Search

Total (t), monomeric (m) and polymeric (p) immunoglobulin A (IgA) levels were simultaneously measured in mixed faecal material collected over three consecutive days using a modified one-dimensional immunoelectrophoretic assay, which is a precise and reproducible method, Faecal t-, m- and p-IgA levels were statistically higher in 32 diarrhoeic patients than in a group of 16 healthy subjects (respectively 2-2. 2-6 and 2 0 times the normal). The values were also significantly different (P<0.001) when results were expressed as output per day in order to estimate the secreting capacity of gut. Moreover, the m-IgA/t-IgA percentages were significantly higher in faeces from diarrhoeic patients (42.3%) than in normal faeces (26.5%). These results confirm the importance of faecal IgA determination in estimating the local production of the IgA in various gastrointestinal tract disorders. [ABSTRACT FROM AUTHOR]

Abstract Background Obesity is characterized by inflammation, caused by increase in proinflammatory cytokines, a key factor for the development of insulin resistance. SR141716A, a cannabinoid receptor 1 (CB1) antagonist, shows significant improvement in clinical status of obese/diabetic patients. Therefore, we studied the effect of SR141716A on human adipocyte inflammatory profile and differentiation. Methods Adipocytes were obtained from liposuction. Stromal vascular cells were extracted and differentiated into adipocytes. Media and cells were collected for secretory (ELISA) and expression analysis (qPCR). Triglyceride accumulation was observed using oil red-O staining. Cholesterol was assayed by a fluorometric method. 2-AG and anandamide were quantified using isotope dilution LC-MS. TLR-binding experiments have been conducted in HEK-Blue cells. Results In LPS-treated mature adipocytes, SR141716A was able to decrease the expression and secretion of TNF-a. This molecule has the same effect in LPS-induced IL-6 secretion, while IL-6 expression is not changed. Concerning MCP-1, the basal level is down-regulated by SR141716A, but not the LPS-induced level. This effect is not caused by a binding of the molecule to TLR4 (LPS receptor). Moreover, SR141716A restored adiponectin secretion to normal levels after LPS treatment. Lastly, no effect of SR141716A was detected on human pre-adipocyte differentiation, although the compound enhanced adiponectin gene expression, but not secretion, in differentiated pre-adipocytes. Conclusion We show for the first time that some clinical effects of SR141716A are probably directly related to its anti-inflammatory effect on mature adipocytes. This fact reinforces that adipose tissue is an important target in the development of tools to treat the metabolic syndrome.

Abstract Background The risk of cardiovascular disease is inversely correlated to level of plasma HDL-c. Moreover, reverse cholesterol transport (RCT) from peripheral tissues to the liver is the most widely accepted mechanism linked to the anti-atherosclerotic activity of HDL. The apolipoprotein A-I (apoA-I) and the ABC transporters play a key role in this process. Adipose tissue constitutes the body's largest pool of free cholesterol. The adipose cell could therefore be regarded as a key factor in cholesterol homeostasis. The present study investigates the capacity of primary cultures of mature human adipocytes to release cholesterol and explores the relationships between apoA-I, ABCA1, and apoE as well as the signaling pathways that could be potentially involved. Results We demonstrate that apoA-I induces a strong increase in cholesterol release and apoE secretion from adipocytes, whereas it has no transcriptional effect on ABCA1 or apoE genes. Furthermore, brefeldin A (BFA), an intracellular trafficking inhibitor, reduces basal cholesterol and apoE secretion, but does not modify induction by apoA-I. The use of statins also demonstrates that apoA-I stimulated cholesterol release is independent of HMG-CoA reductase activation. Conclusion Our work highlights the fact that adipose tissue, and particularly adipocytes, may largely contribute to RCT via a mechanism specifically regulated within these cells. This further supports the argument that adipose tissue must be regarded as a major factor in the development of cardiovascular diseases, in particular atherosclerosis.

