Evolution du degré d'activité de la maladie à l'introduction et après 1 an de traitement biologique chez les patients souffrant de polyarthrite rhumatoïde en Suisse

Introduction. - En Suisse, la prescription de produits biologiqueschez les patients souffrant de polyarthrite rhumatoïde (PR) n'est nilimitée à des centres hospitaliers de rhumatologie, ni soumise à desdirectives strictes éditées par les autorités sanitaires sur le type oule nombre de traitements de fond préalables. La notion d'échec auxtraitements de fond n'est pas non plus précisément définie, et enparticulier l'activité de la maladie ne doit pas répondre à des critèresstricts, notamment en terme de valeurs de DAS, et ce contrairementà de nombreux autres pays où l'impact de ces restrictions aété publié récemment (1, 2).Le registre SCQM peut être considéré comme un bon reflet de lapopulation suisse avec PR, aussi bien pour la population suivie pardes centres hospitaliers que par les practiciens en cabinet privé, eton estime qu'environ 30 % des patients avec PR recevant des traitementsbiologiques en Suisse sont inclus dans ce registre.L'objectif primaire de cette étude est de comparer les caractéristiquesdes patients de notre registre à l'initiation et après un an de traitementbiologique avec celles de registres du même type dans des pays avecun accès plus restreint aux traitements biologiques. Les objectifssecondaires sont de comparer les patients traités en milieu hospitalieret ceux pris en charge en cabinet privé, et aussi d'examiner s'il existedes tendances temporelles (avant et après 2005).Patients et Méthodes. - Les données sont extraites du registre suissede PR (SCQM) qui comprend 4 500 patients inclus entre 1997 et2011. 2 715 patients bénéficient d'un traitement biologique, dont2 427 avec des données à l'introduction du traitement : DAS28/VS,DAS28/CRP, HAQ, durée de la maladie, nbre de tttt préalables, comorbidités,etc. Les principales données démographiques sont : âgemoyen 55 ans, 77 % de femmes 72 % FR+, médecins prescripteurs :62 % en cabinet, 21 % en centre hospitaliers et 16 % en centres universitaires.Nous avons calculés les moyennes (+/- écart type) pourdifférents paramètres de l'activité de la maladie.Résultats. - La moyenne du DAS28/VS à l'introduction du traitement(4,4 +/- 1,3) est nettement inférieur aux valeurs publiées pard'autres registres européens ou canadien (5,3 < > 6,6 ; 1,2). Il en ende même pour le HAQ (1 versus 1,4). Les biologiques sont introduitsaprès en moyenne 1,1 +/- 1 DMARD préalable contre > 3 en Suède,au Danemark ou au Canada.Les caractéristiques démographiques, le degré d'activité et les traitementsprodigués sont similaires entre les patients traités encabinet privé ou en milieu hospitalier, hormis pour une proportionmoindre de traitements iv en cabinet (20 % versus 40 %). Après2005, les traitements biologiques sont introduits beaucoup plusprécocemment, avec une durée médiane de maladie avant l'introductionde thérapies biologiques diminuant de 96 à 51 mois. Onnote également une répartition entre les divers produits biologiquesqui se diversifie. Même si les traitements sont introduits à undegré d'activité similaire (DAS28/VS moyen à 4,4 +/- 1,3) onobserve de meilleurs résultats à 1 an avec un DAS moyen à 1 an :3,5 +/- 1,4 avant 2005 contre 3,1 +/- 1,3 après 2005 (p = 0.0001).Conclusion. - Les données du registre suisse des PR (SCQM) suggèrentque, en l'absence de critères restrictifs d'accès aux traitements biologiques,ceux-ci sont prescrits à des scores d'activité de la maladie(DAS et HAQ) inférieurs, et plus précocemement en terme de nombrede DMARD préalables. Cette tendance se confirme dans le temps, etse retrouve aussi bien en milieu hospitalier qu'en cabinet.En terme de résultats, après 2005, plus de 50 % des patients atteignentun bas degré d'activité de la maladie en terme de DAS aprèsun an de traitement, chiffre qui semble justifier ce type de systèmepeu restrictif favorisant certainement une approche thérapeutiqueplus proche des nouveaux paragidmes de traitement avec une stratégiede type « treat to target ».Références[1] Curtis J R et al. Semin Arthritis Rheum. 40:2-14,2009.[2] Pease C, Pope JE, Truong D et al. Semin Arthritis Rheum, December2010.

