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The operation of modern free-electron lasers (FELs) necessitates precise knowledge of electron beam properties at the undulator to ensure the level of control required by increasingly demanding experiments. In seeded FELs, where only electrons interacting with the seed laser contribute to the process, it is crucial to determine the local values of these properties. We present a novel method, based on accurate modeling of the FEL process in high-gain harmonic generation, to accurately retrieve the electron beam slice energy spread, current and laser-induced energy modulation. Understanding these values is essential for enabling advanced FEL schemes and optimally setting advanced seeding schemes such as echo-enabled harmonic generation. We describe the method and provide an experimental application to the FERMI FEL-1, where a slice energy spread in the range 40-100 keV with a few keV accuracy is measured., (open access.)

Light manipulation at the nanoscale is essential both for fundamental science and modern technology. The quest to shorter lengthscales, however, requires the use of light wavelengths beyond the visible. In particular, in the extreme ultraviolet regime these manipulation capabilities are hampered by the lack of efficient optics, especially for polarization control. Here, we present a method to create periodic, polarization modulations at the nanoscale using a tailored configuration of the FERMI free electron laser and demonstrate its capabilities by comparing the dynamics induced by this polarization transient grating with those driven by a conventional intensity grating on a thin ferrimagnetic alloy. While the intensity grating signal is dominated by the thermoelastic response, the polarization grating excitation minimizes it, uncovering helicity-dependent responses previously undetected. We anticipate nanoscale polarization transient gratings to become useful for the study of physical, chemical and biological systems possessing chiral symmetry., Competing Interests: Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Tailored light-matter interactions in the strong coupling regime enable the manipulation and control of quantum systems with up to unit efficiency 1,2 , with applications ranging from quantum information to photochemistry 3-7 . Although strong light-matter interactions are readily induced at the valence electron level using long-wavelength radiation 8 , comparable phenomena have been only recently observed with short wavelengths, accessing highly excited multi-electron and inner-shell electron states 9,10 . However, the quantum control of strong-field processes at short wavelengths has not been possible, so far, because of the lack of pulse-shaping technologies in the extreme ultraviolet (XUV) and X-ray domain. Here, exploiting pulse shaping of the seeded free-electron laser (FEL) FERMI, we demonstrate the strong-field quantum control of ultrafast Rabi dynamics in helium atoms with high fidelity. Our approach reveals a strong dressing of the ionization continuum, otherwise elusive to experimental observables. The latter is exploited to achieve control of the total ionization rate, with prospective applications in many XUV and soft X-ray experiments. Leveraging recent advances in intense few-femtosecond to attosecond XUV to soft X-ray light sources, our results open an avenue to the efficient manipulation and selective control of core electron processes and electron correlation phenomena in real time., Competing Interests: Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

We demonstrate the generation of extreme-ultraviolet (XUV) free-electron laser (FEL) pulses with time-dependent polarization. To achieve polarization modulation on a femtosecond timescale, we combine two mutually delayed counterrotating circularly polarized subpulses from two cross-polarized undulators. The polarization profile of the pulses is probed by angle-resolved photoemission and above-threshold ionization of helium; the results agree with solutions of the time-dependent Schrödinger equation. The stability limit of the scheme is mainly set by electron-beam energy fluctuations, however, at a level that will not compromise experiments in the XUV. Our results demonstrate the potential to improve the resolution and element selectivity of methods based on polarization shaping and may lead to the development of new coherent control schemes for probing and manipulating core electrons in matter.

Femtosecond extreme ultraviolet wave packet interferometry (XUV-WPI) was applied to study resonant interatomic Coulombic decay (ICD) in the HeNe dimer. The high demands on phase stability and sensitivity for vibronic XUV-WPI of molecular-beam targets are met using an XUV phase-cycling scheme. The detected quantum interferences exhibit vibronic dephasing and rephasing signatures along with an ultrafast decoherence assigned to the ICD process. A Fourier analysis reveals the molecular absorption spectrum with high resolution. The demonstrated experiment shows a promising route for the real-time analysis of ultrafast ICD processes with both high temporal and high spectral resolution.

The optimal performance of high-brightness free-electron lasers (FELs) is limited by the microbunching instability, which can cause variations in both the slice energy spread and longitudinal profile of electron beams. In this paper, we perform 2D Fourier analysis of the full bunch longitudinal phase space, such that modulations in both planes can be studied simultaneously. Unlike the standard 1D analysis, this method is able to reveal modulations in a folded phase space, which would otherwise remain uncovered. Additionally, the plasma oscillation between energy and density modulations is also revealed by this method. The damping of the microbunching instability, through the use of a laser heater, is also analysed with this technique. We confirm a mitigation of the amplitude of modulation and a red-shift of the microbunching frequency as the energy spread added increases. As an outcome of this work, a systematic experimental comparison of the development of the instability in the presence of different compression schemes is here presented for the first time.

The recent development of ultrafast extreme ultraviolet (XUV) coherent light sources bears great potential for a better understanding of the structure and dynamics of matter. Promising routes are advanced coherent control and nonlinear spectroscopy schemes in the XUV energy range, yielding unprecedented spatial and temporal resolution. However, their implementation has been hampered by the experimental challenge of generating XUV pulse sequences with precisely controlled timing and phase properties. In particular, direct control and manipulation of the phase of individual pulses within an XUV pulse sequence opens exciting possibilities for coherent control and multidimensional spectroscopy, but has not been accomplished. Here, we overcome these constraints in a highly time-stabilized and phase-modulated XUV-pump, XUV-probe experiment, which directly probes the evolution and dephasing of an inner subshell electronic coherence. This approach, avoiding any XUV optics for direct pulse manipulation, opens up extensive applications of advanced nonlinear optics and spectroscopy at XUV wavelengths.

Attosecond pulses are central to the investigation of valence- and core-electron dynamics on their natural timescales 1-3 . The reproducible generation and characterization of attosecond waveforms has been demonstrated so far only through the process of high-order harmonic generation 4-7 . Several methods for shaping attosecond waveforms have been proposed, including the use of metallic filters 8,9 , multilayer mirrors 10 and manipulation of the driving field 11 . However, none of these approaches allows the flexible manipulation of the temporal characteristics of the attosecond waveforms, and they suffer from the low conversion efficiency of the high-order harmonic generation process. Free-electron lasers, by contrast, deliver femtosecond, extreme-ultraviolet and X-ray pulses with energies ranging from tens of microjoules to a few millijoules 12,13 . Recent experiments have shown that they can generate subfemtosecond spikes, but with temporal characteristics that change shot-to-shot 14-16 . Here we report reproducible generation of high-energy (microjoule level) attosecond waveforms using a seeded free-electron laser 17 . We demonstrate amplitude and phase manipulation of the harmonic components of an attosecond pulse train in combination with an approach for its temporal reconstruction. The results presented here open the way to performing attosecond time-resolved experiments with free-electron lasers.

