Power Approximations for Meta-Analysis of Dependent Effect Sizes

Meta-analytic models for dependent effect sizes have grown increasingly sophisticated over the last few decades, which has created challenges for a priori power calculations. We introduce power approximations for tests of average effect sizes based upon the most common models for handling dependent effect sizes. In a Monte Carlo simulation, we show that the new power formulas can accurately approximate the true power of common meta-analytic models for dependent effect sizes. Lastly, we investigate the Type I error rate and power for several common models, finding that tests using robust variance estimation provide better Type I error calibration than tests with model-based variance estimation. We consider implications for practice with respect to selecting a working model and an inferential approach.

Morphology dependent effect of γ-Al2O3 for ethanol dehydration: nanorods and nanosheets

Boehmite (γ-AlOOH) nanorods and nanoplates were hydrothermally fabricated with the aid of tetrapropylammonium bromide by modifying the pH values of solutions. Under acidic conditions, the adsorption of anions like Br-...

Isolation of formononetin-7-O-β-D-glucopyranoside from the grass of Ononis arvensis L. and the assessment of its effect on induced platelet activation

Introduction. Analysis of the clinical and laboratory picture of the SARS-CoV-2 infection suggests the presence of microcirculation and oxygen transport disorders, hemolysis of erythrocytes, intra-alveolar fibrin formation and microthrombus formation in the patient’s pathogenesis. Accordingly, the search for potential anticoagulants, erythrocyte antiplatelet agents, membrane stabilizing drugs and mild thrombolytic drugs can prevent the development of life-threatening complications and reduce the mortality of COVID-19 patients.Aim. Isolation of formononetin-7-O-β-D-glucopyranoside from the grass of Ononis arvensis L. and identification of the molecular mechanisms of its effect on platelet activation in vitro, induced by TRAP-6 (Thrombin receptor activated peptide) and ADP (adenosine diphosphate).Materials and methods. Terrestrial parts of Ononis arvensis L. were collected in the SPCPU nursery of medicinal plants (Leningrad region, Vsevolozhsky district, Priozerskoe highway, 38 km). Isolation of formononetin-7-O-β-D-glucopyranoside was carried out by preparative high performance liquid chromatography on a Smartline device (Knauer, Germany) equipped with a spectrophotometric detector. The structure of formononetin-7-O-β-D-glucopyranoside was confirmed by one-dimensional and two-dimensional NMR spectroscopy (Bruker Avance III, 400 MHz, Germany), as well as high-resolution mass spectrometry (HR-ESI-MS) (Bruker Micromass Q-TOF, Germany). The study of the effect of formononetin- 7-O-β-D-glucopyranoside on induced platelet activation was carried out on human platelets isolated from the blood of healthy volunteers. To research the effect of formononetin-7-О-β-D-glucopyranoside on platelet aggregation flow cytofluorometry with Cyto-FLEX (Beckman-Coulter, USA) was used.Results and discussion. According to the method of fractionation and purification of the total extract of O. arvensis developed in previous studies, formononetin-7-O-β-D-glucopyranoside was isolated in an individual form for subsequent biological studies with a total yield of 30 % in comparison with its content in the original extract. In samples with formononetin-7-O-β-D-glucopyranoside and ADP, there is a pronounced inhibition of platelet activation – the percentage of active platelets ranges from 6.3–6.6 % at doses of formononetin-7-O-β-D-glucopyranoside 1 μM, 3 μM and 30 μM. The inhibitory effect of formononetin-7-O-β-D-glucopyranoside is not dose-dependent (p ≤ 0.05). In samples with formononetin-7-O-β-D-glucopyranoside and TRAP, there is also a pronounced inhibition of platelet activation. The percentage of active platelets is 8 % at 1 μM formononetin-7-O-β-D-glucopyranoside doses, 15 % at 3 μM doses, and 16 % at 30 μM doses.Conclusion. Administration of formononetin-7-O-β-D-glucopyranoside at doses of 1 μM, 3 μM, 30 μM strongly inhibits platelet activation induced by ADP and TRAP-6. For ADP, there is no dose-dependent effect, while for TRAP there is a weak dose-dependent effect, the greatest inhibition efficiency is achieved with the minimum investigated dose of 1 μM. In all cases, the results obtained are statistically significant.

Assessing the Effects of Vitamin D on Neural Network Function in Patients With Parkinson’s Disease by Measuring the Fraction Amplitude of Low-Frequency Fluctuation

