PAS-positive Basement Membrane Research Articles

Morphological characteristics of vasculogenic mimicry and its correlation with EphA2 expression in gastric adenocarcinoma

Genetically deregulated tumor cells generate vascular channels by vasculogenic mimicry (VM) that is independent of endothelial blood vessels. The morphological characteristics of VM and the role of EphA2 in the formation of VM were evaluated in 144 clinical samples of gastric adenocarcinoma and AGS gastric cancer cell line. It has long been believed that VM consists of PAS-positive basement membrane and CD31/CD34-negative cells. Interestingly, we found that the luminal surface of gastric tumor cells that form VM channels showed PAS-positive reaction, and that the involvement of CD31/CD34-positive tumor cells in the formation of VM channels. Highly aggressive tumor cells that formed VM were found to express CD31 or CD34, implicating the angiogenic and vasculogenic potential of the genetically deregulated tumor cells. VM occurrence was positively correlated with high expression of EphA2 in our patient cohort, and the indispensable role of EphA2 in VM formation was identified by gene silencing in AGS cells. We also report that Epstein–Barr virus (EBV)-positive tumor cells were involved in the formation of VM channels in EBV-associated gastric cancer samples. Overall, our results suggest that EphA2 signaling promotes tumor metastasis by inducing VM formation during gastric tumorigenesis.

Myocardial epithelial inclusions in a Holstein calf

Summary Epithelial inclusions were detected in myocardium of a 2-month-old male Holstein calf. Microscopically, nonpurulent myocarditis along with focal tubular and acinar structures covered with cuboidal epithelial cells was seen in the myocardium. Most tubular and acinar structures stained with Masson’s trichrome were found to be surrounded with a dense collagen. Tubular and acinar structures had PAS positive basement membrane. Immunohistochemical staining revealed that tubular and acinar structures were both vimentin and pancytokeratin positive, while the connective tissue was only vimentin positive.

Histopathology of insulin‐induced laminitis in ponies

Ponies with laminitis associated with insulin resistance and hyperinsulinaemia lack systemic and/or intestinal inflammatory signs, suggesting a different pathogenesis potentially reflected in differing histopathology. To describe the histological appearance and quantify morphological changes in primary and secondary epidermal lamellae (PEL and SEL) of laminitis lesions from ponies with insulin-induced laminitis. Equine hoof lamellar tissue was obtained from 4 control ponies and 5 ponies with laminitis induced following infusion of insulin (1036 ± 55 µU/ml) while maintaining euglycaemia for 55.4 ± 5.5 h. Sections from all 4 hooves were stained and examined by a veterinary pathologist. Measurements of lamellar length (PEL and SEL) were made in mid-dorsal sections of the right forefeet by 2 blinded observers. Immunolabelling for calprotectin was performed using a monoclonal antibody. No lesions were detected in normal ponies. Lesions detected in ponies with laminitis were variable in severity between ponies. Within ponies, SEL lesions were more severe along the axial region of PEL. Lesions included swelling, disorganisation and abnormal keratinisation of epidermal cells, increased mitotic activity and apoptosis. Separation of basement membranes was minimal. Immunostaining revealed inflammatory cells within the lamellar dermis. SEL were significantly elongated in laminitic hooves relative to controls, with the greatest elongation in those attached to abaxial and middle regions of PEL. Laminitis induced by prolonged infusion of insulin lacked widespread basement membrane disintegration, and increases in epidermal cellular proliferation at axial aspects were marked for this acute stage of disease. Defining equine laminitis entirely in terms of separation of the basement membrane may not be appropriate for laminitis associated with hyperinsulinaemia.

Metastatic Iridociliary Adenocarcinoma in a Labrador Retriever

An enucleated left eye from a 15-year-old female spayed Labrador Retriever was received by the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) for histopathologic evaluation. Routine histologic preparation included staining with hematoxylin and eosin, and with alcian blue periodic acid-Schiff (PAS). At necropsy 9 months later, all grossly abnormal tissues (ipsilateral orbit and lung) were submitted to the COPLOW for histopathologic evaluation. Histopathologic evaluation of the globe revealed extensive invasion of the uvea and sclera by a pleomorphic cell population that formed disorganized cords and exhibited PAS-positive basement membrane material. Necropsy revealed a morphologically similar tumor in the ipsilateral orbit and lung. On immunohistochemical examination, the intraocular tumor stained diffusely immunopositive for vimentin, S-100, and neuron-specific enolase and multifocally, sparsely immunopositive for cytokeratin AE1/AE3. The orbital and thoracic tumors stained positively for vimentin but negatively for cytokeratin AE1/AE3. There are few reports of canine metastatic iridociliary adenocarcinoma in the literature; this is the first with immunohistochemical analysis.

