Gastric Antral Vascular Ectasia (GAVE) a case report, review of the literature and update of techniques.

INTRODUCTION AND IMPORTANCE: Gastric Antral Vascular Ectasia is a rare disorder that causes up to 4 % of severe acute gastrointestinal bleeding. It affects elderly females with iron deficiency anemia due to chronic blood loss as a common presenting sign. CASE PRESENTATION: We report the case of a 70-year-old man admitted to the Urgency Department for severe asthenia associated with abdominal pain and severe anemia. An urgent upper endoscopic examination showed antral hyperemic streaks and vascular ectasias extending from the pyloric ring to the gastric body as well as signs of recent bleeding. Histological results demonstrated the pathognomonic features of GAVE. CLINICAL DISCUSSION: The first line treatment is considered argon plasma coagulation (APC), given its wider availability, safety, efficacy and cost-effectiveness. In current literature, other therapies and different types of endoscopic treatments have been proposed, such as EBL, RFA and Yag: laser. To date, there is no specific recommendation that privileges one method over another in the treatment of GAVE, although APC has proven effective and even better in terms of complications and costs than the other techniques. CONCLUSION: In our experience, endoscopic coagulation with APC probes is a relatively easy-to-use technique with low cost, minimal invasiveness and provides immediate results. On the other hand, a standardized algorithm is also required concerning to the different subtypes to give the best treatment in every case.

Prevalence of FoxP3(+) Cells in Canine Tumours and Lymph Nodes Correlates Positively with Glucose Transporter 1 Expression.

Hypoxia and regulatory T cells (Tregs) in tumours are both known to be negative prognostic factors in cancer, and this study demonstrated a correlation between the two factors in canine neoplasia. Samples of 57 canine tumours and 29 canine lymph nodes categorized as tumour-draining, with or without metastasis, or reactive and not tumour-associated, were examined. Sequential sections were labelled by immunohistochemistry for glucose transporter 1 (Glut1) and FoxP3 as markers of hypoxia and Tregs, respectively. Up to 21 regions of interest (ROI) were selected in each section in a representative pattern and were assigned a semiquantitative score based on Glut1 labelling. The number of FoxP3(+) cells within each ROI was counted. A generalized estimating equation with negative binomial log link function was used to determine an association between Glut1 expression and FoxP3(+) cell count. Higher Glut1 immunoreactivity was correlated with significantly higher numbers of FoxP3(+) cells in the total tumour sample pool and total lymph node sample pool. Analysis of various subcategories of tumours and lymph nodes showed that this correlation was also present within samples characterized as malignant, haemopoietic mesenchymal tumours, non-haemopoietic mesenchymal tumours, epithelial tumours, lymphoma, lymph nodes containing metastases and reactive lymph nodes. These results indicate that hypoxia in canine tumours may result in an increased infiltration by Tregs.

Mental health, migration stressors and suicidal ideation among Latino immigrants in Spain and the United States.

BACKGROUND: Immigration stress appears to augment the risk for suicide behaviors for Latinos. Yet, specific risk factors that contribute to suicidal ideation (SI) among diverse Latino immigrant populations are not well established. METHODS: Data were collected in Boston, Madrid and Barcelona using a screening battery assessing mental health, substance abuse risk, trauma exposure, demographics, and sociocultural factors. Prevalence rates of lifetime and 30-day SI were compared across sites. Logistic regression modeling was used to identify sociodemographic, clinical, and sociocultural-contextual factors associated with 30-day SI. RESULTS: Five hundred and sixty-seven Latino patients from primary care, behavioral health and HIV clinics and community agencies participated. Rates of lifetime SI ranged from 29-35%; rates for 30-day SI were 21-23%. Rates of SI were not statistically different between sites. Factors associated with SI included exposure to discrimination, lower ethnic identity, elevated family conflict, and low sense of belonging (P<0.01). In the adjusted model, higher scores on depression, posttraumatic stress disorder, and trauma exposure were significantly associated with 30-day SI (OR=1.14, 1.04, and 7.76, respectively). Greater number of years living in the host country was significantly associated with increased odds of having SI (OR=2.22) while having citizenship status was associated with lower odds (OR=0.45). CONCLUSION: Latinos suffering depression, trauma exposure, and immigration stressors are more likely to experience SI. Despite differences in country of origin, education, and other demographic factors between countries, rates of SI did not differ. Recommendations for prevention and clinical practice for addressing suicidal ideation risk among Latino immigrants are discussed.

Remote synchronization in star networks.

