The role of interstitial collagens in cleft formation of mouse embryonic submandibular gland during initial branching

Development ◽  
1988 ◽  
Vol 103 (2) ◽  
pp. 259-267 ◽  
Author(s):  
Y. Fukuda ◽  
Y. Masuda ◽  
J. Kishi ◽  
Y. Hashimoto ◽  
T. Hayakawa ◽  
...  
Keyword(s):  
Dental Pulp ◽  
Electron Microscopic Observation ◽  
Branching Morphogenesis ◽  
Collagen Fibrils ◽  
Electron Microscopic ◽  
Active Involvement ◽  
Interstitial Collagens ◽  
Cleft Formation

An interstitial collagenase was purified from the explant medium of bovine dental pulp and was shown to degrade collagens I and III but not IV and V. The enzyme halted cleft initiation in the epithelium of 12-day mouse embryonic submandibular glands in vitro, indicating the active involvement of interstitial collagens in the branching morphogenesis. Transmission electron microscopic observation of the intact 12-day gland without any clefts showed the scattered localization of a few collagen fibrils at the epithelial-mesenchymal interface of the bulb and also revealed the presence of numerous microfibrils around the stalk. Collagen bundles were regularly seen close to the wavy basal lamina at the bottom of clefts of the intact 13-day gland and 12-day gland cultured for 17 h under normal conditions. Mesenchymal cells were found in the clefts together with the frequent localization of peripheral nerve fibres and capillary endothelial cells. The collagen bundles were more often observed in the 12-day gland cultured in the presence of bovine dental pulp collagenase inhibitor, which had been shown to enhance cleft formation. In contrast, collagen fibrils were rarely found at the epithelial-mesenchymal interface of the 12-day gland cultured in the presence of Clostridial or bovine dental pulp collagenase. The findings indicated that the formation of interstitial collagen bundles is essential to form clefts in the epithelium both in vivo and in vitro.

scholarly journals STUDIES ON THE IN VIVO AND IN VITRO MULTIPLICATION OF THE LDH VIRUS OF MICE

1966 ◽  
Vol 123 (6) ◽  
pp. 985-998 ◽  
Author(s):  
Herman G. du Buy ◽  
Martin L. Johnson
Keyword(s):  
Lymph Nodes ◽  
Ascitic Fluid ◽  
Virus Titer ◽  
Electron Microscopic Observation ◽  
Peritoneal Macrophages ◽  
Virus Multiplication ◽  
Target Cells ◽  
Electron Microscopic

In vivo analysis of the virus titer in various loci, 24 hr after infection, showed that a titer similar to that in the blood plasma was found in the ascitic fluid of Erlich ascites cancer-bearing mice, and in lymph nodes, spleen, and thymus, i.e. loci which contain macrophages as a common cell type. However, only in the lymph nodes and in the ascitic fluid did the increase in virus titer precede or parallel the increase in the plasma. The LDH virus titer in the plasma of X-irradiated mice was similar to that of control mice, eliminating radiation-sensitive cells but not macrophages as target cells of the virus. Electron microscopic observation of infected lymph node cells revealed the presence of two types of particles: one consisting of small densely stained annuli, about 25 mµ in diameter and one of similar dense annuli with a halo extending the diameter to about 50 mµ. Such particles were repeatedly observed within single or double membraned vesicles. In vitro, the LDH virus multiplied only in cultures of mouse peritoneal macrophages, maintained in medium 199 with 10% FBS. The virus titer could be maintained for at least 33 days, during eleven serial passages, involving an overall dilution factor of 1011. These results corroborate the findings of Evans and Salaman, who used peritoneal macrophages maintained in Eagle's medium and 5 to 10% lamb serum. However, in the serial passage experiments reported here, the virus titer could only be maintained following trypsinization of each successive inoculum. The role of macrophages as the target cell for LDH virus multiplication in vivo is discussed.

Cytological changes induced by platinum-thymine in sarcoma-180 cells: Electron microscopy study

1990 ◽  
Vol 48 (3) ◽  
pp. 290-291
Author(s):  
Gustav Ofosu
Keyword(s):  
Mammalian Cells ◽  
Antitumor Agent ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Limiting Factor ◽  
Sarcoma 180 ◽  
Electron Microscopic ◽  
Cytological Changes

