Ultrastructural Changes in Keratinizing Epithelium Following Trypsinization, Epidermal Detachment and Apposition to Mesenchymes

1970 ◽  
Vol 6 (2) ◽  
pp. 511-535
Author(s):  
H. M. JENSEN ◽  
N. K. MOTTET
Keyword(s):  
Basal Lamina ◽  
Quadriceps Tendon ◽  
Limb Bud ◽  
Ultrastructural Changes ◽  
Basal Cells ◽  
Tyrode Solution ◽  
Cellular Effects ◽  
Skin Explants ◽  
Cellular Shrinkage

The cellular effects of trypsinization, a commonly used method for separating epithelial from mesenchymal tissues, were examined with the electron microscope. Specimens were fixed after each step of the trypsinization process in 1 % OsO4 in double strength Tyrode solution and after 1-7 days of culture following reapposition of the epithelium to its own mesenchyme or collagen-rich 12-day embryonic quadriceps tendon. Controls consisted of specimens identically prepared from limb bud skin derived from the same site from 5-day normal embryos to hatching. A second series of controls were 5-day skin explants cultured for 1-7 days in vitro following identical preparation except for the omission of trypsin. Trypsin caused transient cytoplasmic protrusions (‘blebs’) on the deep aspect of the basal cells, cellular shrinkage and increase in lysosomes. The basal lamina was disrupted overlying the blebs and remained attached to the basal cells only between the blebs. Continuity of the basal lamina was restored within 24 h after the onset of culturing and developed precociously thereafter, regardless of whether it was reapposed to its own collagen-poor mesenchyme or the collagen-rich quadriceps tendon. In the latter, focal excessive basal lamina formation was observed. Epithelial cell differentiation proceeded equally precociously in trypsinized and non-trypsinized cultures. Disruption of the basal lamina by trypsinization did not produce detectable alteration in the synthesis of tonofilaments, desmosomes, granular reticulum or corpuscula cribriformia. Keratohyaline bodies were not found in any of the cultures and keratinized cells did not develop.

Ultrastructural changes of basal lamina and anchoring fibrils of gingiva in vitro

1973 ◽  
Vol 8 (3) ◽  
pp. 127-142 ◽  
Author(s):  
A. Sugimoto ◽  
G. G. Rose ◽  
H. Takarada ◽  
M. Cattoni
Keyword(s):  
Basal Lamina ◽  
Ultrastructural Changes

Ultrastructural Features of Defective in Vitro Keratinization of Chick Embryonic Skin

1970 ◽  
Vol 6 (2) ◽  
pp. 485-509
Author(s):  
H. M. JENSEN ◽  
N. K. MOTTET
Keyword(s):  
Hind Limb ◽  
Epidermal Differentiation ◽  
Limb Bud ◽  
Basal Cells ◽  
In Ovo ◽  
Electron Microscopic ◽  
Embryonic Skin ◽  
And Control ◽  
Chick Embryonic Skin

Thirty-four explants of epithelium and subjacent mesenchyme from the hind limb buds of 5-day chick embryos were cultured for 1 to 14 days. Controls consisted of a series of in ovo limb bud specimens from 5 day's incubation to hatching. Both experimental and control specimens were examined by similar electron-microscopic methods. Differentiation of epidermis was precocious and that of dermis extremely retarded in vitro, contrasting with the events in ovo where epidermal differentiation occurred later and differentiation of dermis was early and vigorous. The two types of epidermal cells developed to a different degree in vitro. Pericytes and their derivatives at times developed precociously and reached full maturity, although their pattern of differentiation was asynchronous compared with that in ovo. Basal cells and their derivatives produced filaments precociously but mature keratinized cells were not found. Absence of keratohyaline granules in the epithelial cells appeared to be the initial defect in the keratinization process. Hyperplasia of mitochondria in basal and parabasal cells was also noted. The underlying mesenchyme, which in ovo begins to produce large amounts of collagen at an exponentially accelerating rate at 5 days, synthesized only scant collagen under the in vitro conditions employed. The hypothesis is presented that the mesenchyme alters epithelial differentiation by affecting keratohyaline synthesis which in turn controls keratinization.

Induction and Differentiation of Dental Epithelium in Vivo and in Vitro

1982 ◽  
Vol 40 ◽  
pp. 142-145
Author(s):  
E. J. Kollar
Keyword(s):  
Connective Tissue ◽  
Oral Mucosa ◽  
Basal Lamina ◽  
Functional Derivatives ◽  
Specific Source ◽  
Dental Epithelium ◽  
Connective Tissue Stroma

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.

