A SPECTROPHOTOMETRIC METHOD FOR FIBRIN CLOT LYSIS ASSAY

1987 ◽  
Author(s):  
A Electricwala
Keyword(s):  
Biological Fluids ◽  
Fibrin Clot ◽  
Calibration Graph ◽  
Assay Method ◽  
Clot Lysis ◽  
End Point ◽  
Straight Line ◽  
Absorbance Peak ◽  
The Many

Clot lysis assay is one of the many methods being used to quantitate tissue plasminogen activator in biological fluids and other media. It has been suggested that this assay may be less reproducible and subject to error due to variation between laboratories in determining the end point of clot lysis, especially at lower concentrations of the activator. It has been found that this assay method can be semi-automated by monitoring the absorbance of the fibrin clot, and determining the end point, in a spectrophotometer. Standard clots containing varying concentrations of tPA are prepared in semi-micro cuvettes, held at 37° C and the absorbance monitored continuosly at 600nm. The turbidity of the sample is increased near its lytic time, which results in a sharp absorbance peak. The time elapsed from the start to the appearence of this peak is taken as the lytic time of the clot. Using standard prepration of tPA, a straight line calibration graph of log lytic time versus log concentration is obtained, with a standard deviation for each determination of ± 5%. This method has the advantage of being simple, reproducible and less prone to operator error.

Study on Using EDXRF for the Determination of Gold Coating Thickness

2014 ◽  
Vol 974 ◽  
pp. 225-229 ◽  
Author(s):  
Meor Yusoff Meor Sulaiman ◽  
Masliana Muslimin
Keyword(s):  
Coating Thickness ◽  
Accurate Result ◽  
Calibration Graph ◽  
Gold Coating ◽  
Absorption Effect ◽  
Straight Line ◽  
Coating Methods ◽  
Electroplated Coating ◽  
The Relationship

The paper presents a study on the development of an analysis procedure for determining of gold coating thickness using the EDXRF technique. Gold coating thickness was measured by relating the counts under the Au Lα peak to its thickness value. In order to get a reasonably accurate result, a calibration graph was plotted using five gold-coated reference standards of different thicknesses. The calibration graph shows a straight line for thin coating measurement until 0.9μm. Beyond this point, the relationship was exponential and this may be resulted from the self-absorption effect. Quantitative analysis was then performed on three different samples namely two gold-coated jewelry samples and a phone connector sample. Result from the phone connector analysis seems to agree with the manufacturer’s gold coating value. Results from the analysis of gold-coated jewelry enable to differentiate the two articles as coated by using the gold wash and gold electroplated coating methods.

scholarly journals A simple assay method for the activity of plasma antiplasmin and SK-activated plasmin on the basis of fibrin clot lysis

1978 ◽  
Vol 9 (1) ◽  
pp. 55-59
Author(s):  
Toyohiko ARIGA ◽  
Hiroko SAWAI ◽  
Hideo IMAI ◽  
Jun KATO ◽  
Chen-Hsiung HUANG ◽  
...  
Keyword(s):  
Fibrin Clot ◽  
Assay Method ◽  
Clot Lysis

scholarly journals Construction of different types of ion-selective electrodes and validation of direct potentiometric determination of phenytoin sodium

2010 ◽  
Vol 8 (4) ◽  
pp. 937-945 ◽  
Author(s):  
Maha El-Tohamy ◽  
Sawsan Razeq ◽  
Magda El-Maamly ◽  
Abdalla Shalaby
Keyword(s):  
Biological Fluids ◽  
Pharmaceutical Preparations ◽  
Sodium Concentration ◽  
Calibration Graph ◽  
Membrane Composition ◽  
Tungstosilicic Acid ◽  
Phenytoin Sodium ◽  
And Performance ◽  
Ph Range

AbstractThe construction and performance characteristics of phenytoin sodium selective electrodes are detailed. Two types of electrodes: plastic membrane I and coated wire II, were constructed based on the incorporation of phenytoin sodium with tungstosilicic acid. The influence of membrane composition, kind of plasticizer, pH of the test solution, soaking time and the electrodes’ foreign ions were investigated. The electrodes showed a Nernstian response with a mean calibration graph slope of 30.9±0.1 and 28.9±0.1 mV decade−1 at 25°C for electrode I and II respectively, over a phenytoin sodium concentration range of 5×10−3−5×10−6 M and 1×10−3−1×10−6 M with a detection limit 1.3×10−6 M and 2.5×10−7 M for electrode I and II, respectively. The electrodes gave average selective precision and were usable within the pH range 6–10. Interference studies from common cations, alkaloids, sugars, amino acids and drug excipients are reported. The results obtained by the proposed electrodes were also applied successfully for the determination of the drug in pharmaceutical preparations and biological fluids.

