Objective To explore the high risk factors of different degrees of premature infants with bronchopulmonary dysplasia (BPD) and to provide theoretical basises for the clinical prevention of BPD.Methods The clinical datas of 64 cases patients with BPD who were diagnosed and hospitalized in Neonatology Department of Affiliated Hospital of Qingdao University from June in 2009 to March in 2016 were retrospective analyzed,from several aspects to analyze the BPD's high risk factors,such as the mother's factors,the perinatal factors,treatments after birth and complications.Results There were 27 moderate and mild cases,19 moderate cases and 18 severe cases in children who were diagnosed BPD;different degrees of BPD patients in gender,5 minute's apgar score,the repeated application of PS,long time of mechanical ventilation,high concentration of oxygen inhalation,neonatal pneumonia,blood transfusion and neonatal anemia's differences were significant in the severity of BPD difference (P =0.003,0.033,0.006,0.002,0.001,0.000,0.001,0.001,0.036,0.004).Conclusion Strengthen resuscitation in delivery room,shorten the mechanical ventilation time and reduce the high concentration oxygen inhalation,prevent and reduce the infection after delivery,reduce latrogenic blood loss and the number of blood transfusion are important measures to alleviate the severity of BPD.

OBJECTIVETo investigate the incidence of the second mesiobuccal canal (MB2) in the mesiobuccal root of the maxillary first and second molars in Chinese population using three techniques, including the clearing technique, spiral CT scanning and serial root sections.

METHODSA total of 216 extracted human first and 334 second maxillary molars were randomly divided into two groups respectively: group A and B. The teeth in group A were cleared. The specimens in group B were subjected to spiral CT scanning, and then the roots were cross-sectioned every 1 mm from the root apex. Under the Dental operating microscope (DOM), the incidence of MB2 were recorded.

RESULTS(1) The incidence of MB2 in the first and the second maxillary molars were 81.48% and 49.70% respectively by clearing, and 77.78% and 47.31% from S-CT scanning, 88.89% and 53.89% respectively from serial root section. The occurrence of MB2 in maxillary first molars was statistically higher than in maxillary second molars (P < 0.05, chi square test). (2) There was no significant difference among the three approaches for detecting the MB2 canal (P > 0.05, chi square test).

CONCLUSIONSBoth the maxillary first molars and the second molars have high incidence of MB2.

Dental Pulp Cavity ; anatomy & histology ; diagnostic imaging ; Humans ; In Vitro Techniques ; Molar ; anatomy & histology ; diagnostic imaging ; Radiography

OBJECTIVETo apply the functionally generated path (FGP) technique for modeling the occlusal surface of a computer-aided-design (CAD) posterior full crown to obtain anatomic morphology.

METHODSA patient with defected left mandibular first molar was employed. After tooth preparation and impression making, the gypsum working cast and die were scanned with a digitized mechanical scanner and the surface data was acquired. The interocclusal records at intercuspal position (ICP) and FGP were made in the patient's mouth. These records were placed on the working cast and their surfaces were scanned. In the process of the computer-aided designing full crown, the cusps and fossae of the occlusal surfaces were accurately modified according to the digitized information of ICP and FGP interocclusal records.

RESULTSA full crown was designed and the occlusal morphology of the restoration was adapted to dynamic occlusion as well as static occlusion.

CONCLUSIONSThe FGP technique was practical for the CAD of full crown and could avoid potential occlusal interferences with opposing teeth during function.

Adult ; Bite Force ; Computer-Aided Design ; Crowns ; Dental Occlusion ; Dental Prosthesis Design ; methods ; Humans ; Male

OBJECTIVETo compare the sealing ability and fracture resistance of roots endodontically treated with bonded and unbonded filling materials.

METHODSOne hundred and fifteen straight mandibular premolar teeth with single canal were divided randomly into 6 experimental groups, with 15 samples each, and 3 control groups. The sealing ability was evaluated using a glucose quantitative microleakage mode and fracture resistance was tested by universal testing machine.

RESULTSThe microleakage results showed that the bonded filling material had the lowest value while the unbonded filling material had the highest value in all groups. There were significant differences in microleakage value among the groups (P < 0.01), but no significant difference was noted in the fracture resistance among the testing groups (P = 0.7016).

CONCLUSIONSBonded filling material enhanced the sealing ability but could not reinforce the fracture resistance of endodontically treated teeth.

Humans ; Root Canal Filling Materials ; Root Canal Obturation

OBJECTIVETo evaluate the effects of bruxism on masticatory muscle electromyographic (EMG) activity.

