scholarly journals SEM Analyses of Fossilized Chondrocytes in the Extinct Birds Yanornis and Confuciusornis: Insights on Taphonomy and Modes of Preservation in the Jehol Biota

2021 ◽  
Vol 9 ◽  
Author(s):  
Alida M. Bailleul ◽  
Zhonghe Zhou
Keyword(s):  
Soft Tissues ◽  
Carbonaceous Material ◽  
Cell Types ◽  
Sem Analysis ◽  
Common Mechanism ◽  
Cell Nuclei ◽  
Jehol Biota ◽  
Calcified Cartilage ◽  
Spherical Cells

Calcified cartilage is a vertebrate tissue that has unique characteristics, such as a high percentage of calcification, avascularity and cells with apparently delayed autolytic processes after death. All of these factors suggest that fossilized cartilage may be favorable to exceptional cellular preservation, but little is known about chondrocyte fossilization overall in vertebrate paleontology. To further understand the spectrum of cellular preservation in this tissue, we analyze the morphology and the chemistry of some intralacunar content seen in previously published avian cartilage from the Early Cretaceous Jehol biota (in Yanornis and Confuciusornis). For this, we combine standard paleohistology with Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). To better identify some fossilized structures, we compare them with experimentally decayed and biofilm-invaded avian cartilage. Histological images of the cartilage of Yanornis show structures that resemble cell nuclei within chondrocyte lacunae. An SEM analysis on this cartilage shows that some lacunae are filled with a type of in vivo mineralization (similar to micropetrotic lacunae) and others are filled with small and spherical silicified cells surrounded by an amorphous carbonaceous material. These silicified cells apparently underwent postmortem cell shrinkage and do not constitute cell nuclei. Confuciusornis shows filamentous, non-spherical cells that are mostly made of silicon and carbon. This cell morphology does not resemble that of typical healthy chondrocytes, but based on comparison with decaying, biofilm-infiltrated chondrocyte lacunae from extant material, the most plausible conclusion is that the cells of Confuciusornis were partially autolyzed prior to their mineralization. In Yanornis and Confuciusornis respectively, silicification and alumino-silicification were responsible for chondrocyte preservation; while alumino-silicification and ironization occurred in their soft tissues. This shows that alumino-silicification is quite a common mechanism of cellular and soft-tissue preservation in the Jehol biota. Moreover, the two different chondrocyte morphologies (spherical and filamentous) apparently reflect two taphonomical histories, including different timings of postmortem permineralization (one rapid and one much more delayed). This type of analysis paired with more actuotaphonomy experiments will be needed in the future to better understand the preservation potential of chondrocytes and other cell types in the fossil record.

In vivo expression patterns of MyoD, p21, and Rb proteins in myonuclei and satellite cells of denervated rat skeletal muscle

2004 ◽  
Vol 287 (2) ◽  
pp. C484-C493 ◽  
Author(s):  
Minenori Ishido ◽  
Katsuya Kami ◽  
Mitsuhiko Masuhara
Keyword(s):  
Skeletal Muscle ◽  
Satellite Cell ◽  
Time Course ◽  
Kinase Inhibitor ◽  
Expression Patterns ◽  
Cell Types ◽  
Cell Nuclei ◽  
Myogenic Regulatory Factor

MyoD, a myogenic regulatory factor, is rapidly expressed in adult skeletal muscles in response to denervation. However, the function(s) of MyoD expressed in denervated muscle has not been adequately elucidated. In vitro, it directly transactivates cyclin-dependent kinase inhibitor p21 (p21) and retinoblastoma protein (Rb), a downstream target of p21. These factors then act to regulate cell cycle withdrawal and antiapoptotic cell death. Using immunohistochemical approaches, we characterized cell types expressing MyoD, p21, and Rb and the relationship among these factors in the myonucleus of denervated muscles. In addition, we quantitatively examined the time course changes and expression patterns among distinct myofiber types of MyoD, p21, and Rb during denervation. Denervation induced MyoD expression in myonuclei and satellite cell nuclei, whereas p21 and Rb were found only in myonuclei. Furthermore, coexpression of MyoD, p21, and Rb was induced in the myonucleus, and quantitative analysis of these factors determined that there was no difference among the three myofiber types. These observations suggest that MyoD may function in myonuclei in response to denervation to protect against denervation-induced apoptosis via perhaps the activation of p21 and Rb, and function of MyoD expressed in satellite cell nuclei may be negatively regulated. The present study provides a molecular basis to further understand the function of MyoD expressed in the myonuclei and satellite cell nuclei of denervated skeletal muscle.

scholarly journals Regenerative Models for the Integration and Regeneration of Head Skeletal Tissues

