ANA MARIA PITA LOTTENBERG
Projetos de Pesquisa
Unidades Organizacionais
LIM/10 - Laboratório de Lípides, Hospital das Clínicas, Faculdade de Medicina
2 resultados
Resultados de Busca
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- International descriptive and interventional survey for oxycholesterol determination by gas- and liquid-chromatographic methods(2018) LUETJOHANN, Dieter; BJORKHEM, Ingemar; FRIEDRICHS, Silvia; KERKSIEK, Anja; GEILENKEUSER, Wolf-Jochen; LOVGREN-SANDBLOM, Anita; ANSORENA, Diana; ASTIASARAN, Iciar; BAILA-RUEDA, Lucia; BARRIUSO, Blanca; BRETILLON, Lionell; BROWNE, Richard W.; CACCIA, Claudio; CENARRO, Ana; CRICK, Peter J.; FAULER, Guenter; GARCIA-LLATAS, Guadalupe; GRIFFITHS, William J.; IULIANO, Luigi; LAGARDA, Maria Jesus; LEONI, Valerio; LOTTENBERG, Ana Maria; MATYSIK, Silke; MCDONALD, Jeff; RIDEOUT, Todd C.; SCHMITZ, Gerd; NUNES, Valeria Sutti; WANG, Yuqin; ZERBINATI, Chiara; DICZFALUSY, Ulf; SCHOETT, Hans-FriederIncreasing numbers of laboratories develop new methods based on gas-liquid and high-performance liquid chromatography to determine serum concentrations of oxygenated cholesterol metabolites such as 7 alpha-, 24(S)-, and 27-hydroxycholesterol. We initiated a first international descriptive oxycholesterol (OCS) survey in 2013 and a second interventional survey 2014 in order to compare levels of OCS reported by different laboratories and to define possible sources of analytical errors. In 2013 a set of two lyophilized serum pools (A and B) was sent to nine laboratories in different countries for OCS measurement utilizing their own standard stock solutions. In 2014 eleven laboratories were requested to determine OCS concentrations in lyophilized pooled sera (C and D) utilizing the same provided standard stock solutions of OCS. The participating laboratories submitted results obtained after capillary gas-liquid chromatography-mass selective detection with either epicoprostanol or deuterium labelled sterols as internal standards and high-performance liquid chromatography with mass selective detection and deuterated OCS as internal standard. Each participant received a clear overview of the results in form of Youden-Plots and basic statistical evaluation in its used unit. The coefficients of variation of the concentrations obtained by all laboratories using their individual methods were 58.5-73.3% (survey 1), 56.8-60.3% (survey 2); 36.2-35.8% (survey 1), 56.6-59.8, (survey 2); 61.1-197.7% (survey 1), 47.2-74.2% (survey 2) for 24(S)-, 27-, and 7 alpha-hydroxycholesterol, respectively. We are surprised by the very great differences between the laboratories, even under conditions when the same standards were used. The values of OCS's must be evaluated in relation to the analytical technique used, the efficiency of the ample separation and the nature of the internal standard used. Quantification of the calibration solution and inappropriate internal standards could be identified as major causes for the high variance in the reported results from the different laboratories. A harmonisation of analytical standard methods is highly needed. (C) 2018 Published by Elsevier B.V.
- First international descriptive and interventional survey for cholesterol and non-cholesterol sterol determination by gas- and liquid-chromatography-Urgent need for harmonisation of analytical methods(2019) LUETJOHANN, Dieter; BJORKHEM, Ingemar; FRIEDRICHS, Silvia; KERKSIEK, Anja; LOVGREN-SANDBLOM, Anita; GEILENKEUSER, Wolf-Jochen; AHRENDS, Robert; ANDRADE, Isabel; ANSORENA, Diana; ASTIASARAN, Iciar; BAILA-RUEDA, Lucia; BARRIUSO, Bianca; BECKER, Susen; BRETILLON, Lionel; BROWNE, Richard W.; CACCIA, Claudio; CEGLAREK, Uta H.; CENARRO, Ana; CRICK, Peter J.; FAULER, Guenter; GARCIA-LLATAS, Guadalupe; GRAY, Robert; GRIFFITHS, William J.; GYLLING, Helena; HARDING, Scott; HELMSCHRODT, Christin; IULIANO, Luigi; JANSSEN, Hans-Gerd; JONES, Peter; KAIPIAINEN, Leena; KANNENBERG, Frank; LAGARDA, Maria Jesus; LEONI, Valerio; LOTTENBERG, Ana Maria; MACKAY, Dylan S.; MATYSIK, Silke; MCDONALD, Jeff; MENENDEZ-CARRENO, Maria; MYRIE, Semone B.; NUNES, Valeria Sutti; OSTLUND, Richard E.; POLISECKI, Eliana; RAMOS, Fernando; RIDEOUT, Todd C.; SCHAEFER, Ernst J.; SCHMITZ, Gerd; WANG, Yuqin; ZERBINATI, Chiara; DICZFALUSY, Ulf; SCHOETT, Hans-FriederSerum concentrations of lathosterol, the plant sterols campesterol and sitosterol and the cholesterol metabolite 5 alpha-cholestanol are widely used as surrogate markers of cholesterol synthesis and absorption, respectively. Increasing numbers of laboratories utilize a broad spectrum of well-established and recently developed methods for the determination of cholesterol and non-cholesterol sterols (NCS). In order to evaluate the quality of these measurements and to identify possible sources of analytical errors our group initiated the first international survey for cholesterol and NCS. The cholesterol and NCS survey was structured as a two-part survey which took place in the years 2013 and 2014. The first survey part was designed as descriptive, providing information about the variation of reported results from different laboratories. A set of two lyophilized pooled sera (A and B) was sent to twenty laboratories specialized in chromatographic lipid analysis. The different sterols were quantified either by gas chromatography-flame ionization detection, gas chromatography- or liquid chromatography-mass selective detection. The participants were requested to determine cholesterol and NCS concentrations in the provided samples as part of their normal laboratory routine. The second part was designed as interventional survey. Twenty-two laboratories agreed to participate and received again two different lyophilized pooled sera (C and D). In contrast to the first international survey, each participant received standard stock solutions with defined concentrations of cholesterol and NCS. The participants were requested to use diluted calibration solutions from the provided standard stock solutions for quantification of cholesterol and NCS. In both surveys, each laboratory used its own internal standard (5 alpha-cholestane, epicoprostanol or deuterium labelled sterols). Main outcome of the survey was, that unacceptably high interlaboratory variations for cholesterol and NCS concentrations are reported, even when the individual laboratories used the same calibration material. We discuss different sources of errors and recommend all laboratories analysing cholesterol and NCS to participate in regular quality control programs.