Efficacy of non-invasive mechanical ventilation in the general ward in patients with chronic obstructive pulmonary disease admitted for hypercapnic acute respiratory failure and pH < 7.35: a feasibility pilot study.

AIM: To date non-invasive (NIV) mechanical ventilation use is not recommended in chronic obstructive pulmonary disease (COPD) patients with acute respiratory failure (ARF) and pH < 7.30 outside a 'protected environment'. We assessed NIV efficacy and feasibility in improving arterial blood gases (ABG) and in-hospital outcome in patients with ARF and severe respiratory acidosis (RA) admitted to an experienced rural medical ward. METHODS: This paper is a prospective pilot cohort study conducted in the General Medicine Ward of Budrio's District Hospital. Two hundred and seventy-two patients with ARF were admitted to our Department, 112, meeting predefined inclusion criteria (pH < 7.35, PaCO2 > 45 mmHg). Patients were divided according to the severity of acidosis into: group A (pH < 7.26), group B (7.26 ≤ pH < 7.30) and group C (7.30 ≤ pH < 7.35). ABG were assessed at admission, at 2-6 h, 24 h, 48 h and at discharge. RESULTS: Group A included 55 patients (24 men, mean age: 80.8 ± 8.3 years), group B 31 (12 men, mean age: 80.3 ± 9.4 years) and group C 26 (15 men, mean age: 78.6 ± 9.9 years). ABG improved within the first hours in 92/112 (82%) patients, who were all successfully discharged. Eighteen percent (20/112) of the patients died during the hospital stay, no significant difference emerged in mortality rate (MR) within the groups (23%, 16% and 8%, for groups A, B and C, respectively) and between patients with or without pneumonia: 8/29 (27%) versus 12/83 (14%). On multivariable analysis, only age and Glasgow Coma Scale had an impact on the clinical outcome. CONCLUSION: In a non-'highly protected' environment such as an experienced medical ward of a rural hospital, NIV is effective not only in patients with mild, but also with severe forms of RA. MR did not vary according to the level of initial pH.

Possible role of tocopherols in the modulation of host microRNA with potential antiviral activity in patients with hepatitis B virus-related persistent infection: a systematic review.

Hepatitis B virus (HBV) infection represents a serious global health problem and persistent HBV infection is associated with an increased risk of cirrhosis, hepatocellular carcinoma and liver failure. Recently, the study of the role of microRNA (miRNA) in the pathogenesis of HBV has gained considerable interest as well as new treatments against this pathogen have been approved. A few studies have investigated the antiviral activity of vitamin E (VE) in chronic HBV carriers. Herein, we review the possible role of tocopherols in the modulation of host miRNA with potential anti-HBV activity. A systematic research of the scientific literature was performed by searching the MEDLINE, Cochrane Library and EMBASE databases. The keywords used were 'HBV therapy', 'HBV treatment', 'VE antiviral effects', 'tocopherol antiviral activity', 'miRNA antiviral activity' and 'VE microRNA'. Reports describing the role of miRNA in the regulation of HBV life cycle, in vitro and in vivo available studies reporting the effects of VE on miRNA expression profiles and epigenetic networks, and clinical trials reporting the use of VE in patients with HBV-related chronic hepatitis were identified and examined. Based on the clinical results obtained in VE-treated chronic HBV carriers, we provide a reliable hypothesis for the possible role of this vitamin in the modulation of host miRNA profiles perturbed by this viral pathogen and in the regulation of some cellular miRNA with a suggested potential anti-HBV activity. This approach may contribute to the improvement of our understanding of pathogenetic mechanisms involved in HBV infection and increase the possibility of its management and treatment.

Acanthosis nigricans in adolescents: a practical approach.

Acanthosis nigricans (AN) is a lesion affecting localized areas of the skin in persons with obesity and/or hyperinsulinemia. Biochemical mechanisms responsible for developing this hyperplastic lesion are unclear, but likely involve local cutaneous growth factors. It is associated with obesity, endocrinopathies (insulin resistance, diabetes mellitus, Cushing disease and acromegaly) and visceral malignancies. Clinicians should recognize AN because it may herald disorders ranging from endocrine disturbances to malignancy. Early recognition of these conditions is essential to identify children who are at highest risk for developing type 2 diabetes and further metabolic abnormalities.

