Has sclerostin a true endocrine metabolic action complementary to osteocalcin in older men?

UNLABELLED: The reported association between sclerostin and diabetes mellitus or abdominal fat may be biased by body size and bone mass. In older men, the association between serum sclerostin levels and metabolic syndrome lost significance after adjustment for bone mass. The association between sclerostin and energy metabolism needs further clarification. INTRODUCTION: Sclerostin is associated with abdominal fat, but this relationship may be biased since both are associated with body size and bone mass. Osteocalcin is a bone-derived hormone regulating energy metabolism. We assessed the association between serum sclerostin and metabolic syndrome (MetS) accounting for whole body mineral content (BMC) and osteocalcin. METHODS: We studied 694 men aged 51-85 who had serum osteocalcin and sclerostin measurements. RESULTS: Sclerostin was higher in 216 men with MetS compared with those without MetS (p < 0.005). Average sclerostin level increased significantly across the increasing number of MetS components. In multivariable models, higher sclerostin was associated with higher odds of MetS (odds ratio (OR) = 1.24/1 standard deviation (SD) increase [95 % confidence interval (95 % CI), 1.01-1.51]; p < 0.05). After further adjustment for BMC, the association of MetS with sclerostin lost significance, whereas that with osteocalcin remained significant. Men who were simultaneously in the highest sclerostin quartile and the lowest osteocalcin quartile had higher odds of MetS (OR = 2.14 [95 % CI, 1.15-4.18]; p < 0.05) vs. men being in the three lower sclerostin quartiles and three upper osteocalcin quartiles. After adjustment for whole body BMC, the association lost significance. CONCLUSIONS: Higher sclerostin level is associated with MetS severity; however, this association may be related to higher whole body BMC. The adjustment for BMC had no impact on the association between MetS and osteocalcin. Clinical cross-sectional studies do not elucidate the potential role of sclerostin in the regulation of energy metabolism and direct experimental approach is necessary.

[Identification of knowledge deficits of pharmacy students at the beginning of the fifth year of pharmacy practice experience: Proposals to change the content of academic programs]. / Identification des lacunes de connaissances des étudiants en filière officine débutant le stage de 5(e) année : propositions pour modifier le contenu de l'enseignement.

INTRODUCTION: In France, community pharmacy students performed a hospital pharmacy practice experience during the 5th year of the university curriculum. The purpose of a part of the content of the academic teaching program delivered before this practice experience is to prepare the students for their future hospital activities. It should enable them for the practical use of knowledge in order to improve pharmacotherapy, laboratory diagnosis and monitoring of patients' care. The aim of this study was to show if there are gaps in this program. METHODS: Fourteen students performing their clerkship in a teaching hospital were invited to highlight these gaps when they were gradually immersed in the pharmaceutical care. They did so under the careful observation of hospital pharmacist preceptors. These practitioners referred to professional guidelines, documentary tools used in daily clinical practice and publications supporting their pharmaceutical care practices. RESULTS: Shortcomings and gaps identified were: how to communicate with other healthcare professionals and the content of verbal exchanges, how to conduct a patient-centered consultation, documentation tools required for relevant pharmacist' interventions, codification of pharmacist's interventions, risks related to drug packaging and benefit risk assessment of health information technologies. DISCUSSION: These gaps represent a handicap by delaying the process that led to move from student to healthcare professional. Hospital pharmacist preceptors have to fill in these gaps before engaging students in pharmaceutical care. CONCLUSION: These results invite to revise partly the content of the academic teaching program delivered before the 5th year hospital pharmacy practice experience.

Nicotinic acid effects on insulin sensitivity and hepatic lipid metabolism: an in vivo to in vitro study.