CD31 and CD34 Expression as Immunohistochemical Markers of Endothelial Transdifferentiation in Human Cutaneous Melanoma

Introduction: Vasculogenic mimicry, as previously described in aggressive melanoma, is characterized by the de novo generation of intratumoral patterned vascular channels, composed of PAS-positive basement membrane in the absence of endothelial cells, providing additional microcirculation, in support to the classic tumoral angiogenesis. Methods: We investigated the immunohistochemical expression of two endothelial markers, CD31 and CD34, in tumoral cells of 60 melanomas (45 primary cutaneous and 15 metastatic) as possible evidence of vasculogenic mimicry. In addition we investigated the relationship between CD31 and CD34 expression and three pathological markers such as Clark’s level, and skin ulceration, predictive of melanoma’s aggressive behaviour, and mitotic index. Results: No cases of common melanocytic nevi immunoreacted with CD31 or CD34. Random CD31 immunoreactivity was present in 6% of Clark’s level I/II, 50% of Clark's level III and 80% Clark's level IV/V. CD34 was negative in Clark's level I/II but randomly stained the 20% and 55% of level III and IV/V respectively. 66% (10/15) of metastatic melanomas were CD31 positive showing a canalicular immunostaining pattern, conversely CD34 expression was never found. 7/8 cutaneous ulcerated melanomas immunostained for CD31 and 4/8 for CD34. CD31 immunostained 88% high/intermediate MI, and 53% of low MI melanomas. CD34 decorated the 29% of high/intermediate and 38% of low MI melanomas. Conclusions: CD31 and CD34 immunoreactivity closely parallel both the different morphologic steps of melanocytic tumor progression and the presence of histological parameters related to the aggressive behaviour. Their expression could be related to endothelial transdifferentiation of melanoma cells although a consequent functional role has not been demonstrated yet.

Histochemical analysis of pathological alterations in oral lichen planus and oral lichenoid lesions

Lichen planus is a dermatologic disease of unknown etiology characterized by keratotic plaques on the skin. Many patients also harbor white lesions of the oral mucosa. The literature contains numerous reports of lichen planus-like lesions evolving in conjunction with the administration of a variety of pharmacologic agents. It is difficult, if not impossible, to distinguish such lesions from one another. The present study evaluated the epithelial and basement membrane thickness, mast cells (intact cells and degranulated cells subepithelially) and the presence or absence of blood vessels in oral lichen planus and oral lichenoid lesions. The evaluation was done using the periodic acid-schiff (PAS) and toluidine blue staining techniques on 20 cases each of oral lichen planus and oral lichenoid lesions and 5 control specimens of normal buccal mucosa. The results showed an increased number of degranulated mast cells in areas of basement membrane degeneration, increased vascularity and increased PAS-positive basement membrane thickness in oral lichen planus as compared with oral lichenoid lesions. Reduced epithelial thickness was found in oral lichen planus. The present study emphasizes the importance of these parameters in differentiating oral lichen planus from oral lichenoid lesions using special staining techniques.

Large Cell Calcifying Sertoli Cell Tumor of the Testis

Large cell calcifying Sertoli cell tumor (LCCST) is a rare testicular tumor, usually occurring in young men before the age of 20. Ultrastructural study has been performed rarely demonstrating Sertoli cell features. We report a case of LCCST in a 7-year-old boy. A well-circumscribed yellowish-tan, 1.5-cm-sized mass was located within the left testicular parenchyma. The cut surface was somewhat resilient with multiple calcifications. On microscopic examination, the tumor was composed of large eosinophilic polygonal cells with abundant eosinophilic cytoplasm arranging in solid tubular and trabecular patterns, superficially mimicking Leydig cell tumor. However, there were multiple calcifications and the tumor cell nests were surrounded by PAS-positive basement membrane. Ultrastructural examination revealed the features of the Sertoli cell with Spangaro's crystals. The right testis showed a normal appearance by ultrasonogram and there were no other clinical features associated with Carney syndrome.