Abstract Background The development of obesity has been linked to an inflammatory process, and the role of adipose tissue in the secretion of pro-inflammatory molecules such as IL-6 or TNFalpha has now been largely confirmed. Although TNFalpha secretion by adipose cells is probably induced, most notably by TLR ligands, the activation and secretion pathways of this cytokine are not yet entirely understood. Moreover, given that macrophagic infiltration is a characteristic of obesity, it is difficult to clearly establish the level of involvement of the different cellular types present within the adipose tissue during inflammation. Methods Primary cultures of human adipocytes and human peripheral blood mononuclear cells were used. Cells were treated with a pathogen-associated molecular pattern: LPS, with and without several kinase inhibitors. Western blot for p38 MAP Kinase was performed on cell lysates. TNFalpha mRNA was detected in cells by RT-PCR and TNFalpha protein was detected in supernatants by ELISA assays. Results We show for the first time that the production of TNFalpha in mature human adipocytes is mainly dependent upon two pathways: NFkappaB and p38 MAP Kinase. Moreover, we demonstrate that the PI3Kinase pathway is clearly involved in the first step of the LPS-pathway. Lastly, we show that adipocytes are able to secrete a large amount of TNFalpha compared to macrophages. Conclusion This study clearly demonstrates that the LPS induced activation pathway is an integral part of the inflammatory process linked to obesity, and that adipocytes are responsible for most of the secreted TNFalpha in inflamed adipose tissue, through TLR4 activation.

Objective: White adipose tissue (WAT) is now considered a defined tissue capable of interactions with other organ systems. WAT role in elevating the level of systemic chronic inflammation suggests that alterations in this tissue as the result of disease or environmental factors may influence the development and progression of various obesity-related pathologies. This study investigated WAT cell-specific responses to an organometal compound, trimethyltin (TMT), to determine possible contribution to induced inflammation., Methods: Human primary mature adipocytes and macrophage differentiated THP-1 cells were cultured in TMT presence and relative toxicities and different adipokine levels were determined. The inflammatory response was examined in TMT presence for primary cells from obese ob/ob mice WAT, and after TMT injection in ob/ob mice., Results: Both adipocytes and macrophages were resistant to cell death induced by TMT. However, adipocytes cultured in TMT presence showed increased expression of TNFα and IL-6, and modified leptin levels. In macrophage cultures, TMT also increased TNFα and IL-6, while MCP-1 and MIP-1α were decreased. In vivo, a single injection of TMT in ob/ob mice, elevated TNFα, MIP-1α and adiponectin in WAT., Conclusions: Elevation of the inflammatory related products can be induced by chemical exposure in adipocytes and macrophages, as well as murine WAT. These data suggest that numerous factors, including a systemic chemical exposure, can induce an inflammatory response from the WAT. Furthermore, when characterizing both chemical-induced toxicity and the progression of the chronic inflammation associated with elevated WAT content, such responses in this target tissue should be taken into consideration., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Background: The risk of cardiovascular disease is inversely correlated to level of plasma HDL-c. Moreover, reverse cholesterol transport (RCT) from peripheral tissues to the liver is the most widely accepted mechanism linked to the anti-atherosclerotic activity of HDL. The apolipoprotein A-I (apoA-I) and the ABC transporters play a key role in this process.Adipose tissue constitutes the body's largest pool of free cholesterol. The adipose cell could therefore be regarded as a key factor in cholesterol homeostasis. The present study investigates the capacity of primary cultures of mature human adipocytes to release cholesterol and explores the relationships between apoA-I, ABCA1, and apoE as well as the signaling pathways that could be potentially involved., Results: We demonstrate that apoA-I induces a strong increase in cholesterol release and apoE secretion from adipocytes, whereas it has no transcriptional effect on ABCA1 or apoE genes. Furthermore, brefeldin A (BFA), an intracellular trafficking inhibitor, reduces basal cholesterol and apoE secretion, but does not modify induction by apoA-I. The use of statins also demonstrates that apoA-I stimulated cholesterol release is independent of HMG-CoA reductase activation., Conclusion: Our work highlights the fact that adipose tissue, and particularly adipocytes, may largely contribute to RCT via a mechanism specifically regulated within these cells. This further supports the argument that adipose tissue must be regarded as a major factor in the development of cardiovascular diseases, in particular atherosclerosis.

