On the albumin dependence of measurements of free thyroxin. I. Technical performance of seven methods.

1986 ◽  
Vol 32 (1) ◽  
pp. 108-115 ◽  
Author(s):  
G Csako ◽  
M H Zweig ◽  
C Benson ◽  
M Ruddel

Abstract We evaluated three one-step (analog) and two two-step radioimmunoassay for free thyroxin (FT4), and a FT4 index calculated from the total T4 (TT4) and thyroxin-binding globulin (TBG) ratio for technical performance, for correlation with the reference FT4 method (equilibrium dialysis), and for dependence on TBG and albumin concentrations. The one-step methods (Amerlex, Coat-A-Count, and GammaCoat) showed greater precision than the two-step procedures (GammaCoat and Spiria). Results by the latter two techniques, however, correlated better with those by equilibrium dialysis than did those by the analog methods or by TT4/TBG. Only the GammaCoat two-step method had a slight but statistically significant (inverse) correlation with TBG concentration. All three analog methods and TT4/TBG showed a marked dependence on albumin concentration, whereas the Spiria technique showed only a slight dependence. Only equilibrium dialysis was independent of both the TBG and albumin concentration. Thus, despite their good precision, the analog (one-step) FT4 methods and the TT4/TBG approach cannot be expected to produce valid results when the concentration of albumin in serum is abnormally low or high.

1987 ◽  
Vol 33 (1) ◽  
pp. 87-92 ◽  
Author(s):  
G Csako ◽  
M H Zweig ◽  
C Benson ◽  
M Ruddel

Abstract We studied the relation between thyroxin-binding proteins and free thyroxin (FT4) measurements by five radioimmunoassays (RIA) and an FT4 index (FT4I) in patients with non-thyroidal illness (NTI). The one-step FT4 RIAs and the FT4I frequently failed to identify the true FT4 status (as determined by equilibrium dialysis) of NTI patients. In these patients, falsely low FT4 results with one-step RIAs and FT4I were associated with decreasing total T3 and T4 concentrations, which, furthermore, paralleled decreasing serum albumin concentrations. All NTI patients with "low T3, low T4 syndrome" had subnormal albumin concentration. The two-step RIAs and equilibrium dialysis showed normal FT4 concentrations in most patients with NTI. However, sera from a subset of NTI patients with "low T3 syndrome" gave above-normal FT4 results with these methods. From their predictably poor performance in the presence of a subnormal albumin concentration, we conclude that the one-step FT4 RIAs and FT4I are inappropriate for testing the thyrometabolic status of NTI patients.


Author(s):  
Ifael Yerosias Mauleti ◽  
Suhendro Suhendro ◽  
Leonard Nainggolan ◽  
Martin Rumende

BACKGROUND<br />Dengue infection is an acute viral infection, in the natural history of which plasma leakage may occur, resulting in shock followed by tissue hypoxia, with death as the final outcome if not treated properly. The purpose of this study was to determine the correlation of the hematocrit, serum albumin concentration, and the presence of pleural effusion or ascites, with hyperlactatemia in adult dengue patients.<br /><br />METHODS<br />A cross-sectional study was conducted on 62 subjects. The inclusion criteria were: diagnosed dengue viral infection, age &gt;14 years, fever during three consecutive days, and hyperlactatemia. Serum albumin was measured on an Advia 1800 analyzer using the bromocresol green method. The lactate oxidase method was used to determine serum lactate levels. Pleural effusion and/or ascites was determined using an ultrasound scanner (Xario SSA-660 A, Toshiba, Japan). The Pearson correlation test was used to analyze the data.<br /> <br />RESULTS<br />There was no significant correlation between the hematocrit (r=0.11; p=0.301), serum albumin (r=0.003;p=0.981), and pleural effusion or ascites (r=0.75; p=0.692) with serum lactate levels. However, in patients aged &gt;30 years there was a significant inverse correlation between serum albumin and lactate levels (r =- 0.663;p=0.026). <br /><br />CONCLUSION<br />This study demonstrated a significant inverse correlation between albumin and serum lactate levels in dengue patients aged &gt; 30 years. This can aid in the early recognition and prompt management of at-risk patients to reduce morbidity and mortality.