2018 ◽  
Vol 19 (12) ◽  
pp. 3752 ◽  
Author(s):  
Warren Vieira ◽  
Catherine McCusker
Keyword(s):  
Soft Tissues ◽  
Treatment Options ◽  
Positional Information ◽  
Cell Types ◽  
Model Organisms ◽  
Biological Targets ◽  
Tissue Integration ◽  
Repair Mechanisms

Disease of, or trauma to, the human jaw account for thousands of reconstructive surgeries performed every year. One of the most popular and successful treatment options in this context involves the transplantation of bone tissue from a different anatomical region into the affected jaw. Although, this method has been largely successful, the integration of the new bone into the existing bone is often imperfect, and the integration of the host soft tissues with the transplanted bone can be inconsistent, resulting in impaired function. Unlike humans, several vertebrate species, including fish and amphibians, demonstrate remarkable regenerative capabilities in response to jaw injury. Therefore, with the objective of identifying biological targets to promote and engineer improved outcomes in the context of jaw reconstructive surgery, we explore, compare and contrast the natural mechanisms of endogenous jaw and limb repair and regeneration in regenerative model organisms. We focus on the role of different cell types as they contribute to the regenerating structure; how mature cells acquire plasticity in vivo; the role of positional information in pattern formation and tissue integration, and limitations to endogenous regenerative and repair mechanisms.

scholarly journals Influence of Nano, Micro and Macro Topography of Dental Implant Surfaces on Human Gingival Fibroblasts

2021 ◽  
Vol 22 (18) ◽  
pp. 9871
Author(s):  
Morena Petrini ◽  
Tania Vanessa Pierfelice ◽  
Emira D’Amico ◽  
Natalia Di Pietro ◽  
Assunta Pandolfi ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Titanium Implant ◽  
Sem Analysis ◽  
Human Gingival Fibroblasts ◽  
Dependent Manner ◽  
Gingival Fibroblasts ◽  
Force Microscopy ◽  
Atomic Force

Current research on dental implants has mainly focused on the influence of surface roughness on the rate of osseointegration, while studies on the development of surfaces to also improve the interaction of peri-implant soft tissues are lacking. To this end, the first purpose of this study was to evaluate the response of human gingival fibroblasts (hGDFs) to titanium implant discs (Implacil De Bortoli, Brazil) having different micro and nano-topography: machined (Ti-M) versus sandblasted/double-etched (Ti-S). The secondary aim was to investigate the effect of the macrogeometry of the discs on cells: linear-like (Ti-L) versus wave-like (Ti-W) surfaces. The atomic force microscopy (AFM) and scanning electron microscopy (SEM) analysis showed that the Ti-S surfaces were characterized by a significantly higher micro and nano roughness and showed the 3D macrotopography of Ti-L and Ti-W surfaces. For in vitro analyses, the hGDFs were seeded into titanium discs and analyzed at 1, 3, and 5 days for adhesion and morphology (SEM) viability and proliferation (Cck-8 and MTT assays). The results showed that all tested surfaces were not cytotoxic for the hGDFs, rather the nano-micro and macro topography favored their proliferation in a time-dependent manner. Especially, at 3 and 5 days, the number of cells on Ti-L was higher than on other surfaces, including Ti-W surfaces. In conclusion, although further studies are needed, our in vitro data proved that the use of implant discs with Ti-S surfaces promotes the adhesion and proliferation of gingival fibroblasts, suggesting their use for in vivo applications.

scholarly journals NaNuTrap, a technique for in vivo cell nucleus labelling using nanobodies

Development ◽  
2021 ◽  
Author(s):  
Zsuzsa Ákos ◽  
Leslie Dunipace ◽  
Angelike Stathopoulos
Keyword(s):  
Fluorescent Proteins ◽  
Cell Types ◽  
Cell Counting ◽  
Cell Labelling ◽  
Cell Nuclei ◽  
Maturation Time ◽  
Developmental Processes ◽  
Fluorescent Signal ◽  
Two Photon

In vivo cell labelling is challenging in fast developmental processes because many cell types differentiate more quickly than the maturation time of fluorescent proteins making visualization of these tissues impossible with standard techniques. Here we present a nanobody-based method, Nanobody Nuclear Trap (NaNuTrap), which works with the existing Gal4/UAS system in Drosophila and allows for early in vivo cell nuclei labelling independent of the fluorescent protein's maturation time. This restores the utility of fluorescent proteins that have longer maturation times, such as those used in two-photon imaging, for live imaging of fast or very early developmental processes. We also present a more general application of this system, whereby NaNuTrap can convert cytoplasmic GFP expressed in any existing transgenic fly line into a nuclear label. This nuclear re-localization of the fluorescent signal can improve the utility of the GFP label, for example in cell counting, as well as resulting in a general increase in intensity of the live fluorescent signal. We demonstrate these capabilities of NaNuTrap by effectively tracking subsets of cells during the fast movements associated with gastrulation.