Platinum-thymine has been found to be a potent antitumor agent, which is quite soluble in water, and lack nephrotoxicity as the dose-limiting factor. The drug has been shown to interact with DNA and inhibits DNA, RNA and protein synthesis in mammalian cells in vitro. This investigation was undertaken to elucidate the cytotoxic effects of piatinum-thymine on sarcoma-180 cells in vitro ultrastructurally, Sarcoma-180 tumor bearing mice were treated with intraperitoneal injection of platinum-thymine 40mg/kg. A concentration of 60μg/ml dose of platinum-thymine was used in in vitro experiments. Treatments were at varying time intervals of 3, 7 and 21 days for in vivo experiments, and 30, 60 and 120 min., 6, 12, and 24th in vitro. Controls were not treated with platinum-thymine.Electron microscopic analyses of the treated cells in vivo and in vitro showed drastic cytotoxic effect.

scholarly journals Upregulation of ETV2 Expression Promotes Endothelial Differentiation of Human Dental Pulp Stem Cells

2021 ◽  
Vol 30 ◽  
pp. 096368972097873
Author(s):  
Jing Li ◽  
Youming Zhu ◽  
Na Li ◽  
Tao Wu ◽  
Xianyu Zheng ◽  
...  
Keyword(s):  
Protein Expression ◽  
Dental Pulp ◽  
Tube Formation ◽  
Endothelial Differentiation ◽  
Cell Source ◽  
Lentiviral Infection ◽  
Mrna And Protein Expression ◽  
Human Dental Pulp

The lack of vasculogenesis often hampers the survivability and integration of newly engineered tissue grafts within the host. Autologous endothelial cells (ECs) are an ideal cell source for neovascularization, but they are limited by their scarcity, lack of proliferative capacity, and donor site morbidity upon isolation. The objective of this study was to determine whether differentiation of human dental pulp stem cells (DPSCs) into the endothelial lineage can be enhanced by recombinant ETV2 overexpression. DPSCs were extracted from fresh dental pulp tissues. ETV2 overexpression in DPSCs was achieved by lentiviral infection and cellular morphological changes were evaluated. The mRNA and protein expression levels of endothelial-specific markers were assessed through quantitative real-time polymerase chain reaction, western blot, immunofluorescence staining, and flow cytometry. The tube formation assay and Matrigel plug assay were also performed to evaluate the angiogenic potential of the ETV2-transduced cells in vitro and in vivo, respectively. Additionally, proteomic analysis was performed to analyze global changes in protein expression following ETV2 overexpression. After lentiviral infection, ETV2-overexpressing DPSCs showed endothelial-like morphology. Compared with control DPSCs, significantly higher mRNA and protein expression levels of endothelial-specific genes, including CD31, VE-Cadherin, VEGFR1, and VEGFR2, were detected in ETV2-overexpressing DPSCs. Moreover, ETV2 overexpression enhanced capillary-like tube formation on Matrigel in vitro, as well as neovascularization in vivo. In addition, comparative proteomic profiling showed that ETV2 overexpression upregulated the expression of vascular endothelial growth factor (VEGF) receptors, which was indicative of increased VEGF signaling. Taken together, our results indicate that ETV2 overexpression significantly enhanced the endothelial differentiation of DPSCs. Thus, this study shows that DPSCs can be a promising candidate cell source for tissue engineering applications.

scholarly journals Plant Recombinant Human Collagen Type I Hydrogels for Corneal Regeneration

2021 ◽  
Author(s):  
Michel Haagdorens ◽  
Elle Edin ◽  
Per Fagerholm ◽  
Marc Groleau ◽  
Zvi Shtein ◽  
...  
Keyword(s):  
Collagen Type ◽  
Collagen Type I ◽  
Collagen Fibrils ◽  
Type I ◽  
Safe Alternative ◽  
Human Donor ◽  
Human Collagen ◽  
Donor Corneas

Abstract Purpose To determine feasibility of plant-derived recombinant human collagen type I (RHCI) for use in corneal regenerative implants Methods RHCI was crosslinked with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) to form hydrogels. Application of shear force to liquid crystalline RHCI aligned the collagen fibrils. Both aligned and random hydrogels were evaluated for mechanical and optical properties, as well as in vitro biocompatibility. Further evaluation was performed in vivo by subcutaneous implantation in rats and corneal implantation in Göttingen minipigs. Results Spontaneous crosslinking of randomly aligned RHCI (rRHCI) formed robust, transparent hydrogels that were sufficient for implantation. Aligning the RHCI (aRHCI) resulted in thicker collagen fibrils forming an opaque hydrogel with insufficient transverse mechanical strength for surgical manipulation. rRHCI showed minimal inflammation when implanted subcutaneously in rats. The corneal implants in minipigs showed that rRHCI hydrogels promoted regeneration of corneal epithelium, stroma, and nerves; some myofibroblasts were seen in the regenerated neo-corneas. Conclusion Plant-derived RHCI was used to fabricate a hydrogel that is transparent, mechanically stable, and biocompatible when grafted as corneal implants in minipigs. Plant-derived collagen is determined to be a safe alternative to allografts, animal collagens, or yeast-derived recombinant human collagen for tissue engineering applications. The main advantage is that unlike donor corneas or yeast-produced collagen, the RHCI supply is potentially unlimited due to the high yields of this production method. Lay Summary A severe shortage of human-donor corneas for transplantation has led scientists to develop synthetic alternatives. Here, recombinant human collagen type I made of tobacco plants through genetic engineering was tested for use in making corneal implants. We made strong, transparent hydrogels that were tested by implanting subcutaneously in rats and in the corneas of minipigs. We showed that the plant collagen was biocompatible and was able to stably regenerate the corneas of minipigs comparable to yeast-produced recombinant collagen that we previously tested in clinical trials. The advantage of the plant collagen is that the supply is potentially limitless.

