Knowledge, behaviors, and attitudes of HIV-infected men about syphilis.

OBJECTIVE: To explore knowledge on syphilis, sexual behaviors, and attitudes in men living with HIV in southwestern France. PATIENTS AND METHODS: In the ANRS CO3 Aquitaine Cohort of people living with HIV (PLHIV), a self-administered questionnaire was proposed to all male PLHIV attending one of the seven participating clinics between September 22 and October 24, 2014. The 15 questions explored patient knowledge about syphilis disease, attitudes, and behaviors during sexual intercourse. RESULTS: Among 302 patients surveyed, 101 reported at least one episode of syphilis. A history of syphilis was associated with awareness that syphilis was on the rise in men who have sex with men (MSM) in the Aquitaine region (46% vs. 22%, P<0.0001). Knowledge that syphilis could be transmitted by oral sex was low in both patients with (37%) and without (20%) a history of syphilis (P=0.0045). Patients with a history of syphilis more often used recreational drugs (RR 1.6; P=0.0028). Among 160 patients who had sexual intercourse with a man in the past 12 months, 23% reported using condoms for oral intercourse and 80% reported using condoms for anal intercourse. Sixty-two per cent of MSM declared being ready to change their practice if informed about the rise in syphilis. CONCLUSIONS: This survey revealed important information gaps in PLHIV about syphilis and related behavior. The reported receptiveness of this population to behavioral change may help inform educational interventions.

Influence of nanosecond repetitively pulsed discharges on the stability of a swirled propane/air burner representative of an aeronautical combustor.

This paper reports on an experimental study of the influence of a nanosecond repetitively pulsed spark discharge on the stability domain of a propane/air flame. This flame is produced in a lean premixed swirled combustor representative of an aeronautical combustion chamber. The lean extinction limits of the flame produced without and with plasma are determined and compared. It appears that only a low mean discharge power is necessary to increase the flame stability domain. Lastly, the effects of several parameters (pulse repetition frequency, global flowrate, electrode location) are studied.

Isometric fluctuation relations for equilibrium states with broken symmetry.

We derive a set of isometric fluctuation relations, which constrain the order parameter fluctuations in finite-size systems at equilibrium and in the presence of a broken symmetry. These relations are exact and should apply generally to many condensed-matter physics systems. Here, we establish these relations for magnetic systems and nematic liquid crystals in a symmetry-breaking external field, and we illustrate them on the Curie-Weiss and the XY models. Our relations also have implications for spontaneous symmetry breaking, which are discussed.

Energy versus information based estimations of dissipation using a pair of magnetic colloidal particles.

Using the framework of stochastic thermodynamics, we present an experimental study of a doublet of magnetic colloidal particles that is manipulated by a time-dependent magnetic field. Because of hydrodynamic interactions, each bead experiences a state-dependent friction, which we characterize using a hydrodynamic model. In this work, we compare two estimates of the dissipation in this system: the first one is energy based since it relies on the measured interaction potential, while the second one is information based since it uses only the information content of the trajectories. While the latter only offers a lower bound of the former, we find it to be simple to implement and of general applicability to more complex systems.

Non-invasive estimation of dissipation from non-equilibrium fluctuations in chemical reactions.

We show how to extract an estimate of the entropy production from a sufficiently long time series of stationary fluctuations of chemical reactions. This method, which is based on recent work on fluctuation theorems, is direct, non-invasive, does not require any knowledge about the underlying dynamics and is applicable even when only partial information is available. We apply it to simple stochastic models of chemical reactions involving a finite number of states, and for this case, we study how the estimate of dissipation is affected by the degree of coarse-graining present in the input data.

[Adherence between antibiotic prescriptions and guidelines in an internal medicine ward: an evaluation of professional practices]. / Adéquation entre les prescriptions antibiotiques et les recommandations dans un service de médecine interne : une démarche d'évaluation des pratiques professionnelles.

INTRODUCTION: This is an evaluation of professional practices (EPP) on antibiotic therapy in an internal medicine ward. MATERIAL AND METHODS: A 6-month prospective review of antibiotic prescriptions and their comparisons with local and national guidelines (drug, daily dose, administration, and duration) were performed. RESULTS: Antibiotic therapy on 227 infectious episodes was collected. According to local guidelines, we found 56% of totally respected (lower respiratory tract infections: 38%, urinary tract infections: 88% and skin infections: 73%), 33% of partially respected and 11% of non-appropriate prescriptions. Considering national guidelines for lower respiratory tract infections as references, the results were: totally respected prescriptions 81%, partially respected prescriptions 16%, and non-appropriate prescriptions 3%. CONCLUSION: This evaluation of the prescriptions allowed setting up long-lasting actions to improve clinical practice. This approach anticipates the procedures of EPP that will be needed for hospital accreditation and highlights the importance of considering several guidelines for the interpretation of the results.

