Beta-quantification

Indirect Methods. Indirect methods for measuring LDL cholesterol are based on measuring a number of lipid-related analytes followed by their use in calculating the LDL cholesterol content of a specimen. This includes the use of the Friedewald equation and the beta-quantification method. 

Density gradient ultracentrifugation is used to measure hpoprotein subclasses it is performed in a vertical rotor with measurement of cholesterol continuously in the fractions eluted from the gradient. Mathematical curve resolution derives the component lipoprotein profiles and allows calculation of their cholesterol concentrations. The method can determine concentrations of VLDL, IDL, LDL, Lp(a), and HDL cholesterol. LDL cholesterol subclasses can be expressed separately or combined to give a measurement similar to that provided by the Friedewald equation or beta-quantification. A disadvantage is that the procedure is technically demanding and requires instrumentation not usually available in clinical laboratories. 

None of the lipoprotein methods described in this section has been used widely enough to have been validated in independent studies to the same extent as have been the Friedewald and beta-quantification methods. In most cases, the identities of the lipoprotein contributing to the LDL cholesterol measurement have not been adequately established. Further evaluations should better define the relationships between these new methods and current reference and routine methods. 

Jialal I, Hirany SV, Devaraj S, Sherwood TA. Comparison of an immunoprecipitation method for direct measurement of LDL-cholesterol with beta-quantification (ultracentrifugation). Am J Clin Pathol 1995 104 76-81. 

Nikolai LN, McClure EL, MacLeod SL, Wong CS (2006) Stereoisomer quantification of the Beta-blocker drugs atenolol, metoprolol, and propranolol in wastewaters by chiral high-performance liquid chromatography-tandem mass spectrometry. J Chromatogr A 1131 103-109... 

Celander, M. and Forlin, L. (1992). Quantification of cytochrome P450 lAl and catalytic activities in liver microsomes of isosafiol-treated and beta-naphthoflavone-treated rainbow trout Oncorhynchus mykiss). Marine Environmental Research, 34 123-126. 

Specific detectors are also available for quantification of radiopharmaceuticals. These detectors use a position-sensitive proportional counter. These detectors are sensitive to the beta and gamma nuclides listed in Table 3.5. The detector analog output can also be represented as an analog curve. Various other detection procedures have also been used, such as flame ionization [66], mass spectrometry [27,67], and infrared (IR) [68,69]. 

Jensen, M Hartmann, T., Engvall, B et al. (2000) Quantification of Alzheimer amyloid beta peptides ending at residues 40 and 42 by novel ELISA systems. Mol. Med. 6, 291-302. 

Bohm, M., and Lohse, M. J. 1994. Quantification of beta-adrenoceptors and beta-adrenoceptor kinase on protein and mRNA levels in heart failure. Eur. Heart J. 15 30-34. 

Muller-Renaud, S.P., Dupont, D., and Delie, P. 2004. Quantification of beta-casein in milk and cheese using an optical immunosensor. J Agric Food Chem 52 659-664. 

Seubert P, Vigo-Pelfrey C, Esch F, Lee M, Dovey H, Davis D, Sinha S, Schlossmacher M, Whaley J, Swindlehurst C et al (1992) Isolation and quantification of soluble Alzheimer s beta-peptide from biological fluids. Nature 359 325-327 Shen J, Bronson RT, Chen DF, Xia W, Selkoe DJ, Tonegawa S (1997) Skeletal and CNS defects in PresenUin-1-deficient mice. Cell 89 629-639... 

Maurer, H.H., Tenberken, O., Kratzsch, C., Weber, A., Peters, F.T. Screening for library-assisted identification and fully validated quantification of 22 beta-blockers in blood plasma by liquid chromatography-mass spectrometry with atmospheric pressure chemical ionization. J. Chromatogr. A 1058, 169-181 (2004)... 

Fig. 4 Response of zebrafish facial nerve to tastants. a Normalized facial nerve response to tastants. The integrated neural responses were normalized to the response to 1 mM L-Ala. Each column represents the mean the standard error of at least three independent assays. Tastants 1 mM amino acids, 300 mM sucrose (Suer), 300 mM glucose (Glue), 1 mM betaine (Beta), 1 mM inosine monophosphate (IMP), 10 mM denatonium (Den), and 1 mM quinine HC1 (QHCl). b Dose-dependent response of facial nerves to L-Ala in the absence (squares n = 3) or presence of either 1 mM IMP (triangles n = 2) or 1 mM betaine (circles n = 2). Responses were normalized to the response to 1 mM L-Ala. Each point shows the mean the standard error (triangles and circles), c Quantification of the responses to the chemicals. Each amino acid was used at 0.1 mM in the absence (black bars) or presence of either 1 mM IMP (white bars) or 1 mM betaine (hatched bars). Responses were normalized to the mean response at 1 mM L-Ala. (Modified from Oike et al. 2007 with permission)...

Gamperl, A.K., M. Wilkinson and R.G. Boutilier. Beta-adrenoreceptors in the trout (Oncorhynchus mykiss) heart characterization, quantification, and effects of repeated catecholamine exposure. Gen. Comp. Endocrinol. 95 259-272, 1994. 

Levine III, H. (1999) Quantification of beta-sheet amyloid fibril structures with thioflavin T. Methods Enzymol, 309, 274-84. 

Bosin, T., Krogh S., and Mais, D., Indentification and quantification of 1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid and l-methyl-l,2,3,4-tetrahydro-beta-arboline-3-carboxylic acid in beer and wine, /. Agric. Food Chem., 34, 843, 1986. 

K Fujiwara, et al. Enzyme immunoassay for the quantification of mithramycin using beta-deuterium-galactosidase as a label. Cancer Res 46 1084, 1986. 

Bertolotto, A., Sala, A., Caldano, M., Capobianco, M., Malucchi, S., Mametto, F., and Gilli, F. (2007) Development and validation of a real time PCR based bioassay for quantification of neutralizing antibodies against human interferon beta. Journal of... 

Linear Analyzer. The linear analyzer was developed for the measurement of beta-emitting radionuclides and was introduced in 1980 by Berthold Analytical Instruments (Filthuth 1986). It operates as a position-sensing proportional counter, measuring a fixed number of channels along the length of the chromatographic plate. The system is equipped with analytical software for quantification. 

Kahn, S.E., Prigeon, R.L., McCulloch, D.K., Boyko, E.J., Bergman, R.N., Schwartz, M.W., Neifing, J.L., Ward, W.K., Beard, J.C., and Palmer, J.P. 1993. Quantification of the relationship between insulin sensitivity and beta-cell function in human subjects. Evidence for a hyperbolic function. Diabetes. 42 1663-1672. 

Identification and quantification of cis-ketoconazole impurity in tablets Heptakis-(2,3, 6-tri-0-methyl)-beta-cyclodextrin CE-MS [207]... 

Although there are many radioactivity detectors available, there has been very little development of analytical instruments or radiochemical sensors suitable for rapid and selective quantification of beta- and alpha-emitting radionuclides such as c, Sr, and TRU actinides in water or process streams. Current baseline analytical methods for these analytes are based on tedious manual radiochemical analysis methods performed in centralized laboratories. 

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