STEM Cells and Liver Carcinogenesis: Contributions of Light, Confocal and Electron Microscopy

1997 ◽  
Vol 3 (S2) ◽  
pp. 3-4
Author(s):  
P. M. Novikoff ◽  
A. Yam
Keyword(s):  
Electron Microscopy ◽  
Partial Hepatectomy ◽  
Cell Lineage ◽  
Cell Types ◽  
Liver Carcinogenesis ◽  
Hepatic Parenchyma ◽  
Hepatocyte Regeneration ◽  
Bile Ductule ◽  
Parenchymal Hepatocytes ◽  
Confocal And Electron Microscopy

Three cell types not previously described were revealed by the application of several microscopic procedures in combination with cytochemistry and irnmunocytochemistry in the livers of rats treated according to the Solt et al carcinogenesis protocol. This protocol consists of the administration of an initiating carcinogen (diethynitrosamine), a mitoinhibitory carcinogen, (acethylaminofluorene) and a growth stimulus (partial hepatectomy) (1). Two of the cell types were found in intrahepatic bile ductules and one within the connective tissue stroma surrounding the ductules. These findings have implications for understanding the cell lineage pathways that operate in an experimental rodent hepatocarcinogenesis system in which hepatocyte regeneration is inhibited and in which preneoplastic nodules and hepatomas develop. Our previous studies have determined some of the enzymatic, antigenic and structural properties of these cell types and their interrelations to each other, to parenchymal hepatocytes and to preneoplastic nodules (2).Proliferation of bile ductule cells occurs early (24-48 hrs) after the partial hepatectomy step of the protocol with extensive branching of the ductules into the hepatic parenchyma.

scholarly journals Stem Cells and Rat Liver Carcinogenesis: Contributions of Confocal and Electron Microscopy

1998 ◽  
Vol 46 (5) ◽  
pp. 613-626 ◽  
Author(s):  
Phyllis M. Novikoff ◽  
Ana Yam
Keyword(s):  
Epithelial Cells ◽  
Connective Tissue ◽  
Cell Lineage ◽  
Microscopic Analysis ◽  
Cell Types ◽  
Nodule Formation ◽  
Surrounding Connective Tissue ◽  
Multiple Cell ◽  
Polarized Epithelial Cells ◽  
Parenchymal Hepatocytes

Microscopic analysis in combination with cytochemistry and immunocytochemistry has revealed the presence of four cell types not previously described in the portal area and parenchyma of the liver from an experimental rodent hepatocarcinogenic rat model. Within the intrahepatic bile ductules, which proliferate after administration of chemical carcinogens and partial hepatectomy, small, undifferentiated nonpolarized, nonepithelial cells with a blast-like phenotype and polarized epithelial cells different from the polarized epithelial cells that typically line the walls of the bile ductules were found. In the connective tissue stroma surrounding the bile ductules, nonpolarized epithelial cells with hepatocyte phenotype were found. In the parenchyma, subpopulations of bile ductule epithelial cells that established ATPase-positive bile canalicular structures, including the formation of desmosomes and tight junctions, with parenchymal hepatocytes within the hepatic lobule were found. These observations raise the following questions in this model. Are there undifferentiated progenitor cells with stem cell-like properties within bile ductules? What are the interrelations of the newly described cell types with each other, with parenchymal hepatocytes, with preneoplastic nodules, and with hepatomas? Do the heterogeneous cell types within the bile ductules, in the surrounding connective tissue, and within the hepatic cords represent intermediate stages of single or multiple cell lineage pathways leading to hepatocyte differentiation, liver regeneration, and/or preneoplastic nodule formation?

Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 118-119
Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun
Keyword(s):  
Electron Microscopy ◽  
Structural Organization ◽  
Cell Types ◽  
Structural Features ◽  
Molecular Architecture ◽  
The Past ◽  
Keratin Filaments ◽  
Different Types ◽  
10 Nm Filaments ◽  
Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

Electron Microscopy in the diagnosis of lysosomal storage diseases

1989 ◽  
Vol 47 ◽  
pp. 866-867
Author(s):  
Carole Vogler ◽  
Harvey S. Rosenberg
Keyword(s):  
Electron Microscopy ◽  
Lysosomal Enzyme ◽  
Rectal Mucosa ◽  
Lysosomal Storage Diseases ◽  
Cell Types ◽  
Lysosomal Storage ◽  
Storage Material ◽  
Ultrastructural Examination ◽  
Blood Leukocytes ◽  
Storage Diseases