Quality Assessment of Cardiac Magnetic Resonance Images at 1.5/3.0 T: Description and Validation of Standardized Criteria

PURPOSE: Cardiovascular magnetic resonance (CMR) has become a robust and important diagnostic imaging modality in cardiovascular medicine. However,insufficient image quality may compromise its diagnostic accuracy. No standardized criteria are available to assess the quality of CMR studies. We aimed todescribe and validate standardized criteria to evaluate the quality of CMR studies including: a) cine steady-state free precession, b) delayed gadoliniumenhancement, and c) adenosine stress first-pass perfusion. These criteria will serve for the assessment of the image quality in the setting of the Euro-CMR registry.METHOD AND MATERIALS: First, a total of 45 quality criteria were defined (35 qualitative criteria with a score from 0-3, and 10 quantitative criteria). Thequalitative score ranged from 0 to 105. The lower the qualitative score, the better the quality. The quantitative criteria were based on the absolute signal intensity (delayed enhancement) and on the signal increase (perfusion) of the anterior/posterior left ventricular wall after gadolinium injection. These criteria were then applied in 30 patients scanned with a 1.5T system and in 15 patients scanned with a 3.0T system. The examinations were jointly interpreted by 3 CMR experts and 1 study nurse. In these 45 patients the correlation between the results of the quality assessment obtained by the different readers was calculated.RESULTS: On the 1.5T machine, the mean quality score was 3.5. The mean difference between each pair of observers was 0.2 (5.7%) with a mean standarddeviation of 1.4. On the 3.0T machine, the mean quality score was 4.4. The mean difference between each pair of onservers was 0.3 (6.4%) with a meanstandard deviation of 1.6. The quantitative quality assessments between observers were well correlated for the 1.5T machine: R was between 0.78 and 0.99 (pCONCLUSION: The described criteria for the assessment of CMR image quality are robust and have a low inter-observer variability, especially on 1.5T systems.CLINICAL RELEVANCE/APPLICATION: These criteria will allow the standardization of CMR examinations. They will help to improve the overall quality ofexaminations and the comparison between clinical studies.

Induction of transendothelial migration in normal and malignant human T lymphocytes.

Activated CD 3+ enriched human peripheral blood T cells exhibited potent capacity for transendothelial migration through HUVEC layers in the absence of T cell ***. In contrast, malignant human T cell lines *** no or negligible ability of transendothelial migration in the absence of chemoattractants. Time lapse studies of transendothelial migration of activated CD 3+ enriched peripheral blood T cells through a HUVEC layer showed that the first T cells were detected in the lower compartment of a tissue culture insert after 1 hour and that migration increased to reach a maximum of 25 x 10(4) T cells/hr after 24 hours. Adhesion assays of human T cell lines demonstrated that all T cell lines were capable of adhesion to HUVEC and that adhesion of T cells to HUVECs was primarily mediated by CD11a/CD18 and ICAM-1 interactions. Furthermore, transendothelial migration of CD 3+ enriched human peripheral blood T cells was inhibited by pretreating the T cells with anti-CD 18 monoclonal antibodies. The inability of malignant T cells to migrate through HUVEC layers in the absence of chemoattractants was not due to poor motility per se, since both normal and malignant T cells migrated well on extracellular matrix components as determined by using Boyden chambers. Crosslinking of alpha 1 beta 2 and alpha 4 beta 1 with immobilized monoclonal antibodies induced motile behaviour in activated CD 3 enriched human peripheral blood T cells but not in malignant T cell lines. In conclusion, the differences in the ability of transendothelial migration between normal and malignant human T cells in the absence of chemoattractants is primarily due to the differences in the capacity of alpha 1 beta 2 and alpha 4 beta 1 to trigger motile behaviour in the separate cell types.

