Effect of involuntary chronic physical exercise on beta-amyloid protein in experimental models of Alzheimer's disease: Systematic review and meta-analysis.

The excessive deposition of ß-amyloid proteins (Aß) is directly correlated with the establishment and development of Alzheimer's Disease (AD). Current treatments for AD only reduce symptoms instead of acting on Aß, the primary etiological agent. Hence, the anti-amyloid effect of regular exercise has been widely investigated as an alternative therapy. This systematic review and meta-analysis examined the anti-amyloid effect of regular physical exercise in animal models of AD. The search was conducted on the electronic databases Pubmed, Embase, Scopus and Web of Science without data limitation and using the following describers: "amyloid beta" (OR senile plaque OR amyloid plaque) and "exercise" (OR physical activity OR training). The risk of bias was evaluated using the SYRCLE's tool. Meta-analyses were conducted using models of random continuous effects. A total of 36 studies were selected and most used: transgenic mice (n = 29), treadmill training, duration of 12 weeks (interval of 4 to 28 weeks), rate of 60 min/day (interval of 30 min and up until free access) and speed of 12 m/min (interval of 3.2 to 32 m/min). The hippocampus and cortex were the most frequently investigated regions. Meta-analysis demonstrated a decrease in Aß with greater effect in unspecified isoforms Meta-analysis demonstrated a decrease in Aß with greater effect in unspecified isoforms (N = 4; SMD = -2.71, IC 95%: -3.59, -1.84, p < 0.00001, Q2 = 3.38, I2 = 11%) and Aß1-42 (N = 21; SMD = -1.94, IC 95%: -2.37, -1.51, p < 0.00001, Q2 = 33,37, I2 = 40%). Concerning training, greater effect was found with: 1) swimming (N = 4; SMD = -1.98, IC 95%: -3,28 - -0,68, p = 0.003, Q2 = 9.74, I2 = 69%), 2) moderate intensity (N = 4; SMD = -2.03, IC 95%: -3.31 - -0.75, p < 0.005, Q2 = 12.68, I2 = 76%); 3) duration up to six weeks (N = 6; N = 6; SMD = -2.35, IC 95%: -3.15 - -1.55, p < 0.00001, Q2 = 8.38, I2 = 40%); 4) young animals (SMD = -2.00, IC 95%: -2.59 - -1.42, p < 0.00001, Q2 = 24.90, I2 = 52%); 5) in the amygdala region (N = 1; SMD = -8.56, IC 95%: -12.88 - -4.23, p = 0.0001) and females (N = 4; SMD = -2.14, IC 95%: -3.48 - -0.79, p = 0.002, Q2 = 10.31, I2 = 71%). However, the reduction of Aß was associated with decrease of amyloidogenic pathway and increase of non-amyloidogenic. Hence, regular physical exercise demonstrated anti-amyloid effect in experimental models of AD through positive alterations in APP processing through different signaling pathways.

Neuroprotective mechanisms of chronic physical exercise via reduction of ß-amyloid protein in experimental models of Alzheimer's disease: A systematic review.

AIMS: Alzheimer's disease (AD) is the most common irreversible chronic neurodegenerative disease. It is characterized by the abnormal accumulation of ß-amyloid protein (Aß), which triggers homeostatic breakage in several physiological systems. However, the effect of chronic exercise on the formation of Aß as an alternative therapy has been investigated. This systematic review examines the antiamyloid effect of different types and intensities of exercise, seeking to elucidate its neuroprotective mechanisms. MAIN METHODS: The research was conducted in the electronic databases Pubmed, Embase, Scopus and Web of Science, using the following descriptors: "amyloid beta" (OR senile plaque OR amyloid plaque) and "exercise" (OR physical activity OR training). The risk of bias was evaluated through SYRCLE's Risk of Bias for experimental studies. KEY FINDINGS: 2268 articles were found, being 36 included in the study. A higher frequency of use of mice with genetic alterations was identified for the Alzheimer's disease (AD) model (n = 29). It was used as chronic training: treadmill running (n = 24), voluntary running wheel (n = 7), swimming (n = 4) and climbing (n = 2). The hippocampus and the cortex were the most investigated regions. However, physiological changes accompanied by the reduction of Aß and associated with AD progression were verified. It is concluded that exercise reduces the production of Aß in models of animals with AD. SIGNIFICANCE: Nevertheless, this effect contributes to the improvement of several physiological aspects related to Aß and that contribute to neurological impairment in AD.

