AN EXTRACT OP FEVERFEW INHIBITS INTERACTION OP HUMAN PLATELETS WITH COLLAGEN SUBSTRATES

1987 ◽  
Author(s):  
W Lösche ◽  
A V Mazurov ◽  
W A Groenewegen ◽  
S A Heptinstall ◽  
V S Repin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Herbal Remedy ◽  
Platelet Rich Plasma ◽  
Human Platelets ◽  
Tanacetum Parthenium ◽  
Ancient Times ◽  
Platelet Spreading ◽  
Dose Dependent ◽  
Scanning Electron

Feverfew (Tanacetum parthenium) has been used since ancient times as a herbal remedy for migraine, fever and arthritis. Recently it has been shown that extracts of feverfew inhibit aggregatory and secretory responses in human platelets induced by various soluble agonists.The interaction of platelets with surfaces coated with human collagens of type III (C III) and IV (C IV) has been studied by measuring the deposition of 51-Cr-labelled platelets and by scanning electron microscopy. Experiments were performed using platelet-rich plasma (PRP) and suspensions of gel-filtered platelets. Platelets were deposited on C III mostly as surface-bound aggregates. In contrast they were deposited on C IV mostly as spread forms of individual cells. Formation of aggregates on C III was more extensive for PRP than for GPP; in contrast platelet spreading on C IV was more extensive for GPP than for PRP.Feverfew extract inhibited the deposition of 51-Cr-labelled platelets on both C III and C IV in a dose dependent way. Similar concentrations of extract were needed to inhibit the formation of surface-bound aggregates and to inhibit platelet spreading in both PRP and GPP.The results indicate that feverfew may have antithrombotic potential in addition to its claimed benefit in certain clinicalconditions.

Defects of Platelet Function Recognized by X-Ray Imaging and Scanning Electron Microscopy

1985 ◽  
Vol 43 ◽  
pp. 610-613
Author(s):  
M.G. Baldini ◽  
S. Morinaga ◽  
D. Minasian ◽  
R. Feder ◽  
D. Sayre ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Biology ◽  
Imaging Technique ◽  
Human Platelets ◽  
X Rays ◽  
X Ray ◽  
X Ray Imaging ◽  
Complex Phenomena ◽  
Scanning Electron

Contact X-ray imaging is presently developing as an important imaging technique in cell biology. Our recent studies on human platelets have demonstrated that the cytoskeleton of these cells contains photondense structures which can preferentially be imaged by soft X-ray imaging. Our present research has dealt with platelet activation, i.e., the complex phenomena which precede platelet appregation and are associated with profound changes in platelet cytoskeleton. Human platelets suspended in plasma were used. Whole cell mounts were fixed and dehydrated, then exposed to a stationary source of soft X-rays as previously described. Developed replicas and respective grids were studied by scanning electron microscopy (SEM).

scholarly journals Fibrinopeptide A release is necessary for effective B:b interactions in polymerisation of variant fibrinogens with impaired A:a interactions

2013 ◽  
Vol 109 (02) ◽  
pp. 221-228 ◽  
Author(s):  
Keisuke Soya ◽  
Fumiko Terasawa ◽  
Nobuo Okumura
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fibrin Clot ◽  
Fibrinopeptide A ◽  
Thrombin Cleavage ◽  
No Release ◽  
Per Se ◽  
Clot Structure ◽  
Dose Dependent ◽  
Scanning Electron