Diagnostic procedures for evaluation of patients with lysosomal storage diseases (LSD) seek to identify a deficiency of a responsible lysosomal enzyme or accumulation of a substance that requires the missing enzyme for degradation. Most patients with LSD have progressive neurological degeneration and may have a variety of musculoskeletal and visceral abnormalities. In the LSD, the abnormally diminished lysosomal enzyme results in accumulation of unmetabolized catabolites in distended lysosomes. Because of the subcellular morphology and size of lysosomes, electron microscopy is an ideal tool to study tissue from patients with suspected LSD. In patients with LSD all cells lack the specific lysosomal enzyme but the distribution of storage material is dependent on the extent of catabolism of the substrate in each cell type under normal circumstances. Lysosmal storages diseases affect many cell types and tissues. Storage material though does not accumulate in all tissues and cell types and may be different biochemically and morphologically in different tissues.Conjunctiva, skin, rectal mucosa and peripheral blood leukocytes may show ultrastructural evidence of lysosomal storage even in the absence of clinical findings and thus any of these tissues can be used for ultrastructural examination in the diagnostic evaluation of patients with suspected LSD. Biopsy of skin and conjunctiva are easily obtained and provide multiple cell types including endothelium, epithelium, fibroblasts and nerves for ultrastructural study. Fibroblasts from skin and conjunctiva can also be utilized for the initiation of tissue cultures for chemical assays. Brain biopsy has been largely replaced by biopsy of more readily obtained tissue and by biochemical assays. Such assays though may give equivical or nondiagnostic results and in some lysosomal storage diseases an enzyme defect has not yet been identified and diagnoses can be made only by ultrastructural examination.

scholarly journals Selective deletion of SHIP-1 in hematopoietic cells in mice leads to severe lung inflammation involving ILC2 cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xujun Ye ◽  
Fengrui Zhang ◽  
Li Zhou ◽  
Yadong Wei ◽  
Li Zhang ◽  
...  
Keyword(s):  
Lung Inflammation ◽  
Airway Remodeling ◽  
Pulmonary Inflammation ◽  
Hematopoietic Cells ◽  
Cell Lineage ◽  
Allergic Inflammation ◽  
Cell Types ◽  
Lymphoid Cells ◽  
Whole Body

AbstractSrc homology 2 domain–containing inositol 5-phosphatase 1 (SHIP-1) regulates the intracellular levels of phosphotidylinositol-3, 4, 5-trisphosphate, a phosphoinositide 3–kinase (PI3K) product. Emerging evidence suggests that the PI3K pathway is involved in allergic inflammation in the lung. Germline or induced whole-body deletion of SHIP-1 in mice led to spontaneous type 2-dominated pulmonary inflammation, demonstrating that SHIP-1 is essential for lung homeostasis. However, the mechanisms by which SHIP-1 regulates lung inflammation and the responsible cell types are still unclear. Deletion of SHIP-1 selectively in B cells, T cells, dendritic cells (DC) or macrophages did not lead to spontaneous allergic inflammation in mice, suggesting that innate immune cells, particularly group 2 innate lymphoid cells (ILC2 cells) may play an important role in this process. We tested this idea using mice with deletion of SHIP-1 in the hematopoietic cell lineage and examined the changes in ILC2 cells. Conditional deletion of SHIP-1 in hematopoietic cells in Tek-Cre/SHIP-1 mice resulted in spontaneous pulmonary inflammation with features of type 2 immune responses and airway remodeling like those seen in mice with global deletion of SHIP-1. Furthermore, when compared to wild-type control mice, Tek-Cre/SHIP-1 mice displayed a significant increase in the number of IL-5/IL-13 producing ILC2 cells in the lung at baseline and after stimulation by allergen Papain. These findings provide some hints that PI3K signaling may play a role in ILC2 cell development at baseline and in response to allergen stimulation. SHIP-1 is required for maintaining lung homeostasis potentially by restraining ILC2 cells and type 2 inflammation.

scholarly journals Stomatal Development in the Context of Epidermal Tissues

2021 ◽  
Author(s):  
Keiko U Torii
Keyword(s):  
Arabidopsis Thaliana ◽  
Molecular Genetic ◽  
Cell Lineage ◽  
Optimal Growth ◽  
Cell Types ◽  
State Transitions ◽  
Stomatal Development ◽  
Water Control ◽  
Pavement Cells ◽  
The Core

