A novel fibrinogen variant (fibrinogen Seoul II; AαGln328Pro) characterized by impaired fibrin α-chain cross-linking

Blood ◽  
2006 ◽  
Vol 108 (6) ◽  
pp. 1919-1924 ◽  
Author(s):  
Rojin Park ◽  
Hyun-Ju Doh ◽  
Seong-Soo A. An ◽  
Jong-Rak Choi ◽  
Kwang-Hoe Chung ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Myocardial Infarction ◽  
Scanning Electron Microscopy ◽  
Factor Xiii ◽  
Cross Linking ◽  
Mutation Site ◽  
Polymer Formation ◽  
Tissue Plasminogen ◽  
Α Chain ◽  
Scanning Electron

AbstractWe report a novel fibrinogen variant (fibrinogen Seoul II), which has a heterozygous point mutation from CAA to CCA leading to AαGln328Pro. The mutation site is among several glutamine residues that serve as α-chain cross-linking acceptor sites. Fibrinogen Seoul II was found in a 51-year-old male patient and his family in Seoul, Korea. The patient was diagnosed with myocardial infarction at age 43. Eight years later he was admitted to the emergency room due to recurrence of the disease, where he expired under treatment with tissue plasminogen activator (t-PA). Fibrin polymerization curves, made using purified fibrinogen from the patient's relatives, showed a decreased final turbidity, suggesting Seoul II fibrin clots are composed of thinner fibers. This supposition was verified using scanning electron microscopy. Alpha-polymer formation by the mutant fibrinogen upon thrombin treatment in the presence of factor XIII and calcium was distinctly impaired. This result confirms that the residue Aα328 plays a pivotal role in α-chain cross-linking.

scholarly journals Intraocular Lens Opacification following Intracameral Injection of Recombinant Tissue Plasminogen Activator to Treat Inflammatory Membranes after Cataract Surgery

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Simon S. M. Fung ◽  
Evripidis Sykakis ◽  
Niaz M. Islam ◽  
Hadi J. Zambarakji ◽  
Ramin Khoramnia ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Cataract Surgery ◽  
Anterior Chamber ◽  
Plasminogen Activator ◽  
Recombinant Tissue Plasminogen Activator ◽  
X Ray ◽  
Tissue Plasminogen ◽  
Scanning Electron

Purpose. To report 7 cases of intraocular lens (IOL) opacification following treatment of postoperative anterior chamber fibrin with recombinant tissue plasminogen activator (rtPA) after cataract surgery. Methods. Retrospective case series of 7 eyes in 7 patients who developed IOL opacification after receiving rtPA for anterior chamber inflammatory membrane formation resulting from phacoemulsification cataract surgery. Three explanted IOLs were investigated with light microscopy, histochemical analysis, scanning electron microscopy, and X-ray spectrometry. Results. All patients underwent uncomplicated cataract surgery and posterior chamber hydrophilic IOL implantation. Anterior chamber inflammatory membranes developed between 1 and 4 weeks of surgery and were treated with intracameral rtPA. IOL opacification was noted between 4 weeks and 6 years after rtPA treatment with reduced visual acuity, and IOL exchange was carried out in 3 patients. Light microscopy evaluation revealed diffuse fine granular deposits on the anterior surface/subsurface of IOL optic that stained positive for calcium salts. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS) confirmed the presence of calcium and phosphate on the IOL. Conclusions. Intracameral rtPA, though rapidly effective in the treatment of anterior chamber inflammatory membranes following cataract surgery, may be associated with IOL opacification.

scholarly journals Fibrinogen variant BβD432A has normal polymerization but does not bind knob “B”

Blood ◽  
2009 ◽  
Vol 113 (18) ◽  
pp. 4425-4430 ◽  
Author(s):  
Sheryl R. Bowley ◽  
Susan T. Lord
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cross Linking ◽  
Dimer Formation ◽  
Fibrin Polymerization ◽  
Per Se ◽  
Clot Structure ◽  
Scanning Electron