Our aim was to characterize the effects and the underlying mechanisms of the lipid-regulating agent Niaspan(®) on both insulin action and triglyceride decrease in 20 nondiabetic, dyslipidemic men with metabolic syndrome receiving Niaspan(®) (2 g/day) or placebo for 8 weeks in a randomized, cross-over study. The effects on plasma lipid profile were characterized at the beginning and the end of each treatment period; insulin sensitivity was assessed using the 2-step euglycemic hyperinsulinemic clamp and VLDL-triglyceride turnover by measuring plasma glycerol enrichment, both at the end of each treatment period. The mechanism of action of nicotinic acid was studied in HuH7 and mouse primary hepatocytes. Lipid profile was improved after Niaspan(®) treatment with a significant-28% decrease in triglyceride levels, a+17% increase in HDL-C concentration and unchanged levels of fasting nonesterified fatty acid. VLDL-tri-glyceride production rate was markedly reduced after Niaspan(®) (-68%). However, the treatment induced hepatic insulin resistance, as assessed by reduced inhibition of endogenous glucose production by insulin (0.7±0.4 vs. 1.0±0.5 mg/kg · min, p<0.05) and decrease in fasting hepatic insulin sensitivity index (4.8±1.8 vs. 3.2±1.6, p<0.05) in the Niaspan(®) condition. Nicotinic acid also reduced insulin action in HuH7 and primary hepatocytes, independently of the activation of hepatic PKCε. This effect was associated with an increase in diacylglycerol and a decrease in tri-glyceride contents that occurred in the absence of modification of DGAT2 expression and activity. Eight weeks of Niaspan(®) treatment in dyslipidemic patients with metabolic syndrome induce hepatic insulin resistance. The mechanism could involve an accumulation of diacylglycerol and an alteration of insulin signaling in hepatocytes.

[Validation of pharmaceutical quality of a [6,6-(2)H(2)]-glucose parenteral solution used for insulin-resistance measurement during human clinical trials]. / Validation de la qualité pharmaceutique de préparations de [6,6-(2)H(2)]-glucose en solution aqueuse administrées par voie parentérale pour la mesure de l'insulino-résistance dans le cadre d'essais cliniques.

INTRODUCTION: Deuterated glucose ([6,6-(2)H(2)]-glucose) is a stable isotopic tracer administered parenterally in healthy volunteers, obese or diabetic patients in clinical trial to study glucose metabolism during euglycemic hyperinsulinemic clamps. In accordance with the Health Authorities on drug safety, we evaluated the pharmaceutical quality of this preparation for biomedical research with a stability study. METHODS: After pharmaceutical qualification of the raw material, the [6,6-(2)H(2)]-glucose was dissolved in water for injection, then sterile, filtered under positive pressure of nitrogen and then autoclaved. Two batch products (500mg/10mL and 2g/15mL) were sampled to evaluate glucose alteration, isotope shift, limpidity, apyrogenicity and sterility at regular intervals for 2 years. Deuterated glucose solutions were stored in the dark, at +2°C+8°C, in type II glass bottles. RESULTS: Neither significant decrease of glucose concentration nor pH variation were observed for 2 years. The 5-hydroxymethylfurfural concentration was below the human harmful levels, attesting a non-generation of metabolites during autoclaving. Isotopic enrichment higher than 99% reflected the stability of deuterated label on the 6-carbon of glucose molecules. The non-visible particle concentration below the minimal permissible concentration tolerated by the European Pharmacopoeia and the absence of bacterial endotoxin and bacterial growth attested limpidity, apyrogenicity and sterility of the [6,6-(2)H(2)]-glucose solutions. CONCLUSION: After the 2-year study, 500mg/10mL and 2g/15mL deuterated glucose solutions stored in the dark at +2°C+8°C were stable in aqueous solution, allowing to ensure safety administration for human clinical trials using euglycemic hyperinsulinemic clamps.

Time course of liver nitric oxide concentration in early septic shock by cecal ligation and puncture in rats.

