, but scarce, yolk platelets at the periphery of the oocyte. The zona pellucida attains its maximum thickness during late oogenesis, a period when the granulosa is again reduced to a single layer of squamous cells. The vitellogenic process observed in M. brachypoda corresponds with the earliest vitellogenic stages seen in other viviparous lizard species with larger oocytes. The various species of the genus Mabuya provided us with important models to understand a major transition in the evolution of viviparity, the development of a microlecithal egg.

In Vivo Pathological Diagnosis of Esophageal Lesions Using An Endo-Cytoscopy System

Background: Recently, some groups have tried to acquire a direct image of histology in vivo gastrointestinal mucosa (virtual histology). Aim: The aim of this study is to observe the endoscopic characteristics of in vivo cells on the surface layer of various esophageal lesions. Patients and Methods: We examined twenty cases of superficial [email protected] , dysplasia, and Barrett's esophageal cancer using an newly developed Endo-cytoscopy system with methylene blue staining. Equipment: An Endo-cytoscopy system (Olympus, prototype) consisting of two flexible endoscopes, 380 cm long and 3.2 mm in diameter, was employed. These endoscopes passed through the instrument channel of the GIF-1T240 (Olympus). The low-magnification type (XEC300) provided 450X magnification and a field of view of 300x300ƒÊm of tissue. The second endoscope was a higher-magnification type (XEC120) that provided 1125X magnification and a field of view of 120x120ƒÊm of tissue. Results: By observing the normal esophageal mucosa using an [email protected] and methylene blue staining, we were able to observe cells on the surface of the squamous epithelium. These cells were arranged homogeneously with a uniform and low nucleus-cytoplasmic ratio. In esophageal cancer, the density of cells was observed to be much higher than in the normal squamous epithelium. Further, the cell distribution was irregular and the cells were extremely heterogeneous with nuclei that differed in staining, size and shape. The nucleus-cytoplasm ratio was also very irregular. In mild dysplasia, surface cells were observed as normal squamous cells. Histological examination of this lesion showed that the atypical cells were limited to the half of the squamous cell layer close to the basement membrane. The superficial layer was covered by normal squamous cells. In the case of Barrett's esophageal cancer, we were able to observe the cells and nuclei of the Barrett's esophageal mucosa. These cells formed a crypt and the cell density was low. In the cancer lesion, the crypt formation was destroyed, and the cell density was high compared with the non-cancerous Barrett's mucosa. The cells had large and darkly stained nuclei compared with part of the Barrett's metaplasia. Conclusions: Observation using the Endo-cytoscopy system allowed us to examine in detail histological alterations in esophageal lesions.

Amniotic membrane as a carrier for cultivated human corneal endothelial cell transplantation.

It would be advantageous if cultivated human corneal endothelial cells (cHCECs) could be transplanted for the treatment of diseases caused by corneal endothelial disorders. To achieve this, a matrix that can serve as a carrier for cHCECs is needed. The present study was conducted to examine the feasibility of using amniotic membrane (AM) as a carrier for this application. HCECs obtained from peripheral corneal tissue were cultivated, passaged, and transplanted onto denuded AM. The cell density and morphology of the resultant cHCECs on AM were examined by light, scanning electron, and transmission electron microscopy. To determine whether these cHCEC sheets on AM carrier were functional in vivo, the cHCEC sheets on AM were transplanted onto rabbit corneas whose Descemet's membrane and endothelial cells had been completely removed. After transplantation, the corneal appearance was examined by slit lamp biomicroscopy, and corneal thickness was measured daily by pachymetry. At 7 days after surgery, the grafts were examined by light, scanning electron, and transmission electron microscopy. The density of the cHCECs on AM was greater than 3000 cells/mm(2). Morphologically, the cHCEC sheets consisted of a fairly continuous layer of flat squamous polygonal endothelial cells that appeared uniform in size with tightly opposed cell junctions in vitro and in vivo after transplantation. The corneas that received transplanted cHCEC sheets had little edema and retained their thinness and transparency. The cell density and morphology of cHCECs on AM were similar to those of normal corneas, and cHCECs on AM were functional in vivo. These results indicate that AM maintains HCEC morphology and function and could serve as a carrier for cHCEC transplantation.

Development of the digestive tract of gilthead sea bream (Sparus aurata L.). Light and electron microscopic studies

