Direct and indirect techniques for free thyroxin compared in patients with nonthyroidal illness. I. Effect of free fatty acids.

1989 ◽  
Vol 35 (1) ◽  
pp. 102-109 ◽  
Author(s):  
G Csako ◽  
M H Zweig ◽  
J Glickman ◽  
J Kestner ◽  
M Ruddel
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Solid Phase ◽  
Equilibrium Dialysis ◽  
Free Fraction ◽  
Molar Ratio ◽  
Nonthyroidal Illness ◽  
Binding Rate ◽  
Number Of Patients ◽  
One Step

Abstract We examined the effect of endogenous free fatty acids (FFA) on the measurement of free thyroxin (FT4) by five different methodologies represented in 16 different assays in a large number of patients with nonthyroidal illness (NTI). Some, but not all, one-step (analog) FT4 RIAs negatively correlated with FFA concentration. All two-step FT4 RIAs, equilibrium dialysis FT4, and the dialyzable (free) fraction of T4 positively correlated. In contrast, a binding-rate-based FT4 RIA, FT4 indices based on T3 macroaggregated albumin uptake, and T4/TBG ratios did not correlate. We also analyzed the FT4-FFA relationship with a second, more sensitive approach by correlating test results with FFA/albumin molar ratio as an estimate of the "excess" (nonalbumin bound) FFA. We found that all FT4 RIAs, equilibrium dialysis FT4, FT4 indices based on T3 uptake, the dialyzable fraction of labeled T4 in equilibrium dialysis, the fraction of labeled T4 bound to solid phase antibody in the binding-rate-based RIA, and T3 uptake correlated with the FFA/albumin molar ratio. This FFA dependency was comparable among all the various techniques and was relatively small. Thus, increases or decreases in FT4 results due to varying FFA (and albumin) concentrations are highly likely with most currently available methods (only the T4/TBG ratio did not reveal FFA-dependency), but the magnitude of changes varies with the "excess" FFA.

Direct and indirect techniques for free thyroxin compared in patients with nonthyroidal illness. III. Analysis of interference variables by stepwise regression

1990 ◽  
Vol 36 (4) ◽  
pp. 645-650 ◽  
Author(s):  
G Csako ◽  
M H Zweig ◽  
M Ruddel ◽  
J Glickman ◽  
J Kestner
Keyword(s):  
Stepwise Regression ◽  
Equilibrium Dialysis ◽  
Negative Relationship ◽  
Molar Ratio ◽  
Test Results ◽  
Nonthyroidal Illness ◽  
Reverse T3 ◽  
Backward Elimination ◽  
One Step ◽  
Key Variables

Abstract We applied stepwise regression for multivariate analysis of data for free thyroxin (FT4) in serum and for other laboratory tests of thyroid function in patients with nonthyroidal illness. Using the maximum R2 improvement and backward elimination methods to test five variables [prealbumin, albumin, T4-binding globulin (TBG), free fatty acids (FFA), and FFA/albumin molar ratio], we found that the variables with the greatest predictive power clustered according to the methodology of FT4 measurement. Thus, we best predicted the FT4 results obtained by 16 techniques as follows: FT4 measured by one-step (analog) RIAs, with albumin; FT4 determined by two-step (sequential) RIAs, with FFA or FFA/albumin molar ratio; FT4 estimated by a binding-rate-based RIA or conceptually related FT4 indices [based on triiodothyronine (T3) uptake], with TBG; FT4 measured by equilibrium dialysis, with TBG and FFA/albumin molar ratio; and T4/TBG ratios, with either none or prealbumin and albumin. We could very highly (P less than 0.001) predict total T4 and T3 by considering TBG, and total T3 also by considering prealbumin and albumin, whereas reverse T3 was predictable with prealbumin only (negative relationship). We found comparatively weak associations between thyrotropin (TSH) and albumin or TBG. In clinical practice, abnormalities in key variables should call attention to possible effects of these variables on FT4 and other thyroid-test results and thus to the need for appropriate correction or alternative testing.

Direct and indirect techniques for free thyroxin compared in patients with nonthyroidal illness. II. Effect of prealbumin, albumin, and thyroxin-binding globulin.

1989 ◽  
Vol 35 (8) ◽  
pp. 1655-1662 ◽  
Author(s):  
G Csako ◽  
M H Zweig ◽  
J Glickman ◽  
M Ruddel ◽  
J Kestner
Keyword(s):  
Binding Proteins ◽  
Equilibrium Dialysis ◽  
Positive Association ◽  
Blood Collection ◽  
Free T4 ◽  
Nonthyroidal Illness ◽  
Positive Correlation ◽  
Binding Rate ◽  
One Step ◽  
Seriously Ill