AbstractFibrinogen residue Bβ432Asp is part of hole “b” that interacts with knob “B,” whose sequence starts with Gly-His-Arg-Pro-amide (GHRP). Because previous studies showed BβD432A has normal polymerization, we hypothesized that Bβ432Asp is not critical for knob “B” binding and that new knob-hole interactions would compensate for the loss of this Asp residue. To test this hypothesis, we solved the crystal structure of fragment D from BβD432A. Surprisingly, the structure (rfD-BβD432A+GH) showed the peptide GHRP was not bound to hole “b.” We then re-evaluated the polymerization of this variant by examining clot turbidity, clot structure, and the rate of FXIIIa cross-linking. The turbidity and the rate of γ-γ dimer formation for BβD432A were indistinguishable compared with normal fibrinogen. Scanning electron microscopy showed no significant differences between the clots of BβD432A and normal, but the thrombin-derived clots had thicker fibers than clots obtained from batroxobin, suggesting that cleavage of FpB is more important than “B:b” interactions. We conclude that hole “b” and “B:b” knob-hole binding per se have no influence on fibrin polymerization.

Cell attachment effects of collagen nanoparticles on crosslinked electrospun nanofibers

2020 ◽  
pp. 039139882094773
Author(s):  
Fereshteh Ziaei Amiri ◽  
Zaiddodine Pashandi ◽  
Nasrin Lotfibakhshaiesh ◽  
Mohammad Javad Mirzaie Parsa ◽  
Hossein Ghanbari ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Extracellular Matrix ◽  
Cell Viability ◽  
Matrix Protein ◽  
Cellular Proliferation ◽  
Cell Attachment ◽  
Extracellular Matrix Protein ◽  
Cross Linking ◽  
Scanning Electron

Since collagen is naturally a main extracellular matrix protein, it has been applied widely in skin’s tissue engineering scaffolds to mimics the characteristics of extracellular matrix for proper transplantation of living cells. However, there are challenges that come with application of this natural polymer such as high solubility in aqueous environments which requires further consideration such as chemically cross-linking in order to stabilization. But these treatments also affect its functionality and finally cellular behaviors on scaffold. In this research we evaluated the suitability of collagen nanofibers versus collagen nanoparticles for cell adhesion and viability on glutaraldehyde cross-linked scaffolds. Appling a dual-pump electrospining machine a blend PCL-Gelatin from one side and collagen nanofibers or collagen nanoparticles from the other side were collected on the collector. The fabricated scaffolds were characterized by scanning electron microscopy, contact angle, and mechanical analysis. The cell viability, adhesion and morphology were studied respectively using MTT assay, hoechst staining and scanning electron microscopy. The results indicated significantly improvement of cell viability, adhesion and better spreading on scaffolds with collagen nanoparticles than collagen nanofibers. It seems changes in surface morphology, viscoelastic moduli and swelling ability following cross-linking with glutaraldehyde in scaffold with collagen nanoparticles are still favorable for cellular proliferation. Based on these results, in the case of glutaraldehyde cross-linking, application of collagen nanoparticles rather than collagen nanofibers in tissue regeneration scaffolds will better mimic the extracellular matrix characteristics; and preserve the viability and adhesion of seeded cells.

Clot formation, lysis and ultrastructure in patients with acute phase myocardial infarction

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
A Siniarski ◽  
S.R Baker ◽  
C Duval ◽  
G Gajos ◽  
J Nessler ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Myocardial Infarction ◽  
Coronary Artery Disease ◽  
Scanning Electron Microscopy ◽  
Acute Phase ◽  
Funding Source ◽  
Healthy Controls ◽  
Artery Disease ◽  
Clot Structure ◽  
Scanning Electron

