scholarly journals Avalanches During Epithelial Tissue Growth; Uniform Growth and a Drosophila Eye Disc Model

2021 ◽  
Author(s):  
George Courcoubetis ◽  
Chi Xu ◽  
Sergey Nuzhdin ◽  
Stephan Haas
Keyword(s):  
Amorphous Materials ◽  
Cell Movement ◽  
Growth Dynamics ◽  
Tissue Growth ◽  
Epithelial Tissue ◽  
Apical Constriction ◽  
Tension Distribution ◽  
The Third ◽  
Eye Disc

AbstractIn the physicists’ perspective, epithelial tissues constitute an exotic type of active matter with non-linear properties reminiscent of amorphous materials. In the context of a circular proliferating epithelium, modeled by the quasistatic vertex model, we identify novel discrete tissue scale rearrangements, i.e. cellular flow avalanches, which are a form of collective cell movement. During the avalanches, the cellular trajectories are radial in the periphery and form a vortex in the core. After the onset of these avalanches, the epithelial area grows discontinuously. The avalanches are found to be stochastic, and their strength is determined by the density of cells in the tissue. Overall, avalanches regularize the spatial tension distribution along tissue. Furthermore, the avalanche distribution is found to obey a power law, with an exponent consistent with sheer induced avalanches in amorphous materials. To decipher the role of avalanches in organ development, we simulate epithelial growth of theDrosophilaeye disc during the third instar using a computational model, which includes both signaling and mechanistic signalling. During the third instar, the morphogenetic furrow (MF), a ∼10 cell wide wave of apical area constriction propagates through the epithelium, making it a system with interesting mechanical properties. These simulations are used to understand the details of the growth process, the effect of the MF on the growth dynamics on the tissue scale, and to make predictions. The avalanches are found to depend on the strength of the apical constriction of cells in the MF, with stronger apical constriction leading to less frequent and more pronounced avalanches. The results herein highlight the dependence of simulated tissue growth dynamics on relaxation timescales, and serve as a guide forin vitroexperiments.

Effect of exogenous bovine growth hormone and ovariectomy on prepubertal mammary growth, serum hormones and acute in-vitro proliferative response of mammary explants from Holstein heifers

1993 ◽  
Vol 139 (1) ◽  
pp. 19-26 ◽  
Author(s):  
S. Purup ◽  
K. Sejrsen ◽  
J. Foldager ◽  
R. M. Akers
Keyword(s):  
Mammary Gland ◽  
Growth Response ◽  
Mammary Development ◽  
Tissue Growth ◽  
Epithelial Tissue ◽  
Holstein Friesian ◽  
Serum Hormone ◽  
Term Administration

ABSTRACT Sixteen prepubertal Holstein Friesian heifers were used to study the effect of long-term administration of bovine GH (bGH) on mammary development in intact and ovariectomized heifers. Eight heifers were ovariectomized at 2·5 months of age. Four intact and four ovariectomized heifers received subcutaneous injection of bGH (15 mg/day) for 15 weeks starting at 176 ± 3 days of age (147 ± 3 kg body weight), while the remaining eight heifers received an equal volume of excipient. Blood samples were collected weekly from 2 months of age. Heifers were slaughtered on the day after the last injection of bGH or excipient. Mammary gland development was quantified by dissection, chemical analysis and computer tomographic scanning. Mammary growth response at the time of slaughter was examined in cultures with explants prepared from parenchyma. Histological and histoautoradiographic studies with explants were performed. Treatment with bGH resulted in a significantly (P<0·05) smaller mammary gland because of a reduced amount of extraparenchymal tissue. Ovariectomy markedly reduced the amount of parenchymal tissue. Growth response in mammary explants showed no treatment differences, suggesting that the decreased amount of parenchyma in ovariectomized heifers was caused by a decrease in mammary cell proliferation occurring some time prior to slaughter. The histological composition of mammary parenchyma was not changed by bGH treatment. However, ovariectomy resulted in less epithelial tissue (P<0·001) and lumen (P<0·05) and more stroma (P< 0·001), expressed as percentage tissue area. Serum hormone concentrations of bGH and insulin-like growth factor-I (IGF-I) were increased by bGH treatment in both intact and ovariectomized heifers. However, despite the fact that mammary growth in ovariectomized heifers was eradicated, the serum concentration of oestradiol was only decreased by one-third compared with intact heifers. The study therefore confirms the importance of ovarian secretions for mammary growth and development in prepubertal heifers. However, the results give no clear evidence of an interaction between ovarian secretions and GH on the regulation of the development of the mammary parenchyma in heifers. Journal of Endocrinology (1993) 139, 19–26

Correlated Studies of Cellular Interactions Using TEM, Freeze Etching, and SEM

1974 ◽  
Vol 32 ◽  
pp. 320-321
Author(s):  
J. P. Revel
Keyword(s):  
Developmental Stages ◽  
Three Dimensional ◽  
Cell Movement ◽  
Cellular Interactions ◽  
Serial Sections ◽  
Cell Sheets ◽  
Freeze Etching ◽  
Early Developmental

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.