Alphaviruses, including Chikungunya virus (CHIKV), produce a transient illness in humans, but severe forms leading to chronic incapacitating arthralgia/arthritis have been reported by mechanisms largely ill-characterized. The pathogenesis of CHIKV was addressed in a prospective cohort study of 49 hospitalized patients from Reunion Island subsequently categorized into two distinct groups at 12 mo postinfection. Comprehensive analyses of the clinical and immunological parameters throughout the disease course were analyzed in either the "recovered" or the "chronic" groups to identify prognostic markers of arthritis-like pathology after CHIKV disease. We found that the chronic group consisted mainly of more elderly patients (>60 y) and with much higher viral loads (up to 10(10) viruses per milliliter of blood) during the acute phase. Remarkably, a rapid innate immune antiviral response was demonstrated by robust dendritic/NK/CD4/CD8 cell activation and accompanied by a rather weak Th1/Th2 cytokine response in both groups. Interestingly, the antiviral immune response witnessed by high levels of IFN-alpha mRNA in PBMCs and circulating IL-12 persisted for months only in the chronic group. CHIKV (RNA and proteins) was found in perivascular synovial macrophages in one chronic patient 18 mo postinfection surrounded by infiltrating NK and T cells (CD4(++) but rare cytotoxic CD8). Fibroblast hyperplasia, strong angiogenesis, tissue lesions given the high levels of matrix metalloproteinase 2, and acute cell death [high cleaved poly(ADP-ribose) polymerase staining] were observed in the injured synovial tissue. These observed cellular and molecular events may contribute to chronic arthralgia/arthritis targeted by methotrexate used empirically for effective treatment but with immunosuppressive function in a context of viral persistence.

Background: The development of obesity has been linked to an inflammatory process, and the role of adipose tissue in the secretion of pro-inflammatory molecules such as IL-6 or TNFalpha has now been largely confirmed. Although TNFalpha secretion by adipose cells is probably induced, most notably by TLR ligands, the activation and secretion pathways of this cytokine are not yet entirely understood. Moreover, given that macrophagic infiltration is a characteristic of obesity, it is difficult to clearly establish the level of involvement of the different cellular types present within the adipose tissue during inflammation., Methods: Primary cultures of human adipocytes and human peripheral blood mononuclear cells were used. Cells were treated with a pathogen-associated molecular pattern: LPS, with and without several kinase inhibitors. Western blot for p38 MAP Kinase was performed on cell lysates. TNFalpha mRNA was detected in cells by RT-PCR and TNFalpha protein was detected in supernatants by ELISA assays., Results: WE SHOW FOR THE FIRST TIME THAT THE PRODUCTION OF TNFALPHA IN MATURE HUMAN ADIPOCYTES IS MAINLY DEPENDENT UPON TWO PATHWAYS: NFkappaB and p38 MAP Kinase. Moreover, we demonstrate that the PI3Kinase pathway is clearly involved in the first step of the LPS-pathway. Lastly, we show that adipocytes are able to secrete a large amount of TNFalpha compared to macrophages., Conclusion: This study clearly demonstrates that the LPS induced activation pathway is an integral part of the inflammatory process linked to obesity, and that adipocytes are responsible for most of the secreted TNFalpha in inflamed adipose tissue, through TLR4 activation.

Oxidative stress and protein modifications are frequently observed in numerous disease states. Albumin, the major circulating protein in blood, can undergo increased glycoxidation in diabetes. Protein glycoxidation can lead to the formation of advanced glycoxidation end products, which induce various deleterious effects on cells. Herein, we report the effect of glucose or methylglyoxal-induced oxidative modifications on BSA or HSA protein structures and on THP1 monocyte physiology. The occurrence of oxidative modifications was found to be enhanced in glycoxidized BSA and HSA, after determination of their free thiol group content, relative electrophoretic migration, carbonyl content, and antioxidant activities. Cells treated with glycoxidized albumin exhibited an overgeneration of intracellular reactive oxygen species, impairments in proteasomal activities, enhancements in RAGE expression, and an accumulation of carbonylated proteins. These novel observations made in the presence of a range of modified BSA and HSA facilitate the comparison of the glycoxidation extent of albumin with the oxidative stress induced in cultured monocytes. Finally, this study reconfirms the influence of experimental conditions in which AGEs are generated and the concentration levels in experiments designed to mimic pathological conditions.