1990 ◽  
Vol 36 (7) ◽  
pp. 1355-1360 ◽  
Author(s):  
P Nuutila ◽  
P Koskinen ◽  
K Irjala ◽  
L Linko ◽  
H L Kaihola ◽  
...  

Abstract We measured concentrations of free thyroxin (FT4) in serum by using two new two-step FT4 assays--a solid-phase two-step radioimmunoassay. Spectria, and a time-resolved fluoroimmunoassay. Delfia--and compared the results with those by a two-step FT4 assay (RIA-gnost), a one-step FT4 analog assay (Amerlex-M), and FT4 measured after equilibrium dialysis. The new FT4 assays classified 30 hypothyroid and 43 hyperthyroid patients (untreated) well. In 138 patients with nonthyroidal illness (NTI) and in late pregnancy (n = 36), fewer subnormal FT4 values were reported by Spectria (P less than 0.001), Delfia (P less than 0.001), and RIA-gnost (P less than 0.01) than by Amerlex-M. The results of the Spectria and Delfia methods correlated with the results of the dialysis method (r = 0.76) in NTI patients and pregnancy, and were in better agreement with the clinical state than was FT4 by Amerlex-M. The FT4 values by Amerlex-M, but not by other methods, correlated with albumin concentration. We conclude that these new two-step methods present good alternatives for FT4 analysis.


1990 ◽  
Vol 9 (3) ◽  
pp. 247-252 ◽  
Author(s):  
Sander Greenland ◽  
Alberto Salvan
Keyword(s):  
One Step ◽  

2018 ◽  
Vol 54 (68) ◽  
pp. 9438-9441 ◽  
Author(s):  
Nathalie M. Pinkerton ◽  
Khadidja Hadri ◽  
Baptiste Amouroux ◽  
Leah Behar ◽  
Christophe Mingotaud ◽  
...  

A novel, one-step method for the synthesis of functional, organic–inorganic hybrid nanoparticles is reported.


Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 658 ◽  
Author(s):  
Xiaohui Yang ◽  
Yi Liu ◽  
Chunjie Yan ◽  
Ronghua Peng ◽  
Hongquan Wang

Geopolymer-TiO2 nanocomposites were prepared by two different techniques, namely the two-step acidification calcination treatment and one-step adding method. The potential photocatalytic activities of geopolymer-TiO2 nanocomposites prepared by the two different methods were tested and compared. Nanocomposites prepared via the one-step process showed better photocatalytic activity. The amount of TiO2 particles loaded on the surface of the foaming materials was investigated by XRD and SEM-Mapping. By comparing with the sample obtained from two-step treatment, the TiO2 particles were distributed uniformly on the surface of the foaming materials for the sample obtained from the one-step method in this study. Results showed that the specific surface area of the geopolymer-TiO2 prepared by the one-step treatment process (28.67 m2/g) was significantly lower than the two-step acidification calcination process (215.04 m2/g), while the photocatalytic efficiency with methylene blue trihydrate (MB) was better. This is due to the more stable structure of geopolymer-TiO2 nanocomposites, the better dispersion and more loading of TiO2 particles on the foaming materials surfaces, leading to the enhanced photocatalytic activity.


Author(s):  
George W. Patrick ◽  
Charles Cuell ◽  
Raymond J. Spiteri ◽  
William Zhang

In the formalism of constrained mechanics, such as that which underlies the SHAKE and RATTLE methods of molecular dynamics, we present an algorithm to convert any one-step integration method to a variational integrator of the same order. The one-step method is arbitrary, and the conversion can be automated, resulting in a powerful and flexible approach to the generation of novel variational integrators.


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