scholarly journals Pathogenesis of medication-related osteonecrosis of the jaw: a comparative study of in vivo and in vitro trials

2018 ◽  
Vol 46 (10) ◽  
pp. 4277-4296 ◽  
Author(s):  
Henrik Holtmann ◽  
Julian Lommen ◽  
Norbert R. Kübler ◽  
Christoph Sproll ◽  
Majeed Rana ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Umbilical Vein ◽  
Cell Types ◽  
Osteonecrosis Of The Jaw ◽  
In Vitro Studies ◽  
Cochrane Library ◽  
Close Relationship ◽  
Umbilical Vein Endothelial Cells

Objective This study was performed to determine whether the results of prevailing in vivo and in vitro studies offer a reliable model for investigation of medication-related osteonecrosis of the jaw (MRONJ). Methods Embase, Medline, and the Cochrane Library were searched for articles published from September 2003 to June 2017 involving experimental approaches to the pathogenesis of MRONJ. In vivo and in vitro trials were analyzed with respect to the scientific question, study design, methodology, and results. Results Of 139 studies, 87, 46, and 6 conducted in vivo, in vitro, and both in vivo and in vitro experiments, respectively. Rats, mice, dogs, minipigs, sheep, and rabbits were the preferred animal models used. Osteoblasts, osteoclasts, fibroblasts, keratinocytes, macrophages, and human umbilical vein endothelial cells were the preferred cell types. Zoledronate, alendronate, ibandronate, and risedronate were the most frequent bisphosphonates used. MRONJ was most reliably induced in minipigs because of the close relationship with human bone physiology. In vitro studies showed that reduced viability, growth, and migration of cells in the bone and soft tissues were causative for MRONJ. Other than exposed jawbone after tooth extraction, no reliable cofactors were found. Conclusion The minipig is the most suitable animal model for MRONJ.

SEM analysis of fish scale cross sections: A technique study

1992 ◽  
Vol 50 (1) ◽  
pp. 744-745
Author(s):  
M.E. Lee ◽  
A. Moller ◽  
P.S.O. Fouche ◽  
I.G Gaigher
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cross Sections ◽  
Soft Tissues ◽  
Close Association ◽  
Sem Analysis ◽  
Fish Scale ◽  
Fish Scales ◽  
Micro Structures ◽  
Scanning Electron

Scanning electron microscopy of fish scales has facilitated the application of micro-structures to systematics. Electron microscopy studies have added more information on the structure of the scale and the associated cells, many problems still remain unsolved, because of our incomplete knowledge of the process of calcification. One of the main purposes of these studies has been to study the histology, histochemistry, and ultrastructure of both calcified and decalcified scales, and associated cells, and to obtain more information on the mechanism of calcification in the scales. The study of a calcified scale with the electron microscope is complicated by the difficulty in sectioning this material because of the close association of very hard tissue with very soft tissues. Sections often shatter and blemishes are difficult to avoid. Therefore the aim of this study is firstly to develop techniques for the preparation of cross sections of fish scales for scanning electron microscopy and secondly the application of these techniques for the determination of the structures and calcification of fish scales.

Ultrastructural Study of a differentiating human colon carcinoma cell line

1990 ◽  
Vol 48 (3) ◽  
pp. 208-209
Author(s):  
Sylvie Polak-Charcon ◽  
Mehrdad Hekmati ◽  
Yehuda Ben Shaul
Keyword(s):  
Cell Line ◽  
Morphological Changes ◽  
Secretory Granules ◽  
Human Colon ◽  
Cell Types ◽  
Culture Conditions ◽  
Morphological Evidence ◽  
Human Colon Carcinoma Cell ◽  
Colon Cell

The epithelium of normal human colon mucosa “in vivo” exhibits a gradual pattern of differentiation as undifferentiated stem cells from the base of the crypt of “lieberkuhn” rapidly divide, differentiate and migrate toward the free surface. The major differentiated cell type of the intestine observed are: absorptive cells displaying brush border, goblet cells containing mucous granules, Paneth and endocrine cells containing dense secretory granules. These different cell types are also found in the intestine of the 13-14 week old embryo.We present here morphological evidence showing that HT29, an adenocarcinoma of the human colon cell line, can differentiate into various cell types by changing the growth and culture conditions and mimic morphological changes found during development of the intestine in the human embryo.HT29 cells grown in tissue-culture dishes in DMEM and 10% FCS form at late confluence a multilayer of morphologically undifferentiated cell culture covered with irregular microvilli, and devoid of tight junctions (Figs 1-3).