Intense, mutually coherent beams of multiharmonic extreme ultraviolet light can now be created using seeded free-electron lasers, and the phase difference between harmonics can be tuned with attosecond accuracy. However, the absolute value of the phase is generally not determined. We present a method for determining precisely the absolute phase relationship of a fundamental wavelength and its second harmonic, as well as the amplitude ratio. Only a few easily calculated theoretical parameters are required in addition to the experimental data.

Objectives: The aim of the study was to analyse the prevalence of integrase resistance mutations in integrase strand transfer inhibitor (INSTI)-experienced HIV-1-infected patients and its predictors., Methods: We selected HIV-1 integrase sequences from the Antiviral Response Cohort Analysis (ARCA) database, derived from INSTI-experienced patients between 2008 and 2017. Differences in the prevalence of resistance to raltegravir (RAL), elvitegravir (EVG) and dolutegravir (DTG) were assessed by χ 2 test and predictors of resistance were analysed by logistic regression., Results: We included 462 genotypes from INSTI-exposed individuals: 356 'INSTI-failing' patients and 106 'previously INSTI-exposed' patients (obtained a median of 42 weeks after INSTI discontinuation [interquartile range (IQR) 17-110 weeks]). Overall, at least low-level resistance (LLR) to any INSTI (Stanford 8.5 algorithm) was detected in 198 (42.9%) cases. The most frequent INSTI resistance mutation was N155H, followed by Q148H/K/R, G140A/C/S, E138A/K/T and Y143C/H/R. Y143R and E138A were more prevalent in viral subtype B versus non-B [5.2 versus 1.5%, respectively (P = 0.04), and 3.1 versus 0%, respectively (P = 0.02)]. Overall, the Q148H/K/R plus G140A/C/S and/or E138A/K/T pattern, defining an intermediate level of resistance to DTG, was detected in 70 (15%) cases. Independent predictors of at least LLR to any INSTI were current use versus past use of INSTIs, a lower genotypic sensitivity score (GSS) for contemporary antiretroviral drugs used, and having an integrase sequence obtained in calendar year 2016 as compared to 2008-2009., Conclusions: The results support integrase resistance testing in INSTI-experienced patients. Emergence of INSTI resistance is facilitated by the reduced genetic barrier of the regimen as a consequence of resistance to companion drugs. However, INSTI resistance may become undetectable by standard population sequencing upon INSTI discontinuation., (© 2018 British HIV Association.)

Objectives: To examine the impact of transmitted drug resistance (TDR) on response to first-line regimens with integrase strand transfer inhibitors (INSTIs) or boosted protease inhibitors (bPIs)., Methods: From an Italian observational database (ARCA) we selected HIV-1-infected drug-naive patients starting two NRTIs and either an INSTI or a bPI, with an available pre-ART resistance genotype. The endpoint was virological failure (VF; plasma HIV-1 RNA >200 copies/mL after week 24). WHO surveillance drug resistance mutations and the Stanford algorithm were used to classify patients into three resistance categories: no TDR (A), TDR but fully-active ART prescribed (B), TDR and at least low-level resistance to one or more prescribed drug (C)., Results: We included 1365 patients with a median follow-up of 96 weeks (IQR 54-110): 1205 (88.3%) starting bPI and 160 (11.7%) INSTI. Prevalence of TDR was 6.1%, 12.5%, 2.6% and 0% for NRTI, NNRTI, bPI and INSTI, respectively. Cumulative Kaplan-Meier estimates for VF at 48 weeks were 11% (95% CI 10.1%-11.9%) for the bPI group and 7.7% (95% CI 5.4%-10%) for the INSTI group. In the INSTI group, cumulative estimates for VF at 48 weeks were 6% (95% CI 4%-8%) in resistance category A, 5% (95% CI 1%-10%) in B and 50% (95% CI 30%-70%) in C (P < 0.001). Resistance category C [versus A, adjusted hazard ratio (aHR) 12.6, 95% CI 3.2-49.8, P < 0.001] and nadir CD4 (+100 cells/mm3, aHR 0.6, 95% CI 0.4-0.9, P = 0.03) predicted VF. In the bPI group, VF rates were not influenced by baseline resistance., Conclusions: Our data support the need for NRTI resistance genotyping in patients starting an INSTI-based first-line ART.

We demonstrate that emission of coherent transition radiation by a ∼1 GeV energy-electron beam passing through an Al foil is enhanced in intensity and extended in frequency spectral range, by the energy correlation established along the beam by coherent synchrotron radiation wakefield, in the presence of a proper electron optics in the beam delivery system. Analytical and numerical models, based on experimental electron beam parameters collected at the FERMI free electron laser (FEL), predict transition radiation with two intensity peaks at ∼0.3 THz and ∼1.5 THz, and extending up to 8.5 THz with intensity above 20 dB w.r.t. the main peak. Up to 80-µJ pulse energy integrated over the full bandwidth is expected at the source, and in agreement with experimental pulse energy measurements. By virtue of its implementation in an FEL beam dump line, this work promises dissemination of user-oriented multi-THz beamlines parasitic and self-synchronized to EUV and x-ray FELs.

Rilpivirine is associated with a good efficacy and safety profile. However, data from real-life settings are scarce., Methods: We investigated the durability, safety and efficacy of Rilpivirine-based antiretroviral therapy in a prospective, observational, multicenter study., Results: We enrolled 499 HIV-infected patients, 360 (72.1%) males, mean age 43.4 ± 10.5 years, mean CD4 600 ± 327 cell/μL, mean HIV-RNA 3.80 ± 1.15 log 10 cp/mL. After a median follow up of 16 months, 81 (16.2%) interruptions were reported, 36 (7.2%) of which for adverse events (16 of grade ≥3), most commonly neurological and gastrointestinal. We observed virological failures in only 8 (1.6%) patients. Naive patients showed a significant reduction in eGFR at week 24, 48 and 72 and in total cholesterol (TC)/HDL ratio at week 48 ( p =0.007). In patients switching from PI we found a significant decrease at week 24 and 48 in TC and triglycerides at week 24, 48 and 72. eGFR showed a significant decrease at week 48 and 72. TC/HDL ratio showed a statistically significant decrease at week 24 ( p =0.0008) and 72 ( p =0.04). A significant increase at week 24 and 48 in AST and ALT values was observed. Patients switching from TDF/FTC/EFV showed a reduction in HDL, total cholesterol and triglycerides at week 24 and 48 and in eGFR at all follow up times. TC/HDL ratio showed a significant decrease at week 48 ( p =0.01). CDC stage C and antiretroviral-experience (especially Protease Inhibitors) were associated with RPV discontinuation., Conclusion: In conclusion, our data confirm Rilpivirine efficacy, safety and tolerability with improvement in lipid profile. Although hepatic and renal events rarely caused discontinuation, liver and kidney parameters should be monitored., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Nonlinear optical processes at soft x-ray wavelengths have remained largely unexplored due to the lack of available light sources with the requisite intensity and coherence. Here we report the observation of soft x-ray second harmonic generation near the carbon K edge (∼284  eV) in graphite thin films generated by high intensity, coherent soft x-ray pulses at the FERMI free electron laser. Our experimental results and accompanying first-principles theoretical analysis highlight the effect of resonant enhancement above the carbon K edge and show the technique to be interfacially sensitive in a centrosymmetric sample with second harmonic intensity arising primarily from the first atomic layer at the open surface. This technique and the associated theoretical framework demonstrate the ability to selectively probe interfaces, including those that are buried, with elemental specificity, providing a new tool for a range of scientific problems.

