Improved quality of samples and laboratory turnaround time using 3.5 mL low vacuum BD Vacutainer® Barricor tubes in the emergency department

Background

Centrifugation is a consuming time step which participates to increase the turnaround time (TAT) in laboratories, likewise hemolysis sample that needs a re-sampling could delay management of patients. Recently, it has been postulated that BD Barricor™ tube could allow to decrease the centrifugation time and prevent hemolysis, two key feature to ensure high-quality results.

Aim of the study was to evaluate the impact of replacing 4 mL BD vacutainer heparin lithium tube by low vacuum 3.5 mL BD vacutainer Barricor™ tube in an emergency department (ED) on hemolysis rate and TAT.

Methods

Data of hemolysis index (HI) and TAT were compared between the first period of 15 days using 4 mL BD vacutainer heparin lithium tubes with 15 min at 2000xg as centrifugation setting and a second period of 15 days using BD vacutainer Barricor™ tube centrifuged 3 min at 4000xg.

Results

A significantly reduced time duration between reception of sample and available results in informatics lab system was observed with the reduction time of centrifugation allowed by use of Barricor™ tube compared to regular heparin lithium tubes (p < 0.001). A significative decrease in hemolysis rate also occurred in the second period as samples with HI < 10 reached from 52.5% in the first period to 68.5% (p < 0.001) in the second.

Conclusion

Low vacuum Barricor^TM tubes allowing a higher speed of centrifugation improve lab TAT without impairment of sample quality as a significant reduction of hemolysis was observed, a double advantage which is of particular interest for ED.

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Improving turnaround time and quality samples is a challenge for all laboratories.

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Hemolyzed samples occurrence is higher in the emergency department.

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Low vacuum tube can reduce the hemolysis rate of blood sampling.

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Higher speed centrifugation could reduce centrifugation time and turnaround time.

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Low vacuum Barricor tube in emergency unit improve hemolysis rate and turnaround time.

The role of mineral metabolism and inflammation on dialysis vascular access failure

Thrombosis of arteriovenous fistula (AVF) is the leading cause of vascular access (VA) loss usually due to silent stenosis. Therefore, assessment of relevant risk factors of VA monitoring may provide insight into potential therapeutic targets for stenosis and thrombosis. The aim of this study was to evaluate the influence of cardiovascular risk factors (including inflammation and mineral metabolism dysfunctions) on the failure of internal AVF in HD patients.

128 HD patients with internal AVF were included in the study and followed up for two years. At baseline, VA morphology and function were followed by Doppler ultrasonography and serum albumin, prealbumine, C-reactive protein, orosomucoid, calcium, phosphorus, parathyroid hormone, bone-type alkaline phosphatase, osteoprotegerin and receptor activator of nuclear factor κB ligand were measured.

At baseline, 50 stenoses were detected but none of them required any intervention. Age and biological parameters did not significantly differ between patients with or without VA stenosis. Over the two year- follow up, VA thrombosis occurred in 19 patients. Preexisting stenosis of VA was present in 9/19 patients (47.3% of cases) (chi-square = 3.708, p = 0.0538). Despite the low rate of events, phosphorus [1.75 (0.95–2.77) vs 1.42 (0.47–3.22) mmol/L, p = 0.0416], Calcium x Phosphorus product [4.00 (2.00–5.90) vs 3.40 (1.10–6.80) mmol2/L2, p = 0.0676] and parathyroid hormone [165.00 (1.00–944.00) vs 79.50 (1.00–846.60) ng/L, p = 0.0814) levels were higher in the 19 thrombotic patients whereas all other biological parameters did not significantly differ.

These results, which confirm that VA thrombosis occurs more frequently upon preexisting stenosis, also demonstrate that mineral metabolism disorders, compared to inflammation, may contribute to VA dysfunction leading to thrombosis.

MACVIA-LR (Fighting Chronic Diseases for Active and Healthy Ageing in Languedoc-Roussillon): A Success Story of the European Innovation Partnership on Active and Healthy Ageing

The Région Languedoc Roussillon is the umbrella organisation for an interconnected and integrated project on active and healthy ageing (AHA). It covers the 3 pillars of the European Innovation Partnership on Active and Healthy Ageing (EIP on AHA): (A) Prevention and health promotion, (B) Care and cure, (C) and (D) Active and independent living of elderly people. All sub-activities (poly-pharmacy, falls prevention initiative, prevention of frailty, chronic respiratory diseases, chronic diseases with multimorbidities, chronic infectious diseases, active and independent living and disability) have been included in MACVIA-LR which has a strong political commitment and involves all stakeholders (public, private, patients, policy makers) including CARSAT-LR and the Eurobiomed cluster. It is a Reference Site of the EIP on AHA. The framework of MACVIA-LR has the vision that the prevention and management of chronic diseases is essential for the promotion of AHA and for the reduction of handicap. The main objectives of MACVIA-LR are: (i) to develop innovative solutions for a network of Living labs in order to reduce avoidable hospitalisations and loss of autonomy while improving quality of life, (ii) to disseminate the innovation. The three years of MACVIA-LR activities are reported in this paper.

Association between breast milk fatty acids and HIV-1 transmission through breastfeeding

A residual mother-to-child transmission of HIV through breastfeeding persists despite prophylaxis. We identified breast milk fatty acids (FA) associated with postnatal HIV transmission through breastfeeding in a case-control study. Cases (n=23) were HIV-infected women with an infant who acquired HIV after 6 weeks of age. Controls (n=23) were matched on infant׳s age at sample collection. Adjusting for maternal antenatal plasma CD4 T cell count, cis-vaccenic acid (18:1n-7) and eicosatrienoic acid (20:3n-3) were associated with HIV transmission in opposite dose-response manner: OR (tertile 3 versus tertile 1): 10.8 and 0.16, p for trend=0.02 and 0.03, respectively. These fatty acids correlated with HIV RNA load, T helper-1 related cytokines, IL15, IP10, and β2 microglobulin, positively for cis-vaccenic acid, negatively for eicosatrienoic acid. These results suggested a change in FA synthesis by mammary gland cells leading to increased cis-vaccenic acid in milk of mothers who transmitted HIV to their infant during breastfeeding.

Long term reference change value of creatinine in HIV-positive patients with anti-retroviral therapy: A new tool in clinical practice

BACKGROUND

The use of reference change value (RCV) instead of reference interval emerged as an alternative approach for longitudinal interpretation of biological marker. Follow-up of creatinine variation in HIV-positive adults remains a challenge in order to prevent renal complications.

OBJECTIVES

To determine the long term RCV of creatinine in HIV-positive adults receiving anti-retroviral therapy (ART) according to the use of tenofovir or ritonavir.

DESIGN AND METHODS

Longitudinal study of 24 months that include 124 HIV-positive patients followed in HIV outpatient unit. Plasma creatinine was measured at 0, 6, 12 and 24 months in order to calculate the RCV.

RESULTS

In the whole group, a 24-month RCV of creatinine was 22.5%. Whatever the ART, the index of individuality was <0.6. Significantly higher RCV of creatinine was observed in patients receiving the association tenofovir and ritonavir (28%) compared to the patients receiving i) tenofovir without ritonavir (21.9%), ii) no tenofovir but ritonavir (22.2%), and iii) no tenofovir and no ritonavir (19.7%).

CONCLUSIONS

The low value of index of individuality pinpointed that RCV should be used to identify critical change in serial creatinine results in HIV-positive adults. RCV of creatinine under ART was around 20% but reached 28% in case of association of tenofovir and ritonavir.

