Contribution de l'étude CoLaus à l'élucidation des déterminants de l'acide urique sérique. [Contribution of the CoLaus study to decipher the determinants of serum uric acid].

Asymptomatic hyperuricemia affects one in five adults in the general population and is associated with elevated cardiovascular risk. It is however not clear whether asymptomatic hyperuricemia is a cause or simply a marker of conditions associated with high cardiovascular risk. Sex, age, obesity, renal function and selected drugs are major determinants of serum uric acid. Moreover, recent genome-wide association studies have identified new genes involved in the control of serum uric acid levels, in particular SLC2A9, which encodes a urate transporter located in the kidney. A genetic score based on several genetic variants associated with serum uric acid is strongly associated with the risk of gout, but not with cardiovascular events so far.

Expression of interleukin-3 and tumor necrosis factor-beta mRNAs in cultured microglia.

The function of interleukin-3 (or multi-CSF) in the hemopoietic system has been studied in great detail. Although its growth promoting activity on brain microglial cells has been confirmed both in vitro and in vivo, its presence in the brain and even in cultured brain cells has repeatedly been questioned. We have shown recently that isolated rat microglia express mRNA(IL-3) and synthesize IL-3 polypeptide. It is shown here by use of the PCR method, that mRNA(IL-3) is found also in C6 glioblastoma, in rat aggregate cultures, and in newborn and adult rat brain. Quantitation of amplified cDNA(IL-3) was achieved by non-competitive RT-PCR using an elongated internal standard. IL-3 messenger RNA was almost undetectable in vivo and low in (serum-free) aggregate cultures. In isolated microglia, mRNA(IL-3) was increased upon treatment with LPS, PHA, with the cytokines IL-1 or TNF-alpha, with retinoic acid, dbcAMP or the phorbol ester TPA. Effects of LPS were inhibited by dexamethasone, while the glucocorticoid by itself had no effect on basal IL-3 expression. LPS increased mRNA(IL-3) in a concentration-dependent manner beginning with 10 pg/ml and reaching plateau levels at 10 ng/ml. LPS also increased mRNAs of TNF-alpha and TNF-beta. TNF-alpha mRNA was already detectable in untreated microglia and LPS-increased levels were sustained for a few days. In contrast, TNF-beta mRNA was observed only between 4 and 16 h of LPS incubation. It was absent in LPS-free microglia, and after 24 h of LPS-treatment or later.(ABSTRACT TRUNCATED AT 250 WORDS)

Large-scale analysis of orthologs and paralogs under covarion-like and constant-but-different models of amino acid evolution.

Functional divergence between homologous proteins is expected to affect amino acid sequences in two main ways, which can be considered as proxies of biochemical divergence: a "covarion-like" pattern of correlated changes in evolutionary rates, and switches in conserved residues ("conserved but different"). Although these patterns have been used in case studies, a large-scale analysis is needed to estimate their frequency and distribution. We use a phylogenomic framework of animal genes to answer three questions: 1) What is the prevalence of such patterns? 2) Can we link such patterns at the amino acid level with selection inferred at the codon level? 3) Are patterns different between paralogs and orthologs? We find that covarion-like patterns are more frequently detected than "constant but different," but that only the latter are correlated with signal for positive selection. Finally, there is no obvious difference in patterns between orthologs and paralogs.

Photodynamic Diagnosis in Non-Muscle-Invasive Bladder Cancer

Objective This paper reviews the development and clinical validation of photodynamic diagnosis (PDD) of bladder cancer. Methods The authors reviewed the literature on the development of PDD, in particular the evidence for the clinical efficacy of hexaminolevulinate PDD in the diagnosis of bladder cancer. Results After initial work on ultraviolet cystoscopy following oral tetracycline, the focus of PDD research shifted to the use of synthetic porphyrins. First, the prodrug delta-aminolevulinic acid (ALA) was shown to cause a transient but significant accumulation of protoporphyrin IX (PpIX) in malignant or premalignant bladder tissue. Excitation by blue light leads to PpIX fluorescence (red), which distinguishes tumour from normal tissue (blue). Hexaminolevulinate (HAL, Hexvix), an ester of ALA, was then developed and has greater bioavailability and stability than the parent compound. It has been approved for clinical use in the diagnosis of bladder cancer. Clinical studies have shown that HAL PDD detects tumours, including carcinoma in situ (CIS), that are missed by conventional white-light cystoscopy. Conclusions HAL PDD is a valuable aid to the detection of bladder tumours, including CIS.