Disease activity in rheumatoid arthritis patients at initiation of biologic agents and 1 year of treatment: results from the Swiss SCQM registry.

OBJECTIVE: In Switzerland, the prescription of biologic antirheumatic agents in rheumatoid arthritis (RA) patients is not limited by stringent requirements from health authorities. The goals of this study were to: determine the characteristics of the Swiss patients at the initiation of biologics, compare them with other countries and evaluate whether different disease activity levels at initiation of therapy, resulting from distinct access to these treatment, influence their effectiveness. METHODS: This is a retrospective cohort study of RA patients followed in the Swiss register (SCQM-RA). Two thousand and sixty patients treated with biologics were retrieved. We present the disease characteristics and the patients' demographic data, at initiation and some effectiveness data after 1 year of treatment. RESULTS: Two thousand and sixty patients treated with biologics were retrieved. At initiation of treatment, the mean disease activity DAS (SD): 4.4 (1.4), number of previous antirheumatic treatments: 1.1, functional status HAQ: 1.1 (0.7) and median duration of illness: 5.5 years were significantly lower than in other published registries. The mean DAS: 3.3 (1.4) 1 year after initiation of therapy also appears lower than in other countries. Additionally, patients treated more recently (after 2005) had a significantly higher improvement in mean DAS. CONCLUSIONS: Data from the Swiss RA registry demonstrate that biologics are prescribed at a lower level of disease activity and after fewer prior DMARD failures than in most other countries, a practice that seems to correlate with overall lower absolute levels of disease activity and better patient outcomes after 1 year of treatment.

An ultra performance liquid chromatography-tandem MS assay for tamoxifen metabolites profiling in plasma: first evidence of 4'-hydroxylated metabolites in breast cancer patients.

There is increasing evidence that the clinical efficacy of tamoxifen, the first and most widely used targeted therapy for estrogen-sensitive breast cancer, depends on the formation of the active metabolites 4-hydroxy-tamoxifen and 4-hydroxy-N-desmethyl-tamoxifen (endoxifen). Large inter-individual variability in endoxifen plasma concentrations has been observed and related both to genetic and environmental (i.e. drug-induced) factors altering CYP450s metabolizing enzymes activity. In this context, we have developed an ultra performance liquid chromatography-tandem mass spectrometry method (UPLC-MS/MS) requiring 100 μL of plasma for the quantification of tamoxifen and three of its major metabolites in breast cancer patients. Plasma is purified by a combination of protein precipitation, evaporation at room temperature under nitrogen, and reconstitution in methanol/20 mM ammonium formate 1:1 (v/v), adjusted to pH 2.9 with formic acid. Reverse-phase chromatographic separation of tamoxifen, N-desmethyl-tamoxifen, 4-hydroxy-tamoxifen and 4-hydroxy-N-desmethyl-tamoxifen is performed within 13 min using elution with a gradient of 10 mM ammonium formate and acetonitrile, both containing 0.1% formic acid. Analytes quantification, using matrix-matched calibration samples spiked with their respective deuterated internal standards, is performed by electrospray ionization-triple quadrupole mass spectrometry using selected reaction monitoring detection in the positive mode. The method was validated according to FDA recommendations, including assessment of relative matrix effects variability, as well as tamoxifen and metabolites short-term stability in plasma and whole blood. The method is precise (inter-day CV%: 2.5-7.8%), accurate (-1.4 to +5.8%) and sensitive (lower limits of quantification comprised between 0.4 and 2.0 ng/mL). Application of this method to patients' samples has made possible the identification of two further metabolites, 4'-hydroxy-tamoxifen and 4'-hydroxy-N-desmethyl-tamoxifen, described for the first time in breast cancer patients. This UPLC-MS/MS assay is currently applied for monitoring plasma levels of tamoxifen and its metabolites in breast cancer patients within the frame of a clinical trial aiming to assess the impact of dose increase on tamoxifen and endoxifen exposure.