In vitro lipid peroxidation of intestinal bile salt-based nanoemulsions: potential role of antioxidants

Over the last decades, oxidative stress has been described as a deleterious phenomenon contributing to numerous noncommunicable diseases such as cardiovascular disease, diabetes, and cancers. As many authors ascribed the healthy effect of fruit and vegetable consumption mainly to their antioxidant contents, it has been hypothesized that their protection could occur from the gut. Therefore, the aim of this study was to develop an original and physiological model of nanoemulsions to study lipid peroxidation within the intestine and to assess the properties of potential antioxidants in this setting. Several nanoemulsions were compared in terms of physical characteristics and reactivity to 2,2'-azobis-(2-amidinopropane) hydrochloride (AAPH)-induced oxidation. Formulations included different types of lipids, a detergent (a conjugated bile salt or sodium dodecyl sulfate) and, finally, lipophilic antioxidants. Hemin and myoglobin were also tested as relevant potential oxidants. Fatty acid (FA) peroxidation was monitored by gas chromatography while malondialdehyde and antioxidant contents were measured by HPLC. Investigated nanoemulsions were composed of spherical or cylindrical mixed micelles, the latter being the least resistant to oxidation. In the experimental conditions, AAPH was the only efficient oxidant. Alpha-tocopherol and lutein significantly slowed FA degradation from 4 to 1 μM, respectively. On the contrary, beta-carotene did not show any protective capacity at 4 μM. In conclusion, the tested nanoemulsions were appropriate to assess antioxidant capacity during the intestinal phase of digestion.

Dietary exposure to silver nanoparticles in Sprague-Dawley rats: effects on oxidative stress and inflammation

Due to undesirable hazardous interactions with biological systems, we evaluated the effect of silver nanoparticles (AgNPs) intake on oxidative stress and inflammation. Rats received for 81 days a standard diet (Controls) or a standard diet plus 500 mg/d/kg BW AgNPs. We assayed plasma lipids, and oxidative stress was assessed by measuring liver and heart superoxide anion production (O₂°⁻) and liver malondialdehyde levels (MDA). Antioxidant status was appraised using plasma paraoxonase activity (PON), plasma antioxidant capacity (PAC) and liver superoxide dismutase activity (SOD). Liver inflammatory cytokines TNFα and IL-6 levels and plasma alanine aminotransferase (ALT) were assayed. Compared with Controls, AgNPs raised cholesterolemia (9.5%), LDL-cholesterol (30%), and lowered triglycerides (41%). They also increased liver (30%) and cardiac (41%) O₂°⁻ production, reduced PON activity (15%) and raised liver TNFα (9%) and IL-6 (∼12%). Plasma ALT activity rose (12%) after treatment with AgNPs. However, PAC and liver MDA and SOD activity were unchanged. These features indicate that exposure to 500 mg/d/kg BW of AgNPs results in liver damage by a dysregulation of lipid metabolism, highlighting liver and heart as the most sensitive organs to the deleterious effects. Our findings also demonstrate for the first time the oxidative and inflammatory effects of dietary AgNPs.

Metabolic intervention on lipid synthesis converging pathways abrogates prostate cancer growth

One of the most conserved features of all cancers is a profound reprogramming of cellular metabolism, favoring biosynthetic processes and limiting catalytic processes. With the acquired knowledge of some of these important changes, we have designed a combination therapy in order to force cancer cells to use a particular metabolic pathway that ultimately results in the accumulation of toxic products. This innovative approach consists of blocking lipid synthesis, at the same time that we force the cell, through the inhibition of AMP-activated kinase, to accumulate toxic intermediates, such as malonyl-coenzyme A (malonyl-CoA) or nicotinamide adenine dinucleotide phosphate. This results in excess of oxidative stress and cancer cell death. Our new therapeutic strategy, based on the manipulation of metabolic pathways, will certainly set up the basis for new upcoming studies defining a new paradigm of cancer treatment.

Effect of a high dose of simvastatin on muscle mitochondrial metabolism and calcium signaling in healthy volunteers

Statin use may be limited by muscle side effects. Although incompletely understood to date, their pathophysiology may involve oxidative stress and impairments of mitochondrial function and of muscle Ca(2+) homeostasis. In order to simultaneously assess these mechanisms, 24 male healthy volunteers were randomized to receive either simvastatin for 80 mg daily or placebo for 8 weeks. Blood and urine samples and a stress test were performed at baseline and at follow-up, and mitochondrial respiration and Ca(2+) spark properties were evaluated on a muscle biopsy 4 days before the second stress test. Simvastatin-treated subjects were separated according to their median creatine kinase (CK) increase. Simvastatin treatment induced a significant elevation of aspartate amino transferase (3.38±5.68 vs -1.15±4.32 UI/L, P<0.001) and CK (-24.3±99.1±189.3 vs 48.3 UI/L, P=0.01) and a trend to an elevation of isoprostanes (193±408 vs 12±53 pmol/mmol creatinine, P=0.09) with no global change in mitochondrial respiration, lactate/pyruvate ratio or Ca(2+) sparks. However, among statin-treated subjects, those with the highest CK increase displayed a significantly lower Vmax rotenone succinate and an increase in Ca(2+) spark amplitude vs both subjects with the lowest CK increase and placebo-treated subjects. Moreover, Ca(2+) spark amplitude was positively correlated with treatment-induced CK increase in the whole group (r=0.71, P=0.0045). In conclusion, this study further supports that statin induced muscular toxicity may be related to alterations in mitochondrial respiration and muscle calcium homeostasis independently of underlying disease or concomitant medication.

Accuracy of GFR predictive equations in renal transplantation: validation of a new turbidimetric cystatin C assay on Architect c8000

OBJECTIVES

To evaluate the Sentinel-PETIA cystatin C on Architect c8000 analyzer.

DESIGN AND METHODS

We assessed analytical performances and clinical relevance by comparison with a reference isotopic method in kidney transplant recipients.

RESULTS

This assay exhibited reliable precision and was close to the non standardized Siemens-PENIA method. All tested equations allowed reliable assessment of GFR.

CONCLUSIONS

Cystatin C improved GFR determination at the critical level of 60 mL/min/1.73 m². New formulas might be necessary after IFCC standardization.

An SOD rich melon extract Extramel prevents aortic lipids and liver steatosis in diet-induced model of atherosclerosis

BACKGROUND AND AIMS

Oxidative stress has been involved in the early steps of atherosclerosis and previous studies on hypercholesterolemic hamsters have shown that non-enzymatic antioxidant could prevent fatty streak formation. Therefore, we investigated whether a melon juice extract (Extramel((R))) rich in superoxide dismutase (SOD) would prevent the development of early atherosclerosis.

METHODS AND RESULTS

The effects of Extramel((R)) on plasma cholesterol, aortic fatty streak formation, hepatic steatosis, superoxide anion tissue production and NAD(P)H oxidase expression were studied in hamsters fed with an atherogenic diet (HF), receiving by gavage either water or Extramel((R)) at 0.7, 2.8 or 5.6mg/d. After 12 weeks of oral administration, Extramel((R)) lowered plasma cholesterol and non-HDL cholesterol and induced blood and liver SOD activities. It also strongly reduced the area of aortic fatty streak by 49-85%, cardiac (45%) and liver (67%) production of superoxide anion and liver p22(phox) subunit of NAD(P)H oxidase expression by 66%, and attenuated the development of hepatic steatosis.

CONCLUSION

These findings support the view that chronic consumption of melon juice extract rich in SOD has potential beneficial effects with respect to the development of atherosclerosis and liver steatosis, emphasizing its use as potential dietary therapy.

Regulation of oxidative stress by glycaemic control: evidence for an independent inhibitory effect of insulin therapy

AIMS/HYPOTHESIS

We examined whether type of diabetes and/or insulin treatment can modulate the impact of sustained hyperglycaemia and glycaemic variability as activators of oxidative stress.

METHODS

This was an observational study in 139 patients with diabetes, 48 with type 1, 60 with type 2 treated by oral hypoglycaemic agents (OHAs) alone and 31 with type 2 treated with insulin plus OHAs. In addition, two groups of ten patients with type 2 diabetes were investigated either before and after introducing insulin treatment (add-on insulin group) or before and after add-on OHA therapy to metformin (add-on OHA group). Oxidative stress was estimated from 24 h urinary excretion rates of 8-isoprostaglandin F2alpha (8-iso-PGF2alpha). HbA(1c) was assessed and mean amplitude of glycaemic excursions (MAGE) was estimated by continuous monitoring.

RESULTS

The 24 h excretion rate of 8-iso-PGF2alpha (median [range] picomoles per millimole of creatinine) was much higher (p < 0.0001) in type 2 diabetes patients treated with OHAs alone (112 [26-329]) than in the type 1 diabetes group (65 [29-193]) and the type 2 diabetes group treated with insulin (69 [30-198]). It was associated with HbA(1c) (F = 12.9, p = 0.0008) and MAGE (F = 7.7, p = 0.008) in non-insulin-treated, but not in insulin-treated patients. A significant reduction in 24 h excretion rate of 8-iso-PGF2alpha from 126 (47-248) to 62 (35-111] pmol/mmol of creatinine was observed in the add-on insulin group (p = 0.005) but not in the add-on OHA group.