Is amoxicillin/clavulanic acid sufficient for preemptive antibiotic therapy in type III grade open fractures ?

The risk of infection after type III° open fractures is high (10-50%).Preemptive antibiotic therapy may prevent posttraumatic infection andimprove the outcome. Recommendations about the type and durationof antibiotic vary among the institutions and it remains unclear whethergram-negative bacilli or anaerobs need to be covered. In Europe, themost commonly recommended antibiotic is amoxicillin/clavulanic acid.We retrospectively analyzed microbiology, characteristics and outcomeof patients with open type III° fractures treated at our institution.Methods: Between 01/2005 and 12/2009 we retrospectively includedall type III grade open fractures of the leg at our institution classifiedafter Gustilo into type IIIA, IIIB and IIIC. Demographic characteristics,clinical presentation, microbiology, surgical and antibiotic treatmentand patient outcome were recorded using a standardized case-reportform.Results: 30 cases of patients with type III° open fractures wereincluded (25 males, mean age was 40.5 years, range 17-67 years).27 fractures (90%) were located on the lower leg and 3 (10%) on theupper leg. Microbiology at initial surgery was available for 19 cases(63%), of which 10 grew at least one organism (including 8 amoxicillin/clavulanic acid-resistant gram-negative bacilli [GNB], 7 amoxicillin/clavulanic acid-resistant Bacillus cereus), 11 were culture-negative.Preemptive antibiotics were given in all cases (100%) for an averageduration of 8.5 days (range 1-53 days), the most common antibioticwas amoxicillin/clavulanic acid in 60% (n = 18). 11 cases just receivedpreemptive antibiotic treatment, in 19 of 30 cases the antibiotic therapywas changed and prolonged. Microbiology at revision surgery wasavailable for 25 cases and 22 grew at least one pathogen (including32 amoxicillin/clavulanic acid-resistant gram-negative bacilli and 10amoxicillin/clavulanic acid-resistant Bacillus cereus), 3 were culturenegative.Conclusions: At initial surgery, most common isolated organismswere coagulase-negative staphylococci (43%), Bacillus cereus (23%),and gram-negative bacilli (27%), and others (7%) of which 48% wereresistant to amoxicillin/clavulanic acid. At revision surgery, isolatedorganisms were gram-negative bacilli (64%), Bacillus cereus (20%),and others (16%) of which 88% were resistant to amoxicillin/clavulanicacid. The spectrum of amoxicillin/clavulanic does not cover the mostcommon isolated organisms.FM32

Fracture risk and zoledronic acid therapy in men with osteoporosis.

BACKGROUND: Fractures in men are a major health issue, and data on the antifracture efficacy of therapies for osteoporosis in men are limited. We studied the effect of zoledronic acid on fracture risk among men with osteoporosis. METHODS: In this multicenter, double-blind, placebo-controlled trial, we randomly assigned 1199 men with primary or hypogonadism-associated osteoporosis who were 50 to 85 years of age to receive an intravenous infusion of zoledronic acid (5 mg) or placebo at baseline and at 12 months. Participants received daily calcium and vitamin D supplementation. The primary end point was the proportion of participants with one or more new morphometric vertebral fractures over a period of 24 months. RESULTS: The rate of any new morphometric vertebral fracture was 1.6% in the zoledronic acid group and 4.9% in the placebo group over the 24-month period, representing a 67% risk reduction with zoledronic acid (relative risk, 0.33; 95% confidence interval, 0.16 to 0.70; P=0.002). As compared with men who received placebo, men who received zoledronic acid had fewer moderate-to-severe vertebral fractures (P=0.03) and less height loss (P=0.002). Fewer participants who received zoledronic acid had clinical vertebral or nonvertebral fractures, although this difference did not reach significance because of the small number of fractures. Bone mineral density was higher and bone-turnover markers were lower in the men who received zoledronic acid (P<0.05 for both comparisons). Results were similar in men with low serum levels of total testosterone. The zoledronic acid and placebo groups did not differ significantly with respect to the incidence of death (2.6% and 2.9%, respectively) or serious adverse events (25.3% and 25.2%). CONCLUSIONS: Zoledronic acid treatment was associated with a significantly reduced risk of vertebral fracture among men with osteoporosis. (Funded by Novartis Pharma; ClinicalTrials.gov number, NCT00439647.).