We study phase synchronization in a network motif with a starlike structure in which the central node's (the hub's) frequency is strongly detuned against the other peripheral nodes. We find numerically and experimentally a regime of remote synchronization (RS), where the peripheral nodes form a phase synchronized cluster, while the hub remains free with its own dynamics and serves just as a transmitter for the other nodes. We explain the mechanism for this RS by the existence of a free amplitude and also show that systems with a fixed or constant amplitude, such as the classic Kuramoto phase oscillator, are not able to generate this phenomenon. Further, we derive an analytic expression which supports our explanation of the mechanism.

Recurrence-based detection of the hyperchaos-chaos transition in an electronic circuit.

Some complex measures based on recurrence plots give evidence about hyperchaos-chaos transitions in coupled nonlinear systems [E. G. Souza et al., "Using recurrences to characterize the hyperchaos-chaos transition," Phys. Rev. E 78, 066206 (2008)]. In this paper, these measures are combined with a significance test based on twin surrogates to identify such a transition in a fourth-order Lorenz-like system, which is able to pass from a hyperchaotic to a chaotic behavior for increasing values of a single parameter. A circuit analog of the mathematical model has been designed and implemented and the robustness of the recurrence-based method on experimental data has been tested. In both the numerical and experimental cases, the combination of the recurrence measures and the significance test allows to clearly identify the hyperchaos-chaos transition.

Prevalence of dementia and cognitive impairment in Southeastern Spain: the Ariadna study.

OBJECTIVES: To estimate the prevalence of amnestic mild cognitive impairment (aMCI), cognitive impairment, no dementia (CIND) and dementia in a general elderly population and to examine the associated socio-demographic factors. METHODS: The Ariadna study is a population-based cross-sectional study of cognitive function involving 1074 individuals aged 65-96 years from the Murcia Region of southeastern Spain. Prevalence, adjusted odds ratio (OR) and 95% confidence intervals (CI) were calculated. RESULTS: The overall prevalence was 8.7% (95% CI 7.1-10.5) for aMCI, 14.5% (95% CI 12.4-16.8) for CIND and 5.5% (95% CI 4.3-7.1) for dementia. Dementia was associated with age (OR 1.13 95% CI 1.09-1.18 for a 1-year increase in age). Illiterate subjects were more likely to present aMCI (OR 2.59; 95% CI 1.09-6.14) and dementia (OR 4.09; 95% CI 1.28-13.08) than subjects with secondary or higher education. Rural area residents (OR 2.13, 95% CI 1.07-4.24) and women (OR 1.53, 95% CI 1.06-2.22) were more likely to have CIND. CONCLUSION: The prevalence of dementia was low, despite a high prevalence of aMCI and CIND. Dementia was strongly associated with age and education. CIND was associated with living in a rural area and with female sex, while aMCI was associated with illiteracy.

Effects of mobility in a population of prisoner's dilemma players.

We address the problem of how the survival of cooperation in a social system depends on the motion of the individuals. Specifically, we study a model in which prisoner's dilemma players are allowed to move in a two-dimensional plane. Our results show that cooperation can survive in such a system provided that both the temptation to defect and the velocity at which agents move are not too high. Moreover, we show that when these conditions are fulfilled, the only asymptotic state of the system is that in which all players are cooperators. Our results might have implications for the design of cooperative strategies in motion coordination and other applications including wireless networks.

Magnetic resonance spectroscopy performance for detection of dementia, Alzheimer's disease and mild cognitive impairment in a community-based survey.

BACKGROUND/AIMS: To evaluate (1)H-labelled magnetic resonance spectroscopy (MRS) in patients with a low Mini Mental State Examination (MMSE) score identified during a dementia community-based survey. METHODS: A population sample of 1,500 individuals (>64 years old) was randomly selected. Two hundred and fifteen individuals (MMSE < or =24) were sorted into clinical groups: dementia, Alzheimer's disease, mild cognitive impairment (MCI), normal. Up to 56 of these individuals attended the MRS appointment. Two single-voxel sequences (TR 1,500, TE 35/144 ms) were carried out in the posterior cingulate gyrus of each individual, and the ratios N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/Cr, myo-inositol (mI)/Cr, NAA/mI and NAA/Cho were compared statistically. The ability of MRS to distinguish clinical groups was assessed by receiver-operating characteristics analysis. Cognition effects on metabolite ratios were estimated, with gender and cognition as categorical variables and age as a continuous covariate. RESULTS: NAA/Cr and NAA/Cho ratios were lower in dementia or Alzheimer's disease than in MCI and normal groups. The NAA/Cr ratio at TE 35 ms performed best when distinguishing dementia or Alzheimer's disease from non-demented subjects (cut-off point 1.40). MRS could not distinguish between MCI patients and normal subjects. Dementia was an independent predictor of metabolite values. CONCLUSION: In a population sample, conventional MRS still proved to be a useful tool for dementia discrimination, but it is potentially far less useful as a surrogate marker for MCI.

