Study on growth processes of particles in germane radio frequency discharges using laser light scattering and scanning electron microscopic methods

Abstract A well-characterized in vitro model system composed of thrombin- stimulated gel-filtered human platelets, fibrin-(ogen), plasminogen, and recombinant tissue plasminogen activator (rt-PA) was used to examine the relationship between platelet-fibrin adhesive interactions and the lytic resistance of a platelet-rich thrombus. Laser light scattering kinetic experiments demonstrated that the ligand-mimetic peptide D-RGDW and an anti-alpha IIb beta 3 monoclonal antibody both inhibited clot retraction, but neither integrin-targeted reagent affected the overall delay in lysis of “bulk” fibrin caused by thrombin- stimulated platelets. However, lysis of the model platelet-rich thrombus did proceed some 30% more quickly when treated with a plasminogen activator inhibitor (PAI)-resistant t-PA variant. Taken together, these results confirm that platelet-released PAI-1 is a major determinant of global lytic resistance. Next events occurring during fibrinolysis in the unique microenvironment near the platelet surface were monitored by scanning electron microscopy and quantitative fluorescence microscopy. Scanning electron micrographs of the partially lysed model thrombus in the presence of 200 mumol/L of D-RGDW showed no platelet aggregates, and fibrin was attached by fewer strands to the platelets. Quantitative fluorescence microscopy, using fluorescein- labeled fibrin, showed that fibrin adherent to the surface of thrombin- stimulated platelets lysed 20% to 50% more slowly than bulk fibrin (monitored in parallel by laser light scattering). Furthermore, this microspectroscopic technique showed that D-RGDW reduced the quantity of platelet-bound fibrin, and accelerated lysis near the platelet surface with both native rt-PA and the PAI-resistant variant. These observations suggest that the dense network of fibrin bound to the platelet surface is protected from fibrinolysis by tissue-type plasminogen activators. Further, uncoupling fibrin from its platelet receptors uniquely hastens fibrinolysis at the cell/fibrin interface.

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Uncoupling fibrin from integrin receptors hastens fibrinolysis at the platelet-fibrin interface

Blood ◽

10.1182/blood.v83.4.982.bloodjournal834982 ◽

1994 ◽

Vol 83 (4) ◽

pp. 982-993

Author(s):

JV Braaten ◽

WG Jerome ◽

RR Hantgan

Keyword(s):

Light Scattering ◽

Fluorescence Microscopy ◽

Plasminogen Activator ◽

Laser Light ◽

Laser Light Scattering ◽

Tissue Type ◽

Scanning Electron Micrographs ◽

Platelet Surface ◽

Quantitative Fluorescence ◽

Scanning Electron

A well-characterized in vitro model system composed of thrombin- stimulated gel-filtered human platelets, fibrin-(ogen), plasminogen, and recombinant tissue plasminogen activator (rt-PA) was used to examine the relationship between platelet-fibrin adhesive interactions and the lytic resistance of a platelet-rich thrombus. Laser light scattering kinetic experiments demonstrated that the ligand-mimetic peptide D-RGDW and an anti-alpha IIb beta 3 monoclonal antibody both inhibited clot retraction, but neither integrin-targeted reagent affected the overall delay in lysis of “bulk” fibrin caused by thrombin- stimulated platelets. However, lysis of the model platelet-rich thrombus did proceed some 30% more quickly when treated with a plasminogen activator inhibitor (PAI)-resistant t-PA variant. Taken together, these results confirm that platelet-released PAI-1 is a major determinant of global lytic resistance. Next events occurring during fibrinolysis in the unique microenvironment near the platelet surface were monitored by scanning electron microscopy and quantitative fluorescence microscopy. Scanning electron micrographs of the partially lysed model thrombus in the presence of 200 mumol/L of D-RGDW showed no platelet aggregates, and fibrin was attached by fewer strands to the platelets. Quantitative fluorescence microscopy, using fluorescein- labeled fibrin, showed that fibrin adherent to the surface of thrombin- stimulated platelets lysed 20% to 50% more slowly than bulk fibrin (monitored in parallel by laser light scattering). Furthermore, this microspectroscopic technique showed that D-RGDW reduced the quantity of platelet-bound fibrin, and accelerated lysis near the platelet surface with both native rt-PA and the PAI-resistant variant. These observations suggest that the dense network of fibrin bound to the platelet surface is protected from fibrinolysis by tissue-type plasminogen activators. Further, uncoupling fibrin from its platelet receptors uniquely hastens fibrinolysis at the cell/fibrin interface.

