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Light chain multiple myeloma is a hematologic malignancy characterized by an excess of tumor plasma cells in the bone marrow and a monoclonal light chain in blood. It is generally diagnosed in patients aged 60-75 years old. Hypercalcemia, anemia, kidney failure, and bone pains are the main clinical and biological signs. Here is an atypical case report about a 30 year-old man who was diagnosed a light chain multiple myeloma. This patient had been suffering from back pain for 5 months. Osteolytic lesions were discovered on X-rays prescribed by the family practitioner. Admitted to the Emergency department, all blood tests showed results within the normal range. The serum protein electrophoresis was also normal. Only the urine analysis showed proteinuria. The urine immunofixation electrophoresis showed a massive κ light chain. The bone marrow aspiration cell count confirmed the myeloma diagnosis with an infiltration of dystrophic plasma cells. The patient was transferred to the hematology ward of Necker Hospital for treatment of light chain myeloma.

Les termes CO 2 total et bicarbonate sont souvent utilises comme synonymes pour les dosages plasmatiques. Quel que soit le principe des dosages realises actuellement sur les analyseurs de biochimie, le terme CO 2 total doit etre privilegie.

Results of catalytic activities of enzymes are highly dependent on the measurement procedures and on local conditions. Thus, only poorly marked improvement of interlaboratory comparability of results have been observed in clinical enzymology. To solve this problem, SFBC and IFCC have proposed to use "validated enzyme calibrators". Standardised operating procedures adapted to 37 C have been developed by IFCC for the most commonly used enzymes in clinical chemistry, and will be soon published. Reference materials which have been certified with these SOPs can be used as calibrators for a set of measurement methods which exhibit the same analytical specificity. Calibrators must be commutable, a property that must be checked experimentally. It is possible to produce stable and commutable materials for the calibration of a set of methods. Interest of this approach has been demonstrated for several enzymes. Results of two studies presented here show that the comparison of results to the upper limit of reference ranges does not improve the interlaboratory comparability of results in contrast to the calibration of different methods by a common calibrator which allowed to reach an interlaboratory CV close to 4% for ALT and gammaGT.

Biological tests are important for the diagnosis and the follow-up of viral chronic hepatitis. The viral hepatitis C is by far the most frequent. The etiologic diagnosis is based on serological or immunological tests which have good sensitivity and specificity, and may be completed by molecular biological methods. In contrast, the tests for the evaluation of the activity (necrosis and inflammation) and of the fibrosis are less informative than the histological study. The diagnosis and prognosis interpretation of the aminotransferases are well known, but other tests as alpha glutathione S-transferase or orosomucoid are also proposed for evaluation of the activity. Some parameters as PIIINP or hyaluronic acid may be useful in the diagnosis and follow-up of fibrogenesis, fibrosis and cirrhosis but some new molecules, as the metalloproteinases and their inhibitors, are presenting interesting future prospects. Biological tests also contribute to the diagnosis of an associated extra-hepatic pathology and of a possible hepatocellular carcinoma occurring on the cirrhotic liver.

Traditionally, low-density lipoprotein (LDL) are separated with respect to their size, density and apolipoprotein composition. Fractionation of LDL according to their electrical charge is also interesting as modified LDL have been implicated in the onset of atherosclerosis. This review discusses possible mechanisms underlying charge heterogeneity of human plasma LDL, such as oxidation, glycation, conjugation with aldehydes, carbamylation and changes in sialic acid content and protein composition.

Through their specific biological properties, vascular endothelial cells play a major role in maintaining the homeostasis of the cardiovascular system. The vascular endothelium participates actively in coagulation and fibrinolysis, contributes to regulating vascular tone, is involved in inflammation and immunological responses, produces several different stromal components, plays a crucial role in angiogenesis and wound-healing, and interacts with plasma lipoproteins. These physiological functions of endothelial cells are triggered by different endothelium derived mediators and are regulated by numerous environmental factors that can markedly modulate the functional state of these cells by affecting their biosynthetic capabilities, giving them different phenotypes in native, activated and injured states. Excessive endothelial activation leads to changes in endothelial cell gene expression, leading to what is referred to as a dysfunctional state. In this non-adaptative functional state, endothelial cells lose the ability to adjust, within the physiological range, some of their constitutive functions and express newly induced molecules, some of which act as proatherosclerotic factors. Activated endothelial cells thus participate actively in the pathogenesis of atherosclerosis.

The advent of liver transplantation and the availability of effective medical therapeutics have recently made possible treatments of chronic liver diseases. These improvements have evidenced new needs for evaluation of the treated patients. In this review, authors present new biochemical liver tests proposed for a better monitoring in the course of the disease, to assess the therapeutic response in clinical trials and to reduce the number of liver biopsies. The different aspects of this paper concern the evaluation of hepatic uptake and biliary elimination, cholestasis, jaundice, cellular injury, fibrosis and liver tumor.

Cryoglobulins are immunoglobulins that precipitate at low temperatures. They are easy to characterize by using sensitive techniques such as immunofixation and immunoblotting. Recently, hepatitis C virus (HCV) has been found to be associated with essential mixed cryoglobulinemia. The different frequencies reported might be explained by heterogeneity in patient subpopulations and advances in serologic tests. In addition to commercial kits to detect HCV antibodies, polymerase chain reaction (PCR) of HCV RNA can now be applied to serum or cryoprecipitates. The pathogenic role of hepatitis C virus is well known, but the precise mechanism remains to be determined.

The role of plasma LDL in atherogenesis is now well established. Cholesteryl ester accumulation within macrophages leads to foam cell formation, an early atherosclerotic process. In vitro, foam cell formation scarcely ever occurs in the presence of native LDL. Modification of these lipoproteins is necessary for their binding to macrophage scavenger receptors. In vitro modifications reported have involved chemical reactions, physical mechanisms, enzymatic reactions, cellular interactions and association with macromolecules. In vivo, they can occur by glycation or desialylation, smoking or by hemodynamic interactions. Alterations of the physicochemical properties of LDL are induced by oxidation and include an increase in their density and their net electronegative charge, changes in lecithin composition, polyunsaturated fatty acid peroxidation of lipids and apolipoprotein B100 degradation. Apolipoprotein B100 fragmentation leads to an impairment of uptake through LDL receptors, while uptake through macrophage scavenger receptors is enhanced. Modified LDL have also other particularities such as cytotoxicity, chemotactism for circulating monocytes, inhibition of resident macrophage mobility, vasoconstriction, perturbation of the arachidonic acid cascade, involvement in haemostasis and immune mechanisms. Hypotheses concerning the role of modified LDL, in particular oxidized LDL, in atherogenesis open new therapeutic prospects.