Reepithelialization of Orthotopic Tracheal Allografts Prevents Rejection after Withdrawal of Immunosuppression

2005 ◽  
Vol 114 (4) ◽  
pp. 279-288 ◽  
Author(s):  
Satish Govindaraj ◽  
Elena Fedorova ◽  
Eric M. Genden ◽  
Houtan Chaboki ◽  
Jonathan S. Bromberg ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cyclosporine A ◽  
Allograft Rejection ◽  
Lymphocyte Subpopulation ◽  
Ciliated Epithelium ◽  
Prior Work ◽  
Cellular Infiltrate ◽  
Tracheal Transplantation

Prior work has demonstrated that immunosuppressed orthotopic tracheal allografts undergo progressive reepithelialization over a 48-day period with recipient-derived tracheal epithelium. We hypothesized that reepithelialization of tracheal allografts would prevent rejection after withdrawal of immunosuppression. BALB/c murine tracheal grafts were transplanted orthotopically into either syngeneic or allogeneic C57/BL6 recipients. The recipients were either not immunosuppressed, immunosuppressed with cyclosporine A (10 mg/kg per day) continuously, or immunosuppressed for 48 days and then withdrawn from immunosuppression. The grafts were assessed for acute and chronic rejection 10 days and 50 days after immunosuppression withdrawal. The immunosuppressed allograft recipients maintained a ciliated epithelium acutely and chronically after immunosuppression withdrawal. Ten days after immunosuppression withdrawal, there was a mild cellular infiltrate, which resolved 50 days after withdrawal. Electron microscopy, lymphocyte subpopulation assays, and lamina propria analysis demonstrated that immunosuppression withdrawal did not result in tracheal allograft rejection. In vitro and in vivo assessments did not demonstrate evidence of systemic or local immune tolerance. We conclude that reepithelialization of orthotopic tracheal allografts with recipient-derived mucosa prevents rejection of allograft segments. Tracheal transplantation may require only transient immunosuppression, which can be withdrawn after tracheal reepithelialization.

scholarly journals Assessment of SnFe2O4 Nanoparticles for Potential Application in Theranostics: Synthesis, Characterization, In Vitro, and In Vivo Toxicity

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 825
Author(s):  
Saman Sargazi ◽  
Mohammad Reza Hajinezhad ◽  
Abbas Rahdar ◽  
Muhammad Nadeem Zafar ◽  
Aneesa Awan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
A549 Cells ◽  
In Vitro Cytotoxicity ◽  
Hek293 Cells ◽  
Hydrothermal Route ◽  
X Ray ◽  
Tin Chloride ◽  
Bet Analysis

In this research, tin ferrite (SnFe2O4) NPs were synthesized via hydrothermal route using ferric chloride and tin chloride as precursors and were then characterized in terms of morphology and structure using Fourier-transform infrared spectroscopy (FTIR), Ultraviolet–visible spectroscopy (UV-Vis), X-ray power diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and Brunauer–Emmett–Teller (BET) method. The obtained UV-Vis spectra was used to measure band gap energy of as-prepared SnFe2O4 NPs. XRD confirmed the spinel structure of NPs, while SEM and TEM analyses disclosed the size of NPs in the range of 15–50 nm and revealed the spherical shape of NPs. Moreover, energy dispersive X-ray spectroscopy (EDS) and BET analysis was carried out to estimate elemental composition and specific surface area, respectively. In vitro cytotoxicity of the synthesized NPs were studied on normal (HUVEC, HEK293) and cancerous (A549) human cell lines. HUVEC cells were resistant to SnFe2O4 NPs; while a significant decrease in the viability of HEK293 cells was observed when treated with higher concentrations of SnFe2O4 NPs. Furthermore, SnFe2O4 NPs induced dramatic cytotoxicity against A549 cells. For in vivo study, rats received SnFe2O4 NPs at dosages of 0, 0.1, 1, and 10 mg/kg. The 10 mg/kg dose increased serum blood urea nitrogen and creatinine compared to the controls (P < 0.05). The pathology showed necrosis in the liver, heart, and lungs, and the greatest damages were related to the kidneys. Overall, the in vivo and in vitro experiments showed that SnFe2O4 NPs at high doses had toxic effects on lung, liver and kidney cells without inducing toxicity to HUVECs. Further studies are warranted to fully elucidate the side effects of SnFe2O4 NPs for their application in theranostics.