Relationship between epithelial and connective tissues in the stomach of the frog Rana temporaria during metamorphosis: an ultrastructural study

In the course of metamorphosis of the stomach of Rana temporaria tadpoles there is a marked increase in the amount of active mesenchymal fibroblasts and extracellular matrix underlying the regenerating gastric epithelium. At the onset of metamorphosis, a thick PAS-positive basement membrane is developed around the epithelial component of the mucosa, formed by the apical, degenerating larval epithelium and the basal, regenerative epithelial cords. Under the electron microscope, a folded basement membrane is usually revealed under the apical degenerating epithelium while a compact basement membrane (up to 1–2 μm thick), forming both patches and more extensive areas, is frequently seen around the regenerative glandular cords. Cytoplasmic processes, extending from both the epithelial and mesenchymal fibroblastic cells, cross the basement membrane and make physical contact between the two cellular types. At mid-metamorphosis, areas of thick PAS-positive basement membrane are still observed around the differentiating glandular outlines, before disappearing completely at late metamorphosis. The probable involvement of intertissue interactions between epithelium and connective elements in the morphogenesis, proliferation and differentiation of secondary, definitive frog stomach is discussed. Early contacts between epithelium and phagocytes, probably related to the invasion of epithelium by the phagocytic cells, have also been observed.

The use of immunohistochemistry and the polymerase chain reaction for detection of feline leukemia virus and feline sarcoma virus in six cases of feline ocular sarcoma.

Ocular sarcoma was diagnosed by light microscopic examination in enucleated globes (n = 4), orbital tissue biopsy (n = 1) and ocular evisceration contents (n = 1) from six cats. To determine if feline leukemia virus (FeLV) or a replication-defective FeLV, feline sarcoma virus (FeSV), was present in these ocular sarcomas, immunohistochemistry (IHC) and polymerase chain reaction (PCR) for FeLV were utilized. Immunohistochemical staining for FeLV glycoprotein 70 (gp70) was performed on all six formalin-fixed, paraffin-embedded tumors using an avidin-biotin complex technique. DNA was extracted from each specimen and a 166 bp region of the FeLV long-terminal repeat (LTR) was amplified by PCR. All tumors were composed primarily of spindle cells; two neoplasms had PAS-positive basement membrane enveloping areas of spindle cells. All tumors involved the uvea and five of six tumors showed transcleral extension, one of which invaded the optic nerve. Immunohistochemical staining for FeLV gp 70 was negative. PCR to amplify a portion of the FeLV LTR was negative. Based on these findings of these limited number of cases, FeLV/FeSV may not play a role in the tumorigenesis of feline ocular sarcomas. However, additional tumors representing all morphological subtypes should be investigated for the presence of viral antigen and DNA. It is important to determine the etiology and pathogenesis of these malignant ocular sarcomas. If the cell of origin and pathogenesis involve ocular and lenticular injury, and FeLV/FeSV is not present, then the clinical management of cases of feline ocular trauma, uveitis and glaucoma may prevent the development of this tumor.

Transient bullous dermolysis of the newborn

A case of transient bullous dermolysis of the newborn is reported. A healthy Hispanic newborn developed bullae during the first two days of life. From age two to four weeks, the lesions healed with milia formation. There was no residual scarring or hypopigmentation. An induced blister showed dermal-epidermal separation with the PAS-positive basement membrane in the epidermal roof. PAS-positive inclusions were present in the cytoplasm of a few basal cells. Examination by electron microscopy showed degeneration of the collagen and anchoring fibrils. There were numerous stellate inclusions in the endoplasmic reticulum of the cytoplasm of the lesional basal keratinocytes.

Endothelial Reaction to Perforating and Non-Perforating Excimer Laser Excisions in Rabbits