Increased Protein Synthesis by Human Platelets during Phagocytosis of Latex Particles in Vitro

1976 ◽  
Vol 35 (02) ◽  
pp. 350-357 ◽  
Author(s):  
Hana Bessler ◽  
Galila Agam ◽  
Meir Djaldetti
Keyword(s):  
Protein Synthesis ◽  
Fold Increase ◽  
Human Platelets ◽  
Polystyrene Latex ◽  
Latex Particles ◽  
The Third ◽  
Platelet Protein ◽  
Dose Dependent ◽  
Phagocytotic Activity

SummaryA three-fold increase of protein synthesis by human platelets during in vitro phagocytosis of polystyrene latex particles was detected. During the first two hours of incubation, the percentage of phagocytizing platelets and the number of latex particles per platelet increased; by the end of the third hour, the first parameter remained stable, while the number of latex particles per cell had decreased.Vincristine (20 μg/ml of cell suspension) inhibited platelet protein synthesis. This effect was both time- and dose-dependent. The drug also caused a decrease in the number of phagocytizing cells, as well as in their phagocytotic activity.

Studies on Thrombolysis with Streptokinase

1971 ◽  
Vol 25 (02) ◽  
pp. 354-378 ◽  
Author(s):  
R Gottlob ◽  
L Stockinger ◽  
U Pötting ◽  
G Schattenmann
Keyword(s):  
Electron Microscopy ◽  
Cross Section ◽  
Whole Blood ◽  
Jugular Vein ◽  
Thin Sections ◽  
The Third ◽  
Morphological Findings ◽  
Blood Clots ◽  
Arteries And Veins

SummaryIn vitro whole blood clots of various ages, experimental thrombi produced in the jugular vein of rabbits and human thrombi from arteries and veins were examined in semi-thin sections and by means of electron microscopy.In all types of clots examined a typical course of retraction was found. Retraction starts with a dense excentrical focus which grows into a densification ring. After 24 hours the entire clot becomes almost homogeneously dense; later a secondary swelling sets in.Shortly after coagulation the erythrocytes on the rim of the clot are bi-concave discs. They then assume the shape of crenate spheres, turn into smooth spheres and finally become indented ghosts which have lost the largest part of their contents. In the inner zone, which makes up the bulk of the clot, we observed bi-concave discs prior to retraction. After retraction we see no crenations but irregularly shaped erythrocytes. Once the secondary swelling sets in, the cross-section becomes polygonal and later spherical. After extensive hemolysis we observe the “retiform thrombus” made up of ghosts.Experimental and clinical thrombi present the same morphology but are differentiated from in vitro clots by: earlier hemolysis, immigration of leukocytes, formation of a rim layer consisting of fibrin and thrombocytes, and the symptoms of organization. Such symptoms of organization which definitely will prevent lysis with streptokinase were found relatively late in experimental and clinical thrombi. Capillary buds and capillary loops were never found in clinical thrombi prior to the third month.The morphological findings agree with earlier physical and enzymatic investigations. The observation that phenomena of reorganization occur relatively late and frequently only in the rim areas of large thrombi explains why lytic therapy is possible in some of the chronic obliterations.

scholarly journals Influence of icariin on inflammation, apoptosis, invasion, and tumor immunity in cervical cancer by reducing the TLR4/MyD88/NF-κB and Wnt/β-catenin pathways

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chunyang Li ◽  
Shuangqing Yang ◽  
Huaqing Ma ◽  
Mengjia Ruan ◽  
Luyan Fang ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Underlying Mechanism ◽  
Tissue Growth ◽  
Migration And Invasion ◽  
Dependent Manner ◽  
Antitumor Effects ◽  
Siha Cells ◽  
Cervical Cancer Cells

Abstract Background Cervical cancer is a type of the most common gynecology tumor in women of the whole world. Accumulating data have shown that icariin (ICA), a natural compound, has anti-cancer activity in different cancers, including cervical cancer. The study aimed to reveal the antitumor effects and the possible underlying mechanism of ICA in U14 tumor-bearing mice and SiHa cells. Methods The antitumor effects of ICA were investigated in vivo and in vitro. The expression of TLR4/MyD88/NF-κB and Wnt/β-catenin signaling pathways were evaluated. Results We found that ICA significantly suppressed tumor tissue growth and SiHa cells viability in a dose-dependent manner. Also, ICA enhanced the anti-tumor humoral immunity in vivo. Moreover, ICA significantly improved the composition of the microbiota in mice models. Additionally, the results clarified that ICA significantly inhibited the migration, invasion capacity, and expression levels of TGF-β1, TNF-α, IL-6, IL-17A, IL-10 in SiHa cells. Meanwhile, ICA was revealed to promote the apoptosis of cervical cancer cells by down-regulating Ki67, survivin, Bcl-2, c-Myc, and up-regulating P16, P53, Bax levels in vivo and in vitro. For the part of mechanism exploration, we showed that ICA inhibits the inflammation, proliferation, migration, and invasion, as well as promotes apoptosis and immunity in cervical cancer through impairment of TLR4/MyD88/NF-κB and Wnt/β-catenin pathways. Conclusions Taken together, ICA could be a potential supplementary agent for cervical cancer treatment.