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Scanning Electron Microscopic Study of the Cell Surface

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100062087 ◽

1969 ◽

Vol 27 ◽

pp. 36-37 ◽

Cited By ~ 1

Author(s):

Toichiro Kuwabara

Keyword(s):

Tissue Fluid ◽

Biological Application ◽

Biological Structure ◽

Electron Microscopic ◽

Surface Appearance ◽

Minute Amount ◽

Scanning Electron Microscopic Study ◽

Scanning Electron Microscopic ◽

True Structure ◽

Scanning Electron

Although scanning electron microscopy has a great potential in biological application, there are certain limitations in visualization of the biological structure. Satisfactory techniques to demonstrate natural surfaces of the tissue and the cell have been reported by several investigators. However, it is commonly found that the surface cell membrane is covered with a minute amount of mucin, secretory substance or tissue fluid as physiological, pathological or artefactual condition. These substances give a false surface appearance, especially when the tissue is fixed with strong fixatives. It seems important to remove these coating substances from the surface of the cell for demonstration of the true structure.

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A scanning electron microscopic study on dissolving process of cholesterol gallstones by chenodeoxycholic acid (CDCA)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100083485 ◽

1978 ◽

Vol 36 (2) ◽

pp. 522-523

Author(s):

T. Kanetaka ◽

M. Cho ◽

S. Kawamura ◽

T. Sado ◽

K. Hara

Keyword(s):

Electron Microscope ◽

Chenodeoxycholic Acid ◽

Outer Surface ◽

Electron Microscopic ◽

Cholesterol Gallstones ◽

The Core ◽

Scanning Electron Microscopic Study ◽

Scanning Electron Microscopic ◽

Acceleration Voltage ◽

Scanning Electron

The authors have investigated the dissolution process of human cholesterol gallstones using a scanning electron microscope(SEM). This study was carried out by comparing control gallstones incubated in beagle bile with gallstones obtained from patients who were treated with chenodeoxycholic acid(CDCA).The cholesterol gallstones for this study were obtained from 14 patients. Three control patients were treated without CDCA and eleven patients were treated with CDCA 300-600 mg/day for periods ranging from four to twenty five months. It was confirmed through chemical analysis that these gallstones contained more than 80% cholesterol in both the outer surface and the core.The specimen were obtained from the outer surface and the core of the gallstones. Each specimen was attached to alminum sheet and coated with carbon to 100Å thickness. The SEM observation was made by Hitachi S-550 with 20 kV acceleration voltage and with 60-20, 000X magnification.

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A Comparative Study of Fractographic Replicas

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052845 ◽

1974 ◽

Vol 32 ◽

pp. 566-567

Author(s):

Loren Anderson ◽

Pat Pizzo ◽

Glen Haydon

Keyword(s):

Electron Microscopy ◽

Electron Microscopic Examination ◽

Direct Examination ◽

Electron Microscopic ◽

Reliable Technique ◽

Service Failures ◽

Transmission Electron ◽

Mode Of Failure ◽

Scanning Electron Microscopic ◽

Scanning Electron

Transmission electron microscopy of replicas has long been used to study the fracture surfaces of components which fail in service. Recently, the scanning electron microscope (SEM) has gained popularity because it allows direct examination of the fracture surface. However, the somewhat lower resolution of the SEM coupled with a restriction on the sample size has served to limit the use of this instrument in investigating in-service failures. It is the intent of this paper to show that scanning electron microscopic examination of conventional negative replicas can be a convenient and reliable technique for determining mode of failure.

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A Scanning Electron Microscopic Study of the Uriniferous Tubules

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073556 ◽

1973 ◽

Vol 31 ◽

pp. 622-623

Author(s):

Peter M. Andrews

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Renal Glomerulus ◽

Electron Microscopic ◽

Vascular Perfusion ◽

Scanning Electron Microscopic Study ◽

Scanning Electron Microscopic ◽

Collecting Tubules ◽

Bowman's Capsule ◽

Scanning Electron

Although there have been a number of recent scanning electron microscopic reports on the renal glomerulus, the advantages of scanning electron microscopy have not yet been applied to a systematic study of the uriniferous tubules. In the present investigation, scanning electron microscopy was used to study the ultrastructural morphology of the proximal, distal, thin loop, and collecting tubules. Material for observation was taken from rat kidneys which were fixed by vascular perfusion, sectioned by either cutting or fracturing technigues, and critically point dried.The brush border characterising proximal tubules is first detected on the luminal surface of Bowman's capsule adjacent to the urinary pole orifice. In this region one frequently finds irregular microvilli characterized by broad and flattened bases with occasional bulbous structures protruding from their surfaces.

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