As a new type of environmental pollutants, microplastics are widely distributed in the global ecosystem, and ingestion of microplastics may produce a number of toxic effects. Based on currently available publications, this paper describes the main pathways of exposure to microplastics, and summarizes the toxic mechanisms of microplastics in mammals, including oxidative stress, inflammatory response, immune damage, imbalance of gut microbiota, energy metabolism disorder and DNA damage, so as to provide insights into elucidation of the toxic mechanism mechanisms and health risk assessment of microplastics.

Objective To explore the effects of polystyrene microplastics(PS-MPs)on the growth,activity,oxida-tive stress levels,biofilm formation and virulence of Klebsiella pneumoniae.Methods Klebsiella pneumoniae was exposed to PS-MPs at different concentrations(10,50 and 100 μg/ml)and particle sizes(0.1,1.0 and 5.0 μm),and the growth curves were measured.The bacterial activity was determined by CCK-8(cell counting kit-8).The level of intracellular reactive oxygen species(ROS)was determined by fluorescence probe.The biofilm forming ability was determined by crystal violet staining.Real-time quantitative fluorescent PCR(qRT-PCR)was used to detect the relative expression levels of biofilm-forming genes(luxS,mrkA,wbbM,pgaA,wzm)and viru-lence genes(ureA,uge,wabG,fimH).Results A high concentration(100 μg/ml)of 0.1 μm PS-MPs had a stronger inhibitory effect on the growth and activity of Klebsiella pneumoniae,and the intracellular ROS level signifi-cantly increased,indicating that smaller particle size and higher concentration of PS-MPs were more toxic to bacte-ria.PS-MPs of 100 μg/ml particle size groups(0.1,1.0 and 5.0 μm)significantly promoted the biofilm forma-tion of Klebsiella pneumoniae.The relative expression levels of biofilm formation related genes(luxS,mrkA,wbbM,pgaA,wzm)and virulence genes(ureA,uge,wabG,fimH)increased.Conclusion By inducing Kleb-siella pneumoniae to produce a high level of ROS,PS-MPs can cause oxidative stress,inhibit the growth and activi-ty of bacteria,and enhance the biofilm formation ability and virulence,thus affecting the biological characteristics of Klebsiae pneumoniae.

A 54-year-old man was admitted to respiratory department with chief complaints of recurrent cough and dyspnea. Chest imaging showed multiple patchy shadows and interstitial changes. Evidence of infectious diseases was not definite, and antibiotic treatments were not effective. In the meantime, myelodysplasia syndrome was diagnosed with pancytopenia. The pathologic findings of transbronchoscopic lung biopsyshowed chronic inflammatory interstitial changes, suggesting a clinical diagnosis of organizing pneumonia. After glucocorticoids treatment, his condition aggravated. The second percutaneous lung biopsy showed the infiltration of a large number of neutrophils. Therefore, the final diagnosis of myelodysplasia syndrome with Sweet syndrome was made. Then glucocorticoids and supportive treatment were given This case may improve physicians' understanding of myelodysplasia syndrome complicated with Sweet syndrome.

This paper presents a systematic review of extant research investigating the effectiveness of Internet-based group cognitive behavioral therapy （IGCBT） for depression and anxiety symptoms with an emphasis on the treatment modalities， treatment protocols， efficacy and mechanism， together with a summary of research limitations and suggestions for future research. Cognitive behavioral therapy （CBT） is a structured， short-term and present-oriented psychotherapeutic treatment， its Internet- and group-delivered modalities have led to its wider application， and has proven to be clinically effective in alleviating depression and anxiety symptoms caused by different diseases， whereas some drawbacks have been reported. Thus this paper elaborates the clinical application， therapeutic effect and underlying mechanisms of IGCBT intervention for depression and anxiety symptoms， so as to provide references for its future application. ［Funded by the Natural Science Foundation of the Inner Mongolia Autonomous Region （number， 2019MS03038）