Ammonia production during clot retraction and its use in assay of fibrinoligase.

1977 ◽  
Vol 23 (9) ◽  
pp. 1739-1743 ◽  
Author(s):  
S Mousli ◽  
N W Wakid
Keyword(s):  
Direct Method ◽  
Limiting Factor ◽  
Fibrinogen Concentration ◽  
Ammonia Production ◽  
Clot Retraction ◽  
Ammonia Content ◽  
Shed Blood ◽  
Cross Linkage ◽  
Total Ammonia

Abstract Clotting of recalcified plasma is followed by an increase in its ammonia content that lasts 4 to 6 h. This ammonia production closely parallels the increase in acid-insoluble fibrin, which is evidence that the ammonia results from the action of fibrinoligase. If the clot is removed, ammonia production stops. The initial velocity of ammonia production is directly proportional to the fibrinogen concentration in plasma. Thus the rate-limiting factor in normal shed blood is the fibrinogen concentration. A maximum of 6.4 +/- 1.5 (SD) molecules of ammonia are produced per molecule of fibrinogen. Determination of the total ammonia produced is the fastest direct method of estimating the extent of frbrin cross-linkage in whole plasma. A method is proposed for assaying fibrinoligase, based on the rate of ammonia production in the presence of casein as substrate. Normal values are 7.6 +/- 2.9 (SD) mumol/min per liter of plasma.

scholarly journals Determination of Total Ammonia in Mainstream Smoke

2003 ◽  
Vol 20 (6) ◽  
pp. 389-393 ◽  
Author(s):  
CB Huang ◽  
R Bassfield ◽  
B Dabney ◽  
F Hsu
Keyword(s):  
Federal Trade Commission ◽  
Trapping Efficiency ◽  
Mainstream Smoke ◽  
Ammonia Content ◽  
Sample Stability ◽  
Wide Range ◽  
Acid Acid ◽  
Total Ammonia ◽  
Trapping Devices

AbstractAmmonia is generated in mainstream smoke (MSS) from multiple precursors in tobacco such as amino acids, proteins, nitrates and ammonium salts. Ammonia derived from both the particulate and vapor phases is measured with the particulate phase contributing greater than 80% of the total ammonia. The general approach of the analytical methods involved the collection of MSS by either electrostatic precipitation (EP) or impingers with acidic solution combined with Cambridge filters (CF, 44 or 92 mm) and the analysis of ammonium cations by ion chromatography (IC) with a conductivity detector. The available results from both internal testing and external literature for 1R4F Kentucky reference cigarettes, smoked under Federal Trade Commission (FTC) puffing conditions, showed a wide range of yields from approximately 5 to 18 µg/cig of ammonia. To investigate possible causes for this wide range and to optimize the analytical method, several parameters deemed critical to the results were studied using 1R4F. They include the type of acids (hydrochloric acid, sulfuric acid and malic acid), acid strength (0.005 M to 0.1 M), trapping efficiency and sample stability. The study showed that the type and concentration of acids was not significantly related to the total ammonia content in MSS. The study also indicated that the size and type of trapping devices, such as CF pads, acid treated CF pads and EP tube, did not significantly affect the trapping efficiency.

scholarly journals Determination of Unprotonated Ammonia in Whole Cigarette Smoke

1976 ◽  
Vol 8 (6) ◽  
Author(s):  
C. H. Sloan ◽  
G. P. Morie
Keyword(s):  
Cigarette Smoke ◽  
Free Ammonia ◽  
Ammonium Salts ◽  
Ammonia Content ◽  
Tobacco Cigarette ◽  
Total Ammonia ◽  
Theoretical Amount ◽  
Ammonia Electrode

AbstractThe total ammonia content of smoke is essentially ammonium salts with insignificant amounts of free ammonia. An ammonia electrode was used to experimentally measure the amount of free ammonia in the smoke of several cigarettes and two little cigars. For comparison, the theoretical amount of free ammonia was calculated from the total ammonia content and smoke pH. Free ammonia in domestic filter and non-filter cigarettes ranged from 1 to 4 ng with totaI ammonia contents of 28 to 44 µg. The smoke from a dark tobacco cigarette and Iittle cigar contained 1.2 and 2.4 µg of free NH

Determination of Plasminogen in Human Plasma by the Lysis Time Method

1966 ◽  
Vol 16 (01/02) ◽  
pp. 001-017 ◽  
Author(s):  
W Berg ◽  
K Korsan-Bengtsen ◽  
J Ygge
Keyword(s):  
Human Plasma ◽  
Present Method ◽  
Blood Donors ◽  
Fibrinogen Concentration ◽  
Plasmin Activity ◽  
Time System ◽  
Lysis Time ◽  
High Dilutions ◽  
Single Determination

SummaryA one-stage lysis time system containing fibrinogen, streptokinase, thrombin, and a known, small amount of plasminogen was used to determine plasminogen in plasma.The known amount of plasminogen was added to the system in order to keep the lysis times relatively short when a highly diluted plasma was tested. High dilutions of plasma were used to reduce the influence of the plasma inhibitors.The calculation of the plasminogen concentration was made on the basis of the correlation: “plasminogen = fibrinogen/lysis time” which was valid in the system. The method allowed determination of plasminogen in plasma with varying fibrinogen concentrations, as the fibrinogen concentration in plasma was considered in the calculation.The presence of “spontaneous” plasmin activity in the plasma did not influence the plasminogen determination. Estimated by this method, the plasminogen content in plasma from 32 blood donors aged 25-45 years was 13.1 ±2.4 casein u/ml. The error of a single determination was 0.3 casein u/ml. The plasminogen content in plasma, determined with the present method, is about 3-4 times higher than the content found when a caseinolytic method is used.