CONCLUSIONS/INTERPRETATION

In type 1 and type 2 diabetes, insulin exerts an inhibitory effect on oxidative stress, a metabolic disorder that is significantly activated by sustained hyperglycaemia and glucose variability in non-insulin-treated type 2 diabetes.

Evolution of coronary artery calcifications following kidney transplantation: relationship with osteoprotegerin levels

We prospectively assessed the evolution of coronary artery calcification (CAC) and osteoprotegerin (OPG) levels after renal transplantation (RT). Eighty-three recipients were followed-up prospectively during 1 year. Blood was collected before (baseline) and after RT for determination of mineral metabolism parameters including OPG. CAC was measured by multidetector computed tomography at transplantation (baseline) and 1 year later. Progression of CAC was defined as a difference between the follow-up square-root transformed volume (SRV) and the baseline SRV >or= 2.5. By multivariate analysis, baseline OPG level, age and low LDL levels were significantly associated with baseline CAC. RT was accompanied by mineral metabolism improvement with a decrease of OPG from 955 [395-5652] to 527 [217-1818] pg/mL and parathyroid hormone from 94 [1-550] to 62 [16-410] pg/mL. Thirty-one percent of patients did not exhibit CAC at baseline. CAC diminished in 14.5%, stabilized in 59.2% and progressed in 26.3% of patients. Baseline CAC was associated with progression (OR 2.92 [1.02-8.36]). No significant association was found between OPG and CAC progression despite a higher baseline OPG level in progressors (1046 [456-3285]) vs. non-progressors (899 [396-5952] pg/mL). CAC at baseline, but not 1 year after RT, is independently associated with baseline OPG; posttransplant CAC progression is predicted by baseline CAC score.

Protein biochip array technology to monitor rituximab in rheumatoid arthritis

In rheumatoid arthritis (RA) there are currently no good indicators to predict a clinical response to rituximab. The purpose of this study was to monitor and determine the role of peripheral blood cytokine profiling in differentiating between a good versus poor response to rituximab in RA. Blood samples were collected at baseline and at 3 months from 46 RA patients who were treated with rituximab. Responders are defined by the presence of three of four American College of Rheumatology criteria: >or=20% decrease in C-reactive protein, visual analogical score of disease activity, erythrocyte sedimentation rate and improvement of the disease activity score (28) (four values) by >or=1.2 obtained at 3 months. Twelve cytokines were measured from serum collected on days 0 and 90 by proteomic array, including interleukin-6 (IL-6), tumour necrosis factor-alpha, IL-1a, IL-1b, IL-2, IL-8, interferon-gamma, IL-4, IL-10, monocyte chemoattractant protein-1, epidermal growth factor and vascular growth factor. We showed that C-reactive protein and IL-6 levels decrease significantly at 3 months in the responder group compared with baseline. At day 90 we identified a cytokine profile which differentiates responders and non-responders. High serum levels of two proinflammatory cytokines, monocyte chemoattractant protein-1 and epidermal growth factor, were significantly higher in the responder group at day 90 compared with non-responders. However, we were not able to identify a baseline cytokine profile predictive of a good response at 3 months. These findings suggest that cytokine profiling by proteomic analysis may be a promising tool for monitoring rituximab and may help in the future to identify responder RA patients.

Oxidative stress in rats fed a high-fat high-sucrose diet and preventive effect of polyphenols: Involvement of mitochondrial and NAD(P)H oxidase systems

Mitochondrial and NADPH oxidase systems and oxidative stress were investigated in 12 week high-fat high-sucrose (HFHS) diet-fed rats. A protective effect of wine polyphenol (PP) extract was also examined. In liver, maximal activities of CII and CII+III mitochondrial complexes were decreased but NADPH oxidase expression (p22(phox) and p47(phox)) and NADPH oxidase-dependent superoxide anion production were not modified, whereas oxidative stress (lipid and protein oxidation products and antioxidant systems) was increased with HFHS diet. In muscle, anion superoxide production was slightly increased while mitochondrial complex activities and lipid and protein oxidation products were not modified with HFHS diet. In heart, NADPH oxidase expression and superoxide anion production were increased, and maximal activity of mitochondrial respiratory chain complexes or oxidative stress parameters were not modified. Wine polyphenol extract had an inhibiting effect on liver oxidative stress and on heart NADPH oxidase expression and superoxide anion production, and on induction of hepatic steatosis with HFHS diet. Induction of mitochondrial dysfunction could be a primary event in the development of oxidative stress in liver, while in skeletal muscle and in heart the NADPH oxidase system seems to be mainly involved in oxidative stress. Wine polyphenol extract was shown to partially prevent oxidative stress in liver and heart tissues and to nearly completely prevent steatosis development in liver.

Multi-site, multi-country evaluation of analytical and operational performance of a low-mid volume chemiluminescent immunoassay analyzer

BACKGROUND

A new automated immunoassay low-mid volume (< or = 250 immunoassays/day) chemiluminescent analyzer, Abbott Architect i1000sR, was evaluated by seven laboratories around the world (4 in Europe, one each in Canada, Japan, and the U.S.A.) to demonstrate equivalent performance for key operating characteristics (e.g., precision, turn around time, limit of detection, functional sensitivity, and linearity).

METHODS

The laboratories followed standard protocols to assess precision, limit of detection (LoD), functional sensitivity, assay linearity, method comparison, and sample carryover. Turn around time for three stat assays (beta-hCG, BNP, and CK-MB) and the time required to complete workloads of 50 and 100 tests with a mixture of 75% routine tests and 25% stat tests was also evaluated.

RESULTS

Total precision was typically < 5% CV for nine immunoassays. Analytical performance met design goals and demonstrated equivalency to package insert data for assays on market and in use for an existing high volume immunoassay system. Stat turn around times were consistent with the fixed analytical time of 15.6 minutes and met the expectations of the laboratories. Measured test throughput ranged from 47 - 54 tests per hour and demonstrated that the analyzer was fit for the intended purpose of supporting a laboratory that performs < or = 250 immunoassays per day.

CONCLUSIONS

A multisite, international analyzer familiarization study is a practical means of confirming that a new instrument meets both a manufacturer's design specifications and users' real world expectations and provides a pragmatic test for the system. The experience of investigators at seven sites around the world indicates that a new fully automated chemiluminescent system is suitable for use.

Protein biochip array technology for cytokine profiling predicts etanercept responsiveness in rheumatoid arthritis

In rheumatoid arthritis (RA) there are currently no useful indicators to predict a clinical response to tumour necrosis factor-alpha (TNF-alpha) blockade. The purpose of this study was to determine the role of peripheral blood cytokine profiling in differentiating between a good versus poor response to etanercept in RA. Peripheral blood samples were collected at baseline and at 3 months from 33 patients with active disease who were treated twice weekly by etanercept therapy. Responders are defined by the presence of three of four American College of Rheumatology criteria: > or =20% decrease in C-reactive protein (CRP), visual analogue score of disease activity, erythrocyte sedimentation rate and improvement of the disease activity score (28; four values) by > or =1.2 obtained at 3 months. Twelve cytokines were measured from serum collected on days 0 and 90 by proteomic array (protein biochip array, Investigator Evidence, Randox France), including interleukin (IL)-6, TNF-alpha, IL-1a, IL-1b, IL-2, IL-8, interferon-gamma, IL-4, IL-10, monocyte chemoattractant protein (MCP)-1, epidermal growth factor (EGF) and vascular endothelium growth factor. Our results showed that high serum levels of MCP-1 and EGF were associated with a response to etanercept. In addition, the increase of two combined parameters CRP and EGF was predictive of a response to etanercept treatment at 3 months (sensitivity: 87.5% and specificity: 75%, accuracy: 84.4%). These findings suggest that cytokine profiling by proteomic analysis before treatment initiation may help to identify a responder patient to TNF-alpha blocking agents in RA.