Surgical wound blood which is ched through drains after total knee replacement surgery with a tourniquet may be returned to the patient using special collecting devices. This study aimed to compare two systems, Orth-Evac and Solcotrans Plus an to assess the safety of the reinfusion of non washed blood cells. It included 30 patients scheduled for total knee replacement surgery, free from tumoral or coagulation disease and allocated randomly in three groups of 10 each: the Orth-Evac group (OGr), the Solcotrans Plus group (SGr) and the Control group (CGr). The devices, not containing an anticoagulant, were connected to the deep suction drains in the operating room, after skin closure and before the tourniquet removal. The salvaged blood was reinfused in the subsequent six hours via a 40 microns filter. The volume of collected blood was measured and homologous blood was added as required, to maintain a hematocrit of 30%. A blood sample was obtained the day before surgery (D - 1), before reinfusion (D0), two hours later (D + 2h), one day later (D + 1), and from the collecting device before reinfusion. The statistical analysis used the Kruskal-Wallis test and Steel-Dwass procedure to confirm the difference between two groups. The three groups did not differ in age, weight, height and gender. The volume of salvaged and autotransfused blood was 925 +/- 156 mL in OGr and 605 +/- 178 mL in SGr respectively, transfusion of homologous blood was required in two patients of OGr, four of SGr and six of CGr. At D + 1, the hematocrit was comparable in all groups (OGr = 28%, SGr = 28.2% and CGr = 28.5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Added to human serum in vitro, RU 41740, an immunomodulating agent extracted from Klebsiella pneumoniae, binds selectively to lipoproteins containing apolipoprotein B (low-density lipoproteins and very-low-density lipoproteins, VLDL) and, at higher concentrations, to lipoproteins containing apolipoprotein A (high-density lipoproteins). The fact that lipoproteins modulate polymorphonuclear neutrophil (PMN) functions led us to suspect that the VLDL-RU 41740 complex might affect PMN functions. In this study, the effect of this complex on PMN superoxide generation was measured in the presence and absence of the classical stimulants formyl-methionyl-leucyl-phenylalanine and phorbol myristate acetate. The VLDL-RU 41740 complex enhanced the stimulating effect of VLDL on quiescent PMN, but not following stimulation with formyl-methionyl-leucyl-phenylalanine. In contrast, it partially counteracted the inhibiting effect exerted by VLDL alone on phorbol myristate acetate stimulation. Such a complex might be formed in vivo during RU 41740 therapy and constitute an important feature in the immunostimulating properties of the drug.

Despite continuous monitoring progress, septic shock remains the main cause of death in Intensive Care Units. Septic stress triggers a complex array of biological modifications resulting in an acquired disease of intermediary metabolism whose main characteristic is an inefficient cellular use of glucidic, lipidic and protidic substrates together with oxygen. The purpose of this review is to present metabolic disturbances observed during sepsis and septic shock.

The serum phospholipids determination by an automatic enzymatic method (AEM) is suggested in this study. A comparison was made between the classical chemical method, the manual enzymatic method (MEM) and the AEM one. 100 serum samples were tested in this experiment and the correlation coefficient between these methods was found to be acceptable. The result indicates a good precision and a negligible contamination. The calibration curve is linear to 5 mmol/l. Triglyceride and cholesterol concentrations, glucose and high concentrated uric acid presence do not interfere on the value measured. However, the haemolysis and a large quantity of bilirubin in sera tend to induce a variation in the phospholipids determination.

The concentrations of estrogens (E) and human placental lactogen (HLP) are estimated in sera by radio immuno-assay (RIA) and enzyme-immuno-assay (EIA). Statistical data indicate mean intra-assay variation coefficients of 7% and 12% for E and HLP tests, respectively. The correlation coefficient (RIA/EIA) are found higher than 0,9% for both hormonal assays. The dilution curves obtained by RIA and EIA are similar. However, Student'test gives a significant difference for E determination. In fact, total E and E 3 only are measured by EIA and RIA, respectively. In most cases biological interferences are negligible except for HLP in presence of higher protein or haemoglobin levels. RIA and EIA are performed to study serum HLP and E levels throughout normal pregnancies. Results allow to use EIA for HLP and E evaluations in pregnancy-monitoring.

A simple automated assay was described for the determination of serum amylase using a chromogenic substrate. The reaction was stopped by filtration across a cellulose nitrate membrane. The analytic parameters of this method were studied. Repeatability, reproducibility and precision were convenient. The calibration curve was linear up to 850 U/I. An excellent correlation was obtained after comparison with the manual method (Phadebas amylase test). The effects of haemolysis and very high ascorbic concentrations of bilirubin, glucose, uric acid and ascorbic acid were negligible on the value measured. The serum turbidity was alone to induce a variation by excess.