With an ArF excimer laser (193 nm, 750 mJ/cm2, 20 Hz) and a special slit-mask system, perforating and non-perforating linear keratectomies were performed in 55 rabbit corneas with a follow-up from 1 hour to 6 months. Varying the pulse number according to ablation rate (0.8 micron/pulse) and corneal thickness, four linear radial excisions (3 mm length, 70 microns width) of increasing depth (70%, 80%, 90%, 100% perforation) were produced. The corneas were processed for light microscopy, scanning and transmission electron microscopy, and vital staining of the endothelium. Except for mild cell contact alterations and discrete single cell damage in the 90% deep excisions, no endothelial damage could be detected after non-perforating keratectomies. Minute (less than 20 microns) and small (20 to 100 microns maximal diameter) perforations induced cell enlargement, formation of pseudopodia, rosette-like figures, multi-nucleated giant cells, and ultimately uniform reformation of the cell pattern (1 hour to 7 days postoperatively). Larger excimer laser defects of Descemet's membrane (greater than 100 microns) were overgrown by dedifferentiated endothelial cells producing a new PAS-positive basement membrane. Vital staining revealed the complete and stable reorganization of the endothelium over these lesions within 6 months. Our observations are similar to those reported on the endothelial repair process following other surgical manipulations (knife incisions, direct Nd:YAG-laser trauma) and support the applicability of excimer lasers for corneal trephination in patients.

Primary cutaneous adenoid cystic carcinoma: ultrastructural study and immunolocalization of Types I, III, IV, V collagens and laminin

A primary adenoid cystic carcinoma of the skin is reported. Light microscopy revealed pseudocysts. PAS-positive basement membrane and true glandular lumen, which in aggregates are specific for adenoid cystic carcinoma. Perineural invasion was also observed. Ultrastructural examinations revealed three types of cystic spaces; pseudocysts, true glandular lumens and intercellular spaces. Enzyme histochemical examinations showed positive reactions for eccrine enzymes, including phosphorylase and succinic dehydrogenase and negative for apocrine enzymes. Immunolocalization of collagens and laminin revealed that basement membranes of the pseudocysts involve Type V collagen as well as Type IV collagen and laminin.

Histopathology of Gottron's papules.

We studied Gottron's papules in 11 cases of known dermatomyositis to determine whether the findings were similar to those in the poikilodermatous eruption usually biopsied in this disease. As in typical poikilodermatous dermatomyositis, basal layer vaculopathy, PAS-positive basement membrane thickening, upper dermal mucin deposition and a mild diffuse upper dermal mononuclear infiltrate were frequent findings. In contrast to poikilodermatous dermatomyositis, however, epidermal hyperplasia consisting of acanthosis or papillomatosis was often present and epidermal atrophy was rare. We conclude that a specific diagnosis of dermatomyositis can often be made on biopsy of a Gottron's papule.

Histochemical and ultrastructural analysis of developing adipocytes in the fetal pig.

Histochemical and ultrastructural aspects of adipocyte differentiation in subcutaneous tissue of fetal pigs were analyzed in a longitudinal study. A matrix of collagen fibers surrounding adipocytes developed after the establishment of a distinct and continuous PAS-positive basement membrane. The degree of plasma membrane invagination and specialization was positively correlated with the extent of basement membrane and collagen matrix formation. Close spatial relationships between narrow, smooth endoplasmic reticulum, plasma membrane invaginations, the surface of lipid droplets and mitochondria were observed in differentiating adipocytes. Histochemical and ultrastructural criteria for the identification of preadipocytes are: (1) perivascular location; (2) mitochondria localized in the Golgi zone; (3) cytosolic glycogen; (4) rough endoplasmic reticulum with cisternae uniformly and approximately 600 A wide; (5) free ribosomes and few polysomes, and (6) lipid droplets encased by microfilaments. These criteria permitted clear distinction from obvious fibroblasts and macrophages. Other stromal cells were morphologically abnormal. Occasionally, adipocytes and perivascular cells exhibited close intercellular contacts that were morphologically distinct from intercellular contacts between contiguous endothelial cells.

Phakomatous Choristoma of the Lower Eyelid with Psammoma Body Formation: A Light and Electron Microscopic Study

A firm, round tissue mass, measuring approximately 12 mm in diameter, was excised from a 5-month-old boy who had a history of a gradually enlarging swelling in the left lower nasal eyelid since birth. Histologically and ultrastructurally, the lesion appeared benign and was composed of a dense connective tissue stroma in which nests, lobules, tubules, cords, and sheets of large, pale-staining cuboidal and elongated epithelial cells were surrounded by an irregular, thick PAS-positive basement membrane having focal excrescences. The interior of the epithelial islands contained “bladder” cells, cellular debris, granuloamorphous material, and foci of dystrophic calcification; an unusual feature of the lesion was the formation of numerous psammoma bodies. Tumors of lenticular anlage are rare and probably result due to displacement or migration of the inferior lens placode cells; alternatively, it may originate from an additional locus of lens vesicle in the primitive surface ectoderm of the lower lid. The lesion enlarges because of the differentiation of the ectopic lenticular cells in an abortive attempt to form a lens within the extraocular and mesodermal environment of the lid.