Photoreceptors for a light biotransducer: a comparative study of the electrical responses of two (type-1) opsins.

The increasing interest in photoactivated proteins as natural replacements for standard inorganic materials in photocells leads to the comparison analysis of bacteriorhodopsin and proteorhodopsin, two widely diffused proteins belonging to the family of type-1 opsins. These proteins share similar behaviors but exhibit relevant differences in the sequential chain of the amino acids constituting their tertiary structure. The use of an impedance network analog to model the protein main features provides a microscopic interpretation of a set of experiments on their photo-conductance properties. In particular, this model links the protein electrical responses to the tertiary structure and to the interactions between neighboring amino acids. The same model is also used to predict the small-signal response in terms of the Nyquist plot. Interestingly, these rhodopsins are found to behave like a wide-gap semiconductor with intrinsic conductivities of the order of 10⁻7 S cm⁻¹.

Evidence of Gumbel distributions of conductance fluctuations in bacteriorhodopsin thin films.

By considering a set of experiments carried out on bacteriorhodopsin in vitro by Casuso et al (2007 Phys. Rev. E 76 041919), we extract the conductance as function of the applied voltage. The microscopic interpretation of experiments shows that charge transfer is ruled by a direct tunneling (DT) mechanism at low bias and by a Fowler­Nordheim (FN) tunneling mechanism at high bias. A nucleation region at the cross-over between the DT and FN regimes can be identified. A theoretical analysis of conductance fluctuations is performed by calculating the corresponding variance and the probability density functions (PDFs): these constitute a powerful indicator in order to understand the internal dynamics of the system. Conductance fluctuations are non-Gaussian and follow well the standard generalized Gumbel distributions G(a). In particular, at low bias, the PDFs are bimodal and can be resolved in at least a couple of G(a) functions with different values of the shape parameter a. The nucleation region is characterized by a single Gumbel distribution, G(1). At increasing bias, the G(1) distribution turns in a bimodal distribution. We discuss possible correlations between the voltage dependence of the G(a) and the microscopic mechanisms that determine the electrical response of the system.

Association between hepatitis B or hepatitis C virus infection and risk of pancreatic adenocarcinoma development: a systematic review and meta-analysis.

BACKGROUND: Pancreatic adenocarcinoma (PAC) is an aggressive cancer with a poor prognosis. To date, PAC causes are still largely unknown. Antigens and replicative sequences of oncogenic hepatitis B (HBV) and hepatitis C (HCV) virus were detected in different extra-hepatic tissues, including pancreas. OBJECTIVE: a systematic review and meta-analysis of epidemiological studies assessing PAC risk in patients with HBV/HCV chronic infections. METHODS: In September 2012, we extracted the articles published in Medline, Embase and the Cochrane Library, using the following search terms: "chronic HBV" and "HCV", "hepatitis", "PAC", "risk factors", "epidemiology". Only case/control (C/C), prospective/retrospective cohort studies (PCS/RCS) written in English were collected. RESULTS: four hospital-based C/C studies and one PCS, in HBV-infected patients and two hospital-based C/C studies and one RCS in HCV-infected subjects met inclusion criteria. In these studies HBsAg positivity enhanced significantly PAC risk (RR = 1.18, 95% CI:1.04-1.33), whereas HBeAg positivity (RR = 1.31, 95% CI:0.85-2.02) as well as HBsAg negative/HBcAb positive/HBsAb positive pattern (RR = 1.12, 95% CI:0.78-1.59) and HBsAg negative/HBcAb positive/HBsAb negative pattern (RR = 1.30, 95% CI:0.93-1.84) did not. Relationship between PAC risk and anti-HCV positivity was not significant, although it reached a borderline value (RR = 1.160, 95% CI:0.99-1.3). CONCLUSIONS: HBV/HCV infection may represent a risk factor for PAC, but the small number of available researches, involving mainly populations of Asian ethnicity and the substantial variation between different geographical areas in seroprevalence of HBV/HCV-antigens/antibodies and genotypes are limiting factors to present meta-analysis.

