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Bisphenol A(BPA)as a typical environmental endocrine disruptor, has been widely used in daily consumer goods.It has reproductive, developmental, neurotoxicity and other biological toxicity, so it is gradually replaced by bisphenol F, bisphenol S, bisphenol AF and other analogues.Studies have shown that BPA and its analogues can enter the human body through many ways, have been detected in human blood, urine, placenta, breast milk, amniotic fluid and other tissue samples, and transmitted to the fetus, causing a variety of toxic effects, thus affecting the health of pregnant women and fetuses, and may lead to adverse pregnancy outcomes such as preterm delivery, abortion, low birth weight and so on.This article reviews the ways and current situation of exposure to BPA and its analogues during pregnancy in recent years, and its effects on maternal and fetal health, and puts forward reasonable suggestions for maternal and infant health from the point of view of exposure to adverse environmental factors, so as to provide inspiration for future research.
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Objective:To analyze the risk factors of pulmonary hemorrhage in very low and extremely low birth weight, and to provide reference for the treatment of pulmonary hemorrhage.Methods:The clinical data of very low and extremely low birth weight infants hospitalized in Qingdao Women and Children′s Hospital NICU from January 2017 to December 2021 were retrospectively analyzed.Eighty-six infants who were diagnosed with pulmonary hemorrhage were selected as the pulmonary hemorrhage group, and two hundred and two infants without pulmonary hemorrhage were selected as the control group.The differences of the survival rates, complications and parameters of platelet between the two groups were compared, and the risk factors of pulmonary hemorrhage by multivariate Logistic regression were analyzed.Results:The survival rate of pulmonary hemorrhage group and control group were 65.1%(56/86) and 90.1%(182/202), respectively.The survival rate of control group was significantly higher than that in the pulmonary hemorrhage group( χ2=26.241, P<0.01). There was no significant difference in fluid intake between the two groups within three days after birth( t=0.936, 1.811, 1.840, P=0.350, 0.073, 0.069). The multivariate Logistic regression analysis showed hemodynamically significant patent ductus arteriosus( OR=2.304, 95% CI: 0.213~1.564, P=0.010), disseminated intravascular coagulation( OR=3.143, 95% CI: 0.061~2.521, P=0.028), thrombocytopenia( OR=0.991, 95% CI: -0.015~-0.005, P=0.001) and low mean platelet volume( OR=0.337, 95% CI: -1.657~-0.739, P=0.001) were the risk factors of pulmonary hemorrhage. Conclusion:Hemodynamically significant patent ductus arteriosus, disseminated intravascular coagulation, thrombocytopenia and low mean platelet volume were associated with increased risks for pulmonary hemorrhage in very low and extremely low birth weight.These risk factors should be actively monitored and treated, which is helpful to early identify and prevent pulmonary hemorrhage.
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Bronchopulmonary dysplasia(BPD)is a common chronic lung disease in preterm infants, which seriously affects the survival rate of preterm infants.Its etiology and pathogenesis are complex and unclear.Therefore, the prevention, diagnosis and treatment of BPD have become an important clinical issue.With the rapid development of high-throughput sequencing technology, it has been found that the respiratory tract flora can act as an early biomarker of BPD risk, and then judge the progress of BPD and the timing of treatment, so as to achieve the purpose of early treatment and improved prognosis.This article mainly describes the changes in the diversity and abundance of the respiratory tract flora of BPD in premature infants, the mechanism of action of the flora on BPD, and the future treatment methods based on the flora.