In linac-driven free-electron lasers, colliders, and energy recovery linacs, a common way to compress the electron bunch to kiloampere level is based upon the implementation of a magnetic dispersive element that converts particle energy deviation into a path-length difference. Nonlinearities of such a process are usually compensated by enabling a high harmonic rf structure properly tuned in amplitude and phase. This approach is however not straightforward, e.g., in C-band and X-band linacs. In this Letter we demonstrate that the longitudinal self-induced field excited by the electron beam itself is able to linearize the compression process without any use of high harmonic rf structure. The method is implemented at the FERMI linac, with the resulting high quality beam used to drive the seeded free-electron laser during user experiments.

The hitherto unexplored two-photon doubly excited states [Ne^{*}(2p^{-1}3s)]&#95;{2} were experimentally identified using the seeded, fully coherent, intense extreme ultraviolet free-electron laser FERMI. These states undergo ultrafast interatomic Coulombic decay (ICD), which predominantly produces singly ionized dimers. In order to obtain the rate of ICD, the resulting yield of Ne&#95;{2}^{+} ions was recorded as a function of delay between the extreme ultraviolet pump and UV probe laser pulses. The extracted lifetimes of the long-lived doubly excited states, 390(-130/+450)  fs, and of the short-lived ones, less than 150 fs, are in good agreement with ab initio quantum mechanical calculations.

Ne clusters (∼5000  atoms) were resonantly excited (2p→3s) by intense free electron laser (FEL) radiation at FERMI. Such multiply excited clusters can decay nonradiatively via energy exchange between at least two neighboring excited atoms. Benefiting from the precise tunability and narrow bandwidth of seeded FEL radiation, specific sites of the Ne clusters were probed. We found that the relaxation of cluster surface atoms proceeds via a sequence of interatomic or intermolecular Coulombic decay (ICD) processes while ICD of bulk atoms is additionally affected by the surrounding excited medium via inelastic electron scattering. For both cases, cluster excitations relax to atomic states prior to ICD, showing that this kind of ICD is rather slow (picosecond range). Controlling the average number of excitations per cluster via the FEL intensity allows a coarse tuning of the ICD rate.

Chirped pulse amplification in optical lasers is a revolutionary technique, which allows the generation of extremely powerful femtosecond pulses in the infrared and visible spectral ranges. Such pulses are nowadays an indispensable tool for a myriad of applications, both in fundamental and applied research. In recent years, a strong need emerged for light sources producing ultra-short and intense laser-like X-ray pulses, to be used for experiments in a variety of disciplines, ranging from physics and chemistry to biology and material sciences. This demand was satisfied by the advent of short-wavelength free-electron lasers. However, for any given free-electron laser setup, a limit presently exists in the generation of ultra-short pulses carrying substantial energy. Here we present the experimental implementation of chirped pulse amplification on a seeded free-electron laser in the extreme-ultraviolet, paving the way to the generation of fully coherent sub-femtosecond gigawatt pulses in the water window (2.3-4.4 nm).

Background: PrEP with FTC/TDF has shown great efficacy in preventing new HIV infections but issues remain (low adherence, high costs, toxicity and resistance development). No data are available about the impact of circulating Resistance-Associated Mutations (RAMs) on its efficacy., Objectives: describe the prevalence of FTC and/or TDF-related RAMs in Italian HIV-infected population and their potential impact on PrEP efficacy., Study Design: ARCA is a national database that collects data about RAMs and epidemiological correlates from sites throughout Italy; it was queried about the prevalence of these RAMs in the last decade. PrEP efficacy was adjusted for a dynamic score based on RAMs prevalence. Absolute and relative risk increases (ARI and RRI) and number needed to harm (NNH) were calculated after this score., Results: the query retrieved 3579 HAART-naïve and 5781 experienced subjects. Resistance to TDF is low and more common among naïve MSM in the area of Milan (where it topped to 14.3%), without other significant differences. If good adherence is not attained, RRI for receptive anal sex increases by 16% (in naïve) and 93.4% (in experienced MSM). NNH is largely above 10000 except for having receptive anal sex with a HAART-experienced MSM on a failing treatment (970)., Conclusions: according to this model, PrEP may be introduced in Italy without general concerns, but efficacy may be partly reduced in young MSM having sex in Rome and Milan., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Objectives: To investigate the use of statins and acetylsalicylic acid (ASA) in HIV people in clinical practice., Design: A multicenter, nationwide, prospective cohort study, including 1182 consecutive HIV patients was conducted., Methods: Statin and ASA prescription was evaluated in primary and secondary cardiovascular disease prevention, according to the European AIDS Clinical Society (EACS) guidelines., Results: Followed-up patients (998) were mostly males (70.9 %) with a mean age at enrolment of 46.5 years (SD 9.5). The mean time of follow-up was 3.3 years (SD 0.8). At the last follow-up visit, statins would have been recommended for 31.2 % and ASA for 16 % by EACS guidelines. Conversely, only 15.6 and 7.6 % of patients were on statin and ASA treatment, respectively; only 50.3 % of patients treated with statins achieved recommended low-density lipoprotein cholesterol (LDL-c) levels. At the last follow-up visit, agreement between statin therapy and EACS recommendation was 0.58 (95 % CI 0.52-0.63). The corresponding figure for ASA therapy was 0.50 (95 % CI 0.42-0.58), whereas the agreement for ASA therapy in secondary prevention was 0.59 (95 % CI 0.50-0.68)., Conclusions: The prescription of statins and ASA in HIV-infected patients remains largely suboptimal, as only about 50 % of patients requiring statins and ASA are properly treated. Higher attention on this relevant issue and further investigation are warranted in this at risk population.

