Objective To analyze the distribution of image noise in low-dose chest CT scan and optimize the relative scanning parameters.Methods The CT images of the Chinese anthropomorphic chest phantom( CDP-1 C) were simulated into six groups of low-dose images with different noise indexs by using an image noise addition tool.The difference between the preset noise index and analog noise value was compared.The CT images of 20 volunteers were also simulated into nine groups of low dose scans with the tube currents of 10,30,50,80,100,120,150,180 and 240 mA.The noise values of images were recorded and analyzed.Results There was no statistical difference between the analog noise value and the noise index.The image noise of low-dose chest scan was increased with the decrease of tube current.The noise was increased quickly when the current was decreased from 50 to 30 mA ( F =24.09 - 40.79,P ＜ 0.05),but the noise increased slowly when the current decreased from 240 to 80 mA.There was no statistical difference between the noise of 80 mA group and that of 120 mA(P ＞ 0.05).Conclusions The noise addition tool can be used to evaluate the image noise of low-dose chest CT scan.Adoption of 80 mA in chest CT scan would result in low radiation dose without adding image noise.

Objective To summarize the clinical features of 22 probands diagnosed with congenital muscular dystrophy (CMD),and to provide genetic counseling and prenatal diagnosis for 23 fetuses of these pedigrees.Methods Data of 22 CMD patients who were treated in the Pediatric Department of Peking University First Hospital during October 2006 to March 2016 were analyzed.Informed written consents for participation in this study were obtained from the parents or guardians.Prenatal diagnosis was performed using DNA samples extracted from fetal villus cells of 12 cases at 11-13 gestational weeks and amniotic fluid of 11 cases at 18-22 gestational weeks.Direct DNA sequencing by polymerase chain reaction (PCR) and multiplex ligation-dependent probe amplification (MLPA) were used to detect CMD-related gene mutations.Linkage analysis of short tandem repeats (STRs) was used to identify maternal blood contamination and biological parents.Results Thirteen out of the 22 probands with CMD were diagnosed with congenital muscular dystrophy type 1 A (MDC1A),and all of them carried compound heterozygous mutations in LAMA2 gene.Prenatal diagnosis of 13 fetuses from these pedigrees found that four fetuses were wild-type,seven were heterozygotes and two carried the same mutations as their proband.Three probands with LMNA-related congenital muscular dystrophy (L-CMD) carried de novo mutations in LMNA gene.In these pedigrees,two fetuses were wild-type and one whose mother was mosaicism carried the same mutations as the proband.One proband with Ullrich congenital muscular dystrophy carried compound heterozygous mutations in COL6A2 gene and the fetus of the same pedigree was wild-type.Five probands were diagnosed with α-dystroglycanopathies.And among them,two cases of muscle-eye-brain disease (MEB) carried compound heterozygous mutations in POMGnT1 gene and the fetuses of the two peidgrees were heterozygotes;one case of congenital muscular dystrophy type 1C (MDC1C) had compound heterozygous mutations in FKRP gene and the fetus carried the same mutations;one patient diagnosed with POMGnT1-related congenital muscular dystrophy with mental retardation (CMD-MR) carried compound heterozygous mutations in POMGnT1 gene,and the fetus was positive for the same mutations;one proband with POMT1-related CMD-MR was positive for compound heterozygous mutations in POMT1 gene and the results of prenatal diagnosis for two fetuses of this pedigree showed that the first fetus had the same mutations as the proband,while the second was heterozygote.Conclusions No effective therapeutic method is available for CMD.Therefore,accurate genetic counseling and prenatal diagnosis are necessary to prevent CMD child from birth.

An effective therapeutic regimen for hepatic fibrosis requires a deep understanding of the pathogenesis mechanism. Hepatic fibrosis is characterized by activated hepatic stellate cells (aHSCs) with an excessive production of extracellular matrix. Although promoted activation of HSCs by M2 macrophages has been demonstrated, the molecular mechanism involved remains ambiguous. Herein, we propose that the vitamin D receptor (VDR) involved in macrophage polarization may regulate the communication between macrophages and HSCs by changing the functions of exosomes. We confirm that activating the VDR can inhibit the effect of M2 macrophages on HSC activation. The exosomes derived from M2 macrophages can promote HSC activation, while stimulating VDR alters the protein profiles and reverses their roles in M2 macrophage exosomes. Smooth muscle cell-associated protein 5 (SMAP-5) was found to be the key effector protein in promoting HSC activation by regulating autophagy flux. Building on these results, we show that a combined treatment of a VDR agonist and a macrophage-targeted exosomal secretion inhibitor achieves an excellent anti-hepatic fibrosis effect. In this study, we aim to elucidate the association between VDR and macrophages in HSC activation. The results contribute to our understanding of the pathogenesis mechanism of hepatic fibrosis, and provide potential therapeutic targets for its treatment.
Humans ; Hepatic Stellate Cells/pathology* ; Receptors, Calcitriol ; Liver Cirrhosis/pathology* ; Macrophages/metabolism*