Recurrence analysis of strange nonchaotic dynamics in driven excitable systems.

Numerous studies have shown that strange nonchaotic attractors (SNAs) can be observed generally in quasiperiodically forced systems. These systems could be one- or high-dimensional maps, continuous-time systems, or experimental models. Recently introduced measures of complexity based on recurrence plots can detect the transitions from quasiperiodic to chaotic motion via SNAs in the previously cited systems. We study here the case of continuous-time systems and experimental models. In particular, we show the performance of the recurrence measures in detecting transitions to SNAs in quasiperiodically forced excitable systems and experimental time series.

A cellular nonlinear network: real-time technology for the analysis of microfluidic phenomena in blood vessels.

A new approach to the observation and analysis of dynamic structural and functional parameters in the microcirculation is described. The new non-invasive optical system is based on cellular nonlinear networks (CNNs), highly integrated analogue processor arrays whose processing elements, the cells, interact directly within a finite local neighbourhood. CNNs, thanks to their parallel processing feature and spatially distributed structure, are widely used to solve high-speed image processing and recognition problems and in the description and modelling of biological dynamics through the solution of time continuous partial differential equations (PDEs). They are therefore considered extremely suitable for spatial-temporal dynamic characterization of fluidic phenomena at micrometric to nanometric scales, such as blood flow in microvessels and its interaction with the cells of the vessel wall. A CNN universal machine (CNN-UM) structure was used to implement, via simulation and hardware (ACE16k), the algorithms to determine the functional capillarity density (FCD) and red blood cell velocity (RBCV) in capillaries obtained by intravital microscopy during in vivo experiments on hamsters. The system exploits the moving particles to distinguish the functional capillaries from the stationary background. This information is used to reconstruct a map and to calculate the velocity of the moving objects.

A programmable electronic circuit for modelling CO2 laser dynamics.

We introduce a programmable electronic circuit implementing the rich dynamics of CO2 laser models. The design and the implementation of the circuit are accomplished by using a programmable analog device, which permits an experimental characterization of the laser dynamics. The experimental results shown in the paper demonstrate that the circuit exhibits homoclinic chaos typical of CO2 laser with feedback modulation of cavity losses. Moreover, experimental results showing that noise regularizes the dynamical time scales of the system are reported.

A nonlinear circuit architecture for magnetoencephalographic signal analysis.

OBJECTIVES: The objective of this paper was to face the complex spatio-temporal dynamics shown by Magnetoencephalography (MEG) data by applying a nonlinear distributed approach for the Blind Sources Separation. The effort was to characterize and differ-entiate the phases of a yogic respiratory exercise used in the treatment of obsessive compulsive disorders. METHODS: The patient performed a precise respiratory protocol, at one breath per minute for 31 minutes, with 10 minutes resting phase before and after. The two steps of classical Independent Component Approach have been performed by using a Cellular Neural Network with two sets of templates. The choice of the couple of suitable templates has been carried out using genetic algorithm optimization techniques. RESULTS: Performing BSS with a nonlinear distributed approach, the outputs of the CNN have been compared to the ICA ones. In all the protocol phases, the main components founded with CNN have similar trends compared with that ones obtained with ICA. Moreover, using this distributed approach, a spatial location has been associated to each component. CONCLUSIONS: To underline the spatio-temporal and the nonlinearly of the neural process a distributed nonlinear architecture has been proposed. This strategy has been designed in order to overcome the hypothesis of linear combination among the sources signals, that is characteristic of the ICA approach, taking advantage of the spatial information.

Real time blood flow velocity monitoring in the microcirculation.

A real-time monitoring system based on the dual slit methodology for the characterization of the red blood cell velocity at the level of microcirculation has been developed. The analog photometric signals are acquired and processed using a hybrid hardware-software system that exploits a A/D conversion and an optimized correlation algorithm on an embedded system. It is implemented exploiting the resources of a general purpose board capable to extract the useful information from the noisy photometric signals, to process them, to show and save the results and, therefore, to make the experiments reproducible. Two different approaches to the crosscorrelation algorithm have been tested and their performances have been compared to each. The system has been tested in in vivo experiments on anaesthetized hamsters. Several microvessels have been observed and the results have been compared to the output of an analog crosscorrelator to verify their coherence.

Real-time estimation of oxygen concentration in micro-hemo-vessels.