The advent of free-electron laser (FEL) sources delivering two synchronized pulses of different wavelengths (or colours) has made available a whole range of novel pump-probe experiments. This communication describes a major step forward using a new configuration of the FERMI FEL-seeded source to deliver two pulses with different wavelengths, each tunable independently over a broad spectral range with adjustable time delay. The FEL scheme makes use of two seed laser beams of different wavelengths and of a split radiator section to generate two extreme ultraviolet pulses from distinct portions of the same electron bunch. The tunability range of this new two-colour source meets the requirements of double-resonant FEL pump/FEL probe time-resolved studies. We demonstrate its performance in a proof-of-principle magnetic scattering experiment in Fe-Ni compounds, by tuning the FEL wavelengths to the Fe and Ni 3p resonances.

Laser-heater systems are essential tools to control and optimize high-gain free-electron lasers (FELs) working in the x-ray wavelength range. Indeed, these systems induce a controllable increase of the energy spread of the electron bunch. The heating suppresses longitudinal microbunching instability which otherwise would limit the FEL performance. Here, we demonstrate that, through the action of the microbunching instability, a long-wavelength modulation of the electron beam induced by the laser heater at low energy can persist until the beam entrance into the undulators. This coherent longitudinal modulation is exploited to control the FEL spectral properties, in particular, multicolor extreme-ultraviolet FEL pulses can be generated through a frequency mixing of the modulations produced by the laser heater and the seed laser in the electron beam. We present an experimental demonstration of this novel configuration carried out at the FERMI FEL.

We demonstrate the ability to control and shape the spectrotemporal content of extreme-ultraviolet (XUV) pulses produced by a seeded free-electron laser (FEL). The control over the spectrotemporal properties of XUV light was achieved by precisely manipulating the linear frequency chirp of the seed laser. Our results agree with existing theory, which allows us to retrieve the temporal properties (amplitude and phase) of the FEL pulse from measurements of the spectra as a function of the FEL operating parameters. Furthermore, we show the first direct evidence of the full temporal coherence of FEL light and generate Fourier limited pulses by fine-tuning the FEL temporal phase. The possibility of tailoring the spectrotemporal content of intense short-wavelength pulses represents the first step towards efficient nonlinear optics in the XUV to x-ray spectral region and will enable precise manipulation of core-electron excitations using the methods of coherent quantum control.

Polarization control is a key feature of light generated by short-wavelength free-electron lasers. In this work, we report the first experimental characterization of the polarization properties of an extreme ultraviolet high gain free-electron laser operated with crossed polarized undulators. We investigate the average degree of polarization and the shot-to-shot stability and we analyze aspects such as existing possibilities for controlling and switching the polarization state of the emitted light. The results are in agreement with predictions based on Gaussian beams propagation.

Intense ultrashort X-ray pulses produced by modern free-electron lasers (FELs) allow one to probe biological systems, inorganic materials and molecular reaction dynamics with nanoscale spatial and femtoscale temporal resolution. These experiments require the knowledge, and possibly the control, of the spectro-temporal content of individual pulses. FELs relying on seeding have the potential to produce spatially and temporally fully coherent pulses. Here we propose and implement an interferometric method, which allows us to carry out the first complete single-shot spectro-temporal characterization of the pulses, generated by an FEL in the extreme ultraviolet spectral range. Moreover, we provide the first direct evidence of the temporal coherence of a seeded FEL working in the extreme ultraviolet spectral range and show the way to control the light generation process to produce Fourier-limited pulses. Experiments are carried out at the FERMI FEL in Trieste.

Background: We assessed the virological response of dual therapy with DRV/r, plus raltegravir, maraviroc or etravirine, in virological failure patients and in virologically suppressed patients collected in the Italian Antiretroviral Resistance Database (ARCA)., Material and Methods: The primary endpoint was the percentage of patients remaining free of virological failure (confirmed >50 copies/mL or any change in the regimen). Subjects had a resistance test and at least one follow-up visit. Observation was censored at last visit under dual therapy and survival analysis and proportional hazard models were used., Results: Sixty-seven percent of the 221 patients started DRV/r with RAL, 20.4 % with ETV, and 12.2 % with MAR; 31.2 % virological failures were observed. At survival analysis, the overall proportion of failure was 29.2 % at 1 year and 33.8 % at 2 years. The proportion of failure was lower in patients starting with undetectable vs. detectable viral load (13.3 and 25.2 % vs. 37.4 and 38.8 % at 1 and 2 years, respectively, p = 0.001 for both analyses) and in patients treated with DRV 600 BID vs. 800 QD (HR: 0.56, 95 % CI: 0.31-0.99, p < 0.05). By regimen, the adjusted proportional model showed no significant difference among the three regimens. A significant lower risk of failure was associated with higher GSS (HIV-DB HR: 0.53, 95 % CI: 0.32-0.88, p = 0.014; Rega 0.60, 0.40-0.88, p < 0.01; ANRS 0.55, 0.34-0.90, p = 0.017), while a higher risk of failure with detectable HIV-RNA (3.02, 1.70-5.72, p < 0.001)., Conclusions: Among experienced patients, the best candidates for dual-therapy regimens including DRV/r are those with undetectable viral load and higher GSS.

FERMI is a seeded free-electron laser (FEL) facility located at the Elettra laboratory in Trieste, Italy, and is now in user operation with its first FEL line, FEL-1, covering the wavelength range between 100 and 20 nm. The second FEL line, FEL-2, a high-gain harmonic generation double-stage cascade covering the wavelength range 20-4 nm, has also completed commissioning and the first user call has been recently opened. An overview of the typical operating modes of the facility is presented.