Association of non-HDL cholesterol with subclinical atherosclerosis in HIV-positive patients

OBJECTIVES

To assess the relationship between non-classical cardiovascular (CV) risk factors including non-HDL cholesterol (non-HDL-C), apolipoprotein B, triglycerides to HDL ratio, LDL size, inflammation or oxidative stress parameters and carotid intima-media thickness (CIMT), in order to better identify prevention or therapeutic targets. In addition, we studied the relationship between metabolic syndrome (MS) and CIMT.

METHODS

Cross-sectional study including 232 HIV-positive (HIV+) adults (80% treated by combined antiretroviral therapy) extracted from the ANRS CO3 Aquitaine Cohort.

RESULTS

There was a significant association of higher non-HDL-C (p<0.01), apolipoprotein B (p<0.01) levels or TG/HDL ratio (p<0.05) with higher CIMT when compared the first vs fourth quartile, while there is no association between CIMT and LDL-C (p=0.09) or LDL size (p=0.55). In multivariate analysis, only the TG/HDL molar ratio > 1.5 tend toward significance (p=0.08). MS was observed in only 7.3% of patients with the NCEP-ATP III definition and 11.2% with the IDF criteria. Whatever the used definition, there was a significant association between MS presence and increased CIMT (p<0.05) in univariate and multivariate model.

CONCLUSIONS

Non-HDL-C, TG/HDL ratio and apolipoprotein B levels, which are closely linked to lipid disorders associated to the MS, appear as stronger predictive markers than LDL-C for screening subclinical atherosclerosis in HIV+ populations. Achieving non-HDL-C target defined by the NCEP-ATP III guidelines appears of great importance to reduce CV complications in HIV+ patients.

[Comparative study of six blood gas analysers]

An evaluation process directed by the biochemistry department of the UHC of Montpellier about acquisition of blood gas analysers for a point of care testing in 10 different medical care services. The values obtained by the different measurement machines have been compared taking into account the intra and inter measures variabilities. In this work, the results of 4 machines tested: Rapid-point 405, GEM Premier 3000, i-STAT 1 (série 300) and ABL 77 are compared with one i-STAT (série 200) and one OMNI S already available in the laboratory. The study lasted one month (november 2004). Each week, the two machines of the laboratory was compared with a new analyser randomly chosen between the four machines tested. In this study, including 21000 values, the statistical tests have been applied under the hypothesis that none of the measurement machine could be a "gold standard". Beside the classical research of correlation between the different values, we added the research of concordance between machines and the application of imperfect gold standard method. A high level of statistic concordance was observed between the different analysers. So the equipment has been selected using biological, analytic and computing criteria.

Effects of a Supplementation during Exercise and Recovery

The present study was designed to investigate whether a protein hydrolysate enriched in branched chain amino acids and antioxidants, trace and mineral elements, and vitamins would affect performance and fatigue. Eighteen sportsmen underwent testing before and after 28 days supplementation with either treatment in protein hydrolysate or placebo. Testing included exhaustive aerobic and anaerobic exercises with determination of blood lactate concentration through exercise and recovery and antioxidant status, but also measurements of maximal oxidative capacity (V. (max)) and citrate synthase activity (CS) from a resting muscle biopsy. Protein hydrolysate resulted in a significant decrease in fatigue indices, without affecting performances. A significant increase in enzymatic antioxidant and a decrease in oxidative damage were observed at rest after treatment but not with a placebo. Decrease in maximal blood lactate and improvement of blood lactate removal were only observed after protein hydrolysate treatment. Furthermore, CS increased significantly, whereas no change was observed in V. (max). In conclusion, this protein hydrolysate treatment induced adaptations that may promote a decrease in fatigue during exercises, potentially explained by changes in parameters used to represent oxidative damage and antioxidant status at rest and changes in lactate metabolism.

Waist Circumference Adds to the Variance in Plasma C-Reactive Protein Levels in Elderly Patients with Metabolic Syndrome

BACKGROUND

C-reactive protein (CRP), a nonspecific marker of the inflammatory status, is associated with cardiovascular disease risk factors and may be an important feature of the metabolic syndrome (MSX) in middle-aged subjects.

OBJECTIVES

We assessed the relationship of CRP levels to specific components of MSX and other potential determinants in apparently healthy elderly subjects living in the South of France.

METHODS

In the framework of the population-based POLA (Pathologies Oculaires Liées à l'Age) Study, performed in 2,404 subjects aged 60 years or more, we measured the plasma CRP levels. All subjects with known systemic inflammatory diseases, such as chronic bronchitis, cardiovascular disease, and diabetes, and those who were on systemic steroid therapy as well as subjects with CRP levels >10 mg/l were excluded from the study, leaving 1,709 subjects for the statistical analyses. MSX was defined according to NCEP (National Cholesterol Education Program) criteria. Other potential determinants were assessed through interviewer-based questionnaire.

RESULTS

We grouped the subjects into three categories based on the 75th and 25th percentiles, corresponding to 3.05 and 0.82, respectively. We compared subjects in the highest quartile, i.e., with CRP >/=3.05 mg/l, with those in the two intermediate quartiles, i.e., with 0.82 < CRP < 3.05, and those in the lowest quartile, i.e., with CRP <0.82 mg/l according to gender. MSX, which had a prevalence of 31%, was significantly associated with elevated CRP levels. Among MSX components, the strongest positive association with the highest quartile of CRP was with waist circumference in males as well as in females (age-adjusted odds ratio OR 3.06 and 95% confidence interval CI 1.82-5.14; OR 7.04 and 95% CI 4.79-10.34, respectively). Each component of the MSX, such as abnormal fasting plasma glucose (OR 2.90, 95% CI 1.69-4.99), triglycerides (OR 1.96, 95% CI 1.30-2.96), high-density lipoprotein cholesterol (OR 2.31, 95% CI 1.61-3.30), and blood pressure (OR 1.66, 95% CI 1.12-2.45), was significantly associated with high CRP values in elderly women only. In men, only current smoking was significantly associated with high CRP levels (OR 1.52, 95% CI 1.04-2.2). In multivariate analysis, the waist circumference remained significantly associated with high CRP levels, with a graded effect of CRP quartile whatever the gender. In men, current and former smoking remained significantly associated with the CRP levels. In women, the association observed in univariate analysis with fasting glucose or hypertension did not reach statistical significance in the multivariate analysis, while only a weak association could be observed with lipid parameters such as triglycerides and high-density lipoprotein cholesterol.

CONCLUSIONS

Abdominal adiposity adds to the variance in plasma CRP levels in elderly patients with MSX. This suggests that weight loss or other interventions targeted at adipocyte-related inflammation may represent an important means to prevent subclinical inflammation in the elderly, bearing a high risk of cardiovascular disease.

Dietary fat and the risk of age-related maculopathy: the POLANUT study

This study aimed at assessing the associations of dietary fat with the risk of age-related maculopathy (ARM), in the framework of a population-based study from southern France. Nutritional data were collected using a dietitian-administered food-frequency questionnaire. ARM was classified from retinal photographs using the international classification and included neovascular age-related macular degeneration, geographic atrophy, soft indistinct drusen, soft distinct drusen associated with pigmentary abnormalities. After multivariate adjustment, high total, saturated and monounsaturated fat intake were associated with increased risk for ARM (odds ratio (OR)=4.74, P=0.007; OR=2.70, P=0.04; and OR= 3.50, P=0.03, respectively). Total polyunsaturated fatty acid was not significantly associated with ARM. Total and white fish intake was not significantly associated with ARM, but fatty fish intake (more than once a month versus less than once a month) was associated with a 60% reduction in risk for ARM (OR=0.42, P=0.01).

Evaluation of an immunoassay (Abbott-IMX Analyzer) allowing routine determination of sirolimus: comparison with LC-MS method

BACKGROUND

The use of the immunosuppressive agent sirolimus is increasing in renal transplantation but its monitoring often requires high-performance liquid chromatography (HPLC) with ultra-violet (UV) or tandem mass spectrometric (MS-MS) detection. The aim of this study was to compare a new microparticle enzyme immunoassay (MEIA, Microparticle Enzyme Immunoassay) on IMx Abbott Analyser with a liquid chromatography-mass spectometry (LC-MS) method.