METHODSTwenty-four bruxers and sixteen asymptomatic control subjects were included through questionnaire and clinical examination. EMG activity was recorded by placing surface electrodes on bilateral anterior temporalis (TA), masseters (MM), anterior digastrics (DA) and sternocleidomastoid (SCM) muscles. EMG activities at rest, during maximal voluntary clenching in intercuspal position and swallowing were recorded by means of Bio PAK system.

RESULTSEMG activities of TA and MM at rest were significantly higher in bruxism group than in control group (P<0.05). When subjects clenched their teeth in intercuspal position, the activities of TA and MM were much lower in bruxism group than in control one (P<0.05). EMG activity during swallowing was no significant difference between the two groups. The asymmetry index of bilateral TA and MM in bruxism group was a little higher than the control group, but there was no significant difference between the two groups (P>0.05).

CONCLUSIONMasticatory muscle dysfunction of bruxers is mainly represented as higher potential in postural position and lower potential during maximal voluntary clenching in intercuspal position of anterior temporalis and masseters.

Adult ; Bruxism ; Electromyography ; Female ; Humans ; Male ; Masseter Muscle ; Masticatory Muscles ; Muscle Contraction ; Temporal Muscle

OBJECTIVETo investigate the influence of a broad range of environmental conditions on initial rates of hydrogen peroxide produced by Streptococcus oralis (S. oralis).

METHODSFor each rate measurement, 1 ml aliquots of 10(12) cells/L mid-logarithmic phase S. oralis in TSBY were centrifuged and respectively washed by phosphate buffer containing 0.01-10 mmol/L glucose or sucrose, phosphate buffer with 5.0-7.5 pH or Bis-Tris buffer containing 0.01-100 mmol/L Ca(2+), 0.01-100 mmol/L F(-) or 0.01-100 mmol/L HFPO(3)(-). After S. oralis was cultured in respective buffer for 10, 20 and 30 min at 37 degrees C, the concentration of hydrogen peroxide in supernatant was assayed spectrophotometrically in 96-well micro-plate by ABTS-HRP at A(405).

RESULTSSynthesis rate of hydrogen peroxide by S. oralis was 7.48 micromol/L per minute without carbohydrate, the synthesis rate of hydrogen peroxide by S. oralis increased with 0.01-10 mmol/L glucose and 0.01-10 mmol/L sucrose, but there was no statistically significant difference in synthesis rate among the carbohydrate groups. The rates of H2O2 synthesis were inhibited in the buffer at pH 5.0-6.0, compared with pH 7.0 (P < 0.05). Ca(2+) had little influence on the rate of H2O2 synthesis. IC(50) of H2O2 synthesis rates by S. oralis responded to FHPO(3)(-) and F(-) were 12.65 mmol/L and 1.90 mmol/L respectively.

CONCLUSIONSEnvironmental conditions may influence the synthesis rate of H2O2 by S. oralis.

Culture Media ; chemistry ; Glucose ; Hydrogen Peroxide ; metabolism ; Hydrogen-Ion Concentration ; Metals, Heavy ; Streptococcus oralis ; metabolism

OBJECTIVETo investigate the effect of cytoskeleton reorganization inhibition with RNA interference on the activation of extracellular signal-regulated kinase (ERK1/2) in primary osteoblasts induced by fluid shear stress (FSS).

METHODSBALB/c mouse primary cultured osteoblasts were isolated by enzyme digestion technique. Osteoblasts were treated with LIM domain kinase 2 (LIM-2) specific siRNA or negative control siRNA, and then were loaded or unloaded by FSS of 1.2 Pa for 0, 5, 15, 30 and 60 min, respectively. The Western blotting was performed to detect the protein expression levels of P-ERK1/2 and ERK1/2, respectively. Two-way ANOVA and one-way ANOVA were used in data analysis.

RESULTSFSS loading for different time (0, 5, 15, 30, 60 min) treated with negative RNA inteference had significant effect on the levels of P-ERK/ERK ratio (0.047 ± 0.031, 0.253 ± 0.137, 0.390 ± 0.155, 0.613 ± 0.123, 0.680 ± 0.108, respectively, P < 0.01). Statistical analysis showed that there was significant interaction between FSS and cytoskeleton reorganization inhibition treated with RNA inteference on the levels of P-ERK/ERK ratio (P < 0.01). The levels of P-ERK/ERK ratio increased when osteoblasts were loaded for 5 - 15 min (0.623 ± 0.129 and 0.623 ± 0.064, respectively, P < 0.05) and returned to baseline at 30 min (0.333 ± 0.086), and then reached the peak at 60 min (0.667 ± 0.064, P < 0.01).