Light and electron microscopic studies of the digestive tract of gilthead sea bream were carried out from hatching to 69 days. Five significant phases were established. Phases I and II comprise the lecitotrophic period. During phase I, the yolk sac was large and the uniform digestive tract showed a layer of squamous epithelial cells with numerous free ribosomes. Phase II was characterized by the opening of the anus and the differentiation of three digestive regions: the esophagus, with a stratified epithelium, the presumptive stomach, whose cuboid epithelial cells had some apical processes and clear vesicles, and the intestine with large intercellular spaces among prismatic epithelial cells that had a PAS-positive striated border. Phase III, or lecitoexotrophic period, began with the opening of the mouth; absorption of the yolk sac started and the intestine became differentiated into two regions separated by a valve. Intestinal epithelial cells showed basal lamellar structures and lipoprotein particles. Some columnar cells appeared inside the epithelium of the esophagus. Phases IV and V comprise the exotrophic period; phase IV began with the disappearance of the yolk sac; mucous cells containing sulphomucin-type acid mucosubstances appeared in the esophagus and goblet cells, with acid and neutral mucosubstances appeared in the intestine. The epithelial cells of the first and posterior intestinal segments showed large lipid droplets and heavy pinocytosis with large supranuclear vesicles and numerous lysosomes, respectively. Phase V was marked by the appearance of neutral mucosubstances in the esophageal mucous cells and in the stomach epithelial cells, and the differentiation of pyloric caeca and gastric glands. The ultrastructural features of glandular cells indicated that they secrete both pepsinogen and hydrochloride acid. The epithelial cells of the first intestinal segment showed large lipid droplets, often close to mitochondria, at the beginning of this phase. These lipid droplets decreased in size, while the rough and smooth endoplasmic reticulum and Golgi complex, related to lipoprotein synthesis, progressively developed during this phase. Pinocytotic and large supranuclear vesicles disappeared from epithelial cells of the posterior intestinal segment.

Aberrant arachidonic acid metabolism in esophageal adenocarcinogenesis, and the effects of sulindac, nordihydroguaiaretic acid, and alpha-difluoromethylornithine on tumorigenesis in a rat surgical model.

Human esophageal adenocarcinoma (EAC) develops in a sequence from gastroesophageal reflux disease (GERD), columnar-lined esophagus (CLE), dysplasia, and eventually to EAC. We established a rat surgical EAC model with esophagogastroduodenal anastomosis (EGDA) to mimic the staged process of esophageal adenocarcinogenesis. Profiling of the AA metabolites with mass spectrometry showed that prostaglandin E2 (PGE2), leukotriene B4 (LTB4), 15-hydroeicosatetraenoic acid (HETE), 12-HETE, 8-HETE and 5-HETE all increased at the esophagoduodenal junction after EGDA as compared with the proximal esophagus, with PGE2 as the major metabolite. Consistent with this profile, cyclooxygenase 2 (Cox2) was overexpressed in the basal cell layer of esophageal squamous epithelium, CLE cells and EAC tumor cells of the EGDA rats, as compared with the normal esophageal epithelium. Sulindac (a Cox inhibitor), nordihydroguaiaretic acid (NDGA, a lipoxygenase inhibitor) and alpha-difluoromethylornithine (DFMO, an ornithine decarboxylase inhibitor) were tested for their possible inhibitory actions against the formation of EAC in the rat EGDA model. In a short-term study (for 4 weeks after surgery), dietary administration of both sulindac (300 and 600 p.p.m.) and NDGA (100 p.p.m.) effectively reduced the EGDA-induced inflammation. In a long-term chemoprevention study (for 40 weeks after surgery), 300 p.p.m. sulindac, alone or in combination with 100 p.p.m. NDGA or 0.5% DFMO, decreased the tumor incidence from 57.7 to 26.9%, or 16.7 or 20%, respectively (P < 0.05). NDGA alone (100 and 200 p.p.m.) slightly decreased the tumor incidence to 52.4 and 37%, respectively, although the difference was not statistically significant. DFMO alone did not show significant effects on tumor incidence. Inhibition of tumor formation by sulindac was correlated with lowered levels of PGE2. In conclusion, sulindac exerted its chemopreventive effect against the formation of EAC in the rat EGDA model possibly through its inhibition of Cox.

Circumscribed palmar or plantar hypokeratosis: A distinctive epidermal malformation of the palms or soles

Background: Epidermal malformations of the skin include a group of heterogeneous developmental defects that result from errors in morphogenesis of the epidermis during intrauterine life. Objective: The purpose of this study was to report the clinical and histopathologic features of a distinctive epidermal malformation involving the skin of the palms or soles. Methods: Ten patients were included in this study. All of them showed the same clinical features that consisted of a solitary circumscribed and circular area of erythematous depressed skin on the palm or on the sole. Diagnosis was confirmed by histopathologic study. Results: All patients were middle aged or elderly. Nine patients were women and one was a man. The lesions showed predilection for the skin of the thenar and hypothenar regions of the palm or the medial side of the sole. Histopathologic study demonstrated a depression of the epidermis, with a sharp stair between normal and involved skin. The epidermis covering the depression showed markedly thinner horny layer and a slightly diminished granular cell layer when compared with adjacent noninvolved skin. Keratinocytes of the squamous cell layer, granular cells, and corneocytes showed, otherwise, a normal appearance. Serial sections failed to demonstrate cornoid lamellation. Conclusion: On the basis of the clinical and histopathologic findings in these 10 patients, we have named this malformation circumscribed palmar or plantar hypokeratosis. This lesion seems to be a distinctive entity that has not been previously described. (J Am Acad Dermatol 2002;47:21-7.)