METHOD

The accuracy of immunoassay analytical performance including within run and between run imprecision and linearity was tested. For comparison studies, sirolimus level was then determined with the two methods on 98 samples from 52 transplant patients.

RESULTS

Total intra-assay and inter-assay variation coefficients were below 10% at the three levels tested, and the coefficient of linearity was r = 0.99. The values obtained were highly correlated with the LC-MS method (MEIA = 1.02LC-MS + 0.91; r(2) = 0.87). As a result, the immunoassay showed good performance, and clinical sample measurements were not affected by the method. The MEIA may be a useful alternative for routine monitoring of sirolimus.

New onset dyslipidemia after renal transplantation: is there a difference between tacrolimus and cyclosporine?

Lipid abnormalities including increased total cholesterol (TC), triglycerides (TG) and low density lipoprotein cholesterol (LDL-C) have been frequently reported in renal transplantation and could be involved in the high frequency of cardiovascular diseases in this population.

PATIENTS AND METHODS

Two hundred ninety-five patients were transplanted between January 1995 and October 2000 in our center. Two hundred two patients were included in this study. Seventy-six patients received tacrolimus (Tac), and 126 patients cyclosporine (CsA). Lipid parameters were assessed the day of transplantation and 1 year posttransplantation.

RESULTS

Serum lipids were similar between the two groups at D0. At M12, TC and LDL-C were significantly higher in the CsA group (6.14 +/- 1.37 vs 5.28 +/- 1.32 mmol/L; P < .05 and 3.98 +/- 1.05 vs 3.26 +/- 1.03 mmol/L; P < .05 CsA vs Tac, respectively). TG were comparable in both groups (1.86 +/- 1.07 vs 1.62 +/- 0.92 mmol/L; P = .55; CsA vs Tac). Incidence of de novo hypercholesterolemia was significantly higher in the CsA group (28 vs 8%) whereas incidence of hyperTG was similar in both groups. Prevalence of LDL-C was significantly higher in the CsA group (65% vs 31%; P < .001), whereas there was no difference in high density lipoprotein (HDL)-C levels.

DISCUSSION

Mean serum lipid levels and incidence and prevalence of hyperTC, especially LDL-C, was significantly higher in patients receiving CsA when compared with Tac. TG and HDL-C levels were similar. Although the study was retrospective, our results confirm that CsA increases lipid levels, whereas Tac does not.

CONCLUSION

Lipid disorders are frequently observed in renal transplant recipients. CsA, but not Tac, significantly increases incidence and prevalence of high TC and LDL-C.

Renal transplantation decreases osteoprotegerin levels

Vascular calcifications are an important risk factor for cardiovascular mortality and morbidity in patients with chronic renal failure. Osteoprotegerin, a soluble decoy receptor for receptor activator NFkB ligand, has emerged as an independent predictive factor of atherosclerosis and vascular calcification in hemodialysis patients. Sparse data are available on the evolution of osteoprotegerin after renal transplantation. The aim of this study was to follow the evolution of serum osteoprotegerin levels and biochemical risk factors after renal transplantation. Forty patients were included. Blood samples for analysis were collected before and 3 months after renal transplantation. Besides the expected diminution in calcium-phosphate product, we have shown an early normalization of osteoprotegerin (10.05 +/- 4.77 pmol/L to 4.59 +/- 2.26 pmol/L). This study demonstrates that kidney transplantation improves this risk factor for vascular calcifications. However, these preliminary results should be confirmed and extended by the follow-up of vascular calcifications in the long term.

Small dense low-density lipoprotein in renal transplant recipients: a potential target for prevention of cardiovascular complications?

BACKGROUND

Immunosuppressive therapy is frequently associated with dyslipidemia, which is involved in cardiovascular morbidity and mortality in transplant patients. Beyond classical factors, such as low-density lipoprotein (LDL) cholesterol (LDL-C), qualitative abnormalities of lipoproteins, such as presence of the atherogenic factor, small dense LDL, may be of interest for a cardiovascular risk assessment. This study was designed to explore LDL size in renal transplant recipients in relation to quantitative lipid parameters and apolipoprotein (apo) CIII polymorphism.

METHODS

Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), LDL-C, apoA1, apoB, apoCIII, and LDL size were measured in 62 patients of mean age 45 +/- 13 years including 71% men at 2 +/- 0.5 years after renal transplantation. Thirty-two patients received cyclosporine (CsA), while 30 received tacrolimus (FK). ApoCIII Sstl genotype was determined by restriction fragment length polymorphism.

RESULTS

The CsA group exhibited higher TC (P = .001), LDL-C (P = .004), non-HDL-C (P = .009), HDL-C (P = .03), apoB (P = .008), and apoCIII (P = .002) levels than the FK group. However, LDL-C (CsA: 3.7 +/- 1.2, FK: 3.0 +/- 0.6 mmol/L) and triglyceride levels (CsA: 1.55 mmol/L, FK: 1.37 mmol/L) were near the normal range in both groups. Allelic frequency of the sparse A2 allele associated with hypertriglyceridemia was 6%, similar to the general population. LDL size, which was comparable in the CsA and FK groups (25.87 +/- 0.89 vs 25.75 +/- 0.62 nm, respectively), inversely correlated with TG/HDL ratio (P = 10(-4)). Prevalence of small dense LDL (defined as <25.5 nm) was 26% in the CsA group and 33% in the FK group.

CONCLUSION

After LDL-C goal has been achieved, LDL size modulation may be taken into account in order to prevent cardiovascular complications.

Beta2-microglobulin, a uremic toxin with a double meaning

beta(2)M is a strong and independent indicator of hemodialysis patient outcomes and an excellent surrogate for middle molecules, and deserves to be routinely monitored and incorporated into dialysis adequacy targets. beta(2)M has a double meaning, reflecting both dialysis efficacy in terms of solute mass transfer and patient bioactivity. The work of Ward et al. in this issue warrants a study to test the hypothesis that long daily hemodiafiltration treatment would be the optimal renal replacement modality to improve dialysis patient outcomes.

Evaluation of a capillary zone electrophoresis system versus a conventional agarose gel system for routine serum protein separation and monoclonal component typing

Capillary zone electrophoresis of serum proteins is increasingly gaining impact in clinical laboratories. During 2003, we compared the fully automated capillary electrophoresis (CE) system from Beckman (Paragon CZE 2000) with the method agarose gel electrophoresis Sebia (Hydrasis-Hyris, AGE). This new study focused on the evaluation of analytical performance and a comparison including 115 fresh routine samples (group A) and a series of 97 frozen pathologic sera with suspicion of monoclonal protein (group B). Coefficients of variation (CVs %) for the five classical protein fractions have been reported to be consistenly < 9% in within-run and < 10% in between-run imprecision studies with the Paragon 2000 system. The results of the comparison study (group A) demonstrated a good correlation between the CE system and AGE, except for beta-globulin (r = 0.65). Among the 97 pathologic serum samples (group B), there were 90 in which we detected a monoclonal protein by immunofixation (IF) (immunosubtraction (IS) was not used). AGE and Paragon 2000 failed to detect 7 and 12 monoclonal proteins, respectively, leading to a concordance to 92% for AGE and 87% for Paragon 2000 for identifying electrophoretic abnormalities in this group. Beta-globulin abnormalities and M paraprotein were well detected with Paragon 2000. Only 81% (21 vs 26) of the gammopathies were immunotyped with IS by two readers blinded to the IF immunotype. The Paragon 2000 is a reliable alternative to conventional agarose gel electrophoresis combining the advantages of full automation (rapidity, ease of use and cost) with high analytical performance. Qualified interpretation of results requires an adaptation period which could further improve concordance between the methods. Recently, this CE system has been improved by the manufacturer (Beckman) concerning the migration buffer and detection of beta-globulin abnormalities.

High Prevalence of Small Dense LDL as an Underestimated Component of Heart Transplantation–Induced Dyslipidemia: Potential Role in Graft Coronary Vasculopathy?