Variations in IB1/JIP1 expression regulate susceptibility of beta-cells to cytokine-induced apoptosis irrespective of C-Jun NH2-terminal kinase signaling.

We previously reported that interleukin-1beta (IL-1beta) alone does not cause apoptosis of beta-cells, whereas when combined with gamma-interferon (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha), it exerts a distinct apoptotic effect. Studies in beta-cell lines indicated that IL-1beta reduced expression of islet brain (IB)-1/JNK interacting protein (JIP)-1, a JNK scaffold protein with antiapoptotic action. We examined whether variations in IB1/JIP-1 expression in purified primary beta-cells affect their susceptibility to cytokine-induced apoptosis. Exposure to IL-1beta for 24 h decreased cellular IB1/JIP-1 content by 66 +/- 17%; this IL-1beta effect was maintained in the presence of TNF-alpha + IFN-gamma, which did not influence IB1/JIP-1 levels by themselves. Addition of IL-1beta to TNF-alpha + IFN-gamma increased apoptosis from 20 +/- 2% to 59 +/- 5%. A similar increase in TNF-alpha + IFN-gamma-induced apoptosis was produced by adenoviral expression of antisense IB1/JIP-1 and was not further enhanced by addition of IL-1beta, indicating that IL-1beta-mediated suppression of IB1/JIP-1 in beta-cells increases their susceptibility to cytokine-induced apoptosis. However, adenovirally mediated overexpression of IB1/JIP-1 also potentiated TNF-alpha + IFN-gamma-induced apoptosis, suggesting that the antiapoptotic effect of IB1/JIP-1 depends on well-defined cellular levels. We conclude that the IB1/JIP-1 level in beta-cells can control their susceptibility to apoptosis independent of JNK signaling.

Glutamine Stimulates Biosynthesis and Secretion of Insulin-like Growth Factor 2 (IGF2), an Autocrine Regulator of Beta Cell Mass and Function.

IGF2 is an autocrine ligand for the beta cell IGF1R receptor and GLP-1 increases the activity of this autocrine loop by enhancing IGF1R expression, a mechanism that mediates the trophic effects of GLP-1 on beta cell mass and function. Here, we investigated the regulation of IGF2 biosynthesis and secretion. We showed that glutamine rapidly and strongly induced IGF2 mRNA translation using reporter constructs transduced in MIN6 cells and primary islet cells. This was followed by rapid secretion of IGF2 via the regulated pathway, as revealed by the presence of mature IGF2 in insulin granule fractions and by inhibition of secretion by nimodipine and diazoxide. When maximally stimulated by glutamine, the amount of secreted IGF2 rapidly exceeded its initial intracellular pool and tolbutamide, and high K(+) increased IGF2 secretion only marginally. This indicates that the intracellular pool of IGF2 is small and that sustained secretion requires de novo synthesis. The stimulatory effect of glutamine necessitates its metabolism but not mTOR activation. Finally, exposure of insulinomas or beta cells to glutamine induced Akt phosphorylation, an effect that was dependent on IGF2 secretion, and reduced cytokine-induced apoptosis. Thus, glutamine controls the activity of the beta cell IGF2/IGF1R autocrine loop by increasing the biosynthesis and secretion of IGF2. This autocrine loop can thus integrate changes in feeding and metabolic state to adapt beta cell mass and function.

