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Meta-analysis of randomized controlled trials of the effects of probiotics on functional constipation in adults.
Zhang, C, Jiang, J, Tian, F, Zhao, J, Zhang, H, Zhai, Q, Chen, W
Clinical nutrition (Edinburgh, Scotland). 2020;(10):2960-2969
Abstract
BACKGROUND & AIMS Clinical trials have reported controversial results regarding the effectiveness of probiotics in alleviating functional constipation in adults. We reviewed relevant randomized controlled trials to elucidate the effectiveness of probiotics on constipation symptoms in adults with functional constipation. METHODS We searched Medline, the Cochrane Library, Web of Science, and Google Scholar for relevant articles published up to April 2019. The primary outcomes of interest were stool frequency, gut transit time (GTT), stool consistency, and bloating. Two authors independently performed the study selection, risk-of-bias assessment, and data extraction. The outcome data were extracted from each included study and synthesized using weighted mean differences (WMDs) or standardized mean differences (SMDs). Pooled data synthesis was performed using a random-effects model. RESULTS In total, 2327 relevant studies were identified, 15 of which were found to be eligible randomized controlled trials and were included in the meta-analysis. Pooling of the extracted data demonstrated that probiotic consumption significantly reduced the whole GTT by 13.75 h [95% confidence interval (CI): -21.93 to -5.56 h] and increased the stool frequency by 0.98 (95% CI: 0.36 to 1.60) bowel movements per week. This increase was significant with the consumption of multispecies probiotics [at least two bacteria; WMD: 1.22 (95% CI: 0.50 to 1.94) bowel movements per week] but not with the consumption of Bifidobacterium lactis [WMD: 1.34 (95% CI: -0.27 to 2.94) bowel movements per week] or B. longum [WMD: -0.02 (95% CI: -0.56 to 0.53) bowel movements per week] alone. Multispecies probiotics (WMD: 1.37; 95% CI: 0.72 to 2.01), but not single-species probiotics (WMD: 1.18; 95% CI: -0.59 to 2.96), improved stool consistency (WMD: 1.30; 95% CI: 0.22 to 2.38). Similarly, multispecies probiotics (at least two bacteria; WMD: -0.49; 95% CI: -0.85 to -0.13), but not single-species probiotics (WMD: -0.24; 95% CI: -0.55 to 0.07), significantly decreased bloating. Performance bias were high, whereas detection bias was unclear because of inadequate reporting. CONCLUSION Consumption of probiotics, in particular, multispecies probiotics, may substantially reduce the GTT, increase the stool frequency, and improve the stool consistency. Thus, probiotics can be regarded as safe and natural agents for alleviation of functional constipation in adults.
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Responses of soil enzymatic activities to transgenic Bacillus thuringiensis (Bt) crops - A global meta-analysis.
Li, Z, Cui, J, Mi, Z, Tian, D, Wang, J, Ma, Z, Wang, B, Chen, HYH, Niu, S
The Science of the total environment. 2019;(Pt 2):1830-1838
Abstract
Transgenic Bacillus thuringiensis (Bt) crops have been widely planted, and the resulting environmental risks have attracted extensive attention. To foresee the impacts of Bt crops on soil quality, it is essential to understand how Bt crops alter the soil enzymatic activities and what the important influencing factors are. We compiled data from 41 published papers that studied soil enzymatic activities with Bt crops and their non-Bt counterparts. The results showed that dehydrogenase and urease significantly increased, but neutral phosphatase significantly decreased under Bt crop cultivations without Bt residues incorporation. The activities of dehydrogenase, β-glucosidase, urease, nitrate reductase, alkaline phosphatase, and aryl sulfatase significantly increased under Bt crop cultivation with Bt residues incorporation. The response ratios of other enzymes were not significantly changed. Generally, the response ratios of soil enzymes were greater with Bt residues incorporation than those of Bt crop cultivations without Bt residues incorporation. Further, the response ratios of soil enzymes varied with Bt crop types and growth periods. It was the strongest under Bt cotton among Bt crops, and the significant responses usually appeared in the middle growth stages. The responses of soil enzymes ascribed more to the properties of Bt crops than to soil properties across sites. Given - significant responses of some soil enzymes to Bt crops, we recommended that soil environmental risks should be carefully evaluated over the transgenic crops.
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Meta-analysis of risk factors for amputation in diabetic foot infections.
Sen, P, Demirdal, T, Emir, B
Diabetes/metabolism research and reviews. 2019;(7):e3165
Abstract
BACKGROUND Knowledge of risk factors is crucial to develop management and treatment protocols for the prevention of lower extremity amputation for patients with diabetic foot infections (DFIs). METHODS We searched the research literature for studies reporting risk factors for lower extremity amputation in patients with DFI. The main outcome variables included both minor and major amputations. This study was reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, and the protocol was registered in PROSPERO (CRD42018118543). RESULTS A total of 2471 potential articles from the database search met the inclusion criteria. After reviewing the titles, abstracts, and full texts, remaining 25 articles were included in the final analysis. We identified 6132 patients with DFI in the 25 included articles. Of these, 1873 patients who underwent amputation were investigated. Male gender (odds ratio [OR]: 1.31), smoking (OR: 1.38), history of amputation (OR: 1.47), history of osteomyelitis (OR: 1.94), peripheral arterial disease (OR: 2.35), retinopathy (OR: 1.32), International Working Group on the Diabetic Foot (IWGDF) grades 3 and 4 (OR: 1.7 and 2.5), Wagner grades 4 and 5 (OR: 4.3 and 6.4), gangrene/necrosis (OR: 9.9), osteomyelitis (OR: 4.5), neuroischaemic DFI (OR: 3.06), severe infection (OR: 3.12), length of hospitalization (standardized mean difference [SMD]: 0.7), leukocytosis (OR: 1.76), mean erythrocyte sedimentation rate (ESR) (SMD: 0.5), mean C-reactive protein (CRP) (SMD: 0.8), tissue culture positivity (OR: 1.61), and isolation of Gram-negative bacteria from tissue culture (OR: 1.5) were found as predictors of amputation in DFI. CONCLUSIONS The present study highlighted some differences in diabetic foot ulcers and DFIs in terms of risk factors for lower extremity amputation. These data provide detailed information about risk factors for amputations among patients with DFI, thus contributing to the creation of new classification systems for assessment of high-risk patients.
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Responses of soil microbial communities to water stress: results from a meta-analysis.
Manzoni, S, Schimel, JP, Porporato, A
Ecology. 2012;(4):930-8
Abstract
Soil heterotrophic respiration and nutrient mineralization are strongly affected by environmental conditions, in particular by moisture fluctuations triggered by rainfall events. When soil moisture decreases, so does decomposers' activity, with microfauna generally undergoing stress sooner than bacteria and fungi. Despite differences in the responses of individual decomposer groups to moisture availability (e.g., bacteria are typically more sensitive than fungi to water stress), we show that responses of decomposers at the community level are different in soils and surface litter, but similar across biomes and climates. This results in a nearly constant soil-moisture threshold corresponding to the point when biological activity ceases, at a water potential of about -14 MPa in mineral soils and -36 MPa in surface litter. This threshold is shown to be comparable to the soil moisture value where solute diffusion becomes strongly inhibited in soil, while in litter it is dehydration rather than diffusion that likely limits biological activity around the stress point. Because of these intrinsic constraints and lack of adaptation to different hydro-climatic regimes, changes in rainfall patterns (primary drivers of the soil moisture balance) may have dramatic impacts on soil carbon and nutrient cycling.