Ultrastructural study of the mucosal layer of the adult albino rat ureter

The ureter is a dynamic organ rather than a simple conduit through which urine flows. The aim of the study was to explore the electron microscopic structure of the mucosa of the rat ureter in a trial for understanding the adaptive functional interactions between the urothelium and the different components found in the lamina propria. The mucosa of the ureter of 10 adult healthy male albino rats was studied under a transmission electron microscope. The rat ureter mucosa was formed of urothelium and lamina propria. The uroepithelium consisted of basal, intermediate, and apical umbrella cells. The cytoplasm of the basal cells contained few rounded vesicles with homogeneous content, bundles of microfilaments, and ribonucleoprotein particles. Besides basal cells, a few bundle cells were observed; these cells contained small dense bodies retained within large vacuoles. Desmosomal junctions interconnected the neighboring intermediate cells of the urothelium, and many rounded vesicles, mitochondria, and Golgi saccules appeared in their cytoplasm. The apical plasma membrane of the umbrella cells showed plaques and intervening hinge regions. Some rounded and many fusiform vesicles appeared within their cytoplasm. The lamina propria contained many capillaries in concavities formed by the basal layer of the urothelium; their lining endothelial cells were unusually thick. Many telocytes appeared in close contact and encircled the blood capillaries and groups of nerve fibers in the lamina propria. The telocytes were interconnected with each other and with other connective tissue cells by their telopodes. The lamina propria also revealed immune cells such as eosinophils and mast cells. Morphological analysis of the ureter mucosa is providing clues how epithelial cells sense different stimuli and transduce-in these stimuli into the underlying nervous, vascular, and active cellular elements in the lamina propria

Histological study of megakaryocytogenesis and thrombocytogenesis in the guinea pig bone marrow with reference to the role of adipocytes

Blood platelets play a pivotal role in hemostasis and participate directly in thrombosis and atherosclerosis. The aim of the study was to investigate the steps of platelet production, the morphological changes that occur during proplatelet production, the cytoskeletal mechanics that drive these transformations, and the possible role of stromal cells in platelet formation. Red bone marrow fragments were harvested from ten adult male guinea pigs. Toluidine blue-stained semithin sections were prepared for light microscopic examination, and ultrathin sections were examined by transmission electron microscope. In the semithin sections of the bone marrow, nearly half of the area contained hematopoietic cells, whereas the remainder was occupied by adipocytes that showed unusual bridging connections between them. In addition, the megakaryocytic lineage cells assumed a unique close association with the neighboring adipocytes. Under transmission electron microscope, the surface of the immature megakaryocytes was characteristically smooth, whereas mature megakaryocytes developed characteristic proplatelets in the form of coarse surface cytoplasmic processes that bulged to the outside and detached as preplatelets. Granules and membranes associated with microtubules were translocated from the base of proplatelets to appear in their cytoplasm, and the invaginated membrane system became extensive in the mature megakaryocytes. Sometimes, these cells extended large proplatelets through the attenuated sinusoidal walls, where they discharged preplatelets that further fragmented into platelets. The formation of proplatelets and the elaboration of granules into the newly formed preplatelets and platelets were largely dependent on the efficiency of microtubular cytoskeletal elements. Marrow stromal cells, especially adipocytes, might be involved in megakaryocytic lineage development

adverse effects of bisphenol 'A' on some reproductive organs of the male albino rat: a light and electron microscopic study

Background: Bisphenol A [BPA] is a xenoestrogen [environmental estrogens] used in the production of polycarbonate plastics and epoxy resins that line food and beverage cans. Modernization of the Arabian Gulf region has resulted in the wide consumption of readymade foods that are packed in plastic containers and cans. Consequently, the majority of humans, particularly infants and children, are being continuously exposed to it

Aim of work: The objective of the present study was to examine the effect of exposure to BPA on the testis, epididymis, prostate, and penile corpora of adult albino rat

Materials and methods: One, 4, and 8 weeks following a subcutaneous injection of 150 microg BPA/kg body weight into adult albino rats every other day for 12 days, the histopathological changes induced in the testis, epididymis, prostate, and penile corpora were detected using both light and transmission electron microscopic techniques

Results: In BPA-treated animals, seminiferous tubules showed a decreased thickness of germinal epithelium with vacuolar degeneration and increased apoptotic cells. Sperm were hardly seen till the eighth week, when spermatogenesis was regained, but spermatids and mature sperm still had residual malformations. The rough endoplasmic reticulum cisternae of prostatic parenchyma appeared distended with a homogeneous content whereas most of the secretory vesicles were empty. In the penile corpora of BPA-treated groups, both tunical thickness and trabecular smooth muscle content were increased with consequent narrowing of sinusoidal spaces

Conclusion: These results suggest that BPA inhibits spermatogenesis, increases the ratio of sperm anomalies, and has a potential harmful effect on erectile function, which raises an alarm to the harmful effects of environmental contaminants that might cause subfertility or infertility

Ultrastructural study on microfold cells and microvillus cells in the follicle-associated epithelium over Peyer's Patches in albino rat