Ab initio structure determination of cytochrome c6 by combined reciprocal space-real space approach

2003 ◽  
Vol 218 (1) ◽  
Author(s):  
K. Chowdhury ◽  
S. Ghosh ◽  
M. Mukherjee
Keyword(s):  
Cytochrome C ◽  
Ab Initio ◽  
Structure Determination ◽  
Direct Method ◽  
Real Space ◽  
Reciprocal Space ◽  
Cytochrome C6 ◽  
Ab Initio Structure ◽  
Space Approach

AbstractThe direct method program SAYTAN has been applied successfully to redetermine the structure of cytochrome c

Freezing in Silicon at Large Undercooling

1989 ◽  
Vol 157 ◽  
Author(s):  
P.A. Stolk ◽  
A. Polman ◽  
W.C. Sinke
Keyword(s):  
Interface Temperature ◽  
Limiting Factor ◽  
Time Resolved ◽  
Large Undercooling ◽  
Explosive Crystallization ◽  
Crystallization Speed ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Rate Limiting

ABSTRACTPulsed laser irradiation is used to induce epitaxial explosive crystallization of amorphous silicon layers buried in a (100) oriented crystalline matrix. This process is mediated by a self-propagating liquid layer. Time-resolved determination of the crystallization speed combined with numerical calculation of the interface temperature shows that freezing in silicon saturates at 16 m/s for large undercooling (> 130 K). A comparison between data and different models for melting and freezing indicates that the crystallization behavior at large undercooling can be described correctly if the rate-limiting factor is assumed to be diffusion in liquid Si at the solid/liquid interface.

scholarly journals The determination of the heat of dissociation of fluorine and of the latent heat of vaporisation of lithium

1932 ◽  
Vol 136 (829) ◽  
pp. 76-82 ◽  
Keyword(s):  
High Temperature ◽  
Absorption Spectra ◽  
Latent Heat ◽  
Chemical Reactivity ◽  
Direct Method ◽  
Thermal Methods ◽  
Heat Of Dissociation

The heats of dissociation of chlorine, bromine, and iodine have been determined by thermal methods and estimated to be 58·9, 45·2 and 35·2 kilo-cals. respectively. But no data are yet known concerning the heat of dissociation of fluorine. It is very difficult to subject fluorine to the same treatment as Cl 2 , Br 2 and I 2 ( i. e ., heating to a high temperature in a sealed quartz bulb) owing to its extreme chemical reactivity, and hence no direct method of determining the heat of dissociation of fluorine has yet been devised. In the present paper I have determined it indirectly by interpretation of the absorption spectra of alkali fluorides (for the present only NaF and KF). A short theory of the experiment is given below.

scholarly journals Simultaneous determination of procaine hydrochloride, procainamide hydrochloride and lidocaine by molecular absorption spectrometry

2019 ◽  
pp. 318-324
Author(s):  
Nicoleta Mirela Marin ◽  
Gheorghe Batrinescu ◽  
Mihai Nita-Lazar ◽  
Luoana Florentina Pascu ◽  
Carol Blaziu Lehr
Keyword(s):  
Simultaneous Determination ◽  
Direct Method ◽  
Absorption Spectrometry ◽  
Procaine Hydrochloride ◽  
Zero Crossing ◽  
Multicomponent Analysis ◽  
First Derivative ◽  
Cramer’S Rule ◽  
Derivative Spectrometry

Two spectrometric methods have been developed for quantitative simultaneous determination of procaine hydrochloride (PH·HCl), procainamide hydrochloride (PHA·HCl) and lidocaine (Lid) from synthetic mixture. The methods employed are first derivative spectrometry, using zero crossing method and multicomponent analysis which is based on the additivity law. Using first derivative spectrometry, the wavelength selected for the quantitative determination of PH·HCl was 237 nm for Lid was 242 nm and for PHA·HCl was 290 nm in mixture. The method is linear when the concentration ranged between 6.62-9.93 μg/mL for PH·HCl, 6.43-9.64 for PHA·HCl and 5.56-8.35 for Lid. The multicomponent analysis is a direct method and involves the absorbance measurements of at three different wavelengths. The molar absorption coefficients values were calculated at each wavelength and the concentration of PH·HCl, PHA·HCl and Lid from mixture was determined by solving matrix using Cramer's rule. The recovery of each compound in mixture was calculated and it is 101.4 % for PH·HCl, 100.4 % for PHA·HCl and 98.4 % for Lid.

scholarly journals Routine Determination of Ice Thickness for Cryo-EM Grids

2018 ◽  
Author(s):  
William J. Rice ◽  
Anchi Cheng ◽  
Alex J. Noble ◽  
Edward T. Eng ◽  
Laura Y. Kim ◽  
...  
Keyword(s):  
Data Collection ◽  
Sample Preparation ◽  
Quality Data ◽  
Ice Thickness ◽  
Limiting Factor ◽  
Test Cases ◽  
Slowing Down ◽  
Routine Monitoring ◽  
The Many

AbstractRecent advances in instrumentation and automation have made cryo-EM a popular method for producing near-atomic resolution structures of a variety of proteins and complexes. Sample preparation is still a limiting factor in collecting high quality data. Thickness of the vitreous ice in which the particles are embedded is one of the many variables that need to be optimized for collection of the highest quality data. Here we present two methods, using either an energy filter or scattering outside the objective aperture, to measure ice thickness for potentially every image collected. Unlike geometrical or tomographic methods, these can be implemented directly in the single particle collection workflow without interrupting or significantly slowing down data collection. We describe the methods as implemented into the Leginon/Appion data collection workflow, along with some examples from test cases. Routine monitoring of ice thickness should prove helpful for optimizing sample preparation, data collection, and data processing.

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