SummaryFibrin polymerisation is mediated by interactions between knobs ‘A’ and ‘B’ exposed by thrombin cleavage, and holes ‘a’ and ‘b’. We demonstrated markedly delayed thrombin-catalysed fibrin polymerisation, through B:b interactions alone, of recombinant γD364H-fibrinogen with impaired hole ‘a’. To determine whether recombinant variant fibrinogens with no release of fibrinopeptide A (FpA) polymerise similarly to γD364H-fibrinogen, we examined two variant fibrinogens with substitutions altering knob ‘A’, Aα17A- and Aα17C-fibrinogen. We examined thrombin- or batroxobin-catalysed fibrinopeptide release by HPLC, fibrin clot formation by turbidity and fibrin clot structure by scanning electron microscopy (SEM) and compared the results of the variants with those for γD364H-fibrinogen. Thrombin-catalysed FpA release of Aα17A-fibrinogen was substantially delayed and none observed for Aα17C-fibrinogen; fibrinopeptide B (FpB) release was delayed for all variants. All variant fibrinogens showed substantially impaired thrombin-catalysed polymerisation; for Aα17A-fibrinogen it was delayed less, and for Aα17C more than for γD364H-fibrinogen. No variants polymerised with batroxobin, which exposed only knob ‘A’. The inhibition of variant fibrinogens’ polymerisation was dose-dependent on the concentration of either GPRP or GHRP, and both peptides that block holes ‘b’. SEM showed that the variant clots from Aα17A- and γD364H-fibrinogen had uniform, ordered fibres, thicker than normal, whereas Aα17C-fibrinogen formed less organised clots with shorter, thinner, and tapered ends. These results demonstrate that FpA release per se is necessary for effective B:b interactions during polymerisation of variant fibrinogens with impaired A:a interactions.

Scanning electron microscopy and microbiological evaluation of equine burn wound repair after platelet-rich plasma gel treatment

Burns ◽  
2012 ◽  
Vol 38 (7) ◽  
pp. 1058-1065 ◽  
Author(s):  
Felipe B. Maciel ◽  
Rafael DeRossi ◽  
Tiago J.C. Módolo ◽  
Ronaldo C. Pagliosa ◽  
Cássia R.J. Leal ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Wound Repair ◽  
Platelet Rich Plasma ◽  
Burn Wound ◽  
Gel Treatment ◽  
Scanning Electron

Loading AKBA on surface of silver nanoparticles to improve their sedative-hypnotic and anti-inflammatory efficacies

Nanomedicine ◽  
2019 ◽  
Vol 14 (21) ◽  
pp. 2783-2798
Author(s):  
Ajmal Khan ◽  
Ahmed Al-Harrasi ◽  
Najeeb Ur Rehman ◽  
Rizwana Sarwar ◽  
Touqeer Ahmad ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silver Nanoparticles ◽  
Water Solubility ◽  
Boswellic Acid ◽  
Transmission Electron ◽  
Anti Inflammatory ◽  
Compound Materials ◽  
Dose Dependent ◽  
Scanning Electron

Aim: Acetyl-11-keto- β-boswellic acid (AKBA) is a potent anti-inflammatory compound limited by its low water solubility and bioavailability. To load AKBA on silver nanoparticles (AgNPs) to improve bioavailability and water solubility of the compound. Materials & methods: AKBA-AgNPs were chemically synthesized and characterized by UV–Vis spectrophotometry, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. AKBA and AKBA-Ag were studied for their sedative-hypnotic and anti-inflammatory efficacies. Results: Pretreatment with AKBA or AKBA-Ag caused significant dose-dependent sedative-hypnotic effects at 5 and 10 mg/kg intraperitoneal. The effects of AKBA-loaded AgNPs caused pronounced changes in mice compared with those of AKBA, and the AKBA-AgNPs demonstrated anti-inflammatory effects that were superior to those of AKBA. Conclusion: The loading of AKBA on nanoparticles improved its pharmacokinetic effects, and capacity for drug delivery.

scholarly journals Endotoxin-induced changes in human platelet membranes: morphologic evidence

Blood ◽  
1978 ◽  
Vol 51 (3) ◽  
pp. 487-495 ◽  
Author(s):  
DH Ausprunk ◽  
J Das
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Human Platelet ◽  
Human Platelets ◽  
Free Medium ◽  
Platelet Surface ◽  
Low Concentrations ◽  
Induced Changes ◽  
Scanning Electron

Abstract Interaction between human platelets and bacterial endotoxin was studied in vitro with transmission and scanning electron microscopy. Washed human platelets, whose aggregation was blocked with apyrase, were incubated in a plasma-free medium containing crude endotoxin that had previously been complexed with copper. Thirty minutes of incubation resulted in adherence of endotoxin particles to the platelet surface, breaks in the platelet plasma membrane with apparent attempts at repair, pseudoped formation, and centralization of platelet organelles. Copper appeared to potentiate these phenomena, since neither Cu2+ at low concentrations nor endotoxin alone altered the morphology of the platelet membrane. This platelet-endotoxin interaction may be an intermediary step in the detoxification and clearance of endotoxin from the plasma.