Microfold cells [M cells] act as gateways to the mucosal immune system. The aim of the study was to perform a detailed ultrastructural study on M cells and microvillus enterocytes in the follicle-associated epithelium that covers the dome region of the ileal Peyer's patches in the albino rat to understand the relationship between the two types of cells, the origin of M cells, and their possible mechanism in sampling of the luminal antigens. The follicle-associated epithelium over the Peyer's patches in 10 adult albino rats was studied carefully under transmission electron microscope with a special attention to M cells and microvillus enterocytes. M cells were characterized by pale cytoplasm and either paucity or lack of apical microvilli beside intracytoplasmic pockets harboring migrating lymphocytes. In the microvilli-lacking areas, however, bundles of microvillus filaments occasionally remained in the apical cytoplasm and small vesicles and tubules were found at the apical poles of M cells. Microvillus cells had apical brush borders composed of long, regular, and densely packed microvilli; however, a wide range of diversity of the apical surface morphology was noted. Sometimes, transitional epithelial cells from microvillus to M cells were observed as columnar cells, which had microvilli of moderate height in their apical border with appearance of bare areas, in addition to other cells, which had a microfolded profile that bore few stout and short microvilli. Pale cytoplasmic extensions of dendritic morphology were seen extending among the epithelial cells covering the Peyer's patches. The M cells were differentiated from the intestinal enterocytes by distinctive ultrastructural features. The observed transitional epithelial cells might indicate that the M cells probably originated from the microvillus enterocytes. The M cells transport the antigens from the intestinal lumen to the lymphocytes in the intraepithelial pockets for induction of mucosal-associated immune response

validation of photoshop based quantitative analysis of digital electron micrographs of developing erythrons

Erythrons are organized into erythroblastic islands. Tracing the course of cellular differentiation requires a reliable method for quantification of the morphological characteristics of these cells as they are prone to adopting highly changing phenotypes. The primary objective of this study was to show the applicability of Adobe Photoshop software in cytomorphometry, and the second objective was to summarize the ultrastructural characteristics of the cells forming the erythroblastic islands. Ultrathin sections of bone marrow were prepared from 10 albino rats and then the digitized electron microscopy images of erythrons were stored. Adobe Photoshop was used to measure the cytomorphometric parameters in the electron micrographs of these developing cells. The area occupied by any cellular component could be specified and compared directly from the histogram using the 'Magnetic Lasso Tool'. The area pixel size and luminosity of all pixels within the selected area were recorded and the data were subjected to statistical analysis. The study reports a straightforward pixel-based cytomorphometric method that gives objective information about pixel values of area size and luminescence. The recorded analytical values of a nucleated erythron differed significantly from those of its preceding stage, and the average cytoplasmic luminosity of mature RBCs was 67.62% that of reticulocytes. In addition, the developmental features of erythrons were explored. When the input material is standardized, Adobe Photoshop gives affordable and accurate measurement options that may be available for a diverse range of histomorphometric applications

Age-related changes in the ocular lens of the albino rat: a light and scanning electron microscopic study

The eye lens is a minute organ with a complex structure that plays an indispensible role in the process of vision. The study was conducted to detect-age related structural changes that occur in the rat ocular lens and to correlate these changes with the development of senile cataract. Fifteen male albino rats were used in this study. They were divided into three groups: young, adult, and aged [1, 6 and 18 months, respectively]. The animals' lenses were removed, dissected, and processed for light and scanning electron microscopy. The width, thickness, and number of lens fibers were assessed using an image analyzer. Statistical analysis of data was carried out using analysis of variance and the Student t-test. In H and E stained sections, the lens of aged rats was seen to be covered by a thick capsule and had a double layer of epithelial cells. The aged lens showed marked disorganization and vacuolation of nuclear fibers. Scanning electron microscopic study revealed irregularities of the lateral borders of the cortical fibers, folding of their surfaces, and few ball and socket interlocking patterns. The nuclear fibers showed microplicae with a decrease in their cross-sectioned areas. Statistical analysis revealed a significant increase in the number and width of the aged nuclear lens fibers and as significant decrease in their thickness, compared with younger ones. Lens fibers undergo some structural changes as a result of aging in the form of irregularities in shape and arrangement, thinning and compaction. These changes could be correlated to age-related optical problems such as senile presbyopia and cataract

Ultrastructural study of the adult albino rat parotid gland with special reference to the role of stromal telocytes

The parotid glands are considered to be the most frequent sites for salivary gland tumors. The aim of this study is to shed light on the ultrastructural features of the albino rat parotid gland including the stromal telocytes. Ten adult male albino rats were used in this study; fine pieces of the parotid glands were processed for electron microscopic examination. Semithin sections were stained with toluidine blue and were examined to select the proper sites for ultrathin sections. The parotid gland parenchyma was formed of a mixture of secretory acini and ducts. The acini were composed almost exclusively of serous-secreting cells. Some acinar cells contained large lipofuscin granules. Each intralobular duct had two parts: a proximal intercalated part and a distal striated part. Over most of the length of the intercalated duct, the cytoplasmic organelles were scanty and poorly developed. Near the striated portion, the epithelial cells became taller and richer in mitochondria. Rare dark cells with many processes projecting from their lateral surfaces were observed. Small cells with a characteristic dendritic morphology were frequently observed within the epithelium of the ducts and between the serous acini. Stromal telocytes had very long and thin moniliform prolongations [telopodes] that showed thin segments [podomeres] alternating with dilatations [podoms] rich in caveolae. Telocytes created a network with the blood and lymphatic capillaries. Elements of this network were probably interacting with other cell types. These interactions were achieved either by direct contact or mediated through shedding of microvesicles. Telocytes were detected in the interacinar and the periductal stroma outside the basal lamina; they might be involved in intercellular signaling. This would indicate that these cells might modulate the parotid function