Heart transplantation-induced dyslipidemia is a recognized risk factor for cardiac allograft vasculopathy that affects survival prognosis. Beyond increased lipids, low-density lipoprotein (LDL) size and systemic factors, including glucose intolerance, oxidative stress, and inflammation, must be taken into account as components of the atherosclerotic risk. The aim of this study was to explore the atherogenic profile of heart transplant recipients (HTR) by assessing lipid parameters, glycemia, oxidative stress status, and inflammation in 59 transplant patients (follow-up of 6 +/- 3 years) compared to 20 healthy volunteers. Classical hypercholesterolemia and hypertriglyceridemia were observed in HTR compared to controls, associated with increased apoCIII levels (0.13 +/- 0.6 vs 0.07 +/- 0.03 g/L, P < .01). Mean LDL size was reduced in HTR compared to controls (25.22 +/- 0.72 vs 26.06 +/- 0.54 nm, P < .001) with an abnormally high prevalence (69% vs 0%, P < .001) of small dense LDL (<25.5 nm). Hyperglycemia (7.3 +/- 3 vs 5.4 +/- 0.8 mmol/L, P < .05) and inflammation (high-sensitive CRP: 3.1 +/- 3 vs 1.6 +/- 0.9 mg/L, P < .001) were evidenced in HTR since no difference in oxidative stress parameters was observed. In conclusion, a high prevalence of small dense LDL is an important component of posttransplantation dyslipidemia.

[Study of lipoprotein (a) phenotypes in Ivorian subject]

The objective of this study was to identify the apo (a) phenotypes and to find a correlation between apo (a) isoform size and Lp (a) plasma level in Ivorian subjects. This study involved 30 healthy subjects (11 females and 19 males) aged of 35 +/- 2 years. Lp (a) plasma levels have been determined by technical ELISA, while phenotypes of apo (a) have been identified by agarose high resolution electrophoresis followed by Western blot. The Lp (a) plasma level in our population was 329 +/- 291 mg/l and 30% of our population's Lp (a) plasma levels were above 300 mg/l. 70% of our subjects have homozygous phenotype and 30% have heterozygous phenotype. Three apo (a) isoforms (S2, S3, S4) have been identified in homozygous subjects whereas four apo (a) isoforms (B, S2, S3, S4) have been detected in heterozygous subjects. Their sizes varied from 13 to 33 kringle 4.77% of our subjects had apo (a) isoforms whose sizes were above 22 kringle 4. No correlation has been observed between the size of apo (a) isoforms and the Lp (a) plasma level in homozygous subjects. Our results highlight apo (a) polymorphism in Ivorians. Homozygous phenotypes and large size apo (a) isoforms predominate in this population.

Changes in osteoprotegerin/RANKL system, bone mineral density, and bone biochemicals markers in patients with recent spinal cord injury

This study analyzed the temporal and regional variations in bone loss and explored bone cell activities via biochemical markers during an extended follow-up in patients with spinal cord injury (SCI). In parallel, the possible role of the osteoprotegerin (OPG)/RANKL system in disuse osteoporosis was investigated. Seven male patients with acute and complete SCI (31.3 +/- 9.5 years) and 12 able-bodied (AB) men (26.9 +/- 4.2 years) participated in the study. Measurements were performed 16, 24, 36, 48, and 71 weeks after injury. At week 16, marked calcium homeostasis disturbance and a concomitant increase in bone resorption markers were observed, reflecting an intense bone degradation process. Resorption activity decreased continuously with time. Contrasting with the great rise in the resorption markers, the bone formation markers showed little variation. During the period of investigation, a loss in bone mineral density (BMD) was demonstrated for the total body (-4.3%), pelvis (-15.7%) and lower limbs (-15.2%), whereas BMD did not change at the lumbar spine, upper limbs, or skull. At all stages, SCI patients had lower serum RANKL levels and higher serum OPG levels than did AB controls, but no significant variation with time was observed for either cytokine. These findings suggest that bone resorption persisted long after SCI and specifically affected BMD at sublesional sites. The marked modification of serum OPG/RANKL levels in SCI patients suggests that this system is affected, in disuse osteoporosis. However, the precise biologic role of the OPG/RANKL system in the bone tissue of SCI patients has yet to be determined.

Dichotomous responses of inter and postprandial hyperglycaemia to short-term calorie restriction in patients with type 2 diabetes

BACKGROUND

In type 2 diabetes the effects of short-term calorie restrictions on glycaemia are usually judged on fasting plasma glucose. As fasting duration rarely exceeds 2-3 h, we determined the effects of calorie restriction over different daytime periods using a continuous glucose monitoring system (CGMS) in noninsulin-using patients with type 2 diabetes.

DESIGN

Fourteen poorly controlled (mean HbA1c = 9.3%) overweight or obese patients (mean body mass index = 30.1 +/- 0.7 kg m(-2)) with type 2 diabetes were investigated twice with a CGMS, at baseline and at the end of a 18-day calorie-restricted diet (1490 kcal day(-1)). Areas under curves (AUCs) of 24-h glucose monitoring were measured and divided into postprandial and interprandial AUCs according to meal times.

RESULTS

Areas under curves of 24-h glucose monitoring were significantly decreased after dieting: -37%, P = 0.0047. Both post and interprandial AUCs were significantly diminished (-26%, P = 0.0186 and -48%, P = 0.0037, respectively), but changes in interprandial AUCs were more marked than changes in postprandial AUCs (P = 0.0060). Nycthemeral peaks of glucose were observed at mid-morning times and were not significantly different before (242 +/- 15 mg dL(-1)) and after dieting (227 +/- 16 mg dL(-1)).

CONCLUSIONS

Short-term calorie restriction in overweight or obese patients with type 2 diabetes resulted in dichotomous responses between interprandial and postprandial glycaemic excursions. The resistance of mid-morning glucose peaking to calorie restriction should result in additional dietary or pharmacological measures at breakfast.

A thromboxane effect of a hydroxytyrosol-rich olive oil wastewater extract in patients with uncomplicated type I diabetes

OBJECTIVE

To assess the antioxidant/non-antioxidant effects of a hydroxytyrosol (HT)-rich phenolic extract from olive mill wastewaters administered with a breakfast.

DESIGN, SETTING AND SUBJECTS

Five type I diabetic patients received 25 mg of HT the first day and 12.5 mg/day the following 3 days. Blood sampling was carried out at T(0) (baseline) and T(4d) just before the breakfast + HT administration and at time points 1, 2, 3 and 4 h after T(0). Urines (24-h) were collected from T(0) to T(4d). Baseline HbA1c was generally inferior to 10%, glycemia was within the range 6-24 mmol/l, whereas total cholesterol, HDL-chol and triglycerides were normal.

RESULTS

The major finding was the 46% decrease in the serum TXB(2) production after blood clotting at T(4d). Plasma vitamin A, E, beta-carotene were not changed. Vitamin C tended to increase (P = 0.075). Plasma antioxidant capacity was enhanced at T(0)+1 h only, whereas its main determinants (albumin, bilirubin, uric acid) were not modified. Urinary 8-isoPGF(2alpha) levels were highly variable and were not affected significantly by HT administration.

CONCLUSION

The major effect of HT accounts for an antiaggregating platelet action, leading to a possible prevention of thrombotic and microthrombotic processes.

The V-Twin system (Dade Behring Laboratories): A useful tool for immunosuppressive drug monitoring

The predose trough cyclosporine (CsA) level (C0) was widely used to assess the possibility of drug nephrotoxicity. Owing to its potential limitation as an indicator of total drug exposure, 2-hour postdose (C2) monitoring has been considered to be a more accurate marker. The V-Twin analyzer (Vital SC, Netherlands) conceived for EMIT technologies (Dade Behring Laboratories) is proposed herein to determine CsA levels using a specific calibrator without any dilution, as well as tacrolimus (FK) and mycophenolate mofetil (MMF) levels. Both CsA (C0: n = 133 and C2: n = 55) and FK (n = 121) EMIT assays were compared to the RIA CsA assay (DiaSorin Laboratory) and to the MEIA tacrolimus assay (Abbott Laboratory), respectively. In addition, the feasibility of MMF EMIT assay was evaluated. Overall, 309 transplant patients were included in this study. For all parameters tested, total imprecision studies were lower than 10%, and the coefficient of linearity was r(2) > .99. For the CsA kit, the range of linearity was between 25 and 500 ng/mL for the C0 and 400 and 2000 ng/mL for the C2 assay. The values obtained were highly correlated with the RIA for the C0 levels (EMIT = 0.9 RIA+3.66; r = .97) and for the C2 levels (EMIT = 0.89 RIA-14.2; r = .956). Similar results were obtained with the EK EMIT kit, with a linearity range between 3 and 30 ng/mL, and a high concordance with the MEIA test (EMIT = 0.98 RIA+1.09; r = .96). Preliminary MMF results in 59 sera, containing from 0.1 to 30 microg/mL, showed that this examination could be included as a routine. The V-twin system is a useful tool for routine monitoring with a single method for C0 and C2 cyclosporine, tacrolimus, and mycophenolate levels.

