Triglycerides measurement

Fig. 15. Comparison of a water suppressed muscle spectrum and a spectrum from yellow bone marrow containing almost pure fat (triglycerides). Measurement parameters STEAM sequence, TE=10 ms, TM=15 ms, TR = 2 s, 40 acq., VOI (11 X 11 X 20) mm. (a) Spectrum from TA muscle recorded after careful positioning of the VOI, avoiding inclusion of macroscopic fatty septa allows separation of extramyocellular (EMCL, broken lines) and intramyocellular lipid signals (IMCL, dotted lines) based on susceptibility differences. For this reason characteristic signals from fatty acids occur double. Signals of creatine (methyl, Crs, and methylene, Cr2) show triplet and doublet structure, respectively, due to dipolar coupling effects. Further signals of TMA (including carnitine and choline compartments), Taurine (Tau), esters, unsaturated fatty acids (-HC=CH-), and residual water are indicated, (b) Spectrum from yellow fatty bone marrow of the tibia with identical measuring parameters, but different amplitude scale.

E514 Earl, R.E., Studts, D.J. and Markin, R.S. (1989). Glycerol blanked triglyceride measurement on the Hitachi 705 chemistry analyzer. Clin. Chem. 35, 1072, Abstr. 34. 

Although triglyceride blanks can in most cases be ignored in clinical measurements, they can dramatically affect conclusions about method accuracy, important in cahbra-tion or in standardization of triglyceride measurements. For example, participation in the CDC standardization program requires use of a blanking method, several of which... 

Glycerol blanking of triglyceride measurements must be done in laboratories participating in the CDC Lipoprotein Standardization Program and is recommended for laboratories that specialize in assessment of lipid status, have large populations of hyperlipidemic subjects, or participate in clinical or basic research. 

Franzin M, Ferro C, Ceriotti F, Carobene A, Martini R, Guerra E. Optimization of a designated comparison method (DCM) for triglycerides measurement. Clin Chem Lab Med 1999 37 S260. 

Useful observables that are informative about the state of the liver include the level of glucose in the blood, the amount of the protein albumin in the blood (produced by the liver), the level of liver enzymes in the blood (these are normally found in the liver cells and only get into the blood in elevated levels when the liver cells are diseased and release the enzymes). The activity of the detoxifying enzymes (called cytochrome p450 enzymes) can also reflect the state of the liver. The quantity of triglycerides measured in the blood can reflect lipid metabolism by the liver cells. 

Klotzsch, S. G., and J. R. McNamara. 1990. Triglyceride measurements a review of methods and interferences. Clinical Chemistry 36 1605-1613. 

Gorin, E., and E. Shafrir Turnover of adipose tissue triglycerides measured by the rates of synthesis and release of triglyceride glycerol. Biochim. biophys. Acta (Amst.) 70,109 (1963). 

Seifried, B., Temelli, F. (2011). Viscosity and theological behaviour of carlxm dioxide-expanded fish oil triglycerides Measurement and modeling. Jourruil of Supercritical Fluids,... 

Potentiometry is another useful method for determining enzyme activity in cases where the reaction Hberates or consumes protons. This is the so-called pH-stat method. pH is kept constant by countertitration, and the amount of acid or base requited is measured. An example of the use of this method is the determination of Hpase activity. The enzyme hydroly2es triglycerides and the fatty acids formed are neutralized with NaOH. The rate of consumption of NaOH is a measure of the catalytic activity. 

If serum triglycerides are greater than 400 mg/dL (4.52 mmol/L), this formula becomes inaccurate and LDL cholesterol must be directly measured.3... 

Often you need to carry forward data to a specific time point due to holes or sparseness of data. The previous example on determining baseline cholesterol level provides an excellent context for this problem. Assume that you have several cholesterol readings of HDL, LDL, and triglycerides for patients before they take an experimental pill designed to reduce cholesterol levels. For each cholesterol parameter, you want the last observation carried forward so long as the measures occur within a five-day window before the pill is taken. Here are some sample data that illustrate the problem ... 

Olive oil was the original model lipid for partition studies, and was used by Overton in his pioneering research [518,524], It fell out of favor since the 1960s, over concerns about standardizing olive oil from different sources. At that time, octanol replaced olive oil as the standard for partition coefficient measurements. However, from time to time, literature articles on the use of olive oil appear. For example, Poulin et al. [264] were able to demonstrate that partition coefficients based on olive oil-water better predict the in vivo adipose-tissue distribution of drugs, compared to those from octanol-water. The correlation between in vivo log Kp (adipose tissue-plasma) and log (olive oil-water) was 0.98 (r2), compared to 0.11 (r2) in the case of octanol. Adipose tissue is white fat, composed mostly of triglycerides. The improved predictive performance of olive oil may be due to its triglyceride content. 

A fasting lipoprotein profile including total cholesterol, LDL, HDL, and triglycerides should be measured in all adults 20 years of age or older at least once every 5 years. 

Measurement of plasma cholesterol (which is about 3% lower than serum determinations), triglyceride, and HDL levels after a 12-hour or longer fast is important, because triglycerides may be elevated in nonfasted individuals total cholesterol is only modestly affected by fasting. 

Short-term evaluation of therapy for hyperlipidemia is based on response to diet and drug treatment as measured in the clinical laboratory by total cholesterol, LDL-C, HDL cholesterol, and triglycerides. 

Chiou chose glyceryl trioleate (triolein) as model lipid because of its similarity to triglycerides which are abundant in organisms [109], Triolein is also a bulk lipid and the good correlation with the bioconcentration factor is restricted to neutral compounds of moderate hydrophobicity. No attempts were made to measure partitioning of ionogenic compounds with the glyceryl trioleate-water partition system. 

Factors negatively affecting absorption of dietary fat may also be expected to negatively affect absorption of calcium. In the normal, healthy adult, dietary fat absorption is very efficient. However, such factors as level of dietary fat, fatty acid chain length, degree of fatty acid saturatedness, or triglyceride structure may have a measurable effect on calcium absorption under some circumstances. 

K38. Kronenberg, F., Lobenstanz, E.-M., Konig, P., Utermann, G., and Dieplinger, H., Effect of sample storage on the measurement of lipoprotein(a), apolipoproteins B and A-IV, total and high density lipoprotein cholesterol and triglycerides. J. Lipid Res. 35, 1318-11328 (1994). 

Fatty acids are clearly larger in size and show markedly slower diffusion velocity than the small water (or creatine) molecules which have been examined so far by diffusion weighted NMR spectroscopy. However, assessment of diffusion properties of lipids could be a key step for further experimental studies of skeletal muscle lipid metabolism. Diffusion properties of FFA and triglycerides are likely different due to differences in molecular weight. In addition, effects of temperature, chemical surroundings, and the mobility of small lipid droplets in the cytosol may also lead to measurable differences in the diffusion characteristics. 

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