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Objective:To investigate the effects of different phototherapy intensities on the levels of malondialdehyde, a peroxidation product of intralipid, vitamin C and vitamin E in parenteral nutrition for premature infants.Methods:The parenteral nutrition for premature infants was prepared under strict aseptic condition and was divided into four groups based on different phototherapy intensities in simulated clinical settings, which were indoor light group, single-, double-, and three-sided phototherapy group. According to whether the nutrient solution shielded for light or not, each group was further divided into two subgroups: exposure or non-exposure group. The levels of malondialdehyde, vitamin C and vitamin E in all groups before phototherapy and 6, 12, 18, and 24 h after phototherapy were measured. Ten samples of parenteral nutrient solutions were prepared for each group, of which 2 ml were extracted for test at different time points. Repeated measurement analysis of variance was used for data analysis and the results were adjusted using Greenhouse-Geisser method if failed in Mauchly sphere test.Results:With the increase of phototherapy time, the malondialdehyde level increased in the exposure and the non-exposure subgroups in the one-sided phototherapy group [before phototherapy: (3.777±0.112) vs (3.746±0.141) nmol/ml; phototherapy for 6 h: (3.808±0.122) vs (3.715±0.145) nmol/ml; 12 h: (4.546±0.138) vs (4.507±0.136) nmol/ml; 18 h: (6.116±0.151) vs (5.239±0.156) nmol/ml; 24 h: (7.569±0.136) vs (5.300±0.200) nmol/ml; all P<0.05], but the level of vitamin C [before phototherapy: (62.507±0.205) vs (62.341±0.144)μg/ml; phototherapy for 6 h: (51.211±0.086) vs (58.128±0.076) μg/ml; 12 h: (43.288±0.084) vs (55.351±0.050) μg/ml; 18 h: (35.758±0.113) vs (51.215±0.093) μg/ml; 24 h: (33.473±0.075) vs (48.473±0.080)μg/ml] and vitamin E decreased [before phototherapy: (4.101±0.132) vs (4.084±0.141) μg/ml; phototherapy for 6 h: (3.761±0.119) vs (3.904±0.075) μg/ml; 12 h: (3.654±0.092) vs (3.729±0.087) μg/ml; 18 h: (3.385±0.102) vs (3.582±0.119) μg/ml; 24 h: (3.313±0.127) vs (3.438±0.113) μg/ml, all P<0.05]. The same situation was also observed in indoor light group, double-, and three-sided phototherapy groups. The malondialdehyde level at different time in the exposure subgroups were higher but the vitamin C and vitamin E levels were lower than those in the non-exposure subgroups, regardless of the phototherapy intensities (all P<0.001). (2) The analysis of all exposure phototherapy subgroups showed that the higher the intensity of light therapy, the higher the malondialdehyde level, and the lower the level of vitamin C and vitamin E, with statistical significance differences in any pairwise comparison. Analysis of all non-exposure subgroups showed statistically significant differences in the malondialdehyde level in any pairwise comparison (all P<0.05) except for the comparison between indoor light group and single-sided phototherapy group ( F=2.383. P=0.140). Moreover, the greater the phototherapy intensities, the lower vitamin C level, with statistically significant differences in any pairwise comparison. And statistical significance differences were observed in the vitamin E level in any pairwise comparison (all P<0.05) except for the comparison between double- and three-sided phototherapy groups ( F=1.358, P=0.259). Conclusions:Phototherapy can increase the malondialdehyde level in parenteral nutrient solution for premature infants and the degree of intralipid peroxidation, but can also lead to vitamin C and vitamin E loss in the parenteral nutrient and weaken its antioxidant capacity.
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Objective:To explore the clinical characteristics, treatment and prognosis of neonatal septicemia caused by Streptococcus agalactiae.Methods:There were 29 cases of neonatal septicemia caused by Streptococcus agalactiae from January 2017 to December 2019 treated at Qingdao Women and Children′s Hospital.These cases were divided into the early-onset group (onset day of the patients ≤7 d) and late-onset group (onset day of the patients>7 d). Clinical data were collected for analysis.Results:The cases included in the current study accounted for 10.8% of all neonatal septicaemia during the same period.There were 23 cases born via vaginal delivery (79.3%) and 6 cases born by cesarean section (20.7%). Eighteen cases (62.1%) had early-onset (≤7 d) sepsis, and eleven cases (37.9%) had late-onset (>7 d) sepsis.The incidence of pneumonia was higher in the early-onset group compared with the late-onset group (83.3% vs.36.4%), while the incidence of purulent meningitis in early-onset group was lower than that in the late-onset group (33.3% vs.81.8%), and the length of hospital stay was shorter in early-onset group[(16.17±9.33)d vs.(36.73±27.43)d]. The differences between two groups were statistically significant (all P<0.05). Peripheral white blood cell counts elevated in 9 (31.0%) cases, and reduced in 15 (51.7%) cases.The levels of C-reactive protein increased in 18 (62.1%) cases, while the early value of procalcitonin increased in all cases.Drug sensitivity test showed that the sensitivity rates to erythromycin, clindamycin and tetracycline were 30.0%, 31.0%, and 24.1%, respectively.All strains were sensitive to penicillin G, ampicillin, vancomycin, linezolid and cefotaxime.A total of 28 cases were treated with two antibiotics.Twenty-two cases (75.9%) were cured, three cases (10.3%) were discharged after improvement, four cases (13.8%) died after abandoning treatment, and one case was left with neurological sequelae. Conclusion:Streptococcus agalactiae is one of the common pathogens of neonatal septicemia.Children with different onset time may have different complications.Decrease in white blood cell counts and elevation of procalcitonin are highly sensitive to neonatal septicaemia caused by Streptococcus agalactiae.Penicillin and/or cephalosporin antibiotics are the first choice in treatment, and the critically ill patients are treated with combination of two antibiotics.