Preliminary evaluation of a new chemiluminescence assay (liaison cyclosporine; diasorin laboratories) allowing both C0 and C2 cyclosporine levels determination: Comparison with RIA method

Cyclosporine (CsA) monitoring is generally assessed by trough concentration determinations (C0). Recently, the 2-hour postdose CsA level (C2) has been proposed to be a better measurement to predict graft outcome and prevent toxicity. However, using the available methods, C2 determinations require external dilution, which impairs the precision and practicability of the assay. This study assessed the performance characteristics of a new competitive chemiluminescence immunoassay (CLIA, DiaSorin Laboratories, Anthony, France) for the determination of both C0 and C2 CsA concentrations in whole blood on a Liaison analyzer. The results were compared with the RIA method (DiaSorin) used in our laboratory as a reference technique. Analytical performances showed that the total intra-assay variation coefficients (CVs) on the CLIA Liaison ranged from 7.6% to 11.3%, while the between-day imprecision was 11% (15.2%, 11.5%, and 6.5%). The linearity of the method was estimated over the range of 30 to 2400 ng/mL as a correlation coefficient of r = .997. Recoveries, which were checked by adding pure CsA to CsA-free blood, showed a mean value of 86%. A total of 236 whole-blood samples (31% women, 69% men of mean age 45 +/- 17 years) were subjected to a comparative study of CLIA-CsA versus RIA (radioimmunoassay) values, yielding a correlation coefficient >0.90 (CLIA = 0.825RIA+21.611; r(2) > .90). In conclusion, the CLIA Liaison CsA kit represents an alternative to the radioisotopic method, which allows both C0 and C2 determinations without any preanalytical step. The chemiluminescence method demonstrated good analytical performance and practicability in routine use.

Immunonephelometric determination of fibrinogen on citrated or heparinized plasma: comparison with functional Clauss method

BACKGROUND

Fibrinogen is routinely determined by functional assay on citrated plasma in the hematology department. However, immunoassay can be performed easily with nephelometric analyzer in the clinical chemistry laboratory allowing automatization. The aim of this study was first to compare the clotting von Clauss method (activity assay) with an immunonephelometric method (antigen assay) on the BN ProSpec (Dade Behring). Moreover, we evaluated the possibility of collecting blood samples on heparin to facilitate blood collection for clinicians and reduce required blood collection volumes for dosages.

METHODS

In a first step of experiment, the accuracy of immunonephelometric analytical performance was tested on heparinized and citrated tubes. For comparison studies, fibrinogen activity was then determined on citrated tubes in the hematology department and antigen measurement was performed on both citrated and heparinized plasma from 130 consecutive patients.

RESULTS

As a result, the immunonephelometric method shows reliable performance and clinical sample measurements are not affected by the method used, validating the use of heparinized plasma samples for fibrinogen antigen determination with Dade Behring reagents.

Lack of oxidative stress in a selenium deficient area in Ivory Coast--potential nutritional antioxidant role of crude palm oil

BACKGROUND

Previous studies have described an important selenium deficiency in a mountain region (Glanle) in the west of Ivory Coast.

AIM OF THE STUDY

To assess the antioxidant capacity of subjects from a selenium deficient area in Ivory Coast (Glanle region).

METHODS

This study involved 57 subjects, 18 to 69 years old, living in the Glanle region and 56 healthy controls living in the southern coastal region (Bodou). In the Glanle region families consume basically a vegetarian and crude palm oil diet, whereas in the Bodou region, families eat a fish-based diet with principally refined palm oil. Fasting blood samples were collected to assess the following parameters: lipid status (plasma total lipids; total-, HDL and LDL-cholesterol; triglycerides; phospholipids; fatty acid composition), plasma protein status (total protein, albumin, transthyretin, orosomucoid, CRP, transferrin), antioxidant capacity (plasma selenium, uric acid, retinol, alpha-tocopherol and tocotrienols levels, plasma seleno-glutathione peroxidase (GSHPx) activity) and oxidative stress markers (malondialdehyde (MDA) and advanced oxidation protein products (AOPP)).

RESULTS

The mountain region samples (Glanle) were characterized by significantly lower plasma albumin, total-, HDL- and LDL-cholesterol, retinol and selenium levels, plasma PUFA content and GSHPx activity, but significantly higher alpha-tocopherol index and total tocotrienol level, than controls from the coastal area (Bodou). These results suggest a higher exposure risk to oxidative stress for the mountain region subjects. However, the absence of oxidative damage in this group provides evidence of a selenium independent protection mechanism against oxidative stress. This protection is related to lower plasma LDL cholesterol and PUFA content, and to higher alpha-tocopherol index, delta and total tocotrienols.

CONCLUSION

The long-term consumption of crude palm oil could be considered as an effective protective factor against oxidative stress.

Mechanism of in vitro heme-induced LDL oxidation: effects of antioxidants

BACKGROUND

Heme protein toxicity, owing to generation of reactive oxygen species most likely by direct interaction between heme iron and hydrogen peroxide (H2O2), may be involved in various pathologies, including atherogenesis and pigmentary acute renal failure. The aim of this study was to investigate the mechanism of heme cytotoxicity and the effects of antioxidant therapies in an in vitro model of heme-induced low-density lipoprotein (LDL) oxidation.

MATERIALS AND METHODS

Human LDLs were exposed to heme, iron (Fe), protoporphyrin (PPIX) and PPIX-Zinc (Zn) with or without H2O2. Lipid peroxidation was monitored by measurement of conjugated diene formation (at the 234-nm absorbance). The effect of various antioxidants, such as vitamin E and vitamin C, reduced glutathione (GSH), and oxidized glutathione (GSSG), mannitol and desferoxamine (DFO) was further investigated in the established in vitro model of LDL oxidation.

RESULTS

Incubation of LDLs in the presence of heme/H2O2 induced lipid peroxidation with the optimal oxidation rate being at 5 microm heme/100 microm H2O2 doses. By contrast, incubation of LDL with H2O2, Fe, Fe/H2O2, PPIX, PPIX/H2O2, heme or PPIX-Zn did not initiate any LDL oxidation. In vitro, the vitamin E load protected native LDLs against heme/H2O2 oxidative modifications. Incubation of LDLs with increasing doses of vitamin C, GSH and DFO conferred a dose-dependent protection, while mannitol and GSSG had no effect.

CONCLUSIONS

Initiation and propagation of heme-induced lipid peroxidation is not mediated by a Fenton reaction but depends on specific interactions between heme and H2O2. It may result from the generation of ferryl and perferryl radicals derived from hemic Fe and H2O2 interactions. A protective effect of vitamins E, C, GSH and DFO was demonstrated in this model.

Does systemic inflammation trigger local exercise-induced oxidative stress in COPD?

Inflammatory abnormalities may be involved in the inadequate basal oxidant/antioxidant balance and local exercise-induced oxidative stress in chronic obstructive pulmonary disease (COPD) patients. The time course of oxidative stress and inflammation was investigated in 10 COPD patients and seven healthy subjects before and after local dynamic quadriceps endurance exercise at 40% of maximal strength. Venous samples were collected before, immediately after and up to 48 h after exercise. At rest, levels of an oxidant released by stimulated phagocytes, the superoxide anion, were significantly higher in patients, as were plasma levels of C-reactive protein, tumour necrosis factor-alpha and interleukin-6, inflammatory markers. An inverse relationship was found between baseline C-reactive protein levels and endurance time in patients. Six hours after exercise, superoxide anion release and levels of protein oxidation products, an index of oxidative stress, increased similarly in both groups, whereas thiobarbituric acid reactive substance levels, another index of oxidative stress, increased significantly only in patients. Plasma nonenzymatic antioxidant and inflammatory cytokine levels were unchanged by the exercise protocol. The increased baseline systemic inflammation in chronic obstructive pulmonary disease patients could be related to disturbed oxidant/antioxidant balance, and, together, these may have triggered the exercise-induced oxidative stress. The absence, however, of local exercise-induced systemic inflammation suggests that additional mechanisms explain local exercise-induced oxidative stress.

