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Helicobacter pylori is a bacterium that infects approximately half of the world's population, being more prevalent in low‐ and middle‐income countries. H. pylori can cause gastritis, peptic ulcer disease, mucosa‐associated lymphoid tissue lymphoma, and gastric cancer, which is among the five most frequent cancers worldwide. Other factors such as a diet low in vegetables and high in processed red meat have been associated with gastric cancer. Here, we studied the effects of high altitude and diet on gastric disease severity in H. pylori infection in a multicenter cross‐sectional study in Peru (N = 343). We recruited people from villages with distinct eating habits (high meat consumption, mixed, and limited meat consumption diet) in the Andes (Puno), and compared them to people living at sea level with a mixed diet (Lima). H. pylori infection prevalence was higher at high altitude than at sea level. High altitude, diet, and age showed a significant correlation with the severity of gastric disease, whereas H. pylori infection and sex did not. However, high altitude was not found to be a risk factor for intestinal metaplasia, while diet and age were. At high altitude, a meat‐rich diet was associated with a higher incidence of metaplasia compared to a plant‐based diet. This study provides a comparison of communities living at high altitude with spontaneously different diets, showing that high processed red meat consumption is a risk factor for gastric disease. Further studies are needed to explain this phenomenon and its impact on the development and progression of gastric pathologies. [ABSTRACT FROM AUTHOR]

Effective testing is essential to control the coronavirus disease 2019 (COVID-19) transmission. Here we report a-proof-of-concept study on hyperspectral image analysis in the visible and near-infrared range for primary screening at the point-of-care of SARS-CoV-2. We apply spectral feature descriptors, partial least square-discriminant analysis, and artificial intelligence to extract information from optical diffuse reflectance measurements from 5 µL fluid samples at pixel, droplet, and patient levels. We discern preparations of engineered lentiviral particles pseudotyped with the spike protein of the SARS-CoV-2 from those with the G protein of the vesicular stomatitis virus in saline solution and artificial saliva. We report a quantitative analysis of 72 samples of nasopharyngeal exudate in a range of SARS-CoV-2 viral loads, and a descriptive study of another 32 fresh human saliva samples. Sensitivity for classification of exudates was 100% with peak specificity of 87.5% for discernment from PCR-negative but symptomatic cases. Proposed technology is reagent-free, fast, and scalable, and could substantially reduce the number of molecular tests currently required for COVID-19 mass screening strategies even in resource-limited settings. [ABSTRACT FROM AUTHOR]

Optical spectroscopic techniques have been commonly used to detect the presence of biofilm-forming pathogens (bacteria and fungi) in the agro-food industry. Recently, near-infrared (NIR) spectroscopy revealed that it is also possible to detect the presence of viruses in animal and vegetal tissues. Here we report a platform based on visible and NIR (VNIR) hyperspectral imaging for non-contact, reagent free detection and quantification of laboratory-engineered viral particles in fluid samples (liquid droplets and dry residue) using both partial least square-discriminant analysis and artificial feed-forward neural networks. The detection was successfully achieved in preparations of phosphate buffered solution and artificial saliva, with an equivalent pixel volume of 4 nL and lowest concentration of 800 TU· μ L−1. This method constitutes an innovative approach that could be potentially used at point of care for rapid mass screening of viral infectious diseases and monitoring of the SARS-CoV-2 pandemic. [ABSTRACT FROM AUTHOR]

Abstract: Electrical stimulation of excitable cells provides therapeutic benefits for a variety of medical conditions, including restoration of partial vision to those blinded via some types of retinal degeneration. To improve visual percepts elicited by the current technology, researchers are conducting acute electrophysiology experiments, mainly in cats. However, the rat can provide a model of a range of retinal diseases and possesses a sufficiently large eye to be used in this field. This article presents a long‐term anesthetic protocol to enable electrophysiology experiments to further the development of visual prostheses. Six Long‐Evans rats (aged between 14 and 16 weeks) were included in this study. Surgical anesthesia was maintained for more than 15 h by combining constant intravenous infusion of ketamine (24.0–34.5 mg/kg/h), xylazine (0.9–1.2 mg/kg/h), and inhaled isoflurane in oxygen (<0.5%). Overall heart rate, respiratory rate, and body temperature remained between 187–233 beats/min, 45–58 breaths/min, and 36–38 °C, respectively. Neural responses to 200‐ms light pulses were recorded from the superior colliculus using a 32‐channel neural probe at the beginning and before termination of the experiment. Robust responses were recorded from distinct functional types of retinal pathways. In addition, a platinum electrode was implanted in the retrobulbar space. The retina was electrically stimulated, and the activation threshold was determined to be 5.24 ± 0.24 μC/cm2. This protocol may be used not only in the field of visual prosthesis research, but in other research areas requiring longer term acute experiments. [ABSTRACT FROM AUTHOR]