Quantum maximum entropy principle for fractional exclusion statistics.

Using the Wigner representation, compatibly with the uncertainty principle, we formulate a quantum maximum entropy principle for the fractional exclusion statistics. By considering anyonic systems satisfying fractional exclusion statistic, all the results available in the literature are generalized in terms of both the kind of statistics and a nonlocal description for excluson gases. Gradient quantum corrections are explicitly given at different levels of degeneracy and classical results are recovered when ℏ→0.

Adolescent health care in Italy: a mini-review.

The purpose of this mini-review is to present the National Health System and services available for adolescents in Italy, and to review the most relevant data on morbidity and mortality in Italian teens. Adolescent medicine in Italy is not a separate speciality, but there are some distinct services for adolescents in paediatric departments or gynaecologic wards, mostly in large cities where university hospitals or hospital of national relevance are located. Primary health care in Italy is provided mainly by general practitioners (GPs) and pediatricians, and on-call physicians (Guardia Medica) for after-hours medical care and services. The number of centres providing care for adolescents in Italy is 4097 (50% of these are in the North of Italy, 20% in the Central regions and 20% in the South and Islands). The population of Italy on January 1st 2011 was approximately 60,477,881 and the number of adolescents, aged 10 to 19 years, was 6,214,000. The most frequent causes of death in adolescents are motor vehicle accidents - more than half of which are related to drug or alcohol use - followed by cancer and suicide. In primary care, adolescents present with a large number of issues, particularly upper respiratory infections, musculoskeletal problems, pain syndromes, obesity, eating disorders, dermatological issues, mood and somatoform disorders, school and mental health problems, and chronic fatigue, many of which require a coordinated, multidisciplinary management approach. The estimated population with a chronic illness is 8%. There are no specific protocols for the transition to adult medicine physicians for patients with chronic diseases or special health needs. In order to improve the quality and quantity of education in adolescent health for paediatricians and GPs, the Study Group of Emilia and Romagna Region for Adolescent Health Care (SGA-ER) is going to organize, beginning in 2012, a two year educational intervention course in adolescent health.

The SGA-ER educational intervention in adolescent health care for Italian physicians: goals, content and instructional design.

Adolescent medicine is a field dedicated to helping young people grow and thrive, in relation to their particular stage of development. In Italy, adolescent medicine is not a distinct speciality, but it is practised in some services for adolescents in paediatric departments. Increasing educational opportunities in adolescent health may help to accelerate the development and dissemination of new and improved therapeutic approaches for serving youth and also attract a larger cadre of physicians. Other pediatric subspecialties, e.g. oncology, rheumatology and adolescent psychiatry, have developed successfully and may represent excellent models for adolescent medicine specialists to emulate. The Adolescent Health Study Group of the Emilia and Romagna Region (SGA-ER) was established in 2010 in an effort to generate strategies and possible solutions to improve the quality and quantity of knowledge in adolescent health care for pediatricians and GPs. Several methods and approaches have been implemented to improve physicians' skills in adolescent health care. The authors report the goals, content and instructional design of an educational course in adolescent medicine. Alliances with other adolescent health groups may provide an additional opportunity for networking, interaction and exchange of ideas amongst professionals.

ASN540SER mutation is associated with a mild form of hypochondroplasia: a 7 years follow-up in an Italian boy.

