AIM:To elucidate the possible biological mechanism of silica-induced acute lung injury in rats.METHODS:Sixteen Male Sprague-Dawley rats were divided into control and acute silicosis model groups,and instilled intratracheally with 1 mL of normal saline and 50 g/L silica suspension,respectively.After 7 d,the rats were sacrificed for collection of lung tissue and serum.The serum levels of interleukin-1β(IL-1β),IL-18 and tumor necrosis factor-α(TNF-α)were measured by using ELISA.The protein expression levels of nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)and gasdermin D(GSDMD)were measured by immunohistochemistry.Bacterial DNA was ex-tracted from the lung tissue for 16S ribosomal RNA gene sequencing to characterize changes in the composition of lung flo-ra.The differences in the structure of bacterial flora between control and model groups were analyzed by bioinformatic analy-ses.RESULTS:Immunohistochemical analysis showed that the protein expression levels of NLRP3 and GSDMD were higher in the lungs of the rats in model group.In addition,serum cytokine profiling showed that IL-1β,IL-18 and TNF-α levels were significantly higher in model group.The most abundant bacterial genera in the lung flora of the rats in model group were Bifidobacterium,Clostridium sensu stricto 1,and Parasutterella.The NLRP3 and GSDMD levels in the lung tissue and IL-1β and TNF-α levels in serum were positively correlated with the abundance of Parasutterella.CONCLU-SION:The alterations in lung flora structure and increased inflammation levels may be the actual biological mechanisms underlying silica-induced acute lung injury.The modulation of lung flora may provide a basis for the prevention and treat-ment of silica-induced acute lung injury.

Objective To explore prenatal ultrasonic characteristics of fetal Currarino syndrome(CS)and methods for prenatal diagnosis of CS.Methods Two fetuses with CS confirmed by genetic examination were retrospectively analyzed,while 6 CS fetuses with complete prenatal ultrasonic data in literature were reviewed.Prenatal ultrasonic characteristics of CS fetuses and the method for prenatal diagnosis of CS were discussed.Results Among 8 CS fetuses diagnosed with prenatal ultrasound,4 were female singletons with a clear family history of CS,and MNX1 gene mutation was found in 1 fetus.The other 4 fetuses were 2 pairs of male monochorionic twins,all with MNX1 gene mutation.Among 8 CS fetuses,complete triad(sacral agenesis abnormalities,anorectal malformation and presacral mass)were displayed only in 2 fetuses,while all 8 had sacral agenesis abnormalities and 6(6/8,75.00％)were detected with prenatal ultrasound,6 had low location of conus medullaris and 2(2/6,33.33％)detected with prenatal ultrasound.Conclusion Prenatal ultrasound was the first choice for non-invasive diagnosis of fetal CS.When one of sacral agenesis abnormalities,anorectal malformation and presacral mass was found with prenatal ultrasound,the possibility of CS should be considered,and fetal MRI,genetic examination and prenatal genetic counselling should be recommended if necessary.

Objective To comprehensively compare the quality and filtration efficiency of medicinal maltose between two domestic manufacturers(B,C)and one foreign manufacturer(A),compare their product quality as an excipient for in-travenous immunoglobulin(IVIG),so as to determine the feasibility and substitutability of maltose as an excipient for IVIG from different manufacturers.Methods Quality inspection and comparison of maltose from different manufacturers,small-scale filtration tests,and product quality comparision of IVIG(pH4)were conducted.Results The comparis on results showed that there was no significant difference in the quality of medicinal maltose between manufacturer B and A,and there was no significant difference in the quality of IVIG(pH4)produced.The quality of manufacturer C did not meet the require-ments.Conclusion There is no significant difference in the quality of medicinal maltose produced by manufacturer B and A,which can be used for the production of IVIG(pH4).

Recessive dystrophic epidermolysis bullosa (RDEB) is caused by loss-of-function mutations in the COL7A1 gene encoding the α-1 chain of type Ⅶ collagen, leading to reduced or absent expression of basement membrane type Ⅶ collagen (C7) . Currently, there is no effective treatment for this rare disease, and the management is mainly palliative and supportive. Gene therapy is expected to be an effective treatment of RDEB. This review summarizes current strategies of gene therapy in clinical trials for RDEB, as well as their progress, pros and cons, and prospects.