Pool Boiling of Nanofluids on Biphilic Surfaces: An Experimental and Numerical Study.

This study addresses the combination of customized surface modification with the use of nanofluids, to infer on its potential to enhance pool-boiling heat transfer. Hydrophilic surfaces patterned with superhydrophobic regions were developed and used as surface interfaces with different nanofluids (water with gold, silver, aluminum and alumina nanoparticles), in order to evaluate the effect of the nature and concentration of the nanoparticles in bubble dynamics and consequently in heat transfer processes. The main qualitative and quantitative analysis was based on extensive post-processing of synchronized high-speed and thermographic images. To study the nucleation of a single bubble in pool boiling condition, a numerical model was also implemented. The results show an evident benefit of using biphilic patterns with well-established distances between the superhydrophobic regions. This can be observed in the resulting plot of the dissipated heat flux for a biphilic pattern with seven superhydrophobic spots, δ = 1/d and an imposed heat flux of 2132 w/m2. In this case, the dissipated heat flux is almost constant (except in the instant t* ≈ 0.9 when it reaches a peak of 2400 W/m2), whilst when using only a single superhydrophobic spot, where the heat flux dissipation reaches the maximum shortly after the detachment of the bubble, dropping continuously until a new necking phase starts. The biphilic patterns also allow a controlled bubble coalescence, which promotes fluid convection at the hydrophilic spacing between the superhydrophobic regions, which clearly contributes to cool down the surface. This effect is noticeable in the case of employing the Ag 1 wt% nanofluid, with an imposed heat flux of 2132 W/m2, where the coalescence of the drops promotes a surface cooling, identified by a temperature drop of 0.7 °C in the hydrophilic areas. Those areas have an average temperature of 101.8 °C, whilst the average temperature of the superhydrophobic spots at coalescence time is of 102.9 °C. For low concentrations as the ones used in this work, the effect of the nanofluids was observed to play a minor role. This can be observed on the slight discrepancy of the heat dissipation decay that occurred in the necking stage of the bubbles for nanofluids with the same kind of nanoparticles and different concentration. For the Au 0.1 wt% nanofluid, a heat dissipation decay of 350 W/m2 was reported, whilst for the Au 0.5 wt% nanofluid, the same decay was only of 280 W/m2. The results of the numerical model concerning velocity fields indicated a sudden acceleration at the bubble detachment, as can be qualitatively analyzed in the thermographic images obtained in this work. Additionally, the temperature fields of the analyzed region present the same tendency as the experimental results.

Fecal microbiota transplantation in the treatment of Clostridium difficile infection: state of the art and literature review.

Clostridium difficile infection is a common complication following intestinal dysbiosis caused by abusive antibiotic use. It presents medical importance due to the high rates of recurrence and morbidity. Fecal microbiota transplantation is an effective alternative for the treatment of recurrent and refractory C. difficile infection and consists of introducing the intestinal microbiota from a healthy donor into a patient with this infection. The exact physiological mechanism by which fecal microbiota transplantation alters the intestinal microbiota is not well established, but it is clear that it restores the diversity and structure of the microbiota by promoting increased resistance to colonization by C. difficile. Several routes of transplant administration are being studied and used according to the advantages presented. All forms of application had a high cure rate, and the colonoscopic route was the most used. No relevant complications and adverse events have been documented, and the cost-effectiveness over conventional treatment has proven advantageous. Despite its efficacy, it is not commonly used as initial therapy, and more studies are needed to establish this therapy as the first option in case of refractory and recurrent Clostridium difficileinfection.

