Objective To investigate the structural response of diaphragm and soleus of the rat after mechanical ventilation (MV), and to explore the specific mechanism of the dysfunction of both muscles.Methods Sixteen male Sprague-Dawley (SD) rats were randomly divided into control group and MV group, with 8 rats in each group. Rats in MV group were treated with controlled ventilation and maintained anesthesia, and those in control group were only anesthetized without MV and maintained anesthesia. The diaphragm and soleus were harvested after MV for 18 hours, and the morphology changes were observed with light microscope. The cross section of muscle fiber was observed by immunofluorescence technique analysis, and the cross-sectional area of muscle fiber was calculated. The ultra structural changes in muscle fibers were observed under transmission electron microscope.Results ① Observed under light microscope, the cross section of the diaphragm and soleus muscle in the control group was regular, the nucleus was normal and the cytoplasm was homogeneous. The fibers in the diaphragm-biopsy specimens from MV subjects were smaller than those from control subjects, whereas these signs were not found in soleus. But fiber atrophy in MV specimens was not accompanied by an inflammatory-cell infiltrate. ② Under the fluorescence microscope, the control group had a smaller cross-section of the slow-twitch muscle in diaphragm, while the fast-twitch muscle fibers werelarger. As compared with diaphragm-biopsy specimens from control, specimens from MV subjects showed decreased cross-sectional areas of slow-twitch and fast-twitch fibers, respectively (μm2: 1069.00±155.24 vs. 1297.12±331.15, 2279.66±442.31 vs. 3031.80±596.11, bothP < 0.05). The disproportionate decrease in fast-twitch fibers cross-sectional areas [(70.42±3.61)% vs. (75.63±2.48)%] resulted inan increase in the percentage of total area occupied by the slow-twitch fibers [(29.58±3.61)% vs. (24.35±2.48)%, bothP < 0.01]. There were no significant differences in cross-sectional areas of slow-twitch and fast-twitch fibers in soleus between control group and MV group (μm2: 3193.80±559.36 vs. 3008.84±559.22, 3392.86±514.56 vs. 3594.35±651.67, bothP > 0.05). ③ In the control group, the muscle fibers of the diaphragm and soleus were arranged orderly, the boundary of the light and dark bands and the Z-line were clear, and there was no autophagy in the visual field. The outer membrane of the mitochondria was complete, and the cristae were in the shape of clapboard. The signs of misalignment of myofibrils, disruption of Z-line and vacuolar mitochondria were found in diaphragm from MV group, whereas these signs were not found in soleus. Diaphragm from MV group exhibited an increase in autophagic vesicles visualized by transmission electron microscopy as compared with control group.Conclusions Controlled MV for 18 hours resulted in diaphragmatic inactivity and promoted muscle injury and atrophy, while autophagy and mitochondrial dysfunction were enhanced. Soleus immobilization for 18 hours was not associated with muscle atrophy. These facts suggest that the signaling associated with diaphragm atrophy during MV may involve different mechanisms compared with other models of muscle atrophy. Diaphragm appeared to be more susceptible to MV.