scholarly journals Cemp1-p3 Peptide Promotes the Transformation of Octacalcium Phosphate into Hydroxyapatite Crystals

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1131
Author(s):  
Maricela Santana ◽  
Gonzalo Montoya ◽  
Raúl Herrera ◽  
Lía Hoz ◽  
Enrique Romo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Octacalcium Phosphate ◽  
Sequence Motifs ◽  
Simple Method ◽  
Transmission Electron ◽  
Precursor Phase ◽  
Mineralized Tissues ◽  
Potent Growth

Dental cementum contains unique molecules that regulate the mineralization process in vitro and in vivo, such as cementum protein 1 (CEMP1). This protein possesses amino acid sequence motifs like the human recombinant CEMP1 with biological activity. This novel cementum protein 1-derived peptide (CEMP1-p3, from the CEMP1’s N-terminal domain: (QPLPKGCAAVKAEVGIPAPH), consists of 20 amino acids. Hydroxyapatite (HA) crystals could be obtained through the combination of the amorphous precursor phase and macromolecules such as proteins and peptides. We used a simple method to synthesize peptide/hydroxyapatite nanocomposites using OCP and CEMP1-p3. The characterization of the crystals through scanning electron microscopy (SEM), powder X-ray diffraction (XRD), high--resolution transmission electron microscopy (HRTEM), and Raman spectroscopy revealed that CEMP1-p3 transformed OCP into hydroxyapatite (HA) under constant ionic strength and in a buffered solution. CEMP1-p3 binds and highly adsorbs to OCP and is a potent growth stimulator of OCP crystals. CEMP1-p3 fosters the transformation of OCP into HA crystals with crystalline planes (300) and (004) that correspond to the cell of hexagonal HA. Octacalcium phosphate crystals treated with CEMP1-p3 grown in simulated physiological buffer acquired hexagonal arrangement corresponding to HA. These findings provide new insights into the potential application of CEMP1-p3 on possible biomimetic approaches to generate materials for the repair and regeneration of mineralized tissues, or restorative materials in the orthopedic field.

scholarly journals ELECTRON MICROSCOPY OF PLASMA-CELL TUMORS OF THE MOUSE

1961 ◽  
Vol 9 (2) ◽  
pp. 369-381 ◽  
Author(s):  
D. F. Parsons ◽  
M. A. Bender ◽  
E. B. Darden ◽  
Guthrie T. Pratt ◽  
D. L. Lindsley
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Complex Structure ◽  
Granular Body ◽  
Virus Particles ◽  
Culture Cells ◽  
Large Numbers ◽  
Tumor Agent

The X5563 tumor has been grown in tissue culture. Cells similar to those of the original tumor migrated from the explant and attached to the glass walls of the culture vessels. Electron microscopy showed that large numbers of particles, similar in morphology to virus particles, were associated with these cells after 7 days of culture. The two principal types of particles found in the tumor in vivo appear to be present in vitro. Many more of these particles, however, were larger and showed a more complex structure. Whereas the particles were mainly localized inside endoplasmic reticulum or the Golgi zone in the tumors in vivo, in the tissue culture the majority of the particles were associated with the plasma membrane and were found outside of the cells. The relation of the particles to the granular body is discussed as well as a possible relation to the mammary tumor agent.

scholarly journals Human Islet Amyloid Polypeptide Fibril Binding to Catalase: A Transmission Electron Microscopy and Microplate Study

2010 ◽  
Vol 10 ◽  
pp. 879-893 ◽  
Author(s):  
Nathaniel G. N. Milton ◽  
J. Robin Harris
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Islet Amyloid Polypeptide ◽  
Amyloid Β ◽  
Human Islet ◽  
Islet Amyloid ◽  
Human Islet Amyloid Polypeptide ◽  
Transmission Electron