Fecal microbiota transplantation in the treatment of Clostridium difficile infection: state of the art and literature review / Transplante de microbiota fecal no tratamento da infecção por Clostridium difficile: estado da arte e revisão de literatura

ABSTRACT Clostridium difficile infection is a common complication following intestinal dysbiosis caused by abusive antibiotic use. It presents medical importance due to the high rates of recurrence and morbidity. Fecal microbiota transplantation is an effective alternative for the treatment of recurrent and refractory C. difficile infection and consists of introducing the intestinal microbiota from a healthy donor into a patient with this infection. The exact physiological mechanism by which fecal microbiota transplantation alters the intestinal microbiota is not well established, but it is clear that it restores the diversity and structure of the microbiota by promoting increased resistance to colonization by C. difficile. Several routes of transplant administration are being studied and used according to the advantages presented. All forms of application had a high cure rate, and the colonoscopic route was the most used. No relevant complications and adverse events have been documented, and the cost-effectiveness over conventional treatment has proven advantageous. Despite its efficacy, it is not commonly used as initial therapy, and more studies are needed to establish this therapy as the first option in case of refractory and recurrent Clostridium difficileinfection.

RESUMO A infecção por Clostridium difficile é uma complicação comum após a disbiose intestinal ocasionada pelo uso abusivo de antibióticos. Apresenta elevada importância médica devido às altas taxas de recorrência e morbidade. O transplante de microbiota fecal é uma alternativa eficaz para o tratamento da infecção recorrente e refratária pelo C. difficile e consiste na introdução da microbiota intestinal de um doador saudável em um paciente portador desta infecção. O mecanismo fisiológico exato pelo qual o transplante de microbiota fecal altera a microbiota intestinal não está tão bem estabelecido, mas é evidente que restaura a diversidade e a estrutura da microbiota promovendo aumento da resistência à colonização pelo C.difficile. Diversas vias de administração do transplante estão sendo estudadas e utilizadas de acordo com as vantagens apresentadas. Todas as formas de aplicação apresentaram elevada taxa de cura, sendo a via colonoscópica a mais utilizada. Não foram documentados complicações e efeitos adversos relevantes, e seu custo benefício em relação ao tratamento convencional se mostrou vantajoso. Apesar da sua eficácia é pouco utilizado como terapia inicial, sendo necessários mais estudos para firmar essa terapêutica como primeira opção no caso de infecção por Clostridium difficile refratária e recorrente.

Timing of renal replacement therapy initiation by AKIN classification system.

INTRODUCTION: Previous studies using Acute Kidney Injury Network (AKIN)/RIFLE criteria to classify early initiation of renal replacement therapy (RRT) have defined it as the therapy started in less severe AKIN/RIFLE stages. Generally, these studies failed in demonstrating measurable benefits. METHODS: We compared RRT initiation in critically ill patients and defined early or late RRT in reference to timing after stage 3 AKIN was met: patients beginning RRT within 24 hours after acute kidney injury (AKI) stage 3 were considered early starters. AKIN criteria were evaluated by both urine output (UO) and serum creatinine (sCr) and patients with acute-on-chronic kidney disease were excluded. A propensity score methodology was used to control variables. RESULTS: A total of 358 critically ill patients were submitted to RRT. Only 150 patients with pure AKI at stage 3 were analyzed. Mortality was lower in the early RRT group (51.5 vs. 77.9%, P=0.001). After achieving balance between the groups using a propensity score, there was a significant 30.5 (95% confidence interval [CI] 14.4 to 45.2%, P=0.002) relative decrease of mortality in the early RRT group. Moreover, patients on the early RRT group had lower duration of mechanical ventilation, time on RRT and a trend to lower intensive care unit (ICU) length of stay. CONCLUSIONS: For the first time, AKIN was used with UO criterion to evaluate early and late RRT. Using a time-based approach could be a better parameter to access the association between RRT initiation and outcomes in patients with AKI.