An overwhelming nitric oxide (NO) production is a crucial step in the circulatory events as well as in the cellular alterations taking place in septic shock. However, evidences of this role arise from studies assessing the NO production on an intermittent basis precluding any clear evaluation of temporal relationship between NO production and circulatory alterations. We evaluated this relationship by using a NO specific electrode allowing a continuous measurement of NO production. Septic shock was induced by a cecal ligation and puncture (CLP) in a first group of anesthetized rats. After the same CLP, a second group received a selective iNOS inhibitor (L-NIL). Control rats were sham operated or sham operated with L-NIL administration. While NO concentration was measured every 2 min by a NO-sensitive electrode over 7h following CLP, the liver microcirculation was recorded by a laser-Doppler flowmeter. CLP induced a severe septic shock with hypotension occurring at a mean time of 240 min after CLP. At the same time, an increase in liver NO concentration was observed, whereas a decrease in microvascular liver perfusion was noted. In the septic shock group, L-NIL administration induced an increase in arterial pressure whereas the liver NO concentration returned to baseline values. In addition, shock groups experienced an increase in iNOS mRNA. These data showed a close temporal relationship between the increase in liver NO concentration and the microvascular alteration taking place in the early period of septic shock induced by CLP. The iNOS isoform is involved in this NO increase.

Effects of sodium nitroprusside on splanchnic microcirculation in a resuscitated porcine model of septic shock.

BACKGROUND: We tested the hypothesis that sodium nitroprusside (SNP) might improve the impairment of hepatosplanchnic microcirculatory blood flow (MBF) in septic shock. METHODS: Fourteen pigs were anaesthetized and their lungs mechanically ventilated. Sepsis was induced with i.v. infusion of live Pseudomonas aeruginosa [1x10(8) colony forming units (CFU) ml(-1) kg(-1)] for 1 h. Sixty minutes later, the animals received in a random succession either SNP or normal saline for 30 min. Mean arterial pressure (MAP), cardiac index (CI), mean pulmonary artery pressure (MPAP), carbon dioxide tension of the ileal mucosa (PCO2; by gas tonometry), ileal mucosal and hepatic MBF by laser Doppler flowmetry, blood gases, and lactates were assessed before, during administration, and 30 min after discontinuing the test drug. RESULTS: Bacterial infusion promoted hypodynamic shock (MAP -18%, CI -33%, ileal MBF -19%, and hepatic MBF -27%), which was converted to normodynamic shock by resuscitation. During SNP infusion, ileal mucosal MBF significantly increased (+19%) compared with control (P = 0.033). Although hepatic MBF increased (+42% from baseline), this did not differ from control. In order to maintain a constant central venous pressure and MAP, fluid loading and norepinephrine (P < 0.01) were increased. Acid-base status was not altered by SNP. CONCLUSIONS: In a resuscitated porcine model of the early phase of septic shock, SNP improved ileal mucosal MBF but required a concomitant increase in fluid and norepinephrine supplements to maintain constant systemic haemodynamic parameters.

[Inaccuracy of glucose meters. Automatic correction for hematocrit variations and the presence of exogenous interfering components]. / Inexactitude des lecteurs de glycémie. Correction automatique pour les variations de l'hématocrite et la présence d'interférents exogènes.

Seven hospital-based glucose monitoring systems (meters) were evaluated with particular attention to those analytical interferences encountered in intensive care patients. Imprecision differed little between meters and remained altogether within acceptable limits. Inaccuracy, as measured by comparison with a hexokinase method presented with significant differences, yet without exceeding acceptable limits either. All meters but one showed an important bias when hematocrit departed from the reference interval. Two meters would not distinguish maltose from glucose. Three showed an important positive bias in the presence of acetaminophen and four a comparable bias in the presence of ascorbate. Only one meter was unaffected by both such exogenous interferences and hematocrit variations, owing to built-in hematocrit and electrochemical blank measuring devices. This meter also showed narrowest correlation with hexokinase methods. At a time when intensive care patients are being submitted to ever tighter glycemic control, it is desirable and our results show that it is now possible to tighten accordingly the acceptability criteria of glucose meters used to this end.

[Fatty acids regulate NOX activity]. / Régulation de l'activité des NADPH oxydases en présence d'acides gras.