Fluctuation theorem for the flashing ratchet model of molecular motors.

Molecular motors convert chemical energy derived from the hydrolysis of adenosine triphosphate (ATP) into mechanical energy. A well-studied model of a molecular motor is the flashing ratchet model. We show that this model exhibits a fluctuation relation known as the Gallavotti-Cohen symmetry. Our study highlights the fact that the symmetry is present only if the chemical and mechanical degrees of freedom are both included in the description.

Thermal expansion within a chain of magnetic colloidal particles.

We study the thermal expansion of chains formed by self-assembly of magnetic colloidal particles in a magnetic field. Using video microscopy, complete positional data of all the particles of the chains is obtained. By changing the ionic strength of the solution and the applied magnetic field, the interaction potential can be tuned. We analyze the thermal expansion of the chain using a simple model of a one-dimensional anharmonic crystal of finite size.

Stochastic model for nucleosome sliding under an external force.

Heat-induced diffusion of nucleosomes along DNA is an experimentally well-studied phenomenon, presumably induced by twist defects that propagate through the wrapped DNA portion. The diffusion constant depends dramatically on the local mechanical properties of the DNA and the presence of DNA-binding ligands. This has been quantitatively understood by a stochastic three-state model. Future experiments are expected to allow application of forces on the nucleosome that induce a directed sliding. By extending the three-state model, the present work studies theoretically the response of the nucleosome to such external forces and how it is affected by the mechanical properties of the DNA and the presence of DNA-binding ligands.

Membrane tension lowering induced by protein activity.

Using videomicroscopy we present measurements of the fluctuation spectrum of giant vesicles containing bacteriorhodopsin pumps. When the pumps are activated, we observe a significant increase of the fluctuations in the low wave vector region, which we interpret as due to a lowering of the effective tension of the membrane.

Electrostatic and electrokinetic contributions to the elastic moduli of a driven membrane.

We discuss the electrostatic contribution to the elastic moduli of a cell or artificial membrane placed in an electrolyte and driven by a DC electric field. The field drives ion currents across the membrane, through specific channels, pumps or natural pores. In steady state, charges accumulate in the Debye layers close to the membrane, modifying the membrane elastic moduli. We first study a model of a membrane of zero thickness, later generalizing this treatment to allow for a finite thickness and finite dielectric constant. Our results clarify and extend the results presented by D. Lacoste, M. Cosentino Lagomarsino, and J.F. Joanny (EPL 77, 18006 (2007)), by providing a physical explanation for a destabilizing term proportional to [see formula in text] in the fluctuation spectrum, which we relate to a nonlinear (E(2)) electrokinetic effect called induced-charge electro-osmosis (ICEO). Recent studies of ICEO have focused on electrodes and polarizable particles, where an applied bulk field is perturbed by capacitive charging of the double layer and drives the flow along the field axis toward surface protrusions; in contrast, we predict "reverse" ICEO flows around driven membranes, due to curvature-induced tangential fields within a nonequilibrium double layer, which hydrodynamically enhance protrusions. We also consider the effect of incorporating the dynamics of a spatially dependent concentration field for the ion channels.

Measuring colloidal forces with the magnetic chaining technique.

In 1994 Leal Calderon et al. (Phys. Rev. Lett. 72, 2959 (1994)) introduced the magnetic chaining technique to directly probe the force-distance profile between colloidal particles. In this paper, we revisit this approach in two ways. First, we describe a new experimental design which allows us to utilize sample volumes as low as a few microliters, involving femtomoles of surface active macromolecules. Secondly, we extensively describe the characterization and preparation of the magnetic colloids, and we give a quantitative evaluation of performance and resolution of the technique in terms of force and interparticle separation.

Fluctuation theorem and large deviation function for a solvable model of a molecular motor.

We study a discrete stochastic model of a molecular motor. This discrete model can be viewed as a minimal ratchet model. We extend our previous work on this model, by further investigating the constraints imposed by the fluctuation theorem on the operation of a molecular motor far from equilibrium. In this work, we show the connections between different formulations of the fluctuation theorem. One formulation concerns the generating function of the currents while another one concerns the corresponding large deviation function, which we have calculated exactly for this model. A third formulation concerns the ratio of the probability of observing a velocity v to the same probability of observing a velocity -v . Finally, we show that all the formulations of the fluctuation theorem can be understood from the notion of entropy production.

Nonequilibrium fluctuations and mechanochemical couplings of a molecular motor.

We investigate theoretically the violations of Einstein and Onsager relations and the thermodynamic efficiency for a single processive motor operating far from equilibrium using an extension of the two-state model introduced by Kafri et al. [Biophys. J. 86, 3373 (2004)10.1529/biophysj.103.036152]. With the aid of the Fluctuation Theorem, we analyze the general features of these violations and this efficiency and link them to mechanochemical couplings of motors. In particular, an analysis of the experimental data of kinesin using our framework leads to interesting predictions that may serve as a guide for future experiments.

