La X de las dislipemias / The "x" of dyslipemias

Los pacientes con colestasis hepática pueden presentar hipercolesterolemia secundaria, como consecuencia de la acumulación de la lipoproteína X (Lp-X); una forma anómala de LDL, considerada como el parámetro bioquímico más sensible y específico para el diagnóstico de colestasis intra o extrahepática. El objetivo de esta comunicación clínica es ilustrar esta asociación. Se trata de un varón de 54 años con hepatopatía colestásica severa que a su vez presenta una elevación progresiva de colesterol total y LDL con presencia de lipoproteína X. El colesterol total y LDL, descendieron progresivamente hasta normalizarse, coincidiendo con la mejoría de la función hepática, confiriendo un patrón de protección cardiovascular (AU)

Patients with cholestatic diseases can present secondary hypercholesterolemia, as a result of the accumulation of lipoprotein X (Lp-X); an abnormal LDL form, considered as the biochemical parameter more sensitive and specific for the diagnosis of cholestasis intra or extrahepatic cholestasis. The aim of this clinical comunication is to illustrate this association. A 54-year-old male with severe cholestatic liver disease wich in turn presents a progressive total cholesterol rise and LDL with presence of lipoprotein X. Total and LDL cholesterol were down to normal, also coinciding with the improvement of cholestatic liver disease conferring cardiovascular protection pattern (AU)

Pseudohyponatraemia in a patient with obstructive jaundice.

INTRODUCTION: Pseudohyponatraemia is uncommonly associated with severe hypercholesterolaemia. Severe hypercholesterolaemia encountered in obstructive jaundice due to an abnormal lipoprotein, lipoprotein X (LpX), may result in pseudohyponatraemia. CASE REPORT: We report a case of falsely low sodium measurements in a patient with severe hypercholesterolaemia due to obstructive liver disease. The pathophysiology, complications and analytical effects of LpX are briefly discussed. CONCLUSION: The possibility of pseudohyponatraemia should be considered in severely hypercholesterolaemic samples.

Clinical significance of serum high-molecular-mass alkaline phosphatase, alkaline phosphatase-lipoprotein-X complex, and intestinal variant alkaline phosphatase.

This paper is a study to identify the clinical significance of high-molecular-mass alkaline phosphatase (ALP:E:C..3.1.3.1.), ALP-lipoprotein-X complex (LP-X) and intestinal variant ALP. We used cellulose acetate and agarose gels and techniques including wheat germ lectin, cetavlon-diethyl ether, thermostatability, neuraminidase and L-phenylalanine to improve the electrophoretic separation of the alkaline phosphatase isoenzymes. Patients' serum samples were electrophoresed from a diverse group of individuals ill with cholestasis, neoplastic disease metastatic to the liver, hepatocellular carcinoma, cirrhosis, diabetes mellitus, and chronic renal disease. Agarose gels provided better separation of ALP isoenzymes than cellulose acetate gels. The results also indicated that high-molecular mass ALP is present in patient's serum in conditions associated with cholestasis especially caused by hepatic malignancy. High-molecular mass ALP was frequently found to co-exist with the liver isoenzyme and LP-XALP complex. The intestinal variant was identified in patients with malignancy, cirrhosis, chronic renal disease and diabetes mellitus. Intestinal ALP coexisted concomitantly with a variant intestinal ALP. Intestinal variant ALP is most likely composed of intestinal ALP attached to a cellular membrane-binding domain, or may be an artifact produced by neuraminidase incubation.

Biliary proteins.

The study of biliary proteins has grown enormously in the last 10 years. Although much has been recently learned about the nature, origin and hepatobiliary transport of these proteins, little is known of their function in bile or their effect on its physical state. This review will focus on description of the proteins and mechanisms by which they are secreted into bile.

Apolipoproteins and lipoproteins of human plasma: significance in health and in disease.

When DeLalla and Gofman (1954) presented their work "Ultracentrifugal Analysis of Serum Lipoproteins" more than 25 years ago, we were thinking about lipoproteins in terms of density fractions. In the 1970s the electrophoresis concept was pushed by Fredrickson and his colleagues (Fredrickson et al., 1967). There is no doubt that both these lipoprotein research centers have fertilized entire investigations in this field and still have a tremendous impact on our current knowledge. It was, however, not until 1966, when Gustafson, Alaupovic, and Furmann first described the presence of a third lipoprotein family, LpC, that researchers in this area became aware of the dominant role of apolipoproteins in the transport and metabolism of plasma lipids. Lipoprotein density fractions and electrophoretic classes in the mean time have not lost their importance; they still exist and the application of methods yielding those fractions is still going on in lipoprotein laboratories. Yet we need to recognize that the whole lipid transport system is far more complex than was believed some 10 or 20 years ago. Lipoprotein density fractions consist of varying numbers of families; some of them comigrate upon electrophoresis, and the protein moiety of them is mostly composed of nonidentical polypeptides. There are a number of inborn errors of metabolism, for example, ABL, Tangier disease, and enzyme defects, which have taught us a lot about the functions and interplay of the complex apolipoprotein system. In dyslipoproteinemia, abnormal lipoproteins occur in the plasma and apolipoproteins, which are hardly recognized in normal fasting plasma, suddenly become prominent. There still exist, however, apolipoproteins and lipoproteins, one of which certainly is Lp(a), whose function and biological significance remains completely unknown. The structure and the molecular arrangement of lipids and apolipoproteins within a lipoprotein particle has been the subject of intensive investigations, and almost every physicochemical method available has been applied to reveal the morphology of individual lipoproteins in closest detail. Lipoproteins and apolipoproteins have often also served as model substances for cell membranes. After the purification of individual apolipoproteins succeeded in many laboratories and specific antibodies were available, clinical chemists and epidemiologists became interested in this area of research. Apolipoprotein quantification currently is most prominent for the prediction of atherosclerotic risk in preventive medicine.(ABSTRACT TRUNCATED AT 400 WORDS)