Ultrastructural observations on the in vitro cytoadherence of Plasmodium falciparum infected red blood cells

1990 ◽  
Vol 48 (3) ◽  
pp. 914-915
Author(s):  
D.J.P. Ferguson ◽  
A.R. Berendt ◽  
J. Tansey ◽  
K. Marsh ◽  
C.I. Newbold
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Umbilical Vein ◽  
Cell Types ◽  
Amelanotic Melanoma ◽  
Cytoplasmic Process ◽  
Umbilical Vein Endothelial Cells

In human malaria, the most serious clinical manifestation is cerebral malaria (CM) due to infection with Plasmodium falciparum. The pathology of CM is thought to relate to the fact that red blood cells containing mature forms of the parasite (PRBC) cytoadhere or sequester to post capillary venules of various tissues including the brain. This in vivo phenomenon has been studied in vitro by examining the cytoadherence of PRBCs to various cell types and purified proteins. To date, three Ijiost receptor molecules have been identified; CD36, ICAM-1 and thrombospondin. The specific changes in the PRBC membrane which mediate cytoadherence are less well understood, but they include the sub-membranous deposition of electron-dense material resulting in surface deformations called knobs. Knobs were thought to be essential for cytoadherence, lput recent work has shown that certain knob-negative (K-) lines can cytoadhere. In the present study, we have used electron microscopy to re-examine the interactions between K+ PRBCs and both C32 amelanotic melanoma cells and human umbilical vein endothelial cells (HUVEC).We confirm previous data demonstrating that C32 cells possess numerous microvilli which adhere to the PRBC, mainly via the knobs (Fig. 1). In contrast, the HUVEC were relatively smooth and the PRBCs appeared partially flattened onto the cell surface (Fig. 2). Furthermore, many of the PRBCs exhibited an invagination of the limiting membrane in the attachment zone, often containing a cytoplasmic process from the endothelial cell (Fig. 2).

Biological and biomedical applications of collagenous biomaterials

1990 ◽  
Vol 48 (3) ◽  
pp. 856-857
Author(s):  
Yasushi P. Kato ◽  
Michael G. Dunn ◽  
Frederick H. Silver ◽  
Arthur J. Wasserman
Keyword(s):  
Biomedical Applications ◽  
Soft Tissues ◽  
Collagen Fibers ◽  
Bone Collagen ◽  
Cover Slip ◽  
Fibroblast Migration ◽  
Cellular Expression ◽  
Defect Repair

Collagenous biomaterials have been used for growing cells in vitro as well as for augmentation and replacement of hard and soft tissues. The substratum used for culturing cells is implicated in the modulation of phenotypic cellular expression, cellular orientation and adhesion. Collagen may have a strong influence on these cellular parameters when used as a substrate in vitro. Clinically, collagen has many applications to wound healing including, skin and bone substitution, tendon, ligament, and nerve replacement. In this report we demonstrate two uses of collagen. First as a fiber to support fibroblast growth in vitro, and second as a demineralized bone/collagen sponge for radial bone defect repair in vivo.For the in vitro study, collagen fibers were prepared as described previously. Primary rat tendon fibroblasts (1° RTF) were isolated and cultured for 5 days on 1 X 15 mm sterile cover slips. Six to seven collagen fibers, were glued parallel to each other onto a circular cover slip (D=18mm) and the 1 X 15mm cover slip populated with 1° RTF was placed at the center perpendicular to the collagen fibers. Fibroblast migration from the 1 x 15mm cover slip onto and along the collagen fibers was measured daily using a phase contrast microscope (Olympus CK-2) with a calibrated eyepiece. Migratory rates for fibroblasts were determined from 36 fibers over 4 days.

A Comparative Study of the in vivo Distribution of 32P-Polyphosphates and 32P-Orthophosphate

1972 ◽  
Vol 11 (01) ◽  
pp. 70-78
Author(s):  
Esther Miller ◽  
Leopoldo Anghileri
Keyword(s):  
Radiation Dose ◽  
Comparative Study ◽  
Soft Tissues ◽  
Tumor Bearing ◽  
In Vivo Distribution ◽  
The Cross ◽  
Total Body

SummaryThe distribution of 32P-polyphosphates (lineal and cross-linked) and 32Porthophosphate in normal and tumor bearing animals has been studied. Differences between the cross-linked and the lineal form are related to a different degree of susceptibility to the hydrolysis by the phosphatases. In contrast to orthophosphate, the polyphosphates showed a lower accumulation in soft tissues which gives an advantageous reduction of the total body radiation dose.

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