[Portal vein thrombosis in HIV-infected patients: report of four cases]. / Thrombose portale chez des patients infectés par le virus de l'immunodéficience humaine: à propos de quatre observations.

Portal vein thrombosis (PVT) seems rare among HIV infected patients. Even though, the report of such cases is of great interest because it may help to determine the factors of occurrence. We describe cases of PVT in 4 HIV-infected men, aged 32 - 64. Two of them were co-infected with hepatitis C virus (HCV). The four patients had a history of disseminated mycobacterial infection (one case of tuberculosis, 3 cases of mycobacterium avium complex infection) with abdominal lymphadenitis. Despite HAART, their immunodeficiency was profound (CD4: 65 to 216/mm(3)). At the time of diagnosis, two patients were treated with protease-inhibitor containing regimen: indinavir (one case), ritonavir-saquinavir (one case). PVT was revealed by haematemesis (one case), abdominal pain (ome case), anasarca (2 cases). In three patients, the diagnosis of PVT was confirmed by imagery (echo-doppler or angio- RMI), and for the last patient, PVT was found during the transjugular intrahepatic portosystemic shunt setup. A low level of C protein was diagnosed in one case. Cirrhosis was not found in HIV-HCV co-infected patients. Two patients died early after diagnosis, one patient died 3 years after the onset of symptoms. Various factors may cause the development of a PVT in HIV infected patient. Serious immunodeficiency, opportunistic infections such as tuberculosis and mycobacterium avium complex related infection with abdominal lymphadenitis can further the development of PVT. Protease-inhibitor might have facilitated the process. Due to the severe prognosis of advanced cases, early evocation of diagnosis is needed.

[Efficacy and safety of pegylated-interferon plus ribavirin in HIV-infected patients co-infected with hepatitis C virus in clinical practice: a 32 cases observational follow-up]. / Efficacité et tolérance de l'association interféron pégylé-ribavirine chez les patients co-infectés VIH-VHC en pratique clinique: étude observationnelle de 32 patients.

OBJECTIVE: To describe efficacy and safety in clinical practice of pegylated interferon plus ribavirin (INFpeg-Riba) in the treatment of hepatitis C viral infection (HCV) in HIV infected patients. METHODS: Monocentric retrospective study with inclusion of all patients who received at least once INFpeg-Riba before April 1st 2003. All patients were followed up to six months after the end of HCV therapy. RESULTS: Thirty two HIV-positive patients (23 men and 9 women) with chronic hepatitis C treated by INFpeg-Riba were included. The mean age was 43 years. Fourteen patients carried HCV genotype 2 or 3 (43 %) and 18 patients carried genotype 1 or 4 (57%). The Metavir score of fibrosis showed fibrosis F1 (N =3), F2 (N =14), F3 (N =7) and F4 - cirrhosis (N =8). Twenty six patients (81%) were naive for anti hepatitis C drugs. Thirty one per cent of patients were at AIDS stage and 84% were receiving antiretroviral drugs. The mean CD4 cell count was 469 /ml and the plasma RNA HIV was less than 50 copies /ml in 57% of the cases. Adverse events leading to reduction of dose of drugs occurred in 40% and adverse events leading to discontinuation treatment occurred in 12%. A decline of CD4 cell count <200 CD4/ml was observed in 15%. Clearance of HCV-RNA in end of treatment was seen in 46 % and sustained virological response in 34 %. The main predictors of sustained virological response were HCV genotype 2 or 3 (P =0.04) and plasma HIV RNA less than 50 copies/ml (P =0.001). The predictive value of good virological response of a CD4 cell count >350/ml before treatment was very near the statistical significancy (p =0.07). CONCLUSIONS: The efficacy of pegylated interferon plus ribavirin in HIV-HCV co-infected patients is disappointing mainly due to a poor tolerance. In addition to HCV genotype, plasma HIV RNA level and CD4 cell count were essential to predict INFpeg-Riba response and should be taken into account in the process leading to the initiation of such therapy in HIV-HCV co-infected patients.

Symptomatic bone disorders in HIV-infected patients: incidence in the Aquitaine cohort (1999-2002).