Tubular Dysfunction in Idiopathic Nephrotic Syndrome

Objectives: To evaluate the degree of tubular involvement in INS at various stage of the disease. Methods: 19 patients with INS were studied. 13 were steroid responders (group 1). 5 of them had biopsy which showed MCD. 6 patients were non responder to steroid or were steroid dependant with frequent relapses (group 2). Biopsies showed 3 FSGS and 3 MCD. They were treated with prednisone, ciclosporin and/ or mycofenolate mofetil. Protein, microalbumin (ALB), alpha-microglobulin (AMG), N-acetyl-beta-D-glucosaminidase (NAG) and creatinine (cr) were measured in each urine sample. Patients were considered in remission if prot/ cr ratio (g/mol) was < 20 (group 1a and 2a), and in relapse if the ratio was > 200 (group 1c and 2c). Some patients in group 1 had non nephrotic proteinuria (group 1b). Tubular dysfunction was defi ned by NAG/cr ratio (mg/mmol) > 0.86 or by AMG/cr ratio (mg/mmol) > 1.58. Results: Prot/cr ALB/cr NAG/cr AMG/cr Group 1a 10.3 ± 4.1 1.1 ± 1.0 0.19 ± 0.12 1.40 ± 0.97 Group 1b 60.4 ± 63.4 42.8 ± 66.7 0.39 ± 0.21 1.20 ± 0.56 Group 1c 713.3 ± 276.8 799.8 ± 534.9 2.25 ± 1.86* 4.25 ± 2.09* Group 2a 11.3 ± 6.1 4.7 ± 5.7 0.26 ± 0.19 1.18 ± 0.60 Group 2c 914.9 ± 718.6 682.9 ± 589.3 3.00 ± 2.72* 5.47 ± 4.30* Results are mean ± SD, p < 0.001 compared to group 1a and 2a No difference was observed between group 1 and group 2 neither in remission nor in relapse. Conclusions: These data indicate that tubular dysfunction occurs in INS but only in patients in relapse. In this population, tubular dysfunction was independent of the severity of the nephrotic syndrome, the treatment protocol and the histopathology.

Manganese-induced integrin affinity maturation promotes recruitment of alpha V beta 3 integrin to focal adhesions in endothelial cells: evidence for a role of phosphatidylinositol 3-kinase and Src.

Integrin activity is controlled by changes in affinity (i.e. ligand binding) and avidity (i.e. receptor clustering). Little is known, however, about the effect of affinity maturation on integrin avidity and on the associated signaling pathways. To study the effect of affinity maturation on integrin avidity, we stimulated human umbilical vein endothelial cells (HUVEC) with MnCl(2) to increase integrin affinity and monitored clustering of beta 1 and beta 3 integrins. In unstimulated HUVEC, beta 1 integrins were present in fibrillar adhesions, while alpha V beta 3 was detected in peripheral focal adhesions. Clustered beta 1 and beta 3 integrins expressed high affinity/ligand-induced binding site (LIBS) epitopes. MnCl(2)-stimulation promoted focal adhesion and actin stress fiber formation at the basal surface of the cells, and strongly enhanced mAb LM609 staining and expression of beta 3 high affinity/LIBS epitopes at focal adhesions. MnCl(2)-induced alpha V beta 3 clustering was blocked by a soluble RGD peptide, by wortmannin and LY294002, two pharmacological inhibitors of phosphatidylinositol 3-kinase (PI 3-K), and by over-expressing a dominant negative PI 3-K mutant protein. Conversely, over-expression of active PI 3-K and pharmacological inhibiton of Src with PP2 and CGP77675, enhanced basal and manganese-induced alpha V beta 3 clustering. Transient increased phosphorylation of protein kinase B/Akt, a direct target of PI 3K, occurred upon manganese stimulation. MnCl(2) did not alter beta 1 integrin distribution or beta1 high-affinity/LIBS epitope expression. Based on these results, we conclude that MnCl(2)-induced alpha V beta 3 integrin affinity maturation stimulates focal adhesion and actin stress fiber formation, and promotes recruitment of high affinity alpha V beta 3 to focal adhesions. Affinity-modulated alpha V beta 3 clustering requires PI3-K signaling and is negatively regulate by Src.

A novel dominant mutation of the Nav1.4 alpha-subunit domain I leading to sodium channel myotonia.