The French Society of Rheumatology national study of reflex dystrophy revealed a serum glucose greater than 1.20 g/l in 9.09 p. cent of cases, a serum uric acid greater than 70 mg/l in 25 p. cent of men and greater than 60 mg/l in 14 p. cent of women. Serum cholesterol was normal in males, but higher than the mean + 2 sigma in 23 p. cent of females. Serum triglycerides were higher than m + 2 sigma in 55 p. cent of men and 56 p. cent of women. From a group of 80 patients, 54 (67.5 p. cent) had at least one of the three metabolic abnormalities and 49 (61.25 p. cent) were hypertriglyceridaemic. This hypertriglyceridaemia is the most frequent abnormality found. When hyperglycaemia or hyperuricaemia are present it is almost always in association with hypertriglyceridaemia. Hypertriglyceridaemia is more common in algoneurodystrophy of the lower limbs (54/78, 69 p. cent) than in algoneurodystrophy of the upper limbs (5/22, 22.7 p. cent). Algoneurodystrophy is more often primary, when it occurs in the lower limbs and post-traumatic when it occurs in the upper limbs. A prospective study comparing several parameters of lipid metabolism in 24 patients with algoneurodystrophy and 15 matched controls showed a significant drop in the HDL Chol/HDL P1 ratio and in the DHL - HDL Chol/TG ratio in patients with algoneurodystrophy. Serum insulin was comparable in the 2 groups. Lecithin cholesterol acyl transferase (LCAT), SGOT, SGPT and GGT were normal. The essential role of hypertriglyceridaemia in the genesis of the characteristic bony lesions of algoneurodystrophy is discussed.

Propranolol binding to human alpha 1-acid glycoprotein (AAG) delipidated by two methods is described. Commercial AAG (99% pure) was either precipitated by ethanol-acetone and then washed by ether, or it was precipitated by ethanol. Binding capacity was quantified by the product n x Ka where n denotes the number of binding sites and Ka the association constant (M-1). Propranolol binding to nondelipidated AAG (n x Ka = 0.113 +/- 0.013 microM-1) was clearly increased after precipitation by ethanol-acetone (n x Ka = 0.386 +/- 0.109 microM-1) or precipitation by ethanol (n x Ka = 0.312 +/- 0.096 microM-1). Binding capacity potentiation cannot be due to modification of AAG microheterogeneity forms, as two-dimensional gel electrophoresis pattern of AAG in presence of concanavalin A was not altered after both methods. Recombination of precipitated AAGs with supernatant dry residue resulted in the abrogation of observed potentiation. Moreover, addition of a polar lipid, linoleic acid, (from 30 to 300 microM) strongly inhibited propranolol binding. These results indicated that glycoprotein precipitation by ethanol provided a simple method to further study binding inhibitors associated with isolated AAG.

In this study we compare various methods for h;igh-density-lipoprotein cholesterol quantitation: ultracentrifugation; electrophoresis either on cellulose acetate or on agarose gel; precipitation methods with polyanions-bivalent cations; adsorption procedure using concanavalin A (Con A). quantification by electrophoresis is slow and not precise. Except heparin-Mn++ and dextran (MM 5 X 10(5) and 2 X 10(6)) - CaCl2 procedures, precipitation and Con A methods own a good repeatability (VC 2%) and give a linear response after VLDL or LDL-VLDL addition to tested sera. Regression analysis of the data obtained using these methods in pairs demonstrate a correct accuracy (r > 0.95). The Student t-test shows that the usual values must be evaluated for each method. We suggest to use either phosphotungstate - Mg++ or Con A procedure as method for HDL cholesterol quantitation.

The present work studies lipid metabolism in patients with algodystrophy (AD). A correct positive correlation (r = 0.75) between the triglyceride levels and low density lipoprotein (LDL)/very low density lipoprotein (VLDL) ratio and the VLDL increase observed by gel disk electrophoresis confirm that a type IV hyperlipoproteinemia is associated with AD. In contrast, the degree of high density lipoprotein (HDL) saturation in cholesterol (HDL-cholesterol/HDL-phospholipids) and the classical atherogenous index (cholesterol/HDL-cholesterol) were not modified. The decrease of plasma post-heparin lipolytic activities (PHLA) was not significant but further studies should be performed to correlate PHLA with a reduced activity of the adipose tissue lipoprotein lipase.