BACKGROUND: Since the inception of highly active antiretroviral therapy (HAART), mortality among HIV-infected patients has decreased, but this has been accompanied by the appearance of several complications. OBJECTIVES: To estimate the incidence of symptomatic bone disorders in HIV-infected patients of the Aquitaine cohort (from south-west France) for the period 1999-2002, and to describe cases. METHODS: We retrospectively studied the records of 2700 patients of the Aquitaine cohort, which was derived from a hospital-based surveillance system of HIV infection in France. All cases of symptomatic bone disorders diagnosed from 1 January 1999 to 30 June 2002 were reviewed. RESULTS: Fourteen cases of bone disorders were diagnosed, eight cases of aseptic osteonecrosis and six cases of severe osteoporosis, representing incidences of 0.3/1000 patient-years [95% confidence interval (CI): 0.14-0.62] and 0.22/1000 patient-years (95% CI: 0.09-0.52), respectively. All patients with aseptic osteonecrosis were male, while all but one with osteoporosis were female. The ages of patients ranged from 36 to 54 years for osteonecrosis and from 39 to 50 for severe osteoporosis. At the time of clinical diagnosis, all patients were treated with nucleoside reverse transcriptase inhibitors (duration of treatment ranging from 19 to 123 months for osteonecrosis and from 46 to 132 months for severe osteoporosis). Ten patients were treated with nonnucleoside reverse transcriptase inhibitors [duration of treatment ranging from 6 to 31 months for osteonecrosis (n=6) and from 4 to 29 months for severe osteoporosis (n=4)]. Thirteen patients were treated with protease inhibitors [duration of treatment ranging from 12 to 62 months for osteonecrosis (n=8) and from 3 to 44 months for severe osteoporosis (n=5)]. All osteonecrosis and five osteoporosis patients had at least one known risk factor or comorbidity associated with the bone disorder occurrence. CONCLUSIONS: In our study, the aetiology of clinical bone disorders seemed to be multifactorial, as almost all the patients had at least one possible risk factor in addition to HAART exposure.

Isolated antibodies against the core antigen of hepatitis B virus in HIV-infected patients.

The aim of this study was to describe the frequency and significance of isolated antibodies against the hepatitis B virus (HBV) core antigen (HBc) in 2185 HIV-infected patients of the Aquitaine Cohort. Antibodies against HBc were found in 372 subjects (17%). Patients with isolated anti-HBc antibodies were more frequently coinfected with hepatitis C virus (HCV) (58.2%) than those who were anti-HB surface (HBs) antibody positive (22.9%, P<0.001) and those who were dually reactive anti-HBs/anti-HBc antibody positive (27.3%, P<0.001). These results suggest interactions between HBV and HCV. As observed in patients not infected with HIV, the "anti-HBc-alone" serological profile could reflect essentially late immunity with undetectable anti-HBs antibodies. However, an occult HBV infection cannot be ruled out.

Field-induced structures in miscible ferrofluid suspensions with and without latex spheres.

We explore magnetic-field-induced ordering and microphase separation of aqueous ferrofluid and of aqueous mixtures of ferrofluid with nonmagnetic latex spheres. The ferrofluid is a surfactant stabilized aqueous suspension of magnetite (Fe3O4) particles with average diameter 20 nm (including the approximately 2.5-nm thick surfactant layer); the nonmagnetic latex spheres are charge stabilized polymethylmethacrylate (PMMA) particles with diameters of 42 nm, 108 nm, and 220 nm. In the presence of a uniform magnetic field, needlelike ferrofluid droplets formed that eventually grew to sample-traversing columns at fields of approximately 600 G; the two-dimensional structure of these columns was, however, glassy rather than hexagonal. In higher fields, approximately 1000 G, the columns stretched and coalesced into sheetlike striped liquids, but a true lamellar phase was not observed. The addition of nonmagnetic latex spheres to the ferrofluid suspension lowered substantially the critical field for the formation of columns, and induced lamellar (stripe) phases at relatively low applied fields. Image analysis was used to determine the spatial correlation functions, the average needle or column spacing, and the average lamellae spacing of these samples as a function of latex sphere size and concentration.

A cohort study of nevirapine tolerance in clinical practice: French Aquitaine Cohort, 1997-1999.

We performed a retrospective study to evaluate, under routine circumstances, the tolerance and immunovirological changes associated with antiretroviral regimens that contain nevirapine in 137 patients (88% were antiretroviral experienced). During a mean follow-up of 11 months, 33% of patients reported side effects attributed to nevirapine, and 21% discontinued treatment because of poor tolerance. Administration of antihistamines or corticosteroids at the initiation of treatment was not protective against adverse events (relative risk, 0.82; 95% confidence interval, 0.49-1.38). The proportion of patients with hepatitis C virus (HCV) and/or hepatitis B virus (HBV) coinfection who had alanine aminotransferase levels of >100 IU/L increased from 19.4% at baseline to 42.9% at month 12 of follow-up (P=.02). We noticed a significant increase of the proportion of patients with total cholesterol levels of >5.5 mM (P=.02). We have shown that there is a high level of discontinuation of nevirapine therapy in clinical practice and that side effects were not prevented by administration of antihistamines or corticosteroids. Coinfection with HCV or HBV increased the risk of hepatotoxicity, which lead to the cautious use of nevirapine for such patients.