The diabetes-associated human islet amyloid polypeptide (IAPP) is a 37-amino-acid peptide that forms fibrilsin vitroandin vivo. Human IAPP fibrils are toxic in a similar manner to Alzheimer's amyloid-β (Aβ) and prion protein (PrP) fibrils. Previous studies have shown that catalase binds to Aβ fibrils and appears to recognize a region containing the Gly-Ala-Ile-Ile sequence that is similar to the Gly-Ala-Ile-Leu sequence found in human IAPP residues 24-27. This study presents a transmission electron microscopy (TEM)—based analysis of fibril formation and the binding of human erythrocyte catalase to IAPP fibrils. The results show that human IAPP 1-37, 8-37, and 20-29 peptides form fibrils with diverse and polymorphic structures. All three forms of IAPP bound catalase, and complexes of IAPP 1-37 or 8-37 with catalase were identified by immunoassay. The binding of biotinylated IAPP to catalase was high affinity with a KDof 0.77nM, and could be inhibited by either human or rat IAPP 1-37 and 8-37 forms. Fibrils formed by the PrP 118-135 peptide with a Gly-Ala-Val-Val sequence also bound catalase. These results suggest that catalase recognizes a Gly-Ala-Ile-Leu—like sequence in amyloid fibril-forming peptides. For IAPP 1-37 and 8-37, the catalase binding was primarily directed towards fibrillar rather than ribbon-like structures, suggesting differences in the accessibility of the human IAPP 24-27 Gly-Ala-Ile-Leu region. This suggests that catalase may be able to discriminate between different structural forms of IAPP fibrils. The ability of catalase to bind IAPP, Aβ, and PrP fibrils demonstrates the presence of similar accessible structural motifs that may be targets for antiamyloid therapeutic development.

Corrosive behaviour of Amplatzer® devices in experimental and biological environments

2002 ◽  
Vol 12 (3) ◽  
pp. 260-265 ◽  
Author(s):  
Huafu Kong ◽  
James L. Wilkinson ◽  
James Y. Coe ◽  
Xiaoping Gu ◽  
Myra Urness ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Oxide Layer ◽  
Titanium Oxide ◽  
Saline Solution ◽  
Nickel Titanium ◽  
Cardiac Transplant ◽  
Titanium Oxide Layer ◽  
Device Placement

Purpose: Nitinol, a nickel-titanium alloy, is a valuable material in the construction of interventional endoluminal devices because of its biocompatibility, super elasticity, high resiliency and shape memory. The possibility of nickel toxicity has been raised with devices constructed of Nitinol. Our investigation examines the long-term corrosive behavior of this alloy in experimental and biological environments. Methods: We performed three levels of study. Microscopic examination was made of 64 devices of various sizes, randomly selected from 240 Amplatzer® Septal Occluders that had been exposed to saline solution at 37°C for fourteen months. All samples were studied by electron microscopy ranging from 50 to 5000 times magnification. We also studied microscopically 3 Amplatzer® devices explanted 18–36 months after implantation in dogs, and 2 Amplatzer Septal Occluders removed from patients 18 months (cardiac transplant) and 19 months (died of causes unrelated to device placement) after implantation, which were examined grossly and by electron microscopy up to 5000 times magnification. We then measured the levels of nickel in the blood using inductive plasma mass spectroscopy in 19 patients with implanted Amplatzer® devices, making measurements before and 6 months after implantation. Results: Electron microscopy showed an intact titanium oxide layer with no evidence of corrosion in vitro and in vivo. One explanted device in direct contact with the platinum leads of a pacemaker for eighteen months showed minor pitting of the titanium oxide layer believed to be galvanic in nature. No wire fractures were found in vitro after cycle testing with 400 million cycles, nor in devices taken from the animals and humans. Biochemical studies showed no significant elevation of levels of nickel levels after implantation. Conclusion: Nitinol wire of Amplatzer® septal occlusion devices is resistant to corrosion when exposed to physiologic saline solution, and in experimental animals as well as humans. A device in contact with a platinum pacemaker electrode developed minimal pitting of the titanium oxide layer, believed to be galvanic in nature and of no structural or clinical significance. There is no increase of concentrations of nickel in the blood of patients who have received Amplatzer® nitinol devices. These favorable testing results reveal that nickel-titanium is an inert, corrosion resistant alloy.