Plasminogen Assay by Means of the Lysis Time Method

1965 ◽  
Vol 14 (01/02) ◽  
pp. 127-144 ◽  
Author(s):  
W Berg ◽  
K Korsan-Bengtsen ◽  
J Ygge
Keyword(s):  
Maximal Activity ◽  
Fibrin Clot ◽  
Order Reaction ◽  
Zero Order ◽  
Fibrinogen Concentration ◽  
Plasmin Activity ◽  
Consecutive Reactions ◽  
Lysis Time ◽  
Straight Line

SummaryThe lysis time method for the determination of plasminogen has been investigated using plasminogen-free thrombin and fibrinogen preparations.The experiments have shown that the lysis of a fibrin clot is the result of two consecutive reactions: the formation of fibrin which proceeds as a first order reaction and the degradation of fibrin which proceeds as a zero order reaction. Plasminogen is activated in a separate reaction. If the rate of the fibrin formation is much greater than the rate of degradation, the lysis of the fibrin clot is approximately of zero order in fibrin. The lysis time will then be inversely proportional to the plasmin concentration and proportional to the fibrinogen concentration. In a double logaritmic system the correlation between lysis time and plasmin activity is a straight line with a slope of 135°.Plasminogen is rapidly activated with streptokinase. Maximal activation is obtained only with a certain streptokinase concentration. Higher concentrations inactivate plasmin and with lower concentrations, the maximal activity is never reached. A spontaneous inactivation is seen after about 30 minutes. With urokinase, a higher maximal plasminogen activity is obtained than with streptokinase. Urokinase in higher concentrations does not inactivate plasmin.A standard assay for determination of plasminogen by the lysis time method has been worked out and is based on these results.

The many faces of STEM in materials science

1991 ◽  
Vol 49 ◽  
pp. 440-441
Author(s):  
John Silcox
Keyword(s):  
Materials Science ◽  
Auger Spectroscopy ◽  
Dark Field ◽  
High Tc Superconductors ◽  
High Tc ◽  
Acoustic Environment ◽  
Electromagnetic Vibration ◽  
The Many ◽  
Serial Mode

Determination of the microstructure and microchemistry of small features often provides the insight needed for the understanding of processes in real materials. In many cases, it is not adequate to use microscopy alone. Microdiffraction and microspectroscopic information such as EELS, X-ray microprobe analysis and Auger spectroscopy can all contribute vital parts of the picture. For a number of reasons, dedicated STEM offers considerable promise as a quantitative instrument. In this paper, we review progress towards effective quantitative use of STEM with illustrations drawn from studies of high Tc superconductors, compound semiconductors and metallization of H-terminated silicon.Intrinsically, STEM is a quantitative instrument. Images are acquired directly by detectors in serial mode which is particularly convenient for digital image acquisition, control and display. The VG HB501A at Cornell has been installed in a particularly stable electromagnetic, vibration and acoustic environment. Care has been paid to achieving UHV conditions (i.e., 10-10 Torr). Finally, it has been interfaced with a VAX 3200 work station by Kirkland. This permits, for example, the acquisition of bright field (or energy loss) images and dark field images simultaneously as quantitative arrays in perfect registration.

Enhanced information from biological materials through technological improvements in cryo-electron microscopy

1992 ◽  
Vol 50 (1) ◽  
pp. 788-789
Author(s):  
Marc J.C. de Jong ◽  
Wim M. Busing ◽  
Max T. Otten
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Biological Materials ◽  
Electron Crystallography ◽  
Cryo Electron Microscopy ◽  
Transmission Electron ◽  
The Many ◽  
Technological Improvements ◽  
Beam Damage

Biological materials damage rapidly in the electron beam, limiting the amount of information that can be obtained in the transmission electron microscope. The discovery that observation at cryo temperatures strongly reduces beam damage (in addition to making it unnecessaiy to use chemical fixatives, dehydration agents and stains, which introduce artefacts) has given an important step forward to preserving the ‘live’ situation and makes it possible to study the relation between function, chemical composition and morphology.Among the many cryo-applications, the most challenging is perhaps the determination of the atomic structure. Henderson and co-workers were able to determine the structure of the purple membrane by electron crystallography, providing an understanding of the membrane's working as a proton pump. As far as understood at present, the main stumbling block in achieving high resolution appears to be a random movement of atoms or molecules in the specimen within a fraction of a second after exposure to the electron beam, which destroys the highest-resolution detail sought.

The Collaborative Medical and Behavioral Management of Chronic Cough

2009 ◽  
Vol 19 (2) ◽  
pp. 49-57
Author(s):  
Brian E. Petty ◽  
Seth H. Dailey
Keyword(s):  
Medical Care ◽  
Chronic Cough ◽  
Therapeutic Management ◽  
Ambulatory Setting ◽  
Behavioral Management ◽  
Speech Language Pathologists ◽  
Speech Language Pathologist ◽  
The Many ◽  
Frequent Reason

Abstract Chronic cough is the most frequent reason cited by patients for seeking medical care in an ambulatory setting and may account for 10% to 38% of a pulmonologist's practice. Because chronic cough can be caused by or correlated with a wide array of disorders and behaviors, the diagnosis of etiologic factors and determination of appropriate therapeutic management in these cases can prove to be daunting for the physician and speech-language pathologist alike. This article will describe the phenomenon of chronic cough, discuss the many etiologic factors to consider, and review some of the more common ways in which speech-language pathologists and physicians collaborate to treat this challenging condition.

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