In this paper, a real-time measurement system for non-invasive evaluation of oxygen concentration (PO2) at the microcirculation level is developed. The system has been designed by exploiting the phenomenon of fluorescence quenching. The skin of an anaesthetized hamster, injected with porphyrin, is lighted with pulses; the fluorophore reacts with the oxygen in the blood, producing a fluorescence signal, and the value of the fluorescence lifetime is related to the oxygen concentration. This microcirculation-based instrumentation consists of an electro-optical system, a control circuit and signal processing procedure. The system allows the measurement of PO2 in the range of 0-700 (mmHg) with a standard deviation of 4 (mmHg). Several experiments have been performed in order to characterize and test this system.

A comparison between HMLP and HRBF for attitude control.

In this paper the problem of controlling the attitude of a rigid body, such as a Spacecraft, in three-dimensional space is approached by introducing two new control strategies developed in hypercomplex algebra. The proposed approaches are based on two parallel controllers, both derived in quaternion algebra. The first is a feedback controller of the proportional derivative (PD) type, while the second is a feedforward controller, which is implemented either by means of a hypercomplex multilayer perceptron (HMLP) neural network or by means of a hypercomplex radial basis function (HRBF) neural network. Several simulations show the performance of the two approaches. The results are also compared with a classical PD controller and with an adaptive controller, showing the improvements obtained by using neural networks, especially when an external disturbance acts on the rigid body. In particular the HMLP network gave better results when considering trajectories not presented during the learning phase.

Chaotic behavior in noninteger-order cellular neural networks

In this paper, a simple system showing chaotic behavior is introduced. It is based on the well-known concept of cellular neural networks (CNNs), which have already given good results in generating complex dynamics. The peculiarity of the CNN model consists in the fact that it replaces the traditional first-order cell with a noninteger-order one. The introduction of the fractional cell, with a suitable choice of the coupling parameters, leads to the onset of chaos in a simple two-cell system. A theoretical approach, based on the harmonic balance theory, has been used to investigate the existence of chaos. A circuit realization of the proposed fractional two-cell chaotic CNN is reported and the corresponding strange attractor is also shown.

Multilayer Perceptrons to Approximate Quaternion Valued Functions.

In this paper a new type of multilayer feedforward neural network is introduced. Such a structure, called hypercomplex multilayer perceptron (HMLP), is developed in quaternion algebra and allows quaternionic input and output signals to be dealt with, requiring a lower number of neurons than the real MLP, thus providing a reduced computational complexity. The structure introduced represents a generalization of the multilayer perceptron in the complex space (CMLP) reported in the literature. The fundamental result reported in the paper is a new density theorem which makes HMLPs universal interpolators of quaternion valued continuous functions. Moreover the proof of the density theorem can be restricted in order to formulate a density theorem in the complex space. Due to the identity between the quaternion and the four-dimensional real space, such a structure is also useful to approximate multidimensional real valued functions with a lower number of real parameters, decreasing the probability of being trapped in local minima during the learning phase. A numerical example is also reported in order to show the efficiency of the proposed structure. Copyright 1997 Elsevier Science Ltd. All Rights Reserved.

Multi-layer neural network analysis of cerebrospinal fluid pressure patterns in idiopathic normal-pressure hydrocephalus.

The cerebrospinal fluid (CSF) pressure patterns have been reported as one of the most relevant indexes for the diagnosis and treatment of idiopathic normal-pressure hydrocephalus (INPH). Forty consecutive patients coming from our observations with the classic Hakim's triad underwent continuous CSF pressure monitoring via lumbar puncture for at least 12 hours. Twenty-eight patients were diagnosed as having INPH and underwent CSF shunt. A multi-layer neural network (perceptron) was employed to study the pressure patterns in order to try an alternative classification to the "expert" neurosurgeon one. Differences between expert and neural network classifications were indeed observed. Such differences may depend on the small group studied or on the inadequacy of CFS pressure patterns in correctly individuating those INPH patients who benefit from shunt surgery. The authors think that neural network processing of INPH could add relevant information to select the "responder" patients to surgery: in fact neural networks represent a powerful methodology for aiding the expert to select the proper choice on the basis of "what learnt" by the networks themselves.

Multilayer perceptrons to approximate complex valued functions.

In this paper the approximation capabilities of different structures of complex feedforward neural networks, reported in the literature, have been theoretically analyzed. In particular a new density theorem for Complex Multilayer Perceptrons with complex valued non-analytical sigmoidal activation functions has been proven. Such a result makes Multilayer Perceptrons with complex valued neurons universal interpolators of continuous complex valued functions. Moreover the approximation properties of superpositions of analytic activation functions have been investigated, proving that such combinations are not dense in the set of continuous complex valued functions. Several numerical examples have also been reported in order to show the advantages introduced by Complex Multilayer Perceptrons in terms of computational complexity with respect to the classical real MLP.