CONCLUSIONSFSS could activate ERK1/2 rapidly in primary cultured osteoblasts. Cytoskeleton reorganization inhibition treated with RNA interference speeded-up the activation of ERK1/2 by FSS, which could increase the sensitivity of ERK1/2 to FSS.

Animals ; Cells, Cultured ; Cytoskeleton ; metabolism ; physiology ; Lim Kinases ; genetics ; metabolism ; Mechanotransduction, Cellular ; Mice ; Mice, Inbred BALB C ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Osteoblasts ; cytology ; enzymology ; Phosphorylation ; RNA Interference ; RNA, Small Interfering ; Stress, Mechanical

Objective This study aimed to optimize the preparation condition of DNA-chitosan nanoparticles with high transfec-tion efficency through a central composition design .Methods The DNA-chitosan nanoparticles were prepared by complex coacervation between pEGFP and chitosan .We selected the concentrations of chitosan and plasmid as two experimental factors , and a central compos-ite design with two factors and five levels was used to optimize the preparation condition of DNA-chitosan nanoparticles for high transfec-tion efficency .The concentrations of chitosan and plasmid were selected as the independent variables , respectively .The dependent varia-bles included average particle size and transfection efficiency .The morphology of DNA-chitosan nanoparticles was observed using a trans-mission electron microscope .The size and zeta potential of nanoparticles were measured by dynamic light scattering ( DLS) and electro-phoretic light scattering ( ELS ) , respectively .The stability of plasmids in the process of nanoparticles preparation was investigated through the agrose gel electrophoresis .The expression of plasmids delivered by nanoparticles was observed under an inverted fluorescence microscope .The transfection efficiency of DNA-chitosan nanoparticles was assayed by flow cytometry .Results The preparation condition of DNA-chitosan nanoparticles with high transfection efficency was optimized successfully .Under the optimum preparative conditions , the DNA-chitosan nanoparticles were almost spherical .The average size of nanoparticles was 217.6nm, and distributed in a narrow range with a polydispersity index of 0.241.The zeta potential was +22.4 mV, which suggested that a den-sity of positive charge exist onto the surface of nanoparticles and consequently enhanced the stability of nanoparticles suspension .The results of gel electrophoresis showed that plasmids were not destroyed in the process of nanoparticles preparation .The cell transfection of nanoparticles was very highly efficient .The nanoparticles could effectively deliver the pEGFP plasmids into cells to express the green fluorescent protein at a high level.Conclusion The established mathematic models have the good predictive function .Under the optimum preparative condi-tions, the DNA-chitosan nanoparticles have the high potential of cell transfection .

At present, severe acute respiratory syndrome coronavirus-2(SARS-CoV-2)infection is still rampant worldwide.As of September 10, 2021, there were about 222 million confirmed cases of corona virus disease 2019(COVID-19)and more than 4.6 million deaths worldwide.With the development of COVID-19 vaccines and the gradual vaccination worldwide, the increasing number of cases in children and unvaccinated young people has drawn attention.According to World Health Organization surveillance data, the proportion of COVID-19 infection cases in children gradually increased, and the proportion of cases in the age groups of under 5 years and 5-14 years increased from 1.0% and 2.5% in January 2020 to 2.0% and 8.7% in July 2021, respectively.At present, billions of adults have been vaccinated with various COVID-19 vaccines worldwide, and their protective effects including reducing infection and transmission, reducing severe disease and hospitalization, and reducing death, as well as high safety have been confirmed.Canada, the United States, Europe and other countries have approved the emergency COVID-19 vaccination in children and adolescents aged 12 to 17 years, and China has also approved the phased vaccination of COVID-19 vaccination in children and adolescents aged 3 to 17 years. For smooth advancement and implementation of COVID-19 vaccination in children, academic institutions, including National Clinical Research Center for Respiratory Diseases, National Center for Children′s Health, and The Society of Pediatrics, Chinese Medical Association organized relevant experts to reach this consensus on COVID-19 vaccination in children.

Bronchopulmonary dysplasia(BPD)is a common chronic lung disease that occurs in preterm infants.The infant who with BPD has the feature of small gestational age, low birth weight and immature development of various organ systems.During hospitalization, it is easy to combine with brain injury in premature infant, metabolic bone disease of prematurity, retinopathy of prematurity and cholestasis syndrome, which seriously affect the survival rate and life quality of premature infants.This article reviewed the extrapulmonary complications of BPD in premature infants.