Identification of lung adenocarcinoma subtypes and a prognostic signature based on activity changes of the hallmark and immunologic gene sets.

Background: Lung adenocarcinoma (LUAD) has a complex tumor heterogeneity. Our research attempts to clearness LUAD subtypes and build a reliable prognostic signature according to the activity changes of the hallmark and immunologic gene sets. Methods: According to The Cancer Genome Atlas (TCGA) - LUAD dataset, changes in marker and immune gene activity were analyzed, followed by identification of prognosis-related differential gene sets (DGSs) and their related LUAD subtypes. Survival analysis, correlation with clinical characteristics, and immune microenvironment assessment for subtypes were performed. Moreover, the differentially expressed genes (DEGs) between different subtypes were identified, followed by the construction of a prognostic risk score (RS) model and nomogram model. The tumor mutation burden (TMB) and tumor immune dysfunction and exclusion (TIDE) of different risk groups were compared. Results: Two LUAD subtypes were determined according to the activity changes of the hallmark and immunologic gene sets. Cluster 2 had worse prognosis, more advanced tumor and clinical stages than cluster 1. Moreover, a prognostic RS signature was established using two LUAD subtype-related DEGs, which could stratify patients at different risk levels. Nomogram model incorporated RS and clinical stage exerted good prognostic performance in LUAD patients. A shorter survival time and higher TMB were observed in the high-risk patients. Conclusions: Our findings revealed that our constructed prognostic signature could exactly predict the survival status of LUAD cases, which was helpful in predicting the prognosis and guiding personalized therapeutic strategies for LUAD.

White Matter Microstructural Similarity and Diversity of Functional Constipation and Constipation-predominant Irritable Bowel Syndrome.

BACKGROUND/AIMS: The Rome III criteria separated chronic constipation into functional constipation (FC) and constipation-predominant irritable bowel syndrome (IBS-C), but some researchers questioned the partitioning and treated both as distinct parts of a continuum. The study aims to explore the similarity and diversity of brain white matter between FC and IBS-C. METHODS: The voxel-wise analysis of the diffusion parameters was used to quantify the white matter changes of female brains in 18 FC patients and 20 IBS-C patients compared with a comparison group with 19 healthy controls by tract-based spatial statistics. The correlations between diffusive parameters and clinical symptoms were evaluated using a Pearson's correlation. RESULTS: In comparison to healthy controls, FC patients showed a decrease of fractional anisotropy (FA) and an increase of radial diffusivity (RD) in multiple major fibers encompassing the corpus callosum (CC, P = 0.001 at peak), external capsule (P = 0.002 at peak), corona radiata (CR, P = 0.001 at peak), and superior longitudinal fasciculus (SLF, P = 0.002 at peak). In contrast, IBS-C patients showed FA and RD aberrations in the CC (P = 0.048 at peak). Moreover, the direct comparison between FC and IBS-C showed only RD differences in the CR and SLF. In addition, FA and RD in the CC were significantly associated with abdominal pain for all patients, whereas FA in CR (P = 0.016) and SLF (P = 0.040) were significantly associated with the length of time per attempt and incomplete evacuation separately for FC patients. CONCLUSION: These results may improve our understanding of the pathophysiological mechanisms underlying different types of constipation.

A Structure Design Method for Reduction of MRI Acoustic Noise.

The acoustic problem of the split gradient coil is one challenge in a Magnetic Resonance Imaging and Linear Accelerator (MRI-LINAC) system. In this paper, we aimed to develop a scheme to reduce the acoustic noise of the split gradient coil. First, a split gradient assembly with an asymmetric configuration was designed to avoid vibration in same resonant modes for the two assembly cylinders. Next, the outer ends of the split main magnet were constructed using horn structures, which can distribute the acoustic field away from patient region. Finally, a finite element method (FEM) was used to quantitatively evaluate the effectiveness of the above acoustic noise reduction scheme. Simulation results found that the noise could be maximally reduced by 6.9 dB and 5.6 dB inside and outside the central gap of the split MRI system, respectively, by increasing the length of one gradient assembly cylinder by 20 cm. The optimized horn length was observed to be 55 cm, which could reduce noise by up to 7.4 dB and 5.4 dB inside and outside the central gap, respectively. The proposed design could effectively reduce the acoustic noise without any influence on the application of other noise reduction methods.