Dynamics and phylogenetic relationships of HIV-1 transmitted drug resistance according to subtype in Italy over the years 2000-14.

Background: Transmitted drug-resistance (TDR) remains a critical aspect for the management of HIV-1-infected individuals. Thus, studying the dynamics of TDR is crucial to optimize HIV care. Methods: In total, 4323 HIV-1 protease/reverse-transcriptase sequences from drug-naive individuals diagnosed in north and central Italy between 2000 and 2014 were analysed. TDR was evaluated over time. Maximum-likelihood and Bayesian phylogenetic trees with bootstrap and Bayesian-probability supports defined transmission clusters. Results: Most individuals were males (80.2%) and Italian (72.1%), with a median (IQR) age of 37 (30-45) years. MSM accounted for 42.2% of cases, followed by heterosexuals (36.4%). Non-B subtype infections accounted for 30.8% of the overall population and increased over time (<2005-14: 19.5%-38.5%, P < 0.0001), particularly among Italians (<2005-14: 6.5%-28.8%, P < 0.0001). TDR prevalence was 8.8% and increased over time in non-B subtypes (<2005-14: 2%-7.1%, P = 0.018). Overall, 467 transmission clusters (involving 1207 individuals; 27.9%) were identified. The prevalence of individuals grouping in transmission clusters increased over time in both B (<2005-14: 12.9%-33.5%, P = 0.001) and non-B subtypes (<2005-14: 18.4%-41.9%, P = 0.006). TDR transmission clusters were 13.3% within the overall cluster observed and dramatically increased in recent years (<2005-14: 14.3%-35.5%, P = 0.005). This recent increase was mainly due to non-B subtype-infected individuals, who were also more frequently involved in large transmission clusters than those infected with a B subtype [median number of individuals in transmission clusters: 7 (IQR 6-19) versus 4 (3-4), P = 0.047]. Conclusions: The epidemiology of HIV transmission changed greatly over time; the increasing number of transmission clusters (sometimes with drug resistance) shows that detection and proper treatment of the multi-transmitters is a major target for controlling HIV spread.

Construction of the B88 Exchange-Energy Functional in Two Dimensions.

We construct a generalized-gradient approximation for the exchange-energy density of finite two-dimensional systems. Guided by nonempirical principles, we include the proper small-gradient limit and the proper tail for the exchange-hole potential. The observed performance is superior to that of the two-dimensional local-density approximation, which underlines the usefulness of the approach in practical applications.

Electron-electron interactions in artificial graphene.

Recent advances in the creation and modulation of graphenelike systems are introducing a science of "designer Dirac materials". In its original definition, artificial graphene is a man-made nanostructure that consists of identical potential wells (quantum dots) arranged in an adjustable honeycomb lattice in the two-dimensional electron gas. As our ability to control the quality of artificial graphene samples improves, so grows the need for an accurate theory of its electronic properties, including the effects of electron-electron interactions. Here we determine those effects on the band structure and on the emergence of Dirac points.

Exact conditions in finite-temperature density-functional theory.

Density-functional theory (DFT) for electrons at finite temperature is increasingly important in condensed matter and chemistry. The exact conditions that have proven crucial in constraining and constructing accurate approximations for ground-state DFT are generalized to finite temperature, including the adiabatic connection formula. We discuss consequences for functional construction.

[Strategies for prevention and control of healthcare related infections by Acinetobacter baumannii]. / Strategie di prevenzione e controllo delle infezioni da Acinetobacter baumannii correlate all'assistenza sanitaria.

The frequent development of acquired antibiotics resistance in bacteria represents a challenge for Public Health in terms of healthcare associated infections control. Apart from the appropriate use of drugs, in particular the choice of proper antimicrobial therapy, increasing interest is, therefore, given to the non-pharmacological prevention of these infections. Acinetobacter (A.) baumannii is a micoorganism that commonly causes infections for patients hospitalized in critical hospital wards (intensive care units, burn centers, surgery, neonatology, etc) potentially severe and difficult to treat, because A. baumannii is resistant to many or sometimes all, available antibiotics (PDR - pan drug resistant). The aim of the present paper was to review the available measures for preventing and controlling the contamination and the spread of these types of bacterial infections in health care scenarios, with particular attention to two methods that stand out for efficiency and safety: hand hygiene and environmental disinfection.

[NDM-1: the superbug?]. / NDM-1: il superbug?

A novel type of carbapenemase, New Delhi metallo beta-lactamase 1 (NDM 1), was first identified in 2008 in two Enterobacteriacea isolates, both recovered from a Swedish patient transferred from India. The emergence of NDM 1 is now reported from all continents, often in patients with a history of travel or hospitalization in the Indian subcontinent. The NDM 1 producing Gram-negative bacteria are mainly Enterobacteriaceae, which can cause colonization or fatal infections, with worrying antimicrobial susceptibility profiles: some isolates have developed resistance to practically all available antibiotics. Is the NDM-1 the super-bug? Are we in the post-antibiotic era? This review is a summary of currently available knowledge of NDM-1 that draws attention to future antimicrobial resistance scenarios.