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Objective To determine the clinical value of contrast enhanced MRI in differentiating benign and malignant pancreatic endocrine tumors (PNETs).Methods MRI findings on 13 cases who were pathologically diagnosed as PNETs were retrospectively analyzed , including the tumor volume , border , MRI signal and adjacent organ involvement of Grade 1~3 tumors, and the sensitivity, specificity and accuracy of MRI for diagnosing PNETs were calculated .Results A total of 18 tumors were detected , including 12 benign (Grade 1) and 6 malignant (Grade 2~3) tumors.Eight Grade 1 tumors′(66.7%) maximal diameters were≤2 cm, while 100%(6 /6) Grade 2 ~3 tumors′maximal diameters were ≥2 cm.All of Grade 1 tumors (100%) had clear boundary , while 50%(2/4) Grade 2 and 100%(2/2) Grade 3 tumors had unclear boundary.Ten Grade 1 tumors (83.3%) had intratumoral homogeneous signal , while 100%(6/6) Grade 2~3 tumors had heterogeneous intratumoral signal .Two Grade 3tumors ( 100%) had organ infiltration and retroperitoneal lymph node metastasis .The sensitivity ,specificity and accuracy of MRI for differentiating benign and malignant PNETs were 833.%, 85.7%and 84.6%, respectively.Conclusi ons MRI had higher sensitivity, specificity and accuracy in differentiating benign and malignant PNETs , but it was still difficult to differentiate Grade 1 from Grade 2 tumors by MRI.Tumors size could not be considered to be a reliable indicator for differentiating benign and malignant PNETs .
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Objective To investigate the effect of all-trans retinoic acid (at-RA) on fetal alveolar epithelial type Ⅱ cells (fAEC Ⅱ s) proliferation and the expression of pulmonary surfactant C (SPC) as well as aquaporin 5 (AQP5).Methods fAEC Ⅱ s were isolated and purified from fetal lung of pregnant SD rats (19 days).After being cultured for 1 day,and the fAEC Ⅱ s were interfered by at-RA for 1,2 and 3 days.Cell proliferation,viability as well as growth state,expressions of SPC mRNA as well as AQP5 mRNA and expressions of protein SPC as well as AQP5 were respectively detected by using 4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT),inverted microscope,real-time fluorescence quantitative PCR (RT-PCR) and Western blot.Results (1) When fAEC Ⅱ s were treated with at-RA for 1 day,and the cell proliferation and viability did not change (P ＞ 0.05),while the proliferation and viability were significantly improved in 2 days (P ＜ 0.05),and the difference was the most obvious (P ＜ 0.05) at 3 days.(2)Compared with the control group,the cell growth state was better,and the cell adherence was tighter and the refraction was higher in at-RA group.(3) Compared with the control group,at-RA up-regulated the expressions of AQP5 mRNA and AQP5 protein(t =-19.58,-10.44,-16.01,-46.25,-12.79,-27.96,all P ＜ 0.05),and the percentages of control group were 281.07％,766.67％,1 163.33％ and 792.65％,1 310.52％,1 561.56％ in 1,2 and 3 days respectively.(4) Compared with control group,the expressions of SP-C mRNA and SPC protein were up regulated when cells were exposed to at-RA for 1 and 3 d,but while they were down-regulated at 2 days(protein:the percentages of control group were 615.480％,369.450％ and 11.269％,respectively ; mRNA:728.33 ％,400.83 ％,66.57％,respectively)(t=-26.34,-25.26,13.80,-25.25,-31.71,9.12,all P＜0.05).Conclusions at-RA can promote the proliferation and differentiation of fAEC Ⅱs,enhance the fAEC Ⅱ s viability,and improve the expression of SPC and AQP5.