Abstract Background/Introduction Patients with established coronary artery disease have impaired clot structure and lysis. Prior research has compared patients with myocardial infarction to those with stable coronary artery disease (without a healthy reference), or patients after myocardial ischemia. The role of clot structure in the acute phase of the disease is unknown. Purpose Investigate clot structure in the acute phase of myocardial infarction (AMI) compared to healthy controls. Methods Plasma clots from AMI patients (within 12 hours of symptoms onset) or healthy controls were analyzed by turbidity and lysis. Clot pore size was determined by permeation. Clot ultrastructure was determined by confocal and scanning electron microscopy. Average fiber radius and protofibril packing were investigated by turbidimetry. Results Analysis on clot formation, using turbidity, showed increased lag time (24%, p<0.05), suggesting changes in protofibril packing and increased fiber size for AMI patients compared to controls. Additionally, AMI clots formed more quickly as evidenced by average rate of clotting (2.9-fold increase, p<0.001) and time to maximum absorbance (38% decrease, p<0.0001). Decreased plasminogen in AMI patients (23%, p<0.05) had strong effects on clot lysis, including increased time to half lysis (1.72-fold, p<0.0001) and increased time to maximum lysis rate (7.96-fold, p<0.0001). Taken together, these results suggest that AMI patients form less porous clots made from densely packed fibers with decreased numbers of protofibrils, which was confirmed using permeation (1.05-fold decrease, p<0.0001), confocal (Figure 1) and scanning electron microscopy (46% increase, p<0.0001), and turbidimetry (16% decrease, p<0.05) respectively. Conclusions Plasma from patients with AMI form denser and less permeable clots that lyse more slowly than healthy controls. These data show marked abnormalities in clot ultrastructure that contribute to the high risk of thrombosis during the acute phase of myocardial infarction, which has not shown in previous investigations. Figure 1. Confocal microscopy of AMI vs. controls Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): Jagiellonian University Medical College to G.G. (N41/DBS/000096) and BHF Programme Grant to S.R.B. and R.A.S.A. (RG/18/11/34036).

Synthesis of AA-based SAR interpenetrated with PVA and AM

2013 ◽  
Vol 20 (4) ◽  
pp. 379-382
Author(s):  
Wenzheng Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Polyvinyl Acetate ◽  
Ammonium Persulfate ◽  
Cross Linking ◽  
Interpenetrating Network ◽  
Sodium Hydrogen ◽  
Maximum Water ◽  
Superabsorbent Resin ◽  
Scanning Electron

AbstractIn this paper, an interpenetrating network of acrylic acid (AA)-based superabsorbent resin (SAR) with polyvinyl acetate (PVA) and acrylamide (AM) was synthesized by copolymerizing partly neutralized AA, AM and PVA with ammonium persulfate/sodium hydrogen sulfite (APS/SHS) as the radical initiating system and N,N-methylene bisacrylamide as cross-linking agent in an aqueous copolymerization system at 60°C. This type of SAR exhibited excellent properties such as higher water and saline absorbency compared with AA-based SAR. The maximum water and saline absorbency of SAR was 1050 and 125 ml/g, respectively. Those effects were well explained by photographic morphologies obtained using scanning electron microscopy.

scholarly journals Modified pectin as imprinting substrate to immobilize pectinase via both adsorption and crosslinking

BioResources ◽  
2019 ◽  
Vol 14 (4) ◽  
pp. 9364-9374
Author(s):  
Jing Xiao ◽  
Ziyuan Li ◽  
Jian Sun ◽  
Qinzheng Yang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Enzyme Activity ◽  
Broad Spectrum ◽  
Relative Activity ◽  
Cross Linking ◽  
Juice Clarification ◽  
Α Helix ◽  
Β Sheet ◽  
Scanning Electron

A broad-spectrum substrate-imprinted adsorption and crosslinking double immobilized pectinase (SDP) was prepared using a universal modified pectin obtained through enzymatic hydrolysis as the imprinting substrate. Its structure was characterized by infrared spectroscopy, circular dichroism, and scanning electron microscopy. The results showed that 1) cross-linking increased the Schiff base in SDP, 2) immobilization barely changed the secondary structure such as α-helix and β-sheet of SDP, and 3) adhesives were evenly distributed on the surface after immobilization. Studies on the enzymatic properties of SDP showed that the substrate imprinting significantly improved heat resistance and neutralization resistance of SDP. For example, the relative activity of SDP at 35 to 75 °C and at pH 4.4 to 6.5 was 5% and 15% more than that of the adsorption and crosslinking double immobilized pectinase (DP), respectively. In addition, after 8 cycles of use, the relative enzyme activity of SDP still reached 39.5%. Moreover, use of SDP decreased the cation demand in whitewater by 10% compared with DP. Overall, the use of a broad-spectrum substrate for imprinting to obtain SDP provides a new idea and method for using pectinase in in complex systems such as juice clarification and wastewater treatment.