Universal correction for the Becke-Johnson exchange potential.

The Becke-Johnson exchange potential [A. D. Becke and E. R. Johnson, J. Chem. Phys. 124, 221101 (2006)] has been successfully used in electronic structure calculations within density-functional theory. However, in its original form, the potential may dramatically fail in systems with non-Coulombic external potentials, or in the presence of external magnetic or electric fields. Here, we provide a system-independent correction to the Becke-Johnson approximation by (i) enforcing its gauge-invariance and (ii) making it exact for any single-electron system. The resulting approximation is then better designed to deal with current-carrying states and recovers the correct asymptotic behavior for systems with any number of electrons. Tests of the resulting corrected exchange potential show very good results for a hydrogen chain in an electric field and for a four-electron harmonium in a magnetic field.

Lower bounds on the exchange-correlation energy in reduced dimensions.

Bounds on the exchange-correlation energy of many-electron systems are derived and tested. By using universal scaling properties of the electron-electron interaction, we obtain the exponent of the bounds in three, two, one, and quasione dimensions. From the properties of the electron gas in the dilute regime, the tightest estimate to date is given for the numerical prefactor of the bound, which is crucial in practical applications. Numerical tests on various low-dimensional systems are in line with the bounds obtained and give evidence of an interesting dimensional crossover between two and one dimensions.

Hygiene precautions and the transmission of infections in radiology.

Healthcare-associated infections are a critical challenge for the public health sector. Most are acquired through contact, predominantly with the hands of health care personnel. Hand hygiene, therefore, is the single most effective measure for preventing and controlling infectious diseases. Recently, cases of acute hepatitis C occurred in patients who had undergone contrast-enhanced computed tomography. This was probably related to inadequate handling by health care staff. Rigorous compliance with standard precautions is therefore compulsory even in radiology, a setting traditionally considered at low risk for the transmission of pathogens. Adherence to standard precautions is still poor and the persistence of inappropriate practices responsible for preventable incidents is very common in radiology, often owing to underestimation of risk. Radiology units must promote compliance with correct hand hygiene through appropriate education programmes and provision of adequate areas and hand hygiene products. The evidence base to support the use of alcohol-based hand rub is demonstrating that these formulations are effective in improving hand hygiene compliance and preventing infections.

Multiband superconductivity in Pb, H under pressure and CaBeSi from ab initio calculations.

Superconductivity in Pb, H under extreme pressure and CaBeSi, in the framework of the density functional theory for superconductors, is discussed. A detailed analysis on how the electron-phonon and electron-electron interactions combine together to determine the superconducting gap and critical temperature of these systems is presented. Pb, H under pressure and CaBeSi are multigap superconductors. We will address the question under which conditions does a system exhibits this phenomenon. The presented results contribute to the understanding of multiband and anisotropic superconductivity, which has received a lot of attention since the discovery of MgB(2), and show how it is possible to describe the superconducting properties of real materials on a fully ab initio basis.

Orbital currents in the Colle-Salvetti correlation energy functional and the degeneracy problem.

Popular density functionals for the exchange-correlation energy typically fail to reproduce the degeneracy of different ground states of open-shell atoms. As a remedy, functionals which explicitly depend on the current density have been suggested. We present an analysis of this problem by investigating functionals that explicitly depend on the Kohn-Sham orbitals. Going beyond the exact-exchange approximation by adding correlation in the form of the Colle-Salvetti functional, we show how current-dependent terms enter the Colle-Salvetti expression and their relevance is evaluated. A very good description of the degeneracy of ground states for atoms of the first and second rows of the Periodic Table is obtained.

First-principles approach to noncollinear magnetism: towards spin dynamics.

A description of noncollinear magnetism in the framework of spin-density functional theory is presented for the exact exchange energy functional which depends explicitly on two-component spinor orbitals. The equations for the effective Kohn-Sham scalar potential and magnetic field are derived within the optimized effective potential (OEP) framework. With the example of a magnetically frustrated Cr monolayer it is shown that the resulting magnetization density exhibits much more noncollinear structure than standard calculations. Furthermore, a time-dependent generalization of the noncollinear OEP method is well suited for an ab initio description of spin dynamics. We also show that the magnetic moments of solids Fe, Co, and Ni are well reproduced.

Imported malaria at Italy's National Institute for Infectious Diseases Lazzaro Spallanzani, 1984-2003.