NADPH oxidase (NOX) is a multimeric enzyme including a catalytic unit, gp91(phox), and several regulating subunits: p22(phox), p40(phox), p47(phox), p67(phox). This enzyme, also known as flavocytochrome b(588), is responsible for a deliberate production of superoxyde anion (O2*-). This enzyme, initially described in polynuclear neutrophils (NOX 2), belongs to a complex family of multimeric isoenzymes whose members are present in many cell types. NOXs are generally associated to cell signaling and they seem involved in physiological phenomena (vascular reactivity, proliferation and cellular migration...) as well as in many diseases. Lipids in general and poly unsaturated fatty acids (PUFA) in particular are able to modulate the activity of NOX in many models. With our fibroblastic model, we show that only arachidonic acid (AA) is able to activate the enzyme directly whereas many PUFA are able to induce a production of reactive oxygen species (ERO). Moreover the decrease of ERO production and NOX activity in fibroblasts triggered by PUFA does not depend on SOD activity but the time course of this decrease is associated with the expression of heme oxygenase 1 (HO-1). Besides a regulation by protein subunits, we propose, according to this model, a loop of regulation of NOX activity including a stimulation by lipids associated with an inhibition by HO-1. Thus, lipids, by interaction with phospholipase A2, release arachidonic acid which stimulates NOX, amplifying superoxyde anion production. This oxygen species may induce redox-sensitive gene transcription such as HO-1. Consequently this enzyme inhibits NOX activity and limits superoxyde anion production by heme degradation and CO production.

Increased lactate/pyruvate ratio with normal beta-hydroxybutyrate/acetoacetate ratio and lack of oxygen supply dependency in a patient with fatal septic shock.

We report a case of fatal septic shock, with hyperlactatemia and blood cultures positive for Streptococcus pneumoniae, in a 70-year-old patient. On two occasions (5 days, and 2 days before the patient's death), the relationship between oxygen delivery (DO2) and consumption (VO2) was examined in conjunction with two presumed markers of tissue oxygenation: the lactate/pyruvate ratio (L/P), and the beta-hydroxybutyrate acetoacetate ratio (beta OHB/AcAc). Increasing DO2 by about 30% ("oxygen flux test") failed to increase VO2. The beta OHB/AcAc ratio remained within normal limits, thus suggesting uncompromised tissue oxygenation at the hepatic level. The L/P ratio remained persistently above normal limits, thus suggesting actual organ or regional hypoxia. This case shows that during an overwhelming septic shock, the "oxygen flux test" can be negative, despite the presence of hyperlactatemia and of an increased L/P ratio suggestive of impaired tissue oxygenation.

Time course of oxidative stress after major burns.

OBJECTIVE: To evaluate oxidative stress resulting from major burns in humans. DESIGN: Prospective clinical study with control group. SETTING: Mechanically ventilated adult patients admitted with more than 30% total burn surface area. PATIENTS AND PARTICIPANTS: 20 patients with a mean body surface burned area of 54%. MEASUREMENTS AND RESULTS: The oxidative stress evaluation was based on measurements of trace elements, vitamins, antioxidant enzymatic activity and end-products of lipid peroxidation. During the first 5 days after injury burn patients exhibit a decrease in selenium and antioxidant vitamins (C, beta-carotene, lycopene) and an increase in lipid peroxidation products (TBARS). CONCLUSION: Our results suggest that major burn is associated with oxidative stress during the 5 days after the initial injury, as demonstrated by a simultaneous decrease in antioxidant vitamins and a large increase in TBARS.

[Considerations on delocalized HbA1c assays]. / Réflexions sur les dosages délocalisés d'hémoglobine A1C.

Availability and knowledge of HbA(1c) value during consultation is an important feature for diabetologists, that permits a better adaptation of therapy and a better motivation of patients. This expectation explains the request for delocalized assays of HbA(1c), even though life prognosis is not affected, like in the other cases of point of care testing. One of the most frequent solutions is the use of immunological delocalized HbA(1c) assays. Technically, these methods have to meet the same criteria as those used in laboratories. They have to be standardized, and controlled according to the "Guide de Bonne Exécution des Analyses de Biologie Médicale" (GBEA) rules. Solutions chosen for delocalization must respect specific skills of clinicians and biologists and cope with cost limitations. This paper reviews rationales for delocalized HbA(1c) assays, steps of their implementation, and their use in practical routine, with a special emphasis given on the necessary complementarity between clinicians and biologists.

