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Valutazione di un nuovo metodo omogeneo per la determinazione del colesterolo-LDL

Giampaolo Cattozzo*, Sergio Finazzi, Gian Vico Melzi d'Eril1
*Laboratorio di Analisi, Ospedale Filippo Del Ponte - A. O. Fondazione Macchi, Varese

Biochimica Clinica: 1999; 23(4): 205-209 [Article in italian]

ABSTRACT. We evaluated a new homogeneous method for the measurement of LDL-cholesterol without prior preparation. Imprecision fulfills the recommendations of the NCEP: within-run, between-days and overall imprecision (CV%) never exceeded 3.5 for low and high concentrations (100.2 and 177.3 mg/dL, respectively). When the method (y) was compared to the Friedewald method (samples with tryglicerides up to 400 mg/dL) the non-parametric linear regression equation was y = 0.98x + 3.6 mg/dL (n = 77; r = 0.9196; S_y/x = 19.3 mg/dL); when it was compared to an established homogeneous method (samples with tryglicerides up to 1010 mg/dL) the same equation was y = 1.09x + 6.7 mg/dL (n = 96; r = 0.9618; S_y/x = 14.4 mg/dL). The regression analysis of plasma (y) versus serum samples gave y = x - 3.0 mg/dL (n = 15; r = 0.9711; S_y/x = 8.2 mg/dL; p>0.05 according to Wilcoxon scores) for heparin-plasma samples, and y = 0.93x + 2.4 mg /dL (n = 20; r = 0.9756; S_y/x = 6.9 mg/dL; p<0.001) for EDTA-plasma samples. Furthermore, we compared postprandial (2 hours after a continental breakfast, about 300 kcal) vs fasting samples: the t-test showed no significant difference (p>0.05) between fasting and postprandial samples. We conclude that the evaluated method shows good precision, good agreement with values calculated with the Friedewald equation and good correlation with the established homogeneous method. It may be used for reliable LDL-cholesterol measurements also in serum samples with tryglicerides higher than 400 mg/dL, in heparin-plasma samples and in postprandial samples.

Clinical significance and advances in the measurement of LDL cholesterol

Mauro Panteghini
1° Laboratorio Analisi Chimico-Cliniche, Azienda Ospedaliera `Spedali Civili', Brescia, Italy

Biochimica Clinica: 1999; 23(4): 210-215 [Article in english]

ABSTRACT. The increase in low-density lipoprotein cholesterol (LDL-C) concentrations in plasma constitutes a major risk factor for the development of coronary artery disease. The relation between LDL-C and coronary disease has been established in many observational epidemiologic studies and in numerous clinical trials of lipid-lowering interventions. These trials have demonstrated conclusively that decreasing LDL-C decreases coronary disease morbidity and mortality, slows disease progression, and can even lead to regression of atherosclerotic lesions. The recent development of the direct homogeneous assays for LDL-C determination represents an important advance in laboratory testing, now providing a superior method for physicians to confidently diagnose, classify, and treat patients according to National and International guidelines. The medical community has eagerly awaited the availability of a direct test to measure LDL-C. It is hoped that the availability of such a test will encourage more physicians to screen, detect, and treat high concentrations of LDL-C in the population, thereby significantly reducing risk of coronary disease.

Medicina di laboratorio e doping

Giuseppe Lippi
Istituto di Chimica e Microscopia Clinica, Universitą degli Studi di Verona, Verona

Biochimica Clinica: 1999; 23(4):216-226 [Article in italian]

ABSTRACT. The worrying tendency towards the exasperation of the athletic performances represents the primary reason for the gradual diffusion of illegal doping methods and substances in sport. As the number of doping practices grows, so do the requirements for appropriate and reliable method of screening. However, inasmuch as a positive drug test might wreck, often irrevocably, image and carrier of professional athletes, the application of reliable tools for identiying unfairness appears crucial. Laboratory testing is a powerful weapon; nevertheless, preparation of the patient, collection and storage of the samples, selection and standardization of analytical techniques, accurate interpretation of results are pivotal aspects that, beside political implications, belong to the good laboratory practice and must be harmonized and respected. In this perspective, Laboratory Medicine must reassume its prominent role.

Prostasomes are Pluripotent and Well - Organized Organelles in Human Semen

Gunnar Ronquist
Department of Clinical Chemistry, University Hospital, Uppsala, Sweden

Biochimica Clinica: 1999; 23(4):227-232 [Article in english]

ABSTRACT. Prostasomes are submicron, membrane-surrounded organelles produced by the epithelial cells of the human prostate gland and are present in appreciable amounts in normal human semen. The prostasomes are ascribed many functional effects. They have an immunosuppressive capacity by inhibiting the lymphoproliferation and the phagocytosis of macrophages. The prostasomes also regulate the complement activation. They possess an antioxidant capacity. The prostasomes are also able to attach onto washed, prostasome-free spermatozoa and promote the forward motility of the sperm cells.

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