Abstract Background Stomata are adjustable pores on the surface of plant shoots for efficient gas exchange and water control. The presence of stomata is essential for plant growth and survival, and the evolution of stomata is considered as a key developmental innovation of the land plants, allowing colonization on land from aquatic environments some 450 million years ago. In the past two decades, molecular genetic studies using the model plant Arabidopsis thaliana identified key genes and signalling modules that regulate stomatal development: master-regulatory transcription factors that orchestrate cell-state transitions and peptide-receptor signal transduction pathways, which, together, enforce proper patterning of stomata within the epidermis. Studies in diverse plant species, ranging from bryophytes to angiosperm grasses, have begun to unravel the conservation and uniqueness of the core modules in stomatal development. Scope Here, I review the mechanisms of stomatal development in the context of epidermal tissue patterning. First, I introduce the core regulatory mechanisms of stomatal patterning and differentiation in the model species Arabidopsis thaliana. Subsequently, experimental evidence is presented supporting the idea that different cell types within the leaf epidermis, namely stomata, hydathodes pores, pavement cells, and trichomes, either share developmental origins or mutually influence each other’s gene regulatory circuits during development. Emphasis is taken on extrinsic and intrinsic signals regulating the balance between stomata and pavement cells, specifically by controlling the fate of Stomatal-Lineage Ground Cells (SLGCs) to remain within the stomatal-cell lineage or differentiate into pavement cells. Finally, I discuss the influence of inter-tissue-layer communication between the epidermis and underlying mesophyll/vascular tissues on stomatal differentiation. Understanding the dynamic behaviors of stomatal precursor cells and their differentiation in the broader context of tissue and organ development may help design plants tailored for optimal growth and productivity in specific agricultural applications and a changing environment.

scholarly journals Synthesis and Evaluation of AlgNa-g-poly(QCL-co-HEMA) Hydrogels as Platform for Chondrocyte Proliferation and Controlled Release of Betamethasone

2021 ◽  
Vol 22 (11) ◽  
pp. 5730
Author(s):  
Jomarien García-Couce ◽  
Marioly Vernhes ◽  
Nancy Bada ◽  
Lissette Agüero ◽  
Oscar Valdés ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Controlled Release ◽  
Biomedical Applications ◽  
Release Kinetics ◽  
Cell Types ◽  
Tissue Engineering Scaffolds ◽  
Almost All ◽  
Scanning Electron

Hydrogels obtained from combining different polymers are an interesting strategy for developing controlled release system platforms and tissue engineering scaffolds. In this study, the applicability of sodium alginate-g-(QCL-co-HEMA) hydrogels for these biomedical applications was evaluated. Hydrogels were synthesized by free-radical polymerization using a different concentration of the components. The hydrogels were characterized by Fourier transform-infrared spectroscopy, scanning electron microscopy, and a swelling degree. Betamethasone release as well as the in vitro cytocompatibility with chondrocytes and fibroblast cells were also evaluated. Scanning electron microscopy confirmed the porous surface morphology of the hydrogels in all cases. The swelling percent was determined at a different pH and was observed to be pH-sensitive. The controlled release behavior of betamethasone from the matrices was investigated in PBS media (pH = 7.4) and the drug was released in a controlled manner for up to 8 h. Human chondrocytes and fibroblasts were cultured on the hydrogels. The MTS assay showed that almost all hydrogels are cytocompatibles and an increase of proliferation in both cell types after one week of incubation was observed by the Live/Dead® assay. These results demonstrate that these hydrogels are attractive materials for pharmaceutical and biomedical applications due to their characteristics, their release kinetics, and biocompatibility.

scholarly journals ELECTRON MICROSCOPY OF THE NUCLEAR MEMBRANE OF AMOEBA PROTEUS

1956 ◽  
Vol 2 (4) ◽  
pp. 445-448 ◽  
Author(s):  
Marie H. Greider ◽  
Wencel J. Kostir ◽  
Walter J. Frajola
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Nuclear Membrane ◽  
Outer Layer ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Cell Types ◽  
Amoeba Proteus ◽  
Nuclear Membranes ◽  
Thin Sectioning

An electron microscope study of the nuclear membrane of Amoeba proteus by thin sectioning techniques has revealed an ultrastructure in the outer layer of the membrane that is homologous to the pores and annuli observed in the nuclear membranes of many other cell types studied by these techniques. An inner honeycombed layer apparently unique to Amoeba proteus is also described.

scholarly journals Site Specific Three-dimensional Structural Analysis in Tissues and Cells Using Automated DualBeam Slice &View