[Optimisation of the measurement of nitrite and nitrate in serum by the Griess reaction]. / Optimisation des paramètres du dosage des nitrites et nitrates sériques par la technique de Griess.

Nitrite (NO2-) and nitrate (NO3-) concentrations are usually measured as a marker of NO metabolism. Indeed, this radical plays an important role in a lot of pathological processes. The aim of this study was to validate and standardize a method for the quantification of these two metabolites in serum. The most commonly method involved to determine nitrite and nitrate is the Griess reaction. From the different methods which are reported in literature, we tested several parameters to define operating conditions: the samples were deproteinized with zinc sulfate and reduced with cadmium granules. Analytical recovery of NO3- added to serum samples after reduction was 99.6% +/- 3.2% (n = 4). Within-run precision was 6.1% (n = 17) and between-day precision was 6.6% (n = 12). Usual values were determined from healthy fasted subjects: the mean concentration of NO2- and NO3- was 47.8 muM +/- 15.7 muM (n = 25). The detection limit of the assay was 1.3 muM and the quantitation limit was 2.5 muM. We tested also an HPLC method. However, it was not possible to use it from a biological matrice.

[Measurement of peroxidase activity with orthophenylenediamine as chromogen in immunoenzyme methods]. / Mesure de l'activité peroxydasique avec l'orthophénylènediamine comme chromogène dans les méthodes enzymo-immunologiques.

The authors studied orthophenylenediamine in order to determine the optimal conditions for its use in "sandwich" type of enzymo-immunology. They studied the kinetics of the reaction and the stopping of the enzymatic reaction in the presence of peroxidase-labeled antibody. Studies of the dissolution of orthophenylenediamine and the stability of the solutions obtained show that a solution of orthophenylenediamine can be stored at ambiant temperature and in darkness for 8 hours. Depending on the degree of sensitivity required, the concentration of orthophenylenediamine can vary between 10 to 30 mmol/l with 10 mmol/l of H2O2. Stopping the reaction with acid greatly increases the values of absorbance by 1.5 to 3 times, depending on the type of acid used. The tests demonstrated that the sensitivity and repeatability are better than can be obtained with 2,2' azino-di(3-ethylbenzthiazoline-6-sulfonic) acid. On the basis of these experiments, orthophenylenediamine was used in the assay of ferritin and total IgE: the increased sensitivity meant that the amount of antigen introduced into the reaction could be reduced to 1/5 of the amount usually required.

[Measurement of total bile acids. Comparison of different preparations of 3 alpha-hydroxysteroid dehydrogenase]. / Dosage des acides biliaires totaux. Comparaison de différentes préparations de 3 alpha-hydroxystéroïde déshydrogénase.

Oxidation of free and conjugated biliary acids was carried out with 5 different enzymatic preparations of 3 alpha-hydroxysteroid dehydrogenase. The comparison of the catalytic activities obtained, shows the existence of important variations according to the enzymes. Preparations purified by chromatography have a stronger activity toward primary biliary acids than toward secondary biliary acids, while preparations obtained from bacterial mutants have a low activity toward cholic acid and its conjugates.

[Description of the processes involved in the control of point-of-care testing]. / Description des processus impliqués dans la maîtrise des examens de biologie médicale délocalisés.

Compliance to EN ISO 22870 standard for point-of-care testing (POCT) accreditation is close to those of EN ISO 15189 in central laboratory. However, it is mandatory to master the elements which are specific to POCT. In this paper, we describe the two main processes involved to help medical biologists to achieve standard requirements, particularly in the risk assessment study. The first process concerns the deployment of a POCT device in a hospital outside laboratory and the second is the classical process of medical biology testing, outlining the steps which are different from the laboratory testing process. Furthermore, we reference, in front of each sub-process described, the different articles published in the present volume detailing specific guidelines to master them.