Ultrastructural Changes in Tumor Cells During Human Peripheral Blood Monocyte-Mediated Cytotoxicity

1981 ◽  
Vol 39 ◽  
pp. 452-453
Author(s):  
K. E. Muse ◽  
D. G. Fischer ◽  
H. S. Koren
Keyword(s):  
Target Cell ◽  
Human Peripheral Blood ◽  
Mononuclear Phagocytes ◽  
Ultrastructural Changes ◽  
Target Cells ◽  
Limited Information ◽  
Blood Monocytes ◽  
Tumoricidal Activity ◽  
Activated State

Mononuclear phagocytes, a pluripotential cell line, manifest an array of basic extracellular functions. Among these physiological regulatory functions is the expression of spontaneous cytolytic potential against tumor cell targets.The limited observations on human cells, almost exclusively blood monocytes, initially reported limited or a lack of tumoricidal activity in the absence of antibody. More recently, freshly obtained monocytes have been reported to spontaneously impair the biability of tumor target cells in vitro (Harowitz et al., 1979; Montavani et al., 1979; Hammerstrom, 1979). Although the mechanism by which effector cells express cytotoxicity is poorly understood, discrete steps can be distinguished in the process of cell mediated cytotoxicity: recognition and binding of effector to target cells,a lethal-hit stage, and subsequent lysis of the target cell. Other important parameters in monocyte-mediated cytotoxicity include, activated state of the monocyte, effector cell concentrations, and target cell suseptibility. However, limited information is available with regard to the ultrastructural changes accompanying monocyte-mediated cytotoxicity.

Ultrastructural Changes in Three Different Mammalian Cells Following Ultraviolet Laser Irradiation

1972 ◽  
Vol 30 ◽  
pp. 350-351
Author(s):  
K. Shankar Narayan ◽  
Kailash C. Gupta ◽  
Tohru Okigaki
Keyword(s):  
Ultraviolet Light ◽  
Mammalian Cells ◽  
Biological Effects ◽  
Survival Rates ◽  
Chinese Hamster ◽  
Cell Types ◽  
Differential Sensitivity ◽  
Ultrastructural Changes ◽  
Ultraviolet Laser

The biological effects of short-wave ultraviolet light has generally been described in terms of changes in cell growth or survival rates and production of chromosomal aberrations. Ultrastructural changes following exposure of cells to ultraviolet light, particularly at 265 nm, have not been reported.We have developed a means of irradiating populations of cells grown in vitro to a monochromatic ultraviolet laser beam at a wavelength of 265 nm based on the method of Johnson. The cell types studies were: i) WI-38, a human diploid fibroblast; ii) CMP, a human adenocarcinoma cell line; and iii) Don C-II, a Chinese hamster fibroblast cell strain. The cells were exposed either in situ or in suspension to the ultraviolet laser (UVL) beam. Irradiated cell populations were studied either "immediately" or following growth for 1-8 days after irradiation.Differential sensitivity, as measured by survival rates were observed in the three cell types studied. Pattern of ultrastructural changes were also different in the three cell types.

Ultrastructure of the basal lamina of bovine ovarian follicles and its relationship to the membrana granulosa

Reproduction ◽  
2000 ◽  
pp. 221-228 ◽  
Author(s):  
HF Irving-Rodgers ◽  
RJ Rodgers
Keyword(s):  
Basal Lamina ◽  
Granulosa Cells ◽  
Light And Electron Microscopy ◽  
Single Layer ◽  
Antral Follicle ◽  
Basal Cells ◽  
Preantral Follicles ◽  
Antral Follicles ◽  
Cellular Processes ◽  
Innermost Layer

Different morphological phenotypes of follicular basal lamina and of membrana granulosa have been observed. Ten preantral follicles (< 0. 1 mm), and 17 healthy and six atretic antral follicles (0.5-12 mm in diameter) were processed for light and electron microscopy to investigate the relationship the between follicular basal lamina and membrana granulosa. Within each antral follicle, the shape of the basal cells of the membrana granulosa was uniform, and either rounded or columnar. There were equal proportions of follicles </= 4 mm in diameter with columnar basal cells and with rounded basal cells. Larger follicles had only rounded basal cells. Conventional basal laminae of a single layer adjacent to the basal granulosa cells were observed in healthy follicles at the preantral and antral stages. However, at the preantral stage, the conventional types of basal lamina were enlarged or even partially laminated. A second type of basal lamina, described as 'loopy', occurred in about half the preantral follicles and in half the antral follicles </= 4 mm diameter. 'Loopy' basal laminae were not observed in larger follicles. 'Loopy' basal laminae were composed of basal laminae aligning the basal surface of basal granulosa cells, but with additional layers or loops often branching from the innermost layer. Each loop was usually < 1 microm long and had vesicles (20-30 nm) attached to the inner aspect. Basal cellular processes were also common, and vesicles could be seen budding off from these processes. In antral follicles, conventional basal laminae occurred in follicles with rounded basal granulosa cells. Other follicles with columnar cells, and atretic follicles, had the 'loopy' basal lamina phenotype. Thus, follicles have different basal laminae that relate to the morphology of the membrana granulosa.

scholarly journals Role of Jagged1-mediated Notch Signaling Activation in the Differentiation and Stratification of the Human Limbal Epithelium