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Objective To study the effects of the Notch ligands Dlk1 and recombinant human nucleu factorκB (Jagged1) on the proliferation and transdifferentiation of the type Ⅱ alveolar epithelial cells when the Notch signaling pathway activated.Methods The primary type Ⅱ alveolar epithelial cells (AEC Ⅱ) cultured with recombinant protein Dlk1 and recombinant human nucleu factor-κB (rhNF-κB) (activator of Jagged1),respectively,and then cultured with DMEM (containing 120 mL/L FBS) as controls.Proliferation and differentiation conditions of the AEC Ⅱ were observed at 48 h,72 h,96 h time point by the light microscope and electron microscopes separately.Cell number was counted with hemacytometer; the proliferation rate was measured by methyl thiazolyl tetrazolium (MTT) ; Immunofluorescence double standard method was used to detect the AEC Ⅱ specific surfactant protein C (SP-C) and AEC Ⅰ specific protein aquaporin5 (AQPS) ;the expression of SP-C,AQPS,Dlk1,Jagged1,Notch1 and Hes1 mRNA were detected by real time-PCR.Results The cell population and proliferation:compared with control group,AEC Ⅱ proliferation was promoted in the Dlk1 group [cell numbers (× 109/L) 9.05 ± 0.45 vs 7.95 ± 0.65,11.68 ± 0.43 vs 8.68 ± 0.52,11.55 ± 0.17 vs 8.73 ± 0.48,all P ＜ 0.05 ; MTT results (value A) 0.699 ± 0.050 vs 0.462 ± 0.080,0.912 ± 0.080 vs 0.535 ±0.040,0.726 ±0.050 vs 0.540 ±0.020,all P ＜0.05] and decelerated AEC Ⅱ transdifferentiation into AEC Ⅰ ; while AEC Ⅱ proliferation was inhibited in rhNF-κB group [cell numbers (× 109/L) 4.95 ± 0.33 vs 7.95 ± 0.65,4.73 ±0.71 vs 8.68 ± 0.52,4.04 ± 0.11 vs 8.73 ± 0.48,all P ＜ 0.05; MTT results (value A) 0.398 ± 0.030 vs 0.462 ± 0.080,0.402 ± 0.070 vs 0.535 ± 0.040,0.380 ± 0.110 vs 0.540 ± 0.020,all P ＜ 0.05] and accelerated AEC Ⅱ transdifferentiation into AEC Ⅰ.One-Way ANOVA showed that the difference among the 3 groups had statistical significance (cell numbers:F =486.73,P =0.02; cell proliferation:F =37.16,P =0.02).The mRNA expression:compared with control group,the expression of SP-C mRNA of Dlk1 group was significantly higher (P ＜ 0.05) while the expression of AQP5 mRNA was remarkably lower and delayed (P ＜ 0.05),the expression of Jagged1 mRNA was weak or little,Dlk1 and Notch1 mRNA were up-regulated (P ＜ 0.05),and the Hes1 mRNA was reduced (P ＜ 0.05) ; the expression of SP-C mRNA of rhNF-κB group was significantly reduced (P ＜ 0.05),while the AQP5 mRNA expressed ahead of time and increased (P ＜ 0.05),Jagged1,Hes1 and Notch1 mRNA were higher (P ＜ 0.05),and the Dlk1 mRNA was weak.One-Way ANOVA showed that the difference in the expressions of SP-C,AQP5,D1k1,Jagged1,Hes1 and Notch1 mRNA among the 3 groups had staistical significance (F =96.80,P =0.01 ; F =82.55,P =0.01 ; F =269.80,P=0.00;F =312.34,P =0.00;F =169.17,P =0.01;F =19.85,P =0.02).Conclusions There are varied effects on proliferation and differentiation of the AEC Ⅱ when the Notch signaling is activated by different ligands:Dlk1 promoted proliferation and inhibited differentiation,while Jagged1 inhibited proliferation and promoted transdifferentiation.