Imported malaria is the most common cause of fatal infections in returning travellers. The increased amount of both tourist movement and migration has resulted in a growing number of people at risk of infection. In the present study, 507 malaria patients admitted to Italy's National Institute for Infectious Diseases in Rome between January 1984 and December 2003 were studied. Overall, 445 cases, or 87.7%, were acquired in Africa, of which 55% were acquired in five sub-Saharan countries. Plasmodium falciparum accounted for 393 (77.5%) of the imported cases. Patients consisted of short-term travellers (n = 213, 42%), long-term visitors (n = 134, 26.4%), and immigrants from endemic areas (n = 137, 27%). Malaria chemoprophylaxis was completed in less than one-quarter of all patients, with immigrants having the lowest rate of completion: only 3.6% of immigrants fully completed chemoprophylaxis compared to 31% of short-term travellers and 29.1% of long-term visitors (p < 0.001). Upon multivariate analysis, the lack of chemoprophylaxis was independently associated with the occurrence of severe malaria (p = 0.009). Severe malaria was reported in 59 (11.6%) individuals: all 11 deaths due to severe P. falciparum infection occurred in patients from sub-Saharan countries, two of whom were immigrants from countries where malaria is endemic. Malaria poses a serious health threat to individuals visiting endemic areas. Ensuring the correct chemoprophylaxis for all travellers, including immigrants from endemic areas, and providing prompt access to healthcare providers for unhealthy returning travellers are major points still to be addressed in Italy.

On the degeneracy of atomic states within exact-exchange (spin-) density functional theory.

The problem of degenerate ground states of open-shell atoms is investigated in spin-restricted and spin-unrestricted density functional theories using the exact-exchange energy functional. For the spin-unrestricted case, spurious energy splittings of the order of 2-3 kcal/mol are found for atoms of the second and third periods which are larger than the splittings obtained from recently proposed approximate exchange functionals depending explicitly on the current density. In remarkable contrast, for spin-restricted calculations the degeneracy of different atomic ground states is recovered to within less than 0.6 kcal/mol.

Interleukin-12 in early or advanced cancer patients.

Interleukin-2 (IL-2) and interleukin-12 (IL-12) may represent the most important antitumour cytokines in human neoplasms. IL-2 blood levels decrease in advanced solid malignancies, but currently there are no data on IL-12 secretion in cancer patients. This study was performed to obtain preliminary data about IL-12 secretion in patients with solid malignant tumours, either in relation to the extension of disease, or to other cytokines, including IL-2, IL-6 and IL-10. The study included 40 solid cancer patients, 24 of whom showed distant organ metastases. Cytokine serum levels were measured by an enzyme immunoassay of blood samples collected during the morning. No patient had abnormally low levels of IL-12, but the levels were high in 14/14 (35%) patients. Mean levels of IL-12 were significantly higher in metastatic patients compared with non-metastatic patients (P < 0.05). Moreover, metastatic patients with high blood concentrations of IL-12 showed significantly lower levels of IL-10 than metastatic patients with normal IL-12 values, while no difference was seen in IL-2 mean concentrations. IL-6 mean levels were lower in metastatic patients with increased IL-12 levels, but this was non-significant. This preliminary study shows that advanced solid cancers are not characterised by a diminished secretion of IL-12, but rather IL-12 levels tend to be abnormally high in metastatic cancer patients.

Prevention of cytokine-induced hypotension in cancer patients by the pineal hormone melatonin.

Hypotension is a frequent side-effect of cancer biotherapies with cytokines. Cytokine-induced hypotension would mainly depend on the stimulation of nitric oxide (NO) production, which represents the most effective endogenous vasodilator. Moreover, it has been proven that both biological activity and toxicity of cytokines are influenced by the psychoneuroendocrine system, in particular by the pineal hormone melatonin. To investigate the possible modulatory effect of melatonin on cytokine cardiovascular toxicity, we evaluated the influence of a concomitant melatonin administration on interleukin-2(IL-2)- and tumour-necrosis-factor-alpha(TNF)-induced hypotension in advanced cancer patients. The study included 116 patients with advanced solid tumour, for whom no effective standard anticancer therapy was available, who underwent cancer biotherapy with IL-2 (3 x 10(6) IU/ day s.c. every day, 6 days/week for 4 weeks) or with TNF (0.75 mg/day i.v. for 5 days) as compassionate treatment for their disease. Patients were randomized to be treated with or without a concomitant melatonin administration (40 mg/day orally in the evening, starting 7 days prior to cytokine injection). The occurrence of hypotension was significantly less frequent in patients concomitantly treated by melatonin than in those who received the cytokine alone, during either IL-2: or TNF immunotherapy (IL-2; 11/45 versus 2/46, P < 0.05; TNF: 10/23 versus 1/12, P < 0.01). This study shows that melatonin may prevent hypotension occurring during cancer immunotherapy with IL-2 or TNF. Since the pineal hormone has appeared to inhibit the activity of NO synthase from the endothelial cells, we suggest that melatonin may prevent cytokine-induced hypotension by inhibiting NO production, which plays an essential role in inducing hypotension during IL-2 and TNF biotherapies.