2007 ◽  
Vol 15 (2) ◽  
pp. 26-31 ◽  
Author(s):  
Ben Lich
Keyword(s):  
Electron Microscopy ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Surface Region ◽  
Dimensional Structure ◽  
Near Surface ◽  
Imaging Capability ◽  
Fluorescent Markers ◽  
Confocal And Electron Microscopy

DualBeam instruments that combine the imaging capability of scanning electron microscopy (SEM) with the cutting and deposition capability of a focused ion beam (FIB) provide biologists with a powerful tool for investigating three-dimensional structure with nanoscale (1 nm-100 nm) resolution. Ever since Van Leeuwenhoek used the first microscope to describe bacteria more than 300 years ago, microscopy has played a central role in scientists' efforts to understand biological systems. Light microscopy is generally limited to a useful resolution of about a micrometer. More recently the use of confocal and electron microscopy has enabled investigations at higher resolution. Used with fluorescent markers, confocal microscopy can detect and localize molecular scale features, but its imaging resolution is still limited. SEM is capable of nanometer resolution, but is limited to the near surface region of the sample.

scholarly journals Non-apoptotic enteroblast-specific role of the initiator caspase Dronc for development and homeostasis of the Drosophila intestine

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jillian L. Lindblad ◽  
Meghana Tare ◽  
Alla Amcheslavsky ◽  
Alicia Shields ◽  
Andreas Bergmann
Keyword(s):  
Normal Development ◽  
Cell Lineage ◽  
Cell Types ◽  
Specific Role ◽  
Mutant Phenotype ◽  
Apoptotic Pathway ◽  
Specific Expression ◽  
Card Domain

AbstractThe initiator caspase Dronc is the only CARD-domain containing caspase in Drosophila and is essential for apoptosis. Here, we report that homozygous dronc mutant adult animals are short-lived due to the presence of a poorly developed, defective and leaky intestine. Interestingly, this mutant phenotype can be significantly rescued by enteroblast-specific expression of dronc+ in dronc mutant animals, suggesting that proper Dronc function specifically in enteroblasts, one of four cell types in the intestine, is critical for normal development of the intestine. Furthermore, enteroblast-specific knockdown of dronc in adult intestines triggers hyperplasia and differentiation defects. These enteroblast-specific functions of Dronc do not require the apoptotic pathway and thus occur in a non-apoptotic manner. In summary, we demonstrate that an apoptotic initiator caspase has a very critical non-apoptotic function for normal development and for the control of the cell lineage in the adult midgut and therefore for proper physiology and homeostasis.

Abstract 313: Twist Contributes to Cardiomyocyte Renewal and is Required for Maintenance of Adult Cardiac Function

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Yi-Li Min ◽  
Svetlana Bezprozvannaya ◽  
Drazen Šošic ◽  
Young-Jae Nam ◽  
Hesham Sadek ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Cardiac Fibroblasts ◽  
Cell Lineage ◽  
Cardiac Regeneration ◽  
Cell Types ◽  
Bhlh Transcription Factor ◽  
Adult Heart ◽  
Twist 1 ◽  
Essential Contribution

Cardiomyocyte renewal occurs very slowly in adult mammals, and little is known of the genetic basis of cardiac regeneration. Twist is a highly conserved bHLH transcription factor responsible for Drosophila mesoderm formation during embryogenesis. Recent studies have shown that Twist protein is essential for muscle regeneration in adult Drosophila, but the potential role of Twist in the mammalian heart has not been explored. There are two Twist genes in vertebrates, Twist-1 and -2. We show that Twist-1 and -2 are expressed in epicardium and interstitial cells but not in differentiated cardiomyocytes in mice. To understand the potential function of Twist-dependent lineages in the adult heart, we generated inducible Twist2CreERT2; ROSA26-tdTomato reporter mice. By treating these mice with tamoxifen at 8 weeks of age, we observed progressive labeling of various cell types, such as epithelial cells, cardiac fibroblasts, and cardiomyocytes in the heart. We isolated Tomato-positive nonmyocytes from these mice and found that these cells can differentiate into cardiomyocytes and other cell types in vitro. Furthermore, cardiac-specific deletion of both Twist1 and Twist2 resulted in an age-dependent lethal cardiomyopathy. These findings reveal an essential contribution of Twist to long-term maintenance of cardiac function and support the concept of slow, lifelong renewal of cardiomyocytes from a Twist-dependent cell lineage in the adult heart.

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