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Objective To determine the value of MR in the diagnosis of the medial and lateral meniscal posterior root tears.Methods One hundred and twenty one patients underwent arthroscopy and MR of knee examinations were retrospectively reviewed,and all of them did not have the history of knee surgery before the MR examination.MR images were double-blinded,independently,retrospectively scored by radiology residency (doctor 1) and attending radiologist (doctor 2).The likelihood of the meniscus posterior root tear was scored on basis of arthroscopic findings constituted the gold standard.Sensitivity,specificity and accuracy of MR diagnosis of the lateral and medial meniscus posterior root tear by two physicians were calculated,and the consistency of diagnosis results by two physicians was evaluated using the Kappa statistics.Reasons leading to misdiagnosis or missed diagnosis were discussed.Results Thirty three of the 121 patients were diagnosed with meniscus posterior root tears by arthroscopy,including 14 cases of lateral tears and 19 cases of medial tears.The sensitivity,specificity and accuracy in the diagnosis of posterior lateral meniscus root tears (PLMRT) for doctor 1 were 71.4％ (10/14),82.2％ (88/107) and 81.0％ (98/121),respectively,and for doctor 2 were 71.4％ (10/14),86.0％ (92/107) and 84.3％ (102/121).The sensitivity,specificity and accuracy in the diagnosis of posterior medial meniscus root tears (PMMRT) for doctor 1 were 100.0％ (19/19),88.2％ (90/102) and 90.1％ (109/121),respectively,and for doctor 2 were 100.0％ (19/19),95.1％ (97/102) and 95.9％ (116/121),respectively.The Kappa statistics for PLMRT and PMMRT were 0.67 and 0.81,respectively,demonstrating a good interobserver agreement (P＜0.05).The misdiagnosed cases of the PMMRT were 12 for doctor 1 and 5 for doctor 2.There were 4 cases being commonly misdiagnosed by the two doctors,and there were no any missed cases in this study.For the PLMRT,the misdiagnosed cases were 19 for doctor 1 and 15 for doctor 2.Eleven cases were misdiagnosed and 4 were missed by the two physicians.Conclusion MR is a reliable diagnostic tool for detecting posterior root tears of the medial and lateral meniscus.
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Objective To investigate the effect of hyperoxia on growth of type Ⅱ alveolar epithelial cells (AECⅡ).MethodsLungs of fetal rats at 19 days of pregnancy were collected,and AEC Ⅱ was isolated and cultured by differential adherence method.Cells were randomly divided into air group and hyperoxia group.In air group,cells were cultured in 5％ CO2 incubator.And cells in hyperoxia group were cultured in 5％ CO2+95％ O2 incubator.The growth,activity,cell cycle,cell apoptosis of AEC Ⅱ were observed at 2,4,6 and 8 days of culture.The interaction between different time and groups were analyzed by ANOVA of factorial design.Comparison of means was done by two-sample independent t test and one-way analysis of variance.Bonferroni correction was used during the comparisons.Results(1) Cell growth situation:in hyperoxia group,cell number was decreased from2 hto 8 h [(7.29±0.43)×105/ml,(2.68±0.37)×105/ml,(0.23±0.10)×105/ml and (0.00±0.00) × 105/ml],and lower than those in air group [(10.41 ± 0.24) × 105/ml,(27.90±1.91) × 105/ml,(27.12±0.85) ×105/ml and (26.29±1.59) × 105/ml](t=10.992,38.912,94.166and 49.696,P=0.000 respectively). (2) Cell activity:the living cells ratio in hyperoxia group at 2 d[(79.00±0.71) ％],4 d [(52.80±1.14)％] and 6 d [(31.60±1.52)％] was lower than those [(97.00±0.71)％,(97.20±0.84)％ and (95.00±0.71)％] ir air group (t=31.213,70.519 and 84.722,P=0.000 respectively).(3) Cell cycle:the cell ratios of G1 phase and S phase in hyperoxia group at day 4 [(66.82±1.20) ％ and (27.31±1.16) ％] and day 6 [(70.22±1.27) ％ and (30.31±1.40) ％] were significantly higher than that at day 2 and that in air group (P＜0.05 respectively).(4) Cell apoptosis:in hyperoxia group,the cell ratio of Annexin-V+/PI- subgroup at 4 h was the highest [(23.89 ± 0.52)％],followed by those at day 2 and 6 [(21.32 ± 0.43)％ and (1.47 ±0.61)％].While the cell ratio of Annexin-V+/PI+ was the highest at 6 h [(53.92± 1.64)％],followed by those at 4 h and 2 h [(45.03±1.01)％ and (12.17±0.60)％],which were all different with those in air group(P＜0.05 respectively).ConclusionsHyperoxia might inhibit cell activity and cell cycle of AEC Ⅱ and promote apoptosis.