Muscle alterations ranging from asymptomatic creatine phosphokinase (CPK) increases to rhabdomyolysis and central nervous system (CNS) symptoms have been reported in patients receiving raltegravir. Muscle symptoms and CPK increases were investigated in a cohort of HIV-infected patients receiving raltegravir-based antiretroviral therapy, and possible associated predictors were evaluated. The SCOLTA Project is a prospective, observational, multicentre study created to assess the incidence of adverse events in patients receiving new antiretroviral drugs in clinical practice. In total, 496 HIV-infected patients were enrolled [333 (67.1%) male]. CDC stage was C in 196 patients (39.5%). Mean age at enrolment was 45.9 ± 9.3 years. Median follow-up was 21 months. Twenty-six patients (5.2%) reported muscle symptoms (16 muscle pain and 17 weakness; 7 had both). Of 342 patients with normal baseline CPK values, 72 (21.1%) had a CPK increase. Seven patients (1.4%) discontinued raltegravir because of muscular events (three for muscle pain/weakness and four CPK increases). No cases of rhabdomyolysis were observed. Patients with muscle symptoms were more frequently receiving in their regimen than those not receiving atazanavir (P=0.04) and were more likely to also report CNS symptoms (P<0.0001). Significant predictors of muscle symptoms were CNS symptoms and use of atazanavir. Female sex was associated with a reduced risk of CPK increase. In conclusion, muscle symptoms and CPK elevations occurred frequently and caused most discontinuations due to adverse events. Their monitoring in patients receiving raltegravir should be considered, especially when co-administered with atazanavir or when CNS symptoms are also present., (Copyright © 2014 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.)

The relationship between hepatic tolerance and hepatitis C virus (HCV) co-infection has not been extensively studied in clinical practice. We assessed the efficacy and safety of raltegravir-based therapy in an Italian cohort of HIV/HCV co-infected patients. One hundred and forty patients with HIV/HCV co-infection initiating raltegravir from SCOLTA project (Surveillance Cohort Long-Term Toxicity Antiretrovirals) were examined. Of them, 43 were women, with mean age of 45.4±6.4years; 65 (46%) had undetectable HIV-RNA<50copies/mL and 75 (54%) HIV-RNA≥50copies/mL. According to CDC classification, 49 (35%) were in stage C. Based on Fib4 score at the time of starting raltegravir, patients were classified in class I in 41 cases, class II in 68 and in class III in 31 cases. Globally, the Fib4 score slightly decreased during 24months follow-up, from 2.2 to a value of 1.8. Hepatic adverse events of any grade were observed in 67 patients, of which only 2 cases (3%) had severe liver toxicity (grade 3-4). Only one patient had to discontinue the therapy because of adverse events. According to univariate analysis, being in CDC stage C represented a risk for the development of liver toxicity, with a hazard ratio (HR) of 2.27 (95% CI 1.06-4.84, P=0.033). None of the other variables considered (age, sex, years since detection of HIV and HCV-RNA detectable, years of previous HIV therapy, concomitant therapy with PI or NRTI, CD4+ cell count, Fib4, and transaminases level at baseline) resulted statistically correlated to the outcome. In conclusion, raltegravir-based regimens can be safely used in HCV infected patients; in this study, the hepatic toxicity has been found to be more frequent in patients with an advanced HIV disease (CDC stage C), independently of HIV-RNA suppression at raltegravir initiation., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

We report the first experimental evidence of enhancement of self-amplified spontaneous emission, due to the use of an optical klystron. In this free-electron laser scheme, a relativistic electron beam passes through two undulators, separated by a dispersive section. The latter converts the electron-beam energy modulation produced in the first undulator in density modulation, thus enhancing the free-electron laser gain. The experiment has been carried out at the FERMI facility in Trieste. Powerful radiation has been produced in the extreme ultraviolet range, with an intensity a few orders of magnitude larger than in pure self-amplified spontaneous emission mode. Data have been benchmarked with an existing theoretical model.

Background: We assessed the virological response of DRV/r-based dual therapy in drug-experienced patients included in the Italian antiretroviral resistance database (ARCA)., Materials and Methods: Patients included in the study were treated with DRV/r in association with raltegravir (RAL), etravirine (ETV) or maraviroc (MAR) following treatment failure(s) and with a resistance test and at least one follow-up visit available. Observation was censored at last visit under dual therapy and survival analysis and proportional hazard models were used, taking virological failure (confirmed >50 c/mL HIV-RNA) as the end-point., Results: Of the total 221 patients included, 149 (67.4%) started DRV/r with RAL, 45 (20.4%) with ETV, 27 (12.2%) with MAR. Patients characteristics at the start of dual regimen were as follows: mean number of previous regimens, nine (IQR: 5-13); non-B subtype, 17 (7.7%); median CD4 count, 347 (IQR: 246-544); undetectable viral load, 74 (33.5%). Full DRV/r resistance was detected in one (0.5%, HIV-DB interpretation system), 13 (5.9%, ANRS) and 17 patients (7.7%, Rega). 69 virological failures (31.2%) were observed during follow-up. At survival analysis, the overall proportion of failure was 29.2% at one year and 33.8% at two years. The proportion of failure was lower in patients starting with undetectable versus detectable viral load (13.3% and 25.2% versus 37.4% and 38.8% at one and two years, respectively, p=0.001 for both analyses) and in patients treated with DRV 600 BID versus 800 QD (HR: 0, 56; 95% CI 0.31-0.99; p<0.05). By regimen, patients treated with DRV/r-RAL showed a non-significant lower proportion of failure (27.7% at one year, 32.0% at two years) if compared with DRV/r-MAR (35.9%, 47.1%) and DRV/r-ETV (34.1%, 34.1% at one and two years). In the adjusted proportional model, no significant difference among the three regimens was detected. A significant lower risk of failure was associated with higher overall GSS (HIV-DB HR: 0.53, 95% CI 0.32-0.88, p=0.014; Rega 0.60, 0.40-0.88, p<0.01; ANRS 0.55, 0.34-0.90, p=0.017), while a higher risk of failure was associated with detectable HIV-RNA (3.02, 1.70-5.72, p<0.001)., Conclusions: Among experienced patients, the best candidates to dual-therapy regimens including DRV/r are those with undetectable viral load and higher GSS. The association with RAL is the most commonly used but no clear advantage with respect to ETV or MAR was observed in our dataset, possibly due to the limited sample size.

The factors influencing virological response to first-line combined antiretroviral therapy (cART) in an Italian cohort of HIV-1-infected patients were examined. Eligible patients were those enrolled in a national prospective observational cohort (Antiretroviral Resistance Cohort Analysis), starting first-line cART between 2001 and 2011 and who had at least one follow-up of HIV-1 RNA. The primary endpoint was virological success, defined as the first viral load <50  copies/ml. Time to events were analyzed by Kaplan-Meier analysis and Cox proportional hazard model. One thousand three hundred five patients met the study inclusion criteria. In a multivariable model adjusting for transmission mode, presence of transmitted drug resistance, baseline CD4(+) cell count, viral subtype, and type of NRTI backbone employed, independent predictors of virological success were higher baseline viral load (≥500,000 vs. <100,000 HR 0.52; P < 0.001), a weighted genotypic susceptibility score (wGSS) <3 (HR 0.58; P = 0.003), male sex (HR 0.76 P = 0.001), and type of initial third drug employed (integrase inhibitor vs. boosted protease inhibitors HR 3.23; P < 0.001). In the subset with HIV-1 RNA >100,000  copies/ml, virologic success was only associated with the use of integrase inhibitors in the first cART regimen. Independent predictors of immunological success were baseline CD4(+) cell count and wGSS <3. High baseline HIV-1 RNA, predicted activity of the first-line regimen based on genotypic resistance testing, gender, and use of new agents were found to predict time to achieve virological success. The type of initial nucleoside analog backbone was not found to predict virological response., (© 2014 Wiley Periodicals, Inc.)