Impaired glucose metabolism in the heart of obese Zucker rats after treatment with phorbol ester.

OBJECTIVE: To investigate the influence of obesity on the regulation of myocardial glucose metabolism following protein kinase C (PKC) activation in obese (fa/fa) and lean (Fa/?) Zucker rats. DESIGN: Isolated hearts obtained from 17-week-old lean and obese Zucker rats were perfused with 200 nM phorbol 12-myristate 13-acetate (PMA) for different time periods prior to the evaluation of PKC and GLUT-4 translocation. For metabolic studies isolated hearts from 48 h starved Zucker rats were perfused with an erythrocytes-enriched buffer containing increased concentrations (10-100 nM) of PMA. MEASUREMENTS: Immunodetectable PKC isozymes and GLUT-4 were determined by Western blots. Glucose oxidation and glycolysis were evaluated by measuring the myocardial release of 14CO2 and 3H2O from [U-14C]glucose and [5-3H]glucose, respectively. RESULTS: PMA (200 nM) induced maximal translocation of ventricular PKCalpha from the cytosol to the membranes within 10 min. This translocation was 2-fold lower in the heart from obese rats when compared to lean rats. PMA also induced a significant translocation of ventricular GLUT-4 from the microsomal to the sarcolemmal fraction within 60 min in lean but not in obese rats. Rates of basal cardiac glucose oxidation and glycolysis in obese rats were approximately 2-fold lower than those of lean rats. Perfusion with increasing concentrations of PMA (10-100 nM) led to a significant decrease of cardiac glucose oxidation in lean but not in obese rats. CONCLUSION: Our results show that in the heart of the genetically obese Zucker rat, the impairment in PKCalpha activation is in line with a diminished activation of GLUT-4 as well as with the lack of PMA effect on glucose oxidation.

Nucleic acid-containing amyloid fibrils potently induce type I interferon and stimulate systemic autoimmunity.

The immunopathophysiologic development of systemic autoimmunity involves numerous factors through complex mechanisms that are not fully understood. In systemic lupus erythematosus, type I IFN (IFN-I) produced by plasmacytoid dendritic cells (pDCs) critically promotes the autoimmunity through its pleiotropic effects on immune cells. However, the host-derived factors that enable abnormal IFN-I production and initial immune tolerance breakdown are largely unknown. Previously, we found that amyloid precursor proteins form amyloid fibrils in the presence of nucleic acids. Here we report that nucleic acid-containing amyloid fibrils can potently activate pDCs and enable IFN-I production in response to self-DNA, self-RNA, and dead cell debris. pDCs can take up DNA-containing amyloid fibrils, which are retained in the early endosomes to activate TLR9, leading to high IFNα/β production. In mice treated with DNA-containing amyloid fibrils, a rapid IFN response correlated with pDC infiltration and activation. Immunization of nonautoimmune mice with DNA-containing amyloid fibrils induced antinuclear serology against a panel of self-antigens. The mice exhibited positive proteinuria and deposited antibodies in their kidneys. Intriguingly, pDC depletion obstructed IFN-I response and selectively abolished autoantibody generation. Our study reveals an innate immune function of nucleic acid-containing amyloid fibrils and provides a potential link between compromised protein homeostasis and autoimmunity via a pDC-IFN axis.