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Objective To evaluate the correlation between diffusion tensor imaging(DTI)measurements,fiber tracking(FT)and the clinical symptoms in patients with cervical spondylotic myelopathy.Methods According to the Japanese orthopaedics association score(JOA),104 patients with cervical spondylopathy were divided into 4 groups:mild in 31 patients with 13-16 scores,moderate in 27 with 9-12 scores,severe in 25 with 5-8 scores,and serious in 21 with 0-4 scores.According to the lesion signal characters,all patients were divided into 3 groups:Group A with normal signal in both T1 WI and T2WI in 33 patients,Group B with normal signal in T1WI but high signal in T2WI in 30 patients,and Group C with low signal in T1 WI and high signal in T2WI in 41 patients.Apparent diffusion coefficient (ADC),fractional anisotropy(FA),λ1,λ2,λ3 were measured in the spinal cord at the serious pressed section,and fiber tractography was performed.The Spearman correlation analyses was used to correlate each of the DTI measurement with JOA score.Group difference was tested with one-way ANOVA method.Results High quality of DTI was acquired in all patients.The FA values in the mild,moderate,severe,and serious groups were respectively 0.69 ±0.13,0.58 ±0.03,0.46 ±0.08,and 0.37 ±0.11 and significant difference was found in different groups(F =100.59,P ＜ 0.05)and positively correlated with JOA scores (r =0.883,P ＜ 0.05).There was no statistical significance between JOA scores and ADC,λ1,λ2,λ3(r=0.232,0.217,0.113,0.127,P ＞0.05).The FA values in group A,B,and C were respectively 0.67 ±0.33,0.51 ±0.21,0.38 ±0.03,and significant difference was found among different groups(F =50.05,P ＜ 0.05).Decrease of JOA score and high signal in T2 companied with decrease of FA value.Decrease of FA values was found associated with increase of fiber bundle damage.The ADC,λ2,λ3 but not λ1 were significantly different among the JOA groups and the group A,B,and C.Conclusions The FA values are positively correlated with clinical symptoms.Decrease of FA values is found associated with increase of fiber bundle damage.DTI can show the severity and extent of damage of spinal cord in patients with cervical spondylotic myelopathy.
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Objective To observe the effects of phloroglucinol and diazepam on the progression of labor.Methods Two hundred normal primipara without indication of cesarean were randomly divided into intervention group and control group.When the cervix dilated 3 cm,the intervention group was given 80 mg phioroglueinol by injection of the cervix and 10 mg diazepam by injection of muscle,the control group was not given any drug.The length of labor stage,the different ways of labor,scores of neonate,volume of bleeding during 2 hours after labor of the two groups were observed.Results The pain degree of Ⅰ,Ⅱ,Ⅲ grade was 82,16,2 cases in intervention group,but 30,58,12 cases in control group,there was significant difference between the two groups(P＜0.01).The length of total labor stage and the first labor stage in intervention group were significant lower than those in control group(P＜0.05).the rate of spontaneous delivery in intervention group was higher than that in control group(P＜0.05),the others had no significant difference between the two groups(P＞0.05).Conclusions Phloroglueinol and diazepam can decurtate the length of labor stage and lessen pain and have no effects on both mother and newborn.It is worthwhile to spread the drugsin clinical practice.
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Objective To explore the effects of oxidative stress in the pathogenesis of lung injury and observe the influence of N-acetylcysteine (NAC). Methods The lung histopathology was observed by light microscope. The level of 8-iso-prostaglandin F2?lpha (8-iso-PGF2?) in blood plasm were measured by ELISA. The difference of 8-iso-PGF2? in blood plasm in air group, different dose NAC groups between hyperoxia-model and the air group was compared. Results In hyperoxia-model group, the inequality of size of lung alveoli, hemorrhage and inflammatory cell infiltration in lung alveoli were observed on the 3rd and 7th day. The alveolar septum was thick in the hyperoxic-damaged lungs on the 14th and the 21st day. In hyperoxia+high-dose NAC group, very small amounts of red blood cells leaked out into alveoli on the 3rd and 7th day and alveolar septum had no thickening obviously on the 14th day and the 21st day. The level of 8-iso-PGF2? in blood plasm in hyperoxia-model group [(28.33?5.57) pg/ml, (51.21?15.01) pg/ml, (84.54?14.85) pg/ml and (43.14?11.37) pg/ml at every time points] was higher than that of the air group and hyperoxia+high-dose NAC group(P