Background: Recently, many studies have shown that low vitamin D (VD) levels may be related to an increased risk of Parkinson’s disease (PD), but the underlying mechanisms remain unclear.Objective: To explore the relationship between PD and VD levels, as well as to analyze the effects of VD on spontaneous brain activity and explore the possible mechanism of its involvement in PD risk.Methods: In a cross-sectional study, we quantified the difference in VD levels between 330 PD patients and 209 healthy controls (HC) to explore the correlation between VD and PD risk. We also acquired resting-state Functional Magnetic Resonance Imaging (rs-fMRI) data from 46 PD patients and 21 HC. The PD patients were divided into three groups according to 25(OH)D levels: PD patients with VD deficiency (PD + VDD), PD patients with VD insufficiency (PD + VDI), and PD patients with normal VD (PD + NVD). The effect of VD status on spontaneous neuronal activity in the whole brain was analyzed by measuring the fraction amplitude of low-frequency fluctuation (fALFF).Results: Compared with HC, the PD patients had lower serum 25(OH)D levels (23.60 ± 7.27 vs. 25.60 ± 5.78, P < 0.001). The 25(OH)D level may have a potential dose-dependent effect on the risk of PD (Ptrend = 0.007). A high risk of PD was associated with VD deficiency [25(OH)D < 20 ng/mL, OR = 2.319], and the lowest quartile of 25(OH)D concentration was associated with a high risk of PD (OR = 1.941). In the rs-fMRI study, PD + VDD patients had wider brain regions with altered fALFF than other PD groups when compared with the corresponding HC groups. Both PD + VDD and PD + VDI showed higher fALFF in the cuneus, left precuneus, calcarine cortex and right lingual, as well as lower fALFF in the left middle temporal gyrus. PD + VDD patients also showed higher fALFF in the left superior, middle and inferior frontal gyri, as well as the left precentral gyrus than HC. Among PD patients, there was only a statistically significant difference in fALFF between the PD + VDD and PD + NVD groups. Compared with the PD + NVD group, PD + VDD patients exhibited higher fALFF in the left precentral and left postcentral gyrus, as well as the left inferior parietal lobule.Conclusion: These results demonstrate that PD patients had lower serum VD levels than HC, and VD may have a potential dose-dependent effect on PD risk. Lower serum VD levels can affect the spontaneous neuronal activity of default-mode network (DMN) and visual pathway neurons in PD patients, providing a possible mechanism for its effect on PD risk.

Earthworm coelomocytes as a soil health assessment tool

Different pollutants can disrupt earthworm coelomocytes integrity and functions, and their responses can be applied as biomarkers of sublethal contaminant exposure. In this context, the aim of this study was to develop an in vitro protocol for coelomocyte extraction, maintenance and analysis with regard to soil health status and chemical toxicity profile assessments. The extrusion technique was first tested comparing previously depurated (purged stomach content) and non-depurated and resampled earthworms. After testing, earthworms were exposed to different 2,4D and chloroacetamide concentrations for methodology validation. The values of viability were not affected by food restriction since no statistical difference was observed between non-depurated (sample A) and depurated (sample B) organisms. Regarding to cell density, a significant (p<0;05) reduction of 22% was observed between non-depurated and depurated organisms, indicating that food restriction may affect cell density. However, the non-depurated resampling did not show a significant reduction, indicating that this assessment may not be affect by resampling of the same organism. For both chemical compounds, no change in cell viability was observed at all assessed concentrations and exposure times. However, for cell density, a mainly time-dependent effect was observed for organisms exposed to chloroacetamide, and concentration-dependent effect for organisms exposed to 2,4D. The proportion of immune system cells was altered, mainly after 24 h, with the increasing of granular amoebocytes proportion. The difference in the proportion of granular amoebocytes in earthworms exposed to 2,4D can be explained by the existence of recognition and elimination mechanisms for this chemical substance. Thus, assessments of pollutant responses with in vitro coelomocytes seem to be a powerful tool for ecotoxicological studies.

Age‐Dependent Effect of Ticagrelor Monotherapy Versus Ticagrelor With Aspirin on Major Bleeding and Cardiovascular Events: A Post Hoc Analysis of the TICO Randomized Trial

Background We aimed to evaluate the age‐dependent effect of ticagrelor monotherapy after 3‐month dual‐antiplatelet therapy (DAPT) versus ticagrelor‐based 12‐month DAPT on major bleeding and cardiovascular events in patients with acute coronary syndrome. Methods and Results From the TICO trial (Ticagrelor Monotherapy After 3 Months in the Patients Treated With New Generation Sirolimus‐eluting Stent for Acute Coronary Syndrome), which randomized 3056 patients (median age, 61 years) to the ticagrelor monotherapy after 3‐month DAPT group or ticagrelor‐based 12‐month DAPT group, this post hoc analysis evaluated the age‐dependent effect of the treatment strategies on the primary end point (a composite of major bleeding, death, myocardial infarction, stent thrombosis, stroke, or target‐vessel revascularization) using the subpopulation treatment effect pattern plot. The cutoff age for distinguishing patients with greater benefit from this strategy was also determined. The risk reduction effect of ticagrelor monotherapy after 3‐month DAPT versus ticagrelor‐based 12‐month DAPT on the primary end point gradually increased with age and was more marked from the subpopulation of age 64 years with the change point. With this cutoff value of 64 years, the occurrence of the primary end point was significantly lower in the ticagrelor monotherapy after 3‐month DAPT group than in the ticagrelor‐based 12‐month DAPT group (4.4% versus 9.0%; P =0.002) in patients aged ≥64 years (n=1278), but it was not different in those aged <64 years (n=1778) with a significant interaction ( P ‐interaction=0.036). Conclusions The age‐dependent increase in the benefit of ticagrelor monotherapy after 3‐month DAPT versus ticagrelor‐based 12‐month DAPT was observed in the patients with acute coronary syndrome. In elderly patients with acute coronary syndrome, ticagrelor monotherapy after short‐term DAPT might be more optimal than ticagrelor‐based 12‐month DAPT.