Abstract We studied the correlation of thyroxin (T4)-binding proteins with the apparent free T4 (FT4) in 101 patients with nonthyroidal illness (NTI). Most patients (95%) were seriously ill at the time of blood collection. Concentrations of T4-binding prealbumin (transthyretin), albumin, and T4-binding globulin (TBG) often were low in the sera of these patients. Albumin was the most frequently subnormal, TBG the least. FT4 in serum was determined by five methods represented in 16 different assays. With few exceptions, analog (one-step) FT4 RIAs--both the binding-rate-based RIA and the related FT4 indices (calculated from triiodothyronine-macroaggregated albumin uptake and total T4)--and T4/TBG ratios correlated positively and usually highly significantly (P less than 0.01) with concentrations of prealbumin, albumin, and TBG. Equilibrium dialysis values for FT4 did not correlate with prealbumin concentrations but showed a weakly (P less than 0.03) positive association with albumin and a highly significant (P less than 0.002) positive correlation with TBG. Of the three two-step FT4 RIAs tested, the only statistically significant but weakly (P less than 0.02) positive correlation with T4-binding proteins was between Spiria FT4 and TBG. Thus, in these NTI patients, FT4 estimates vary with methodology and, to a lesser extent, with the particular assay used. The results from two-step FT4 RIAs are least associated with binding protein concentrations.

Binding of labeled thyroxin analog to serum proteins evaluated after radioimmunoassay of free thyroxin.

1989 ◽  
Vol 35 (3) ◽  
pp. 475-477 ◽  
Author(s):  
G Arevalo
Keyword(s):  
Serum Proteins ◽  
Equilibrium Dialysis ◽  
Normal Serum ◽  
Thyroid Status ◽  
Nonthyroidal Illness ◽  
Serum Pool ◽  
Normal Individuals ◽  
Ambulatory Patients ◽  
One Step

Abstract In ambulatory patients, assay of free thyroxin (FT4) in serum correlates well with thyroid status and with results obtained by equilibrium dialysis. The validity of FT4 results has been questioned mainly in euthyroid patients with altered concentrations of thyroid hormone-binding proteins, as in nonthyroidal illness, hereditary analbuminemia, familial dysalbuminemic hyperthyroxinemia (FDH), and the presence of iodothyronine-binding antibodies. I present here a study of the binding of [125I]T4-derivative to serum proteins in the supernate, which is ordinarily discarded after determination of FT4 by one-step radioimmunoassay with dextran-coated charcoal used to separate the free and bound fractions. The results are expressed as a ratio, with results for a normal serum pool as reference. The average ratio was high in hyperthyroid subjects, 1.26 (SD 0.12, n = 25), and in hypoalbuminemia, 1.20 (SD 0.10, n = 15), and low in FDH, 0.62 (SD 0.11, n = 9), and hypothyroid subjects, 0.90 (SD 0.06, n = 20). In normal individuals it was 0.98 (SD 0.05, n = 30). Determination of the analog-binding rate complements the FT4 result and allows for the recognition of cases with abnormal binding by serum proteins, without recourse to other tests recommended for thyroid-function studies.

Two new two-step immunoassays for free thyroxin evaluated: solid-phase radioimmunoassay and time-resolved fluoroimmunoassay

1990 ◽  
Vol 36 (7) ◽  
pp. 1355-1360 ◽  
Author(s):  
P Nuutila ◽  
P Koskinen ◽  
K Irjala ◽  
L Linko ◽  
H L Kaihola ◽  
...  
Keyword(s):  
Solid Phase ◽  
Equilibrium Dialysis ◽  
Late Pregnancy ◽  
Clinical State ◽  
Albumin Concentration ◽  
Time Resolved ◽  
One Step ◽  
Solid Phase Radioimmunoassay ◽  
Dialysis Method ◽  
Method R

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.

A Novel Route for Conversion of Free Fatty Acids in Acidic Oils to Methyl Esters by In-Situ Hydrolysis of Methyl Acetate

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Vijaya Lakshmi Ch ◽  
Uday Bhaskar R.V.S ◽  
Viswanath Kotra ◽  
Satyavathi Bankupalli
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Methyl Acetate ◽  
Edible Oils ◽  
Methyl Esters ◽  
Maximum Yield ◽  
Molar Ratio ◽  
Esterification Reaction ◽  
Higher Alcohol

Biodiesel from clean oils is comparatively easier than production from crude and non-edible oils. To achieve maximum yield of biodiesel, a two stage process is adopted in which non-edible oils are used as feed-stock: an acid catalyzed esterification of free fatty acids followed by base catalyzed transesterification. Presence of water formed during esterification reaction is detrimental to a viable transesterification process. In the present work, an alternate method for removal of water by in situ hydrolysis reaction of methyl acetate is introduced. The dehydration using methyl acetate during esterification has yielded good results as the soap formed during transesterification was minimal. The results indicated high conversion of triglycerides to methyl ester for lower oil to methanol ratio and at a lower temperature. For 1:3 molar ratio of oil to methanol, the conversion obtained was less than 90 percent and is equivalent to conversions with higher alcohol ratios during esterification in the absence of methyl acetate. These results are indicative of the fact that use of methyl acetate reduces the alcohol to oil ratio without affecting the conversions. Moreover, higher conversions are possible at lower temperatures in the presence of methyl acetate. It is further observed that the oils that are subjected to free fatty acid conversions in the presence of methyl acetate record very little soap formation during the transesterification reactions, thereby resulting in higher grade of biodiesel.