Objective:To determine the direction of traction that has the least influence on temporomandibular joint (TMJ) during mandibular distraction osteogenesis(MDO).Methods:(1) The three-dimensional finite element model was established after the mandible data were obtained by cone beam computed tomography (CBCT) scanning, and the validity of the model was verified. (2) Based on the verified three-dimensional finite element model, the distraction osteogenesis of mandible was carried out with six different directions. (3) The effects of different traction directions on disc pressure, osteotomy displacement, temporal bone pressure and condylar pressure were measured.Results:(1)In the thinnest area of the articular disc, the direction of the minimum stress on the upper and lower surfaces of the disc was "along the direction of the mandible, parallel to the surface of the mandible" . (2) Under the same load, the displacement of each osteotomy surface along the traction direction was different, but the difference was not big, and the effect was basically the same. (3) "Along the direction of the mandible, parallel to the surface of the mandible" and "along the direction of the mandible and parallel to the sagittal plane" had less pressure on the temporal bone than other situations, and the two directions of traction were parallel to the mandible. After the force decomposition, the direction of the condyle was the smallest, so the pressure on the condyle was smaller.Conclusions:A satisfactory TMJ model can be obtained by DICOM. The traction force of "along the direction of the mandible body, parallel to the surface of the mandible body" and "along the direction of the mandible body and parallel to the sagittal plane" had the least effect on the TMJ. When designing the traction direction of MDO, we should not only consider the influence of surgery on the shape of jaw and upper respiratory tract, but also weigh in the influence of traction direction on the TMJ, and determine the direction of traction which has the least influence on the TMJ.

Objective:To determine the direction of traction that has the least influence on temporomandibular joint (TMJ) during mandibular distraction osteogenesis(MDO).Methods:(1) The three-dimensional finite element model was established after the mandible data were obtained by cone beam computed tomography (CBCT) scanning, and the validity of the model was verified. (2) Based on the verified three-dimensional finite element model, the distraction osteogenesis of mandible was carried out with six different directions. (3) The effects of different traction directions on disc pressure, osteotomy displacement, temporal bone pressure and condylar pressure were measured.Results:(1)In the thinnest area of the articular disc, the direction of the minimum stress on the upper and lower surfaces of the disc was "along the direction of the mandible, parallel to the surface of the mandible" . (2) Under the same load, the displacement of each osteotomy surface along the traction direction was different, but the difference was not big, and the effect was basically the same. (3) "Along the direction of the mandible, parallel to the surface of the mandible" and "along the direction of the mandible and parallel to the sagittal plane" had less pressure on the temporal bone than other situations, and the two directions of traction were parallel to the mandible. After the force decomposition, the direction of the condyle was the smallest, so the pressure on the condyle was smaller.Conclusions:A satisfactory TMJ model can be obtained by DICOM. The traction force of "along the direction of the mandible body, parallel to the surface of the mandible body" and "along the direction of the mandible body and parallel to the sagittal plane" had the least effect on the TMJ. When designing the traction direction of MDO, we should not only consider the influence of surgery on the shape of jaw and upper respiratory tract, but also weigh in the influence of traction direction on the TMJ, and determine the direction of traction which has the least influence on the TMJ.

Objective:To identify the risk factors for weaning failure after mandibular distraction osteogenesis in the infants with Pierre Robin sequence.Methods:A retrospective cohort study was conducted to collect clinical records of infants with Pierre Robin sequence underwent mandibular distraction osteogenesis at Guangzhou Women and Children′s Medical Center from November 2016 to May 2019.The inclusion criteria consisted of the following: age <1 yr and no serious cardiopulmonary disease or serious airway malformation.The medical charts were reviewed for sex, age, weight, premature delivery, low birth weight, preoperative intubation, preoperative pulmonary infection, ventilator-associated pneumonia, as well as mechanical ventilation time and distraction length at first weaning.The infants were divided into 2 groups according to the outcome of ventilator weaning at first attempt: successful group and failure group.The risk factors of which P values were less than 0.05 would enter the logistic regression analysis to stratify weaning failure-related risk factors. Results:A total of 140 infants were included in this study, of which 9 cases developed failure of weaning at first attempt after operation, with the incidence of 6.4%.The results of logistic regression analysis showed that the distraction length and incidence of ventilator-associated pneumonia were independent risk factors for weaning failure after operation ( P<0.05). Conclusion:The length of distraction and ventilator-associated pneumonia are independent risk factors for weaning failure after mandibular distraction osteogenesis in the infants with Pierre Robin sequence.

Objective:To analyze the characteristics of upper airway three-dimensional CT images in children with laryngoscope exposure.Methods:50 cases of Pierre Robin sequence who suffered mandibular distraction osteogenesis were included. Preoperation, Cone beam CT scan was performed to get upper airway anatomy information. Images were imported into medical engineering software Mimics for 3D reconstruction. The related anatomical parameters such as the cross-sectional area of the epiglottis tip, oral volume, palatopharynx volume, and glossopharyngeal volume were measured. The exposure of glottis was observed by direct laryngoscope after anaesthesia. According to Cormack-Lehane classification, 2 groups were divided into groups (group A, 30 cases), non exposure group (group B, 20 cases), and the difference of image data between the two groups was compared.Results:Comparing CT measurement index values of the two groups, it was found that there were no statistically significant differences in D4, D8, D10, D11, angle 3, angle 6 and oral volume between the two groups ( P≥0.05), while there were statistically significant differences in other indicators between the two groups ( P<0.05). The area of the airway at the tip of epiglottis and the volume of palatopharyngeal cavity are of great significance to the differential diagnosis of laryngoscopic exposure in children with Pierre Robin sequence, and the decision tree model was established accordingly. Conclusions:The decision tree model based on the area of the airway at the tip of epiglottis and the volume of the palatopharyngeal cavity can predict the difficulty of laryngoscopic exposure in children with Pierre Robin sequence.