Effect of cyclosporine A treatment in vitro on pancreatic islet allograft rejection

1997 ◽  
Vol 29 (5) ◽  
pp. 2494-2497
Author(s):  
J. Mendola ◽  
H. Corominola ◽  
E. Esmatjes ◽  
A. Saenz ◽  
L. Fernandez-Cruz ◽  
...  
Keyword(s):  
Pancreatic Islet ◽  
Cyclosporine A ◽  
Allograft Rejection ◽  
Islet Allograft ◽  
Pancreatic Islet Allograft

scholarly journals AN ANALYSIS OF COLLAGEN SECRETION BY ESTABLISHED MOUSE FIBROBLAST LINES

1964 ◽  
Vol 22 (1) ◽  
pp. 227-258 ◽  
Author(s):  
Burton Goldberg ◽  
Howard Green
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Mouse Fibroblast ◽  
In Vivo Studies ◽  
In Vitro Synthesis ◽  
Collagen Secretion ◽  
Golgi System ◽  
Alternative Theories

In vitro synthesis of collagen by established mouse fibroblast lines has been examined by electron microscopy. During rapid growth (log phase), when collagen could not be detected in the cultures, the cells lacked a well developed granular ergastoplasm and Golgi system. Upon cessation of growth (stationary phase), collagen accumulated in the cultures and the cells demonstrated highly developed granular and smooth ergastoplasm. Collagen appeared to be synthesized in the rough-surfaced endoplasmic reticulum and to be transported as a soluble protein to the cell surface by vesicular elements of the agranular ergastoplasm. Fusion of the limiting membranes of these vesicles with the cell membrane permitted the discharge of the soluble collagen into the extracellular space, where fibrils of two diameter distributions formed. The secretion of collagen is concluded to be of the merocrine type. Alternative theories of collagen secretion are discussed and the data for established lines compared with the results of other in vitro and in vivo studies of collagen fibrillogenesis.

Intercellular contacts at the epithelial—mesenchymal interface of the developing rat submandibular gland in vitro

Development ◽  
1977 ◽  
Vol 39 (1) ◽  
pp. 71-77
Author(s):  
Leslie S. Cutler
Keyword(s):  
Electron Microscopy ◽  
Submandibular Gland ◽  
Functional Differentiation ◽  
Developmental Sequence ◽  
Millipore Filter ◽  
Intercellular Contacts ◽  
Rat Submandibular Gland ◽  
Developing Rat

An ultrastructural study of the development of the rat submandibular gland (SMG) anlage in vitro was undertaken to determine if epithelial-mesenchymal and epithelial-nerve contacts were integral events in the differentiation of the gland in vitro as they are in vivo. SMG rudiments were removed at the stalk-bulb stage (15 days in utero) and cultured for 6 days on a millipore filter in supplemented McCoy's 5A media. Rudiments were taken at daily intervals, fixed and processed for electron microscopy. The overall development of the explanted rudiments closely paralleled their maturation in vivo although cultured glands lagged 24–36 h behind their normal counterparts. Direct epithelial-mesenchymal contacts were seen after the morphogenetic patterning of the gland had been established but prior to functional differentiation of the rudiment. Epithelial-nerve contacts were not seen although healthy axons were seen in the stroma throughout the culture period. The study indicates that epithelial-nerve contacts are probably not required for morphogenesis of cytodifferentiation of the rat SMG. However, direct epithelial-mesenchymal contacts appear to be an integral part of the developmental sequence of the rat SMG.

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