[Guidelines for the formation of a multidisciplinary group for point-of-care testing supervision according to EN ISO 22870]. / Recommandations pour la constitution d'un groupe d'encadrement des examens de biologie médicale délocalisés.

EN ISO 22870 requires the medical laboratory director to form a multidisciplinary group for the management of point-of-care testing activities and to appoint a person responsible for this group. This article proposes to define the composition (representatives of the medical laboratory, care units owning point-of-care devices, administration), missions (introduction, follow-up and evaluation of point-of-care devices) and the decision circuit of this group and to describe the profile of the head and the tasks assigned.

[Guidelines for documentation management mastery according to the EN ISO 22870]. / Recommandations pour la gestion documentaire des examens de biologie médicale délocalisés.

This article proposes to organize the documentation system of point-of-care testing (POCT) to meet the requirements of EN ISO 22870. In a first part, we propose provisions to improve the control of documents circulating outside the laboratory and aimed at non-laboratory staff. Then we review POCT-related records and we propose an organization facilitating their audit. In the last part, a model of POCT quality plan is proposed : in addition to the quality manual, this document defines the specific measures taken in order to ensure the control of POCT.

[Guidelines for the management of point-of care testing pre-examination, examination and post-examination phases according to the EN ISO 22870 standard]. / Recommandations pour la maîtrise des phases pré-analytique et analytique des examens de biologie médicale délocalisés.

Quality of point-of-care examinations depends on the quality assurance system settled. This paper describes the different tools used to control the pre-examination, examination and post-examination procedures taking part in the quality of patient care according to the requirements of the standard EN ISO 22870 and EN ISO 15189 as well. They include mainly: For the pre-examination phase, the sample traceability and for the analytical phase, the practice of internal quality control and the participation in external quality assessment programme.

Serum level of the phosphaturic factor FGF23 is associated with abdominal aortic calcification in men: the STRAMBO study.

CONTEXT: Calcification inhibitor deficiencies, mineral imbalance, and phenotypic transformation of vascular cells to osteogenic cells initiate and sustain vascular calcification. Fibroblast growth factor-23 (FGF23) is a key molecule regulating mineral homeostasis. OBJECTIVE: Our objective was to assess the association of serum FGF23 levels with mineral metabolism parameters and abdominal aortic calcification (AAC) in men. DESIGN: This was a cross-sectional analysis in the STRAMBO cohort. SETTING: Men holding a private health insurance cover with Mutuelle de Travailleurs de la Région Lyonnaise were included in the study. PARTICIPANTS: Participants included male volunteers aged 20-87 (n = 1130). INTERVENTIONS: Nonfasting blood collection was done. AAC was semiquantitatively assessed from vertebral fracture assessment scans obtained using dual-energy x-ray absorptiometry. MAIN OUTCOME MEASURES: We evaluated the association between FGF23 concentration and AAC severity in men. RESULTS: In 350 men aged 60 yr or younger, FGF23 levels decreased with age (r = -0.21; P < 0.001) but were not associated with any other parameter. In 780 men aged over 60 yr, serum FGF23 correlated with age (r = 0.37; P < 0.001) and, after adjustment for confounders, with glomerular filtration rate (r = -0.31; P < 0.001) and PTH levels (r = 0.25; P < 0.001). After adjustment for confounders, self-reported ischemic heart disease, diabetes mellitus as well as higher concentrations of C-reactive protein and osteoprotegerin were all associated with higher FGF23 levels. After adjustment for confounders, subjects in the highest FGF23 quartile had higher prevalence of severe AAC compared with the three lower quartiles combined (odds ratio = 1.88; 95% confidence interval = 1.22-2.85; P < 0.005). CONCLUSIONS: In healthy older men, circulating FGF23 is associated with parameters of mineral metabolism, including bone metabolism-regulating cytokines, and with severe AAC independent of traditional risk factors.