Evaluation of Modified Isobutylene-Isoprene Rubber Cryogels as Sorbents for Oil Removal

2014 ◽  
Vol 955-959 ◽  
pp. 671-675
Author(s):  
Wen Bo Chai ◽  
Xiao Yan Liu ◽  
Xin Ying Zhang ◽  
Jun Chen Zou ◽  
Li Fei Dong
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Lubricating Oil ◽  
Cross Linking ◽  
Oil Removal ◽  
Uptake Capacity ◽  
Freeze Thaw ◽  
Contact Angle Analysis ◽  
Scanning Electron ◽  
Isoprene Rubber

Two new kinds of modified isobutylene-isoprene rubber (IIR) oil absorbers were successfully prepared via freeze-thaw method. In order to further improve IIR oil-sorbents performance, graphite and nanosilica were chosen as modifiers. The cryogels were prepared cross-linking of IIR containing modifier in benzene at-5 °C, using sulfur monochloride as crosslinker. The modified IIR structures were characterized by using scanning electron microscopy (SEM) and contact angle analysis (CA). The results show that graphite-modified IIR exhibit much higher uptake capacity than silica-modified. The sorption capacity of the best graphite-modified sample reaches 19.68 g.g-1for crude oil, 19.98 g.g-1for diesel and 19.50 g.g-1for lubricating oil, respectively. The adsorbed liquids can be removed by centrifuging and the recovered materials could also be used more than 30 cycles. This study demonstrated graphite-modified IIR are more excellent and recommendable materials for oil removal.

scholarly journals Increasing Thermal Stability of Gelatin by UV-Induced Cross-Linking with Glucose

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Evan M. Masutani ◽  
Christopher K. Kinoshita ◽  
Travis T. Tanaka ◽  
Andrew K. D. Ellison ◽  
Brandon A. Yoza
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Cross Linking ◽  
Cross Link ◽  
Cell Scaffold ◽  
Link Formation ◽  
Potential Use ◽  
Thermal Stability Of ◽  
Scanning Electron

The effects of ultraviolet (254 nm) radiation on a hydrated gelatin-glucose matrix were investigated for the development of a physiologically thermostable substrate for potential use in cell scaffold production. Experiments conducted with a differential scanning calorimeter indicate that ultraviolet irradiation of gelatin-glucose hydrogels dramatically increases thermal stability such that no melting is observed at temperatures of at least 90°C. The addition of glucose significantly increases the yield of cross-linked product, suggesting that glucose has a role in cross-link formation. Comparisons of lyophilized samples using scanning electron microscopy show that irradiated materials have visibly different densities.

scholarly journals Preparation and Properties of Decellularized Sheep Kidney Derived Matrix Scaffolds

2022 ◽  
Vol 2160 (1) ◽  
pp. 012014
Author(s):  
Le Zheng ◽  
Shuangshuang Zheng ◽  
Zilong Chen ◽  
Xiangqin Li ◽  
Chunyan Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Cell Attachment ◽  
Cross Linking ◽  
Adipose Derived Stem Cells ◽  
The Poor ◽  
Attachment Sites ◽  
Histological Staining ◽  
Scanning Electron

Abstract Scaffolds from tissues or organs have nanoscale microstructures. Derived matrix scaffolds prepared by decellularized method can provide more cell attachment sites, which is conducive to cell adhesion, proliferation, differentiation and other physiological activities on scaffolds. In this study, the sheep kidney decellularized matrix scaffold was prepared by the method of decellularization. Due to the poor mechanical properties of the decellularized matrix, the cross linking method was adopted to enhance its mechanical properties. The decellularization efficiency of sheep renal matrix scaffolds was observed by scanning electron microscopy and histological staining, and the biocompatibility of the scaffolds was investigated by inoculating adipose derived stem cells. It was found that the scaffold had good decellularization effect and good pore structure.

Pathogenesis of Human Hair Defects

1974 ◽  
Vol 32 ◽  
pp. 12-13
Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Human Hair ◽  
Standard Techniques ◽  
Scanning Electron

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.

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