BACKGROUND: Mutations in SCN4A may lead to myotonia. METHODS: Presentation of a large family with myotonia, including molecular studies and patch clamp experiments using human embryonic kidney 293 cells expressing wild-type and mutated channels. RESULTS: In a large family with historic data on seven generations and a clear phenotype, including myotonia at movement onset, with worsening by cold temperature, pregnancy, mental stress, and especially after rest after intense physical activity, but without weakness, the phenotype was linked with the muscle sodium channel gene (SCN4A) locus, in which a novel p.I141V mutation was found. This modification is located within the first transmembrane segment of domain I of the Na(v)1.4 alpha subunit, a region where no mutation has been reported so far. Patch clamp experiments revealed a mutation-induced hyperpolarizing shift (-12.9 mV) of the voltage dependence of activation, leading to a significant increase (approximately twofold) of the window current amplitude. In addition, the mutation shifted the voltage dependence of slow inactivation by -8.7 mV and accelerated the entry to this state. CONCLUSIONS: We propose that the gain-of-function alteration in activation leads to the observed myotonic phenotype, whereas the enhanced slow inactivation may prevent depolarization-induced paralysis.

Inflammatory caspases in innate immunity and inflammation.

Caspases are best known for their role in apoptosis. More recently, they have gained prominence as critical mediators of innate immune responses. The so-called 'inflammatory caspases' include human caspase-1, -4, -5 and -12 and murine caspase-1, -11 and -12. Of these, caspase-1 is best characterized and serves as the prototype for our understanding of the processing, activation and function of inflammatory caspases. Like their apoptotic counterparts, inflammatory caspases are produced as inactive zymogens and require activation to become proteolytically active. Caspase-1 is activated within the inflammasome, a large cytosolic protein complex that is induced by a growing number of endogenous, microbial, chemical or environmental stimuli. The importance of caspase-1 in initiating innate immune responses is demonstrated by its role in cleaving pro-IL-1 beta and pro-IL-18 to their biologically active forms. New functions have also been implicated, as these proteases and the mechanisms underlying their activation and regulation emerge as important mediators of human health and disease.

Infrequent transmission of HIV-1 drug-resistant variants.

Transmission of drug-resistant variants is influenced by several factors, including the prevalence of drug resistance in the population of HIV-1-infected patients, HIV-1 RNA levels and transmission by recently infected patients. In order to evaluate the impact of these factors on the transmission of drug-resistant variants, we have defined the population of potential transmitters and compared their resistance profiles to those of newly infected patients. Sequencing of pol gene was performed in 220 recently infected patients and in 373 chronically infected patients with HIV-1 RNA >1000 copies/ml. Minimal and maximal drug-resistance profiles of potential transmitters were estimated by weighting resistance profiles of chronically infected patients with estimates of the Swiss HIV-1-infected population, the prevalence of exposure to antiviral drugs and the proportion of infections attributed to primary HIV infections. The drug-resistance prevalence in recently infected patients was 10.5% (one class drug resistance: 9.1%; two classes: 1.4%; three classes: 0%). Phylogenetic analysis revealed significant clustering for 30% of recent infections. The drug-resistance prevalence in chronically infected patients was 72.4% (one class: 29%; two classes: 27.6%; three classes: 15.8%). After adjustment, the risk of transmission relative to wild-type was reduced both for one class drug resistance (minimal and maximal estimates: odds ratio: 0.39, P<0.001; and odds ratio: 0.55, P=0.011, respectively), and for two to three class drug resistance (odds ratios: 0.05 and 0.07, respectively, P<0.001). Neither sexual behaviour nor HIV-1 RNA levels explained the low transmission of drug-resistant variants. These data suggest that drug-resistant variants and in particular multidrug-resistant variants have a substantially reduced transmission capacity.

Evaluation de la stratégie de lutte contre le cancer en Suisse, Phase 1, 1999: document de synthèse