Background: The pilot phase IIb VIKING study suggested that dolutegravir (DTG), a human immunodeficiency virus (HIV) integrase inhibitor (INI), would be efficacious in INI-resistant patients at the 50 mg twice daily (BID) dose., Methods: VIKING-3 is a single-arm, open-label phase III study in which therapy-experienced adults with INI-resistant virus received DTG 50 mg BID while continuing their failing regimen (without raltegravir or elvitegravir) through day 7, after which the regimen was optimized with ≥1 fully active drug and DTG continued. The primary efficacy endpoints were the mean change from baseline in plasma HIV-1 RNA at day 8 and the proportion of subjects with HIV-1 RNA <50 c/mL at week 24., Results: Mean change in HIV-1 RNA at day 8 was -1.43 log10 c/mL, and 69% of subjects achieved <50 c/mL at week 24. Multivariate analyses demonstrated a strong association between baseline DTG susceptibility and response. Response was most reduced in subjects with Q148 + ≥2 resistance-associated mutations. DTG 50 mg BID had a low (3%) discontinuation rate due to adverse events, similar to INI-naive subjects receiving DTG 50 mg once daily., Conclusions: DTG 50 mg BID-based therapy was effective in this highly treatment-experienced population with INI-resistant virus., Clinical Trials Registration: www.clinicaltrials.gov (NCT01328041) and http://www.gsk-clinicalstudywww.gsk-clinicalstudyregister.com (112574)., (© The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.)

Objectives: Evaluate gender differences with regard to baseline characteristics and outcome of therapy in cohorts of the SCOLTA (surveillance cohort long-term toxicity of antiretrovirals) project., Methods: The SCOLTA project is an active pharmacovigilance system for new antiretroviral drugs. Since 2002, patients were enrolled in nine cohorts (lopinavir, tenofovir, atazanavir, fosamprenavir, enfuvirtide, tipranavir, darunavir, raltegravir and maraviroc)., Results: Two thousand one hundred and fifty-four patients were included in 5 PI cohorts; 607 (28.2%) were female. Women were younger and less frequently HCV-coinfected than men. At study entry, they were less frequently in CDC stage C, but CD4+ cells/mm(3) and detectable HIV-RNA were not different by gender. Women had triglycerides alterations less frequently than men, but showed a higher proportion of low HDL-cholesterol. Women were protected from incident grade 2-4 triglycerides increase (odds ratio=0.39, 95% confidence interval 0.18-0.88; P=0.02). Mean CD4+ cell count increased in both men and women; despite a non-significantly lower initial CD4+ level, women had a better immunological recovery. Women discontinued PI treatment for adverse events and their own will more frequently., Conclusions: In these cohorts, gender distribution mirrored the Italian HIV population. Women were younger than men when they started their first ARV therapy and when they entered our cohorts. On the same treatment, they had a better immune response, though no significant difference emerged on virologic control and treatment durability. As compared to men, women appeared at lower risk of hypertriglyceridaemia. They stopped PI-based treatment of their own will more frequently than men, suggesting the need for a focused effort on adherence., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Laser-heater systems have been demonstrated to be an important component for the accelerators that drive high gain free electron laser (FEL) facilities. These heater systems suppress longitudinal microbunching instabilities by inducing a small and controllable slice energy spread to the electron beam. For transversely uniform heating, the energy spread augmentation is characterized by a non-Gaussian distribution. In this Letter, we demonstrate experimentally that in addition to suppression of the microbunching instability, the laser heater-induced energy distribution can be preserved to the FEL undulator entrance, significantly impacting the performance of high-gain harmonic generation (HGHG) FELs, especially at soft x-ray wavelengths. In particular, we show that the FEL intensity has several local maxima as a function of the induced heating caused by the non-Gaussian energy distribution together with a strong enhancement of the power at high harmonics relative to that expected for an electron beam with an equivalent Gaussian energy spread at an undulator entrance. These results suggest that a single stage HGHG FEL can produce scientifically interesting power levels at harmonic numbers m ≥ 25 and with current seed laser technology could reach output photon energies above 100 eV or greater.

Cardiovascular risk profile was compared in 765 Italian HIV-infected outpatients enrolled in 2005 and in 765 individually age-matched and sex-matched patients enrolled in 2011. Median Framingham risk score was 8.6% in 2005 vs. 7.9% in 2011 (P = 0.04); metabolic syndrome was present in 40.3% vs. 33.4% (P = 0.006). Blood glucose, triglycerides, prevalence of smokers, and lipodystrophy were all significantly lower in 2011 (all P < 0.0001). Cardiovascular risk improved over a 6-year period in Italian HIV-infected patients.

Control of the electron-beam longitudinal-phase-space distribution is of crucial importance in a number of accelerator applications, such as linac-driven free-electron lasers, colliders and energy recovery linacs. Some longitudinal-phase-space features produced by nonlinear electron beam self- fields, such as a quadratic energy chirp introduced by geometric longitudinal wakefields in radio-frequency (rf) accelerator structures, cannot be compensated by ordinary tuning of the linac rf phases nor corrected by a single high harmonic accelerating cavity. In this Letter we report an experimental demonstration of the removal of the quadratic energy chirp by properly shaping the electron beam current at the photoinjector. Specifically, a longitudinal ramp in the current distribution at the cathode linearizes the longitudinal wakefields in the downstream linac, resulting in a flat electron current and energy distribution. We present longitudinal-phase-space measurements in this novel configuration compared to those typically obtained without longitudinal current shaping at the FERMI linac.

The front-end injection systems of the FERMI@Elettra linac produce high brightness electron beams that define the performance of the Free Electron Laser. The photoinjector mainly consists of the radiofrequency (rf) gun and of two S-band rf structures which accelerate the beam. Accelerating structures endowed with a single feed coupler cause deflection and degradation of the electron beam properties, due to the asymmetry of the electromagnetic field. In this paper, a new type of single feed structure with movable short-circuit is proposed. It has the advantage of having only one waveguide input, but we propose a novel design where the dipolar component is reduced. Moreover, the racetrack geometry allows to reduce the quadrupolar component. This paper presents the microwave design and the analysis of the particle motion inside the linac. A prototype has been machined at the Elettra facility to verify the new coupler design and the rf field has been measured by adopting the bead-pull method. The results are here presented, showing good agreement with the expectations.