scholarly journals The Bone Regeneration Capacity of BMP-2 + MMP-10 Loaded Scaffolds Depends on the Tissue Status

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 979
Author(s):  
Patricia Garcia-Garcia ◽  
Ricardo Reyes ◽  
José Antonio Rodriguez ◽  
Tomas Martín ◽  
Carmen Evora ◽  
...  
Keyword(s):  
Bone Formation ◽  
Bone Regeneration ◽  
Growth Promotion ◽  
Tissue Growth ◽  
Bone Morphogenetic Protein 2 ◽  
Morphogenetic Protein ◽  
Therapeutic Molecules ◽  
Positive Effect

Biomaterials-mediated bone formation in osteoporosis (OP) is challenging as it requires tissue growth promotion and adequate mineralization. Based on our previous findings, the development of scaffolds combining bone morphogenetic protein 2 (BMP-2) and matrix metalloproteinase 10 (MMP-10) shows promise for OP management. To test our hypothesis, scaffolds containing BMP-2 + MMP-10 at variable ratios or BMP-2 + Alendronate (ALD) were prepared. Systems were characterized and tested in vitro on healthy and OP mesenchymal stem cells and in vivo bone formation was studied on healthy and OP animals. Therapeutic molecules were efficiently encapsulated into PLGA microspheres and embedded into chitosan foams. The use of PLGA (poly(lactic-co-glycolic acid)) microspheres as therapeutic molecule reservoirs allowed them to achieve an in vitro and in vivo controlled release. A beneficial effect on the alkaline phosphatase activity of non-OP cells was observed for both combinations when compared with BMP-2 alone. This effect was not detected on OP cells where all treatments promoted a similar increase in ALP activity compared with control. The in vivo results indicated a positive effect of the BMP-2 + MMP-10 combination at both of the doses tested on tissue repair for OP mice while it had the opposite effect on non-OP animals. This fact can be explained by the scaffold’s slow-release rate and degradation that could be beneficial for delayed bone regeneration conditions but had the reverse effect on healthy animals. Therefore, the development of adequate scaffolds for bone regeneration requires consideration of the tissue catabolic/anabolic balance to obtain biomaterials with degradation/release behaviors suited for the existing tissue status.

A Summary of the Third Global Interferon-γ Release Assay Symposium

2013 ◽  
Vol 34 (6) ◽  
pp. 619-624 ◽  
Author(s):  
Antonino Catanzaro ◽  
Charles Daley
Keyword(s):  
Immune Response ◽  
Tuberculin Skin Test ◽  
Skin Test ◽  
Interferon Γ ◽  
Enzyme Linked Immunosorbent Assay ◽  
In Vitro Tests ◽  
The Third ◽  
Specific Antigens ◽  
Ifn Γ

Studies over the past several decades have dramatically increased our understanding of the immune response to Mycobacterium tuberculosis infection, and advances in proteomics and genomics have led to a new class of immune-diagnostic tests, termed interferon-γ (IFN-γ) release assays (IGRAs), which appear to obviate many of the problems encountered with the tuberculin skin test (TST). Worldwide, 2 IGRAs are currently commercially available. QuantiFERON-TB Gold In-Tube (Cellestis) is a third-generation product that uses an enzyme-linked immunosorbent assay to measure IFN-γ generated in whole blood stimulated with M. tuberculosis–specific antigens. T-Spot-TB (Oxford Immunotec) employs enzyme-linked immunosorbent spot technology to enumerate the number of purified lymphocytes that respond to M. tuberculosis–specific antigens by producing IFN-γ. These in vitro tests measure the host immune response to M. tuberculosis–specific antigens, which virtually eliminates false-positive cross reactions caused by bacillus Calmette-Guérin vaccination and/or exposure to environmental nontuberculous mycobacteria that plague the interpretation and accuracy of the tuberculin skin test (TST). The high specificity of IGRAs, together with sensitivity commensurate with or better than that of the TST, promises an accurate diagnosis and the ability to focus tuberculosis-control activities on those who are actually infected with M. tuberculosis. The Third Global Symposium was held over a 3-day period and was presented by the University of California, San Diego, Continuing Medical Education department; slides and sound recordings of each presentation are available at http://cme.ucsd.edu/igras/syllabus.html. A moderated discussion is also available at http://cme.ucsd.edu/igrasvideo. This document provides a summary of the key findings of the meeting, specifically focusing on the use of IGRAs in screening healthcare worker populations.