Objective:To analyze the characteristics of upper airway three-dimensional CT images in children with laryngoscope exposure.Methods:50 cases of Pierre Robin sequence who suffered mandibular distraction osteogenesis were included. Preoperation, Cone beam CT scan was performed to get upper airway anatomy information. Images were imported into medical engineering software Mimics for 3D reconstruction. The related anatomical parameters such as the cross-sectional area of the epiglottis tip, oral volume, palatopharynx volume, and glossopharyngeal volume were measured. The exposure of glottis was observed by direct laryngoscope after anaesthesia. According to Cormack-Lehane classification, 2 groups were divided into groups (group A, 30 cases), non exposure group (group B, 20 cases), and the difference of image data between the two groups was compared.Results:Comparing CT measurement index values of the two groups, it was found that there were no statistically significant differences in D4, D8, D10, D11, angle 3, angle 6 and oral volume between the two groups ( P≥0.05), while there were statistically significant differences in other indicators between the two groups ( P<0.05). The area of the airway at the tip of epiglottis and the volume of palatopharyngeal cavity are of great significance to the differential diagnosis of laryngoscopic exposure in children with Pierre Robin sequence, and the decision tree model was established accordingly. Conclusions:The decision tree model based on the area of the airway at the tip of epiglottis and the volume of the palatopharyngeal cavity can predict the difficulty of laryngoscopic exposure in children with Pierre Robin sequence.

Objective To analyze the anatomical characteristics of the upper airway in Pierre Robin sequence pediatric patients with difficult laryngoscopy using the computed tomography-based three-dimensional reconstruction.Methods Fifty pediatric patients of both sexes with Pierre Robin sequence,aged 10-101 days,weighing 2.0-6.3 kg,of American Society of Anesthesiologists physical status Ⅲ,scheduled for elective mandibular distraction osteogenesis under general anesthesia,were enrolled in this study.Cone beam CT scan was performed to obtain upper airway anatomy information during the natural sleep before operation.Images were imported into medical engineering software MIMICS 17.0 to reconstruct the three-dimensional images of the oral and maxillofacial bones and airways.The related anatomical parameters were measured,including the distance between the alveolar ridge of the upper central incisor and root of the epiglottis (D1),distance between the root of the epiglottis and midpoint of glottis (D2),distance between the bilateral lower edge of the mandible and midpoint of glottis (D3),distance between the alveolar ridge of the lower central incisor and the lower edge of the mandible (D4),length of the mandibular ramus (D5),length of the mandible body (D6),and length of the total mandible (D7),angle between lines D1 and D2 (angle 1),the angle between line D2 and the alveolar ridge of the upper central incisor to the midpoint of glottis (angle 2),the angle between lines D3 and D4 (angle 3),the angle of the point of the upper central incisor alveolar ridge to the trailing edge of the hard palate and then to the root of epiglottis (angle 4),the angle of bilateral mandible (angle 5),the angle of the point of gnathion to the two gonions (angle 6),the airway cross-sectional area at the tip of epiglottis,volume of oral cavity,volume of velopharyngeal cavity,and volume of glossopharyngeal cavity.Fiberoptic bronchoscope-guided endotracheal intubation was performed under topical anesthesia with lidocaine.Propofol,sufentanil and cis-atracurium were intravenously injected to induce anesthesia after successful intubation,and then the pediatric patients were sent to the operating room.Anesthesia was maintained by inhalation of sevoflurane.The exposure of glottis was observed with a laryngoscope.Pediatric patients were divided into difficult laryngoscopy group (group A) and non-difficult laryngoscopy group (group B) according to whether they presented with difficult laryngoscopy (Cormack-Lehane classification Ⅲ or Ⅳ).Results Compared with group B,the airway cross-sectional area at the tip of epiglottis and in the volume of velopharyngeal cavity were decreased (P＜0.05),and no significant change was found in D1,D2,D3,D4,D5,D6,D7,angle 1,angle 2,angle 3,angle 4,angle 5,angle 6,volume of oral cavity or volume of glossopharyngeal cavity in group A (P＞0.05).Conclusion The three-dimensional CT images of the upper airway show characteristic changes in Pierre Robin sequence pediatric patients with difficult laryngoscopy,and the main manifestations are the decrease in the airway section area and in the volume of the palatopharyngeal cavity at the tip of the epiglottis.