Remediation of Floating Vegetable Oil Spills by Sedimentation Followed by Anaerobic Biodegradation

2003 ◽  
Vol 2003 (1) ◽  
pp. 387-392 ◽  
Author(s):  
Zhengkai Li ◽  
Robert J. Downer ◽  
Brian A. Wrenn
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Vegetable Oil ◽  
Light Emission ◽  
Solid Phase ◽  
Sediment Toxicity ◽  
Ferric Hydroxide ◽  
Anaerobic Biodegradation ◽  
Sediment Concentration ◽  
Oil Biodegradation

ABSTRACT Floating vegetable oil can be effectively removed from the water surface and the water column as negatively buoyant oil-mineral aggregates by addition of a dense mineral, such as clay. In bench-scale experiments, it is possible to remove virtually all of the floating oil by addition of a sufficiently large dose of clay (>10 g clay/g oil). Once present in the sediments, vegetable oil can be completely transformed to harmless end products (e.g., carbon dioxide and methane) by naturally occurring microbial populations. Transient production of toxic intermediates (probably free fatty acids), measured as a reduction in sediment EC50 using the Microtox Solid-Phase Test (SPT), was observed during anaerobic biodegradation. The EC50 is the sediment concentration required to reduce light emission by bioluminescent bacteria by 50%. Addition of amorphous ferric hydroxide as an alternative electron acceptor stimulated the rate of vegetable oil biodegradation, but had no effect on the Microtox EC50. Alternative factors, including clay and calcium, were tested for their ability to reduce the transient toxicity by reducing the bioavailability of the free fatty acids. Calcium, and especially calcium plus clay, reduced the rate and extent of vegetable oil biodegradation but had no effect on the sediment toxicity as measured by the Microtox SPT. Only oil biodegradation significantly reduced the sediment toxicity.

scholarly journals Identification and Quantification of Fatty Acids in T. viridissima, C. biguttulus, and C. brunneus by GC-MS

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Alexander M. Wathne ◽  
Hanne Devle ◽  
Carl Fredrik Naess-Andresen ◽  
Dag Ekeberg
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Solid Phase Extraction ◽  
Free Fatty Acids ◽  
Dry Matter ◽  
Solid Phase ◽  
Neutral Lipids ◽  
Methyl Esters ◽  
Phase Extraction ◽  
Chorthippus Biguttulus

Fatty acid (FA) profiles of the species Tettigonia viridissima, Chorthippus biguttulus, and Chorthippus brunneus were determined and quantitated. Extracted lipids were derivatized into FA methyl esters (FAMEs) prior to analysis by GC-MS. A total of 37 different FAs were identified in T. viridissima, yielding a total FA content of 10.4 g/100 g of dry matter. The contents of saturated FAs, monounsaturated FAs, and polyunsaturated FAs were 31.1, 35.9, and 33.0%, respectively. Lipids from T. viridissima were also fractioned into neutral lipids, free fatty acids, and polar lipids by offline solid phase extraction. For C. brunneus and C. biguttulus, 33 FAs were identified, yielding a total FA content of 6.14 g/100 g of dry matter. SFAs, MUFAs, and PUFAs, respectively, constituted 32.7, 25.1, and 42.1% of the total FA content. The contents of MUFAs, PUFAs, n-3 FAs, and n-6 FAs of each species, and the n-6/n-3 ratio, were subsequently discussed.

Observations on the Relationships between Plasma Free Fatty Acids, Ketones and Bicarbonate in Acute Hyperglycaemia

1997 ◽  
Vol 34 (3) ◽  
pp. 303-310
Author(s):  
D Fraser Davidson
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Plasma Glucose ◽  
Plasma Concentrations ◽  
Molar Ratio ◽  
Bicarbonate Concentration ◽  
Acute Hyperglycaemia ◽  
Initial Plasma ◽  
Plasma Ffa ◽  
The Relationship

Some of the initial biochemical findings, obtained from 141 randomly-selected cases of acute hyperglycaemia (admission plasma glucose >20 mmol/L) were examined. When viewed in terms of their initial plasma bicarbonate concentration, three groups were identifiable. Plasma concentrations of free fatty acids (FFA), acetone and the sum of 3-hydroxybutyrate (3OHB) and lactate were different between these groups. However, there were no differences in plasma glucose or lactate concentrations. It was further observed that the relationship between the plasma FFA/albumin molar ratio, and ketone concentration could be described by a rectangular hyperbola, and the initial anion gap was linearly related to the sum of the 3OHB and lactate concentrations.

Sign in / Sign up

Export Citation Format

Share Document