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1945
Author(s):  
Sheyla González ◽  
Maximilian Halabi ◽  
David Ju ◽  
Matthew Tsai ◽  
Sophie X. Deng
Keyword(s):  
Notch Signaling ◽  
Progenitor Cell ◽  
Basal Layer ◽  
Notch Signaling Pathway ◽  
Basal Cells ◽  
Proliferation Markers ◽  
Limbal Epithelium ◽  
Asymmetric Divisions ◽  
Signaling Activation

The Notch signaling pathway plays a key role in proliferation and differentiation. We investigated the effect of Jagged 1 (Jag1)-mediated Notch signaling activation in the human limbal stem/progenitor cell (LSC) population and the stratification of the limbal epithelium in vitro. After Notch signaling activation, there was a reduction in the amount of the stem/progenitor cell population, epithelial stratification, and expression of proliferation markers. There was also an increase of the corneal epithelial differentiation. In the presence of Jag1, asymmetric divisions were decreased, and the expression pattern of the polarity protein Par3, normally present at the apical-lateral membrane of basal cells, was dispersed in the cells. We propose a mechanism in which Notch activation by Jag1 decreases p63 expression at the basal layer, which in turn reduces stratification by decreasing the number of asymmetric divisions and increases differentiation.

scholarly journals Pharmacological targeting of host chaperones protects from pertussis toxin in vitro and in vivo

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Katharina Ernst ◽  
Ann-Katrin Mittler ◽  
Veronika Winkelmann ◽  
Carolin Kling ◽  
Nina Eberhardt ◽  
...  
Keyword(s):  
Pertussis Toxin ◽  
Airway Epithelium ◽  
Whooping Cough ◽  
Apical Surface ◽  
Basal Cells ◽  
Pharmacological Chaperone ◽  
Infant Mouse ◽  
Novel Therapeutic Strategies

AbstractWhooping cough is caused by Bordetella pertussis that releases pertussis toxin (PT) which comprises enzyme A-subunit PTS1 and binding/transport B-subunit. After receptor-mediated endocytosis, PT reaches the endoplasmic reticulum from where unfolded PTS1 is transported to the cytosol. PTS1 ADP-ribosylates G-protein α-subunits resulting in increased cAMP signaling. Here, a role of target cell chaperones Hsp90, Hsp70, cyclophilins and FK506-binding proteins for cytosolic PTS1-uptake is demonstrated. PTS1 specifically and directly interacts with chaperones in vitro and in cells. Specific pharmacological chaperone inhibition protects CHO-K1, human primary airway basal cells and a fully differentiated airway epithelium from PT-intoxication by reducing intracellular PTS1-amounts without affecting cell binding or enzyme activity. PT is internalized by human airway epithelium secretory but not ciliated cells and leads to increase of apical surface liquid. Cyclophilin-inhibitors reduced leukocytosis in infant mouse model of pertussis, indicating their promising potential for developing novel therapeutic strategies against whooping cough.

scholarly journals Establishment of an in vitro model for analyzing mitochondrial ultrastructure in PRKN-mutated patient iPSC-derived dopaminergic neurons

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Mutsumi Yokota ◽  
Soichiro Kakuta ◽  
Takahiro Shiga ◽  
Kei-ichi Ishikawa ◽  
Hideyuki Okano ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Dopaminergic Neurons ◽  
Structural Changes ◽  
In Vitro Model ◽  
Induced Pluripotent Stem Cell ◽  
Substantia Nigra Pars Compacta ◽  
Ultrastructural Changes ◽  
Mitochondrial Morphology ◽  
Vitro Model

AbstractMitochondrial structural changes are associated with the regulation of mitochondrial function, apoptosis, and neurodegenerative diseases. PRKN is known to be involved with various mechanisms of mitochondrial quality control including mitochondrial structural changes. Parkinson’s disease (PD) with PRKN mutations is characterized by the preferential degeneration of dopaminergic neurons in the substantia nigra pars compacta, which has been suggested to result from the accumulation of damaged mitochondria. However, ultrastructural changes of mitochondria specifically in dopaminergic neurons derived from iPSC have rarely been analyzed. The main reason for this would be that the dopaminergic neurons cannot be distinguished directly among a mixture of iPSC-derived differentiated cells under electron microscopy. To selectively label dopaminergic neurons and analyze mitochondrial morphology at the ultrastructural level, we generated control and PRKN-mutated patient tyrosine hydroxylase reporter (TH-GFP) induced pluripotent stem cell (iPSC) lines. Correlative light-electron microscopy analysis and live cell imaging of GFP-expressing dopaminergic neurons indicated that iPSC-derived dopaminergic neurons had smaller and less functional mitochondria than those in non-dopaminergic neurons. Furthermore, the formation of spheroid-shaped mitochondria, which was induced in control dopaminergic neurons by a mitochondrial uncoupler, was inhibited in the PRKN-mutated dopaminergic neurons. These results indicate that our established TH-GFP iPSC lines are useful for characterizing mitochondrial morphology, such as spheroid-shaped mitochondria, in dopaminergic neurons among a mixture of various cell types. Our in vitro model would provide insights into the vulnerability of dopaminergic neurons and the processes leading to the preferential loss of dopaminergic neurons in patients with PRKN mutations.

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