Skeletal dysplasias (SKD) are genetic disorders that result in the abnormal development of part or all of the skeleton and are commonly associated with short stature. The most common SKDs that typically result in short stature include achondroplasia/hypochondroplasia (HCH) both caused by different mutations in the same gene. HCH diagnosis is based on the clinical appearance during development and conventional X-ray findings. In about 70% of patients, missense mutations in the gene coding for the fibroblast Growth Factor Receptor 3 (FGFR3) affects the amino acid at position 540, mostly resulting in the amino acid exchange N540K.Subjects with HCH, heterozygous for the N540K substitution are significantly more disproportionate than individuals without this mutation. We report the clinical and radiographic features of an Italian family with HCH with an unusual N540S mutation, inside the common mutation hot spot of this condition. This is the first case reported in Italy and the third in the literature. During a 7-years-follow-up, the boy started the puberty at the age of 11.3 years and the growth spurt was observed between 13.7 and 14.9 years (+ 9.1 cm.).During pubertal development the sitting height (SDS) improved from - 1.5 to - 0.6 and the subischial leg length (SDS) progressed from - 2.6 to - 3.3.At the age of 16.7 year the standing height was 157.6 cm ( - 2.4 SDS), testicular volume was 15 ml and bone age 16.5 year. The present study and the other two cases reported in the literature stress the important role of the asn 540 site in the tyrosine kinase I domain in the pathogenesis of HCH and underline the importance that, in patients with HCH who do not have the common N540K mutation, sequence analysis of the tyrosine kinase I domain of FGFR3 should be performed to exclude other changes in that region.

Hepatitis B and C virus infections as possible risk factor for pancreatic adenocarcinoma.

Pancreatic adenocarcinoma (PAC) is a very aggressive and lethal cancer, with a very poor prognosis, because of absence of early symptoms, advanced stage at presentation, early metastatic dissemination and lack of both specific tests to detect its growth in the initial phases and effective systemic therapies. To date, the causes of PAC still remain largely unknown, but multiple lines of evidence from epidemiological and laboratory researches suggest that about 15-20% of all cancers are linked in some way to chronic infection, in particular it has been shown that several viruses have a role in human carcinogenesis. The purpose of this report is to discuss the hypothesis that two well-known oncogenic viruses, Human B hepatitis (HBV) and Human C hepatitis (HCV) are a possible risk factor for this cancer. Therefore, with the aim to examine the potential link between these viruses and PAC, we performed a selection of observational studies evaluating this association and we hypothesized that some pathogenetic mechanisms involved in liver carcinogenesis might be in common with pancreatic cancer development in patients with serum markers of present or past HBV and HCV infections. To date the available observational studies performed are few, heterogeneous in design as well as in end-points and with not univocal results, nevertheless they might represent the starting-point for future larger and better designed clinical trials to define this hypothesized relationship. Should these further studies confirm an association between HBV/HCV infection and PAC, screening programs might be justified in patients with active or previous hepatitis B and C viral infection.

Charge transport in purple membrane monolayers: a sequential tunneling approach.

Current-voltage (I-V) characteristics in proteins are sensitive to conformational changes induced by an external stimulus (photons, chemical, etc.). This sensitivity can be used in medical and industrial applications as well as shedding new light on the microscopic structure of biological materials. Here, we show that a sequential tunneling model of carrier transfer between neighboring amino acids in a single protein is the basic mechanism responsible for the electrical properties measured over a wide range of applied potentials. We also show that such a strict correlation between the protein structure and the electrical response can lead to a new generation of nanobiosensors that mimic the sensorial activity of living species. To demonstrate the potential usefulness of protein electrical properties, we provide a microscopic interpretation of recent I-V experiments carried out in bacteriorhodopsin at a nanoscale length.

Quantum maximum-entropy principle for closed quantum hydrodynamic transport within a Wigner function formalism.

By introducing a quantum entropy functional of the reduced density matrix, the principle of quantum maximum entropy is asserted as fundamental principle of quantum statistical mechanics. Accordingly, we develop a comprehensive theoretical formalism to construct rigorously a closed quantum hydrodynamic transport within a Wigner function approach. The theoretical formalism is formulated in both thermodynamic equilibrium and nonequilibrium conditions, and the quantum contributions are obtained by only assuming that the Lagrange multipliers can be expanded in powers of h(2). In particular, by using an arbitrary number of moments, we prove that (1) on a macroscopic scale all nonlocal effects, compatible with the uncertainty principle, are imputable to high-order spatial derivatives, both of the numerical density n and of the effective temperature T; (2) the results available from the literature in the framework of both a quantum Boltzmann gas and a degenerate quantum Fermi gas are recovered as a particular case; (3) the statistics for the quantum Fermi and Bose gases at different levels of degeneracy are explicitly incorporated; (4) a set of relevant applications admitting exact analytical equations are explicitly given and discussed; (5) the quantum maximum entropy principle keeps full validity in the classical limit, when h → 0.