Histological studies on the testicular seminal pathway and changes in the epididymis of the camel (<i>Camelus dromedarius</i>)

The testicular seminal pathway in the camel is divided into two portions: an intratesticular and an extratesticular portion. The intratesticular seminal pathway consists of three portions: a 'tapering terminal segment' of the seminiferous tubules opening into the receptacle, the tubuli recti with three parts and the rete testis. The extratesticular portion consists of the rete testis, as an extension of the intratesticular portion and an elongated sac from which 6-7 ductuli efferentes originated. The tapering terminal segments are lined by modified Sertoli cells. Both, the tubuli recti and rete testis, are lined by simple cuboidal to columnar cells. The epithelium of the ductuli efferentes which, at its origin from the sac is simply cuboidal, gradually changes to an epithelium that consists of alternating groups of high-columnar ciliated and low-columnar non-ciliated cells. The strongly PAS-positive basement membrane of the ductuli efferentes is surrounded by a thin circular layer of smooth muscle fibres. The pseudo-stratified columnar epithelium of the epididymis is supported by an intensely PAS-reactive basement membrane. Morphological changes in the epithelium of the head and body regions of the epididymis due to seasonal variations are well marked in the camels of all age groups.

Skin microvascular lesions in chronic diffuse hepatic diseases.

Smmary Skin biopsies obtained from the hand have been evaluated by histological and histochemical techniques, in twenty patients with a confirmed diagnosis of chronic diffuse hepatopathies and in ten healthy controls. In patients with chronic hepatic disease, skin biopsies show microvascular lesions, characterized by thickening of the PAS-positive basement membrane and endothelial alterations, similar to those found in diabetic patients. These lesions did not exist in the healthy control group.

Histochemical and electron microscopical study of the bulla from porphyria cutanea tarda.

The blister from Porphyria cutanea tarda, which histologically appears as a subepidermal lesion, is histochemically not always localised underneath the PAS-positive basement membrane.

Basement membrane in hepatic coccidiosis of the rabbit

The changes of the basement membrane of intrahepatic bile ducts in the evolution and regression of the papillomatous reaction induced by Eimeria stiedae were studied on 40 young rabbits using a histological and immunofluorescent methods. The results showed that a PAS-positive basement membrane could be demonstrated in the early stages of the papillomatous transformation and that its thickness increased remarkably in the fully developed stage of papillomatous evolution which paralleled the active stage of gametogony. The membrane usually remained thickened throughout the course of epithelial regression and regeneration. There was a localization of fluoro-conjugated goat and anti-rabbit globulin immunoglobulin in the thickened basement membranes beginning at the early stage of gametogony. This evidence suggests that progressive thickening of the basement membranes of the infected bile ducts was mainly aimed at supporting the hyperplastic papillary epithelium and the altered basement membrane after degeneration and/or necrosis of the infected papillary epithelium in the stage of regression assisted the orientation of the newly formed epithelial cells in the process of healing. There is no convincing evidence that a thickened basement membrane or a deposition of globulin as such could strengthen the local defence mechanism to any significant extent.

Epidermolysis Bullosa Hereditaria Dystrophica et Polydysplasticaの1重症例

A baby girl, at the age of 5 days, has had a widespread bullous eruption and defect of epithelium involving the mouth, elbows, feet, knees, and ankles, since her birth. The nails were thickened and clawlike. There is no family history of this condition. The baby was quite well nourished, and at first, three was some improvement, but fresh bullae continued to appear. She stopped eating and lost weight, and died at the age of 82 days, autopsy was performed. Autopsy findings: The death of the patient was due to bronchopneumonia directly. The significant microscopic changes were hypoplasia of the thymus, lymphfollicls of the spleen and other lymp happaratus. Histopathologic specimen of the skin showed that the bullae were formed between the epidermis and the corium. PAS-positive basement membrane was located on the side of the epidermis, not corium. We think that epidermolysis bullosa hereditaria dystrophica et polysplastica in the newborn have to be differentiated from epidermolysis bullosa letalis clinically or histologically.