The bypassing of degenerated photoreceptors using retinal neurostimulators is helping the blind to recover functional vision. Researchers are investigating new ways to improve visual percepts elicited by these means as the vision produced by these early devices remain rudimentary. However, several factors are hampering the progression of bionic technologies: the charge injection limits of metallic electrodes, the mechanical mismatch between excitable tissue and the stimulating elements, neural and electric crosstalk, the physical size of the implanted devices, and the inability to selectively activate different types of retinal neurons. Electrochemical and mechanical limitations are being addressed by the application of electromaterials such as conducting polymers, carbon nanotubes and nanocrystalline diamonds, among other biomaterials, to electrical neuromodulation. In addition, the use of synthetic hydrogels and cell-laden biomaterials is promising better interfaces, as it opens a door to establishing synaptic connections between the electrode material and the excitable cells. Finally, new electrostimulation approaches relying on the use of high-frequency stimulation and field overlapping techniques are being developed to better replicate the neural code of the retina. All these elements combined will bring bionic vision beyond its present state and into the realm of a viable, mainstream therapy for vision loss. [ABSTRACT FROM AUTHOR]

Previous contributions suggested that gastroesophageal reflux can be modeled in terms of a Poisson process. This study aims to provide empirical data to validate this statement in pediatric patients so that computational models can be broadly used as an alternative for research. A retrospective review of 63 pediatric patients who underwent 24-hour impedance- pH monitoring to discard gastroesophageal reflux disease was conducted in this study. Patients were grouped by age as preterm (21), infants (21), and children (21). All the tracings were analyzed by a trained physician who identified the reflux entry and the bolus clearance time of each episode. The time between reflux episodes was tested against three probability distributions (gamma, exponential and inverse Gaussian) whereas the bolus clearance time was tested against a normal probability distribution. Parameters were estimated using the maximum likelihood method. The Kolmogorov- Smirnov test and the Kullback- Leibler divergence were computed to evaluate the goodness of fit. One-way analysis of variance was applied to compare results along the three groups. Exponential fitting for inter-reflux time was successful in 90.48% of children older than 1 year. The overall reflux rate was 57.58 reflux episodes per day whereas the mean bolus clearance time ranged between 10.87 in preterm subjects and 12.05 in children, showing a good Gaussian fitting. The time between reflux episodes can be modeled in terms of a Poisson process in non tube-fed patients, whereas the bolus clearance time follows a normal distribution in all cases. [ABSTRACT FROM AUTHOR]

Gastroesophageal monitoring is limited to 96 hours by the current technology. This work presents a computational model to investigate symptom association in gastroesophageal reflux disease with larger data samples proving important deficiencies of the current methodology that must be taking into account in clinical evaluation. A computational model based on Monte Carlo analysis was implemented to simulate patients with known statistical characteristics Thus, sets of 2000 10-day-long recordings were simulated and analyzed using the symptom index ( SI), the symptom sensitivity index ( SSI), and the symptom association probability ( SAP). Afterwards, linear regression was applied to define the dependency of these indexes with the number of reflux, the number of symptoms, the duration of the monitoring, and the probability of association. All the indexes were biased estimators of symptom association and therefore they do not consider the effect of chance: when symptom and reflux were completely uncorrelated, the values of the indexes under study were greater than zero. On the other hand, longer recording reduced variability in the estimation of the SI and the SSI while increasing the value of the SAP. Furthermore, if the number of symptoms remains below one-tenth of the number of reflux episodes, it is not possible to achieve a positive value of the SSI. A limitation of this computational model is that it does not consider feeding and sleeping periods, differences between reflux episodes or causation. However, the conclusions are not affected by these limitations. These facts represent important limitations in symptom association analysis, and therefore, invasive treatments must not be considered based on the value of these indexes only until a new methodology provides a more reliable assessment. [ABSTRACT FROM AUTHOR]