scholarly journals POLYMORPHONUCLEAR LEUKOCYTES IN IMMUNOLOGIC REACTIONS

1966 ◽  
Vol 124 (4) ◽  
pp. 733-752 ◽  
Author(s):  
Charles G. Cochrane ◽  
Barbara S. Aikin
Keyword(s):  
Basement Membrane ◽  
Polymorphonuclear Leukocytes ◽  
Electron Microscopic Observation ◽  
Severe Damage ◽  
Electron Microscopic ◽  
Cationic Proteins ◽  
Vascular Basement Membrane ◽  
Arthus Phenomenon ◽  
Immunologic Reactions

Vascular basement membrane was disrupted in the presence of polymorphonuclear leukocytes (PMN's) during two immunologic reactions: The Arthus phenomenon and the reaction to locally injected antibody to vascular basement membrane. This disruption was evidenced by (a) the inability of the basement membrane to retain circulating carbon, by (b) loss of antigenic constituents, and by (c) electron microscopic observation showing actual gaps in the structure of the vascular basement membrane. The factors within PMN's responsible for damage to isolated glomerular basement membrane in vitro were found by isolation procedures to be cathepsins D and E. Cationic proteins of PMN's were separable from the cathepsins. While inducing vascular permeability upon injection, these basic proteins failed to inflict the severe damage to the basement membrane observed in Arthus and antibasement membrane reactions. It is concluded that the full expression of these immunologic lesions requires destruction of the basement membrane possibly brought about by cathepsins D and E. Some of the physicochemical properties of these pathologically active leukocytic factors are given.

P-EP013. Superior migration propensity of dental pulp stem cells in in vitro and in vivo models of excitotoxic neurodegeneration

2021 ◽  
Vol 132 (8) ◽  
pp. e82-e83
Author(s):  
Sivapriya Senthilkumar ◽  
Chaitra Venugopal ◽  
K. Shobha ◽  
Bindu M. Kutty ◽  
Anandh Dhanushkodi
Keyword(s):  
Stem Cells ◽  
Dental Pulp ◽  
Dental Pulp Stem Cells ◽  
In Vivo Models ◽  
Migration Propensity

scholarly journals Shift in collagen type as an early response to induction of the metanephric mesenchyme.

1981 ◽  
Vol 89 (2) ◽  
pp. 276-283 ◽  
Author(s):  
P Ekblom ◽  
E Lehtonen ◽  
L Saxén ◽  
R Timpl
Keyword(s):  
Basal Lamina ◽  
Type Iv Collagen ◽  
Early Response ◽  
Type I ◽  
Metanephric Mesenchyme ◽  
Type Iv ◽  
Interstitial Collagens ◽  
Membrane Components

Conversion of the nephrogenic mesenchyme into epithelial tubules requires an inductive stimulus from the ureter bud. Here we show with immunofluorescence techniques that the undifferentiated mesenchyme before induction expresses uniformly type I and type III collagens. Induction both in vivo and in vitro leads to a loss of these proteins and to the appearance of basement membrane components including type IV collagen. This change correlates both spatially and temporally with the determination of the mesenchyme and precedes and morphological events. During morphogenesis, type IV collagen concentrates at the borders of the developing tubular structures where, by electron microscopy, a thin, often discontinuous basal lamina was seen to cover the first pretubular cell aggregates. Subsequently, the differentiating tubules were surrounded by a well-developed basal lamina. No loss of the interstitial collagens was seen in the metanephric mesenchyme when brought into contact with noninducing tissues or when cultured alone. Similar observations were made with nonnephrogenic mesenchyme (salivary, lung) when exposed to various heterotypic tissues known to induce tubules in the nephrogenic mesenchyme. The sequential shift in the composition of the extracellular matrix from an interstitial, mesenchymal type to a differentiated, epithelial type is so far the first detectable response of the nephrogenic mesenchyme to the tubule-inducing signal.

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