Determination of beta2-microglobulin in biological samples using an immunoenzymometric assay (chemiluminescence detection) or an immunoturbidimetric assay: comparison with a radioimmunoassay

Monitoring beta2-microglobulin (beta2M) in biological fluids has gained considerable interest in pathologies such as haematologic malignancies, renal diseases, and chronic inflammatory diseases. Due to limitations of the RIA in the routine laboratory, we measure beta2M with non-isotopic methods. 189 patients suffering from myeloma (n=66), end stage renal failure (n=54) or inflammation (n=69) were included in this study. beta2M was determined in serum, urine and dialysate using an immunoenzymometric assay with chemiluminescence detection [Immulite Diagnostic Products Corporation (DPC), La Garenne Colombes, France] and an immunoturbidimetric assay (Olympus, Rungis, France). The data were compared with a radioimmunoassay (Immunotech, Marseille, France) taken as a reference. Using serum samples, the immunoenzymometric assay with chemiluminescence detection and the immunoturbidimetric assay have reliable analytical performances. Values obtained with serum samples are highly correlated with the radioimmunoassay (DPC/RIA r2=0.84; Olympus/RIA r2=0.94) whatever the type of pathology; however an over-estimation which could be related to cross reactivity with beta2M fragments was observed with the RIA method as suggested by crossover calibration and recovery studies. Values obtained with urinary samples (n=96) are closely related to those obtained with the RIA (DPC/RIA r2 = 0.98; Olympus/RIA: r2=0.99). Despite the low levels observed in dialysate (n=57) good correlations were observed between Olympus vs DPC (r2=0.85). By contrast, the two non-isotope methods are poorly related with the RIA method (DPC vs RIA r2=0.47 and Olympus vs RIA r2=0.54). In conclusion, the immunoenzymometric assay with chemiluminescence detection or the immunoturbidimetric assay could be used in the routine laboratory in order to determine beta2M in plasma, urine and dialysate.

Decrease in LDL size in HIV-positive adults before and after lopinavir/ritonavir-containing regimen: an index of atherogenicity?

BACKGROUND

Hypertriglyceridemia (HTG) is frequently observed during highly active antiretroviral therapy (HAART) including protease inhibitor. Apolipoprotein (apo) CIII could be involved in this HTG by inhibition of triglyceride (TG) hydrolysis, which leads to the occurrence of small dense low density lipoprotein (sdLDL), a recognized cardiovascular risk factor.

OBJECTIVE

To characterize the influence of lopinavir/ritonavir-containing regimen on lipoprotein profile.

DESIGN AND METHODS

24 antiretroviral-experienced HIV infected adults (including 14 patients in therapeutic interruption of at least 2 months) and 14 HIV uninfected healthy controls were enrolled. Serum lipid parameters (total cholesterol (TC), HDL-C, LDL-C, TG, apoA1, apoB, apoCIII), lipoprotein composition and LDL size were determined before initiation of lopinavir/ritonavir-containing regimen, and at 1 and 3 months thereafter.

RESULTS

At baseline an atherogenic lipid profile was evidenced, characterized by a moderate HTG associated to a smaller mean LDL size (25.16 vs 25.93 nm, P<0.001), an enrichment in TG of LDL (11.4 vs 6.0%, P<0.01) and a high prevalence of sdLDL (75 vs 7%, P<0.01) when compared to controls. After 1 month of lopinavir/ritonavir-containing regimen, a significant reduction of LDL size (24.81 vs 25.16 nm, P<0.05) and a significant increase in cholesterol total (5.53 vs 4.49 mmol/l, P<0.001), in TG (4.20 vs 2.01 mmol/l, P<0.001), in apoA1 (1.28 vs 1.11 g/l, P<0.001), in apoB (1.08 vs 0.94 g/l, P<0.01), in apoCIII (0.16 vs 0.10 g/l, P<0.001), in TG percentage in LDL (14.4 vs 11.4, P<0.05) and in TG percentage in HDL (10.2 vs 8.3, P<0.05) were observed.

CONCLUSIONS

Advanced stage of HIV infection is associated with an atherogenic lipid profile including a high prevalence of sdLDL. Lopinavir/ritonavir-containing regimen accentuates the reduction of LDL size. Since fibrates decrease TG and increase LDL size, they appear as a logical option to manage HAART-induced HTG.

[Vascular access, an underestimated source of inflammation in dialysis patients]

The surveillance of inflammation in dialysis patient, by means of sensitive markers such as CRP, is strongly recommended in a continuous quality improvement treatment approach. Chronic inflammation being deleterious via several pathways including malnutrition, accelerated arteriosclerosis and beta 2M-amyloidosis, microinflammation must diagnosed and corrected as soon as possible in dialysis patients. Vascular access represents an underestimated source of inflammation in hemodialysis patients. In the absence of organic cause of inflammation, the vascular access should be always incriminated and meticulously investigated. Withdrawing the suspected prosthetic or unused material (PTFE or catheter) should be considered as the best way of correcting the inflammation and restoring the recombinant erythropoietin (EPO) activity in the dialysis patient.

[Is C-reactive protein a marker of inflammation?]

C-reactive protein (CRP) is the prototype of acute-phase protein which is secreted by the liver in response to a variety of inflammatory cytokines. Levels of CRP can increase up to 1000-fold very rapidly after the onset of inflammation and decrease just as rapidly with the resolution of aggression. CRP is a member of the ancient highly conserved pentraxin family of proteins and it is arranged in a cyclic homopentameric structure. The important role of CRP in innate immunity is largely due to its opsonizing abilities, its capability to activate human complement and to bind to immunoglobulin G receptors. CRP can bind phosphocholine largely present in bacterial membranes, cell membrane and lipoproteins, in addition CRP can recognize nuclear constituent in damaged cells. CRP can activate C3 convertase through the classical pathway but not C5 convertase resulting in generation of opsonic complement fragments. Interactions of CRP with Fc receptors lead to the generation of proinflammatory cytokines and reactive oxygen species by monocyte/macrophage while inhibit neutrophiles functions. Recently, CRP was demonstrated to play an active role in atherogenesis and it has been largely proven that a microinflammatory state as defined by a moderate increase in CRP (up to 3 mg/l), is associated with an increased risk for arterial disease. Moreover it has been postulated that CRP may be a useful tool for monitoring drug therapy.

Evidence of local exercise-induced systemic oxidative stress in chronic obstructive pulmonary disease patients

Chronic inactivity may not be the sole factor involved in the myopathy of chronic obstructive pulmonary disease (COPD) patients. One hypothesis is that exercise-induced oxidative stress that leads to muscle alterations may also be involved. This study investigated whether exercise localised to a peripheral muscle group would induce oxidative stress in COPD patients. Eleven COPD patients (FEV1 1.15+/-0.4 L (mean+/-SD)) and 12 healthy age-matched subjects with a similar low quantity of physical activity performed endurance exercise localised to a peripheral muscle group, the quadriceps of the dominant leg. The authors measured plasma levels of thiobarbituric reactive substances (TBARs) as an index of oxidative stress, the release in superoxide anion (O2*-) by stimulated phagocytes as an oxidant, and blood vitamin E as one antioxidant. Quadriceps endurance was significantly lower in the COPD patients compared with healthy subjects (136+/-16 s versus 385+/-69 s (mean+/-SEM), respectively). A significant increase in TBARs 6 h after quadriceps exercise was only found in the COPD patients. In addition, significantly higher O2*- release and lower blood vitamin E levels were found in COPD patients than in controls at rest. This blood vitamin E level was significantly correlated with the resting level of plasma TBARs in the COPD patients. This study mainly showed that quadriceps exercise induced systemic oxidative stress in chronic obstructive pulmonary disease patients and that vitamin E levels were decreased in these patients at rest. The exact relevance of these findings to chronic obstructive pulmonary disease myopathy needs to be elucidated.