scholarly journals Endotoxin-induced changes in human platelet membranes: morphologic evidence

Blood ◽  
1978 ◽  
Vol 51 (3) ◽  
pp. 487-495
Author(s):  
DH Ausprunk ◽  
J Das
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Human Platelet ◽  
Human Platelets ◽  
Free Medium ◽  
Platelet Surface ◽  
Low Concentrations ◽  
Induced Changes ◽  
Scanning Electron

Interaction between human platelets and bacterial endotoxin was studied in vitro with transmission and scanning electron microscopy. Washed human platelets, whose aggregation was blocked with apyrase, were incubated in a plasma-free medium containing crude endotoxin that had previously been complexed with copper. Thirty minutes of incubation resulted in adherence of endotoxin particles to the platelet surface, breaks in the platelet plasma membrane with apparent attempts at repair, pseudoped formation, and centralization of platelet organelles. Copper appeared to potentiate these phenomena, since neither Cu2+ at low concentrations nor endotoxin alone altered the morphology of the platelet membrane. This platelet-endotoxin interaction may be an intermediary step in the detoxification and clearance of endotoxin from the plasma.

Thrombin-Mediated Platelet Activation of Lysed Whole Blood and Platelet-Rich Plasma: A Comparison Between Platelet Activation Markers and Ultrastructural Alterations

2016 ◽  
Vol 22 (3) ◽  
pp. 630-639 ◽  
Author(s):  
Tanya N. Augustine ◽  
Wendy J. van der Spuy ◽  
Lindsay L. Kaberry ◽  
Millicent Shayi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Flow Cytometry ◽  
Platelet Activation ◽  
Diagnostic Tool ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Ultrastructural Changes ◽  
Ultrastructural Alterations ◽  
Scanning Electron

AbstractPlatelet ultrastructural alterations representing spurious activation have been identified in pathological conditions. A limitation of platelet studies is that sample preparation may lead to artifactual activation processes which may confound results, impacting the use of scanning electron microscopy as a supplemental diagnostic tool. We used scanning electron microscopy and flow cytometry to analyze platelet activation in platelet-rich plasma (PRP) and whole blood (WB) samples. PRP generated using a single high g force centrifugation, and WB samples treated with a red blood cell lysis buffer, were exposed to increasing concentrations of the agonist thrombin. Platelets in lysed WB samples responded to thrombin by elevating the activation marker CD62p definitively, with corresponding ultrastructural changes indicating activation. Conversely, CD62p expression in PRP preparations remained static. Ultrastructural analysis revealed fully activated platelets even under low concentration thrombin stimulation, with considerable fibrin deposition. It is proposed that the method for PRP production induced premature platelet activation, preventable by using an inhibitor of platelet aggregation and fibrin polymerization. Nevertheless, our results show a definitive correspondence between flow cytometry and scanning electron microscopy in platelet activation studies, highlighting the potential of the latter technique as a supplemental diagnostic tool.

Autochthonous and Allochthonous Micro and Nanoparticles in Deteriorated Lime Mortars of Historical Buildings

2009 ◽  
Vol 8 ◽  
pp. 35-45 ◽  
Author(s):  
Jorge Sanjurjo-Sánchez ◽  
Juan Ramón Vidal Romaní ◽  
Carlos Alves
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Air Pollution ◽  
Calcium Sulphate ◽  
Gaseous Pollutants ◽  
Historical Buildings ◽  
Lime Mortars ◽  
Ancient Times ◽  
Environmental Causes ◽  
Scanning Electron

Lime mortars have been commonly used in historical buildings since ancient times. The progressive deterioration of these mortars by air pollution and other environmental causes hinders the assessment of the original composition. The weakening of the mortar structure is due to dissolution and formation of calcium sulphate layers because of the interaction with SOx gaseous pollutants. Also, pollution particles can be incorporated to the mortar because of dissolution by rainwater or runoff. Scanning Electron Microscopy (SEM) studies allow us to distinguish allochthonous and autochthonous micro- and nanoparticles in order to identify original intact plasters. By comparing these intact to deteriorated mortars from both air polluted and non-polluted areas it is possible to indentify and preserve the original mortar composition as a key step to project future façade cleaning and restorations.

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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