Background The evaluation of symptom association in gastroesophageal reflux is an open problem. The scientific literature reports important deficiencies and clinicians are claiming a new methodology. This article provides an optimal method for the evaluation of symptom association, the binomial symptom index ( BSI). Methods A mathematical description of the BSI was presented for the study of association and causality. A total of n = 850 000 patients were simulated using a Monte Carlo model to perform a two-way sensitivity analysis. The average and the standard deviation of the BSI were evaluated in groups of 5000 patients with the same values of the reflux rate, symptom rate, association ratio, window of association, and monitoring time in order to contrast their influence on the estimator. Key Results The BSI decreased with the number of reflux episodes when there was association, and remained constant and below 40% when there was not. The standard deviation was no higher than 40% and decreased with the reflux or symptom rates, and more sharply with the monitoring time, reaching approximately 0% for 50 days. A window length matching the characteristic reflux-symptom lag maximized the overall BSI and minimized its dispersion. Twenty-four hour and 96-h monitorings allowed detecting association ratios of 50% and 25%, respectively. Conclusions & Inferences The BSI is a simple and reliable index for the evaluation of symptom association that considers all the parameters under analysis. Defining an appropriate cut-off value, the BSI can provide a measure of probability and strength of association simultaneously. [ABSTRACT FROM AUTHOR]

Bacterial internalization is an important process in the pathogenesis of infectious diseases in which nuclear factor kappaB (NF-κB) plays a prominent role. We present pharmacological evidence indicating that in bovine endothelial cells (BEC) the internalization of Staphylococcus aureus, a pathogenic bacterium that causes mastitis in bovine cattle, was associated with the activation of NF-κB. The internalization of S. aureus increased when BEC were stimulated with alpha-tumour necrosis factor (TNF-α) or beta-interleukin 1 (IL-1β) which are known activators of NF-κB. SN50 (an inhibitor peptide of NF-κB nuclear translocation) and BAY 11-7083 (a chemical that inhibits the IκBα phosphorylation) caused significant reduction in S. aureus intracellular number, indicating that its internalization was associated with the NF-κB activity. Furthermore, specific inhibition of c-Jun N-terminal kinase with SP600125 (SP) or p-38 with SB203580 (SB) did not cause any change in the S. aureus intracellular number compared with the untreated control. Finally, TNF-α treatment of BEC after the addition of both SP and SB, induced a significant increase in S. aureus internalization above the control value. These data indicate that NF-κB activity is associated with S. aureus internalization and suggest that this transcription factor may play a role in the pathophysiology of bovine mastitis caused by this bacterium. [ABSTRACT FROM AUTHOR]

Retinal electrostimulation is promising a successful therapy to restore functional vision. However, a narrow stimulating current range exists between retinal neuron excitation and inhibition which may lead to misperformance of visual prostheses. As the conveyance of representation of complex visual scenes may require neighbouring electrodes to be activated simultaneously, electric field summation may contribute to reach this inhibitory threshold. This study used three approaches to assess the implications of relatively high stimulating conditions in visual prostheses: (1) in vivo, using a suprachoroidal prosthesis implanted in a feline model, (2) in vitro through electrostimulation of murine retinal preparations, and (3) in silico by computing the response of a population of retinal ganglion cells. Inhibitory stimulating conditions led to diminished cortical activity in the cat. Stimulus-response relationships showed non-monotonic profiles to increasing stimulating current. This was observed in vitro and in silico as the combined response of groups of neurons (close to the stimulating electrode) being inhibited at certain stimulating amplitudes, whilst other groups (far from the stimulating electrode) being recruited. These findings may explain the halo-like phosphene shapes reported in clinical trials and suggest that simultaneous stimulation in retinal prostheses is limited by the inhibitory threshold of the retinal ganglion cells. [ABSTRACT FROM AUTHOR]