Combined Effects of Bone Marrow-Derived Mesenchymal Stem Cells and PLGA-PEG-PLGA Scaffolds on Repair of Articular Cartilage Defect

2013 ◽  
Vol 815 ◽  
pp. 345-349 ◽  
Author(s):  
Ching Wen Hsu ◽  
Ping Liu ◽  
Song Song Zhu ◽  
Feng Deng ◽  
Bi Zhang
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Articular Cartilage ◽  
Growth Factor ◽  
Cartilage Defect ◽  
Cartilage Regeneration ◽  
Tissue Growth ◽  
Cartilage Defects

Here we reported a combined technique for articular cartilage repair, consisting of bone arrow mesenchymal stem cells (BMMSCs) and poly (dl-lactide-co-glycolide-b-ethylene glycol-b-dl-lactide-co-glycolide) (PLGA-PEG-PLGA) triblock copolymers carried with tissue growth factor (TGF-belat1). In the present study, BMMSCs seeded on PLGA-PEG-PLGA with were incubated in vitro, carried or not TGF-belta1, Then the effects of the composite on repair of cartilage defect were evaluated in rabbit knee joints in vivo. Full-thickness cartilage defects (diameter: 5 mm; depth: 3 mm) in the patellar groove were either left empty (n=18), implanted with BMMSCs/PLGA (n=18), TGF-belta1 modified BMMSCs/PLGA-PEG-PLGA. The defect area was examined grossly, histologically at 6, 24 weeks postoperatively. After implantation, the BMMSCs /PLGA-PEG-PLGA with TGF-belta1 group showed successful hyaline-like cartilage regeneration similar to normal cartilage, which was superior to the other groups using gross examination, qualitative and quantitative histology. These findings suggested that a combination of BMMSCs/PLGA-PEG-PLGA carried with tissue growth factor (TGF-belat1) may be an alternative treatment for large osteochondral defects in high loading sites.

In vitro and in vivo pathologic effects of Vibrio parahaemolyticus on human epithelial cells

1984 ◽  
Vol 30 (3) ◽  
pp. 381-388 ◽  
Author(s):  
B. R. Merrell ◽  
R. I. Walker ◽  
S. W. Joseph
Keyword(s):  
Epithelial Cells ◽  
Epithelial Tissue ◽  
Ileal Mucosa ◽  
Cytotoxic Factor ◽  
Culture Cells ◽  
Vibrio Parahemolyticus ◽  
Buccal Epithelial Cells ◽  
Culture Supernate

The initial interaction and adherence of Vibrio parahemolyticus to epithelial tissue culture cells, human buccal epithelial cells, and the ileal mucosa of mice were studied. Using scanning electron microscopy, adherent bacteria were observed only on degenerating human embryonic intestinal, HeLa, and buccal cells; healthy normal cells were devoid of bacteria. Sheared V. parahaemolyticus, i.e., lacking flagella, did not adhere to either normal or degenerating tissue cells. Neither ultraviolet-inactivated organisms nor cell-free culture supernate affected the epithelial cells. Similar findings were observed on the mucosa of the ileum in mice inoculated with V. parahaemolyticus. It appears that V. parahaemolyticus possesses a cytotoxic factor which alters epithelial cells. This factor appears to be closely associated with viable organisms and may be a functional element in the adherence process of flagellated V. parahaemolyticus to mammalian epithelial cells.

The effect of catecholamines and catecholamine antagonists on the third larval moult of Dirofilaria immitis in vitro

1992 ◽  
Vol 66 (4) ◽  
pp. 273-278 ◽  
Author(s):  
E. V. Warbrick ◽  
S. A. Ward
Keyword(s):  
Dirofilaria Immitis ◽  
Parasitic Nematode ◽  
The Third ◽  
Adrenergic Antagonist ◽  
Third Stage ◽  
Larval Moult

ABSTRACTVarious catecholamines and catecholamine antagonists have been examined for their effects on the third larval moult of the parasitic nematode, Dirofilaria immitis, cultured in vitro. The non-selective α and β agonist, noradrenaline, and the β agonist, isoprenaline, had no effect on the timing of the third stage moult when used at a concentration of 10−5M. The α-adrenergic antagonist. phentolamine, resulted in worm mortality at 10−5M. At 10−7M, both phentolamine and the β-antagonist, propranolol caused a significant reduction in the numbers of larvae capable of completing the third stage moult. Idazoxan, an a2-antagonist, at 10−5M did not affect worm mortality but did completely prevent ecdysis. The potential of these compounds as possible filaricides is discussed.

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