[Table des matières] 1.1. Bref historique de la stratégie nationale de lutte contre le cancer. 1.2. Mandat d'évaluation. 1. 3. Approche d'évaluation choisie. 1.4. Phase 1 : programme d'évaluation 1999. 2. Conclusions et recommandations générales. 2.1. Stratégie et concept directeur. 2.2. Structure soutenant le programme national de lutte contre le cancer. 2.3. Rôle et fonctionnement des différents organes du programme national. 2.4. Collaborations. 2.5. Monitoring des programmes, évaluation de projets spécifiques et indicateurs à disposition pour l'évaluation globale. 3. Propositions pour la suite de l'évaluation. 4. Résumé de l'étude 1 : évaluation de la conception et de la mise en oeuvre de la stratégie au niveau national. 5. Studie 2 : Inventar der vorhandene Datenquellen und Indikatoren. 5.1. Zusammenfassung. 5.2. Allgemeine Schlussfolgerungen und Empfehlungen. 6. Studie 3 : Konzeptualisierung und Stand der Umsetzung der vier Krebsbekämpfungsprogramme. 6.1. Einleitung. 6.2. Zusammenfassung der programmübergreifende Ergebnisse : zum Konzeptualisierungsprozess, zum Steuerungsprozess, zur Vernetzung innerhalb der Programme und im relevanten Umfeld. 6.3. Zusammenfassung der programmspezifischen Ergebnisse : Brustkrebs, Hautkrebs, Lungenkrebs, Darmkrebs. 6.4. Empfehlungen : Programmübergreifende Empfehlungen, ergänzende programmspezifische Empfehlungen.

Comparison of thermogenic activity induced by the new sympathomimetic Ro 16-8714 between normal and obese subjects.

In a previous study, we demonstrated that the new beta-adrenoceptor agonist Ro 16-8714 possesses thermogenic property in normal male volunteers. The aim of the present study was to compare the metabolic response of lean vs obese individuals to a similar dose of this compound. Following an overnight fast, Ro 16-8714 (0.17 mg/kg fat free mass) or a placebo was given per os to six normal-weight subjects and to six moderately obese subjects. The rate of energy expenditure (EE) and the substrate utilization were determined by indirect calorimetry (hood system) before and for 6 h following the drug administration. Heart rate and blood pressure as well as plasma glucose, insulin and free fatty acid (FFA) concentrations were also measured at regular intervals throughout the study. The increment relative to base-line (mean +/- s.e.m.) in EE was similar in the two groups and averaged 4.0 +/- 1.4 per cent and 12.2 +/- 1.4 per cent with placebo and with Ro 16-8714 respectively in lean subjects, whereas the values reached 3.5 +/- 1.2 per cent and 14.4 +/- 2.0 per cent in obese subjects. Heart rate, systolic blood pressure, insulin and FFA were increased without any significant difference between the two groups. This study shows that Ro 16-8714 is a potent thermogenic agent both in normal and obese subjects.

Direct Effect of Birth Weight on Childhood Blood Pressure: a Causal Mediation Analysis

Background: Numerous studies have shown a negative association between birth weight (BW) and blood pressure (BP) later in life. To estimate the direct effect of BW on BP, it is conventional to condition on current weight (CW). However, such conditioning can induce collider stratification bias in the estimate of the direct effect. Objective: To bound the potential bias due to U, an unmeasured common cause of CW and BP, on the estimate of the (controlled) direct effect of BW on BP. Methods: Data from a school based study in Switzerland were used (N = 4,005; 2,010 B/1,995 G; mean age: 12.3 yr [range: 10.1-14.9]). Measured common causes of BW-BP (SES, smoking, body weight, and hypertension status of the mother) and CW-BP (breastfeeding and child's physical activity and diet) were identified with DAGs. Linear regression models were fitted to estimate the association between BW and BP. Sensitivity analyses were conducted to assess the potential effect of U on the association between BW and BP. U was assumed 1) to be a binary variable that affected BP by the same magnitude in low BWand in normal BW children and 2) to have a different prevalence in low BW children and in normal BW children for a given CW. Results: A small negative association was observed between BW and BP [beta: -0.3 mmHg/kg (95% CI: -0.9 to 0.3)]. The association was strengthened upon conditioning for CW [beta: -1.5 mmHg/kg (95% CI: -2.1 to -0.9)]. Upon further conditioning on common causes of BW-BP and CW-BP, the association did not change substantially [beta: -1.4 mmHg/kg (95% CI: -2.0 to -0.8)]. The negative association could be explained by U only if U was strongly associated with BP and if there was a large difference in the prevalence of U between low BWand normal BW children. Conclusion: The observed negative association between BW and BP upon adjustment for CW was not easily explained by an unmeasured common cause of CWand BP.