Quantum maximum entropy principle for a system of identical particles.

By introducing a functional of the reduced density matrix, we generalize the definition of a quantum entropy which incorporates the indistinguishability principle of a system of identical particles. With the present definition, the principle of quantum maximum entropy permits us to solve the closure problem for a quantum hydrodynamic set of balance equations corresponding to an arbitrary number of moments in the framework of extended thermodynamics. The determination of the reduced Wigner function for equilibrium and nonequilibrium conditions is found to become possible only by assuming that the Lagrange multipliers can be expanded in powers of variant Planck's over 2pi(2). Quantum contributions are expressed in powers of variant Planck's over 2pi(2) while classical results are recovered in the limit variant Planck's over 2pi-->0 .

Role of topology in electrical properties of bacterio-rhodopsin and rat olfactory receptor I7.

We report on electrical properties of the two sensing proteins: bacteriorhodopsin and rat olfactory receptor OR-I7. As relevant transport parameters we consider the small-signal impedance spectrum and the static current-voltage characteristics. Calculations are compared with available experimental results and the model predictability is tested for future perspectives.

Terahertz generation in nitrides due to transit-time resonance assisted by optical phonon emission.

The conditions for THz radiation generation caused by electron transit-time resonance in momentum and real spaces under optical phonon emission are analyzed for nitride-based materials and their structures. It is shown that such a mechanism provides a unique possibility to realize sub-THz and THz radiation generation at the border between the electro-optical and electronic techniques by using two alternative approaches: (i) amplification of transverse electromagnetic waves in 3D bulk materials and 2D quantum wells, and (ii) longitudinal current-field instabilities in sub-micron and micron n(+)nn(+) diodes. Estimations of frequency regions, output power and efficiency of the generation demonstrate that nitrides are promising materials for THz radiation generation.

Terahertz oscillations in ultra-thin n-In(0.53)Ga(0.47)As ungated channels.

Using a self-consistent Monte Carlo simulator we investigate the spectrum of voltage fluctuations of an n-type InGaAs two-terminal layer of variable thickness W in the range 1-100 nm and variable length L in the range 0.01-10 µm embedded in an external dielectric medium. Calculations are performed at T = 300 K for different dopings and in the presence of an external bias of increasing strength. When the bias is well below the threshold for the Gunn effect the spectrum peaks at the plasma oscillations of the electron gas. For W≥100 nm and carrier concentrations of 10(17)-10(18) cm(-3) the peaks are in good agreement with the standard three-dimensional (3D) expression of the plasma frequency. For W≤10 nm the results exhibit a plasma frequency that depends on the length of the layer, thus implying that the oscillation mode is dispersive. The corresponding frequency covers a wide range of values 0.1-10 THz and is in agreement with the two-dimensional (2D) expression of the plasma frequency obtained for a collisionless regime within the in-plane approximation for the electric field. A region of cross-over between the 2D and 3D behaviours of the plasma frequency is shown for W>10 nm. When the bias is above the threshold for the Gunn effect, we observe the washing out of the plasma peak and the onset of a frequency peak associated with the transit time of the Gunn domain located in the sub-terahertz frequency region.

Nanoscale electrical conductivity of the purple membrane monolayer.

Nanoscale electron transport through the purple membrane monolayer, a two-dimensional crystal lattice of the transmembrane protein bacteriorhodopsin, is studied by conductive atomic force microscopy. We demonstrate that the purple membrane exhibits nonresonant tunneling transport, with two characteristic tunneling regimes depending on the applied voltage (direct and Fowler-Nordheim). Our results show that the purple membrane can carry significant current density at the nanometer scale, several orders of magnitude larger than previously estimated by macroscale measurements.