Biology subjects

Gilani, N.

Publications and source records attributed to Gilani, N..

2 recordsLinked to original sources

bioRxiv2020

A Systematic Review and Meta-analysis for Association of Helicobacter pylori Colonization and Celiac Disease

Background and objectivesBased on some previous observational studies there is a theory that suggests a potential relationship between Helicobacter pylori (H. pylori) colonization and celiac disease (CD), however, the type of this relationship is still controversial. Therefore, we aimed to conduct a systematic review and meta-analysis to explore all related primary studies to find any possible association between CD and human H. pylori colonization. Data sourcesStudies were systematically searched and collected from four databases and different types of gray literature to cover all available evidence. After screening, the quality and risk of bias assessment of the selected articles were evaluated. Synthesis methodsMeta-analysis calculated pooled odds ratio (OR) on the extracted data. Furthermore, heterogeneity, sensitivity, subgroups, and publication bias analyses were assessed. ResultsTwenty-four studies were included in this systematic review, with a total of 5241 cases and 132947 control people. The results of meta-analysis on 24 studies showed a significant and negative association between H. pylori colonization and CD (pooled OR= 0.58; 95% CI = 0.45 - 0.76; P < 0.001), with no publication bias (P = 0.407). The LAbbe plots also showed a trend of having more H. pylori colonization in the control group. Among subgroups, ORs were notably different only when the data were stratified by continents or risk of bias; however, subgroup analysis could not determine the source of heterogeneity. ConclusionsAccording to the meta-analysis, H. pylori has a mild protective role toward CD. Although this negative association is not strong, it is statistically significant and should be further considered. Further investigations in both molecular and clinic fields with proper methodology and more detailed information are needed to discover more evidence and underlying mechanisms to clear the interactive aspects of H. pylori colonization in CD patients. Systematic review registration number (PROSPERO)CRD42020167730

microbiology↗

bioRxiv2019

Monte Carlo Simulation of Diffusion MRI in geometries constructed from two-photon microscopy of cortical gray matter

PurposeNeurodegenerative diseases such as Alzheimers disease cause changes and disruption to cortical microstructure and architecture. Diffusion MRI (dMRI) could potentially be sensitive to such changes. There is a growing interest in modeling of human cortical areas using a combination of quantitative MRI and 3D microscopy. The purpose of this study was to quantitatively characterize the cytoarchitecture of human cortical tissue from 3D fluorescence microscopy to simulate diffusion MRI (dMRI) signal in the cortex to better understand its diffusion signal characteristics.\n\nMethodsDiffusion of water molecules and dMRI signal were simulated by an indirect geometry based method and a direct voxel based method in microstructural details extracted from microscopy of cortex. Additionally, residence times of diffusing spins inside voxel volumes were considered to set effective resolution limits. Mean diffusivity (MD) and kurtosis (MK) were calculated for variable cell and neurite densities, sizes and diffusion times under realistic values for permeability and free diffusion.\n\nResultsBoth simulation methods could efficiently and accurately simulate dMRI signals with fractional anisotropy, diffusion coefficient and kurtosis in agreement with previous reports. Simulated MD and MK showed changes with increasing diffusion times specific to cortical cell density and sizes, with MK showing the highest sensitivity. Intra-voxel residence times with increasing diffusion times showed that the effective dMRI resolution approaches the thickness of cortical layers.\n\nConclusionsMonte Carlo simulations based on 3D microscopy data enable estimating changes in MD and MK over diffusion times and are sensitive to cortical cytoarchitecture and its possible changes in neurodegenerative disease. When considering layer-specific cortical dMRI, effective resolution due to residence times is an important concern.

biophysics↗