The French Society of Rheumatology national study of reflex dystrophy revealed a serum glucose greater than 1.20 g/l in 9.09 p. cent of case, a serum uric acid greater than 70 mg/l in 25 p. cent of men and greater than 60 mg/l in 14 p. cent of women. Serum cholesterol was normal in male cases, but higher than the mean + 2 sigma in 23 p. cent of female cases. Serum triglycerides was higher than m + 2 sigma in 55 p. cent of men and 56 p. cent of women. From a group of 80 patients, 54 (67.5 p. cent) had at least one of the three metabolic abnormalities and 49 (61.25 p. cent) were hypertriglyceridaemic. This hypertriglyceridaemia is the most frequent abnormality found. When hyperglycaemia or hyperuricaemia are present it is almost always in association with hypertriglyceridaemia. Hypertriglyceridaemia is more common in algoneurodystrophy of the lower limbs (54/78, 69 p. cent) than in algoneurodystrophy of the upper limbs (5/22, 22.7 p. cent). Algoneurodystrophy is more often primary, when it occurs in the lower limbs and post-traumatic when it occurs in the upper limbs. A prospective study comparing several parameters of lipid metabolism between 24 patients with algoneurodystrophy and 15 matched controls showed a significant drop in the HDL Chol/HDL P1 ratio and in the DHL--HDL Chol/TG ratio in patients with algoneurodystrophy. Serum insulin was comparable in the 2 groups. Lecithin cholesterol acyl transferase (LCAT), SGOT, SGPT and GGT were normal. The essential role of hypertriglyceridaemia in the genesis of the characteristic bony lesions of algoneurodystrophy is discussed.

A study was carried out to assess the effects of oral sodium citrate on the pH and volume of gastric content in 52 unpremedicated women undergoing elective Caesarean section under general anaesthesia. The patients were randomly assigned to two groups: group T (n = 26) without antacids and group C (n = 26) receiving orally 30 ml of 0.3 M sodium citrate solution 5 min before induction of anaesthesia. After tracheal intubation, a size 18 double lumen naso-gastric tube was introduced. The gastric content was sampled 10 min (n = 52), 50 min (n = 52) and 80 min (n = 24) later. Before extubation, the stomach was completely emptied and the naso-gastric tube removed. On each sampling time, the pH was measured with a digital pHmeter; a search for biliary salts (pyloric reflux) was carried out with thin layer chromatography; the volume of the gastric content was measured using the phenol red dilution method. At 10 min, none patient in group C had a gastric pH less than 2.5, in the opposite to 92% of patients in the control group T. The alkalinizing effect of the citrate lasted throughout the evaluation time. The mean pH was respectively 5.3 +/- 1.07, 5.23 +/- 1.2 and 5.53 +/- 1.3 at 10, 50 and 80 min in group C (controls: 1.9 +/- 0.7; 2.49 +/- 1.3; 2.40 +/- 0.61). However, the citrate solution increased significantly the volume of the gastric content. It was respectively 51.1 +/- 29.9 ml, 79.15 +/- 70.9 ml and 32.9 +/- 22.1 ml; 29.6 +/- 28.5 ml; 26.6 +/- 10.9 ml).(ABSTRACT TRUNCATED AT 250 WORDS)

An entirely automatic method, without prior extraction, is described for the determination of total serum lipids by a nephelemetric method. The results are compared with those obtained by Canal's method. There is a good correlation between the two technics. With a similar concentration of lipid the respective quantities of cholesterol and triglyceride do not intervene in the flocculation. The respective influence of the bilirubin concentration, hemolysis, and the concentration and nature of the serum proteins is considered. This method should permit simultaneous autoanalysis of the three parameters of classical lipid investigation: total lipids, triglycerides and cholesterol.

We describe an automated procedure for determination of high-density-lipoprotein cholesterol in serum by use of heparin-MgCl2-albumin reagent. 'AutoAnalyzer' II equipment was used in which high-density lipoprotein was separated from precipitate containing very-low and low-density lipoproteins by filtering on-line across a cellulose acetate membrane. Cholesterol concentration was measured by the enzymic method of Allain. Good correlation was obtained using the automated method compared to the heparin-MgCl2-albumin (r=0.99) or sodium phosphotungstate-MgCl2 procedure (r=0.97). Contamination was minimal with a contamination coefficient lower than 2.5%. The method presented was linear (0 to 2.50 mmol/1) and could be applied to lipemic samples with a coefficient of variation better than 3%. This study showed thus that this new procedure was suitable for routine work with a good rate (60 samples/h) in almost any laboratory.