Comparative effects of losartan and irbesartan on serum uric acid in hypertensive patients with hyperuricaemia and gout.

OBJECTIVE: Losartan has been shown to increase urinary uric acid excretion and hence to lower serum uric acid levels. The purposes of the present study were: (1) to evaluate the effects of losartan on serum uric acid in hypertensive patients with hyperuricemia and gout, (2) to compare the effects of losartan with those of irbesartan, another angiotensin II receptor antagonist and (3) to evaluate whether losartan 50 mg b.i.d. has a greater impact on serum uric acid levels than losartan 50 mg once a day. METHODS: Thirteen hypertensive patients with hyperuricaemia and gout completed this prospective, randomized, double-blind, cross-over study. Uric acid-lowering drugs were stopped 3 weeks before the beginning of the study. Patients were randomized to receive either losartan 50 mg or irbesartan 150 mg once a day, for 4 weeks. During this phase, a placebo was given in the evening. After 4 weeks, the dose was increased to losartan 50 mg b.i.d., or irbesartan 150 mg b.i.d. for another 4 week period. Subsequently, the patients were switched to the alternative treatment modality. Enalapril (20 mg o.d.) was given during the run-in period and between the two treatment phases. Serum and urinary uric acid were measured at the beginning and at the end of each treatment phase. RESULTS: Our results show that losartan 50 mg once daily decreased serum uric acid levels from 538 +/- 26 to 491 +/- 20 micromol/l (P < 0.01). Irbesartan had no effect on serum uric acid. Increasing the dose of losartan from 50 mg o.d. to 50 mg twice a day, did not further decrease serum uric acid. This may in part be due to a low compliance to the evening dose as measured with an electronic device. Indeed, whatever the prescribed drug, the mean compliance of the evening dose was always significantly lower than that of the morning dose. The uricosuric effect of losartan appears to decrease with time when a new steady state of lower serum uric acid is reached. CONCLUSIONS: In contrast to irbesartan, losartan was uricosuric and decreased serum uric acid levels. Losartan 50 mg b.i.d. did not produce a greater fall in serum uric acid than losartan once a day. Losartan might be a useful therapeutic tool to control blood pressure and reduce serum uric acid levels in hypertensive patients with hyperuricaemia and gout.

Comparison of the metabolic and endocrine effects of 3,5,3'-triiodothyroacetic acid and thyroxine.

To test the hypothesis that 3,5,3'-triiodothyroacetic acid (Triac) is more active as a TSH suppressor than on peripheral parameters of thyroid hormone action, the following parameters were studied: basal metabolic rate, sleeping energy expenditure (SEE), sex hormone-binding globulin, and cholesterol. In a double blind trial, 14 subjects received during 3 weeks (phase 1) 180 micrograms T4 or 1700 micrograms Triac daily, divided into 3 doses, to suppress thyroidal secretion. The dosage was doubled for the next 3 weeks (phase 2). Under T4 treatment, TSH reached 0.11 mU/L during phase 1 and less than 0.03 mU/L during phase 2. With Triac, a marked TSH inhibition occurred after 1 week (0.17 mU/L), followed by an escape during the following 2 weeks (0.63 mU/L). During phase 2, an almost complete TSH suppression was obtained (0.03 mU/L). Both Triac doses suppressed endogenous thyroid hormone secretion, as evidenced by T4 and rT3 levels. Both substances induced a 2-fold stimulation of sex hormone-binding globulin during phase 2. Serum cholesterol decreased similarly, without affecting the high/low density lipoprotein ratio. T4 increased SEE by 4.1% and 8.5% during phases 1 and 2. Triac failed to induce the expected peripheral metabolic responses of the thyroid hormones, as demonstrated by an unchanged SEE and basal metabolic rate. These results clearly show a preferential action of Triac on TSH suppression.