Objective To investigate the effect of calpeptin on diaphragmatic injury and atrophy under controlled mechanical ventilation in rats.Methods A total of 24 SPF Sprague-Dawley (SD) rats were randomly divided into anesthetized control group (CON group),24-hour controlled mechanical ventilation group (CMV group),and 24-hour CMV + treatment with calpeptin group (CMVC group),with 8 rats in each group.Animals in the CON group received an intraperitoneal injection of pentobarbital sodium without CMV and continuous infusion of pentobarbital sodium.A small-animal ventilator was used for 24 hours in rats of CMV group.Rats of CMVC were treated with a specific calpain inhibitor calpeptin (4 mg/kg).The drug was injected subcutaneously 2 hours before and 8,15 and 23 hours after mechanical ventilation.Changes in diaphragm ultrastructure,light microscopic picture,and myosin heavy chain (MHC) expression were observed.Results ① Alignment of myofilaments and normal Z-band,and the shape of mitochondria were maintained in CON group as revealed by electron microscope.The signs of misalignment of myofibrils,disruption of Z-band and vacuolar mitochondria were found in CMV group,and they were obviously improved in CMVC group.The density of muscle injury (× 10-2/μm2) in CMV group was significantly higher than that in control group (36.8 ± 13.7 vs.6.4 ± 6.3,t=6.373,P=0.001),and that in CMVC group was significantly lowered (17.6 ± 9.1 vs.36.8 ± 13.7,t=3.694,P=0.002).② In CON group,the diaphragm fibers appeared regular in cross section without pathologic change under light microscopy.Fuzzy muscle striations,irregular muscle fibers,centralized nuclei and swelling of capillary endothelial cells were observed in CMV group,while pathological changes in the CMVC group were milder significantly.③ In CMV group,the density of MHCslow and MHCfast was lower compared with that of CON group,and the gray value was lowered by 61.1％ (t=8.138,P=0.001) and 77.1％ (t=8.844,P=0.001),respectively,especially in MHCfast.However,the gray values of MHCslow and MHCfast were increased by 1.51 folds (t=4.601,P=0.010),and 1.33 folds (t=2.859,P=0.011),respectively,after treatment with calpeptin,and the elevation was more significantly in MHCslow.Conclusions Diaphragmatic injury and atrophy were found after CMV for 24 hour.Calpeptin could reverse the detrimental effects of CMV,and it suggested that calpain plays an important role in modulating the ventilator-induced dysfunction of the diaphragm.

OBJECTIVE: To explore the prenatal ultrasonographic features and genetic basis for an abortus suspected for type II Cornelia de Lange syndrome (CdLS2). METHODS: A fetus diagnosed with CdLS2 at the Shengjing Hospital Affiliated to China Medical University on September 3, 2019 was selected as the study subject. Clinical data of the fetus and family history was collected. Following induced labor, whole exome sequencing was carried out on the abortus. Candidate variant was verified by Sanger sequencing and bioinformatic analysis. RESULTS: Prenatal ultrasonography (33 weeks of pregnancy) has revealed multiple anomalies in the fetus, which included slightly widened cavity of septum pellucidum, blurred corpus callosum, slightly reduced frontal lobe volume, thin cortex, fusion of lateral ventricles, polyhydramnios, small stomach bubble, and digestive tract atresia. Whole exome sequencing has revealed a heterozygous c.2076delA (p.Lys692Asnfs*27) frameshifting variant in the SMC1A gene, which was found in neither parent and was rated as pathogenic based on the guidelines of American College of Medical Genetics and Genomics (ACMG). CONCLUSION The CdLS2 in this fetus may be attributed to the c.2076delA variant of the SMC1A gene. Above finding has provided a basis for genetic counseling and assessment of reproductive risk for this family.
Pregnancy ; Female ; Humans ; Cell Cycle Proteins/genetics* ; De Lange Syndrome/diagnosis* ; Phenotype ; Ultrasonography, Prenatal ; Fetus/diagnostic imaging* ; Mutation

【Objective:】 To explore the network characteristics of sleep quality and anxiety in first-line medical staff fighting against COVID-19, further understand the relationship between sleep quality and anxiety, and provide basis for intervention. 【Methods:】 Using the convenient sampling method, this paper used the Pittsburgh Sleep Quality Index (PSQI) and Self Rating Anxiety Scale (SAS) to conduct a questionnaire survey on the front-line medical staff who fought against the epidemic during the COVID-19. Network analysis was used to construct sleep quality and anxiety network, and R language was used for statistical analysis and visualization. 【Results:】 In the network of sleep quality and anxiety of first-line medical staff fighting against COVID-19, "sleep disorder" and "sleep quality", "unfortunate premonition" and "inability to sit still", "syncope" and "hand and foot tingling" were highly related. "Fatigue", "dizziness" and "panic" had the highest expected influence. "Sleep quality", "sleep disorder" and "fatigue" had the highest bridge expected influence. The average predictability value of all nodes was 0.778. 【Conclusion:】 This paper used network analysis to explore the sleep quality and anxiety of first-line medical staff fighting against COVID-19 and found that there was a unique correlation path between them. Intervention against core symptoms can ameliorate anxiety and sleep problems to the great extent, and provide guidance for improving the physical and mental health.