Raltegravir (RAL) is the only licensed human immunodeficiency virus (HIV) integrase inhibitor. The factors associated with the virological response to RAL-containing regimens and the prevalence of integrase mutations associated with RAL failure deserve further investigation. From the Antiretroviral Resistance Cohort Analysis database, we selected triple-class-experienced subjects failing their current treatment with complete treatment history available. Selection criteria included HIV-RNA, CD4 count and HIV genotype within 3 months of RAL initiation. Factors associated with 24-week response were analysed; genotypic sensitivity scores (GSS) and weighted-GSS were evaluated. Virological response was achieved in 74.3% of 105 subjects. Mutations associated with RAL failure were detected in 12/24 subjects with an integrase genotype, with the prevalence of Q148H + G140S. Each extra unit of GSS (p 0.05, OR 2.62; 95% CI 1.00-6.87). was found to be a associated with response. Weighted-GSS had borderline statistical significance (p 0.063, OR 2.04; 95% CI 0.96-4.33) When stratifying for different cut-offs (<1 as reference, 1-1.49, ≥1.5), a borderline significant increase in the probability of response appeared for GSS ≥1.5 (p 0.053, OR 4.00; 95% CI 0.98-16.25). GSS ≥1 showed the highest sensitivity, 82.6%. Receiver operating characteristic curves depicted the widest area under the curve (0.663, p 0.054) of GSS ≥1. Unresponsiveness to RAL-containing regimens among triple-class-experienced subjects was low. The activity of the background regimen was strongly associated with response. Although few integrase genotypes were available at failure, half of these were without integrase resistance mutations. The substantial rate of RAL failure in the absence of known RAL-resistance mutations may be associated with adherence issues and this issue warrants further analysis in longer observations., (© 2013 The Authors Clinical Microbiology and Infection © 2013 European Society of Clinical Microbiology and Infectious Diseases.)

We present the experimental demonstration of a method for generating two spectrally and temporally separated pulses by an externally seeded, single-pass free-electron laser operating in the extreme-ultraviolet spectral range. Our results, collected on the FERMI@Elettra facility and confirmed by numerical simulations, demonstrate the possibility of controlling both the spectral and temporal features of the generated pulses. A free-electron laser operated in this mode becomes a suitable light source for jitter-free, two-colour pump-probe experiments.

Objective: To evaluate safety and durability of once-daily and twice-daily darunavir/ritonavir (DRV/r)-based treatment in HIV patients in clinical practice., Methods: The Surveillance Cohort Long-Term Toxicity Antiretrovirals (SCOLTA) project is a prospective, observational, multicenter cohort created to assess the incidence of adverse events in patients receiving new antiretroviral drugs. Twenty-five Italian infectious diseases centers enroll patients and collect their data through this on-line system. Periodical evaluations of these patients, including physical examination and laboratory tests, were performed at baseline and every 6 months., Results: Four hundred and twenty-nine patients were enrolled since May 2006. Eighty-five patients (19.8%) were prescribed once-daily DRV/r; 31 of them were treatment-naïve (36.5%). Among 54 (63.5%) treatment-experienced patients, 21 (38.9%) had undetectable viral load and started once-daily DRV/r as a simplification regimen. Patients on twice-daily regimen were older, more frequently lipodystrophic, HCV-coinfected, and in CDC stage C. In the following 24 months of follow-up, the viral load steadily decreased as well as the CD4 cell count rose. The reason for discontinuation did not significantly differ between groups. Mean blood glucose (BG) change from baseline did not show significant difference between groups, as well as high density lipoprotein cholesterol (HDL-C), triglycerides (TGL) and alanine transaminase (ALT). The survival curve shows that patients in the once-daily regimen withdrew treatment more frequently than those on twice-daily regimen (Log Rank Chi(2)P=0.009)., Conclusion: Our study showed that DRV/r administrated both once daily or twice daily was safe and well tolerated with few discontinuations due to adverse events., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Objective: HIV infection has been associated with increased cardiovascular risk. Twenty-four-hour ambulatory blood pressure (BP) is a more accurate and prognostically relevant measure of an individual's BP load than office BP, and the ambulatory BP-derived ambulatory arterial stiffness index (AASI) and symmetric AASI (s-AASI) are established cardiovascular risk factors., Methods: In the setting of the HIV and HYpertension (HIV-HY) study, an Italian nationwide survey on high BP in HIV infection, 100 HIV-infected patients with high-normal BP or untreated hypertension (72% men, age 48 ± 10 years, BP 142/91 ± 12/7 mmHg) and 325 HIV-negative individuals with comparable age, sex distribution, and office BP (68% men, age 48 ± 10 years, BP 141/90 ± 11/8 mmHg) underwent 24-h ambulatory BP monitoring., Results: Despite having similar office BP, HIV-infected individuals had higher 24-h SBP (130.6 ± 14 vs. 126.4 ± 10 mmHg) and pulse pressure (49.1 ± 9 vs. 45.9 ± 7 mmHg, both P < 0.001), and a lower day-night reduction of mean arterial pressure (14.3 ± 9 vs. 16.3 ± 7%, P = 0.025). Both s-AASI and AASI were significantly higher in HIV patients (s-AASI, 0.22 ± 0.18 vs. 0.11 ± 0.15; AASI, 0.46 ± 0.22 vs. 0.29 ± 0.17; both P <0.001). In a multivariate regression, s-AASI was independently predicted by HIV infection (β = 0.252, P <0.001), age, female sex, and 24-h SBP. In HIV patients, s-AASI had an inverse relation with CD4 cell count (Spearman's ρ -0.24, P = 0.027)., Conclusion: Individuals with HIV infection and borderline or definite hypertension have higher symmetric AASI and 24-h systolic and pulse pressures than HIV-uninfected controls matched by office BP. High ambulatory BP may play a role in the HIV-related increase in cardiovascular risk.

The longitudinal electron beam properties are of crucial importance for many types of frontier accelerators, from storage rings to free electron lasers and energy recovery linacs. For the online control of the machine and its stable operation, nondestructive shot by shot bunch length measurements are needed. Among the various instrumentations proposed and installed in accelerators worldwide, the ones based on the measurement of the coherent radiation power represent the simplest and the more robust tools for operational control. The major limitation of these systems is that they usually can provide only relative bunch length estimation. In this Letter we present a novel experimental methodology to self-calibrate a simple equipment based on diffraction radiation from a gap providing a measurement of the second order moment of the longitudinal distribution. We present the theoretical basis of the proposed approach and validate it through a detailed campaign of measurements.