Relationship between imatinib population pharmacokinetics and alpha-1-acid glycoprotein

Objectives: Considering the large inter-individual differences in the function of the systems involved in imatinib disposition, exposure to this drug can be expected to vary widely among patients. Among those known systems is alpha-1-acid glycoprotein (AGP), a circulating protein that strongly binds imatinib. This observational study aimed to explore the influence of plasma AGP on imatinib pharmacokinetics. Methods: A population pharmacokinetic analysis was performed using NONMEM based on 278 plasma samples from 51 oncologic patients, for whom both total imatinib and AGP plasma concentrations were measured. The influence of this biological covariate on oral clearance and volume of distribution was examined. Results: A one-compartment model with first-order absorption appropriately described the data. A hyperbolic relationship between plasma AGP levels and oral clearance, as well as volume of distribution was observed. A mechanistic approach was built up, postulating that only the unbound imatinib concentration was able to undergo first-order elimination through an unbound clearance process, and integrating the dissociation constant as a parameter in the model. This approach allowed determining an average (± SEM) free clearance of 1310 (± 172) L/h and a volume of distribution of 301 (± 23) L. By comparison, the total clearance previously determined was 14 (± 1) L/h. Free clearance was affected by body weight and pathology diagnosis. Moreover, this model provided consistent estimates of the association constant between imatinib and AGP (5.5?106 L/mol) and of the average in vivo free fraction of imatinib (1.1%). The variability observed (17% for free clearance and 66% for volume of distribution) was less than the one previously reported without considering AGP impact. AGP explained indeed about one half of the variability observed in total imatinib disposition. Conclusion: Such findings clarify in part the in vivo impact of protein binding on imatinib disposition and might raise again the question whether high levels of AGP could represent a resistance factor to imatinib. This remains however questionable, as it is not expected to affect free drug concentrations. On the other hand, would imatinib be demonstrated as a drug requiring therapeutic drug monitoring, either the measurement of free concentration or the correction of the total concentration by the actual AGP plasma levels should be considered for accurate interpretation of the results.

Fatty acid ketodienes and fatty acid ketotrienes: Michael addition acceptors that accumulate in wounded and diseased Arabidopsis leaves.

Physical damage and disease are known to lead to changes in the oxylipin signature of plants. We searched for oxylipins produced in response to both wounding and pathogenesis in Arabidopsis leaves. Linoleic acid 9- and 13-ketodienes (KODEs) were found to accumulate in wounded leaves as well as in leaves infected with the pathogen Pseudomonas syringae pv. tomato (Pst). Quantification of the compounds showed that they accumulated to higher levels during the hypersensitive response to Pst avrRpm1 than during infection with a Pst strain lacking an avirulence gene. KODEs are Michael addition acceptors, containing a chemically reactive alpha,beta-unsaturated carbonyl group. When infiltrated into leaves, KODEs were found to induce expression of the GST1 gene, but vital staining indicated that these compounds also damaged plant cells. Several molecules typical of lipid oxidation, including malonaldehyde, also contain the alpha,beta-unsaturated carbonyl reactivity feature, and, when delivered in a volatile form, powerfully induced the expression of GST1. The results draw attention to the potential physiological importance of naturally occurring Michael addition acceptors in plants. In particular, these compounds could act directly, or indirectly via cell damage, as powerful gene activators and might also contribute to host cell death.

Health effects of occupational exposure in a dairy food industry, with a specific assessment of exposure to airborne lactic acid bacteria

OBJECTIVE:: Lactic acid bacteria (LAB) are used in food industries as probiotic agents. The aim of this study is to assess the potential health effects of airborne exposure to a mix of preblend (LAB and carbohydrate) and milk powder in workers. METHODS:: A medical questionnaire, lung function tests, and immunologic tests were carried out on 50 workers. Occupational exposure to inhalable dust and airborne LAB was measured. RESULTS:: Workers not using respiratory masks reported more symptoms of irritation than workers using protection. Workers from areas with higher levels of airborne LAB reported the most health symptoms and the immune responses of workers to LAB was higher than the immune responses of a control population. CONCLUSIONS:: Measures to reduce exposure to airborne LAB and milk powder in food industries are recommended.