We describe the project for the construction of a terahertz (THz) beamline to be called TeraFERMI at the seeded FERMI free electron laser (FEL) facility in Trieste, Italy. We discuss topics as the underlying scientific case, the choice of the source, the expected performance, and THz beam propagation. Through electron beam dynamics simulations we show that the installation of the THz source in the beam dump section provides a new approach for compressing the electron bunch length without affecting FEL operation. Thanks to this further compression of the FEL electron bunch, the TeraFERMI facility is expected to provide THz pulses with energies up to the mJ range during normal FEL operation.

Exploring the dynamics of matter driven to extreme non-equilibrium states by an intense ultrashort X-ray pulse is becoming reality, thanks to the advent of free-electron laser technology that allows development of different schemes for probing the response at variable time delay with a second pulse. Here we report the generation of two-colour extreme ultraviolet pulses of controlled wavelengths, intensity and timing by seeding of high-gain harmonic generation free-electron laser with multiple independent laser pulses. The potential of this new scheme is demonstrated by the time evolution of a titanium-grating diffraction pattern, tuning the two coherent pulses to the titanium M-resonance and varying their intensities. This reveals that an intense pulse induces abrupt pattern changes on a time scale shorter than hydrodynamic expansion and ablation. This result exemplifies the essential capabilities of the jitter-free multiple-colour free-electron laser pulse sequences to study evolving states of matter with element sensitivity.

Objectives: To explore the durability of three first-line tenofovir/emtricitabine-based regimens in combination with atazanavir/ritonavir, efavirenz or lopinavir/ritonavir in HIV-1-infected patients., Patients and Methods: A retrospective, longitudinal, multicentre analysis of adult patients enrolled in the Antiretroviral Resistance Cohort Analysis (ARCA), a national prospective observational cohort of HIV-1-infected patients followed up at more than 100 clinical and laboratory units in Italy. Patients eligible were those starting first-line antiretroviral therapy between 1 June 2004 and 15 April 2011 and who were followed up for at least 6 months. The primary endpoint was durability, defined as the time from antiretroviral therapy initiation to first treatment modification. Time-dependent events were analysed by the Kaplan-Meier approach and the Cox proportional hazard model., Results: There are 26,000 HIV-infected patients in the ARCA database, of whom 1654 met study inclusion criteria. Six hundred and thirty-nine (38.6%) received efavirenz, 321 (19.4%) received atazanavir/ritonavir and 694 (41.9%) received lopinavir/ritonavir as a first-line regimen. Over a total observation period of 88 months, equivalent to more than 2805 person-years of follow-up, 618 patients underwent treatment modification. Lopinavir/ritonavir, given twice daily, was associated with a higher discontinuation rate than efavirenz- and atazanavir-based regimens [hazard ratio (HR) 1.83, 95% confidence interval (CI) 1.56-2.15, P = 0.001]. Comparing the once-daily regimens, the rate of discontinuation of efavirenz was higher than that of atazanavir/ritonavir (HR 1.39, 95% CI 1.06-1.83, P = 0.016)., Conclusions: Significant differences in treatment duration were observed among the three studied regimens. Once-daily regimens exhibited greater durability than the twice-daily regimen. Among the specific regimens examined, tenofovir/emtricitabine plus atazanavir/ritonavir showed the greatest durability.

The prevalence of HIV-1 integrase mutations related to resistance to the next-generation integrase inhibitor (INI), dolutegravir (DTG), was assessed in 440 INI-naïve subjects and in 120 patients failing a raltegravir (RTG)-containing regimen. Of the mutations selected by DTG in vitro, S153FY was not detected in any isolate while L101I and T124A were highly prevalent in both groups and significantly associated with non-B subtype. RTG-selected double and triple mutants, mostly the G140S/Q148H variant, were detected in only 32 (26.7%) RTG-treated patients. As L101I and T124A do not appear to exert any major effect in vivo and double and triple mutants resistant to DTG are infrequently selected by RTG, DTG can be effectively used in INI-naïve patients and may retain activity in many patients failing RTG., (© 2012 The Authors. Clinical Microbiology and Infection © 2012 European Society of Clinical Microbiology and Infectious Diseases.)

Prevalence and predictors of transmitted drug resistance (TDR), defined as the presence of at least one WHO surveillance drug resistance mutation (SDRM), were investigated in antiretroviral-naïve HIV-1-infected patients, with a genotypic resistance test (GRT) performed ≤6 months before starting cART between 2000 and 2010. 3163 HIV-1 sequences were selected (69% subtype B). Overall, the prevalence of TDR was 12% (13.2% subtype B, 9% non-B). TDR significantly declined overall and for the single drug classes. Older age independently predicted increased odds of TDR, whereas a more recent GRT, a higher HIV-RNA and C vs. B subtype predicted lower odds of TDR., (© 2012 The Authors. Clinical Microbiology and Infection © 2012 European Society of Clinical Microbiology and Infectious Diseases.)

Metabolic Syndrome (MS) is a common disorder combining obesity, dyslipidemia, hypertension, and insulin resistance. Its prevalence among HIV-infected people is still debated. Besides, how antiretroviral therapy and HIV infection per se are related to MS is still unclear. All treatment-naïve patients attending scheduled visits at CISAI group hospitals between January and December 2007 were eligible for the study. Patients without MS at enrolment were followed-up for 3 years or until they developed MS, diagnosed according to the National Cholesterol Education Program (NCEP) definition. The main objective was to assess the 3-years incidence of MS. MS was evaluated for 188 subjects. Out of them, 62 (33.0%) had started HAART at enrolment, whereas 67 (35.6%) more started during the observation. 59 (31.4%) were still treatment-naive at the study end. MS was newly diagnosed in 14 patients. The incidence was 2.60 cases/100 person-years (95% CI 1.47-4.51), 2.75 (1.11-5.72) among HAART-naïve patients and 2.65 (1.23-5.03) in subjects on HAART. Blood pressure did not change in the study period, whereas in naive patients the HDL level significantly lowered (median -6.0 vs. 4.0, P<0.0001) compared to HAART-treated patients. Triglicerides increased significantly in HAART subjects (median 12.0 vs. 1.0, P=0.02), as well as blood glucose (median 6.0 vs. 1.0, P=0.01). In our population, the overall MS incidence was low and largely similar in patients who started HAART or remained naive. However, the feature of MS was different in the two groups, suggesting that in untreated and treated patients MS developed through different metabolic pathways., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)